Novel MAGL Inhibitors Alleviate LPS-Induced Acute Kidney Injury by Inhibiting NLRP3 Inflammatory Vesicles, Modulating Intestinal Flora, Repairing the Intestinal Barrier, and Interfering with Serum Metabolism.

Acute kidney injury (AKI) is a complication of a wide range of serious illnesses for which there is still no better therapeutic agent. We demonstrated that M-18C has a favorable inhibitory effect on monoacylglycerol lipase (MAGL), and several studies have demonstrated that nerve inflammation could be effectively alleviated by inhibiting MAGL, suggesting that M-18C has good anti-inflammatory activity. In this study, we investigated the effect of M-18C on LPS-induced acute kidney injury (AKI), both in vivo and in vitro, by using liquid chromatography-mass spectrometry (LC-MS), 16S rRNA gene sequencing, Western blot, and immunohistochemistry. The results showed that both in vivo and in vitro M-18C reduced the release of TNF-α and IL-1ß by inhibiting the expression of NOD-like receptor thermal protein domain-associated protein 3 (NLRP3) and apoptosis-associated speck-like protein containing a CARD (ASC) protein; in addition, M-18C was able to intervene in LPS-induced AKI by ameliorating renal pathological injury, repairing the intestinal barrier, and regulating gut bacterial flora and serum metabolism. In conclusion, this study suggests that M-18C has the potential to be a new drug for the treatment of AKI.

[Therapeutic effect and mechanism of Mailuo Shutong Pills on posterior limb swelling caused by femur fracture in rats based on intestinal flora and intestinal metabolism].

This study aimed to investigate the protective effect and underlying mechanism of Mailuo Shutong Pills(MLST) on posterior limb swelling caused by femur fracture in rats. The rats were randomly divided into a sham operation group, a model group, a low-dose MLST group(1.8 g·kg~(-1)·d~(-1)), a high-dose MLST group(3.6 g·kg~(-1)·d~(-1)), and a positive drug group(60 mg·kg~(-1)·d~(-1) Maizhiling Tablets). The femur in the sham operation group was exposed and the wound was sutured, while the other four groups underwent mechanical damage to cause femur fracture. The rats were treated with corresponding drugs by gavage 7 days before modeling and 5 days after modeling, while those in the sham operation group and the model group were given an equivalent dose of distilled water by gavage. Hematoxylin-eosin(HE) staining was used to detect the pathological injury of the posterior limb muscle tissues in rats, and the degree of hind limb swelling was measured. The enzyme-linked immunosorbent assay(ELISA) kit was used to detect the expression levels of interleukin-6(IL-6), interleukin-1ß(IL-1ß), and tumor necrosis factor-α(TNF-α) in the serum of rats in each group. The activity of superoxide dismutase(SOD), malondialdehyde(MDA), catalase(CAT), and glutathione peroxidase(GSH-Px) in rat serum was also measured. Western blot was used to detect the protein expression levels of heme oxygenase 1(HO-1), NAD(P)H quinone oxidoreductase 1(NQO1), and nuclear transcription factor E2-related factor 2(Nrf2) in rat posterior limb muscle tissues. The changes in the intestinal flora and intestinal metabolites in rats were detected by 16S rDNA sequencing and ultra-performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS), respectively, to explore the underlying mechanism of MLST in treating posterior limb swelling caused by femur fracture in rats. Compared with the model group, MLST significantly improved the degree of posterior limb swelling in rats, reduced the levels of serum inflammatory factors, and alleviated oxidative stress injury. The HE staining results showed that the inflammatory infiltration in the posterior limb muscle tissues of rats in the MLST groups was significantly improved. Western blot results showed that MLST significantly increased the protein expression of HO-1, NQO1, and Nrf2 in rat posterior limb muscle tissues compared with the model group. The 16S rDNA sequencing results showed that MLST improved the disorder of intestinal flora in rats after femur fracture. The UPLC-MS/MS results showed that MLST significantly affected the bile acid biosynthesis and metabolism pathway in the intestine after femur fracture, and the Spearman analysis confirmed that the metabolite deoxycholic acid involved in bile acid biosynthesis was positively correlated with the abundance of Turicibacter. The metabolite cholic acid was positively correlated with the abundance of Papilibacter, Staphylococcus, and Intestinimonas. The metabolite lithocholic acid was positively correlated with Papilibacter and Intestinimonas. The above results indicated that MLST could protect against the posterior limb swelling caused by femur fracture in rats. This protective effect may be achieved by improving the pathological injury of the posterior limb muscle, reducing the expression levels of inflammatory and oxidative stress-related factors in serum, reducing the oxidative injury of the posterior limb muscle, improving intestinal flora, and balancing the biosynthesis of bile acids in the intestine.

The Tryptophan Metabolite Indole-3-Carboxaldehyde Alleviates Mice with DSS-Induced Ulcerative Colitis by Balancing Amino Acid Metabolism, Inhibiting Intestinal Inflammation, and Improving Intestinal Barrier Function.

Ulcerative colitis (UC) has attracted much attention for its negative influence on quality of life and increased risk of colorectal cancer. Chemical and biological drugs are currently the usual treatment for UC. These drugs always induce severe side effects, or patients might become resistant to these therapies. Therefore, new therapeutic options for UC are urgently needed. In this study, we discovered the inhibitory activity of the intestinal tryptophan metabolite indole-3-carboxaldehyde (3-IAld) in dextran sulfate sodium salt (DSS)-induced UC mice by targeting the TLR4/NF-κB/p38 signaling pathway. This compound effectively protected against colon length shortening and damage induced by DSS in the colon, notably reducing the severity of inflammation. The production of inflammatory factors of TNF-α, IL-6, and IL-1ß was significantly attenuated when treating with 3-IAld in vivo and vitro. This might be attributed to inhibition of the TLR4/NF-kB/p38 signaling pathway. Moreover, 3-IAld could up-regulate the expression of ZO-1 and Occludin in vivo and vitro. Meanwhile, liquid chromatography mass spectrometry (LC-MS) results showed that 3-IAld could balance the aspartate and glutamate metabolism and the lysine degradation metabolism in the serum of DSS-induced colitis mice. In conclusion, 3-IAld ameliorated the intestinal barrier dysfunction and inflammatory response in DSS-induced UC mice, balanced amino acid metabolism, and inhibited the activation of the TLR4/NF-kB/p38 signaling pathway, thereby protecting mice with colitis.