The adenoviral E1A protein relieves gene repression by receptors in v/vo displaces corepressors and unliganded thyroid hormone

The human adenovirus type 5 early region 1A （E1A） is one of two oncogenes present in the adenovirus genome and functions by interfering with the activities of cellular regulatory proteins. The E1A gene is alternatively spliced to yield five products. Earlier studies have revealed that E1A can regulate the function of thyroid hormone （T3） receptors （TRs）. However, analysis in yeast compared with transfection studies in mammalian cell cultures yields surprisingly different effects. Here, we have examined the effect of E1A on TR function by using the frog oocyte in vivo system, where the effects of E1A can be studied in the context of chromatin. We demonstrate that different isoforms of E1A have distinct effects on TR function. The two longest forms inhibit both the repression by unliganded TR and activation by T3-bound TR. We further show that E1A binds to unliganded TR to displace the endogenous corepressor nuclear receptor corepressor, thus relieving the repression by unliganded TR. On the other hand, in the presence of T3, E1A inhibits gene activation by T3-bound TR indirectly, through a mechanism that requires its binding domain for the general coactivator p300. Taken together, our results thus indicate that E1A affects TR function through distinct mechanisms that are dependent upon the presence or absence of T3.

Thyroid hormones and thyroid hormone receptors: Effects of thyromimetics on reverse cholesterol transport

Reverse cholesterol transport (RCT) is a complex process which transfers cholesterol from peripheral cells to the liver for subsequent elimination from the body via feces. Thyroid hormones (THs) affect growth, develop- ment, and metabolism in almost all tissues. THs exert their actions by binding to thyroid hormone receptors (TRs). There are two major subtypes of TRs, TRα and TRβ, and several isoforms (e.g. TRα1, TRα2, TRβ1, and TRβ2). Activation of TRα1 affects heart rate, whereas activation of TRβ1 has positive effects on lipid and lipoprotein metabolism. Consequently, particular interest has been focused on the development of thyromimetic compounds targeting TRβ1, not only because of their ability to lower plasma cholesterol but also due their ability to stimulate RCT, at least in pre-clinical models. In this review we focus on THs, TRs, and on the effects of TRβ1-modulating thyromimetics on RCT in various animal models and in humans.

Involvement of chromatin and histone acetylation in the regulation of HIV-LTR by thyroid hormone receptor

The HIV-1 LTR controls the expression of HIV-1 viral genes and thus is critical for viral propagation and pathology. Numerous host factors have been shown to participate in the regulation of the LTR promoter. Among them is the thyroid hormone (T3) receptor (TR). TR has been shown to bind to the critical region of the promoter that contain the NFbB and Sp1 binding sites. Interestingly, earlier transient transfection studies in tissue culture cells have yielded contradicting conclusions on the role of TR in LTR regulation, likely due to the use of different cell types and/or lack of proper chromatin organization. Here, using the frog oocyte as a model system that allows replication-coupled chromatin assembly, mimicking that in somatic cells, we demonstrate that unliganded heterodimers of TR and RXR (9-cis retinoic acid receptor) repress LTR while the addition of T3 relieves the repression and further activates the promoter. More importantly, we show that chromatin and unliganded TR/RXR synergize to repress the promoter in a histone deacetylase-dependent manner.

The roles of thyroid hormone receptor and T3 in metamorphosis of Haliotis diversicolor

Thyroid hormone is a kind of important hormone which regulates metamorphosis. Its role is well described in amphibian metamorphosis. Thyroid hormones (T3 and T4) have also been demonstrated to play a role in metamorphosis of marine invertebrates. However, the mechanism of thyroid hormone in metamorphosis of marine invertebrates remains unknown. A homolog of vertebrate thyroid hormone receptor (TR) was cloned and identified in abalone Haliotis diversicolor and was named HdTR . The mRNA expressions of HdTR , thyroid peroxidase ( TPO ), thyroid peroxidase 1 ( TPO1 ), idothyronine deiodinase Ⅲ( IDⅢ) and integrin alpha-V ( ITGAV ) had significant diff erence in metamorphosis of H . diversicolor . Metamorphosis rate and mortality rate were significantly diff erent in HdTR RNAi experiment and T3 inducing experiment. In RNAi experiment, ITGAV and CCND1 (cyclin D1) expression of dsRNA HdTR exposing group were significantly lower than those of blank control and negative control. But CTNNB (catenin beta) expression of dsRNA HdTR exposing group was higher than that those of blank control and negative control. ERK (extracellular signal regulated kinases) and PI3K (phosphoinositide-3-kinase) had no significant diff erence in RNAi experiment. Moreover, ITGAV of 1 μmol/L T3 group was significantly lower than that of 0 μmol/L T3 group, PI3K expression of 10 μmol/L T3 group was higher than that of 0 μmol/L T3 group, and the other genes expression had no significant diff erence in T3 inducing experiment. The data of genes expression suggested that CCND1 might be an eff ector gene of TR genomic action, while CTNNB might be regulated by unliganded TR. CCND1 and CTNNB may be involved in cell proliferation of metamorphosis. T3 might regulate the expression level of PI3K via nongenomic way. These results shed light on the mechanism of thyroid hormone in abalone metamorphosis.

Molecular Characterization of Thyroid Hormone Receptors (TRs) and their Responsiveness to T3 in Microhylafissipes

To explore and enrich the molecular mechanisms of thyroid hormone receptors （TRs） in the metamorphosis of amphibians, the cDNA sequences of TRa and TRβ in Microhyla fissipes were cloned and characterized. TRa was 1 706 bp in length with an open reading frame （ORF） of 1 257 bp encoding a predicted protein of 418 amino acids and TRβ was 1 422 bp with an ORF of 1 122 bp encoding a predicted protein of 373 amino acids. Their protein sequences contained 4 conserved domains of the nuclear receptor superfamily with two highly conserved cysteine-rich zinc fingers in the DNA-binding domain, whereas TRβ was 42 amino acids shorter in its A/B domain than TRot. Highly-conserved sequences and structures indicated their conserved functions during metamorphosis. TRa expression reached peak at 12 h and then decreased from 12 h to 48 h. While dramatically up-regulated TRβ was observed after exposure of T3 within 24 h, and it was down-regulated from 24 h to 48 h. The expression pattern of TRβ is similar to that in the natural metamorphosis. Furthermore, tadpoles treated 24 h also resembled the climax of metamorphosis tadpoles and TRβ expression had higher responsiveness than TRa to T3 in M. fissipes. These results suggest M. fissipes may serve as the model to assay environmental compounds on TH signaling disruption.

Cloning and Expression Level Analysis of Melanocyte-stimulating Hormone Receptor 1 Gene(MC1R) in Alpacas with Different Coat Color

Specific primers for the MC1R gene of alpacas(GenBank EU1358800) were designed to amplify the cDNA sequence using RT-PCR to seek variation in the sequence and explore the relationship between the expression level of MC1R gene and alpaca coat color.The MC1R gene from white alpaca was cloned successfully and sequence analysis verified that the MC1R gene,encoding 317 amino acids,was 1081 bp in length.Compared with the existing sequence in GenBank,sequence identity was 99.9%and 7 mutations were found.Primers,designed from the sequence obtained,were used to assess the relative expression of MC1R in alpacas of different coat color using QRT-PCR and SPSS 13.0 software.Relative expression of MC1R in the skin of brown alpacas was 4.32 times higher than that in white alpacas after normalization with GAPDH(P【0.01),indicating that MC1R expression may be related to coat color of alpacas.

Distinct expression profiles of transcriptional coactivators for thyroid hormone receptors during Xenopus laevis metamorphosis

The biological effects of thyroid hormone (T3) are mediated by the thyroid hormone receptor (TR). Amphibian metamorphosis is one of the most dramatic processes that are dependent on T3. T3 regulates a series of orchestrated developmental changes, which ultimately result in the conversion of an aquatic herbivorous tadpole to a terrestrial carnivorous frog. T3 is presumed to bind to TRs, which in turn recruit coactivators, leading to gene activation. The best-studied coactivators belong to the p160 or SRC family. Members of this family include SRC1/NCoA-1, SRC2/TIF2/GRIP1, and SRC3/pCIP/ACTR/AIB-1/RAC-3/TRAM-1. These SRCs interact directly with liganded TR and function as adapter molecules to recruit other coactivators such as p300/CBP. Here, we studied the expression patterns of these coactivators during various stages of development. Amongst the coactivators cloned in Xenopus laevis, SRC3 was found to be dramatically upregulated during natural and T3-induced metamorphosis, and SRC2 and p300 are expressed throughout postembryonic development with little change in their expression levels. These results support the view that these coactivators participate in gene regulation by TR during metamorphosis.

A retrospective cohort analysis of the relationship between thyroid hormone level and herpes simplex virus-1 activation

A number of physiological factors have been suggested to participate in the Herpes Simplex Virus Type-1 (HSV-1) reactivation. Of particular interest is the effect of hormonal aberration on gene expression and activation. Thyroid hormone (TH) was shown to play a role in HSV-1 gene expression and replication in cell culture and animal models. We hypothesize that TH participates in the control of HSV latency and reactivation in humans by regulating viral gene expression and replication. Prior to implementing a full-scale population-based inquiry into this hypothesis, a pilot study using a pharmacy claims data base and a case-controlled, retrospective cohort preliminary investigation was conducted to develop further the hypothetical link between TH and HSV-1 reactivation. Using prescriptions for treating thyroid disorders and HSV-1 infections as proxies for biologic functions, we queried a prescription data base to construct two patient cohorts: Cohort 1 was comprised of patients receiving prescription drugs for thyroid disorders over a three-month period, and Cohort 2 was composed of patients not receiving thyroid medications during this period. HSV-1 medications were recorded for each cohort and the difference in the frequency of HSV-1 prescription drug utilization was examined for statistical significance. Using a 2 × 2 contingency table, a chi-square of 10.12 was calculated that was significant at p = 0.0015, confirming that a significant difference was found in HSV-1 utilization between these two cohorts, suggesting that patients who receive thyroid drugs have a greater chance of receiving antiviral drugs for HSV-1 infection/reactivation. Since this pilot study has inherent limitations in the data set, this finding is descriptive, not explanatory, and further research involving more detailed patient records in a larger patient population will be implemented to explore the relationship more robustly.

Involvement of Met receptor pathway in aggressive behavior of colorectal cancer cells induced by parathyroid hormone-related peptide

BACKGROUND Parathyroid hormone-related peptide(PTHrP)plays a key role in the development and progression of many tumors.We found that in colorectal cancer(CRC)HCT116 cells,the binding of PTHrP to its receptor PTHR type 1(PTHR1)activates events associated with an aggressive phenotype.In HCT116 cell xenografts,PTHrP modulates the expression of molecular markers linked to tumor progression.Empirical evidence suggests that the Met receptor is involved in the development and evolution of CRC.Based on these data,we hypothesized that the signaling pathway trigged by PTHrP could be involved in the transactivation of Met and consequently in the aggressive behavior of CRC cells.AIM To elucidate the relationship among PTHR1,PTHrP,and Met in CRC models.METHODS For in vitro assays,HCT116 and Caco-2 cells derived from human CRC were incubated in the absence or presence of PTHrP(1-34)(10-8 M).Where indicated,cells were pre-incubated with specific kinase inhibitors or dimethylsulfoxide,the vehicle of the inhibitors.The protein levels were evaluated by Western blot technique.Real-time polymerase chain reaction(RT-qPCR)was carried out to determine the changes in gene expression.Wound healing assay and morpho logical monitoring were performed to evaluate cell migration and changes related to the epithelialmesenchymal transition(EMT),respectively.The number of viable HCT116 cells was counted by trypan blue dye exclusion test to evaluate the effects of irinotecan(CPT-11),oxaliplatin(OXA),or doxorubicin(DOXO)with or without PTHrP.For in vivo tests,HCT116 cell xenografts on 6-wk-old male N:NIH(S)_nu mice received daily intratumoral injections of PTHrP(40μg/kg)in 100μL phosphate-buffered saline(PBS)or the vehicle(PBS)as a control during 20 d.Humanitarian slaughter was carried out and the tumors were removed,weighed,and fixed in a 4%formaldehyde solution for subsequent treatment by immunoassays.To evaluate the expression of molecular markers in human tumor samples,we studied 23 specimens obtained from CRC patients which were treated at the Hospital Interzonal de Graves y Agudos Dr.JoséPenna(Bahía Blanca,Buenos Aires,Argentina)and the Hospital Provincial de Neuquén(Neuquén,Neuquén,Argentina)from January 1990 to December 2007.Seven cases with normal colorectal tissues were assigned to the control group.Tumor tissue samples and clinical histories of patients were analyzed.Paraffin-embedded blocks from primary tumors were reviewed by hematoxylin-eosin staining technique;subsequently,representative histological samples were selected from each patient.From each paraffin block,tumor sections were stained for immunohistochemical detection.The statistical significance of differences was analyzed using proper statistical analysis.The results were considered statistically significant at P<0.05.RESULTS By Western blot analysis and using total Met antibody,we found that PTHrP regulated Met expression in HCT116 cells but not in Caco-2 cells.In HCT116 cells,Met protein levels increased at 30 min(P<0.01)and at 20 h(P<0.01)whereas the levels diminished at 3 min(P<0.05),10 min(P<0.01),and 1 h to 5 h(P<0.01)of PTHrP treatment.Using an active Met antibody,we found that where the protein levels of total Met decreased(3 min,10 min,and 60 min of PTHrP exposure),the status of phosphorylated/activated Met increased(P<0.01)at the same time,suggesting that Met undergoes proteasomal degradation after its phosphorylation/activation by PTHrP.The increment of its protein level after these decreases(at 30 min and 20 h)suggests a modulation of Met expression by PTHrP in order to improve Met levels and this idea is supported by our observation that the cytokine increased Met mRNA levels at least at 15 min in HCT116 cells as revealed by RT-qPCR analysis(P<0.05).We then proceeded to evaluate the signaling pathways that mediate the phosphorylation/activation of Met induced by PTHrP in HCT116 cells.By Western blot technique,we observed that PP1,a specific inhibitor of the activation of the protooncogene protein tyrosine kinase Src,blocked the effect of PTHrP on Met phosphorylation(P<0.05).Furthermore,the selective inhibition of the ERK 1/2 mitogen-activated protein kinase(ERK 1/2 MAPK)using PD98059 and the p38 MAPK using SB203580 diminished the effect of PTHrP on Met phosphorylation/activation(P<0.05).Using SU11274,the specific inhibitor of Met activation,and trypan blue dye exclusion test,Western blot,wound healing assay,and morphological analysis with a microscope,we observed the reversal of cell events induced by PTHrP such as cell proliferation(P<0.05),migration(P<0.05),and the EMT program(P<0.01)in HCT116 cells.Also,PTHrP favored the chemoresistance to CPT-11(P<0.001),OXA(P<0.01),and DOXO(P<0.01)through the Met pathway.Taken together,these findings suggest that Met activated by PTHrP participates in events associated with the aggressive phenotype of CRC cells.By immunohistochemical analysis,we found that PTHrP in HCT116 cell xenografts enhanced the protein expression of Met(0.190±0.014)compared to tumors from control mice(0.110±0.012;P<0.05)and of its own receptor(2.27±0.20)compared to tumors from control mice(1.98±0.14;P<0.01).Finally,assuming that the changes in the expression of PTHrP and its receptor are directly correlated,we investigated the expression of both Met and PTHR1 in biopsies of CRC patients by immunohistochemical analysis.Comparing histologically differentiated tumors with respect to those less differentiated,we found that the labeling intensity for Met and PTHR1 increased and diminished in a gradual manner,respectively(P<0.05).CONCLUSION PTHrP acts through the Met pathway in CRC cells and regulates Met expression in a CRC animal model.More basic and clinical studies are needed to further evaluate the PTHrP/Met relationship.

食管癌术后肾上腺危象1例并文献复习

目的:探讨肾上腺危象(AC)的临床特征及诊疗要点,减少临床工作中的漏诊、误诊、误治。方法:回顾性分析1例食管癌术后合并AC的临床资料,总结AC的临床诊治经过。结果:患者为49岁男性,因食管癌术后3周出现发热入院,存在吻合口瘘,给予多种抗菌药物长时间抗感染治疗效果不佳,即使瘘口愈合后仍间断高热、血压下降。患者偶用激素退热治疗后效果较好,但减量停用后患者逐渐乏力、卧床。查增强计算机断层扫描(CT)未见肿瘤复发,皮质醇、促肾上腺皮质激素(ACTH)明显偏低,结合术前曾应用程序性死亡受体1(PD-1)抑制剂,明确诊断为免疫治疗相关垂体炎,进而导致了AC,补充醋酸泼尼松片后好转出院。结论:AC是一种危急的内科急症,临床表现缺乏特异性,极容易漏诊、误诊、误治,临床医生应加强对本病的认识,从而达到早期诊断并能及时给予糖皮质激素治疗的目的。

Periostin、Notch1、维生素D与自身免疫性甲状腺炎淋巴细胞浸润程度、Treg/Th17的相关性研究

目的探讨骨外膜素(Periostin)、Notch跨膜受体-1(Notch1)m RNA、维生素D(VitD)与自身免疫性甲状腺炎(AIT)淋巴细胞浸润程度、调节性T细胞/辅助性T细胞17(Treg/Th17)的相关性。方法选取2021年7月至2023年12月郑州大学第一附属医院收治的92例AIT患者纳入AIT组,另选取同期50例无甲状腺疾病的健康人群纳入对照组。比较两组受检者的淋巴细胞浸润程度及抗体水平,采用Spearman、Pearson相关系数分析淋巴细胞浸润程度、Treg/Th17与甲状腺功能、抗体水平的相关性,比较两组受检者的Periostin、Notch1 m RNA、VitD及Treg/Th17,采用Pearson相关系数分析Periostin、Notch1 mRNA、VitD与淋巴细胞浸润程度及Treg/Th17的相关性。结果AIT组患者的CD3^(+)、CD3^(+)CD4^(+)、CD4^(+)CD25^(+)CD127^(-)、TgAb、TPOAb、TRAb水平及甲亢/亚临床甲亢、甲减/亚临床甲减患者占比明显高于对照组,差异均有统计学意义(P<0.05);Pearson相关系数分析结果显示,CD3^(+)(r=0.579、0.602、0.563)、CD3^(+)CD4^(+)(r=0.612、0.637、0.606)、CD~4+CD25^(+)CD127^(-)(r=0.655、0.643、0.687)与TgAb、TPOAb、TRAb呈正相关(P<0.05);AIT组患者的Periostin、Notch1 m RNA分别为(4.27±1.40)μg/L、1.73±0.56,明显高于对照组的(2.86±0.49)μg/L、1.02±0.14,VitD、Treg/Th17分别为(17.82±5.09)ng/mL、2.82±0.97,明显低于对照组的(22.30±3.76)ng/mL、12.36±2.03,差异均有统计学意义(P<0.05);Pearson相关系数分析结果显示,Periostin(r=0.792、0.811、0.737)、Notch1 mRNA(r=0.812、0.775、0.792)与CD3^(+)、CD3^(+)CD4^(+)、CD4^(+)CD25+CD127-呈正相关(P<0.05),VitD(r=-0.687、-0.753、-0.799)与之呈负相关(P<0.05),且Periostin(r=-0.823)、Notch1 m RNA(r=-0.772)与Treg/Th17呈负相关(P<0.05),VitD(r=0.745)与之呈正相关(P<0.05)。结论Periostin、Notch1 mRNA在AIT患者血清中表达上调,VitD表达下调,各指标与AIT淋巴细胞浸润程度及Treg/Th17均具有一定相关性,可为临床判断病情提供参考,并对后续临床治疗具有一定指导价值。

^(131)I治疗对分化型甲状腺癌患者术后血清iPTH、IGF-1水平的影响

目的探讨^(131)I治疗对分化型甲状腺癌患者术后血清全段甲状旁腺激素(iPTH)、胰岛素样生长因子1(IGF-1)水平的影响。方法回顾性分析河南科技大学第一附属医院2020年1月至2022年9月收治的73例分化型甲状腺癌患者,均接受甲状腺全切除并于术后2个月采用^(131)I治疗,随访1个月根据治疗情况将患者分为有效组(51例)和无效组(22例)。比较两组患者治疗前及治疗7 d iPTH和IGF-1水平,以及有效组治疗后各时间点血清iPTH、IGF-1水平。结果两组患者治疗后7 d血清iPTH、IGF-1水平均低于治疗前,且有效组低于无效组(P<0.05);有效组治疗后不同时间点血清iPTH、IGF-1水平差异有统计学意义(P<0.05)。结论分化型甲状腺癌患者^(131)I治疗后血清iPTH、IGF-1水平变化可用于判断甲状旁腺功能恢复情况,血清iPTH还可预示术后低钙血症的发生。

Stimulating effect of thyroid hormones in peripheral nerve regeneration:research history and future direction toward clinical therapy

Injury to peripheral nerves is often observed in the clinic and severe injuries may cause loss of motor and sensory functions.Despite extensive investigation,testing various surgical repair techniques and neurotrophic molecules,at present,a satisfactory method to ensuring successful recovery does not exist.For successful molecular therapy in nerve regeneration,it is essential to improve the intrinsic ability of neurons to survive and to increase the speed of axonal outgrowth.Also to induce Schwann cell phenotypical changes to prepare the local environment favorable for axonal regeneration and myelination.Therefore,any molecule that regulates gene expression of both neurons and Schwann cells could play a crucial role in peripheral nerve regeneration.Clinical and experimental studies have reported that thyroid hormones are essential for the normal development and function of the nervous system,so they could be candidates for nervous system regeneration.This review provides an overview of studies devoted to testing the effect of thyroid hormones on peripheral nerve regeneration.Also it emphasizes the importance of combining biodegradable tubes with local administration of triiodothyronine for future clinical therapy of human severe injured nerves.We highlight that the local and single administration of triiodothyronine within biodegradable nerve guide improves significantly the regeneration of severed peripheral nerves,and accelerates functional recovering.This technique provides a serious step towards future clinical application of triiodothyronine in human severe injured nerves.The possible regulatory mechanism by which triiodothyronine stimulates peripheral nerve regeneration is a rapid action on both axotomized neurons and Schwann cells.

Fhyroid hormone controls the gene expression of HSV-1 .AT and ICPO in neuronal cells

Various factors/pathways including hormonal regulation have been suggested to control herpes simplex virus type 1 （HSV-1） latency and reactivation. Our computer analysis identified a DNA repeat containing thyroid hormoneresponsive elements （TRE） in the regulatory region of HSV-1 latency-associated transcript （LAT）. Thyroid hormone （triiodothyronine, T3） functions via its receptor TR （thyroid hormone receptor）, a transcription factor. Present study investigated the roles of TR and T3 in HSV-1 gene expression using cultured neuoroblastoma cell lines. We demonstrated that liganded TR activated LAT transcription, but repressed infected cell protein no. 0 （ICP0） transcription in the presence of LAT TRE. Chromatin immunoprecipitation （CHIP） assays showed that TRs were recruited to LAT TREs independently of T3 and hyperacetylated H4 was associated with the LAT promoter that was transcriptionally active. In addition, ChIP results showed that the chromatin insulator protein CCCTC-binding factor was enriched at the LAT TREs in the presence of TR and T3. In addition, the BRG1 chromatin remodeling complex is found to participate in the T3/TR-mediated LAT activation since overexpression of BRG1 enhanced the LAT transcription and the dominant-negative mutant K785R abolished the activation. This is the first report revealing that TR elicits epigenetic regulation on HSV-1 ICP0 expression in neuronal cells and could have a role in the complex processes of HSV-1 latency/reactivation.

Osteoporotic fracture and parathyroid hormone

Osteoporosis and age-related bone loss is associated with changes in bone remodeling characterized by decreased bone formation relative to bone resorption,resulting in bone fragility and increased risk of fractures.Stimulating the function of bone-forming osteoblasts,is the preferred pharmacological intervention for osteoporosis.Recombinant parathyroid hormone(PTH),PTH(1-34),is an anabolic agent with proven benefits to bone strength and has been characterized as a potential therapy for skeletal repair.In spite of PTH’s clinical use,safety is a major consideration for long-term treatment.Studies have demonstrated that intermittent PTH treatment enhances and accelerates the skeletal repair process via a number of mechanisms.Recent research into the molecular mechanism of PTH action on bone tissue has led to the development of PTH analogs to control osteoporotic fractures.This review summarizes a number of advances made in the field of PTH and bone fracture to combat these injuries in humans and in animal models.The ultimate goal of providing an alternative to PTH,currently the sole anabolic therapy in clinical use,to promote bone formation and improve bone strength in the aging population is yet to be achieved.

Amphibian metamorphosis as a model for studying the developmental actions of thyroid hormone

The thyroid hormones L-thyroxine and triiodo-L-thyronine have profound effects on postembryonic development of most vertebrates. Analysis of their action in mammals is vitiated by the exposure of the developing foetus to a number of maternal factors which do not allow one to specifically define the role of thyroid hormone (TH)or that of other hormones and factors that modulate its action. Amphibian metamorphosis is obligatorily dependent on TH which can initiate all the diverse physiological manifestations of this postembryonic developmental process(morphogenesis, cell death, re-structuring, etc.) in free-living embryos and larvae of most anurans. This article will first describe the salient features of metamorphosis and its control by TH and other hormones. Emphasis will be laid on the key role played by TH receptor (TR), in particular the phenomenon of TR gene autoinduction, in initiating the developmental action of TH. Finally, it will be argued that the findings on the control of amphibian metamorphosis enhance our understanding of the regulation of postembryonic development by TH in other vertebrate species.

Effect of sericin on diabetic hippocampal growth hormone/insulin-like growth factor 1 axis

Previous studies have shown that sericin extracted from silk cocoon significantly reduces blood glucose levels and protects the nervous system against diabetes mellitus. In this study, a rat type 2 diabetes mellitus model was established by intraperitoneal injection of 25 mg/kg streptozotocin for 3 successive days, following which the rats were treated with sericin for 35 days. After treatment, the blood glucose levels of the diabetic rats decreased significantly, the growth hormone level in serum and its expression in the hippocampus decreased significantly, while the insulin-like growth factor-1 level in serum and insulin-like growth factor-1 and growth hormone receptor expression in the hippocampus increased significantly. The experimental findings indicate that sericin improves disorders of the growth hormone/insulin-like growth factor 1 axis to alleviate hippocampal damage in diabetic rats.

甲状腺激素受体相互作用物11基因变异所致软骨生成不全IA型家系遗传学分析

软骨生成不全IA型是一种罕见的致死性疾病,以常染色体隐性方式遗传,该疾病的发生与人14号染色体上甲状腺激素受体相互作用物11(TRIP11)基因变异有关。本研究采集了1例超声检查疑似致命性骨骼发育不良胎儿的流产皮肤组织及其父母的静脉血,通过提取基因组DNA,应用全外显子组测序技术对胎儿组织及其父母进行平行测序,对疑似致病变异用Sanger测序进行验证;并对以往报道基因检测结果进行文献复习,结合文献复习探讨该病的临床特点。结果发现了胎儿TRIP11检测到复合杂合变异c.790C>T(p.R264*)/c.589-2A>G,两位点分别来自父亲和母亲,符合常染色体隐性遗传。本研究报道的TRIP11基因复合杂合变异尚未见报道,拓宽了软骨生成不全1A型的基因变异谱,为该家庭的遗传咨询及产前诊断提供了重要的分子基础。

Thyroid hormone regulation of apoptotic tissue remodeling during anuran metamorphosis

Anuran metamorphosis involves systematic transformations of individual organs in a thyroid hormone (TH)-dependent manner. Morphological and cellular studies have shown that the removal of larval or- gans/tissues such the tail and the tadpole intestinal epithelium is through programmed cell death or apop- tosis. Recent molecular investigations suggest that TH regulates metamorphosis by regulating target gene expression through thyroid hormone receptors (TRs), which are DNA-binding transcription factors. Cloning and characterization of TH response genes show that diverse groups of early response genes are induced by TH. The products of these TH response genes are believed to directly or indirectly affect the expression and/or functions of cell death genes, which are conserved at both sequence and function levels in different animal species. A major challenge for future research lies at determining the signaling pathways leading to the activation of apoptotic processes and whether different death genes are involved in the regulation of apoptosis in different tissues/organs to effect tissue-specific transformations.

Inhibition effects of parathyroid hormone on human medullary thyroid carcinoma cells

Objective： The purpose of the study was to investigate the effects of parathyroid hormone and parathyroid hormone receptor monoclonal antibody on in vitro growth and proliferation of human medullary thyroid carcinoma cell lines. Methods： The medullary thyroid carcinoma cell line was cultured in vitro, with parathyroid hormone and parathyroid hormone receptor monoclonal antibody treatment intervention, the growth of the cells was observed under an inverted contrast micro scope, the MTT assay was used to detect the cell growth inhibition rate. Results： Under the inverted contrast microscope, the cells changed significantly, the parathyroid hormone and parathyroid hormone receptor monoclonal antibodies can effectively inhibit the proliferation of medullary thyroid cancer cells in a time and dose dependent. When parathyroid hormone concentra tion reached a concentration of 2.0 IJmol/L, the parathyroid hormone receptor monoclonal antibody reached a concentration of 1.0 μmol/L, the cell growth was most significantly inhibited （P 〈 0.05）. Conclusion： Parathyroid hormone and parathyroid hormone receptor monoclonal antibody were able to inhibit the proliferation of medullary thyroid carcinoma cells and signifi cantly reduce the proliferation index.