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1.
Cell Commun Signal ; 22(1): 220, 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38589923

RESUMO

Endosomal single-stranded RNA-sensing Toll-like receptor-7/8 (TLR7/8) plays a pivotal role in inflammation and immune responses and autoimmune diseases. However, the mechanisms underlying the initiation of the TLR7/8-mediated autoimmune signaling remain to be fully elucidated. Here, we demonstrate that miR-574-5p is aberrantly upregulated in tissues of lupus prone mice and in the plasma of lupus patients, with its expression levels correlating with the disease activity. miR-574-5p binds to and activates human hTLR8 or its murine ortholog mTlr7 to elicit a series of MyD88-dependent immune and inflammatory responses. These responses include the overproduction of cytokines and interferons, the activation of STAT1 signaling and B lymphocytes, and the production of autoantigens. In a transgenic mouse model, the induction of miR-574-5p overexpression is associated with increased secretion of antinuclear and anti-dsDNA antibodies, increased IgG and C3 deposit in the kidney, elevated expression of inflammatory genes in the spleen. In lupus-prone mice, lentivirus-mediated silencing of miR-574-5p significantly ameliorates major symptoms associated with lupus and lupus nephritis. Collectively, these results suggest that the miR-574-5p-hTLR8/mTlr7 signaling is an important axis of immune and inflammatory responses, contributing significantly to the development of lupus and lupus nephritis.


Assuntos
Nefrite Lúpica , MicroRNAs , Humanos , Camundongos , Animais , Nefrite Lúpica/genética , Receptor 7 Toll-Like/genética , Receptor 7 Toll-Like/metabolismo , Receptor 8 Toll-Like/genética , Receptor 8 Toll-Like/metabolismo , Rim/metabolismo , Camundongos Transgênicos , MicroRNAs/genética
2.
J Surg Case Rep ; 2022(7): rjac356, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35919700

RESUMO

Goblet cell carcinoid (GCC) tumor is a rare appendiceal carcinoma that has had several names throughout its history. Often found incidentally on pathology following an appendectomy, treatment includes a right hemicolectomy and possible adjuvant chemotherapy. Survival rate has been shown to be correlated with the histological features. Here, we report a 45-year-old African American male who presented with signs and symptoms consistent with acute appendicitis, but was ultimately diagnosed with GCC. After undergoing a right hemicolectomy, he continues to undergo long-term surveillance with his oncologist. Due to the rarity of this tumor, we describe the history of GCC and our recommendations for surgical and long-term management.

3.
J Surg Case Rep ; 2022(5): rjac188, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35665387

RESUMO

Traumatic abdominal wall hernia is defined as protrusion of bowel or an abdominal organ through a disruption of musculature and fascia following a severe blunt trauma. We report a case of a patient who had a delayed presentation of a traumatic, superiorly located paralumbar hernia months after the initial admission.

4.
J Surg Case Rep ; 2022(6): rjac273, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35702262

RESUMO

Herpes simplex virus is an infection that can result in a variety of symptoms ranging from blistering or ulcers to severe, systemic manifestations. We report a case of patient who underwent elective spinal surgery and developed invasive herpes as well as candidiasis postoperatively without any direct evidence of immunosuppression.

5.
Front Pharmacol ; 12: 784231, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34880765

RESUMO

The prevalence of diabetes mellitus has been increasing for decades worldwide. To develop safe and potent therapeutics, animal models contribute a lot to the studies of the mechanisms underlying its pathogenesis. Dietary induction using is a well-accepted protocol in generating insulin resistance and diabetes models. In the present study, we reported the multi-omics profiling of the liver and sera from both peripheral blood and hepatic portal vein blood from Macaca fascicularis that spontaneously developed Type-2 diabetes mellitus with a chow diet (sDM). The other two groups of the monkeys fed with chow diet and high-fat high-sugar (HFHS) diet, respectively, were included for comparison. Analyses of various omics datasets revealed the alterations of high consistency. Between the sDM and HFHS monkeys, both the similar and unique alterations in the lipid metabolism have been demonstrated from metabolomic, transcriptomic, and proteomic data repeatedly. The comparison of the proteome and transcriptome confirmed the involvement of fatty acid binding protein 4 (FABP4) in the diet-induced pathogenesis of diabetes in macaques. Furthermore, the commonly changed genes between spontaneous diabetes and HFHS diet-induced prediabetes suggested that the alterations in the intra- and extracellular structural proteins and cell migration in the liver might mediate the HFHS diet induction of diabetes mellitus.

6.
J Biol Chem ; 294(40): 14745-14756, 2019 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-31409643

RESUMO

The glucose-responsive transcription factor carbohydrate response element-binding protein (ChREBP) critically promotes aerobic glycolysis and cell proliferation in colorectal cancer cells. It has been reported that ubiquitination may be important in the regulation of ChREBP protein levels and activities. However, the ChREBP-specific E3 ligase and molecular mechanism of ChREBP ubiquitination remains unclear. Using database exploration and expression analysis, we found here that levels of the E3 ligase SMURF2 (Smad-ubiquitination regulatory factor 2) negatively correlate with those of ChREBP in cancer tissues and cell lines. We observed that SMURF2 interacts with ChREBP and promotes ChREBP ubiquitination and degradation via the proteasome pathway. Interestingly, ectopic SMURF2 expression not only decreased ChREBP levels but also reduced aerobic glycolysis, increased oxygen consumption, and decreased cell proliferation in colorectal cancer cells. Moreover, SMURF2 knockdown increased aerobic glycolysis, decreased oxygen consumption, and enhanced cell proliferation in these cells, mostly because of increased ChREBP accumulation. Furthermore, we identified Ser/Thr kinase AKT as an upstream suppressor of SMURF2 that protects ChREBP from ubiquitin-mediated degradation. Taken together, our results indicate that SMURF2 reduces aerobic glycolysis and cell proliferation by promoting ChREBP ubiquitination and degradation via the proteasome pathway in colorectal cancer cells. We conclude that the SMURF2-ChREBP interaction might represent a potential target for managing colorectal cancer.


Assuntos
Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/genética , Neoplasias Colorretais/genética , Glicólise/genética , Ubiquitina-Proteína Ligases/genética , Aerobiose/genética , Animais , Proliferação de Células/genética , Neoplasias Colorretais/patologia , Regulação Neoplásica da Expressão Gênica/genética , Células HCT116 , Xenoenxertos , Humanos , Camundongos , Proteólise , Ubiquitinação/genética
7.
Int J Biol Sci ; 13(1): 122-134, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28123352

RESUMO

MicroRNAs are a novel class of gene regulators that function as oncogenes or tumor suppressors. In our current study, we investigated the role of miR-15a-3p and miR-16-1-3p in the regulation of Twist1 expression and EMT process. Our bioinformatics analysis suggested that on the 3' UTR of Twist1, there are two conserved miRNA recognition sites for miR-15a-3p and miR-16-1-3p respectively. Interestingly, overexpression of miR-15a-3p and miR-16-1-3p significantly suppressed the activity of luciferase reporter containing Twist1-3' UTR, reduced mRNA and protein level of EMT related genes such as TWIST1, N-cadherin, α-SMA and Fibronectin, and repressed MMP9 and MMP2 activity, as well as cell migration and invasion. Conversely, inhibition of miR-15a-3p and miR-16-1-3p significantly increased TWIST1, N-cadherin, α-SMA and Fibronectin protein expression. In addition, Twist1 co-transfection significantly ameliorated the loss of cell migration and invasion. Moreover, overexpression of miR-15a-3p and miR-16-1-3p dramatically suppressed the ability of BGC823 cells to form colonies in vitro and develop tumors in vivo in nude mice. Finally, qPCR and Western blot analysis showed that miR-15a-3p and miR-16-1-3p were significantly reduced in clinical gastric cancer tissue, whereas Twist1 mRNA and protein were significantly up-regulated, suggesting that this aberrant down-regulation of miR-15a-3p and miR-16-1-3p might be associated with the abnormal regulation of Twist1 and the EMT process in gastric cancer development. Our results help to elucidate a novel and important mechanism for the regulation of Twist1 in the development of cancer.


Assuntos
MicroRNAs/metabolismo , Neoplasias Gástricas/metabolismo , Proteína 1 Relacionada a Twist/metabolismo , Animais , Linhagem Celular Tumoral , Movimento Celular/genética , Movimento Celular/fisiologia , Regulação Neoplásica da Expressão Gênica/genética , Regulação Neoplásica da Expressão Gênica/fisiologia , Humanos , Camundongos , Camundongos Nus , MicroRNAs/genética , Invasividade Neoplásica/genética , Neoplasias Gástricas/genética , Neoplasias Gástricas/patologia , Proteína 1 Relacionada a Twist/genética
8.
Nanoscale ; 8(44): 18740-18750, 2016 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-27790650

RESUMO

Many of the neurodegenerative disorders such as Huntington's disease (HD) are caused by the accumulation of intracytoplasmic aggregate-prone proteins. These toxic protein aggregates are mainly degraded by autophagy, thus elevating the autophagy level to enhance the degradation of these proteins representing an emerging viable approach for the treatment of neurodegenerative diseases. In this report we showed that graphene oxide (GO), an engineered nanomaterial with enormous potential in biomedical applications, effectively enhanced the clearance of mutant huntingtin (Htt), the aggregate-prone protein underlying the pathogenesis of HD. This enhancing effect of GO was autophagy-mediated, as blocking autophagy by chemical inhibitors at either the autophagosome formation stage or the autophagosome-lysosome fusion stage, or more specifically by knocking-down an essential autophagy gene, led to a significant reduction in the ability of GO to elicit Htt degradation. Interestingly, the autophagy induced by GO had the normal capacity to degrade its cargo including LC3-II and Htt, but not p62/SQSTM1 (p62), and was dependent on the activation of class III phosphatidylinositol 3-kinase (PtdIns3K) and MEK/ERK1/2 signaling pathways, without mTOR involvement. GO also increased ubiquitination of Htt, an event necessary for Htt's clearance. Furthermore, ubiquitinated huntingtin protein preferentially binds to GO, and abundant GO was found in autophagosomes and autolysosomes, thus raising the possibility that GO may directly deliver the bound protein to autophagosomes for degradation. Our results revealed a novel biological function of GO and may have implications for developing nanomaterial-based therapeutics for neurodegenerative diseases.

9.
Mol Cell ; 62(3): 359-370, 2016 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-27153534

RESUMO

Metabolic reprogramming is fundamental to biological homeostasis, enabling cells to adjust metabolic routes after sensing altered availability of fuels and growth factors. ULK1 and ULK2 represent key integrators that relay metabolic stress signals to the autophagy machinery. Here, we demonstrate that, during deprivation of amino acid and growth factors, ULK1/2 directly phosphorylate key glycolytic enzymes including hexokinase (HK), phosphofructokinase 1 (PFK1), enolase 1 (ENO1), and the gluconeogenic enzyme fructose-1,6-bisphosphatase (FBP1). Phosphorylation of these enzymes leads to enhanced HK activity to sustain glucose uptake but reduced activity of FBP1 to block the gluconeogenic route and reduced activity of PFK1 and ENO1 to moderate drop of glucose-6-phosphate and to repartition more carbon flux to pentose phosphate pathway (PPP), maintaining cellular energy and redox homeostasis at cellular and organismal levels. These results identify ULK1/2 as a bifurcate-signaling node that sustains glucose metabolic fluxes besides initiation of autophagy in response to nutritional deprivation.


Assuntos
Proteína Homóloga à Proteína-1 Relacionada à Autofagia/metabolismo , Autofagia , Glucose/metabolismo , Glicólise , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Via de Pentose Fosfato , Proteínas Serina-Treonina Quinases/metabolismo , Estresse Fisiológico , Aminoácidos/deficiência , Aminoácidos/metabolismo , Animais , Proteína Homóloga à Proteína-1 Relacionada à Autofagia/deficiência , Proteína Homóloga à Proteína-1 Relacionada à Autofagia/genética , Biomarcadores Tumorais/metabolismo , Morte Celular , Proteínas de Ligação a DNA/metabolismo , Feminino , Frutose-Bifosfatase/metabolismo , Genótipo , Células HCT116 , Hexoquinase/metabolismo , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Células MCF-7 , Masculino , Camundongos Knockout , Fenótipo , Fosfofrutoquinase-1/metabolismo , Fosfopiruvato Hidratase/metabolismo , Fosforilação , Proteínas Serina-Treonina Quinases/deficiência , Proteínas Serina-Treonina Quinases/genética , Interferência de RNA , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , Fatores de Tempo , Transfecção , Proteínas Supressoras de Tumor/metabolismo
10.
Cancer Lett ; 376(1): 22-33, 2016 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-27012186

RESUMO

The epithelial-mesenchymal transition (EMT) plays an essential role in embryonic development, wound healing, tissue regeneration, organ fibrosis, and tumor progression. However, the mechanisms underlying this process are poorly understood. Many signaling pathways, including the NF-κB signaling pathway, trigger EMT during development and differentiation. In the present study, we report that N-Myc interactor (NMI) inhibits EMT progression by suppressing transcriptional activities of NF-κB in human gastric cancer cells. We show that the expression of NMI is significantly reduced in invasive gastric cancer cells and gastric cancer tissues. Overexpression of NMI inhibited cell migration and invasion, and this inhibition was enhanced after TNF-α stimulation. Tumorigenicity assay in nude mice support the notion that NMI inhibits EMT in cancer cells. Mechanistically, NMI promotes the interaction between NF-κB/p65 and histone deacetylases (HDACs) and inhibits the acetylation and transcriptional activity of p65. The expression of p65 rescues NMI-mediated inhibition of EMT and the inhibition of the acetylation of p65 mediated by NMI is HDACs-dependent. Taken together, these findings suggest that NMI can suppress tumor invasion and metastasis by inhibiting NF-κB pathways, providing an alternative mechanism for EMT inhibition in stomach neoplasm.


Assuntos
Transição Epitelial-Mesenquimal , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Neoplasias Gástricas/metabolismo , Fator de Transcrição RelA/metabolismo , Acetilação , Animais , Linhagem Celular Tumoral , Movimento Celular , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica , Células HEK293 , Xenoenxertos , Inibidores de Histona Desacetilases/farmacologia , Histona Desacetilases/metabolismo , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/secundário , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/secundário , Masculino , Camundongos Nus , Invasividade Neoplásica , Transplante de Neoplasias , Interferência de RNA , Transdução de Sinais , Neoplasias Gástricas/tratamento farmacológico , Neoplasias Gástricas/genética , Neoplasias Gástricas/patologia , Fatores de Tempo , Fator de Transcrição RelA/genética , Transcrição Gênica , Transfecção , Fator de Necrose Tumoral alfa/farmacologia
11.
Biochim Biophys Acta ; 1839(2): 97-106, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24389345

RESUMO

Sfmbt2-hosted miR-466a-3p and its close relatives are often among the most significantly up-regulated or down-regulated miRNAs in responses to numerous deleterious environmental stimuli. The exact roles of these miRNAs in cellular stress responses, however, are not clear. Here we showed that many Sfmbt2-hosted miRNAs were highly hypertonic stress responsive in vitro and in vivo. In renal medulla, water deprivation induced alterations in the expression of miR-466(a/b/c/e/p)-3p in a pattern similar to that of miR-200b-3p, a known regulator of osmoresponsive transcription factor Nfat5. Remarkably, exposure of mIMCD3 cells to an arginine vasopressin analog time-dependently down-regulated the expression of miR-466(a/b/c/e/p)-3p and miR-200b-3p, which provides a novel regulatory mechanism for these osmoresponsive miRNAs. In cultured mIMCD3 cells we further demonstrated that miR-466a-3p and miR-466g were capable of targeting Nfat5 by interacting with its 3'UTR. In transgenic mice overexpressing miR-466a-3p, significant down-regulation of Nfat5 and many other osmoregulation-related genes was observed in both the renal cortex and medulla. Moreover, sustained transgenic over-expression of miR-466a-3p was found to be associated with polydipsia, polyuria and disturbed ion homeostasis and kidney morphology. Since the mature sequence of miR-466a-3p is completely equivalent to that of miR-466e-3p and that the seed sequence of miR-466a-3p is completely equivalent to that of miR-297(a/b/c)-3p, miR-466d-3p, miR-467g and miR-669d-3p, and that miR-466a-3p differs from miR-466(b/c/p)-3p only in a 5' nucleotide, we propose that miR-466a-3p and many of its close relatives are important epigenetic regulators of renal Nfat5 signaling, osmoregulation and urine concentration in mice.


Assuntos
Íntrons/genética , Capacidade de Concentração Renal/genética , MicroRNAs/genética , Fatores de Transcrição NFATC/genética , Osmorregulação/genética , Fatores de Transcrição/genética , Regiões 3' não Traduzidas/genética , Animais , Arginina Vasopressina/análogos & derivados , Arginina Vasopressina/farmacologia , Sequência de Bases , Western Blotting , Linhagem Celular , Creatina/sangue , Creatina/urina , Epigênese Genética , Expressão Gênica/efeitos dos fármacos , Córtex Renal/metabolismo , Medula Renal/metabolismo , Camundongos , Camundongos Transgênicos , Fatores de Transcrição NFATC/metabolismo , Potássio/sangue , Potássio/urina , Proteínas Repressoras , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Homologia de Sequência do Ácido Nucleico , Transdução de Sinais/genética , Sódio/sangue , Sódio/urina , Ureia/sangue , Ureia/urina
12.
Mol Med Rep ; 9(2): 387-94, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24284654

RESUMO

ArfGAP with SH3 domain, ankyrin repeat and PH domain 3 (ASAP3), previously known as ACAP4, DDEFL1 and UPLC1, is considered to be an important regulator in cancer cell migration/invasion and actin-based cytoskeletal remodeling. However, the underlying mechanisms through which ASAP3 mediates these processes are not well-elucidated. This study reported that in certain types of cancer cells, loss of ASAP3 suppressed cell migration/invasion, in part by destabilizing γ-actin-1 (ACTG1), a cytoskeletal protein considered to be an integral component of the cell migratory machinery, essential for the rearrangement of the dynamic cytoskeletal networks and important in diseases, such as brain malformation, hearing loss and cancer development. The data, for the first time, link ASAP3 with ACTG1 in the regulation of cytoskeletal maintenance and cell motility.


Assuntos
Actinas/genética , Movimento Celular/genética , Proteínas Ativadoras de GTPase/genética , Neoplasias/genética , Proteínas do Citoesqueleto/metabolismo , Proteínas Ativadoras de GTPase/metabolismo , Células Hep G2 , Humanos , Neoplasias/patologia
13.
Free Radic Biol Med ; 67: 91-102, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24161443

RESUMO

Aberrant regulation in oxidative stress, fibrogenesis, and the epithelial-mesenchymal transition (EMT) in renal cells under hyperglycemic conditions contributes significantly to the onset and progression of diabetic nephropathy. The mechanisms underlying these hyperglycemia-induced dysregulations, however, have not been clearly elucidated. Herein, we report that aldose reductase is capable of regulating the expression of miR-200a-3p/141-3p negatively in renal mesangial cells. MiR-200a-3p/141-3p, in turn, act to target Keap1, Tgfß2, fibronectin, and Zeb2 directly and regulate Tgfß1 and Nrf2 indirectly under high-glucose conditions, resulting in profound dysregulations in Keap1-Nrf2, Tgfß1/2, and Zeb1/2 signaling. In vivo in streptozotocin-induced diabetic mice, we found that aldose reductase deficiency caused significant elevations in miR-200a-3p/141-3p in the renal cortex, which were accompanied by a significant downregulation of Keap1, Tgfß1/2, and fibronectin but significant upregulation of Nrf2. Moreover, in vivo administration of inhibitors of miR-200a-3p in diabetic animals significantly exacerbated cortical and glomerular fibrogenesis and increased urinary albumin excretion, tightly linking dysregulated miR-200a-3p with the development of diabetic nephropathy. Collectively, our results reveal a novel mechanism whereby hyperglycemia induces aldose reductase to regulate renal expression of miR-200a-3p/141-3p to coordinately control hyperglycemia-induced renal oxidative stress, fibrogenesis, and the EMT. Our novel findings also suggest that inhibition of aldose reductase and in vivo renal cortical restoration of miR-200a-3p/141-3p or their combination are very promising avenues for the development of therapeutic strategies or drugs against diabetic nephropathy.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Aldeído Redutase/genética , Proteínas do Citoesqueleto/genética , Córtex Renal/metabolismo , Células Mesangiais/metabolismo , MicroRNAs/genética , Transdução de Sinais/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Aldeído Redutase/metabolismo , Animais , Linhagem Celular , Proteínas do Citoesqueleto/metabolismo , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patologia , Nefropatias Diabéticas/genética , Nefropatias Diabéticas/metabolismo , Nefropatias Diabéticas/patologia , Regulação da Expressão Gênica , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Proteína 1 Associada a ECH Semelhante a Kelch , Córtex Renal/patologia , Fatores de Transcrição Kruppel-Like/genética , Fatores de Transcrição Kruppel-Like/metabolismo , Masculino , Células Mesangiais/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , MicroRNAs/metabolismo , Fator 2 Relacionado a NF-E2/genética , Fator 2 Relacionado a NF-E2/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Fator de Crescimento Transformador beta1/genética , Fator de Crescimento Transformador beta1/metabolismo , Fator de Crescimento Transformador beta2/genética , Fator de Crescimento Transformador beta2/metabolismo , Homeobox 2 de Ligação a E-box com Dedos de Zinco , Homeobox 1 de Ligação a E-box em Dedo de Zinco
14.
PLoS One ; 8(9): e73591, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24066058

RESUMO

Hepatic aldose reductase (AR) expression is known to be induced in liver diseases, including hepatitis and hepatocellular carcinoma. However, the role of AR in the development of these diseases remains unclear. We performed this current study to determine whether and how AR might be involved in the development of diet-induced nonalcoholic steatohepatitis. Our results showed that the level of AR protein expression was significantly higher in db/db mice fed the methionine-choline-deficient (MCD) diet than in mice fed the control diet. In parallel with the elevation in AR, steatohepatitis was observed in MCD diet-fed mice, and this diet-induced steatohepatitis was significantly attenuated by lentiviral-mediated knock-down of the AR gene. This suppressive effect of AR knock-down was associated with repressed levels of serum alanine aminotransferase and hepatic lipoperoxides, reduced mRNA and protein expression of hepatic cytochrome P450 2E1 (CYP2E1), and decreased mRNA expression of pro-inflammatory tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Moreover, AR-induced elevations on the level of CYP2E1 expression, reactive oxygen species, mRNA expression of TNF-α and IL-6 were confirmed in AML12 hepatocytes. Further, lentiviral-mediated knock-down of AR ameliorated MCD diet-induced collagen deposition in the livers of db/db mice. With the improvement in liver fibrosis, the mRNA levels of tissue inhibitor of metalloproteinase-1 (TIMP-1) and matrix metalloproteinase-2 (MMP-2), two genes involved in hepatic fibrogenesis, were found to be significantly suppressed, while TIMP-2 and MMP-13 were unaffected. Together these data indicate that inhibition of AR alleviates the MCD diet-induced liver inflammation and fibrosis in db/db mice, probably through dampening CYP2E1 mediated-oxidative stress and ameliorating the expression of pro-inflammatory cytokines.


Assuntos
Aldeído Redutase/metabolismo , Dieta/efeitos adversos , Fígado Gorduroso/enzimologia , Aldeído Redutase/genética , Animais , Western Blotting , Colina , Fígado Gorduroso/etiologia , Fígado Gorduroso/genética , Feminino , Interleucina-6/genética , Metaloproteinase 13 da Matriz/genética , Metaloproteinase 2 da Matriz/genética , Metionina/deficiência , Camundongos , Hepatopatia Gordurosa não Alcoólica , Espécies Reativas de Oxigênio/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Inibidor Tecidual de Metaloproteinase-1/genética , Fator de Necrose Tumoral alfa/genética
15.
Nanotechnology ; 24(16): 165102, 2013 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-23535229

RESUMO

A variety of inorganic nanomaterials have been shown to induce autophagy, a cellular degradation process critical for the maintenance of cellular homeostasis. The overwhelming majority of autophagic responses elicited by nanomaterials were detrimental to cell fate and contributed to increased cell death. A widely held view is that the inorganic nanoparticles, when encapsulated and trapped by autophagosomes, may compromise the normal autophagic process due to the inability of the cells to degrade these materials and thus they manifest a detrimental effect on the well-being of a cell. Here we show that, contrary to this notion, nano-sized paramontroseite VO2 nanocrystals (P-VO2) induced cyto-protective, rather than death-promoting, autophagy in cultured HeLa cells. P-VO2 also caused up-regulation of heme oxygenase-1 (HO-1), a cellular protein with a demonstrated role in protecting cells against death under stress situations. The autophagy inhibitor 3-methyladenine significantly inhibited HO-1 up-regulation and increased the rate of cell death in cells treated with P-VO2, while the HO-1 inhibitor protoporphyrin IX zinc (II) (ZnPP) enhanced the occurrence of cell death in the P-VO2-treated cells while having no effect on the autophagic response induced by P-VO2. On the other hand, Y2O3 nanocrystals, a control nanomaterial, induced death-promoting autophagy without affecting the level of expression of HO-1, and the pro-death effect of the autophagy induced by Y2O3. Our results represent the first report on a novel nanomaterial-induced cyto-protective autophagy, probably through up-regulation of HO-1, and may point to new possibilities for exploiting nanomaterial-induced autophagy for therapeutic applications.


Assuntos
Autofagia/efeitos dos fármacos , Citoproteção/efeitos dos fármacos , Nanopartículas/química , Óxidos/química , Óxidos/farmacologia , Compostos de Vanádio/química , Compostos de Vanádio/farmacologia , Células HeLa , Heme Oxigenase-1/antagonistas & inibidores , Heme Oxigenase-1/genética , Humanos , Regulação para Cima/efeitos dos fármacos
16.
Appl Biochem Biotechnol ; 169(8): 2273-80, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23440637

RESUMO

Quaking (QKI) proteins are important regulators of RNA metabolism and cellular signal transduction. Recent studies have shown that isoforms of QKI proteins, which include QKI5/6/7/7b in human cells, play important roles in the development of neurological diseases and human cancers. In comparison with QKI5/6/7, however, there are little data on QKI7b due to lack of specific antibodies. Here, we reported the preparation and initial characterizations of polyclonal antibodies against human QKI7b. Utilizing a chemically synthesized C-terminal peptide fragment of human QKI7b, we raised two preparations of rabbit antiserum. We found that these antibodies were able to recognize human QKI7b, but not QKI5/6/7. Our immunofluorescence staining showed that in LO2 hepatocytes, QKI7b localizes predominantly in the perinuclear cytoplasm and less abundantly in the nucleus. In clinical samples, we showed that like QKI5/6/7 proteins, QKI7b protein was also significantly downregulated in most human colorectal cancer tissues. These antibodies, therefore, might be useful in future functional studies of QKI7b.


Assuntos
Anticorpos/metabolismo , Proteínas de Ligação a RNA/metabolismo , Animais , Anticorpos/imunologia , Western Blotting , Linhagem Celular , Neoplasias Colorretais/metabolismo , Ensaio de Imunoadsorção Enzimática , Imunofluorescência , Hemocianinas/química , Humanos , Técnicas In Vitro , Proteínas de Ligação a RNA/imunologia , Coelhos , Reação em Cadeia da Polimerase Via Transcriptase Reversa
17.
Gut ; 62(5): 716-26, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-22490519

RESUMO

OBJECTIVE: Deficiency or reduced expression of signal transduction and activation of RNA family protein Quaking (Qki) is associated with developmental defects in neural and vascular tissues and the development of debilitating human diseases including colorectal cancer (CRC). However, the mechanisms underlying the aberrant downregulation or deficiency of Qki were uncertain. DESIGN: Expression of miR-574-5p, Qki5/6/7/7b splicing variants, ß-catenin and p27(Kip1) was determined in mouse and human CRC cells and tissues to investigate the post-transcriptional regulation of Qki isoforms by miR-574-5p and its impact on ß-catenin/p27(Kip1) signalling, cell cycle progression, proliferation, migration, invasion and tumour growth. RESULTS: In the CRC tissues of C57BL/6-Apc(min/+) mice, miR-574-5p was found to be significantly upregulated and negatively correlated with the expression of Qki but positively correlated with the expression of ß-catenin. In mouse and human CRC cells, miR-574-5p was shown to regulate Qki isoforms (Qki6/7 in particular) post-transcriptionally and caused altered expression in ß-catenin and p27(Kip1) , increased proliferation, migration and invasion and decreased differentiation and cell cycle exit. Furthermore, in clinical CRC tissues, miR-574-5p was shown to be greatly upregulated and inversely correlated with the expression of Qkis. Finally, inhibition of miR-574-5p was shown to suppress the growth of tumours in the nude mice. CONCLUSIONS: Together, these novel findings suggest that miR-574-5p is a potent ribo-regulator for Qkis and that aberrant miR-574-5p upregulation can be oncogenic.


Assuntos
Biomarcadores Tumorais/metabolismo , Neoplasias Colorretais/metabolismo , MicroRNAs/metabolismo , Proteínas de Ligação a RNA/metabolismo , Transdução de Sinais , Proteínas Wnt/metabolismo , beta Catenina/metabolismo , Animais , Biomarcadores Tumorais/genética , Neoplasias Colorretais/patologia , Inibidor de Quinase Dependente de Ciclina p27/metabolismo , Regulação para Baixo , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Nus , MicroRNAs/genética , Neoplasias Experimentais , Inibidores de Proteínas Quinases/metabolismo , Proteínas de Ligação a RNA/genética , Reação em Cadeia da Polimerase em Tempo Real , Transplante Heterólogo , Proteínas Wnt/genética , beta Catenina/genética
18.
Nat Chem Biol ; 8(11): 897-904, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22983157

RESUMO

Liver kinase B1 (LKB1) has important roles in governing energy homeostasis by regulating the activity of the energy sensor kinase AMP-activated protein kinase (AMPK). The regulation of LKB1 function, however, is still poorly understood. Here we demonstrate that the orphan nuclear receptor Nur77 binds and sequesters LKB1 in the nucleus, thereby attenuating AMPK activation. This Nur77 function is antagonized by the chemical compound ethyl 2-[2,3,4-trimethoxy-6-(1-octanoyl)phenyl]acetate (TMPA), which interacts with Nur77 with high affinity and at specific sites. TMPA binding of Nur77 results in the release and shuttling of LKB1 to the cytoplasm to phosphorylate AMPKα. Moreover, TMPA effectively reduces blood glucose and alleviates insulin resistance in type II db/db and high-fat diet- and streptozotocin-induced diabetic mice but not in diabetic littermates with the Nur77 gene knocked out. This study attains a mechanistic understanding of the regulation of LKB1-AMPK axis and implicates Nur77 as a new and amenable target for the design and development of therapeutics to treat metabolic diseases.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/metabolismo , Fenilacetatos/farmacologia , Proteínas Serina-Treonina Quinases/metabolismo , Quinases Proteína-Quinases Ativadas por AMP , Proteínas Quinases Ativadas por AMP/antagonistas & inibidores , Animais , Glicemia/efeitos dos fármacos , Células Cultivadas , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Experimental/metabolismo , Ativação Enzimática/efeitos dos fármacos , Células HEK293 , Humanos , Resistência à Insulina , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Obesos , Modelos Moleculares , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/antagonistas & inibidores , Membro 1 do Grupo A da Subfamília 4 de Receptores Nucleares/genética , Fenilacetatos/química , Fosforilação/efeitos dos fármacos , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Transporte Proteico/efeitos dos fármacos , Estreptozocina , Relação Estrutura-Atividade
19.
Leuk Lymphoma ; 53(10): 2033-40, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22448917

RESUMO

Mllt3/Af9 is a proto-oncogene capable of deregulating the expression of genes critical for leukemia. However, the regulation of its expression remains incompletely elucidated. Herein, we show that the microRNAs miR-297b-5p/3p are capable of regulating Mllt3/Af9 expression negatively by binding to its 3'-untranslated region. Overexpression of miR-297b-5p/3p also led to altered expression of p27(Kip1) and proliferating cell nuclear antigen, abnormal cell cycle arrest, decreased cell proliferation, migration and invasion in vitro in cell cultures, and suppressed xenograft tumor growth in vivo in the nude mouse. These data demonstrate that miR-297b-5p/3p and Mllt3/Af9 might be critical regulators of lymphoma cell proliferation or carcinogenesis. Together our findings suggest that miR-297b-5p/3p might be useful molecular targets for diagnosis or treatment of cancers associated with abnormal expression of Mllt3/Af9.


Assuntos
Movimento Celular/genética , Linfoma/genética , MicroRNAs/genética , Proteínas Nucleares/genética , Regiões 3' não Traduzidas , Animais , Sequência de Bases , Ciclo Celular/genética , Linhagem Celular Tumoral , Proliferação de Células , Inibidor de Quinase Dependente de Ciclina p27/genética , Inibidor de Quinase Dependente de Ciclina p27/metabolismo , Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Linfoma/metabolismo , Linfoma/patologia , Camundongos , Camundongos Nus , MicroRNAs/química , MicroRNAs/metabolismo , Dados de Sequência Molecular , Proteínas Nucleares/química , Processamento Pós-Transcricional do RNA
20.
Exp Diabetes Res ; 2012: 789730, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22110479

RESUMO

We previously demonstrated in streptozotocin-induced diabetic mice that deficiency or inhibition of aldose reductase (AR) caused significant dephosphorylation of hepatic transcriptional factor PPARα, leading to its activation and significant reductions in serum lipid levels. Herein, we report that inhibition of AR by zopolrestat or by a short-hairpin RNA (shRNA) against AR caused a significant reduction in serum and hepatic triglycerides levels in 10-week old diabetic db/db mice. Meanwhile, hyperglycemia-induced phosphorylation of hepatic ERK1/2 and PPARα was significantly attenuated in db/db mice treated with zopolrestat or AR shRNA. Further, in comparison with the untreated db/db mice, the hepatic mRNA expression of Aco and ApoA5, two target genes for PPARα, was increased by 93% (P < 0.05) and 73% (P < 0.05) in zopolrestat-treated mice, respectively. Together, these data indicate that inhibition of AR might lead to significant amelioration in hyperglycemia-induced dyslipidemia and nonalcoholic fatty liver disease.


Assuntos
Aldeído Redutase/antagonistas & inibidores , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus/tratamento farmacológico , Inibidores Enzimáticos/administração & dosagem , Fígado Gorduroso/prevenção & controle , PPAR alfa/fisiologia , Aldeído Redutase/deficiência , Animais , Benzotiazóis/administração & dosagem , Diabetes Mellitus Tipo 2/complicações , Hiperglicemia/metabolismo , Fígado/química , Masculino , Camundongos , Camundongos Knockout , Hepatopatia Gordurosa não Alcoólica , Fosforilação , Ftalazinas/administração & dosagem , RNA Interferente Pequeno/administração & dosagem , Triglicerídeos/análise , Triglicerídeos/sangue
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