A novel fluorescent probe for peroxynitrite, PN(600), was rationally designed on the basis of a unique fluorophore assembly approach. PN(600) is a green-emitting coumarin derivative. Upon oxidation by peroxynitrite, PN(600) is transformed into a highly fluorescent red-emitting resorufin derivative via an orange-emitting intermediate. This three-channel signaling capability enables PN(600) to differentiate peroxynitrite from other reactive oxygen and nitrogen species, including hypochlorite and hydroxyl radical. Moreover, PN(600) is membrane-permeable and compatible with common TRITC filter sets and displays low cytotoxicity. Therefore, PN(600) is a promising candidate for in vitro peroxynitrite imaging.

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The immune contexture, a composition of the tumor microenvironment, plays multiple important roles in cancer stem cell (CSC) and epithelial-mesenchymal transition (EMT), and hence critically influences tumor initiation, progression and patient outcome. Tumor-associated macrophages (TAMs) are abundant in immune contexture, however their roles in CSC, EMT and prognosis of colorectal cancer (CRC) have not been elucidated. In 419 colorectal carcinomas, immune cell types (CD68 macrophages, CD3, CD4 or CD8 T lymphocytes, CD20 B lymphocytes), EMT markers (E-cadherin and Snail) as well as the stem cell marker (CD44v6) were detected in tumor center (TC) and tumor invasive front (TF) respectively by immunohistochemistry. Tumor buds, that represent EMT phenotype, were also counted. It was found CD68 macrophages were the most infiltrating immune cells in CRC. By correlation analysis, more CD68 macrophages were associated with more CD44v6 expression (p < 0.001), lower Snail expression (p = 0.08) and fewer tumor buds (p < 0.001). More CD68 macrophages were significantly related to more CD3 T lymphocytes (p = 0.002), CD8 T lymphocytes (p < 0.001) and CD20 B lymphocytes counts (p = 0.004). Strong CD68 macrophages infiltration also predicted long term overall survival. CRC patients with more tumor buds had worse survival. However, strong CD68 macrophages infiltration could reverse the unfavorable results since patients with more tumor buds but increasing CD68 macrophages infiltration had the favorable outcome, similar to lower tumor buds groups. This study provided direct morphological evidence that tumor-associated macrophages in the invasive front play critical roles in fighting with the unfavorable results of tumor buds, thus resulting favorable outcomes for CRC patients.

Mesenchymal stem cell-based therapy has great therapeutic potential for temporomandibular joint (TMJ) cartilage repair. However, the behavior of mesenchymal stem cells in the inflammatory milieu following their delivery remains poorly understood. Synovial fluid-derived mesenchymal stem cells (SFMSCs) are a promising resource for TMJ cartilage repair, as they are easily obtained from patients with TMJ disorders (TMD). In this study, we obtained SFMSCs from patients with TMD and expanded them in vitro; we then stimulated the cells with interleukin (IL)-8, IL-1β, IL-6, IL-10, tumor necrosis factor (TNF)-α and IL-12p. The cells expressed CD90, CD44, CD105 and CD73, and were negative for CD45, CD34, CD11b, CD19 and HLA-DR. They could be induced to differentiate into osteogenic, chondrogenic, adipogenic and neurogenic lineages in vitro. Only the levels of IL-6 and IL-8 were upregulated significantly following stimulation with IL-8, IL-1β, IL-6, IL-10, TNF-α and IL-12p. Furthermore, IL-6 and IL-8 expression was driven mainly by IL-1β-dependent nuclear factor-κB (NF-κB) pathway activation, and was independent of IL-8, IL-6, IL-10, TNF-α and IL-12p. IL-6 and IL-8 expression was inhibited completely by treatment with the NF-κB inhibitor, BAY11-7082. SRY-box 9 (SOX9) was downregulated and matrix metalloproteinase (MMP)13 was upregulated upon chondrogenic differentiation induced in the cells also exposed to IL-1β. Sulfated glycosaminoglycan production was also reduced upon chondrogenic differentiation in the presence of IL-6, but not IL-8. Thus, IL-1β in the inflammatory milieu is crucial in regulating SFMSCs. In doing so, IL-1β impedes the chondrogenic differentiation of SFMSCs. The upregulation of IL-6 and NF-κB pathway activation also contribute to this biological behavior. The findings of our study indicate the potential adverse effects of IL-1β on the chondrogenic differentiation of SFMSCs, and may thus provide new insight into the pathogenesis of TMD.