Effects of estrogen receptor modulators on cytoskeletal proteins in the central nervous system

Osteoporosis treatment: current drugs and future developments

Osteoporosis is a common systemic metabolic disease characterized by a decrease in bone density and bone mass, destruction of bone tissue microstructure, and increased bone fragility leading to fracture susceptibility. Pharmacological treatment of osteoporosis is the focus of current research, and anti-osteoporosis drugs usually play a role in inhibiting bone resorption, promoting bone formation, and having a dual role. However, most of the drugs have the disadvantages of single target and high toxic and side effects. There are many types of traditional Chinese medicines (TCM), from a wide range of sources and mostly plants. Herbal plants have unique advantages in regulating the relationship between osteoporosis and the immune system, acupuncture therapy has significant therapeutic effects in combination with medicine for osteoporosis. The target cells and specific molecular mechanisms of TCM in preventing and treating osteoporosis have not been fully elucidated. At present, there is a lack of comprehensive understanding of the pathological mechanism of the disease. Therefore, a better understanding of the pathological signaling pathways and key molecules involved in the pathogenesis of osteoporosis is crucial for the design of therapeutic targets and drug development. In this paper, we review the development and current status of anti-osteoporosis drugs currently in clinical application and under development to provide relevant basis and reference for drug prevention and treatment of osteoporosis, with the aim of promoting pharmacological research and new drug development.

Discovering biomarkers for hormone-dependent tumors: in silico study on signaling pathways implicated in cell cycle and cytoskeleton regulation

Malignancies dependent on hormone homeostasis include breast, ovary, cervical, prostate, testis and uterine tumors. Hormones are involved in signal transduction which orchestrate processes, such as apoptosis, proliferation, cell cycle or cytoskeleton organization. Currently, there is a need for novel biomarkers which would help to diagnose cancers efficiently. In this study, the genes implicated in signaling that is important in hormone-sensitive carcinogenesis were investigated regarding their prognostic significance. Data of seven cancer cohorts were collected from FireBrowse. 54 gene sets implicated in specific pathways were browsed through MSig database. Profiling was assessed via Monocle3, while gene ontology through PANTHER. For confirmation, correlation analysis was performed using WGCNA. Protein-protein networks were visualized via Cytoscape and impact of genes on survival, as well as cell cycle or cytoskeleton-related prognostic signatures, was tested. Several differences in expression profile were identified, some of them allowed to distinguish histology. Functional annotation revealed that various regulation of cell cycle, adhesion, migration, apoptosis and angiogenesis underlie these differences. Clinical traits, such as histological type or cancer staging, were found during evaluation of module-trait relationships. Of modules, the TopHubs (COL6A3, TNR, GTF2A1, NKX3-1) interacted directly with, e.g., PDGFB, ITGA10, SP1 or AKT3. Among TopHubs and interacting proteins, many showed an impact on hazard ratio and affected the cell cycle or cytoskeleton-related prognostic signatures, e.g., COL1A1 or PDGFB. In conclusion, this study laid the foundation for further hormone-sensitive carcinogenesis research through identification of genes which prove that crosstalk between cell cycle and cytoskeleton exists, opening avenues for future therapeutic strategies.

The Role of 17β-Estrogen in Escherichia coli Adhesion on Human Vaginal Epithelial Cells via FAK Phosphorylation

Estrogen, the predominant sex hormone, has been found to be related to the occurrence of vaginal infectious diseases. However, its role in the occurrence and development of bacterial vaginitis caused by Escherichia coli is still unclear. The objective of this study was to investigate the role of 17β-estrogen in E. coli adhesion on human vaginal epithelial cells. The vaginal epithelial cell line VK2/E6E7 was used to study the molecular events induced by estrogen between E. coli and cells. An adhesion study was performed to evaluate the involvement of the estrogen-dependent focal adhesion kinase (FAK) activation with cell adhesion. The phosphorylation status of FAK and estrogen receptor α (ERα) upon estrogen challenge was assessed by Western blotting. Specific inhibitors for ERα were used to validate the involvement of ERα-FAK signaling cascade. The results showed that, following stimulation with 1,000 nM estrogen for 48 h, transient activation of ERα and FAK was observed, as was an increased average number of E. coli cells adhering to vaginal epithelial cells. In addition, estrogen-induced activation of ERα and FAK was inhibited by the specific inhibitor of ERα, especially when the inhibitor reached a 10 μM concentration and acted for 1 h, and a decrease in the number of adherent E. coli cells was observed simultaneously. However, this inhibitory effect diminished as the concentration of estrogen increased. In conclusion, FAK and ERα signaling cascades were associated with the increasing E. coli adherence to vaginal epithelial cells, which was promoted by a certain concentration of estrogen.

Bisphenol-A exposure induced neurotoxicity and associated with synapse and cytoskeleton in Neuro-2a cells

Bisphenol A (BPA) is an environmental chemical that induces neurotoxic effects for human. Synaptophysin (SYP) and drebrin (Dbn) proteins are involved in regulating synaptic morphology. The stability of the cytoskeleton in nerve cells in the brain is regulated by Tau and MAP2. This study aimed to determine the toxicity of BPA to Neuro-2a cells by investigating the synaptic and cytoskeletal damage induced in these cells by 24 h of exposure to 0 (MEM), 50, 100, 150, or 200 μM BPA or DMSO. MTT and LDH assays showed that the death rates of Neuro-2a cells increased, as the BPA concentration increased. Ultrastructural assays revealed that cells underwent nucleolar swelling as well as nuclear membrane and partial mitochondrial dissolution or condensation, following BPA exposure. Morphological analysis further revealed that compared with the cells in the control group, the cells in the BPA-treated groups shrank, became rounded, and exhibited a reduced number of synapses. BPA also significantly decreased the relative protein and mRNA expression levels of Dbn, MAP2 and Tau (P < .01), but increased the relative protein and mRNA expression levels of SYP (P < .01). These results indicated that BPA suppressed the development and proliferation of Neuro-2a cells by disrupting cellular and synaptic integrity and inflicting cytoskeleton injury.

The Role of 17β-Estrogen in Candida albicans Adhesion on Human Vaginal Epithelial Cells via FAK Phosphorylation

PURPOSES

To investigate the role of 17β-estrogen in Candida albicans (C. albicans) adhesion on human vaginal epithelial cells in vulvovaginal candidiasis (VVC).

METHODS

The vaginal epithelial cell line, VK2/E6E7, was used to study the estrogen-induced molecular events between C. albicans and cells. An adhesion study was performed to evaluate the involvement of the estrogen-dependent focal adhesion kinase (FAK) activation in cell adhesion. The phosphorylation status of FAK and estrogen receptor α (ERα) upon estrogen challenge was assessed by western blotting. Specific inhibitors for ERα were used to validate the involvement of ERα-FAK signaling cascade.

RESULTS

A transient activation of ERα and FAK was observed following the stimulation with 1000 nM estrogen for 48 h, as well as the increased average number of C. albicans adhering to each vaginal epithelial cell. Estrogen-induced activation of ERa and FAK was inhibited by the specific inhibitor of ERα, especially when the inhibitor reached a 10 μM concentration and allowed to act for 12 h. Simultaneously, a decrease in the number of adherent C. albicans was observed. However, this inhibitory effect diminished as the concentration of estrogen increased.

CONCLUSION

FAK and ERα signaling cascades were involved in the early interaction between the vaginal epithelial cells and C. albicans, which appeared to be linked with the enhanced cell adhesion leading to VVC and promoted by a certain concentration of estrogen.

Raloxifene alleviates amyloid-β-induced cytotoxicity in HT22 neuronal cells via inhibiting oligomeric and fibrillar species formation

Raloxifene, a selective estrogen receptor modulator, displays benefits for Alzheimer's disease (AD) prevention in postmenopausal women as hormonal changes during menopause have the potential to influence AD pathogenesis, but the underlying mechanism of its neuroprotection is not entirely clear. In this study, the effects of raloxifene on amyloid-β (Aβ) amyloidogenesis were evaluated. The results demonstrated that raloxifene inhibits Aβ₄₂ aggregation and destabilizes preformed Aβ₄₂ fibrils through directly interacting with the N-terminus and middle domains of Aβ₄₂ peptides. Consequently, raloxifene not only reduces direct toxicity of Aβ₄₂ in HT22 neuronal cells, but also suppresses expressions of tumor necrosis factor-α and transforming growth factor-β induced by Aβ₄₂ peptides, and then alleviates microglia-mediated indirect toxicity of Aβ₄₂ to HT22 neuronal cells. Our results suggested an alternative possible explanation for the neuroprotective activity of raloxifene in AD prevention.

Lifetime exposure to estrogen and progressive supranuclear palsy: Environmental and Genetic PSP study

BACKGROUND

Studies suggesting a protective effect of estrogen in neurodegenerative diseases prompted us to investigate this relationship in progressive supranuclear palsy (PSP).

METHODS

This case-control study evaluated the self-reported reproductive characteristics and estrogen of 150 women with PSP and 150 age-matched female controls who participated in the Environmental Genetic-PSP study. Conditional logistic regression models were generated to examine associations of PSP with estrogen.

RESULTS

There was no association between years of estrogen exposure duration and PSP. There was a suggestion of an inverse association between composite estrogen score and PSP that did not reach statistical significance (P = .06). Any exposure to estrogen replacement therapy halved the risk of PSP (odds ratio = 0.52; 95% confidence interval = 0.30-0.92; P = .03). Among PSP cases, earlier age at menarche was associated with better performance on Hoehn and Yahr stage (β = -0.60; SE = 0.26; P = .02) and Unified Parkinson's Disease Rating Scale II score (β = -5.19; SE = 2.48; P = .04) at clinical examination.

CONCLUSIONS

This case-control study suggests a protective role of lifetime estrogen exposure in PSP. Future studies will be needed to confirm this association. © 2018 International Parkinson and Movement Disorder Society.