ShcC proteins: Brain aging and beyond

To date, most studies of Shc family of signaling adaptor proteins have been focused on the near-ubiquitously expressed ShcA, indicating its relevance to age-related diseases and longevity. Although the role of the neuronal ShcC protein is much less investigated, accumulated evidence suggests its importance for neuroprotection against such aging-associated conditions as brain ischemia and oxidative stress. Here, we summarize more than decade of studies on the ShcC expression and function in normal brain, age-related brain pathologies and immune disorders with a focus on the interactions of ShcC with signaling proteins/pathways, and the possible implications of these interactions for changes associated with aging.     

氧化应激促发颅内动脉瘤的研究进展

氧化应激与炎性反应是颅内动脉瘤(CA)形成和破裂的核心因素。作用机制为:1)直接损伤脑动脉内膜;2)使血管平滑肌细胞(VSMC)由可收缩型向炎性反应型转化并凋亡;3)募集炎性细胞、分泌炎性因子,侵袭管壁;4)激活基质金属蛋白酶(MMP),重构和解体血管壁;5)介导脂质过氧化,引起动脉粥样硬化和高血压。初步研究显示阻断氧化应激可预防CA发展,但详细机制尚需进一步探究。     

缺氧应激反应中活性氧与缺氧诱导因子-1的相互作用

在缺氧条件下,线粒体会产生大量的活性氧（ reactive oxygen species, ROS）,随即大量的活性氧将会诱导机体产生缺氧应激反应。缺氧诱导因子1（hypoxia inducible factor 1, HIF?1）是缺氧应激反应中的中枢调控因子。有研究表明, ROS主要通过抑制脯氨酸羟化酶家族（ prolyl hydroxylases, PHDs）的活性来抑制HIF?1α的泛素化降解,从而稳定HIF?1。而HIF?1蛋白水平的升高有助于机体应对缺氧微环境。最近研究还发现, REDD?1可以通过ROS对HIF?1产生负调控作用,从而抑制肿瘤的形成;秀丽线虫呼吸突变体的产生会导致ROS水平增加,从而增强HIF?1的活性,最终延长的线虫寿命;以及ROS、 HIF?1促进自噬的产生。因此,了解缺氧条件下ROS与HIF?1之间的相互作用关系,对于今后肿瘤、衰老和自噬的研究具有重要意义。     

Location,identity, amount and serial entry of chloroplast DNA sequences in crucifer mitochondrial DNAs

Southern blot hybridization techniques were used to examine the chloroplast DNA (cpDNA) sequences present in the mitochondrial DNAs (mtDNAs) of two Brassica species (B. campestris and B. hirta), two closely related species belonging to the same tribe as Brassica (Raphanus sativa, Crambe abyssinica), and two more distantly related species of crucifers (Arabidopsis thaliana, Capsella bursa-pastoris). The two Brassica species and R. sativa contain roughly equal amounts (12–14 kb) of cpDNA sequences integrated within their 208–242 kb mtDNAs. Furthermore, the 11 identified regions of transferred DNA, which include the 5 end of the chloroplast psaA gene and the central segment of rpoB, have the same mtDNA locations in these three species. Crambe abyssinica mtDNA has the same complement of cpDNA sequences, plus an additional major region of cpDNA sequence similarity which includes the 16S rRNA gene. Therefore, except for the more recently arrived 16S rRNA gene, all of these cpDNA sequences appear to have entered the mitochondrial genome in the common ancestor of these three genera. The mitochondrial genomes of A. thaliana and Capsella bursa-pastoris contain significantly less cpDNA (5–7 kb) than the four other mtDNAs. However, certain cpDNA sequences, including the central portion of the rbcL gene and the 3 end of the psaA gene, are shared by all six crucifer mtDNAs and appear to have been transferred in a common ancestor of the crucifer family over 30 million years ago. 1n conclusion, DNA has been transferred sequentially from the chloroplast to the mitochondrion during crucifer evolution and these cpDNA sequences can persist in the mitochondrial genome over long periods of evolutionary time.     

Misdiagnosis of attention deficit hyperactivity disorder: ‘Normal behaviour’ and relative maturity

Attention deficit hyperactivity disorder (ADHD) is one of the most frequently diagnosed disorders in children, yet it remains poorly understood. Substantial controversy exists regarding correct diagnosis of ADHD, and areas of subjectivity in diagnosis have been identified. Concerns for appropriate diagnosis are critical in terms of children’s educational outcomes, as well as health concerns associated with the use and potential overuse of stimulant medications. There exists a relative-age effect in which children who are relatively younger than their peers and born closest to the school start age cut-off are more frequently diagnosed and treated for ADHD. Additionally, substantial variation exists in ADHD diagnosis between boys and girls, with boys often presenting with more stereotypical symptoms. Both the relative-age effect and variation in sex diagnosis, as well as the challenges of early preschool diagnosis, emphasize the importance of considering relative maturity in ADHD diagnosis of children. Implications and knowledge translation strategies for practitioners, parents and the education system are presented.     

eNOS和NADPH氧化酶在慢性缺氧条件下小鼠肺组织中表达关系的研究

目的 探讨eNOS 和NADPH 氧化酶在慢性缺氧条件下小鼠肺组织中表达的关系。方法 将野生型及eNOS 基因敲除的C57BL/6 雄性小鼠各30 只随机分为常氧组、低氧7d组、低氧21d组、治疗7d组和治疗21d组,每种每组小鼠各6只。低氧和治疗组小鼠在10% 氧浓度条件下进行饲养,治疗组小鼠饮水中加入10 mmol/L 4-羟基-2, 2, 6, 6-四甲基哌啶(TEMPOL)进行干预。比较各组小鼠肺小动脉重塑(MT%)及右心室肥厚指标的变化;ELISA 法检测各组肺组织ROS 浓度的变化;RT-PCR 法检测各组肺组织NOX2、4 及eNOS 基因表达的变化。结果 野生型及基因敲除低氧组小鼠肺血管重塑及右心室肥厚指标较常氧组和治疗组均明显上升(P<0.05),而治疗组和常氧组间比较差异无统计学意义(P>0.05)。野生型低氧及治疗组小鼠肺组织ROS浓度均低于常氧组(P<0.05),而低氧组和治疗组间比较差异无统计学意义(P>0.05)。野生型低氧组小鼠eNOS、NOX2 和NOX4 的mRNA 表达较常氧组均显著上升(P<0.05),TEMPOL 干预可逆转上述指标的过度表达。基因敲除常氧组小鼠NOX2 和NOX4 mRNA 表达高于同组野生型小鼠(P<0.05);慢性缺氧后NOX4 mRNA表达较常氧组差异无统计学意义(P>0.05),NOX2 mRNA 表达较常氧组显著下降(P<0.05);治疗组NOX2mRNA 表达较低氧组进一步下降,而NOX4 mRNA 表达较低氧组明显上升(P<0.05)。结论 eNOS 是低氧条件下NOX2、4 表达的重要调控因素,eNOS 和NOX 在低氧性肺血管重塑过程中可能有着重要的联系。     

Inhalation of hydrogen gas attenuates cisplatin-induced ototoxicity via reducing oxidative stress

Objective

Cisplatin, an anticancer drug used extensively to treat a broad range of tumors, has strong ototoxic side effects induced by reactive oxygen species (ROS). Recently, it has been reported that hydrogen gas (H₂) is a new antioxidant by selectively reducing hydroxyl radical, the most cytotoxic ROS. The present study was designed to investigate whether H₂ treatment is beneficial to cisplatin-induced ototoxicity via reducing oxidative stress.

Methods

The animals were intraperitoneally given a 30 min infusion of 16 mg/kg cisplatin or the same volume of saline. H₂ treatment was given twice with 2% H₂ inhalation for 60 min starting at 1 h and 6 h after cisplatin or saline injection, respectively. The hearing status of all animals was evaluated by auditory brainstem responses (ABR). The hair cell damage was observed by phalloidin staining. In addition, the levels of oxidative products in serum and cochlear tissue were measured.

Results

We found that H₂ treatment significantly attenuated cisplatin-induced hearing loss evaluated by click-evoked and tone burst ABR threshold. Furthermore, histological analysis revealed that 2% H₂ treatment significantly alleviated cisplatin-induced hair cell damage in the organ of corti. In addition, cisplatin significantly increased the levels of malondialdehyde (MDA) and 8-iso-prostaglandin F2α (8-iso-PGF2α) in serum and cochlear tissue, which was attenuated by H₂ treatment.

Conclusion

These results demonstrate that H₂ is beneficial to cisplatin-induced ototoxicity via reducing oxidative stress. Therefore, H₂ has potential for improving the quality of life of patients during chemotherapy by efficiently mitigating the cisplatin ototoxicity.     

脑型疟疾免疫病理机制的实验研究：肿瘤坏死因子的作用

本文以化学发光法（ＣＬ）、诱化学发光法（ＩＣＬ）、红细胞变形性（ＥＤ）检测等方法研究了感染伯氏疟原虫（Ｐｌａｓｍｏｄｉｕｍｂｅｒｇｈｅｉ）Ａｎｋａ株的ＢＡＬＢ／ｃ小鼠在注射重组肿瘤坏死因子（ｒＴＮＦ）以后引起脑型疟疾（ＣＭ）时其血浆中活性氧（ＲＯＳ）及相关自由基与ＥＤ及ＥＤ与ＣＭ间的关系。结果发现在ＣＭ出现时动物血浆中ＲＯＳ及相关自由基水平明显增高，ＥＤ明显降低。使用抗氧化剂可以明显改善上述过程而使ＣＭ发生率下降。作者认为，疟原虫感染时ＴＮＦ的过量产生可使宿主吞噬细胞释放大量ＲＯＳ及相关自由基，血浆中这些物质的大量聚集使红细胞变形能力受到破坏，这时红细胞在通过具有极丰富血循环的脑组织时在脑微血管内易于形成广泛性微拴塞，导致ＣＭ形成。     

DJ-1与子痫前期关系的研究进展

DJ-1又名帕金森病蛋白7（ Parkinson disease protein 7,PARK7）属于ThiJ/PfpI/DJ-1超家族,DJ-1是一种抗氧化剂,抗氧化应激是其主要功能,近年研究发现DJ-1在子痫前期（preeclampsia,PE）患者胎盘组织中表达水平升高,推测 DJ-1通过氧化应激途径参与子痫前期的发生发展。子痫前期是妊娠期特有疾病,是导致孕产妇和新生儿发病率和死亡率增高的主要原因。但子痫前期的病因和发病机制尚在研究探讨,其中氧化应激损伤参与子痫前期的发生发展是其中研究的一个热点,就DJ-1在子痫前期中的作用机制进行综述。