Mesenchymal Stem Cells Do Not Prevent Antibody Responses against Human α-L-Iduronidase when Used to Treat Mucopolysaccharidosis Type I

Abstract

Mucopolysaccharidosis type I (MPSI) is an autosomal recessive disease that leads to systemic lysosomal storage, which is caused by the absence of α-L-iduronidase (IDUA). Enzyme replacement therapy is recognized as the best therapeutic option for MPSI; however, high titers of anti-IDUA antibody have frequently been observed. Due to the immunosuppressant properties of MSC, we hypothesized that MSC modified with the IDUA gene would be able to produce IDUA for a long period of time. Sleeping Beauty transposon vectors were used to modify MSC because these are basically less-immunogenic plasmids. For cell transplantation, 4×106 MSC-KO-IDUA cells (MSC from KO mice modified with IDUA) were injected into the peritoneum of KO-mice three times over intervals of more than one month. The total IDUA activities from MSC-KO-IDUA before cell transplantation were 9.6, 120 and 179 U for the first, second and third injections, respectively. Only after the second cell transplantation, more than one unit of IDUA activity was detected in the blood of 3 mice for 2 days. After the third cell transplantation, a high titer of anti-IDUA antibody was detected in all of the treated mice. Anti-IDUA antibody response was also detected in C57Bl/6 mice treated with MSC-WT-IDUA. The antibody titers were high and comparable to mice that were immunized by electroporation. MSC-transplanted mice had high levels of TNF-alpha and infiltrates in the renal glomeruli. The spreading of the transplanted MSC into the peritoneum of other organs was confirmed after injection of 111In-labeled MSC. In conclusion, the antibody response against IDUA could not be avoided by MSC. On the contrary, these cells worked as an adjuvant that favored IDUA immunization. Therefore, the humoral immunosuppressant property of MSC is questionable and indicates the danger of using MSC as a source for the production of exogenous proteins to treat monogenic diseases.

An Efficient Electroporation Protocol for the Genetic Modification of Mammalian Cells

“…Long-term expression of the transgene can be potentially increased by the use of SB100× RNA, decreasing the toxicity of the electroporation process as reported (Peng et al, 2009), or by carefully titrating the transposase plasmid mass to avoid overproduction inhibition (Grabundzija et al, 2010). These vectors and others recently reported in the literature (Kowarz et al, 2015), in conjunction with Chicabuffers, could be potentially used in diverse experimental gene therapy approaches, such as T cell immunotherapy (Singh et al, 2015), MSCs (Martin et al, 2014), and stem cell gene therapy protocols (Aiuti et al, 2013), further facilitating the application of these technologies in basic, translational, and clinical studies.…”

An efficient electroporation protocol for the genetic modification of mammalian cells

“…Long-term expression of the transgene can be potentially increased by the use of SB100x RNA, decreasing the toxicity of the electroporation process as reported (Peng et al, 2009), or by carefully titrating the transposase plasmid mass to avoid overproduction inhibition (Grabundzija et al, 2010). These vectors and others recently reported in the literature (Kowarz et al, 2015), in conjunction with Chicabuffers, could be potentially used in diverse experimental gene therapy approaches, such as T cell immunotherapy (Singh et al, 2015), MSC (Martin et al, 2014) and stem cell gene therapy protocols (Aiuti et al, 2013), further facilitating the application of these technologies in basic, translational and clinical studies.…”

α-l-iduronidase gene-based therapy using the phiC31 system to treat mucopolysaccharidose type I mice

“…This indicates a relevant antigenic property of human IDUA, which is likely responsible for the elimination or neutralization of IDUA. In our experience, we have used mesenchymal stem cells (MSC) as a vehicle to express IDUA in IDUA –/– mice because these cells have strong immunosuppressant properties . However, even in the presence of MSC, the immune response against IDUA could not be avoided and exogenous IDUA gene expression stopped soon after its administration.…”