Differential dysregulation of CREB and synaptic genes in transgenic Drosophila melanogaster expressing shaggy (GSK3), TauWT, or Amyloid-beta.

BACKGROUND: Tau, Amyloid-beta (Aß42), and Glycogen synthase kinase 3 (GSK3) contribute to synaptic dysfunction observed in Alzheimer's disease (AD), the most common form of dementia. In the current study, the effect of pan-neuronal expression of TauWT, Aß42, or shaggy (orthologue of GSK3) in Drosophila melanogaster was assessed on the locomotor function, ethanol sensitivity, synaptic genes and CREB expression. The effect of TauWT and Aß42 on the expression of shaggy was also determined. METHODS AND RESULTS: Gene expression analysis was performed using quantitative real-time RT-PCR method. While syt1, SNAP25 and CREB (upstream transcription factor of syt1 and SNAP25) were upregulated in flies expressing TauWT or Aß42, a prominent decline was observed in those genes in shaggy expressing flies. Although all transgenic flies showed climbing disability and higher sensitivity to ethanol, abnormality in these features was significantly more prominent in transgenic flies expressing shaggy compared to TauWT or Aß42. Despite a significant upregulation of shaggy transcription in TauWT expressing flies, Aß42 transgenic flies witnessed no significant changes. CONCLUSIONS: TauWT, Aß42, and shaggy may affect synaptic plasticity through dysregulation of synaptic genes and CREB, independently. However shaggy has more detrimental effect on synaptic genes expression, locomotor ability and sensitivity to ethanol. It is important when it comes to drug discovery. It appears that CREB is a direct effector of changes in synaptic genes expression as they showed similar pattern of alteration and it is likely to be a part of compensatory mechanisms independent of the GSK3/CREB pathway in TauWT or Aß42 expressing flies.

Berberis integerrima hydro-alcoholic root extract and its constituent berberine protect against cisplatin-induced nephro- and hepato-toxicity.

BACKGROUND: This study determined the potential hepato- and renal protective role of berberine and hydroalcohol extract of Berberis integerrima (barberry) against cisplatin-induced acute liver and kidney injury. METHODS: Animals were dedicated into six groups (n = 7 per group): control, control+Ber (berberine, 0.4 mg/kg/day during 10 days, i.p.), control+B.E (barberry extract, 160 mg/kg/day during 10 days, i.p.), Cis (cisplatin, 8 mg/kg on 7th day, i.p.), Cis+Ber (berberine, 100 mg/kg/day during 10 days; cisplatin, 8 mg/kg on 7th day), Cis+B.E (barberry extract, 160 mg/kg/day during 10 days; cisplatin, 8 mg/kg on 7th day). After placing the rats in metabolic cages for 24 h, blood, urine, liver and kidney tissue samples were collected. RESULTS: Compared to control, control+Ber and control+B.E groups, cisplatin administration led to kidney and liver dysfunction. These happened with diminished activities of antioxidant enzymes, increased levels of malondialdehyde, Toll-like receptor 4 gene expression and histological damages in hepatic and renal tissues. Berberine and barberry extract administration decreased all the changes. CONCLUSIONS: An intensification in enzymatic oxidant status, decrease in lipid peroxidation with decrease in TLR4 gene expression level indicate that barberry extract may be a potential candidate in combating cisplatin-induced oxidative stress and inflammation in liver and kidney tissues through its constituent berberine.