Enhanced survival of hypoimmunogenic otic progenitors following intracochlear xenotransplantation: repercussions for stem cell therapy in hearing loss models

Abstract

Stem cell replacement holds the potential for sensorineural hearing loss (SNHL) treatment. However, its translation into clinical practice requires strategies for improving stem cell survival following intracochlear transplantation. Considering recent findings showing that the inner ear contains a resident population of immune cells, we hypothesized that immune evasion would improve the survival and residence time of transplanted stem cells in the cochlea, potentially leading to better outcomes. To test this, we leveraged genetic engineering techniques to develop hypoimmunogenic human-induced pluripotent stem cells (hi-iPSC), which lack human leukocyte antigen expression. We found that gene editing does not affect the biological properties of hi-iPSCs, including their capacity to differentiate into otic neural progenitors (ONPs). Compared to wild-type ONPs, more hypoimmunogenic ONPs (derived from hi-iPSCs) were found in the inner ear of immunocompetent mice ten days following cochlear xenotransplantation. This approach may open a new avenue for experimental and clinical SNHL treatments.

Hypoimmunogenic human iPSCs expressing HLA-G, PD-L1, and PD-L2 evade innate and adaptive immunity

“…These results demonstrate that HyPSCs can differentiate into functional endothelial cells and hepatocytes. In addition to this, the differentiation of HyPSCs into otic progenitor cells has been reported [ 39 ].

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Recent Therapeutic Progress and Future Perspectives for the Treatment of Hearing Loss

“…A major obstacle for cell replacement therapy is evading the immune response when grafting cells. One strategy for overcoming this was presented by Andrade da Silva et al [169], who used genetic modification in human iPSCs. The human leukocyte antigen genes, which have the most significant effect on graft rejection, were knocked out using CRISPR-Cas9 to reduce immunogenicity when delivering two dimensional-differentiated otic neural progenitor cells into immunocompetent mouse cochlea.…”

Challenges of CRISPR/Cas-Based Cell Therapy for Type 1 Diabetes: How Not to Engineer a “Trojan Horse”

“…Another strategy to control Cas9-induced off-targets is to use its high-fidelity variants. However, in the case of iPSCs, only a small number of studies utilize Cas9 variants with increased specificity (Table 3), such as Hi-Fi Cas9 [128,176,184,185], also in one of the papers the authors used Cas9n nickase [111], a known high-fidelity Cas9 modification [186]. Lamothe at al., in their work, demonstrated the successful use of novel CRISPR-editing systems based on modified type II and type V nucleases for the genetic engineering of primary immune cells and iPSCs [187].…”

“…In addition to the introduction of knockouts of various genes, the genetic engineering of hypoimmunogenic cells involves the introduction of various knockins. The efficient insertion and expression of transgenes is achieved using different approaches: lentiviral particle [117,231], transposon [176], recombining AAV [114], and CRISPR/Cas9 [121,128,169]. The main loci for transgene insertion in the creation of hypoimmunogenic cells are AAVS1 [116,121,172] and GAPDH [128] (Table 3).…”