Cell-type-specific co-expression inference from single cell RNA-sequencing data (preprint)

The inference of gene co-expressions from microarray and RNA-sequencing data has led to rich insights on biological processes and disease mechanisms. However, the bulk samples analyzed in most studies are a mixture of different cell types. As a result, the inferred co-expressions are confounded by varying cell type compositions across samples and only offer an aggregated view of gene regulations that may be distinct across different cell types. The advancement of single cell RNA-sequencing (scRNA-seq) technology has enabled the direct inference of co-expressions in specific cell types, facilitating our understanding of cell-type-specific biological functions. However, the high sequencing depth variations and measurement errors in scRNA-seq data present significant challenges in inferring cell-type-specific gene co-expressions, and these issues have not been adequately addressed in the existing methods. We propose a statistical approach, CS-CORE, for estimating and testing cell-type-specific co-expressions, built on a general expression-measurement model that explicitly accounts for sequencing depth variations and measurement errors in the observed single cell data. Systematic evaluations show that most existing methods suffer from inflated false positives and biased co-expression estimates and clustering analysis, whereas CS-CORE has appropriate false positive control, unbiased co-expression estimates, good statistical power and satisfactory performance in downstream co-expression analysis. When applied to analyze scRNA-seq data from postmortem brain samples from Alzheimer's disease patients and controls and blood samples from COVID-19 patients and controls, CS-CORE identified cell-type-specific co-expressions and differential co-expressions that were more reproducible and/or more enriched for relevant biological pathways than those inferred from other methods.

Evaluating the Lower Urinary Tract Syndrome with a Telemedicine Application: An Exploration of the Electronic Audiovisual Prostate Symptom Score

Background The Visual Prostate Symptom Score (VPSS) is used for the assessment of lower urinary tract symptoms (LUTS). It is usually administered by general practitioners (GPs), but in these cases, outcomes do not seem to be reflecting the real conditions of a patient well, with consequent risks of misestimations and misinterpretations. We developed an electronic audiovisual version of VPSS (EPSS), a new symptom scale based on a telemedicine mobile light-based app. The aim of this study is to test and evaluate its reliability. Methods We enrolled male patients aged between 50 and 80 years across 24 community-based healthcare facilities in Guangzhou, China. Patients were asked to complete the Chinese version of VPSS and EPSS before consultation with the urology specialists. Patients were divided into two groups based on age. First, we analyzed the rate of full understanding of EPSS using a chi-square test. Then, we analyzed the difference between each score of EPSS, VPSS, and outcomes measured by specialists, used as the reference score (RS). Finally, the outcomes were analyzed with the Spearman test and Bartlett test separately. Results Seventy-nine male patients were included (mean age 70.42 years). Patients were divided into two groups: group 1 (>70 years, n = 40) and group 2 (<70 years, n = 39). The full-understanding rates in groups 1 and 2 were 50% and 64.1%, respectively. No significant differences were noted between groups (p = 0.206). A t-test was presented between each question of VPSS, EPSS, and RS. All questions did not display significant differences (p > 0.05);total scores from the three scales had no significant differences in the evaluation of LUTS. We further explored the variations of choices made by patients in different scales. Spearman’s test among VPSS, EPSS, and RS showed positive correlations, and coefficients of the total score were 0.92, 0.91, and 0.93 (p < 0.05). Conclusion EPSS can be easily used in a significant number of patients and showed correlation with the VPSS and RS. Moreover, certain items resulted in better performance than VPSS. The results showed that EPSS could be a valuable option for both patients and GPs monitoring LUTS and particularly helpful when teleconsultations are considered, especially during the COVID-19 pandemic.

Simultaneous and sequential multi-species coronavirus vaccination (preprint)

Although successful COVID-19 vaccines have been developed, multiple pathogenic coronavirus species exist, urging for development of multi-species coronavirus vaccines. Here we developed prototype LNP-mRNA vaccine candidates against SARS-CoV-2 (Delta variant), SARS-CoV and MERS-CoV, and test how multiplexing of these LNP-mRNAs can induce effective immune responses in animal models. A triplex scheme of LNP-mRNA vaccination induced antigen-specific antibody responses against SARS-CoV-2, SARS-CoV and MERS-CoV, with a relatively weaker MERS-CoV response in this setting. Single cell RNA-seq profiled the global systemic immune repertoires and the respective transcriptome signatures of multiplexed vaccinated animals, which revealed a systemic increase in activated B cells, as well as differential gene expression signatures across major adaptive immune cells. Sequential vaccination showed potent antibody responses against all three species, significantly stronger than simultaneous vaccination in mixture. These data demonstrated the feasibility, antibody responses and single cell immune profiles of multi-species coronavirus vaccination. The direct comparison between simultaneous and sequential vaccination offers insights on optimization of vaccination schedules to provide broad and potent antibody immunity against three major pathogenic coronavirus species.

A Phenome-Wide Association Study of genes associated with COVID-19 severity reveals shared genetics with complex diseases in the Million Veteran Program (preprint)

The study aims to determine the shared genetic architecture between COVID-19 severity with existing medical conditions using electronic health record (EHR) data. We conducted a Phenome-Wide Association Study (PheWAS) of genetic variants associated with critical illness (n=35) or hospitalization (n=42) due to severe COVID-19 using genome-wide association summary from the Host Genetics Initiative. PheWAS analysis was performed using genotype-phenotype data from the Veterans Affairs Million Veteran Program (MVP). Phenotypes were defined by International Classification of Diseases (ICD) codes mapped to clinically relevant groups using published PheWAS methods. Among 658,582 Veterans, variants associated with severe COVID-19 were tested for association across 1,559 phenotypes. Variants at the ABO locus (rs495828, rs505922) associated with the largest number of phenotypes (nrs495828= 53 and nrs505922=59); strongest association with venous embolism, odds ratio (ORrs495828 1.33 (p=1.32 x 10-199), and thrombosis ORrs505922 1.33, p=2.2 x10-265. Among 67 respiratory conditions tested, 11 had significant associations including MUC5B locus (rs35705950) with increased risk of idiopathic fibrosing alveolitis OR 2.83, p=4.12 x 10-191; CRHR1 (rs61667602) associated with reduced risk of pulmonary fibrosis, OR 0.84, p=2.26x 10-12. The TYK2 locus (rs11085727) associated with reduced risk for autoimmune conditions, e.g., psoriasis OR 0.88, p=6.48 x10-23, lupus OR 0.84, p=3.97 x 10-06. PheWAS stratified by genetic ancestry demonstrated differences in genotype-phenotype associations across ancestry. LMNA (rs581342) associated with neutropenia OR 1.29 p=4.1 x 10-13 among Veterans of African ancestry but not European. Overall, we observed a shared genetic architecture between COVID-19 severity and conditions related to underlying risk factors for severe and poor COVID-19 outcomes. Differing associations between genotype-phenotype across ancestries may inform heterogenous outcomes observed with COVID-19. Divergent associations between risk for severe COVID-19 with autoimmune inflammatory conditions both respiratory and non-respiratory highlights the shared pathways and fine balance of immune host response and autoimmunity and caution required when considering treatment targets.

Hematopoietic mosaic chromosomal alterations and risk for infection among 767,891 individuals without blood cancer (preprint)

Age is the dominant risk factor for infectious diseases, but the mechanisms linking the two are incompletely understood1,2. Age-related mosaic chromosomal alterations (mCAs) detected from blood-derived DNA genotyping, are structural somatic variants associated with aberrant leukocyte cell counts, hematological malignancy, and mortality3-11. Whether mCAs represent independent risk factors for infection is unknown. Here we use genome-wide genotyping of blood DNA to show that mCAs predispose to diverse infectious diseases. We analyzed mCAs from 767,891 individuals without hematological cancer at DNA acquisition across four countries. Expanded mCA (cell fraction >10%) prevalence approached 4% by 60 years of age and was associated with diverse incident infections, including sepsis, pneumonia, and coronavirus disease 2019 (COVID-19) hospitalization. A genome-wide association study of expanded mCAs identified 63 significant loci. Germline genetic alleles associated with expanded mCAs were enriched at transcriptional regulatory sites for immune cells. Our results link mCAs with impaired immunity and predisposition to infections. Furthermore, these findings may also have important implications for the ongoing COVID-19 pandemic, particularly in prioritizing individual preventive strategies and evaluating immunization responses.

Single-Cell Omics Reveals Dyssynchrony of the Innate and Adaptive Immune System in Progressive COVID-19 (preprint)

A dysregulated immune response against the SARS-CoV-2 virus plays a critical role in severe COVID-19. However, the molecular and cellular mechanisms by which the virus causes lethal immunopathology are poorly understood. Here, we utilize multi-omics single-cell analysis to probe dynamic immune responses in patients with stable or progressive manifestations of COVID-19, and assess the effects of tocilizumab, an anti-IL-6 receptor monoclonal antibody. Coordinated profiling of gene expression and cell lineage protein markers reveals a prominent type-1 interferon response across all immune cells, especially in progressive patients. An anti-inflammatory innate immune response and a pre-exhaustion phenotype in activated T cells are hallmarks of progressive disease. Skewed T cell receptor repertoires in CD8 T cells and uniquely enriched V(D)J sequences are also identified in COVID-19 patients. B cell repertoire and somatic hypermutation analysis are consistent with a primary immune response, with possible contribution from memory B cells. Our in-depth immune profiling reveals dyssynchrony of the innate and adaptive immune interaction in progressive COVID-19, which may contribute to delayed virus clearance and has implications for therapeutic intervention.

Androgen regulates SARS-CoV-2 receptor levels and is associated with severe COVID-19 symptoms in men (preprint)

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has led to a global health crisis, and yet our understanding of the disease pathophysiology and potential treatment options remains limited. SARS-CoV-2 infection occurs through binding and internalization of the viral spike protein to angiotensin converting enzyme 2 (ACE2) on the host cell membrane. Lethal complications are caused by damage and failure of vital organs that express high levels of ACE2, including the lungs, the heart and the kidneys. Here, we established a high-throughput drug screening strategy to identify therapeutic candidates that reduce ACE2 levels in human embryonic stem cell (hESC) derived cardiac cells. Drug target analysis of validated hit compounds, including 5 alpha reductase inhibitors, revealed androgen signaling as a key modulator of ACE2 levels. Treatment with the 5 alpha reductase inhibitor dutasteride reduced ACE2 levels and internalization of recombinant spike receptor binding domain (Spike-RBD) in hESC-derived cardiac cells and human alveolar epithelial cells. Finally, clinical data on coronavirus disease 2019 (COVID-19) patients demonstrated that abnormal androgen states are significantly associated with severe disease complications and cardiac injury as measured by blood troponin T levels. These findings provide important insights on the mechanism of increased disease susceptibility in male COVID-19 patients and identify androgen receptor inhibition as a potential therapeutic strategy.

Influence of blood pressure on pneumonia risk: Epidemiological association and Mendelian randomisation in the UK Biobank (preprint)

Objectives To determine whether elevated blood pressure influences risk for respiratory infection. Design Prospective, population-based epidemiological and Mendelian randomisation studies. Setting UK Biobank. Participants 377,143 self-identified British descent (54% women; median age 58 years) participants in the UK Biobank. Main outcome measures First incident pneumonia over an average of 8 follow-up years. Results 107,310 (30%) participants had hypertension at UK Biobank enrolment, and 9,969 (3%) developed a pneumonia during follow-up. Prevalent hypertension at baseline was significantly associated with increased risk for incident respiratory disease including pneumonia (hazard ratio 1.36 (95% confidence interval 1.29 to 1.43), P<0.001), acute respiratory distress syndrome or respiratory failure (1.43 (1.29 to 1.59), P<0.001), and chronic lower respiratory disease (1.30 (1.25 to 1.36), P<0.001), independent of age, age 2 , sex, smoking status, BMI, prevalent diabetes mellitus, prevalent coronary artery disease, and principal components of ancestry. Mendelian randomisation analyses indicated that genetic predisposition to a 5 mmHg increase in blood pressure was associated with increased risk of incident pneumonia for SBP (1.08, (1.04 to 1.13), P<0.001) and DBP (1.11 (1.03 to 1.20), P=0.005). Additionally, consistent with epidemiologic associations, increase in blood pressure genetic risk was significantly associated with reduced forced expiratory volume in the first second, forced vital capacity, and the ratio of the two (P<0.001 for all). Conclusions These results strongly suggest that elevated blood pressure independently increases risk for pneumonia and reduces pulmonary function. Maintaining adequate blood pressure control, in addition to other measures, may reduce risk for pneumonia. Whether the present findings are generalizable to novel coronavirus disease 2019 (COVID-19) require further study. Summary Box Section 1: What is already known on this topic Hypertension has been associated with pneumonia in small observational studies. Based on early epidemiologic analyses, hypertension is described as a risk factor for SARS-CoV-2 infection and associated novel coronavirus disease 2019 (COVID-19). The influence of hypertension on pneumonia risk is difficult to assess in traditional observational studies. Section 2: What this study adds Our pre-COVID-19 analyses are consistent with a causal relationship between increased blood pressure and increased risk for incident respiratory infections, as well as between increased blood pressure and reduced pulmonary function. These results support hypertension as a pneumonia risk factor; efforts to optimize blood pressure may reduce risk for pneumonia.