ABSTRACT
<p><b>OBJECTIVE</b>To review recent research advances on tau, a major player in Alzheimer's disease (AD) pathogenesis, a biomarker for AD onset, and potential target for AD therapy.</p><p><b>DATA SOURCES</b>This review was based on a comprehensive search using online literature databases, including PubMed, Web of Science, and Google Scholar.</p><p><b>STUDY SELECTION</b>Literature search was based on the following keywords: Alzheimer's disease, tau protein, biomarker, cerebrospinal fluid (CSF), therapeutics, plasma, imaging, propagation, spreading, seeding, prion, conformational templating, and posttranslational modification. Relevant articles were carefully reviewed, with no exclusions applied to study design and publication type.</p><p><b>RESULTS</b>Amyloid plaques enriched with extracellular amyloid beta (Aβ) and intracellular neurofibrillary tangles comprised of hyperphosphorylated tau proteins are the two main pathological hallmarks of AD. Although the Aβ hypothesis has dominated AD research for many years, clinical Aβ-targeting strategies have consistently failed to effectively treat AD or prevent AD onset. The research focus in AD has recently shifted to the role of tau in AD. In addition to phosphorylation, tau is acetylated and proteolytically cleaved, which also contribute to its physiological and pathological functions. Emerging evidence characterizing pathological tau propagation and spreading provides new avenues for research into the molecular and cellular mechanisms underlying AD pathogenesis. Techniques to detect tau at minute levels in CSF and blood have been developed, and improved tracers have facilitated tau imaging in the brain. These advances have potential to accurately determine tau levels at early diagnostic stages in AD. Given that tau is a potential therapeutic target, anti-tau immunotherapy may potentially be a viable treatment strategy in AD intervention.</p><p><b>CONCLUSION</b>Detecting changes in tau and targeting tau pathology represent a promising lead in the diagnosis and treatment of AD.</p>
ABSTRACT
Genetic mutations in triggering receptor expressed on myeloid cells 2 (TREM2) have been linked to a variety of neurodegenerative diseases including Alzheimer’s disease, amyotrophic lateral sclerosis, frontotemporal dementia and Parkinson’s disease. In the brain, TREM2 is highly expressed on the cell surface of microglia, where it can transduce signals to regulate microglial functions such as phagocytosis. To date, mechanisms underlying intracellular trafficking of TREM2 remain elusive. Mutations in the presenilin 1 (PS1) catalytic subunit of the γ-secretase complex have been associated with increased generation of the amyloidogenic Aβ (amyloid-β) 42 peptide through cleavage of the Aβ precursor amyloid precursor protein. Here we found that TREM2 interacts with PS1 in a manner independent of γ-secretase activity. Mutations in TREM2 alter its subcellular localization and affects its interaction with PS1. Upregulation of PS1 reduces, whereas downregulation of PS1 increases, steady-state levels of cell surface TREM2. Furthermore, PS1 overexpression results in attenuated phagocytic uptake of Aβ by microglia, which is reversed by TREM2 overexpression. Our data indicate a novel role for PS1 in regulating TREM2 intracellular trafficking and pathophysiological function.
ABSTRACT
This study was aimed to investigate the SLC25A38 expression in pediatric patients with acute lymphoblastic leukemia (ALL) and its clinical significance. A total of 23 newly diagnosed ALL pedictric patients were enrolled in test group, 10 pediatric patients with non-hematologic malignancies were selected as control group. The expression in protein and mRNA levels of SLC25A38 were detected by Western blot and real-time PCR respectively. The results showed that the SLC25A38 protein was positive in 8 of 23 pediatric ALL patients (34.78%), while no positive case was found in 10 controls. The relative expression level of SLC25A38 mRNA was 0.4673 ± 0.05344 in SLC25A38-protein positive group of ALL patients, while that was 1.296 ± 0.2517 in SLC25A38-protein negative group of ALL patients. The expression level of SLC25A38 mRNA in SLC25A38-protein positive group was significantly lower than that in negative group (P = 0.001) . No statistically significant difference was found in comparison of SLC25A38-protein negative group of ALL patients with the control group (P = 0.1097). The analysis of clinical data showed that there were significantly differences in sex, immunophenotype, initial peripheral white blood cell count and LDH between the SLC25A38-protein positive and SLC25A38-protein negative groups (P < 0.05). It is concluded that as a novel protein, SLC25A38 highly expressed in pediatric ALL patients, indicating that SLC25A38 may serve as a molecular marker and potential therapeutic target for acute lymphoblastic leukemia in children.