UVB breaks the B-ring of 7-dehydrocholesterol leading to the formation of pre-vitamin D3 that either undergoes thermal isomerization to D3 or photoisomerization to lumisterol (L3) in a 9?,10?-configuration. L3 is the major photoisomer formed after prolonged exposure of the skin to UVB energy, in a process that is irreversible. L3 has been considered to be metabolically and biologically inactive with its formation explaining why UVB induced cutaneous production of pre-D3 does not lead to systemic intoxication by D3. Recently we found that L3 is metabolized by CYP11A1 to 22(OH)L3, 24(OH)L3, 20,22(OH)2D3 and pregnalumisterol (pL) [collectively called (OH)nL3]. Uning LC/qTOF-MS we demonstrated the presence of L3 in human serum at levels higher than D3, and detectable levels of (OH)nL3 in the epidermis and serum. Furthermore, we found that (OH)nL3 inhibits the proliferation of human epidermal keratinocytes and that 20(OH)L3 stimulates the expression of genes associated with keratinocyte differentiation and protection against oxidative stress. Our preliminary molecular modeling predicts that the major (OH)nL3 products can act on ROR? and ROR? showing favorable docking scores in the ligand binding domain (LBD) of the receptors, similar to known natural ligands. Supporting these predictions we found that 20(OH)L3 inhibits ROR? and ROR? transactivation activities in a Tet-on CHO cell reporter system, as well as reducing (RORE)-LUC reporter activity in skin cells. Thus, we have discovered a new lumisterogenic biochemical pathway that is biologically relevant. To investigate its role in skin physiology and pathology we formulate the hypothesis that skin-derived L3 is enzymatically activated generating (OH)nL3 compounds which regulate epidermal barrier and photoprotective functions through interaction with ROR? and ROR?. This hypothesis will be tested via three aims. 1. Defining ROR? and ROR? as functional receptors for novel hydroxylumisterol derivatives ((OH)nL3); 2. Defining the phenotypic activities of (OH)nL3 in cultured epidermal keratinocytes and in human skin histocultured ex vivo; 3. Defining the relative roles of ROR? and ROR? in (OH)nL3-mediated regulation of the differentiation program and protective mechanisms against UVB radiation in the epidermis. Our highly mechanistic strategy combines techniques of primary epidermal and organ cultures, in silico methods, cell-based transcriptional studies coupled to the LBD of ROR?/?, the use of genetically modified cells, whole genome RNA sequencing with bioinformatics, and the techniques of biochemistry, chemistry and molecular biology. This proposal is a comprehensive, multi- disciplinary and state-of-the-art investigation. Its significance encompasses defining a role for a previously unrecognized pathway of activation of an important UV photoproduct, L3, in skin physiology and pathology. The practical outcome of the realization of aims 1-3 would be the use of the most potent (OH)nL3 as agent(s) that either enhance the epidermal barrier or prevent or reverse damage inflicted by noxious stressors and UVB. Establishing roles for RORs in these processes will define them as druggable pharmacological targets.

Public Health Relevance

Following the surprising discovery that lumisterol, previously believed to be metabolically inactive, is transformed by CYP11A1 to biologically active hydroxy-derivatives which are detectable in the human serum and epidermis, we will define functions of these products in the skin using a highly mechanistic approach. This will include investigation on the mechanism of action of the derivatives, focusing on ROR? and ? signaling. We will define their roles in the keratinocyte differentiation program and test them as protectors of genomic and cellular integrity in the epidermis against UVB, the UVR spectrum responsible for the production of lumisterol.

National Institute of Health (NIH)
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Research Project (R01)
Project #
Application #
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Tseng, Hung H
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Alabama Birmingham
Schools of Medicine
United States
Zip Code
Slominski, Andrzej T; Zmijewski, Michal A; Plonka, Przemyslaw M et al. (2018) How UV Light Touches the Brain and Endocrine System Through Skin, and Why. Endocrinology 159:1992-2007
Slominski, Andrzej T; Hardeland, Ruediger; Zmijewski, Michal A et al. (2018) Melatonin: A Cutaneous Perspective on its Production, Metabolism, and Functions. J Invest Dermatol 138:490-499
Wasiewicz, Tomasz; Piotrowska, Anna; Wierzbicka, Justyna et al. (2018) Antiproliferative Activity of Non-Calcemic Vitamin D Analogs on Human Melanoma Lines in Relation to VDR and PDIA3 Receptors. Int J Mol Sci 19:
Singh, Bhupendra; Schoeb, Trenton R; Bajpai, Prachi et al. (2018) Reversing wrinkled skin and hair loss in mice by restoring mitochondrial function. Cell Death Dis 9:735
Skobowiat, Cezary; Bro?yna, Anna A; Janjetovic, Zorica et al. (2018) Melatonin and its derivatives counteract the ultraviolet B radiation-induced damage in human and porcine skin ex vivo. J Pineal Res 65:e12501
Tuckey, Robert C; Li, Wei; Ma, Dejian et al. (2018) CYP27A1 acts on the pre-vitamin D3 photoproduct, lumisterol, producing biologically active hydroxy-metabolites. J Steroid Biochem Mol Biol 181:1-10
Podgorska, Ewa; Drzal, Agnieszka; Matuszak, Zenon et al. (2018) Calcitriol and Calcidiol Can Sensitize Melanoma Cells to Low?LET Proton Beam Irradiation. Int J Mol Sci 19:
Jetten, Anton M; Takeda, Yukimasa; Slominski, Andrzej et al. (2018) Retinoic acid-related Orphan Receptor ? (ROR?): connecting sterol metabolism to regulation of the immune system and autoimmune disease. Curr Opin Toxicol 8:66-80
Cheng, Chloe Y S; Kim, Tae-Kang; Jeayeng, Saowanee et al. (2018) Properties of purified CYP2R1 in a reconstituted membrane environment and its 25-hydroxylation of 20-hydroxyvitamin D3. J Steroid Biochem Mol Biol 177:59-69
Tuckey, Robert C; Cheng, Chloe Y S; Slominski, Andrzej T (2018) The serum vitamin D metabolome: What we know and what is still to discover. J Steroid Biochem Mol Biol :

Showing the most recent 10 out of 18 publications