LncRNA MALAT1/microRNA-30b axis regulate macrophage polarization and function.

Area of Science:

• Immunology
• Molecular Biology
• Noncoding RNA Research

Background:

• Macrophages (Mφ) exhibit polarization into M1 (proinflammatory) or M2 (proresolving) phenotypes, crucial for inflammation and tissue repair.
• The precise roles of noncoding RNAs in regulating Mφ polarization and immune responses are not fully understood.

Approach:

• Investigated the relationship between long noncoding RNA MALAT1 and microRNA miR-30b in Mφ polarization.
• Analyzed MALAT1 and miR-30b expression in differentiating Mφ, human, and murine inflamed gingival tissues.
• Utilized dual-luciferase assays to confirm direct interaction and assessed the functional impact of MALAT1 knockdown and miR-30b overexpression on Mφ functions.

Key Points:

• MALAT1 expression is induced during Mφ differentiation and favors the M1 phenotype by suppressing M2 polarization.
• MALAT1 knockdown impairs Mφ phagocytosis, antigen processing, and cytokine secretion, highlighting its role in innate immunity.
• MALAT1 directly interacts with miR-30b, and they exhibit an antagonistic relationship, with miR-30b promoting the M2 phenotype.

Conclusions:

• The MALAT1/miR-30b interaction antagonistically shapes Mφ polarization both in vitro and in inflamed gingival tissues.
• Elevated MALAT1 and reduced miR-30b levels in periodontal disease correlate with increased M1 Mφ markers, suggesting a pro-inflammatory role.