Effect of metformin on ossification and inflammation of fibroblasts in ankylosing spondylitis: An in vitro study

Abstract

Ankylosing spondylitis (AS) is an autoimmune disease characterized by fibroblasts ossification. However, effective drug therapy for AS is lacking. As an antidiabetic drug, metformin has demonstrated an antiosteogenic effect on osteoblasts in vitro. And it is also a kind of specific agonists for adenosine 5′-monophosphate activated protein kinase (AMPK), which is blocked in the process of AS. Given the role in antiosteogenesis and AMPK activating, metformin was investigated of its effect on fibroblasts harvested from capsular ligament of patients with femoral neck fracture and AS. Osteogenic specific makers (Alp, Bglap, Runx2, Bmp2, and Col1) in fibroblasts administered with metformin (20 μg/mL) were detected by ALP staining, alizarin red staining, qPCR, and Western blotting after 7 and 14 days of culture. Inflammation genes (il1-β and il6) and pathway (Pi3k, Akt, and Ampk) associated markers were also evaluated. Our results showed that osteogenic specific markers were greatly downregulated and ossification was effectively inhibited in AS fibroblasts after addition of metformin. Levels of inflammation markers were also decreased by metformin. Thus, metformin exerts potent effect on suppression of ossification and inflammation in AS fibroblasts via the activation of Pi3k/Akt and AMPK pathways, which may be developed as a potential agent for treatment of AS. K E Y W O R D Sankylosing spondylitis, fibroblasts, metformin, ossification Xiong Qin, Tongmeng Jiang, and Sijia Liu contributed equally to this work.

Metformin and Autoimmunity: A “New Deal” of an Old Drug

“…In cardiac fibroblasts, metformin treatment has been shown to inhibit fibrosis and collagen synthesis via the TGF-β/Smad3 signaling pathway ( 120 ) and to impair the differentiation into myofibroblasts ( 121 ). A similar effect was observed in other cellular models, including nasal polyp-derived fibroblasts ( 122 ), renal fibroblasts ( 123 ), hepatic stellate cells ( 124 ), and in fibroblasts harvested from capsular ligaments of ankylosing spondylitis patients ( 125 ). In lungs, metformin attenuates gefitinib-induced exacerbation of pulmonary fibrosis by inhibiting the TGF-β/SMAD2/3 signaling pathway ( 126 ).…”

Differentially expressed mRNAs, lncRNAs, and miRNAs with associated co-expression and ceRNA networks in ankylosing spondylitis

“…Previous studies have demonstrated the involvement of BMP signaling pathway in new bone formation in AS [ 34 ]. The PI3K–Akt signaling pathway and its downstream targets were reported to be critical regulators of bone formation and involved in the pathogenesis of AS [ 35 ]. The JAK–STAT signaling pathway has also been suggested to regulate Th17 cells in AS [ 36 ].…”

Identification of lncRNAs associated with the pathogenesis of ankylosing spondylitis

“…These lncRNAs were also associated with signaling pathways including the TNF, PI3K-Akt, Rap1, Hippo, and HIF-1 pathways, which are primarily involved in in ammatory immune regulation and osteogenic differentiation. In some prior studies, the PI3K-Akt signaling pathway has been suggested to promote broblastic ossi cation and in ammation in the context of AS [24]. Some of the identi ed pathways, including the Rap1, Hippo, and HIF-1 pathways, have not previously been studied in the context of AS, and thus warrant future investigation.…”