bims-noxint Biomed News
on NADPH oxidases in tumorigenesis
Issue of 2021–09–05
two papers selected by
Laia Caja Puigsubira, Uppsala University
  1. Inhibition of NADPH oxidase blocks NETosis and reduces thrombosis in heparin-induced thrombocytopenia.
  2. Diabetes Promotes Retinal Vascular Endothelial Cell Injury by Inducing CCN1 Expression.
  1. Blood Adv. 2021 Sep 03. pii: bloodadvances.2020003093. [Epub ahead of print]
    Inhibition of NADPH oxidase blocks NETosis and reduces thrombosis in heparin-induced thrombocytopenia.
    Halina Leung, Jose Perdomo, Zohra Ahmadi, Feng Yan, Steven E McKenzie, Beng H Chong.
      Heparin-induced thrombocytopenia (HIT) is associated with severe and potentially lethal thrombotic complications. NETosis was recently shown to be an important driver of thrombosis in HIT. We investigated the role of reactive oxygen species (ROS) and NADPH oxidase 2 (NOX2) and their contributions to thrombus development in HIT. We showed that neutrophil activation by HIT immune complexes induced ROS-dependent NETosis. Analysis of thrombi formed in a microfluidics system showed ROS production in both platelets and neutrophils, and abundant NETs and ROS distributed throughout the clot. Neutrophil-targeted ROS inhibition was sufficient to block HIT-induced NETosis and thrombosis using human blood. Inhibition of NOX2 with diphenyleneiodonium chloride or GSK2795039 abrogated HIT-induced thrombi in vivo using FcγRIIa+/hPF4+ transgenic mice. Thrombocytopenia in mice remained unaffected by ROS inhibition. Increased ROS production in activated neutrophils were also confirmed using fresh blood from patients with active HIT. Our findings show that ROS and NOX2 play a crucial role in NETosis and thrombosis in HIT. This enhances our understanding of the processes driving thrombosis in HIT and identifies NOX2 as a potential new therapeutic target for antithrombotic treatment for HIT.
    DOI:  https://doi.org/10.1182/bloodadvances.2020003093
  2. Front Cardiovasc Med. 2021 ;8 689318
    Diabetes Promotes Retinal Vascular Endothelial Cell Injury by Inducing CCN1 Expression.
    Haicheng Li, Ting Li, Heting Wang, Xuemin He, Ying Li, Siying Wen, Rongdong Peng, Yuanpeng Nie, Yan Lu, He Yang, Yinong Ye, Guojun Shi, Yanming Chen.
      Purpose: Diabetic retinopathy (DR) is one of the most common diabetic microvascular complications. However, the pathogenesis of DR has not yet been fully elucidated. This study aimed to discover novel and key molecules involved in the pathogenesis of DR, which could potentially be targets for therapeutic DR intervention. Methods: To identify potential genes involved in the pathogenesis of DR, we analyzed the public database of neovascular membranes (NVMs) from patients with proliferative diabetic retinopathy (PDR) and healthy controls (HCs) (GSE102485, https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE102485). Further, we compared these findings by performing RNA-sequencing analysis of peripheral blood mononuclear cells (PBMC) from patients with DR, control patients with non-complicated diabetes mellitus (DMC), and HCs. To determine the critical role of candidate genes in DR, knockdown or knockout was performed in human retinal vascular endothelial cells (HRVECs). The oxidative stress pathway, as well as tight junction integrity, was analyzed. Results: Transcriptional profiles showed distinct patterns between the NVMs of patients with DR and those of the HCs. Those genes enriched in either extracellular matrix (ECM)-receptor interaction or focal adhesion pathways were considerably upregulated. Both pathways were important for maintaining the integrity of retinal vascular structure and function. Importantly, the gene encoding the matricellular protein CCN1, a key gene in cell physiology, was differentially expressed in both pathways. Knockdown of CCN1 by small interfering RNA (siRNA) or knockout of CCN1 by the CRISPR-Cas9 technique in HRVECs significantly increased the levels of VE-cadherin, reduced the level of NADPH oxidase 4 (NOX4), and inhibited the generation of reactive oxygen species (ROS). Conclusion: The present study identifies CCN1 as an important regulator in the pathogenesis of DR. Increased expression of CCN1 stimulates oxidative stress and disrupts tight junction integrity in endothelial cells by inducing NOX4. Thus, targeting the CCN1/NOX4 axis provides a therapeutic strategy for treating DR by alleviating endothelial cell injury.
    Keywords:  CCN1; NOX4 NADPH oxidase; diabetic retinopathy; oxidative stress; tight junction
    DOI:  https://doi.org/10.3389/fcvm.2021.689318
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