Endothelial heparan sulfate deficiency reduces inflammation and fibrosis in murine diabetic nephropathy

Abstract

Inflammation plays a vital role in the development of diabetic nephropathy, but the underlying regulatory mechanisms are only partially understood. Our previous studies demonstrated that, during acute inflammation, endothelial heparan sulfate (HS) contributes to the adhesion and transendothelial migration of leukocytes into perivascular tissues by direct interaction with l-selectin and the presentation of bound chemokines. In the current study, we aimed to assess the role of endothelial HS on chronic renal inflammation and fibrosis in a diabetic nephropathy mouse model. To reduce sulfation of HS specifically in the endothelium, we generated Ndst1f/fTie2Cre+ mice in which N-deacetylase/N-sulfotransferase-1 (Ndst1), the gene that initiates HS sulfation modifications in HS biosynthesis, was expressly ablated in endothelium. To induce diabetes, age-matched male Ndst1f/fTie2Cre− (wild type) and Ndst1f/fTie2Cre+ mice on a C57Bl/6J background were injected intraperitoneally with streptozotocin (STZ) (50 mg/kg) on five consecutive days (N = 10–11/group). Urine and plasma were collected. Four weeks after diabetes induction the animals were sacrificed and kidneys were analyzed by immunohistochemistry and qRT-PCR. Compared to healthy controls, diabetic Ndst1f/fTie2Cre− mice showed increased glomerular macrophage infiltration, mannose binding lectin complement deposition and glomerulosclerosis, whereas these pathological reactions were prevented significantly in the diabetic Ndst1f/fTie2Cre+ animals (all three p < 0.01). In addition, the expression of the podocyte damage marker desmin was significantly higher in the Ndst1f/fTie2Cre− group compared to the Ndst1f/fTie2Cre+ animals (p < 0.001), although both groups had comparable numbers of podocytes. In the cortical tubulo-interstitium, similar analyses show decreased interstitial macrophage accumulation in the diabetic Ndst1f/fTie2Cre+ animals compared to the diabetic Ndst1f/fTie2Cre− mice (p < 0.05). Diabetic Ndst1f/fTie2Cre+ animals also showed reduced interstitial fibrosis as evidenced by reduced density of αSMA-positive myofibroblasts (p < 0.01), diminished collagen III deposition (p < 0.001) and reduced mRNA expression of collagen I (p < 0.001) and fibronectin (p < 0.001). Our studies indicate a pivotal role of endothelial HS in the development of renal inflammation and fibrosis in diabetic nephropathy in mice. These results suggest that HS is a possible target for therapy in diabetic nephropathy.

Novel Insights Into the Role of Glycans in the Pathophysiology of Glomerular Endotheliosis in Preeclampsia

“…Lastly, chemokine transport through the endothelial cell layer, known as the transcytosis process, apparently depends on HS expression ( Wang et al, 2005 ). Concerning data from Talsma et al (2018) indicate a pivotal role of endothelial HS in the development of renal inflammation and fibrosis in diabetic nephropathy in mice ( Talsma et al, 2018 ). The results showed that a decrease in sulfations of endothelial HS induced an increased glomerular macrophage infiltration, mannose binding lectin complement deposition, and glomerulosclerosis ( Talsma et al, 2018 ).…”

ErHuang Formula Improves Renal Fibrosis in Diabetic Nephropathy Rats by Inhibiting CXCL6/JAK/STAT3 Signaling Pathway

“…Inflammation is considered a critical initiator in the pathophysiology of DN and several lines of evidence have shown that some cytokines and chemokines, such as nuclear factor-kB (NF-kB), interleukin-6 (IL-6), tumor necrosis factor-a (TNF-a), transforming growth factor-b (TGF-b) and Soluble C-X-C chemokine ligand (CXCLs), play a vital role in the inflammatory response (Wada and Makino, 2013;Talsma et al, 2018). In addition, fibrosis related factors matrix metalloproteinases (MMPs) and collagen are also of important factors in DN.…”

Heparan sulfate as a regulator of inflammation and immunity

“…Importantly, L‐ and P‐selectin doubly deficient mice showed no further decrease in leukocyte recruitment following heparin treatment, confirming that heparin inhibits inflammation primarily through these two selectins . Similarly, the reduced HS sulfation achieved by conditional deletion of Ndst1 from only endothelial cells and leukocytes results in reduced leukocyte recruitment in models of peritonitis, allergen‐induced airway remodeling, and diabetic and experimental glomerulonephritis. Of particular interest was the observation that chimeric WT mice with Ndst1‐null bone marrow do not show any defect in thioglycollate‐induced lymphocyte homing, whereas KO mice given WT bone marrow show the same reduction in cell infiltrate seen in the mice lacking both endothelial and leukocyte Ndst1 .…”