Dopamine D2 receptor gene expression in human adenohypophysial adenomas

The inhibitory effects of dopamine on adenohypophysial cells are mediated via dopamine subtype 2 receptor (D2R). Dopamine agonists inhibit hormone release and induce tumor shrinkage in most prolactin-secreting adenomas, whereas in other adenoma types such effects are sporadic. We investigated D2R gene expression by in situ hybridization (ISH) and immunocytochemistry in different types of pituitary adenomas. By ISH, a variable D2R signal was detected in 79 of 89 cases: 4 of 6 densely granulated and 8 of 8 sparsely granulated somatotroph, 4 of 4 mammosomatotroph, 7 of 7 mixed somatotroph-lactotroph, 4 of 4 acidophil stem cell, 16 of 16 sparsely granulated lactotroph, 11 of 16 corticotroph (functioning and silent), 3 of 4 silent subtype 3, 5 of 5 thyrotroph, 5 of 6 gonadotroph, 5 of 6 null cell, and 7 of 7 oncocytic adenomas. By immunocytochemistry, D2R protein was localized in cytoplasm and nuclei of 60 of 62 adenomas. In lactotroph adenomas, long-acting bromocriptine (BEC-LAR) induced a major increase in D2R mRNA, which was not accompanied by increased D2R immunoreactivity, suggesting mRNA stabilization. In conclusion, D2R gene is expressed in the majority of pituitary adenomas representing all tumor types. The significance of nuclear localization of D2R protein remains to be clarified.     

雄激素和雄激素受体对肝癌细胞株PEG10表达的作用

目的 探讨雄激素和雄激素受体(AR)对肝癌细胞株PEG10表达的调控作用.方法 设计合成针对人ARsiRNA,并转染HepG2和7404肝癌细胞株.用双氢睾丸酮(DHT)干预HepG2细胞.Western Blot检测AR和PEG10表达水平.结果 从3对AR siRNA中筛选到1对siRNA(AR siRNA-3),它在2种肝癌细胞株中均可有效抑制AR的表达,其抑制作用呈剂量依赖关系.2种肝癌细胞株中,浓度为240 nmol/L的AR siRNA-3在转染后24 h,对AR抑制效率可达80%以上,且抑制效果可持续至72 h.AR siRNA-3转染24h后PEG10表达水平降低,转染48 h后,PEG10表达水平降低非常明显,72 h后PEG10表达有所上升.DHT可促进HepG2细胞PEG10的表达,呈剂量依赖关系.DHT对AR表达未见明显作用.结论 雄激素和AR参与了肝癌细胞株PEG10表达的调控.这可能是男性肝细胞癌发病率较高的原因之一.     

Gonadotropin-releasing hormone receptor gene expression in rat anterior pituitary

Gonadotropin-releasing hormone (GnRH) effects on the lactotroph function have been widely studied, but they probably result from paracrine interactions. No visual data about GnRH receptor in the pituitary are available. In order to identify the GnRH target cells in the pituitary of adult rats, the cellular distribution of rat GnRH receptor mRNA was investigated by electron microscopy, usingin situ hybridization on ultrathin pituitary frozen sections.In situ hybridization was performed using a digoxigenin-labeled oligonucleotide probe revealed by an indirect immunogold reaction. Gonadotropin-releasing hormone receptor mRNA was found in the cytoplasmic matrix, apposed to the endoplasmic reticulum and the nucleus of the gonadotrophs, which were identified by their ultrastructural characteristics, and by the presence of luteinizing hormone (LH) immunoreactivity. It was also found in the lactotrophs, which were revealed by the immunocytological detection of prolactin. No GnRH receptor mRNA was detected in corticotrophs, somatotrophs, thyrotrophs or hepatocytes. This result, without excluding paracrine effects, clearly showed that in addition to the gonadotrophs, the lactototrophs are likely to be direct target cells for the hypothalamic GnRH.     

雄激素受体在脑膜瘤中的表达及其临床意义

目的观察33例脑膜瘤患者肿瘤组织中雄激素受体（AR）的表达,探讨AR的表达与脑膜瘤临床病理的相关性。方法应用免疫组化SP法及原位杂交法检测脑膜瘤组织标本中AR的表达情况。结果AR在恶性脑膜瘤组中的染色强度明显高于良性脑膜瘤组,其平均积分光密度值（IOD）分别是25.41±13.42和6.20±4.75（P〈0.05）;AR mRNA的IOD分别为19.46±9.33和4.72±4.68（P〈0.05）。结论AR在脑膜瘤的表达与肿瘤细胞的病理性质（良、恶性）有关,AR可作为鉴别良恶性脑膜瘤的辅助诊断指标。     

Dopamine D2 receptor stimulation alters G-protein expression in rat pituitary intermediate lobe melanotropes

Stimulation of dopamine D₂ receptors inhibits melanotrope pro-opiomelanocortin (POMC) biosynthesis and α-melanocyte-stimulating hormone (MSH) secretion. These effects are mediated by G-protein α_i- and α_o- subunits and are reversed by stimulating receptors linked to activation of Gα_s protein. Melanotrope activity is increased by haloperidol, a D₂ receptor antagonist, and decreased by bromocriptine, a D₂ receptor agonist. Both the short and long isoforms of the D₂ receptor mRNA and protein increase following chronic haloperidol treatment. After chronic bromocriptine treatment the short isoform is downregulated, whereas the long isoform is upregulated (1). Our hypothesis is that specific G protein α-subunits alter in pattern of expression similarly to the receptor isoforms. Using immunohistochemistry andin situ hybridization, this study examined changes in Gα_i' Gα_0', and Gα_s protein and mRNA expression following chronic treatments with bromocriptine or haloperidol. Gα_i3 and Gα_o immunoreactivities increased following bromocriptine treatment, whereas Gα_s and Gα_i1/2 did not change. G_s immunoreactivity increased after haloperidol treatment, whereas Gα_i1/2,Gα_i3 and Gα_o did not change. Gα_i and Gα_o mRNA increased following bromocriptine and decreased following haloperidol treatments, whereas the inverse results were observed with Gα_s mRNA. These results suggest D₂ receptor activation can specifically increase Gα_i3 and Gα_o expression, and D₂ receptor blockade increases Gα_s expression.     

Vimentin mRNA expression increases after corticospinal axotomy in the adult hamster

We examined changes in vimentin gene expression during Wallerian degeneration after corticospinal axotomy in the adult hamster. Vimentin, which is the product of a type III intermediate filament (IF) gene, is expressed in various cells of mesenchymal origin, including microvascular endothelial cells, microglia and developing astrocytes. While increases in vimentin protein have been observed after various types of central nervous system (CNS) injury, it is not known whether this increase is due to increased vimentin mRNA expression. There is also conflicting evidence as to which cells are expressing increased levels of vimentin. In the present study we usedin situ hybridization and double-label immunofluorescence techniques to address these issues. A³⁵S-labeled vimentin cDNA probe was used forin situ hybridizations of brain stem sections obtained 2, 7 and 14 days after unilateral transection of the corticospinal tract in the caudal medulla of adult hamsters. Autoradiography showed that an increase in vimentin mRNA associated with the degenerating corticospinal tract occurred by 2 days after axotomy and that the levels remained elevated for at least 14 days. Immunoblotting and immunocytochemical studies indicated that vimentin protein levels were increased in the degenerating corticospinal tract. Double-label immunofluorescence revealed many vimentin-positive cells and processes that were also labeled with GFAP antibody. In addition, cells and processes that were vimentin-negative but GFAP-positive were also found in the degenerating tract. We suggest that the reactive cells which possessed both vimentin and GFAP were reactive astrocytes of astroblastic origin while those that expressed only GFAP were derived from mature astrocytes. Other vimentin-positive cells/processes did not label with anti-GFAP and thus were either microglial, endothelial or inflammatory cells. These results demonstrate that an increase in vimentin mRNA occurs during Wallerian degeneration after corticospinal axotomy and that this increase is likely to be due to contributions from more than one cell type.     

The role of androgens and the androgen receptor in cycling endometrium

Androgens and the androgen receptor (AR) are not only required for male reproductive function, they are also essential for female reproductive physiology. Widely expressed in female reproductive tissues, AR levels fluctuate in a regulated manner in the cycling endometrium. Female androgen production depends on the adrenal glands and expression of key enzymes in the endometrium that facilitate local androgen biosynthesis and conversion. Moreover, levels of circulating androgens, in women of reproductive age, fluctuate in a cycle-dependent manner and a mid-cycle peak is associated with conception. AR and androgen signalling have a decisive role in the differentiation of human endometrial stromal cells into decidual cells. Compelling evidence for androgen signalling in the regulation of endometrial function pertaining to implantation and pregnancy is provided by epidemiological studies demonstrating a strong association between polycystic ovary syndrome, premature ovarian failure or advanced maternal age and adverse pregnancy outcome. Thus, androgen signalling is an essential component of normal endometrial physiology and its perturbation is associated with reproductive failure.     

Changes in androgen receptor mRNA expression in the forebrain and oviduct during the reproductive cycle of female leopard geckos,Eublepharis macularius

Successful reproduction requires the coordination of reproductive physiology with behavior. The neural correlates of reproductive behavior have been elucidated in a variety of amphibians, mammals, and birds but relatively few studies have examined reptiles. Here we investigate differences in androgen receptor (AR) mRNA expression in the forebrain and oviduct between previtellogenic and late vitellogenic female leopard geckos, Eublepharis macularius. Plasma concentrations of testosterone (T) are low when females are previtellogenic and sexually unreceptive but increase dramatically during late vitellogenesis when females are receptive. In addition, receptivity can be induced by treatment with exogenous T. The relative abundance of AR-mRNA across various nuclei was greater in late vitellogenic than in previtellogenic females. This general pattern was observed in the medial preoptic area, anterior hypothalamus, external nucleus of the amygdala, dorsolateral aspect of the ventromedial hypothalamus, lateral septum, and periventricular hypothalamus. There were also clear differences in AR-mRNA expression among these nuclei. The pattern of gene expression observed in the brain was reversed within stromal cells of the oviduct where expression of AR-mRNA decreased from the previtellogenic stage to the late vitellogenic stage. Overall, these data demonstrate that T concentration in the plasma, abundance of AR-mRNA in the brain and oviduct, and sexual behavior change coordinately during the reproductive cycle of female leopard geckos. Although the function of AR in the female leopard gecko is not yet clear, our results are in accord with growing evidence that androgens regulate numerous aspects of female physiology and behavior in vertebrates.     

The expression of transforming growth factor-beta and interleukin-1beta mRNA and the response to 1,25(OH)2D3' 17 beta-estradiol, and testosterone is age dependent in primary cultures of mouse-derived osteoblasts in vitro

The aim of the present study was to examine the hypothesis that primary cultures of osteoblasts obtained from bones of young animals respond to hormones better than cell cultures obtained from old animals. We studied in cultured osteoblastic cells the effects of 1,25(OH)2D3 and sex steroid hormones on several mouse osteoblastic phenotypic expressions including transforming growth factor-beta (TGF-beta) and interleukin-1beta (IL-1beta) mRNAs. Second passages of long bone-derived osteoblastic cells from young donors (5-12 wk) and old donors (10-12 mo old) were used for this study. The cells obtained from old animals had decreased ALP activity and cAMP compared with cells obtained from young animals with no change in collagen production and mineralization. The addition of 17beta-estradiol and testosterone increased ALP activity and mineralization in the cultured cells from both age groups and collagen production in cells obtained from old mice. Using in situ hybridization IL-1beta and TGF-beta mRNA expression was observed to be higher in the osteoblasts from young than from old donors. 1,25(OH)2D3 increased IL-1beta mRNA expression in the cells derived from young mice. Testosterone and 17beta-estradiol inhibited IL-1beta mRNA expression only in cells derived from young mice. Sex steroid hormones did not change TGF-beta mRNA expression in any of the cell lines, but 1,25(OH)2D3 increased its expression in cells derived from old donors. The results of the present study indicate that cells obtained from old mice are generally less active than those obtained from young animals.     

Differential expression and cellular localization of activin and inhibin mRNA in the rainbow trout ovary and testis

An inhibin cDNA from rainbow trout consisted of 1305 bp, which coded for 352 amino acid residues. The deduced amino acid sequence of mature inhibin was 50 to 60% identical to mammalian sequences. Distribution of inhibin alpha and activin beta A and beta B in different ovarian and testis compartments was studied in rainbow trout by in situ hybridization with complementary RNA probes. In testis tissue, inhibin alpha and activin beta A and beta B were expressed only in the testicular interstitia between the seminal lobules, where Sertoli cells and Leydig cells are distributed. The localizations and intensities of the reactions were constant throughout the maturation of the testis. Within ovarian tissue, the theca cell layers of follicles showed strong reactions of Dig-labeled antisense mRNA probes hybridizing against inhibin alpha and activin beta A and beta B in all samples over the same sampling period. In regressing oocytes, a positive reaction was observed in the granular cell layer of the follicles.     

Up-regulation of the levels of androgen receptor and its mRNA by androgens in smooth-muscle cells from rat penis

Smooth-muscle cells cultured from the penis of sexually immature (I-PSMC) and adult (A-PSMC) rats express similar high levels of the androgen receptor (AR) mRNA. This contrasts with the marked in vivo decline of both AR mRNA and androgen binding in the penile smooth muscle of adult rats, which appears to be responsible for the cessation of androgen-dependent penile growth upon sexual maturation. PSMC is therefore a good model to study down-regulators of AR expression as a function of cell proliferation in the smooth muscle of androgen-reputative sponsive vascular tissue. In order to determine whether AR protein levels in PSMC correlate with AR mRNA levels, the immunocytochemical detection of ARs and their androgen binding capacity were compared between I- and A-PSMC. The number of ARs and their protein half-lives suggested similar levels of translation of the AR mRNA in both cell lines. The effect of the synthetic analog methyltrienolone (R-1881) on androgen binding was studied in contact-inhibited androgen-deprived PSMC. In contrast to the postulated role of androgens as down-regulators of AR expression in rat penis, ARs were up-regulated in A-PSMC by R-1881. Contact inhibition of A-PSMC combined with serum depletion and androgen deprivation down-regulated AR mRNA levels, and dihydrotestosterone (DHT) counteracted this effect. These results suggest that the loss in A-PSMC of the age-dependent down-regulation of ARs observed in vivo in adult corpora cavernosa smooth muscle is related to the in vitro resumption of cell proliferation and that DHT acts directly on the penile smooth muscle as a positive modulator of AR levels.     

再生障碍性贫血雄激素受体与T细胞亚群的变化

目的:检测慢性再生障碍性贫血(CAA)患者骨髓单个核细胞(MNC)雄激素受体(AR)以及骨髓中T细胞亚群水平,探讨AR在CAA免疫病理机制中的作用。方法:①免疫细胞化学SP法检测CAA患者骨髓MNC内AR的表达水平;②流式细胞术检测CAA骨髓中T细胞亚群(CD3 CD4 细胞、CD3 CD8 细胞)的含量。结果:①CAA患者骨髓MNC中AR阳性水平[(35．18±8．78)个／200个MNC]显著低于对照组[(48．46±9．82)个／200个MNC];不同性别间AR的含量差异无统计学意义。②CAA患者骨髓中的CD3 CD8 细胞含量为(28．54±7．57)％,显著高于对照组。③CAA患者骨髓中的AR阳性水平与骨髓中的CD3 CD8 细胞呈负相关(r=-0．576,P<0．01);而与CD3 CD4 细胞含量未见明显的直线相关关系。结论:CAA患者骨髓AR的表达减少,从而使雄激素刺激造血的作用减弱。患者AR的表达与CD3 CD8 细胞含量呈明显负相关,表明AR的异常可能在一定程度上参与了CAA发病机制中的细胞免疫。     

Dehydroepiandrosterone administration reverses the inhibitory influence of aging on gonadotrophin-releasing hormone gene expression in the male and female rat brain

Dehydroepiandrosterone (DHEA) has been shown to exert a beneficial influence on some aging-associated deficits in rodents. It is well documented that in the rat, aging is associated with a decline in reproductive functions. In order to evaluate the effect of DHEA on GnRH gene expression in aged animals, we have studied the effect of 2.5-d administration of DHEA to young (50–54 d of age) and aged (18 mo of age) rats of both sexes. In the young males, DHEA induced an 18% reduction in the hybridization signal. In the aged animals, the mRNA levels were 10% lower than those observed in the young rats. DHEA completely restored the mRNA levels when compared to those detected in young male animals. In the young female, DHEA produced a 11% increase in GnRH mRNA, whereas, in the aged animals, hybridization signal was decreased by 28%. DHEA administration to aged females induced a 33% increase in the amount of mRNA, thus completely reversing the influence of aging. These results indicate that the decrease in GnRH gene expression which is likely involved in the loss of reproductive functions in aged rats can be totally reversed by a short term administration of DHEA which restored the GnRH neuronal activity. They also suggest that DHEA might play a role in the prevention and/or improvement of some deficits associated with aging through stimulation of GnRH biosynthesis.     

甲状腺机能减退对仔鼠中枢神经系统Ⅱ型脱碘酶mRNA表达的影响

目的观察甲状腺激素机能减退(甲减)时仔鼠中枢神经系统Ⅱ型脱碘酶mRNA(D2-mRNA)的表达,研究甲状腺激素对脑发育调控的机制。方法怀孕Wistar雌鼠随机分为甲减组和对照组,从怀孕15d开始甲减组每日经胃灌注1%丙基硫氧嘧啶2.5ml,所生鼠即为甲减仔鼠。对照组每日经胃灌注生理盐水2.5ml。分别于出生时、出生后14、21和45d处死仔鼠,利用荧光定量PCR的方法,分析各组动物大脑皮质、小脑、脑干、海马及脊髓中D2的表达。结果甲减仔鼠大脑、脑干及脊髓中D2mRNA在出生时及出生后14d时表达量高于对照组,在21d和45d时与对照组无显著性差异;在小脑和海马中D2mRNA的表达量在出生时及出生后14、21d时都高于对照组,只有在45d时与对照组接近。结论甲减时仔鼠中枢神经系统D2表达增加,通过调节甲状腺激素水平对其生长发育起着重要作用。     

Human epidermal growth factor receptor 2 expression in mixed gastric carcinoma

AIM: To investigate human epidermal growth factor receptor 2 (HER2) amplification and protein expression in mixed gastric carcinoma.METHODS: Fluorescence in situ hybridization and immunohistochemistry were used to detect HER2 amplification and protein expression in 277 cases of mixed gastric carcinoma. Protein staining intensity was rate as 1+, 2+, or 3+.RESULTS: Of the 277 cases, 114 (41.2%) expressed HER2 protein. HER2 3+ staining was observed in 28/277 (10.1%) cases, 2+ in 37/277 (13.4%) cases, and 1+ in 49/277 (17.7%) cases. A HER2 amplification rate of 17% was detected, of which 25/28 (89.3%) were observed in the HER2 3+ staining group, 17/37 (45.9%) in 2+, and 5/49 (10.2%) in 1+. Of the 47 patients with HER2 amplification who received chemotherapy plus trastuzumab, 22 demonstrated median progression-free and overall survivals of 9.1 mo and 16.7 mo, respectively, which were significantly better than those achieved with chemotherapy alone (5.6 mo and 12.1 mo, respectively) in 19 previously treated patients (Ps < 0.05).CONCLUSION: HER2 detection in mixed gastric carcinoma displays high heterogeneity. Relatively quantitative parameters are needed for assessing the level of HER2 amplification and protein expression.     

小胶质细胞Toll样受体4信号转导通路与中枢神经系统损伤

中枢神经系统损伤机制复杂,小胶质细胞参与了多种中枢神经系统疾病和损伤过程.Toll样受体4(Toll-like receptor 4,TLR4)可介导小胶质细胞的活化和炎性细胞因子的表达,是小胶质细胞发挥功能的重要受体蛋白之一.文章简要介绍了小胶质细胞TLR4信号通路在中枢神经系统损伤中的作用.