Calcium dobesilate reduces VEGF signaling by interfering with heparan sulfate binding site and protects from vascular complications in diabetic mice

Abstract

Inhibiting vascular endothelial growth factor (VEGF) is a therapeutic option in diabetic microangiopathy. However, VEGF is needed at physiological concentrations to maintain glomerular integrity; complete VEGF blockade has deleterious effects on glomerular structure and function. Anti-VEGF therapy in diabetes raises the challenge of reducing VEGF-induced pathology without accelerating endothelial cell injury. Heparan sulfate (HS) act as a coreceptor for VEGF. Calcium dobesilate (CaD) is a small molecule with vasoprotective properties that has been used for the treatment of diabetic microangiopathy. Preliminary evidence suggests that CaD interferes with HS binding sites of fibroblast growth factor. We therefore tested the hypotheses that (1) CaD inhibits VEGF signaling in endothelial cells, (2) that this effect is mediated via interference between CaD and HS, and (3) that CaD ameliorates diabetic nephropathy in a streptozotocin-induced diabetic mouse model by VEGF inhibition. We found that CaD significantly inhibited VEGF 165 -induced endothelial cell migration, proliferation, and permeability. CaD significantly inhibited VEGF 165 -induced phosphorylation of VEGFR-2 and suppressed the activity of VEGFR-2 mediated signaling cascades. The effects of CaD in vitro were abrogated by heparin, suggesting the involvement of heparin-like domain in the interaction with CaD. In addition, VEGF 121 , an isoform which does not bind to heparin, was not inhibited by CaD. Using the proximity ligation approach, we detected inhibition of interaction in situ between HS and VEGF and between VEGF and VEGFR-2. Moreover, CaD reduced VEGF signaling in mice diabetic kidneys and ameliorated diabetic nephropathy and neuropathy, suggesting CaD as a VEGF inhibitor without the negative effects of complete VEGF blockade and therefore could be useful as a strategy in treating diabetic nephropathy.

Calcium Dobesilate Modulates PKCδ-NADPH Oxidase- MAPK-NF-κB Signaling Pathway to Reduce CD14, TLR4, and MMP9 Expression during Monocyte-to-Macrophage Differentiation: Potential Therapeutic Implications for Atherosclerosis

“…However, its mechanism(s) in mediating these events has remained unknown. Consequently, we hypothesized that CaD might reduce monocyte-to-macrophage differentiation, one specific hallmark of inflammation (and atherosclerosis) that involves signaling via PKCδ and MAPK, previously shown as mediators of CaD activity in a diabetes model [ 14 , 37 ].…”

“…Moreover, CD14 and TLR4 play a vital role in initiating sterile inflammation related to atherosclerosis [ 2 , 3 , 28 ]. Therefore, the effect of CaD to decrease CD14 and TLR4 expression could offer one mechanism to explain why CaD inhibits NF-κB and suppresses the release of downstream NF-κB activation products—TNFα, IL-1β, IL-6, and MCP-1 in animal models of sepsis and diabetic nephropathy and retinopathy [ 11 , 13 , 14 , 32 ]. Indeed, in this study, CaD demonstrated potent anti-inflammatory effects by suppressing TNFα, IL-1β, and MCP-1 levels in PMA, LPS, and high glucose-treated THP-1 cells, which CaD significantly suppressed, suggesting a broad therapeutic spectrum potential of CaD [ 11 , 12 , 13 , 14 , 32 , 53 ].…”

“…One limitation of this study is that we cannot rule out that CaD downregulates the PKCδ pathway via VEGF signaling since CaD is also a VEGF signaling inhibitor in endothelial cells [ 14 ]. ROS scavengers can also inhibit angiogenic factor production due to a direct effect on monocytes/macrophages [ 85 ], and antioxidants, such as phenolic compounds, vitamins C and E, likewise inhibit VEGF-VEGFR signaling [ 86 , 87 ].…”

“…Calcium dobesilate (CaD) is a vasoactive and angioprotective drug having a unique and multi-target mode of action in several experimental studies and different animal models of diabetic microvascular complications. CaD reduces oxidative stress, inflammation, and vascular complications via diverse molecular targets [ 11 , 12 , 13 , 14 ]. At present, CaD is prescribed to treat microvascular damage-related diseases—diabetic retinopathy and diabetic nephropathy; however, most studies have focused only on endothelial cells.…”

Comparative study between calcium dobesilate and proteolytic enzymes in treatment of simple ovarian cyst

“…CaD binds to the heparin-binding domain of FGF-1, thus reducing FGF-1 activity. CaD could act as a new VEGF antagonist without adverse side effects [3].…”