Abraham Mabel N, Nedeljkovic-Kurepa Ana, Fernandes Tiago D, Yaipen Omar, Brewer Mariana R, Leisman Daniel E, Taylor Matthew D, Deutschman Clifford S
Department of Pediatrics, Cohen Children's Medical Center, Northwell Health, New Hyde Park, New York, USA.
Sepsis Research Laboratories, The Feinstein Institutes for Medical Research, Northwell Health, Room 3140, 350 Community Drive, Manhasset, NY, 11030, USA.
Mol Med. 2024 Feb 5;30(1):22. doi: 10.1186/s10020-024-00787-x.
The contribution of the central nervous system to sepsis pathobiology is incompletely understood. In previous studies, administration of endotoxin to mice decreased activity of the vagus anti-inflammatory reflex. Treatment with the centrally-acting M1 muscarinic acetylcholine (ACh) receptor (M1AChR) attenuated this endotoxin-mediated change. We hypothesize that decreased M1AChR-mediated activity contributes to inflammation following cecal ligation and puncture (CLP), a mouse model of sepsis.
In male C57Bl/6 mice, we quantified basal forebrain cholinergic activity (immunostaining), hippocampal neuronal activity, serum cytokine/chemokine levels (ELISA) and splenic cell subtypes (flow cytometry) at baseline, following CLP and following CLP in mice also treated with the M1AChR agonist xanomeline.
At 48 h. post-CLP, activity in basal forebrain cells expressing choline acetyltransferase (ChAT) was half of that observed at baseline. Lower activity was also noted in the hippocampus, which contains projections from ChAT-expressing basal forebrain neurons. Serum levels of TNFα, IL-1β, MIP-1α, IL-6, KC and G-CSF were higher post-CLP than at baseline. Post-CLP numbers of splenic macrophages and inflammatory monocytes, TNFα and ILβ neutrophils and ILβ monocytes were higher than baseline while numbers of central Dendritic Cells (cDCs), CD4 and CD8 T cells were lower. When, following CLP, mice were treated with xanomeline activity in basal forebrain ChAT-expressing neurons and in the hippocampus was significantly higher than in untreated animals. Post-CLP serum concentrations of TNFα, IL-1β, and MIP-1α, but not of IL-6, KC and G-CSF, were significantly lower in xanomeline-treated mice than in untreated mice. Post-CLP numbers of splenic neutrophils, macrophages, inflammatory monocytes and TNFα neutrophils also were lower in xanomeline-treated mice than in untreated animals. Percentages of IL-1β neutrophils, IL-1β monocytes, cDCs, CD4 T cells and CD8 T cells were similar in xanomeline-treated and untreated post-CLP mice.
Our findings indicate that M1AChR-mediated responses modulate CLP-induced alterations in serum levels of some, but not all, cytokines/chemokines and affected splenic immune response phenotypes.
中枢神经系统对脓毒症病理生物学的作用尚未完全明确。在先前的研究中，给小鼠注射内毒素会降低迷走神经抗炎反射的活性。使用中枢作用的M1毒蕈碱型乙酰胆碱（ACh）受体（M1AChR）进行治疗可减弱这种内毒素介导的变化。我们推测，M1AChR介导的活性降低促成了盲肠结扎和穿刺（CLP）（一种脓毒症小鼠模型）后的炎症反应。
在雄性C57Bl/6小鼠中，我们在基线、CLP后以及CLP后并用M1AChR激动剂占诺美林治疗的小鼠中，对基底前脑胆碱能活性（免疫染色）、海马神经元活性、血清细胞因子/趋化因子水平（酶联免疫吸附测定）和脾细胞亚型（流式细胞术）进行了定量分析。
CLP后48小时，表达胆碱乙酰转移酶（ChAT）的基底前脑细胞的活性是基线时观察到的活性的一半。在海马中也观察到较低的活性，海马包含来自表达ChAT的基底前脑神经元的投射。CLP后血清中TNFα、IL-1β、MIP-1α、IL-6、KC和G-CSF的水平高于基线。CLP后脾巨噬细胞、炎性单核细胞、TNFα和ILβ中性粒细胞以及ILβ单核细胞的数量高于基线，而中枢树突状细胞（cDC）、CD4和CD8 T细胞的数量较低。CLP后，用占诺美林治疗的小鼠中，表达ChAT的基底前脑神经元和海马中的活性显著高于未治疗的动物。CLP后，占诺美林治疗的小鼠血清中TNFα、IL-1β和MIP-1α的浓度显著低于未治疗的小鼠，但IL-6、KC和G-CSF的浓度并非如此。CLP后，占诺美林治疗的小鼠脾中性粒细胞、巨噬细胞、炎性单核细胞和TNFα中性粒细胞的数量也低于未治疗的动物。在CLP后接受占诺美林治疗和未治疗的小鼠中，IL-1β中性粒细胞、IL-1β单核细胞、cDC、CD4 T细胞和CD8 T细胞的百分比相似。
我们的研究结果表明，M1AChR介导的反应调节CLP诱导的某些（但不是全部）细胞因子/趋化因子血清水平变化，并影响脾脏免疫反应表型。
