Effect of Lurasidone on Social Functioning in Schizophrenia: Post Hoc Analysis of the JEWEL Study.

Objective: To evaluate the effects of lurasidone on social functioning in schizophrenia over the course of a 6-week, double-blind, placebo-controlled study and a subsequent 12-week open-label extension study.Methods: A total of 478 patients with schizophrenia (per DSM-IV-TR criteria) randomized to either lurasidone 40 mg/d (n = 245) or placebo (n = 233) in the initial 6-week double-blind study (initiated May 2016, completed November 2018) were included in the analysis. Longer-term changes were examined in a sample of 146 patients who received lurasidone, and 141 who received placebo, during the 6-week study and received flexibly dosed (40-80 mg/d) lurasidone during the 12-week extension phase. The 4-item Positive and Negative Syndrome Scale (PANSS) prosocial subscale was used to examine changes in social functioning.Results: At week 6 of the double-blind phase, lurasidone-treated patients had significantly greater improvement on the PANSS prosocial subscale compared to placebo-treated patients (P < .01, effect size at week 6 = 0.33). Significant differences from placebo were also evident at week 2 (P < .05), week 4 (P < .001), and week 5 (P < .01). Across the 12-week extension phase, patients who received lurasidone during both the 6-week double-blind phase and the 12-week open-label phase continued to show successive decreases in scores on the 4-item PANSS prosocial subscale (score change of -3.0 from double-blind baseline to week 6; mean score change of -4.2 from double-blind baseline to week 12 of the extension phase).Conclusions: In patients with schizophrenia treated with lurasidone, social functioning improved relative to placebo during a 6-week double-blind study and continued to improve over the course of 12 weeks of extension treatment with lurasidone. Effects of lurasidone on social functioning appear to be comparable to what has been reported for other atypical antipsychotics.Trial Registration: EudraCT Numbers: 2016-000060-42 and 2016-000061-23.

Effectiveness of Lurasidone 80 mg in Patients with Schizophrenia: Results of an Open-Label, 12-Week Extension Study.

Purpose: To evaluate the effectiveness and safety of lurasidone 80 mg/day (versus the 40 mg/day dose) during a 12-week, open-label extension study in patients with an acute exacerbation of schizophrenia who had completed a 6-week double-blind study of lurasidone. Patients and Methods: A total of 289 adult patients with schizophrenia completed the double-blind study and enrolled in the 12-week extension study. Lurasidone was flexibly dosed at 40 or 80 mg/day. Effectiveness measures included the Positive and Negative Syndrome Scale (PANSS) subscale scores, Clinical Global Impression-Severity Scale (CGI-S), and Calgary Depression Scale for Schizophrenia (CDSS), analyzed based on last observation carried forward (LOCF-endpoint). Safety/tolerability assessments included adverse events, body weight, laboratory tests, and discontinuation due to adverse events. Results: Mean endpoint change was greater for lurasidone in modal doses of 80 mg/d (N=136) vs 40 mg/d (N=153) on the PANSS positive subscale (-3.0 vs -2.3), PANSS negative subscale (-1.9 vs -1.7), PANSS General Psychopathology subscale (-5.1 vs -3.8), the CGI-S score (-0.5 vs -0.4), and the CDSS score (-0.7 vs -0.1). Discontinuation rates due to adverse events on lurasidone modal 80 mg/d vs 40 mg/d were 4.4% vs 7.2%; and the most common adverse events in the modal 80 mg/d group were nasopharyngitis, 7.4% (vs 4.6% on modal 40 mg/d), constipation, 5.9% (vs 2.0%), and headache, 5.9% (vs 2.0%). Conclusion: In patients with acute schizophrenia treated with lurasidone 40 mg/d, increasing the dose to 80 mg/d was well tolerated, and was associated with greater improvement in PANSS subscale scores compared to continued treatment with a dose of 40 mg/d.

Photoactive carbon monoxide-releasing coordination polymer particles.

We report the synthesis of photoactive carbon monoxide-releasing coordination polymer particles through the assembly of Mn(I) carbonyl complexes with bis(imidazole) ligands. The use of Mn(I) carbonyl complexes as metallic nodes in the coordination network avoids the potential for aggregation-induced self-quenching, favouring their use in the solid state.

A two-step screening to optimize the signal response of an auto-fluorescent protein-based biosensor.

Auto-fluorescent protein (AFP)-based biosensors transduce the structural change in their embedded recognition modules induced by recognition/reaction events to fluorescence signal changes of AFP. The lack of detailed structural information on the recognition module often makes it difficult to optimize AFP-based biosensors. To enhance the signal response derived from detecting the putative structural change in the nitric oxide (NO)-sensing segment of transient receptor potential canonical 5 (TRPC5) fused to enhanced green fluorescent protein (EGFP), EGFP-TRPC5, a facile two-step screening strategy, in silico first and in vitro second, was applied to variants of EGFP-TRPC5 deletion-mutated within the recognition module. In in silico screening, the structural changes of the recognition modules were evaluated as root-mean-square-deviation (RMSD) values, and 10 candidates were efficiently selected from 47 derivatives. Through in vitro screening, four mutants were identified that showed a larger change in signal response than the parent EGFP-TRPC5. One mutant in particular, 551-575, showed four times larger change upon reaction with NO and H2O2. Furthermore, mutant 551-575 also showed a signal response upon reaction with H2O2 in mammalian HEK293 cells, indicating that the mutant has the potential to be applied as a biosensor for cell measurement. Therefore, this two-step screening method effectively allows the selection of AFP-based biosensors with sufficiently enhanced signal responses for application in mammalian cells.

Critical contributions of pre-S1 shoulder and distal TRP box in DAG-activated TRPC6 channel by PIP2 regulation.

Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2 or PIP2) regulates the activities of numerous membrane proteins, including diacylglycerol(DAG)-activated TRPC3/6/7 channels. Although PIP2 binding is known to support DAG-activated TRP channel activity, its binding site remains unknown. We screened for PIP2 binding sites within TRPC6 channels through extensive mutagenesis. Using voltage-sensitive phosphatase (DrVSP), we found that Arg437 and Lys442, located in the channel's pre-S1 domain/shoulder, are crucial for interaction with PIP2. To gain structural insights, we conducted computer protein-ligand docking simulations with the pre-S1 domain/shoulder of TRPC6 channels. Further, the functional significance of PIP2 binding to the pre-S1 shoulder was assessed for receptor-operated channel functions, cross-reactivity to DAG activation, and the kinetic model simulation. These results revealed that basic residues in the pre-S1 domain/shoulder play a central role in the regulation of PIP2-dependent gating. In addition, neutralizing mutation of K771 in the distal TRP box reversed the effect of PIP2 depletion from inhibiting to potentiating channel activity. A similar effect was seen in TRPV1 channels, which suggests that TRPC6 possesses a common but robust polarity switch mediating the PIP2-dependent effect. Overall, these mutagenesis studies reveal functional and structural insights for how basic residues and channel segments in TRP channels are controlled through phosphoinositides recognition.

Cell-autonomous control of intracellular temperature by unsaturation of phospholipid acyl chains.

Intracellular temperature affects a wide range of cellular functions in living organisms. However, it remains unclear whether temperature in individual animal cells is controlled autonomously as a response to fluctuations in environmental temperature. Using two distinct intracellular thermometers, we find that the intracellular temperature of steady-state Drosophila S2 cells is maintained in a manner dependent on Δ9-fatty acid desaturase DESAT1, which introduces a double bond at the Δ9 position of the acyl moiety of acyl-CoA. The DESAT1-mediated increase of intracellular temperature is caused by the enhancement of F1Fo-ATPase-dependent mitochondrial respiration, which is coupled with thermogenesis. We also reveal that F1Fo-ATPase-dependent mitochondrial respiration is potentiated by cold exposure through the remodeling of mitochondrial cristae structures via DESAT1-dependent unsaturation of mitochondrial phospholipid acyl chains. Based on these findings, we propose a cell-autonomous mechanism for intracellular temperature control during environmental temperature changes.

Determination of the physiological range of oxygen tension in bone marrow monocytes using two-photon phosphorescence lifetime imaging microscopy.

Oxygen is a key regulator of both development and homeostasis. To study the role of oxygen, a variety of in vitro and ex vivo cell and tissue models have been used in biomedical research. However, because of ambiguity surrounding the level of oxygen that cells experience in vivo, the cellular pathway related to oxygenation state and hypoxia have been inadequately studied in many of these models. Here, we devised a method to determine the oxygen tension in bone marrow monocytes using two-photon phosphorescence lifetime imaging microscopy with the cell-penetrating phosphorescent probe, BTPDM1. Phosphorescence lifetime imaging revealed the physiological level of oxygen tension in monocytes to be 5.3% in live mice exposed to normal air. When the mice inhaled hypoxic air, the level of oxygen tension in bone marrow monocytes decreased to 2.4%. By performing in vitro cell culture experiment within the physiological range of oxygen tension, hypoxia changed the molecular phenotype of monocytes, leading to enhanced the expression of CD169 and CD206, which are markers of a unique subset of macrophages in bone marrow, osteal macrophages. This current study enables the determination of the physiological range of oxygen tension in bone marrow with spatial resolution at a cellular level and application of this information on oxygen tension in vivo to in vitro assays. Quantifying oxygen tension in tissues can provide invaluable information on metabolism under physiological and pathophyisological conditions. This method will open new avenues for research on oxygen biology.

Efficacy and Safety of Blonanserin Oral Tablet in Adolescents with Schizophrenia: A 6-Week, Randomized Placebo-Controlled Study.

Objectives: To evaluate the short-term efficacy and safety of blonanserin in adolescents with schizophrenia. Methods: This 6-week multicenter, double-blind, randomized, placebo-controlled study investigated fixed-dose blonanserin (8 or 16 mg/day) in patients 12-18 years of age diagnosed with schizophrenia, as indicated by a Positive and Negative Syndrome Scale (PANSS) total score of 60-120 and a Clinical Global Impressions-Severity score of ≥3. The primary endpoint was change from baseline to week 6 in the PANSS total score, using a mixed model for repeated measures analysis. Safety was assessed by the incidence and severity of adverse events (AEs). Results: Among 151 randomized patients, 150 were included in the primary analysis population. Demographic and clinical characteristics were similar across groups at baseline. The rate of study discontinuation was 14.9%, 23.5%, and 28.3% in patients administered with placebo, blonanserin 8 mg/day, and blonanserin 16 mg/day, respectively. The least-squares mean change (95% confidence interval [CI]) from baseline to week 6 in PANSS total score was -10.6 (-16.10 to -5.10), -15.3 (-20.80 to -9.86), and -20.5 (-25.89 to -15.16) in patients administered placebo, 8 mg/day blonanserin, and 16 mg/day blonanserin, respectively. The 16-mg/day blonanserin group showed significantly greater reduction in the PANSS total score than the placebo group (least-squares mean difference [95% CI]: -9.9 [-17.61 to -2.25], p = 0.012, effect size: 0.538), although the 8-mg/day group showed no significant difference. The incidence of AEs such as akathisia, somnolence, and hyperprolactinemia was higher in the blonanserin groups than in the placebo group. AEs associated with blonanserin were generally mild and were consistent with its known profile in adults with schizophrenia. Conclusions: Blonanserin achieved a sufficient efficacy in adolescent patients, and the safety profile was similar to that in adults, which suggests that blonanserin may be a safe treatment option for adolescents with schizophrenia. Study registration number: Japic CTI-111724.

Long-Term Safety and Efficacy of Blonanserin Oral Tablet in Adolescents with Schizophrenia: A 52-Week, Multicenter, Open-Label Extension Study.

Objectives: To evaluate the long-term efficacy and safety/tolerability of oral blonanserin in adolescents with schizophrenia (Study registration number: JapicCTI-111725). Methods: This 52-week, multicenter, open-label extension study enrolled adolescent patients with schizophrenia who opted to enter in this study after the completion of the preceding placebo-controlled study. Blonanserin tablet was orally administered twice daily, after morning and evening meals, for 52 weeks using dose-titration method within a range between 4 and 24 mg/day. The primary end point was the change from baseline to the end of the study in the Positive and Negative Syndrome Scale (PANSS) total score. Safety/tolerability was assessed by the incidence and severity of adverse events. Results: Of 117 patients who completed the preceding placebo-controlled study, 109 entered this extension study and 43 (39.4%) of them discontinued the study treatment. The safety analysis set comprised 106 patients who received the study drug at least once, including 36 and 70 patients treated with placebo (DB-placebo group) and blonanserin tablet (DB-blonanserin group), respectively, in the placebo-controlled study. At the last assessment, the mean change in PANSS total score overall [mean (standard deviation)] was -24.9 (20.76) from the baseline of the placebo-controlled study, which was similar in the DB-placebo and DB-blonanserin groups. The overall incidence of adverse events was 90.6%, and most of them were mild or moderate in severity, with similar incidence of extrapyramidal symptoms (38.7%) to that in adults receiving long-term blonanserin oral tablet treatment and minimal change in weight and metabolic parameters. Conclusions: This long-term extension study showed that 52 weeks of oral blonanserin treatment improved or stabilized psychiatric symptoms in patients with adolescent schizophrenia. There were no major issues with the safety or tolerability of blonanserin administration in this study. Considering relatively less adverse effects on weight increase and metabolic parameters, blonanserin is expected to be a safe/tolerable treatment option for adolescent schizophrenia that can be used seamlessly from adolescence to adulthood.

Functionally deficient TRPV6 variants contribute to hereditary and familial chronic pancreatitis.

The recent discovery of TRPV6 as a pancreatitis susceptibility gene served to identify a novel mechanism of chronic pancreatitis (CP) due to Ca2+ dysregulation. Herein, we analyzed TRPV6 in 81 probands with hereditary CP (HCP), 204 probands with familial CP (FCP), and 462 patients with idiopathic CP (ICP) by targeted next-generation sequencing. We identified 25 rare nonsynonymous TRPV6 variants, 18 of which had not been previously reported. All 18 variants were characterized by a Ca2+ imaging assay, with 8 being identified as functionally deficient. Evaluation of functionally deficient variants in the three CP cohorts revealed two novel findings: (i) functionally deficient TRPV6 variants appear to occur more frequently in HCP/FCP patients than in ICP patients (3.2% vs. 1.5%) and (ii) functionally deficient TRPV6 variants found in HCP and FCP probands appear to be more frequently coinherited with known risk variants in SPINK1, CTRC, and/or CFTR than those found in ICP patients (66.7% vs 28.6%). Additionally, genetic analysis of available HCP and FCP family members revealed complex patterns of inheritance in some families. Our findings confirm that functionally deficient TRPV6 variants represent an important contributor to CP. Importantly, functionally deficient TRPV6 variants account for a significant proportion of cases of HCP/FCP.

Osteoclasts adapt to physioxia perturbation through DNA demethylation.

Oxygen plays an important role in diverse biological processes. However, since quantitation of the partial pressure of cellular oxygen in vivo is challenging, the extent of oxygen perturbation in situ and its cellular response remains underexplored. Using two-photon phosphorescence lifetime imaging microscopy, we determine the physiological range of oxygen tension in osteoclasts of live mice. We find that oxygen tension ranges from 17.4 to 36.4 mmHg, under hypoxic and normoxic conditions, respectively. Physiological normoxia thus corresponds to 5% and hypoxia to 2% oxygen in osteoclasts. Hypoxia in this range severely limits osteoclastogenesis, independent of energy metabolism and hypoxia-inducible factor activity. We observe that hypoxia decreases ten-eleven translocation (TET) activity. Tet2/3 cooperatively induces Prdm1 expression via oxygen-dependent DNA demethylation, which in turn activates NFATc1 required for osteoclastogenesis. Taken together, our results reveal that TET enzymes, acting as functional oxygen sensors, regulate osteoclastogenesis within the physiological range of oxygen tension, thus opening new avenues for research on in vivo response to oxygen perturbation.

Safety and Effectiveness of Lurasidone in Patients with Schizophrenia: A 12-Week, Open-Label Extension Study.

PURPOSE: The goal of this study was to evaluate the safety and effectiveness of lurasidone among patients with schizophrenia in a 12-week open-label extension study. PATIENTS AND METHODS: Patients who completed a 6-week, double-blind, placebo-controlled study were enrolled in a 12-week open-label extension study with flexible dosing of lurasidone at 40 or 80 mg/day. Safety assessments included adverse events, vital signs, laboratory tests, and electrocardiogram (ECG) parameters. Effectiveness measures included the Positive and Negative Syndrome Scale (PANSS) total score, Clinical Global Impression-Severity Scale (CGI-S), Calgary Depression Scale for Schizophrenia (CDSS) and quality of life measure. RESULTS: A total of 289 patients were enrolled in the open-label extension study. Rates of treatment-emergent adverse events (TEAEs) were low; akathisia was the most common TEAE with an incidence of 6.6%. There were 54 patients (18.7%) who discontinued the extension study, with 17 (5.9%) discontinuing due to adverse events. Minimal or no effects of lurasidone on weight, body mass index, metabolic parameters, prolactin, and ECG parameters were evident. There was continued improvement to week 12 in PANSS and CGI-S scores beyond the initial gains made during the prior 6-week double-blind study. Non-responders to lurasidone 40 mg/day in the prior 6-week study showed a mean (standard deviation) improvement from open-label baseline of 10.7 (13.8) points on the PANSS total score after lurasidone dose was increased to a modal dose of 80 mg/day during the extension study. Changes from double-blind baseline in CDSS and quality of life were maintained in the extension study. CONCLUSION: Treatment with lurasidone 40 or 80 mg once daily (flexibly dosed) continued to be well tolerated with patients demonstrating further improvement in symptoms over the course of a 12-week open-label extension study in patients with schizophrenia.

Efficacy and safety of lurasidone in acutely psychotic patients with schizophrenia: A 6-week, randomized, double-blind, placebo-controlled study.

AIM: The aim of this study was to evaluate the efficacy of lurasidone in acute schizophrenia in Japan and other countries. METHODS: Subjects (aged 18-74 years) diagnosed with schizophrenia were randomized to lurasidone 40 mg/day or placebo. The primary efficacy endpoint was change from baseline on the Positive and Negative Syndrome Scale (PANSS) total score at Week 6. Secondary efficacy assessments included the Clinical Global Impression-Severity Scale (CGI-S). Safety endpoints included adverse events, and laboratory and electrocardiogram parameters. RESULTS: A total of 483 subjects were randomized to lurasidone or placebo; 107 subjects were from Japan. Mean changes from baseline at Week 6 endpoint in PANSS total scores were -19.3 in the lurasidone group and -12.7 in the placebo group (treatment difference: P < 0.001, effect size = 0.41). Changes from baseline for Week 6 CGI-S scores were -1.0 for lurasidone and -0.7 for placebo (treatment difference: P < 0.001, effect size = 0.41). All-cause discontinuation during the 6-week, double-blind period was 19.4% for lurasidone and 25.4% for placebo, and discontinuation rates due to adverse event were 5.7% for lurasidone and 6.4% for placebo. The following common treatment-emergent adverse events occurred in more than 2% on lurasidone and at a rate at least twice that of the placebo group: akathisia (4.0%), dizziness (2.8%), somnolence (2.8%), abdominal discomfort (2.0%) and asthenia (2.0%). No significant changes in bodyweight or metabolic parameters were observed. CONCLUSION: Lurasidone 40 mg once daily dosing demonstrated efficacy in a patient population with acute schizophrenia, including subjects from Japan, and was generally safe and well-tolerated.

Inositol 1,4,5-trisphosphate 3-kinase B promotes Ca2+ mobilization and the inflammatory activity of dendritic cells.

Innate immune responses to Gram-negative bacteria depend on the recognition of lipopolysaccharide (LPS) by a receptor complex that includes CD14 and TLR4. In dendritic cells (DCs), CD14 enhances the activation not only of TLR4 but also that of the NFAT family of transcription factors, which suppresses cell survival and promotes the production of inflammatory mediators. NFAT activation requires Ca2+ mobilization. In DCs, Ca2+ mobilization in response to LPS depends on phospholipase C γ2 (PLCγ2), which produces inositol 1,4,5-trisphosphate (IP3). Here, we showed that the IP3 receptor 3 (IP3R3) and ITPKB, a kinase that converts IP3 to inositol 1,3,4,5-tetrakisphosphate (IP4), were both necessary for Ca2+ mobilization and NFAT activation in mouse and human DCs. A pool of IP3R3 was located on the plasma membrane of DCs, where it colocalized with CD14 and ITPKB. Upon LPS binding to CD14, ITPKB was required for Ca2+ mobilization through plasma membrane-localized IP3R3 and for NFAT nuclear translocation. Pharmacological inhibition of ITPKB in mice reduced both LPS-induced tissue swelling and the severity of inflammatory arthritis to a similar extent as that induced by the inhibition of NFAT using nanoparticles that delivered an NFAT-inhibiting peptide specifically to phagocytic cells. Our results suggest that ITPKB may represent a promising target for anti-inflammatory therapies that aim to inhibit specific DC functions.

Terahertz pulse-altered gene networks in human induced pluripotent stem cells.

Terahertz (THz) irradiation has been exploited in biomedical applications involving non-invasive manipulation of living cells. We developed an apparatus for studying the effects of THz pulse irradiation on living human induced pluripotent stem cells. The THz pulse of the maximum electric field reached 0.5 MV/cm and was applied for one hour with 1 kHz repetition to the entire cell-culture area, a diameter of 1 mm. RNA sequencing of global gene-expression revealed that many THz-regulated genes were driven by zinc-finger transcription factors. Combined with a consideration of the interactions of metal ions and a THz electric field, these results imply that the local intracellular concentration of metal ions, such as Zn2+, was changed by the effective electrical force of our THz pulse.

O2-Dependent Protein Internalization Underlies Astrocytic Sensing of Acute Hypoxia by Restricting Multimodal TRPA1 Channel Responses.

Hypoxia sensors are essential for regulating local oxygen (O2) homeostasis within the body. This is especially pertinent within the CNS, which is particularly vulnerable to O2 deprivation due to high energetic demand. Here, we reveal hypoxia-monitoring function exerted by astrocytes through an O2-regulated protein trafficking mechanism within the CNS. Strikingly, cultured mouse astrocytes isolated from the parafacial respiratory group (pFRG) and retrotrapezoid nucleus (RTN) region are capable of rapidly responding to moderate hypoxia via the sensor cation channel transient receptor potential (TRP) A1 but, unlike multimodal sensory neurons, are inert to hyperoxia and other TRPA1 activators (carbon dioxide, electrophiles, and oxidants) in normoxia. Mechanistically, O2 suppresses TRPA1 channel activity by protein internalization via O2-dependent proline hydroxylation and subsequent ubiquitination by an E3 ubiquitin ligase, NEDD4-1 (neural precursor cell-expressed developmentally down-regulated protein 4). Hypoxia inhibits this process and instantly accumulates TRPA1 proteins at the plasma membrane, inducing TRPA1-mediated Ca2+ influx that triggers ATP release from pFRG/RTN astrocytes, potentiating respiratory center activity. Furthermore, astrocyte-specific Trpa1 disruption in a mouse brainstem-spinal cord preparation impedes the amplitude augmentation of the central autonomic respiratory output during hypoxia. Thus, reversible coupling of the TRPA1 channels with O2-dependent protein translocation allows astrocytes to act as acute hypoxia sensors in the medullary respiratory center.

Fluorescence detection of the nitric oxide-induced structural change at the putative nitric oxide sensing segment of TRPC5.

The plausible nitric oxide (NO)-sensing module of TRPC5 was incorporated in a enhanced green fluorescent protein (EGFP) to evaluate its conformational change as an optical response upon the reaction with NO. Two cysteine residues located in the NO-sensing module have been proposed to form a disulfide bond through S-nitrosylation of the thiol group by NO. Modification of the cysteine residues by NO resulted a ratiometric change of EGFP emission through transducing the conformational change of NO-sensing module to the EGFP chromophore. The oxidized form of NO-sensing module fused EGFP changed the intensity of emission spectra upon reduction of the disulfide bond at the NO-reactive module. The NO-sensing module fused EGFP in its reduced form avidly reacted with NO and realized the ratiometric fluorescence intensity changes depending on the formation of disulfide bond. These results support the notion that NO induces a conformational change at the putative NO-sensing segment of TRPC5, and provide a prototype for the genetically encoded cellular NO sensors.

Variants That Affect Function of Calcium Channel TRPV6 Are Associated With Early-Onset Chronic Pancreatitis.

BACKGROUND & AIMS: Changes in pancreatic calcium levels affect secretion and might be involved in development of chronic pancreatitis (CP). We investigated the association of CP with the transient receptor potential cation channel subfamily V member 6 gene (TRPV6), which encodes a Ca2+-selective ion channel, in an international cohort of patients and in mice. METHODS: We performed whole-exome DNA sequencing from a patient with idiopathic CP and from his parents, who did not have CP. We validated our findings by sequencing DNA from 300 patients with CP (not associated with alcohol consumption) and 1070 persons from the general population in Japan (control individuals). In replication studies, we sequenced DNA from patients with early-onset CP (20 years or younger) not associated with alcohol consumption from France (n = 470) and Germany (n = 410). We expressed TRPV6 variants in HEK293 cells and measured their activity using Ca2+ imaging assays. CP was induced by repeated injections of cerulein in TRPV6mut/mut mice. RESULTS: We identified the variants c.629C>T (p.A210V) and c.970G>A (p.D324N) in TRPV6 in the index patient. Variants that affected function of the TRPV6 product were found in 13 of 300 patients (4.3%) and 1 of 1070 control individuals (0.1%) from Japan (odds ratio [OR], 48.4; 95% confidence interval [CI], 6.3-371.7; P = 2.4 × 10-8). Twelve of 124 patients (9.7%) with early-onset CP had such variants. In the replication set from Europe, 18 patients with CP (2.0%) carried variants that affected the function of the TRPV6 product compared with 0 control individuals (P = 6.2 × 10-8). Variants that did not affect the function of the TRPV6 product (p.I223T and p.D324N) were overrepresented in Japanese patients vs control individuals (OR, 10.9; 95% CI, 4.5-25.9; P = 7.4 × 10-9 for p.I223T and P = .01 for p.D324N), whereas the p.L299Q was overrepresented in European patients vs control individuals (OR, 3.0; 95% CI, 1.9-4.8; P = 1.2 × 10-5). TRPV6mut/mut mice given cerulein developed more severe pancreatitis than control mice, as shown by increased levels of pancreatic enzymes, histologic alterations, and pancreatic fibrosis. CONCLUSIONS: We found that patients with early-onset CP not associated with alcohol consumption carry variants in TRPV6 that affect the function of its product, perhaps by altering Ca2+ balance in pancreatic cells. TRPV6 regulates Ca2+ homeostasis and pancreatic inflammation.

Transient receptor potential (TRP) channels: Biosensors for redox environmental stimuli and cellular status.

Transient receptor potential (TRP) channels are a family of cation channels that depolarizes the membrane potential and regulates intracellular concentrations of cations such as Ca2+. TRP channels are also known to function as "biosensors" to detect changes of the surrounding environment and cellular status. Lines of evidence have unveiled that numerous proteins are subject to redox modification and subsequent signaling. For example, TRPM2, TRPC5, TRPV1, and TRPA1 are known as redox sensors activated by hydrogen peroxide (H2O2), nitric oxide (NO), and electrophiles. Thus, these channels facilitate the influx of cations which in turn triggers the appropriate cellular responses against environmental redox stimuli and cellular redox status. In this review, we focus on the recent findings regarding the functions of TRP channels in relation to other ion channels, and other proteins which also go through redox modification of cysteine (Cys) residues. We aim to understand the structural and molecular basis of the redox-sensing mechanisms of TRP channels in exerting various functions under physiological conditions as well as pathological conditions such as cancer malignancy. Their future potential as drug targets will also be discussed.

Detection of Inositol Phosphates by Split PH Domains.

The pleckstrin homology (PH) domain is a family of structurally conserved proteins which can bind inositol phosphate derivatives. Some proteins involved in cellular signaling and cytoskeletal organization possess split PH domains that assemble into a structure which can bind specific inositol phosphates. Here we describe the design of split PH domain from a structurally well-characterized PH domain of phospholipase C (PLC) δ1 and Bruton's tyrosine kinase (Btk), which selectively bind Ins(1,4,5)P3 and Ins(1,3,4,5)P4, respectively. The PH domains fold into a functional structure when the split halves are brought to close proximity, and can be utilized to detect specific inositol phosphate of interest.