Adjuvant activity of ethanol extract of Hippophae rhamnoides leaves with inactivated rabies virus antigen.

CONTEXT: Hippophae rhamnoides L. (Elaeagnaceae), commonly known as seabuckthorn (SBT), is known for its medicinal and nutritional properties. OBJECTIVE: Evaluation of in vivo adjuvant activity of SBT leaf extract (SBTE) with inactivated rabies virus antigen (Rb). MATERIALS AND METHODS: Swiss albino mice were immunized with aqueous-alcoholic SBTE (100 mg/kg body weight) or algel (aluminium hydroxide gel) with or without Rb (5% v/v). After priming, booster was administered on day 14. Rabies virus neutralizing antibody (RVNA) titers were estimated by rapid fluorescent focus inhibition test in sera samples collected on days 7, 14, 21, 28 and 35. Effect of adjuvant administration on cytotoxic T lymphocytes (CTLs), memory T cells, plasma and CD11c+ cells was studied by flow cytometry. In vitro hemolysis was assayed in human RBC. RESULTS: RVNA titers were significantly enhanced (p < 0.05) after booster administration in mice immunized with SBTE + Rb as compared to the controls. In combination, SBTE, algel and Rb, enhanced the RVNA titers. CTLs significantly increased (p < 0.05) in SBTE + Rb immunized mice. Memory T cells and plasma cells were 27.9 and 15.9%, respectively, in SBTE + Rb immunized mice as compared to that of 20.3 and 11.3%, respectively, in Rb immunized group. SBTE + Rb enhanced peritoneal CD11c+ cells (25.8%) as compared to 9.4% cells in Rb immunized mice, showed 3.2-fold increment in LPS induced IL-1ß. No RBC hemolysis was observed with SBTE. CONCLUSIONS: This study demonstrates the potential adjuvant activity of SBTE with Rb by increasing RVNA titers and CTL response.

A comparative immunological analysis of CoCl2 treated cells with in vitro hypoxic exposure.

The hypoxic preconditioning of mammalian cells has been shown to have beneficial effects against hypoxic injuries. However, very little information is available on the comparative analysis of immunological responses to hypoxic and hypoxia mimetic exposure. Therefore, in the present study, mouse peritoneal macrophages and splenocytes were subjected to hypoxia exposure (0.5 % O2) and hypoxia mimetic Cobalt chloride (CoCl2) treatment to evaluate their effect on immune response and delineate the underlying signaling mechanisms. The results obtained indicated that super oxide generation increased while TLR4 expression and cell surface markers like CD25, CD40 and CD69 were suppressed in both the treatments as compared to normoxia. Cobalt chloride treatment increased NF-κB expression, nitric oxide (NO) and iNOS expression, cytokines TNF-α and IL-6 as compared to hypoxia exposure. Our study showed that CoCl2 stabilizes HIF-1α to create hypoxia like conditions but it mainly influences the inflammatory response via NF-κB signaling pathway by skewing the production of proinflammatory molecules like TNF-α, IL-6 and NO.

Potential roles of protein disulphide isomerase in viral infections.

Protein disulphide isomerase (PDI) family members are predominantly endoplasmic reticulum (ER)-bound chaperonic proteins, which have also been shown to be present on the cell surface. Some of them have been found to be associated with lipid rafts, MHC class I, and cell-signaling molecules such as signal transducer and activator of transcription (STAT) proteins in certain viral infections. Since there is evidence suggesting that PDIs have a role in the virus entry to the cell, they obviously play an important role in virus-host interactions and viral pathogenesis. In this review, we discuss potential roles of PDIs in viral infections, in order to disclose new antiviral therapeutic targets.

nSARS-Cov-2, pulmonary edema and thrombosis: possible molecular insights using miRNA-gene circuits in regulatory networks.

BACKGROUND: Given the worldwide spread of the novel Severe Acute Respiratory Syndrome Coronavirus 2 (nSARS-CoV-2) infection pandemic situation, research to repurpose drugs, identify novel drug targets, vaccine candidates have created a new race to curb the disease. While the molecular signature of nSARS-CoV-2 is still under investigation, growing literature shows similarity among nSARS-CoV-2, pulmonary edema, and thromboembolic disorders due to common symptomatic features. A network medicine approach is used to to explore the molecular complexity of the disease and to uncover common molecular trajectories of edema and thrombosis with nSARS-CoV-2. RESULTS AND CONCLUSION: A comprehensive nSARS-CoV-2 responsive miRNA: Transcription Factor (TF): gene co-regulatory network was built using host-responsive miRNAs and it's associated tripartite, Feed-Forward Loops (FFLs) regulatory circuits were identified. These regulatory circuits regulate signaling pathways like virus endocytosis, viral replication, inflammatory response, pulmonary vascularization, cell cycle control, virus spike protein stabilization, antigen presentation, etc. A unique miRNA-gene regulatory circuit containing a consortium of four hub FFL motifs is proposed to regulate the virus-endocytosis and antigen-presentation signaling pathways. These regulatory circuits also suggest potential correlations/similarity in the molecular mechanisms during nSARS-CoV-2 infection, pulmonary diseases and thromboembolic disorders and thus could pave way for repurposing of drugs. Some important miRNAs and genes have also been proposed as potential candidate markers. A detailed molecular snapshot of TGF signaling as the common pathway, that could play an important role in controlling common pathophysiologies among diseases, is also put forth. SUPPLEMENTARY INFORMATION: Supplementary information accompanies this paper at 10.1186/s41544-020-00057-y.

Diversity and functional analysis of salivary microflora of Indian Antarctic expeditionaries.

Introduction: The human oral microbiota continues to change phenotype by many factors (environment, diet, genetics, stress, etc.), throughout life with a major impact on human physiology, psychology, metabolism and immune system. Amongst one such factor with unique and extreme environmental conditions is Antarctica. The sea voyage to Antarctica has many risks than at station for expedition members. In this study, we investigated the influence of Antarctic sea voyage and stay at the Indian Antarctic station Maitri, on the health of Indian expedition members by using a metagenomic approach to explore oral biodiversity. Methods: Saliva samples were collected from 12 expedition members, at 3 different time points viz. before the start of the ship voyage, after the completion of the voyage and at the end of the stay at Antarctica. Samples were analyzed for whole genome and 16S rRNA sequencing. Result: The oral microbial diversity of the expedition members was significantly changed, during the days of sailing and after the stay at Antarctica. The oral microbiota comprised mainly of the phyla Firmicutes (46%, 29% & 36%); Proteobacteria (40%, 48%, & 44%), Bacteroidetes (10%, 22%, &14%), Fusobacterium and Actinobacteria (5%-1%) and Unclassified (17%, 25% & 23%), at three time points, respectively. Further, the differential analysis of microbes across all the phyla revealed 89, 157 and 157 OTUs genera. The altered microbiota indicated changes in amino acid, lipid and carbohydrate metabolism. Conclusion: Study suggests that understanding the compositional and functional differences in the oral microbiota of Antarctic expedition members, can lay the foundation to relate these differences to their health status. It will further demonstrate the need for providing improved management during ship voyage and stay in Antarctica.

Aqueous extract of Rhodiola imbricata rhizome inhibits proliferation of an erythroleukemic cell line K-562 by inducing apoptosis and cell cycle arrest at G2/M phase.

Rhodiola imbricata is a medicinal plant having immunostimulating properties. The anti-proliferative effects of Rhodiola aqueous extract (RAE), were studied in human erythroleukemic cell line K-562 using MTT cell proliferation assay. The proliferation of K-562 was significantly decreased after 72h incubation with RAE at 100 and 200microg/ml. However, almost no suppressive effects could be detected in normal human peripheral blood lymphocytes or mouse macrophage cell line RAW-264.7. RAE was also found to induce intracellular reactive oxygen species (ROS) in K-562 cells at 200microg/ml when incubated overnight. The increased ROS generation may cause apoptosis, which was observed in AnnexinV-FITC and propidium iodide (PI) staining of cells treated with RAE for 72h in K-562 cells. Moreover, RAE arrested cell cycle progression in G2/M phase in early and late period of exposure. The anti-cancer activity of RAE was also confirmed by increased NK cell cytotoxicity. These observations suggest that aqueous extract of R. imbricata rhizome has very potent anti-cancer activities, which might be useful in leukemia cancer treatment.

A review of high throughput technology for the screening of natural products.

High throughput screening is commonly defined as automatic testing of potential drug candidates at a rate in excess of 10,000 compounds per week. The aim of high throughput drug discovery is to test large compound collections for potentially active compounds ('hits') in order to allow further development of compounds for pre-clinical testing ('leads'). High throughput technology has emerged over the last few years as an important tool for drug discovery and lead optimisation. In this approach, the molecular diversity and range of biological properties displayed by secondary metabolites constitutes a challenge to combinatorial strategies for natural products synthesis and derivatization. This article reviews the approach of High throughput technique for the screening of natural products for drug discovery.

Effect of Seabuckthorn (Hippophae rhamnoides) flavone on immune system: an in-vitro approach.

There are several reports, which suggest that the consumption of foods rich in flavonoids is associated with a lower incidence of certain degenerative diseases, including cardiovascular disease. Flavones, of Seabuckthorn (SBT) (Hippophae rhamnoides L.) fruit berry can modulate the production and level of several signaling molecules associated with immune function and inflammation in vitro, including several cytokines. We have evaluated the immunomodulatory activity of ethanolic solution of SBT flavone (FLV) in human peripheral blood mononuclear cells (PBMCs). The SBT flavone was found to stimulate production of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) in PBMCs. However, increased expressions of p-IkappaB, NF-kappaB, and p-p38 were found in flavone-treated human PBMCs with significantly suppressed expression of CD25 (IL-2R). There was no alteration found in the nitric oxide (NO) production in mouse macrophage cell line RAW 264.7. These observations suggest that stimulation of IL-6 and TNF-alpha secretion may contribute to the putative beneficial effects of dietary flavone against microbial infection.

Dengue virus non-structural 1 protein interacts with heterogeneous nuclear ribonucleoprotein H in human monocytic cells.

OBJECTIVE: To study protein-protein interaction between heterogeneous nuclear ribonucleoprotein H (hnRNP H) and Dengue virus (DENV) proteins. METHODS: DENV proteins were screened against the host hnRNP H protein, in order to identify the host-viral protein-protein interactions in DENV infected THP-1 cells by co-immunoprecipitation. The co-localization of the interacting proteins was further confirmed by immunofluorescence microscopy. RESULTS: The host protein hnRNP H was found to interact with DENV non-structural 1 protein and help the virus to multiply in the cell. CONCLUSIONS: The non-structural 1 glycoprotein is a key modulator of host immune response and is also involved in viral replication. Therefore, disruption of this key interaction between hnRNP H and DENV non-structural 1 could be an important therapeutic strategy for management of DENV infection.

Dot-enzyme linked immunosorbent assay for the detection of antibodies in bovine brucellosis.

A dot-enzyme linked immunosorbent assay (dot-ELISA) for the detection of antibodies in bovine brucellosis using soluble antigens extracted from Brucella abortus S-99 is described in which antigen was deposited on a nitrocellulose sheet (0.5 x 0.5 cm) bound to a plastic strip and the unsaturated sites blocked by a solution of spray-dried milk powder. Sera were tested at dilutions of 1:800 and 1:1600, using rabbit anti-bovine-immunoglobulin or protein-A coupled to peroxidase as conjugates and diamino-benzidine as substrate. A positive reaction was clearly indicated by a brown dot on the nitrocellulose sheet. Using antigen-coated, pre-blocked strips, the test could be completed within 45 minutes.

Immunomodulatory effect of laser on whole body exposure.

All biomedical laser applications are based on the interaction of laser light with biological system. During the past decade considerable evidence has accumulated demonstrating that non-thermal exposure to laser can elicit cellular changes in the immune system. In the present study, we have analyzed the effect of laser on immune response in rats. A group of rats were exposed to 0.225 mu j/cm2 for 90 min for 3 days in specially designed fiberglass chambers. The whole body exposure of rats of He-Ne laser modulated both the humoral and cellular responses to tetanus toxoid stimulation. Plain red light used as a control for red laser light showed an appreciable degree of response as compared to the control groups, but not to the extent of the response to laser. Non-responders turned responders after exposure to laser. There was no response in unimmunized groups when exposed to laser and red light alone. The early and heightened immune response and proliferation of lymphocytes after exposure to laser is suggestive of a complex interaction at the cellular immune response level.

Induction of stress proteins in response to hypoxia.

Hypoxia is a severe stress factor to which man and most other mammalian species are capable of adapting. However, the cellular mechanism which enable cells to adapt are still unknown. Effect of hypoxia was studied on the synthesis of hypoxia induced proteins in rat kidney and in vero cell line (monkey kidney). These were exposed to hypoxia at 240 mmHg pressure for 1 hr. The induction of stress protein was determined by probing with monoclonal antibodies against 65 kDa heat shock protein (hsp65). The induction of a 65 kDa protein was 3.6 fold higher to the total cellular protein, both in cell lines and kidney of rats. In vivo response was predominantly observed in renal cortical region particularly in glomeruli. The induction of stress proteins during hypoxia suggests their importance in the maintenance of cellular integrity under hypoxia.

Supercritical extract of Seabuckthorn Leaves (SCE200ET) inhibited endotoxemia by reducing inflammatory cytokines and nitric oxide synthase 2 expression.

Endotoxins from infectious organisms lead to sepsis, a systemic inflammatory response, and a major cause of death. Numerous studies have shown the potential role of plants and plant-derived compounds in the suppression of LPS induced endotoxemia in vivo. In the present study, we have identified a plant namely Seabuckthorn (Hippophae rhamnoides L.) as a potent agent for the treatment of endotoxemia. The objective of the study was to investigate the influence of Supercritical Extract of Seabuckthorn Leaves (SCE200ET) and its active component Isorhamnetin (IR) on the LPS induced endotoxemia in Balb/c mice by measuring the level of nitric oxide (NO), TNF-α and IL-6. Expression of COX-2 and iNOS was measured to understand the involvement of various pathways in the mechanism of action of SCE200ET and IR. The results indicated that SCE200ET and IR inhibited LPS induced NO production by peritoneal macrophages. Cytokines mediated effector functions were influenced by the reduction of IL-6 and TNF-α production and CD40 expression was also markedly diminished in the extract or IR treated groups. In addition, the anti-inflammatory properties were further characterized by decreased expression of COX-2 and iNOS proteins. Fractionation and phytochemical analysis of the extract by RP-HPLC led to identification of isorhamnetin, as bioactive component. Thus, SCE200ET extract and its active component Isorhamnetin could be potential therapeutic agents for the treatment of endotoxin induced sepsis.

A supercritical CO2 extract from seabuckthorn leaves inhibits pro-inflammatory mediators via inhibition of mitogen activated protein kinase p38 and transcription factor nuclear factor-κB.

In the present study, we have demonstrated the anti-inflammatory properties of supercritical CO2 extract of seabuckthorn leaves (SCE) on mouse alveolar macrophage cell line (MH-S), human peripheral blood mononuclear cells (hPBMCs) in-vitro and in-vivo. Treatment of MH-S cells with SCE (0.5-100 µg/ml) significantly inhibited lipopolysaccharide (LPS)-stimulated nitric oxide (NO) production. It also inhibited the release of LPS-induced pro-inflammatory cytokines IL-6 and TNF-α, which was further confirmed by suppression of LPS induced TNF-α in hPBMCs by ELISPOT assay. In addition, western blot analysis demonstrated that SCE decreased LPS-induced inducible nitric-oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein expression in MH-S cells. Furthermore, SCE treatment also reduced nuclear factor-κB (NF-κB) translocation in nucleus induced by LPS in MH-S cells. To elucidate the molecular mechanism for inhibition of pro-inflammatory mediators by SCE (100 µg/ml), we further studied the effect of SCE on LPS-induced p38 mitogen-activated protein kinase (MAPK). It was observed that the phosphorylation of p38 MAPK in LPS-stimulated MH-S cells was significantly inhibited by SCE, which was further proven by suppression of LPS induced CD40 expression. The in-vivo model of AIA mice also showed a significant reduction in the inflammation of paw edema. These data collectively suggest that SCE suppressed the LPS-induced production of NO, IL-6, and TNF-α and expression of CD40, iNOS and COX-2 proteins by inhibiting NF-κB activation and phosphorylation of p38 MAPK. Hence, the SCE has potent anti-inflammatory activity and might be useful in chronic inflammatory diseases.

Dengue virus infection activates cellular chaperone Hsp70 in THP-1 cells: downregulation of Hsp70 by siRNA revealed decreased viral replication.

The pathogenic mechanism of dengue virus infection is related to the host responses within target cells, and therefore we assessed intracellular changes in stress proteins following dengue virus infection. This study provides evidence that Hsp70 helps in viral multiplication by suppressing the type 1 interferon response. Dengue virus infection in human monocytic THP-1 cells led to overexpression of Hsp70, which also acts as a chaperone. The functional role of Hsp70 in dengue virus multiplication was identified by downregulating the Hsp70 gene with its specific siRNA duplexes, which led to a decrease in viral RNA copy numbers in cellular supernatants and intracellular viral load. It also resulted in an increased IFN-α level, which mediates its antiviral effect through double-stranded RNA-induced protein kinase-PKR. Collectively these results suggest that an increased level of Hsp70 expression in dengue-virus-infected THP-1 cells assists in viral replication by escaping the antiviral effect of type 1 interferon.

RNA interference mediated silencing of Hsp60 gene in human monocytic myeloma cell line U937 revealed decreased dengue virus multiplication.

Heat shock proteins (Hsps) or stress proteins are highly conserved molecules and expressed in all cell types under stressful conditions like heat, cold, hypoxia and infections. The objective of the present study was to determine the effect of dengue virus infection on relative expression of stress proteins and their role in the progression of the infection. As macrophages are the primary host for dengue, human promonocytic myeloblastoma U937 cells were infected with dengue virus type 2 New Guinea C strain for the evaluation of Hsps expression. A significant expression of Hsp60 was observed in virally infected U937 cells as compared to controls. In order to determine the correlation between Hsp60 expression and viral multiplication in infected cells, expression of Hsp60 was down regulated by RNA interference. Viral multiplication was determined by quantification of viral RNA copy number using Real Time PCR and plaque formation assay in cellular supernatants of Hsp60 silenced cells. Intracellular quantification of viral load was also determined by flow cytometry. It was observed that down regulation of Hsp60 in virally infected cells resulted into decrease in viral RNA copy number, plaque forming units and intracellular viral load. At the same time down regulation also resulted in increased IFN-alpha level. These observations suggest that, elevated levels of Hsp60 expression in virally infected cells may help in viral multiplication and could be possible therapeutic targets for the management of dengue virus infection.

Effect of Hippophae rhamnoides leaf extract against Dengue virus infection in human blood-derived macrophages.

Dengue virus occurs as four distinct serotypes, called Dengue 1, 2, 3, and 4. Symptomatic dengue virus infection ranges from a self limited febrile illness, dengue fever (DF), to a more severe disease, dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS). The anti-Dengue treatment is severely hampered as no specific therapeutic agents are available. Even present treatment strategies for Dengue are more supportive than curative. In the present study anti-dengue activity of Hippophae rhamnoides (Seabuckthorn, SBT) leaf extract was evaluated in Dengue virus type-2 infected blood-derived human macrophages as macrophages are the primary target of Dengue virus infection. Infected cells were treated with SBT leaf extract and compared with commercially available anti-viral drug, Ribavirin. The extract was able to maintain the cell viability of Dengue-infected cells at par with Ribavirin along with the decrease and increase in TNF-alpha and IFN-gamma respectively. Anti-dengue activity of SBT extract was further determined by the traditional plaque assay. These observations suggest that the SBT leaf extract has a significant anti-dengue activity and has the potential for the treatment of Dengue.

Aqueous extract of Rhodiola imbricata rhizome stimulates proinflammatory mediators via phosphorylated IkappaB and transcription factor nuclear factor-kappaB.

Modulation of immune response to alleviate diseases has long since been of interest. Plant extracts have been widely investigated for their possible immunomodulatory properties. We have evaluated the immunomodulatory activity of aqueous extract of Rhodiola rhizome in human peripheral blood mononuclear cells (PBMCs) and mouse macrophage cell line RAW 264.7. The Rhodiola extract was found to stimulate production of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) in human PBMCs as well as RAW 264.7 cell line. It also increased production of nitric oxide synergistically in combination with lipopolysaccharide (LPS) in RAW 264.7. Rhodiola at 250 microg/ml increased the p-IkappaB expression in human PBMCs. Aqueous extract of Rhodiola (250 microg/ml) also activated the nuclear translocation of NF-kappaB in human PBMCs, which is comparable to the positive stimulant LPS. Thus, our present study suggests that Rhodiola most likely activates proinflammatory mediators via phosphorylated inhibitory kB and transcription factor NF-kB. Our study demonstrates immunostimulatory potential of aqueous extract of Rhodiola rhizome, that can be used for upregulation of immune response in patients with inadequate functioning of the immune system.

Use of filter paper discs as substrate for collection and storage of blood samples for screening of anti-tetanus toxoid antibodies.

A sensitive and specific enzyme-linked immunosorbent assay (ELISA) for detection of antibodies to tetanus in dried blood samples spotted on filter paper discs has been developed. A good correlation was found between the two methods, filter paper disc assay and direct blood assay (r = 0.91). The specificity of the test was determined by a competitive inhibition assay using goat anti-tetanus-toxoid antibodies coupled to horseradish peroxidase. The interassay coefficient of variation is 10-12%. The antibodies were measurable until 4 months of storage of filter paper discs at room temperature (25 degrees C). This procedure is useful for mass screening of anti-tetanus antibodies using dried blood samples on filter paper discs.

Vasopressin-induced heat shock protein expression in renal tubular cells.

Heat shock proteins (HSPs), which have been shown to be induced in the kidney by a variety of stress conditions, including ischemia, inflammation, oxidative stress, and toxin exposure, are believed to protect the cells from injury. In the present study, we demonstrated that administration of vasopressin i.v. to Wistar rats leads to HSP70 induction in the kidney. The effect was specific to the kidney (i.e., absent in brain, heart, lung, muscle, etc.) and selective for the HSP70 gene family (HSP27, HSP60, and HSP90 were not induced). Western blot analysis demonstrated that HSP70 protein expression peaked between 6 and 12 hours after vasopressin administration. Immunohistochemical staining revealed that induction was localized to renal tubule lining cells, with no expression seen in glomerular or interstitial regions. The elevated protein levels were preceded by the induction of HSP70 mRNA within 30 minutes after vasopression injection. The induction of HSP70 mRNA was associated with the activation of heat shock transcription factor 1 (HSF1), suggesting that the response was regulated at the level of transcription. This HSP70 expression was completely blocked in the presence of both a general vasopressin receptor antagonist (V1 and V2 receptors) and an antidiuretic antagonist (V2), but not in the presence of a vasopressor antagonist (V1). These observations could be significant for understanding the possible involvement of HSP70 in physiological processes of the kidney, as well as pathophysiologic conditions associated with either elevated or deficient levels of vasopressin.