trypsinogen and Lung-Diseases

Topics: Child; Chronic Disease; False Negative Reactions; Humans; Infant, Newborn; Lung Diseases; Neonatal Screening; Sweat; Trypsinogen

Cyclooxygenase-2 (COX-2), a widely distributed enzyme, plays an important role in inflammation. We have studied the role of COX-2 in acute pancreatitis and pancreatitis-associated lung injury using both the pharmacological inhibition of COX-2 and genetic deletion of COX-2. Pancreatitis was induced in mice by 12 hourly injections of cerulein. The severity of pancreatitis was assessed by measuring serum amylase, pancreatic trypsin activity, intrapancreatic sequestration of neutrophils, and acinar cell necrosis. The severity of lung injury was evaluated by measuring lactate dehydrogenase levels in the bronchoalveolar lavage fluid and by quantitating neutrophil sequestration in the lung. In both the pharmacologically inhibited and genetically altered mice, the severity of pancreatitis and pancreatitis-associated lung injury was reduced compared with the noninhibited strains of COX-2-sufficient mice. This reduction in injury indicates that COX-2 plays an important proinflammatory role in pancreatitis and its associated lung injury. Our findings support the concept that COX-2 inhibitors may play a beneficial role in the prevention of acute pancreatitis or in the reduction of its severity.

Topics: Animals; Celecoxib; Ceruletide; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Cyclooxygenase Inhibitors; HSP70 Heat-Shock Proteins; Isoenzymes; Lung Diseases; Mice; Mice, Inbred C57BL; Mice, Knockout; NF-kappa B; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Nitrobenzenes; Pancreatitis; Prostaglandin-Endoperoxide Synthases; Pyrazoles; RNA, Messenger; Severity of Illness Index; Sulfonamides; Trypsinogen

Extracellular cleavage of virus envelope fusion glycoproteins by host cellular proteases is a prerequisite for the infectivity of mammalian and nonpathogenic avian influenza viruses, and Sendai virus. In search of such target processing proteases in the airway, we recently found a new candidate trypsin-like processing protease in rat lungs, which was induced by Sendai virus infection, and identified as ectopic rat anionic trypsin I. On SDS/PAGE under reducing and nonreducing conditions, the purified enzyme gave protein bands corresponding to 29 and 22 kDa, respectively, i.e. at the same positions as rat pancreatic anionic trypsin I. It exhibited an apparent molecular mass of 31 kDa on molecular sieve chromatography and its isoelectric point was pH 4.7. The amino-acid sequences of the N-terminus and proteolytic digest peptides of the purified enzyme were consistent with those of rat pancreatic anionic trypsin I. Its substrate specificities and inhibitor sensitivities were the same as those of the pancreatic enzyme. The purified enzyme efficiently processed the fusion glycoprotein precursor of Sendai virus and hemagglutinin of human influenza A virus, and potentiated the infectivity of Sendai virus in the same dose-dependent manner as the pancreatic one. Immunohistochemical studies revealed that this protease is located in the stromal cells in peri-bronchiolar regions. These results suggest that ectopic anionic trypsin I in rat lungs induced by virus infection may trigger virus spread in rat lungs.

Topics: Amino Acid Sequence; Animals; Enzyme Induction; Lung; Lung Diseases; Male; Molecular Sequence Data; Pancreas; Rats; Rats, Wistar; Respirovirus Infections; Sendai virus; Sequence Homology, Amino Acid; Substrate Specificity; Trypsin; Trypsin Inhibitors; Trypsinogen

Pancreatic proteases are secreted in acute pancreatitis, but their contribution to associated lung injury is unclear. Applying models of mild edematous (intravenous caerulein) and severe necrotizing (intraductal glycodeoxycholic acid) pancreatitis in rats, we showed that both trypsinogen and trypsin concentrations in peripheral blood, as well as lung injury, correlate with the severity of the disease. To isolate the potential contribution of proteases to lung injury, trypsin or trypsinogen was injected into healthy rats or trypsinogen secreted in caerulein pancreatitis was activated by intravenous enterokinase. Pulmonary injury induced by protease infusions was dose dependent and was ameliorated by neutrophil depletion. Trypsinogen activation worsened lung injury in mild pancreatitis. In vitro incubation of leukocytes with trypsinogen showed that stimulated leukocytes can convert trypsinogen to trypsin. In conclusion, this study demonstrates that the occurrence and severity of pancreatitis-associated lung injury (PALI) corresponds to the levels of circulating trypsinogen and its activation to trypsin. Neutrophils are involved in both protease activation and development of pulmonary injury.

Topics: Acute Disease; Animals; Carcinogens; Ceruletide; Detergents; Endopeptidases; Enteropeptidase; Enzyme Activation; Enzyme-Linked Immunosorbent Assay; Glycodeoxycholic Acid; Leukocytes; Lung; Lung Diseases; Male; Oligopeptides; Pancreas; Pancreatitis; Peroxidase; Rats; Rats, Sprague-Dawley; Tetradecanoylphorbol Acetate; Trypsin; Trypsinogen