title: Early Transcriptomic Response to LDL and oxLDL in Human Vascular Smooth Muscle Cells.
abstract: BACKGROUND
  Although nowadays it is well known that the human transcriptome can importantly vary according to external or environmental condition, the reflection of this concept when studying oxidative stress and its direct relationship with gene expression profiling during the process of atherogenesis has not been thoroughly achieved.
  
  
  OBJECTIVE
  The ability to analyze genome-wide gene expression through transcriptomics has shown that the genome responds dynamically to diverse stimuli. Here, we describe the transcriptome of human vascular smooth muscle cells (hVSMC) stimulated by native and oxidized low-density lipoprotein (nLDL and oxLDL respectively), with the aim of assessing the early molecular changes that induce a response in this cell type resulting in a transcriptomic transformation. This expression has been demonstrated in atherosclerotic plaques in vivo and in vitro, particularly in the light of the oxidative modification hypothesis of atherosclerosis.
  
  
  RESULTS
  Total RNA was isolated with TRIzol reagent (Life Technologies) and quality estimated using an Agilent 2100 bioanalyzer. The transcriptome of hVSMC under different experimental conditions (1,5 and 24 hours for nLDL and oxLDL) was obtained using the GeneChip Human Gene 1.0 ST (Affymetrix) designed to measure gene expression of 28,869 well-annotated genes. A fixed fold-change cut-off corresponding to ± 2 was used to identify genes exhibiting the most significant variation and statistical significance (P< 0.05), and 8 genes validated by qPCR using Taqman probes.
  
  
  CONCLUSIONS
  10 molecular processes were significantly affected in hVSMC: Apoptosis and cell cycle, extracellular matrix remodeling, DNA repair, cholesterol efflux, cGMP biosynthesis, endocytic mechanisms, calcium homeostasis, redox balance, membrane trafficking and finally, the immune response to inflammation. The evidence we present supporting the hypothesis for the involvement of oxidative modification of several processes and metabolic pathways in atherosclerosis is strengthen by the fact that gene expression patterns obtained when hVSMC are incubated for a long period of time in the presence of nLDL, correspond very much the same as when cells are incubated for a short period of time in the presence of chemically modified oxLDL. Our results indicate that under physiological conditions and directly related to specific environmental conditions, LDL particles most probably suffer chemical modifications that initially serve as an alert signal to overcome a harmful stimulus that with time might get transformed to a pathological pattern and therefore consolidate a pathological condition.
authors.affiliation: Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México City, México.
authors.forename: Salvador
authors.initials: S
authors.lastname: Damián-Zamacona
authors.affiliation: Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México City, México.
authors.forename: Paola
authors.initials: P
authors.lastname: Toledo-Ibelles
authors.affiliation: Instituto Nacional de Medicina Genómica, México City, México.
authors.forename: Mabel Z
authors.initials: MZ
authors.lastname: Ibarra-Abundis
authors.affiliation: Instituto Nacional de Medicina Genómica, México City, México.
authors.forename: Laura
authors.initials: L
authors.lastname: Uribe-Figueroa
authors.affiliation: Instituto Nacional de Medicina Genómica, México City, México.
authors.forename: Enrique
authors.initials: E
authors.lastname: Hernández-Lemus
authors.affiliation: Instituto Nacional de Medicina Genómica, México City, México.
authors.forename: Karla Paola
authors.initials: KP
authors.lastname: Macedo-Alcibia
authors.affiliation: Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México City, México.
authors.forename: Blanca
authors.initials: B
authors.lastname: Delgado-Coello
authors.affiliation: Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México City, México.
authors.forename: Jaime
authors.initials: J
authors.lastname: Mas-Oliva
authors.affiliation: Instituto Nacional de Medicina Genómica, México City, México.
authors.forename: Juan Pablo
authors.initials: JP
authors.lastname: Reyes-Grajeda
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000378:metabolism; D002478:Cells, Cultured; D002784:Cholesterol / Q000378:metabolism; D016000:Cluster Analysis; D004260:DNA Repair / Q000187:drug effects; D004705:Endocytosis / Q000187:drug effects; D005260:Female; D006801:Humans; D008077:Lipoproteins, LDL / Q000494:pharmacology*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D012313:RNA / Q000302:isolation & purification / Q000378:metabolism; D013997:Time Factors; D059467:Transcriptome / Q000187:drug effects*
chemical_list: D018797:Cell Cycle Proteins; D008077:Lipoproteins, LDL; C099252:oxidized low density lipoprotein; D012313:RNA; D002784:Cholesterol; D002118:Calcium