Differentiation of intestinal stem cells toward goblet cells under systemic iron overload stress are associated with inhibition of Notch signaling pathway and ferroptosis.

Iron overload can lead to oxidative stress and intestinal damage and happens frequently during blood transfusions and iron supplementation. However, how iron overload influences intestinal mucosa remains unknown. Here, the aim of current study was to investigate the effects of iron overload on the proliferation and differentiation of intestinal stem cells (ISCs). An iron overload mouse model was established by intraperitoneal injection of 120 mg/kg body weight iron dextran once a fortnight for a duration of 12 weeks, and an iron overload enteroid model was produced by treatment with 3 mM or 10 mM of ferric ammonium citrate for 24 h. We found that iron overload caused damage to intestinal morphology with a 64 % reduction in villus height/crypt depth ratio, and microvilli injury in the duodenum. Iron overload mediated epithelial function by inhibiting the expression of nutrient transporters and enhancing the expression of secretory factors in the duodenum. Meanwhile, iron overload inhibited the proliferation of ISCs and regulated their differentiation into secretory mature cells, such as goblet cells, through inhibiting Notch signaling pathway both in mice and enteroid. Furthermore, iron overload caused oxidative stress and ferroptosis in intestinal epithelial cells. In addition, ferroptosis could also inhibit Notch signaling pathway, and affected the proliferation and differentiation of ISCs. These findings reveal the regulatory role of iron overload on the proliferation and differentiation of ISCs, providing a new insight into the internal mechanism of iron overload affecting intestinal health, and offering important theoretical basis for the scientific application of iron nutrition regulation.

miR-96-5p Induces Orbital Fibroblasts Differentiation by Targeting Smad7 and Promotes the Development of Thyroid-Associated Ophthalmopathy.

Background: Recent evidence shows that adipogenic differentiation of orbital fibroblasts (OFs) promotes the development of thyroid-associated ophthalmopathy (TAO), an organ-specific immune disease. Furthermore, miR-96-5p has been linked to adipogenic differentiation of C2C12 myoblasts and is significantly correlated with the severity of TAO. The purpose of this study is to look into the role of miR-96-5p in the adipogenesis of OFs with TAO. Methods: The orbital tissues from TAO patients and non-TAO participants were collected, and primary OFs were isolated and cultured for further analysis. miR-96-5p expression was examined using qRT-PCR. The adipogenic differentiation of OFs was then studied. Results: Orbital fibroblasts isolated from adipose tissues of TAO patients (t-OFs) demonstrated greater adipogenic differentiation ability than OFs isolated from adipose tissues of non-TAO participants. miR-96-5p was found to be overexpressed in the orbital tissues of TAO patients and t-OFs. Further research revealed that miR-96-5p, by targeting Smad7, could exacerbate PPAR-γ/C/EBPα signaling-induced adipogenic differentiation of t-OFs. However, inhibiting miR-96-5p could block t-OFs adipogenic differentiation-mediated adipogenesis via Smad7/PPAR-γ/C/EBPα. Conclusions: miR-96-5p plays a critical regulatory role in the development of TAO by targeting Smad7 and promoting adipogenic differentiation of OFs.