NRF2-mediated Notch pathway activation enhances hematopoietic reconstitution following myelosuppressive radiation
Jung-Hyun Kim, … , Sanjay V. Malhotra, Shyam Biswal
Jung-Hyun Kim, … , Sanjay V. Malhotra, Shyam Biswal
Published January 27, 2014
Citation Information: J Clin Invest. 2014;124(2):730-741. https://doi.org/10.1172/JCI70812.
View: Text | PDF
Research Article

NRF2-mediated Notch pathway activation enhances hematopoietic reconstitution following myelosuppressive radiation

Abstract

A nuclear disaster may result in exposure to potentially lethal doses of ionizing radiation (IR). Hematopoietic acute radiation syndrome (H-ARS) is characterized by severe myelosuppression, which increases the risk of infection, bleeding, and mortality. Here, we determined that activation of nuclear factor erythroid-2–related factor 2 (NRF2) signaling enhances hematopoietic stem progenitor cell (HSPC) function and mitigates IR-induced myelosuppression and mortality. Augmenting NRF2 signaling in mice, either by genetic deletion of the NRF2 inhibitor Keap1 or by pharmacological NRF2 activation with 2-trifluoromethyl-2′-methoxychalone (TMC), enhanced hematopoietic reconstitution following bone marrow transplantation (BMT). Strikingly, even 24 hours after lethal IR exposure, oral administration of TMC mitigated myelosuppression and mortality in mice. Furthermore, TMC administration to irradiated transgenic Notch reporter mice revealed activation of Notch signaling in HSPCs and enhanced HSPC expansion by increasing Jagged1 expression in BM stromal cells. Administration of a Notch inhibitor ablated the effects of TMC on hematopoietic reconstitution. Taken together, we identified a mechanism by which NRF2-mediated Notch signaling improves HSPC function and myelosuppression following IR exposure. Our data indicate that targeting this pathway may provide a countermeasure against the damaging effects of IR exposure.

Authors

Jung-Hyun Kim, Rajesh K. Thimmulappa, Vineet Kumar, Wanchang Cui, Sarvesh Kumar, Ponvijay Kombairaju, Hao Zhang, Joseph Margolick, William Matsui, Thomas Macvittie, Sanjay V. Malhotra, Shyam Biswal

×

Figure 2

Augmenting NRF2 signaling enhances BM engraftment.

Options: View larger image (or click on image) Download as PowerPoint
Augmenting NRF2 signaling enhances BM engraftment. (A) Schematic of expe...
(A) Schematic of experiment depicted in B and C. Sorted LSK cells from poly(I:C)-treated MxCre-Keap1flox/flox or floxed controls were transplanted into recipient mice with 250,000 competitor cells. (B and C) Flow cytometric analysis (B) and percentage of donor cell in PB at 6, 8, and 14 weeks following BMT (C). (D) Schematic of experiment depicted in E and F. Mice were treated daily with poly(I:C) for 7 days after BMT. (E) Percentage of donor cells in PB following serial BMT (first and second BMT). (F) Donor-derived granulocyte (GR1+), B cell (B220+), and T cell (THY1.2+) lineages in PB of recipient mice after the second transplantation. (G) Schematic of ex vivo experiment depicted in H and I. BM stromal cells isolated from tamoxifen-treated CMVCre-Keap1flox/flox or floxed mice were plated as feeder cells. Five hundred sorted LSK cells were cocultured with BM stromal cells. LSK progeny cells harvested on day 7 were stained and analyzed. (H) Expression of Keap1, Nqo1, and Gclm genes in BM stromal cells (CD45–TER119–) isolated from CMVCre-Keap1–/– mice and floxed control mice. (I) Total number of LSK cells on day 7. (J and K) Percentage of donor cells (CD45.2) in the PB (J) and BM (LIN–) (K) of TMC- or vehicle-administered recipient mice (n = 10–15/group) after BMT. CD45.2 BM cells (500,000 cells) were transferred into irradiated recipient WT mice. The recipient mice were orally administered vehicle (Veh) or TMC 6 times, once every 48 hours, beginning 1 hour after BMT (n = 10–15/group). *P < 0.05, **P < 0.01, ***P < 0.001.