Mesenchymal stem cells promote the sustained expression of CD69 on activated T lymphocytes: roles of canonical and non-canonical NF-?B signalling.
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ABSTRACT: Mesenchymal stem cells (MSCs) are known to induce the conversion of activated T cells into regulatory T cells in vitro. The marker CD69 is a target of canonical nuclear factor kappa-B (NF-?B) signalling and is transiently expressed upon activation; however, stable CD69 expression defines cells with immunoregulatory properties. Given its enormous therapeutic potential, we explored the molecular mechanisms underlying the induction of regulatory cells by MSCs. Peripheral blood CD3(+) T cells were activated and cultured in the presence or absence of MSCs. CD4(+) cell mRNA expression was then characterized by microarray analysis. The drug BAY11-7082 (BAY) and a siRNA against v-rel reticuloendotheliosis viral oncogene homolog B (RELB) were used to explore the differential roles of canonical and non-canonical NF-?B signalling, respectively. Flow cytometry and real-time PCR were used for analyses. Genes with immunoregulatory functions, CD69 and non-canonical NF-?B subunits (RELB and NFKB2) were all expressed at higher levels in lymphocytes co-cultured with MSCs. The frequency of CD69(+) cells among lymphocytes cultured alone progressively decreased after activation. In contrast, the frequency of CD69(+) cells increased significantly following activation in lymphocytes co-cultured with MSCs. Inhibition of canonical NF-?B signalling by BAY immediately following activation blocked the induction of CD69; however, inhibition of canonical NF-?B signalling on the third day further induced the expression of CD69. Furthermore, late expression of CD69 was inhibited by RELB siRNA. These results indicate that the canonical NF-?B pathway controls the early expression of CD69 after activation; however, in an immunoregulatory context, late and sustained CD69 expression is promoted by the non-canonical pathway and is inhibited by canonical NF-?B signalling.
SUBMITTER: Saldanha-Araujo F
PROVIDER: S-EPMC3823077 | biostudies-literature | 2012 Jun
REPOSITORIES: biostudies-literature
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