A case of Rubinstein-Taybi syndrome caused by a variant of EP300 gene / 中华医学遗传学杂志

OBJECTIVE@#To explore the clinical characteristics and genetic etiology of a child with Rubinstein-Taybi syndrome (RSTS).@*METHODS@#A child who was admitted to the Children's Hospital of Soochow University on October 3, 2021 was selected as the study subject. Clinical data of the child was collected. Peripheral blood samples of the child and his parents were collected. The child was subjected to whole exome sequencing (WES), and candidate variant was verified by Sanger sequencing of his family members and bioinformatic analysis.@*RESULTS@#The patient, a 9-year-and-４-month-old boy, had manifested unique facies, microcephaly, broad toes, growth retardation, and intellectual impairment. WES revealed that he has harbored a heterozygous c.3604G>T (p.E1202*) variant in exon 20 of the EP300 gene. Sanger sequencing confirmed that neither of his parents has carried the same variant. The variant was not found in the Shenzhou Genome data Cloud, ExAC, 1000 Genomes and gnomAD databases．Analysis with SIFT, PolyPhen-2 and CADD online software has predicted the variant to be harmful. Based on the guidelines formulated by the American College of Medical Genetics and Genomics, the variant was rated as pathogenic (PVS1＋PS2＋PM2_Supporting) .@*CONCLUSION@#The heterozygous c.3604G>T variant of the EP300 gene probably underlay the RSTS type 2 in this child. Above finding has also expanded the variation spectrum of the EP300 gene.

AMP-activated protein kinase activation regulates adhesion of monocytes to vascular endothelial cells and the underlying mechanism / 生理学报

The present study was aimed to explore the effect of AMP-activated protein kinase (AMPK) on monocyte adhesion to vascular endothelial cells and underlying molecular mechanism. Tumor necrosis factor α (TNFα)-activated human aortic endothelial cells (HAECs) were treated with different concentrations of AMPK agonist 5-Aminoimidazole-4-carboxamide-1-β-D-ribonucleotide (AICAR) or AMPK inhibitor compound C. And other HAECs were overexpressed with constitutive active or dominant negative AMPK protein and then treated with TNFα. The rates of monocytes adhering to endothelial cells were detected by fluorescent staining. Intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) mRNA levels and protein secretions were detected by quantitative PCR and ELISA, respectively. Acetylation of NF-κB p65 at lysine 221 site was assessed by Western blot. NF-κB p65 DNA binding activity was analyzed by an ELISA-based method. By using small interfering RNA based strategy, p300 expression in HAECs was down-regulated and then cells were incubated with TNFα. NF-κB p65 DNA binding activity, ICAM-1 and VCAM-1 expressions and adhesion rates were detected, respectively. The activity of p300 was also detected by ELISA. The results showed that AICAR treatment significantly reduced monocyte-endothelial adhesion rate, as well as ICAM-1 and VCAM-1 mRNA levels and protein secretions, in TNFα-activated HAECs. Moreover, transfection of constitutive active AMPKα but not dominant negative AMPKα strongly diminished TNFα-induced upregulation of ICAM-1 and VCAM-1 mRNA expressions and secretions, as well as monocyte-endothelial adhesion. Furthermore, AMPK activation decreased TNFα-mediated acetylation of NF-κB p65 at Lys221 site and reduced NF-κB p65 DNA binding activity. Silencing p300 by siRNA significantly abolished the effect of TNFα- induced adhesion molecules expression and monocyte-endothelial adhesion. Blocking AMPK activation by compound C almost completely reversed the effect of AICAR exerted on HAECs. These results suggest AMPK activation suppresses monocyte-endothelial adhesion, and the underlying mechanism is relevant to the inhibition of p300 activity and NF-κB p65 transcriptional activity.

Development of a novel screening assay for inhibitors targeting HIF-1alpha and P300 interaction / 药学学报

Hypoxia is a general characteristic of most solid malignancies and intimately related to cancer progression. Homeostatic response to hypoxia is primarily mediated by hypoxia inducible factor-1alpha (HIF-1alpha) that elicits transcriptional activity through recruitment P300 coactivator. Targeting the interaction of HIF- alpha and P300 would thus constitute a novel approach for cancer treatment by suppressing tumor angiogenesis and metastasis. Here, a screening assay was developed for inhibitors targeting the interaction between HIF-1alpha and P300. The nucleotide sequence of human HIF-1alpha and P300 were cloned into pBIND and pACT vectors, named pBIND-HIF1alpha and pACT-P300. The interaction of HIF-1alpha and P300 was identified in HEK293 cell using mammalian two-hybrid system. And compound chetomin decreased their interaction in this mammalian two-hybrid system. We further verified HIF-1 inhibition effect of chetomin in U251-HRE cells. Therefore, we established a screening assay combined HIF-1alpha and P300 mammalian two-hybrid system and U251-HRE reporter assay for HIF-1 selective inhibitors.

Histone acetylation and expression of acetylation-related enzymes in children with tetralogy of Fallot / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the expression of histone acetyltransferases (HATs) and histone deacetylases (HDACs) in children with tetralogy of Fallot (TOF), and to investigate the role of histone acetylation and acetylation-related enzymes in the pathogenesis of TOF.</p><p><b>METHODS</b>Myocardial tissue samples in the TOF group were obtained from 46 children with TOF who underwent radical operation, and myocardial tissue samples in the control group were obtained from 16 children who suffered accidental deaths and had no cardiac anomalies as shown by autopsy. The acetylation of H3K9, H3K18 and H3K27 was evaluated by immunohistochemistry. The mRNA expression of HATs and HDACs in the myocardium was measured by real-time PCR. The correlation between mRNA expression of HATs and HDACs and histone acetylation was analyzed.</p><p><b>RESULTS</b>Compared with the control group, the TOF group showed significantly increased acetylation of H3K9 (P=0.0165) and significantly decreased acetylation of H3K18 (P=0.0048) and H3K27 (P=0.0084). As to 4 HATs and 6 HDACs, the mRNA expression of EP300 and CBP was significantly higher in the TOF group than in the control group (P=0.025; P=0.017), and there was no significant difference in the mRNA expression of other HATs and HDACs between the two groups. The correlation analysis revealed a positive correlation between H3K9 acetylation and mRNA expression of EP300 (r=0.71, P<0.01) and CBP (r=0.72, P<0.01).</p><p><b>CONCLUSIONS</b>Upregulated mRNA expression of EP300 and CBP may be associated with increased H3K9 acetylation, suggesting that EP300 and CBP might affect cardiac development by regulating H3K9 acetylation.</p>

Regulatory effect of curcumin on p300 and HDAC1 in B-NHL cells / 中国实验血液学杂志

The purpose of this study was to investigate the effect of curcumin on proliferation of B-NHL Raji cell line and explore the relationship between this effect and regulatory expression of p300 and HDAC1 transcription. The in vitro cultured Raji cells were treated with curcumin at various concentrations (6.25-50 micromol/L) and at different time points (0, 6, 12, 24 and 48 hours), the inhibitory ratio of cell growth was measured by MTT assay, the cell apoptosis rate was detected by flow cytometry with Annexin V-FITC/PI double staining, the changes of p300 and HDAC1 mRNA expression and protein level in Raji cells were determined by RT-PCR and Western blot. The results showed that the curcumin could inhibit Raji cell proliferation in significant time-and concentration-dependent manners, IC50 at 24 hours was 25 micromol/L; the curcumin could induce apoptosis of Raji cells in concentration-dependent manner, apoptosis rate was 14.38%-61.18%. The curcumin significantly inhibited activity and expression of p300 and HDAC1. At IC50 concentration, expression of p300 and HDAC1 mRNA and protein level decreased with time-dependent manner, difference between tested and control groups was significant (P < 0.05). It is concluded that the curcumin can inhibit proliferation of B-NHL Raji cells and promote apoptosis of those cells. Curcumin can inhibit the activity and expression of the transcriptional co-activator p300 and HDAC1, which may be involved in its pharmacological mechanisms on B lymphoma cells.