Regulation of nuclear factor of activated T cells by phosphotyrosyl-specific phosphatase activity: a positive effect on HIV-1 long terminal repeat-driven transcription and a possible implication of SHP-1.

Although protein tyrosine phosphatase (PTP) inhibitors used in combination with other stimuli can induce interleukin 2 (IL-2) production in T cells, a direct implication of nuclear factor of activated T cells (NFAT) has not yet been demonstrated. This study reports that exposure of leukemic T cells and human peripheral blood mononuclear cells to bis-peroxovanadium (bpV) PTP inhibitors markedly induce activation and nuclear translocation of NFAT. NFAT activation by bpV was inhibited by the immunosuppressive drugs FK506 and cyclosporin A, as well as by a specific peptide inhibitor of NFAT activation. Mobility shift assays showed specific induction of the NFAT1 member by bpV molecules. The bpV-mediated NFAT activation was observed to be important for the up-regulation of the human immunodeficiency virus 1 (HIV-1) long terminal repeat (LTR) and the IL-2 promoter; NFAT1 was demonstrated to be particularly important in bpV-dependent positive action on HIV-1 LTR transcription. The active participation of p56(lck), ZAP-70, p21(ras), and calcium in the bpV-mediated signaling cascade leading to NFAT activation was confirmed, using deficient cell lines and dominant-negative mutants. Finally, overexpression of wild-type SHP-1 resulted in a greatly diminished activation of NFAT by bpV, suggesting an involvement of SHP-1 in the regulation of NFAT activation. These data were confirmed by constitutive NFAT translocation observed in Jurkat cells stably expressing a dominant-negative version of SHP-1. The study proposes that PTP activity attenuates constitutive kinase activities that otherwise would lead to constant NFAT activation and that this activation is participating in HIV-1 LTR stimulation by PTP inhibition.

Effect of MPTP-induced denervation on basal ganglia GABA(B) receptors: correlation with dopamine concentrations and dopamine transporter.

We investigated the effect of MPTP-induced lesion of the substantia nigra pars compacta (SNpc) dopaminergic neurons on GABA(B) receptors in the basal ganglia of mice and monkeys using receptor autoradiography and in situ hybridization. The extent of the lesion was measured with striatal catecholamine content, striatal binding of (125)I-RTI-121 to dopamine transporter (DAT), and DAT expression in the SNpc. GABA(B) receptors in mice brain were evaluated using (3)H-CGP54626 and its expression was measured with oligonucleotides probes targeting the mRNAs of GABA(B(1a+b)), GABA(B(1a)), GABA(B(1b)), GABA(B(2)) subunits. In monkeys, (125)I-CGP64213 and selective probes for GABA(B(1a+b)) and GABA(B(2)) mRNAs were used. In mice, dopamine content, (125)I-RTI-121 binding, and DAT expression were reduced by 44%, 40%, and 39% after a dose of 40 mg/kg of MPTP and 74%, 70%, and 34% after 120 mg/kg of MPTP, respectively. In monkeys, dopamine content and DAT expression were decreased by more than 90% and 80%, respectively. In the striatum and the subthalamic nucleus, GABA(B) receptors were unchanged following MPTP in both species. In the SNpc of mice, MPTP (120 mg/kg) induced a significant decrease of (3)H-CGP54626 binding (-10%) and of the expression of GABA(B(1a+b)) mRNA (-13%). The decrease of the expression of GABA(B(1a+b)) mRNA was correlated with dopamine content, (125)I-RTI-121 binding and DAT expression. In MPTP-treated monkeys, (125)I-CGP64213 binding (-40%), GABA(B(1a+b)) mRNA (-69%) and GABA(B(2)) mRNA (-66%) were also significantly decreased in the SNpc. Our results suggest that MPTP-induced denervation is associated with a decrease of GABA(B) receptors restricted to the SNpc. These observations may be relevant to the pathophysiology of motor disorders involving dysfunction of the basal ganglia such as Parkinson disease.

Increased tumor necrosis factor-alpha production by peripheral blood leukocytes from TCDD-exposed rhesus monkeys.

Previous work has shown that exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is associated with a dose-dependent increase in the incidence and severity of endometriosis in the rhesus monkey. Studies also suggest that immune mechanisms participate in TCDD-mediated toxicity and the pathogenesis of endometriosis. Thirteen years after TCDD treatment was terminated, we characterized the phenotypic distribution of peripheral blood mononuclear cells (PBMC) from TCDD-exposed and -unexposed rhesus monkeys and determined the ability of these cells to produce cytokines and exert cytolytic activity against NK and T-cell-sensitive cell lines. We also determined whether elevated serum levels of TCDD, dioxin-like PHAH congeners, and triglycerides correlated with changes in PBMC phenotype or function. For all animals, TCDD exposure correlated with increased PBMC tumor necrosis factor-alpha (TNF-alpha) secretion in response to stimulation by T-cell mitogen and decreased cytolytic activity against NK-sensitive target cells. Furthermore, increased production of this cytokine by PHA-stimulated leukocytes was associated with elevated serum triglyceride levels. Leukocyte TNF-alpha secretion in response to viral antigen and PBMC production of interferon gamma (IFNgamma), IL-6, and IL-10 following exposure to mitogen or antigen were unaffected by previous TCDD treatment. Although TCDD exposure was not associated with changes in PBMC surface antigen expression, elevated serum concentrations of TCDD, 1,2,3,6,7,8-hexachlorodibenzofuran and 3,3',4,4',5-pentachlorobiphenyl correlated with increased numbers of CD3+/CD25- and CD3-/CD25+ leukocytes and enhanced secretion of TNF-alpha by mitogen-stimulated PBMC. These findings indicate that TCDD-exposed rhesus monkeys with endometriosis exhibit long-term alterations in systemic immunity associated with elevated serum levels of specific PHAH congeners.

Profile of endometriosis in the aging female rhesus monkey.

BACKGROUND: A retrospective analysis was conducted on necropsy records from a large rhesus monkey colony to evaluate the age-related prevalence of endometriosis. METHODS: A total of 314 records collected over a 15-year period were analyzed, yielding 66 monkeys with histologically verified endometriosis and 248 control subjects. RESULTS: The analyses demonstrated that the incidence of endometriosis increases progressively across the life span, ultimately impacting 21-45% of aged monkeys over 20 years of age. CONCLUSIONS: Because mild disease is often not diagnosed premortem, the endocrine and immune sequelae of endometriosis may be a potential confound in even nonreproductive research with aging primates. Prior research-related events influence the occurrence and severity of endometriosis in these long-lived animals, and specifically could have contributed to the high prevalence of endometriosis in this particular monkey colony.

Surgical and psychological stressors differentially affect cytolytic responses in the rhesus monkey.

Four experiments were conducted in aged rhesus monkeys to investigate how physical and psychological stressors influence the lymphocyte cytolytic responses against two target cell lines. An initial analysis of the lytic activity of various cell subsets against K562 and RAJI target cell lines suggested that both CD3+CD8+ and several CD3- subsets were responsible for lysis of the K562 cells. The RAJI cell line, in contrast, was killed primarily by CD3-subsets. To explore the implications of this differential mediation of lysis, cytolytic activity was evaluated after a physical challenge (surgery), a psychological disturbance (social separation), and in vitro incubation of lymphocytes with cortisol. The minor surgical procedure-laparoscopic examination-resulted in a significant decrease in lymphocyte cytolytic responses against both target cells 1 week postsurgery. In contrast, psychological disturbance elicited by changes in social relations caused a dual response, differentially affecting the lysis of either K562 or RAJI cells, dependent upon the type of behavioral reaction. Incubation of lymphocytes with cortisol in vitro indicated that lysis of both targets could be affected by corticosteroids, but the high concentration required (10(-6) M) suggested that the in vivo inhibition of cytotoxicity may not have been mediated by adrenocortical activation. Overall, the results highlight the value of utilizing multiple target cell systems in the analysis of cytolytic activity, especially in studies using nonhuman primates.

Abuse-related posttraumatic stress disorder: evidence for chronic neuroendocrine activation in women.

The following study tested the hypothesis that women with post-traumatic stress disorder (PTSD) related to childhood sexual abuse would display elevated norepinephrine-to-cortisol ratios similar to that found in male combat veterans diagnosed with PTSD. Twenty-four-hour urine samples were collected from 28 women: 11 women with PTSD who experienced childhood sexual abuse (PTSD+), 8 women who experienced childhood sexual abuse without PTSD (PTSD-), and 9 nonabused controls. All urine samples were tested for creatinine, total catecholamines, free-cortisol, and 17-ketosteroid levels. Psychological testing validated that the PTSD+ group was significantly elevated on all three subscales of the Impact of Events Scale. Both abused groups (PTSD+ and PTSD-) showed a tendency for polyuria, and the PTSD+ group showed a tendency towards obesity. Thus, neuroendocrine values (micrograms/day) were adjusted by creatinine clearance rates (creatinine mg/day/kg body weight). The corrected values indicated that the PTSD+ group had significantly elevated daily levels of norepinephrine, epinephrine, dopamine, and cortisol. However, because of the parallel elevation in cortisol, the norepinephrine-to-cortisol ratio was not significantly elevated in the PTSD+ diagnosed women in contrast to the findings reported for male PTSD patients. This discrepancy may reflect an important gender difference, an interaction between gender and age at onset of the traumatic experience (childhood abuse in females vs. combat experience in young adult males), or physiological variation related to phase of the disorder.

Self-discrepancy and natural killer cell activity: immunological consequences of negative self-evaluation.

The study tested whether self-discrepancy theory could account for changes in natural killer (NK) cell activity after exposure to self-referential stimuli. Anxious, dysphoric, and control Ss were pretested and 1 month later covertly exposed to their own self-guides as well as those of another S. Blood samples were drawn for analysis of NK cytotoxicity and cortisol. The dysphoric Ss manifested the greatest actual:ideal discrepancy, whereas the anxious Ss manifested the greatest actual:ought discrepancy. Content analysis of written responses showed that activating discrepancies induced specific negative states; priming discrepancies also increased cortisol for the anxious Ss. NK activity was lower after self-referential priming for both distressed groups, particularly the anxious Ss. The control Ss showed a trend toward increased NK activity after self-referential priming. The study represents the 1st experimental demonstration that negative self-evaluation can alter immune responses.