Uteroglobin (UG) suppresses extracellular matrix invasion by normal and cancer cells that express the high affinity UG-binding proteins

Recombinant CC16 protein inhibits the production of pro-inflammatory cytokines via NF-κB and p38 MAPK pathways in LPS-activated RAW264.7 macrophages

Accumulating evidence indicates that Clara cell protein-16 (CC16) has anti-inflammatory functions, although the involved molecular pathways have not been completely elucidated. Here, we evaluated the effect of recombinant rat CC16 (rCC16) on the expression of tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), and IL-8 in lipopolysaccharide (LPS)-stimulated mouse macrophages (RAW264.7 cells) and explored the underlying molecular mechanisms. It was found that rCC16 inhibited LPS-induced TNF-α, IL-6, and IL-8 expression at both the messenger ribonucleicacid (mRNA) level and protein level in a concentration-dependent manner, as demonstrated by real-time reverse transcriptase-polymerase chain reaction and enzyme-linked immunosorbent assay. Such suppressive effects were accompanied by the inhibition of transcriptional activity and the deoxyribonucleic acid binding activity of nuclear factor (NF)-κB but not activator protein (AP)-1. Western blot analysis further revealed that rCC16 inhibited the increase of nuclear NF-κB and the reduction of cytosolic NF-κB, the phosphorylation and reduction of NF-κB inhibitory protein IκBα, and the p38 mitogen-activated protein kinase (MAPK)-dependent NF-κB activation by phosphorylation at Ser276 of its p65 subunit. Furthermore, rCC16 was found to have no effect on the phosphorylation of c-Jun N-terminal kinase, c-Jun, or the nuclear translocation of c-Jun. In addition, reduction of TNF-α, IL-6, and IL-8 were reversed when the level of endogenous uteroglobin-binding protein was reduced by RNA interference in rCC16- and LPS-treated RAW264.7 cells. Our data suggest that rCC16 suppresses LPS-mediated inflammatory mediator TNF-α, IL-6, and IL-8 production by inactivating NF-κB and p38 MAPK but not AP-1 in RAW264.7 cells.

Comprehensive transcriptome profiling of squamous cell carcinoma of horn in Bos indicus

Squamous cell carcinoma (SCC) of horn is frequently observed in Bos indicus affecting 1% of cattle population and accounting 83.34% of total tumours found. The transcriptome profile of horn cancer (HC) tissue and the matched normal (HN) tissue were analysed by RNA-seq using Roche 454 sequencing. A total of 1 504 900 reads comprising of 612 MB data were used to identify differentially expressed genes using CLC Genomic Workbench. These include up-regulation of KRT6A, KRT6B, KRT6C, KRT14, SFN, KRT84, PI3, COL17A1, ANLN, SERPINB5 and down-regulation of BOLA, SCGB1A1, CXCL17, KRT19, BPIFB1, NR4A1 and TFF3 in HC, which are involved in regulation of gene transcription, cell proliferation, apoptosis, cell survival and metabolic pathways. The qPCR analysis of several targets suggested concordance of gene expression profile with RNA-seq analysis. The present findings would provide basis for further screening of genes and identification of markers for early diagnosis and therapeutic intervention of HC.

Antiflammin-1 attenuates bleomycin-induced pulmonary fibrosis in mice

BACKGROUND

Antiflammin-1 (AF-1), a derivative of uteroglobin (UG), is a synthetic nonapeptide with diverse biological functions. In the present study, we investigated whether AF-1 has a protective effect against bleomycin-induced pulmonary fibrosis.

METHODS

C57BL/6 mice were injected with bleomycin intratracheally to create an animal model of bleomycin-induced pulmonary fibrosis. On Day 7 and Day 28, we examined the anti-inflammatory effect and antifibrotic effect, respectively, of AF-1 on the bleomycin-treated mice. The effects of AF-1 on the transforming growth factor-beta 1 (TGF-β1)-induced proliferation of murine lung fibroblasts (NIH3T3) were examined by a bromodeoxycytidine (BrdU) incorporation assay and cell cycle analysis.

RESULTS

Severe lung inflammation and fibrosis were observed in the bleomycin-treated mice on Day 7 and Day 28, respectively. Administration of AF-1 significantly reduced the number of neutrophils in the bronchoalveolar lavage fluid (BALF) and the levels of tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β) in the lung homogenates on Day 7. Histological examination revealed that AF-1 markedly reduced the number of infiltrating cells on Day 7 and attenuated the collagen deposition and destruction of lung architecture on Day 28. The hydroxyproline (HYP) content was significantly decreased in the AF-1-treated mice. In vitro, AF-1 inhibited the TGF-β1-induced proliferation of NIH3T3 cells, which was mediated by the UG receptor.

CONCLUSIONS

AF-1 has anti-inflammatory and antifibrotic actions in bleomycin-induced lung injury. We propose that the antifibrotic effect of AF-1 might be related to its suppression of fibroblast growth in bleomycin-treated lungs and that AF-1 has potential as a new therapeutic tool for pulmonary fibrosis.

Lack of an endogenous anti-inflammatory protein in mice enhances colonization of B16F10 melanoma cells in the lungs

Emerging evidence indicates a link between inflammation and cancer metastasis, but the molecular mechanism(s) remains unclear. Uteroglobin (UG), a potent anti-inflammatory protein, is constitutively expressed in the lungs of virtually all mammals. UG-knock-out (UG-KO) mice, which are susceptible to pulmonary inflammation, and B16F10 melanoma cells, which preferentially metastasize to the lungs, provide the components of a model system to determine how inflammation and metastasis are linked. We report here that B16F10 cells, injected into the tail vein of UG-KO mice, form markedly elevated numbers of tumor colonies in the lungs compared with their wild type littermates. Remarkably, UG-KO mouse lungs overexpress two calcium-binding proteins, S100A8 and S100A9, whereas B16F10 cells express the receptor for advanced glycation end products (RAGE), which is a known receptor for these proteins. Moreover, S100A8 and S100A9 are potent chemoattractants for RAGE-expressing B16F10 cells, and pretreatment of these cells with a blocking antibody to RAGE suppressed migration and invasion. Interestingly, in UG-KO mice S100A8/S100A9 concentrations in blood are lowest in tail vein and highest in the lungs, which most likely guide B16F10 cells to migrate to the lungs. Further, B16F10 cells treated with S100A8 or S100A9 overexpress matrix metalloproteinases, which are known to promote tumor invasion. Most notably, the metastasized B16F10 cells in UG-KO mouse lungs express MMP-2, MMP-9, and MMP-14 as well as furin, a pro-protein convertase that activates MMPs. Taken together, our results suggest that a lack of an anti-inflammatory protein leads to increased pulmonary colonization of melanoma cells and identify RAGE as a potential anti-metastatic drug target.

Uteroglobin: a steroid-inducible immunomodulatory protein that founded the Secretoglobin superfamily

Blastokinin or uteroglobin (UG) is a steroid-inducible, evolutionarily conserved, secreted protein that has been extensively studied from the standpoint of its structure and molecular biology. However, the physiological function(s) of UG still remains elusive. Isolated from the uterus of rabbits during early pregnancy, UG is the founding member of a growing superfamily of proteins called Secretoglobin (Scgb). Numerous studies demonstrated that UG is a multifunctional protein with antiinflammatory/ immunomodulatory properties. It inhibits soluble phospholipase A(2) activity and binds and perhaps sequesters hydrophobic ligands such as progesterone, retinols, polychlorinated biphenyls, phospholipids, and prostaglandins. In addition to its antiinflammatory activities, UG manifests antichemotactic, antiallergic, antitumorigenic, and embryonic growth-stimulatory activities. The tissue-specific expression of the UG gene is regulated by several steroid hormones, although a nonsteroid hormone, prolactin, further augments its expression in the uterus. The mucosal epithelia of virtually all organs that communicate with the external environment express UG, and it is present in the blood, urine, and other body fluids. Although the physiological functions of this protein are still under investigation, a single nucleotide polymorphism in the UG gene appears to be associated with several inflammatory/autoimmune diseases. Investigations with UG-knockout mice revealed that the absence of this protein leads to phenotypes that suggest its critical homeostatic role(s) against oxidative damage, inflammation, autoimmunity, and cancer. Recent studies on UG-binding proteins (receptors) provide further insight into the multifunctional nature of this protein. Based on its antiinflammatory and antiallergic properties, UG is a potential drug target.

Interaction of antiflammin-1 with uteroglobin-binding protein induces phosphorylation of ERK1/2 in NIH 3T3 cells

Previously, it has been suggested that uteroglobin (UG)-binding protein functions as a putative receptor of UG; however, the specific epitope of UG that interacts with this receptor has not yet been identified. The downstream events of UG-binding protein signaling remain unclear. Here we report that antiflammin-1 (AF-1, a bioactive C-terminal peptide of UG) specifically binds to UG-binding protein and has a cellular signaling consequence. We reduced the level of endogenous UG-binding protein expression in murine fibroblast cell line NIH 3T3 by RNA interference and found that knockdown of UG-binding protein inhibited AF-1-induced extracellular signal-regulated kinase 1 and 2 (ERK1/2) phosphorylation. Meanwhile, the interaction between AF-1 and UG-binding protein was confirmed by flow cytometry-based binding assays and co-localization of AF-1 and enhanced green fluorescent protein (EGFP)-tagged UG-binding protein. The present study provides evidence for the first time for AF-1 binding with UG-binding protein, and preliminarily characterized UG-binding protein as a point downstream of AF-1 in mediating ERK phosphorylation.

Mice lacking uteroglobin are highly susceptible to developing pulmonary fibrosis

Uteroglobin (UG) is an anti-inflammatory protein secreted by the airway epithelia of all mammals. UG-knockout (UG-KO) mice sporadically develop focal pulmonary fibrosis (PF), a group of complex interstitial disorders of the lung that has high mortality and morbidity; however, the molecular mechanism(s) remains unclear. We report here that UG-KO mice are extraordinarily sensitive to bleomycin, an anti-cancer agent known to induce PF and readily develop PF when treated with an extremely low dose of bleomycin that has virtually no effect on the wild type littermates. We further demonstrate that UG prevents PF suppressing bleomycin-induced production of pro-inflammatory T-helper 2 cytokines and TGF-beta, which are also pro-fibrotic. Our results define a critical role of UG in preventing the development of PF and provide the proof of principle that recombinant UG may have therapeutic potential.

Interaction of uteroglobin with lipocalin-1 receptor suppresses cancer cell motility and invasion

Cellular migration and invasion are critical for important biological processes including cancer metastasis. We previously reported that uteroglobin (UG), a multifunctional secreted protein, binds to several cell types inhibiting migration and invasion [G.C. Kundu, A.K. Z. Zhang Mandal, G. Mantile-Selvaggi, A.B. Mukherjee (1998) Uteroglobin (UG) suppresses extracellular matrix invasion by normal and cancer cells that express the high affinity UG-binding proteins. J Biol Chem. 273: 22819-22824]. More recently, we reported that HTB-81 adenocarcinoma cells, which do not bind UG, are refractory to UG-mediated inhibition of migration and invasion [Z. Zhang, G.C. Kundu, D. Panda, A.K. Mandal et al. (1999) Loss of transformed phenotype in cancer cells by overexpression of the uteroglobin gene. Proc Natl Acad Sci U S A. 96, 3963-3968]. Since UG shares several biological properties with lipocalin-1 that mediates some of its biological effects via its receptor (Lip-1R), we sought to determine whether UG might interact with Lip-1R and inhibit migration and invasion of HTB-81 cells. To address this question, we first transfected COS-1 cells, which do not bind UG, with a Lip-1R-cDNA construct and performed binding assays using 125I-human UG (hUG). The results show that hUG binds Lip-1R on these cells with high specificity. Further, transfection of HTB-81 cells with the same construct yielded 125I-hUG binding with high affinity (Kd=18 nM) and specificity. The hUG-Lip-1R interaction was further confirmed by transfecting HTB-81, HTB-30 and HTB-174 cells, which are refractory to UG-binding, with a green fluorescent protein (GFP)-Lip-1R-cDNA construct and testing for Lip-1R-hUG colocalization by fluorescence microscopy. Finally, we demonstrate that Lip-1R-hUG interaction on Lip-1R transfected HTB-81 cells renders them fully responsive to hUG-mediated inhibition of migration and invasion. Taken together, these results suggest that Lip-1R is at least one of the UG-binding proteins through which UG exerts anti-motility and anti-invasive effects.

Uteroglobin induces the development and cellular proliferation of the mouse early embryo

Two-cell mouse embryos cultured in vitro in the presence of either purified rabbit uteroglobin (UG) or recombinant human UG developed and proliferated faster than controls cultured in the absence of this protein. Both the percentage of embryos developing to the blastocyst stage and the number of cells per embryo were increased. Treatment with UG for 3 hr was enough to trigger this response. The effect of UG was blocked by genistein, an inhibitor of tyrosine protein kinases, suggesting the involvement of these kinases in the stimulation of the embryo by UG. To further support this suggestion, embryos were metabolically labeled in vitro with [32P] and the phosphorylated proteins were immunoprecipitated with anti-phosphotyrosine. Analysis of the immunoprecipitates by SDS-PAGE showed that UG induced the phosphorylation of several proteins of M(r) between 200 and 37 kDa. This induction was observed after 1 hr of stimulation with UG and further increased after 3 hr of treatment. Since UG is synthesized and secreted in the uterus and the oviduct, these results suggest a physiological role of this protein in the correct development of the embryo in vivo.

HIN-1, an inhibitor of cell growth, invasion, and AKT activation

The HIN-1 gene encoding a small, secreted protein is silenced due to methylation in a substantial fraction of breast, prostate, lung, and pancreatic carcinomas, suggesting a potential tumor suppressor function. The receptor of HIN-1 is unknown, but ligand-binding studies indicate the presence of high-affinity cell surface HIN-1 binding on epithelial cells. Here, we report that HIN-1 is a potent inhibitor of anchorage-dependent and anchorage-independent cell growth, cell migration, and invasion. Expression of HIN-1 in synchronized cells inhibits cell cycle reentry and the phosphorylation of the retinoblastoma protein (Rb), whereas in exponentially growing cells, HIN-1 induces apoptosis without apparent cell cycle arrest and effect on Rb phosphorylation. Investigation of multiple signaling pathways revealed that mitogen-induced phosphorylation and activation of AKT are inhibited in HIN-1-expressing cells. In addition, expression of constitutively activate AKT abrogates HIN-1-mediated growth arrest. Taken together, these studies provide further evidence that HIN-1 possesses tumor suppressor functions, and that these activities may be mediated through the AKT signaling pathway.

Uteroglobin inhibits prostaglandin F2alpha receptor-mediated expression of genes critical for the production of pro-inflammatory lipid mediators

Prematurity is one of the leading causes of infant mortality. It may result from intrauterine infection, which mediates premature labor by stimulating the production of inflammatory lipid mediators such as prostaglandin F2alpha (PGF2alpha). The biological effects of PGF2alpha are mediated via the G protein-coupled receptor FP; however, the molecular mechanism(s) of FP signaling that mediates inflammatory lipid mediator production remains unclear. We reported previously that in the human uterus, a composite organ in which fibroblast, epithelial, and smooth muscle cells are the major constituents, an inverse relationship exists between the levels of PGF2alpha and a steroid-inducible anti-inflammatory protein, uteroglobin. Here we report that, in NIH 3T3 fibroblasts and human uterine smooth muscle cells, FP signaling is mediated via multi-kinase pathways in a cell type-specific manner to activate NF-kappaB, thus stimulating the expression of cyclooxygenase-2. Cyclooxygenase-2 is a critical enzyme for the production of prostaglandins from arachidonic acid, which is released from membrane phospholipids by phospholipase A2, the expression of which is also stimulated by PGF2alpha. Most importantly, uteroglobin inhibits FP-mediated NF-kappaB activation and cyclooxygenase-2 gene expression by binding and most likely by sequestering PGF2alpha into its central hydrophobic cavity, thereby preventing FP-PGF2alpha interaction and suppressing the production of inflammatory lipid mediators. We propose that uteroglobin plays important roles in maintaining homeostasis in organs that are vulnerable to inadvertent stimulation of FP-mediated inflammatory response.

Uteroglobin represses allergen-induced inflammatory response by blocking PGD2 receptor-mediated functions

Uteroglobin (UG) is an antiinflammatory protein secreted by the epithelial lining of all organs communicating with the external environment. We reported previously that UG-knockout mice manifest exaggerated inflammatory response to allergen, characterized by increased eotaxin and Th2 cytokine gene expression, and eosinophil infiltration in the lungs. In this study, we uncovered that the airway epithelia of these mice also express high levels of cyclooxygenase (COX)-2, a key enzyme for the production of proinflammatory lipid mediators, and the bronchoalveolar lavage fluid (BALF) contain elevated levels of prostaglandin D₂. These effects are abrogated by recombinant UG treatment. Although it has been reported that prostaglandin D₂ mediates allergic inflammation via its receptor, DP, neither the molecular mechanism(s) of DP signaling nor the mechanism by which UG suppresses DP-mediated inflammatory response are clearly understood. Here we report that DP signaling is mediated via p38 mitogen–activated protein kinase, p44/42 mitogen–activated protein kinase, and protein kinase C pathways in a cell type–specific manner leading to nuclear factor–κB activation stimulating COX-2 gene expression. Further, we found that recombinant UG blocks DP-mediated nuclear factor–κB activation and suppresses COX-2 gene expression. We propose that UG is an essential component of a novel innate homeostatic mechanism in the mammalian airways to repress allergen-induced inflammatory responses.

IFN-gamma stimulates the expression of a novel secretoglobin that regulates chemotactic cell migration and invasion

IFNs are a family of cytokines that alert the immune system against viral infections of host cells. The IFNs (IFN-alpha, IFN-beta, and IFN-gamma) interact with specific cellular receptors and stimulate the production of second messengers, leading to the expression of antiviral and immunomodulatory proteins. We report in this study that IFN-gamma stimulates the expression of a novel gene that encodes a protein with 30% amino acid sequence identity with uteroglobin, the founding member of the newly formed Secretoglobin (SCGB) superfamily. We named this protein IFN-gamma-inducible SCGB (IIS), because its expression in lymphoblast cells is augmented by IFN-gamma treatment. IIS is expressed in virtually all tissues, and the highest level of expression is detectable in lymph nodes, tonsil, cultured lymphoblasts, and the ovary. Interestingly, although the expression of IIS mRNA is not significantly different in resting lymphoid cells, it is markedly elevated in activated CD8(+) and CD19(+) cells. Furthermore, treatment of lymphoblast cells with IIS antisense phosphorothioate (S)-oligonucleotides prevents chemotactic migration and invasion. Taken together, these results raise the possibility that this novel SCGB has immunological functions.

Increased Susceptibility of Mice Lacking Clara Cell 10-kDa Protein to Lung Tumorigenesis by 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone, a Potent Carcinogen in Cigarette Smoke

Ninety percent of all human lung cancers are related to cigarette smoking. Both tobacco smoke and lung tumorigenesis are associated with drastically reduced levels of Clara cell 10-kDa protein (CC10), a multifunctional secreted protein, naturally produced by the airway epithelia of virtually all mammals. We previously reported that the expression of CC10 is markedly reduced in animals exposed to 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, NNK, a potent carcinogen in tobacco smoke. Furthermore, it has been reported that CC10 expression, induced in certain tumor cells, reverses the transformed phenotype. We demonstrate here that NNK exposure of CC10-knock-out (CC10-KO) mice causes a significantly higher incidence of airway epithelial hyperplasia and lung adenomas compared with wild type (WT) littermates (30% CC10-KO versus 5% WT, p = 0.041). We also found that compared with NNK-treated WT mice, CC10-KO mice manifest increased frequency of K-ras mutation, elevated level of Fas ligand (FasL) expression, and increased MAPK/Erk phosphorylation, all of which are considered predisposing events in NNK-induced lung tumorigenesis. We propose that CC10 has a protective role against NNK-induced lung tumorigenesis mediated via down-regulation of the above-mentioned predisposing events.

Recombinant protein 1/secretoglobin 1A1 participates in the actin polymerization of human platelets

BACKGROUND

Human protein 1 which was originally isolated from pathological urine is identified with clara cell 10 kDa protein and uteroglobin. It has immunomodulatory and anti-inflammatory effects in many vertebrates. Although there have been thorough studies on the structure, molecular biology and biochemical characteristics, the precise mechanism of its biological activities is unknown. The purpose of this research is to clarify the biochemical mechanism of protein 1 through its effect on the platelet aggregation process.

METHODS

Changes in calcium mobilization, actin filament concentrations and functions of integrin alphaIIbbeta3 resulting from platelet stimulation were measured in the presence or absence of recombinant protein 1 (rP1).

RESULTS

Recombinant protein 1 inhibited U46619- and thapsigargin-induced platelet aggregation by preventing store mediated calcium entry (SMCE). The binding of rP1 to resting platelets induced an increase in the actin filament that accompanied the structural changes of alphaIIbbeta3. When rP1-pretreated platelets were activated by thrombin or thapsigargin, the alterations in the actin filament and alphaIIbbeta3 resulting from the stimulation decreased.

CONCLUSION

These results suggest that rP1 inhibits platelet aggregation by participation in the actin polymerization through which SMCE is mediated.

Immunohistochemical analysis of Clara cell secretory protein expression in a transgenic model of mouse lung carcinogenesis

Immunohistochemical methods have been widely used to determine the histogenesis of spontaneous and chemically-induced mouse lung tumors. Typically, antigens for either alveolar Type II cells or bronchiolar epithelial Clara cells are studied. In the present work, the morphological and immunohistochemical phenotype of a transgenic mouse designed to develop lung tumors arising from Clara cells was evaluated. In this model, Clara cell-specific transformation is accomplished by directed expression of the SV40 large T antigen (TAg) under the mouse Clara cell secretory protein (CC10) promoter. In heterozygous mice, early lesions at 1 month of age consisted of hyperplastic bronchiolar epithelial cells. These progressed to adenoma by 2 months as proliferating epithelium extended into adjacent alveolar spaces. By 4 months, a large portion of the lung parenchyma was composed of tumor masses. Expression of constitutive CC10 was diminished in transgenic animals at all time points. Only the occasional cell or segment of the bronchiolar epithelium stained positively for CC10 by immunohistochemistry, and all tumors were found to be uniformly negative for staining. These results were corroborated by Western blotting, where CC10 was readily detectable in whole lung homogenate from nontransgenic animals, but not detected in lung from transgenic animals at any time point. Tumors were also examined for expression of surfactant apoprotein C (SPC), an alveolar Type II cell-specific marker, and found to be uniformly negative for staining. These results indicate that, in this transgenic model, expression of CC10, which is widely used to determine whether lung tumors arise from Clara cells, was reduced and subsequently lost during Clara cell tumor progression.

A novel lacrimal gland autoantigen in the NOD mouse model of Sjögren's syndrome

Recent research has demonstrated a crucial role for autoantibodies in the pathogenesis of Sjögren's syndrome (SS)-like disease in the non-obese diabetic (NOD) mouse, but it remains to be determined which antibody species among all those present are directly related to the various aspects of pathology. To identify autoantigens in the NOD mouse system, we have taken the approach of using immunoglobulin (Ig)G purified from sera of NOD mice exhibiting SS-like symptoms to screen cDNA expression libraries derived from exocrine gland mRNA. Here we report the identification of a novel autoantigen, designated LGP10, expressed in lacrimal and submandibular glands. Autoantibodies to this protein are prominent in the sera of NOD mice starting at 11-12 weeks of age, but not in control nonautoimmune mice. LGP10 has no known function, but bears similarities to various other proteins produced by epithelia. Interestingly, all of these similar proteins have been linked to immunosuppression and/or steroid binding, both processes that could have a significant impact on pathological features of SS.

Characterization and cloning of two isoforms of heteroglobin, a novel heterodimeric glycoprotein of the secretoglobin-uteroglobin family showing tissue-specific and sex differential expression

Heteroglobin (HGB) is a 39-kDa heterodimeric protein detected under non-reducing conditions in harderian, parotid, and submaxillary glands and saliva of the Syrian hamster with antiserum raised against the carboxyl end deduced from the female harderian gland cDNA FHG22 (Dominguez, P. (1995) FEBS Lett. 376, 257-261). After reduction, only one 5.6-kDa polypeptide, named HGB.A, was immunodetected and identified by sequencing as the mature FHG22 product. Tissue-specific expression of HGB.A and HGB mimics that of FHG22 mRNA, with sex differences in submaxillary and harderian glands. Purification of HGB revealed it consists of HGB.A disulfide bonded to HGB.B, a 33.5-kDa N-glycosylated subunit that yields a 9-kDa core polypeptide after deglycosylation. Two highly homologous (96.2%) cDNA clones (HGB.B1 and HGB.B2) encoding 94 amino acid-long isoforms were identified by screening a female harderian gland library with an HGB.B probe. The corresponding mature polypeptides are 78 amino acids long with 12 differences, but 3 putative N-glycosylation sites are maintained. The expression of HGB.B mRNAs is parallel to that of HGB and HGB.A, but no HGB.B2 mRNA was detected in submaxillary glands. Homology studies indicate that HGB.A and HGB.B1/HGB.B2 belong to different subfamilies of the secretoglobin-uteroglobin family and form heterodimers as previously described.

Adenoviral mediated uteroglobin gene transfer to the adventitia reduces arterial intimal hyperplasia

PURPOSE

The aim of this study was to investigate the feasibility of gene transfer of uteroglobin, a potent anti-inflammatory and immunomodulatory agent, via adenoviral mediated gene transfer to the adventitia in the mouse carotid ligation injury model and also to investigate the efficacy of uteroglobin in reducing neointimal hyperplasia.

METHODS

Forty-five C57bl/6NHSD mice were anesthetized and left common carotid artery ligation was performed. Adenoviral vector encoding the uteroglobin gene (Ad.UG; 15 microl of 1.35 x 10(11) pfu/mL) was applied to the adventitia of the injured artery in 16 mice. In our control groups, 16 mice received adenoviral vector encoding the beta-galactosidase reporter gene (Ad.lacZ; 15 microl of 1.0 x 10(11) pfu/mL) and 13 mice received PBS only. Six mice from each group were sacrificed at 4 days for carotid artery protein extraction and Western blot analysis. The remainder were harvested at 30 days for histologic and morphometric analysis. The intima/media area ratios were calculated for each artery. The results were analyzed and compared using ANOVA and Bonferroni/Dunn post hoc testing.

RESULTS

Two mice from the LacZ group and one from the PBS group died before the 30-day endpoint. Uteroglobin expression was demonstrated in the Ad.UG treated arteries by Western blot analysis. Morphometric analysis demonstrated a statistically significant reduction in the intima/media area ratio of Ad.UG treated carotids compared to controls. There was a reduction of intima/media ratio with Ad. UG treatment of 68% compared to Ad.lacZ treatment (P < 0.0001) and 62% compared to PBS treatment (P = 0.0006). There was no statistical difference between the control groups.

CONCLUSION

Adenoviral mediated gene transfer via the adventitia is an effective mode of gene delivery. Adventitial uteroglobin gene transfer using an adenoviral vector induces uteroglobin protein production and significantly reduces neointimal hyperplasia in the mouse carotid ligation injury model.

Insight into the physiological function(s) of uteroglobin by gene-knockout and antisense-transgenic approaches

To determine the physiological function(s) of uteroglobin (UG), a steroid-inducible, homodimeric, secreted protein, we have generated transgenic mice that either are completely UG-deficient due to UG gene-knockout (UG-KO) or are partially UG-deficient due to the expression of UG antisense RNA (UG-AS). Both the UG-KO and UG-AS mice develop immunoglobulin A (IgA) nephropathy (IgAN), characterized by microhematuria, albuminuria, and renal glomerular deposition of IgA, fibronectin (Fn), collagen, and C3 complement. This phenotype of both UG-KO and UG-AS mice is virtually identical to that of human IgAN, the most common primary glomerulopathy worldwide. The molecular mechanism by which UG prevents this disease in mice appears to center around UG's interaction with Fn. Since Fn, IgA, and UG are present in circulation and high plasma levels of IgA-Fn complex have been reported in human IgAN, we sought to determine whether UG interacts with Fn and prevents Fn-Fn and/or IgA-Fn interactions, essential for abnormal tissue deposition of Fn and IgA. Our coimmunoprecipitation studies uncovered the formation of Fn-UG heteromers in vitro and these heteromers are detectable in the plasma of normal mice, but not UG-KO mice. Further, high plasma levels of IgA-Fn complex, a characteristic of human IgAN patients, were also found in UG-KO mice. Finally, coadministration of UG + Fn or UG + IgA to UG-KO mice prevented glomerular deposition of Fn and IgA, respectively. Our results define a possible molecular mechanism of IgAN and provide insight into at least one important physiological function of UG in maintaining normal renal function in mice.

Uteroglobin binding proteins: regulation of cellular motility and invasion in normal and cancer cells

Uteroglobin (UG) is a multifunctional, secreted protein with anti-inflammatory and antichemotactic properties. While its anti-inflammatory effects, in part, stem from the inhibition of soluble phospholipase A2 (sPLA2) activity, the mechanism(s) of its antichemotactic effects is not clearly understood. Although specific binding of UG on microsomal and plasma membranes has been reported recently, how this binding affects cellular function is not clear. Here, we report that recombinant human UG (hUG) binds to both normal and cancer cells with high affinity (20-35 nM, respectively) and specificity. Affinity cross-linking studies revealed that 125I-hUG binds to the NIH 3T3 cell surface with two proteins of apparent molecular masses of 190 and 49 kDa, respectively. UG affinity chromatography yielded similar results. While both the 190- and 49-kDa proteins were expressed in the heart, liver, and spleen, the lung and trachea expressed only the 190-kDa protein. Some cancer cells (e.g., mastocytoma, sarcoma, and lymphoma) expressed both the 190- and 49-kDa proteins. Further, using functional assays, we found that UG dramatically suppressed the motility and extracellular matrix invasion of both NIH 3T3 and some cancer cells. In order to further characterize the anti-ECM-invasive properties of UG, we induced expression of hUG into cancer cell lines derived from organs that, under physiological circumstances, secrete UG at a high level. Interestingly, it has been reported that a high percentage of the adenocarcinomas arising from the same organs fail to express UG. Our results on induced hUG expression in these cells show that inhibition of motility and ECM invasion requires the expression of both UG and its binding proteins. Taken together, our data define receptor-mediated functions of UG in which this protein regulates vital cellular functions by both autocrine and paracrine pathways.

Rationale for the development of recombinant human CC10 as a therapeutic for inflammatory and fibrotic disease

CC10/uteroglobin is a remarkable protein whose physiological roles have only recently been explored in vivo. Both transgenic mice that have been rendered deficient and humans that have been characterized as deficient in this protein exhibit tendencies toward inflammatory, fibrotic, and oncologic disease, demonstrating the potential of the protein as a therapeutic agent. The protein itself is an excellent candidate for clinical development because of its inherent physical properties. It is relatively small, resistant to proteases, stable to extremes of heat and pH, and can be produced by recombinant methods. The physiological roles of this multifunctional protein continue to be uncovered as research progresses in vitro, in animals, and eventually in humans. The pathways through which CC10 mediates its effects, its receptors, and other family members will be a rich source of exciting research, as well as potential diagnostic and therapeutic agents. This paper is an introductory, noncomprehensive review of some of the scientific and medical rationale in support of CC10-based therapies in selected clinical applications.

Antiflammins. Bioactive peptides derived from uteroglobin

Uteroglobin/Clara cell 10-kDa protein (UG/CC10) is a hormonally regulated small secretory protein that has a variety of in vitro and in vivo pharmacological effects. These include a potent anti-inflammatory activity and inhibitory effects on neutrophil migration, thrombin-induced platelet aggregation, in vitro chemoinvasion, as well as "tumor suppressor"-like effects and other properties. Several mechanisms of action have been proposed for these effects. Pharmacological properties suggest that UG itself or substances derived from it may be used as experimental drugs for several indications. The group of oligopeptides collectively known as "antiflammins" (AFs) were originally described in 1988. Their design was derived from the region of highest sequence similarity between UG and another group of proteins with anti-inflammatory properties, the lipocortins or annexins. Nanomolar concentrations of these peptides can reproduce several of the pharmacological activities of UG, including its in vivo anti-inflammatory effects and inhibition of platelet aggregation. The AFs have been safely and effectively used to suppress inflammation and fibrosis in several animal models. Progress in clarifying the mechanism of action of the AFs may facilitate the structure-based design of a novel class of potent anti-inflammatory, antichemotactic drugs.

Adenoviral-mediated uteroglobin gene transfer inhibits neointimal hyperplasia after balloon injury in the rat carotid artery

OBJECTIVE

Uteroglobin is a protein with potent anti-inflammatory and immunomodulatory effects. We hypothesize that induction of uteroglobin expression in the artery wall by local adenoviral gene transfer will decrease neointimal hyperplasia in the rat carotid artery after balloon injury.

METHODS

Seven male Sprague-Dawley rats underwent balloon injury of the common carotid artery. After the injury, with flow occluded, the artery was instilled with 50 microL of the adenoviral vector encoding uteroglobin gene (Ad.UG) at a concentration of 1.35 x 10(11) pfu/mL (n = 7) or 0.68 x 10(11) pfu/mL (n = 7) (n = 7). Control animals were similarly treated: either an adenovirus encoding for beta-galactosidase gene (Ad.LacZ) at 1 x 10(11) pfu/mL (n = 7) or the phosphate-buffered saline (PBS) vehicle (n = 6) was used. The solution was allowed to dwell for 20 minutes. The rats were humanely killed after 14 days by perfusion fixation, and the carotid arteries were sectioned for analysis with computerized planimetry. The intima-media area ratios were calculated for each artery and compared with analysis of variance with Bonferroni/Dunn post hoc testing. One additional rat from the PBS, Ad.LacZ, and Ad.UG (1.35 x 10(11) pfu/mL) groups was humanely killed 4 days after treatment for carotid artery protein extraction and Western blotting.

RESULTS

Uteroglobin protein production was confirmed in the Ad.UG-treated arteries with Western blotting. Morphometric analysis showed that the Ad.UG group at 1.35 x 10(11) pfu/mL had a significantly lower intima-media area ratio than both the Ad.LacZ (P =.002) and PBS (P =.004) controls. The Ad.UG group at 0.68 x 10(11) pfu/mL was also significantly different from the Ad. LacZ (P =.003) and PBS (P =.006) controls. There was no statistical difference between the two control groups or between the two Ad.UG groups.

CONCLUSION

Adenoviral gene transfer of uteroglobin, delivered intraluminally after arterial injury causes the production of uteroglobin protein and has an inhibitory effect on neointimal accumulation in the rat model.

Uteroglobin reverts the transformed phenotype in the endometrial adenocarcinoma cell line HEC-1A by disrupting the metabolic pathways generating platelet-activating factor

Uteroglobin, originally named blastokinin, is a protein synthesized and secreted by most epithelia, including the endometrium. Uteroglobin has strong anti-inflammatory properties that appear to be due, at least in part, to its inhibitory effect on the activity of the enzyme phospholipase A(2). In addition, recent experimental evidence indicates that uteroglobin exerts antiproliferative and antimetastatic effects in different cancer cells via a membrane receptor. The human endometrial adenocarcinoma cell line HEC-1A does not express uteroglobin. Thus, we transfected HEC-1A cells with human uteroglobin cDNA. The transfectants showed a markedly reduced proliferative potential as assessed by impaired plating efficiency as well as by reduced growth in soft agar. Cytofluorimetric analysis clearly indicated that in uteroglobin-transfected cells the time for completion of the cell cycle was increased. We previously demonstrated that HEC-1A cells actively synthesize platelet-activating factor, one of the products of phospholipase A(2) activity. In addition, we demonstrated that platelet-activating factor stimulates the proliferation of these cells through an autocrine loop. In uteroglobin transfectants, the activity of phospholipase A(2) and platelet-activating factor acetyl-transferase, which are involved in the synthesis of platelet-activating factor, was significantly reduced compared with wild-type and vector-transfected cells (p < 0.05). Our results indicate that enforced expression of uteroglobin in HEC-1A cells markedly reduced their growth potential and significantly impaired the synthesis of platelet-activating factor, an autocrine growth factor for these cells. These data suggest that one possible mechanism for the recently observed antineoplastic properties of uteroglobin may be the inhibition of the synthesis of platelet-activating factor.

Clara cell secretory protein (CC16): characteristics and perspectives as lung peripheral biomarker

Clara cell protein (CC16) is a 15.8-kDa homodimeric protein secreted in large amounts in airways by the non-ciliated bronchiolar Clara cells. This protein increasingly appears to protect the respiratory tract against oxidative stress and inflammation. In vitro, CC16 has been shown to modulate the production and/or the activity of various mediators of the inflammatory response including PLA2, interferon-gamma and tumour necrosis factor-alpha. CC16 has also been found to inhibit fibroblast migration or to bind various endogenous or exogenous substances such as polychlorobiphenyls (PCBs). This protective role is confirmed by studies on transgenic mice, showing that CC16 deficiency is associated with an increased susceptibility of the lung to viral infections and oxidative stress. In humans, a polymorphism of the CC16 gene, localized to a region linked to airway diseases, has recently been discovered in association with an increased risk of developing childhood asthma. Finally, CC16 also presents a major interest as a peripheral marker for assessing the integrity of the lung epithelium. The determination of CC16 in serum is a new non-invasive test to detect Clara cell damage or an increased epithelial permeability in various acute and chronic lung disorders.

Uteroglobin is essential in preventing immunoglobulin A nephropathy in mice

The molecular mechanism(s) of immunoglobulin A (IgA) nephropathy, the most common primary renal glomerular disease worldwide, is unknown. Its pathologic features include hematuria, high levels of circulating IgA-fibronectin (Fn) complexes, and glomerular deposition of IgA, complement C3, Fn and collagen. We report here that two independent mouse models (gene knockout and antisense transgenic), both manifesting deficiency of an anti-inflammatory protein, uteroglobin (UG), develop almost all of the pathologic features of human IgA nephropathy. We further demonstrate that Fn-UG heteromerization, reported to prevent abnormal glomerular deposition of Fn and collagen, also abrogates both the formation of IgA-Fn complexes and their binding to glomerular cells. Moreover, UG prevents glomerular accumulation of exogenous IgA in UG-null mice. These results define an essential role for UG in preventing mouse IgA nephropathy and warrant further studies to determine if a similar mechanism(s) underlies the human disease.

Loss of transformed phenotype in cancer cells by overexpression of the uteroglobin gene

Uteroglobin (UG) is a multifunctional, secreted protein that has receptor-mediated functions. The human UG (hUG) gene is mapped to chromosome 11q12.2-13.1, a region frequently rearranged or deleted in many cancers. Although high levels of hUG expression are characteristic of the mucosal epithelia of many organs, hUG expression is either drastically reduced or totally absent in adenocarcinomas and in viral-transformed epithelial cells derived from the same organs. In agreement with these findings, in an ongoing study to evaluate the effects of aging on UG-knockout mice, 16/16 animals developed malignant tumors, whereas the wild-type littermates (n = 25) remained apparently healthy even after 11/2 years. In the present investigation, we sought to determine the effects of induced-expression of hUG in human cancer cells by transfecting several cell lines derived from adenocarcinomas of various organs with an hUG-cDNA construct. We demonstrate that induced hUG expression reverses at least two of the most important characteristics of the transformed phenotype (i.e., anchorage-independent growth on soft agar and extracellular matrix invasion) of only those cancer cells that also express the hUG receptor. Similarly, treatment of the nontransfected, receptor-positive adenocarcinoma cells with purified recombinant hUG yielded identical results. Taken together, these data define receptor-mediated, autocrine and paracrine pathways through which hUG reverses the transformed phenotype of cancer cells and consequently, may have tumor suppressor-like effects.