20.500.12556/RUL-179501 Hepatic management of toxic sterols after acute deletion of Cyp51 from cholesterol synthesis Lanosterol 14α-demethylase (CYP51), a key enzyme in cholesterol synthesis, is essential for normal liver function. Reduced CYP51 activity leads to metabolism-associated liver disease and ultimately hepatocellular carcinoma, yet the hepatocellular processes most affected and their crosstalk with other liver cell types remain poorly defined. Here, we present a new inducible, liver-specific Cyp51 knockout mouse model (iLKO) designed to study how acute disruption of cholesterol synthesis is managed in the adult liver. Doxycycline-inducible deletion minimizes developmental confounders of albumin-Cre models and enables isolation of viable primary hepatocytes. iLKO hepatocytes and liver tissue showed efficient CYP51 depletion with marked accumulation of lanosterol and 24,25-dihydrolanosterol, while hepatic cholesterol levels remained unchanged or only mildly reduced, indicating compensatory uptake and/or pathway rerouting. Histology and transmission electron microscopy (TEM) revealed hepatomegaly with mild portal inflammation, ductular reaction, endoplasmic reticulum (ER) dilation, mitochondrial swelling, and increased nuclear lipid droplets, consistent with adaptation to ER stress but without overt fibrosis at the studied time points. Notably, crystal-like inclusions - particularly in Kupffer cells - were observed. Although MALDI-TOF MS imaging could not determine their exact composition, their presence in the context of toxic sterol overload strongly suggests non-cholesterol sterol crystallization as a previously unrecognized trigger of inflammation. In summary, the iLKO model allows dissection of sterol toxicity independently of developmental effects and provides mechanistic insight into how disrupted cholesterol synthesis in adult hepatocytes initiates sterol-driven cellular stress and inflammation that predispose to metabolism-associated liver disease and hepatocellular carcinoma. CYP51 cholesterol metabolism crystals cytochrome P450 lanosterol 14α-demethylase lipid droplets liver mouse model sterol CYP51 presnova holesterola kristali citokrom P450 lanosterol 14α-demetilaza lipidne kapljice jetra mišji model sterol true false true Angleški jezik Slovenski jezik Članek v reviji 2026-02-16 08:57:31 2026-02-16 08:57:41 2026-05-18 11:29:56 0000-00-00 00:00:00 2026 0 0 17 str. iss. 3, art. 111188 Vol. 302 2026 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 577.2 1083-351X 10.1016/j.jbc.2026.111188 267520771 RAZ_Kreft_Tinkara_2026.pdf RAZ_Kreft_Tinkara_2026.pdf 1 BE0FCECBD8546ED8D352D67B2A3488C8 bdd9be9eafc5cbae9ac6f57d91f1ba756129bd0d21dcd139056f7229d56101fb 5a33d4ae-0b13-11f1-a1ba-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=228044 https://www.jbc.org/article/S0021-9258(26)00058-X/fulltext 1 f55c5a2d-0b0c-11f1-a1ba-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=228042 Medicinska fakulteta 0 0 0