Mincle Maintains M1 Polarization of Macrophages and Contributes to Renal Aging Through the Syk/NF-κB Pathway

Abstract

Kidney is a classic organ undergoing senescence, and chronic inflammation has an important effect in cellular senescence. Mincle has been shown to be vital for maintaining the M1 phenotype of macrophages, but its role in regulating renal aging has yet to be explored. Young (2 months of age) and old (24 months of age) mice were used to analyze the changes of kidney damage during natural aging. Mice were subcutaneously injected with D-galactose (D-gal) to establish a renal aging model, and miR-6948-3p mimic and Mincle siRNA were administered via the tail vein every 3 days. Aged kidney and experimental aging kidney were characterized by decreased renal function and structural damage, and upregulated expression of senescence-related proteins and SPAP components. The ratio of M1 macrophages was increased in the aged kidney, and Mincle accumulated in the aged kidney macrophages. Administration of miR-6948-3p mimic or Mincle siRNA alleviated D-gal-induced renal senescence. LPS was used to induce M1 polarization of bone marrow-derived macrophages, and a coculture system of M1 macrophages and mouse renal tubular epithelial cells (TCMK-1) was established. Mincle was upregulated in LPS-induced M1 macrophages in vitro, and silencing Mincle in M1 macrophages attenuated M1 macrophage-induced TCMK-1 cell senescence. Mechanistically, Mincle was regulated by miR-6948-3p and maintained the M1 phenotype of macrophages through the Syk/NF-κB pathway. In conclusion, Mincle, posttranscriptionally suppressed by miR-6948-3p, modulated renal senescence by maintaining the phenotype of M1 macrophages through the Syk/NF-κB pathway.