Targeting G9a translational mechanism of SARS-CoV-2 pathogenesis for multifaceted therapeutics of COVID-19 and its sequalae (preprint)

By largely unknown mechanism(s), SARS-CoV-2 hijacks the host translation apparatus to promote COVID-19 pathogenesis. We report that the histone methyltransferase G9a noncanonically regulates viral hijacking of the translation machinery to bring about COVID-19 symptoms of hyperinflammation, lymphopenia, and blood coagulation. Chemoproteomic analysis of COVID-19 patient peripheral mononuclear blood cells (PBMC) identified enhanced interactions between SARS-CoV-2-upregulated G9a and distinct translation regulators, particularly the N6-methyladenosine (m6A) RNA methylase METTL3. These interactions with translation regulators implicated G9a in translational regulation of COVID-19. Inhibition of G9a activity suppressed SARS-CoV-2 replication in human alveolar epithelial cells. Accordingly, multi-omics analysis of the same alveolar cells identified SARS-CoV-2-induced changes at the transcriptional, m6A-epitranscriptional, translational, and post-translational (phosphorylation or secretion) levels that were reversed by inhibitor treatment. As suggested by the aforesaid chemoproteomic analysis, these multi-omics-correlated changes revealed a G9a-regulated translational mechanism of COVID-19 pathogenesis in which G9a directs translation of viral and host proteins associated with SARS-CoV-2 replication and with dysregulation of host response. Comparison of proteomic analyses of G9a inhibitor-treated, SARS-CoV-2 infected cells, or ex vivo culture of patient PBMCs, with COVID-19 patient data revealed that G9a inhibition reversed the patient proteomic landscape that correlated with COVID-19 pathology/symptoms. These data also indicated that the G9a-regulated, inhibitor-reversed, translational mechanism outperformed G9a-transcriptional suppression to ultimately determine COVID-19 pathogenesis and to define the inhibitor action, from which biomarkers of serve symptom vulnerability were mechanistically derived. This cell line-to-patient conservation of G9a-translated, COVID-19 proteome suggests that G9a inhibitors can be used to treat patients with COVID-19, particularly patients with long-lasting COVID-19 sequelae.

TISSUE-SPECIFIC METABOLOMIC REPROGRAMMING DETERMINES THE DISEASE PATHOPHYSIOLOGY OF SARS-COV-2 VARIANTS IN HAMSTER MODEL (preprint)

Despite significant effort, a clear understanding of host tissue-specific responses and their implications for immunopathogenicity against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant infection has remained poorly defined. To shed light on the interaction between organs and specific SARS-CoV-2 variants, we sought to characterize the complex relationship among acute multisystem manifestations, dysbiosis of the gut microbiota, and the resulting implications for SARS-CoV-2 variant-specific immunopathogenesis in the Golden Syrian Hamster (GSH) model using multi-omics approaches. Our investigation revealed increased viremia in diverse tissues of delta-infected GSH compared to the omicron variant. Multi-omics analyses uncovered distinctive metabolic responses between the delta and omicron variants, with the former demonstrating dysregulation in synaptic transmission proteins associated with neurocognitive disorders. Additionally, delta-infected GSH exhibited an altered fecal microbiota composition, marked by increased inflammation-associated taxa and reduced commensal bacteria compared to the omicron variant. These findings underscore the SARS-CoV-2-mediated tissue insult, characterized by modified host metabolites, neurological protein dysregulation, and gut dysbiosis, highlighting the compromised gut-lung-brain axis during acute infection.

Sex-Specific Systemic Inflammatory Responses in Mice Infected with a SARS-CoV-2-like Virus and Femur Fracture (preprint)

This study investigates the systemic inflammatory response in mice infected with a murine coronavirus (MHV), which shares a common genus with SARS-CoV-2, and sustaining a fracture. The study reveals that the combined inflammatory incidents of MHV infection and fracture disrupt the systemic immune response in both female and male mice, likely leading to immune dysregulation, altered cell recruitment, and disruption of the typical inflammatory cascade. Notably, the study uncovers sex-specific responses that modulate circulating immune factors. Females exhibit elevated levels of inflammatory factors, whereas males demonstrate a diminished response. This divergence is mirrored in cell populations, suggesting that the quantity of immune factors released may contribute to these discrepancies. The findings suggest that an overproduction of proinflammatory cytokines may induce a dysregulated immune response, contributing to the observed poorer prognosis in comorbid cases. These insights could pave the way for therapeutic advancements and treatment strategies aimed at reducing mortality rates in COVID-19 patients with fractures.

Modulation of human kinase activity through direct interaction with SARS-CoV-2 proteins (preprint)

The dysregulation of cellular signaling upon SARS-CoV-2 infection is mediated via direct protein interactions, with the human protein kinases constituting the major impact nodes in the signaling networks. Here, we employed a targeted yeast two-hybrid matrix approach to identify direct SARS-CoV-2 protein interactions with an extensive set of human kinases. We discovered 51 interactions involving 14 SARS-CoV-2 proteins and 29 human kinases, including many of the CAMK and CMGC kinase family members, as well as non-receptor tyrosine kinases. By integrating the interactions identified in our screen with transcriptomics and phospho-proteomics data, we revealed connections between SARS-CoV-2 protein interactions, kinase activity changes, and the cellular phospho-response to infection and identified altered activity patterns in infected cells for AURKB, CDK2, CDK4, CDK7, ABL2, PIM2, PLK1, NEK2, TRIB3, RIPK2, MAPK13, and MAPK14. Finally, we demonstrated direct inhibition of the FER human tyrosine kinase by the SARS-CoV-2 auxiliary protein ORF6, hinting at pressures underlying ORF6 changes observed in recent SARS-CoV-2 strains. Our study expands the SARS-CoV-2 - host interaction knowledge, illuminating the critical role of dysregulated kinase signaling during SARS-CoV-2 infection.

Altered DNA methylation underlies monocyte dysregulation and innate exhaustion memory in sepsis (preprint)

Innate immune memory is the process by which pathogen exposure elicits cell-intrinsic states to alter the strength of future immune challenges. Such altered memory states drive monocyte dysregulation during sepsis, promoting pathogenic behavior characterized by pro-inflammatory, immunosuppressive gene expression in concert with emergency hematopoiesis. Epigenetic changes, notably in the form of histone modifications, have been shown to underlie innate immune memory, but the contribution of DNA methylation to this process remains poorly understood. Using an ex vivo sepsis model, we discovered broad changes in DNA methylation throughout the genome of exhausted monocytes, including at several genes previously implicated as major drivers of immune dysregulation during sepsis and Covid-19 infection (e.g. Plac8). Methylome alterations are driven in part by Wnt signaling inhibition in exhausted monocytes, and can be reversed through treatment with DNA methyltransferase inhibitors, Wnt agonists, or immune training molecules. Importantly, these changes are recapitulated in septic mice following cecal slurry injection, resulting in stable changes at critical immune genes that support the involvement of DNA methylation in acute and long-term monocyte dysregulation during sepsis.

Improvement of immune dysregulation and health-related quality of life in individuals with long COVID at 24-months following SARS-CoV-2 infection (preprint)

This study investigated the humoral and cellular immune responses in individuals with long COVID (LC) compared to age and gender matched recovered COVID-19 controls (MC) over 24-months. LC participants showed elevated spike and nucleocapsid IgG levels, higher neutralizing capacity, and increased spike- and nucleocapsid-specific CD4+ T cells, PD-1, and TIM-3 expression on CD4+ and CD8+ T cells at 3- and 8-months, but these differences did not persist at 24-months. Some LC participants had detectable IFN-{beta} and IFN-{gamma} that was attributed to reinfection and antigen re-exposure. Single-cell RNA sequencing at 24-month timepoint revealed similar immune cell proportions and reconstitution of naive T and B cell subsets in LC. No significant differences in exhaustion scores or antigen-specific T cell clones were observed. These findings suggest resolution of immune activation in LC and return to comparable immune responses between LC and MC over time. Improvement in self-reported health-related quality of life at 24-months was also evident in the majority of LC (62%). PTX3, CRP levels and platelet count were associated with improvements in health-related quality of life.

The Human Microglia Atlas (HuMicA) Unravels Changes in Homeostatic and Disease-Associated Microglia Subsets across Neurodegenerative Conditions (preprint)

Dysregulated microglia activation, leading to neuroinflammation, is currently considered to be of major relevance in the development and progression of neurodegenerative diseases. The initial M1/M2 dual activation classification for microglia is now considered outdated. Even the "disease-associated microglia" (DAM) phenotype, firstly described in mice, has proven insufficient to precisely represent the multitude of microglia phenotypes in pathology. In this study, we have constructed a transcriptomic atlas of human brain immune cells by integrating single-nucleus (sn)RNA-seq datasets from multiple neurodegenerative conditions. Sixteen datasets were included, comprising 295 samples from patients with Alzheimer's disease, autism spectrum disorder, epilepsy, multiple sclerosis, Lewy body diseases, COVID-19, and healthy controls. The integrated Human Microglia Atlas (HuMicA) dataset included 60,557 nuclei and revealed 11 microglial subpopulations distributed across all pathological and healthy conditions. Among these, we identified four different homeostatic clusters as well as pathological phenotypes. These included two stages of early and late activation of the DAM phenotype and the disease-inflammatory macrophage (DIM) phenotype, which was recently described in mice, and is also present in human microglia, as indicated by our analysis. The high versatility of microglia is evident through changes in subset distribution across various pathologies, suggesting their contribution to the establishment of pathological phenotypes. Our analysis showed overall depletion of four substates of homeostatic microglia, and expansion of niche subpopulations within the DAM and DIM spectrum across distinct neurodegenerative pathologies. The HuMicA is an invaluable resource tool used to support further advances in the study of microglia biology through healthy and disease settings.

Multimodal Molecular Imaging Reveals Tissue-Based T Cell Activation and Viral RNA Persistence for Up to Two Years Following COVID-19 (preprint)

The etiologic mechanisms of post-acute medical morbidities and unexplained symptoms (Long COVID) following SARS-CoV-2 infection are incompletely understood. There is growing evidence that viral persistence and immune dysregulation may play a major role. We performed whole-body positron emission tomography (PET) imaging in a cohort of 24 participants at time points ranging from 27 to 910 days following acute SARS-CoV-2 infection using a novel radiopharmaceutical agent, [18F]F-AraG, a highly selective tracer that allows for anatomical quantitation of activated T lymphocytes. Tracer uptake in the post-acute COVID group, which included those with and without Long COVID symptoms, was significantly higher compared to pre-pandemic controls in many anatomical regions, including the brain stem, spinal cord, bone marrow, nasopharyngeal and hilar lymphoid tissue, cardiopulmonary tissues, and gut wall. Although T cell activation tended to be higher in participants imaged closer to the time of the acute illness, tracer uptake was increased in participants imaged up to 2.5 years following SARS-CoV-2 infection. We observed that T cell activation in spinal cord and gut wall was associated with the presence of Long COVID symptoms. In addition, tracer uptake in lung tissue was higher in those with persistent pulmonary symptoms. Notably, increased T cell activation in these tissues was also observed in many individuals without Long COVID. Given the high [18F]F-AraG uptake detected in the gut, we obtained colorectal tissue for in situ hybridization SARS-CoV-2 RNA and immunohistochemical studies in a subset of participants with Long COVID symptoms. We identified cellular SARS-CoV-2 RNA in rectosigmoid lamina propria tissue in all these participants, ranging from 158 to 676 days following initial COVID-19 illness, suggesting that tissue viral persistence could be associated with long-term immunological perturbations.

Carotid body dysregulation contributes to the enigma of long COVID (preprint)

The symptoms of long COVID, which include fatigue, breathlessness, dysregulated breathing, and exercise intolerance, have unknown mechanisms. These symptoms are also observed in heart failure and are partially driven by increased sensitivity of the carotid chemoreflex. As the carotid body has an abundance of ACE2 (the cell entry mechanism for SARS-CoV-2), we investigated whether carotid chemoreflex sensitivity was elevated in participants with long COVID. During cardiopulmonary exercise testing, the VE/VCO2 slope (a measure of breathing efficiency) was higher in the long COVID group than in the controls, indicating excessive hyperventilation. The hypoxic ventilatory response, which measures carotid chemoreflex sensitivity, was increased in long COVID participants and correlated with the VE/VCO2 slope, suggesting that excessive hyperventilation may be related to carotid body hypersensitivity. Therefore, the carotid chemoreflex is sensitized in long COVID and may explain dysregulated breathing and exercise intolerance in these participants. Tempering carotid body excitability may be a viable treatment option for long COVID patients.

Antibodies against SARS-CoV-2 control complement-induced inflammatory responses to SARS-CoV-2 (preprint)

Dysregulated immune responses contribute to pathogenesis of COVID-19 leading to uncontrolled and exaggerated inflammation observed during severe COVID-19. However, it remains unclear how immunity to SARS-CoV-2 is induced and subsequently controlled. Notably, here we have uncovered an important role for complement in the induction of innate and adaptive immunity to SARS-CoV-2. Complement rapidly opsonized SARS-CoV-2 via the lectin pathway. Complement-opsonized SARS-CoV-2 efficiently interacted with dendritic cells (DCs), inducing type I IFN and pro-inflammatory cytokine responses, which were inhibited by antibodies against the complement receptors (CR)3 and CR4. These data suggest that complement is important in inducing immunity via DCs in the acute phase against SARS-CoV-2. Strikingly, serum from COVID-19 patients as well as monoclonal antibodies against SARS-CoV-2 attenuated innate and adaptive immunity induced by complement-opsonized SARS-CoV-2. Blocking the FcyRII, CD32, restored complement-induced immunity. These data strongly suggest that complement opsonization of SARS-CoV-2 is important for inducing innate and adaptive immunity to SARS-CoV-2. Subsequent induction of antibody responses is important to limit the immune responses and restore immune homeostasis. These data suggest that dysregulation in complement and FcyRII signalling might underlie mechanisms causing severe COVID-19.

ACE2, ACE, DPPIV, PREP and CAT L enzymatic activities in COVID-19: imbalance of ACE2/ACE ratio and potential RAS dysregulation in severe cases (preprint)

Objective and design: Several proteases have drawn attention as potential targets to control the SARS-CoV-2 infection (COVID-19), thus circulating enzymatic activity and RAS regulation in severe hospitalized patients still remain to be determined. Material or subjects: 164 patients with COVID-19-like symptoms were grouped according to the severity of symptoms (COVID-19 negative, mild, moderate and severe). Methods: Patients were subjected to biochemical analyzes and to enzymatic activities of ACE2, ACE, DPPIV, PREP and CAT L, evaluated in serum samples. One-way ANOVA and multivariate logistic regression analysis were used. Statistical significance was accepted at p<0.05. Results: We show a correlation among comorbidities, elevated C-reactive protein (CRP) levels and disease severity. Additionally, concomitant high levels of D-dimer and CRP could be as prognostic for severe conditions. Assays of enzymatic activities revealed that, according to disease severity, both ACE2 and CAT L were statistically increased, while ACE, DPPIV and PREP activities were significantly reduced. Notably, analysis of ACE2/ACE ratio suggest a possible imbalance of Ang II/Ang1-7 ratio in severe patients. Conclusion: Our findings reveal the correlation between protease activity and the severity of COVID-19, in addition to highlighting the imbalance of ACE2/ACE ratio, predicting RAS dysregulation, closely related with a poor outcome of disease.

The Renin-Angiotensin-System in COVID-19: Can Long COVID Be Predicted? (preprint)

(1) Background: Co-morbidities such as hypertension and cardiovascular disease are major risk factors for severe COVID-19. The renin-angiotensin-system (RAS) is critically involved in their pathophysiology and is counterbalanced by both angiotensin-converting enzyme 2 (ACE2), the functional receptor of SARS-CoV-2, and the kallikrein-kinin-system (KKS). Considerable research interest with respect to COVID-19 treatment is, thus, currently directed towards the components of these systems. In an earlier study, we noticed significantly reduced carboxypeptidase N (CPN, KKS member) activity and partially excessive angiotensin-converting enzyme (ACE, RAS member) activity in the sera of both hospitalized (HoP) COVID-19 patients and a sub-group of covalescent patients, while in the majority of the probands recovering from the disease these values had returned to normal. The data had been obtained using bradykinin (BK) as a reporter peptide, which is a target of both CPN and ACE, and they were supplemented by serum proteomics of the same patient cohort. We hypothesized that the data could be indicative of Long COVID, which had not been fully appreciated at the time of our study.; (2) Methods: The data were re-evaluated in the light of Long COVID. The recent literature on the RAS in COVID-19, antihypertensiva, and Long COVID was briefly reviewed.; (3) Results: While the levels of the BK serum degradation products should return to normal concentrations during convalescence, this was not true for some patients. This could be due to persisting liver problems, because CPN is synthesized there, but also to a dysregulated RAS. This was not reflected in the levels of selected RAS/KKS serum proteins like angiotensinogen (AGT), although AGT correlated with disease severity in HoP. However, standard tests in routine patient care in Long COVID often come back normal, and it may be that BK degradation is specific in some pathophysiologies. Moreover, the HoP group was sub-divided based on the serum protein profiles and COVID-19 severity.; (4) Conclusions: We point out two insights: 1) Sensitive technology such as omics methods might provide unexpected significant differences within the pre-defined patient groups of a clinical study. Those can only be explored, if the cohorts are large enough and properly matched with respect to the parameters known beforehand (e.g., age, gender, co-morbidities). 2) Results of the BK-reporter serum protease activity assay could be indicative of persisting liver problems and/or potentially of Long COVID. Clinical studies are required to test this hypothesis.

Identification of six genes associated with COVID-19-related Circadian rhythm dysfunction by integrated bioinformatic analysis (preprint)

Background Patients with coronavirus disease 2019 (COVID-19) might cause long-term burden of insomnia, while the common pathogenic mechanisms are not elucidated.Methods The gene expression profiles of COVID-19 patients and healthy controls were retrieved from the GEO database, while gene set related with circadian rhythm were obtained from Genecards database. The weight gene co-expression network analysis (WGCNA) algorithms were conducted to identify the most correlated gene module with COVID-19. Functional enrichment analysis and protein-protein interaction network (PPI) were performed on shared genes between key module and circadian rhythm gene set. Hub genes were identified and gene regulatory networks, immune cell Infiltration evaluation and Drug–Gene interaction were constructed.Results 76 shared genes were screened and mainly enriched in cell cycle, cell division and cell proliferation, and 6 hub genes were found out including CCNA2, CCNB1, CDK1, CHEK1, MKI67 and TOP2A, with positive correlation to plasma cells. In the TF-gene regulatory network, NFYA, NFIC, MEF2A and FOXC1 showed high connectivity with hub genes.Conclusions This study established the co-expression network and identified six hub genes, which might provide new insights into pathogenic mechanisms and novel clinical management strategies.

The plasma metabolome of long COVID-19 patients two years after infection (preprint)

Background: One of the major challenges currently faced by global health systems is the prolonged COVID-19 syndrome (also known as long COVID) which has emerged as a consequence of the SARS-CoV-2 epidemic. The World Health Organization (WHO) recognized long COVID as a distinct clinical entity in 2021. It is estimated that at least 30% of patients who have had COVID-19 will develop long COVID. This has put a tremendous strain on still-overstretched healthcare systems around the world. Methods: In this study, our goal was to assess the plasma metabolome in a total of 108 samples collected from healthy controls, COVID-19 patients, and long COVID patients recruited in Mexico between 2020 and 2022. A targeted metabolomics approach using a combination of LC-MS/MS and FIA MS/MS was performed to quantify 108 metabolites. IL-17 and leptin concentrations were measured in long COVID patients by immunoenzymatic assay. Results: The comparison of paired COVID-19/post-COVID-19 samples revealed 53 metabolites that were statistically different (FDR < 0.05). Compared to controls, 29 metabolites remained dysregulated even after two years. Notably, glucose, kynurenine, and certain acylcarnitines continued to exhibit altered concentrations similar to the COVID-19 phase, while sphingomyelins and long saturated and monounsaturated LysoPCs, phenylalanine, butyric acid, and propionic acid levels normalized. Post-COVID-19 patients displayed a heterogeneous metabolic profile, with some showing no symptoms while others exhibiting a variable number of symptoms. Lactic acid, lactate/pyruvate ratio, ornithine/citrulline ratio, sarcosine, and arginine were identified as the most relevant metabolites for distinguishing patients with more complicated long COVID evolution. Additionally, IL-17 levels were significantly increased in these patients. Conclusions: Mitochondrial dysfunction, redox state imbalance, impaired energy metabolism, and chronic immune dysregulation are likely to be the main hallmarks of long COVID even two years after acute COVID-19 infection.

Integrated NMR and MS analysis of plasma metabolome reveals major changes in inflammatory markers, one-carbon, lipid, and amino acid metabolism in severe and fatal COVID-19 subjects (preprint)

Brazil has the second highest COVID-19 death rate while Rio de Janeiro is among the states with the highest rate in the country. Although effective vaccines have been developed, it is anticipated that the ongoing COVID-19 pandemic will transition into an endemic state. Under this scenario, it is worrisome that the underlying molecular mechanisms associated with the disease clinical evolution from mild to severe, as well as the mechanisms leading to long COVID are not yet fully understood. In this study, 1H Nuclear Magnetic Resonance spectroscopy and Liquid Chromatography-Mass spectrometry-based metabolomics were used to identify potential pathways and metabolites involved in COVID-19 pathophysiology and disease outcome. Between April and July 2020, 35 plasma samples from patients with confirmed severe COVID-19 from two reference centers in Rio de Janeiro, and 12 samples from non-infected control subjects, were collected and included in this study. Of the 35 samples from COVID-19 patients, 18 were from survivors and 17 from non-survivors. We observed that patients with severe COVID-19 had their plasma metabolome significantly changed if compared to control subjects. We observed lower levels of glycerophosphocholine and other choline-related metabolites, serine, glycine, and betaine, indicating a dysregulation in methyl donors and one-carbon metabolism. Importantly, non-survivors had higher levels of creatine/creatinine, 4-hydroxyproline, gluconic acid and N-acetylserine compared to survivors and controls, reflecting uncontrolled inflammation, liver and kidney dysfunction, and insulin resistance in these patients. Lipoprotein dynamics and amino acid metabolism were also altered in severe COVID-19 subjects. Several changes were greater in women, thus patient's sex should be considered in pandemic surveillance to achieve better disease stratification and improve outcomes. The incidence of severe outcome after hospital discharge is very high in Brazil, thus these metabolic alterations may be used to monitor patients' organs and tissues and to understand the pathophysiology of long-post COVID-19.

Treatment of long COVID complicated by postural orthostatic tachycardia syndrome (preprint)

Purpose The coronavirus disease sequelae, known as long coronavirus disease may present with various symptoms. Among these symptoms, autonomic dysregulation, especially postural orthostatic tachycardia syndrome, should be evaluated. This study aimed to investigate the treatment course of long coronavirus disease, with postural orthostatic tachycardia syndrome.Methods The medical records of patients who complained of fatigue and met the criteria for postural orthostatic tachycardia syndrome diagnosis were reviewed. Change in heart rate fatigue score, and employment/education status at the initial and last visits were evaluated.Results Thirty-two patients with long coronavirus disease complicated by postural orthostatic tachycardia syndrome were followed up (16 male and 16 female; median age: 28 years). Three patients had acute-phase pneumonia. The follow-up period was 159 days, and the interval between coronavirus disease onset and initial hospital attendance was 97 days. Some patients responded to beta-blocker therapy. Many patients had psychiatric symptoms that required psychiatric intervention and selective serotonin reuptake inhibitor prescription. Difference in heart rate and performance status, and employment/education status improved from the first to the last clinic visit. Postural orthostatic tachycardia syndrome after severe acute respiratory syndrome coronavirus 2 infection could be treated faster than the syndrome occurring in isolation. This was thought to be due to the effects of various treatment interventions and spontaneous improvements after severe acute respiratory syndrome coronavirus 2 infection.Conclusion Postural orthostatic tachycardia syndrome evaluation must be considered when patients with symptoms of coronavirus disease complain of fatigue.

GATA1 Knockout in Human Pluripotent Stem Cells Generates Enhanced Neutrophils to Investigate Extracellular Trap Formation (preprint)

Human pluripotent stem cell (hPSC)-derived tissues can be used to model diseases and validate targets in cell types that are challenging to harvest and study at scale, such as neutrophils. Neutrophil dysregulation, specifically unbalanced neutrophil extracellular trap (NET) formation, plays a critical role in the prognosis and progression of multiple diseases, including COVID-19. hPSCs can provide a limitless supply of neutrophils (iNeutrophils) to study these processes and discover and validate targets in vitro. However, current iNeutrophil differentiation protocols are inefficient and generate heterogeneous cultures consisting of different granulocytes and precursors, which can confound the study of neutrophil biology. Here, we describe a method to dramatically improve iNeutrophils′ yield, purity, functionality, and maturity through the deletion of the transcription factor GATA1. GATA1 knockout (KO) iNeutrophils are nearly identical to primary neutrophils in cell surface marker expression, morphology, and host defense functions. Unlike wild type (WT) iNeutrophils, GATA1 KO iNeutrophils generate NETs in response to the physiologic stimulant lipopolysaccharide (LPS), suggesting they could be used as a more accurate model when performing small-molecule screens to find NET inhibitors. Furthermore, through CRSPR/Cas9 deletion of CYBB we demonstrate that GATA1 KO iNeutrophils are a powerful tool in quickly and definitively determining involvement of a given protein in NET formation.

Longitudinal plasma proteomics reveals alveolar-capillary barrier disruption in critically ill COVID-19 patients (preprint)

The pathobiology of respiratory failure in COVID-19 consists of a complex interplay between direct viral cytopathic effects and a dysregulated host immune response. In a randomised clinical trial, imatinib treatment improved clinical outcomes associated with respiratory failure. Here, we performed longitudinal profiling of 6385 plasma proteins in 318 hospitalised patients to investigate the biological processes involved in critical COVID-19, and assess the effects of imatinib treatment. Nine proteins measured at hospital admission accurately predicted critical illness development. Next to dysregulation of inflammation, critical illness was characterised by pathways involving cellular adhesion, extracellular matrix turnover and tissue remodelling. Imatinib treatment attenuated protein perturbations associated with inflammation and extracellular matrix turnover. External RNA-sequencing data from the lungs of SARS-CoV-2 infected hamsters validated that imatinib exerts these effects in the pulmonary compartment. These findings implicate that the plasma proteome reflects alveolar capillary barrier disruption in critical COVID-19 which was attenuated with imatinib treatment.

COVID-associated complications after reconstructive breast surgery – a retrospective cohort study (preprint)

Purpose. The COVID pandemic significantly influenced reconstructive breast surgery regimens. Many surgeries were cancelled or postponed. COVID entails not only respiratory, but also coagulative symptoms. It therefore potentially increases the risk of postoperative complications. The incidence of perioperative COVID infection and its influence on postoperative recovery after reconstructive breast surgery is still unknown.Methods. This dual center retrospective cohort study included patients that underwent reconstructive breast surgery between March 2020 and July 2021. Post-mastectomy autologous or implant-based breast reconstruction (ABR; IBR), as well as post-lumpectomy oncoplastic partial breast reconstruction (PBR) were eligible. Patient data was extracted from electronic medical records. Data regarding COVID-19 infection was collected through a questionnaire. The primary outcome was complication rate.Results. The ABR, IBR and PBR groups consisted of 113 (12 COVID-positive), 41 (2 COVID-positive) and 113 (10 COVID-positive) patients. In the ABR and PBR groups, postoperative complications occurred significantly more often in patients with perioperative COVID-infection. Especially impaired wound healing occurred significantly more often in the ABR and PBR breasts, but also at the donor site of ABR patients with perioperative COVID.Conclusion. Perioperative COVID-infection increases susceptibility to complicated wound healing after reconstructive breast surgery. A possible explanation lies in the dysregulation of haemostasis by the virus, and its direct effects on microvasculature. A hypercoagulable state results. We recommend to postpone elective breast surgery for 4–6 weeks after COVID-19 infection. Also, precautionary measures remain important to minimize the risk of perioperative COVID-19 infection.

Comparative Cohort Study of Post-Acute Covid-19 Infection with a Nested, Randomized Controlled Trial of Ivabradine for Those With Postural Orthostatic Tachycardia Syndrome (The COVIVA Study) (preprint)

Background: Significant clinical similarities have been observed between the recently described Long-Haul COVID-19 (LHC) syndrome, Postural Orthostatic Tachycardia Syndrome (POTS) and Inappropriate Sinus Tachycardia (IST). Shared symptoms include light-headedness, palpitations, tremulousness, generalized weakness, blurred vision, chest pain, dyspnea, brain-fog, and fatigue. Ivabradine is a selective sinoatrial node blocker FDA-approved for management of tachycardia associated with stable angina and heart failure not fully managed by beta blockers. In our study we aim to identify risk factors underlying LHC, as well as the effectiveness of ivabradine in controlling heart rate dysregulations and POTS/IST related symptoms. Methods/Design: A detailed prospective phenotypic evaluation combined with multi-omic analysis of 200 LHC volunteers will be conducted to identify risk factors for autonomic dysfunction. A comparator group of 50 volunteers with documented COVID-19 but without LHC will be enrolled to better understand the risk factors for LHC and autonomic dysfunction. Those in the cohort who meet diagnostic criteria for POTS or IST will be included in a nested prospective, randomized, placebo-controlled trial to assess the impact of ivabradine on symptoms and heart rate, assessed non-invasively based on physiologic response and ambulatory electrocardiogram. Additionally, studies on catecholamine production, mast cell and basophil degranulation, inflammatory biomarkers, and indicators of metabolic dysfunction will be measured to potentially provide molecular classification and mechanistic insights. Discussion: Optimal therapies for dysautonomia, particularly associated with LHC, have yet to be defined. In the present study, ivabradine, one of numerous proposed interventions, will be systematically evaluated for therapeutic potential in LHC-associated POTS and IST. Additionally, this study will further refine the characteristics of the LHC-associated POTS/IST phenotype, genotype and transcriptional profile, including immunologic and multi-omic analysis of persistent immune activation and dysregulation. The study will also explore and identify potential endotheliopathy and abnormalities of the clotting cascade.