Heterogeneity of fibroblasts is a hallmark of age-associated erectile dysfunction

Molecular and spatial signatures of human and rat corpus cavernosum physiopathological processes at single-cell resolution

The composition and cellular heterogeneity of the corpus cavernosum (CC) microenvironment have been characterized, but the spatial heterogeneity at the molecular level remains unexplored. In this study, we integrate single-cell RNA sequencing (scRNA-seq) and spatial transcriptome sequencing to comprehensively chart the spatial cellular landscape of the human and rat CC under normal and disease conditions. We observe differences in the proportions of cell subtypes and marker genes between humans and rats. Based on the analysis of the fibroblast (FB) niche, we also find that the enrichment scores of mechanical force signaling vary across different regions and correlate with the spatial distribution of FB subtypes. In vitro, the soft and hard extracellular matrix (ECM) induces the differentiation of FBs into apolipoprotein (APO)+ FBs and cartilage oligomeric matrix protein (COMP)+ FBs, respectively. In summary, our study provides a cross-species and physiopathological transcriptomic atlas of the CC, contributing to a further understanding of the molecular anatomy and regulation of penile erection.

Chronic prostatitis/chronic pelvic pain syndrome impairs erectile function by inducing apoptosis in a rat model of experimental autoimmune prostatitis

Over the years, numerous epidemiological studies have shown that chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) promotes erectile dysfunction. Nonetheless, the precise underlying mechanism remains to be fully clarified. The objective of this research was to identify crucial signaling pathways responsible for CP/CPPS-induced erectile dysfunction. Thirty 8-week-old male Sprague‒Dawley rats were randomly assigned to either the CP/CPPS model group or the control group. The CP/CPPS rat model was established through subcutaneous injection of a combination of rat prostate protein and Freund's adjuvant. Penile erectile function assessment was conducted 45 days after immunization through electrical stimulation of the cavernous nerve. RNA sequencing of the corpus cavernosum of the penis was then performed using the Kyoto Encyclopedia of Genes and Genomes and protein‒protein interaction network analysis. Western blotting was performed on the cavernous tissue. Cell apoptosis assays, cell counting kit-8 assays, cell cloning assays, and Western blotting were conducted on rat endothelial cells. Erectile function was significantly lower in the CP/CPPS model group than in the control group (p < 0.001). Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed that differentially expressed genes were predominantly enriched in the apoptosis pathway. Moreover, an increase in apoptosis in the rat corpus cavernosum, along with a decrease in the protein expression of CD31 (p = 0.0089) and eNOS (p = 0.0069) following CP/CPPS induction, was observed. In a protein‒protein interaction network, Pitx2 was recognized as a central gene. The role of Pitx2 in regulating apoptosis was demonstrated in experiments using rat endothelial cell lines, and it was found to be regulated by the Wnt/β-catenin pathway. This study highlights the occurrence of cavernous endothelial cell apoptosis in CP/CPPS-induced erectile dysfunction, and the potential mechanism of apoptosis may involve inhibition of the Wnt/β-catenin/Pitx2 pathway.

Single-cell transcriptome analysis of cavernous tissues reveals the key roles of pericytes in diabetic erectile dysfunction

Erectile dysfunction (ED) affects a significant proportion of men aged 40-70 and is caused by cavernous tissue dysfunction. Presently, the most common treatment for ED is phosphodiesterase 5 inhibitors; however, this is less effective in patients with severe vascular disease such as diabetic ED. Therefore, there is a need for development of new treatment, which requires a better understanding of the cavernous microenvironment and cell-cell communications under diabetic condition. Pericytes are vital in penile erection; however, their dysfunction due to diabetes remains unclear. In this study, we performed single-cell RNA sequencing to understand the cellular landscape of cavernous tissues and cell type-specific transcriptional changes in diabetic ED. We found a decreased expression of genes associated with collagen or extracellular matrix organization and angiogenesis in diabetic fibroblasts, chondrocytes, myofibroblasts, valve-related lymphatic endothelial cells, and pericytes. Moreover, the newly identified pericyte-specific marker, Limb Bud-Heart (Lbh), in mouse and human cavernous tissues, clearly distinguishing pericytes from smooth muscle cells. Cell-cell interaction analysis revealed that pericytes are involved in angiogenesis, adhesion, and migration by communicating with other cell types in the corpus cavernosum; however, these interactions were highly reduced under diabetic conditions. Lbh expression is low in diabetic pericytes, and overexpression of LBH prevents erectile function by regulating neurovascular regeneration. Furthermore, the LBH-interacting proteins (Crystallin Alpha B and Vimentin) were identified in mouse cavernous pericytes through LC-MS/MS analysis, indicating that their interactions were critical for maintaining pericyte function. Thus, our study reveals novel targets and insights into the pathogenesis of ED in patients with diabetes.

Single-cell RNA sequencing reveals critical modulators of extracellular matrix of penile cavernous cells in erectile dysfunction

Erectile dysfunction (ED) is a common and difficult to treat disease, and has a high incidence rate worldwide. As a marker of vascular disease, ED usually occurs in cardiovascular disease, 2-5 years prior to cardiovascular disease events. The extracellular matrix (ECM) network plays a crucial role in maintaining cardiac homeostasis, not only by providing structural support, but also by promoting force transmission, and by transducing key signals to intracardiac cells. However, the relationship between ECM and ED remains unclear. To help fill this gap, we profiled single-cell RNA-seq (scRNA-seq) to obtain transcriptome maps of 82,554 cavernous single cells from ED and non-ED samples. Cellular composition of cavernous tissues was explored by uniform manifold approximation and projection. Pseudo-time cell trajectory combined with gene enrichment analysis were performed to unveil the molecular pathways of cell fate determination. The relationship between cavernous cells and the ECM, and the changes in related genes were elucidated. The CellChat identified ligand-receptor pairs (e.g., PTN-SDC2, PTN-NCL, and MDK-SDC2) among the major cell types in the cavernous tissue microenvironment. Differential analysis revealed that the cell type-specific transcriptomic changes in ED are related to ECM and extracellular structure organization, external encapsulating structure organization, and regulation of vasculature development. Trajectory analysis predicted the underlying target genes to modulate ECM (e.g., COL3A1, MDK, MMP2, and POSTN). Together, this study highlights potential cell-cell interactions and the main regulatory factors of ECM, and reveals that genes may represent potential marker features of ED progression.