ABSTRACT
Background: Insulin resistance has been implicated in the pathogenesis of children born small for gestational age (SGA) with catch-up growth (CUG). Adipose tissue macrophages (ATMs) regulate insulin resistance by secreting exosomes containing microRNA (miRNA) cargo; however, their pathogenic roles and molecular mechanism are not fully understood. This study aimed to investigate the role of miR-210-5p in rats born SGA with CUG and insulin resistance. Methods: The dietary needs of pregnant rats were restricted to ensure the birth of SGA rats. Transmission electron microscopy (TEM) and Western blot analysis were used to identify the exosomes from ATMs of CUG-SGA and adequate-for-gestational-age (AGA) rats. PKH-67 staining was performed to confirm the uptake of exosomes. miR-210-5p expression was measured by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Glucose uptake and output were detected with glucose uptake and output assays, respectively. Insulin resistance was detected with glucose and insulin tolerance tests in vivo. The interaction between miR-210-5p and SID1 transmembrane family member 2 (SIDT2) was validated with dual-luciferase reporter assay. Results: miR-210-5p was observed to be highly expressed in the exosomes derived from the ATMs of CUG-SGA rats. ATM-derived exosomes can serve as vehicles to deliver miR-210-5p into adipocytes, myocytes, and hepatocytes, where it can enhance cellular insulin resistance. SIDT2 was identified as a direct target gene of miR-210-5p. The miR-210-5p-induced insulin resistance was reversed by the restored SIDT2 expression. However, overexpression of SIDT2 abolished the inhibitory effect of CUG-SGA-ATM-exosomal miR-210-5p on insulin sensitivity in vivo. Conclusions: ATM-derived exosomal miR-210-5p promoted insulin resistance in CUG-SGA rats by targeting SIDT2, which may act as a new potential therapeutic target for children born SGA with CUG.
ABSTRACT
Multiple sclerosis (MS) is a common autoimmunity disease of the central nervous system (CNS) that mostly happens in young adults. The chronic clinical features of MS include inflammatory demyelination, infiltration of immune cells, and secretion of inflammatory cytokines, which have been proved to be associated with CD4+ T cells. Ferroptosis is a newly discovered programmed cell death mediated by the massive lipid peroxidation and more sensitive to CD4+ T cells. However, the effect of ferroptosis of CD4+ T cells on the occurrence and progression of MS retains unclear. Here, the experimental autoimmune encephalomyelitis (EAE) model was used to investigate the role of GPX4, a leading inhibitor of ferroptosis, which plays in the function of CD4+ T cells. Our results showed that GPX4 was highly expressed in CD4+ T cells of MS patients based on existing databases. Strikingly, conditional knockout of GPX4 in CD4cre mice (cKO mice) significantly alleviated the average symptom scores and immunopathology of EAE. The infiltration of immune cells, including CD4+ T and CD8+ T cells, and the generation of GM-CSF, TNF-α, and IL-17A, were remarkably reduced in the CNS from cKO mice compared with WT mice. These findings further revealed the vital role of GPX4 in the expansion and function of CD4+ T cells. Moreover, GPX4-deficient CD4+ T cells were susceptible to ferroptosis in EAE model. Overall, this study provided novel insights into therapeutic strategies targeting GPX4 in CD4+ T cells for inhibiting CNS inflammation and treating MS.
