Nuclear corepressors NCOR1 and NCOR2 entrain thymocyte signaling, selection, and emigration

T cell development proceeds via discrete stages that require both gene induction and gene repression. Transcription factors direct gene repression by associating with corepressor complexes containing chromatin-remodeling enzymes; the corepressors NCOR1 and NCOR2 recruit histone deacetylases to these complexes to silence transcription of target genes. Earlier work identified the importance of NCOR1 in promoting the survival of positively-selected thymocytes. Here, we used flow cytometry and single-cell RNA sequencing to identify a broader role for NCOR1 and NCOR2 in regulating thymocyte development. Using Cd4-cre mice, we found that conditional deletion of NCOR2 had no effect on thymocyte development, whereas conditional deletion of NCOR1 had a modest effect. In contrast, Cd4-cre x Ncor1f/f x Ncor2f/f mice exhibited a significant block in thymocyte development at the DP to SP transition. Combined NCOR1/2 deletion resulted in increased signaling through the T cell receptor, ultimately resulting in elevated BIM expression and increased negative selection. The NF-κB, NUR77, and MAPK signaling pathways were also upregulated in the absence of NCOR1/2, contributing to altered CD4/CD8 lineage commitment, TCR rearrangement, and thymocyte emigration. Taken together, our data identify multiple critical roles for the combined action of NCOR1 and NCOR2 over the course of thymocyte development.

Association of beta-blockers or inhibitors of renin-angiotensin system with clinical outcomes in patients with mid-range left ventricular ejection fraction after acute myocardial infarction

Background

In the era of the initial optimal interventional and medical therapy for acute myocardial infarction (AMI), a number of patients with mid-range left ventricular ejection fraction (EF) (>40%, <50%) becomes increasing.

Purpose

This observational study aimed to investigate the association between oral beta-blockers or inhibitors of renin-angiotensin system (RAS) and 2-year clinical outcomes in patients with mid-range EF after AMI.

Methods

Among 13,624 patients enrolled in the Korea Acute Myocardial Infarction Registry-National Institute of Health (KAMIR-NIH), propensity-score matched patients who survived the initial attack and had mid-range EF were selected according to beta-blocker or RAS inhibitor therapy at discharge.

Results

Beta-blocker therapy at discharge was associated with lower 2-year major adverse cardiac events (MACE) of cardiac death, MI, revascularization or re-hospitalization due to heart failure (8.7 vs. 12.8/100 person-year; hazard ratio [HR] 0.68; 95% confidence interval [CI] 0.50–0.93; P=0.015), and no significant interaction between EF ≤45% and >45% was observed (P for interaction=0.354). This association was mainly driven by lower MI in patients with beta-blockers (1.6 vs. 3.1/100 person-year; HR 0.50; 95% CI 0.26–0.95; P=0.035). Inhibitors of RAS at discharge were not associated with lower 2-year MACE, but with lower re-hospitalization due to heart failure (1.8 vs. 3.5/100 person-year; HR 0.53; 95% CI 0.33–0.86; P=0.010) without significant interaction between EF ≤45% and >45% (P for interaction=0.333).

Conclusions

Beta-blockers or RAS inhibitors at discharge were associated with better 2-year clinical outcomes without significant interaction between ≤45% and >45% in patients with mid-range EF after AMI.</ef<50%)>

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Korea Centers for Disease Control and Prevention. 2-year clinical outcomes

Health-related quality of life in patients with a germline BRCA mutation and metastatic pancreatic cancer receiving maintenance olaparib

BACKGROUND

Patients with metastatic pancreatic cancer often have a detriment in health-related quality of life (HRQoL). In the randomized, double-blind, phase III POLO trial progression-free survival was significantly longer with maintenance olaparib, a poly(ADP-ribose) polymerase inhibitor, than placebo in patients with a germline BRCA1 and/or BRCA2 mutation (gBRCAm) and metastatic pancreatic cancer whose disease had not progressed during first-line platinum-based chemotherapy. The prespecified HRQoL evaluation is reported here.

PATIENTS AND METHODS

Patients were randomized to receive maintenance olaparib (300 mg b.i.d.; tablets) or placebo. HRQoL was assessed using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30-item module at baseline, every 4 weeks until disease progression, at discontinuation, and 30 days after last dose. Scores ranged from 0 to 100; a ≥10-point change or difference between arms was considered clinically meaningful. Adjusted mean change from baseline was analysed using a mixed model for repeated measures. Time to sustained clinically meaningful deterioration (TSCMD) was analysed using a log-rank test.

RESULTS

Of 154 randomized patients, 89 of 92 olaparib-arm and 58 of 62 placebo-arm patients were included in HRQoL analyses. The adjusted mean change in Global Health Status (GHS) score from baseline was <10 points in both arms and there was no significant between-group difference [-2.47; 95% confidence interval (CI) -7.27, 2.33; P = 0.31]. Analysis of physical functioning scores showed a significant between-group difference (-4.45 points; 95% CI -8.75, -0.16; P = 0.04). There was no difference in TSCMD for olaparib versus placebo for GHS [P = 0.25; hazard ratio (HR) 0.72; 95% CI 0.41, 1.27] or physical functioning (P = 0.32; HR 1.38; 95% CI 0.73, 2.63).

CONCLUSIONS

HRQoL was preserved with maintenance olaparib treatment with no clinically meaningful difference compared with placebo. These results support the observed efficacy benefit of maintenance olaparib in patients with a gBRCAm and metastatic pancreatic cancer.

CLINCALTRIALS.GOV NUMBER

NCT02184195.

Tetrahydrocannabinol Reduces Hapten-Driven Mast Cell Accumulation and Persistent Tactile Sensitivity in Mouse Model of Allergen-Provoked Localized Vulvodynia

Vulvodynia is a remarkably prevalent chronic pain condition of unknown etiology. An increase in numbers of vulvar mast cells often accompanies a clinical diagnosis of vulvodynia and a history of allergies amplifies the risk of developing this condition. We previously showed that repeated exposures to oxazolone dissolved in ethanol on the labiar skin of mice led to persistent genital sensitivity to pressure and a sustained increase in labiar mast cells. Here we sensitized female mice to the hapten dinitrofluorobenzene (DNFB) dissolved in saline on their flanks, and subsequently challenged them with the same hapten or saline vehicle alone for ten consecutive days either on labiar skin or in the vaginal canal. We evaluated tactile ano-genital sensitivity, and tissue inflammation at serial timepoints. DNFB-challenged mice developed significant, persistent tactile sensitivity. Allergic sites showed mast cell accumulation, infiltration of resident memory CD8⁺CD103⁺ T cells, early, localized increases in eosinophils and neutrophils, and sustained elevation of serum Immunoglobulin E (IgE). Therapeutic intra-vaginal administration of Δ⁹-tetrahydrocannabinol (THC) reduced mast cell accumulation and tactile sensitivity. Mast cell-targeted therapeutic strategies may therefore provide new ways to manage and treat vulvar pain potentially instigated by repeated allergenic exposures.

A high-resolution anorectal manometry parameter based on integrated pressurized volume: A study based on 204 male patients with constipation and 26 controls

BACKGROUND

Conventional anorectal manometric parameters based on linear waves cannot properly predict balloon expulsion (BE) time. We aimed to determine the correlation between integrated pressurized volume (IPV) parameters during simulated evacuation (SE) and BE time in healthy individuals and constipated patients and to assess the correlation between each parameter and symptoms.

METHODS

A total of 230 male participants (including 26 healthy volunteers and 204 chronically constipated patients) underwent high-resolution anorectal manometry (HRAM) and BE tests. The IPV was calculated by multiplying the amplitude, distance, and time from the HRAM profile. Receiver operating characteristic curve (ROC) analysis and partial least square regression (PLSR) were performed.

KEY RESULTS

ROC analysis indicated that the IPV ratio between the upper 1 cm and lower 4 cm of the anal canal was more effective for predicting BE time (area under the curve [AUC]: 0.74, 95% confidence interval [CI]: 0.67-0.80, P < .01) than the conventional anorectal parameters, including defecation index and rectoanal gradient (AUC: 0.60, 95% CI: 0.52-0.67, P = .01). PLSR analysis of a linear combination of IPV parameters yielded an AUC of 0.79. Moreover, the IPV ratio showed a greater clinical correlation with patient symptoms than conventional parameters.

CONCLUSIONS AND INFERENCES

The IPV parameters and the combination of IPV parameters via PLSR were more significantly correlated with BE time than the conventional parameters. Thus, this study presents a useful diagnostic tool for the evaluation of pathophysiologic abnormalities in dyssynergic defecation using IPV and BE time.

Should erectile dysfunction be considered as a marker for acute myocardial infarction? Results from a retrospective cohort study

The association between erectile dysfunction (ED) and acute myocardial infarction (AMI) among men was examined in the Integrated Healthcare Information Services National Managed Care Benchmark Database (IHCIS). The IHCIS is a fully de-identified, HIPAA-compliant database and includes complete medical history for more than 17 million managed care lives; data from more than 30 US health plans, covering seven census regions; and patient demographics, including morbidity, age and gender. A total of 12,825 ED patients and an equal number of male patients without ED were included in the retrospective cohort study. Logistic regression analyses were performed to assess the adjusted risk of AMI that accounted for age at ED diagnosis, smoking, obesity and medications including ACE inhibitors, beta blockers and statins. The cohort of men with ED were observed to have a two-fold increase in the risk for AMI (OR=1.99, 95% CI=1.17, 3.38) after adjusting for age at ED diagnosis, smoking, obesity, and use of ACE inhibitors, beta blockers and statins. Some evidence of a possible trend toward increased risk was detected by age group. After controlling for the aforementioned covariates and compared to men 30-39 y of age, it was noted that patients 40-44 y of age were 3.8 times more likely to develop an AMI (OR=3.76, 95% CI=1.21, 11.7), 45- to 49-y-old men were also more than three times as likely to have an AMI (OR=3.14, 95% CI=1.03, 9.64), and 50- to 55-y-old patients had a four-fold increased risk of developing AMI (OR=4.04, 95% CI=1.39, 11.7). The risk becomes more pronounced with increasing age, indicating the need for cardiologists and internists to monitor ED patients who may not necessarily present with cardiovascular symptoms.

Is erectile dysfunction predictive of peripheral vascular disease?

The association between erectile dysfunction (ED) and peripheral vascular disease (PVD) among men was examined in the Integrated Healthcare Information Services National Managed Care Benchmark Database (IHCIS). The IHCIS is a fully de-identified, Health Insurance Portability and Accountability Act compliant database and includes complete medical histories for more than 17 million managed-care lives; data from more than 30 US health plans, covering seven census regions; and patient demographics, including morbidity, age and gender. A total of 12 825 ED patients and an equal number of male patients without ED were included in the retrospective cohort study. Logistic regression analyses were performed to assess the adjusted risk of PVD that accounted for age at ED diagnosis, smoking, obesity and medications including angiotensin converting enzyme (ACE) inhibitors, beta blockers and statins. The cohort of men with ED were observed to have a 75% increase in risk for PVD (odds ratio (OR) = 1.75, 95% confidence interval (CI) = 1.06, 2.90) after adjusting for age at ED diagnosis, smoking, obesity and use of ACE inhibitors, beta blockers and statins. Some evidence of a possible trend towards increased risk was detected by age group. After controlling for the aforementioned covariates and compared to men aged 30-39 years, it was noted that patients aged 40-44 years were 2.1 times more likely to develop PVD (OR = 2.07, 95% CI = 0.89, 4.81), 45-49-year-old men were also more than twice as likely to have PVD (OR = 2.32, 95% CI = 1.03, 5.22), and 50-55-year-old patients had a three-fold increased risk of developing PVD (OR = 3.00, 95% CI = 1.40, 6.43). The results of this study indicate that ED may serve as a marker for PVD. The risk becomes more pronounced with increasing age, indicating the need for cardiologists and internists to monitor ED patients who may not necessarily present with cardiovascular symptoms.

A novel member of murine Polycomb-group proteins, Sex comb on midleg homolog protein, is highly conserved, and interacts with RAE28/mph1 in vitro

The Polycomb group of (PcG) genes were originally described in Drosophila, but many PcG genes have mammalian homologs. Genetic studies in flies and mice show that mutations in PcG genes cause posterior transformations caused by failure to maintain repression of homeotic loci, suggesting that PcG proteins have conserved functions. The Drosophila gene Sex comb on midleg (Scm) encodes an unusual PcG protein that shares motifs with the PcG protein polyhomeotic, and with a Drosophila tumor suppressor, lethal(3)malignant brain tumor (l(3)mbt). Expressed sequence tag (EST) databases were searched to recover putative mammalian Scm homologs, which were used to screen murine cDNA libraries. The recovered cDNA encodes two mbt repeats and the SPM domain that characterize Scm, but lacks the cysteine clusters and the serine/threonine-rich region found at the amino terminus of Scm. Accordingly, we have named the gene Sex comb on midleg homolog 1 (Scmh1). Like their Drosophila counterparts, Scmh1 and the mammalian polyhomeotic homolog RAE28/mph1 interact in vitro via their SPM domains. We analyzed the expression of Scmh1 and rae28/mph1 using northern analysis of embryos and adult tissues, and in situ hybridization to embryos. The expression of Scmh1 and rae28/mph1 is well correlated in most tissues of embryos. However, in adults, Scmh1 expression was detected in most tissues, whereas mph1/rae28 expression was restricted to the gonads. Scmh1 is strongly induced by retinoic acid in F9 and P19 embryonal carcinoma cells. Scmh1 maps to 4D1-D2.1 in mice. These data suggest that Scmh1 will have an important role in regulation of homeotic genes in embryogenesis and that the interaction with RAE28/mph1 is important in vivo.

Auxin and brassinosteroid differentially regulate the expression of three members of the 1-aminocyclopropane-1-carboxylate synthase gene family in mung bean (Vigna radiata L.)

Indole-3-acetic acid (IAA) markedly increased ethylene production by inducing the expression of three 1aminocyclopropane-1-carboxylate (ACC) synthase cDNAs (pVR-ACS1, pVR-ACS6 and pVR-ACS7) in mung bean hypocotyls. Results from nuclear run-on transcription assay and RNA gel blot studies revealed that all three genes were transcriptionally active displaying unique patterns of induction by IAA and various hormones in etiolated hypocotyls. Particularly, 24-epibrassinolide (BR), an active brassinosteroid, specifically enhanced the expression of VR-ACS7 by a distinct temporal induction mechanism compared to that of IAA. In addition, BR synergistically increased the IAA-induced VR-ACS6 and VR-ACS7 transcript levels, while it effectively abolished both the IAA- and kinetin-induced accumulation of VR-ACS1 mRNA. In light-grown plants, VR-ACS1 was induced by IAA in roots, and VR-ACS6 in epicotyls. IAA- and BR-treatments were not able to increase the VR-ACS7 transcript in the light-grown tissues. These results indicate that the expression of ACC synthase multigene family is regulated by complex hormonal and developmental networks in a gene- and tissue-specific manner in mung bean plants. The VR-ACS7 gene was isolated, and chimeric fusion between the 2.4 kb 5'-upstream region and the beta-glucuronidase (GUS) reporter gene was constructed and introduced into Nicotiana tabacum. Analysis of transgenic tobacco plants revealed the VR-ACS7 promoter-driven GUS activity at a highly localized region of the hypocotyl-root junction of control seedlings, while a marked induction of GUS activity was detected only in the hypocotyl region of the IAA-treated transgenic seedlings where rapid cell elongation occurs. Although there was a modest synergistic effect of BR on the IAA-induced GUS activity, BR alone failed to increase the GUS activity, suggesting that induction of VR-ACS7 occurs via separate signaling pathways in response to IAA and BR. A scheme of the multiple regulatory pathways for the expression of ACC synthase multigene family by auxin and BR is presented.

Roles of active site aromatic residues in catalysis by ketosteroid isomerase from Pseudomonas putida biotype B

The aromatic residues Phe-54, Phe-82, and Trp-116 in the hydrophobic substrate-binding pocket of Delta(5)-3-ketosteroid isomerase from Pseudomonas putida biotype B have been characterized in their roles in steroid binding and catalysis. Kinetic and equilibrium binding analyses were carried out for the mutant enzymes with the substitutions Phe-54 --> Ala or Leu, Phe-82 --> Ala or Leu, and Trp-116 --> Ala, Phe, or Tyr. The removal of their bulky, aromatic side chains at any of these three positions results in reduced k(cat), particularly when Phe-82 or Trp-116 is replaced by Ala. The results are consistent with the binding interactions of the aromatic residues with the bound steroid contributing to catalysis. All the mutations except the F82A mutation increase K(m); the F82A mutation decreases K(m) by ca. 3-fold, suggesting a possibility that the phenyl ring at position 82 might be unfavorable for substrate binding. The K(D) values for d-equilenin, an intermediate analogue, suggest that a space-filling hydrophobic side chain at position 54, a phenyl ring at position 82, and a nonpolar aromatic or small side chain at position 116 might be favorable for binding the reaction intermediate. In contrast to the increased K(D) for equilenin, the enzymes with any substitutions at positions 54 and 116 display a decreased K(D) for 19-nortestosterone, a product analogue, indicating that Phe-54 and Trp-116 might be unfavorable for product binding. The crystal structure of F82A determined to 2.1-A resolution reveals that Phe-82 is important for maintaining the active site geometry. Taken together, our results demonstrate that Phe-54, Phe-82, and Trp-116 contribute differentially to the stabilization of steroid species including substrate, intermediate, and product.

Mutational analysis of the three cysteines and active-site aspartic acid 103 of ketosteroid isomerase from Pseudomonas putida biotype B

In order to clarify the roles of three cysteines in ketosteroid isomerase (KSI) from Pseudomonas putida biotype B, each of the cysteine residues has been changed to a serine residue (C69S, C81S, and C97S) by site-directed mutagenesis. All cysteine mutations caused only a slight decrease in the k(cat) value, with no significant change of Km for the substrate. Even modification of the sulfhydryl group with 5,5'-dithiobis(2-nitrobenzoic acid) has almost no effect on enzyme activity. These results demonstrate that none of the cysteines in the KSI from P. putida is critical for catalytic activity, contrary to the previous identification of a cysteine in an active-site-directed photoinactivation study of KSI. Based on the three-dimensional structures of KSIs with and without dienolate intermediate analog equilenin, as determined by X-ray crystallography at high resolution, Asp-103 was found to be located within the range of the hydrogen bond to the equilenin. To assess the role of Asp-103 in catalysis, Asp-103 has been replaced with either asparagine (D103N) or alanine (D103A) by site-directed mutagenesis. For D103A mutant KSI there was a significant decrease in the k(cat) value: the k(cat) of the mutant was 85-fold lower than that of the wild-type enzyme; however, for the D103N mutant, which retained some hydrogen bonding capability, there was a minor decrease in the k(cat) value. These findings support the idea that aspartic acid 103 in the active site is an essential catalytic residue involved in catalysis by hydrogen bonding to the dienolate intermediate.

High-resolution crystal structures of delta5-3-ketosteroid isomerase with and without a reaction intermediate analogue

Bacterial Delta5-3-ketosteroid isomerase (KSI) catalyzes a stereospecific isomerization of steroid substrates at an extremely fast rate, overcoming a large disparity of pKa values between a catalytic residue and its target. The crystal structures of KSI from Pseudomonas putida and of the enzyme in complex with equilenin, an analogue of the reaction intermediate, have been determined at 1.9 and 2.5 A resolution, respectively. The structures reveal that the side chains of Tyr14 and Asp99 (a newly identified catalytic residue) form hydrogen bonds directly with the oxyanion of the bound inhibitor in a completely apolar milieu of the active site. No water molecule is found at the active site, and the access of bulk solvent is blocked by a layer of apolar residues. Asp99 is surrounded by six apolar residues, and consequently, its pKa appears to be elevated as high as 9.5 to be consistent with early studies. No interaction was found between the bound inhibitor and the residue 101 (phenylalanine in Pseudomonas testosteroni and methionine in P. putida KSI) which was suggested to contribute significantly to the rate enhancement based on mutational analysis. This observation excludes the residue 101 as a potential catalytic residue and requires that the rate enhancement should be explained solely by Tyr14 and Asp99. Kinetic analyses of Y14F and D99L mutant enzymes demonstrate that Tyr14 contributes much more significantly to the rate enhancement than Asp99. Previous studies and the structural analysis strongly suggest that the low-barrier hydrogen bond of Tyr14 (>7.1 kcal/mol), along with a moderate strength hydrogen bond of Asp99 ( approximately 4 kcal/mol), accounts for the required energy of 11 kcal/mol for the transition-state stabilization.

High-resolution crystal structures of delta5-3-ketosteroid isomerase with and without a reaction intermediate analogue

Bacterial Delta5-3-ketosteroid isomerase (KSI) catalyzes a stereospecific isomerization of steroid substrates at an extremely fast rate, overcoming a large disparity of pKa values between a catalytic residue and its target. The crystal structures of KSI from Pseudomonas putida and of the enzyme in complex with equilenin, an analogue of the reaction intermediate, have been determined at 1.9 and 2.5 A resolution, respectively. The structures reveal that the side chains of Tyr14 and Asp99 (a newly identified catalytic residue) form hydrogen bonds directly with the oxyanion of the bound inhibitor in a completely apolar milieu of the active site. No water molecule is found at the active site, and the access of bulk solvent is blocked by a layer of apolar residues. Asp99 is surrounded by six apolar residues, and consequently, its pKa appears to be elevated as high as 9.5 to be consistent with early studies. No interaction was found between the bound inhibitor and the residue 101 (phenylalanine in Pseudomonas testosteroni and methionine in P. putida KSI) which was suggested to contribute significantly to the rate enhancement based on mutational analysis. This observation excludes the residue 101 as a potential catalytic residue and requires that the rate enhancement should be explained solely by Tyr14 and Asp99. Kinetic analyses of Y14F and D99L mutant enzymes demonstrate that Tyr14 contributes much more significantly to the rate enhancement than Asp99. Previous studies and the structural analysis strongly suggest that the low-barrier hydrogen bond of Tyr14 (>7.1 kcal/mol), along with a moderate strength hydrogen bond of Asp99 ( approximately 4 kcal/mol), accounts for the required energy of 11 kcal/mol for the transition-state stabilization.

The role of contrast enhanced computed tomography in the diagnosis of low density pulmonary nodules

Contrast enhanced CT manifestations of 141 pulmonary nodules having internal density less than 40 HU were evaluated to study the prevalence of causative disease and their differential points. Tuberculosis (n = 79) was most common, active in 96%. There were 22 cancers, 10 abscesses, 9 paragonimiases, 8 cysts, 7 metastases, 4 aspergillomas without air meniscus sign, and so on. 35% of the benign lesions were greater than 3 cm in diameter and 67% of benign lesions did not show a smooth outer margin. Lung cysts and aspergillomas showed relatively thin peripheral enhanced rim (PER), sharp transitional zone (TZ), a smooth inner border (IB), and homogeneous low densities (LD). Tuberculous nodules tended to be smaller in size with thin PER and most had smooth IB and homogeneous LD. Paragonimiasis, abscess, and cancer tended to present with thick PER and lobulated IB. Lung abscess and paragonimiasis both showed homogeneous LD and narrow TZ. However, in paragonimiasis, multiple locules were seen. Lung cancer showed wider TZ and heterogeneous LD. The size and outer margin of pulmonary nodules as a diagnostic criteria is less useful in LD pulmonary nodule. Therefore, CT can be more useful in differentiating the benign from the malignant lesions by observing a more specific and characteristic pattern of peripheral enhanced rim, transitional zone, inner border, and homogeneity of low density area.