Gautam Banerjee

The Role of Th17/IL-17 on Eosinophilic Inflammation

Eosinophilia develops in reactive environment such as allergy, parasitic infections and in hypereosinophilic syndrome [HES]. Activated eosinophils are accompanied by a wide variety of inflammatory response due to release of toxic inflammatory mediators, which may result in severe tissue/organ damage at the site of eosinophilic infiltrations, due to degranulation. The factor responsible for the detrimental effect of activated circulatory eosinophils is an area less explored. In the present study, we determined the serum cytokine milieu of eosinophilic and control subjects, and also investigated the change in the pattern of cytokine released under mitogen stimulation. Increased level of various pro-inflammatory cytokines such as IL-1β, IL-6, TNF-α, IL-5 and IL-17 was detected in serum and culture supernatants of endotoxin stimulated white blood cells [WBCs] of eosinophilic subjects compared to control population. It was observed that endotoxin exposure in WBCs of eosinophilic subjects, led to increased release of IL-17, produced by TH17 subset of T-cell, contributing towards eosinophilic exuberations, inxa0vitro. We observed non-specific lysis by eosinophils under such inflammatory milieu and synergistic eosinophilic activity in presence of IL-17 and IL-5 in combination. Taken together, our findings provide vital insight on TH17 lymphocyte mediated activation of eosinophils, via differential cytokine regulation, which play an important role in hypereosinophilic systemic inflammation.

l-Theanine promotes nitric oxide production in endothelial cells through eNOS phosphorylation

Consumption of tea (Camellia sinensis) improves vascular function and is linked to lowering the risk of cardiovascular disease. Endothelial nitric oxide is the key regulator of vascular functions in endothelium. In this study, we establish that l-theanine, a non-protein amino-acid found in tea, promotes nitric oxide (NO) production in endothelial cells. l-theanine potentiated NO production in endothelial cells was evaluated using Griess reaction, NO sensitive electrode and a NO specific fluorescent probe (4-amino-5-methylamino-2,7-difluororescein diacetate). l-Theanine induced NO production was partially attenuated in presence of l-NAME or l-NIO and completely abolished using eNOS siRNA. eNOS activation was Ca(2+) and Akt independent, as assessed by fluo-4AM and immunoblotting experiments, respectively and was associated with phosphorylation of eNOS Ser 1177. eNOS phosphorylation was inhibited in the presence of ERK1/2 inhibitor, PD-98059 and partially inhibited by PI3K inhibitor, LY-294002 and Wortmanin suggesting PI3K-ERK1/2 dependent pathway. Increased NO production was associated with vasodilation in ex ovo (chorioallantoic membrane) model. These results demonstrated that l-theanine administration in vitro activated ERK/eNOS resulting in enhanced NO production and thereby vasodilation in the artery. The results of our experiments are suggestive of l-theanine mediated vascular health benefits of tea.

Characterization of Two Homogalacturonan Pectins with Immunomodulatory Activity from Green Tea

Two natural homogalacturonan (HG) pectins (MW ca. 20 kDa) were isolated from green tea based on their immunomodulatory activity. The crude tea polysaccharides (TPS1 and TPS2) were obtained from green tea leaves by hot water extraction and followed by 40% and 70% ethanol precipitation, respectively. Two homogenous water soluble polysaccharides (TPS1-2a and TPS1-2b) were obtained from TPS1 after purification with gel permeation, which gave a higher phagocytic effect than TPS2. A combination of composition, methylation and configuration analyses, as well as NMR (nuclear magnetic resonance) spectroscopy revealed that TPS1-2a and TPS1-2b were homogalacturonan (HG) pectins consisting of a backbone of 1,4-linked α-d-galacturonic acid (GalA) residues with 28.4% and 26.1% of carboxyl groups as methyl ester, respectively. The immunological assay results demonstrated that TPS1-2, which consisted mainly of HG pectins, showed phagocytosis-enhancing activity in HL-60 cells.

Adiponectin and IL-6: Mediators of inflammation in progression of healthy to type 2 diabetes in Indian population.

Aim The objective of the study was to identify the association if any, of inflammatory markers (adiponectin and IL-6) with fasting glucose in normoglycemic (healthy), prediabetic (impaired fasting glucose), and hyperglycemic (diabetic) people in Indian population. Methods Total 162 volunteers were distributed into 3 groups (normoglycemic, individuals with impaired fasting glucose, and hyperglycemic) as per ADA criterion. The blood chemistry parameters were analyzed and serum adiponectin and IL-6 levels were measured by ELISA. Results Significant reduction was observed in serum adiponectin level in hyperglycemic and impaired fasting glucose population compared with normoglycemic population. Significant reduction in adiponectin was also observed in impaired fasting glucose group compared with hyperglycemic group. Similarly significant increase was also observed in IL-6 level in hyperglycemic and impaired fasting glucose groups compared with normoglycemic group. Conclusions From our data it can be summarized that there is a significant change in both adiponectin (reduction) and IL-6 (increase) levels in normoglycemic (healthy), prediabetic (impaired fasting glucose), and hyperglycemic (diabetic) population in Indian population. There is a significant but gradual change during the progression of healthy toward diabetic population via pre-diabetic condition.

In vivo enhancement of natural killer cell activity through tea fortified with Ayurvedic herbs

The effect of a tea fortified with five herbs selected from Indian traditional medicine (Ayurveda) for their putative immunoenhancing effect (Withania somnifera, Glycyrrhzia glabra, Zingiber officinale, Ocimum sanctum and Elettaria cardamomum) on innate immunity was investigated. Ex vivo natural killer (NK) cell activity was assessed after consumption of fortified tea compared with regular tea in two independent double‐blind intervention studies. Both studies were conducted in India with healthy volunteers (age ≥ 55 years) selected for a relatively low baseline NK cell activity and a history of recurrent coughs and colds. In a pilot study conducted with 32 volunteers, the consumption of Natural Care tea significantly improved the NK cell activity of the volunteers in comparison with a population consuming regular tea. These results were validated in an independent crossover study with 110 volunteers. Data from these two studies indicate that regular consumption of the tea fortified with Ayurvedic herbs enhanced NK cell activity, which is an important aspect of the (early) innate immune response to infections. Copyright