Kuijieling decoction suppresses NLRP3-Mediated pyroptosis to alleviate inflammation and experimental colitis in vivo and in vitro.
Ulcerative colitis (UC) is an autoimmune disease. Although the mortality rate of UC is not very high, it has a considerable morbidity rate and an unsatisfactory cure rate. Without effective treatment, UC is likely to develop into colon cancer. Kuijieling (KJL) is an effective empirical formula to treat UC in the clinical setting, and it has been proven to have curative effects against UC.
In a previous study, we demonstrated that KJL could suppress NOD-like receptor protein 3 (NLRP3) to reduce inflammatory cytokines and alleviate UC. In this study, we investigated the mechanism of KJL in more detail, from the perspective of pyroptosis.
We established a dextran sulfate sodium-induced UC mouse model and RAW264.7 cells to measure different indicators with different experimental methods. The efficiency of KJL was evaluated by measuring the length and unit weight of mouse colons, and assessment of pathological injury was performed using HE staining. We detected different expression levels of NLRP3, apoptosis-associated speck-like protein containing a CARD (ASC), caspase-1, gasdermin-D C-terminal domain (GSDMD-C), gasdermin-D N-terminal domain (GSDMD-N), IL-1β, and IL-18 in colon tissues and cells using RT-qPCR and western blotting. Immunohistochemistry was used for tissues and immunofluorescence for cells to confirm protein expression. IL-1β and IL-18 were measured with enzyme-linked immunosorbent assay in serum, tissue, and cell culture supernatant. MiR-223 was detected using RT-qPCR.
After administration of KJL suspension, colon damage in KJL groups was milder than in model groups. ASC, caspase-1, IL-1β, and IL-18 mRNA levels in colon tissue were decreased to different degrees in the KJL groups. Protein expression of NLRP3, caspase-1, GSDMD-N, IL-1β, and IL-18 in vivo decreased significantly in the KJL groups. In addition, Mir-223 level decreased in colon tissue of the KJL groups. In vitro, NLRP3, ASC, caspase-1, GSDMD-N, IL-1β, and IL-18 levels decreased to varying degrees, at both mRNA and protein levels. Mir-223 was lower in the KJL groups than in the model group. Furthermore, KJL was shown to regulate the level of miR-223, which returned to normal after its expression was inhibited or promoted, and the levels of associated indicators also returned to normal after transfection.
KJL is able to inhibit pyroptosis to alleviate UC, but these suppression effects were not mediated through miR-223 regulation.
Jie F
，Xiao S
，Qiao Y
，You Y
，Feng Y
，Long Y
，Li S
，Wu Y
，Li Y
，Du Q
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Gegen Qinlian decoction ameliorates TNBS-induced ulcerative colitis by regulating Th2/Th1 and Tregs/Th17 cells balance, inhibiting NLRP3 inflammasome activation and reshaping gut microbiota.
Chinese herbal medicine Gegen Qinlian Decoction (GQD) has been clinically shown to be an effective treatment of ulcerative colitis (UC) in China. However, the underlying mechanism of GQD's anti-ulcerative colitis properties and its effect on gut microbiota still deserve further exploration.
This study observed the regulatory effects of GQD on Th2/Th1 and Tregs/Th17 cells balance, the NOD-like receptor family pyrin domain containing 3 (NLRP3) infammasome and gut microbiota in TNBS-induced UC in BALB/c mice.
61 main chemical compounds in the GQD were determined by UPLC-Q-TOF/MS. The UC BALB/c model was established by intrarectal administration of trinitrobenzene sulfonic acid (TNBS), and GQD was orally administered at low and high dosages of 2.96 and 11.83 g/kg/day, respectively. The anti-inflammatory effects of GQD for ulcerative colitis were evaluated by survival rate, body weight, disease activity index (DAI) score, colonic weight and index, spleen index, hematoxylin-eosin (HE) staining and histopathological scores. Flow cytometry was used to detect the percentage of CD4, Th1, Th2, Th17 and Tregs cells. The levels of Th1-/Th2-/Th17-/Tregs-related inflammatory cytokines and additional proinflammatory cytokines (IL-1β, IL-18) were detected by CBA, ELISA, and RT-PCR. The expressions of GATA3, T-bet, NLRP3, Caspase-1, IL-Iβ, Occludin and Zonula occludens-1 (ZO-1) on colon tissues were detected by Western blot and RT-PCR. Transcriptome sequencing was performed using colon tissue and 16S rRNA gene sequencing was performed on intestinal contents. Fecal microbiota transplantation (FMT) was employed to assess the contribution of intestinal microbiota and its correlation with CD4 T cells and the NLRP3 inflammasome.
GQD increased the survival rate of TNBS-induced UC in BALB/c mice, and significantly improved their body weight, DAI score, colonic weight and index, spleen index, and histological characteristics. The intestinal barrier dysfunction was repaired after GQD administration through promoting the expression of tight junction proteins (Occludin and ZO-1). GQD restored the balance of Th2/Th1 and Tregs/Th17 cells immune response of colitis mice, primarily inhibiting the increase in Th2/Th1 ratio and their transcription factor production (GATA3 and T-bet). Morever, GQD changed the secretion of Th1-/Th2-/Th17-/Tregs-related cytokines (IL-2, IL-12, IL-5, IL-13, IL-6, IL-10, and IL-17A) and reduced the expressions of IL-1β, IL-18. Transcriptome results suggested that GQD could also remodel the immune inflammatory response of colitis by inhibiting NOD-like receptor signaling pathway, and Western blot, immunohistochemistry and RT-PCR further revealed that GQD exerted anti-inflammatory effects by inhibiting the NLRP3 inflammasome, such as down-regulating the expression of NLRP3, Caspase-1 and IL-1β. More interestingly, GQD regulated gut microbiota dysbiosis, suppressed the overgrowth of conditional pathogenic gut bacteria like Helicobacter, Proteobacteria, and Mucispirillum, while the probiotic gut microbiota, such as Lactobacillus, Muribaculaceae, Ruminiclostridium_6, Akkermansia, and Ruminococcaceae_unclassified were increased. We further confirmed that GQD-treated gut microbiota was sufficient to relieve TNBS-induced colitis by FMT, involving the modulation of Th2/Th1 and Tregs/Th17 balance, inhibition of NLRP3 inflammasome activation, and enhancement of colonic barrier function.
GQD might alleviate TNBS-induced UC via regulating Th2/Th1 and Tregs/Th17 cells Balance, inhibiting NLRP3 inflammasome and reshaping gut microbiota, which may provide a novel strategy for patients with colitis.
Hu Y
，Tang J
，Xie Y
，Xu W
，Zhu W
，Xia L
，Fang J
，Yu D
，Liu J
，Zheng Z
，Zhou Q
，Shou Q
，Zhang W
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PSMB5 Alleviates Ulcerative Colitis by Inhibiting ROS-Dependent NLRP3 Inflammasome-Mediated Pyroptosis.
Ulcerative colitis (UC) is a chronic inflammatory disease. Intestinal mucosal injury is a significant factor in UC. Pyroptosis is a kind of programmed cell death induced by inflammatory caspases. Proteasome 20S subunit beta 5 (PSMB5) promotes cell viability. The purpose of this study was to determine the impact of PSMB5 on intestinal mucosal injury and to elucidate the underlying processes in dextran sulfate sodium- (DSS-) induced UC mice. Kunming (KM) mice received 3% DSS for 5 days to induce UC. We collected clinical symptoms, body weight, colon length, and histological changes. MDA (malondialdehyde) and SOD (superoxide dismutase) levels were determined using an ELISA assay. RT-PCR was used to assess the expression of IL-1β and IL-18. PSMB5 demonstrated a significant effect against UC by increasing body weight and colon length and decreasing DAI (disease activity index), colon macroscopic damage index (CMDI), histological injury scores, and reactive oxygen species (ROS), MDA, and SOD levels, thereby alleviating histopathological changes and inhibiting oxidative stress. HIEC-6 cells were exposed to lipopolysaccharide (LPS) condition with or without PSMB5, along with caspase-1 inhibitor (Z-VAD-FMK), NLRP3 inhibitor (MCC950), and ROS scavenger N-acetylcysteine (NAC). The viability of the cells, the release of lactate dehydrogenase (LDH), and intracellular ROS generation were determined using assay kits. Western blot analysis was used to determine the levels of NLRP3, ASC, cleaved caspase-1 (p20), pro-IL-1β, IL-1β, pro-IL-18, and IL-18. PSMB5 overexpression enhanced the inflammatory damage in LPS-treated HIEC-6 cells by activating the NLRP3 inflammasome and mediating pyroptosis, as demonstrated by increased LDH release and lower cell viability, as well as increased expression of NLRP3, ASC, cleaved caspase-1 (p20), IL-1, and IL-18. Meanwhile, NAC protected HIEC-6 cells from LPS-induced damage by reversing the activation of the NLRP3 inflammasome-mediated pyroptosis. In conclusion, PSMB5 may lower HIEC-6 cell susceptibility to LPS and ameliorate UC-induced HIEC-6 cell damage by decreasing ROS generation and hence inhibiting NLRP3-mediated pyroptosis.
Han L
，Hao Y
，Wu X
，Hu D
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