LncRNA ZNNT1 induces p53 degradation by interfering with the interaction between p53 and the SART3-USP15 complex.

Mammalian genomes encode large number of long noncoding RNAs (lncRNAs) that play key roles in various biological processes, including proliferation, differentiation, and stem cell pluripotency. Recent studies have addressed that some lncRNAs are dysregulated in human cancers and may play crucial roles in tumor development and progression. Here, we show that the lncRNA ZNNT1 is required for the proliferation and tumorigenicity of colon cancer cells with wild-type p53. ZNNT1 knockdown leads to decreased ubiquitination and stabilization of p53 protein. Moreover, we demonstrate that ZNNT1 needs to interact with SART3 to destabilize p53 and to promote the proliferation and tumorigenicity of colon cancer cells. We further show that SART3 is associated with the ubiquitin-specific peptidase USP15 and that ZNNT1 may induce p53 destabilization by inhibiting this interaction. These results suggest that ZNNT1 interferes with the SART3-USP15 complex-mediated stabilization of p53 protein and thereby plays important roles in the proliferation and tumorigenicity of colon cancer cells. Our findings suggest that ZNNT1 may be a promising molecular target for the therapy of colon cancer.

Unusual nucleosome formation and transcriptome influence by the histone H3mm18 variant.

Histone H3mm18 is a non-allelic H3 variant expressed in skeletal muscle and brain in mice. However, its function has remained enigmatic. We found that H3mm18 is incorporated into chromatin in cells with low efficiency, as compared to H3.3. We determined the structures of the nucleosome core particle (NCP) containing H3mm18 by cryo-electron microscopy, which revealed that the entry/exit DNA regions are drastically disordered in the H3mm18 NCP. Consistently, the H3mm18 NCP is substantially unstable in vitro. The forced expression of H3mm18 in mouse myoblast C2C12 cells markedly suppressed muscle differentiation. A transcriptome analysis revealed that the forced expression of H3mm18 affected the expression of multiple genes, and suppressed a group of genes involved in muscle development. These results suggest a novel gene expression regulation system in which the chromatin landscape is altered by the formation of unusual nucleosomes with a histone variant, H3mm18, and provide important insight into understanding transcription regulation by chromatin.

UHRF1-KAT7-mediated regulation of TUSC3 expression via histone methylation/acetylation is critical for the proliferation of colon cancer cells.

The epigenetic factor UHRF1 regulates transcription by modulating DNA methylation and histone modification, and plays critical roles in proliferation, development, and tumorigenesis. Here, we show that Wnt/c-Myc signaling upregulates UHRF1, which in turn downregulates TUSC3, a candidate tumor suppressor gene that is frequently deleted or downregulated in several cancers. We also show that UHRF1-mediated downregulation of TUSC3 is required for the proliferation of colon cancer cells. Furthermore, we demonstrate that UHRF1 suppresses TUSC3 expression by interacting with methylated H3K14 and thereby suppressing the acetylation of H3K14 by the histone acetyltransferase KAT7. Our study provides evidence for the significance of UHRF1-KAT7-mediated regulation of histone methylation/acetylation in the proliferation of tumor cells and in a diverse set of biological processes controlled by Wnt/c-Myc signaling.

The Autism-Related Protein PX-RICS Mediates GABAergic Synaptic Plasticity in Hippocampal Neurons and Emotional Learning in Mice.

GABAergic dysfunction underlies many neurodevelopmental and psychiatric disorders. GABAergic synapses exhibit several forms of plasticity at both pre- and postsynaptic levels. NMDA receptor (NMDAR)-dependent inhibitory long-term potentiation (iLTP) at GABAergic postsynapses requires an increase in surface GABAARs through promoted exocytosis; however, the regulatory mechanisms and the neuropathological significance remain unclear. Here we report that the autism-related protein PX-RICS is involved in GABAAR transport driven during NMDAR-dependent GABAergic iLTP. Chemically induced iLTP elicited a rapid increase in surface GABAARs in wild-type mouse hippocampal neurons, but not in PX-RICS/RICS-deficient neurons. This increase in surface GABAARs required the PX-RICS/GABARAP/14-3-3 complex, as revealed by gene knockdown and rescue studies. iLTP induced CaMKII-dependent phosphorylation of PX-RICS to promote PX-RICS-14-3-3 assembly. Notably, PX-RICS/RICS-deficient mice showed impaired amygdala-dependent fear learning, which was ameliorated by potentiating GABAergic activity with clonazepam. Our results suggest that PX-RICS-mediated GABAAR trafficking is a key target for GABAergic plasticity and its dysfunction leads to atypical emotional processing underlying autism.

ASBEL-TCF3 complex is required for the tumorigenicity of colorectal cancer cells.

Wnt/ß-catenin signaling plays a key role in the tumorigenicity of colon cancer. Furthermore, it has been reported that lncRNAs are dysregulated in several steps of cancer development. Here we show that ß-catenin directly activates the transcription of the long noncoding RNA (lncRNA) ASBEL [antisense ncRNA in the ANA (Abundant in neuroepithelium area)/BTG3 (B-cell translocation gene 3) locus] and transcription factor 3 (TCF3), both of which are required for the survival and tumorigenicity of colorectal cancer cells. ASBEL interacts with and recruits TCF3 to the activating transcription factor 3 (ATF3) locus, where it represses the expression of ATF3. Furthermore, we demonstrate that ASBEL-TCF3-mediated down-regulation of ATF3 expression is required for the proliferation and tumorigenicity of colon tumor cells. ATF3, in turn, represses the expression of ASBEL Our results reveal a pathway involving an lncRNA and two transcription factors that plays a key role in Wnt/ß-catenin-mediated tumorigenesis. These results may provide insights into the variety of biological and pathological processes regulated by Wnt/ß-catenin signaling.

PX-RICS-deficient mice mimic autism spectrum disorder in Jacobsen syndrome through impaired GABAA receptor trafficking.

Jacobsen syndrome (JBS) is a rare congenital disorder caused by a terminal deletion of the long arm of chromosome 11. A subset of patients exhibit social behavioural problems that meet the diagnostic criteria for autism spectrum disorder (ASD); however, the underlying molecular pathogenesis remains poorly understood. PX-RICS is located in the chromosomal region commonly deleted in JBS patients with autistic-like behaviour. Here we report that PX-RICS-deficient mice exhibit ASD-like social behaviours and ASD-related comorbidities. PX-RICS-deficient neurons show reduced surface γ-aminobutyric acid type A receptor (GABAAR) levels and impaired GABAAR-mediated synaptic transmission. PX-RICS, GABARAP and 14-3-3ζ/θ form an adaptor complex that interconnects GABAAR and dynein/dynactin, thereby facilitating GABAAR surface expression. ASD-like behavioural abnormalities in PX-RICS-deficient mice are ameliorated by enhancing inhibitory synaptic transmission with a GABAAR agonist. Our findings demonstrate a critical role of PX-RICS in cognition and suggest a causal link between PX-RICS deletion and ASD-like behaviour in JBS patients.

Long noncoding RNA UPAT promotes colon tumorigenesis by inhibiting degradation of UHRF1.

Many long noncoding RNAs (lncRNAs) are reported to be dysregulated in human cancers and play critical roles in tumor development and progression. Furthermore, it has been reported that many lncRNAs regulate gene expression by recruiting chromatin remodeling complexes to specific genomic loci or by controlling transcriptional or posttranscriptional processes. Here we show that an lncRNA termed UPAT [ubiquitin-like plant homeodomain (PHD) and really interesting new gene (RING) finger domain-containing protein 1 (UHRF1) Protein Associated Transcript] is required for the survival and tumorigenicity of colorectal cancer cells. UPAT interacts with and stabilizes the epigenetic factor UHRF1 by interfering with its ß-transducin repeat-containing protein (TrCP)-mediated ubiquitination. Furthermore, we demonstrate that UHRF1 up-regulates Stearoyl-CoA desaturase 1 and Sprouty 4, which are required for the survival of colon tumor cells. Our study provides evidence for an lncRNA that regulates protein ubiquitination and degradation and thereby plays a critical role in the survival and tumorigenicity of tumor cells. Our results suggest that UPAT and UHRF1 may be promising molecular targets for the therapy of colon cancer.

Heterogeneous nuclear ribonucleoprotein K upregulates the kinetochore complex component NUF2 and promotes the tumorigenicity of colon cancer cells.

Heterogeneous nuclear ribonucleoprotein K (hnRNP K) is a multi-functional protein involved in transcription, mRNA splicing, mRNA stabilization and translation. Although hnRNP K has been suggested to play a role in the development of many cancers, its molecular function in colorectal cancer has remained elusive. Here we show that hnRNP K plays an important role in the mitotic process in HCT116 colon cancer cells. Furthermore, we demonstrate that hnRNP K directly transactivates the NUF2 gene, the product of which is a component of the NDC80 kinetochore complex and which is known to be critical for a stable spindle microtubule-kinetochore attachment. In addition, knockdown of both hnRNP K and NUF2 caused failure in metaphase chromosome alignment and drastic decrease in the growth of colon cancer cells. These results suggest that the hnRNP K-NUF2 axis is important for the mitotic process and proliferation of colon cancer cells and that this axis could be a target for the therapy of colon cancer.

Long-term survival of patients with pulmonary arterial hypertension recovering to World Health Organization functional class I or II: a historical comparison between intravenous epoprostenol and oral agents.

BACKGROUND: Intravenous epoprostenol is the only drug proved in a randomized study to reduce mortality in patients with idiopathic pulmonary arterial hypertension (PAH). However, administration of this drug has procedural difficulties and a risk of sepsis. Oral drugs provide simple treatment, but their benefit for survival has not been proven. A recovery of patients with PAH to World Health Organization functional class (WHO-FC) I or II may predict favorable survival. METHODS: Survival analyses were performed on a historical cohort of 41 patients with PAH. The patients were 43 ± 22 years old, 23 had idiopathic or heritable PAH, and 18 had connective tissue disease-associated PAH. The baseline was defined as the initial visit to a medical facility. RESULTS: The median duration of follow-up was 1276 days (108 to 5389 days) and 21 patients died during this period. The estimated survival times for patients who received intravenous epoprostenol and did and did not recover to WHO-FC I or II were 4371 ± 577 days and 1172 ± 404 days, respectively. These times for patients who were not treated with intravenous epoprostenol and did and did not recover to WHO-FC I or II were 4717 ± 554 days and 925 ± 230 days, respectively. A Cox proportional hazard analysis gave a hazard ratio for death after recovery to WHO-FC I or II of 0.07 (P < 0.001). In contrast, use of intravenous epoprostenol was not a significant factor affecting survival (P = 0.96). CONCLUSIONS: Patients with PAH who achieve recovery to WHO-FC I or II without use of intravenous epoprostenol have similar survival to those who reach the same WHO-FC with use of intravenous epoprostenol. Benign survival of patients with PAH who have recovered to WHO-FC I or II may extend for several years after onset of the disease.

[Cardiovascular performance assessed with exercise testing].

Since the first exercise electrocardiography was recorded in 1908, it has been in widespread clinical use for more than 100 years. Exercise testing can be performed easily and noninvasively and is relatively inexpensive. This testing is generally safe but myocardial infarction and death occur rarely. The Japanese Circulation Society describes the wide applications of exercise testing in the guidelines. The guideline for ischemic heart disease prioritizes exercise testing for the diagnosis of stable angina pectoris. Although the sensitivity and specificity are not as high as other noninvasive testing (i.e., stress single-photon emission computed tomography, computed tomography and MRI), exercise testing can also assess the severity and prognosis of the disease. Cardiac rehabilitation is a useful tool to improve the prognosis of patients with myocardial infarction. Exercise therapy is a main component of cardiac rehabilitation, and exercise testing is indispensable for prescribing exercise therapy. Exercise capacity is an important prognostic factor in patients with heart failure. The guideline for the diagnosis of chronic heart failure recommends cardiopulmonary exercise testing to evaluate exercise capacity.

ASBEL, an ANA/BTG3 antisense transcript required for tumorigenicity of ovarian carcinoma.

Mammalian genomes encode numerous antisense non-coding RNAs, which are assumed to be involved in the regulation of the sense gene expression. However, the mechanisms of their action and involvement in the development of diseases have not been well elucidated. The ANA/BTG3 protein is an antiproliferative protein whose expression is downregulated in prostate and lung cancers. Here we show that an antisense transcript of the ANA/BTG3 gene, termed ASBEL, negatively regulates the levels of ANA/BTG3 protein, but not of ANA/BTG3 mRNA and is required for proliferation and tumorigenicity of ovarian clear cell carcinoma. We further show that knockdown of ANA/BTG3 rescues growth inhibition caused by ASBEL knockdown. Moreover, we demonstrate that ASBEL forms duplexes with ANA/BTG3 mRNA in the nucleus and suppresses its cytoplasmic transportation. Our findings illustrate a novel function for an antisense transcript that critically promotes tumorigenesis by suppressing translation of the sense gene by inhibiting its cytoplasmic transportation.

Pulmonary venous occlusion and death in pulmonary arterial hypertension: survival analyses using radiographic surrogates.

BACKGROUND: Recent studies find that a considerable number of patients with pulmonary arterial hypertension (PAH) develop fibrous obstruction of the pulmonary veins. Such obstruction more commonly accompanies connective tissue disorder (CTD)-associated PAH than idiopathic PAH. However, few researchers have gauged the risk of death involving obstruction of the pulmonary veins. METHODS: Thirty-seven patients with PAH were enrolled (18 patients, idiopathic PAH; 19 patients, CTD-associated PAH). The patients were 49 ± 18 years and had a World Health Organization functional class of 3.2 ± 0.6. Thickening of the interlobular septa, centrilobular ground-glass attenuation, and mediastinal adenopathy were surrogates for obstruction of the pulmonary veins, and were detected by a 16-row multidetector computed tomography scanner. RESULTS: The follow-up period was 714 ± 552 days. Fifteen deaths occurred. Thickening of the interlobular septa, centrilobular ground-glass attenuation, and mediastinal adenopathy were found in 37.8%, 24.3%, and 16.2% of patients, respectively. Cox proportional hazard analysis revealed an increased risk of death with each radiographic surrogate (mediastinal adenopathy: p < 0.0001, hazard ratio = 13.9; thickening of interlobular septa: p < 0.001, hazard ratio = 12.0; ground-glass attenuation: p = 0.02, hazard ratio = 3.7). The statistical significance of these relationships was independent of the cause of PAH and plasma concentration of brain natriuretic peptide. CONCLUSIONS: The results of this study imply that obstruction of the pulmonary veins is associated with an increased risk of death in patients with PAH.

A genetic screen for mutations affecting gonad formation in Drosophila reveals a role for the slit/robo pathway.

Organogenesis is a complex process requiring multiple cell types to associate with one another through correct cell contacts and in the correct location to achieve proper organ morphology and function. To better understand the mechanisms underlying gonad formation, we performed a mutagenesis screen in Drosophila and identified twenty-four genes required for gonadogenesis. These genes affect all different aspects of gonad formation and provide a framework for understanding the molecular mechanisms that control these processes. We find that gonad formation is regulated by multiple, independent pathways; some of these regulate the key cell adhesion molecule DE-cadherin, while others act through distinct mechanisms. In addition, we discover that the Slit/Roundabout pathway, best known for its role in regulating axonal guidance, is essential for proper gonad formation. Our findings shed light on the complexities of gonadogenesis and the genetic regulation required for proper organ formation.

Bilirubin as a prognostic marker in patients with pulmonary arterial hypertension.

BACKGROUND: Liver dysfunction reflects the status of heart failure, with congestion and low perfusion of the liver serving as causative mechanisms. Previous studies demonstrated relationship between the results of liver function test and the prognosis in patients with heart failure. However, few studies have examined this relationship in patients with pulmonary arterial hypertension (PAH). METHODS: The subjects were 37 patients with PAH (8 men and 29 women; 18 with idiopathic PAH and 19 with connective tissue disease-associated PAH). A blood test was performed after a 3-month period free from hospitalization and without changes in functional class, treatment, heart sounds, body weight, or heart rate. RESULTS: In a mean follow-up period of 635 +/- 510 days, 12 patients died due to heart failure, 2 died due to pulmonary hemorrhage, and 23 patients survived. Cox proportional hazard analyses identified functional class (p < 0.001), plasma concentration of brain natriuretic peptide (BNP) (p = 0.001), and hyperbilirubinemia (serum total bilirubin > 1.2 mg/dL; p < 0.001; hazard ratio = 13.31) as predictors of mortality. Patients with hyperbilirubinemia had a worse functional class (P = 0.003), a higher right atrial pressure (p < 0.001), a higher plasma concentration of BNP (p = 0.004), and a larger Doppler right ventricular index of the right ventricle (p = 0.041). CONCLUSION: Elevated serum bilirubin is a risk factor for death in patients with PAH.

Within-person variation of the plasma concentration of B-type natriuretic peptide: safety range in stable patients with heart failure.

BACKGROUND: The plasma concentration of B-type natriuretic peptide (BNP) in outpatients is hard to interpret because of the lack of knowledge of the natural within-person variation of BNP. In this study, we estimated the safety range of within-person variation in the plasma concentration of BNP in outpatients with stable heart failure. METHODS: In a prospective historical cohort study, 6 consecutive measurements of the plasma concentration of BNP were made at 4-week intervals in 131 consecutive patients with strictly stable heart failure. The reference change values at the 95% CI and the 95% limits of agreement of the peptide concentration were calculated with a log-normal approach, and the results were back-transformed to a normal scale. RESULTS: The within-person distribution of BNP was right-skewed, and a Gaussian distribution was achieved by log transformation. In all of 15 combinations of paired measurements randomly selected from 6 measurements, the correlations were significant (P < .001) with correlation coefficients ranging from 0.615 to 0.835. The up and down reference change values at the 95% confidence level for all measurements were 240.4% and -70.6% of the geometric means, respectively, and the median values of the upper and lower 95% limits of agreements were 219.7% and -71.8% of the geometric mean, respectively. CONCLUSION: The plasma concentration of BNP may triple or fall by one third without a change in the status of heart failure. In monitoring of patients with heart failure, BNP should be interpreted in the context of the skewed within-person distribution.

The relationship between variables of 123-I-metaiodobenzylguanidine cardiac imaging and clinical status of the patients with diastolic heart failure.

BACKGROUND: The status of cardiac sympathetic nerve activity in patients with diastolic heart failure has not been fully understood. 123-I-metaiodobenzylguanidine cardiac images are valuable for evaluating cardiac sympathetic nerve activity. METHODS: We obtained 123-I-metaiodobenzylguanidine cardiac images from 34 consecutive patients with moderate heart failure and an ejection fraction of > or = 45%. RESULTS: The decay-corrected washout rate of 123-I-metaiodobenzylguanidine correlated with each plasma concentration of brain natriuretic peptide (standardized correlation coefficient=0.305, p<0.05), New York Heart Association functional class (standardized correlation coefficient=0.364, p<0.02), and exercise capacity (standardized correlation coefficient=-0.388, p<0.04). A multiple regression analysis revealed that the washout rate independently predicted plasma concentration of brain natriuretic peptide (standardized regression coefficient=0.367, p<0.02). In a univariate regression, the washout rate did not significantly correlate with the presence of ischemic heart disease (p=0.254); in a multivariate regression, the presence of ischemic heart disease did not predict the washout rate. For the 14 patients with sinus rhythm, there was a marginal negative correlation between the E/A velocity ratio of the transmitral flow and washout rate (standardized correlation coefficient=-0.518, p<0.07). CONCLUSIONS: In diastolic heart failure, cardiac sympathetic nerve activity increases proportionally to severity of the disease.