Impact of C-rel inhibition of cord blood-derived B-, T-, and NK cells

J Immunotoxicol. 2017 Dec;14(1):15-22. doi: 10.1080/1547691X.2016.1250849. Epub 2017 Jan 16.

Abstract

The c-Rel transcription factor is a unique member of the nuclear factor (NF)-κB family that has a role in curtailing the proliferation, differentiation, cytokine production, and overall activity of B- and T-cells. In addition, c-Rel is a key regulator of apoptosis in that it influences the expression of anti-apoptotic genes such as Bcl-2 and Bcl-xL; conversely, inhibition of c-Rel increases cell apoptosis. To better understand the relationship between c-Rel expression and effects on B- and T-cell expansion, the current study evaluated c-Rel expression in cord blood mononuclear cells. This particular source was selected as cord blood is an important source of cells used for transplantation and immunotherapy, primarily in treating leukemias. As stem cell factor (SCF) and FLT3 are important agents for hematopoietic stem cell expansion, and cytokines like interleukin (IL)-2, -7, and -15 are essential for T- and B- (and also NK) cell development and proliferation, the current study evaluated c-Rel expression in cord blood mononuclear cells and CD34+ cells, as well as effects on B-, T-, and NK cells associated with alterations in c-Rel expression, using flow cytometry and PCR. The results showed c-Rel expression increased among cells cultured in the presence of SCF and FLT3 but was reduced when IL-2, IL-7, and IL-15 were used all together. Further, inhibition of c-Rel expression by siRNA reduced cord blood-derived B-, T-, and NK cell differentiation and expansion. These results indicated that with cells isolated from cord blood, c-Rel has an important role in B-, T-, and NK cell differentiation and, further, that agents (select cytokines/growth factors) that could impact on its expression might not only affect immune cell profiles in a host but could potentially also limit apoptotic activities in (non-)immune cells in that host. In the context of cancer (immuno)therapy, in particular, when cord blood is used an important source in stem cell transplantation in leukemia patients, such down-regulating changes in c-Rel levels could be counter-productive.

Keywords: CD34+ cells; FLT3; NF-κB; c-Rel; cord blood; cytokines; siRNA; stem cell factor (SCF).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis
  • B-Lymphocytes / immunology*
  • B-Lymphocytes / transplantation
  • Cell Differentiation
  • Cell Proliferation
  • Cells, Cultured
  • Cytokines / metabolism
  • Fetal Blood / cytology
  • Hematopoietic Stem Cell Transplantation*
  • Humans
  • Immunotherapy / methods*
  • Killer Cells, Natural / immunology*
  • Killer Cells, Natural / transplantation
  • Leukemia / immunology
  • Leukemia / therapy*
  • Proto-Oncogene Proteins c-rel / genetics
  • Proto-Oncogene Proteins c-rel / metabolism*
  • RNA, Small Interfering / genetics
  • Stem Cell Factor / metabolism
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / transplantation
  • Transcriptional Activation
  • fms-Like Tyrosine Kinase 3 / metabolism

Substances

  • Cytokines
  • Proto-Oncogene Proteins c-rel
  • RNA, Small Interfering
  • Stem Cell Factor
  • FLT3 protein, human
  • fms-Like Tyrosine Kinase 3