Reprogramming of the MHC‐I and Its Regulation by NFκB in Human‐Induced Pluripotent Stem Cells

Abstract

The immunogenicity of human pluripotent stem cells plays a major role in their potential use in the clinic. We show that, during their reprogramming, human-induced pluripotent stem (iPS) cells downregulate expression of human leukocyte antigen (HLA)-A/B/C and b2 microglobulin (b2M), the two components of major histocompatibility complex-I (MHC-I). MHC-I expression in iPS cells can be restored by differentiation or treatment with interferongamma (IFNc). To analyze the molecular mechanisms that regulate the expression of the MHC-I molecules in human iPS cells, we searched for correlation between the expression of HLA-A/B/C and b2M and the expression of transcription factors that bind to the promoter of these genes. Our results show a significant positive correlation between MHC-I expression and expression of the nuclear factors, nuclear factor kappa B 1 (NFjB1) and RelA, at the levels of RNA, protein and was confirmed by chromatin binding. Concordantly, we detected robust levels of NFjB1 and RelA proteins in the nucleus of somatic cells but not in the iPS cell derived from them. Overexpression of NFjB1 and RelA in undifferentiated pluripotent stem cells led to induction in expression of MHC-I, whereas silencing NFjB1 and RelA by small hairpin RNA decreased the expression of b2M after IFNc treatment. Our data point to the critical role of NFjB proteins in regulating the MHC-I expression in human pluripotent stem cells. STEM

Low Immunogenicity of Neural Progenitor Cells Differentiated from Induced Pluripotent Stem Cells Derived from Less Immunogenic Somatic Cells

“…Recent research indicated a significant positive correlation between MHC-I and the nuclear factors, NFκB1 and RelA, pointing to the critical role of NFκB proteins in regulating the MHC-I expression in human iPS cells [34]. In their study, Pick and colleagues reported that over-expression of NFκB1 and RelA in undifferentiated iPS cells could lead to induction of MHC-I expression and silencing of NFκB1 and RelA by shRNA results in decreased expression of β-2M after IFN-γ treatment.…”

“…Nevertheless, it is entirely possible that this immunogenicity could further increase during differentiation to specific tissues, as has been observed during differentiation of ES cells with increasing expression of HLA [30]–[33]. A recent study has demonstrated that upregulated expression of NFκB1 and RelA, two members of NFκB family during cell reprogramming, could increase the expression of HLA-I in iPS cells [34]. Suárez -Alvarez et al have shown that revealed HLA-B and β-2M can activate the transporter associated with antigen processing and can thus increase immunogenicity through induction of H3K4me3 modification during the differentiation [35].…”

“…From a practical point of view, the autologous derivation of iPS cells would require a lot of time and cost for assessment of their medical stability, safety, and efficacy [30], [34], [38]. Thus, generation of universal donor cells was raised as another hope for regenerative medicine [34], [38], [39].…”

“…Thus, generation of universal donor cells was raised as another hope for regenerative medicine [34], [38], [39]. For example, the umbilical cord is extra-embryonic tissue of particular interest for regenerative medicine [12], [15].…”

A practical guide to induced pluripotent stem cell research using patient samples

“…To circumvent this, commonly available iPSCs from healthy donors may be used for comparison. MRC5-derived (fetal lung fibroblast) iPSCs have been utilized as a control in several previous reports, 13,[37][38][39][40][41] and can be obtained from the public bank. If MRC5-iPSCs do not demonstrate pathogenic phenotypes that disease iPSCs do under the same experimental condition, MRC5-iPSCs would serve as a practical control.…”