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1.
Sci Immunol ; 6(60)2021 06 18.
Article in English | MEDLINE | ID: covidwho-1276879

ABSTRACT

The nutrient-sensing mammalian target of rapamycin (mTOR) is integral to cell fate decisions after T cell activation. Sustained mTORC1 activity favors the generation of terminally differentiated effector T cells instead of follicular helper and memory T cells. This is particularly pertinent for T cell responses of older adults who have sustained mTORC1 activation despite dysfunctional lysosomes. Here, we show that lysosome-deficient T cells rely on late endosomes rather than lysosomes as an mTORC1 activation platform, where mTORC1 is activated by sensing cytosolic amino acids. T cells from older adults have an increased expression of the plasma membrane leucine transporter SLC7A5 to provide a cytosolic amino acid source. Hence, SLC7A5 and VPS39 deficiency (a member of the HOPS complex promoting early to late endosome conversion) substantially reduced mTORC1 activities in T cells from older but not young individuals. Late endosomal mTORC1 is independent of the negative-feedback loop involving mTORC1-induced inactivation of the transcription factor TFEB that controls expression of lysosomal genes. The resulting sustained mTORC1 activation impaired lysosome function and prevented lysosomal degradation of PD-1 in CD4+ T cells from older adults, thereby inhibiting their proliferative responses. VPS39 silencing of human T cells improved their expansion to pertussis and to SARS-CoV-2 peptides in vitro. Furthermore, adoptive transfer of CD4+ Vps39-deficient LCMV-specific SMARTA cells improved germinal center responses, CD8+ memory T cell generation, and recall responses to infection. Thus, curtailing late endosomal mTORC1 activity is a promising strategy to enhance T cell immunity.


Subject(s)
CD4-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/immunology , COVID-19/immunology , Endosomes/metabolism , Mechanistic Target of Rapamycin Complex 1/metabolism , SARS-CoV-2/metabolism , Signal Transduction/genetics , Adoptive Transfer/methods , Adult , Aged , Aged, 80 and over , Animals , Autophagy-Related Proteins/deficiency , Autophagy-Related Proteins/genetics , Basic Helix-Loop-Helix Leucine Zipper Transcription Factors/genetics , Basic Helix-Loop-Helix Leucine Zipper Transcription Factors/metabolism , COVID-19/virology , Cells, Cultured , Female , Forkhead Box Protein O1/deficiency , Forkhead Box Protein O1/genetics , Healthy Volunteers , Humans , Large Neutral Amino Acid-Transporter 1/metabolism , Lysosomes/metabolism , Male , Mice , Mice, Inbred C57BL , Mice, Transgenic , Signal Transduction/immunology , Transfection , Vesicular Transport Proteins/deficiency , Vesicular Transport Proteins/genetics , Young Adult
2.
J Clin Invest ; 131(11)2021 06 01.
Article in English | MEDLINE | ID: covidwho-1249494

ABSTRACT

With increasing age, individuals are more vulnerable to viral infections such as with influenza or the SARS-CoV-2 virus. One age-associated defect in human T cells is the reduced expression of miR-181a. miR-181ab1 deficiency in peripheral murine T cells causes delayed viral clearance after infection, resembling human immune aging. Here we show that naive T cells from older individuals as well as miR-181ab1-deficient murine T cells develop excessive replication stress after activation, due to reduced histone expression and delayed S-phase cell cycle progression. Reduced histone expression was caused by the miR-181a target SIRT1 that directly repressed transcription of histone genes by binding to their promoters and reducing histone acetylation. Inhibition of SIRT1 activity or SIRT1 silencing increased histone expression, restored cell cycle progression, diminished the replication-stress response, and reduced the production of inflammatory mediators in replicating T cells from old individuals. Correspondingly, treatment with SIRT1 inhibitors improved viral clearance in mice with miR-181a-deficient T cells after LCMV infection. In conclusion, SIRT1 inhibition may be beneficial to treat systemic viral infection in older individuals by targeting antigen-specific T cells that develop replication stress due to miR-181a deficiency.


Subject(s)
COVID-19/immunology , Cellular Senescence/immunology , Histones/deficiency , MicroRNAs/immunology , SARS-CoV-2/immunology , T-Lymphocytes/immunology , Animals , COVID-19/genetics , Cellular Senescence/genetics , Female , Histones/immunology , Humans , Male , Mice, Knockout , MicroRNAs/genetics , SARS-CoV-2/genetics , Sirtuin 1/genetics , Sirtuin 1/immunology
3.
Biomed Pharmacother ; 137: 111313, 2021 May.
Article in English | MEDLINE | ID: covidwho-1062248

ABSTRACT

The SARS-CoV-2 outbreak and pandemic that began near the end of 2019 has posed a challenge to global health. At present, many candidate small-molecule therapeutics have been developed that can inhibit both the infection and replication of SARS-CoV-2 and even potentially relieve cytokine storms and other related complications. Meanwhile, host-targeted drugs that inhibit cellular transmembrane serine protease (TMPRSS2) can prevent SARS-CoV-2 from entering cells, and its combination with chloroquine and dihydroorotate dehydrogenase (DHODH) inhibitors can limit the spread of SARS-CoV-2 and reduce the morbidity and mortality of patients with COVID-19. The present article provides an overview of these small-molecule therapeutics based on insights from medicinal chemistry research and focuses on RNA-dependent RNA polymerase (RdRp) inhibitors, such as the nucleoside analogues remdesivir, favipiravir and ribavirin. This review also covers inhibitors of 3C-like protease (3CLpro), papain-like protease (PLpro) and other potentially innovative active ingredient molecules, describing their potential targets, activities, clinical status and side effects.


Subject(s)
Antiviral Agents , COVID-19 , Molecular Targeted Therapy/methods , SARS-CoV-2 , Antiviral Agents/classification , Antiviral Agents/pharmacology , COVID-19/drug therapy , COVID-19/metabolism , Enzyme Inhibitors/pharmacology , Humans , SARS-CoV-2/drug effects , SARS-CoV-2/enzymology , Therapies, Investigational
4.
Eur J Med Chem ; 213: 113201, 2021 Mar 05.
Article in English | MEDLINE | ID: covidwho-1039337

ABSTRACT

The widespread nature of several viruses is greatly credited to their rapidly altering RNA genomes that enable the infection to persist despite challenges presented by host cells. Within the RNA genome of infections is RNA-dependent RNA polymerase (RdRp), which is an essential enzyme that helps in RNA synthesis by catalysing the RNA template-dependent development of phosphodiester bonds. Therefore, RdRp is an important therapeutic target in RNA virus-caused diseases, including SARS-CoV-2. In this review, we describe the promising RdRp inhibitors that have been launched or are currently in clinical studies for the treatment of RNA virus infections. Structurally, nucleoside inhibitors (NIs) bind to the RdRp protein at the enzyme active site, and nonnucleoside inhibitors (NNIs) bind to the RdRp protein at allosteric sites. By reviewing these inhibitors, more precise guidelines for the development of more promising anti-RNA virus drugs should be set, and due to the current health emergency, they will eventually be used for COVID-19 treatment.


Subject(s)
Antiviral Agents/therapeutic use , COVID-19/drug therapy , Coronavirus RNA-Dependent RNA Polymerase/antagonists & inhibitors , Drug Repositioning , Enzyme Inhibitors/therapeutic use , Animals , Antiviral Agents/chemistry , COVID-19/epidemiology , Enzyme Inhibitors/chemistry , Humans , Nucleosides/chemistry , Nucleosides/therapeutic use , Pandemics , SARS-CoV-2/drug effects , SARS-CoV-2/enzymology
5.
Phytomed Plus ; 1(2): 100027, 2021 May.
Article in English | MEDLINE | ID: covidwho-1032443

ABSTRACT

Background: In December 2019, a novel coronavirus, SARS-CoV-2 caused a series of acute atypical respiratory diseases worldwide. However, there is still a lack of drugs with clear curative effects, and the clinical trial research of vaccines has not been completely finished. Purpose: LH capsules are approved TCM patent medicine that are widely used for the treatment of respiratory tract infectious diseases caused by colds and flu. On April 12, 2020, LH capsules and granules were officially repurposed by the China Food and Drug Administration (CFDA) for patients with mild COVID-19 based on their safety and efficacy demonstrated through multicentre, randomized, controlled clinical trials. We hope to conduct a comprehensive review of it through modern pharmacy methods, and try to explain its possible mechanism. Methods: Using the full names of LH capsules Lianhuaqingwen, Lianhua Qingwen andSARS-COV-2, COVID-19 as the keywords of the search terms, systemically search for existing related papers in various databases such as Web of Science and PubMed. And completed the collection of clinical data in ClinicalTrials.gov and Chinese Clinical Trial Registry. Last but not least, we have sorted out the anti-inflammatory and antiviral mechanisms of LH capsules through literature and Selleck. Results: This review systematically sorted out the active ingredients in LH capsules. Furthermore, the related pharmacological and clinical trials of LH capsule on SARS-CoV-2, IAV and IBV were discussed in detail. Moreover, the present review provides the first summary of the potential molecular mechanism of specific substances in LH capsules involved in resistance to SARS-COV-2 infection and the inhibition of cytokine storm syndrome (CSS) caused by IL-6. Conclusion: This review summarizes the available reports and evidence that support the use of LH capsules as potential drug candidates for the prevention and treatment of COVID-19. However, TCM exerts its effects through multiple targets and multiple pathways, and LH capsules are not an exception. Therefore, the relevant mechanisms need to be further improved and experimentally verified.

6.
Eur J Med Chem ; 206: 112711, 2020 Nov 15.
Article in English | MEDLINE | ID: covidwho-879739

ABSTRACT

This review fully describes the coronavirus 3CLpro peptidomimetic inhibitors and nonpeptidic small molecule inhibitors developed from 2010 to 2020. Specifically, the structural characteristics, binding modes and SARs of these 3CLpro inhibitors are expounded in detail by division into two categories: peptidomimetic inhibitors mainly utilize electrophilic warhead groups to covalently bind the 3CLpro Cys145 residue and thereby achieve irreversible inhibition effects, whereas nonpeptidic small molecule inhibitors mainly interact with residues in the S1', S1, S2 and S4 pockets via hydrogen bonds, hydrophobic bonds and van der Waals forces. Based on the emerging PROTAC technology and the existing 3CLpro inhibitors, 3CLpro PROTAC degraders are hypothesised to be next-generation anti-coronavirus drugs.


Subject(s)
Antiviral Agents/pharmacology , Protease Inhibitors/pharmacology , Viral Nonstructural Proteins/antagonists & inhibitors , Antiviral Agents/therapeutic use , Coronavirus 3C Proteases , Cysteine Endopeptidases , Humans , Peptidomimetics , Protease Inhibitors/therapeutic use
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