Pub Date : 2024-05-02DOI: 10.1007/s00401-024-02727-9
Nurun N. Fancy, Amy M. Smith, Alessia Caramello, Stergios Tsartsalis, Karen Davey, Robert C. J. Muirhead, Aisling McGarry, Marion H. Jenkyns, Eleonore Schneegans, Vicky Chau, Michael Thomas, Sam Boulger, To Ka Dorcas Cheung, Emily Adair, Marianna Papageorgopoulou, Nanet Willumsen, Combiz Khozoie, Diego Gomez-Nicola, Johanna S. Jackson, Paul M. Matthews
Aging is associated with cell senescence and is the major risk factor for AD. We characterized premature cell senescence in postmortem brains from non-diseased controls (NDC) and donors with Alzheimer’s disease (AD) using imaging mass cytometry (IMC) and single nuclear RNA (snRNA) sequencing (> 200,000 nuclei). We found increases in numbers of glia immunostaining for galactosidase beta (> fourfold) and p16INK4A (up to twofold) with AD relative to NDC. Increased glial expression of genes related to senescence was associated with greater β-amyloid load. Prematurely senescent microglia downregulated phagocytic pathways suggesting reduced capacity for β-amyloid clearance. Gene set enrichment and pseudo-time trajectories described extensive DNA double-strand breaks (DSBs), mitochondrial dysfunction and ER stress associated with increased β-amyloid leading to premature senescence in microglia. We replicated these observations with independent AD snRNA-seq datasets. Our results describe a burden of senescent glia with AD that is sufficiently high to contribute to disease progression. These findings support the hypothesis that microglia are a primary target for senolytic treatments in AD.
{"title":"Characterisation of premature cell senescence in Alzheimer’s disease using single nuclear transcriptomics","authors":"Nurun N. Fancy, Amy M. Smith, Alessia Caramello, Stergios Tsartsalis, Karen Davey, Robert C. J. Muirhead, Aisling McGarry, Marion H. Jenkyns, Eleonore Schneegans, Vicky Chau, Michael Thomas, Sam Boulger, To Ka Dorcas Cheung, Emily Adair, Marianna Papageorgopoulou, Nanet Willumsen, Combiz Khozoie, Diego Gomez-Nicola, Johanna S. Jackson, Paul M. Matthews","doi":"10.1007/s00401-024-02727-9","DOIUrl":"10.1007/s00401-024-02727-9","url":null,"abstract":"<div><p>Aging is associated with cell senescence and is the major risk factor for AD. We characterized premature cell senescence in postmortem brains from non-diseased controls (NDC) and donors with Alzheimer’s disease (AD) using imaging mass cytometry (IMC) and single nuclear RNA (snRNA) sequencing (> 200,000 nuclei). We found increases in numbers of glia immunostaining for galactosidase beta (> fourfold) and p16<sup>INK4A</sup> (up to twofold) with AD relative to NDC. Increased glial expression of genes related to senescence was associated with greater β-amyloid load. Prematurely senescent microglia downregulated phagocytic pathways suggesting reduced capacity for β-amyloid clearance. Gene set enrichment and pseudo-time trajectories described extensive DNA double-strand breaks (DSBs), mitochondrial dysfunction and ER stress associated with increased β-amyloid leading to premature senescence in microglia. We replicated these observations with independent AD snRNA-seq datasets. Our results describe a burden of senescent glia with AD that is sufficiently high to contribute to disease progression. These findings support the hypothesis that microglia are a primary target for senolytic treatments in AD.</p></div>","PeriodicalId":7012,"journal":{"name":"Acta Neuropathologica","volume":null,"pages":null},"PeriodicalIF":9.3,"publicationDate":"2024-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00401-024-02727-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140819274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Influenza-associated encephalopathy (IAE) is extremely acute in onset, with high lethality and morbidity within a few days, while the direct pathogenesis by influenza virus in this acute phase in the brain is largely unknown. Here we show that influenza virus enters into the cerebral endothelium and thereby induces IAE. Three-weeks-old young mice were inoculated with influenza A virus (IAV). Physical and neurological scores were recorded and temporal-spatial analyses of histopathology and viral studies were performed up to 72 h post inoculation. Histopathological examinations were also performed using IAE human autopsy brains. Viral infection, proliferation and pathogenesis were analyzed in cell lines of endothelium and astrocyte. The effects of anti-influenza viral drugs were tested in the cell lines and animal models. Upon intravenous inoculation of IAV in mice, the mice developed encephalopathy with brain edema and pathological lesions represented by micro bleeding and injured astrocytic process (clasmatodendrosis) within 72 h. Histologically, massive deposits of viral nucleoprotein were observed as early as 24 h post infection in the brain endothelial cells of mouse models and the IAE patients. IAV inoculated endothelial cell lines showed deposition of viral proteins and provoked cell death, while IAV scarcely amplified. Inhibition of viral transcription and translation suppressed the endothelial cell death and the lethality of mouse models. These data suggest that the onset of encephalopathy should be induced by cerebral endothelial infection with IAV. Thus, IAV entry into the endothelium, and transcription and/or translation of viral RNA, but not viral proliferation, should be the key pathogenesis of IAE.
{"title":"Viral entry and translation in brain endothelia provoke influenza-associated encephalopathy","authors":"Shihoko Kimura-Ohba, Mieko Kitamura, Yusuke Tsukamoto, Shigetoyo Kogaki, Shinsuke Sakai, Hiroaki Fushimi, Keiko Matsuoka, Makoto Takeuchi, Kyoko Itoh, Keiji Ueda, Tomonori Kimura","doi":"10.1007/s00401-024-02723-z","DOIUrl":"10.1007/s00401-024-02723-z","url":null,"abstract":"<div><p>Influenza-associated encephalopathy (IAE) is extremely acute in onset, with high lethality and morbidity within a few days, while the direct pathogenesis by influenza virus in this acute phase in the brain is largely unknown. Here we show that influenza virus enters into the cerebral endothelium and thereby induces IAE. Three-weeks-old young mice were inoculated with influenza A virus (IAV). Physical and neurological scores were recorded and temporal-spatial analyses of histopathology and viral studies were performed up to 72 h post inoculation. Histopathological examinations were also performed using IAE human autopsy brains. Viral infection, proliferation and pathogenesis were analyzed in cell lines of endothelium and astrocyte. The effects of anti-influenza viral drugs were tested in the cell lines and animal models. Upon intravenous inoculation of IAV in mice, the mice developed encephalopathy with brain edema and pathological lesions represented by micro bleeding and injured astrocytic process (clasmatodendrosis) within 72 h. Histologically, massive deposits of viral nucleoprotein were observed as early as 24 h post infection in the brain endothelial cells of mouse models and the IAE patients. IAV inoculated endothelial cell lines showed deposition of viral proteins and provoked cell death, while IAV scarcely amplified. Inhibition of viral transcription and translation suppressed the endothelial cell death and the lethality of mouse models. These data suggest that the onset of encephalopathy should be induced by cerebral endothelial infection with IAV. Thus, IAV entry into the endothelium, and transcription and/or translation of viral RNA, but not viral proliferation, should be the key pathogenesis of IAE.</p></div>","PeriodicalId":7012,"journal":{"name":"Acta Neuropathologica","volume":null,"pages":null},"PeriodicalIF":9.3,"publicationDate":"2024-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00401-024-02723-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140814435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease of the CNS characterized by the production of disease-specific autoantibodies against aquaporin-4 (AQP4) water channels. Animal model studies suggest that anti-AQP4 antibodies cause a loss of AQP4-expressing astrocytes, primarily via complement-dependent cytotoxicity. Nonetheless, several aspects of the disease remain unclear, including: how anti-AQP4 antibodies cross the blood–brain barrier from the periphery to the CNS; how NMOSD expands into longitudinally extensive transverse myelitis or optic neuritis; how multiphasic courses occur; and how to prevent attacks without depleting circulating anti-AQP4 antibodies, especially when employing B-cell-depleting therapies. To address these knowledge gaps, we conducted a comprehensive ‘stage-dependent’ investigation of immune cell elements in situ in human NMOSD lesions, based on neuropathological techniques for autopsied/biopsied CNS materials. The present study provided three major findings. First, activated or netting neutrophils and melanoma cell adhesion molecule-positive (MCAM+) helper T (TH) 17/cytotoxic T (TC) 17 cells are prominent, and the numbers of these correlate with the size of NMOSD lesions in the initial or early-active stages. Second, forkhead box P3-positive (FOXP3+) regulatory T (Treg) cells are recruited to NMOSD lesions during the initial, early-active or late-active stages, suggesting rapid suppression of proinflammatory autoimmune events in the active stages of NMOSD. Third, compartmentalized resident memory immune cells, including CD103+ tissue-resident memory T (TRM) cells with long-lasting inflammatory potential, are detected under “standby” conditions in all stages. Furthermore, CD103+ TRM cells express high levels of granzyme B/perforin-1 in the initial or early-active stages of NMOSD in situ. We infer that stage-dependent compartmentalized immune traits orchestrate the pathology of anti-AQP4 antibody-guided NMOSD in situ. Our work further suggests that targeting activated/netting neutrophils, MCAM+ TH17/TC17 cells, and CD103+ TRM cells, as well as promoting the expansion of FOXP3+ Treg cells, may be effective in treating and preventing relapses of NMOSD.
{"title":"Stage-dependent immunity orchestrates AQP4 antibody-guided NMOSD pathology: a role for netting neutrophils with resident memory T cells in situ","authors":"Akihiro Nakajima, Fumihiro Yanagimura, Etsuji Saji, Hiroshi Shimizu, Yasuko Toyoshima, Kaori Yanagawa, Musashi Arakawa, Mariko Hokari, Akiko Yokoseki, Takahiro Wakasugi, Kouichirou Okamoto, Hirohide Takebayashi, Chihiro Fujii, Kyoko Itoh, Yo-ichi Takei, Shinji Ohara, Mitsunori Yamada, Hitoshi Takahashi, Masatoyo Nishizawa, Hironaka Igarashi, Akiyoshi Kakita, Osamu Onodera, Izumi Kawachi","doi":"10.1007/s00401-024-02725-x","DOIUrl":"10.1007/s00401-024-02725-x","url":null,"abstract":"<div><p>Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease of the CNS characterized by the production of disease-specific autoantibodies against aquaporin-4 (AQP4) water channels. Animal model studies suggest that anti-AQP4 antibodies cause a loss of AQP4-expressing astrocytes, primarily via complement-dependent cytotoxicity. Nonetheless, several aspects of the disease remain unclear, including: how anti-AQP4 antibodies cross the blood–brain barrier from the periphery to the CNS; how NMOSD expands into longitudinally extensive transverse myelitis or optic neuritis; how multiphasic courses occur; and how to prevent attacks without depleting circulating anti-AQP4 antibodies, especially when employing B-cell-depleting therapies. To address these knowledge gaps, we conducted a comprehensive ‘stage-dependent’ investigation of immune cell elements in situ in human NMOSD lesions, based on neuropathological techniques for autopsied/biopsied CNS materials. The present study provided three major findings. First, activated or netting neutrophils and melanoma cell adhesion molecule-positive (MCAM<sup>+</sup>) helper T (T<sub>H</sub>) 17/cytotoxic T (T<sub>C</sub>) 17 cells are prominent, and the numbers of these correlate with the size of NMOSD lesions in the initial or early-active stages. Second, forkhead box P3-positive (FOXP3<sup>+</sup>) regulatory T (T<sub>reg</sub>) cells are recruited to NMOSD lesions during the initial, early-active or late-active stages, suggesting rapid suppression of proinflammatory autoimmune events in the active stages of NMOSD. Third, compartmentalized resident memory immune cells, including CD103<sup>+</sup> tissue-resident memory T (T<sub>RM</sub>) cells with long-lasting inflammatory potential, are detected under “standby” conditions in all stages. Furthermore, CD103<sup>+</sup> T<sub>RM</sub> cells express high levels of granzyme B/perforin-1 in the initial or early-active stages of NMOSD in situ. We infer that stage-dependent compartmentalized immune traits orchestrate the pathology of anti-AQP4 antibody-guided NMOSD in situ. Our work further suggests that targeting activated/netting neutrophils, MCAM<sup>+</sup> T<sub>H</sub>17/T<sub>C</sub>17 cells, and CD103<sup>+</sup> T<sub>RM</sub> cells, as well as promoting the expansion of FOXP3<sup>+</sup> T<sub>reg</sub> cells, may be effective in treating and preventing relapses of NMOSD.</p></div>","PeriodicalId":7012,"journal":{"name":"Acta Neuropathologica","volume":null,"pages":null},"PeriodicalIF":9.3,"publicationDate":"2024-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140642552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-24DOI: 10.1007/s00401-024-02730-0
Anastasia Geladaris, Sebastian Torke, Darius Saberi, Yasemin B. Alankus, Frank Streit, Sabrina Zechel, Christine Stadelmann-Nessler, Andreas Fischer, Ursula Boschert, Darius Häusler, Martin S. Weber
In multiple sclerosis (MS), persisting disability can occur independent of relapse activity or development of new central nervous system (CNS) inflammatory lesions, termed chronic progression. This process occurs early and it is mostly driven by cells within the CNS. One promising strategy to control progression of MS is the inhibition of the enzyme Bruton's tyrosine kinase (BTK), which is centrally involved in the activation of both B cells and myeloid cells, such as macrophages and microglia. The benefit of BTK inhibition by evobrutinib was shown as we observed reduced pro-inflammatory activation of microglia when treating chronic experimental autoimmune encephalomyelitis (EAE) or following the adoptive transfer of activated T cells. Additionally, in a model of toxic demyelination, evobrutinib-mediated BTK inhibition promoted the clearance of myelin debris by microglia, leading to an accelerated remyelination. These findings highlight that BTK inhibition has the potential to counteract underlying chronic progression of MS.
在多发性硬化症(MS)中,持续性残疾的发生可能与复发活动或新的中枢神经系统(CNS)炎性病变的发展无关,这被称为慢性进展。这一过程发生较早,主要由中枢神经系统内的细胞驱动。抑制布鲁顿酪氨酸激酶(BTK)是控制多发性硬化症进展的一种很有前景的策略,该酶主要参与 B 细胞和骨髓细胞(如巨噬细胞和小胶质细胞)的活化。在治疗慢性实验性自身免疫性脑脊髓炎(EAE)或活化T细胞收养性转移后,我们观察到小胶质细胞的促炎性活化减少,这证明了evobrutinib抑制BTK的益处。此外,在毒性脱髓鞘模型中,evobrutinib介导的BTK抑制促进了小胶质细胞对髓鞘碎片的清除,从而加速了髓鞘再形成。这些发现突出表明,抑制 BTK 有可能抵消多发性硬化症潜在的慢性进展。
{"title":"BTK inhibition limits microglia-perpetuated CNS inflammation and promotes myelin repair","authors":"Anastasia Geladaris, Sebastian Torke, Darius Saberi, Yasemin B. Alankus, Frank Streit, Sabrina Zechel, Christine Stadelmann-Nessler, Andreas Fischer, Ursula Boschert, Darius Häusler, Martin S. Weber","doi":"10.1007/s00401-024-02730-0","DOIUrl":"10.1007/s00401-024-02730-0","url":null,"abstract":"<div><p>In multiple sclerosis (MS), persisting disability can occur independent of relapse activity or development of new central nervous system (CNS) inflammatory lesions, termed chronic progression. This process occurs early and it is mostly driven by cells within the CNS. One promising strategy to control progression of MS is the inhibition of the enzyme Bruton's tyrosine kinase (BTK), which is centrally involved in the activation of both B cells and myeloid cells, such as macrophages and microglia. The benefit of BTK inhibition by evobrutinib was shown as we observed reduced pro-inflammatory activation of microglia when treating chronic experimental autoimmune encephalomyelitis (EAE) or following the adoptive transfer of activated T cells. Additionally, in a model of toxic demyelination, evobrutinib-mediated BTK inhibition promoted the clearance of myelin debris by microglia, leading to an accelerated remyelination. These findings highlight that BTK inhibition has the potential to counteract underlying chronic progression of MS.</p></div>","PeriodicalId":7012,"journal":{"name":"Acta Neuropathologica","volume":null,"pages":null},"PeriodicalIF":9.3,"publicationDate":"2024-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00401-024-02730-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140642714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-19DOI: 10.1007/s00401-024-02720-2
Evan Udine, Mariely DeJesus-Hernandez, Shulan Tian, Sofia Pereira das Neves, Richard Crook, NiCole A. Finch, Matthew C. Baker, Cyril Pottier, Neill R. Graff-Radford, Bradley F. Boeve, Ronald C. Petersen, David S. Knopman, Keith A. Josephs, Björn Oskarsson, Sandro Da Mesquita, Leonard Petrucelli, Tania F. Gendron, Dennis W. Dickson, Rosa Rademakers, Marka van Blitterswijk
The most prominent genetic cause of both amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) is a repeat expansion in the gene C9orf72. Importantly, the transcriptomic consequences of the C9orf72 repeat expansion remain largely unclear. Here, we used short-read RNA sequencing (RNAseq) to profile the cerebellar transcriptome, detecting alterations in patients with a C9orf72 repeat expansion. We focused on the cerebellum, since key C9orf72-related pathologies are abundant in this neuroanatomical region, yet TDP-43 pathology and neuronal loss are minimal. Consistent with previous work, we showed a reduction in the expression of the C9orf72 gene and an elevation in homeobox genes, when comparing patients with the expansion to both patients without the C9orf72 repeat expansion and control subjects. Interestingly, we identified more than 1000 alternative splicing events, including 4 in genes previously associated with ALS and/or FTLD. We also found an increase of cryptic splicing in C9orf72 patients compared to patients without the expansion and controls. Furthermore, we demonstrated that the expression level of select RNA-binding proteins is associated with cryptic splice junction inclusion. Overall, this study explores the presence of widespread transcriptomic changes in the cerebellum, a region not confounded by severe neurodegeneration, in post-mortem tissue from C9orf72 patients.
{"title":"Abundant transcriptomic alterations in the human cerebellum of patients with a C9orf72 repeat expansion","authors":"Evan Udine, Mariely DeJesus-Hernandez, Shulan Tian, Sofia Pereira das Neves, Richard Crook, NiCole A. Finch, Matthew C. Baker, Cyril Pottier, Neill R. Graff-Radford, Bradley F. Boeve, Ronald C. Petersen, David S. Knopman, Keith A. Josephs, Björn Oskarsson, Sandro Da Mesquita, Leonard Petrucelli, Tania F. Gendron, Dennis W. Dickson, Rosa Rademakers, Marka van Blitterswijk","doi":"10.1007/s00401-024-02720-2","DOIUrl":"10.1007/s00401-024-02720-2","url":null,"abstract":"<div><p>The most prominent genetic cause of both amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) is a repeat expansion in the gene <i>C9orf72</i>. Importantly, the transcriptomic consequences of the <i>C9orf72</i> repeat expansion remain largely unclear. Here, we used short-read RNA sequencing (RNAseq) to profile the cerebellar transcriptome, detecting alterations in patients with a <i>C9orf72</i> repeat expansion. We focused on the cerebellum, since key <i>C9orf72</i>-related pathologies are abundant in this neuroanatomical region, yet TDP-43 pathology and neuronal loss are minimal. Consistent with previous work, we showed a reduction in the expression of the <i>C9orf72</i> gene and an elevation in homeobox genes, when comparing patients with the expansion to both patients without the <i>C9orf72</i> repeat expansion and control subjects. Interestingly, we identified more than 1000 alternative splicing events, including 4 in genes previously associated with ALS and/or FTLD. We also found an increase of cryptic splicing in <i>C9orf72</i> patients compared to patients without the expansion and controls. Furthermore, we demonstrated that the expression level of select RNA-binding proteins is associated with cryptic splice junction inclusion. Overall, this study explores the presence of widespread transcriptomic changes in the cerebellum, a region not confounded by severe neurodegeneration, in post-mortem tissue from <i>C9orf72</i> patients.</p></div>","PeriodicalId":7012,"journal":{"name":"Acta Neuropathologica","volume":null,"pages":null},"PeriodicalIF":9.3,"publicationDate":"2024-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00401-024-02720-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140622792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-18DOI: 10.1007/s00401-024-02726-w
Esmat Karimi, Jochen Gohlke, Mila van der Borgh, Johan Lindqvist, Zaynab Hourani, Justin Kolb, Stacy Cossette, Michael W. Lawlor, Coen Ottenheijm, Henk Granzier
Nebulin, a critical protein of the skeletal muscle thin filament, plays important roles in physiological processes such as regulating thin filament length (TFL), cross-bridge cycling, and myofibril alignment. Pathogenic variants in the nebulin gene (NEB) cause NEB-based nemaline myopathy (NEM2), a genetically heterogeneous disorder characterized by hypotonia and muscle weakness, currently lacking curative therapies. In this study, we examined a cohort of ten NEM2 patients, each with unique pathogenic variants, aiming to understand their impact on mRNA, protein, and functional levels. Results show that pathogenic truncation variants affect NEB mRNA stability and lead to nonsense-mediated decay of the mutated transcript. Moreover, a high incidence of cryptic splice site activation was found in patients with pathogenic splicing variants that are expected to disrupt the actin-binding sites of nebulin. Determination of protein levels revealed patients with either relatively normal or markedly reduced nebulin. We observed a positive relation between the reduction in nebulin and a reduction in TFL, or reduction in tension (both maximal and submaximal tension). Interestingly, our study revealed a pathogenic duplication variant in nebulin that resulted in a four-copy gain in the triplicate region of NEB and a much larger nebulin protein and longer TFL. Additionally, we investigated the effect of Omecamtiv mecarbil (OM), a small-molecule activator of cardiac myosin, on force production of type 1 muscle fibers of NEM2 patients. OM treatment substantially increased submaximal tension across all NEM2 patients ranging from 87 to 318%, with the largest effects in patients with the lowest level of nebulin. In summary, this study indicates that post-transcriptional or post-translational mechanisms regulate nebulin expression. Moreover, we propose that the pathomechanism of NEM2 involves not only shortened but also elongated thin filaments, along with the disruption of actin-binding sites resulting from pathogenic splicing variants. Significantly, our findings highlight the potential of OM treatment to improve skeletal muscle function in NEM2 patients, especially those with large reductions in nebulin levels.
{"title":"Characterization of NEB pathogenic variants in patients reveals novel nemaline myopathy disease mechanisms and omecamtiv mecarbil force effects","authors":"Esmat Karimi, Jochen Gohlke, Mila van der Borgh, Johan Lindqvist, Zaynab Hourani, Justin Kolb, Stacy Cossette, Michael W. Lawlor, Coen Ottenheijm, Henk Granzier","doi":"10.1007/s00401-024-02726-w","DOIUrl":"10.1007/s00401-024-02726-w","url":null,"abstract":"<div><p>Nebulin, a critical protein of the skeletal muscle thin filament, plays important roles in physiological processes such as regulating thin filament length (TFL), cross-bridge cycling, and myofibril alignment. Pathogenic variants in the nebulin gene (<i>NEB</i>) cause NEB-based nemaline myopathy (NEM2), a genetically heterogeneous disorder characterized by hypotonia and muscle weakness, currently lacking curative therapies. In this study, we examined a cohort of ten NEM2 patients, each with unique pathogenic variants, aiming to understand their impact on mRNA, protein, and functional levels. Results show that pathogenic truncation variants affect <i>NEB</i> mRNA stability and lead to nonsense-mediated decay of the mutated transcript. Moreover, a high incidence of cryptic splice site activation was found in patients with pathogenic splicing variants that are expected to disrupt the actin-binding sites of nebulin. Determination of protein levels revealed patients with either relatively normal or markedly reduced nebulin. We observed a positive relation between the reduction in nebulin and a reduction in TFL, or reduction in tension (both maximal and submaximal tension). Interestingly, our study revealed a pathogenic duplication variant in nebulin that resulted in a four-copy gain in the triplicate region of NEB and a much larger nebulin protein and longer TFL. Additionally, we investigated the effect of Omecamtiv mecarbil (OM), a small-molecule activator of cardiac myosin, on force production of type 1 muscle fibers of NEM2 patients. OM treatment substantially increased submaximal tension across all NEM2 patients ranging from 87 to 318%, with the largest effects in patients with the lowest level of nebulin. In summary, this study indicates that post-transcriptional or post-translational mechanisms regulate nebulin expression. Moreover, we propose that the pathomechanism of NEM2 involves not only shortened but also elongated thin filaments, along with the disruption of actin-binding sites resulting from pathogenic splicing variants. Significantly, our findings highlight the potential of OM treatment to improve skeletal muscle function in NEM2 patients, especially those with large reductions in nebulin levels.</p></div>","PeriodicalId":7012,"journal":{"name":"Acta Neuropathologica","volume":null,"pages":null},"PeriodicalIF":9.3,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00401-024-02726-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140620549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-12DOI: 10.1007/s00401-024-02724-y
Anat O. Stemmer-Rachamimov, Liana Kozanno, Scott R. Plotkin, Justin T. Jordan, Joseph F. 3rd Rizzo
Neurofibromatosis type 1 (NF1) is a rare autosomal dominant disorder characterized by proliferation of cells from neural crest origin. The most common manifestations are cutaneous, neurologic, skeletal and ocular. The distinction of NF1 from other syndromes with multiple café-au-lait macules may be difficult in the pediatric age group, and ocular findings, especially Lisch nodules (i.e., melanocytic hamartomas on the irides), are a useful, early diagnostic tool. In recent years, novel ocular manifestations descriptively referred to as “choroidal abnormalities”, choroidal “hyperpigmented spots” and “retinal vascular abnormalities” have been recognized in NF1. Choroidal abnormalities (CA) appear as bright patchy nodules that can be best detected with near-infrared ocular coherence tomography imaging (NIR-OCT). Because of their high specificity and sensitivity for NF1, CA have been added as an ocular diagnostic criterion of NF1 as an alternative to Lisch nodules. Although CA are important ocular diagnostic criteria for NF1, the histologic correlates are controversial. We present the postmortem ocular pathology findings of an NF1 patient for whom clinical notes and ocular imaging were available. Findings in this patient included choroidal hyperpigmented spots on funduscopy and retinal vascular abnormalities, both of which have been reported to be closely associated with CA. Histologic examination of the eyes showed multiple clusters of melanocytes of varying sizes in the choroid. Pathologic review of 12 additional postmortem eyes from 6 NF1 patients showed multiple, bilateral choroidal melanocytic aggregates in all eyes. These findings suggest that the CA seen on NIR-OCT and the hyperpigmented spots seen clinically in NF1 patients are manifestations of multifocal choroidal melanocytic clusters, consistent with choroidal melanocytic hamartomas. Lisch nodules, often multiple, were present in all eyes with morphology that differed from the choroidal hamartomas. As such, although CA and Lisch nodules are melanocytic hamartomas, there are clear phenotypical differences in their morphologies.
{"title":"Histologic correlates of “Choroidal abnormalities” in Neurofibromatosis type 1 (NF1)","authors":"Anat O. Stemmer-Rachamimov, Liana Kozanno, Scott R. Plotkin, Justin T. Jordan, Joseph F. 3rd Rizzo","doi":"10.1007/s00401-024-02724-y","DOIUrl":"10.1007/s00401-024-02724-y","url":null,"abstract":"<div><p>Neurofibromatosis type 1 (NF1) is a rare autosomal dominant disorder characterized by proliferation of cells from neural crest origin. The most common manifestations are cutaneous, neurologic, skeletal and ocular. The distinction of NF1 from other syndromes with multiple café-au-lait macules may be difficult in the pediatric age group, and ocular findings, especially Lisch nodules (i.e., melanocytic hamartomas on the irides), are a useful, early diagnostic tool. In recent years, novel ocular manifestations descriptively referred to as “choroidal abnormalities”, choroidal “hyperpigmented spots” and “retinal vascular abnormalities” have been recognized in NF1. Choroidal abnormalities (CA) appear as bright patchy nodules that can be best detected with near-infrared ocular coherence tomography imaging (NIR-OCT). Because of their high specificity and sensitivity for NF1, CA have been added as an ocular diagnostic criterion of NF1 as an alternative to Lisch nodules. Although CA are important ocular diagnostic criteria for NF1, the histologic correlates are controversial. We present the postmortem ocular pathology findings of an NF1 patient for whom clinical notes and ocular imaging were available. Findings in this patient included choroidal hyperpigmented spots on funduscopy and retinal vascular abnormalities, both of which have been reported to be closely associated with CA. Histologic examination of the eyes showed multiple clusters of melanocytes of varying sizes in the choroid. Pathologic review of 12 additional postmortem eyes from 6 NF1 patients showed multiple, bilateral choroidal melanocytic aggregates in all eyes. These findings suggest that the CA seen on NIR-OCT and the hyperpigmented spots seen clinically in NF1 patients are manifestations of multifocal choroidal melanocytic clusters, consistent with choroidal melanocytic hamartomas. Lisch nodules, often multiple, were present in all eyes with morphology that differed from the choroidal hamartomas. As such, although CA and Lisch nodules are melanocytic hamartomas, there are clear phenotypical differences in their morphologies.</p></div>","PeriodicalId":7012,"journal":{"name":"Acta Neuropathologica","volume":null,"pages":null},"PeriodicalIF":9.3,"publicationDate":"2024-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140550356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-10DOI: 10.1007/s00401-024-02721-1
Prabesh Bhattarai, Tamil Iniyan Gunasekaran, Michael E. Belloy, Dolly Reyes-Dumeyer, Dörthe Jülich, Hüseyin Tayran, Elanur Yilmaz, Delaney Flaherty, Bengisu Turgutalp, Gauthaman Sukumar, Camille Alba, Elisa Martinez McGrath, Daniel N. Hupalo, Dagmar Bacikova, Yann Le Guen, Rafael Lantigua, Martin Medrano, Diones Rivera, Patricia Recio, Tal Nuriel, Nilüfer Ertekin-Taner, Andrew F. Teich, Dennis W. Dickson, Scott Holley, Michael Greicius, Clifton L. Dalgard, Michael Zody, Richard Mayeux, Caghan Kizil, Badri N. Vardarajan
The risk of developing Alzheimer’s disease (AD) significantly increases in individuals carrying the APOEε4 allele. Elderly cognitively healthy individuals with APOEε4 also exist, suggesting the presence of cellular mechanisms that counteract the pathological effects of APOEε4; however, these mechanisms are unknown. We hypothesized that APOEε4 carriers without dementia might carry genetic variations that could protect them from developing APOEε4-mediated AD pathology. To test this, we leveraged whole-genome sequencing (WGS) data in the National Institute on Aging Alzheimer's Disease Family Based Study (NIA-AD FBS), Washington Heights/Inwood Columbia Aging Project (WHICAP), and Estudio Familiar de Influencia Genetica en Alzheimer (EFIGA) cohorts and identified potentially protective variants segregating exclusively among unaffected APOEε4 carriers. In homozygous unaffected carriers above 70 years old, we identified 510 rare coding variants. Pathway analysis of the genes harboring these variants showed significant enrichment in extracellular matrix (ECM)-related processes, suggesting protective effects of functional modifications in ECM proteins. We prioritized two genes that were highly represented in the ECM-related gene ontology terms, (FN1) and collagen type VI alpha 2 chain (COL6A2) and are known to be expressed at the blood–brain barrier (BBB), for postmortem validation and in vivo functional studies. An independent analysis in a large cohort of 7185 APOEε4 homozygous carriers found that rs140926439 variant in FN1 was protective of AD (OR = 0.29; 95% CI [0.11, 0.78], P = 0.014) and delayed age at onset of disease by 3.37 years (95% CI [0.42, 6.32], P = 0.025). The FN1 and COL6A2 protein levels were increased at the BBB in APOEε4 carriers with AD. Brain expression of cognitively unaffected homozygous APOEε4 carriers had significantly lower FN1 deposition and less reactive gliosis compared to homozygous APOEε4 carriers with AD, suggesting that FN1 might be a downstream driver of APOEε4-mediated AD-related pathology and cognitive decline. To validate our findings, we used zebrafish models with loss-of-function (LOF) mutations in fn1b—the ortholog for human FN1. We found that fibronectin LOF reduced gliosis, enhanced gliovascular remodeling, and potentiated the microglial response, suggesting that pathological accumulation of FN1 could impair toxic protein clearance, which is ameliorated with FN1 LOF. Our study suggests that vascular deposition of FN1 is related to the pathogenicity of APOEε4, and LOF variants in FN1 may reduce APOEε4-related AD risk, providing novel clues to potential therapeutic interventions targeting the ECM to mitigate AD risk.
{"title":"Rare genetic variation in fibronectin 1 (FN1) protects against APOEε4 in Alzheimer’s disease","authors":"Prabesh Bhattarai, Tamil Iniyan Gunasekaran, Michael E. Belloy, Dolly Reyes-Dumeyer, Dörthe Jülich, Hüseyin Tayran, Elanur Yilmaz, Delaney Flaherty, Bengisu Turgutalp, Gauthaman Sukumar, Camille Alba, Elisa Martinez McGrath, Daniel N. Hupalo, Dagmar Bacikova, Yann Le Guen, Rafael Lantigua, Martin Medrano, Diones Rivera, Patricia Recio, Tal Nuriel, Nilüfer Ertekin-Taner, Andrew F. Teich, Dennis W. Dickson, Scott Holley, Michael Greicius, Clifton L. Dalgard, Michael Zody, Richard Mayeux, Caghan Kizil, Badri N. Vardarajan","doi":"10.1007/s00401-024-02721-1","DOIUrl":"10.1007/s00401-024-02721-1","url":null,"abstract":"<div><p>The risk of developing Alzheimer’s disease (AD) significantly increases in individuals carrying the <i>APOEε4</i> allele. Elderly cognitively healthy individuals with <i>APOEε4</i> also exist, suggesting the presence of cellular mechanisms that counteract the pathological effects of <i>APOEε4</i>; however, these mechanisms are unknown. We hypothesized that <i>APOEε4</i> carriers without dementia might carry genetic variations that could protect them from developing <i>APOEε4-</i>mediated AD pathology. To test this, we leveraged whole-genome sequencing (WGS) data in the National Institute on Aging Alzheimer's Disease Family Based Study (NIA-AD FBS), Washington Heights/Inwood Columbia Aging Project (WHICAP), and Estudio Familiar de Influencia Genetica en Alzheimer (EFIGA) cohorts and identified potentially protective variants segregating exclusively among unaffected <i>APOEε4</i> carriers. In homozygous unaffected carriers above 70 years old, we identified 510 rare coding variants. Pathway analysis of the genes harboring these variants showed significant enrichment in extracellular matrix (ECM)-related processes, suggesting protective effects of functional modifications in ECM proteins. We prioritized two genes that were highly represented in the ECM-related gene ontology terms, <i>(FN1)</i> and collagen type VI alpha 2 chain (<i>COL6A2</i>) and are known to be expressed at the blood–brain barrier (BBB), for postmortem validation and in vivo functional studies. An independent analysis in a large cohort of 7185 <i>APOEε4</i> homozygous carriers found that rs140926439 variant in <i>FN1</i> was protective of AD (OR = 0.29; 95% CI [0.11, 0.78], <i>P</i> = 0.014) and delayed age at onset of disease by 3.37 years (95% CI [0.42, 6.32], <i>P</i> = 0.025). The FN1 and COL6A2 protein levels were increased at the BBB in <i>APOEε4</i> carriers with AD. Brain expression of cognitively unaffected homozygous <i>APOEε4</i> carriers had significantly lower FN1 deposition and less reactive gliosis compared to homozygous <i>APOEε4</i> carriers with AD, suggesting that FN1 might be a downstream driver of <i>APOEε4</i>-mediated AD-related pathology and cognitive decline. To validate our findings, we used zebrafish models with loss-of-function (LOF) mutations in <i>fn1b</i>—the ortholog for human <i>FN1</i>. We found that fibronectin LOF reduced gliosis, enhanced gliovascular remodeling, and potentiated the microglial response, suggesting that pathological accumulation of FN1 could impair toxic protein clearance, which is ameliorated with <i>FN1</i> LOF. Our study suggests that vascular deposition of FN1 is related to the pathogenicity of <i>APOEε4</i>, and LOF variants in FN1 may reduce <i>APOEε4</i>-related AD risk, providing novel clues to potential therapeutic interventions targeting the ECM to mitigate AD risk.</p></div>","PeriodicalId":7012,"journal":{"name":"Acta Neuropathologica","volume":null,"pages":null},"PeriodicalIF":9.3,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00401-024-02721-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140547517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-07DOI: 10.1007/s00401-024-02713-1
Farshad Nassiri, Andrew Ajisebutu, Vikas Patil, Yasin Mamatjan, Jeff Liu, Justin Z. Wang, Mathew R. Voisin, Romina Nejad, Sheila Mansouri, Shirin Karimi, Ankur Chakravarthy, Eric Chen, Daniel D. De Carvalho, Kenneth Aldape, Gelareh Zadeh
Mutations in the pivotal metabolic isocitrate dehydrogenase (IDH) enzymes are recognized to drive the molecular footprint of diffuse gliomas, and patients with IDH mutant gliomas have overall favorable outcomes compared to patients with IDH wild-type tumors. However, survival still varies widely among patients with IDH mutated tumors. Here, we aimed to characterize molecular signatures that explain the range of IDH mutant gliomas. By integrating matched epigenome-wide methylome, transcriptome, and global metabolome data in 154 patients with gliomas, we identified a group of IDH mutant gliomas with globally altered metabolism that resembled IDH wild-type tumors. IDH-mutant gliomas with altered metabolism have significantly shorter overall survival from their IDH mutant counterparts that is not fully accounted for by recognized molecular prognostic markers of CDKN2A/B loss and glioma CpG Island Methylator Phenotype (GCIMP) status. IDH-mutant tumors with dysregulated metabolism harbored distinct epigenetic alterations that converged to drive proliferative and stem-like transcriptional profiles, providing a window to target novel dependencies in gliomas.
{"title":"Metabologenomic characterization uncovers a clinically aggressive IDH mutant glioma subtype","authors":"Farshad Nassiri, Andrew Ajisebutu, Vikas Patil, Yasin Mamatjan, Jeff Liu, Justin Z. Wang, Mathew R. Voisin, Romina Nejad, Sheila Mansouri, Shirin Karimi, Ankur Chakravarthy, Eric Chen, Daniel D. De Carvalho, Kenneth Aldape, Gelareh Zadeh","doi":"10.1007/s00401-024-02713-1","DOIUrl":"10.1007/s00401-024-02713-1","url":null,"abstract":"<div><p>Mutations in the pivotal metabolic isocitrate dehydrogenase (IDH) enzymes are recognized to drive the molecular footprint of diffuse gliomas, and patients with IDH mutant gliomas have overall favorable outcomes compared to patients with IDH wild-type tumors. However, survival still varies widely among patients with IDH mutated tumors. Here, we aimed to characterize molecular signatures that explain the range of IDH mutant gliomas. By integrating matched epigenome-wide methylome, transcriptome, and global metabolome data in 154 patients with gliomas, we identified a group of IDH mutant gliomas with globally altered metabolism that resembled IDH wild-type tumors. IDH-mutant gliomas with altered metabolism have significantly shorter overall survival from their IDH mutant counterparts that is not fully accounted for by recognized molecular prognostic markers of <i>CDKN2A/B</i> loss and glioma CpG Island Methylator Phenotype (GCIMP) status. IDH-mutant tumors with dysregulated metabolism harbored distinct epigenetic alterations that converged to drive proliferative and stem-like transcriptional profiles, providing a window to target novel dependencies in gliomas.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":7012,"journal":{"name":"Acta Neuropathologica","volume":null,"pages":null},"PeriodicalIF":9.3,"publicationDate":"2024-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140533914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}