The FASEB Journal最新文献

β-hydroxybutyric acid (BHB), a key ketone body with energy substrate and epigenetic regulatory roles, has contradictory effects in pathological contexts. Intestinal ischemia–reperfusion (IIR) is a life threatening perioperative complication characterized by metabolic disorders and mitochondrial dysfunction, yet BHB's role in IIR remains unclear. Using C57BL/6 mouse IIR models and Caco2 cell hypoxia-reoxygenation (HR) models, we identified a pathogenic mechanism: IIR induced nearly 10-fold elevation of intestinal BHB, while ketolytic enzymes 3-hydroxybutyrate dehydrogenase 1 (BDH1) and 3-oxoacid CoA-transferase 1 (OXCT1) were significantly downregulated, blocking BHB's metabolic pathway. Exogenous BHB administration failed to protect the intestine; instead, it selectively inhibited expression of histone deacetylase 2 (HDAC2) (by 30%) and disrupted its nuclear binding to the Sirt7 promoter, promoting Sirt7 gene transcriptional activation (mRNA upregulated by 2-fold). This cascade exacerbated oxidative stress (reactive oxygen species increased by 2.7-fold), reduced adenosine triphosphate levels (by 20%), impaired mitochondrial biogenesis (decreased mitochondrial DNA copy number and mitochondrial transcription factor A (TFAM)/mitochondrial ribosomal proteins (MRPs) expression), and aggravated intestinal barrier dysfunction (Claudin-1 reduced and D-lactate elevated). Notably, HDAC2 overexpression or SIRT7 knockdown reversed these impairments. Our findings uncover a previously unrecognized role of BHB in exacerbating IIR injury via the HDAC2/SIRT7 pathway, providing new insights for protecting pathological intestinal tissues at ischemic risk and targeting mitochondrial biogenesis.

In cardiac dysfunction, intracellular Ca²⁺-dynamics are disrupted leading to leakage of Ca²⁺ from the sarcoplasmic reticulum (SR). This results in diminished cardiac contractility and impaired cardiac function. In cardiac tissue, the underlying molecular mechanisms responsible for RyR2-independent Ca²⁺-leak are poorly understood. Mitsugumin 23 (MG23) is an intracellular Ca²⁺-conducting ion channel located on endoplasmic/sarcoplasmic reticulum (ER/SR) and nuclear membranes. We propose that MG23 contributes to regulation of intracellular Ca²⁺-homeostasis, and that altered MG23 function may drive progression of cardiac dysfunction. The aim of this research was to investigate the role of MG23 in SR Ca²⁺-leak, and whether knockout of Mg23 protects the heart against pressure-overload induced left ventricular hypertrophy. Cardiac pressure-overload was induced in wild type (WT) and Mg23-knockout (KO) mice through subcutaneous Angiotensin II (AngII, 1.1 mg/kg/day) infusion via osmotic pump. After 10-day infusion, in vivo pressure-volume dynamics were measured by insertion of a pressure-volume catheter into the left ventricle. MG23 protein expression was assessed through Western blot analysis. Ventricular fibrosis and cardiomyocyte size were measured using histological and immunofluorescence approaches. Cardiomyocytes were isolated from WT and Mg23-KO hearts and intracellular Ca²⁺-dynamics assessed through live cell imaging using the Ca²⁺ indicator Fluo-4. AngII-induced cardiac pressure-overload increased expression of MG23 in WT mouse hearts. Knockout of Mg23 protected hearts against AngII-induced cardiac hypertrophy. Compared to WT animals, AngII treated Mg23-KO mice displayed a significant reduction in left ventricular fibrosis and displayed normal cardiac functioning. Overexpression of MG23 in the ventricular cell line H9C2, resulted in reduced SR Ca²⁺ store levels. In Mg23-KO hearts, no alteration in expression of key Ca²⁺-handling proteins was identified, but cardiomyocytes displayed altered Ca²⁺-spark profiles consistent with a role for MG23 in SR Ca²⁺-leak. MG23 plays a key role in driving Ca²⁺-dysregulation observed in the early pathological stages of pressure-overload induced heart failure.

Diabetic kidney disease (DKD) remains a major cause of chronic kidney failure; early diagnosis and mechanistic understanding are still inadequate. Urinary peptidomics offers a noninvasive strategy to identify key peptides correlated with DKD pathology and underlying mechanisms. We profiled urinary peptides using CE-MS/MS in three healthy controls, six diabetic patients without proteinuria, and 15 DKD patients. Target protein expression was validated in human kidney tissues and db/db mice. A synthetic peptide derived from complement factor B (CFB), identified as a top candidate, was functionally assessed in human and murine tubular cells, with its underlying mechanism explored via RNA-sequencing and pharmacological modulation. We identified 4331 urinary peptides, revealing a distinct DKD-specific signature enriched for proteins in the complement cascade and extracellular matrix pathways. Eight peptides strongly associated with disease severity and showed high diagnostic value. Among them, two bioactive peptides originating from CFB were significantly elevated in DKD. In vitro, the synthetic CFB peptide was efficiently taken up by tubular cells and attenuated fibrotic and oxidative stress. This nephroprotective effect was mediated through the suppression of the HIF-1α/glycolysis axis, as the effect was reversed by an HIF-1α activator (DMOG) and restored by a glycolysis inhibitor (2-DG). Our study delineates a DKD-specific urinary peptidome and identifies a bioactive CFB-derived peptide with potent antifibrotic and antioxidative properties. The findings support its potential as both a biomarker and a therapeutic candidate, highlighting an interplay between complement activation and metabolic dysregulation in the kidney.

Acute lung injury (ALI) and subsequent lung fibrosis involve critical roles of mitochondrial metabolism and immune inflammation. This study identified 10 hub mitochondrial-related differentially expressed genes (MitoDEGs) linked to these conditions through integrated bioinformatics screening and protein–protein interaction analysis. Functional enrichment associated these MitoDEGs with energy conversion, oxidative stress, and fatty acid metabolism in ALI and fibrosis. Immune infiltration analysis revealed prominent M1 macrophage infiltration in ALI, with significant correlations between each hub MitoDEG and immune cells. In vivo and in vitro experiments confirmed dynamic expression changes of key MitoDEGs, including Uqcrq and Ndufb6, alongside disturbances in mitochondrial, oxidative stress, and lipid metabolism pathways. Multiplex immunohistochemistry showed increased Ndufb6-positive alveolar epithelial cells during inflammatory infiltration. Functional studies demonstrated that Ndufb6 deficiency attenuated mitochondrial fragmentation, respiratory dysfunction, and oxidative stress under inflammatory and fibrotic stimuli. Preliminary evaluation also suggested the clinical relevance of Ndufb6 and Uqcrq. These findings highlight MitoDEGs at the intersection of mitochondrial metabolism and immune response, offering new mechanistic and therapeutic insights for ALI and post-injury lung fibrosis.

Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) is a recently recognized high-risk T lymphoblastic leukemia (T-ALL) subgroup, which is an immunophenotypic subtype with a high risk of infiltrating the central nervous system (CNS), leading to CNS leukemia and associated neurological and psychiatric symptoms. Prior studies have identified molecular mechanisms and pathways mediating ETP-ALL cell entry into the CNS. Nevertheless, CNS-directed therapy is associated with long-term adverse effects, encompassing neurocognitive impairments and secondary malignancies. Therefore, identification of the mechanisms underlying the effects of ETP-ALL infiltration on neurogenesis within the CNS is urgently needed. In this study, we observed elevated lactate levels and widespread lactate modification sites in ETP-ALL cells, especially with H3K18la levels significantly upregulated compared to non-ETP-ALL cells. We found that H3K18la levels in ETP-ALL impair human neural stem cells (hNSCs) self-renewal by suppressing proliferation and disrupting their differentiation capacity. Furthermore, we discovered that H3K18la inhibits neurogenesis through transcriptional activation of receptor activator of nuclear factor-kappa b ligand (RANKL). This research contributes to a deeper understanding of the mechanism of ETP-ALL's impact on neurogenesis of the CNS, potentially paving the way for novel therapeutic strategies targeting CNS ETP-ALL leukemia.

Osteoarthritis (OA) is a prevalent disease of the whole joint, in which synovial hyperplasia, inflammation, and fibrosis are important pathological manifestations. Melatonin (MT) possesses diverse biological activities and has shown promise in mitigating cartilage degradation in OA. However, further research is required to clarify MT's effects and mechanisms on OA synovium. Fibroblast-like synoviocytes (FLSs) were isolated and identified by immunofluorescence. Cell counting kit-8, EdU, flow cytometry, transwell, and wound healing assays were employed to assess the proliferation, DNA replication, cell cycle, apoptosis, and migration of FLSs. TGF-β1 was used to induce inflammation and fibrosis in FLSs. Protein and mRNA expression levels were evaluated using Western blot, enzyme-linked immunosorbent assay, immunofluorescence, and real-time quantitative PCR. Additionally, an OA rabbit model was established, and the pathological changes of synovium, synovial fluid, cartilage, and subchondral bone were investigated to assess the in vivo effects of MT on OA. The proliferation, DNA replication, and expression of proliferating cell nuclear antigen (PCNA) and c-Myc of FLSs were inhibited by MT intervention. MT arrested the cell cycle by inhibiting the expression of cyclin D1 and cyclin E1, induced apoptosis via down-regulating B-cell lymphoma-2 (Bcl-2) and up-regulating Bcl-2 associated X (Bax), and suppressed the migration by impairing vimentin expression in FLSs. Mechanistically, MT exerted these effects by regulating the Hippo/YAP and PI3K/AKT pathways. Moreover, MT ameliorated synovial hyperplasia, inflammation, fibrosis, and pathological changes in synovial fluid, as well as the destruction of cartilage and bone in the OA rabbit model. Our findings indicate that MT alleviates synovial pathological changes and delays OA progression, which is related to its ability to suppress aberrant FLS functions.

Gastric cancer ranks as the fifth most prevalent malignancy and the fifth leading cause of cancer-related mortality worldwide, with stomach adenocarcinoma (STAD) being the predominant pathological type. Despite a decline in STAD incidence in recent years, factors such as an aging population may contribute to an increase in future cases. Current clinical management of STAD primarily involves surgical resection, radiation, chemotherapy, and emerging immune checkpoint blockade (ICB) therapies. However, the limited efficacy of ICB monotherapy in most patients with STAD highlights the need for novel therapeutic targets. This study investigated the role of versican (VCAN) in STAD. Comprehensive analysis of multiple databases revealed significantly higher VCAN expression in STAD tissues compared to normal tissues, correlating with poor patient prognosis. Single-cell analysis further identified VCAN as predominantly secreted by cancer-associated fibroblasts (CAFs), especially the pan-pCAF subtype. CAFs with elevated VCAN levels promoted the proliferation, migration, and invasion of high-stemness adenocarcinoma cells via the MDK-NCL and MIF-CD74-CD44 signaling pathways, while also enhancing immune evasion and self-renewal. These results position VCAN as a potential new therapeutic target for STAD.