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Non-small cell lung cancers (NSCLCs) demonstrate intrinsic resistance to cell death, even after chemotherapy. Previous work suggested defective nuclear translocation of active caspase-3 in observed resistance to cell death. We have identified mitogen-activated protein kinase-activated protein kinase 2 (MK2; encoded by the gene MAPKAPK2) is required for caspase-3 nuclear translocation in the execution of apoptosis in endothelial cells. The objective was to determine MK2 expression in NSCLCs and the association between MK2 and clinical outcomes in patients with NSCLC. Clinical and MK2 mRNA data were extracted from two demographically distinct NSCLC clinical cohorts, North American (The Cancer Genome Atlas, TCGA) and East Asian (EA). Tumor responses following first round of chemotherapy were dichotomized as clinical response (complete response, partial response, and stable disease) or progression of disease. Multivariable survival analyses were performed using Cox proportional hazard ratios and Kaplan-Meier curves. NSCLC exhibited lower MK2 expression than SCLC cell lines. In patients, lower tumor MK2 transcript levels were observed in those presenting with late-stage NSCLC. Higher MK2 expression was associated with clinical response following initial chemotherapy and independently associated with improved 2-yr survival in two distinct cohorts, 0.52 (0.28-0.98) and 0.1 (0.01-0.81), TCGA and EA, respectively, even after adjusting for common oncogenic driver mutations. Survival benefit of higher MK2 expression was unique to lung adenocarcinoma when comparing across various cancers. This study implicates MK2 in apoptosis resistance in NSCLC and suggests prognostic value of MK2 transcript levels in patients with lung adenocarcinoma.
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Adenocarcinoma de Pulmão , Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Humanos , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/genética , Caspase 3/uso terapêutico , Células Endoteliais , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genéticaRESUMO
We have previously identified mitogen-activated protein kinase-activated protein kinase 2 (MK2) is required for caspase-3 nuclear translocation in the execution of apoptosis; however, little is known of the underlying mechanisms. Therefore, we sought to determine the role of kinase and nonkinase functions of MK2 in promoting nuclear translocation of caspase-3. We identified two non-small cell lung cancer cell lines for use in these experiments based on low MK2 expression. Wild-type, enzymatic and cellular localization mutant MK2 constructs were expressed using adenoviral infection. Cell death was evaluated by flow cytometry. In addition, cell lysates were harvested for protein analyses. Phosphorylation of caspase-3 was determined using two-dimensional gel electrophoresis followed by immunoblotting and in vitro kinase assay. Association between MK2 and caspase-3 was evaluated using proximity-based biotin ligation assays and co-immunoprecipitation. Overexpression of MK2 resulted in nuclear translocation of caspase-3 and caspase-3-mediated apoptosis. MK2 directly phosphorylates caspase-3; however, phosphorylation status of caspase-3 or MK2-dependent phosphorylation of caspase-3 did not alter caspase-3 activity. The enzymatic function of MK2 was dispensable in nuclear translocation of caspase-3. MK2 and caspase-3 associated together and a nonenzymatic function of MK2, chaperoned nuclear trafficking, is required for caspase-3-mediated apoptosis. Taken together, our results demonstrate a nonenzymatic role for MK2 in the nuclear translocation of caspase-3. Furthermore, MK2 may function as a molecular switch in regulating the transition between the cytosolic and nuclear functions of caspase-3.
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Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Humanos , Apoptose , Caspase 3/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Fosforilação , Proteínas Serina-Treonina Quinases/metabolismoRESUMO
Neutrophils play a significant role in determining disease severity following SARS-CoV-2 infection. Gene and protein expression defines several neutrophil clusters in COVID-19, including the emergence of low density neutrophils (LDN) that are associated with severe disease. The functional capabilities of these neutrophil clusters and correlation with gene and protein expression are unknown. To define host defense and immunosuppressive functions of normal density neutrophils (NDN) and LDN from COVID-19 patients, we recruited 64 patients with severe COVID-19 and 26 healthy donors (HD). Phagocytosis, respiratory burst activity, degranulation, neutrophil extracellular trap (NET) formation, and T-cell suppression in those neutrophil subsets were measured. NDN from severe/critical COVID-19 patients showed evidence of priming with enhanced phagocytosis, respiratory burst activity, and degranulation of secretory vesicles and gelatinase and specific granules, while NET formation was similar to HD NDN. COVID LDN response was impaired except for enhanced NET formation. A subset of COVID LDN with intermediate CD16 expression (CD16Int LDN) promoted T cell proliferation to a level similar to HD NDN, while COVID NDN and the CD16Hi LDN failed to stimulate T-cell activation. All 3 COVID-19 neutrophil populations suppressed stimulation of IFN-γ production, compared to HD NDN. We conclude that NDN and LDN from COVID-19 patients possess complementary functional capabilities that may act cooperatively to determine disease severity. We predict that global neutrophil responses that induce COVID-19 ARDS will vary depending on the proportion of neutrophil subsets.
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COVID-19 , Armadilhas Extracelulares , Armadilhas Extracelulares/metabolismo , Humanos , Neutrófilos/metabolismo , Explosão Respiratória , SARS-CoV-2RESUMO
Background: Lupus nephritis (LN) is a prevalent and severe complication of systemic lupus erythematosus (SLE). Non-invasive diagnostics are limited, and current therapies have inadequate response rates. Expression of the chemokine Interferon-γ-induced protein 10 (IP-10) is regulated by Interferon-γ signaling and NF-κB, and its molecular activity and enhanced urine concentrations are implicated in LN, but its utility as a diagnostic marker and association with demographic, clinical, or pathologic features is not defined. Methods: 38 LN patients and 11 patients with non-LN glomerular diseases (GD) with active disease were included. Eighteen of the LN patients had achieved remission at one follow-up during the study time. Serum and urine were obtained from these samples, and the IP-10 levels were measured. Results: Serum and urine IP-10 levels are significantly enhanced in LN patients with active disease as compared with normal individuals (serum average 179.7 pg/mL vs. 7.2 pg/mL, p < 0.0001; urine average 28.7 pg/mg vs. 1.6 pg/mg, p = 0.0019) and patients with other forms of glomerular disease (serum average 179.7 pg/mL vs. 84.9 pg/mL, p = 0.0176; urine average 28.7 pg/mg vs. 0.18 pg/mg, p = 0.0011). Urine IP-10 levels are significantly higher in patients with proliferative LN (PLN) than those with membranous LN (MLN) (average 32.8 pg/mg vs. 7.6 pg/mg, p = 0.0155). Urine IP-10 levels are also higher in MLN versus primary membranous nephropathy (MN) (average 7.6 pg/mg vs. 0.2 pg/mg, p = 0.0193). Importantly, serum IP-10 levels remain elevated during active LN and LN remission, but urine IP-10 levels are decreased from active LN to remission in 72% of our patients. Lastly, serum, but not urine IP-10 levels are significantly higher in African American than White American LN patients in active LN (average 227.8 pg/mL vs. 103.4 pg/mL, p = 0.0309) and during LN remission (average 254.6 pg/mL vs. 89.2 pg/mL, p = 0.0399). Conclusions: Our findings suggest that serum and urine IP-10 measurements provide promising tests for monitoring LN activity, differentiation between classifications of LN, and differentiation between LN and other forms of glomerular disease. We also conclude that further assessment of elevated IP-10 levels in the serum and urine of high-risk populations (i.e., African American) could be beneficial in determining why many of these patients have worse outcomes and are non-responsive to standard therapeutics.
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AIMS: Transforming growth factor-ß (TGF-ß) mediates fibrotic manifestations of diabetic nephropathy. We demonstrated proteasomal degradation of anti-fibrotic protein, nuclear factor-erythroid derived 2 (NF-E2), in TGF-ß treated human renal proximal tubule (HK-11) cells and in diabetic mouse kidneys. The current study examined the role of mitogen-activated protein kinase (MAPK) pathways in mediating NF-E2 proteasomal degradation and stimulating profibrotic signaling in HK-11 cells. MAIN METHODS: HK-11 cells were pretreated with vehicle or appropriate proteasome and MAPK inhibitors, MG132 (0.5 µM), SB203580 (1 µM), PD98059 (25 µM) and SP600125 (10 µM), respectively, followed by treatment with/without TGF-ß (10 ng/ml, 24 h). Cell lysates and kidney homogenates from FVB and OVE26 mice treated with/without MG132 were immunoblotted with appropriate antibodies. pUse vector and pUse-NF-E2 cDNA were transfected in HK-11 cells and effects of TGF-ß on JNK MAPK phosphorylation (pJNK) was examined. KEY FINDINGS: We demonstrated activation of p38, ERK, and JNK MAPK pathways in TGF-ß treated HK-11 cells. Dual p38 and ERK MAPK blockade prevented TGF-ß-induced pSer82Hsp27, fibronectin and connective tissue growth factor (CTGF) expression while preserving NF-E2 expression. Blockade of JNK MAPK inhibited TGF-ß-induced CTGF expression without preserving NF-E2 expression. MG132 treatment prevented TGF-ß-induced pJNK in HK-11 cells and in type 1 diabetic OVE26 mouse kidneys, demonstrating that TGF-ß- and diabetes-induced pJNK occurs downstream of proteasome activation. A direct role for NF-E2 in modulating pJNK activation was demonstrated by NF-E2 over-expression. SIGNIFICANCE: ERK and p38 MAPK promotes NF-E2 proteasomal degradation while proteasome activation promotes pJNK and profibrotic signaling in renal proximal tubule cells.
Assuntos
Túbulos Renais Proximais/metabolismo , Sistema de Sinalização das MAP Quinases/fisiologia , Subunidade p45 do Fator de Transcrição NF-E2/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/antagonistas & inibidores , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Animais , Antracenos/farmacologia , Linhagem Celular Transformada , Inibidores de Cisteína Proteinase/farmacologia , Feminino , Fibrose , Humanos , Túbulos Renais Proximais/efeitos dos fármacos , Túbulos Renais Proximais/patologia , Leupeptinas/farmacologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Camundongos , Camundongos TransgênicosRESUMO
Diabetic cardiomyopathy (DCM) is a serious diabetic complication that lacks effective preventive or therapeutic approaches. Wild-type and Klf15 knockout (Klf15-KO) mice were fed with either high fat diet (HFD, 60% kcal from fat) or normal diet (ND, 10% kcal from fat) for 3 months and then injected with streptozotocin or vehicle, to induce type 2 diabetes (T2D). All T2D and age-matched control mice were treated with or without SDF-1ß at 5 mg/kg body-weight twice a week and also continually received HFD or ND for 3 months. At the end of 6-month study, after cardiac functions were measured, mice were euthanized to collect heart tissue. For in vitro mechanistic study, H9c2 cells were exposed to palmitate to mimic in vivo condition of T2D. SDF-1ß prevented T2D-induced cardiac dysfunction and fibrosis and T2D-down-regulated KLF15 expression in wild-type diabetic heart tissue. However, the preventive effects of SDF-1ß on both KLF15 expression and fibrosis was abolished, with partial cardiac protection in Klf15-KO/T2D mice. These results demonstrate partial KLF15-dependence for SDF-1ß's cardiac fibrotic protection from T2D, but not on SDF-1ß's protective effects on T2D-induced cardiac dysfunction. Further study showed that SDF-1ß inhibited palmitate-induced cardiomyocyte fibrosis through its receptor CXCR7-mediated activation of p38ß MAPK signaling pathway.
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Quimiocina CXCL12/uso terapêutico , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Cardiomiopatias Diabéticas/tratamento farmacológico , Fatores de Transcrição Kruppel-Like/deficiência , Animais , Linhagem Celular , Quimiocina CXCL12/farmacologia , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Cardiomiopatias Diabéticas/metabolismo , Fibrose/tratamento farmacológico , Fibrose/metabolismo , Fatores de Transcrição Kruppel-Like/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , RatosRESUMO
Transcription factor Krüppel-like factor 5 (KLF5) is a member of the Krüppel-like factors' (KLFs) family. KLF5 regulates a number of cellular functions, such as apoptosis, proliferation and differentiation. Therefore, KLF5 can play a role in many diseases, including, cancer, cardiovascular disease and gastrointestinal disorders. An important role for KLF5 in the kidney was recently reported, such that KLF5 regulated podocyte apoptosis, renal cell proliferation, tubulointerstitial inflammation and renal fibrosis. In this review, we have summarized the available information in the literature with a brief description on how transcriptional, post-transcriptional and post-translational modifications of KLF5 modulate its function in a variety of organs including the kidney with a focus of its importance on the pathogenesis of various kidney diseases. Furthermore, we also have outlined the current and possible mechanisms of KLF5 activation in kidney diseases. These studies suggest a need for more systemic investigations, particularly for generation of animal models with renal cell-specific deletion or overexpression of KLF5 gene to examine direct contributions of KLF5 to various kidney diseases. This will promote further experimentation in the development of therapies to prevent or treat various kidney diseases.
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Suscetibilidade a Doenças , Nefropatias/etiologia , Nefropatias/metabolismo , Fatores de Transcrição Kruppel-Like/genética , Fatores de Transcrição Kruppel-Like/metabolismo , Animais , Apoptose , Biomarcadores , Proliferação de Células , Modelos Animais de Doenças , Fibrose , Regulação da Expressão Gênica , Redes Reguladoras de Genes , Humanos , Nefropatias/patologia , Processamento de Proteína Pós-Traducional , Processamento Pós-Transcricional do RNA , Transdução de SinaisRESUMO
AIMS: This study aimed to examine the anti-fibrotic role of Nuclear Factor-Erythroid derived 2 (NF-E2) in human renal tubule (HK-11) cells and in type 1 and type 2 diabetic (T1D, T2D) mouse kidneys. MAIN METHODS: Anti-fibrotic effects of NF-E2 were examined in transforming growth factor-ß (TGF-ß) treated HK-11 cells by over-expressing/silencing NF-E2 expression and determining its effects on profibrotic signaling. NF-E2 proteasomal degradation was confirmed by proteasome inhibition in HK-11 cells and diabetic mice. Clinical relevance of changes in NF-E2 expression to fibrotic changes in the kidney were assessed in T1D and T2D mouse kidneys. KEY FINDINGS: NF-E2 expression was significantly decreased in TGF-ß treated HK-11 cells and in kidneys of diabetic mice with concurrent increase in expression of fibrotic proteins. TGF-ß treatment of HK-11 cells did not inhibit NF-E2 mRNA expression, suggesting that the post-translational changes may contribute to NF-E2 protein degradation. The down-regulation of NF-E2 expression was attributed to its proteasomal degradation, as TGF-ß- and diabetes-induced NF-E2 down regulation was prevented by proteasome inhibitor treatment. In HK-11 cells TGF-ß treatment decreased E-cadherin expression and induced pSer82Hsp27/NF-E2 association, likely to promote NF-E2 degradation, as Hsp27 can target proteins to the proteasome. A critical role for NF-E2 in regulation of renal fibrosis was demonstrated as over-expression of NF-E2 or silencing NF-E2 expression, decreased or increased profibrotic proteins in TGF-ß-treated HK-11 cells, respectively. SIGNIFICANCE: NF-E2, a novel anti-fibrotic protein, is down-regulated in diabetic kidneys. Preserving/inducing NF-E2 expression in diabetic kidneys may provide a therapeutic potential to combat DN.
Assuntos
Diabetes Mellitus Experimental/metabolismo , Fibrose/fisiopatologia , Subunidade p45 do Fator de Transcrição NF-E2/fisiologia , Animais , Caderinas/biossíntese , Células Cultivadas , Inibidores de Cisteína Proteinase/farmacologia , Diabetes Mellitus Experimental/genética , Regulação para Baixo , Fibrose/metabolismo , Técnicas de Silenciamento de Genes , Proteínas de Choque Térmico HSP27/metabolismo , Humanos , Rim/metabolismo , Túbulos Renais/metabolismo , Leupeptinas/farmacologia , Masculino , Camundongos , Camundongos Transgênicos , Subunidade p45 do Fator de Transcrição NF-E2/biossíntese , Subunidade p45 do Fator de Transcrição NF-E2/genética , Ligação Proteica/efeitos dos fármacos , Transdução de Sinais/fisiologia , Fator de Crescimento Transformador beta/efeitos adversos , Fator de Crescimento Transformador beta/antagonistas & inibidoresAssuntos
Monócitos/imunologia , Neutrófilos/imunologia , Sepse/imunologia , Receptor 4 Toll-Like/metabolismo , Apoptose , Sobrevivência Celular , Células Cultivadas , Celulase , Citocinas/metabolismo , Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , Humanos , Ativação de NeutrófiloRESUMO
Although there is an increasing understanding of the signaling pathways that promote cardiac hypertrophy, negative regulatory factors of this process have received less attention. Increasing evidence indicates that Krüppel-like factor 15 (KLF15) plays an important role in maintaining cardiac function by controlling the transcriptional pathways that regulating cardiac metabolism. Recent studies have also revealed a vital role for KLF15 as an inhibitor of pathological cardiac hypertrophy and fibrosis via its effects on factors such as myocyte enhancer factor 2 (MEF2), GATA-binding protein 4 (GATA4), transforming growth factor-ß (TGF-ß), and myocardin. KLF15 may therefore be an effective therapeutic target for the treatment of heart failure and other cardiovascular diseases. In this review, we focus on the physiological and pathophysiological roles of KLF15 in the heart and the potential mechanisms through which KLF15 is regulated in various cardiac diseases.
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Doenças Cardiovasculares/metabolismo , Doenças Cardiovasculares/terapia , Fatores de Transcrição Kruppel-Like/metabolismo , Miocárdio/metabolismo , Animais , Homeostase , Humanos , PublicaçõesRESUMO
Noncanonical roles for caspase-3 are emerging in the fields of cancer and developmental biology. However, little is known of nonapoptotic functions of caspase-3 in most cell types. We have recently demonstrated a disassociation between caspase-3 activation and execution of apoptosis with accompanying cytoplasmic caspase-3 sequestration and preserved endothelial barrier function. Therefore, we tested the hypothesis that nonapoptotic caspase-3 activation promotes endothelial barrier integrity. Human lung microvascular endothelial cells were exposed to thrombin, a nonapoptotic stimulus, and endothelial barrier function was assessed using electric cell-substrate impedance sensing. Actin cytoskeletal rearrangement and paracellular gap formation were assessed using phalloidin staining. Cell stiffness was evaluated using magnetic twisting cytometry. In addition, cell lysates were harvested for protein analyses. Caspase-3 was inhibited pharmacologically with pan-caspase and a caspase-3-specific inhibitor. Molecular inhibition of caspase-3 was achieved using RNA interference. Cells exposed to thrombin exhibited a cytoplasmic activation of caspase-3 with transient and nonapoptotic decrease in endothelial barrier function as measured by a drop in electrical resistance followed by a rapid recovery. Inhibition of caspases led to a more pronounced and rapid drop in thrombin-induced endothelial barrier function, accompanied by increased endothelial cell stiffness and paracellular gaps. Caspase-3-specific inhibition and caspase-3 knockdown both resulted in more pronounced thrombin-induced endothelial barrier disruption. Taken together, our results suggest cytoplasmic caspase-3 has nonapoptotic functions in human endothelium and can promote endothelial barrier integrity.
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Caspase 3/metabolismo , Células Endoteliais/citologia , Endotélio Vascular/metabolismo , Mucosa Respiratória/citologia , Junções Íntimas/efeitos dos fármacos , Citoesqueleto de Actina/fisiologia , Permeabilidade Capilar/efeitos dos fármacos , Caspase 3/genética , Células Cultivadas , Impedância Elétrica , Endotélio Vascular/citologia , Humanos , Pulmão/citologia , Interferência de RNA , RNA Interferente Pequeno/genética , Trombina/farmacologiaRESUMO
Diabetic nephropathy (DN) is one of the most serious long-term complications of type 2 diabetes (T2D). 4-O-methylhonokiol (MH) is one of the biologically active ingredients extracted from the Magnolia stem bark. In this study, we aim to elucidate whether treatment with MH can ameliorate or slow-down progression of DN in a T2D murine model and, if so, whether the protective response of MH correlates with AMPK-associated anti-oxidant and anti-inflammatory effects. To induce T2D, mice were fed normal diet (ND) or high fat diet (HFD) for 3â¯months to induce insulin resistance, followed by an intraperitoneal injection of STZ to induce hyperglycemia. Both T2D and control mice received gavage containing vehicle or MH once diabetes onset for 3â¯months. Once completing 3-month MH treatment, five mice from each group were sacrificed as 3â¯month time-point. The rest mice in each group were sacrificed 3â¯months later as 6â¯month time-point. In T2D mice, the typical DN symptoms were induced as expected, reflected by increased proteinuria, renal lipid accumulation and lipotoxic effects inducing oxidative stress, and inflammatory reactions, and final fibrosis. However, these typical DN changes were significantly prevented by MH treatment for 3â¯months and even at 3â¯months post-MH withdrawal. Mechanistically, MH renal-protection from DN may be related to lipid metabolic improvement and oxidative stress attenuation along with increases in AMPK/PGC-1α/CPT1B-mediated fatty acid oxidation and Nrf2/SOD2-mediated anti-oxidative stress. Results showed the preventive effect of MH on the renal oxidative stress and inflammation in DN.
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Proteínas Quinases Ativadas por AMP/metabolismo , Compostos de Bifenilo/administração & dosagem , Nefropatias Diabéticas/prevenção & controle , Ácidos Graxos/metabolismo , Lignanas/administração & dosagem , Fator 2 Relacionado a NF-E2/fisiologia , Estresse Oxidativo/efeitos dos fármacos , Animais , Anti-Inflamatórios/administração & dosagem , Antioxidantes/administração & dosagem , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Tipo 2/complicações , Nefropatias Diabéticas/patologia , Dieta Hiperlipídica , Ativação Enzimática/efeitos dos fármacos , Resistência à Insulina , Rim/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Oxirredução , FitoterapiaRESUMO
Na+/H+ exchange regulatory cofactor (NHERF)-1, a scaffolding protein, anchors multiple membrane proteins in renal proximal tubules. Cultured proximal tubule cells deficient in Nherf1 and proximal tubules from Nherf1-deficient mice exhibit aberrant trafficking. Nherf1-deficient cells also exhibit an altered transcription pattern and worse survival. These observations suggest that NHERF1 loss increases susceptibility to acute kidney injury (AKI). Male and female wild-type C57BL/6J and Nherf1 knockout mice were treated with saline or cisplatin (20 mg/kg dose i.p.) to induce AKI and were euthanized after 72 hours. Blood and urine were collected for assessments of blood urea nitrogen and neutrophil gelatinase-associated lipocalin, respectively. Kidneys were harvested for histology (hematoxylin and eosin, periodic acid-Schiff) and terminal deoxynucleotidyl transferase dUTP nick end labeling assay, Kim1 mRNA assessment, and Western blot analysis for cleaved caspase 3. Cisplatin treatment was associated with significantly greater severity of AKI in knockout compared with wild-type mice, as demonstrated by semiquantitative injury score (2.8 versus 1.89, P < 0.001), blood urea nitrogen (151.8 ± 17.2 mg/dL versus 97.8 ± 10.1 mg/dL, P < 0.05), and neutrophil gelatinase-associated lipocalin urine protein (55.6 ± 21.3 µg/mL versus 2.7 ± 0.53 µg/mL, P < 0.05). Apoptosis markers were significantly increased in cisplatin-treated Nherf1 knockout and wild-type mice compared to respective controls. These data suggest that NHERF1 loss increases susceptibility to AKI.
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Injúria Renal Aguda/metabolismo , Cisplatino/efeitos adversos , Fosfoproteínas/metabolismo , Trocadores de Sódio-Hidrogênio/metabolismo , Injúria Renal Aguda/induzido quimicamente , Injúria Renal Aguda/genética , Injúria Renal Aguda/patologia , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Caspase 3/metabolismo , Cisplatino/farmacologia , Suscetibilidade a Doenças , Feminino , Receptor Celular 1 do Vírus da Hepatite A/metabolismo , Lipocalina-2/metabolismo , Masculino , Camundongos , Camundongos Knockout , Fosfoproteínas/genética , Trocadores de Sódio-Hidrogênio/genéticaRESUMO
Dysregulated KrÏppel-like factor (KLF) gene expression appears in many disease-associated pathologies. In this review, we discuss physiological functions of KLFs in the kidney with a focus on potential pharmacological modulation/therapeutic applications of these KLF proteins. KLF2 is critical to maintaining endothelial barrier integrity and preventing gap formations and in prevention of glomerular endothelial cell and podocyte damage in diabetic mice. KLF4 is renoprotective in the setting of AKI and is a critical regulator of proteinuria in mice and humans. KLF6 expression in podocytes preserves mitochondrial function and prevents podocyte apoptosis, while KLF5 expression prevents podocyte apoptosis by blockade of ERK/p38 MAPK pathways. KLF15 is a critical regulator of podocyte differentiation and is protective against podocyte injury. Loss of KLF4 and KLF15 promotes renal fibrosis, while fibrotic kidneys have increased KLF5 and KLF6 expression. For therapeutic modulation of KLFs, continued screening of small molecules will promote drug discoveries targeting KLF proteins.
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Nefropatias/etiologia , Nefropatias/metabolismo , Rim/metabolismo , Fatores de Transcrição Kruppel-Like/genética , Fatores de Transcrição Kruppel-Like/metabolismo , Animais , Suscetibilidade a Doenças , Endotélio Vascular/metabolismo , Células Epiteliais/metabolismo , Fibrose , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Rim/efeitos dos fármacos , Rim/patologia , Nefropatias/tratamento farmacológico , Nefropatias/patologia , Túbulos Renais/metabolismo , Fator 4 Semelhante a Kruppel , Fatores de Transcrição Kruppel-Like/química , Podócitos/metabolismo , Transdução de Sinais/efeitos dos fármacos , Relação Estrutura-AtividadeRESUMO
Hyperglycemia-induced renal fibrosis causes end-stage renal disease. Clopidogrel, a platelet inhibitor, is often administered to decrease cardiovascular events in diabetic patients. We investigated whether clopidogrel can reduce diabetes-induced renal fibrosis in a streptozotocin-induced type 1 diabetes murine model and fibronectin involvement in this protective response. Diabetic and age-matched controls were sacrificed three months after the onset of diabetes, and additional controls and diabetic animals were further treated with clopidogrel or vehicle for three months. Diabetes induced renal morphological changes and fibrosis after three months. Clopidogrel, administered during the last three months, significantly decreased blood glucose, collagen and fibronectin expression compared to vehicle-treated diabetic mice. Diabetes increased TGF-ß expression, inducing fibrosis via Smad-independent pathways, MAP kinases, and Akt activation at three months but returned to baseline at six months, whereas the expression of fibronectin and collagen remained elevated. Our results suggest that activation of TGF-ß, CTGF, and MAP kinases are early profibrotic signaling events, resulting in significant fibronectin accumulation at the early time point and returning to baseline at a later time point. Akt activation at the three-month time point may serve as an adaptive response in T1D. Mechanisms of clopidogrel therapeutic effect on the diabetic kidney remain to be investigated as this clinically approved compound could provide novel approaches to prevent diabetes-induced renal disease, therefore improving patients' survival.
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Clopidogrel/uso terapêutico , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/tratamento farmacológico , Fibronectinas/metabolismo , Fibrose/tratamento farmacológico , Fibrose/etiologia , Nefropatias/tratamento farmacológico , Animais , Coagulação Sanguínea/efeitos dos fármacos , Western Blotting , Clopidogrel/farmacologia , Fibrose/metabolismo , Imuno-Histoquímica , Rim/efeitos dos fármacos , Rim/patologia , Nefropatias/etiologia , Nefropatias/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Antagonistas do Receptor Purinérgico P2Y/farmacologia , Antagonistas do Receptor Purinérgico P2Y/uso terapêuticoRESUMO
We examined the association of urine inositol 1,3,4,5,6-pentakisphosphate 2-kinase (IPP2K) with the presence and progression of diabetic kidney disease (DKD) lesions. Urine IPP2K was measured at baseline by quantitative liquid chromatography-mass spectrometry in 215 participants from the Renin-Angiotensin System Study who had type 1 diabetes and were normoalbuminuric and normotensive with normal or increased glomerular filtration rate (GFR). Urine IPP2K was detectable in 166 participants. Participants with IPP2K below the limit of quantification (LOQ) were assigned concentrations of LOQ/â2. All concentrations were then standardized to urine creatinine (Cr) concentration. Kidney morphometric data were available from biopsies at baseline and after 5 yr. Relationships of IPP2K/Cr with morphometric variables were assessed by linear regression after adjustment for age, sex, diabetes duration, hemoglobin A1c, mean arterial pressure, treatment assignment, and, for longitudinal analyses, baseline structure. Baseline mean age was 29.7 yr, mean diabetes duration 11.2 yr, median albumin excretion rate 5.0 µg/min, and mean iohexol GFR 129 ml·min-1·1.73m-2. Higher IPP2K/Cr was associated with higher baseline peripheral glomerular total filtration surface density [Sv(PGBM/glom), tertile 3 vs. tertile 1 ß = 0.527, P = 0.011] and with greater preservation of Sv(PGBM/glom) after 5 yr ( tertile 3 vs. tertile 1 ß = 0.317, P = 0.013). Smaller increases in mesangial fractional volume ( tertile 3 vs. tertile 1 ß = -0.578, P = 0.018) were observed after 5 yr in men with higher urine IPP2K/Cr concentrations. Higher urine IPP2K/Cr is associated with less severe kidney lesions at baseline and with preservation of kidney structure over 5 yr in individuals with type 1 diabetes and no clinical evidence of DKD at baseline.
Assuntos
Diabetes Mellitus Tipo 1/complicações , Nefropatias Diabéticas/patologia , Nefropatias Diabéticas/urina , Rim/patologia , Fosfotransferases (Aceptor do Grupo Álcool)/urina , Adulto , Biomarcadores/urina , Biópsia , Cromatografia Líquida de Alta Pressão , Cromatografia de Fase Reversa , Ensaios Clínicos como Assunto , Diabetes Mellitus Tipo 1/diagnóstico , Nefropatias Diabéticas/enzimologia , Nefropatias Diabéticas/etiologia , Progressão da Doença , Feminino , Humanos , Masculino , Espectrometria de Massas , Estudos Multicêntricos como Assunto , Fatores de Tempo , Regulação para Cima , Adulto JovemRESUMO
Hypoxia is a primary factor in many pathological conditions. Hypoxic cell death is commonly attributed to metabolic failure and oxidative injury. cAMP-dependent protein kinase A (PKA) is activated in hypoxia and regulates multiple enzymes of the mitochondrial electron transport chain, thus may be implicated in cellular energy depletion and hypoxia-induced cell death. Wild type (WT) PC-12 cells and PKA activity-deficient 123.7 PC-12 cells were exposed to 3, 6, 12 and 24h hypoxia (0.1% or 5% O2). Hypoxia, at 24h 0.1% O2, induced cell death and increased reactive oxygen species (ROS) in WT PC-12 cells. Despite lower ATP levels in normoxic 123.7 cells than in WT cells, hypoxia only decreased ATP levels in WT cells. However, menadione-induced oxidative stress similarly affected both cell types. While mitochondrial COX IV expression remained consistently higher in 123.7 cells, hypoxia decreased COX IV expression in both cell types. N-acetyl cysteine antioxidant treatment blocked hypoxia-induced WT cell death without preventing ATP depletion. Transient PKA catα expression in 123.7 cells partially restored hypoxia-induced ROS but did not alter ATP levels or COX IV expression. We conclude that PKA signaling contributes to hypoxic injury, by regulating oxidative stress rather than by depleting ATP levels. Therapeutic strategies targeting PKA signaling may improve cellular adaptation and recovery in hypoxic pathologies.
Assuntos
Neoplasias das Glândulas Suprarrenais/enzimologia , Subunidades Catalíticas da Proteína Quinase Dependente de AMP Cíclico/metabolismo , Neurônios/enzimologia , Estresse Oxidativo , Feocromocitoma/enzimologia , Espécies Reativas de Oxigênio/metabolismo , Hipóxia Tumoral , Trifosfato de Adenosina/metabolismo , Neoplasias das Glândulas Suprarrenais/genética , Neoplasias das Glândulas Suprarrenais/patologia , Animais , Subunidades Catalíticas da Proteína Quinase Dependente de AMP Cíclico/genética , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Metabolismo Energético , Neurônios/efeitos dos fármacos , Neurônios/patologia , Estresse Oxidativo/efeitos dos fármacos , Células PC12 , Feocromocitoma/genética , Feocromocitoma/patologia , Ratos , Transdução de Sinais , Fatores de Tempo , Transfecção , Vitamina K 3/farmacologiaRESUMO
BACKGROUND: A targeted analysis of the 50kDa C-terminal fragment of insulin-response element binding protein-1 (IRE-BP1) activation of target genes through the insulin receptor substrate receptor/PI-3 kinase/Akt pathway has been demonstrated for the insulin growth factor-1 receptor. The broader effects of 50kDa C-terminal IRE-BP1 fragment over-expression on protein abundance in pancreatic islet beta cells have not been determined. RESULTS: Liquid-chromatography coupled to tandem mass spectrometry (LC-MS/MS) analyses of replicate lysates of pancreatic islets isolated from background strain animals and transgenic animals, overexpressing IRE-BP1 in pancreatic islet beta cells, demonstrated statistically significant increases in the expression of proteins involved in protein synthesis, endoplasmic reticulum (ER) stress and scaffolding proteins important for protein kinase C signaling; some of which were confirmed by immunoblot analyses. Bioinformatic analysis of protein expression network patterns suggested IRE-BP1 over-expression leads to protein expression patterns indicative of activation of functional protein networks utilized for protein post-translational modification, protein folding, and protein synthesis. Co-immunoprecipitation experiments demonstrate a novel interaction between two differentially regulated proteins receptor for activated protein kinase C (RACK1) and translationally controlled tumor protein (TCTP). CONCLUSIONS: Proteomic analysis of IRE-BP1 over-expression in pancreatic islet beta cells suggest IRE-BP1 (a) directly or indirectly through establishing hyperglycemia results in increased expression of ribosomal proteins and markers of ER stress and (b) leads to the enhanced and previously un-described interaction of RACK1 and TCTP. SIGNIFICANCE: This study identified C-terminal 50kDa domain of IRE-BP1 over-expression results in increased markers of ER-stress and a novel interaction between the scaffolding proteins RACK1 and TCTP.
Assuntos
Biomarcadores Tumorais/metabolismo , Biomarcadores/metabolismo , Glucose/metabolismo , Células Secretoras de Insulina/metabolismo , Proteína 1 Reguladora do Ferro/metabolismo , Ilhotas Pancreáticas/metabolismo , Neuropeptídeos/metabolismo , Animais , Estresse do Retículo Endoplasmático/fisiologia , Hiperglicemia , Insulina/metabolismo , Camundongos , Proteína Quinase C/metabolismo , Processamento de Proteína Pós-Traducional/fisiologia , Proteômica/métodos , Receptores de Quinase C Ativada , Elementos de Resposta/fisiologia , Proteína Tumoral 1 Controlada por TraduçãoRESUMO
Diabetes is strongly associated with systemic inflammation and oxidative stress, but its effect on pulmonary vascular disease and lung function has often been disregarded. Several studies identified restrictive lung disease and fibrotic changes in diabetic patients and in animal models of diabetes. While microvascular dysfunction is a well-known complication of diabetes, the mechanisms leading to diabetes-induced lung injury have largely been disregarded. We described the potential involvement of diabetes-induced platelet-endothelial interactions in perpetuating vascular inflammation and oxidative injury leading to fibrotic changes in the lung. Changes in nitric oxide synthase (NOS) activation and decreased NO bioavailability in the diabetic lung increase platelet activation and vascular injury and may account for platelet hyperreactivity reported in diabetic patients. Additionally, the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway has been reported to mediate pancreatic islet damage, and is implicated in the onset of diabetes, inflammation and vascular injury. Many growth factors and diabetes-induced agonists act via the JAK/STAT pathway. Other studies reported the contribution of the JAK/STAT pathway to the regulation of the pulmonary fibrotic process but the role of this pathway in the development of diabetic lung fibrosis has not been considered. These observations may open new therapeutic perspectives for modulating multiple pathways to mitigate diabetes onset or its pulmonary consequences.