Glucocorticoid-dependent uteroglobin synthesis and uteroglobulin mRNA levels in rabbit lung explants cultured in vitro

Detection of serum CC16 by a rapid and ultrasensitive magnetic chemiluminescence immunoassay for lung disease diagnosis

OBJECTIVES

It has been reported that serum Clara cell secreted protein 16 (CC16) is a potential biomarker for lung injury diseases, but currently, there is no other method that is faster, more accurate, or more sensitive being applied in clinical practice apart from ELISA. The current study was designed to established a magnetic nanoparticles chemiluminescence immunoassay (MNPs-CLIA) for highly sensitive automated detection of serum Clara cell secretory protein 16 (CC16), and validated its diagnostic performance for lung disease.

METHODS

The study included the expression of CC16 recombinant protein, the preparation and screening of its monoclonal antibody (MAb), as well as the construction, optimization and analytical evaluation of the MNPs-CLIA method. The clinical application value of this method was investigated by detecting CC16 level in 296 serum samples.

RESULTS

The linear range of the MNPs-CLIA assay system was 0.2-50 ng/mL, and the limit of detection was 0.037 ng/mL. Performance parameters such as specificity, recovery rate, and precision can meet the industry standards of in vitro diagnostic reagents. The established method reveals consistent results with ELISA (R2=0.9962) currently used clinically, and it also exhibits satisfactory diagnostic efficacy of silicosis, chronic obstructive pulmonary disease (COPD), and pulmonary sarcoidosis, with areas under the curve (AUC) of 0.9748, 0.8428 and 0.9128, respectively.

CONCLUSIONS

Our established MNPs-CLIA method has the advantages of automation, high throughput, rapidity, and simplicity, and can be promoted for widely popularized in clinical applications. MNPs-CLIA detection of serum CC16 has efficient diagnostic potentiality for predicting and diagnosing lung diseases.

Quercetin Enhances the Thioredoxin Production of Nasal Epithelial Cells In Vitro and In Vivo

Background: Thioredoxin (TRX) acts as both a scavenger of reactive oxygen species (ROS) and an immuno-modulator. Although quercetin has been shown to favorably modify allergic rhinitis (AR) symptoms, its influence on TRX production is not well defined. The present study was designed to examine whether quercetin could favorably modify AR symptoms via the TRX production of nasal epithelial cells in vitro and in vivo. Methods: Human nasal epithelial cells (HNEpCs) were stimulated with H2O2 in the presence of quercetin. TRX levels in 24-h culture supernatants were examined with ELISA. BALB/c male mice were intraperitoneally sensitized to ovalbumin (OVA) and intranasally challenged with OVA every other day, beginning seven days after the final sensitization. The mice were orally administered quercetin once a day for five consecutive days, beginning seven days after the final sensitization. Nasal symptoms were assessed by counting the number of sneezes and nasal rubbing behaviors during a 10-min period immediately after the challenge. TRX levels in nasal lavage fluids obtained 6 h after the challenge were examined by ELISA. Results: Treatment with 1.0 nM quercetin increased H2O2-induced TRX levels. The oral administration of 20.0 mg/kg of quercetin significantly inhibited nasal symptoms after the challenge. The same dose of quercetin significantly increased TRX levels in nasal lavage fluids. Conclusions: Quercetin's ability to increase TRX production may account, at least in part, for its clinical efficacy toward AR.

Club Cell Protein 16 (CC16) Augmentation: A Potential Disease-modifying Approach for Chronic Obstructive Pulmonary Disease (COPD)

INTRODUCTION

Club cell protein 16 (CC16) is the most abundant protein in bronchoalveolar lavage fluid. CC16 has anti-inflammatory properties in smoke-exposed lungs, and chronic obstructive pulmonary disease (COPD) is associated with CC16 deficiency. Herein, we explored whether CC16 is a therapeutic target for COPD.

AREAS COVERED

We reviewed the literature on the factors that regulate airway CC16 expression, its biologic functions and its protective activities in smoke-exposed lungs using PUBMED searches. We generated hypotheses on the mechanisms by which CC16 limits COPD development, and discuss its potential as a new therapeutic approach for COPD.

EXPERT OPINION

CC16 plasma and lung levels are reduced in smokers without airflow obstruction and COPD patients. In COPD patients, airway CC16 expression is inversely correlated with severity of airflow obstruction. CC16 deficiency increases smoke-induced lung pathologies in mice by its effects on epithelial cells, leukocytes, and fibroblasts. Experimental augmentation of CC16 levels using recombinant CC16 in cell culture systems, plasmid and adenoviral-mediated over-expression of CC16 in epithelial cells or smoke-exposed murine airways reduces inflammation and cellular injury. Additional studies are necessary to assess the efficacy of therapies aimed at restoring airway CC16 levels as a new disease-modifying therapy for COPD patients.

The transcription factor SOX17 is involved in the transcriptional control of the uteroglobin gene in rabbit endometrium

The transcription of the uteroglobin gene (ug) is induced by progesterone in the rabbit endometrium, primarily through the binding of the progesterone receptor to the distal region of the ug promoter. However, other transcription factors participate in the progesterone action. The proximal ug promoter contains several putative consensus sequences for the binding of various progesterone-dependent endometrial nuclear factors (Perez Martinez et al. [1996] Arch Biochem Biophys 333: 12-18), suggesting that several transcription factors might be implicated in the hormonal induction of ug. We report here that one of these progesterone-dependent factors specifically binds to the sequence CACAATG (-183/-177) of the rabbit ug promoter. This sequence (hereafter called element G') is very similar to the consensus sequence for binding of the SOX family of transcription factors. Mutation of the element G' reduced transcription from the ug promoter in transient expression experiments. The endometrial factor was purified and analyzed by nano-liquid chromatography and ion trap coupled mass spectrometry yielding two partial amino acid sequences corresponding to a region of SOX17 that is highly conserved inter-species. This identification was confirmed by immunological techniques using a specific anti-SOX17 antibody. In agreement with the above findings, overexpression of SOX17 in transfected endometrial cells increased transcription from the ug promoter. SOX17 gradually accumulated in the nucleus in vivo concomitant with the induction of ug expression by progesterone in the endometrium. Thus, these findings implicate, for the first time, SOX17 in the transcriptional control of rabbit ug.

Low levels of CC16 in nasal fluid of children with birch pollen-induced rhinitis

BACKGROUND

Clara cell protein 16 (CC16; secretoglobin 1A1) is an anti-inflammatory protein mainly expressed in the epithelial cells in the airways.

OBJECTIVE

To compare the levels of CC16 in nasal lavage (NAL) from children with intermittent allergic rhinitis and healthy controls and to study the effect of a local steroid.

METHODS

Thirty schoolchildren with birch pollen allergy and 30 healthy controls from the same schools were included in the study. The NAL fluid was collected before the season, during the birch pollen season and, for the patients, after 1 week of treatment with a local steroid. Symptom scores were obtained on every occasion. CC16 and eosinophil cationic protein (ECP) were analyzed with enzyme-linked immunosorbent assay.

RESULTS

The nasal fluid levels of CC16 were significantly lower in patients than in controls, before and during pollen season. Before the season, the median CC16 concentrations were 9.1 (range 1.1-117) microg/l in patients and 25.7 (6.1-110.2) microg/l in controls. During the season, the median CC16 concentrations in nasal fluid were 12.9 (2.3-89.7) microg/l in the allergic children and 22.0 (9.5-90.1) microg/l in the healthy controls (P = 0.0005). Symptom scores, nasal fluid eosinophils and ECP were higher in patients during the season. Treatment with a local steroid did not change the CC16 levels.

CONCLUSIONS

Nasal fluid CC16 levels were lower in children with birch pollen-induced allergic rhinitis than in healthy controls both before and during the pollen season. We speculate that reduction in anti-inflammatory activity by CC16 may contribute to the pathogenesis of allergic rhinitis.

Two progesterone-dependent endometrial nuclear factors bind to an E-box in the rabbit uteroglobin gene promoter: involvement in tissue-specific transcription

We studied the implications of progesterone-dependent transcription factors in the hormonal and tissue-specific induction of the uteroglobin gene (ug) in the rabbit endometrium. Previously, we have observed the interaction of two progesterone-dependent endometrial nuclear proteins (TRBPs) with sequences downstream from the ug TATA box. Using electrophoretic mobility shift assays (EMSA) we show here that TRBPs specifically interacted with an E-box localized almost immediately downstream from the ug TATA box. UV crosslinking of affinity-purified TRBPs to the radiolabeled oligonucleotide probe confirmed that these factors were proteins with molecular mass of about 40-50 kDa. Ferguson's analysis of the Mr of the DNA-TRBP complexes suggested that TRBPs interacted with the E-box either as homo- or heterodimers. This interaction did not result in detectable bending of the DNA. EMSA analysis with nuclear extracts from different rabbit tissues suggested that TRBPs might be endometrium-specific nuclear factors. Involvement of the E-box in the tissue-specific transcription from the ug promoter was assessed by transient expression experiments using different cell lines transfected with a reporter gene driven by the ug promoter which contained either the intact E-box or a mutated version that completely abolished its interaction with TRBPs. These experiments indicated that, in all cell lines of nonendometrial lineage, destruction of the E-box increased transcription from the ug promoter, whereas in two cell lines of endometrial origin this mutation either had no appreciable effect or slightly reduced the transcription from the promoter. Thus, this E-box and endometrial helix-loop-helix proteins might be involved in the hormonal and tissue-specific regulation of ug transcription.

Combinatorial action of HNF3 and Sp family transcription factors in the activation of the rabbit uteroglobin/CC10 promoter

It has been reported that respiratory epithelium-specific transcription is mediated by thyroid transcription factor 1 and members of the HNF3/forkhead family of transcription factors. Here, we show that the uteroglobin/Clara cell 10-kDa promoters from rabbit and man are regulated by HNF3alpha and HNF3beta but not by HFH-4 and TTF-1. We have identified two HNF3-responsive elements in the rabbit uteroglobin/CC10 promoter located around 95 and 130 base pairs upstream of the transcriptional start site. Both elements contribute to promoter activity in H441 cells expressing uteroglobin/CC10 and HNF3alpha. Gene transfer experiments into Drosophila Schneider cells that lack many mammalian transcription factor homologs revealed that HNF3alpha and HNF3beta on their own cannot activate the uteroglobin/CC10 promoter. However, HNF3alpha and HNF3beta strongly enhanced Sp1-mediated promoter activation. Synergistic activation by HNF3alpha and Sp1 was absolutely dependent on the integrity of two Sp1 sites located at around -65 and -230. We show further that multiple activation domains of Sp1 are required for cooperativity with HNF3alpha. These studies demonstrate that transcription from the rabbit uteroglobin/CC10 promoter in lung epithelium is controlled by the combinatorial action of the cell-specific factor HNF3alpha and the ubiquitous factor Sp1.

Molecular cloning of the cDNA and the promoter of the hamster uteroglobin/Clara cell 10-kDa gene (ug/cc10): tissue-specific and hormonal regulation

Using the polymerase chain reaction on first-strand cDNAs from lung as well as on genomic DNA, we have cloned and sequenced both the cDNA and 1.5 kb of the promoter of the gene coding for hamster uteroglobin/Clara cell 10-kDa protein (UG/CC10), a secretory protein mainly synthesized in the pulmonary Clara cells. The amino acid sequence deduced from the cDNA indicated a preprotein of 96 residues, 19 of which corresponded to the signal peptide. The promoter region contained transcriptional regulatory elements conserved between species. Northern blot and S1 resistance assays detected high expression of ug/cc10 in lung but not at all in other tissues. Expression in lung was positively controlled by glucocorticoids and was also subjected to a biphasic developmental regulation after birth. In agreement with the tissue-specific expression observed in vivo, the hamster promoter preferentially directed the expression of a reporter gene in cells derived from Clara cells. The results indicated that the tissue-specific expression and the regulation of ug/cc10 varied considerably between species but all of them had a high expression in lung.

Binding of YY1 to a site overlapping a weak TATA box is essential for transcription from the uteroglobin promoter in endometrial cells

The gene for rabbit uteroglobin codes for a small calcium-, steroid-, and biphenyl metabolite-binding homodimeric protein which is expressed in a variety of epithelial cell types such as Clara cells (lung) and the glandular and luminal cells of the endometrium. One important region mediating its efficient transcription in a human endometrium-derived cell line, Ishikawa, is centered around a noncanonical TATA box. Two factors, TATA core factor (TCF), expressed in cell lines derived from uteroglobin-expressing tissues, and the ubiquitously expressed TATA palindrome factor, bind to the DNA major groove at two adjacent sites within this region. Here, we report the identification of the TATA palindrome factor as the transcription/initiation factor YY1 by microsequencing of the biochemically purified factor from HeLa cells. The binding site for YY1 within the uteroglobin gene is unique in its sequence and its location overlapping a weak TATA box (TACA). Binding of YY1 was required for efficient transcription in TCF-positive Ishikawa cells, which responded only weakly to a change of TACA to TATA, although in vitro binding affinity for the TATA-box-binding protein increased by 1 order of magnitude. In contrast, in CV-1 cells, lacking TCF, binding of YY1 was not required for transcription in the context of a wild-type TACA box, whereas a change from TACA to TATA led to significantly increased reporter gene expression. DNA binding data exclude a role of YY1 in stabilizing the interaction of the TATA-box-binding protein with the uteroglobin promoter. We conclude that cell lines derived from uteroglobin-expressing tissues overcome the weak TATA box with the help of auxiliary factors, one of them being YY1.

Binding of uteroglobin to microsomes and plasmatic membranes

Microsomes and plasmatic membranes from rat liver bind radioactive uteroglobin (UG) in vitro with high affinity (Kd = 1.7 x 10(-10) M. The binding is saturable and specific and dependent on previous reduction of UG with dithiothreitol. Microsomes from rat spleen or lung or from rabbit endometrium also possess a similar ability. Binding capacity is not affected by previous treatment of microsomes with phospholipase A2 or peptide-N-glycosidase F but is lost after brief treatment with trypsin. The complex formed between UG and the binding component can be solubilized from microsomes with 5 mM CHAPS and it elutes with an apparent Mr of 90,000 in a Sephacryl 200 column. The complex is resistant to 8 M urea but is completely dissociated by Triton X-100. The UG-binding protein(s) has been partially purified from solubilized microsomes and membranes by affinity chromatography. The results are discussed in relation to a possible physiological effect of UG on cellular membranes.

Two distinct factors bind to the rabbit uteroglobin TATA-box region and are required for efficient transcription

The rabbit uteroglobin gene is expressed in a variety of epithelial cell types like the lung Clara cells and the glandular and luminal epithelial cells of the endometrium. Expression in Clara cells is on a high constitutive level, whereas expression in the rabbit endometrium is under tight hormonal control. One important element of the rabbit uteroglobin gene mediating its efficient transcription in two epithelial cell lines from human endometrium (Ishikawa) and lung (NCI-H441) is its noncanonical TATA box (TACA). Here, we show that two factors (TATA core factor [TCF] and TATA palindrome factor [TPF]) different from the TATA-box binding protein bind to the DNA major groove at two adjacent sites within the uteroglobin TATA-box region and that one of them (TCF) is specifically expressed in cell lines derived from uteroglobin-expressing tissues. The binding sites for TCF and TPF, respectively, are both required for efficient transcription in Ishikawa and NCI-H441 cells. Mutation of the TACA box, which we show is a poor TATA box in functional terms, to a canonical TATA motif does not affect TCF and TPF binding. Therefore, we suggest that the function of the unusual cytosine could be to reduce rabbit uteroglobin expression in cells lacking TCF and that the interaction of TATA-box binding protein with the weak TACA site is facilitated in TCF- and TPF-positive cells.

Two distinct factors bind to the rabbit uteroglobin TATA-box region and are required for efficient transcription

The rabbit uteroglobin gene is expressed in a variety of epithelial cell types like the lung Clara cells and the glandular and luminal epithelial cells of the endometrium. Expression in Clara cells is on a high constitutive level, whereas expression in the rabbit endometrium is under tight hormonal control. One important element of the rabbit uteroglobin gene mediating its efficient transcription in two epithelial cell lines from human endometrium (Ishikawa) and lung (NCI-H441) is its noncanonical TATA box (TACA). Here, we show that two factors (TATA core factor [TCF] and TATA palindrome factor [TPF]) different from the TATA-box binding protein bind to the DNA major groove at two adjacent sites within the uteroglobin TATA-box region and that one of them (TCF) is specifically expressed in cell lines derived from uteroglobin-expressing tissues. The binding sites for TCF and TPF, respectively, are both required for efficient transcription in Ishikawa and NCI-H441 cells. Mutation of the TACA box, which we show is a poor TATA box in functional terms, to a canonical TATA motif does not affect TCF and TPF binding. Therefore, we suggest that the function of the unusual cytosine could be to reduce rabbit uteroglobin expression in cells lacking TCF and that the interaction of TATA-box binding protein with the weak TACA site is facilitated in TCF- and TPF-positive cells.

Binding of retinoids to uteroglobin

Uteroglobin, a progesterone-binding secretory protein, was shown to bind retinoic acid and retinol in a non-saturable manner, at least up to concentrations of retinoids of 20 microM. Binding is increased about 10-fold by previous reduction of uteroglobin with 10 mM dithiothreitol and it is not affected by previous saturation of the progesterone binding site, suggesting different binding sites for the steroid and the retinoids. The results are discussed in relation to a possible physiological role for this protein.

Ontogeny of a human polychlorinated biphenyl-binding protein. Level of expression in tracheal aspirates in bronchopulmonary dysplasia

A human lung polychlorinated biphenyl binding protein (PCB-BP,M(r) 13 kd) has recently been purified from lavage fluid. Polyclonal monospecific antibodies against PCB-BP were produced and used for immunohistochemical staining in sections of human lung tissue. PCB-BP was found to localize preferentially to the nonciliated (Clara) cells of the lung, whereas the alveolar cells and ciliated cells of the larger airways were devoid of staining. Tracheal aspirates from infants receiving mechanical ventilation were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis separation and Western immunoblotting. The antibodies to human PCB-BP detected a single band of the expected molecular weight, and a quantitative analysis of the ontogeny of PCB-BP in tracheal aspirates was performed by construction of Western immunoblot standard curves. A significant increase in the levels of PCB-BP in late gestation (gestational weeks 39 to 41) was demonstrated. In similar experiments, levels of PCB-BP in tracheal aspirates obtained from infants with bronchopulmonary dysplasia (BPD) at the postconceptional age of less than 38 weeks were found to be significantly elevated as compared with a normal study group of similar gestational age (21.8 +/- 4.8 vs 3.1 +/- 0.8 ng of PCB-BP per microgram of total protein, p < 0.005). It is suggested that the high levels of PCB-BP at the postconceptional age of less than 38 weeks observed in infants with BPD may reflect inflammatory injury and regeneration of airway epithelium, associated with proliferation of Clara cells.

Detection and hormonal regulation of the mRNA for cytosolic phosphoenolpyruvate carboxykinase in rat lung

We have studied the presence of the messenger RNA (mRNA) for the cytosolic enzyme, phosphoenolpyruvate carboxykinase (PEPCK), in rat lung by Northern blot hybridization to a complementary DNA (cDNA) probe. Lung from normal rats contained substantial amounts of this mRNA, although its relative concentration was approximately six times lower than in liver. Fasting produced an eightfold increase in the content of the enzyme mRNA in lung, which could be reverted to normal values by glucose refeeding. Induced diabetes also resulted in a sevenfold increase of the levels of PEPCK mRNA in lung. Dexamethasone, thyroid hormone, dibutyryl cyclic adenosine monophosphate (cAMP), histamine, and serotonin also induced important accumulations of the enzyme mRNA without affecting the concentration of beta-tubulin mRNA measured as reference. Thus, the PEPCK gene appears to be regulated in a similar manner in lung and liver. The results suggest that PEPCK may be involved in lung metabolism in starvation, diabetes, and other specific hormonal situations.

Purification and level of expression in bronchoalveolar lavage of a human polychlorinated biphenyl (PCB)-binding protein: evidence for a structural and functional kinship to the multihormonally regulated protein uteroglobin

A human lung polychlorinated biphenyl (PCB)-binding protein was purified by sequential chromatography of lavage fluid incubated with the tritium-labeled, high-affinity ligand, 4,4'-bis(methylsulfonyl)-2,2',5,5'-tetrachlorobiphenyl. From sodium dodecyl sulfate polyacrylamide gel electrophoresis gradient gels, it was evident that a single band with an approximate molecular weight of 13 kD was present in the eluate from the final chromatographic step. Antibodies raised against the human lung PCB-binding protein detected a single band of corresponding size in lavage fluid in immunoblotting experiments. Furthermore, the antibodies detected significantly higher levels of the lung PCB-binding protein in lavage fluid from nonsmokers as compared to smokers. The purified protein was sequenced, and an alignment of the obtained aminoterminal amino acid residues of the human lung PCB-binding protein to uteroglobin and to a rat lung PCB-binding protein revealed an overall positional identity of approximately 45%. The amino acids suggested to participate in ligand binding of uteroglobin were extensively conserved in the PCB-binding proteins. Thus, we conclude that we have purified and raised antibodies against a human lung PCB-binding protein and that it has a structural as well as a functional kinship to the steroid-binding and multihormonally regulated rabbit protein uteroglobin.

Cell-specific, developmentally and hormonally regulated expression of the rabbit uteroglobin transgene and the endogenous mouse uteroglobin gene in transgenic mice

We have generated a transgenic mouse line by introducing the rabbit uteroglobin gene with 4 kb of 5'-flanking DNA and 1 kb of 3'-flanking DNA into the mouse germ line via microinjection into fertilized oocytes. Expression of the rabbit uteroglobin transgene was examined and compared with the endogenous mouse uteroglobin gene. Both genes are expressed in the lung, male genital tract and uterus. In the lung, mRNA expression is enhanced by glucocorticoids and restricted to the Clara cells that line terminal and respiratory bronchioli. During embryonic lung development, transcripts are first detected at day 17. Expression in the uterus is restricted to the glandular epithelium and can be induced by sequential treatment with estrogens and progesterone. In the uterus of these pseudopregnant mice the level of rabbit uteroglobin transcripts is higher than that of the mouse endogenous uteroglobin transcripts. In the male genital tract, expression of both genes is restricted to the epithelial layers of the vesicular gland, vas deferens and epididymis. Our results indicate that the rabbit uteroglobin gene together with 4 kb of 5'-flanking DNA and 1 kb of 3'-flanking DNA contains the information required for cell type-specific, developmentally, and hormonally regulated expression.

Localization of an estrogen receptor binding site near the promoter of the uteroglobin gene

By means of a DNA-cellulose competitive binding assay, we have studied the interaction of the estrogen receptor with genomic fragments of the estrogen responsive rabbit uteroglobin gene. The fragments spanned from 3255 bp upstream to 1754 bp downstream of the initiation site. Only a fragment (-396/+8) showed strong affinity for the receptor. Within this fragment a unique palindromic sequence (GGTCAccaTGCCC) was found which is very similar to the canonical consensus sequence for the estrogen receptor. A synthetic oligonucleotide of that structure specifically competed for the binding of the receptor to DNA-cellulose.

Tissue-specific expression, hormonal regulation and 5'-flanking gene region of the rat Clara cell 10 kDa protein: comparison to rabbit uteroglobin

The amino acid sequence of rat Clara Cell 10 kDa secretory protein (CC10) shows 55% identity to rabbit uteroglobin. In order to define the relationship between rat CC10 and rabbit uteroglobin in detail, the tissue-specific expression and hormonal regulation of rat CC10 mRNA was analyzed. We report that like rabbit uteroglobin, rat CC10 mRNA is expressed in lung and esophagus, as well as in uteri of estrogen- and progesterone-treated females. Expression of CC10 mRNA in lung is regulated by glucocorticoids. The similarity in expression pattern of rat CC10 mRNA and rabbit uteroglobin mRNA is reflected by a striking similarity in the 5'-flanking regions of the two genes. Despite this overall similarity, two regions of 0.3 kb and 2.1 kb are absent in the rat CC10 upstream gene region. The larger region includes a cluster of hormone receptor binding sites, believed to be responsible for differential regulation of rabbit uteroglobin by glucocorticoids and progesterone. Thus, while the sequence identities in the coding and 5'-flanking regions point towards a common ancestor for the uteroglobin and CC10 gene, later events (deletions/insertions) might have caused species-specific differences in their regulation.

In vitro biosynthesis and secretion of rabbit epididymal secretory proteins: regulation by androgens

The biosynthesis and secretion of epididymal proteins were studied in an in vitro system using explants from rabbit epididymis cultured in a defined medium. Epididymal explants actively incorporated [35S]methionine into cellular proteins, about 7% of them being secreted into the medium. SDS-PAGE of the labeled proteins secreted to the medium showed regional differences in their synthesis and secretion along the epididymal tract. Castration resulted in the inhibition of the synthesis and secretion of at least two polypeptides of Mr 150,000 and 21,000, but at the same time induced the appearance of other polypeptides. Immunoprecipitations with a specific antibody indicated that the variations in the amounts of the secreted 21 kDa component were associated with differences in its rate of synthesis. Epididymis from immature rabbits synthesized some polypeptides that are repressed in the adult state. The results suggest a dual effect of testosterone on rabbit epididymal secretory proteins.

Purification and partial amino acid sequence of human urine protein 1. Evidence for homology with rabbit uteroglobin

We describe the purification of Urine Protein 1 (UP1), a 14-16 kDa protein which occurs in the urine of patients with renal failure, and therefore may originate from the plasma or kidney. Amino acid sequencing shows that UP1 has significant homology with rabbit uteroglobin, a secretory protein of the uterus (during pregnancy) and lungs (both sexes), and previously identified only in lagomorphs (rabbits, hares, pikas). The finding of a human uteroglobin-like protein, which can be purified from a readily available source, may provide further opportunities to elucidate the, as yet, uncertain physiological functions of uteroglobin.

Evidence for the identity of anti-proteinase pulmonary protein CCSP and uteroglobin

Purified Clara cell secretory protein (CCSP) from rabbit lung was analyzed by SDS gel electrophoresis, and immunoblotting with a specific anti-uteroglobin antibody as well as for its ability to bind [3H]progesterone. The results obtained indicate that proteins CCSP and uteroglobin are identical.

Detection of a rabbit uteroglobin-like protein in human neonatal tracheobronchial washings

Uteroglobin is a steroid hormone dependent, low molecular weight, secretory protein with many immunomodulatory properties. Immunomodulation by this protein may, at least in part, be related to its inhibitory effects on phospholipase A2 activity. Although uteroglobin is conclusively found in the rabbit, its presence in the human is controversial. Here, we present biochemical and immunological evidence for the detection of a uteroglobin-like protein in the wet epithelial living of the respiratory tract of human neonates. Because inhibition of phospholipase A2 may modulate tissue eicosanoid levels and since many eicosanoids (i.e. prostaglandins and leukotrienes etc.) are well known regulators of smooth muscle contractility, cellular migration and inflammatory processes, the discovery of this protein in the human respiratory tract may have important physiological implications.

Testosterone induces the expression of the uteroglobin gene in rabbit epididymis

Uteroglobin was characterized in the rabbit epididymis by radioimmunoassay and electrophoretic determinations, as well as by analysis of its mRNA by means of 'Northern blot' and nuclease-S1 mapping. Treatment of sexually immature rabbits with testosterone during 5 days increased up to 8-fold the concentrations of both uteroglobin and its mRNA in the epididymis. The amounts of beta-tubulin mRNA, measured as reference, remained unchanged after the hormonal treatment. The synthesis of uteroglobin occurred mainly in the middle region of the epididymis, progressively decreasing toward the distal part of the organ. Uteroglobin was not detected in the testis by radioimmunoassay. The results are discussed in relation to a possible role of uteroglobin in the reproductive functions.

Nucleotide and derived amino acid sequences of a cDNA coding for pre-uteroglobin from the lung of the hare (Lepus capensis)

An almost full-length cDNA coding for pre-uteroglobin from hare lung was cloned and sequenced. The derived amino acid sequence indicated that hare pre-uteroglobin contained 91 amino acids, including a signal peptide of 21 residues. Comparison of the nucleotide sequence of hare pre-uteroglobin cDNA with that previously reported for the rabbit gene indicated five silent point substitutions and six others leading to amino acid changes in the coding region. The untranslated regions of both pre-uteroglobin mRNAs were very similar. The amino acid changes observed are discussed in relation to the different progesterone-binding abilities of both homologous proteins.

Primary structure of rabbit lung uteroglobin as deduced from the nucleotide sequence of a cDNA

Double-stranded cDNA was synthesized from partially purified uteroglobin mRNA from rabbit lung. A cDNA coding for lung uteroglobin was then cloned in the plasmid pUC18 and both the nucleotide sequence and the derived amino acid sequence were determined. This allowed us to demonstrate unequivocally that uteroglobins from lung and uterus are identical proteins.