Luyang Yu

Excessive free radical production and dysregulated immune responses contribute to myocardial ischemia‐reperfusion (IR) injury. However, the mechanisms by which macrophages regulate reactive oxygen species (ROS) homeostasis and orchestrate immune responses during IR injury remain elusive. Here, we show that glutamate dehydrogenase 1 (GLUD1) expression is induced in monocytes from patients with acute myocardial infarction after interventional therapy and in cardiac‐recruited macrophages from mice subjected to IR injury. GLUD1‐deficient macrophages exacerbate IR injury by increasing mitochondrial ROS accumulation and amplifying pro‐inflammatory responses. Mechanistically, GLUD1 deficiency leads to mitochondrial ROS accumulation due to reduced NADPH/NADP ⁺ and GSH/GSSG ratios during IR injury. Elevated mitochondrial ROS inhibits PHD2 activity, stabilizing HIF‐1α and enhancing NF‐κB signaling, promoting the release of pro‐inflammatory factors and exacerbating myocardial damage. Systemic activation of GLUD1 or adoptive transfer of monocytes pre‐treated with a GLUD1 activator preserved cardiac function and mitigated IR injury. These findings highlight macrophage GLUD1 as a critical regulator of redox balance and immune homeostasis, presenting a promising therapeutic target for alleviating IR injury and preserving cardiac function.

Atherosclerosis is a chronic inflammatory disease in which the endothelial NLRP3 inflammasome cascade serves as a central mediator that promotes endothelial dysfunction, vascular inflammation, and lesion progression. A critical step for this cascade is the transcriptional upregulation of Caspase-1 and GSDMD during the inflammasome priming phase, yet the underlying mechanisms governing their expression in endothelial cells (ECs) remain largely unknown. Here we show that SENP1 is upregulated in the endothelium of human arteries with severe versus mild atherosclerosis and in mouse arteries with atherosclerotic versus healthy, correlating with elevated Caspase-1 and GSDMD expression. Consistently, SENP1 was induced by Ox-LDL in cultured ECs, confirming its responsiveness to pro-atherogenic stimuli. Endothelial-specific deletion of Senp1 attenuates atherosclerosis, vascular inflammation and Caspase-1/GSDMD expression. The pivotal role of SENP1 in regulating Caspase-1 and GSDMD expression and NLRP3 inflammasome responses were further confirmed in vitro . Mechanistically, SENP1 acts as a SUMO-specific protease to directly deSUMOylate IRF1, which in turn enhances IRF1 acetylation at lysine 78, thereby facilitating its recruitment to the CASP1 and GSDMD promoters and driving their transcriptional activation. A SUMOylation-deficient IRF1 mutant (IRF1-2KR) enhances CASP1 and GSDMD transcription in ECs and potentiates NLRP3 inflammasome responses, whereas an acetylation-deficient mutant derived from IRF1-2KR by an additional K78R mutation abrogates both effects. Endothelium-targeted delivery of IRF1-2KR accelerated atherosclerosis and vascular inflammation. Collectively, our findings establish the SENP1-IRF1 deSUMOylation-acetylation crosstalk as a previously unrecognized mechanism to promote endothelial NLRP3 inflammasome responses via transcriptional upregulation of Caspase-1 and GSDMD, and as a potential therapeutic target for atherosclerosis.

Heart failure with reduced ejection fraction (HFrEF) remains a major therapeutic challenge. B-cell lymphoma 2-associated transcription factor 1 (Bclaf1) is implicated in RNA splicing and cardiac disease, but its role in HFrEF pathogenesis is unknown. Here, we demonstrate that Bclaf1 expression is elevated in human HFrEF myocardium and in male murine pressure-overload models. Cardiac-specific Bclaf1 overexpression drives pathological hypertrophy and systolic dysfunction, whereas its genetic knockout or adeno-associated virus serotype 9 (AAV9)-mediated knockdown attenuates these phenotypes. Mechanistically, Bclaf1 interacts with the splicing factor serine/arginine-rich splicing factor 2 (Srsf2) to bind to heart and neural crest derivatives expressed 2 (Hand2) pre-mRNA and enhance its splicing efficiency, leading to increased mature Hand2 levels and maladaptive remodeling. Inhibition of either Bclaf1 or Hand2 rescues cardiac function and structure in experimental HFrEF. Our work defines a Bclaf1/Srsf2/Hand2 splicing axis as a critical driver of HFrEF and reveals a promising therapeutic target for heart failure.

Chronic kidney disease (CKD) significantly increases the risk of atrial fibrillation (AF). Although alterations in the gut microbiota have been linked to CKD progression, its exact involvement in CKD-associated AF remians unclear. We amis to investigate the role of gut microbiota in the development of CKD-associated AF, and to uncover potential mechanisms that could serve as effective targets for prevention and treatment. A rat model of CKD was induced by an adenine-enriched diet. 16S rRNA sequencing and fecal microbiota transplantation (FMT) were utilized to study the involvement of gut microbiota. AST-120, gut barrier protectants and mono-colonization experiments were performed to investigate potential mechanism. CKD rats exhibited gut microbiota dysbiosis and a significantly increased susceptibility to AF. FMT from CKD rats transferred this heightened AF susceptibility to healthy recipient rats, linked to the activation of the NLRP3 inflammasome. Mechanistically, gut dysbiosis in CKD patients leads to elevated IS levels, causing gut barrier dysfunction and increased circulating lipopolysaccharide (LPS). Elevated LPS activates atrial TLR4 receptors, triggering NLRP3 inflammasome activation, which contributes to AF pathogenesis. Treatment with the IS scavenger AST-120 or gut barrier protectants successfully prevented CKD-associated AF. Furthermore, supplementation with Lactobacillus gasseri reduced circulating IS levels and mitigated AF susceptibility in CKD rats. This study demonstrates that gut dysbiosis-driven elevation of IS and subsequent activation of the atrial NLRP3 inflammasome are key mechanisms in CKD-associated AF. Modulating the gut microbiota could provide a new therapeutic strategy for CKD-associated AF.

Endothelial cell (EC) dysfunction is a critical driver of chronic vascular inflammation and atherosclerosis. However, the molecular details of EC state dynamics during vascular disease progression remain ill-defined. Here, we used in-depth single-cell RNA sequencing to map transcriptional landscapes and molecular signatures of EC phenotypic plasticity during atherosclerosis in the mouse arota. This analysis identified a unique fibroblast-like EC population in atherosclerotic blood vessels, characterized by high expression of endothelial activation markers and extracellular matrix (ECM) remodeling, which increased with disease severity. Pseudotime trajectory analysis revealed that these fibroblast-like ECs represent terminal states of endothelial-mesenchymal transition (EndMT) during atherosclerosis. Further, the transcription factor C/EBPβ was identified as prominent driver of this phenotype transition as evidenced in vivo and in vitro. Mechanistically, inflammatory cytokines induce C/EBPβ, triggering TGF-β signaling and subsequent regulation of downstream genes via upregulation of TGF-β receptor type I (TGFBR1) through direct interaction with its promoter. Endothelial overexpression of C/EBPβ in vivo exacerbated atherosclerotic plaques, increased vascular inflammation, and elevated endothelial TGFBR1 levels. These findings highlight endothelial C/EBPβ as a novel regulator of TGF-β signaling and pathological fibroblast-like EC phenotypes during atherosclerosis, linking cytokine-driven inflammation with TGF-β-mediated endothelial dysfunction.

Atherosclerosis remains a major global health challenge with limited therapeutic options for plaque regression. Stem cell therapy and stem cell-derived exosomes represent promising novel strategies for treating this disease. Different types of stem cells demonstrate therapeutic effects by modulating lipid metabolism, reducing inflammation, and improving endothelial function. However, challenges such as poor targeting, low maintenance times, and immunogenicity limit their clinical application. Recent advances focus on engineering these cells and their exosomes to overcome these barriers. Strategies include genetic modification, surface functionalization for targeted delivery, and hybrid nanoparticle design. Engineered exosomes also serve as efficient drug carriers for precise therapy. While clinical trials show potential, further validation of long-term efficacy and safety is needed. Integrating bioengineering with regenerative technology offers a new approach for atherosclerosis treatment.

BACKGROUND: Pathological cardiac remodeling after myocardial infarction (MI) is a leading cause of heart failure and sudden death. The detailed mechanisms underlying the transition to heart failure after MI are not fully understood. Disruptions in the endoplasmic reticulum (ER)–mitochondria connectivity, along with mitochondrial dysfunction, are substantial contributors to this remodeling process. In this study, we aimed to explore the impact of mitochondrial tumor suppressor 1A (Mtus1A) on cardiac remodeling subsequent to MI and elucidate its regulatory role in ER-mitochondria interactions. METHODS: Single-nucleus RNA sequencing analysis was performed to delineate the expression patterns of mitochondrial tumor suppressor 1 (Mtus1) in human cardiomyocytes under ischemic stress. MI models were induced in mice by left coronary artery ligation and replicated in vitro using primary neonatal rat ventricular myocytes exposed to oxygen glucose deprivation. Cardiac-specific deletion of Mtus1 was achieved by crossing floxed Mtus1 mice with the Myh6-MerCreMer mice. The impact of Mtus1A, a mitochondrial isoform of Mtus1, on cardiac function and the molecular mechanisms were investigated in both in vivo and in vitro settings. Mitochondria-associated ER membranes (MAMs) coupling levels were evaluated by transmission electron microscopy and live-cell imaging. Protein interactions involving Mtus1A were explored through immunoprecipitation–mass spectrometry, coimmunoprecipitation, and proximity ligation assay. The roles of Mtus1A and Fbxo7 (F-box protein 7) were validated in a murine MI model using adeno-associated virus serotype 9 (AAV9). RESULTS: Bioinformatics analysis revealed a significant downregulation of Mtus1 expression in human cardiomyocytes under ischemic conditions, indicating its potential role in stress response. The predominant isoform in murine cardiomyocytes, Mtus1A, showed reduced expression in the left ventricle of mice after MI, which is consistent with the decreased levels of its orthologs in heart tissues from patients with MI. Cardiac-specific Mtus1-knockout mice exhibited worsened cardiac dysfunction after MI. Further studies demonstrated that Mtus1A partially localizes to MAMs, where it modulates MAMs coupling and preserves mitochondrial function. Mechanistically, Mtus1A functions as a scaffold protein that maintains the formation of inositol 1,4,5-trisphosphate receptor 1 (IP ₃ R1)–glucose-regulated protein 75 (Grp75)–voltage-dependent anion channel 1 (VDAC1) complex through its amino acid sequence 189-219. In addition, Mtus1A protein is stabilized by K6-linked ubiquitination through the E3 ubiquitin ligase Fbxo7. Mtus1A overexpression in mice mitigated MI-induced cardiac dysfunction and remodeling by maintaining MAMs integrity. CONCLUSIONS: Our study demonstrates that Mtus1A is crucial for modulating MI-induced cardiac remodeling by preserving ER-mitochondria communication and ameliorating mitochondrial function in cardiomyocytes. Mtus1A may serve as a potential therapeutic target for treating heart failure after MI.

Perinatal stem cells have prominent applications in cell therapy and regenerative medicine. Among them, human Wharton’s jelly mesenchymal stem/stromal cells (hWJMSCs) and human amniotic epithelial stem cells (hAESCs) have been widely used. However, the distinction in the therapeutic potential of hWJMSCs and hAESCs is poorly understood. In this study, we reported the phenotypic differences between these two distinct cell types and provided the first systematic comparison of their therapeutic potential in terms of immunomodulation, extracellular matrix (ECM) remodelling, angiogenesis and antioxidative stress using proteomics. The results revealed that the two cell types presented different protein expression profiles and were both promising candidates for cell therapy. Both types of cells demonstrated angiogenic and antifibrotic potential, whereas hAESCs presented superior immunological tolerance and antioxidant properties, which were supported by a series of relevant in vitro assays. Our study provides clues for the selection of appropriate cell types for diverse indications in cell therapy, which contributes to the advancement of their clinical translation and application.