Parabens promotes invasive properties of multiple human cells: A potential cancer-associated adverse outcome pathway.

Parabens are esters of p-hydroxybenzoic acid, which have been used as preservatives and considered safe for nearly a century, until the last two decades when concerns began to be raised about their association with cancers. Knowledge of the mode of action of parabens on the metastatic properties of different cancer cells is still very limited. In the present study, we investigated the effects of methylparaben (MP) and propylparaben (PP) on cell invasion and/or migration in multiple human cancerous and noncancerous cells, including hepatocellular carcinoma cells (HepG2), cervical carcinoma cells (HeLa), breast carcinoma cells (MCF-7), and human placental trophoblasts (HTR-8/SVneo). MP and PP at concentrations in a range of 5-500 µg/L significantly promoted the invasion of four cell lines, with a minimum effective concentration of 5 µg/L. MP and PP up-regulated the expression levels and enzymatic activities of matrix metalloproteinase 2 and 9 (MMP2 and MMP9), as well as altered the expression of the tissue inhibitors of metalloproteinase 1 and 2 (TIMP1 and TIMP2) in four cell lines, suggesting MMPs/TIMPs as potential key events (KEs) for paraben-induced cell invasion. Activation of the p38 mitogen-activated protein kinase (p38 MAPK) and c-Jun N-terminal protein kinases 1/2 (JNK1/2) signaling pathways was required for MP- and PP-promoted invasion of four cell lines, suggesting MAPK signaling pathways as candidates for KEs in cancer or noncancerous cells response to paraben exposure. This study showed for the first time that the two widely used parabens, MP and PP, promoted invasive capacity of multiple human cells through a common mode of action. This study provides evidence for the establishment of a potential cancer-associated AOP for parabens based on pathway-specific mechanism(s), which contributes towards assessing the health risks of these environmental chemicals.

Disruption of gonadotropin hormone biosynthesis by parabens: A potential development and reproduction-associated adverse outcome pathway.

Parabens are widely used as antibacterial preservatives in foods and personal care products. The knowledge about the modes of toxic action of parabens on development and reproduction remain very limited. The present study attempted to establish a development and reproduction-associated adverse outcome pathway (AOP) by evaluating the effects of methylparaben (MP), ethylparaben (EP), propylparaben (PP) and butylparaben (BP) on the biosynthesis of gonadotropins, which are key hormones for development and reproduction. MP and BP significantly upregulated the mRNA and protein levels of follicle stimulating hormone (FSH) and luteinizing hormone (LH) in pituitary gonadotropic cells in a concentration-dependent manner. Activation of gonadotropin-releasing hormone receptor (GnRHR) was required for gonadotropin biosynthesis induced by BP, but not MP. Molecular docking data further demonstrated the higher binding efficiency of BP to human GnRHR than that of MP, suggesting GnRHR as a potential molecular initiative event (MIE) for BP-induced gonadotropin production. L-type voltage-gated calcium channels (VGCCs) were found to be another candidate for MIE in gonadotropic cells response to both MP and BP exposure. The calcium-dependent activation of extracellular signal-regulated kinase 1 (ERK1) and ERK2 was subsequently required for MP- and BP-induced activation of GnRHR and L-type VGCCs pathways. In summary, MP and BP promoted gonadotropin biosynthesis through their interactions with cellular macromolecules GnRHR, L-type VGCCs, and subsequent key event ERK1/2. This is the first study to report the direct interference of parabens with gonadotropin biosynthesis and establish a potential AOP based on pathway-specific mechanism, which contributes to the effective screening of environmental chemicals with developmental and reproductive health risks.

ISL1 regulates lung branching morphogenesis via Shh signaling pathway.

Lung branching morphogenesis relies on a complex coordination of multiple signaling pathways and transcription factors. Here, we found that ablation of the LIM homeodomain transcription factor Islet1 (Isl1) in lung epithelium resulted in defective branching morphogenesis and incomplete formation of five lobes. A reduction in mesenchymal cell proliferation was observed in Isl1ShhCre lungs. There was no difference in apoptosis between the wild-type (ShhCre) and Isl1ShhCre embryos. RNA-Seq and in situ hybridization analysis showed that Shh, Ptch1, Sox9, Irx1, Irx2, Tbx2, and Tbx3 were downregulated in the lungs of Isl1ShhCre embryos. ChIP assay implied the Shh gene served as a direct target of ISL1, since the transcription factor ISL1 could bind to the Shh epithelial enhancer sequence (MACS1). Also, activation of the Hedgehog pathway via ectopic gene expression rescued the defects caused by Isl1 ablation, confirming the genetic integration of Hedgehog signaling. In conclusion, our works suggest that epithelial Isl1 regulates lung branching morphogenesis through administrating the Shh signaling mediated epithelial-mesenchymal communications.

ISL1/SHH/CXCL12 signaling regulates myogenic cell migration during mouse tongue development.

Migration of myoblasts derived from the occipital somites is essential for tongue morphogenesis. However, the molecular mechanisms of myoblast migration remain elusive. In this study, we report that deletion of Isl1 in the mouse mandibular epithelium leads to aglossia due to myoblast migration defects. Isl1 regulates the expression pattern of chemokine ligand 12 (Cxcl12) in the first branchial arch through the Shh/Wnt5a cascade. Cxcl12+ mesenchymal cells in Isl1ShhCre embryos were unable to migrate to the distal region, but instead clustered in a relatively small proximal domain of the mandible. CXCL12 serves as a bidirectional cue for myoblasts expressing its receptor CXCR4 in a concentration-dependent manner, attracting Cxcr4+ myoblast invasion at low concentrations but repelling at high concentrations. The accumulation of Cxcl12+ mesenchymal cells resulted in high local concentrations of CXCL12, which prevented Cxcr4+ myoblast invasion. Furthermore, transgenic activation of Ihh alleviated defects in tongue development and rescued myoblast migration, confirming the functional involvement of Hedgehog signaling in tongue development. In summary, this study provides the first line of genetic evidence that the ISL1/SHH/CXCL12 axis regulates myoblast migration during tongue development.

Target RNA activates the protease activity of Craspase to confer antiviral defense.

In the type III-E CRISPR-Cas system, a Cas effector (gRAMP) is associated with a TPR-CHAT to form Craspase (CRISPR-guided caspase). However, both the structural features of gRAMP and the immunity mechanism remain unknown for this system. Here, we report structures of gRAMP-crRNA and gRAMP:cRNA:target RNA as well as structures of Craspase and Craspase complexed with cognate target RNA (CTR) or non-cognate target RNA (NTR). Importantly, the 3' anti-tag region of NTR and CTR binds at two distinct channels in Craspase, and CTR with a non-complementary 3' anti-tag induces a marked conformational change of the TPR-CHAT, which allosterically activates its protease activity to cleave an ancillary protein Csx30. This cleavage then triggers an abortive infection as the antiviral strategy of the type III-E system. Together, our study provides crucial insights into both the catalytic mechanism of the gRAMP and the immunity mechanism of the type III-E system.

[Optimization of urban ecological spatial structure based on network analysis: A case study of Changzhou City, China]. / 基于网络分析的城市生态空间结构优化­­ä»¥å¸¸å·žå¸‚为例.

The rapid development of economy and society leads to the rapid expansion of cities, resulting in the atrophy of urban ecological space and the decline of ecological function, as well as a serious threat to urban ecological security. It is of great significance for the sustainable development of a city to systematically analyze the structure of urban ecological space and put forward targeted protection and optimization measures. Taking Changzhou City as the research area and considering the natural ecological function and social service function of urban ecological space, we constructed two ecological networks, the "source-corridor" ecological network based on natural ecology and the "supply-demand" ecological network based on human ecology. For the "source-corridor" ecological network, quantitative analysis was mainly carried out from the importance of nodes, network connectivity and stability. For the "supply-demand" ecological network, quantitative analysis was mainly carried out from the importance of nodes, supply-demand equilibrium and stability. The results showed that the levels of connectivity and stability of the "source-corridor" ecological network in the main urban area of Changzhou were not high, the stability level of the "supply-demand" ecological network was general, and there was spatial mismatch between service supply and demands. From the perspective of connectivity and stability improvement, an optimization scheme of "source-corridor" ecological network with 12 additional source nodes and 57 corridors was proposed. From the perspective of supply-demand balance and stability improvement, an optimization scheme of "supply-demand" ecological network with 22 new supply nodes was proposed. Compared with the original "source-corridor" ecological network, the connectivity level of the optimized network was improved by 10%, and the network stability was improved by 0.05. Compared with the initial "supply-demand" ecological network, the service level of the optimized network was improved by 4%, and the network stability was improved by 0.10. Finally, we integrated the two ecological networks, and formulated the implementation plan of protection and management for both the current protected patches and the new ecological nodes.

Variability of urinary biomarkers of neonicotinoid insecticides in Chinese population: Implications for human exposure assessment.

Neonicotinoids are a class of the most widely used insecticides worldwide with a short biological half-life. The levels of neonicotinoids and their metabolites in urine have been detected as biomarkers for human exposure assessment. To understand the reliability of a single measurement of urinary neonicotinoid biomarkers in representing a true longer-term average exposure, in this study we evaluated the temporal variability of 14 neonicotinoids and/or their metabolites over one year in 114 Chinese young adults. The detection rates of 14 neonicotinoid biomarkers ranged from 18% to 100%. The intraclass correlation coefficients (ICCs) of most neonicotinoid biomarkers indicated poor (ICC <0.4) reproducibility in spot urine samples during 1-week, 1-month, or 1-year periods, except for 5-hydroxy-imidacloprid (5-OH-IMI) within 1-week showing fair to good reproducibility (ICC = 0.40). Log-transformed 5-OH-IMI, dinotefuran, 1-methyl-3-(tetrahydro-3-furylmethyl) urea, N-desmethyl-acetamiprid, and N-desmethyl-thiamethoxam required a minimum of 2-4 spot urine samples over one year to obtain a reliable exposure evaluation. Using two or three spot urine samples to categorize the "true" exposure of the highest tertile indicated the higher specificities (0.60-1.00) than the sensitivities (0.24-0.93). We recommend that at least 2-4 spot urine samples are used to assess 1-year neonicotinoid exposure and seasonal variations should be considered when scheduling urine sample collection. This study provides a reference for appropriate sampling method and research design for the exposure assessment of neonicotinoids in biomonitoring and epidemiological studies.

A visualized pulmonary arterial thrombus by using a modified echocardiographic view in an intermediate-risk acute pulmonary embolism patient: A case report.

Acute pulmonary embolism (APE) is a life-threatening disease with nonspecific clinical signs and symptoms. Rapid and accurate diagnosis is crucial for the clinical management of patients with acute pulmonary embolism. A recommended echocardiography view may be of further help in the diagnosis and evaluation of the change in thrombosis and treatment. We reported a case of a 74-year-old man with a 12-day history of decreased exercise capacity and dyspnea. The patient was diagnosed with intermediate-risk APE as several pulmonary emboli in pulmonary artery were seen in multidetector computed tomographic pulmonary angiography with normal blood pressure and echocardiographic right ventricular overload. And we found a pulmonary artery clot in the right pulmonary artery through transthoracic echocardiography. After 11-days anticoagulation, the patient underwent a reassessment, showed a decrease in RV diameter and pulmonary artery thrombus. This case highlights the significant role that echocardiography played in a patient who presented pulmonary embolism with a stable hemodynamic situation and normal blood pressure. The modified echocardiographic view could provide correct diagnosis by identifying the clot size and location visually. Knowledge of the echocardiography results of APE would aid the diagnosis.

Structural and mechanistic insights into the inhibition of type I-F CRISPR-Cas system by anti-CRISPR protein AcrIF23.

Prokaryotes evolved clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) proteins as a kind of adaptive immune defense against mobile genetic elements including harmful phages. To counteract this defense, many mobile genetic elements in turn encode anti-CRISPR proteins (Acrs) to inactivate the CRISPR-Cas system. While multiple mechanisms of Acrs have been uncovered, it remains unknown whether other mechanisms are utilized by uncharacterized Acrs. Here, we report a novel mechanism adopted by recently identified AcrIF23. We show that AcrIF23 interacts with the Cas2/3 helicase-nuclease in the type I-F CRISPR-Cas system, similar to AcrIF3. The structure of AcrIF23 demonstrated a novel fold and structure-based mutagenesis identified a surface region of AcrIF23 involved in both Cas2/3-binding and its inhibition capacity. Unlike AcrIF3, however, we found AcrIF23 only potently inhibits the DNA cleavage activity of Cas2/3 but does not hinder the recruitment of Cas2/3 to the CRISPR RNA-guided surveillance complex (the Csy complex). Also, in contrast to AcrIF3 which hinders substrate DNA recognition by Cas2/3, we show AcrIF23 promotes DNA binding to Cas2/3. Taken together, our study identifies a novel anti-CRISPR mechanism used by AcrIF23 and highlights the diverse mechanisms adopted by Acrs.

Exposure to multiple pyrethroid insecticides affects ovarian follicular development via modifying microRNA expression.

Pyrethroids, a class of insecticides widely used in agriculture and residential pest control, have been considered as endocrine-disrupting chemicals (EDCs). Our previous epidemiological study reported a positive association of urinary levels of pyrethroid metabolites with the risk of primary ovarian insufficiency in women, suggesting that pyrethroid exposure may be a potential risk factor for female ovarian health. In this study, female mice at gestational, lactational or peripubertal stages were exposed to eight most commonly used pyrethroids at the doses of acceptable daily intake (ADI) recommended by the World Health Organization (WHO). Gestational exposure to eight pyrethroids at ADI doses led to a significant decrease in the number of primary follicles in female offspring on postnatal day (PND) 3, and an increase in the number of atretic follicles and granulosa cell apoptosis, as well as lower estrogen and higher follicle-stimulating hormone (FSH) levels in adult female offspring. Lactational and peripubertal exposure to pyrethroid mixture had no significant effects on follicular development and ovarian functions. The data of high-throughput microRNA (miRNA) sequencing showed that 23 miRNAs were differentially expressed in the ovaries of female offspring mice on PND 1 after gestational exposure to pyrethroid mixture. The results of qPCR confirmed that miR-152-3p, miR-450b-3p and miR-196a-5p were significantly upregulated in the neonatal ovaries in the exposed group. The bioinformatic analysis indicates that the modification of the expression of ovarian miRNAs by pyrethroid exposure may disrupt the key biological processes (such as mRNA processing) and major signaling pathways (such as PI3K/Akt pathway, adipocytokine pathway and GnRH pathway) governing follicular development and ovarian functions. This study first reported that gestational exposure of female mice to multiple pyrethroids at the recommended human safe doses had irreversible adverse effects on the ovaries in female offspring in adulthood through regulating the expression of miRNAs during early developmental stages.

An efficient method of inducing differentiation of mouse embryonic stem cells into primitive endodermal cells.

Primitive Endoderm (PrE) is an extraembryonic structure derived from inner cell mass (ICM) in the blastocysts. Its interaction with the epiblast is critical to sustain embryonic growth and embryonic pattern. In this study, we reported a simple and efficient method to induce the differentiation of mouse Embryonic Stem Cells (mESCs) into PrE cells. In the process of ESC monolayer adherent culture, 1 µM atRA and 10 µM CHIR inducers were used to activate RA and Wnt signaling pathways respectively. After 9 days of differentiation, the proportion of PrE cells was up to 85%. Further studies indicated that Wnt signaling pathway acted as a switch that RA induces mESCs differentiation between SMC and PrE cell. In the presence of only RA signaling, mESCs adopted the fate of smooth muscle cells (SMCs); Simultaneous activation of the Wnt signaling pathway changed the differentiation fate of mESCs into PrE cells. This efficient induction method can provide new cellular resources and models for relevant studies of PrE.

Lifelong exposure to pyrethroid insecticide cypermethrin at environmentally relevant doses causes primary ovarian insufficiency in female mice.

Pyrethroids are a class of widely used insecticides. Our recent epidemiological study of Chinese women reported that pyrethroid exposure was positively associated with the risk of primary ovarian insufficiency (POI). In this study, we utilized cypermethrin (CP), the most frequently detected pyrethroid in the environment, to recognize how lifelong and low-dose exposure to pyrethroids affects ovarian functions and the underlying mechanism(s). Female mice were exposed to CP at doses of human dietary intake of 6.7 µg/kg/day, an acceptable daily intake (ADI) of 20 µg/kg/day, or the chronic reference dose (RfD) of 60 µg/kg/day, starting from gestational day 0.5 until 44-week-old. We assessed effects on fertility, serum hormone levels, ovarian follicular development and ovarian transcriptomic profiles. Chronic exposure to CP at doses of ADI and RfD caused a significant reduction in the size of the primordial follicle pool on postnatal day (PND) 5 and the number of all types of follicles in 44-week-old mice, lower estrogen and higher gonadotropin levels, as well as decreased fertility. Significant increase in apoptosis and decrease in cell proliferation were observed in CP-exposed ovarian follicles from PND 5 and 44-week-old mice. Ovarian transcriptomic data showed that the pro-apoptotic protein BMF and the cell cycle inhibitor p27 were significantly up-regulated in CP-exposed ovaries. Cyp17a1, Cyp19a1 and Hsd17b1 genes involved in the key steps of steroidogenesis were down-regulated in the ovaries of female mice exposed to CP. This study first reported that lifelong exposure to CP at doses of ADI or RfD caused an ovarian phenotype similar to human POI in female mice and provided a mechanistic explanation. Our findings suggest that lifelong exposure to pyrethroids of low doses, which are recommended as 'safe' dosages, may have a significant impact on the ovarian health of female mammals and humans.

Induction of right open reading frame kinase 3 (RIOK3) during ovulation and luteinisation in rat ovary.

Atypical protein serine kinase RIOK3 is involved in cellular invasion and survival. The spatiotemporal expression pattern and regulatory mechanisms controlling expression of Riok3 were investigated in the rat ovary during the periovulatory period. Immature female rats (22-23 days old) were treated with pregnant mare's serum gonadotropin (PMSG) to stimulate follicular development, followed 48h later by injection with human chorionic gonadotrophin (hCG). Ovaries, granulosa cells, or theca-interstitial cells were collected at various times after hCG administration. Both real-time polymerase chain reaction (PCR) and in situ hybridisation analysis revealed that Riok3 was highly induced in both granulosa cells and theca-interstitial cells by hCG. Riok3 expression was induced in theca-interstitial cells at 4h after hCG. However, the expression of Riok3 mRNA was stimulated in granulosa cells at 8h. Both protein kinase C inhibitor (GF109203) and the protein kinase A inhibitor (H89) could block the stimulation of Riok3 mRNA by hCG. Furthermore, Riok3 induction is dependent on new protein synthesis. Inhibition of prostaglandin synthesis or progesterone action did not alter Riok3 mRNA expression, whereas inhibition of the epidermal growth factor (EGF) pathway downregulated Riok3 expression. In conclusion, our findings suggest that the induction of the RIOK3 may be important for ovulation and luteinisation.

The function of Wls in ovarian development.

WNT ligand transporter Wls is essential for the WNT dependent developmental and pathogenic processes. The spatiotemporal expression pattern of Wls was investigated in this study. Immature female mice (21-22 days old) were treated with 5 IU, pregnant mare's serum gonadotrophin (PMSG) to stimulate follicular development, followed 48 h later by injection with 5 IU, human chorionic gonadotrophin (hCG) to induce ovulation. The expression of Wls was stimulated in granulosa cells and the forming corpus luteum after hCG administration. To study the function of Wls, the Amhr2tm3(cre)Bhr strain was used to target deletion of Wls in granulosa cells. The deletion of Wls caused a significant decrease in the fertility of WlsAmhr2-Cre female mice. In female WlsAmhr2-Cre mice, decreased ovarian size and number of antral follicles were found. The number of corpus luteum in immature PMSG/hCG primed WlsAmhr2-Cre mice was much less than that in the control group. Compared with control animals, WlsAmhr2-Cre mice have lower serum progesterone levels. RNA sequencing was used to identify genes regulated by Wls after hCG treatment. Several genes known to be critical for follicle development and steroidogenesis were significantly down-regulated, such as Fshr, Lhcgr, Sfrp4, Inhba, Cyp17a1, Hsd3b1, and Hsd17b7. The expression of WNT signaling downstream target genes, Bmp2 and Cyp19a1, also decreased significantly in WlsAmhr2-Cre ovary. In summary, the findings of this study suggest that Wls is critical for female fertility and luteinization.

Gender-specific associations of CD36 polymorphisms with the lipid profile and susceptibility to premature multi-vessel coronary artery heart disease in the Northern Han Chinese.

BACKGROUND: The aim of the present study was to detect potential gender-specific associations between some common CD36 single nucleotide polymorphisms (SNPs) and the lipid profile, as well as the susceptibility to premature multi-vessel coronary artery heart disease (CHD) in the Han population of Northern China. METHODS: A systematic three-step study process was employed to detect associations between CD36 gene variants and blood lipid profiles, as well as premature multi-vessel CHD in a gender-specific manner. RESULTS: The current study documented the following novel findings: (I) the full population-based association study in 329 Northern Han Chinese showed that four common CD36 polymorphisms were significantly related to extreme lipid profiles, with statistically significant effects based on gender interactions (rs1049673: P = 0.001; rs7755: P = 0.008; rs3211956: P = 0.034; and rs3173798: P = 0.004); (ii) these statistically significant effects could be decomposed into statistically significant atherogenic effects in males, but non-significant non-atherogenic effects in females; (iii) the results of logistic regression analysis indicated that current smoking status, low density lipoprotein cholesterol (LDL-C) levels, and type-2 diabetes were independent risk factors for premature multi-vessel CHD phenotype (P < 0.0001). CONCLUSIONS: Four common CD36 polymorphisms (rs1049673, rs7755, rs3211956, and rs3173798) were identified to be significantly associated with extreme lipid profiles and had statistically opposite gender-specific clinical lipid profile effects. Thus, the 3'-untranslated regions (3'-UTR) CD36 SNPs could be a novel target for metabolic abnormalities in males of the Han nationality from Northern China.

Induction of tumor suppressor KCTD11 during periovulatory period in rat ovary.

The tumor suppressor gene KCTD11 plays a critical role in cell proliferation, differentiation and invasion. The current study investigated the regulation and the spatiotemporal expression pattern of Kctd11 in the rat ovary during the periovulatory period. Ovaries, granulosa cells, or theca-interstitial cells were collected at various times after hCG administration using an established gonadotropin-primed immature rat model that induces follicular development and ovulation. Real-time quantitative PCR analysis revealed that mRNA for Kctd11 was significantly induced both in theca-intersititial and granulosa cells after hCG treatment although their temporal expression patterns differed. In situ hybridization analysis demonstrated that Kctd11 mRNA expression was induced in theca-intersititial cells at 6 h after hCG, and the expression remained elevated until 12 h after hCG. Kctd11 mRNA was stimulated in granulosa cells at 6 h and reached the highest expression at 12 h. There was negligible Kctd11 mRNA signal observed in newly forming corpora lutea. In addition, the data indicate that both the protein kinase A and the protein kinase C pathway regulate the expression of Kctd11 mRNA in granulosa cells. Either forskolin or phorbol 12 myristate 13-acetate can mimic hCG induction of Kctd11 expression. Furthermore, the stimulation of Kctd11 by hCG requires new protein synthesis. Inhibition of progesterone action and the EGF pathway blocked Kctd11 mRNA expression, whereas inhibition of prostaglandin synthesis had no effect. Our finding suggest that the induction of the Kctd11 may be important for theca and granulosa cell differentiation into luteal cells.

Expression and regulation of high mobility group AT-hook 1 (HMGA1) during ovulation and luteinisation in rat ovary.

High mobility group AT-hook 1 (HMGA1) is able to regulate gene expression and function as a tumour suppressor. The spatiotemporal expression pattern of HMGA1 was investigated in this study. Immature female rats (22-23 days old) were treated with 10IU, s.c., pregnant mare's serum gonadotrophin to stimulate follicular development, followed 48h later by injection with 5IU, s.c., human chorionic gonadotrophin (hCG). Whole ovaries or granulosa cells were collected at various times after hCG administration (n=3 per time point). Real-time polymerase chain reaction and western blot analysis revealed that HMGA1 was highly stimulated in the ovary by 4-12h after hCG treatment. In situ hybridisation analysis demonstrated that Hmga1 mRNA expression was induced in granulosa cells between 8 and 12h after hCG treatment. There was negligible Hmga1 mRNA signal observed in newly forming corpora lutea. In addition, the data indicated that both the protein kinase (PK) A and PKC pathways regulated Hmga1 expression in rat granulosa cells. In rat granulosa cell cultures, upregulation of Hmga1 was dependent on new protein synthesis because Hmga1 was inhibited by cycloheximide. Furthermore, Hmga1 mRNA expression in rat granulosa cell cultures was inhibited by AG1478, whereas NS398 and RU486 had no effect, suggesting that Hmga1 expression was regulated, in part, by the epidermal growth factor pathway. In summary, the findings of this study suggest that induction of Hmga1 may be important for theca and granulosa cell differentiation into luteal cells.

Extending the SLEUTH model to integrate habitat quality into urban growth simulation.

This study aims to support sustainable urban and environmental planning by using urban growth simulation models, in which environmental quality is employed as one of the inputs. We proposed an extended SLEUTH urban growth model (UGM) for the regions threatened by environmental quality degradation caused by uncontrolled urban expansion. In this model, habitat quality is assessed by the InVEST model and is used to represent environmental quality, which is utilized in urban growth simulation. The habitat quality map is used to replace the slope layer as input for the SLEUTH model's urban growth simulation for cities where relatively flat topography makes this layer of minimal explanatory value. The extended SLEUTH UGM was calibrated using data for Changzhou city, China in 1990, 2000, 2010, and 2014. The best value of the Optimal SLEUTH Metric (OSM) was calculated for both the standard SLEUTH UGM and the extended SLEUTH UGM independently. The OSM value for the latter model was much higher than that of the former model, which indicated that the extended model provided a better explanation of urban growth in the study area. The calibrated extended SLEUTH UGM was applied to predict growth in Changzhou city from 2014 to 2030. The result showed that the urban area is expected to expand about 626 km2 by 2030. Comparison with the prediction result by using standard SLEUTH UGM showed that the area with high habitat quality could be reserved and the urban expansion could be limited by using our model. The findings demonstrate that the extended SLEUTH UGM could be a valuable tool for sustainable urban and environmental planning and management in developing regions where environmental protection should be considered as one of the major land-use objectives in their rapid urbanization process.

Pyrethroid Insecticide Cypermethrin Modulates Gonadotropin Synthesis via Calcium Homeostasis and ERK1/2 Signaling in LßT2 Mouse Pituitary Cells.

Pyrethroids are a class of widely used insecticides. Cypermethrin (CP) is one of most commonly used pyrethroid insecticides and its residue has been frequently detected in environmental media. Our recent animal study reported that early postnatal exposure to CP induced an increase in serum levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) as well as the expression of gonadotropin subunit genes (chorionic gonadotropin α [CGα], LHß and FSHß) in pituitary tissues. In this study, we further investigated the precise mechanism by which CP at concentrations of 1-100 nM affected the synthesis of gonadotropins using a murine pituitary gonadotropic cell line LßT2. We found that calcium (Ca2+)-dependent extracellular signal-regulated kinase 1/2 (ERK1/2) activity was required for CP-regulated transcription of CGαs, LHß and FSHß. We provided the novel evidence that CP caused both influx of extracellular Ca2+ through L-type voltage-gated calcium channels (VGCCs) and release of intracellular Ca2+ from endoplasmic reticulum (ER) via inhibition of Ca2+-ATPase. Our results showed that CP disrupted Ca2+ homeostasis via these two separate and independent pathways, thus resulting in the activation of protein kinase C /c-Raf/ERK1/2/immediate-early genes pathways and subsequent increase in the transcription of gonadotropin subunit genes. Our findings would have important implications for understanding the underlying mechanisms of the disrupting effects of some pyrethroids (such as CP) on the synthesis of pituitary gonadotropins.

Pyrethroid Insecticide Cypermethrin Accelerates Pubertal Onset in Male Mice via Disrupting Hypothalamic-Pituitary-Gonadal Axis.

Pyrethroids, a class of insecticides that are widely used worldwide, have been identified as endocrine-disrupting chemicals (EDCs). Our recent epidemiological study reported on an association of increased pyrethroids exposure with elevated gonadotropins levels and earlier pubertal development in Chinese boys. In this study, we further investigated the effects of cypermethrin (CP), one of the most ubiquitous pyrethroid insecticides, on hypothalamic-pituitary-gonadal (HPG) axis and pubertal onset in male animal models. Early postnatal exposure to CP at environmentally relevant doses (0.5, 5, and 50 µg/kg CP) significantly accelerated the age of puberty onset in male mice. Administration of CP induced a dose-dependent increase in serum levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone in male mice. CP did not affect gonadotropin-releasing hormone (GnRH) gene expression in the hypothalamus, but CP at higher concentrations stimulated GnRH pulse frequency. CP could induce the secretion of LH and FSH, as well as the expression of gonadotropin subunit genes [chorionic gonadotropin α (CGα), LHß, and FSHß] in pituitary gonadotropes. CP stimulated testosterone production and the expression of steroidogenesis-related genes [steroidogenic acute regulatory (StAR) and Cytochrome p 450, family 11, subfamily A, polypeptide 1 (CYP11A1)] in testicular Leydig cells. The interference with hypothalamic sodium channels as well as calcium channels in pituitary gonadotropes and testicular Leydig cells was responsible for CP-induced HPG axis maturation. Our findings established in animal models provide further evidence for the biological plausibility of pyrethroid exposure as a potentially environmental contributor to earlier puberty in males.