Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 8 de 8
Filter
2.
Sci Rep ; 12(1): 5207, 2022 03 25.
Article in English | MEDLINE | ID: covidwho-1764204

ABSTRACT

The cell surface serine protease Transmembrane Protease 2 (TMPRSS2) is required to cleave the spike protein of SARS-CoV-2 for viral entry into cells. We determined whether negatively-charged heparin enhanced TMPRSS2 inhibition by alpha-1-antitrypsin (AAT). TMPRSS2 activity was determined in HEK293T cells overexpressing TMPRSS2. We quantified infection of primary human airway epithelial cells (hAEc) with human coronavirus 229E (HCoV-229E) by immunostaining for the nucleocapsid protein and by the plaque assay. Detailed molecular modeling was undertaken with the heparin-TMPRSS2-AAT ternary complex. Enoxaparin enhanced AAT inhibition of both TMPRSS2 activity and infection of hAEc with HCoV-229E. Underlying these findings, detailed molecular modeling revealed that: (i) the reactive center loop of AAT adopts an inhibitory-competent conformation compared with the crystal structure of TMPRSS2 bound to an exogenous (nafamostat) or endogenous (HAI-2) TMPRSS2 inhibitor and (ii) negatively-charged heparin bridges adjacent electropositive patches at the TMPRSS2-AAT interface, neutralizing otherwise repulsive forces. In conclusion, enoxaparin enhances AAT inhibition of both TMPRSS2 and coronavirus infection. Such host-directed therapy is less likely to be affected by SARS-CoV-2 mutations. Furthermore, given the known anti-inflammatory activities of both AAT and heparin, this form of treatment may target both the virus and the excessive inflammatory consequences of severe COVID-19.


Subject(s)
COVID-19 , Enoxaparin , COVID-19/drug therapy , Enoxaparin/pharmacology , HEK293 Cells , Humans , SARS-CoV-2 , Serine Endopeptidases
3.
Mayo Clin Proc ; 96(3): 824-825, 2021 03.
Article in English | MEDLINE | ID: covidwho-1182629
4.
Am J Respir Crit Care Med ; 203(5): 645-646, 2021 03 01.
Article in English | MEDLINE | ID: covidwho-1121386
5.
Chest ; 159(1): e35-e38, 2021 01.
Article in English | MEDLINE | ID: covidwho-1002398

ABSTRACT

CASE PRESENTATION: A 28-year-old man presented with shortness of breath, chest pain, and scant hemoptysis. Three weeks previously, he was admitted for coronavirus disease 2019 pneumonia that had been diagnosed by nasal swab polymerase chain reaction. Chest CT imaging demonstrated bilateral ground-glass opacities without evidence of VTE. He was treated with hydroxychloroquine, up to 7 L/min oxygen, and self-proning. After 8 days of hospitalization, he was discharged on 4 L/min oxygen. After discharge, his symptoms and hypoxia resolved.


Subject(s)
COVID-19/complications , Chest Pain/etiology , Dyspnea/etiology , Hemoptysis/etiology , Adult , Chest Pain/therapy , Dyspnea/therapy , Hemoptysis/therapy , Humans , Male
6.
Am J Respir Crit Care Med ; 203(5): 645-646, 2021 03 01.
Article in English | MEDLINE | ID: covidwho-999365
7.
Med Hypotheses ; 146: 110394, 2021 Jan.
Article in English | MEDLINE | ID: covidwho-919589

ABSTRACT

No definitive treatment for COVID-19 exists although promising results have been reported with remdesivir and glucocorticoids. Short of a truly effective preventive or curative vaccine against SARS-CoV-2, it is becoming increasingly clear that multiple pathophysiologic processes seen with COVID-19 as well as SARS-CoV-2 itself should be targeted. Because alpha-1-antitrypsin (AAT) embraces a panoply of biologic activities that may antagonize several pathophysiologic mechanisms induced by SARS-CoV-2, we hypothesize that this naturally occurring molecule is a promising agent to ameliorate COVID-19. We posit at least seven different mechanisms by which AAT may alleviate COVID-19. First, AAT is a serine protease inhibitor (SERPIN) shown to inhibit TMPRSS-2, the host serine protease that cleaves the spike protein of SARS-CoV-2, a necessary preparatory step for the virus to bind its cell surface receptor ACE2 to gain intracellular entry. Second, AAT has anti-viral activity against other RNA viruses HIV and influenza as well as induces autophagy, a known host effector mechanism against MERS-CoV, a related coronavirus that causes the Middle East Respiratory Syndrome. Third, AAT has potent anti-inflammatory properties, in part through inhibiting both nuclear factor-kappa B (NFκB) activation and ADAM17 (also known as tumor necrosis factor-alpha converting enzyme), and thus may dampen the hyper-inflammatory response of COVID-19. Fourth, AAT inhibits neutrophil elastase, a serine protease that helps recruit potentially injurious neutrophils and implicated in acute lung injury. AAT inhibition of ADAM17 also prevents shedding of ACE2 and hence may preserve ACE2 inhibition of bradykinin, reducing the ability of bradykinin to cause a capillary leak in COVID-19. Fifth, AAT inhibits thrombin, and venous thromboembolism and in situ microthrombi and macrothrombi are increasingly implicated in COVID-19. Sixth, AAT inhibition of elastase can antagonize the formation of neutrophil extracellular traps (NETs), a complex extracellular structure comprised of neutrophil-derived DNA, histones, and proteases, and implicated in the immunothrombosis of COVID-19; indeed, AAT has been shown to change the shape and adherence of non-COVID-19-related NETs. Seventh, AAT inhibition of endothelial cell apoptosis may limit the endothelial injury linked to severe COVID-19-associated acute lung injury, multi-organ dysfunction, and pre-eclampsia-like syndrome seen in gravid women. Furthermore, because both NETs formation and the presence of anti-phospholipid antibodies are increased in both COVID-19 and non-COVID pre-eclampsia, it suggests a similar vascular pathogenesis in both disorders. As a final point, AAT has an excellent safety profile when administered to patients with AAT deficiency and is dosed intravenously once weekly but also comes in an inhaled preparation. Thus, AAT is an appealing drug candidate to treat COVID-19 and should be studied.


Subject(s)
COVID-19/drug therapy , Models, Biological , alpha 1-Antitrypsin/therapeutic use , Acute Lung Injury/drug therapy , Anti-Inflammatory Agents/therapeutic use , Antithrombins/therapeutic use , Antiviral Agents/therapeutic use , Apoptosis/drug effects , COVID-19/physiopathology , Extracellular Traps/drug effects , Host Microbial Interactions/drug effects , Host Microbial Interactions/physiology , Humans , Leukocyte Elastase/antagonists & inhibitors , Pandemics , SARS-CoV-2/drug effects , SARS-CoV-2/pathogenicity , SARS-CoV-2/physiology , Serine Endopeptidases/drug effects , Serine Endopeptidases/physiology , Virus Internalization/drug effects , alpha 1-Antitrypsin/administration & dosage
8.
Immune Netw ; 20(5): e41, 2020 Oct.
Article in English | MEDLINE | ID: covidwho-916491

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) is a positive-sense single-stranded RNA (+ssRNA) that causes coronavirus disease 2019 (COVID-19). The viral genome encodes twelve genes for viral replication and infection. The third open reading frame is the spike (S) gene that encodes for the spike glycoprotein interacting with specific cell surface receptor - angiotensin converting enzyme 2 (ACE2) - on the host cell membrane. Most recent studies identified a single point mutation in S gene. A single point mutation in S gene leading to an amino acid substitution at codon 614 from an aspartic acid 614 into glycine (D614G) resulted in greater infectivity compared to the wild type SARS-CoV2. We were interested in investigating the mutation region of S gene of SARS-CoV2 from Korean COVID-19 patients. New mutation sites were found in the critical receptor binding domain (RBD) of S gene, which is adjacent to the aforementioned D614G mutation residue. This specific sequence data demonstrated the active progression of SARS-CoV2 by mutations in the RBD of S gene. The sequence information of new mutations is critical to the development of recombinant SARS-CoV2 spike antigens, which may be required to improve and advance the strategy against a wide range of possible SARS-CoV2 mutations.

SELECTION OF CITATIONS
SEARCH DETAIL