Increased coexpression of CFTR and S100 calcium binding proteins MRP8 and MRP14 mRNAs in cystic fibrosis human tracheal gland cells

S100 family proteins in inflammation and beyond

The S100 family proteins possess a variety of intracellular and extracellular functions. They interact with multiple receptors and signal transducers to regulate pathways that govern inflammation, cell differentiation, proliferation, energy metabolism, apoptosis, calcium homeostasis, cell cytoskeleton and microbial resistance. S100 proteins are also emerging as novel diagnostic markers for identifying and monitoring various diseases. Strategies aimed at targeting S100-mediated signaling pathways hold a great potential in developing novel therapeutics for multiple diseases. In this chapter, we aim to summarize the current knowledge about the role of S100 family proteins in health and disease with a major focus on their role in inflammatory conditions.

A subset of calcium-binding S100 proteins show preferential heterodimerization

The assembly of proteins into dimers and oligomers is a necessary step for the proper function of transcription factors, muscle proteins, and proteases. In uncontrolled states, oligomerization can also contribute to illnesses such as Alzheimer's disease. The S100 protein family is a group of dimeric proteins that have important roles in enzyme regulation, cell membrane repair, and cell growth. Most S100 proteins have been examined in their homodimeric state, yet some of these important proteins are found in similar tissues implying that heterodimeric molecules can also be formed from the combination of two different S100 members. In this work, we have established co-expression methods in order to identify and quantify the distribution of homo- and heterodimers for four specific pairs of S100 proteins in their calcium-free states. The split GFP trap methodology was used in combination with other GFP variants to simultaneously quantify homo- and heterodimeric S100 proteins in vitro and in living cells. For the specific S100 proteins examined, NMR, mass spectrometry, and GFP trap experiments consistently show that S100A1:S100B, S100A1:S100P, and S100A11:S100B heterodimers are the predominant species formed compared to their corresponding homodimers. We expect the tools developed here will help establish the roles of S100 heterodimeric proteins and identify how heterodimerization might alter the specificity for S100 protein action in cells.

The role of calprotectin in pediatric disease

Calprotectin (CP) is a calcium- and zinc-binding protein of the S100 family expressed mainly by neutrophils with important extracellular activity. The aim of the current review is to summarize the latest findings concerning the role of CP in a diverse range of inflammatory and noninflammatory conditions among children. Increasing evidence suggests the implication of CP in the diagnosis, followup, assessment of relapses, and response to treatment in pediatric pathological conditions, such as inflammatory bowel disease, necrotizing enterocolitis, celiac disease, intestinal cystic fibrosis, acute appendicitis, juvenile idiopathic arthritis, Kawasaki disease, polymyositis-dermatomyositis, glomerulonephritis, IgA nephropathy, malaria, HIV infection, hyperzincemia and hypercalprotectinemia, and cancer. Further studies are required to provide insights into the actual role of CP in these pathological processes in pediatrics.

Update of faecal markers of inflammation in children with cystic fibrosis

There is evidence of intestinal inflammation in patients with CF. Intestinal inflammation may negatively impact the nutritional status of patient with CF, which adversely affects pulmonary function and survival. This paper provides an up-to-date review of intestinal inflammation in CF and an evaluation of utility of two specific faecal inflammatory markers (S100A12 and calprotectin).

Role of S100A12 in the pathogenesis of osteoarthritis

S100A12 is a member of the S100 protein family, which are intracellular calcium-binding proteins. Although there are many reports on the involvement of S100A12 in inflammatory diseases, its presence in osteoarthritic cartilage has not been reported. The purpose of this study was to investigate the expression of S100A12 in human articular cartilage in osteoarthritis (OA) and to evaluate the role of S100A12 in human OA chondrocytes. We analyzed S100A12 expression by immunohistochemical staining of cartilage samples obtained from OA and non-OA patients. In addition, chondrocytes were isolated from knee cartilage of OA patients and treated with recombinant human S100A12. Real-time RT-PCR was performed to analyze mRNA expression. Protein production of matrix metalloproteinase 13 (MMP-13) and vascular endothelial growth factor (VEGF) in the culture medium were measured by ELISA. Immunohistochemical analyses revealed that S100A12 expression was markedly increased in OA cartilages. Protein production and mRNA expression of MMP-13 and VEGF in cultured OA chondrocytes were significantly increased by treatment with exogenous S100A12. These increases in mRNA expression and protein production were suppressed by administration of soluble receptor for advanced glycation end products (RAGE). Both p38 mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) inhibitors also suppressed the increases in mRNA expression and protein production of MMP-13 and VEGF. We demonstrated marked up-regulation of S100A12 expression in human OA cartilages. Exogenous S100A12 increased the production of MMP-13 and VEGF in human OA chondrocytes. Our data indicate the possible involvement of S100A12 in the development of OA by up-regulating MMP-13 and VEGF via p38 MAPK and NF-κB pathways.

A genome-wide analysis of open chromatin in human tracheal epithelial cells reveals novel candidate regulatory elements for lung function

BACKGROUND

Distal cell-type-specific regulatory elements may be located at very large distances from the genes that they control and are often hidden within intergenic regions or in introns of other genes. The development of methods that enable mapping of regions of open chromatin genome wide has greatly advanced the identification and characterisation of these elements.

METHODS

Here we use DNase I hypersensitivity mapping followed by deep sequencing (DNase-seq) to generate a map of open chromatin in primary human tracheal epithelial (HTE) cells and use bioinformatic approaches to characterise the distribution of these sites within the genome and with respect to gene promoters, intronic and intergenic regions.

RESULTS

Genes with HTE-selective open chromatin at their promoters were associated with multiple pathways of epithelial function and differentiation. The data predict novel cell-type-specific regulatory elements for genes involved in HTE cell function, such as structural proteins and ion channels, and the transcription factors that may interact with them to control gene expression. Moreover, the map of open chromatin can identify the location of potentially critical regulatory elements in genome-wide association studies (GWAS) in which the strongest association is with single nucleotide polymorphisms in non-coding regions of the genome. We demonstrate its relevance to a recent GWAS that identifies modifiers of cystic fibrosis lung disease severity.

CONCLUSION

Since HTE cells have many functional similarities with bronchial epithelial cells and other differentiated cells in the respiratory epithelium, these data are of direct relevance to elucidating the molecular basis of normal lung function and lung disease.

S100A8 modulates mast cell function and suppresses eosinophil migration in acute asthma

S100A8 is implicated in the pathogenesis of inflammatory diseases. S100A8 is upregulated in macrophages by Toll-like receptors (TLR)-3, 4, and 9 agonists in an IL-10-dependent manner, and by corticosteroids in vitro and in vivo, and scavenges oxidants generated by activated phagocytes. Because if its elevated expression in various lung disorders, we asked whether S100A8 was protective in allergic inflammation. S100A8, but not Cys(41)-Ala S100A8, in which the single reactive Cys residue was replaced by Ala, reduced mast cell (MC) degranulation and production of particular cytokines (IL-6, IL-4, and granulocyte macrophage colony-stimulating factor) in response to IgE-crosslinking in vitro, likely by inhibiting intracellular reactive oxygen species production, thereby reducing downstream linker for activation of T cells and extracellular signal regulated kinase/mitogen-activated protein kinase phosphorylation. In lungs of mice with acute asthma, S100A8, but not Cys(41)-Ala S100A8, reduced MC degranulation, production of eosinophil chemoattractants (IL-5, eotaxin, and monocyte chemoattractant protein-1), and eosinophil infiltration. Suppression of IL-6 and IL-13 could have contributed to reduced mucus production seen in lungs of S100A8-treated mice. IgE production was unaffected. In asthma, there is an imbalance of anti-oxidant systems that are generally protective. Our results strongly support a protective role for S100A8 in allergic inflammation by modulating MC activation and eosinophil recruitment, and by scavenging oxidants generated by activated leukocytes, in processes reliant on its thiol-scavenging capacity.

Serum levels of soluble receptor for advanced glycation end products and of S100 proteins are associated with inflammatory, autoantibody, and classical risk markers of joint and vascular damage in rheumatoid arthritis

INTRODUCTION

The receptor for advanced glycation end products (RAGE) is a member of the immunoglobulin superfamily of cell surface receptor molecules. High concentrations of three of its putative proinflammatory ligands, S100A8/A9 complex (calprotectin), S100A8, and S100A12, are found in rheumatoid arthritis (RA) serum and synovial fluid. In contrast, soluble RAGE (sRAGE) may prevent proinflammatory effects by acting as a decoy. This study evaluated the serum levels of S100A9, S100A8, S100A12 and sRAGE in RA patients, to determine their relationship to inflammation and joint and vascular damage.

METHODS

Serum sRAGE, S100A9, S100A8 and S100A12 levels from 138 patients with established RA and 44 healthy controls were measured by ELISA and compared by unpaired t test. In RA patients, associations with disease activity and severity variables were analyzed by simple and multiple linear regressions.

RESULTS

Serum S100A9, S100A8 and S100A12 levels were correlated in RA patients. S100A9 levels were associated with body mass index (BMI), and with serum levels of S100A8 and S100A12. S100A8 levels were associated with serum levels of S100A9, presence of anti-citrullinated peptide antibodies (ACPA), and rheumatoid factor (RF). S100A12 levels were associated with presence of ACPA, history of diabetes, and serum S100A9 levels. sRAGE levels were negatively associated with serum levels of C-reactive protein (CRP) and high-density lipoprotein (HDL), history of vasculitis, and the presence of the RAGE 82Ser polymorphism.

CONCLUSIONS

sRAGE and S100 proteins were associated not just with RA inflammation and autoantibody production, but also with classical vascular risk factors for end-organ damage. Consistent with its role as a RAGE decoy molecule, sRAGE had the opposite effects to S100 proteins in that S100 proteins were associated with autoantibodies and vascular risk, whereas sRAGE was associated with protection against joint and vascular damage. These data suggest that RAGE activity influences co-development of joint and vascular disease in rheumatoid arthritis patients.

IL-10-dependent S100A8 gene induction in monocytes/macrophages by double-stranded RNA

The S100 calcium-binding proteins S100A8 and S100A9 are elevated systemically in patients with viral infections. The S100A8-S100A9 complex facilitated viral replication in human CD4(+) T lymphocytes latently infected with HIV-1- and S100A8-induced HIV-1 transcriptional activity. Mechanisms inducing the S100 genes and the potential source of these proteins following viral activation are unknown. In this study, we show that S100A8 was induced in murine macrophages, and S100A8 and S100A9 in human monocytes and macrophages, by polyinosinic:polycytidylic acid, a dsRNA mimetic. Induction was at the transcriptional level and was IL-10 dependent. Similar to LPS-induced S100A8, induction by dsRNA was dependent on p38 and ERK MAPK. Protein kinase R (PKR) mediates antiviral defense and participates in MyD88-dependent/independent signaling triggered by TLR4 or TLR3. Like IL-10, S100 induction by polyinosinic:polycytidylic acid and by LPS was inhibited by the specific PKR inhibitor 2-aminopurine, indicating a novel IL-10, PKR-dependent pathway. Other mediators such as IFN-beta, which synergized with dsRNA, may also be involved. C/EBPbeta bound the defined promoter region in response to dsRNA. S100A8 was expressed in lungs of mice infected with influenza virus and was maximal at day 8 with strong immunoreactivity in epithelial cells lining the airways and in mononuclear cells and declined early in the recovery phase, implying down-regulation by mediator(s) up-regulated during resolution of the infection. IL-10 is implicated in viral persistence. Since S100A8/S100A9 levels are likely to be maintained in conditions where IL-10 is raised, these proteins may contribute to viral persistence in patients infected by some RNA viruses.

Novel neutrophil-derived proteins in bronchoalveolar lavage fluid indicate an exaggerated inflammatory response in pediatric cystic fibrosis patients

BACKGROUND

Airway inflammation in cystic fibrosis (CF) is exaggerated and characterized by neutrophil-mediated tissue destruction, but its genesis and mechanisms remain poorly understood. To further define the pulmonary inflammatory response, we conducted a proteome-based screen of bronchoalveolar lavage fluid (BALF) collected from young children with and without CF experiencing endobronchial infection.

METHODS

We collected BALF samples from 45 children younger than 5 years and grouped them according to the presence of respiratory pathogens: > or = 1 x 10(5) colony-forming units (CFU)/mL BALF (18 and 12 samples with and without CF, respectively) and <1 x 10(5) CFU/mL (23 and 15 samples). BALF proteins were analyzed with SELDI-TOF mass spectrometry (MS) and H4 ProteinChips. Proteins were identified and characterized using trypsin digestion, tandem MS, Fourier transform ion cyclotron resonance MS, immunoblotting, and ELISA.

RESULTS

The SELDI-TOF MS BALF profiles contained 53 unique, reliably detected proteins. Peak intensities of 24 proteins differed significantly between the CF and non-CF samples. They included the neutrophil proteins, alpha-defensin 1 and 2, S100A8, S100A9, and S100A12, as well as novel forms of S100A8 and S100A12 with equivalent C-terminal deletions. Peak intensities of these neutrophil proteins and immunoreactive concentrations of selected examples were significantly higher in CF than non-CF samples.

CONCLUSIONS

Small neutrophil-derived BALF proteins, including novel C-terminal truncated forms of S100A proteins, are easily detected with SELDI-TOF MS. Concentrations of these molecules are abnormally high in early CF lung disease. The data provide new insights into CF lung disease and identify novel proteins strongly associated with CF airway inflammation.

Up-regulation of S100A8 and S100A9 protein in bronchial epithelial cells by lipopolysaccharide

Increased serum levels of the S100A8 (MRP-8) protein have been reported in inflammatory conditions including bacterial infection, arthritis, and cystic fibrosis (CF). This protein is expressed constitutively with S100A9 (MRP-14) in neutrophils and is regulated by inflammatory stimulants. It has been hypothesized that increased inflammatory response to persistent bacterial infection is a major feature of CF lung disease. Therefore, the authors wished to determine the involvement of these two proteins in the innate defense response of the bronchial epithelium to lipopolysaccharide (LPS). Human bronchial epithelial cells (16HBE14o-) and primary bronchial epithelial cells (NHBE) were grown at air-liquid interface (ALI) and stimulated for up to 96 hours with LPS from Pseudomonas aeruginosa. The 16HBE14o- cells responded to LPS with a 2.9-fold increase in S100A8 mRNA production after 12 hours. S100A9 mRNA production was increased by 1.8-fold after 12 hours and 2.9-fold after 24 hours. It was also found that the S100A8 and S100A9 proteins were increased in the secretions of the 16HBE14o- and NHBE cells after LPS stimulation. This finding suggests that S100A8 and S100A9 are involved in the innate defense of the bronchial epithelium.

Proteomic study of human bronchoalveolar lavage fluids from smokers with chronic obstructive pulmonary disease by combining surface-enhanced laser desorption/ionization-mass spectrometry profiling with mass spectrometric protein identification

Bronchoalveolar lavage fluid (BALF) is an important diagnostic source to investigate cellular and molecular changes in the course of lung disorders. The pattern of soluble proteins in BALF obtained from patients at different stages of respiratory disorders may provide deeper insights in the molecular mechanisms of the disease. We used surface-enhanced laser desorption/ionization mass spectrometry (MS) for differential protein display combined with reversed-phase chromatography and subsequent matrix-assisted laser desorption/ionization-MS or nanoliquid chromatography MS/MS analysis for protein identification to compare the protein pattern of BALF samples obtained from ten smokers suffering from chronic obstructive pulmonary disease (COPD), eight clinically asymptomatic smokers, and eight nonsmokers without pulmonary disease. In this context, we were able to identify small proteins and peptides, either differentially expressed or secreted in the course of COPD or in a direct response to cigarette smoke. The concentrations of neutrophil defensins 1 and 2, S100A8 (calgranulin A), and S100A9 (calgranulin B) were elevated in BALFs of smokers with COPD when compared to asymptomatic smokers. Increased concentrations in S100A8 (Calgranulin A), salivary proline-rich peptide P-C, and lysozyme C were detected in BALFs of asymptomatic smokers when compared to nonsmokers, whereas salivary proline-rich peptide P-D and Clara cell phospholipid-binding protein (CC10) were reduced in their concentration. The identified proteins and peptides might be useful in the future as diagnostic markers for smoke-induced lung irritations and COPD.

Phagocyte-specific calcium-binding S100 proteins as clinical laboratory markers of inflammation

The EF-hand homolog family of S100 proteins comprises the largest group of calcium-binding proteins. Within this S100 family, the phagocyte-specific calcium-binding proteins are pro-inflammatory molecules expressed and secreted by phagocytes, which play a pivotal role within the innate immune system. Although the exact biological functions of these proteins still remain to be defined in greater detail, there is evidence that they are involved in a pro-inflammatory axis associated with various inflammatory conditions. The three members of this group, S100A8, S100A9 and S100A12 are overexpressed at local sites of inflammation. High concentrations are found in synovial fluid, sputum, stool and blood plasma/serum during inflammation. Both the S100A8/S100A9 complex and S100A12 have been proven to be useful as diagnostic markers of inflammation especially in non-infectious inflammatory diseases such as arthritis, chronic inflammatory lung and bowel disease. They indicate phagocyte activation more sensitively than conventional parameters of inflammation. As a consequence, there is a strong correlation to the inflammation of various acute and chronic disorders, making these proteins sensitive parameters for the monitoring of disease activity and response to treatment in individual patients. The phagocyte-specific S100 proteins are able to indicate minimal residual inflammation, which is not detected by other diagnostic tests, and they may even be prospective markers for the outcome of patients. In this review, pro-inflammatory functions of S100 proteins and their usefulness as biomarkers of inflammation are presented.

Pathophysiologic consequences following inhibition of a CFTR-dependent developmental cascade in the lung

Background

Examination of late gestation developmental genes in vivo may be limited by early embryonic lethality and compensatory mechanisms. This problem is particularly apparent in evaluating the developmental role of the cystic fibrosis transmembrane conductance regulator (CFTR) gene in the cystic fibrosis (CF) phenotype. A previously described transient in utero knockout (TIUKO) technology was used to address the developmental role of CFTR in the rat lung.

Results

Rat fetuses transiently treated with antisense cftr in utero developed pathology that replicated aspects of the human CF phenotype. The TIUKO CF rat developed lung fibrosis, chronic inflammation, reactive airway disease, and the CF Antigen (MRP8/14), a marker for CF in human patients, was expressed.

Conclusions

The transient in utero antisense technology can be used to evaluate genes that exhibit either early lethality or compensating gene phenotypes. In the lung CFTR is part of a developmental cascade for normal secretory cell differentiation. Absence of CFTR results in a constitutive inflammatory process that is involved in some aspects of CF pathophysiology.

S100A9 deficiency alters adenosine-5'-triphosphate induced calcium signalling but does not generally interfere with calcium and zinc homeostasis in murine neutrophils

The two calcium- and zinc-binding proteins, S100A9 and S100 A8, abundant in myeloid cells are considered to play important roles in both calcium signalling and zinc homeostasis. Polymorphonuclear neutrophils from S100A9 ko mice are also devoid of S100A8. Therefore, S100A9-deficient neutrophils were used as a model to study the role of the two S100 proteins in the neutrophils's calcium and zinc metabolism. Analysis of the intracellular zinc level upon pyrithione and (+/-)-(E)-methyl-2-[(E)-hydroxyimino]-5-nitro-6-methoxy-3-hexeneamide (NOR-1) treatment revealed no differences between S100A9-deficient and wildtype neutrophils. Similar, the calcium signals were not distinguishable from S100A9-deficient and wildtype neutrophils upon stimulation with platelet activating factor (PAF), thapsigargin or macrophage inflammatory protein 1 alpha (MIP-1 alpha), indicating despite their massive expression S100A8/A9 do neither serve as calcium nor as zinc buffering proteins in granulocytes. In contrast, stimulation with adenosine-5'-triphosphate (ATP) induces a significant stronger increase of the intracellular free calcium level in S100A9-deficient cells compared to wildtype cells. Moreover, the ATP-induced calcium signal was still different when the cells were incubated in calcium free buffer suggesting that pirinergic receptors of the P(2Y) class could be involved in this signalling pathway.

Toll-like receptor 2 represses nonpilus adhesin-induced signaling in acute infections with the Pseudomonas aeruginosa pilA mutant

Expression of pili and associated proteins is an important means of host invasion by bacterial pathogens. Recent evidence has suggested that the binding of Pseudomonas aeruginosa through nonpilus adhesins may also be important in respiratory diseases, since adhesins bind mucins. Using wild-type C57BL/6 and TLR2KO mice, we compared the induction levels of the host response to P. aeruginosa that either expressed pili or lacked pilus expression due to a mutation in the structural gene pilA. In C57BL/6 mice, deletion of pili led to a decreased immune response, evidenced by a lower secretion of cytokines and a lack of neutrophil chemotaxis. By contrast, the P. aeruginosa pilA mutant induced a hyperresponsive phenotype in TLR2KO mice. TLR2KO mice showed an increased number of neutrophils in lavage fluid compared to the levels seen when either mouse strain was exposed to wild-type P. aeruginosa. Further analysis indicated that the increased neutrophil influx was associated with an increased expression of calgranulins, possibly through an induction of Toll-like receptor 4 (TLR4) expression. The hyperresponsive phenotype of TLR2KO mice exposed to the P. aeruginosa pilA mutant was associated with TLR4 induction and indicated that nonpilus adhesin-induced signaling was repressed by TLR2 function and, if not blocked by the host, could induce airway hyperresponsiveness.

Probing the S100 protein family through genomic and functional analysis

The EF-hand superfamily of calcium binding proteins includes the S100, calcium binding protein, and troponin subfamilies. This study represents a genome, structure, and expression analysis of the S100 protein family, in mouse, human, and rat. We confirm the high level of conservation between mammalian sequences but show that four members, including S100A12, are present only in the human genome. We describe three new members of the S100 family in the three species and their locations within the S100 genomic clusters and propose a revised nomenclature and phylogenetic relationship between members of the EF-hand superfamily. Two of the three new genes were induced in bone-marrow-derived macrophages activated with bacterial lipopolysaccharide, suggesting a role in inflammation. Normal human and murine tissue distribution profiles indicate that some members of the family are expressed in a specific manner, whereas others are more ubiquitous. Structure-function analysis of the chemotactic properties of murine S100A8 and human S100A12, particularly within the active hinge domain, suggests that the human protein is the functional homolog of the murine protein. Strong similarities between the promoter regions of human S100A12 and murine S100A8 support this possibility. This study provides insights into the possible processes of evolution of the EF-hand protein superfamily. Evolution of the S100 proteins appears to have occurred in a modular fashion, also seen in other protein families such as the C2H2-type zinc-finger family.

S100A9/S100A8: Myeloid representatives of the S100 protein family as prominent players in innate immunity

Neutrophils are rapidly recruited to sites of inflammation and are thereby at the forefront of the organism's defense against numerous attacks. As unspecific phagocytes, they belong to the so-called innate immunity. Two S100 proteins, namely S100A9 (MRP14) and S100A8 (MRP8), constitute roughly 40% of the cytosolic protein in these cells, implying by their pure abundance an important role in the effector functions of neutrophils. However, despite intense research in the past 15 years, the puzzle that may embed both molecules into the neutrophil/monocyte physiology is still incomplete. One reason might be the conformational variability the S100A9 and S100A8 molecules can adopt. They readily form hetero- and homodimeric, trimeric as well as tetrameric complexes, but they evidently do also exert specific functions as monomers. An ever-increasing body of information suggests that S100A9 plays a prominent role in leukocyte trafficking and arachidonic acid metabolism. In addition, elevated levels of S100A9 and S100A8 in body fluids of inflamed tissues strengthen the view that these molecules are important players in fighting inflammation. The aim of this review is to give an update on the current developments concerning the S100A9/S100A8 molecule in biology and medicine.

Preferential expression of reg I beta gene in human adult pancreas

In human pancreas two genes, reg I alpha and reg I beta, have been characterized but only the reg I alpha protein has been isolated from human pancreatic secretion. To examine their respective physiological roles in fetal and adult pancreas we have compared the patterns of gene expression using a specific RT-PCR method. No progressive evolution in the two mRNAs levels was observed during fetal development (16--41 weeks). A discoordinate expression of the two genes was found with a higher level of reg I alpha mRNA in fetus and a higher level of regI beta in adult. In addition, if reg I alpha mRNA level was correlated with the expression of genes encoding exocrine proteins in adults, reg I beta mRNA level presented no correlation with any ductular, endocrine, or exocrine gene expression. In human pancreatic cell lines we showed the only expression of reg I beta gene and protein. All these data suggest that the two reg genes and proteins could play different roles in the pancreas.

Sexual dimorphism of pancreatic gene expression in normal mice

A differential pancreatic behavior observed between male and female mice in diabetes and pancreatitis led us to study the gene and protein expressions of endocrine and exocrine pancreatic proteins in normal mice. We compared the levels of expression of six pancreatic genes and of four of the corresponding proteins in male and female mice OF1. Amylase gene expression was found to be significantly higher in females than in males, whereas trypsinogen and lipase gene expression were significantly lower. For chymotrypsinogen, reg, and insulin the differences were not significant. This sexual dimorphism did not exist in rat pancreas, where no gender difference was observed. After characterization of mice enzymes by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and antibodies directed to the closely related human pancreatic enzymes, we have compared the levels of these proteins in mice pancreatic homogenates. No significant difference was observed between males and females at the level of protein expression. These data suggest a hormonal sexual difference in the regulation of pancreatic protein synthesis at the pre- and posttranscriptional levels in normal mice, which may play a role in the development of mice pancreatic diseases.

Developmental gene expression and immunohistochemical study of the human endocrine pancreas during fetal life

The development of human endocrine pancreas has been the subject of many immunohistochemical studies but very little is known at the molecular level. We have determined the patterns of gene expression of glucagon, somatostatin and pancreatic polypeptide during fetal life (16-41 weeks of gestation) using the dot-blot hybridization method. In spite of some dispersion in the mRNA levels, no progressive increase or decrease during this period of fetal life could be found, as previously observed for insulin. In keeping with these molecular data, no increase in immunostaining of the four hormones was observed, but a dispersion of endocrine cells within the exocrine tissue was noticed at 20 weeks of gestation followed by a clear differentiation of the Langerhans islets at 31 weeks. Interestingly, the mRNA levels of the four hormones were always higher in the fetal pancreas than in the adult pancreas.

A quantitative multistandard reverse transcriptase-polymerase chain reaction assay of the cystic fibrosis transmembrane conductance regulator: its usefulness in studying efficiency of gene transfer

Procedures to quantify cystic fibrosis transmembrane conductance regulator (CFTR) mRNA levels have already been described but are not universally accepted, and many investigators are skeptical about quantification. To be able to accurately monitor gene therapy, we developed a quantitative multistandard RT-PCR method. This was based on the observation that the CFTR and ribosomal phosphoprotein PO (PR-PO) genes have retained important sequence homologies between rat and human species, allowing the use of rat RNA as an internal standard. A mixture of rat and human RNAs is simultaneously reverse-transcribed in one reaction tube and amplification of CFTR leads to rat and human amplificates with identical sizes which will be discriminated by restriction analysis. PR-PO is analyzed similarly and serves as a control of template loading. RT-PCR of different amounts of RNAs gave similar CFTR/PR-PO ratios, with a coefficient variation below 10%. This technique was applied to a cell line of cystic fibrosis tracheal gland serous cells (CF-KM4) incubated with a recombinant adenovirus containing the CFTR cDNA. Kinetics and dose dependency of transgene expression could be accurately quantified. This method is precise, reproducible, and very simple and could be applied to monitor gene therapy in minute amounts of tissue such as biopsies from cystic fibrosis patients.

G551D cystic fibrosis mice exhibit abnormal regulation of inflammation in lungs and macrophages

The major cause of death in cystic fibrosis (CF) is chronic lung disease associated with persistent infection by the bacterium, Pseudomonas aeruginosa. S100A8, an S-100 calcium-binding protein with chemotactic activity, is constitutively expressed in the lungs and serum of CF patients. Levels of S100A8 mRNA were found to be three to four times higher in the lungs of mice carrying the G551D mutation in CF transmembrane conductance regulator compared with littermate controls. Intravenous injection of bacterial LPS induced S100A8 mRNA in the lung to a greater extent in G551D mice than in wild-type littermates. Localization of S100A8 mRNA and protein in the lung indicate that it is a marker for neutrophil accumulation. Bone marrow-derived macrophages from G551D mice were shown to also exhibit hypersensitivity to LPS, measured by induction of TNF-alpha. These results provide evidence that the pathology of CF relates to abnormal regulation of the immune system.

A cystic fibrosis tracheal gland cell line, CF-KM4. Correction by adenovirus-mediated CFTR gene transfer

Human tracheal gland serous (HTGS) cells are now considered one principal pulmonary target for the gene therapy of cystic fibrosis (CF). We developed a CF tracheal gland serous cell line, CF-KM4, obtained by the transformation of primary cultures of CF tracheal gland serous cells homozygous for the DeltaF508 mutation by using the wild-type SV40 virus. This cell line retained epithelial and secretory features of the native CF-HTGS cells in primary culture, namely, presence of cytokeratin, constitutive secretion of secretory leukocyte proteinase inhibitor, absence of responsiveness to carbachol and isoproterenol, and defective cyclic adenosine monophosphate-dependent chloride channel activity. Adenovirus-mediated CF transmembrane conductance regulator (CFTR) gene transfer into CF-KM4 cells corrected the defective chloride channel activity as well as the responsiveness to adrenergic and cholinergic agonists. In contrast, control transfection using adenovirus-mediated beta-galactosidase gene transfer was totally ineffective. In conclusion, these results present a stable CF tracheal gland cell line that has retained its epithelial and CF-specific defective secretory characteristics which are corrected after CFTR gene transfer. This cell line therefore appears to be a useful tool for large-scale molecular and cellular pharmacologic investigations designed to test potential therapies of the disease CF.

High lysosomal activities in cystic fibrosis tracheal gland cells corrected by adenovirus-mediated CFTR gene transfer

Human tracheal gland serous (HTGS) cells are now believed to be a major target of cystic fibrosis (CF) gene therapy. To evaluate the efficiency of adenovirus-mediated gene transfer in these cells we tested the adenovirus construction containing beta-galactosidase cDNA. We observed that the endogenous beta-galactosidase activity in cultured CF-HTGS cells was too strong to allow us to detect any exogenous beta-galactosidase activity. Immunohistological study on sections of human tracheal tissue confirmed the presence of beta-galactosidase in the serous component of the submucosal glands. We then looked for other lysosomal activities in normal and CF-HTGS cells. We showed that normal cells already have elevated enzyme values and that CF-HTGS cells contained 2-4-fold more beta-galactosidase, alpha-fucosidase, alpha-mannosidase and beta-glucuronidase activities than normal cells. An analysis of their kinetic constants has shown that this difference could be attributed to a lower K(m) of CF lysosomal enzymes. More importantly, these differences are eliminated after adenovirus-mediated CFTR gene transfer and not after beta-galactosidase gene transfer.

Oligomerization and divalent ion binding properties of the S100P protein: a Ca2+/Mg2+-switch model

S100P is a 95 amino acid residue protein which belongs to the S100 family of proteins containing two putative EF-hand Ca2+-binding motifs. In order to characterize conformational properties of S100P in the presence and absence of divalent cations (Ca2+, Mg2+ and Zn2+) in solution, we have analyzed hydrodynamic and spectroscopic characteristics of wild-type and several variants (Y18F, Y88F and C85S) of S100P using equilibrium centrifugation, gel-filtration chromatography, circular dichroism and fluorescence spectroscopies. Analysis of the experimental data shows the following. (1) In agreement with the predictions there are two Ca2+-binding sites in the S100P molecule with different affinity; the high affinity binding site has an apparent binding constant of approximately 10(7) M-1 and the low affinity binding site has an apparent binding constant of approximately 10(4) M-1. (2) The high and low affinity Ca2+-binding sites are located in the C and N-terminal parts of the S100P molecule, respectively. (3) These C and N-terminal sites can also bind other divalent ions. The C-terminal site binds Zn2+ (with relatively low affinity approximately 10(3) M-1), but not Mg2+. The N-terminal site binds Mg2+ with the apparent binding constant approximately 10(2) M-1. (4) Binding of Ca2+ to the C-terminal site and binding of Mg2+ to the N-terminal site occur in the physiological concentration range of these ions (micromolar for Ca2+ and millimolar for Mg2+). (5) Oligomerization state of the S100P molecule appears to change upon addition of Ca2+. On the basis of these observations a plausible model for S100P as a Ca2+/Mg2+ switch has been proposed.

Cloning, overexpression, purification, and spectroscopic characterization of human S100P

The calcium-binding protein S100P has been found to be associated with human prostate cancer. We have overexpressed S100P in Escherichia coli using a T7 expression system. A rapid two-step procedure for the isolation of overexpressed S100P leads to a preparation of >95% pure protein with a yield of approximately 150 mg per liter of culture. The structural integrity of recombinant S100P was analyzed using CD and fluorescence spectroscopic techniques. The far-UV CD shows that secondary structure of recombinant S100P consists predominantly of a-helical structure. Both near-UV CD and tyrosine fluorescence spectra show that aromatic residues are involved in the formation of a specific, well packed structure, indicating that the recombinant S100P protein adopts a compact folded conformation. Ca2+ has a profound effect on S100P structure. Near-UV CD and fluorescence intensity of both internal (tyrosine) and external (ANS) probes suggest significant structural rearrangements in the tertiary structure of the molecule. The similarity of far-UV CD spectrum of S100P in the presence and in the absence of Ca2+ suggests that Ca2+ binding has only minor effects on secondary structure.

Altered cytokine production by cystic fibrosis tracheal gland serous cells

Human submucosal tracheal glands are now believed to play a major role in the physiopathology of cystic fibrosis (CF). We successfully developed techniques for culturing human tracheal gland serous cells from normal individuals (HTGS cells) and from CF patients (CF-HTGS cells) and have shown that the cultured cells have retained most of their in vivo epithelial and secretory characteristics. In order to determine to what extent the serous cells may participate in the lung defense against infection, we examined the effects of the lipopolysaccharide (LPS) of Pseudomonas aeruginosa on HTGS and CF-HTGS cells, with special reference to tumor necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6), and IL-8 secretion. HTGS cells showed a daily basal secretion of IL-6 (1.68 +/- 0.14 ng/10(6) cells) and IL-8 (9.6 +/- 1.3 ng/10(6) cells) and no constitutive secretion of TNF-alpha. Treatment with P. aeruginosa LPS resulted in a significant increase in the basal production of IL-6 (increase of 200% +/- 12%) and IL-8 (525% +/- 40%) as well as a rapid production of TNF-alpha (250 +/- 38 pg/10(6) cells). The LPS-induced secretion of IL-6 and IL-8, but not that of TNF-alpha, was inhibited by glucocorticoids. CF-HTGS cells showed a much higher basal secretion of IL-6 (13.2 +/- 0.5 ng/10(6) cells) and IL-8 (45.6 +/- 7.2 ng/10(6) cells) than normal cells. Treatment with the LPS of P. aeruginosa induced increased production of IL-6 (increase of 100% +/- 8%) and IL-8 (55% +/- 18%) but did not induce the secretion of TNF-alpha. Neither intracellular TNF-alpha nor TNF-alpha transcripts were found in CF-HTGS cells, whereas they were found in normal HTGS cells. In addition, dexamethasone was found to stimulate IL-6 and IL-8 secretion (in the presence or absence of LPS) but did not induce any secretion of TNF-alpha. All these data indicate that HTGS cells are responsive to P. aeruginosa LPS, which results in an increased secretion of IL-6, IL-8, and TNF-alpha, the secretion of which appeared to be impaired in CF-HTGS cells.

Ca2+-dependent interaction of S100A2 with muscle and nonmuscle tropomyosins

Zero-length chemical crosslinking with 1-ethyl-3-[3-(dimethyl amino)propyl]carbodiimide (EDC) indicated an association of the Ca2+-binding protein S100A2 with tropomyosin (TM) in vitro. The mobility of the crosslinked product on SDS-PAGE gels indicated the formation of a 1:1 complex between S100A2 and TM and the interaction was Ca2+ dependent. Monoclonal antibodies were raised against S100A2 and used to determine its cellular localization in the porcine epithelial cell line LLC PK1. It was found that the localization of S100A2 depended on the differentiation state of the cells, being absent from actin stress fibers in sparsely seeded cultures, but present in the actin-containing microvilli characteristic of differentiated cells. Immunoprecipitations of [35S]methionine-labeled extracts using S100A2 as well as TM-specific antibodies failed to co-precipitate TM and S100A2, indicating a transient association between these two molecules in solution. Affinity chromatography of cell extracts on immobilized recombinant TMs, however, confirmed the Ca2+-dependent interaction between S100A2 and both muscle TMs as well as with high and low molecular mass nonmuscle TMs, suggesting that the binding site resides in one of the conserved regions of TM. Our data demonstrate the possible interaction of S100A2 with TM that is not bound to the microfilaments and indicate a differentiation-related function for S100A2 in LLC PK1 cells. The possible functional implications of this interaction are discussed.

Expression of the S-100 proteins MRP-8 and -14 in ischemic brain lesions

So far, microglial activation in cerebral ischemia has only been studied in different animal models. We have investigated the activation of microglial cells in human cerebral ischemia. As a marker for the activation of these "brain macrophages," we have used the macrophage inhibitor factor-related-proteins MRP-8 and MRP-14, which belong to the calcium binding S-100 protein family. The proteins can be detected on microglial cells in bacterial encephalitis and Alzheimer's disease but have so far not been studied in non-inflammatory diseases, in which microglial activation also occurs. Antibodies against MRP-8 and -14 detected ramified microglial cells within the first 3 days after cerebral infarction. Labeled cells were found selectively in the periinfarctional area. To support the notion that these cells belong to the locally activated resident microglial population, we studied their proliferation rate by staining the Ki-67 antigen with the antibody MIB-1. Double-labeling clearly showed that in the early phase of cerebral infarction microglial cells in the periinfarctional area express MRP-8 and -14 and also proliferate. Surprisingly, MRPs are expressed no longer than 3 days post infarction. This indicates that the activation of the resident microglia is an early step of tissue reaction after cerebral infarction. Additionally, we found evidence that microglial cells contribute to the population of phagocytes only during the first 3 days post infarction. The majority of lipid phagocytes found in the later stages are obviously recruited from the blood-borne macrophage pool.

Developmental gene expression of trypsinogen and lipase in human fetal pancreas

BACKGROUND

Very few studies have been reported on the expression of human pancreatic genes during fetal development. We have shown very low lipase immunoreactivity compared with elevated trypsinogen immunoreactivity in a previous immunohistological study of human fetal pancreas during development.

METHODS

The expression of these two selectively expressed genes of the exocrine pancreas, trypsinogen and lipase were investigated. The developmental profiles of the corresponding mRNA's were determined from the 13th gestational week.

RESULTS

For the two genes, fetal mRNA levels throughout gestation remained significantly lower than the corresponding adult levels. No correlation was found between trypsinogen and lipase gene expression in the fetal pancreas, whereas such a correlation was present in adult pancreas. This may be explained by differences in maturity of the pancreas.

Intracellular free Ca2+ dynamic changes to histamine are reduced in cystic fibrosis human tracheal gland cells

This study documents a difference between cystic fibrosis human (CF-HTG) and normal human (HTG) tracheal gland cells: the ability of histamine to induce an increase of intracellular free calcium concentration [Ca2+]i was abnormally reduced in CF-HTG cells. The magnitude of the [Ca2+]i peak rise in response to histamine is smaller in CF-HTG cells than in HTG cells, and the percentage of CF-HTG cells that increase [Ca2+]i is decreased compared with HTG cells. In contrast to histamine, the human neutrophil elastase (HNE) stimulation of both CF-HTG and HTG cells generated [Ca2+]i asynchronous oscillations and the magnitude of the peak [Ca2+]i response as well as the percentage of responding cells were similar for both groups. By videomicroscopy observations, the secretory response (exocytosis of secretion granules) of CF-HTG cells occurred with HNE, but not with histamine, thus suggesting that [Ca2+]i asynchronous oscillations may be linked to the exocytosis process in human tracheal gland cells.

The S100 family of EF-hand calcium-binding proteins: functions and pathology

Calcium lons as second messengers control many biological processes, at least in part, via interaction with a large number of Ca(2+)-binding proteins. One class of these proteins shares a common Ca(2+)-binding motif, the EF-hand, Here, we describe some functional aspects of EF-hand proteins, which have been found recently in different cellular compartments. Novel links between EF-hand proteins, particularly S100 proteins, and specific diseases are now emerging.

Absence of correlation between reg and insulin gene expression in pancreas during fetal development

The reg gene characterized in the exocrine pancreas has been found to be expressed in regenerating islets of 90% depancreatized rats and not in normal islets. In humans, it was identified only in the exocrine pancreas. Because the reg protein has been found to be related to islet cell replication and/or beta cell regeneration, we compared the expression of the reg gene with that of chymotrypsinogen of exocrine origin and insulin of endocrine origin. We investigated the expression of the three pancreatic genes in the fetal pancreas during human development using dot-blot analysis. The levels of expression of the corresponding mRNAs did not appear to undergo great changes between the 17th and the 29th wk of gestation. Nevertheless, the fetal mRNA levels for reg and chymotrypsinogen were below that of the adult, with very low levels of reg gene expression in more than half of the studied pancreases. In contrast, the insulin mRNA levels were significantly higher in fetal than in adult pancreases, suggesting that insulin may function as a growth factor during fetal development. Our results indicate that no correlation between reg and insulin gene expression exists in the fetal pancreas during the developmental period studied but, on the contrary, such a correlation was present in the adult pancreas.