July 28, 2021
1997;100:825C831. + IL18. Finally, the long-acting ADRB2-specific agonist, salmeterol, markedly reduced the cytokine secretion capacity of CD8+ T cells in response to NS1 contamination with vesicular stomatitis computer virus. This study reveals a novel intrinsic role for ADRB2 signaling in CD8+ T-cell function and underscores the novel role this pathway plays in adaptive T-cell responses to infection. decided the effect of chemical sympathectomy with 6-hydroxydopamine on anti-influenza CD8+ T-cell responses . In their study, blocking the secretion of NE before influenza contamination increased the IFN-+CD8+ T-cell response, and blocking ADRB2 signaling with ADRB2-specific antagonists paralleled their observations in sympathectomized animals. Kalinichenko and transcripts were quantified by qPCR. (C) Splenocytes from Cl4 mice were incubated overnight with the HA peptide IYSTVASSL, in the absence of exogenous IL-2 and in the presence or absence of NE. IL-2, IFN- and TNF- were measured from the supernatants at 24 hours. (D) Splenocytes from Cl4 mice were incubated with the HA peptide IYSTVASSL in the presence or absence of albuterol or NE. IFN- and TNF- in the supernatants were measured at 18 hours. (D) CD8+ T cells from Balb/cJ mice were activated as in (A), in the presence of albuterol or NE and in the presence of milliQ water (Ctrl), or a pan- (phentolamine), a pan- (nadolol), a 1-specific (atenolol), or a 2-specific (ICI-118,551) adrenergic receptor antagonist (100 nM each). IFN- (not shown) and TNF- in the supernatants were measured. (E) CD8+ T cells from ADRB2+/+ or ADRB2?/? Balb/cJ mice were isolated and activated as in (A), in the presence of Methazolastone increasing concentrations of NE or albuterol. IFN- (not shown) and TNF- in the supernatants were measured. Data are presented as mean +/? SEM of triplicate determinations and are representative of (A and D) 3 experiments, (B, E, and F) 2 experiments, and (C) 1 experiment. * p<0.05, **p<0.01, ***p<0.001, ****p<0.0001 compared to 0 M NE or media, by Students t-test (C), or 1-way (A, B, and D) or 2-way (E and F) ANOVA with Bonferroni post-test. NE suppresses CD8+ T-cell function independently of nicotinic acetylcholine Methazolastone receptor signaling Although ADRB2 signaling was required for cytokine suppression by NE, it was possible that the effects were indirect through the induction of a negative regulatory pathway. Indeed, Rosas-Ballina exhibited that memory-like CD4+ T cells could secrete acetylcholine in response to high concentrations of NE . Acetylcholine can decrease pro-inflammatory cytokine secretion of macrophages by signaling through the 7 nicotinic acetylcholine receptor [26C28]. To test whether NE was driving acetylcholine-mediated suppression of cytokine secretion, OT-I spleen cell suspensions were activated with the CD8+ T-cell specific ovalbumin peptide (SIINFEKL) in the presence or absence of NE and increasing concentrations of methyllycaconitine (an 7 nicotinic acetylcholine receptor antagonist). As shown, methyllycaconitine failed to revert the effect of NE, even at concentrations as high as 10 M (Fig. 4A). The ADRB2 signals through the adenylyl cyclase pathway in many cell types, and elevated cAMP levels have been shown to inhibit cytokine expression in CD4+ T cells [29, 30]. As expected, forskolin markedly suppressed TNF- secretion in CD8+ T cells in response to TCR stimulation (Fig. 4B). However, attempts to block this suppression with two distinct adenylyl cyclase inhibitors, 25-dideoxyadenosine and KH7, failed to reverse the inhibitory effects of NE on TNF- secretion. These results indicate that while cAMP mobilization profoundly blocks TCR-mediated cytokine expression, additional pathways may interface with adenylyl cyclase activation by NE to suppress CD8+ T-cell effector function. Nonetheless, that data support a direct role for ADRB2 signaling that does not require autocrine responses to acetylcholine. Open in a separate window Physique 4 ADRB2 signaling suppresses mouse CD8+ T-cell cytokine secretion impartial of acetylcholine or cAMP(A) Splenocytes from OT-I mice were isolated and incubated 23 hours with the OVA peptide SIINFEKL and NE with increasing concentrations of an 7 nicotinic receptor antagonist (methyllycaconitine) or a 2 adrenergic receptor antagonist (ICI-118,551). TNF- in the supernatants was Methazolastone measured. (B) Splenocytes from Cl4 mice were incubated overnight with the HA peptide IYSTVASSL and in the presence Methazolastone or absence of albuterol or increasing concentrations of the cAMP stimulator forskolin. IFN- and TNF- were measured. (C) Splenocytes from Cl4 mice were incubated with HA peptide in the presence or absence of NE, and Methazolastone with increasing concentrations of an adenylyl cyclase inhibitor (25-dideoxyadenosine;).