Gene delivery into primary T cells: overview and characterization of a transgenic model for efficient adenoviral transduction

Inhibition of miR-153 ameliorates ischemia/reperfusion-induced cardiomyocytes apoptosis by regulating Nrf2/HO-1 signaling in rats

Background

Previous in vitro studies demonstrated that suppression of microRNAs might protect cardiomyocytes and neurons against oxygen–glucose deprivation and reoxygenation (OGD/R)-induced cell apoptosis. However, whether the protective effect of miR-153-inhibition on cardiomyocytes can be observed in the animal model is unknown. We aimed to address this question using a rat model of ischemia–reperfusion (I/R).

Methods

Rats were received the intramyocardial injection of saline or adenovirus-carrying target or control gene, and the rats were subjected to ischemia/reperfusion (I/R) treatment. The effects of miR-153 on I/R-induced inflammatory response and oxidative stress in the rat model were assessed using various assays.

Results

We found that suppression of miR-153 decreased cleaved caspase-3 and Bcl-2-associated X (Bax) expression, and increased B cell lymphoma 2 (Bcl-2) expression. We further confirmed that Nuclear transcription factor erythroid 2-like 2 (Nrf2) is a functional target of miR-153, and Nrf2/Heme oxygenase-1 (HO-1) signaling was involved in miR-153-regulated I/R-induced cardiomyocytes apoptosis. Inhibition of miR-153 reduced I/R-induced inflammatory response and oxidative stress in rat myocardium.

Conclusion

Suppression of miR-153 exerts a cardioprotective effect against I/R-induced injury through the regulation of Nrf2/HO-1 signaling, suggesting that targeting miR-153, Nrf2, or both may serve as promising therapeutic targets for the alleviation of I/R-induced injury.

Adenovirus vectors in hematopoietic stem cell genome editing

Genome editing of hematopoietic stem cells (HSCs) represents a therapeutic option for a number of hematological genetic diseases, as HSCs have the potential for self-renewal and differentiation into all blood cell lineages. This review presents advances of genome editing in HSCs utilizing adenovirus vectors as delivery vehicles. We focus on capsid-modified, helper-dependent adenovirus vectors that are devoid of all viral genes and therefore exhibit an improved safety profile. We discuss HSC genome engineering for several inherited disorders and infectious diseases including hemoglobinopathies, Fanconi anemia, hemophilia, and HIV-1 infection by ex vivo and in vivo editing in transgenic mice, nonhuman primates, as well as in human CD34+ cells. Mechanisms of therapeutic gene transfer including episomal expression of designer nucleases and base editors, transposase-mediated random integration, and targeted homology-directed repair triggered integration into selected genomic safe harbor loci are also reviewed.

Cloning Gene Variants and Reporter Assays

Recent advances have identified new genetic markers associated with the inheritance of celiac disease. These non-HLA target regions remain to be fully categorized. Investigation of associated SNPs indicates that the causal variants may alter specific gene expression. Thus, closer examination of potential causal variants found within regulatory regions could provide data relating to the mechanistic association. Molecular cloning is an established fundamental tool that enables investigators to examine the differential potential at a variant site. In conjunction with reporter gene assays, SNPs affecting gene expression can be uncovered and contribute to our understanding of the underlying pathogenic mechanisms. This chapter outlines the protocols necessary to clone risk variants and transfect these constructs into a T cell line for reporter assay analysis.

Advances in siRNA delivery to T-cells: potential clinical applications for inflammatory disease, cancer and infection

The specificity of RNAi and its ability to silence ‘undruggable’ targets has made inhibition of gene expression in T-cells with siRNAs an attractive potential therapeutic strategy for the treatment of inflammatory disease, cancer and infection. However, delivery of siRNAs into primary T-cells represents a major hurdle to their use as potential therapeutic agents. Recent advances in siRNA delivery through the use of electroporation/nucleofection, viral vectors, peptides/proteins, nanoparticles, aptamers and other agents have now enabled efficient gene silencing in primary T-cells both in vitro and in vivo. Overcoming such barriers in siRNA delivery offers exciting new prospects for directly targeting T-cells systemically with siRNAs, or adoptively transferring T-cells back into patients following ex vivo manipulation with siRNAs. In the present review, we outline the challenges in delivering siRNAs into primary T-cells and discuss the mechanism and therapeutic opportunities of each delivery method. We emphasize studies that have exploited RNAi-mediated gene silencing in T-cells for the treatment of inflammatory disease, cancer and infection using mouse models. We also discuss the potential therapeutic benefits of manipulating T-cells using siRNAs for the treatment of human diseases.

Generation of CD4CreER(T²) transgenic mice to study development of peripheral CD4-T-cells

After thymic emigration CD4-T-cells continue to differentiate into multiple effector and suppressor sublineages in peripheral lymphoid organs. In vivo analysis of peripheral CD4-T-cell differentiation has relied on animal models with targeted gene mutations. These are expressed either constitutively or conditionally after Cre mediated recombination. Available Cre transgenic strains to specifically target T-cells act at stages of thymocyte development that precede thymic selection. Tracing gene functions in CD4-T-cell development after thymic exit becomes complicated when the targeted gene is essential during thymic development. Other approaches to conditionally modify gene functions in peripheral T-cells involve infection of in vitro activated cells with Cre expressing lenti-, retro-, or adenoviruses, which precludes in vivo analyses. To study molecular mechanisms of peripheral CD4-T-cell differentiation in vivo and in vitro we generated transgenic mice expressing a tamoxifen inducible Cre recombinase (CreER(T2) ) under the control of the CD4 gene promoter. We show here that in CD4CreER(T2) mice Cre is inducibly and selectively activated in CD4-T-cells. Tamoxifen treatment both in vivo and in vitro results in efficient recombination of loci marked by LoxP sites. Moreover, this strain shows no abnormalities related to transgene insertion. Therefore it provides a valuable tool for studying gene function during differentiation of naïve peripheral CD4-T-cells into effector or suppressor sub-lineages.

Laser scanning cytometry: capturing the immune system in situ

Until recently, it has not been possible to image and functionally correlate the key molecular and cellular events underpinning immunity and tolerance in the intact immune system. Certainly, the field has been revolutionized by the advent of tetramers to identify physiologically relevant specificities of T cells, and the introduction of models in which transgenic T-cell receptor and/or B-cell receptor-bearing lymphocytes are adoptively transferred into normal mice and can then be identified by clonotype-specific antibodies using flow cytometry in vitro, or immunohistochemistry ex vivo. However, these approaches do not allow for quantitative analysis of the precise anatomical, phenotypic, signaling, and functional parameters required for dissecting the development of immune responses in health and disease in vivo. Traditionally, assessment of signal transduction pathways has required biochemical or molecular biological analysis of isolated and highly purified subsets of immune system cells. Inevitably, this creates potential artifacts and does not allow identification of the key signaling events for individual cells present in their microenvironment in situ. These difficulties have now been overcome by new methodologies in cell signaling analysis that are sufficiently sensitive to detect signaling events occurring in individual cells in situ and the development of technologies such as laser scanning cytometry that provide the tools to analyze physiologically relevant interactions between molecules and cells of the innate and the adaptive immune system within their natural environmental niche in vivo.

Distinct regulation of integrin-dependent T cell conjugate formation and NF-kappa B activation by the adapter protein ADAP

Following TCR stimulation, T cells utilize the hematopoietic specific adhesion and degranulation-promoting adapter protein (ADAP) to control both integrin adhesive function and NF-kappaB transcription factor activation. We have investigated the molecular basis by which ADAP controls these events in primary murine ADAP(-/-) T cells. Naive DO11.10/ADAP(-/-) T cells show impaired adhesion to OVAp (OVA aa 323-339)-bearing APCs that is restored following reconstitution with wild-type ADAP. Mutational analysis demonstrates that the central proline-rich domain and the C-terminal domain of ADAP are required for rescue of T:APC conjugate formation. The ADAP proline-rich domain is sufficient to bind and stabilize the expression of SKAP55 (Src kinase-associated phosphoprotein of 55 kDa), which is otherwise absent from ADAP(-/-) T cells. Interestingly, forced expression of SKAP55 in the absence of ADAP is insufficient to drive T:APC conjugate formation, demonstrating that both ADAP and SKAP55 are required for optimal LFA-1 function. Additionally, the ADAP proline-rich domain is required for optimal Ag-induced activation of CD69, CD25, and Bcl-x(L), but is not required for assembly of the CARMA1/Bcl10/Malt1 (caspase-recruitment domain (CARD) membrane-associated guanylate kinase (MAGUK) protein 1/B-cell CLL-lymphoma 10/mucosa-associated lymphoid tissue lymphoma translocation protein 1) signaling complex and subsequent TCR-dependent NF-kappaB activity. Our results indicate that ADAP is used downstream of TCR engagement to delineate two distinct molecular programs in which the ADAP/SKAP55 module is required for control of T:APC conjugate formation and functions independently of ADAP/CARMA1-mediated NF-kappaB activation.

Inhibition of HIV replication: A powerful antiviral strategy by IFN-β gene delivery in CD4+ cells

In this study, we demonstrated the efficiency and feasibility of a gene therapy protocol against HIV infection using the antiviral effects of IFN-beta expression. Lentiviral vectors containing the human or the simian IFN-beta sequences under the influence of the murine moderate H2-kb promoter were constructed. To examine the capacity of IFN-beta to inhibit the replication of HIV in human CD4(+) cells, a transduction protocol permitting to efficiently transduce CD4(+) cells or PBMC (85+/-12% of CD4(+)-transduced cells) with a moderate expression of IFN-beta was developed. Results indicate that enforced expression of IFN-beta has no negative effects in terms of apoptosis and proliferation. In human CD4(+) cells, it drastically inhibits (up to 99.9%) replication after challenging with different strains of HIV-1. The expression of exogenous IFN-beta leads to an amplification of the CD4(+) cells (11-fold) and to a drastic decrease of the p24 protein. Micro-array analyses indicated that antiviral effect of IFN-beta could be due to a major regulation of the inflammatory response. These results are encouraging for the development of a clinical study of gene therapy against AIDS using IFN-beta.

Cellular vehicles for cancer gene therapy: current status and future potential

Cancer is a difficult target for any therapeutic strategy; therefore, there is a continuous search for new therapeutic modalities, for application either alone or in combination. In this regard, gene-based therapy is a new approach that offers hope of improved control of tumors. Intensive research to apply gene therapy for cancer treatment has led to identification of the most important technical and theoretical barriers that need to be overcome for clinical success. One of the central unresolved challenges remains the issue of specific and efficient delivery of genes to target cells or tissues, emphasizing the importance of the gene carrier. Along with different viral and non-viral vector systems, mammalian cells have also been considered as vehicles for delivery of anti-cancer therapeutics. The cell-based delivery approach was introduced as the first attempt to apply gene therapy to cancer treatment, and in general, has followed most of the ups and downs of gene therapy applications, progressing alongside new knowledge gained in this field. As a result, significant progress has been made in some aspects of the cell-based approach, while the development of other essential issues is only just gaining speed. It appears that the initial phase of development of cell-based protocols - the achievement of efficient ex vivo cell loading with therapeutics - has largely been fulfilled. However, the desired efficacy of cell-based strategies in general has not yet been reached, and specificity of tumor homing needs to be improved considerably. There is hope that advances in related scientific fields will promote the utilization of cells as powerful and versatile vehicles for cancer gene therapy.

Nanoparticulate System for Efficient Gene Transfer into Refractory Cell Targets

A biocompatible, nanoparticulate formulation has been designed to retain, protect, and deliver adenoviral gene constructs over an extended time course. Such devices can be administered locally or systemically with low toxicity. A multipolymeric nanoparticulate system, featuring very high stability in physiologic media, was designed to allow efficient in vitro gene transfer. The efficacy of nanoparticulate delivery is effective in cell systems that are normally refractory to gene transfer, such as pancreatic islets and antigen-presenting cells. The findings suggest a nonspecific uptake system that permits adenoviral particle release within the transfected cells. A comparison with literature data revealed that our system is efficient at much lower levels (at least three orders of magnitude) of infectious viral particles.

In vivo antitumour activity of PBMCs via genetic modification of single-chain immunotoxin

AIM

To investigate In vivo antitumour activity of single-chain immunotoxin (sFv-TNF-α fusion protein).

METHODS

HCC-specific killer cells were generated by transducing the recombinant retroviral virus in supernatant of the virus producing cells (C₂₂) into human peripheral blood mononuclear cells (PBMCs). SMMC-7721 xenograft nude mice were given iv either 1×10⁶ (0.2 mL) transduced or mock-transduced PBMCs once five days for three weeks and tumour growth was detected.

RESULTS

Tumour growth were (20.8±4.9) mg/d in PBMCs/PST group and (28.5±6.7)mg/d in PBMCs/ pLXSN group, with a significant difference (P<0.05).

CONCLUSION

Genetic modification of PBMCs by single-chain immunotoxin has antitumour activity In vivo.

In vitro cytotoxicity of PBMCs via genetic modification of single-chain immunotoxin

AIM: To investigate the selective cytotoxicity of single-chain immunotoxin (sFv-TNF-α fusion proteins) in cell line SMMC-7721.

METHODS: HCC-specific killer cells were generated by transducing the recombinant retroviral virus in supernatant of the virus producing cells into human peripheral blood mononuclear cells (PBMCs). PCR and RT-PCR were used to detect integration and transcription of the sFv-TNF-α gene in transduced PBMCs (PBMCs/PST). MTT method was used to detect antitumour activity of the sFv-TNF-α fusion proteins.

RESULTS: There was integrated sFv-TNF-α gene in the genome of PBMCs/PST, and PBMCs/PST were able to express the fusion sFv-TNF-α proteins. Cell killing was significant in HCC cells co-cultivated with PBMCs/PST, whereas the PBMCs/pLXSN control cells had no significant cytotoxic effects on HCC cells.

CONCLUSION: Expression of sFv-TNF-α fusion proteins in PBMCs/PST has cytotoxicity to HCC cells in vitro.