RESUMO
Thioredoxin domain containing 5 (TXNDC5) is a protein disulfide isomerase involved in several diseases related to oxidative stress, energy metabolism and cellular inflammation. In a previous manuscript, a negative association between fatty liver development and hepatic Txndc5 expression was observed. To study the role of TXNDC5 in the liver, we generated Txndc5-deficient mice. The absence of the protein caused an increased metabolic need to gain weight along with a bigger and fatter liver. RNAseq was performed to elucidate the putative mechanisms, showing a substantial liver overexpression of serum amyloid genes (Saa1, Saa2) with no changes in hepatic protein, but discrete plasma augmentation by the gene inactivation. Higher levels of malonyldialdehyde, apolipoprotein A1 and platelet activating factor-aryl esterase activity were also found in serum from Txndc5-deficient mice. However, no difference in the distribution of high-density lipoproteins (HDL)-mayor components and SAA was found between groups, and even the reactive oxygen species decreased in HDL coming from Txndc5-deficient mice. These results confirm the relation of this gene with hepatic steatosis and with a fasting metabolic derive remedying an acute phase response. Likewise, they pose a new role in modulating the nature of HDL particles, and SAA-containing HDL particles are not particularly oxidized.
RESUMO
Introducción: Estudios previos sugieren que la pérdida de función de NOR-1 modula la activación de las células musculares lisas vasculares (CMLV). En este estudio utilizamos un ratón que sobreexpresa NOR-1 en CMLV para analizar su efecto en la activación celular y en la hiperplasia de la íntima inducida por estrés hemodinámico. Métodos Para generar el modelo animal el ADNc de NOR-1 humano se situó bajo el control del promotor de SM22α. La expresión de NOR-1 se analizó mediante PCR a tiempo real, Western-blot, inmunohistoquímica e inmunocitoquímica, y su funcionalidad se determinó mediante ensayos de actividad luciferasa. Como índice de proliferación celular se determinó la incorporación de timidina tritiada. La carótida izquierda se sometió a ligadura y en secciones de la misma se realizaron análisis morfométricos e inmunohistoquímicos. Resultados El transgénico desarrollado exhibía niveles significativos de NOR-1 humano en la aorta y las arterias carótidas. En las CMLV de los animales transgénicos se detectó un aumento de la actividad transcripcional de la ciclina D2, una mayor actividad proliferativa y niveles incrementados de Myh10. En estos animales la ligadura de la carótida indujo mayor formación de neoíntima y de estenosis que en los animales control, en consonancia con el marcaje de Myh10 e histona H3 fosforilada. Conclusiones Estos resultados refuerzan el papel de NOR-1 en la proliferación de las CMLV y en el remodelado vascular, y permiten proponer este modelo como una herramienta útil para estudiar la implicación de este receptor en la función vascular y en enfermedades como la arteriosclerosis y la reestenosis
Introduction: Previous studies have shown that the loss of NOR-1 function modulates the activation of vascular smooth muscle cells (VSMC). In this study we use a mouse that over-expresses human NOR-1 in VSMC to analyze the effect of a gain of NOR-1 function on the activation ofVSMC and in the hyperplasia of the intima induced by hemodynamic stress. Methods: To generate the transgenic animal the human NOR-1 cDNA was placed under the control of the SM22promoter. The expression of NOR-1 was analyzed by real time PCR, Westernblot, immunohistochemistry and immunocitochemistry, and NOR-1 functionality was evaluated by luciferase activity assays. The incorporation of tritiated thymidine was determined as a cellproliferation index. The left carotid artery was ligated, and cross-sections were subjected tomorphometric and immunostaining analysis. Results: The transgenic mouse exhibited significant levels of human NOR-1 in aorta and carotidarteries. In aortic VSMC from transgenic mice an increase in the transcriptional activity of ciclinD2 was detected, as well as higher proliferative rates and increased levels of the marker Myh10.In these animals, carotid artery ligation induced a greater neointimal formation and a higherstenotic grade than in wild-type animals, in accordance with the labelling detected for Myh10and phosphorylated Histone H3.Conclusions: These results reinforce the role of NOR-1 in VSMC proliferation and in vascular remodelling, and allow us to propose this model as a useful tool to study the involvement ofNOR-1 in vascular function and in vascular diseases such as atherosclerosis and restenosis
