Browsing by Author "Diaz-Araya, Guillermo"

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    Fibroblast Primary Cilia Are Required for Cardiac Fibrosis
    (2019) Villalobos, Elisa; Criollo, Alfredo; Schiattarella, Gabriele G.; Altamirano, Francisco; French, Kristin M.; May, Herman, I; Jiang, Nan; Ngoc Uyen Nhi Nguyen; Romero, Diego; Carlos Roa, Juan; Garcia, Lorena; Diaz-Araya, Guillermo; Morselli, Eugenia; Ferdous, Anwarul; Conway, Simon J.; Sadek, Hesham A.; Gillette, Thomas G.; Lavandero, Sergio; Hill, Joseph A.
    BACKGROUND: The primary cilium is a singular cellular structure that extends from the surface of many cell types and plays crucial roles in vertebrate development, including that of the heart. Whereas ciliated cells have been described in developing heart, a role for primary cilia in adult heart has not been reported. This, coupled with the fact that mutations in genes coding for multiple ciliary proteins underlie polycystic kidney disease, a disorder with numerous cardiovascular manifestations, prompted us to identify cells in adult heart harboring a primary cilium and to determine whether primary cilia play a role in disease-related remodeling.
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    Gln(27)-> Glu beta(2)-Adrenergic Receptor Polymorphism in Heart Failure Patients: Differential Clinical and Oxidative Response to Carvedilol
    (2009) Troncoso, Rodrigo; Moraga, Francisco; Chiong, Mario; Roldán Saelzer, Juan; Bravo, Roberto; Valenzuela Bassi, Rodrigo Andrés; Diaz-Araya, Guillermo; Del Campo, Andrea; Sanhueza, Carlos; Rodriguez, Andrea; Vukasovic, Jose Luis; Mellado Suazo, Rosemarie; Greig, Douglas; Castro Gálvez, Pablo Federico
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    Hyperosmotic stress-dependent NFκB activation is regulated by reactive oxygen species and IGF-1 in cultured cardiomyocytes
    (2006) Eisner, Veronica; Criollo, Alfredo; Quiroga, Clara; Olea-Azar, Claudio; Santibanez, Juan Francisco; Troncoso, Rodrigo; Chiong, Mario; Diaz-Araya, Guillermo; Foncea, Rocio; Lavandero, Sergio
    We have recently shown that hyperosmotic stress activates p65/RelB NF kappa B in cultured cardiomyocytes with dichotomic actions on caspase activation and cell death. It remains unexplored how NFKB is regulated in cultured rat cardiomyocytes exposed to hyperosmotic stress. We study here: (a) if hyperosmotic stress triggers reactive oxygen species (ROS) generation and in turn whether they regulate NFKB and (b) if insulin-like growth factor-1 (IGF-1) modulates ROS production and NF kappa B activation in hyperosmotically-stressed cardiomyocytes. The results showed that hyperosmotic stress generated ROS in cultured cardiac myocytes, in particular the hydroxyl and superoxide species, which were inhibited by N-acetylcysteine (NAC). Hyperosmotic stress-induced NFKB activation as determined by I kappa B alpha degradation and NF kappa B DNA binding. NFKB activation and procaspase-3 and -9 fragmentation were prevented by NAC and IGF-1. However, this growth factor did not decrease ROS generation induced by hyperosmotic stress, suggesting that its actions over NFKB and caspase activation may be due to modulation of events downstream of ROS generation. We conclude that hyperosmotic stress induces ROS, which in turn activates NF kappa B and caspases. IGF-1 prevents NFKB activation by a ROS-independent mechanism. (c) 2006 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
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    Interferon-β decreases LPS-induced neutrophil recruitment to cardiac fibroblasts
    (2023) Anfossi, Renatto; Vivar, Raul; Ayala, Pedro; Gonzalez-Herrera, Fabiola; Espinoza-Perez, Claudio; Osorio, Jose Miguel; Roman-Torres, Mauricio; Bolivar, Samir; Diaz-Araya, Guillermo
    Introduction: Cardiac fibroblasts (CF) are crucial cells in damaged heart tissues, expressing TLR4, IFN-receptor and responding to lipopolysaccharide (LPS) and interferon-beta (IFN-beta) respectively. While CF interact with immune cells; however, their relationship with neutrophils remains understudied. Additionally, theimpact of LPS and IFN-beta on CF-neutrophil interaction is poorly understood.Methods: Isolated CF from adult rats were treated with LPS, with or without IFN-beta. This study examined IL-8 secretion, ICAM-1 and VCAM-1 expression, and neutrophil recruitment, as well as their effects on MMPs activity.Results: LPS triggered increased IL-8 expression and secretion, along with elevated ICAM-1 and VCAM-1 expression, all of which were blocked by TAK-242. Pre-treatment with IFN-beta countered these LPS effects. LPS treated CF showed higher neutrophil recruitment (migration and adhesion) compared to unstimulated CF, an effect prevented by IFN-beta. Ruxolitinib blocked these IFN-beta anti-inflammatory effects, implicating JAK signaling. Analysis of culture medium zymograms from CF alone, and CF-neutrophils interaction, revealed that MMP2 was mainly originated from CF, while MMP9 could come from neutrophils. LPS and IFN-beta boosted MMP2 secretion by CF. MMP9 activity in CF was low, and LPS or IFN-beta had no significant impact. Pre-treating CF with LPS, IFN-beta, or both before co-culture with neutrophils increased MMP2. Neutrophil co-culture increased MMP9 activity, with IFN-beta pre-treatment reducing MMP9 compared to unstimulated CF.Conclusion: In CF, LPS induces the secretion of IL-8 favoring neutrophils recruitment and these effects were blocked by IFN-. The results highlight that CF-neutrophil interaction appears to influence the extracellular matrix through MMPs activity modulation.
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    Interleukin 33/ST2 Axis Components Are Associated to Desmoplasia, a Metastasis-Related Factor in Colorectal Cancer
    (2019) Landskron, Glauben; De la Fuente Lopez, Marjorie; Dubois-Camacho, Karen; Diaz-Jimenez, David; Orellana-Serradell, Octavio; Romero, Diego; Sepulveda, Santiago A.; Salazar, Christian; Parada-Venegas, Daniela; Quera, Rodrigo; Simian, Daniela; Gonzalez, Maria-Julieta; Kronberg, Udo; Abedrapo, Mario; Gallegos, Ivan; Contreras, Hector R.; Pena, Cristina; Diaz-Araya, Guillermo; Carlos Roa, Juan; Hermoso, Marcela A.
    In colorectal cancer (CRC), cancer-associated fibroblasts (CAFs) are the most abundant component from the tumor microenvironment (TM). CAFs facilitate tumor progression by inducing angiogenesis, immune suppression and invasion, thus altering the organization/composition of the extracellular matrix (i.e., desmoplasia) and/or activating epithelial-mesenchymal transition (EMT). Soluble factors from the TM can also contribute to cell invasion through secretion of cytokines and recently, IL-33/ST2 pathway has gained huge interest as a protumor alarmin, promoting progression to metastasis by inducing changes in TM. Hence, we analyzed IL-33 and ST2 content in tumor and healthy tissue lysates and plasma from CRC patients. Tissue localization and distribution of these molecules was evaluated by immunohistochemistry (using localization reference markers a-smooth muscle actin or alpha-SMA and E-cadherin), and clinical/histopathological information was obtained from CRC patients. In vitro experiments were conducted in primary cultures of CAFs and normal fibroblasts (NFs) isolated from tumor and healthy tissue taken from CRC patients. Additionally, migration and proliferation analysis were performed in HT29 and HCT116 cell lines. It was found that IL-33 content increases in left-sided CRC patients with lymphatic metastasis, with localization in tumor epithelia associated with abundant desmoplasia. Although ST2 content showed similarities between tumor and healthy tissue, a decreased immunoreactivity was observed in left-sided tumor stroma, associated to metastasis related factors (advanced stages, abundant desmoplasia, and presence of tumor budding). A principal component analysis (including stromal and epithelial IL-33/ST2 and alpha-SMA immunoreactivity with extent of desmoplasia) allowed us to distinguish clusters of low, intermediate and abundant desmoplasia, with potential to develop a diagnostic signature with benefits for further therapeutic targets. IL-33 transcript levels from CAFs directly correlated with CRC cell line migration induced by CAFs conditioned media, with rhlL-33 inducing a mesenchymal phenotype in HT29 cells. These results indicate a role of IL-33/ST2 in tumor microenvironment, specifically in the interaction between CAFs and epithelial tumor cells, thus contributing to invasion and metastasis in left-sided CRC, most likely by activating desmoplasia.
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    Toll-Like Receptor 4 Activation Prevents Rat Cardiac Fibroblast Death Induced by Simulated Ischemia/Reperfusion
    (2021) Parra-Flores, Pablo; Espitia-Corredor, Jenaro; Espinoza-Perez, Claudio; Queirolo, Cristian; Ayala, Pedro; Bruggendieck, Francisca; Salas-Hernandez, Aimee; Pardo-Jimenez, Viviana; Diaz-Araya, Guillermo
    Death of cardiac fibroblasts (CFs) by ischemia/reperfusion (I/R) has major implications for cardiac wound healing. In in vivo models of myocardial infarction, toll-like receptor 4 (TLR4) activation has been reported as a cardioprotector; however, it remains unknown whether TLR4 activation can prevent CF death triggered by simulated I/R (sI/R). In this study, we analyzed TLR4 activation in neonate CFs exposed to an in vitro model of sI/R and explored the participation of the pro-survival kinases Akt and ERK1/2. Simulated ischemia was performed in a free oxygen chamber in an ischemic medium, whereas reperfusion was carried out in normal culture conditions. Cell viability was analyzed by trypan blue exclusion and the MTT assay. Necrotic and apoptotic cell populations were evaluated by flow cytometry. Protein levels of phosphorylated forms of Akt and ERK1/2 were analyzed by Western blot. We showed that sI/R triggers CF death by necrosis and apoptosis. In CFs exposed only to simulated ischemia or only to sI/R, blockade of the TLR4 with TAK-242 further reduced cell viability and the activation of Akt and ERK1/2. Preconditioning with lipopolysaccharide (LPS) or treatment with LPS in ischemia or reperfusion was not protective. However, LPS incubation during both ischemia and reperfusion periods prevented CF viability loss induced by sI/R. Furthermore, LPS treatment reduced the sub-G1 population, but not necrosis of CFs exposed to sI/R. On the other hand, the protective effects exhibited by LPS were abolished when TLR4 was blocked and Akt and ERK1/2 were inhibited. In conclusion, our results suggest that TLR4 activation protects CFs from apoptosis induced by sI/R through the activation of Akt and ERK1/2 signaling pathways.