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Lamin A/C-regulated cysteine catabolic flux orchestrates cell fate through epigenome reprogramming
No full textSpatiotemporal changes in the nuclear lamina and cell metabolism shape cell fate, yet their interplay is poorly understood. Here, we identify lamin A/C as a key regulator of cysteine catabolic flux essential for proper cell fate and longevity. Its loss in naïve pluripotent stem cells upregulates CTH and CBS enzyme expression, thereby promoting de novo cysteine synthesis. Increased cysteine flux into acetyl-CoA fosters histone H3K9 and H3K27 acetylation, triggering a transition from naïve to primed pluripotency and abnormal cell fate and function. Conversely, the toxic gain-of-function mutation of Lmna, associated with premature aging, reduces CTH and CBS levels. This reroutes cysteine catabolic flux and alters the balance between H3K9 acetylation and methylation, crucially impacting germ layer formation and genome stability. Importantly, modulation of Cth and Cbs rescues the abnormal cell fate and function, restores the DNA damage repair capacity, and alleviates the senescent phenotype caused by lamin A/C mutations, highlighting the potential of modulating cell metabolism to mitigate epigenetic diseases
Structural studies suggest CCDC127 as a novel membrane contact site protein in the mitochondrial intermembrane space
Get PDFMitochondria feature a sophisticated membrane architecture, with a planar mitochondrial outer membrane (MOM) and a folded inner membrane (MIM). Due to the remarkable adaptability of mitochondria, a proteinaceous network in the intermembrane space (IMS) was proposed to confer both stability and flexibility. However, components of such scaffolds, tentatively termed the ’mitoskeleton’, have remained largely elusive. The mitochondrial contact site and organizing system (MICOS), a central organizer of mitochondrial membrane architecture, was suggested to participate in ’mitoskeleton’ formation. Here, we structurally characterize the coiled-coil domain-containing 127 (CCDC127) protein, a putative interactor of MICOS. We show that CCDC127’s amino-terminal transmembrane region is anchored in the MOM and the bulk soluble part exposed to the IMS. A crystal structure of CCDC127’s central coiled-coil displays a parallel dimer which further oligomerizes into tetramers. We demonstrate that the carboxy-terminal helical bundle (CHB) domain dimerizes to create a peripheral membrane-binding site. Supported by electron microscopy data, we propose a structural model of CCDC127 as intramitochondrial membrane contact site protein mediating the structural organization of the IMS as part of the ’mitoskeleton’
Altered cholesterol immunometabolism activates the macrophage NLRP3-inflammasome in lung fibrosis
No full textDEG with P-value
The deubiquitinase OTUD7B ameliorates central nervous system autoimmunity by inhibiting degradation of glial fibrillary acidic protein and astrocyte hyperinflammation
No full textAstrocytes are central to the pathogenesis of multiple sclerosis; however, their regulation by intrinsic post-translational ubiquitination and deubiquitination is unresolved. This study shows that the deubiquitinating enzyme OTUD7B in astrocytes confers protection against murine experimental autoimmune encephalomyelitis, a model of MS, by limiting neuroinflammation. RNA-sequencing of isolated astrocytes and spatial transcriptomics showed that in EAE OTUD7B downregulates the expression of chemokines in astrocytes of inflammatory lesions, which is associated with reduced recruitment of encephalitogenic CD4+ T cells. Furthermore, OTUD7B was essential for GFAP protein expression of astrocytes bordering inflammatory lesions. Mechanistically, OTUD7B (i) restricted TNF-induced chemokine production of astrocytes by sequential K63- and K48-deubiquitination of RIPK1 limiting NF-κB and MAPK activation and (ii) enabled GFAP protein expression by supporting GFAP mRNA expression and preventing its proteasomal degradation through K48-deubiquitination of GFAP. This dual action on TNF signaling and GFAP identifies astrocyte-intrinsic OTUD7B as a central inhibitor of astrocyte-mediated inflammation
OpenDVP: an experimental and computational framework for community-empowered deep visual proteomics
No full textLamin A/C-regulated cysteine catabolic flux modulates stem cell fate through epigenome reprogramming [ES_RNA_seq_G609G_LA_EXP2]
No full textSpatiotemporal changes in the nuclear lamina and cell metabolism shape cell fate, yet their interplay is poorly understood. Here, we identify lamin A/C as a key regulator of cysteine catabolic flux essential for proper cell fate and longevity. Its loss in naïve mouse pluripotent stem cells leads to upregulation of the cysteine generating and catabolizing enzymes, cystathionine γ-lyase (CTH) and cystathionine β-synthase (CBS), thereby promoting de novo cysteine synthesis. Increased cysteine flux into acetyl-CoA fosters histone H3K9 and H3K27 acetylation, triggering a transition from naïve to primed pluripotency and abnormal cell fate and function. Conversely, the toxic gain-of-function mutation of Lmna, encoding lamin A/C and associated with premature aging, reduces CTH and CBS levels. This reroutes cysteine catabolic flux and alters the balance between H3K9 acetylation and methylation, crucially impacting germ layer formation and genome stability. Importantly, modulation of Cth and Cbs rescues the abnormal cell fate and function, restores the DNA damage repair capacity, and alleviates the senescent phenotype caused by lamin A/C mutations, highlighting the potential of modulating cell metabolism to mitigate epigenetic diseases
Targeting MYCN upregulates L1CAM tumor antigen in MYCN-dysregulated neuroblastoma to increase CAR T cell efficacy
Get PDFCurrent treatment protocols have limited success against MYCN-amplified neuroblastoma. Adoptive T cell therapy presents an innovative strategy to improve cure rates. However, L1CAM-targeting CAR T cells achieved only limited response against refractory/relapsed neuroblastoma so far. We investigated how oncogenic MYCN levels influence tumor cell response to CAR T cells, as one possible factor limiting clinical success. A MYCN-inducible neuroblastoma cell model was created. L1CAM-CAR T cell effector function was assessed (activation markers, cytokine release, tumor cytotoxicity) after coculture with the model or MYCN-amplified neuroblastoma cell lines. RNA sequencing datasets characterizing the model were compared to publicly available RNA/proteomic datasets. MYCN-directed L1CAM regulation was explored using public ChIP-sequencing datasets. Synergism between CAR T cells and the indirect MYCN inhibitor, MLN8237, was assessed in vitro using the Bliss model and in vivo in an immunocompromised mouse model. Inducing high MYCN levels in the neuroblastoma cell model reduced L1CAM expression and, consequently, L1CAM-CAR T cell effector function in vitro. Primary neuroblastomas possessing high MYCN levels expressed lower levels of both the L1CAM transcript and L1CAM tumor antigen. MLN8237 treatment restored L1CAM tumor expression and L1CAM-CAR T cell effector function. Combining MLN8237 and L1CAM-CAR T cell treatment synergistically enhanced MYCN-overexpressing tumor cytotoxicity in vitro and in vivo concomitant with severe in vivo toxicity. We identify target antigen downregulation as source of resistance against L1CAM-CAR T cells in MYCN-driven neuroblastoma cells. These data suggest that L1CAM-CAR T cell therapy combined with pharmacological MYCN inhibition may benefit patients with MYCN-amplified neuroblastoma
Cognitive deficits in anti-LGI1 encephalitis are linked to immunotherapy-resistant white matter network changes
Get PDFBACKGROUND AND OBJECTIVES: Cognitive deficits represent a major long-term complication of anti–leucine-rich, glioma-inactivated 1 encephalitis (LGI1-E). Although severely affecting patient outcomes, the structural brain changes underlying these deficits remain poorly understood. In this study, we hypothesized a link between white matter (WM) networks and cognitive outcomes in LGI1-E. METHODS: In this cross-sectional study, we combined clinical assessments, comprehensive neuropsychological testing, diffusion tensor MRI, probabilistic WM tractography, and computational network analysis in patients with LGI1-E referred to Charité-Universitätsmedizin Berlin. Healthy individuals were recruited as control participants and matched to patients for age and sex with logistic regression propensity scores. RESULTS: Twenty-five patients with LGI1-E (mean age = 63 ± 12 years, 76% male) and 25 healthy controls were enrolled. Eighty-eight percent of patients presented persistent cognitive symptoms at postacute follow-up (median: 12 months from onset, interquartile range: 6–23 months)—despite treatment with immunotherapy and good overall recovery (modified Rankin Scale [mRS] score at peak illness vs postacute: z = −4.1, p < 0.001, median mRS score at postacute visit: 1). Neuroimaging revealed that WM networks in LGI1-E are characterized by (1) a systematic reduction in whole-brain connectivity (t = −2.16, p = 0.036, d = −0.61), (2) a cortico-subcortical hypoconnectivity cluster affecting both limbic and extralimbic brain systems, and (3) a “topological reorganization” marked by a bidirectional shift in the relative importance of individual brain regions in the WM network. The extent of this WM reorganization was strongly associated with long-term deficits of verbal memory (r = −0.56), attention (r = −0.55), and executive functions (r = −0.60, all pFDR = 0.017). DISCUSSION: Although traditionally viewed as a form of limbic encephalitis, our study characterizes LGI1-E as a “network disorder” that affects the whole brain. Structural reorganization of WM networks was linked to long-term and multidomain cognitive impairment, which was not prevented by immunotherapy. These findings highlight the need for closer monitoring and improved treatment strategies to mitigate long-term cognitive impairment in LGI1-E
