Pub Date : 2024-09-12DOI: 10.1101/2024.09.11.612392
Guinevere L Grice, Eleanor Minogue, Hudson W Coates, Mekdes Debela, Nicole Kaneider-Kaser, P Robin Antrobus, Randall S Johnson, James A Nathan
Glutarate is an intermediate of amino acid catabolism and an important metabolite for reprogramming T cell immunity, exerting its effects by inhibition of histone demethylase enzymes or through glutarylation. However, how distinct glutarate modifications are regulated is unclear. Here, we uncover a deglutarylation pathway that couples amino acid catabolism to tricarboxylic acid (TCA) cycle function. By examining how glutarate can form conjugates with lipoate, an essential mitochondrial modification for the TCA cycle, we find that Alpha Beta Hydrolase Domain 11 (ABHD11) protects against the formation of glutaryl-lipoyl adducts. Mechanistically, ABHD11 acts as a thioesterase to selectively remove glutaryl adducts from lipoate, maintaining integrity of the TCA cycle. Functionally, ABHD11 influences the metabolic reprogramming of human T cells, increasing central memory T cell formation and attenuating oxidative phosphorylation. These results uncover ABHD11 as a selective deglutarylating enzyme and highlight that targeting ABHD11 offers a potential approach to metabolically reprogramme cytotoxic T cells.
戊二酸是氨基酸分解代谢的中间产物，也是重编程 T 细胞免疫的重要代谢产物，它通过抑制组蛋白去甲基化酶或通过戊二酸化作用来发挥其效果。然而，谷氨酸的不同修饰是如何调控的还不清楚。在这里，我们发现了一条将氨基酸分解代谢与三羧酸（TCA）循环功能联系起来的脱谷氨酸途径。通过研究戊二酸如何与脂酸（一种线粒体对 TCA 循环的重要修饰）形成共轭物，我们发现α-β水解酶域 11（ABHD11）能防止戊二酸-脂酰加合物的形成。从机理上讲，ABHD11 可作为硫酯酶选择性地从脂酸中去除戊二酰加合物，从而保持 TCA 循环的完整性。在功能上，ABHD11 可影响人类 T 细胞的新陈代谢重编程，增加中枢记忆 T 细胞的形成，减弱氧化磷酸化。这些结果揭示了 ABHD11 作为一种选择性脱戊二酰化酶的作用，并强调以 ABHD11 为靶点可为细胞毒性 T 细胞的代谢重编程提供一种潜在的方法。
{"title":"ABHD11 mediated deglutarylation regulates the TCA cycle and T cell metabolism","authors":"Guinevere L Grice, Eleanor Minogue, Hudson W Coates, Mekdes Debela, Nicole Kaneider-Kaser, P Robin Antrobus, Randall S Johnson, James A Nathan","doi":"10.1101/2024.09.11.612392","DOIUrl":"https://doi.org/10.1101/2024.09.11.612392","url":null,"abstract":"Glutarate is an intermediate of amino acid catabolism and an important metabolite for reprogramming T cell immunity, exerting its effects by inhibition of histone demethylase enzymes or through glutarylation. However, how distinct glutarate modifications are regulated is unclear. Here, we uncover a deglutarylation pathway that couples amino acid catabolism to tricarboxylic acid (TCA) cycle function. By examining how glutarate can form conjugates with lipoate, an essential mitochondrial modification for the TCA cycle, we find that Alpha Beta Hydrolase Domain 11 (ABHD11) protects against the formation of glutaryl-lipoyl adducts. Mechanistically, ABHD11 acts as a thioesterase to selectively remove glutaryl adducts from lipoate, maintaining integrity of the TCA cycle. Functionally, ABHD11 influences the metabolic reprogramming of human T cells, increasing central memory T cell formation and attenuating oxidative phosphorylation. These results uncover ABHD11 as a selective deglutarylating enzyme and highlight that targeting ABHD11 offers a potential approach to metabolically reprogramme cytotoxic T cells.","PeriodicalId":501590,"journal":{"name":"bioRxiv - Cell Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142189953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Influenza A virus encodes its genome in eight segments of viral ribonucleoproteins (vRNPs) replicated in the host cell nucleus. Our understanding of host factors involved in driving vRNP selective packaging remains incomplete. To address this, we used advanced immuno-freeze-etch electron microscopy to visualise the vRNP packaging process and atomic force live-cell imaging (AFM) to examine the motility of membrane cytoskeletal actin filaments. In the cytoplasm, vRNPs were mainly localised on mottled membrane-like structures, suggesting intracellular trafficking through such structures. After reaching the cytoplasmic side surface of the plasma membrane, vRNPs formed many aggregates while associating with actin filaments. Antibody labelling also detected myosin along actin filaments entangled in vRNPs. Blocking myosin activity with blebbistatin prevented the active movement of membrane cytoskeletal actin filaments just below the plasma membrane visualised by AFM and abrogated proper aggregation of vRNPs. Thus, actomyosin motility appears to be crucial for the selective packaging of vRNPs.
{"title":"Influenza A virus exploits the motility of membrane cytoskeletal actomyosin filaments for its genome packaging in the host cell","authors":"I-Hsuan Wang, Jiro Usukura, Yasuyuki Miyake, Eiji Usukura, Akihiro Narita, Yohei Yamauchi, Yoshihiro Kawaoka","doi":"10.1101/2024.09.11.612468","DOIUrl":"https://doi.org/10.1101/2024.09.11.612468","url":null,"abstract":"Influenza A virus encodes its genome in eight segments of viral ribonucleoproteins (vRNPs) replicated in the host cell nucleus. Our understanding of host factors involved in driving vRNP selective packaging remains incomplete. To address this, we used advanced immuno-freeze-etch electron microscopy to visualise the vRNP packaging process and atomic force live-cell imaging (AFM) to examine the motility of membrane cytoskeletal actin filaments. In the cytoplasm, vRNPs were mainly localised on mottled membrane-like structures, suggesting intracellular trafficking through such structures. After reaching the cytoplasmic side surface of the plasma membrane, vRNPs formed many aggregates while associating with actin filaments. Antibody labelling also detected myosin along actin filaments entangled in vRNPs. Blocking myosin activity with blebbistatin prevented the active movement of membrane cytoskeletal actin filaments just below the plasma membrane visualised by AFM and abrogated proper aggregation of vRNPs. Thus, actomyosin motility appears to be crucial for the selective packaging of vRNPs.","PeriodicalId":501590,"journal":{"name":"bioRxiv - Cell Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142189951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-12DOI: 10.1101/2024.09.12.612759
Purnima Devaki Bhat, Aswan Nalli, Luke Shoemaker, Jennifer Q. Kwong, Prasanna Krishnamurthy, Guy M. Benian
The exquisitely organized sarcomere, the unit of contraction of striated muscle, is a very stable structure with a slow turnover rate of its components. The myosin chaperone UNC-45 and its co-chaperones, Hsp90 and Hsp70, are required for the initial folding of the myosin head domain and the assembly of myosin into thick filaments. There is increasing evidence that the UNC-45 chaperone system has an important role during aging to preserve sarcomere organization and myosin levels, and its decline may be a key factor in sarcopenia, the reduced skeletal muscle mass and function found in the elderly without an underlying condition. Cardiac muscle is another type of striated muscle but the role of the UNC-45 system has not yet been examined in the aging heart. Here we show that in the mouse heart, during aging, there is a decline in the levels of myosin, Unc-45b and Hsp70, but not Hsp90, and no obvious changes in sarcomere organization. In contrast, it is known that in skeletal muscle, there is a decline in both Unc-45b and Hsp90, and we show here that there is no decline in Hsp70. The decreased level of Hsp70 specifically in the heart could have broader implications than seem apparent as it could affect the folding and assembly of many other proteins in the aging heart and contribute to cardiomyopathies. Since Hsp70 mediates protein stabilization and prevents protein aggregation, its age-dependent reduction could potentially affect diseases such as amyloidosis.
{"title":"Age-dependent Changes in a Chaperone Complex in the Mouse Heart","authors":"Purnima Devaki Bhat, Aswan Nalli, Luke Shoemaker, Jennifer Q. Kwong, Prasanna Krishnamurthy, Guy M. Benian","doi":"10.1101/2024.09.12.612759","DOIUrl":"https://doi.org/10.1101/2024.09.12.612759","url":null,"abstract":"The exquisitely organized sarcomere, the unit of contraction of striated muscle, is a very stable structure with a slow turnover rate of its components. The myosin chaperone UNC-45 and its co-chaperones, Hsp90 and Hsp70, are required for the initial folding of the myosin head domain and the assembly of myosin into thick filaments. There is increasing evidence that the UNC-45 chaperone system has an important role during aging to preserve sarcomere organization and myosin levels, and its decline may be a key factor in sarcopenia, the reduced skeletal muscle mass and function found in the elderly without an underlying condition. Cardiac muscle is another type of striated muscle but the role of the UNC-45 system has not yet been examined in the aging heart. Here we show that in the mouse heart, during aging, there is a decline in the levels of myosin, Unc-45b and Hsp70, but not Hsp90, and no obvious changes in sarcomere organization. In contrast, it is known that in skeletal muscle, there is a decline in both Unc-45b and Hsp90, and we show here that there is no decline in Hsp70. The decreased level of Hsp70 specifically in the heart could have broader implications than seem apparent as it could affect the folding and assembly of many other proteins in the aging heart and contribute to cardiomyopathies. Since Hsp70 mediates protein stabilization and prevents protein aggregation, its age-dependent reduction could potentially affect diseases such as amyloidosis.","PeriodicalId":501590,"journal":{"name":"bioRxiv - Cell Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142189930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-12DOI: 10.1101/2024.09.11.612494
Won Jin Cho, Ha Vo, Yongxin Zhao, Douglas J Taatjes, Bhanu P Jena
Cystic fibrosis (CF) is a genetic disorder resulting from mutations in the CF Transmembrane Conductance Regulator (CFTR) gene that codes for a chloride transporting channel at the cell plasma membrane. In CF, highly viscous mucus is secreted in the airways preventing its clearance, leading to lung infections and respiratory failure. A major challenge in treating CF patients has been the presence of more than 2,000 different CFTR mutations or due to the absence of CFTR expression. CFTR is among the 34 major proteins composing the 100 nm porosome secretory machinery in the human airway epithelia, involved in mucin secretion. The airways is coated with a thin film of mucus, composed primarily of mucin MUC5AC and MUC5B. Sputum from patients with CF show a >70% decrease in MUC5B and MUC5AC secretion. Our studies using differentiated 3D cultures of human airway epithelial cell line, also demonstrate loss of both chloride and mucus secretion following exposure to CFTR inhibitors thiazolidinone 172 or the hydrazide GlyH101. Our studies show that human bronchial epithelial (HBE) cells with ΔF508 CFTR mutation, affects nearly a dozen porosome proteins including CFTR. Therefore, we hypothesized that the introduction of normal functional porosomes carrying wild type CFTR into the cell plasma membrane of CF cells would rescue from all forms of CF. Air liquid interface (ALI) 3D differentiated HBE WT-CFTR cells and ΔF508-CFTR CF HBE cell cultures mimicking normal lung physiology, responding to CFTR inhibitors and CF corrector and modulator drugs Tezacaftor, Ivacaftor and TRIKAFTA, was used in the study. Introduction of functional porosome complexes obtained from WT-CFTR HBE cells into the plasma membrane (PM) of ΔF508-CFTR CF cells, was demonstrated by an increase in PM-associated CFTR using Magnify expansion microscopy. Mucin secretion assays demonstrate porosome reconstitution to restore mucin secretion more than twice as effectively as TRIKAFTA. These results are further supported by preliminary nasal potential different studies in ΔF508 mice, where treatment of the nasal passage with porosome isolates from WT-CFTR HBE cells, restore chloride secretion in the nasal passage of mice, a further validation of the highly effective porosome reconstitution therapy for CF.
{"title":"Porosome reconstitution therapy: A biologic rescue from cystic fibrosis","authors":"Won Jin Cho, Ha Vo, Yongxin Zhao, Douglas J Taatjes, Bhanu P Jena","doi":"10.1101/2024.09.11.612494","DOIUrl":"https://doi.org/10.1101/2024.09.11.612494","url":null,"abstract":"Cystic fibrosis (CF) is a genetic disorder resulting from mutations in the CF Transmembrane Conductance Regulator (CFTR) gene that codes for a chloride transporting channel at the cell plasma membrane. In CF, highly viscous mucus is secreted in the airways preventing its clearance, leading to lung infections and respiratory failure. A major challenge in treating CF patients has been the presence of more than 2,000 different CFTR mutations or due to the absence of CFTR expression. CFTR is among the 34 major proteins composing the 100 nm porosome secretory machinery in the human airway epithelia, involved in mucin secretion. The airways is coated with a thin film of mucus, composed primarily of mucin MUC5AC and MUC5B. Sputum from patients with CF show a >70% decrease in MUC5B and MUC5AC secretion. Our studies using differentiated 3D cultures of human airway epithelial cell line, also demonstrate loss of both chloride and mucus secretion following exposure to CFTR inhibitors thiazolidinone 172 or the hydrazide GlyH101. Our studies show that human bronchial epithelial (HBE) cells with ΔF508 CFTR mutation, affects nearly a dozen porosome proteins including CFTR. Therefore, we hypothesized that the introduction of normal functional porosomes carrying wild type CFTR into the cell plasma membrane of CF cells would rescue from all forms of CF. Air liquid interface (ALI) 3D differentiated HBE WT-CFTR cells and ΔF508-CFTR CF HBE cell cultures mimicking normal lung physiology, responding to CFTR inhibitors and CF corrector and modulator drugs Tezacaftor, Ivacaftor and TRIKAFTA, was used in the study. Introduction of functional porosome complexes obtained from WT-CFTR HBE cells into the plasma membrane (PM) of ΔF508-CFTR CF cells, was demonstrated by an increase in PM-associated CFTR using Magnify expansion microscopy. Mucin secretion assays demonstrate porosome reconstitution to restore mucin secretion more than twice as effectively as TRIKAFTA. These results are further supported by preliminary nasal potential different studies in ΔF508 mice, where treatment of the nasal passage with porosome isolates from WT-CFTR HBE cells, restore chloride secretion in the nasal passage of mice, a further validation of the highly effective porosome reconstitution therapy for CF.","PeriodicalId":501590,"journal":{"name":"bioRxiv - Cell Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-12DOI: 10.1101/2024.09.12.612637
Mary Fesenko, Daniel Moore, Peyton Ewbank, Stephen J Royle
Cells are filled with thousands of vesicles, which mediate protein transport and ensure homeostasis of the endomembrane system. Distinguishing these vesicles functionally and molecularly represents a major challenge. Intracellular nanovesicles (INVs) are a large class of transport vesicles that likely comprises of multiple subtypes. Here, we define the INV proteome and find that it is molecularly heterogeneous, and enriched for transmembrane cargo molecules including integrins, transporters, and ATG9A, a lipid scramblase associated with autophagy. ATG9A is known to reside in 'ATG9 vesicles': small vesicles that contribute to autophagosome formation. Using in-cell vesicle capture assays we found that ATG9A, as well as other ATG9 vesicle cargos, were in INVs. Quantitative analysis showed that virtually all ATG9 vesicles are INVs, but that only ~20% of INVs are ATG9 vesicles, suggesting that ATG9 vesicles are in fact a subtype of INV, which we term ATG9A-flavor INVs. Finally, we show that perturbing ATG9A-flavor INVs impaired the autophagy response induced by starvation.
{"title":"ATG9 vesicles are a subtype of intracellular nanovesicle","authors":"Mary Fesenko, Daniel Moore, Peyton Ewbank, Stephen J Royle","doi":"10.1101/2024.09.12.612637","DOIUrl":"https://doi.org/10.1101/2024.09.12.612637","url":null,"abstract":"Cells are filled with thousands of vesicles, which mediate protein transport and ensure homeostasis of the endomembrane system. Distinguishing these vesicles functionally and molecularly represents a major challenge. Intracellular nanovesicles (INVs) are a large class of transport vesicles that likely comprises of multiple subtypes. Here, we define the INV proteome and find that it is molecularly heterogeneous, and enriched for transmembrane cargo molecules including integrins, transporters, and ATG9A, a lipid scramblase associated with autophagy. ATG9A is known to reside in 'ATG9 vesicles': small vesicles that contribute to autophagosome formation. Using in-cell vesicle capture assays we found that ATG9A, as well as other ATG9 vesicle cargos, were in INVs. Quantitative analysis showed that virtually all ATG9 vesicles are INVs, but that only ~20% of INVs are ATG9 vesicles, suggesting that ATG9 vesicles are in fact a subtype of INV, which we term ATG9A-flavor INVs. Finally, we show that perturbing ATG9A-flavor INVs impaired the autophagy response induced by starvation.","PeriodicalId":501590,"journal":{"name":"bioRxiv - Cell Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142189935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-12DOI: 10.1101/2024.09.10.612319
Shrena Chakraborty, Joanna Strachan, Kamila Schirmeisen, Laetitia Besse, Eve Mercier, Karine Freon, Haidao Zhang, Ning Zhao, Elizabeth Bayne, Sarah AE Lambert
The SUMO-targeted Ubiquitin ligase (STUbL) family is involved in multiple cellular processes via a wide range of mechanisms to maintain genome stability. One of the evolutionarily conserved functions of STUbL is to promote changes in the nuclear positioning of DNA lesions, targeting them to the nuclear periphery. In Schizossacharomyces pombe, the STUbL Slx8 is a regulator of SUMOylated proteins and promotes replication stress tolerance by counteracting the toxicity of SUMO conjugates. In order to study the dynamic dialectic between Ubiquitinylation and SUMOylation in the nuclear space of the S. pombe genome, we analyzed Slx8 localization. Unexpectedly, we did not detect replication stress-induced Slx8 foci. However, we discovered that Slx8 forms a single nuclear focus, enriched at the nuclear periphery, which marks both clustered centromeres at the spindle pole body and the silent mating type region. The formation of this single Slx8 focus requires the E3 SUMO ligase Pli1, poly-SUMOylation and the histone methyl transferase Clr4 that is responsible for the heterochromatin histone mark H3-K9 methylation. Finally, we established that Slx8 promotes centromere clustering and gene silencing at heterochromatin domains. Altogether, our data highlight evolutionarily conserved and functional relationships between STUbL and heterochromatin domains to promote gene silencing and nuclear organization.
{"title":"The fission yeast SUMO-targeted Ubiquitin Ligase Slx8 functionally associates with clustered centromeres and the silent mating type region at the nuclear periphery","authors":"Shrena Chakraborty, Joanna Strachan, Kamila Schirmeisen, Laetitia Besse, Eve Mercier, Karine Freon, Haidao Zhang, Ning Zhao, Elizabeth Bayne, Sarah AE Lambert","doi":"10.1101/2024.09.10.612319","DOIUrl":"https://doi.org/10.1101/2024.09.10.612319","url":null,"abstract":"The SUMO-targeted Ubiquitin ligase (STUbL) family is involved in multiple cellular processes via a wide range of mechanisms to maintain genome stability. One of the evolutionarily conserved functions of STUbL is to promote changes in the nuclear positioning of DNA lesions, targeting them to the nuclear periphery. In Schizossacharomyces pombe, the STUbL Slx8 is a regulator of SUMOylated proteins and promotes replication stress tolerance by counteracting the toxicity of SUMO conjugates. In order to study the dynamic dialectic between Ubiquitinylation and SUMOylation in the nuclear space of the S. pombe genome, we analyzed Slx8 localization. Unexpectedly, we did not detect replication stress-induced Slx8 foci. However, we discovered that Slx8 forms a single nuclear focus, enriched at the nuclear periphery, which marks both clustered centromeres at the spindle pole body and the silent mating type region. The formation of this single Slx8 focus requires the E3 SUMO ligase Pli1, poly-SUMOylation and the histone methyl transferase Clr4 that is responsible for the heterochromatin histone mark H3-K9 methylation. Finally, we established that Slx8 promotes centromere clustering and gene silencing at heterochromatin domains. Altogether, our data highlight evolutionarily conserved and functional relationships between STUbL and heterochromatin domains to promote gene silencing and nuclear organization.","PeriodicalId":501590,"journal":{"name":"bioRxiv - Cell Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142189933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1101/2024.09.09.612149
HS Vincent Chen, Chuanyu Wei, Shing Fai Chan, Ardan M Saguner, Corinna B Brunckhorst, Firat Duru, Joseph E. Marine, Cynthia A. James, Hugh Calkins, Daniel Judge, Weinian Shou
Background: Pathological fibrosis is a major finding in cardiovascular diseases and can result in arrhythmia and heart failure. Desmosome gene mutations can lead to arrhythmogenic cardiomyopathy (ACM). Among ACM, pathogenic desmoplakin (DSP) variants cause a distinctive cardiomyopathy with excessive cardiac fibrosis that could precede ventricular dysfunction. DSP variants are also linked to other fibrotic diseases. Whether DSP plays any role in pathological fibrosis remain unknown. Methods: Mesenchymal stromal cells (MSCs) are resident fibroblast-like cells that are responsible for fibrogenesis in most organs, including hearts. We first used unbiased genome-wide analyses to generate cardiac fibroblasts-like, induced pluripotent stem cell-derived MSCs from normal donors and ACM patients with DSP mutations. We then studied the fibrogenic responses of cardiac MSCs to transforming growth factor beta-1 (TGF-?1) using Western/Co-IP, autophagy assay, gene knockdowns/over-expressions, genomic analyses, mouse DSP knockdown models, immunostaining, and qPCR. Results: TGF?1 induced excessive accumulations of vimentin (VIM)/fibrillar collagens, and over-activated fibrotic genes in DSP-mutant MSCs when compared to normal MSCs. In normal MSCs, VIMs bind to wild-type DSP during normal fibrogenesis after TGF?1. DSP-mutant MSCs exhibited a haploinsufficient phenotype with increased DSP-unbound VIMs that sequestered beclin-1 (BECN1) from activating autophagy and caveolin-1 (CAV1)-mediated endocytosis. Decreased autophagy caused collagen accumulations and diminished CAV1 endocytosis resulted in abnormal CAV1 plaque formation that over-activated fibrotic genes [COL1A1, COL3A1, and fibronectin (FN)] via heightened p38 activities after TGF?1. Genome-wide analysis and DSP knockdown in mouse fibroblasts confirmed this novel role of DSP mutations in pathological fibrosis. Overexpression of VIM-binding domains of DSP could suppress pathological fibrosis by increasing collagen autophagic degradation and decreasing fibrotic gene expressions. Conclusions: Our data reveal that DSP deficiency in MSCs/fibroblasts leads to exaggerated fibrogenesis in DSP-cardiomyopathy by decreasing BECN1 availability for autophagy and CAV1-endocytosis. Overexpression of VIM binding domains of DSP could be a new strategy to treat pathological fibrosis.
{"title":"Desmoplakin mutations in cardiac fibroblasts cause TGF?1-mediated pathological fibrogenesis in desmoplakin cardiomyopathy via beclin-1 regulation","authors":"HS Vincent Chen, Chuanyu Wei, Shing Fai Chan, Ardan M Saguner, Corinna B Brunckhorst, Firat Duru, Joseph E. Marine, Cynthia A. James, Hugh Calkins, Daniel Judge, Weinian Shou","doi":"10.1101/2024.09.09.612149","DOIUrl":"https://doi.org/10.1101/2024.09.09.612149","url":null,"abstract":"Background: Pathological fibrosis is a major finding in cardiovascular diseases and can result in arrhythmia and heart failure. Desmosome gene mutations can lead to arrhythmogenic cardiomyopathy (ACM). Among ACM, pathogenic desmoplakin (DSP) variants cause a distinctive cardiomyopathy with excessive cardiac fibrosis that could precede ventricular dysfunction. DSP variants are also linked to other fibrotic diseases. Whether DSP plays any role in pathological fibrosis remain unknown. Methods: Mesenchymal stromal cells (MSCs) are resident fibroblast-like cells that are responsible for fibrogenesis in most organs, including hearts. We first used unbiased genome-wide analyses to generate cardiac fibroblasts-like, induced pluripotent stem cell-derived MSCs from normal donors and ACM patients with DSP mutations. We then studied the fibrogenic responses of cardiac MSCs to transforming growth factor beta-1 (TGF-?1) using Western/Co-IP, autophagy assay, gene knockdowns/over-expressions, genomic analyses, mouse DSP knockdown models, immunostaining, and qPCR. Results: TGF?1 induced excessive accumulations of vimentin (VIM)/fibrillar collagens, and over-activated fibrotic genes in DSP-mutant MSCs when compared to normal MSCs. In normal MSCs, VIMs bind to wild-type DSP during normal fibrogenesis after TGF?1. DSP-mutant MSCs exhibited a haploinsufficient phenotype with increased DSP-unbound VIMs that sequestered beclin-1 (BECN1) from activating autophagy and caveolin-1 (CAV1)-mediated endocytosis. Decreased autophagy caused collagen accumulations and diminished CAV1 endocytosis resulted in abnormal CAV1 plaque formation that over-activated fibrotic genes [COL1A1, COL3A1, and fibronectin (FN)] via heightened p38 activities after TGF?1. Genome-wide analysis and DSP knockdown in mouse fibroblasts confirmed this novel role of DSP mutations in pathological fibrosis. Overexpression of VIM-binding domains of DSP could suppress pathological fibrosis by increasing collagen autophagic degradation and decreasing fibrotic gene expressions. Conclusions: Our data reveal that DSP deficiency in MSCs/fibroblasts leads to exaggerated fibrogenesis in DSP-cardiomyopathy by decreasing BECN1 availability for autophagy and CAV1-endocytosis. Overexpression of VIM binding domains of DSP could be a new strategy to treat pathological fibrosis.","PeriodicalId":501590,"journal":{"name":"bioRxiv - Cell Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1101/2024.09.09.612143
Brooke L O'Donnell, Dan Stefan, Yu-Hsin Chiu, Michael Zeitz, Justin Tang, Danielle Johnston, Stephanie Leighton, Carlijn Van Kessell, Kevin Barr, Laszlo Gyenis, Taylor Freeman, John J Kelly, Samar Sayedyahossein, David W Litchfield, Kathryn Roth, James W Smyth, Matthew Hebb, John Ronald, Douglas A Bayliss, Silvia Penuela
Pannexin 1 (PANX1) is upregulated in many cancers, where its activity and signalling promote tumorigenic properties. Here, we report a novel ~25 kDa isoform of human PANX1 (hPANX1-25K) which lacks the N-terminus and was detected in several human cancer cell lines including melanoma, osteosarcoma,breast cancer and glioblastoma multiforme. This isoform was increased upon hPANX1 CRISPR/Cas9 deletion targeting the first exon near M1, suggesting a potential alternative translation initiation (ATI) site. hPANX1-25K was confirmed to be a hPANX1 isoform via mass spectrometry, can be N-linked glycosylated at N254, and can interact with both β-catenin and full length hPANX1. A double deletion of hPANX1 and hPANX1-25K reduces cell growth and viability in cancer cells. hPANX1-25K is prevalent throughout melanoma progression, and its levels are increased in squamous cell carcinoma cells and patient-derived tumours, compared to keratinocytes and normal skin controls, indicating that it may be differentially regulated in normal and cancer cells.
{"title":"Novel Pannexin 1 isoform is increased in cancer","authors":"Brooke L O'Donnell, Dan Stefan, Yu-Hsin Chiu, Michael Zeitz, Justin Tang, Danielle Johnston, Stephanie Leighton, Carlijn Van Kessell, Kevin Barr, Laszlo Gyenis, Taylor Freeman, John J Kelly, Samar Sayedyahossein, David W Litchfield, Kathryn Roth, James W Smyth, Matthew Hebb, John Ronald, Douglas A Bayliss, Silvia Penuela","doi":"10.1101/2024.09.09.612143","DOIUrl":"https://doi.org/10.1101/2024.09.09.612143","url":null,"abstract":"Pannexin 1 (PANX1) is upregulated in many cancers, where its activity and signalling promote tumorigenic properties. Here, we report a novel ~25 kDa isoform of human PANX1 (hPANX1-25K) which lacks the N-terminus and was detected in several human cancer cell lines including melanoma, osteosarcoma,breast cancer and glioblastoma multiforme. This isoform was increased upon hPANX1 CRISPR/Cas9 deletion targeting the first exon near M1, suggesting a potential alternative translation initiation (ATI) site. hPANX1-25K was confirmed to be a hPANX1 isoform via mass spectrometry, can be N-linked glycosylated at N254, and can interact with both β-catenin and full length hPANX1. A double deletion of hPANX1 and hPANX1-25K reduces cell growth and viability in cancer cells. hPANX1-25K is prevalent throughout melanoma progression, and its levels are increased in squamous cell carcinoma cells and patient-derived tumours, compared to keratinocytes and normal skin controls, indicating that it may be differentially regulated in normal and cancer cells.","PeriodicalId":501590,"journal":{"name":"bioRxiv - Cell Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142189952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1101/2024.09.11.612465
Sun K Kim, Stephen Rogers, Wen Lu, Brad S. Lee, Vladimir I Gelfand
Microtubule (MT) regulation is essential for oocyte development. In Drosophila, MT stability, polarity, abundance, and orientation undergo dynamic changes across developmental stages. In our effort to identify novel microtubule-associated proteins (MAPs) that regulate MTs in the Drosophila ovary, we identified a previously uncharacterized gene, CG18190, encoding a novel MT end-binding (EB) protein, which we propose to name EB-SUN. We show that EB-SUN colocalizes with EB1 at growing microtubule plus-ends in Drosophila S2 cells. Tissue-specific and developmental expression profiles from Paralog Explorer reveal that EB-SUN is predominantly expressed in the ovary and early embryos, while EB1 is ubiquitously expressed. Furthermore, as early as oocyte determination, EB-SUN comets are highly concentrated in oocytes during oogenesis. EB-SUN knockout (KO) results in a decrease in MT density at the onset of mid-oogenesis (Stage 7) and delays oocyte growth during late mid-oogenesis (Stage 9). Combining EB-SUN KO with EB1 knockdown (KD) in germ cells significantly further reduced MT density at Stage 7. Notably, all eggs from EB-SUN KO/EB1 KD females fail to hatch, unlike single gene depletion, suggesting a functional redundancy between these two EB proteins during embryogenesis. Our findings indicate that EB-SUN and EB1 play distinct roles during early embryogenesis.
{"title":"EB-SUN, a New Microtubule Plus-End Tracking Protein in Drosophila.","authors":"Sun K Kim, Stephen Rogers, Wen Lu, Brad S. Lee, Vladimir I Gelfand","doi":"10.1101/2024.09.11.612465","DOIUrl":"https://doi.org/10.1101/2024.09.11.612465","url":null,"abstract":"Microtubule (MT) regulation is essential for oocyte development. In Drosophila, MT stability, polarity, abundance, and orientation undergo dynamic changes across developmental stages. In our effort to identify novel microtubule-associated proteins (MAPs) that regulate MTs in the Drosophila ovary, we identified a previously uncharacterized gene, CG18190, encoding a novel MT end-binding (EB) protein, which we propose to name EB-SUN. We show that EB-SUN colocalizes with EB1 at growing microtubule plus-ends in Drosophila S2 cells. Tissue-specific and developmental expression profiles from Paralog Explorer reveal that EB-SUN is predominantly expressed in the ovary and early embryos, while EB1 is ubiquitously expressed. Furthermore, as early as oocyte determination, EB-SUN comets are highly concentrated in oocytes during oogenesis. EB-SUN knockout (KO) results in a decrease in MT density at the onset of mid-oogenesis (Stage 7) and delays oocyte growth during late mid-oogenesis (Stage 9). Combining EB-SUN KO with EB1 knockdown (KD) in germ cells significantly further reduced MT density at Stage 7. Notably, all eggs from EB-SUN KO/EB1 KD females fail to hatch, unlike single gene depletion, suggesting a functional redundancy between these two EB proteins during embryogenesis. Our findings indicate that EB-SUN and EB1 play distinct roles during early embryogenesis.","PeriodicalId":501590,"journal":{"name":"bioRxiv - Cell Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142189957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1101/2024.09.11.612480
Victoria Holmes, Morgan M C Ricci, Claire C Weckerly, Michael Worcester, Gerald R Hammond
Genetically encoded lipid biosensors are essential cell biological tools. They are the only technique that provide real time, spatially resolved kinetic data for lipid dynamics in living cells. Despite clear strengths, these tools also carry significant drawbacks; most notably, lipid molecules bound to biosensors cannot engage with their effectors, causing inhibition. Here, we show that although PI 3-kinase (PI3K)-mediated activation of Akt is not significantly reduced in a cell population transfected with a PH-Akt1 PIP3/PI(3,4)P2 biosensor, single cells expressing the PH-Akt at visible levels (used for live-cell imaging) have no activated Akt at all. Tagging endogenous AKT1 with neonGreen at its genomic locus reveals its EGF-mediated translocation to the plasma membrane, accumulating at densities of ~0.3 molecules/μm2. Co-transfection with the PH-Akt biosensor or other PIP3 biosensors completely blocks this translocation, despite robust recruitment of the biosensors. A partial inhibition is even observed with PI(3,4)P2-selective biosensor. However, we found that expressing lipid biosensors at low levels, comparable with those of endogenous AKT, produced no such inhibition. Helpfully, these single-molecule biosensors revealed improved dynamic range and kinetic fidelity compared with over-expressed biosensor. This approach represents a less invasive way to probe spatiotemporal dynamics of the PI3K pathway in living cells.
{"title":"Single molecule Lipid Biosensors Mitigate Inhibition of Endogenous Effector Proteins","authors":"Victoria Holmes, Morgan M C Ricci, Claire C Weckerly, Michael Worcester, Gerald R Hammond","doi":"10.1101/2024.09.11.612480","DOIUrl":"https://doi.org/10.1101/2024.09.11.612480","url":null,"abstract":"Genetically encoded lipid biosensors are essential cell biological tools. They are the only technique that provide real time, spatially resolved kinetic data for lipid dynamics in living cells. Despite clear strengths, these tools also carry significant drawbacks; most notably, lipid molecules bound to biosensors cannot engage with their effectors, causing inhibition. Here, we show that although PI 3-kinase (PI3K)-mediated activation of Akt is not significantly reduced in a cell population transfected with a PH-Akt1 PIP3/PI(3,4)P2 biosensor, single cells expressing the PH-Akt at visible levels (used for live-cell imaging) have no activated Akt at all. Tagging endogenous AKT1 with neonGreen at its genomic locus reveals its EGF-mediated translocation to the plasma membrane, accumulating at densities of ~0.3 molecules/μm2. Co-transfection with the PH-Akt biosensor or other PIP3 biosensors completely blocks this translocation, despite robust recruitment of the biosensors. A partial inhibition is even observed with PI(3,4)P2-selective biosensor. However, we found that expressing lipid biosensors at low levels, comparable with those of endogenous AKT, produced no such inhibition. Helpfully, these single-molecule biosensors revealed improved dynamic range and kinetic fidelity compared with over-expressed biosensor. This approach represents a less invasive way to probe spatiotemporal dynamics of the PI3K pathway in living cells.","PeriodicalId":501590,"journal":{"name":"bioRxiv - Cell Biology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142189960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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