Depression-related Testosterone Deficiency is Linked to Reduced Cholesterol Levels in Leydig Cells of CUMS Mice.

Testosterone deficiency in humans can be caused by depressive symptoms; however, the causes of this deficiency are incompletely understood. This study demonstrates that male mice with depression-like symptoms due to chronic unpredictable mild stress (CUMS) show reduced serum testosterone levels and disrupted sexual behaviors. However, the observed testosterone reductions were not caused by apoptosis of Leydig cells. Oil red O staining revealed that lipid droplets were dramatically decreased in Leydig cells, suggesting that defects in cholesterol uptake might be related to testosterone-deficiency in depression-like mice. To investigate the potential mechanism, lipid homeostasis was examined by liquid chromatography tandem mass spectrometry. The results revealed that higher levels of sphingomyelins (SM 8:0;2O/28:1, 18:0;2O/22:2, 33:0;3O, 33:1;2O) were linked to decreased cholesterol levels. Further investigation indicated that testosterone biosynthesis from cholesterol in Leydig cells was impaired by downregulation of Ldlr, SR-BI, LHR, and P450scc. Elevated levels of interferon signaling associated pathways in depression-like mice testes may also contribute to decreased testosterone level. Taken together, these findings provide a novel understanding of male reproductive problems under psychological stress and suggest that cholesterol uptake might be a causal factor in reduced testosterone production in depression-like mice.

SP1 mediates OGD/R-induced cardiomyocyte injury via enhancing the transcription of USP46.

BACKGROUND: One of the mechanisms responsible for the high mortality rate of acute myocardial infarction is myocardial ischemia-reperfusion injury (MI-RI). The present study focused on the role and regulatory mechanisms of specificity protein 1 (SP1) and ubiquitin-specific protease 46 (USP46) in oxygen-glucose deprivation/reperfusion (OGD/R)-induced cardiomyocyte injury. METHODS: OGD/R was used to treat cardiomyocytes AC16 to mimic ischemia-reperfusion in vitro. Cell viability, proliferation, and apoptosis were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, 5-ethynyl-2'-deoxyuridine, and flow cytometry assays. Enzyme-linked immunosorbent assays analyzed the concentrations of TNF-α and IL-1ß. Several protein levels were analyzed by western blotting. The levels of iron (Fe2+), reactive oxygen species, malondialdehyde, and the activities of superoxide dismutase were analyzed by commercial kits. Chromatin immunoprecipitation and dual-luciferase report assays assessed the relationship between USP46 and SP1. RESULTS: USP46 and SP1 were upregulated in serum from MI patients and they had a positive correlation. OGD/R stimulation suppressed cardiomyocyte viability and proliferation, as well as induced cardiomyocyte inflammation, oxidative stress (OxS) injury, apoptosis, and ferroptosis, but these effects were impaired by USP46 or SP1 knockdown. SP1 could enhance the transcription of USP46, and USP46 overexpression reversed SP1 silencing-mediated effects on OGD/R-induced cardiomyocytes. SP1 mediated the AMPK signaling via USP46. CONCLUSION: SP1 mediated OGD/R-induced cardiomyocyte inflammation, OxS injury, apoptosis, and ferroptosis by inactivating the AMPK signaling via enhancing the transcription of USP46.

Genomics of hybrid parallel origin in Aquilegia ecalcarata.

BACKGROUND: The parallel evolution of similar traits or species provides strong evidence for the role of natural selection in evolution. Traits or species that evolved repeatedly can be driven by separate de novo mutations or interspecific gene flow. Although parallel evolution has been reported in many studies, documented cases of parallel evolution caused by gene flow are scarce by comparison. Aquilegia ecalcarata and A. kansuensis belong to the genus of Aquilegia, and are the closest related sister species. Mutiple origins of A. ecalcarata have been reported in previous studies, but whether they have been driven by separate de novo mutations or gene flow remains unclear. RESULTS: In this study, We conducted genomic analysis from 158 individuals of two repeatedly evolving pairs of A. ecalcarata and A. kansuensis. All samples were divided into two distinct clades with obvious geographical distribution based on phylogeny and population structure. Demographic modeling revealed that the origin of the A. ecalcarata in the Eastern of China was caused by gene flow, and the Eastern A. ecalcarata occurred following introgression from Western A. ecalcarata population. Analysis of Treemix and D-statistic also revealed that a strong signal of gene flow was detected from Western A. ecalcarata to Eastern A. ecalcarata. Genetic divergence and selective sweep analyses inferred parallel regions of genomic divergence and identified many candidate genes associated with ecologically adaptive divergence between species pair. Comparative analysis of parallel diverged regions and gene introgression confirms that gene flow contributed to the parallel evolution of A. ecalcarata. CONCLUSIONS: Our results further confirmed the multiple origins of A. ecalcarata and highlighted the roles of gene flow. These findings provide new evidence for parallel origin after hybridization as well as insights into the ecological adaptation mechanisms underlying the parallel origins of species.

BRD4-specific PROTAC inhibits basal-like breast cancer partially through downregulating KLF5 expression.

Interest in the use of proteolysis-targeting chimeras (PROTACs) in cancer therapy has increased in recent years. Targeting bromodomain and extra terminal domain (BET) proteins, especially bromodomain-containing protein 4 (BRD4), has shown inhibitory effects on basal-like breast cancer (BLBC). However, the bioavailability of BRD4 PROTACs is restricted by their non-selective biodegradability and low tumor-targeting ability. We demonstrated that 6b (BRD4 PROTAC) suppresses BLBC cell growth by targeting BRD4, but not BRD2 and BRD3, for cereblon (CRBN)-mediated ubiquitination and proteasomal degradation. Compound 6b also inhibited expression of Krüppel-like factor 5 (KLF5) transcription factor, a key oncoprotein in BLBC, controlled by BRD4-mediated super-enhancers. Moreover, 6b inhibited HCC1806 tumor growth in a xenograft mouse model. The combination of 6b and KLF5 inhibitors showed additive effects on BLBC. These results suggest that BRD4-specific PROTAC can effectively inhibit BLBC by downregulating KLF5, and that 6b has potential as a novel therapeutic drug for BLBC.