bims-axbals 2025-08-24 papers

bims-axbals

Biomed News

on Axonal biology and ALS

Issue of 2025–08–24
37 papers selected by
TJ Krzystek

A Slower-Progressing TDP-43 rNLS8 Mouse Model for ALS: Implications for Preclinical and Mechanistic Studies.
Increased neuronal activity restores circadian function in Drosophila models of C9orf72-ALS/FTD.
Influence of palmitoylation in axonal transport mechanisms in neurodegenerative diseases.
Nuclear pore complex dysfunction drives TDP-43 pathology in ALS.
Ropinirole Functions Through a Dopamine Receptor D2-Independent Mechanism to Ameliorate Amyotrophic Lateral Sclerosis Phenotypes in TARDBP-Mutant iPSC-Derived Motor Neurons.
Neurochemical biomarkers of amyotrophic lateral sclerosis: recent developments.
TDP-43 pathology is associated with divergent protein profiles in ALS brain and spinal cord.
A role for the autophagy receptor NBR1 in the degradation of tau aggregates.
Loss of Drosophila ribosomal protein S6 kinase II causes mitochondrial dysfunction and cell death.
Novel Leucine-Rich Repeat Kinase 2 (LRRK2) Inhibitors for the Treatment of Parkinson's Disease.
Cell type-specific alterations in excitability and inhibition of upper motor neurons in AlsinKO mice, a model of juvenile onset ALS.
Use of Proteomics to Explore Biomarkers of Amyotrophic Lateral Sclerosis (ALS): Proof of Principle from Humanized SOD1 Mouse to Human ALS.
High-fat diet impairs intermediate-term memory by autophagic-lysosomal dysfunction in Drosophila.
Proteostasis and Unfolded Protein Response Dynamics in Human Neuron and Mouse Glia Co-culture Reveal Cell-Specific Aging Responses.
The emerging role of cellular senescence in amyotrophic lateral sclerosis.
The Hsp40 co-chaperone DNAJC7 modifies polyglutamine but not polyglycine aggregation.
Antisense oligonucleotide therapy in amyotrophic lateral sclerosis.
cnnm-5 knockdown improves proteostasis of mutant Huntingtin protein in C. elegans.
Functional recovery by transplantation of human iPSC-derived A2B5 positive neural progenitor cell after spinal cord injury in mice.
Generation of three human induced pluripotent stem cell (hiPSC) lines from patients with Late-Onset Tay-Sachs disease (HEXA-related adult-onset GM2-gangliosidosis).
Biogenesis, action, function of plant small RNAs and their potential application in agriculture.
Novel In Vitro Culture of Microglia from Aged Mice: Implications for the Future of Aging Neurobiology Research.
Transposable element expression and sub-cellular dynamics during hPSC differentiation to endoderm, mesoderm, and ectoderm lineages.
Biallelic variants in COX18 cause a mitochondrial disorder primarily manifesting as peripheral neuropathy.
Sevoflurane inhibition of the developmentally expressed neuronal sodium channel Nav1.3.
A modular and reconfigurable microfluidic device for culturing spheroids under continuous perfusion.
Astrocyte Secretome Profiling via Biorthogonal Labeling Unveils Novel Factors Relevant to Neurodegenerative Diseases.
Specific Combinations of Physiological Tau Phosphorylation Regulate Tau-Microtubule Interactions in Developing Neurons.
Centrosomal P4.1-associated protein (CPAP) is a novel regulator of ESCRT pathway function during multivesicular body formation and endosome maturation.
Circular continuum of alpha motoneuron types.
From thought to action: The organization of spinal projecting neurons.
Abnormal neurodevelopment predisposes to cortical hyperexcitability in Huntington's disease.
Vesicle tension in porous membranes: aspiration, spreading, and tube extraction.
The mevalonate pathway couples lipid metabolism to amino acid synthesis via ubiquinone-dependent redox control.
Inhibition of UBE2N promotes the clearance of mutant HTT (huntingtin) in HD knock-in mice.
Molecular chameleons adaptability in target binding.
Predictable Modulation of a Spontaneous Post-translational Modification in Living Cells.

Neuromolecular Med. 2025 Aug 18. 27(1): 59

A Slower-Progressing TDP-43 rNLS8 Mouse Model for ALS: Implications for Preclinical and Mechanistic Studies.

Cyril Jones Jagaraj, Prachi Mehta, Julie Hunter, Julie D Atkin.

  Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterised by motor neuron degeneration, muscle weakness, paralysis, and eventual death, with TAR DNA-binding protein 43 (TDP-43) pathology observed in almost all cases. Mouse models based on TDP-43 are thus essential for studying ALS and developing therapeutic approaches. The TDP-43 rNLS8 mouse model expresses a human TDP-43 transgene with a mutated nuclear localization sequence (hTDP-43 ΔNLS), but this is normally suppressed by the presence of doxycycline (Dox). Disease is initiated by removal of Dox, which replicates key ALS features, including TDP-43 pathology, neuromuscular junction denervation, motor neuron loss, and reduced survival. However, this model has a rapid disease progression which limits its use for extended preclinical studies and investigation of early disease mechanisms. To overcome these limitations, we explored whether maintaining low Dox concentrations in the diet (10-20 mg/kg) could slow disease progression. Our findings demonstrate that this approach significantly reduced hTDP-43 ΔNLS expression (up to 4.8-fold), which delayed disease onset by four weeks. Disease progression, assessed by rotarod performance, grip strength, and neurological scores, was extended from six to 15 weeks, with a threefold increase in survival. Despite slower progression, at the end stage, mice displayed similar levels of neuroinflammation, motor neuron loss, as Dox off mice. These findings highlight slower-progressing TDP-43 rNLS8 mice as a robust model for preclinical and early disease mechanism studies.

Keywords:  ALS; Longer disease course; TDP-43 rNLS8 mice model

DOI:  https://doi.org/10.1007/s12017-025-08871-z
bioRxiv. 2025 Aug 11. pii: 2025.08.07.669085. [Epub ahead of print]

Increased neuronal activity restores circadian function in Drosophila models of C9orf72-ALS/FTD.

Sho Inami, Benjamin P Jenny, Oghenerukevwe Akpoghiran, Sara I Gallagher, Alexandra K Strich, Ayako Tonoki, Davide Trotti, Aaron R Haeusler, Kyunghee Koh.

Circadian rhythm disruptions are common across neurodegenerative diseases, but their link to amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) remains unclear. The C9orf72 hexanucleotide repeat expansion is the most prevalent genetic cause of ALS/FTD. Here, we used Drosophila models expressing toxic arginine-rich dipeptides (PR or GR) or GGGGCC hexanucleotide repeats to investigate circadian deficits in C9orf72-ALS/FTD. We found that circadian rhythmicity and period length were disrupted in a repeat number-, dosage-, and age-dependent manner. Additionally, we observed lower levels of the neuropeptide PDF, a key regulator of free-running circadian rhythms, as well as decreased projection complexity and reduced neuronal activity in PDF-expressing neurons. Importantly, increases in neuronal activity significantly restored circadian function under select conditions. These results implicate reduced neuronal activity in C9orf72-ALS/FTD circadian deficits, underscoring the importance of precisely tuned, circuit- and stage-specific interventions.
Highlights: C9orf72 dipeptide and nucleotide repeats disrupt circadian rhythms in Drosophila Circadian dysfunction with reduced PDF and neurites emerges before neuron lossIncreased neuronal activity rescues mild circadian dysfunctionActivity-based rescue is effective across ages and models when precisely tuned.

DOI: https://doi.org/10.1101/2025.08.07.669085
Front Cell Neurosci. 2025 ;19 1613379

Influence of palmitoylation in axonal transport mechanisms in neurodegenerative diseases.

Praveen B S, Priti Talwar.

  Progressive functional loss and death of neurons are characteristics of neurodegenerative diseases such as Alzheimer's disease (AD), Amyotrophic lateral sclerosis (ALS), and Parkinson's disease (PD). These diseases are often linked with disruptions in axonal transport and synaptic functions. Accumulation of misfolded proteins is observed as a commonly shared pathology for these diseases, where aberrant accumulation of amyloid beta (Aβ), tau, α-synuclein (α-syn) and TAR DNA-binding protein 43 (TDP-43), are found in AD, PD and ALS, respectively. These accumulations are observed to be involved in disrupting axonal transport and compromising neuronal survival. Axonal transport is an essential process where proper functioning of the transport mechanism is important for maintaining neuronal hemostasis by transporting of proteins, organelles and neurotransmitter complexes. This review explores the role of palmitoylation in regulating neuronal axonal transport and their impact on other neuronal functions along with neurodegeneration mechanisms. Palmitoylation is a reversible lipid modification, which is widely studied second to phosphorylation. Enzymes like palmitoyl acyltransferases and acyl-protein thioesterases are responsible for attachment and detachment of palmitic acid causing palmitoylation and depalmitoylation of neuronal proteins. In axonal transport, palmitoylation influences the localization and functioning of the proteins, which connectively plays a role in synaptic stability by interacting with synaptic scaffolding proteins and neurotransmission receptors.

Keywords:  axonal transport; depalmitoylation; neurodegenerative diseases; palmitoylation; zDHHC

DOI:  https://doi.org/10.3389/fncel.2025.1613379
Redox Biol. 2025 Aug 14. pii: S2213-2317(25)00337-4. [Epub ahead of print]86 103824

Nuclear pore complex dysfunction drives TDP-43 pathology in ALS.

O Ramírez-Núñez, S Rico-Ríos, P Torres, V Ayala, A Fernàndez-Bernal, M Ceron-Codorniu, P Andrés-Benito, A Vinyals, S Maqsood, I Ferrer, R Pamplona, M Portero-Otin.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by progressive motor neuron degeneration and pathological aggregation of TDP-43. While protein misfolding and impaired autophagy are established features, accumulating evidence highlights the nuclear pore complex (NPC)as a vulnerable, redox-sensitive hub in ALS pathogenesis. Here, we show that selective loss of NPC components, particularly the scaffold proteins NUP107 and NUP93, and FG-repeat-containing components-is a consistent finding across ALS postmortem spinal cord, SOD1^G93A and TDP-43 mutant mouse models, and human cell systems.CRISPR-mediated depletion of NUP107 in human cells triggers hallmark features of ALS pathology, including cytoplasmic TDP-43 mislocalization, increased phosphorylation, and autophagy dysfunction. Conversely, TDP-43 knockdown perturbs NPC composition, suggesting a reciprocal regulatory loop. Crucially, we demonstrate that oxidative stress exacerbated NPC subunit mislocalization and enhanced TDP-43 aggregation. Using oxime blotting and DNPH assays, we show that FG-repeat subunits of NPC were direct targets of redox-driven carbonylation, indicating that oxidative modifications compromise NPC integrity thuspotentially affecting nucleocytoplasmic transport. Our findings established NPC dysfunction as a redox-sensitive driver of TDP-43 pathology in ALS and highlight nucleocytoplasmic transport as a promising therapeutic axis. The susceptibility of long-lived NPC proteins to oxidative damage provides a mechanistic link between redox stress, proteostasis collapse, and neurodegeneration.

DOI: https://doi.org/10.1016/j.redox.2025.103824
J Neurochem. 2025 Aug;169(8): e70183

Ropinirole Functions Through a Dopamine Receptor D2-Independent Mechanism to Ameliorate Amyotrophic Lateral Sclerosis Phenotypes in TARDBP-Mutant iPSC-Derived Motor Neurons.

Hirotsugu Asano, Tetsuya Kawaguchi, Chris Kato, Satoru Morimoto, Masato Yano, Maki Minaguchi, Daisuke Yasuda, Komei Fukushima, Hideyuki Okano.

  Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by motor neuron (MN) degeneration. Ropinirole hydrochloride (ROPI), a dopamine receptor D2 (DRD2) agonist, was identified through phenotypic screening of MNs derived from patient-derived induced pluripotent stem cells (iPSCs) as a disease model and has emerged as a promising candidate drug for ALS treatment. The ROPALS trial, a phase I/IIa trial in patients with ALS, suggested the safety and efficacy of ROPI, albeit in a small sample size. Interestingly, a DRD2 antagonist and modulator only partially mitigated the suppressive effect of ROPI on the ALS phenotype, and the detailed mechanism of ROPI activity remains unclear. Therefore, in this study, we investigated whether the therapeutic effects of ROPI in ALS are dependent on DRD2. For this purpose, we generated DRD2-deficient iPSCs and showed that ROPI effectively reduced neuronal cell death, reactive oxygen species (ROS) production, and neuronal hyperexcitation, independently of DRD2. Further analyses revealed that ROPI corrected aberrant RNA splicing and restored the mRNA expression of mitochondrial proteins in a DRD2-independent manner. Our findings suggest that ROPI not only functions as a canonical DRD2 agonist but also has pleiotropic DRD2-independent effects, offering a novel avenue for treatment strategies that target multiple pathways involved in ALS pathology.

Keywords:  TARDBP; aberrant RNA splicing; amyotrophic lateral sclerosis; dopamine D2 receptor; neuronal hyperexcitation; ropinirole

DOI:  https://doi.org/10.1111/jnc.70183
Curr Opin Neurol. 2025 Aug 20.

Neurochemical biomarkers of amyotrophic lateral sclerosis: recent developments.

Federico Verde.

   REVIEW PURPOSE: To provide an overview of the recent developments in the field of neurochemical biomarkers of amyotrophic lateral sclerosis (ALS).
RECENT FINDINGS: Neurofilaments, especially NFL, have been confirmed to be good biomarkers for ALS. NFL may be diagnostically useful but its main role is as prognostic and pharmacodynamic biomarker. Inflammatory biomarkers, especially the chitinases, might also serve as pharmacodynamic biomarkers in treatment trials targeting neuroinflammation. GFAP could reflect cognitive-behavioural impairment. CSF dipeptides are diagnostic biomarkers for ALS caused by the C9ORF72 exanucleotide repeat expansion and may be used to confirm target engagement by experimental drugs. Levels of TDP-43 (virtually the ideal biomarker for ALS) in CSF and plasma have not been demonstrated to be consistently altered in ALS. However, promising advancements have been achieved in seed amplification assays for the protein, in its quantification in plasma extracellular vesicles, and in the measurement of CSF levels of a protein reflecting splicing dysfunction of TDP-43. Finally, blood phosphorylated tau has emerged as an ALS biomarker linked to lower motor neuron (or muscle) pathology.
SUMMARY: NFL is still the best neurochemical biomarker for ALS. However, substantial advances have been recently made, especially regarding detection of TDP-43 and blood phosphorylated tau.

Keywords:  TDP-43; amyotrophic lateral sclerosis; biomarkers; neurofilament light chain; phosphorylated tau (P-tau)

DOI:  https://doi.org/10.1097/WCO.0000000000001411
Acta Neuropathol Commun. 2025 Aug 18. 13(1): 175

TDP-43 pathology is associated with divergent protein profiles in ALS brain and spinal cord.

Emily Feneberg, Alexander G Thompson, Philip D Charles, Iolanda Vendrell, Benedikt M Kessler, Roman Fischer, Olaf Ansorge, Elizabeth Gray, Kevin Talbot, Martin R Turner.

  Neuronal and glial cytoplasmic inclusions positive for TAR DNA-binding protein 43 (TDP-43) are the defining pathological hallmark of 97% of amyotrophic lateral sclerosis (ALS) and 50% of frontotemporal dementia (FTD). The ALS-FTD clinicopathological spectrum variably involves cortical and spinal anterior horn cell pathology. The broader protein composition of these inclusions is of major importance to understanding pathogenesis, clinical heterogeneity and biomarker development. This study examined the proteome associated with TDP-43 inclusions in ALS, using mass spectrometry-based proteomic analysis of spinal cord and cerebral cortex from donors with phosphoTDP-43 positive ALS (n = 16), alpha-synuclein positive Parkinson's disease (PD, n = 8), phosphotau and beta-amyloid positive Alzheimer's disease (AD, n = 8) and age matched non-neurological controls (n = 8), comparing ALS with non-ALS conditions, spinal cord with cerebral cortex samples, and detergent-soluble with -insoluble fractions. Increased abundance of TDP-43 in the detergent-insoluble fraction of ALS cortex and spinal cord tissue confirmed disease-specific protein enrichment by serial fractionation. The most striking alterations between ALS and other conditions were found in the detergent-insoluble fraction of spinal cord, with predominant enrichment of endosomal and extracellular vesicle pathways. In the cortex mitochondrial membrane/envelope and ion transmembrane transport pathways were enriched in the detergent-insoluble fraction. RNA/DNA metabolic processes (in spinal cord) versus mitochondrial and synaptic protein pathways (in cortex) were upregulated in the detergent-soluble fraction of ALS cases and downregulated in the insoluble protein fraction. Whilst motor cortex and spinal cord may not optimally reflect disease-specific pathways in AD, in PD a significant enrichment of alpha-synuclein in the detergent-insoluble fraction of spinal cord was found. Among proteins concordantly elevated in the detergent-insoluble fractions of spinal cord and cortex, there was greater representation of proteins encoded by ALS-associated genes, specifically Cu/Zn superoxide dismutase 1, valosin containing protein and TDP-43 (odds ratio 16.34, p = 0.002). No significant increase in TDP-43 interacting proteins was observed in either detergent-soluble or -insoluble fractions. Together, this study shows a divergence in the composition of proteins associated with TDP-43 positive detergent-insoluble inclusions between spinal cord and cerebral cortex. A common upregulation of proteins encoded by ALS-causing genes implicates their role in the pathogenesis of the ALS-FTD spectrum of diseases beyond TDP-43. Data are available via ProteomeXchange with identifier PXD067060.

Keywords:  Amyotrophic lateral sclerosis; Brain; Proteomics; Spinal cord; TDP-43; Tissue

DOI:  https://doi.org/10.1186/s40478-025-02084-y
Neurobiol Dis. 2025 Aug 14. pii: S0969-9961(25)00276-1. [Epub ahead of print]214 107060

A role for the autophagy receptor NBR1 in the degradation of tau aggregates.

Marie Neu, Iwan Parfentev, Gregory K Potts, Nina Stöberl, Jürgen Korffmann, Andreas Striebinger, Daniela Geist, Dimitris Papageorgiou, Hanna Tarhonskaya, Nicholas McKitterick, Jeroen van Bergeijk, Christopher Untucht, Peter Reinhardt, Jon D Williams, Michaela J Heimann, Laura Gasparini, Dagmar E Ehrnhoefer.

  Neurofibrillary tangles (NFTs), comprising hyperphosphorylated and aggregated Tau protein, are a primary neuropathological feature of Alzheimer's Disease (AD). In patients, the formation and spread of NFTs across the brain correlate with cognitive decline. However, the mechanisms driving Tau aggregation and leading to the subsequent neuronal dysfunction are not fully understood. In this study, we explored proteomic and phosphoproteomic changes resulting from the seed-induced aggregation of endogenous Tau in human neurons, derived from induced pluripotent stem cells (iPSCs). We discovered previously undescribed phosphorylation sites on NBR1, an autophagy receptor, which were significantly altered by Tau aggregation in vitro. We further show that NBR1 directly interacts with phosphorylated Tau and Tau aggregates in various cellular models. This interaction is associated with autophagic Tau degradation in HEK biosensor cells, and siRNA-mediated knockdown of NBR1 significantly increases Tau aggregate levels in iPSC-derived neurons. Additionally, we find that NBR1 expression is significantly increased in AD patients, and it specifically interacts with Tau in human AD brain, underscoring the relevance of our findings to the human disease. These insights provide a deeper understanding of the molecular interactions between autophagy receptors and Tau pathology in AD and reveal a role for NBR1 as an important receptor for pathological forms of Tau.

Keywords:  Alzheimer's disease; Autophagy receptor; Mass spectrometry; Phosphoproteomics; Proteomics; Tau aggregation; iPSC-derived neurons

DOI:  https://doi.org/10.1016/j.nbd.2025.107060
Dis Model Mech. 2025 Aug 01. pii: dmm052374. [Epub ahead of print]18(8):

Loss of Drosophila ribosomal protein S6 kinase II causes mitochondrial dysfunction and cell death.

Ting Deng, Lajos Kalmar, Samantha Loh, Olivier E Pardo, L Miguel Martins.

  Mitochondria are dynamic organelles that are critical for energy production in high-demand tissues, such as the brain and muscle, with fusion and fission maintaining network integrity. The dysregulation of these processes underlies pathologies, such as neurodegenerative diseases. Ribosomal S6 kinases (RSK1-4) are effectors of extracellular signal-regulated kinases (ERKs), with roles in cell survival and metabolism. Here, we show that RSKs are essential for mitochondrial health. In human cells, siRNAs targeting any RSK isoform (RSK1-4) induced mitochondrial fragmentation and reduced viability. In Drosophila melanogaster, CRISPR-mediated loss of S6kII (the sole RSK orthologue) caused mitochondrial dysfunction and tissue degeneration in high-energy-demand organs, including the indirect flight muscle and brain, accompanied by autophagic activation. Notably, we rescued these defects by expressing human RSK4, underscoring functional conservation. Our findings establish RSKs as critical regulators of mitochondrial integrity, linking ERK signalling to organelle dynamics. This work identifies RSKs as regulators of mitochondrial health in energy-demanding tissues, providing insights into the mechanisms underlying neurodegeneration and strategies to target ERK/RSK-driven mitochondrial dysfunction.

Keywords:   Drosophila ; Cell death; Kinase; Mitochondria

DOI:  https://doi.org/10.1242/dmm.052374
ACS Med Chem Lett. 2025 Aug 14. 16(8): 1511-1512

Novel Leucine-Rich Repeat Kinase 2 (LRRK2) Inhibitors for the Treatment of Parkinson's Disease.

Zhendong Song, Steven H Liang.

This patent describes novel leucine-rich repeat kinase 2 (LRRK2) inhibitors featuring a 2,4,12,13-tetrahydro-11H-5,7-(azenometheno)-dipyrazolo-[3,4-b:5',1'-g]-[1]-oxa-[4,6,8]-triazacycloundecine scaffold. These LRRK2 inhibitors exhibit therapeutic potential for the treatment of Parkinson's disease.

DOI: https://doi.org/10.1021/acsmedchemlett.5c00438
J Neurosci. 2025 Aug 19. pii: e2409242025. [Epub ahead of print]

Cell type-specific alterations in excitability and inhibition of upper motor neurons in AlsinKO mice, a model of juvenile onset ALS.

Soumil Dey, Christopher Quintanilla, Dila Bitlis, Mukesh Gautam, P Hande Ozdinler, Marco Martina.

In amyotrophic lateral sclerosis (ALS) motor cortex hyperexcitability is detected in both familial and sporadic cases, suggesting its centrality in the ALS phenotype; the underlying mechanisms, however, remain largely obscure. Here we utilize male and female UCHL1-eGFP (UeGFP) mice, in which the corticospinal neurons of the motor cortex are labeled with green fluorescent protein, to investigate the intrinsic excitability and synaptic inhibitory inputs on distinct neuron populations in WT-UeGFP and presymptomatic AlsinKO-UeGFP mice, which lack Alsin function and are a well-characterized mouse model for juvenile cases of ALS. We show that in the motor cortex of AlsinKO-UeGFP mice, eGFP-positive layer 5 pyramidal neurons, which represent upper motor neurons, show a decrease in intrinsic excitability compared with WT, whereas the electrophysiological properties of eGFP-negative cells, which identify callosal projection neurons, are unaffected. This alteration in intrinsic excitability, however, is counterbalanced by a decrease in the frequency of spontaneous inhibitory currents due to a cell-specific reduction in the number of inhibitory synaptic contacts on upper motor neurons. Thus, the overall excitability of upper motor neurons only displays negligible changes despite large alterations in intrinsic excitability and inhibitory synaptic input, which may explain why mice do not exhibit a prominent motor phenotype. The presence of this homeostatic interaction between intrinsic excitability and synaptic inhibition raises the question of which of the two changes is primary, and which is secondary, and shows that decreased function of motor cortex interneurons is an early event in ALS with Alsin mutations.Significance Statement We found that in AlsinKO mice, which recapitulate ALS disease in patients with Alsin mutations, intrinsic excitability and inhibitory synaptic input of upper motoneurons (but not callosal-projection neurons) are significantly reduced at presymptomatic disease stage. We show that in this model: 1) impaired function of cortical interneurons is an early event; 2) excitability alteration in the motor cortex is cell type-specific; 3) intrinsic excitability and synaptic inhibition are linked by a homeostatic mechanism. These results stress the importance of cortical interneurons in ALS and suggest that either homeostatic overcompensation or failure of compensation contribute to disease onset and progression. If these mechanisms are common in ALS patients, this may have important consequences for the design of novel therapeutic interventions.

DOI: https://doi.org/10.1523/JNEUROSCI.2409-24.2025
ACS Pharmacol Transl Sci. 2025 Aug 08. 8(8): 2415-2430

Use of Proteomics to Explore Biomarkers of Amyotrophic Lateral Sclerosis (ALS): Proof of Principle from Humanized SOD1 Mouse to Human ALS.

Nitesh Sanghai, Geoffrey K Tranmer.

  Amyotrophic lateral sclerosis (ALS) is a rare motor neurodegenerative disease affecting multiple cellular proteins during the progression of the disease. ALS was first discovered by Charcot in 1869, and since then, scientists have been unable to identify a singular cause of the disease. Further, there are no effective treatments available to cure ALS. The benchmark discovery of humanized preclinical SOD1 mouse models, which recapitulates the clinical and pathological phenotypes of human ALS, gives hope to medicinal chemists and neuroscientists around the globe that a suitable drug-like molecule can be discovered and translated into human beings as a means to slow down the progression of the disease. However, little success has been achieved until now in terms of finding an effective treatment for heterogenic and incurable ALS. One area marked for improvement is the use of semiquantitative, antibody-based targeted Western blotting (WB) experiments, which lack the power to analyze multiple cellular events within the entire dysregulated proteomic system. With the inconsistency of WB experiments, unexpected cellular pathways go undiscovered, and hence, loss of translation with no target engagement is seen from preclinical to human clinical ALS. Recent advancements in discovery-based quantitative proteomics have many advantages over WB. These innovative techniques could help solve the inherent problem in WB and their inability to discover multiple altered proteins with the added capability of longitudinal analysis in preclinical SOD1 models, further validating the findings in human ALS. Herein, we applied a holistic approach to summarize various reports on the use of proteomics in ALS from the published literature, and importantly, we found that using a discovery-based proteomics approach in SOD1 preclinical ALS models has revealed a more diverse and global picture of pathological proteins that affect multiple pathways during different stages of disease progression. Furthermore, we found that the proteomic profiling of the humanized SOD1 mouse model provided a proof of principle for translating the diverse pathological biomarker proteins identified in clinical human ALS cases. Moreover, we believe that advancements in the proteomics approach toward ALS biomarkers could bridge the gap between preclinical and clinical studies, enabling scientists worldwide to discover novel biomarkers and treatments that modify the progression of ALS.

Keywords:  Western blotting; amyotrophic lateral sclerosis; biomarkers; humanized SOD1 mouse model; proteomics; target engagement

DOI:  https://doi.org/10.1021/acsptsci.5c00403
PLoS Genet. 2025 Aug;21(8): e1011818

High-fat diet impairs intermediate-term memory by autophagic-lysosomal dysfunction in Drosophila.

Tong Yue, Minrui Jiang, Kotomi Onuki, Motoyuki Itoh, Ayako Tonoki.

High-fat diet (HFD) is considered a risk factor for age-related memory impairments such as Alzheimer's disease. However, how HFD affects memory formation remains unclear. In this study, we established a model of memory defects caused by HFD in Drosophila. Our results revealed that the HFD impaired intermediate-term memory (ITM), but not short-term memory (STM), produced by classical aversive olfactory conditioning, and decreased autophagic activity in the heads of the HFD-fed flies. Transient reduction in autophagic activity also impaired ITM, but not STM. Genetic enhancement of autophagic activity in neurons effectively restored ITM performance in the HFD-fed flies. Mechanistically, HFD impairs lysosomal function by downregulating the expression of lysosome-related genes, leading to impaired fusion of autophagosomes with lysosomes. These findings suggest that HFD impairs ITM by reducing autophagic activity and lysosomal dysfunction in the neurons.

DOI: https://doi.org/10.1371/journal.pgen.1011818
bioRxiv. 2025 Aug 13. pii: 2025.08.11.669714. [Epub ahead of print]

Proteostasis and Unfolded Protein Response Dynamics in Human Neuron and Mouse Glia Co-culture Reveal Cell-Specific Aging Responses.

Lea A Barny, Sarah K Garcia, Aiden J Houcek, Burak Uzay, Minsoo Kim, Ege T Kavalali, Lars Plate.

Proteostasis, or protein homeostasis, is a tightly regulated network of cellular pathways essential for maintaining proper protein folding, trafficking, and degradation. Neurons are particularly vulnerable to proteostasis collapse due to their post-mitotic and long-lived nature and thus represent a unique cell type to understand the dynamics of proteostasis throughout development, maturation, and aging. Here, we utilized a dual-species co-culture model of human excitatory neurons and mouse glia to investigate cell type- specific, age-related changes in the proteostasis network using data-independent acquisition (DIA) LC-MS/MS proteomics. We quantified branch-specific unfolded protein response (UPR) activation by monitoring curated effector proteins downstream of the ATF6, IRE1/XBP1s, and PERK pathways, enabling a comprehensive, unbiased evaluation of UPR dynamics during neuronal aging. Species-specific analysis revealed that aging neurons largely preserved proteostasis, although they showed some signs of collapse, primarily in ER-to-Golgi transport mechanisms. However, these changes were accompanied by upregulation of proteostasis-related machinery and activation of the ATF6 branch, as well as maintenance of the XBP1s and PERK branches of the UPR with age. In contrast, glia exhibited broad downregulation of proteostasis factors and UPR components, independent of neuronal presence. Furthermore, we quantified stimulus-specific modulation of select UPR branches in aged neurons exposed to pharmacologic ER stressors. These findings highlight distinct, cell-type-specific stress adaptations during aging and provide a valuable proteomic resource for dissecting proteostasis and UPR regulation in the aging brain.
Significance: Understanding how the unfolded protein response (UPR) and proteostasis network change with age is often studied in model organisms, where pathways are assessed across mixed cell types. Such systems can obscure cell-type-specific regulation. Here, we evaluate age-associated remodeling of the UPR and proteostasis network in a dual-species co-culture of human neurons and mouse glia using DIA proteomics. This approach enables species-specific proteomic profiling without physical separation, supported by a customizable data analysis pipeline. We show that neurons and glia exhibit divergent age-related responses, with neurons maintaining adaptive proteostasis and glia showing broader declines. The analytical framework presented here supports future studies to uncover additional cell-type-specific aging phenotypes or to probe the effects of pharmacologic or physical manipulation of biological systems.

DOI: https://doi.org/10.1101/2025.08.11.669714
Front Neurosci. 2025 ;19 1599492

The emerging role of cellular senescence in amyotrophic lateral sclerosis.

Xingli Tan, Naiyong Gao.

  Cellular senescence is a state of permanent cell cycle arrest and is considered a key contributor to aging and age-related diseases, including amyotrophic lateral sclerosis (ALS). The physiological processes of aging lead to a variety of molecular and cellular phenotypes, and evidence of overlap between ALS and aging-related biomarkers suggests that cell type-specific senescence may be a critical factor in ALS. Senescent microglial cells, astrocytes, and neurons have been detected in ALS patients and animal models. However, while accumulating evidence suggests a potential link between cellular senescence and ALS, this connection remains not yet conclusively established. Importantly, how senescent cells may contribute to the neuropathophysiology of ALS remains largely unknown. Additionally, the growing popularity of anti-aging therapies has highlighted the potential of senescent cell clearance as a promising strategy for treating age-related diseases, including ALS. This review provides an overview of cellular senescence, discusses recent advances in understanding how senescence in different cell types influences ALS pathogenesis, and explores the potential role of anti-senescence therapies in ALS treatment.

Keywords:  aging; aging of motor neurons; amyotrophic lateral sclerosis; anti-senescence; cellular senescence

DOI:  https://doi.org/10.3389/fnins.2025.1599492
bioRxiv. 2025 Aug 12. pii: 2025.08.10.669490. [Epub ahead of print]

The Hsp40 co-chaperone DNAJC7 modifies polyglutamine but not polyglycine aggregation.

Biswarathan Ramani, Kean Ehsani, Martin Kampmann.

Polyglutamine (polyQ) diseases, including Huntington's disease and several spinocerebellar ataxias, are caused by abnormally expanded CAG nucleotide repeats, which encode aggregation-prone polyQ tracts. Substantial prior evidence supports a pathogenic role for polyQ protein misfolding and aggregation, with molecular chaperones showing promise in suppressing disease phenotypes in cellular and animal models. In this study, we developed a FRET-based reporter system that models polyQ aggregation in human cells and used it to perform a high-throughput CRISPR interference screen targeting all known molecular chaperones. This screen identified as a strong suppressor of polyQ aggregation the Hsp40 co-chaperone DNAJC7, which has previously been shown to modify aggregation of other disease proteins (tau and TDP-43) and has mutations causative for amyotrophic lateral sclerosis. We validated this phenotype and further established a physical interaction between DNAJC7 and polyQ-expanded protein. In contrast, DNAJC7 did not modify aggregation of polyglycine (polyG) in a FRET-based model of neuronal intranuclear inclusion disease. In addition to establishing new inducible, scalable cellular models for polyQ and polyG aggregation, this work expands the role of DNAJC7 in regulating folding of disease-associated proteins.

DOI: https://doi.org/10.1101/2025.08.10.669490
Curr Opin Neurol. 2025 Aug 20.

Antisense oligonucleotide therapy in amyotrophic lateral sclerosis.

Gergo Erdi-Krausz, Pamela J Shaw.

   PURPOSE OF REVIEW: Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder with few treatment options available. The approval of tofersen, an antisense oligonucleotide, for SOD1-ALS by the FDA and EMA may herald a new era of treatment in these patients.
RECENT FINDINGS: So far, trials against the most common genetic form of ALS, C9orf72, have been unsuccessful, but new preclinical data may show a promising new direction to take. Clinical trials targeting other, more rare genetic mutations associated with familial ALS are currently underway. Other research assessing the use of ASOs to target aberrant splicing associated with sporadic forms of ALS has also produced promising results in preclinical models, using patient-derived induced cellular models and animal models. These therapies are focussed largely on alleviating and reversing TDP-43 pathology, opening up the possibility of not only arresting disease progression, but reversing neurodegeneration.
SUMMARY: ASO therapies have made some promising steps towards treating familial ALS, particularly SOD1. Ongoing early clinical/preclinical phase research is underway to utilise this technology in other genetic mutations linked with ALS, as well as in sporadic cases.

Keywords:  ; amyotrophic lateral sclerosis; antisense oligonucleotides

DOI:  https://doi.org/10.1097/WCO.0000000000001413
MicroPubl Biol. 2025 ;2025

cnnm-5 knockdown improves proteostasis of mutant Huntingtin protein in C. elegans.

Matthew Hull, Joslyn Mills.

Huntington's disease (HD) is an age-related neurodegenerative disease associated with the aggregation of mutant Huntingtin protein (mHTT). It is theorized that prevention or clearance of these aggregates through autophagy and the ubiquitin proteasome system (UPS) protects neurons from degeneration. Using a C. elegans model of HD, a small reverse genetic screen of 100 random genes on Chromosome 3 identified cnnm-5 as a genetic modifier of mHTT accumulation. During development, loss of cnnm-5 by RNAi ( cnnm-5 i) protects against mHTT accumulation, implicating cnnm-5 as a negative regulator of protein aggregation prevention or clearance. Here we report that knocking down cnnm-5 leads to decreased mHTT protein aggregation through the upregulation of the UPS and autophagy pathways, leading to increased lifespan. Further experimentation using a nematode model of Alzheimer's disease demonstrates cnnm-5 i protects against paralysis by decreasing beta amyloid protein misfolding in body wall muscles.

DOI: https://doi.org/10.17912/micropub.biology.001497
bioRxiv. 2025 Aug 15. pii: 2025.08.12.669912. [Epub ahead of print]

Functional recovery by transplantation of human iPSC-derived A2B5 positive neural progenitor cell after spinal cord injury in mice.

Yiyan Zheng, Xiaohui Chen, Ping Bu, Haipeng Xue, Dong H Kim, Hongxia Zhou, Xugang Xia, Ying Liu, Qilin Cao.

Human induced pluripotent stem cells (hiPSCs) hold great potential for patient-specific therapies. Transplantation of hiPSC-derived neural progenitor cells (NPCs) is a promising reparative strategy for spinal cord injury (SCI), but clinical translation requires efficient differentiation into desired neural lineages and purification before transplantation. Here, differentiated hiPSCs-reprogrammed from human skin fibroblasts using Sendai virus-mediated expression of OCT4, SOX2, KLF4, and C-MYC-into neural rosettes expressing SOX1 and PAX6, followed by neuronal precursors (β-tubulin III⁺/NESTIN⁺) and glial precursors (GFAP⁺/NESTIN⁺). Both neuronal and glial precursors expressed the A2B5 surface antigen. A2B5+ NPCs, purified by fluorescence-activated cell sorting (FACS), proliferated in vitro with mitogens and differentiated into mature neurons and astrocytes under lineage-specific conditions. NOD-SCID mice received a T9 contusion injury followed by transplantation of A2B5+ NPCs, human fibroblasts, or control medium at 8 days post-injury. At two months, grafted NPCs showed robust survival, progressive neuronal maturation (β-tubulin III⁺ → doublecortin⁺ → NeuN⁺), and astrocytic differentiation (GFAP⁺), particularly in spared white matter. Transplantation significantly increased spared white matter volume and improved hindlimb locomotor recovery, with no teratoma formation observed. These results demonstrate that hiPSC-derived, FACS-purified A2B5+ NPCs can survive, differentiate into neurons and astrocytes, and enhance functional recovery after SCI. This approach offers a safe and effective candidate cell source for treating SCI and potentially other neurological disorders.

DOI: https://doi.org/10.1101/2025.08.12.669912
Stem Cell Res. 2025 Aug 09. pii: S1873-5061(25)00151-5. [Epub ahead of print]87 103801

Generation of three human induced pluripotent stem cell (hiPSC) lines from patients with Late-Onset Tay-Sachs disease (HEXA-related adult-onset GM2-gangliosidosis).

Gorka Fernández-Eulate, Céline Banal, Solène Renault, Nathalie Lefort, Yann Nadjar.

Late-Onset Tay-Sachs (LOTS) disease is caused by mutations in the HEXA gene associated with a deficiency in the lysosomal enzyme β-hexosaminidase A, ultimately leading to an accumulation of ganglioside GM2. Tay-Sachs disease presents with heterogeneous neurological manifestations depending on age at onset, LOTS being specifically characterized by spinal motor neuron (SMN) degeneration. The c.805G > A (p.Gly269Ser) mutation in the HEXA gene is the most frequent in patients with LOTS and associated with a higher residual activity. Nevertheless, the mechanisms underlying SMN degeneration are unknown, given that there is no relevant experimental model to study LOTS.

DOI: https://doi.org/10.1016/j.scr.2025.103801
Yi Chuan. 2025 Aug;47(8): 928-943

Biogenesis, action, function of plant small RNAs and their potential application in agriculture.

Huai-Hao Yang, Bing-Lian Zheng.

  Plant small RNAs (sRNAs) are essential regulators of gene expression and genome stability in plants. Based on their biogenesis and mechanisms of action, they are primarily classified into two major categories: microRNAs (miRNAs) and small interfering RNAs (siRNAs). These sRNAs rely on distinct processing proteins for their production and effector proteins to execute their functions, playing pivotal roles in diverse developmental processes and environmental responses. Recent advances in next-generation sequencing have identified numerous novel sRNAs across multiple plant species, while studies in Arabidopsis thaliana and various crops have significantly enhanced our understanding of their biogenesis, regulatory networks, and biological functions. In this review, we systematically summarize the research progress on different classes of plant sRNAs, focusing on their biosynthetic pathways, molecular mechanisms, and biological function. Furthermore, we discuss the potential applications of plant sRNAs in agriculture, including their prospects as next-generation RNA pesticides, supported by current technological developments. This review aims to provide a theoretical foundation for further research on plant sRNAs and their agricultural applications.

Keywords:  RNA pesticides; miRNA; phasiRNA; plant small RNA; siRNA

DOI:  https://doi.org/10.16288/j.yczz.25-163
Curr Protoc. 2025 Aug;5(8): e70199

Novel In Vitro Culture of Microglia from Aged Mice: Implications for the Future of Aging Neurobiology Research.

Katie L Reagin, Rae-Ling Lee, Kristen E Funk.

  Aging is associated with elevated levels of inflammation across tissues, a status recognized as "inflammaging." Within the brain, microglia are the resident phagocytic immune cells that are important in both homeostatic and disease states. Aged microglia are susceptible to processes of "inflammaging," which can include higher expression of baseline levels of inflammatory signals, decline in functional activity, and contribution to neurodegenerative processes. Information about microglial function has been gained using in vitro cell culture methods; however, most studies described previously have used microglia cultured from neonatal mice. More recent studies have used microglia cultured from young adult mice, but those using microglia from aged mice are lacking. Considering the distinct changes that come with aging and the important role of microglia in age-related neurologic disorders, there is a need for reliable protocols for studying aged cells specifically. Here, we describe a method to culture primary microglia from aged mice. Collected brain tissue is digested using enzymatic and mechanical techniques and then cultured in specific medium that supports the continued survival and proliferation of adult and aged microglia. To confirm microglial identity, cultured cells were immunostained for microglia-specific markers and imaged by microscopy and flow cytometry. We also compared the activation status of adult and aged microglia that were cultured versus those that were assessed directly after collection. Microglial cultures can easily be manipulated via genetic modifications or pharmacologic intervention to test specific functions. © 2025 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol: Culturing primary microglia from adult and aged mice.

Keywords:  aging; immunology; microglia; neuroscience; primary cell culture

DOI:  https://doi.org/10.1002/cpz1.70199
Nat Commun. 2025 Aug 18. 16(1): 7670

Transposable element expression and sub-cellular dynamics during hPSC differentiation to endoderm, mesoderm, and ectoderm lineages.

Isaac A Babarinde, Xiuling Fu, Gang Ma, Yuhao Li, Zhangting Liang, Jianfei Xu, Zhen Xiao, Yu Qiao, Zheng Lin, Katerina Oleynikova, Mobolaji T Akinwole, Xuemeng Zhou, Alexey Ruzov, Andrew P Hutchins.

Transposable elements (TEs) are genomic elements present in multiple copies in mammalian genomes. TEs were thought to have little functional relevance but recent studies report roles in biological processes, including embryonic development. To investigate the expression dynamics of TEs during human early development, we generated long-read sequence data from human pluripotent stem cells (hPSCs) in vitro differentiated to endoderm, mesoderm, and ectoderm lineages to construct lineage-specific transcriptome assemblies and accurately place TE sequences. Our analysis reveals that specific TE superfamilies exhibit distinct expression patterns. Notably, we observed TE switching, where the same family of TE is expressed in multiple cell types, but originates from different transcripts. Interestingly, TE-containing transcripts exhibit distinct levels of transcript stability and subcellular localization. Moreover, TE-containing transcripts increasingly associate with chromatin in germ layer cells compared to hPSCs. This study suggests that TEs contribute to human embryonic development through dynamic chromatin interactions.

DOI: https://doi.org/10.1038/s41467-025-63080-3
Brain. 2025 Aug 20. pii: awaf300. [Epub ahead of print]

Biallelic variants in COX18 cause a mitochondrial disorder primarily manifesting as peripheral neuropathy.

Camila Armirola-Ricaurte, Laura Morant, Isabelle Adant, Sherifa Ahmed Hamed, Menelaos Pipis, Stephanie Efthymiou, Silvia Amor-Barris, Derek Atkinson, Liedewei Van de Vondel, Aleksandra Tomic, Sara Seneca, Els de Vriendt, Stephan Zuchner, Bart Ghesquiere, Michael Hanna, Henry Houlden, Michael P Lunn, Mary M Reilly, Vedrana Milic Rasic, Albena Jordanova.

  Defects in mitochondrial dynamics are a common cause of Charcot-Marie-Tooth disease (CMT), while primary deficiencies in the mitochondrial respiratory chain (MRC) are rare and atypical for this etiology. This study aims to report COX18 as a novel CMT-causing gene. This gene encodes an assembly factor of mitochondrial Complex IV (CIV) that translocates the C-terminal tail of MTCO2 across the mitochondrial inner membrane. Exome sequencing was performed in four affected individuals from three families. The patients and available family members underwent thorough neurological and electrophysiological assessment. The impact of one of the identified variants on splicing, protein levels, and mitochondrial bioenergetics was investigated in patient-derived lymphoblasts. The functionality of the mutant protein was assessed using a Proteinase K protection assay and immunoblotting. Neuronal relevance of COX18 was assessed in a Drosophila melanogaster knockdown model. Exome sequencing coupled with homozygosity mapping revealed a homozygous splice variant c.435-6A>G in COX18 in two siblings with early-onset progressive axonal sensory-motor peripheral neuropathy. By querying external databases, we identified two additional families with rare deleterious biallelic variants in COX18. All eight affected individuals presented with axonal CMT and some patients also exhibited central nervous system symptoms, such as dystonia and spasticity. Functional characterization of the c.435-6A>G variant demonstrated that it leads to the expression of an alternative transcript that lacks exon 2, resulting in a stable but defective COX18 isoform. The mutant protein impairs CIV assembly and activity, leading to a reduction in mitochondrial membrane potential. Downregulation of the COX18 homolog in Drosophila melanogaster displayed signs of neurodegeneration, including locomotor deficit and progressive axonal degeneration of sensory neurons. Our study presents genetic and functional evidence that supports COX18 as a newly identified gene candidate for autosomal recessive axonal CMT with or without central nervous system involvement. These findings emphasize the significance of peripheral neuropathy within the spectrum of primary mitochondrial disorders and the role of mitochondrial CIV in the development of CMT. Our research has important implications for the diagnostic workup of CMT patients.

Keywords:  CMT; complex IV deficiency; cytochrome c oxidase assembly factor 18

DOI:  https://doi.org/10.1093/brain/awaf300
Sci Rep. 2025 Aug 19. 15(1): 30295

Sevoflurane inhibition of the developmentally expressed neuronal sodium channel Nav1.3.

Jiaxin Xiang, Karl F Herold, Jimcy Platholi, Hugh C Hemmings.

  Neuronal voltage-gated sodium channels (Nav) are major targets for the neurophysiological actions of general anesthetics. In the adult brain, cell type-specific effects on synaptic transmission are attributed to the differential sensitivity to volatile anesthetics of specific Nav subtypes preferentially expressed in mature neurons (Nav1.1, Nav1.2, Nav1.6). Comparatively, developing neurons are more excitable than mature neurons. We determined volatile anesthetic effects on Na+ currents mediated by Nav1.3, the principal Nav subtype expressed in developing neurons. Sevoflurane at clinical concentrations inhibited peak Na+ current of human Nav1.3 heterologously expressed in HEK293T cells in a voltage-dependent manner, induced a - 6.1 mV hyperpolarizing shift in the voltage dependence of steady-state inactivation, and slowed recovery from fast inactivation. Nav1.3-mediated Na+ currents also exhibited distinct activation properties associated with hyperexcitability, including prominent persistent currents and ramp currents, both of which were significantly reduced by sevoflurane. Nav1.3 showed a more depolarized voltage dependence of steady-state inactivation than Nav1.2, consistent with its higher propensity for sustained repetitive firing. Nav1.2 exhibited minimal persistent and ramp currents, and these were unaffected by sevoflurane. These findings identify subtype-specific effects of sevoflurane on neuronal Nav subtype electrophysiological properties, and suggest a mechanistic basis for increased anesthetic sensitivity and toxicity in early neuronal differentiation and maturation.

Keywords:  Anesthetic mechanism; Persistent current; Ramp current; Volatile anesthetic; Voltage-gated sodium channel

DOI:  https://doi.org/10.1038/s41598-025-15280-6
APL Bioeng. 2025 Sep;9(3): 036111

A modular and reconfigurable microfluidic device for culturing spheroids under continuous perfusion.

Hiba Aljayyousi, Sarah Sahloul, Ajymurat Orozaliev, Navajit Baban, Anh-Duc Van, Amani Al Nuairi, Pauline John, Azhar Zam, Piergiorgio Percipalle, Yong-Ak Song.

3D cell spheroids have become crucial in vitro models for biomedical research, yet maintaining their growth and viability remains challenging due to diffusion limitations. We developed a versatile microfluidic modular device with a reconfigurable channel design that is customizable by altering the channel configuration in the adhesive layer. The resealable adhesive layer also enables open access to the wells for loading cells, continuous perfusion after closing, and facile retrieval of spheroids for downstream analysis and imaging after culturing. We evaluated three channel configurations using Mouse Embryonic Fibroblasts (MEFs), human induced Pluripotent Stem Cells (hiPSCs), and MDA-MB-231 breast cancer cells. The device significantly improved spheroid growth in MEFs and hiPSCs, increasing up to 139.9% over controls in 14 days. In contrast, MDA-MB-231 spheroids exhibited slower growth, highlighting the need for balancing nutrient delivery with autocrine factor retention. Sphericity was maintained in MEF and MDA-MB-231 spheroids, while hiPSC spheroids experienced budding. In situ optical coherence tomography (OCT) provided noninvasive 3D viability assessments of the spheroids. Our findings demonstrate that this modular microfluidic device, combined with OCT analysis, offers a powerful platform for advancing spheroid culture techniques and opens up new opportunities in applications such as drug testing, studying spheroid-spheroid interactions, and collecting spheroid secretions.

DOI: https://doi.org/10.1063/5.0262536
Glia. 2025 Aug 19.

Astrocyte Secretome Profiling via Biorthogonal Labeling Unveils Novel Factors Relevant to Neurodegenerative Diseases.

Jie Liu, Jing Gao, Lin Guo, Guoming Ma, Mingfeng Guan, Congcong Xia, Jia He, Yufang Yang, Yi Wu, Jun Xu, Liulin Xiong, Chang-Yin Yu, Gang Pei, Jian Zhao, Jianchen He, Yaoyang Zhang, Wenyuan Wang.

  Secreted proteins are key mediators of intercellular communication in multicellular organisms. However, progress in secretomics has been hindered by the lack of effective methods for capturing secreted proteins. Here, we present a two-step secretome enrichment method (tsSEM) that integrates unnatural amino acid labeling with click chemistry-based biorthogonal reaction, enabling robust in vitro secretome profiling in the presence of serum. Applying tsSEM, we systematically analyzed the secretome of human induced pluripotent stem cells (iPSCs)-derived astrocytes (iAst) across various disease models and identified a panel of astrocyte-secreted proteins contributing to noncell autonomous neurotoxicity. Among these, we validated two novel neurotrophic factors, FAM3C and KITLG, which enhanced neurite outgrowth, protected neuronal viability, and promoted neural progenitor proliferation. Our findings demonstrate the utility of tsSEM for high-resolution secretome analysis and underscore the potential of iAst-derived secretomes in elucidating disease mechanisms and identifying therapeutic targets.

Keywords:  astrocyte; click chemistry; neurological disorders; noncell autonomous toxicity; secretome

DOI:  https://doi.org/10.1002/glia.70079
bioRxiv. 2025 Aug 12. pii: 2025.08.09.669485. [Epub ahead of print]

Specific Combinations of Physiological Tau Phosphorylation Regulate Tau-Microtubule Interactions in Developing Neurons.

Nima N Naseri, Tian Xu, Sapanna Chantarawong, Steven M Patrie, Neil L Kelleher, Manu Sharma, Ophir Shalem, Elizabeth Rhoades.

Tau phosphorylation is a defining feature of Alzheimer's disease, yet it also plays an essential physiological role in stabilizing microtubules (MTs) during normal neuronal development. While individual phosphorylation sites have been well-studied in pathology, it remains largely unknown how combinatorial phosphorylation is regulated under physiological conditions. Here, we uncover distinct, site-specific phosphorylation patterns on tau in developing human neurons. With top-down mass spectrometry we find that functional, endogenous tau is highly modified, with up to 21 phosphates per molecule. We identify patterns of co-occurrence between phosphorylation sites that are in proximity in the linear protein sequence, such as epitopes S202/T205/T212/T217 and T231/S235/S262. Moreover, these phospho-epitopes define discrete pools of tau and regulate tau-MT interactions in coordination, providing a mechanism for fine-tuning the binding of tau to MTs. Intriguingly, we find that co-occurring phospho-epitopes are dynamically regulated in response to changes in MT integrity; chemical perturbation of neuronal MTs promotes rapid tau dephosphorylation by phosphatase PP2a at most sites to enhance tau-MT interactions and counteract destabilization. We then use the PS19 tauopathy mouse model to demonstrate that developmental and pathological tau phosphorylation patterns partially overlap, and that co-occurring phospho-epitopes exhibit similar associations with the insoluble fraction in aged mice. Our results reveal an isoform-dependence on the effects of site-specific tau phosphorylation on its behavior. Together, these findings define a combinatorial phosphorylation code that modulates tau's physiological function in neurons and raises the possibility that MT destabilization precedes tau phosphorylation in disease. This work provides a mechanistic framework for distinguishing functional from pathological tau phosphorylation, with implications for the development of therapies that specifically target disease-associated tau proteoforms.

DOI: https://doi.org/10.1101/2025.08.09.669485
bioRxiv. 2025 Aug 11. pii: 2025.08.09.669489. [Epub ahead of print]

Centrosomal P4.1-associated protein (CPAP) is a novel regulator of ESCRT pathway function during multivesicular body formation and endosome maturation.

Radhika Gudi, Chenthamarakshan Vasu.

Previously, we have shown that Centrosomal P4.1-associated protein (CPAP) is a positive regulator of endocytic vesicle transport (EVT) pathway, and it promotes lysosomal targeting of ligand-bound EGFR. Here, we show that recruitment of TSG101, an ESCRT-I protein, to endosome is the mechanism by which CPAP facilitates EVT. While CPAP depletion disrupts the Rab5-to-Rab7 conversion and endosome maturation processes, it does not interact with these GTPases. We found that CPAP not only co-immunoprecipitates with TSG101, but also colocalizes with TSG101 as well as ESCRT 0 protein HRS on the early endosomes. Although CPAP-TSG101 interaction occurs under quiescent state, this interaction is more robust during EVT progression. TSG101 recruitment to endosome and Rab5-to-Rab7 conversion were restored in CPAP depleted cells upon overexpression of HRS suggesting that CPAP functions upstream of TSG101, but in parallel to HRS, and bridges ESCRT 0 and ESCRT I components. Our results reveal a novel ESCRT dependent regulatory role for the centriole biogenesis protein CPAP in endosome maturation.
Teaser: Microcephaly-associated protein CPAP recruits TSG101 to the endosome and facilitates ESCRT function and endosome maturation.

DOI: https://doi.org/10.1101/2025.08.09.669489
bioRxiv. 2025 Aug 15. pii: 2025.08.12.669858. [Epub ahead of print]

Circular continuum of alpha motoneuron types.

Teresa L Garrett, Lee Wintermute, Maggie Armitage, Shelby Ward, Ibrahim Abdul Halim, Mohamed H Mousa, Kalin Gerber, Sherif M Elbasiouny.

Alpha-motoneurons (α-MNs) are traditionally classified into slow (S), fast fatigue-resistant (FR), and fast-fatigable (FF), which exist along a continuum of properties between slow and fast, enabling the generation of graded force and seamless movement. Using combinations of markers, we developed novel immunohistochemistry protocols that enabled co-labeling of six major and transitional α-MN types throughout the mouse lumbar spinal cord with unprecedented detail. Intriguingly, our protocols labeled for the first time: α-MNs of the fast fatigue intermediate (FI) type; a previously undescribed transitional α-MN subtype (FR/FI); and a novel subtype of α-MNs exhibiting hybrid characteristics of both S and FF types - termed S/FF - which resist ALS degeneration. Electrophysiological recordings confirmed FR/FI and S/FF subtypes, both exhibiting mixed traits. The discovery of S/FF subtype reveals that α-MNs exist along a circular continuum between slow and fast types, challenging the traditional linear model and reshaping our understanding of their role in motor control.
Significance Statement: This work is significant in three major ways: Technical innovation : We introduce a novel immunohistochemistry protocol capable of co-labeling six distinct and transitional α-MN types in the adult spinal cord. This tool will be highly valuable for the broader neuroscience community. Conceptual breakthrough : The discovery of a circular rather than linear continuum of α-MN types represents a paradigm shift in our understanding of α-MN organization and their role in motor control. Relevance to disease : The distinct susceptibilities of α-MN subtypes to degeneration - particularly in aging and ALS - highlight the importance of this new framework in studying neurodegenerative diseases. Our protocol enables this research with new levels of precision and rigor. In summary, this study has broad implications for understanding motor control in both healthy and diseased states.

DOI: https://doi.org/10.1101/2025.08.12.669858
Cell Rep. 2025 Aug 14. pii: S2211-1247(25)00924-6. [Epub ahead of print]44(8): 116153

From thought to action: The organization of spinal projecting neurons.

Carla C Winter, Kuan Hong Wang, Zhigang He.

  Spinal projecting neurons (SPNs) are specialized neurons with cell bodies residing in the brain and axons extending into the spinal cord, providing a direct communication pathway that enables top-down control of nearly every bodily function. Disruptions to these pathways contribute to a wide range of neurological disorders, including developmental, degenerative, and traumatic pathologies. Advances in retrograde labeling, activity monitoring, and circuit manipulation have enabled increasingly precise and comprehensive characterizations of SPNs. Here, we provide a historical overview of brain-spinal cord connectivity research, followed by an in-depth synthesis of the current knowledge of SPN anatomical connections, molecular identities, and functional properties. We then propose a conceptual framework in which distinct SPN modules coordinately regulate motor, autonomic, and sensory processes to support bodily readiness and drive behavioral action. Beyond revealing the organizational logic of SPNs, these insights provide a foundation for designing therapies to restore brain-spinal cord communication following injury or disease.

Keywords:  CP: Neuroscience; descending control; spinal cord; spinal cord injury

DOI:  https://doi.org/10.1016/j.celrep.2025.116153
J Huntingtons Dis. 2025 Aug 19. 18796397251366891

Abnormal neurodevelopment predisposes to cortical hyperexcitability in Huntington's disease.

Carlos Cepeda, Joshua Barry, Sandra M Holley.

  Accumulating morphological and electrophysiological evidence demonstrates that abnormal brain development is a key element in the progression of Huntington's disease (HD). Mutant huntingtin affects corticogenesis, cell migration, and differentiation. Cortical changes are reminiscent of focal cortical dysplasia, a malformation of cortical development that leads to hyperexcitability and epilepsy. Striatal development also is affected by the mutation. In animal models, recent studies provide additional evidence that neuronal morphology and intrinsic and electrophysiological properties deviate from normal development. Some changes indicate delayed development of cortical pyramidal neurons, while a subtype of striatal projection neuron displays a transient accelerated maturation. However, the brain is able to compensate for early abnormalities and, during a variable latent period, brain function appears normal. Eventually, homeostatic mechanisms begin to fail, resulting in the emergence of HD symptoms. The realization that neurodevelopment in HD is abnormal offers new insights and opens new avenues for early treatment. In this review, we present a brief summary of imaging and morphological studies from human carriers of the HD mutation followed by a more in-depth examination of recent findings in genetic animal models.

Keywords:  NeuN/RBFOX3; electrophysiology; focal cortical dysplasia; hyperexcitability; neurodevelopment; striatum

DOI:  https://doi.org/10.1177/18796397251366891
Biophys J. 2025 Aug 18. pii: S0006-3495(25)00529-6. [Epub ahead of print]

Vesicle tension in porous membranes: aspiration, spreading, and tube extraction.

Grégory Beaune, Françoise Brochard-Wyart.

We review recent theoretical and experimental advances in understanding the mechanical tension of porous vesicles. Focusing on three key deformation processes, aspiration, spreading, and tube extrusion, we show how membrane porosity introduces novel timescales and feedback mechanisms that alter vesicle behavior. In particular, we highlight how tube extrusion from porous membranes demonstrates the vesicle's ability to regulate internal volume and dynamically modulate membrane tension. This regulation enables the sustained elongation of membrane tubes under milder mechanical conditions than those required for non-porous vesicles. These findings provide new insight into biologically relevant processes such as organelle shaping, intracellular transport, and mechanosensitive remodeling, emphasizing the crucial role of membrane permeability in cellular morphodynamics.

DOI: https://doi.org/10.1016/j.bpj.2025.08.017
bioRxiv. 2025 Aug 12. pii: 2025.08.10.669191. [Epub ahead of print]

The mevalonate pathway couples lipid metabolism to amino acid synthesis via ubiquinone-dependent redox control.

Thi Thinh Nguyen, Mohit Bansal, Jane Ding, Sunil Sudarshan, Han-Fei Ding.

The mevalonate pathway produces sterols and isoprenoids that support cancer cell growth, yet its broader metabolic functions remain incompletely defined. Here, we show that this pathway sustains amino acid biosynthesis by promoting mitochondrial NAD⁺ regeneration through ubiquinone-dependent electron transport. Statin-mediated inhibition of the mevalonate pathway impairs oxidative phosphorylation, lowers the NAD⁺/NADH ratio, and suppresses de novo serine and aspartate synthesis, thereby activating the GCN2-eIF2α-ATF4 amino acid deprivation response. The resulting depletion of serine-derived glycine and one-carbon units, together with reduced aspartate availability, limits purine and pyrimidine nucleotide production. Expression of the bacterial NADH oxidase LbNOX or the alternative oxidase AOX restores NAD⁺ levels and rescues statin-induced growth inhibition. These findings suggest that impaired NAD⁺ regeneration is a key mechanism contributing to the anti-proliferative activity of statins, linking the mevalonate pathway to mitochondrial electron transport- dependent control of amino acid metabolism.
Significance: This study identifies the mevalonate pathway as a regulator of amino acid biosynthesis through mitochondrial electron transport-dependent NAD⁺ regeneration and reveals redox disruption as a key mechanism contributing to the anti-proliferative effects of statins.

DOI: https://doi.org/10.1101/2025.08.10.669191
Autophagy. 2025 Aug 16.

Inhibition of UBE2N promotes the clearance of mutant HTT (huntingtin) in HD knock-in mice.

Kaili Ou, Xiang Wang, Mingwei Guo, Dandan Li, Chen Zhang, Laiqiang Chen, Junqi Hou, Qingqing Jia, Longhong Zhu, Su Yang, Shihua Li, Xiao-Jiang Li, Peng Yin.

  Accumulation of misfolded proteins leads to many neurodegenerative diseases that can be treated by lowering or removing mutant proteins. Huntington disease (HD) is characterized by the accumulation of ubiquitinated mutant HTT (huntingtin) in the central nervous system. Ubiquitination of the misfolded proteins, a common feature of the neurodegenerative diseases, is mediated by the different lysine residues on ubiquitin. We previously discovered that the age-dependent increase of UBE2N (ubiquitin conjugating enzyme E2 N) exacerbated the accumulation of misfolded HTT and amyloid proteins, accompanied by the elevation of K63 ubiquitination. Pharmacological inhibition of UBE2N could ameliorate the amyloid deposition. However, the effect of UBE2N suppression on HTT aggregate clearance has remained unknown. In the current work, we demonstrate that selectively suppressing UBE2N, with antisense oligonucleotides or small-molecular inhibitors, increased removal of HTT aggregates by proteasome degradation in the striatum of HD knock-in mice. We also identified two novel ubiquitin specific peptidases, USP29 and USP49, that participated in the clearance of HTT aggregates, via accelerating K48-mediated ubiquitin-proteasome function. Our findings provide a potential pharmacological approach to treat neurodegeneration caused by mutant HTT.

Keywords:  Aggregate; HTT; K63; UBE2N; UPS; ubiquitin specific peptidases

DOI:  https://doi.org/10.1080/15548627.2025.2549109
Struct Dyn. 2025 Jul;12(4): 044701

Molecular chameleons adaptability in target binding.

Guanhong Bu, Måns Eriksson, Emma Rova Danelius.

Estimates show that up to 85% of the human therapeutic proteomes are undruggable by traditional small molecules. Macrocycles, a class of molecular leads, often extend beyond the traditional drug space and offer the potential to modulate challenging targets within this 85%. These modalities exhibit significant conformational flexibility and often function as molecular chameleons, enabling them to adapt to environments with varying polarities while ensuring good oral bioavailability. In this study, we explore the conformational adaptability in target binding of the three known molecular chameleons, paritaprevir, grazoprevir, and simeprevir, by docking their experimental crystal structures, solution conformations, and target-bound structures into multiple protein targets, including human drug transporters associated with drug-drug interactions and COVID-19 related proteins. Our findings reveal that the macrocyclic core conformational class, or "chameleonic group," determines the overall pharmacophore conformations and influences the conformational changes required for binding to various proteins. These insights provide a pathway toward rationalizing drug optimizations for molecular chameleons as well as offering specific guidance for improving Hepatitis C virus nonstructural protein 3/4A inhibitors, including providing a starting point for their COVID-19 repurposing and cancer therapy.

DOI: https://doi.org/10.1063/4.0000757
Angew Chem Int Ed Engl. 2025 Aug 19. e202512415

Predictable Modulation of a Spontaneous Post-translational Modification in Living Cells.

Meghan S Martin, Nomindari Bayaraa, Brittany T Fox, Yu-Shan Lin, Rebecca A Scheck.

  Glycation is a nonenzymatic posttranslational modification associated with aging and disease. Because it occurs spontaneously, it is extremely difficult to control the extent of glycation at distinct sites within target proteins, especially in cellular systems. Here, we report a chemical approach, referred to as "dialAGE", that enables the site-specific control of protein glycation. This unique tool requires the introduction of just a single point mutation that modulates the glycation susceptibility of a nearby arginine. As proof-of-concept, extensive mass spectrometry analysis was performed to confirm that dialAGE can modulate site-specific glycation levels at multiple arginine residues in ubiquitin in vitro, enabling both enhanced and diminished glycation. Introduction of dialAGE point mutations and/or glycation with the biologically relevant glycating agent methylglyoxal did not affect polyubiquitin chain formation using in vitro ubiquitination assays. Furthermore, we show that dialAGE can be used to modulate ubiquitin glycation levels in living mammalian cells. We, therefore, anticipate that this method will be particularly useful for enabling the study of glycation as a genuine, functional, and posttranslational modification.

Keywords:  Advanced‐glycation end product; Chemoselectivity; Glycation; Methylglyoxal; Protein modifications

DOI:  https://doi.org/10.1002/anie.202512415