Browsing by Author "Carvajal, Francisco J."

Now showing 1 - 4 of 4
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    Epstein-Barr Virus BARF1 Is Expressed in Lung Cancer and Is Associated with Cancer Progression
    (2024) Osorio, Julio C.; Armijo, Alvaro; Carvajal, Francisco J.; Corvalan, Alejandro H.; Castillo, Andres; Fuentes-Panana, Ezequiel M.; Moreno-Leon, Carolina; Romero, Carmen; Aguayo, Francisco
    Background: Epstein-Barr virus (EBV) is involved in the development of lymphomas, nasopharyngeal carcinomas (NPC), and a subgroup of gastric carcinomas (GC), and has also been detected in lung carcinomas, even though the role of the virus in this malignancy has not yet been established. BamH1-A Rightward Frame 1 (BARF1), a suggested exclusive epithelial EBV oncoprotein, is detected in both EBV-associated GCs (EBVaGC) and NPC. The expression and role of BARF1 in lung cancer is unknown. Methods: A total of 158 lung carcinomas including 80 adenocarcinomas (AdCs) and 78 squamous cell carcinomas (SQCs) from Chilean patients were analyzed for EBV presence via polymerase chain reaction (PCR), Immunohistochemistry (IHC), or chromogenic in situ hybridization (CISH). The expression of BARF1 was evaluated using Reverse Transcription Real-Time PCR (RT-qPCR). Additionally, A549 and BEAS-2B lung epithelial cells were transfected with a construct for ectopic BARF1 expression. Cell proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) were evaluated. Results: We found that EBV was present in 37 out of 158 (23%) lung carcinomas using PCR. Considering EBV-positive specimens using PCR, IHC for Epstein-Barr nuclear antigen 1 (EBNA1) detected EBV in 24 out of 30 (80%) cases, while EBERs were detected using CISH in 13 out of 16 (81%) cases. Overall, 13 out of 158 (8%) lung carcinomas were shown to be EBV-positive using PCR/IHC/CISH. BARF1 transcripts were detected in 6 out of 13 (46%) EBV-positive lung carcinomas using RT qPCR. Finally, lung cells ectopically expressing BARF1 showed increased migration, invasion, and EMT. Conclusions. EBV is frequently found in lung carcinomas from Chile with the expression of BARF1 in a significant subset of cases, suggesting that this viral protein may be involved in EBV-associated lung cancer progression.
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    Glutamatergic Receptor Trafficking and Delivery: Role of the Exocyst Complex
    (NLM (Medline), 2020) Lira, Matías; Mira, Rodrigo G.; Cerpa Nebott Waldo Francisco; Carvajal, Francisco J.; Inestrosa, Nibaldo C.; Zamorano, Pedro
    Cells comprise several intracellular membrane compartments that allow them to function properly. One of these functions is cargo movement, typically proteins and membranes within cells. These cargoes ride microtubules through vesicles from Golgi and recycling endosomes to the plasma membrane in order to be delivered and exocytosed. In neurons, synaptic functions employ this cargo trafficking to maintain inter-neuronal communication optimally. One of the complexes that oversee vesicle trafficking and tethering is the exocyst. The exocyst is a protein complex containing eight subunits first identified in yeast and then characterized in multicellular organisms. This complex is related to several cellular processes, including cellular growth, division, migration, and morphogenesis, among others. It has been associated with glutamatergic receptor trafficking and tethering into the synapse, providing the molecular machinery to deliver receptor-containing vesicles into the plasma membrane in a constitutive manner. In this review, we discuss the evidence so far published regarding receptor trafficking and the exocyst complex in both basal and stimulated levels, comparing constitutive trafficking and long-term potentiation-related trafficking.
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    Peroxisome Proliferator-Activated Receptor (PPAR) γ and PPARα Agonists Modulate Mitochondrial Fusion-Fission Dynamics: Relevance to Reactive Oxygen Species (ROS)-Related Neurodegenerative Disorders?
    (2013) Zolezzi, Juan M.; Silva-Alvarez, Carmen; Ordenes, Daniela; Godoy, Juan A.; Carvajal, Francisco J.; Santos, Manuel J.; Inestrosa, Nibaldo C.
    Recent studies showed that the activation of the retinoid X receptor, which dimerizes with peroxisome proliferator-activated receptors (PPARs), leads to an enhanced clearance of A beta from the brain of transgenic mice model of Alzheimer's disease (AD), because an increased expression of apolipoprotein E and it main transporters. However, the effects observed must involve additional underlying mechanisms that have not been yet explored. Several studies conducted in our laboratory suggest that part of the effects observed for the PPARs agonist might involves mitochondrial function and, particularly, mitochondrial dynamics. In the present study we assessed the effects of oxidative stress challenge on mitochondrial morphology and mitochondrial dynamics-related proteins in hippocampal neurons. Using immunofluorescence, we evaluated the PPAR gamma co-activator 1 alpha (PGC-1 alpha), dynamin related protein 1 (DRP1), mitochondrial fission protein 1 (FIS1), and mitochondrial length, in order to determine if PPARs agonist pre-treatment is able to protect mitochondrial population from hippocampal neurons through modulation of the mitochondrial fusion-fission events. Our results suggest that both a PPAR gamma agonist (ciglitazone) and a PPAR alpha agonist (WY 14.643) are able to protect neurons by modulating mitochondrial fusion and fission, leading to a better response of neurons to oxidative stress, suggesting that a PPAR based therapy could acts simultaneously in different cellular components. Additionally, our results suggest that PGC-1 alpha and mitochondrial dynamics should be further studied in future therapy research oriented to ameliorate neurodegenerative disorders, such as AD.
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    Tetrahydrohyperforin Induces Mitochondrial Dynamics and Prevents Mitochondrial Ca2+ Overload after Aβ and Aβ-AChE Complex Challenge in Rat Hippocampal Neurons
    (2013) Zolezzi, Juan M.; Carvajal, Francisco J.; Rios, Juvenal A.; Ordenes, Daniela; Silva-Alvarez, C.; Godoy, Juan A.; Inestrosa, Nibaldo C.
    St. John's wort has been the subject of studies focused on its therapeutic properties against several diseases, including Alzheimer's disease (AD). Amyloid beta-peptide (A beta), a critical peptide in AD, has been linked to the mitochondrial dysfunction often observed in this disease. Despite many efforts to prevent A beta levels from increasing in AD, less has been done regarding the mitochondrial component. Therefore, we studied the effects of tetrahydrohyperforin (THH) on mitochondrial dysfunction of hippocampal neurons, challenged with A beta oligomers (A beta o) and A beta o-AChE complexes. We show that THH prevents mitochondrial calcium overload and induces the modulation of fusion-fission events, arresting mitochondrial dysfunction. Moreover, our results suggest that the modulation of mitochondrial dynamics probably occurs through a peroxisome proliferator-activated receptor gamma co-activator 1 alpha-mediated mechanism, inducing mitochondrial fusion-fission protein expression. Our results offer further explanation for the effects observed for THH and the beneficial effects of this ethno-botanical drug in AD.