scholarly journals TMPRSS2 and furin are both essential for proteolytic activation and spread of SARS-CoV-2 in human airway epithelial cells and provide promising drug targets

Author(s):  
Dorothea Bestle ◽  
Miriam Ruth Heindl ◽  
Hannah Limburg ◽  
Thuy Van Lam van ◽  
Oliver Pilgram ◽  
...  

AbstractIn December 2019, a novel coronavirus named SARS-CoV-2 first reported in Wuhan, China, emerged and rapidly spread to numerous other countries globally, causing the current pandemic. SARS-CoV-2 causes acute infection of the respiratory tract (COVID-19) that can result in severe disease and lethality. Currently, there is no approved antiviral drug for treating COVID-19 patients and there is an urgent need for specific antiviral therapies and vaccines.In order for SARS-CoV-2 to enter cells, its surface glycoprotein spike (S) must be cleaved at two different sites by host cell proteases, which therefore represent potential drug targets. In the present study we investigated which host cell proteases activate the SARS-CoV-2 S protein in Calu-3 human airway epithelial cells. We show that S can be cleaved by both the proprotein convertase furin at the S1/S2 site and the transmembrane serine protease 2 (TMPRSS2) at the S2’ site. We demonstrate that TMPRSS2 is essential for activation of SARS-CoV-2 S in Calu-3 cells through antisense-mediated knockdown of TMPRSS2 expression. Further, we show that SARS-CoV-2 replication can be efficiently inhibited by two synthetic inhibitors of TMPRSS2 and also by the broad range serine protease inhibitor aprotinin. Additionally, SARS-CoV-2 replication was also strongly inhibited by the synthetic furin inhibitor MI-1851. Combining various TMPRSS2 inhibitors with MI-1851 produced more potent antiviral activity against SARS-CoV-2 than an equimolar amount of any single serine protease inhibitor. In contrast, inhibition of endosomal cathepsins by E64d did not affect virus replication.Our data demonstrate that both TMPRSS2 and furin are essential for SARS-CoV-2 activation in human airway cells and are promising drug targets for the treatment of COVID-19 either by targeting one of these proteases alone or by a combination of furin and TMPRSS2 inhibitors. Therefore, this approach has a high therapeutic potential for treatment of COVID-19.

2010 ◽  
Vol 78 (12) ◽  
pp. 5314-5323 ◽  
Author(s):  
Xiuping Liu ◽  
Lee M. Wetzler ◽  
Laura Oliveira Nascimento ◽  
Paola Massari

ABSTRACT The human airway epithelium is constantly exposed to microbial products from colonizing organisms. Regulation of Toll-like receptor (TLR) expression and specific interactions with bacterial ligands is thought to mitigate exacerbation of inflammatory processes induced by the commensal flora in these cells. The genus Neisseria comprises pathogenic and commensal organisms that colonize the human nasopharynx. Neisseria lactamica is not associated with disease, but N. meningitidis occasionally invades the host, causing meningococcal disease and septicemia. Upon colonization of the airway epithelium, specific host cell receptors interact with numerous Neisseria components, including the PorB porin, at the immediate bacterial-host cell interface. This major outer membrane protein is expressed by all Neisseria strains, regardless of pathogenicity, but its amino acid sequence varies among strains, particularly in the surface-exposed regions. The interaction of Neisseria PorB with TLR2 is essential for driving TLR2/TLR1-dependent cellular responses and is thought to occur via the porin's surface-exposed loop regions. Our studies show that N. lactamica PorB is a TLR2 ligand but its binding specificity for TLR2 is different from that of meningococcal PorB. Furthermore, N. lactamica PorB is a poor inducer of proinflammatory mediators and of TLR2 expression in human airway epithelial cells. These effects are reproduced by whole N. lactamica organisms. Since the responsiveness of human airway epithelial cells to colonizing bacteria is in part regulated via TLR2 expression and signaling, commensal organisms such as N. lactamica would benefit from expressing a product that induces low TLR2-dependent local inflammation, likely delaying or avoiding clearance by the host.


2015 ◽  
Vol 48 (3) ◽  
pp. 177-188 ◽  
Author(s):  
Claudia Guevara ◽  
Chengxian Zhang ◽  
Jennifer A. Gaddy ◽  
Junaid Iqbal ◽  
Julio Guerra ◽  
...  

1999 ◽  
Vol 277 (3) ◽  
pp. L465-L471 ◽  
Author(s):  
Alessandro Celi ◽  
Silvana Cianchetti ◽  
Stefano Petruzzelli ◽  
Stefano Carnevali ◽  
Filomena Baliva ◽  
...  

Intercellular adhesion molecule-1 (ICAM-1) is the only inducible adhesion receptor for neutrophils identified in bronchial epithelial cells. We stimulated human airway epithelial cells with various agonists to evaluate whether ICAM-1-independent adhesion mechanisms could be elicited. Phorbol 12-myristate 13-acetate (PMA) stimulation of cells of the alveolar cell line A549 caused a rapid, significant increase in neutrophil adhesion from 11 ± 3 to 49 ± 7% (SE). A significant increase from 17 ± 4 to 39 ± 6% was also observed for neutrophil adhesion to PMA-stimulated human bronchial epithelial cells in primary culture. Although ICAM-1 expression was upregulated by PMA at late time points, it was not affected at 10 min when neutrophil adhesion was already clearly enhanced. Antibodies to ICAM-1 had no effect on neutrophil adhesion. In contrast, antibodies to the leukocyte integrin β-chain CD18 totally inhibited the adhesion of neutrophils to PMA-stimulated epithelial cells. These results demonstrate that PMA stimulation of human airway epithelial cells causes an increase in neutrophil adhesion that is not dependent on ICAM-1 upregulation.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nadzeya Marozkina ◽  
Laura Smith ◽  
Yi Zhao ◽  
Joe Zein ◽  
James F. Chmiel ◽  
...  

AbstractEndothelial hemoglobin (Hb)α regulates endothelial nitric oxide synthase (eNOS) biochemistry. We hypothesized that Hb could also be expressed and biochemically active in the ciliated human airway epithelium. Primary human airway epithelial cells, cultured at air–liquid interface (ALI), were obtained by clinical airway brushings or from explanted lungs. Human airway Hb mRNA data were from publically available databases; or from RT-PCR. Hb proteins were identified by immunoprecipitation, immunoblot, immunohistochemistry, immunofluorescence and liquid chromatography- mass spectrometry. Viral vectors were used to alter Hbβ expression. Heme and nitrogen oxides were measured colorimetrically. Hb mRNA was expressed in human ciliated epithelial cells. Heme proteins (Hbα, β, and δ) were detected in ALI cultures by several methods. Higher levels of airway epithelial Hbβ gene expression were associated with lower FEV1 in asthma. Both Hbβ knockdown and overexpression affected cell morphology. Hbβ and eNOS were apically colocalized. Binding heme with CO decreased extracellular accumulation of nitrogen oxides. Human airway epithelial cells express Hb. Higher levels of Hbβ gene expression were associated with airflow obstruction. Hbβ and eNOS were colocalized in ciliated cells, and heme affected oxidation of the NOS product. Epithelial Hb expression may be relevant to human airways diseases.


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