Vimal Singh - Profile on Academia.edu (original) (raw)

Papers by Vimal Singh

Academia Medicine, Jan 30, 2024

Cancer cells differ from healthy tissues in their biological makeup. Recent research reported vas... more Cancer cells differ from healthy tissues in their biological makeup. Recent research reported vast genetic and epigenetic heterogeneity, differences in the gene-expression profiles, and signal transduction networks in a broad range of cancers. These discoveries led to the development and clinical approval of several drugs that are more efficient and can specifically target cancer-specific pathways to provide a long-lasting cure. Recent advancements in describing genetic alterations in human cancers are a tempting reason for scientists to develop more effective, personalized therapies as the next level of cancer treatment. However, the drug discovery process is tedious, and getting approval from various regulatory authorities may be more frustrating for a steady developmental pace. Among various prime regulators, the most critical challenge and priority in oncology research is to define unique molecular biomarkers, which would enhance the diagnosis. These molecular biomarkers should have the potential to beacon the prognostics, design, and monitoring of the newer therapeutics. Several key findings are being identified to discover and validate such molecular biomarkers for their diagnostic potential at the DNA, RNA, and protein levels. Furthermore, noninvasive imaging technologies and serum biomarkers are promising higher quality outputs in a limited time which could be a useful tool to monitor early responses to the treatment and may be able to design the remedial course. These advances would pave the way for personalized cancer therapeutics if translated beyond scientific discovery. This article highlights the various aspects of translational research and associated issues i.e. trial design, tissue collection, and regulatory requirements.

International Journal of Science and Research (IJSR), 2016

Differentiation and proliferation of megakaryocytic progenitor cells into mature platelets is tri... more Differentiation and proliferation of megakaryocytic progenitor cells into mature platelets is triggered and activated upon binding of Thrombopoietin Receptor (TPOR), a cytokine receptor protein, to thrombopoietin (TPO), a 95 KD glycoprotein hormone.TPO plays a very important role as it can easily direct Hematopoietic Progenitor Cells into the megakaryocytic lineage but even then very few mimetic have been reported, Agonists such as Romiplostim and Electrombopag are reported, recombinant TPO mimetic are also available but structural mimetic is only TMP, so the scope of further research is available. A promising approach for designing a mimetic can be targeting the binding site of the receptor such that the mimetic peptide has similar agonist activity as the ligand. Diverse libraries can be created using in-silico approaches and they are analyzed to bind receptor efficiently. In this study efforts are made for the development of TPO mimetic with therapeutic potential. TPO increases its number, prevent apoptosis, and thereby increases platelet production. Activation of TPO receptor leads to phosphorylation of the cytoplasmic domain as well as downstream activation of JAK2, STAT5, and other anti-apoptotic pathways. This increases the viability of stem cells and precursors of all lineages. The anti-apoptotic effect of TPO is probably important in patients with ITP: bone marrow megakaryocytes and megakaryocyte precursors are already increased but these cells are undergoing apoptosis mediated by anti-platelet IgG and T cells, thereby limiting platelet production. Administration of TPO decreases the apoptotic rate of the megakaryocyte precursors and thereby enhance the platelet production. Once produced, platelets are still affected by TPO. TPO's new Combinatorial library was designed by interaction sites of TPOR with TPO and previously reported TPO mimetic peptide (TMP), further screening of combinatorial library was done and an efficient mimetic was chosen based on scoring function commonly called Energy. Energy is calculated in terms of KJ/mol, based on the orientations generated by docking ligand with the receptor, the most efficient ligand has the most stable conformation with minimum energy value. In this study docking of TPO and TPOR has a minimum energy value of-518.20; TPOR and mimetic designed has a total score of-456.55which is better than the known mimetic TMP, which has an energy score of-170.17 with TPOR. Computational approaches confirmed that the resulting peptide mimetic was stable and similar in nature to TPO. Further Ex-vivo study of designed mimetic can confirm its role in regenerative medicine, increasing the shelf life of platelet to improve cellular viability of platelet by preventing programmed cell death, i.e. apoptosis, which can be achieved by adding TPO during storage since TPO levels increase when platelet count is low, to stimulate additional production. TPO is absorbed by transfused platelets, which may decrease available TPO level or in the disease condition.

Frontiers in Medicine

Significant research revealed the preocular tear film composition and regulations that remain vit... more Significant research revealed the preocular tear film composition and regulations that remain vital for maintaining Ocular surface functional integrity. Inflammation triggered by many factors is the hallmark of Ocular surface disorders or dry eyes syndrome (DES). The tear deficiencies may lead to ocular surface desiccation, corneal ulceration and/or perforation, higher rates of infectious disease, and the risk of severe visual impairment and blindness. Clinical management remains largely supportive, palliative, and frequent, lifelong use of different lubricating agents. However, few advancements such as punctal plugs, non-steroidal anti-inflammatory drugs, and salivary gland autografts are of limited use. Cell-based therapies, tissue engineering, and regenerative medicine, have recently evolved as long-term cures for many diseases, including ophthalmic diseases. The present article focuses on the different regenerative medicine and reconstruction/bioengineered lacrimal gland formati...

Pluripotency of stem cells is governed by various factors, and Octamer-binding transcription fact... more Pluripotency of stem cells is governed by various factors, and Octamer-binding transcription factor 4 (Oct4) has been shown to be most essential regulator of Embryonic Stem Cells (ESCs) pluripotency. It is a key molecule for the reprogramming process and vastly used for IPSCs generation in research laboratories. Oct4 interacts directly with another important molecule Sox2 and elicitvarious downstream signals during the reprogramming. Sox2 is sex determining region-Y protein and involved in reprogramming through interaction with Oct4 and other pluripotency factors. Both of these transcription factors are known to bind enhancer element of specific genes regulating pluripotency such as fibroblast growth factor 4 (Fgf4) gene. Fgf4 has been proposed to promote self-renewation in human ESCs and support proliferation of mouse inner cell mass. The molecular mechanism for Oct4 interactions with Sox2 and their target gene(s) remain cryptic. The present study focuses on these aspects, and a co...

Frontiers in Bioengineering and Biotechnology, 2016

Thrombopoietin receptor (TPOR) is a cytokine receptor protein present on the cell surface. The ac... more Thrombopoietin receptor (TPOR) is a cytokine receptor protein present on the cell surface. The activation of TPOR by thrombopoietin (TPO) (a glycoprotein hormone) triggers an intracellular cascade of megakaryocytopoiesis for the formation of platelets. Recent studies on ex vivo megakaryocytopoiesis have evolved the possibilities of therapeutics uses. These findings have paved the way for the development of various TPO alternatives (recombinant TPO, peptide, and non-peptide TPO mimetics), which are useful in regenerative medicine. However, these alternatives possess various limitations such as induction of autoimmune effects, high production cost, low specificity, and hence activity. In the present study, a novel peptidic TPO mimetic was designed through computational studies by studying the binding sites of TPO and TMP to TPOR and analogs of known mimetics. Screening of combinatorial library was done through molecular docking using ClusPro. These studies indicated mimetic-9 as a significant molecule since it was found to have better binding score of −938.8 kcal/mol with seven hydrogen bonds and a high number of hydrophobic interactions, than known mimetic TMP with docking score of −798.4 kcal/mol and TMP dimer with docking score of −811.9 kcal/mol for TPOR. Mimetic9-TPOR complex was further assessed by the molecular dynamics simulation, and their complex was found to be stable with an RMSD value of 0.091 Å. While studying the parameters, mimetic-9 was found to have overall good physiochemical properties with positive grand average hydropathy (GRAVY) score and high instability index score and was found to be localized in the extracellular region. The designed mimetic-9 might prove to be a useful lead molecule for mimicking the role of TPO for in vitro platelet production with higher efficiency.

Nature Precedings, 2010

In many hematopoietic malignancies such as lymphomas & leukemias, aberrant differentiation is the... more In many hematopoietic malignancies such as lymphomas & leukemias, aberrant differentiation is the major feature of malignant phenotype that often results from a single genetic alteration and provides a site-specific target for therapy. Therefore, targeting of protein-protein interactions that have been identified as mediators of transcriptional repression that blocks normal hematopoietic differentiation holds great promise for therapeutic applications. An example is GATA-1, a critical erythroid transcription factor that is capable of suppressing the myeloid phenotype by down-regulating PU.1 in a dose-dependent manner. PU.1 is the most crucial transcription factor known to be required for myeloid differentiation of hematopoietic stem cells or progenitor cells. Its reduced expression correlates with a bad prognosis and immature phenotype in acute myeloid leukemia (AML). GATA-1 downregulates PU.1 by interacting though its C-terminal zinc finger region with the β3/β4 region of PU.1 and ...

Frontiers in Cell and Developmental Biology, 2014

Blood transfusions are routinely done in every medical regimen and a worldwide established collec... more Blood transfusions are routinely done in every medical regimen and a worldwide established collection, processing/storage centers provide their services for the same. There have been extreme global demands for both raising the current collections and supply of safe/adequate blood due to increasingly demanding population. With, various risks remain associated with the donor derived blood, and a number of post collection blood screening and processing methods put extreme constraints on supply system especially in the underdeveloped countries. A logistic approach to manufacture erythrocytes ex-vivo by using modern tissue culture techniques have surfaced in the past few years. There are several reports showing the possibilities of RBCs (and even platelets/neutrophils) expansion under tightly regulated conditions. In fact, ex vivo synthesis of the few units of clinical grade RBCs from a single dose of starting material such as umbilical cord blood (CB) has been well established. Similarly, many different sources are also being explored for the same purpose, such as embryonic stem cells, induced pluripotent stem cells. However, the major concerns remain elusive before the manufacture and clinical use of different blood components may be used to successfully replace the present system of donor derived blood transfusion. The most important factor shall include the large scale of RBCs production from each donated unit within a limited time period and cost of their production, both of these issues need to be handled carefully since many of the recipients among developing countries are unable to pay even for the freely available donor derived blood. Anyways, keeping these issues in mind, present article shall be focused on the possibilities of blood production and their use in the near future.

Eigenfrequencies of small adiabatic oscillations of stars obeying the generalized law of differential rotation

Bulletin of The Astronomical Society of India - BULL ASTRON SOC INDIA, 1995

Journal of Cellular and Molecular Medicine, 2009

Mesenchymal stem cells (MSCs), adherent fibroblastoid cells, present in bone marrow and many othe... more Mesenchymal stem cells (MSCs), adherent fibroblastoid cells, present in bone marrow and many other tissues can be easily isolated and expanded in vitro. They are capable of differentiating into different cell types such as osteoblasts, chondrocytes, adipocytes, cardiomyocytes, hepatocytes, endothelial cells and neuronal cells. Such immense plasticity coupled with their ability to modulate the activity of immune cells makes them attractive for stem cell-based therapy aimed at treating previously incurable disorders. Preclinical studies have reported successful use of MSCs for delivering therapeutic proteins and repairing defects in a variety of disease models. These studies highlighted the in vivo potential of MSCs and their ability to home to injury sites and modify the microenvironment by secreting paracrine factors to augment tissue repair. Their therapeutic applicability has been widened by genetic modification to enhance differentiation and tissue targeting, and use in tissue engineering. Clinical trials for diseases such as osteogenesis imperfecta, graft-versus-host disease and myocardial infarction have shown some promise, demonstrating the safe use of both allogeneic and autologous cells. However, lack of knowledge of MSC behaviour and responses in vitro and in vivo force the need for basic and animal studies before heading to the clinic. Contrasting reports on immunomodulatory functions and tumorigenicity along with issues such as mode of cell delivery, lack of specific marker, low survival and engraftment require urgent attention to harness the potential of MSC-based therapy in the near future.

Journal of stem cells, 2015

Induced Pluripotent Stem Cells (iPSCs) are self renewable and can differentiate to different type... more Induced Pluripotent Stem Cells (iPSCs) are self renewable and can differentiate to different types of adult cells, which has shown great promises in the field of regenerative medicine. iPSCs are reprogrammed from human somatic cells through ectopic expression of various transcription factors viz. Oct4, Sox2, Klf4, and c-Myc (OSKM). This novel technology enables derivation of patient specific cells, which possess a potential cure for many diseases. During the last decade, significant progresses have been achieved in enhancing the reprogramming efficiency, safety of iPSCs derivation, development of different delivery techniques by various research groups. Nevertheless, it is important to resolve and define the mechanism underlying the pluripotent stem cells. Major bottleneck which arises during iPSCs generation is the availability of source material (cells/tissues), difficulty to deliver transcription factors with no aberrant genetic modifications and limited reprogramming efficiency....

Frontiers in molecular biosciences, 2017

Cancer stem cells (CSCs) are believed to exhibit distinctive self-renewal, proliferation, and dif... more Cancer stem cells (CSCs) are believed to exhibit distinctive self-renewal, proliferation, and differentiation capabilities, and thus play a significant role in various aspects of cancer. CSCs have significant impacts on the progression of tumors, drug resistance, recurrence and metastasis in different types of malignancies. Due to their primary role, most researchers have focused on developing anti-CSC therapeutic strategies, and tremendous efforts have been put to explore methods for selective eradication of these therapeutically resistant CSCs. In recent years, many reports have shown the use of CSCs-specific approaches such as ATP-binding cassette (ABC) transporters, blockade of self-renewal and survival of CSCs, CSCs surface markers targeted drugs delivery and eradication of the tumor microenvironment. Also, various therapeutic agents such as small molecule drugs, nucleic acids, and antibodies are said to destroy CSCs selectively. Targeted drug delivery holds the key to the succ...

Artificial cells, nanomedicine, and biotechnology, Jan 7, 2017

Autoimmunity arises when highly active immune responses are developed against the tissues or subs... more Autoimmunity arises when highly active immune responses are developed against the tissues or substances of one's own body. It is one of the most prevalent disorders among the old-age population with prospects increasing with age. The major cause of autoimmunity and associated diseases is the dysregulation of host immune surveillance. Impaired repairment of immune system and apoptosis regulation can be seen as major landmarks in autoimmune disorders such as the mutation of p53 gene which results in rheumatoid arthritis, bowel disease which consequently lead to tissue destruction, inflammation and dysfunctioning of body organs. Cytokines mediated apoptosis and proliferation of cells plays a regulatory role in cell cycle and further in cancer development. Anti-TNF therapy, Treg therapy and stem cell therapy have been used for autoimmune diseases, however, with the increase in the use of immunomodulatory therapies and their development for autoimmune diseases and cancer, the underst...

Stage-Specific Regulation of Erythropoiesis and Its Implications in Ex-Vivo RBCs Generation

Journal of stem cells, 2016

Ex vivo erythropoiesis methods are being developed for more than a decade now, and all the distin... more Ex vivo erythropoiesis methods are being developed for more than a decade now, and all the distinct types of stem cells (such as CD34(+) HSCs, ESCs, IPSCs, and extensively proliferating erythropoietic progenitor cells) are defined to bear the potential for large scale RBC production shortly. The various regulating factors at different levels of RBCs production are being explored. Since most of the ex-vivo erythropoiesis protocols mimic the dogma followed by hematopoietic stem cells in vivo to give rise to mature RBCs which essentially deals with the intermediate stages of erythropoiesis such as burst forming unit-erythroid (BFU-E) and committed erythroid colony forming unit-erythroid (CFU-E). In vivo generation of erythroid progenitors (BFU-E/CFU-E) is essentially controlled by several factors including glucocorticoids, inflammation, and stress. Furthermore, regular production of functionally mature /transfusable units of RBCs is possible only through the coordinated regulation of t...

Frontiers in cell and developmental biology, 2016

Stem cells are defined by their capabilities to self-renew and give rise to various types of diff... more Stem cells are defined by their capabilities to self-renew and give rise to various types of differentiated cells depending on their potency. They are classified as pluripotent, multipotent, and unipotent as demonstrated through their potential to generate the variety of cell lineages. While pluripotent stem cells may give rise to all types of cells in an organism, Multipotent and Unipotent stem cells remain restricted to the particular tissue or lineages. The potency of these stem cells can be defined by using a number of functional assays along with the evaluation of various molecular markers. These molecular markers include diagnosis of transcriptional, epigenetic, and metabolic states of stem cells. Many reports are defining the particular set of different functional assays, and molecular marker used to demonstrate the developmental states and functional capacities of stem cells. The careful evaluation of all these methods could help in generating standard identifying procedures...

Hypothetical Model for the Suppression of Stress Induced Apoptosis in Hematopoietic Stem Cells

ABSTRACT Hematopoietic stem cells (HSC), which are responsible for maintaining continuous pool of... more ABSTRACT Hematopoietic stem cells (HSC), which are responsible for maintaining continuous pool of blood cells, are being used for bone marrow transplantation (BMT). However, the programmed cell death/ apoptosis poses a serious problem for their optimum proliferation and differentiation after radio- and/ or chemotherapy. The role of Bcl-2 (B Cell Lymphoma) protein, a Bcl-2 family member, is well established in suppressing apoptosis of HSC on irradiation and serum withdrawal. The anti-apoptotic activity of Bcl-2 is regulated by inter- and intra-family homo-/ heterodimerization. Here we are proposing that the potential of Bcl-2 and its survival enhancing mutants, such as D34A and S70E, may be harnessed (gene therapy) to suppress the radiation and growth factor withdrawal induced apoptosis provided the neoplastic outcomes of these genes are regulated. The suggested hypothetical model is likely to be helpful in treating blood borne disorders and radiation injury through BMT.

CD34 is a highly glycosylated surface-expressed sialomucin and, because it is present on hematopo... more CD34 is a highly glycosylated surface-expressed sialomucin and, because it is present on hematopoietic stem cells (HSCs), has demonstrated immense clinical utility in their enumeration in aphaeresis products, immunoaffinity purification for transplantation, and disease monitoring. The success of CD34 based reagents in identifying hematopoietic progenitors led to the assumption that CD34 is expressed on cells with regenerative potential and is sufficient for hematopoietic reconstitution in marrow-ablated recipients. Recently, researchers have identified the existence of CD34-neg HSCs, which have also been shown to successfully reconstitute hematopoiesis in both human and primate models. These reports stymied efforts to precisely define a critical role for CD34 in hematopoietic biology. reliminary reports indicated its role in the early hematopoiesis, differentiation, and proliferation of HSCs. However, evidences accumulated so far suggest that CD34 is predominantly an dhesion/anti-ad...

Human erythropoiesis is a complex multistep developmental process for production of erythrocytes ... more Human erythropoiesis is a complex multistep developmental process for production of erythrocytes (RBCs) from pluripotent hematopoietic stem cells (HSCs) in bone marrow microenvironment (HSCs niche). It is regulated by a plethora of growth factors and Erythropoietin (glycoprotein hormone) is most crucial and is produced mainly by peritubular capillary lining cells in kidney and in the liver. It circulates in the plasma acting on target cells present in the bone marrow for the regulation of proliferation, differentiation and maturation of red blood cells. Its amino acid sequence was first mapped out in 1983 has a stimulating effect on bone marrow erythroid precursors. It has been demonstrated through structural studies of human EPO that it is a single polypeptide of 30.4 kD with 166 amino acids residues which are folded into four α-helices and contain two disulphide bridges between cysteines (6-161 and 29 – 33). EPO is itself governed by various factors such as oxygen concentration an...

International Journal of Science and Research (IJSR)

Erythrpoitin receptor (EPOR) is a cytokine receptor protein, which on activation by binding to er... more Erythrpoitin receptor (EPOR) is a cytokine receptor protein, which on activation by binding to erythropoietin (EPO), triggers the intracellular cascade regulating differentiation and proliferation of erythropoietic progenitor cells into mature erythrocytes. EPO is a 34 KD glycoprotein hormone which specifically binds to EPOR and facilitates downstream signalling maintaining an adequate systemic availability of RBCs. For use of blood transfusion in various blood disorders such as anaemia, recombinant EPO and other mimetics have been reported, however, they have been found to be associated with certain risks and less potent to cure diseases. Targeting the binding site of EPOR to design small molecules and peptides which can retain the full agonist activity of the protein EPO may be a promising approach. Using computational approaches, large pool of diverse libraries can be analyzed to bind EPOR efficiently. In this study, the development of small EPO mimetic with therapeutic potential...

Nature Precedings, 2010

The CD34 antigen is a 115 KD surface glycoprotein present on primitive stem cells that has been w... more The CD34 antigen is a 115 KD surface glycoprotein present on primitive stem cells that has been widely employed as a marker for hematopoietic progenitors that are capable of reconstituting bone marrow (1). CD34-specific antibodies have recently become available and are an important tool in the study of CD34 function. The choice of cells that are CD34 + (positive) is important for transplantation; however, the subsequent identification of cells with no CD34 marker (negative) has contradicted the only sole potential of CD34+ (positive) cells in successful reconstitution of bone marrow (2). Although recent studies have documented the ability of CD34-(negative) cells to confer rapid engraftment with fewer risks of malignancy relapses, a large number of clinicians still prefer to use CD34+ (positive) cells for transplantation (3).

Advances in Regenerative Medicine, 2014

Erythropoiesis is a vital process governed through various factors. There is extreme unavailabili... more Erythropoiesis is a vital process governed through various factors. There is extreme unavailability of suitable donor due to rare phenotypic blood groups and other related complications like hemoglobinopathies, polytransfusion patients, and polyimmunization. Looking at the worldwide scarcity of blood, especially in low income countries and the battlefield, mimicking erythropoiesis usingex vivomethods can provide an efficient answer to various problems associated with present donor derived blood supply system. Fortunately, there are manyex vivoerythropoiesis methodologies being developed by various research groups using stem cells as the major source material for large scale blood production. Most of theseex vivoprotocols use a cocktail of similar growth factors under overlapping growth conditions. Erythropoietin (EPO) is a key regulator in mostex vivoprotocols along with other growth factors such as SCF, IL-3, IGF-1, and Flt-3. Now transfusable units of blood can be produced by usin...

Academia Medicine, Jan 30, 2024

Cancer cells differ from healthy tissues in their biological makeup. Recent research reported vas... more Cancer cells differ from healthy tissues in their biological makeup. Recent research reported vast genetic and epigenetic heterogeneity, differences in the gene-expression profiles, and signal transduction networks in a broad range of cancers. These discoveries led to the development and clinical approval of several drugs that are more efficient and can specifically target cancer-specific pathways to provide a long-lasting cure. Recent advancements in describing genetic alterations in human cancers are a tempting reason for scientists to develop more effective, personalized therapies as the next level of cancer treatment. However, the drug discovery process is tedious, and getting approval from various regulatory authorities may be more frustrating for a steady developmental pace. Among various prime regulators, the most critical challenge and priority in oncology research is to define unique molecular biomarkers, which would enhance the diagnosis. These molecular biomarkers should have the potential to beacon the prognostics, design, and monitoring of the newer therapeutics. Several key findings are being identified to discover and validate such molecular biomarkers for their diagnostic potential at the DNA, RNA, and protein levels. Furthermore, noninvasive imaging technologies and serum biomarkers are promising higher quality outputs in a limited time which could be a useful tool to monitor early responses to the treatment and may be able to design the remedial course. These advances would pave the way for personalized cancer therapeutics if translated beyond scientific discovery. This article highlights the various aspects of translational research and associated issues i.e. trial design, tissue collection, and regulatory requirements.

International Journal of Science and Research (IJSR), 2016

Differentiation and proliferation of megakaryocytic progenitor cells into mature platelets is tri... more Differentiation and proliferation of megakaryocytic progenitor cells into mature platelets is triggered and activated upon binding of Thrombopoietin Receptor (TPOR), a cytokine receptor protein, to thrombopoietin (TPO), a 95 KD glycoprotein hormone.TPO plays a very important role as it can easily direct Hematopoietic Progenitor Cells into the megakaryocytic lineage but even then very few mimetic have been reported, Agonists such as Romiplostim and Electrombopag are reported, recombinant TPO mimetic are also available but structural mimetic is only TMP, so the scope of further research is available. A promising approach for designing a mimetic can be targeting the binding site of the receptor such that the mimetic peptide has similar agonist activity as the ligand. Diverse libraries can be created using in-silico approaches and they are analyzed to bind receptor efficiently. In this study efforts are made for the development of TPO mimetic with therapeutic potential. TPO increases its number, prevent apoptosis, and thereby increases platelet production. Activation of TPO receptor leads to phosphorylation of the cytoplasmic domain as well as downstream activation of JAK2, STAT5, and other anti-apoptotic pathways. This increases the viability of stem cells and precursors of all lineages. The anti-apoptotic effect of TPO is probably important in patients with ITP: bone marrow megakaryocytes and megakaryocyte precursors are already increased but these cells are undergoing apoptosis mediated by anti-platelet IgG and T cells, thereby limiting platelet production. Administration of TPO decreases the apoptotic rate of the megakaryocyte precursors and thereby enhance the platelet production. Once produced, platelets are still affected by TPO. TPO's new Combinatorial library was designed by interaction sites of TPOR with TPO and previously reported TPO mimetic peptide (TMP), further screening of combinatorial library was done and an efficient mimetic was chosen based on scoring function commonly called Energy. Energy is calculated in terms of KJ/mol, based on the orientations generated by docking ligand with the receptor, the most efficient ligand has the most stable conformation with minimum energy value. In this study docking of TPO and TPOR has a minimum energy value of-518.20; TPOR and mimetic designed has a total score of-456.55which is better than the known mimetic TMP, which has an energy score of-170.17 with TPOR. Computational approaches confirmed that the resulting peptide mimetic was stable and similar in nature to TPO. Further Ex-vivo study of designed mimetic can confirm its role in regenerative medicine, increasing the shelf life of platelet to improve cellular viability of platelet by preventing programmed cell death, i.e. apoptosis, which can be achieved by adding TPO during storage since TPO levels increase when platelet count is low, to stimulate additional production. TPO is absorbed by transfused platelets, which may decrease available TPO level or in the disease condition.

Frontiers in Medicine

Significant research revealed the preocular tear film composition and regulations that remain vit... more Significant research revealed the preocular tear film composition and regulations that remain vital for maintaining Ocular surface functional integrity. Inflammation triggered by many factors is the hallmark of Ocular surface disorders or dry eyes syndrome (DES). The tear deficiencies may lead to ocular surface desiccation, corneal ulceration and/or perforation, higher rates of infectious disease, and the risk of severe visual impairment and blindness. Clinical management remains largely supportive, palliative, and frequent, lifelong use of different lubricating agents. However, few advancements such as punctal plugs, non-steroidal anti-inflammatory drugs, and salivary gland autografts are of limited use. Cell-based therapies, tissue engineering, and regenerative medicine, have recently evolved as long-term cures for many diseases, including ophthalmic diseases. The present article focuses on the different regenerative medicine and reconstruction/bioengineered lacrimal gland formati...

Pluripotency of stem cells is governed by various factors, and Octamer-binding transcription fact... more Pluripotency of stem cells is governed by various factors, and Octamer-binding transcription factor 4 (Oct4) has been shown to be most essential regulator of Embryonic Stem Cells (ESCs) pluripotency. It is a key molecule for the reprogramming process and vastly used for IPSCs generation in research laboratories. Oct4 interacts directly with another important molecule Sox2 and elicitvarious downstream signals during the reprogramming. Sox2 is sex determining region-Y protein and involved in reprogramming through interaction with Oct4 and other pluripotency factors. Both of these transcription factors are known to bind enhancer element of specific genes regulating pluripotency such as fibroblast growth factor 4 (Fgf4) gene. Fgf4 has been proposed to promote self-renewation in human ESCs and support proliferation of mouse inner cell mass. The molecular mechanism for Oct4 interactions with Sox2 and their target gene(s) remain cryptic. The present study focuses on these aspects, and a co...

Frontiers in Bioengineering and Biotechnology, 2016

Thrombopoietin receptor (TPOR) is a cytokine receptor protein present on the cell surface. The ac... more Thrombopoietin receptor (TPOR) is a cytokine receptor protein present on the cell surface. The activation of TPOR by thrombopoietin (TPO) (a glycoprotein hormone) triggers an intracellular cascade of megakaryocytopoiesis for the formation of platelets. Recent studies on ex vivo megakaryocytopoiesis have evolved the possibilities of therapeutics uses. These findings have paved the way for the development of various TPO alternatives (recombinant TPO, peptide, and non-peptide TPO mimetics), which are useful in regenerative medicine. However, these alternatives possess various limitations such as induction of autoimmune effects, high production cost, low specificity, and hence activity. In the present study, a novel peptidic TPO mimetic was designed through computational studies by studying the binding sites of TPO and TMP to TPOR and analogs of known mimetics. Screening of combinatorial library was done through molecular docking using ClusPro. These studies indicated mimetic-9 as a significant molecule since it was found to have better binding score of −938.8 kcal/mol with seven hydrogen bonds and a high number of hydrophobic interactions, than known mimetic TMP with docking score of −798.4 kcal/mol and TMP dimer with docking score of −811.9 kcal/mol for TPOR. Mimetic9-TPOR complex was further assessed by the molecular dynamics simulation, and their complex was found to be stable with an RMSD value of 0.091 Å. While studying the parameters, mimetic-9 was found to have overall good physiochemical properties with positive grand average hydropathy (GRAVY) score and high instability index score and was found to be localized in the extracellular region. The designed mimetic-9 might prove to be a useful lead molecule for mimicking the role of TPO for in vitro platelet production with higher efficiency.

Nature Precedings, 2010

In many hematopoietic malignancies such as lymphomas & leukemias, aberrant differentiation is the... more In many hematopoietic malignancies such as lymphomas & leukemias, aberrant differentiation is the major feature of malignant phenotype that often results from a single genetic alteration and provides a site-specific target for therapy. Therefore, targeting of protein-protein interactions that have been identified as mediators of transcriptional repression that blocks normal hematopoietic differentiation holds great promise for therapeutic applications. An example is GATA-1, a critical erythroid transcription factor that is capable of suppressing the myeloid phenotype by down-regulating PU.1 in a dose-dependent manner. PU.1 is the most crucial transcription factor known to be required for myeloid differentiation of hematopoietic stem cells or progenitor cells. Its reduced expression correlates with a bad prognosis and immature phenotype in acute myeloid leukemia (AML). GATA-1 downregulates PU.1 by interacting though its C-terminal zinc finger region with the β3/β4 region of PU.1 and ...

Frontiers in Cell and Developmental Biology, 2014

Blood transfusions are routinely done in every medical regimen and a worldwide established collec... more Blood transfusions are routinely done in every medical regimen and a worldwide established collection, processing/storage centers provide their services for the same. There have been extreme global demands for both raising the current collections and supply of safe/adequate blood due to increasingly demanding population. With, various risks remain associated with the donor derived blood, and a number of post collection blood screening and processing methods put extreme constraints on supply system especially in the underdeveloped countries. A logistic approach to manufacture erythrocytes ex-vivo by using modern tissue culture techniques have surfaced in the past few years. There are several reports showing the possibilities of RBCs (and even platelets/neutrophils) expansion under tightly regulated conditions. In fact, ex vivo synthesis of the few units of clinical grade RBCs from a single dose of starting material such as umbilical cord blood (CB) has been well established. Similarly, many different sources are also being explored for the same purpose, such as embryonic stem cells, induced pluripotent stem cells. However, the major concerns remain elusive before the manufacture and clinical use of different blood components may be used to successfully replace the present system of donor derived blood transfusion. The most important factor shall include the large scale of RBCs production from each donated unit within a limited time period and cost of their production, both of these issues need to be handled carefully since many of the recipients among developing countries are unable to pay even for the freely available donor derived blood. Anyways, keeping these issues in mind, present article shall be focused on the possibilities of blood production and their use in the near future.

Eigenfrequencies of small adiabatic oscillations of stars obeying the generalized law of differential rotation

Bulletin of The Astronomical Society of India - BULL ASTRON SOC INDIA, 1995

Journal of Cellular and Molecular Medicine, 2009

Mesenchymal stem cells (MSCs), adherent fibroblastoid cells, present in bone marrow and many othe... more Mesenchymal stem cells (MSCs), adherent fibroblastoid cells, present in bone marrow and many other tissues can be easily isolated and expanded in vitro. They are capable of differentiating into different cell types such as osteoblasts, chondrocytes, adipocytes, cardiomyocytes, hepatocytes, endothelial cells and neuronal cells. Such immense plasticity coupled with their ability to modulate the activity of immune cells makes them attractive for stem cell-based therapy aimed at treating previously incurable disorders. Preclinical studies have reported successful use of MSCs for delivering therapeutic proteins and repairing defects in a variety of disease models. These studies highlighted the in vivo potential of MSCs and their ability to home to injury sites and modify the microenvironment by secreting paracrine factors to augment tissue repair. Their therapeutic applicability has been widened by genetic modification to enhance differentiation and tissue targeting, and use in tissue engineering. Clinical trials for diseases such as osteogenesis imperfecta, graft-versus-host disease and myocardial infarction have shown some promise, demonstrating the safe use of both allogeneic and autologous cells. However, lack of knowledge of MSC behaviour and responses in vitro and in vivo force the need for basic and animal studies before heading to the clinic. Contrasting reports on immunomodulatory functions and tumorigenicity along with issues such as mode of cell delivery, lack of specific marker, low survival and engraftment require urgent attention to harness the potential of MSC-based therapy in the near future.

Journal of stem cells, 2015

Induced Pluripotent Stem Cells (iPSCs) are self renewable and can differentiate to different type... more Induced Pluripotent Stem Cells (iPSCs) are self renewable and can differentiate to different types of adult cells, which has shown great promises in the field of regenerative medicine. iPSCs are reprogrammed from human somatic cells through ectopic expression of various transcription factors viz. Oct4, Sox2, Klf4, and c-Myc (OSKM). This novel technology enables derivation of patient specific cells, which possess a potential cure for many diseases. During the last decade, significant progresses have been achieved in enhancing the reprogramming efficiency, safety of iPSCs derivation, development of different delivery techniques by various research groups. Nevertheless, it is important to resolve and define the mechanism underlying the pluripotent stem cells. Major bottleneck which arises during iPSCs generation is the availability of source material (cells/tissues), difficulty to deliver transcription factors with no aberrant genetic modifications and limited reprogramming efficiency....

Frontiers in molecular biosciences, 2017

Cancer stem cells (CSCs) are believed to exhibit distinctive self-renewal, proliferation, and dif... more Cancer stem cells (CSCs) are believed to exhibit distinctive self-renewal, proliferation, and differentiation capabilities, and thus play a significant role in various aspects of cancer. CSCs have significant impacts on the progression of tumors, drug resistance, recurrence and metastasis in different types of malignancies. Due to their primary role, most researchers have focused on developing anti-CSC therapeutic strategies, and tremendous efforts have been put to explore methods for selective eradication of these therapeutically resistant CSCs. In recent years, many reports have shown the use of CSCs-specific approaches such as ATP-binding cassette (ABC) transporters, blockade of self-renewal and survival of CSCs, CSCs surface markers targeted drugs delivery and eradication of the tumor microenvironment. Also, various therapeutic agents such as small molecule drugs, nucleic acids, and antibodies are said to destroy CSCs selectively. Targeted drug delivery holds the key to the succ...

Artificial cells, nanomedicine, and biotechnology, Jan 7, 2017

Autoimmunity arises when highly active immune responses are developed against the tissues or subs... more Autoimmunity arises when highly active immune responses are developed against the tissues or substances of one's own body. It is one of the most prevalent disorders among the old-age population with prospects increasing with age. The major cause of autoimmunity and associated diseases is the dysregulation of host immune surveillance. Impaired repairment of immune system and apoptosis regulation can be seen as major landmarks in autoimmune disorders such as the mutation of p53 gene which results in rheumatoid arthritis, bowel disease which consequently lead to tissue destruction, inflammation and dysfunctioning of body organs. Cytokines mediated apoptosis and proliferation of cells plays a regulatory role in cell cycle and further in cancer development. Anti-TNF therapy, Treg therapy and stem cell therapy have been used for autoimmune diseases, however, with the increase in the use of immunomodulatory therapies and their development for autoimmune diseases and cancer, the underst...

Stage-Specific Regulation of Erythropoiesis and Its Implications in Ex-Vivo RBCs Generation

Journal of stem cells, 2016

Ex vivo erythropoiesis methods are being developed for more than a decade now, and all the distin... more Ex vivo erythropoiesis methods are being developed for more than a decade now, and all the distinct types of stem cells (such as CD34(+) HSCs, ESCs, IPSCs, and extensively proliferating erythropoietic progenitor cells) are defined to bear the potential for large scale RBC production shortly. The various regulating factors at different levels of RBCs production are being explored. Since most of the ex-vivo erythropoiesis protocols mimic the dogma followed by hematopoietic stem cells in vivo to give rise to mature RBCs which essentially deals with the intermediate stages of erythropoiesis such as burst forming unit-erythroid (BFU-E) and committed erythroid colony forming unit-erythroid (CFU-E). In vivo generation of erythroid progenitors (BFU-E/CFU-E) is essentially controlled by several factors including glucocorticoids, inflammation, and stress. Furthermore, regular production of functionally mature /transfusable units of RBCs is possible only through the coordinated regulation of t...

Frontiers in cell and developmental biology, 2016

Stem cells are defined by their capabilities to self-renew and give rise to various types of diff... more Stem cells are defined by their capabilities to self-renew and give rise to various types of differentiated cells depending on their potency. They are classified as pluripotent, multipotent, and unipotent as demonstrated through their potential to generate the variety of cell lineages. While pluripotent stem cells may give rise to all types of cells in an organism, Multipotent and Unipotent stem cells remain restricted to the particular tissue or lineages. The potency of these stem cells can be defined by using a number of functional assays along with the evaluation of various molecular markers. These molecular markers include diagnosis of transcriptional, epigenetic, and metabolic states of stem cells. Many reports are defining the particular set of different functional assays, and molecular marker used to demonstrate the developmental states and functional capacities of stem cells. The careful evaluation of all these methods could help in generating standard identifying procedures...

Hypothetical Model for the Suppression of Stress Induced Apoptosis in Hematopoietic Stem Cells

ABSTRACT Hematopoietic stem cells (HSC), which are responsible for maintaining continuous pool of... more ABSTRACT Hematopoietic stem cells (HSC), which are responsible for maintaining continuous pool of blood cells, are being used for bone marrow transplantation (BMT). However, the programmed cell death/ apoptosis poses a serious problem for their optimum proliferation and differentiation after radio- and/ or chemotherapy. The role of Bcl-2 (B Cell Lymphoma) protein, a Bcl-2 family member, is well established in suppressing apoptosis of HSC on irradiation and serum withdrawal. The anti-apoptotic activity of Bcl-2 is regulated by inter- and intra-family homo-/ heterodimerization. Here we are proposing that the potential of Bcl-2 and its survival enhancing mutants, such as D34A and S70E, may be harnessed (gene therapy) to suppress the radiation and growth factor withdrawal induced apoptosis provided the neoplastic outcomes of these genes are regulated. The suggested hypothetical model is likely to be helpful in treating blood borne disorders and radiation injury through BMT.

CD34 is a highly glycosylated surface-expressed sialomucin and, because it is present on hematopo... more CD34 is a highly glycosylated surface-expressed sialomucin and, because it is present on hematopoietic stem cells (HSCs), has demonstrated immense clinical utility in their enumeration in aphaeresis products, immunoaffinity purification for transplantation, and disease monitoring. The success of CD34 based reagents in identifying hematopoietic progenitors led to the assumption that CD34 is expressed on cells with regenerative potential and is sufficient for hematopoietic reconstitution in marrow-ablated recipients. Recently, researchers have identified the existence of CD34-neg HSCs, which have also been shown to successfully reconstitute hematopoiesis in both human and primate models. These reports stymied efforts to precisely define a critical role for CD34 in hematopoietic biology. reliminary reports indicated its role in the early hematopoiesis, differentiation, and proliferation of HSCs. However, evidences accumulated so far suggest that CD34 is predominantly an dhesion/anti-ad...

Human erythropoiesis is a complex multistep developmental process for production of erythrocytes ... more Human erythropoiesis is a complex multistep developmental process for production of erythrocytes (RBCs) from pluripotent hematopoietic stem cells (HSCs) in bone marrow microenvironment (HSCs niche). It is regulated by a plethora of growth factors and Erythropoietin (glycoprotein hormone) is most crucial and is produced mainly by peritubular capillary lining cells in kidney and in the liver. It circulates in the plasma acting on target cells present in the bone marrow for the regulation of proliferation, differentiation and maturation of red blood cells. Its amino acid sequence was first mapped out in 1983 has a stimulating effect on bone marrow erythroid precursors. It has been demonstrated through structural studies of human EPO that it is a single polypeptide of 30.4 kD with 166 amino acids residues which are folded into four α-helices and contain two disulphide bridges between cysteines (6-161 and 29 – 33). EPO is itself governed by various factors such as oxygen concentration an...

International Journal of Science and Research (IJSR)

Erythrpoitin receptor (EPOR) is a cytokine receptor protein, which on activation by binding to er... more Erythrpoitin receptor (EPOR) is a cytokine receptor protein, which on activation by binding to erythropoietin (EPO), triggers the intracellular cascade regulating differentiation and proliferation of erythropoietic progenitor cells into mature erythrocytes. EPO is a 34 KD glycoprotein hormone which specifically binds to EPOR and facilitates downstream signalling maintaining an adequate systemic availability of RBCs. For use of blood transfusion in various blood disorders such as anaemia, recombinant EPO and other mimetics have been reported, however, they have been found to be associated with certain risks and less potent to cure diseases. Targeting the binding site of EPOR to design small molecules and peptides which can retain the full agonist activity of the protein EPO may be a promising approach. Using computational approaches, large pool of diverse libraries can be analyzed to bind EPOR efficiently. In this study, the development of small EPO mimetic with therapeutic potential...

Nature Precedings, 2010

The CD34 antigen is a 115 KD surface glycoprotein present on primitive stem cells that has been w... more The CD34 antigen is a 115 KD surface glycoprotein present on primitive stem cells that has been widely employed as a marker for hematopoietic progenitors that are capable of reconstituting bone marrow (1). CD34-specific antibodies have recently become available and are an important tool in the study of CD34 function. The choice of cells that are CD34 + (positive) is important for transplantation; however, the subsequent identification of cells with no CD34 marker (negative) has contradicted the only sole potential of CD34+ (positive) cells in successful reconstitution of bone marrow (2). Although recent studies have documented the ability of CD34-(negative) cells to confer rapid engraftment with fewer risks of malignancy relapses, a large number of clinicians still prefer to use CD34+ (positive) cells for transplantation (3).

Advances in Regenerative Medicine, 2014

Erythropoiesis is a vital process governed through various factors. There is extreme unavailabili... more Erythropoiesis is a vital process governed through various factors. There is extreme unavailability of suitable donor due to rare phenotypic blood groups and other related complications like hemoglobinopathies, polytransfusion patients, and polyimmunization. Looking at the worldwide scarcity of blood, especially in low income countries and the battlefield, mimicking erythropoiesis usingex vivomethods can provide an efficient answer to various problems associated with present donor derived blood supply system. Fortunately, there are manyex vivoerythropoiesis methodologies being developed by various research groups using stem cells as the major source material for large scale blood production. Most of theseex vivoprotocols use a cocktail of similar growth factors under overlapping growth conditions. Erythropoietin (EPO) is a key regulator in mostex vivoprotocols along with other growth factors such as SCF, IL-3, IGF-1, and Flt-3. Now transfusable units of blood can be produced by usin...