Browsing by Author "Castro, Juan"

Now showing 1 - 11 of 11
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    C(-106)T polymorphism of the aldose reductase gene and the progression rate of diabetic retinopathy
    (ELSEVIER IRELAND LTD, 2006) Olmos, Pablo; Bastias, Maria Juliana; Vollrath, Valeska; Toro, Luis; Trincado, Arturo; Salinas, Pablo; Claro, Juan Carlos; Lopez, Jose Manuel; Acosta, Ana Maria; Miquel, Juan Francisco; Castro, Juan
    Purpose: To study the C(-106)T polymorphism in the promoter of the aldose reductase (ALR2) gene: (a) its local prevalence and (b) its modulation of the susceptibility for developing retinopathy.
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    c-Abl Activation Linked to Autophagy-Lysosomal Dysfunction Contributes to Neurological Impairment in Niemann-Pick Type A Disease
    (2022) Marin, Tamara; Dulcey, Andres E.; Campos, Fabian; de la Fuente, Catalina; Acuna, Mariana; Castro, Juan; Pinto, Claudio; Yanez, Maria Jose; Cortez, Cristian; McGrath, David W.; Saez, Pablo J.; Gorshkov, Kirill; Zheng, Wei; Southall, Noel; Carmo-Fonseca, Maria; Marugan, Juan; Alvarez, Alejandra R.; Zanlungo, Silvana
    Niemann-Pick type A (NPA) disease is a fatal lysosomal neurodegenerative disorder caused by the deficiency in acid sphingomyelinase (ASM) activity. NPA patients present severe and progressive neurodegeneration starting at an early age. Currently, there is no effective treatment for this disease and NPA patients die between 2 and 3 years of age. NPA is characterized by an accumulation of sphingomyelin in lysosomes and dysfunction in the autophagy-lysosomal pathway. Recent studies show that c-Abl tyrosine kinase activity downregulates autophagy and the lysosomal pathway. Interestingly, this kinase is also activated in other lysosomal neurodegenerative disorders. Here, we describe that c-Abl activation contributes to the mechanisms of neuronal damage and death in NPA disease. Our data demonstrate that: 1) c-Abl is activated in-vitro as well as in-vivo NPA models; 2) imatinib, a clinical c-Abl inhibitor, reduces autophagy-lysosomal pathway alterations, restores autophagy flux, and lowers sphingomyelin accumulation in NPA patient fibroblasts and NPA neuronal models and 3) chronic treatment with nilotinib and neurotinib, two c-Abl inhibitors with differences in blood-brain barrier penetrance and target binding mode, show further benefits. While nilotinib treatment reduces neuronal death in the cerebellum and improves locomotor functions, neurotinib decreases glial activation, neuronal disorganization, and loss in hippocampus and cortex, as well as the cognitive decline of NPA mice. Our results support the participation of c-Abl signaling in NPA neurodegeneration and autophagy-lysosomal alterations, supporting the potential use of c-Abl inhibitors for the clinical treatment of NPA patients.
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    Deficiency of Niemann-Pick C1 protein protects against diet-induced gallstone formation in mice
    (2010) Morales France, María Gabriela; Amigo Böker, Ludwig Peter; Balboa Castillo, Elisa Ivana; Acuña Aravena, Mariana Loreto; Castro, Juan; Molina, Héctor; Miquel P., Juan Francisco; Nervi, Flavio; Rigotti Rivera, Attilio; Zanlungo Matsuhiro, Silvana
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    Dermoscopy of linear basal cell carcinomas, a potential mimicker of linear lesions: a descriptive case series
    (2022) Navarrete-Dechent, Cristián; Marchetti, Michael; Uribe González, Pablo Francisco; Schwartz, Rodrigo; Liopyris, Konstantinos; Marghoob, Nadeem; Galimany Navajas, Lucas Fernando; Castro, Juan; Jaimes, Natalia; Rabinovitz, Harold; Moraes, Ana; Marghoob, Ashfaq; Abarzúa-Araya, Alvaro
    Introduction: Among the various widely recognized basal cell carcinoma (BCC) clinical patterns, linear basal cell carcinoma (LBCC) is an uncommon morphologic variant of BCC. Objectives: Describe the clinical and dermoscopic characteristics of LBCC. Methods: Retrospective study including LBCC cases from 5 dermatology centers in North and South America. Biopsy-proven primary BCCs, that presented with at least 3:1 length:width ratio on physical examination, irrespective of tumor subtype or location, were included. Clinical and dermoscopic analysis were performed by 2 experts in dermoscopy. Results: Eighteen cases of LBCC met our inclusion criteria and were included in the study. Median age at diagnosis was 86.0 years, 10 patients (58.8%) were males. Regarding anatomic location, 11/18.
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    Imatinib therapy blocks cerebellar apoptosis and improves neurological symptoms in a mouse model of Niemann-Pick type C disease
    (WILEY, 2008) Alvarez, Alejandra R.; Klein, Andres; Castro, Juan; Cancino, Gonzalo I.; Amigo, Julio; Mosqueira, Matias; Vargas, Lina M.; Yevenes, L. Fernanda; Bronfman, Francisca C.; Zanlungo, Silvana
    Niemann-Pick type C (NPC) disease is a fatal autosomal recessive disorder characterized by the accumulation of free cholesterol and glycosphingo-lipids in the endosomal-lysosomal system. Patients with NPC disease have markedly progressive neuronal loss, mainly of cerebellar Purkinje neurons. There is strong evidence indicating that cholesterol accumulation and trafficking defects activate apoptosis in NPC brains. The purpose of this study was to analyze the relevance of apoptosis and particularly the proapoptotic c-Abl/p73 system in cerebellar neuron degeneration in NPC disease. We used the NPC1 mouse model to evaluate c-Abl/p73 expression and activation in the cerebellum and the effect of therapy with the c-Abl-specific inhibitor imatinib. The proapoptotic c-Abl/p73 system and the p73 target genes are expressed in the cerebellums of NPC mice. Furthermore, inhibition of c-Abl with imatinib preserved Purkinje neurons and reduced general cell apoptosis in the cerebellum, improved neurological symptoms, and increased the survival of NPC mice. Moreover, this prosurvival effect correlated with reduced mRNA levels of p73 proapoptotic target genes. Our results suggest that the c-Abl/p73 pathway is involved in NPC neurodegeneration and show that treatment with c-Abl inhibitors is useful in delaying progressive neurodegeneration, supporting the use of imatinib for clinical treatment of patients with NPC disease.
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    Inactivation of hepatic microsomal triglyceride transfer protein protects mice from diet-induced gallstones
    (W B SAUNDERS CO-ELSEVIER INC, 2006) Amigo, Ludwig; Castro, Juan; Miquel, Juan Francisco; Zanlungo, Silvana; Young, Stephen G.; Nervi, Flavio
    Background & Aims: Microsomal triglyceride transfer protein (MTTP) is critical for the production of very-low-density lipoproteins (VLDL). The current studies were undertaken to examine the in vivo role of MTTP in hepatic cholesterol and fatty acid metabolism, as well as in biliary lipid secretion. We also tested whether MTTP plays a role in diet-induced cholelithiasis in mice. Methods: We used mice in which Mttp had been inactivated in the liver (Mttp(Delta/Delta) mice). We measured several parameters of cholesterol metabolism, fatty acid synthesis, and biliary lipid levels in mice fed a normal or a lithogenic diet. We also assessed the incidence of diet-associated gallstones. Results: Hepatic Mttp inactivation markedly decreased plasma triglyceride and cholesterol levels and increased biliary cholesterol and bile acid output. Hepatic cholesterogenesis and fatty acid synthesis were significantly decreased in Mttp(Delta/Delta), mice compared with control mice. The incidence of gallstones decreased from 90% in control mice to 33% in Mttp(Delta/Delta) mice after 8 weeks of a lithogenic diet (P < .0001). The mechanism of the protective effect appears to be increased biliary phospholipid output in Mttp(Delta/Delta) mice, leading to significant unsaturation of gallbladder bile. Conclusions: These results indicate that modulation of Map expression in the liver affects hepatic lipid svnthesis and storage as well as biliary lipid secretion. Our findings further indicate that inhibition of hepatic MTTP activity decreases the risk of experimental cholelithiasis by favoring phospholipid output into the bile.
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    Increased activity of hepatic microsomal triglyceride transfer protein and bile acid synthesis in gallstone disease
    (JOHN WILEY & SONS INC, 2007) Castro, Juan; Amigo, Ludwig; Miquel, Juan Francisco; Galman, Cecilia; Crovari, Fernando; Raddatz, Alejandro; Zanlungo, Silvana; Jalil, Roberto; Rudling, Mats; Nervi, Flavio
    A strong interrelationship exists between the regulation of bile acid (BA) metabolism and hepatic very low density lipoprotein (VLDL) production. We have recently shown that BA synthesis is increased in gallstone disease. We investigated the activity of hepatic microsomal triglyceride transfer protein (MTTP) as a surrogate of VLDL production, BA synthesis, and mRNA expression levels of proteins that regulate fatty acid (FA) metabolism in the liver of gallstone (GS) patients compared with GS-free patients. Twenty-seven volunteers subjected to elective surgery; 9 were GS-free and 18 with GS agreed to have a liver biopsy. We quantified by a fluorescence assay the activity of MTTP and by quantitative reverse-transcription PCR (RT-PCR) the mRNA content of hepatic MTTP and genes that regulate hepatic sterol and FA metabolism. Plasma was assayed for lathosterol and 7 alpha-hydroxy-4-cholesten-3-one. Liver histology was normal in GS and GS-free patients. Serum VLDL triglycerides and apoB were significantly increased in GS. Hepatic triglycerides tripled in GS (P < 0.001) compared with GS-free. MTTP activity increased 70% (P < 0.001). Serum lathosterol and hepatic cholesterol concentrations, and mRNA expressions of MTTP, CD36, and FABP1 were similar in GS-free and GS patients. Hepatic mRNA expression of hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR) and 3-hydroxyl-3-methyl-glutaryl-CoA synthase (HMGS) were significantly decreased- 40% and 27%, respectively in GS. Serum 7a-hydroxy-4-cholesten-3-one was 75% higher, and mRNA expression of CYP7A1 was increased sevenfold (P < 0.001) in GS. Conclusion: Hepatic MTTP activity and BA synthesis are increased in GS. Results suggest that hepatic VLDL production and trafficking of BA are increased in gallstone patients.
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    Niemann-Pick C2 Protein Expression Regulates Lithogenic Diet-Induced Gallstone Formation and Dietary Cholesterol Metabolism in Mice
    (SPRINGER HEIDELBERG, 2012) Balboa, Elisa; Morales, Gabriela; Aylwin, Paula; Carrasco, Gonzalo; Amigo, Ludwig; Castro, Juan; Rigotti, Attilio; Zanlungo, Silvana
    Niemann-Pick C2 protein (NPC2) is a lysosomal soluble protein that is highly expressed in the liver; it binds to cholesterol and is involved in intracellular cholesterol trafficking, allowing the exit of lysosomal cholesterol obtained via the lipoprotein endocytic pathway. Thus, this protein may play an important role in controlling hepatic cholesterol transport and metabolism. The aim of this work was to study the relevance of NPC2 protein expression in hepatic cholesterol metabolism, biliary lipid secretion and gallstone formation by comparing NPC2 hypomorph [NPC2 (h/h)] and wild-type mice fed control, 2% cholesterol, and lithogenic diets. NPC2 (h/h) mice exhibited resistance to a diet-induced increase in plasma cholesterol levels. When consuming the chow diet, we observed increased biliary cholesterol and phospholipid secretions in NPC2 (h/h) mice. When fed the 2% cholesterol diet, NPC2 (h/h) mice exhibited low and high gallbladder bile cholesterol and phospholipid concentrations, respectively. NPC2 (h/h) mice fed with the lithogenic diet showed reduced biliary cholesterol secretion, gallbladder bile cholesterol saturation, and cholesterol crystal and gallstone formation. This work indicates that hepatic NPC2 expression is an important factor in the regulation of diet-derived cholesterol metabolism and disposal as well as in diet-induced cholesterol gallstone formation in mice.
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    Spermatozoa from mice deficient in Niemann-Pick disease type C2 (NPC2) protein have defective cholesterol content and reduced in vitro fertilising ability
    (2014) Busso, Dolores; Oñate Alvarado, María José; Balboa Castillo, Elisa Ivana; Castro, Juan; Lizama, Carlos; Morales, Gabriela; Vargas, Susana; Härtel, Steffen; Moreno Mauro, Ricardo D.; Zanlungo Matsuhiro, Silvana
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    Structural and functional analysis of the ASM p.Ala359Asp mutant that causes acid sphingomyelinase deficiency
    (2016) Acuña, Mariana; Castro Fernández, Víctor; Latorre, Mauricio; Castro, Juan; Schuchman, Edward H.; Guixé, Victoria; González, Mauricio; Zanlungo Matsuhiro, Silvana
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    Transgenic overexpression of Niemann-Pick C2 protein promotes cholesterol gallstone formation in mice
    (2016) Acuña, Mariana; González Hódar, Lila Alejandra; Amigo, Ludwig; Castro, Juan; Morales, M. Gabriela; Cancino, Gonzalo I.; Groen, Albert K.|Young, Juan; Miquel P., Juan Francisco; Zanlungo Matsuhiro, Silvana