AGEs/RAGE Promote Osteogenic Differentiation in Rat Bone Marrow-Derived Endothelial Progenitor Cells via MAPK Signaling

Abstract

Systemic vascular impairment is the most common complication of diabetes. Advanced glycation end products (AGEs) can exacerbate diabetes-related vascular damage by affecting the intima and media through a variety of mechanisms. In the study, we demonstrated that AGEs and their membrane receptor RAGE could induce the differentiation of EPCs into osteoblasts under certain circumstances, thereby promoting accelerated atherosclerosis. Differentiation into osteoblasts was confirmed by positive staining for DiI-acetylated fluorescently labeled low-density lipoprotein and FITC-conjugated Ulex europaeus agglutinin. During differentiation, expression of receptor for AGE (RAGE) was significantly upregulated. This upregulation was attenuated by transfection with RAGE-targeting small interfering (si)RNA. siRNA-mediated knockdown of RAGE expression significantly inhibited the upregulation of AGE-induced calcification-related proteins, such as runt-related transcription factor 2 (RUNX2) and osteoprotegerin (OPG). Additional experiments showed that AGE induction of EPCs significantly induced ERK, p38MAPK, and JNK activation. The AGE-induced upregulation of osteoblast proteins (RUNX2 and OPG) was suppressed by treatment with a p38MAPK inhibitor (SB203580) or JNK inhibitor (SP600125), but not by treatment with an ERK inhibitor (PD98059), which indicated that AGE-induced osteoblast differentiation from EPCs may be mediated by p38MAPK and JNK signaling, but not by ERK signaling. These data suggested that AGEs may bind to RAGE on the EPC membrane to trigger differentiation into osteoblasts. The underlying mechanism appears to involve the p38MAPK and JNK1/2 pathways, but not the ERK1/2 pathway.

Microarray meta-analysis reveals IL6 and p38β/MAPK11 as potential targets of hsa-miR-124 in endothelial progenitor cells: Implications for stent re-endothelization in diabetic patients

“…AGE interacts with RAGE to produce reactive oxygen species that activates nuclear factor kappa-B (NF-kB) and numerous proinflammatory genes of cytokines such as tumor necrosis factor-α (TNF-α), interleukins as IL6, and adhesion molecules ( 47 ). In an animal model, AGE-RAGE induced osteoblast differentiation of EPCs, mediated by p38, MAPK, and JNK signaling, promoting accelerated atherosclerosis ( 48 ). Enrichment of PI3K-AKT and AGE-RAGE signaling pathway for DEGs detected in meta-analysis reinforce the biological significance of our findings.…”

Effects of advanced glycation end products (AGEs) on the differentiation potential of primary stem cells: a systematic review

“…Wang et al . [ 48 ] showed that AGEs might bind to RAGE on the membrane of endothelial cells, thereby leading to an increase in differentiation toward osteogenesis.…”

“…Wang et al . [ 48 ] showed that AGEs/RAGE promotes osteogenic differentiation of rat bone marrow EPCs through the MAPK signaling pathway. Mitogen-activated protein kinases (MAPK) signaling pathway, a group of mitogen-activated protein kinases that extracellular stimuli can activate, is an important carrier protein that transmits stimuli on the cell surface to the nucleus, including three kinases, including p38 mitogen-activated protein kinases (p38 MAPK), extracellular regulated protein kinases1/2 (ERK1/2), and c-Jun amino-terminal kinase (JNK), which are important components of intracellular signaling pathway transduction involved in a series of cell activities such as regulating cell proliferation, apoptosis, differentiation, and survival as well as functional synchronization between cells [ 117 ].…”

A narrative review of diabetic bone disease: Characteristics, pathogenesis, and treatment

“…Hyperglycemia is the most apparent clinical manifestation in diabetes mellitus, and excess free sugars in the body adversely affect many tissues and cells. High levels of extracellular free sugars have a direct inhibitory effect on the cellular activity of, both, osteoblasts and osteocytes ( 54 , 55 ). Osteoblasts exposed to high glucose levels exhibit reduced proliferation capacity, slow extracellular matrix synthesis, and subsequently slow maturation and mineralization.…”