Efficient gene expression system using the RTP801 promoter in the corpus cavernosum of high-cholesterol diet-induced erectile dysfunction rats for gene therapy

Molecular Mechanism of Crataegi Folium and Alisma Rhizoma in the Treatment of Dyslipidemia Based on Network Pharmacology and Molecular Docking

Background

Dyslipidemia has become a critical global issue for public health, with elevating prevalence and morbidity closely related to many cardiovascular diseases (CVD) with high incidence rates. Crataegi Folium (known as Shanzhaye in China, SZ, the leaves of Crataegus pinnatifida Bge. var. major N.E. Br. or Crataegus pinnatifida Bge) and Alisma rhizoma (known as Zexie in China, ZX, the dried tuber of Alisma orientale (Sam.) Juzep or Alisma plantago-aquatica Linn), a classic combination of herbs, have been widely used to treat dyslipidemia. However, the therapeutic mechanism of this pair still remains unclear. Hence, this study aimed to elucidate the molecular mechanism of the Shanzhaye-Zexie herb pair (SZHP) in the treatment of dyslipidemia with the use of a network pharmacology analysis approach.

Methods

Active compounds, targets of the SZHP, and targets for dyslipidemia were screened based on the public database. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment were performed on the database for annotation, visualization, and integrated discovery (DAVID 6.8). The compound-target-disease-pathway network was visualized using the Cytoscape software, and SYBYL was used for molecular docking.

Results

Twelve active compounds in the SZHP were screened out, which were closely connected to 186 dyslipidemia-related targets. The network analysis revealed that sitosterol, stigmasterol, isorhamnetin, kaempferol, and quercetin might be candidate agents and CCND1, CASP3, HIF1A, and ESR1 genes were potential drug targets. GO analysis revealed 856 biological processes (BP), 139 molecular functions (MF), and 89 cellular components (CC). The KEGG pathway enrichment analysis indicated that the lipid level and atherosclerosis might influence the treatment of dyslipidemia. Molecular docking showed that quercetin bound well to CCND1, HIF1A, MYC, AKT1, and EGFR genes. These findings were in accord with the prediction obtained through the network pharmacology approach.

Conclusions

This study revealed the primary pharmacological effects and relevant mechanisms of the SZHP in treating dyslipidemia. Our findings may facilitate the development of the SZHP or its active compounds as an alternative therapy for dyslipidemia. Still, more pharmacological experiments are needed for verification.

Effect of simvastatin on rat supraspinatus tendon mechanical and histological properties in a diet-induced hypercholesterolemia model

Hypercholesterolemia is a common condition and is a risk factor for tendon rupture, specifically in the supraspinatus tendon. In the clinic, statins are commonly prescribed to lower cholesterol, but little information is available examining the effect of statin treatment on the musculoskeletal system. Therefore, the objective of this study was to determine the biomechanical and histological effects of statin treatment in a diet-induced hypercholesterolemia model. We hypothesized that hypercholesterolemic rats treated with statins would have improved tendon biomechanical and histological properties compared to hypercholesterolemic rats not receiving daily statin treatment. Thirty adult male Sprague-Dawley rats ate either high-cholesterol (HC) diet (n = 20) or normal chow (CTL, n = 10). After 6 months, a subset of HC rats began daily oral simvastatin dosing (HC+S) at 20 mg/kg. All rats were sacrificed after a total of 9 months (3 months of statin treatment) and evaluated for histology and mechanics. For mechanics, at the insertion region, HC+S group had increased tendon cross-sectional area decreased and modulus. No differences were noted in mechanical properties at the midsubstance. For histology, no differences were noted in the insertion region. In the midsubstance region, HC+S group had more spindle shaped cells. Our results suggest that 3 months of simvastatin treatment in a diet-induced hypercholesterolemia rat model alters some tendon mechanical and histological properties, although a strong conclusion in support of improved parameters cannot be drawn. Therefore, we conclude that simvastatin treatment does not negatively affect tendon properties. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2009-2015, 2016.

Rat rotator cuff tendon-to-bone healing properties are adversely affected by hypercholesterolemia

BACKGROUND

Rotator cuff tendon tears represent a major component of reported orthopaedic injuries. In addition, more than one quarter of U.S. adults either currently have high cholesterol levels or have reduced their previously high cholesterol levels through the use of pharmaceuticals. Our clinical data have already linked hypercholesterolemia to full-thickness rotator cuff tears, and experimental data from our laboratory have shown effects on native tendon properties in multiple species. The objective of this study was to evaluate healing of supraspinatus tendons in our rat rotator cuff injury model. We hypothesized that tendon healing would be inferior in rats receiving a high-cholesterol diet for 6 months compared with those receiving standard chow.

METHODS

All animals were subjected to a unilateral supraspinatus detachment and repair surgery, with contralateral limbs serving as within-animal comparative data. Animals continued their respective diet courses, and their supraspinatus tendons were biomechanically or histologically evaluated at 2, 4, and 8 weeks postoperatively.

RESULTS

Biomechanical testing revealed a significant reduction in normalized stiffness in hypercholesterolemic rats compared with controls at 4 weeks after injury, whereas histologic analyses showed no significant differences in collagen organization, cellularity, or cell shape between groups.

CONCLUSION

On the basis of our findings, hypercholesterolemia may have a detrimental biomechanical effect on tendon healing in our rat rotator cuff injury and repair model.

LEVEL OF EVIDENCE

Basic science study, animal model.

Hypercholesterolemia increases supraspinatus tendon stiffness and elastic modulus across multiple species

BACKGROUND

More than one-quarter of Americans have hypercholesterolemia and/or are being treated with cholesterol-lowering medications. Given the systemic nature of hypercholesterolemia and remaining questions regarding its effect on tendons at a local level, we sought to assess the utility of small versus large animal model systems for translational studies by exploring the effect of hypercholesterolemia on supraspinatus tendon elastic mechanical properties in mice, rats, and monkeys. We hypothesized that stiffness and elastic modulus would be increased in tendons across species due to hypercholesterolemia.

MATERIALS AND METHODS

Supraspinatus tendons from normal (control) and high-cholesterol (HC) mice, rats, and monkeys were used in this study. After dissection, tendons were geometrically measured and tensile tested with tissue strain measured optically.

RESULTS

Overall, HC animals had significantly altered plasma lipid profiles. Biomechanical testing showed a significant increase in stiffness compared with control in HC mice and rats, as well as a nonsignificant trend for HC monkeys. Elastic modulus was also significantly increased in HC mice and monkeys, with HC rats showing a trend.

CONCLUSIONS

The consistency of our findings across species and between small and large animals, combined with the fact that the aged mice were exposed to lifelong hypercholesterolemia (compared with rats and nonhuman primates, which were fed HC diets), suggests that these increased properties may be inherent to the effect of hypercholesterolemia on supraspinatus tendon rather than due to an effect of cumulative exposure time to the effects of HC. Further investigation is needed to confirm this concept.

Therapeutic angiogenesis as a potential future treatment strategy for erectile dysfunction

The cavernous endothelium plays a crucial role in regulating the tone of the underlying smooth muscle and physiologic penile erection. Recently, the link between erectile dysfunction (ED) and cardiovascular disease was unveiled, and the main etiology of ED was found to be vasculogenic. Although oral phosphodiesterase-5 inhibitors are generally effective for men with ED, such therapies do not cure underlying vasculopathy in the corpus cavernosum tissue. This review addresses current preclinical protein, gene, and cell or stem cell therapies for enhancing cavernous endothelial regeneration and restoring erectile function.

Effect of hypoxia-inducible VEGF gene expression on revascularization and graft function in mouse islet transplantation

For gene transfer strategies to improve islet engraftment, vascular endothelial growth factor (VEGF) expression should be regulated in a way that matches the transient nature of revascularization with simultaneously avoiding undesirable effects of overexpression. The aim of this study was to investigate the effects of hypoxia-inducible VEGF gene transfer using the RTP801 promoter on islet grafts. We implanted pSV-hVEGF transfected, pRTP801-hVEGF transfected or nontransfected mouse islets under the kidney capsule of streptozotocin-induced diabetic syngeneic mice. Human VEGF immunostaining of day 3 grafts revealed that the pRTP801-hVEGF transfected group had higher hVEGF expression compared with the pSV-hVEGF transfected group. BS-1 staining of day 3 grafts from the pRTP801-hVEGF transfected group showed the highest vascular density, which was comparable with day 6 grafts from the nontransfected group. In 360 islet equivalent (IEQ)-transplantation which reverted hyperglycemia in all mice, the area under the curve of glucose levels during intraperitoneal glucose tolerance test 7 weeks post-transplant was lower in mice transplanted with pRTP801-hVEGF transfected grafts compared with mice transplanted with nontransfected grafts. In 220 IEQ-transplantations, diabetic mice transplanted with pRTP801-hVEGF islets became normoglycemic more rapidly compared with mice transplanted with pSV-hVEGF or nontransfected islets, and diabetes reversal rate after 50 days was 90%, 68%, and 50%, respectively. In conclusion, our results indicate that regulated overexpression of hVEGF in a hypoxia-inducible manner enhances islet vascular engraftment and preserves islet function overtime in transplants.

Hyperlipidemia does not prevent the cardioprotection by postconditioning against myocardial ischemia/reperfusion injury and the involvement of hypoxia inducible factor-1alpha upregulation

Hyperlipidemia is regarded as an independent risk factor in the development of ischemic heart disease, and it can increase the myocardial susceptibility to ischemia/reperfusion (I/R) injury. Ischemic postconditioning (Postcon) has been demonstrated to attenuate the myocardial injury induced by I/R in normal conditions. But the effect of ischemic Postcon on hyperlipidemic animals is unknown. Hypoxia inducible factor-1 (HIF-1) has been demonstrated to play a central role in the cardioprotection by preconditioning, which is one of the protective strategies except for Postcon. The aim of this study was to determine whether Postcon could reduce myocardial injury in hyperlipidemic animals and to assess whether HIF-1 was involved in Postcon mechanisms. Male Wistar rats underwent the left anterior descending coronary occlusion for 30 min followed by 180 min of reperfusion with or without Postcon after fed with high fat diet or normal diet for 8 weeks. The detrimental indices induced by the I/R insult included infarct size, plasma creatine kinase activity and caspase-3 activity. Results showed that hyperlipidemia remarkably enhanced the myocardial injury induced by I/R, while Postcon significantly decreased the myocardial injury in both normolipidemic and hyperlipidemic rats. Moreover, both hyperlipidemia and I/R promoted the HIF-1alpha expression. Most importantly, we have for the first time demonstrated that Postcon further induced a significant increase in HIF-1alpha protein level not only in normolipidemic but also in hyperlipidemic conditions. Thus, Postcon reduces the myocardial injury induced by I/R in normal and hyperlipidemic animals, and HIF-1alpha upregulation may involve in the Postcon-mediated cardioprotective mechanisms.

Hypoxia-specific gene expression for ischemic disease gene therapy

Gene therapy for ischemic diseases has been developed with various growth factors and anti-apoptotic genes. However, non-specific expression of therapeutic genes may induce deleterious side effects such as tumor formation. Hypoxia-specific regulatory systems can be used to regulate transgene expression in hypoxic tissues, in which gene expression is induced in ischemic tissues, but reduced in normal tissues by transcriptional, translational or post-translational regulation. Since hypoxia-inducible factor 1 (HIF-1) activates transcription of genes in hypoxic tissues, it can play an important role in the prevention of myocardial and cerebral ischemia. Hypoxia-specific promoters including HIF-1 binding sites have been used for transcriptional regulation of therapeutic genes. Also, hypoxia-specific untranslated regions (UTRs) and oxygen dependent degradation (ODD) domains have been investigated for translational and post-translational regulations, respectively. Hypoxia-specific gene expression systems have been applied to various ischemic disease models, including ischemic myocardium, stroke, and injured spinal cord. This review examines the current status and future challenges of hypoxia-specific systems for safe and effective gene therapy of ischemic diseases.