Repurposing the multiple sclerosis drug Siponimod for osteoporosis treatment.

Osteoporosis is the most common bone disorder, in which an imbalance between osteoclastic bone resorption and osteoblastic bone formation disrupts bone homeostasis. Osteoporosis management using anti-osteoclastic agents is a promising strategy; however, this remains an unmet need. Sphingosine-1-phosphate (S1P) and its receptors (S1PRs) are essential for maintaining bone homeostasis. Here, we identified that Siponimod, a Food and Drug Administration-approved S1PR antagonist for the treatment of multiple sclerosis, shows promising therapeutic effects against osteoporosis by inhibiting osteoclast formation and function. We found that Siponimod inhibited osteoclast formation in a dose-dependent manner without causing cytotoxicity. Podosome belt staining and bone resorption assays indicated that Siponimod treatment impaired osteoclast function. Western blot and qPCR assays demonstrated that Siponimod suppressed the expression of osteoclast-specific markers, including C-Fos, Nftac1, and Ctsk. Mechanistically, we validated that Siponimod downregulated receptor activator of nuclear factor kappa B ligand (RANKL)-induced Mitogen-activated protein kinases (MAPKs) and nuclear factor kappa B (NF-κB) signaling pathways during osteoclastogenesis. Moreover, in a preclinical mouse model, Siponimod prevented ovariectomy-induced bone loss by suppressing osteoclast activity in vivo. Collectively, these results suggest that Siponimod could serve as an alternative therapeutic agent for the treatment of osteoporosis.

Obacunone targets macrophage migration inhibitory factor (MIF) to impede osteoclastogenesis and alleviate ovariectomy-induced bone loss.

INTRODUCTION: Osteoporosis is the most common bone disorder where the hyperactive osteoclasts represent the leading role during the pathogenesis. Targeting hyperactive osteoclasts is currently the primary therapeutic strategy. However, concerns about the long-term efficacy and side effects of current frontline treatments persist. Alternative therapeutic agents are still needed. OBJECTIVES: Obacunone (OB) is a small molecule with a broad spectrum of biological activities, particularly antioxidant and anti-inflammatory effects. This study aims to examine OB's therapeutic potential on osteoporosis and explore the rudimentary mechanisms. METHODS: Osteoclast formation and osteoclastic resorption assays were carried out to examine OB's inhibitory effects in vitro, followed by the in-vivo studies of OB's therapeutic effects on ovariectomy-induced osteoporotic preclinical model. To further study the underlying mechanisms, mRNA sequencing and analysis were used to investigate the changes of downstream pathways. The molecular targets of OB were predicted, and in-silico docking analysis was performed. Ligand-target binding was verified by surface plasmon resonance (SPR) assay and Western Blotting assay. RESULTS: The results indicated that OB suppressed the formation of osteoclast and its resorptive function in vitro. Mechanistically, OB interacts with macrophage migration inhibitory factor (MIF) which attenuates receptor activator of nuclear factor kappa B (NF-κB) ligand (RANKL)-induced signaling pathways, including reactive oxygen species (ROS), NF-κB pathway, and mitogen-activated protein kinases (MAPKs). These effects eventually caused the diminished expression level of the master transcriptional factor of osteoclastogenesis, nuclear factor of activated T cells 1 (NFATc1), and its downstream osteoclast-specific proteins. Furthermore, our data revealed that OB alleviated estrogen deficiency-induced osteoporosis by targeting MIF and thus inhibiting hyperactive osteoclasts in vivo. CONCLUSION: These results together implicated that OB may represent as a therapeutic candidate for bone disorders caused by osteoclasts, such as osteoporosis.

Changes in thyroid function during controlled ovarian hyperstimulation (COH) and its impact on assisted reproduction technology (ART) outcomes: a systematic review and meta-analysis.

BACKGROUND: To investigate the thyroid function changes during controlled ovarian hyperstimulation (COH) and ascertain its impact on reproductive outcomes. METHODS: We conducted meta-analysis in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A comprehensive literature search was performed to identify studies reported changes in thyroid parameters during COH. We analyzed thyroid-stimulating hormone (TSH) levels, free thyroxin (fT4) levels, changes in estrogens (E2), thyroxine-binding globulin (TBG), relative risks (RRs) of clinical pregnancy rate (CPR), live birth rate (LBR), and mean difference (MD) of TSH increment between the miscarriage group and ongoing pregnancy group. RESULTS: This meta-analysis included fifteen individual studies (n = 1665 subjects). At the end of COH, the mean TSH (2.53 mIU/L; 95% CI, 2.19 to 2.88; I2 = 92.9%) exceeded the upper limit (2.5 mIU/L) and remained above the threshold until one month following embryo transfer (ET). Thyroxin decreased from baseline to the end of COH (-0.18 ng/l; 95% CI, -0.35 to 0.00; I2 = 92.2%). The CPR and LBR of patients with TSH exceeding the cutoff after COH were significantly lower than those of patients with TSH below the threshold (CPR: RR, 0.62; 95% CI, 0.47 to 0.82; I2 = 0.0% and LBR: RR, 0.64; 95% CI, 0.44 to 0.92; I2 = 0.0%). The MD of the increment in TSH levels between the miscarriage and ongoing pregnancy groups was 0.40 mIU/L (95% CI, 0.15 to 0.65; I2 = 0.0%). CONCLUSIONS: This meta-analysis shows that TSH increases and fT4 decreases during COH. COH-induced thyroid disorder impairs reproductive outcomes.

Prevotella histicola Mitigated Estrogen Deficiency-Induced Depression via Gut Microbiota-Dependent Modulation of Inflammation in Ovariectomized Mice.

BACKGROUND: Estrogen deficiency-induced depression is closely associated with an imbalance in intestinal microbiota and inflammation. Prevotella histicola (P. histicola), an emerging probiotic, apparently improves inflammatory responses. This study aims to verify the antidepressant-like effects of P. histicola and clarify its potential mechanisms. METHODS: Mice were treated with P. histicola and cohousing after ovariectomy (OVX). The changes in depression-like behaviors among mice were examined by behavioral tasks, and alterations in the microbiota were detected through 16S rRNA sequencing. Changes in neuronal injury, protein synthesis, inflammatory factors, intestinal permeability, and nerve proliferation were observed by H&E, Nissl staining, qRT-PCR, western blotting, and immunofluorescence. RESULTS: P. histicola significantly reduces depression-like behaviors and neuronal damage induced by estrogen deficiency. Additionally, P. histicola significantly increases the abundance of intestinal flora, especially Lactobacillus and Akkermansia. Meanwhile, the cohoused mice also had a better emotional state and neutral structure compared with OVX mice. P. histicola was also found to upregulate tight junction proteins ZO-1, occludin, claudin-1, and MUC2 in the ileum and colon and reduce the levels of inflammatory factors VCAM, MCP-1, IL-6, IL-8, and TNF-α, mainly in the ileum, colon, and decrease the expression of COX-2, TLR4, Myd88, JNK, MCP-1, IL-6, IL-8, and TNF-α in the hippocampus. Moreover, significant downregulation of apoptosis (caspase-3 and caspase-8) and upregulation of neurotrophic factors (BDNF and Ki-67) were observed after P. histicola treatment. CONCLUSION: Our data show that P. histicola significantly mitigates depression of OVX mice through improvement in intestinal microbiota to repair intestinal leakage and inhibit central inflammation to promote the expression of BDNF for hippocampal neurogenesis. P. histicola may be therapeutically beneficial for PMD.

CD23 expression on switched memory B cells bridges T-B cell interaction in allergic rhinitis.

BACKGROUND: The contribution of B-cell subsets and T-B cell interaction to the pathogenesis of allergic rhinitis (AR) and mechanisms of allergen immunotherapy (AIT) remain poorly understood. This study aimed to outline circulating B-cell signature, the underlying mechanism, and its association with clinical response to AIT in patients with AR. METHODS: IgD/CD27 and CD24/CD38 core gating systems were used to determine frequencies and phenotypes of B cells. Correlations between B cells, T cells, antigen-specific IgE, and disease severity in AR patients were investigated. Switched memory B cells were co-cultured with type 2 follicular helper T (Tfh2) cells and follicular regulatory T (Tfr) cells. Associations between B-cell subsets and clinical benefits of AIT were analyzed. RESULTS: Frequencies and absolute numbers of circulating memory B cells were increased in AR patients. CD23 expression on CD19+ CD20+ CD27+ IgD- switched memory B cells was significantly enhanced and positively correlated with antigen-specific IgE levels, symptom scores, and Tfh2/Tfr cell ratio in AR patients. Compared with those from healthy controls, Tfh2 cells from AR patients had a greater capacity to induce CD23 expression on switched memory B cells via IL-4, which was unable to be sufficiently suppressed by AR-associated Tfr cells with defective IL-10 expression. CD23 expression on switched memory B cells was downregulated after 12-month AIT, which positively associated with disease remission in AR patients. CONCLUSION: T-B cell interaction, bridged by CD23 expression particularly on switched memory B cells, may be involved in the disease pathogenesis and mechanism of AIT in patients with AR.