title: Progranulin does not bind tumor necrosis factor (TNF) receptors and is not a direct regulator of TNF-dependent signaling or bioactivity in immune or neuronal cells.
abstract: Progranulin (PGRN) is a secreted glycoprotein expressed in neurons and glia that is implicated in neuronal survival on the basis that mutations in the GRN gene causing haploinsufficiency result in a familial form of frontotemporal dementia (FTD). Recently, a direct interaction between PGRN and tumor necrosis factor receptors (TNFR I/II) was reported and proposed to be a mechanism by which PGRN exerts anti-inflammatory activity, raising the possibility that aberrant PGRN-TNFR interactions underlie the molecular basis for neuroinflammation in frontotemporal lobar degeneration pathogenesis. Here, we report that we find no evidence for a direct physical or functional interaction between PGRN and TNFRs. Using coimmunoprecipitation and surface plasmon resonance (SPR) we replicated the interaction between PGRN and sortilin and that between TNF and TNFRI/II, but not the interaction between PGRN and TNFRs. Recombinant PGRN or transfection of a cDNA encoding PGRN did not antagonize TNF-dependent NFκB, Akt, and Erk1/2 pathway activation; inflammatory gene expression; or secretion of inflammatory factors in BV2 microglia and bone marrow-derived macrophages (BMDMs). Moreover, PGRN did not antagonize TNF-induced cytotoxicity on dopaminergic neuroblastoma cells. Last, co-addition or pre-incubation with various N- or C-terminal-tagged recombinant PGRNs did not alter lipopolysaccharide-induced inflammatory gene expression or cytokine secretion in any cell type examined, including BMDMs from Grn+/- or Grn-/- mice. Therefore, the neuroinflammatory phenotype associated with PGRN deficiency in the CNS is not a direct consequence of the loss of TNF antagonism by PGRN, but may be a secondary response by glia to disrupted interactions between PGRN and Sortilin and/or other binding partners yet to be identified.
authors.affiliation: Department of Physiology and Department of Pharmacology, Emory University, School of Medicine, Atlanta, Georgia 30322, USA.
authors.forename: Xi
authors.initials: X
authors.lastname: Chen
authors.forename: Jianjun
authors.initials: J
authors.lastname: Chang
authors.forename: Qiudong
authors.initials: Q
authors.lastname: Deng
authors.forename: Jie
authors.initials: J
authors.lastname: Xu
authors.forename: Thi A
authors.initials: TA
authors.lastname: Nguyen
authors.forename: Lauren H
authors.initials: LH
authors.lastname: Martens
authors.forename: Basar
authors.initials: B
authors.lastname: Cenik
authors.forename: Georgia
authors.initials: G
authors.lastname: Taylor
authors.forename: Kathryn F
authors.initials: KF
authors.lastname: Hudson
authors.forename: Jaegwon
authors.initials: J
authors.lastname: Chung
authors.forename: Kimberley
authors.initials: K
authors.lastname: Yu
authors.forename: Phillip
authors.initials: P
authors.lastname: Yu
authors.forename: Joachim
authors.initials: J
authors.lastname: Herz
authors.forename: Robert V
authors.initials: RV
authors.lastname: Farese
authors.forename: Thomas
authors.initials: T
authors.lastname: Kukar
authors.forename: Malú G
authors.initials: MG
authors.lastname: Tansey
mesh_terms: D033942:Adaptor Proteins, Vesicular Transport / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D017077:Culture Media, Conditioned / Q000494:pharmacology; D016207:Cytokines / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics / Q000276:immunology*; D000077155:Granulins; D006801:Humans; D047468:Immunoprecipitation; D036341:Intercellular Signaling Peptides and Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D007546:Isoquinolines / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000276:immunology; D008264:Macrophages / Q000187:drug effects / Q000276:immunology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D017628:Microglia / Q000187:drug effects / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D000077153:Progranulins; D011485:Protein Binding / Q000235:genetics; D018124:Receptors, Tumor Necrosis Factor / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D020349:Surface Plasmon Resonance; D014162:Transfection; D000099183:Sortilin
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; D017077:Culture Media, Conditioned; D016207:Cytokines; D000077155:Granulins; D036341:Intercellular Signaling Peptides and Proteins; D007546:Isoquinolines; D008070:Lipopolysaccharides; D016328:NF-kappa B; D000077153:Progranulins; D018124:Receptors, Tumor Necrosis Factor; D011994:Recombinant Proteins; D000099183:Sortilin; C120204:Grn protein, mouse; C017475:lucifer yellow