Journal of Steroid Biochemistry and Molecular Biology最新文献

The vitamin D receptor (Vdr) and calcium-sensing receptor (Casr) regulate epidermal proliferation and differentiation. Deletion of both Vdr and Casr from Krt14 expressing epidermal keratinocytes (DKO) causes alopecia and delays wound re-epithelialization. Here, we demonstrate that DKO mice spontaneously develop squamous cell carcinoma with aging. We investigated the molecular mechanisms by which loss of Vdr/Casr leads to epidermal tumorigenesis. Ingenuity Pathway Analysis (IPA) predicted oxidative stress as a major pathway driving the biological processes resulting from Vdr/Casr deficiency. DKO keratinocytes showed reduced expression of genes involved in oxidative stress responses in neonatal epidermis, occurring prior to tumor formation. Spatial transcriptomic (Xenium) analysis demonstrated that reactive oxygen-metabolizing enzymes were markedly decreased in the supra-basal epidermal layers at the skin surface, consistent with differentiation defects caused by Vdr/Casr loss. These reductions were also evident in cells from the lower portion of the hair follicle, the infundibulum, which may arise from epidermal fate transformation toward sebaceous cells. Expression of DNA repair genes, including Xpc and Gadd45a, both implicated in epidermal tumorigenesis, was also decreased following Vdr/Casr deletion. Consistently, DKO keratinocytes exhibited impaired oxidative stress responses and reduced DNA repair capacity. Vdr/Casr deficiency prolonged UVB-induced reactive oxygen species and delayed clearance of UV-induced pyrimidine (6-4) pyrimidone photoproducts. Together, these findings suggest that DKO predisposes supra-basal epidermal cells and infundibulum-derived hair follicle stem cells to malignant transformation by impairing their ability to mitigate oxidative stress and DNA repair process.

Thermal processing of foods promotes cholesterol oxidation, leading to the formation of 7-ketocholesterol (7-K), a major secondary oxysterol generated through radical- and photo-oxidative mechanisms. Cooking technologies differently affect its accumulation, depending on temperature/time combinations, oxygen exposure, moisture loss, and matrix characteristics (lipid composition, endogenous antioxidants, pre-treatments). Dry-heat methods (such as grilling, roasting, pan-frying and deep-frying) generally intensify oxidation, while microwaving may further accelerate hydroperoxide degradation and interface-driven radical reactions. Conversely, vacuum-based low-temperature systems (such as sous-vide) may lead to lower 7-K formation. However, post-cooking conditions (including storage, reheating, and warm holding) can significantly enhance 7-K production, especially in PUFA-rich matrices and products previously subjected to oxidative stress. Considering that 7-K is absorbed to a limited extent but can reach systemic circulation, the evaluation of dietary exposure to 7-K present in commonly consumed cooked foods is relevant for assessing its potential contribution to diet-related oxidative burden. This review compiles current knowledge on formation mechanisms, technological drivers, and dietary occurrence of 7-K in thermally processed foods, highlighting key factors influencing its development across cooking methods.

The gonadotropin system plays a fundamental role in regulating teleost reproduction. This study characterizes the molecular properties and physiological functions of the Gth system in the mandarin fish (Siniperca chuatsi). Sequence analysis reveals that both fshb and lhb subunits possess a single N-glycosylation site. Phylogenetic evidence indicates that the lhcgr duplication occurred prior to the teleost specific whole genome duplication event. Tissue distribution analysis demonstrates that lhcgr2 is strictly gonad-specific, while lhcgr1 exhibits a broad distribution across multiple organs, including the brain and liver. Furthermore, the spatiotemporal expression profiles delineate a clear regulatory sequence during gonadal development. At the molecular differentiation stage (15 days post hatching, dph), the significant upregulation of fshr and lhcgrs in males precedes histological gonadal differentiation at 30 dph. During the initiation of gametogenesis at 60 dph a distinct sexual dimorphism emerges. Female development is characterized by a significant increase in pituitary fshb to drive follicle recruitment. In contrast, male development relies on a receptor sensitization mechanism, where early endogenous androgens upregulate gonadal fshr and lhcgrs to sustain spermatogenesis through to sexual maturity at 360 dph. Additionally, experimental hormonal treatments confirm that androgens induce a male-biased receptor expression pattern, whereas estrogens suppress it. Pharmacological assays further identify a biased preference of Fshr for the MAPK pathway and prominent constitutive activity of Lhcgr2. Collectively, these findings provide a comprehensive model for the endocrine regulation of the male developmental trajectory in the mandarin fish.

20α-Hydroxyprogesterone (20α-DHP) is an endogenous progestogenic metabolite of progesterone, biosynthesized primarily through the catalytic action of 20α-hydroxysteroid dehydrogenase (20α-HSD). To screen for highly active 20α-HSDs, five enzymes derived from phylogenetically diverse species-human, orangutan, mouse, bovine, and porcine-were systematically evaluated using multiple sequence alignment, molecular docking, and molecular dynamics simulations. The corresponding genes were subsequently expressed heterologously in E. coli BL21(DE3), and activity screening identified the human-derived 20α-HSD as the superior candidate. Enzymatic characterization revealed maximal activity at pH 8.0 and 35°C, negligible sensitivity to metal ions, and high substrate affinity and catalytic efficiency. Expression conditions were further optimized, with 0.2 mM IPTG at 20°C for 20 h established as the optimal induction parameters. Systematic optimization of reaction parameters-including organic solvent types and optimal concentration of the organic solvent, catalytic time, NADPH concentration, and recombinase concentration -achieved a progesterone conversion rate of 66.75%. To minimize cofactor consumption and enhance process economics, a glucose dehydrogenase-mediated NADPH in situ regeneration system was constructed, sustaining a conversion rate of 64.62%. Scale-up to a 100 mL preparative reaction yielded a conversion rate of 60.83%. Following column chromatography purification, 20α-DHP was isolated in 45.36% yield with 95% purity, as confirmed by HPLC and ¹H NMR analyses. In summary, this study achieved the successful heterologous expression of 20α-HSD in E. coli and established an efficient, green, and highly selective biosynthetic route for 20α-DHP, providing a viable technical foundation for its potential industrial-scale production.