Valledor, Annabel

Nuclear receptors are a superfamily of transcription factors that regulate development and physiology. Our main interest nowadays is to study the biological roles of the Liver X receptor (LXR), a member of the nuclear receptor superfamily that is activated by specific oxydized forms of cholesterol (oxysterols) and metabolites of the cholesterol biosynthetic pathway. Two isoforms of LXR have been identified, LXR-alpha and LXR-beta. LXRs are key regulators of lipid and glucose homeostasis and also play an important role in the regulation of immune and inflammatory responses. We are interested in further exploring the roles of LXRs in the immune response and in the development of diseases with an inflammatory origin.

Models available:

  • Infection by Salmonella typhimurium(mouse)
  • House dust mite-induced allergic asthma (mouse)
  • IFN-g-mediated neuroinflammation (mouse)
  • In vivo peritoneal macrophage proliferation (mouse)

Cells available:

  • Primary bone marrow-derived macrophages
  • Primary bone marrow-derived dendritic cells
  • Peritoneal macrophages (resident and thyoglicollate or concanavalin-elicited)
  • Primary microglia
  • Tumor-associated macrophages
  • In vitro-generated Foam cells

Technology available:

  • Flow cytometry
  • Determination of gene expression by Real time-PCR Determination of NO and ROS production
  • ELISA assays
  • Phagocytosis of apoptotic cells, bacteria and latex beads
  • Bacterial infection (uptake and intracellular replication)
  • Western-blot
  • Chromatin immunoprecipitation assays (ChIP)
  • Other functional tests (Apoptosis, cell cycle, proliferation)

Key publications related to Mye-EUNITER:

  1. Pascual-García M, Rué L, León T, Julve J, Carbó JM, Matalonga J, Auer H, Celada A, Escolà-Gil JC, Steffensen KR, Pérez-Navarro E, Valledor AF. (2013) Reciprocal negative cross-talk between liver X receptors (LXRs) and STAT1: effects on IFN-γ-induced inflammatory responses and LXR-dependent gene expression. J Immunol. 190:6520-32. IF= 5.52.

  2. Pascual-García M, Carbó JM, León T, Matalonga J, Out R, Van Berkel T, Sarrias MR, Lozano F, Celada A, Valledor AF. (2011) Liver X receptors inhibit macrophage proliferation through downregulation of cyclins D1 and B1 and cyclin-dependent kinases 2 and 4. J Immunol. 186:4656-67. IF: 5.78.

  3. Amézaga N, Sanjurjo L, Julve J, Aran G, Pérez-Cabezas B, Bastos-Amador P, Armengol C, Vilella R, Escolà-Gil JC, Blanco-Vaca F, Borràs FE, Valledor AF, Sarrias MR. (2014) Human scavenger protein AIM increases foam cell formation and CD36-mediated oxLDL uptake. J Leukoc Biol. 95:509-20. IF=4.56.

  4. Valledor AF, Comalada M, Santamaría-Babi LF, Lloberas J, Celada A. (2010). Macrophage proinflammatory activation and deactivation: a question of balance. Adv Immunol. 108:1-20.

  5. Pascual-García M, Valledor AF. (2012) Biological roles of liver X receptors in immune cells. Arch Immunol Ther Exp (Warsz) 60:235-49.

Researcher Spotlight:


Annabel Valledor graduated in Biology (1993), conducted Master studies in Immunology (1995-1996) and carried out her PhD in the field of Macrophage Biology at the University of Barcelona, Spain (1994-1998). She then moved to the University of California San Diego (USA) for post-doctoral training (1999-2003), where she worked on the field of transcriptional control by Nuclear Receptors. After a short stay as a visiting scientist at the Karolinska Institutet (Sweden) in 2004, she went back to her home country as a Ramón y Cajal researcher at the Institute of Research in Biomedicine Barcelona. In 2007 she was appointed Associate Professor of Immunology (Serra-Hunter Program) at the University of Barcelona.

Her current interest is focused on the modulation of the immune response by the nuclear receptors LXRs. LXRs become activated by oxysterols and intermediate molecules from the cholesterol biosynthetic pathway and exert bridging roles between lipid homeostasis and the control of inflammation. Current lines of research in her group aim to understand the role of LXRs in diseases of inflammatory origin and in the immune response to pathogens, with special emphasis on the underlying mechanisms.

Annabel is the Vice-Chair of Mye-EUNITER and participates in several WGs within the Action.