Shweta Saxena

Exogenous Sphingosine 1-Phosphate Protects Murine Splenocytes Against Hypoxia-Induced Injury

Abstract Sphingosine-1-phosphate (S1P), a biologically active pleiotropic lipid, is involved in several physiological processes especially in the area of vascular biology and immunology encompassing cell survival, angiogenesis, vascular tone, immune response etc. by interacting with specific cell surface receptors. Hypoxia, a condition common to innumerable pathologies, is known to lethally affect cell survival by throwing off balance global gene expression, redox homeostasis, bioenergetics etc. Several molecular events of cellular adaptations to hypoxia have been closely linked to stabilization of hypoxia inducible factor-1α (HIF-1α). Signalling functions of S1P in physiological events central to hypoxia-induced pathologies led us to investigate efficacy of exogenous S1P in preconditioning murine splenocytes to sustain during cellular stress associated with sub-optimal oxygen. The present study recapitulated the pro-survival benefits of exogenous S1P under normobaric hypoxia. Results indicate a direct effect of S1P supplementation on boosting cellular adaptive responses via HIF-1α stabilization and, activation of pro-survival mediators ERK and Akt. Overwhelming anti-oxidative and anti-inflammatory benefits of S1P preconditioning could also be captured in the present study, as indicated by improved redox homeostasis, reduced oxidative damage, balanced anti/pro-inflammatory cytokine profiles and temporal regulation of nitric oxide secretion and intra-cellular calcium release. Hypoxia induced cell death and the associated stress in cellular milieu in terms of oxidative damage and inflammation could be alleviated with exogenous S1P preconditioning.

Influence of light quality on growth, secondary metabolites production and antioxidant activity in callus culture of Rhodiola imbricata Edgew

Rhodiola imbricata is a rare medicinal herb well-known for its adaptogenic and antioxidant properties due to the presence of a diverse array of secondary metabolites, including phenylethanoids and phenylpropanoids. These secondary metabolites are generating considerable interest due to their potential applications in pharmaceutical and nutraceutical industries. The present study investigated the influence of light quality on growth, production of industrially important secondary metabolites and antioxidant activity in callus cultures of Rhodiola imbricata. Callus cultures of Rhodiola imbricata were established under different light conditions: 100% red, 100% blue, 100% green, RGB (40% red: 40% green: 20% blue) and 100% white (control). The results showed that the callus cultures grown under red light accumulated maximum amount of biomass (7.43 g/l) on day 21 of culture, as compared to other light conditions. Maximum specific growth rate (0.126 days-1) and doubling time (132.66 h) was observed in callus cultures grown under red light. Reverse phase-high performance liquid chromatographic (RP-HPLC) analysis revealed that the callus cultures exposed to blue light accumulated maximum amount of Salidroside (3.12 mg/g DW) on day 21 of culture, as compared to other light conditions. UV-Vis spectrophotometric analysis showed that the callus cultures exposed to blue light accumulated maximum amount of total phenolics (11.84 mg CHA/g DW) and total flavonoids (5.53 mg RE/g DW), as compared to other light conditions. Additionally, callus cultures grown under blue light displayed enhanced DPPH free radical scavenging activity (53.50%). Callus cultures grown under different light conditions showed no significant difference in ascorbic acid content (11.05-13.90 mg/g DW) and total antioxidant capacity (27.37-30.17 mg QE/g DW). The correlation analysis showed a positive correlation between total phenolic content and DPPH free radical scavenging activity in callus cultures (r = 0.85). Taken together, these results demonstrate the remarkable potential of light quality on biomass accumulation and production of industrially important secondary metabolites in callus cultures of Rhodiola imbricata. This study will open new avenues and perspectives towards abiotic elicitation strategies for sustainable growth and enhanced production of bioactive compounds in in-vitro cultures of Rhodiola imbricata.

Co-expression of S. Typhi GroEL and IL-22 gene augments immune responses against Salmonella infection

Recombinant DNA vaccines represent a novel method for generating in situ expression of vaccine antigens. Intramuscular injections of naked DNA are able to elicit potent humoral and cellular immune responses but still numerous factors limit the immunogenicity of DNA vaccines. Co‐expression of cytokines with antigen encoding genes in DNA vectors can improve the immune responses and modify Th1/Th2 balance. In this study, the immunomodulatory effect of Interleukin 22 (IL‐22) as an adjuvant was studied by DNA vaccination with S. Typhi Heat shock protein 60 (HSP60/GroEL) in mice. Further, DNA construct of IL‐22 gene fused with GroEL was developed and immunization studies were carried out in mice. DNA vaccination with GroEL alone stimulated humoral and cell‐mediated immune responses. Co‐immunization (IL‐22+GroEL) further resulted in increase in T‐cell proliferative responses, antibody titres (IgG, IgG1, IgG2a) and secretion of IFNγ (Th1), IL‐1β and Th2 (IL‐4, IL‐6) cytokines. Co‐expression (IL‐22‐GroEL DNA) also promoted antibody titres and cytokine levels were significantly higher as compared to co‐immunized group. A reduction in bacterial load in spleen, liver and intestine was seen in all the immunized groups as compared to control, with least organ burden in fusion DNA construct group (co‐expression). Improved protective efficacy (90%) against lethal challenge by Salmonella was observed with IL‐22‐GroEL co‐expressing DNA vector as compared with plasmid encoding GroEL only (50–60%) or co‐immunization group (75–80%). This study thus shows that co‐expression of IL‐22 and GroEL genes enhances the immune responses and protective efficacy, circumventing the need of any adjuvant.

Hippophae rhamnoides (Sea Buckthorn): A High-Altitude Medicinal and Adaptogenic Plant—Molecular Characterization and Bar-Coding

Medicinal plants have been used as herbal medicine by mankind since time immemorial in various traditional medicines, including Ayurveda. Sea buckthorn (Hippophae spp. L.) is a high-altitude-growing medicinal plant belonging to the family Elaeagnaceae. It is also known as gold mine of Himalayas. Due to genetic biodiversity of the plant, variations in phytochemicals responsible for biological activities do occur. To avoid these variations, proper identification of sea buckthorn plant is required to be done before using its product to carry out any scientific investigations or prepare any health product. Traditionally taxonomic classification of genus Hippophae is based on different morphological and biochemical features. These methods alone can be affected by many factors, leading to subtle and ambiguous results. Hippophae species are sometimes misidentified because of the similarities in vegetative morphology.

The MAPK-activator protein-1 signaling regulates changes in lung tissue of rat exposed to hypobaric hypoxia

This study reports the role of MAPKs (JNK, ERK, and p38), and activator protein‐1 (AP‐1) transcription factor in the hypobaric hypoxia induced change in lung tissue. Healthy male Sprague–Dawley rats were exposed to hypobaric hypoxia for 6, 12, 24, 48, 72, and 120 hr. Hypoxia resulted in significant increase in reactive oxygen species (ROS), vascular endothelial growth factor (VEGF) and decreased nitric oxide (NO), these act as signaling molecules for activation of MAPK and also contribute in development of vascular leakage (an indicator of pulmonary edema) as confirmed by histological studies. Our results confirmed JNK activation as an immediate early response (peaked at 6–48 hr), activation of ERKs (peaked at 24–72 hr) and p38 (peaked at 72–120 hr) as a secondary response to hypoxia. The MAPK pathway up regulated its downstream targets phospho c‐Jun (peaked at 6–120 hr), JunB (peaked at 24–120 hr) however, decreased c‐Fos, and JunD levels. DNA binding activity also confirmed activation of AP‐1 transcription factor in lung tissue under hypobaric hypoxia. Further, we analyzed the proliferative and inflammatory genes regulated by different subunits of AP‐1 to explore its role in vascular leakage. Increased expression of cyclin D1 (peaked at 12–72 hr) and p16 level (peaked at 48–120 hr) were correlated to the activation of c‐jun, c‐Fos and JunB. Administration of NFκB inhibitor caffeic acid phenethyl ester (CAPE) and SP600125 (JNK inhibitor) had no effect on increased levels of Interferon‐γ (IFN‐γ), Interleukin‐1 (IL‐1), and Tumor Necrosis Factor‐α (TNF‐α) thereby confirming the involvement of AP‐1 as well as NFκB in inflammation. Expression of c‐jun, c‐Fos were correlated with activation of proliferative genes and JunB, Fra‐1 with pro‐inflammatory cytokines. In conclusion immediate response to hypobaric hypoxia induced c‐Jun:c‐Fos subunits of AP‐1; responsible for proliferation that might cause inhomogeneous vasoconstriction leading to vascular leakage and inflammation at increased duration of hypobaric hypoxia exposure.

Phosphorus Compounds: Their Discovery in Biological World

Human kind shall be indebted to Dr. Subbarao Yellapragada for his discovery of Phosphorus estimation method. The first study on discovery of Phosphorus as an element revealed its biological link, dating back to 17th century. Hennig Brand, an alchemist, in a bid to study philosopher’s stone concentrated gallons of human urine and obtained an unknown substance,’ which he named ‘Phosphorus’ meaning light bearer [1]. In 18th century, the phosphorus was recognized as an important component of bones and the association of calcium and phosphorus was linked to rickets disease [2]. In the beginning of 20th century, Phosphorus was implicated in several human and microbial metabolic pathways [1–3].