Reprogramming Inflammatory Macrophages with Specialized Pro-Resolving Lipid Mediators: A Novel Immunotherapeutic Strategy for Asthma

Asthma is defined as a chronic airway inflammatory disorder with over-activation of the immune system accompanied by the inability to resolve inflammation. SPMs are novel potent lipid mediators that play an important role in maintaining inflammation homeostasis and macrophages’ functional plasticity. This review will look into the potential function of SPM-programmed macrophage reprogramming as a novel therapeutic strategy for asthma. Unlike current anti-inflammatory treatments, which only focus on suppressing inflammation, SPMs can actively drive the inflammation resolution phase by promoting efferocytosis and wound healing while maintaining the defense against infection. In experimental asthma animal models, lipoxins, resolvins, protectins, and maresins have been demonstrated to alleviate inflammation and airway hyperresponsiveness, shift macrophages towards pro-resolving phenotypes and thus facilitate the resolution process. Levels of some SPM subclasses were found to be reduced in severe or uncontrolled asthmatics, indicating defective resolution pathways may contribute to asthma persistence. The mechanisms include down-regulation of pro-inflammatory cytokines, alteration of macrophage phenotype, improvement of immune homeostasis in the airway milieu, etc. These molecules have become highly promising therapeutic agents after the development of metabolically stable analogs, receptor-targeted agonists, and an improved delivery system. Multi-omics studies coupled with patient stratification based on biomarkers will potentially help in the future to develop personalized resolution-based therapy, in particular for those steroid-resistant and non-type 2 asthmatics. Nevertheless, the evidence provided so far is mainly preclinical; more challenges in terms of pharmacokinetics, formulation and formulation development, regulatory agency approval, and clinical validation remain and will be overcome through further studies, thus warranting investigation into SPM-mediated strategies for asthma and other chronic inflammatory diseases.