Adult zymosan re-exposure exacerbates the molecular alterations in the brainstem rostral ventromedial medulla of rats with early life zymosan-induced cystitis.

Recent evidence suggests that the descending modulatory pathways from the brainstem rostral ventromedial medulla (RVM) are important for bladder inflammatory pain. This study aimed to identify the long-term molecular changes in RVM neurons due to early life cystitis during neuronal development and the effect of reexposure later in adulthood. RVM tissues from two treatment protocols were used: (1) neonatal zymosan exposures with acute adult rechallenge (RC) and (2) only neonatal zymosan exposures (NRC). RNAseq analysis showed upregulation of several genes associated with synaptic plasticity (Grin1, Grip2, Notch1, Arc, and Scn2b) in the cystitis groups compared to controls in both protocols. The RC protocol exhibited a stronger treatment effect with significantly higher fold differences between the groups compared to the NRC protocol (p<0.001, fold differences RC vs NRC). In microarrays, miR-34a-5p showed cystitis-induced downregulation in both protocols. Bioinformatics analysis identified multiple 3’UTRs complementary binding sites for miR-34a-5p on Grin2b, Notch1, Grip2, Scn2b, and Arc genes. The enhanced response in the RC protocol indicates a possible priming effect of early life cystitis on rechallenge in adulthood. These long-term molecular alterations may play a critical role in the development of chronic bladder pain conditions as seen in patients with Interstitial Cystitis/Bladder pain syndrome近期研究证据表明，源自脑干延髓嘴侧腹内侧（rostral ventromedial medulla, RVM）的下行调节通路在膀胱炎性疼痛中发挥关键作用。本研究旨在明确神经元发育阶段早期膀胱炎所引发的RVM神经元长期分子改变，以及成年后再次暴露的影响效应。本研究使用了两种处理方案的RVM组织样本：(1) 新生酵母多糖暴露联合成年急性再激发组（RC组）；(2) 仅新生酵母多糖暴露组（NRC组）。RNA测序（RNAseq）分析显示，相较于对照组，两种处理方案的膀胱炎组均出现多个与突触可塑性相关基因的上调，包括Grin1、Grip2、Notch1、Arc及Scn2b。与NRC组相比，RC组的处理效应更强，组间差异倍数显著更高（p<0.001，RC组与NRC组差异倍数对比）。基因芯片检测结果显示，miR-34a-5p在两种膀胱炎处理方案中均呈现膀胱炎诱导的表达下调。生物信息学分析发现，Grin2b、Notch1、Grip2、Scn2b及Arc基因上存在多个与miR-34a-5p互补结合的3'非翻译区（3’ untranslated regions, 3’UTRs）位点。RC组的应答增强提示，早期膀胱炎可能对成年后的再激发存在致敏效应。上述长期分子改变可能在间质性膀胱炎/膀胱疼痛综合征（Interstitial Cystitis/Bladder Pain Syndrome）患者所表现出的慢性膀胱疼痛病症的发生发展中扮演关键角色。