title: Human articular chondrocytes with higher aldehyde dehydrogenase activity have stronger expression of COL2A1 and SOX9.
abstract: OBJECTIVE
  To determine in human articular chondrocytes the activity of Aldehyde dehydrogenase (ALDH), which are reported as stem/progenitor cell marker in various adult tissues and evaluate gene expression of ALDH1A isoforms.
  
  
  METHODS
  ALDH activity was evaluated by flow cytometry with Aldefluor™ assay in cells, isolated from human osteoarthritic (OA) cartilage. Its coexpression with surface markers was identified. Cells were sorted according to ALDH activity, and gene expression in sorted populations (ALDH(+) and ALDH(-)) was analyzed by RTq-PCR with Taqman(®) assay.
  
  
  RESULTS
  About 40% of freshly isolated chondrocytes demonstrated ALDH activity that remarkably declined during monolayer culture. Markers CD54 and CD55 were significantly stronger expressed, while CD47, CD140b, CD146 and CD166 were depleted in ALDH-expressing (ALDH(pos)) cells. Gene expression analysis revealed significantly higher expression of chondrocyte-specific genes COL2A1, SOX9 and SERPINA1 and lower expression of osteogenic markers RUNX2 and osteocalcin (BGLAP) in sorted ALDH(+) fraction. COL1A1, ACAN, ALPL and stem cell markers NANOG, OCT4, SOX2 and ABCG2 did not differ remarkably between the populations. Genes of isoenzymes ALDH1A2, ALDH1A3 and ALDH2 were strongly expressed, while ALDH1A1 was weakly expressed in chondrocytes. Only ALDH1A2 and ALDH1A3 were significantly enriched in ALDH(+) fraction.
  
  
  CONCLUSIONS
  We identified ALDH activity with significantly stronger expression of CD54 and CD55 in human articular chondrocytes. Gene expression of isotypes ALDH1A2, ALDH1A3 and ALDH2 was identified. Coexpression of ALDH activity with chondrogenic markers suggests its association with collagen II producing chondrocyte phenotype. Isotypes ALDH1A2 and ALDH1A3 can be associated with the ALDH activity in these cells.
authors.affiliation: Department of Regenerative Medicine, State Research Institute Center of Innovative Medicine, Vilnius, Lithuania. Electronic address: ausra.unguryte@ekmi.vu.lt.
authors.forename: A
authors.initials: A
authors.lastname: Unguryte
authors.affiliation: Department of Regenerative Medicine, State Research Institute Center of Innovative Medicine, Vilnius, Lithuania. Electronic address: eiva.bernotiene@ekmi.vu.lt.
authors.forename: E
authors.initials: E
authors.lastname: Bernotiene
authors.affiliation: Department of Regenerative Medicine, State Research Institute Center of Innovative Medicine, Vilnius, Lithuania. Electronic address: edvardas.bagdonas@gmail.com.
authors.forename: E
authors.initials: E
authors.lastname: Bagdonas
authors.affiliation: Department of Regenerative Medicine, State Research Institute Center of Innovative Medicine, Vilnius, Lithuania. Electronic address: sima.garberyte@gmail.com.
authors.forename: S
authors.initials: S
authors.lastname: Garberyte
authors.affiliation: Vilnius University, Medicine Faculty, Vilnius, Lithuania. Electronic address: narunas.porvaneckas@gmail.com.
authors.forename: N
authors.initials: N
authors.lastname: Porvaneckas
authors.affiliation: INSERM U1183, IRMB Hôpital Saint-Eloi, Université Montpellier 1, Montpellier, France; CHU Hôpital Lapeyronie, Montpellier, France. Electronic address: christian.jorgensen@inserm.fr.
authors.forename: C
authors.initials: C
authors.lastname: Jorgensen
mesh_terms: D000368:Aged; D000444:Aldehyde Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D002358:Cartilage, Articular / Q000378:metabolism* / Q000473:pathology; D002469:Cell Separation / Q000379:methods; D002478:Cells, Cultured; D019902:Chondrocytes / Q000378:metabolism*; D024043:Collagen Type II / Q000378:metabolism*; D003114:Colony-Forming Units Assay; D005260:Female; D015870:Gene Expression; D006801:Humans; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000378:metabolism* / Q000473:pathology; D055758:SOX9 Transcription Factor / Q000378:metabolism*
chemical_list: D015415:Biomarkers; C499177:COL2A1 protein, human; D024043:Collagen Type II; D055758:SOX9 Transcription Factor; C527932:SOX9 protein, human; D000444:Aldehyde Dehydrogenase
keywords: Aldehyde dehydrogenase (ALDH); Cartilage; Chondrocyte markers; Chondrocytes; Progenitors