Intracardiac injection of a capsid-modified Ad5/35 results in decreased heart toxicity when compared to standard Ad5

Adipocyte-released adipomes in Chagas cardiomyopathy: Impact on cardiac metabolic and immune regulation

Chronic Trypanosoma cruzi infection leads to Chagas cardiomyopathy (CCM), with varying manifestations such as inflammatory hypertrophic cardiomyopathy, arrhythmias, and dilated cardiomyopathy. The factors responsible for the increasing risk of progression to CCM are not fully understood. Previous studies link adipocyte loss to CCM progression, but the mechanism triggering CCM pathogenesis remains unexplored. Our study uncovers that T. cruzi infection triggers adipocyte apoptosis, leading to the release of extracellular vesicles named "adipomes". We developed an innovative method to isolate intact adipomes from infected mice's adipose tissue and plasma, showing they carry unique lipid cargoes. Large and Small adipomes, particularly plasma-derived infection-associated L-adipomes (P-ILA), regulate immunometabolic signaling and induce cardiomyopathy. P-ILA treatment induces hypertrophic cardiomyopathy in wild-type mice and worsens cardiomyopathy severity in post-acute-infected mice by regulating adipogenic/lipogenic and mitochondrial functions. These findings highlight adipomes' pivotal role in promoting inflammation and impairing myocardial function during cardiac remodeling in CD.

Ultrasound Guided Surgery as a Refinement Tool in Oncology Research

Refinement is one of the ethical pillars of the use of animals in research. Ultrasonography is currently used in human medicine as a surgical tool for guided biopsies and this idea can be applied to preclinical research thanks to the development of specific instruments. This will eliminate the necessity of a surgical opening for implanting cells in specific organs or taking samples from tissues. The approach for the injection will depend on the target but most of the case is going to be lateral, with the probe in a ventral position and the needle going into from the lateral. This is the situation for the thyroid gland, heart, liver, spleen, kidney, pancreas, uterus, and testicles. Other approaches, such as the dorsal, can be used in the spleen or kidney. The maximum injected volume will depend on the size of the structure. For biopsies, the technical protocol is similar to the injection knowing that in big organs such as the liver, spleen, or kidney we can take several samples moving slightly the needle inside the structure. In all cases, animals must be anesthetized and minimum pain management is required after the intervention.

MicroRNA-Regulated Gene Delivery Systems for Research and Therapeutic Purposes

Targeted gene delivery relies on the ability to limit the expression of a transgene within a defined cell/tissue population. MicroRNAs represent a class of highly powerful and effective regulators of gene expression that act by binding to a specific sequence present in the corresponding messenger RNA. Involved in almost every aspect of cellular function, many miRNAs have been discovered with expression patterns specific to developmental stage, lineage, cell-type, or disease stage. Exploiting the binding sites of these miRNAs allows for construction of targeted gene delivery platforms with a diverse range of applications. Here, we summarize studies that have utilized miRNA-regulated systems to achieve targeted gene delivery for both research and therapeutic purposes. Additionally, we identify criteria that are important for the effectiveness of a particular miRNA for such applications and we also discuss factors that have to be taken into consideration when designing miRNA-regulated expression cassettes.

Intramyocardial injection of SERCA2a-expressing lentivirus improves myocardial function in doxorubicin-induced heart failure

BACKGROUND

Doxorubicin is an effective anticancer drug. The major limitation to its use is the induction of dose-dependent cardiomyopathy. No specific treatment exists for doxorubicin-induced cardiomyopathy and treatments used for other forms of heart failure have only limited beneficial effects. The contraction-relaxation cycle of the heart is controlled by cytosolic calcium concentrations, which, in turn, are critically regulated by the activity of the sarcoplasmic reticulum Ca(2) (+) ATPase (SERCA2a) pump. We hypothesized that SERCA2a gene transfer would ameliorate doxorubicin-induced cardiomyopathy.

METHODS

Lentiviral vectors LV-SERCA2a-GFP and LV-GFP were constructed and in vitro gene transfer of LV-SERCA2a-GFP confirmed SERCA2a expression by western blot analysis. Heart failure was induced by giving a single intraperitoneal injection of doxorubicin. LV-SERCA2a-GFP, LV-GFP vectors and phosphate-buffered saline (PBS) were injected under echocardiographic control to the anterior wall of the left ventricle.

RESULTS

Echocardiography analyses were performed on the injection day and 28 days postinjection. On the injection day, there were no significant differences in the average ejection fractions (EFs) among SERCA2a (40.0%), GFP (41.1%) and PBS (39.4%) injected animals. On day 28, EF in the SERCA2a group had increased by 16.6 ± 6.7% to 46.4 ± 2.1%. By contrast, EFs in the GFP (40.2 ± 1.3%) and PBS (40.6 ± 1.4%) groups remained at pre-injection levels. In addition, end systolic and end diastolic left ventricle volumes were significantly smaller in the SERCA2a group compared to controls.

CONCLUSIONS

SERCA2a gene transfer significantly improves left ventricle function and dimensions in doxorubicin-induced cardiomyopathy, thus making LV-SERCA2a gene transfer an attractive treatment modality for doxorubicin-induced heart failure. Copyright © 2016 John Wiley & Sons, Ltd.

A novel fiber chimeric conditionally replicative adenovirus-Ad5/F35 for tumor therapy

Significant progress has been made in the diagnosis and treatment of cancer; however, significant challenges remain. Conditionally replicating adenoviruses (CRAds), which not only kill cancer cells, but also serve as vectors to express therapeutic genes, are a novel and effective method to treat cancer. However, most adenoviruses are Ad5, which infect cells through the coxsackie and adenovirus receptor (CAR). The transduction efficacy of Ad5 is restricted because of the absent or low expression of CAR on several cancer cells. Ad serotype 35 has a different tropism pattern to Ad5. Ad35 attaches to cells via a non-CAR receptor, CD46, which is expressed widely on most tumor cells. Thus, chimeric adenoviral vectors consisting of the knob and shaft of Ad35 combined with Ad5 have been constructed. The chimeric fiber adenoviral vectors can transduce CAR-positive and CAR-negative cell lines. In this review, we explore the application of the novel fiber chimeric conditionally replicative adenovirus-Ad5/F35 in tumor therapy in terms of safety, mechanism, transduction efficacy, and antitumor effect.

Role of blocking ADAM10 hydrolysis site on N-cadherin by single-chain antibody in ventricular remodeling

The present study aimed to investigate the roles of the hydrolytic process of N-cadherin by A disintegrin and metalloproteases 10 (ADAM10) in sustaining myocardial structure and integrity, and discuss the mechanisms of ventricular remodeling in dilated cardiomyopathy (DCM). Single chain variable fragment antibody (ScFv) with the ability to specifically block the ADAM10 hydrolysis site of N-cadherin was designed and constructed. Western blot analysis and flow cytometry were used to detect the expression of N-cadherin and its C-terminal fragment 1 (CTF1) on cardiomyocytes, and cells were also subjected to a cell adhesion assay. Furthermore, in a rat model of dilated cardiomyopathy (DCM), the effects of intracardiac injection of the recombinant adenovirus on cardiac structure and contractile function were observed by hematoxylin and eosin staining and color Doppler echocardiography. The recombinant ScFv-expressing adenoviral plasmid with the ability to block the ADAM10 hydrolysis site on N-cadherin was successfully constructed and efficiently transfected into H9C2 cells. After transfection, N-cadherin protein expression was significantly increased, CTF1 protein was significantly decreased and the adhesion capability of myocardial cells was significantly improved. In the in vivo experiment, N-cadherin expression was significantly increased in the treatment group compared with that in the model group, and the structure and function of the heart were significantly improved. In conclusion, blocking of the ADAM10 hydrolysis site on N-cadherin by ScFv increased N-cadherin expression and improved ventricular remodeling. The present study provided experimental evidence for a novel approach for the treatment and prevention of DCM.

Intramyocardial injection of thioredoxin 2-expressing lentivirus alleviates myocardial ischemia-reperfusion injury in rats

The aim of this study is to explore the role of thioredoxin-2 (Trx2) in autophagy and apoptosis during myocardial ischemia-reperfusion (I/R) injury in vivo. In the study, adult male Sprague-Dawley rats were assigned to four groups at random and pretreated with normal saline (sham operation and I/R groups) and either a control lentivirus (Lv-GFP-N) or one expressing Trx2 (Lv-GFP-Trx2). Sevendays after pretreatment, rat MIRI models were produced via occlusion of the left anterior descending coronary artery for 30 min followed by reperfusion for 6 h. Hearts and blood were harvested to assess efficiency of lentivirus transfection via immunofluorescence staining, quantitative RT-PCR and western blotting, oxidative stress via the malondialdehyde level and superoxide dismutase activity, myocardial damage via myocardial enzymelevels and histopathological staining, myocardial apoptosis via TUNEL assays and western blotting, and myocardial autophagy viawestern blotting. Our results showed thatthe delivery of Lv-GFP-Trx2 into the myocardium remarkably increased Trx2 expression. The upregulation of Trx2 contributed to alleviation of oxidative stress, attenuation of myocardial histological damage, reduced leakage of myocardial enzyme and decrease in infarct size. Moreover, the overexpression of Trx2 was significantly associated with thedecreased incidence of apoptosis via ASK1-dependent intrinsic mitochondrial apoptotic pathwayand autophagy via the mammalian target of rapamycin (mTOR) pathway. The study indicates that upregulation of Trx2 protectsthe myocardium from MIRI and isinvolved inthe inhibition of apoptosis and autophagy. Therefore, Trx2 isa promising therapeutic strategy for attenuating MIRI.

MicroRNA-regulated viral vectors for gene therapy

Safe and effective gene therapy approaches require targeted tissue-specific transfer of a therapeutic transgene. Besides traditional approaches, such as transcriptional and transductional targeting, microRNA-dependent post-transcriptional suppression of transgene expression has been emerging as powerful new technology to increase the specificity of vector-mediated transgene expression. MicroRNAs are small non-coding RNAs and often expressed in a tissue-, lineage-, activation- or differentiation-specific pattern. They typically regulate gene expression by binding to imperfectly complementary sequences in the 3' untranslated region (UTR) of the mRNA. To control exogenous transgene expression, tandem repeats of artificial microRNA target sites are usually incorporated into the 3' UTR of the transgene expression cassette, leading to subsequent degradation of transgene mRNA in cells expressing the corresponding microRNA. This targeting strategy, first shown for lentiviral vectors in antigen presenting cells, has now been used for tissue-specific expression of vector-encoded therapeutic transgenes, to reduce immune response against the transgene, to control virus tropism for oncolytic virotherapy, to increase safety of live attenuated virus vaccines and to identify and select cell subsets for pluripotent stem cell therapies, respectively. This review provides an introduction into the technical mechanism underlying microRNA-regulation, highlights new developments in this field and gives an overview of applications of microRNA-regulated viral vectors for cardiac, suicide gene cancer and hematopoietic stem cell therapy, as well as for treatment of neurological and eye diseases.

Efficacy and safety of myocardial gene transfer of adenovirus, adeno-associated virus and lentivirus vectors in the mouse heart

Gene therapy is a promising new treatment option for cardiac diseases. For finding the most suitable and safe vector for cardiac gene transfer, we delivered adenovirus (AdV), adeno-associated virus (AAV) and lentivirus (LeV) vectors into the mouse heart with sophisticated closed-chest echocardiography-guided intramyocardial injection method for comparing them with regards to transduction efficiency, myocardial damage, effects on the left ventricular function and electrocardiography (ECG). AdV had the highest transduction efficiency in cardiomyocytes followed by AAV2 and AAV9, and the lowest efficiency was seen with LeV. The local myocardial inflammation and fibrosis in the left ventricle (LV) was proportional to transduction efficiency. AdV caused LV dilatation and systolic dysfunction. Neither of the locally injected AAV serotypes impaired the LV systolic function, but AAV9 caused diastolic dysfunction to some extent. LeV did not affect the cardiac function. We also studied systemic delivery of AAV9, which led to transduction of cardiomyocytes throughout the myocardium. However, also diffuse fibrosis was present leading to significantly impaired LV systolic and diastolic function and pathological ECG changes. Compared with widely used AdV vector, AAV2, AAV9 and LeV were less effective in transducing cardiomyocytes but also less harmful. Local administration of AAV9 was safer and more efficient compared with systemic administration.

Gene electro transfer of plasmid encoding vascular endothelial growth factor for enhanced expression and perfusion in the ischemic swine heart

Myocardial ischemia can damage heart muscle and reduce the heart's pumping efficiency. This study used an ischemic swine heart model to investigate the potential for gene electro transfer of a plasmid encoding vascular endothelial growth factor for improving perfusion and, thus, for reducing cardiomyopathy following acute coronary syndrome. Plasmid expression was significantly greater in gene electro transfer treated tissue compared to injection of plasmid encoding vascular endothelial growth factor alone. Higher gene expression was also seen in ischemic versus non-ischemic groups with parameters 20 Volts (p<0.03), 40 Volts (p<0.05), and 90 Volts (p<0.05), but not with 60 Volts (p<0.09) while maintaining a pulse width of 20 milliseconds. The group with gene electro transfer of plasmid encoding vascular endothelial growth factor had increased perfusion in the area at risk compared to control groups. Troponin and creatine kinase increased across all groups, suggesting equivalent ischemia in all groups prior to treatment. Echocardiography was used to assess ejection fraction, cardiac output, stroke volume, left ventricular end diastolic volume, and left ventricular end systolic volume. No statistically significant differences in these parameters were detected during a 2-week time period. However, directional trends of these variables were interesting and offer valuable information about the feasibility of gene electro transfer of vascular endothelial growth factor in the ischemic heart. The results demonstrate that gene electro transfer can be applied safely and can increase perfusion in an ischemic area. Additional study is needed to evaluate potential efficacy.