Search Results (185)

Tumor metastasis is closely associated with coagulation and inflammation, particularly via thrombin–PAR1 signaling. However, the potential of natural polysaccharides such as rhamnan sulfate (RS) to modulate these pathways and suppress metastasis remains unclear. We aimed to investigate the effects of orally administered RS derived from Monostroma nitidum on melanoma metastasis and its underlying mechanisms. Male C57BL/6J mice were orally administered water or RS daily. On day 8, saline or B16 melanoma cells were injected intravenously. Mice were treated for 21 days and divided into four groups (control, RS-only, M + W, and M + RS; n = 5/group). Metastasis and related molecular factors were analyzed in plasma, lung, and aortic tissues. Significant lung and aortic metastases were observed in the M + W group but were markedly suppressed in the M + RS group. RS reduced the expression of inflammatory factors (e.g., IL-6, PAR1), proteases, leukocyte activation markers, complement factors, angiogenic factors, and EMT-related factors. Conversely, thrombin, thrombomodulin, plasmin, TAFIa, and tight junction proteins were increased in RS-treated mice. RS suppresses melanoma metastasis by modulating thrombin–PAR1-mediated inflammation and associated pathways. These findings suggest RS as a potential therapeutic agent, although further mechanistic and clinical studies are required. Full article

The objective of the present study is to evaluate the effects of lactation stage, age, somatic cell count (SCC), and daily milk yield on plasmin–plasminogen (PL–PG) system activity and physicochemical milk traits in intensively reared Chios and Frizarta ewes. A total of 52 purebred ewes (26 ewes per breed and farm) were randomly selected and prospectively monitored during the 3rd, 5th, and 6th month post-lambing. Daily milk yield and body condition score (BCS) were recorded, and individual milk samples were collected for the assessment of PL–PG activities using enzymatic assays, SCC, electrical conductivity (EC), refractive index (RI), and pH. Correlation analysis and mixed linear regression models were used for the assessment of the effects. Lactation stage significantly affected PL–PG system traits in both breeds, but in opposite direction; plasmin and plasminogen plus plasmin declined toward late lactation in Chios ewes, whereas it increased in Frizarta ewes. Lower SCC was associated with reduced plasmin system activity in Chios ewes, whereas no effect was observed in Frizarta ewes. The plasminogen-to-plasmin ratio remained stable across lactation, breeds, and SCC classes, indicating coordinated regulation of the system. BCS was positively associated with plasmin activity during late lactation, suggesting a stage-dependent metabolic modulation. EC and pH were closely associated with SCC, while RI mainly reflected compositional variation. Our findings underline that, although the PL–PG system is primarily affected by lactation stage and mammary health status in sheep, there are breed-specific regulatory patterns which should be further investigated. Full article

The SERPINE1 gene encodes the serine protease inhibitor plasminogen activator inhibitor type-1 (PAI-1), a major negative regulator of the plasmin-dependent pericellular proteolytic cascade and a crucial determinant in the program of stromal remodeling. Recent omics approaches confirmed that high tumor SERPINE1 levels are prognostic for poor disease outcomes and shorter disease-free survival in various malignancies. Kinetic analysis of biomarkers of cell cycle transit in growth-synchronized p53 dual mutant human keratinocytes confirmed that PAI-1 transcription occurred early after growth activation of quiescent (G₀) cells and prior to G1 entry. Previous evidence has confirmed that differential residence of USF family members (USF1→USF2 switch) at the PE2 region hexanucleotide E box motif (CACGTG) in the SERPINE1 proximal promoter characterizes the G₀→G₁ transition period and the transcriptional status of the SERPINE1 gene. A consensus PE2 E box motif (5′-CACGTG-3′) at nucleotides −566 to −561 is required for USF occupancy of the PE2 E box and serum-stimulated SERPINE1 transcription. Interference with USF2 occupancy of the PE2 E Box site by a double-stranded PE2 “decoy”, or induced expression of a dominant-negative USF (A-USF) construct, attenuate serum- and TGF-β1-stimulated SERPINE1 synthesis. Tet-Off activation of an A-USF insert reduced both PAI-1 and PAI-2 transcripts while increasing the fraction of proliferating (Ki-67⁺ cells). Conversely, overexpression of USF2 or adenoviral delivery of a PAI-1 vector inhibited HaCaT colony expansion. These findings are discussed in this review and collectively suggest that the USF1→USF2 transition at the PE2 E box site and subsequent SERPINE1 transcription impact serum-stimulated keratinocyte growth and, likely, cell cycle progression. Full article

Leptospirosis is a widespread zoonosis of human and veterinary concern. The etiological agent of the disease is the pathogenic bacteria of the genus Leptospira. Transmission typically occurs through mucosal contact and/or injured skin with the urine of infected animals or contaminated environmental sources. Understanding the biology and pathogenesis of leptospires is the main focus of our study. In this work, we characterized a novel protein encoded by the LIC_13056 gene from L. interrogans serovar Copenhageni, having an OmpA-like domain. We show that this coding sequence (CDS), previously assigned as a hypothetical protein with an unknown function, is capable of binding to the cellular receptor α8 integrin subunit, potentially contributing to kidney colonization. Additionally, the protein bound to both purified and normal human serum (NHS) plasminogen (PLG). In both conditions, PLG bound to protein was able to generate plasmin (PLA). Furthermore, rLIC_13056 interacted with the complement system components C4b, C4BP, C8 and C9. The interaction of recombinant protein to the C9 had a negative impact on C9 polymerization. Taken together, the protein LIC_13056, having an OmpA-like domain, appears to be involved in leptospiral pathogenesis via different stages of the infection process; PLA generation together with the inhibition of the membrane attack complex (MAC) may contribute to the immune evasion mechanism of Leptospira, thus facilitating the infection. Full article

Background: In the treatment of ischemic stroke, both tissue-type plasminogen activator (t-PA) thrombolytic and endovascular therapy are employed; however, delayed intervention with these therapies increases the risk of hemorrhage. Hemorrhage associated with delayed t-PA treatment involves the activation of plasmin and matrix metalloproteinases (MMPs); however, the detailed mechanisms underlying I/R activation remain unclear. Objectives: This study examined the effects of delayed recanalization on ischemic stroke in a permanent middle cerebral artery (MCA) occlusion (MCA-O) model, and a novel MCA ischemia/reperfusion (I/R) model: 2-h ischemia followed by reperfusion (I/R 2 h), and 4.5-h ischemia followed by reperfusion (I/R 4.5 h). Secondary induced thrombus (SIT) formation, hemorrhage, MMP activity, MMP-9 immunoreactivity, and tomato lectin (TL) staining, as well as the effects of t-PA and heparin treatment were evaluated. Results: SIT formed within 1 h after reperfusion in the I/R 4.5 h model only, while t-PA or heparin treatment reduced SIT formation. Hemorrhage increased with or without t-PA administration in the I/R 4.5 h model, but it was suppressed by heparin pretreatment. MMP activity and MMP-9 immunoreactivity were localized to the SIT. Additionally, a negative staining area for TL was observed in the damaged area, where SIT formed in the I/R 4.5 h model. Conclusions: These results suggest that delayed recanalization induces SIT via glycocalyx degradation, leading to hemorrhage via plasmin/MMP-9 activation by endogenous and exogenous t-PA-mediated fibrinolysis in novel murine models of ischemic stroke. Furthermore, inhibition of SIT formation is beneficial for suppressing hemorrhages associated with delayed recanalization after endovascular or t-PA therapy. Full article

The intestine is considered a habitat for both bacteria and parasites. In this study, many fecal bacterial isolates and the protozoan Blastocystis sp. were recovered from stool samples of individuals with gastrointestinal conditions. Isolated bacteria were tested for extracellular protease production, and the most potent producer was identified by 16SrDNA gene sequencing as P. aeruginosa FZM498. The enzyme was extracted and purified to electrophoretic homogeneity by the DEAE-Sepharose ion-exchanger and SDS-PAGE revealed a major band at 42.15 KDa. It exhibited maximal activity at 35 °C with thermostability at 60 °C (T_1/2 = 200.04 min). It was most active at pH 8.0 and stable at 5.0–9.5. Enzymatic activity was greatly stimulated in the presence of Fe²⁺ ions, but was repressed by Zn²⁺ and Hg²⁺ ions. Inhibition by PMSF, TLCK, aprotinin, benzamidine, and SBTI protease reagents suggests a serine protease family. The V_max and K_m dynamic constants against azocasein were 36.232 U/mL and 0.0072 mM, respectively. It exhibited the lowest K_m value against the synthetic substrate D-Val-Leu-Lys-pNA among all substrates, indicating a plasmin-like activity. Interestingly, when tested against Blastocystis sp., cysts appeared progressively shrunken, ruptured, and mycelial-like, indicating complete structural collapse with leakage of intracellular contents. The importance of this research is that it is the first study to test the anti-Blastocystis activity of an extracted bacterial serine protease from the gut. This could be a promising, eco-friendly, natural alternative as an anti-Blastocystis agent. The objective of this study was to isolate, purify, and biochemically characterize an extracellular serine protease produced by gut-associated bacteria, as well as to assess its in vitro anti-Blastocystis efficacy as a potential natural and ecologically friendly antiparasitic therapy. Full article

The premetastatic niche (PMN) represents a specialized microenvironment established in distant organs before the arrival of metastatic cells. This concept has fundamentally altered our understanding of cancer progression, shifting it from a random event-driven process to an orchestrated one. This review examines the critical role of extracellular proteases in PMN formation, focusing on matrix metalloproteinases (MMPs), serine proteases, and cysteine cathepsins that collectively orchestrate extracellular matrix remodeling, immune modulation, and vascular permeability changes essential for metastatic colonization. Key findings demonstrate that MMP9 and MMP2 facilitate basement membrane degradation and the recruitment of bone marrow-derived cells. At the same time, tissue inhibitor of metalloproteinase-1 (TIMP-1) promotes organ-specific hepatic PMN recruitment through neutrophil recruitment mechanisms. The plasminogen–plasmin system emerges as a master regulator through its broad-spectrum proteolytic activity and ability to activate downstream proteases, with S100A10-mediated plasmin generation providing mechanistic pathways for remote PMN conditioning. Neutrophil elastase and cathepsin G contribute to the degradation of anti-angiogenic proteins, thereby creating pro-metastatic microenvironments. These protease-mediated mechanisms represent the earliest interventional window in metastatic progression, offering therapeutic potential to prevent niche formation rather than treat established metastases. However, significant methodological challenges remain, including the need for organ-specific biomarkers, improved in vivo methods for measuring protease activity, and a better understanding of temporal PMN dynamics across different target organs. Full article

Even when people with diabetes mellitus (DM) meet their cholesterol goals, they still face a higher risk of heart and blood vessel problems. One major reason is a particle called lipoprotein(a), or Lp(a), which is similar to LDL cholesterol. Raised levels of Lp(a) are inherited rather than caused by lifestyle. Lp(a) can build up in the body and make it easier for blood clots to form because it closely resembles a protein called plasminogen, reducing its ability to form plasmin that dissolves blood clots. At the same time, chemical changes like oxidation and glycation can make blood vessels more inflamed, adding to the risk. Elevated concentrations of Lp(a) (>30 mg/dL; 75 nmol/L), and particularly >50 mg/dL (125 nmol/L), are independently associated with coronary artery disease, ischemic stroke, diabetic nephropathy, retinopathy, and neuropathy. Conventional lipid-lowering therapies exert neutral or modest effects on Lp(a), in contrast to RNA-based targeted agents (antisense oligonucleotides and siRNA [Small Interfering RNA]), which achieve reductions of 70–95% and show consistent results in Phase 2 clinical trials. In this review, we bring together findings from laboratory research and clinical studies, and highlight why it is important to measure Lp(a) levels—at least once in a person’s life, and especially in those with diabetes—to help doctors better assess risk and plan more effective treatments. In diabetic populations, the adaptation of Lp(a)-targeted therapies could redefine the management of residual risk and improve both cardiovascular and microvascular outcomes. Full article

Autoimmune diseases arise from complex interactions of genetic, environmental, and hormonal factors, yet their precise causes remain elusive. Beyond its canonical role in fibrin degradation, the fibrinolytic system is increasingly recognized as both a pathogenic driver and a regulatory modulator in autoimmunity. Key factors—plasminogen (Plg), plasmin, α2-antiplasmin (α2AP), tissue-type plasminogen activator (tPA), urokinase-type plasminogen activator (uPA), its receptor (uPAR), and plasminogen activator inhibitor-1 (PAI-1)—not only reflect secondary responses to vascular and immune dysregulation but also actively shape innate and adaptive immunity. They influence macrophage activation, dendritic cell maturation, T cell responses, and cytokine production, thereby bridging coagulation, inflammation, and tissue repair. This review integrates current evidence on the dual pathogenic and regulatory roles of fibrinolytic factors, organizing autoimmune diseases into systemic, organ-specific, and secondary syndromes. We further discuss how the imbalance of fibrinolysis can either promote inflammatory persistence or, conversely, facilitate resolution through fibrin clearance and immune homeostasis. By highlighting this bidirectional influence, the review aims to refine our understanding of fibrinolytic components as both contributors to and regulators of autoimmune disease pathogenesis. Full article

Background: Fibrinolytic impairment is one of the key factors involved in the pathogenesis of hemostasis disturbances in sepsis, significantly contributing to microthrombosis, organ dysfunction, and mortality rates. While hemostatic assessment in sepsis typically focuses on coagulation activation, evaluating fibrinolytic activity remains challenging due to methodological limitations and a lack of standardization of the currently available methods. Objectives: This comprehensive review examines current methods for assessing fibrinolytic activity in bacterial sepsis, their clinical applications, strengths and limitations, and future perspectives for improved diagnostic approaches. Methods: We conducted a systematic literature search and identified 52 studies that investigated fibrinolysis assessment in adult patients with bacterial sepsis using biomarkers or global tests. Studies included mainly observational cohorts examining various fibrinolytic assessment methods. Results: Fibrinolytic shutdown, primarily mediated by the overproduction of plasminogen activator inhibitor-1 (PAI-1), occurs early in sepsis and correlates with disease severity and mortality. Current assessment methods include plasma biomarker measurements (PAI-1, plasmin-antiplasmin complexes, D-dimer), global plasma-based tests (clot lysis time, plasmin generation assays), and whole-blood viscoelastic testing (rotational thromboelastometry, ROTEM; thromboelastography, TEG). Modified viscoelastic tests incorporating tissue plasminogen activators demonstrate enhanced sensitivity for detecting fibrinolytic resistance. Despite efforts, standardization is still limited, and routine clinical implementation has not been achieved yet. Conclusions: Fibrinolytic assessment provides important prognostic information in sepsis, despite methodological challenges. The integration of point-of-care viscoelastic testing with modified protocols shows promise for real-time evaluation. Future research should focus on developing standardized, automated assays suitable for routine clinical practice, enabling personalized therapeutic interventions that target fibrinolytic dysfunction in sepsis. Full article

Alpha2-plasmin inhibitor (α2PI) has a heterogeneous structure due to proteolytic cleavages in the circulation. The C-terminally cleaved form loses the plasminogen binding site and is, therefore, a slow plasmin inhibitor (NPB-α2PI). As FXIII primarily crosslinks the plasminogen-binding intact form (PB-α2PI) to fibrin, the effect of NPB-α2PI on fibrinolysis has been less studied. Herein, we investigated the effect of C-terminal truncation. Total-, PB-, and NPB-α2PI antigen levels and α2PI incorporation were measured by ELISAs from samples of 80 healthy individuals. Clot lysis parameters of the same subjects were investigated using an in vitro clot lysis assay. α2PI incorporation into the clot was demonstrated by Western blotting. Clot lysis and clot structure were also analyzed using an α2PI-deficient plasma substituted with recombinant PB- and NPB-α2PI. Both plasma and clot-bound levels of total- and NPB-α2PI showed a significant positive correlation with clot lysis parameters. NPB-α2PI was detected in the clot due to non-covalent binding. Regardless of the type of binding, both forms affected the clot structure by increasing the thickness of the fibrin fibers and reducing the pore size. In conclusion, we found that NPB-α2PI can bind non-covalently to fibrin, and this binding contributes to changes in clot structure and inhibition of fibrinolysis. Full article

Background/Objectives: We define severe postpartum hemorrhage (PPH) with macroscopic hematuria as clinical disseminated intravascular coagulation (DIC), a life-threatening condition. We also report a methodology using machine learning, a subtype of artificial intelligence, for developing the boundary criterion for predicting hematuria on the fibrinogen–fibrin/fibrinogen degradation product (FDP) plane. A positive FDP–fibrinogen/3–60 (mg/dL) value indicates hematuria; otherwise, non-hematuria is observed. We aimed to validate this criterion using severe placental abruption (PA), and to examine the activation of the coagulation–fibrinolytic system in clinical DIC. Methods: Of 17,285 deliveries across nine perinatal centers in Japan between 2020 and 2024, 13 had severe PA without hematuria, 18 had severe PPH without hematuria, and 3 had severe PPH with hematuria, i.e., clinical DIC. We calculated the values of the criterion formula for 13 cases of severe PA to validate the boundary criterion and compared the laboratory tests for coagulation–fibrinolytic activation among the three groups. Results: The calculated values using the criterion for the 13 PA without hematuria ranged from −108.91 to −5.87 and all were negative. In cases of clinical DIC, fibrinogen levels (median, 62 mg/dL) were lower (p < 0.05), while levels of FDP (96 mg/dL), the thrombin–antithrombin complex (120 ng/mL), and the plasmin-α₂–plasmin inhibitor complex (28.4 μg/mL) were significantly higher than in the other two groups. Conclusions: This study demonstrated the validity of the boundary criterion for predicting hematuria using severe PA. The coagulation–fibrinolytic test results suggested that PPH cases with hematuria were assumed to have clinical DIC, indicating that this criterion may be considered for diagnosing DIC during delivery. However, further additional patient data are needed to confirm the usefulness of this criterion because of the very low number of hematuria cases. Full article

Background/Objectives: CD318 (also known as CDCP1) is a transmembrane protein that is overexpressed in many cancers and contributes to tumor progression, invasion, and metastasis by activating SRC family kinases through phosphorylation. Emerging evidence also suggests that CD318 plays a role in modulating the tumor immune microenvironment, although its precise mechanism in tumor progression is still not well understood. Methods: To investigate this, we analyzed the expression and immune-related functions of CD318 using the publicly available data from The Cancer Genome Atlas (TCGA) across colorectal adenocarcinoma (COAD), cervical squamous cell carcinoma (CESC), lung adenocarcinoma (LUAD), and pancreatic adenocarcinoma (PAAD). Results: All four cancers exhibited a high level of CD318 expression. Notably, in CESC, LUAD, and PAAD, plasmin-mediated cleavage of CD318 leads to phosphorylation of SRC and protein kinase C delta (PKCδ), which activates HIF1α and/or p38 MAPK. These downstream effectors translocate to the nucleus and promote the transcriptional upregulation of TGFβ1, fostering an immunosuppressive tumor microenvironment through Treg cell recruitment. In contrast, this signaling cascade appears to be absent in COAD. Instead, our analysis indicate that intact CD318 in COAD interacts with the surface receptors CD96 and CD160, which are found on CD8⁺ T cells and NK cells. Conclusions: This interaction enhances cytotoxic immune responses in COAD by promoting CD8⁺ T cell and NK cell activity, offering a possible explanation for the favorable prognosis associated with high CD318 expression in COAD, compared to the poorer outcomes observed in CESC, LUAD, and PAAD. Full article

The fibrin matrix of thrombi is intertwined with neutrophil extracellular traps (NETs) containing histones that render resistance to fibrinolysis. During NET formation, histones are citrullinated. Our study addresses the question of whether citrullination modifies the fibrin-stabilizing effects of histones. We studied the structure and viscoelastic properties of fibrin formed in the presence of native or citrullinated H1 and core histones by scanning electron microscopy, clot permeation, and oscillation rheometry. The kinetics of fibrin formation and its dissolution were followed by turbidimetry and thromboelastometry. Co-polymerizing H1 with fibrin enhanced the mechanical strength of the clots, thickened the fibrin fibers, and enlarged the gel pores. In contrast, the addition of core histones resulted in a reduction in the fiber diameter, and the pores were only slightly larger, whereas the mechanical stability was not modified. Plasmin-mediated fibrinogen degradation was delayed by native and citrullinated core histones, but not by H1, and the action of des-kringle1-4-plasmin was not affected. Plasmin-mediated fibrinolysis was inhibited by native and citrullinated core histones, and this effect was moderated when the kringle domains of plasmin were blocked or deleted. These findings suggest that in NET-containing thrombi that are rich in core histones, alternative fibrinolytic enzymes lacking kringle domains are more efficient lytic agents than the classic plasmin-dependent fibrinolysis. Full article

The discovery of carbon monoxide releasing molecules (CORMs) was one of the most impactful innovations in biochemistry, affecting multiple disciplines for the past few decades. Sixteen years ago, a ruthenium dimer-containing CORM, CORM-2, enhanced coagulation and diminished fibrinolysis in human plasma by modulation of fibrinogen, plasmin, and α₂-antiplasmin via CO binding to putative heme groups attached to these proteins. This finding linked CO exposure in settings involving heme oxygenase-1 upregulation during inflammation or environmental exposure to thromboembolic disease in hundreds of subsequent manuscripts. However, CO-independent effects of CORM-2 involving a putative ruthenium radical (Ru•) formed during CO release was found to be responsible for many of effects by CORM-2 in other works. Using a novel approach with human plasmatic coagulation kinetic methods, Ru• was posited to bind to critical histidines and other amino acids to modulate function, and excess histidine to quench CORM-2-mediated effects. This paradigm of histidine addition would definitively address if CO or Ru• was responsible for CORM-2-mediated effects. Thus, plasma coagulation/fibrinolytic kinetic data were assessed via thrombelastography ±CORM-2, ±histidine added. Histidine nearly completely abrogated CORM-2-mediated hypercoagulation in a concentration-dependent fashion; further, histidine also nearly eliminated all kinetic effects on fibrinolysis. In conclusion, CORM-2 Ru• formation, not CO release, is the true molecular mechanism modulating coagulation and fibrinolysis. Full article