Molecular basis of hypohidrotic ectodermal dysplasia: an update.

Recent advances in understanding the molecular events underlying hypohidrotic ectodermal dysplasia (HED) caused by mutations of the genes encoding proteins of the tumor necrosis factor α (TNFα)-related signaling pathway have been presented. These proteins are involved in signal transduction from ectoderm to mesenchyme during development of the fetus and are indispensable for the differentiation of ectoderm-derived structures such as eccrine sweat glands, teeth, hair, skin, and/or nails. Novel data were reviewed and discussed on the structure and functions of the components of TNFα-related signaling pathway, the consequences of mutations of the genes encoding these proteins, and the prospect for further investigations, which might elucidate the origin of HED.

[Hormone-sensitive lipase/cholesteryl esterase from the adrenal cortex - structure, regulation and role in steroid hormone synthesis]. / Hormonozalezna lipaza/esteraza cholesterolowa z kory nadnerczy - struktura, regulacja i rola w syntezie hormonów steroidowych.

Hormone-sensitive lipase/cholesteryl esterase (HSL), encoded by LIPE gene, plays a very important role in the metabolism of acylglycerols in the adipose tissue and cholesteryl esters in the adrenal cortex, gonads and placenta. Isoforms of this enzyme supply fatty acids, important energy substrates, and free cholesterol required for steroid hormone synthesis. Recent discoveries on hormonal regulation of HSL synthesis with special emphasis given to the regulation of LIPE gene expression, its tissue-specific promoters and activation of the gene products by phosphorylation, as well as the role of HSL in the metabolism of cholesteryl esters were reviewed. In the concluding remarks, the gaps in our knowledge of the metabolism of acylglyceroles and cholesteryl esters, as well as the possibility of effects, synergic with HSL, influencing metabolism of these compounds were discussed.

Novel insertion in exon 5 of the TCOF1 gene in twin sisters with Treacher Collins syndrome.

Treacher Collins syndrome (TCS) is associated with an abnormal differentiation of the first and second pharyngeal arches during fetal development. This causes mostly craniofacial deformities, which require numerous corrective surgeries. TCS is an autosomal dominant disorder and it occurs in the general population at a frequency of 1 in 50,000 live births. The syndrome is caused by mutations in the TCOF1 gene, which encodes the serine/alanine-rich protein named Treacle. Over 120 mutations of the TCOF1 gene responsible for TCS have been described. About 70% of recognized mutations are deletions, which lead to a frame shift, formation of a termination codon, and shortening of the protein product of the gene. Herewith, a new heterozygotic insertion, c.484_668ins185bp, was described in two monozygotic twin sisters suffering from TCS. This mutation was absent in their father, brother, and uncle, indicating a de novo origin. The insertion causes a shift in the reading frame and premature termination of translation at 167 aa. The novel insertion is the longest ever found in the TCOF1 gene and the only one found among monozygotic twin sisters.

Accumulation of environmental estrogens in adipose tissue of breast cancer patients.

Although the estrogenic properties of numerous chloroorganic pesticides have been widely recognized, population studies do not give clear results indicating the link between the exposure to these compounds and breast cancer development. Because of the weak affinity of these pesticides to estrogen receptors, they probably act by affecting the expression of CYP genes encoding cytochromes P450 engaged in the metabolism of environmental as well as natural estrogens. To examine the possible correlation between environmental estrogen levels in adipose tissue and breast cancer stage, grade, receptor status and onset of the disease, adipose tissue was isolated from 54 breast cancer patients and 23 healthy individuals. Clinical characteristics were obtained from the medical records, while the information concerning exposure to environmental estrogens where obtained from questionnaires. The environmental estrogens were identified and quantified by GC-chromatography. The data was analyzed with the use of Student t-test and Spearman correlation. The levels of most environmental estrogens did not differ between the patients and the controls, except the beta-HCH (beta-hexachlorocyclohexane) level, which was higher in the patients than in the healthy individuals. Significantly higher levels of DDE (1,1-bis(4-chlorophenyl)-2,2-dichloroethene) and DDT (1,1,1-trichloro-2,2-bis(4-chlorophenol)ethane) (P < 0.05) were observed in the patients with late onset of the disease which was probably due to the time of exposure. Moreover, in the patients exposed to environmental estrogens, significantly higher concentrations of DDD (1,1-bis(4-chlorophenyl)-2,2-dichloroethane) were found (P < 0.05). We also evidenced that estrogen-independent cancer was more frequent in the patients exposed to numerous risk factors in which higher levels of HCB (hexachlorobenzene), gamma-HCH (gamma-hexachlorocyclohexane), DDD and DDT in adipose tissue were detected. Breast cancer development is probably related to the accumulation of DDT and its derivatives, but the effect appears only in older patients. We postulate that environmental estrogens acting together with other risk factors might influence the progress and exacerbate the prognosis of breast cancer.

TGF-beta inhibits CYP17 transcription in H295R cells acting via activin receptor-like kinase 5.

OBJECTIVE: Transforming growth factor beta (TGF-beta) is a potent inhibitor of 17alpha-hydroxylase/17,20 lyase activity and CYP17 gene expression. We investigated the mechanism how CYP17 is inhibited by TGF-beta in adrenocortical cells. METHODS: H295R cells were culture and incubated with TGF-beta, transcription inhibitor (DRB), activin receptor-like kinase 5 ALK5 (TbetaRII) inhibitor (SB431542), mitogen activated kinases inhibitors (PD98059 and SB203580), subsequently using reverse transcription and quantitative PCR (RT-qPCR) we determined CYP17 expression. RESULTS: TGF-beta significantly decreased the level of cytochrome P450c17 mRNA and this inhibitory effect of TGF-beta on CYP17 expression required activin receptor-like kinase 5 (ALK5) and on-going transcription. Mitogen activated kinases MEK1 and p38 MAPK are not involved it the inhibitory effect of TGF-beta on CYP17 expression. CONCLUSION: We concluded that the TGF-beta-dependent decrease of 17alpha-hydroxylase/17,20 lyase activity in the H295R cells is caused by inhibition of CYP17 transcription and is mediated by the ALK5 receptor.

The 1674+11C>T polymorphism of CHRNA4 is associated with juvenile myoclonic epilepsy.

The alpha4 subunit gene (CHRNA4) of the neuronal nicotinic acetylcholine receptor (nAChR), linked to an idiopathic partial epilepsy, autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE), may also play a key role in the development of the idiopathic generalized epilepsy syndrome (IGE), juvenile myoclonic epilepsy (JME). This study was designed to explore an association of four polymorphisms of the CHRNA4 with JME in Polish children and young patients. The study included 92 JME patients and 222 unrelated healthy individuals. In each group the frequencies of the CHRNA4 c.555C>T, c.594C>T, 1674(+11)C>T, and 1674(+14)A>G polymorphisms were determined using PCR-RFLP analyses. An association between the 1674(+11)C>T polymorphism of the CHRNA4 and JME was evidenced. Allele T (the risk factor) appeared with a significantly higher frequency in the JME patients than in the controls (p=0.0299). The patients harboring the 1674(+11)CT+TT genotypes showed an increased risk of JME (CT+TT versus CC: OR=1.925; 95% CI=1.021-3.629; p=0.0408). No association was found for the other CHRNA4 polymorphisms tested. The CHRNA4 1674(+11)C>T polymorphism may be a susceptibility factor for epilepsy, and its higher frequency in patients with juvenile myoclonic epilepsy suggests that the CHRNA4 may be one of the candidate genes for this epileptic syndrome.

Studies on CYP1A1, CYP1B1 and CYP3A4 gene polymorphisms in breast cancer patients.

BACKGROUND: The role of CYP1A1, CYP1B1 and CYP3A4 polymorphism in pathogenesis of breast cancer has not been fully elucidated. From three CYP1A1 polymorphisms *2A (3801T>C), *2C (2455A>G), and *2B variant, which harbors both polymorphisms, the *2A variant is potentially carcinogenic in African Americans and the Taiwanese, but not in Caucasians, and the CYP1B1*2 (355G>T) and CYP1B1*3 (4326C>G) variants might increase breast cancer risk. Although no association of any CYP3A4 polymorphisms and breast cancer has been documented, the CYP3A4*1B (392A>G) variant, correlates with earlier menarche and endometrial cancer secondary to tamoxifen therapy. OBJECTIVE: The present study was designed to investigate the frequency of CYP1A1, CYP1B1 and CYP3A4 polymorphisms in a sample of breast cancer patients from the Polish population and to correlate the results with the clinical and laboratory findings. MATERIAL AND METHODS: The frequencies of CYP1A1*2A; CYP1A1*2C; CYP1B1*3; CYP3A4*1B CYP3A4*2 polymorphisms were determined in 71 patients aged 36-87, with primary breast cancer and 100 healthy individuals. Genomic DNA was extracted from the tumor and individual gene fragments were PCR-amplified. The polymorphisms were determined by RFLP and were correlated with the patients' TNM stage, grade, estrogen and progesterone receptor status as well as the level of c-erbB-2 protein. RESULTS: CYP1A1 polymorphisms were more frequent in younger patients and in the patients with high level of c-erbB-2 protein. No correlation between these polymorphisms and the cancer stage or grade, as well as the receptor status was demonstrated. CONCLUSIONS: CYP1A1 polymorphisms probably predispose to an earlier onset of breast cancer and might be associated with higher c-erbB-2 protein level, but further studies on a much larger group are required to substantiate our findings.

Occurrence rate and genotype distribution of the JC virus (JCV) in a sample from the Polish population.

The JC virus (JCV) is a common human virus persisting in renal tissue. In immunocompromised individuals it may reactivate and cause progressive multifocal leukoencephalopathy (PML). JCV has also been implicated in cancerogenesis, leading to various brain tumors and cancers of gastrointestinal tract. In this study the JCV excretion in urine of 113 healthy Polish donors was analyzed. A 215-bp region of the viral gene coding for a major capsid protein VP1 was PCR-amplified and detected in 52 individuals (46.0%). The occurrence rate increased with age and was highest in the group of over 60-year-old donors (63.6%). Sequence analysis of the VP1 gene fragment revealed the following distribution of JCV genotypes in the investigated group: 1A, 31 (59.6%); 1B, 13 (25.0%); 2A, 2 (3.8%); and 2C, 6 samples (11.5%). The frequency and distribution of the JCV genotypes in the Polish population resembles that in other European countries, with the most abundant genotype 1 (84.6%). However, while in those countries the second most frequent genotype was usually 4, in the investigated group genotype 4 was not detected.

SMAD3 inhibits SF-1-dependent activation of the CYP17 promoter in H295R cells.

Cytochrome P450c17, encoded by the CYP17 gene, is a component of 17alpha-hydroxylase/17,20 lyase which catalyses 17alpha-hydroxylation of pregnenolone or progesterone, required for glucocorticosteroid and androgen synthesis. It has been reported that transforming growth factor beta (TGF-beta) decreases both basal and cAMP-stimulated levels of CYP17 mRNA, but the mechanism of TGF-beta action on CYP17 expression remains unknown. We investigated an inhibitory effect of TGF-beta on CYP17 expression in H295R cells using constructs containing the CYP17 promoter region fused with the luciferase gene. In the H295R cells, TGF-beta decreased endogenous SF-1 level and inhibited activity of the 300 bp fragment of CYP17 promoter, which was stimulated by coexpression of SF-1. Overexpression of SMAD3 caused an inhibition of SF-1-stimulated CYP17 promoter activity, whereas overexpression of SMAD7 was ineffective. In conclusion, our results suggest that the inhibitory action of TGF-beta on CYP17 transcription involve at least two mechanisms: SMAD3 dependent inactivation of CYP17 promoter activity and repression of SF-1 expression.

Oxidative DNA damage and level of thiols as related to polymorphisms of MTHFR, MTR, MTHFD1 in Alzheimer's and Parkinson's diseases.

Neurodegenerative diseases, such as Alzheimer's disease (AD) and Parkinson's disease (PD), are accompanied by increased levels of 8-oxo-2'-deoxyguanosine (8-oxo2dG) and alterations in levels of homocysteine (Hcy), methionine (Met), and cysteine (Cys). Hcy may undergo remethylation due to involvement of MTHFR, MTR and MTHFD1 proteins. Present studies are aimed at determination of 8-oxo2dG, Hcy, Met, and Cys in AD and PD patients as well as in control groups, using HPLC/EC/UV, as well as estimation, by restriction analysis, frequency of following gene polymorphisms: MTHFR (C677T, A1298C, G1793A), MTHFD1 (G1958A), and MTR (A2756G). In AD there were significant differences of the levels of only Cys (GG, MTHFR, G1793A) and Met/Hcy (AA, MTHFD1, G1958A) whereas in PD there were more significant differences of the levels of thiols: Hcy [MTHFR: CT (C677T) and GG (G1793A); MTR, AG (A2756G)], Met [MTR, AA (A2756G)], Cys [MTR, AG (A2756G)], and Met/Hcy [MTHFR: CC, CT (C677T) and AA (A1298C), and GG (G1793A); MTHFD1 AA(G1958A); MTR AA(A2756G)]. Significant differences in the levels of Cys/Hcy, MTHFD1 GA (G1958) were varied between AD and PD groups. The results indicate that of the enzymes studied only polymorphisms of folate-dependent enzyme MTHFD1 have pointed to significant differences in intensity of turnover of circulating thiols between AD and PD patients.

The effect of indole-3-carbinol on the expression of CYP1A1, CYP1B1 and AhR genes and proliferation of MCF-7 cells.

The influence of an antiestrogen, indole-3-carbinol (I3C) on the expression of CYP1A1, CYP1B1 and AhR genes was investigated in an attempt to establish whether I3C could increase the expression of genes involved in estrone metabolism. Another purpose was to examine the proliferation of an estrogen-dependent breast cancer cell (MCF-7 line) under the influence of I3C and both I3C and DDT. In MCF-7 cells incubated with I3C or I3C and DDT combined, quantitative RT-PCR analysis revealed a significant increase in the level of CYP1A1, AhR, and CYP1B1 transcripts. The proliferation rate of MCF-7 cells was increased by treatment with DDT or estradiol (E2), whereas I3C did not affect the proliferation of MCF-7 cells but greatly reduced the stimulatory effect of DDT, and abolished the effect of E2. The level of p21 transcript, encoding p21 protein involved in the cell cycle, was increased several-fold by I3C comparing to its level in cells incubated with estradiol or DDT. The results suggest that the proliferation of MCF-7 cells is accompanied not only by expression of genes encoding cytochromes involved in estrogen metabolism, but also by changes in the expression of other genes including that encoding p21 protein involved in the cell cycle.

Arginine vasopressin stimulates 11beta-hydroxysteroid dehydrogenase type 2 expression in the mineralocorticosteroid target cells.

11Beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2) deficiency causes sodium retention and severe hypertension by allowing glucocorticoids access to the non-selective mineralocorticosteroid receptor. Understanding regulation of the HSD11B2 gene is thus of fundamental importance in hypertension research. A number of studies have suggested that second messenger pathways may be important in this regard. In the present study we show that HSD11B2 expression in human renal epithelial P58 cells is regulated at the mRNA and protein level, and that protein kinases A (PKA) and C (PKC) are involved in this process. PKA stimulation resulted in almost two-fold increase while PKC activation in almost two-fold decrease in the HSD11B2 mRNA and protein level. Western blot analysis revealed a dimeric form of 11beta-HSD2 of about 80kDa. Arginine vasopressin (AVP), acting through the AVP2 receptor, as well as 11beta-HSD2 substrates, corticosterone and dexamethasone, up-regulate HSD11B2 expression, suggesting their role as possible factors affecting blood pressure. We show that the activators of the PKA pathway induce, while activators of PKC pathway repress the expression of HSD11B2 in human renal epithelial cells. AVP, acting via the PKA pathway, might be a physiological stimulator of the HSD11B2 expression. The 11beta-HSD2 substrates, both natural (corticosterone) and synthetic (dexamethasone), might protect the mineralocorticosteroid-target cells against cortisol excess.

A mutation c.C2812T in the androgen receptor gene resulting in Pro817Leu substitution may affect dimerization of the androgen receptor and result in androgen insensitivity syndrome.

OBJECTIVE: To conduct clinical, genetic, and molecular diagnostics of two sisters with typical symptoms of complete androgen insensitivity syndrome. DESIGN: Case report. SETTING: Research laboratory at a university of medical science. PATIENT(S): Two patients with 46,XY karyotype and a female phenotype were diagnosed because of primary amenorrhea. Their sister with 46,XX karyotype, her daughter, and five other family members including their mother also were examined. INTERVENTION(S): Orchiectomy, estrogen substitution therapy. MAIN OUTCOME MEASURE(S): Cancer prophylaxis. RESULT(S): Multiple-temperature single-stranded conformation polymorphism and sequence analyses of the androgen receptor gene (AR) revealed a c.C2812T transition in exon 7 in the two sisters. Their mother and the third sister (46,XX) were carriers of the same mutation. This mutation, which previously had never been reported, resulted in Pro817Leu substitution in the ligand-binding domain of the androgen. Computer simulation of structural changes generated by Pro817Leu substitution revealed appreciable conformational changes in the region responsible for dimerization of the receptor. CONCLUSION(S): The novel c.C2812T transition that might impair dimerization of the receptor is responsible for the clinical symptoms of complete androgen insensitivity syndrome in the affected individuals. Molecular analysis of AR proved to be very useful for genetic counseling of the unaffected sister, who was a carrier of the same mutation.

A novel c.581C>T transition localized in a highly conserved homeobox sequence of MSX1: is it responsible for oligodontia?

Even though selective tooth agenesis is the most common developmental anomaly of human dentition, its genetic background still remains poorly understood. To date, familial as well as sporadic forms of both hypodontia and oligodontia have been associated with mutations or polymorphisms of MSX1, PAX9, AXIN2 and TGFa, whose protein products play a crucial role in odontogenesis. In the present report we described a novel mutation of MSX1, which might be responsible for the lack of 14 permanent teeth in our proband. However, this c.581C>T transition, localized in a highly conserved homeobox sequence of MSX1, was identified also in 2 healthy individuals from the proband's family. Our finding suggests that this transition might be the first described mutation of MSX1 that might be responsible for oligodontia and showing incomplete penetrance. It may also support the view that this common anomaly of human dentition might be an oligogenic trait caused by simultaneous mutations of different genes.

Screening of chromosomal region 21q22.3 for mutations in genes associated with neuronal Ca2+ signalling in bipolar affective disorder.

The therapeutic effect of lithium in bipolar affective disorder may be connected with decreasing intracellular Ca(2+) concentrations. Several linkage studies have identified a potential bipolar affective disorder susceptibility locus within chromosomal region 21q22.3. This locus contains two genes expressed in the brain - ADARB1 and TRPM2 - involved in regulating intracellular Ca(2+) concentrations. The aim of this study was an identification of mutations in the coding sequences of ADARB1 and TRPM2 and their association with bipolar affective disorder. For that purpose we screened 60 patients with bipolar affective disorder and a control group of 66 subjects using single strand conformation polymorphism and sequence analysis. For rapid screening we performed restriction fragment length polymorphism analysis. Screening of bipolar affective disorder patients for mutations in TRPM2 led to identification of three novel and four known transitions. Two transitions resulted in the substitutions: R755C and A890V. Screening of the coding sequence of ADARB1 did not reveal any mutations except one already known transition. A comparison of the transition frequency in patients and controls does not support association of the detected mutations with bipolar affective disorder. According to our results, bipolar affective disorder may not be caused by mutations in ADARB1. However, this study does not exclude TRPM2 as a candidate gene since we have screened only about 30 per cent of the entire coding sequence of this large gene.

Mutations within protein kinase R-binding domain of NS5A protein of hepatitis C virus (HCV) and specificity of HCV antibodies in pretreatment sera of HCV-chronically infected patients and their effect on the result of treatment.

We analyzed protein kinase R (PKR)-binding domain sequences of hepatitis C virus (HCV) NS5A protein and the profile of HCV-specific antibodies from pretreatment sera of HCV-chronically infected patients. Results were compared with clinical data to verify their influence on the course and result of therapy. Of 9 patients enrolled in a 12-month treatment with pegylated interferon alpha (PEG-IFN-alpha) plus ribavirin (RBV), 6 patients responded to therapy, as assessed by the lack of HCV RNA in their sera, and 3 did not. Among 8 HCV-1b-infected patients, those who responded did not have significantly more mutations in the IFN sensitivity determining region (ISDR) compared to non-responders (P = 0.637). Similarly, in the remaining 26-amino acid region of the PKR-binding domain, behind ISDR, the number of mutations did not differ significantly between the two groups (P = 0.796). A correlation was found between the presence of envelope 2 (E2)-specific antibodies and the result of treatment (P = 0.048). This pilot study indicates that mutations in the PKR-binding domain of HCV genotype 1b do not correlate with outcome of PEG-IFN-alpha/RBV therapy. However, the presence of E2-specific antibodies in the pretreatment sera of HCV-chronically infected individuals could serve as a prognostic marker predicting the result of treatment, before its initiation.

Natural selection and molecular evolution in primate PAX9 gene, a major determinant of tooth development.

Large differences in relation to dental size, number, and morphology among and within modern human populations and between modern humans and other primate species have been observed. Molecular studies have demonstrated that tooth development is under strict genetic control, but, the genetic basis of primate tooth variation remains unknown. The PAX9 gene, which codes for a paired domain-containing transcription factor that plays an essential role in the development of mammal dentition, has been associated with selective tooth agenesis in humans and mice, which mainly involves the posterior teeth. To determine whether this gene is polymorphic in humans, we sequenced approximately 2.1 kb of the entire four-exon region (exons 1, 2, 3 and 4; 1,026 bp) and exon-intron (1.1 kb) boundaries of 86 individuals sampled from Asian, European, and Native American populations. We provided evidence that human PAX9 polymorphisms are limited to exon 3 only and furnished details about the distribution of a mutation there in 350 Polish subjects. To investigate the pattern of selective pressure on exon 3, we sequenced ortholog regions of this exon in four species of New World monkeys and one gorilla. In addition, orthologous sequences of PAX9 available in public databases were also analyzed. Although several differences were identified between humans and other species, our findings support the view that strong purifying selection is acting on PAX9. New World and Old World primate lineages may, however, have different degrees of restriction for changes in this DNA region.

A novel mutation in PAX9 causes familial form of molar oligodontia.

PAX9 is a paired domain transcription factor that plays a critical role in odontogenesis. All mutations of PAX9 identified to date have been associated with nonsyndromic form of tooth agenesis. The present report describes an unusual novel mutation in PAX9 identified in a family with severe molar oligodontia. This heterozygous deletion combined with 24 bp insertion (including a 5' splice site) is localized in the second exon beyond the highly conserved paired box sequence, and might result either in a premature termination of translation at aa 210 or in an aberrant splicing, leading to a frameshift and premature termination of translation at aa 314. Real-time PCR analysis revealed no mutated transcript in cultured lymphocytes of one of the affected individuals indicating that the novel mutation might result in rapid degradation of the mutated transcript leading to haploinsufficiency of PAX9. Our results support the view that mutations in PAX9 constitute a causative factor in nonsyndromic oligodontia.

Polymorphisms of the CHRNA4 gene encoding the alpha4 subunit of nicotinic acetylcholine receptor as related to the oxidative DNA damage and the level of apoptotic proteins in lymphocytes of the patients with Alzheimer's disease.

The study aimed at the analysis of polymorphisms in the gene coding for the nicotinic acetylcholine receptor alpha4 subunit (CHRNA4) and the evaluation of the extent of the oxidative damage to DNA (8-oxo2dG), as well as the level of proteins participating in DNA repair (p53, PARP) and DNA degradation (Bax:Bcl-2, 85-kDa fragment) in the peripheral blood lymphocytes of the patients suffering from Alzheimer's disease (AD) and in the healthy individuals of the control group. In the AD patients the increased levels of oxidized guanine were demonstrated in DNA, accompanied by the elevated expression of p53, Bax, PARP, and of a 85-kDa protein subunit as well as an augmented ratio of Bax:Bcl-2. Also, the level of Bcl-2 protein was decreased. In the AD patients with the CHRNA4 polymorphisms the highest level of 8-oxo2dG and of proteins involved in DNA repair were documented in patients with polymorphisms in exon 5, in contrast to the patients with polymorphisms in intron 5. In the former patients, levels of pro- and antiapoptotic proteins remained at the same level. Both CHRNA4 polymorphisms and the extent of dementia seem to affect the levels of DNA oxidative damage as well as to activate factors that participate in the DNA degradation and its repair.