Endorphin peptides enhance mitogen-induced T cell proliferation which has been suppressed by prostaglandins

CCL5/RANTES gene deletion attenuates opioid-induced increases in glial CCL2/MCP-1 immunoreactivity and activation in HIV-1 Tat-exposed mice

To assess the role of CC-chemokine ligand 5 (CCL5)/RANTES in opiate drug abuse and human immunodeficiency virus type 1 (HIV-1) comorbidity, the effects of systemic morphine and intrastriatal HIV-1 Tat on macrophage/microglial and astroglial activation were assessed in wild-type and CCL5 knockout mice. Mice were injected intrastriatally with vehicle or Tat and assessed after 7 days. Morphine was administered to some Tat-injected mice via time-release implant (5 mg/day, s.c. for 5 days) starting at 2 days post injection. Glial activation was significantly reduced in CCL5(-/-) compared to wild-type mice at 7 days following combined Tat and morphine exposure. Moreover, the percentage of 3-nitrotyrosine immunopositive macrophages/microglia was markedly reduced in CCL5(-/-) mice injected with Tat +/- morphine compared to wild-type counterparts, suggesting that CCL5 contributes to nitrosative stress in HIV-1 encephalitis. In CCL5(-/-) mice, the reductions in Tat +/- morphine-induced gliosis coincided with significant declines in the proportion of CCL2/MCP-1-immunoreactive astrocytes and macrophages/microglia compared to wild-type counterparts. In knockout mice, neither Tat alone nor in combination with morphine increased the proportion of CCL2-immunoreactive astrocytes above percentages seen in vehicle-injected controls. Macrophages/microglia differed showing modest, albeit significant, increases in the proportion of CCL2-positive cells with combined Tat and morphine exposure, suggesting that CCL5 preferentially affects CCL2 expression by astroglia. Thus, CCL5 mediates glial activation caused by Tat and morphine, thereby aggravating HIV-1 neuropathogenesis in opiate abusers and non-abusers. CCL5 is implicated as mediating the cytokine-driven amplification of CCL2 production by astrocytes and resultant macrophage/microglial recruitment and activation.

Anti-CD3 activation of human CD4+ T cells increases expression of the intracellular beta-endorphin endopeptidase (IDE/gamma-EpGE)

In this study, increased expression of an endopeptidase hydrolyzing beta-endorphin (beta-Ep) to gamma-endorphin (gamma-Ep, beta-Ep1-17) was observed upon immobilized anti-CD3 stimulated activation of human peripheral blood CD4+ T cells (hCD4+ T cells). Although freshly isolated hCD4+ T cells are devoid of significant beta-Ep endopeptidase activity ( < 0.1 nmol h(-1) 10(6) cells (-1)), activation of these cells with immobilized anti-CD3 results in a time dependent appearance of beta-Ep endopeptidase activity which reaches a maximal value of 17.4+/-0.48 nmol h(-1) 10(6) cells(-1) after 48 h of culture. Significant up-regulation of both mRNA encoding IDE/gamma-EpGE and immunoreactive protein are observed in anti-CD3 stimulated hCD4+ T cells, indicating transcription and translation of IDE/gamma-EpGE may be elevated. No significant hydrolysis of exogenous beta-Ep is observed with intact hCD4+ T cells whether quiescent or activated or from preparations of hCD4+ T cell membranes. Therefore, this activity appears to be intracellular. Immunoreactive IDE/gamma-EpGE is detected inside activated hCD4+ T cells. Analysis of metabolites generated upon hydrolysis of beta-Ep with lysed activated hCD4+ T cell preparations identified the presence of: beta-Ep1-18, beta-Ep2-18, beta-Ep1-17, beta-Ep2-17, beta-Ep18-31, beta-Ep19-31, beta-Ep1-13, beta-Ep2-13, beta-Ep18-26, and beta-Ep20-31 as major metabolites and the majority of these are consistent with beta-Ep hydrolytic activity attributable to IDE/gamma-EpGE.