Defects in cholesterol synthesis genes in mouse and in humans: lessons for drug development and safer treatments
DRUG METABOLISM REVIEWS
Authors: Horvat, Simon; Mcwhir, Jim; Rozman, Damjana
Abstract
This review describes the mouse knockout models of cholesterol synthesis, together with human malformations and drugs that target cholesterogenic enzymes. Generally, the sooner a gene acts in cholesterol synthesis, the earlier the phenotype occurs. Humans with loss of function of early cholesterogenic enzymes have not yet been described, and in the mouse, loss of Hmgcr is preimplantation lethal. Together, these results indicate that the widely prescribed cholesterol-lowering statins are potentially teratogenic. The Mvk knockout is early embryonic lethal in the mouse, the absence of Fdft1 is lethal at E9.5-12.5 dpc, while the Cyp51 knockouts die at 15.0 dpc. Fungal CYP51 inhibitor azoles are teratogenic in humans, potentially leading to symptoms of Antley-Bixler syndrome. The X-linked mutations in Nsdhl and Ebp are embryonic lethal in male mice, while heterozygous females are also affected. Consequently, the anticancer drugs, tamoxifen and toremifene, inhibiting human EBP, may be harmful in early pregnancy. The Dhcr7 and Dhcr24 knockout mice die shortly after birth, while humans survive with Smith-Lemli-Opitz syndrome or desmosterolosis. Since cholesterol is essential for hedgehog signaling, disturbance of this pathway by antipsychotics and-depressants explains some drug side effects. In conclusion, defects in cholesterol synthesis are generally lethal in mice, while humans with impaired later steps of the pathway can survive with severe malformations. Evidence shows that drugs targeting or, by coincidence, inhibiting human cholesterol synthesis are better avoided in early pregnancy. Since some drugs with teratogenic potential still stay on the market, this should be avoided in new cholesterol-related drug development.
Association of polymorphisms in GCKR and TRIB1 with nonalcoholic fatty liver disease and metabolic syndrome traits
ENDOCRINE JOURNAL
Authors: Kitamoto, Aya; Kitamoto, Takuya; Nakamura, Takahiro; Ogawa, Yuji; Yoneda, Masato; Hyogo, Hideyuki; Ochi, Hidenori; Mizusawa, Seiho; Ueno, Takato; Nakao, Kazuwa; Sekine, Akihiro; Chayama, Kazuaki; Nakajima, Atsushi; Hotta, Kikuko
Abstract
In several genome-wide association studies, nonalcoholic fatty liver disease and alanine aminotransferase susceptibility variants have been identified in several genes, including LYPLAL1, ZP4, GCKR, HSD17B13, PALLD, PPP1R3B, FDFT1, TRIB1, COL13A1, CPNI, ERLIN1, CWF19L1, EFCAB4B, PZP, and NCAN. To investigate the relationship between these genes and nonalcoholic fatty liver disease in the Japanese population, we genotyped 540 patients and 1012 control subjects for 18 variations. We performed logistic regression analyses to characterize the association between the tested variations and nonalcoholic fatty liver disease. Metabolic syndrome and histological traits were also analyzed by linear regression. We also examined GCKR rs780094, TRIB1 rs2954021, and PNPLA3 rs738409 for epistatic effects. The A-allele of rs780094 in GCKR (P = 0.0024) and the A-allele of rs2954021 TRIB1 (P = 4.5x10(-5)) were significantly associated with nonalcoholic fatty liver disease. GCKR rs780094 was also associated with decreased plasma glucose, and increased triglycerides in the patient and control groups. GCKR rs780094 was also associated with an increased ratio of visceral to subcutaneous fat area in the patients with nonalcoholic fatty liver disease. Variations in GCKR, TRIB1, and PNPLA3 independently influenced nonalcoholic fatty liver disease and had no epistatic effects. Our data suggest variations in GCKR and TRIB1 are involved in the development of nonalcoholic fatty liver disease.