G-protein-coupled receptor (GPCR) agonists are well-known inducers of cardiac hypertrophy. We found that the shedding of heparin-binding epidermal growth factor (HB-EGF) resulting from metalloproteinase activation and subsequent transactivation of the epidermal growth factor receptor occurred when cardiomyocytes were stimulated by GPCR agonists, leading to cardiac hypertrophy. A new inhibitor of HB-EGF shedding, KB-R7785, blocked this signaling. We cloned a disintegrin and metalloprotease 12 (ADAM12) as a specific enzyme to shed HB-EGF in the heart and found that dominant-negative expression of ADAM12 abrogated this signaling. KB-R7785 bound directly to ADAM12, suggesting that inhibition of ADAM12 blocked the shedding of HB-EGF. In mice with cardiac hypertrophy, KB-R7785 inhibited the shedding of HB-EGF and attenuated hypertrophic changes. These data suggest that shedding of HB-EGF by ADAM12 plays an important role in cardiac hypertrophy, and that inhibition of HB-EGF shedding could be a potent therapeutic strategy for cardiac hypertrophy.

In many species the pancreatic duct epithelium secretes HCO3- ions at a concentration of around 140 mM by a mechanism that is only partially understood. We know that HCO3- uptake at the basolateral membrane is achieved by Na+-HCO3- cotransport and also by a H+-ATPase and Na+/H+ exchanger operating together with carbonic anhydrase. At the apical membrane, the secretion of moderate concentrations of HCO3- can be explained by the parallel activity of a Cl-/HCO3- exchanger and a Cl- conductance, either the cystic fibrosis transmembrane conductance regulator (CFTR) or a Ca2+-activated Cl- channel (CaCC). However, the sustained secretion of HCO3- into a HCO- -rich luminal fluid cannot be explained by conventional Cl-/HCO3- exchange. HCO3- efflux across the apical membrane is an electrogenic process that is facilitated by the depletion of intracellular Cl-, but it remains to be seen whether it is mediated predominantly by CFTR or by an electrogenic SLC26 anion exchanger.

At least eight inherited neurodegenerative diseases are caused by expanded CAG repeats encoding polyglutamine (polyQ) stretches. Although cytotoxicities of expanded polyQ stretches are implicated, the molecular mechanisms of neurodegeneration remain unclear. We found that expanded polyQ stretches preferentially bind to TAFII130, a coactivator involved in cAMP-responsive element binding protein (CREB)-dependent transcriptional activation, and strongly suppress CREB-dependent transcriptional activation. The suppression of CREB-dependent transcription and the cell death induced by polyQ stretches were restored by the co-expression of TAFII130. Our results indicate that interference of transcription by the binding of TAFII130 with expanded polyQ stretches is involved in the pathogenetic mechanisms underlying neurodegeneration.

1. Short segments of interlobular duct were microdissected from guinea-pig pancreas following enzymatic digestion. After overnight culture, intracellular pH (pH1) and Na+ concentration ([Na+]1) were measured by microfluorometry in duct cells loaded with either the pH-sensitive fluoroprobe 2'7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF) or the sodium-binding benzofuran isophthalate (SBFI).2. The transporters responsible for maintaining pHi above equilibrium were investigated by using the NH4C1 pulse technique to acid load the cells. In the absence of HCO3-/CO2, the recovery of pHi was Na+ dependent, abolished by 0-2 mm amiloride and by 10 am N-methyl-N-isobutylamiloride and was therefore attributed to Na+-H+ exchange.3. In the presence of HC03-/CO2, amiloride only partially inhibited the recovery from acid loading. The amiloride-insensitive component was abolished by 0 5 mm H2DIDS and unaffected by depletion of intracellular Cl-and was therefore attributed to Na+-HCO03 cotransport.4. Stimulation with 10 nm secretin did not cause a significant change in pHi despite a significant increase in HC03-efflux. However, in the presence of secretin, addition of 0 5 mm H2DIDS caused a decline in pHi that was three times more rapid than that obtained with 0-2 mm amiloride.5. In secretin-stimulated ducts, Na+ uptake increased when HC03-/CO2 was added to the bath and this increase was strongly inhibited by 0.5 mm H2DIDS. 6. We conclude that Na+-HCO -cotransport contributes approximately 75% of the HC03-taken up by guinea-pig pancreatic duct cells during stimulation with secretin. It is proposed that electrical coupling between HC03-efflux at the luminal membrane and electrogenic

Indoleamine 2,3-dioxygenase (IDO) is induced by interferon (IFN)-gamma-mediated effects of the signal transducer and activator of transcription 1alpha (STAT1alpha) and interferon regulatory factor (IRF)-1. The induction of IDO can also be mediated through an IFN-gamma-independent mechanism, although the mechanism of induction has not been identified. In this study, we explored whether lipopolysaccharide (LPS) or several proinflammatory cytokines can induce IDO via an IFN-gamma-independent mechanism, and whether IDO induction by LPS requires the STAT1alpha and IRF-1 signaling pathways. IDO was induced by LPS or IFN-gamma in peripheral blood mononuclear cells and THP-1 cells, and a synergistic IDO induction occurred when THP-1 cells were cultured in the presence of a combination of tumor necrosis factor-alpha, interleukin-6 or interleukin-1beta. An electrophoretic mobility shift assay using STAT1alpha and IRF-1 consensus oligonucleotide probes showed no STAT1alpha or IRF-1 binding activities in LPS-stimulated THP-1 cells. Further, the LPS-induced IDO activity was inhibited by both p38 mitogen-activated protein kinase (MAPK) and nuclear factor-kappaB (NF-kappaB) inhibitors. These findings suggest that the induction of IDO by LPS in THP-1 cells is not regulated by IFN-gamma via recruitment of STAT1alpha or IRF-1 to the intracellular signaling pathway, and may be related to the activity of the p38 MAPK pathway and NF-kappaB.

1. Pancreatic HCOצ and fluid secretion were studied by monitoring luminal pH (pHL) and luminal volume simultaneously in interlobular duct segments isolated from guinea-pig pancreas. The secretory rate and HCOצ flux were estimated from fluorescence images obtained following microinjection of BCECF-dextran (70 kDa, 20 ìÒ) into the duct lumen. 2. Ducts filled initially with a Cl¦-rich solution swelled steadily (2·0 nl min¢ mm¦Â) when HCOצÏCOµ was introduced, and the luminal pH increased to 8·08. When Cl¦ was replaced by glucuronate, spontaneous fluid secretion was reduced by 75%, and pHL did not rise above 7·3. 3. Cl¦-dependent spontaneous secretion was largely blocked by luminal HµDIDS (500 ìÒ). We conclude that, in unstimulated ducts, HCOצ transport across the luminal membrane is probably mediated by Cl¦-HCOצ exchange. 4. Secretin (10 nÒ) and forskolin (1 ìÒ) both stimulated HCOצ and fluid secretion. The final value of pHL (8·4) and the increase in secretory rate (1·5 nl min¢ mm¦Â) after secretin stimulation were unaffected by substitution of Cl¦. 5. The Cl¦-independent component of secretin-evoked secretion was not affected by luminalHµDIDS. This suggests that a Cl¦-independent mechanism provides the main pathway for luminal HCOצ transport in secretin-stimulated ducts. 6. Ducts filled initially with a HCOצ-rich fluid (125 mÒ HCOצ, 23 mÒ Cl¦) secreted a Cl¦-rich fluid while unstimulated. This became HCOצ-rich when secretin was applied. 7. Addition of HµDIDS and MIA (10 ìÒ) to the bath reduced the secretory rate by 56 and 18%, respectively. Applied together they completely blocked fluid secretion. We conclude that basolateral HCOצ transport is mediated mainly by Na¤-HCOצ cotransport rather than by Na¤-H¤ exchange.7803

Chronic pancreatitis is considered to be an irreversible progressive chronic inflammatory disease. The etiology and pathology of chronic pancreatitis are complex; therefore, it is important to correctly understand the stage and pathology and provide appropriate treatment accordingly. The newly revised Clinical Practice Guidelines of Chronic Pancreatitis 2015 consist of four chapters, i.e., diagnosis, staging, treatment, and prognosis, and includes a total of 65 clinical questions. These guidelines have aimed at providing certain directions and clinically practical contents for the management of chronic pancreatitis, preferentially adopting clinically useful articles. These revised guidelines also refer to early chronic pancreatitis based on the Criteria for the Diagnosis of Chronic Pancreatitis 2009. They include such items as health insurance coverage of high-titer lipase preparations and extracorporeal shock wave lithotripsy, new antidiabetic drugs, and the definition of and treatment approach to pancreatic pseudocyst. The accuracy of these guidelines has been improved by examining and adopting new evidence obtained after the publication of the first edition.

Manchester M13 9PT, UK 1. The transport of HC03-across the luminal membrane of pancreatic duct cells was studied by monitoring the luminal pH of isolated guinea-pig interlobular ducts after microinjection of an extracellular fluoroprobe, the dextran conjugate of 2'7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF-dextran). Luminal Cl-concentration was also measured by microfluorometry following microinjection of the dextran conjugates of 6-methoxy-N-(4-aminoalkyl)quinolinium bromide (ABQ-dextran) and Cl-NERF (Cl-NERF-dextran).2. When HC03-/C02 was admitted to the bath, a transient acidification of the duct lumen was observed, followed by a marked alkalinization. The latter was abolished when the luminal CF-concentration was reduced to 25-35 mm by replacement with glucuronate and may, therefore, be attributed to Cl--HC03-exchange at the luminal membrane.3. Secretin, forskolin and acetylcholine stimulated HC03-secretion into the lumen even when the luminal Cl-concentration was reduced to approximately 7 mm. Furthermore, agonistevoked HC03-secretion was not inhibited by luminal glibenclamide, dihydro-4,4'-diisothiocyanostilbene-2,2'-disulphonic acid (H2DIDS) or 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB). These observations are not easily reconciled with HC03-transport across the luminal membrane being mediated by Cl--HC03-exchange in parallel with a Clconductance.4. Agonist-stimulated HC03-secretion was blocked by omitting Nae from the bath but not by addition of N-methyl-N-isobutylamiloride (MIA) or bafilomycin A1. This supports our previous conclusion that HC03-entry into duct cells from the extracellular fluid requires Nae but is not dependent on Na+-H+ exchange or vacuolar-type H+-ATPase activity. 5. The three actions of secretin on guinea-pig pancreatic duct cells described in this and the accompanying paper -stimulation of a relatively Cl--insensitive luminal HC03-efflux pathway, stimulation of basolateral Nae-HC03-cotransport, and lack of effect on intracellular pH -require the current model of pancreatic HC03-secretion to be modified.