Current Gene Therapy - Volume 17, Issue 3, 2017

Introduction: The recent approval of Spinraza (nusinersen), an antisense oligonucleotide, by U.S. Food and Drug Administration to treat patients with spinal muscular atrophy, has reignited interests of researchers in designing and testing new gene therapy approaches to treat neurological disorders, in particular, to curb neurodegenerative diseases of the central nervous system which represent an ever-increasing public health burden to today's society. Conclusion: This review highlights several key factors to be taken into consideration to design successful preclinical and clinical gene therapy experiments with respect to the vehicle of delivery and the route of administration to CNS-specific targets, with an additional focus on antisense oligonucleotide therapy and recent clinical trial developments.

Background: Gene therapy represents the therapeutic delivery of nucleic acid polymers into patient cells with the aim of treating an underlying disease. Over the past 2 decades this new therapy has made substantial progress owing to better understanding of the pathobiologic basis of various diseases coupled with growth of gene transfer biotechnologies. The eye, in particular, represents a suitable target for such therapy due to the immune privilege provided by the blood-ocular barrier, the ability to directly visualize, access and locally treat the cells and the minimal amount of vector needed given the size of this organ. It is not surprising therefore that several clinical trials are now ongoing in this field. Objective: The purpose of this review was to provide an update on gene therapy for retinal diseases, discussing differences in treatment strategies, vector designs and surgical techniques. Method: Research was performed on PubMed, ClinicalTrials.gov, and Home Genetic Reference. We additionally utilized the internet database for genetics of retinal diseases, the portal for rare diseases and orphan drugs and the NCBI database Online Mendelian Inheritance in Man. No restriction was applied on the language of publications. Results: We present the available results of current active clinical trials for inherited retinal disease such as Leber's congenital amaurosis type 2, choroideremia, Stargardt disease, achromatopsia and juvenile X-linked retinoschisis. We also illustrate a new approach of this therapy for the treatment of much more common ocular diseases such as age-related macular degeneration and diabetic retinopathy. Conclusion: Gene therapy represents an emerging and promising therapeutic approach for the treatment not only of rare inherited retinal diseases but also much more common retinal pathologies.

Introduction: Metabolic Syndrome (MS) is a global socioeconomic problem rapidly progressing in accordance with increasing Body Mass Index (BMI) and age. It is a consortium of risk factors, such as dyslipidaemia, insulin resistance, leptin resistance, reduced adiponectin, glucose intolerance, hyperglycemia, and hypertension. Collectively, these factors accelerate the onset of type 2 diabetes mellitus, cardiovascular disease, stroke, and certain cancers such as breast, liver pancreatic, and colon cancer. Extracellular Matrix (ECM) and basement membrane remodeling play a central role during pathogenesis of MS as they regulate diverse cell functions including proliferation, differentiation, and migration. Therefore, regulation of proteins that remodel the ECM offers promising therapeutic opportunities for most of the MS. Matrix Metalloproteinases (MMPs), a family of zinc dependent endopeptidases, are the main enzymes involved in ECM remodeling. Emerging studies have reported altered levels of MMPs and the Tissue Inhibitors of Metalloproteinases (TIMPs) during MS. A number of pharmaceutical MMP inhibitors are being developed, but they have yet to be recognized for clinical applications. Conclusion: Recently, microRNAs (~21–23-nucleotide, small non-coding, endogenous, single-stranded RNAs) have emerged as a class of promising entities for therapeutic intervention due to their ability to manipulate gene expression. The combined strategy of targeting ECM remodeling through regulation of MMPs by small non-coding RNA has produced encouraging results in pre-clinical studies for cancer and cardiovascular diseases. This review serves to provide insight into the role of microRNAs as modulators of MS and their potential as therapeutics tool through direct and indirect interactions with the MMPs.

Introduction: Parathyroid Hormone (PTH) is an effective therapeutic agent for osteoporosis, but the treatment requires long-term daily injections. Oral gene delivery is a less invasive alternative to daily injections. Objective: The aim of this study is to investigate the effect of orally administered nonionic polymeric micelles of plasmid cDNA containing human cytomegalovirus promoter (PCMV)-PTH (1-34) plus EDTA on body mineral density and bone microstructure in ovariectomized rats. Material and Methods: A total of 27 Spraque-Dawley female rats were subjected to a bilateral ovariectomy. One month following the ovariectomy, they were randomly assigned to three groups: (1) (PCMVPTH (1-34) cDNA in polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO-PEO) polymeric micelle formations plus EDTA); (2) PCMV-PTH (1-34) cDNA and (3) drinking water. The treatment was administered by oral gavage on day 1, 2, 7, 14, and 21 at 8-hour intervals. Body mineral density, bone volume fraction, and trabecular thickness of the lumbar spine and femoral neck were examined with peripheral quantitative computed tomography at pre- and post-intervention (3 months after the start of the intervention) and analyzed using two-way repeated measures analysis of variance. Results: Results showed that bone mineral density, bone volume fraction and trabecular thickness were significantly increased in Group 1 over time, compared with those in Group 2 and Group 3. Conclusion: In conclusion, significantly improved bone mineral density and bone microstructure were observed in ovariectomized rats treated with PTH (1-34) cDNA delivered by nonionic polymeric micelles.

Background: The eye possesses unique anatomical features that make it a valuable target for gene therapy applications. Objective: The aim of the current study was to compare transduction efficiency, safety and biodistribution of four viral vectors following intravitreal injection. Method: Adenovirus (AdV), Adeno-Associated Virus (AAV), Baculovirus (BV) and Lentivirus (LV) vectors encoding Green Fluorescent Protein (GFP) were injected bilaterally intravitreally into adult C57BL/6OlaHsd mice. Control mice received saline. Eyes and other organs were studied at multiple time points from 3 days to 6 months. Immunohistochemical stainings with retinal cell markers were performed to verify GFP-positive cells. Biodistribution in retina and various non-target tissues was studied using a qPCR method. Inflammatory responses and toxicity were investigated from cryostat eye sections and serum samples. Results: AAV-injected eyes showed GFP expression both in inner and outer retinal cells from 7 days up to 6 months. LV eyes showed long lasting transgene expression mostly in retinal pigment epithelium whereas AdV transiently transduced mainly cells in the anterior chamber. In BV-injected eyes, GFP positivity was very low. qPCR results showed that AdV, AAV and LV spread into the optic nerve, but were below the detection limit in other organs. The strongest immune responses were evoked by intravitreal injections of AdV and BV. The highest concentration of anti-GFP IgG was detected in the AdV-treated group, whereas the AAV group showed the lowest concentration. Neither blood chemistry screen nor the number of apoptotic cells showed any differences between the viral vector and saline injected groups. Conclusion: Our findings show that intravitreal gene delivery is safe and feasible with AAV, AdV and lentivirus vectors.

Aims: The aim of the present study was to assess how genetically increased Sarcoplasmic reticulum Ca2+-ATPase (Serca2a) expression affects cardiac injury after Ischemia/Reperfusion (I/R) exposure and the related mechanisms involved. Methods and Results: Rats were subjected to Left Anterior Descending coronary artery (LAD) occlusion for 30 min followed by a 24-hour reperfusion. Cardiac function analysis revealed that cardiac function dramatically improved in Serca2a transgenic rats, (Serca2aTG) rats, compared to Wild Type (WT) rats. Serca2aTG rats developed a significantly smaller myocardial infarction size compared to those in WT group. The expression of the Bcl-2 was lower in Serca2aTG rats compared with WT rats; but, Bcl-2 expression was markedly increased in Serca2aTG rats compared with WT after I/R. In addition, Bax was markedly downregulated in Serca2aTG rats compared to WT group after I/R. Meanwhile, autophagy marker LC-3B was increased in Serca2aTG group, and p62 was only increased in WT group but not in Serca2aTG group in response to I/R. Electron microscope observation confirmed that there were more autophagosomes in Serca2aTG group than in WT rats after I/R. Conclusion: our findings demonstrated that the overexpression of Serca2a plays an important role in myocardial protection from I/R injury and postischemic functional recovery, which may be via antinecrotic, anti-apoptotic and pro-autophagy signal pathways. Our research provides solid basic data and new perspective on clinical treatment in heart failure patients with long-term over-expression of Serca2a.