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Myocardial infarction is a global health burden for which there is no treatment available that aims to recover the damaged tissue after the ischemic event. Lipid nanoparticles (LNPs) represent a well characterized class of mRNA delivery systems, which were recently approved for clinical usage in their application for mRNA-based covid-19 vaccines. After myocardial infarction, endogenous mechanisms that enable repair of the functional damaged tissue can be triggered by modified mRNA (modRNA) delivery, locally in the infarcted area. As a first step, in order to optimize the LNP formulation for effective myocardial delivery and study cellular tropism of the LNPs in the heart, different LNPs formulations will be evaluated as delivery systems in a murine healthy heart model. Different LNP formulations varying in type and amount of helper lipid were used as delivery systems for modRNA encoding the reporter genes luciferase or eGFP. In vitro, LNPs were evaluated for modRNA delivery in a human endothelial cell line (HMEC-1), induced pluripotent stem cell-derived cardiomyocytes (iPS-CMs) and induced pluripotent stem cell -derived fibroblasts (iPS-FBs). In vivo, modRNA delivery was evaluated in C57BL-6 mice, undergoing open chest heart surgery under general anaesthesia in order to infuse LNPs into the left ventricular wall. For determination of luciferase expression levels, animals were infused with luciferin substrate intraperitoneally 24 hrs after injection. Heart, liver, lungs, spleen and kidneys were extracted for imaging in a bioluminescence imaging system. The organs were then stored in liquid nitrogen for further ex-vivo modRNA delivery analysis. For determining cellular tropism, histology was performed on mice treated with eGFP modRNA. Both bioluminescence imaging and luminescence analysis in tissue lysates showed that mRNA transfection is achieved in the myocardium 24 hours after LNP intramyocardial administration. However, all LNP formulations also resulted in high expression levels in other organs, including liver and spleen. Changes in type or amount of helper lipid in LNPs strongly affected transfection levels. Histology of the treated hearts revealed a distinct transfection pattern. The targeted, interstitial cells were negative for CD31 (marker for endothelial cells and monocytes) and Troponin I3 (marker for cardiomyocytes) (Figure 1). We show that, using an optimized LNP formulation, a significant degree of modRNA local transfection of the heart can be achieved. However, despite the local route of administration (into the left ventricular wall), the highest LNP transfection is shown in remote organs such as liver and spleen. More improvements of the LNP formulations must be done to increase their tropism towards the heart tissue for their optimization as cardiac delivery systems. Determining which cell types are being targeted is also important in order to establish a therapeutic target when applying the LNPs for cardiac therapy. (Figure Presented).
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Rationale: Recent advancements in sequencing technologies have led to a substantial increase in the scale and resolution of transcriptomic data. Despite this progress, accessibility to this data, particularly among those who are coming from non-computational backgrounds is limited. To facilitate improved access and exploration of our single-cell RNA sequencing data, we generated several data sharing, mining and dissemination portals to accompany our idiopathic pulmonary fibrosis (IPF), chronic obstructive pulmonary disease (COPD), and lung endothelial cells (Lung EC) cell atlases. Descriptions and links of each website can be found here: https://medicine.yale.edu/lab/kaminski/research/atlas/. Methods: Each interactive data mining website is coded in the R language using the Shiny package and is hosted by Shinyapps.io. Percell expression data for each website is stored on a MySQL database hosted by Amazon Web Services (AWS). Time-associated website engagement statistics and gene query information is collected for each website using a combination of Google Analytics and a gene search table stored on our MySQL database. User exploration of available data is facilitated through several easy-touse visualization tools available on each website. Results: Website usage statistics since the publication of each website shows that 9,772 unique users from 56 countries and five continents have accessed at least one of the three websites. At the time of writing, 300,748 total queries have been made for 15,627 unique genes across the websites. The top five searched genes for the IPF Cell Atlas are CD14, ACE2, ACTA2, IL11 and MUC5B while for the COPD Cell Atlas they are FAM13A, MIRLET7BHG, HHIP, ISM1 and DDT. Finally, the top searched genes for the Lung Endothelial Cell Atlas are BMPR2, PECAM1, EDNRB, APLNR and PROX1. Of note, interaction with the IPF Cell Atlas increased dramatically at the start of the COVID-19 pandemic, with queries for the ACE2 gene, the putative binding receptor for the SARS-CoV-2 virus, increasing substantially at the pandemic's onset in the United States. Conclusions: Usage statistics, gene query information and feedback from users, both within academia and industry, have shown broad engagement with our websites by individuals across computational and non-computational backgrounds. We envision widespread adoption of web-based portals similar to ours will facilitate novel discoveries within these complex datasets and new scientific collaborations.
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INTRODUCTION: Infectious agents, including SARSCoV- 2, cause pulmonary endothelial cell (EC) dysfunction that leads to acute respiratory distress syndrome (ARDS). EC dysfunction involves increased leukocyte recruitment and cell permeability mediated by various junctional proteins, integrins, and adhesion molecules. The omega-3 fatty acid eicosapentaenoic acid (EPA) and its metabolites modulate inflammation and vascular function. These actions of EPA may contribute to reduced cardiovascular events as reported in outcome trials such as REDUCE-IT. Currently, EPA is being tested in patients at risk for or with COVID-19. This study tested the effects of EPA on protein expression in human pulmonary ECs following challenge by the cytokine IL-6 to simulate conditions encountered in advanced viral infections. METHODS: Human lung microvascular endothelial cells (HMVEC-L) were post-treated with vehicle or EPA (40 μM) in 2% FBS after a 2 hr challenge with IL-6 at 12 ng/ml for 24 h. Proteomic analysis used LC/MS to assess relative expression levels of EC proteins. Only significant (p< 0.05) changes in protein expression between treatment groups >1-fold were analyzed. Specific pathway analysis was carried out using gene set enrichment analysis (GSEA). RESULTS: HMVEC-L treated with EPA following challenge with IL-6 showed significant changes in over 400 proteins compared with IL-6 treatment alone. EPA specifically diminished eleven proteins in the “integrin cell surface interactions” pathway. These pathways proteins included integrins alpha-V, alpha-6, and beta-1, along with PECAM-1, junction adhesion molecule C (JAM3), fibronectin, and ICAM- 2. CONCLUSIONS: EPA reduced expression of pulmonary endothelial adhesion and permeability proteins following IL-6 treatment. The ability of EPA to inhibit EC dysfunction and inflammation may have benefits for patients with or at risk for ARDS due to viruses such as SARS-CoV-2 or sepsis.
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Introduction: Neuropilin-1 has been recently identified as a co-factor needed for the entry of SARSCoV-2 in host cells and has been linked to neurologic symptoms of COVID-19 (Science 2020). Emerging evidence indicates that exosomal microRNAs (miRNAs) are involved in a number of physiologic and pathologic processes. However, to our knowledge, exosomal miRNAs have not been hitherto investigated in COVID-19. Hypothesis: Since we have recently demonstrated that miR-24 targets the 3'UTR of the gene encoding for Neuropilin-1 and this miRNA is expressed in human brain endothelial cells, we hypothesized an association between plasma levels of CD31 extracellular vesicles (EVs) enriched in miR-24 and the risk of cerebrovascular manifestations in patients hospitalized for COVID-19. Methods and Results: We obtained plasma from >300 COVID-19 patients;as control COVID-19 negative populations, we obtained plasma from healthy donors and patients hospitalized for cerebrovascular disorders. CD31 EVs were isolated from plasma on hospital admission, and miR24 levels were quantified. When comparing patients with vs without cerebrovascular disorders, we found that plasma levels of CD31 EV miR-24 were significantly different between these populations. We did not find any significant difference among groups when assessing circulating free levels of miR-24. Using a multiple regression analysis, adjusting for age, hypertension, and diabetes, the association between EV miR-24 and cerebrovascular complications in COVID-19 patients was confirmed (P<0.05). Conclusions: This is the first study showing a significant association between EV non-coding RNAs and clinical outcome in COVID-19 patients. Our results are relevant for basic researchers, because we identified an unprecedented significant association between EV miR-24 and cerebrovascular disorders, which could be helpful to better understand the molecular mechanisms underlying the pathophysiology of cerebrovascular events in COVID-19, as well as for clinicians, inasmuch as this association may help healthcare professionals in identifying COVID-19 patients who are at high risk of developing cerebrovascular disease.
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TYPE: Case Report TOPIC: Chest Infections INTRODUCTION: Kaposi sarcoma (KS) is very commonly associated with Human Immunodeficiency Virus (HIV) infection. The clinical course of HIV associated KS could be indolent with muco-cutaneous or aggressive with visceral organ system involvement. It is extremely uncommon for the visceral involvement to occur in the absence of mucocutaneous manifestations. CASE PRESENTATION: A 45-year male with HIV, presented with fatigue, exertional dyspnea, cough. Vital signs showed low grade fever and hypoxia. On physical exam the pertinent positive finding was diffuse inspiratory crackles. The CT chest showed multiple irregular nodular infiltrates in the lungs. Blood and sputum cultures were collected, and the patient was started on empiric antibiotics and fluconazole. The viral load and the absolute CD4 count were 64,360 and 17, respectively. The transesophageal echocardiogram was negative for vegetations. SARS-COVID19, blood culture and three sputum acid fast bacilli were negative. The patient continued to worsen. The bronchoscopy showed a friable mass in the left lower trachea. The immunohistochemistry analysis of the lesions was positive for CD34, CD31, HHV-8, FLI-1 which was diagnostic of KS. The patient was started on Highly Active Antiretroviral Therapy (HAART) and was discharged on HAART with a scheduled follow up. DISCUSSION: The introduction of HAART has decreased the incidence of KS to 0.03 per 1000 patient years in the HAART era. 15.5 % of patients have pulmonary KS in the absence of mucocutaneous lesions. These rates of pulmonary KS in autopsy findings were noted in the pre-HAART era. CONCLUSIONS: To establish a diagnosis of pulmonary KS in the absence of the characteristic cutaneous lesions is challenging. DISCLOSURE: Nothing to declare. KEYWORD: Kaposi Sarcoma
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Severe SARS-CoV-2 infection is complicated by dysregulation of the blood coagulation system and high rates of thrombosis, but virus-intrinsic mechanisms underlying this phenomenon are poorly understood. Increased intracellular calcium concentrations promote externalization of phosphatidylserine (PS), the membrane anionic phospholipid required for assembly and activation of the tenase and prothrombinase complexes to drive blood coagulation. TMEM16F is a ubiquitous phospholipid scramblase that mediates externalization of PS in a calcium-dependent manner. As SARS-CoV-2 ORF3a encodes a presumed cation channel with the ability to transport calcium, we hypothesized that ORF3a expression by infected host cells perturbs the cellular calcium rheostat, driving TMEM16F-dependent externalization of PS and enhancing procoagulant activity. Using a doxycycline-inducible system, synchronized expression of ORF3a in A549 pulmonary epithelial cells resulted in a time-dependent augmentation of tissue factor (TF) procoagulant activity exceeding 9-fold by 48 hours (p < 0.0001), with no change in TF cell-surface expression. This enhancement was dependent upon PS as determined by inhibition with the PS-binding protein lactadherin. Over 2-fold enhancement of prothrombinase activity (p < 0.0001) was also observed by 48 hours. ORF3a increased intracellular calcium levels by 18-fold at 48 hours (p < 0.0001), as determined by the intracellular calcium indicator fluo-4. After 16 hours of ORF3a expression, more than 60% of cells had externalized PS (p < 0.001) without increased cell death, as quantified by flow cytometry following annexin V binding. Immunofluorescence microscopy staining for ORF3a, annexin V, and nuclei confirmed ORF3a expression within internal and cell surface membranes and increased PS externalization. PS externalization was insensitive to the pan-caspase inhibitor z-VAD-FMK, and there was no evidence of apoptotic activation as determined by caspase-3 cleavage. By contrast, ORF3a expression did not augment coagulation in cells deficient in the calcium-dependent phospholipid scramblase TMEM16F. Similarly, ORF3a-enhanced TF procoagulant activity (p < 0.01) and prothrombinase activity (p<0.05) was completely abrogated using TMEM16 inhibitors, including the uricosuric agent benzbromarone that has been registered for human use in over 20 countries. Live SARS-CoV-2 infection of A549-ACE2 cells increased cell surface factor Xa generation at MOI 0.1 (p < 0.01) but not MOI 0.01 or following heat inactivation of the virus, and RNA sequencing confirmed ORF3a induction without increased F3 expression. RNA sequencing of human SARS-CoV-2 infected lung autopsy and control tissue (n= 53) confirmed these findings in vivo. Immunofluorescence staining for ORF3a and KRT8/18 and CD31 in SARS-CoV-2 infected human lung autopsy specimens demonstrated ORF3a expression in pulmonary epithelium and endothelial cells, highlighting the potential pathologic relevance of this mechanism. Here we demonstrate that expression of the SARS-CoV-2 accessory protein ORF3a increases the intracellular calcium concentration and TMEM16F-dependent PS scrambling to augment procoagulant activity of the tenase and prothrombinase complexes. Our studies of human cells and tissues infected with SARS-CoV-2 support the pathologic relevance of this mechanism. We highlight the therapeutic potential to target the ORF3a-TMEM16F axis as with benzbromarone to mitigate dysregulation of coagulation and thrombosis during severe SARS-CoV-2 infection. Disclosures: Schwartz: Miromatrix Inc: Membership on an entity's Board of Directors or advisory committees;Alnylam Inc.: Consultancy, Speakers Bureau. Schulman: CSL Behring: Consultancy, Research Funding.
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BACKGROUND. COVID-19 is a prothrombotic disease, characterized by endotheliopathy, hypercoagulability, and thromboembolic complications. We hypothesized that the pathogenesis of thromboembolism associated with COVID-19 might differ from thromboembolism in patients without COVID-19. In this study, we sought to evaluate the proteomic signatures of plasma from patients with venous thromboembolism with and without COVID-19. METHODS. Between December 17, 2020 and February 25, 2021 blood was collected from 48 hospitalized patients. Of these 24 had a confirmed diagnosis of COVID-19 infection (COVID+) and radiologic confirmation of arterial or venous thromboembolism (TE+);17 had COVID-19 infection with absence of arterial thrombosis clinically and absence of venous thromboembolism on lower extremity Doppler ultrasound or chest CT angiography (COVID+/TE-), while 7 were arterial or venous thromboembolism in the absence of COVID-19 (COVID-/TE+). Blood was collected in sodium citrate tubes and centrifuged at 4000 rpm for 20 minutes, with resulting plasma supernatant used for protein profiling performed at Eve Technologies (Calgary, Alberta, Canada). Institutional Review Board approval was obtained for this study. Statistical analysis was performed using GraphPad Prism (v9.1, GraphPad Software, San Diego, CA) and R (v4, R Core Team). P values <0.05 were considered statistically significant. A heatmap was generated using Heatmapper (heatmapper.ca) to represent the concentrations of proteins. RESULTS. The median age was 63 years;overall 25 (52%) were men (13 [54%] among COVID+/TE+, 11 [65%] among COVID+/TE-, and 1 [14%] among COVID-/TE+). In COVID-19 patients who developed thromboembolic events, several proteins associated with inflammation, complement activation, and hemostasis were present at higher levels than in non-COVID-19 patients who developed thromboembolic events (Fig. 1). These included complement factors C2 and C5a, pentraxin-3 (PTX-3), lipocalin-2 (LCN2), resistin (RETN), platelet endothelial cell adhesion molecule-1 (Pecam1), serum amyloid A (SAA), and tissue factor (TF). The heatmap indicates relative protein levels detected in each subject (columns) for proteins (rows) that had statistically significant differences between groups (Fig. 2). Heatmap revealed relatively lower levels of all proteins in patients with thromboembolism without COVID-19 and relatively higher levels of proteins in patients with COVID-19, and especially in ICU patients with COVID-19 and thromboembolism. CONCLUSIONS. Thromboembolic complications in patients with COVID-19 are associated with increased levels of various proteins involved in complement activation and immunothrombotic cascades, compared to thrombotic events in the absence of COVID-19. Activation of the classical complement pathway as evidenced by a relative increase in complement factor C2 may lead to increased TF activation, reflecting more substantial endothelial damage in COVID-19 patients. Higher levels of Pecam1, SAA, LCN2, and RETN all point to increased endotheliopathy, inflammation, and tissue damage in COVID-19 compared to non-COVID-19 thrombosis. These findings may offer insights into novel therapeutic strategies to treat immunothrombotic complications of COVID-19. [Formula presented] Disclosures: No relevant conflicts of interest to declare.
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Background: COVID-19 is a disease caused by the SARS-CoV-2 virus that is often associated with pneumonia and acute respiratory distress syndrome (ARDS). Pathogenesis of COVID-19 is closely related to the host ' s response to the virus. Impaired regulation of immunity has been observed in patients with severe COVID-19 pneumonia. Mesenchymal stem cells (MSCs), having multipotency, ability to selfrenew, and ability to evade immune response may be useful in in the treatment of COVID-19 pneumonia. MSCs have an immunomodulatory effect on almost all types of immunocompetent cells: T-and B-lymphocytes, natural killer cells, monocytes and macrophages, dendritic cells, neutrophils. This study assesses the safety and tolerability of pooled allogeneic mesenchymal stem cells (poolMSC) in COVID 19 pneumonia. Method: The study included 5 patients with PCR confirmed COVID-19 pneumonia-4 men and 1 woman, average age 62.4 years. Pooled MSC (pMSC) was a mixture of 3 cultures of olfactory mucosa-derived MSCs (OM-MSCs) obtained from the mucous membrane of the middle nasal passage of healthy volunteers. MSCs were tested for viability (>95%), immunophenotype CD90 + CD105 + CD73 + CD31-CD45-HLA-DR-, and sterility. pMSC at a dosage of 1×10 6 cells per kg of body weight were suspended in 100 ml of saline and injected intravenously over 60 minutes. Results: All patients were carefully examined at baseline before pMSC infusion. Clinical examination was done on the day of infusion of pMSC with a skin test to pMSC was performed. In the absence of systemic and local allergic reactions pMSC were injected. Three patients received one pMSC infusion, and two patients received two pMSC infusions at an interval of 4 days. None of the patients had any adverse reactions to the pMSC skin test or infusion. Conclusion: Assessment of pMSC infusion demonstrated good tolerance and safety of intravenous use in patients with severe pneumonia caused by the SARS-CoV-2 and complicated by ARDS.