RESUMO
OBJECTIVE: The aim of this study was to observe the counter-effect of carbon monoxide-releasing molecule-2 (CORM-2) on lipopolysaccharide (LPS)-suppressed thrombomodulin (TM) and endothelial protein C receptor (EPCR) expressions from human umbilical vein endothelial cell (HUVEC), and to reveal its mechanisms. METHODS: HUVECs were divided into 5 treatment groups, wherein reagents were added simultaneously. TM and EPCR proteins of the cells and the culture medium levels of soluble TM, soluble EPCR, and matrix metalloproteinase-2 (MMP-2) were detected after administration, whereas mRNA levels of TM and EPCR, as well as nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activity among groups, were also evaluated. RESULTS: No significant difference was observed in any indicator between CORM-2 and sham groups. Addition of LPS produced drastic increase in MMP-2 expression, NF-κB activity, shedding of TM and EPCR (into the culture medium), as well as remarkable decrease in both mRNA and protein expressions of TM and EPCR, and cell viability. LPSâ+âCORM-2 treatment significantly reduced the increase in MMP-2, NF-κB activity, and TM/EPCR shedding, whereas maintained both mRNA and protein levels of TM and EPCR, and preserved cell viability. CONCLUSIONS: CORM-2 protects HUVEC from LPS-induced injury, by way of suppressing NF-κB activity, which downregulates TM and EPCR mRNAs. It also decreases MMP-2 expression and prevents the shedding of TM and EPCR from the surface of endothelial cells, so as to preserve their protective effect.
Assuntos
Anti-Inflamatórios/farmacologia , Antígenos CD/metabolismo , Fármacos Cardiovasculares/farmacologia , Compostos Organometálicos/farmacologia , Receptores de Superfície Celular/metabolismo , Trombomodulina/metabolismo , Técnicas de Cultura de Células , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Avaliação Pré-Clínica de Medicamentos , Receptor de Proteína C Endotelial , Escherichia coli , Células Endoteliais da Veia Umbilical Humana , Humanos , Lipopolissacarídeos , Metaloproteinase 2 da Matriz/metabolismo , NF-kappa B/metabolismo , RNA Mensageiro/metabolismoRESUMO
Essentials The lack of factor (F) VIIa-endothelial protein C receptor (EPCR) binding in mice is unresolved. A single substitution of Leu4 to Phe in mouse FVIIa (mFVIIa) enables its interaction with EPCR. mFVIIa with a Phe4 shows EPCR binding-dependent enhanced hemostatic function in vivo vs. mFVIIa. Defining the FVIIa-EPCR interaction in mice allows for further investigating its biology in vivo. SUMMARY: Background Human activated factor VII (hFVIIa), which is used in hemophilia treatment, binds to the endothelial protein C (PC) receptor (EPCR) with unclear hemostatic consequences. Interestingly, mice lack the activated FVII (FVIIa)-EPCR interaction. Therefore, to investigate the hemostatic consequences of this interaction in hemophilia, we previously engineered a mouse FVIIa (mFVIIa) molecule that bound mouse EPCR (mEPCR) by using three substitutions from mouse PC (mPC), i.e. Leu4âPhe, Leu8âMet, and Trp9âArg. The resulting molecule, mFVIIa-FMR, modeled the EPCR-binding properties of hFVIIa and showed enhanced hemostatic capacity in hemophilic mice versus mFVIIa. These data implied a role of EPCR in the action of hFVIIa in hemophilia treatment. However, the substitutions in mFVIIa-FMR only broadly defined the sequence determinants for its mEPCR interaction and enhanced function in vivo. Objectives To determine the individual contributions of mPC Phe4, Met8 and Arg9 to the in vitro/in vivo properties of mFVIIa-FMR. Methods The mEPCR-binding properties of single amino acid variants of mFVIIa or mPC at position 4, 8 or 9 were investigated. Results and conclusions Phe4 in mFVIIa or mPC was solely critical for interaction with mEPCR. In hemophilic mice, administration of mFVIIa harboring a Phe4 resulted in a 1.9-2.5-fold increased hemostatic capacity versus mFVIIa that was EPCR binding-dependent. This recapitulated previous observations made with triple-mutant mFVIIa-FMR. As Leu8 is crucial for hFVIIa-EPCR binding, we describe the sequence divergence of this interaction in mice, now allowing its further characterization in vivo. We also illustrate that modulation of the EPCR-FVIIa interaction may lead to improved FVIIa therapeutics.
Assuntos
Receptor de Proteína C Endotelial/química , Fator VII/química , Fator VIIa/química , Animais , Células CHO , Cricetinae , Cricetulus , DNA Complementar/metabolismo , Receptor de Proteína C Endotelial/metabolismo , Fator VII/metabolismo , Fator VIIa/metabolismo , Células HEK293 , Hemofilia A/genética , Hemostasia , Humanos , Leucina/química , Camundongos , Fenilalanina/química , Plasmídeos/metabolismo , Ligação Proteica , Domínios Proteicos , Receptores de Superfície Celular/metabolismo , Trombina/químicaRESUMO
Beyond its role in the activation of protein C, the endothelial cell protein C receptor (EPCR) plays an important role in the cytoprotective pathway. EPCR can be shed from the cell surface, which is mediated by tumor necrosis factor-[Formula: see text] converting enzyme (TACE). Pelargonidin is a well-known red pigment found in plants, and has been reported to have important biological activities that are potentially beneficial to human health. However, little is known about the effects of pelargonidin on EPCR shedding. We investigated this issue by monitoring the effects of pelargonidin on phorbol-12-myristate 13-acetate (PMA)-, tumor necrosis factor (TNF)-[Formula: see text]-, interleukin (IL)-1ß-, and cecal ligation and puncture (CLP)-mediated EPCR shedding and by investigating the underlying mechanism of pelargonidin action. Data demonstrate that pelargonidin induced potent inhibition of PMA-, TNF-[Formula: see text]-, IL-1ß-, and CLP-induced EPCR shedding by inhibiting the phosphorylation of mitogen-activated protein kinases (MAPKs) such as p38, janus kinase (JNK), and extracellular signal-regulated kinase (ERK) 1/2. Pelargonidin also inhibited the expression and activity of PMA-induced TACE in endothelial cells. These results demonstrate the potential of pelargonidin as an anti-EPCR shedding reagent against PMA- and CLP-mediated EPCR shedding.
Assuntos
Proteína ADAM17/metabolismo , Antocianinas/farmacologia , Antígenos CD/metabolismo , Inibidores Enzimáticos/farmacologia , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Receptores de Superfície Celular/metabolismo , Proteína ADAM17/antagonistas & inibidores , Proteína ADAM17/genética , Antígenos CD/genética , Regulação para Baixo/efeitos dos fármacos , Receptor de Proteína C Endotelial , MAP Quinases Reguladas por Sinal Extracelular/antagonistas & inibidores , MAP Quinases Reguladas por Sinal Extracelular/genética , Humanos , Interleucina-1beta/metabolismo , Fosforilação/efeitos dos fármacos , Receptores de Superfície Celular/antagonistas & inibidores , Receptores de Superfície Celular/genética , Acetato de Tetradecanoilforbol/farmacologia , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Diketopiperazine is a natural products found from bacteria, fungi, marine sponges, gorgonian and red algae. They are cyclic dipeptides possessing relatively simple and rigid structures with chiral nature and various side chains. The compounds in this structure class have been known to possess diverse bioactivities including antibiotic activity, anti-cancer activity, neuroprotective activity, and anti-inflammatory activity. The endothelial cell protein C receptor (EPCR) plays an important role in the cytoprotective pathway and in the activation of protein C. Endothelial cell protein C receptor (EPCR) can be shed from the cell surface, which is mediated by tumor necrosis factor-α converting enzyme (TACE). However, little is known about the effects of diketopiperazine on EPCR shedding. We investigated this issue by monitoring the effects of diketopiperazine on phorbol-12-myristate 13-acetate (PMA)-, tumor necrosis factor (TNF)-α, and interleukin (IL)-1ß-induced EPCR shedding in human umbilical vein endothelial cells (HUVECs), and cecal ligation and puncture (CLP)-mediated EPCR shedding in mice and underlying mechanism. Here, three (1-3) of diketopiperazines were isolated from two strains of marine-derived bacteria and 1-3 induced potent inhibition of PMA-, TNF-α-, IL-1ß (in HUVECs), and CLP-induced EPCR shedding (in mice) via inhibition of phosphorylation of mitogen-activated protein kinases (MAPKs) such as p38, janus kinase (JNK), and extracellular signal-regulated kinase (ERK) 1/2. 1-3 also inhibited the expression and activity of PMA-induced TACE in HUVECs suggesting that p38, ERK1/2, and JNK could be molecular targets of 1-3. These results demonstrate the potential of 1-3 as an anti-EPCR shedding reagent against PMA-mediated and CLP-mediated EPCR shedding.
Assuntos
Antígenos CD/metabolismo , Bacillus/química , Dicetopiperazinas/química , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Receptores de Superfície Celular/metabolismo , Proteínas ADAM/metabolismo , Proteína ADAM17 , Animais , Receptor de Proteína C Endotelial , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Interleucina-1beta , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Quinases Ativadas por Mitógeno/antagonistas & inibidores , Água do Mar/microbiologia , Sepse/metabolismo , Acetato de Tetradecanoilforbol , Fator de Necrose Tumoral alfaRESUMO
Beyond its role in the activation of protein C, the endothelial cell protein C receptor (EPCR) plays an important role in the cytoprotective pathway. EPCR can be shed from the cell surface, which is mediated by tumor necrosis factor-α converting enzyme (TACE). Polyozellin, a major constituent of a Korea edible mushroom Polyozellus multiplex, has been known to exhibit the biological activities such as anti-oxidative and anti-inflammatory effects. However, little is known about the effects of polyozellin on EPCR shedding. We investigated this issue by monitoring the effects of polyozellin on phorbol-12-myristate 13-acetate (PMA)-, tumor necrosis factor (TNF)-α-, interleukin (IL)-1ß-induced EPCR shedding in human umbilical vein endothelial cells (HUVECs), and cecal ligation and puncture (CLP)-mediated EPCR shedding in mice and underlying mechanism. Data demonstrate that polyozellin induced potent inhibition of PMA-, TNF-α-, IL-1ß- (in HUVECs), and CLP-induced EPCR shedding (in mice) via inhibition of phosphorylation of mitogen-activated protein kinases (MAPKs) such as p38, janus kinase (JNK), and extracellular signal-regulated kinase (ERK) 1/2. Polyozellin also inhibited the expression and activity of PMA-induced TACE in HUVECs suggesting that p38, ERK1/2, and JNK could be the molecular targets of POZ. These results demonstrate the potential of polyozellin as an anti-EPCR shedding reagent against PMA-mediated and CLP-mediated EPCR shedding.
Assuntos
Proteínas ADAM/antagonistas & inibidores , Agaricales/química , Antígenos CD/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/antagonistas & inibidores , Furanos/química , Receptores de Superfície Celular/metabolismo , Proteína ADAM17 , Animais , Modelos Animais de Doenças , Receptor de Proteína C Endotelial , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Interleucina-1beta/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Sepse/metabolismo , Acetato de Tetradecanoilforbol/farmacologia , Fator de Necrose Tumoral alfa/farmacologiaRESUMO
Despite years of research and efforts to translate stroke research to clinical therapy, ischaemic stroke remains a major cause of death, disability, and diminished quality of life. Primary and secondary preventive measures combined with improved quality of care have made significant progress. However, no novel drug for ischaemic stroke therapy has been approved in the past decade. Numerous studies have shown beneficial effects of activated protein C (APC) in rodent stroke models. In addition to its natural anticoagulant functions, APC conveys multiple direct cytoprotective effects on many different cell types that involve multiple receptors including protease activated receptor (PAR) 1, PAR3, and the endothelial protein C receptor (EPCR). Application of molecular engineered APC variants with altered selectivity profiles to rodent stroke models demonstrated that the beneficial effects of APC primarily require its cytoprotective activities but not its anticoagulant activities. Extensive basic, preclinical, and clinical research provided a compelling rationale based on strong evidence for translation of APC therapy that has led to the clinical development of the cytoprotective-selective APC variant, 3K3A-APC, for ischaemic stroke. Recent identification of non-canonical PAR1 and PAR3 activation by APC that give rise to novel tethered-ligands capable of inducing biased cytoprotective signalling as opposed to the canonical signalling provides a mechanistic explanation for how APC-mediated PAR activation can selectively induce cytoprotective signalling pathways. Collectively, these paradigm-shifting discoveries provide detailed insights into the receptor targets and the molecular mechanisms for neuroprotection by cytoprotective-selective 3K3A-APC, which is currently a biologic drug in clinical trials for ischaemic stroke.
Assuntos
Isquemia Encefálica/tratamento farmacológico , Fármacos Neuroprotetores/uso terapêutico , Proteína C/uso terapêutico , Animais , Antígenos CD/fisiologia , Coagulação Sanguínea , Isquemia Encefálica/epidemiologia , Ensaios Clínicos como Assunto , Avaliação Pré-Clínica de Medicamentos , Receptor de Proteína C Endotelial , Endotélio Vascular/fisiopatologia , Ativação Enzimática , Hemorragia/prevenção & controle , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Modelos Biológicos , Modelos Moleculares , Proteína C/metabolismo , Proteína C/farmacologia , Conformação Proteica , Receptores de Superfície Celular/fisiologia , Receptores Ativados por Proteinase/fisiologia , Proteínas Recombinantes/farmacologia , Proteínas Recombinantes/uso terapêutico , Transdução de Sinais/efeitos dos fármacos , Trombina/farmacologia , Trombina/fisiologia , Ativador de Plasminogênio Tecidual/efeitos adversos , Ativador de Plasminogênio Tecidual/uso terapêuticoRESUMO
Endothelial cell protein C receptor (EPCR) plays an important role in coagulation and inflammation. EPCR can be shed from the cell surface, and this is mediated by tumor necrosis factor-α-converting enzyme (TACE). Piperlonguminine (PL), an important component of Piper longum fruits, is known to exhibit antihyperlipidemic, antiplatelet, and antimelanogenesis activities. However, little is known about the effects of PL on EPCR shedding. Here, we investigated this issue by monitoring the effects of PL on phorbol-12-myristate 13-acetate (PMA) and on cecal ligation and puncture (CLP)-mediated EPCR shedding and underlying mechanisms. PL induced potent inhibition of PMA, and CLP induced EPCR shedding through suppression of TACE expression. And treatment with PL resulted in reduced PMA-stimulated phosphorylation of p38, extracellular regulated kinases (ERK) 1/2, and c-Jun N-terminal kinase (JNK). Given these results, PL might have potential as an anti-sEPCR shedding reagent against PMA- and CLP-mediated EPCR shedding.
Assuntos
Anti-Inflamatórios/farmacologia , Antígenos CD/efeitos dos fármacos , Dioxolanos/farmacologia , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Extratos Vegetais/farmacologia , Receptores de Superfície Celular/efeitos dos fármacos , Sepse/tratamento farmacológico , Proteínas ADAM/metabolismo , Proteína ADAM17 , Animais , Antígenos CD/metabolismo , Células Cultivadas , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Receptor de Proteína C Endotelial , Ativação Enzimática , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Frutas , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Interleucina-6/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fosforilação , Fitoterapia , Piper , Plantas Medicinais , Receptores de Superfície Celular/metabolismo , Sepse/metabolismo , Sepse/microbiologia , Acetato de Tetradecanoilforbol/farmacologia , Fatores de Tempo , Fator de Necrose Tumoral alfa/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
Metabolic syndrome is associated with significant hypercoagulable prothrombotic tendency; however, the mechanism for the prothrombotic state is not completely understood. We hypothesize that higher circulating plasma free fatty acids (FFAs) in metabolic syndrome inhibit the endothelial thrombomodulin (TM)-endothelial protein C receptor (EPCR) pathway, thereby promoting thrombus formation. Human umbilical vein endothelial cells were cultured in media supplemented with various doses of palmitic acid (PA), in the presence or absence of JNK inhibitor, and the expression of TM and EPCR was measured by western blot. The thrombotic state of high fat fed C57BL/6J mice was examined by tail bleeding time and deep venous thrombosis (DVT) model. As a result, PA inhibited the expression of TM and EPCR in endothelial cells, and this effect was blunted by inhibiting JNK signaling. High fat diet fed mice had higher level of circulating FFAs and exhibited prothrombotic state, evidenced by increased tail bleeding time and enlarged thrombotic size in DVT model, compared to the control diet fed mice. Hence, FFAs inhibit TM-EPCR-Protein C system in endothelial cells through activating JNK signaling, which may be a mechanism for the prothrombotic state in metabolic syndrome.
Assuntos
Antígenos CD/biossíntese , Ácidos Graxos não Esterificados/metabolismo , Regulação da Expressão Gênica , Células Endoteliais da Veia Umbilical Humana/metabolismo , MAP Quinase Quinase 4/metabolismo , Síndrome Metabólica/metabolismo , Receptores de Superfície Celular/biossíntese , Transdução de Sinais , Trombomodulina/biossíntese , Trombose Venosa/metabolismo , Animais , Tempo de Sangramento , Células Cultivadas , Gorduras na Dieta/efeitos adversos , Gorduras na Dieta/farmacologia , Receptor de Proteína C Endotelial , Células Endoteliais da Veia Umbilical Humana/patologia , Humanos , Masculino , Síndrome Metabólica/complicações , Síndrome Metabólica/patologia , Camundongos , Trombose Venosa/etiologia , Trombose Venosa/patologiaRESUMO
Sepsis is defined as a systemic response to infection, characterized by an intense inflammatory response linked to coagulation activation and fibrinolysis inhibition, two processes which are intimately associated. In a field where mortality remains very high, administration of activated protein C, a physiological coagulation inhibitor with cytoprotective properties, has demonstrated its effectiveness and was able to reduce mortality. Protein C belongs to a system that involves plasma proteins and endothelial cell receptors. In addition to well documented effects on coagulation and fibrinolysis, activated protein C exhibits anti-inflammatory, anti-apoptotic but also anti-histone activities. Indeed, a recent study focusing on the cytoprotective effects of activated protein C showed that extracellular histones are released during severe sepsis and may participate in the pathophysiology of severe sepsis. These histones appear to be new targets of activated protein C.
Assuntos
Coagulação Sanguínea/fisiologia , Inflamação/sangue , Proteína C/fisiologia , Sepse/fisiopatologia , Animais , Anti-Inflamatórios não Esteroides/uso terapêutico , Anticoagulantes/uso terapêutico , Antígenos CD/fisiologia , Fatores de Coagulação Sanguínea/fisiologia , Ensaios Clínicos como Assunto , Desenho de Fármacos , Avaliação Pré-Clínica de Medicamentos , Receptor de Proteína C Endotelial , Endotélio Vascular/fisiopatologia , Ativação Enzimática , Fibrinólise , Transtornos Hemorrágicos/induzido quimicamente , Histonas/antagonistas & inibidores , Histonas/metabolismo , Humanos , Inflamação/tratamento farmacológico , Migração e Rolagem de Leucócitos/efeitos dos fármacos , Modelos Biológicos , Estudos Multicêntricos como Assunto , Proteína C/efeitos adversos , Proteína C/farmacologia , Proteína C/uso terapêutico , Receptor PAR-1/efeitos dos fármacos , Receptor PAR-1/fisiologia , Receptores de Superfície Celular/fisiologia , Proteínas Recombinantes de Fusão/efeitos adversos , Proteínas Recombinantes de Fusão/uso terapêutico , Sepse/sangue , Sepse/tratamento farmacológicoRESUMO
Although thromboembolism is a problematic complication of chemotherapy, the pathogenic mechanisms by which chemotherapeutic agents exert prothrombotic effects in vivo are unclear.The objective of this study was to examine the effects of adjuvant chemotherapy on thrombin generation, the protein C anticoagulant pathway, and microparticle tissue factor (MP TF) activity in 26 breast cancer patients (stages I to III). The patients received cyclophosphamide, 5-fluorouracil, and methotrexate, epirubicin, or doxorubicin. Plasma samples were collected on day 1 (baseline), day 2, and day 8 for the first 2 cycles of chemotherapy. Levels of thrombin-antithrombin (TAT) complexes, MP TF activity, and components of the protein C anticoagulant pathway, including protein C, activated protein C (APC), soluble thrombomodulin (sTM), and soluble endothelial protein C receptor (sEPCR), were measured. Compared to prechemotherapy baseline levels, plasma TAT, protein C, and APC were significantly different following the administration of chemotherapy (p < 0.01 for each). Plasma TAT was higher in cycle 1, day 2, and cycle 2, day 8, compared to baseline. Plasma protein C levels were lower in cycle 2, day 8, whereas plasma APC levels were lower in cycle 2, day 1, and cycle 2, day 8. No significant changes were found in plasma sEPCR, sTM, or MP TF activity. This study suggests that adjuvant chemotherapy in women with breast cancer increases thrombin generation and impairs the endothelium-based protein C anticoagulant pathway.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Neoplasias da Mama/sangue , Neoplasias da Mama/tratamento farmacológico , Proteína C/metabolismo , Trombina/metabolismo , Adulto , Antígenos CD/sangue , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Antitrombina III , Ciclofosfamida/administração & dosagem , Ciclofosfamida/efeitos adversos , Doxorrubicina/administração & dosagem , Doxorrubicina/efeitos adversos , Receptor de Proteína C Endotelial , Epirubicina/administração & dosagem , Epirubicina/efeitos adversos , Feminino , Fluoruracila/administração & dosagem , Fluoruracila/efeitos adversos , Humanos , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Peptídeo Hidrolases/sangue , Receptores de Superfície Celular/sangue , Trombomodulina/sangue , Tromboplastina/metabolismo , Trombose/sangue , Trombose/induzido quimicamente , Fatores de TempoRESUMO
Sepsis remains the leading cause of death in intensive care units. Uncontrolled systemic inflammation and an impaired protein C pathway are two important contributors to sepsis pathophysiology. Based on the beneficial effects of the saponin fraction from Astragalus membranaceus roots (SAM) against inflammation, liver dysfunction, and endothelium injury, we investigated the potential protective roles and underlying mechanisms of SAM on polymicrobial sepsis induced by cecal ligation and puncture (CLP) in mice. SAM, orally administered 1 h before and after CLP, significantly elevated the survival rate of mice. At 96 h after CLP operation, all mice in the model group died, whereas 33.3% of mice in the SAM (400 mg/kg)-treated group survived. SAM attenuated both inflammatory factors and their abilities to induce tissue dysfunction, which was mainly evidenced by decreased infiltration of polymorphonuclear leukocytes, tissue edema, and lung wet-to-dry weight ratio, lowered levels of myeloperoxidase (MPO), nitric oxide (NO), lactate dehydrogenase (LDH), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) in serum, as well as downregulated expressions of iNOS and IL-1beta mRNA in livers. Furthermore, we addressed the effects of SAM on the protein C (PC) pathway, closely linked with sepsis. In CLP-induced septic mice, SAM elevated the impaired expression of PC mRNA in livers. In vitro, SAM reversed the decreased expressions of thrombomodulin (TM) and endothelial PC receptor (EPCR) mRNA induced by lipopolysaccharide (LPS) in endothelial cells. These findings suggest that SAM is able to restore the impaired protein C pathway. Taken together, the current study demonstrates that SAM has protective effects on polymicrobial sepsis in mice. The mechanisms of action involve anti-inflammation and upregulation of the PC pathway.