Malt1-induced cleavage of regnase-1 in CD4(+) helper T cells regulates immune activation.

Regnase-1 (also known as Zc3h12a and MCPIP1) is an RNase that destabilizes a set of mRNAs, including Il6 and Il12b, through cleavage of their 3' UTRs. Although Regnase-1 inactivation leads to development of an autoimmune disease characterized by T cell activation and hyperimmunoglobulinemia in mice, the mechanism of Regnase-1-mediated immune regulation has remained unclear. We show that Regnase-1 is essential for preventing aberrant effector CD4(+) T cell generation cell autonomously. Moreover, in T cells, Regnase-1 regulates the mRNAs of a set of genes, including c-Rel, Ox40, and Il2, through cleavage of their 3' UTRs. Interestingly, T cell receptor (TCR) stimulation leads to cleavage of Regnase-1 at R111 by Malt1/paracaspase, freeing T cells from Regnase-1-mediated suppression. Furthermore, Malt1 protease activity is critical for controlling the mRNA stability of T cell effector genes. Collectively, these results indicate that dynamic control of Regnase-1 expression in T cells is critical for controlling T cell activation.

The IκB kinase complex regulates the stability of cytokine-encoding mRNA induced by TLR-IL-1R by controlling degradation of regnase-1.

Toll-like receptor (TLR) signaling activates the inhibitor of transcription factor NF-κB (IκB) kinase (IKK) complex, which governs NF-κB-mediated transcription during inflammation. The RNase regnase-1 serves a critical role in preventing autoimmunity by controlling the stability of mRNAs that encode cytokines. Here we show that the IKK complex controlled the stability of mRNA for interleukin 6 (IL-6) by phosphorylating regnase-1 in response to stimulation via the IL-1 receptor (IL-1R) or TLR. Phosphorylated regnase-1 underwent ubiquitination and degradation. Regnase-1 was reexpressed in IL-1R- or TLR-activated cells after a period of lower expression. Regnase-1 mRNA was negatively regulated by regnase-1 itself via a stem-loop region present in the regnase-1 3' untranslated region. Our data demonstrate that the IKK complex phosphorylates not only IκBα, thereby activating transcription, but also regnase-1, thereby releasing a 'brake' on IL-6 mRNA expression.

[Pacemaker Dislocation into the Peritoneal Cavity].

A 16-day-old neonate with congenital complete atrioventricular block underwent epicardial pacemaker implantation under the rectus. Four months later, abodominal X-ray imaging revealed dislocation of the generator from the abdomen to the pelvis. The infant was diagnosed with intraperitoneal pacemaker dislocation. However, there were no abdominal manifestations or complications associated with the bowel, urinary tract, and vascular system. Surgical refixation was performed in a hybrid room. Fluoroscopy helped avoid bowel injury when removing the generator from the peritoneal cavity. The pacing lead, which was adherent and entangled with the omentum, was released under direct vision. The generator was placed in a new pocket created in the subcutaneous layer of the anterior fascia of the rectus.

Pivotal role of RNA-binding E3 ubiquitin ligase MEX3C in RIG-I-mediated antiviral innate immunity.

The RIG-I-like receptors, retinoic acid inducible gene-1 (RIG-I), melanoma differentiation-associated protein 5, and laboratory of genetics and physiology-2, are cytoplasmic sensors for RNA viruses that mediate the antiviral innate immune responses. We demonstrate that really interesting new gene-finger domain- and K homology domain-containing MEX3C regulates RIG-I function. MEX3C colocalizes with RIG-I in the stress granules of virally infected cells, and its overexpression causes the lysine-63-linked ubiquitination of RIG-I and activates IFN-ß promoter. Embryonic fibroblast cells, macrophages, and conventional dendritic cells derived from Mex3c-deficient mice showed defective production of type I IFN after infection with RNA viruses that are recognized by RIG-I. These results demonstrate that MEX3C is an E3 ubiquitin ligase that modifies RIG-I in stress granules and plays a critical role in eliciting antiviral immune responses.

Virus myocarditis in a 1-month-old boy presenting as two types of paroxysmal supraventricular tachycardia.

Herein we describe the case of a 1-month-old boy with acute viral myocarditis, who presented with two kinds of paroxysmal supraventricular tachycardia, and who was cured after medical treatment. He was brought to the emergency room with poor feeding due to fever. On the third day of hospitalization, a narrow QRS tachycardia (180-200 beats/min) was detected. Echocardiography showed a high echoic area at the atrial septum around the atrioventricular node. The patient was clinically diagnosed with acute myocarditis. The narrow QRS tachycardia was diagnosed as incessant junctional ectopic tachycardia. The patient was treated with propranolol and landiolol. The frequency of the tachycardia decreased, but a different narrow QRS tachycardia was detected on the 15th day of hospitalization on electrocardiogram (220 beats/min), which was ascribed to atrioventricular nodal re-entrant tachycardia. Atenolol was effective for the tachycardia. At 2 years follow up, cardiac function was normal and tachycardia had not recurred.

Tolvaptan therapy for massive edema in a patient with nephrotic syndrome.

BACKGROUND: Nephrotic syndrome (NS) is characterized by water and sodium retention, which leads to edema. The non-osmotic stimulation of arginine vasopressin release from the pituitary gland has been implicated as one of the important factors in abnormal water retention in patients with NS. CASE-DIAGNOSIS/TREATMENT: We present the initial description of a patient with massive edema caused by refractory nephrotic syndrome, which was effectively treated with tolvaptan, a selective oral vasopressin V2 receptor antagonist. CONCLUSIONS: Tolvaptan is effective for the treatment of massive edema caused by NS. Larger studies are needed in the future to fully assess the value and safety of tolvaptan use for this condition.

[Timely colonoscopy leads to faster identification of bleeding diverticulum].

We conducted a retrospective study of the efficacy of a polyethylene glycol purge before colonoscopic examination in 110 patients with colonic diverticular bleeding. The patients' data were assessed for the timing of colonoscopy and the methods used to stop bleeding. The rate at which bleeding diverticula were identified was markedly higher when a purge was used than when it was not (28.2% vs. 12.0%, p=0.11). In addition, the identification rate was significantly higher when colonoscopic examination was performed within 18 hours of the final hematochezia than when it was performed after 18 hours (40.5% vs. 10.5%, p<0.01). These findings suggest that patients with diverticular bleeding should undergo colonoscopy following an orally administered colonic purge, providing their condition permits. Furthermore, colonoscopy should be performed within 18 hours of the final hematochezia in order to improve identification of the bleeding diverticulum.

Induction of late airway response was involved in serum antigen-specific immunoglobulin G in rats.

The antigen-induced immediate airway response (IAR) has been considered a form of bronchoconstriction mainly provoked by histamine and leukotriene C4/D4/E4, which are released by stimulation by antigen-specific IgE. However, the pathophysiological features of the antigen-induced late airway response (LAR) are not yet fully understood. In the present study, sensitized rats were repeatedly exposed to ovalbumin (OVA) to induce IAR and LAR, and the immunological profiles of IAR and LAR were examined. The first antigen inhalation induced only IAR but not LAR. However, the second antigen inhalation 7 days after IAR induced LAR but not IAR. Tumor necrosis factor (TNF)-alpha level in BALF in LAR was significantly higher than that in IAR, although there were no differences in histamine, leukotriene C4/D4/E4, interleukin (IL)-1beta, or IL-13 levels between IAR and LAR. Serum antigen-specific IgE titer was high in both IAR and LAR, but serum antigen-specific IgG, IgG1, and IgG2a titers were dramatically high in LAR but not IAR. There were significant correlations between antigen-specific IgG, IgG1, and IgG2a titers and LAR. Interestingly, LAR could be induced in normal rats by transfer of serum from LAR rats, which exhibited high antigen-specific IgG, IgG1, and IgG2a titers. In conclusion, these findings suggest that repeated antigen inhalation converts IAR to LAR, and that LAR is a reaction triggered by antigen-specific IgG and involving TNF-alpha. This is the first study to directly suggest the involvement of antigen-specific IgG in the induction of LAR.

JTE-852, a novel spleen tyrosine kinase inhibitor, blocks antigen-induced allergic reactions in rats.

Conventional clinical treatments for allergy management remain suboptimal; new, orally available medications that improve a wide range of allergic signs have been desired. We previously demonstrated that JTE-852, a novel spleen tyrosine kinase inhibitor, potently and simultaneously suppresses secretion of granule contents, arachidonate metabolites, and cytokines from mast cells stimulated by immunoglobulin E-crosslinking. In the present study, we investigated the effects of JTE-852 in four rat models (sneezing, rhinorrhea, airway constriction, and airway inflammation) as representatives of allergy models. Rats were sensitized and challenged with antigen. Allergic reactions developed after challenge were detected. JTE-852 and current anti-allergic drugs (ketotifen, pranlukast, and prednisolone) were administered orally before challenge. JTE-852 showed significant blocking effects on antigen-induced allergic reactions in all models, indicating that JTE-852 in oral dosage form would improve a wide range of allergic signs. The current anti-allergic drugs, on the other hand, failed to display significant suppression in several models. Because JTE-852 suppresses the secretion of all three groups of allergic mediators from mast cells, it would be capable of targeting signs that current drugs cannot sufficiently relieve. We anticipate JTE-852 to be a promising new anti-allergic drug that is potentially more effective than conventional drugs.

Safety and efficacy of ultra-tapered mechanical dilator for EUS-guided hepaticogastrostomy and pancreatic duct drainage compared with electrocautery dilator (with video).

BACKGROUND AND OBJECTIVES: Successful tract dilation is one of the most important steps to accomplish EUS-guided drainage. Although mechanical dilation is safer than electrocautery dilation, no dedicated mechanical dilator (MD) is currently available. Thus, we developed a new ultra-tapered MD for EUS-guided drainage. This study aimed to evaluate the safety and usefulness of this novel MD. PATIENTS AND METHODS: Consecutive patients who underwent EUS-guided hepaticogastrostomy (EUS-HGS) or EUS-guided pancreatic duct drainage (EUS-PD) at two centers were included in the study. Dilation of the needle tract was initially performed with a diathermic sheath or the ultra-tapered MD. Technical success and adverse events were assessed. RESULTS: Sixty-four patients (mean age = 68.9 ± 13.8 years, 35 men) underwent EUS-HGS (49 patients) and EUS-PD (15 patients). Thirty-three patients were included in the cautery dilator (CD) group and 31 in the ultra-tapered MD group. Initial dilation of the puncture site was achieved in 95.3% (61/64): 97% (32/33) of the patients in the CD group and 93.3% (29/31) of the patients in the MD group (P < 0.05). Adverse events were observed in 14 patients: abdominal pain in 8 patients and bleeding in 6 patients at the puncture site. All bleedings occurred in the CD group and there was no patient in whom bleeding occurred after EUS intervention in the MD group (P = 0.04). CONCLUSION: The novel ultra-tapered MD designed for interventional EUS appears to be safe and useful as it reduced postprocedure bleeding with a high technical success rate compared with the conventional electrocautery dilator.

JTE-852, a novel spleen tyrosine kinase inhibitor, blocks mediator secretion from mast cells with immunoglobulin E crosslinking.

Mast cells stimulated by immunoglobulin E (IgE)-crosslinking secrete mediators, which are mainly categorized into three groups: granule contents, arachidonate metabolites, and cytokines. These mediators play important roles in pathogenesis of allergic diseases; indeed, some conventional drugs which target the mediators are used in clinical practices. However, these drugs are not yet sufficient enough in their efficacy. That is because most of them are blockers of single mediators and are unable to prevent simultaneously various reactions caused by the three group mediators. Spleen tyrosine kinase (Syk) is a non-receptor protein tyrosine kinase. In mast cells, Syk locates at almost top of the signal cascades induced by IgE-crosslinking and plays pivotal roles in secretion of the three groups of mediators. Therefore, inhibition of Syk would suppress the secretion of all the mediators from mast cells and be a promising-treatment strategy for allergic diseases. In the present study, we characterized pharmacological profiles of JTE-852, which was identified as a novel Syk inhibitor. JTE-852 inhibited kinase activity of Syk in an adenosine 5'-triphosphate (ATP)-competitive fashion. JTE-852 also blocked the secretion of granule contents, arachidonate metabolites, and cytokines from mast cells stimulated by IgE-crosslinking, with similar potencies. The results suggest that JTE-852 is supposed to prevent various allergic reactions caused by the three group mediators in vivo. In fact, oral gavage of JTE-852 attenuated an allergic reaction mediated by histamine, which is a representative of the three groups of mediators. JTE-852 is expected to be a novel, highly-efficacious, and orally available anti-allergic drug.

JTE-852, a novel spleen tyrosine kinase inhibitor, blocks immunoglobulin G-mediated cellular responses and autoimmune reactions in vivo.

AIMS: Immune and inflammatory responses mediated by immunoglobulin (Ig) G are largely responsible for the pathogenesis of autoimmune diseases. Spleen tyrosine kinase (Syk) plays a pivotal role in the IgG-mediated responses; therefore, Syk has emerged as a new therapeutic target for the treatment of autoimmune diseases. In this study, we investigated the inhibitory actions of JTE-852, a novel Syk inhibitor, on IgG-mediated cellular responses and autoimmune reactions in vivo. MAIN METHODS: We examined mediator secretion from human monocytes. We also conducted rat models of reversed cutaneous anaphylaxis (RCA) and reversed passive Arthus (RPA), which are classified as type II and type III hypersensitivities, respectively. In a rat collagen-induced arthritis (CIA) model, JTE-852 or methotrexate was administered preventively (before the onset of arthritis) or therapeutically (after the onset of arthritis). KEY FINDINGS: JTE-852 blocked secretion of reactive oxygen species and tumor necrosis factor-α from monocytes stimulated by IgG crosslinking. In the RCA and RPA models, JTE-852 also suppressed edema and dye leakage, respectively. In the CIA model, JTE-852 showed both preventive and therapeutic effects against joint swelling and bone erosion; on the other hand, methotrexate did not show the therapeutic effect. SIGNIFICANCE: JTE-852 attenuates IgG-mediated responses and signs in animal model of autoimmune diseases. JTE-852 is thus a promising candidate for a novel, orally available drug for the treatment of autoimmune diseases.

Successful treatment of primary sclerosing cholangitis with a steroid and a probiotic.

Primary sclerosing cholangitis (PSC) is a serious disease that not only affects quality of life but can also have a significant effect on patient survival. The treatment for PSC is primarily supportive with the aim of controlling cholestatic symptoms and preventing complications. Ursodeoxycholic acid may induce biochemical improvements in affected patients; however, long-term pediatric studies to determine its possible benefits in young patients are lacking. Thus, the treatment of pediatric PSC remains a significant clinical challenge. We describe a patient with PSC and undetermined colitis who was treated with a combination of a steroid, salazosulfapyridine, and a probiotic. This treatment provided benefits both for PSC and the undetermined colitis. These findings suggest that bacterial flora and gut inflammation are closely associated with the pathogenesis of inflammatory bowel disease-related PSC. Suppression of bowel inflammation and maintenance of bacterial homeostasis may be important for treating PSC.

Neutrophil extracellular traps mediate a host defense response to human immunodeficiency virus-1.

Neutrophils contribute to pathogen clearance by producing neutrophil extracellular traps (NETs), which are genomic DNA-based net-like structures that capture bacteria and fungi. Although NETs also express antiviral factors, such as myeloperoxidase and α-defensin, the involvement of NETs in antiviral responses remains unclear. We show that NETs capture human immunodeficiency virus (HIV)-1 and promote HIV-1 elimination through myeloperoxidase and α-defensin. Neutrophils detect HIV-1 by Toll-like receptors (TLRs) TLR7 and TLR8, which recognize viral nucleic acids. Engagement of TLR7 and TLR8 induces the generation of reactive oxygen species that trigger NET formation, leading to NET-dependent HIV-1 elimination. However, HIV-1 counteracts this response by inducing C-type lectin CD209-dependent production of interleukin (IL)-10 by dendritic cells to inhibit NET formation. IL-10 suppresses the reactive oxygen species-dependent generation of NETs induced upon TLR7 and TLR8 engagement, resulting in disrupted NET-dependent HIV-1 elimination. Therefore, NET formation is an antiviral response that is counteracted by HIV-1.

Pharmacological analysis of antigen-induced late airway response in rats.

The pharmacological and pathophysiological characteristics of rat antigen-induced late airway response (LAR) are not yet fully understood. In this study, the pharmacological properties of rat ovalbumin (OVA)-induced LAR and effects of the clinically used anti-asthmatic drugs salbutamol (beta2-agonist), ketotifen (antihistamine), pranlukast (anti-leukotriene C4/D4/E4), and prednisolone (steroid) were examined. In addition, a comparison was made of cell infiltration in bronchoalveolar lavage fluid (BALF) between immediate airway response (IAR) and LAR, and the edematous features of lung during LAR were also examined. Although infiltration of inflammatory cells into BALF was increased in both IAR and LAR, only the increase in eosinophils at 1, 3, and 6 h during LAR were significantly higher than those during IAR. Although beta2-agonist, antihistamine, and anti-leukotriene C4/D4/E4 exhibited no effects on rat LAR, steroid attenuated LAR and decreased eosinophil number in BALF. LAR and the percentage water content were both increased after antigen inhalation, suggesting that LAR is involved in pulmonary edema in rats. In conclusion, antigen-induced LAR was related to pulmonary edema and eosinophil infiltration rather than contraction of airway smooth muscle. This is the first comprehensive study of the profiles of rat antigen-induced LAR, and these analyses of LAR improve understanding of the diverse mechanisms underlying human asthmatic diseases.

Two pharmacological phases in antigen-induced immediate airway response in rats.

The pharmacological profiles of antigen-induced immediate airway response (IAR) in rats are not fully understood. In this study, we established an ovalbumin (OVA)-induced IAR model using noninvasive measurement in rats, and evaluated the effects of commonly used and effective antiasthmatic drugs, i.e. ketotifen (antihistamine), pranlukast (anti-leukotriene C(4)/D(4)/E(4) (LT)), seratrodast (anti-thromboxane A(2) (TXA(2))), salbutamol (beta2-agonist), and prednisolone (steroid). The rat IAR model exhibited an optimal rapid airway response, and salbutamol inhalation completely suppressed the IAR. Ketotifen inhibited only the quick phase (QP; the reaction from 3 to 6 min after challenge), while pranlukast and seratrodast suppressed only the early phase (EP; the reaction from 6 to 30 min after challenge). Prednisolone inhibited both QP and EP. Further, continuous administration of compound 48/80, which depletes connective tissue mast cells (CTMC), partially inhibited QP but not EP. In conclusion, these findings suggest that the pharmacological profiles of noninvasive rat IAR are similar to those of asthmatic patients, and that rat IAR exhibits additional, immunological diverse characteristics, i.e. QP caused by the exocytosis of mediators in CTMCs and EP mediated by LT and TXA(2), which are produced by mucosal mast cells (MMCs) and possibly by other types of cells. This is the first report about the comprehensive pharmacological profiles of rodent IAR model, and these analyses of rat IAR model may help expand our understanding of the diverse mechanisms underlying human asthmatic diseases.