Ghrelin modulates intracellular signalling pathways that are critical for podocyte survival.

Damage to podocytes is a key event in glomerulopathies. While energy dense food can contribute to kidney damage, the role of the orixegenic hormone "ghrelin" in podocyte biology is still unknown. In the present study, we investigated the effect of ghrelin on podocyte survival as well as the signalling pathways mediating ghrelin effect in immortalized cultured rat podocytes. RT-PCR analysis revealed that GHS-R1 is expressed in rat podocytes. Western blot analysis showed that ghrelin upregulated COX-2 protein expression in a time and dose-dependent manner. Additionally, ghrelin activated P38 MAPK, AKT, and ERK1/2 pathways and also induced P38 MAPK phosphorylation in high glucose conditions. Ghrelin induced ROS release and dose dependently reduced podocyte survival. Ghrelin mediated podocyte cell death was partially reversed by pharmacologically inhibiting P38 MAPK or phospholipase C (PLC). Furthermore, PLC inhibitor (U73122) inhibited ghrelin induced P38 MAPK activation. While PI3K inhibitor (LY294002) was without effect on cell survival or P38 MAPK activation, it inhibited ghrelin induced ERK1/2 phosphorylation. Finally, ghrelin induced TAU phosphorylation was reversed by pharmacologic inhibitors of either P38 MAPK or PKA. In conclusion, ghrelin activated harmful molecular pathways in podocytes that can be damaging to the glomerular filtration barrier SIGNIFICANCE OF THE STUDY: Endocrine derangements secondary to obesity are major players in the aetiology of renal injuries. Furthermore, energy dense diet is thought to be the major element in developing obesity. Appetite and increase in energy intake are regulated by complex hormonal pathways which mainly include the orexigenic hormone "ghrelin" in addition to leptin. To date no study have highlighted a significant role for ghrelin in kidney biology, and therefore, it is thought that its endocrine effect is mostly limited to adipose tissue metabolism and appetite regulation. In this study, we first showed that ghrelin receptor is expressed on glomerular podocytes. Also, ghrelin showed negative impact on podocyte survival through modulating signalling pathways such as P38 MAPK and AKT known to play a key role in podocyte health. Moreover, the negative effects of ghrelin on podocytes were further exacerbated in hyperglycemic conditions. Of note, podocytes contribute to the formation and the maintenance of the glomerular filtration barrier and thus are important for normal renal function. Therefore, ghrelin secretion in the context of obesity could be involved in the aetiology of kidney injury, a well-known hallmark found in obese patients.

Transforming growth factor-ß1 and phosphatases modulate COX-2 protein expression and TAU phosphorylation in cultured immortalized podocytes.

OBJECTIVE AND DESIGN: The aim of this study is to elucidate TGF-ß1 signaling pathways involved in COX-2 protein induction and modulation of TAU protein phosphorylation in cultured podocytes. MATERIALS, TREATMENT AND METHODS: In vitro cultured immortalized podocytes were stimulated with TGF-ß1 in presence and absence of pharmacologic inhibitors for various signaling pathways and phosphatases. Then, COX-2 protein expression, as well as P38MAPK, AKT and TAU phosphorylation levels were evaluated by western blot analysis. RESULTS: TGF-ß1 induction of COX-2 protein levels was completely blocked by pharmacologic inhibitors of phosphatases, P38 MAPK, or NF-қB pathways. Time course experiments showed that TGF-ß1 activated p38 MAPK after 5 min of stimulation. Interestingly, podocyte co-incubated with TGF-ß1, high glucose and/or PGE2 showed strong increase in p38 MAPK and AKT phosphorylation as well as COX- 2 protein expression levels. Levels of phosphorylated AKT were further reduced and levels of phosphorylated p38 were increased when PGE2 was added to the culture media. Interestingly, selective phosphatases inhibitors completely abrogated PGE2-induced P38 MAPK and TAU phosphorylation. Also, inhibition of phosphatases reversed TGF-ß1-induced COX-2 protein expression either alone or when incubated with high glucose or PGE2. CONCLUSION: These data suggest TGF-ß1 mediates its effect in podocyte through novel signaling mechanisms including phosphatases and TAU protein phosphorylation.

Salvia libanotica improves glycemia and serum lipid profile in rats fed a high fat diet.

BACKGROUND: Salvia libanotica (S. Libanotica) is a commonly used herb in folk medicine in Lebanon and the Middle East. The present study aimed to assess the scientific basis for the therapeutic use of S. libanotica in glycemia and to evaluate its effects on lipemia and abdominal fat. METHODS: Animals were fed a high-fat diet and allocated into a control and three experimental groups (GI, GII and GIII) receiving incremental doses of the plant water extract in drinking water (50, 150 and 450 mg/Kg body weight respectively) for six weeks. RESULTS: The intake of S. libanotica extract was associated with a significant decrease in fasting serum glucose (102.9 ± 10.8 in GII and 87.5 ± 6.4 in GIII vs. 152.1 ± 7.9 mg/dl in controls) and a two fold increase in fasting serum insulin (GIII) and liver glycogen content (GII and GIII). Group III also had better glucose tolerance following intraperitoneal glucose challenges. Additionally, the plant extract intake produced a significant improvement in serum HDL (34.4 ± 2.4 in GIII vs. 27.2 ± 1.9 mg/dl in controls) and HDL/LDL cholesterol ratio (2.79 ± 0.32 in GII and 3.02 ± 0.31 in GIII vs. 1.74 ± 0.18 in controls), as well as a decrease in abdominal fat. CONCLUSION: The current study is the first to demonstrate that the chronic intake of S. libanotica infusion helps in the prevention of high fat-induced hyperglycemia and dyslipidemia. This supports the plant use as a remedy for the prevention of type 2 diabetes and cardiovascular diseases.

Magnetic property, DFT calculation, and biological activity of bis[(µ(2)-chloro)chloro(1,10-phenanthroline)copper(II)] complex.

The dinuclear complex bis[(µ(2)-chloro)chloro(1,10-phenanthroline)copper(II)] (1) was synthesized, and characterized by X-ray, FTIR and thermal analysis. The fitting of magnetic susceptibility and magnetization curve of (1) indicates the occurrence of weak antiferromagnetic exchange interaction between copper(II) ions. The electronic structure has been also determined by density functional theory (DFT) method. Complex (1) displayed potent anticancer activity against B16 (Melanoma), MDA-MB-32 (Breast Adenocarcinoma), A549 (Lung Adenocarcinoma), HT-29 (Colon Adenocarcinoma) and SF (Astrocytoma) cell lines with an average IC50 value of 0.726 µg/ml compared to 4.88 µg/ml for cisplatin. Complex (1) has a better therapeutic index and toxicological profile than cisplatin, and has demonstrated a potential chemotherapeutic property.

Wild carrot oil extract is selectively cytotoxic to human acute myeloid leukemia cells.

BACKGROUND: In this study, we used Daucus carota oil extract (DCOE) to target acute myeloid leukemia (AML) cells. All the AML cell lines tested were sensitive to the extract while peripheral mononuclear cells were not. Analysis of mechanism of cell death showed an increase in cells positive for annexinV and for active caspases, indicating that DCOE induces apoptotic cell death in AML. Inhibition of the MAPK pathway decreased sensitivity of AML cells to DCOE, indicating that cytotoxicity may be dependent on its activity. In conclusion, DCOE induces selective apoptosis in AML cells, possibly through a MAPK-dependent mechanism.

Daucus carota pentane-based fractions arrest the cell cycle and increase apoptosis in MDA-MB-231 breast cancer cells.

BACKGROUND: Daucus carota L.ssp.carota (wild carrot), an herb used in folk medicine worldwide, was recently demonstrated to exhibit anticancer activity. In this study we examined the anticancer effect of Daucus carota oil extract (DCOE) fractions on the human breast adenocarcinoma cell lines MDA-MB-231 and MCF-7 and clarified the mechanism of action. METHODS AND RESULTS: Using the WST assay, the pentane fraction (F1) and 1:1 pentane:diethyl ether fraction (F2) were shown to possess the highest cytotoxicity against both cell lines. Flow cytometric analysis revealed that both fractions induced the accumulation of cells in the sub-G1 phase, increase in apoptotic cell death and chromatin condensation. The increase in apoptosis in response to treatment was also apparent in the increase in BAX and the decrease in Bcl-2 levels as well as the proteolytic cleavage of both caspase-3 and PARP as revealed by Western blot. Furthermore, treatment of MDA-MB-231 cells with either fraction significantly reduced the level of phosphorylated Erk but did not show any effect on phosphorylated Akt. The combined treatment with a potent PI3K inhibitor (wortmannin) and F1 or F2 fraction had a synergistic inhibitory effect on cell survival which shows that these two drugs work on different pathways. CONCLUSIONS: These results suggest that the pentane-based fractions of DCOE possess potential anti-cancer activity that is mainly mediated through the Erk pathway.

Prophylaxis with ertapenem in patients with obstructive jaundice undergoing endoscopic retrograde cholangiopancreatography: safety, efficacy, and biliary penetration.

BACKGROUND: Cholangitis and biliary sepsis are rare but serious complications of endoscopic retrograde cholangiopancreatography (ERCP). The aim of this study is to investigate the safety, efficacy, and biliary penetration of ertapenem, a newer carbapenem with a long half-life and broad-spectrum antimicrobial activity, for ERCP prophylaxis. METHODS: Patients with obstructive jaundice without cholangitis received a single dose of ertapenem equal to 1 gram intravenously prior to ERCP. A 2-3 mL bile sample was collected after cannulation and prior to contrast injection. Patients were observed for 72 hours for cholangitis or drug-related adverse events. Biliary ertapenem levels were measured using high-performance liquid chromatography (HPLC). RESULTS: Twenty-eight patients (ages 18-87 years, M/F ratio 1:1) were enrolled. Seven had no cholestasis and were included to study ertapenem penetration in unobstructed biliary trees. Cannulation was achieved in all patients. One patient (3.6%) with persistent intrahepatic stones developed cholangitis. No drug-related adverse events were noted. The mean time from ertapenem administration to bile collection was 60 ± 24 minutes. There was a significant negative correlation between serum bilirubin and biliary ertapenem levels (r = -0.542, P = 0.003) with the highest level (6.25 µg/mL) noted in unobstructed biliary systems. CONCLUSION: Ertapenem appears to be a safe and effective prophylaxis in patients with obstructive jaundice undergoing ERCP despite a limited biliary penetration in patients with high-grade obstruction.