The Tm7sf2 Gene Deficiency Protects Mice against Endotoxin-Induced Acute Kidney Injury

Cholesterol is essential for diverse cellular functions and cellular and whole-body cholesterol
homeostasis is highly controlled. Cholesterol can also influence cellular susceptibility to injury.
The connection between cholesterol metabolism and inflammation is exemplified by the
Tm7sf2 gene, the absence of which reveals an essential role in cholesterol biosynthesis under
stress conditions but also results in an inflammatory phenotype, i.e. NF-κB activation and
TNFα up-regulation. Here, by using Tm7sf2+/+and Tm7sf2−/− mice, we investigated whether
the Tm7sf2 gene, through its role in cholesterol biosynthesis under stress conditions, is
involved in the renal failure induced by the administration of LPS. We found that the loss of
Tm7sf2 gene results in significantly reduced blood urea nitrogen levels accompanied by
decreased renal inflammatory response and neutral lipid accumulation. The increased expression
of fatty acids catabolic enzymes reduces the need of the renal autophagy, a known crucial
nutrient-sensing pathway in lipid metabolism. Moreover, we observed that the Tm7sf2 insufficiency
is responsible for the inhibition of the NF-κB signalling thus dampening the inflammatory
response and leading to a reduced renal damage. These results suggest a pivotal role for
Tm7sf2 in renal inflammatory and lipotoxic response under endotoxemic conditions.