Risk factors for hospital readmission among patients with cirrhosis and ascites in China: a retrospective observational study.

OBJECTIVE: In this investigation, we aimed to explore risk factors for 90-day hospital readmission among patients with cirrhosis and ascites in an Asian population. METHODS: In this retrospective study, we included consecutive patients diagnosed with cirrhosis and ascites hospitalized in Renji Hospital between 2018 and 2022 to elucidate risk factors for 90-day readmission. We conducted multivariate logistic regression analysis to identify readmission risk factors. RESULTS: We included 265 patients with cirrhosis and ascites. A 43% readmission rate was observed within 90 days. After adjustment for multiple covariates, we found that readmission within 90 days was independently linked to reduced levels of hemoglobin (odds ratio [OR] 0.96, 95% confidence interval [CI] 0.94-0.97) and serum albumin (OR 0.88, 95% CI 0.83-0.93), and higher Model for End-Stage Liver Disease and sodium (MELD-Na) scores (OR 1.04, 95% CI 1.01-1.07) at discharge. CONCLUSIONS: Patients with cirrhosis who have ascites are frequently rehospitalized within 90 days after discharge. Lower hemoglobin or albumin and higher MELD-Na scores at discharge may be the main risk factors for hospital readmission.

Diverse modes of H3K36me3-guided nucleosomal deacetylation by Rpd3S.

Context-dependent dynamic histone modifications constitute a key epigenetic mechanism in gene regulation1-4. The Rpd3 small (Rpd3S) complex recognizes histone H3 trimethylation on lysine 36 (H3K36me3) and deacetylates histones H3 and H4 at multiple sites across transcribed regions5-7. Here we solved the cryo-electron microscopy structures of Saccharomyces cerevisiae Rpd3S in its free and H3K36me3 nucleosome-bound states. We demonstrated a unique architecture of Rpd3S, in which two copies of Eaf3-Rco1 heterodimers are asymmetrically assembled with Rpd3 and Sin3 to form a catalytic core complex. Multivalent recognition of two H3K36me3 marks, nucleosomal DNA and linker DNAs by Eaf3, Sin3 and Rco1 positions the catalytic centre of Rpd3 next to the histone H4 N-terminal tail for deacetylation. In an alternative catalytic mode, combinatorial readout of unmethylated histone H3 lysine 4 and H3K36me3 by Rco1 and Eaf3 directs histone H3-specific deacetylation except for the registered histone H3 acetylated lysine 9. Collectively, our work illustrates dynamic and diverse modes of multivalent nucleosomal engagement and methylation-guided deacetylation by Rpd3S, highlighting the exquisite complexity of epigenetic regulation with delicately designed multi-subunit enzymatic machineries in transcription and beyond.

scRNA-seq profiling of neonatal and adult thymus-derived CD4+ T cells by a T cell origin-time tracing model.

It is well documented that the neonatal thymus-derived (neonatal-TD) regulatory T cells (Treg) are essential to prevent lethal autoimmune diseases and allergies, and neonatal and adult thymus possesses distinct output potentials for naïve T cells, including Treg. However, the molecular features and detailed functional differences between neonatal-TD and adult thymus-derived (adult-TD) T cells in terms of their ability to maintain immune homeostasis during long-term environmental influences are still largely unknown, partially due to the lack of appropriate animal models to precisely trace these cells at specific time points. In this study, neonatal-TD and adult-TD CD4+ T cells from the spleen and Peyer's patches were traced for 9 weeks by a T cell origin-time tracing mouse model and analysed by single-cell RNA sequencing. More Treg but fewer naïve T cells were found in neonatal-TD CD4+ T cells from both tissues than those from adult-TD counterparts. Interestingly, the neonatal-TD Treg in both the spleen and Peyer's patches exhibited augmented expression of Foxp3, Gata3, Ctla4, Icos, Il2ra, Tgfb1, and Nrp1, as well as enriched Gene Ontology terms like T cell activation and tolerance induction, indicating an enhanced immunosuppressive function. These results were further confirmed by flow cytometry analysis and in vitro immune suppression assays. Flow cytometry also revealed a significantly higher proportion of neonatal-TD Treg in total Treg than that of adult-TD counterparts, suggesting the longer lifespan of neonatal-TD Treg. To investigate the intrinsic features of neonatal-TD and adult-TD CD4+ T cells, a shortened tracing time was performed. Surprisingly, the neonatal-TD and adult-TD CD4+ T cells had similar proportions of Treg and did not exhibit significant differences in Foxp3, Gata3, Ctla4, Icos, Il2ra, and Tgfb1 expression levels after tracing for 12 days. On the other hand, neonatal-TD Treg present an increased Nrp1 expression level compared with adult-TD counterparts, indicating the enhanced stability. Together, our work reveals that the neonatal-TD Treg are more immunosuppressive, which is likely shaped primarily by environmental factors.

Postpartum cerebral arterial dissections: Clinical features and treatment.

ABSTRACT: Postpartum cerebral arterial dissections are rare, and the clinical features, diagnosis, and treatment approaches are not clear to many physicians. This study was to investigate the clinical features, diagnosis, and treatment of postpartum cerebral arterial dissections.One patient with postpartum cerebral arterial dissections enrolled in our hospital was analyzed. All patients with postpartum cerebral arterial dissections retrieved from the PubMed were also included in this study and analyzed.A total of 45 patients with postpartum cerebral arterial dissections were retrieved including our case, with an age range of 24 to 44 years (mean 34). Thirty-six (80%) patients were older than 30 years of age (mean 35). There were 17 cases of cesarean section, 14 cases of natural labor, and 14 cases whose delivery modes were not reported. The clinical symptoms included headache in 35 cases (78%) and neck pain in 14 (31%). The symptoms occurred at a mean time of 11 days (range 0-53 days) following delivery. Among 45 patients, arterial dissections involved unilateral carotid or vertebral artery in 29 cases (64%), bilateral carotid or vertebral arteries in 8 (18%), 3 arteries in 3 (7%), and all bilateral carotid and vertebral arteries in 5 (11%). Fourteen (31%) patients were treated with antiplatelet agents, 27 (60%) with anticoagulation, 7 (16%) with both antiplatelet and anticoagulation medications, and only 2 (4%) with stent angioplasty. The prognosis was complete recovery in 30 (86%) patients and mild focal neurological symptoms in 5 (14%).Postpartum cerebral arterial dissections are rare, and correct diagnosis relies on imaging examination. Prognosis is usually favorable in patients with early diagnosis and prompt treatment.

Data of CT bow tie filter profiles from three modern CT scanners.

As one of the key hardware components in Computed Tomography (CT) scanners, a bowtie filter reduces unnecessary radiation dose to the peripheries of a patient and equalizes radiation signal to the detector. Knowledge of the exact profiles from different bowtie filters are critical to model the imaging process of CT scanners and to estimate patient dose. However, bowtie filter profiles remain proprietary to most CT vendors. The data of bowtie profiles reported here were directly measured using a solid-state linear-array detector from three modern CT scanners (GE Revolution, Philips iQon, and Toshiba Aquilion ONE Vision. The detailed method, including associated geometrical calibration and data validation, was previously published. This data article is mainly to present the updated bowtie profile data measured after our previous publication.

Sin1-mediated mTOR signaling in cell growth, metabolism and immune response.

The mammalian target of rapamycin (mTOR) is an evolutionarily conserved Ser/Thr protein kinase with essential cellular function via processing various extracellular and intracellular inputs. Two distinct multi-protein mTOR complexes (mTORC), mTORC1 and mTORC2, have been identified and well characterized in eukaryotic cells from yeast to human. Sin1, which stands for Sty1/Spc1-interacting protein1, also known as mitogen-activated protein kinase (MAPK) associated protein (MAPKAP)1, is an evolutionarily conserved adaptor protein. Mammalian Sin1 interacts with many cellular proteins, but it has been widely studied as an essential component of mTORC2, and it is crucial not only for the assembly of mTORC2 but also for the regulation of its substrate specificity. In this review, we summarize our current knowledge of the structure and functions of Sin1, focusing specifically on its protein interaction network and its roles in the mTOR pathway that could account for various cellular functions of mTOR in growth, metabolism, immunity and cancer.

ProBDNF/p75NTR/sortilin pathway is activated in peripheral blood of patients with alcohol dependence.

Alcohol dependence is a worldwide problem with a great social and economic burden in many countries. A number of studies have suggested that BDNF (mature BDNF) and its precursor (proBDNF) play important roles in the alcohol dependence. However, what roles of the mBDNF/proBDNF pathways play during the pathological process of alcohol dependence are not clearly understood. In our clinical study, peripheral blood was sampled from 30 male patients with alcohol dependence and 50 healthy males (as control). The protein levels of proBDNF, p75NTR, sortilin, mBDNF, TrkB and mRNA levels of BDNF, p75NTR, sortilin, and TrkB were detected in the peripheral blood in our study. We found that the protein levels of proBDNF and p75NTR were increased, but not the sortilin protein level; while the TrkB protein level was decreased in the alcohol dependence patients compared with healthy controls. Moreover, the mRNA levels of p75NTR and sortilin from the lymphocytes were slightly increased; while BDNF and TrkB were significantly decreased. The ELISA results of mBDNF and TrkB were declined in the alcohol dependence group. The levels of mBDNF and TrkB were negatively correlated with the average amount of daily ethanol consumption, and the levels of proBDNF, p75NTR and sortilin were positively correlated with the average amount of ethanol consumption per day. The ratio of proBDNF to mBDNF was altered in alcohol dependence patients. The balance between the proBDNF/p75NTR and mBDNF/TrkB signalling pathways appeared dysregulated in alcohol dependence. Our results suggested that both pathways may participate in the complex processes of alcohol dependence.

Sortilin inhibits amyloid pathology by regulating non-specific degradation of APP.

Amyloid plaque is one of the hallmarks of Alzheimer's disease (AD). The key component beta-amyloid (Aß) is generated via proteolytic processing of amyloid precursor protein (APP). Sortilin (encoded by the gene Sort1) is a vacuolar protein sorting 10 protein domain-containing receptor, which is up-regulated in the brain of AD, colocalizes with amyloid plaques and interacts with APP. However, its role in amyloidogenesis remains unclear. In this study, we first found that the protein level of sortilin was up-regulated in the neocortex of aged (7 and 9months old) but not young (2 and 5months old) AD mice (APP/PS1). 9months old APP/PS1 transgenic mice with Sort1 gene knockout showed increased amyloid pathology in the brain; and this phenotype was rescued by intrahippocampal injection of AAV-hSORT1. Moreover, the 9months old APP/PS1 mice without Sort1 also displayed a decreased number of neurons and increased astrocyte activation in the hippocampus. In addition, the present study showed that the intracellular domain of sortilin was involved in the regulation of the non-specific degradation of APP. Together, our findings indicate that sortilin is a beneficial protein for the reduction of amyloid pathology in APP/PS1 mice by promoting APP degradation.

Sortilin Fragments Deposit at Senile Plaques in Human Cerebrum.

Genetic variations in the vacuolar protein sorting 10 protein (Vps10p) family have been linked to Alzheimer's disease (AD). Here we demonstrate deposition of fragments from the Vps10p member sortilin at senile plaques (SPs) in aged and AD human cerebrum. Sortilin changes were characterized in postmortem brains with antibodies against the extracellular and intracellular C-terminal domains. The two antibodies exhibited identical labeling in normal human cerebrum, occurring in the somata and dendrites of cortical and hippocampal neurons. The C-terminal antibody also marked extracellular lesions in some aged and all AD cases, appearing as isolated fibrils, mini-plaques, dense-packing or circular mature-looking plaques. Sortilin and ß-amyloid (Aß) deposition were correlated overtly in a region/lamina- and case-dependent manner as analyzed in the temporal lobe structures, with co-localized immunofluorescence seen at individual SPs. However, sortilin deposition rarely occurred around the pia, at vascular wall or in areas with typical diffuse Aß deposition, with the labeling not enhanced by section pretreatment with heating or formic acid. Levels of a major sortilin fragment ~15 kDa, predicted to derive from the C-terminal region, were dramatically elevated in AD relative to control cortical lysates. Thus, sortilin fragments are a prominent constituent of the extracellularly deposited protein products at SPs in human cerebrum.

Time-cumulated blood pressure exposure and incident impairment of glucose tolerance and diabetes mellitus.

BACKGROUND: With the marked increase in the prevalence of diabetes mellitus, it was the purpose of our study to assess a potential association of time-cumulated exposure to systolic (CumSBP) and of diastolic blood pressure (CumDBP) with onset of impaired glucose tolerance and diabetes mellitus. METHODS: The prospective investigation included participants of the longitudinal Kailuan Study with three baseline examinations in 2006-2007, 2008-2009 and 2010-2011, re-examination in 2012-2013, and no diabetes mellitus at baseline. Cumulative blood pressure (BP) was calculated as cumBP = [(BP1 + BP2)/2 × time1-2] + [(BP2 + BP3)/2 × time2-3]. Based on cumSBP, the study population was stratified into four groups (cumSBP < 480mmHgxyear;n = 15,339; 480mmHgxyear ≤ cumSBP < 520mmHgxyear;n = 7214; 520mmHgxyears ≤ cumSBP < 560mmHgxyears;n = 5675; and cumSBP ≥ 560mmHgxyears;n = 10,576). RESULTS: After adjusting for demographic, anthropomorphic, biochemical, socioeconomic and lifestyle parameters and as compared with the first group, the second, third and fourth group showed a significantly higher incidence of diabetes (P-trend < 0.001;hazard ratio (HR);95% confidence interval (CI):1.28(1.08,1.51),1.54(1.29,1.84), and 2.33(1.98,2.73), respectively), higher incidence of impairment of glucose tolerance (P-trend < 0.001;HR;95% CI1.17(1.02,1.33), 1.43(1.25,1.64), and 2.09(1.85,2.37), respectively), and higher incidence of diabetes developing out of an impairment of glucose tolerance (P-trend < 0.001;HR;95% CI:1.22(0.97,1.54),1.47(1.16,1.86), and 2.01(1.62,2.50), respectively). An increase in cumSBP by 10 mmHg/year or an increase in cumDBP by 5 mmHg/year was associated with a hazard ratio of incident diabetes of 1.04 (95% CI:1.03,1.04) and 1.02(1.02,1.03), respectively, with a hazard ratio of incident impairment of glucose tolerance of 1.04(95% CI:1.03,1.04) and 1.03(95% CI:1.02,1.03), respectively, and with a hazard ratio of incident diabetes developing from impairment of glucose tolerance of 1.04(95% CI:1.03,1.04) and 1.03(95% CI:1.02,1.03), respectively. CONCLUSIONS: Time-cumulated exposure to elevated blood pressure was significantly associated with an elevated incidence of impaired glucose tolerance and diabetes.

Ideal cardiovascular health and incident hypertension: The longitudinal community-based Kailuan study.

Ideal cardiovascular health (CVH) has been defined by the American Heart Association as the absence of disease and presence of 7 key health factors. Since it is unknown whether cumulative exposure to CVH reduces the risk of developing arterial hypertension, we prospectively examined the potential association between cumulative CVH (cumCVH) score (except for blood pressure metrics) and incident hypertension.Of the 101,510 participants with an age range of 18 to 98 years in this longitudinal community-based Kailuan study, our cohort included those 15,014 participants without hypertension at baseline and who had follow-up examinations 2, 4, and 6 years later. CumCVH was calculated as the summed CVH score for each examination multiplied by the time between the 2 examinations (points × year). Based on the cumCVH score, the study population was stratified into groups of <44 points, 44 to 48 points, 49 to 54 points, 55 to 59 points, and ≥60 points.Incidence of hypertension ranged from 16.76% in the lowest cumCVH category to 11.52% in the highest cumCVH category. After adjusting for age, sex, education level, income level, high-sensitivity C-reactive protein concentration, uric acid concentration, resting heart rate, parental history of hypertension at baseline, and medication usage before the third follow-up examination, participants in the highest cumCVH category had a significantly reduced risk of incident hypertension compared with those in the lowest cumCVH category (adjusted odds ratio 0.60, 95% confidence interval 0.50-0.71). For every increase in category based on the cumCVH score, the risk of hypertension decreased by approximately 2% (odds ratio 0.98, 95% confidence interval 0.97-0.98). The effect was consistent across sex and age groups.A higher cumCVH score is associated with a lower risk of incident hypertension.

ProBDNF Signaling Regulates Depression-Like Behaviors in Rodents under Chronic Stress.

Chronic exposure to stressful environment is a key risk factor contributing to the development of depression. However, the mechanisms involved in this process are still unclear. Brain-derived neurotropic factor (BDNF) has long been investigated for its positive role in regulation of mood, although the role of its precursor, proBDNF, in regulation of mood is not known. In this study, using an unpredictable chronic mild stress (UCMS) paradigm we found that the protein levels of proBDNF were increased in the neocortex and hippocampus of stressed mice and this UCMS-induced upregulation of proBDNF was abolished by chronic administration of fluoxetine. We then established a rat model of UCMS and found that the expression of proBDNF/p75NTR/sortilin was upregulated, whereas the expression of mature BDNF and TrkB was downregulated in both neocortex and hippocampus of chronically stressed rats. Finally, we found that the injection of anti-proBDNF antibody via intracerebroventricular (i.c.v.) and intraperitoneal (i.p.) approaches into the UCMS rats significantly reversed the stress-induced depression-like behavior and restored the exploratory activity and spine growth. Although intramuscular injection of AAV-proBDNF did not exacerbate the UCMS-elicited rat mood-related behavioral or pathological abnormalities, i.c.v. injection of AAV-proBDNF increased the depression-like behavior in naive rats. Our findings suggest that proBDNF plays a role in the development of chronic stress-induced mood disturbances in rodents. Central (i.c.v.) or peripheral (i.p.) inhibition of proBDNF by injecting specific anti-proBDNF antibodies may provide a novel therapeutic approach for the treatment of stress-related mood disorders.

Combinatorial Histone Readout by the Dual Plant Homeodomain (PHD) Fingers of Rco1 Mediates Rpd3S Chromatin Recruitment and the Maintenance of Transcriptional Fidelity.

The plant homeodomain (PHD) finger is found in many chromatin-associated proteins and functions to recruit effector proteins to chromatin through its ability to bind both methylated and unmethylated histone residues. Here, we show that the dual PHD fingers of Rco1, a member of the Rpd3S histone deacetylase complex recruited to transcribing genes, operate in a combinatorial manner in targeting the Rpd3S complex to histone H3 in chromatin. Although mutations in either the first or second PHD finger allow for Rpd3S complex formation, the assembled complexes from these mutants cannot recognize nucleosomes or function to maintain chromatin structure and prevent cryptic transcriptional initiation from within transcribed regions. Taken together, our findings establish a critical role of combinatorial readout in maintaining chromatin organization and in enforcing the transcriptional fidelity of genes.

Mice with Sort1 deficiency display normal cognition but elevated anxiety-like behavior.

Exposure to stressful life events plays a central role in the development of mood disorders in vulnerable individuals. However, the mechanisms that link mood disorders to stress are poorly understood. Brain-derived neurotrophic factor (BDNF) has long been implicated in positive regulation of depression and anxiety, while its precursor (proBDNF) recently showed an opposing effect on such mental illnesses. P75(NTR) and sortilin are co-receptors of proBDNF, however, the role of these receptors in mood regulation is not established. Here, we aimed to investigate the role of sortilin in regulating mood-related behaviors and its role in the proBDNF-mediated mood abnormality in mice. We found that sortilin was up-regulated in neocortex (by 78.3%) and hippocampus (by 111%) of chronically stressed mice as assessed by western blot analysis. These changes were associated with decreased mobility in the open field test and increased depression-like behavior in the forced swimming test. We also found that sortilin deficiency in mice resulted in hyperlocomotion in the open field test and increased anxiety-like behavior in both the open field and elevated plus maze tests. No depression-like behavior in the forced swimming test and no deficit in spatial cognition in the Morris water maze test were found in the Sort1-deficient mice. Moreover, the intracellular and extracellular levels of mature BDNF and proBDNF were not changed when sortilin was absent in vivo and in vitro. Finally, we found that both WT and Sort1-deficient mice injected with proBDNF in lateral ventricle displayed increased depression-like behavior in the forced swimming test but not anxiety-like behaviors in the open field and elevated plus maze tests. The present study suggests that sortilin functions as a negative regulator of mood performance and can be a therapeutic target for the treatment of mental illness.

Homodimeric PHD Domain-containing Rco1 Subunit Constitutes a Critical Interaction Hub within the Rpd3S Histone Deacetylase Complex.

Recognition of histone post-translational modifications is pivotal for directing chromatin-modifying enzymes to specific genomic regions and regulating their activities. Emerging evidence suggests that other structural features of nucleosomes also contribute to precise targeting of downstream chromatin complexes, such as linker DNA, the histone globular domain, and nucleosome spacing. However, how chromatin complexes coordinate individual interactions to achieve high affinity and specificity remains unclear. The Rpd3S histone deacetylase utilizes the chromodomain-containing Eaf3 subunit and the PHD domain-containing Rco1 subunit to recognize nucleosomes that are methylated at lysine 36 of histone H3 (H3K36me). We showed previously that the binding of Eaf3 to H3K36me can be allosterically activated by Rco1. To investigate how this chromatin recognition module is regulated in the context of the Rpd3S complex, we first determined the subunit interaction network of Rpd3S. Interestingly, we found that Rpd3S contains two copies of the essential subunit Rco1, and both copies of Rco1 are required for full functionality of Rpd3S. Our functional dissection of Rco1 revealed that besides its known chromatin-recognition interfaces, other regions of Rco1 are also critical for Rpd3S to recognize its nucleosomal substrates and functionin vivo. This unexpected result uncovered an important and understudied aspect of chromatin recognition. It suggests that precisely reading modified chromatin may not only need the combined actions of reader domains but also require an internal signaling circuit that coordinates the individual actions in a productive way.

Neurotrophin-3 Induces BMP-2 and VEGF Activities and Promotes the Bony Repair of Injured Growth Plate Cartilage and Bone in Rats.

Injured growth plate is often repaired by bony tissue causing bone growth defects, for which the mechanisms remain unclear. Because neurotrophins have been implicated in bone fracture repair, here we investigated their potential roles in growth plate bony repair in rats. After a drill-hole injury was made in the tibial growth plate and bone, increased injury site mRNA expression was observed for neurotrophins NGF, BDNF, NT-3, and NT-4 and their Trk receptors. NT-3 and its receptor TrkC showed the highest induction. NT-3 was localized to repairing cells, whereas TrkC was observed in stromal cells, osteoblasts, and blood vessel cells at the injury site. Moreover, systemic NT-3 immunoneutralization reduced bone volume at injury sites and also reduced vascularization at the injured growth plate, whereas recombinant NT-3 treatment promoted bony repair with elevated levels of mRNA for osteogenic markers and bone morphogenetic protein (BMP-2) and increased vascularization and mRNA for vascular endothelial growth factor (VEGF) and endothelial cell marker CD31 at the injured growth plate. When examined in vitro, NT-3 promoted osteogenesis in rat bone marrow stromal cells, induced Erk1/2 and Akt phosphorylation, and enhanced expression of BMPs (particularly BMP-2) and VEGF in the mineralizing cells. It also induced CD31 and VEGF mRNA in rat primary endothelial cell culture. BMP activity appears critical for NT-3 osteogenic effect in vitro because it can be almost completely abrogated by co-addition of the BMP inhibitor noggin. Consistent with its angiogenic effect in vivo, NT-3 promoted angiogenesis in metatarsal bone explants, an effect abolished by co-treatment with anti-VEGF. This study suggests that NT-3 may be an osteogenic and angiogenic factor upstream of BMP-2 and VEGF in bony repair, and further studies are required to investigate whether NT-3 may be a potential target for preventing growth plate faulty bony repair or for promoting bone fracture healing. © 2016 American Society for Bone and Mineral Research.

Multimodality Imaging in Pediatric Osteosarcoma in the Era of Image Gently and Image Wisely Campaign With a Close Look at the CT Scan Radiation Dose.

The increasing use of serial multimodality imaging in the management of pediatric osteosarcoma raises concern of over exposure to ionizing radiation in children, especially from repeated computed tomographic (CT) scans. This study reviews the utilization of multimodality imaging in patients with osteosarcoma at our institution and analyzes any potential radiation-related complications. Twenty-eight patients were identified. Three patients developed late complications-acute myeloid leukemia, myelodysplastic syndrome, and early menopause. Using the patient's age and body part imaged, CT dose length product and effective dose was estimated with the use of a conversion factor for 19 patients. The effective doses were higher in the 3 patients with late complications than the other patients in the cohort (P=0.018). These results suggest an increased risk for adverse effects with higher CT exposures and effective doses. On the basis of our data and published data, methods to decrease the doses of radiation from medical imaging need to be explored. The number of CT scans may be limited. Implementing the Image Gently concept to decrease radiation exposure can be beneficial in modification of CT acquisition parameters.

Nucleosome contact triggers conformational changes of Rpd3S driving high-affinity H3K36me nucleosome engagement.

The Rpd3S histone deacetylase complex utilizes two subunits, Eaf3 and Rco1, to recognize nucleosomes methylated at H3K36 (H3K36me) with high affinity and strong specificity. However, the chromobarrel domain of Eaf3 (CHD) that is responsible for H3K36me recognition only binds weakly and with little specificity to histone peptides. Here, using deuterium exchange mass spectrometry (DXMS), we detected conformational changes of Rpd3S upon its contact with chromatin. Interestingly, we found that the Sin3-interacting domain of Rco1 (SID) allosterically stimulates preferential binding of Eaf3 to H3K36-methylated peptides. This activation is tightly regulated by an autoinhibitory mechanism to ensure optimal multivalent engagement of Rpd3S with nucleosomes. Lastly, we identified mutations at the interface between SID and Eaf3 that do not disrupt complex integrity but severely compromise Rpd3S functions in vitro and in vivo, suggesting that the nucleosome-induced conformational changes are essential for chromatin recognition.

Deletion of TRIM32 protects mice from anxiety- and depression-like behaviors under mild stress.

Chronic stress causes a variety of psychiatric disorders such as anxiety and depression, but its mechanism is not well understood. Tripartite motif-containing protein 32 (TRIM32) was strongly associated with autism spectrum disorder, attention deficit hyperactivity disorder, anxiety and obsessive compulsive disorder based on a study of copy number variation, and deletion of TRIM32 increased neural proliferation and reduced apoptosis. Here, we propose that TRIM32 is involved in chronic stress-induced affective behaviors. Using a chronic unpredictable mild stress mouse depression model, we studied expression of TRIM32 in brain tissue samples and observed behavioral changes in Trim32 knockout mice. The results showed that TRIM32 protein but not its mRNA was significantly reduced in hippocampus in a time-dependent manner within 8 weeks of chronic stress. These stress-induced affective behaviors and reduction of TRIM32 protein expression were significantly reversed by antidepressant fluoxetine treatment. In addition, Trim32 knockout mice showed reduced anxiety and depressive behaviors and hyperactivities compared with Trim32 wild-type mice under normal and mild stress conditions. We conclude that TRIM32 plays important roles in regulation of hyperactivities and positively regulates the development of anxiety and depression disorders induced by chronic stress.

Rapid analysis of aflatoxins B1, B2, and ochratoxin A in rice samples using dispersive liquid-liquid microextraction combined with HPLC.

A novel, simple, and rapid method is presented for the analysis of aflatoxin B1, aflatoxin B2, and ochratoxin A in rice samples by dispersive liquid-liquid microextraction combined with LC and fluorescence detection. After extraction of the rice samples with a mixture of acetonitrile/water/acetic acid, mycotoxins were rapidly partitioned into a small volume of organic solvent (chloroform) by dispersive liquid-liquid microextraction. The three mycotoxins were simultaneously determined by LC with fluorescence detection after precolumn derivatization for aflatoxin B1 and B2. Parameters affecting both extraction and dispersive liquid-liquid microextraction procedures, including the extraction solvent, the type and volume of extractant, the volume of dispersive solvent, the addition of salt, the pH and the extraction time, were optimized. The optimized protocol provided an enrichment factor of approximately 1.25 and with detection of limits (0.06-0.5 µg/kg) below the maximum levels imposed by current regulations for aflatoxins and ochratoxin A. The mean recovery of three mycotoxins ranged from 82.9-112%, with a RSD less than 7.9% in all cases. The method was successfully applied to measure mycotoxins in commercial rice samples collected from local supermarkets in China.