Differentiation of umbilical cord mesenchymal stem cells into hepatocytes with CYP450 metabolic enzyme activity induced by a liver injury microenvironment

The aim of this study was to observe the effect of a simulated liver tissue injury microenvironment on the directed differentiation of umbilical cord mesenchymal stem cells into hepatocytes with CYP450 metabolic activity in vitro, and to explore the mechanisms underlying this directed differentiation. Normal and damaged liver tissue homogenate supernatants (LHS and CCl₄-LHS, respectively) were used as induction fluids. After induction for different durations, Western blot and RT-PCR were used to measure the protein and gene expression of the hepatocellular proteins AFP, CK18, ALB, and the CYP450 family. Simultaneously, the metabolic activity of CYP450 in hepatocytes was determined. Compared with the LHS and CCl₄-LHS controls, the LHS and CCl₄-LHS induction groups showed a significantly elevated protein and gene expression of AFP, CK18, ALB, CYP1A1/2, CYP2A6, CYP2C9, CYP2C19, CYP2D6, CYP2E1, and CYP3A4 (P < 0.05). The metabolic activity of CYP450 in hepatocytes was increased (P < 0.05). In addition, compared with the LHS group, the CCl₄-LHS group induced cell differentiation more rapidly and with a higher efficiency. The results suggested that a liver injury microenvironment is conducive for the directed differentiation of umbilical cord mesenchymal stem cells into hepatocytes with metabolic enzyme activity.

[Knobloch syndrome on multimodal imaging: a case report]

A 12-year-old boy presented to the hospital because of poor vision for half a year. Examination revealed nystagmus in both eyes. Examination of the anterior segment of both eyes showed no obvious abnormalities, and the vitreous bodies of both eyes were concentrated and agglutinated. Fundus showed clear boundary of optic disc, pale white, leopard striated retina, and characteristic atrophy of pigment epithelium, choroid, and macular atrophy. Knobloch syndrome was confirmed by multimodal imaging and genetic testing.

A crystal plasticity model for metal matrix composites considering thermal mismatch stress induced dislocations and twins

Originated at heterogeneous interfaces with distinct coefficient of thermal expansion (CTE), thermal mismatch stress is one of the critical influential factors to mechanical properties of metal matrix composites (MMCs). This stress is normally accommodated plastically by various defects, for example, high-density dislocations and twins in Al near heterogeneous interfaces in SiC/Al composites. Basic knowledge on the influence of defect characteristics is important but difficult to extrapolate from experimental results. However, existed theoretical models more focus on the influence of dislocation density, but less focus on defects variety, volume and distribution. In this paper, we propose a physics-based crystal plasticity model that has the capability of dealing with thermal mismatch stress induced dislocations and twins (denoted as TMDT model). The proposed TMDT model that is implemented in the Visco-Plastic Self-Consistent (VPSC) method considers defect heterogeneous distribution (gradient range), defect type (dislocations vs. twins) and defect volume fraction (twin spacing vs. twin volume). We demonstrate the validity and the capability of the VPSC-TMDT model in SiC/Al composites with thermal mismatch induced dislocations or twins. Furthermore, this model predicts the ultra-high strength of Graphene/Copper composites with high-density nanoscale twins, which is in turn the future aim for such nanocomposites.

Effects of progesterone on glucose uptake in neurons of Alzheimer's disease animals and cell models

AIMS

Alzheimer's disease (AD) is closely related to abnormal glucose metabolism in the central nervous system. Progesterone has been shown to have obvious neuroprotective effects in the pathogenesis of AD, but the specific mechanism has not been fully elucidated. Therefore, the purpose of this study was to investigate the effect of progesterone on the glucose metabolism of neurons in amyloid precursor protein (APP)/presenilin 1 (PS1) mice and Aβ-induced AD cell model.

MATERIALS AND METHODS

APP/PS1 mice were treated with 40 mg/kg progesterone for 40 days and primary cultured cortical neurons were treated with 1 μM progesterone for 48 h.Then behavior tests,2-NBDG glucose uptake tests and the protein levels of glucose transporter 3 (GLUT3), GLUT4, cAMP-response element binding protein (CREB) and proliferator-activated receptor γ (PPARγ) were examined.

KEY FINDINGS

Progesterone increased the expression levels of GLUT3 and GLUT4 in the cortex of APP/PS1 mice, accompanied by an improvement in learning and memory. Progesterone increased the levels of CREB and PPARγ in the cerebral cortex of APP/PS1 mice. In vitro, progesterone increased glucose uptake in primary cultured cortical neurons, this effect was blocked by the progesterone receptor membrane component 1 (PGRMC1)-specific blocker AG205 but not by the progesterone receptor (PR)-specific blocker RU486. Meanwhile, progesterone increased the expression of GLUT3, GLUT4, CREB and PPARγ, and AG205 blocked this effect.

SIGNIFICANCE

These results confirm that progesterone significantly improves the glucose metabolism of neurons.One of the mechanisms of this effect is that progesterone upregulates protein expression of GLUT3 and GLUT4 through pathways PGRMC1/CREB/GLUT3 and PGRMC1/PPARγ/GLUT4.

Overexpression of SIRT6 in the hippocampal CA1 impairs the formation of long-term contextual fear memory

Histone modifications have been implicated in learning and memory. Our previous transcriptome data showed that expression of sirtuins 6 (SIRT6), a member of Histone deacetylases (HDACs) family in the hippocampal cornu ammonis 1 (CA1) was decreased after contextual fear conditioning. However, the role of SIRT6 in the formation of memory is still elusive. In the present study, we found that contextual fear conditioning inhibited translational expression of SIRT6 in the CA1. Microinfusion of lentiviral vector-expressing SIRT6 into theCA1 region selectively enhanced the expression of SIRT6 and impaired the formation of long-term contextual fear memory without affecting short-term fear memory. The overexpression of SIRT6 in the CA1 had no effect on anxiety-like behaviors or locomotor activity. Also, we also found that SIRT6 overexpression significantly inhibited the expression of insulin-like factor 2 (IGF2) and amounts of proteins and/or phosphoproteins (e.g. Akt, pAkt, mTOR and p-mTOR) related to the IGF2 signal pathway in the CA1. These results demonstrate that the overexpression of SIRT6 in the CA1 impaired the formation of long-term fear memory, and SIRT6 in the CA1 may negatively modulate the formation of contextual fear memory via inhibiting the IGF signaling pathway.

Establishment of a rat model of thioacetamide induced hepatic fibrosis

AIM: To establish a stable and efficient rat model of thioacetamide (TAA) induced hepatic fibrosis.

METHODS: Male SD rats were randomly divided into a normal group and a model group. The model group was intragastrically administrated 3% TAA at 160 mg/kg body weight and the normal group was administrated distilled water. Serum and hepatic tissue samples were collected after 6 wk. Serum levels of ammonia (BAM), alkaline phosphatase (AKP), total bilirubin (TBIL), albumin/globulin (ALB/GLB) and cell factors including hepatocyte growth factor (HGF), heparin-binding epidermal growth factor (HB-EGF), interleukin-6 (IL-6), and α-smooth muscle antibody (α-SMA) were detected. Histopathological examination of liver tissue was conducted by HE staining and Masson staining, and the degree of liver fibrosis was observed under a microscope. The natural repair of hepatic fibrosis was observed by HE staining 11 wk after stopping administration of TAA.

RESULTS: The rate of hepatic fibrosis was 100% after intragastric administration of TAA for 6 wk. Compared with the control group, the liver function in the model group changed significantly; serum levels of BAM, AKP and TBIL increased significantly, and the ratio of ALB/GLB decreased significantly (P < 0.01). Serum levels of HGF and HB-EGF decreased significantly, and serum IL-6 and α-SMA increased significantly (P < 0.01). The degree of hepatic fibrosis was not changed until 11 weeks after stopping TAA.

CONCLUSION: A stable and persistent rat model of hepatic fibrosis has been successfully prepared by intragastric administration of TAA for 6 wk. This is a convenient and practical method to establish a rat liver fibrosis model with a high rate of hepatic fibrosis formation.

A novel splice site mutation in the dentin sialophosphoprotein gene in a Chinese family with dentinogenesis imperfecta type II

Twenty-four individuals were investigated that spanned six generations in a Chinese family affected with an apparently autosomal dominant form of dentinogenesis imperfecta type II (DGI-II, OMIM #125490). All affected individuals presented with typical, clinical and radiographic features of DGI-II, but without bilateral progressive high-frequency sensorineural hearing loss. To investigate the mutated molecule, a positional candidate approach was used to determine the mutated gene in this family. Genomic DNA was obtained from 24 affected individuals, 18 unaffected relatives of the family and 50 controls. Haplotype analysis was performed using leukocyte DNA for 6 short tandem repeat (STR) markers present in chromosome 4 (D4S1534, GATA62A11, DSPP, DMP1, SPP1 and D4S1563). In the critical region between D4S1534 and DMP1, the dentin sialophosphoprotein (DSPP) gene (OMIM *125485) was considered as the strongest candidate gene. The first four exons and exon/intron boundaries of the gene were analyzed using DNA from 24 affected individuals and 18 unaffected relatives of the same family. DNA sequencing revealed a heterozygous deletion mutation in intron 2 (at positions -3 to -25), which resulted in a frameshift mutation, that changed the acceptor site sequence from CAG to AAG (IVS2-3C-->A) and may also have disrupted the branch point consensus sequence in intron 2. The mutation was found in the 24 affected individuals, but not in the 18 unaffected relatives and 50 controls. The deletion was identified by allele-specific sequencing and denaturing high-performance liquid chromatography (DHPLC) analysis. We conclude that the heterozygous deletion mutation contributed to the pathogenesis of DGI-II.

Effects of morphine dependence and withdrawal on levels of neurosteroids in rat brain

AIM

To investigate the effects of morphine dependence and withdrawal on the concentrations of neurosteroids in rat brain.

METHODS

A method of simultaneous quantification of neurosteroids by gas chromatography-mass spectrometry (GC-MS) had been established.

RESULTS

The chronic morphine administration (ip) resulted in a marked decrease in the brain concentrations of pregnenolone (PREG), progesterone (PROG), and pregenenolone sulfate (PREGS) in rats killed 6 h after the last treatment. In contrast, there were no significant effects of morphine dependence on the brain concentrations of allopregnanolone (AP), dihydroepiandrosterone (DHEA), and dihydroepiandrosterone sulfate (DHEAS). Naloxone-induced withdrawal produced a significant increase in the concentrations of PREG, PROG, AP, DHEA, PREGS, and DHEAS as compared with the control group.

CONCLUSION

Morphine dependence and withdrawal affected the concentrations of neurosteroids in rat brain, which suggests that endogenous neurosteroids in brain might be related to the development of morphine dependence and withdrawal.

Stereoselectivity in trans-tramadol metabolism and trans-O-demethyltramadol formation in rat liver microsomes

AIM

To study the stereoselectivity in trans-tramadol [(+/-)-trans-T] metabolism and trans-O-demethyltramadol (M1) formation.

METHODS

(+)-, (-)-, Or (+/-)-trans-T was separately incubated with rat liver microsomes in vitro. The concentrations of (+/-)-trans-T and M1 enantiomers were determined by high performance capillary electrophoresis (HPCE).

RESULTS

When each enantiomer of (+/-)-trans-T was incubated with rat liver microsomes, the metabolic rate of (+)-trans-T was lower than that of (-)-trans-T. The kinetics of (+)-, (-)-M1 formation was found to fit the single-enzyme Michaelis-Menten model. The Vmax and CLint of (+)-M1 formation were lower than those of (-)-M1 formation. When (+/-)-trans-T was used as the substrate, the metabolic rates of (+)-, (-)-trans-T, and the formation rates of (+)-M1, (-)-M1 decreased to different extents. Dextromethorphan (Dex), propafenone (Pro), and fluoxetine (Flu) could inhibit both the metabolism of (+/-)-trans-T enantiomers and the formation of M1 enantiomers. Pro and Flu were shown to enhance the stereoselectivity in both (+/-)-trans-T metabolism and M1 formation, and Dex could only enhance that in M1 formation.

CONCLUSION

(+/-)-Trans-T metabolism and M1 formation were stereoselective, (-)-trans-T being preferentially metabolized and (-)-M1 being preferentially formed. There was interaction in metabolism between (+/-)-trans-T enantiomers. Dex, Pro, and Flu had different effects on the stereoselectivity.

Stereoselectivity in renal clearance of trans-tramadol and its active metabolite, trans-O-demethyltramadol

AIM

To study the stereoselectivity in renal clearance of trans-tramadol and its active metabolite, trans-O-demethyltramadol.

METHODS

The right kidneys were isolated from male SD rats and perfused with 100 mL of perfusate medium containing trans-tramadol 300 microg/L or trans-O-demethyltramadol 50 microg/L. After perfusion, the concentrations of the enantiomers of trans-tramadol and trans-O-demethyltramadol in the perfusate and urine were determined by high performance capillary electrophoresis. The enantiomeric ratios were calculated.

RESULTS

After the kidneys being perfused with trans-tramadol hydrochloride, the concentration of (+)-trans-tramadol was higher than that of (-)-trans-tramadol, and the concentration of (+)-trans-O-demethyltramadol was lower than that of (-)-trans-O-demethyltramadol in the perfusate; meanwhile, (+)-trans-tramadol was more than (-)-trans-tramadol, and (+)-trans-O-demethyltramadol was less than (-)-trans-O-demethyltramadol in the urine. After the kidneys being perfused with trans-O-demethyltramadol, the concentration of (+)-trans- O-demethyltramadol was lower than that of (-)-trans-O-demethyltramadol in the perfusate, and (+)-trans-O-demethyltramadol was more than (-)-trans-O-demethyltramadol in the urine.

CONCLUSION

The renal clearance of trans-tramadol was stereoselective. The O-demethylation of trans-tramadol was stereoselective in the kidneys, (-)-trans-tramadol being preferentially metabolized. The renal clearance of trans-O-demethyltramadol was also stereoselective, the (+)-enantiomer being preferentially cleared into the urine.

Distribution of enantiomers of trans-tramadol and trans-O-demethyltramadol in central nervous system of rats

AIM

To investigate the distribution of the enantiomers of trans-tramadol (trans-T) and its active metabolite, trans-O-demethyltramadol (M1), in the central nervous system (CNS).

METHODS

After a single ip dose of trans-T hydrochloride or M1, the rats were killed by decapitation. A high performance capillary electrophoresis (HPCE) method was used to determine the concentrations of enantiomers of trans-T and M1 in the serum and different brain tissues, including cerebrospinal fluid (CF), cerebral cortex (CC), corpus striatum (CS), hypothalamus (HY), cerebellum (CE), and medulla oblongata (MO).

RESULTS

After ip trans-T hydrochloride, the concentrations of (+)-trans-T were higher than those of (-)-trans-T in the serum and all tested brain tissues; The concentrations of (+)-M1 were lower than those of (-)-M1 in the all tested brain tissues; The concentrations of the enantiomers of trans-T and M1 were the highest in the CC, the lowest in the CF. After ip M1, the concentrations of (+)-M1 were higher than those of (-)-M1 in the serum and all tested brain tissues; The concentrations of the enantiomers of M1 were the highest in the CC, the lowest in the CF.

CONCLUSION

The concentrations of the enantiomers of trans-T and M1 varied in the serum and different brain tissues. The distribution of trans-T and M1 in the CNS of rats was stereoselective. The stereoselectivity in the distribution of M1 after M1 injection was different with that after trans-T injection.

[Transportation of the enantiomers of trans tramadol and O-demethyltramadol across blood-brain barrier]

AIM

To investigate the transportation of the enantiomers of trans tramadol (trans T) and its active metabolite, O-demethyltramadol (M1) across blood-brain barrier.

METHODS

Rats were sacrificed by femoral artery bleeding 1 h after i.p. administration of trans T hydrochloride, 16.7 mg.kg-1 or 50.0 mg.kg-1. Blood, cerebrospinal fluid and cerebral cortex were taken out. The enantiomers of trans T and M1 were analyzed by high performance capillary electrophoresis (HPCE).

RESULTS

Among the three tissues, the concentration of each enantiomer of trans T and M1 was the highest in the cerebral cortex, and the lowest in the cerebrospinal fluid. In the serum, the concentration of (+)-trans T was higher than that of (-)-trans T, and the concentrations of the enantiomers of M1 were similar. In the cerebrospinal fluid and cerebral cortex, the concentration of (+)-trans T was higher than that of (-)-trans T, and the concentrations of (+)-M1 was lower than that of (-)-M1.

CONCLUSION

The transportation across blood-brain barrier of the enantiomers of trans T and M1 was stereoselective. In the brain tissues, the concentrations of (+)-trans T and (-)-M1 were higher than those of their enantiomers.

[Effect of stilbene polymer (Gn-3) on experimental liver injuries in mice]

AIM

To study the protective effect of Gn-3 (a stilbene polymer isolated from Gnetum parvifolium) against liver injury induced by CCl4, N-acetyl-p-aminophenol (APAP) and Bacillus Calmette-Guerin (BCG) plus bacterial lipopolysaccharide (LPS) in mice.

METHODS

The experimental model of liver injury were induced by 0.1% CCl4 i.p. (10 mL.kg-1.d-1 for 3d), APAP i.p. (150 mg.kg-1) or BCG (5 mg) plus LPS (7.5 micrograms) in mice. The levels of ALT in serum, MDA and GSH in liver tissues were detected. The histopathologic changes were observed by light microscope.

RESULTS

Gn-3 was shown to markedly reduce the elevated serum ALT levels, liver tissue MDA and improve the histopathological changes in all the three experimental liver injury models. No effect of Gn-3 was observed on the liver GSH level in liver injury mice.

CONCLUSION

Gn-3 was found to inhibit the development of liver injury caused by CCl4, APAP, or BCG plus LPS. This means that Gn-3 has liver protective effects.

Pharmacokinetics of enantiomers of trans-tramadol and its active metabolite, trans-O-demethyltramadol, in human subjects

AIM

To study the stereoselectivity in pharmacokinetics of the enantiomers of trans-tramadol (trans-T) and its active metabolite, trans-O-demethyltramadol (M1) in human subjects.

METHODS

Trans-T hydrochloride sustained-release tablets were taken orally by 12 healthy male volunteers. After a multiple dosage schedule, the serum concentrations of (+)-trans-T, (-)-trans-T, (+)-M1, and (-)-M1 were determined in serum by high performance capillary electrophoresis (HPCE).

RESULTS

(+)-Trans-T, (-)-trans-T, (+)-M1 and (-)-M1 in human serum were separated by HPCE. The linear range was 2.5-320 microg/L for the enantiomers of trans-T, and 2.5-50 microg/L for the enantiomers of M1. For the enantiomers of trans-T and M1, the intra-day and inter-day RSD were less than 15 % and 20 %, and the relative recoveries were 94.3 %-106.2 % and 90.4 %-107.8 %, respectively; the limit of quantitation was 1.25 microg/L. The serum concentrations of the enantiomers of trans-T reached a steady state in 12 subjects on d 4 after the initial administration. The steady state serum concentrations of (+)-trans-T were higher than that of (-)-trans-T at every sampling points in the subjects. The differences were significant in the main pharmacokinetic parameters between (+)-trans-T and (-)-trans-T except Tmax. The serum concentrations of (-)-M1 were higher than that of (+)-M1 in most subjects and at most sampling time points. There were significant differences in Cmax and Cmin between the enantiomers of M1.

CONCLUSION

The pharmacokinetics of trans-T and M1 was found to be stereoselective. (+)-Trans-T was shown to be absorbed completely, but eliminated more slowly. The pharmacokinetic stereoselectivity of M1 was different among human subjects.

[Effects of baicalin on liver microsomal cytochrome P450 system]

AIM

To investigate the effect of baicalin on liver microsomal cytochrome P450 system and the mechanism of liver protective action of baicalin.

METHODS

Liver microsomal cytochrome P450, b5, aminopyrin N-demethylase (ADM), 7-ethoxycoumarin O-deethylase (ECD) and benzopyrene hydroxylase (AHH) activity were quantitated by UV chromatography. Activities of six cytochrome P450 isoforms were assayed with Western Blotting.

RESULTS

Baicalin increased liver microsomal cytochrome. P450 level and ADM, ECD and AHH activity significantly. The three P450 isoforms, 1A1, 2B1 and 2C11, were also induced selectively by baicalin, but the b5 level, 3A2, 2D1 and 2E1 were not induced.

CONCLUSION

Baicalin increases liver microsomal cytochrome P450 level and induces selectively 1A1, 2B1 and 2C11 of P450 isoforms in mice.

[Determination of acemetacin and indometacin in human serum by high performance liquid chromatography]

A method of HPLC for the quantitative determination of acemetacin and indometacin in human serum is described. After being extracted with diethyl ether, acemetacin and indometacin were analyzed by reversed-phase HPLC(Spherisorb-C8) and UV-detector(254 nm), with tolbutamide as internal standard. The mobile phase was a mixture of V(acetate buffer solution, pH 4.6):V(methyl alcohol):V(acetonitrile) = 55:5:40 and at a rate of 1.0 mL/min. Over the mass concentration range of 12.5 micrograms/L-1.6 mg/L, both the calibration curves were linear, r = 0.9996, n = 8. The average recoveries of acemetacin and indometacin were 77.2% and 86.7% respectively. The within-day and between-day RSD of acemetacin and indometacin were less than 5% and 10% respectively.

The induction of liver microsomal cytochrome P450 by Glycyrrhiza uralensis and glycyrrhetinic acid in mice

The effect of Glycyrrhiza uralensis Fisch (GRZ) aqueous extract and one of its active principles Glycyrrhetinic acid (GRT) on hepatic cytochrome P450 in mice were investigated. Oral administration of GRZ at 10 g/kg/d or GRT at 50 mg/kg/d for 7 days was found to increase the P450 contents up to 4.6 fold compared with the controls. The activities of aryl hydrocarbon hydroxylase (AHH, 3.1 and 3.3 fold), aminopyrine N-demethylase (ADM, 4.2 and 3.2 folds), and 7-ethoxycumarin O-deethylase (ECOD, 2.8 and 2.5 fold) were also shown to be increased. Western blot analysis showed that the subtypes of P450 isoforms induced selectively by GRZ and GRT included CYP1A1 (1.8 and 1.5 fold over that of the control, respectively), CYP2B1 (both 1.3 fold), and CYP2C11 (3.2 and 3.0 fold). Moreover, significant positive correlation between the P450 content or the isoforms and the corresponding enzyme activities mentioned above was observed.

Characterization of NMDA- and AMPA-induced enhancement of AP-1 DNA binding activity in rat cerebellar granule cells

Effects of the glutamate receptor agonists, N-methyl-D-aspartate (NMDA) and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), on the activator protein-1 (AP-1) DNA binding activity were studied in primary cultures of rat cerebellar granule cells. Application of NMDA as well as of AMPA produced a concentration-dependent enhancement of AP-1 binding. Further examination revealed that only a brief exposure (10 min) to NMDA or AMPA was required for the initiation of a significant, four- to sixfold enhancement of AP-1 DNA binding activity. Blockade of the desensitization of AMPA receptors by cyclothiazide further reduced the exposure time needed to activate the AP-1 complex. The time needed to achieve a maximal increase of AP-1 binding activity varied depending on the glutamate receptor agonist used. NMDA gave maximal AP-1 stimulation after 60 min exposure, whereas stimulation with AMPA alone reached a maximum after 240 min exposure. When AMPA was applied together with cyclothiazide the maximal enhancement of AP-1 binding was reached much faster, within 120 min. Supershift analysis with specific antibodies against the members of Fos and Jun protein families (c-Fos, Fos B, c-Jun, Jun B, Jun D) revealed that the NMDA-induced AP-1 complex was composed predominantly of Jun D and c-Fos. The composition of the AP-1 complex activated by AMPA alone was similar to that produced by NMDA, but with an additional contribution of Fos B. In contrast, application of AMPA plus cyclothiazide induced an AP-1 transcription with contribution of Jun D, c-Fos, Fos B, c-Jun and Jun B proteins. These findings indicate that glutamate is able to enhance AP-1 DNA binding activity in cerebellar granule cells through both NMDA and AMPA glutamate receptors.

Chronic ethanol enhances NMDA-induced AP-1 activity in cultured rat cerebellar granule cells

We examined the effects of chronic ethanol exposure (50 mM; 3 days) on N-methyl-D-aspartate (NMDA)- and alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)-induced AP-1 transcription factor DNA binding activity in primary cultures of rat cerebellar granule cells. Chronic ethanol exposure enhanced NMDA-stimulated AP-1 binding activity, with no corresponding change in AMPA-stimulated AP-1 binding. Supershift analysis with specific antibodies against the members of Fos and Jun protein families showed that the NMDA-induced AP-1 protein complex consisted predominantly of c-Fos and Jun D proteins. Chronic ethanol treatment by itself did not change the protein composition of the AP-1 complex.

N-Methyl-D-aspartate-induced enhancement of activator protein-1 DNA binding activity is blocked by ethanol in cerebellar granule cells

The effects of ethanol on N-methyl-D-aspartate (NMDA) and non-NMDA receptor agonist-stimulated activator protein-1 (AP-1) DNA binding activity in primary cultures of rat cerebellar granule cells were investigated. The application of intoxicating concentrations of ethanol produced a concentration-dependent inhibition of NMDA-enhanced AP-1 binding with a significant reduction obtained at 50 mM ethanol. The inhibitory actions of ethanol on alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)-stimulated AP-1 binding were considerably weaker as compared to the effects seen following administration of NMDA. The AMPA-induced enhancement of AP-1 DNA binding activity was demonstrated both in the absence and presence of cyclothiazide, a drug, which is known to block the desensitization of AMPA receptors. Our data suggest that moderate concentrations of ethanol modulate glutamate-induced alterations of gene expression in brain neurons.

A mu-receptor opioid agonist induces AP-1 and NF-kappa B transcription factor activity in primary cultures of rat cortical neurons

Activator protein 1 (AP-1) and nuclear factor kappa B (NF-kappa B) represent mammalian transcription factors which bind to distinct enhancer motifs. The specific mu-receptor opioid agonist, Tyr, D-Ala2, Gly, N-Me-Phe4, Gly-ol5 (DAMGO), was found to increase AP-1 and NF-kappa B activity in primary cultures of neurons from rat cerebral cortex. Acute (2 h, 4 h) and long-term (72 h) treatment with DAMGO time-dependently increased the DNA-binding activity of both AP-1 and NF-kappa B and the stimulation could be abolished or inhibited by concurrent incubation with naloxone. However, acute naloxone-precipitated withdrawal did not significantly change AP-1 or NF-kappa B activity. These results indicate a mu-opioid receptor-related co-induction of AP-1 and NF-kappa B transcription factors in cultured cortical neurons.