Mohamed Mohamed Ahmed

Butyrate regulates leptin expression through different signaling pathways in adipocytes

Leptin is an adipocytokine that regulates body weight, and maintains energy homeostasis by promoting reduced food intake and increasing energy expenditure. Leptin expression and secretion is regulated by various factors including hormones and fatty acids. Butyrate is a short-chain fatty acid that acts as source of energy in humans. We determined whether this fatty acid can play a role in leptin expression in fully differentiated human adipocytes. Mature differentiated adipocytes were incubated with or without increasing concentrations of butyrate. RNA was extracted and leptin mRNA expression was examined by Northern blot analysis. Moreover, the cells were incubated with regulators that may affect signals which may alter leptin expression and analyzed with Northern blotting. Butyrate stimulated leptin expression, and stimulated mitogen activated protein kinase (MAPK) and phospho-CREB signaling in a time-dependent manner. Prior treatment of the cells with signal transduction inhibitors as pertusis toxin, Gi protein antagonist, PD98059 (a MAPK inhibitor), and wortmannin (a PI3K inhibitor) abolished leptin mRNA expression. These results suggest that butyrate can regulate leptin expression in humans at the transcriptional level. This is accomplished by: 1) Gi protein-coupled receptors specific for short-chain fatty acids, and 2) MAPK and phosphatidylinositol-3-kinase (PI3K) signaling pathways.

l-Carnitine protects against testicular dysfunction caused by gamma irradiation in mice

This study was conducted on mice to evaluate the radioprotective role of L-carnitine against γ-ray irradiation-induced testicular damage. Adult male mice were exposed to whole body irradiation at a total dose of 1 Gy. Radiation exposure was continued 24 h a day (0.1 Gy/day) throughout the 10 days exposure period either in the absence and/or presence of L-carnitine at an i.p. dose of 10 mg/kg body weight/day. Results revealed that γ-rays irradiation suppressed the expression of ABP and CYP450SCC mRNA, whereas treatment with L-carnitine prior and throughout γ-rays irradiation exposure inhibited this suppression. Treatment with γ-ray irradiation or L-carnitine down-regulated expression of aromatase mRNA. With combined treatment, L-carnitine significantly normalized aromatase expression. γ-Ray irradiation up-regulated expression of FasL and Cyclin D2 mRNA, while L-carnitine inhibited these up-regulations. Results also showed that γ-ray-irradiation up-regulated TNF-α, IL1-β and IFN-γ mRNA expressions compared to either controls or the L-carnitine treated group. Moreover, γ-irradiation greatly reduced serum testosterone levels, while L-carnitine, either alone or in combination with irradiation, significantly increased serum testosterone levels compared to controls. In addition, γ-irradiation induced high levels of sperm abnormalities (43%) which were decreased to 12% in the presence of L-carnitine. In parallel with these findings, histological examination showed that γ-irradiation induced severe tubular degenerative changes, which were reduced by L-carnitine pre-treatment. These results clarified the immunostimulatory effects of L-carnitine and its radioprotective role against testicular injury.

Retinol binding protein 4 in dairy cows : its presence in colostrum and alteration in plasma during fasting, inflammation, and the peripartum period

Retinol-binding protein 4 (RBP4) is a plasma protein involved in retinol transportation, and recent evidence in rodents suggests that RBP4 is also a metabolic regulator that modifies insulin sensitivity. To assess how RBP4 levels are regulated in ruminants, we determined the RBP4 concentrations in bovine plasma and milk using Western blot analysis. Plasma RBP4 levels in non-pregnant non-lactating (control) cows were around 45 microg/ml, which were sustained during 60-h fasting, but decreased significantly 4 h after lipopolysaccharide (LPS) administration. Basal plasma retinol concentration was around 30 microg/dl, but this decreased to approximately one-third and one-half of these values during fasting and 8 h after LPS challenge, respectively. Plasma RBP4 and retinol levels in cows 3-6 d before parturition were comparable to those of the controls. However, on the day of parturition both were significantly decreased and had returned to basal levels by two weeks after calving. Interestingly, RBP4 was clearly detected in colostrum (16.4+/-5.6 microg/ml) but was only faintly detected in milk from cows at 7 d and 15 d after calving. Retinol concentrations in colostrum were almost 10-fold higher than those in plasma, while those in milk were comparable to those in plasma. These results suggest that RBP4 and retinol levels are independently regulated under physiological and pathophysiological conditions and that RBP4, like retinol, is transferred from maternal stores to calves through colostrum.

Renoprotective effect of curcumin against the combined oxidative stress of diabetes and nicotine in rats

The progression of diabetic nephropathy (DN) is accelerated by smoking. The current study investigated the ability of curcumin to protect the kidneys against damage from oxidative stress induced by diabetes mellitus (DM) and nicotine (NC). A total of 24 male Wistar rats were divided into four groups of six rats each. DM was induced by a single intraperitoneal injection of streptozotocin 60 mg/kg body weight. DM rats were treated with or without NC in the absence or presence of curcumin for 8 weeks. As compared with the controls, DM rats exhibited reduced serum levels of high density lipoprotein, superoxide dismutase and glutathione peroxidase, and decreased renal mRNA expression levels of synaptopodin, connexin 43 and erythropoietin (EPO), which were further suppressed by NC and restored to normal levels by curcumin treatment. Additionally, DM rats exhibited increases in their lipid profiles (cholesterol, triacylglycerol and phospholipids), oxidative markers (malondialdehyde, γ-glutamyltranspeptidase and nitric oxide), kidney function markers (urea and creatinine) and the mRNA expression levels of vimentin, desmin, SREBP-1, iNOS and TGF-β1. These effects were further enhanced by NC, but counteracted by curcumin treatment. Kidneys from DM rats displayed glomerular hypertrophy, sclerosis and tubulo-interstitial changes represented by tubular lipid deposition, interstitial mononuclear cell infiltration and fibroplasia. Pancreatic islets exhibited cellular vacuolation, morphological irregularity and damaged or reduced in size β-cells. These renal and pancreatic changes became more severe following NC treatment and were ameliorated by curcumin. Therefore, NC-induced DN progression may predominantly operate by increasing oxidative stress, reducing the levels of antioxidants, suppressing EPO levels, and causing perturbations to gap junction and podocyte structure. Curcumin may ameliorate the damaging effects of DM and NC on the kidney through normalization of the mRNA expression levels of several genes important in the progression of DN.

Anti-obesity effects of Taif and Egyptian pomegranates: molecular study

The present study investigated the anti-obesity effects of pomegranate (Punica granatum) juices from the two Saudi Arabian, Taif red, Taif white, and Egyptian pomegranates in high-fat diet (HFD)-induced obese rats. Administrating any of the used juices decreased the body weight gain, food consumption, and serum levels of lipid, leptin, and glucose, while it increased serum insulin level. Histologically, all types of juices decreased the number and size of lipid droplets in hepatocytes compared to the obese, non-treated animals. All juices types upregulated the hepatic mRNA expression of hormone-sensitive lipase, pyruvate kinase, and adiponectin in obese rats; the genes were all suppressed by HFD feeding. Additionally, the expression of fatty acid synthase, sterol regulatory element-binding protein-1c, and acetyl-CoA carboxylase1 was also upregulated by all types of juices. Conversely, ghrelin mRNA expression was downregulated by all used juices’ types. These findings demonstrate that all types of tested juices protect against the HFD-induced obesity in rats. Effect of pomegranate juices on lipid accumulation in liver. H&E and oil red O staining

Impact of aspartame and saccharin on the rat liver: Biochemical, molecular, and histological approach.

The current work was undertaken to settle the debate about the toxicity of artificial sweeteners (AS), particularly aspartame and saccharin. Twenty-five, 7-week-old male Wistar albino rats with an average body weight of 101 ± 4.8 g were divided into a control group and four experimental groups (n = 5 rats). The first and second experimental groups received daily doses equivalent to the acceptable daily intake (ADI) of aspartame (250 mg/Kg BW) and four-fold ADI of aspartame (1000 mg/Kg BW). The third and fourth experimental groups received daily doses equivalent to ADI of saccharin (25 mg/Kg BW) and four-fold ADI of saccharin (100 mg/Kg BW). The experimental groups received the corresponding sweetener dissolved in water by oral route for 8 weeks. The activities of enzymes relevant to liver functions and antioxidants were measured in the blood plasma. Histological studies were used for the evaluation of the changes in the hepatic tissues. The gene expression levels of the key oncogene (h-Ras) and the tumor suppressor gene (P27) were also evaluated. In addition to a significant reduction in the body weight, the AS-treated groups displayed elevated enzymes activities, lowered antioxidants values, and histological changes reflecting the hepatotoxic effect of aspartame and saccharin. Moreover, the overexpression of the key oncogene (h-Ras) and the downregulation of the tumor suppressor gene (P27) in all treated rat groups may indicate a potential risk of liver carcinogenesis, particularly on long-term exposure.

Efficient Newly Designed Primers for the Amplification and Sequencing of Bird Mitochondrial Genomes

In the present study, 27 mitochondrial genomes of diverse avian supra-orders were collected from the Genbank database and their genes were aligned separately. From the alignments, the conserved sequences were selected to design novel conserved primers for amplification and sequencing of the different mitochondrial genes. The reproducibility of these primers was tested in the amplification and sequencing of diverse avian supra-order mitochondrial genomes and was confirmed. This method helped in designing a new set of primers to accelerate both the amplification and the sequencing of bird mitogenomes. It also aids in building mitogenome markers in studying the genetic framework of endemic birds as a preliminary strategy for conservation management of them.

Genetic polymorphism in β-lactoglobulin gene of some sheep breeds in the Kingdom of Saudi Arabia (KSA) and its influence on milk composition

β-Lactoglobulin (β-Lg) is one of the most important proteins in mammals’ milk. It plays a crucial role in milk quality. The polymorphism of β-Lg gene can be used as a marker system . To analyze the genotype distribution of β-Lg gene in some sheep breeds reared in Taif region of Saudi Arabia and its influence on milk composition, sixty (60) animals belonging to four sheep breeds named Noami, Sawakni, Harry and Nagdi, were utilized. The polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) test was performed and genetic polymorphism was detected by the digestion of a 452 bp PCR fragment of exon II of β-Lg gene with the endonuclease Rsa I. The results revealed that Noami and Sawakni breeds belong to β-Lg -A genotype while Harry and Nagdi belong to genotype β-Lg -B. Sequence analysis of a 340 bp fragment in the promoter region of β-Lg showed polymorphism among the examined breeds. Analysis of milk composition in the different breeds indicated that the total protein content of milk was the highest in Noami breed followed by Sawakni, Nagdi and Harry. Concerning milk total fat and total solids contents, Harry breed was the highest, while no significant difference was evident among different breeds in lactose or non-fat solid contents. These results indicate the feasibility of PCR-RFLP test for differentiating sheep breeds and the existence of a significant relationship between β-Lg -A genotype and total milk protein content while no clear association between β-Lg genotypes and other milk content was proved.

Geldanamycin enhances hepatocyte growth factor stimulation of eNOS phosphorylation in endothelial cells

Previously, we demonstrated that hepatocyte growth factor (HGF) potently stimulates endothelial nitric oxide synthase (eNOS) activity and nitric oxide (NO) production through a calcium- and Akt-mediated phosphorylation at Ser-1179 (Ser-1177 human) in bovine aortic endothelial cells. The regulation of eNOS, however, also involves interaction with chaperone proteins such as heat shock protein (HSP) 90, which can be enhanced by agonist stimulation of the enzyme. In the present work, the role of HSP90 in HGF stimulation of eNOS was examined in an endothelial cell culture system. Treatment of endothelial cells with geldanamycin, a commonly used HSP90 inhibitor, augmented HGF-stimulated eNOS phosphorylation at Ser-1179, while it did not alter eNOS phosphorylation at Thr-497. However, other HSP90 inhibitors, namely 17-(allylamino)-17-demethoxygeldanamycin (17-AAG) and radicicol, did not possess similar effects. Neither HGF nor geldanamycin treatment, independently or in combination, altered HSP90/eNOS interaction in endothelial cells. In addition, geldanamycin treatment did not enhance the HGF-induced phosphorylation of Akt, ERK1/2 and p38MAPK. Src kinase inhibition by PP2 also failed to block the geldanamycin effects. These results suggest that geldanamycin, but neither 17-AAG nor radicicol, may enhance HGF-mediated eNOS Ser-1179 phosphorylation by some as yet unknown mechanisms independently of HSP90 inhibition.

Synthesis, characterization, and efficacy evaluation of a new anti-diabetic vanadyl(II) thiamine hydrochloride complex in streptozotocin-induced diabetic rats:

Diabetes mellitus (DM) is a chronic metabolic disorder characterized by hyperglycemia due to abnormalities in either insulin secretion or action. A range of vanadium complexes have been synthesized and demonstrated to be effective in lowering hyperglycemia. Thiamine administration was also reported to prevent deterioration in fasting glucose and insulin levels, and to improve glucose tolerance in hyperglycemic patients. This study has been conducted to evaluate the ionic vanadyl(II) thiamine hydrochloride complex (VC) as a new anti-diabetic candidate. The new complex was characterized by infrared spectroscopy (FT-IR), electronic spectra, magnetic susceptibility, electron spin resonance (ESR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The anti-diabetic effect of VC was investigated in comparison to vanadium sulfate in streptozotocin (STZ)-induced diabetic rats. Treatment of diabetic rats with VC versus vanadyl sulfate showed a more potent effect on reducing serum glucose and cholesterol close to normal levels. VC suppressed the diabetes-induced upregulation of hepatic glucose transporter (GLUT)-2, Phosphoenol pyruvate carboxykinase (PEPCK), and hormone-sensitive lipase (HSL) more significantly than vanadyl sulfate. Either vanadyl sulfate or VC restored hepatic sterol regulatory element-binding protein transcription factor-1c (SREBP-1c) and muscle hexokinase (HK) mRNA expression that was downregulated in diabetic group. Pyruvate kinase (PK) mRNA expression was restored more significantly in VC-treated than vanadyl sulfate-treated diabetic rats. These results indicate that the newly synthesized VC could be an effective anti-diabetic candidate as the anti-diabetic activity of the ionic vanadium was enhanced after being modified with the organic ligand, thiamin. The results also suggest that VC achieves its effect most likely through modulating the transcription of energy metabolizing enzymes.