Preclinical validation of a potent γ-secretase modulator for Alzheimer's disease prevention.

A potent γ-secretase modulator (GSM) has been developed to circumvent problems associated with γ-secretase inhibitors (GSIs) and to potentially enable use in primary prevention of early-onset familial Alzheimer's disease (EOFAD). Unlike GSIs, GSMs do not inhibit γ-secretase activity but rather allosterically modulate γ-secretase, reducing the net production of Aß42 and to a lesser extent Aß40, while concomitantly augmenting production of Aß38 and Aß37. This GSM demonstrated robust time- and dose-dependent efficacy in acute, subchronic, and chronic studies across multiple species, including primary and secondary prevention studies in a transgenic mouse model. The GSM displayed a >40-fold safety margin in rats based on a comparison of the systemic exposure (AUC) at the no observed adverse effect level (NOAEL) to the 50% effective AUC or AUCeffective, the systemic exposure required for reducing levels of Aß42 in rat brain by 50%.

Pulicaria vulgaris Gaertn. essential oil: an alternative or complementary treatment for Leishmaniasis.

Leishmaniasis is a neglected parasitic protozoal disease that affects approximately 12 million people and represents a public health problem in Iran. The objectives of this study were to obtain the essential oil (EO) from Pulicaria vulgaris Gaertn. growing in Iran and to carry out in-vitro antileishmanial screening of the EO against promastigotes of Leishmania major and Leishmania infantum. The EO from the aerial parts of P. vulgaris was extracted by hydrodistillation. Serial dilutions of the EO were screened for in-vitro antileishmanial activity using 96-well microtiter plates. The P. vulgaris EO was active against the promastigote forms of L. major and L. infantum, with IC50 values of 244.70 and 233.65 µg/mL, respectively. Pulicaria vulgaris EO may serve as an alternative or complementary treatment for leishmaniasis.

Increased Vulnerability of the Hippocampus in Transgenic Mice Overexpressing APP and Triple Repeat Tau.

Alzheimer's disease (AD) is the most common tauopathy, characterized by progressive accumulation of amyloid-ß (Aß) and hyperphosphorylated tau. While pathology associated with the 4-repeat (4R) tau isoform is more abundant in corticobasal degeneration and progressive supranuclear palsy, both 3R and 4R tau isoforms accumulate in AD. Many studies have investigated interactions between Aß and 4R tau in double transgenic mice, but few, if any, have examined the effects of Aß with 3R tau. To examine this relationship, we crossed our APP751 mutant line with our recently characterized 3R tau mutant model to create a bigenic line (hAPP-3RTau) to model AD neuropathology. Mice were analyzed at 3 and 6 months of age for pathological and behavioral endpoints. While both the 3RTau and the hAPP-3RTau mice showed neuronal loss, increased tau aggregation, Aß plaques and exhibited more behavioral deficits compared to the non-tg control, the bigenic mice often displaying relatively worsening levels. We found that even in young animals we found that the presence of APP/Aß increased the accumulation of 3R tau in the neocortex and hippocampus. This observation was accompanied by activation of GSK3 and neurodegeneration in the neocortex and CA1 region. These results suggest that in addition to 4R tau, APP/Aß may also enhance accumulation of 3R tau, a process which may be directly relevant to pathogenic pathways in AD. Our results demonstrate that this bigenic model closely parallels the pathological course of AD and may serve as a valuable model for testing new pharmacological interventions.