Expression of FSHR in chondrocytes and the effect of FSH on chondrocytes

High-fat diet aggravates the severity of the in vitro posttraumatic osteoarthritis model through macrophagic FBW7

Osteoarthritis (OA) is a prevalent and distressing chronic degenerative joint disorder characterized by damaged articular cartilage and inflamed joints. Among risk factors, obesity has emerged as the second-leading contributor to OA after age. Obesity is believed to play a key role in the development and progression of OA. This study aimed to investigate the role and underlying mechanisms of high-fat diet (HFD)-induced obesity in the development of OA. Our findings revealed that HFD could aggravate the destabilization of the medial meniscus (DMM)-induced damage in the mouse model of obesity. Similar results were observed when macrophages obtained from HFD-fed mice were cocultured with cartilage and subsequently stimulated with interleukin-1β (IL-1β). Mechanistically, we observed a decrease in the expression of intraarticular macrophagic FBW7, which was implicated in the aggravation of OA in the HFD-fed animal. Furthermore, by modulating the immune status of macrophages, we found that reversing the macrophagic expression of FBW7 in these cells can alleviate the chondrocyte damage. In conclusion, this study provides novel insights into the pathological mechanisms underlying HFD-related OA development by identifying the role of FBW7 in synovial macrophages. These findings open up new avenues for research and therapeutic interventions targeting HFD-related OA.

Uncovering the "riddle of femininity" in osteoarthritis: a systematic review and meta-analysis of menopausal animal models and mathematical modeling of estrogen treatment

OBJECTIVE

Post-menopausal women are disproportionately affected by osteoarthritis (OA). As such, the purpose of this study was to (1) summarize the state-of-the-science aimed at understanding the effects of menopause on OA in animal models and (2) investigate how dosage and timing of initiation of estrogen treatment affect cartilage degeneration.

DESIGN

A systematic review identified articles studying menopausal effects on cartilage in preclinical models. A meta-analysis was performed using overlapping cartilage outcomes in conjunction with a rigor and reproducibility analysis. Ordinary differential equation models were used to determine if a relationship exists between cartilage degeneration and the timing of initiation or dosage of estrogen treatment.

RESULTS

Thirty-eight manuscripts were eligible for inclusion. The most common menopause model used was ovariectomy (92%), and most animals were young at the time of menopause induction (86%). Most studies did not report inclusion criteria, animal monitoring, protocol registration, or data accessibility. Cartilage outcomes were worse in post-menopausal animals compared to age-matched, non-menopausal animals, as evidenced by cartilage histological scoring [0.75, 1.72], cartilage thickness [-4.96, -0.96], type II collagen [-4.87, -0.56], and c-terminal cross-linked telopeptide of type II collagen (CTX-II) [2.43, 5.79] (95% CI of Effect Size (+greater in menopause, -greater in non-menopause)). Moreover, modeling suggests that cartilage health may be improved with early initiation and higher doses of estrogen treatment.

CONCLUSIONS

To improve translatability, animal models that consider aging and natural menopause should be utilized, and more attention to rigor and reproducibility is needed. Timing of initiation and dosage may be important factors modulating therapeutic effects of estrogen on cartilage.

LINC00707 knockdown inhibits IL-1β-induced apoptosis and extracellular matrix degradation of osteoarthritis chondrocytes by the miR-330-5p/FSHR axis

BACKGROUND

Osteoarthritis (OA) is a severe disabling condition that causes major health problems. The roles of lncRNAs in regulating OA progression have been increasingly researched. Based on previously published microarray analysis, LINC00707 is upregulated in OA. This research was done to uncover the function of LINC00707 in IL-1β-induced chondrocyte injury and its possible mechanisms.

METHODS

LINC00707, miR-330-5p, and FSHR expression in OA cartilage tissues were assessed by RT-qPCR. Primary chondrocytes were isolated from OA tissues and treated with IL-1β to establish an in vitro OA model. Under the indicated treatment, chondrocyte apoptosis, senescence, ECM degradation, and inflammation were determined using flow cytometry, TUNEL, SA-β-Gal staining, and ELISA experiments, respectively. Interactions between gene were evaluated using Ago2 RIP and luciferase reporter assays.

RESULTS

LINC00707 and FSHR were elevated, and miR-330-5p was reduced in cartilage tissues of OA patients and in IL-1β-treated primary chondrocytes. Silencing LINC00707 hampered chondrocytes apoptosis, senescence, ECM degradation, and inflammation. LINC00707 acted as a ceRNA to regulate FSHR through controlling miR-330-5p availability. Additionally, both miR-330-5p depletion and FSHR overexpression diminished the effects of silencing LINC00707 in OA progression.

CONCLUSION

Silencing LINC00707 mitigates chondrocyte injury in osteoarthritis via sponging miR-330-5p and inhibiting FSHR.

G Protein-Coupled Receptors in Osteoarthritis

Osteoarthritis (OA) is the most common chronic joint disease characterized, for which there are no available therapies being able to modify the progression of OA and prevent long-term disability. Critical roles of G-protein coupled receptors (GPCRs) have been established in OA cartilage degeneration, subchondral bone sclerosis and chronic pain. In this review, we describe the pathophysiological processes targeted by GPCRs in OA, along with related preclinical model and/or clinical trial data. We review examples of GPCRs which may offer attractive therapeutic strategies for OA, including receptors for cannabinoids, hormones, prostaglandins, fatty acids, adenosines, chemokines, and discuss the main challenges for developing these therapies.

FSH modulated cartilage ECM metabolism by targeting the PKA/CREB/SOX9 pathway

INTRODUCTION

Osteoarthritis (OA) is a common joint disease characterized by articular cartilage degeneration. The prevalence of OA is higher among women than men, and this prevalence is closely related to menopause. The classic view assumes that the underlying mechanism of postmenopausal OA is attributed to declining estrogen levels. Although follicle-stimulating hormone (FSH) levels become elevated in parallel, the effects of FSH on OA have been poorly explored. The present study aimed to study the effect of FSH on cartilage metabolism.

METHODS

Chondrocyte-like ATDC5 cells were treated with recombinant FSH protein. Then the cell viability was measured using cell counting kit-8 assay. Expressions of crucial factors involved in the extracellular matrix (ECM) metabolic and PKA-CREB-SOX9 pathway were analyzed by western blot, RT-qPCR, and immunofluorescence staining. Intracellular cAMP levels were assessed by ELISA assay. Experimental OA in mice was induced by destabilization of the medial meniscus (DMM) surgery. Adeno-associated virus expressing shRNA against FSHR (AAV-shFSHR) was intra-articular (IA) injected into the OA model animals to specifically knock down FHSR in cartilage. Histological staining and OARSI scores were used to assess the efficacy of AAV-shFSHR injections.

RESULTS

We found that FSH down-regulated the expression of ECM-related proteins in chondrocyte-like ATDC5 cells. The underlying mechanism is probably associated with regulating PKA/CREB/SOX9 pathway. Besides, blocking FSH signaling via shRNA-mediated downregulation of FSHR in joint tissues effectively delayed the development of posttraumatic OA in mice.

CONCLUSIONS

Our results collectively indicated that FSH plays an essential role in the pathogenesis of OA and acts as a crucial mediator.

Follicle-stimulating hormone worsens osteoarthritis by causing inflammation and chondrocyte dedifferentiation

Previous studies have found follicle‐stimulating hormone (FSH) receptors on chondrocytes (cartilage cells), but the mechanism of FSH action on chondrocytes is not clear. The purpose of this experiment is to study whether FSH affects chondrocytes and how it causes changes in these cells. Our results show that osteoarthritis became worse after FSH injection in the knee joint of mice. After the stimulation of chondrocytes by FSH, a total of 664 up‐regulated genes, such as Col12a1 and Col1a1, and 644 down‐regulated genes, such as MGP, were screened by transcriptomics. A subset of extracellular matrix (ECM)‐related genes and pathways underwent Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, and the downregulation of MGP, the upregulation of EGR1 and Col1a1, and the increase of IL‐6 were verified. It was also observed that FSH can inhibit the cAMP/PKA and MKK4/JNK signaling pathway. In conclusion, we demonstrated that FSH can increase cartilage inflammatory response and promote chondrocyte dedifferentiation by inhibiting the cAMP/PKA and MKK4/JNK signaling pathways.

High Circulating Follicle-Stimulating Hormone Level Is a Potential Risk Factor for Renal Dysfunction in Post-Menopausal Women

OBJECTIVE

Menopause contributes to renal dysfunction in women, which is generally attributed to estrogen withdrawal. In addition to decreased estrogen level, serum follicle-stimulating hormone (FSH) level increases after menopause. This study investigated the association between high circulating FSH level and renal function in post-menopausal women.

METHODS

This observational cross-sectional study included 624 pre-menopausal, 121 peri-menopausal, and 2540 post-menopausal women. The levels of female sex hormones were examined by chemiluminescence and indices of renal function were measured using a clinical chemistry analyzer. The post-menopausal women were grouped into quartiles according to serum FSH levels.

RESULTS

Renal function progressively declined from pre-menopause to peri-menopause to post-menopause, which was accompanied by increasing serum FSH level. In post-menopausal women, serum creatinine level increased with increasing FSH quartile, which was accompanied by a decrease in estimated glomerular filtration rate (eGFR) (p for trend <0.001); moreover, the prevalence of declined eGFR (<90 ml/min/1.73 m²) and chronic kidney disease (CKD; eGFR <60 ml/min/1.73 m²) increased (p for trend <0.001). Even after adjusting for confounders, the odds ratios (ORs) of declined eGFR and CKD increased with increasing FSH quartiles in post-menopausal women. The ORs of declined eGFR (OR=2.19, 95% confidence interval [CI]: 1.63-2.92) and CKD (OR=10.09, 95% CI: 2.28-44.65) in the highest FSH quartile were approximately 2- and 10-fold higher, respectively, than in the lowest FSH quartile (p<0.05). After stratifying post-menopausal women by median age (61 years), the OR for declined eGFR for each FSH quartile in the older group was higher than that for the corresponding FSH quartile in the younger group.

CONCLUSIONS

A high circulating FSH level is an independent risk factor for renal dysfunction in women after menopause. Additionally, aging may aggravate the association of high FSH levels with reduced renal function in post-menopausal women.

Role of FSH and FSH receptor on HUVECs migration

Follicle-stimulating hormone (FSH) is a pituitary glycoprotein that regulates follicle maturation through its binding to follicle-stimulating hormone receptor (FSHR). Endothelial cells express FSHR, but its exact role in endothelial cells remains unclear. Here we show that FSHR expression was detectable in human umbilical vein endothelial cells (HUVECs). FSH stimulation promoted HUVECs migration but not proliferation. Because FSHR is a GPCR, FSH treatment triggers the activation of cAMP-PKA signaling pathways, and the JAK-STAT, PI3K-AKT, and JNK-MAPK pathways. RNAi of FSHR dramatically attenuated the activation effect of FSH on HUVECs migration, as well as the related signaling pathways. Treatment of FSH in HUVECs also transcriptionally upregulated the expression of VAV3 and LAMA2, suppression either of VAV3 or LAMA2 by RNAi attenuated the FSH's effect on HUVECs migration. All of these results indicated a functional role of FSH in the regulation of endothelial cells.

High follicle-stimulating hormone levels accelerate cartilage damage of knee osteoarthritis in postmenopausal women through the PI3K/AKT/NF-κB pathway

Osteoarthritis is the main cause of pain and disability in the elderly, with the most commonly affected joint being the knee. The prevalence of knee osteoarthritis (KOA) is significantly increased in postmenopausal women, although the mechanisms underlying KOA remain unclear. The present study aimed to investigate the association between follicle‐stimulating hormone (FSH) and postmenopausal women with KOA aged between 50 and > 70 years, as well as explore its underlying molecular mechanisms. Here, we report that the 50–60 years age group had the highest level of serum FSH. Compared to the low FSH group (< 40 mIU·mL⁻¹) in the same age group, the high FSH group (> 40 mIU·mL⁻¹) showed more severe cartilage damage. Furthermore, phosphorylated (p)‐phosphoinositide 3‐kinase (PI3K)/PI3K, p‐AKT/AKT and p‐nuclear factor kappa B (NF‐κB)/NF‐κB levels were significantly higher in the high FSH group compared to the low FSH group. Immunofluorescence experiments showed that FSH stimulation promoted the translocation of NF‐κB p65 into the nucleus, and decreased type II collagen and aggrecan in ATDC5 cells. Moreover, we used western blotting in ATDC5 cells to demonstrate that FSH decreased type II collagen and increased p‐PI3K/PI3K, p‐AKT/AKT, p‐NF‐κB/NF‐κB and p‐IKB/IKB in a concentration‐dependent manner. Our results suggest that increased FSH levels are associated with KOA for postmenopausal women aged 50–60 years and that high FSH levels might damage the cartilage tissues through the PI3K/AKT/NF‐κB pathway.

Human Ovarian Granulosa Cells Isolated during an IVF Procedure Exhibit Differential Expression of Genes Regulating Cell Division and Mitotic Spindle Formation

Granulosa cells (GCs) are a population of somatic cells whose role after ovulation is progesterone production. GCs were collected from patients undergoing controlled ovarian stimulation during an in vitro fertilization procedure, and they were maintained for 1, 7, 15, and 30 days of in vitro primary culture before collection for further gene expression analysis. A study of genes involved in the biological processes of interest was carried out using expression microarrays. To validate the obtained results, Reverse Transcription quantitative Polymerase Chain Reaction (RT-qPCR) was performed. The direction of changes in the expression of the selected genes was confirmed in most of the examples. Six ontological groups ("cell cycle arrest", "cell cycle process", "mitotic spindle organization", "mitotic spindle assembly checkpoint", "mitotic spindle assembly", and "mitotic spindle checkpoint") were analyzed in this study. The results of the microarrays obtained by us allowed us to identify two groups of genes whose expressions were the most upregulated (FAM64A, ANLN, TOP2A, CTGF, CEP55, BIRC5, PRC1, DLGAP5, GAS6, and NDRG1) and the most downregulated (EREG, PID1, INHA, RHOU, CXCL8, SEPT6, EPGN, RDX, WNT5A, and EZH2) during the culture. The cellular ultrastructure showed the presence of structures characteristic of mitotic cell division: a centrosome surrounded by a pericentric matrix, a microtubule system, and a mitotic spindle connected to chromosomes. The main goal of the study was to identify the genes involved in mitotic division and to identify the cellular ultrastructure of GCs in a long-term in vitro culture. All of the genes in these groups were subjected to downstream analysis, and their function and relation to the ovarian environment are discussed. The obtained results suggest that long-term in vitro cultivation of GCs may lead to their differentiation toward another cell type, including cells with cancer-like characteristics.

Vascular Endothelial FSH Receptor, a Target of Interest for Cancer Therapy

Improved molecular understanding of tumor microenvironment has resulted in the identification of various cancer cell targets for diagnostic and therapeutic interventions, including the receptor for the FSH, a glycoprotein hormone responsible for growth, maturation, and function of human reproductive system. The expression and localization of the FSH receptor (FSHR)-protein were associated with the tumor epithelial cells and/or with the peripheral tumor blood vessels. The available evidence indicates that in ovarian cancer, prostate cancer, and breast cancer, the tumor epithelial FSHR promotes proliferation, migration, and invasion of cancer cells. The vascular endothelial FSHR, detected in 11 types of solid tumors and 11 types of sarcomas, is involved in receptor-mediated transendothelial transport of FSH, tumor angiogenesis, and vascular remodeling. In contrast to intratumor vessels, which are abnormal and disorganized, the FSHR-positive blood microvessels are arranged in a hierarchical pattern: arterioles-capillaries-venules. The FSHR-positive blood vessels make connections between the intratumor vessels and the general blood circulation of patients. In this mini-review, I summarize these studies and discuss the rationale for developing a strategy for cancer therapy based on FSHR expressed on the luminal endothelial cell surface of blood vessels located in the peritumoral area rather than endothelial markers expressed in the core of tumors. Because FSHR is a common marker of peritumoral vessels, therapeutic agents coupled to anti-FSHR humanized antibodies should in principle be applicable to a wide range of tumor types.