RESUMEN
BACKGROUND: We have previously reported the aberrant expression of Fibromodulin (FMOD) in patients with chronic lymphocytic leukemia (CLL). Although FMOD has been considered as a cytoplasmic or secretory protein, we discovered the cell surface expression of FMOD in leukemic B cells via anchoring with glycosylphosphatidylinositol (GPI). OBJECTIVE: To evaluate FMOD as a new biomarker in CLL patients in comparison with healthy individuals. METHODS: A monoclonal antibody was generated against human FMOD. The cell surface expression of FMOD in 52 CLL patients and 45 healthy individuals were compared by flow cytometry. A bacterial phosphatidylinositol-specific phospholipase C (PI-PLC) was used to determine the cell surface localization of FMOD using ELISA and flow cytometry techniques. Annexin V-FITC and propidium iodide (PI) was used to detect apoptosis induction in CLL PBMCs following in vitro incubation with anti-FMOD mAb. RESULTS: The results demonstrated the widespread cell surface expression of GPI-anchored FMOD in CLL patients (median: 79.9 %), although healthy individuals had low FMOD expression (median: 6.2 %) (p≤0.0001). The cut-off value of FMOD expression was estimated with high sensitivity and specificity at 17.9 %. Furthermore, in vitro apoptosis induction of leukemic cells following incubation with anti-FMOD mAb showed a direct apoptosis of CLL cells (27.9%) with very low effect on healthy PBMCs (6%). CONCLUSION: The membrane-anchoring of FMOD by means of a GPI moiety in leukemic cells supports FMOD as a highly potential diagnostic and therapeutic target in CLL patients.
Asunto(s)
Linfocitos B/patología , Fibromodulina/metabolismo , Leucemia Linfocítica Crónica de Células B/diagnóstico , Proteínas de la Membrana/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Anticuerpos Monoclonales/uso terapéutico , Apoptosis , Linfocitos B/metabolismo , Línea Celular Tumoral , Femenino , Fibromodulina/química , Fibromodulina/inmunología , Regulación Neoplásica de la Expresión Génica , Glicosilfosfatidilinositoles/química , Humanos , Leucemia Linfocítica Crónica de Células B/tratamiento farmacológico , Masculino , Proteínas de la Membrana/química , Proteínas de la Membrana/inmunología , Persona de Mediana Edad , Unión Proteica , Sensibilidad y EspecificidadRESUMEN
BACKGROUND: Collagen type I, proteoglycans (PG) and non-collagenous proteins represent important building blocks of the dentine matrix. While different PGs have been identified in dentine, changes in the distribution of these macromolecules with the progression of caries have been poorly characterized. The aim of this study was to compare the immunolocalization of three small collagen-binding PGs (biglycan, fibromodulin and lumican) as well as collagen (types I and VI) in healthy versus carious dentine. METHODS: Longitudinal demineralized sections of extracted teeth were stained with antibodies recognizing specific PG core proteins and collagens, as well as glycosaminoglycans (GAGs) with toluidine blue. RESULTS: In healthy dentine, PGs appeared to be more abundant near the tubule walls and directly under the cusps. Conversely, in carious dentine, specific locations appeared to be more prone to PG degradation than others. These degradation patterns were well correlated with the progression of caries into the tissue, and also appeared to trigger interesting morphological changes in the tissue structure, such as the deformation of dentine tubules near highly infected areas and the lower concentration of PG in tertiary dentine. CONCLUSIONS: This study presents new insights into the involvement of PGs in the progression of caries.