Effect of aging and obesity on GLUT12 expression in small intestine, adipose tissue, muscle, and kidney and its regulation by docosahexaenoic acid and exercise in mice

Obesity is characterized by excessive fat accumulation and inflammation. Aging has also been characterized as an inflammatory condition, frequently accompanied by accumulation of visceral fat. Beneficial effects of exercise and n-3 long-chain polyunsaturated fatty acids in metabolic disorders have been described. Glucose transporter 12 (GLUT12) is one of the less investigated members of the GLUT family. Glucose, insulin, and tumor necrosis factor alpha (TNF-α) induce GLUT12 translocation to the membrane in muscle, adipose tissue, and intestine. We aimed to investigate GLUT12 expression in obesity and aging, and under diet supplementation with docosahexaenoic acid (DHA) alone or in combination with physical exercise in mice. Aging increased GLUT12 expression in intestine, kidney, and adipose tissue, whereas obesity reduced it. No changes on the transporter occurred in skeletal muscle. In obese 18-month-old mice, DHA further decreased GLUT12 in the 4 organs. Aerobic exercise alone did not modify GLUT12, but the changes triggered by exercise were able to prevent the DHA-diminishing effect, and almost restored GLUT12 basal levels. In conclusion, the downregulation of metabolism in aging would be a stimulus to upregulate GLUT12 expression. Contrary, obesity, an excessive energy condition, would induce GLUT12 downregulation. The combination of exercise and DHA would contribute to restore basal function of GLUT12. Novelty In small intestine, kidney and adipose tissue aging increases GLUT12 protein expression whereas obesity reduces it. Dietary DHA decreases GLUT12 in small intestine, kidney, adipose tissue and skeletal muscle. Exercise alone does not modify GLUT12 expression, nevertheless exercise prevents the DHA-diminishing effect on GLUT12.

Drug discovery and chemical probing in Drosophila

Flies are increasingly utilized in drug discovery and chemical probing in vivo, which are novel technologies complementary to genetic probing in fundamental biological studies. Excellent genetic conservation, small size, short generation time, and over one hundred years of genetics make Drosophila an attractive model for rapid assay readout and use of analytical amounts of compound, enabling the experimental iterations needed in early drug development at a fraction of time and costs. Here, we describe an effective drug-testing pipeline using adult flies that can be easily implemented to study several disease models and different genotypes to discover novel molecular insight, probes, quality lead compounds, and develop novel prototype drugs.

Protective effect of essential oil of Cinnamomum verum bark on hepatic and renal toxicity induced by carbon tetrachloride in rats

The inner bark of cinnamon (Cinnamomum verum) is widely used as a spice. Cinnamon plants are also a valuable source of essential oil used for medicinal purposes. The present study aimed to investigate the composition and in vitro antioxidant activity of essential oil of C. verum bark (CvEO) and its protective effects in vivo on CCl₄-induced hepatic and renal toxicity in rats. Groups of animals were pretreated for 7 days with CvEO (70 or 100 mg/kg body weight) or received no treatment and on day 7 a single dose of CCl₄ was used to induce oxidative stress. Twenty-four hours after CCl₄ administration, the animals were euthanized. In the untreated group, CCl₄ induced an increase in serum biochemical parameters and triggered oxidative stress in both liver and kidneys. CvEO (100 mg/kg) caused significant reductions in CCl₄-elevated levels of alanine transaminase, aspartate transaminase, alkaline phosphatase, γ-glutamyl transferase, lactate dehydrogenase, total cholesterol, triglycerides, low-density lipoprotein, urea, and creatinine and increased the level of high-density lipoprotein compared with the untreated group. Moreover, pretreatment with CvEO at doses of 70 and 100 mg/kg before administration of CCl₄ produced significant reductions in thiobarbituric acid reactive substances and protein carbonyl levels in liver and kidney tissues compared with the untreated group. The formation of pathological hepatic and kidney lesions induced by the administration of CCl₄ was strongly prevented by CvEO at a dose of 100 mg/kg. Overall, this study suggests that administration of CvEO has high potential to quench free radicals and alleviate CCl₄-induced hepatorenal toxicity in rats.

Traumatic brain injury: classification, models, and markers

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality worldwide. Due to its high incidence rate and often long-term sequelae, TBI contributes significantly to increasing costs of health care expenditures annually. Unfortunately, advances in the field have been stifled by patient and injury heterogeneity that pose a major challenge in TBI prevention, diagnosis, and treatment. In this review, we briefly discuss the causes of TBI, followed by its prevalence, classification, and pathophysiology. The current imaging detection methods and animal models used to study brain injury are examined. We discuss the potential use of molecular markers in detecting and monitoring the progression of TBI, with particular emphasis on microRNAs as a novel class of molecular modulators of injury and its repair in the neural tissue.

The role of suppression of hepatic SCD1 expression in the metabolic effects of dietary methionine restriction

Dietary methionine restriction (MR) produces concurrent increases in energy intake and expenditure, but the proportionately larger increase in energy expenditure (EE) effectively limits weight gain and adipose tissue accretion over time. Increased hepatic fibroblast growth factor-21 (FGF21) is essential to MR-dependent increases in EE, but it is unknown whether the downregulation of hepatic stearoyl-coenzyme A desaturase-1 (SCD1) by MR could also be a contributing factor. Global deletion of SCD1 mimics cold exposure in mice housed at 23 °C by compromising the insular properties of the skin. The resulting cold stress increases EE, limits fat deposition, reduces hepatic lipids, and increases insulin sensitivity by activating thermoregulatory thermogenesis. To examine the efficacy of MR in the absence of SCD1 and without cold stress, the biological efficacy of MR in Scd1^-/- mice housed near thermoneutrality (28 °C) was evaluated. Compared with wild-type mice on the control diet, Scd1^-/- mice were leaner, had higher EE, lower hepatic and serum triglycerides, and lower serum leptin and insulin. Although dietary MR increased adipose tissue UCP1 expression, hepatic Fgf21 messenger RNA, 24 h EE, and reduced serum triglycerides in Scd1^-/- mice, it failed to reduce adiposity or produce any further reduction in hepatic triglycerides, serum insulin, or serum leptin. These findings indicate that even when thermal stress is minimized, global deletion of SCD1 mimics and effectively masks many of the metabolic responses to dietary MR. However, the retention of several key effects of dietary MR in this model indicates that SCD1 is not a mediator of the biological effects of the diet.

Molecular determinants of rotavirus virulence: localization of a potential virulence site in a murine rotavirus VP4

The molecular basis of pathogenesis in vivo for a virulent mouse rotavirus (MRV) and a less virulent bovine rotavirus (BRV) were compared under in vitro and in vivo conditions. Obvious differences in the mobility of several genomic RNA segments were observed in one-dimensional gels. Under in vitro conditions, partial proteolytic peptide mapping identified differences between the two outer capsid proteins of these virus and no difference in inner capsid protein was observed. Since it has been observed by us and others that the gene coding for VP4 protein plays a significant role in determining virulence, the variability observed in the present study between the 84 k proteins (VP4) provided a basis for further investigations in order to locate a potential virulence determinant. A comparison of the carboxypeptidase digests of the MRV- and BRV-VP4 revealed an area of variability between amino acids 307 and 407, which may represent a site of virulence determinant. Under in vivo conditions the virulence of both parenteral BRV and MRV isolates and their corresponding reassortants (with replaced gene 4) were studied in murine and bovine hosts. Like their parents, BRV and MRV isolates, reassortants obtained by replacement of gene 4 in BRV with MRV gene 4 indicated that the dose of the virus isolate used and the clinical outcome in vivo was determined by gene segment 4. The implications of these findings to elucidate the molecular basis of pathogenesis of rotaviruses are discussed.