Curcumin alleviated dextran sulfate sodium-induced colitis by recovering memory Th/Tfh subset balance

BACKGROUND

Restoration of immune homeostasis by targeting the balance between memory T helper (mTh) cells and memory follicular T helper (mTfh) cells is a potential therapeutic strategy against ulcerative colitis (UC). Because of its anti-inflammatory and immunomodulatory properties, curcumin (Cur) is a promising drug for UC treatment. However, fewer studies have demonstrated whether Cur can modulate the mTh/mTfh subset balance in mice with colitis.

AIM

To explore the potential mechanism underlying Cur-mediated alleviation of colitis induced by dextran sulfate sodium (DSS) in mice by regulating the mTh and mTfh immune homeostasis.

METHODS

Balb/c mice were administered 3% and 2% DSS to establish the UC model and treated with Cur (200 mg/kg/d) by gavage on days 11-17. On the 18th d, all mice were anesthetized and euthanized, and the colonic length, colonic weight, and colonic weight index were evaluated. Histomorphological changes in the mouse colon were observed through hematoxylin-eosin staining. Levels of Th/mTh and Tfh/mTfh cell subsets in the spleen were detected through flow cytometry. Western blotting was performed to detect SOCS-1, SOCS-3, STAT3, p-STAT3, JAK1, p-JAK1, and NF-κB p65 protein expression levels in colon tissues.

RESULTS

Cur effectively mitigates DSS-induced colitis, facilitates the restoration of mouse weight and colonic length, and diminishes the colonic weight and colonic weight index. Simultaneously, it hinders ulcer development and inflammatory cell infiltration in the colonic mucous membrane. While the percentage of Th1, mTh1, Th7, mTh7, Th17, mTh17, Tfh1, mTfh1, Tfh7, mTfh7, Tfh17, and mTfh17 cells decreased after Cur treatment of the mice for 7 d, and the frequency of mTh10, Th10, mTfh10, and Tfh10 cells in the mouse spleen increased. Further studies revealed that Cur administration prominently decreased the SOCS-1, SOCS-3, STAT3, p-STAT3, JAK1, p-JAK1, and NF-κB p65 protein expression levels in the colon tissue.

CONCLUSION

Cur regulated the mTh/mTfh cell homeostasis to reduce DSS-induced colonic pathological damage, potentially by suppressing the JAK1/STAT3/SOCS signaling pathway.

MiR-17-5p modulates mitochondrial function of the genioglossus muscle satellite cells through targeting Mfn2 in hypoxia

The root cause of obstructive sleep apnea-hypopnea syndrome (OSAHS) is repeated hypoxia during sleep. The genioglossus is one of the most important upper airway dilatation muscles and is important for maintaining normal oxygen supply during sleep. Hypoxia can directly affect the energy metabolism level of the genioglossus muscle, thereby weakening muscle function. MicroRNAs (miRNAs) can regulate mitochondrial function at the post-transcriptional level and achieve recovery or even enhancement of genioglossus function, but the specific mechanism is still unclear. In this study, an intermittent hypoxic cell model was established to detect the effects of hypoxia on the proliferation and apoptosis of Genioglossus muscle satellite cells (GG MuSCs), and the damage to the mitochondrial structure and function was assessed by transmission electron microscopy and mitochondrial membrane potential. Then, miR-17-5p was upregulated and downregulated by miRNA mimics and inhibitors, respectively, and bioinformatics analysis was used to predict and validate the target genes of miR-17-5p. The results showed that the hypoxic environment affected the proliferation of GG MuSCs and mitochondrial membrane potential, which promoted the occurrence of apoptosis and mitochondrial edema. After upregulation of miR-17-5p, cell proliferative capacity and mitochondrial function were restored. Bioinformatics prediction and gene and protein level analyses found that Mfn2 may be a target gene of miR-17-5p. .