Trypanosoma cruzi Presenilin-Like Transmembrane Aspartyl Protease: Characterization and Cellular Localization.

The increasing detection of infections of Trypanosoma cruzi, the etiological agent of Chagas disease, in non-endemic regions beyond Latin America has risen to be a major public health issue. With an impact in the millions of people, current treatments rely on antiquated drugs that produce severe side effects and are considered nearly ineffective for the chronic phase. The minimal progress in the development of new drugs highlights the need for advances in basic research on crucial biochemical pathways in T. cruzi to identify new targets. Here, we report on the T. cruzi presenilin-like transmembrane aspartyl enzyme, a protease of the aspartic class in a unique phylogenetic subgroup with T. vivax separate from protozoans. Computational analyses suggest it contains nine transmembrane domains and an active site with the characteristic PALP motif of the A22 family. Multiple linear B-cell epitopes were identified by SPOT-synthesis analysis with Chagasic patient sera. Two were chosen to generate rabbit antisera, whose signal was primarily localized to the flagellar pocket, intracellular vesicles, and endoplasmic reticulum in parasites by whole-cell immunofluorescence. The results suggest that the parasitic presenilin-like enzyme could have a role in the secretory pathway and serve as a target for the generation of new therapeutics specific to the T. cruzi.

[An overview of biomarkers in Alzheimer's disease].

Alzheimer's disease (AD), also called presenile dementia, is one of the most common neurodegenerative diseases in elderly people. The main pathological features of AD include senile plaques (SPs), neurofibrillary tangles (NFTs) and neuron loss. A biomarker is a characteristic that can be objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes, or pharmacological responses to a therapeutic intervention. Class biomarkers of AD such as Abeta and phosphorylated tau have been widely used in clinical diagnosis of AD patients. Recently, novel technologies like proteomics, genomics, and imaging techniques have expanded the role of a biomarker from early diagnosis to monitoring the progression of diseases and evaluating the response to various treatments. In this article, we will review the progress of various biomarkers of AD.

Isolation and characterization of the Drosophila ubiquilin ortholog dUbqln: in vivo interaction with early-onset Alzheimer disease genes.

UBQLN1 variants have been associated with increased risk for late-onset Alzheimer's disease (AD). We produced transgenic Drosophila models that either silence (by RNAi) or overexpress the Drosophila ortholog of human UBQLN1, dUbqln. Silencing of dUbqln in the central nervous system led to age-dependent neurodegeneration and shortened lifespan. Silencing of dUbqln in the wing led to wing vein loss that could be partially rescued by mutant rhomboid (rho), a known component of epidermal growth factor receptor signaling pathway. Conversely, overexpression of dUbqln promoted ecotopic wing veins. Overexpression of dUbqln in the eye rescued a small, rough eye phenotype induced by overexpression of Drosophila presenilin (dPsn), and also rescuing dPsn-induced malformations in bristles. In contrast, RNAi silencing of dUbqln enhanced the retinal degenerative defect induced by overexpression of dPsn. Finally, co-overexpression of dUbqln and the human amyloid precursor protein (APP) in the eye significantly reduced the levels of full-length APP and its C-terminal fragment. Collectively, these data support in vivo functional interaction between UBQLN1 and the AD-associated genes, presenilin and APP, and provide further clues regarding the potential role of UBQLN1 in AD pathogenesis.