title: A previously unrecognized protein-protein interaction between TWEAK and CD163: potential biological implications.
abstract: TWEAK (TNF-like weak inducer of apoptosis) is a TNF superfamily member implicated in several mechanisms. Although fibroblast growth factor inducible 14 (Fn14)/TweakR has been reported as its receptor, an as yet unrecognized surface molecule(s) might modulate TWEAK function(s). Thus, we set out to identify TWEAK-binding proteins by screening a combinatorial peptide library. Cyclic peptides containing a consensus motif (WXDDG) bound to TWEAK specifically. These peptides were similar to CD163, a scavenger receptor cysteine-rich domain family member, restricted to the monocyte/macrophage lineage and responsible for the uptake of circulating haptoglobin-hemoglobin (Hp-Hb) complexes. Sequence profile analysis suggested that TWEAK mimicked the CD163 natural ligand (Hp-Hb). Consistently, we show dose-dependent TWEAK binding to CD163 and blockade by an anti-CD163 Ab. In a competition assay, both soluble CD163 and Fn14/TweakR were able to compete off TWEAK binding to coated Fn14/TweakR or CD163, respectively. Flow-cytometry and immunofluorescence assays showed that human monocytes (Fn14/TweakR negative and CD163 positive) bind TWEAK, thus blocking the recognition of CD163 and reducing the activation mediated by a specific mAb in these cells. We demonstrate that monocytes can sequester TWEAK from supernatants, thus preventing tumor cell apoptosis; this effect was reverted by preincubation with the peptide mimicking CD163 or with a mAb anti-CD163, indicating specificity. Finally, we show that recombinant human TWEAK binding to CD163-transfected Chinese hamster ovary cells is inhibited by the presence of either unlabeled TWEAK or the Hp-Hb complex. Together, these data are consistent with the hypothesis that CD163 either acts as a TWEAK scavenger in pathological conditions or serves as an alternate receptor for TWEAK in cells lacking Fn14/TweakR.
authors.affiliation: Department of Genitourinary Medical Oncology, The University of Texas M.D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
authors.forename: Laura C
authors.initials: LC
authors.lastname: Bover
authors.forename: Marina
authors.initials: M
authors.lastname: Cardó-Vila
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kuniyasu
authors.forename: Jessica
authors.initials: J
authors.lastname: Sun
authors.forename: Roberto
authors.initials: R
authors.lastname: Rangel
authors.forename: Motohiro
authors.initials: M
authors.lastname: Takeya
authors.forename: Bharat B
authors.initials: BB
authors.lastname: Aggarwal
authors.forename: Wadih
authors.initials: W
authors.lastname: Arap
authors.forename: Renata
authors.initials: R
authors.lastname: Pasqualini
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D015703:Antigens, CD / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015214:Antigens, Differentiation, Myelomonocytic / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D000074049:Cytokine TWEAK; D006801:Humans; D007457:Iodine Radioisotopes / Q000032:analysis; D008024:Ligands; D008969:Molecular Sequence Data; D009000:Monocytes / Q000187:drug effects; D019151:Peptide Library; D010455:Peptides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D025941:Protein Interaction Mapping; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018124:Receptors, Tumor Necrosis Factor / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D000074050:TWEAK Receptor; D048069:Tumor Necrosis Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000098902:CD163 Antigen
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D000098902:CD163 Antigen; D000074049:Cytokine TWEAK; D007457:Iodine Radioisotopes; D008024:Ligands; D019151:Peptide Library; D010455:Peptides; D011956:Receptors, Cell Surface; D018124:Receptors, Tumor Necrosis Factor; D011994:Recombinant Proteins; C000613297:TNFRSF12A protein, human; C109743:TNFSF12 protein, human; D000074050:TWEAK Receptor; D048069:Tumor Necrosis Factors