Biomedical subjects
Publications and source records attributed to V Keim.
We have previously reported the coding sequence of the rat PAP II mRNA. We show in this paper the existence in rat pancreas of two forms of PAP II mRNA with identical coding sequence but a different 5'-untranslated region. We demonstrate that this is the result of a differential splicing.
BACKGROUND: The pancreatitis-associated protein (PAP) I and III, but not PAP II, mRNAs are constitutively expressed in the small intestine of rats. METHODS: We studied expression of both PAP I and PAP III mRNAs during development and on nutritional and hormonal manipulations. RESULTS: Between day 20 of gestation and day 21 of age, PAP mRNAs could barely be detected. Their concentrations increased dramatically from day 21 to day 45 of age and remained constant thereafter. Rats adapted to a diet with low carbohydrate content showed a significant decrease in PAP mRNA concentrations. Finally, whereas thyroidectomy and ovariectomy induced a decrease in both mRNA concentrations, and adrenalectomy a limited decrease in PAP III mRNA only, diabetes and castration did not alter the expression of either gene. CONCLUSION: Gene expression of PAP I and III mRNAs is regulated in a coordinate manner in the rat small intestine during development and on nutritional and hormonal manipulations.
BACKGROUND/AIMS: The pancreatitis-associated protein (PAP) is undetectable in normal pancreatic secretion and overexpressed in the acute phase of pancreatitis. We investigated whether serum PAP could be an indicator of the course of acute pancreatitis. METHODS: Serum PAP was retrospectively monitored in 98 patients with acute pancreatitis during their stay in the hospital. Patients were classified according to the severity of their disease as group I (< or = 1 complication), group II (> or = 2 complications), or group III (lethal pancreatitis). RESULTS: At admission, 34% of patients, all from group I, had normal PAP values (< 10 micrograms/L). None of them developed complications. They had a significantly shorter stay in the hospital than patients with elevated PAP (6.2 days vs. 14.9 days). In all patients, serum PAP increased after admission to a maximum, which correlated significantly to the severity of the disease. Average peak values were 22.2 micrograms/L and 240.0 micrograms/L in group I patients with normal or high PAP at admission, 963.0 micrograms/L and 1436.0 micrograms/L in groups II and III. Serum PAP decreased steadily during recovery. CONCLUSIONS: Monitoring serum PAP in patients with acute pancreatitis would provide (1) at admission, selection of most patients who will not develop complications; (2) a dynamic assessment of severity; and (3) anticipation of the patient's recovery.
To study the relation between expression of the pancreatitis-associated protein (PAP) and severity of pancreatitis in rats, different degrees of experimental pancreatitis were induced by a 1-, 3-, or 5-h cerulein infusion (5 micrograms kg-1 h-1). This treatment decreased pancreatic volume secretion to below 10%. Immediately after infusion, the secretion rate increased to approximately 50% of control. Within 1 day, volume and bicarbonate secretion rates were not different from controls. At this point, protein secretion amounted to 30% of control, but only in animals receiving the 3- or 5-h dose. The values increased to 40-60% within 3 days. In all groups, the isoenzyme pattern was not influenced by the cerulein treatment. One day after induction of pancreatitis, the PAP was found in pancreatic juice in concentrations related to the dose of cerulein given. By immunohistochemical techniques, the protein was localized over acinar cells, but was not detectable in interstitial tissue, islets, or in the healthy exocrine pancreas. Pathomorphologic alterations in the pancreas were quantified by a scoring system. One and 2 days after the treatment, a more severe pancreatitis and more elevated levels of PAP were found in animals treated with the higher dose of cerulein. It is concluded that PAP is expressed in the pancreas in relation to the severity of cerulein-induced pancreatitis.
In different tissues alteration of protein synthesis has been observed during acute stress. In this review we characterise the modulation of pancreatic protein synthesis during inflammation. A sustained decrease of mRNA levels of secretory enzymes is accompanied by noncoordinated alterations of protein synthesis during the acute phase and the recovery from pancreatitis. For that regulation both translational and transcriptional alterations are of importance. The most prominent finding was the expression of pancreatitis-associated proteins (PAP) in humans or rats, which are absent in the normal gland but synthesised during acute pancreatitis. PAPs are pancreatic secretory proteins, their mRNA were cloned and sequenced and the sequence of encoded preproteins of 175 amino acids were deduced. The PAP expression increased as a function of the severity of pancreatitis. It can be assayed in serum and may be used as a marker of the disease. Due to its affinity to bacterial surfaces the PAP molecule could act as an endogenous antibiotic factor that prevents the bacterial infection of the inflamed pancreas.
The pancreatitis-associated protein (PAP) is a lectin-related secretory protein present in small amounts in the rat pancreas and overexpressed during the acute phase of pancreatitis. On the other hand, PAP is constitutively expressed in the intestinal tract but not in other tissues. We cloned from a pancreatic cDNA library two overlapping cDNAs encoding a protein structurally related to PAP. This second PAP, which was called PAP II, was the same size as the original PAP (PAP I) and showed 74.3% amino acid homology. Studies on gene expression demonstrated that PAP II mRNA concentration increased within 6 h following induction of pancreatitis, reached maximal levels (> 200 times control values) at 24-48 h, and decreased thereafter, similar to PAP I. However, PAP II mRNA could not be detected in the intestinal tract or in other tissues. We also isolated a PAP II genomic DNA fragment which was characterized over 2.7 kb of gene sequence and 1.9 kb of 5' flanking sequence. The 5' end of the coding sequence was determined by primer extension of the PAP II mRNA. The PAP II coding sequence spanned six exons separated by five introns. Several potential regulatory elements were identified in the promoter region, including two glucocorticoid-response elements and one IL-6-response element. Antibodies raised to a synthetic peptide of PAP II detected a single band in Western blot analysis of the pancreatic secretory proteins from rats with pancreatitis, with a M(r) compatible with the theoretical M(r) of PAP II.(ABSTRACT TRUNCATED AT 250 WORDS)
Rat pancreatitis-associated protein (PAP) mRNA is barely detectable in normal pancreas and overexpressed during acute pancreatitis (Iovanna, J., Orelle, B., Keim, V., and Dagorn J.-C. (1991) J. Biol. Chem. 266, 24664-24669). RNA amplification by reverse-transcriptase-coupled polymerase chain reaction showed that PAP mRNA was constitutively expressed in duodenum, jejunum, and ileum, at similar levels as in pancreas during the acute phase of pancreatitis. A weak expression was also detected in several other tissues. The rat PAP gene was isolated from a genomic library and characterized over 3.2 kilobases of gene sequence and 1.2 kilobases of 5'-flanking sequence. The 5' end of the coding sequence was determined by primer extension of the PAP transcript. Several potential regulatory elements were identified in the promoter region, including a pancreas-specific consensus sequence, two Pan1 (pancreas-specific) transcription activators, two IL-6 response elements, and one glucocorticoid response element. The PAP coding sequence spanned over six exons. The first three exons encoded the 5'-untranslated region of the mRNA, the signal peptide, and 39 amino acids of the NH2-terminal end of the mature protein, respectively. The other three exons encoded a domain of the protein with significant homology to the carbohydrate-recognition domain of animal lectins. Sequence comparison of the PAP gene with 13 carbohydrate-recognition domain-containing genes revealed that they derived from the same ancestor gene. Position of introns within the carbohydrate-recognition domain were different, however, suggesting that PAP belongs to a new group of lectins. These results support the hypothesis that genes encoding PAP and other lectins evolved from a common ancestor gene by intron gain.
The pancreatitis-associated protein (PAP) is a lectin-related secretory protein present in small amounts in the rat pancreas and rapidly overexpressed during the acute phase of pancreatitis. We demonstrate in this report that PAP is also expressed in rat intestine. A cDNA library from rat jejunum was probed with pancreatic PAP cDNA. The inserts of the selected recombinant clones corresponded to a transcript whose nucleotide sequence was identical to that of pancreatic PAP mRNA. The transcript was detected in duodenum, jejunum, ileum, and colon. A protein with same molecular mass (16 kDa) and pI (8.2) as pancreatic PAP was actually immunodetected in ileum homogenate after separation by two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Intestinal PAP was immunolocalized to the epithelial cells of the lower part of the villi. The protein accounted respectively for 0.02, 0.05, and 0.1% of soluble proteins in duodenum, jejunum, and ileum homogenates, as measured by enzyme-linked immunosorbent assay, and could not be detected in stomach and colon. Influence of fasting and feeding on PAP mRNA concentration was analyzed in ileum. Concentration decreased by 81 and 94% after animals were fasted for 24 and 48 h, respectively. Feeding restored the initial content within 6 h. On the other hand, intestinal PAP mRNA concentration was not altered during acute pancreatitis.
Experimental pancreatic lesions can be induced by a number of different procedures, e.g. pancreatic hyperstimulation, intraductal application of bile acids, feeding choline deficient diet, obstruction of pancreatic duct, or reducing pancreatic blood flow. The pathogenetic mechanisms leading to pancreatic lesions include basolateral enzyme secretion, acinar cell polarisation defect, intracellular activation of proteases, and the production of free radicals and other active metabolites. The importance of these individual mechanisms in the production and progression of different experimentally-induced pancreatic lesions remains speculative. These pathogenetic concepts have inspired the study of a number of substances likely to protect the pancreas and prevent the pancreatic lesions. This paper gives an overview of the pathogenetic concepts of development of and protection against experimental pancreatic lesions produced in animal models. Special mention has been made of an animal model of pancreatic lesion produced by immunosuppressives.
Rat pancreatic secretory proteins were separated by an automated liquid chromatography system utilizing a Mono S cation-exchange column. Optimal resolution was obtained with a multistep salt and pH gradient (0.01-2 M LiCl, pH 5.3-63). A total of fourteen well-separated peaks, as well as several minor peaks, were detected by UV absorption. The main pancreatic enzymes were resolved (two amylases, two chymotrypsinogens, two trypsinogens, proelastase, lipase, prophospholipase A2, procarboxypeptidase A, procarboxypeptidase B, and ribonuclease). In addition, proteins without enzymic activity, such as lithostathine and pancreatitis-associated protein, were identified. Activation of proenzymes did not occur during the separation. At a flow-rate of 0.5 ml/min, ca. 250 micrograms to 5 mg of protein could be applied with equal resolution. The reproducibility of retention volumes and peak areas was high (less than 1% or 5% variation, respectively). When radiolabeled proteins were separated, a comparable pattern of peaks was obtained. The technique described is, therefore, not only useful for analytical and preparative separation of pancreatic proteins but can additionally serve for quantitative determination of the pancreatic isoenzyme pattern.
After pancreas transplantation, signs of acute pancreatitis are found in the grafted tissue. Pancreatic juice secreted from this organ was analyzed by gel electrophoresis. Initially, the pattern of secretory proteins was similar to that of the juice collected from normal individuals, but high levels of albumin were present. Within 2 days after reperfusion of the grafted pancreas, proteins of molecular weights 17,000-20,000 increased remarkably. Separation by two-dimensional gel electrophoresis showed that this was largely due to the appearance of new a protein, present neither in the juice collected immediately after reperfusion nor in normal pancreatic juice. After transfer onto nitrocellulose, this additional protein was detected by antibodies directed against the recently described rat "pancreatitis-associated protein." Maximal amounts of approximately 7.5% of total secretory protein were found 5 days after transplantation. The concentration of the protein decreased in the further course but was still detectable after 45 days. The isoelectric point (7.1) and the molecular weight (17,500) were similar to those of the rat protein. It is concluded that after inflammation induced by pancreatic transplantation, the human pancreas secretes high amounts of a protein not present in normal juice. Because of its similarities to the rat pancreatitis-associated protein it is designated human pancreatitis-associated protein.
A human pancreatic cDNA library was screened with the cDNA encoding rat "pancreatitis-associated protein" (PAP). The selected clone encoded a secretory protein structurally related to rat PAP. The protein had the same size as rat PAP and showed 71% amino acid identity, the six half-cystines being in identical positions. Domains of the proteins showing homologies with calcium-dependent lectins were also conserved. In addition, expression in pancreas of the genes encoding the human protein and rat PAP showed similar characteristics: both were expressed at very low levels in control tissue and overexpressed during the acute phase of pancreatitis, contrary to most secretory products. The human protein was therefore named human pancreatitis-associated protein (PAP-H). Antibodies raised to a synthetic peptide of PAP-H detected a single band with an M(r) compatible with PAP-H in Western blot analysis of proteins extracted from a pancreas presenting with acute pancreatitis. In that tissue, the protein could be immunolocalized to the apical regions of acinar cells. An immunoassay was also constructed to quantify the protein in serum. Elevated PAP-H levels were observed in patients with acute pancreatitis and in some patients with chronic pancreatitis. Values were close to background in healthy subjects and in patients with other abdominal diseases. These results confirm that PAP-H synthesis increases during inflammation and suggest a possible use of the protein as biological marker of acute pancreatitis.
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Automated chromatography techniques such as high-performance (high-pressure) liquid chromatography (HPLC) or fast protein liquid chromatography (FPLC) represent a promising, new approach toward resolving the complex protein mixture of pancreatic juice. To achieve highly reproducible and rapid resolution of pancreatic protein profiles, reversed-phase, hydrophobic interaction, and ion-exchange techniques are employed. Until now, none of the respectively reported methods has provided a convenient, specific procedure for diagnostic purposes. However, experimental data prove that these methods are very sensitive and furthermore, easy to handle. Therefore, it seems possible to utilize such methods for diagnostics in future.
Rat pancreatitis-associated protein (PAP) is an additional protein appearing in pancreatic juice after induction of prancreatic inflammation. Its messenger RNA was cloned and sequenced from pancreas. The deduced amino acid sequence revealed that PAP was synthetized as a preprotein with, in its mature form, a predicted molecular weight of 16,630. A search in protein data bases revealed a marked homology with the carbohydrate binding region of animal lectins; no hemagglutination activity could be shown for PAP, but the protein induced extensive bacterial aggregation. In healthy rats, the very low level of PAP expression in pancreas could be increased up to 4-fold by physiological stimuli such as chronic hormonal or cholinergic stimulation of pancreatic secretion and adaptation of rats to a carbohydrate-rich diet. By contrast, induction of acute experimental pancreatitis by retrograde injection of sodium taurocholate resulted in dramatic overexpression. Pancreatic concentration of PAP mRNA increased more than 300 x within 12 h whereas concentrations of mRNAs encoding major secretory proteins such as amylase decreased. PAP overexpression persisted during the 2 days of the acute phase and then returned to the control level during pancreatic recovery. PAP mRNA could not be evidenced in liver, stomach, salivary glands, brain, kidney, or testis. Its pattern of expression during severe pancreatic aggression suggests that it might be a stress protein involved in the control of bacterial proliferation.
A new protein was purified from the pancreatic juice of rats with acute pancreatitis. That protein, not detectable in control animals, was called "pancreatitis-associated protein." It was first observed 6 hours after induction of experimental pancreatitis with taurocholate or cerulein, reached maximal levels of 45 micrograms/mg protein in zymogen granules and 1.8 micrograms/mg protein in pancreatic tissue during the acute phase (48 hours), and disappeared during recovery (day 5). It was never detected in spleen, liver, kidney, heart, or lung. The detection limit of the assay system was 12 ng/mg protein, so that pancreatitis-associated protein levels increased at least 100-fold in pancreatic tissue during the acute phase. The molecular weight (12,000) and isoelectric point (8.2) were determined by two-dimensional gel electrophoresis. Subcellular fractionation and immunoelectron microscopy showed that the protein was synthesized on the rough endoplasmic reticulum and stored in zymogen granules before being secreted, similar to other pancreatic secretory proteins. Immunoblotting and two-dimensional gel electrophoresis revealed that the same protein was synthesized upon induction of pancreatitis by cerulein infusion, by retrograde injection of bile acids, or pancreatitis induced by pancreatic surgery. The pancreatitis-associated protein is therefore an acute-phase protein that differs from other proteins of that family because of its exocrine nature.
We investigated pancreatic gene expression in the rat in response to taurocholate-induced acute pancreatitis. Concentrations of transcripts encoding pancreatic protein showed noncoordinated alterations. Contents in amylase, trypsinogen I, chymotrypsinogen B, elastase 1, and procarboxypeptidase A mRNAs decreased by greater than 50% during the acute phase (days 0-2), whereas actin and lithostathine mRNAs increased 5 and 0.6 times, respectively, and pancreatitis-associated protein (PAP) mRNA increased greater than 200 times, indicating redirection of the pattern of gene expression. Synthesis of pancreatic proteins was also altered in a noncoordinated manner. During the acute phase, it decreased more for trypsinogen I and chymotrypsinogen B than for amylase and lipase, whereas synthesis of the PAP increased dramatically. For amylase and chymotrypsinogen B, we compared the patterns of changes in mRNA concentrations, rates of synthesis, and pancreatic contents. Changes in enzyme contents and synthetic rates were temporally correlated during the acute phase. On the contrary, changes in mRNA concentrations and enzyme synthesis were not coordinated, suggesting that control of synthesis partly occurred at the posttranscriptional level. It was concluded that induction of pancreatitis is accompanied by transcriptional and posttranscriptional modifications resulting in rapid and massive rearrangement of the pattern of pancreatic protein gene expression.
Exocrine proteins contained in human pancreatic juice were analyzed by reversed-phase high performance liquid chromatography (RP-HPLC). Pancreatic juice was saved by endoscopic retrograde cannulation of the main pancreatic duct in 17 persons: 12 without pancreatic disease, 3 patients suffering from recurrent acute pancreatitis probably due to pancreas divisum, 1 patient with a carcinoma of the pancreas, and 1 patient with chronic calcified pancreatitis. The juice proteins were separated on a silica column (Nucleosil 300-7 RP) by use of a multistep acetonitrile/water gradient (+0.1% trifluoroacetic acid). Up to 18 individual peaks could be separated by one analytical run (60 min). Molecular weight analysis by sodium dodecyl sulfate-gel electrophoresis indicated the presence of enzymes such as amylase, prophospholipase A2, procarboxypeptidases, trypsinogens, and chymotrypsinogens in certain peaks. Small residual enzymatic activities correlating with certain peaks were detected for amylase and chymotrypsin, and high residual activities were found for phospholipase A (recovery of enzymatic activity compared with the original sample amounted to 65%). Significant amounts of cathodic trypsin-like immunoreactivity were found in two certain peaks. By always loading 350 micrograms of protein/injection on the column the profiles of various samples showed similar patterns. Repeated injections of aliquots revealed highly reproducible profiles. RP-HPLC offers precise, reproducible, and rapid separation of the major proteins of human pancreatic juice.