title: Biochemical characterization of endogenously formed eosinophilic crystals in the lungs of mice.
abstract: Crystals seldom form spontaneously within tissues of mammals, except in the urinary tract or in association with eosinophil-rich diseases in humans (Charcot-Leyden crystals). Endogenously formed eosinophilic crystals have been reported in respiratory tract and other tissues of several strains of mice, but the biochemical characterization of these crystals has not been reported. In this study, eosinophilic crystal formation was examined in homozygous C57BL/6J viable motheaten mice, lung-specific surfactant apoprotein C promoter/soluble human tumor necrosis factor p75 receptor type II fusion protein transgenic mice (C57BL/6NTac x Sv/129), and CD40L-deficient mice with spontaneous Pneumocystis carinii infection. In viable motheaten but not wild type mice, rapidly developing crystals represented a major feature of the fatal lung injury induced by macrophage dysregulation. Conversely, eosinophilic crystals did not form until 4-8 months of age in transgenic and CD40L-deficient mice and were present in 10-30% of age-matched wild type controls. Mass spectrometry analysis of proteins from bronchoalveolar lavage fluid identified the crystals as Ym1, sometimes referred to as T-lymphocyte-derived eosinophil chemotactic factor. The Ym1 sequence was homologous to chitinase, and enzymatic assays indicated a 3-5-fold increase in chitinase activity compared with control mice. Intracellular and extracellular crystals associated with epithelial damage suggested that the crystals may contribute to lung inflammation through mechanical damage and enzymatic degradation.
authors.affiliation: Immunex Corporation, Seattle, Washington 98101, USA.
authors.forename: L
authors.initials: L
authors.lastname: Guo
authors.forename: R S
authors.initials: RS
authors.lastname: Johnson
authors.forename: J C
authors.initials: JC
authors.lastname: Schuh
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD / Q000235:genetics; D001059:Apoproteins / Q000235:genetics; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D023201:CD40 Ligand; D019744:Chemokines, C; D002631:Chemotactic Factors, Eosinophil / Q000302:isolation & purification*; D002688:Chitinases / Q000032:analysis; D003460:Crystallization; D004804:Eosinophils / Q000737:chemistry* / Q000473:pathology; D006023:Glycoproteins / Q000302:isolation & purification*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008168:Lung / Q000737:chemistry* / Q000473:pathology; D008222:Lymphokines / Q000302:isolation & purification*; D008245:Lysophospholipase; D013058:Mass Spectrometry; D008562:Membrane Glycoproteins / Q000235:genetics; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000235:genetics*; D011510:Proteolipids / Q000235:genetics; D011663:Pulmonary Surfactants / Q000235:genetics; D018124:Receptors, Tumor Necrosis Factor / Q000235:genetics; D047889:Receptors, Tumor Necrosis Factor, Type II; D020539:Sequence Analysis, Protein; D012795:Sialoglycoproteins / Q000302:isolation & purification*
chemical_list: D015703:Antigens, CD; D001059:Apoproteins; D019744:Chemokines, C; D002631:Chemotactic Factors, Eosinophil; D006023:Glycoproteins; D047908:Intracellular Signaling Peptides and Proteins; D008222:Lymphokines; D008562:Membrane Glycoproteins; D010446:Peptide Fragments; D011510:Proteolipids; D011663:Pulmonary Surfactants; D018124:Receptors, Tumor Necrosis Factor; D047889:Receptors, Tumor Necrosis Factor, Type II; D012795:Sialoglycoproteins; C092390:XCL1 protein, human; C486249:Xcl1 protein, mouse; C018997:lymphotactin; D023201:CD40 Ligand; D008245:Lysophospholipase; C011711:lysolecithin acylhydrolase; C509249:PTPN6 protein, human; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; C509248:Ptpn6 protein, mouse; D002688:Chitinases