Antinociceptive effects of central administration of the endogenous cannabinoid receptor type 1 agonist VDPVNFKLLSH-OH [(m)VD-hemopressin(α)], an N-terminally extended hemopressin peptide.

The cannabinoid system has been demonstrated to modulate the acute and chronic pain of multiple origins. Mouse VD-hemopressin(α) [(m)VD-Hpα], an 11-residue α-hemoglobin-derived peptide, was recently reported to function as a selective agonist of the cannabinoid receptor type 1 (CB1) in vitro. To characterize its behavioral and physiological properties, we investigated the in vivo effects of (m)VD-Hpα in mice. In the mouse tail-flick test, (m)VD-Hpα dose-dependently induced antinociception after supraspinal (EC50 = 6.69 nmol) and spinal (EC50 = 2.88 nmol) administration. The antinociceptive effects of (m)VD-Hpα (intracerebroventricularly and intrathecally) were completely blocked by N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3- carboxamide (AM251; CB1 antagonist), but not by 6-iodo-2-methyl-1-[2-(4-morpholinyl)ethyl]-1H-indol-3-yl(4-methoxyphenyl)-methanone (AM630; CB2 antagonist) or naloxone (opioid antagonist), showing its selectivity to the CB1 receptor. Furthermore, the central nervous system (CNS) effects of (m)VD-Hpα were evaluated in body temperature, locomotor activity, tolerance development, reward, and food intake assays. At the highly antinociceptive dose (3 × EC50), (m)VD-Hpα markedly exerted hypothermia and hypoactivity after supraspinal administration. Repeated intracerebroventricular injection of (m)VD-Hpα resulted in both development of tolerance to antinociception and conditioned place aversion. In addition, central injection of (m)VD-Hpα dose-dependently stimulated food consumption. These findings demonstrate that this novel cannabinoid peptide agonist induces CB1-mediated central antinociception with some CNS effects, which further supports a CB1 agonist character of (m)VD-Hpα. Moreover, the current study will be helpful to understand the in vivo properties of the endogenous peptide agonist of the cannabinoid CB1 receptor.

Enriched HLA-E and CD94/NKG2A Interaction Limits Antitumor CD8+ Tumor-Infiltrating T Lymphocyte Responses.

Immunotherapy treatments with anti-PD-1 boost recovery in less than 30% of treated cancer patients, indicating the complexity of the tumor microenvironment. Expression of HLA-E is linked to poor clinical outcomes in mice and human patients. However, the contributions to immune evasion of HLA-E, a ligand for the inhibitory CD94/NKG2A receptor, when expressed on tumors, compared with adjacent tissue and peripheral blood mononuclear cells, remains unclear. In this study, we report that epithelial-derived cancer cells, tumor macrophages, and CD141+ conventional dendritic cells (cDC) contributed to HLA-E enrichment in carcinomas. Different cancer types showed a similar pattern of enrichment. Enrichment correlated to NKG2A upregulation on CD8+ tumor-infiltrating T lymphocytes (TIL) but not on CD4+ TILs. CD94/NKG2A is exclusively expressed on PD-1high TILs while lacking intratumoral CD103 expression. We also found that the presence of CD94/NKG2A on human tumor-specific T cells impairs IL2 receptor-dependent proliferation, which affects IFNγ-mediated responses and antitumor cytotoxicity. These functionalities recover following antibody-mediated blockade in vitro and ex vivo Our results suggest that enriched HLA-E:CD94/NKG2A inhibitory interaction can impair survival of PD-1high TILs in the tumor microenvironment.

Human Leukocyte Antigen-A Allele Distribution in Nasopharyngeal Carcinoma Patients Showing Anti-Melanoma-Associated Antigen A or Synovial Sarcoma X-2 T Cell Response in Blood.

BACKGROUND: Development of innovative immunotherapy is imperative to improve the poor survival of the nasopharyngeal carcinoma (NPC) patients. In this study, we evaluated the T cell response to melanoma-associated antigen (MAGE)-A1, MAGE-A3, or synovial sarcoma X-2 (SSX-2) in the peripheral blood of treatment-naive NPC patients. The relationship of responses among the three proteins and the human leukocyte antigen (HLA)-A types were analyzed to provide evidence of designing novel therapy. METHODS: Sixty-one NPC patients admitted into the Tumor Hospital affiliated to the Xinjiang Medical University between March 2015 and July 2016 were enrolled. Mononuclear cells were isolated from the peripheral blood before any treatment. HLA-A alleles were typed with Sanger sequence-based typing technique. The T cell response to the MAGE-A1, MAGE-A3, or SSX-2 was evaluated with the Enzyme-Linked ImmunoSpot assay. Mann-Whitney U-test was used to compare the T cell responses from different groups. Spearman's rank correlation was used to analyze the relationship of T cell responses. RESULTS: HLA-A*02:01, A*02:07, and A*24:02 were the three most frequent alleles (18.9%, 12.3%, and 11.5%, respectively) among the 22 detected alleles. 31.1%, 19.7%, and 16.4% of the patients displayed MAGE-A1, MAGE-A3, or SSX-2-specific T cell response, respectively. The magnitudes of response to the three proteins were 32.5, 38.0, and 28.7 SFC/106 peripheral blood mononuclear cells, respectively. The T cell response against the three proteins correlated with each other to different extent. The percentage of A*02:01 and A*24:02 carriers were significantly higher in patients responding to any of the three proteins compared to the nonresponders. CONCLUSION: MAGE-A1, MAGE-A3, or SSX-2-specific T cell responses were detectable in a subgroup of NPC patients, the frequency and magnitude of which were correlated.

The hypotensive effect of intrathecally injected (m)VD-hemopressin(α) in urethane-anesthetized rats.

Previous studies suggest that cannabinoids system plays an important role in cardiovascular regulation. (m)VD-hemopressin(α) (VD-Hpα), an 11-residue peptide originating from the α1 chain of hemoglobin, was recently reported as a selective agonist of cannabinoid CB1 receptor. The present study was undertaken to investigate the intrathecal (i.t.) action of (m)VD-Hpα on blood pressure in urethane-anesthetized rats. Our results demonstrated that injections of (m)VD-Hpα (5-30 nmol, i.t.) produced a dose-dependent decrease in mean arterial pressure (MAP), similar to that of the non-peptidic cannabinoid receptor agonist WIN55212-2 (1.25-10 nmol, i.t.). The hypotensive effect of (m)VD-Hpα was not influenced by the CB1 receptor antagonist AM251 (20 nmol, i.t.) or the CB2 receptor antagonist AM630 (20 nmol, i.t.). However, WIN55212-2-induced hypotension was almost completely prevented by i.t. administration of AM251, not by AM630. The spinal hypotension of (m)VD-Hpα and WIN55212-2 was significantly reduced by pretreatment with the α-adrenoceptor antagonist phentolamine (1 mg/kg, i.v.), but not by the ß-adrenoceptor antagonist propranolol (2 mg/kg, i.v.) or the muscarinic receptor antagonist atropine (2 mg/kg, i.v.). In addition, L-NAME (50 mg/kg, i.v.), the inhibitor of nitric oxide (NO) synthase, significantly reduced WIN55212-2-induced hypotension, but had no effect on the hypotensive response to (m)VD-Hpα. Collectively, the results show that i.t. administration of (m)VD-Hpα induces a decrease in MAP via a non-CB1 and non-CB2 mechanism.

Opposite effects of neuropeptide FF on central antinociception induced by endomorphin-1 and endomorphin-2 in mice.

Neuropeptide FF (NPFF) is known to be an endogenous opioid-modulating peptide. Nevertheless, very few researches focused on the interaction between NPFF and endogenous opioid peptides. In the present study, we have investigated the effects of NPFF system on the supraspinal antinociceptive effects induced by the endogenous µ-opioid receptor agonists, endomorphin-1 (EM-1) and endomorphin-2 (EM-2). In the mouse tail-flick assay, intracerebroventricular injection of EM-1 induced antinociception via µ-opioid receptor while the antinociception of intracerebroventricular injected EM-2 was mediated by both µ- and κ-opioid receptors. In addition, central administration of NPFF significantly reduced EM-1-induced central antinociception, but enhanced EM-2-induced central antinociception. The results using the selective NPFF1 and NPFF2 receptor agonists indicated that the EM-1-modulating action of NPFF was mainly mediated by NPFF2 receptor, while NPFF potentiated EM-2-induecd antinociception via both NPFF1 and NPFF2 receptors. To further investigate the roles of µ- and κ-opioid systems in the opposite effects of NPFF on central antinociception of endomprphins, the µ- and κ-opioid receptors selective agonists DAMGO and U69593, respectively, were used. Our results showed that NPFF could reduce the central antinociception of DAMGO via NPFF2 receptor and enhance the central antinociception of U69593 via both NPFF1 and NPFF2 receptors. Taken together, our data demonstrate that NPFF exerts opposite effects on central antinociception of endomorphins and provide the first evidence that NPFF potentiate antinociception of EM-2, which might result from the interaction between NPFF and κ-opioid systems.