Tail suspension delays ectopic ossification in proteoglycan‑induced ankylosing spondylitis in mice via miR‑103/DKK1

Abstract

Ankylosing spondylitis (AS), characterized by inflammatory lesions and osteophyte formation, is a common immune rheumatic disease affecting the sacroiliac and axial joints. A high-intensity mechanical load is known to accelerate the heterotopic ossification associated with enthesitis in AS. Thus, the present study explored whether decreased mechanical load could delay the heterotopic ossification in AS. First, 24-week-old female BALB/c mice were induced with proteoglycan (PG) to establish an AS model. The AS-induced pathological and bone morphological changes of the sacroiliac joint were confirmed by hematoxylin and eosin staining and microCT analysis, respectively. Subsequently, the mice were treated with interventions of different mechanical loads. Using reverse transcription-quantitative PCR, it was revealed that expression levels of the osteogenesis-related genes bone morphogenetic protein-2, runt-related transcription factor 2 and osteocalcin were significantly reduced in sacroiliac bone tissue after intervention with a reduced mechanical load. The level of mechanosensory microRNA (miR)-103 increased in response to reduced mechanical loads. Consistently, in groups with reduced mechanical load, proteins with mechanical functions, including ρ-associated coiled-coil-containing protein kinase 1 (ROCK1), phosphorylated (p)-Erk1/2 and β-catenin, were reduced compared with the PG control. A dual-luciferase assay verified that miR-103 binds to the 3'-untranslated region end of Rock1 mRNA, thus negatively regulating the activity of Rock1 and affecting pathological ossification during AS. However, immunohistochemical staining indicated that the expression of dickkopf Wnt signaling pathway inhibitor 1, an inhibitor of the Wnt/β-catenin pathway, was increased in sacroiliac tissues. The results indicated that tail suspension decreased the mechanical load, thus reducing the bone formation in AS mice. Furthermore, tail suspension could inhibit the activation of mechanical kinase ROCK1 and p-Erk1/2 in the MAPK signaling pathway by upregulating miR-103, thereby inhibiting the classical osteogenesis-related Wnt/β-catenin pathway in AS. In summary, the present study uncovered the ameliorative effect of suspension on AS and its therapeutic potential for AS.

Exploration of the combined role of immune checkpoints and immune cells in the diagnosis and treatment of ankylosing spondylitis: a preliminary study immune checkpoints in ankylosing spondylitis

“…GSK269962A is a selective inhibitor of ROCK1 (Rho-associated protein kinase 1) [53]. In a mouse model of AS, the inhibition of ROCK1 and the activation of p-Erk1/2 in the MAPK signaling pathway were found to suppress the osteoblast-related classical Wnt/β-catenin pathway, thereby alleviating abnormal ossification in AS [54].…”

Monocyte subpopulations display disease-specific miRNA signatures depending on the subform of Spondyloarthropathy

“…Interestingly, in a mouse model of axSpA, miR-103 levels were found elevated in animals subjected to reduced mechanical loads. Moreover, the increase of miR-103 expression led to upregulation of the potent osteogenesis inhibitor - Dkk-1 - and hence, reduced new bone formation/bone density in SpA mice ( 48 ). Whether similar, miR-103-driven mechanism operates also in human axSpA, remains to be verified.…”