Androgens promote vascular endothelial cell proliferation through activation of a ZIP9-dependent inhibitory G protein/PI3K-Akt/Erk/cyclin D1 pathway

Novel Plasma Membrane Androgen Receptor SLC39A9 Mediates Ovulatory Changes in Cells of the Monkey Ovarian Follicle

Follicular androgens are important for successful ovulation and fertilization. The classical nuclear androgen receptor (AR) is a transcription factor expressed in the cells of the ovarian follicle. Androgen actions can also occur via membrane androgen receptor SLC39A9. Studies in fish ovary demonstrated that androgens bind to SLC39A9 and increase intracellular zinc to regulate ovarian cell function. To determine if SLC39A9 is expressed and functional in the key cell types of the mammalian ovulatory follicle, adult female cynomolgus macaques underwent ovarian stimulation. Ovaries or ovarian follicular aspirates were harvested at 0, 12, 24, and 36 hours after human chorionic gonadotropin (hCG). SLC39A9 and AR mRNA and protein were present in granulosa, theca, and vascular endothelial cells across the entire 40-hour ovulatory window. Testosterone, bovine serum albumin-conjugated testosterone (BSA-T), and androstenedione stimulated zinc influx in granulosa, theca, and vascular endothelial cells. The SLC39A9-selective agonist (-)-epicatechin also stimulated zinc influx in vascular endothelial cells. Taken together, these data support the conclusion that SLC39A9 activation via androgen induces zinc influx in key ovarian cells. Testosterone, BSA-T, and androstenedione each increased proliferation in vascular endothelial cells, indicating the potential involvement of SLC39A9 in ovulatory angiogenesis. Vascular endothelial cell migration also increased after treatment with testosterone, but not after treatment with BSA-T or androstenedione, suggesting that androgens stimulate vascular endothelial cell migration through nuclear AR but not SLC39A9. The presence of SLC39A9 receptors and SLC39A9 activation by follicular androstenedione concentrations suggests that androgen activation of ovarian SLC39A9 may regulate ovulatory changes in the mammalian follicle.

Anabolic Steroids Activate the NF-κB Pathway in Porcine Ovarian Putative Stem Cells Independently of the ZIP-9 Receptor

Boldenone (Bdn) and nandrolone (Ndn) are anabolic androgenic steroids (AASs) that, as our previous studies have shown, may increase the risk of neoplastic transformation of porcine ovarian putative stem cells (poPSCs). The NF-κB pathway may be important in the processes of carcinogenesis and tumour progression. Therefore, in this work, we decided to test the hypothesis of whether Bdn and Ndn can activate the NF-κB pathway by acting through the membrane androgen receptor ZIP-9. For this purpose, the expression profiles of both genes involved in the NF-κB pathway and the gene coding for the ZIP-9 receptor were checked. The expression and localization of proteins of this pathway in poPSCs were also examined. Additionally, the expression of the ZIP-9 receptor and the concentration of the NF-κB1 and 2 protein complex were determined. Activation of the NF-κB pathway was primarily confirmed by an increase in the relative abundances of phosphorylated forms of RelA protein and IκBα inhibitor. Reduced quantitative profiles pinpointed not only for genes representing this pathway but also for unphosphorylated proteins, and, simultaneously, decreased concentration of the NF-κB1 and 2 complex may indicate post-activation silencing by negative feedback. However, the remarkably and sustainably diminished expression levels noticed for the SLC39A9 gene and ZIP-9 protein suggest that this receptor does not play an important role in the regulation of the NF-κB pathway.

Sex differences in vascular endothelial cells

Endothelial cells are important constituents of blood vessels and play a critical role in vascular homeostasis. They do not only control the exchanges between the blood and the surrounding tissues, but are also essential in regulating blood flow, modulating immune-cell trafficking and controlling vascular growth and repair. Endothelial dysfunction leads to cardiovascular diseases and is characterized by deficiency in secretion of vasodilator molecules, elevated reactive oxygen species (ROS), expression of adhesion molecules and excretion of proinflammatory cytokines. The sex hormones, estrogens, androgens and progestogens, regulate endothelial functions. Because cardiovascular disease risk increases after menopause, it is believed that female hormones, estrogens and progestogens promote endothelial cell health and function whereas androgens, the male hormones, might be detrimental. However, as illustrated in the present review, the picture might not be that simple. In addition, sex influences endothelial cell physiology independently of sex hormones but at genetic level.

ZIP9 mediates the effects of DHT on learning, memory and hippocampal synaptic plasticity of male Tfm and APP/PS1 mice

Androgens are closely associated with functions of hippocampal learning, memory, and synaptic plasticity. The zinc transporter ZIP9 (SLC39A9) regulates androgen effects as a binding site distinct from the androgen receptor (AR). However, it is still unclear whether androgens regulate their functions in hippocampus of mice through ZIP9. Compared with wild-type (WT) male mice, we found that AR-deficient male testicular feminization mutation (Tfm) mice with low androgen levels had learning and memory impairment, decreased expression of hippocampal synaptic proteins PSD95, drebrin, SYP, and dendritic spine density. Dihydrotestosterone (DHT) supplementation significantly improved these conditions in Tfm male mice, although the beneficial effects disappeared after hippocampal ZIP9 knockdown. To explore the underlying mechanism, we first detected the phosphorylation of ERK1/2 and eIF4E in the hippocampus and found that it was lower in Tfm male mice than in WT male mice, it upregulated with DHT supplementation, and it downregulated after hippocampal ZIP9 knockdown. Next, we found that the expression of PSD95, p-ERK1/2, and p-eIF4E increased in DHT-treated mouse hippocampal neuron HT22 cells, and ZIP9 knockdown or overexpression inhibited or further enhanced these effects. Using the ERK1/2 specific inhibitor SCH772984 and eIF4E specific inhibitor eFT508, we found that DHT activated ERK1/2 through ZIP9, resulting in eIF4E phosphorylation, thus promoting PSD95 protein expression in HT22 cells. Finally, we found that ZIP9 mediated the effects of DHT on the expression of synaptic proteins PSD95, drebrin, SYP, and dendritic spine density in the hippocampus of APP/PS1 mice through the ERK1/2-eIF4E pathway and affected learning and memory. This study demonstrated that androgen affected learning and memory in mice through ZIP9, providing new experimental evidence for improvement in learning and memory in Alzheimer's disease with androgen supplementation.

The role of cyclins in the development and progression of prostate cancer

The role of cyclins in hormone-dependent neoplasms is crucial in the development of the disease that is resistant to first-line therapy, as the example of breast cancer shows. However, in prostate cancer, cyclins are studied to a lesser extent. There are some well-described molecular pathways, including cyclins A1 and D1 signaling, however the role of other cyclins, e.g., D2, D3, E, and H, still requires further investigation. Recent studies indicate that cyclins regulate various cellular processes, not only the cell cycle. Furthermore, they remain in cross-talk with many other signaling pathways, e.g., MAPK/ERK, PI3K/Akt, and Notch. The androgen signaling axis, which is pivotal in prostate cancer progression, interferes with cyclin pathways at many levels. This article summarizes current knowledge on the influence of cyclins on prostate cancer progression by describing interactions between the androgen receptor and cyclins, as well as mechanisms underlying the development of resistance to currently used therapies.

BNIP3 mediates the different adaptive responses of fibroblast-like synovial cells to hypoxia in patients with osteoarthritis and rheumatoid arthritis

Background

Hypoxia is one of the important characteristics of synovial microenvironment in rheumatoid arthritis (RA), and plays an important role in synovial hyperplasia. In terms of cell survival, fibroblast-like synovial cells (FLSs) are relatively affected by hypoxia. In contrast, fibroblast-like synovial cells from patients with RA (RA-FLSs) are particularly resistant to hypoxia-induced cell death. The purpose of this study was to evaluate whether fibroblast-like synovial cells in patients with osteoarthritis (OA-FLSs) and RA-FLSs have the same adaptation to hypoxia.

Methods

CCK-8, flow cytometry and BrdU were used to detect the proliferation of OA-FLSs and RA-FLSs under different oxygen concentrations. Apoptosis was detected by AV/PI, TUNEL and Western blot, mitophagy was observed by electron microscope, laser confocal microscope and Western blot, the state of mitochondria was detected by ROS and mitochondrial membrane potential by flow cytometry, BNIP3 and HIF-1α were detected by Western blot and RT-qPCR. The silencing of BNIP3 was achieved by stealth RNA system technology.

Results

After hypoxia, the survival rate of OA-FLSs decreased, while the proliferation activity of RA-FLSs further increased. Hypoxia induced an increase in apoptosis and inhibition of mitophagy in OA-FLSs, but not in RA-FLSs. Hypoxia led to a more lasting adaptive response. RA-FLSs displayed a more significant increase in the expression of genes transcriptionally regulated by HIF-1α. Interestingly, they showed higher BNIP3 expression than OA-FLSs, and showed stronger mitophagy and proliferation activities. BNIP3 siRNA experiment confirmed the potential role of BNIP3 in the survival of RA-FLSs. Inhibition of BNIP3 resulted in the decrease of cell proliferation, mitophagy and the increase of apoptosis.

Conclusion

In summary, RA-FLSs maintained intracellular redox balance through mitophagy to promote cell survival under hypoxia. The mitophagy of OA-FLSs was too little to maintain the redox balance of mitochondria, resulting in apoptosis. The difference of mitophagy between OA-FLSs and RA-FLSs under hypoxia is mediated by the level of BNIP3 expression.

Human Coronary Plaque T Cells Are Clonal and Cross-React to Virus and Self

BACKGROUND

Coronary artery disease is an incurable, life-threatening disease that was once considered primarily a disorder of lipid deposition. Coronary artery disease is now also characterized by chronic inflammation' notable for the buildup of atherosclerotic plaques containing immune cells in various states of activation and differentiation. Understanding how these immune cells contribute to disease progression may lead to the development of novel therapeutic strategies.

METHODS

We used single-cell technology and in vitro assays to interrogate the immune microenvironment of human coronary atherosclerotic plaque at different stages of maturity.

RESULTS

In addition to macrophages, we found a high proportion of αβ T cells in the coronary plaques. Most of these T cells lack high expression of CCR7 and L-selectin, indicating that they are primarily antigen-experienced memory cells. Notably, nearly one-third of these cells express the HLA-DRA surface marker, signifying activation through their TCRs (T-cell receptors). Consistent with this, TCR repertoire analysis confirmed the presence of activated αβ T cells (CD4<CD8), exhibiting clonal expansion of specific TCRs. Interestingly, we found that these plaque T cells had TCRs specific for influenza, coronavirus, and other viral epitopes, which share sequence homologies to proteins found on smooth muscle cells and endothelial cells, suggesting potential autoimmune-mediated T-cell activation in the absence of active infection. To better understand the potential function of these activated plaque T cells, we then interrogated their transcriptome at the single-cell level. Of the 3 T-cell phenotypic clusters with the highest expression of the activation marker HLA-DRA, 2 clusters expressed a proinflammatory and cytolytic signature characteristic of CD8 cells, while the other expressed AREG (amphiregulin), which promotes smooth muscle cell proliferation and fibrosis, and, thus, contributes to plaque progression.

CONCLUSIONS

Taken together, these findings demonstrate that plaque T cells are clonally expanded potentially by antigen engagement, are potentially reactive to self-epitopes, and may interact with smooth muscle cells and macrophages in the plaque microenvironment.