Selective deletion of SHIP-1 in hematopoietic cells in mice leads to severe lung inflammation involving ILC2 cells

Sci Rep. 2021 Apr 28;11(1):9220. doi: 10.1038/s41598-021-88677-8.

Abstract

Src homology 2 domain-containing inositol 5-phosphatase 1 (SHIP-1) regulates the intracellular levels of phosphotidylinositol-3, 4, 5-trisphosphate, a phosphoinositide 3-kinase (PI3K) product. Emerging evidence suggests that the PI3K pathway is involved in allergic inflammation in the lung. Germline or induced whole-body deletion of SHIP-1 in mice led to spontaneous type 2-dominated pulmonary inflammation, demonstrating that SHIP-1 is essential for lung homeostasis. However, the mechanisms by which SHIP-1 regulates lung inflammation and the responsible cell types are still unclear. Deletion of SHIP-1 selectively in B cells, T cells, dendritic cells (DC) or macrophages did not lead to spontaneous allergic inflammation in mice, suggesting that innate immune cells, particularly group 2 innate lymphoid cells (ILC2 cells) may play an important role in this process. We tested this idea using mice with deletion of SHIP-1 in the hematopoietic cell lineage and examined the changes in ILC2 cells. Conditional deletion of SHIP-1 in hematopoietic cells in Tek-Cre/SHIP-1 mice resulted in spontaneous pulmonary inflammation with features of type 2 immune responses and airway remodeling like those seen in mice with global deletion of SHIP-1. Furthermore, when compared to wild-type control mice, Tek-Cre/SHIP-1 mice displayed a significant increase in the number of IL-5/IL-13 producing ILC2 cells in the lung at baseline and after stimulation by allergen Papain. These findings provide some hints that PI3K signaling may play a role in ILC2 cell development at baseline and in response to allergen stimulation. SHIP-1 is required for maintaining lung homeostasis potentially by restraining ILC2 cells and type 2 inflammation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Fibrosis / etiology
  • Fibrosis / pathology*
  • Hematopoietic Stem Cells / metabolism
  • Hematopoietic Stem Cells / pathology*
  • Immunity, Innate / immunology
  • Lymphocytes / pathology*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Papain / toxicity
  • Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases / physiology*
  • Pneumonia / etiology
  • Pneumonia / pathology*

Substances

  • Inpp5d protein, mouse
  • Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases
  • Papain