The FASEB Journal最新文献

Pathological cardiac hypertrophy is a major contributor to heart failure and is often accompanied by ferroptosis and mitochondrial dysfunction. However, the upstream transcriptional mechanisms governing these processes remain poorly defined. We performed integrative bioinformatics analysis using transverse aortic constriction (TAC)-induced hypertrophic heart datasets to identify mitochondria-related differentially expressed genes (MitoDEGs), followed by transcription factor prediction and experimental validation in both in vivo and in vitro models. Adeno-associated virus-mediated overexpression and knockdown strategies were used to assess the regulatory effects of Irx3 and its downstream target Etfa. We identified Etfa as a hub MitoDEG directly regulated by the transcription factor Irx3, which was significantly upregulated in hypertrophic hearts. Mechanistically, Irx3 directly bound to the Etfa promoter and restored Etfa expression in hypertrophic cardiomyocytes. Through integrated transcriptomic analysis, an angiotensin II-induced cardiomyocyte hypertrophy model, and a TAC mouse model, we demonstrate that the Irx3–Etfa axis attenuates hypertrophic remodeling by suppressing ferroptosis. In vitro, overexpression of Irx3 or Etfa alleviates cardiomyocyte hypertrophy and ferroptotic injury, whereas Etfa knockdown abolishes the protective effects of Irx3. In vivo, Irx3 overexpression improves cardiac function, reduces ferroptosis, and limits structural remodeling in TAC mice. These findings reveal a novel transcriptional pathway connecting mitochondrial metabolism to ferroptosis regulation and suggest the Irx3–Etfa axis as a promising therapeutic target for pathological cardiac hypertrophy.

The peroxisome proliferator-activated receptor gamma (PPARγ) signaling pathway plays a pivotal role in regulating the proliferation, apoptosis, inflammation, and metabolism of pulmonary arterial smooth muscle cells (PASMCs), suggesting its central involvement in the pathogenesis of pulmonary hypertension (PH). Although PPARγ agonists have shown promising therapeutic effects in preclinical models, their clinical translation remains challenging. Echinatin (Ecn), a natural flavonoid compound, has been reported to exhibit anti-inflammatory, antioxidant, and anti-proliferative properties by modulating multiple signaling pathways in various disease models. However, its therapeutic potential and mechanisms of action in PH remain unclear. This study systematically investigated the therapeutic effects and underlying mechanisms of Ecn in two established PH rat models: SuHx-PH and MCT-PH. The results demonstrated that Ecn significantly improved hemodynamic parameters, reduced right ventricular systolic pressure, alleviated right ventricular hypertrophy, and mitigated pulmonary vascular remodeling in both models. Transcriptomic analysis further revealed that Ecn activated the PPARγ signaling pathway and reduced oxidative stress in lung tissue. In vitro experiments showed that Ecn inhibited abnormal PASMC proliferation and migration while promoting apoptosis. Molecular docking and surface plasmon resonance experiments confirmed that Ecn specifically binds to the PPARγ ligand-binding domain and enhances its nuclear transcriptional activity. In conclusion, this study demonstrates that Ecn acts as a partial agonist of PPARγ, exhibiting strong binding affinity for the receptor and ameliorating hemodynamic abnormalities and pulmonary vascular remodeling in experimental PH models. These findings provide a robust experimental foundation for considering Ecn as a potential therapeutic agent for PH and offer valuable insights for the development of PPARγ-targeted therapies.

ATP-dependent chromatin remodeling proteins are essential for regulating gene expression and chromosome function in both invertebrate and vertebrate species. However, the precise manner in which these proteins influence mammalian embryogenesis is not well understood. Recent studies have shown that the chromatin remodeling ATPase CHD4 plays a role in forming a functional trophectoderm and in blastocyst implantation in mice. Nevertheless, more research is needed to clarify the species-specific function of CHD4. Here, we demonstrate that depleting CHD4 in bovine embryos results in failure to form blastocyst and developmental arrest at the 16-32-cell stage, when CHD4 protein increases dramatically. We compared transcript levels in 16-cell embryos to identify the consequences of CHD4 loss. This analysis revealed 652 differentially expressed genes, a substantial proportion of which were developmental genes. ATAC-seq further revealed that differential gene expression was closely associated with altered chromatin accessibility. Immunofluorescence analyses revealed additional changes in histone modifications, including increased levels of H3K27ac and H3K9me3, in CHD4-depleted embryos. Notably, CHD4 depletion promotes the transcriptional activity of trophectoderm marker keratins (KRTs) before first lineage specification, accompanied by a global increase in chromatin accessibility. Furthermore, CHD4 depletion markedly reduced BRG1, a key ATP-dependent remodeler in the SWI/SNF complex. Collectively, our results reveal that CHD4 is necessary to restrict the expression of developmental genes and maintain the expression of BRG1 during early bovine development to ensure the transition from the 16-cell to the 32-cell stage.

Cardiac fibrosis (CF) is a major complication of myocardial infarction (MI), impairing myocardial function and leading to heart failure. Rosmarinic acid (RA) exhibits cardioprotective and antifibrotic properties, representing a promising therapeutic strategy for CF. This study evaluated the efficacy of exosomes derived from RA-primed adipose-derived stem cells (ADSCs), focusing on how RA-priming enhances their antioxidant and antifibrotic capacity against CF. An Isoproterenol (ISO)-induced myocardial injury model was established in vitro and in vivo. In vitro, H9C2 cardiomyoblasts were first injured with ISO and then treated with either exosomes (Exo) or RA-primed exosomes (RA-MSC-Exo) to assess cell viability and apoptosis. In vivo, 48 Wistar rats were divided into six groups: Control, Exo, RA-MSC-Exo, ISO, ISO + Exo, and ISO + RA-MSC-Exo. We assessed cardiac biomarkers (CK-MB and troponin I), reactive oxygen species (ROS), and total antioxidant capacity (TAC). We performed echocardiographic, molecular (real-time PCR and Western blotting), and histological analyses (Masson's trichrome staining) to evaluate cardiac function, fibrosis signaling pathways (NF-κB, TGF-β1, SMAD3), and collagen deposition. In vitro, both Exo and RA-MSC-Exo treatments significantly restored cell viability and reduced apoptosis in ISO-injured H9C2 cells. In vivo, both treatments significantly mitigated ISO-induced cardiac injury by reducing cardiac biomarkers, decreasing ROS production, and enhancing TAC levels. These interventions downregulated the expression of NF-κB, TGF-β1, Smad3, and Collagen I, leading to attenuated collagen deposition and improved cardiac function. Our study demonstrates that RA-primed exosomes effectively mitigate CF and improve cardiac function in an ISO-induced myocardial ischemia model. This targeted approach offers a promising therapeutic strategy for managing myocardial injury and its fibrotic complications.

The CRISPR–Cas system equips bacteria with adaptive immunity by storing fragments of invading nucleic acids in CRISPR loci and deploying Cas proteins to recognize and degrade matching sequences. In turn, bacteriophages have evolved small anti-CRISPR (Acr) that neutralize diverse CRISPR–Cas types. Acr genes are often co-encoded with transcriptional regulators called anti-CRISPR-associated (Aca) proteins, which suppress acr expression. Although 13 Aca families have been identified through bioinformatic analysis, detailed information on their target DNA-binding mechanisms and the inhibition of acr expression remains limited. Here, we report the high-resolution structure of Aca3 and delineate its DNA-binding interface. We demonstrate that Aca3 selectively recognizes inverted repeats upstream of its cognate acr gene, AcrIIC1. Mutational analyses of key helix–turn–helix residues confirm their essential roles in promoter engagement. Together, these results reveal the molecular basis for Aca3-mediated control of anti-CRISPR expression and expand our understanding of regulatory strategies that phages employ to modulate host CRISPR–Cas immunity.

Olfactory ensheathing cell (OEC) is one of the most promising cell candidates for the treatment of spinal cord injury (SCI). In recent years, the exosomes of OECs have shown neuroprotective properties in SCI. The aim of the present study was to examine whether exosomes derived from LPS preconditioned OEC could exhibit superior anti-inflammatory effect and also to investigate the underlying mechanisms. The extracellular vesicles derived from OECs under normal condition (N-EVs) and LPS preconditioned (L-EVs) were characterized with electron microscope, nanoparticle tracking analysis (NTA), and western blot. Metabolomics analysis was performed to analyze the metabolites in L-EVs treated microglia. Next, miRNA microarray analysis was used to compare the differential miRNAs in N-EVs and L-EVs. And gain and loss function experiments were performed to ascertain the efficacy of the anti-inflammatory mechanisms of L-EVs. Our results indicated that L-EVs could regulate microglia polarization from M1 phenotype to M2 phenotype. The metabolomics analysis showed that L-EVs treatment altered amino metabolism, and decreased the expression of Solute carrier family 7 member 11 (SLC7A11) in microglia. miRNA microarray analysis showed higher expression level of mir-1224 in L-EVs compared with N-EVs. The in vitro gain and loss function experiments demonstrated that mir-1224 promotes the degradation of CD44, and further decreases the expression of SLC7A11 in microglia which might involve in the cellular process of modulation microglial polarization. The extracellular vesicle derived from LPS preconditioned OECs exhibit a promising therapeutic paradigm for the treatment of SCI. And L-EVs alleviated neuroinflammation via modulating microglia polarization through mir-1224/CD44/SLC7A11 axis.

Diabetic cardiomyopathy (DCM) is characterized by metabolic dysregulation and progressive cardiac dysfunction, but the underlying molecular mechanisms remain incompletely understood. Emerging evidence suggests that 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2) may play an important role in DCM pathogenesis. This study reveals a novel regulatory mechanism involving SIRT5-mediated post-translational modification of HMGCS2 in DCM pathogenesis using high glucose-treated cardiomyocyte models and DCM mouse models. In DCM models, HMGCS2 was significantly upregulated and found to promote cardiomyocyte pyroptosis, cardiac dysfunction, and myocardial tissue damage. In contrast, SIRT5 exhibited cardioprotective effects under the same conditions. Moreover, SIRT5 overexpression reduced HMGCS2 succinylation while enhancing its ubiquitination and degradation in cardiomyocytes under high glucose conditions. Mechanistically, SIRT5 facilitated ubiquitin-mediated degradation of HMGCS2 at K118 by upregulating the E3 ubiquitin ligase PIAS4. In conclusion, SIRT5 mediated HMGCS2 desuccinylation while promoting PIAS4-dependent HMGCS2 ubiquitination and degradation. This study identified the SIRT5/PIAS4/HMGCS2 axis as a critical regulatory pathway in DCM, suggesting that targeting SIRT5 to influence HMGCS2 post-translational modifications might offer a novel therapeutic approach for DCM.