Browsing by Author "Astudillo, Pablo"

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    Evidence for TGF-β1/Nrf2 Signaling Crosstalk in a Cuprizone Model of Multiple Sclerosis
    (2024) Guevara, Coram; Vicencio, Sinay C.; Pizarro, Ignacio S.; Villavicencio-Tejo, Francisca; Quintanilla, Rodrigo A.; Astudillo, Pablo; Ampuero, Estibaliz; Varas, Rodrigo; Orellana, Juan A.; Ortiz, Fernando C.
    Multiple sclerosis (MS) is a chronic and degenerative disease that impacts central nervous system (CNS) function. One of the major characteristics of the disease is the presence of regions lacking myelin and an oxidative and inflammatory environment. TGF-beta 1 and Nrf2 proteins play a fundamental role in different oxidative/inflammatory processes linked to neurodegenerative diseases such as MS. The evidence from different experimental settings has demonstrated a TGF-beta 1-Nrf2 signaling crosstalk under pathological conditions. However, this possibility has not been explored in experimental models of MS. Here, by using the cuprizone-induced demyelination model of MS, we report that the in vivo pharmacological blockage of the TGF-beta 1 receptor reduced Nrf2, catalase, and TGF beta-1 protein levels in the demyelination phase of cuprizone administration. In addition, ATP production, locomotor function and cognitive performance were diminished by the treatment. Altogether, our results provide evidence for a crosstalk between TGF-beta 1 and Nrf2 signaling pathways under CNS demyelination, highlighting the importance of the antioxidant cellular response of neurodegenerative diseases such as MS.
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    Interaction between Passive Filter and High Power Cycloconverter Drive
    (IEEE, 2009) Olivares, Cristhian; Astudillo, Pablo; Moran, Luis; Dixon Rojas, Juan
    This paper presents the study of dynamic interactions between passive filters and high power cycloconverters drives. The dynamic interaction considers the impact of connection and disconnection of passive filters operating in conjunction with high power cycloconverters. The inrush currents generated by filter connection affects the cycloconverter operation. The paper presents a detailed analysis based on results obtained from a real grinding mill plant with one SAG and two ball mill drives. The analysis presented in this paper includes the simulated model developed in MATLAB, transient analysis for connection and disconnection of the passive filter set, and recommendations to avoid transient interactions that affect cycloconverters drive operation.
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    'It would be a problem for the family': queerness, family honour and familism in Chile
    (2024) Ramm, Alejandra; Astudillo, Pablo; Venegas, Daniel; Dinamarca, Consuelo; Salinas, Viviana
    Family honour, protecting and upholding the family name, is central to familism. Yet, it has been somewhat neglected by scholarship on Latin American and Latino families. Familism involves prioritising the family over the individual. Likewise, the family of origin holds particular significance, offering material, social and emotional support, and shaping one's identity, honour and sense of belonging. Heteronormativity and patriarchy portray queer individuals as the causes of family shame. This study examined how family honour, as a component of familism, operates within kin dynamics, specifically focusing on same-sex cohabitation, as this living arrangement serves as a tangible expression of a non-normative sexual orientation. A life course perspective was used to study 24 cases of cohabiting lesbian, gay and bi/pansexual individuals in Chile. The results show the enduring significance of families in providing support, sociability, identity, and a sense of belonging. Nevertheless, it reveals notable instances of family rejection towards queer kin. In Chile, both families of origin and queer individuals employ subtle strategies to conceal their queerness, guided by notions of 'respect' associated with family honour and decency. These strategies involve unspoken agreements to maintain family bonds through discreet displays of queer behaviour without explicit acknowledgement of sexual identity.
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    Syndecan-4 inhibits Wnt/β-catenin signaling through regulation of low-density-lipoprotein receptor-related protein (LRP6) and R-spondin 3
    (2014) Astudillo, Pablo; Carrasco, Hector; Larrain, Juan
    Regulation of Wnt signaling is crucial for embryonic development and adult homeostasis. Here we study the role of Syndecan-4 (SDC4), a cell-surface heparan sulphate proteoglycan, and Fibronectin (FN), in Wnt/beta-catenin signaling. Gain- and loss-of-function experiments in mammalian cell lines and Xenopus embryos demonstrate that SDC4 and FN inhibit Wnt/beta-catenin signaling. Epistatic and biochemical experiments show that this inhibition occurs at the cell membrane level through regulation of LRP6. R-spondin 3, a ligand that promotes canonical and non-canonical Wnt signaling, is more prone to potentiate Wnt/beta-catenin signaling when SDC4 levels are reduced, suggesting a model whereby SDC4 tunes the ability of R-spondin to modulate the different Wnt signaling pathways. Since SDC4 has been previously related to non-canonical Wnt signaling, our results also suggest that this proteoglycan can be a key component in the regulation of Wnt signaling. (C) 2013 Elsevier Ltd. All rights reserved.