Differential association of phosphatases with hematopoietic co-receptors bearing immunoreceptor tyrosine-based inhibition motifs

A novel family of inhibitory co-receptors has been recently defined according to the presence in their intracytoplasmic domain of immunoreceptor tyrosine-based inhibition motifs (ITIM). In particular, this family includes a low-affinity receptor for IgG, FcγRIIB, which is widely expressed on hematopoietic cells, as well as killer cell inhibitory receptors (KIR) for major histocompatibility complex (MHC) class I proteins, expressed on both T and natural killer (NK) lymphocytes. FcγRIIB and KIR inhibitory function depends upon the tyrosine phosphorylation of their respective ITIM. Phosphorylated FcγRIIB and KIR ITIM bind the tandem SH2 tyrosine phosphatases, SHP-1 and SHP-2. Recently, FcγRIIB has been shown to associate with a polyphosphate inositol 5-phosphatase, SHIP, which appears to be involved in its inhibitory function. Using cell lysate adsorption to phosphorylated ITIM peptides and surface plasmon resonance, we demonstrate here that, in contrast to FcγRIIB, KIR (CD158b: p58.2) do not bind to SHIP, and only recruit SHP-1 and SHP-2. In addition, we show that point mutation of the amino acid residue in position tyrosine-2 of FcγRIIB and KIR ITIM abolihes their binding to SHP-1 and SHP-2, but leaves intact the association of SHIP with FcγRIIB ITIM. These data contribute to the structural definition of ITIM and document a differential recruitment of phosphatases by distinct ITIM. These findings also reveal that diverse strategies of inhibition are used by distinct members of the ITIM-bearing co-receptor family.     

Induction of a low voltage-activated,fast-inactivating Ca2+ channel in cultured bone marrow stromal cells by dexamethasone

The production of biochemical markers associated with the osteoblastic phenotype, and accompanying changes in the expression of voltage-operated Ca²⁺ channels, have been examined in rat bone marrow stromal cell cultures treated with dexamethasone (10^-8 M). Whole cell clamp analysis of voltage-operated Ca²⁺ channels in control cultures (using Ba²⁺ as the charge carrier) revealed primarily a high voltage-activated (HVA), slowly inactivating current, which was enhanced two- to threefold by treatment of the cells with Bay K 8644 (300 nM) and inhibited by nifedipine (4 M). In dexamethasone-treated cultures, the I–V relationship for inward current was shifted to more positive potentials in comparison with control cells. Most cells in these cultures possessed both the HVA current and also a faster inactivating, low-voltage-activated (LVA), nifedepineresistant current. These two currents could be separated both by nifedipine and by the use of steady state inactivation of the LVA current. The two components of the Ba²⁺ current varied widely in their relative size. The combination of LVA and HVA currents seen in dex-induced stromal cells resembles records of voltage-operated Ca²⁺ channels from cultures of calvarial osteoblasts.     

抑癌基因PTEN在口腔涎腺腺样囊性癌组织中的表达

目的　从蛋白水平研究抑癌基因 10号染色体缺失的磷酸酯酶及张力蛋白同源物 (PTEN ) ,在口腔涎腺腺样囊性癌中表达及其意义。方法　采用免疫组织化学方法检测 3 4例腺样囊性癌 (其中筛孔型 14例 ,管状型 11例 ,实体型 9例 )组织中PTEN的表达。结果　 3 4例腺样囊性癌PTEN蛋白表达阴性率为 17.6% ( 6/ 3 4) ,筛孔型、管状型、实体型表达阳性率分别为 14 .3 % ( 2 /14 ) ,18.2 % ( 2 / 11)和 2 2 .2 % ( 2 / 9) ,各型之间阳性率无显著性差异 (P >0 .0 5 )。结论　涎腺腺样囊性癌组织中存在抑癌基因PTEN表达缺失 ,PTEN在部分腺样囊性癌病变发展中起作用 ,PTEN表达异常与腺样囊性癌分型以及临床病理特征无关     

关龙胆地上部分保肝作用研究

目的通过不同毒物引起的肝损伤来研究关龙胆地上部分的保肝作用。方法选用D-半乳糖胺、硫代乙酰胺、四氯化碳等3个肝损伤毒物造肝损伤模型,通过不同机制引起的肝损伤来研究关龙胆地上部分的保肝作用。结果关龙胆地上部分有一定的保肝作用,可降低各种肝损伤模型的ALT,AST,AKP等。结论关龙胆地上部分也有一定的药用价值,用全草取代地下部分入药有一定的可行性。     

微小RNA-21调控同源性磷酸酶-张力蛋白基因表达在子痫前期发病中的作用机制

目的 探究微小RNA-21(miR-21)在子痫前期(PE)病人发病中的表达变化及可能作用机制.方法 收集2016年8月至2019年10月郑州市妇幼保健院收治的45例PE病人及45例匹配正常孕妇胎盘组织,采用实时定量PCR(RT-qPCR)法检测miR-21相对表达水平.体外培养人滋养层细胞系HTR-8/SVneo,转...     

子宫内膜癌PTEN蛋白表达及其临床意义

目的 :探讨抑癌基因第 10染色体同源丢失性磷酸酶 -张力蛋白基因 (PTEN)蛋白表达与子宫内膜癌的发生、发展及复发的关系。方法 :采用免疫组织化学S P法检测PTEN蛋白在 5 0例子宫内膜癌、12例不典型增生子宫内膜及 10例正常子宫内膜组织的表达。结果 :5 0例子宫内膜癌中PTEN蛋白表达率为 5 6 0 0 % ,明显低于正常子宫内膜以及不典型增生子宫内膜中的表达 (10 0 0 0 %、91 0 0 % ) (P <0 0 5 )。PTEN蛋白在无肌层浸润或肌层浸润≤ 1/ 2的子宫内膜癌中阳性表达率为 76 0 0 % ,肌层浸润 >1/ 2或有淋巴结转移者为 36 0 0 % ,与肌层浸润程度显著相关 (P <0 0 5 ) ,且Ia Ib期与Ic期相比也有统计学差异 ;但与子宫内膜癌的组织学分级、有无复发无关 (P >0 0 5 )。结论 :抑癌基因PTEN蛋白表达缺失在子宫内膜癌的发生、发展、浸润及复发过程中有一定作用。     

肝再生磷酸酶3在恶性血液病中的研究进展

正肝再生磷酸酶3(phosphatase of regenerating liver-3,PRL-3)是蛋白酪氨酸磷酸酶家族的一员。蛋白酪氨酸磷酸酶家族有107个成员,它们通过将底物去磷酸化从而参与某些信号通路,被认为在肿瘤的发生和发展过程中发挥了一定的作用。2001年,Saha等~([1])通过基因表达系列分析(serial analysis of gene expression,SAGE)的方法发现,相对于原发病     

Analysis of PTEN Gene Mutations in Korean Patients With Cowden Syndrome and Polyposis Syndrome

PURPOSE PTEN (phosphatase and tensin homologue deleted in chromosome 10) is a candidate tumor suppressor gene. Mutations of this gene are responsible for PTEN hamartoma tumor syndromes, including Cowden syndrome, Bannayan-Riley-Ruvalcaba syndrome, Proteus syndrome, and Proteus -like syndromes. Recently, PTEN mutations were identified in several human neoplasms. We analyzed the DNA of various organs and lesions in Korean patients with Cowden syndrome, their family members, and patients with familial adenomatous polyposis for germline or somatic PTEN mutations.METHODS The 11 patients included in this study were 5 patients with Cowden syndrome, 4 of their family members, and 2 patients with familial adenomatous polyposis. Deletions and mutations in exons 1 to 9 of the PTEN gene were evaluated by polymerase chain reaction-single strand conformation polymorphism and sequencing analysis in esophageal acanthosis, gastric polyps, colonic polyps, skin lesions, and peripheral blood mononuclear cells. To exclude common polymorphisms, 240 controls were tested.RESULTS All patients with Cowden syndrome showed several to numerous polyps in the gastrointestinal tract. A missense mutation at codon 217 (GTC to GAC, Val to Asp) in exon 7 was identified in one Cowden syndrome patient, and a nonsense mutation at codon 211 (TGC to TGA, Cys to stop) in exon 6 was identified in a second patient. Identical mutations were found in all tissue samples, including colonic polyps, from each patient. No PTEN mutations were found in their family members or in any patient with familial adenomatous polyposis. None of tested controls contained a mutation.CONCLUSIONS We have identified two new germline PTEN mutations in Korean patients with Cowden syndrome. Mutations in the introns and regulatory regions of the PTEN gene may be present in additional patients with Cowden syndrome and polyposis syndrome.Supported by a grant (Grant number 2003-261) from the Asan Institute for Life Sciences, Seoul, Korea.Reprints are not available.Presented at the meeting of International Gastrointestinal Bioregulation Conference, Hyogo, Japan, March 27, 2004.     

老年男性各年龄组骨密度与骨代谢生化指标的关系

目的　测定老年男性不同年龄组骨密度及血、尿中与骨吸收和骨形成有关的生化指标 ,观察其与年龄的关系 ,探讨以上生化指标对早期诊断原发性骨质疏松的临床意义。方法　采用双能量 X线骨密度测定仪测定前臂骨密度 ;采用全自动生化分析法测定血清碱性磷酸酶(ALP)、尿钙 (Ca)、肌酐 (Cr) ;采用放免法测定骨钙素 (BGP)、抗酒石酸酸性磷酸酶 (TRAP)、尿羟脯氨酸 (HOP)。将年龄 60～ 95岁的老年男性 97例分为 60～ 69岁、 70～ 79岁和 80岁以上三组并与 60岁以下男性进行比较。再将其分为骨质疏松组与非骨质疏松组 ,比较其测定值。结果　老年男性骨密度及骨形成与骨吸收指标呈现随着年龄增长而降低的趋势。其中 ,骨质疏松组较非骨质疏松组骨钙素 (BGP)、抗酒石酸酸性磷酸酶 (TRAP)、尿羟脯氨酸 (HOP) ,明显下降 (P<0 . 0 5)。结论　老年男性骨质疏松属于低转换型 ,骨转换指标随增龄而呈下降趋势     

Hypocalcemia response following calcitonin administration: Lack of correlation with osteoclast number determined after histoenzymologic identification in osteoprorosis

Summary The relationship between calcitonin-induced hypocalcemia and histomorphometric parameters of bone resorption was examined in iliac crest biopsies of 30 osteoporotic patients aged 55–86 years all of whom had received a single injection of 100 UI of salmon calcitonin. Number of osteoclasts and active resorption surfaces were determined after histoenzymologic staining based on osteoclastic tartrate resistant acid phosphatase content. No significant correlation could be demonstrated between the drop of hypocalcemia and the different histomorphometric parameters. It can be concluded that the calcitonin test is useless in osteoporosis.