bims-nenemi Biomed News
on Neuroinflammation, neurodegeneration and mitochondria
Issue of 2024–03–31
twelve papers selected by
Marco Tigano, Thomas Jefferson University
  1. DELE1 promotes translation-associated homeostasis, growth, and survival in mitochondrial myopathy.
  2. Mapping Stress-Responsive Signaling Pathways Induced by Mitochondrial Proteostasis Perturbations.
  3. A stagewise response to mitochondrial dysfunction in mitochondrial DNA maintenance disorders.
  4. Distinct types of intramitochondrial protein aggregates protect mitochondria against proteotoxic stress.
  5. OMA1 protease eliminates arrested protein import intermediates upon mitochondrial depolarization.
  6. Quantitative imaging and semiotic phenotyping of mitochondrial network morphology in live human cells.
  7. Initiation of a ZAKα-dependent ribotoxic stress response by the innate immunity endoribonuclease RNase L.
  8. Defective mitochondria remodelling in B cells leads to an aged immune response.
  9. Mitochondrial H2O2 release does not directly cause damage to chromosomal DNA.
  10. Bioorthogonal photocatalytic proximity labeling in primary living samples.
  11. Generation of iPSCs from identical twin, one affected by LHON and one unaffected, both carrying a combination of two mitochondrial variants: m.14484 T>C and m.10680G>A.
  12. Disease phenotypic screening in neuron-glia cocultures identifies blockers of inflammatory neurodegeneration.
  1. bioRxiv. 2024 Feb 29. pii: 2024.02.29.582673. [Epub ahead of print]
    DELE1 promotes translation-associated homeostasis, growth, and survival in mitochondrial myopathy.
    Hsin-Pin Lin, Jennifer D Petersen, Alexandra J Gilsrud, Angelo Madruga, Theresa M D'Silva, Xiaoping Huang, Mario K Shammas, Nicholas P Randolph, Yan Li, Drew R Jones, Michael E Pacold, Derek P Narendra.
      Mitochondrial dysfunction causes devastating disorders, including mitochondrial myopathy. Here, we identified that diverse mitochondrial myopathy models elicit a protective mitochondrial integrated stress response (mt-ISR), mediated by OMA1-DELE1 signaling. The response was similar following disruptions in mtDNA maintenance, from knockout of Tfam , and mitochondrial protein unfolding, from disease-causing mutations in CHCHD10 (G58R and S59L). The preponderance of the response was directed at upregulating pathways for aminoacyl-tRNA biosynthesis, the intermediates for protein synthesis, and was similar in heart and skeletal muscle but more limited in brown adipose challenged with cold stress. Strikingly, models with early DELE1 mt-ISR activation failed to grow and survive to adulthood in the absence of Dele1 , accounting for some but not all of OMA1's protection. Notably, the DELE1 mt-ISR did not slow net protein synthesis in stressed striated muscle, but instead prevented loss of translation-associated proteostasis in muscle fibers. Together our findings identify that the DELE1 mt-ISR mediates a stereotyped response to diverse forms of mitochondrial stress and is particularly critical for maintaining growth and survival in early-onset mitochondrial myopathy.
    DOI:  https://doi.org/10.1101/2024.02.29.582673
  2. Mol Biol Cell. 2024 Mar 27. mbcE24010041
    Mapping Stress-Responsive Signaling Pathways Induced by Mitochondrial Proteostasis Perturbations.
    Nicole Madrazo, Zinia Khattar, Evan T Powers, Jessica D Rosarda, R Luke Wiseman.
      Imbalances in mitochondrial proteostasis are associated with pathologic mitochondrial dysfunction implicated in etiologically-diverse diseases. This has led to considerable interest in defining the mechanisms responsible for regulating mitochondria in response to mitochondrial stress. Numerous stress-responsive signaling pathways have been suggested to regulate mitochondria in response to proteotoxic stress. These include the integrated stress response (ISR), the heat shock response (HSR), and the oxidative stress response (OSR). Here, we define the stress signaling pathways activated in response to chronic mitochondrial proteostasis perturbations by monitoring the expression of sets of genes regulated downstream of each of these signaling pathways in published Perturb-seq datasets from K562 cells CRISPRi-depleted of mitochondrial proteostasis factors. Interestingly, we find that the ISR is preferentially activated in response to chronic, genetically-induced mitochondrial proteostasis stress, with no other pathway showing significant activation. Further, we demonstrate that CRISPRi depletion of other mitochondria-localized proteins similarly shows preferential activation of the ISR relative to other stress-responsive signaling pathways. These results both establish our gene set profiling approach as a viable strategy to probe stress responsive signaling pathways induced by perturbations to specific organelles and identify the ISR as the predominant stress-responsive signaling pathway activated in response to chronically disrupted of mitochondrial proteostasis.
    DOI:  https://doi.org/10.1091/mbc.E24-01-0041
  3. Biochim Biophys Acta Mol Basis Dis. 2024 Mar 21. pii: S0925-4439(24)00120-0. [Epub ahead of print] 167131
    A stagewise response to mitochondrial dysfunction in mitochondrial DNA maintenance disorders.
    Amy E Vincent, Chun Chen, Tiago Bernardino Gomes, Valeria Di Leo, Tuomas Laalo, Kamil Pabis, Rodrick Capaldi, Michael F Marusich, David McDonald, Andrew Filby, Andrew Fuller, Diana Lehmann Urban, Stephan Zierz, Marcus Deschauer, Doug Turnbull, Amy K Reeve, Conor Lawless.
      Mitochondrial DNA (mtDNA) deletions which clonally expand in skeletal muscle of patients with mtDNA maintenance disorders, impair mitochondrial oxidative phosphorylation dysfunction. Previously we have shown that these mtDNA deletions arise and accumulate in perinuclear mitochondria causing localised mitochondrial dysfunction before spreading through the muscle fibre. We believe that mito-nuclear signalling is a key contributor in the accumulation and spread of mtDNA deletions, and that knowledge of how muscle fibres respond to mitochondrial dysfunction is key to our understanding of disease mechanisms. To understand the contribution of mito-nuclear signalling to the spread of mitochondrial dysfunction, we use imaging mass cytometry. We characterise the levels of mitochondrial Oxidative Phosphorylation proteins alongside a mitochondrial mass marker, in a cohort of patients with mtDNA maintenance disorders. Our expanded panel included protein markers of key signalling pathways, allowing us to investigate cellular responses to different combinations of oxidative phosphorylation dysfunction and ragged red fibres. We find combined Complex I and IV deficiency to be most common. Interestingly, in fibres deficient for one or more complexes, the remaining complexes are often upregulated beyond the increase of mitochondrial mass typically observed in ragged red fibres. We further find that oxidative phosphorylation deficient fibres exhibit an increase in the abundance of proteins involved in proteostasis, e.g. HSP60 and LONP1, and regulation of mitochondrial metabolism (including oxidative phosphorylation and proteolysis, e.g. PHB1). Our analysis suggests that the cellular response to mitochondrial dysfunction changes depending on the combination of deficient oxidative phosphorylation complexes in each fibre.
    Keywords:  Cell signalling; Mitochondrial DNA deletion; Mitochondrial disease; Myopathy; OXPHOS
    DOI:  https://doi.org/10.1016/j.bbadis.2024.167131
  4. Cell Rep. 2024 Mar 28. pii: S2211-1247(24)00346-2. [Epub ahead of print]43(4): 114018
    Distinct types of intramitochondrial protein aggregates protect mitochondria against proteotoxic stress.
    Lea Bertgen, Jan-Eric Bökenkamp, Tim Schneckmann, Christian Koch, Markus Räschle, Zuzana Storchová, Johannes M Herrmann.
      Mitochondria consist of hundreds of proteins, most of which are inaccessible to the proteasomal quality control system of the cytosol. How cells stabilize the mitochondrial proteome during challenging conditions remains poorly understood. Here, we show that mitochondria form spatially defined protein aggregates as a stress-protecting mechanism. Two different types of intramitochondrial protein aggregates can be distinguished. The mitoribosomal protein Var1 (uS3m) undergoes a stress-induced transition from a soluble, chaperone-stabilized protein that is prevalent under benign conditions to an insoluble, aggregated form upon acute stress. The formation of Var1 bodies stabilizes mitochondrial proteostasis, presumably by sequestration of aggregation-prone proteins. The AAA chaperone Hsp78 is part of a second type of intramitochondrial aggregate that transiently sequesters proteins and promotes their folding or Pim1-mediated degradation. Thus, mitochondrial proteins actively control the formation of distinct types of intramitochondrial protein aggregates, which cooperate to stabilize the mitochondrial proteome during proteotoxic stress conditions.
    Keywords:  CP: Cell biology; CP: Molecular biology; Hsp78; MitoStores; Pim1 protease; Var1 bodies; aggregates; chaperones; mitochondria; mitoribosome; protein folding; protein import
    DOI:  https://doi.org/10.1016/j.celrep.2024.114018
  5. J Cell Biol. 2024 May 06. pii: e202306051. [Epub ahead of print]223(5):
    OMA1 protease eliminates arrested protein import intermediates upon mitochondrial depolarization.
    Magda Krakowczyk, Anna M Lenkiewicz, Tomasz Sitarz, Dominika Malinska, Mayra Borrero, Ben Hur Marins Mussulini, Vanessa Linke, Andrzej A Szczepankiewicz, Joanna M Biazik, Agata Wydrych, Hanna Nieznanska, Remigiusz A Serwa, Agnieszka Chacinska, Piotr Bragoszewski.
      Most mitochondrial proteins originate from the cytosol and require transport into the organelle. Such precursor proteins must be unfolded to pass through translocation channels in mitochondrial membranes. Misfolding of transported proteins can result in their arrest and translocation failure. Arrested proteins block further import, disturbing mitochondrial functions and cellular proteostasis. Cellular responses to translocation failure have been defined in yeast. We developed the cell line-based translocase clogging model to discover molecular mechanisms that resolve failed import events in humans. The mechanism we uncover differs significantly from these described in fungi, where ATPase-driven extraction of blocked protein is directly coupled with proteasomal processing. We found human cells to rely primarily on mitochondrial factors to clear translocation channel blockage. The mitochondrial membrane depolarization triggered proteolytic cleavage of the stalled protein, which involved mitochondrial protease OMA1. The cleavage allowed releasing the protein fragment that blocked the translocase. The released fragment was further cleared in the cytosol by VCP/p97 and the proteasome.
    DOI:  https://doi.org/10.1083/jcb.202306051
  6. PLoS One. 2024 ;19(3): e0301372
    Quantitative imaging and semiotic phenotyping of mitochondrial network morphology in live human cells.
    Sophie Charrasse, Victor Racine, Charlotte Saint-Omer, Titouan Poquillon, Loïc Lionnard, Marine Ledru, Christophe Gonindard, Sandrine Delaunois, Karima Kissa, Richard E Frye, Manuela Pastore, Christelle Reynes, Mathilde Frechet, Hanane Chajra, Abdel Aouacheria.
      The importance of mitochondria in tissue homeostasis, stress responses and human diseases, combined to their ability to transition between various structural and functional states, makes them excellent organelles for monitoring cell health. There is therefore a need for technologies to accurately analyze and quantify changes in mitochondrial organization in a variety of cells and cellular contexts. Here we present an innovative computerized method that enables accurate, multiscale, fast and cost-effective analysis of mitochondrial shape and network architecture from confocal fluorescence images by providing more than thirty features. In order to facilitate interpretation of the quantitative results, we introduced two innovations: the use of Kiviat-graphs (herein named MitoSpider plots) to present highly multidimensional data and visualization of the various mito-cellular configurations in the form of morphospace diagrams (called MitoSigils). We tested our fully automated image analysis tool on rich datasets gathered from live normal human skin cells cultured under basal conditions or exposed to specific stress including UVB irradiation and pesticide exposure. We demonstrated the ability of our proprietary software (named MitoTouch) to sensitively discriminate between control and stressed dermal fibroblasts, and between normal fibroblasts and other cell types (including cancer tissue-derived fibroblasts and primary keratinocytes), showing that our automated analysis captures subtle differences in morphology. Based on this novel algorithm, we report the identification of a protective natural ingredient that mitigates the deleterious impact of hydrogen peroxide (H2O2) on mitochondrial organization. Hence we conceived a novel wet-plus-dry pipeline combining cell cultures, quantitative imaging and semiotic analysis for exhaustive analysis of mitochondrial morphology in living adherent cells. Our tool has potential for broader applications in other research areas such as cell biology and medicine, high-throughput drug screening as well as predictive and environmental toxicology.
    DOI:  https://doi.org/10.1371/journal.pone.0301372
  7. Cell Rep. 2024 Mar 28. pii: S2211-1247(24)00326-7. [Epub ahead of print]43(4): 113998
    Initiation of a ZAKα-dependent ribotoxic stress response by the innate immunity endoribonuclease RNase L.
    Jiajia Xi, Goda Snieckute, José Francisco Martínez, Frederic Schrøder Wenzel Arendrup, Abhishek Asthana, Christina Gaughan, Anders H Lund, Simon Bekker-Jensen, Robert H Silverman.
      RNase L is an endoribonuclease of higher vertebrates that functions in antiviral innate immunity. Interferons induce oligoadenylate synthetase enzymes that sense double-stranded RNA of viral origin leading to the synthesis of 2',5'-oligoadenylate (2-5A) activators of RNase L. However, it is unknown precisely how RNase L remodels the host cell transcriptome. To isolate effects of RNase L from other effects of double-stranded RNA or virus, 2-5A is directly introduced into cells. Here, we report that RNase L activation by 2-5A causes a ribotoxic stress response involving the MAP kinase kinase kinase (MAP3K) ZAKα, MAP2Ks, and the stress-activated protein kinases JNK and p38α. RNase L activation profoundly alters the transcriptome by widespread depletion of mRNAs associated with different cellular functions but also by JNK/p38α-stimulated induction of inflammatory genes. These results show that the 2-5A/RNase L system triggers a protein kinase cascade leading to proinflammatory signaling and apoptosis.
    Keywords:  2-5A; CP: Immunology; OAS; RNase L; ZAKalpha; innate immunity; ribotoxic stress response
    DOI:  https://doi.org/10.1016/j.celrep.2024.113998
  8. Nat Commun. 2024 Mar 22. 15(1): 2569
    Defective mitochondria remodelling in B cells leads to an aged immune response.
    Marta Iborra-Pernichi, Jonathan Ruiz García, María Velasco de la Esperanza, Belén S Estrada, Elena R Bovolenta, Claudia Cifuentes, Cristina Prieto Carro, Tamara González Martínez, José García-Consuegra, María Fernanda Rey-Stolle, Francisco Javier Rupérez, Milagros Guerra Rodriguez, Rafael J Argüello, Sara Cogliati, Fernando Martín-Belmonte, Nuria Martínez-Martín.
      The B cell response in the germinal centre (GC) reaction requires a unique bioenergetic supply. Although mitochondria are remodelled upon antigen-mediated B cell receptor stimulation, mitochondrial function in B cells is still poorly understood. To gain a better understanding of the role of mitochondria in B cell function, here we generate mice with B cell-specific deficiency in Tfam, a transcription factor necessary for mitochondrial biogenesis. Tfam conditional knock-out (KO) mice display a blockage of the GC reaction and a bias of B cell differentiation towards memory B cells and aged-related B cells, hallmarks of an aged immune response. Unexpectedly, blocked GC reaction in Tfam KO mice is not caused by defects in the bioenergetic supply but is associated with a defect in the remodelling of the lysosomal compartment in B cells. Our results may thus describe a mitochondrial function for lysosome regulation and the downstream antigen presentation in B cells during the GC reaction, the dysruption of which is manifested as an aged immune response.
    DOI:  https://doi.org/10.1038/s41467-024-46763-1
  9. Nat Commun. 2024 Mar 28. 15(1): 2725
    Mitochondrial H2O2 release does not directly cause damage to chromosomal DNA.
    Daan M K van Soest, Paulien E Polderman, Wytze T F den Toom, Janneke P Keijer, Markus J van Roosmalen, Tim M F Leyten, Johannes Lehmann, Susan Zwakenberg, Sasha De Henau, Ruben van Boxtel, Boudewijn M T Burgering, Tobias B Dansen.
      Reactive Oxygen Species (ROS) derived from mitochondrial respiration are frequently cited as a major source of chromosomal DNA mutations that contribute to cancer development and aging. However, experimental evidence showing that ROS released by mitochondria can directly damage nuclear DNA is largely lacking. In this study, we investigated the effects of H2O2 released by mitochondria or produced at the nucleosomes using a titratable chemogenetic approach. This enabled us to precisely investigate to what extent DNA damage occurs downstream of near- and supraphysiological amounts of localized H2O2. Nuclear H2O2 gives rise to DNA damage and mutations and a subsequent p53 dependent cell cycle arrest. Mitochondrial H2O2 release shows none of these effects, even at levels that are orders of magnitude higher than what mitochondria normally produce. We conclude that H2O2 released from mitochondria is unlikely to directly damage nuclear genomic DNA, limiting its contribution to oncogenic transformation and aging.
    DOI:  https://doi.org/10.1038/s41467-024-47008-x
  10. Nat Commun. 2024 Mar 28. 15(1): 2712
    Bioorthogonal photocatalytic proximity labeling in primary living samples.
    Ziqi Liu, Fuhu Guo, Yufan Zhu, Shengnan Qin, Yuchen Hou, Haotian Guo, Feng Lin, Peng R Chen, Xinyuan Fan.
      In situ profiling of subcellular proteomics in primary living systems, such as native tissues or clinic samples, is crucial for understanding life processes and diseases, yet challenging due to methodological obstacles. Here we report CAT-S, a bioorthogonal photocatalytic chemistry-enabled proximity labeling method, that expands proximity labeling to a wide range of primary living samples for in situ profiling of mitochondrial proteomes. Powered by our thioQM labeling warhead development and targeted bioorthogonal photocatalytic chemistry, CAT-S enables the labeling of mitochondrial proteins in living cells with high efficiency and specificity. We apply CAT-S to diverse cell cultures, dissociated mouse tissues as well as primary T cells from human blood, portraying the native-state mitochondrial proteomic characteristics, and unveiled hidden mitochondrial proteins (PTPN1, SLC35A4 uORF, and TRABD). Furthermore, CAT-S allows quantification of proteomic perturbations on dysfunctional tissues, exampled by diabetic mouse kidneys, revealing the alterations of lipid metabolism that may drive disease progression. Given the advantages of non-genetic operation, generality, and spatiotemporal resolution, CAT-S may open exciting avenues for subcellular proteomic investigations of primary samples that are otherwise inaccessible.
    DOI:  https://doi.org/10.1038/s41467-024-46985-3
  11. Stem Cell Res. 2024 Mar 24. pii: S1873-5061(24)00104-1. [Epub ahead of print]77 103406
    Generation of iPSCs from identical twin, one affected by LHON and one unaffected, both carrying a combination of two mitochondrial variants: m.14484 T>C and m.10680G>A.
    Camille Peron, Andrea Cavaliere, Chiara Fasano, Angelo Iannielli, Manuela Spagnolo, Andrea Legati, Maria Nicol Colombo, Ambra Rizzo, Francesca L Sciacca, Valerio Carelli, Vania Broccoli, Costanza Lamperti, Valeria Tiranti.
      Leber hereditary optic neuropathy (LHON) is one of the most common mitochondrial illness, causing retinal ganglion cell degeneration and central vision loss. It stems from point mutations in mitochondrial DNA (mtDNA), with key mutations being m.3460G > A, m.11778G > A, and m.14484 T > C. Fibroblasts from identical twins, sharing m.14484 T > C and m.10680G > A variants each with 70 % heteroplasmy, were used to generate iPSC lines. Remarkably, one twin, a LHON patient, displayed symptoms, while the other, a carrier, remained asymptomatic. These iPSCs offer a valuable tool for studying factors influencing disease penetrance and unravelling the role of m.10680G > A, which is still debated.
    DOI:  https://doi.org/10.1016/j.scr.2024.103406
  12. iScience. 2024 Apr 19. 27(4): 109454
    Disease phenotypic screening in neuron-glia cocultures identifies blockers of inflammatory neurodegeneration.
    Timothy J Y Birkle, Henriette M G Willems, John Skidmore, Guy C Brown.
      Neuropathology is often mediated by interactions between neurons and glia that cannot be modeled by monocultures. However, cocultures are difficult to use and analyze for high-content screening. Here, we perform compound screening using primary neuron-glia cultures to model inflammatory neurodegeneration, live-cell stains, and automated classification of neurons, astrocytes or microglia using open-source software. Out of 227 compounds with known bioactivities, 29 protected against lipopolysaccharide-induced neuronal loss, including drugs affecting adrenergic, steroid, inflammatory and MAP kinase signaling. The screen also identified physiological compounds, such as noradrenaline and progesterone, that protected and identified neurotoxic compounds, such as a TLR7 agonist, that induced microglial proliferation. Most compounds used here have not been tested in a neuron-glia coculture neurodegeneration assay previously. Thus, combining a complex cellular disease model with high-content screening of known compounds and automated image analysis allows identification of important biology, as well as potential targets and drugs for treatment.
    Keywords:  Bioinformatics; Neuroscience
    DOI:  https://doi.org/10.1016/j.isci.2024.109454
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