Deep-Learning Models for the Echocardiographic Assessment of Diastolic Dysfunction.

OBJECTIVES: The authors explored a deep neural network (DeepNN) model that integrates multidimensional echocardiographic data to identify distinct patient subgroups with heart failure with preserved ejection fraction (HFpEF). BACKGROUND: The clinical algorithms for phenotyping the severity of diastolic dysfunction in HFpEF remain imprecise. METHODS: The authors developed a DeepNN model to predict high- and low-risk phenogroups in a derivation cohort (n = 1,242). Model performance was first validated in 2 external cohorts to identify elevated left ventricular filling pressure (n = 84) and assess its prognostic value (n = 219) in patients with varying degrees of systolic and diastolic dysfunction. In 3 National Heart, Lung, and Blood Institute-funded HFpEF trials, the clinical significance of the model was further validated by assessing the relationships of the phenogroups with adverse clinical outcomes (TOPCAT [Aldosterone Antagonist Therapy for Adults With Heart Failure and Preserved Systolic Function] trial, n = 518), cardiac biomarkers, and exercise parameters (NEAT-HFpEF [Nitrate's Effect on Activity Tolerance in Heart Failure With Preserved Ejection Fraction] and RELAX-HF [Evaluating the Effectiveness of Sildenafil at Improving Health Outcomes and Exercise Ability in People With Diastolic Heart Failure] pooled cohort, n = 346). RESULTS: The DeepNN model showed higher area under the receiver-operating characteristic curve than 2016 American Society of Echocardiography guideline grades for predicting elevated left ventricular filling pressure (0.88 vs. 0.67; p = 0.01). The high-risk (vs. low-risk) phenogroup showed higher rates of heart failure hospitalization and/or death, even after adjusting for global left ventricular and atrial longitudinal strain (hazard ratio [HR]: 3.96; 95% confidence interval [CI]: 1.24 to 12.67; p = 0.021). Similarly, in the TOPCAT cohort, the high-risk (vs. low-risk) phenogroup showed higher rates of heart failure hospitalization or cardiac death (HR: 1.92; 95% CI: 1.16 to 3.22; p = 0.01) and higher event-free survival with spironolactone therapy (HR: 0.65; 95% CI: 0.46 to 0.90; p = 0.01). In the pooled RELAX-HF/NEAT-HFpEF cohort, the high-risk (vs. low-risk) phenogroup had a higher burden of chronic myocardial injury (p < 0.001), neurohormonal activation (p < 0.001), and lower exercise capacity (p = 0.001). CONCLUSIONS: This publicly available DeepNN classifier can characterize the severity of diastolic dysfunction and identify a specific subgroup of patients with HFpEF who have elevated left ventricular filling pressures, biomarkers of myocardial injury and stress, and adverse events and those who are more likely to respond to spironolactone.

The combination of exercise training and alpha-lipoic acid treatment has therapeutic effects on the pathogenic phenotypes of Alzheimer's disease in NSE/APPsw-transgenic mice.

Exercise training was suggested as a practical therapeutic strategy for human subjects suffering from Alzheimer's disease (AD) in our previous study. Therefore, the purpose of this study was to investigate the effects of combining exercise training with the administration of antioxidants on the pathological phenotype of AD. To accomplish this, non-transgenic mice (Non-Tg) and NSE/APPsw Tg mice were treated with alpha-lipoic acid and treadmill exercised for 16 weeks, after which their brains were evaluated to determine whether any changes in the pathological phenotype-related factors occurred. The results indicated that (i) the combination-applied (COMA) Tg group with exercise training (ET) and alpha-lipoic acid administration (LA) showed ameliorated spatial learning and memory compared to the sedentary (SED)-Tg and single-treatment groups; (ii) there were no differences in the level of Abeta-42 peptides across groups; (iii) the level of glucose transporter-1 and brain-derived neurotrophic factor proteins were highly increased in the COMA group, (iv) ET and LA did not induce a synergistic effect on the expression of heat shock protein-70 and apoptotic proteins including Bax and caspase-3; (v) the levels of SOD-1 and CAT suppressing oxidative stress were extensively higher in the COMA than in the single-treated groups and (vi) there were no significant differences across groups regarding these serum characteristics, although these levels were lower than the SED-Tg group. Taken together, these results suggest that the combination with ET and LA may contribute to protect the neuron injury induced by Abeta peptides and may be considered an effective therapeutic strategy for human subjects suffering from AD.

PEN-2 overexpression induces gamma-secretase protein and its activity with amyloid beta-42 production.

PEN-2 is a component of the gamma-secretase complex, which is involved in the cleavage of the beta-amyloid precursor protein. The aim of this study was to determine the mechanism by which PEN-2 overexpression regulates gamma-secretase expression and the production of Abeta-42. In order to determine this, a hybrid gene harboring human PEN-2 was constructed, and used in the transfection of SK-N-MC human neuroepitheliomal cells. This cell line was also co-transfected with a combination of human mutant presenilin 2 (hPS2m) and APPsw. Our results indicated that (i) human PEN-2 overexpression induced an increase in gamma-secretase activity and its proteins, including PS1-CTF, APH-1, and nicastrin, thus production of Abeta-42, (ii) co-transfection of human PEN-2 with both hPS2m and APPsw exerted no more profound effects on the induction of gamma-secretase proteins and its activity than did transfection with hPEN-2 alone. Thus, PEN-2 overexpression may facilitate assembly into the more active gamma-secretase complex, and may also induce an increase in activity, thus affecting Abeta-42 production.

Differential effect of 7,12-dimethylbenz[a]anthracene on human and mouse CYP1B1 from livers of castrated transgenic mice.

Humanized transgenic mice coexpressing tetracycline-controlled transactivator (tTA) and human cytochrome P450 1B1 (CYP1B1) (hCYP1B1) have been created by this group. The aims of this study was to determine if 7,12-dimethylbenz[a]anthracene (DMBA) functions as testosterone or doxycycline in its ability to induce or reduce expression of hCYP1B1 or endogenous mouse CYP1B1 (mCYP1B1). This was tested in the livers by treating castrated transgenic males and hCYP1B1/luciferase-transfected cells with DMBA. Herein, DMBA-treated group exhibited (i) gradual reduction of hCYP1B1 expression at the transcript, protein, and activity levels but gradually induced its transcript level during DMBA release; (ii) gradual reduction of hCYP1B1 at the transcript and protein levels, as in the case of doxycycline or testosterone; (iii) gradual induction of mCYP1B1 expression at the transcript and protein levels but gradually reduced its transcript level during DMBA release. In parallel, DMBA-treated transfected cells exhibited gradual increase in luciferase activity in a time-and dose-dependent manner. Thus, castrated transgenic males or in vitro system could be useful as models for the detection of polycyclic aromatic hydrocarbons (PAHs) or environmental toxicants by measuring either hCYP1B1 or mCYP1B1 expressions.

Analysis of differentially expressed genes in early- and late-stage APPsw-transgenic and normal mice using cDNA microarray.

The complexity of Alzheimer's disease (AD) has made it difficult to examine its underlying mechanism. A gene microarray offers a solution to the complexity through a parallel analysis of most of the genes expressed in the brains from AD-transgenic mice. In our previous study, a total of 52 differentially expressed genes were identified in 18-month-old APPsw-transgenic mice compared to age-matched normal mice. We extended our work to better understand the relevant gene profiles from both early- and late-stage transgenic and normal mice. To accomplish this, cDNA microarray was used with the large-scale screening of the brain mRNA from transgenic and normal mice of 1 and 18 months of age. We identified a total of 48 genes, 6 up-regulated and 42 down-regulated, differentially expressed with a significant degree of induction and reduction in the brains from moderate 18-month-old transgenic mice compared to 1-month-old transgenic mice. In parallel, a total of 40 differentially expressed genes, 6 up-regulated and 34 down-regulated, were also found in the brains from moderate 18-month-old normal mice compared to 1-month-old normal mice. Thus, differentially expressed genes upon APPsw overexpression and the aging process are useful targets through which investigators can choose genes of particular interest. In the future, it will be necessary to study the function of differentially expressed genes, which are targets for developing drugs, using pharmacoproteomics.

Oligonucleotide-based analysis of differentially expressed genes in hippocampus of transgenic mice expressing NSE-controlled APPsw.

The complexity of Alzheimer's disease (AD) has made it difficult to examine its underlying mechanisms. A gene microarray offers a solution to the complexity through parallel analysis of most of the genes expressed in the hippocampal tissues from AD-transgenic and age-matched control littermates. This study examined the potential effect of APPsw over-expression on the modulation of genes for AD. To accomplish this, an oligonucleotide array was used with the large-scale screening of the hippocampus mRNA from 12-month-old APPsw-transgenic and control mice. There was a total of 116 differentially expressed genes, 59 up-regulated and 57 down-regulated, in the hippocampal region of the transgenic mice compared with the control mice. Initially, two of each of the down-regulated (Xlr3b and Mup3) and up-regulated genes (Serpina9 and Ccr6) were chosen for further investigation if the magnitude of change in these genes on the oligonucleotide array would correspond to those in the RT-PCR analysis from APPsw-transgenic mice. We also found that the changes in the differentially expressed genes are reliable. Thus, these genes might associate with AD neuropathology in neurodegenerative process of AD, although relevance of long lists altered genes should be evaluated in a future study.

Changes in presenilin 2-binding Wnt proteins, behavior, amyloid-beta 42, gamma-secretase activity, and testosterone sensitivity in transgenic mice coexpressing tetracycline-controlled transactivator and human mutant presenilin 2.

Nonregulatable promoters have been mainly used to produce transgenic mice that express the human genes for Alzheimer's disease (AD). The aim of this study was to produce doubly transgenic mice expressing the regulatable tet promoter-controlled transactivator (tTA) and human mutant presenilin 2 (N141I, hPS2m) genes in order to examine the AD-related phenotypes at the basal and inducible levels. To achieve this, the first lineage of the transgenic line, expressing Tet/tTA and the second lineage of transgenic mice, expressing Tet/hPS2m, were created, and the doubly transgenic mice were produced by crossing the Tet/tTA-transgenic mice with the Tet/hPS2m-transgenic mice. The doubly transgenic mice and nontransgenic littermates were then treated with or without doxycycline. The results showed that removing doxycycline from the transgenic mice resulted in the induction of the transgene, a Wnt signaling defect, behavioral impairment, elevated amyloid-beta-42 and gamma-secretase activity compared with in the group given doxycyline. Moreover, the expression levels of the hPS2m transgene decreased gradually in the transgenic males, with clear changes becoming apparent between 2 and 4 wk of age. Castrating these males resulted in an increased expression level of the hPS2m gene. This was restored to the normal levels by treatment with testosterone. Therefore, tetregulated transgenic mice can be used to examine the effect of the basal or inducible expression levels of hPS2m on the pathology of AD at the "on/off" states at any stage of development.

Aging-related correlation of insulin-degrading enzyme with gamma-secretase-generated products involving insulin and glucose levels in transgenic mice.

Insulin-degrading enzyme (IDE) is a 110-kDa thiol zinc-methalloendopeptidase that can cleave small Abeta peptides and the APP intracellular domain (AICD). The aim of this study was to examine aging-related correlation of IDE with gamma-secretase-generated products involving insulin and glucose levels in transgenic brains expressing neuron-specific enolase (NSE)-controlled human mutant presenilin-2 (hPS2m). Herein, we concluded that the levels of IDE expression in transgenic brains were decreased relative to those of control mice at 15 months of age. In parallel, inhibition in the IDE expression at this age underlies to the levels-up of Abeta-42, AICD, gamma-secretase, and glucose with a level-down of insulin. Thus, IDE expression is critical target for the therapeutic trials.

Tau and GSK3beta dephosphorylations are required for regulating Pin1 phosphorylation.

Pin1 binds mitotically phosphorylated Thr231-Pro232 and Thr212-Pro213 sites on tau, and a Pin1 deficiency in mice leads to tau hyperphosphorylation. The aim of this study was to determine if the dephosphorylation or inhibition of tau and GSK3beta phosphorylation induces the Pin1 phosphorylation. To test this, human SK-N-MC cells were stably transfected with a fusion gene containing neuron-specific enolase (NSE)-controlled APPsw gene(NSE/APPsw), to induce Abeta-42. The stable transfectants were then transiently transfected with NSE/Splice, lacking human tau (NSE/Splice), or NSE/hTau, containing human tau, into the cells. The NSE/Splice- and NSE/hTau-cells were then treated with lithium. We concluded that (i) there was more C99-beta APP accumulation than C83-betaAPP in APPsw-tansfectant and thereby promoted Abeta-42 production in transfectants. (ii) the inhibition of tau and GSK3beta phosphorylations correlated with increase in Pin1 activation in NSE/hTau- cells. Thus, these observations suggest that Pin1 might have an inhibitive role in phosphorylating tau and GSK3beta for protecting against Alzheimer's disease.

Differentially expressed genes in transgenic mice carrying human mutant presenilin-2 (N141I): correlation of selenoprotein M with Alzheimer's disease.

Mutations in genes for Alzheimer's disease (AD) result in a modulating of gene expressions in the brains of patients with AD. The aim of this study was to identify genes whose expression is modulated due to the over-expression of human mutant presenilin-2 (N141I) (hPS2m) in transgenic mice, which has previously been produced by us. To test this, GeneFishing DEG101 technique was performed on large-scale screen of mRNA from transgenic and non-transgenic brains. A total of 40 transcriptional products corresponding to cDNA were compared between two brains, and 17 showed a differential expression between the samples in all sets of experiments. However, all showed significant homology to known genes. Initially, a cloning corresponding to human selenoprotein M (hSelM) was chosen for investigation further because SelM induced by sodium selenite, a pro-oxidant, may have a functional role in catalyze the free radicals. We found that mouse SelM had significantly suppressed on its transcriptional products in transgenic brains. In parallel, suppression of endogenous was not observed in transgenic brains. Moreover, the levels of green fluorescence on hSelM fusion protein with EGFP were suppressed in the cells transfected with hPS2m, and its levels had actually increased by treatments of sodium selenite. Thus, the results indicate that SelM might play a suppressive or protective role in the pathology of patients with AD and it will be necessary to investigate further on functional roles of other up- and down-regulated gene in future.

NSE-controlled carboxyl-terminus of APP gene over-expressing in transgenic mice induces altered expressions in behavior, Abeta-42, and GSK3beta binding proteins.

The amyloid protein precursor (APP) is cleaved in its intramembranous domain by gamma-secrease to generate amyloid beta and a free carboxyl-terminal intracellular fragment. The carboxyl-terminal of 105 amino acids of APP (APP-C105) plays a crucial role in the neuropathology of Alzheimer's disease (AD), but it is incompletely understand how APP-C105 overexpression interacts and regulates the brain function and Abeta-42 levels, and whether or not it is associated with the expressions of GSK3beta-binding proteins. To test this, transgenic mice expressing NSE-controlled APP-C105 were produced and tested for their above phenotypes. A behavioral deficit was observed in the 9 months old transgenic mice, and western blot indicated that there was a predominant expression of APP-C105 in transgenic brains compared with those of non-transgenic brains. In parallel, APP-C105 overexpression resulted in the modulation of the Abeta-42 level, gamma-secretase activity, GSK3beta-binding proteins including PS1, tau, and beta-catenin in the brains of the transgenic mice relative to the non-transgenic mice. Thus, altered expressions of these neuropathological phenotypes in APP-C105 transgenic mice could be useful targets in developing new therapeutic treatments.

Early changes in behavior deficits, amyloid beta-42 deposits and MAPK activation in doubly transgenic mice co-expressing NSE-controlled human mutant PS2 and APPsw.

1. Doubly transgenic mice were some differences in the period proceeding of the development of Abeta-42 deposits and behavioral deficits. It was not characterized human mutant PS2 (hPS2) with APPsw in the brains of double transgenic mice. The aim of this study was to examine whether doubly transgenic mice co-expressing NSE-controlled APPsw and hPS2m develop AD-like phenotypes much earlier than singly APPsw or hPS2m alone. 2. We produced doubly transgenic mice from a cross between our previously created NSE-controlled hPS2m and an APPsw transgenic line. This doubly transgenic line was quantitatively produced by cross with age-matched control mice, and the produced mice were separated into 5, 6, 7 and 8-month old age groups. At the age of 8 months, the four groups of mice were tested for behavioral function, levels of Abeta-42 deposition, and potential signaling events. 3. It was shown that all the AD-like phenotypes, including behavior deficits, Abeta-42 levels, MAPK activation and ER expressions in doubly transgenic mice develop much earlier in the early time of AD development than their singly transgenic and non-transgenic littermates. 4. The results suggest that elevated Abeta-42 levels, and MAPK activation in doubly transgenic mice are model for early diagnosis and treatment of AD with therapeutic drug.

cDNA microarray-based analysis of differentially expressed genes in transgenic brains expressing NSE-controlled APPsw.

cDNA microarray technique has been widely used for the detection and elucidation of differentially expressed genes on a large scale and at a speed never before possible. The aim of this study was to gain insight into the potentially overexpressed effects of APPsw on the modulation of genes for Alzheimer's disease (AD), which is central to understanding the complexity of AD. APPsw transgenic mice, which we previously produced, provide an important resource for identifying differentially expressed genes since this transgenic line was shown to have cognitive deficits along with Abeta-42 deposits at 12 months of age. To identify differentially expressed genes, cDNA microarray technique was conducted to get a large-scale screening of brain mRNA from 18 month-old NSE/APPsw transgenic and non-transgenic mice. A total of 52 differentially expressed genes, 10 up-regulated and 42 down-regulated, were found in the brains of moderately transgenic mice compared to non-transgenic littermates. Thus, the results suggest the need for future studies on gene functions, pathology, toxicogenomics, and pharmacogenomics.

An in vivo bioassay for detecting antiandrogens using humanized transgenic mice coexpressing the tetracycline-controlled transactivator and human CYP1B1 gene.

The typical strategy used in analysis of antiandrogens involves the morphological changes of a marker in castrated rats Hershberger assay for the prostate, seminal vesicle, levator ani plus bulbocavernosus muscles (LABC), Cowper's gland, and glans penis. However, there are disadvantages to this approach, such as the time required, and the results may not correspond to those in actual human exposure. To evaluate its ability for detecting antiandrogens, in vivo the dose effect of di-(2-ethylhexyl) phthalate (DEHP) and time effect of five antiandrogens, DEHP, di-n-butyl phthalate (DBP), diethyl phthalate (DEP), linuron (3-(4-dichlorophenyl)-methoxy-1-methylurea), and 2,4'-DDE (1,1-dichloro-2-(p-chlorophenyl)-2-(o-chlorophenyl)ethylene), were investigated using humanized transgenic mice coexpressing tetracycline-controlled transactivator (tTA) and the human cytochrome P450 (CYP) enzyme CYP1B1 (hCYP1B1). Adult transgenic males were treated with each of the five antiandrogens, and their tTA-driven hCYP1B1 expressions analyzed by real-time polymerase chain reaction (PCR) and/or Western blot and for O-debenzylation activity. Herein, the treatments of adult males with the five antiandrogens were shown to affect the increased levels of tTA-driven hCYP1B1 expression in both dose-dependent and repeated experiments. Thus, this novel in vivo bioassay, using humanized transgenic mice, is useful for measuring antiandrogens, and is a means to a more relevant bioassay relating to actual human exposure.

Mutant nicastrin protein can induce the cytochrome c release and the Bax expression.

This study investigated whether nicastrin can induce apoptotic cell death in SK-N-MC cells. MTT assays revealed the transfected cells expressing mutant nicastrin, compared with those expressing wild nicastrin or the control vector, showing significantly increased cell death. The mutant nicastrin transfectants were also observed to induce cytosolic cytochrome c release from the mitochondria, and Bax protein expression in response, to increased cell death. These observations suggested that nicastrin, as well as the APP and PS proteins, were also involved in the upregulated Bax mediated neuroblastoma cell death and the release of cytochrome c in the neuroblastoma.

Carboxyl-terminus of the amyloid protein precursor and ERbeta are required for estrogenic effect in activating mitogen-activated protein kinase.

Estrogen influences the processing of the amyloid beta precursor protein (APP) in the pathogenesis of Alzheimer's disease, and this effect is mediated by estrogen receptors (ERs) in activating mitogen-activated protein kinase (MAPK)-signaling pathway. To test whether the estrogenic effect on both carboxyl-terminal amino acid fragment (C-terminal) of APP (APP-C105)- and ERbeta-mediated MAPK activation in in vitro, two hybrid genes containing each human ERbeta and APP-C105 gene fused to the neuron-specific enolase (NSE) promoter were constructed and were transfected to the neuronal SK-N-MC cells. Western blot shows that the activation of JNK-signaling pathway, but not p38 and ERK, is dependent on ERbeta through estrogen treatment and APP-C105 is also mediated through estrogen in activating MAPK-signaling pathway. The results suggest that ERbeta and APP-C105 derived from APP are necessary for estrogenic effect in activating MAPK-signaling pathway.

Aberrant expressions of pathogenic phenotype in Alzheimer's diseased transgenic mice carrying NSE-controlled APPsw.

Mutations in the APP gene lead to enhanced cleavage by the beta- and gamma-secretase, and increased Abeta formation, which are tightly associated with Alzheimer's disease (AD)-like neuropathological changes. To examine whether depositions of Abeta by APP mutations are increased, and if this is associated with potential pathogenic phenotypes, the APPsw was expressed in a transgenic line under the control of the neuron-specific enolase (NSE) promoter. A behavioral dysfunction was shown at 12 months, and intensive staining bands, with APP and Abeta-42 antibodies, were visible in the brains of transgenic mice. Of the MAPK family, both JNK and p38 were activated in the brains of transgenic mice, whereas there was no significant activation of the ERK. In parallel, tau phosphorylation was also enhanced in the transgenic relative to the control mice. Moreover, the Cox-2 levels, from Western blot and immunostaining, were increased in the brains of the transgenic line. Furthermore, there were significant caspase-3- and TUNEL-stained nuclei in the transgenic line compared to the age-matched control mice. Thus, these results suggest that NSE-controlled APPsw transgenic mice appear to be a more relevant model in neuropathological phenotypes of AD, and thus could be useful in developing new therapeutic treatments for targeting the aberrant phenotypes that appear in these mice.

Use of NSE/PS2m-transgenic mice in the study of the protective effect of exercise on Alzheimer's disease.

In its late stage, Alzheimer's disease results in progressive muscle weakness in the arms and legs. The aim of this study was to determine whether mice expressing the skeletal muscle-specific mutant PS2 gene (a model of Alzheimer's disease) are a useful experimental system to study the protective effect of exercise on A beta-42 reduction, improvement of behavioural function and changes in metabolic parameters. With this aim in mind, the transgenic mice were subjected to treadmill exercise for 3 months. The results showed that in transgenic mice, but not in normal mice, treadmill exercise resulted in a reduction of A beta-42 deposits and an improvement in behavioural function, thereby restoring normal concentrations of total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and triglyceride. Thus, exercise may represent a practical therapeutic strategy for use with human patients with Alzheimer's disease.

Differential expression of proteins of caspases and Bcl-2 families in the brain of mice.

Apoptosis is an important process in the variety of different biological system including cell death and embryonic development. Inappropriate apoptosis is implicated in many human diseases such as Alzheimer's disease. Central component of the machinery of apoptosis program in neurons of patients with Alzheimer's disease includes proteins of caspases and Bcl-2 families. We examined whether endogenous protein levels of caspases and Bcl-2 families are expressed in a differential manner during the embryonic and postnatal development of BDF1 strain. Here, all four proteins with caspases-3, -9, Bcl-2 and Bax were highly expressed between embryonic day 19 and 1 week age of early postnatal development, but thereafter the expression dramatically declined. These patterns are needed to compare the proteins in the brains of APPsw-transgenic mice that are expected to be expressed highly in the brain of adult mice. Thus, the results are useful to understand fundamentally the mechanisms of the apoptotic changes during the embryonic and postnatal development of Alzheimer's model mice.

An in vitro bioassay for xenobiotics using the SXR-driven human CYP3A4/lacZ reporter gene.

The dose and time effect of nine xenobiotics, including 17beta-estradiol, corticosterone, dexamethasone, progesterone, nifedipine, bisphenol A, rifampicin, methamphetamine, and nicotine were investigated, in vitro, using human steroid and xenobiotics receptor (SXR)-binding sites on the human CYP3A4 promoter, which can enhance the linked lacZ reporter gene transcription. To test this, liver-specific SAP (human serum amyloid P component)-SXR (SAP/SXR) and human CYP3A4 promoter-regulated lacZ (hCYP3A4/lacZ) constructs were transiently transfected into HepG2 and NIH3T3 cells to compare the xenobiotic responsiveness between human and nonhuman cell lines. In the HepG2 cells, rifampicin, followed by corticosterone, nicotine, methamphetamine, and dexamethasone, exhibited enhanced levels of the lacZ transcript, whereas those of bisphenol A and nifedipine were found to be reduced. No significant responses were observed with 17beta-estradiol or progesterone. In addition, 17beta-estradiol and progesterone did not change the levels of the lacZ transcripts in the HepG2 cells, but did induce significant increases in the transcripts of the NIH3T3 cells. Treatment with corticosterone and dexamethasone, which were highly expressed in the HepG2 cells, did not affect the levels of the lacZ transcript in NIH3T3 cells. These results show that lacZ transcripts can be measured, rapidly and reproducibly, using reverse transcriptase-polymerase chain reaction (RT-PCR) based on the expression of the hCYP3A4/lacZ reporter gene, and was mediated by the SXR. Thus, this in vitro reporter gene bioassay is useful for measuring xenobiotic activities, and is a means to a better relevant bioassay, using human cells, human genes and human promoters, in order to get a closer look at actual human exposure.