Severe acute respiratory distress syndrome (ARDS) during SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2) infection, manifests as uncontrolled lung inflammation and systemic thrombosis with high mortality. Anti-viral drugs and monoclonal antibodies can reduce COVID-19 severity if administered in the early viremic phase, but treatments for later stage immuno-thrombotic syndrome and long COVID are limited. Serine protease inhibitors (SERPINS) regulate activated proteases during thrombotic, thrombolytic and immune responses. The myxoma poxvirus-derived Serp-1 protein is a secreted immunomodulatory serpin that targets activated coagulation and complement protease pathways as part of a self-defense strategy to combat viral clearance by the innate immune system. When purified and utilized as an anti-immune therapeutic, Serp-1 is effective as an anti-inflammatory drug in multiple animal models of inflammatory lung disease and vasculitis. Here, we describe systemic treatment with purified PEGylated Serp-1 (PEGSerp-1) as a therapy for immuno-thrombotic complications during ARDS. Treatment with PEGSerp-1 in two distinct mouse-adapted SARS-CoV-2 models in C57Bl/6 and BALB/c mice reduced lung and heart inflammation, with improved clinical outcomes. PEGSerp-1 significantly reduced M1 macrophage invasion in the lung and heart by modifying urokinase-type plasminogen activator receptor (uPAR) and complement membrane attack complex (MAC). Sequential changes in urokinase-type plasminogen activator receptor (uPAR) and serpin gene expression were observed in lung and heart with PEGSerp-1 treatment. PEGSerp-1 is a highly effective immune-modulator with therapeutic potential for treatment of severe viral ARDS with additional potential to reduce late SARS-CoV-2 complications related to immune-thrombotic events that persist during long COVID. Significance: Severe acute respiratory distress syndrome (ARDS) in SARS-CoV-2 infection manifests as uncontrolled tissue inflammation and systemic thrombosis with high mortality. Anti-viral drugs and monoclonal antibodies reduce COVID-19 severity if administered early, but treatments for later stage immuno-thrombosis are limited. Serine protease inhibitors (SERPINS) regulate thrombotic, thrombolytic and complement pathways. We investigate here systemic treatment with purified poxvirus-derived PEGSerp-1 as a therapeutic for immuno-thrombotic complications in viral ARDS. PEGSerp-1 treatment in two mouse-adapted SARS-CoV-2 models (C57Bl/6 and BALB/c) significantly reduced lung and heart inflammation and improved clinical outcomes, with sequential changes in thrombolytic (uPAR) and complement expression. PEGSerp-1 is a highly effective immune-modulator with therapeutic potential for immune-thrombotic complications in severe viral ARDS and has potential benefit for long COVID.

BackgroundViral infections are pervasive and leading causes of myocarditis. Immune-suppression after chemotherapy increases opportunistic infections, but the incidence of virus-induced myocarditis is unknown.ObjectiveAn unbiased, blinded screening for RNA viruses was performed after chemotherapy with correlation to cardiac function.MethodsHigh-throughput sequencing of RNA isolated from blood samples was analyzed following chemotherapy for hematological malignancies (N = 28) and compared with left ventricular ejection fraction (LVEF).ResultsOn initial rigorous analysis, low levels of influenza orthomyxovirus and avian paramyxovirus sequences were detectable, but without significant correlation to LVEF (r = 0.208). A secondary broad data mining analysis for virus sequences, without filtering human sequences, detected significant correlations for paramyxovirus with LVEF after chemotherapy (r = 0.592, P < 0.0096). Correlations were similar for LVEF pre- and post- chemotherapy for orthomyxovirus (R = 0.483, P < 0.0421). Retrovirus detection also correlated with LVEF post (r = 0.453, p < 0.0591), but not pre-chemotherapy, but is suspect due to potential host contamination. Detectable phage and anellovirus had no correlation. Combined sequence reads (all viruses) demonstrated significant correlation (r = 0.621, P < 0.0078). Reduced LVEF was not associated with chemotherapy (P = NS).ConclusionsThis is the first report of RNA virus screening in circulating blood and association with changes in cardiac function among patients post chemotherapy, using unbiased, blinded, high-throughput sequencing. Influenza orthomyxovirus, avian paramyxovirus and retrovirus sequences were detectable in patients with reduced LVEF. Further analysis for RNA virus infections in patients with cardiomyopathy after chemotherapy is warranted.

Immune cell invasion after the transplantation of solid organs is directed by chemokines binding to glycosaminoglycans (GAGs), creating gradients that guide immune cell infiltration. Renal transplant is the preferred treatment for end stage renal failure, but organ supply is limited and allografts are often injured during transport, surgery or by cytokine storm in deceased donors. While treatment for adaptive immune responses during rejection is excellent, treatment for early inflammatory damage is less effective. Viruses have developed highly active chemokine inhibitors as a means to evade host responses. The myxoma virus-derived M-T7 protein blocks chemokine: GAG binding. We have investigated M-T7 and also antisense (ASO) as pre-treatments to modify chemokine: GAG interactions to reduce donor organ damage. Immediate pre-treatment of donor kidneys with M-T7 to block chemokine: GAG binding significantly reduced the inflammation and scarring in subcapsular and subcutaneous allografts. Antisense to N-deacetylase N-sulfotransferase1 (ASONdst1) that modifies heparan sulfate, was less effective with immediate pre-treatment, but reduced scarring and C4d staining with donor pre-treatment for 7 days before transplantation. Grafts with conditional Ndst1 deficiency had reduced inflammation. Local inhibition of chemokine: GAG binding in donor organs immediately prior to transplant provides a new approach to reduce transplant damage and graft loss.

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Introduction: Acute respiratory distress syndromes with vascular inflammation and alveolar hemorrhage have high mortality and limited treatment. Autoimmune disease and severe viral infection cause vascular inflammation and hemorrhage. Serine protease coagulation pathways increase inflammatory cell activation and damage. Viruses have evolved highly effective immune modulating ser ine p roteinase in hibitors, serpins . Myxomavirus Serp-1 improves survival and reduces inflammation, vasculitis and lung hemorrhage in MHV68 gamma herpes infections (P < 0.01). Serp-1 also reduces Lupus alveolar hemorrhage (DAH) and proved safe and effective in a randomized, blinded, dose escalating trial in patients with coronary stent implant. Hypothesis: We hypothesize that treatment with PEGylated Serp-1 (PEGSerp-1) will reduce hemorrhage and inflammatory vasculitis in autoimmune and infectious lung disease. Methods: Pristane induced DAH and SARS-CoV-2 virus infections were treated with PEGSerp-1 in mouse models. Results: Serp-1 and PEGSerp-1 given daily IP for 14 days significantly reduced pristane induced DAH (N = 30 C57Bl/6 mice; P < 0.05) at 14 days follow up. PEGSerp-1 also reduced lung hemorrhage given for 7days treatment (N = 6 mice; P <0.01) or when given 7 days after pristane induction of DAH (N = 6 mice; P < 0.01). Macrophage invasion (P < 0.01), Prussian blue staining for hemosiderosis, C5b-9 complex deposition and soluble uPAR (suPAR) were significantly reduced with PEGSerp-1 treatment. PEGSerp-1 given daily after SARS-CoV-2 infection (48hrs, BALB/c mice, N = 16) also significantly reduced lung inflammation; decreased F4/80+ and iNOS+ macrophage staining (P < 0.02). Virus titer was also reduced in TMPRS2+ Vero cells (10μg/mL), and in SARS infected lungs. PEG Serp-1 homes to areas of pristane lung damage, but not normal lungs, indicating targeting of protease activation. No adverse effects were detected. Conclusion: Treatment for vascular inflammation and hemorrhage in severe autoimmune and virus induced respiratory distress syndromes is very limited. Targeting thrombolytic and inflammatory serine protease uPA/ uPAR complex activation provides a new therapeutic approach to severe respiratory distress in autoimmune disease and viral infection.