title: E74-like factor 3 and nuclear factor-κB regulate lipocalin-2 expression in chondrocytes.
abstract: E74-like factor 3 (ELF3) is a transcription factor regulated by inflammation in different physio-pathological situations. Lipocalin-2 (LCN2) emerged as a relevant adipokine involved in the regulation of inflammation. In this study we showed for the first time the involvement of ELF3 in the control of LCN2 expression and its cooperation with nuclear factor-κB (NFκB). Our results will help to better understand of the role of ELF3, NFκB and LCN2 in the pathophysiology of articular cartilage.
  
  
  
  E74-like factor 3 (ELF3) is a transcription factor induced by inflammatory cytokines in chondrocytes that increases gene expression of catabolic and inflammatory mediators. Lipocalin 2 (LCN2) is a novel adipokine that negatively impacts articular cartilage, triggering catabolic and inflammatory responses in chondrocytes. Here, we investigated the control of LCN2 gene expression by ELF3 in the context of interleukin 1 (IL-1)-driven inflammatory responses in chondrocytes. The interaction of ELF3 and nuclear factor-κB (NFκB) in modulating LCN2 levels was also explored. LCN2 mRNA and protein levels, as well those of several other ELF3 target genes, were determined by RT-qPCR and Western blotting. Human primary chondrocytes, primary chondrocytes from wild-type and Elf3 knockout mice, and immortalized human T/C-28a2 and murine ATDC5 cell lines were used in in vitro assays. The activities of various gene reporter constructs were evaluated by luciferase assays. Gene overexpression and knockdown were performed using specific expression vectors and siRNA technology, respectively. ELF3 overexpression transactivated the LCN2 promoter and increased the IL-1-induced mRNA and protein levels of LCN2, as well as the mRNA expression of other pro-inflammatory mediators, in human and mouse chondrocytes. We also identified a collaborative loop between ELF3 and NFκB that amplifies the induction of LCN2. Our findings show a novel role for ELF3 and NFκB in the induction of the pro-inflammatory adipokine LCN2, providing additional evidence of the interaction between ELF3 and NFκB in modulating inflammatory responses, and a better understanding of the mechanisms of action of ELF3 in chondrocytes.
authors.affiliation: SERGAS (Servizo Galego de Saude) and IDIS (Instituto de Investigación Sanitaria de Santiago), Research Laboratory 9, The NEIRID Lab (Neuroendocrine Interactions in Rheumatology and Inflammatory Diseases), Santiago University Clinical Hospital, Santiago de Compostela, 15706, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Conde
authors.affiliation: Tissue Engineering Regeneration and Repair Program, The Hospital for Special Surgery, and Department of Cell and Developmental Biology, Weill Cornell Medical College, New York, NY, USA.
authors.forename: Miguel
authors.initials: M
authors.lastname: Otero
authors.affiliation: SERGAS (Servizo Galego de Saude) and IDIS (Instituto de Investigación Sanitaria de Santiago), Research Laboratory 9, The NEIRID Lab (Neuroendocrine Interactions in Rheumatology and Inflammatory Diseases), Santiago University Clinical Hospital, Santiago de Compostela, 15706, Spain.
authors.forename: Morena
authors.initials: M
authors.lastname: Scotece
authors.affiliation: SERGAS (Servizo Galego de Saude) and IDIS (Instituto de Investigación Sanitaria de Santiago), Research Laboratory 9, The NEIRID Lab (Neuroendocrine Interactions in Rheumatology and Inflammatory Diseases), Santiago University Clinical Hospital, Santiago de Compostela, 15706, Spain.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Abella
authors.affiliation: SERGAS (Servizo Galego de Saude) and IDIS (Instituto de Investigación Sanitaria de Santiago), Research Laboratory 9, The NEIRID Lab (Neuroendocrine Interactions in Rheumatology and Inflammatory Diseases), Santiago University Clinical Hospital, Santiago de Compostela, 15706, Spain.
authors.forename: Verónica
authors.initials: V
authors.lastname: López
authors.affiliation: SERGAS (Servizo Gallego de Saude), Santiago University Clinical Hospital, Division of Orthopaedic Surgery, Santiago de Compostela, Spain.
authors.forename: Jesús
authors.initials: J
authors.lastname: Pino
authors.affiliation: SERGAS (Servizo Galego de Saude) and IDIS (Instituto de Investigación Sanitaria de Santiago), Research Laboratory 9, The NEIRID Lab (Neuroendocrine Interactions in Rheumatology and Inflammatory Diseases), Santiago University Clinical Hospital, Santiago de Compostela, 15706, Spain.
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Gómez
authors.affiliation: SERGAS (Servizo Galego de Saude) and IDIS (Instituto de Investigación Sanitaria de Santiago), Research Laboratory 9, The NEIRID Lab (Neuroendocrine Interactions in Rheumatology and Inflammatory Diseases), Santiago University Clinical Hospital, Santiago de Compostela, 15706, Spain.
authors.forename: Francisca
authors.initials: F
authors.lastname: Lago
authors.affiliation: Tissue Engineering Regeneration and Repair Program, The Hospital for Special Surgery, and Department of Cell and Developmental Biology, Weill Cornell Medical College, New York, NY, USA.
authors.forename: Mary B
authors.initials: MB
authors.lastname: Goldring
authors.affiliation: SERGAS (Servizo Galego de Saude) and IDIS (Instituto de Investigación Sanitaria de Santiago), Research Laboratory 9, The NEIRID Lab (Neuroendocrine Interactions in Rheumatology and Inflammatory Diseases), Santiago University Clinical Hospital, Santiago de Compostela, 15706, Spain. oreste.gualillo@sergas.es.
authors.forename: Oreste
authors.initials: O
authors.lastname: Gualillo
mesh_terms: D000818:Animals; D002460:Cell Line; D019902:Chondrocytes / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D006801:Humans; D007375:Interleukin-1 / Q000235:genetics / Q000378:metabolism; D000071068:Lipocalin-2 / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; C494436:Elf3 protein, mouse; D007375:Interleukin-1; D000071068:Lipocalin-2; D016328:NF-kappa B; D012333:RNA, Messenger; D014157:Transcription Factors; C071332:Lcn2 protein, mouse