Canonical signaling by TGF family members in mesenchymal stromal cells is dispensable for hematopoietic niche maintenance under basal and stress conditions

PLoS One. 2020 May 29;15(5):e0233751. doi: 10.1371/journal.pone.0233751. eCollection 2020.

Abstract

Mesenchymal stromal cells are an important component of the bone marrow hematopoietic niche. Prior studies showed that signaling from members of the transforming growth factor (TGF) superfamily in mesenchymal stromal cells is required for normal niche development. Here, we assessed the impact of TGF family signaling on niche maintenance and stress responses by deleting Smad4 in mesenchymal stromal cells at birth, thereby abrogating canonical TGF signaling. No alteration in the number or spatial organization of CXCL12-abundant reticular (CAR) cells, osteoblasts, or adipocytes was observed in Osx-Cre, Smad4fl/fl mice, and expression of key niche factors was normal. Basal hematopoiesis and stress erythropoiesis responses to acute hemolytic anemia were normal. TGF-β potently inhibits stromal CXCL12 expression in vitro; however, G-CSF induced decreases in bone marrow CXCL12 expression and subsequent hematopoietic stem/progenitor cell mobilization were normal in Osx-Cre, Tgfbr2fl/fl mice, in which all TGF-β signaling in mesenchymal stromal is lost. Finally, although a prior study showed that TGF-β enhances recovery from myeloablative therapy, hematopoietic recovery following single or multiple doses of 5-flurauracil were normal in Osx-Cre, Tgfbr2fl/fl mice. Collectively, these data suggest that TGF family member signaling in mesenchymal stromal cells is dispensable for hematopoietic niche maintenance under basal and stress conditions.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Acute Disease
  • Anemia, Hemolytic / metabolism*
  • Anemia, Hemolytic / pathology
  • Animals
  • Bone Marrow / metabolism
  • Bone Marrow / pathology
  • Cells, Cultured
  • Chemokine CXCL12 / metabolism
  • Erythropoiesis*
  • Female
  • Granulocyte Colony-Stimulating Factor / pharmacology
  • Hematopoietic Stem Cell Mobilization
  • Hematopoietic Stem Cells* / cytology
  • Hematopoietic Stem Cells* / pathology
  • Male
  • Mesenchymal Stem Cells* / cytology
  • Mesenchymal Stem Cells* / pathology
  • Mice
  • Mice, Inbred C57BL
  • Stem Cell Niche
  • Transforming Growth Factor beta / physiology*
  • Transforming Growth Factors / physiology*

Substances

  • Chemokine CXCL12
  • Cxcl12 protein, mouse
  • Transforming Growth Factor beta
  • Granulocyte Colony-Stimulating Factor
  • Transforming Growth Factors