Rama Shanker Verma

Bio: Rama Shanker Verma is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Mesenchymal stem cell & Stem cell. The author has an hindex of 30, co-authored 159 publications receiving 3160 citations. Previous affiliations of Rama Shanker Verma include University of Pennsylvania & Thapar University.

Characterization of electrospun fibrous scaffold produced from Indian eri silk fibroin

Abstract: A scaffold, synthesized from bio-degradable polymers and Bombyx mori silk fibroin in the form of films and fibrous assemblies, has been used as the bio-material for in-vivo applications. In the present work, the scaffold was prepared from the fibroin of Indian eri silk via the electrospinning method. The diameter of the fibre produced was in the range of 300 to 900 nm. The scaffold was subjected to ethanol treatment to improve its dimensional stability, as there was the problem of curling and shrinking when it was treated with solutions used for the cell culture. The scaffold was characterized for surface, thermal and tensile properties. The dimensional stability of the scaffold improved and the porosity reduced, due to the treatment of the scaffold with ethanol. The average failure stress of the raw and ethanol treated scaffold was 2.34 MPa and 4.91 MPa respectively and the mean strain was 13.63 % and 7.91 % respectively. Bone marrow stromal cells were isolated from the bone marrow of Swiss albi...

Nanobiotechnology: Application of Nanotechnology in Therapeutics and Diagnosis

Abstract: Nanobiotechnology is a recently coined term describing the convergence of the two existing but distant worlds of engineering and molecular biology. Nanobiotechnology is the interface between nanotechnology and biology. This is a combination of three words: NANO is tiny, BIO is living things, and TECHNOLOGY is about tools. It is an emerging area of scientific and technological advancement. Nanobiotechnology refers to the ability to create and manipulate biological and biochemical materials, devices, and systems at atomic and molecular levels (billionth of a meter). Thus, it is an integration of physical sciences, molecular engineering, biology, chemistry, and biotechnology, and holds considerable promise of advances in pharmaceuticals and health care. Nanomaterials are at the leading edge of the rapidly developing field of nanotechnology. Their unique size-dependent properties make these materials superior, indispensable in many areas of human activity, and above all a tiny tool to learn about liv...

Qualitative and quantitative detection of sodium deoxycholic acid in decellularized tissue

Abstract: Background Decellularization methods using anionic detergents have been applied to engineered tissues for eliminating tissue immunogenicity. Sodium deoxycholate is a water soluble ionic detergent commonly used in applications ranging from decellularisation, liposome preparation and isolation of membrane proteins and lipids. Sodium deoxycholate has been reported to form many reactive intermediates which bind to tissue and exert toxic effects.

In Vitro Hepatic Trans-Differentiation of Human Mesenchymal Stem Cells Using Sera from Congestive/Ischemic Liver during Cardiac Failure

Abstract: Cellular therapy for end-stage liver failures using human mesenchymal stem cells (hMSCs)-derived hepatocytes is a potential alternative to liver transplantation. Hepatic trans-differentiation of hMSCs is routinely accomplished by induction with commercially available recombinant growth factors, which is of limited clinical applications. In the present study, we have evaluated the potential of sera from cardiac-failure-associated congestive/ischemic liver patients for hepatic trans-differentiation of hMSCs. Results from such experiments were confirmed through morphological changes and expression of hepatocyte-specific markers at molecular and cellular level. Furthermore, the process of mesenchymal-to-epithelial transition during hepatic trans-differentiation of hMSCs was confirmed by elevated expression of E-Cadherin and down-regulation of Snail. The functionality of hMSCs-derived hepatocytes was validated by various liver function tests such as albumin synthesis, urea release, glycogen accumulation and presence of a drug inducible cytochrome P450 system. Based on these findings, we conclude that sera from congestive/ischemic liver during cardiac failure support a liver specific microenvironment for effective hepatic trans-differentiation of hMSCs in vitro.

Osteoblastic cells regulate the haematopoietic stem cell niche

Abstract: Stem cell fate is influenced by specialized microenvironments that remain poorly defined in mammals. To explore the possibility that haematopoietic stem cells derive regulatory information from bone, accounting for the localization of haematopoiesis in bone marrow, we assessed mice that were genetically altered to produce osteoblast-specific, activated PTH/PTHrP receptors (PPRs). Here we show that PPR-stimulated osteoblastic cells that are increased in number produce high levels of the Notch ligand jagged 1 and support an increase in the number of haematopoietic stem cells with evidence of Notch1 activation in vivo. Furthermore, ligand-dependent activation of PPR with parathyroid hormone (PTH) increased the number of osteoblasts in stromal cultures, and augmented ex vivo primitive haematopoietic cell growth that was abrogated by gamma-secretase inhibition of Notch activation. An increase in the number of stem cells was observed in wild-type animals after PTH injection, and survival after bone marrow transplantation was markedly improved. Therefore, osteoblastic cells are a regulatory component of the haematopoietic stem cell niche in vivo that influences stem cell function through Notch activation. Niche constituent cells or signalling pathways provide pharmacological targets with therapeutic potential for stem-cell-based therapies.

Reactive oxygen species in cell signaling

Abstract: Reactive oxygen species (ROS) are generated as by-products of cellular metabolism, primarily in the mitochondria. When cellular production of ROS overwhelms its antioxidant capacity, damage to cellular macromolecules such as lipids, protein, and DNA may ensue. Such a state of “oxidative stress” is thought to contribute to the pathogenesis of a number of human diseases including those of the lung. Recent studies have also implicated ROS that are generated by specialized plasma membrane oxidases in normal physiological signaling by growth factors and cytokines. In this review, we examine the evidence for ligand-induced generation of ROS, its cellular sources, and the signaling pathways that are activated. Emerging concepts on the mechanisms of signal transduction by ROS that involve alterations in cellular redox state and oxidative modifications of proteins are also discussed.

G1 events and regulation of cell proliferation.

Abstract: Cells prepare for S phase during the G1 phase of the cell cycle. Cell biological methods have provided knowledge of cycle kinetics and of substages of G1 that are determined by extracellular signals. Through the use of biochemical and molecular biological techniques to study effects of growth factors, oncogenes, and inhibitors, intracellular events during G1 that lead to DNA synthesis are rapidly being discovered. Many cells in vivo are in a quiescent state (G0), with unduplicated DNA. Cells can be activated to reenter the cycle during G1. Similarly, cells in culture can be shifted between G0 and G1. These switches in and out of G1 are the main determinants of post-embryonic cell proliferation rate and are defectively controlled in cancer cells.

Widespread requirement for Hedgehog ligand stimulation in growth of digestive tract tumours

Abstract: Activation of the Hedgehog (Hh) signalling pathway by sporadic mutations or in familial conditions such as Gorlin's syndrome is associated with tumorigenesis in skin, the cerebellum and skeletal muscle. Here we show that a wide range of digestive tract tumours, including most of those originating in the oesophagus, stomach, biliary tract and pancreas, but not in the colon, display increased Hh pathway activity, which is suppressible by cyclopamine, a Hh pathway antagonist. Cyclopamine also suppresses cell growth in vitro and causes durable regression of xenograft tumours in vivo. Unlike in Gorlin's syndrome tumours, pathway activity and cell growth in these digestive tract tumours are driven by endogenous expression of Hh ligands, as indicated by the presence of Sonic hedgehog and Indian hedgehog transcripts, by the pathway- and growth-inhibitory activity of a Hh-neutralizing antibody, and by the dramatic growth-stimulatory activity of exogenously added Hh ligand. Our results identify a group of common lethal malignancies in which Hh pathway activity, essential for tumour growth, is activated not by mutation but by ligand expression.