Lee, James J.

ABSTRACT A MyoD family gene was identified in the ascidian Ciona intestinalis and designated CiMDF (Ciona intestinalisMuscle Determination Factor). Expression of CiMDF was restricted to the muscle cells of the developing embryo and the body-wall muscle of adults. Northern blots showed that two differentially regulated CiMDF transcripts were expressed during development. A 1.8 kb transcript (CiMDFa) appeared first and was gradually replaced by a 2.7 kb transcript (CiMDFb). These transcripts encoded essentially identical MyoD family proteins with the exception of a 68 amino acid C-terminal sequence present in CiMDFb that was absent from CiMDFa. Although both CiMDFa and CiMDFb contained the cysteine-rich/basichelix loop helix domain (Cys-rich/bHLH) present in all MyoD family proteins, only CiMDFb contained the region near the C terminus (Domain III) characteristic of this gene family. Genomic Southern blots showed that C. intestinalis has only one MyoD family gene, suggesting that CiMDFa and CiMDFb result from differential processing of primary transcripts. The existence of two MyoD family proteins that are differentially expressed during ascidian embryogenesis has novel parallels to vertebrate muscle development and may reflect conserved myogenic regulatory mechanisms among chordates.

OBJECTIVES: Eosinophilic esophagitis (EoE), a chronic food allergic disease, lacks sensitive and specific peripheral biomarkers. We hypothesized that levels of EoE-related biomarkers captured using a 1-hour minimally invasive Esophageal String Test (EST) would correlate with mucosal eosinophil counts and tissue concentrations of these same biomarkers. We aimed to determine whether a 1-hour EST accurately distinguishes active from inactive EoE or a normal esophagus. METHODS: In a prospective, multisite study, children and adults (ages 7–55 years) undergoing a clinically indicated esophagogastroduodenoscopy performed an EST with an esophageal dwell time of 1 hour. Subjects were divided into 3 groups: active EoE, inactive EoE, and normal esophageal mucosa. Eosinophil-associated protein levels were compared between EST effluents and esophageal biopsy extracts. Statistical modeling was performed to select biomarkers that best correlated with and predicted eosinophilic inflammation. RESULTS: One hundred thirty-four subjects (74 children, 60 adults) with active EoE (n = 62), inactive EoE (n = 37), and patient controls with a normal esophagus (n = 35) completed the study. EST-captured eosinophil-associated biomarkers correlated significantly with peak eosinophils/high-power field, endoscopic visual scoring, and the same proteins extracted from mucosal biopsies. Statistical modeling, using combined eotaxin-3 and major basic protein-1 concentrations, led to the development of EoE scores that distinguished subjects with active EoE from inactive EoE or normal esophagi. Eighty-seven percent of children, 95% of parents, and 92% of adults preferred the EST over endoscopy if it provided similar information. DISCUSSION: The 1-hour EST accurately distinguishes active from inactive EoE in children and adults and may facilitate monitoring of disease activity in a safe and minimally invasive fashion.

Abstract The mouse eosinophil peroxidase (mEPO) gene was cloned by screening a random-primed bone marrow cDNA library at reduced criteria using a hEPO cDNA. An mEPO cDNA was subsequently used to isolate the mEPO gene from a λ-genomic library. The mEPO gene displays a high degree of conservation with its human homologue: the transcription units are approximately the same size, conserve the relative size and position of the 12 exons associated with each gene, and at a nucleotide level the mouse and human EPO genes are 86% identical in the protein coding regions and 66% identical in the 3'-untranslated trailer regions. This strong conservation extends to the encoded proteins which show ~90% amino acid identity. Expression of the mEPO gene is restricted to tissues containing eosinophil progenitor cells (e.g., bone marrow and spleen), a pattern similar to the expression of another murine eosinophil granule protein, major basic protein.

Abstract We have identified a new eosinophil major basic protein gene family member in the mouse and have given it the designation murine major basic protein-2 (mMBP-2). The gene was initially characterized as a unique expressed sequence tag (EST) clone having significant identity to the previously recognized member of this gene family, mMBP-1. The EST was used to screen and isolate mMBP-2 from a bone marrow cDNA library. In addition, a genomic clone of mMBP-2 was isolated and this gene was shown to be physically linked to within 100 kb of mMBP-1 on the central region of mouse chromosome 2. Progressive similarity alignment of the deduced mMBP-2 open reading frame demonstrates the apparent conservation of the “pre-pro-mature” protein structure found in the other known mammalian MBPs. Mature mMBP-2 maintains the cationic nature associated with these proteins with a predicted pI of 9.95. However, unlike the human MBPs, which display a three orders of magnitude charge difference [hMBP-1 (pI11.4) vs. hMBP-2 (pI8.7)], mMBP-2 is only slightly less cationic than mMBP-1 (pI 10.5). Expression studies demonstrate that transcription of the mMBP-2 gene parallels mMBP-1 and is confined to hematopoietic compartments engaged in eosinophilopoiesis. Moreover, using mMBP-1 knockout mice and immunohistochemistry with an antisera that recognizes both mMBP-1 and -2, we demonstrate that mMBP-2 protein expression is restricted to eosinophil lineage-committed cells. J. Leukoc. Biol. 67: 567–576; 2000.

Abstract Adenosine signaling has been implicated in chronic lung diseases such as asthma and chronic obstructive pulmonary disease; however, the specific roles of the various adenosine receptors in processes central to these disorders are not well understood. In this study, we have investigated the role(s) of the A3 adenosine receptor in adenosine-dependent pulmonary inflammation observed in adenosine deaminase (ADA)-deficient mice. The A3 receptor (A3R) was found to be expressed in eosinophils and mucus-producing cells in the airways of ADA-deficient mice. Treatment of ADA-deficient mice with MRS 1523, a selective A3R antagonist, prevented airway eosinophilia and mucus production. Similar findings were seen in the lungs of ADA/A3 double knockout mice. Although eosinophils were decreased in the airways of ADA-deficient mice following antagonism or removal of the A3R, elevations in circulating and lung interstitial eosinophils persisted, suggesting signaling through the A3R is needed for the migration of eosinophils into the airways. These findings identify an important role for the A3R in regulating lung eosinophilia and mucus production in an environment of elevated adenosine.

Abstract Extracellular cyclophilins have been well described as chemotactic factors for various leukocyte subsets. This chemotactic capacity is dependent upon interaction of cyclophilins with the cell surface signaling receptor CD147. Elevated levels of extracellular cyclophilins have been documented in several inflammatory diseases. We propose that extracellular cyclophilins, via interaction with CD147, may contribute to the recruitment of leukocytes from the periphery into tissues during inflammatory responses. In this study, we examined whether extracellular cyclophilin-CD147 interactions might influence leukocyte recruitment in the inflammatory disease allergic asthma. Using a mouse model of asthmatic inflammation, we show that 1) extracellular cyclophilins are elevated in the airways of asthmatic mice; 2) mouse eosinophils and CD4+ T cells express CD147, which is up-regulated on CD4+ T cells upon activation; 3) cyclophilins induce CD147-dependent chemotaxis of activated CD4+ T cells in vitro; 4) in vivo treatment with anti-CD147 mAb significantly reduces (by up to 50%) the accumulation of eosinophils and effector/memory CD4+ T lymphocytes, as well as Ag-specific Th2 cytokine secretion, in lung tissues; and 5) anti-CD147 treatment significantly reduces airway epithelial mucin production and bronchial hyperreactivity to methacholine challenge. These findings provide a novel mechanism whereby asthmatic lung inflammation may be reduced by targeting cyclophilin-CD147 interactions.

Key PointsThe loss of the two most abundant eosinophil granule proteins disrupts the production of blood eosinophils from marrow progenitors. Knockout animals deficient for both MBP-1 and EPX represent a novel strain of mice with a specific and congenital loss of eosinophils.

ABSTRACT Eosinophils are generally linked to innate host defense against helminths, as well as the pathologies associated with allergic diseases, such as asthma. Nonetheless, the activities of eosinophils remain poorly understood, which in turn, has prevented detailed definitions of their role(s) in health and disease. Homologous recombination in embryonic stem cells was used to insert a mammalianized Cre recombinase in the ORF encoding Epx. This knock-in strategy overcame previous inefficiencies associated with eosinophil-specific transgenic approaches and led to the development of a knock-in strain of mice (eoCRE), capable of mediating recombination of “floxed” reporter cassettes in >95% of peripheral blood eosinophils. We also showed that this Cre expression was limited exclusively to eosinophil-lineage committed cells with no evidence of Cre-mediated toxicity. The efficiency and specificity of Cre expression in eoCRE mice were demonstrated further in a cross with a knock-in mouse containing a “(flox-stop-flox)” DTA cassette at the ROSA26 locus, generating yet another novel, eosinophil-less strain of mice. The development of eoCRE mice represents a milestone in studies of eosinophil biology, permitting eosinophil-specific gene targeting and overexpression in the mouse as part of next-generation studies attempting to define eosinophil effector functions.

BackgroundStudies comparing the ability of staining methods to detect eosinophils in formalin‐fixed canine skin are lacking.Hypothesis/ObjectivesThe aim of this study was to compare the effectiveness of eosinophil peroxidase monoclonal antibody (EPXmAb), Luna and haematoxylin and eosin (H&E) to detect eosinophils in fixed canine skin by assessing the following parameters: (i) specificity of eosinophil staining; (ii) extracellular eosinophil granule staining; (iii) tissue background staining; (iv) contrast between eosinophil and surrounding tissue staining; and (v) differences in the number of eosinophils detected by each stain.MethodsThree serial sections of formalin‐fixed, paraffin‐embedded tissues of predominantly eosinophilic skin diseases (n = 8), noneosinophilic skin diseases (n = 7) and normal canine skin (n = 1) were stained with the three stains. Each parameter was independently assessed and scored by two investigators.ResultsLuna and EPXmAb were specific in detecting eosinophils. The EPXmAb was significantly more effective than Luna (P < 0.001) and H&E (P < 0.001) in its ability to detect extracellular eosinophil granules (i.e. to detect intact and released eosinophil granules). The EPXmAb showed significantly less background staining compared with Luna (P = 0.0005). Moreover, significantly more stain contrast was noted with EPXmAb compared with Luna (P = 0.003) and H&E (P < 0.001). There was no significant difference between the mean eosinophil counts among the three stains.Conclusion and clinical importanceThe three stains were shown to be useful to detect and quantify eosinophils in fixed canine skin. The EPXmAb‐based immunohistochemical stain proved to be a novel tool to detect eosinophils in canine skin.

ABSTRACTObjective:Differentiation between the common etiologies of dense esophageal eosinophilia such as gastroesophageal reflux disease (GERD) and eosinophilic esophagitis can be difficult. We hypothesized that histologic features may provide diagnostic clues concerning the etiology of esophageal eosinophilia.Methods:We performed a retrospective chart review of 204 children with the diagnosis of esophagitis characterized by ≥15 eosinophils (eos) per high‐power field (HPF) in at least 1 biopsy. We then restricted our analysis to subjects who had received at least 8 weeks of only proton pump inhibitors (PPIs) followed by endoscopy and who had a clinicopathologic response to this treatment. Symptoms, endoscopic findings, and pathologic descriptions were reviewed and an eosinophil peroxidase (EPX) index was determined to assess for degranulation/eosinophil activation.Results:Of the 204 identified charts, 7 subjects identified met the inclusion criteria. Five of these 7 patients showed a clinicopathologic response to PPIs after their follow‐up endoscopy, (mean peak eosinophil count: 92 vs 5 eos/HPF, and EPX index: 39.2 vs 14.6, pre‐ and posttreatment, respectively). Two patients experienced initial resolution of symptoms and esophageal eosinophilia with PPI therapy; however, within 17–23 months they redeveloped symptoms and esophageal eosinophilia while receiving PPI therapy at the time of a third endoscopy (mean peak eosinophil count: 40 vs 11 vs 36 eos/HPF, and EPX index: 44 vs 21 vs 36.5, pre‐, post‐ and posttreatment, respectively). No clinicopathologic features or degranulation patterns differentiated subjects with GERD/PPI responsive esophageal eosinophilia from those who had transient response to PPI treatment.Conclusions:No clinicopathologic features differentiated subjects who responded to PPI treatment. PPI treatment can be helpful to exclude GERD and PPI responsive esophageal eosinophilia but long‐term follow‐up is critical in the management of esophagitis.