Super-enhancers play prominent roles in driving robust pathological gene expression, but they are hidden in human genome at noncoding regions, making them difficult to explore. Leukemia inhibitory factor (LIF) is a multifunctional cytokine crucially involved in acute respiratory distress syndrome (ARDS) and lung cancer progression. However, the mechanisms governing LIF regulation in disease contexts remain largely unexplored. In this study, we observed elevated levels of LIF in the bronchoalveolar lavage fluid (BALF) of patients with sepsis-related ARDS compared to those with nonsepsis-related ARDS. Furthermore, both basal and LPS-induced LIF expression were under the control of super-enhancers. Through analysis of H3K27Ac ChIP-seq data, we pinpointed three potential super-enhancers (LIF-SE1, LIF-SE2, and LIF-SE3) located proximal to the LIF gene in cells. Notably, genetic deletion of any of these three super-enhancers using CRISPR-Cas9 technology led to a significant reduction in LIF expression. Moreover, in cells lacking these super-enhancers, both cell growth and invasion capabilities were substantially impaired. Our findings highlight the critical role of three specific super-enhancers in regulating LIF expression and offer new insights into the transcriptional regulation of LIF in ARDS and lung cancer.

Ferroptosis, an iron-dependent form of programmed cell death, is a promising strategy for cancer treatment. Bromodomain-containing protein 4 (BRD4) is an epigenetic reader and a promising target for cancer therapeutics. However, the role of BRD4 in ferroptosis is controversial and the value of the interaction between BRD4 inhibitors and ferroptosis inducers remains to be explored. Here, we found that BRD4 inhibition greatly enhanced erastin-induced ferroptosis in different types of cells, including HEK293T, HeLa, HepG2, RKO, and PC3 cell lines. Knocking down BRD4 in HEK293T and HeLa cells also promoted erastin-induced cell death. BRD4 inhibition by JQ-1 and I-BET-762 or BRD4 knockdown resulted in substantial accumulation of reactive oxygen species (ROS) in both HEK293T and HeLa cells. The effect of BRD4 inhibition on ferroptosis-associated genes varied in different cells. After using BRD4 inhibitors, the expression of FTH1, Nrf2, and GPX4 increased in HEK293T cells, while the levels of VDAC2, VDAC3, and FSP1 decreased. In HeLa cells, the expression of FTH1, VDAC2, VDAC3, Nrf2, GPX4, and FSP1 was reduced upon treatment with JQ-1 and I-BET-762. Consistently, the level of FSP1 was greatly reduced in HEK293T and HeLa cells with stable BRD4 knockdown compared to control cells. Furthermore, ChIP-sequencing data showed that BRD4 bound to the promoter of FSP1, but the BRD4 binding was greatly reduced upon JQ-1 treatment. Our results suggest that ROS accumulation and FSP1 downregulation are common mechanisms underlying increased ferroptosis with BRD4 inhibitors. Thus, BRD4 inhibitors might be more effective in combination with ferroptosis inducers, especially in FSP1-dependent cancer cells.

BackgroundLipopolysaccharide (LPS) is an endotoxin that causes inflammation, and the content of LPS increases gradually during the process of aging. Whether the response of the colon to LPS stimulation will increase with age is yet unknown.ObjectiveThe study investigated the effects of LPS stimulation on the colon of adult and aging rats.Method43 healthy male SD rats were divided into 4 different groups: adult group and LPS-stimulated adult group at the age of 4 months, and aging group and LPS-stimulated aging group at the age of 22 months. Rats were stimulated by intraperitoneal injection of LPS (1mg/kg) for 24 h. The morphological changes of the colon were observed, and intestinal inflammatory response, tight junction proteins, apoptosis, and proliferation in intestinal epithelial cells were detected.ResultsA series of morphology changes occurred in the colon of adult rats after LPS stimulation, the higher inflammatory response (TLR4, NF-κB, and IL-1β), changes in the protein levels of tight junctions (ZO-1, Claudin1, and Claudin2), and increased apoptosis (Bax, Bcl2) and proliferation (PCNA) of intestinal epithelial cells. The above changes were also found in aging rats. LPS stimulation further promotes the above changes to some extent in the colon of aging rats.ConclusionA series of colon changes in rats was significantly damaged during LPS stimulation and aging, and these changes were further aggravated to some extent in LPS-stimulated aging rats.

Inflammatory cytokines including TNF-α and IL-1β impair intestinal barrier function in aging by disrupting intestinal tight junction integrity. Icariin (ICA) has a variety of pharmacological effects. Indeed, ICA produces anti-inflammatory, anti-oxidative stress, and inhibitory effects on microRNA (miRNA) expression. This study was to explore whether ICA could alleviate inflammation-associated intestinal barrier function impairment in aging and its underlying mechanism. Of particular interest, network pharmacology prediction indicated the potential therapeutic impacts of ICA for the treatment of colitis. Then, rats were used to study whether ICA has a protective effect on the reduction of tight junctions caused by inflammatory cytokines. Next, Caco-2 cell monolayers were used to explore the mechanism by which ICA alleviates the down-regulation of tight junctions. Network pharmacology prediction revealed that ICA alleviated colitis via suppressing oxidative stress. After ICA intervention, expressions of inflammatory cytokines were reduced, but tight junctions, antioxidant enzymes in aging rats were up-regulated. ICA reversed the TNF-α-induced decrease in abundance of Occludin protein in Caco-2 cell monolayers. Meanwhile, ICA alleviated the increase in permeability and expression of miR-122a. However, the protective effect of ICA was markedly attenuated after transfection with miR-122a mimics. In conclusion, ICA reduced the expressions of Occludin, Claudin1, and Claudin5 in colon, which were related to the reduction of TNF-α and IL-1β and alleviation of colonic in vivore. And ICA attenuated TNF-α-induced Occludin disruption and epithelial barrier impairment by decreasing miR-122a expression in Caco-2 cell monolayers.

潘氏细胞是重要的微环境信号分子提供者,可为小肠干细胞(intestinal stem cells,ISCs)提供Wnt、Notch、EGF、mTORC1等相关信号因子,维持干细胞的增殖和分化平衡.对潘氏细胞提供ISCs微环境信号因子,以及潘氏细胞相关信号因子变化导致的小肠上皮稳态失调进行概述,旨在为潘氏细胞和ISCs相互作用的研究提供思考,为相关小肠上皮稳态失调提供新的治疗思路.