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2.
bioRxiv ; 2023 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-37502899

RESUMO

Obesity, a worldwide health problem, increases the risk for developing metabolic diseases such as insulin resistance and diabetes. It is well recognized that obesity-associated chronic inflammation plays a key role in the pathogenesis of systemic metabolic dysfunction. Previously, we revealed an anti-inflammatory role for spent culture supernatants isolated from the oral commensal bacterial species Streptococcus gordonii (Sg-SCS). Here, we identified that 6-hydroxyhexanoic acid (6-HHA), a medium chain fatty acid (MCFA), is the one of the key components of Sg-SCS . We found that treatment of 6-HHA in mice fed a high-fat diet (HFD) significantly reduced HFD-mediated weight gain which was largely attributed to a decrease in fat mass. Systemically, 6-HHA improves obesity-associated glucose intolerance and insulin resistance. Furthermore, administration of 6-HHA suppressed obesity-associated systemic inflammation and dyslipidemia. At the cellular level, treatment of 6-HHA ameliorated aberrant inflammatory and metabolic transcriptomic signatures in white adipose tissue of mice with diet-induced obesity (HFD). Mechanistically, we found that 6-HHA suppressed adipocyte-proinflammatory cytokine production and lipolysis, the latter through Gαi-mediated signaling. This work provides direct evidence for the anti-obesity effects of a novel MCFA, which could be a new therapeutic treatment for combating obesity. KEY POINTS: Hydroxyhexanoic medium chain fatty acids (MCFAs) are dietary and bacterial-derived energy sources, however, the outcomes of using MCFAs in treating metabolic disorders are diverse and complex. The MCFA 6-hydroxyhexanoic acid (6-HHA) is a metabolite secreted by the oral bacterial commensal species Streptococcus gordonii; here we investigated its role in modulating high-fat diet (HFD)-induced metabolic dysfunction. In a murine model of obesity, we found 6-HHA-mediated improvement of diet-mediated adiposity, insulin resistance and inflammation were in part due to actions on white adipose tissue (WAT).6-HHA suppressed proinflammatory cytokine production and lipolysis through Gi-mediated signaling in differentiated white adipocytes.

3.
Free Radic Biol Med ; 187: 204, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35662482

RESUMO

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Authors and Editor-in-Chief. Some of the data presented in Figure 6C, F and G of the above-titled paper were reported incorrectly in the published article. After being contacted by the Journal, the authors discovered an unintentional error in how the original data were analyzed that could affect the accuracy of the subsequent analysis. The raw data were incorrectly grouped in the analysis software, thereby altering the comparisons. Therefore the authors wish to retract the paper and will recollect and reanalyze the data appropriately. The authors apologize for any inconvenience.

4.
Free Radic Biol Med ; 188: 468, 2022 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-35718632

RESUMO

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Authors and Editor-in-Chief. Some of the data presented in Figure 6C, F and G of the paper to which this corrigendum relates were reported incorrectly in the published article. After being contacted by the Journal, the authors discovered an unintentional error in how the original data were analyzed that could affect the accuracy of the subsequent analysis. The raw data were incorrectly grouped in the analysis software, thereby altering the comparisons. Therefore the authors wish to retract the paper and corrigendum and will recollect and reanalyze the data appropriately. The authors apologize for any inconvenience.

6.
Cell Rep ; 37(7): 110003, 2021 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-34788615

RESUMO

Brown adipose tissue (BAT) thermogenic activity is tightly regulated by cellular redox status, but the underlying molecular mechanisms are incompletely understood. Protein S-nitrosylation, the nitric-oxide-mediated cysteine thiol protein modification, plays important roles in cellular redox regulation. Here we show that diet-induced obesity (DIO) and acute cold exposure elevate BAT protein S-nitrosylation, including UCP1. This thermogenic-induced nitric oxide bioactivity is regulated by S-nitrosoglutathione reductase (GSNOR; alcohol dehydrogenase 5 [ADH5]), a denitrosylase that balances the intracellular nitroso-redox status. Loss of ADH5 in BAT impairs cold-induced UCP1-dependent thermogenesis and worsens obesity-associated metabolic dysfunction. Mechanistically, we demonstrate that Adh5 expression is induced by the transcription factor heat shock factor 1 (HSF1), and administration of an HSF1 activator to BAT of DIO mice increases Adh5 expression and significantly improves UCP1-mediated respiration. Together, these data indicate that ADH5 controls BAT nitroso-redox homeostasis to regulate adipose thermogenesis, which may be therapeutically targeted to improve metabolic health.


Assuntos
Tecido Adiposo Marrom/metabolismo , Álcool Desidrogenase/metabolismo , Óxido Nítrico/metabolismo , Álcool Desidrogenase/fisiologia , Animais , Dieta , Células HEK293 , Homeostase/fisiologia , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Obesos , Óxido Nítrico/química , Obesidade/metabolismo , Oxirredução , Espécies Reativas de Oxigênio/metabolismo , Termogênese/fisiologia , Proteína Desacopladora 1/metabolismo , Proteína Desacopladora 1/fisiologia
8.
Autophagy ; 17(8): 1841-1855, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-32597296

RESUMO

Defective macroautophagy/autophagy and a failure to initiate the adaptive unfolded protein response (UPR) in response to the endoplasmic reticulum (ER) stress contributes to obesity-associated metabolic dysfunction. However, whether and how unresolved ER stress leads to defects in the autophagy pathway and to the progression of obesity-associated hepatic pathologies remains unclear. Obesity suppresses the expression of hepatic spliced XBP1 (X-box binding protein 1; sXBP1), the key transcription factor that promotes the adaptive UPR. Our RNA-seq analysis revealed that sXBP1 regulates genes involved in lysosomal function in the liver under fasting conditions. Chromatin immunoprecipitation (ChIP) analyzes of both primary hepatocytes and whole livers further showed that sXBP1 occupies the -743 to -523 site of the promoter of Tfeb (transcription factor EB), a master regulator of autophagy and lysosome biogenesis. Notably, this occupancy was significantly reduced in livers from patients with steatosis. In mice, hepatic deletion of Xbp1 (xbp1 LKO) suppressed the transcription of Tfeb as well as autophagy, whereas hepatic overexpression of sXbp1 enhanced Tfeb transcription and autophagy. Moreover, overexpression of Tfeb in the xbp1 LKO mouse liver ameliorated glucose intolerance and steatosis in mice with diet-induced obesity (DIO). Conversely, loss of TFEB function impaired the protective role of sXBP1 in hepatic steatosis in mice with DIO. These data indicate that sXBP1-Tfeb signaling has direct functional consequences in the context of obesity. Collectively, our data provide novel insight into how two organelle stress responses are integrated to protect against obesity-associated metabolic dysfunction.Abbreviations: AAV8: adeno-associated virus serotype 8; ACTB: actin, beta; ANOVA: analysis of variance; ATF6: activating transcription factor-6; ATG: autophagy related; BECN1: beclin 1; BMI: body mass index; ChIP: chromatin immunoprecipitation; CLEAR: coordinated lysosomal expression and regulation; Cre: cre recombinase; DIO: diet-induced obesity; EBSS: Earle's balanced salt solution; EIF2AK3/PERK: eukaryotic translation initiation factor 2 alpha kinase 3; ER: endoplasmic reticulum; ERN1/IRE1: endoplasmic reticulum (ER) to nucleus signaling 1; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GFP: green fluorescent protein; HFD: high-fat diet; h: hours; HSCs: hepatic stellate cells; INS: insulin; L/A: ammonium chloride and leupeptin; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; mRNA: messenger RNA; NAFLD: nonalcoholic fatty liver disease; NASH: nonalcoholic steatohepatitis; RD: regular diet; RFP: red fluorescent protein; SERPINA7/TBG: serpin family A member 7; SQSTM1/p62: sequestome 1; sXbp1 LOE: liver-specific overexpression of spliced Xbp1; TFEB: transcription factor EB; TG: thapsigargin; TN: tunicamycin; UPR: unfolded protein response; wks: weeks; WT: wild type; XBP1: X-box binding protein 1; xbp1 LKO: liver-specific Xbp1 knockout.


Assuntos
Autofagia/fisiologia , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Proteína 1 de Ligação a X-Box/metabolismo , Animais , Autofagia/genética , Estresse do Retículo Endoplasmático , Humanos , Fígado/metabolismo , Lisossomos/metabolismo , Camundongos , Resposta a Proteínas não Dobradas/fisiologia
9.
Free Radic Biol Med ; 146: 287-298, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31711984

RESUMO

Damage to the microvascular endothelium is an important part of normal tissue injury after radiation exposure and driven by the production of pro-oxidants. The Ca2+/calmodulin-dependent protein kinase II is present in the mitochondrial matrix (mitoCaMKII) where it regulates Ca2+ uptake via the mitochondrial Ca2+ uniporter (MCU) and pro-oxidant production. Here, we demonstrate that radiation exposure disrupts endothelial cell barrier integrity in vitro, but can be abrogated by inhibition of mitoCaMKII, MCU, or opening of the mitochondrial transition pore. Scavenging of mitochondrial pro-oxidants with mitoTEMPO before, but not after irradiation, protected barrier function. Furthermore, markers of apoptosis and mitochondrial pro-oxidant production were elevated at 24 h following irradiation and abolished by mitoCaMKII inhibition. Endothelial barrier dysfunction was detected as early as 2 h after irradiation. Despite only mildly impaired mitochondrial respiration, the intracellular ATP levels were significantly reduced 4 h after irradiation and correlated with barrier function. MitoCaMKII inhibition improved intracellular ATP concentrations by increasing glycolysis. Finally, DNA double strand break repair and non-homologous end joining, two major drivers of ATP consumption after irradiation, were greatly increased but not significantly affected by mitoCaMKII inhibition. These findings support the hypothesis that mitoCaMKII activity is linked to mitochondrial pro-oxidant production, reduced ATP production, and loss of endothelial barrier function following irradiation. The inhibition of mitoCaMKII is a promising approach to limiting radiation-induced endothelial injury.


Assuntos
Canais de Cálcio , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina , Cálcio/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Endotélio/metabolismo , Mitocôndrias/metabolismo
10.
Sci Signal ; 12(579)2019 04 30.
Artigo em Inglês | MEDLINE | ID: mdl-31040260

RESUMO

The role of the mitochondrial Ca2+ uniporter (MCU) in physiologic cell proliferation remains to be defined. Here, we demonstrated that the MCU was required to match mitochondrial function to metabolic demands during the cell cycle. During the G1-S transition (the cycle phase with the highest mitochondrial ATP output), mitochondrial fusion, oxygen consumption, and Ca2+ uptake increased in wild-type cells but not in cells lacking MCU. In proliferating wild-type control cells, the addition of the growth factors promoted the activation of the Ca2+/calmodulin-dependent kinase II (CaMKII) and the phosphorylation of the mitochondrial fission factor Drp1 at Ser616 The lack of the MCU was associated with baseline activation of CaMKII, mitochondrial fragmentation due to increased Drp1 phosphorylation, and impaired mitochondrial respiration and glycolysis. The mitochondrial fission/fusion ratio and proliferation in MCU-deficient cells recovered after MCU restoration or inhibition of mitochondrial fragmentation or of CaMKII in the cytosol. Our data highlight a key function for the MCU in mitochondrial adaptation to the metabolic demands during cell cycle progression. Cytosolic CaMKII and the MCU participate in a regulatory circuit, whereby mitochondrial Ca2+ uptake affects cell proliferation through Drp1.


Assuntos
Canais de Cálcio/metabolismo , Proliferação de Células/fisiologia , Pontos de Checagem da Fase G1 do Ciclo Celular/fisiologia , Dinâmica Mitocondrial/fisiologia , Miócitos de Músculo Liso/metabolismo , Animais , Cálcio/metabolismo , Canais de Cálcio/genética , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Proliferação de Células/genética , Células Cultivadas , Dinaminas/metabolismo , Feminino , Pontos de Checagem da Fase G1 do Ciclo Celular/genética , Masculino , Camundongos Knockout , Dinâmica Mitocondrial/genética , Músculo Liso Vascular/citologia , Miócitos de Músculo Liso/citologia , Fosforilação
11.
FASEB J ; 33(1): 1138-1150, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30106602

RESUMO

Raf1/c-Raf is a well-characterized serine/threonine-protein kinase that links Ras family members with the MAPK/ERK signaling cascade. We have identified a novel splice isoform of human Raf1 that causes protein truncation and loss of the C-terminal kinase domain (Raf1-tr). We found that Raf1-tr has increased nuclear localization compared with full-length Raf1, and this finding was secondary to reduced binding of Raf1-tr to the cytoplasmic chaperone FK506 binding protein 5. We show that Raf1-tr has increased binding to DNA-dependent protein kinase (DNA-PK), which inhibits DNA-PK function and causes amplification of irradiation- and bleomycin-induced DNA damage. We found that the human colorectal cancer cell line, HCT-116, displayed reduced expression of Raf1-tr, and reintroduction of Raf1-tr sensitized the cells to bleomycin-induced apoptosis. Furthermore, we identified differential Raf1-tr expression in breast cancer cell lines and showed that breast cancer cells with increased Raf1-tr expression become sensitized to bleomycin-induced apoptosis. Collectively, these results demonstrate a novel Raf1 isoform in humans that has a unique noncanonical role in regulating the double-stranded DNA damage response pathway through modulation of DNA-PK function.-Nixon, B. R., Sebag, S. C., Glennon, M. S., Hall, E. J., Kounlavong, E. S., Freeman, M. L., Becker, J. R. Nuclear localized Raf1 isoform alters DNA-dependent protein kinase activity and the DNA damage response.


Assuntos
Núcleo Celular/metabolismo , Dano ao DNA , Proteína Quinase Ativada por DNA/metabolismo , Isoformas de Proteínas/metabolismo , Proteínas Proto-Oncogênicas c-raf/metabolismo , Processamento Alternativo , Antibióticos Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Bleomicina/farmacologia , Linhagem Celular Tumoral , DNA/efeitos dos fármacos , DNA/efeitos da radiação , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Células HEK293 , Humanos , Ligação Proteica , Transdução de Sinais , Proteínas de Ligação a Tacrolimo/metabolismo , Proteínas ras/metabolismo
12.
Exp Cell Res ; 362(2): 400-411, 2018 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-29225050

RESUMO

Mitochondria are increasingly recognized as key mediators of acute cellular stress responses in asthma. However, the distinct roles of regulators of mitochondrial physiology on allergic asthma phenotypes are currently unknown. The mitochondrial Ca2+ uniporter (MCU) resides in the inner mitochondrial membrane and controls mitochondrial Ca2+ uptake into the mitochondrial matrix. To understand the function of MCU in models of allergic asthma, in vitro and in vivo studies were performed using models of functional deficiency or knockout of MCU. In primary human respiratory epithelial cells, MCU inhibition abrogated mitochondrial Ca2+ uptake and reactive oxygen species (ROS) production, preserved the mitochondrial membrane potential and protected from apoptosis in response to the pleiotropic Th2 cytokine IL-13. Consequently, epithelial barrier function was maintained with MCU inhibition. Similarly, the endothelial barrier was preserved in respiratory epithelium isolated from MCU-/- mice after exposure to IL-13. In the ovalbumin-model of allergic airway disease, MCU deficiency resulted in decreased apoptosis within the large airway epithelial cells. Concordantly, expression of the tight junction protein ZO-1 was preserved, indicative of maintenance of epithelial barrier function. These data implicate mitochondrial Ca2+ uptake through MCU as a key controller of epithelial cell viability in acute allergic asthma.


Assuntos
Asma/genética , Canais de Cálcio/genética , Cálcio/metabolismo , Células Epiteliais/metabolismo , Interleucina-13/genética , Alérgenos/metabolismo , Animais , Apoptose/genética , Asma/metabolismo , Asma/patologia , Canais de Cálcio/efeitos dos fármacos , Sinalização do Cálcio/genética , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Sobrevivência Celular/genética , Modelos Animais de Doenças , Células Epiteliais/patologia , Humanos , Interleucina-13/imunologia , Potencial da Membrana Mitocondrial/genética , Camundongos , Mitocôndrias/genética , Mitocôndrias/metabolismo , Espécies Reativas de Oxigênio/metabolismo
13.
Mol Pharm ; 14(6): 2166-2175, 2017 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-28460526

RESUMO

Asthma is a common lung disease affecting over 300 million people worldwide and is associated with increased reactive oxygen species, eosinophilic airway inflammation, bronchoconstriction, and mucus production. Targeting of novel therapeutic agents to the lungs of patients with asthma may improve efficacy of treatments and minimize side effects. We previously demonstrated that Ca2+/calmodulin-dependent protein kinase (CaMKII) is expressed and activated in the bronchial epithelium of asthmatic patients. CaMKII inhibition in murine models of allergic asthma reduces key disease phenotypes, providing the rationale for targeted CaMKII inhibition as a potential therapeutic approach for asthma. Herein we developed a novel cationic nanoparticle (NP)-based system for delivery of the potent and specific CaMKII inhibitor peptide, CaMKIIN, to airways.1 CaMKIIN-loaded NPs abrogated the severity of allergic asthma in a murine model. These findings provide the basis for development of innovative, site-specific drug delivery therapies, particularly for treatment of pulmonary diseases such as asthma.


Assuntos
Asma/tratamento farmacológico , Asma/enzimologia , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/antagonistas & inibidores , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Animais , Sistemas de Liberação de Medicamentos/métodos , Ácido Láctico/química , Pulmão/metabolismo , Camundongos , Nanopartículas/química , Ácido Poliglicólico/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico
14.
JCI Insight ; 2(4): e90656, 2017 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-28239655

RESUMO

It remains unclear how perturbations in cardiomyocyte sarcomere function alter postnatal heart development. We utilized murine models that allowed manipulation of cardiac myosin-binding protein C (MYBPC3) expression at critical stages of cardiac ontogeny to study the response of the postnatal heart to disrupted sarcomere function. We discovered that the hyperplastic to hypertrophic transition phase of mammalian heart development was altered in mice lacking MYBPC3 and this was the critical period for subsequent development of cardiomyopathy. Specifically, MYBPC3-null hearts developed evidence of increased cardiomyocyte endoreplication, which was accompanied by enhanced expression of cell cycle stimulatory cyclins and increased phosphorylation of retinoblastoma protein. Interestingly, this response was self-limited at later developmental time points by an upregulation of the cyclin-dependent kinase inhibitor p21. These results provide valuable insights into how alterations in sarcomere protein function modify postnatal heart development and highlight the potential for targeting cell cycle regulatory pathways to counteract cardiomyopathic stimuli.


Assuntos
Proteínas de Transporte/genética , Crescimento Celular , Proliferação de Células/genética , Regulação da Expressão Gênica no Desenvolvimento/genética , Coração/crescimento & desenvolvimento , Miócitos Cardíacos/metabolismo , Sarcômeros/metabolismo , Animais , Cardiomiopatias/genética , Cardiomiopatias/metabolismo , Ciclo Celular , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Ciclinas/metabolismo , Hiperplasia , Hipertrofia , Camundongos , Miócitos Cardíacos/fisiologia , Fosforilação , Proteína do Retinoblastoma/metabolismo , Sarcômeros/fisiologia , Regulação para Cima
15.
JCI Insight ; 2(3): e88297, 2017 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-28194433

RESUMO

Excessive ROS promote allergic asthma, a condition characterized by airway inflammation, eosinophilic inflammation, and increased airway hyperreactivity (AHR). The mechanisms by which airway ROS are increased and the relationship between increased airway ROS and disease phenotypes are incompletely defined. Mitochondria are an important source of cellular ROS production, and our group discovered that Ca2+/calmodulin-dependent protein kinase II (CaMKII) is present in mitochondria and activated by oxidation. Furthermore, mitochondrial-targeted antioxidant therapy reduced the severity of allergic asthma in a mouse model. Based on these findings, we developed a mouse model of CaMKII inhibition targeted to mitochondria in airway epithelium. We challenged these mice with OVA or Aspergillus fumigatus. Mitochondrial CaMKII inhibition abrogated AHR, inflammation, and eosinophilia following OVA and A. fumigatus challenge. Mitochondrial ROS were decreased after agonist stimulation in the presence of mitochondrial CaMKII inhibition. This correlated with blunted induction of NF-κB, the NLRP3 inflammasome, and eosinophilia in transgenic mice. These findings demonstrate a pivotal role for mitochondrial CaMKII in airway epithelium in mitochondrial ROS generation, eosinophilic inflammation, and AHR, providing insights into how mitochondrial ROS mediate features of allergic asthma.


Assuntos
Antioxidantes/administração & dosagem , Asma/tratamento farmacológico , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/antagonistas & inibidores , Mitocôndrias/enzimologia , Peptídeos/administração & dosagem , Espécies Reativas de Oxigênio/metabolismo , Animais , Antioxidantes/farmacologia , Aspergillus fumigatus/patogenicidade , Asma/etiologia , Asma/genética , Asma/metabolismo , Células Cultivadas , Modelos Animais de Doenças , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Camundongos , Camundongos Transgênicos , Mitocôndrias/efeitos dos fármacos , NF-kappa B/genética , NF-kappa B/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Ovalbumina/efeitos adversos , Peptídeos/farmacologia
16.
Am J Physiol Lung Cell Mol Physiol ; 310(1): L86-94, 2016 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-26545899

RESUMO

The calcium and calmodulin-dependent kinase II (CaMKII) translates increases in intracellular Ca(2+) into downstream signaling events. Its function in pulmonary pathologies remains largely unknown. CaMKII is a well-known mediator of apoptosis and regulator of endoplasmic reticulum (ER) Ca(2+). ER stress and apoptosis of type II pneumocytes lead to aberrant tissue repair and progressive collagen deposition in pulmonary fibrosis. Thus we hypothesized that CaMKII inhibition alleviates fibrosis in response to bleomycin by attenuating apoptosis and ER stress of type II pneumocytes. We first established that CaMKII was strongly expressed in the distal respiratory epithelium, in particular in surfactant protein-C-positive type II pneumocytes, and activated after bleomycin instillation. We generated a novel transgenic model of inducible expression of the CaMKII inhibitor peptide AC3-I limited to type II pneumocytes (Tg SPC-AC3-I). Tg SPC-AC3-I mice were protected from development of pulmonary fibrosis after bleomycin exposure compared with wild-type mice. CaMKII inhibition also provided protection from apoptosis in type II pneumocytes in vitro and in vivo. Moreover, intracellular Ca(2+) levels and ER stress were increased by bleomycin and significantly blunted with CaMKII inhibition in vitro. These data demonstrate that CaMKII inhibition prevents type II pneumocyte apoptosis and development of pulmonary fibrosis in response to bleomycin. CaMKII inhibition may therefore be a promising approach to prevent or ameliorate the progression of pulmonary fibrosis.


Assuntos
Células Epiteliais Alveolares/efeitos dos fármacos , Apoptose/efeitos dos fármacos , Bleomicina/farmacologia , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/antagonistas & inibidores , Cálcio/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Fibrose Pulmonar/tratamento farmacológico , Células Epiteliais Alveolares/metabolismo , Animais , Retículo Endoplasmático/efeitos dos fármacos , Retículo Endoplasmático/metabolismo , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Estresse do Retículo Endoplasmático/fisiologia , Camundongos Transgênicos , Fibrose Pulmonar/metabolismo , Fibrose Pulmonar/patologia
17.
J Biol Chem ; 288(11): 7875-7884, 2013 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-23362270

RESUMO

Previous studies have shown that the innate immune stimulant LPS augments mechanical ventilation-induced pulmonary coagulation and inflammation. Whether these effects are mediated by alveolar epithelial cells is unclear. The alveolar epithelium is a key regulator of the innate immune reaction to pathogens and can modulate both intra-alveolar inflammation and coagulation through up-regulation of proinflammatory cytokines and tissue factor (TF), the principal initiator of the extrinsic coagulation pathway. We hypothesized that cyclic mechanical stretch (MS) potentiates LPS-mediated alveolar epithelial cell (MLE-12) expression of the chemokine keratinocyte-derived cytokine (KC) and TF. Contrary to our hypothesis, MS significantly decreased LPS-induced KC and TF mRNA and protein expression. Investigation into potential mechanisms showed that stretch significantly reduced LPS-induced surface expression of TLR4 that was not a result of increased degradation. Decreased cell surface TLR4 expression was concomitant with reduced LPS-mediated NF-κB activation. Immunofluorescence staining showed that cyclic MS markedly altered LPS-induced organization of actin filaments. In contrast to expression, MS significantly increased LPS-induced cell surface TF activity independent of calcium signaling. These findings suggest that cyclic MS of lung epithelial cells down-regulates LPS-mediated inflammatory and procoagulant expression by modulating actin organization and reducing cell surface TLR4 expression and signaling. However, because LPS-induced surface TF activity was enhanced by stretch, these data demonstrate differential pathways regulating TF expression and activity. Ultimately, loss of LPS responsiveness in the epithelium induced by MS could result in increased susceptibility of the lung to bacterial infections in the setting of mechanical ventilation.


Assuntos
Quimiocinas/metabolismo , Coagulantes/metabolismo , Células Epiteliais/citologia , Queratinócitos/citologia , Lipopolissacarídeos/metabolismo , Pulmão/metabolismo , Tromboplastina/biossíntese , Animais , Linhagem Celular , Sobrevivência Celular , Ensaio de Imunoadsorção Enzimática/métodos , Inflamação , Camundongos , NF-kappa B/metabolismo , Transdução de Sinais , Tromboplastina/metabolismo , Receptor 4 Toll-Like/metabolismo , Receptores Toll-Like/metabolismo
18.
Thorax ; 67(12): 1032-9, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23033361

RESUMO

BACKGROUND: Systemic blockade of tissue factor (TF) attenuates acute lung injury (ALI) in animal models of sepsis but the effects of global TF deficiency are unknown. We used mice with complete knockout of mouse TF and low levels (∼1%) of human TF (LTF mice) to test the hypothesis that global TF deficiency attenuates lung inflammation in direct lung injury. METHODS: LTF mice were treated with 10 µg of lipopolysaccharide (LPS) or vehicle administered by direct intratracheal injection and studied at 24 h. RESULTS: Contrary to our hypothesis, LTF mice had increased lung inflammation and injury as measured by bronchoalveolar lavage cell count (3.4×10(5) wild-type (WT) LPS vs 3.3×10(5) LTF LPS, p=0.947) and protein (493 µg/ml WT LPS vs 1014 µg/ml LTF LPS, p=0.006), proinflammatory cytokines (TNF-α, IL-10, IL-12, p<0.035 WT LPS vs LTF LPS) and histology compared with WT mice. LTF mice also had increased haemorrhage and free haemoglobin in the airspace accompanied by increased oxidant stress as measured by lipid peroxidation products (F(2) isoprostanes and isofurans). CONCLUSIONS: These findings indicate that global TF deficiency does not confer protection in a direct lung injury model. Rather, TF deficiency causes increased intra-alveolar haemorrhage following LPS leading to increased lipid peroxidation. Strategies to globally inhibit TF may be deleterious in patients with ALI.


Assuntos
Lesão Pulmonar Aguda/metabolismo , Hemorragia/metabolismo , Estresse Oxidativo , Alvéolos Pulmonares , Tromboplastina/deficiência , Análise de Variância , Animais , Western Blotting , Lavagem Broncoalveolar , Citocinas/metabolismo , Eletroforese em Gel de Poliacrilamida , Furanos/metabolismo , Hemoglobinas/metabolismo , Inflamação/metabolismo , Isoprostanos/metabolismo , Lipopolissacarídeos/administração & dosagem , Camundongos , Camundongos Knockout , Reação em Cadeia da Polimerase em Tempo Real , Estatísticas não Paramétricas
19.
Exp Lung Res ; 37(8): 509-17, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21913843

RESUMO

Fibrin deposition mediated through activation of tissue factor (TF) in the airspace is central to the pathogenesis of acute lung injury. Defining the mechanisms of TF regulation in the lung is critical to understanding pulmonary fibrin formation. Tumor necrosis factor-α (TNF-α) up-regulates TF in the injured lung, and there is emerging evidence that another cytokine, interferon-γ (IFN-γ), also modulates expression. The effects of TNF-α and IFN-γ on regulation of TF were studied in alveolar epithelial A549 cells. In addition, potential mechanisms of modulation of TF expression by the 2 cytokines were analyzed with the hypothesis that IFN-γ acts synergistically with TNF-α to up-regulate alveolar epithelial TF through modulation of TNF receptor (TNFR) expression. TNF-α but not IFN-γ treatment increased TF mRNA, protein, and cell surface TF activity. The combination of IFN-γ and TNF-α treatment augmented the effects of TNF-α on TF up-regulation and also increased release of procoagulant microparticles (MPs) from A549 cells. IFN-γ modulated expression of both TNF-α receptors. Studies utilizing neutralizing antibodies against the two TNF receptors showed that the TF effects were mediated primarily through augmentation of TNFR1-dependent cellular responses. These findings have important implications for regulation of fibrin formation in the lung in the setting of acute inflammation.


Assuntos
Células Epiteliais Alveolares/efeitos dos fármacos , Células Epiteliais Alveolares/metabolismo , Interferon gama/administração & dosagem , Tromboplastina/genética , Tromboplastina/metabolismo , Fator de Necrose Tumoral alfa/administração & dosagem , Linhagem Celular , Micropartículas Derivadas de Células/efeitos dos fármacos , Micropartículas Derivadas de Células/metabolismo , Sinergismo Farmacológico , Humanos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores Tipo I de Fatores de Necrose Tumoral/metabolismo , Receptores Tipo II do Fator de Necrose Tumoral/metabolismo , Regulação para Cima/efeitos dos fármacos
20.
Curr Pharm Biotechnol ; 12(9): 1481-96, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21401517

RESUMO

Acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) are characterized by excessive intraalveolar fibrin deposition, driven, at least in part by inflammation. The imbalance between activation of coagulation and inhibition of fibrinolysis in patients with ALI/ARDS favors fibrin formation and appears to occur both systemically and in the lung and airspace. Tissue factor (TF), a key mediator of the activation of coagulation in the lung, has been implicated in the pathogenesis of ALI/ARDS. As such, there have been numerous investigations modulating TF activity in a variety of experimental systems in order to develop new therapeutic strategies for ALI/ARDS. This review will summarize current understanding of the role of TF and other proteins of the coagulation cascade as well the fibrinolysis pathway in the development of ALI/ARDS with an emphasis on the pathways that are potential therapeutic targets. These include the TF inhibitor pathway, the protein C pathway, antithrombin, heparin, and modulation of fibrinolysis through plasminogen activator- 1 (PAI-1) or plasminogen activators (PA). Although experimental studies show promising results, clinical trials to date have proven unsuccessful in improving patient outcomes. Modulation of coagulation and fibrinolysis has complex effects on both hemostasis and inflammatory pathways and further studies are needed to develop new treatment strategies for patients with ALI/ARDS.


Assuntos
Lesão Pulmonar Aguda/fisiopatologia , Coagulação Sanguínea/fisiologia , Síndrome do Desconforto Respiratório/fisiopatologia , Lesão Pulmonar Aguda/tratamento farmacológico , Animais , Antitrombinas/farmacologia , Fator VIIa/farmacologia , Heparina/farmacologia , Humanos , Inflamação/metabolismo , Proteína C/farmacologia , Proteínas Recombinantes/farmacologia , Síndrome do Desconforto Respiratório/tratamento farmacológico , Tromboplastina/fisiologia
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