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1.
Proc Natl Acad Sci U S A ; 119(18): e2123560119, 2022 05 03.
Article in English | MEDLINE | ID: covidwho-1805767

ABSTRACT

The duper mutation is a recessive mutation that shortens the period length of the circadian rhythm in Syrian hamsters. These animals show a large phase shift when responding to light pulses. Limited genetic resources for the Syrian hamster (Mesocricetus auratus) presented a major obstacle to cloning duper. This caused the duper mutation to remain unknown for over a decade. In this study, we did a de novo genome assembly of Syrian hamsters with long-read sequencing data from two different platforms, Pacific Biosciences and Oxford Nanopore Technologies. Using two distinct ecotypes and a fast homozygosity mapping strategy, we identified duper as an early nonsense allele of Cryptochrome 1 (Cry1) leading to a short, unstable protein. CRY1 is known as a highly conserved component of the repressive limb of the core circadian clock. The genome assembly and other genomic datasets generated in this study will facilitate the use of the Syrian hamster in biomedical research.


Subject(s)
COVID-19 , Cryptochromes , Animals , Circadian Rhythm/genetics , Cricetinae , Cryptochromes/genetics , Humans , Loss of Function Mutation , Mesocricetus , Mutation , Transcription Factors/genetics
2.
Int J Mol Sci ; 23(5)2022 Feb 22.
Article in English | MEDLINE | ID: covidwho-1736940

ABSTRACT

Contrary to public perception, hypertension remains one of the most important public health problems in the United States, affecting 46% of adults with increased risk for heart attack, stroke, and kidney diseases. The mechanisms underlying poorly controlled hypertension remain incompletely understood. Recent development in the Cre/LoxP approach to study gain or loss of function of a particular gene has significantly helped advance our new insights into the role of proximal tubule angiotensin II (Ang II) and its AT1 (AT1a) receptors in basal blood pressure control and the development of Ang II-induced hypertension. This novel approach has provided us and others with an important tool to generate novel mouse models with proximal tubule-specific loss (deletion) or gain of the function (overexpression). The objective of this invited review article is to review and discuss recent findings using novel genetically modifying proximal tubule-specific mouse models. These new studies have consistently demonstrated that deletion of AT1 (AT1a) receptors or its direct downstream target Na+/H+ exchanger 3 (NHE3) selectively in the proximal tubules of the kidney lowers basal blood pressure, increases the pressure-natriuresis response, and induces natriuretic responses, whereas overexpression of an intracellular Ang II fusion protein or AT1 (AT1a) receptors selectively in the proximal tubules increases proximal tubule Na+ reabsorption, impairs the pressure-natriuresis response, and elevates blood pressure. Furthermore, the development of Ang II-induced hypertension by systemic Ang II infusion or by proximal tubule-specific overexpression of an intracellular Ang II fusion protein was attenuated in mutant mice with proximal tubule-specific deletion of AT1 (AT1a) receptors or NHE3. Thus, these recent studies provide evidence for and new insights into the important roles of intratubular Ang II via AT1 (AT1a) receptors and NHE3 in the proximal tubules in maintaining basal blood pressure homeostasis and the development of Ang II-induced hypertension.


Subject(s)
Angiotensin II/metabolism , Hypertension/metabolism , Receptor, Angiotensin, Type 1/metabolism , Angiotensin II/genetics , Animals , Blood Pressure , Disease Models, Animal , Gain of Function Mutation , Humans , Hypertension/genetics , Loss of Function Mutation , Mice , Receptor, Angiotensin, Type 1/genetics , Sodium-Hydrogen Exchanger 3/metabolism
3.
J Clin Immunol ; 41(7): 1446-1456, 2021 10.
Article in English | MEDLINE | ID: covidwho-1453806

ABSTRACT

STAT2 is distinguished from other STAT family members by its exclusive involvement in type I and III interferon (IFN-I/III) signaling pathways, and its unique behavior as both positive and negative regulator of IFN-I signaling. The clinical relevance of these opposing STAT2 functions is exemplified by monogenic diseases of STAT2. Autosomal recessive STAT2 deficiency results in heightened susceptibility to severe and/or recurrent viral disease, whereas homozygous missense substitution of the STAT2-R148 residue is associated with severe type I interferonopathy due to loss of STAT2 negative regulation. Here we review the clinical presentation, pathogenesis, and management of these disorders of STAT2.


Subject(s)
Genetic Diseases, Inborn/genetics , Immune System Diseases/genetics , Interferon Type I/immunology , STAT2 Transcription Factor/genetics , Virus Diseases/genetics , Animals , Gain of Function Mutation , Genetic Diseases, Inborn/immunology , Genetic Predisposition to Disease , Humans , Immune System Diseases/immunology , Loss of Function Mutation , Phenotype , STAT2 Transcription Factor/chemistry , STAT2 Transcription Factor/immunology , Virus Diseases/immunology
4.
J Clin Invest ; 131(14)2021 07 15.
Article in English | MEDLINE | ID: covidwho-1365266

ABSTRACT

A recent report found that rare predicted loss-of-function (pLOF) variants across 13 candidate genes in TLR3- and IRF7-dependent type I IFN pathways explain up to 3.5% of severe COVID-19 cases. We performed whole-exome or whole-genome sequencing of 1,864 COVID-19 cases (713 with severe and 1,151 with mild disease) and 15,033 ancestry-matched population controls across 4 independent COVID-19 biobanks. We tested whether rare pLOF variants in these 13 genes were associated with severe COVID-19. We identified only 1 rare pLOF mutation across these genes among 713 cases with severe COVID-19 and observed no enrichment of pLOFs in severe cases compared to population controls or mild COVID-19 cases. We found no evidence of association of rare LOF variants in the 13 candidate genes with severe COVID-19 outcomes.


Subject(s)
COVID-19/genetics , COVID-19/immunology , Interferon Type I/genetics , Interferon Type I/immunology , Loss of Function Mutation , SARS-CoV-2 , Adolescent , Adult , Aged , Aged, 80 and over , Case-Control Studies , Child , Child, Preschool , Cohort Studies , Female , Genetic Association Studies , Genetic Predisposition to Disease , Humans , Infant , Infant, Newborn , Interferon Regulatory Factor-7/genetics , Male , Middle Aged , Severity of Illness Index , Toll-Like Receptor 3/genetics , Whole Exome Sequencing , Whole Genome Sequencing , Young Adult
5.
J Clin Invest ; 131(14)2021 07 15.
Article in English | MEDLINE | ID: covidwho-1247462

ABSTRACT

A recent report found that rare predicted loss-of-function (pLOF) variants across 13 candidate genes in TLR3- and IRF7-dependent type I IFN pathways explain up to 3.5% of severe COVID-19 cases. We performed whole-exome or whole-genome sequencing of 1,864 COVID-19 cases (713 with severe and 1,151 with mild disease) and 15,033 ancestry-matched population controls across 4 independent COVID-19 biobanks. We tested whether rare pLOF variants in these 13 genes were associated with severe COVID-19. We identified only 1 rare pLOF mutation across these genes among 713 cases with severe COVID-19 and observed no enrichment of pLOFs in severe cases compared to population controls or mild COVID-19 cases. We found no evidence of association of rare LOF variants in the 13 candidate genes with severe COVID-19 outcomes.


Subject(s)
COVID-19/genetics , COVID-19/immunology , Interferon Type I/genetics , Interferon Type I/immunology , Loss of Function Mutation , SARS-CoV-2 , Adolescent , Adult , Aged , Aged, 80 and over , Case-Control Studies , Child , Child, Preschool , Cohort Studies , Female , Genetic Association Studies , Genetic Predisposition to Disease , Humans , Infant , Infant, Newborn , Interferon Regulatory Factor-7/genetics , Male , Middle Aged , Severity of Illness Index , Toll-Like Receptor 3/genetics , Whole Exome Sequencing , Whole Genome Sequencing , Young Adult
6.
Trends Microbiol ; 29(11): 973-982, 2021 11.
Article in English | MEDLINE | ID: covidwho-1142259

ABSTRACT

Pandemics are caused by novel pathogens to which pre-existing antibody immunity is lacking. Under these circumstances, the body must rely on innate interferon-mediated defenses to limit pathogen replication and allow development of critical humoral protection. Here, we highlight studies on disease susceptibility during H1N1 influenza and COVID-19 (SARS-CoV-2) pandemics. An emerging concept is that genetic and non-genetic deficiencies in interferon system components lead to uncontrolled virus replication and severe illness in a subset of people. Intriguingly, new findings suggest that individuals with autoantibodies neutralizing the antiviral function of interferon are at increased risk of severe COVID-19. We discuss key questions surrounding how such autoantibodies develop and function, as well as the general implications of diagnosing interferon deficiencies for personalized therapies.


Subject(s)
Disease Resistance , Host-Pathogen Interactions , Interferons/metabolism , Virus Diseases/etiology , Virus Diseases/metabolism , Alleles , Animals , Antibodies, Neutralizing/immunology , Autoantibodies/immunology , Autoimmunity , Disease Progression , Disease Resistance/immunology , Disease Susceptibility , Genetic Predisposition to Disease , Host-Pathogen Interactions/immunology , Humans , Interferons/antagonists & inhibitors , Interferons/immunology , Loss of Function Mutation , Polymorphism, Single Nucleotide , Severity of Illness Index , Virus Diseases/diagnosis , Virus Diseases/epidemiology
7.
Cell ; 184(4): 1064-1080.e20, 2021 02 18.
Article in English | MEDLINE | ID: covidwho-1086818

ABSTRACT

Understanding the functional consequences of single-nucleotide variants is critical to uncovering the genetic underpinnings of diseases, but technologies to characterize variants are limiting. Here, we leverage CRISPR-Cas9 cytosine base editors in pooled screens to scalably assay variants at endogenous loci in mammalian cells. We benchmark the performance of base editors in positive and negative selection screens, identifying known loss-of-function mutations in BRCA1 and BRCA2 with high precision. To demonstrate the utility of base editor screens to probe small molecule-protein interactions, we screen against BH3 mimetics and PARP inhibitors, identifying point mutations that confer drug sensitivity or resistance. We also create a library of single guide RNAs (sgRNAs) predicted to generate 52,034 ClinVar variants in 3,584 genes and conduct screens in the presence of cellular stressors, identifying loss-of-function variants in numerous DNA damage repair genes. We anticipate that this screening approach will be broadly useful to readily and scalably functionalize genetic variants.


Subject(s)
Gene Editing , Genetic Variation , High-Throughput Nucleotide Sequencing , Alleles , BRCA1 Protein/genetics , BRCA2 Protein/genetics , Base Sequence , Catalytic Domain , Cell Line, Tumor , Humans , Loss of Function Mutation , Mutagenesis/genetics , Myeloid Cell Leukemia Sequence 1 Protein/genetics , Point Mutation/genetics , Poly(ADP-ribose) Polymerases/chemistry , Poly(ADP-ribose) Polymerases/genetics , Reproducibility of Results , Selection, Genetic , bcl-X Protein/genetics
8.
Science ; 370(6515)2020 10 23.
Article in English | MEDLINE | ID: covidwho-796722

ABSTRACT

Clinical outcome upon infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ranges from silent infection to lethal coronavirus disease 2019 (COVID-19). We have found an enrichment in rare variants predicted to be loss-of-function (LOF) at the 13 human loci known to govern Toll-like receptor 3 (TLR3)- and interferon regulatory factor 7 (IRF7)-dependent type I interferon (IFN) immunity to influenza virus in 659 patients with life-threatening COVID-19 pneumonia relative to 534 subjects with asymptomatic or benign infection. By testing these and other rare variants at these 13 loci, we experimentally defined LOF variants underlying autosomal-recessive or autosomal-dominant deficiencies in 23 patients (3.5%) 17 to 77 years of age. We show that human fibroblasts with mutations affecting this circuit are vulnerable to SARS-CoV-2. Inborn errors of TLR3- and IRF7-dependent type I IFN immunity can underlie life-threatening COVID-19 pneumonia in patients with no prior severe infection.


Subject(s)
Coronavirus Infections/genetics , Coronavirus Infections/immunology , Interferon Type I/immunology , Loss of Function Mutation , Pneumonia, Viral/genetics , Pneumonia, Viral/immunology , Adolescent , Adult , Aged , Aged, 80 and over , Alleles , Asymptomatic Infections , Betacoronavirus , COVID-19 , Child , Child, Preschool , Female , Genetic Loci , Genetic Predisposition to Disease , Humans , Infant , Interferon Regulatory Factor-7/deficiency , Interferon Regulatory Factor-7/genetics , Male , Middle Aged , Pandemics , Receptor, Interferon alpha-beta/deficiency , Receptor, Interferon alpha-beta/genetics , SARS-CoV-2 , Toll-Like Receptor 3/deficiency , Toll-Like Receptor 3/genetics , Young Adult
9.
JAMA ; 324(7): 663-673, 2020 08 18.
Article in English | MEDLINE | ID: covidwho-676817

ABSTRACT

Importance: Severe coronavirus disease 2019 (COVID-19) can occur in younger, predominantly male, patients without preexisting medical conditions. Some individuals may have primary immunodeficiencies that predispose to severe infections caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Objective: To explore the presence of genetic variants associated with primary immunodeficiencies among young patients with COVID-19. Design, Setting, and Participants: Case series of pairs of brothers without medical history meeting the selection criteria of young (age <35 years) brother pairs admitted to the intensive care unit (ICU) due to severe COVID-19. Four men from 2 unrelated families were admitted to the ICUs of 4 hospitals in the Netherlands between March 23 and April 12, 2020. The final date of follow-up was May 16, 2020. Available family members were included for genetic variant segregation analysis and as controls for functional experiments. Exposure: Severe COVID-19. Main Outcome and Measures: Results of rapid clinical whole-exome sequencing, performed to identify a potential monogenic cause. Subsequently, basic genetic and immunological tests were performed in primary immune cells isolated from the patients and family members to characterize any immune defects. Results: The 4 male patients had a mean age of 26 years (range, 21-32), with no history of major chronic disease. They were previously well before developing respiratory insufficiency due to severe COVID-19, requiring mechanical ventilation in the ICU. The mean duration of ventilatory support was 10 days (range, 9-11); the mean duration of ICU stay was 13 days (range, 10-16). One patient died. Rapid clinical whole-exome sequencing of the patients and segregation in available family members identified loss-of-function variants of the X-chromosomal TLR7. In members of family 1, a maternally inherited 4-nucleotide deletion was identified (c.2129_2132del; p.[Gln710Argfs*18]); the affected members of family 2 carried a missense variant (c.2383G>T; p.[Val795Phe]). In primary peripheral blood mononuclear cells from the patients, downstream type I interferon (IFN) signaling was transcriptionally downregulated, as measured by significantly decreased mRNA expression of IRF7, IFNB1, and ISG15 on stimulation with the TLR7 agonist imiquimod as compared with family members and controls. The production of IFN-γ, a type II IFN, was decreased in patients in response to stimulation with imiquimod. Conclusions and Relevance: In this case series of 4 young male patients with severe COVID-19, rare putative loss-of-function variants of X-chromosomal TLR7 were identified that were associated with impaired type I and II IFN responses. These preliminary findings provide insights into the pathogenesis of COVID-19.


Subject(s)
COVID-19/virology , Loss of Function Mutation , SARS-CoV-2/genetics , Adult , Enzyme-Linked Immunosorbent Assay , Fatal Outcome , Hospitalization , Humans , Intensive Care Units , Leukocytes, Mononuclear , Male , Netherlands , Pedigree , RNA, Viral/analysis , Real-Time Polymerase Chain Reaction , SARS-CoV-2/isolation & purification , Young Adult
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