Association of keratin 8 gene mutation with chronic pancreatitis.

BACKGROUND: Keratin 8 (K8) and 18 (K18) are the major components of the intermediate filament cytoskeleton of pancreatic acinar cells and play a relevant role in pancreatic exocrine homeostasis. Transgenic mice for K8 have shown to display progressive exocrine pancreas alterations, including dysplasia, loss of acinar architecture, redifferentiation of acinar to ductal cells, inflammation, fibrosis, and substitution of exocrine tissue by adipose tissue. AIM: To investigate whether mutations in the keratin 8 gene are associated with chronic pancreatitis. METHODS: Mutations in the keratin 8 gene were determined by polymerase chain reaction/restriction fragment length polymorphism in 67 chronic pancreatitis patients and 100 normal controls. Sequence analysis was performed when necessary. RESULTS: Glycine-to-cysteine mutations at position 61 (G61C) of the keratin 8 gene were found in six patients (8.9 vs. 0%, p(c) < 0.003, odds ratio = 21.24, confidence interval = 2.74-164.42); none of the controls presented the mutation. No tyrosine-to-histidine mutations at position 53 (Y53H) were detected in any subject. CONCLUSION: G61C mutation of the keratin 8 gene, together with other environmental factors and/or genetic factors, could predispose to chronic pancreatitis, by interfering with the normal organization of keratin filaments.

Natural history of pancreatitis associated with cystic fibrosis gene mutations.

BACKGROUND: An increased incidence of CFTR mutations has recently been reported in chronic and idiopathic pancreatitis. AIM: The aim of the study was to verify these data and describe the clinical, morphological and histological findings in 99 patients (59 males, 40 females, mean age 40+/-16 years), 45 suffering from idiopathic chronic pancreatitis and 54 from acute recurrent pancreatitis. METHODS: Each subject was screened for the 18 CFTR mutations: DF508, DI507, R1162X, 2183AA>G, 21303K, 3849+10KbC>T, G542X, 1717-1G>A, R553X, Q552X, G85E, 711+5G>A, 3132delTG, 2789+5G>A, W1282X, R117H, R347P, R352Q), which cover 72% of cystic fibrosis chromosomes in the Italian population, plus the 5-thymidine allele in intron 8 of the CFTR gene (IVS85T). RESULTS: Among the 99 patients, we found 14 patients with CFTR mutation (14.1%). Three idiopathic chronic pancreatitis patients had cystic fibrosis (compound mutations in two and a single mutation with a pathological sweat test in one) and 11 (11.1%) presented a single mutation (carriers) (seven idiopathic chronic pancreatitis and four acute recurrent pancreatitis). The incidence of patients with cystic fibrosis was 167.5 times higher than that observed in the general population, whereas the carrier frequency was 4.43 times higher for chronic pancreatitis and 2.11 times for acute recurrent pancreatitis than that observed in 428 unrelated partners of cystic fibrosis patients. The prevalence of IVS8-5T was similar (7.1%) to that of the general population (10%). All idiopathic chronic pancreatitis patients with one or more CFTR gene mutations had a long history of recurrent attacks of pancreatitis. The length of recurrences of pancreatitis before diagnosis of chronic pancreatitis was shorter in chronic pancreatitis patients with one or more CFTR gene mutations than in the other idiopathic chronic pancreatitis patients (7.4+/-5.8 vs. 2.1+/-2 years). In idiopathic chronic pancreatitis patients with one or more CFTR gene mutations, exocrine and endocrine insufficiency (diabetes and steatorrhoea) were rare or delayed events. CONCLUSIONS: The natural history of pancreatitis associated with CFTR gene mutations seems to be characterised by recurrences of pancreatitis which develops into chronic pancreatitis.

High serum levels of secretory immunoglobullin A in chronic pancreatitis.

BACKGROUND AND AIM: Elevated levels of secretory immunoglobulin A have been reported in patients with cholestatic hepatitis. Secretory immunoglobulin A is present in the biliary and pancreatic tract. Chronic pancreatitis is a disease characterized by dilatation of Wirsung's duct. The aim of the study was to evaluate secretory immunoglobulin A levels in patients suffering from chronic pancreatitis. PATIENTS AND METHODS: The study population consisted of 66 consecutive chronic pancreatitis patients (55 male, 11 female; mean age 49.6+/-10 years), 26 patients suffering from acute recurrent pancreatitis (9 males, 17 females; mean age 39.6+/-10.6 years) and 90 healthy controls, pair-matched for sex and age with the chronic pancreatitis patients. Secretory immunoglobulin A was determined by enzyme-linked immunosorbent assay, as were serum alanine transaminase and GGT. RESULTS: Secretory immunoglobulin A levels were significantly higher in chronic pancreatitis patients (35+/-23.7 mg/l) than in those acute recurrent pancreatitis group (16.1+/- 7.9) and in healthy controls (11.8+/-4.9 mg/l) (p<0.0001). Secretory immunoglobulin A was significantly higher in chronic pancreatitis patients with steatorrhoea, diabetes and calcifications and in those undergoing pancreatic surgery. Of 61 chronic pancreatitis patients, 14 (23%) had pathological GGT. When only chronic pancreatitis patients with normal GGT levels were analysed, the differences in secretory immunoglobulin A levels between groups of patients and between chronic pancreatitis subgroups remained statistically significant. CONCLUSIONS: This study demonstrates that secretory immunoglobulin A is elevated in chronic pancreatitis. Its value in the staging of patients needs to be further evaluated.

The Fc gamma RI receptor signals through the activation of hck and MAP kinase.

U937 cells differentiated with IFN-gamma (termed U937IF cells) were used to study Fc gamma RI signaling. IFN induces a functional Fc gamma RI receptor signaling pathway in U937 cells, leading to the activation of the respiratory burst. IFN induces the expression of the nonreceptor protein tyrosine kinase, hck, and cross-linking the Fc gamma RI receptor in U937IF cells results in the activation of hck kinase as evidenced by the three- to fivefold increased tyrosine phosphorylation of hck. In vitro kinase assays demonstrate that the specific kinase activity of hck is increased 10-fold after Fc gamma RI stimulation. hck is observed to associate with two prominent tyrosine-phosphorylated proteins, p72 and p95, after Fc gamma RI-activation. Fc gamma RI cross-linking also results in mobility shift in MAP kinase in U937IF cells, suggesting that the Fc gamma RI receptor signals through the activation of MAP kinase. The data suggest that hck, p72, p95, and MAP kinase are involved in signal transduction through the Fc gamma RI receptor.

Purification and characterization of a template-associated protein kinase that phosphorylates RNA polymerase II.

We have recently shown that a template-associated protein kinase, which phosphorylates the carboxyl-terminal domain (CTD) of RNA polymerase II, is a two-component system. We describe here the purification of these two components to apparent homogeneity from human (HeLa) cell nuclear extract. Kinase component A has a 340-kDa native molecular mass, consists of a single large polypeptide, and contains the kinase active site. Kinase component B, which is identical to the Ku autoantigen, has a 180-kDa native molecular mass, and consists of apparently equimolar 67- and 83-kDa polypeptides. Component B stimulates the activity of component A, and under some conditions, confers DNA dependence on the reaction. The purified kinase converts the CTD to the multiply phosphorylated CTD0 form. Conversion occurs processively, and this processivity is an inherent property of component A. The in vitro phosphorylated CTD0 form contains approximately equimolar phosphoserine and phosphothreonine, but no detectable phosphotyrosine.