Ghrelin modulates intracellular signalling pathways that are critical for podocyte survival

Lebanese Cannabis sativa L. extract protects from cisplatin-induced nephrotoxicity in mice by inhibiting podocytes apoptosis

BACKGROUND

Cisplatin is an anti-cancer drug used to treat a plethora of solid tumors. However, it is associated with dose dependent nephrotoxicity limiting its use as anticancer agent.

OBJECTIVE

The current study aimed to investigate the nephroprotective effect of native Lebanese Cannabis sativa in both in vitro and in vivo mice model of cisplatin-induced nephrotoxicity.

METHODS

Podocytes cell viability was assessed using MTS assay with cisplatin (30µM) in presence or absence of Cannabis oil extract (COE) at 0.5, 1 and 2µg/ml for 24h. Acute renal injury was established in adult female C57BL/6 mice with 20mg/kg, i.p. single dose cisplatin. Mice were divided into control group (vehicle), COE group, cisplatin group and cisplatin plus COE (2.5, 5 and 20mg/kg, i.p.). Animal body weight, serum creatinine, blood urea nitrogen (BUN), and proteinuria were measured.

RESULTS

Cell viability assay and western blot analysis revealed that COE prevented apoptosis induced by cisplatin in cultured immortalized rat podocytes. In addition, in vitro scratch assay demonstrated the ability of COE to promote and restore the migratory capacity of podocytes in cisplatin-treated cells. Interestingly, COE treatment improved urinary and serum parameters characterized by a significant decrease in serum creatinine, urea, and proteinuria at various COE doses. Western blot analysis showed that COE inhibited COX-2 protein induction as well as apoptosis marker production (Bax/Bcl2 ratio) in cisplatin-treated mice when compared to mice treated with cisplatin alone.

CONCLUSION

Collectively, the aforementioned findings indicate that COE could be a promising approach to protect against cisplatin-induced nephrotoxicity.

Lebanese cannabis oil extract protected against folic acid-induced kidney fibrosis in rats

BACKGROUND

Renal fibrosis is a major manifestation of chronic kidney disease. To date, there are no treatments to reverse kidney fibrosis. Cannabis is an aromatic herb that is widely known for its anti-diabetic and anti-inflammatory properties. The aim of this study is to evaluate the protective effect of Lebanese cannabis oil extract (COE) against folic acid (FA) induced renal injury both in vitro and in vivo.

MATERIALS AND METHODS

A single dose of 250 mg/kg of Folic acid was administered to induce renal fibrosis in rats. COE was injected at varying doses of 5, 10, and 20 mg/kg. Body weight of rats were monitored and clinical parameters including serum creatinine, urea, and electrolytes were measured. Moreover, pathological examination of the kidney and heart was performed. Conditionally immortalized cultured rat podocytes were exposed to high concentrations of folic acid in the presence or absence of COE. MTS and in vitro scratch assay were used to assess podocyte cells viability and migration respectively. Western blot analysis was used to evaluate the phosphorylation levels of AKT and p38 MAPK.

RESULTS

Rats that received FA showed a marked increase in serum creatinine when compared to the non-treated control group. COE at doses of 5 and 10 mg/kg significantly decreased serum creatinine induced by FA. Serum sodium was significantly reduced in all the groups receiving COE. Furthermore, COE ameliorated renal and cardiac pathology abnormalities caused by FA in a dose-dependent manner. Cell viability assay revealed that COE reversed cytotoxicity induced by FA in rat podocytes. In vitro scratch assay showed that COE partially restored the migratory capacity of podocytes incubated with FA. Dose-dependent experiments showed that COE (1 and 2μg/ml) induced a significant increase of phospho-(S473)-AKT along with a decrease in phospho (T180 + Y182) P38 levels.

CONCLUSION

The current results revealed important protective effect of Lebanese cannabis oil extract against folic acid-induced renal fibrosis in rats.

Ghrelin hormone a new molecular modulator between obesity and glomerular damage

The incidence of glomerular diseases is increasing worldwide due to increased prevalence of obesity which is a major risk factor for type-2 diabetes mellitus and cardiovascular disorders.Ghrelin, an orexigenic peptide hormone, has been implicated in obesity, and its impact on the pathology and function of the kidneys was found to be significant. Ghrelin known to regulate energy homeostasis and growth hormone release, has been shown to modulate critical signaling pathways involved in the health and survival of podocytes. These derangements directly affect glomerular function and manifest as impaired glomerular filtration barrier and leakage of albumin into urine. Although the pathological features of the above-mentioned disorders are different, they interestingly lead to similar clinical features of glomerular damage. The pathological events are majorly initiated by endocrine imbalance leading to abnormal activation of downstream signaling pathways involved in the development of glomerulosclerosis. In fact, obesity increases the risk of developing chronic kidney disease by altering the secretion of pro-inflammatory cytokines and adipokines, activating the renin-angiotensin-aldosterone system (RAAS), promoting lipotoxicity, oxidative stress and fibrosis within the kidneys. Whilst these bioregulators are well described, their direct involvement in renal homeostasis is still mostly elusive. This review summarized previous and recent evidence on the endocrine properties of ghrelin and perivascular adipose tissue involved in modulating kidney physiology.

Drivers of Research Outcomes in Developing Countries: The Case of Lebanon

This paper uses a unique dataset from Lebanon, a developing country with unstable political conditions, to explore the drivers of research outcomes. We use the Negative Binomial model to empirically examine the determinants of the total number of publications and single and co-authored articles. The results indicate that males are more likely to publish co-authored papers than females. Moreover, our findings show a quadratic relationship between age and the number of published papers with a peak at the age of 40. After this turning point, the publication rate starts to decrease at an increasing rate. When we run the model by gender, we find that females in large departments tend to publish more co-authored papers. We also find that full professors tend to publish more papers in Q1 and Q2 journals, while associate professors have more papers in Q2 and Q3 journals.

Mechanisms Underlying the Biological Effects of Molecular Hydrogen

Aberrant redox-sensitive reactions and accumulation of oxidative damage can impair body functions and contribute to the development of various pathologies and aging. Although antioxidant substances have long been recognized as a measure of alleviating oxidative stress and restoring redox balance, the arsenal of effective means of preventing the development of various disorders, is still limited. There is an emerging field that utilizes molecular hydrogen (H₂) as a scavenger of free radicals and reactive oxygen species (ROS). Among the remarkable characteristics of H₂ is its ability to counteract the harmful effects of hydroxyl radical and peroxynitrite without affecting the activity of functionally important ROS, such as hydrogen peroxide and nitric oxide. The beneficial effects of H₂ have been documented in numerous clinical studies and studies on animal models and cell cultures. However, the established scavenging activity of H₂ can only partially explain its beneficial effects because the effects are achieved at very low concentrations of H₂. Given the rate of H₂ diffusion, such low concentrations may not be sufficient to scavenge continuously generated ROS. H₂ can also act as a signaling molecule and induce defense responses. However, the exact targets and mechanism(s) by which H₂ exerts these effects are unknown. Here, we analyzed both positive and negative effects of the endogenous H₂, identified the redox-sensitive components of the pathways affected by molecular hydrogen, and also discussed the potential role of molecular hydrogen in regulating cellular redox.

The selective anti-proliferative and pro-apoptotic effect of A. cherimola on MDA-MB-231 breast cancer cell line

Background

Herbal medicines have been a major target for numerous studies through the past years as an alternative treatment for cancer, mainly due to their minimal effects on normal healthy cells. Annona cherimola, popularly known as Cherimoya, is an edible natural fruit rich in phytochemical components and known to possess various biological activities. Previous studies have reported the anti-cancerous effect of A. cherimola ethanolic leaf extract (AELE) on leukemia. This study aims at studying the potential anti-cancer activity of this extract in vitro in two different breast cancer cell lines, namely MDA-MB-231 and MCF-7, in addition to investigating its toxicity on normal mesenchymal stem cells.

Methods

The anti-proliferative effect of AELE was evaluated via cell viability assay. Propidium iodide staining, Cell Death Detection ELISA and flow cytometry analysis of Annexin V binding were used to assess cell cycle progression, DNA fragmentation and apoptosis induction, respectively. Protein expression was determined via Western Blot analysis to decipher the underlying apoptotic molecular mechanism induced upon AELE treatment.

Results

The anti-proliferative effect of the extract was found to be selective on the triple-negative breast cancer cell line (MDA-MB-231) in a time- and dose-dependent manner with an IC₅₀ of 390.2 μg/mL at 48 h, with no cytotoxic effects on normal murine mesenchymal stem cells. The pro-apoptotic effect was confirmed by the increase in cellular and DNA fragmentation, flipping of the phosphatidylserine moiety to the outer leaflet, and the increase in Annexin V binding. The underlying molecular mechanism revealed the involvement of the mitochondrial pathway, as shown by alterations in mitochondrial permeability and the upregulation of cytochrome c expression.

Conclusion

All the data presented in our study suggest that AELE exhibits a selective anti-proliferative and pro-apoptotic effect on the chemo-resistant MDA-MB-231 breast cancer cells, providing evidence for the anti-tumor effects of A. cherimola.

Ghrelin-induced multi-organ damage in mice fed obesogenic diet

OBJECTIVE AND DESIGN

Ghrelin has a key role in modulating energy metabolism and weight gain. The present study aimed at studying the potential role of ghrelin in the development and/or exacerbation of organ damage in a mouse model of diet-induced obesity.

OBJECTIVE AND DESIGN

Adult mice were fed one of two diets for 20 weeks: standard high carbohydrate (HC) or high-fat high-sugar (HFHS). Starting week 17, the animals were given regular intraperitoneal ghrelin (160 µg/kg) or saline injections Abdominal fat, serum creatinine, and glucose levels, as well as kidney, liver and heart weight and pathology were assessed.

RESULTS

Ghrelin-injected mice showed significant organ damage, which was more exacerbated in HFHS-fed animals. While the HFHS diet was associated with significant liver damage, ghrelin administration did not reverse it. Interestingly, ghrelin administration induced moderate kidney damage and significantly affected the heart by increasing perivascular and myocardium fibrosis, steatosis as well as inflammation. Moreover, serum creatinine levels were higher in the animal group injected with ghrelin.

CONCLUSION

Ghrelin administration was associated with increased functional and structural organ damage, regardless of diet. The present study provides novel evidence of multi-organ physiologic alterations secondary to ghrelin administration.