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FASEB J ; 35(9): e21870, 2021 09.
Article in English | MEDLINE | ID: covidwho-1373669


COVID-19 is often characterized by dysregulated inflammatory and immune responses. It has been shown that the Traditional Chinese Medicine formulation Qing-Fei-Pai-Du decoction (QFPDD) is effective in the treatment of the disease, especially for patients in the early stage. Our network pharmacology analyses indicated that many inflammation and immune-related molecules were the targets of the active components of QFPDD, which propelled us to examine the effects of the decoction on inflammation. We found in the present study that QFPDD effectively alleviated dextran sulfate sodium-induced intestinal inflammation in mice. It inhibited the production of pro-inflammatory cytokines IL-6 and TNFα, and promoted the expression of anti-inflammatory cytokine IL-10 by macrophagic cells. Further investigations found that QFPDD and one of its active components wogonoside markedly reduced LPS-stimulated phosphorylation of transcription factor ATF2, an important regulator of multiple cytokines expression. Our data revealed that both QFPDD and wogonoside decreased the half-life of ATF2 and promoted its proteasomal degradation. Of note, QFPDD and wogonoside down-regulated deubiquitinating enzyme USP14 along with inducing ATF2 degradation. Inhibition of USP14 with the small molecular inhibitor IU1 also led to the decrease of ATF2 in the cells, indicating that QFPDD and wogonoside may act through regulating USP14 to promote ATF2 degradation. To further assess the importance of ubiquitination in regulating ATF2, we generated mice that were intestinal-specific KLHL5 deficiency, a CUL3-interacting protein participating in substrate recognition of E3s. In these mice, QFPDD mitigated inflammatory reaction in the spleen, but not intestinal inflammation, suggesting CUL3-KLHL5 may function as an E3 for ATF2 degradation.

Activating Transcription Factor 2/metabolism , Down-Regulation/drug effects , Drugs, Chinese Herbal/pharmacology , Flavanones/pharmacology , Glucosides/pharmacology , Inflammation/drug therapy , Proteolysis/drug effects , Ubiquitin Thiolesterase/deficiency , Animals , Cell Line , Colitis/chemically induced , Colitis/drug therapy , Cullin Proteins/metabolism , Cytokines/metabolism , Dextran Sulfate/pharmacology , Dextran Sulfate/therapeutic use , Drugs, Chinese Herbal/therapeutic use , Flavanones/therapeutic use , Glucosides/therapeutic use , Inflammation/chemically induced , Macrophages/drug effects , Macrophages/metabolism , Male , Mice , Mice, Inbred C57BL , Phosphorylation/drug effects , Proteasome Endopeptidase Complex/drug effects , Proteasome Endopeptidase Complex/metabolism , Pyrroles/pharmacology , Pyrrolidines/pharmacology , Ubiquitin Thiolesterase/antagonists & inhibitors , Ubiquitination
Comput Biol Chem ; 89: 107376, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-753733


Human ubiquitin carboxyl-terminal hydrolase-2 (USP2) inhibitors, such as thiopurine analogs, have been reported to inhibit SARS-CoV papain-like proteases (PLpro). The PLpro have significant functional implications in the innate immune response during SARS-CoV-2 infection and considered an important antiviral target. Both proteases share strikingly similar USP fold with right-handed thumb-palm-fingers structural scaffold and conserved catalytic triad Cys-His-Asp/Asn. In this urgency situation of COVID-19 outbreak, there is a lack of in-vitro facilities readily available to test SARS-CoV-2 inhibitors in whole-cell assays. Therefore, we adopted an alternate route to identify potential USP2 inhibitor through integrated in-silico efforts. After an extensive virtual screening protocol, the best compounds were selected and tested. The compound Z93 showed significant IC50 value against Jurkat (9.67 µM) and MOTL-4 cells (11.8 µM). The binding mode of Z93 was extensively analyzed through molecular docking, followed by MD simulations, and molecular interactions were compared with SARS-CoV-2. The relative binding poses of Z93 fitted well in the binding site of both proteases and showed consensus π-π stacking and H-bond interactions with histidine and aspartate/asparagine residues of the catalytic triad. These results led us to speculate that compound Z93 might be the first potential chemical lead against SARS-CoV-2 PLpro, which warrants in-vitro evaluations.

Antiviral Agents/pharmacology , COVID-19/drug therapy , Coronavirus 3C Proteases/antagonists & inhibitors , Coronavirus Protease Inhibitors/pharmacology , SARS-CoV-2/drug effects , SARS-CoV-2/enzymology , Ubiquitin Thiolesterase/antagonists & inhibitors , Antiviral Agents/chemistry , COVID-19/virology , Cell Line, Tumor , Coronavirus 3C Proteases/metabolism , Coronavirus Protease Inhibitors/chemistry , Drug Evaluation, Preclinical , Humans , Jurkat Cells , Models, Molecular , Molecular Structure , Ubiquitin Thiolesterase/metabolism