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1.
BMC Infect Dis ; 22(1): 448, 2022 May 10.
Article in English | MEDLINE | ID: covidwho-1833287

ABSTRACT

BACKGROUND: The etiopathogenesis of coronavirus disease 2019 (COVID-19) stem partially from the abnormal activation of the innate and adaptive immune systems. Here in the current investigation, the mRNA expression levels of toll-like receptors (TLRs) were evaluated in the nasopharyngeal epithelial cells from COVID-19 patients. METHODS: Epithelial cells were obtained using nasopharyngeal swab samples from 90 COVID-19 patients and 50 controls. COVID-19 cases were classified into those without symptoms, with symptoms but not hospitalized, and with symptoms and hospitalized. To determine the mRNA expression levels of TLRs, first RNA was extracted and cDNA was synthesized, and finally Real-time PCR was exerted. RESULTS: It was seen that the transcript levels of TLR3, TLR7, TLR8, and TLR9 were overexpressed in the COVID-19 patients with clinical symptoms needing hospitalization as well as in those with clinical symptoms without needing for hospitalization compared to controls. Upregulation of TLRs was associated with clinical presentations of the patients. CONCLUSIONS: Modulation of TLR3, TLR7, TLR8, TLR9 in the epithelial cells of COVID-19 cases may estimate the disease severity and requirement for hospitalization.


Subject(s)
COVID-19 , Toll-Like Receptor 3 , Epithelial Cells/metabolism , Humans , Nasopharynx , RNA, Messenger/genetics , Toll-Like Receptor 3/genetics , Toll-Like Receptor 3/metabolism , Toll-Like Receptor 7/genetics , Toll-Like Receptor 8/genetics , Toll-Like Receptor 9/genetics , Toll-Like Receptors/genetics
2.
Front Cell Infect Microbiol ; 12: 865283, 2022.
Article in English | MEDLINE | ID: covidwho-1822357

ABSTRACT

Nephropathogenic infectious bronchitis virus (NIBV) is one of the most important viral pathogens in the world poultry industry. Here, we used RT-qPCR, WB and immunofluorescence to explore the interaction between NIBV and the host innate immune system of the kidney. Multiple virions were found in the kidney tissues of the disease group under electron microscopy, and pathological changes such as structural damage of renal tubules and bleeding were observed by HE staining. In addition, we found that the mRNA levels of TLR7, TRAF6, and IKKß were upregulated after NIBV infection. IRF7 mRNA levels decreased significantly at 5 dpi and increased significantly at 11 to 18 dpi. The NF-κB P65 mRNA level increased significantly at 5 to 18 dpi and decreased at 28 dpi. However, NIBV infection-induced NF-κB P65 protein levels were downregulated at multiple time points. Moreover, we demonstrated that the cytokine (IFN-γ, IL-8, and IL-6) mRNA and protein expression levels were increased significantly at multiple time points after NIBV infection. Furthermore, immunofluorescence analysis showed that NF-κB P65 and IFN-γ were mainly located in the nuclear or perinuclear region. The positive signal intensity of NF-κB P65 was significantly lower than that of the normal group at 1 to 5 dpi, and there was no significant change in the subsequent time period. The positive signal intensity of IFN-γ decreased significantly at 5 dpi, and increased significantly at 11 to 28 dpi. In conclusion, we found that NIBV promoted cytokine release through the TLR7/NF-κB signaling axis, thus causing kidney injury.


Subject(s)
Infectious bronchitis virus , Animals , Chickens , Cytokines/metabolism , Infectious bronchitis virus/metabolism , Kidney/pathology , NF-kappa B/metabolism , RNA, Messenger/metabolism , Toll-Like Receptor 7/genetics
3.
Nature ; 603(7902): 587-598, 2022 03.
Article in English | MEDLINE | ID: covidwho-1655590

ABSTRACT

SARS-CoV-2 infection is benign in most individuals but, in around 10% of cases, it triggers hypoxaemic COVID-19 pneumonia, which leads to critical illness in around 3% of cases. The ensuing risk of death (approximately 1% across age and gender) doubles every five years from childhood onwards and is around 1.5 times greater in men than in women. Here we review the molecular and cellular determinants of critical COVID-19 pneumonia. Inborn errors of type I interferons (IFNs), including autosomal TLR3 and X-chromosome-linked TLR7 deficiencies, are found in around 1-5% of patients with critical pneumonia under 60 years old, and a lower proportion in older patients. Pre-existing auto-antibodies neutralizing IFNα, IFNß and/or IFNω, which are more common in men than in women, are found in approximately 15-20% of patients with critical pneumonia over 70 years old, and a lower proportion in younger patients. Thus, at least 15% of cases of critical COVID-19 pneumonia can be explained. The TLR3- and TLR7-dependent production of type I IFNs by respiratory epithelial cells and plasmacytoid dendritic cells, respectively, is essential for host defence against SARS-CoV-2. In ways that can depend on age and sex, insufficient type I IFN immunity in the respiratory tract during the first few days of infection may account for the spread of the virus, leading to pulmonary and systemic inflammation.


Subject(s)
COVID-19/genetics , COVID-19/immunology , Interferon Type I/immunology , Age Distribution , Autoantibodies/immunology , COVID-19/mortality , COVID-19/pathology , Critical Illness , Dendritic Cells/immunology , Genome-Wide Association Study , Humans , Interferon Type I/genetics , Sex Distribution , Toll-Like Receptor 3/deficiency , Toll-Like Receptor 7/deficiency , Toll-Like Receptor 7/genetics
4.
Clin Immunol ; 235: 108929, 2022 02.
Article in English | MEDLINE | ID: covidwho-1629722

ABSTRACT

Toll-like receptor 3 (TLR3) and TLR7 genes are involved in the host immune response against viral infections including SARS-COV-2. This study aimed to investigate the association between the TLR3(rs3775290) and TLR7(rs179008) polymorphisms with the prognosis and susceptibility to COVID-19 pneumonia accompanying SARS-COV-2 infection. This case-control study included 236 individuals: 136 COVID-19 pneumonia patients and 100 age and sex-matched controls. Two polymorphisms (TLR3 rs3775290 and TLR7 rs179008) were genotyped by allelic discrimination through TaqMan real-time PCR. This study also investigated predictors of mortality in COVID-19 pneumonia through logistic regression. The mutant 'T/T' genotypes and the 'T' alleles of TLR3(rs3775290) and TLR7(rs179008) polymorphisms were significantly associated with increased risk of COVID-19 pneumonia. This study did not report association between the mutant 'T/T' genotypes of TLR3(rs3775290) and TLR7(rs179008) and the disease outcome. In multivariate analysis, the independent predictors of mortality in COVID-19 pneumonia were male sex, SPO2 ≤ 82%, INR > 1, LDH ≥ 1000 U/l, and lymphocyte count<900/mm3 (P < 0.05).


Subject(s)
COVID-19/genetics , Genetic Predisposition to Disease/genetics , Pneumonia/genetics , Polymorphism, Single Nucleotide , Toll-Like Receptor 3/genetics , Toll-Like Receptor 7/genetics , Aged , Alleles , COVID-19/diagnosis , COVID-19/virology , Case-Control Studies , Female , Gene Frequency , Genotype , Humans , Male , Middle Aged , Pneumonia/diagnosis , Pneumonia/virology , Prognosis , ROC Curve , Risk Factors , SARS-CoV-2/physiology
5.
Genes Immun ; 23(1): 51-56, 2022 02.
Article in English | MEDLINE | ID: covidwho-1585868

ABSTRACT

Toll-like receptors (TLR) are crucial components in the initiation of innate immune responses to a variety of pathogens, triggering the production of pro-inflammatory cytokines and type I and II interferons, which are responsible for innate antiviral responses. Among the different TLRs, TLR7 recognizes several single-stranded RNA viruses including SARS-CoV-2. We and others identified rare loss-of-function variants in X-chromosomal TLR7 in young men with severe COVID-19 and with no prior history of major chronic diseases, that were associated with impaired TLR7 signaling as well as type I and II IFN responses. Here, we performed RNA sequencing to investigate transcriptome variations following imiquimod stimulation of peripheral blood mononuclear cells isolated from patients carrying previously identified hypomorphic, hypofunctional, and loss-of-function TLR7 variants. Our investigation revealed a profound impairment of the TLR7 pathway in patients carrying loss-of-function variants. Of note, a failure in IFNγ upregulation following stimulation was also observed in cells harboring the hypofunctional and hypomorphic variants. We also identified new TLR7 variants in severely affected male patients for which a functional characterization of the TLR7 pathway was performed demonstrating a decrease in mRNA levels in the IFNα, IFNγ, RSAD2, ACOD1, IFIT2, and CXCL10 genes.


Subject(s)
COVID-19 , Toll-Like Receptor 7 , Cytokines/metabolism , Down-Regulation , Humans , Leukocytes, Mononuclear/metabolism , Male , SARS-CoV-2 , Toll-Like Receptor 7/genetics , Toll-Like Receptor 7/metabolism , Toll-Like Receptor 8/genetics , Toll-Like Receptor 8/metabolism
6.
Front Immunol ; 12: 756262, 2021.
Article in English | MEDLINE | ID: covidwho-1551507

ABSTRACT

A male sex bias has emerged in the COVID-19 pandemic, fitting to the sex-biased pattern in other viral infections. Males are 2.84 times more often admitted to the ICU and mortality is 1.39 times higher as a result of COVID-19. Various factors play a role in this, and novel studies suggest that the gene-dose of Toll-Like Receptor (TLR) 7 could contribute to the sex-skewed severity. TLR7 is one of the crucial pattern recognition receptors for SARS-CoV-2 ssRNA and the gene-dose effect is caused by X chromosome inactivation (XCI) escape. Female immune cells with TLR7 XCI escape have biallelic TLR7 expression and produce more type 1 interferon (IFN) upon TLR7 stimulation. In COVID-19, TLR7 in plasmacytoid dendritic cells is one of the pattern recognition receptors responsible for IFN production and a delayed IFN response has been associated with immunopathogenesis and mortality. Here, we provide a hypothesis that females may be protected to some extend against severe COVID-19, due to the biallelic TLR7 expression, allowing them to mount a stronger and more protective IFN response early after infection. Studies exploring COVID-19 treatment via the TLR7-mediated IFN pathway should consider this sex difference. Various factors such as age, sex hormones and escape modulation remain to be investigated concerning the TLR7 gene-dose effect.


Subject(s)
COVID-19/mortality , Gene Dosage/genetics , Interferon Type I/biosynthesis , Toll-Like Receptor 7/genetics , Toll-Like Receptor 7/metabolism , COVID-19/drug therapy , COVID-19/pathology , Chromosomes, Human, X/genetics , Critical Care/statistics & numerical data , Dendritic Cells/immunology , Female , Humans , Interferon Type I/immunology , Male , RNA, Viral/genetics , Receptors, Pattern Recognition/genetics , Receptors, Pattern Recognition/metabolism , Risk Factors , SARS-CoV-2/immunology , Sex Factors , Signal Transduction/immunology , X Chromosome Inactivation/genetics
7.
J Clin Immunol ; 42(1): 1-9, 2022 01.
Article in English | MEDLINE | ID: covidwho-1482248

ABSTRACT

BACKGROUND: Coronavirus disease 2019 (COVID-19) exhibits a wide spectrum of clinical manifestations, ranging from asymptomatic to critical conditions. Understanding the mechanism underlying life-threatening COVID-19 is instrumental for disease prevention and treatment in individuals with a high risk. OBJECTIVES: We aimed to identify the genetic cause for critical COVID-19 pneumonia in a patient with a preexisting inborn error of immunity (IEI). METHODS: Serum levels of specific antibodies against the virus and autoantibodies against type I interferons (IFNs) were measured. Whole exome sequencing was performed, and the impacts of candidate gene variants were investigated. We also evaluated 247 ataxia-telangiectasia (A-T) patients in the Iranian IEI registry. RESULTS: We report a 7-year-old Iranian boy with a preexisting hyper IgM syndrome who developed critical COVID-19 pneumonia. IgM only specific COVID-19 immune response was detected but no autoantibodies against type I IFN were observed. A homozygous deleterious mutation in the ATM gene was identified, which together with his antibody deficiency, radiosensitivity, and neurological signs, established a diagnosis of A-T. Among the 247 A-T patients evaluated, 36 had SARS-CoV-2 infection, but all had mild symptoms or were asymptomatic except the index patient. A hemizygous deleterious mutation in the TLR7 gene was subsequently identified in the patient. CONCLUSIONS: We report a unique IEI patient with combined ATM and TLR7 deficiencies. The two genetic defects underlie A-T and critical COVID-19 in this patient, respectively.


Subject(s)
Ataxia Telangiectasia/genetics , COVID-19/genetics , Pneumonia/genetics , Toll-Like Receptor 7/deficiency , Toll-Like Receptor 7/genetics , Child , Humans , Iran , Male
8.
Sci Immunol ; 6(62)2021 08 19.
Article in English | MEDLINE | ID: covidwho-1434876

ABSTRACT

Autosomal inborn errors of type I IFN immunity and autoantibodies against these cytokines underlie at least 10% of critical COVID-19 pneumonia cases. We report very rare, biochemically deleterious X-linked TLR7 variants in 16 unrelated male individuals aged 7 to 71 years (mean: 36.7 years) from a cohort of 1,202 male patients aged 0.5 to 99 years (mean: 52.9 years) with unexplained critical COVID-19 pneumonia. None of the 331 asymptomatically or mildly infected male individuals aged 1.3 to 102 years (mean: 38.7 years) tested carry such TLR7 variants (p = 3.5 × 10-5). The phenotypes of five hemizygous relatives of index cases infected with SARS-CoV-2 include asymptomatic or mild infection (n=2, 5 and 38 years), or moderate (n=1, 5 years), severe (n=1, 27 years), or critical (n=1, 29 years) pneumonia. Two boys (aged 7 and 12 years) from a cohort of 262 male patients with severe COVID-19 pneumonia (mean: 51.0 years) are hemizygous for a deleterious TLR7 variant. The cumulative allele frequency for deleterious TLR7 variants in the male general population is < 6.5x10-4 We also show that blood B cell lines and myeloid cell subsets from the patients do not respond to TLR7 stimulation, a phenotype rescued by wild-type TLR7 The patients' blood plasmacytoid dendritic cells (pDCs) produce low levels of type I IFNs in response to SARS-CoV-2. Overall, X-linked recessive TLR7 deficiency is a highly penetrant genetic etiology of critical COVID-19 pneumonia, in about 1.8% of male patients below the age of 60 years. Human TLR7 and pDCs are essential for protective type I IFN immunity against SARS-CoV-2 in the respiratory tract.


Subject(s)
COVID-19/complications , Genetic Diseases, X-Linked/complications , Immune System Diseases/complications , Toll-Like Receptor 7/deficiency , Adolescent , Adult , Aged , Aged, 80 and over , Alleles , Child , Child, Preschool , Humans , Infant , Male , Middle Aged , Pedigree , Penetrance , Toll-Like Receptor 7/genetics , Young Adult
9.
Virol J ; 18(1): 180, 2021 09 05.
Article in English | MEDLINE | ID: covidwho-1388778

ABSTRACT

BACKGROUND: Covid-19 has the respiratory tract as the main target of infection, and patients present mainly dyspnea, pneumonia, dry cough, and fever. Nevertheless, organs outside the respiratory tract had been reported in recent studies, including the gastrointestinal tract and liver. The host innate immune system recognizes pathogen-associated molecular patterns (PAMPs) through their pattern recognition receptor (PRRs). Toll-like receptor 7 (TLR-7) is a pattern recognition receptor recognizing ssRNA (SARS-CoV-2 is an ssRNA). Polymorphisms are characterized by two or more alternative forms of a distinct phenotype in the same population. Polymorphisms in tlrs genes can negatively influence the immune response to infectious diseases. There are several references in the literature to non-synonymous single nucleotide (rs) polymorphisms related to several genes. Some of them are important for the innate immunity, as rs 179008 (tlr-7), rs3775291 (tlr3), rs8177374 (tir domain-containing adaptor protein, tirap), rs1024611 (monocyte chemoattractant protein-1, mcp-1) and rs61942233 (2'-5'-oligoadenylate synthase-3, oas-3). CASE PRESENTATION: We identified a 5-year-old-male child with gastrointestinal symptoms and fever presenting acholic stool and jaundice, who was positive for SARS-CoV-2 IgM, IgA, and IgG and presenting the Gln11Leu rs 179008 in tlr-7. The child presented high levels of aspartate aminotransferase, alanine aminotransferase, bilirubin, C-reactive protein, D-dimer, gamma-glutamyl transferase, alkaline phosphatase, and was negative for serological tests for hepatitis A, B, C, E, HIV 1 and 2, herpes virus, cytomegalovirus, Epstein-Barr virus, and negative for RTqPCR for Influenza A and B, RSV and SARS-CoV-2. We also investigated other SNPs in the tlr-3 (rs3775291), tirap (rs8177374), mcp-1 (rs1024611), and oas-3 (rs61942233) genes, and no mutation was detected. After an interview with the child's caregivers, any possible accidental ingestion of drugs or hepatotoxic substances was ruled out. CONCLUSION: To our knowledge, this is the first report of a SARS-CoV-2 caused hepatitis in a male child that has the tlr-7 Gln11Leu rs 179008, which could impair an efficient initial immune response. The knowledge of the patient's immune deficiency could improve the treatment to correct this deficiency with specific medications.


Subject(s)
COVID-19/genetics , COVID-19/virology , Hepatitis, Viral, Human/genetics , Hepatitis, Viral, Human/virology , Toll-Like Receptor 7/genetics , Antibodies, Viral/blood , COVID-19/immunology , Child, Preschool , Epstein-Barr Virus Infections/genetics , Epstein-Barr Virus Infections/virology , Feces/virology , Hepatitis, Viral, Human/immunology , Herpesvirus 4, Human/isolation & purification , Humans , Immunity, Innate , Influenza, Human , Male , Polymorphism, Single Nucleotide , SARS-CoV-2/isolation & purification
10.
Sci Immunol ; 6(62)2021 08 19.
Article in English | MEDLINE | ID: covidwho-1367380

ABSTRACT

Autosomal inborn errors of type I IFN immunity and autoantibodies against these cytokines underlie at least 10% of critical COVID-19 pneumonia cases. We report very rare, biochemically deleterious X-linked TLR7 variants in 16 unrelated male individuals aged 7 to 71 years (mean: 36.7 years) from a cohort of 1,202 male patients aged 0.5 to 99 years (mean: 52.9 years) with unexplained critical COVID-19 pneumonia. None of the 331 asymptomatically or mildly infected male individuals aged 1.3 to 102 years (mean: 38.7 years) tested carry such TLR7 variants (p = 3.5 × 10-5). The phenotypes of five hemizygous relatives of index cases infected with SARS-CoV-2 include asymptomatic or mild infection (n=2, 5 and 38 years), or moderate (n=1, 5 years), severe (n=1, 27 years), or critical (n=1, 29 years) pneumonia. Two boys (aged 7 and 12 years) from a cohort of 262 male patients with severe COVID-19 pneumonia (mean: 51.0 years) are hemizygous for a deleterious TLR7 variant. The cumulative allele frequency for deleterious TLR7 variants in the male general population is < 6.5x10-4 We also show that blood B cell lines and myeloid cell subsets from the patients do not respond to TLR7 stimulation, a phenotype rescued by wild-type TLR7 The patients' blood plasmacytoid dendritic cells (pDCs) produce low levels of type I IFNs in response to SARS-CoV-2. Overall, X-linked recessive TLR7 deficiency is a highly penetrant genetic etiology of critical COVID-19 pneumonia, in about 1.8% of male patients below the age of 60 years. Human TLR7 and pDCs are essential for protective type I IFN immunity against SARS-CoV-2 in the respiratory tract.


Subject(s)
COVID-19/complications , Genetic Diseases, X-Linked/complications , Immune System Diseases/complications , Toll-Like Receptor 7/deficiency , Adolescent , Adult , Aged , Aged, 80 and over , Alleles , Child , Child, Preschool , Humans , Infant , Male , Middle Aged , Pedigree , Penetrance , Toll-Like Receptor 7/genetics , Young Adult
11.
Front Immunol ; 12: 719115, 2021.
Article in English | MEDLINE | ID: covidwho-1348490

ABSTRACT

Introduction: Loss-of-function TLR7 variants have been recently reported in a small number of males to underlie strong predisposition to severe COVID-19. We aimed to determine the presence of these rare variants in young men with severe COVID-19. Methods: We prospectively studied males between 18 and 50 years-old without predisposing comorbidities that required at least high-flow nasal oxygen to treat COVID-19. The coding region of TLR7 was sequenced to assess the presence of potentially deleterious variants. Results: TLR7 missense variants were identified in two out of 14 patients (14.3%). Overall, the median age was 38 (IQR 30-45) years. Both variants were not previously reported in population control databases and were predicted to be damaging by in silico predictors. In a 30-year-old patient a maternally inherited variant [c.644A>G; p.(Asn215Ser)] was identified, co-segregating in his 27-year-old brother who also contracted severe COVID-19. A second variant [c.2797T>C; p.(Trp933Arg)] was found in a 28-year-old patient, co-segregating in his 24-year-old brother who developed mild COVID-19. Functional testing of this variant revealed decreased type I and II interferon responses in peripheral mononuclear blood cells upon stimulation with the TLR7 agonist imiquimod, confirming a loss-of-function effect. Conclusions: This study supports a rationale for the genetic screening for TLR7 variants in young men with severe COVID-19 in the absence of other relevant risk factors. A diagnosis of TLR7 deficiency could not only inform on treatment options for the patient, but also enables pre-symptomatic testing of at-risk male relatives with the possibility of instituting early preventive and therapeutic interventions.


Subject(s)
COVID-19/genetics , Mutation, Missense , SARS-CoV-2 , Toll-Like Receptor 7/genetics , Adult , Amino Acid Substitution , COVID-19/immunology , COVID-19/pathology , Genetic Testing , Humans , Male , Middle Aged , Risk Factors , Severity of Illness Index , Toll-Like Receptor 7/immunology
12.
J Innate Immun ; 13(6): 345-358, 2021.
Article in English | MEDLINE | ID: covidwho-1245277

ABSTRACT

Regulation of proinflammatory cytokine expression is critical in the face of single-stranded RNA (ssRNA) virus infections. Many viruses, including coronavirus and influenza virus, wreak havoc on the control of cytokine expression, leading to the formation of detrimental cytokine storms. Understanding the regulation and interplay between inflammatory cytokines is critical to the identification of targets involved in controlling the induction of cytokine expression. In this study, we focused on how the antiviral cytokine interleukin-27 (IL-27) regulates signal transduction downstream of Toll-like receptor 7 (TLR7) and TLR8 ligation, which recognize endosomal single-stranded RNA. Given that IL-27 alters bacterial-sensing TLR expression on myeloid cells and can inhibit replication of single-stranded RNA viruses, we investigated whether IL-27 affects expression and function of TLR7 and TLR8. Analysis of IL-27-treated THP-1 monocytic cells and THP-1-derived macrophages revealed changes in mRNA and protein expression of TLR7 and TLR8. Although treatment with IL-27 enhanced TLR7 expression, only TLR8-mediated cytokine secretion was amplified. Furthermore, we demonstrated that imiquimod, a TLR7 agonist, inhibited cytokine and chemokine production induced by a TLR8 agonist, TL8-506. Delineating the immunomodulatory role of IL-27 on TLR7 and TLR8 responses provides insight into how myeloid cell TLR-mediated responses are regulated during virus infection.


Subject(s)
Interleukin-27/immunology , Macrophages/immunology , Monocytes/immunology , Toll-Like Receptor 7/immunology , Toll-Like Receptor 8/immunology , Cytokines/immunology , Humans , Immunomodulation , Inflammation , RNA, Messenger/metabolism , Signal Transduction , THP-1 Cells , Toll-Like Receptor 7/genetics , Toll-Like Receptor 7/metabolism , Toll-Like Receptor 8/genetics , Toll-Like Receptor 8/metabolism
13.
Int Immunopharmacol ; 96: 107671, 2021 Jul.
Article in English | MEDLINE | ID: covidwho-1227634

ABSTRACT

Chlorogenic acid (CGA) is a phenolic compound that has been well studied for its antiviral, anti-inflammatory and immune stimulating properties. This research was aimed to focus on the antiviral properties of CGA on infectious bronchitis virus (IBV) in vivo and in vitro for the very first time. The outcome of in vitro experiments validated that, out of five previously reported antiviral components, CGA significantly reduced the relative mRNA expression of IBV-N in CEK cells. At high concentration (400 mg/kg), CGA supplementation reduced IBV-N mRNA expression levels and ameliorated the injury in trachea and lungs. The mRNA expression levels of IL-6, IL-1ß, IL-12, and NF-κB were considerably turned down, but IL-22 and IL-10 were enhanced in trachea. However, CGA-H treatment had considerably increased the expression levels of MDA5, MAVS, TLR7, MyD88, IRF7, IFN-ß and IFN-α both in trachea and lungs. Moreover, CGA-H notably induced the CD3+, CD3+ CD4+ and CD4+/CD8+ proliferation and significantly increased the IgA, IgG, and IgM levels in the serum. In conclusion, these results showed that at high concentration CGA is a strong anti-IBV compound that can effectively regulate the innate immunity through MDA5, TLR7 and NF-κB signaling pathways and have the potential to induce the cell mediated and humoral immune response in IBV infected chickens.


Subject(s)
Chlorogenic Acid/pharmacology , Coronavirus Infections/drug therapy , Gammacoronavirus/drug effects , Interferon-Induced Helicase, IFIH1/metabolism , NF-kappa B/metabolism , Toll-Like Receptor 7/metabolism , Animals , Anti-Inflammatory Agents/pharmacology , Antiviral Agents/pharmacology , Cells, Cultured , Chickens , Coronavirus Infections/immunology , Coronavirus Infections/virology , Disease Models, Animal , Gammacoronavirus/immunology , Gammacoronavirus/isolation & purification , Immunity, Innate , Interferon-Induced Helicase, IFIH1/genetics , NF-kappa B/genetics , Toll-Like Receptor 7/genetics
14.
Elife ; 102021 03 02.
Article in English | MEDLINE | ID: covidwho-1112866

ABSTRACT

Background: Recently, loss-of-function variants in TLR7 were identified in two families in which COVID-19 segregates like an X-linked recessive disorder environmentally conditioned by SARS-CoV-2. We investigated whether the two families represent the tip of the iceberg of a subset of COVID-19 male patients. Methods: This is a nested case-control study in which we compared male participants with extreme phenotype selected from the Italian GEN-COVID cohort of SARS-CoV-2-infected participants (<60 y, 79 severe cases versus 77 control cases). We applied the LASSO Logistic Regression analysis, considering only rare variants on young male subsets with extreme phenotype, picking up TLR7 as the most important susceptibility gene. Results: Overall, we found TLR7 deleterious variants in 2.1% of severely affected males and in none of the asymptomatic participants. The functional gene expression profile analysis demonstrated a reduction in TLR7-related gene expression in patients compared with controls demonstrating an impairment in type I and II IFN responses. Conclusions: Young males with TLR7 loss-of-function variants and severe COVID-19 represent a subset of male patients contributing to disease susceptibility in up to 2% of severe COVID-19. Funding: Funded by private donors for the Host Genetics Research Project, the Intesa San Paolo for 2020 charity fund, and the Host Genetics Initiative. Clinical trial number: NCT04549831.


Subject(s)
COVID-19/genetics , Polymorphism, Single Nucleotide , Toll-Like Receptor 7/genetics , Adult , COVID-19/diagnosis , COVID-19/epidemiology , Case-Control Studies , Genetic Predisposition to Disease , HEK293 Cells , Humans , Italy/epidemiology , Male , Middle Aged , SARS-CoV-2/isolation & purification , Severity of Illness Index
15.
J Proteome Res ; 20(1): 139-153, 2021 01 01.
Article in English | MEDLINE | ID: covidwho-965927

ABSTRACT

Spurred into action by the COVID-19 pandemic, the global scientific community has, in a short of period of time, made astonishing progress in understanding and combating COVID-19. Given the known human protein machinery for (a) SARS-CoV-2 entry, (b) the host innate immune response, and (c) virus-host interactions (protein-protein and RNA-protein), the potential effects of human genetic variation in this machinery, which may contribute to clinical differences in SARS-CoV-2 pathogenesis and help determine individual risk for COVID-19 infection, are explored. The Genome Aggregation Database (gnomAD) was used to show that several rare germline exome variants of proteins in these pathways occur in the human population, suggesting that carriers of these rare variants (especially for proteins of innate immunity pathways) are at risk for severe symptoms (like the severe symptoms in patients who are known to be rare variant carriers), whereas carriers of other variants could have a protective advantage against infection. The occurrence of genetic variation is thus expected to motivate the experimental probing of natural variants to understand the mechanistic differences in SARS-CoV-2 pathogenesis from one individual to another.


Subject(s)
COVID-19/genetics , Genetic Variation , Host-Pathogen Interactions/genetics , SARS-CoV-2/pathogenicity , Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , COVID-19/immunology , Humans , Immunity, Innate/genetics , Quantitative Trait Loci , RNA, Viral/metabolism , Toll-Like Receptor 3/genetics , Toll-Like Receptor 7/genetics , Virus Internalization
16.
Int J Mol Sci ; 21(23)2020 Nov 25.
Article in English | MEDLINE | ID: covidwho-951247

ABSTRACT

Activation of TLR7 by small imidazoquinoline molecules such as R848 or R837 initiates signaling cascades leading to the activation of transcription factors, such as AP-1, NF-κB, and interferon regulatory factors (IRFs) and afterward to the induction of cytokines and anti-viral Type I IFNs. In general, TLRs mediate these effects by utilizing different intracellular signaling molecules, one of them is Mal. Mal is a protein closely related to the antibacterial response, and its role in the TLR7 pathways remains poorly understood. In this study, we show that Mal determines the expression and secretion of IFNß following activation of TLR7, a receptor that recognizes ssRNA and imidazoquinolines. Moreover, we observed that R848 induces Mal-dependent IFNß production via ERK1/2 activation as well as the transcription factor IRF7 activation. Although activation of TLR7 leads to NF-κB-dependent expression of IRF7, this process is independent of Mal. We also demonstrate that secretion of IFNß regulated by TLR7 and Mal in macrophages and dendritic cells leads to the IP-10 chemokine expression. In conclusion, our data demonstrate that Mal is a critical regulator of the imidazoquinolinones-dependent IFNß production via ERK1/2/IRF7 signaling cascade which brings us closer to understanding the molecular mechanism's regulation of innate immune response.


Subject(s)
Interferon Regulatory Factor-7/genetics , Interferon-beta/genetics , Membrane Glycoproteins/genetics , Myelin and Lymphocyte-Associated Proteolipid Proteins/genetics , Toll-Like Receptor 7/genetics , Animals , Cytokines/genetics , Humans , Immunity, Innate/genetics , Interferon Type I/genetics , MAP Kinase Signaling System/genetics , Mice , Mice, Knockout , NF-kappa B/genetics , Quinolones/toxicity , Transcription Factor AP-1/genetics
17.
Infect Genet Evol ; 85: 104507, 2020 11.
Article in English | MEDLINE | ID: covidwho-731865

ABSTRACT

The COVID-19 pandemic highlighted healthcare disparities in multiple countries. As such morbidity and mortality vary significantly around the globe between populations and ethnic groups. Underlying medical conditions and environmental factors contribute higher incidence in some populations and a genetic predisposition may play a role for severe cases with respiratory failure. Here we investigated whether genetic variation in the key genes for viral entry to host cells-ACE2 and TMPRSS2-and sensing of viral genomic RNAs (i.e., TLR3/7/8) could explain the variation in incidence across diverse ethnic groups. Overall, these genes are under strong selection pressure and have very few nonsynonymous variants in all populations. Genetic determinant for the binding affinity between SARS-CoV-2 and ACE2 does not show significant difference between populations. Non-genetic factors are likely to contribute differential population characteristics affected by COVID-19. Nonetheless, a systematic mutagenesis study on the receptor binding domain of ACE2 is required to understand the difference in host-viral interaction across populations.


Subject(s)
Angiotensin-Converting Enzyme 2/genetics , SARS-CoV-2/physiology , Serine Endopeptidases/genetics , Toll-Like Receptors/genetics , Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/metabolism , Binding Sites , Humans , Mutagenesis, Site-Directed , Protein Binding , Protein Domains , Selection, Genetic , Serine Endopeptidases/metabolism , Toll-Like Receptor 3/chemistry , Toll-Like Receptor 3/genetics , Toll-Like Receptor 3/metabolism , Toll-Like Receptor 7/chemistry , Toll-Like Receptor 7/genetics , Toll-Like Receptor 7/metabolism , Toll-Like Receptor 8/chemistry , Toll-Like Receptor 8/genetics , Toll-Like Receptor 8/metabolism , Toll-Like Receptors/chemistry , Toll-Like Receptors/metabolism , Virus Internalization
18.
Diagnosis (Berl) ; 7(4): 385-386, 2020 Nov 18.
Article in English | MEDLINE | ID: covidwho-605555

ABSTRACT

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome (SARS) coronavirus 2 (SARS-CoV-2), shares similarities with the former SARS outbreak, which was caused by SARS-CoV-1. SARS was characterized by severe lung injury due to virus-induced cytopathic effects and dysregulated hyperinflammatory state. COVID-19 has a higher mortality rate in men both inside and outside China. In this opinion paper, we describe how sex-specific immunobiological factors and differences in angiotensin converting enzyme 2 (ACE2) expression may explain the increased severity and mortality of COVID-19 in males. We highlight that immunomodulatory treatment must be tailored to the underlying immunobiology at different stages of disease. Moreover, by investigating sex-based immunobiological differences, we may enhance our understanding of COVID-19 pathophysiology and facilitate improved immunomodulatory strategies.


Subject(s)
Coronavirus Infections/immunology , Coronavirus Infections/mortality , Peptidyl-Dipeptidase A/metabolism , Pneumonia, Viral/immunology , Pneumonia, Viral/mortality , Angiotensin-Converting Enzyme 2 , Animals , Antiviral Agents/pharmacology , Betacoronavirus/drug effects , CD4 Lymphocyte Count/statistics & numerical data , COVID-19 , Coronavirus Infections/therapy , Coronavirus Infections/virology , Cytokines/metabolism , Female , Humans , Immunomodulation , Interferon-alpha/drug effects , Interferon-alpha/immunology , Lymphopenia/mortality , Male , Membrane Glycoproteins/genetics , Mice , Models, Animal , Pandemics , Pneumonia, Viral/therapy , Pneumonia, Viral/virology , SARS-CoV-2 , Sex Factors , Toll-Like Receptor 7/genetics
19.
J Biol Regul Homeost Agents ; 34(3): 1125-1129, 2020.
Article in English | MEDLINE | ID: covidwho-381957

ABSTRACT

I hypothesize that chronic stimulation of tlr7 by intrinsic substrates in old and obese people leads to a desensitization of tlr7-signalling such that upon viral infection the immune response in those patients will be delayed, allowing the virus to more easily establish itself in these at-risk patient groups. Upon severe viral infection, resensitization of tlr7-signalling occurs so as to better fight the viral infection. This, however, leads to a situation where old and obese patients develop an overwhelming tlr7-response due to the presence of not only the viral RNA, but also the intrinsic tlr7 substrates. Thus, old and obese patients with serious COVID-19 develop a state that is similar to SLE-patients and consequently should be treated in a similar manner. The theory predicts that drugs and treatment regimens that help to control SLE-flares might also help in late-stage COVID-19 patients.


Subject(s)
COVID-19 , Disease Susceptibility , Obesity/genetics , Toll-Like Receptor 7 , Aged , Humans , Male , Toll-Like Receptor 7/genetics
20.
BMC Med Genet ; 21(1): 113, 2020 05 25.
Article in English | MEDLINE | ID: covidwho-361259

ABSTRACT

BACKGROUND: Maternal cytomegalovirus (CMV) infection and/or reactivation in pregnancy is associated with a myriad of adverse infant outcomes. However, the role of host genetic polymorphisms in modulating maternal CMV status is inconclusive. This study investigated the possible association of single nucleotide polymorphisms in toll-like receptor (TLR) and cytokine genes with maternal plasma CMV DNA status in black Zimbabweans. METHODS: In a cross-sectional study, 110 women in late gestation who included 36 CMV infected cases and 74 CMV uninfected, age and HIV status matched controls were enrolled. Twenty single nucleotide polymorphisms in 10 genes which code for proteins involved in immunity against CMV were genotyped using Iplex GOLD SNP genotyping protocol on the Agena MassARRAY® system. Statistical analyses were performed using Stata SE and the 'Genetics' and 'SNPassoc' packages of the statistical package R. RESULTS: The TLR7 rs179008A > T (p < 0.001) polymorphism was associated while the TLR9 rs352139T > C (p = 0.049) polymorphism was on the borderline for association with CMV positive (CMV+) status. In contrast, the interleukin (IL)-6 rs10499563T > C (p < 0.001) and TLR2 rs1816702C > T (p = 0.001) polymorphisms were associated with CMV negative (CMV-) status. Furthermore, allele frequencies of SNPs in TLR2, TLR4, TLR9, TLR7, IL-6, IL-10, IL-28B, IL-1A and interferon AR1 (IFNAR1) genes are being reported here for the first time in a Zimbabwean population. The allele frequencies in the Zimbabwean population are generally comparable to other African populations but different when compared to European and Asian populations. CONCLUSIONS: Toll-like receptor and interleukin genetic polymorphisms influence CMV status in late gestation among black Zimbabweans. This is attributable to possible modulation of immune responses to CMV reactivation in a population previously exposed to CMV infection.


Subject(s)
Cytomegalovirus Infections/diagnosis , Cytomegalovirus Infections/etiology , Cytomegalovirus , Genetic Variation , Interleukin-6/genetics , Pregnancy Complications, Infectious , Toll-Like Receptors/genetics , Adolescent , Adult , Alleles , Cytomegalovirus/immunology , Disease Susceptibility , Female , Gene Frequency , Genetic Predisposition to Disease , Genotype , Humans , Male , Odds Ratio , Polymorphism, Single Nucleotide , Pregnancy , Toll-Like Receptor 2/genetics , Toll-Like Receptor 7/genetics , Toll-Like Receptor 9/genetics , Young Adult
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