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Saline treated mice had marked perivascular mononuclear cell infiltrates after pristane induction DAH (A). Serp-1 treatment produced a non significant reduction in perivascular inflammatory cell counts (B). Serp-1m5 treatment significantly reduced perivascular inflammatory cell counts when compared to the saline treated controls (C). Perivascular mononuclear cell counts ± SEM are illustrated in panel (D). *p < 0.05.
Source publication
Diffuse alveolar hemorrhage (DAH) is one of the most serious clinical complications of systemic lupus erythematosus (SLE). The prevalence of DAH is reported to range from 1 to 5%, but while DAH is considered a rare complication there is a reported 50-80% mortality. There is at present no proven effective treatment for DAH and the therapeutics that...
Citations
... Clinical trials have reported that tissue plasminogen activator (TPA) treatment could improve respiratory status in patients with severe COVID-19 (28). Additionally, the inhibition of fibrinolytic protease has been shown to reduce the imbalance between thrombosis and thrombotic cascade, thereby alleviating inflammation in the DAH murine model (29,30). Several studies have also suggested that Hp is an anti-inflammatory acute phase protein, with its serum level associated with the transmission and severity of COVID-19 infection (31,32). ...
Background
Diffuse alveolar hemorrhage (DAH) is a catastrophic clinical syndrome and one of the manifestations of pulmonary involvement in systemic lupus erythematosus (SLE), which is characterized by hemoptysis, diffuse pulmonary infiltrates, and respiratory failure. However, the treatment options for DAH remain limited, and DAH-related studies are needed to explore more effective therapeutic directions for better disease management and improved prognosis.
Methods
This study utilized the pristane-induced DAH murine model to mimic the pathological process of DAH in patients with SLE. Proteomic analysis was conducted to detect differentially expressed proteins (DEPs) in the plasma of surviving and non-surviving mice, followed by an analysis of biological functions and pathways. The most significant DEP was then confirmed in the plasma of SLE patients with or without DAH and DAH murine model with or without fatal outcomes. Finally, the therapeutic value of haptoglobin (Hp) replacement was validated in a DAH murine model through lung histopathology, RT-qPCR, and survival analysis.
Results
This study identified 178 DEPs, with 118 upregulated and 60 downregulated DEPs in the non-survival group. Within a set of notable Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, complement and coagulation cascades emerged as the most prominent pathway associated with the process of DAH. Later, the most significant DEP, haptoglobin (Hp), was confirmed to exhibit a significant decrease in the plasma of individuals with SLE-DAH and DAH murine model with poor outcomes by the ELISA test. Finally, compared with the control group, the severity of DAH in the Hp treatment group was alleviated significantly, as manifested by the decreased levels of pro-inflammatory cytokines (IL-6 and TNF-α), increased levels of anti-inflammatory cytokines (IL-10 and TGF-β), and decreased mortality.
Conclusion
A reduction in plasma Hp levels was observed in SLE-DAH, and the replacement therapy with Hp could alleviate pulmonary hemorrhage and reduce mortality in DAH mice. This study identified Hp as a potential biomarker for its clinical diagnosis and a direction for treatment.
... Serp-1, a serpin encoded in the myxoma virus (MyxV) genome, has been tested as a therapeutic target for several inflammatory disorders as well as viral infections with notable success, as outlined in the review by Varkoly et al. [171]. By inhibiting the urokinase-type plasminogen activator receptor, complement receptors, and some of the thrombolytic enzymes (such as the previously discussed plasmin), it can prevent the overactivation of the immune response [172][173][174]. The success of using a viral serpin, which was originally made to support a viral infection, to then treat disease caused by viral infections is highly promising and supports the notion that the viral use of host proteases exists in a balance which we can seek to disrupt. ...
Viral tropism is most commonly linked to receptor use, but host cell protease use can be a notable factor in susceptibility to infection. Here we review the use of host cell proteases by human viruses, focusing on those with primarily respiratory tropism, particularly SARS-CoV-2. We first describe the various classes of proteases present in the respiratory tract, as well as elsewhere in the body, and incorporate the targeting of these proteases as therapeutic drugs for use in humans. Host cell proteases are also linked to the systemic spread of viruses and play important roles outside of the respiratory tract; therefore, we address how proteases affect viruses across the spectrum of infections that can occur in humans, intending to understand the extrapulmonary spread of SARS-CoV-2.
... Myxomavirus encodes and expresses two distinct serpins, Serp-1, which is secreted by an infected cell, and Serp-2, which operates intracellularly, albeit displaying extracellular anti-inflammatory activities. Serp-1 binds and inhibits extracellular thrombolytic and thrombotic proteases as well as complement proteases [17][18][19]56,57], while Serp-2 inhibits intracellular and cell surface apoptosis pathway proteases, granzyme B, a serine protease, and caspases 1 and 8, which are cysteine proteases [23,29,40,41]. CrmA and Spi2 are intracellular serpins derived from cowpox and vaccinia virus and also target the apoptotic pathways. ...
... Serp-1 regulates the excess activation of immune responses through the inhibition of coagulation and complement proteases. Serp-1 binds thrombolytic and thrombotic proteases (tPA, uPA, plasmin, fXa, and thrombin (in the presence of heparin, as well as complement proteases, as demonstrated by immunoprecipitation and mass spectrometry [17,57]. Serp-1, as in the case for the mammalian serpins PAI-1, alpha 2 anti-plasmin (A2AP), protease nexin-1 (PN-1), and A1AT, binds and inhibits more than one serine protease. ...
... Diffuse alveolar hemorrhage (DAH) is a rare and highly lethal complication in systemic lupus erythematosus (SLE), occurring in 1-5% of cases but with a mortality up to 50-80%. Current treatments are limited, although some newer treatment approaches such as infusion of the clotting factor VII are under investigation [17,44]. WT Serp-1 and a PEGylated variant, PEGSerp-1, that has an increased half-life from 20 min to 8 h, were assessed for treatment in a mouse model of pristane-induced DAH. ...
Serine protease inhibitors, SERPINS, are a highly conserved family of proteins that regulate serine proteases in the central coagulation and immune pathways, representing 2–10% of circulating proteins in the blood. Serine proteases form cascades of sequentially activated enzymes that direct thrombosis (clot formation) and thrombolysis (clot dissolution), complement activation in immune responses and also programmed cell death (apoptosis). Virus-derived serpins have co-evolved with mammalian proteases and serpins, developing into highly effective inhibitors of mammalian proteolytic pathways. Through interacting with extracellular and intracellular serine and cysteine proteases, viral serpins provide a new class of highly active virus-derived coagulation-, immune-, and apoptosis-modulating drug candidates. Viral serpins have unique characteristics: (1) function at micrograms per kilogram doses; (2) selectivity in targeting sites of protease activation; (3) minimal side effects at active concentrations; and (4) the demonstrated capacity to be modified, or fine-tuned, for altered protease targeting. To date, the virus-derived serpin class of biologics has proven effective in a wide range of animal models and in one clinical trial in patients with unstable coronary disease. Here, we outline the known viral serpins and review prior studies with viral serpins, considering their potential for application as new sources for immune-, coagulation-, and apoptosis-modulating therapeutics.
... At the time of necropsy the whole lung was quickly removed from the chest cavity and immediately photographed. This photograph was used to assess lung hemorrhaging via gross analyses (e.g., coagulation of blood at the surface of the lung or discoloration) as previously described [48,49]. Next, the right lobe of the lung was excised from the whole lung and weighed. ...
New bronchopulmonary dysplasia (BPD) is a neonatal disease that is theorized to begin in utero and manifests as reduced alveolarization due to inflammation of the lung. Risk factors for new BPD in human infants include intrauterine growth restriction (IUGR), premature birth (PTB) and formula feeding. Using a mouse model, our group recently reported that a paternal history of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure increased his offspring’s risk of IUGR, PTB, and new BPD. Additionally, formula supplementation of these neonates worsened the severity of pulmonary disease. In a separate study, we reported that a paternal preconception fish oil diet prevented TCDD-driven IUGR and PTB. Not surprisingly, eliminating these two major risk factors for new BPD also significantly reduced development of neonatal lung disease. However, this prior study did not examine the potential mechanism for fish oil’s protective effect. Herein, we sought to determine whether a paternal preconception fish oil diet attenuated toxicant-associated lung inflammation, which is an important contributor to the pathogenesis of new BPD. Compared to offspring of standard diet TCDD-exposed males, offspring of TCDD-exposed males provided a fish oil diet prior to conception exhibited a significant reduction in pulmonary expression of multiple pro-inflammatory mediators (Tlr4, Cxcr2, Il-1 alpha). Additionally, neonatal lungs of pups born to fish oil treated fathers exhibited minimal hemorrhaging or edema. Currently, prevention of BPD is largely focused on maternal strategies to improve health (e.g., smoking cessation) or reduce risk of PTB (e.g., progesterone supplementation). Our studies in mice support a role for also targeting paternal factors to improve pregnancy outcomes and child health.
... uPAR (CD87) is a glycosylphosphatidylinositol (GPI)-linked surface protein that sits in a large lipid raft of proteins that interact with integrins, chemokine receptors, vitronectin, growth factors, low density lipoprotein receptor-related protein (LRP) and complement receptors on the cell surface, altering cell activation and motility (48). Serp-1 also binds and inhibits several complement proteases (49). Bolus systemic treatment with clinical grade Serp-1 has proven safe and effective in a Phase IIA randomized dose escalating clinical trial, performed at 7 sites in the US and Canada, in unstable coronary syndrome patients with stent implants (50). ...
... A modified PEGylated serpin, PEGSerp-1 has been recently developed with improved halflife and activity (49). This modified Serp-1 still effectively binds uPA, tPA and thrombin and a series of complement proteases, specifically C1(q,r and s), factor B, C3 and C4 proteases as assessed by mass spectrometry. ...
... PEGSerp-1 represents a new class of immune modulating virus-derived biologic with extensive proven efficacy in a wide spectrum of systemic inflammatory diseases, including gamma herpesviral vasculitis (43) and lung infection, pristane-induced diffuse alveolar hemorrhage (DAH)(49), numerous animal models of vascular injury and allograft transplants (43). In both the virus infection and DAH models, serpin treatment altered expression levels of numerous coagulation and complement pathway proteases and serpins (43,49). ...
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. Ser ine p rotease in hibitors (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. Ser ine p rotease in hibitors (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.
... Treatment with purified native Serp-1 has demonstrated both acute and long-term efficacy in modulating inflammation in a wide range of inflammatory disorders and injuries, including atherosclerosis, transplant, wound healing, and spinal cord injury [39][40][41][42]. More recently, a modified Serp-1 protein, PEGSerp-1, with a longer halflife (~8 h), was shown to reduce inflammation and fibrosis in healing corneal wounds, and reduced macrophage invasion of alveoli in a mouse model of diffuse alveolar hemorrhage [43][44][45]. Based on these previous studies, we examined whether the pegylated version of the viral Serp-1 protein, PEGSerp-1, would ameliorate the chronic inflammatory pathology of DMD. ...
... Serp-1 was endotoxin-free, as detected by limulus amebocyte lysate (LAL) assay. Serp-1 was incubated with mPEG-NHS (5 K) (Nanocs Inc., #PG1-SC-5k-1, New York, NY, USA) in PBS (pH 7.8) at 4 • C overnight to modify the protein according to standard PEGylation protocols [43]. PEGylated-Serp-1 was purified by FPLC using an ÄKTA pure protein purification system with Superdex-200 [43]. ...
... Serp-1 was incubated with mPEG-NHS (5 K) (Nanocs Inc., #PG1-SC-5k-1, New York, NY, USA) in PBS (pH 7.8) at 4 • C overnight to modify the protein according to standard PEGylation protocols [43]. PEGylated-Serp-1 was purified by FPLC using an ÄKTA pure protein purification system with Superdex-200 [43]. ...
Duchenne muscular dystrophy is an X-linked disease afflicting 1 in 3500 males that is characterized by muscle weakness and wasting during early childhood, and loss of ambulation and death by early adulthood. Chronic inflammation due to myofiber instability leads to fibrosis, which is a primary cause of loss of ambulation and cardiorespiratory insufficiency. Current standard of care focuses on reducing inflammation with corticosteroids, which have serious adverse effects. It is imperative to identify alternate immunosuppressants as treatments to reduce fibrosis and mortality. Serp-1, a Myxoma virus-derived 55 kDa secreted glycoprotein, has proven efficacy in a range of animal models of acute inflammation, and its safety and efficacy has been shown in a clinical trial. In this initial study, we examined whether pegylated Serp-1 (PEGSerp-1) treatment would ameliorate chronic inflammation in a mouse model for Duchenne muscular dystrophy. Our data revealed a significant reduction in diaphragm fibrosis and increased myofiber diameter, and significantly decreased pro-inflammatory M1 macrophage infiltration. The M2a macrophage and overall T cell populations showed no change. These data demonstrate that treatment with this new class of poxvirus-derived immune-modulating serpin has potential as a therapeutic approach designed to ameliorate DMD pathology and facilitate muscle regeneration.
... A PEGylated version of the Myxomavirus derived SERPIN Serp-1 has also been developed demonstrating improved efficacy in a mouse model of diffuse alveolar hemorrhage (259). Serp-1 is a broad acting SERPIN with anti-inflammatory and antifibrinolytic activities (260). ...
Appropriate activation of coagulation requires a balance between procoagulant and anticoagulant proteins in blood. Loss in this balance leads to hemorrhage and thrombosis. A number of endogenous anticoagulant proteins, such as antithrombin and heparin cofactor II, are members of the serine protease inhibitor (SERPIN) family. These SERPIN anticoagulants function by forming irreversible inhibitory complexes with target coagulation proteases. Mutations in SERPIN family members, such as antithrombin, can cause hereditary thrombophilias. In addition, low plasma levels of SERPINs have been associated with an increased risk of thrombosis. Here, we review the biological activities of the different anticoagulant SERPINs. We further consider the clinical consequences of SERPIN deficiencies and insights gained from preclinical disease models. Finally, we discuss the potential utility of engineered SERPINs as novel therapies for the treatment of thrombotic pathologies.
The urokinase-type plasminogen activator receptor (uPAR) is a unique protease binding receptor, now recognized as a key regulator of inflammation. Initially, uPA/uPAR was considered thrombolytic (clot-dissolving); however, recent studies have demonstrated its predominant immunomodulatory functions in inflammation and cancer. The uPA/uPAR complex has a multifaceted central role in both normal physiological and also pathological responses. uPAR is expressed as a glycophosphatidylinositol (GPI)-linked receptor interacting with vitronectin, integrins, G protein-coupled receptors, and growth factor receptors within a large lipid raft. Through protein-to-protein interactions, cell surface uPAR modulates intracellular signaling, altering cellular adhesion and migration. The uPA/uPAR also modifies extracellular activity, activating plasminogen to form plasmin, which breaks down fibrin, dissolving clots and activating matrix metalloproteinases that lyse connective tissue, allowing immune and cancer cell invasion and releasing growth factors. uPAR is now recognized as a biomarker for inflammatory diseases and cancer; uPAR and soluble uPAR fragments (suPAR) are increased in viral sepsis (COVID-19), inflammatory bowel disease, and metastasis. Here, we provide a comprehensive overview of the structure, function, and current studies examining uPAR and suPAR as diagnostic markers and therapeutic targets. Understanding uPAR is central to developing diagnostic markers and the ongoing development of antibody, small-molecule, nanogel, and virus-derived immune-modulating treatments that target uPAR.
SARS-CoV-2 acute respiratory distress syndrome (ARDS) induces uncontrolled lung inflammation and coagulopathy with high mortality. Anti-viral drugs and monoclonal antibodies reduce early COVID-19 severity, but treatments for late-stage immuno-thrombotic syndromes and long COVID are limited. Serine protease inhibitors (SERPINS) regulate activated proteases. The myxoma virus-derived Serp-1 protein is a secreted immunomodulatory serpin that targets activated thrombotic, thrombolytic, and complement proteases as a self-defense strategy to combat clearance. Serp-1 is effective in multiple animal models of inflammatory lung disease and vasculitis. Here, we describe systemic treatment with purified PEGylated Serp-1 as a therapy for immuno-coagulopathic complications during ARDS. Treatment with PEGSerp-1 in two mouse-adapted SARS-CoV-2 models in C57Bl/6 and BALB/c mice reduced lung and heart inflammation, with improved outcomes. PEGSerp-1 significantly reduced M1 macrophages in the lung and heart by modifying urokinase-type plasminogen activator receptor (uPAR), thrombotic proteases, and complement membrane attack complex (MAC). Sequential changes in gene expression for uPAR and serpins (complement and plasminogen inhibitors) were observed. PEGSerp-1 is a highly effective immune-modulator with therapeutic potential for severe viral ARDS, immuno-coagulopathic responses, and Long COVID.
Introduction: Diffuse alveolar hemorrhage (DAH) is a serious complication caused by systemic lupus erythematosus (SLE). Tissue damage and changes in immune response are all associated with excessive free radical production. Therefore, removing excess reactive oxygen species are considered a feasible scheme for diffuse alveolar hemorrhage treatment. Cyclophosphamide is often used as the main therapeutic drug in clinics. However, CTX carries a high risk of dose-increasing toxicity, treatment intolerance, and high recurrence rate. The combination of therapeutic drugs and functional nanocarriers may provide an effective solution. PDA is rich in phenolic groups, which can remove the reactive oxygen species generated in inflammatory reactions, and can serve as excellent free radical scavengers.
Methods: We developed a hollow polydopamine (HPDA) nanocarrier loaded with CTX by ionization to prepare the novel nanoplatform, CTX@HPDA, for DAH treatment. The monodisperse silica nanoparticles were acquired by reference to the typical Stober method. PDA was coated on the surface of SiO2 by oxidation self-polymerization method to obtain SiO2@PDA NPs. Then, HPDA NPs were obtained by HF etching. Then HPDA was loaded with CTX by ionization to prepare CTX@HPDA. Then we tested the photothermal effect, animal model therapeutics effect, and biosafety of CTX@HPDA.
Results: Material tests showed that the CTX@ HPDA nanoplatform had a uniform diameter and could release CTX in acidic environments. The vitro experiments demonstrated that CTX@HPDA has good photothermal conversion ability and photothermal stability. Animal experiments demonstrated that the CTX@HPDA nanoplatform had good biocompatibility. The nanoplatform can dissociate in acidic SLE environment and trigger CTX release through photothermal conversion. Combining HPDA, which scavenges oxygen free radicals, and CTX, which has immunosuppressive effect, can treat pulmonary hemorrhage in SLE. Micro-CT can be used to continuously analyze DAH severity and lung changes in mice after treatment. The pulmonary exudation in the various treatment groups improved to varying degrees.
Discussion: In this study, we report a photothermal/PH-triggered nanocarrier (CTX@HPDA) for the precise treatment of SLE-DAH. CTX@HPDA is a simple and efficient nanocarrier system for DAH therapy. This work provides valuable insights into SLE treatment.
