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1.
Int J Mol Sci ; 22(5)2021 Mar 04.
Article in English | MEDLINE | ID: covidwho-1389392

ABSTRACT

Alveolar type II (ATII) cells are a key structure of the distal lung epithelium, where they exert their innate immune response and serve as progenitors of alveolar type I (ATI) cells, contributing to alveolar epithelial repair and regeneration. In the healthy lung, ATII cells coordinate the host defense mechanisms, not only generating a restrictive alveolar epithelial barrier, but also orchestrating host defense mechanisms and secreting surfactant proteins, which are important in lung protection against pathogen exposure. Moreover, surfactant proteins help to maintain homeostasis in the distal lung and reduce surface tension at the pulmonary air-liquid interface, thereby preventing atelectasis and reducing the work of breathing. ATII cells may also contribute to the fibroproliferative reaction by secreting growth factors and proinflammatory molecules after damage. Indeed, various acute and chronic diseases are associated with intensive inflammation. These include oedema, acute respiratory distress syndrome, fibrosis and numerous interstitial lung diseases, and are characterized by hyperplastic ATII cells which are considered an essential part of the epithelialization process and, consequently, wound healing. The aim of this review is that of revising the physiologic and pathologic role ATII cells play in pulmonary diseases, as, despite what has been learnt in the last few decades of research, the origin, phenotypic regulation and crosstalk of these cells still remain, in part, a mystery.


Subject(s)
Alveolar Epithelial Cells/pathology , Alveolar Epithelial Cells/physiology , Lung Diseases/physiopathology , Lung/physiology , Alveolar Epithelial Cells/cytology , Animals , COVID-19/physiopathology , Humans , Immunity, Innate , Ions/metabolism , Lung/anatomy & histology , Lung Diseases/etiology , Lung Diseases/pathology , Pulmonary Surfactant-Associated Proteins/metabolism , Regeneration
2.
Cell Signal ; 85: 110064, 2021 09.
Article in English | MEDLINE | ID: covidwho-1272329

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of coronavirus disease 2019, it binds to angiotensin-converting enzyme 2 (ACE2) to enter into human cells. The expression level of ACE2 potentially determine the susceptibility and severity of COVID-19, it is thus of importance to understand the regulatory mechanism of ACE2 expression. Tripartite motif containing 28 (TRIM28) is known to be involved in multiple processes including antiviral restriction, endogenous retrovirus latency and immune response, it is recently reported to be co-expressed with SARS-CoV-2 receptor in type II pneumocytes; however, the roles of TRIM28 in ACE2 expression and SARS-CoV-2 cell entry remain unclear. This study showed that knockdown of TRIM28 induces ACE2 expression and increases pseudotyped SARS-CoV-2 cell entry of A549 cells and primary pulmonary alveolar epithelial cells (PAEpiCs). In a co-culture model of NK cells and lung epithelial cells, our results demonstrated that NK cells inhibit TRIM28 and promote ACE2 expression in lung epithelial cells, which was partially reversed by depletion of interleukin-2 and blocking of granzyme B in the co-culture medium. Furthermore, TRIM28 knockdown enhanced interferon-γ (IFN-γ)- induced ACE2 expression through a mechanism involving upregulating IFN-γ receptor 2 (IFNGR2) in both A549 and PAEpiCs. The upregulated ACE2 induced by TRIM28 knockdown and co-culture of NK cells was partially reversed by dexamethasone in A549 cells. Our study identified TRIM28 as a novel regulator of ACE2 expression and SARS-CoV-2 cell entry.


Subject(s)
Angiotensin-Converting Enzyme 2/drug effects , Antiviral Agents/pharmacology , SARS-CoV-2/pathogenicity , Tripartite Motif-Containing Protein 28/immunology , Virus Internalization/drug effects , Alveolar Epithelial Cells/metabolism , Alveolar Epithelial Cells/virology , Angiotensin-Converting Enzyme 2/immunology , Epithelial Cells/metabolism , Epithelial Cells/virology , Humans , Lung/metabolism , Lung/virology , Peptidyl-Dipeptidase A/metabolism , Tripartite Motif-Containing Protein 28/drug effects
3.
Heliyon ; 7(5): e07134, 2021 May.
Article in English | MEDLINE | ID: covidwho-1240373

ABSTRACT

Most COVID-19 victims are old and die from unrelated causes. Here we present twelve complete autopsies, including two rapid autopsies of young patients where the cause of death was COVID-19 ARDS. The main virus induced pathology was in the lung parenchyma and not in the airways. Most coagulation events occurred in the intra-alveolar and not in the intra-vascular space and the few thrombi were mainly composed of aggregated thrombocytes. The dominant inflammatory response was the massive accumulation of CD163 + macrophages and the disappearance of T killer, NK and B-cells. The virus was replicating in the pneumocytes and macrophages but not in bronchial epithelium, endothelium, pericytes or stromal cells. The lung consolidations were produced by a massive regenerative response, stromal and epithelial proliferation and neovascularization. We suggest that thrombocyte aggregation inhibition, angiogenesis inhibition and general proliferation inhibition may have a roll in the treatment of advanced COVID-19 ARDS.

4.
Physiol Rep ; 9(9): e14854, 2021 05.
Article in English | MEDLINE | ID: covidwho-1229494

ABSTRACT

SARS-CoV-2 uptake by lung epithelial cells is a critical step in the pathogenesis of COVID-19. Viral entry is dependent on the binding of the viral spike protein to the angiotensin converting enzyme II protein (ACE2) on the host cell surface, followed by proteolytic cleavage by a host serine protease such as TMPRSS2. Infection of alveolar epithelial cells (AEC) in the distal lung is a key feature in progression to the acute respiratory distress syndrome (ARDS). We hypothesized that AEC expression of ACE2 is induced by hypoxia. In a murine model of hypoxic stress (12% FiO2), the total lung Ace2 mRNA and protein expression was significantly increased after 24 hours in hypoxia compared to normoxia (21% FiO2). In experiments with primary murine type II AEC, we found that exposure to hypoxia either in vivo (prior to isolation) or in vitro resulted in greatly increased AEC expression of both Ace2 (mRNA and protein) and of Tmprss2. However, when isolated type II AEC were maintained in culture over 5 days, with loss of type II cell characteristics and induction of type I cell features, Ace2 expression was greatly reduced, suggesting that this expression was a feature of only this subset of AEC. Finally, in primary human small airway epithelial cells (SAEC), ACE2 mRNA and protein expression were also induced by hypoxia, as was binding to purified spike protein. Hypoxia-induced increase in ACE2 expression in type II AEC may provide an explanation of the extended temporal course of human patients who develop ARDS in COVID-19.


Subject(s)
Acute Lung Injury/enzymology , Alveolar Epithelial Cells/enzymology , Angiotensin-Converting Enzyme 2/biosynthesis , COVID-19/enzymology , Gene Expression Regulation, Enzymologic , Hypoxia/enzymology , Acute Lung Injury/genetics , Angiotensin-Converting Enzyme 2/genetics , Animals , COVID-19/genetics , Cells, Cultured , Female , Humans , Hypoxia/genetics , Male , Mice , Mice, Inbred C57BL
5.
ACS Appl Mater Interfaces ; 13(21): 24477-24486, 2021 Jun 02.
Article in English | MEDLINE | ID: covidwho-1219585

ABSTRACT

The pseudovirus strategy makes studies of highly pathogenic viruses feasible without the restriction of high-level biosafety facility, thus greatly contributing to virology and is used in the research studies of SARS-CoV-2. Here, we generated a dual-color pseudo-SARS-CoV-2 virus using a human immunodeficiency virus-1 pseudovirus production system and the SARS-CoV-2 spike (S) glycoprotein, of which the membrane was labeled with a lipophilic dye (DiO) and the genomic RNA-related viral protein R (Vpr) of the viral core was fused with mCherry. With this dual-color labeling strategy, not only the movement of the whole virus but also the fate of the labeled components can be traced. The pseudovirions were applied to track the viral entry at a single-particle level in four types of the human respiratory cells: nasal epithelial cells (HNEpC), pulmonary alveolar epithelial cells (HPAEpiC), bronchial epithelial cells (BEP-2D), and oral epithelial cells (HOEC). Pseudo-SARS-CoV-2 entered into the host cell and released the viral core into the cytoplasm, which clearly indicates that the host entry mainly occurred through endocytosis. The infection efficiency was found to be correlated with the expression of the known receptor of SARS-CoV-2, angiotensin-converting 2 (ACE2) on the host cell surface. We believe that the dual-color fluorescently labeled pseudovirus system created in this study can be applied as a useful tool for many purposes in SARS-CoV-2/COVID-19.


Subject(s)
Fluorescent Dyes/chemistry , Pulmonary Alveoli/virology , SARS-CoV-2/physiology , Virus Internalization , Angiotensin-Converting Enzyme 2/metabolism , Endocytosis , Epithelial Cells/virology , Fluorescence , HEK293 Cells , HIV-1/genetics , Humans , Nasal Mucosa/virology , SARS-CoV-2/genetics , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/metabolism
6.
Vaccines (Basel) ; 9(5)2021 Apr 29.
Article in English | MEDLINE | ID: covidwho-1217123

ABSTRACT

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a severe pandemic of the current century. The vicious tentacles of the disease have been disseminated worldwide with unknown complications and repercussions. Advanced COVID-19 syndrome is characterized by the uncontrolled and elevated release of pro-inflammatory cytokines and suppressed immunity, leading to the cytokine storm. The uncontrolled and dysregulated secretion of inflammatory and pro-inflammatory cytokines is positively associated with the severity of the viral infection and mortality rate. The secretion of various pro-inflammatory cytokines such as TNF-α, IL-1, and IL-6 leads to a hyperinflammatory response by recruiting macrophages, T and B cells in the lung alveolar cells. Moreover, it has been hypothesized that immune cells such as macrophages recruit inflammatory monocytes in the alveolar cells and allow the production of large amounts of cytokines in the alveoli, leading to a hyperinflammatory response in severely ill patients with COVID-19. This cascade of events may lead to multiple organ failure, acute respiratory distress, or pneumonia. Although the disease has a higher survival rate than other chronic diseases, the incidence of complications in the geriatric population are considerably high, with more systemic complications. This review sheds light on the pivotal roles played by various inflammatory markers in COVID-19-related complications. Different molecular pathways, such as the activation of JAK and JAK/STAT signaling are crucial in the progression of cytokine storm; hence, various mechanisms, immunological pathways, and functions of cytokines and other inflammatory markers have been discussed. A thorough understanding of cytokines' molecular pathways and their activation procedures will add more insight into understanding immunopathology and designing appropriate drugs, therapies, and control measures to counter COVID-19. Recently, anti-inflammatory drugs and several antiviral drugs have been reported as effective therapeutic drug candidates to control hypercytokinemia or cytokine storm. Hence, the present review also discussed prospective anti-inflammatory and relevant immunomodulatory drugs currently in various trial phases and their possible implications.

7.
J Immunol ; 206(10): 2420-2429, 2021 05 15.
Article in English | MEDLINE | ID: covidwho-1215526

ABSTRACT

We have recently shown that type 2 transglutaminase (TG2) plays a key role in the host's inflammatory response during bacterial infections. In this study, we investigated whether the enzyme is involved in the regulation of the STING pathway, which is the main signaling activated in the presence of both self- and pathogen DNA in the cytoplasm, leading to type I IFN (IFN I) production. In this study, we demonstrated that TG2 negatively regulates STING signaling by impairing IRF3 phosphorylation in bone marrow-derived macrophages, isolated from wild-type and TG2 knockout mice. In the absence of TG2, we found an increase in the IFN-ß production and in the downstream JAK/STAT pathway activation. Interestingly, proteomic analysis revealed that TG2 interacts with TBK1, affecting its interactome composition. Indeed, TG2 ablation facilitates the TBK1-IRF3 interaction, thus indicating that the enzyme plays a negative regulatory effect on IRF3 recruitment in the STING/TBK1 complex. In keeping with these findings, we observed an increase in the IFNß production in bronchoalveolar lavage fluids from COVID-19-positive dead patients paralleled by a dramatic decrease of the TG2 expression in the lung pneumocytes. Taken together, these results suggest that TG2 plays a negative regulation on the IFN-ß production associated with the innate immunity response to the cytosolic presence of both self- and pathogen DNA.


Subject(s)
COVID-19/immunology , GTP-Binding Proteins/immunology , Immunity, Innate , Interferon Regulatory Factor-3/immunology , Membrane Proteins/immunology , SARS-CoV-2/immunology , Signal Transduction/immunology , Transglutaminases/immunology , Animals , COVID-19/genetics , COVID-19/pathology , GTP-Binding Proteins/genetics , Humans , Interferon Regulatory Factor-3/genetics , Interferon-beta/genetics , Interferon-beta/immunology , Membrane Proteins/genetics , Mice , Mice, Knockout , Signal Transduction/genetics , Transglutaminases/genetics
8.
Pathogens ; 10(5)2021 Apr 23.
Article in English | MEDLINE | ID: covidwho-1201175

ABSTRACT

The SARS-CoV-2 pandemic has inspired renewed interest in understanding the fundamental pathology of acute respiratory distress syndrome (ARDS) following infection. However, the pathogenesis of ARDS following SRAS-CoV-2 infection remains largely unknown. In the present study, we examined apoptosis in postmortem lung sections from COVID-19 patients and in lung tissues from a non-human primate model of SARS-CoV-2 infection, in a cell-type manner, including type 1 and 2 alveolar cells and vascular endothelial cells (ECs), macrophages, and T cells. Multiple-target immunofluorescence assays and Western blotting suggest both intrinsic and extrinsic apoptotic pathways are activated during SARS-CoV-2 infection. Furthermore, we observed that SARS-CoV-2 fails to induce apoptosis in human bronchial epithelial cells (i.e., BEAS2B cells) and primary human umbilical vein endothelial cells (HUVECs), which are refractory to SARS-CoV-2 infection. However, infection of co-cultured Vero cells and HUVECs or Vero cells and BEAS2B cells with SARS-CoV-2 induced apoptosis in both Vero cells and HUVECs/BEAS2B cells but did not alter the permissiveness of HUVECs or BEAS2B cells to the virus. Post-exposure treatment of the co-culture of Vero cells and HUVECs with a novel non-cyclic nucleotide small molecule EPAC1-specific activator reduced apoptosis in HUVECs. These findings may help to delineate a novel insight into the pathogenesis of ARDS following SARS-CoV-2 infection.

9.
Viruses ; 13(4)2021 04 09.
Article in English | MEDLINE | ID: covidwho-1178431

ABSTRACT

The spike glycoprotein attached to the envelope of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) binds to and exploits angiotensin-converting enzyme 2 (ACE2) as an entry receptor to infect pulmonary epithelial cells. A subset of integrins that recognize the arginyl-glycyl-aspartic acid (RGD) sequence in the cognate ligands has been predicted in silico to bind the spike glycoprotein and, thereby, to be exploited for viral infection. Here, we show experimental evidence that the ß1 integrins predominantly expressed on human pulmonary epithelial cell lines and primary mouse alveolar epithelial cells bind to this spike protein. The cellular ß1 integrins support adhesive interactions with the spike protein independently of ACE2, suggesting the possibility that the ß1 integrins may function as an alternative receptor for SARS-CoV-2, which could be targeted for the prevention of viral infections.


Subject(s)
Alveolar Epithelial Cells/metabolism , Integrin beta1/metabolism , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Angiotensin-Converting Enzyme 2/metabolism , Animals , COVID-19/virology , Cell Adhesion , Cell Line , Humans , Lung/metabolism , Mice , Mice, Inbred C57BL , Oligopeptides , Protein Binding , Receptors, Virus/metabolism , THP-1 Cells , Virus Internalization
10.
Nature ; 594(7861): 88-93, 2021 06.
Article in English | MEDLINE | ID: covidwho-1171428

ABSTRACT

COVID-19 is a disease with unique characteristics that include lung thrombosis1, frequent diarrhoea2, abnormal activation of the inflammatory response3 and rapid deterioration of lung function consistent with alveolar oedema4. The pathological substrate for these findings remains unknown. Here we show that the lungs of patients with COVID-19 contain infected pneumocytes with abnormal morphology and frequent multinucleation. The generation of these syncytia results from activation of the SARS-CoV-2 spike protein at the cell plasma membrane level. On the basis of these observations, we performed two high-content microscopy-based screenings with more than 3,000 approved drugs to search for inhibitors of spike-driven syncytia. We converged on the identification of 83 drugs that inhibited spike-mediated cell fusion, several of which belonged to defined pharmacological classes. We focused our attention on effective drugs that also protected against virus replication and associated cytopathicity. One of the most effective molecules was the antihelminthic drug niclosamide, which markedly blunted calcium oscillations and membrane conductance in spike-expressing cells by suppressing the activity of TMEM16F (also known as anoctamin 6), a calcium-activated ion channel and scramblase that is responsible for exposure of phosphatidylserine on the cell surface. These findings suggest a potential mechanism for COVID-19 disease pathogenesis and support the repurposing of niclosamide for therapy.


Subject(s)
Anoctamins/antagonists & inhibitors , COVID-19/pathology , Cell Fusion , Drug Evaluation, Preclinical , Giant Cells/drug effects , SARS-CoV-2/drug effects , Spike Glycoprotein, Coronavirus/antagonists & inhibitors , Aged , Aged, 80 and over , Alveolar Epithelial Cells/drug effects , Alveolar Epithelial Cells/pathology , Alveolar Epithelial Cells/virology , Animals , Anoctamins/metabolism , COVID-19/metabolism , COVID-19/virology , Calcium Signaling/drug effects , Cell Line , Chloride Channels/metabolism , Chlorocebus aethiops , Female , Giant Cells/metabolism , Giant Cells/virology , Humans , Lung/drug effects , Lung/pathology , Lung/virology , Male , SARS-CoV-2/metabolism , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/metabolism , Virus Replication/drug effects
11.
Front Med (Lausanne) ; 8: 640073, 2021.
Article in English | MEDLINE | ID: covidwho-1121618

ABSTRACT

Although SARS-CoV-2 is considered a lung-tropic virus that infects the respiratory tract through binding to the ACE2 cell-surface molecules present on alveolar lungs epithelial cells, gastrointestinal symptoms have been frequently reported in COVID-19 patients. What can be considered an apparent paradox is that these symptoms (e.g., diarrhea), sometimes precede the development of respiratory tract illness as if the breathing apparatus was not its first target during viral dissemination. Recently, evidence was reported that the gut is an active site of replication for SARS-CoV-2. This replication mainly occurs in mature enterocytes expressing the ACE2 viral receptor and TMPRSS4 protease. In this review we question how SARS-CoV-2 can cause intestinal disturbances, whether there are pneumocyte-tropic, enterocyte-tropic and/or dual tropic strains of SARS-CoV-2. We examine two major models: first, that of a virus directly causing damage locally (e.g., by inducing apoptosis of infected enterocytes); secondly, that of indirect effect of the virus (e.g., by inducing changes in the composition of the gut microbiota followed by the induction of an inflammatory process), and suggest that both situations probably occur simultaneously in COVID-19 patients. We eventually discuss the consequences of the virus replication in brush border of intestine on long-distance damages affecting other tissues/organs, particularly lungs.

12.
J Infect Dis ; 223(5): 752-764, 2021 03 03.
Article in English | MEDLINE | ID: covidwho-1117027

ABSTRACT

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic continues to produce substantial morbidity and mortality. To understand the reasons for the wide-spectrum complications and severe outcomes of COVID-19, we aimed to identify cellular targets of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) tropism and replication in various tissues. METHODS: We evaluated RNA extracted from formalin-fixed, paraffin-embedded autopsy tissues from 64 case patients (age range, 1 month to 84 years; 21 COVID-19 confirmed, 43 suspected COVID-19) by SARS-CoV-2 reverse-transcription polymerase chain reaction (RT-PCR). For cellular localization of SARS-CoV-2 RNA and viral characterization, we performed in situ hybridization (ISH), subgenomic RNA RT-PCR, and whole-genome sequencing. RESULTS: SARS-CoV-2 was identified by RT-PCR in 32 case patients (21 COVID-19 confirmed, 11 suspected). ISH was positive in 20 and subgenomic RNA RT-PCR was positive in 17 of 32 RT-PCR-positive case patients. SARS-CoV-2 RNA was localized by ISH in hyaline membranes, pneumocytes, and macrophages of lungs; epithelial cells of airways; and endothelial cells and vessel walls of brain stem, leptomeninges, lung, heart, liver, kidney, and pancreas. The D614G variant was detected in 9 RT-PCR-positive case patients. CONCLUSIONS: We identified cellular targets of SARS-CoV-2 tropism and replication in the lungs and airways and demonstrated its direct infection in vascular endothelium. This work provides important insights into COVID-19 pathogenesis and mechanisms of severe outcomes.


Subject(s)
COVID-19/virology , Endothelium, Vascular/virology , Respiratory System/virology , SARS-CoV-2/physiology , Virus Replication , Adolescent , Adult , Aged , Aged, 80 and over , Autopsy , COVID-19/complications , COVID-19 Nucleic Acid Testing , Child , Child, Preschool , Female , Humans , In Situ Hybridization , Infant , Lung/virology , Male , Middle Aged , RNA, Viral/isolation & purification , Real-Time Polymerase Chain Reaction , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification , Viral Tropism , Whole Genome Sequencing , Young Adult
13.
Cancers (Basel) ; 13(4)2021 Feb 11.
Article in English | MEDLINE | ID: covidwho-1090373

ABSTRACT

The anti-cancer antitumor antibiotic bleomycin(s) (BLM) induces athyminic sites in DNA after its activation, a process that results in strand splitting. Here, using A549 human lung cells or BEAS-2B cells lunc cells, we show that the cell toxicity of BLM can be suppressed by addition of inorganic polyphosphate (polyP), a physiological polymer that accumulates and is released from platelets. BLM at a concentration of 20 µg ml-1 causes a decrease in cell viability (by ~70%), accompanied by an increased DNA damage and chromatin expansion (by amazingly 6-fold). Importantly, the BLM-caused effects on cell growth and DNA integrity are substantially suppressed by polyP. In parallel, the enlargement of the nuclei/chromatin in BLM-treated cells (diameter, 20-25 µm) is normalized to ~12 µm after co-incubation of the cells with BLM and polyP. A sequential application of the drugs (BLM for 3 days, followed by an exposure to polyP) does not cause this normalization. During co-incubation of BLM with polyP the gene for the BLM hydrolase is upregulated. It is concluded that by upregulating this enzyme polyP prevents the toxic side effects of BLM. These data might also contribute to an application of BLM in COVID-19 patients, since polyP inhibits binding of SARS-CoV-2 to cellular ACE2.

14.
Infect Dis (Auckl) ; 14: 1178633721994605, 2021.
Article in English | MEDLINE | ID: covidwho-1088428

ABSTRACT

BACKGROUND: Angiotensin-converting enzyme II or ACE2 is an integral membrane protein present on many types of cells, including vascular endothelial cells and lung alveolar epithelial cells. This receptor serves as the entry point for SARS-coronaviruses (SARS-CoVs), including a novel coronavirus 2019-nCoV. Limited availability of these receptors can thwart cellular entry of this virus. METHODS: We tested the effects of ascorbic acid (vitamin C) on cellular expression of ACE2 at the protein and RNA levels in human small alveolar epithelial cells and microvascular endothelial cells. In addition, we investigated whether combinations of ascorbic acid with other natural compounds can affect ACE2 expression. RESULTS: The results show that ascorbic acid itself has moderate but consistent lowering effects on ACE2 expression at the cellular, protein, and RNA levels. Some natural compounds were effective in lowering ACE2 cellular expression, with the highest inhibitory effects observed for baicalin (75%) and theaflavin (50%). Significantly, combinations of these and other test compounds with ascorbic acid further decreased ACE2 expression. The highest impact of ascorbate on ACE2 expression was noted when combined with theaflavin (decrease from 50% to 87%), zinc (decrease from 22% to 62%), and with 10-undecenoic acid (from 18% to 53%). Ascorbic acid showed moderate additional benefits in decreasing ACE2 expression when combined with N-acetylcysteine and baicalin. CONCLUSION: Our study provides valuable experimental confirmation of the efficacy of micronutrients in controlling ACE2 expression-the coronavirus cellular "entry" point. It further validates the importance of nutrient interactions in various aspects of cellular metabolism and in considering potential therapeutic applications of nutrient-based approaches. The study shows that ascorbic acid and its combination with some natural compounds could be included in developing preventive and therapeutic approaches toward the current pandemic.

15.
Viruses ; 13(2)2021 02 16.
Article in English | MEDLINE | ID: covidwho-1085035

ABSTRACT

Background: Coronavirus disease 19 (COVID-19) can develop into a severe respiratory syndrome that results in up to 40% mortality. Acute lung inflammatory edema is a major pathological finding in autopsies explaining O2 diffusion failure and hypoxemia. Only dexamethasone has been shown to reduce mortality in severe cases, further supporting a role for inflammation in disease severity. SARS-CoV-2 enters cells employing angiotensin-converting enzyme 2 (ACE2) as a receptor, which is highly expressed in lung alveolar cells. ACE2 is one of the components of the cellular machinery that inactivates the potent inflammatory agent bradykinin, and SARS-CoV-2 infection could interfere with the catalytic activity of ACE2, leading to the accumulation of bradykinin. Methods: In this case control study, we tested two pharmacological inhibitors of the kinin-kallikrein system that are currently approved for the treatment of hereditary angioedema, icatibant, and inhibitor of C1 esterase/kallikrein, in a group of 30 patients with severe COVID-19. Results: Neither icatibant nor inhibitor of C1 esterase/kallikrein resulted in changes in time to clinical improvement. However, both compounds were safe and promoted the significant improvement of lung computed tomography scores and increased blood eosinophils, which are indicators of disease recovery. Conclusions: In this small cohort, we found evidence for safety and a beneficial role of pharmacological inhibition of the kinin-kallikrein system in two markers that indicate improved disease recovery.


Subject(s)
Bradykinin/analogs & derivatives , COVID-19/drug therapy , Complement C1 Inhibitor Protein/therapeutic use , Kallikrein-Kinin System/drug effects , Kallikreins/antagonists & inhibitors , Adult , Aged , Bradykinin/therapeutic use , Case-Control Studies , Drug Repositioning , Female , Humans , Lung/drug effects , Lung/pathology , Male , Middle Aged
16.
Viruses ; 13(2)2021 Jan 20.
Article in English | MEDLINE | ID: covidwho-1067780

ABSTRACT

Although ACE2 (angiotensin converting enzyme 2) is considered the primary receptor for CoV-2 cell entry, recent reports suggest that alternative pathways may contribute. This paper considers the hypothesis that viral binding to cell-surface integrins may contribute to the high infectivity and widespread extra-pulmonary impacts of the SARS-CoV-2 virus. This potential is suggested on the basis of the emergence of an RGD (arginine-glycine-aspartate) sequence in the receptor-binding domain of the spike protein. RGD is a motif commonly used by viruses to bind cell-surface integrins. Numerous signaling pathways are mediated by integrins and virion binding could lead to dysregulation of these pathways, with consequent tissue damage. Integrins on the surfaces of pneumocytes, endothelial cells and platelets may be vulnerable to CoV-2 virion binding. For instance, binding of intact virions to integrins on alveolar cells could enhance viral entry. Binding of virions to integrins on endothelial cells could activate angiogenic cell signaling pathways; dysregulate integrin-mediated signaling pathways controlling developmental processes; and precipitate endothelial activation to initiate blood clotting. Such a procoagulant state, perhaps together with enhancement of platelet aggregation through virions binding to integrins on platelets, could amplify the production of microthrombi that pose the threat of pulmonary thrombosis and embolism, strokes and other thrombotic consequences. The susceptibility of different tissues to virion-integrin interactions may be modulated by a host of factors, including the conformation of relevant integrins and the impact of the tissue microenvironment on spike protein conformation. Patient-specific differences in these factors may contribute to the high variability of clinical presentation. There is danger that the emergence of receptor-binding domain mutations that increase infectivity may also enhance access of the RGD motif for integrin binding, resulting in viral strains with ACE2 independent routes of cell entry and novel integrin-mediated biological and clinical impacts. The highly infectious variant, B.1.1.7 (or VUI 202012/01), includes a receptor-binding domain amino acid replacement, N501Y, that could potentially provide the RGD motif with enhanced access to cell-surface integrins, with consequent clinical impacts.


Subject(s)
Integrins/metabolism , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism , Blood Coagulation Disorders/virology , COVID-19/blood , COVID-19/pathology , COVID-19/virology , Humans , Neovascularization, Pathologic/virology , Oligopeptides , Protein Binding , Receptors, Virus/metabolism , SARS-CoV-2/pathogenicity , Signal Transduction , Virus Internalization
17.
Sci Rep ; 11(1): 1462, 2021 01 14.
Article in English | MEDLINE | ID: covidwho-1065941

ABSTRACT

Cannabis sativa is widely used for medical purposes and has anti-inflammatory activity. This study intended to examine the anti-inflammatory activity of cannabis on immune response markers associated with coronavirus disease 2019 (COVID-19) inflammation. An extract fraction from C. sativa Arbel strain (FCBD) substantially reduced (dose dependently) interleukin (IL)-6 and -8 levels in an alveolar epithelial (A549) cell line. FCBD contained cannabidiol (CBD), cannabigerol (CBG) and tetrahydrocannabivarin (THCV), and multiple terpenes. Treatments with FCBD and a FCBD formulation using phytocannabinoid standards (FCBD:std) reduced IL-6, IL-8, C-C Motif Chemokine Ligands (CCLs) 2 and 7, and angiotensin I converting enzyme 2 (ACE2) expression in the A549 cell line. Treatment with FCBD induced macrophage (differentiated KG1 cell line) polarization and phagocytosis in vitro, and increased CD36 and type II receptor for the Fc region of IgG (FcγRII) expression. FCBD treatment also substantially increased IL-6 and IL-8 expression in macrophages. FCBD:std, while maintaining anti-inflammatory activity in alveolar epithelial cells, led to reduced phagocytosis and pro-inflammatory IL secretion in macrophages in comparison to FCBD. The phytocannabinoid formulation may show superior activity versus the cannabis-derived fraction for reduction of lung inflammation, yet there is a need of caution proposing cannabis as treatment for COVID-19.


Subject(s)
Anti-Inflammatory Agents/pharmacology , COVID-19/immunology , Cannabinoids/pharmacology , Cannabis/chemistry , Epithelial Cells/immunology , Macrophages/immunology , Plant Extracts/pharmacology , SARS-CoV-2/immunology , A549 Cells , Angiotensin-Converting Enzyme 2/immunology , Anti-Inflammatory Agents/chemistry , COVID-19/drug therapy , COVID-19/pathology , Cannabinoids/chemistry , Cytokines/immunology , Epithelial Cells/pathology , Epithelial Cells/virology , Gene Expression Regulation/drug effects , Gene Expression Regulation/immunology , Humans , Macrophages/pathology , Macrophages/virology , Plant Extracts/chemistry , Receptors, IgG/immunology
18.
Cell Rep ; 34(7): 108761, 2021 02 16.
Article in English | MEDLINE | ID: covidwho-1062276

ABSTRACT

Coronavirus disease 2019 (COVID-19) is a current global health threat caused by the novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Emerging evidence indicates that SARS-CoV-2 elicits a dysregulated immune response and a delayed interferon (IFN) expression in patients, which contribute largely to the viral pathogenesis and development of COVID-19. However, underlying mechanisms remain to be elucidated. Here, we report the activation and repression of the innate immune response by SARS-CoV-2. We show that SARS-CoV-2 RNA activates the RIG-I-MAVS-dependent IFN signaling pathway. We further uncover that ORF9b immediately accumulates and antagonizes the antiviral type I IFN response during SARS-CoV-2 infection on primary human pulmonary alveolar epithelial cells. ORF9b targets the nuclear factor κB (NF-κB) essential modulator NEMO and interrupts its K63-linked polyubiquitination upon viral stimulation, thereby inhibiting the canonical IκB kinase alpha (IKKα)/ß/γ-NF-κB signaling and subsequent IFN production. Our findings thus unveil the innate immunosuppression by ORF9b and provide insights into the host-virus interplay during the early stage of SARS-CoV-2 infection.


Subject(s)
Coronavirus Nucleocapsid Proteins/genetics , I-kappa B Kinase/metabolism , SARS-CoV-2/metabolism , Adaptor Proteins, Signal Transducing/metabolism , Alveolar Epithelial Cells/metabolism , Alveolar Epithelial Cells/virology , COVID-19/immunology , COVID-19/metabolism , Coronavirus Nucleocapsid Proteins/metabolism , HEK293 Cells , Humans , Immunity, Innate/immunology , Interferon Type I/metabolism , Interferons/metabolism , NF-kappa B/metabolism , Phosphoproteins/genetics , Phosphoproteins/metabolism , Primary Cell Culture , Receptors, Retinoic Acid/metabolism , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Signal Transduction , Ubiquitination
19.
J Cannabis Res ; 2(1): 23, 2020.
Article in English | MEDLINE | ID: covidwho-1059599

ABSTRACT

BACKGROUND: Coronavirus disease 2019 (COVID-19) is spreading fast all around the world with more than fourteen millions of detected infected cases and more than 600.000 deaths by 20th July 2020. While scientist are working to find a vaccine, current epidemiological data shows that the most common comorbidities for patients with the worst prognosis, hypertension and diabetes, are often treated with angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs). BODY: Both ACE inhibitors and ARBs induce overexpression of the angiotensin converting enzyme 2 (ACE-2) receptor, which has been identified as the main receptor used by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to enter into the alveolar cells of the lungs. While cannabinoids are known to reduce hypertension, the studies testing the hypotensive effects of cannabinoids never addressed their effects on ACE-2 receptors. However, some studies have linked the endocannabinoid system (ECS) with the renin angiotensin system (RAS), including a cross-modulation between the cannabinoid receptor 1 (CB1) and angiotensin II levels. CONCLUSION: Since there are around 192 million people using cannabis worldwide, we believe that the mechanism underlying the hypotensive properties of cannabinoids should be urgently studied to understand if they can also lead to ACE-2 overexpression as other antihypertensive drugs do.

20.
Br J Pharmacol ; 177(21): 4971-4974, 2020 11.
Article in English | MEDLINE | ID: covidwho-998832

ABSTRACT

In the search to rapidly identify effective therapies that will mitigate the morbidity and mortality of COVID-19, attention has been directed towards the repurposing of existing drugs. Candidates for repurposing include drugs that target COVID-19 pathobiology, including agents that alter angiotensin signalling. Recent data indicate that key findings in COVID-19 patients include thrombosis and endotheliitis. Activation of proteinase-activated receptor 1 (PAR1), in particular by the serine protease thrombin, is a critical element in platelet aggregation and coagulation. PAR1 activation also impacts on the actions of other cell types involved in COVID-19 pathobiology, including endothelial cells, fibroblasts and pulmonary alveolar epithelial cells. Vorapaxar is an approved inhibitor of PAR1, used for treatment of patients with myocardial infarction or peripheral arterial disease. We discuss evidence for a possible beneficial role for vorapaxar in the treatment of COVID-19 patients and other as-yet non-approved antagonists of PAR1 and proteinase-activated receptor 4 (PAR4). LINKED ARTICLES: This article is part of a themed issue on The Pharmacology of COVID-19. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.21/issuetoc.


Subject(s)
Coronavirus Infections/drug therapy , Lactones/administration & dosage , Pneumonia, Viral/drug therapy , Pyridines/administration & dosage , Receptor, PAR-1/antagonists & inhibitors , Animals , Betacoronavirus/isolation & purification , COVID-19 , Coronavirus Infections/virology , Drug Repositioning , Humans , Lactones/pharmacology , Pandemics , Platelet Aggregation Inhibitors/administration & dosage , Platelet Aggregation Inhibitors/pharmacology , Pneumonia, Viral/virology , Pyridines/pharmacology , Receptor, PAR-1/metabolism , Receptors, Thrombin/antagonists & inhibitors , Receptors, Thrombin/metabolism , SARS-CoV-2
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