Lgr5 ⁺ intestinal stem cells (ISCs) are crucial for the intestinal epithelium renewal and regeneration after injury. However, the mechanism underlying the interplay between Wnt and BMP signaling in this process is not fully understood. Here we report that Bcl11b, which is downregulated by BMP signaling, enhances Wnt signaling to maintain Lgr5 ⁺ ISCs and thus promotes the regeneration of the intestinal epithelium upon injury. Loss of Bcl11b function leads to a significant decrease of Lgr5 ⁺ ISCs in both intestinal crypts and cultured organoids. Mechanistically, BMP suppresses the expression of Bcl11b, which can positively regulate Wnt target genes by inhibiting the function of the Nucleosome Remodeling and Deacetylase (NuRD) complex and facilitating the β-catenin-TCF4 interaction. Bcl11b can also promote intestinal epithelium repair after injuries elicited by both irradiation and DSS-induced inflammation. Furthermore, Bcl11b deletion prevents proliferation and tumorigenesis of colorectal cancer cells. Together, our findings suggest that BMP suppresses Wnt signaling via Bcl11b regulation, thus balancing homeostasis and regeneration in the intestinal epithelium.

Coxsackievirus A10 (CV-A10) infection, a prominent cause of childhood hand-foot-and-mouth disease (HFMD), frequently manifests with the intriguing phenomenon of onychomadesis, characterized by nail shedding. However, the underlying mechanism is elusive. Here, we found that CV-A10 infection in mice could suppress Wnt/β-catenin signaling by restraining LDL receptor–related protein 6 (LRP6) phosphorylation and β-catenin accumulation and lead to onychomadesis. Mechanistically, CV-A10 mimics Dickkopf-related protein 1 (DKK1) to interact with Kringle-containing transmembrane protein 1 (KRM1), the CV-A10 cellular receptor. We further found that Wnt agonist (GSK3β inhibitor) CHIR99021 can restore nail stem cell differentiation and protect against nail shedding. These findings provide novel insights into the pathogenesis of CV-A10 and related viruses in onychomadesis and guide prognosis assessment and clinical treatment of the disease.

Background: Sepsis-related myocardial dysfunction significantly increases the mortality risk of sepsis. However, its underlying mechanism remains incompletely understood, and effective therapeutic strategies are still lacking. Transcriptomic profiling from septic patients showed endoplasmic reticulum stress (ERS) were the main pathways participating in the occurrence of sepsis myocardial dysfunction. Therefore, this study aimed to explore the protective effect of 4-phenylbutyric acid (4-PBA) on sepsis-induced myocardial injury and specify its molecular regulatory mechanism, to provide experimental basis for clinical intervention of septic myocardial dysfunction. Methods: In vivo and in vitro models of sepsis were used, and 4-PBA (5 mg/kg) was administered for intervention. Mitochondria-associated ER-membrane (MAM) formation, mitochondrial dynamics, mitochondrial function, glycolytic metabolism, and protein lactylation were systematically examined. Molecular docking and site-directed mutation were applied to verify the direct binding and catalytic sites of 4-PBA. Results: 4-PBA significantly alleviated sepsis-induced myocardial dysfunction. The mechanism was closely related to 4-PBA inhibiting MAM formation and improving the mitochondrial dynamic balance and mitochondrial function. 4-PBA inhibited MAM formation mainly via decreasing the lactate production and lactylation of Arpc1b-K308 by inhibiting the glycolysis limiting enzyme HK2, and 4-PBA inhibited HK2 activity by binding K621 and K624 catalytic sites. Conclusions: The results indicate that 4-PBA protects cardiac function following sepsis by recovering mitochondrial dynamics balance. This finding provides a novel therapeutic strategy and potential target for sepsis induced myocardial dysfunction.