Effects of stimulation of glutamate receptors in medial septum on some immune responses in rats

The glutaminase (CgGLS-1) mediates anti-bacterial immunity by prompting cytokine synthesis and hemocyte apoptosis in Pacific oyster Crassostrea gigas

Glutaminase, an amidohydrolase enzyme that hydrolyzes glutamine to glutamate, plays crucial roles in various immunomodulatory processes such as cell apoptosis, proliferation, migration, and secretion of cytokines. In the present study, a glutaminase homologue (designated as CgGLS-1) was identified from Pacific oyster Crassostrea gigas, whose open reading frame was of 1836 bp. CgGLS-1 exhibited high sequence identity with vertebrate kidney-type GLS, and closely clustered with their homologues from mollusc C. virginica. The enzyme activity of recombinant CgGLS-1 protein (rCgGLS-1) was estimated to be 1.705 U/mg. CgGLS-1 mRNA was constitutively expressed in all the tested tissues of oysters, with the highest expression level in hemocytes. CgGLS-1 mRNA expression in hemocytes was significantly up-regulated and peaked at 6 h (2.07-fold, p < 0.01) after lipopolysaccharide (LPS) stimulation. The CgGLS-1 protein was mainly distributed in the cytoplasm with a significant co-location with mitochondria in oyster hemocytes. The content of Glu in the oyster serum was significantly decreased after the inhibition of CgGLS-1 using specific inhibitor Bis-2- [5-(phenyl acetamido)-1,3,4-thiadiazol-2-yl] ethyl sulfide (BPTES), and the expression levels of CgmGluR6, CgAP-1, cytokines CgIL17-5 and CgTNF-1 were significantly decreased after BPTES and LPS stimulation. The transcripts of CgCaspase3 as well as the apoptosis index of hemocytes were also decreased. These results collectively suggest that CgGLS-1 is the enzyme to synthesize Glu in oyster, which can modulate anti-bacterial immunity by regulating the secretion of pro-inflammatory cytokines CgIL17-5 and CgTNF-1, as well as hemocyte apoptosis.

Etoricoxib inhibits peripheral inflammation and alters immune responses in intracerebroventricular colchicine injected rats

The present study was designed to investigate the effectiveness of etoricoxib induced inhibition of neuroinflammation by studying the peripheral inflammatory markers and select immune parameters in intracerebroventricular colchicine injected rats (ICIR). Results showed time dependent upregulation of the inflammatory markers in the serum along with alterations of peripheral immune parameters in ICIR and dose-dependent recovery was observed upon administration of etoricoxib to ICIR; most of these effects were greater with the longer duration of study. The present study indicates that colchicine induced neuroinflammation may cause systemic inflammation and alteration of immune responses which are mediated by increased cox- 2 activity.

Effects of stimulation of muscarinic acetylcholine receptors in medial septum on some immune responses in rats

OBJECTIVES

Though the immunomodulatory role of medial septum (MS) has been indicated, but the contribution of the muscarinic acetylcholine (mAch) receptors presented in the internal network of the neurons of MS in this regard is not known. The aim of the present study is to assess the contribution of mAch receptors of MS on some immunological parameters.

METHODS

Different immunological parameters i.e. phagocytic activity of peripheral leukocytes, adhesibility and cytotoxicity of splenic mononuclear cells (MNC), delayed type of hypersensitivity (DTH) responses, Total Count (TC) and Differential Count (DC) of WBC with serum corticosterone (CORT) concentration have been measured after stimulation and blocking of mAch receptors of MS in rats. Ach or atropine has been micro infused into MS of separate groups of rats for stimulating or blocking of the mAch receptors respectively.

RESULTS

In Ach or atropine microinfused rats, the TC of WBC remained unaltered in the present study. The percentage of neutrophil has increased and the percentage of lymphocyte has decreased in Ach microinfused rats, but these parameters remain unaltered in atropine microinfused rats. The observed immunological parameters have increased after microinfusion of 0.60μM and 0.12μM of Ach and serum CORT concentration has decreased in those animals. These immunological parameters have decreased and serum CORT has increased after microinfusion of atropine (2 and 4mM) in MS of rats.

CONCLUSION

It appears that the Ach receptors in MS can modulate the observed immunological parameters, and serum CORT plays an important role for these immune changes.

Medial Septal NMDA Glutamate Receptors are Involved in Modulation of Blood Natural Killer Cell Activity in Rats

The purpose of the present study was to determine the specific role of the medial septal (MS) NMDA glutamate receptors on peripheral blood natural killer cell cytotoxicity (NKCC) and their (large granular lymphocyte, LGL) number, as well as the plasma concentration of tumor necrosis factor α (TNF-α) and corticosterone in male Wistar rats exposed to elevated plus maze (EPM) stress or non-stress conditions. The NMDA groups were injected with NMDA glutamate receptor agonist (N-methyl-D-aspartate; 0.25 μg/rat), the D-AP7 group was injected with DL-2-amino-7-phosphoheptanoate (0.1 μg/rat), an antagonist of NMDA glutamate receptors, and the control Sal group with saline (0.5 μl/rat) via previously implanted cannulae into the MS. There was an increase in the NKCC, NK/LGL number and plasma TNF-α concentration after the NMDA injections, being much stronger within the rats under non-stress conditions rather than the rats exposed to EPM stress. These parameters were decreased in the D-AP7 rats, suggesting receptor/ion channel specificity. Moreover, a lower plasma corticosterone concentration within the NMDA rather than the Sal and D-AP7 groups was found. The obtained results suggest that activation of the NMDA glutamate receptors in the MS, accompanied by changes in the corticosterone and cytokine responses, may be involved in modulation of the blood natural anti-tumor response, under EPM stress and non-stress conditions.

Indian freshwater edible snail Bellamya bengalensis lipid extract prevents T cell mediated hypersensitivity and inhibits LPS induced macrophage activation

ETHNOPHARMACOLOGICAL RELEVANCE

Soup prepared from the foot of fresh water edible snail, Bellamya bengalensis, is traditionally consumed by the tribes of Jharkhand against rheumatism like bone and joint inflammation. As rheumatism has underlying involvement of cell mediated hypersensitivity, in vivo delayed-type hypersensitivity (DTH) model and in vitro LPS-induced macrophage signaling were studied to delineate the mechanism by which Bellamya bengalensis exerts its ethnomedicinal function. Since the whole meat is consumed, the lipid of Bellamya bengalensis (BBL) was hypothesized to be the active part.

METHODS AND MATERIALS

BBL isolated from the foot part of this species, was characterized and given by gavage daily (10mg BBL/kg; 20mg BBL/kg) to mice for 3 weeks prior to initiating development of DTH. Effects of DTH induced changes in paw diameter, serum nitric oxide (NO), serum tumor necrosis factor (TNF)-α level, CINC1 level, splenic CD4(+)/CD8(+) cell ratios, and level of splenic Treg cells were then compared with values in untreated control mice. In vitro effect of BBL on LPS-stimulated macrophage, the immune cell that is active in DTH, was assessed by NF-kB p65 nuclear translocation, reactive oxygen species (ROS), TNFα, and NO production.

RESULTS

BBL was characterized, and its supplementation in situ led to significant decrease in paw edema, tissue myeloperoxidase activity, NO level, serum TNFα level and CINC 1 level as well as decrease in splenic CD4(+)/CD8(+) ratios and increase in level of Treg cells. BBL was shown to inhibit ROS, NO, and TNFα production along with NF-kB p65 nuclear translocation in LPS stimulated macrophage.

CONCLUSION

Bellamya bengalensis, traditionally used against diseases with underlying etiology of cell mediated immunity as in rheumatism, which acts through inhibition of overexpressed cell mediated immunity. The factor exerting this activity probably is the oleic acid and cyclopropane fatty acid rich lipid, isolated after the ethnomedicinal clue, from the foot of this species.