Glomerular Function and Structural Integrity Depend on Hyaluronan Synthesis by Glomerular Endothelium

Abstract

Background A glycocalyx envelope consisting of proteoglycans and adhering proteins covers endothelial cells, both the luminal and abluminal surface. We previously demonstrated that short-term loss of integrity of the luminal glycocalyx layer resulted in perturbed glomerular filtration barrier function.

Loss of Endothelial Glycocalyx Hyaluronan Impairs Endothelial Stability and Adaptive Vascular Remodeling after Arterial Ischemia

“…High molecular weight HA enhances human pulmonary EC barrier function and inhibits LPS-induced pulmonary vascular leakiness [27]. Our recent study showed that endothelial specific deletion of has2 in mice leads to loss of HA incorporation in glycocalyx, causing endothelial dysfunction and vascular destabilization in multiple tissues, such as kidney, retina and heart [10]. Here, we further explored that loss of endothelial HA impaired microvascular perfusion and dysregulated angiogenesis in response to artery occlusion, which is clinically related to diabetic patients with critical limb ischemia.…”

“…14-150). Presence of introduced genes from ear pinched DNA samples is performed on all animals during breeding and for confirmation of has2 gene mutation (exon 2 deletion) after tamoxifen on Has2-cKO mice at the end of the experiment using PCR and primers, as described earlier [10]. Only Has2-cKO mice with a confirmed mutation within their has2 gene were examined further.…”

“…Slides were blocked in Serum-Free Protein Block buffer (Dako) for 1 h at room temperature. Primary Goat anti-mouse Ang1 (AF923, R&D Systems, Minneapolis, MN, USA), rabbit anti laminin (Z0097, Dako), rat anti-mouse PDGFβ (ab51876, Abcam, Cambridge, UK), HA binding peptide Neurocan-dsRed [10] (200 µg/mL), or lectin from Bandeiraea simplicifolia isolectin B4 (BS-1-TRITC, L5264, Sigma or BS-1-BIOTIN, L2140, Sigma, Zwijndrecht, the Netherlands) were incubated overnight at 4 • C in blocking buffer, followed by an appropriate secondary antibodies for 1 h at room temperature. Human diabetic muscle sections (4 µm thick) of critical limb ischemia biopsies treated as above and incubated overnight with Ncan-dsRed (200 µg/mL) and Rabbit anti-Human CD31 antibody (ab28364, Abcam) at 4 • C, followed by an appropriate secondary antibody for 1 h in blocking buffer, washed with PBS.…”

“…The endothelial glycocalyx is a negative charged gel-like structure coating the surface of endothelial cells (ECs), which is critically involved in vascular integrity and homeostasis, such as vascular 2 of 13 permeability, mechanotransduction, inflammation and coagulation [5,6]. For vascular homeostasis the selective binding capacity of growth factors and chemokines to endothelial glycocalyx is essential [7][8][9][10]. In pathological conditions, like inflammation, hyperglycemia, and atherosclerosis, the endothelial glycocalyx is degraded by enzymes such as heparanase and hyaluronidases [11][12][13].…”

Glomerular Endothelial Cells as Instigators of Glomerular Sclerotic Diseases

“…Proteoglycans with bound GAGs, of which heparan sulphate and hyaluronan constitute up to 90%, are the main contributors to the function and structure of the endothelial glycocalyx ( Reitsma et al., 2007 ; Slater et al., 2012 ; Garsen et al., 2014 ; Dane et al., 2015 ). In DN and FSGS, the endothelial glycocalyx is reduced, characterized by a loss of essential GAGs, including heparan sulphate and hyaluronan, and reduced thickness ( Nieuwdorp et al., 2006a ; Kuwabara et al., 2010 ; Satoh et al., 2010 ; van den Berg et al., 2019 ). Environmental factors, such as elevated levels of glucose, oxidative stress, or inflammatory stimuli, can modulate the endothelial glycocalyx ( Singh et al., 2011 ; Singh et al., 2013 ; Kolarova et al., 2014 ).…”