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1.
Clin Immunol ; 261: 109926, 2024 04.
Artigo em Inglês | MEDLINE | ID: mdl-38355030

RESUMO

Our study aimed to evaluate the presence, clinical associations, and potential mechanistic roles of non-criteria antiphospholipid antibodies (aPL) and circulating calprotectin, a highly stable marker of neutrophil extracellular trap release (NETosis), in pediatric APS patients. We found that 79% of pediatric APS patients had at least one non-criteria aPL at moderate-to-high titer. Univariate logistic regression demonstrated that positive anti-beta-2 glycoprotein I domain 1 (anti-D1) IgG (p = 0.008), anti-phosphatidylserine/prothrombin (aPS/PT) IgG (p < 0.001), and aPS/PT IgM (p < 0.001) were significantly associated with venous thrombosis. Positive anti-D1 IgG (p < 0.001), aPS/PT IgG (p < 0.001), and aPS/PT IgM (p = 0.001) were also associated with non-thrombotic manifestations of APS, such as thrombocytopenia. Increased levels of calprotectin were detected in children with APS. Calprotectin correlated positively with absolute neutrophil count (r = 0.63, p = 0.008) and negatively with platelet count (r = -0.59, p = 0.015). Mechanistically, plasma from pediatric APS patients with high calprotectin levels impaired platelet viability in a dose-dependent manner.


Assuntos
Anticorpos Antifosfolipídeos , Síndrome Antifosfolipídica , Humanos , Criança , Biomarcadores , beta 2-Glicoproteína I , Imunoglobulina G , Imunoglobulina M , Protrombina , Complexo Antígeno L1 Leucocitário
2.
Blood ; 143(12): 1193-1197, 2024 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-38237140

RESUMO

ABSTRACT: Many patients with antiphospholipid syndrome had decreased ectonucleotidase activity on neutrophils and platelets, which enabled extracellular nucleotides to trigger neutrophil-platelet aggregates. This phenotype was replicated by treating healthy neutrophils and platelets with patient-derived antiphospholipid antibodies or ectonucleotidase inhibitors.


Assuntos
Síndrome Antifosfolipídica , Humanos , Neutrófilos , Anticorpos Antifosfolipídeos , Plaquetas
3.
Arthritis Rheumatol ; 2024 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-38225923

RESUMO

OBJECTIVE: While thrombosis and pregnancy loss are the best-known clinical features of antiphospholipid syndrome (APS), many patients also exhibit "extra-criteria" manifestations, such as thrombocytopenia. The mechanisms that drive APS thrombocytopenia are not completely understood, and no clinical biomarkers are available for predicting antiphospholipid antibody (aPL)-mediated thrombocytopenia. Calprotectin is a heterodimer of S100A8 and S100A9 that is abundant in the neutrophil cytoplasm and released upon proinflammatory neutrophil activation. Here, we sought to evaluate the presence, clinical associations, and potential mechanistic roles of circulating calprotectin in a cohort of primary APS and aPL-positive patients. METHODS: Levels of circulating calprotectin were determined in plasma by the QUANTA Flash chemiluminescent assay. A viability dye-based platelet assay was used to assess the potential impact of calprotectin on aPL-mediated thrombocytopenia. RESULTS: Circulating calprotectin was measured in 112 patients with primary APS and 30 aPL-positive (without APS criteria manifestations or lupus) patients as compared to patients with lupus (without APS), patients with unprovoked venous thrombosis (without aPL), and healthy controls. Levels of calprotectin were higher in patients with primary APS and aPL-positive patients compared to healthy controls. After adjustment for age and sex, calprotectin level correlated positively with absolute neutrophil count (r = 0.41, P < 0.001), positively with C-reactive protein level (r = 0.34, P = 0.002), and negatively with platelet count (r = -0.24, P = 0.004). Mechanistically, we found that calprotectin provoked aPL-mediated thrombocytopenia by engaging platelet surface toll-like receptor 4 and activating the NLRP3-inflammasome, thereby reducing platelet viability in a caspase-1-dependent manner. CONCLUSION: These data suggest that calprotectin has the potential to be a functional biomarker and a new therapeutic target for APS thrombocytopenia.

4.
Sci Adv ; 9(43): eadj1019, 2023 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-37878711

RESUMO

While neutrophil extracellular traps (NETs) have previously been linked to some diabetes-associated complications, such as dysfunctional wound healing, their potential role in diabetic vascular dysfunction has not been studied. Diabetic Akita mice were crossed with either Elane-/- or Pad4-/- mice to generate NET-deficient diabetic mice. By 24 weeks of age, Akita aortae showed markedly impaired relaxation in response to acetylcholine, indicative of vascular dysfunction. Both Akita-Elane-/- mice and Akita-Pad4-/- mice had reduced levels of circulating NETs and improved acetylcholine-mediated aortic relaxation. Compared with wild-type aortae, the thromboxane metabolite TXB2 was roughly 10-fold higher in both intact and endothelium-denuded aortae of Akita mice. In contrast, Akita-Elane-/- and Akita-Pad4-/- aortae had TXB2 levels similar to wild type. In summary, inhibition of NETosis by two independent strategies prevented the development of vascular dysfunction in diabetic Akita mice. Thromboxane was up-regulated in the vessel walls of NETosis-competent diabetic mice, suggesting a role for neutrophils in driving the production of this vasoconstrictive and atherogenic prostanoid.


Assuntos
Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 1 , Armadilhas Extracelulares , Camundongos , Animais , Armadilhas Extracelulares/metabolismo , Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 1/metabolismo , Acetilcolina , Neutrófilos/metabolismo , Tromboxanos/metabolismo
5.
Biochim Biophys Acta Mol Basis Dis ; 1869(5): 166688, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36925054

RESUMO

Cell-free heme (CFH) is a product of hemoglobin, myoglobin and hemoprotein degradation, which is a hallmark of pathologies associated with extensive hemolysis and tissue damage. CHF and iron collectively induce cytokine storm, lung injury, respiratory distress and infection susceptibility in the lungs suggesting their key role in the progression of lung disease pathology. We have previously demonstrated that heme-mediated reactive oxygen species (ROS) induces platelet activation and ferroptosis. However, interaction of ferroptotic platelets and neutrophils, the mechanism of action and associated complications remain unclear. In this study, we demonstrate that heme-induced P-selectin expression and Phosphatidylserine (PS) externalization in platelets via ASK-1-inflammasome axis increases platelet-neutrophil aggregates in circulation, resulting in Neutrophil extracellular traps (NET) formation in vitro and in vivo. Further, heme-induced platelet activation in mice increased platelet-neutrophil aggregates and accumulation of NETs in the lungs causing pulmonary damage. Thus, connecting CFH-mediated platelet activation to NETosis and pulmonary thrombosis. As lung infections induce acute respiratory stress, thrombosis and NETosis, we propose that heme -mediated platelet activation and ferroptosis might be crucial in such clinical manifestations. Further, considering the ability of redox modulators and ferroptosis inhibitors like FS-1, Lpx-1 and DFO to inhibit heme-induced ferroptotic platelets-mediated NETosis and pulmonary thrombosis. They could be potential adjuvant therapy to regulate respiratory distress-associated clinical complications.


Assuntos
Ferroptose , Pneumopatias , Síndrome do Desconforto Respiratório , Trombose , Camundongos , Animais , Heme , Ativação Plaquetária , Pulmão/patologia , Trombose/patologia
7.
Angew Chem Int Ed Engl ; 60(6): 3121-3130, 2021 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-33079465

RESUMO

Nanoparticles that functionally mimic the activity of metal-containing enzymes (metallo-nanozymes) are of therapeutic importance for treating various diseases. However, it is still not clear whether such nanozymes can completely substitute the function of natural enzymes in living cells. In this work, we show for the first time that a cerium vanadate (CeVO4 ) nanozyme can substitute the function of superoxide dismutase 1 and 2 (SOD1 and SOD2) in the neuronal cells even when the natural enzyme is down-regulated by specific gene silencing. The nanozyme prevents the mitochondrial damage in SOD1- and SOD2-depleted cells by regulating the superoxide levels and restores the physiological levels of the anti-apoptotic Bcl-2 family proteins. Furthermore, the nanozyme effectively prevents the mitochondrial depolarization, leading to a significant improvement in the cellular levels of ATP under oxidative stress.


Assuntos
Trifosfato de Adenosina/metabolismo , Cério/química , Mitocôndrias/metabolismo , Nanoestruturas/química , Vanadatos/química , Materiais Biomiméticos/química , Materiais Biomiméticos/metabolismo , Linhagem Celular Tumoral , Humanos , Neurônios/citologia , Neurônios/metabolismo , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Superóxido Dismutase/antagonistas & inibidores , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo , Superóxido Dismutase-1/antagonistas & inibidores , Superóxido Dismutase-1/genética , Superóxido Dismutase-1/metabolismo , Superóxidos/metabolismo
8.
ACS Chem Biol ; 15(10): 2673-2682, 2020 10 16.
Artigo em Inglês | MEDLINE | ID: mdl-32915529

RESUMO

Red blood cell death or erythrocyte apoptosis (eryptosis) is generally mediated by oxidative stress, energy depletion, heavy metals exposure, or xenobiotics. As erythrocytes are a major target for oxidative stress due to their primary function as O2-carrying cells, they possess an efficient antioxidant defense system consisting of glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), and peroxiredoxin 2 (Prx2). The oxidative stress-mediated activation of the Ca2+-permeable cation channel results in Ca2+ entry into the cells and subsequent cell death. Herein, we describe for the first time that selenium compounds having intramolecular diselenide or selenenyl sulfide moieties can prevent the oxidative stress-induced eryptosis by exhibiting an unusual Prx2-like redox activity under conditions when the cellular Prx2 and CAT enzymes are inhibited.


Assuntos
Antioxidantes/farmacologia , Eriptose/efeitos dos fármacos , Eritrócitos/efeitos dos fármacos , Homeostase/efeitos dos fármacos , Compostos Organosselênicos/farmacologia , Transdução de Sinais/efeitos dos fármacos , Humanos , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Peroxirredoxinas/química , Tiorredoxinas/metabolismo
9.
J Pineal Res ; 69(3): e12676, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32597503

RESUMO

Melatonin is a chronobiotic hormone, which can regulate human diseases like cancer, atherosclerosis, respiratory disorders, and microbial infections by regulating redox system. Melatonin exhibits innate immunomodulation by communicating with immune system and influencing neutrophils to fight infections and inflammation. However, sustaining redox homeostasis and reactive oxygen species (ROS) generation in neutrophils are critical during chemotaxis, oxidative burst, phagocytosis, and neutrophil extracellular trap (NET) formation. Therefore, endogenous antioxidant glutathione (GSH) redox cycle is highly vital in regulating neutrophil functions. Reduced intracellular GSH levels and glutathione reductase (GR) activity in the neutrophils during clinical conditions like autoimmune disorders, neurological disorders, diabetes, and microbial infections lead to dysfunctional neutrophils. Therefore, we hypothesized that redox modulators like melatonin can protect neutrophil health and functions under GSH and GR activity-deficient conditions. We demonstrate the dual role of melatonin, wherein it protects neutrophils from oxidative stress-induced apoptosis by reducing ROS generation; in contrast, it restores neutrophil functions like phagocytosis, degranulation, and NETosis in GSH and GR activity-deficient neutrophils by regulating ROS levels both in vitro and in vivo. Melatonin mitigates LPS-induced neutrophil dysfunctions by rejuvenating GSH redox system, specifically GR activity by acting as a parallel redox system. Our results indicate that melatonin could be a potential auxiliary therapy to treat immune dysfunction and microbial infections, including virus, under chronic disease conditions by restoring neutrophil functions. Further, melatonin could be a promising immune system booster to fight unprecedented pandemics like the current COVID-19. However, further studies are indispensable to address the clinical usage of melatonin.


Assuntos
Antioxidantes/uso terapêutico , Glutationa/metabolismo , Melatonina/uso terapêutico , Neutrófilos/efeitos dos fármacos , Animais , Antioxidantes/farmacologia , Apoptose/efeitos dos fármacos , Infecções por Coronavirus/tratamento farmacológico , Avaliação Pré-Clínica de Medicamentos , Feminino , Glutationa Redutase/metabolismo , Humanos , Masculino , Melatonina/farmacologia , Camundongos , Mitocôndrias/metabolismo , NADPH Oxidases/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Tratamento Farmacológico da COVID-19
10.
Biochim Biophys Acta Gen Subj ; 1864(6): 129561, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32068016

RESUMO

BACKGROUND: Neutrophils are the first line defense cells of the innate immunity. As a final defense, they discharge their de-condensed chromatin/DNA fibers, the NETs (Neutrophil Extracellular Traps), by a process called NETosis. Two types of NETosis have been currently described: the suicidal/delayed/classical-type, which is ROS dependent that results in the ejection of nuclear DNA, and the vital/rapid/early-type, which may or may not require ROS but, eject nuclear/mitochondrial DNA or both. Thus, Echis carinatus and Naja naja venoms are comparatively studied for their NET inducing property. METHODS: Formation of NETs, cell viability, ROS, and Ca2+ levels are estimated. An in vivo toxicity study and possible cellular signaling have been addressed using immunoblots and pharmacological inhibitors. RESULTS: E. carinatus and N. naja venoms respectively induce suicidal and vital NETosis. E. carinatus venom induces NETosis by activating NOX and PAD-4 enzymes in a ROS dependent manner via PKC/ERK/JNK signaling axis, while N. naja venom does it by activating PAD-4 enzyme, but independent of ROS requirement and as well as PKC/ERK/JNK activation. CONCLUSION: For the first time our study demonstrates the distinct action of E. carinatus and N. naja venoms on the process of NETosis. NETosis being a newly explored area in snake venom pharmacodynamics, it is important to study its impact on the various pathophysiological properties induced by snake venoms. SIGNIFICANCE: Understanding the varied actions of snake venoms on neutrophils/blood cells and the role of DNase are likely to provide insights for better management of snakebite pathophysiology.


Assuntos
Venenos Elapídicos/farmacologia , Neutrófilos/efeitos dos fármacos , Mordeduras de Serpentes/metabolismo , Venenos de Víboras/farmacologia , Animais , Venenos Elapídicos/química , Humanos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/genética , Naja naja/metabolismo , Neutrófilos/patologia , Mordeduras de Serpentes/patologia , Venenos de Víboras/química
11.
Biochim Biophys Acta Mol Basis Dis ; 1865(9): 2303-2316, 2019 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-31102787

RESUMO

Reactive oxygen species (ROS) are capable of inducing cell death or apoptosis. Recently, we demonstrated that lipid-ROS can mediate ferroptosis and activation of human platelets. Ferroptosis is an intracellular iron-mediated cell death, distinct from classical apoptosis and necrosis, which is mediated through the accumulation of ROS, lipid peroxides and depletion of cellular GSH. Lately, we demonstrated that hemoglobin degradation product hemin induces ferroptosis in platelets via ROS and lipid peroxidation. In this study, we demonstrate that hemin-induced ferroptosis in platelets is mediated through ROS-driven proteasome activity and inflammasome activation, which were mitigated by Melatonin (MLT). Although inflammasome activation is linked with pyroptosis, it is still not clear whether ferroptosis is associated with inflammasome activation. Our study for the first time demonstrates an association of platelet activation/ferroptosis with proteasome activity and inflammasome activation. Although, high-throughput screening has recognized ferrostatin-1 (Fer-1) and liproxstatin-1 (Lip-1) as potent ferroptosis inhibitors, having an endogenous antioxidant such as MLT as ferroptosis inhibitor is of high interest. MLT is a well-known chronobiotic hormone that regulates the circadian rhythms in vertebrates. It also exhibits potent antioxidant and ROS quenching capabilities. MLT can regulate fundamental cellular functions by exhibiting cytoprotective, oncostatic, antiaging, anti-venom, and immunomodulatory activities. The ROS scavenging capacity of MLT is key for its cytoprotective and anti-apoptotic properties. Considering the anti-ferroptotic and anti-apoptotic potentials of MLT, it could be a promising clinical application to treat hemolytic, thrombotic and thrombocytopenic conditions. Therefore, we propose MLT as a pharmacological and therapeutic agent to inhibit ferroptosis and platelet activation.


Assuntos
Ferroptose/efeitos dos fármacos , Hemina/farmacologia , Inflamassomos/metabolismo , Melatonina/farmacologia , Ativação Plaquetária/efeitos dos fármacos , Complexo de Endopeptidases do Proteassoma/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Animais , Plaquetas/citologia , Plaquetas/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Citocinas/sangue , Glutationa/metabolismo , Humanos , Masculino , Camundongos , Estresse Oxidativo/efeitos dos fármacos , Selectina-P/sangue , Complexo de Endopeptidases do Proteassoma/química , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo
12.
Environ Toxicol ; 34(3): 262-270, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30461186

RESUMO

The catecholic derivative para-tertiary butyl catechol (PTBC) is a conventional antioxidant and polymerization inhibitor, which exhibits melanocytotoxic effects and contact dermatitis often leading to occupational leucoderma or vitiligo. Although numerous industrial workers will be in constant exposure to PTBC and its chances of getting entry into blood are most expected, its effect on blood components is still undisclosed. As platelets play a prominent role in dermatitis, inflammation, and immunity, in this study we have evaluated the effect of PTBC on human platelets in vitro. Exposure of platelets to PTBC showed increased reactive oxygen species (ROS), intracellular calcium, cardiolipin oxidation, mitochondrial permeability transition pore (MPTP) formation, activation of caspases, phosphatidylserine (PS) externalization and decreased mitochondrial membrane potential. In addition, there was a significant decrease in cellular glutathione level, increased γ-glutamyltransferase (GGT) activity and cell death. These findings demonstrate that PTBC could induce toxic effects on blood components, which is often ignored field of research. Since dermal exposure of humans to toxic chemicals covers an important issue in various industries, there is a need of such work to understand and update the long-term toxicities induced by PTBC usage in industrial sectors and public domain.


Assuntos
Antioxidantes/toxicidade , Plaquetas/citologia , Butanos/toxicidade , Apoptose/efeitos dos fármacos , Plaquetas/efeitos dos fármacos , Plaquetas/metabolismo , Caspases/metabolismo , Glutationa/metabolismo , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Poro de Transição de Permeabilidade Mitocondrial , Fosfatidilserinas/metabolismo , Espécies Reativas de Oxigênio/metabolismo
13.
ACS Chem Biol ; 13(8): 1996-2002, 2018 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-29869870

RESUMO

Hemolysis, a process by which the destruction of red blood cells leads to the release of hemoglobin, is a critical event observed during hemolytic disorders. Under oxidative stress conditions, hemoglobin can release its heme prosthetic group, which is highly cytotoxic and can catalyze the generation of reactive oxygen species (ROS), leading to several undesired redox reactions in the cells. Herein, we demonstrate for the first time that heme can mediate the activation and death of human platelets through ferroptosis, which is an iron-dependent form of nonapoptotic cell death. This study also suggests that the heme-mediated lipid peroxidation and ferroptosis in platelets may play an important role in hemolytic disorders.


Assuntos
Plaquetas/metabolismo , Morte Celular/efeitos dos fármacos , Hemina/metabolismo , Radical Hidroxila/metabolismo , Ativação Plaquetária/efeitos dos fármacos , Cicloexilaminas/farmacologia , Heme Oxigenase-1/metabolismo , Humanos , Peroxidação de Lipídeos/efeitos dos fármacos , Fenilenodiaminas/farmacologia
14.
Biochim Biophys Acta Gen Subj ; 1862(5): 1115-1125, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29425807

RESUMO

BACKGROUND: E. carinatus bite is a serious threat to South-Asian countries including India, as it causes the highest number of deaths and debilitating sustained tissue necrosis at the bite site. One of our previous studies has demonstrated the strong interaction between DNA and E. carinatus venom. Therefore, in this study, the effect of DNA on E. carinatus venom has been examined. METHODS: Here we show that calf thymus DNA interact strongly with E. carinatus venom and inhibits its enzymatic and pharmacological activities such as proteolytic, hemolytic, hyaluronidase, L-amino acid oxidase, NETosis, hemorrhage, pro-coagulant, and lethality. Further, using immunoblots and immunofluorescence, the study demonstrates the inhibition of proteolytic cleavage of several surface receptors on PMNs, PBMCs, and platelets by the DNA. CONCLUSIONS: This study for the first time explored the efficient inhibition of enzymatic, pharmacological and lethal properties of E. carinatus venom by the naked DNA and demonstrates the possible therapeutic application of it during snakebite management. GENERAL SIGNIFICANCE: This study identifies naked DNA as an effective defense weapon that has got the therapeutic potential to inhibit the detrimental effects of E. carinatus bite.


Assuntos
DNA , Mordeduras de Serpentes , Venenos de Víboras , Viperidae , Animais , Bovinos , DNA/química , DNA/farmacologia , Feminino , Humanos , Masculino , Camundongos , Mordeduras de Serpentes/tratamento farmacológico , Mordeduras de Serpentes/metabolismo , Venenos de Víboras/antagonistas & inibidores , Venenos de Víboras/química , Venenos de Víboras/toxicidade
15.
Toxicol Appl Pharmacol ; 334: 167-179, 2017 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-28911973

RESUMO

Chronic hyperglycemia is one of the characteristic conditions associated with Diabetes Mellitus (DM), which often exerts deleterious effects on erythrocyte morphology and hemodynamic properties leading to anemia and diabetes-associated vascular complications. High glucose-induced over production of reactive oxygen species (ROS) can alter the blood cell metabolism and biochemical functions subsequently causing eryptosis (red blood cell death), yet another complication of concern in DM. Therefore, blocking high glucose-induced oxidative damage and subsequent eryptosis is of high importance in the better management of DM and associated vascular complications. In this study, we synthesized an oxolane derivative 1-(2,2-dimethyltetrahydrofuro[2,3][1,3]dioxol-5-yl)ethane-1,2-diol (DMTD), and demonstrated its efficacy to mitigate hyperglycemia-induced ROS generation and subsequent eryptosis. We showed that DMTD effectively inhibits high glucose-induced ROS generation, intracellular calcium levels, phosphaditylserine (PS) scrambling, calpain and band 3 activation, LDH leakage, protein glycation and lipid peroxidation, meanwhile enhances the antioxidant indices, osmotic fragility and Na+/K+-ATPase activity in erythrocytes. DMTD dose dependently decreased the glycated hemoglobin level and enhances the glucose utilization by erythrocytes in vitro. Further, DMTD alleviated the increase in ROS production, intracellular Ca2+ level and PS externalization in the erythrocytes of human diabetic subjects and enhanced the Na+/K+-ATPase activity. Taken together, the synthesized oxolane derivative DMTD could be a novel synthetic inhibitor of high glucose-induced oxidative stress and eryptosis. Considering the present results DMTD could be a potential therapeutic to treat DM and associated complications and open new avenues in developing synthetic therapeutic targeting of DM-associated complications.


Assuntos
Diabetes Mellitus/sangue , Membrana Eritrocítica/efeitos dos fármacos , Eritrócitos/efeitos dos fármacos , Glucose/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Tiazóis/farmacologia , Animais , Apoptose/efeitos dos fármacos , Diabetes Mellitus/metabolismo , Relação Dose-Resposta a Droga , Glucose/administração & dosagem , Humanos , Peroxidação de Lipídeos , Camundongos , Estrutura Molecular , ATPase Trocadora de Sódio-Potássio/metabolismo , Tiazóis/administração & dosagem , Tiazóis/química
16.
Biochem Biophys Res Commun ; 491(1): 183-191, 2017 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-28712866

RESUMO

Cell-free hemoglobin (Hb), a well-known marker of intravascular hemolysis, is eventually oxidized to methemoglobin (MtHb). Elevated levels of MtHb have been noted, alongside depleted levels of platelets, in several hemolytic diseases. The current study aims to probe the possible role of MtHb in platelet death, based on the facts that it is a pro-inflammatory and pro-apoptotic agent, as well as the sensitive nature of platelets and their tendency to undergo apoptosis under oxidative stress. An attempt is made to establish the link between hemolysis and thrombocytopenia, by deciphering the underlying molecular signaling pathways. The results of this study demonstrate that MtHb, not Hb exerts oxidative stress on platelets, which triggers their death via ROS-mediated mitochondrial apoptotic pathway. It was further established that the MtHb-induced platelet apoptotic events mediate through JNK and p38 MAPK activation. Thus, the study presents a mechanistic insight into the previous studies that reported the incidence of thrombocytopenia in hemolytic diseases. This study highlights the fate of platelets in intravascular hemolytic conditions, which demands the need for a specific treatment strategy considering the risks associated with thrombocytopenia during severe hemolytic diseases.


Assuntos
Apoptose/fisiologia , Plaquetas/fisiologia , MAP Quinase Quinase 7/metabolismo , Mitocôndrias/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Apoptose/efeitos dos fármacos , Plaquetas/efeitos dos fármacos , Sistema Livre de Células/química , Células Cultivadas , Ativação Enzimática/efeitos dos fármacos , Humanos , Metemoglobina/farmacologia , Mitocôndrias/efeitos dos fármacos , Proteínas Mitocondriais/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologia
17.
Nat Commun ; 7: 11361, 2016 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-27093631

RESUMO

Indian Echis carinatus bite causes sustained tissue destruction at the bite site. Neutrophils, the major leukocytes in the early defence process, accumulate at the bite site. Here we show that E. carinatus venom induces neutrophil extracellular trap (NET) formation. The NETs block the blood vessels and entrap the venom toxins at the injection site, promoting tissue destruction. The stability of NETs is attributed to the lack of NETs-degrading DNase activity in E. carinatus venom. In a mouse tail model, mice co-injected with venom and DNase 1, and neutropenic mice injected with the venom, do not develop NETs, venom accumulation and tissue destruction at the injected site. Strikingly, venom-induced mice tail tissue destruction is also prevented by the subsequent injection of DNase 1. Thus, our study suggests that DNase 1 treatment may have a therapeutic potential for preventing the tissue destruction caused by snake venom.


Assuntos
Antídotos/farmacologia , Desoxirribonuclease I/farmacologia , Armadilhas Extracelulares/efeitos dos fármacos , Necrose/prevenção & controle , Neutropenia/imunologia , Venenos de Víboras/antagonistas & inibidores , Animais , Antídotos/metabolismo , Desoxirribonuclease I/metabolismo , Armadilhas Extracelulares/imunologia , Feminino , Injeções Intralesionais , Masculino , Camundongos , Necrose/induzido quimicamente , Necrose/patologia , Neutrófilos/citologia , Neutrófilos/imunologia , Fatores de Proteção , Cauda/efeitos dos fármacos , Cauda/imunologia , Cauda/patologia , Venenos de Víboras/administração & dosagem , Venenos de Víboras/toxicidade , Viperidae/fisiologia
18.
Mol Cell Biochem ; 414(1-2): 137-51, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26899710

RESUMO

Thrombocytopenia is a major hematological concern in oxidative stress-associated pathologies and chronic clinical disorders, where premature platelet destruction severely affects the normal functioning of thrombosis and hemostasis. In addition, frequent exposure of platelets to chemical entities and therapeutic drugs immensely contributes in the development of thrombocytopenia leading to huge platelet loss, which might be fatal sometimes. Till date, there are only few platelet protective molecules known to combat thrombocytopenia. Hence, small molecule therapeutics are extremely in need to relieve the burden on limited treatment strategies of thrombocytopenia. In this study, we have synthesized a series of novel 3,4,5 trisubstituted isoxazole derivatives, among which compound 4a [4-methoxy-N'-(5-methyl-3-phenylisoxazole-4-carbonyl) benzenesulfonohydrazide] was found to significantly ameliorate the oxidative stress-induced platelet apoptosis by restoring various apoptotic markers such as ROS content, cytosolic Ca(2+) levels, eIF2-α phosphorylation, mitochondrial membrane depolarization, cytochrome c release, caspase activation, PS externalization, and cytotoxicity markers. Additionally, compound 4a dose dependently inhibits collagen-induced platelet aggregation. Hence, compound 4a can be considered as a prospective molecule in the treatment regime of platelet activation and apoptosis and other clinical conditions of thrombocytopenia. Further studies might ensure the use of compound 4a as a supplementary therapeutic agent to treat, thrombosis and CVD-associated complications. Over all, the study reveals a platelet protective efficacy of novel isoxazole derivative 4a with a potential to combat oxidative stress-induced platelet apoptosis.


Assuntos
Apoptose/efeitos dos fármacos , Plaquetas/efeitos dos fármacos , Isoxazóis/farmacologia , Agregação Plaquetária/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Plaquetas/metabolismo , Cálcio/metabolismo , Caspases/efeitos dos fármacos , Glucosefosfato Desidrogenase/antagonistas & inibidores , Glutationa/metabolismo , Dissulfeto de Glutationa/metabolismo , Humanos , Isoxazóis/química , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , gama-Glutamiltransferase/antagonistas & inibidores
19.
Sci Rep ; 5: 15045, 2015 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-26459859

RESUMO

Thrombocytopenia is one of the most frequently observed secondary complications in many pathological conditions including liver diseases, where hyperbilirubinemia is very common. The present study sought to find the cause of thrombocytopenia in unconjugated hyperbilirubinemic conditions. Unconjugated bilirubin (UCB), an end-product of heme catabolism, is known to have pro-oxidative and cytotoxic effects at high serum concentration. We investigated the molecular mechanism underlying the pro-apoptotic effect of UCB on human platelets in vitro, and followed it up with studies in phenylhydrazine-induced hyperbilirubinemic rat model and hyperbilirubinemic human subjects. UCB is indeed found to significantly induce platelet apoptotic events including elevated endogenous reactive oxygen species generation, mitochondrial membrane depolarization, increased intracellular calcium levels, cardiolipin peroxidation and phosphatidylserine externalization (p < 0.001) as evident by FACS analysis. The immunoblots show the elevated levels of cytosolic cytochrome c and caspase activation in UCB-treated platelets. Further, UCB is found to induce mitochondrial ROS generation leading to p38 activation, followed by downstream activation of p53, ultimately resulting in altered expression of Bcl-2 and Bax proteins as evident from immunoblotting. All these parameters conclude that elevated unconjugated bilirubin causes thrombocytopenia by stimulating platelet apoptosis via mitochondrial ROS-induced p38 and p53 activation.


Assuntos
Apoptose , Bilirrubina/metabolismo , Plaquetas/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Animais , Apoptose/efeitos dos fármacos , Bilirrubina/farmacologia , Plaquetas/efeitos dos fármacos , Cálcio/metabolismo , Cardiolipinas/metabolismo , Modelos Animais de Doenças , Humanos , Hiperbilirrubinemia/metabolismo , Potencial da Membrana Mitocondrial , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Fosforilação , Ratos , Transdução de Sinais/efeitos dos fármacos , Proteína Supressora de Tumor p53/metabolismo
20.
Sci Rep ; 5: 11117, 2015 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-26059174

RESUMO

Medicinal plants are employed in the treatment of human ailments from time immemorial. Several studies have validated the use of medicinal plant products in arthritis treatment. Arthritis is a joint disorder affecting subchondral bone and cartilage. Degradation of cartilage is principally mediated by enzymes like matrix metalloproteinases (MMPs), hyaluronidases (HAase), aggrecanases and exoglycosidases. These enzymes act upon collagen, hyaluronan and aggrecan of cartilage respectively, which would in turn activate bone deteriorating enzymes like cathepsins and tartrate resistant acid phosphatases (TRAP). Besides, the incessant action of reactive oxygen species and the inflammatory mediators is reported to cause further damage by immunological activation. The present study demonstrated the anti-arthritic efficacy of tamarind seed extract (TSE). TSE exhibited cartilage and bone protecting nature by inhibiting the elevated activities of MMPs, HAase, exoglycosidases, cathepsins and TRAP. It also mitigated the augmented levels of inflammatory mediators like interleukin (IL)-1ß, tumor necrosis factor-α, IL-6, IL-23 and cyclooxygenase-2. Further, TSE administration alleviated increased levels of ROS and hydroperoxides and sustained the endogenous antioxidant homeostasis by balancing altered levels of endogenous antioxidant markers. Overall, TSE was observed as a potent agent abrogating arthritis-mediated cartilage/bone degradation, inflammation and associated stress in vivo demanding further attention.


Assuntos
Artrite Experimental/tratamento farmacológico , Osso e Ossos/efeitos dos fármacos , Cartilagem/efeitos dos fármacos , Inflamação/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Extratos Vegetais/uso terapêutico , Sementes/química , Tamarindus/embriologia , Animais , Osso e Ossos/patologia , Cartilagem/patologia , Mediadores da Inflamação/metabolismo , Extratos Vegetais/farmacologia , Ratos , Ratos Wistar
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