Spatial transcriptome sequencing of the rat corpus cavernosum with normal erectile function

The composition and cellular heterogeneity of the corpus cavernosum (CC) microenvironment have been characterized, but the spatial heterogeneity at the molecular level and the evolutionary differences among species remain unexplored. In this study, we integrated single-cell RNA sequencing (scRNA-seq) and spatial transcriptome sequencing to comprehensively charted the spatial cellular landscape of human and rat CC under normal and disease conditions. We partitioned CC on the basis of special structures such as cavernous arteries, septum pectiniforme, and tunica albuginea, and described the spatial heterogeneity of cell composition and signaling networks in different regions. Additionally, we observed differences in the proportion of cell subtypes and marker genes among endothelial cells (EC), smooth muscle cells (SMC), and fibroblasts (FB) between humans and rats. Although many signalings involved in the basic biological processes such as translation are relatively conserved between human and rat, they show significant species differences in the pathways such as inflammatory response. Based on the analysis of FB niche, we also found that mechanical force signaling have significant spatial heterogeneity within CC and correlated with the spatial distribution of different FB subtypes. In vitro, soft and hard extracellular matrix (ECM) induced the differentiation of FB into APO+FB or COMP+FB subtype, respectively, and reprogrammed their lipid metabolism. In summary, our study provided a cross-species and physio-pathology transcriptomic atlas of the CC at the single-cell level with high spatial resolution, contributing to further understanding of the molecular anatomy and regulation of penile erection.目前学界已对阴茎海绵体（corpus cavernosum, CC）微环境的组成与细胞异质性完成了特征解析，但该微环境在分子层面的空间异质性以及不同物种间的演化差异仍有待探索。本研究整合单细胞RNA测序（single-cell RNA sequencing, scRNA-seq）与空间转录组测序技术，全面绘制了正常与疾病状态下人类及大鼠阴茎海绵体的空间细胞图谱。研究团队基于海绵体动脉、梳状隔（septum pectiniforme）与白膜（tunica albuginea）等特殊结构对阴茎海绵体进行分区，并阐明了不同区域内细胞组成与信号网络的空间异质性。此外，本研究观察到人类与大鼠在内皮细胞（endothelial cells, EC）、平滑肌细胞（smooth muscle cells, SMC）和成纤维细胞（fibroblasts, FB）的亚型占比与标记基因上存在显著物种差异。尽管参与翻译等基础生物学过程的诸多信号通路在人类与大鼠间相对保守，但二者在炎症反应等通路中却呈现出显著的物种特异性差异。通过对成纤维细胞微环境的分析，本研究还发现机械力信号通路在阴茎海绵体内存在显著空间异质性，且与不同成纤维细胞亚型的空间分布密切相关。体外实验表明，柔软与坚硬的细胞外基质（extracellular matrix, ECM）可分别诱导成纤维细胞分化为APO+成纤维细胞或COMP+成纤维细胞亚型，并重塑其脂质代谢模式。综上，本研究构建了具备高空间分辨率的单细胞水平跨物种生理-病理状态阴茎海绵体转录组图谱，为进一步解析阴茎勃起的分子解剖学机制与调控通路提供了重要研究基础。