JNK3 Perpetuates Metabolic Stress Induced by Aβ Peptides

Although Aβ peptides are causative agents in Alzheimer's disease (AD), the underlying mechanisms are still elusive. We report that Aβ42 induces a translational block by activating AMPK, thereby inhibiting the mTOR pathway. This translational block leads to widespread ER stress, which activates JNK3. JNK3 in turn phosphorylates APP at T668, thereby facilitating its endocytosis and subsequent processing. In support, pharmacologically blocking translation results in a significant increase in Aβ42 in a JNK3-dependent manner. Thus, JNK3 activation, which is?increased in human AD cases and a familial AD (FAD) mouse model, is integral to perpetuating Aβ42 production. Concomitantly, deletion of JNK3 from FAD mice results in a dramatic reduction in Aβ42 levels and overall plaque loads and increased neuronal number and improved cognition. This reveals AD as a metabolic disease that is under tight control by JNK3.     

A rapid method for the isolation of human peripheral null lymphocytes.

We describe here a new technique for the isolation of human peripheral null lymphocytes: cells lacking detectable surface immunoglobulin as well as receptors for sheep erythrocytes. The double rosette technique described employs a combined negative selection for Ig⁺ cells by specific anti-Ig-coated sheep erythrocytes and E rosette selection for T cells. This singlestep procedure facilitates the isolation of null cells from large cell populations and can be completed in less than 2 hr. The isolated null subpopulation represents less than 5% of the total peripheral mononuclear cells and is at least 85–90% pure by sensitive surface marker analysis. The null subpopulation is shown to be highly enriched for effectors of both antibody-dependent cytotoxicity against autologous lymphocytes and spontaneous cytotoxicity against the K562 leukemia blast cell line. Application of this technique will allow further characterization of the effector populations for ADCC and NK as well as differentiation of T and B cell precursors.     

Lymphocyte gamma-glutamyltranspeptidase activity in ataxia-telangiectasia

gamma-Glutamyltranspeptidase (GGTP) is a membrane-bound enzyme, that catalyzes gamma-glutamyl transfer from gamma-glutamyl compounds to amino acid and peptide acceptors. One of the most important clinical findings about ataxia-telangiectasia (A-T), a multisystemic and autosomal-recessive disease, is dysfunction of the immune system. In this study, the activity of GGTP was determined in the lymphocytes from patients with A-T. Lymphocyte GGTP activity in A-T patients was found to be significantly lower than that of control lymphocytes (P less than 0.001). This change may be due to the abnormality in the membrane of lymphocytes of A-T patients.     

Synthesis and Assembly of Simian Virus 40 I. Differential Synthesis of Intact Virions and Empty Shells

Intact virions and empty shells of simian virus 40 may be rapidly separated from each other and from cell contaminants by a procedure employing a CsCl cushion. This approach permits quantitation of their respective syntheses in infected cells labeled with radioactive amino acids. As much as 5 to 10% of the total acid-precipitable radioactive lysine in infected cell extracts was incorporated into viral particles in a two-hour pulse late in infection. Evidence for multiple origins of empty shells is presented. Some of the empty shells result from breakdown of intact virions. However, empty shells can also form independently of intact virions. First, labeling for periods of 15 min to 2 hr late in the course of infection results in preferential incorporation of (3)H-lysine into empty shells. Secondly, treatment with the deoxyribonucleic acid inhibitor cytosine-beta-d-arabinofuranoside late in infection results in a 50% inhibition in the rate of formation of intact virions with minimal reduction in the rate of appearance of empty shells.     

Evaluation of the gonial angle in the Anatolian populations: from past to present

Biometrical studies on ancient skeletal series and comparison with modern people by using radiological methods are quite limited in Turkey. Previous studies showed that measurements obtained from orthopantomographs are highly correlated with the actual size of the bones. The aim of the present study is to determine the possible change in gonial angle over time in ancient Anatolian populations with the present. Also an aim was attempted to demonstrate the symmetry of the gonial angle in the jaws and the sexual dimorphism. Gonial angle values (right and left) were taken from 267 Turkish adults with no craniomandibular disorders, orthodontic history or treatment by using panoramic radiographs. Data of the past populations were collected from previous studies. Comparison between right and left sides and the sexual differences were tested by paired student t-test and discriminant analyses were conducted. The results showed that there were no significant differences between the right and left gonial angles of the individuals but there was a significant difference at the left gonial angle between sexes (p < 0.01). Furthermore, no statistically significant difference was found for the gonial angle between the selected past populations with the present sample.     

Quantitative FRET Imaging to Visualize the Invasiveness of Live Breast Cancer Cells

Matrix metalloproteinases (MMPs) remodel tumor microenvironment and promote cancer metastasis. Among the MMP family proteases, the proteolytic activity of the pro-tumorigenic and pro-metastatic membrane-type 1 (MT1)-MMP constitutes a promising and targetable biomarker of aggressive cancer tumors. In this study, we systematically developed and characterized several highly sensitive and specific biosensors based on fluorescence resonant energy transfer (FRET), for visualizing MT1-MMP activity in live cells. The sensitivity of the AHLR-MT1-MMP biosensor was the highest and five times that of a reported version. Hence, the AHLR biosensor was employed to quantitatively profile the MT1-MMP activity in multiple breast cancer cell lines, and to visualize the spatiotemporal MT1-MMP activity simultaneously with the underlying collagen matrix at the single cell level. We detected a significantly higher level of MT1-MMP activity in invasive cancer cells than those in benign or non-invasive cells. Our results further show that the high MT1-MMP activity was stimulated by the adhesion of invasive cancer cells onto the extracellular matrix, which is precisely correlated with the cell’s ability to degrade the collagen matrix. Thus, we systematically optimized a FRET-based biosensor, which provides a powerful tool to detect the pro-invasive MT1-MMP activity at single cell levels. This readout can be applied to profile the invasiveness of single cells from clinical samples, and to serve as an indicator for screening anti-cancer inhibitors.     

Anti-inflammatory activity profile of JANEX-1 in preclinical animal models

We examined the biologic activity of the rationally designed JAK3 inhibitor, JANEX-1, in several cellular and animal models of inflammation. Notably, JANEX-1 exhibited potent anti-inflammatory activity in each of these preclinical models, including mouse models of peritonitis, colitis, cellulitis, and systemic inflammatory response syndrome. Therefore, JANEX-1 may prove useful as a broad-spectrum anti-inflammatory agent. The present study may provide the basis for new and effective treatment as well as prevention programs for inflammatory disorders.