A novel role for Bruton's tyrosine kinase in hepatocyte growth factor-mediated immunoregulation of dendritic cells

The limited success of dendritic cell (DC)-based immunotherapy in multiple myeloma is partly due to hepatocyte growth factor (HGF)-induced DC dysfunction. From a therapeutic standpoint, it is important to understand the molecular events involved in inhibition of DC activation/maturation by HGF. Because Bruton's tyrosine kinase (Btk) negatively regulates maturation and immunostimulatory function of DCs, a role for Btk in HGF-induced inhibition of both murine and human DCs was investigated. We demonstrate that Btk is a novel proximal component of HGF-induced c-MET (HGF receptor) signaling. Following HGF treatment, Btk binds to c-MET and becomes activated. Btk activation in turn blocks the NF-κB pathway and subsequent DC activation via the c-Src-PI3K-AKT-mammalian target of rapamycin (mTOR) pathway. Notably, Btk activation is necessary for HGF-induced association of c-Src and PI3K with c-MET. Furthermore, we provide the first evidence that HGF inhibits DC activation by inducing autocrine interleukin (IL)-10 secretion, which requires activation of Btk. Blocking activation of Btk and its downstream the c-Src-PI3K-AKT-mTOR pathway prevents HGF-induced IL-10 secretion by DCs. In addition, neutralization of IL-10 secretion from DCs impaired the inhibitory effect of HGF on DCs. Thus, our study identifies a novel role for Btk in HGF-induced DC inhibition.     

Chromosome number, male meiosis and pollen fertility in selected angiosperms of the cold deserts of Lahaul-Spiti and adjoining areas (Himachal Pradesh, India)

In this study the exact chromosome number, detailed meiotic behavior in pollen mother cells and pollen viability were investigated, which can contribute to a better understanding of the cytological evolution of the species growing in the cold deserts of Lahaul-Spiti (Himachal Pradesh, India). This study is the first such comprehensive attempt to explore the region chromosomally. Chromosome number, meiotic behavior and pollen fertility were analyzed in 301 accessions of 140 species of Polypetalae. Chromosome counts in 14 species are the first ever records, viz., Aquilegia pubiflora (n?=?7), Corydalis govaniana (n?=?8), C. thyrsiflora (n?=?8), Hedysarum astragaloides (n?=?7), H. microcalyx (n?=?7), Oxytropis thomsoni (n?=?8), Rhodiola tibetica (n?=?10), R. wallichianum (n?=?16), Rosularia alpestris (n?=?14), Epilobium chitralense (n?=?18), E. leiospermum (n?=?18), Heracleum brunonis (2n?=?33), H. thomsonii (n?=?11) and Pleurospermum govanianum (n?=?9). New intraspecific diploid or polyploid cytotypes have been recorded in 13 species. The species of these cold deserts are quite active in evolution, depicting heterogeneity in chromosome number involving polyploidy, 51 species (36.43%) and/or aneuploidy (37 species). Various meiotic abnormalities were observed in the majority of the species, causing pollen sterility and pollen grains of variable sizes. We are of the opinion that harsh climatic conditions have caused various meiotic abnormalities in the majority of the plants, which has affected the genetic constitution and viability of male gametes.     

Differential interactions of fluorescent agonists and antagonists with the yeast G protein coupled receptor Ste2p

We describe a rapid method to probe for mutations in cell surface ligand-binding proteins that affect the environment of bound ligand. The method uses fluorescence-activated cell sorting to screen randomly mutated receptors for substitutions that alter the fluorescence emission spectrum of environmentally sensitive fluorescent ligands. When applied to the yeast α-factor receptor Ste2p, a G protein-coupled receptor, the procedure identified 22 substitutions that red shift the emission of a fluorescent agonist, including substitutions at residues previously implicated in ligand binding and at additional sites. A separate set of substitutions, identified in a screen for mutations that alter the emission of a fluorescent α-factor antagonist, occurs at sites that are unlikely to contact the ligand directly. Instead, these mutations alter receptor conformation to increase ligand-binding affinity and provide signaling in response to antagonists of normal receptors. These results suggest that receptor-agonist interactions involve at least two sites, of which only one is specific for the activated conformation of the receptor.     

Multifarious plant growth promoting characteristics of chickpea rhizosphere associated Bacilli help to suppress soil-borne pathogens

Wilt and root rot are the major constraints in chickpea production and very difficult to manage through agrochemicals. Hence, for an ecofriendly and biological management, 240 strains of Bacillus and Bacillus derived genera were isolated from chickpea rhizosphere, further narrowed down to 14 strains on the basis of in vitro production of indole acetic acid, siderophore, phosphate solubilization, hydrolytic enzymes and were evaluated for antagonism against chickpea pathogens (Fusarium oxysporum f. sp. ciceri race 1, F. solani and Macrophomina phaseolina). The strains were identified on the basis of physiological characters and 16S RNA gene sequencing. The genotypic comparisons of strains were determined by BOX-polymerase chain reaction profiles and amplified rDNA restriction analysis. These isolates were evaluated in greenhouse assay in which B. subtilis (B-CM191, B-CV235, B-CL-122) proved to be effective in reducing wilt incidence and significant enhancement in growth (root and shoot length) and dry matter of chickpea plants. PCR amplification of bacillomycin (bmyB) and β-glucanase genes suggests that amplified genes from the Bacillus could have a role to further define the diversity, ecology, and biocontrol activities in the suppression of soil-borne pathogens.     

Enhanced stability of alcohol dehydrogenase by non-covalent interaction with polysaccharides

Non-covalent interaction of alcohol dehydrogenase with polysaccharides was studied using three neutral and three anionic polysaccharides. The process of interaction of alcohol dehydrogenase with gum Arabic was optimized with respect to the ratio of enzyme to gum Arabic, pH, and molarity of buffer. Alcohol dehydrogenase–gum Arabic complex formed under optimized conditions showed 93 % retention of original activity with enhanced thermal and pH stability. Lower inactivation rate constant of alcohol dehydrogenase–gum Arabic complex within the temperature range of 45 to 60 °C implied its better stability. Half-life of alcohol dehydrogenase–gum Arabic complex was higher than that of free alcohol dehydrogenase. A slight increment was observed in kinetic constants (K _m and V _max) of gum Arabic-complexed alcohol dehydrogenase which may be due to interference by gum Arabic for the binding of substrate to the enzyme. Helix to turn conversion was observed in complexed alcohol dehydrogenase as compared to free alcohol dehydrogenase which may be responsible for observed stability enhancement.     

Molecular cloning,sequence characterization and recombinant expression of Nanog gene in goat fibroblast cells using lentiviral based expression system

Nanog is a homeodomain containing protein which plays important roles in regulation of signaling pathways for maintenance and induction of pluripotency in stem cells. Because of its unique expression in stem cells it is also regarded as pluripotency marker. In this study goat Nanog (gNanog) gene has been amplified, cloned and characterized at sequence level with successful over-expression in CHO-K1 cell line using a lentiviral based system. gNanog ORF is 903 bp long which codes for Nanog protein of size 300 amino acids (aas). Complete nucleotide sequence shows some evolutionary mutation in goat in comparision to other species. Protein sequence of goat is highly similar to other species. Overall, gNanog nucleotide sequence and predicted protein sequence showed high similarity and minimum divergence with cattle (96 % identity/4 % divergence) and buffalo (94/5 %) while low similarity and high divergence with pig (84/15 %), human (81/23 %) and mouse (69/40 %) indicating evolutionary closeness of gNanog to cattle and buffalo. gNanog lentiviral expression construct was prepared for over-expression of Nanog gene in adult goat fibroblast cells. Lentiviral expression construct of Nanog enabled continuous protein expression for induction and maintenance of pluripotency. Western blotting revealed the expression of Nanog gene at protein level which supported that the lentiviral expression system is highly promising for Nanog protein expression in differentiated goat cell.     

Cytomorphological diversity in some selected members of Poaceae from Parvati Valley in Kullu district of Himachal Pradesh,India

The present work includes detailed male meiotic studies on 46 species of grasses falling into 59 accessions from different localities of Parvati Valley in Kullu district of Himachal Pradesh in the altitudinal range of 1,100 to 2,750 m. All the species have been studied cytologically for the first time from the study area. The meiotic chromosome count of n = 14 for Calamagrostis emodensis is the first ever chromosome report. Three species, namely Agrostis alba (n = 21), Avena byzantina (n = 21) and Bromus inermis (n = 14) have been studied cytologically for the first time from India. New intraspecific diploid/polyploid cytotypes have been reported for Arthraxon serrulatus (2n = 4x = 32), Iseilema laxum (2n = 12x = 60), Digitaria albudens (2n = 8x = 72), Festuca kashmiriana (2n = 2x = 14) and Stipa orientalis (2n = 2x = 20). The existence of variable number of B-chromosomes (2n = 60 + 0-5B) has been reported for the first time in the 12x cytotype of Iseilema laxum. Secondary associations of chromosomes in the tetraploid cytotype of Cymbopogon martini (n = 20) indicated its secondary polyploid nature. As many as 18 species showed various meiotic anomalies such as the phenomenon of cytomixis involving inter PMC migration of chromatin material, chromatin stickiness, interbivalent connections, abnormal spindle activity, presence of bridges and laggards during anaphases and telophases and abnormal sporads. These meiotic abnormalities consequently yielded sterile and heterogeneous-sized fertile pollen grains. The polyploidy and aneuploidy have played an active role in the evolution of grasses.     

Micronutrient Deficiency and Treatment Adherence in a Randomized Controlled Trial of Micronutrient Supplementation in ART-Na?ve Persons with HIV

Introduction

The MAINTAIN study is an on-going RCT comparing high-dose micronutrient and anti-oxidant supplementation versus recommended daily allowance (RDA) vitamins in slowing HIV immune deficiency progression in ART-naïve people with HIV infection.

Objective

We planned analysis of the first 127 participants to determine the baseline prevalence of serum micronutrient deficiencies and correlates, as well as tolerance and adherence to study interventions.

Methods

Participants receive eight capsules twice daily of 1) high-dose or 2) RDA supplements for two years and are followed-up quarterly for measures of immune deficiency progression, safety and tolerability. Regression analysis was used to identify correlates of micronutrient levels at baseline. Adherence was measured by residual pill count, self-report using the General Treatment Scale (GTS) and short-term recall HIV Adherence Treatment Scale (HATS).

Results

Prior micronutrient supplementation (within 30 days) was 27% at screening and 10% of study population, and was not correlated with baseline micronutrient levels. Low levels were frequent for carotene (24%<1 nmol/L), vitamin D (24%<40 nmol/L) and serum folate (20%<15 nmol/L). The proportion with B₁₂ deficiency (<133 pmol/L) was 2.4%. Lower baseline levels of B₁₂ correlated lower baseline CD4 count (r = 0.21, p = 0.02) with a 21 pmol/L reduction in B₁₂ per 100 cells/µL CD4. Vitamin D levels were higher in men (p<0.001). After a median follow-up of 1.63 years, there were 19 (15%) early withdrawals from the study treatment. Mean treatment adherence using pill count was 88%. Subjective adherence by the GTS was 81% and was moderately but significantly correlated with pill count (r = 0.29, p<0.001). Adherence based on short-term recall (HATS) was >80% in 75% of participants.

Conclusion

Micronutrient levels in asymptomatic HIV+ persons are in keeping with population norms, but micronutrient deficiencies are frequent. Adherence levels are high, and will permit a valid evaluation of treatment effects.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00798772","term_id":"NCT00798772"}}NCT00798772     

LR-90 prevents methylglyoxal-induced oxidative stress and apoptosis in human endothelial cells

Methylglyoxal (MGO) is a highly reactive dicarbonyl compound known to induce cellular injury and cytoxicity, including apoptosis in vascular cells. Vascular endothelial cell apoptosis has been implicated in the pathophysiology and progression of atherosclerosis. We investigated whether the advanced glycation end-product inhibitor LR-90 could prevent MGO-induced apoptosis in human umbilical vascular endothelial cells (HUVECs). HUVECs were pre-treated with LR-90 and then stimulated with MGO. Cell morphology, cytotoxicity and apoptosis were evaluated by light microscopy, MTT assay, and Annexin V-FITC and propidium iodide double staining, respectively. Levels of Bax, Bcl-2, cytochrome c, mitogen-activated protein kinases (MAPKs) and caspase activities were assessed by Western blotting. Reactive oxygen species (ROS) generation and mitochondrial membrane potential (MMP) were measured with fluorescent probes. LR-90 dose-dependently prevented MGO-associated HUVEC cytotoxicity and apoptotic biochemical changes such as loss of MMP, increased Bax/Bcl-2 protein ratio, mitochondrial cytochrome c release and activation of caspase-3 and 9. Additionally, LR-90 blocked intracellular ROS formation and MAPK (p44/p42, p38, JNK) activation, though the latter seem to be not directly involved in MGO-induced HUVEC apoptosis. LR-90 prevents MGO-induced HUVEC apoptosis by inhibiting ROS and associated mitochondrial-dependent apoptotic signaling cascades, suggesting that LR-90 possess cytoprotective ability which could be beneficial in prevention of diabetic related-atherosclerosis.