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1.
Front Immunol ; 12: 789735, 2021.
Article in English | MEDLINE | ID: covidwho-1581322

ABSTRACT

Background: The host immune response has a prominent role in the progression and outcome of SARS-CoV-2 infection. Lymphopenia has been described as an important feature of SARS-CoV-2 infection and has been associated with severe disease manifestation. Lymphocyte dysregulation and hyper-inflammation have been shown to be associated with a more severe clinical course; however, a T cell subpopulation whose dysfunction correlate with disease progression has yet to be identify. Methods: We performed an immuno-phenotypic analysis of T cell sub-populations in peripheral blood from patients affected by different severity of COVID-19 (n=60) and undergoing a different clinical evolution. Clinical severity was established based on a modified WHO score considering both ventilation support and respiratory capacity (PaO2/FiO2 ratio). The ability of circulating cells at baseline to predict the probability of clinical aggravation was explored through multivariate regression analyses. Results: The immuno-phenotypic analysis performed by multi-colour flow cytometry confirmed that patients suffering from severe COVID-19 harboured significantly reduced circulating T cell subsets, especially for CD4+ T, Th1, and regulatory T cells. Peripheral T cells also correlated with parameters associated with disease severity, i.e., PaO2/FiO2 ratio and inflammation markers. CD4+ T cell subsets showed an important significant association with clinical evolution, with patients presenting markedly decreased regulatory T cells at baseline having a significantly higher risk of aggravation. Importantly, the combination of gender and regulatory T cells allowed distinguishing between improved and worsened patients with an area under the ROC curve (AUC) of 82%. Conclusions: The present study demonstrates the association between CD4+ T cell dysregulation and COVID-19 severity and progression. Our results support the importance of analysing baseline regulatory T cell levels, since they were revealed able to predict the clinical worsening during hospitalization. Regulatory T cells assessment soon after hospital admission could thus allow a better clinical stratification and patient management.


Subject(s)
COVID-19/epidemiology , COVID-19/immunology , Hospitalization , Lymphocyte Count , SARS-CoV-2/immunology , T-Lymphocytes, Regulatory/immunology , Biomarkers , COVID-19/diagnosis , COVID-19/virology , COVID-19 Serological Testing , Cytokines/blood , Cytokines/metabolism , Disease Progression , Humans , Immunophenotyping , Inflammation Mediators/blood , Inflammation Mediators/metabolism , Prognosis , Public Health Surveillance , ROC Curve , Severity of Illness Index , T-Lymphocyte Subsets/immunology , T-Lymphocyte Subsets/metabolism , T-Lymphocytes, Regulatory/metabolism
2.
Biomed Pharmacother ; 144: 112230, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1517059

ABSTRACT

The COVID-19 pandemic caused by the coronavirus SARS-CoV-2 has become a serious challenge for medicine and science. Analysis of the molecular mechanisms associated with the clinical manifestations and severity of COVID-19 has identified several key points of immune dysregulation observed in SARS-CoV-2 infection. For diabetic patients, factors including higher binding affinity and virus penetration, decreased virus clearance and decreased T cell function, increased susceptibility to hyperinflammation, and cytokine storm may make these patients susceptible to a more severe course of COVID-19 disease. Metabolic changes induced by diabetes, especially hyperglycemia, can directly affect the immunometabolism of lymphocytes in part by affecting the activity of the mTOR protein kinase signaling pathway. High mTOR activity can enhance the progression of diabetes due to the activation of effector proinflammatory subpopulations of lymphocytes and, conversely, low activity promotes the differentiation of T-regulatory cells. Interestingly, metformin, an extensively used antidiabetic drug, inhibits mTOR by affecting the activity of AMPK. Therefore, activation of AMPK and/or inhibition of the mTOR-mediated signaling pathway may be an important new target for drug therapy in COVID-19 cases mostly by reducing the level of pro-inflammatory signaling and cytokine storm. These suggestions have been partially confirmed by several retrospective analyzes of patients with diabetes mellitus hospitalized for severe COVID-19.


Subject(s)
COVID-19/drug therapy , Diabetes Mellitus/drug therapy , Hypoglycemic Agents/therapeutic use , Immunity, Cellular/drug effects , Metformin/therapeutic use , Severity of Illness Index , COVID-19/epidemiology , COVID-19/immunology , COVID-19/metabolism , Diabetes Mellitus/epidemiology , Diabetes Mellitus/immunology , Diabetes Mellitus/metabolism , Humans , Hypoglycemic Agents/pharmacology , Immunity, Cellular/physiology , Lymphocytes/drug effects , Lymphocytes/immunology , Lymphocytes/metabolism , Metformin/pharmacology , Mortality/trends , T-Lymphocytes, Regulatory/drug effects , T-Lymphocytes, Regulatory/immunology , T-Lymphocytes, Regulatory/metabolism , TOR Serine-Threonine Kinases/antagonists & inhibitors , TOR Serine-Threonine Kinases/immunology , TOR Serine-Threonine Kinases/metabolism
3.
Cell Signal ; 87: 110121, 2021 11.
Article in English | MEDLINE | ID: covidwho-1370457

ABSTRACT

The SARS-CoV-2 virus has caused a worldwide COVID-19 pandemic. In less than a year and a half, more than 200 million people have been infected and more than four million have died. Despite some improvement in the treatment strategies, no definitive treatment protocol has been developed. The pathogenesis of the disease has not been clearly elucidated yet. A clear understanding of its pathogenesis will help develop effective vaccines and drugs. The immunopathogenesis of COVID-19 is characteristic with acute respiratory distress syndrome and multiorgan involvement with impaired Type I interferon response and hyperinflammation. The destructive systemic effects of COVID-19 cannot be explained simply by the viral tropism through the ACE2 and TMPRSS2 receptors. In addition, the recently identified mutations cannot fully explain the defect in all cases of Type I interferon synthesis. We hypothesize that retinol depletion and resulting impaired retinoid signaling play a central role in the COVID-19 pathogenesis that is characteristic for dysregulated immune system, defect in Type I interferon synthesis, severe inflammatory process, and destructive systemic multiorgan involvement. Viral RNA recognition mechanism through RIG-I receptors can quickly consume a large amount of the body's retinoid reserve, which causes the retinol levels to fall below the normal serum levels. This causes retinoid insufficiency and impaired retinoid signaling, which leads to interruption in Type I interferon synthesis and an excessive inflammation. Therefore, reconstitution of the retinoid signaling may prove to be a valid strategy for management of COVID-19 as well for some other chronic, degenerative, inflammatory, and autoimmune diseases.


Subject(s)
COVID-19/pathology , Signal Transduction/physiology , Vitamin A/metabolism , COVID-19/immunology , COVID-19/metabolism , COVID-19/virology , Central Nervous System/metabolism , DEAD Box Protein 58/metabolism , Humans , Immune Tolerance , Interferon Type I/metabolism , Receptors, Immunologic/metabolism , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification , T-Lymphocytes, Regulatory/immunology , T-Lymphocytes, Regulatory/metabolism , Viral Tropism/physiology , Vitamin A/blood
4.
Front Immunol ; 12: 655122, 2021.
Article in English | MEDLINE | ID: covidwho-1365539

ABSTRACT

FOXP3+ regulatory T cells (Tregs) are central for maintaining peripheral tolerance and immune homeostasis. Because of their immunosuppressive characteristics, Tregs are a potential therapeutic target in various diseases such as autoimmunity, transplantation and infectious diseases like COVID-19. Numerous studies are currently exploring the potential of adoptive Treg therapy in different disease settings and novel genome editing techniques like CRISPR/Cas will likely widen possibilities to strengthen its efficacy. However, robust and expeditious protocols for genome editing of human Tregs are limited. Here, we describe a rapid and effective protocol for reaching high genome editing efficiencies in human Tregs without compromising cell integrity, suitable for potential therapeutic applications. By deletion of IL2RA encoding for IL-2 receptor α-chain (CD25) in Tregs, we demonstrated the applicability of the method for downstream functional assays and highlighted the importance for CD25 for in vitro suppressive function of human Tregs. Moreover, deletion of IL6RA (CD126) in human Tregs elicits cytokine unresponsiveness and thus may prevent IL-6-mediated instability of Tregs, making it an attractive target to potentially boost functionality in settings of adoptive Treg therapies to contain overreaching inflammation or autoimmunity. Thus, our rapid and efficient protocol for genome editing in human Tregs may advance possibilities for Treg-based cellular therapies.


Subject(s)
Gene Editing/methods , Interleukin-2 Receptor alpha Subunit/genetics , Receptors, Interleukin-6/genetics , T-Lymphocytes, Regulatory/metabolism , Blood Buffy Coat/cytology , CRISPR-Cas Systems/genetics , Forkhead Transcription Factors/metabolism , Gene Knockdown Techniques , HEK293 Cells , Healthy Volunteers , Humans , Immunotherapy, Adoptive/methods , Primary Cell Culture , RNA, Guide/genetics , Time Factors
5.
Int Immunopharmacol ; 97: 107828, 2021 Aug.
Article in English | MEDLINE | ID: covidwho-1253058

ABSTRACT

In various pathological conditions, cellular immunity plays an important role in immune responses. Amongimmunecells, T lymphocytes pdomotecellular and humoralresponses as well as innate immunity. Therefore, careful investigation of these cells has a significant impact on accurate knowledge in COVID-19diseasepathogenesis. In current research, the frequency and function of various T lymphocytes involved in immune responses examined in SARS-CoV-2 patients with various disease severity compared to normal subjects. In order to make an accurate comparison among patients with various disease severity, this study was performed on asymptomatic recovered cases (n = 20), ICU hospitalized patients (n = 30), non-ICU hospitalized patients (n = 30), and normal subjects (n = 20). To precisely evaluate T cells activity following purification, their cytokine secretion activity was examined. Similarly, immediately after purification of Treg cells, their inhibitory activity on T cells was investigated. The results showed that COVID-19 patients with severe disease (ICU hospitalized patients) not only had a remarkable increase in Th1 and Th17 but also a considerable decrease in Th2 and Treg cells. More importantly, as the IL-17 and IFN-γ secretion was sharply increased in severe disease, the secretion of IL-10 and IL-4 was decreased. Furthermore, the inhibitory activity of Treg cells was reduced in severe disease patients in comparison to other groups. In severe COVID-19 disease, current findings indicate when the inflammatory arm of cellular immunity is significantly increased, a considerable reduction in anti-inflammatory and regulatory arm occurred.


Subject(s)
COVID-19/blood , COVID-19/immunology , T-Lymphocyte Subsets/immunology , T-Lymphocyte Subsets/virology , Adult , Aged , Cytokines/immunology , Cytokines/metabolism , Female , Healthy Volunteers , Humans , Immunity, Cellular , Inflammation/metabolism , Interferon-gamma/metabolism , Interleukin-10/metabolism , Interleukin-17/metabolism , Interleukin-4/metabolism , Leukocytes/immunology , Leukocytes/metabolism , Male , Middle Aged , Severity of Illness Index , T-Lymphocyte Subsets/metabolism , T-Lymphocytes, Regulatory/immunology , T-Lymphocytes, Regulatory/metabolism , Th1 Cells/immunology , Th1 Cells/metabolism , Th17 Cells/immunology , Th17 Cells/metabolism , Th2 Cells/immunology , Th2 Cells/metabolism , Young Adult
6.
Immunity ; 54(6): 1186-1199.e7, 2021 06 08.
Article in English | MEDLINE | ID: covidwho-1207036

ABSTRACT

A cardinal feature of COVID-19 is lung inflammation and respiratory failure. In a prospective multi-country cohort of COVID-19 patients, we found that increased Notch4 expression on circulating regulatory T (Treg) cells was associated with disease severity, predicted mortality, and declined upon recovery. Deletion of Notch4 in Treg cells or therapy with anti-Notch4 antibodies in conventional and humanized mice normalized the dysregulated innate immunity and rescued disease morbidity and mortality induced by a synthetic analog of viral RNA or by influenza H1N1 virus. Mechanistically, Notch4 suppressed the induction by interleukin-18 of amphiregulin, a cytokine necessary for tissue repair. Protection by Notch4 inhibition was recapitulated by therapy with Amphiregulin and, reciprocally, abrogated by its antagonism. Amphiregulin declined in COVID-19 subjects as a function of disease severity and Notch4 expression. Thus, Notch4 expression on Treg cells dynamically restrains amphiregulin-dependent tissue repair to promote severe lung inflammation, with therapeutic implications for COVID-19 and related infections.


Subject(s)
Host-Pathogen Interactions , Immunity, Cellular , Pneumonia, Viral/etiology , Pneumonia, Viral/metabolism , Receptor, Notch4/metabolism , Signal Transduction , T-Lymphocytes, Regulatory/immunology , T-Lymphocytes, Regulatory/metabolism , Amphiregulin/pharmacology , Animals , Biomarkers , Cytokines/metabolism , Disease Models, Animal , Disease Susceptibility , Host-Pathogen Interactions/immunology , Humans , Immunohistochemistry , Immunomodulation/drug effects , Inflammation Mediators/metabolism , Influenza A virus/physiology , Lung/immunology , Lung/metabolism , Lung/pathology , Lung/virology , Mice , Mice, Transgenic , Pneumonia, Viral/pathology , Receptor, Notch4/antagonists & inhibitors , Receptor, Notch4/genetics , Severity of Illness Index
7.
J Leukoc Biol ; 109(1): 91-97, 2021 01.
Article in English | MEDLINE | ID: covidwho-1188013

ABSTRACT

Regulatory T cell can protect against severe forms of coronaviral infections attributable to host inflammatory responses. But its role in the pathogenesis of COVID-19 is still unclear. In this study, frequencies of total and multiple subsets of lymphocytes in peripheral blood of COVID-19 patients and discharged individuals were analyzed using a multicolor flow cytometry assay. Plasma concentration of IL-10 was measured using a microsphere-based immunoassay kit. Comparing to healthy controls, the frequencies of total lymphocytes and T cells decreased significantly in both acutely infected COVID-19 patients and discharged individuals. The frequencies of total lymphocytes correlated negatively with the frequencies of CD3- CD56+ NK cells. The frequencies of regulatory CD8+ CD25+ T cells correlated with CD4+ /CD8+ T cell ratios positively, while the frequencies of regulatory CD4+ CD25+ CD127- T cells correlated negatively with CD4+ /CD8+ T cell ratios. Ratios of CD4+ /CD8+ T cells increased significantly in patients beyond age of 45 years. And accordingly, the frequencies of regulatory CD8+ CD25+ T cells were also found significantly increased in these patients. Collectively, the results suggest that regulatory CD4+ and CD8+ T cells may play distinct roles in the pathogenesis of COVID-19. Moreover, the data indicate that NK cells might contribute to the COVID-19 associated lymphopenia.


Subject(s)
CD8-Positive T-Lymphocytes , COVID-19 , SARS-CoV-2 , T-Lymphocytes, Regulatory , Adult , Aged , Antigens, CD/blood , Antigens, CD/immunology , CD4-CD8 Ratio , CD8-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/metabolism , CD8-Positive T-Lymphocytes/pathology , COVID-19/blood , COVID-19/immunology , COVID-19/pathology , Female , Humans , Killer Cells, Natural/immunology , Killer Cells, Natural/pathology , Male , Middle Aged , SARS-CoV-2/immunology , SARS-CoV-2/metabolism , T-Lymphocytes, Regulatory/immunology , T-Lymphocytes, Regulatory/metabolism , T-Lymphocytes, Regulatory/pathology
8.
Cell Immunol ; 364: 104347, 2021 06.
Article in English | MEDLINE | ID: covidwho-1157177

ABSTRACT

Myeloid-derived suppressor cells (MDSC) are important immune-regulatory cells but their identification remains difficult. Here, we provide a critical view on selected surface markers, transcriptional and translational pathways commonly used to identify MDSC by specific, their developmental origin and new possibilities by transcriptional or proteomic profiling. Discrimination of MDSC from their non-suppressive counterparts is a prerequisite for the development of successful therapies. Understanding the switch mechanisms that direct granulocytic and monocytic development into a pro-inflammatory or anti-inflammatory direction will be crucial for therapeutic strategies. Manipulation of these myeloid checkpoints are exploited by tumors and pathogens, such as M. tuberculosis (Mtb), HIV or SARS-CoV-2, that induce MDSC for immune evasion. Thus, specific markers for MDSC identification may reveal also novel molecular candidates for therapeutic intervention at the level of MDSC.


Subject(s)
Biomarkers/metabolism , Gene Expression Profiling/methods , Myeloid-Derived Suppressor Cells/immunology , Proteomics/methods , Signal Transduction/immunology , Animals , B7-H1 Antigen/genetics , B7-H1 Antigen/immunology , B7-H1 Antigen/metabolism , COVID-19/immunology , COVID-19/prevention & control , COVID-19/virology , Cells, Cultured , Humans , Mice , Myeloid-Derived Suppressor Cells/metabolism , Neoplasms/genetics , Neoplasms/immunology , Neoplasms/metabolism , Programmed Cell Death 1 Receptor/genetics , Programmed Cell Death 1 Receptor/immunology , Programmed Cell Death 1 Receptor/metabolism , SARS-CoV-2/immunology , SARS-CoV-2/isolation & purification , SARS-CoV-2/physiology , Signal Transduction/genetics , T-Lymphocytes, Regulatory/immunology , T-Lymphocytes, Regulatory/metabolism
9.
JCI Insight ; 6(6)2021 03 22.
Article in English | MEDLINE | ID: covidwho-1088356

ABSTRACT

Regulatory T (Treg) cells orchestrate resolution and repair of acute lung inflammation and injury after viral pneumonia. Compared with younger patients, older individuals experience impaired recovery and worse clinical outcomes after severe viral infections, including influenza and SARS coronavirus 2 (SARS-CoV-2). Whether age is a key determinant of Treg cell prorepair function after lung injury remains unknown. Here, we showed that aging results in a cell-autonomous impairment of reparative Treg cell function after experimental influenza pneumonia. Transcriptional and DNA methylation profiling of sorted Treg cells provided insight into the mechanisms underlying their age-related dysfunction, with Treg cells from aged mice demonstrating both loss of reparative programs and gain of maladaptive programs. Strategies to restore youthful Treg cell functional programs could be leveraged as therapies to improve outcomes among older individuals with severe viral pneumonia.


Subject(s)
Aging/physiology , Influenza A virus , Influenza, Human/pathology , Lung/pathology , Pneumonia, Viral/pathology , SARS-CoV-2 , T-Lymphocytes, Regulatory/pathology , Age Factors , Aging/metabolism , Animals , COVID-19/complications , COVID-19/metabolism , COVID-19/pathology , COVID-19/virology , Humans , Influenza, Human/complications , Influenza, Human/metabolism , Influenza, Human/virology , Lung/metabolism , Mice, Inbred C57BL , Pneumonia, Viral/etiology , Pneumonia, Viral/metabolism , Pneumonia, Viral/virology , T-Lymphocytes, Regulatory/metabolism
10.
J Cell Physiol ; 236(7): 5325-5338, 2021 07.
Article in English | MEDLINE | ID: covidwho-995973

ABSTRACT

In novel coronavirus disease 2019 (COVID-19), the increased frequency and overactivation of T helper (Th) 17 cells and subsequent production of large amounts of proinflammatory cytokines result in hyperinflammation and disease progression. The current study aimed to investigate the therapeutic effects of nanocurcumin on the frequency and responses of Th17 cells in mild and severe COVID-19 patients. In this study, 40 severe COVID-19 intensive care unit-admitted patients and 40 patients in mild condition were included. The frequency of Th17 cells, the messenger RNA expression of Th17 cell-related factors (RAR-related orphan receptor γt, interleukin [IL]-17, IL-21, IL-23, and granulocyte-macrophage colony-stimulating factor), and the serum levels of cytokines were measured in both nanocurcumin and placebo-treated groups before and after treatment. A significant decrease in the number of Th17 cells, downregulation of Th17 cell-related factors, and decreased levels of Th17 cell-related cytokines were found in mild and severe COVID-19 patients treated by nanocurcumin compared to the placebo group. Moreover, the abovementioned parameters were significantly decreased in the nanocurcumin-treated group after treatment versus before treatment. Curcumin could reduce the frequency of Th17 cells and their related inflammatory factors in both mild and severe COVID-19 patients. Hence, it could be considered as a potential modulatory compound in improving the patient's inflammatory condition.


Subject(s)
COVID-19/drug therapy , Curcumin/therapeutic use , Immunomodulation/drug effects , Nanoparticles/therapeutic use , Th17 Cells/drug effects , Adult , Cytokines/metabolism , Female , Granulocyte-Macrophage Colony-Stimulating Factor/metabolism , Humans , Male , Middle Aged , Nanoparticles/administration & dosage , SARS-CoV-2/drug effects , Severity of Illness Index , T-Lymphocytes, Regulatory/drug effects , T-Lymphocytes, Regulatory/metabolism , T-Lymphocytes, Regulatory/virology , Th17 Cells/metabolism
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