siRNA Blocking of Mammalian Target of Rapamycin (mTOR) Attenuates Pathology in Annonacin-Induced Tauopathy in Mice.

Tauopathy is a pathological hallmark of many neurodegenerative diseases. It is characterized by abnormal aggregates of pathological phosphotau and somatodendritic redistribution. One suggested strategy for treating tauopathy is to stimulate autophagy, hence, getting rid of these pathological protein aggregates. One key controller of autophagy is mTOR. Since stimulation of mTOR leads to inhibition of autophagy, inhibitors of mTOR will cause stimulation of autophagy process. In this report, tauopathy was induced in mice using annonacin. Blocking of mTOR was achieved through stereotaxic injection of siRNA against mTOR. The behavioral and immunohistochemical evaluation revealed the development of tauopathy model as proven by deterioration of behavioral performance in open field test and significant tau aggregates in annonacin-treated mice. Blocking of mTOR revealed significant clearance of tau aggregates in the injected side; however, tau expression was not affected by mTOR blockage.

Toll-like receptor 4 blocker as potential therapy for acetaminophen-induced organ failure in mice.

Acetaminophen (APAP, 4-hydroxyacetanilide) is the most common cause of acute liver failure in the United States. In addition to exhibiting hepatotoxicity, APAP exerts a nephrotoxic effect may be independent of the induced liver damage. Toll-like receptors (TLRs) have been suggested as a potential class of novel therapeutic targets. The aim of the present study was to investigate the potential of the TLR-4 blocker TAK-242 in the prevention of APAP-induced hepato-renal failure. Four groups of C57BL mice were studied: Vehicle-treated/control (VEH), APAP-treated (APAP), N-acetyl cysteine (NAC)-pretreated plus APAP (APAP + NAC) and TAK-242-pretreated plus APAP (APAP + TAK) groups. Mice were clinically assessed then perfused 4 h later. Liver and kidney tissues were collected and examined histologically using basic hematoxylin and eosin staining to detect signs of necrosis and inflammation. Plasma samples were collected to measure the levels of alanine transaminase, aspartate transaminase and serum creatinine. In addition, liver and kidney tissues were assayed to determine the levels of reduced glutathione. The results of the present study indicate the potential role of TLR-4 in APAP-induced organ toxicity. In the APAP + TAK and APAP + NAC groups, histopathological examination indicated that pretreatment with TAK-242 or NAC afforded protection against APAP-induced injury. However, this protective effect was more clinically evident in the APAP + TAK group compared with the APAP + NAC group. The various biochemical parameters (serum enzymes and reduced glutathione) revealed no significant protection in either of the pretreated groups. Therefore, the present study indicated that the TLR-4 blocker had protective effects against acute APAP toxicity in liver and kidney tissues. These effects were identified clinically, histologically and biochemically. Furthermore, the TLR-4 blocker TAK-242 exhibited antioxidant properties in addition to anti-inflammatory effects.