Genetic and Small Molecule Disruption of the AID/RAD51 Axis Similarly Protects Nonobese Diabetic Mice from Type 1 Diabetes through Expansion of Regulatory B Lymphocytes

J Immunol. 2017 Jun 1;198(11):4255-4267. doi: 10.4049/jimmunol.1700024. Epub 2017 May 1.

Abstract

B lymphocytes play a key role in type 1 diabetes (T1D) development by serving as a subset of APCs preferentially supporting the expansion of autoreactive pathogenic T cells. As a result of their pathogenic importance, B lymphocyte-targeted therapies have received considerable interest as potential T1D interventions. Unfortunately, the B lymphocyte-directed T1D interventions tested to date failed to halt β cell demise. IgG autoantibodies marking humans at future risk for T1D indicate that B lymphocytes producing them have undergone the affinity-maturation processes of class switch recombination and, possibly, somatic hypermutation. This study found that CRISPR/Cas9-mediated ablation of the activation-induced cytidine deaminase gene required for class switch recombination/somatic hypermutation induction inhibits T1D development in the NOD mouse model. The activation-induced cytidine deaminase protein induces genome-wide DNA breaks that, if not repaired through RAD51-mediated homologous recombination, result in B lymphocyte death. Treatment with the RAD51 inhibitor 4,4'-diisothiocyanatostilbene-2, 2'-disulfonic acid also strongly inhibited T1D development in NOD mice. The genetic and small molecule-targeting approaches expanded CD73+ B lymphocytes that exert regulatory activity suppressing diabetogenic T cell responses. Hence, an initial CRISPR/Cas9-mediated genetic modification approach has identified the AID/RAD51 axis as a target for a potentially clinically translatable pharmacological approach that can block T1D development by converting B lymphocytes to a disease-inhibitory CD73+ regulatory state.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / pharmacology
  • 5'-Nucleotidase / immunology
  • Animals
  • Autoantibodies / immunology
  • B-Lymphocytes, Regulatory / immunology*
  • CRISPR-Cas Systems
  • Carrier Proteins / antagonists & inhibitors*
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism
  • Cytidine Deaminase / antagonists & inhibitors*
  • Cytidine Deaminase / genetics
  • Cytidine Deaminase / metabolism
  • Diabetes Mellitus, Experimental
  • Diabetes Mellitus, Type 1 / immunology*
  • Diabetes Mellitus, Type 1 / prevention & control*
  • Immunoglobulin Class Switching
  • Lymphocyte Activation*
  • Mice
  • Mice, Inbred NOD
  • Nuclear Proteins / antagonists & inhibitors*
  • Nuclear Proteins / deficiency
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism
  • Somatic Hypermutation, Immunoglobulin

Substances

  • Autoantibodies
  • Carrier Proteins
  • Nuclear Proteins
  • Rad51ap1 protein, mouse
  • 5'-Nucleotidase
  • AICDA (activation-induced cytidine deaminase)
  • Cytidine Deaminase
  • 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid