Isolation and characterization of the chicken trypsinogen gene family

Purification and characterization of a serine protease from organic dust and elucidation of its inductive effects on lung inflammatory mediators

Organic dust inhalation is associated with the development of respiratory diseases. Serine protease activities in organic dusts were previously reported to contribute to the induction of lung inflammatory mediators however, the identities of the proteases and the mechanisms by which they induce inflammatory mediators are unknown. The goal of this study was to purify and characterize serine protease(s) from organic dust and elucidate mechanisms by which they induce lung inflammatory mediators. A serine protease was purified from poultry organic dust by benzamidine-agarose affinity chromatography. Mass spectrometry and amino-terminal sequence analysis identified the purified protease as chicken trypsin II-P29. Purified protease induced proinflammatory cytokine levels in Beas2B and NHBE epithelial and THP-1 macrophage cells. Treatment with the purified protease increased cellular and mitochondrial reactive oxygen species (ROS) generation. Induction of inflammatory mediators and ROS were suppressed by serine protease inhibitors and antioxidants. Purified protease activated protein kinase C (PKC), mitogen-activated protein kinase (MAPK)1/3 and MAPK14 signaling, and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and signal transducer and activator of transcription 3 (Stat-3), and chemical inhibitors targeting these pathways suppressed induction of inflammatory mediators. Calcium mobilization studies showed that the purified protease activated protease-activated receptors (PAR) F2R, F2RL1, F2RL2, F2RL3, and F2R and F2RL1 knockdown suppressed the induction of inflammatory mediators. Intranasal instillation of purified protease increased lung chemokine (C-X-C motif) ligand (CXCL)1, interleukin (IL)-6, and tumor necrosis factor (TNF) levels in mice. Our studies have shown that chicken trypsin is a proinflammatory constituent of poultry organic dust, and induces lung inflammatory mediators via increased ROS and PAR activation in a cell signaling pathway involving PKC, MAPK1/3 and MAPK14, and NF-κB and Stat-3.NEW & NOTEWORTHY Inhalation of dust in industrial agricultural operations is linked to the development of lung diseases. Our studies have isolated for the first time a trypsin protease from poultry farm dust and have shown that it stimulates lung inflammation. The protease stimulates the production of oxidants and cell signaling pathways to increase inflammatory mediator production. Targeting trypsin protease in poultry farm environment may be a useful strategy to counter the harmful effects of dust.

Poultry nutrition

Nutrition is the most important environmental factor affecting development, health status, growth performance and profitability of poultry production. Feeds for poultry constitute up to 70–75% of total production costs. Poultry nutrition differs considerably from that of other livestock, which is determined by the specific anatomy of the gastrointestinal tract. Protein, energy, fat, fiber, minerals, vitamins, and water are of basic importance for poultry nutrition and their content in feeds must cover the requirement that differ depending on the bird’s age and species. In general, feed protein must be of good value including the content of essential amino acids. Among them lysine, methionine, cysteine, threonine and tryptophan are the limiting ones. The main ingredient of poultry feeds are cereal grains, i.e. wheat and maize, which predominantly constitute an energy source because their protein content is insufficient for birds. Because of that cereals cannot be the only feed for poultry and must be combined with protein sources such as soybean or rapeseed meal, legume seeds or protein concentrates. Despite birds’ requirement for nutrients and chemical composition of feeds are well known, nutrition must face many problems. One of the most important issues is to find alternatives to antibiotic growth promoters.

Digestion dynamics in broilers fed rapeseed meal

Rapeseed proteins are described to be poorly digestible in chickens. To further identify some molecular locks that may limit their use in poultry nutrition, we conducted a proteomic study on the various chicken digestive contents and proposed an integrative view of the proteins recruited in the crop, proventriculus/gizzard, duodenum, jejunum, and ileum for digestion of rapeseed by-products. Twenty-seven distinct rapeseed proteins were identified in the hydrosoluble fraction of the feed prior ingestion. The number of rapeseed proteins identified in digestive contents decreases throughout the digestion process while some are progressively solubilized in the most distal digestive segment, likely due to a combined effect of pH and activity of specific hydrolytic enzymes. Fifteen chicken proteins were identified in the hydrosoluble proventriculus/gizzard content, including chymotrypsin-like elastase and pepsin. Interestingly, on the 69 distinct proteins identified in duodenum, only 9 were proteolytic enzymes, whereas the others were associated with homeostasis, and carbohydrate, lipid, vitamin and hormone metabolisms. In contrast, chicken proteins identified in jejunal and ileal contents were mostly proteases and peptidases. The present work highlights the relevance of using integrative proteomics applied to the entire digestive tract to better appreciate the protein profile and functions of each digestive segment.

Exploring the in vivo digestion of plant proteins in broiler chickens

The use of various protein sources (industry by-products, proteaginous) in poultry diets requires a greater understanding of protein digestion mechanisms. The aim of this study was to characterize the molecular actors required for protein digestion in broilers fed 4 different diets containing soybean meal, rapeseed meal, pea, or corn distiller's dried grain with solubles as the only protein source. The digesta of the digestive tract segments were collected and soluble proteins were analyzed by SDS-PAGE. SDS-PAGE analyses revealed 5 ubiquitous bands in digesta of all digestive tract segments regardless of the diet, whereas 3 bands were diet-specific. The digesta of the jejunum were further submitted to proteomic analysis. Forty-two proteins of chicken origin and 17 plant proteins were identified in digesta samples by mass spectrometry. Fifteen proteins of chicken origin were specific to one diet and 18 were common to all diets. By homology with mammals, these proteins are thought to be involved in protein, lipid, carbohydrate, and nucleic acid metabolism and also in intestinal homeostasis. Some of the 17 plant proteins were found to be not fully digested (soybean meal, rapeseed meal, and pea diets) and others were identified as protease inhibitors (soybean meal and pea diets). This study provides a comprehensive analysis of the physiological proteins involved in the digestion of 4 protein sources used in broiler diets. Such an approach, combined with the analysis of insoluble components of these different protein sources, would contribute to define whether these protein sources could be more largely used in poultry nutrition. It also would allow identifying ways to improve their digestibility in broiler chickens (feed additives such as exogenous proteases or processing to inactivate anti-nutritional factors, for instance).

Express Sequence Tag Analysis - Identification of Anseriformes Trypsin Genes from Full-Length cDNA Library of the Duck (Anas platyrhynchos) and Characterization of Their Structure and Function

Trypsins are key proteins important in animal protein digestion by breaking down the peptide bonds on the carboxyl side of lysine and arginine residues, hence it has been used widely in various biotechnological processes. In the current study, a full-length cDNA library with capacity of 5·10(5) CFU/ml from the duck (Anas platyrhynchos) was constructed. Using express sequence tag (EST) sequencing, genes coding two trypsins were identified and two full-length trypsin cDNAs were then obtained by rapid-amplification of cDNA end (RACE)-PCR. Using Blast, they were classified into the trypsin I and II subfamilies, but both encoded a signal peptide, an activation peptide, and a 223-a.a. mature protein located in the C-terminus. The two deduced mature proteins were designated as trypsin-IAP and trypsin-IIAP, and their theoretical isoelectric points (pI) and molecular weights (MW) were 7.99/23466.4 Da and 4.65/24066.0 Da, respectively. Molecular characterizations of genes were further performed by detailed bioinformatics analysis. Phylogenetic analysis revealed that trypsin-IIAP has an evolution pattern distinct from trypsin-IAP, suggesting its evolutionary advantage. Then the duck trypsin-IIAP was expressed in an Escherichia coli system, and its kinetic parameters were measured. The three dimensional structures of trypsin-IAP and trypsin-IIAP were predicted by homology modeling, and the conserved residues required for functionality were identified. Two loops controlling the specificity of the trypsin and the substrate-binding pocket represented in the model are almost identical in primary sequences and backbone tertiary structures of the trypsin families.

Maternally derived trypsin may have multiple functions in the early development of turbot (Scopthalmus maximus)

Trypsin is an important serine protease that is considered to be involved in digestion of protein in teleost fish. Nevertheless, studies on trypsin/trypsinogen in fish embryos are very limited. In this study, the trypsinogen of turbot (Scophthalmus maximus) (tTG) was identified and the expression patterns and activity of trypsinogen/trypsin were investigated. The results showed that the tTG mRNA was evenly distributed in the oocytes and was also expressed along the yolk periphery in early embryos. At later embryo stages and 1 days after hatching (dph), the tTG mRNA concentrated at the alimentary tract and head. Quantitative expression analysis showed that the tTG transcripts decreased after fertilization until the gastrula stage, then increased with the embryo and larvae development. This result was also confirmed by the specific activity analysis of trypsin and in-situ-hybridization (ISH). All of the results indicated that tTG in early embryo stages was maternally derived and expressed by itself after gastrula stages. Additionally, location of tTG mRNA in embryos and larvae was investigated; we considered that trypsin may have multiple functions during the embryo development process. Based on our results regarding trypsinogen in embryos and early development, we concluded that the trypsin/trypsinogen in turbot embryos was inherited from a maternal source and we suggested that trypsin in early development has multiple functions in the process of development.

Molecular cloning, expression, and anti-tumor activity of a novel serine protease from Arenicola cristata

Arenicola cristata, a marine annelid, is a well-known and prized traditional Chinese medicine. However, the serine protease gene of A. cristata has not been cloned yet. In this study, a novel protease of A. cristata was cloned, sequenced, and expressed in Escherichia coli, and the functions of this recombinant protease were also investigated. The whole complementary DNA (cDNA) of this novel protease was of 980 bp in length and consisted of an open reading frame of 861 bp encoding 286 aa. Sequence analysis of the deduced amino acid sequence revealed that the protease belongs to the serine protease family. The active enzyme of the proposed A. cristata protease is composed of a signal peptide, a propeptide, and a mature polypeptide. The molecular weight of the recombinant mature protein was ~26 kDa after over-expression in E. coli. The recombinant protein significantly inhibited cell growth and induced cell apoptosis of esophageal squamous cell carcinoma (ESCC) in vitro, and reduced tumorigenicity in vivo. Furthermore, administration of the recombinant protein led to the activation of caspase-9 as well as down-regulation of Mcl-1 and Bcl-2. Taken together, our findings indicated that the recombinant serine protease of A. cristata could inhibit ESCC cell growth by mitochondrial apoptotic pathway and might act as a potential pharmacological agent for ESCC therapy.

Four serine protease cDNAs from the midgut of Plutella xylostella and their proteinase activity are influenced by the endoparasitoid, cotesia vestalis

Serine proteinases, which include trypsins and chymotrypsins, play numerous roles in lepidopteran larvae, such as digestion, zymogen activation, and immune defense. Studies of lepidopteran serine proteinases could increase understanding of their feeding preference (polyphagous and monophagous) and facilitate identification of protease inhibitors, which can be engineered for pest management. In this paper, four full-length cDNAs encoding one chymotrypsin and three trypsins were cloned from larval midguts of the diamondback moth, Plutella xylostella. Real-time quantitative polymerase chain reaction (PCR) analysis showed all four serine protease genes were downregulated after P. xylostella was parasitized by the parasitoid wasp Cotesia vestalis. Trypsin and chymotrypsin enzymatic activities within the midgut of nonparasitized and C. vestalis-parasitized P. xylostella larvae were examined using N-a-benzoyl-arg p-nitroanilide and N-succinyl-ala-ala-pro-phe p-nitroanilide as substrates. Trypsin and chymotrypsin activities were decreased in parasitized larvae as compared to untreated larvae, with the effect being more pronounced over time. Chymotrypsin activity in particular exhibited a significant decrease in activity. The correlation of decreased enzymatic activity and transcript abundance suggests parasitization induced downregulation of serine proteinase gene transcripts.

Cloning and characterization of trypsin- and chymotrypsin-like genes in the striped rice stem borer, Chilo suppressalis

Serine proteinases including trypsins and chymotrypsins play various important roles in insects, including food digestion, immune defense, and zymogen activation. Studies on insect serine proteinases could reveal their feeding preference (polyphagous and monophagous) and facilitate identification of protease inhibitors, which can be engineered for pest management. In this paper, 11 transcripts encoding trypsin- and chymotrypsin-like proteins were cloned from the striped rice stem borer, Chilo suppressalis (Walker). All the predicted proteins share high sequence similarity with known trypsin- and chymotrypsin-like proteins from either lepidopterans or dipterans, and most of the proteins have conserved motifs that are characteristics of serine proteinases. Among the 11 cloned genes, six were expressed predominantly and one exclusively in the midgut of the insect, three were expressed relatively evenly in examined tissues, and one was not expressed in either the gut or hemolymph based on RT–PCR results. The seven genes that were predominantly or exclusively expressed in the gut were also affected by feeding on different host plants. The genes that were expressed in the gut and were affected by host plants are likely to encode digestive proteinases. The identification of trypsin- and chymotrypsin-like genes in this insect species is the first step towards further comparative studies and for identification of insect-specific proteinase inhibitors, which might be engineered to protect rice plants against the striped rice stem borer, which is one of the destructive pests of rice.

A trypsin homolog in amphioxus: expression, enzymatic activity and evolution

Trypsin has been documented in a variety of species including both vertebrates and invertebrates, but little is known about it in amphioxus, a model organism for insights into the origin and evolution of vertebrates. Here we identified a trypsin gene in Branchiostoma japonicum. The cDNA was 978 bp long with an ORF encoding a deduced protein of 272 amino acids. The deduced protein had an N-terminal signal peptide of 15 amino acids, a 16 activation peptide with the typical cleavage site Arg/Ile, a Tryp_SPc domain with the catalytic triad His(72)-Asp(118)-Ser(215) and the S1 substrate binding residue Asp(209), which are all characteristic of trypsinogens. The recombinant trypsin protein was able to hydrolyse the trypsin prototypic substrate BAEE, which was inhibited by the trypsin-specific inhibitor soybean trypsin inhibitor. Both northern blotting and tissue-section in situ hybridization demonstrated that trypsin gene was expressed in a tissue-specific manner, with most abundant levels in the hepatic caecum, mid-gut and ovary. And the whole mount in situ hybridization showed that it began to express in the middle third of the full-length primitive gut in 2-day larvae, where the hepatic caecum will form later during development. Phylogenetic analysis indicated that both amphioxus and ascidian trypsins are more closer to each other than to vertebrate trypsins, suggesting a continuous evolutionary divergence of vertebrate trypsins after split from protochordate/vertebrate common ancestor.

Genome-wide survey and evolutionary analysis of trypsin proteases in apicomplexan parasites

Apicomplexa are an extremely diverse group of unicellular organisms that infect humans and other animals. Despite the great advances in combating infectious diseases over the past century, these parasites still have a tremendous social and economic burden on human societies, particularly in tropical and subtropical regions of the world. Proteases from apicomplexa have been characterized at the molecular and cellular levels, and central roles have been proposed for proteases in diverse processes. In this work, 16 new genes encoding for trypsin proteases are identified in 8 apicomplexan genomes by a genome-wide survey. Phylogenetic analysis suggests that these genes were gained through both intracellular gene transfer and vertical gene transfer. Identification, characterization and understanding of the evolutionary origin of protease-mediated processes are crucial to increase the knowledge and improve the strategies for the development of novel chemotherapeutic agents and vaccines.

The guinea pig pancreas secretes a single trypsinogen isoform, which is defective in autoactivation

OBJECTIVES

The aim of the present study was to purify and clone the trypsinogen isoforms from the guinea pig pancreas and characterize their activation properties.

METHODS

Trypsinogens from pancreatic homogenates were isolated by ecotin-affinity chromatography, followed by cation-exchange chromatography. Activation of trypsinogens was tested with enteropeptidase, cathepsin B, and trypsin. Complementary DNAs for pretrypsinogens were cloned from total RNA after reverse transcription and polymerase chain reaction amplification.

RESULTS

Purification of trypsinogens yielded a single peak with an N-terminal amino-acid sequence of LPIDD. Cloning of pretrypsinogen cDNAs revealed 2 distinct but nearly identical isoforms. At the amino acid level, the only difference between the 2 isoforms is an Ala/Ser change at position 15 within the signal peptide. Thus, both cDNA variants give rise to the same mature trypsinogen upon secretion. Guinea pig trypsinogen is readily activated by enteropeptidase and cathepsin B but exhibits essentially no autoactivation, under conditions where human cationic and anionic trypsinogens rapidly autoactivate.

CONCLUSIONS

The observations suggest that multiple trypsinogen isoforms and their ability to autoactivate are not required universally for normal digestive physiology in mammals. Furthermore, the inability of guinea pig trypsinogen to undergo autoactivation suggests that this species might be more resistant to pancreatitis than humans, where increased autoactivation of cationic trypsinogen mutants has been linked to hereditary pancreatitis.

Interchromosomal segmental duplications explain the unusual structure of PRSS3, the gene for an inhibitor-resistant trypsinogen

Homo sapiens possess several trypsinogen or trypsinogen-like genes of which three (PRSS1, PRSS2, and PRSS3) produce functional trypsins in the digestive tract. PRSS1 and PRSS2 are located on chromosome 7q35, while PRSS3 is found on chromosome 9p13. Here, we report a variation of the theme of new gene creation by duplication: the PRSS3 gene was formed by segmental duplications originating from chromosomes 7q35 and 11q24. As a result, PRSS3 transcripts display two variants of exon 1. The PRSS3 transcript whose gene organization most resembles PRSS1 and PRSS2 encodes a functional protein originally named mesotrypsinogen. The other variant is a fusion transcript, called trypsinogen IV. We show that the first exon of trypsinogen IV is derived from the noncoding first exon of LOC120224, a chromosome 11 gene. LOC120224 codes for a widely conserved transmembrane protein of unknown function. Comparative analyses suggest that these interchromosomal duplications occurred after the divergence of Old World monkeys and hominids. PRSS3 transcripts consist of a mixed population of mRNAs, some expressed in the pancreas and encoding an apparently functional trypsinogen and others of unknown function expressed in brain and a variety of other tissues. Analysis of the selection pressures acting on the trypsinogen gene family shows that, while the apparently functional genes are under mild to strong purifying selection overall, a few residues appear under positive selection. These residues could be involved in interactions with inhibitors.

Cloning and expression of ostrich trypsinogen: an avian trypsin with a highly sensitive autolysis site

One of ostrich (Struthio camelus) trypsinogen genes was cloned from pancreatic cDNA. Its amino acid sequence compared to known trypsin sequences from other species shows high identity and suggests that it is a member of the phylogenetically anionic trypsinogen I subfamily. After cytoplasmic over expression in Escherichia coli and renaturation, the activation properties of ostrich trypsinogen were studied and compared to those of human trypsinogen 1 (also called as human cationic trypsinogen). Ostrich trypsinogen undergoes bovine enterokinase activation and autoactivation much faster than human trypsinogen 1 and exhibits on a synthetic substrate a somewhat higher enzymatic activity than the latter one. The most interesting property of ostrich trypsin is its relatively fast autolysis that can be explained via a mechanism different from the common mechanism for rat and human 1 trypsins. The latter proteases have a site, Arg117-Val118, where the autolysis starts and then goes on in a zipper-like fashion. This is absent from ostrich trypsin. Instead it has a couple of cleavage sites within regions 67-98, including two unusual ones, Arg76-Glu77 and Arg83-Ser84. These appear to be hydrolysed fast in a non-consecutive manner. Such an autolysis mechanism could not be inhibited by a single-site mutation which in humans is proposed to lead to pancreatitis.

Organization of the MASP2 locus and its expression profile in mouse and rat

The mouse, rat, and human MASP2 loci are situated on syntenic chromosome regions and are highly conserved. They comprise the genes for MASP-2/ MAp19, TAR DNA binding protein of 43 kDa, FRAP kinase, CDT6, Polymyositis-Scleroderma 100-kDa autoantigen, spermidine synthase, and TERE which were analyzed by annotation of available gene transcript data and cross-species comparison of available genomic sequences. The human and rat genes for spermidine synthase have an additional intron compared to the mouse gene. The mouse and rat genes for Polymyositis-Scleroderma 100-kDa autoantigen have an additional exon compared to the human gene. We find support for the hypothesis that the MAp19-specific exon within the MASP2 gene may have originated in a transposable element. Blocks of highly conserved intronic sequences were found in the MASP2 gene and the TARDBP gene. The expression of all genes within the MASP2 locus was analyzed in mouse and rat. The restricted expression of MASP-2 and MAp19 mRNA in liver contrasts with the ubiquitous expression of all neighboring genes studied.

Gene conversion-like missense mutations in the human cationic trypsinogen gene and insights into the molecular evolution of the human trypsinogen family

Over the past decade, gene conversion has been shown increasingly to be a cause of human disease. Through this process, a functional gene is converted into a mutant by a homologous, nonfunctional one. In this article, we demonstrate that gene conversion is a likely cause of the mutations of the human cationic trypsinogen (PRSS1) gene that are associated with hereditary or sporadic pancreatitis, including the R122H (CGC>CAT: c.365-366 GC>AT), N29I (AAC>ATC: c.86A>T), and A16V (GCC>GTC: c.47C>T) missense mutations. This hypothesis is strongly supported by four lines of observation. First, human group I trypsinogen genes are tandemly repeated and share a high sequence homology between them. Secondly, a possible donor sequence for each variant is present in the PRSS1 gene's paralog(s). Thirdly, there exist uninterrupted sequence tracts ranging from 30 to 114 bp in the putatively converted regions. Finally, Chi-like and palindromic sequences are found in the vicinity of these missense mutations. This theory, if correct, will make the pancreatitis-associated PRSS1 mutations a unique example, as it shows that a functional gene may be converted by several paralogs, and that such an event may even occur between two functional genes (i.e., the N29I mutation), resulting in disease. This adds further to the diversity of genetic mechanisms underlying human disease. In addition, this genetic finding provides, for the first time, concrete evidence of the contribution made by gene conversion to the molecular evolution of the human trypsinogen family.

Sequencing and expression analysis of the serine protease gene cluster located in chromosome 19q13 region

The human kallikrein gene cluster, located in the chromosome band 19q13, contains several tissue-specific serine protease genes including the prostate-specific KLK2, KLK3 and prostase genes. To further characterize the gene cluster, we have mapped, sequenced, and analyzed the genomic sequence from the region. The results of EST database searches and GENSCAN gene prediction analysis reveal 13 serine protease genes and several pseudogenes in the region. Expression analysis by RT-PCR indicates that most of these protease genes are expressed only in a subset of the 35 different normal tissues that have been examined. Several protease genes expressed in skin show higher expression levels in psoriatic lesion samples than in non-lesional skin samples from the same patient. This suggests that the imbalance of a complex protease cascade in skin may contribute to the pathology of disease. The proteases, excluding the kallikrein genes, share approximately 40% of their sequences suggesting that the serine protease gene cluster on chromosome 19q13 arose from ancient gene duplications.

Genomic organisation and polymorphism of a crustacean trypsin multi-gene family

The coding sequences of three trypsin genes, obtained by polymerase chain reaction (PCR), were determined in Penaeus vannamei (Crustacea, Decapoda). These genes were characterised by two short introns, which occur at a position quasi-conserved as the first two introns in vertebrate counterparts. Belonging to three different families, two of the genes are expressed in the digestive gland. A 5' RACE-PCR amplification of hepatopancreatic mRNA, together with the presence of short 5' extensions, confirmed that the third gene family is not expressed in this tissue. The second intron in the genes expressed in the hepatopancreas presents a 5' splice site consensus, beginning with a GC motive which is reported for the first time in trypsin genes and is of phase I in mammals. A high copy number was determined for these genes. Several restricted PCR were performed to describe the polymorphism of these sequences. Five genes were partially sequenced for each family and five genes coding the different, previously described cDNAs were recovered. These sequences also confirm that the third family resembles a mosaic of type I and type II gene families. A high degree of polymorphism in the introns (54-59% identity) among the three families is observed, but mutations in corresponding introns inside each of the families are low (3-6%).