Intracellular calcium ions facilitate dengue virus entry into endothelial cells and compromise endothelial barrier integrity

Meng-hooi Shu; Sing-sin Sam; Shih-keng Loong; Boon-teong Teoh; Sazaly Abubakar; Pooi-fong Wong; Sing-sin Sam; Shih-keng Loong; Boon-teong Teoh; Sazaly Abubakar

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Intracellular calcium ions facilitate dengue virus entry into endothelial cells and compromise endothelial barrier integrity

Author: Meng-Hooi SHU ¹ ; Sing-Sin SAM ¹ ; Shih-Keng LOONG ¹ ; Boon-Teong TEOH ¹ ; Sazaly ABUBAKAR ¹ ; Pooi-Fong WONG ² ; Sing-Sin SAM ³ ; Shih-Keng LOONG ³ ; Boon-Teong TEOH ³ ; Sazaly ABUBAKAR ³
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1. Tropical Infectious Diseases Research and Education Centre (TIDREC), Universiti Malaya
2. Department of Pharmacology, Faculty of Medicine, Universiti Malaya
3. Tropical Infectious Diseases Research and Education Centre (TIDREC), World Hlth. Org. Collaborating Ctr. for Arbovirus Ref. and Res. (Dengue and Severe Dengue) MAA-12, Universiti Malaya
Publication Type:Journal Article
Keywords: Calcium signalling; Dengue virus; Endothelial cells; Endothelium permeability; Intracellular calcium
From: Asian Pacific Journal of Tropical Medicine 2021;14(11):505-516
CountryChina
Language:Chinese
Abstract: Objective: To investigate the involvement of Ca2+ in dengue virus (DENV)-infected human umbilical vein endothelial cells (HUVECs) and the disruption of endothelial integrity. Methods: HUVECs were infected with DENV-2 in the presence of intracellular Ca2+ or endoplasmic reticulum Ca2+ chelators. Virus infectivity was measured by focus-forming assay and quantitative RT-PCR. Intracellular Ca2+ was measured using Fluo-4-AM dye. VE-cadherin and focal adhesion kinase (FAK) expressions were investigated by immunofluorescence and immunoblotting assays, respectively. Results: DENV infection increased intracellular cytosolic Ca2+ levels and caused disassembly of the adherens junction protein, VEcadherin as evidenced by decreased VE-cadherin expression at the periphery of DENV-2 infected HUVECs. Depletion of intracellular Ca2+ stores, particularly those of the endoplasmic reticulum Ca2+, significantly decreased DENV yield in HUVECs. Decreased virus yield following the depletion of intracellular Ca2+ was caused by the inhibition of viral entry into HUVECs and not the inhibition of viral binding or attachment. DENV-2 infection also resulted in Ca2+- dependent activation of FAK. Conclusions: Intracellular Ca2+ is required for the early phases of DENV infection in endothelial cells. Increased cytosolic Ca2+ levels in endothelial cells during DENV infection activated FAK, disrupted adherens junctions and compromised barrier integrity. Thus, Ca2+ plays an important role in DENV infection in endothelial cells.