RESUMO
The combustion of fossil fuels contributes to air pollution (AP), which was linked to about 8.79 million global deaths in 2018, mainly due to respiratory and cardiovascular-related effects. Among these, particulate air pollution (PM2.5) stands out as a major risk factor for heart health, especially during vulnerable phases. Our prior study showed that premature exposure to 1,2-naphthoquinone (1,2-NQ), a chemical found in diesel exhaust particles (DEP), exacerbated asthma in adulthood. Moreover, increased concentration of 1,2-NQ contributed to airway inflammation triggered by PM2.5, employing neurogenic pathways related to the up-regulation of transient receptor potential vanilloid 1 (TRPV1). However, the potential impact of early-life exposure to 1,2-naphthoquinone (1,2-NQ) on atrial fibrillation (AF) has not yet been investigated. This study aims to investigate how inhaling 1,2-NQ in early life affects the autonomic adrenergic system and the role played by TRPV1 in these heart disturbances. C57Bl/6 neonate male mice were exposed to 1,2-NQ (100 nM) or its vehicle at 6, 8, and 10 days of life. Early exposure to 1,2-NQ impairs adrenergic responses in the right atria without markedly affecting cholinergic responses. ECG analysis revealed altered rhythmicity in young mice, suggesting increased sympathetic nervous system activity. Furthermore, 1,2-NQ affected ß1-adrenergic receptor agonist-mediated positive chronotropism, which was prevented by metoprolol, a ß1 receptor blocker. Capsazepine, a TRPV1 blocker but not a TRPC5 blocker, reversed 1,2-NQ-induced cardiac changes. In conclusion, neonate mice exposure to AP 1,2-NQ results in an elevated risk of developing cardiac adrenergic dysfunction, potentially leading to atrial arrhythmia at a young age.
Assuntos
Poluentes Atmosféricos , Naftoquinonas , Masculino , Animais , Camundongos , Poluentes Atmosféricos/toxicidade , Adrenérgicos , Células Receptoras Sensoriais , Átrios do Coração , PoeiraRESUMO
Thioredoxin plays an essential role in bacterial antioxidant machinery and virulence; however, its regulatory actions in the host are less well understood. Reduced human Trx activates transient receptor potential canonical 5 (TRPC5) in inflammation, but there is no evidence of whether these receptors mediate bacterial thioredoxin effects in the host. Importantly, TRPC5 can form functional complexes with other subunits such as TRPC4. Herein, E. coli-derived thioredoxin induced mortality in lipopolysaccharide- (LPS-) injected mice, accompanied by reduction of leukocyte accumulation, regulation of cytokine release into the peritoneum, and impairment of peritoneal macrophage-mediated phagocytosis. Dual TRPC4/TRPC5 blockade by ML204 increased mortality and hypothermia in thioredoxin-treated LPS mice but preserved macrophage's ability to phagocytose. TRPC5 deletion did not alter body temperature but promoted additional accumulation of peritoneal leukocytes and inflammatory mediator release in thioredoxin-administered LPS mice. Thioredoxin diminished macrophage-mediated phagocytosis in wild-type but not TRPC5 knockout animals. TRPC5 ablation did not affect LPS-induced responses. However, ML204 caused mortality associated with exacerbated hypothermia and decreased peritoneal leukocyte numbers and cytokines in LPS-injected mice. These results suggest that bacterial thioredoxin effects under LPS stimuli are mediated by TRPC4 and TRPC5, shedding light on the additional mechanisms of bacterial virulence and on the pathophysiological roles of these receptors.
Assuntos
Escherichia coli/química , Lipopolissacarídeos/toxicidade , Síndrome de Resposta Inflamatória Sistêmica/metabolismo , Canais de Cátion TRPC/metabolismo , Tiorredoxinas/uso terapêutico , Animais , Peróxido de Hidrogênio/metabolismo , Indóis/toxicidade , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Óxido Nítrico/metabolismo , Fagocitose/efeitos dos fármacos , Piperidinas/toxicidade , Síndrome de Resposta Inflamatória Sistêmica/induzido quimicamente , Canais de Cátion TRPC/antagonistas & inibidores , Virulência/efeitos dos fármacosRESUMO
Patients with rheumatoid arthritis (RA) suffer from pain and joint disability. The transient receptor potential ankyrin 1 (TRPA1) channel expressed on sensory neurones and non-neuronal cells mediates pain transduction and inflammation and it has been implicated in RA. However, there is little information on the contribution of TRPA1 for human disease. Here, we investigated the expression of TRPA1 on peripheral blood leukocytes and the circulating levels of its endogenous activators 4-hydroxynonenal (4-HNE) and hydrogen peroxide (H2O2) in RA patients treated or not with the anti-rheumatic leflunomide (LFN) or the anti-TNFα adalimumab (ADA). We also assessed whether TRPA1 expression correlates with joint pain and disability, in addition to the immune changes in RA. TRPA1 expression on peripheral blood leukocytes correlated with pain severity and disability. TRPA1 levels on these cells were associated with the numbers of polymorphonuclear and the activation of CD14+ cells. No correlations were found between the lymphocyte population and TRPA1 expression, pain or disability. Patients recently diagnosed with RA expressed increased levels of TRPA1 on their leukocytes whilst treatment with either LFN or ADA down-regulated this receptor probably by reducing the numbers of polymorphonuclears and the activation of CD14+ cells. We suggest that the activation levels of CD14+ cells, the numbers of PMNs in the peripheral blood and the expression of TRPA1 on peripheral blood leukocytes correlate with RA progression, affecting joint pain sensitivity and loss of function.
RESUMO
High diesel exhaust particle levels are associated with increased health effects; however, knowledge on the impact of its chemical contaminant 1,2-naphthoquinone (1,2-NQ) is limited. We investigated whether postnatal and adult exposures to 1,2-NQ influence allergic reaction and the roles of innate and adaptive immunity. Male neonate (6 days) and adult (56 days) C57Bl/6 mice were exposed to 1,2-NQ (100 nM; 15 min) for 3 days, and on day 59, they were sensitized and later challenged with ovalbumin (OVA). Airway hyper-responsiveness (AHR) and production of cytokines, immunoglobulin E (IgE) and leukotriene B4 (LTB4) were measured in the airways. Postnatal exposure to 1,2-NQ activated dendritic cells in splenocytes by increasing expressing cell surface molecules (e.g., CD11c). Co-exposure to OVA effectively polarized T helper (Th) type 2 (Th2) by secreting Th2-mediated cytokines. Re-stimulation with unspecific stimuli (PMA and ionomycin) generated a mixed Th1 (CD4(+)/IFN-γ(+)) and Th17 (CD4(+)/IL-17(+)) phenotype in comparison with the vehicle-matched group. Postnatal exposure to 1,2-NQ did not induce eosinophilia in the airways at adulthood, although it evoked neutrophilia and exacerbated OVA-induced eosinophilia, Th2 cytokines, IgE and LTB4 production without affecting AHR and mast cell degranulation. At adulthood, 1,2-NQ exposure evoked neutrophilia and increased Th1/Th2 cytokine levels, but failed to affect OVA-induced eosinophilia. In conclusion, postnatal exposure to 1,2-NQ increases the susceptibility to antigen-induced asthma. The mechanism appears to be dependent on increased expression of co-stimulatory molecules, which leads to cell presentation amplification, Th2 polarization and enhanced LTB4, humoral response and Th1/Th2 cytokines. These findings may be useful for future investigations on treatments focused on pulmonary illnesses observed in children living in heavy polluted areas.
Assuntos
Envelhecimento/imunologia , Poluentes Atmosféricos/toxicidade , Exposição por Inalação/efeitos adversos , Naftoquinonas/toxicidade , Pneumonia/induzido quimicamente , Hipersensibilidade Respiratória/induzido quimicamente , Emissões de Veículos/toxicidade , Imunidade Adaptativa/efeitos dos fármacos , Envelhecimento/efeitos dos fármacos , Animais , Animais Recém-Nascidos , Citocinas/imunologia , Suscetibilidade a Doenças/induzido quimicamente , Imunidade Inata/efeitos dos fármacos , Imunoglobulina E/imunologia , Exposição por Inalação/análise , Leucotrieno B4/imunologia , Masculino , Ovalbumina/imunologia , Pneumonia/imunologia , Hipersensibilidade Respiratória/imunologia , Emissões de Veículos/análiseRESUMO
The underlying mechanisms of itch are poorly understood. We have investigated a model involving the chemoattractant leukotriene B4 (LTB4) that is up-regulated in common skin diseases. Intradermal injection of LTB4 (0.1 nmol/site) into female CD1 mice induced significant scratching movements (used as an itch index) compared with vehicle-injected (0.1% bovine serum albumin-saline) mice. Intraperitoneal transient receptor potential (TRP) channel antagonist treatment significantly inhibited itch as follows: TRP vanilloid 1 (TRPV1) antagonist SB366791 (0.5 mg/kg, by 97%) and the TRP ankyrin 1 (TRPA1) antagonists TCS 5861528 (10 mg/kg; 82%) and HC-030031 (100 mg/kg; 76%). Leukotriene B4 receptor 2 antagonism by LY255283 (5 mg/kg i.p.; 62%) reduced itch. Neither TRPV1-knockout (TRPV1-KO) nor TRPA1-knockout (TRPA1-KO mice exhibited LTB4-induced itch compared with their wild-type counterparts. The reactive oxygen species scavengers N-acetylcysteine (NAC; 204 mg/kg i.p.; 86%) or superoxide dismutase (SOD; 10 mg/kg i.p.; 83%) also inhibited itch. LTB4-induced superoxide release was attenuated by TCS 5861528 (56%) and HC-030031 (66%), NAC (58%), SOD (50%), and LY255283 (59%) but not by the leukotriene B4 receptor 1 antagonist U-75302 (9 nmol/site) or SB366791. Itch, superoxide, and myeloperoxidase generation were inhibited by the leukocyte migration inhibitor fucoidan (10 mg/kg i.v.) by 80, 61, and 34%, respectively. Myeloperoxidase activity was also reduced by SB366791 (35%) and SOD (28%). TRPV1-KO mice showed impaired myeloperoxidase release, whereas TRPA1-KO mice exhibited diminished production of superoxide. This result provides novel evidence that TRPA1 and TRPV1 contribute to itch via distinct mechanisms.
Assuntos
Leucócitos/metabolismo , Leucotrieno B4/farmacologia , Superóxidos/metabolismo , Canais de Potencial de Receptor Transitório/metabolismo , Animais , Anquirinas/farmacologia , Feminino , Leucócitos/efeitos dos fármacos , Camundongos , Camundongos Knockout , Prurido/tratamento farmacológico , Prurido/metabolismo , Receptores do Leucotrieno B4/antagonistas & inibidores , Canais de Cátion TRPV/metabolismoRESUMO
The environmental chemical 1,2-naphthoquinone (1,2-NQ) is implicated in the exacerbation of airways diseases induced by exposure to diesel exhaust particles (DEP), which involves a neurogenic-mediated mechanism. Plasma extravasation in trachea, main bronchus and lung was measured as the local (125)I-bovine albumin accumulation. RT-PCR quantification of TRPV1 and tachykinin (NK(1) and NK(2)) receptor gene expression were investigated in main bronchus. Intratracheal injection of DEP (1 and 5 mg/kg) or 1,2-NQ (35 and 100 nmol/kg) caused oedema in trachea and bronchus. 1,2-NQ markedly increased the DEP-induced responses in the rat airways in an additive rather than synergistic manner. This effect that was significantly reduced by L-732,138, an NK(1) receptor antagonist, and in a lesser extent by SR48968, an NK(2) antagonist. Neonatal capsaicin treatment also markedly reduced DEP and 1,2-NQ-induced oedema. Exposure to pollutants increased the TRPV1, NK(1) and NK(2) receptors gene expression in bronchus, an effect was partially suppressed by capsaicin treatment. In conclusion, our results are consistent with the hypothesis that DEP-induced airways oedema is highly influenced by increased ambient levels of 1,2-NQ and takes place by neurogenic mechanisms involving up-regulation of TRPV1 and tachykinin receptors.
Assuntos
Naftoquinonas/toxicidade , Neurônios Aferentes/efeitos dos fármacos , Sistema Respiratório/efeitos dos fármacos , Canais de Cátion TRPV/metabolismo , Emissões de Veículos/toxicidade , Poluentes Atmosféricos/toxicidade , Animais , Feminino , Inflamação/metabolismo , Masculino , Neurônios Aferentes/metabolismo , Ratos , Ratos Wistar , Sistema Respiratório/inervação , Sistema Respiratório/metabolismoRESUMO
We investigated the contribution of neutrophils to joint hyperalgesia and peroxynitrite formation in zymosan arthritis. Rats received 1 mg zymosan intra-articular, and joint hyperalgesia was measured using the rat knee-joint articular incapacitation test. After 6 h, joint exudates were collected by aspiration for the assessment of cell influx, myeloperoxidase activity, and nitrite (as an index of nitric oxide formation) levels. Nitrotyrosine content, used as an index of peroxynitrite formation, was measured in joint exudates, using enzyme-linked immunosorbent assay. A group of rats was rendered neutropenic through the administration of a rabbit anti-rat neutrophil antibody (2 ml kg(-1), i.p.) 30 min before injection of 1 mg zymosan intra-articular. Other groups received uric acid (100 or 250 mg kg(-1), i.p.), the peroxynitrite scavenger, 30 min before 1 mg zymosan intra-articular. Controls received the vehicle. The significant inhibition of joint hyperalgesia in neutropenic animals was associated to significantly decreased cell influx, myeloperoxidase activity, nitric oxide, and nitrotyrosine levels in the joint exudates, as compared to naive rats. Uric acid administration inhibited both hyperalgesia and cell influx, as compared to controls. Neutrophils are involved in both nitric oxide and peroxynitrite formation in zymosan arthritis, thereby contributing to acute joint hyperalgesia. Scavenging of reactive nitrogen species (e.g. peroxynitrite) inhibits neutrophil migration and joint hyperalgesia in the acute phase of zymosan arthritis in rats.
Assuntos
Artrite Experimental/metabolismo , Hiperalgesia/metabolismo , Neutrófilos/metabolismo , Ácido Peroxinitroso/metabolismo , Zimosan/toxicidade , Doença Aguda , Animais , Artrite Experimental/induzido quimicamente , Membro Posterior/metabolismo , Membro Posterior/patologia , Hiperalgesia/sangue , Injeções Intra-Articulares , Articulação do Joelho/efeitos dos fármacos , Articulação do Joelho/metabolismo , Articulação do Joelho/patologia , Masculino , Óxido Nítrico/metabolismo , Peroxidase/metabolismo , Ratos , Ratos Wistar , Espécies Reativas de Nitrogênio/metabolismo , Líquido Sinovial/metabolismo , Tirosina/análogos & derivados , Tirosina/metabolismo , Ácido Úrico/administração & dosagem , Ácido Úrico/sangue , Zimosan/administração & dosagemRESUMO
1. The contribution of nitric oxide (NO) and peroxynitrite (PN) to inflammation in a zymosan-induced (1 mg, intra-articular, i.art.) rat model of arthritis was assessed by histopathology and by measuring the glycosaminoglycan (GAG) content of the articular cartilage. 2. Progression of the chronic synovitis in zymosan-induced arthritis (ZYA) was associated with increased nitrite and nitrotyrosine (3-NT) levels in the joint exudates that paralleled a progressive loss of the GAG content. An increase in 3-NT was also observed after i.art. PN. 3. The nonselective nitric oxide synthase (NOS) inhibitor l-N(G)-nitroarginine methyl ester (25-75 mg x kg(-1)day(-1)) or the selective inducible NOS inhibitor aminoguanidine (50-100 mg x kg(-1)day(-1)) given 1 h before (prophylactic) or 3 days after (therapeutic) injection of the zymosan ameliorated the synovitis, but worsened the GAG loss, as measured at the end of the experiment (day 7). 4. The PN scavenger uric acid (100-250 mg x kg(-1) i.p. four times daily) given prophylactically until the end of the experiment (day 14), in a dose compatible with its PN scavenging activity, significantly decreased both the synovitis and the GAG loss. 5. In conclusion, PN formation is associated with cartilage damage in addition to proinflammatory activity in ZYA. NOS inhibitors and a PN scavenger were able to reduce the cellular infiltration, while displaying opposite effects on cartilage homeostasis either by enhancing or ameliorating the damage, respectively.
Assuntos
Artrite Experimental/induzido quimicamente , Cartilagem Articular/efeitos dos fármacos , Sequestradores de Radicais Livres/uso terapêutico , Óxido Nítrico/efeitos adversos , Espécies Reativas de Nitrogênio/antagonistas & inibidores , Tirosina/análogos & derivados , Zimosan/efeitos adversos , Animais , Cartilagem Articular/patologia , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Sequestradores de Radicais Livres/farmacologia , Glicosaminoglicanos/antagonistas & inibidores , Glicosaminoglicanos/química , Glicosaminoglicanos/metabolismo , Guanidinas/farmacologia , Guanidinas/uso terapêutico , Injeções Intra-Articulares , Injeções Intraperitoneais , Masculino , NG-Nitroarginina Metil Éster/administração & dosagem , NG-Nitroarginina Metil Éster/farmacologia , NG-Nitroarginina Metil Éster/uso terapêutico , Óxido Nítrico/antagonistas & inibidores , Óxido Nítrico/química , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase/farmacologia , Óxido Nítrico Sintase/uso terapêutico , Nitritos/antagonistas & inibidores , Nitritos/química , Ácido Peroxinitroso/administração & dosagem , Ácido Peroxinitroso/farmacologia , Ratos , Ratos Wistar , Espécies Reativas de Nitrogênio/uso terapêutico , Líquido Sinovial/química , Líquido Sinovial/efeitos dos fármacos , Líquido Sinovial/metabolismo , Membrana Sinovial/efeitos dos fármacos , Membrana Sinovial/fisiopatologia , Membrana Sinovial/ultraestrutura , Sinovite/induzido quimicamente , Sinovite/tratamento farmacológico , Tirosina/antagonistas & inibidores , Tirosina/biossíntese , Tirosina/química , Ácido Úrico/administração & dosagem , Ácido Úrico/sangue , Ácido Úrico/farmacologia , Zimosan/administração & dosagemRESUMO
The leukocyte migration induced by Phoneutria nigriventer spider venom (PNV) has been investigated in rats using the pleurisy model. Intrapleural injection of PNV (10-100 microg/cavity) caused a dose- and time-dependent leukocyte accumulation. The bradykinin B(2) receptor antagonist Hoe 140 (0.5 mg/kg) substantially inhibited PNV-induced cell accumulation, whereas the angiotensin-converting enzyme inhibitor captopril (2 mg/kg) potentiated by 80% this effect. The non-specific kallikrein inhibitor aprotinin and the plasma kallikrein inhibitor soybean trypsin inhibitor greatly reduced PNV-induced leukocyte migration, whereas the selective tissue kallikrein inhibitor P(ac)-F-S-R-EDDnp failed to affect PNV-induced responses. Treatment of rats with capsaicin (50 mg/kg) at the neonatal stage resulted in 67% inhibition of the PNV-induced cell migration. The neurokinin NK(1) receptor antagonist SR140333, but not the NK(2) receptor antagonist SR48968, reduced by 55% venom-induced cell accumulation. We conclude that bradykinin generation is involved in the PNV-induced pleural leukocyte migration in rats, where it can directly activate sensory nerves contributing to a neurogenic inflammatory mechanism.