Purpurolide C-based microneedle promotes macrophage-mediated diabetic wound healing via inhibiting TLR4-MD2 dimerization and MYD88 phosphorylation

Delayed wound healing in diabetes is a global challenge, and the development of related drugs is a clinical problem to be solved. In this study, purpurolide C (PC), a small-molecule secondary metabolite of the endophytic fungus Penicillium purpurogenum, was found to promote diabetic wound healing. To investigate the key regulation targets of PC, in vitro RNA-seq, molecular docking calculations, TLR4-MD2 dimerization SDS-PAGE detection, and surface plasmon resonance (SPR) were performed, indicating that PC inhibited inflammatory macrophage activation by inhibiting both TLR4-MD2 dimerization and MYD88 phosphorylation. Tlr4 knockout in vivo attenuated the promotion effect of PC on wound healing. Furthermore, a delivery system consisting of macrophage liposome and GelMA-based microneedle patches combined with PC (PC@MLIP MN) was developed, which overcame the poor water solubility and weak skin permeability of PC, so that successfully punctured the skin and delivered PC to local tissues, and accurately regulated macrophage polarization in diabetic wound management. Overall, PC is an anti-inflammatory small molecule compound with a well-defined structure and dual-target regulation, and the PC@MLIP MN is a promising novel biomaterial for the management of diabetic wound.

Mesenchymal stem cell-derived apoptotic bodies alleviate alveolar bone destruction by regulating osteoclast differentiation and function / 国际口腔科学杂志·英文版

Periodontitis is caused by overactive osteoclast activity that results in the loss of periodontal supporting tissue and mesenchymal stem cells (MSCs) are essential for periodontal regeneration. However, the hypoxic periodontal microenvironment during periodontitis induces the apoptosis of MSCs. Apoptotic bodies (ABs) are the major product of apoptotic cells and have been attracting increased attention as potential mediators for periodontitis treatment, thus we investigated the effects of ABs derived from MSCs on periodontitis. MSCs were derived from bone marrows of mice and were cultured under hypoxic conditions for 72 h, after which ABs were isolated from the culture supernatant using a multi-filtration system. The results demonstrate that ABs derived from MSCs inhibited osteoclast differentiation and alveolar bone resorption. miRNA array analysis showed that miR-223-3p is highly enriched in those ABs and is critical for their therapeutic effects. Targetscan and luciferase activity results confirmed that Itgb1 is targeted by miR-223-3p, which interferes with the function of osteoclasts. Additionally, DC-STAMP is a key regulator that mediates membrane infusion. ABs and pre-osteoclasts expressed high levels of DC-STAMP on their membranes, which mediates the engulfment of ABs by pre-osteoclasts. ABs with knock-down of DC-STAMP failed to be engulfed by pre-osteoclasts. Collectively, MSC-derived ABs are targeted to be engulfed by pre-osteoclasts via DC-STAMP, which rescued alveolar bone loss by transferring miR-223-3p to osteoclasts, which in turn led to the attenuation of their differentiation and bone resorption. These results suggest that MSC-derived ABs are promising therapeutic agents for the treatment of periodontitis.

Liver macrophages show an immunotolerance phenotype in nonalcoholic fatty liver combined with Porphyromonas gingivalis-lipopolysaccharide infection / 华西口腔医学杂志

OBJECTIVES@#This study aimed to explore the functions and potential regulatory targets of local macrophages in nonalcoholic fatty liver combined with Porphyromonas gingivalis (P. gingivalis)infection.@*METHODS@#Single-cell RNA sequencing was used to analyze the phenotypes and functional changes in various cells in the liver tissue of nonalcoholic steatohepatitis (NASH) mice fed with P. gingivalis. Real-time polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay, and immunofluorescence staining were applied to observe the inflammation and expression levels of macrophage antigen presenting functional markers in the NASH liver. Oil red staining was performed to observe the accumulation of local adipose tissue in the NASH liver. Results were verified through RT-PCRand RNA sequencing using P. gingivalis-lipopolysaccharide treated mouse peritoneal macrophages.@*RESULTS@#In comparison with healthy livers with Kupffer cells, the NASH liver combined with P. gingivalis infection-related macrophages showed significant heterogeneity. C1qb, C1qc, Mafb, Apoe, and Cd14 were highly expressed, but Cd209a, H2-Aa, H2-Ab1, and H2-DMb1, which are related to the antigen presentation function, were weakly expressed. Further in vivo and in vitro investigations indicated that the activation and infiltration of these macrophages may be due to local P. gingivalis-lipopolysaccharide accumulation.@*CONCLUSIONS@#P. gingivalis-lipopolysaccharide induces a local macrophage immunotolerance phenotype in nonalcoholic fatty liver, which may be the key mechanism of periodontitis pathogen infection that promotes NASH inflammation and pathogenesis. This study further clarifies the dysfunction and regulatory mechanisms of macrophages in the pathogenesis of P. gingivalis-infected NASH, thereby providing potential therapeutic targets for its clinical treatment.