bims-axbals Biomed News
on Axonal biology and ALS
Issue of 2026–06–28
twenty-two papers selected by
TJ Krzystek



  1. Proc Natl Acad Sci U S A. 2026 Jun 30. 123(26): e2610001123
      Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are progressive neurodegenerative disorders characterized by motor neuron degeneration, leading to muscle weakness, atrophy, and cognitive impairments. A defining pathological hallmark of ALS/FTD is the cytosolic mislocalization and accumulation of TAR DNA-binding protein 43 (TDP-43), highlighting its critical role in ALS pathogenesis. However, the molecular mechanisms underlying TDP-43 proteostasis remain poorly understood. Through a genetic screening approach, we identify inositol-requiring enzyme 1 (IRE1), an endoplasmic reticulum-resident transmembrane protein, as a potent suppressor of TDP-43 protein levels. Furthermore, we show that ribosome-associated quality control (RQC) factors play a crucial role in regulating TDP-43 proteostasis and cellular toxicity. Activation of the RQC pathway prevents excessive accumulation of TDP-43 and associated toxicity. Mechanistically, our findings suggest that IRE1 regulates TDP-43 protein level by promoting the degradation of aberrant TDP-43 translation product through the RQC pathway. IRE1 acts canonically to enhance the transcription of the RQC core component Clbn/NEMF and noncanonically to physically interact with Clbn/NEMF, thereby ameliorating TDP-43-induced proteotoxicity. Moreover, ectopic expression or pharmacological activation of IRE1 alleviates TDP-43 pathology and restores cognitive function in the TDP-43 A315T ALS mouse models. Collectively, our study identifies a role for IRE1 in the translational quality control of TDP-43 and establishes its potential as a therapeutic target for ALS/FTD.
    Keywords:  IRE1; TDP-43/TARDBP; ribosome-associated quality control (RQC)
    DOI:  https://doi.org/10.1073/pnas.2610001123
  2. Brain. 2026 Jun 25. pii: awag222. [Epub ahead of print]
      STMN2 is an abundant neurospecific protein dysregulated in neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS). We previously reported that cellular stress can lead to STMN2 loss due to TDP-43 nuclear condensation. Here, using human and murine neuronal cell models, multiple pharmacological tools, in situ single-molecule analysis of translation and RNA localisation, and longitudinal analysis of neuronal fitness/survival, we establish TDP-43-independent mechanisms of STMN2 depletion under stress. We find that human STMN2 protein level is extremely labile under acute high-magnitude stress. Early in stress, STMN2 is suppressed via activated proteasomal degradation, phosphorylation and translation repression by stress granules, independently of TDP-43 loss of function in splicing. We further show that STMN2 protein level is highly sensitive to chronic translation deficits, such as those elicited by prolonged low-grade stress. We find that low pre-stress STMN2 sensitises neuronal cells to stress-induced apoptosis, whereas moderately increased STMN2 is protective under stress. Finally, we demonstrate that STMN2 mRNA is upregulated in non-TDP ALS (ALS-FUS) models, which may compensate for translation/stress granule defects in this disease subtype. Consistent with the compensation hypothesis, STMN2 mRNA is also upregulated in the relatively spared (cortex), but not severely affected (spinal cord), CNS regions in ALS-TDP. In conclusion, our study implicates two common denominators in neurodegeneration - dysregulation of translation and stress granules - in STMN2 depletion, independent of TDP-43 loss of function. It also describes an RNA-based compensatory mechanism in ALS underling the unique vulnerability of neurons with developing TDP-43 pathology.
    Keywords:  ALS; FUS; STMN2; TDP-43; protein translation; stress granule
    DOI:  https://doi.org/10.1093/brain/awag222
  3. Sci Adv. 2026 Jun 26. 12(26): eady0256
      Prion-like domain (PrLD)-mediated aggregation and concomitant dysfunction of the essential RNA-binding protein transactive response (TAR) DNA-binding protein of 43 kilodaltons (TDP-43) is a common feature of multiple debilitating neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS). However, shortened TDP-43 (sTDP-43) splice isoforms where the PrLD is largely replaced by an 18-residue carboxyl-terminal tail also contribute to ALS pathophysiology and are enriched in motor neurons. Curiously, despite lacking most of the PrLD, sTDP-43 exhibits pronounced insolubility in cells and tissue of patients with ALS. Here, we establish that the short, isoform-specific carboxyl-terminal tail of sTDP-43 confers high aggregation propensity, which is encoded by two clusters of steric zippers, and can be mitigated by short RNA chaperones. Disrupting these zippers enhances sTDP-43 solubility at the pure protein level and in neurons. Notably, these steric zippers, rather than a predicted nuclear export signal in the carboxyl-terminal tail, drive cytoplasmic mislocalization and aggregation of sTDP-43 in neurons. Thus, we define the sequence-encoded determinants of aberrant sTDP-43 assembly and provide mechanistic insights into sTDP-43 disease pathology.
    DOI:  https://doi.org/10.1126/sciadv.ady0256
  4. Biomolecules. 2026 Jun 17. pii: 893. [Epub ahead of print]16(6):
      Amyotrophic lateral sclerosis (ALS) remains an intractable motor neuron (MN) disease with a growing patient population and few effective treatments. Here, we review how extracellular phosphoglycerate kinase 1 (ePgk1) improves neurite outgrowth of MNs (NOMN) and axonal growth, both in vitro and in vivo. Our group first elucidated a novel non-canonical function of ePgk1 as a cross-tissue mediator between nerve and muscle tissues. We then discovered that neural membranous Enolase 2 (Eno2) serves as a receptor of ligand ePgk1 and that ePgk1-Eno2 interaction suppresses the Rac1-GTP/p-Pak1-T423/p-P38-T180/pMK2-T334/p-Limk1-S323 axis, reducing p-Cofilin and promoting NOMN and axonal growth, finally suggesting that the 419th aspartic acid residue of Eno2 mediates this interaction. In a crucial preclinical step, we truncated two short 16-amino-acid derivatives from Pgk1, FD-1/-2, each mediating neuroprotection comparable to that of full-length 417-amino-acid Pgk1 in ALS animal models, in terms of improvements of innervated neuromuscular junction, MN cell bodies, motor performance, and endpoint prolongation. In this context, we also discuss the opposite function driven by Eno1-plasminogen interaction and by Eno2-ePgk1 interaction; the latter results in unfavorable for tumorigenesis. Unlike intracellular Pgk1 roles, ePgk1 is an extracellular factor with anti-angiogenic properties, further positioning ePgk1 and its FD-1/-2 as promising protein/peptide drugs for ALS treatment.
    Keywords:  amyotrophic lateral sclerosis; enolase; motor neuron; neurodegeneration; phosphoglycerate kinase; therapeutic peptide
    DOI:  https://doi.org/10.3390/biom16060893
  5. J Neurodev Disord. 2026 Jun 26.
      With the advent of exome sequencing, a growing number of children are being identified with de novo loss-of-function mutations in the dynamin 1-like (DNM1L) gene, which encodes the large GTPase essential for mitochondrial fission, dynamin-related protein 1 (DRP1). Mutations in DRP1 result in severe neurodevelopmental phenotypes, such as developmental delay, optic atrophy, and epileptic encephalopathies. Though it is established that mitochondrial fission is an essential precursor to the rapidly changing metabolic needs of the developing cortex, it is not understood how identified mutations in different domains of DRP1 uniquely disrupt cortical development and synaptic maturation. We leveraged the power of human induced pluripotent stem cells (iPSCs) harboring DRP1 mutations in either the GTPase or stalk domains to model early stages of cortical development in vitro. High-resolution time-lapse imaging of transport in neuronal projections revealed mutation-specific changes in mitochondrial motility of severely hyperfused mitochondrial structures. Transcriptional profiling of mutant DRP1 cortical neurons during maturation also implicated mutation-dependent alterations in synaptic development and gene expression of calcium-regulatory genes. Disruptions in calcium dynamics were confirmed using live functional recordings of 65-200 days in vitro (DIV) mutant DRP1 cortical neurons. These findings strongly suggest that altered mitochondrial morphology in DRP1 mutant neurons leads to pathogenic dysregulation of synaptic development and activity.
    Keywords:  DRP1; Mitochondria; Mitochondrial fission; Neurons
    DOI:  https://doi.org/10.1186/s11689-026-09713-0
  6. Expert Opin Drug Discov. 2026 Jun 23. 1-8
       INTRODUCTION: ALS drug discovery has long depended on model systems that incompletely capture human disease heterogeneity, aging, and TDP-43 proteinopathy. Patient-derived platforms have therefore emerged as increasingly important human-relevant complements to animal and molecular models.
    AREAS COVERED: This Critical Perspective examines when patient-derived ALS models genuinely change therapeutic decision-making rather than merely add mechanistic insight. The authors then propose a heuristic framework based on disease-relevant phenotype recapitulation, capture of patient-to-patient heterogeneity, and generation of findings that influence therapeutic prioritization or clinical translation. Furthermore, the authors evaluate iPSC-derived motor neurons, directly reprogrammed neurons, glial co-cultures, organoids, neural networks, and organ-chip systems against these conditions, while also addressing aging fidelity, reproducibility, upper motor neuron modeling, and regulatory implementation.
    EXPERT OPINION: Patient-derived models are not yet standalone decision-grade tools for ALS drug development. Their present value lies in functioning as a human-biology filter for target discovery, reverse translation, biomarker development, and patient stratification when used within rigorous, standardized, and clinically linked workflows. The strongest current evidence supports proof-of-principle rather than generalized predictive validity.
    Keywords:  Amyotrophic lateral sclerosis; assembloid; drug discovery; induced pluripotent stem cells; organ-on-chip; precision medicine; reverse translation
    DOI:  https://doi.org/10.1080/17460441.2026.2689746
  7. bioRxiv. 2026 Jun 10. pii: 2026.06.09.731146. [Epub ahead of print]
      Lysosomal membrane damage triggers a multi-stage repair response essential for cellular homeostasis. Here we identify the oxysterol-binding protein-related protein ORP3 as a critical mediator of late-stage lysosomal membrane repair. Following lysosomal damage induced by L-leucine-leucine methyl ester (LLOME) or cationic amphiphilic drugs (CADs), ORP3 is phosphorylated and recruited to ER-lysophagosome contact sites via a signaling cascade initiated by lysosomal membrane ubiquitination, TAK1, p38 MAPK, and, to a lesser extent, IKK. p38-dependent phosphorylation promotes direct interaction between ORP3 and LC3B, which together with PI(4,5)P₂ binding, is required for autophagic lysosome recruitment. ORP3 depletion impairs late-stage lysosomal recovery, elevates lysosomal lipid peroxidation, and reduces cell survival. A lipid transfer-deficient ORP3 mutant fails to restore lysosome function despite normal recruitment, indicating that ER-to-lysophagosome transfer of phosphatidylcholine by ORP3 is functionally required. ORP3 activity is subsequently terminated by VCP/p97-mediated deubiquitination of lysosomes. These findings define ORP3 as a MAPK regulated lipid transfer protein during the late autophagic phase of the endolysosomal damage response.
    Summary: Lysosomal membrane damage triggers ubiquitination that activates a TAK1-p38 signaling cascade, phosphorylating the lipid transfer protein ORP3 and recruiting it to damaged lysosomes via LC3B interaction. ORP3-mediated phosphatidylcholine transfer from the ER is essential for late-stage lysosomal repair and cell survival.
    Abstract Figure:
    DOI:  https://doi.org/10.64898/2026.06.09.731146
  8. Acta Neuropathol Commun. 2026 Jun 26.
      Extracellular vesicles (EVs) are heterogenous lipid bilayer-enclosed particles secreted by virtually all cell types. They encapsulate a diverse array of bioactive molecules, including proteins, lipids, nucleic acids, and metabolites, which can be transferred to recipient cells, thereby modulating their function and phenotype. In recent years, skeletal muscle-derived EVs (SkM-EVs) have emerged as key players in the bidirectional communication between skeletal muscle and motor neurons, contributing to the establishment and maintenance of neuromuscular homeostasis. Disruptions in this intercellular signalling have been implicated in the pathophysiology of motor neuron diseases (MNDs) such as spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS). In these contexts, SkM-EVs may contribute to disease progression by delivering pathogenic cargo, including misfolded proteins and aberrant RNAs, to motor neurons. A comprehensive understanding of SkM-EV biology, particularly their roles in neuromuscular communication, could offer critical insights into disease mechanisms and identify novel opportunities for biomarker discovery and therapeutic intervention. This review synthesizes current knowledge on the functional roles of SkM-EVs in motor neuron health and disease and evaluates their potential as diagnostic tools and therapeutic vectors in the context of MNDs.
    Keywords:  ALS; Extracellular vesicles; Motor neuron; Neurodegenerative diseases; SMA
    DOI:  https://doi.org/10.1186/s40478-026-02356-1
  9. Stem Cell Reports. 2026 Jun 25. pii: S2213-6711(26)00187-6. [Epub ahead of print] 102976
      Drug screening for genetic disorders is limited by difficulty identifying disease-relevant phenotypes. In this issue, Roussange et al., show that reverse phenotypic mapping could uncover therapeutic gene expression signatures. Using this approach, they identified prazosin, which increases SQSTM1 expression and rescues disease phenotypes in iPSC-derived motor neurons and zebrafish model of amyotrophic lateral sclerosis with SQSTM1 haploinsufficiency.
    DOI:  https://doi.org/10.1016/j.stemcr.2026.102976
  10. Dev Cell. 2026 Jun 25. pii: S1534-5807(26)00198-X. [Epub ahead of print]
      Maintenance of plasma membrane integrity is essential for compartmentalization of the cytosol and for cellular viability. Upon membrane damage, several factors including endosomal sorting complex required for transport-III (ESCRT-III) proteins, annexins, stress granules, lipids, and membrane fusion proteins are mobilized to orchestrate membrane repair. However, whether these factors operate independently or act together is unclear. Here, using human cell lines, we expose temporal differences and interdependencies in the recruitment of ESCRT-III and annexin proteins to sites of plasma membrane damage. We show that annexin proteins are recruited immediately and form a plug at the damage site, restricting membrane permeability. We find that ESCRT-III assembles later and acts to release plug-containing damaged membranes from the cell. Further, frontotemporal dementia (FTD)- and amyotrophic lateral sclerosis (ALS)-associated mutations in the ESCRT-III protein, CHMP2B, and the annexin protein, ANXA11, compromise plasma membrane repair, suggesting that defects in this process may contribute to these pathologies. These data present an integrated "sealing and healing" model of membrane repair.
    Keywords:  ALS; ANXA11; CHMP2B; ESCRT-III; FTD; annexin; membrane repair; pore-forming toxin
    DOI:  https://doi.org/10.1016/j.devcel.2026.05.014
  11. J Neurosci Methods. 2026 Jun 23. pii: S0165-0270(26)00167-6. [Epub ahead of print]434 110837
       BACKGROUND: Genetic and acquired forms of small fiber neuropathies lead to debilitating health conditions, resulting in pain or loss of sensation. These neuropathies are caused by dysfunction or degeneration of unmyelinated peripheral sensory axons: c fibers. Rodent models have been used to investigate molecular mechanisms leading to neuropathies and search for potential therapeutic targets. Although these studies have advanced our understanding of small fiber neuropathies, rodent studies don't fully recapitulate human diseases. Sensory neurons derived from human induced pluripotent stem cells (iPSC) hold promise towards advancing the field of small fiber neuropathies.
    NEW METHOD: Here, we report a quick and efficient protocol to generate human sensory neurons from iPSC within ten days.
    RESULTS: The generated neurons expressed generic sensory markers (Brn3A, Islet 1, and neurofilament M) as well as the sensory neuron-associated sodium channel subtypes NaV1.7 and NaV1.8. Additionally, ∼80% of generated sensory neurons were positive for transient receptor potential vanilloid 1 (TRPV-1), a marker for unmyelinated sensory axons.
    COMPARISON WITH OTHER METHODS: Previous investigators have generated sensory neurons from iPSCs, with a protocol length range of up to 42 days. Most methodologies either employ a small molecule differentiation or an "accelerated" method, whereas our new model is generated by utilizing mRNA.
    CONCLUSION: This novel protocol enables rapid generation of human sensory neurons from human iPSCs, achieving 60-70% efficiency. A shorter protocol can improve modeling of small-fiber neuropathies - for example, diabetic peripheral neuropathy and toxic conditions like chemotherapy-induced peripheral neuropathy.
    Keywords:  Human sensory neurons; IPSC differentiation; Neuropathy modeling; Peripheral axons
    DOI:  https://doi.org/10.1016/j.jneumeth.2026.110837
  12. Mol Biol Rep. 2026 Jun 23. pii: 975. [Epub ahead of print]53(1):
      Ischemic stroke, a serious disease that threatens to human health, is caused by insufficient blood supply due to cerebrovascular occlusion, leading to severe brain damage and neurological deficits. Numerous investigations have revealed that autophagy is extensively involved in the pathophysiological processes of ischemic stroke. Autophagy is a vital mechanism to maintain neuronal homeostasis by degradation and recycling of cytoplasmic components. It comprises a series of consecutive processes, including autophagy initiation, autophagosome formation, fusion of autophagosomes with lysosomes, and degradation of autophagic substrates within autolysosomes. Thus, autophagy is termed as autophagic flux, as well as autophagic/lysosomal signaling pathway. Several key steps in autophagic signaling pathway are prominently regulated by post-translational modifications, thereby significantly affecting neurological outcomes after ischemic stroke. However, how the post-translational modifications regulate autophagic flux to mitigate ischemic neuronal injury remains to be systematically expounded. To provide insights into the researches on the pathogenesis and neuroprotection of ischemic stroke, this article is to summarize the post-translational modifications involved in autophagic/lysosomal signaling pathway in neurons after ischemic stroke, especially highlighting the effects of acetylation and phosphorylation on post-stroke pathophysiological processes.
    Keywords:  Autophagy; Ischemic stroke; Neuron; Post-translational modification
    DOI:  https://doi.org/10.1007/s11033-026-12177-z
  13. Science. 2026 Jun 25. 392(6805): 1363-1368
      Impairments in intracellular quality-control mechanisms, including autophagy, affect neuronal integrity and function. Despite numerous studies aimed at slowing neuronal deterioration, it remains unclear whether neuronal function and intracellular quality can be restored once impaired. We developed a mouse model in which autophagy could be rapidly and reversibly regulated to investigate the reversibility of such defects. Suppressing autophagy led to proteome and transcriptome changes, inclusion body accumulation, and axonal swelling, all of which were largely ameliorated after autophagy restoration. Consistent with these cellular abnormalities, autophagy suppression induced motor and cognitive dysfunction, which was also reversed on autophagy restoration. Our findings elucidate the potential resilience of neuronal function and quality enabled by intracellular clearance.
    DOI:  https://doi.org/10.1126/science.ady3911
  14. iScience. 2026 Jul 17. 29(7): 116362
      Synaptic proteins are critical for maintaining healthy neuronal transmission but can also drive prion-like trans-synaptic spreading of pathological aggregated proteins found in many neurodegenerative diseases, including Alzheimer's disease. Recognizing technological limitations for in situ identification of synaptic proteins, we built a modular synaptic chimeric antigen receptor (synCAR) for capture of synaptic proteins by fusing a single-chain antibody fragment with the post-synaptic protein neurolignin-1 (NLGN1). Using our synCAR platform, we show that anchoring the tau antibody PHF1 to the synapse effectively captures pathogenic synaptic tau species. Expressing PHF1 synCAR at synapses in mouse primary and human neuronal tau seeding models results in increased tau aggregation, likely due to concentrating pathological tau seeds at the synapse. These findings provide the first published method for the isolation and modulation of synaptic protein function within relevant biological contexts, highlighting synCAR as a relevant instrumental platform for synaptic protein research and neurodegenerative disease drug development.
    Keywords:  Cell biology; Molecular biology; Neuroscience
    DOI:  https://doi.org/10.1016/j.isci.2026.116362
  15. Nat Neurosci. 2026 Jun 26.
      Mitochondria have evolved a specialized mitochondrial unfolded protein response (UPRmt) to maintain proteostasis and promote recovery under stress. Studies in simple organisms have shown that UPRmt activation in glial cells supports proteostasis through beneficial non-cell-autonomous communication with neurons. However, the role of mitochondrial stress responses in the human brain remains unclear. To address this gap, we investigated the cell-type-specific effects of mitochondrial proteotoxic stress using human induced pluripotent stem cell-derived neuronal and glial cultures, as well as brain organoids. Here we show that mitochondrial proteotoxic stress induces metabolic rewiring in human microglia, marked by depletion of S-adenosylmethionine and lipid remodeling, ultimately leading to a senescent phenotype. Using human neuronal-glial tricultures and microglia-containing brain organoids, we identified the specific contributions of microglia to brain senescence and mitochondrial stress-driven neurodegenerative processes. UPRmt activation disrupts microglial communication with neighboring cells, triggering inflammatory signaling and impairing proteostasis. Together, these findings reveal how impaired mitochondrial proteostasis alters intercellular networks and identify a critical role for the UPRmt in neurodegenerative disease pathogenesis.
    DOI:  https://doi.org/10.1038/s41593-026-02320-1
  16. EMBO Mol Med. 2026 Jun 26.
      Huntington's disease (HD) is a hereditary movement disorder caused by a CAG repeat expansion in the huntingtin gene. HD is characterized by deposition of mutant huntingtin (mHTT) aggregates, and by severe neurodegeneration of the basal ganglia and neocortex. No cure is currently available, and new treatment options are urgently needed. Here, we show that the oligomer modifying molecule anle138b (INN: emrusolmin) improves multiple disease phenotypes in cell culture and in two mouse models of HD. Application of anle138b reduced mHTT aggregate formation and ameliorated neurotoxicity in primary neurons. Oral administration of anle138b delayed deposition of mHTT inclusions, reduced brain atrophy, mitigated neuroinflammation and transcriptional alterations, improved motor function and extended life span in HD mice. Downregulation of striatal markers and synapse loss in striatal spiny projection neurons were also partially rescued. No adverse effects of anle138b were observed in wildtype animals. Moreover, anle138b markedly decreased mHTT aggregation in human neural precursor cells differentiated from HD patient-derived induced pluripotent stem cells (iPSCs). Altogether these results illustrate the potential of anle138b as a disease-modifying treatment for HD.
    DOI:  https://doi.org/10.1038/s44321-026-00459-9
  17. J Cell Biol. 2026 Sep 07. pii: e202507087. [Epub ahead of print]225(9):
      Lysosomes clear unwanted cellular material delivered by constant membrane fusion. Membrane fission is thus required to balance lysosome size, number, and composition. PIKfyve is a lipid kinase that converts phosphatidylinositol-3-phosphate [PtdIns(3)P] to phosphatidylinositol-3,5-bisphosphate [PtdIns(3,5)P2] and promotes lysosome fission since lysosomes coalesce into larger, but fewer, organelles in its absence. Here, we reveal a role for PIKfyve in regulating ER dynamics. We show the ER is less reticulated and motile in cells inhibited for PIKfyve. Partly, this arises because lysosomes cluster perinuclearly and are less motile, which appears to arrest ER hitchhiking, a process in which lysosomes pull and form ER tubules. Secondly, the ER morphology is distorted because of hyper-tethering of protrudin, an ER transmembrane protein, to lysosomes via excess PtdIns(3)P and protrudin's FYVE domain. Our findings reveal that PIKfyve balances phosphoinositides at ER-lysosome contact sites to govern ER properties and have significant implications for our understanding of PIKfyve function and of diseases linked to its dysfunction.
    DOI:  https://doi.org/10.1083/jcb.202507087
  18. Biochem Soc Trans. 2026 Jun 24. 54(6): 803-814
      Protein aggregates are a pathological hallmark of diverse disorders, including many neurodegenerative diseases, but also cardiometabolic disease and cancer. While the ubiquitin-proteasome system efficiently removes many soluble misfolded proteins, large or persistent assemblies often require the autophagy-lysosome pathway for their degradation. In the present mini-review, we summarize our knowledge of aggrephagy, the selective clearance of protein aggregates by autophagy, and discuss two recent manuscripts that argue that some aggregates must be primed for autophagosomal degradation, through chaperone-mediated remodeling. Aggrephagy substrates are defined by aggregate architecture, biophysical state, surface accessibility, and the physical constraints of membrane capture. These features help to explain why recruitment of selective autophagy receptors is necessary yet insufficient for clearance. Receptor clustering is required to concentrate early autophagy factors to establish initiation hubs, but successful degradation often requires upstream generation of smaller 'aggrephagy-competent' cargo units, which contain autophagy receptor clusters that successfully initiate autophagosome formation. Recent work supports a model in which larger aggregates are cleared through stepwise degradation enabled by prior remodeling steps that involve p97/VCP-driven disintegration or a chaperone module (DNAJB6-HSP70-HSP110) cooperating with the proteasomal 19S regulatory particle.
    Keywords:  autophagy; cellular protein quality control; molecular chaperones; piecemeal; selective autophagy receptors
    DOI:  https://doi.org/10.1042/BST20250460
  19. NPJ Parkinsons Dis. 2026 Jun 24.
      Mutations in PTEN-induced putative kinase 1 (PINK1) cause early-onset, autosomal-recessive Parkinson's disease (PD). While previous studies have shown age-related declines in dopamine release and ATP levels in Pink1-/- mice, the mechanisms remain unclear. Using a novel TH-Mito-Dendra2 transgenic mouse model to label dopaminergic neuron mitochondria, we show that PINK1 loss leads to age-dependent defects in axonal mitochondrial trafficking in acute brain slices. These deficits are characterized by reduced anterograde transport and increased mitochondrial stalling. Pharmacological induction of reactive oxygen species (ROS) and calcium release impaired mitochondrial mobility. Consistent with this, Pink1 knockout mice exhibited elevated mitochondrial calcium, oxidation levels, and p38 MAPK hyperactivation. Treatment with a calcium channel blocker and p38 inhibitor SB202190 restored mitochondrial motility and increased anterograde transport. Together, our findings suggest that PINK1 loss disrupts mitochondrial trafficking by disturbing calcium and redox homeostasis via the p38 pathway, contributing to PD pathogenesis.
    DOI:  https://doi.org/10.1038/s41531-026-01443-3
  20. bioRxiv. 2026 Jun 10. pii: 2026.06.08.731026. [Epub ahead of print]
      The prion-like spread of tau from cell to cell in the central nervous system involves escape from the endolysosomal network, which is counteracted by the lysosomal repair activity of the ESCRT system. Here, we investigate whether other components of the lysosomal damage sensing and repair system, namely the ESCRT-recruiting Ca 2+ sensor ALG-2, conjugation of ATG8s to single membranes (CASM), the phosphoinositide-initiated tethering and lipid transport (PITT) pathway, and the Parkinson's disease-related lipid transporter VPS13C are involved in tau spread. We found that the PITT pathway and VPS13C are strongly implicated in tau seeding by pre-formed fibrils (PFFs) in both neurons and astrocytes, CASM has a major role in astrocytes but not neurons, and ALG-2 has a lesser role in both. We then investigated the mechanism of damage and seeding by tau PFFs using cryo-electron tomography. Unlike the classical lysosome damage agent LLOMe, tau PFFs were not seen to directly interact with the lysosomal membrane, nor do they distort local membrane curvature. Lysosomes in PFF-treated cells were structurally intact. Extensive protein aggregates of similar character were seen in both the lysosomal lumen and in the cytosol proximal to lysosomes. The observations are consistent with the PFF-induced co-aggregation of tau with other cellular materials within lysosomes, with leakage to the cytosol attributed to reversible holes in the lysosome membrane.
    DOI:  https://doi.org/10.64898/2026.06.08.731026
  21. Front Pharmacol. 2026 ;17 1829420
       Introduction: Tau pathology is a major feature of Alzheimer's disease (AD) and multiple other adult-onset neurodegenerative diseases. Aberrant exposure of an N-terminal phosphatase-activating domain (PAD) is characteristic of pathological tau, representing a toxic gain of function. Exposure of the PAD in pathological tau leads to dysregulation of protein phosphatase 1/glycogen synthase kinase 3 (PP1/ GSK3β) signaling, inhibition of fast axonal transport, synaptic dysfunction, and altered transcription, along with other pathological consequences. Previous studies showed that TNT1, an antibody against the PAD, blocked toxicity of pathogenic forms of tau.
    Methods: In this article, we describe a high-throughput screen for small molecules that block TNT1 binding to the PAD in an AlphaLISA screen and bind specifically to the PAD in surface plasmon resonance assays. Candidate PAD ligands (PADis) were identified, and initial biochemical and biophysical optimization produced PADis with increased affinity and selectivity. Three candidate PADis were evaluated in neuronal (rat E18 embryonic cortical neurons) and non-neuronal cells (HEK293T human embryonic kidney cells) using a nano-bioluminescence resonance energy transfer (nanoBRET) assay to assess PP1 binding and cell toxicity.
    Results and Discussion: All three compounds prevented PP1 binding to PAD and neurite degeneration due to pathological tau in primary cultured cortical neurons. The final candidates had an IC50 value between 10 and 20 nM in neurons with low cytotoxicity, CC50 > 75 μM in primary cultured neurons, and 40-100 μM in non-neuronal cells. PADi treatment of primary cultured neurons transfected with pathogenic tau restored axonal growth and prevented neurodegeneration. These studies establish a novel approach to therapeutics for Alzheimer's disease and tauopathies.
    Keywords:  glycogen synthase kinase 3β; neuroprotection; phosphatase-activating domain; small-molecule inhibitor; tau; tauopathies
    DOI:  https://doi.org/10.3389/fphar.2026.1829420
  22. ACS Appl Bio Mater. 2026 Jun 26.
      The nervous system constitutes a highly ordered, integrated network of cells. Understanding this neuroanatomical architecture in vitro is fundamental to elucidating the cellular computations underlying functional network formation. Neuronal connectivity orchestrated through axonal pathfinding arises from an interplay of biochemical signals and electromechanical properties of the growth substrate. Our study focuses on how neurons' morphology and spatial organization are affected by the periodic, micrometer-scale patterned stripes of two electrically contrasting polymers-poly(vinylidenefluoride-trifluoroethylene) (PVDF-TrFE) and poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS). This periodic confinement provides a length-scale-driven cue, which unfolds as a self-organized, spatial guidance phenomenon. Primary cortical cultures on these patterned substrates reveal significant differences-with more elaborate neurite outgrowth and morphological complexity on the PVDF-TrFE stripe. The features observed at the stripe boundaries, along with the network dependence on stripe width, suggest that the neurons exhibit a preference to remain confined within the PVDF-TrFE region, with growth cones deflecting away from the PEDOT:PSS regions. These morphological observations demonstrate a proof-of-concept substrate design for future development of a functional bioinstructive template capable of directing axonal growth, with potential implications for early models of connectivity disorders in vivo.
    Keywords:  PEDOT:PSS; PVDF-TrFE; axon pathfinding; neural rewiring; neurite guidance; patterned biointerface
    DOI:  https://doi.org/10.1021/acsabm.6c00477