Hepatic protein tyrosine phosphatase Shp2 disruption mitigates the adverse effects of ethanol in the liver by modulating oxidative stress and ERK signaling.

AIMS: Chronic excessive alcohol intake is a significant cause of alcohol-associated liver disease (ALD), a leading contributor to liver-related morbidity and mortality. The Src homology phosphatase 2 (Shp2; encoded by Ptpn11) is a widely expressed protein tyrosine phosphatase that modulates hepatic functions, but its role in ALD is mostly uncharted. MAIN METHODS: Herein, we explore the effects of liver-specific Shp2 genetic disruption using the established chronic-plus-binge mouse model of ALD. KEY FINDINGS: We report that the hepatic Shp2 disruption had beneficial effects and partially ameliorated ethanol-induced injury, inflammation, and steatosis in the liver. Consistently, Shp2 deficiency was associated with decreased ethanol-evoked activation of extracellular signal-regulated kinase (ERK) and oxidative stress in the liver. Moreover, primary hepatocytes with Shp2 deficiency exhibited similar outcomes to those observed upon Shp2 disruption in vivo, including diminished ethanol-induced ERK activation, inflammation, and oxidative stress. Furthermore, pharmacological inhibition of ERK in primary hepatocytes mimicked the effects of Shp2 deficiency and attenuated oxidative stress caused by ethanol. SIGNIFICANCE: Collectively, these findings highlight Shp2 as a modulator of hepatic oxidative stress upon ethanol challenge and suggest the evaluation of this phosphatase as a potential therapeutic target for ALD.

Mechanisms of inactivation of the tumour suppressor gene RHOA in colorectal cancer.

BACKGROUND: Reduced RHOA signalling has been shown to increase the growth/metastatic potential of colorectal tumours. However, the mechanisms of inactivation of RHOA signalling in colon cancer have not been characterised. METHODS: A panel of colorectal cancer cell lines and large cohorts of primary tumours were used to investigate the expression and activity of RHOA, as well as the presence of RHOA mutations/deletions and promoter methylation affecting RHOA. Changes in RHOA expression were assessed by western blotting and qPCR after modulation of microRNAs, SMAD4 and c-MYC. RESULTS: We show here that RHOA point mutations and promoter hypermethylation do not significantly contribute to the large variability of RHOA expression observed among colorectal tumours. However, RHOA copy number loss was observed in 16% of colorectal tumours and this was associated with reduced RHOA expression. Moreover, we show that miR-200a/b/429 downregulates RHOA in colorectal cancer cells. In addition, we found that TGF-ß/SMAD4 upregulates the RHOA promoter. Conversely, RHOA expression is transcriptionally downregulated by canonical Wnt signalling through the Wnt target gene c-MYC that interferes with the binding of SP1 to the RHOA promoter in colon cancer cells. CONCLUSIONS: We demonstrate a complex pattern of inactivation of the tumour suppressor gene RHOA in colon cancer cells through genetic, transcriptional and post-transcriptional mechanisms.

Loss of the EPH receptor B6 contributes to colorectal cancer metastasis.

Although deregulation of EPHB signaling has been shown to be an important step in colorectal tumorigenesis, the role of EPHB6 in this process has not been investigated. We found here that manipulation of EPHB6 levels in colon cancer cell lines has no effect on their motility and growth on a solid substrate, soft agar or in a xenograft mouse model. We then used an EphB6 knockout mouse model to show that EphB6 inactivation does not efficiently initiate tumorigenesis in the intestinal tract. In addition, when intestinal tumors are initiated genetically or pharmacologically in EphB6+/+ and EphB6-/- mice, no differences were observed in animal survival, tumor multiplicity, size or histology, and proliferation of intestinal epithelial cells or tumor cells. However, reintroduction of EPHB6 into colon cancer cells significantly reduced the number of lung metastasis after tail-vein injection in immunodeficient mice, while EPHB6 knockdown in EPHB6-expressing cells increased their metastatic spread. Consistently, although EPHB6 protein expression in a series of 130 primary colorectal tumors was not associated with patient survival, EPHB6 expression was significantly lower in lymph node metastases compared to primary tumors. Our results indicate that the loss of EPHB6 contributes to the metastatic process of colorectal cancer.

Investigation of the role of tyrosine kinase receptor EPHA3 in colorectal cancer.

EPH signaling deregulation has been shown to be important for colorectal carcinogenesis and genome-wide sequencing efforts have identified EPHA3 as one of the most frequently mutated genes in these tumors. However, the role of EPHA3 in colorectal cancer has not been thoroughly investigated. We show here that ectopic expression of wild type EPHA3 in colon cancer cells did not affect their growth, motility/invasion or metastatic potential in vivo. Moreover, overexpression of mutant EPHA3 or deletion of the endogenous mutant EPHA3 in colon cancer cells did not affect their growth or motility. EPHA3 inactivation in mice did not initiate the tumorigenic process in their intestine, and had no effects on tumor size/multiplicity after tumor initiation either genetically or pharmacologically. In addition, immunohistochemical analysis of EPHA3 tumor levels did not reveal associations with survival or clinicopathological features of colorectal cancer patients. In conclusion, we show that EPHA3 does not play a major role in colorectal tumorigenesis. These results significantly contribute to our understanding of the role of EPH signaling during colorectal carcinogenesis, and highlighting the need for detailed functional studies to confirm the relevance of putative cancer driver genes identified in sequencing efforts of the cancer genome.

Aerobic Training Increases Expression Levels of SIRT3 and PGC-1α in Skeletal Muscle of Overweight Adolescents Without Change in Caloric Intake.

Sirtuin 3 enzyme (SIRT3) is involved in the regulation of mitochondrial energy homeostasis by activating Peroxisome proliferator-activated receptor-gamma coactivator (PGC-1α). Murine models have shown that the protein SIRT3 was modified by exercise and diet, however, the effect of exercise without diet in humans has not been examined. Propose of this paper was to analyze the effect of aerobic training on SIRT3 and PGC-1α in skeletal muscle of overweight adolescents without change in caloric intake. Fourteen overweight or obese male adolescents (15.5 ± 0.8 years) trained 3 days-week/50 min × session, at 70-80% of maximal heart rate for 12 weeks. Anthropometrics and skeletal muscle biopsies from the vastus lateralis were taken before and after the exercise program to measure adiposity, SIRT3, and PGC-1α proteins. Peak aerobic capacity (VO2peak) was estimated before and after training. The participants did not change their eating habits during the intervention. SIRT3 (1.05 ± 0.11 vs. 1.25 ± 0.14 AU, p = .014) and PGC-1a (1.06 ± 0.15 Vs 1.39 ± 0.20 AU, p = .009) increased. Fat percentage and waist circumference decreased (p < .05). VO2peak increased after training (p < .001). There was a significant association between SIRT3 and PGC-1α after training program. These data suggest that aerobic training increased SIRT3 and PGC-1a expression levels in sedentary, overweight, or obese adolescents.

A PPARγ, NF-κB and AMPK-dependent mechanism may be involved in the beneficial effects of curcumin in the diabetic db/db mice liver.

Turmeric (Curcuma longa) is a rhizomatous herbaceous perennial plant of the ginger family which has been used to treat biliary disorders, anorexia, cough, rheumatism, cancer, sinusitis, hepatic disorders, hyperglycemia, obesity, and diabetes in both Ayurvedic and Traditional Chinese Medicine. Suggested mechanisms of action include the modulation of signal transduction cascades and effects on gene expression, however they remain to be elucidated. In this study, the expression of some proteins responsible for transcription factors, inflammation, and metabolic control were evaluated by western blot in 15-week-old db/db mice livers treated with curcumin 0.75% mixed in their diet for 8 weeks. In addition, nitrosative stress was evaluated. Curcumin increased the expression of AMPK and PPARγ, and diminished NF-κB protein in db/db mice. However, it did not modify the expression of PGC-1α or SIRT1. Nitrosative stress present in db/db mice livers was determined by a unique nitrotyrosylated protein band (75 kDa) and was not reverted with curcumin. In conclusion, curcumin regulates the expression of AMPK, PPARγ, and NF-κB; suggesting a beneficial effect for treatment of T2DM complications. In order to observe best beneficial effects it is desirable to administer curcumin in the earlier states of T2DM.

[Contributions of proteomics in the study of diabetes]. / Aportaciones de la proteómica en el estudio de la diabetes.

The incidence of type 2 diabetes mellitus (T2D) is growing rapidly due to aging, urbanization, changes in lifestyle, and increasing prevalence of obesity. In T2D, chronic hyperglycemia leads to macro and micro vascular complications, which currently are serious problem for health systems worldwide. The complexity of T2D and its complications requires study skills of high performance that provide important information in the understanding of the pathophysiology of the disease and biological pathways involved in development of T2D and its complications. In this work we describe the recent contributions of proteomics in the study of T2D and discuss its importance in the identification of therapeutic targets and biomarkers that help to improve the diagnosis of T2D, monitor the disease progression, and the development of new drugs to improve treatment and reduce its complications.

Serum concentrations of p,p'-dichlorodiphenyltrichloroethane (p,p'-DDE) in a sample of agricultural workers from Bolivia.

Organochlorine pesticide p,p'-dichlorodiphenyltrichloroethane (DDT) is still used for vector control in several tropical and subtropical areas of South America and there is evidence of recent illegal use in agriculture. Its main breakdown product in the environment and living organisms is p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE), which is considered a marker of past exposure to DDT. The aim of the present study was to assess human exposure to p,p'-DDE in a sample of agricultural farmers from three rural communities in eastern Bolivia. In addition, o,p'-DDT was analyzed as a surrogate of a potential ongoing exposure to the pesticide. Face-to-face questionnaires were performed, and serum samples were analyzed by high-resolution gas chromatography with mass spectrometry. p,p'-DDE was found in 100% of the samples, with a median concentration of 19.7ngmL(-1) (4788.7ng/g lipid), while o,p'-DDT was detected in 3 samples (4.3%). Serum p,p'-DDE concentrations were associated with time of residence in the study area, personal hygiene after work, and body mass index in adjusted multinomial logistic regression models with tertiles of p,p'-DDE as the dependent variable. The present results revealed high levels of exposure to p,p'-DDE, which might be derived from a heavily polluted local environment and past occupational exposure. These findings deserve further attention due to the potential associated health risks and point to the need for the continuous monitoring of these populations.

Uso del DIU Tcu 380 modificado con filamentos de cromo en el posparto inmediato / Use of modified intrauterine device (IUD) Tcu 380 with filaments Cr at inmediate post-partum

La aplicación del dispositivo intrauterino (DIU) postalumbramiento of rece muchas ventajas de acuerdo al programa de planificación familiar, por lo que su utilización se ha visto en aumento. Sin embargo, su principal desventaja es el alto porcentaje de expulsión que varía desde 4 a 60 por ciento, de estas expulsiones, 20 por ciento transcurre sin que la usuaria lo detecte. Los DIU modificados con filamentos de cromo, se cree que pueden proporcionar una mayor fijación al endometrio, debido al tiempo en que tarda el cromo en absorberse, permitiendo por tanto, menor posibilidad de expulsión. Con esta idea determinamos si el DIU provisto de filamentos de cromo favorece la adhesión al endometrio y con ello la disminución del porcentaje de expulsión de forma inadvertida. En el periodo de un año de estudio, se incluyeron 150 mujeres, de las cuales se concluyó el seguimiento en 84 pacientes, a quienes se aplicó un DIU (TCu 380) modificado con catgut crómico número 0 (ccO) en su rama transversal, dentro de los 10 minutos postalumbramiento. Se realizaron tres revisiones, durante el puerperio inmediato, mediato y tardío, para evaluar la expulsión del DIU. Se comparó la presencia o expulsión según el momento del puerperio, tomando en cuenta la paridad, edad y estado civil. Un total de 14 DIU modificados (16.6 por ciento) fueron expulsados, presentando frecuencias similares de expulsión en el puerperio inmediato y mediato, sin diferencia estadísticamente significativa, con ninguna expulsión en el puerperio tardío. Las pacientes primíparas tuvieron el mayor porcentaje de expulsión (22.8 por ciento), así como las mujeres solteras y en unión libre con 20.5 y 20.6 por ciento, respectivamente. La edad en que se presentó el mayor índice de expulsión fue en mujeres menores de 30 años; solo hubo un caso de expulsión inadvertida. Nuestros resultados muestran que la edad, paridad y estado civil no tienen una influencia directa sobre la expulsión del DIU modificado con filamentos de cromo, ya que en todas se obtuvo una p > 0.05 al considerar cada etapa del puerperio, solo en el puerperio tardío no se presentó expulsión de DIU, lo que es consecuencia de la disminución de la cavidad uterina y cierre del cérvix. El DIU TCu 380 modificado con filamentos de cromo, mostró un porcentaje de expulsión por arriba de los informes previos para otros tipos de DIU modificados, pero inferiores a los porcentajes de expulsión de los DIU sin modificar.