The m6A methyltransferase METTL3 affects cell proliferation and migration by regulating YAP expression in Hirschsprung disease.

BACKGROUND: METTL3, an mRNA m6A methyltransferase, has been implicated in various steps of mRNA metabolism, such as stabilization, splicing, nuclear transportation, translation, and degradation. However, whether METTL3 dysregulation is involved in Hirschsprung disease (HSCR) development remains unclear. In this study, we preliminarily elucidated the role of METTL3 in HSCR and sought to identify the associated molecular mechanism. METHODS: The gene expression levels of YAP and several methyltransferases, demethylases, and effectors were evaluated by RT-qPCR. Protein levels were evaluated by western blot and immunohistochemistry. Cell proliferation and migration were detected by CCK-8 and Transwell assays, respectively. The overall levels of m6A modification were determined by colorimetry. RESULTS: We found that m6A levels were reduced in the stenotic intestinal tissue of patients with HSCR. When METTL3 was knocked down in SH-SY5Y and HEK-293T cells, the proliferative and migratory abilities of the cells were inhibited, m6A modification levels were reduced, and YAP expression was increased. Importantly, YAP and METTL3 expression displayed a negative correlation in both cell lines as well as in HSCR tissue. CONCLUSIONS: Our results provide evidence for an interaction between METTL3 and YAP in HSCR, and further suggest that METTL3 is involved in the pathogenesis of HSCR by regulating neural crest cell proliferation and migration upstream of YAP.

Case report: A case of epidermolysis bullosa complicated with pyloric atresia and a literature review.

Objective: This article aims to explore the diagnosis, molecular characteristics, treatment, and prognosis of epidermolysis bullosa with pyloric atresia (EB-PA). Methods: The clinical manifestations, diagnosis and treatment, and genetic characteristics of a patient with EB-PA admitted to our hospital were analysed. The disease subtypes, concomitant abnormalities, molecular characteristics, and prognosis of patients with EB-PA were summarized by searching the EB-PA-related literature since 2011. Results: We present a very low birth weight female infant with skin blisters and pyloric obstruction. Exome sequencing revealed heterozygous mutations in the ITGB4 gene: c.794dupC (p. S265fs*5) and c.2962G > A (p.A988T). This infant was diagnosed with EB-PA. Coverage of the wounds and Penicillin were used to prevent infection, but the patient eventually developed severe sepsis. A literature review was carried out including 49 cases of EB-PA; among these cases, 34 were preterm infants, weighing between 930 and 3,640 g. Of these EB-PA patients, 28 had accompanying malformations, including urinary system malformations and aplasia cutis congenita (ACC). Thirty-two patients identified the subtype of EB-PA, of whom 25 were diagnosed with junctional epidermolysis bullosa (JEB), 6 with epidermolysis bullosa simplex (EBS), and 1 with dystrophic epidermolysis bullosa (DEB). Genetic testing was conducted on 23 patients, of whom 15 carried Integrin Beta-4 (ITGB4) gene mutations and one JEB patient carried an Integrin Alpha-6 (ITGA6) gene mutation; 4 of the 5 EBS patients had Plectin (PLEC) gene mutations, and the other had an ITGB4 mutation. ITGB4 mutation cases involved 29 mutation sites, primarily concentrated in the region encoding the integrin beta subunit; PLEC mutation cases involved 7 mutation sites. Among all cases, 43 underwent pyloric atresia surgery, of whom 24 died postoperatively, and 6 without surgery therapy died within a short period. Conclusion: EB-PA is a rare genetic disorder characterized by increased skin fragility and PA involving mutations in the ITGB4, PLEC, or ITGA6 genes. EB-PA has a high incidence of complications and mortality, surgery and supportive therapy are currently the most common treatment options.