Adenovirus mediated IL-10 gene transfer to the airway of the rat lung for prevention of lung allograft rejection

Creating superior lungs for transplantation with next-generation gene therapy during ex vivo lung perfusion

Engineering donor organs to better tolerate the harmful non-immunological and immunological responses inherently related to solid organ transplantation would improve transplant outcomes. Our enhanced knowledge of ischemia-reperfusion injury, alloimmune responses and pathological fibroproliferation after organ transplantation, and the advanced toolkit available for gene therapies, have brought this goal closer to clinical reality. Ex vivo organ perfusion has evolved rapidly especially in the field of lung transplantation, where clinicians routinely use ex vivo lung perfusion (EVLP) to confirm the quality of marginal donor lungs before transplantation, enabling safe transplantation of organs originally considered unusable. EVLP would also be an attractive platform to deliver gene therapies, as treatments could be administered to an isolated organ before transplantation, thereby providing a window for sophisticated organ engineering while minimizing off-target effects to the recipient. Here, we review the status of lung transplant first-generation gene therapies that focus on inducing transgene expression in the target cells. We also highlight recent advances in next-generation gene therapies, that enable gene editing and epigenetic engineering, that could be used to permanently change the donor organ genome and to induce widespread transcriptional gene expression modulation in the donor lung. In a future vision, dedicated organ repair and engineering centers will use gene editing and epigenetic engineering, to not only increase the donor organ pool, but to create superior organs that will function better and longer in the recipient.

Effect of β-Nicotinamide Adenine Dinucleotide on Acute Allograft Rejection After Rat Lung Transplantation

Acute rejection is still a major limitation for a successful outcome in lung transplantation. Since β-nicotinamide adenine dinucleotide (NAD+) has been shown to have various immunomodulatory properties on the innate and adaptive immune system, we evaluate here a potential protective effect of NAD+ against acute lung rejection.

Methods

Rat single-lung transplantation was performed in 2 groups (n = 8 per group), using Brown-Norway donors and major histocompatibility complex-mismatched Lewis recipients. Recipients of the NAD+ group received 1000 mg/kg NAD+ intraperitoneally before transplantation and daily thereafter until euthanasia, whereas the control group received saline solution. At autopsy on day 5, blood samples were analyzed and the lung allograft was assessed by bronchioalveolar lavage, histology, and immunochemistry.

Results

The NAD+ group maintained an intact compliant lung tissue, a strong trend of lower acute cellular rejection (A3 versus A3-A4) and significantly less lymphocytic bronchiolitis (B0-B2R versus B1R-Bx). In addition, a trend of fewer alveolar CD68+ macrophages and significantly fewer interstitial CD163+ macrophages was observed. Bronchoalveolar lavage in the NAD+ group showed significantly fewer proinflammatory cytokines interleukin (IL)-6, IL-13, TNFα, and a protective IL-6/IL-10-ratio. In blood samples, we observed significantly fewer neutrophils, and proinflammatory GRO/KC in the NAD+ group.

Conclusions

NAD+ might be a promising substance in prevention of acute allograft rejection in lung transplantation.

Gene Therapy: Will the Promise of Optimizing Lung Allografts Become Reality?

Lung transplantation is the definitive therapy for patients living with end-stage lung disease. Despite significant progress made in the field, graft survival remains the lowest of all solid organ transplants. Additionally, the lung has among the lowest of organ utilization rates-among eligible donors, only 22% of lungs from multi-organ donors were transplanted in 2019. Novel strategies are needed to rehabilitate marginal organs and improve graft survival. Gene therapy is one promising strategy in optimizing donor allografts. Over-expression or inhibition of specific genes can be achieved to target various pathways of graft injury, including ischemic-reperfusion injuries, humoral or cellular rejection, and chronic lung allograft dysfunction. Experiments in animal models have historically utilized adenovirus-based vectors and the majority of literature in lung transplantation has focused on overexpression of IL-10. Although several strategies were shown to prevent rejection and prolong graft survival in preclinical models, none have led to clinical translation. The past decade has seen a renaissance in the field of gene therapy and two AAV-based in vivo gene therapies are now FDA-approved for clinical use. Concurrently, normothermic ex vivo machine perfusion technology has emerged as an alternative to traditional static cold storage. This preservation method keeps organs physiologically active during storage and thus potentially offers a platform for gene therapy. This review will explore the advantages and disadvantages of various gene therapy modalities, review various candidate genes implicated in various stages of allograft injury and summarize the recent efforts in optimizing donor lungs using gene therapy.

Viral Vector Mediated Interleukin-10 Gene Transfer in Skin Allograft

BACKGROUND

Expression of genes with immunoregulatory capacity can potentially decrease rejection of allograft. According to recent studies, viral interleukin (IL)-10 can reduce immune response during allotransplantation and is one of the most promising methods for the prevention of rejection. Our study aimed to analyze the immunosuppressive potential of recombinant adenovirus-mediated rat IL-10 in rat skin allograft.

METHODS

We performed skin graft surgery 1 hour after infecting the donated skin with adenovirus-mediated rat IL-10. On day 7 postoperatively, the skin allografts were harvested, and acute rejection was graded histologically.

RESULTS

Viral IL-10 gene transfer into rat skin allografts improved graft survival and reduced acute rejections.

CONCLUSION

The results of our study suggest that the therapeutic potential of graft viral IL-10 gene transfer is an effective immunosuppressive method for preventing skin allograft rejection.

A novel combined ex vivo and in vivo lentiviral interleukin-10 gene delivery strategy at the time of transplantation decreases chronic lung allograft rejection in mice

OBJECTIVE

Our objective was to develop a rapid-onset and durable gene-delivery strategy that is applicable at the time of transplant to determine its effects on both acute rejection and chronic lung allograft fibrosis using a mouse orthotopic lung transplant model.

METHODS

C57BL/6 mice received an orthotopic left lung transplant from syngeneic donors or C57BL/10 donors. By using syngeneic lung transplantation, we established a novel gene transfer protocol with lentivirus luciferase intrabronchial administration to the donor lung ex vivo before transplantation. This strategy was applied in allogeneic lung transplantation with lentivirus engineering expression of human interleukin-10 or lentivirus luciferase (control).

RESULTS

Bioluminescent imaging revealed that the highest early transgene expression was achieved when lentivirus luciferase was administered both directly into the donor lung graft ex vivo before implantation and subsequently to the recipient in vivo daily on post-transplant days 1 to 4, compared with post-transplant in vivo administration only (days 0 to 4). Our previous work with adenoviral interleukin-10 gene therapy indicates that early interleukin-10 expression in the allograft is desirable. Therefore, we selected the combined protocol for human interleukin-10 encoding lentiviral vector therapy. In the allogeneic transplant setting, ex vivo and in vivo human interleukin-10 encoding lentiviral vector therapy reduced acute rejection grade (2.0 vs 3.0, P < .05) at day 28. The percentage of fibrotic obliterated airways was reduced in the human interleukin-10 encoding lentiviral vector-treated group (10.9% ± 7.7% vs 40.9% ± 9.3%, P < .05).

CONCLUSIONS

Delivery of lentiviral interleukin-10 gene therapy, using a novel combined ex vivo and in vivo delivery strategy, significantly improves acute and chronic rejection in the mouse lung transplant model.

An observational study of Donor Ex Vivo Lung Perfusion in UK lung transplantation: DEVELOP-UK

BACKGROUND

Many patients awaiting lung transplantation die before a donor organ becomes available. Ex vivo lung perfusion (EVLP) allows initially unusable donor lungs to be assessed and reconditioned for clinical use.

OBJECTIVE

The objective of the Donor Ex Vivo Lung Perfusion in UK lung transplantation study was to evaluate the clinical effectiveness and cost-effectiveness of EVLP in increasing UK lung transplant activity.

DESIGN

A multicentre, unblinded, non-randomised, non-inferiority observational study to compare transplant outcomes between EVLP-assessed and standard donor lungs.

SETTING

Multicentre study involving all five UK officially designated NHS adult lung transplant centres.

PARTICIPANTS

Patients aged ≥ 18 years with advanced lung disease accepted onto the lung transplant waiting list.

INTERVENTION

The study intervention was EVLP assessment of donor lungs before determining suitability for transplantation.

MAIN OUTCOME MEASURES

The primary outcome measure was survival during the first 12 months following lung transplantation. Secondary outcome measures were patient-centred outcomes that are influenced by the effectiveness of lung transplantation and that contribute to the health-care costs.

RESULTS

Lungs from 53 donors unsuitable for standard transplant were assessed with EVLP, of which 18 (34%) were subsequently transplanted. A total of 184 participants received standard donor lungs. Owing to the early closure of the study, a non-inferiority analysis was not conducted. The Kaplan-Meier estimate of survival at 12 months was 0.67 [95% confidence interval (CI) 0.40 to 0.83] for the EVLP arm and 0.80 (95% CI 0.74 to 0.85) for the standard arm. The hazard ratio for overall 12-month survival in the EVLP arm relative to the standard arm was 1.96 (95% CI 0.83 to 4.67). Patients in the EVLP arm required ventilation for a longer period and stayed longer in an intensive therapy unit (ITU) than patients in the standard arm, but duration of overall hospital stay was similar in both groups. There was a higher rate of very early grade 3 primary graft dysfunction (PGD) in the EVLP arm, but rates of PGD did not differ between groups after 72 hours. The requirement for extracorporeal membrane oxygenation (ECMO) support was higher in the EVLP arm (7/18, 38.8%) than in the standard arm (6/184, 3.2%). There were no major differences in rates of chest radiograph abnormalities, infection, lung function or rejection by 12 months. The cost of EVLP transplants is approximately £35,000 higher than the cost of standard transplants, as a result of the cost of the EVLP procedure, and the increased ECMO use and ITU stay. Predictors of cost were quality of life on joining the waiting list, type of transplant and number of lungs transplanted. An exploratory model comparing a NHS lung transplant service that includes EVLP and standard lung transplants with one including only standard lung transplants resulted in an incremental cost-effectiveness ratio of £73,000. Interviews showed that patients had a good understanding of the need for, and the processes of, EVLP. If EVLP can increase the number of usable donor lungs and reduce waiting, it is likely to be acceptable to those waiting for lung transplantation. Study limitations include small numbers in the EVLP arm, limiting analysis to descriptive statistics and the EVLP protocol change during the study.

CONCLUSIONS

Overall, one-third of donor lungs subjected to EVLP were deemed suitable for transplant. Estimated survival over 12 months was lower than in the standard group, but the data were also consistent with no difference in survival between groups. Patients receiving these additional transplants experience a higher rate of early graft injury and need for unplanned ECMO support, at increased cost. The small number of participants in the EVLP arm because of early study termination limits the robustness of these conclusions. The reason for the increased PGD rates, high ECMO requirement and possible differences in lung injury between EVLP protocols needs evaluation.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN44922411.

FUNDING

This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 20, No. 85. See the NIHR Journals Library website for further project information.

Construction of PLGA Nanoparticles Coated with Polycistronic SOX5, SOX6, and SOX9 Genes for Chondrogenesis of Human Mesenchymal Stem Cells

Transfection of a cocktail of genes into cells has recently attracted attraction in stem cell differentiation. However, it is not easy to control the transfection rate of each gene. To control and regulate gene delivery into human mesenchymal stem cells (hMSCs), we employed multicistronic genes coupled with a nonviral gene carrier system for stem cell differentiation. Three genes, SOX5, SOX6, and SOX9, were successfully fabricated in a single plasmid. This multicistronic plasmid was complexed with the polycationic polymer polyethylenimine, and poly(lactic-co-glycolic) acid (PLGA) nanoparticles were coated with this complex. The uptake of PLGA nanoparticles complexed with the multicistronic plasmid was tested first. Thereafter, transfection of SOX5, SOX6, and SOX9 was evaluated, which increased the potential for chondrogenesis of hMSCs. The expression of specific genes triggered by transfection of SOX5, SOX6, and SOX9 was tested by RT-PCR and real-time qPCR. Furthermore, specific proteins related to chondrocytes were investigated by a glycosaminoglycan/DNA assay, Western blotting, histological analyses, and immunofluorescence staining. These methods demonstrated that chondrogenesis of hMSCs treated with PLGA nanoparticles carrying this multicistronic genes was better than that of hMSCs treated with other carriers. Furthermore, the multicistronic genes complexed with PLGA nanoparticles were more simple than that of each single gene complexation with PLGA nanoparticles. Multicistronic genes showed more chondrogenic differentiation than each single gene transfection methods.

Non-viral gene therapy for myocardial engineering

Despite significant advances in surgical and pharmacological techniques, myocardial infarction (MI) remains the main cause of morbidity in the developed world because no remedy has been found for the regeneration of infarcted myocardium. Once the blood supply to the area in question is interrupted, the inflammatory cascade, among other mechanisms, results in the damaged tissue becoming a scar. The goals of cardiac gene therapy are essentially to minimize damage, to promote regeneration, or some combination thereof. While the vector is, in theory, less important than the gene being delivered, the choice of vector can have a significant impact. Viral therapies can have very high transfection efficiencies, but disadvantages include immunogenicity, retroviral-mediated insertional mutagenesis, and the expense and difficulty of manufacture. For these reasons, researchers have focused on non-viral gene therapy as an alternative. In this review, naked plasmid delivery, or the delivery of complexed plasmids, and cell-mediated gene delivery to the myocardium will be reviewed. Pre-clinical and clinical trials in the cardiac tissue will form the core of the discussion. While unmodified stem cells are sometimes considered therapeutic vectors on the basis of paracrine mechanisms of action basic understanding is limited. Thus, only genetically modified cells will be discussed as cell-mediated gene therapy.

Transbronchial human interleukin-10 gene transfer reduces acute inflammation associated with allograft rejection and intragraft interleukin-2 and tumor necrosis factor-alpha gene expression in a rat model of lung transplantation

BACKGROUND

The ability to express genes with potential immunoregulatory capacity could reduce allograft rejection (AR). This study examined the effect of ex vivo lipid-mediated transbronchial human interleukin-10 (hIL-10) gene transfer on AR and the intragraft cytokine profile in a rat model of lung transplantation.

METHODS

Left single lung transplants were performed between a highly histoincompatible combination of inbred rats. The donor left lung was extracted and intrabronchially instilled with a plasmid encoding hIL-10 (IL-10 group) or Escherichia coli beta-galactosidase (control group), mixed with a cationic lipid. At 3 and 6 days after transplantation, the degree of AR was graded histologically (stage 1-4) and several pathologic categories of inflammation were scored on a scale of 0 to 4 according to the percentage of involvement. Intragraft cytokine profile was examined by real-time reverse transcription polymerase chain reaction.

RESULTS

The stage of AR (3.1 +/- 0.4 vs 3.8 +/- 0.4) and the pathologic scores for edema (2.3 +/- 0.8 vs 3.2 +/- 0.4), intraalveolar hemorrhage (0.3 +/- 0.5 vs 2.2 +/- 0.8), and necrosis (0.3 +/- 0.5 vs 1.2 +/- 0.4) in the IL-10 group were significantly decreased compared with the control group at Day 6. IL-2 and tumor necrosis factor-alpha messenger RNA expression levels on Day 3 were significantly decreased in the IL-10 group.

CONCLUSIONS

Ex vivo lipid-mediated transbronchial hIL-10 gene transfer attenuated acute inflammation associated with AR, which was related to decreased levels of proinflammatory cytokine gene expression in a rat model of lung transplantation.

Lipid-Mediated Transbronchial Human Interleukin-10 Gene Transfer Decreases Acute Inflammation Associated With Allograft Rejection in a Rat Model of Lung Transplantation

BACKGROUND

Transferring genes with immunoregulatory capacity to transplanted organs has the potential to modify allograft rejection (AR). We examined the effect of ex vivo lipid-mediated transbronchial human interleukin-10 (hIL-10) gene transfer on acute AR in a rat model of lung transplantation.

METHODS

Left single lung transplantations were performed between a highly histoincompatible rat combination: Brown Norway to Lewis. The extracted donor left lung was intrabronchially instilled with a plasmid encoding hIL-10 or Escherichia coli beta-galactosidase (control), mixed with a cationic lipid. On day 6 posttransplantation, the degree of AR was graded histologically (stages 1-4) based upon pathological categories of inflammation: perivascular, peribronchial, and peribronchiolar lymphocytic infiltrates, edema, intraalveolar hemorrhage, and necrosis.

RESULTS

The stage of AR in the IL-10 group (3.1 +/- 0.4) was significantly lower than the control group (3.8 +/- 0.4). Pathological scores for edema, intraalveolar hemorrhage, and necrosis in the IL-10 group (2.3 +/- 0.8, 0.3 +/- 0.5, and 0.3 +/- 0.5, respectively) were also significantly decreased compared with those in the control group (3.2 +/- 0.4, 2.2 +/- 0.8, and 1.2 +/- 0.4, respectively).

CONCLUSION

Ex vivo lipid-mediated transbronchial hIL-10 gene transfer attenuated acute inflammation associated with AR in a rat model of lung transplantation.