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Gupta R.,Albert David Ltd | Gupta R.,University of Massachusetts Medical School | Palchaudhuri S.,Albert David Ltd | Chattopadhyay D.,University of Calcutta
Amino Acids | Year: 2013

Leukocytes are recruited at the site of infection or injury as a part of the innate immune system, and play a very critical role in fighting the invading microorganisms and/or healing wounds. Neutrophils are the most abundant leukocytes in healthy humans and are the principal cell types that arrive at the target site in the initial phase of this process. Previous studies from our laboratory have shown that the amino acid glutamate is a novel chemotaxis-inducing factor for human neutrophils. In this report, we provide evidences that clearly demonstrate that the glutamate-induced neutrophil cell migration activity is mediated by the class I metabotropic glutamate receptors. Our results further show that a specific integrin β2 (ITG β2) receptor, namely LFA1 (αLβ2) is activated upon glutamate treatment and is required for further downstream signaling events leading to increased migration of human neutrophil cells. Following glutamate stimulation, LFA1 is phosphorylated by the Src Kinase Lck at the Y735 residue, which triggers a downstream signaling cascade leading to activation of PI3K, Syk, Vav and finally the Rho family GTPase, Rac2. Interestingly, glutamate was previously found to be present in elevated levels in wound fluid. Furthermore, glutamate level was also found to go up following inflammation. Taken together, our study suggests a novel mode of neutrophil recruitment to the target site following an infection or injury. © 2012 Springer-Verlag.


De D.,Indian Institute of Chemical Technology | Datta Chakraborty P.,Albert David Ltd. | Mitra J.,Indian Institute of Chemical Technology | Sharma K.,Indian Institute of Chemical Technology | And 4 more authors.
PLoS ONE | Year: 2013

An aqueous extract of human placenta exhibits strong gelatinase/collagenase activity in zymography. 2-D gel electrophoresis of the extract with gelatin zymography in the second dimension displayed a single spot, identified as ubiquitin-like component upon MALDI/TOF MS/MS analysis. Immunoblot indicated presence of ubiquitin and absence of collagenase in the extract. Collagenase activity of the ubiquitin-like component was confirmed from the change in solubility of collagen in aqueous buffer, degradation of collagen by size-exclusion HPLC and atomic force microscopy. Quantification with DQ-gelatin showed that the extract contains 0.04 U/ml of collagenase activity that was inhibited up to 95% by ubiquitin antibody. Ubiquitin from bovine erythrocytes demonstrated mild collagenase activity. Bioinformatics studies suggest that placental ubiquitin and collagenase follow structurally divergent evolution. This thermostable intrinsic collagenase activity of placental extract might have wide physiological relevance in degrading and remodeling collagen as it is used as a drug for wound healing and pelvic inflammatory diseases. © 2013 De et al.


De D.,CSIR - Central Electrochemical Research Institute | Chakraborty P.D.,Albert David Ltd. | Bhattacharyya D.,CSIR - Central Electrochemical Research Institute
Journal of Cellular Physiology | Year: 2011

An aqueous extract of human placenta, used as wound healer, shows stabilization of trypsin against autodigestion as one of the peptides of the extract binds very strongly with the protease. Trypsin retains 40% of activity at constant level between 20 and 26 days in presence of the extract against complete inactivation in its absence. Inhibition of esterolytic activity and inability to react with p-nitrophenyl-p'-guanidinobenzoate, HCl, an active site directed reagent, by trypsin in presence of a peptide fraction of the extract indicated blocking of the catalytic site of the enzyme. Rayleigh scattering, size-exclusion HPLC, fluorescence resonance energy transfer, and surface plasmon resonance show that fibronectin type III-like peptide present in the extract interacts with trypsin. The peptide-trypsin complex is dissociated in presence of high concentration of substrates. Thus, regulation of trypsin activity by the placental extract is evident. © 2010 Wiley-Liss, Inc..


PubMed | Albert David Ltd
Type: Journal Article | Journal: Amino acids | Year: 2013

Leukocytes are recruited at the site of infection or injury as a part of the innate immune system, and play a very critical role in fighting the invading microorganisms and/or healing wounds. Neutrophils are the most abundant leukocytes in healthy humans and are the principal cell types that arrive at the target site in the initial phase of this process. Previous studies from our laboratory have shown that the amino acid glutamate is a novel chemotaxis-inducing factor for human neutrophils. In this report, we provide evidences that clearly demonstrate that the glutamate-induced neutrophil cell migration activity is mediated by the class I metabotropic glutamate receptors. Our results further show that a specific integrin 2 (ITG 2) receptor, namely LFA1 ((L)(2)) is activated upon glutamate treatment and is required for further downstream signaling events leading to increased migration of human neutrophil cells. Following glutamate stimulation, LFA1 is phosphorylated by the Src Kinase Lck at the Y735 residue, which triggers a downstream signaling cascade leading to activation of PI3K, Syk, Vav and finally the Rho family GTPase, Rac2. Interestingly, glutamate was previously found to be present in elevated levels in wound fluid. Furthermore, glutamate level was also found to go up following inflammation. Taken together, our study suggests a novel mode of neutrophil recruitment to the target site following an infection or injury.

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