Gene therapy using non-viral peptide vector in a canine systemic lupus erythematosus model

Therapeutic effects of CTLA4Ig gene-transduced adipose tissue-derived mesenchymal stem cell transplantation on established autoimmune thyroiditis

This study aimed to identify the beneficial effects of adipose tissue-derived mesenchymal stem cells (ASCs) and ASCs that overexpress the CTLA4Ig gene (CTLA4Ig-ASCs) on established autoimmune thyroiditis and to examine changes in clinical chemistry parameters and the presence of humoral responses upon repeated long-term administration of autologous ASCs. This study also aimed to acquire desirable results in a preclinical study by using large-sized lab animals and applying ASCs that overexpress therapeutic genes. Experimental autoimmune thyroiditis was induced by immunization with thyroglobulin. Experimental dogs were divided into five groups: (i) ASC IT + IV, (ii) ASC IV, (iii) CTLA4Ig-ASC IT + IV, (iv) CTLA4Ig-ASC IV, and (v) control IT + IV (saline only), and they received intrathyroidal (IT; 10 million cells/250 µl saline per thyroid) administration one time or intravenous (IV; 20 million cells/5 ml) administration seven times within a 101-day period. Blood samples were collected every week, and thyroids were harvested on days 104-106. After serial ASC or CTLA4Ig transplantation, the levels of canine thyroglobulin autoantibodies (TgAA) in serum and the infiltration of T-lymphocytes between the follicles of the thyroid glands were decreased. The expression of FoxP3 in submandibular lymph nodes was significantly increased. Repeated long-term administration of autologous ASCs or CTLA4Ig-ASCs did not generate changes in clinical chemistry parameters or humoral responses.The TgAA test can detect autoimmune thyroiditis years before clinical signs of hypothyroidism occur. Thus, ASC and CTLA4Ig-ASC transplantation in that period can be attractive candidates to ameliorate autoimmune thyroiditis and prevent the development of hypothyroidism.

Adult stem cell therapy for autoimmune disease

Many studies of autologous hematopoietic stem cell transplantation (HSCT) and allogeneic HSCT have been conducted for autoimmune disease in various animal models. Because of the substantial risk of morbidity and mortality associated with allogeneic bone marrow transplantation, autologous transplants justified trying this approach in patient with severe autoimmune disease who were refractory to current treatments. Remission was achieved in some of the patients and some of them relapsed. Recently, many in vitro studies have reported that mesenchymal stem cells (MSC) have immunomodulatory properties and immunosuppressive effects on MHC-mismatched lymphocytes proliferation by inhibiting naïve, memory and activated T cells, B cell, NK cells and dendritic cells. In addition, adipose tissue-derived MSC (AT-MSC) are becoming an alternative source of MSC for therapeutic applications because adipose tissues are abundant, easily accessible, easily obtainable with little patient discomfort and large amounts of AT-MSC can be easily obtained. A large body of in vitro research has shown that AT-MSC have same or similar immunomodulatory effects with bone marrow derived MSC. Drawing on this finding, the increasing numbers of researchers have turned on their attention to preclinical studies on AT-MSC. As this new path of research evolves with subsequent reports, MSC would make a significant contribution to stem cell therapy or combination therapy for ameliorating symptoms and curing autoimmune disease. By searching and studying the appropriate therapeutic gene, the therapeutic gene transfected stem cell therapy will be able to acquire the synergy effect and the combined advantage of gene therapy and stem cell therapy.

The effect of gene therapy using CTLA4Ig/silica-nanoparticles on canine experimental autoimmune thyroiditis

BACKGROUND

The present study aimed to determine the effect of canine CTLA4Ig on canine autoimmune thyroiditis. In a previous study, we established a canine model of autoimmune thyroiditis by immunizing normal dogs with bovine thyroglobulin. An in vitro study using recombinant CTLA4Ig revealed that this protein can inhibit the expression of Th1-type cytokines and the pro-inflammatory cytokines tested.

METHODS

As a result of the in vitro study, we constructed therapeutic CTLA4Ig/silica-nanoparticles and applied them to the treatment of experimentally induced canine autoimmune thyroiditis.

RESULTS

Gene therapy resulted in significant reductions in anti-canine-thyroglobulin autoantibody titer, anti-T4 antibody titer and T-cell proliferation against thyroglobulin and in the mRNA expressions of interleukin-18 in fresh peripheral blood mononuclear cells (PBMC) from all dogs. There was also a significant reduction compared to day 0 in tumor necrosis factor-alpha and interferon-gamma levels in the supernatant from cultured PBMC.

CONCLUSIONS

The CTLA4Ig-induced suppression of Th1 cytokines is relatively more significant than it appears because autoimmune thyroiditis is a Th1-polarized disease. Thus, CTLA4Ig can improve Th1/Th2 cytokine balance in autoimmune thyroiditis by downregulating Th1 cytokines.

Preventive and therapeutic effects of gene therapy using silica nanoparticles-binding of GM-CSF gene on white blood cell production in dogs with leukopenia

OBJECTIVE

Our previous study has shown that granulocyte-macrophage colony-stimulating factor (GM-CSF) gene/silica nanoparticles have a leukocytosis effect in normal dogs. Therefore, this study was conducted to determine whether treatment of canine GM-CSF gene/silica nanoparticles has preventive or therapeutic effects in dogs with leukopenia.

MATERIALS AND METHODS

To induce leukopenia, vinblastine was administered intravenously at a dose of 2 mg/m(2) of body surface area on day 0. Then 7.5 microg GM-CSF/nanoparticles (1:100, w/w) were administered intravenously to each of four dogs in the prevention group on day 2 and an equivalent amount of GM-CSF/nanoparticles was administered to the post-nadir group on day 4 (other groups were administered phosphate-buffered saline intravenously).

RESULTS

Therapeutic GM-CSF gene was expressed in peripheral blood mononuclear cells for 10 days and both the prevention and post-nadir groups showed significant increases in white blood cell counts when compared with the control group, as confirmed by complete blood count, differential count, and flow cytometry.

CONCLUSIONS

GM-CSF/nanoparticles can be useful for correction of acute leukopenia, such as chemotherapy-induced myelosuppression, without developing neutralizing antibodies.

Cloning, expression and bioassay of canine CTLA4Ig

Blockade of the B7:CD28 costimulatory pathway has been shown to inhibit humoral immunity, graft rejection, graft versus host disease and ameliorate autoimmune diseases. A soluble chimeric fusion protein, CTLA4Ig, binds to B7 with greater affinity than CD28 and blocks the binding of CD28 to B7. We describe the cloning and expression of canine CTLA4Ig, a recombinant chimeric fusion protein composed of the extracellular domain of canine CTLA-4 and the CH2-CH3 domains of canine immunoglobulin alpha constant region (IGHA) genes, linked via an immunologically inert flexible peptide. The recombinant CTLA4Ig protein of approximately 45kDa molecular weight was expressed mainly as insoluble inclusion bodies in Escherichia coli. The protein was solubilized in denaturing buffer and purified using nickel-nitrilotriacetic acid (Ni-NTA) affinity column chromatography followed by refolding. The yield was about 6mg of recombinant CTLA4Ig per liter of culture. The purified protein was biologically active in one-way mixed lymphocyte reactions, demonstrating immunosuppressive activities in a dose-dependent manner. The findings suggest that recombinant canine CTLA4Ig protein could be valuable in assessing the function of CTLA-4 in the canine immune system and may be effective in autoimmune disease therapy.

Recent Advances in Small Animal Genetics

The whole genome sequence of the dog is complete, and partial sequencing of the cat genome is underway. Sequences allow the molecular basis for inherited diseases to be more easily determined, leading to development of DNA tests to verify carrier and affected states as well as potential gene therapy for the treatment of those diseases. To help veterinarians provide genetic services to their clients, the molecular genetic tests currently available are listed in this article. In addition, cloning of small animals is now available to clients on a commercial basis. Information about the cloning process and possible health issues in clones are discussed.