Calmodulin inhibitors improve erythropoiesis in Diamond-Blackfan anemia

Alison M Taylor1,2,3, Elizabeth R Macari1,2,3, Iris T Chan1,2, Megan C Blair1,2, Sergei Doulatov1,2,3, Linda T Vo1,2,3, David M Raiser2,3,4, Kavitha Siva5, Anindita Basak2,3,6, Mehdi Pirouz1,2,3, Arish N Shah7, Katherine McGrath1,2, Jessica M Humphries1,2, Emma Stillman1,2, Blanche P Alter8, Eliezer Calo7, Richard I Gregory1,2,3, Vijay G Sankaran2,3,6, Johan Flygare5, Benjamin L Ebert2,3,6, Yi Zhou1,2, George Q Daley1,2,3, Leonard I Zon9,2,3,10,11

  1. Stem Cell Program, Boston Children's Hospital and Harvard Stem Cell Institute, Boston, MA 02115, USA.
  2. Division of Hematology/Oncology, Boston Children's Hospital and Dana Farber Cancer Institute, Boston, MA 02115, USA.
  3. Harvard Medical School, Boston, MA 02115, USA.
  4. Division of Hematology, Brigham and Women's Hospital, Boston, MA 02115, USA.
  5. Stem Cell Center, Lund University, Lund 22184, Sweden.
  6. Broad Institute of MIT and Harvard, Cambridge, MA 02139, USA.
  7. MIT Department of Biology and David H. Koch Institute for Integrative Cancer Research, Cambridge, MA 02139, USA.
  8. Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Rockville, MD 20850, USA.
  9. Stem Cell Program, Boston Children's Hospital and Harvard Stem Cell Institute, Boston, MA 02115, USA. zon@enders.tch.harvard.edu.
  10. Howard Hughes Medical Institute, Boston, MA 02115, USA.
  11. Stem Cell and Regenerative Biology Department, Harvard University, Boston, MA 02115, USA.

Abstract

Diamond-Blackfan anemia (DBA) is a rare hematopoietic disease characterized by a block in red cell differentiation. Most DBA cases are caused by mutations in ribosomal proteins and characterized by higher than normal activity of the tumor suppressor p53. Higher p53 activity is thought to contribute to DBA phenotypes by inducing apoptosis during red blood cell differentiation. Currently, there are few therapies available for patients with DBA. We performed a chemical screen using zebrafish ribosomal small subunit protein 29 (rps29) mutant embryos that have a p53-dependent anemia and identified calmodulin inhibitors that rescued the phenotype. Our studies demonstrated that calmodulin inhibitors attenuated p53 protein amount and activity. Treatment with calmodulin inhibitors led to decreased p53 translation and accumulation but does not affect p53 stability. A U.S. Food and Drug Administration-approved calmodulin inhibitor, trifluoperazine, rescued hematopoietic phenotypes of DBA models in vivo in zebrafish and mouse models. In addition, trifluoperazine rescued these phenotypes in human CD34+ hematopoietic stem and progenitor cells. Erythroid differentiation was also improved in CD34+ cells isolated from a patient with DBA. This work uncovers a potential avenue of therapeutic development for patients with DBA.

Presented By Alison Taylor | ORCID iD

Cell & Developmental Bio, MedicineNicholas Liao2020-10 (Oct)