Structural transition in micelles: novel insight into microenvironmental changes in polarity and dynamics

Structural transitions involving shape changes play an important role in cellular physiology. Such transition can be conveniently induced in charged micelles by increasing ionic strength of the medium. Shape changes have recently been shown to result in altered packing and lowering of micellar polarity. As a consequence of reduced polarity, the ionization states of micelle-bound molecules vary in micelles of different shape. The changes in micellar organization and dynamics due to structural transition can be effectively monitored utilizing the red edge excitation shift (REES). These changes are influenced by the position (location) of the probe in the micelle, i.e., the region of the micelle being monitored. Changes in organization and dynamics of probes and peptides upon structural transition are discussed with representative examples. We envisage that the reduction in micellar polarity and tighter packing upon structural transition represent important factors in the incorporation of drugs in micelles (nano-carriers), since micellar polarity plays a crucial role in the incorporation of drugs.     

Intricacies of hedgehog signaling pathways: a perspective in tumorigenesis

The hedgehog (HH) signaling pathway is a crucial negotiator of developmental proceedings in the embryo governing a diverse array of processes including cell proliferation, differentiation, and tissue patterning. The overall activity of the pathway is significantly curtailed after embryogenesis as well as in adults, yet it retains many of its functional capacities. However, aberration in HH signaling mediates the initiation, proliferation and continued sustenance of malignancy in different tissues to varying degrees through different mechanisms. In this review, we provide an overview of the role of constitutively active aberrant HH signaling pathway in different types of human cancer and the underlying molecular and genetic mechanisms that drive tumorigenesis in that particular tissue. An insight into the various modes of anomalous HH signaling in different organs will provide a comprehensive knowledge of the pathway in these tissues and open a window for individually tailored, tissue-specific therapeutic interventions. The synergistic cross talking of HH pathway with many other regulatory molecules and developmentally inclined signaling pathways may offer many avenues for pharmacological advances. Understanding the molecular basis of abnormal HH signaling in cancer will provide an opportunity to inhibit the deregulated pathway in many aggressive and therapeutically challenging cancers where promising options are not available.     

Micropropagation of Withania coagulans (Stocks) Dunal: A Critically Endangered Medicinal Herb

An efficient micropropagation protocol has been developed for Withania coagulans, a highly endangered medicinal herb and an important natural source of withanolides. Prolific multiplication of axillary buds occurred from the nodal segments taken from adult plant, and cultured on MS medium enriched with BA (0.5 mg l^?1), Kn (0.5 mg l^?1) and PG (0.5 mg l^?1). Nodal segments and shoot tips of elongated microshoots also behaved the same way in cultures and formed multiple shoots through axillary bud multiplication. Addition of PG (0.5 mg l^?1) in the regeneration medium significantly improved induction and elongation of shoot buds. Elongated shoots were placed on filter paper bridges soaked in MS medium with CC (10 mg l^?1) and PG (0.5 mg l^?1) for the initial 7 days’ pulse treatment and thereafter, they were transferred to rooting medium containing IBA (0.25 mg l^?1) + PAA (0.5 mg l^?1) + CC (2 mg l^?1). This protocol has the capacity of producing 1000 plants from one nodal segment after 4 subcultures of 2 weeks each.     

Virus-induced gene silencing: A versatile tool for discovery of gene functions in plants

Virus-induced gene silencing (VIGS) is a technology that exploits an antiviral defense mechanism in plants as a tool for plant reverse genetics. VIGS circumvents the need for plant transformation, is methodologically simple and yields rapid results. Various VIGS vectors have been developed and have helped to unravel the functions of genes involved in processes such as disease resistance, abiotic stress, cellular signaling and secondary metabolite biosynthesis.     

Inflammatory mediators and the failing heart: a translational approach

Recent studies have identified the importance of proinflammatory mediators in regulating cardiac structure in health and disease. Recent studies suggest that cytokines that are expressed within the myocardium in response to a environmental injury, namely tumor necrosis factor-alpha (TNF), interleukin-1 (IL-1) and the interleukin-6 (IL-6) family of cytokines play an important role in initiating and integrating homeostatic responses within the heart. However, these "stress-activated" cytokines all have the potential to produce cardiac decompensation when expressed at sufficiently high concentrations. Indeed, there is now a growing appreciation that these molecules may play an important role in mediating disease progression in the failing heart. The growing appreciation of the pathophysiological consequences of sustained expression of proinflammatory mediators in pre-clinical and clinical heart failure models culminated in a series of multicenter clinical trials that utilized "targeted" approaches to neutralize tumor necrosis factor (TNF) in patients with moderate to advanced heart failure. However, these targeted approaches have resulted in worsening heart failure, thereby raising a number of important questions about what role, if any, proinflammatory cytokines play in the pathogenesis of heart failure. This review will summarize the tremendous growth of knowledge that has taken place in this field, with a focus on what we have learned from the negative clinical trials, as well as the potential direction of future research in this area.     

The role of free radicals in cold injuries

Cold injury is a tissue trauma produced by exposure to freezing temperatures and even brief exposure to a severely cold and windy environment. Rewarming of frozen tissue is associated with blood reperfusion and the simultaneous generation of free oxygen radicals. In this review is discussed the current understanding of the mechanism of action of free oxygen radicals as related to cold injury during rewarming. Decreased energy stores during ischaemia lead to the accumulation of adenine nucleotides and liberation of free fatty acids due to the breakdown of lipid membranes. On rewarming, free fatty acids are metabolized via cyclo-oxygenase and adenine nucleotides are metabolized via the xanthine oxidase pathway. These may be the source of free oxygen radicals. Leukocytes may also play a major role in the pathogenesis of cold injury. Oxygen radical scavengers, such as superoxide dismutase and catalase, may help to reduce the cold induced injury but their action is limited due to the inability readily to cross the plasma membrane. Lipid soluble antioxidants are likely to be more effective scavengers because of their presence in membranes where peroxidative reactions can be arrested.     

In-Silico and In-Vitro Analysis of Human SOS1 Protein Causing Noonan Syndrome - A Novel Approach to Explore the Molecular Pathways

AimsPerform in-silico analysis of human SOS1 mutations to elucidate their pathogenic role in Noonan syndrome (NS).BackgroundNS is an autosomal dominant genetic disorder caused by single nucleotide mutation in PTPN11, SOS1, RAF1, and KRAS genes. NS is thought to affect approximately 1 in 1000. NS patients suffer different pathogenic effects depending on the mutations they carry. Analysis of the mutations would be a promising predictor in identifying the pathogenic effect of NS.MethodsWe performed computational analysis of the SOS1 gene to identify the pathogenic nonsynonymous single nucleotide polymorphisms (nsSNPs) th a t cause NS. SOS1 variants were retrieved from the SNP database (dbSNP) and analyzed by in-silico tools I-Mutant, iPTREESTAB, and MutPred to elucidate their structural and functional characteristics.ResultsWe found that 11 nsSNPs of SOS1 that were linked to NS. 3D modeling of the wild-type and the 11 nsSNPs of SOS1 showed that SOS1 interacts with cardiac proteins GATA4, TNNT2, and ACTN2. We also found that GRB2 and HRAS act as intermediate molecules between SOS1 and cardiac proteins. Our in-silico analysis findings were further validated using induced cardiomyocytes (iCMCs) derived from NS patients carrying SOS1 gene variant c.1654A>G (NSiCMCs) and compared to control human skin fibroblast-derived iCMCs (C-iCMCs). Our in vitro data confirmed that the SOS1, GRB2 and HRAS gene expressions as well as the activated ERK protein, were significantly decreased in NS-iCMCs when compared to C-iCMCs.ConclusionThis is the first in-silico and in vitro study demonstrating that 11 nsSNPs of SOS1 play deleterious pathogenic roles in causing NS.