Medical Faculty, Institute of Inflammation and Neurodegeneration, Otto-von-Guericke University Magdeburg, Magdeburg, Germany.
Faculty of Life Sciences, Institute of Biology, Humboldt University, Berlin, Germany.
Front Cell Infect Microbiol. 2019 May 28;9:154. doi: 10.3389/fcimb.2019.00154. eCollection 2019.
Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) is an endogenous neuropeptide with distinct functions including the regulation of inflammatory processes. PACAP is able to modify the immune response by directly regulating macrophages and monocytes inhibiting the production of inflammatory cytokines, chemokines and free radicals. Here, we analyzed the effect of exogenous PACAP on peripheral immune cell subsets upon acute infection with the parasite . PACAP administration was followed by diminished innate immune cell recruitment to the peritoneal cavity of -infected mice. PACAP did not directly interfere with parasite replication, instead, indirectly reduced parasite burden in mononuclear cell populations by enhancing their phagocytic capacity. Although proinflammatory cytokine levels were attenuated in the periphery upon PACAP treatment, interleukin (IL)-10 and Transforming growth factor beta (TGF-β) remained stable. While PACAP modulated VPAC1 and VPAC2 receptors in immune cells upon binding, it also increased their expression of brain-derived neurotrophic factor (BDNF). In addition, the expression of p75 neurotrophin receptor (p75) on Ly6C inflammatory monocytes was diminished upon PACAP administration. Our findings highlight the immunomodulatory effect of PACAP on peripheral immune cell subsets during acute , providing new insights about host-pathogen interaction and the effects of neuropeptides during inflammation.
垂体腺苷酸环化酶激活肽(PACAP)是一种内源性神经肽,具有多种功能,包括调节炎症过程。PACAP 能够通过直接调节巨噬细胞和单核细胞来抑制炎症细胞因子、趋化因子和自由基的产生,从而改变免疫反应。在这里,我们分析了外源性 PACAP 在寄生虫急性感染时对周围免疫细胞亚群的影响。PACAP 的给药导致感染小鼠腹腔内固有免疫细胞募集减少。PACAP 并没有直接干扰寄生虫的复制,而是通过增强其吞噬能力,间接降低单核细胞群体中的寄生虫负担。虽然 PACAP 治疗后外周细胞因子水平降低,但白细胞介素(IL)-10 和转化生长因子-β(TGF-β)仍保持稳定。虽然 PACAP 在与免疫细胞结合时调节 VPAC1 和 VPAC2 受体,但它也增加了其脑源性神经营养因子(BDNF)的表达。此外,PACAP 给药后 Ly6C 炎性单核细胞上的 p75 神经生长因子受体(p75)表达减少。我们的研究结果强调了 PACAP 在急性感染期间对周围免疫细胞亚群的免疫调节作用,为宿主-病原体相互作用和炎症期间神经肽的作用提供了新的见解。