Morphine upregulates mu opioid receptors of human and monkey lymphocytes

Opioid receptors of subtypes delta, kappa, and mu similar to those found in brain cells have been identified in immune cells. The current study demonstrates by competitive polymerase chain reaction the treatment of human lymphocytic cells with morphine resulting in an increased amount of gene expression of mu opioid receptors. Antibodies against the MOR-1, the neuronal mu opioid receptor, were used in Western blot analysis of mu proteins and the results revealed a single band of approximately 50 kDa, the intensity of which was increased by morphine treatment. Similar results of mu opioid receptor activation were observed when monkey lymphocytes were treated with morphine. These studies suggest that in addition to causing an immune effect through communication with the neuroendocrine system, the psychoactive drug morphine may modulate immune functions by acting directly on the mu opioid receptors expressed on lymphocytes.     

本氏烟Ⅰ型启动子的克隆及其转录起始位点分析

启动子是转录水平上一个重要的调控元件,其决定着基因的表达模式和表达强度。Ⅰ型启动子具有高转录活性和种属间特异性等特点。如将其应用于植物RNA病毒载体表达系统,有利于提高表达系统的表达效率和生物安全性。本氏烟(Nicotiana benthaminana)是一种被广泛地应用于植物生物反应器和植物病理学的模式生物,但是现有核酸数据库中尚没有其Ⅰ型启动子的相关信息。因此,克隆本氏烟Ⅰ型启动子并分析其转录起始位点就具有重要的应用价值。通过半巢式PCR获得了514 bp的本氏烟Ⅰ型启动子序列(KC352713);生物信息学分析初步预测其转录起始位点位于其核心序列TATA(G)TA(N)GGGGG中的第3位A处;通过植物RNA病毒表达载体和5'RACE技术在体内验证本氏烟Ⅰ型启动子转录起始位点与生物信息学预测结果一致。研究结果为深入研究Ⅰ型启动子和构建Ⅰ型启动子介导转录的植物RNA病毒载体表达系统奠定了基础。     

Interactions of Opioid and Chemokine Receptors: Oligomerization of mu, kappa, and delta with CCR5 on Immune Cells

Activation of opioid receptors by morphine was previously shown to specifically induce the expression of chemokine receptor CCR5, promoting simian AIDS virus entry and replication in immune cells. The present study was undertaken to determine whether these two structurally and functionally distinct G-protein-coupled receptors are in close proximity and form an oligomeric complex in the cell membrane so that the activation of one triggers the activity of the other. Both human CEM ×174 and monkey lymphocytes were used in this study and gave similar results. Immunoprecipitation experiments showed that CCR5, but not CD4 nor Na⁺/H⁺ exchanger, coprecipitates with all three subtypes (mu, delta, and kappa) of opioid receptors. A single protein band immunoreactive with antibodies against both the CCR5 and the opioid receptors was identified after electrophoresis on nondenaturing polyacrylamide gels. Chemical crosslinking experiments using glutaraldehyde or BS³ indicate that these receptors are closely situated on the cell membrane with an intermolecular distance less than 11.4Å. Functional studies revealed that a combination treatment of cells with morphine, an agonist for mu, and MIP-1β, a ligand for CCR5, suppresses the inhibitory effect of MIP-1β and increases the stimulatory effect of morphine on CCR5 expression. These results suggest that oligomerization of chemokine receptor CCR5 and opioid receptors on the cell membrane of human or monkey lymphocytes may modulate receptor functions.