Search bioRxiv⌕ Search

bioRxiv · 10.1101/2022.02.01.478701

CLEC5A and TLR2 are critical in SARS-CoV-2-induced NET formation and lung inflammation

Abstract

Coronavirus-induced disease 19 (COVID-19) infects more than three hundred and sixty million patients worldwide, and people with severe symptoms frequently die of acute respiratory distress syndrome (ARDS). Autopsy demonstrates the presence of thrombosis and microangiopathy in the small vessels and capillaries. Recent studies indicated that excessive neutrophil extracellular traps (NETs) contributed to immunothrombosis, thereby leading to extensive intravascular coagulopathy and multiple organ dysfunction. Thus, understanding the mechanism of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-induced NET formation would be helpful to reduce thrombosis and prevent ARDS. It has been shown that sera from individuals with COVID-19 triggered NET release in vitro, and spleen tyrosine kinase (Syk) inhibitor R406 inhibited NETosis caused by COVID-19 plasma. However, the serum components responsible for NET formation are still unknown. In this study, we found that virus-free extracellular vesicles (EVs) from COVID-19 patients (COVID-19 EVs) induced robust NET formation via Syk-coupled C-type lectin member 5A (CLEC5A). Blockade of CLEC5A inhibited COVID-19 EVs-induced NETosis, and simultaneous blockade of CLEC5A and TLR2 further suppressed SARS-CoV-2-induced NETosis in vitro. Moreover, thromboinflammation and lung fibrosis were attenuated dramatically in clec5a-/-/tlr2-/- mice. These results suggest that COVID-19 EVs play critical roles in SARS-CoV-2-induced immunothrombosis, and blockade of CLEC5A and TLR2 is a promising strategy to inhibit SARS-CoV-2-induced intravascular coagulopathy and reduce the risk of ARDS in COVID-19 patients.

Source connections

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Sung, P.-S., Yang, S.-P., Peng, Y.-C., Sun, C.-P., Tao, M.-H., Hsieh, S.-L.. 2022-02-02. CLEC5A and TLR2 are critical in SARS-CoV-2-induced NET formation and lung inflammation. https://doi.org/10.1101/2022.02.01.478701

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

Proliferation and mutation as humoral immune response

The affinity maturation process, through which antibodies acquire relatively high affinity for an invading pathogen, involves complex mechanisms whose relative importance is not yet fully understood. This study proposes an analytical model of this process, to investigate the main factors governing proliferation and mutation and assess their respective roles. The model suggests that the immune system should not be expected to follow a single, rigid evolutionary pattern, as a wide range of proliferation and mutation strategies can yield nearly optimal outcomes. Keywords: Antibody, antigen, affinity, B-cell, mutation, proliferation

immunology↗

Proteome-wide discovery of novel diagnostic antigens for coccidioidomycosis

Coccidioidomycosis, commonly called Valley Fever (VF), caused by Coccidioides spp., is an understudied fungal disease that accounts for a substantial fraction of pneumonias in endemic areas. Diagnosis remains challenging because the mainstay of diagnosis is serology, and current assays have modest sensitivity in early infection. Discovery of new antigens could improve serologic detection early in disease. Here, we use PepSeq, a DNA-programmable serology platform, to represent the complete proteome of Coccidioides within a library of 244,000 DNA-barcoded peptides. By profiling antibody reactivity at the protein and epitope levels in VF patients, naturally infected pigtail macaques, and healthy controls, we identify numerous previously-unrecognized antigens and epitopes, including some shared between humans and macaque responses. When translated into a pooled peptide ELISA, we show that a subset of identified antigens can discriminate VF cases from controls in an independent cohort with high accuracy (AUC = 0.91). These findings establish high-dimensional peptide serology as a scalable approach for fungal antigen discovery and identify new targets for improved VF diagnosis.

immunology↗

Establishing an ex vivo platform for molecular profiling of skin structural cells using frozen human skin biopsies

Skin structural cells, including keratinocytes, melanocytes, endothelial cells, and fibroblasts, play critical roles in the development of chronic inflammatory skin disease. Inflammatory stimuli induce transcriptional reprogramming and epigenetic changes in skin structural cells, which contribute to disease pathogenesis. Although two-dimensional (2D) and three-dimensional (3D) skin culture models have been widely used to investigate inflammatory responses in skin structural cells, ex vivo systems that maintain skin structure and cellular composition remain limited. To address this gap, we explored using frozen skin biopsies as an experimental platform to study the responses of skin structural cells to inflammatory stimuli. Using a simple air-liquid interface culture method on permeable Transwell inserts, we showed that viable skin structural cells that retain cell-type-specific transcriptional profiles can be recovered from frozen skin biopsies after prolonged in vitro culture. Stimulation with IFN-{gamma} induced robust transcriptional and chromatin accessibility changes that were largely resolved after stimulus removal, with transcriptional responses to secondary stimulation comparable to the primary stimulation. Treatment of cultured skin biopsies with histone-modifying enzyme inhibitors effectively altered global histone modification levels, but did not substantially affect the transcriptional resolution of IFN-{gamma}-induced responses. Collectively, these findings establish cryopreserved human skin biopsies as a scalable ex vivo platform that enables mechanistic studies of inflammatory responses of multiple populations of skin structural cells.

immunology↗