Mechanistic insights into how Prevotella copri exacerbates tissue iron retention and chronic inflammation in β-thalassemia mice via activation of the JAK/STAT signaling pathway

To investigate the effects of Prevotella copri ( P. copri ) on iron overload and chronic inflammation in β-thalassemia (β-Thal) mice, and to elucidate its underlying molecular mechanisms. 1. Fecal samples from wild-type (WT) and β-Thal mice were subjected to 16S rRNA sequencing to analyze differences in intestinal microbiota composition. 2. Given that P. copri acts as a dominant pro‑inflammatory bacterium in β‑Thal mice, four experimental groups were established: WT, WT+ P. copri , β‑Thal, and β‑Thal+ P. copri . Following intragastric gavage transplantation of P. copri , the following detections were performed: serum levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), interleukin-10 (IL-10), erythropoietin (EPO), serum ferritin (SF), and ferroportin (FPN) were quantified using enzyme-linked immunosorbent assay (ELISA) kits; hematopoietic function was evaluated via routine blood test and reticulocyte (Ret) measurement; mRNA and protein expression levels of glycoprotein 130 (Gp130), Janus kinase 1 (JAK1), phosphorylated Janus kinase 1 (p-JAK1), signal transducer and activator of transcription 3 (STAT3), and phosphorylated signal transducer and activator of transcription 3 (p-STAT3) were determined by quantitative real-time reverse transcription polymerase chain reaction (qPCR) and Western blot; colonic tissue morphology was observed via hematoxylin-eosin (HE) staining; and iron deposition in the liver and spleen was assessed using Prussian blue staining. Compared with the β-Thal group, the β-Thal+ P. copri group exhibited elevated levels of pro-inflammatory factors (TNF-α, IL-1β, IL-6), decreased IL-10, increased SF and reduced FPN ( p < 0.05); hemoglobin (Hb) was decreased, while EPO and Ret were increased ( p < 0.05); the expression levels of GP130, p-JAK1/JAK1 and p-STAT3/STAT3 were upregulated; colonic mucosal damage accompanied by inflammatory cell infiltration, as well as markedly aggravated iron granule deposition in the liver and spleen were observed. P. copri exacerbates iron overload by triggering inflammatory responses and upregulating hepcidin in β-Thal mice, and this effect may be attributed to P. copri -mediated elevation of IL-6 and subsequent activation of the JAK/STAT signaling pathway. P. copri may further aggravate ineffective erythropoiesis and erythrocyte injury in β-Thal mice.