Hydrodissection During Computed Tomography-Guided Cryoablation for Renal Tumors: Where is the Effective Fluid Accumulation Space in the Retroperitoneum?

PURPOSE: This study was performed to investigate the effectiveness of hydrodissection during computed tomography-guided renal cryoablation by evaluation of the fluid distribution based on the retroperitoneal anatomy with the interfascial plane. MATERIALS AND METHODS: Between March 2014 and March 2021, 52 renal tumors were treated by cryoablation with hydrodissection (36 men; mean age 72.5 years). The hydrodissection needle was located in perirenal space. The spreading fluid space based on the retroperitoneal anatomy with the interfascial plane was retrospectively evaluated. The fluid space that most effectively separated the tumor from the adjacent organs was defined. The relationship of the needle tip position in the perirenal space (renal capsule or fascia side) and the most effective fluid space was also evaluated. RESULTS: Cryoablation was successfully completed in all cases with no major complications. Hydrodissection was effective in all cases. The distance between the tumors and the adjacent organs was significantly longer after hydrodissection (from 7.50 ± 7.43 to 22.6 ± 9.86 mm) (P < 0.0001). Although fluid spreading through multiple retroperitoneal spaces was frequently observed, the retromesenteric plane was observed more frequently as the most effective fluid space (67.3%) than the perirenal space (21.2%) (P < 0.0001). Regardless of the needle tip position, the most effective fluid space was also commonly the retromesenteric plane. CONCLUSIONS: The retromesenteric plane could be the most effective fluid space to separate the tumor from the adjacent organ, regardless of where the hydrodissection needle tip is positioned in the perirenal space. LEVEL OF EVIDENCE: 3b.

CT-Guided Femoral Approach for Psoas Muscle Abscess Drainage.

PURPOSE: To evaluate the feasibility and safety of the computed tomography (CT)-guided femoral approach for draining a psoas muscle abscess (PMA). MATERIALS AND METHODS: Between January 2014 and November 2018, the CT-guided femoral approach was employed for 9 abscesses in 8 patients who could not tolerate the prone position because of advanced age or other underlying conditions. A 17-gauge blunt metal needle was used to puncture the iliacus muscle below the groin under CT fluoroscopic guidance. A drainage catheter was then placed within the abscess cavity in the psoas major muscle. Technical success, clinical success, complications, the drainage therapy duration, susceptibility to antibiotics, survival, and recurrence were evaluated. RESULTS: The technical success rate was 100% among all nine lesions. The clinical success rate was 89% among all eight patients. One patient died of concomitant meningitis 15 days after the procedure. No patients developed therapy-related complications. The median duration of the drainage therapy was 15 days (range 6-71 days). Appropriate antibiotics based on the culture susceptibility were achieved in all patients. Four patients survived, and the remaining four died at 15 to 758 days (median, 36 days) after the procedure; no therapy-related deaths occurred. No recurrence was seen. CONCLUSION: The CT-guided femoral approach seems feasible, effective, and safe for draining psoas muscle abscesses in ill patients who cannot tolerate the prone position.

A Simple Method to Avoid Bile Duct Injury during Percutaneous Radiofrequency Ablation Therapy for Hepatocellular Carcinoma.

Hepatocellular carcinoma represents a major global health burden. Its treatment is often complicated by the anatomical location of tumors, which can lead to adverse outcomes. Radiofrequency ablation has recently gained attention as a safe method for treating hepatocellular carcinoma, but only in tumors that are not adjacent to bile ducts. Here, we report a new method for cooling the bile duct during radiofrequency ablation therapy, in which the outer jacket of an elastor needle was fixed and flash-cooled with chilled saline. This method was applied in a patient with hepatocellular carcinoma tumors near the main bile duct. The patient underwent successful radiofrequency ablation with bile duct cooling. The advantages of this method include low medical cost, simpler securing of nonexpanded bile ducts, and simultaneous removal upon termination of the radiofrequency ablation therapy. Bile duct complications associated with radiofrequency ablation typically have delayed onset. Computed tomography examination 2 months after treatment showed no bile duct injury in this case.

Correction to: Reply to the letter: N-Butyl Cyanoacrylate-Lipiodol Mixture for Endovascular Purpose: Polymerization Kinetics Differences Between In Vitro and In Vivo Experiments.

We would like to correct one of the references that was listed incorrectly in our article.

Procedure of Direct Hepatic Artery Puncture for the Treatment of Hepatocellular Carcinoma: Two Case Reports.

Recently, treatment options for hepatocellular carcinoma (HCC) have expanded due to the development of the tyrosine kinase inhibitor ramucirumab and immune checkpoint inhibitors. Transcatheter arterial chemoembolization is the standard therapy for intermediate-stage HCC; however, in cases with anatomical problems, normal approaches are not possible. In such rare cases, direct hepatic puncture may be considered as an effective therapy and an indispensable treatment. We report our novel method of direct hepatic artery puncture in this case report. In 2011 and 2017, we reported 2 cases in the journal of the Japan Society of Hepatology in Japanese. This therapy is difficult and is associated with a high risk of complications; however, we succeeded in both cases in a similar way. We believe this method may provide an alternative treatment when standard treatment is not possible or when urgent therapy is required. In case 1, direct hepatic artery puncture was performed under ultrasonographic guidance, and we were able to control the disease with percutaneous lipiodol chemotherapy. Case 2 was an emergency case of ruptured HCC. Direct hepatic puncture successfully stopped tumor bleeding; furthermore, tumor necrosis also occurred, as seen on the enhanced computed tomography image. Our new method requires advanced puncture techniques and is not the treatment of choice if there are other safe alternatives available. However, it can be considered as an option if there are no other viable, effective treatments.

Is the Cessation of Blood Flow Faster than the Polymerization of an n-Butyl Cyanoacrylate-Lipiodol Mixture? An In Vitro Phantom Study.

PURPOSE: To compare the polymerization time of n-butyl cyanoacrylate (NBCA) and lipiodol mixture in a static model and a pulsating flow model simulating embolization procedure of small caliber arteries. MATERIALS AND METHODS: The polymerization time of NBCA-lipiodol mixture was measured by the morphological changes of a glue droplet in a petri dish. For the flow model, we used a 2-mm-inner-diameter polyvinyl alcohol tube connected to a pulsation pump. Bovine serum was supplied from the pump and circulated into the system at 30 ml/min and 60 bpm. A 0.64-mm-inner-diameter silicon microcatheter was inserted into this system, and then, 0.5 ml of glue was injected into the tube. The flow cessation time was defined as the time it took to stop the serum draining from the end of the tube. Six samples of 100, 66, 50, 40, 33, and 20 vol% NBCA were assessed. RESULTS: The median polymerization times for each concentration were 0.12, 3.72, 12.30, 27.41, 57.68, and 63.67 s, respectively. The median flow cessation times were 0.28, 0.78, 1.43, 3.75, 4.50, and 9.29 s, respectively. The flow cessation time was significantly shorter than the polymerization time for all samples except for 100 vol% cyanoacrylate (p < 0.05). CONCLUSION: The flow cessation time of cyanoacrylate glue was significantly shorter than the polymerization time in an in vitro experiment. The injected glue possibly stops the blood flow before the completion of polymerization in the vascular system.

Comparison of Pain Within 24 h after Uterine Artery Embolization with Tris-Acryl Gelatin Microspheres Versus Gelatin Sponge Particles for Leiomyoma.

PURPOSE: To compare acute pain after uterine artery embolization (UAE) with tris-acryl gelatin microspheres (TAGM) versus gelatin sponge particles (GS) for leiomyoma. MATERIALS AND METHODS: This was a single-institution, retrospective study. Between July 2008 and November 2016, 101 consecutive patients with symptomatic uterine leiomyoma underwent UAE with the same protocol for post-procedural pain. GS was employed with near-stasis endpoint for the first 49 patients, whereas TAGM was used with limited endpoint for the next 52 patients. Post-UAE pain levels were compared between both groups with a linear mixed model using visual analog scale (VAS) scores from 0 to 18 h as a repeat measure outcome. Peak VAS < 24 h or dose of drugs for analgesia and conscious sedation was compared by analysis of variance. Tumor infarction was assessed with post-procedural contrast-enhanced MRI. RESULTS: Baseline demographics and most outcomes including tumor infarction were similar between both groups. The average VAS scores during the period <24 h were significantly lower in TAGM group (1.68, 95% CI 1.23-2.13) compared to GS group (3.28, 95% CI 2.82-3.74, p < 0.0001). The difference remained significant even after adjustment for other factors (p < 0.0001). The mean peak VAS < 24 h was also lower in TAGM group (3.89, 95% CI 3.25-4.53) than in GS group (5.90, 95% CI 5.20-6.53, p < 0.0001). The dose of drugs for analgesia and conscious sedation was significantly lower in TAGM group (p = 0.001, p = 0.004, respectively). CONCLUSION: TAGM had an advantage over GS in UAE for leiomyoma in terms of less post-procedural pain <24 h, with lower doses of drugs for analgesia and conscious sedation.

Balloon Blocking Technique (BBT) for Superselective Catheterization of Inaccessible Arteries with Conventional and Modified Techniques.

PURPOSE: The purpose of the study was to retrospectively evaluate the efficacy and safety of the balloon blocking technique (BBT). MATERIALS AND METHODS: The BBT was performed in six patients (all males, mean 73.5 years) in whom superselective catheterization for transcatheter arterial embolization by the conventional microcatheter techniques had failed due to anatomical difficulty, including targeted arteries originating steeply or hooked from parent arteries. All BBT procedures were performed using Seldinger's transfemoral method. Occlusive balloons were deployed and inflated at the distal side of the target artery branching site in the parent artery via transfemoral access. A microcatheter was delivered from a 5-F catheter via another femoral access and was advanced over the microguidewire into the target artery, under balloon blockage of advancement of the microguidewire into non-target branches. After the balloon catheter was deflated and withdrawn, optimal interventions were performed through the microcatheter. RESULTS: After success of accessing the targeted artery by BBT, optimal interventions were accomplished in all patients with no complications other than vasovagal hypotension, which responded to nominal therapy. CONCLUSION: The BBT may be useful in superselective catheterization of inaccessible arteries due to anatomical difficulties.

Serpin B1 protects colonic epithelial cell via blockage of neutrophil elastase activity and its expression is enhanced in patients with ulcerative colitis.

Serpin B1 is a monocyte neutrophil elastase (NE) inhibitor and is one of the most efficient inhibitors of NE. In the present study, we investigated the role of serpin B1 in the pathogenesis of ulcerative colitis by using clinical samples and an experimental model. The colonic expression of serpin B1 was determined by real-time polymerase chain reaction (PCR), Western blot analysis, and immunohistological studies in both normal and inflamed mucosa from patients with ulcerative colitis. Serpin B1 mRNA expression was determined by real-time PCR in the mouse dextran sodium sulfate (DSS)-induced colitis model. Young adult mouse colonic epithelial (YAMC) cells were used to determine the role of serpin B1. Serpin B1 gene transfected YAMC cells were treated with H(2)O(2) to measure cell viability. The expression of NE was determined in YAMC cells treated with H(2)O(2). NE-silenced YAMC cells were also treated with H(2)O(2) and then measured for viability. Upregulated expression of serpin B1 in colonic mucosa was confirmed from patients with active ulcerative colitis. Immunohistochemical studies showed that serpin B1 expression was localized not only in inflammatory infiltration cells but also in epithelial cells. Serpin B1 mRNA expression was also increased in colonic mucosa of mouse DSS-induced colitis. Serpin B1-transfected YAMC cells were resistant against the treatment of H(2)O(2). H(2)O(2) treatment significantly induced NE in YAMC cells, and NE-silenced YAMC cells were also resistant against the treatment of H(2)O(2). These results suggest that serpin B1 may be a novel marker of active ulcerative colitis and may play an important role in the pathogenesis of inflammatory bowel disease.

Heat shock protein 70-dependent protective effect of polaprezinc on acetylsalicylic acid-induced apoptosis of rat intestinal epithelial cells.

Protection of the small intestine from mucosal injury induced by nonsteroidal anti-inflammatory drugs including acetylsalicylic acid is a critical issue in the field of gastroenterology. Polaprezinc an anti-ulcer drug, consisting of zinc and L-carnosine, provides gastric mucosal protection against various irritants. In this study, we investigated the protective effect of polaprezinc on acetylsalicylic acid-induced apoptosis of the RIE1 rat intestinal epithelial cell line. Confluent rat intestinal epithelial cells were incubated with 70 µM polaprezinc for 24 h, and then stimulated with or without 15 mM acetylsalicylic acid for a further 15 h. Subsequent cellular viability was quantified by fluorometric assay based on cell lysis and staining. Acetylsalicylic acid-induced cell death was also qualified by fluorescent microscopy of Hoechst33342 and propidium iodide. Heat shock proteins 70 protein expression after adding polaprezinc or acetylsalicylic acid was assessed by western blotting. To investigate the role of Heat shock protein 70, Heat shock protein 70-specific small interfering RNA was applied. Cell viability was quantified by fluorometric assay based on cell lysis and staining and apoptosis was analyzed by fluorescence-activated cell sorting. We found that acetylsalicylic acid significantly induced apoptosis of rat intestinal epithelial cells in a dose- and time-dependent manner. Polaprezinc significantly suppressed acetylsalicylic acid-induced apoptosis of rat intestinal epithelial cells at its late phase. At the same time, polaprezinc increased Heat shock protein 70 expressions of rat intestinal epithelial cells in a time-dependent manner. However, in Heat shock protein 70-silenced rat intestinal epithelial cells, polaprezinc could not suppress acetylsalicylic acid -induced apoptosis at its late phase. We conclude that polaprezinc-increased Heat shock protein 70 expression might be an important mechanism by which polaprezinc suppresses acetylsalicylic acid-induced small intestinal apoptosis, a hallmark of acetylsalicylic acid-induced enteropathy.

Daikenchuto, a Kampo medicine, regulates intestinal fibrosis associated with decreasing expression of heat shock protein 47 and collagen content in a rat colitis model.

Heat shock protein (HSP) 47 may play an important role in the pathogenesis of intestinal fibrosis. Daikenchuto (DKT), a traditional Japanese herbal (Kampo) medicine, has been reported to ameliorate intestinal inflammation. The aims of this study were to determine time-course profiles of several parameters of fibrosis in a rat model, to confirm the HSP47-expressing cells in the colon, and finally to evaluate DKT's effects on intestinal fibrosis. Colitis was induced in male Wistar rats weighing 200 g using an enema of trinitrobenzene sulfonic acid (TNBS). HSP47 localization was determined by immunohistochemistry. Colonic inflammation and fibrosis were assessed by macroscopic, histological, morphometric, and immunohistochemical analyses. Colonic mRNA expression of transforming growth factor ß1 (TGF-ß1), HSP47, and collagen type I were assessed by real time-polymerase chain reaction (PCR). DKT was administered orally once a day from 8 to 14 d after TNBS administration. The colon was removed on the 15th day. HSP47 immunoreactivity was coexpressed with α-smooth muscle actin-positive cells located in the subepithelial space. Intracolonic administration of TNBS resulted in grossly visible ulcers. Colonic inflammation persisted for 6 weeks, and fibrosis persisted for 4 weeks after cessation of TNBS treatment. The expression levels of mRNA and proteins for TGF-ß1, HSP47, and collagen I were elevated in colonic mucosa treated with TNBS. These fibrosis markers indicated that DKT treatment significantly inhibited TNBS-induced fibrosis. These findings suggest that DKT reduces intestinal fibrosis associated with decreasing expression of HSP47 and collagen content in the intestine.

FGF19 protects colonic epithelial cells against hydrogen peroxide.

BACKGROUND/AIMS: The apoptosis induced by hydrogen peroxide (H2O2) in colonic epithelial cells is very important for the pathogenesis of inflammatory bowel disease (IBD). Fibroblast growth factor (FGF) 15, the human ortholog of FGF19, is reported to be secreted from colonic myofibroblasts and enhances colonic epithelial restitution, but little is known about the function of FGF19 to colonic epithelial cells. In the present study, we investigate the anti-apoptosis effect of FGF19 in colonic epithelial cells treated with H2O2. METHODS: Young adult mouse colonic epithelial (YAMC) cells are used to investigate the protective role of FGF19. Cellular viability was determined by WST-8 assay, and apoptosis was measured by Hoechst staining and Western blotting of cleaved caspase-3. YAMC cells were pretreated by FGF19 and H2O2 was used for cellular damage. RESULTS: We demonstrated that pretreatment of FGF19 (50 ng/ml) significantly protects YAMC cells treated with H2O2 assessed by WST-8. We also demonstrated Hoechst staining of YAMC cells and that H2O2-induced apoptosis is significantly reduced by FGF19 treatment via inhibition of the caspase-3 pathway. CONCLUSION: These results indicate FGF19 protects YAMC cells against H2O2 and might be related to the pathogenesis of IBD. Even further studies are needed - FGF19 may be one of the possible therapeutic strategies of IBD.

Carbon monoxide liberated from carbon monoxide-releasing molecule exerts an anti-inflammatory effect on dextran sulfate sodium-induced colitis in mice.

BACKGROUND: Endogenous carbon monoxide (CO) is one of the three products of heme degradation by heme oxygenase-1 (HO-1) and exerts novel anti-inflammatory and anti-apoptotic effects as a gaseous second messenger. The purpose of this investigation was to determine whether exogenous CO could modulate intestinal inflammation. METHODS: Acute colitis was induced with 2% DSS in male C57BL/6 mice. CO-releasing molecule-2 (CORM-2; tricarbonyldichlororuthenium(II) dimer) was intraperitoneally administered twice daily and the disease activity index (DAI) was determined. We measured tissue-associated myeloperoxidase (MPO) activity as an index of neutrophil infiltration, and the production of keratinocyte chemoattractant (KC) and tumor necrosis factor-α (TNF-α) protein in the intestinal mucosa. In an in-vitro study, young adult mouse colonic epithelial (YAMC) cells were incubated with TNF-α, and KC mRNA/protein expression and nuclear translocation of nuclear factor-kappa B (NF-κB) were measured with or without CORM-2 treatment. RESULTS: After DSS administration, DAI score increased in a time-dependent manner, and this increase was ameliorated by CORM-2 treatment. Increases in MPO activity and in the production of KC and TNF-α after DSS administration were significantly inhibited by CORM-2. TNF-α-induced KC production in YAMC cells was also inhibited by CORM-2 treatment. Further, nuclear translocation of NF-κB in YAMC cells was inhibited by CORM-2. CONCLUSION: CORM-liberated CO significantly inhibited inflammatory response in murine colitis by inhibition of cytokine production in the colonic epithelium. These results suggest that CO could become a new therapeutic molecule for inflammatory bowel disease.

Reactive oxygen species-quenching and anti-apoptotic effect of polaprezinc on indomethacin-induced small intestinal epithelial cell injury.

BACKGROUND: To protect the small intestine from mucosal injury induced by nonsteroidal anti-inflammatory drugs is one of the critical issues in the field of gastroenterology. Polaprezinc (PZ), a gastric muco-protecting agent, has been widely used for the treatment of gastric ulcer and gastritis for its unique effects, such as its strong reactive oxygen species (ROS)-quenching effect. The aim of this study was to clarify the mechanism by which indomethacin-induced small intestinal mucosal injury occurs, by using a rat intestinal epithelial cell line (RIE-1). In addition, the protective role of PZ and the possible mechanism of its effect on indomethacin-induced small intestinal injury were investigated. METHODS: Cell death was evaluated by methyl thiazolyl tetrazolium (MTT) assay and a double-staining method with Hoechst33342 dye and propidium iodide. Indomethacin-induced ROS production was evaluated by detecting the oxidation of a redox-sensitive fluorogenic probe, RedoxSensor, and the oxidation of cysteine residues of proteins (protein S oxidation). The activation of cytochrome c, smac/DIABLO, and caspase-3 was assessed by western blotting. In some experiments, PZ or its components, L: -carnosine and zinc, were used. RESULTS: We found that indomethacin caused apoptosis in RIE-1 cells in a dose- and time-dependent manner. Indomethacin also induced ROS production and an increase in the protein S oxidation of RIE-1. Pretreatment of RIE-1 with PZ or zinc sulfate, but not L: -carnosine, significantly reduced the indomethacin-induced apoptosis. PZ prevented ROS production and the increase in protein S-oxidation. PZ inhibited indomethacin-induced cytochrome c and smac/DIABLO release and subsequent caspase-3 activation. CONCLUSIONS: The protective effect of PZ on indomethacin-induced small intestinal injury may be dependent on its ROS-quenching effect.

Carbon monoxide enhance colonic epithelial restitution via FGF15 derived from colonic myofibroblasts.

Carbon monoxide (CO) has been reported to ameliorate colonic inflammation and improve experimental colitis. It is well known that mucosal restitution is important to improve colitis as well as reduction of mucosal inflammation. However, it has not been clear whether CO effects to colonic mucosal restitution or not. In general, colonic myofibroblast (MF) has been reported to play an important role of colonic epithelial cell restitution via constitutive secretion of TGF-beta. In this study, we showed CO (supplied by CO-releasing molecule; CORM) treated MF conditioned medium enhanced colonic epithelial cell (YAMC) restitution and we determined gene expression in colonic MF treated with CO using microRNA. The microRNA array suggested that miR-710 was significantly reduced in MF by CO treatment and the target gene of miR-710 is determined to fibroblast growth factor (FGF)15. The CO treated MF conditioned medium which FGF15 expression was silenced extinguished the enhancement effect of epithelial cell restitution. Our findings demonstrate that CO treatment to MF increased FGF15 expression via inhibition of miR-710 and FGF15 enhanced colonic epithelial cell restitution.

Heat-shock protein 70-overexpressing gastric epithelial cells are resistant to indomethacin-induced apoptosis.

BACKGROUND/AIMS: Protecting intestinal mucosa from nonsteroidal anti-inflammatory drugs is still an unsolved problem. It has been revealed that apoptosis in epithelial cells as a result of mitochondrial injury is an important pathogenesis in indomethacin-induced gastric mucosal injury. In this study, we revealed the effect of overexpressed heat-shock protein 70 (HSP70) in indomethacin-induced apoptosis and oxidative stress. METHODS: HSP70-overexpressing rat gastric mucosal cells (7018-RGM-1 cells) and control cells (pBK-CMV-12 cells) were used and treated with 0-500 microM of indomethacin for 24 h. Cell viability and cytotoxity were measured by a WST-8 assay and a lactate dehydrogenase release assay, respectively. Apoptosis was observed by fluorescence microscopy staining with Hoechst 33342 and propidium iodide. The expression of Bcl-2 family proteins, activation of caspase-3, and 4-hydroxy-2-nonenal (4-HNE)-modified proteins were assessed by Western blot analysis. RESULTS: Indomethacin caused apoptosis of gastric epithelial cells. The 7018-RGM-1 cells survived significantly after indomethacin treatment compared to the control cells. The increase in pro-apoptotic Bad proteins, the decrease in anti-apoptotic Bcl-2 proteins, and caspase activation were all suppressed in the 7018-RGM-1 cells. A lower level of indomethacin-induced 4-HNE-modification was detected in the 7018-RGM-1 cells than in the control cells. CONCLUSION: Overexpressed HSP70 may potentiate resistance to apoptosis and oxidative stress in indomethacin-induced gastric epithelial cell injury.

Involvement of reactive oxygen species in indomethacin-induced apoptosis of small intestinal epithelial cells.

BACKGROUND: The precise pathogenic mechanism of nonsteroidal antiinflammatory drug-induced small intestinal injury is still unknown. In the present study, we investigated the mechanism by which indomethacin induced mucosal injury by using an in vitro model of small intestine. METHODS: The colon cancer cell line Caco-2, exhibiting a small intestinal phenotype starting as a crypt cell and differentiating to a villous phenotype, and RIE, a rat intestinal epithelial cell line, were employed. Indomethacin was added to differentiated the Caco-2 and RIE monolayer, and cell death was quantified by MTT assay and LDH release in the cell culture supernatant. Indomethacin-induced cell death was also qualified by fluorescent probes under the fluorescent microscope. As a functional study, the permeability of the Caco-2 monolayer was assessed by measuring transepithelial electrical resistance (TEER) and the flux of FITC-conjugated dextran across the monolayer. Indomethacin-induced reactive oxygen species production in Caco-2 and RIE was evaluated by redoxsensitive fluorogenic probes using a fluorometer. In some experiments, antioxidants were used to clarify the role of reactive oxygen species on indomethacin-induced Caco-2 cell death. RESULTS: Indomethacin caused cell death (mainly apoptosis) of Caco-2 and RIE in a dose-and time-dependent manner that was correlated with increased permeability of the Caco-2 monolayer. Exposure of Caco-2 and RIE with indomethacin also resulted in a significant reactive oxygen species production that was inhibited by the pretreatment of these cells with antioxidants. CONCLUSIONS: Taken together, reactive oxygen species production is one of the mechanisms by which indomethacin induced small intestinal injury.

Cooperative regulation of Fc receptor gamma-chain gene expression by multiple transcription factors, including Sp1, GABP, and Elf-1.

The Fc receptor gamma-chain (FcRgamma), which was first identified as a constituent of the high affinity IgE receptor, associates with various cell surface receptors to mediate intracellular signals. We identified three transcriptional enhancer elements in the 5' region of the human FcRgamma gene; one of the cis-elements was recognized by the transcription factor Sp-1 and another was recognized by GABP or Elf-1. The sequence of the other element was similar to a binding motif of the C/EBP family. Overexpression experiments showed that these transcription factors cooperatively activated the FcRgamma promoter. Furthermore, inactivation of the GABP-binding site by nucleotide substitutions as well as repression of GABPalpha expression by RNA interference reduced Sp1-mediated transactivation of the FcRgamma promoter, demonstrating that Sp1 and GABP synergistically activated the FcRgamma promoter. This synergistic activation was suggested to require physical interaction between the two transcription factors, because the Ets domain of GABPalpha was demonstrated to directly bind Sp1. On the other hand, GABP and Elf-1, whose recognition sequences overlapped, were shown to bind the FcRgamma gene with similar affinity in the context of chromatin, although Elf-1 exerted weaker enhancer activity for FcRgamma gene expression than did GABP. Both were thought to compete for binding to the element, because additional expression of Elf-1 in combination with Sp1 and GABP reduced FcRgamma promoter activity. Such functional and physical interactions among transcription factors involved in the cooperative regulation of FcRgamma gene expression as revealed in this study will become promising targets for medical applications against various immune diseases involving FcRgamma.

Molecular mechanisms for transcriptional regulation of human high-affinity IgE receptor beta-chain gene induced by GM-CSF.

The beta-chain of the high-affinity receptor for IgE (FcepsilonRI) plays an important role in regulating activation of FcepsilonRI-expressing cells such as mast cells in allergic reactions. We already reported that the transcription factor myeloid zinc finger (MZF) 1 which formed a high m.w. complex including four and a half LIM-only protein (FHL)3 in the nucleus repressed human beta-chain gene expression through an element in the fourth intron. We also found that GM-CSF induced expression of MZF-1 and nuclear translocation of FHL3. We screened a human cDNA library and identified NFY which was reported to bind histone deacetylases (HDACs) as a constituent of the complex. The C-subunit of NFY was demonstrated to form a ternary complex with MZF-1/FHL3 and interact with a beta-chain gene region including the element in the fourth intron. HDAC1 and HDAC2 were also shown to interact with the fourth intron region of the beta-chain gene. In a human mast cell line HMC-1 cultured with GM-CSF, both beta-chain expression and acetylation of histones interacting with the fourth intron region of the beta-chain gene were decreased. Collectively, these results indicated that HDACs, which were recruited to the beta-chain gene through the element in the fourth intron by MZF-1/FHL3/NFY, repressed beta-chain gene transcription by deacetylation of histones in the presence of GM-CSF. These mechanisms will be involved in not only the cell type-specific repression of beta-chain gene expression in differentiating hemopoietic cells but also the repression of beta-chain gene expression in the peripheral cells under specific circumstances.