Browsing by Subject "Osteopontin"

Now showing 1 - 4 of 4
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    Dataset of the project: Una Posible Diana Terapeutica para Bloquear la Progresión del Glioblastoma: la Autofagia Mediada por Chaperonas en Pericitos (PID2020-114010RB-I00)
    (2026-02-09) Rodríguez, Pablo; Rubio Pedraza, Gonzalo; Valdor Alonso, Rut; Salinas Hidalgo, María Dolores; Bioquímica y Biología Molecular B e Inmunología
    Glioblastoma (GB) is one of the most aggressive and treatment-resistant cancers due to its complex tumor microenvironment (TME). We previously showed that GB progression is dependent on the aberrant induction of chaperone-mediated autophagy (CMA) in pericytes (PCs), which promotes TME immunosuppression through the PC secretome
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    Expression of lumican and osteopontin in perivascular areas of the glioblastoma peritumoral niche and its value for prognosis
    (MDPI, 2024-12-29) Rodríguez, Pablo; Rubio Pedraza, Gonzalo; Salinas Hidalgo, María Dolores; Valdor Alonso, Rut; Bioquímica y Biología Molecular B e Inmunología
    Glioblastoma (GB) is one of the most aggressive and treatment-resistant cancers due to its complex tumor microenvironment (TME). We previously showed that GB progression is dependent on the aberrant induction of chaperone-mediated autophagy (CMA) in pericytes (PCs), which promotes TME immunosuppression through the PC secretome. The secretion of extracellular matrix (ECM) proteins with anti-tumor (Lumican) and pro-tumoral (Osteopontin, OPN) properties was shown to be dependent on the regulation of GB-induced CMA in PCs. As biomarkers are rarely studied in TME, in this work, we aimed to validate Lumican and OPN as prognostic markers in the perivascular areas of the peritumoral niche of a cohort of GB patients. Previously, we had validated their expression in GB xenografted mice presenting GB infiltration (OPN) or GB elimination (Lumican) dependent on competent or deficient CMA PCs, respectively. Then, patient sample classification by GB infiltration into the peritumoral brain parenchyma was related to GB-induced CMA in microvasculature PCs, analyzing the expression of the lysosomal receptor, LAMP-2A. Our results revealed a correlation between GB-induced CMA activity in peritumoral PCs and GB patients’ outcomes, identifying three degrees of severity. The perivascular expression of both immune activation markers, Iba1 and CD68, was related to CMA-dependent PC immune function and determined as useful for efficient GB prognosis. Lumican expression was identified in perivascular areas of patients with less severe outcome and partially co-localizing with PCs presenting low CMA activity, while OPN was primarily found in perivascular areas of patients with poor outcome and partially co-localizing with PCs presenting high CMA activity. Importantly, we found sex differences in the incidence of middle-aged patients, being significantly higher in men but with worse prognosis in women. Our results confirmed that Lumican and OPN in perivascular areas of the GB peritumoral niche are effective predictive biomarkers for evaluating prognosis and monitoring possible therapeutic immune responses dependent on PCs in tumor progression.
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    Osteopontin expression and localization of Ca2+ deposits in early stages of osteoarthritis in a rat model
    (F. Hernández y Juan F. Madrid. Universidad de Murcia. Departamento de Biología Celular e Histología, 2014) Martínez Calleja, América; Velasquillo, Cristina; Vega López, Marco A.; Arellano Jiménez, M. Josefina; Tsutsumi Fujiyoshi, Victor K.; Mondragón Flores, Ricardo; Kouri Flores, Juan B.
    Calcium deposits have been related to articular cartilage (AC) degeneration and have been observed in late stages of osteoarthritis (OA). However, the role of those deposits, whether they induce the OA pathogenesis or they appear as a consequence of such process, is still unknown. In this work, we present the kinetics of expression and tissue localisation of osteopontin (OPN), a mineralisation biomarker, and calcium deposits in samples from (normal, sham) and osteoarthritic cartilage (in a rat model). Immunohisto-chemical and Western blot assays for OPN, as well as Alizarin red staining for calcium deposits were performed; superficial, middle, and deep zones of AC were analysed. An increased expression of OPN and calcium deposits was found in the osteoarthritic cartilage compared with that of control groups, particularly in the superficial zone of AC in early stages of OA. In addition, the expression and localisation of OPN and calcium deposits during the OA pathogenesis suggest that the pathological AC mineralisation starts in the superficial zone during OA pathogenesis.
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    Osteopontin is histochemically detected by the AgNOR acid-silver staining
    (Murcia : F. Hernández, 2008) Gaudin-Audrain, Christine; Gallois, Yves; Pascaretti-Grizon, Florence; Hubert, Laurent; Massin, Philippe; Baslé, Michael-Félix; Chappard, Daniel
    Silver nitrate staining of decalcified bone sections is known to reveal osteocyte canaliculi and cement lines. Nucleolar Organising Regions (NOR) are part of the nucleolus, containing argyrophilic proteins (nucleoclin/C23, nucleophosmin/B23) that can be identified by silver staining at low pH. The aim of this study was to clarify the mechanism explaining why AgNOR staining also reveals osteocyte canaliculi. Human bone and kidney sections were processed for silver staining at light and electron microscopy with a modified method used to identify AgNOR. Sections were processed in parallel for immunohistochemistry with an antibody direct against osteopontin. Protein extraction was done in the renal cortex and decalcified bone and the proteins were separated by western blotting. Purified hOPN was also used as a control. Proteins were electro-transferred on polyvinylidene difluoride membranes and stained for AgNOR proteins. In bone, Ag staining identified AgNOR in cell nuclei, as well as in osteocyte canaliculi, cement and resting lines. In the distal convoluted tubules of the kidney, silver deposits were also observed in cytoplasmic granules on the apical side of the cells. Immunolocalization of osteopontin closely matched with all these locations in bone and kidney. Ag staining of membranes at low pH revealed bands for NOR proteins and 56 KDa (kidney), 60KDa (purified hOPN) and 75 KDa (bone) bands that corresponded to osteopontin. NOR proteins and osteopontin are proteins containing aspartic acid rich regions that can bind Ag. Staining protocols using silver nitrate at low pH can identify these proteins on histological sections or membranes.