title: Lymphocyte gene expression signatures from patients and mouse models of hereditary hemochromatosis reveal a function of HFE as a negative regulator of CD8+ T-lymphocyte activation and differentiation in vivo.
abstract: Abnormally low CD8+ T-lymphocyte numbers is characteristic of some patients with hereditary hemochromatosis (HH), a MHC-linked disorder of iron overload. Both environmental and genetic components are known to influence CD8+ T-lymphocyte homeostasis but the role of the HH associated protein HFE is still insufficiently understood. Genome-wide expression profiling was performed in peripheral blood CD8+ T lymphocytes from HH patients selected according to CD8+ T-lymphocyte numbers and from Hfe-/- mice maintained either under normal or high iron diet conditions. In addition, T-lymphocyte apoptosis and cell cycle progression were analyzed by flow cytometry in HH patients. HH patients with low CD8+ T-lymphocyte numbers show a differential expression of genes related to lymphocyte differentiation and maturation namely CCR7, LEF1, ACTN1, NAA50, P2RY8 and FOSL2, whose expression correlates with the relative proportions of naïve, central and effector memory subsets. In addition, expression levels of LEF1 and P2RY8 in memory cells as well as the proportions of CD8+ T cells in G2/M cell cycle phase are significantly different in HH patients compared to controls. Hfe-/- mice do not show alterations in CD8+ T-lymphocyte numbers but differential gene response patterns. We found an increased expression of S100a8 and S100a9 that is most pronounced in high iron diet conditions. Similarly, CD8+ T lymphocytes from HH patients display higher S100a9 expression both at the mRNA and protein level. Altogether, our results support a role for HFE as a negative regulator of CD8+ T-lymphocyte activation. While the activation markers S100a8 and S100a9 are strongly increased in CD8+ T cells from both, Hfe-/- mice and HH patients, a differential profile of genes related to differentiation/maturation of CD8+ T memory cells is evident in HH patients only. This supports the notion that HFE contributes, at least in part, to the generation of low peripheral blood CD8+ T lymphocytes in HH.
authors.affiliation: I3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal; Basic and Clinical Research on Iron Biology, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal; Doctoral Program in Biomedicine, Faculdade de Medicina, Universidade do Porto, Porto, Portugal.
authors.forename: Mónica
authors.initials: M
authors.lastname: Costa
authors.affiliation: I3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal; Basic and Clinical Research on Iron Biology, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal; Clinical Hematology, Santo António Hospital-Centro Hospitalar do Porto, Porto, Portugal.
authors.forename: Eugénia
authors.initials: E
authors.lastname: Cruz
authors.affiliation: I3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal; Basic and Clinical Research on Iron Biology, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.
authors.forename: Susana
authors.initials: S
authors.lastname: Oliveira
authors.affiliation: Genomics Core Facility, European Molecular Biology Laboratory, Heidelberg, Germany.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Benes
authors.affiliation: Genomics Core Facility, European Molecular Biology Laboratory, Heidelberg, Germany.
authors.forename: Tomi
authors.initials: T
authors.lastname: Ivacevic
authors.affiliation: Clinical Hematology, Santo António Hospital-Centro Hospitalar do Porto, Porto, Portugal.
authors.forename: Maria João
authors.initials: MJ
authors.lastname: Silva
authors.affiliation: I3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal; Basic and Clinical Research on Iron Biology, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.
authors.forename: Inês
authors.initials: I
authors.lastname: Vieira
authors.affiliation: Clinical Hematology, Santo António Hospital-Centro Hospitalar do Porto, Porto, Portugal.
authors.forename: Francisco
authors.initials: F
authors.lastname: Dias
authors.affiliation: Clinical Hematology, Santo António Hospital-Centro Hospitalar do Porto, Porto, Portugal.
authors.forename: Sónia
authors.initials: S
authors.lastname: Fonseca
authors.affiliation: Clinical Hematology, Santo António Hospital-Centro Hospitalar do Porto, Porto, Portugal.
authors.forename: Marta
authors.initials: M
authors.lastname: Gonçalves
authors.affiliation: Clinical Hematology, Santo António Hospital-Centro Hospitalar do Porto, Porto, Portugal.
authors.forename: Margarida
authors.initials: M
authors.lastname: Lima
authors.affiliation: Advanced Flow Cytometry Unit, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.
authors.forename: Catarina
authors.initials: C
authors.lastname: Leitão
authors.affiliation: Departments of Pediatric Hematology, Oncology and Immunology, University of Heidelberg and Molecular Medicine Partnership Unit, Heidelberg, Germany.
authors.forename: Martina U
authors.initials: MU
authors.lastname: Muckenthaler
authors.affiliation: I3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal; Basic and Clinical Research on Iron Biology, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.
authors.forename: Jorge
authors.initials: J
authors.lastname: Pinto
authors.affiliation: I3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal; Basic and Clinical Research on Iron Biology, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal; Clinical Hematology, Santo António Hospital-Centro Hospitalar do Porto, Porto, Portugal; Molecular Immunology and Pathology, ICBAS-Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal.
authors.forename: Graça
authors.initials: G
authors.lastname: Porto
mesh_terms: D000818:Animals; D017209:Apoptosis; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism*; D059447:Cell Cycle Checkpoints; D002454:Cell Differentiation; D004195:Disease Models, Animal; D005260:Female; D030342:Genetic Diseases, Inborn / Q000378:metabolism*; D006432:Hemochromatosis / Q000378:metabolism*; D000071020:Hemochromatosis Protein; D015395:Histocompatibility Antigens Class I / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D059467:Transcriptome
chemical_list: C103673:HFE protein, human; D000071020:Hemochromatosis Protein; D015395:Histocompatibility Antigens Class I; D008565:Membrane Proteins