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BACKGROUND AND PURPOSE: Pancreatic islets are modulated by cross-talk among different cell types and paracrine signalling plays important roles in maintaining glucose homeostasis. Urocortin 3 (UCN3) secreted by pancreatic ß cells activates the CRF2 receptor (CRF2R) and downstream pathways mediated by different G protein or arrestin subtypes in δ cells to cause somatostatin (SST) secretion, and constitutes an important feedback circuit for glucose homeostasis. EXPERIMENTAL APPROACH: Here, we used Arrb1-/-, Arrb2-/-, Gsfl/fl and Gqfl/fl knockout mice, the G11-shRNA-GFPfl/fl lentivirus, as well as functional assays and pharmacological characterization to study how the coupling of Gs, G11 and ß-arrestin1 to CRF2R contributed to UCN3-induced SST secretion in pancreatic δ cells. KEY RESULTS: Our study showed that CRF2R coupled to a panel of G protein and arrestin subtypes in response to UCN3 engagement. While RyR3 phosphorylation by PKA at the S156, S2706 and S4697 sites may underlie the Gs-mediated UCN3- CRF2R axis for SST secretion, the interaction of SYT1 with ß-arrestin1 is also essential for efficient SST secretion downstream of CRF2R. The specific expression of the transcription factor Stat6 may contribute to G11 expression in pancreatic δ cells. Furthermore, we found that different UCN3 concentrations may have distinct effects on glucose homeostasis, and these effects may depend on different CRF2R downstream effectors. CONCLUSIONS AND IMPLICATIONS: Collectively, our results provide a landscape view of signalling mediated by different G protein or arrestin subtypes downstream of paracrine UCN3- CRF2R signalling in pancreatic ß-δ-cell circuits, which may facilitate the understanding of fine-tuned glucose homeostasis networks.
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Receptores de Hormona Liberadora de Corticotropina , Transducción de Señal , Somatostatina , Urocortinas , Animales , Masculino , Ratones , Proteínas de Unión al GTP/metabolismo , Ratones Endogámicos C57BL , Ratones Noqueados , Receptores de Hormona Liberadora de Corticotropina/metabolismo , Somatostatina/metabolismo , Células Secretoras de Somatostatina/metabolismo , Urocortinas/metabolismoRESUMEN
Major depressive disorder (MDD) is associated with functional disturbances in subcortical regions. In this naturalistic prospective study (NCT03294525), we aimed to investigate relationships among subcortical functional connectivity (FC), mood symptom profiles and treatment outcome in MDD using multivariate methods. Medication-free participants with MDD (n = 135) underwent a functional magnetic resonance imaging scan at baseline and completed posttreatment clinical assessment after 8 weeks of antidepressant monotherapy. We used partial least squares (PLS) correlation analysis to explore the association between subcortical FC and mood symptom profiles. FC score, reflecting the weighted representation of each individual in this association, was computed. Replication analysis was undertaken in an independent sample (n = 74). We also investigated the relationship between FC score and treatment outcome in the main sample. A distinctive subcortical connectivity pattern was found to be associated with negative affect. In general, higher FC between the caudate, putamen and thalamus was associated with greater negative affect. This association was partly replicated in the independent sample (similarity between the two samples: r = 0.66 for subcortical connectivity, r = 0.75 for mood symptom profile). Lower FC score predicted both remission and response to treatment after 8 weeks of antidepressant monotherapy. The emphasis here on the role of dorsal striatum and thalamus consolidates prior work of subcortical connectivity in MDD. The findings provide insight into the pathogenesis of MDD, linking subcortical FC with negative affect. However, while the FC score significantly predicted treatment outcome, the low odds ratio suggests that finding predictive biomarkers for depression remains an aspiration.
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Trastorno Depresivo Mayor , Humanos , Afecto , Antidepresivos/uso terapéutico , Trastorno Depresivo Mayor/diagnóstico por imagen , Trastorno Depresivo Mayor/tratamiento farmacológico , Estudios Prospectivos , Resultado del TratamientoRESUMEN
BACKGROUND AND AIM: Suicide is nearly always associated with underlying mental disorders. Risk factors for suicide attempts (SAs) in patients with bipolar disorder (BD) misdiagnosed with major depressive disorder (MDD) remain unelucidated. This study was to evaluate the prevalence and clinical risk factors of SAs in Chinese patients with BD misdiagnosed with MDD. METHODS: A total of 1487 patients with MDD from 13 mental health institutions in China were enrolled. Mini International Neuropsychiatric Interview (MINI) was used to identify patients with BD who are misdiagnosed as MDD. The general sociodemographic and clinical data of the patients were collected and MINI suicide module was used to identify patients with SAs in these misdiagnosed patients. RESULTS: In China, 20.6% of patients with BD were incorrectly diagnosed as having MDD. Among these misdiagnosed patients, 26.5% had attempted suicide. These patients tended to be older, had a higher number of hospitalizations, and were more likely to experience frequent and seasonal depressive episodes with atypical features, psychotic symptoms, and suicidal thoughts. Frequent depressive episodes and suicidal thoughts during depression were identified as independent risk factors for SAs. Additionally, significant sociodemographic and clinical differences were found between individuals misdiagnosed with MDD in BD and patients with MDD who have attempted suicide. CONCLUSIONS: This study highlights the importance of accurate diagnosis in individuals with BD and provide valuable insights for the targeted identification and intervention of individuals with BD misdiagnosed as having MDD and those with genuine MDD, particularly in relation to suicidal behavior.
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Trastorno Bipolar , Trastorno Depresivo Mayor , Humanos , Trastorno Depresivo Mayor/diagnóstico , Trastorno Depresivo Mayor/epidemiología , Trastorno Depresivo Mayor/psicología , Trastorno Bipolar/diagnóstico , Trastorno Bipolar/epidemiología , Trastorno Bipolar/psicología , Intento de Suicidio , Prevalencia , Errores DiagnósticosRESUMEN
BACKGROUND: The neural correlate of cognitive deficits in bipolar disorder (BD) is an issue that warrants further investigation. However, relatively few studies have examined the intrinsic functional connectivity (FC) underlying cognitive deficits involving sustained attention and executive function at both the region and network levels, as well as the different relationships between connectivity patterns and cognitive performance, in BD patients and healthy controls (HCs). METHODS: Patients with BD (n = 59) and HCs (n = 52) underwent structural and resting-state functional magnetic resonance imaging and completed the Wisconsin Card Sorting Test (WCST), the continuous performance test and a clinical assessment. A seed-based approach was used to evaluate the intrinsic FC alterations in three core neurocognitive networks (the default mode network [DMN], the central executive network [CEN] and the salience network [SN]). Finally, we examined the relationship between FC and cognitive performance by using linear regression analyses. RESULTS: Decreased FC was observed within the DMN, in the DMN-SN and DMN-CEN and increased FC was observed in the SN-CEN in BD. The alteration direction of regional FC was consistent with that of FC at the brain network level. Decreased FC between the left posterior cingulate cortex and right anterior cingulate cortex was associated with longer WCST completion time in BD patients (but not in HCs). CONCLUSIONS: These findings emphasize the dominant role of the DMN in the psychopathology of BD and provide evidence that cognitive deficits in BD may be associated with aberrant FC between the anterior and posterior DMN.
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Trastorno Bipolar , Humanos , Trastorno Bipolar/complicaciones , Trastorno Bipolar/diagnóstico por imagen , Función Ejecutiva , Vías Nerviosas/diagnóstico por imagen , Imagen por Resonancia Magnética/métodos , Encéfalo/diagnóstico por imagen , Mapeo Encefálico/métodos , CogniciónRESUMEN
A series of di-functional benzoxazine (BZ) monomers was synthesized, specifically the double-decker silsesquioxane (DDSQ) cage structure (DDSQ-BZ). Comparative analyses were conducted between DDSQ-BZ monomers and the most commonly utilized bisphenol A-functionalized bifunctional benzoxazine (BPA-BZ) monomer. DDSQ-BZ compounds possess better thermal properties such as high char yield and high thermal decomposition temperature (Td10) after thermal ring-opening polymerization (ROP) because the inorganic DDSQ cage nanostructure features a nano-reinforcement effect. In addition, blending inorganic DDSQ-BZ compounds with epoxy resin was explored to form organic/inorganic hybrids with enhanced thermal and mechanical properties following thermal ROP. The improvement in mechanical properties is primarily attributed to the network structure formed by the cross-linking between DDSQ-BZ and the epoxy resin during thermal ROP, as well as hydrogen bonding interactions formed between the hydroxyl groups generated during thermal ROP and the Si-O-Si bonds in the DDSQ structure.
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Solid-state nuclear magnetic resonance (SSNMR), a technique capable of studying solid or semisolid biological samples, was first applied to study the cell differentiation and mineralization using the whole-cell sample. Mesenchymal stromal cells (MSCs) with multipotent differentiation capacity were induced to differentiate into osteoblasts. The whole differentiation process, osteoblast mineralization and the mineral maturation, was investigated using SSNMR, providing intact, atomic level information on the cellular mineral structural transformation. Our research indicated the extent of osteoblast mineralization could vary significantly for different cell populations whereas the difference was not easily shown by other means of characterization. The SSNMR spectra revealed hydroxylapatite (or hydroxyapatite [HAP]) formation around 2 to 4 weeks after osteogenic induction for MSCs with a high differentiation potency. The early mineral phase deposit before HAP formation contained a high amount of HPO4 2-. The structures of minerals in the extracellular matrix (ECM) of osteoblasts could evolve for a period of time, even after the incubation of cells has been stopped. This observation was only possible by studying the sample in an intact state, where ECM was not disturbed. These findings improved our understanding of MSCs, which had wide applications in bone regeneration and tissue engineering. Meanwhile, this work demonstrated the advantage of studying these cellular systems as a whole without any mineral extraction, which had been largely overlooked. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Long-chain fatty acids (LCFAs) are not only energy sources but also serve as signaling molecules. GPR120, an LCFA receptor, plays key roles in maintaining metabolic homeostasis. However, whether endogenous ligand-GPR120 circuits exist and how such circuits function in pancreatic islets are unclear. Here, we found that endogenous GPR120 activity in pancreatic δ-cells modulated islet functions. At least two unsaturated LCFAs, oleic acid (OA) and linoleic acid (LA), were identified as GPR120 agonists within pancreatic islets. These two LCFAs promoted insulin secretion by inhibiting somatostatin secretion and showed bias activation of GPR120 in a model system. Compared with OA, LA exerted higher potency in promoting insulin secretion, which is dependent on ß-arrestin2 function. Moreover, GPR120 signaling was impaired in the diabetic db/db model, and replenishing OA and LA improved islet function in both the db/db and streptozotocin-treated diabetic models. Consistently, the administration of LA improved glucose metabolism in db/db mice. Collectively, our results reveal that endogenous LCFA-GPR120 circuits exist and modulate homeostasis in pancreatic islets. The contributions of phenotype differences caused by different LCFA-GPR120 circuits within islets highlight the roles of fine-tuned ligand-receptor signaling networks in maintaining islet homeostasis.
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Diabetes Mellitus , Islotes Pancreáticos , Animales , Diabetes Mellitus/metabolismo , Ácidos Grasos/metabolismo , Homeostasis , Insulina/metabolismo , Islotes Pancreáticos/metabolismo , Ligandos , Ratones , Ratones Endogámicos C57BL , Receptores Acoplados a Proteínas G/metabolismoRESUMEN
Along with functionally intact insulin, diabetes-associated insulin peptides are secreted by ß cells. By screening the expression and functional characterization of olfactory receptors (ORs) in pancreatic islets, we identified Olfr109 as the receptor that detects insulin peptides. The engagement of one insulin peptide, insB:9-23, with Olfr109 diminished insulin secretion through Gi-cAMP signaling and promoted islet-resident macrophage proliferation through a ß cell-macrophage circuit and a ß-arrestin-1-mediated CCL2 pathway, as evidenced by ß-arrestin-1-/- mouse models. Systemic Olfr109 deficiency or deficiency induced by Pdx1-Cre+/-Olfr109fl/fl specifically alleviated intra-islet inflammatory responses and improved glucose homeostasis in Akita- and high-fat diet (HFD)-fed mice. We further determined the binding mode between insB:9-23 and Olfr109. A pepducin-based Olfr109 antagonist improved glucose homeostasis in diabetic and obese mouse models. Collectively, we found that pancreatic ß cells use Olfr109 to autonomously detect self-secreted insulin peptides, and this detection arrests insulin secretion and crosstalks with macrophages to increase intra-islet inflammation.
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Células Secretoras de Insulina , Islotes Pancreáticos , Animales , Glucemia/metabolismo , Dieta Alta en Grasa , Glucosa/metabolismo , Insulina/metabolismo , Células Secretoras de Insulina/metabolismo , Polipéptido Amiloide de los Islotes Pancreáticos/metabolismo , Islotes Pancreáticos/metabolismo , Ratones , Ratones Endogámicos C57BL , Receptores Acoplados a Proteínas G/metabolismoRESUMEN
Pheromone receptors (PRs) recognize specific pheromone compounds to guide the behavioral outputs of insects, which are the most diverse group of animals on earth. The activation of PRs is known to couple to the calcium permeability of their coreceptor (Orco) or putatively with G proteins; however, the underlying mechanisms of this process are not yet fully understood. Moreover, whether this transverse seven transmembrane domain (7TM)-containing receptor is able to couple to arrestin, a common effector for many conventional 7TM receptors, is unknown. Herein, using the PR BmOR3 from the silk moth Bombyx mori and its coreceptor BmOrco as a template, we revealed that an agonist-induced conformational change of BmOR3 was transmitted to BmOrco through transmembrane segment 7 from both receptors, resulting in the activation of BmOrco. Key interactions, including an ionic lock and a hydrophobic zipper, are essential in mediating the functional coupling between BmOR3 and BmOrco. BmOR3 also selectively coupled with Gi proteins, which was dispensable for BmOrco coupling. Moreover, we demonstrated that trans-7TM BmOR3 recruited arrestin in an agonist-dependent manner, which indicates an important role for BmOR3-BmOrco complex formation in ionotropic functions. Collectively, our study identified the coupling of G protein and arrestin to a prototype trans-7TM PR, BmOR3, and provided important mechanistic insights into the coupling of active PRs to their downstream effectors, including coreceptors, G proteins, and arrestin.
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Bombyx , Proteínas de Insectos , Receptores Odorantes , Animales , Bombyx/química , Bombyx/genética , Bombyx/metabolismo , Células HEK293 , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Proteínas de Insectos/química , Proteínas de Insectos/genética , Proteínas de Insectos/metabolismo , Dominios Proteicos , Receptores Odorantes/química , Receptores Odorantes/genética , Receptores Odorantes/metabolismoRESUMEN
The succinate-acetate permease (SatP) is an anion channel with six transmembrane domains. It forms different oligomers, especially hexamers in the detergent as well as in the membrane. Solid-state NMR studies of SatP were carried out successfully on SatP complexes by reconstructing the protein into liposomes or retaining the protein in the native membrane of E. coli., where it was expressed. The comparison of 13C-13C 2D correlation spectra between the two samples showed great similarity, opening the possibility to further study the acetate transport mechanism of SatP in its native membrane environment. Solid-state NMR studies also revealed small chemical shift differences of SatP in the two different membrane systems, indicating the importance of the lipid environment in determining the membrane protein structures and dynamics. Combining different 2D SSNMR spectra, chemical shift assignments were made on some sites, consistent with the helical structures in the transmembrane domains. In the end, we pointed out the limitation in the sensitivity for membrane proteins with such a size, and also indicated possible ways to overcome it.
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OBJECTIVES: Genome-wide analyses of antidepressant response have suggested that genes initially associated with risk for schizophrenia may also serve as promising candidates for selective serotonin reuptake inhibitor (SSRI) efficacy. Protein tyrosine phosphatase, receptor-type, zeta-1 (PTPRZ1) has previously been shown to be associated with schizophrenia, but it has not been investigated as a predictor of antidepressant efficacy. The main objective of the study was to assess whether SSRI-mediated depressive and anxiety symptom remission in Chinese patients with major depressive disorder (MDD) are associated with specific PTPRZ1 variants. METHODS: Two independent cohorts were investigated, the first sample (N = 344) received an SSRI (i.e. fluoxetine, sertraline, citalopram, escitalopram, fluvoxamine, or paroxetine) for 8 weeks. The second sample (N = 160) only received escitalopram for 8 weeks. Hamilton Depression and Hamilton Anxiety Rating Scale scores at 8-weeks post-baseline in both cohorts were used to determine remission status. Five PTPRZ1 variants (rs12154537, rs6466810, rs6466808, rs6955395, and rs1918031) were genotyped in both cohorts. RESULTS: Anxiety symptom remission was robustly associated with PTPRZ1 rs12154537 (P = 0.004) and the G-G-G-G haplotype (rs12154537-rs6466810-rs6466808-rs6955395; P = 0.005) in cohort 2 but not cohort 1 (mixed SSRI use). Associations with depressive symptom remission did not survive correction for multiple testing. CONCLUSIONS: These findings suggest that PTPRZ1 variants may serve as a marker of escitalopram-mediated anxiety symptom remission in MDD.
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Trastorno Depresivo Mayor , Ansiedad/tratamiento farmacológico , Ansiedad/genética , Citalopram/efectos adversos , Trastorno Depresivo Mayor/tratamiento farmacológico , Trastorno Depresivo Mayor/genética , Escitalopram , Variación Genética , Estudio de Asociación del Genoma Completo , Humanos , Proteínas Tirosina Fosfatasas Clase 5 Similares a Receptores , Inhibidores Selectivos de la Recaptación de Serotonina/efectos adversos , Resultado del TratamientoRESUMEN
Arrestins recognize different receptor phosphorylation patterns and convert this information to selective arrestin functions to expand the functional diversity of the G protein-coupled receptor (GPCR) superfamilies. However, the principles governing arrestin-phospho-receptor interactions, as well as the contribution of each single phospho-interaction to selective arrestin structural and functional states, are undefined. Here, we determined the crystal structures of arrestin2 in complex with four different phosphopeptides derived from the vasopressin receptor-2 (V2R) C-tail. A comparison of these four crystal structures with previously solved Arrestin2 structures demonstrated that a single phospho-interaction change results in measurable conformational changes at remote sites in the complex. This conformational bias introduced by specific phosphorylation patterns was further inspected by FRET and 1H NMR spectrum analysis facilitated via genetic code expansion. Moreover, an interdependent phospho-binding mechanism of phospho-receptor-arrestin interactions between different phospho-interaction sites was unexpectedly revealed. Taken together, our results provide evidence showing that phospho-interaction changes at different arrestin sites can elicit changes in affinity and structural states at remote sites, which correlate with selective arrestin functions.
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Receptores de Vasopresinas/metabolismo , beta-Arrestina 1/metabolismo , Cristalografía por Rayos X , Células HEK293 , Humanos , Mutación , Resonancia Magnética Nuclear Biomolecular , Fosfopéptidos/química , Fosfopéptidos/metabolismo , Fosforilación , Conformación Proteica en Hélice alfa , Dominios Proteicos/genética , Receptores de Vasopresinas/química , Receptores de Vasopresinas/ultraestructura , Proteínas Recombinantes/aislamiento & purificación , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/ultraestructura , beta-Arrestina 1/genética , beta-Arrestina 1/aislamiento & purificación , beta-Arrestina 1/ultraestructuraRESUMEN
Bipolar disorder (BD) is a major and highly heritable mental illness with severe psychosocial impairment, but its etiology and pathogenesis remains unclear. This study aimed to identify the essential pathways and genes involved in BD using weighted gene coexpression network analysis (WGCNA), a bioinformatic method studying the relationships between genes and phenotypes. Using two available BD gene expression datasets (GSE5388, GSE5389), we constructed a gene coexpression network and identified modules related to BD. The analyses of Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathways were performed to explore functional enrichment of the candidate modules. A protein-protein interaction (PPI) network was further constructed to identify the potential hub genes. Ten coexpression modules were identified from the top 5,000 genes in 77 samples and three modules were significantly associated with BD, which were involved in several biological processes (e.g., the actin filament-based process) and pathways (e.g., MAPK signaling). Four genes (NOTCH1, POMC, NGF, and DRD2) were identified as candidate hub genes by PPI analysis and CytoHubba. Finally, we carried out validation analyses in a separate dataset, GSE12649, and verified NOTCH1 as a hub gene and the involvement of several biological processes such as actin filament-based process and axon development. Taken together, our findings revealed several candidate pathways and genes (NOTCH1) in the pathogenesis of BD and call for further investigation for their potential research values in BD diagnosis and treatment.
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RIPK3 amyloid complex plays crucial roles during TNF-induced necroptosis and in response to immune defense in both human and mouse. Here, we have structurally characterized mouse RIPK3 homogeneous self-assembly using solid-state NMR, revealing a well-ordered N-shaped amyloid core structure featured with 3 parallel in-register ß-sheets. This structure differs from previously published human RIPK1/RIPK3 hetero-amyloid complex structure, which adopted a serpentine fold. Functional studies indicate both RIPK1-RIPK3 binding and RIPK3 amyloid formation are essential but not sufficient for TNF-induced necroptosis. The structural integrity of RIPK3 fibril with three ß-strands is necessary for signaling. Molecular dynamics simulations with a mouse RIPK1/RIPK3 model indicate that the hetero-amyloid is less stable when adopting the RIPK3 fibril conformation, suggesting a structural transformation of RIPK3 from RIPK1-RIPK3 binding to RIPK3 amyloid formation. This structural transformation would provide the missing link connecting RIPK1-RIPK3 binding to RIPK3 homo-oligomer formation in the signal transduction.
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Amiloide/metabolismo , Amiloide/ultraestructura , Necroptosis/fisiología , Proteína Serina-Treonina Quinasas de Interacción con Receptores/química , Proteína Serina-Treonina Quinasas de Interacción con Receptores/metabolismo , Animales , Benzotiazoles , Supervivencia Celular , Drosophila , Herpesviridae , Humanos , Ratones , Simulación de Dinámica Molecular , Necroptosis/genética , Conformación Proteica , Ratas , Proteína Serina-Treonina Quinasas de Interacción con Receptores/genética , Alineación de Secuencia , Análisis de Secuencia de Proteína , Transducción de SeñalRESUMEN
BACKGROUND: The coronavirus disease 2019 (COVID-19) is not only attacking physical health, but it is also increasing psychological suffering. This study aimed to observe the impact of the COVID-19 pandemic on mental health outcomes among patients with mild to moderate illness in Fangcang shelter hospitals. METHODS: We conducted an observational, cross-sectional study of 129 patients with mild to moderate illness from Jiangxia Fangcang shelter hospitals in Wuhan, China. The participants were assessed by quantifying their symptoms of depression, anxiety, insomnia, and stressful life events and analyzing potential risk factors associated with these symptoms. Using correlation analysis, we examined associations between exposure to COVID-19 and subsequent psychological distress in response to the outbreak. RESULTS: In total, 49.6% of participants had depressive or anxiety symptoms. The depressive and anxiety symptoms were highly related to sleep disturbances and hypochondriasis (all r > 0.50, P < 0.01). The impact of the event was positively related to depressive symptoms, anxiety symptoms, sleep disturbances, hypochondriasis and life events (all r > 0.35, P < 0.01) but was negatively related to psychological resilience (r = -0.41, P < 0.01). The presence of the COVID-19 infection in this setting was associated with increased anxiety, depression and stress levels, and decreased sleep quality, and seriously affected patients' quality of life as well as adversely affecting the course and prognosis of physical diseases. CONCLUSION: The sleep quality, anxiety, and depression of COVID-19 patients in Fangcang shelter hospitals were significantly related to the impact of the epidemic.
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Sustained hyperglycaemia and hyperlipidaemia incur endoplasmic reticulum stress (ER stress) and reactive oxygen species (ROS) overproduction in pancreatic ß-cells. ER stress or ROS causes c-Jun N-terminal kinase (JNK) activation, and the activated JNK triggers apoptosis in different cells. Nuclear receptor subfamily 4 group A member 1 (NR4A1) is an inducible multi-stress response factor. The aim of this study was to explore the role of NR4A1 in counteracting JNK activation induced by ER stress or ROS and the related mechanism. qPCR, Western blotting, dual-luciferase reporter and ChIP assays were applied to detect gene expression or regulation by NR4A1. Immunofluorescence was used to detect a specific protein expression in ß-cells. Our data showed that NR4A1 reduced the phosphorylated JNK (p-JNK) in MIN6 cells encountering ER stress or ROS and reduced MKK4 protein in a proteasome-dependent manner. We found that NR4A1 increased the expression of cbl-b (an E3 ligase); knocking down cbl-b expression increased MKK4 and p-JNK levels under ER stress or ROS conditions. We elucidated that NR4A1 enhanced the transactivation of cbl-b promoter by physical association. We further confirmed that cbl-b expression in ß-cells was reduced in NR4A1-knockout mice compared with WT mice. NR4A1 down-regulates JNK activation by ER stress or ROS in ß-cells via enhancing cbl-b expression.
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Estrés del Retículo Endoplásmico , Células Secretoras de Insulina/metabolismo , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Miembro 1 del Grupo A de la Subfamilia 4 de Receptores Nucleares/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Animales , Línea Celular , Regulación de la Expresión Génica , Peróxido de Hidrógeno/metabolismo , MAP Quinasa Quinasa 4/metabolismo , Ratones , Ratones Noqueados , Modelos Biológicos , Miembro 1 del Grupo A de la Subfamilia 4 de Receptores Nucleares/genética , Fosforilación , Regiones Promotoras Genéticas , Unión Proteica , UbiquitinaciónRESUMEN
Characterization of the dynamic conformational changes in membrane protein signaling complexes by nuclear magnetic resonance (NMR) spectroscopy remains challenging. Here we report the site-specific incorporation of 4-trimethylsilyl phenylalanine (TMSiPhe) into proteins, through genetic code expansion. Crystallographic analysis revealed structural changes that reshaped the TMSiPhe-specific amino-acyl tRNA synthetase active site to selectively accommodate the trimethylsilyl (TMSi) group. The unique up-field 1H-NMR chemical shift and the highly efficient incorporation of TMSiPhe enabled the characterization of multiple conformational states of a phospho-ß2 adrenergic receptor/ß-arrestin-1(ß-arr1) membrane protein signaling complex, using only 5 µM protein and 20 min of spectrum accumulation time. We further showed that extracellular ligands induced conformational changes located in the polar core or ERK interaction site of ß-arr1 via direct receptor transmembrane core interactions. These observations provided direct delineation and key mechanism insights that multiple receptor ligands were able to induce distinct functionally relevant conformational changes of arrestin.
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Arrestina/química , Arrestina/genética , Arrestina/metabolismo , Ligandos , Espectroscopía de Protones por Resonancia Magnética/métodos , Sitios de Unión , Cristalografía por Rayos X , Humanos , Modelos Moleculares , Fenilalanina , Unión Proteica , Conformación Proteica , Receptores Adrenérgicos beta 2/metabolismo , Transducción de Señal , beta-Arrestina 1/química , beta-Arrestina 1/genética , beta-Arrestina 1/metabolismoRESUMEN
BACKGROUND: Patients with major depressive disorder (MDD) are at high risk for suicide. As the worst outcome of MDD and common self-concealment in patients with suicide risk, studies of biomarkers may provide useful tools for suicide prevention and treatment. METHODS: This study recruited 168 patients with MDD from the Objective Diagnostic Markers and Personalized Intervention in MDD patients (ODMPIM), including 50 patients with suicide risk. Based on previous evidence and hypothesis, 23 targeted serum biomarkers involving immune-inflammation, neurotrophins, hypothalamic-pituitary-adrenal (HPA) axis and metabolism, were measured. We used path analysis and principal components analysis (PCA) to clarify the associations among serum biomarkers, childhood adversities, adulthood life events, severity of depression and suicide risk. RESULTS: We identified that patients with suicide risk had a higher level of inflammatory markers in serum than patients without suicide risk (P < 0.001), especially chemokine (C-X-C motif) ligand 1 (CXCL-1). After using the Bonferroni correction, there were no differences in biomarkers related to neurotrophins, HPA-axis and metabolism. In addition, a higher proportion of patients with suicide risk had adulthood adversity (assessed by Life Events Scale) (P = 0.003). Intriguingly, path analysis demonstrated that the association between adulthood adversity and suicide risk mainly depended on severity of depression and inflammatory index. CONCLUSION: This study highlights the possible role of inflammation involved in suicide risk of MDD patients. Inflammatory markers have the potential for early identification and then reducing suicidal behaviors or becoming novel treatment targets in suicide risk management.
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Trastorno Depresivo Mayor , Suicidio , Adulto , Biomarcadores , Niño , Trastorno Depresivo Mayor/epidemiología , Humanos , Inflamación , Estrés PsicológicoRESUMEN
Tissue regeneration, such as pancreatic islet tissue propagation in vitro, could serve as a promising strategy for diabetes therapy and personalised drug testing. However, such a strategy has not been realised yet. Propagation could be divided into two steps, in vitro expansion and repeated passaging. Even the first step of the in vitro islet expansion has not been achieved to date. Here, we describe a method that enables the expansion of islet clusters isolated from pregnant mice or wild-type rats by employing a combination of specific regeneration factors and chemical compounds in vitro. The expanded islet clusters expressed insulin, glucagon and somatostatin, which are markers corresponding to pancreatic ß cells, α cells and δ cells, respectively. These different types of cells grouped together, were spatially organised and functioned similarly to primary islets. Further mechanistic analysis revealed that forskolin in our recipe contributed to renewal and regeneration, whereas exendin-4 was essential for preserving islet cell identity. Our results provide a novel method for the in vitro expansion of islet clusters, which is an important step forward in developing future protocols and media used for islet tissue propagation in vitro. Such method is important for future regenerative diabetes therapies and personalised medicines using large amounts of pancreatic islets derived from the same person.
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Genome-wide association study results have linked ADCK1 genetic variation with paliperidone efficacy in a European cohort. However, the generalizability of this locus to non-European populations is unknown. Han Chinese schizophrenia patients (n = 159) were treated with paliperidone palmitate and symptom severity was assessed over 3 months. Examination of 13 ADCK1 genetic variants revealed two single nucleotide polymorphisms (rs12590199, rs11159291) and one haplotype (rs2364747-rs12590199) associated with paliperidone palmitate response. Future work into ADCK1's function and its potential interaction with paliperidone is warranted.