Abstract
The aim of this study was to evaluate macrophages repolarization from pro-inflammatory M1 to anti-inflammatory M2 phenotype upon transfection with microRNA-223 (miR-223) duplexes and miR-223 expressing plasmid DNA encapsulated in CD44-targeting hyaluronic acid-poly(ethyleneimine) (HA-PEI) nanoparticles (NPs). The HA-PEI/miR-223 NPs with spherical shape and an average diameter of 200 nm were efficiently internalized by J774A.1 alveolar and primary peritoneal macrophages and non-cytotoxic at HA-PEI concentration less than 200 μg/mL. Transfection of HA-PEI/miR-223 NPs in J774A.1 macrophages showed significantly higher miR-223 expression than that with HA-PEI/plasmid DNA expressing miR-223 (pDNA-miR-223). HA-PEI/miR-223 NPs mediated transfection increased miR-223 expression to 90 fold in primary peritoneal macrophages compared to untreated cells. The overexpression of miR-223 in both J774A.1 and peritoneal macrophages induced a phenotypic change from M1 to M2 state as indicated by a decrease in iNOS-2 (M1 marker) and an increase in Arg-1 (M2 marker) levels compared to those in lipopolysaccharide (LPS) and interferon-gamma (IFN-γ)-stimulated macrophages (M1). The change in macrophage phenotype by HA-PEI/miR-223 NPs could suppress the inflammation in peritoneal macrophages induced by LPS as evidenced by a significant decrease in pro-inflammatory cytokine levels TNF-α, IL-1β and IL-6, compared to LPS-stimulated peritoneal macrophages without treatment. The results demonstrated that miR-223-encapsulated HA-PEI NPs modulated macrophage polarity toward an anti-inflammatory M2 phenotype, which has potential for the treatment of inflammatory diseases.
Highlights
Tissue-associated macrophages, derived from myeloid precursor cells in the bone marrow, are important cellular components of the host innate and adaptive immune system
We evaluated cytotoxicity of hyaluronic acid-poly(ethyleneimine) (HA-PEI) in J774A.1 macrophages by MTT assay after 24 h incubation with different concentrations of HA-PEI ranging from 1 μg/mL to 1000 μg/mL
The results indicated that J774A.1 macrophages were effectively re-polarized from M1 to M2 state by miR-223 duplex and pDNA-miR-223 encapsulated in HA-PEI NPs
Summary
Tissue-associated macrophages, derived from myeloid precursor cells in the bone marrow, are important cellular components of the host innate and adaptive immune system. MiR-223 Induced Macrophage Repolarization are highly plastic cells, which are maintained under physiological homeostasis in a spectrum of functional polarization states based on the microenvironmental signaling [1,2]. In the presence of an inflammatory stimulus, such as with interferon gamma (IFN-γ) and lipopolysaccharide (LPS), macrophages polarize to M1 phenotype with increased production of pro-inflammatory cytokines such as tumor necrosis factor alpha (TNF-α), interleukin-1beta (IL-1β) and interleukin-6 (IL-6) [3]. In the wound-healing environment or in the presence of anti-inflammatory cytokines, such as IL-4 or IL-10, macrophages shift to a predominant M2 phenotype with high secretion of anti-inflammatory cytokines IL-4, IL-10, transforming growth factor beta (TGF-β) for tissue repair and re-modeling [4,5]. It has been reported that macrophages exist predominantly in M1 phenotype causing tissue damage in chronic inflammatory and autoimmune diseases [6]. There has been no therapy for macrophage-targeting and modulating their phenotype currently on the market, which open a new area for investigation [2]
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