Millennium Institute of Immunology and Immunotherapy

Santiago, Chile

Millennium Institute of Immunology and Immunotherapy

Santiago, Chile
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Rojas F.,Andrés Bello University | Gonzalez D.,Andrés Bello University | Cortes N.,Andrés Bello University | Ampuero E.,Andrés Bello University | And 9 more authors.
Frontiers in Cellular Neuroscience | Year: 2015

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease in which pathogenesis and death of motor neurons are triggered by non-cell-autonomous mechanisms. We showed earlier that exposing primary rat spinal cord cultures to conditioned media derived from primary mouse astrocyte conditioned media (ACM) that express human SOD1G93A(ACM-hSOD1G93A) quickly enhances Nav channel- mediated excitability and calcium influx, generates intracellular reactive oxygen species (ROS), and leads to death of motoneurons within days. Here we examined the role of mitochondrial structure and physiology and of the activation of c-Abl, a tyrosine kinase that induces apoptosis. We show that ACM-hSOD1G93A, but not ACM-hSOD1WT, increases c-Abl activity in motoneurons, interneurons and glial cells, starting at 60 min; the c-Abl inhibitor STI571 (imatinib) prevents this ACM-hSOD1G93A-mediated motoneuron death. Interestingly, similar results were obtained with ACM derived from astrocytes expressing SOD1G86Ror TDP43A315T. We further find that co-application of ACM-SOD1G93Awith blockers of Nav channels (spermidine, mexiletine, or riluzole) or anti-oxidants (Trolox, esculetin, or tiron) effectively prevent c-Abl activation and motoneuron death. In addition, ACM-SOD1G93Ainduces alterations in the morphology of neuronal mitochondria that are related with their membrane depolarization. Finally, we find that blocking the opening of the mitochondrial permeability transition pore with cyclosporine A, or inhibiting mitochondrial calcium uptake with Ru360, reduces ROS production and c-Abl activation. Together, our data point to a sequence of events in which a toxic factor(s) released by ALS-expressing astrocytes rapidly induces hyper-excitability, which in turn increases calcium influx and affects mitochondrial structure and physiology. ROS production, mediated at least in part through mitochondrial alterations, trigger c-Abl signaling and lead to motoneuron death. © 2015 Rojas,Gonzalez,Cortes


Hajmousa G.,University of Groningen | Elorza A.A.,Millennium Institute of Immunology and Immunotherapy | Elorza A.A.,Andrés Bello University | Nies V.J.M.,University of Groningen | And 3 more authors.
Stem Cells and Development | Year: 2016

Diabetic retinopathy (DR) is a hyperglycemia (HG)-mediated microvascular complication. In DR, the loss of pericytes and subsequently endothelial cells leads to pathologic angiogenesis in retina. Adipose-derived stromal cells (ASC) are a promising source of therapeutic cells to replace lost pericytes in DR. To date, knowledge of the influence of HG on the bioenergetics and pericytic function of ASC is negligible. Human ASC were cultured in normoglycemia medium (5 mM d-glucose) or under HG (30 mM d-glucose) and assessed. Our data showed that HG increased the level of apoptosis and reactive oxygen species production in ASC, yet their proliferation rate was not affected. HG induced alterations in mitochondrial function and morphology in ASC. HG also strongly affected the bioenergetic status of ASC in which both the maximum oxygen consumption rate and extracellular acidification rate were decreased. This was corroborated by a reduced uptake of glucose under HG. In spite of these observations, in vitro, ASC promoted the formation of vascular-like networks of human umbilical vein endothelial cells on monolayers of ASC under HG with minimally affected. © 2016, Mary Ann Liebert, Inc.


Ruiz L.M.,Andrés Bello University | Ruiz L.M.,Autonomous University of Chile | Jensen E.L.,Andrés Bello University | Bustos R.I.,Andrés Bello University | And 12 more authors.
Journal of Cellular Physiology | Year: 2014

Copper is an essential cofactor of complex IV of the electron transfer chain, and it is directly involved in the generation of mitochondrial membrane potential. Its deficiency induces the formation of ROS, large mitochondria and anemia. Thus, there is a connection between copper metabolism and bioenergetics, mitochondrial dynamics and erythropoiesis. Copper depletion might end in cellular apoptosis or necrosis. However, before entering into those irreversible processes, mitochondria may execute a series of adaptive responses. Mitochondrial adaptive responses (MAR) may involve multiple and diverse mechanisms for preserving cell life, such as mitochondrial dynamics, OXPHOS remodeling and bioenergetics output. In this study, a mild copper deficiency was produced in an animal model through intraperitoneal injections of bathocuproine disulfonate in order to study the MAR. Under these conditions, a new type of mitochondrial morphology was discovered in the liver. Termed the "butternut squash" mitochondria, it coexisted with normal and swollen mitochondria. Western blot analyses of mitochondrial dynamics proteins showed an up-regulation of MFN-2 and OPA1 fusion proteins. Furthermore, isolated liver mitochondria displayed OXPHOS remodeling through a decrease in supercomplex activity with a concomitant increase at an individual level of complexes I and IV, higher respiratory rates at complex I and II levels, higher oligomycin-insensitive respiration, and lower respiratory control ratio values when compared to the control group. As expected, total ATP and ATP/ADP values were not significantly different, since animal's health was not compromised. As a whole, these results describe a compensatory and adaptive response of metabolism and bioenergetics under copper deprivation. © 2013 Wiley Periodicals, Inc.


Carvajal C.A.,University of Santiago de Chile | Carvajal C.A.,Millennium Institute of Immunology and Immunotherapy | Campino C.,University of Santiago de Chile | Campino C.,Millennium Institute of Immunology and Immunotherapy | And 13 more authors.
Hypertension | Year: 2012

Familial hyperaldosteronism type I is caused by an unequal crossover of 11β-hydroxylase (CYP11B1) and aldosterone synthase (CYP11B2) genes, giving rise to a chimeric CYP11B1/CYP11B2 gene (CG). We describe a family carrying a CG with high levels of free 18-hydroxycortisol but low prevalence of primary aldosteronism (PA) and an atypical CG inheritance pattern in a family of 4 generations with 16 adults and 13 children, we measured the arterial blood pressure, serum aldosterone, and plasma renin activity and then calculated the serum aldosterone:plasma renin activity ratio and urinary free 18-hydroxycortisol. We identified the CG by long-extension PCR and predicted its inheritance pattern. The CG was found in 24 of 29 subjects (10 children and 14 adults). In CG+ patients, hypertension and high 18-hydroxycortisol were prevalent (83% and 100%, respectively). High serum aldosterone:plasma renin activity ratio was more frequent in pediatric than adult patients (80% versus 36%; P<0.001). An inverse association between serum aldosterone:plasma renin activity ratio and age was observed (r=-0.48; P=0.018). Sequence analysis identified the CYP11B1/CYP11B2 crossover in a 50-bp region spanning intron 3 of CYP11B1 and exon 4 of CYP11B2. The CG segregation differs from an autosomal disease, showing 100% of CG penetrance in generations II and III. Statistical analysis suggests that inheritance pattern was not attributed to random segregation (P<0.001). In conclusion, we describe a family with an atypical CYP11B1/CYP11B2 gene inheritance pattern and variable phenotypic expression, where the majority of pediatric patients have primary aldosteronism. Most adults have normal aldosterone and renin levels, which could mask them as essential hypertensives. © 2011 American Heart Association, Inc.


Ruiz L.M.,Autonomous University of Chile | Salazar C.,Autonomous University of Chile | Jensen E.,Andrés Bello University | Ruiz P.A.,IEng Solutions Ltd. | And 5 more authors.
Oxidative Medicine and Cellular Longevity | Year: 2015

Quercetin, a dietary flavonoid used as a food supplement, showed powerful antioxidant effects in different cellular models. However, recent in vitro and in vivo studies in mammals have suggested a prooxidant effect of quercetin and described an interaction with mitochondria causing an increase in O2- production, a decrease in ATP levels, and impairment of respiratory chain in liver tissue. Therefore, because of its dual actions, we studied the effect of quercetin in vivo to analyze heart mitochondrial function and erythropoiesis. Mice were injected with 50 mg/kg of quercetin for 15 days. Treatment with quercetin decreased body weight, serum insulin, and ceruloplasmin levels as compared with untreated mice. Along with an impaired antioxidant capacity in plasma, quercetin-treated mice showed a significant delay on erythropoiesis progression. Heart mitochondrial function was also impaired displaying more protein oxidation and less activity for IV, respectively, than no-treated mice. In addition, a significant reduction in the protein expression levels of Mitofusin 2 and Voltage-Dependent Anion Carrier was observed. All these results suggest that quercetin affects erythropoiesis and mitochondrial function and then its potential use as a dietary supplement should be reexamined. © 2015 Lina M. Ruiz et al.


Tapia-Castillo A.,University of Santiago de Chile | Carvajal C.A.,University of Santiago de Chile | Carvajal C.A.,Millennium Institute of Immunology and Immunotherapy | Campino C.,University of Santiago de Chile | And 17 more authors.
American Journal of Hypertension | Year: 2014

Background:The GTPase Rac1 has been implicated in hypertension as a modulator of mineralocorticoid receptor activity. Our aim is to investigate the frequency of polymorphisms rs10951982 (intron 1, G>A) and rs836478 (intron 3, T>C) in the RAC1 gene and perform association studies with clinical and biochemical parameters in a Chilean pediatric cohort.Methods:Two hundred two normotensive (NT) subjects (aged 4-16 years) were divided into 2 groups: NT subjects with hypertensive parents (NH; n = 103) and NT subjects with NT parents (NN; n = 99). We measured markers of inflammation (high-sensitivity C-reactive protein, interleukin 6 (IL-6), interleukin 8, and tumor necrosis factor α), endothelial damage (Plasminogen activator inhibitor-1 metalloproteinase-9, and metalloproteinase-2), and oxidative stress (malondialdehyde). Data were expressed as median and interquartile range (IQR).Results:We found differences in polymorphism rs836478 (intron 3, C>T) in both genotypic (χ2 = 15.2, 2df; P = 0.0005) and allelic (X2=5.5, 1df; P = 0.01) frequencies in NH vs. NN subjects. NH subjects with a TT genotype showed increase MMP9 expression (median = 2.3, IQR-1.6-3.2; vs. median = 1.6, IQR = 1.6-2.3 AU; P = 0.01) and lower IL-6 expression (median = 8.8, IQR = 7.0-11.8; vs. median = 12.1, IQR = 8.2-14.7 pg/ml; P = 0.02) compared with subjects with TC/CC genotype. No difference in the allelic frequency distribution was seen in the polymorphism rs10951982 (NH vs. NN: χ2=0.2, 1df; P = 0.6). For this SNP, NN subjects with GA/AA genotype showed decreased diastolic BP indexes compared with subjects with native GG genotype (median = 1.08, IQR = 1.0-1.2; vs. median = 0.99, IQR = 0.94-1.1; P = 0.02).Conclusions:We report the frequency of polymorphisms rs836478 and rs10951982 of the RAC1 gene in a Spanish-Amerindian cohort. The polymorphism rs836478 was associated with an increased expression in markers of inflammation and endothelial damage (MMP9 and IL-6) in pediatric subjects with a hypertensive genetic Background:. © 2014 American Journal of Hypertension, Ltd.


Gomez R.S.,Millennium Institute of Immunology and Immunotherapy | Gomez R.S.,French Institute of Health and Medical Research | Guisle-Marsollier I.,French Institute of Health and Medical Research | Bohmwald K.,Millennium Institute of Immunology and Immunotherapy | And 5 more authors.
Immunology Letters | Year: 2014

Human Respiratory Syncytial Virus (hRSV) is the leading cause of lower respiratory tract diseases, affecting particularly newborns and young children. This virus is able to modulate the immune response, generating a pro-inflammatory environment in the airways that causes obstruction and pulmonary alterations in the infected host. To date, no vaccines are available for human use and the first vaccine that reached clinical trials produced an enhanced hRSV-associated pathology 50 years ago, resulting in the death of two children. Currently, only two therapeutic approaches have been used to treat hRSV infection in high risk children: 1. Palivizumab, a humanized antibody against the F glycoprotein that reduces to half the number of hospitalized cases and 2. Ribavirin, which fails to have a significant therapeutic effect. A major caveat for these approaches is their high economical cost, which highlights the need of new and affordable therapeutic or prophylactic tools to treat or prevents hRSV infection. Accordingly, several efforts are in progress to understand the hRSV-associated pathology and to characterize the immune response elicited by this virus. Currently, preclinical and clinical trials are being conducted to evaluate safety and efficacy of several drugs and vaccines, which have shown promising results. In this article, we discuss the most important advances in the development of drugs and vaccines, which could eventually lead to better strategies to treat or prevent the detrimental inflammation triggered by hRSV infection. © 2014 Elsevier B.V.


Bustos R.I.,Andrés Bello University | Jensen E.L.,Andrés Bello University | Ruiz L.M.,Andrés Bello University | Rivera S.,Andrés Bello University | And 8 more authors.
Biochemical and Biophysical Research Communications | Year: 2013

Copper is essential in cell physiology, participating in numerous enzyme reactions. In mitochondria, copper is a cofactor for respiratory complex IV, the cytochrome c oxidase. Low copper content is associated with anemia and the appearance of enlarged mitochondria in erythropoietic cells. These findings suggest a connection between copper metabolism and bioenergetics, mitochondrial dynamics and erythropoiesis, which has not been explored so far. Here, we describe that bathocuproine disulfonate-induced copper deficiency does not alter erythropoietic cell proliferation nor induce apoptosis. However it does impair erythroid differentiation, which is associated with a metabolic switch between the two main energy-generating pathways. That is, from mitochondrial function to glycolysis. Switching off mitochondria implies a reduction in oxygen consumption and ROS generation along with an increase in mitochondrial membrane potential. Mitochondrial fusion proteins MFN2 and OPA1 were up-regulated along with the ability of mitochondria to fuse. Morphometric analysis of mitochondria did not show changes in total mitochondrial biomass but rather bigger mitochondria because of increased fusion. Similar results were also obtained with human CD34+, which were induced to differentiate into red blood cells. In all, we have shown that adequate copper levels are important for maintaining proper mitochondrial function and for erythroid differentiation where the energy metabolic switch plus the up-regulation of fusion proteins define an adaptive response to copper deprivation to keep cells alive. © 2013 Elsevier Inc.


Ruiz L.M.,Andrés Bello University | Ruiz L.M.,Autonomous University of Chile | Jensen E.L.,Andrés Bello University | Rossel Y.,Andrés Bello University | And 8 more authors.
Mitochondrion | Year: 2016

Copper is integral to the mitochondrial respiratory complex IV and contributes to proliferation and differentiation, metabolic reprogramming and mitochondrial function. The K562 cell line was exposed to a non-cytotoxic copper overload to evaluate mitochondrial dynamics, function and cell fate. This induced higher rates of mitochondrial turnover given by an increase in mitochondrial fusion and fission events and in the autophagic flux. The appearance of smaller and condensed mitochondria was also observed. Bioenergetics activity included more respiratory complexes, higher oxygen consumption rate, superoxide production and ATP synthesis, with no decrease in membrane potential. Increased cell proliferation and inhibited differentiation also occurred. Non-cytotoxic copper levels can modify mitochondrial metabolism and cell fate, which could be used in cancer biology and regenerative medicine. © 2016 Elsevier B.V. and Mitochondria Research Society.


PubMed | French Institute of Health and Medical Research and Millennium Institute of Immunology and Immunotherapy
Type: Journal Article | Journal: Immunology letters | Year: 2014

Human Respiratory Syncytial Virus (hRSV) is the leading cause of lower respiratory tract diseases, affecting particularly newborns and young children. This virus is able to modulate the immune response, generating a pro-inflammatory environment in the airways that causes obstruction and pulmonary alterations in the infected host. To date, no vaccines are available for human use and the first vaccine that reached clinical trials produced an enhanced hRSV-associated pathology 50 years ago, resulting in the death of two children. Currently, only two therapeutic approaches have been used to treat hRSV infection in high risk children: 1. Palivizumab, a humanized antibody against the F glycoprotein that reduces to half the number of hospitalized cases and 2. Ribavirin, which fails to have a significant therapeutic effect. A major caveat for these approaches is their high economical cost, which highlights the need of new and affordable therapeutic or prophylactic tools to treat or prevents hRSV infection. Accordingly, several efforts are in progress to understand the hRSV-associated pathology and to characterize the immune response elicited by this virus. Currently, preclinical and clinical trials are being conducted to evaluate safety and efficacy of several drugs and vaccines, which have shown promising results. In this article, we discuss the most important advances in the development of drugs and vaccines, which could eventually lead to better strategies to treat or prevent the detrimental inflammation triggered by hRSV infection.

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