Targeting antiapoptotic A1/Bfl-1 by in vivo RNAi reveals multiple roles in leukocyte development in mice

Blood. 2012 Jun 21;119(25):6032-42. doi: 10.1182/blood-2011-12-399089. Epub 2012 May 11.

Abstract

Gene-targeting studies in mice have identified the essential roles of most prosurvival Bcl-2 family members in normal physiology and under conditions of stress. The function of one member, Bcl2a1/Bfl-1/A1, is only poorly understood because of quadruplication of its gene locus in mice, hindering conventional knockout studies. To overcome this problem, we generated mouse models allowing traceable constitutive or reversible ablation of A1 in the hematopoietic system by RNA interference. Knockdown of A1 impaired early stages of T-cell differentiation, B-cell homeostasis, and sensitized transitional as well as follicular B cells to apoptosis induced by ligation of the B-cell receptor. As a consequence, B-cell proliferation in response to mitogens was severely impaired, whereas that of T cells appeared unaffected. Furthermore, depending on the extent of A1 knockdown, granulocytes showed increased spontaneous death in culture or failed to accumulate in significant numbers in vivo. These models highlight the critical role of A1 in leukocyte development and homeostasis, constituting valuable tools for investigating presumed roles of this Bcl-2 family member in immunity, tumorigenesis, and drug resistance.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis Regulatory Proteins / antagonists & inhibitors
  • Female
  • HEK293 Cells
  • Hematopoiesis / drug effects
  • Hematopoiesis / genetics*
  • Humans
  • Leukocytes / drug effects
  • Leukocytes / metabolism
  • Leukocytes / pathology
  • Leukocytes / physiology*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Inbred CBA
  • Mice, Transgenic
  • MicroRNAs / genetics
  • MicroRNAs / pharmacology
  • Minor Histocompatibility Antigens
  • Molecular Targeted Therapy / methods
  • Proto-Oncogene Proteins c-bcl-2 / antagonists & inhibitors
  • Proto-Oncogene Proteins c-bcl-2 / genetics*
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Proto-Oncogene Proteins c-bcl-2 / physiology*
  • RNA Interference* / physiology
  • RNA, Small Interfering / pharmacology

Substances

  • Apoptosis Regulatory Proteins
  • BCL2-related protein A1
  • MicroRNAs
  • Minor Histocompatibility Antigens
  • Mirn30d microRNA, mouse
  • Proto-Oncogene Proteins c-bcl-2
  • RNA, Small Interfering