Project description:Life-threatening thrombotic events and neurological symptoms are prevalent in COVID-19 and are persistent in patients with long COVID experiencing post-acute sequelae of SARS-CoV-2 infection1,2,3,4. Despite the clinical evidence1,5,6,7, the underlying mechanisms of coagulopathy in COVID-19 and its consequences in inflammation and neuropathology remain poorly understood and treatment options are insufficient. Fibrinogen, the central structural component of blood clots, is abundantly deposited in the lungs and brains of patients with COVID-19, correlates with disease severity and is a predictive biomarker for post-COVID-19 cognitive deficits1,5,8,9,10. Here we show that fibrin binds to the SARS-CoV-2 spike protein, forming proinflammatory blood clots that drive systemic thromboinflammation and neuropathology in COVID-19. Fibrin, acting through its inflammatory domain, is required for oxidative stress and macrophage activation in the lungs, whereas it suppresses natural killer cells, after SARS-CoV-2 infection. Fibrin promotes neuroinflammation and neuronal loss after infection, as well as innate immune activation in the brain and lungs independently of active infection. A monoclonal antibody targeting the inflammatory fibrin domain provides protection from microglial activation and neuronal injury, as well as from thromboinflammation in the lung after infection. Thus, fibrin drives inflammation and neuropathology in SARS-CoV-2 infection, and fibrin-targeting immunotherapy may represent a therapeutic intervention for patients with acute COVID-19 and long COVID.
Project description:Life-threatening thrombotic events and neurological symptoms are prevalent in COVID-19 and are persistent in patients with long COVID experiencing post-acute sequelae of SARS-CoV-2 infection1,2,3,4. Despite the clinical evidence1,5,6,7, the underlying mechanisms of coagulopathy in COVID-19 and its consequences in inflammation and neuropathology remain poorly understood and treatment options are insufficient. Fibrinogen, the central structural component of blood clots, is abundantly deposited in the lungs and brains of patients with COVID-19, correlates with disease severity and is a predictive biomarker for post-COVID-19 cognitive deficits1,5,8,9,10. Here we show that fibrin binds to the SARS-CoV-2 spike protein, forming proinflammatory blood clots that drive systemic thromboinflammation and neuropathology in COVID-19. Fibrin, acting through its inflammatory domain, is required for oxidative stress and macrophage activation in the lungs, whereas it suppresses natural killer cells, after SARS-CoV-2 infection. Fibrin promotes neuroinflammation and neuronal loss after infection, as well as innate immune activation in the brain and lungs independently of active infection. A monoclonal antibody targeting the inflammatory fibrin domain provides protection from microglial activation and neuronal injury, as well as from thromboinflammation in the lung after infection. Thus, fibrin drives inflammation and neuropathology in SARS-CoV-2 infection, and fibrin-targeting immunotherapy may represent a therapeutic intervention for patients with acute COVID-19 and long COVID.
Project description:The presence and amount of the proteins within a plasma clot may influence clot properties, like susceptibility to fibrinolysis, however, the plasma clot proteome has not yet been extensively described. The aim of the study was to investigate the protein composition of clots prepared ex vivo from plasma of the peripheral blood of four patients with acute myocardial infarction (AMI) in two time points: in the acute ischemic phase and two months later during the standard therapy. Proteomic analysis revealed a total number of 62 proteins identified in all 8 samples grouping into several distinct functional clusters (e.g. cholesterol transporter activity, immunoglobulin binding and peptidase regulatory activity). The protein signatures of clots differed significantly depending on time after ACS, showing 30% greater variability in protein composition of the clots prepared in the plasma two months after the onset of AMI as compared to the clots generated at the time of admission to the hospital. Several proteins that could be involved in clot formation and resolution showed an interesting pattern of changes over time. For example α2-antiplasmin, which was robustly present in clots of all patients in acute phase of AMI, was detectable in lower abundance in only 2 clots prepared in plasma taken 8-12 weeks after AMI, whereas serotransferrin can be detected only in the clots prepared from plasma taken later during the therapy. In conclusion, we provided the first qualitative analysis of proteomes of fibrin clots generated ex vivo in plasma taken from patients with AMI showing differences in protein composition between clots generated in the acute ischemic phase and those prepared two months later. It might be hypothesized that differences involving several proteins of potential influence on within-clot fibrinolysis and clot stability may partially explain time-dependent changes in the clots structure and firmness in patients with AMI.
Project description:Traumatic brain injury (TBI) causes significant blood-brain barrier (BBB) breakdown, resulting in the extravasation of blood proteins into the brain. The impact of blood proteins, especially fibrinogen, on inflammation and neurodegeneration post-TBI is not fully understood, highlighting a critical gap in our comprehension of TBI pathology and its connection to innate immune activation. We combined vascular casting with 3D imaging of solvent-cleared organs (uDISCO) to study the spatial distribution of the blood coagulation protein fibrinogen in large, intact brain volumes and assessed the temporal regulation of the fibrin(ogen) deposition by immunohistochemistry in a murine model of TBI. Fibrin(ogen) deposition and innate immune cell markers were co-localized by immunohistochemistry in mouse and human brains after TBI. We assessed the role of fibrinogen in TBI using unbiased transcriptomics, flow cytometry and immunohistochemistry for innate immune and neuronal markers in Fggγ390–396A knock-in mice, which express a mutant fibrinogen that retains normal clotting function, but lacks the γ390–396 binding motif to CD11b/CD18 integrin receptor. We show that cerebral fibrinogen deposits were associated with activated innate immune cells in both human and murine TBI. Genetic elimination of fibrin-CD11b interaction reduced peripheral monocyte recruitment and the activation of inflammatory and reactive oxygen species (ROS) gene pathways in microglia and macrophages after TBI. Blockade of the fibrin-CD11b interaction was also protective from oxidative stress damage and cortical loss after TBI. These data suggest that fibrinogen is a regulator of innate immune activation and neurodegeneration in TBI. Abrogating post-injury neuroinflammation by selective blockade of fibrin’s inflammatory functions may have implications for long-term neurologic recovery following brain trauma.
Project description:Antiphospholipid syndrome (APS) is associated with arterial and venous thrombosis. The unfavorable fibrin clot phenotype, including formation of dense and poorly lysable clots, has been reported both in thrombotic APS and venous thromboembolism (VTE). The presence and amount of different proteins within a plasma clot, not only associated with the coagulation system, may influence clot properties. To our knowledge, there is a lack of data on plasma fibrin-clot bound proteins in patients with thrombotic APS or VTE. The aim of our study was to perform a quantitative proteomic analysis of fibrin clots prepared from citrated plasma from subjects with thrombotic APS and prior VTE, along with fibrin clot permeability (Ks) and clot lysis time (CLT) assessed ex vivo. We investigated 23 consecutive patients with APS, 18 with a history of first-ever VTE, and 20 age and sex matched healthy subjects. A multiple enzyme digestion filter aided sample preparation and a multienzyme digestion (MED) FASP method combined with LC-MS/MS analysis performed on a Proxeon Easy-nLC System coupled to the Q Exactive HF mass spectrometer were used. The proteomic analysis revealed that clot composition regarding 117 proteins in APS patients and 48 proteins in VTE patients was changed as compared to healthy controls, while 72 clot-bounded proteins differed between APS and VTE subjects. In healthy controls, Ks was associated with fibrinogen alpha and gamma chains (r=0.46 and r=0.46, both p<0.05, respectively) or apolipoprotein B-100 (r=-0.53, p<0.05), while CLT correlated with annexin A2 (r=-0.58, p<0.05), apolipoportein(a) (r=0.47, p<0.05), or platelet glycoprotein 4 (r=0.59, p<0.05). In VTE patients correlations of Ks with complement C1q and histone H2B, as factors closely linked with thrombosis, were observed (r=-0.52 and r=-0.47, both p<0.05, respectively). In patients with thrombotic APS all above-mentioned associations were not found. This study is the first to show that different proteins are able to influence the clot formation, structure, and properties. Since, prothrombotic conditions abolished associations observed in healthy subjects fibrin clots, differences in protein clot components might explain the links between prothrombotic fibrin clot phenotype and thromboembolic events.
Project description:Previously, we established an antibody, termed 102-10, which recognizes insoluble fibrin exclusively, unlike the previously established anti-insoluble fibrin antibodies that also cross-reacted with fibrinogen. We established that the epitope of this antibody is on the β chain that lines an indented structure that becomes exposed only when insoluble fibrin is formed. The amino acid sequence of the epitope is completely conserved from mouse to humans. This study attempted to determine the most suitable insoluble fibrin clone for future diagnostic and therapeutic development. Binding kinetics and properties of antibodies were evaluated by the surface plasmon resonance analysis (SPR) and ELISA among 1101, 99, 443, and 102-10. Immunohistochemical staining for mouse and human pancreatic cancer tissues were also performed. For frozen sections, visually appropriate staining results were observed at an antibody concentration of 1-10 μg/ml, while for paraffin sections, 10 μg/ml was required. From immunohistochemistry and ELISA analyses, clone 99 and clone 1101 showed almost no nonspecific binding in normal pancreatic tissues. Hybridoma production for 1101 yielded more antibodies than that of 99 and demonstrated good long-term stability. It was, therefore, concluded that clone 1101 would be useful for future clinical development as well as basic research.
Project description:Cancer-induced blood coagulation in human tumour generates insoluble fibrin (IF)-rich cancer stroma in which uneven monoclonal antibody (mAb) distribution reduce the potential effectiveness of mAb-mediated treatments. Previously, we developed a mAb that reacts only with IF and not with fibrinogen (FNG) or the fibrin degradation product (FDP). Although IF, FNG and FDP share same amino acid sequences, the mAb is hardly neutralised by FNG and FDP in circulation and accumulates in fibrin clots within tumour tissue. Here, we created an antibody drug conjugate (ADC) using the anti-IF mAb conjugated with a chemotherapy payload (IF-ADC). The conjugate contains a linker severed specifically by plasmin (PLM), which is activated only on binding to IF. Imaging mass spectrometry showed the substantial intratumour distribution of the payload following the IF-ADC injection into mice bearing IF-rich 5-11 xenografts derived from pancreatic tumours of LSL-KrasG12D/+; LSL-Trp53R172H/+; Ptf1a-Cre (KPC) mice. IF-ADC treatment significantly extended the survival of the KPC mice. These data suggest that conjugating chemotherapy drugs to this IF-specific mAb could represent an effective means of treating stroma-rich tumours.
Project description:In this project we establish the unit cell of fibrin polymer network by using of XL-MS methods and modelling approaches. With shotgun proteomics approach we estimate the ratio of proteins in the purified Fibrin Clots and ratio of Albumin inter- and intralinks
Project description:A goal of this project is to evaluate the integrin mRNA expression in human neural stem/progenitor cells (hNSPC) using high-throughput sequencing technologies. We found high levels of mRNA expression for the β1, α7, α3, α6, β5, αV, α5, and α9 integrins. This suggests that hNSPCs may express integrin receptors that can bind fibrinogen and laminin proteins.
Project description:Here is an ode model for in vitro fibrin matrix polymerization reproducing interactions among fibrinogen, fibrin and other proteins involved in the homeostatic phase of wound healing.