Lipopolysaccharide upregulates miR-132/212 in Hirschsprung-associated enterocolitis, facilitating pyroptosis by activating NLRP3 inflammasome via targeting Sirtuin 1 (SIRT1)

Abstract

Hirschsprung disease (HSCR) is a congenital disorder attributed to the failure of the neural crest derivatives migrating and/or differentiating along the hindgut. The most frequent complication in Hirschsprung disease patients is Hirschsprung-associated enterocolitis (HAEC). However, its pathogenesis has not been fully understood. This study investigated miRNAs influenced by Lipopolysaccharide (LPS) in postoperative HAEC patients, their effect on enterocolitis and the underlying mechanism. MiR-132 and miR-212 were up-regulated in HAEC dilated tissues and LPS-treated mice enteritis samples. LPS-stimulated HT29 cells showed a high expression of miR-132 and miR-212. QRT-PCR analysis, western blotting, luciferase reporter assay, and flow cytometric analysis were carried out in vitro, showing that miR-132 and miR-212 could directly inhibit Sirtuin 1 (SIRT1) expression. Consequently, SIRT1 deficiency in LPS-stimulated HT29 cell line and LPS-treated mice activated NLRP3 inflammasome and Caspase-1-mediated pyroptosis. Furthermore, the above inflammation activation was reversed by miR-132/212 inhibitor or SIRT1 overexpression plasmid transfection. In conclusion, LPS upregulated miR-132 and miR-212 expression in HAEC, suppressing SIRT1 and facilitating NLRP3 inflammasome activation, which induced pyroptosis. Our findings illustrated the role of LPS/miR-132/-212/SIRT1/NLRP3 regulatory network in the occurrence and progression of HAEC and proposed a new molecular pathway for LPS-mediated cell pyroptosis.

BRD4 Inhibition by JQ1 Protects Against LPS-Induced Cardiac Dysfunction by Inhibiting SIRT1-Dependent Activation of NLRP3 Inflammasomes

“…In this study, we con rmed that NLRP3 in ammasome activation plays a vital role in the pathogenesis of LPS-induced cardiac dysfunction, which is consistent with previous studies [3,20,21,23]. This study is the rst to demonstrate a protective effect of THE BRD4 inhibitor JQ1 on LPS-induced cardiac dysfunction.This study found that JQ1 signi cantly reduces cellular in ammation by inhibiting NLRP3 in ammasome activation in vivo and in vitro.…”

“…Sepsis is a complex multi-organ dysfunction syndrome Cardiac contraction and diastolic dysfunction are often seen in patients with severe sepsis [18].It should be noted that cardiovascular disease remains a signi cant cause of morbidity and mortality worldwide [6].Lipopolysaccharide(LPS), a signi cant component of the outer membrane of Gram-negative bacteria that can trigger pathologies such as systemic in ammatory response syndrome (SIRS) and septic shock, has been widely used in the establishment of models of cardiac dysfunction in sepsis [20].Therefore, it is crucial to explore the mechanisms of LPS-induced cardiac dysfunction. NOD-like receptor protein 3 (NLRP3) is an intracellular protein complex that regulates the body's in ammatory response [14].At the onset of in ammation, The NLRP3 is rapidly triggered for activation, activated NLRP3 binds to apoptosis-associated speck-like protein (ASC), then recruits caspase 1 to assemble into an in ammasome complex prompting the release of proin ammatory cytokines IL-1b and IL-18 and upregulating GSDMD, leading to pyroptosis [15,17,34].Previous studies have shown that NLRP3 in ammasome activation in cardiac broblasts during sepsis-induced maturation and release the in ammatory factors such as IL-1β, inhibiting activation of the NLRP3 in ammasome in myocardial broblasts, can alleviate LPS-induced myocardial dysfunction and improve survival in mice with peritonitis sepsis [40].…”

Artemisinin analog SM934 alleviates epithelial barrier dysfunction via inhibiting apoptosis and caspase-1-mediated pyroptosis in experimental colitis

“…Accumulating evidence indicates that microbiota-driven activation of inflammatory responses and pathological immune activation to further progressive tissue damage through the release of pro-inflammatory mediators from dying IECs is commonly associated with inflammatory pyroptosis ( Wang et al, 2021 ). It is well known that pyroptosis is defined as caspase-1-dependent programmed cell death that is activated by the NOD-, LRR-, and pyrin domain-containing 3 (NLRP3) inflammasomes, which is a cytosolic protein complex composed of NLRP3, the adapter apoptosis-associated speck-like protein (ASC) and procaspase-1 ( Li et al, 2020 ). In addition, activation of NLRP3 facilitates pro-caspase-1 into cleaved caspase-1 formation.…”

Different Fecal Microbiota in Hirschsprung's Patients With and Without Associated Enterocolitis

“…However, why some Hirschsprung patients develop Hirschsprung-associated enterocolitis but others do not remain unclear. Altered immune system and gut homeostasis maintenance mechanisms due to genetic susceptibility (Bachetti et al, 2021 ) or defects in epithelial cell barrier components (Gosain, 2016 ; Nakamura et al, 2018 ; Li et al, 2020 ) in Hirschsprung patients developing Hirschsprung-associated enterocolitis have been reported. A role of a specific gut microbiota composition in Hirschsprung-associated enterocolitis patients compared with non-enterocolitis ones, leading to altered barrier function and gut immune system development, is therefore likely in Hirschsprung-associated enterocolitis.…”