RESUMEN
The neural cell adhesion molecule (NCAM), a key member of the immunoglobulin-like CAM family, was reported to regulate the migration of bone marrow-derived mesenchymal stem cells (BMSCs). However, the detailed cellular behaviors including lamellipodia formation in the initial step of directional migration remain largely unknown. In the present study, we reported that NCAM affects the lamellipodia formation of BMSCs. Using BMSCs from Ncam knockout mice we found that Ncam deficiency significantly impaired the migration and the directional lamellipodia formation of BMSCs. Further studies revealed that Ncam knockout decreased the activity of cofilin, an actin-cleaving protein, which was involved in directional protrusions. To explore the molecular mechanisms involved, we examined protein tyrosine phosphorylation levels in Ncam knockout BMSCs by phosphotyrosine peptide array analyses, and found that the tyrosine phosphorylation level of ß1 integrin, a protein upstream of cofilin, was greatly upregulated in Ncam-deficient BMSCs. Notably, by blocking the function of ß1 integrin with RGD peptide or ROCK inhibitor, the cofilin activity and directional lamellipodia formation of Ncam knockout BMSCs could be rescued. Finally, we found that the effect of NCAM on tyrosine phosphorylation of ß1 integrin was independent of the fibroblast growth factor receptor. These results indicated that NCAM regulates directional lamellipodia formation of BMSCs through ß1 integrin signal-mediated cofilin activity.
Asunto(s)
Factores Despolimerizantes de la Actina/metabolismo , Células de la Médula Ósea/metabolismo , Movimiento Celular , Integrina beta1/metabolismo , Células Madre Mesenquimatosas/metabolismo , Moléculas de Adhesión de Célula Nerviosa/metabolismo , Factores Despolimerizantes de la Actina/genética , Animales , Células de la Médula Ósea/citología , Células Cultivadas , Integrina beta1/genética , Células Madre Mesenquimatosas/citología , Ratones , Ratones Noqueados , Moléculas de Adhesión de Célula Nerviosa/genética , Seudópodos/genética , Seudópodos/metabolismoRESUMEN
Chitosan/strontium-substituted hydroxyapatite (CHI/SrHAP) coatings were prepared on titanium substrate by electrochemical deposition technique containing Sr2+, Ca2+, PO4(3-) and Chitosan. The as-prepared coatings were examined by scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) tests. The results indicate that the CHI/SrHAP coatings take the morphology of flake-like rather than the needle-like crystal , and the composite coating becomes more compact. The FTIR test indicates that the typical vibration absorption peaks of chitosan (amide I and amide II) emerged, simulated body fluid immersion test proved that the CHI/SrHAP coatings had induced carbonate-apatite formation, indicating that the composite coating possesses excellent biocompatibility. In the electrochemical corrosion testing, that the CHI/SrHAP coatings showed stronger corrosion resistance than pure Ti.
Asunto(s)
Quitosano/química , Materiales Biocompatibles Revestidos , Hidroxiapatitas/química , Espectroscopía Infrarroja por Transformada de Fourier , Estroncio/química , Titanio/química , Apatitas , Líquidos Corporales , Corrosión , Técnicas Electroquímicas , Difracción de Rayos XRESUMEN
PRDM (PRDI-BF1 and RIZ domain-containing) proteins constitute a family of zinc finger proteins and play important roles in multiple cellular processes by acting as epigenetic modifiers. PRDM5 is a recently identified member of the PRDM family and may function as a tumor suppressor in several types of cancer. However, the role of PRDM5 in murine melanoma remains largely unknown. In our study, effect of PRDM5 on murine melanoma cells was determined and results showed that PRDM5 overexpression significantly promoted proliferation, migration, and invasion of murine melanoma B16F10 cells. Consistently, silencing of PRDM5 expression significantly inhibited proliferation, invasion, and migration of B16F10 cells. In vivo study also showed that PRDM5 silencing significantly inhibited the growth and metastasis of melanoma in mice. PRDM5 was then found to increase the expression and activation of JNK in B16F10 cells. JNK silencing significantly reduced PRDM5-mediated up-regulation of JNK expression and blocked the PRDM5-induced proliferation and invasion of B16F10 cells. To further verify the involvement of JNK signaling in PRDM5-induced progression of B16F10 cells, a specific JNK inhibitor was employed to inhibit the JNK signaling pathway, and results showed that PRDM5-induced proliferation and invasion of B16F10 cells were abolished. We conclude that PRDM5 promotes the proliferation and invasion of murine melanoma cells through up-regulating JNK expression and strategies targeting PRDM5 may be promising for the therapy of melanoma.