N-acetylcysteine and zinc sulphate abate di-2-ethylhexyl phthalate-mediated reproductive dysfunction in rats:Focus on oxidative and sex hormone receptors mechanisms

Objective:To investigate the potential of N-acetylcysteine(NAC)and zinc sulphate(ZnSO_(4))in mitigating reproductive dysfunction caused by di-2-ethylhexyl phthalate(DEHP)in rats and to understand the underlying mechanisms,specifically oxidative stress and sex hormone receptor activity.Methods:Thirty-five male Wistar rats were randomly divided into five equal groups(n=7 per group).Group 1 was administered 0.5 mL of distilled water and served as the control group.Group 2 was given only DEHP(750 mg/kg/day),while group 3,4 and 5 were given DEHP(750 mg/kg/day)plus NAC(100 mg/kg/day),DEHP(750 mg/kg/day)plus ZnSO_(4)(0.5 mg/kg/day),and DEHP(750 mg/kg/day)plus NAC(100 mg/kg/day)as well as ZnSO_(4)(0.5 mg/kg/day),respectively.All treatments lasted for 21 days.Samples were obtained after the rats were sacrificed,and hormones levels in the serum and markers of oxidative stress in the testicles were analyzed using the enzyme-linked immunosorbent assay.The amount of androgen receptors in the testicles was determined by immunohistochemistry,and the susceptibility of testosterone and DEHP to bind to androgen receptor and 5α-reductase was determined by molecular docking studies.Results:DEHP decreased reproductive hormones,testicular antioxidant enzymes,increased malondialdehyde levels,and negatively impacted histology of the pituitary and testes.NAC or ZnSO_(4) treatment showed a marked improvement in testicular antioxidant status and hormone levels,as well as a positive effect on the histology of the pituitary and testes.The combination of both treatments appeared to be more effective.The affinity of DEHP to bind to androgen receptors may lead to disruption of androgen receptor signaling,which can further result in dysfunction of hormones related to androgen.However,NAC is more likely to form stronger binding interactions with follicle stimulating hormone and luteinizing hormone receptors,as well as gonadotropin-releasing hormone receptors,when compared to DEHP.Conclusions:The possibility that NAC and ZnSO_(4) could downregulate DEHP-induced sex hormone changes is suggested by their potential to reduce toxicity.

Association between sensitivity to thyroid hormones and non-highdensity lipoprotein cholesterol levels in patients with type 2 diabetes mellitus

BACKGROUND Dyslipidemia and type 2 diabetes mellitus(T2DM)are chronic conditions with substantial public health implications.Effective management of lipid metabolism in patients with T2DM is critical.However,there has been insufficient attention given to the relationship between thyroid hormone sensitivity and dyslipidemia in the T2DM population,particularly concerning non-high-density lipoprotein cholesterol(non-HDL-C).AIM To clarify the association between thyroid hormone sensitivity and dyslipidemia in patients with T2DM.METHODS In this cross-sectional study,thyroid hormone sensitivity indices,the thyroid feedback quantile-based index(TFQI),the thyroid-stimulating hormone index(TSHI),the thyrotrophic T4 resistance index(TT4RI),and the free triiodothyronine(FT3)/free thyroxine(FT4)ratio were calculated.Logistic regression analysis was performed to determine the associations between those composite indices and non-HDL-C levels.Random forest variable importance and Shapley Additive Explanations(SHAP)summary plots were used to identify the strength and direction of the association between hyper-non-HDL-C and its major predictor.RESULTS Among the 994 participants,389(39.13%)had high non-HDL-C levels.Logistic regression analysis revealed that the risk of hyper-non-HDL-C was positively correlated with the TFQI(OR:1.584;95%CI:1.088-2.304;P=0.016),TSHI(OR:1.238;95%CI:1.034-1.482;P=0.02),and TT4RI(OR:1.075;95%CI:1.006-1.149;P=0.032)but was not significantly correlated with the FT3/FT4 ratio.The relationships between composite indices of the thyroid system and non-HDL-C levels differed according to sex.An increased risk of hyper-non-HDL-C was associated with elevated TSHI levels in men(OR:1.331;95%CI:1.003-1.766;P=0.048)but elevated TFQI levels in women(OR:2.337;95%CI:1.4-3.901;P=0.001).Among the analyzed variables,the average SHAP values were highest for TSHI,followed by TT4RI.CONCLUSION Impaired sensitivity to thyroid hormones was associated with high non-HDL-C levels in patients with T2DM.

Effect of TSH Suppression Therapy on Sex Hormone Levels after Thyroid Cancer Surgery

Objective:To analyze the effect of thyroid-stimulating hormone(TSH)suppression therapy on sex hormone levels in patients undergoing postoperative treatment for thyroid cancer.Methods:A total of 40 patients undergoing postoperative thyroid cancer treatment were selected for data analysis.TSH suppression therapy was implemented during the postoperative period.Patients were grouped according to the TSH level:TSH<0.1,0.1≤TSH<0.5,and TSH≥0.5.Results:Among male patients,there were no significant differences in sex hormone levels at different dosing times and TSH levels(P>0.05).For female patients,testosterone levels at different dosing times showed no significant differences under the same circumstances(P>0.05).The comparison of testosterone levels at different TSH levels over 5 years of TSH suppression therapy did not yield significant differences(P>0.05).However,the comparison of testosterone levels within 5 years of TSH suppression therapy yielded significant differences(P<0.05),with the lowest levels observed at 0.1≤TSH<0.5.Conclusion:The use of TSH suppression therapy in postoperative thyroid cancer treatment minimally affects sex hormone levels in male patients.However,it has a significant impact on female patients.Therefore,preoperative sex hormone testing is recommended,and postoperative monitoring should include regular sex hormone testing.

Adipokinetic hormone signaling regulates adult dehydration resistance in the migratory locust

Drought events have become more severe under climate change,and this can pose a major threat to the survival of various organisms.The molecular mechanisms involved in dehydration resistance are not well known.Here,adults of the migratory locust,Locusta migratoria,were subjected to food-mediated dehydration,and adipokinetic hormone(AKH)signaling was found to play a key role in regulating dehydration resistance.Specifically,dehydration shortened the lifespan,increased the body weight loss,and reduced the water loss rate in adult locusts.Global transcriptome profiles revealed variations in tissue-specific gene expression between dehydration-resistant locusts and normal locusts.Importantly,dehydration selection and exposure induced prominent expression of AKH genes in the retrocerebral complex of adult locusts.Furthermore,individual knockdown of AKH1,AKH2,or AKH receptor(AKHR)accelerated water loss and shortened the lifespan of adult locusts under dehydration conditions,and trehalose supplementation ameliorated the negative effects caused by interference with AKH or AKHR.These findings demonstrated that AKH/AKHR signaling-dependent trehalose metabolism plays a crucial role in regulating locust dehydration resistance and thus provide novel insights into the regulatory mechanism underlying drought resistance.

Analysis of the value and safety of thyroid-stimulating hormone in the clinical efficacy of patients with thyroid cancer

BACKGROUND Thyroid cancer(TC)is a common malignant tumor in the endocrine system.In recent years,the incidence and recurrence rates of TC have been raising due to increasing work pressure and irregular lifestyles.Thyroid-stimulating hormone(TSH)is a specific parameter for thyroid function screening.This study aims to explore the clinical value of TSH in regulating the progression of TC,so as to find a breakthrough for the early diagnosis and treatment of TC.AIM To explore the value and safety of TSH in the clinical efficacy of patients with TC.METHODS 75 patients with TC admitted to the Department of Thyroid and Breast Surgery of our hospital from September 2019 to September 2021 were selected as the observation group,and 50 healthy subjects were selected as the control group during the same period.The control group was treated with conventional thyroid replacement therapy,and the observation group was treated with TSH suppression therapy.The soluble interleukin(IL)-2 receptor(sIL-2R),IL-17,IL-35levels,free triiodothyronine(FT3),free tetraiodothyronine(FT4),CD3+,CD4+,CD8+,CD44V6,and tumor supplied group of factor(TSGF)levels were observed in the two groups.The occurrence of adverse reactions was compared between the two groups.RESULTS After treatment with different therapies,the levels of FT3,FT4,CD3+,and CD4+in the observation group and the control group were higher than those before treatment,while the levels of CD8+,CD44V6,and TSGF were lower than those before treatment,and the differences were statistically significant(P<0.05).More importantly,the levels of sIL-2R and IL-17 in the observation group were lower than those in the control group after 4 wk of treatment,while the levels of IL-35 were higher than those in the control group,and the differences were statistically significant(P<0.05).The levels of FT3,FT4,CD3+,and CD4+in the observation group were higher than those in the control group,and the levels of CD8+,CD44V6,and TSGF were lower than those in the control group.There was no significant difference in the overall incidence rate of adverse reactions between the two groups(P>0.05).CONCLUSION TSH suppression therapy can improve the immune function of patients with TC,lower the CD44V6 and TSGF levels,and improve serum FT3 and FT4 levels.It demonstrated excellent clinical efficacy and a good safety profile.

Exploring the relationship between Hashimoto's thyroiditis and male fertility:A meta-analytic and meta-regression perspective on hormonal and seminal factors

Objective:To explore the relationship between Hashimoto's autoimmune hypothyroidism(HT)and male fertility,focusing on hormonal and seminal factors.Methods:A systematic literature search was conducted across databases such as PubMed,Web of Science,EMBASE,Scopus,Cochrane,and Google Scholar,covering studies published from January 2000 to March 2024.Studies investigating the impact of HT on semen quality parameters and reproductive hormones were included.Pooled effect estimates were calculated using standard mean difference(SMD)and 95%confidence intervals(CI).Results:A total of 8 studies with 8965 participants were included.HT significantly affected semen quality and reproductive hormone levels.Specifically,there was a notable decrease in progressive morphology(SMD=-0.78;95%CI:-1.40 to-0.17;P=0.01)and sperm motility(SMD=-1.151;95%CI:-1.876 to-0.425;P=0.002).In addition,there were no significant changes in reproductive hormones,although there were elevated levels of luteinizing hormone(SMD=0.437;95%CI:0.000 to 0.874;P=0.050)and follicle-stimulating hormone(SMD=0.293;95%CI:-0.171 to 0.758;P=0.216),with a slight impact on testosterone levels(SMD=-1.143;95%CI:-2.487 to 0.200;P=0.095).Conclusions:This systematic review and meta-analysis provides robust evidence of the detrimental effects of HT on semen quality and reproductive hormones,underscoring the necessity for thorough evaluation and management of thyroid function in male infertility assessments.

Correlation analysis of serum thyroglobulin,thyroid-stimulating hormone levels,and thyroid-cancer risk in thyroid nodule surgery

BACKGROUND Thyroglobulin(Tg)is one of the markers of thyroid cancer,and its concentration may be elevated in patients with malignant thyroid tumors.Thyroid-stimulating hormone(TSH)is secreted by the pituitary gland,which has a significant impact on thyroid gland function.Excessively high or low TSH levels may be associated with an increased risk of thyroid cancer.Thus,in-depth studies on the association of serum Tg and TSH levels with thyroid cancer risk in patients with thyroid nodules are warranted.This can help determine whether Tg and TSH levels can predict the degree of malignancy of thyroid nodules,which can in turn guide doctors in making accurate diagnoses and treatment decisions.Furthermore,such studies can provide more accurate diagnostic methods for thyroid nodules and help patients become aware of the presence of thyroid cancer as early as possible,thereby improving the success rate of treatment and prognosis.AIM To investigate the association of serum Tg and TSH levels with the risk of thyroid cancer in patients undergoing thyroid nodule surgery.METHODS The clinical data and laboratory examination results of 130 patients who underwent thyroid nodule surgery were retrospectively analyzed.Furthermore,their preoperative serum Tg and TSH levels were recorded.Histopathological examination conducted during follow-up revealed the presence of thyroid cancer.Correlation analysis were used to analyze the association of Tg and TSH levels with the risk of thyroid cancer.RESULTS Of the 130 patients,60 were diagnosed with thyroid cancer.Statistical analysis revealed a significant positive correlation between serum Tg levels and the risk of thyroid cancer(P<0.05).This suggests that high serum Tg levels are associated with an increased risk of thyroid cancer.However,no significant correlation was observed between serum TSH levels and the risk of thyroid cancer(P>0.05).CONCLUSION In patients who underwent thyroid nodule surgery,serum Tg levels exhibited a significant correlation with the risk of thyroid cancer but serum TSH levels did not.These findings suggest that serum Tg can serve as an important biomarker for assessing the risk of thyroid cancer in these patients.

Association of Serum Ferritin Levels and Thyroid Hormones

Thyroid metabolism is orchestrated by the action of various minerals and trace elements including iron, iodine, selenium, and zinc. Iron deficiency, specifically deficiency in serum ferritin levels, is one of the common causes of thyroid dysfunction. Our objective was to evaluate the relationship between serum ferritin levels and circulating thyroid hormones. For this, a retrospective analysis was performed on 16,512 individuals who tested for serum levels of ferritin and thyroid profile at Vibrant America Clinical Laboratories. Subjects were stratified based on the serum levels of ferritin. Age (p −0.03232, p < 0.0001). Analysis of Linear association by Pearson’s correlation exhibited a considerable correlation between varying serum ferritin levels with all tested thyroid hormones. The study concludes that serum ferritin levels were associated with thyroid hormone synthesis and metabolism in individuals with optimal levels of circulating ferritin.

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.

The transcription of iodothyronine deiodinase genes is regulated by thyroid hormone receptor in the Pacific oyster Crassostrea gigas

Thyroid hormones (THs) are indispensable for each phyla in Chordata, while their functions in the non-chordate invertebrates are indistinct. Studies on the TH system in non-chordate invertebrates are important for understanding the evolution of TH system and may be applied in aquaculture or biofouling control at the same time. Iodothyronine deiodinases are keys to studying the TH system, as they are critical enzymes in maintaining TH homeostasis by catalyzing the initiation and termination of the effects of thyroid hormone in vertebrates. Here, we report the primary physiological effects of T4, the outer ring deiodinase activity, and a similar transcription regulation of two oyster deiodinases by TH receptor (CgTR) in an invertebrate, Pacific oyster Crassostrea gigas. L-thyroxine (T4) may have an important physiological function in the oyster, suggested by the growth retardation effect of excessive T4 in umbo larvae stage. The outer ring deiodinase activity transforming T4 to T3 (3, 3', 5-triiodothyronine) was then detected in the Pacific oyster in vivo, which may be conducted by two oyster deiodinases (CgDx and CgDy). Transcription regulation of CgTR onto these two deiodinase genes was also verified by electrophoretic mobility shift assay and dual luciferase reporter assay in mammalian cells. These results contribute to a better understanding of the evolution of the TH system.

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.

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.

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.

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.

Cloning and Sequence Analysis on cDNA of Growth Hormone Releasing Hormone Receptor Gene from Wuzhishan Miniature Pig

[Objective] cDNA of growth hormone releasing hormone （GHRH） receptor gene from Wuzhishan miniature pig was cloned and its sequence was also analyzed. [Method] Using genomic DNA extracted from porcine ear tissues of Wuzhishan miniature pig as the template, three pairs of primers were designed by the reported cDNA sequence of porcine GHRH, and cDNA was also amplified by RT-PCR. After being recovered and purified, PCR products were ligated to pMD18-T and then transformed into Escherichia coli DH5a. The transformation products were analyzed by PCR and double enzyme digestion to screen positive clones, and the positive clones were sequenced after identification in LB liquid medium. [ Result] cDNA of Wuzhishan miniature pig GHRH receptor gene was obtained successfully, and its length was 1 577 bp coding 423 amino acids. BLAST analysis showed that there were only 23 nuoleotides in difference between this fragment and pomine GHRH receptor gene, and its homology was 98%. However, both GHRH receptor genes were constituted by 423 amino acids with the sequence homology of 96%. [ Conclusion] This study provides theoretical basis for further studies on the dwarf mechanism of Wuzhishan miniature pig.

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.

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.

Isolation of Growth Hormone-Releasing Hormone and Its Receptor Genes from Scatophagus argus and Their Expression Analyses

The teleost Scatophagus argus is a species whose females grows faster than males.Growth hormone(gh)mRNA abundance in females pituitary is higher than that in males;however the mechanism underlining such differential is still unknown.Growth hormone(GH)is tightly associated with GH-releasing hormone(Ghrh)in vertebrates.In this study,Ghrh gene(ghrh)and its receptor gene,ghrhr,were isolated from S.argus.Tissue expression analysis showed that ghrh and ghrhr were mainly expressed in hypothalamus while ghrhr was expressed in pituitary and gh was predominantly expressed in pituitary.Twenty cultured S.argus individuals were used to compare ghrh,ghrhr and gh mRNA abundances,120 g and 181 g average weight for male(n=11)and female(n=9),respectively.Real-time PCR indicated that the ghrh and ghrhr mRNA abundances in male hypothalamus were significantly higher than those in female hypothalamus while that of gh mRNA abundance was significantly higher in female pituitary than in male pituitary.The ghrh and ghrhr mRNA abundances were significantly up-regulated in female hypothalamus 3 h after injection of 0.1 mg kg^-1 body weight Ghrh while pituitary ghrhr and gh mRNA abundances were not affected.In female hypothalamus,ghrh and ghrhr m RNA abundances were not affected at 6 h post-injection of 4 mg kg^-1 body weight 17α-methyltes-tosterone(17α-MT)or 17β-Estradiol(E2).In female pituitary,ghrhr m RNA abundance was down-regulated by 17α-MT while that of gh m RNA abundance was up-regulated by E2.Our findings indicated that E2,rather than Ghrh,plays an important role in up-regulating the expression of gh in female S.argus,which should aid to understand the sexual dimorphism of teleost growth.