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1.
J Cell Sci ; 134(19)2021 10 01.
Article in English | MEDLINE | ID: covidwho-1484823

ABSTRACT

Molecular chaperones play an important role during the response to different stresses. Since plants are sessile organisms, they need to be able to adapt quickly to different conditions. To do so, plants possess a complex chaperone machinery, composed of HSP70, HSP90, J proteins and other factors. In this study we characterized DJC31 (also known as TPR16) and DJC62 (also known as TPR15) of Arabidopsis thaliana, two J proteins that additionally carry clamp-type tetratricopeptide repeat domains. Using cell fractionation and split GFP, we could show that both proteins are attached to the cytosolic side of the endoplasmic reticulum membrane. Moreover, an interaction with cytosolic HSP70.1 and HSP90.2 could be shown using bimolecular fluorescence complementation. Knockout of both DJC31 and DJC62 caused severe defects in growth and development, which affected almost all organs. Furthermore, it could be shown that the double mutant is more sensitive to osmotic stress and treatment with abscisic acid, but surprisingly exhibited enhanced tolerance to drought. Taken together, these findings indicate that DJC31 and DJC62 might act as important regulators of chaperone-dependent signaling pathways involved in plant development and stress responses.


Subject(s)
Arabidopsis Proteins , Arabidopsis , Abscisic Acid , Arabidopsis/genetics , Arabidopsis/metabolism , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , Gene Expression Regulation, Plant , HSP90 Heat-Shock Proteins/metabolism , Plants, Genetically Modified/metabolism , Stress, Physiological
3.
Int J Mol Sci ; 22(17)2021 Aug 29.
Article in English | MEDLINE | ID: covidwho-1374429

ABSTRACT

Heat shock proteins (HSPs) are a large group of chaperones found in most eukaryotes and bacteria. They are responsible for the correct protein folding, protection of the cell against stressors, presenting immune and inflammatory cytokines; furthermore, they are important factors in regulating cell differentiation, survival and death. Although the biological function of HSPs is to maintain cell homeostasis, some of them can be used by viruses both to fold their proteins and increase the chances of survival in unfavorable host conditions. Folding viral proteins as well as replicating many different viruses are carried out by, among others, proteins from the HSP70 and HSP90 families. In some cases, the HSP70 family proteins directly interact with viral polymerase to enhance viral replication or they can facilitate the formation of a viral replication complex and/or maintain the stability of complex proteins. It is known that HSP90 is important for the expression of viral genes at both the transcriptional and the translational levels. Both of these HSPs can form a complex with HSP90 and, consequently, facilitate the entry of the virus into the cell. Current studies have shown the biological significance of HSPs in the course of infection SARS-CoV-2. A comprehensive understanding of chaperone use during viral infection will provide new insight into viral replication mechanisms and therapeutic potential. The aim of this study is to describe the molecular basis of HSP70 and HSP90 participation in some viral infections and the potential use of these proteins in antiviral therapy.


Subject(s)
HSP70 Heat-Shock Proteins/metabolism , HSP90 Heat-Shock Proteins/metabolism , Virus Diseases/pathology , COVID-19/metabolism , COVID-19/pathology , COVID-19/virology , DNA Viruses/physiology , Humans , Protein Isoforms/metabolism , RNA Viruses/physiology , SARS-CoV-2/isolation & purification , Virus Diseases/metabolism , Virus Diseases/virology
4.
Int J Mol Sci ; 22(17)2021 Aug 26.
Article in English | MEDLINE | ID: covidwho-1374427

ABSTRACT

SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) is the causative agent of the COVID19 pandemic. The SARS-CoV-2 genome encodes for a small accessory protein termed Orf9b, which targets the mitochondrial outer membrane protein TOM70 in infected cells. TOM70 is involved in a signaling cascade that ultimately leads to the induction of type I interferons (IFN-I). This cascade depends on the recruitment of Hsp90-bound proteins to the N-terminal domain of TOM70. Binding of Orf9b to TOM70 decreases the expression of IFN-I; however, the underlying mechanism remains elusive. We show that the binding of Orf9b to TOM70 inhibits the recruitment of Hsp90 and chaperone-associated proteins. We characterized the binding site of Orf9b within the C-terminal domain of TOM70 and found that a serine in position 53 of Orf9b and a glutamate in position 477 of TOM70 are crucial for the association of both proteins. A phosphomimetic variant Orf9bS53E showed drastically reduced binding to TOM70 and did not inhibit Hsp90 recruitment, suggesting that Orf9b-TOM70 complex formation is regulated by phosphorylation. Eventually, we identified the N-terminal TPR domain of TOM70 as a second binding site for Orf9b, which indicates a so far unobserved contribution of chaperones in the mitochondrial targeting of the viral protein.


Subject(s)
COVID-19/transmission , Coronavirus Nucleocapsid Proteins/metabolism , HSP90 Heat-Shock Proteins/metabolism , Mitochondrial Membrane Transport Proteins/metabolism , SARS-CoV-2/pathogenicity , Animals , Binding Sites/genetics , COVID-19/immunology , COVID-19/virology , Chlorocebus aethiops , Coronavirus Nucleocapsid Proteins/genetics , Coronavirus Nucleocapsid Proteins/immunology , Coronavirus Nucleocapsid Proteins/isolation & purification , Humans , Interferon Type I/immunology , Interferon Type I/metabolism , Mitochondrial Membrane Transport Proteins/genetics , Mitochondrial Membrane Transport Proteins/isolation & purification , Mutation , Phosphoproteins/genetics , Phosphoproteins/immunology , Phosphoproteins/isolation & purification , Phosphoproteins/metabolism , Phosphorylation , Protein Binding/genetics , Protein Binding/immunology , Protein Domains/genetics , Recombinant Proteins/genetics , Recombinant Proteins/immunology , Recombinant Proteins/isolation & purification , Recombinant Proteins/metabolism , SARS-CoV-2/genetics , SARS-CoV-2/metabolism , Vero Cells
5.
Am J Respir Cell Mol Biol ; 65(4): 403-412, 2021 10.
Article in English | MEDLINE | ID: covidwho-1237350

ABSTRACT

Mechanical ventilation is a known risk factor for delirium, a cognitive impairment characterized by dysfunction of the frontal cortex and hippocampus. Although IL-6 is upregulated in mechanical ventilation-induced lung injury (VILI) and may contribute to delirium, it is not known whether the inhibition of systemic IL-6 mitigates delirium-relevant neuropathology. To histologically define neuropathological effects of IL-6 inhibition in an experimental VILI model, VILI was simulated in anesthetized adult mice using a 35 cc/kg tidal volume mechanical ventilation model. There were two control groups, as follow: 1) spontaneously breathing or 2) anesthetized and mechanically ventilated with 10 cc/kg tidal volume to distinguish effects of anesthesia from VILI. Two hours before inducing VILI, mice were treated with either anti-IL-6 antibody, anti-IL-6 receptor antibody, or saline. Neuronal injury, stress, and inflammation were assessed using immunohistochemistry. CC3 (cleaved caspase-3), a neuronal apoptosis marker, was significantly increased in the frontal (P < 0.001) and hippocampal (P < 0.0001) brain regions and accompanied by significant increases in c-Fos and heat shock protein-90 in the frontal cortices of VILI mice compared with control mice (P < 0.001). These findings were not related to cerebral hypoxia, and there was no evidence of irreversible neuronal death. Frontal and hippocampal neuronal CC3 were significantly reduced with anti-IL-6 antibody (P < 0.01 and P < 0.0001, respectively) and anti-IL-6 receptor antibody (P < 0.05 and P < 0.0001, respectively) compared with saline VILI mice. In summary, VILI induces potentially reversible neuronal injury and inflammation in the frontal cortex and hippocampus, which is mitigated with systemic IL-6 inhibition. These data suggest a potentially novel neuroprotective role of systemic IL-6 inhibition that justifies further investigation.


Subject(s)
Antibodies/pharmacology , Apoptosis/drug effects , Delirium/metabolism , Interleukin-6/antagonists & inhibitors , Neurons/metabolism , Ventilator-Induced Lung Injury/metabolism , Animals , Delirium/drug therapy , Delirium/pathology , Disease Models, Animal , Female , Frontal Lobe/injuries , Frontal Lobe/metabolism , Frontal Lobe/pathology , HSP90 Heat-Shock Proteins/metabolism , Hippocampus/injuries , Hippocampus/metabolism , Hippocampus/pathology , Inflammation/drug therapy , Inflammation/metabolism , Inflammation/pathology , Interleukin-6/metabolism , Mice , Neurons/pathology , Proto-Oncogene Proteins c-fos/metabolism , Repressor Proteins/metabolism , Tumor Suppressor Proteins/metabolism , Ventilator-Induced Lung Injury/drug therapy , Ventilator-Induced Lung Injury/pathology
6.
Cell Stress Chaperones ; 26(2): 289-295, 2021 03.
Article in English | MEDLINE | ID: covidwho-1070950

ABSTRACT

Members of the Cell Stress Society International (CSSI), Patricija van Oosten-Hawle (University of Leeds, UK), Mehdi Mollapour (SUNY Upstate Medical University, USA), Andrew Truman (University of North Carolina at Charlotte, USA) organized a new virtual meeting format which took place on November 5-6, 2020. The goal of this congress was to provide an international platform for scientists to exchange data and ideas among the Cell Stress and Chaperones community during the Covid-19 pandemic. Here we will highlight the summary of the meeting and acknowledge those who were honored by the CSSI.


Subject(s)
Heat-Shock Proteins/metabolism , Molecular Chaperones/metabolism , HSP70 Heat-Shock Proteins/genetics , HSP70 Heat-Shock Proteins/metabolism , HSP90 Heat-Shock Proteins/genetics , HSP90 Heat-Shock Proteins/metabolism , Heat-Shock Proteins/genetics , Humans , Molecular Chaperones/genetics , Proteostasis/genetics , Proteostasis/physiology
7.
Chem Biol Interact ; 332: 109299, 2020 Dec 01.
Article in English | MEDLINE | ID: covidwho-885217

ABSTRACT

COVID-2019 pandemic is affecting people worldwide in the absence of an effective treatment strategy. Several suggestive therapeutic options through drug repurposing are recommended, but a complete consensus is not reached. A combination of Hydroxychloroquine (HCQ) and Azithromycin (AZM) has been widely tried and discussed but its administration has also led to potential adversities in patients. Studies are suggesting that most prominent adverse event with HCQ and AZM combination is QT interval prolongation. We studied interaction of HCQ with AZM and subsequent effect of this drug combination on QT interval prolongation. We performed system biological investigation of HCQ and AZM targets and screened important targets and pathways possibly involved in QT interval prolongation. The best core hub protein drug targets involved in QT interval prolongation were identified as HSP90AA1 exclusively associated with HCQ, while AKT1 exclusively associated with AZM on the basis of node degree value. It was found that PI3K/Akt, VEGF, ERBB2 pathways must be given consideration for understanding the role of HCQ and AZM in QT interval prolongation. Conclusion: Computational methods have certain limitations based on source database coverage and prediction algorithms and therefore this data needs experimental correlation to draw final conclusion, but current findings screen targets for QT interval prolongation associated with HCQ and AZM. These proteins and pathways may provide ways to reduce this major risk associated with this combination.


Subject(s)
Azithromycin/therapeutic use , COVID-19/drug therapy , Hydroxychloroquine/therapeutic use , Long QT Syndrome/etiology , Azithromycin/adverse effects , COVID-19/complications , COVID-19/epidemiology , Drug Combinations , HSP90 Heat-Shock Proteins/genetics , HSP90 Heat-Shock Proteins/metabolism , Humans , Hydroxychloroquine/adverse effects , Pandemics , Protein Interaction Maps , Proto-Oncogene Proteins c-akt/genetics , Proto-Oncogene Proteins c-akt/metabolism , SARS-CoV-2/drug effects , Signal Transduction/drug effects
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