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Media type:
E-Article
Title:
Reprogramming IgH isotype-switched B cells to functional-grade induced pluripotent stem cells
Contributor:
Wesemann, Duane R.;
Portuguese, Andrew J.;
Magee, Jennifer M.;
Gallagher, Michael P.;
Zhou, Xiaolong;
Panchakshari, Rohit A.;
Alt, Frederick W.
imprint:
Proceedings of the National Academy of Sciences, 2012
Published in:Proceedings of the National Academy of Sciences
Language:
English
DOI:
10.1073/pnas.1210286109
ISSN:
0027-8424;
1091-6490
Origination:
Footnote:
Description:
<jats:p>Induced pluripotent stem cells (iPSCs) can be formed from somatic cells by a defined set of genetic factors; however, aberrant epigenetic silencing of the imprinted<jats:italic>Dlk1-Dio3</jats:italic>gene cluster often hinders their developmental potency and ability to contribute to high-grade chimerism in mice. Here, we describe an approach that allows splenic B cells activated to undergo Ig heavy-chain (<jats:italic>IgH</jats:italic>) class-switch recombination (CSR) to be reprogrammed into iPSCs that contribute to high-grade chimerism in mice. Treatment of naïve splenic B cells in culture with anti-CD40 plus IL-4 induces<jats:italic>IgH</jats:italic>CSR from IgM to IgG1 and IgE. CSR leads to irreversible<jats:italic>IgH</jats:italic>locus deletions wherein the IgM-producing Cμ exons are permanently excised from the B-cell genome. We find that anti-CD40 plus IL-4–activated B cells produce iPSCs that are uniformly hypermethylated in the imprinted<jats:italic>Dlk1-Dio3</jats:italic>gene cluster and fail to produce chimerism in mice. However, treatment of activated B cells with the methyltransferase inhibitor 5-aza-2′-deoxycytidine before and at early stages of reprogramming attenuates hypermethylation of the<jats:italic>Dlk1-Dio3</jats:italic>locus in resultant iPSCs and enables them to form high-grade chimerism in mice. These conditions allowed us to produce chimeric mice in which all mature B cells were derived entirely from IgG1-expressing B-cell–derived iPSCs. We conclude that culture conditions of activated B cells before and at early stages of reprogramming influence the developmental potency of resultant iPSCs.</jats:p>