-
Virology Feb 2018Efferocytosis, the phagocytic clearance of apoptotic cells, can provide host protection against certain types of viruses by mediating phagocytic clearance of infected...
Efferocytosis, the phagocytic clearance of apoptotic cells, can provide host protection against certain types of viruses by mediating phagocytic clearance of infected cells undergoing apoptosis. It is known that HIV-1 induces apoptosis and HIV-1-infected cells are efferocytosed by macrophages, although its molecular mechanisms are unknown. To elucidate the roles that efferocytosis of HIV-1-infected cells play in clearance of infected cells, we sought to identify molecules that mediate these processes. We found that protein S, present in human serum, and its homologue, Gas6, can mediate phagocytosis of HIV-1-infected cells by bridging receptor tyrosine kinase Mer, expressed on macrophages, to phosphatidylserine exposed on infected cells. Efferocytosis of live infected cells was less efficient than dead infected cells; however, a significant fraction of live infected cells were phagocytosed over 12h. Our results suggest that efferocytosis not only removes dead cells, but may also contribute to macrophage removal of live virus producing cells.
Topics: Animals; HIV Infections; HIV-1; Humans; Intercellular Signaling Peptides and Proteins; Macrophages; Phagocytosis; Protein S
PubMed: 29304470
DOI: 10.1016/j.virol.2017.12.025 -
Plant & Cell Physiology Jan 2020Nitric oxide (NO) is a crucial signaling molecule that conveys its bioactivity mainly through protein S-nitrosylation. This is a reversible post-translational...
Nitric oxide (NO) is a crucial signaling molecule that conveys its bioactivity mainly through protein S-nitrosylation. This is a reversible post-translational modification (PTM) that may affect protein function. S-nitrosoglutathione (GSNO) is a cellular NO reservoir and NO donor in protein S-nitrosylation. The enzyme S-nitrosoglutathione reductase (GSNOR) degrades GSNO, thereby regulating indirectly signaling cascades associated with this PTM. Here, the two GSNORs of the legume Lotus japonicus, LjGSNOR1 and LjGSNOR2, have been functionally characterized. The LjGSNOR1 gene is very active in leaves and roots, whereas LjGSNOR2 is highly expressed in nodules. The enzyme activities are regulated in vitro by redox-based PTMs. Reducing conditions and hydrogen sulfide-mediated cysteine persulfidation induced both activities, whereas cysteine oxidation or glutathionylation inhibited them. Ljgsnor1 knockout mutants contained higher levels of S-nitrosothiols. Affinity chromatography and subsequent shotgun proteomics allowed us to identify 19 proteins that are differentially S-nitrosylated in the mutant and the wild-type. These include proteins involved in biotic stress, protein degradation, antioxidant protection and photosynthesis. We propose that, in the mutant plants, deregulated protein S-nitrosylation contributes to developmental alterations, such as growth inhibition, impaired nodulation and delayed flowering and fruiting. Our results highlight the importance of GSNOR function in legume biology.
Topics: Aldehyde Oxidoreductases; Cysteine; Genes, Plant; Lotus; Nitric Oxide; Nitric Oxide Donors; Oxidation-Reduction; Plant Proteins; Protein Processing, Post-Translational; Protein S; Proteomics; S-Nitrosoglutathione; S-Nitrosothiols; Tandem Mass Spectrometry
PubMed: 31529085
DOI: 10.1093/pcp/pcz182 -
Thrombosis Research Mar 2023COVID-19 is associated with an increased thromboembolic risk. However, the mechanisms triggering clot formation in those patients remain unknown.
INTRODUCTION
COVID-19 is associated with an increased thromboembolic risk. However, the mechanisms triggering clot formation in those patients remain unknown.
PATIENTS AND METHODS
In 118 adult Caucasian severe but non-critically ill COVID-19 patients (median age 58 years; 73 % men) and 46 controls, we analyzed in vitro plasma thrombin generation profile (calibrated automated thrombogram [CAT assay]) and investigated thrombophilia-related factors, such as protein C and antithrombin activity, free protein S level, presence of antiphospholipid antibodies and factor V Leiden R506Q and prothrombin G20210A mutations. We also measured circulating von Willebrand factor (vWF) antigen and a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13) antigen and activity. In patients, blood samples were collected on admission to the hospital before starting any therapy, including heparin. Finally, we examined the relationship between observed alterations and disease follow-up, such as thromboembolic complications.
RESULTS
COVID-19 patients showed 17 % lower protein C activity, 22 % decreased free protein S levels, and a higher prevalence of positive results for IgM anticardiolipin antibodies. They also had 151 % increased vWF, and 27 % decreased ADAMTS13 antigens compared with controls (p < 0.001, all). On the contrary, thrombin generation potential was similar to controls. In the follow-up, pulmonary embolism (PE) occurred in thirteen (11 %) patients. They were characterized by a 55 % elevated D-dimer (p = 0.04) and 2.7-fold higher troponin I (p = 0.002) during hospitalization and 29 % shorter time to thrombin peak in CAT assay (p = 0.009) compared to patients without PE.
CONCLUSIONS
In COVID-19, we documented prothrombotic abnormalities of peripheral blood. PE was characterized by more dynamic thrombin generation growth in CAT assay performed on admittance to the hospital.
Topics: Humans; ADAMTS13 Protein; COVID-19; Protein C; Thrombin; von Willebrand Factor; Protein S
PubMed: 36709678
DOI: 10.1016/j.thromres.2023.01.016 -
Pediatrics and Neonatology Oct 2017Regular blood transfusion and compliance with iron chelation therapy has markedly improved life expectancy in thalassemia; however, this improvement is accompanied by...
BACKGROUND
Regular blood transfusion and compliance with iron chelation therapy has markedly improved life expectancy in thalassemia; however, this improvement is accompanied by several complications of this chronic disease including thromboembolic disorders. The objective of this work is to study natural coagulation inhibition as well as the fibrinolysis processes in thalassemic children who are otherwise in a steady state with no overt clinical manifestations of thromboembolism.
METHODS
In a case-control study design conducted at Sohag University Hospital, Sohag, Egypt, 50 thalassemic children and 20 age- and sex-matched healthy controls were compared as regards prothrombin concentration, international normalized ratio, partial thromboplastin time, protein C, protein S, antithrombin III, D-dimers, and thrombin activatable fibrinolysis inhibitor (TAFI).
RESULTS
When compared to healthy controls, natural coagulation inhibitors (protein C, protein S, and antithrombin-III) were significantly lower in thalassemic children (p < 0.0001). While D-dimers showed a significant increase in thalassemic children, TAFI was significantly lower (p < 0.0001). Splenectomized thalassemic children showed significantly lower levels of protein C, protein S and TAFI (p < 0.001, p < 0.0001, p < 0.0001, respectively) when compared to nonsplenectomized thalassemic children.
CONCLUSION
Significant changes in natural coagulation inhibition and fibrinolysis processes favoring thromboembolism can be detected in otherwise healthy thalassemic children. Because these changes are more pronounced in splenectomized patients, study of primary prophylactic strategies in this subgroup is warranted.
Topics: Adolescent; Blood Coagulation Disorders; Blood Proteins; Case-Control Studies; Child; Child, Preschool; Female; Fibrin Fibrinogen Degradation Products; Humans; Infant; Male; Protein S; beta-Thalassemia
PubMed: 28351558
DOI: 10.1016/j.pedneo.2016.07.009 -
Associations between pre-eclampsia and protein C and protein S levels among pregnant Nigerian women.International Journal of Gynaecology... Apr 2017To evaluate levels of protein C and free protein S among women with pre-eclampsia, and determine whether there is a relationship between deficiencies and pre-eclampsia.
OBJECTIVE
To evaluate levels of protein C and free protein S among women with pre-eclampsia, and determine whether there is a relationship between deficiencies and pre-eclampsia.
METHODS
A cross-sectional study was conducted at a hospital in Nigeria from July 2013 to March 2014 among 90 pregnant women with pre-eclampsia (blood pressure ≥140/90 mm Hg, proteinuria ≥300 mg in 24 hours) and 90 normotensive pregnant women (control group). Plasma levels of protein C and free protein S were analyzed by enzyme-linked immunosorbent assay, and protein C activity by a chromogenic method.
RESULTS
Mean protein C antigen and activity levels did not differ between groups (P=0.639 and P=0.444, respectively). The incidence of protein C antigen and activity deficiency also did not differ (P=0.288 and P>0.99, respectively). The mean free protein S antigen level was higher among women with pre-eclampsia (54.48%±19.58%) than in the control group (47.23%±10.27%; P=0.004). No woman in the control group had protein S deficiency, as compared with 2 (2%) of the women with pre-eclampsia (P=0.497). No association was found between deficiencies of these proteins and pre-eclampsia.
CONCLUSION
Deficiencies of protein C and free protein S are unlikely to be etiopathogenetic for pre-eclampsia; therefore, therapeutic intervention should focus on other potential pathogenetic pathways.
Topics: Adult; Case-Control Studies; Cross-Sectional Studies; Enzyme-Linked Immunosorbent Assay; Female; Humans; Nigeria; Pre-Eclampsia; Pregnancy; Protein C; Protein S; Risk Factors; Surveys and Questionnaires
PubMed: 28092096
DOI: 10.1002/ijgo.12085 -
Diabetes Jul 2016Protein S is an anticoagulant factor that also regulates inflammation and cell apoptosis. The effect of protein S on diabetes and its complications is unknown. This...
Protein S is an anticoagulant factor that also regulates inflammation and cell apoptosis. The effect of protein S on diabetes and its complications is unknown. This study compared the development of diabetes between wild-type and transgenic mice overexpressing human protein S and the development of diabetic glomerulosclerosis between mice treated with and without human protein S and between wild-type and protein S transgenic mice. Mice overexpressing protein S showed significant improvements in blood glucose level, glucose tolerance, insulin sensitivity, and insulin secretion compared with wild-type counterparts. Exogenous protein S improved insulin sensitivity in adipocytes, skeletal muscle, and liver cell lines in db/db mice compared with controls. Significant inhibition of apoptosis with increased expression of BIRC3 and Bcl-2 and enhanced activation of Akt/PKB was induced by protein S in islet β-cells compared with controls. Diabetic wild-type mice treated with protein S and diabetic protein S transgenic mice developed significantly less severe diabetic glomerulosclerosis than controls. Patients with type 2 diabetes had significantly lower circulating free protein S than healthy control subjects. This study shows that protein S attenuates diabetes by inhibiting apoptosis of β-cells and the development of diabetic nephropathy.
Topics: Adipocytes; Animals; Apoptosis; Blood Glucose; Cell Line; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Female; Glucose Tolerance Test; Humans; Insulin Resistance; Insulin-Secreting Cells; Liver; Male; Mice; Mice, Transgenic; Middle Aged; Muscle, Skeletal; Protein S
PubMed: 27207541
DOI: 10.2337/db15-1404 -
Rinsho Byori. the Japanese Journal of... Dec 2015During normal pregnancy, the pro-coagulant activity is increased, while the anticoagulant activity is reduced, resulting in a prothrombotic environment that predisposes... (Review)
Review
During normal pregnancy, the pro-coagulant activity is increased, while the anticoagulant activity is reduced, resulting in a prothrombotic environment that predisposes toward venous thromboembolism (VTE). VTE occurs frequently in pregnant women and is a leading cause of maternal morbidity and mortality. Hemostatic abnormalities were examined in 14 pregnant women with deep vein thrombosis (DVT). We studied five families with congenital antithrombin (AT) deficiency and two families with congenital protein C (PC) deficiency. One woman with PC deficiency showed protein S (PS) Tokushima. The AT activity levels were significantly lower at the onset of DVT in the pregnant women than during the stable state. The PS activity and antigen levels were also significantly lower at the onset of DVT. In the patients with congenital AT deficiency, AT activity was significantly lower in the stable state and decreased further at the onset of DVT. Although AT levels were normal before pregnancy, they subsequently decreased and in two cases the patients required the administration of AT after pregnancy. Gene analysis revealed one family with AT Budapest, one family with AT Toyama, and three families with AT Glasgow. Additionally, there was one family with PC Tochigi and one family with combined heterozygous PC deficiency and PS Tokushima. In conclusion, the deficiency of natural anticoagulants, especially AT, is an important cause of pregnancy-related VTE.
Topics: Anticoagulants; Antithrombin III Deficiency; Female; Genetic Testing; Humans; Pregnancy; Protein S; Risk Factors; Venous Thromboembolism
PubMed: 27089659
DOI: No ID Found -
The Journal of Physical Chemistry. B Apr 2018S-aromatic motifs are important noncovalent forces for protein stability and function but remain poorly understood. Hence, we performed quantum calculations at the...
S-aromatic motifs are important noncovalent forces for protein stability and function but remain poorly understood. Hence, we performed quantum calculations at the MP2(full)/6-311++G(d,p) level on complexes between Cys (HS, MeSH) and Met (MeS) models with models of Phe (benzene, toluene), Trp (indole, 3-methylindole), Tyr (phenol, 4-methylphenol), and His (imidazole, 4-methylimidazole). The most stable gas-phase conformers exhibit binding energies of -2 to -6 kcal/mol, and the S atom lies perpendicular to the ring plane. This reveals preferential interaction with the ring π-system, except in the imidazoles where S binds edge-on to an N atom. Complexation tunes the gas-phase vertical ionization potentials of the ligands over as much as 1 eV, and strong σ- or π-type H-bonding supports charge transfer to the H-bond donor, rendering it more oxidizable. When the S atom acts as an H-bond acceptor (N/O-H···S), calibration of the CHARMM36 force field (by optimizing pair-specific Lennard-Jones parameters) is required. Implementing the optimized parameters in molecular dynamics simulations in bulk water, we find stable S-aromatic complexes with binding free energies of -0.6 to -1.1 kcal/mol at ligand separations up to 8 Å. The aqueous S-aromatics exhibit flexible binding conformations, but edge-on conformers are less stable in water. Reflecting this, only 0.3 to 10% of the S-indole, S-phenol, and S-imidazole structures are stabilized by N/O-H···S or S-H···O/N σ-type H-bonding. The wide range of energies and geometries found for S-aromatic interactions and their tunable redox properties expose the versatility and variability of the S-aromatic motif in proteins and allow us to predict a number of their reported properties.
Topics: Molecular Dynamics Simulation; Oxidation-Reduction; Protein Conformation; Protein S; Quantum Theory
PubMed: 29533644
DOI: 10.1021/acs.jpcb.8b00089 -
Journal of Agricultural and Food... Feb 2022The objective of the present study was to investigate the regulatory mechanism of protein S-nitrosylation on early postmortem beef muscle apoptosis. Beef semimembranosus...
The objective of the present study was to investigate the regulatory mechanism of protein S-nitrosylation on early postmortem beef muscle apoptosis. Beef semimembranosus (SM) muscles at 45 min postmortem were treated with nitric oxide (NO) donor, control (NaCl solution), or nitric oxide synthase (NOS) inhibitor for 24 h at 4 °C. Bcl-2 expression and mitochondrial membrane potential were significantly increased by the NO donor treatment at 6 h postmortem, while the NOS inhibitor group exhibited a lower Bcl-2 level and mitochondrial membrane potential in comparison with the control ( < 0.05). The cytochrome c expression analysis highlighted that NO donor incubation repressed cytochrome c release from mitochondria to the cytoplasm. Further, S-nitrosylation levels of caspase-3 and caspase-9 were elevated after incubation with the NO donor ( < 0.05), leading to decreased caspase-3 and caspase-9 activities ( < 0.05). The aforementioned findings imply that protein S-nitrosylation mediates postmortem apoptosis of beef SM through the mitochondrial apoptotic pathway.
Topics: Animals; Apoptosis; Caspase 3; Cattle; Cytochromes c; Mitochondria; Nitric Oxide; Protein S
PubMed: 34968404
DOI: 10.1021/acs.jafc.1c06516 -
Food Chemistry Dec 2016The effect of S-nitrosylation on the autolysis and catalytic ability of μ-calpain in vitro in the presence of 50μM Ca(2 +) was investigated. μ-Calpain was incubated...
The effect of S-nitrosylation on the autolysis and catalytic ability of μ-calpain in vitro in the presence of 50μM Ca(2 +) was investigated. μ-Calpain was incubated with different concentrations of nitric oxide donor S-nitrosoglutathione (GSNO) and subsequently reacted with purified myofibrils. Results showed that the amount of 80kDa μ-calpain subunit significantly decreased as GSNO increased from 0 to 300μM, but increases of GSNO to 300, 500 and 1000μM did not result in further inhibition. The catalytic ability of nitrosylated μ-calpain to degrade titin, nebulin, troponin-T and desmin was significantly reduced when the GSNO concentration was higher than 300μM. The cysteine residues of μ-calpain at positions 49, 351, 384, and 592 in the catalytic subunit and at 142 in small subunit were S-nitrosylated, which could be responsible for decreased μ-calpain activity. Thus, S-nitrosylation can negatively regulate the activation of μ-calpain resulting in decreased proteolytic ability on myofibrils.
Topics: Amino Acid Sequence; Animals; Autolysis; Calpain; Catalysis; Desmin; Muscle Proteins; Myofibrils; Protein S; Proteolysis; Swine; Troponin T
PubMed: 27451206
DOI: 10.1016/j.foodchem.2016.06.104