PubMed · 9593478
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K Muroi, K Omine, R Kuribara, M Uchida, T Izumi, K Hatake, Y Miura. 1998. CD56 expression in B-cell lymphoma.. https://doi.org/10.1016/s0145-2126(97)00153-7
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To help understand the role of chemokines in NK cell trafficking, we determined the chemokine receptor profiles of three different human NK cell lines and freshly isolated primary human NK cells. The cell lines overlapped in their chemokine receptor profiles: CXCR3 and CXCR4 were expressed by all three lines, whereas CCR1, CCR4, CCR6, CCR7, and CX3CR1 were expressed by only one or two of the lines, and no other chemokine receptors were detected. Freshly isolated primary NK cells were found to express CXCR1, CXCR3, and CXCR4, and to contain subsets expressing CCR1, CCR4, CCR5, CCR6, CCR7, CCR9, CXCR5, and CXCR6. With the exception of CCR4, these chemokine receptors were expressed at higher percentages by CD56(bright) NK cells than by CD56(dim) NK cells. In particular, CCR7 was expressed by almost all CD56(bright) NK cells but was not detected on CD56(dim) NK cells. CCR9 and CXCR6 have not been described previously on primary NK cells. These results indicate that within both the CD56(bright) and CD56(dim) NK cell populations, subsets with the capacity for differential trafficking programs exist, which likely influence their functions in innate and adaptive immunity.
Toll-like receptor (TLR) ligands are potent inducers of the innate immune system, of which NK and NKT cells play an important role. We examined the direct activation of highly purified human NK and/or NKT cells with known TLR ligands. NK/NKT cells were positive for all known TLR mRNA (TLR1-10). Ligands for TLR2-5 induced production of significant amounts of IFN-gamma by purified NK cells. However, a TLR9 ligand failed to induce significant levels of the cytokine. NK cells were depleted from PBMCs to confirm that they were the main source of IFN-gamma following treatment with TLR ligands, which resulted in a significant decrease in cytokines. The direct effects of TLR ligands on NK cytotoxicity were determined using 51Cr-labeled K562 target cells. Ligands for TLR2-5 were potent inducers of NK cell cytotoxicity, a TLR9 ligand was not. Our results suggest that TLR ligands can directly stimulate and enhance NK cell cytokine production and induce cytotoxic activities.
Mutations in dysferlin cause a type of muscular dystrophy known as dysferlinopathy. Dysferlin may be involved in muscle repair and differentiation. We compared normal human skeletal muscle cultures expressing dysferlin with muscle cultures from dysferlinopathy patients. We quantified the fusion index of myoblasts as a measure of muscle development and conducted optic and electronic microscopy, immunofluorescence, Western blot, flow cytometry, and real-time PCR at different developmental stages. Short interference RNA was used to corroborate the results obtained in dysferlin-deficient cultures. A luciferase reporter assay was performed to study myogenin activity in dysferlin-deficient cultures. Myoblasts fusion was consistently delayed as compared with controls whereas the proliferation rate did not change. Electron microscopy showed that control cultured cells at 10 days were fusiform, whereas dysferlin-deficient cells were star-shaped and large. After 15 days the normal multinucleated appearance and structured myofibrils were not present in dysferlin-deficient cells. Strikingly, myogenin was not detected in myotubes from dysferlin-deficient cultures using Western blot, and mRNA analysis showed low levels (p < 0.05) compared with controls. Flow cytometry and immunofluorescence also showed reduced levels of myogenin in dysferlin-deficient cultures. When the dysferlin gene was knocked down ( approximately 80%), myogenin mRNA leveled down to approximately 70%. MyoD and desmin mRNA levels in controls and dysferlin-deficient cultures were similar. The reporter luciferase assay demonstrated a low myogenin activity in dysferlin-deficient cultures. These results point to a functional link between dysferlin and myogenin, and both proteins may share a new signaling pathway involved in differentiation of skeletal muscle in vitro.