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Abstract Background Pyroptosis of the renal tubular epithelial cells (RTECs) and interstitial inflammation are central pathological characteristics of acute kidney injury (AKI). Pyroptosis acts as a pro-inflammatory form of programmed cell death and is mainly dependent on activation of the NLRP3 inflammasome. Previous studies revealed that acetyl-CoA synthetase 2 (ACSS2) promotes inflammation during metabolic stress suggesting that ACSS2 might regulate pyroptosis and inflammatory responses of RTECs in AKI. Methods and results The expression of ACSS2 was found to be significantly increased in the renal epithelial cells of mice with lipopolysaccharide (LPS)-induced AKI. Pharmacological and genetic strategies demonstrated that ACSS2 regulated NLRP3-mediated caspase-1 activation and pyroptosis through the stimulation of the KLF5/NF-κB pathway in RTECs. The deletion of ACSS2 attenuated renal tubular pathological injury and inflammatory cell infiltration in an LPS-induced mouse model, and ACSS2-deficient mice displayed impaired NLRP3 activation-mediated pyroptosis and decreased IL-1β production in response to the LPS challenge. In HK-2 cells, ACSS2 deficiency suppressed NLRP3-mediated caspase-1 activation and pyroptosis through the downregulation of the KLF5/NF-κB pathway. The KLF5 inhibitor ML264 suppressed NF-κB activity and NLRP3-mediated caspase-1 activation, thus protecting HK-2 cells from LPS-induced pyroptosis. Conclusion Our results suggested that ACSS2 regulates activation of the NLRP3 inflammasome and pyroptosis by inducing the KLF5/NF-κB pathway in RTECs. These results identified ACSS2 as a potential therapeutic target in AKI. Graphical Abstract We found that the expression of ACSS2 was significantly increased in RTECs in septic AKI. ACSS2-deficient mice displayed resistance to renal damage in this model. ACSS2 regulated NLRP3-mediated caspase-1 activation and pyroptosis through the KLF5/NF-κB pathway in RTECs. Pharmacological inhibition of KLF5 suppressed NLRP3 activation and caspase-1 cleavage by downregulating of NF-κB. Our results suggest that ACSS2 is a pro-pathogenic mediator of cell pyroptosis of RTECs and renal inflammation in sepsis-induced AKI.

Evidence suggests that intracellular angiotensin II type 1 receptor (AT1) contributes to peritoneal fibrosis (PF) under high glucose (HG)-based dialysates. It is generally believed that AT2 antagonisticly affects AT1 function. The aim of this study was to explore whether AT2 activation is beneficial for attenuating human peritoneal mesothelial cell (HPMC) injury due to HG. We treated a HPMC line with HG to induce extracellular matrix (ECM) formation. AT2 was increased and blocked using CGP42112A and AT2 siRNA. Lipid deposition was detected, signaling molecules associated with lectin-like oxidized lipoprotein receptor-1 (LOX-1) and ECM proteins were evaluated by real-time PCR and western blot. The results showed that HG led to AT2 inhibition in HPMCs, inhibition of AT2 further aggravated the expression of ECM proteins, including α-smooth muscle actin, fibroblast specific protein-1 and collagen I, while AT2 decreased the expression of ECM proteins, even during HG stimulation. Interestingly, there was a parallel change in lipid accumulation and ECM formation when AT2 was increased or depressed. Moreover, AT2-mediated decreased ECM production was associated with reduced lipid accumulation in HPMCs and depended on the downregulation of LOX-1. Further analysis showed that HG increased oxidized low-density lipoprotein (ox-LDL) deposition in HPMCs concomitant with an enhanced expression of ECM components, whereas blocking LOX-1 reversed ox-LDL deposition even in the presence of HG. This effect was also accompanied by the remission of ECM accumulation. Our results suggested that AT2 prevented ECM formation in HG-stimulated HPMCs by ameliorating lipid via LOX‐1 suppression.

Staphylococcus haemolyticus (S. haemolyticus) is the second most commonly isolated coagulase-negative staphylococcus (CoNS) in patients with hospital-acquired infections. It can produce phenol-soluble modulin (PSM) toxins and form biofilms. Compared with the wealth of information on Staphylococcus aureus and Staphylococcus epidermidis, very little is known about S. haemolyticus. There is an urgent need to find an effective preparation to combat the harm caused by S. haemolyticus infection. Chinese herbs have been utilized to cure inflammation and infectious diseases and have a long history of anticancer function in China. Here, we modified fusaric acid characterized from the metabolites of Gibberella intermedia, an endophyte previously isolated from Polygonum capitatum. This study shows that fusaric acid analogs (qy17 and qy20) have strong antibacterial activity against S. haemolyticus. In addition, crystal violet analyses and scanning electron microscopy observations demonstrated that qy17 inhibited biofilm formation and disrupted mature biofilms of S. haemolyticus in a dose-dependent manner. Additionally, it reduced the number of live bacteria inside the biofilm. Furthermore, the antibiofilm function of qy17 was achieved by downregulating transcription factors (sigB), transpeptidase genes (srtA), and bacterial surface proteins (ebp, fbp) and upregulating biofilm-related genes and the density-sensing system (agrB). To further elucidate the bacteriostatic mechanism, transcriptomic analysis was carried out. The following antibacterial mechanisms were uncovered: (i) the inhibition of heat shock (clpB, groES, groL, grpE, dnaK, dnaJ)-, oxidative stress (aphC)- and biotin response (bioB)-related gene expression, which resulted in S. haemolyticus being unable to compensate for various stress conditions, thereby affecting bacterial growth; and (ii) a reduction in the expression of PSM-beta (PSMβ1, PSMβ2, PSMβ3) toxin- and Clp protease (clpP, clpX)-related genes. These findings could have major implications for the treatment of diseases caused by S. haemolyticus infections. Our research reveals for the first time that fusaric acid derivatives inhibit the expression of biofilm formation-related effector and virulence genes of S. haemolyticus. These findings provide new potential drug candidates for hospital-acquired infections caused by S. haemolyticus.

Abstract Background Bladder cancer (BCa) is one of the most common cancers in the urinary system among the world. Previous studies suggested that TMEM40 expression level was significantly associated with clinicopathological parameters including histological grade, clinical stage and pT status of bladder cancer. However, the molecular mechanism of TMEM40 in BCa remains poorly understood. Methods Real-time quantitative RT-PCR (qRT-PCR) and western blot (WB) were used to examine the expression levels of TMEM40 in BCa tissues, paired non-cancer tissues and cell lines. A series of experiments, including CCK-8, wound healing, flow cytometry, transwell and EdU assays were performed to assess the effects of TMEM40 on cell proliferation, cell cycle and apoptosis, migration and invasion. In addition, tumor growth was evaluated in vivo using a xenogenous subcutaneously implant model. All statistical analyses were executed by using the SPSS 20.0 software. All experimental data from three independent experiments were analyzed by Student’s t test and results were expressed as mean ± standard deviation. Results In this study, we identified the role of TMEM40 in the tumorigenesis of bladder cancer and found that it was upregulated in bladder cancer tissues and cell lines, compared with their normal counterparts. The results demonstrated that effective silence of TMEM40 expression suppressed cell proliferation, blocked G1-to-S cell cycle transition, and inhibited cell migration and invasion in human bladder 5637 and EJ cell lines. Consistently, in vivo data showed that TMEM40 silencing could dramatically decreased tumor growth. Further study revealed that TMEM40 knockdown resulted in accumulation of p53 and p21 protein and decrease of c-MYC and cyclin D1 protein. Conclusion These data suggest that TMEM40 represents a potential oncogene, which exert a crucial role in the proliferation and apoptosis via the p53 signaling pathway in BCa, thus probably serve as a novel candidate biomarker and a potential therapeutic target for patients with BCa.

Embryo implantation, a crucial step in human reproduction, is tightly controlled by estrogen and progesterone (P4) via estrogen receptor alpha and progesterone receptor (PGR), respectively. Here, we report that N6 -methyladenosine (m6 A), the most abundant mRNA modification in eukaryotes, plays an essential role in embryo implantation through the maintenance of P4 signaling. Conditional deletion of methyltransferase-like 3 (Mettl3), encoding the m6 A writer METTL3, in the female reproductive tract using a Cre mouse line with Pgr promoter (Pgr-Cre) resulted in complete implantation failure due to pre-implantation embryo loss and defective uterine receptivity. Moreover, the uterus of Mettl3 null mice failed to respond to artificial decidualization. We further found that Mettl3 deletion was accompanied by a marked decrease in PGR protein expression. Mechanistically, we found that Pgr mRNA is a direct target for METTL3- mediated m6 A modification. A luciferase assay revealed that the m6 A modification in the 5′ untranslated region (5′-UTR) of Pgr mRNA enhances PGR protein translation efficiency in a YTHDF1-dependent manner. Finally, we demonstrated that METTL3 is required for human endometrial stromal cell decidualization in vitro and that the METTL3-PGR axis is conserved between mice and humans. In summary, this study provides evidence that METTL3 is essential for normal P4 signaling during embryo implantation via m6 A-mediated translation control of Pgr mRNA. [ABSTRACT FROM AUTHOR]

Peritoneal dialysis (PD)-related peritoneal fibrosis (PF) is characterized by progressive extracellular matrix (ECM) accumulation in peritoneal mesothelial cells (PMCs) during long-term use of high glucose (HG)-based dialysates. Activation of the renin-angiotensin system (RAS) has been shown to be associated with PF. The aim of this study was to explore the underlying mechanism of the RAS in HG-induced PF. We treated C57BL/6 mice and a human PMC line with HG to induce a PF model and to stimulate ECM accumulation, respectively. RAS activity was blocked using valsartan or angiotensin II (ANGII) type 1 receptor siRNA. The major findings were as follows. First, mice in the HG group exhibited increased collagen deposition and expression of ECM proteins, including a-smooth muscle actin (a-SMA) and collagen type I in the peritoneum. Consistent with the in vivo data, HG upregulated a-SMA expression in human peritoneal mesothelial cells (HPMCs) in a time- and dose-dependent manner. Second, HG stimulation led to RAS activation in HPMCs, and inactivation of RAS decreased the expression of ECM proteins in vivo and in vitro, even during HG stimulation. Finally, RAS-mediated ECM production was associated with lipid accumulation in HPMCs and depended on the dysregulation of the low-density lipoprotein receptor (LDLr) pathway. HG-stimulated HPMCs showed increased coexpression of LDLr and α-SMA, whereas blockade of RAS activity reversed the effect. Furthermore, inhibition of LDLr signaling decreased α-SMA and collagen type I expression in HPMCs when treated with HG and ANG II. In conclusion, increased intracellular RAS activity impaired lipid homeostasis and induced ECM accumulation in HPMCs by disrupting the LDLr pathway, which contributed to PF. [ABSTRACT FROM AUTHOR]