Bone marrow mesenchymal stem cell-derived exosomal miR-30e-5p ameliorates high-glucose induced renal proximal tubular cell pyroptosis by inhibiting ELAVL1

BACKGROUND

The rapid increase in the prevalence of diabetes has resulted in more cases of diabetic kidney disease (DKD). Treatment with bone marrow mesenchymal stem cells (BMSCs) may represent an alternative strategy to manage DKD.

METHODS

HK-2 cells were treated with 30 mM high glucose (HG). Bone marrow MSC-derived exosomes (BMSC-exos) were isolated and internalized into HK-2 cells. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) and lactate dehydrogenase (LDH) assays were used to measure viability and cytotoxicity. The secretion of IL-1β and IL-18 was measured by ELISA. Pyroptosis was assessed by flow cytometry. Quantitative RT-PCR was used to measure the levels of miR-30e-5p, ELAV like RNA binding protein 1 (ELAVL1), IL-1β, and IL-18. The expression of ELAVL1 and pyroptosis-associated cytokine proteins was determined by western blot analysis. A dual-luciferase reporter gene assay was conducted to confirm the relationship between miR-30e-5p and ELAVL1.

RESULTS

BMSC-exos decreased LDH, IL-1β, and IL-18 secretion and inhibited the expression of the pyroptosis-related factors (IL-1β, caspase-1, GSDMD-N, and NLRP3) in HG-induced HK-2 cells. Moreover, miR-30e-5p depletion derived from BMSC-exos promoted HK-2 cell pyroptosis. Besides, miR-30e-5p over-expression or ELVAL1 knockdown could directly inhibit pyroptosis. ELAVL1 was a target of miR-30e-5p and knocking down ELAVL1 reversed the effect of miR-30e-5p inhibition in BMSC-exos-treated HK-2 cells.

CONCLUSIONS

BMSC-derived exosomal miR-30e-5p inhibits caspase-1-mediated pyroptosis by targeting ELAVL1 in HG-induced HK-2 cells, which might provide a new strategy for treating DKD.

Geniposide accelerates proteasome degradation of Txnip to inhibit insulin secretion in pancreatic β-cells

PURPOSE

To analyze the role of geniposide in the protein degradation of Txnip and to determine the impact of Txnip on geniposide-regulated GSIS in pancreatic INS-1 cells.

METHODS

The content of Txnip protein was measured by western blot; insulin content and glucose uptake were determined by ELISA; and knockdown of Txnip was the method of RNA interference.

RESULTS

Glucose induces a rapid increase in Txnip protein, and geniposide accelerates the degradation of Txnip via proteasome pathway in the presence of high glucose (25 mM) in INS-1 pancreatic β-cells. And MG132, a proteasomal inhibitor, potentiates glucose uptake, metabolism (ATP production) and glucose-stimulated insulin secretion (GSIS) in high-glucose (25 mM)-treated INS-1 cells, but geniposide significantly prevents these effects. Furthermore, the combination of geniposide and Txnip knockdown shows substantial synergistic effects to reduce glucose uptake, metabolism and GSIS in high-glucose (25 mM)-treated INS-1 cells.

CONCLUSIONS

Txnip protein played an essential role in glucose uptake, metabolism and GSIS, and geniposide could accelerate the degradation via proteasome pathway in high-glucose-treated pancreatic INS-1 cells.