Sebastian Castillo Galan

@universidad de los andes

Postdoctoral researcher / Centro de Investigación e Innovación Biomédica. Universidad de Los Andes
Posdoctoral research



              

https://researchid.co/sebastiancastillo

RESEARCH, TEACHING, or OTHER INTERESTS

Molecular Medicine, Physiology, Biochemistry, Genetics and Molecular Biology, Cell Biology

12

Scopus Publications

Scopus Publications



  • Cinaciguat (BAY-582667) Modifies Cardiopulmonary and Systemic Circulation in Chronically Hypoxic and Pulmonary Hypertensive Neonatal Lambs in the Alto Andino
    Felipe A. Beñaldo, Claudio Araya-Quijada, Germán Ebensperger, Emilio A. Herrera, Roberto V. Reyes, Fernando A. Moraga, Alexander Riquelme, Alejandro Gónzalez-Candia, Sebastián Castillo-Galán, Guillermo J. Valenzuela,et al.
    Frontiers Media SA
    Neonatal pulmonary hypertension (NPHT) is produced by sustained pulmonary vasoconstriction and increased vascular remodeling. Soluble guanylyl cyclase (sGC) participates in signaling pathways that induce vascular vasodilation and reduce vascular remodeling. However, when sGC is oxidized and/or loses its heme group, it does not respond to nitric oxide (NO), losing its vasodilating effects. sGC protein expression and function is reduced in hypertensive neonatal lambs. Currently, NPHT is treated with NO inhalation therapy; however, new treatments are needed for improved outcomes. We used Cinaciguat (BAY-582667), which activates oxidized and/or without heme group sGC in pulmonary hypertensive lambs studied at 3,600 m. Our study included 6 Cinaciguat-treated (35 ug kg−1 day−1x 7 days) and 6 Control neonates. We measured acute and chronic basal cardiovascular variables in pulmonary and systemic circulation, cardiovascular variables during a superimposed episode of acute hypoxia, remodeling of pulmonary arteries and changes in the right ventricle weight, vasoactive functions in small pulmonary arteries, and expression of NO-sGC-cGMP signaling pathway proteins involved in vasodilation. We observed a decrease in pulmonary arterial pressure and vascular resistance during the acute treatment. In contrast, the pulmonary pressure did not change in the chronic study due to increased cardiac output, resulting in lower pulmonary vascular resistance in the last 2 days of chronic study. The latter may have had a role in decreasing right ventricular hypertrophy, although the direct effect of Cinaciguat on the heart should also be considered. During acute hypoxia, the pulmonary vascular resistance remained low compared to the Control lambs. We observed a higher lung artery density, accompanied by reduced smooth muscle and adventitia layers in the pulmonary arteries. Additionally, vasodilator function was increased, and vasoconstrictor function was decreased, with modifications in the expression of proteins linked to pulmonary vasodilation, consistent with low pulmonary vascular resistance. In summary, Cinaciguat, an activator of sGC, induces cardiopulmonary modifications in chronically hypoxic and pulmonary hypertensive newborn lambs. Therefore, Cinaciguat is a potential therapeutic tool for reducing pulmonary vascular remodeling and/or right ventricular hypertrophy in pulmonary arterial hypertension syndrome.

  • Contribution of STIM-Activated TRPC-ORAI Channels in Pulmonary Hypertension Induced by Chronic Sustained and Intermittent Hypoxia
    Sebastián Castillo-Galán, Germán A. Arenas, and Rodrigo Iturriaga
    Bentham Science Publishers Ltd.
    Abstract: Sustained and intermittent hypoxia produce vasoconstriction, arterial remodeling, and hypertension in the lung. Stromal interaction molecule (STIM)-activated transient receptor potential channels (TRPC) and calcium release-activated calcium channel protein (ORAI) channels (STOC) play key roles in the progression of pulmonary hypertension in pre-clinical models of animals subjected to sustained and intermittent hypoxia. The available evidence supports the theory that oxidative stress and hypoxic inducible factors upregulate and activate STIM-activated TRPC-ORAI Ca2+ channels, contributing to the pulmonary remodeling and hypertension induced by sustained hypoxia. However, less is known about the effects of oxidative stress and hypoxic inducible factors on the modulation of STIM-activated TRPC-ORAI channels following chronic intermittent hypoxia. In this review, we examined the emerging evidence supporting the theory that oxidative stress and hypoxic inducible factors induced by intermittent hypoxia upregulate and activate STIM-activated TRPC-ORAI Ca2+ channels. In addition, we used bioinformatics tools to search public databases for the genes involved in the upregulation of STIMactivated TRPC-ORAI Ca2+ channels and compare the differential gene expression and biological processes induced by intermittent and sustained hypoxia in lung cells.

  • Crucial Role of Stromal Interaction Molecule-Activated TRPC-ORAI Channels in Vascular Remodeling and Pulmonary Hypertension Induced by Intermittent Hypoxia
    Sebastián Castillo-Galán, Bárbara Riquelme, and Rodrigo Iturriaga
    Frontiers Media SA
    Obstructive sleep apnea (OSA), a sleep breathing disorder featured by chronic intermittent hypoxia (CIH), is associate with pulmonary hypertension. Rats exposed to CIH develop lung vascular remodeling and pulmonary hypertension, which paralleled the upregulation of stromal interaction molecule (STIM)-activated TRPC-ORAI Ca2+ channels (STOC) in the lung, suggesting that STOC participate in the pulmonary vascular alterations. Accordingly, to evaluate the role played by STOC in pulmonary hypertension we studied whether the STOC blocker 2-aminoethoxydiphenyl borate (2-APB) may prevent the vascular remodeling and the pulmonary hypertension induced by CIH in a rat model of OSA. We assessed the effects of 2-APB on right ventricular systolic pressure (RVSP), pulmonary vascular remodeling, α-actin and proliferation marker Ki-67 levels in pulmonary arterial smooth muscle cells (PASMC), mRNA levels of STOC subunits, and systemic and pulmonary oxidative stress (TBARS) in male Sprague-Dawley (200 g) rats exposed to CIH (5% O2, 12 times/h for 8h) for 28 days. At 14 days of CIH, osmotic pumps containing 2-APB (10 mg/kg/day) or its vehicle were implanted and rats were kept for 2 more weeks in CIH. Exposure to CIH for 28 days raised RVSP > 35 mm Hg, increased the medial layer thickness and the levels of α-actin and Ki-67 in PASMC, and increased the gene expression of TRPC1, TRPC4, TRPC6 and ORAI1 subunits. Treatment with 2-APB prevented the raise in RVSP and the increment of the medial layer thickness, as well as the increased levels of α-actin and Ki-67 in PASMC, and the increased gene expression of STOC subunits. In addition, 2-APB did not reduced the lung and systemic oxidative stress, suggesting that the effects of 2-APB on vascular remodeling and pulmonary hypertension are independent on the reduction of the oxidative stress. Thus, our results supported that STIM-activated TRPC-ORAI Ca2+ channels contributes to the lung vascular remodeling and pulmonary hypertension induced by CIH.

  • The Action of 2-Aminoethyldiphenyl Borinate on the Pulmonary Arterial Hypertension and Remodeling of High-Altitude Hypoxemic Lambs
    Sebastián Castillo-Galán, Daniela Parrau, Ismael Hernández, Sebastián Quezada, Marcela Díaz, Germán Ebensperger, Emilio A. Herrera, Fernando A. Moraga, Rodrigo Iturriaga, Aníbal J. Llanos,et al.
    Frontiers Media SA
    Calcium signaling is key for the contraction, differentiation, and proliferation of pulmonary arterial smooth muscle cells. Furthermore, calcium influx through store-operated channels (SOCs) is particularly important in the vasoconstrictor response to hypoxia. Previously, we found a decrease in pulmonary hypertension and remodeling in normoxic newborn lambs partially gestated under chronic hypoxia, when treated with 2-aminoethyldiphenyl borinate (2-APB), a non-specific SOC blocker. However, the effects of 2-APB are unknown in neonates completely gestated, born, and raised under environmental hypoxia. Accordingly, we studied the effects of 2-APB-treatment on the cardiopulmonary variables in lambs under chronic hypobaric hypoxia. Experiments were done in nine newborn lambs gestated, born, and raised in high altitude (3,600 m): five animals were treated with 2-APB [intravenous (i.v.) 10 mg kg–1] for 10 days, while other four animals received vehicle. During the treatment, cardiopulmonary variables were measured daily, and these were also evaluated during an acute episode of superimposed hypoxia, 1 day after the end of the treatment. Furthermore, pulmonary vascular remodeling was assessed by histological analysis 2 days after the end of the treatment. Basal cardiac output and mean systemic arterial pressure (SAP) and resistance from 2-APB- and vehicle-treated lambs did not differ along with the treatment. Mean pulmonary arterial pressure (mPAP) decreased after the first day of 2-APB treatment and remained lower than the vehicle-treated group until the third day, and during the fifth, sixth, and ninth day of treatment. The net mPAP increase in response to acute hypoxia did not change, but the pressure area under the curve (AUC) during hypoxia was slightly lower in 2-APB-treated lambs than in vehicle-treated lambs. Moreover, the 2-APB treatment decreased the pulmonary arterial wall thickness and the α-actin immunoreactivity and increased the luminal area with no changes in the vascular density. Our findings show that 2-APB treatment partially reduced the contractile hypoxic response and reverted the pulmonary vascular remodeling, but this is not enough to normalize the pulmonary hemodynamics in chronically hypoxic newborn lambs.

  • Stim-activated TRPC-ORAI channels in pulmonary hypertension induced by chronic intermittent hypoxia
    Sebastian Castillo‐Galán, German A. Arenas, Roberto V. Reyes, Bernardo J. Krause, and Rodrigo Iturriaga
    Wiley
    Obstructive sleep apnea (OSA), a breathing disorder featured by chronic intermittent hypoxia (CIH) is associated with pulmonary hypertension (PH). Rodents exposed to CIH develop pulmonary vascular remodeling and PH, but the pathogenic mechanisms are not well known. Overexpression of Stim‐activated Transient Receptor Potential Channels (TRPC) and Calcium Release‐Activated Calcium Channel Protein (ORAI) TRPC‐ORAI Ca2+ channels (STOC) has been involved in pulmonary vascular remodeling and PH in sustained hypoxia. However, it is not known if CIH may change STOC levels. Accordingly, we studied the effects of CIH on the expression of STOC subunits in the lung and if these changes paralleled the progression of the vascular pulmonary remodeling and PH in a preclinical model of OSA. Male Sprague‐Dawley rats (∼200 g) were exposed to CIH (5%O2, 12 times/h for 8 h) for 14, 21, and 28 days. We measured right ventricular systolic pressure (RVSP), cardiac morphometry with MRI, pulmonary vascular remodeling, and wire‐myographic arterial responses to KCl and endothelin‐1 (ET‐1). Pulmonary RNA and protein STOC levels of TRPC1, TRPC4, TRPC6, ORAI 1, ORAI 2, and STIM1 subunits were measured by qPCR and western blot, and results were compared with age‐matched controls. CIH elicited a progressive increase of RVSP and vascular contractile responses to KCl and ET‐1, leading to vascular remodeling and augmented right ventricular ejection fraction, which was significant at 28 days of CIH. The levels of TRPC1, TRPC4, TRPC 6, ORAI 1, and STIM 1 channels increased following CIH, and some of them paralleled morphologic and functional changes. Our findings show that CIH increased pulmonary STOC expression, paralleling vascular remodeling and PH.


  • Premature vascular aging in guinea pigs affected by fetal growth restriction
    Adolfo A. Paz, German A. Arenas, Sebastián Castillo-Galán, Estefanía Peñaloza, Gabriela Cáceres-Rojas, José Suazo, Emilio A. Herrera, and Bernardo J. Krause
    MDPI AG
    Cardiovascular risk associated with fetal growth restriction (FGR) could result from an early impaired vascular function. However, whether this effect results in premature vascular aging has not been addressed. We studied the ex vivo reactivity of carotid and femoral arteries in fetal (near term), adults (eight months-old) and aged (16 months-old) guinea pigs in normal (control) and FGR offspring. Additionally, an epigenetic marker of vascular aging (i.e., LINE-1 DNA methylation) was evaluated in human umbilical artery endothelial cells (HUAEC) from control and FGR subjects. Control guinea pig arteries showed an increased contractile response (KCl-induced) and a progressive impairment of NO-mediated relaxing responses as animals get older. FGR was associated with an initial preserved carotid artery reactivity as well as a later significant impairment in NO-mediated responses. Femoral arteries from FGR fetuses showed an increased contractility but a decreased relaxing response compared with control fetuses, and both responses were impaired in FGR-adults. Finally, FGR-HUAEC showed decreased LINE-1 DNA methylation compared with control-HUAEC. These data suggest that the aging of vascular function occurs by changes in NO-mediated responses, with limited alterations in contractile capacity. Further, these effects are accelerated and imposed at early stages of development in subjects exposed to a suboptimal intrauterine environment.

  • Revisiting the role of TRP, orai, and ASIC channels in the pulmonary arterial response to hypoxia
    Roberto V. Reyes, Sebastián Castillo-Galán, Ismael Hernandez, Emilio A. Herrera, Germán Ebensperger, and Aníbal J. Llanos
    Frontiers Media SA
    The pulmonary arteries are exquisitely responsive to oxygen changes. They rapidly and proportionally contract as arterial PO2 decrease, and they relax as arterial PO2 is re-established. The hypoxic pulmonary vasoconstriction (HPV) is intrinsic since it does not require neural or endocrine factors, as evidenced in isolated vessels. On the other hand, pulmonary arteries also respond to sustained hypoxia with structural and functional remodeling, involving growth of smooth muscle medial layer and later recruitment of adventitial fibroblasts, secreted mitogens from endothelium and changes in the response to vasoconstrictor and vasodilator stimuli. Hypoxic pulmonary arterial vasoconstriction and remodeling are relevant biological responses both under physiological and pathological conditions, to explain matching between ventilation and perfusion, fetal to neonatal transition of pulmonary circulation and pulmonary artery over-constriction and thickening in pulmonary hypertension. Store operated channels (SOC) and receptor operated channels (ROC) are plasma membrane cationic channels that mediate calcium influx in response to depletion of internal calcium stores or receptor activation, respectively. They are involved in both HPV and pathological remodeling since their pharmacological blockade or genetic suppression of several of the Stim, Orai, TRP, or ASIC proteins in SOC or ROC complexes attenuate the calcium increase, the tension development, the pulmonary artery smooth muscle proliferation, and pulmonary arterial hypertension. In this Mini Review, we discussed the evidence obtained in in vivo animal models, at the level of isolated organ or cells of pulmonary arteries, and we identified and discussed the questions for future research needed to validate these signaling complexes as targets against pulmonary hypertension.

  • Deciphering the function of the blunt circadian rhythm of melatonin in the newborn lamb: Impact on adrenal and heart
    Maria Seron-Ferre, Claudia Torres-Farfan, Francisco J Valenzuela, Sebastian Castillo-Galan, Auristela Rojas, Natalia Mendez, Henry Reynolds, Guillermo J Valenzuela, and Anibal J Llanos
    The Endocrine Society
    &NA; Neonatal lambs, as with human and other neonates, have low arrhythmic endogenous levels of melatonin for several weeks until they start their own pineal rhythm of melatonin production at approximately 2 weeks of life. During pregnancy, daily rhythmic transfer of maternal melatonin to the fetus has important physiological roles in sheep, nonhuman primates, and rats. This melatonin rhythm provides a circadian signal and also participates in adjusting the physiology of several organs in preparation for extrauterine life. We propose that the ensuing absence of a melatonin rhythm plays a role in neonatal adaptation. To test this hypothesis, we studied the effects of imposing a high‐amplitude melatonin rhythm in the newborn lamb on (1) clock time‐related changes in cortisol and plasma variables and (2) clock time‐related changes of gene expression of clock genes and selected functional genes in the adrenal gland and heart. We treated newborn lambs with a daily oral dose of melatonin (0.25 mg/kg) from birth to 5 days of age, recreating a high‐amplitude melatonin rhythm. This treatment suppressed clock time‐related changes of plasma adrenocorticotropic hormone, cortisol, clock gene expression, and functional genes in the newborn adrenal gland. In the heart, it decreased heart/body weight ratio, increased expression of Anp and Bnp, and resulted in different heart gene expression from control newborns. The interference of this postnatal melatonin treatment with the normal postnatal pattern of adrenocortical function and heart development support a physiological role for the window of flat postnatal melatonin levels during the neonatal transition.

  • 2-Aminoethyldiphenylborinate modifies the pulmonary circulation in pulmonary hypertensive newborn lambs partially gestated at high altitude
    S. Castillo-Galán, S. Quezada, F. Moraga, G. Ebensperger, E. A. Herrera, F. Beñaldo, I. Hernández, R. Ebensperger, S. Ramírez, A. J. Llanos,et al.
    American Physiological Society
    Calcium signaling through store-operated channels (SOC) is involved in hypoxic pulmonary hypertension. We determined whether a treatment with 2-aminoethyldiphenylborinate (2-APB), a compound with SOC blocker activity, reduces pulmonary hypertension and vascular remodeling. Twelve newborn lambs exposed to perinatal chronic hypoxia were studied, six of them received a 2-APB treatment and the other six received vehicle treatment for 10 days in both cases. Throughout this period, we recorded cardiopulmonary variables and on day 11 we evaluated the response to an acute hypoxic challenge. Additionally, we assessed the vasoconstrictor and vasodilator function in isolated pulmonary arteries as well as their remodeling in lung slices. 2-APB reduced pulmonary arterial pressure between the 3rd and 10th days, cardiac output between the 4th and 8th days, and pulmonary vascular resistance at the 10th day of treatment. The pulmonary vasoconstrictor response to acute hypoxia was reduced by the end of treatment. 2-APB also decreased maximal vasoconstrictor response to the thromboxane mimetic U46619 and endothelin-1 and increased maximal relaxation to 8-bromoguanosine 3′,5′-cyclic monophosphate (8-BrcGMP). The maximal relaxation and potency to phosphodiesterase-5 and Rho-kinase inhibition with sildenafil and fasudil, respectively, were also increased. Finally, 2-APB reduced the medial and adventitial layers' thickness, the expression of α-actin, and the percentage of Ki67-positive nuclei of small pulmonary arteries. Taken together, our results indicate that 2-APB reduces pulmonary hypertension, vasoconstrictor responses, and pathological remodeling in pulmonary hypertensive lambs. We conclude that SOC targeting may be a useful strategy for the treatment of neonatal pulmonary hypertension; however, further testing of specific blockers is needed.