Structure of ubiquitin-fold modifier 1-specific protease UfSP2

Ubiquitin-fold modifier 1 (Ufm1)-specific protease 2 (UfSP2) is a cysteine protease that is responsible for the release of Ufm1 from Ufm1-conjugated cellular proteins, as well as for the generation of mature Ufm1 from its precursor. The 2.6 Å resolution crystal structure of mouse UfSP2 reveals that it is composed of two domains. The C-terminal catalytic domain is similar to UfSP1 with Cys²⁹⁴, Asp⁴¹⁸, His⁴²⁰, Tyr²⁸², and a regulatory loop participating in catalysis. The novel N-terminal domain shows a unique structure and plays a role in the recognition of its cellular substrate C20orf116 and thus in the recruitment of UfSP2 to the endoplasmic reticulum, where C20orf116 predominantly localizes. Mutagenesis studies were carried out to provide the structural basis for understanding the loss of catalytic activity observed in a recently identified UfSP2 mutation that is associated with an autosomal dominant form of hip dysplasia.     

Salivary mRNA markers having the potential to detect oral squamous cell carcinoma segregated from oral leukoplakia with dysplasia

BackgroundIn the current study the presence of extracellular IL-1B, IL-8, OAZ and SAT mRNAs in the saliva was evaluated as a tool in the early detection of oral squamous cell carcinoma.Methods34 patients with primary oral squamous cell carcinoma stage T₁N₀M₀/T₂N₀M₀, 20 patients with oral leukoplakia and dysplasia (15 patients with mild dysplasia and 5 with severe dysplasia/in situ carcinoma) and 31 matched healthy-control subjects were included in the study. The presence of IL-1B, IL-8, OAZ and SAT mRNA was evaluated in extracellular RNA isolated from saliva samples using sequence-specific primers and real-time RT-PCR. ROC curve analysis was used to estimate the ability of the biomarkers to detect oral squamous cell carcinoma patients.ResultsThe data reveal that the combination of these four biomarkers provides a good predictive probability of up to 80% (AUC = 0.799, p = 0.002) for patients with oral squamous cell carcinoma but not patients suffering from oral leukoplakia with dysplasia. Moreover, the combination of only the two biomarkers (SAT and IL-8) also raises a high predictive ability of 75.5% (AUC = 0.755, p = 0.007) approximately equal to the four biomarkers suggesting the use of the two biomarkers only in the prediction model for oral squamous cell carcinoma patients limiting the economic and health cost in half.ConclusionSAT and IL-8 mRNAs are present in the saliva in high quality and quantity, with a good discriminatory ability for oral squamous cell carcinoma patients only but not for patients with oral leukoplakia and dysplasia an oral potentially malignant disorder.     

致心律失常性右室心肌病/ 发育不良1 例报告并文献复习

目的:探讨致心律失常性右室心肌病/发育不良的临床特点、病理特征诊断及治疗。方法:回顾性分析1例致心律失常性右室心肌病/发育不良的临床资料,并复习相关文献。结果:致心律失常性右室心肌病/发育不良常见临床表现有心悸、头晕、晕厥、气急胸闷,心电图可见延迟除极epsiton波。结论:致心律失常性右室心肌病/发育不良临床罕见,心脏超声及冠脉CT,心电图为主要确诊手段,治疗以限制运动与药物治疗为主。     

Proteomic analysis of liver tissue from HBx‐transgenic mice at early stages of hepatocarcinogenesis

The hepatitis B virus X‐protein (HBx), a multifunctional viral regulator, participates in the viral life cycle and in the development of hepatocellular carcinoma (HCC). We previously reported a high incidence of HCC in transgenic mice expressing HBx. In this study, proteomic analysis was performed to identify proteins that may be involved in hepatocarcinogenesis and/or that could be utilized as early detection biomarkers for HCC. Proteins from the liver tissue of HBx‐transgenic mice at early stages of carcinogenesis (dysplasia and hepatocellular adenoma) were separated by 2‐DE, and quantitative changes were analyzed. A total of 22 spots displaying significant quantitative changes were identified using LC‐MS/MS. In particular, several proteins involved in glucose and fatty acid metabolism, such as mitochondrial 3‐ketoacyl‐CoA thiolase, intestinal fatty acid‐binding protein 2 and cytoplasmic malate dehydrogenase, were differentially expressed, implying that significant metabolic alterations occurred during the early stages of hepatocarcinogenesis. The results of this proteomic analysis provide insights into the mechanism of HBx‐mediated hepatocarcinogenesis. Additionally, this study identifies possible therapeutic targets for HCC diagnosis and novel drug development for treatment of the disease.     

A novel RUNX2 mutation in exon 8, G462X,in a patient with Cleidocranial Dysplasia

To identify a novel mutation of Runx2 gene in Cleidocranial Dysplasia (CCD) patients and to characterize the functional consequences of this mutation. The subjects consisted of 12 Korean CCD patients. After oral epithelial cells were collected using a mouthwash technique, genomic DNA was extracted. Screening for Runx2 mutation was performed using direct sequencing of polymerase chain reaction (PCR) products for exons 1‐8. Restriction fragment length polymorphism (RFLP) analysis was performed to confirm the novel mutation. For functional studies, we performed luciferase assay for Runx2 transacting activity, cyclohexamide chase assay for Runx2 protein stability, real‐time PCR for mRNA level of Runx2 downstream bone marker genes, and alkaline phosphatase (ALP) staining assay in mesenchymal stem cells for osteoblast differentiation. Of the 12 patients, seven showed Runx2 mutations reported previously and four showed no mutation. A novel mutation, G462X in exon 8, which was located in the C‐terminus of proline/serine/threonine‐rich (PST) domain, was found in one patient. In the luciferase assay, Runx2 transacting activity was decreased in Runx2‐G462X transfected cells. In the cyclohexamide chase assay, Runx2‐G462X mutation reduced the stability of Runx2 protein. Expression of the bone marker genes (osteocalcin, ALP, Type I collagen αI, matrix metalloproteinase‐13, bone sialoprotein, and osteopontin) decreased in G462X‐transfected cells. In the ALP staining assay, osteoblast differentiation was reduced in Runx2‐G462X overexpressed cell. The G462X mutation might reduce the Runx2 transacting activity, lower the protein stability, downgrade the expression of bone marker genes, and eventually diminish osteoblast differentiation in CCD patients.     

CDX2在胃癌及癌前病变组织中的表达及其临床意义

目的研究CDX2在胃癌及癌前病变组织中的表达及其与临床病理因素之间的关系。方法采用免疫组织化学S-P法检测CDX2在胃癌及癌前病变组织中的表达,采用阿新兰/过碘酸雪夫氏染色(AB/PAS)和高铁二铵/阿新兰(HID/AB)染色对胃黏膜肠化生进行分型。结果 (1)CDX2在正常胃黏膜组织、慢性浅表性胃炎中不表达,CDX2在肠化、异型增生及胃癌中的阳性率(81.7%、50%、48.2%)均明显高于正常胃黏膜组织(P0.05),在肠化组织中的表达明显高于异型增生和胃癌(P0.05),在异型增生和胃癌中的阳性率差异无显著性(P0.05)。CDX2的表达与肠化的分型和异型增生的分级之间均无关系。(2)CDX2在肠型胃癌中的阳性率(67.4%)明显高于弥漫型和混合型胃癌(25.7%、42.9%);CDX2的表达与胃癌分化程度呈正相关,而与淋巴结转移和临床分期呈负相关,差异均有统计学意义。CDX2阳性表达组的五年生存率明显高于阴性表达组(P=0.038);多种变量对胃癌患者术后生存时间影响的分析显示,CDX2的表达和淋巴结转移是影响胃癌预后的独立因素(P0.05)。结论 CDX2可能在胃粘膜肠化生的发生及胃癌的发生发展中起重要作用,可作为胃癌诊断、判断胃癌的恶性程度及患者预后的有用指标。     

Chronic lung injury in the neonatal rat: Up-regulation of TGFβ1 and nitration of IGF-R1 by peroxynitrite as likely contributors to impaired alveologenesis

Postnatal alveolarization is regulated by a number of growth factors, including insulin-like growth factor-I (IGF-I) acting through the insulin-like growth factor receptor-1 (IGF-R1). Exposure of the neonatal rat lung to 60% O₂ for 14 days results in impairments of lung cell proliferation, secondary crest formation, and alveologenesis. This lung injury is mediated by peroxynitrite and is prevented by treatment with a peroxynitrite decomposition catalyst. We hypothesized that one of the mechanisms by which peroxynitrite induces lung injury in 60% O₂ is through nitration and inactivation of critical growth factors or their receptors. Increased nitration of both IGF-I and IGF-R1 was evident in 60% O₂-exposed lungs, which was reversible by concurrent treatment with a peroxynitrite decomposition catalyst. Increased nitration of the IGF-R1 was associated with its reduced activation, as assessed by IGF-R1 phosphotyrosine content. IGF-I displacement binding plots were conducted in vitro using rat fetal lung distal epithelial cells which respond to IGF-I by an increase in DNA synthesis. When IGF-I was nitrated to a degree similar to that observed in vivo there was minimal, if any, effect on IGF-I displacement binding. In contrast, nitrating cell IGF-R1 to a similar degree to that observed in vivo completely prevented specific binding of IGF-I to the IGF-R1, and attenuated an IGF-I-mediated increase in DNA synthesis. Additionally, we hypothesized that peroxynitrite also impairs alveologenesis by being an upstream regulator of the growth inhibitor, TGFβ1. That 60% O₂-induced impairment of alveologenesis was mediated in part by TGFβ1 was confirmed by demonstrating an improvement in secondary crest formation when 60% O₂-exposed pups received concurrent treatment with the TGFß1 activin receptor-like kinase, SB 431542. That the increased TGFβ1 content in lungs of pups exposed to 60% O₂ was regulated by peroxynitrite was confirmed by its attenuation by concurrent treatment with a peroxynitrite decomposition catalyst. We conclude that peroxynitrite contributes to the impaired alveologenesis observed following the exposure of neonatal rats to 60% O₂ both by preventing binding of IGF-I to the IGF-R1, secondary to nitration of the IGF-R1, and by causing an up-regulation of the growth inhibitor, TGFβ1.