Histamine H1 receptor inverse agonists improve structure and pain in an osteoarthritis mouse model
Ichiro Kurakazu, Merissa Olmer, Hannah Swahn, Kevin Myers, Chelsea Kenvisay, Yukio Akasaki, Yasuharu Nakashima, Martin K. Lotz
Ichiro Kurakazu, Merissa Olmer, Hannah Swahn, Kevin Myers, Chelsea Kenvisay, Yukio Akasaki, Yasuharu Nakashima, Martin K. Lotz
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Research Article Aging Bone biology Cell biology

Histamine H1 receptor inverse agonists improve structure and pain in an osteoarthritis mouse model

Abstract

Osteoarthritis (OA) is the most common joint disease. Controlling the complex pathogenesis is challenging, thus, disease-modifying OA drugs are not available. Forkhead box O (FOXO) transcription factors contribute to cartilage homeostasis through autophagy and oxidative stress resistance. Here, we sought to discover FOXO activators and found that cyproheptadine, a histamine H1 receptor (HRH1) inverse agonist, promoted FOXO3 nuclear translocation and increased FOXO target genes while suppressing inflammation. In a murine OA model, cyproheptadine reduced structural joint tissue damage and pain behaviors. Mechanistically, the inhibition of HRH1 constitutive activity mediated the effects of cyproheptadine on calcium balance between endoplasmic reticulum (ER) and cytoplasm, and FOXO activation was part of this mechanism. The antiinflammatory effect of cyproheptadine involved the inhibition of protein kinase C/NF-κB pathway. HRH1 inhibition also suppressed osteogenesis in mesenchymal stem cells and nerve growth factor expression, which are mechanisms of osteophyte formation and pain behaviors. Moreover, cyproheptadine suppressed ER stress–induced lipogenesis by upregulating insulin-induced gene 1. Our findings suggest that HRH1 constitutive activity controls important OA-promoting mechanisms and indicate that HRH1 inverse agonists are promising drug repurposing candidates for structure and pain improvement in OA.

Authors

Ichiro Kurakazu, Merissa Olmer, Hannah Swahn, Kevin Myers, Chelsea Kenvisay, Yukio Akasaki, Yasuharu Nakashima, Martin K. Lotz

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Figure 4

Antiinflammatory effects of cyproheptadine via NF-κB pathway.

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Antiinflammatory effects of cyproheptadine via NF-κB pathway. (A) Volcan...
(A) Volcano plot of the DEGs in RNA-seq performed on human chondrocytes (n = 5) treated with IL-1β (1 ng/mL) for 6 hours. (B) Volcano plot of the DEGs in RNA-seq performed on human chondrocytes (n = 5) treated with IL-1β (1 ng/mL) for 6 hours after pretreatment with or without cyproheptadine (CYP) for 24 hours. (C) Venn diagram of the shared upregulated genes by IL-1β stimulation and the downregulated genes by CYP treatment under IL-1β stimulation. Metascape enrichment (D) and TRRUST (E) analysis using the shared genes in C. (F) GSEA showing induced “cytokine-mediated signaling pathway” in chondrocytes treated with IL-1β. (G) GSEA showing inhibited “cytokine-mediated signaling pathway” in chondrocytes treated with CYP under IL-1β stimulation. (H) Western blot analysis of total p65 and phosphorylated p65 at Ser536 (p-p65 (Ser536)) in chondrocytes (n = 4) incubated with IL-1β (1 ng/mL) for 20 minutes after pretreatment with or without CYP (30 μM) for 24 hours. (I) Immunocytochemistry of p65 in chondrocytes (n = 3) incubated with IL-1β (1 ng/mL) for 20 minutes after pretreatment with or without CYP (30 μM) for 24 hours. Scale bar: 50 μm. Data are presented as means ± SD. Statistical analysis was performed using 1-way ANOVA with the Tukey-Kramer post hoc test. **P < 0.01, ***P < 0.001, ****P < 0.0001.