BMP Signaling Alleviates Allergic Airway Inflammation by Controlling Group 2 Innate Lymphoid Cells Homeostasis

Area of Science:

• Immunology
• Cell Biology
• Respiratory Medicine

Background:

• Bone morphogenetic proteins (BMPs) are increasingly recognized for their role in immunoregulation.
• Expression of BMP receptors on lymphoid progenitors and group 2 innate lymphoid cells (ILC2s) suggests a role in immune cell development.
• The specific function of BMP signaling in ILC2 development and activity, particularly in lung inflammation, is not well understood.

Purpose of the Study:

• To investigate the role of BMP signaling in the generation and effector functions of ILC2s during lung airway inflammation.
• To determine if BMP signaling influences ILC2 homeostasis and allergic responses in the airways.

Main Methods:

• Generation of BMP receptor 2 (BMPR2) conditional knockout (CKO) mice to study ILC2 development and function.
• Analysis of ILC2 numbers, proliferation, and effector functions in steady-state and papain-induced allergic airway inflammation models.
• In vitro and in vivo experiments using BMP4 to assess its effects on ILC2 proliferation and airway inflammation.

Main Results:

• BMPR2 deficiency in mice resulted in increased ILC2 numbers in the lungs, driven by enhanced cell proliferation.
• BMPR2 deficiency aggravated the early type 2 immune response in a papain-induced allergic airway inflammation model.
• BMP4 inhibited ILC2 proliferation via the canonical BMP signaling pathway, alleviating airway inflammation in control mice but not in BMPR2 CKO mice.

Conclusions:

• BMP signaling is a critical regulator of ILC2 homeostasis.
• Targeting BMP signaling may offer a therapeutic strategy for allergic airway inflammation by modulating ILC2 activity.