CYP27B1基因突变所致维生素D依赖性佝偻病ⅠA型患儿临床特征与基因分析

目的探讨维生素D依赖性佝偻病(VDDR)ⅠA型患儿的临床特征,以及CYP27B1基因突变情况。方法选择2019年3月至12月,于首都儿科研究所附属儿童医院内分泌科确诊为VDDRⅠA型的2例患儿(患儿1、2)为研究对象。采用回顾性研究方法,①分析其临床表现,基因检测、治疗、转归及随访结果等。②对2例患儿检出的新突变,采用MutationTaster、SIFT、PROVEAN、Polyphen-2等蛋白质功能预测软件,预测该基因新突变的致病性。按照2015年美国医学遗传学与基因组学学会(ACMG)制定的《ACMG遗传变异分类标准与指南》,对该基因新突变致病性进行分级。③通过比对8种灵长类及100种脊椎动物CYP27B1基因编码蛋白质序列,判断新突变位点在不同物种中的保守性。④利用Rosetta软件,对CYP27B1基因新突变后编码蛋白质建立同源3D模型,分析突变前、后蛋白质结构。本研究经首都儿科研究所伦理委员会批准(审批文号:首都儿科研究所SHERLL2020003)。结果①一般临床资料:患儿1、2均为男性患儿,年龄分别为5岁7个月和1岁8个月,分别因为双下肢畸形3年及走路始步态不稳8个月,于病例收集医院住院治疗。②入院查体:身高均低于同性别、年龄健康儿童,均存在肋下缘、双膝关节外翻,双下肢呈X型。患儿1存在方颅畸形、鸡胸、肋骨串珠样改变。③入院时实验室及影像学检查:血钙、磷均降低,25-羟维生素D3[25(OH)-D3]稍低(患儿1)或正常(患儿2),碱性磷酸酶(ALP)、甲状旁腺素(PTH)均明显升高。腕、膝关节X射线摄片检查均可见尺、桡骨干骺端先期钙化带不规则,放射冠征、杯口征等佝偻病特征性改变。④基因检测:患儿1存在CYP27B1基因c.1358G>A与c.184C>T复合杂合突变;患儿2存在c.1325_1326insCCCACCC纯合突变,均遗传自其父母,被确诊为VDDRⅠA型。⑤治疗及随访:对2例患儿采取骨化三醇及钙剂口服治疗后分别随访15个月和22个月,佝偻病相应症状、体征好转,出现追赶生长,实验室及影像学指标恢复正常,可见干骺端光整。⑥新突变致病性及其分级:CYP27B1基因c.184C>T在人类基因突变数据库(HGMD)(http://www.hgmd.cf.ac.uk)中尚未收载,为新突变。采用MutationTaster、SIFT、PROVEAN、Polyphen-2蛋白质功能预测软件分析发现,该新突变具有致病性;根据《ACMG遗传变异分类标准与指南》,该新突变被判断为可能致病性突变。⑦新突变位点在不同物种中的保守性分析:对CYP27B1基因该新突变位点编码蛋白质序列,在8种灵长类及100种脊椎动物中的保守性分析发现,该位点高度保守。⑧新突变前、后编码蛋白质三维结构分析:采用Rosetta软件对CYP27B1基因c.184C>T突变前、后编码蛋白质同源3D模型发现,该位点突变后,第62位氨基酸由组氨酸突变成酪氨酸后,增加了与第491位苏氨酸残基的极性相互作用,可能引起编码蛋白质结构变化。结论对于血钙、磷均降低,伴有PTH升高,25(OH)-D3非明显降低患儿,需考虑VDDRⅠA型可能,应采取CYP27B1基因检测确诊。如果CYP27B1基因c.184C>T突变后续被HGMD证明是新突变,则本研究将丰富CYP27B1基因突变类型。     

Agonist binding and activation of the rat beta(1)-adrenergic receptor: role of Trp(134(3.28)), Ser(190(4.57)) and Tyr(356(7.43))

We investigated the role of Trp(134(3.28)), Ser(190(4.57)) and Tyr(356(7.43)) in agonist binding to, and activation of, the rat beta(1)-adrenergic receptor by comparing pK(i)s and functional responses of W134A, S190A and Y356F mutant receptors to wild type, all stably expressed in CHO cells. All three mutations significantly (P < 0.05) reduced adenylyl cyclase intrinsic activity (IA) compared to wild type in response to stimulation with both (-)-isoprenaline (53-88%) and (-)-RO363 (46-61%), and there was no significant correlation either between IA or pD(2) and pK(i) (P > 0.4), suggesting that changes in pK(i) were not sufficient to explain the fall in adenylyl cyclase activity. The most pronounced reduction in affinity (126-fold, P < 0.01) was displayed by xamoterol for the Y356F mutation, suggesting that xamoterol is able to directly interact with Tyr(356(7.43)). For the other agonists, the change in pK(i) values for the mutant receptors ranged from a 20-fold decrease to a 2-fold increase compared to the wild type. In a three-dimensional model of the rat beta(1)-adrenergic receptor, Trp(134(3.28)) and Tyr(356(7.43)) form part of a hydrophobic binding pocket involving residues in transmembrane helices 1, 2, 3 and 7. Our results suggest that Trp(134(3.28)) and Tyr(356(7.43)), together with Trp(353(7.40)), are able to interact via pi-pi interactions to stabilize the extracellular ends of transmembrane helices 3 and 7. Ser(190(4.57)) appears to be involved in a hydrogen bonding network, which maintains the spatial relationship between transmembrane helices 3 and 4. These interhelical interactions suggest that the three mutated residues stabilize the active receptor state by maintaining the proper packing of their respective transmembrane helix within the helix bundle, facilitating the appropriate movement and rotation of the transmembrane regions during the activation process.     

Wnt inhibitors Dkk1 and Sost are downstream targets of BMP signaling through the type IA receptor (BMPRIA) in osteoblasts

The bone morphogenetic protein (BMP) and Wnt signaling pathways both contribute essential roles in regulating bone mass. However, the molecular interactions between these pathways in osteoblasts are poorly understood. We recently reported that osteoblast‐targeted conditional knockout (cKO) of BMP receptor type IA (BMPRIA) resulted in increased bone mass during embryonic development, where diminished expression of Sost as a downstream effector of BMPRIA resulted in increased Wnt/β‐catenin signaling. Here, we report that Bmpr1a cKO mice exhibit increased bone mass during weanling stages, again with evidence of enhanced Wnt/β‐catenin signaling as assessed by Wnt reporter TOPGAL mice and TOPFLASH luciferase. Consistent with negative regulation of the Wnt pathway by BMPRIA signaling, treatment of osteoblasts with dorsomorphin, an inhibitor of Smad‐dependent BMP signaling, enhanced Wnt signaling. In addition to Sost, Wnt inhibitor Dkk1 also was downregulated in cKO bone. Expression levels of Dkk1and Sost were upregulated by BMP2 treatment and downregulated by Noggin. Moreover, expression of a constitutively active Bmpr1a transgene in mice resulted in the upregulation of both Dkk1 and Sost and partially rescued the Bmpr1a cKO bone phenotype. These effectors are differentially regulated by mitogen‐activated protein kinase (MAPK) p38 because pretreatment of osteoblasts with SB202190 blocked BMP2‐induced Dkk1 expression but not Sost. These results demonstrate that BMPRIA in osteoblasts negatively regulates endogenous bone mass and Wnt/β‐catenin signaling and that this regulation may be mediated by the activities of Sost and Dkk1. This study highlights several interactions between BMP and Wnt signaling cascades in osteoblasts that may be amenable to therapeutic intervention for the modification of bone mass density. © 2010 American Society for Bone and Mineral Research     

急性分离的大鼠海马及皮层神经元快速失活钾电流特性的比较

目的 探讨海马及皮层神经元细胞膜上快速失活钾通道的特性。方法 急性分离大鼠海马及皮层神经元;利用whole-cell膜片钳技术记录IA电流。结果 海马神经元上的IA通道电流幅度较皮层神经元大、潜伏期短。结论 海马神经元与皮层神经元上的IA电流特征存在差别。     

A comparative study of the effects of mercury compounds on cell viability and nucleic acid synthesis in HeLa cells

The effects of various mercury compounds on HeLa cell viability and DNA and RNA syntheses in intact cells and in isolated nuclei have been studied. The compounds examined were: methylmercuric chloride, ethylmercuric chloride, dimethylmercury, phenylmercuric acetate, p-hydroxymercuribenzoate, p-hydroxymercuribenzenesulfonate, HgCl2, HgSO4 , Hg(ClO4)2 and Hg2(ClO4)2. All of the compounds except dimethylmercury inhibited colony formation as well as DNA synthesis in intact cells and in isolated nuclei. RNA synthesis in intact cells was inhibited by all the compounds except dimethylmercury, p-hydroxymercuribenzoate and Hg(ClO4)2. In isolated nuclei, alpha-amanitin-resistant RNA synthesis was inhibited by all the compounds except dimethylmercury, alpha-Amanitin-sensitive RNA synthesis was stimulated by some compounds, inhibited by some, and unaffected by others. The effects of two non-mercurial sulfhydryl reagents, N-ethylmaleimide and iodoacetic acid, were also examined. These compounds showed a pattern of effects on nucleic acid synthesis which differed considerably from that of the mercury compounds. Neither compound significantly inhibited alpha-amanitin-resistant RNA synthesis in isolated nuclei, although both inhibited RNA synthesis in intact cells. Iodoacetic acid had no inhibitory effect on DNA synthesis in isolated nuclei but strongly inhibited DNA synthesis in intact cells.     

Lymph node metastasis and lymph vascular space invasion in microinvasive squamous cell carcinoma of the uterine cervix

The objective of this study was to determine whether the depth of invasion was related to lymph vascular space invasion (LVSI) and lymph node metastasis and whether there was a correlation between LVSI and lymph node metastasis in stage IA cervical cancer. The medical records, including surgical notes and pathologic reports, of 202 patients with microinvasive squamous cell carcinoma of the uterine cervix were reviewed retrospectively. There was a positive correlation between the depth of invasion and the LVSI, and the incidence of lymph node metastasis was slightly higher than those reported hitherto for stage IA1 cervical cancer, especially in the depth of invasion of 1-3 mm group. However, among four patients with lymph node metastasis, only two patients had positive LVSI. There was no definite correlation between LVSI and lymph node metastasis. LVSI could not identify the patients with high risk for lymph node metastasis.     

A case of influenza-associated invasive aspergillosis with cerebral hemorrhage due to infectious vasculopathy

An invasive aspergillosis (IA) primarily occurs among immunocompromised patients. Recently with an influenzae infection prevalently spreading, influenzae-associated invasive aspergillosis (IAIA) has been reported occasionally. By contrast, neuroleptic malignant syndrome (NMS) occurs rarely in psychiatric patients who are treated with Olanzapine. We report a 43 years old male with psychiatric disorder who had developed IAIA followed by NMS and cerebral hemorrhage as the result of aspergillus invasion to cerebral vessels. He had also super-infection of COVID-19, 13 months later to be saved completely after invasive mechanical respiratory supports. From clinical aspects, we would emphasize that it is of importance to find earlier co-occurrence of IAIA patients with cerebral hemorrhage due to secondary infectious vasculopathy of IA.     

The immunosuppressive agents rapamycin,cyclosporin A and tacrolimus increase lipolysis,inhibit lipid storage and alter expression of genes involved in lipid metabolism in human adipose tissue

Cyclosporin A (CsA), tacrolimus and rapamycin are immunosuppressive agents (IAs) associated with insulin resistance and dyslipidemia, although their molecular effects on lipid metabolism in adipose tissue are unknown.