Activation of Hsp90-eNOS and increased NO generation attenuate respiration of hypoxia-treated endothelial cells

Hypoxia induces various adoptive signaling in cells that can cause several physiological changes. In the present work, we have observed that exposure of bovine aortic endothelial cells (BAECs) to extreme hypoxia (1-5% O(2)) attenuates cellular respiration by a mechanism involving heat shock protein 90 (Hsp90) and endothelial nitric oxide (NO) synthase (eNOS), so that the cells are conditioned to consume less oxygen and survive in prolonged hypoxic conditions. BAECs, exposed to 1% O(2), showed a reduced respiration compared with 21% O(2)-maintained cells. Western blot analysis showed an increase in the association of Hsp90-eNOS and enhanced NO generation on hypoxia exposure, whereas there was no significant accumulation of hypoxia-inducible factor-1alpha (HIF-1alpha). The addition of inhibitors of Hsp90, phosphatidylinositol 3-kinase, and NOS significantly alleviated this hypoxia-induced attenuation of respiration. Thus we conclude that hypoxia-induced excess NO and its derivatives such as ONOO(-) cause inhibition of the electron transport chain and attenuate O(2) demand, leading to cell survival at extreme hypoxia. More importantly, such an attenuation is found to be independent of HIF-1alpha, which is otherwise thought to be the key regulator of respiration in hypoxia-exposed cells, through a nonphosphorylative glycolytic pathway. The present mechanistic insight will be helpful to understand the difference in the magnitude of endothelial dysfunction.     

Cells as irreducible wholes: the failure of mechanism and the possibility of an organicist revival

According to vitalism, living organisms differ from machines and all other inanimate objects by being endowed with an indwelling immaterial directive agency, ‘vital force,’ or entelechy. While support for vitalism fell away in the late nineteenth century many biologists in the early twentieth century embraced a non vitalist philosophy variously termed organicism/holism/emergentism which aimed at replacing the actions of an immaterial spirit with what was seen as an equivalent but perfectly natural agency—the emergent autonomous activity of the whole organism. Organicists hold that organisms unlike machines are ‘more than the sum of their parts’ and predict that the vital properties of living things can never be explained in terms of mechanical analogies and that the reductionist agenda is doomed to failure. Here we review the current status of the mechanist and organicist conceptions of life particularly as they apply to the cell. We argue that despite the advances in biological knowledge over the past six decades since the molecular biological revolution, especially in the fields of genetics and cell biology the unique properties of living cells have still not been simulated in mechanical systems nor yielded to reductionist—analytical explanations. And we conclude that despite the dominance of the mechanistic–reductionist paradigm through most of the past century the possibility of a twentyfirst century organicist revival cannot be easily discounted.     

Micromanipulation of culture niche permits long-term expansion of dental pulp stem cells—an economic and commercial angle

Stem cells isolated from dental pulp possess the capacity for self-renewal and the potential for multi-lineage differentiation. However, dental pulp stem cells have different characteristics in terms of their culture conditions. The success of stem cells culture is governed by its micro-environmental niche. Therefore, we studied the effects of culture niche on long-term expansion of dental pulp stem cells in terms of cell morphology, growth kinetics, senescence pattern, cell surface marker expression differentiation capacity, and seeding plating density of dental pulp stem cells in four different, widely used media composition Among the various basal media tested, α-minimum essential media and knock out-minimum essential media supplemented with 10% fetal bovine serum were found to be the most optimal media composition in preserving the phenotypic characteristics and differentiation potential for prolonged periods as compared with DMEM-F12 and DMEM-LG. Plating density has been shown to affect overall yield. As a conclusion, the adoption of an appropriate culture system significantly improved cell yield, thus enabling the attainment of sufficient yields for therapeutic applications economizing in terms of cost of production and minimizing seeding cell density for maximum yield.     

Landscape mapping of functional proteins in insulin signal transduction and insulin resistance: a network-based protein-protein interaction analysis

The type 2 diabetes has increased rapidly in recent years throughout the world. The insulin signal transduction mechanism gets disrupted sometimes and it's known as insulin-resistance. It is one of the primary causes associated with type-2 diabetes. The signaling mechanisms involved several proteins that include 7 major functional proteins such as INS, INSR, IRS1, IRS2, PIK3CA, Akt2, and GLUT4. Using these 7 principal proteins, multiple sequences alignment has been created. The scores between sequences also have been developed. We have constructed a phylogenetic tree and modified it with node and distance. Besides, we have generated sequence logos and ultimately developed the protein-protein interaction network. The small insulin signal transduction protein arrangement shows complex network between the functional proteins.     

A Genome Wide Study of Copy Number Variation Associated with Nasopharyngeal Carcinoma in Malaysian Chinese Identifies CNVs at 11q14.3 and 6p21.3 as Candidate Loci

Background

Nasopharyngeal carcinoma (NPC) is a neoplasm of the epithelial lining of the nasopharynx. Despite various reports linking genomic variants to NPC predisposition, very few reports were done on copy number variations (CNV). CNV is an inherent structural variation that has been found to be involved in cancer predisposition.

Methods

A discovery cohort of Malaysian Chinese descent (NPC patients, n = 140; Healthy controls, n = 256) were genotyped using Illumina^® HumanOmniExpress BeadChip. PennCNV and cnvPartition calling algorithms were applied for CNV calling. Taqman CNV assays and digital PCR were used to validate CNV calls and replicate candidate copy number variant region (CNVR) associations in a follow-up Malaysian Chinese (NPC cases, n = 465; and Healthy controls, n = 677) and Malay cohort (NPC cases, n = 114; Healthy controls, n = 124).

Results

Six putative CNVRs overlapping GRM5, MICA/HCP5/HCG26, LILRB3/LILRA6, DPY19L2, RNase3/RNase2 and GOLPH3 genes were jointly identified by PennCNV and cnvPartition. CNVs overlapping GRM5 and MICA/HCP5/HCG26 were subjected to further validation by Taqman CNV assays and digital PCR. Combined analysis in Malaysian Chinese cohort revealed a strong association at CNVR on chromosome 11q14.3 (P_combined = 1.54x10^-5; odds ratio (OR) = 7.27; 95% CI = 2.96–17.88) overlapping GRM5 and a suggestive association at CNVR on chromosome 6p21.3 (P_combined = 1.29x10^-3; OR = 4.21; 95% CI = 1.75–10.11) overlapping MICA/HCP5/HCG26 genes.

Conclusion

Our results demonstrated the association of CNVs towards NPC susceptibility, implicating a possible role of CNVs in NPC development.     

Structurally mapping the diverse phenotype of adeno-associated virus serotype 4

The adeno-associated viruses (AAVs) can package and deliver foreign DNA into cells for corrective gene delivery applications. The AAV serotypes have distinct cell binding, transduction, and antigenic characteristics that have been shown to be dictated by the capsid viral protein (VP) sequence. To understand the contribution of capsid structure to these properties, we have determined the crystal structure of AAV serotype 4 (AAV4), one of the most diverse serotypes with respect to capsid protein sequence and antigenic reactivity. Structural comparison of AAV4 to AAV2 shows conservation of the core beta strands (betaB to betaI) and helical (alphaA) secondary structure elements, which also exist in all other known parvovirus structures. However, surface loop variations (I to IX), some containing compensating structural insertions and deletions in adjacent regions, result in local topological differences on the capsid surface. These include AAV4 having a deeper twofold depression, wider and rounder protrusions surrounding the threefold axes, and a different topology at the top of the fivefold channel from that of AAV2. Also, the previously observed "valleys" between the threefold protrusions, containing AAV2's heparin binding residues, are narrower in AAV4. The observed differences in loop topologies at subunit interfaces are consistent with the inability of AAV2 and AAV4 VPs to combine for mosaic capsid formation in efforts to engineer novel tropisms. Significantly, all of the surface loop variations are associated with amino acids reported to affect receptor recognition, transduction, and anticapsid antibody reactivity for AAV2. This observation suggests that these capsid regions may also play similar roles in the other AAV serotypes.     

Biochemical studies on hypoglycemic effect of Aavirai kudineer: a herbal formulation in alloxan diabetic rats

Aavirai Kudineer (AK) is an herbal decoction of seven botanical drugs, cited in the Gunapadam; a Tamil Siddha medical text. The anti-diabetic efficacy of this formulation was evaluated using alloxan-induced diabetic and normal rats. Glucose tolerance was observed within 1 hr in AK-treated rats (10 ml/kg body ) as compared to control. A significant decrease in the severe hyperglycemia characteristic of alloxan diabetes was noted after 15 days of AK treatment. Further AK treatment reversed the elevated urea, creatinine, cholesterol and decreased protein values to near normal levels. Assay of glycogen content and chief carbohydrate-metabolizing enzymes, viz. hexokinase, glucose-6-phosphatase and fructose 1,6 diphosphatase in the liver of diabetic and AK-treated diabetic rats clearly ascertains the hypoglycemic efficacy of this formulation. The mode of action of this herbal formulation remains to be elucidated.