Induction of the Hajdu-Cheney Syndrome Mutation in CD19 B Cells in Mice Alters B-Cell Allocation but Not Skeletal Homeostasis.

ABSTRACT: Mice harboring Notch2 mutations replicating Hajdu-Cheney syndrome (Notch2tm1.1ECan) have osteopenia and exhibit an increase in splenic marginal zone B cells with a decrease in follicular B cells. Whether the altered B-cell allocation is responsible for the osteopenia of Notch2tm1.1ECan mutants is unknown. To determine the effect of NOTCH2 activation in B cells on splenic B-cell allocation and skeletal phenotype, a conditional-by-inversion (COIN) Hajdu-Cheney syndrome allele of Notch2 (Notch2[?PEST]COIN) was used. Cre recombination generates a permanent Notch2?PEST allele expressing a transcript for which sequences coding for the proline, glutamic acid, serine, and threonine-rich (PEST) domain are replaced by a stop codon. CD19-Cre drivers were backcrossed into Notch2[?PEST]COIN/[?PEST]COIN to generate CD19-specific Notch2?PEST/?PEST mutants and control Notch2[?PEST]COIN/[?PEST]COIN littermates. There was an increase in marginal zone B cells and a decrease in follicular B cells in the spleen of CD19Cre/WT;Notch2?PEST/?PEST mice, recapitulating the splenic phenotype of Notch2tm1.1ECan mice. The effect was reproduced when the NOTCH1 intracellular domain was induced in CD19-expressing cells (CD19Cre/WT;RosaNotch1/WT mice). However, neither CD19Cre/WT;Notch2?PEST/?PEST nor CD19Cre/WT;RosaNotch1/WT mice had a skeletal phenotype. Moreover, splenectomies in Notch2tm1.1ECan mice did not reverse their osteopenic phenotype. In conclusion, Notch2 activation in CD19-expressing cells determines B-cell allocation in the spleen but has no skeletal consequences.

SUBMITTER: Yu J 

PROVIDER: S-EPMC5971225 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature