Methyl-CpG binding protein 2 (MeCP2) is a chromatin-associated transcriptional regulator that modulates neuronal gene programs in response to environmental stimuli. Although MeCP2 has been implicated in stress responses and depression, its cell-type-specific functions within defined limbic circuits remain incompletely understood. Here, using a chronic restraint stress (CRS) model, we show that CRS selectively reduces MeCP2 protein in dopamine D2 receptor (D2R)-expressing medium spiny neurons in the nucleus accumbens (NAc). D2R-restricted MeCP2 knockdown was sufficient to increase immobility in the forced swim test, whereas Cre-dependent restoration of MeCP2 in NAc D2R neurons attenuated CRS-associated behavioral alterations across affective coping, anxiety-like behavior and reward sensitivity. Ex vivo multielectrode array recordings combined with optogenetic stimulation revealed that CRS-associated suppression of NAc activity was normalized toward control levels by MeCP2 restoration. To profile molecular correlates, we performed cell-type-resolved GeoMx digital spatial transcriptomics in virally labeled NAc D2R neurons and found that MeCP2 overexpression was associated with attenuation of CRS-linked transcriptional perturbations, prominently involving synaptic and neuronal communication-related programs. In parallel, we detected CRS-responsive molecular signatures in the ventral pallidum that shifted with NAc D2R-restricted MeCP2 restoration, although these downstream profiles are not projection-resolved. Collectively, our findings identify a D2R neuron-biased role for MeCP2 in the NAc and support the view that restoring MeCP2 in this cell population is associated with mitigation of CRS-induced depression-like phenotypes and accompanying circuit/transcriptomic signatures. Chronic restraint stress (CRS) reduces MeCP2 protein in nucleus accumbens (NAc) D2 receptor (D2R)-expressing neurons, suppressing activity- and synapse-related programs and promoting depressive-like behaviors. Cell-type-specific restoration of MeCP2 in NAc D2R neurons normalizes neuronal activity and attenuates behavioral deficits, accompanied by coordinated transcriptional shifts involving synaptic organization, glutamatergic signaling, potassium channel activity and cytoskeletal regulation. CRS-responsive molecular signatures in the ventral pallidum (VP) show partial normalization in association with MeCP2 upregulation (VP bulk ROIs). Together, these findings implicate MeCP2-dependent regulation of NAc D2R neuron state in stress-related outcomes.

The development of compounds triggering intestinal stem cells (ISCs) proliferation represents a promising strategy to alleviate irradiation (IR)-induced gastrointestinal syndrome. Here, cannabidiol (CBD)-a nonpsychotomimetic phytocannabinoid derived from the Cannabis sativa plant-was found to dramatically improve body weight loss of mice and stimulate Lgr5+ ISCs proliferation upon a lethal dose of IR. Using absolute quantitative lipidomics, we found that the dysregulation of fatty acids in crypts induced by IR was rescued by CBD, which was indispensable for ISCs regeneration. Integrative analysis of transcriptome and lipidomics unveiled the critical role of PPARα in regulating fatty acid β-oxidation (FAO) by transcriptionally upregulating Slc27a2 and Acox1. Further experiments showed that CBD could trigger the enrichment of Stat2 on the promoter region of Pparα, ultimately facilitating the FAO program and subsequent ISCs proliferation following IR exposure. In addition,THOC3 was identified as a direct target of CBD, which stabilized the THOC3 protein and substantially alleviated the IR-induced blockade of Stat2 mRNA nuclear export. This study reveals a connection between CBD-driven ISCs proliferation and the FAO program during IR damage, providing a promising avenue for IR-induced gastrointestinal syndrome treatment. The binding of CBD to THOC3 maintains its radiation stability, which then supports the nuclear export of Stat2 mRNA for the subsequent transactivation of Pparα. The upregulation of PPARα will ultimately stimulate the FAO program, thereby facilitating ISCs regeneration during IR exposure.

N-terminal (Nt) methionine formylation, once thought restricted to bacteria and organelles, is now recognized as a stress-inducible initiator modification in the eukaryotic cytosol. Under metabolic or environmental stress, mitochondrial methionyl-transfer RNA (tRNA) formyltransferase mislocalizes to the cytosol, generating formylated initiator tRNA (fMet-tRNAi) that initiates translation with N-formylmethionine (fMet). Nascent chains bearing Nt-fMet activate an fMet-directed ribosome-associated quality control checkpoint early in elongation, recruiting ribosome-splitting and disaggregation factors. Stalled complexes are routed to stress granules, conserving mRNA, translation machinery, and energy, while limiting aggregation. During prolonged stress, newly synthesized fMet proteins undergo maturation or selective degradation via the fMet/N-degron pathway. In mammals, E3 ligase TRIM52 acts as an Nt-fMet recognin, modulating apoptosis. Proteolytic clearance of cytosolic fMet substrates releases formylated peptides and free fMet, which are elevated in critical illness and activate formyl peptide receptors - linking translation surveillance to innate immune and inflammatory signaling in sepsis and age-related disease. Advances in N-terminomics and anti-fMet reagents now allow direct detection and quantification of cytosolic fMet proteoforms. This Review integrates bacterial and organellar paradigms with emerging cytosolic mechanisms, examines regulatory gating of Nt-formylation, and highlights therapeutic strategies to restore proteostasis and counter fMet-associated pathology.

Psoriasis is a chronic inflammatory disease characterized by dysregulated interactions between keratinocytes (KCs) and immune cells. However, the details of KCs orchestrating the immune cell infiltration, particularly for natural killer (NK) cells, remain unclear. Here NK cell infiltration is significantly increased in psoriatic skin lesions, and the application of anti-MHC-II treatment or knockout of H2-Ab1 in the epidermis dramatically reduces IMQ-mediated psoriatic dermatitis as well as the infiltration of NK cells through CXCL10 mediated by the ERK-CREB axis. Spatial transcriptomics reveal that NK cells coexist with KCs, driven by enhanced CXCL signaling, and epidermal H2-Ab1 deletion suppresses KC-NK cell communication. NK cells release granzyme B, inducing pyroptosis in adjacent GSDME-expressing KCs, contributing to the inflammatory response. NK cell depletion or Gsdme knockout reduces pyroptosis and alleviates psoriasis-like dermatitis. Multicolor immunohistochemistry confirms that epidermal MHC-II expression in psoriatic lesions correlates positively with NK cell, granzyme B and cleaved-GSDME levels. This study reveals that epidermal MHC-II attracts NK cells, triggering KC pyroptosis and remodeling the immune microenvironment in psoriasis, offering novel insights into its pathogenesis.

DNA topoisomerase II-binding protein 1 (TopBP1) plays a critical role in V(D)J recombination and DNA damage repair during B and T cell development. However, its role in the development of conventional dendritic cells (cDCs) remains unexplored. Mice with DC-specific depletion of TopBP1 (TopBP1cKO) exhibited accelerated tumor progression due to impaired anti-tumor immunity, which was characterized by cDC deficiency and pre-DC accumulation. The cDC deficiency observed in TopBP1cKO mice was not attributable to cell death resulting from accumulated DNA damage during DC development. Notably, Flt3 ligand (Flt3L)-mediated tumor immunotherapy was ineffective in TopBP1cKO tumor-bearing mice. Here we demonstrate that TopBP1 is required not only for the steady-state differentiation of total cDCs, including both cDC1 and cDC2, but also for the terminal differentiation of XCR1-CD24⁺ emergency progenitors (CD11c⁺cKit⁺) into XCR1⁺CD24⁺ cDC1s in response to Flt3L. Furthermore, TopBP1 was found to be essential for the function of the PU.1-IRF8 heterodimeric transcription factor complex, which is critical for cDC lineage specification. TopBP1 directly binds to this complex and facilitates the transcription of downstream target genes required for cDC development. These findings establish TopBP1 as a pivotal regulator of both steady-state and Flt3L-driven emergency cDC differentiation, particularly in guiding emergency progenitors into functional cDC1s. Our study highlights the previously unrecognized role of TopBP1 as a co-regulator of lineage-defining transcription factors and as a determinant of Flt3L-mediated anti-tumor efficacy.

Growth differentiation factor-15 (GDF15), a stress-responsive cytokine of the transforming growth factor-β superfamily, is elevated in cancer cachexia, chemotherapy-induced nausea, and hyperemesis gravidarum, making it both a biomarker and a therapeutic target. Here, we developed high-affinity GDF15 binders using an artificial intelligence-driven protein design framework. To achieve this, we systematically explored three complementary scaffold-generation strategies: scaffold grafting, diffusion-based de novo design, and scaffold-search and grafting, identifying distinct advantages - scaffold grafting rapidly optimized receptor-derived motifs to sub-nanomolar affinity; de novo diffusion produced topologically novel binders; and scaffold-search and grafting enabled access to concave site B of GDF15 by repurposing evolutionary structural analogs from natural complexes. The designed GDF15 binders were translated into two functional modalities. First, a one-step, wash-free luminescent biosensor was created by coupling a de novo binder to split-luciferase fragments, enabling the rapid and sensitive quantification of GDF15. Second, the highest-affinity binder was engineered as an Fc-fusion decoy receptor, thereby effectively neutralizing GDF15 signaling in cell-based assays (IC50 = 7.2 nM), demonstrating comparable in vitro potency to ponsegromab, a monoclonal antibody currently undergoing phase II clinical trials. Together, this work establishes a versatile artificial intelligence-driven binder design pipeline with broad potential for next-generation diagnostics and therapeutics in cancer cachexia and other GDF15-mediated diseases.

The comorbidity of overactive bladder (OAB) and irritable bowel syndrome (IBS) presents a major clinical challenge, with the underlying neural and microbial mechanisms of the gut-bladder axis poorly understood. Here we aimed to delineate the complete causal pathway from a specific gut microorganism to bladder dysfunction and validate it as a therapeutic target. We combined analysis of human OAB-IBS cohorts with a postinflammatory mouse model, integrating retrograde neuronal tracing, multiomics (16S rDNA and metabolomics), fecal microbiota transplantation, urodynamics, dorsal root ganglion (DRG) electrophysiology and pharmacological and/or surgical interventions. We first confirmed a direct anatomical link, identifying dichotomized DRG neurons co-innervating the colon and bladder. Patients with OAB-IBS and mice exhibited a shared gut dysbiosis characterized by Akkermansia muciniphila enrichment. This comorbidity occurred in the absence of local bladder inflammation or urinary colonization with A. muciniphila, confirming a functional, noninfectious mechanism. Fecal microbiota transplantation of A. muciniphila or patient microbiota causally exacerbated visceral hypersensitivity, the OAB phenotype and DRG hyperexcitability. Mechanistically, A. muciniphila enrichment shunted host tryptophan metabolism toward the serotonin (5-HT) pathway. The resulting excess 5-HT acted on specifically upregulated colonic 5-HT3a receptors to drive neuronal sensitization. Crucially, pharmacological blockade of the colonic 5-HT3a receptor or surgical severing of the mesenteric nerves reversed the bladder dysfunction and visceral hypersensitivity. Our findings delineate a novel pathway wherein A. muciniphila drives functional gut-bladder comorbidity by promoting a gut-derived serotonergic signal that sensitizes shared afferent neurons, establishing the gut-specific 5-HT3a receptor as a key, druggable therapeutic target.

Muscle-invasive bladder cancer (MIBC) presents with variable clinical and pathological features, leading to inconsistent responses to standard treatments such as neoadjuvant chemotherapy (NAC). Although transcriptome profiling has shown differences in NAC response, reliable predictors of treatment outcome remain elusive. Here this study aimed to improve NAC response prediction by integrating multicohort transcriptomic data and spatial protein expression profiles using machine learning, enabling precision diagnostics and therapeutic strategies. Transcriptome analysis from four independent cohorts (n = 399) using diverse gene classifiers revealed molecular features associated with NAC response, particularly genes involved in stress responses, immunity and cell adhesion. The clinical relevance of 74 markers was validated by digital pathology for analyzing spatial protein expression. The machine learning frameworks reduced complex transcriptome and digital pathology datasets to a clinically manageable number of biomarkers, yielding an optimal antibody panel for immunohistochemistry-based clinical diagnostics. Computational pathology-driven predictions of NAC response demonstrated a strong correlation with survival outcomes in patients with MIBC, highlighting their potential clinical utility. Mechanistically, targeting the KEAP1-NRF2 axis suppressed glutathione dynamics, proliferation, stemness features and invasiveness of cisplatin-resistant MIBC cells, thereby resensitizing them to cisplatin. Combination treatment with cisplatin and inhibitors targeting the KEAP1-NRF2 pathway markedly suppressed tumor growth in an orthotopic xenograft model. Therefore, this study integrates machine learning-based transcriptome profiling and digital pathology analysis to refine gene classifiers, provide a personalized and feasible framework for treatment decision-making, and overcome chemoresistance to improve therapeutic efficacy. This study integrates machine learning with transcriptome and digital pathology data to identify and validate predictive biomarkers for neoadjuvant chemotherapy response in muscle-invasive bladder cancer. The optimized biomarkers, along with a proposed antibody combination, may improve precision medicine approaches. The KEAP1-NRF2 pathway was identified as a potential therapeutic target.

Lactate has been recognized as a major fuel substrate and also a lactyl-group donor for histone lysine lactylation. Hepatocytes act as lactate-consuming cells owing the high oxidative capability especially during exercise, a primary nonpharmacological intervention for alleviating metabolic dysfunction-associated steatotic liver diseases including steatohepatitis (MASLD/MASH). However, little is known regarding how lactate links the metabolic-epigenetic axis in hepatocytes. Here we show that declined estrogen-related receptor α (ESRRA) expression occur in MASLD/MASH accompanied with elevated levels of lactate and histone lactylation, particularly H3K18la. Such dysregulation can be partially rescued by chronic exercise in aged mice or exacerbated by genetic ablation of hepatocyte ESRRA. Mechanistically, exercise-induced ESRRA/PPARGC1A facilitates lactate consumption through transcriptional regulation of lactate dehydrogenase B and glucose-6-phosphatase catalytic subunit 1, rewiring lactate from a lactyl donor to gluconeogenic precursor in hepatocytes. Hepatocyte-specific ESRRA overexpression counteracts MASLD/MASH progression in mice, rectifying aberrant H3K18la accumulation and its marked gene transcripts that are involved in liver pathology. Our findings reveal that ESRRA functions as an exercise executor linking metabolism with epigenetic modification, highlighting a gluconeogenic-epigenetic regulatory axis that could be fine-tuned to mitigate risk factors of MASLD/MASH such as aging, menopause, a sedentary lifestyle and malnutrition.