Secreted Phosphoprotein 1 in Lung Diseases.

Area of Science:

• Pulmonary Medicine
• Immunology
• Cell Biology

Background:

• Secreted phosphoprotein 1 (SPP1), also known as osteopontin (OPN), is a key protein in immune modulation, stress response, and tissue remodeling.
• SPP1 expression is elevated in various interstitial lung diseases (ILDs), including idiopathic pulmonary fibrosis (IPF), and is associated with poor prognosis.
• SPP1's role extends to infectious lung diseases, malignancies, airway diseases, and COVID-19, highlighting its broad impact on respiratory health.

Purpose of the Study:

• To review the proposed mechanisms by which SPP1 contributes to lung disease development.
• To emphasize the role of SPP1 in interstitial lung diseases (ILDs).
• To highlight SPP1 as a potential therapeutic target for fibrotic lung diseases.

Main Methods:

• Literature review of studies investigating SPP1 in lung diseases.
• Analysis of data from single-cell RNA sequencing and clinical studies.
• Examination of SPP1 expression in various cell types involved in fibrogenesis.

Main Results:

• Elevated SPP1 levels in serum, bronchoalveolar lavage fluid, or lung tissue generally correlate with a poor prognosis in lung diseases.
• SPP1 is expressed in critical fibrogenic cells, including macrophages, epithelial cells, and fibroblasts.
• Recent single-cell RNA sequencing data underscore SPP1's significance in ILDs.

Conclusions:

• SPP1 plays a significant role in the pathogenesis of various lung diseases, particularly ILDs.
• The multifaceted functions of SPP1 in inflammation and tissue remodeling make it a critical factor in fibrotic lung diseases.
• SPP1 represents a promising therapeutic target for managing and treating lung diseases, especially those involving fibrosis.