The RANKL/RANK/OPG Signaling Pathway Mediates Medial Arterial Calcification in Diabetic Charcot Neuroarthropathy

Abstract

OBJECTIVEThe receptor activator of nuclear factor-κB (RANK), RANK ligand (RANKL), and osteoprotegerin (OPG) signaling pathway (RANKL/RANK/OPG signaling) is implicated in the osteolysis associated with diabetic Charcot neuroarthropathy (CN); however, the links with medial arterial calcification (MAC) seen in people with CN are unclear. This study aimed to investigate the role of RANKL/OPG in MAC in patients with CN.RESEARCH DESIGN AND METHODSEnzyme-linked immunosorbent assay and Bio-plex multiarray technology were used to quantify a range of cytokines, including RANKL and OPG in sera from 10 patients with diabetes, 12 patients with CN, and 5 healthy volunteers. Human tibial artery segments were immunohistochemically stained with Alizarin red and human RANKL antibody. Human vascular smooth muscle cells (VSMCs) were also explanted from arterial segments for in vitro studies.RESULTSWe demonstrate colocalization and upregulation of RANKL expression in areas displaying MAC. Systemic levels of RANKL, OPG, and inflammatory cytokines (interleukin-8, granulocyte colony–stimulating factor) were elevated in those with CN compared with diabetic patients and healthy control subjects. Human VSMCs cultured in CN serum showed accelerated osteoblastic differentiation (alkaline phosphatase activity) and mineralization (alizarin red staining) compared with cells treated with diabetic or control serum (P < 0.05). Coincubation with OPG, the decoy receptor for RANKL, attenuated osteogenic differentiation of VSMCs and was independent of a high calcium-phosphate milieu. The accelerated mineralization induced by RANKL and CN serum correlated with nuclear translocation of nuclear factor-κB, a process abrogated by OPG.CONCLUSIONSOur data provide direct evidence that RANKL/RANK/OPG signaling is modulated in patients with CN and plays a role in vascular calcification. This study highlights this pathway as a potential target for intervention.

Receptor Activator of NF-κB Ligand Promotes Proliferation of a Putative Mammary Stem Cell Unique to the Lactating Epithelium

“…RANKL-induced calcification has also been demonstrated in other human tissue hierarchies, where calcification occurs in the less differentiated endothelial compartment of the tissue. In vascular tissue, RANKL activation of the ERK pathway is required for insulin-induced osteoblastic differentiation and subsequent calcification, and in aortic tissue, RANKL-induced calcification is inhibited by estrogen [42][43][44]. This supports our observation in the PMEC and implies RANKL may be involved in breast epithelial calcifications.…”

Data Mining for Identifying Novel Associations and Temporal Relationships with Charcot Foot

“…This proinflammatory cytokine activity has also been described as a part of the etiology model [24, 31]. In our study, we found that coronary artery disease (CAD) demonstrated an odds ratio of 18.6 with Charcot foot.…”

No influence of OPG and its ligands, RANKL and TRAIL, on proliferation and regulation of the calcification process in primary human vascular smooth muscle cells

“…Two studies have shown that OPG's ligand TRAIL induces proliferation of VSMCs (Kavurma et al, 2008;Secchiero et al, 2004). Three recent studies showed that the addition of OPG inhibit calcification of VSMCs in vitro (Di Bartolo et al, 2011;Ndip et al, 2011;Schoppet et al, 2011). Moreover, it has been reported that RANKL (Panizo et al, 2009) and TRAIL (Chasseraud et al, 2011) stimulates calcification of VSMCs.…”