Effect of serum cholesterol on the mRNA content of amyloid precursor protein in rat livers

The profile of β-amyloid precursor protein expression of rats induced by aluminum

The environmental agent aluminum has been extensively investigated for a potential relationship with amyloid precursor protein (APP) expression. Despite many investigations, there is at present no definite proof from which to draw a conclusion. Since APP is an integral membrane protein expressed in different tissues and capable of fluxes across the blood-brain barrier (BBB), which may ultimately affect APP level in brain, it is necessary to assess the expression profile among vital body organs. The present study compared aluminum oxide and aluminum chloride injected rats with control rats (saline treated) to observe if aluminum affected APP expression patterns in different organs by immunohistochemistry (IHC). The expression of APP was observed in the brain of aluminum chloride treated rats and in the liver of aluminum oxide injected group. Results of double IHC staining showed that it is Kupffer cells, which are located in liver sinus and expressed APP after aluminum oxide treatment. Oxidative stress is suggested as the potential pathway that aluminum chloride exert effects in brain. These results suggest that different aluminum compounds may impact the expression of APP in brain and liver tissues. The mechanism that aluminum induced liver APP expression still needs further investigation.

Dose-responsive gene expression changes in juvenile and adult mummichogs (Fundulus heteroclitus) after arsenic exposure

The present study investigated arsenic's effects on mummichogs (Fundulus heteroclitus), while also examining what role that gender or exposure age might play. Adult male and female mummichogs were exposed to 172 ppb, 575 ppb, or 1720 ppb arsenic as sodium arsenite for 10 days immediately prior to spawning. No differences were noted in the number or viability of eggs between the groups, but there was a significant increase in deformities in 1720 ppb arsenic exposure group. Total RNA from adult livers or 6-week old juveniles was used to probe custom macroarrays for changes in gene expression. In females, 3% of the genes were commonly differentially expressed in the 172 and 575 ppb exposure groups compared to controls. In the males, between 1.1 and 3% of the differentially expressed genes were in common between the exposure groups. Several genes, including apolipoprotein and serum amyloid precursor were commonly expressed in either a dose-responsive manner or were dose-specific, but consistent across genders. These patterns of regulation were confirmed by QPCR. These findings will provide us with a better understanding of the effects of dose, gender, and exposure age on the response to arsenic.