CD44 in Group 1 Innate Lymphoid Cells Impacts the Development and Progression of Steatohepatitis

Area of Science:

• Immunology
• Hepatology
• Cell Biology

Background:

• Innate lymphoid cells (ILCs) are crucial in liver inflammation and fibrosis, common in chronic liver diseases.
• The role of group 1 ILCs, including NK cells and ILC1s, in steatohepatitis and MASLD remains unclear.
• CD44, a cell surface molecule, is expressed by group 1 ILCs.

Purpose of the Study:

• To investigate the role of CD44 in group 1 ILCs during steatohepatitis and MASLD.
• To determine how CD44 deficiency in group 1 ILCs impacts liver inflammation and disease progression.

Main Methods:

• Engineered a mouse model with CD44-deficient group 1 ILCs.
• Challenged mice with diet-induced obesity, MASLD, or steatohepatitis.
• Conducted in vitro co-cultures of LPS-stimulated liver NK cells with hepatocytes and macrophages.

Main Results:

• CD44 deficiency in group 1 ILCs reduced hepatic NKp46+ ILCs, NK cells, and ILC1s.
• Absence of CD44 aggravated hepatic injury, inflammation, and fibrosis in MASLD and steatohepatitis models.
• CD44-deficient NK cells showed enhanced inflammatory responses, promoting pro-inflammatory mediator release from hepatocytes and macrophages.

Conclusions:

• CD44 plays a significant role in regulating group 1 ILC dynamics.
• CD44 influences the development and severity of steatohepatitis and MASLD.