Pericyte-Derived Dickkopf2 Regenerates Damaged Penile Neurovasculature Through an Angiopoietin-1-Tie2 Pathway

Exogenous administration of heparin-binding epidermal growth factor-like growth factor improves erectile function in mice with bilateral cavernous nerve injury

Prostate cancer is the second most common malignancy and the sixth leading cause of cancer-related death in men worldwide. Radical prostatectomy (RP) is the standard treatment for localized prostate cancer, but the procedure often results in postoperative erectile dysfunction (ED). The poor efficacy of phosphodiesterase 5 inhibitors after surgery highlights the need to develop new therapies to enhance cavernous nerve regeneration and improve the erectile function of these patients. In the present study, we aimed to examine the potential of heparin-binding epidermal growth factor-like growth factor (HB-EGF) in preserving erectile function in cavernous nerve injury (CNI) mice. We found that HB-EGF expression was reduced significantly on the 1st day after CNI in penile tissue. Ex vivo and in vitro studies showed that HB-EGF promotes major pelvic ganglion neurite sprouting and neuro-2a (N2a) cell migration. In vivo studies showed that exogenous HB-EGF treatment significantly restored the erectile function of CNI mice to 86.9% of sham levels. Immunofluorescence staining showed that mural and neuronal cells were preserved by inducing cell proliferation and reducing apoptosis and reactive oxygen species production. Western blot analysis showed that HB-EGF upregulated protein kinase B and extracellular signal-regulated kinase activation and neurotrophic factor expression. Overall, HB-EGF is a major promising therapeutic agent for treating ED in postoperative RP.

Role of pericytes in regulating penile angiogenesis and nerve regeneration

ABSTRACT

Pericytes are multifunctional mural cells that surround the abluminal wall of endothelial cells and are associated with vascular development, vascular permeability, and angiogenesis. Additionally, pericytes demonstrate stem cell-like properties and contribute to neuroinflammatory processes. Pericytes have been extensively studied in the central nervous system. However, specific mechanisms underlying its involvement in various physiological and pathological conditions, especially in erectile dysfunction (ED), remain poorly understood. Advancements in in vitro and in vitro techniques, such as single-cell RNA sequencing, are expanding our understanding of pericytes. Recent studies have shown that pericyte dysfunction is considered an important factor in the pathogenesis of vascular and neurological ED. Therefore, this study aims to analyze the specific role of pericytes in ED, focusing on diabetic and neurogenic ED. This article provides a comprehensive review of research findings on PubMed from 2000 to 2023, concerning pericyte dysfunction in the process of ED, offering valuable insights, and suggesting directions for further research.

Heparin-binding epidermal growth factor-like growth factor improves erectile function in streptozotocin-induced diabetic mice

BACKGROUND

Heparin-binding epidermal growth factor-like growth factor (HB-EGF) serves as a pro-angiogenic factor; however, there is to our knowledge currently no reported research on the relationship between HB-EGF and diabetic erectile dysfunction (ED).

AIM

In this study we aimed to determine whether HB-EGF can improve the erectile function of streptozotocin-induced diabetic mice and to explore the related mechanisms.

METHODS

Eight-week-old male C57BL/6 mice were used for diabetes induction. Diabetes mellitus (DM) was induced by low-dose injections of streptozotocin (50 mg/kg) for 5 consecutive days. Eight weeks after streptozotocin injections, DM was determined by measuring blood glucose and body weight. Diabetic mice were treated with two intracavernous administrations of phosphate-buffered saline (20 μL) or various doses of HB-EGF (days -3 and 0; 1, 5, and 10 μg in 20 μL of phosphate-buffered saline). The angiogenesis effect of HB-EGF was confirmed by tube formation and migration assays in mouse cavernous endothelial cells and mouse cavernous pericytes under high-glucose conditions. Erectile function was measured by electrical stimulation of the cavernous nerve, as well as histological examination and Western blot analysis for mechanism assessment.

OUTCOMES

In vitro angiogenesis, cell proliferation, in vivo intracavernous pressure, neurovascular regeneration, cavernous permeability, and survival signaling were the outcomes measured.

RESULTS

Expression of HB-EGF was reduced under diabetic conditions. Exogenous HB-EGF induced angiogenesis in mouse cavernous endothelial cells and mouse cavernous pericytes under high-glucose conditions. Erectile function was decreased in the DM group, whereas administration of HB-EGF resulted in a significant improvement of erectile function (91% of the age-matched control group) in association with increased neurovascular content, including cavernous endothelial cells, pericytes, and neuronal cells. Histological and Western blot analyses revealed a significant increase in the permeability of the corpus cavernosum in DM mice, which was attenuated by HB-EGF treatment. The protein expression of phospho-Akt Ser473 and phosphorylated endothelial nitric oxide synthase Ser1177 increased after HB-EGF treatment.

CLINICAL IMPLICATIONS

The use of HB-EGF may be an effective strategy to treat ED associated with DM or other neurovascular diseases.

STRENGTHS AND LIMITATIONS

Similarly to other pro-angiogenic factors, HB-EGF has dual roles in vascular and neuronal development. Our study focused on broadly evaluating the role of HB-EGF in diabetic ED. In view of the properties of HB-EGF as an angiogenic factor, its dose concentration should be strictly controlled to avoid potential side effects.

CONCLUSION

In the diabetic ED mouse model in this study erectile function was improved by HB-EGF, which may provide new treatment strategies for patients with ED who do not respond to phosphodiesterase 5 Inhibitors.

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.

Regenerative therapies as a potential treatment of erectile dysfunction

Erectile dysfunction (ED) is the most common sexual dysfunction disease in adult males. ED can be caused by many factors, such as vascular disease, neuropathy, metabolic disturbances, psychosocial causes, and side effects of medications. Although current oral phosphodiesterase type 5 inhibitors can achieve a certain effect, they cause temporary dilatation of blood vessels with no curative treatment effects. Emerging targeted technologies, such as stem cell therapy, protein therapy, and low-intensity extracorporeal shock wave therapy (Li-ESWT), are being used to achieve more natural and long-lasting effects in treating ED. However, the development and application of these therapeutic methods are still in their infancy, and their pharmacological pathways and specific mechanisms have not been fully discovered. This article reviews the preclinical basic research progress of stem cells, proteins, and Li-ESWT therapy, as well as the current status of clinical application of Li-ESWT therapy.

Argonaute 2 Restores Erectile Function by Enhancing Angiogenesis and Reducing Reactive Oxygen Species Production in Streptozotocin (STZ)-Induced Type-1 Diabetic Mice

Severe vascular and nerve damage from diabetes is a leading cause of erectile dysfunction (ED) and poor response to oral phosphodiesterase 5 inhibitors. Argonaute 2 (Ago2), a catalytic engine in mammalian RNA interference, is involved in neurovascular regeneration under inflammatory conditions. In the present study, we report that Ago2 administration can effectively improve penile erection by enhancing cavernous endothelial cell angiogenesis and survival under diabetic conditions. We found that although Ago2 is highly expressed around blood vessels and nerves, it is significantly reduced in the penis tissue of diabetic mice. Exogenous administration of the Ago2 protein restored erectile function in diabetic mice by reducing reactive oxygen species production-signaling pathways (inducing eNOS Ser¹¹⁷⁷/NF-κB Ser⁵³⁶ signaling) and improving cavernous endothelial angiogenesis, migration, and cell survival. Our study provides new evidence that Ago2 mediation may be a promising therapeutic strategy and a new approach for diabetic ED treatment.

IGFBP5 antisense and short hairpin RNA (shRNA) constructs improve erectile function by inducing cavernosum angiogenesis in diabetic mice

BACKGROUND

The incidence of diabetic erectile dysfunction (ED) is rapidly increasing, and due to the severe angiopathy caused by diabetes, current drugs are ineffective at treating ED. Insulin-like growth factor-binding protein 5 (IGFBP5) promotes cell death and induces apoptosis in various cell types.

OBJECTIVES

To evaluate the effectiveness of IGFBP5 knockdown in improving erectile function in diabetic mice.

MATERIALS AND METHODS

Diabetes was induced by injecting streptozotocin (STZ) intraperitoneally into male 8-week-old C57BL/6 mice. Eight weeks after diabetes induction, mice were divided into four groups: a nondiabetic control group and three STZ-induced diabetic mice groups, which were administered intracavernous injections of phosphate buffered saline, scrambled control shRNA, or shRNA targeting mouse IGFBP5 (shIGFBP5) lentivirus particles. Two weeks later, we measured erectile function by electrically stimulating the bilateral cavernous nerve. To mimic diabetic angiopathy, primary cavernous endothelial cells (MCECs) from healthy mice were cultured and treated with glucose.

RESULTS

IGFBP5 expression in MCECs or cavernous tissues were significantly increased under diabetic conditions, and knockdown of IGFBP5 induced MCECs angiogenic activity under high-glucose conditions. STZ-induced diabetic mice had reduced erectile function, but shIGFBP5 treatment resulted in significant improvements (to 90% of the nondiabetic control group level). Furthermore, in diabetic mice, numbers of cavernous endothelial cells, pericytes, and neuronal cells were increased by shIGFBP5 treatment, which also increased eNOS Ser¹¹⁷⁷ phosphorylation, decreased permeability and apoptosis of cavernous endothelial cells. In addition, IGFBP5 was found to mediate the AKT, ERK, p38 signaling pathways.

DISCUSSION AND CONCLUSION

Knockdown of IGFBP5 improved erectile function in diabetic mice by promoting cell proliferation and reducing apoptosis and permeability. Local inhibition of IGFBP5 expression may provide a new treatment strategy for diabetic ED and other ischemic vascular or neurological diseases.

Dual Targeting of Angipoietin-1 and von Willebrand Factor by microRNA-671-5p Attenuates Liver Angiogenesis and Fibrosis

Angipoietin-1 (Angpt1) and von Willebrand factor (VWF) are two important angiogenic molecules that can drive pathologic angiogenesis and progression of liver fibrosis in our previous study. MicroRNAs (miRs) participate in a variety of physiological and pathological processes, including angiogenesis. However, the critical miRs targeting Angpt1 or VWF and potential molecular mechanism underlying liver fibrosis-associated angiogenesis is not clear yet. Human liver tissues were obtained from patients with different chronic liver diseases. Mouse models of liver fibrosis were induced by injection of CCl₄ or bile duct ligation (BDL) operation. MiR-671-5p was predicted to target Angpt1 and VWF from three databases (miRanda, RNA22v2, and miRwalk). MiR-671-5p expression was decreased in the fibrotic liver of human and mice, with a negative correlation with the levels of Angpt1, VWF, sphingosine kinase-1 (SphK1, the rate-limiting enzyme for sphingosine 1-phosphate [S1P] formation), transforming growth factor β1 (TGFβ1), hypoxia inducible factor (Hif)1α, Hif2α, and fibrosis markers. Importantly, miR-671-5p expression was down-regulated in fluorescence-activated cell sorted liver sinusoidal endothelial cells and hepatic stellate cells (HSCs) in CCl₄ mice compared with control mice. In vitro miR-671-5p expression was also decreased in S1P-stimulated HSCs and TGFβ1-activated liver sinusoidal endothelial cells, negatively correlated with Angpt1 and VWF expression. MiR-671-5p directly targeted Angpt1 and VWF by luciferase reporter assays. In vivo administration of miR-671-5p agomir decreased the messenger RNA and protein levels of Anpgt1 and VWF, and attenuated CCl₄ -induced or BDL-induced liver angiogenesis and fibrosis. Conclusion: We identify the negative regulation of miR-671-5p on Angpt1 and VWF and liver fibrosis-associated angiogenesis, which may provide promising targets for the prevention and treatment of liver disease.

Pericyte‑derived extracellular vesicles‑mimetic nanovesicles improves peripheral nerve regeneration in mouse models of sciatic nerve transection

Pericyte‑derived extracellular vesicle‑mimetic nanovesicles (PC‑NVs) play an important role in the improvement of erectile function after cavernous nerve injury. However, the impact of PC‑NVs on the peripheral nervous system (PNS), such as the sciatic nerve, is unclear. In this study, PC‑NVs were isolated from mouse cavernous pericytes (MCPs). A sciatic nerve transection (SNT) model was established using 8‑week‑old C57BL/6J mice. The sciatic nerve was harvested 5 and 14 days for immunofluorescence and western blot studies. Function studies were evaluated by performing the rotarod test and walking track analysis. The results demonstrated that PC‑NVs could stimulate endothelial cells, increase neuronal cell content, and increase macrophage and Schwann cell presence at the proximal stump rather than the distal stump in the SNT model, thereby improving angiogenesis and nerve regeneration in the early stage of sciatic nerve regeneration. In addition, PC‑NVs also increased the expression of neurotrophic factors (brain‑derived nerve growth factor, neurotrophin‑3 and nerve growth factor) and the activity of the cell survival signaling pathway (PI3K/Akt signaling), and reduced the activity of the JNK signaling pathway. Additionally, after 8 weeks of local application of PC‑NVs in SNT model mice, their motor and sensory functions were significantly improved, as assessed by performing the rotarod test and walking track analysis. In conclusion, the present study showed that the significant improvement of neurovascular regeneration in mice following treatment with PC‑NVs may provide a favorable strategy for promoting motor and sensory regeneration and functional recovery of the PNS.

Heat Shock Protein 70 in Penile Neurovascular Regeneration Requires Cystathionine Gamma-Lyase

Purpose

Diabetes mellitus, one of the major causes of erectile dysfunction, leads to a poor response to phosphodiesterase-5 inhibitors. Heat shock protein 70 (Hsp70), a ubiquitous molecular chaperone, is known to play a role in cell survival and neuroprotection. Here, we aimed to assess whether and how Hsp70 improves erectile function in diabetic mice.

Materials and Methods

Eight-week-old male C57BL/6 mice and Hsp70-Tg mice were used in this study. We injected Hsp70 protein into the penis of streptozotocin (STZ)-induced diabetic mice. Detailed mechanisms were evaluated in WT or Hsp70-Tg mice under normal and diabetic conditions. Primary MCECs, and MPG and DRG tissues were cultivated under normal-glucose and high-glucose conditions.

Results

Using Hsp70-Tg mice or Hsp70 protein administration, we demonstrate that elevated levels of Hsp70 restores erectile function in diabetic mice. We found that cystathionine gamma-lyase (Cse) is a novel target of Hsp70 in this process, showing that Hsp70-Cse acts through the SDF1/HO-1/PI3K/Akt/eNOS/NF-κB p65 pathway to exert its neurovascular regeneration-promoting effects. Coimmunoprecipitation and pull-down assays using mouse cavernous endothelial cells treated with Hsp70 demonstrated physical interactions between Hsp70 and Cse with a dissociation constant of 1.8 nmol/L.

Conclusions

Our findings provide novel and solid evidence that Hsp70 acts through a Cse-dependent mechanism to mediate neurovascular regeneration and restoration of erectile function under diabetic conditions.

Role of pericytes in diabetic angiogenesis

ABSTRACT

In the context of diabetes mellitus, various pathological changes cause tissue ischemia and hypoxia, which can lead to the compensatory formation of neovascularization. However, disorders of the internal environment and dysfunctions of various cells contribute to the dysfunction of neovascularization. Although the problems of tissue ischemia and hypoxia have been partially solved, neovascularization also causes many negative effects. In the process of small blood vessel renewal, pericytes are extremely important for maintaining the normal growth and maturation of neovascularization. Previously, our understanding of pericytes was very limited, and the function of pericytes was not yet clear. Recently, multiple new functions of pericytes have been identified, affecting various processes in angiogenesis and relating to various diseases. Therefore, the importance of pericytes has gradually become apparent. This article presents the latest research progress on the role of pericytes in diabetic angiogenesis, characterizes pericytes, summarizes various potential therapeutic targets, and highlights research directions for the future treatment of various diabetes-related diseases.

RNA-sequencing profiling analysis of pericyte-derived extracellular vesicle-mimetic nanovesicles-regulated genes in primary cultured fibroblasts from normal and Peyronie's disease penile tunica albuginea

BACKGROUND

Peyronie's disease (PD) is a severe fibrotic disease of the tunica albuginea that causes penis curvature and leads to penile pain, deformity, and erectile dysfunction. The role of pericytes in the pathogenesis of fibrosis has recently been determined. Extracellular vesicle (EV)-mimetic nanovesicles (NVs) have attracted attention regarding intercellular communication between cells in the field of fibrosis. However, the global gene expression of pericyte-derived EV-mimetic NVs (PC-NVs) in regulating fibrosis remains unknown. Here, we used RNA-sequencing technology to investigate the potential target genes regulated by PC-NVs in primary fibroblasts derived from human PD plaque.

METHODS

Human primary fibroblasts derived from normal and PD patients was cultured and treated with cavernosum pericytes isolated extracellular vesicle (EV)-mimetic nanovesicles (NVs). A global gene expression RNA-sequencing assay was performed on normal fibroblasts, PD fibroblasts, and PD fibroblasts treated with PC-NVs. Reverse transcription polymerase chain reaction (RT-PCR) was used for sequencing data validation.

RESULTS

A total of 4135 genes showed significantly differential expression in the normal fibroblasts, PD fibroblasts, and PD fibroblasts treated with PC-NVs. However, only 91 contra-regulated genes were detected among the three libraries. Furthermore, 20 contra-regulated genes were selected and 11 showed consistent changes in the RNA-sequencing assay, which were validated by RT-PCR.

CONCLUSION

The gene expression profiling results suggested that these validated genes may be good targets for understanding potential mechanisms and conducting molecular studies into PD.

Lung Pericytes in Pulmonary Vascular Physiology and Pathophysiology

Pericytes are mesenchymal-derived mural cells localized within the basement membrane of pulmonary and systemic capillaries. Besides structural support, pericytes control vascular tone, produce extracellular matrix components, and cytokines responsible for promoting vascular homeostasis and angiogenesis. However, pericytes can also contribute to vascular pathology through the production of pro-inflammatory and pro-fibrotic cytokines, differentiation into myofibroblast-like cells, destruction of the extracellular matrix, and dissociation from the vessel wall. In the lung, pericytes are responsible for maintaining the integrity of the alveolar-capillary membrane and coordinating vascular repair in response to injury. Loss of pericyte communication with alveolar capillaries and a switch to a pro-inflammatory/pro-fibrotic phenotype are common features of lung disorders associated with vascular remodeling, inflammation, and fibrosis. In this article, we will address how to differentiate pericytes from other cells, discuss the molecular mechanisms that regulate the interactions of pericytes and endothelial cells in the pulmonary circulation, and the experimental tools currently used to study pericyte biology both in vivo and in vitro. We will also discuss evidence that links pericytes to the pathogenesis of clinically relevant lung disorders such as pulmonary hypertension, idiopathic lung fibrosis, sepsis, and SARS-COVID. Future studies dissecting the complex interactions of pericytes with other pulmonary cell populations will likely reveal critical insights into the origin of pulmonary diseases and offer opportunities to develop novel therapeutics to treat patients afflicted with these devastating disorders. © 2021 American Physiological Society. Compr Physiol 11:2227-2247, 2021.

Vasohibin-1 rescues erectile function through up-regulation of angiogenic factors in the diabetic mice

Neovascularization of the erectile tissue emerges as a beneficial curative approach to treat erectile dysfunction (ED). Here we for the first time report the unexpected role of vasohibin-1 (VASH1), mainly known as an anti-angiogenic factor, in restoring erectile function in diabetic mice. A diabetic patient has lower cavernous VASH1 expression than in the potent man. VASH1 was mainly expressed in endothelial cells. There were significant decreases in cavernous endothelial cell and pericyte contents in VASH1 knockout mice compared with those in wild-type mice, which resulted in impairments in erectile function. Intracavernous injection of VASH1 protein successfully restored erectile function in the diabetic mice (~ 90% of control values). VASH1 protein reinstated endothelial cells, pericytes, and endothelial cell–cell junction proteins and induced phosphorylation of eNOS (Ser1177) in the diabetic mice. The induction of angiogenic factors, such as angiopoietin-1 and vascular endothelial growth factor, is responsible for cavernous angiogenesis and the restoration of erectile function mediated by VASH1. Altogether, these findings suggest that VASH1 is proangiogenic in diabetic penis and is a new potential target for diabetic ED.

A Method to Isolate Pericytes From the Mouse Urinary Bladder for the Study of Diabetic Bladder Dysfunction

Purpose

Pericytes surround the endothelial cells in microvessels and play a distinct role in controlling vascular permeability and maturation. The loss of pericyte function is known to be associated with diabetic retinopathy and erectile dysfunction. This study aimed to establish a technique for the isolation of pericytes from the mouse urinary bladder and an in vitro model that mimics in vivo diabetic bladder dysfunction.

Methods

To avoid contamination with epithelial cells, the urothelial layer was meticulously removed from the underlying submucosa and detrusor muscle layer. The tissues were cut into multiple pieces, and the fragmented tissues were settled by gravity into collagen I-coated culture plates. The cells were cultured under normal-glucose (5 mmol/L) or high-glucose (30 mmol/L) conditions, and tube formation, cell proliferation, and TUNEL assays were performed. We also performed hydroethidine staining to measure superoxide anion production.

Results

We successfully isolated high-purity pericytes from the mouse urinary bladder. The cells were positively stained for platelet-derived growth factor receptor-β and NG2 and negatively stained for smooth muscle cell markers (desmin and myosin) and an endothelial cell marker (CD31). The number of tubes formed and the number of proliferating cells were significantly lower when the pericytes were exposed to high-glucose conditions compared with normal-glucose conditions. In addition, there were significant increases in superoxide anion production and the number of apoptotic cells when the pericytes were cultured under high-glucose conditions.

Conclusions

To the best of our knowledge, this is the first study to isolate and culture pericytes from the mouse urinary bladder. Our model would be a useful tool for screening the efficacy of therapeutic candidates targeting pericyte function in diabetic bladder dysfunction and exploring the functional role of specific targets at the cellular level.

Neutralizing antibody to proNGF rescues erectile function by regulating the expression of neurotrophic and angiogenic factors in a mouse model of cavernous nerve injury

BACKGROUND

Radical prostatectomy induces some degree of cavernous nerve injury (CNI) and causes denervation-induced pathologic changes in cavernous vasculature, regardless of the advances in surgical techniques and robotic procedures. The precursor for nerve growth factor (proNGF) is known to be involved in neuronal cell apoptosis and microvascular dysfunction through its receptor p75NTR .

OBJECTIVES

To determine the expression of proNGF/p75NTR and the efficacy of proNGF neutralizing antibody (anti-proNGF-Ab) in a mouse model of ED induced by CNI.

MATERIALS AND METHODS

Age-matched 12-week-old C57BL/6 mice were distributed into three groups: sham group and bilateral CNI group treated with intracavernous injections of PBS (20 μL) or of anti-proNGF-Ab (20 µg in 20 μL of PBS) on days -3 and 0. Two weeks after treatment, erectile function was measured by electrical stimulation of cavernous nerve. Penis tissues from a separate group of animals were harvested for further analysis. We also determined the efficacy of anti-proNGF-Ab on neural preservation in major pelvic ganglion (MPG) ex vivo.

RESULTS

We observed increased penile expression of proNGF and p75NTR after CNI. Intracavernous administration of anti-proNGF-Ab increased nNOS and neurofilament expression probably by enhancing the production of neurotrophic factors, such as neurotrophin-3, NGF, and brain-derived neurotrophic factor. Anti-proNGF-Ab preserved the integrity of cavernous sinusoids, such as pericytes, endothelial cells, and endothelial cell-to-cell junctions, possibly by controlling angiogenic factors (angiopoietin-1, angiopoietin-2, and vascular endothelial growth factor) and induced endogenous eNOS phosphorylation in CNI mice. And finally, treatment with anti-proNGF-Ab rescued erectile function in CNI mice. Anti-proNGF-Ab also enhanced neurite sprouting from MPG exposed to lipopolysaccharide.

DISCUSSION AND CONCLUSION

The preservation of damaged cavernous neurovasculature through inhibition of the proNGF/p75NTR pathway may be a novel strategy to treat radical prostatectomy-induced erectile dysfunction.

Gene expression profiling of mouse cavernous endothelial cells for diagnostic targets in diabetes-induced erectile dysfunction

PURPOSE

To investigate potential target genes associated with the diabetic condition in mouse cavernous endothelial cells (MCECs) for the treatment of diabetes-induced erectile dysfunction (ED).

MATERIALS AND METHODS

Mouse cavernous tissue was embedded into Matrigel, and sprouted cells were subcultivated for other studies. To mimic diabetic conditions, MCECs were exposed to normal-glucose (NG, 5 mmoL) or high-glucose (HG, 30 mmoL) conditions for 72 hours. An RNA-sequencing assay was performed to evaluate gene expression profiling, and RT-PCR was used to validate the sequencing data.

RESULTS

We isolated MCECs exposed to the two glucose conditions. MCECs showed well-organized tubes and dynamic migration in the NG condition, whereas tube formation and migration were significantly decreased in the HG condition. RNA-sequencing analysis showed that MCECs had different gene profiles in the NG and HG conditions. Among the significantly changed genes, which we classified into 14 major gene categories, we identified that aging-related (9.22%) and angiogenesis-related (9.06%) genes were changed the most. Thirteen genes from the two gene categories showed consistent changes on the RNA-sequencing assay, and these findings were validated by RT-PCR.

CONCLUSIONS

Our gene expression profiling studies showed that Cyp1a1, Gclm, Igfbp5, Nqo1, Il6, Cxcl5, Olr1, Ctgf, Hbegf, Serpine1, Cyr61, Angptl4, and Loxl2 may play a critical role in diabetes-induced ED through aging and angiogenesis signaling. Additional research is necessary to help us understand the potential mechanisms by which these genes influence diabetes-induced ED.

Transcriptional profiling of mouse cavernous pericytes under high-glucose conditions: Implications for diabetic angiopathy

Purpose

Penile erection requires integrative interactions between vascular endothelial cells, pericytes, smooth muscle cells, and autonomic nerves. Furthermore, the importance of the role played by pericytes in the pathogenesis of angiopathy has only recently been appreciated. However, global gene expression in pericytes in diabetes mellitus-induced erectile dysfunction (DMED) remains unclear. We aimed to identify potential target genes related to DMED in mouse cavernous pericytes (MCPs).

Materials and Methods

Mouse cavernous tissue was allowed to settle under gravity in collagen I-coated dishes, and sprouted cells were subcultivated for experiments. To imitate diabetic conditions, MCPs were treated with normal-glucose (NG, 5 mM) or high-glucose (HG, 30 mM) media for 3 days. Microarray technology was used to evaluate gene expression profiles, and RT-PCR was used to validate sequencing data. Histological examinations and Western blot were used to validate final selected target genes related to DMED.

Results

Decreased tube formation and increased apoptosis were detected in MCPs exposed to the HG condition. As shown by microarray analysis, the gene expression profiles of MCPs exposed to the NG or HG condition differed. A total of 2,523 genes with significantly altered expression were classified into 15 major gene categories. After further screening based on gene expression and RT-PCR and histologic results, we found that Hebp1 gene expression was significantly diminished under the HG condition and in DM mice.

Conclusions

This gene profiling study provides new potential targets responsible for diabetes in MCPs. Validation studies suggest that Hebp1 may be a suitable biomarker for DMED.

Pericyte-Derived Extracellular Vesicle-Mimetic Nanovesicles Restore Erectile Function by Enhancing Neurovascular Regeneration in a Mouse Model of Cavernous Nerve Injury

BACKGROUND

Extracellular vesicle (EV)-mimetic nanovesicles (NVs) from embryonic stem cells have been observed to stimulate neurovascular regeneration in the streptozotocin-induced diabetic mouse. Pericytes play important roles in maintaining penile erection, yet no previous studies have explored the effects of pericyte-derived NVs (PC-NVs) in neurovascular regeneration in the context of erectile dysfunction.

AIM

To investigate the potential effect of PC-NVs in neurovascular regeneration.

METHODS

PC-NVs were isolated from mouse cavernous pericytes, and neurovascular regeneration was evaluated in an in vitro study. Twelve-week-old C57BL/6J mice were used to prepare cavernous nerve injury model. Erectile function evaluation, histologic examination of the penis, and Western blots were assessed 2 weeks after model creation and PC-NVs treatment.

OUTCOMES

The main outcomes of this study are PC-NVs characterization, intracavernous pressure, neurovascular regeneration in the penis, and in vitro functional evaluation.

RESULTS

The PC-NVs were extracted and characterized by cryotransmission electron microscopy and EV-positive (Alix, TSG101, CD81) and EV-negative (GM130) markers. In the in vivo studies, PC-NVs successfully improved erectile function in cavernous nerve injury mice (∼82% of control values). Immunofluorescence staining showed significant increases in pericytes, endothelial cell, and neuronal contents. In the in vitro studies, PC-NVs significantly increased mouse cavernous endothelial cells tube formation, Schwann cell migration, and dorsal root ganglion and major pelvic ganglion neurite sprouting. Finally, Western blot analysis revealed that PC-NVs upregulated cell survival signaling (Akt and eNOS) and induced the expression of neurotrophic factors (brain-derived neurotrophic factor, neurotrophin-3, and nerve growth factor).

CLINICAL IMPLICATIONS

PC-NVs may be used as a strategy to treat erectile dysfunction after radical prostatectomy or in men with neurovascular diseases.

STRENGTHS & LIMITATIONS

We evaluated the effect of PC-NVs in vitro and in a mouse nerve injury model, cavernous nerve injury. Additional studies are necessary to determine the detailed mechanisms of neurovascular improvement. Further study is needed to test whether PC-NVs are also effective when given weeks or months after nerve injury.

CONCLUSION

PC-NVs significantly improved erectile function by enhancing neurovascular regeneration. Local treatment with PC-NVs may represent a promising therapeutic strategy for the treatment of neurovascular diseases. Yin GN, Park S-H, Ock J, et al. Pericyte-Derived Extracellular Vesicle-Mimetic Nanovesicles Restore Erectile Function by Enhancing Neurovascular Regeneration in a Mouse Model of Cavernous Nerve Injury. J Sex Med 2020;17:2118-2128.

Embryonic stem cell-derived extracellular vesicle-mimetic nanovesicles rescue erectile function by enhancing penile neurovascular regeneration in the streptozotocin-induced diabetic mouse

Extracellular vesicles (EVs) have attracted particular interest in various fields of biology and medicine. However, one of the major hurdles in the clinical application of EV-based therapy is their low production yield. We recently developed cell-derived EV-mimetic nanovesicles (NVs) by extruding cells serially through filters with diminishing pore sizes (10, 5, and 1 μm). Here, we demonstrate in diabetic mice that embryonic stem cell (ESC)-derived EV-mimetic NVs (ESC-NVs) completely restore erectile function (~96% of control values) through enhanced penile angiogenesis and neural regeneration in vivo, whereas ESC partially restores erectile function (~77% of control values). ESC-NVs promoted tube formation in primary cultured mouse cavernous endothelial cells and pericytes under high-glucose condition in vitro; and accelerated microvascular and neurite sprouting from aortic ring and major pelvic ganglion under high-glucose condition ex vivo, respectively. ESC-NVs enhanced the expression of angiogenic and neurotrophic factors (hepatocyte growth factor, angiopoietin-1, nerve growth factor, and neurotrophin-3), and activated cell survival and proliferative factors (Akt and ERK). Therefore, it will be a better strategy to use ESC-NVs than ESCs in patients with erectile dysfunction refractory to pharmacotherapy, although it remains to be solved for future clinical application of ESC.

Deletion of narfl leads to increased oxidative stress mediated abnormal angiogenesis and digestive organ defects in zebrafish

Nuclear prelamin A recognition factor-like (NARFL) is a human protein that participates in cytosolic iron-sulfur (Fe-S) protein biogenesis and cellular defense against oxidative stress. Previous studies of Narfl knockout mice did not reveal well the regulatory mechanisms of embryonic development mediated by Narfl because the homozygous mice die in utero. Here, we investigated the function of narfl in an established zebrafish knockout model by taking advantage of zebrafish external fertilization and ease of embryonic development examination. Our experiments showed that narfl deletion resulted in larvae lethality, subintestinal vessel (SIV) malformation and digestive organ defects in the early stages of embryonic development. Biochemical analyses and western blot revealed increased oxidative stress and upregulated hypoxia-inducible factor-1α (HIF-1α) expression in narfl^-/- fish. The use of HIF-1α inhibitor 2-methoxyestradiol (2ME2) for the treatment of mutants partially rescued the SIV sprouting. These results suggest that narfl deletion causes increased oxidative stress and subintestinal vessel malformation, which further influence the development of digestive organs and might contribute to the lethality of the narfl knockout fish.

Glomerular endothelial cells versus podocytes as the cellular target in diabetic nephropathy

It usually takes several years (in some cases, decades) for predisposed individuals to move from the onset of type 1 or type 2 diabetes to the development of microalbuminuria, the first sign of diabetic nephropathy. This long, complication-free, period represents the best possible moment to start a successful preventive strategy (primary prevention) aimed to avoid or at least to postpone the increase of albumin excretion rate. Prevention is based on understanding and counteracting the initial mechanisms leading to the development of the disease and unfortunately, in case of diabetic nephropathy, most of them remain unclear. Little is also known about which, among endothelial cells and podocytes, represent the first glomerular target of the complication. Selective damage of the endothelium or of the podocyte results, as a common consequence, in an increase of albumin excretion rate. Albuminuria by itself cannot therefore be of help to solve the case. Endothelium and podocytes are involved in a continuous cross-talk and by studying the impact of diabetes on this "communication" process it should be possible to obtain some information regarding the weak component of the glomerular filter. Finally, the careful investigation of the mechanisms leading to the development podocyturia, a recently identified glomerular dysfunction associated to the pathogenesis of diabetic nephropathy, could contribute to shed some more light on the very early stages of this complication.

Exercise training causes a partial improvement through increasing testosterone and eNOS for erectile function in middle-aged rats

PURPOSE

Aging changes the balance of sex hormones and causes endothelial dysfunction in the penis, both of which are important determinants of erectile dysfunction (ED). The purpose of this study was to evaluate whether exercise training could protect against erectile dysfunction by increasing serum testosterone and penile eNOS levels in aging rats.

METHODS

A total of 14 young (2-month-old) and 14 middle-aged (18-month-old) Sprague Dawley rats were randomly assigned to either untrained control (young control, [YC], middle-aged control, [MC]) or endurance exercise-trained (young exercise, [YE], middle-aged exercise, [ME]) groups with seven rats per group. The exercise groups trained with treadmill running for 6 weeks. Body composition parameters (body weight, heart mass, liver mass, and testicular mass), serum sex hormone levels (testosterone, luteinizing hormone, follicle-stimulating hormone, and prolactin), endothelial function-related parameters in the penis (endothelial nitric oxide synthase [eNOS], CD31, alpha smooth muscle actin [α-SMA]), and maximal intracavernous pressure measure (ICP) and total ICP were analyzed in middle-aged rats.

RESULTS

The middle-aged groups showed increased body weight, as compared with the young groups, but exercise training attenuated the aging-induced increase in body weight. The middle-aged groups had lower testicular mass compared with the young groups, but exercise training attenuated aging-induced decreases in testicular mass. Exercise training increased serum testosterone levels in both the young and middle-aged groups. However, there were no changes in the levels of luteinizing hormone, follicle-stimulating hormone, and prolactin among the groups. MC group showed decreased protein levels of p-eNOS, as compared with the YC group. However, exercise training protected against aging-induced decrease in eNOS and p-eNOS protein levels in the penis. Interestingly, exercise training also increased protein levels of α-SMA and maximal ICP in the middle-aged group.

CONCLUSIONS

Exercise training has beneficial effects on erectile function in aged rats through increased testosterone production from the testis and strengthening of the cavernous endothelium with activation of eNOS. Therefore, exercise training may be a therapeutic modality for improving erectile dysfunction associated with aging.