Hendler Blake J, McClain Jonathon L, Zilli Aurora, Seguella Luisa, Gulbransen Brian D
Department of Physiology, Michigan State University, 567 Wilson Road, East Lansing, MI, 48824, USA.
Department of Physiology and Pharmacology "V. Erspamer", Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.
Purinergic Signal. 2024 Nov 29. doi: 10.1007/s11302-024-10060-9.
Purines are important mediators of intercellular communication in the enteric nervous system (ENS) that participate in physiological gut functions and disease. Purinergic transmission is prominent in mechanisms of crosstalk between enteric neurons and glia where enteric glia exhibit high responsiveness to adenosine diphosphate (ADP) through P2Y receptors and neurons to adenosine triphosphate (ATP) through P2X receptors. Despite functional data suggesting that enteric glia are the primary site of P2Y expression in the ENS, gene sequencing suggests that P2Y expression is more enriched in neurons than glia. The reason for the mismatch between genomic and functional data is unclear but could involve co-expression of inhibitory P2Y receptors in neurons. We addressed this issue by studying the expression and function of P2Y and P2Y receptors in the mouse ENS using live immunolabeling and calcium imaging techniques. The data show that ADP drives activity among enteric glia and neurons in the myenteric plexus. Interestingly, inhibiting P2Y activity increased neuron responses to ADP and overall spontaneous activity among enteric neurons and glia while decreasing the magnitude of glial responses to ADP. Investigating the location of the receptors involved revealed P2Y receptor expression by both neurons and glia, while P2Y receptor expression was minimal in the ENS. Instead, P2Y expression was enriched in the surrounding muscularis macrophages. Macrophages positive for P2Y overlapped with CD163 positive subsets that have known inhibitory influences over myenteric neurocircuits. Together, these data suggest that macrophage P2Y pathways act to constrain activity in the ENS, which could have implications in mechanisms that contribute to enteric hyperexcitability following disease.
嘌呤是肠神经系统（ENS）中细胞间通讯的重要介质，参与肠道生理功能和疾病过程。嘌呤能传递在肠神经元与神经胶质细胞的串扰机制中很突出，其中肠神经胶质细胞通过P2Y受体对二磷酸腺苷（ADP）表现出高反应性，而神经元通过P2X受体对三磷酸腺苷（ATP）表现出高反应性。尽管功能数据表明肠神经胶质细胞是ENS中P2Y表达的主要部位，但基因测序表明P2Y在神经元中的表达比神经胶质细胞中更丰富。基因组数据与功能数据不匹配的原因尚不清楚，但可能涉及神经元中抑制性P2Y受体的共表达。我们通过使用实时免疫标记和钙成像技术研究小鼠ENS中P2Y和P2Y受体的表达和功能来解决这个问题。数据显示，ADP驱动肌间神经丛中肠神经胶质细胞和神经元的活动。有趣的是，抑制P2Y活性会增加神经元对ADP的反应以及肠神经元和神经胶质细胞的整体自发活动，同时降低神经胶质细胞对ADP反应的幅度。对相关受体位置的研究表明，神经元和神经胶质细胞均表达P2Y受体，而ENS中P2Y受体的表达极少。相反，P2Y在周围肌层巨噬细胞中表达丰富。P2Y阳性的巨噬细胞与已知对肌间神经回路有抑制作用的CD163阳性亚群重叠。总之，这些数据表明巨噬细胞P2Y途径起到限制ENS活动的作用，这可能对疾病后导致肠道过度兴奋的机制有影响。
