Lactiplantibacillus plantarum ATCC8014 Alleviates Postmenopausal Hypercholesterolemia in Mice by Remodeling Intestinal Microbiota to Increase Secondary Bile Acid Excretion.

Hypercholesterolemia poses a significant cardiovascular risk, particularly in postmenopausal women. The anti-hypercholesterolemic properties of Lactiplantibacillus plantarum ATCC8014 (LP) are well recognized; however, its improving symptoms on postmenopausal hypercholesterolemia and the possible mechanisms have yet to be elucidated. Here, we utilized female ApoE-deficient (ApoE-/-) mice undergoing bilateral ovariectomy, fed a high-fat diet, and administered 109 colony-forming units (CFU) of LP for 13 consecutive weeks. LP intervention reduces total cholesterol (TC) and triglyceride (TG) accumulation in the serum and liver and accelerates their fecal excretion, which is mainly accomplished by increasing the excretion of fecal secondary bile acids (BAs), thereby facilitating cholesterol conversion. Correlation analysis revealed that lithocholic acid (LCA) is an important regulator of postmenopausal lipid abnormalities. LP can reduce LCA accumulation in the liver and serum while enhancing its fecal excretion, accomplished by elevating the relative abundances of Allobaculum and Olsenella in the ileum. Our findings demonstrate that postmenopausal lipid dysfunction is accompanied by abnormalities in BA metabolism and dysbiosis of the intestinal microbiota. LP holds therapeutic potential for postmenopausal hypercholesterolemia. Its effectiveness in ameliorating lipid dysregulation is primarily achieved through reshaping the diversity and abundance of the intestinal microbiota to correct BA abnormalities.

BRD4 promotes LPS-induced endothelial cells senescence via activating and cooperating STING-IRF3 pathway.

Endothelial cells (ECs) senescence is closely associated with the initiation and development of multiple age-related cardiovascular diseases. It is necessary to explore the underlying molecular mechanisms of ECs senescence, which is not only the basis to decipher cellular senescence, but also a novel therapeutic target for the endothelial senescence-related diseases. BRD4, a key epigenetic regulator, is universally related to gene expression regulation and has been reported to accelerate cell senescence. Besides, emerging evidence has suggested that the stimulator of interferon genes protein (STING) can regulate inflammatory and senescence-related diseases. However, whether STING pathway activation is regulated by BRD4 in the context of ECs senescence remains largely unclear. Here, we observed that elevated BRD4 and activated STING-IRF3 signaling pathway during ECs senescence and further confirmed that BRD4 could abolish STING activation. We demonstrated that BRD4 could inhibit E3 ubiquitin ligase HRD1-mediated ubiquitination degradation of STING via inhibiting HRD1 transcription. In addition to the direct regulatory effect of BRD4 on STING activation, we have confirmed that BRD4 cooperates with IRF3 and P65 to promote SASP gene expression, thereby accelerating ECs senescence. Here, we proposed a novel mechanism underlying BRD4' key dual role in activating the STING pathway during ECs senescence.

Non-canonical STING-PERK pathway dependent epigenetic regulation of vascular endothelial dysfunction via integrating IRF3 and NF-κB in inflammatory response.

Inflammation-driven endothelial dysfunction is the major initiating factor in atherosclerosis, while the underlying mechanism remains elusive. Here, we report that the non-canonical stimulator of interferon genes (STING)-PKR-like ER kinase (PERK) pathway was significantly activated in both human and mice atherosclerotic arteries. Typically, STING activation leads to the activation of interferon regulatory factor 3 (IRF3) and nuclear factor-kappa B (NF-κB)/p65, thereby facilitating IFN signals and inflammation. In contrast, our study reveals the activated non-canonical STING-PERK pathway increases scaffold protein bromodomain protein 4 (BRD4) expression, which encourages the formation of super-enhancers on the proximal promoter regions of the proinflammatory cytokines, thereby enabling the transactivation of these cytokines by integrating activated IRF3 and NF-κB via a condensation process. Endothelium-specific STING and BRD4 deficiency significantly decreased the plaque area and inflammation. Mechanistically, this pathway is triggered by leaked mitochondrial DNA (mtDNA) via mitochondrial permeability transition pore (mPTP), formed by voltage-dependent anion channel 1 (VDAC1) oligomer interaction with oxidized mtDNA upon cholesterol oxidation stimulation. Especially, compared to macrophages, endothelial STING activation plays a more pronounced role in atherosclerosis. We propose a non-canonical STING-PERK pathway-dependent epigenetic paradigm in atherosclerosis that integrates IRF3, NF-κB and BRD4 in inflammatory responses, which provides emerging therapeutic modalities for vascular endothelial dysfunction.

Autophagy enhanced by curcumin ameliorates inflammation in atherogenesis via the TFEB-P300-BRD4 axis.

Disturbance of macrophage-associated lipid metabolism plays a key role in atherosclerosis. Crosstalk between autophagy deficiency and inflammation response in foam cells (FCs) through epigenetic regulation is still poorly understood. Here, we demonstrate that in macrophages, oxidized low-density lipoprotein (ox-LDL) leads to abnormal crosstalk between autophagy and inflammation, thereby causing aberrant lipid metabolism mediated through a dysfunctional transcription factor EB (TFEB)-P300-bromodomain-containing protein 4 (BRD4) axis. ox-LDL led to macrophage autophagy deficiency along with TFEB cytoplasmic accumulation and increased reactive oxygen species generation. This activated P300 promoted BRD4 binding on the promoter regions of inflammatory genes, consequently contributing to inflammation with atherogenesis. Particularly, ox-LDL activated BRD4-dependent super-enhancer associated with liquid-liquid phase separation (LLPS) on the regulatory regions of inflammatory genes. Curcumin (Cur) prominently restored FCs autophagy by promoting TFEB nuclear translocation, optimizing lipid catabolism, and reducing inflammation. The consequences of P300 and BRD4 on super-enhancer formation and inflammatory response in FCs could be prevented by Cur. Furthermore, the anti-atherogenesis effect of Cur was inhibited by macrophage-specific Brd4 overexpression or Tfeb knock-out in Apoe knock-out mice via bone marrow transplantation. The findings identify a novel TFEB-P300-BRD4 axis and establish a new epigenetic paradigm by which Cur regulates autophagy, inhibits inflammation, and decreases lipid content.

Melatonin antagonizes ovarian aging via YTHDF2-MAPK-NF-κB pathway.

Cellular senescence is closely associated with age-related diseases. Ovarian aging, a special type of organ senescence, is the pathophysiological foundation of the diseases of the reproductive system. It is characterized by the loss of integrity of the surface epithelium and a gradual decrease in the number of human ovarian surface epithelial cells (HOSEpiCs). To contribute to the research on delaying ovarian aging, we aimed to investigate the novel epigenetic mechanism of melatonin in protecting HOSEpiCs. We discovered that melatonin has antagonistic effects against the oncogene-induced senescence (OIS) of HOSEpiCs. Mechanistically, the oncogene Ras decreased the expression of YTHDF2, which is the reader of RNA-m6A, by stimulating the generation of reactive oxygen species (ROS). Moreover, we found that the suppression of YTHDF2 increased the expression of MAP2K4 and MAP4K4 by enhancing the stability of the transcription of their mRNAs, thereby upregulating the expression of the senescence-associated secretory phenotype (SASP) through the activation of the MAP2K4 and MAP4K4-dependent nuclear factor-κB (NF-κB) signaling pathways. We further determined that melatonin has antagonistic effects against the OIS of HOSEpiCs by inhibiting the ROS-YTHDF2-MAPK-NF-κB pathway. These findings provide key insights into the potential avenues for preventing and treating ovarian aging.

BRD4 contributes to LPS-induced macrophage senescence and promotes progression of atherosclerosis-associated lipid uptake.

Aging is closely associated with atherosclerosis. Macrophages accumulate in atherosclerotic lesions contributing to the development and progression of atherosclerosis. Although atherosclerotic lesions are known to contain senescent cells, the mechanism underlying the formation of senescent macrophages during atherosclerosis is still unclear. In this study, macrophages with different origins were collected, including THP-1 macrophages, telomerase reverse transcriptase knock out (Tert-/-) mouse peritoneal macrophages, and human peripheral blood mononuclear cells (PBMCs). We found Lipopolysaccharide (LPS) could induce the formation of senescent macrophages, which was typified by the morphological changes, senescence-associated secretory phenotype (SASP) secretory, and persistent DNA damage response. Mechanistically, bromodomain-containing protein 4 (BRD4), a chromosomal binding protein related to gene expression, was found to play a key role in the pathological process, which could offer new therapeutic perspectives. Inhibition of BRD4 by siBRD4 or inhibitors such as JQ-1 or I-BET762 prevented the aging of macrophages and lipid accumulation in the LPS-induced senescent macrophages by decreasing expression of SASP in autocrine and paracrine senescence. These findings have significant implications for the understanding of the pathobiology of age-associated diseases and may guide future studies on targeted clinical drug therapy.