Although Behçet's disease (BD) is a multisystem disorder of unknown causes, both genetic and environmental factors have been suggested. This is the second reported case of monozygotic twins concordant for Behçet's disease and the first such report of intestinal Behçet's disease. Patient 1 was a 17-year-old man with fever, recurrent oral aphthae, and skin eruptions. He developed hematochezia and was given corticosteroid empirically. One month after he was discharged, he again developed oral ulcerations, fever, and hematochezia. Colonoscopy was performed again, showing aphthous ulcerations in the entire colon, and deep oval ulcers with marginal elevation around the ileocecal valve, which are characteristics of intestinal Behçet's disease. He was treated with colchicine and azathioprine in combination with salazosulfapyridine (SASP) and prednisolone (PSL) and achieved remission. Patient 2 was the twin brother of patient 1. He was admitted because of oral aphthous ulcerations, fever, pustules on his face and body, and genital ulcers. Two weeks later he developed hematochezia. Colonoscopic and barium enema findings were similar to those of his brother. SASP, PSL, colchicines, and azathioprine were also required to achieve remission. Both of the patients were diagnosed with intestinal Behçet's disease. Their monozygosity was confirmed by detailed genetic typing, and HLA-B51 was negative.
Transcription of the rat S14 gene is induced in response to increased carbohydrate metabolism in the liver. Because carbohydrate-induced changes in lipogenesis are mediated in part by changes in phosphorylation of multiple proteins, we investigated the role of protein phosphorylation on transcriptional regulation of the two carbohydrate response elements, a thyroid hormone receptor-independent carbohydrate response element and a thyroid receptor-dependent glucose response element located up-stream of the S14 gene. S14 reporter constructs were transiently transfected into rat primary hepatocytes and incubated with the protein or phosphatase inhibitor okadaic acid calyculin-A, or one of several protein kinase activators. Low dose okadaic acid blocked glucose induction from both elements without inhibiting glucose metabolism. Calyculin-A, a preferential phosphatase-1 inhibitor, only blocked the glucose response when glucose metabolism was inhibited. The protein kinase-C activator, 12-myristate 13-acetate, did not change the glucose responses, whereas the protein kinase-A activator, 8-(4-chlorophenylthio)cAMP, inhibited S14 transcription by inhibiting glucose metabolism. In contrast, the calcium ionophore A23187, a calmodulin kinase activator, mimicked the effect of low dose okadaic acid, but had no effect on glucose metabolism. We conclude that protein phosphatase-2A and calmodulin kinases may be involved in the glucose signaling pathway of the S14 gene. A similar phosphorylation step may be involved in the two distinct glucose response pathways.
The rat S14 gene provides an excellent model to examine the DNA sequences associated with carbohydrate regulation of hepatic gene transcription. We constructed internal deletions within 5 kilobases of the 5'-up-stream region and ligated these to a luciferase reporter gene. The constructs were transfected into primary hepatocytes and pancreatic HIT cells. In hepatocytes, an increase in the medium glucose concentration led to a parallel increase in endogenous mRNA S14 content and transfected luciferase reporter activity driven by 5 kilobases of the S14 promoter. Internal deletions of several sequences from -2706 to -285 each led to a decrease in glucose-stimulated activity, suggesting that multiple elements are necessary for the transcriptional response to glucose. Deletion from -1583 to -1069 nearly abolished the glucose effect in both cell types and delineated the carbohydrate response element (CHORE). The CHORE deletion was specific for glucose, because it did not alter the response to thyroid hormone, another known regulator of this gene. Although the CHORE sequence did not confer glucose activation to either a heterologous promoter or the basal S14 promoter (bases -285 to +19), a 5-fold enhanced response was observed when two copies of the CHORE were ligated to the first 2110 basepairs of the S14 promoter. The results suggest that the CHORE contains a carbohydrate regulatory element and operates as an enhancer in concert with other sequences within the S14 gene.
A 38-year-old woman with rheumatoid arthritis who developed Wegener's granulomatosis is described. Wegener's granulomatosis appeared with saddle nose, perforation in her nasal septum, and granuloma in the nasal cavity. Laboratory evaluation showed a positive rheumatoid factor and circulating immune complex. Radiographic examination revealed ankylotic changes in both wrist and elbow joints. Bilateral anosmia and other disease manifestations completely responded to treatment with oral cyclophosphamide and prednisolone.
S14 is a nuclear protein that is rapidly and synergistically induced by glucose and thyroid hormone, and the level of it's messenger RNA correlates with hepatocyte and adipocyte lipogenesis. We previously reported that the calcium ionophore A23187 markedly inhibits the carbohydrate response of the S14 gene without inhibiting glucose metabolism. Because the calcium ionophore not only increased intracellular cytosolic free calcium but also depletes intracellular calcium stores, we examined which of these two possibilities accounts for the regulation of S14 gene transcription. We found that increasing cytosolic calcium with arginine vasopressin is insufficient to inhibit S14 gene transcription. Furthermore, reduction of intracellular calcium by addition of EGTA to medium containing A23187 leads to further inhibition of S14 transcription. Measurement of intracellular free calcium in indo-1-loaded hepatocytes showed no significant changes induced by high glucose. These results suggested that depletion of an intracellular pool of calcium by A23187 causes the inhibition of S14 transcription. Addition of thapsigargin, which depletes intracellular calcium pools by inhibition of endoplasmic reticulum Ca2+-ATPase, led to significant inhibition of glucose-regulated S14 transcription. Lastly, continuous incubation in 5.5 mM glucose depletes the thapsigargin-sensitive calcium pool. These studies imply that the ability of glucose to induce S14 transcription is related to a thapsigargin-sensitive calcium pool, and depletion of this pool by lowering glucose inhibits S14 transcription.
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