Hair and Skin Sterols in Normal Mice and Those with Deficient Dehydrosterol Reductase (DHCR7), the Enzyme Associated with Smith-Lemli-Opitz Syndrome
Overview
Molecular Biology
Affiliations
Our recent studies have focused on cholesterol synthesis in mouse models for 7-dehydrosterolreductase (DHCR7) deficiency, also known as Smith-Lemli-Opitz syndrome. Investigations of such mutants have relied on tissue and blood levels of the cholesterol precursor 7-dehydrocholesterol (7DHC) and its 8-dehydro isomer. In this investigation by gas chromatography/mass spectrometry (GC/MS) we have identified and quantified cholesterol and its precursors (7DHC, desmosterol, lathosterol, lanosterol and cholest-7,24-dien-3β-ol) in mouse hair. The components were characterized and their concentrations were compared to those found in mouse skin and serum. Hair appeared unique in that desmosterol was a major sterol component, almost matching in concentration cholesterol itself. In DHCR7 deficient mice, dehydrodesmosterol (DHD) was the dominant hair Δ(7) sterol. Mutant mouse hair had much higher concentrations of 7-dehydrosterols relative to cholesterol than did serum or tissue at all ages studied. The 7DHC/C ratio in hair was typically about sevenfold the value in serum or skin and the DHD/D ratio was 100× that of the serum 7DHC/C ratio. Mutant mice compensate for their DHCR7 deficiency with maturity, and the tissue and blood 7DHC/C become close to normal. That hair retains high relative concentrations of the dehydro precursors suggests that the apparent up-regulation of Dhcr7 seen in liver is slower to develop at the site of hair cholesterol synthesis.
Luo Y, Zhang C, Ma L, Zhang Y, Liu Z, Chen L J Lipid Res. 2022; 63(6):100228.
PMID: 35577137 PMC: 9207299. DOI: 10.1016/j.jlr.2022.100228.
Mack Y, Dehari M, Morooka N, Nagata S Insects. 2021; 12(9).
PMID: 34564222 PMC: 8471071. DOI: 10.3390/insects12090782.
Wang H, Humbatova A, Liu Y, Qin W, Lee M, Cesarato N Am J Hum Genet. 2020; 107(1):34-45.
PMID: 32497488 PMC: 7332643. DOI: 10.1016/j.ajhg.2020.05.006.
Romano M, Tafazzoli A, Mattern M, Sivalingam S, Wolf S, Rupp A Am J Hum Genet. 2018; 103(5):777-785.
PMID: 30401459 PMC: 6218848. DOI: 10.1016/j.ajhg.2018.09.011.
JunB defines functional and structural integrity of the epidermo-pilosebaceous unit in the skin.
Singh K, Camera E, Krug L, Basu A, Pandey R, Munir S Nat Commun. 2018; 9(1):3425.
PMID: 30143626 PMC: 6109099. DOI: 10.1038/s41467-018-05726-z.