Assessment of sources and health risks of heavy metals in metropolitan household dust among preschool children: The LEAPP-HIT study.

The most common construction material used in Taiwan is concrete, potentially contaminated by geologic heavy metals (HMs). Younger children spend much time indoors, increasing HM exposure risks from household dust owing to their behaviors. We evaluated arsenic (As), cadmium (Cd), and lead (Pb) concentrations in fingernails among 280 preschoolers between 2017 and 2023. We also analyzed HM concentrations, including As, Cd, Pb, chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn), iron (Fe), and manganese (Mn), in 90 household dust and 50 road dust samples from a residential area where children lived between 2019 and 2021 to deepen the understanding of sources and health risks of exposure to HMs from household dust. The average As, Cd, and Pb concentrations in fingernails were 0.12 ± 0.06, 0.05 ± 0.05, and 0.95 ± 0.77 µg/g, respectively. Soil parent materials, indoor construction activities, vehicle emissions, and mixed indoor combustion were the pollution sources of HMs in household dust. Higher Cr and Pb levels in household dust may pose non-carcinogenic risks to preschoolers. Addressing indoor construction and soil parent materials sources is vital for children's health. The finding of the present survey can be used for indoor environmental management to reduce the risks of HM exposure and avoid potential adverse health effects for younger children.

Direct regulation of androgen receptor-associated protein 70 by thyroid hormone and its receptors.

Thyroid hormone (T3) regulates multiple physiological processes during development, growth, differentiation, and metabolism. Most T3 actions are mediated via thyroid hormone receptors (TRs) that are members of the nuclear hormone receptor superfamily of ligand-dependent transcription factors. The effects of T3 treatment on target gene regulation was previously examined in TRalpha1-overexpressing hepatoma cell lines (HepG2-TRalpha1). Androgen receptor (AR)-associated protein 70 (ARA70) was one gene found to be up-regulated by T3. The ARA70 is a ligand-dependent coactivator for the AR and was significantly increased by 4- to 5-fold after T3 treatment by Northern blot analyses in the HepG2-TRalpha1 stable cell line. T3 induced a 1- to 2-fold increase in the HepG2-TRbeta1 stable cell line. Both stable cell lines attained the highest fold expression after 24 h treatment with 10 nM T3. The ARA70 protein was increased up to 1.9-fold after T3 treatment in HepG2-TRalpha1 cells. Similar findings were obtained in thyroidectomized rats after T3 application. Cycloheximide treatment did not suppress induction of ARA70 transcription by T3, suggesting that this regulation is direct. A series of deletion mutants of ARA70 promoter fragments in pGL2 plasmid were generated to localize the thyroid hormone response element (TRE). The DNA fragments (-234/-190 or +56/+119) gave 1.55- or 2-fold enhanced promoter activity by T3. Thus, two TRE sites exist in the upstream-regulatory region of ARA70. The TR-TRE interaction was further confirmed with EMSAs. Additionally, ARA70 could interfere with TR/TRE complex formation. Therefore, the data indicated that ARA70 suppresses T3 signaling in a TRE-dependent manner. These experimental results suggest that T3 directly up-regulates ARA70 gene expression. Subsequently, ARA70 negatively regulates T3 signaling.

Knocking down dickkopf-1 alleviates estrogen deficiency induction of bone loss. A histomorphological study in ovariectomized rats.

Dickkopf-1 (DKK1) has been found to act as a potent Wnt signaling-inhibitory factor for regulating skeletal disorders. We investigated whether modulation of DKK1 expression by end-capped phosphorothioate DKK1 antisense oligonucleotide could alter estrogen loss-induced bone loss. Ovariectomized or sham-operated rats were given 20 microg/kg/day DKK1 sense or antisense oligonucleotide or vehicle for 28 days. Femurs and tibiae were dissected to assess bone mass, biomechanical strength, immunohistochemistry and ex vivo osteoclast formation. We found that DKK1 antisense oligonucleotide significantly abrogated the suppressing effect of ovariectomy on weight, mineral content, mineral density and peak load of femurs. DKK1 antisense oligonucleotide treatment reduced ovariectomy promotion of ex vivo osteoclast differentiation of primary M-CSF-dependent bone marrow macrophages. Histomorphometric observation demonstrated that DKK1 antisense oligonucleotide treatment increased osteoblast number and impaired ovariectomy-promoted trabecular bone loss and osteoclast number in bone tissue. Osteoblastic cells adjacent to endosteum of trabecular bone and chondrocytes at calcified cartilage expressed intensive DKK1 and RANKL and weak OPG immunostaining in ovariectomized rat bone microenvironments. Osteogenic cells and chondral cells displayed weak DKK1, RANKL and OPG expression of bone tissue after DKK1 antisense oligonucleotide treatment. Taken together, attenuation of DKK1 expression in ovariectomized rat bone tissue alleviated loss of bone mass and biomechanical property. The regulatory action of DKK1 antisense oligonucleotide treatment on bone tissue appeared to suppress the promoting effect of estrogen deficiency on osteoclastogenesis-stimulatory factor RANKL expression and osteoclast differentiation. Control of DKK1 signaling can be used in the future as an alternative strategy for protecting estrogen deficiency induction of bone loss.

Antiviral effects of Salvia miltiorrhiza (Danshen) against enterovirus 71.

In this study, the antiviral activities of seven different extracts of Salvia miltiorrhiza (danshen) were determined. The first two extracts, SA1 and SA2, isolated at room temperature by ethyl acetate and water extraction, respectively, neutralized the enterovirus 71-induced cytopathic effect in Vero, rhabdomyosarcoma and MRC-5 cells. The other five crude extracts, extracted with warm water (60-70 degrees C) or organic solvents, did not have any protective activity. The 50% inhibitory concentrations for neutralizing the enterovirus 71-induced cytopathic effect were 0.742 +/- 0.042 mg/ml for SA1 and 0.585 +/- 0.018 mg/ml for SA2 in Vero cells. No antiviral activity was observed in the other viruses tested. Antiviral activity was more efficient in cultures treated with SA1 or SA2 during viral infection compared to the cultures treated before or after infection, suggesting that these danshen extracts could interfere with viral entry. SA1 and SA2 were able to inhibit viral RNA synthesis in the infected cells and to abate the apoptotic process in enterovirus 71-infected Vero cells. We conclude that danshen extracts possess antiviral activity and have potential for the development as an anti-enterovirus 71 agent.

Indirect regulation of human dehydroepiandrosterone sulfotransferase family 1A member 2 by thyroid hormones.

Thyroid hormone, T(3), regulates cell metabolism, differentiation, and development. cDNA microarrays were performed to study the mechanism of target gene regulation after T(3) treatment in a thyroid hormone receptor-alpha (TRalpha)-overexpressing hepatoma cell line (HepG2-TRalpha). The differentially expressed target genes are several metabolic enzymes, including dehydroepiandrosterone-sulfotransferase family 1A member 2 (SULT2A1). Enzyme SULT2A1 was elevated roughly 5-fold at the protein level and 9-fold increase at the mRNA level after 48 h T(3) treatment in HepG2-TRalpha cells. Cycloheximide inhibited T(3)-induced SULT2A1 expression, suggesting that regulation was indirect. SULT2A1 has been reported to be regulated by the two transcription factors, steroidogenic factor 1 (SF1) and GATA, in the human adrenal gland. T(3) induced a 2.5- to 3.5-fold elevation of SF1 at the protein level and a 6.2-fold increase at the RNA level in HepG2-TRalpha cells. About seven SF1 binding sites exist on the SULT2A1 gene. To identify and localize the critical SF1 binding site, series of deletion mutants of SULT2A1 promoter fragments in pGL2 plasmid were constructed. The promoter activity of the SULT2A1 gene was enhanced about 2.8- to 7.1-fold by T(3). The -228 SF1 binding site was identified as the most critical site because deleting this region reduced T(3)-induced expression. Transcription factor SF1 application enhanced the -228 but not -117 reporter plasmid activities. SULT2A1 and SF1 up-regulation at protein and RNA levels in thyroidectomized rats occurred after T(3) application. In summary, this work demonstrated that the SULT2A1 gene was mediated by SF1 and indirectly regulated by T(3). Further study is required to elucidate the physiological importance of SULT2A1 induction mediated by T(3).

Overexpression of lipocalin 2 in human cervical cancer enhances tumor invasion.

Cervical carcinoma is the third-most common cause of cancer-related deaths in women worldwide. However, the molecular mechanisms underlying the metastasis of cervical cancer are still unclear. Oligonucleotide microarrays coupled with bioinformatics analysis show that cytoskeletal remodeling and epithelial-to- mesenchymal transition (EMT) are significant pathways in clinical specimens of cervical cancer. In accord with clinical observations demonstrating ectopic expression of lipocalin 2 (LCN2), an oncogenic protein associated with EMT, in malignant tumors, was significantly upregulated in cervical cancer and correlated with lymph node metastasis. Overexpression of LCN2 enhanced tumor cell migration and invasion both in vitro and in vivo. Conversely, knockdown or neutralization of LCN2 reduced tumor cell migration and invasion. LCN2-induced migration was stimulated by activation of the EMT-associated proteins, Snail, Twist, N-cadherin, fibronectin, and MMP-9. Our findings collectively support a potential role of LCN2 in cancer cell invasion through the EMT pathway and suggest that LCN2 could be effectively utilized as a lymph node metastasis marker in cervical cancer.

Thyroid hormone-mediated regulation of lipocalin 2 through the Met/FAK pathway in liver cancer.

The thyroid hormone, 3,3',5-triiodo-L-thyronine (T3), regulates cell growth, development and differentiation via interactions with thyroid hormone receptors (TR), but the mechanisms underlying T3-mediated modulation of cancer progression are currently unclear. Lipocalin 2 (LCN2), a tumor-associated protein, is overexpressed in a variety of cancer types. Oligonucleotide microarray, coupled with proteomic analysis, has revealed that LCN2 is positively regulated by T3/TR. However, the physiological role and pathway of T3-mediated regulation of LCN2 in hepatocellular carcinogenesis remain to be characterized. Upregulation of LCN2 after T3 stimulation was observed in a time- and dose-dependent manner. Additionally, TRE on the LCN2 promoter was identified at positions -1444/-1427. Overexpression of LCN2 enhanced tumor cell migration and invasion, and conversely, its knockdown suppressed migration and invasion, both in vitro and in vivo. LCN2-induced migration occurred through activation of the Met/FAK cascade. LCN2 was overexpressed in clinical hepatocellular carcinoma (HCC) patients, compared with normal subjects, and positively correlated with TRα levels. Both TRα and LCN2 showed similar expression patterns in relation to survival rate, tumor grade, tumor stage and vascular invasion. Our findings collectively support a potential role of T3/TR in cancer progression through regulation of LCN2 via the Met/FAK cascade. LCN2 may thus be effectively utilized as a novel marker and therapeutic target in HCC.

Positive regulation of spondin 2 by thyroid hormone is associated with cell migration and invasion.

The thyroid hormone 3,3',5-triiodo-L-thyronine (T(3)) regulates growth, development, and differentiation processes in animals. These activities are mediated by the nuclear thyroid hormone receptors (TRs). Microarray analyses were performed previously to study the mechanism of regulation triggered by T(3) treatment in hepatoma cell lines. The results showed that spondin 2 was regulated positively by T(3). However, the underlying mechanism and the physiological role of T(3) in the regulation of spondin 2 are not clear. To verify the microarray results, spondin 2 was further investigated using semi-quantitative reverse transcription-PCR and western blotting. After 48 h of T(3) treatment in the HepG2-TR alpha 1#1 cell line, spondin 2 mRNA and protein levels increased by 3.9- to 5.7-fold. Similar results were observed in thyroidectomized rats. To localize the regulatory region in spondin 2, we performed serial deletions of the promoter and chromatin immunoprecipitation assays. The T(3) response element on the spondin 2 promoter was localized in the -1104/-1034 or -984/-925 regions. To explore the effect of spondin 2 on cellular function, spondin 2 knockdown cell lines were established from Huh7 cells. Knockdown cells had higher migration ability and invasiveness compared with control cells. Conversely, spondin 2 overexpression in J7 cells led to lower migration ability and invasiveness compared with control cells. Furthermore, this study demonstrated that spondin 2 overexpression in some types of hepatocellular carcinomas is TR dependent. Together, these experimental findings suggest that spondin 2, which is regulated by T(3), has an important role in cell invasion, cell migration, and tumor progression.

Regulation of AKR1B1 by thyroid hormone and its receptors.

The objective of this study was to identify genes regulated by thyroid hormone (T(3)) mediated by its receptor (TR) and associated with tumorigenesis. The gene encoding aldo-keto reductase family 1, member B1 (AKR1B1), as previously identified by c-DNA microarray, is known to be up-regulated by T(3) treatment. Enzyme AKR1B1 was elevated roughly 3-fold in HepG2-TRalpha1 cells at the protein level and 4.6-fold increase at the mRNA level after 48 h T(3) treatment. Similar findings were obtained from thyroidectomized rats after T(3) application. To identify and localize the critical TR element (TRE), series deletion of the promoter mutant were constructed and electrophoretic mobility shift assays were carried out. The TRE on the AKR1B1 promoter was localized to the -1099/-1028 region. Further, this study demonstrated that AKR1B1 over-expression in some types of hepatocellular carcinomas (HCCs) is TR-dependent and might play a crucial role in the development of HCC. Thus, T(3) regulates AKR1B1 gene expression via a TRE-dependant mechanism and associates liver cancer.