The mechanism of action of citrinin on rabbit kidney alkaline phosphatase activity in vivo.

The effect of citrinin poisoning on rabbit kidney alkaline phosphatase was investigated. After seven days administration of citrinin (2 mg/kg body weight daily) the animals were sacrificed and the level of enzymes estimated in serum and kidney. Serum enzymes showed no variation in activity in the citrinin-treated animals, but in kidney, alkaline phosphatase activity decreased significantly. The decreased activity was mainly associated with the cytoplasmic fraction and in fractions Ib and II. The enzyme II obtained from citrinin-treated animal showed no kinetic difference in substrate specificity, inhibition by phenylalanine, phosphate, sodium-EDTA and Zn2+ ions, activation by Mg2+ ions, thermal inactivation and electrophoretic mobility to that of control Enzyme II. Immunological studies showed that the decrease in enzyme activity was due to existence of inactive enzyme protein. Hormones like cyclic AMP, prostaglandin E1 and parathyroid hormone reversed the decreased enzyme activity due to citrinin poisoning in mouse and rabbit. This study favours the possible existence of active and inactive forms of alkaline phosphatase in the system.     

Diagnostic utility of APOE, soluble CD40, CD40L, and Abeta1-40 levels in plasma in Alzheimer's disease

A continuous inflammatory state is associated with Alzheimer's disease (AD) evidenced by an increase in proinflammatory cytokines around beta-amyloid (Abeta) deposits. In addition, functional loss of CD40L is shown to result in diminished Amyloid precursor proton (APP) processing and microglial activation, supporting a prominent role of CD40-CD40L in AD etiology. We therefore hypothesize that a peripheral increase in Abeta may result in corresponding increase of sCD40 and sCD40L further contributing to AD pathogenesis. We measured plasma Abeta, sCD40 and sCD40L levels in 73 AD patients and compared to 102 controls matched on general demographics. We demonstrated that Abeta(1-40), levels of sCD40 and sCD40L are increased in AD and declining MMSE scores correlated with increasing sCD40L, which in turn, correlated positively with Abeta(1-42). We then combined sCD40, sCD40L, Abeta and APOE and found that this biomarker panel has high sensitivity and specificity (>90%) as a predictor of clinical AD diagnosis. Given the imminent availability of potentially disease modifying therapies for AD, a great need exists for peripheral diagnostic markers of AD. Thus, we present preliminary evidence for potential usefulness for combination of plasma sCD40, sCD40L along with Abeta(1-40) and APOE epsilon4 in improving the clinical diagnosis of AD.     

Coimmunization with an optimized IL-15 plasmid results in enhanced function and longevity of CD8 T cells that are partially independent of CD4 T cell help

DNA vaccines are a promising technology for the induction of Ag-specific immune responses, and much recent attention has gone into improving their immune potency. In this study we test the feasibility of delivering a plasmid encoding IL-15 as a DNA vaccine adjuvant for the induction of improved Ag-specific CD8(+) T cellular immune responses. Because native IL-15 is poorly expressed, we used PCR-based strategies to develop an optimized construct that expresses 80-fold higher than the native IL-15 construct. Using a DNA vaccination model, we determined that immunization with optimized IL-15 in combination with HIV-1gag DNA constructs resulted in a significant enhancement of Ag-specific CD8(+) T cell proliferation and IFN-gamma secretion, and strong induction of long-lived CD8(+) T cell responses. In an influenza DNA vaccine model, coimmunization with plasmid expressing influenza A PR8/34 hemagglutinin with the optimized IL-15 plasmid generated improved long term CD8(+) T cellular immunity and protected the mice against a lethal mucosal challenge with influenza virus. Because we observed that IL-15 appeared to mostly adjuvant CD8(+) T cell function, we show that in the partial, but not total, absence of CD4(+) T cell help, plasmid-delivered IL-15 could restore CD8 secondary immune responses to an antigenic DNA plasmid, supporting the idea that the effects of IL-15 on CD8(+) T cell expansion require the presence of low levels of CD4 T cells. These data suggest a role for enhanced plasmid IL-15 as a candidate adjuvant for vaccine or immunotherapeutic studies.     

APDbase: Amino acid Physico-chemical properties Database

Physico-chemical properties of amino acids can be used to study protein sequence profiles, folding and function. We collated 242 properties for the 20 naturally occurring amino acids and created a dataset. The dataset is available as a database named APDbase( Amino acid Physico-chemical properties Data base). The database can be queried using either key words describing physico-chemical properties or pre-assigned database index number. The database contains corresponding references for each property value and facilitates deposition of new property values for processing and inclusion in the database.

Availability     

Synthesis,crystal and antibacterial studies of diversely functionalized tetrahydropyridin-4-ol

In an effort to expand the spectrum of antibacterial activity associated with piperidin-4-one derivatives, we have synthesized two series of 3-carboxyethyl-2,6-diphenyl-4-hydroxy-Δ³-tetrahydropyridine derivatives bearing diversified heterocyclic and aromatic systems at the nitrogen atom through acetyl (6–18) and 2-propanoyl (9–31) linkers. Unlike acetyl derivatives, NMR spectral pattern of the propanoyl counterparts revealed the existence of pair of rotational isomers (syn and anti) in solution at room temperature due to the hindered rotation about N–CO bond. X-ray crystal studies of 9 and 24 clearly pointed out that all the compounds existed in only one form particularly, in stable syn form in solid state. Each of the compounds was screened for their in vitro antibacterial activity against nine human pathogenic Gram-positive strains including multiple drug resistant organisms and seven problematic Gram-negative strains. Among the various heterocycles examined here, imidazole substituted derivatives 12 and 25 exhibited antibacterial activity approaching that of Linezolid and Trovafloxacin drugs particularly against multiple resistant Enterococcus faecium-VanA phenotype strains.     

Inducing protein-protein interactions with molecular glues

The drugable proteome is limited by the number of functional binding sites that can bind small molecules and respond with a therapeutic effect. Orthosteric and allosteric modulators of enzyme function or receptor signaling are well-established mechanisms of drug action. Drugs that perturb protein-protein interactions have only recently been launched. This approach is more difficult due to the extensive contact surfaces that must be perturbed antagonistically. Compounds that promote novel protein-protein interactions promise to dramatically expand opportunities for therapeutic intervention. This approach is precedented with natural products (rapamycin, FK506, sanglifehrin A), synthetic small molecules (thalidomide and IMiD derivatives) and indisulam analogues.     

Elevated mitochondrial activity distinguishes fibrogenic hepatic stellate cells and sensitizes for selective inhibition by mitotropic doxorubicin

Activation of hepatic stellate cells (HSCs) is an integral component of the wound‐healing process in liver injury/inflammation. However, uncontrolled activation of HSCs leads to constant secretion of collagen‐rich extracellular matrix (ECM) proteins, resulting in liver fibrosis. The enhanced ECM synthesis/secretion demands an uninterrupted supply of intracellular energy; however, there is a paucity of data on the bioenergetics, particularly the mitochondrial (mito) metabolism of fibrogenic HSCs. Here, using human and rat HSCs in vitro, we show that the mito‐respiration, mito‐membrane potential (Δψm) and cellular ‘bioenergetic signature’ distinguish fibrogenic HSCs from normal, less‐active HSCs. Ex vivo, HSCs from mouse and rat models of liver fibrosis further confirmed the altered ‘bioenergetic signature’ of fibrogenic HSCs. Importantly, the distinctive elevation in mito‐Δψm sensitized fibrogenic HSCs for selective inhibition by mitotropic doxorubicin while normal, less‐active HSCs and healthy human primary hepatocytes remained minimally affected if not, unaffected. Thus, the increased mito‐Δψm may provide an opportunity to selectively target fibrogenic HSCs in liver fibrosis.