Bovine serum albumin aggravates macrophage M1 activation and kidney injury in heterozygous Klotho-deficient mice via the gut microbiota-immune axis

Klotho expression abnormalities induces kidney injury and chronic kidney disease, however, the underlying mechanism remains unclear. Here, Klotho+/mice and wild-type mice were treated with low-dose bovine serum albumin (BSA). Pathological examination demonstrated that the area of glomerular collagen deposition and fibrosis in BSA-Kl(-/+) mice was significantly larger than that in BSA-WT mice. The serum levels of superoxide dismutase, malondialdehyde, creatinine, and urea in BSA-Kl(-/+) mice were significantly increased. Sequencing of gut microbiota 16S rRNA v3-v4 region indicated that BSA-Kl(-/+) mice showed a significantly higher relative abundance of the genera Dubosiella, Akkermansia, Alloprevotella, and Lachnospiraceae and a significantly lower relative abundance of the genera Allobaculum and Muribaculaceae than BSA-WT mice. KEGG analysis revealed that the metabolic pathways of signal transduction, xenobiotic biodegradation and metabolism, and lipid metabolism increased significantly in BSA-Kl(-/+) mice. Flow cytometry showed that the proportion of CD68(+)/CD11b(+) cells in the peripheral blood was significantly higher in BSA-KL-/+ mice than that in BSA-WT mice. qPCR and western blot suggested that Klotho and Nrf2 expression in M phi 1 cells of BSA-KL-/+ mice was significantly decreased. Thus, the findings suggest during the immune activation and chronic inflammation induced by the gut microbiota imbalance in Klotho-deficient mice treated to BSA, disrupted expression of proteins in the Nrf2/NF-kappa B signaling pathway in monocyte-derived macrophage M1 cells leads to the aggravation of inflammation and kidney injury.

Automated summary

The study shows that abnormalities in Klotho expression can lead to kidney injury and chronic kidney disease, potentially due to immune activation and chronic inflammation induced by gut microbiota imbalance.