An Overview of Indian Biomedical Research on the Chikungunya Virus with Particular Reference to Its Vaccine, an Unmet Medical Need.

Chikungunya virus (CHIKV) is an infectious agent spread by mosquitos, that has engendered endemic or epidemic outbreaks of Chikungunya fever (CHIKF) in Africa, South-East Asia, America, and a few European countries. Like most tropical infections, CHIKV is frequently misdiagnosed, underreported, and underestimated; it primarily affects areas with limited resources, like developing nations. Due to its high transmission rate and lack of a preventive vaccine or effective treatments, this virus poses a serious threat to humanity. After a 32-year hiatus, CHIKV reemerged as the most significant epidemic ever reported, in India in 2006. Since then, CHIKV-related research was begun in India, and up to now, more than 800 peer-reviewed research papers have been published by Indian researchers and medical practitioners. This review gives an overview of the outbreak history and CHIKV-related research in India, to favor novel high-quality research works intending to promote effective treatment and preventive strategies, including vaccine development, against CHIKV infection.

Induction of G0/G1 phase cell cycle arrest and apoptosis by thymol through ROS generation and caspase-9/-3 activation in breast and colorectal cancer cell lines.

BACKGROUND: Cancer is a major malignancy and one of the leading causes of death; it calls for a proactive strategy for the cure. Herbs are reservoirs of novel chemical entities and their phytochemical exploration has contributed considerably to the discovery of new anticancer drugs. Thymol, a natural phenolic monoterpenoid, has been implicated with many medicinal properties, including anticancer ones. However, the anti-proliferative and apoptosis-inducing ability of thymol on MDA-MB-231 and HCT-8 cell lines has not been studied yet in detail, and hence this study was conceived. MATERIALS AND METHODS: We studied the cytotoxicity, morphological alterations of the cell, oxidative stress, cell cycle modulation, apoptosis and expression of apoptosis-related proteins that ensued due to thymol treatment in these cancer cells. RESULTS: Thymol inhibited the cell proliferation, altered the morphology of the cells, increased the intracellular ROS level, arrested the cells in G0/G1 phase, induced apoptosis, upregulated pro-apoptotic protein p53 expression, downregulated anti-apoptotic protein Bcl-xL expression, and activated caspase-9 and -3. CONCLUSION: These findings elucidate that thymol induces apoptosis through the intrinsic pathway, in MDA-MB-231 breast and HCT-8 colorectal cancer cells through ROS generation and G0/G1 phase cell cycle arrest. This reiterates the broad-spectrum anti-tumor potential of thymol and provides an insight to study further to be developed into an anticancer drug.

Quinacrine enhances the efficacy of cisplatin by increasing apoptosis and modulating cancer survival proteins in a colorectal cancer cell line.

BACKGROUND: Cisplatin and platinum-based compounds have been used successfully to treat various cancers. However, their use is often restricted due to the acquired resistance by cancer cells. Over-expression of p53 and inhibition of NF-kB sensitize several cancer cells towards cisplatin-induced apoptosis. Quinacrine, a cytotoxic drug with predictable safety revealed to concurrently suppress NF-kB and activate p53, which may be an attractive adjuvant in cisplatin chemotherapy. Therefore, the objective of the present study was to establish the role of quinacrine as an adjuvant in lowering the dose of cisplatin during cancer therapy to circumvent its toxic effects. MATERIALS AND METHODS: The colon cancer (HCT-8) cells were cultured and cell survival assays were performed using standard procedures. Cell cycle arrest and the extent of apoptosis were determined using a muse cell analyzer. Cancer survival proteins were analyzed using western blotting techniques. RESULTS AND CONCLUSION: We demonstrated that concomitant use of quinacrine with cisplatin increased cell apoptosis, suppressed cell proliferation and inhibited colony formation in a colorectal cancer cell line. Moreover, cell cycle arrest in the G0/G1 and G2/M phases and upregulation of p53 expression were observed. There was also downregulation of NF-kB and Bcl-xL protein expressions, both of which are associated with enhanced cell apoptosis and an increase in the sensitivity of cancer cells to cisplatin, overcoming its chemoresistance. Overall, the results of the present study and available literature clearly indicate that the use of quinacrine as an adjuvant with cisplatin may enhance its anti-cancer activity and reduce chemoresistance.

Pancreatic ß-Cell-Derived IP-10/CXCL10 Isletokine Mediates Early Loss of Graft Function in Islet Cell Transplantation.

Pancreatic islets produce and secrete cytokines and chemokines in response to inflammatory and metabolic stress. The physiological role of these "isletokines" in health and disease is largely unknown. We observed that islets release multiple inflammatory mediators in patients undergoing islet transplants within hours of infusion. The proinflammatory cytokine interferon-γ-induced protein 10 (IP-10/CXCL10) was among the highest released, and high levels correlated with poor islet transplant outcomes. Transgenic mouse studies confirmed that donor islet-specific expression of IP-10 contributed to islet inflammation and loss of ß-cell function in islet grafts. The effects of islet-derived IP-10 could be blocked by treatment of donor islets and recipient mice with anti-IP-10 neutralizing monoclonal antibody. In vitro studies showed induction of the IP-10 gene was mediated by calcineurin-dependent NFAT signaling in pancreatic ß-cells in response to oxidative or inflammatory stress. Sustained association of NFAT and p300 histone acetyltransferase with the IP-10 gene required p38 and c-Jun N-terminal kinase mitogen-activated protein kinase (MAPK) activity, which differentially regulated IP-10 expression and subsequent protein release. Overall, these findings elucidate an NFAT-MAPK signaling paradigm for induction of isletokine expression in ß-cells and reveal IP-10 as a primary therapeutic target to prevent ß-cell-induced inflammatory loss of graft function after islet cell transplantation.

Elemental analysis of scorpion venoms.

Scorpion venom is a rich source of biomolecules, which can perturb physiological activity of the host on envenomation and may also have a therapeutic potential. Scorpion venoms produced by the columnar cells of venom gland are complex mixture of mucopolysaccharides, neurotoxic peptides and other components. This study was aimed at cataloguing the elemental composition of venoms obtained from medically important scorpions found in the Arabian peninsula. The global elemental composition of the crude venom obtained from Androctonus bicolor, Androctonus crassicauda and Leiurus quinquestriatus scorpions were estimated using ICP-MS analyzer. The study catalogued several chemical elements present in the scorpion venom using ICP-MS total quant analysis and quantitation of nine elements exclusively using appropriate standards. Fifteen chemical elements including sodium, potassium and calcium were found abundantly in the scorpion venom at PPM concentrations. Thirty six chemical elements of different mass ranges were detected in the venom at PPB level. Quantitative analysis of the venoms revealed copper to be the most abundant element in Androctonus sp. venom but at lower level in Leiurus quinquestriatus venom; whereas zinc and manganese was found at higher levels in Leiurus sp. venom but at lower level in Androctonus sp. venom. These data and the concentrations of other different elements present in the various venoms are likely to increase our understanding of the mechanisms of venom activity and their pharmacological potentials.

Essential phospholipids prevent islet damage induced by proinflammatory cytokines and hypoxic conditions.

BACKGROUND: The pancreatic islet damage that occurs through an inflammatory response and hypoxia after infusion is a major hurdle in islet transplantation. Because essential phospholipids (EPL) have been shown to exhibit anti-inflammatory properties in liver disease, we analysed their protective effect on islets in inflammatory or hypoxic conditions. METHODS: We evaluated the viability of mouse and human islets cultured with cytokines or in hypoxic conditions for 48 h and measured cytokine expression in islets by quantitative polymerase chain reaction. We then employed an in vivo mouse assay, transplanting a marginal dose of human islets treated with or without EPL into the subcapsule of the kidney in diabetic nude mice and determining the cure rate. RESULTS: The viability of mouse and human islets damaged by cytokines was significantly improved by supplementation of EPL in the culture (p = 0.003 and <0.001 for mouse and human islets respectively). EPL significantly inhibited intracellular expression of IL-1ß and IL-6 in cytokine-damaged human islets (p < 0.001). The viability of human islets in hypoxic conditions was significantly better when treated with EPL (p < 0.001). In the in vivo mouse assay, the EPL-treated islet group had a higher cure rate than the untreated control, with marginal statistical significance (75 and 17% respectively, p = 0.07). CONCLUSIONS: EPL could be a potent agent to protect islets from inflammatory and hypoxic conditions after isolation procedures. Further studies to clarify the effect of EPL in islet transplantation are warranted.

NFAT targets signaling molecules to gene promoters in pancreatic ß-cells.

Nuclear factor of activated T cells (NFAT) is activated by calcineurin in response to calcium signals derived by metabolic and inflammatory stress to regulate genes in pancreatic islets. Here, we show that NFAT targets MAPKs, histone acetyltransferase p300, and histone deacetylases (HDACs) to gene promoters to differentially regulate insulin and TNF-α genes. NFAT and ERK associated with the insulin gene promoter in response to glucagon-like peptide 1, whereas NFAT formed complexes with p38 MAPK (p38) and Jun N-terminal kinase (JNK) upon promoters of the TNF-α gene in response to IL-1ß. Translocation of NFAT and MAPKs to gene promoters was calcineurin/NFAT dependent, and complex stability required MAPK activity. Knocking down NFATc2 expression, eliminating NFAT DNA binding sites, or interfering with NFAT nuclear import prevented association of MAPKs with gene promoters. Inhibiting p38 and JNK activity increased NFAT-ERK association with promoters, which repressed TNF-α and enhanced insulin gene expression. Moreover, inhibiting p38 and JNK induced a switch from NFAT-p38/JNK-histone acetyltransferase p300 to NFAT-ERK-HDAC3 complex formation upon the TNF-α promoter, which resulted in gene repression. Histone acetyltransferase/HDAC exchange was reversed on the insulin gene by p38/JNK inhibition in the presence of glucagon-like peptide 1, which enhanced gene expression. Overall, these data indicate that NFAT directs signaling enzymes to gene promoters in islets, which contribute to protein-DNA complex stability and promoter regulation. Furthermore, the data suggest that TNF-α can be repressed and insulin production can be enhanced by selectively targeting signaling components of NFAT-MAPK transcriptional/signaling complex formation in pancreatic ß-cells. These findings have therapeutic potential for suppressing islet inflammation while preserving islet function in diabetes and islet transplantation.

Pancreatic ductal perfusion at organ procurement enhances islet yield in human islet isolation.

OBJECTIVE: Pancreas preservation is a major factor influencing the results of islet cell transplantation. This study evaluated the effects of 2 different solutions for pancreatic ductal perfusion (PDP) at organ procurement. METHODS: Eighteen human pancreases were assigned to 3 groups: non-PDP (control), PDP with ET-Kyoto solution, and PDP with cold storage/purification stock solution. Pancreatic islets were isolated according to the modified Ricordi method. RESULTS: No significant differences in donor characteristics, including cold ischemia time, were observed between the 3 groups. All islet isolations in the PDP groups had more than 400,000 islet equivalence in total islet yield after purification, a significant increase when compared with the control (P = 0.04 and P < 0.01). The islet quality assessments, including an in vivo diabetic nude mice assay and the response of high-mobility group box protein 1 to cytokine stimulation, also showed no significant differences. The proportion of terminal deoxynucleotidyl transferase dUTP nick-end labeling-positive cells showing apoptosis in islets in the PDP groups was significantly lower than in the control group (P < 0.05). CONCLUSIONS: Both ET-Kyoto solution and cold storage/purification stock solution are suitable for PDP and consistently resulted in isolation success. Further studies with a larger number of pancreas donors should be done to compare the effects of the PDP solutions.

Inflammatory response in islet transplantation.

Islet cell transplantation is a promising beta cell replacement therapy for patients with brittle type 1 diabetes as well as refractory chronic pancreatitis. Despite the vast advancements made in this field, challenges still remain in achieving high frequency and long-term successful transplant outcomes. Here we review recent advances in understanding the role of inflammation in islet transplantation and development of strategies to prevent damage to islets from inflammation. The inflammatory response associated with islets has been recognized as the primary cause of early damage to islets and graft loss after transplantation. Details on cell signaling pathways in islets triggered by cytokines and harmful inflammatory events during pancreas procurement, pancreas preservation, islet isolation, and islet infusion are presented. Robust control of pre- and peritransplant islet inflammation could improve posttransplant islet survival and in turn enhance the benefits of islet cell transplantation for patients who are insulin dependent. We discuss several potent anti-inflammatory strategies that show promise for improving islet engraftment. Further understanding of molecular mechanisms involved in the inflammatory response will provide the basis for developing potent therapeutic strategies for enhancing the quality and success of islet transplantation.

Alleviation of instant blood-mediated inflammatory reaction in autologous conditions through treatment of human islets with NF-κB inhibitors.

BACKGROUND: The instant blood-mediated inflammatory response (IBMIR) has been shown as a major factor that causes damage to transplanted islets. Withaferin A (WA), an inhibitor of nuclear factor (NF) κB, was shown to suppress the inflammatory response in islets and improve syngeneic islet graft survival in mice. We investigated how treating islets with NF-κB inhibitors affected IBMIR using an in vitro human autologous blood islet model. METHODS: Human islets were pretreated with or without NF-κB inhibitors WA or CAY10512 before mixing autologous blood in a miniaturized in vitro tube model. Plasma samples were collected at multiple time points and used for the measurement of C-peptide, proinsulin, thrombin-antithrombin (TAT) complex, and a panel of proinflammatory cytokines. Infiltration of neutrophils into islets was analyzed using immunohistochemistry. RESULTS: Rapid release of C-peptide and proinsulin was observed 3 hr after mixing islets and blood in the control group, but not in the NF-κB inhibitor-treated groups, whereas TAT levels were elevated in all three groups with a peak at 6 hr. Significant elevation of proinflammatory cytokines was observed in the control group after 3 hr, but not in the treatment groups. Significant inhibition of neutrophil infiltration was also observed in the WA group compared with the control (P<0.001) and CAY10512 (P<0.001) groups. CONCLUSIONS: A miniaturized in vitro tube model can be useful in investigating IBMIR. The presence of NF-κB inhibitor could alleviate IBMIR, thus improving the survival of transplanted islets. Protection of islets in the peritransplant phase may improve long-term graft outcomes.