Diallyl disulfide inhibits TNFα induced CCL2 release through MAPK/ERK and NF-Kappa-B signaling.

TNFα receptors are constitutively overexpressed in tumor cells, correlating to sustain elevated NFκB and monocyte chemotactic protein-1 (MCP-1/CCL2) expression. The elevation of CCL2 evokes aggressive forms of malignant tumors marked by tumor associated macrophage (TAM) recruitment, cell proliferation, invasion and angiogenesis. Previously, we have shown that the organo-sulfur compound diallyl disulfide (DADS) found in garlic (Allium sativum) attenuates TNFα induced CCL2 production in MDA-MB-231 cells. In the current study, we explored the signaling pathways responsible for DADS suppressive effect on TNFα mediated CCL2 release using PCR Arrays, RT-PCR and western blots. The data in this study show that TNFα initiates a rise in NFκB mRNA, which is not reversed by DADS. However, TNFα induced heightened expression of IKKε and phosphorylated ERK. The expression of these proteins corresponds to increased CCL2 release that can be attenuated by DADS. CCL2 induction by TNFα was also lessened by inhibitors of p38 (SB202190) and MEK (U0126) but not JNK (SP 600125), all of which were suppressed by DADS. In conclusion, the obtained results indicate that DADS down regulates TNFα invoked CCL2 production primarily through reduction of IKKε and phosphorylated-ERK, thereby impairing MAPK/ERK, and NFκB pathway signaling. Future research will be required to evaluate the effects of DADS on the function and expression of TNFα surface receptors.

The role of inducible-nitric oxide in cocaine-induced kindling.

Experimentally naive male Sprague Dawley rats (weighing 85-110 g) were used to examine the role of inducible nitric oxide synthase (iNOS) in cocaine-induced kindling. Repeated administration of cocaine (45 mg/kg, i.p.) to Sprague Dawley male rats for 7 consecutive days produced a progressive increase in the convulsive responsiveness and death. Pretreatment with iNOS inhibitors, L-N6-(1-iminoethyl)lysine (NIL; 10 mg/kg, i.p.) and (-)-epigalloocatechin gallate (EGCG; 10 mg/kg, i.p.) 30 min before cocaine (45 mg/kg, i.p.) administration for 7 days attenuated the development of cocaine kindling and blocked cocaine-induced death. Results of NMDA receptor binding assay in the hippocampus showed a significant increase in the affinity without changes in the density in animals treated with cocaine, but there were no changes in these parameters in the cortex. Pretreatment with NIL or EGCG prior to cocaine administration abolished the cocaine-induced effect in the NMDA receptor affinity in the hippocampus. These results suggest that iNOS induction followed by an increase of NMDA receptor affinity in the hippocampus after repeated exposure to cocaine may participate in the process of the development of cocaine kindling.

Effect of dibutyryl cyclic AMP on the kinetics of myo-inositol transport in cultured astrocytes.

Dibutyryl cyclic AMP (dBcAMP) is known to induce maturation and differentiation in astrocytes. As myo-inositol is an important osmoregulator in astrocytes, we examined the effects of maturation and biochemical differentiation on the kinetic properties of myo-inositol transport. Treatment of astrocytes with dBcAMP significantly decreased the Vmax of myo-inositol uptake, but the effect on Km was not significant. The myo-inositol content of astrocytes was significantly decreased in cells treated for 5 days with dBcAMP as compared with untreated controls. Maximum suppression of myo-inositol uptake occurred 7 days after exposure of astrocytes to dBcAMP; this was gradually reversible when dBcAMP was removed from the medium. After exposure to hypertonic medium for 6 h, mRNA expression of the myo-inositol co-transporter was diminished by approximately 36% in astrocytes treated with dBcAMP as compared with untreated cells. It appears that myo-inositol transporters in astrocytes treated with dBcAMP are either decreased in number or inactivated during maturation and differentiation, suggesting that the stage of differentiation and biochemical maturation of astrocytes is an important factor in osmoregulation.

Induction of CD4+, human T lymphotropic virus type-1-specific cytotoxic T lymphocytes from patients with HAM/TSP. Recognition of an immunogenic region of the gp46 envelope glycoprotein of human T lymphotropic virus type-1.

Although the humoral response to human T lymphotropic virus type-1 (HTLV-I) has been well characterized in patients with HTLV-I-associated neurologic disease (HAM/TSP), little is known about a functional HTLV-I-specific human T cell response, such as CTL, in these patients. To define both the phenotype of the responding CTL and the fine specificity of this response, long term T cell lines were generated from two HAM/TSP patients who were from two different countries. Patient's peripheral blood lymphocytes were repeatedly stimulated in vitro with an HTLV-I expressing autologous T cell line. The resultant long term T cell culture was shown to be CD4+ and cytotoxic for targets expressing HTLV-I Ag. Using a panel of synthetic peptides that span hydrophilic regions of the HTLV-I gp46 envelope glycoprotein, the CTL lines generated from both patients were shown to recognize the same region of the HTLV-I envelope between amino acids 196-209 as defined by the synthetic peptide sp4a1. Interestingly, this sequence overlaps a region of HTLV-I envelope that had also been shown to elicit a strong B cell response in HAM/TSP patients (amino acids 190-203). One CTL line recognized this HTLV-I epitope in the context of HLA DQ5 whereas the other CTL line was restricted by HLA DRw16. The generation of two independent CTL lines from two HAM/TSP patients from different geographic areas that recognize the same region of the HTLV-I envelope glycoprotein highlights the immunogenic nature of this envelope region.

Spontaneous lymphocyte proliferation in HTLV-II infection.

We measured lymphocyte proliferation in the absence of antigenic stimulation in 45 HTLV-II infected, 9 HTLV-I infected, and 19 HTLV-I seronegative intravenous drug users (IVDU). Lymphocyte proliferation was higher in IVDUs infected with HTLV-II than in seronegative IVDUs but lower than among those infected with HTLV-I. Higher rates of proliferation were also associated with needle sharing, CD4+ and IL2R+ lymphocyte counts, and HTLV-I antibody titres.