RESUMEN
Our study, conducted between April 2022 and January 2024, was aimed at clarifying components of the rest-activity rhythm (RAR) involved in improvement of social frailty state before or after a 3-month multi-component exercise intervention in the elderly. Participants were recruited from the general population in Akita prefecture, Japan. We administered a four-item social frailty screening questionnaire to classify the severity of social frailty in each participant before and after the 3-month intervention. The RAR parameters were measured on an Actiwatch Spectrum Plus device worn by the subjects for 7 continuous days. As the final sample, 65 participants classified into the improved/maintained group (n = 36) or the deteriorated group (n = 29) according to the change in the social frailty classification after the intervention were included in the analysis. The results of a binomial logistic regression analysis showed significantly higher values of interdaily stability (IS) and usual walking speed at the post-test after the intervention. Based on our findings, we propose that stability of the rest-activity rhythm related to synchronization with external stimuli (such as social effect and physical activity) might have clinical impact on improvement of social frailty state in elderly community-dwellers.
RESUMEN
BACKGROUND: Effects of a multicomponent exercise programme have an impact on the physical, cognitive, and psychological domains in elderly community-dwellers. However, some individuals aged 65 years or more have not shown positive effects after the intervention as reported in similar research. The objective of this quasi-experimental study was to clarify the effectiveness of a multicomponent programme based on reality orientation therapy (ROT) on the physical performance, cognitive ability, and psychological state in the elderly. METHOD: Participants were recruited from the general public in 20 areas of Akita Prefecture, Japan, and they took part in each exercise programme for 90 min a day, once every 2 weeks, for 3 months, according to the group classification using cluster randomization into 20 cohorts in Akita. Physical, cognitive, and geriatric depression assessments were performed at baseline and after the 3-month intervention in both the ROT-based intervention group and the control group. RESULT: The final samples for analysis consisted of 31 participants in the control group and 30 participants in the intervention group. The results of the statistical analysis comparing the two groups showed that the 5-repetition sit-to-stand test was performed significantly faster (P < 0.05) and that the results of the word list memory (WM) test and the Symbol Digit Substitution Task also had significantly improved (P < 0.05) after the intervention in both groups. The WM score did not show an interactive effect between the group and time factors, but it had a significant main effect on time in both groups (P < 0.05). CONCLUSION: The results of our quasi-experimental study indicated that the multicomponent programme based on the ROT would be as effective as the original multicomponent programme combined with aerobic exercise and cognitive tasks, as highlighted in the WM.
Asunto(s)
Cognición , Ejercicio Físico , Anciano , Humanos , Terapia por Ejercicio/métodos , Evaluación Geriátrica , Memoria , Rendimiento Físico FuncionalRESUMEN
Anti-apoptotic Bcl-2-family members not only act at mitochondria but also at the endoplasmic reticulum, where they impact Ca2+ dynamics by controlling IP3 receptor (IP3R) function. Current models propose distinct roles for Bcl-2 vs. Bcl-xL, with Bcl-2 inhibiting IP3Rs and preventing pro-apoptotic Ca2+ release and Bcl-xL sensitizing IP3Rs to low [IP3] and promoting pro-survival Ca2+ oscillations. We here demonstrate that Bcl-xL too inhibits IP3R-mediated Ca2+ release by interacting with the same IP3R regions as Bcl-2. Via in silico superposition, we previously found that the residue K87 of Bcl-xL spatially resembled K17 of Bcl-2, a residue critical for Bcl-2's IP3R-inhibitory properties. Mutagenesis of K87 in Bcl-xL impaired its binding to IP3R and abrogated Bcl-xL's inhibitory effect on IP3Rs. Single-channel recordings demonstrate that purified Bcl-xL, but not Bcl-xLK87D, suppressed IP3R single-channel openings stimulated by sub-maximal and threshold [IP3]. Moreover, we demonstrate that Bcl-xL-mediated inhibition of IP3Rs contributes to its anti-apoptotic properties against Ca2+-driven apoptosis. Staurosporine (STS) elicits long-lasting Ca2+ elevations in wild-type but not in IP3R-knockout HeLa cells, sensitizing the former to STS treatment. Overexpression of Bcl-xL in wild-type HeLa cells suppressed STS-induced Ca2+ signals and cell death, while Bcl-xLK87D was much less effective in doing so. In the absence of IP3Rs, Bcl-xL and Bcl-xLK87D were equally effective in suppressing STS-induced cell death. Finally, we demonstrate that endogenous Bcl-xL also suppress IP3R activity in MDA-MB-231 breast cancer cells, whereby Bcl-xL knockdown augmented IP3R-mediated Ca2+ release and increased the sensitivity towards STS, without altering the ER Ca2+ content. Hence, this study challenges the current paradigm of divergent functions for Bcl-2 and Bcl-xL in Ca2+-signaling modulation and reveals that, similarly to Bcl-2, Bcl-xL inhibits IP3R-mediated Ca2+ release and IP3R-driven cell death. Our work further underpins that IP3R inhibition is an integral part of Bcl-xL's anti-apoptotic function.
Asunto(s)
Apoptosis , Señalización del Calcio , Receptores de Inositol 1,4,5-Trifosfato , Proteína bcl-X , Calcio/metabolismo , Células HeLa , Humanos , Receptores de Inositol 1,4,5-Trifosfato/genética , Proteína bcl-X/metabolismoRESUMEN
The sterile inflammation caused by damage-associated molecular patterns (DAMPs) worsens the prognosis following primary injury such as ischemic stroke. However, there are no effective treatments to regulate DAMPs. Here, we report that AIM (or CD5L) protein reduces sterile inflammation by attenuating DAMPs and that AIM administration ameliorates the deleterious effects of ischemic stroke. AIM binds to DAMPs via charge-based interactions and disulfide bond formation. This AIM association promotes the phagocytic removal of DAMPs and neutralizes DAMPs by impeding their binding to inflammatory receptors. In experimental stroke, AIM-deficient mice exhibit severe neurological damage and higher mortality with greater levels of DAMPs and associated inflammation in the brain than wild-type mice, in which brain AIM levels increase following stroke onset. Recombinant AIM administration reduces sterile inflammation in the infarcted region, leading to a profound reduction of animal mortality. Our findings provide a basis for the therapies targeting DAMPs to improve ischemic stroke.
Asunto(s)
Alarminas/metabolismo , Proteínas Reguladoras de la Apoptosis/metabolismo , Encéfalo/metabolismo , Accidente Cerebrovascular Isquémico/patología , Receptores Depuradores/metabolismo , Animales , Proteínas Reguladoras de la Apoptosis/genética , Encéfalo/patología , Modelos Animales de Enfermedad , Disulfuros/metabolismo , Humanos , Interleucina-1beta/genética , Interleucina-1beta/metabolismo , Interleucina-6/genética , Interleucina-6/metabolismo , Accidente Cerebrovascular Isquémico/tratamiento farmacológico , Accidente Cerebrovascular Isquémico/metabolismo , Accidente Cerebrovascular Isquémico/mortalidad , Macrófagos/citología , Macrófagos/inmunología , Macrófagos/metabolismo , Factor de Transcripción MafB/deficiencia , Factor de Transcripción MafB/genética , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Pronóstico , Unión Proteica , Receptores Depuradores/genética , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/aislamiento & purificación , Proteínas Recombinantes/uso terapéutico , Tasa de SupervivenciaRESUMEN
Contact sites of endoplasmic reticulum (ER) and mitochondria locally convey calcium signals between the IP3 receptors (IP3R) and the mitochondrial calcium uniporter, and are central to cell survival. It remains unclear whether IP3Rs also have a structural role in contact formation and whether the different IP3R isoforms have redundant functions. Using an IP3R-deficient cell model rescued with each of the three IP3R isoforms and an array of super-resolution and ultrastructural approaches we demonstrate that IP3Rs are required for maintaining ER-mitochondrial contacts. This role is independent of calcium fluxes. We also show that, while each isoform can support contacts, type 2 IP3R is the most effective in delivering calcium to the mitochondria. Thus, these studies reveal a non-canonical, structural role for the IP3Rs and direct attention towards the type 2 IP3R that was previously neglected in the context of ER-mitochondrial calcium signaling.
Asunto(s)
Canales de Calcio/metabolismo , Señalización del Calcio/fisiología , Retículo Endoplásmico/metabolismo , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Mitocondrias/metabolismo , Animales , Línea Celular Tumoral , Supervivencia Celular/fisiología , Pollos , Células HeLa , Humanos , Receptores de Inositol 1,4,5-Trifosfato/genética , Isoformas de Proteínas/genéticaRESUMEN
C-H bond cleavage and formation is one of the most essential elementary reactions in organic chemistry. Herein, a heterolytic sp3 C-H bond reductive elimination from hydroxyCp dimethylplatinum(IV) B is reported. Protonation of cyclopentadienone dimethylplatinum(II) A afforded B via the protonation of the ligand. Successive C-H bond formation from the C anion of the methyl group and the H cation of the hydroxyCp group was observed in the presence of carboxylic acids or hydrogen chloride. The reaction was accompanied by the concurrent reduction of Pt(IV) to Pt(II). Experimental and theoretical investigations suggested that the mechanism for the C-H bond formation was acid-mediated metal-ligand cooperative outer-sphere reductive elimination.
RESUMEN
Spinocerebellar ataxia type 29 (SCA29) is autosomal dominant congenital ataxia characterized by early-onset motor delay, hypotonia, and gait ataxia. Recently, heterozygous missense mutations in an intracellular Ca2+ channel, inositol 1,4,5-trisphosphate (IP3) receptor type 1 (IP3R1), were identified as a cause of SCA29. However, the functional impacts of these mutations remain largely unknown. Here, we determined the molecular mechanisms by which pathological mutations affect IP3R1 activity and Ca2+ dynamics. Ca2+ imaging using IP3R-null HeLa cells generated by genome editing revealed that all SCA29 mutations identified within or near the IP3-binding domain of IP3R1 completely abolished channel activity. Among these mutations, R241K, T267M, T267R, R269G, R269W, S277I, K279E, A280D, and E497K impaired IP3 binding to IP3R1, whereas the T579I and N587D mutations disrupted channel activity without affecting IP3 binding, suggesting that T579I and N587D compromise channel gating mechanisms. Carbonic anhydrase-related protein VIII (CA8) is an IP3R1-regulating protein abundantly expressed in cerebellar Purkinje cells and is a causative gene of congenital ataxia. The SCA29 mutation V1538M within the CA8-binding site of IP3R1 completely eliminated its interaction with CA8 and CA8-mediated IP3R1 inhibition. Furthermore, pathological mutations in CA8 decreased CA8-mediated suppression of IP3R1 by reducing protein stability and the interaction with IP3R1. These results demonstrated the mechanisms by which pathological mutations cause IP3R1 dysfunction, i.e., the disruption of IP3 binding, IP3-mediated gating, and regulation via the IP3R-modulatory protein. The resulting aberrant Ca2+ homeostasis may contribute to the pathogenesis of cerebellar ataxia.
Asunto(s)
Receptores de Inositol 1,4,5-Trifosfato/genética , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Degeneraciones Espinocerebelosas/genética , Biomarcadores de Tumor/genética , Biomarcadores de Tumor/metabolismo , Calcio/metabolismo , Células HeLa , Homeostasis , Humanos , Inositol 1,4,5-Trifosfato/metabolismo , Mutación , Neuronas/metabolismo , Unión Proteica , Degeneraciones Espinocerebelosas/metabolismoRESUMEN
The calcium ion (Ca2+) is a ubiquitous intracellular signaling molecule that regulates diverse physiological and pathological processes, including cancer. Increasing evidence indicates that oncogenes and tumor suppressors regulate the Ca2+ transport systems. Inositol 1,4,5-trisphosphate (IP3) receptors (IP3Rs) are IP3-activated Ca2+ release channels located on the endoplasmic reticulum (ER). They play pivotal roles in the regulation of cell death and survival by controlling Ca2+ transfer from the ER to mitochondria through mitochondria-associated ER membranes (MAMs). Optimal levels of Ca2+ mobilization to mitochondria are necessary for mitochondrial bioenergetics, whereas excessive Ca2+ flux into mitochondria causes loss of mitochondrial membrane integrity and apoptotic cell death. In addition to well-known functions on outer mitochondrial membranes, B-cell lymphoma 2 (Bcl-2) family proteins are localized on the ER and regulate IP3Rs to control Ca2+ transfer into mitochondria. Another regulatory protein of IP3R, IP3R-binding protein released with IP3 (IRBIT), cooperates with or counteracts the Bcl-2 family member depending on cellular states. Furthermore, several oncogenes and tumor suppressors, including Akt, K-Ras, phosphatase and tensin homolog (PTEN), promyelocytic leukemia protein (PML), BRCA1, and BRCA1 associated protein 1 (BAP1), are localized on the ER or at MAMs and negatively or positively regulate apoptotic cell death through interactions with IP3Rs and regulation of Ca2+ dynamics. The remodeling of Ca2+ signaling by oncogenes and tumor suppressors that interact with IP3Rs has fundamental roles in the pathology of cancers.
Asunto(s)
Señalización del Calcio/fisiología , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Neoplasias/metabolismo , Animales , Apoptosis/fisiología , HumanosRESUMEN
MicroRNAs (miRNAs) are small, non-coding RNAs that play critical roles in the post-transcriptional regulation of gene expression. Although the molecular mechanisms of the biogenesis and activation of miRNA have been extensively studied, the details of their kinetics within individual living cells remain largely unknown. We developed a novel method for time-lapse imaging of the rapid dynamics of miRNA activity in living cells using destabilized fluorescent proteins (dsFPs). Real-time monitoring of dsFP-based miRNA sensors revealed the duration necessary for miRNA biogenesis to occur, from primary miRNA transcription to mature miRNA activation, at single-cell resolution. Mathematical modeling, which included the decay kinetics of the fluorescence of the miRNA sensors, demonstrated that miRNAs induce translational repression depending on their complementarity with targets. We also developed a dual-color imaging system, and demonstrated that miR-9-5p and miR-9-3p were produced and activated from a common hairpin precursor with similar kinetics, in single cells. Furthermore, a dsFP-based miR-132 sensor revealed the rapid kinetics of miR-132 activation in cortical neurons under physiological conditions. The timescale of miRNA biogenesis and activation is much shorter than the median half-lives of the proteome, suggesting that the degradation rates of miRNA target proteins are the dominant rate-limiting factors for miRNA-mediated gene silencing.
Asunto(s)
MicroARNs/genética , Análisis de la Célula Individual/métodos , Imagen de Lapso de Tiempo/métodos , Regulación de la Expresión Génica , Humanos , Cinética , MicroARNs/biosíntesis , Estabilidad del ARN/genéticaRESUMEN
IRBIT [inositol 1,4,5-trisphosphate receptor (IP3R) binding protein released with inositol 1,4,5-trisphosphate (IP3)] is a multifunctional protein that regulates several target molecules such as ion channels, transporters, polyadenylation complex, and kinases. Through its interaction with multiple targets, IRBIT contributes to calcium signaling, electrolyte transport, mRNA processing, cell cycle, and neuronal function. However, the regulatory mechanism of IRBIT binding to particular targets is poorly understood. Long-IRBIT is an IRBIT homolog with high homology to IRBIT, except for a unique N-terminal appendage. Long-IRBIT splice variants have different N-terminal sequences and a common C-terminal region, which is involved in multimerization of IRBIT and Long-IRBIT. In this study, we characterized IRBIT and Long-IRBIT splice variants (IRBIT family). We determined that the IRBIT family exhibits different mRNA expression patterns in various tissues. The IRBIT family formed homo- and heteromultimers. In addition, N-terminal splicing of Long-IRBIT changed the protein stability and selectivity to target molecules. These results suggest that N-terminal diversity of the IRBIT family and various combinations of multimer formation contribute to the functional diversity of the IRBIT family.
Asunto(s)
Adenosilhomocisteinasa/metabolismo , Lectinas Tipo C/metabolismo , Proteínas de la Membrana/metabolismo , Adenosilhomocisteinasa/genética , Animales , Células COS , Señalización del Calcio , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/metabolismo , Chlorocebus aethiops , Femenino , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Lectinas Tipo C/genética , Proteínas de la Membrana/genética , Ratones Endogámicos C57BL , Ratones Endogámicos ICR , Ratones Noqueados , Isoformas de Proteínas , Estabilidad Proteica , Simportadores de Sodio-Bicarbonato/genética , Simportadores de Sodio-Bicarbonato/metabolismo , Intercambiador 3 de Sodio-Hidrógeno/genética , Intercambiador 3 de Sodio-Hidrógeno/metabolismo , Xenopus laevisRESUMEN
IRBIT is a molecule that interacts with the inositol 1,4,5-trisphosphate (IP3)-binding pocket of the IP3 receptor (IP3R), whereas the antiapoptotic protein, Bcl2l10, binds to another part of the IP3-binding domain. Here we show that Bcl2l10 and IRBIT interact and exert an additive inhibition of IP3R in the physiological state. Moreover, we found that these proteins associate in a complex in mitochondria-associated membranes (MAMs) and that their interplay is involved in apoptosis regulation. MAMs are a hotspot for Ca2+ transfer between endoplasmic reticulum (ER) and mitochondria, and massive Ca2+ release through IP3R in mitochondria induces cell death. We found that upon apoptotic stress, IRBIT is dephosphorylated, becoming an inhibitor of Bcl2l10. Moreover, IRBIT promotes ER mitochondria contact. Our results suggest that by inhibiting Bcl2l10 activity and promoting contact between ER and mitochondria, IRBIT facilitates massive Ca2+ transfer to mitochondria and promotes apoptosis. This work then describes IRBIT as a new regulator of cell death.
Asunto(s)
Apoptosis , Retículo Endoplásmico/metabolismo , Lectinas Tipo C/metabolismo , Proteínas de la Membrana/metabolismo , Mitocondrias/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/antagonistas & inhibidores , Animales , Línea Celular , Humanos , Receptores de Inositol 1,4,5-Trifosfato/antagonistas & inhibidores , Ratones , Unión Proteica , Mapeo de Interacción de ProteínasRESUMEN
Phosphatidylinositol phosphate kinases (PIPKs) are lipid kinases that generate phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2), a critical lipid signaling molecule that regulates diverse cellular functions, including the activities of membrane channels and transporters. IRBIT (IP3R-binding protein released with inositol 1,4,5-trisphosphate) is a multifunctional protein that regulates diverse target proteins. Here, we report that IRBIT forms signaling complexes with members of the PIPK family. IRBIT bound to all PIPK isoforms in heterologous expression systems and specifically interacted with PIPK type Iα (PIPKIα) and type IIα (PIPKIIα) in mouse cerebellum. Site-directed mutagenesis revealed that two conserved catalytic aspartate residues of PIPKIα and PIPKIIα are involved in the interaction with IRBIT. Furthermore, phosphatidylinositol 4-phosphate, Mg2+, and/or ATP interfered with the interaction, suggesting that IRBIT interacts with catalytic cores of PIPKs. Mutations of phosphorylation sites in the serine-rich region of IRBIT affected the selectivity of its interaction with PIPKIα and PIPKIIα. The structural flexibility of the serine-rich region, located in the intrinsically disordered protein region, is assumed to underlie the mechanism of this interaction. Furthermore, in vitro binding experiments and immunocytochemistry suggest that IRBIT and PIPKIα interact with the Na+/HCO3- cotransporter NBCe1-B. These results suggest that IRBIT forms signaling complexes with PIPKIα and NBCe1-B, whose activity is regulated by PI(4,5)P2.
Asunto(s)
Ácido Aspártico , Dominio Catalítico , Lectinas Tipo C/metabolismo , Proteínas de la Membrana/metabolismo , Fosfotransferasas (Aceptor de Grupo Alcohol)/química , Fosfotransferasas (Aceptor de Grupo Alcohol)/metabolismo , Dominios y Motivos de Interacción de Proteínas , Adenosina Trifosfato/metabolismo , Secuencia de Aminoácidos , Animales , Línea Celular , Cerebelo/metabolismo , Secuencia Conservada , Activación Enzimática , Humanos , Inositol 1,4,5-Trifosfato/metabolismo , Lectinas Tipo C/genética , Proteínas de la Membrana/genética , Ratones , Ratones Noqueados , Datos de Secuencia Molecular , Fosforilación , Unión Proteica , Transporte de Proteínas , Ratas , Eliminación de SecuenciaRESUMEN
BACKGROUND: Mutations in the KRAS gene have been identified as negative predictors of response to anti-epidermal growth factor receptor (EGFR) monoclonal antibody therapy by patients with metastatic colorectal cancer (mCRC). However, it has been based on the study of mainly Caucasian mCRC patients. This prospective study investigated the relationship between the mutation status of EGFR-related genes including KRAS and the response rate (RR) to cetuximab plus irinotecan therapy in Japanese mCRC patients. METHODS: Samples taken from 43 chemotherapy-refractory mCRC patients who had undergone cetuximab plus irinotecan therapy at 11 medical centers in Japan were subjected to direct DNA sequencing to determine the KRAS, BRAF, PIK3CA, NRAS, and AKT1 mutation status. The clinical outcome after the treatment was evaluated for each mutation status. RESULTS: KRAS mutations were detected in 31.7% of 41 eligible patients. The RR to cetuximab plus irinotecan therapy was found to be 17.9 and 0% in the KRAS wild-type and mutant subgroups, respectively. CONCLUSION: Despite the identification of a lower-than-expected RR to treatment by the KRAS wild-type subgroup, KRAS mutation status appears to be a useful predictive marker of response to cetuximab plus irinotecan therapy in Japanese mCRC patients.
Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Pulmonares/tratamiento farmacológico , Anciano , Anciano de 80 o más Años , Anticuerpos Monoclonales Humanizados/administración & dosificación , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Camptotecina/administración & dosificación , Camptotecina/análogos & derivados , Cetuximab , Fosfatidilinositol 3-Quinasa Clase I , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/mortalidad , Neoplasias Colorrectales/patología , Análisis Mutacional de ADN , Supervivencia sin Enfermedad , Femenino , GTP Fosfohidrolasas/genética , Humanos , Irinotecán , Estimación de Kaplan-Meier , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/mortalidad , Neoplasias Hepáticas/secundario , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/mortalidad , Neoplasias Pulmonares/secundario , Masculino , Proteínas de la Membrana/genética , Persona de Mediana Edad , Compuestos Organoplatinos/administración & dosificación , Oxaliplatino , Fosfatidilinositol 3-Quinasas/genética , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas B-raf/genética , Proteínas Proto-Oncogénicas p21(ras) , Resultado del Tratamiento , Proteínas ras/genéticaRESUMEN
IRBIT (also called AHCYL1) was originally identified as a binding protein of the intracellular Ca(2+) channel inositol 1,4,5-trisphosphate (IP3) receptor and functions as an inhibitory regulator of this receptor. Unexpectedly, many functions have subsequently been identified for IRBIT including the activation of multiple ion channels and ion transporters, such as the Na(+)/HCO3(-) co-transporter NBCe1-B, the Na(+)/H(+) exchanger NHE3, the Cl(-) channel cystic fibrosis transmembrane conductance regulator (CFTR), and the Cl(-)/HCO3(-) exchanger Slc26a6. The characteristic serine-rich region in IRBIT plays a critical role in the functions of this protein. In this review, we describe the evolution, domain structure, expression pattern, and physiological roles of IRBIT and discuss the potential molecular mechanisms underlying the coordinated regulation of these diverse ion channels/transporters through IRBIT. This article is part of a Special Issue entitled: Calcium signaling in health and disease. Guest Editors: Geert Bultynck, Jacques Haiech, Claus W. Heizmann, Joachim Krebs, and Marc Moreau.
Asunto(s)
Regulador de Conductancia de Transmembrana de Fibrosis Quística/metabolismo , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Lectinas Tipo C/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas de Transporte de Membrana/metabolismo , Simportadores de Sodio-Bicarbonato/metabolismo , Intercambiadores de Sodio-Hidrógeno/metabolismo , Regulador de Conductancia de Transmembrana de Fibrosis Quística/genética , Células Eucariotas/citología , Células Eucariotas/metabolismo , Evolución Molecular , Regulación de la Expresión Génica , Humanos , Receptores de Inositol 1,4,5-Trifosfato/genética , Activación del Canal Iónico , Lectinas Tipo C/genética , Proteínas de la Membrana/genética , Proteínas de Transporte de Membrana/genética , Estructura Secundaria de Proteína , Estructura Terciaria de Proteína , Transducción de Señal , Simportadores de Sodio-Bicarbonato/genética , Intercambiador 3 de Sodio-Hidrógeno , Intercambiadores de Sodio-Hidrógeno/genética , Transportadores de SulfatoRESUMEN
UNLABELLED: Retrospective studies have suggested that UDP-glucuronosyltransferase (UGT)1A1, UGT1A7, and UGT1A9 predict severe toxicity and efficacy of irinotecan-containing regimens. We prospectively evaluated the impact of UGT1A genotypes and haplotypes on severe toxicity and efficacy in patients treated with fluorouracil, leucovorin, and irinotecan combination chemotherapy (FOLFIRI) for metastatic colorectal cancer (mCRC) from the two prospective multicenter phase II studies in Japan. The FLIGHT1 study was a first-line FOLFIRI trial, and FLIGHT2 was a FOLFOX-refractory, second-line FOLFIRI trial. A total of 73 patients agreed to additional analysis, and were genotyped for UGT1A polymorphisms, UGT1A1*28 (TA6>TA7), UGT1A1*6 (211G>A), UGT1A1*27 (686C>A), UGT1A1*60 (-3279T>G), UGT1A1*93 (-3156G>A), UGT1A7 (-57T>G), UGT1A7*3 (387T>G, 622T>C), and UGT1A9*22 (T9>T10). Of 73 patients, 34 developed G3/4 severe hematological toxicities. The toxicities were significantly more frequent in patients with UGT1A1*6 (211A), UGT1A7 (387G), and UGT1A9*22 reference alleles (T9). Haplotype I, which consists of all favorable alleles, was associated with a significant reduction in hematologic toxicity (P = 0.031). In contrast, haplotype II, which contains four high-risk alleles, showed significantly higher hematologic toxicity than the other haplotypes (P = 0.010). Six out of seven patients who were homozygous for UGT1A1*28 or *6 experienced severe hematological toxicity despite the fact that their response rate was not impaired (42.9%). We concluded that UGT1A polymorphisms, especially UGT1A1*6, are important for the prediction of severe toxicity of FOLFIRI in northeast Asian populations. In this regard, haplotype analyses should substantially impact the prediction of severe hematological toxicities of FOLFIRI. ( CLINICAL TRIAL REGISTRATION: UMIN000002388 and UMIN000002476).
Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Camptotecina/análogos & derivados , Neoplasias Colorrectales/tratamiento farmacológico , Glucuronosiltransferasa/genética , Neutropenia/inducido químicamente , Adulto , Anciano , Anciano de 80 o más Años , Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Camptotecina/administración & dosificación , Camptotecina/efectos adversos , Camptotecina/uso terapéutico , Neoplasias Colorrectales/genética , Femenino , Fluorouracilo/administración & dosificación , Fluorouracilo/efectos adversos , Frecuencia de los Genes , Genotipo , Haplotipos/genética , Humanos , Irinotecán , Japón , Leucovorina/administración & dosificación , Leucovorina/efectos adversos , Masculino , Persona de Mediana Edad , Neutropenia/genética , Polimorfismo de Nucleótido Simple , Estudios Prospectivos , UDP Glucuronosiltransferasa 1A9RESUMEN
Neurotrophin-regulated gene expression is believed to play a key role in long-term changes in synaptic structure and the formation of dendritic spines. Brain-derived neurotrophic factor (BDNF) has been shown to induce increases in dendritic spine formation, and this process is thought to function in part by stimulating CREB-dependent transcriptional changes. To identify CREB-regulated genes linked to BDNF-induced synaptogenesis, we profiled transcriptional occupancy of CREB in hippocampal neurons. Interestingly, de novo motif analysis of hippocampal ChIP-Seq data identified a non-canonical CRE motif (TGGCG) that was enriched at CREB target regions and conferred CREB-responsiveness. Because cytoskeletal remodeling is an essential element of the formation of dendritic spines, within our screens we focused our attention on genes previously identified as inhibitors of RhoA GTPase. Bioinformatic analyses identified dozens of candidate CREB target genes known to regulate synaptic architecture and function. We showed that two of these, the RhoA inhibitors Par6C (Pard6A) and Rnd3 (RhoE), are BDNF-induced CREB-regulated genes. Interestingly, CREB occupied a cluster of non-canonical CRE motifs in the Rnd3 promoter region. Lastly, we show that BDNF-stimulated synaptogenesis requires the expression of Par6C and Rnd3, and that overexpression of either protein is sufficient to increase synaptogenesis. Thus, we propose that BDNF can regulate formation of functional synapses by increasing the expression of the RhoA inhibitors, Par6C and Rnd3. This study shows that genome-wide analyses of CREB target genes can facilitate the discovery of new regulators of synaptogenesis.
Asunto(s)
Factor Neurotrófico Derivado del Encéfalo/genética , Proteínas Portadoras/genética , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/genética , Espinas Dendríticas/genética , Hipocampo/metabolismo , Sinapsis/genética , Proteínas de Unión al GTP rho/genética , Proteínas Adaptadoras Transductoras de Señales , Animales , Sitios de Unión , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Proteínas Portadoras/metabolismo , Células Cultivadas , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Espinas Dendríticas/metabolismo , Perfilación de la Expresión Génica , Regulación del Desarrollo de la Expresión Génica , Estudio de Asociación del Genoma Completo , Hipocampo/citología , Hipocampo/crecimiento & desarrollo , Neurogénesis/genética , Regiones Promotoras Genéticas , Unión Proteica , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Ratas , Ratas Sprague-Dawley , Transducción de Señal , Sinapsis/metabolismo , Proteínas de Unión al GTP rho/metabolismo , Proteína de Unión al GTP rhoA/genética , Proteína de Unión al GTP rhoA/metabolismoRESUMEN
BACKGROUND & AIMS: The cyclic adenosine monophosphate (cAMP) and Ca(2+) signaling pathways synergize to regulate many physiological functions. However, little is known about the mechanisms by which these pathways interact. We investigated the synergy between these signaling pathways in mouse pancreatic and salivary gland ducts. METHODS: We created mice with disruptions in genes encoding the solute carrier family 26, member 6 (Slc26a6(-/-) mice) and inositol 1,4,5-triphosphate (InsP3) receptor-binding protein released with InsP3 (Irbit(-/-)) mice. We investigated fluid secretion by sealed pancreatic ducts and the function of Slc26a6 and the cystic fibrosis transmembrane conductance regulator (CFTR) in HeLa cells and in ducts isolated from mouse pancreatic and salivary glands. Slc26a6 activity was assayed by measuring intracellular pH, and CFTR activity was assayed by measuring Cl(-) current. Protein interactions were determined by immunoprecipitation analyses. RESULTS: Irbit mediated the synergistic activation of CFTR and Slc26a6 by Ca(2+) and cAMP. In resting cells, Irbit was sequestered by InsP3 receptors (IP3Rs) in the endoplasmic reticulum. Stimulation of Gs-coupled receptors led to phosphorylation of IP3Rs, which increased their affinity for InsP3 and reduced their affinity for Irbit. Subsequent weak stimulation of Gq-coupled receptors, which led to production of low levels of IP3, caused dissociation of Irbit from IP3Rs and allowed translocation of Irbit to CFTR and Slc26a6 in the plasma membrane. These processes stimulated epithelial secretion of electrolytes and fluid. These pathways were not observed in pancreatic and salivary glands from Irbit(-/-) or Slc26a6(-/-) mice, or in salivary gland ducts expressing mutant forms of IP3Rs that could not undergo protein kinase A-mediated phosphorylation. CONCLUSIONS: Irbit promotes synergy between the Ca(2+) and cAMP signaling pathways in cultured cells and in pancreatic and salivary ducts from mice. Defects in this pathway could be involved in cystic fibrosis, pancreatitis, or Sjögren syndrome.
Asunto(s)
Adenosilhomocisteinasa/fisiología , Calcio/metabolismo , AMP Cíclico/fisiología , Transducción de Señal/fisiología , Animales , Antiportadores/metabolismo , Transporte Biológico , Proteínas Quinasas Dependientes de AMP Cíclico/fisiología , Regulador de Conductancia de Transmembrana de Fibrosis Quística/fisiología , Epitelio/metabolismo , Inositol 1,4,5-Trifosfato/biosíntesis , Receptores de Inositol 1,4,5-Trifosfato/fisiología , Ratones , Conductos Pancreáticos/metabolismo , Fosforilación , Conductos Salivales/metabolismo , Transportadores de SulfatoRESUMEN
Fluid and HCO(3)(-) secretion are fundamental functions of epithelia and determine bodily fluid volume and ionic composition, among other things. Secretion of ductal fluid and HCO(3)(-) in secretory glands is fueled by Na(+)/HCO(3)(-) cotransport mediated by basolateral solute carrier family 4 member 4 (NBCe1-B) and by Cl(-)/HCO(3)(-) exchange mediated by luminal solute carrier family 26, member 6 (Slc26a6) and CFTR. However, the mechanisms governing ductal secretion are not known. Here, we have shown that pancreatic ductal secretion in mice is suppressed by silencing of the NBCe1-B/CFTR activator inositol-1,4,5-trisphosphate (IP(3)) receptor-binding protein released with IP(3) (IRBIT) and by inhibition of protein phosphatase 1 (PP1). In contrast, silencing the with-no-lysine (WNK) kinases and Ste20-related proline/alanine-rich kinase (SPAK) increased secretion. Molecular analysis revealed that the WNK kinases acted as scaffolds to recruit SPAK, which phosphorylated CFTR and NBCe1-B, reducing their cell surface expression. IRBIT opposed the effects of WNKs and SPAK by recruiting PP1 to the complex to dephosphorylate CFTR and NBCe1-B, restoring their cell surface expression, in addition to stimulating their activities. Silencing of SPAK and IRBIT in the same ducts rescued ductal secretion due to silencing of IRBIT alone. These findings stress the pivotal role of IRBIT in epithelial fluid and HCO(3)(-) secretion and provide a molecular mechanism by which IRBIT coordinates these processes. They also have implications for WNK/SPAK kinase-regulated processes involved in systemic fluid homeostasis, hypertension, and cystic fibrosis.
Asunto(s)
Adenosilhomocisteinasa/metabolismo , Regulación de la Expresión Génica , Lectinas Tipo C/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Animales , Regulador de Conductancia de Transmembrana de Fibrosis Quística/metabolismo , Femenino , Silenciador del Gen , Humanos , Péptidos y Proteínas de Señalización Intracelular , Ratones , Antígenos de Histocompatibilidad Menor , Conductos Pancreáticos/metabolismo , Glándula Parótida/metabolismo , Proteína Fosfatasa 1/metabolismo , Simportadores de Sodio-Bicarbonato/metabolismo , Proteína Quinasa Deficiente en Lisina WNK 1RESUMEN
Inositol 1,4,5-trisphosphate (IP(3)) receptors (IP(3)Rs) are IP(3)-gated Ca(2+) release channels localized on intracellular Ca(2+) stores and play a role in the generation of complex patterns of intracellular Ca(2+) signals. We show herein experimental protocols for the identification of associating proteins of IP(3)R isoforms from various cells and tissues using affinity column chromatography and for the specific knockdown of the expression of IP(3)R isoforms and their associating proteins using RNA interference. These methods will provide clues to understand the exact nature of how the signaling complex contributes to the generation of spatio-temporal patterns of intracellular Ca(2+) signals.
Asunto(s)
Receptores de Inositol 1,4,5-Trifosfato/genética , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Proteínas/genética , Proteínas/metabolismo , Interferencia de ARN , Animales , Línea Celular , Humanos , Receptores de Inositol 1,4,5-Trifosfato/aislamiento & purificación , Unión Proteica , Isoformas de Proteínas/genética , Isoformas de Proteínas/aislamiento & purificación , Isoformas de Proteínas/metabolismo , Proteínas/aislamiento & purificaciónRESUMEN
Neurotrophins are growth factors that are important in neuronal development and survival as well as synapse formation and plasticity. Many of the effects of neurotrophins are mediated by changes in protein expression as a result of altered transcription or translation. To determine whether neurotrophins regulate the production of microRNAs (miRNAs), small RNA species that modulate protein translation or mRNA stability, we used deep sequencing to identify BDNF (brain-derived neurotrophic factor)-induced miRNAs in cultured primary cortical mouse neurons. This revealed that the miR-212/132 cluster contained the miRNAs most responsive to BDNF treatment. This cluster was found to produce four miRNAs: miR-132, miR-132*, miR-212 and miR-212*. Using specific inhibitors, mouse models and promoter analysis we have shown that the regulation of the transcription of the miR-212/132 miRNA cluster and the miRNAs derived from it are regulated by the ERK1/2 (extracellular-signal-regulated kinase 1/2) pathway, via both MSK (mitogen and stress-activated kinase)-dependent and -independent mechanisms.