Fabrication of Interleukin-4 Encapsulated Bioactive Microdroplets for Regulating Inflammation and Promoting Osteogenesis.
Int J Nanomedicine 2023;
18:2019-2035. [PMID:
37155503 PMCID:
PMC10122853 DOI:
10.2147/ijn.s397359]
[Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Accepted: 04/11/2023] [Indexed: 05/10/2023] Open
Abstract
Background
Despite the inherent regenerative ability of bone, large bone defect regeneration remains a major clinical challenge for orthopedic surgery. Therapeutic strategies medicated by M2 phenotypic macrophages or M2 macrophage inducer have been widely used to promote tissue remodeling. In this study, ultrasound-responsive bioactive microdroplets (MDs) encapsulated with bioactive molecule interleukin-4 (IL4, hereafter designated MDs-IL4) were fabricated to regulate macrophage polarization and potentiate the osteogenic differentiation of human mesenchymal stem cells (hBMSCs).
Materials and Methods
The MTT assay, live and dead staining, and phalloidin/DAPI dual staining were used to evaluate biocompatibility in vitro. H&E staining was used to evaluate biocompatibility in vivo. Inflammatory macrophages were further induced via lipopolysaccharide (LPS) stimulation to mimic the pro-inflammatory condition. The immunoregulatory role of the MDs-IL4 was tested via macrophage phenotypic marker gene expression, pro-inflammatory cytokine level, cell morphological analysis, and immunofluorescence staining, etc. The immune-osteogenic response of hBMSCs via macrophages and hBMSCs interactions was further investigated in vitro.
Results
The bioactive MDs-IL4 scaffold showed good cytocompatibility in RAW 264.7 macrophages and hBMSCs. The results confirmed that the bioactive MDs-IL4 scaffold could reduce inflammatory phenotypic macrophages, as evidenced by changing in morphological features, reduction in pro-inflammatory marker gene expression, increase of M2 phenotypic marker genes, and inhibition of pro-inflammatory cytokine secretion. Additionally, our results indicate that the bioactive MDs-IL4 could significantly enhance the osteogenic differentiation of hBMSCs via its potential immunomodulatory properties.
Conclusion
Our results demonstrate that the bioactive MDs-IL4 scaffold could be used as novel carrier system for other pro-osteogenic molecules, thus having potential applications in bone tissue regeneration.
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