Obesity is recognized as a significant contributor to the onset of kidney disease. However, the key processes involved in the development of kidney disease in obese individuals are not well understood. Here, we investigated the effects of high-fat diet (HFD)-induced obesity on folic acid (FA)-induced kidney injury in mice. Mice were fed an HFD for 12 weeks to induce obesity, followed by an additional intraperitoneal injection of FA. The results showed that mice fed HFD developed higher levels of kidney damage than those in the chow group. In contrast, mice exposed to both HFD and FA showed less fibrosis and inflammatory responses compared to the FA only treated group. Furthermore, the HFD with FA group exhibited elevated lipid accumulation in the kidney and reduced expression of mitochondrial proteins compared to the FA-treated group. Under in vitro experimental conditions, we found that lipid accumulation induced by oleic acid treatment reduced inflammatory and fibrotic responses in both renal tubules and fibroblasts. Finally, RNA sequencing analysis revealed that the inflammasome and pyroptosis signaling pathways were significantly increased in the HFD group with FA injection. In summary, these findings suggest that obesity increases renal injury due to a lack of appropriate inflammatory, fibrotic, and metabolic responses and the activation of the inflammasome and pyroptosis signaling pathways.
