Severe fibronectin-deposit renal glomerular disease in mice lacking uteroglobin

Serum and urine profiling by high-throughput TMT-based proteomics for the investigation of renal dysfunction in canine babesiosis

Canine babesiosis is a tick-borne disease caused by Babesia canis, with acute kidney injury as one of the common complications. In the study 8 healthy control dogs and 22 dogs with naturally occurring babesiosis were enrolled, with the aim to analyse differences in serum and urinary proteomes between healthy dogs and dogs with different degree of renal dysfunction in babesiosis using a label-based high-throughput quantitative proteomic approach. In serum, 58 proteins were found differentially abundant between healthy controls and groups of dogs with different degrees of renal dysfunction in babesiosis, while in urine there were 259 differentially abundant proteins. In addition, altered biological pathways were detected in the diseased dogs using bioinformatics tools and validation of several candidate biomarkers was performed. SIGNIFICANCE: The main aim of this comprehensive study was to perform analyses of serum and urinary proteomes of dogs with renal dysfunction in babesiosis compared to healthy dogs using, for the first time, a high-throughput proteomic method and functional enrichment analyses. Serum and urine samples of the same dogs were investigated in order to gain a more complete picture of pathologic changes taking place in renal dysfunction in babesiosis. We highlighted two putative biomarkers validated herein which could be of importance for early diagnosis of renal dysfunction in canine babesiosis, as they are easily accessible from urine and their concentration rises before the appearance of azotaemia: urinary neutrophil gelatinase-associated lipocalin (NGAL) and urinary liver-type fatty acid-binding protein (L-FABP).

Secretoglobins in the big picture of immunoregulation in airway diseases

The proteins of the secretoglobin (SCGB) family are expressed by secretory tissues of barrier organs. They are embedded in immunoregulatory and anti-inflammatory processes of airway diseases. This review particularly illustrates the immune regulation of SCGBs by cytokines and their implication in the pathophysiology of airway diseases. The biology of SCGBs is a complex topic of increasing importance, as they are highly abundant in the respiratory tract and can also be detected in malignant tissues and as elements of immune control. In addition, SCGBs react to cytokines, they are embedded in Th1 and Th2 immune responses, and they are expressed in a manner dependent on cell maturation. The big picture of the SCGB family identifies these factors as critical elements of innate immune control at the epithelial barriers and highlights their potential for diagnostic assessment of epithelial activity. Some members of the SCGB family have so far only been superficially examined, but have high potential for translational research.

CC16 Binding to α4β1 Integrin Protects against Mycoplasma pneumoniae Infection

Rationale CC16 (club cell secretory protein) is a pneumoprotein produced predominantly by pulmonary club cells. Circulating CC16 is associated with protection from the inception and progression of the two most common obstructive lung diseases (asthma and chronic obstructive pulmonary disease). Objectives Although exact mechanisms remain elusive, studies consistently suggest a causal role of CC16 in mediating antiinflammatory and antioxidant functions in the lung. We sought to determine any novel receptor systems that could participate in CC16's role in obstructive lung diseases. Methods Protein alignment of CC16 across species led to the discovery of a highly conserved sequence of amino acids, leucine-valine-aspartic acid (LVD), a known integrin-binding motif. Recombinant CC16 was generated with and without the putative integrin-binding site. A Mycoplasma pneumoniae mouse model and a fluorescent cellular adhesion assay were used to determine the impact of the LVD site regarding CC16 function during live infection and on cellular adhesion during inflammatory conditions. Measurements and Main Results CC16 bound to integrin α₄β₁), also known as the adhesion molecule VLA-4 (very late antigen 4), dependent on the presence of the LVD integrin-binding motif. During infection, recombinant CC16 rescued lung function parameters both when administered to the lung and intravenously but only when the LVD integrin-binding site was intact; likewise, neutrophil recruitment during infection and leukocyte adhesion were both impacted by the loss of the LVD site. Conclusions We discovered a novel receptor for CC16, VLA-4, which has important mechanistic implications for the role of CC16 in circulation as well as in the lung compartment.

ACVR2B antagonism as a countermeasure to multi-organ perturbations in metastatic colorectal cancer cachexia

BACKGROUND

Advanced colorectal cancer (CRC) is often accompanied by the development of liver metastases, as well as cachexia, a multi-organ co-morbidity primarily affecting skeletal (SKM) and cardiac muscles. Activin receptor type 2B (ACVR2B) signalling is known to cause SKM wasting, and its inhibition restores SKM mass and prolongs survival in cancer. Using a recently generated mouse model, here we tested whether ACVR2B blockade could preserve multiple organs, including skeletal and cardiac muscle, in the presence of metastatic CRC.

METHODS

NSG male mice (8 weeks old) were injected intrasplenically with HCT116 human CRC cells (mHCT116), while sham-operated animals received saline (n = 5-10 per group). Sham and tumour-bearing mice received weekly injections of ACVR2B/Fc, a synthetic peptide inhibitor of ACVR2B.

RESULTS

mHCT116 hosts displayed losses in fat mass ( - 79%, P < 0.0001), bone mass ( - 39%, P < 0.05), and SKM mass (quadriceps: - 22%, P < 0.001), in line with reduced muscle cross-sectional area ( - 24%, P < 0.01) and plantarflexion force ( - 28%, P < 0.05). Further, despite only moderately affected heart size, cardiac function was significantly impaired (ejection fraction %: - 16%, P < 0.0001; fractional shortening %: - 25%, P < 0.0001) in the mHCT116 hosts. Conversely, ACVR2B/Fc preserved fat mass ( + 238%, P < 0.001), bone mass ( + 124%, P < 0.0001), SKM mass (quadriceps: + 31%, P < 0.0001), size (cross-sectional area: + 43%, P < 0.0001) and plantarflexion force ( + 28%, P < 0.05) in tumour hosts. Cardiac function was also completely preserved in tumour hosts receiving ACVR2B/Fc (ejection fraction %: + 19%, P < 0.0001), despite no effect on heart size. RNA sequencing analysis of heart muscle revealed rescue of genes related to cardiac development and contraction in tumour hosts treated with ACVR2B/Fc.

CONCLUSIONS

Our metastatic CRC model recapitulates the multi-systemic derangements of cachexia by displaying loss of fat, bone, and SKM along with decreased muscle strength in mHCT116 hosts. Additionally, with evidence of severe cardiac dysfunction, our data support the development of cardiac cachexia in the occurrence of metastatic CRC. Notably, ACVR2B antagonism preserved adipose tissue, bone, and SKM, whereas muscle and cardiac functions were completely maintained upon treatment. Altogether, our observations implicate ACVR2B signalling in the development of multi-organ perturbations in metastatic CRC and further dictate that ACVR2B represents a promising therapeutic target to preserve body composition and functionality in cancer cachexia.

Lung Secretoglobin Scgb1a1 Influences Alveolar Macrophage-Mediated Inflammation and Immunity

Alveolar macrophage (AM) is a mononuclear phagocyte key to the defense against respiratory infections. To understand AM’s role in airway disease development, we examined the influence of Secretoglobin family 1a member 1 (SCGB1A1), a pulmonary surfactant protein, on AM development and function. In a murine model, high-throughput RNA-sequencing and gene expression analyses were performed on purified AMs isolated from mice lacking in Scgb1a1 gene and were compared with that from mice expressing the wild type Scgb1a1 at weaning (4 week), puberty (8 week), early adult (12 week), and middle age (40 week). AMs from early adult mice under Scgb1a1 sufficiency demonstrated a total of 37 up-regulated biological pathways compared to that at weaning, from which 30 were directly involved with antigen presentation, anti-viral immunity and inflammation. Importantly, these pathways under Scgb1a1 deficiency were significantly down-regulated compared to that in the age-matched Scgb1a1-sufficient counterparts. Furthermore, AMs from Scgb1a1-deficient mice showed an early activation of inflammatory pathways compared with that from Scgb1a1-sufficient mice. Our in vitro experiments with AM culture established that exogenous supplementation of SCGB1a1 protein significantly reduced AM responses to microbial stimuli where SCGB1a1 was effective in blunting the release of cytokines and chemokines (including IL-1b, IL-6, IL-8, MIP-1a, TNF-a, and MCP-1). Taken together, these findings suggest an important role for Scgb1a1 in shaping the AM-mediated inflammation and immune responses, and in mitigating cytokine surges in the lungs.

The Club Cell Marker SCGB1A1 Downstream of FOXA2 is Reduced in Asthma

Human SCGB1A1 protein has been shown to be significantly reduced in BAL, sputum, and serum from humans with asthma as compared with healthy individuals. However, the mechanism of this reduction and its functional impact have not been entirely elucidated. By mining online datasets, we found that the mRNA of SCGB1A1 was significantly repressed in brushed human airway epithelial cells from individuals with asthma, and this repression appeared to be associated with reduced expression of FOXA2. Consistently, both Scgb1A1 and FoxA2 were downregulated in an ovalbumin-induced mouse model of asthma. Furthermore, compared with wild-type mice, Scgb1a1 knockout mice had increased airway hyperreactivity and inflammation when they were exposed to ovalbumin, confirming the antiinflammatory role of Scgb1a1 in protection against asthma phenotypes. To search for potential asthma-related stimuli of SCGB1A1 repression, we tested T-helper cell type 2 cytokines. Both IL-4 and IL-13 repressed epithelial expression of SCGB1A1 and FOXA2. Importantly, infection of epithelial cells with human rhinovirus similarly reduced expression of these two genes, which suggests that FOXA2 may be the common regulator of SCGB1A1. To establish the causal role of reduced FOXA2 in SCGB1A1 repression, we demonstrated that FOXA2 was required for SCGB1A1 expression at baseline. FOXA2 overexpression was sufficient to drive promoter activity and expression of SCGB1A1 and was also able to restore the repressed SCGB1A1 expression in IL-13-treated or rhinovirus-infected cells. Taken together, these findings suggest that low levels of epithelial SCGB1A1 in asthma are caused by reduced FOXA2 expression.

Muc5b-deficient mice develop early histological lung abnormalities

Gel-forming mucins are the main organic component responsible for physical properties of the mucus hydrogels. While numerous biological functions of these mucins are well documented, specific physiological functions of each mucin are largely unknown. To investigate in vivo functions of the gel-forming mucin Muc5b, which is one of the major secreted airway mucins, along with Muc5ac, we generated mice in which Muc5b was disrupted and maintained in the absence of environmental stress. Adult Muc5b-deficient mice displayed bronchial hyperplasia and metaplasia, interstitial thickening, alveolar collapse, immune cell infiltrates, fragmented and disorganized elastin fibers and collagen deposits that were, for approximately one-fifth of the mice, associated with altered pulmonary function leading to respiratory failure. These lung abnormalities start early in life, as demonstrated in one-quarter of 2-day-old Muc5b-deficient pups. Thus, the mouse mucin Muc5b is essential for maintaining normal lung function.

Uteroglobin gene polymorphism (G38A) may be a risk factor in childhood idiopathic nephrotic syndrome

BACKGROUND

Uteroglobin (UG) is a multifunctional protein with anti-inflammatory properties. The aim of this study was to first evaluate the role of UG gene G38A polymorphism in childhood idiopathic nephrotic syndrome (INS), and determine whether this variation may be related to the occurrence of INS or a steroid response.

METHODS

One hundred and thirty-six children diagnosed with INS in Gaziantep University, Department of Pediatric Nephrology, and 70 healthy volunteers were included. Children with INS were divided into two groups: steroid-sensitive (n = 84), and steroid-resistant (n = 52). Samples were examined using the polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) enzyme method.

RESULTS

The distributions of AA, GG, and AG genotypes of UG gene G38A (G/A) were 16.9%, 44.9%, and 38.2% in the all-INS group, whereas they were 14.3%, 48.8%, and 36.9% in the steroid-sensitive INS (SSINS) group compared with 21.1%, 38.5%, and 40.4% in steroid-resistant INS (SRINS), and 5.7%, 41.4%, and 52.9% in controls. The risk of INS was increased almost 4-fold in children with the AA genotype (p = 0.016). The risk of having SSINS was increased 3.5-fold (p = 0.042) whereas the risk of SRINS was increased 4.8-fold in the same genotype (p = 0.014).

CONCLUSIONS

The uteroglobin gene may play an important role in the development of INS, and the AA genotype of UG gene G38A polymorphism was found more frequently in those children. Further studies evaluating all polymorphisms in larger patient groups are needed to exactly determine the effect of UG gene on the development of INS and steroid response in children.

Studies of an Androgen-Binding Protein Knockout Corroborate a Role for Salivary ABP in Mouse Communication

The house mouse Androgen-binding protein (Abp) gene family is comprised of 64 paralogs, 30 Abpa and 34 Abpbg, encoding the alpha (ABPA) and beta-gamma (ABPBG) protein subunits that are disulfide-bridged to form dimers in secretions. Only 14 Abp genes are expressed in distinct patterns in the lacrimal (11) and submandibular glands (3). We created a knockout mouse line lacking two of the three genes expressed in submandibular glands, Abpa27 and Abpbg27, by replacing them with the neomycin resistance gene. The knockout genotype (-/-) showed no Abpa27 or Abpbg27 transcripts in submandibular gland complementary DNA (cDNA) libraries and there was a concomitant lack of protein expression of ABPA27 and ABPBG27 in the -/- genotype saliva, shown by elimination of these two proteins from the saliva proteome and the loss of cross-reactive material in the acinar cells of the submandibular glands. We also observed a decrease in BG26 protein in the -/- animals, suggesting monomer instability. Overall, we observed no major phenotypic changes in the -/- genotype, compared with their +/+ and +/- siblings raised in a laboratory setting, including normal growth curves, tissue histology, fecundity, and longevity. The only difference is that male and female C57BL/6 mice preferred saliva of the opposite sex containing ABP statistically significantly more than saliva of the opposite sex without ABP in a Y-maze test. These results show for the first time that mice can sense the presence of ABP between saliva targets with and without ABPs, and that they spend more time investigating the target containing ABP.

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.

Relation between circulating CC16 concentrations, lung function, and development of chronic obstructive pulmonary disease across the lifespan: a prospective study

BACKGROUND

Low concentrations of the anti-inflammatory protein CC16 (approved symbol SCGB1A1) in serum have been associated with accelerated decline in forced expiratory volume in 1 s (FEV1) in patients with chronic obstructive pulmonary disease (COPD). We investigated whether low circulating CC16 concentrations precede lung function deficits and incidence of COPD in the general population.

METHODS

We assessed longitudinal data on CC16 concentrations in serum and associations with decline in FEV1 and incidence of airflow limitation for adults who were free from COPD at baseline in the population-based Tucson Epidemiological Study of Airway Obstructive Disease ([TESAOD] n=960, mean follow-up 14 years), European Community Respiratory Health Survey ([ECRHS-Sp] n=514, 11 years), and Swiss Cohort Study on Air Pollution and Lung Diseases in Adults ([SAPALDIA] n=167, 8 years) studies. Additionally, we measured circulating CC16 concentrations in samples from children aged 4-6 years in the Tucson Children's Respiratory Study (n=427), UK Manchester Asthma and Allergy Study (n=481), and the Swedish Barn/children, Allergy, Milieu, Stockholm, Epidemiological survey (n=231) birth cohorts to assess whether low CC16 concentrations in childhood were predictive for subsequent lung function.

FINDINGS

After adjustment for sex, age, height, smoking status and intensity, pack-years, asthma, and FEV1 at baseline, we found an inverse association between CC16 concentration and decline in FEV1 in adults in TESAOD (4·4 mL/year additional FEV1 decline for each SD decrease in baseline CC16 concentration, p=0·0014) and ECRHS-Sp (2·4 mL/year, p=0·023); the effect in SAPALDIA was marginal (4·5 mL/year, p=0·052). Low CC16 concentration at baseline was also associated with increased risk of incident stage 2 airflow limitation (ratio of FEV1 to forced expiratory volume [FEV1/FVC] less than 70% plus FEV1 % predicted less than 80%) in TESAOD and ECRHS-Sp. In children, the lowest tertile of CC16 concentrations was associated with a subsequent FEV1 deficit of 68 mL up to age 16 years (p=0·0001), which was confirmed in children who had never smoked by age 16 years (-71 mL, p<0·0001).

INTERPRETATION

Low concentrations of CC16 in serum are associated with reduced lung function in childhood, accelerated lung function decline in adulthood, and development of moderate airflow limitation in the general adult population.

FUNDING

National Heart, Lung, and Blood Institute and European Union Seventh Framework Programme.

Protective role for club cell secretory protein-16 (CC16) in the development of COPD

Club cell secretory protein-16 (CC16) is the major secreted product of airway club cells, but its role in the pathogenesis of chronic obstructive pulmonary disease (COPD) is unclear. We measured CC16 airway expression in humans with and without COPD and CC16 function in a cigarette smoke (CS)-induced COPD murine model. Airway CC16 expression was measured in COPD patients, smokers without COPD and non-smokers. We exposed wildtype (WT) and CC16(-/-)mice to CS or air for up to 6 months, and measured airway CC16 expression, pulmonary inflammation, alveolar septal cell apoptosis, airspace enlargement, airway mucin 5AC (MUC5AC) expression, small airway remodelling and pulmonary function. Smokers and COPD patients had reduced airway CC16 immunostaining that decreased with increasing COPD severity. Exposing mice to CS reduced airway CC16 expression. CC16(-/-) mice had greater CS-induced emphysema, airway remodelling, pulmonary inflammation, alveolar cell apoptosis, airway MUC5AC expression, and more compliant lungs than WT mice. These changes were associated with increased nuclear factor-κB (NF-κB) activation in CC16(-/-) lungs. CS-induced acute pulmonary changes were reversed by adenoviral-mediated over-expression of CC16. CC16 protects lungs from CS-induced injury by reducing lung NF-κB activation. CS-induced airway CC16 deficiency increases CS-induced pulmonary inflammation and injury and likely contributes to the pathogenesis of COPD.

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.

Repair of naphthalene-induced acute tracheal injury by basal cells depends on β-catenin

OBJECTIVES

Little is known about the role of Wnt/β-catenin in postnatal airway homeostasis and basal cell function. This study aimed to investigate the role of Wnt signaling in the self-renewal of basal cells and the involvement of β-catenin in tracheal repair after naphthalene-induced injury.

METHODS

Mice were treated with naphthalene and injected with 4-hydroxytamoxifen. Injury and repair of the tracheal epithelium after naphthalene-mediated secretory cell depletion was assessed by a immunohistochemical study. The involvement of Wnt and β-catenin signaling in basal cell proliferation was investigated during in vitro expansion.

RESULTS

Immunohistochemical analysis of tracheal epithelium in wild-type mice showed a reduction in the number of Clara cell secretory protein (CCSP+) and forkhead box transcription factor (Fox-J1+) cells on days 2 to 5 after naphthalene-induced injury; this cell population was regenerated by day 10. After flush labeling, bromodeoxyuridine-positive (BrdU+) cells and Ki67+ cells were observed in tracheal epithelium on days 2 to 5 but not on days 10 and 21. Confocal microscopy visualizing K5+ and BrdU+ cells showed that Wnt3a promotes proliferation of K5+ cells. Immunohistochemical analysis of K5+ and CCSP+ in tracheal epithelial cells from wild-type littermate and K5-Cre-mediated β-catenin knock-out mice showed that on day 3, the number of CCSP+ cells was decreased in all mice. On day 10, CCSP+ cells were present in wild-type littermate mice but absent in conditional knock-out mice.

CONCLUSIONS

Basal cells serve as stem cells in the tracheal epithelium, regenerating and maintaining tracheal epithelial cells in a mouse model of tracheal injury. β-Catenin is required for proliferation and self-renewal of tracheal epithelial cells.

Club cell secretory protein improves survival in a murine obliterative bronchiolitis model

Club cell secretory protein (CCSP) is an indirect phospholipase A2 inhibitor with some immunosuppressive and antiproliferative properties that is expressed in bronchiolar Club cells. In our murine bone marrow transplant (BMT) model of obliterative bronchiolitis (OB), CCSP is diminished; however, its role is unknown. To determine the role of CCSP, B6 wild-type (WT) or CCSP-deficient (CCSP(-/-)) mice were lethally conditioned and given allogeneic bone marrow with a sublethal dose of allogeneic splenic T cells to induce OB. We found that CCSP(-/-) mice demonstrated a higher mortality following BMT-induced OB compared with WT mice. Mice were analyzed 60 days post-BMT for protein expression, pulmonary function, and histology. CCSP levels were reduced in WT mice with BMT-induced OB, and lower levels correlated to decreased lung compliance. CCSP(-/-) had a higher degree of injury and fibrosis as measured by hydroxy proline, along with an increased lung resistance and the inflammatory markers, leukotriene B4 and CXCL1. Replacement with recombinant intravenous CCSP partially reversed the weight loss and improved survival in the CCSP(-/-) mice. In addition, CCSP replacement improved histology and decreased inflammatory cells and markers. These findings indicate that CCSP has a regulatory role in OB and may have potential as a preventive therapy.

Berberine ameliorates renal injury by regulating G proteins-AC- cAMP signaling in diabetic rats with nephropathy

Diabetic nephropathy (DN) is a progressive kidney disease that is caused by injury to glomerulus and glomerular mesangial cells (MCs) proliferation play a critical role in the pathogenesis of DN. The current studies were undertaken to investigate the protective effects and the possible molecular mechanism of berberine on streptozotocin (STZ)-induced DN rats. Male Wistar rats were randomly assigned to normal control and DN groups of comparable age. Three DN groups received 50, 100 and 200 mg/kg of berberine for 8 weeks via daily intragastrically, respectively. The G proteins-adenylyl cyclase (AC)-cAMP signaling pathway and glomerular MCs proliferation were examined in STZ-induced diabetic rat kidney. Enhanced MCs proliferation and remarkable renal injury were concomitant with activation of Gαi and inhibition of Gαs and cAMP in DN model group. Berberine treatment for 8 weeks abolished the above changes by upregulating the expression of Gαs protein and downregulating the expression of Gαi protein, increasing cAMP level, and inhibiting MCs proliferation compared with model group. Taken together, for the first time, these results demonstrated that berberine can relieve renal injury in DN rats through mediating G proteins-AC-cAMP signaling pathway and inhibiting the abnormal proliferation of MCs by increasing cAMP level, suggesting that berberine could be a potential therapeutic agent for the treatment of DN.

Alleviation of lung inflammatory responses by adeno-associated virus 2/9 vector carrying CC10 in OVA-sensitized mice

Asthma is a chronic airway inflammatory disease characterized by eosinophilic infiltration and airway hyperresponsiveness. The over-activated Th2 and lung epithelium cells express many different cytokines, and chemokines mainly contribute to the severity of lung inflammation. Clara cell 10 kD protein (CC10) is highly expressed in airway epithelium cells and exhibits anti-inflammatory and immunomodulatory effects. Adeno-associated virus (AAV) 2/9 vector, composed of AAV2 rep and AAV9 cap genes, can efficiently and specifically target lung epithelium cells. Thus, AAV2/9 vector might carry therapeutic potential gene sequences for the treatment of asthma. This study tested whether AAV2/9 vector carrying CC10 could reduce inflammatory and asthmatic responses in OVA-induced asthmatic mouse model. The results showed that AAV2/9-CC10 vector virus significantly reduced airway hyperresponsiveness, CCL11, interleukin (IL)-4, IL-5, IL-6, IL-13, and eosinophilia in the lungs of sensitized mice. CC10 level in OVA-sensitized mice was rescued with the administration of AAV2/9-CC10 vector virus. Lung tissue remodeling, including collagen deposition and goblet cell hyperplasia, was also alleviated. However, serum levels of OVA-specific IgG1 and IgE as well as Th2 cytokine levels in OVA-stimulated splenocyte culture supernatants were at the comparable levels to the sensitized control group. The results demonstrate that AAV2/9-CC10 vector virus relieved local inflammatory and asthmatic responses in lung. Therefore, we propose that AAV2/9-CC10 vector virus guaranteed sufficient CC10 expression and had an anti-inflammatory effect in asthmatic mice. It might be applied as a novel therapeutic approach for asthma.

Update of the human secretoglobin (SCGB) gene superfamily and an example of 'evolutionary bloom' of androgen-binding protein genes within the mouse Scgb gene superfamily

The secretoglobins (SCGBs) comprise a family of small, secreted proteins found in animals exclusively of mammalian lineage. There are 11 human SCGB genes and five pseudogenes. Interestingly, mice have 68 Scgb genes, four of which are highly orthologous to human SCGB genes; the remainder represent an 'evolutionary bloom' and make up a large gene family represented by only six counterparts in humans. SCGBs are found in high concentrations in many mammalian secretions, including fluids of the lung, lacrimal gland, salivary gland, prostate and uterus. Whereas the biological activities of most individual SCGBs have not been fully characterised, what already has been discovered suggests that this family has an important role in the modulation of inflammation, tissue repair and tumorigenesis. In mice, the large Scgb1b and Scgb2b gene families encode the androgen-binding proteins, which have been shown to play a role in mate selection. Although much has been learned about SCGBs in recent years, clearly more research remains to be done to allow a better understanding of the roles of these proteins in human health and disease. Such information is predicted to reveal valuable novel drug targets for the treatment of inflammation, as well as designing biomarkers that might identify tissue damage or cancer.

Clara cell 10-kDa protein gene transfection inhibits NF-κB activity in airway epithelial cells

BACKGROUND

Clara cell 10-kDa protein (CC10) is a multifunctional protein with anti-inflammatory and immunomodulatory effects. Induction of CC10 expression by gene transfection may possess potential therapeutic effect. Nuclear factor κB (NF-κB) plays a key role in the inflammatory processes of airway diseases.

METHOD/RESULTS

To investigate potential therapeutic effect of CC10 gene transfection in controlling airway inflammation and the underlying intracellular mechanisms, in this study, we constructed CC10 plasmid and transfected it into bronchial epithelial cell line BEAS-2B cells and CC10 knockout mice. In BEAS-2B cells, CC10's effect on interleukin (IL)-1β induced IL-8 expression was explored by means of RT-PCR and ELISA and its effect on NF-κB classical signaling pathway was studied by luciferase reporter, western blot, and immunoprecipitation assay. The effect of endogenous CC10 on IL-1β evoked IL-8 expression was studied by means of nasal explant culture. In mice, CC10's effect on IL-1β induced IL-8 and nuclear p65 expression was examined by immunohistochemistry. First, we found that the CC10 gene transfer could inhibit IL-1β induced IL-8 expression in BEAS-2B cells. Furthermore, we found that CC10 repressed IL-1β induced NF-κB activation by inhibiting the phosphorylation of IκB-α but not IκB kinase-α/β in BEAS-2B cells. Nevertheless, we did not observe a direct interaction between CC10 and p65 subunit in BEAS-2B cells. In nasal explant culture, we found that IL-1β induced IL-8 expression was inversely correlated with CC10 levels in human sinonasal mucosa. In vivo study revealed that CC10 gene transfer could attenuate the increase of IL-8 and nuclear p65 staining in nasal epithelial cells in CC10 knockout mice evoked by IL-1β administration.

CONCLUSION

These results indicate that CC10 gene transfer may inhibit airway inflammation through suppressing the activation of NF-κB, which may provide us a new consideration in the therapy of airway inflammation.

Allergic asthma: influence of genetic and environmental factors

Allergic asthma is a chronic airway inflammatory disease in which exposure to allergens causes intermittent attacks of breathlessness, airway hyper-reactivity, wheezing, and coughing. Allergic asthma has been called a "syndrome" resulting from a complex interplay between genetic and environmental factors. Worldwide, >300 million individuals are affected by this disease, and in the United States alone, it is estimated that >35 million people, mostly children, suffer from asthma. Although animal models, linkage analyses, and genome-wide association studies have identified numerous candidate genes, a solid definition of allergic asthma has not yet emerged; however, such studies have contributed to our understanding of the multiple pathways to this syndrome. In contrast with animal models, in which T-helper 2 (T(H)2) cell response is the dominant feature, in human asthma, an initial exposure to allergen results in T(H)2 cell-dependent stimulation of the immune response that mediates the production of IgE and cytokines. Re-exposure to allergen then activates mast cells, which release mediators such as histamines and leukotrienes that recruit other cells, including T(H)2 cells, which mediate the inflammatory response in the lungs. In this minireview, we discuss the current understanding of how associated genetic and environmental factors increase the complexity of allergic asthma and the challenges allergic asthma poses for the development of novel approaches to effective treatment and prevention.

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.

Clara cell 10-kD protein suppresses chitinase 3-like 1 expression associated with eosinophilic chronic rhinosinusitis

RATIONALE

Clara cell 10-kD (CC10) protein, an antiinflammatory molecule, is involved in inflammatory upper airway diseases, but its regulatory role is unclear, particularly in the process of chronic rhinosinusitis (CRS).

OBJECTIVES

To investigate the regulatory mechanisms of CC10 in eosinophilic CRS (ECRS) using an allergic mouse model.

METHODS

Homozygous CC10-knockout mice were used to establish an allergic ECRS model. Phenotypic changes were examined by histology, cytokine ELISA, and gene microarray analysis. Differential expression of chitinase 3-like 1 (CHI3L1) was verified by quantitative reverse transcriptase-polymerase chain reaction and immunohistochemistry. The functional role of CHI3L1 in vivo was assessed by the use of anti-CHI3L1 antibody in ECRS mice. CHI3L1 gene expression regulated by inflammatory cytokines and CC10 protein was performed using BEAS-2B cell line.

MEASUREMENTS AND MAIN RESULTS

Compared with wild-type mice, a significantly greater extent of inflammatory cell infiltration and tissue remodeling was found in CC10-knockout ECRS mice, which was associated with significantly higher levels of various cytokines and eotaxin-1. CHI3L1 was up-regulated in ECRS mice with a significant further increase in CC10-knockout mice. Anti-CHI3L1 treatment markedly ameliorated eosinophilic inflammation. Furthermore, nasal mucosal CC10 gene transfer in CC10-knockout mice attenuated eosinophilic inflammation and suppressed the levels of CHI3L1. Moreover, significantly up-regulated expression of CHI3L1 was noted in human ECRS. IL-1beta, tumor necrosis factor-alpha, and IL-13 were found to up-regulate CHI3L1 expression in BEAS-2B cells, whereas CC10 inhibited such up-regulation.

CONCLUSIONS

These results suggest that CHI3L1 is a novel molecule involved in ECRS and that CC10 plays a regulatory role in ECRS, presumably by attenuating CHI3L1 expression.

Airway regeneration: the role of the Clara cell secretory protein and the cells that express it

Clara cell secretory protein (CCSP) is one of the most abundant proteins in the airway surface fluid, and has many putative functions. Recent advances in the field of stem cells and lung regeneration have identified potentially new roles of CCSP and CCSP-expressing cell populations in airway maintenance, repair and regeneration. This review focuses on the airway regenerative potential of CCSP and the cells that express this protein. The use of this protein or CCSP-expressing cells as an indication of biologic processes that contribute to lung injury or repair is highlighted.

Clara cells attenuate the inflammatory response through regulation of macrophage behavior

Chronic lung diseases are marked by excessive inflammation and epithelial remodeling. Reduced Clara cell secretory function and corresponding decreases in the abundance of the major Clara cell secretory protein (CCSP) are characteristically seen in these disease states. We sought to define the impact of Clara cell and CCSP depletion on regulation of the lung inflammatory response. We used chemical and genetic mouse models of Clara cell and CCSP deficiency (CCSP(-/-)) coupled with Pseudomonas aeruginosa LPS elicited inflammation. Exposure of Clara cell-depleted or CCSP(-/-) mice to LPS resulted in augmented inflammation as assessed by polymorphonuclear leukocyte recruitment to the airspace. Gene expression analysis and pathway modeling of the CCSP(-/-) inflammatory response implicated increased TNF-alpha signaling. Consistent with this model was the demonstration of significantly elevated TNF-alpha in airway fluid of LPS-stimulated CCSP(-/-) mice compared with similarly exposed wild-type mice. Increased LPS-elicited TNF-alpha production was also observed in cultured lung macrophages from CCSP(-/-) mice compared with wild-type mice. We demonstrate that macrophages from Clara cell-depleted and CCSP(-/-) mice displayed increased Toll-like receptor 4 surface expression. Our results provide evidence that Clara cells can attenuate inflammation through regulation of macrophage behavior, and suggest that epithelial remodeling leading to reduced Clara cell secretory function is an important factor that increases the intensity of lung inflammation in chronic lung disease.

Endogenous lung stem cells and contribution to disease

Epithelial branching during the process of lung development results in the establishment of distinct functional zones, each of which is characterized by a unique cellular composition and repertoire of local progenitor cells. Significant new insights into cellular and molecular mechanisms of epithelial maintenance that provide insights into the pathophysiology of lung disease have been made in recent years. This review focuses on the complex structure-function relationship in the airway epithelium, how this epithelium is maintained in the normal state and repaired following injury, and how deregulation may contribute to airway disease and cancer.

Cord blood Clara cell protein CC16 predicts the development of bronchopulmonary dysplasia

Clara cell protein (CC16) is an anti-inflammatory protein and a biomarker of pulmonary epithelial cells and alveolocapillary membrane injury in adults. We investigated whether low cord blood concentrations of CC16 are associated with the development of respiratory distress syndrome (RDS) and bronchopulmonary dysplasia (BPD) in preterm infants and the relationship between CC16 and its pro-inflammatory counterpart, the secretory phospholipase A(2) (sPLA(2)) enzyme. CC16 concentration, sPLA(2) activity and IL-6 concentration were measured in cord blood plasma from 79 preterm infants (25 controls, 37 infants who developed RDS and 17 infants who developed BPD). After adjustment for gestational age and Apgar score at 5 min, the CC16 concentration was lower in BPD infants than in preterm controls (p<0.01). sPLA(2) activity was similar in all groups and the IL-6 concentrations were increased in both RDS and BPD infants (p<0.01 and p<0.05, respectively, vs. controls). We conclude that low cord blood CC16 concentrations in preterm infants independently predict the development of BPD. Low CC16 levels may reflect early lung injury, which contributes to the severity of RDS and progress towards BPD. Future studies are needed to assess whether the early administration of recombinant human CC16 in preterm infants with low cord blood CC16 prevents the development of BPD.

Role of secretoglobin 3A2 in lung development

RATIONALE

Secretoglobin 3A2 (SCGB3A2) was originally identified as a downstream target in lung for the homeodomain transcription factor NKX2-1, whose null mutation resulted in severely hypoplastic lungs. A very low level of SCGB3A2 is expressed in lungs at Embryonic Day (E) 11.5 during mouse development, which markedly increases by E16.5, the time when lung undergoes dramatic morphologic changes, suggesting that SCGB3A2 may be involved in lung development in addition to a known role in lung inflammation.

OBJECTIVES

To determine whether SCGB3A2 plays a role in lung development.

METHODS

To assess a potential role for SCGB3A2 during early lung development, wild-type and Nkx2-1-null fetal lungs of early developmental stages were subjected to ex vivo organ culture in the presence of SCGB3A2. Nkx2-1-null fetuses were exposed to SCGB3A2 during early organogenesis period through intravenous administration of this protein to Nkx2-1-heterozygous pregnant females carrying these null fetuses. Cultured lungs and fetal lungs were subjected to histologic and immunohistochemical analyses. To assess a role for SCGB3A2 in late lung development, SCGB3A2 was administered to pregnant wild-type females during mid- to late organogenesis stages, and the preterm pups and/or their lungs were evaluated for extent of maturity using breathing motion, gross morphology and histology of lungs, expression of gestational stage-specific genes, and phospholipid profiles.

MEASUREMENTS AND MAIN RESULTS

SCGB3A2 significantly promoted both early and late stages of lung development.

CONCLUSIONS

SCGB3A2 is a novel growth factor in lung.

Uteroglobin interacts with the heparin-binding site of fibronectin and prevents fibronectin-IgA complex formation found in IgA-nephropathy

Immunoglobulin A (IgA)-nephropathy (IgAN) is the most common primary renal glomerular disease in the world that has no effective treatment. High levels of circulating IgA-fibronectin (Fn) complexes, characteristically found in IgAN patients, are suggested to cause abnormal deposition of IgA and Fn in the renal glomeruli of these patients causing renal failure. We previously reported that binding of Fn to uteroglobin (UG), a multifunctional anti-inflammatory protein, inhibits Fn-IgA heteromerization. However, the specific site of Fn-UG interaction until now remained unidentified. We report here that UG interacts with the heparin-binding site of Fn and propose that small molecules competing for interaction with this site may reduce the level of circulating Fn-IgA complexes in IgAN.

Mutations in FN1 cause glomerulopathy with fibronectin deposits

Glomerulopathy with fibronectin (FN) deposits (GFND) is an autosomal dominant disease with age-related penetrance, characterized by proteinuria, microscopic hematuria, hypertension, and massive glomerular deposits of FN that lead to end-stage renal failure. The genetic abnormality underlying GFND was still unknown. We hypothesized that mutations in FN1, which encodes FN, were the cause of GFND. In a large Italian pedigree with eight affected subjects, we found linkage with GFND at the FN1 locus at 2q32. We sequenced the FN1 in 15 unrelated pedigrees and found three heterozygous missense mutations, the W1925R, L1974R, and Y973C, that cosegregated with the disease in six pedigrees. The mutations affected two domains of FN (Hep-II domain for the W1925R and the L1974R, and Hep-III domain for the Y973C) that play key roles in FN-cell interaction and in FN fibrillogenesis. Mutant recombinant Hep-II fragments were expressed, and functional studies revealed a lower binding to heparin and to endothelial cells and podocytes compared with wild-type Hep-II and an impaired capability to induce endothelial cell spreading and cytoskeletal reorganization. Overall dominant mutations in FN1 accounted for 40% of cases of GFND in our study group. These findings may help understanding the pathogenesis of proteinuria and glomerular FN deposits in GFND and possibly in more common renal diseases such as diabetic nephropathy, IgA nephropathy, and lupus nephritis. To our knowledge no FN1 mutation causing a human disease was previously reported.

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.

CC10 reduces inflammation in meconium aspiration syndrome in newborn piglets

Complications from meconium aspiration syndrome (MAS) remain significant despite a variety of therapeutic interventions. Clara cell protein (CC10) is a novel anti-inflammatory agent that can also inhibit phospholipase A2 (PLA2) (an important component of meconium). The present study examined whether administration of recombinant human CC10 (rhCC10) would reduce inflammation and improve lung function in a piglet model of MAS. Following meconium instillation, piglets exhibited significant physiologic dysfunction that improved significantly after surfactant administration. Analysis of tracheal aspirates revealed significant increases in both tumor necrosis factor (TNF) alpha and interleukin (IL)-8 after meconium instillation. rhCC10-treated animals had significantly lower TNF-alpha levels at 24 h (561 +/- 321 versus 1357 +/- 675 pg/mL, p < 0.05) compared with saline controls. There were no differences between rhCC10-treated and untreated groups with respect to other measured physiologic variables or inflammatory markers, including secretory PLA2 activity. Histologic analyses revealed marked inflammatory infiltrates and thickened alveolar walls, but no significant differences among rhCC10 and control animals. Newborn piglets with MAS have significant physiologic dysfunction, marked inflammatory changes and histologic abnormalities, which was partially counteracted by a single dose of exogenous surfactant and rhCC10.

Pathology of glomerular deposition diseases

In routine diagnosis on renal biopsy, one of the confusing fields for pathological diagnoses is the glomerulopathies with fibrillary structure. The primary glomerulopathies with a deposit of ultrastructural fibrillary structure, which are negative for Congo-red stain but positive for immunoglobulins, include fibrillary glomerulonephritis and immunotactoid glomerulopathy. Several paraproteinemias including cryoglobulinemia, monoclonal gammopathy, and light chain deposition disease as well as hematopoietic disorders including plasmacytoma, plasma cell dyscrasia, and B cell lymphoproliferative disorders involve glomerulopathy with an ultrastructural fibrillary structure. A rare glomerulopathy with fibrillary structure that stains negative for Congo-red as well as for immunoglobulins has been also reported. The pathological diagnoses of these glomerulopathies can include either glomerular diseases, or paraproteinemic diseases, or hematopoietic diseases. The terminology is still confusing when glomerular diseases can be combined with paraproteinemic diseases and/or hematopoietic diseases. Therefore, the generic term, 'glomerular deposition disease' (GDD), has been proposed by pathologists with a requirement for clinicians to detect autoantibodies, paraproteins as well as to carry out a bone marrow check. An attempt has been made to rearrange the diseases with related disorders of fibrillary deposits, based on detailed clinical and pathological finding and to elucidate the correlation between GDD, paraproteinemia, and hematopoietic disorder.

Uteroglobin suppresses allergen-induced TH2 differentiation by down-regulating the expression of serum amyloid A and SOCS-3 genes

Allergen-induced airway inflammation may lead to allergic asthma, a chronic inflammatory disease of the respiratory system. Despite its high incidence, the majority of the world's population is unaffected by allergic airway inflammation most likely due to innate protective mechanism(s) in the respiratory system. The mammalian airway epithelia constitutively express uteroglobin (UG), a protein with potent anti-inflammatory and anti-chemotactic properties. We report here that UG binds to FPR2, a G-protein coupled receptor, inhibits chemotaxis, down-regulates SOCS-3 gene expression and STAT-1 activation, which are critical for the differentiation of T-helper 2 (T(H)2) cells that secrete pro-inflammatory T(H)2 cytokines. We propose that UG suppresses allergen-mediated activation of T(H)2 response by down-regulating the expression of genes that are critical for T(H)2 differentiation.

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.

Association of Uteroglobin G38A Polymorphism With IgA Nephropathy: A Meta-Analysis

Both uteroglobin knockout and antisense transgenic mice develop pathological and clinical features similar to immunoglobulin A (IgA) nephropathy. However, several association studies of uteroglobin G38A polymorphism and IgA nephropathy showed controversial findings. We used meta-analysis to assess the impact of the uteroglobin G38A polymorphism on susceptibility to and progression of IgA nephropathy. Six studies involving uteroglobin G38A genotyping of 930 patients with IgA nephropathy and 768 healthy controls were included. No significant publication bias was found (Egger's linear regression, P = 0.763; 95% confidence interval [CI], -0.610 to 0.476). All control samples were in Hardy-Weinberg proportion. No association between the AA genotype and risk for IgA nephropathy relative to both other genotypes (odds ratio [OR], 1.05; 95% CI, 0.71 to 1.54) or A allele and risk for IgA nephropathy (OR, 0.96; 95% CI, 0.84 to 1.11) were shown in the total meta-analysis. In both Asian and European subgroups, the overall effect of the AA genotype and A allele also showed no significant difference. There also was no significant association between uteroglobin AA genotype or A allele and IgA nephropathy progression (OR, 3.62; 95% CI, 0.59 to 22.34; OR, 2.19, 95% CI, 0.37 to 13.14, respectively). We suggest that uteroglobin G38A polymorphism is not related to the development and progression of IgA nephropathy.

Recombinant human uteroglobin/CC10 inhibits the adhesion and migration of primary human endothelial cells via specific and saturable binding to fibronectin

Uteroglobin (UG) or Clara Cell 10 kDa protein (CC10) is a small, stable, epithelial secretory anti-inflammatory protein. Uteroglobin has been shown to inhibit neointimal formation in vivo after balloon angioplasty through an unknown mechanism. An interaction between UG and plasma fibronectin (Fn) has been demonstrated in mice. Since Fn plays a key role in endothelial cell (EC) migration and angiogenesis, we investigated whether recombinant human UG (rhUG) affects EC migration via Fn binding. In this report, we show a saturable binding of rhUG to Fn depending on Fn conformation and that rhUG is covalently cross-linked to Fn by transglutaminase (TGase). Additionally, our study highlights that rhUG can also bind to exogenously added or self-secreted Fn on the membrane of human primary microvascular endothelial cells (HMVEC), although these complexes are weakly associated with the plasmalemma. Upon the interaction with Fn in solid phase, rhUG strongly inhibits HMVEC attachment on Fn, but not on other ECM proteins. Consequently, rhUG also inhibits cell migration in a dose dependent fashion (I.C.50 = 65 nM) and hinders the "wound healing" in vitro. The small size, stability and human tolerability of rhUG suggest that rhUG in slow-release form or genetically delivered could be used in humans to modulate cell/Fn interactions in the context of tumor microenvironment or in the context of inflammation and fibrosis.

l7Rn6 encodes a novel protein required for clara cell function in mouse lung development

The highly secretory Clara cells play a pivotal role in protecting the lung against inflammation and oxidative stress. This study reports the positional cloning of a novel protein required for Clara cell physiology in mouse lung development. The perinatal lethal N-ethyl-N-nitrosourea-induced l7Rn6(4234SB) allele contained a nonsense mutation in the previously hypothetical gene NM_026304 on chromosome 7. Whereas l7Rn6 mRNA levels were indistinguishable from wild type, l7Rn6(4234SB) homozygotes exhibited decreased expression of the truncated protein, suggesting protein instability. During late gestation, l7Rn6 was widely expressed in the cytoplasm of lung epithelial cells, whereas perinatal expression was restricted to the bronchiolar epithelium. Homozygosity for the l7Rn6(4234SB) allele did not affect early steps in lung patterning, growth, or cellular differentiation. Rather, mutant lungs demonstrated severe emphysematous enlargement of the distal respiratory sacs at birth. Clara cell pathophysiology was evident from decreased cytoplasmic CCSP and SP-B protein levels, enlargement and disorganization of the Golgi complex, and formation of aberrant vesicular structures. Additional support for a role in the secretory pathway derived from l7Rn6 localization to the endoplasmic reticulum. Thus, l7Rn6 represents a novel protein required for organization and/or function of the secretory apparatus in Clara cells in mouse lung.

Uteroglobin suppresses SCCA gene expression associated with allergic asthma

Uteroglobin (UG), the founding member of the Secretoglobin superfamily, is a potent anti-inflammatory protein constitutively expressed at a high level in the airway epithelia of all mammals. We previously reported that the lungs of UG-knock-out (UG-KO) mice express elevated levels of Th2 cytokines (e.g. interleukin (IL)-4 and IL-13), which are augmented by allergen sensitization and challenge leading to exaggerated airway inflammation. Notably, these responses are suppressed by recombinant UG treatment (Mandal, A. K., Zhang, Z., Ray, R., Choi, M. S., Chowdhury, B., Pattabiraman, N., and Mukherjee, A. B. (2004) J. Exp. Med. 199, 1317-1330). Recent reports indicate that human orthologs of murine squamous cell carcinoma antigen-2 (SCCA-2/serpinb3a), a serine protease-inhibitor, are overexpressed in the airways of asthmatic patients. We report here that compared with wild type littermates, UG-KO mouse lungs express markedly elevated levels of SCCA-2 mRNA and protein, which are augmented by allergen-challenge. Most importantly, these effects are abrogated by recombinant UG treatment. We further demonstrate that treatment of cultured human bronchial epithelial cells with IL-4 or IL-13 stimulates phosphorylation of STAT-1 and STAT-6 leading to SCCA-1 (SERPINB3) and SCCA-2 (SERPINB4) gene expression. We propose that: (i) IL-4- and IL-13-stimulated SCCA gene expression is mediated via STAT-1 and STAT-6 activation, and (ii) by suppressing the production, and most likely by interfering with the signaling of these cytokines, UG inhibits SCCA gene expression associated with airway inflammation in asthma.

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.

Recombinant uteroglobin prevents the experimental crescentic glomerulonephritis

BACKGROUND

Although uteroglobin is known to have an immunomodulatory property and prevents the deposition of immune-complexes on the glomeruli of mice, the therapeutic potential of uteroglobin is uncertain in glomerulonephritis. To test the hypothesis that uteroglobin can prevent glomerulonephritis, we have studied the effects of recombinant uteroglobin on the development of experimental crescentic glomerulonephritis that is induced by anti-glomerular basement membrane (anti-GBM) antibodies.

METHODS AND RESULTS

Glomerulonephritis was induced by the intravenous injection of rabbit anti-GBM globulin antibodies into mice (C57BL/6), and renal injury was evaluated 7, 14, and 21 days afterward. Recombinant uteroglobin or phosphate-buffered saline (PBS) were given intravenously to mice for 3 days after anti-GBM antibody injection. Proteinuria was significantly reduced in mice treated with recombinant uteroglobin compared with disease-control mice at 7 and 14 days after an anti-GBM antibody injection, although the serum creatinine concentration was similar in both groups. The amount of proteinuria was similar in recombinant uteroglobin-treated and normal control mice. By histologic analysis, mesangial matrix expansion, mesangial proliferation, and cellular crescents representing crescentic glomerulonephritis were markedly attenuated by injection of recombinant uteroglobin. The in vitro proliferative responses of mesangial cells to lipopolysaccharide (LPS) were blunted by the addition of recombinant uteroglobin in a dose-dependent manner. The preventive effects exerted by recombinant uteroglobin treatment were based on the inhibition of antibodies and complement-3 deposition on the glomeruli.

CONCLUSION

This study demonstrates the preventive effects of recombinant uteroglobin in an experimental model of crescentic glomerulonephritis, and suggests the therapeutic implications of uteroglobin for human chronic glomerulonephritis.

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.

cDNA sequence, 5′-flanking region, and promoter activity of the Neotomodon alstoni alstoni Clara cell secretory protein gene

To better understand the phylogenetic divergence and the species-specific characteristics of the Clara cell secretory protein (CCSP), we cloned the cDNA encoding the neotomodon CCSP (nCCSP) and analyzed its tissue-specific expression. The full-length cDNA is 451bp long and predicts an amino acid sequence of 93 residues. Northern blot analysis from different neotomodon tissues demonstrated that the mRNA of CCSP appears to be solely expressed in the lung. To study the transcriptional regulation of the CCSP gene, we cloned the 5'-flanking region of the nCCSP gene and compared its features with those previously reported for the hamster gene. The neotomodon and hamster genes share 89% sequence homology in their promoter region as well as a number of conserved cis-acting elements. However, in H441 cells the expression of a reporter gene driven by the nCCSP promoter was about 4-fold greater than its hamster counterpart. Functional analysis of progressive 5'-deletion mutants identified a region involved in the higher transcriptional activity of the neotomodon promoter.

Uteroglobin: a potential novel tumor suppressor and molecular therapeutic for prostate cancer

Currently, there are very few diagnostic or therapeutic strategies targeted at controlling tumor growth and progression towards metastasis. Uteroglobin (UG) is a naturally occurring, small, stable, secretory protein that is normally expressed by most cells of epithelial origin but is known to be lost during the progression of prostate, lung, and uterine cancers to invasive malignancy. Uteroglobin -/- knockout mice appear to be extremely cancer prone. Both pharmacological and transgenic reconstitution of recombinant human UG (rhUG) to prostate, lung, and endometrial tumor cell lines markedly inhibits their invasiveness and antagonizes the neoplastic phenotype. In preliminary studies, rhUG inhibited angiogenesis in the ex vivo rat aorta model and showed antitumor activity against human prostate tumor cells (PC-3) in the chick chorioallantoic membrane assay, reducing both tumor volume and vascularity. A recent in vivo pilot study showed that twice daily dosing with rhUG resulted in a statistically significant increase in survival without evidence of toxicity in severe combined immunodeficient mice challenged with a PC-3 cell metastasizing tumor. Thus, rhUG may slow the progression of cancer by inhibiting both tumor cell invasiveness and tumor angiogenesis. It therefore holds the potential to serve as a new weapon in the arsenal of cytostatic, antimetastatic, adjuvant treatment for cancer. In this paper, we will briefly discuss the therapeutic potential of uteroglobin-based strategies for managing prostate cancer.

Identification of uteroglobin-related protein 1 and macrophage scavenger receptor with collagenous structure as a lung-specific ligand-receptor pair

High in normal (HIN)-1 is a secreted protein highly expressed in normal breast epithelium and down-regulated in breast carcinomas. By searching GenBank expressed sequence tag databases, we identified HIN-2, a protein homologous to HIN-1. HIN-2 is identical with a recently identified protein called uteroglobin-related protein 1 (UGRP1). Northern blot analysis demonstrated that UGRP1 is specifically expressed by lung, but not by the other tissues examined. By in situ hybridization experiments, UGRP1 was shown to be expressed by lung Clara-like cells in the bronchial epithelium and to be up-regulated in cystic fibrosis. In a mammalian expression system, secreted recombinant UGRP1 was copurified with apolipoprotein A-I. Using a retroviral vector-mediated expression cloning approach, we identified macrophage scavenger receptor with collagenous structure (MARCO) as a receptor for UGRP1. Northern blot and in situ hybridization experiments indicated that MARCO is expressed by alveolar macrophages in the lung. UGRP1 also bound to bacteria and yeast. LPS, a previously identified MARCO ligand, competed with UGRP1 for binding to MARCO and bacteria. Our findings suggest that UGRP1-MARCO is a ligand-receptor pair that is probably involved in inflammation and pathogen clearance in the lung.

Dysregulated secretoglobin expression in human lung cancers

Lipophilins A, B, C, mammaglobin, and uteroglobin are members of the secretoglobin family of small, secreted, proteins. The functions of these proteins are not well understood but uteroglobin has been implicated in the development of cancers. Uteroglobin is known to be highly expressed in normal lung and down-regulated in lung cancers but expression of the other secretoglobins in normal lung and lung neoplasms have not been investigated. Therefore, we developed quantitative real-time reverse transcription (RT-) PCR assays for the different secretoglobins and evaluated their expression in normal and neoplastic lung tissues. The secretoglobin transcript levels were quantitated by real-time RT-PCR in samples from three normal lungs, 24 lung tumors including six small cell lung carcinomas, seven adenocarcinomas, and five squamous cell carcinomas, and in cell lines from three small cell lung carcinomas and one mesothelioma. Uteroglobin was confirmed to be abundantly expressed in normal lung and the different lung tumors showed down-regulated uteroglobin expression. Of the other secretoglobins, only lipophilin C was detected in normal lung, albeit at low levels. The lung tumors, however, frequently showed neo- or up-regulation of lipophilins A, B, C, and mammaglobin. The results constitute the first quantitative evaluation of secretoglobin expression in normal and neoplastic human lung tissues and demonstrate dysregulation in various human lung cancers. These findings could have important biological and diagnostic implications.