G-quadruplexes are guanine-rich nucleic acid sequences capable of forming a four-stranded structure through Hoogsteen hydrogen bonding. G-quadruplexes are highly concentrated near promoters and transcription start sites suggesting a role in gene regulation. They are less often found on the template than non-template strand where they either inhibit or enhance transcription, respectively. However, their potential role in enhancers and other distal regulatory elements has not been assessed yet. Here we show that DNAse hypersensitive (DHS) cis-regulatory elements are also enriched in Gs and their G-content correlate with that of their respective promoters. Besides local G4s, the distal cis regions may form G-quadruplexes together with the promoters, each contributing half a G4. This model is supported more for the non-template strand and we hypothesised that the G4 forming capability of the promoter and the enhancer non-template strand could facilitate their binding together and making the DHS regions accessible for the transcription factory.

• MeSH
• biologické modely MeSH
• G-kvadruplexy * MeSH
• guanin MeSH
• lidé MeSH
• promotorové oblasti (genetika) * MeSH
• regulační oblasti nukleových kyselin MeSH
• transkripční faktory metabolismus   MeSH
• vazba proteinů MeSH
• vazebná místa MeSH
• zastoupení bazí MeSH
• zesilovače transkripce * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

GATA-1 and PU.1 are two important hematopoietic transcription factors that mutually inhibit each other in progenitor cells to guide entrance into the erythroid or myeloid lineage, respectively. PU.1 controls its own expression during myelopoiesis by binding to the distal URE enhancer, whose deletion leads to acute myeloid leukemia (AML). We herein present evidence that GATA-1 binds to the PU.1 gene and inhibits its expression in human AML-erythroleukemias (EL). Furthermore, GATA-1 together with DNA methyl Transferase I (DNMT1) mediate repression of the PU.1 gene through the URE. Repression of the PU.1 gene involves both DNA methylation at the URE and its histone H3 lysine-K9 methylation and deacetylation as well as the H3K27 methylation at additional DNA elements and the promoter. The GATA-1-mediated inhibition of PU.1 gene transcription in human AML-EL mediated through the URE represents important mechanism that contributes to PU.1 downregulation and leukemogenesis that is sensitive to DNA demethylation therapy.

• MeSH
• akutní erytroblastická leukemie genetika   patologie   MeSH
• akutní myeloidní leukemie genetika   patologie   MeSH
• buněčná diferenciace genetika   MeSH
• DNA-(cytosin-5-)methyltransferasa genetika   metabolismus   MeSH
• genetická transkripce MeSH
• histony genetika   MeSH
• lidé MeSH
• metylace DNA genetika   MeSH
• promotorové oblasti (genetika) MeSH
• protoonkogenní proteiny biosyntéza   genetika   metabolismus   MeSH
• regulace genové exprese u leukemie MeSH
• trans-aktivátory biosyntéza   genetika   metabolismus   MeSH
• transkripční faktor GATA1 genetika   metabolismus   MeSH
• vazba proteinů MeSH
• zesilovače transkripce MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Cadherins and protocadherins are cell adhesion proteins that play an important role in neuronal migration, differentiation and synaptogenesis, properties that make them targets to consider in schizophrenia (SZ) and bipolar disorder (BD) pathogenesis. Consequently, allelic variation occurring in protocadherin and cadherin encoding genes that map to regions of the genome targeted in SZ and BD linkage studies are particularly strong candidates to consider. One such set of candidate genes is the 5q31-linked PCDH family, which consists of more than 50 exons encoding three related, though distinct family members--alpha, beta, and gamma--which can generate thousands of different protocadherin proteins through alternative promoter usage and cis-alternative splicing. In this study, we focused on a SNP, rs31745, which is located in a putative PCDHalpha enhancer mapped by ChIP-chip using antibodies to covalently modified histone H3. A striking increase in homozygotes for the minor allele at this locus was detected in patients with BD. Molecular analysis revealed that the SNP causes allele-specific changes in binding to a brain protein. The findings suggest that the 5q31-linked PCDH locus should be more thoroughly considered as a disease-susceptibility locus in psychiatric disorders.

• MeSH
• lidé MeSH
• Check Tag
• lidé MeSH

Many enhancers control gene expression by assembling regulatory factor clusters, also referred to as condensates. This process is vital for facilitating enhancer communication and establishing cellular identity. However, how DNA sequence and transcription factor (TF) binding instruct the formation of high regulatory factor environments remains poorly understood. Here we developed a new approach leveraging enhancer-centric chromatin accessibility quantitative trait loci (caQTLs) to nominate regulatory factor clusters genome-wide. By analyzing TF-binding signatures within the context of caQTLs and comparing episomal versus endogenous enhancer activities, we discovered a class of regulators, 'context-only' TFs, that amplify the activity of cell type-specific caQTL-binding TFs, that is, 'context-initiator' TFs. Similar to super-enhancers, enhancers enriched for context-only TF-binding sites display high coactivator binding and sensitivity to bromodomain-inhibiting molecules. We further show that binding sites for context-only and context-initiator TFs underlie enhancer coordination, providing a mechanistic rationale for how a loose TF syntax confers regulatory specificity.

• MeSH
• chromatin * genetika   metabolismus   MeSH
• lidé MeSH
• lokus kvantitativního znaku * MeSH
• myši MeSH
• regulace genové exprese MeSH
• transkripční faktory * metabolismus   genetika   MeSH
• vazba proteinů MeSH
• vazebná místa genetika   MeSH
• zesilovače transkripce * MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Donepezil je novým kognitivem, jehož mechanizmus účinku spočívá v reverzibilní a specifické inhibici acetylcholinesterázy. Dávka 5, respektive 10 mg donepezilu blokovala acetylcholinesterázu v erytrocytech (úzká korelace s působením v CNS) z 64, respektive 75 %. Dalšími účinky donepezilu jsou nepřímá stimulace muskarinových a nikotinových receptorů zvýšenou koncentrací acetylcholinu v synapsích CNS, zvýšení extraneuronální koncentrace nejen acetylcholinu, ale i noradrenalinu a případně dopaminu, snížení průniku kyslíkových radikálů membránami neuronů a zlepšení metabolizmu glukózy v CNS. Vstřebávání donepezilu z gastrointestinálního traktu je úplné a není ovlivněno jídlem. Lék dosahuje maximální plazmatické koncentrace za 3-5 hodin po použití a z 95 % se nízkoafinitně váže na krevní bílkoviny. Vylučovací poločas donepezilu činí 70-80 ;hodin a stabilizované sérové koncentrace je dosaženo za 14-21 dnů léčby. Donepezil se vyznačuje lineární farmakokinetikou. Jeho metabolit 6-O-desmetyl-donepezil je biologicky aktivní. Průkaz terapeutické účinnosti donepezilu se opírá o 4 placebem kontrolované studie, ve kterých bylo léčeno celkem 1 920 nemocných s lehkou až středně těžkou Alzheimerovou demencí po dobu 12-26 týdnů. Od 3.-12. týdne léčby došlo ke zlepšení kognitivních a ;behaviorálních funkcí u cca 21-38 % léčených a ke stabilizaci stavu u dalších 20-45 % nemocných, což také znamená terapeutický úspěch u tak progresivní poruchy, jakou je Alzheimerova demence. Zlepšení psychického stavu nastalo především u ;lehčích demencí, zatímco u středně těžkých forem došlo jen ke stabilizaci příznaků. Po vysazení donepezilu nastala opětná pozvolná deteriorace stavu, což ukazuje, že toto nové kognitivum neléčí příčinu Alzheimerovy demence. V otevřeném prodloužení těchto studií byl donepezil podáván 133 nemocným až po dobu 2 let a další studie probíhají. Počáteční zlepšení výchozích hodnot kognitivních a behaviorálních funkcí trvalo 26-38 týdnů a poté následovala postupná deteriorace psychického stavu. Donepezil dokázal symptomaticky vrátit a stabilizovat biologické životní hodiny nemocných o 6-12 měsíců, takže došlo k průkaznému zpomalení průběhu Alzheimerovy demence oproti neléčeným nemocným. Provedené studie prokázaly, že minimální účinnou dávkou je 5 mg donepezilu, kterou pro dlouhý vylučovací poločas postačuje podávat jednou denně. Dávka 10 mg/den byla v některých studiích a parametrech účinnější než nižší dávkování. Donepezil byl nemocnými velmi dobře tolerován. U 5-20 % léčených se z nežádoucích příznaků nejčastěji vyskytly nauzea, průjem, vomitus, svalové křeče, únava a insomnie. Zvýšenou opatrnost doporučuje výrobce při podávání nemocným s peptickým vředem, průduškovým astmatem a poruchami srdečního převodu. Při intoxikaci je antidotem atropin.

Donepezil is a new cognitive enhancer whose mechanism of action consists in reversible specific inhibition of acetyl-cholinesterase activity. The doses of 5 and 10 mg of donepezil had the effect of blocking acetylcholinesterase in erythrocytes (correlating closely with its effect in the CNS) in 64 and 75 % respectively. Other effects of donepezil include indirect stimulation of muscarine and nicotine receptors by increasing the concentration of acetylcholine in CNS synapses, increasing the extraneuronal concentration not only of acetylcholine, but also of noradrenaline and eventually dopamine, decreasing the permeability of oxygen radicals through neurone membranes, and improving the glucose metabolism in CNS. The absorption of donepezil from the gastrointestinal tract is complete and remains unaffected by food intake. The maximum plasmatic concentration of the preparation is reached within 3 to 5 hours after administration; the drug binds with low affinity to plasma proteins. The elimination half-life of donepezil is 70 to 80 hours, the steady state serum concentration being reached within 14 to 21 days of treatment. Donepezil is characterised by linear pharmacokinetics. Its metabolite 6-O-desmethyl-donepezil is biologically active. The proof of therapeutic efficacy of donepezil is based on 4 placebo-controlled clinical studies which included the total of 1920 patients with the diagnosis of Alzheimer’s disease of mild to medium severity, treated for 12 to 26 weeks. From the 3rd to 12th week on, in approx. 21 to 38% of patients an improvement of cognitive and behavioural functions was observed. In 20 to 45% of patients stabilisation of state occurred, which also can be interpreted as therapeutic success in dealing with a disorder of such progression as Alzheimer’s disease. Psychic state improvement was observed especially in milder dementia, while in patients suffering from the disease of medium severity only stabilisation of symptoms was observed. The discontinuation of donepezil administration was followed by a slow state deterioration, which shows that the drug does not treat the cause of Alzheimer’s disease. In an open continuation of these studies donepezil was administered to 133 patients for intervals of up to 2 years. There are other studies which have not yet been finished. The initial improvement of starting values of cognitive and behavioural functions lasted from 26 to 38 weeks, being followed by gradual deterioration of psychic state. Donepezil had the capacity to stabilise symptomatically and rewind the biological life of the patients back by 6 to 12 months and thus to slow down the course of Alzheimer’s disease in comparison with untreated patients. The conducted studies have shown that the minimum efficient dose of donepezil is 5 mg (administered once a day thanks to its long elimination half-life). In some studies the dose of 10 mg per day was found to be more efficient than the lower dose. Donepezil was very well tolerated by patients. Adverse effects observed in 5 to 20% of patients most often included nausea, diarrhoea, vomiting, muscle cramps, fatigue, and insomnia. The producer recommends careful administration especially to patients suffering from peptic ulcers, bronchial asthma and cordial conduction disorders. In cases of intoxication atropine is the antidote.

• MeSH
• acetylcholinesterasa MeSH
• Alzheimerova nemoc farmakoterapie   MeSH
• cholinesterasové inhibitory MeSH
• donepezil MeSH
• léčivé přípravky kontraindikace   MeSH
• lidé MeSH
• nežádoucí účinky léčiv MeSH
• psychotropní léky aplikace a dávkování   farmakokinetika   farmakologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• klinické zkoušky MeSH
• přehledy MeSH

Galantamin je dualisticky působící kognitivum nové generace. Mechanizmus účinku spočívá v inhibici acetylcholinesterázy a alosterické modulaci nikotinových receptorů. Kromě zvýšení koncentrace acetylcholinu dochází v neuronálních synapsích k uvolnění i dalších neurotransmiterů, neuroprotektivního prekurzoru amyloidního proteinu (APP) a expresi některých genů ve vztahu k nikotinovému receptoru. V 7 kontrolovaných studiích galantamin ovlivnil úspěšněji než placebo kognitivní a nekognitivní příznaky Alzheimerovy demence a terapeutický účinek přetrvával nejméně 1 rok. Při delším podávání bylo pozorováno zpomalení progrese choroby. Slibným je i pro terapii nonrespondérů k donepezilu a rivastigminu pro odlišný farmakologický profil. V kontrolované studii galantamin úspěšně léčil i smíšenou a vaskulární demenci. Jeho nevýhodou je nutnost počáteční titrace, podávání 2x denně a možné interakce s inhibitory P4502D6 a 3A4 a dalšími obdobně působícími léky.

Galantamine is a dual action cognitive enhancer of a new generation. Its mechanism of effect consists in the inhibition of acetylcholinesterase and alosteric modulation of nicotine receptors. Besides increasing the concentration of acetylcholine, galantamine causes the release of other neurotransmitters, the neuroprotective amyloid protein precursor (APP) and gene expression in neuronal synapses. In 7 controlled studies, galantamine was more effective than placebo in influencing both cognitive and non-cognitive symptoms (BPSD) of the Alzheimer's dementia while its therapeutic effect lasted for at least one year. It delayed the progression of the disease during the long-term administration. Due to its different pharmacological profile, galantamine also seems promising in the treatment of donepezil and rivastigmine non-responders. It proved successful even in treating mixed and vascular dementia in a controlled study. Its drawbacks are the slow initial titration, administration twice per day and possible interactions with P4502D6 and 3A4 inhibitors and other drugs with a similar mechanism of action.

• MeSH
• alkaloidy aplikace a dávkování   farmakokinetika   farmakologie   MeSH
• Alzheimerova nemoc terapie   MeSH
• biomedicínský výzkum MeSH
• galantamin MeSH
• lidé MeSH
• Check Tag
• lidé MeSH

A growing number of long non-coding RNAs (lncRNAs) have been linked to squamous cell carcinoma of the head and neck (SCCHN). A subclass of lncRNAs, termed enhancer RNAs (eRNAs), are derived from enhancer regions and could contribute to enhancer function. In this study, we developed an integrated data analysis approach to identify key eRNAs in SCCHN. Tissue-specific enhancer-derived RNAs and their regulated genes previously predicted using the computational pipeline PreSTIGE, were considered as putative eRNA-target pairs. The interactive web servers, TANRIC (the Atlas of Noncoding RNAs in Cancer) and cBioPortal, were used to explore the RNA levels and clinical data from the Cancer Genome Atlas (TCGA) project. Requiring that key eRNAs should show significant associations with overall survival (Kaplan⁻Meier log-rank test, p < 0.05) and the predicted target (correlation coefficient r > 0.4, p < 0.001), we identified five key eRNA candidates. The most significant survival-associated eRNA was AP001056.1 with ICOSLG encoding an immune checkpoint protein as its regulated target. Another 1640 genes also showed significant correlation with AP001056.1 (r > 0.4, p < 0.001), with the "immune system process" being the most significantly enriched biological process (adjusted p < 0.001). Our results suggest that AP001056.1 is a key immune-related eRNA in SCCHN with a positive impact on clinical outcome.

• Publikační typ
• časopisecké články MeSH

Rivastigmin je reverzibilním nekompetitivním inhibitorem acetylcholinesterázy II. generace, který tlumí její aktivitu selektivně v určitých částech CNS vůči periferii a podstatně méně blokuje butyrylcholinesterázu. Rivastigmin rovněž stimuluje aktivitu cholinacetyltransferázy, zvyšující syntézu acetylcholinu. Ve zvířecích pokusech rivastigmin zlepšoval paměť a učení po lézích předního mozku či po anticholinergicích stejně jako upravoval důsledky ischemie či zavřeného traumatu mozku. Léčebná účinnost rivastigminu byla prokázána 3 klinickými studiemi v délce trvání 26 týdnů. U celkem 2 126 léčených byl rivastigmin v denních dávkách 6-12 mg i 1-4 mg účinnější než placebo. Pokud ke zlepšeným (22-30 %) jsou připočítáni i stabilizovaní pacienti, pak byla terapie rivastigminem úspěšná u 51 % léčených. Nástup účinku byl pozorován mezi 12.-18. týdnem pozorování. Předběžné výsledky otevřených dlouhodobých 1-2 ročních studií ukázaly, že zlepšení psychického stavu trvalo cca 38 týdnů a poté následovala postupná progrese demence, která byla zpomalena ve 2. roce léčby rivastigminem. Rivastigmin byl velmi dobře snášen. Nejčastějšími nežádoucími účinky byly gastrointestinální obtíže, závratě, cefalgie, únava, somnolence nebo insomnie a agitovanost, ponejvíce v úvodní titrační fázi léčby. Rivastigmin je zatížen minimálním rizikem interakcí s jinými léky. Při těžší intoxikaci je antidotem atropin.

Rivastigmine is a reversible and noncompetitive acetylcholinesterase inhibitor of the second generation, selectively inhibiting its activity in the certain brain areas in comparison with the peripheries. Rivastigmine also enhances cholinacetyltransferase activity, which stimulates acetylcholine synthesis. In animal trials, rivastigmine enhanced memory and learning after forebrain lesions and after the administration of anticholinergic drugs. It also improved the consequences of ischemia or closed head injury. The therapeutic efficacy of rivastigmine has been proven by three 26-weeks lasting clinical trials. In the total of 2126 patients, rivastigmine in dosages both of 6-12 mg and 1-4 mg has been more effective than placebo. If we include into the group of improved patients (22-30 %) also those whose state was stabilized, then the rivastigmine therapy is successful in 51 % of patients. The onset of the therapeutic effect was observed between the 12th and 18th weeks of the trial. The preliminary results of long-term (1-2 year) studies inform us that the psychic state improvement lasted for approximately 38 weeks, followed by a gradual deterioration of dementia that was slowed down in the second year of treatment. Rivastigmine was very well tolerated. The most frequent adverse effects included gastrointestinal complaints, vertigo, headache, somnolence or insomnia and agitation, frequent in the initial titration phase of the treatment. The risk of drug interactions of rivastigmine was minimum. Atropine is the antidote in a serious intoxication.

• MeSH
• acetylcholinesterasa MeSH
• cholinesterasové inhibitory farmakologie   chemie   MeSH
• demence farmakoterapie   MeSH
• klinické hodnocení nového léčiva MeSH
• lidé MeSH
• neurobehaviorální symptomy účinky léků   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• klinické zkoušky, fáze II MeSH
• srovnávací studie MeSH

The CCAAT/enhancer-binding protein alpha, encoded by the intronless CEBPA gene, is a transcription factor that induces expression of genes involved in differentiation of granulocytes, monocytes, adipocytes and hepatocytes. Both mono- and bi-allelic CEBPA mutations were detected in acute myeloid leukaemia and myelodysplastic syndrome. In this study we also identified CEBPA mutations in healthy individuals and in patients with peripheral artery disease, ischaemic heart disease and hyperlipidaemia. We found 16 various deletions with the presence of two direct repeats in CEBPA by analysis of 431 individuals. Three most frequent repeats included in these deletions in CEBPA gene are CGCGAG (493- 498_865-870), GG (486-487_885-886), and GCCAAGCAGC (508-517_907-916), all according to GenBank Accession No. NM_004364.2. In one case we identified that a father with ischaemic heart disease and his healthy son had two identical deletions (493_864del and 508_906del, both according to GenBank Accession No. NM_004364.2) in CEBPA. The occurrence of deletions between two repetitive sequences may be caused by recombination events in the repair process. A double-stranded cut in DNA may initiate these recombination events in adjacent DNA sequences. Four types of polymorphisms in the CEBPA gene were also detected in the screened individuals. Polymorphism in CEBPA gene 690 G>T according to GenBank Accession No. NM_004364.2 is the most frequent type in our analysis. Statistical analysis did not find significant differences in the frequency of polymorphisms in CEBPA in patients and in healthy individuals with the exception of P4 polymorphism (580_585dup according to GenBank Accesion No. NM_004364.2). P4 polymorphism was significantly increased in ischaemic heart disease patients.

• MeSH
• financování organizované MeSH
• hyperlipidemie genetika   MeSH
• ischemická choroba srdeční genetika   MeSH
• lidé MeSH
• molekulární sekvence - údaje MeSH
• mutace MeSH
• mutační analýza DNA MeSH
• onemocnění periferních cév genetika   MeSH
• polymorfismus genetický MeSH
• protein alfa vázající zesilovač transkripce CCAAT genetika   metabolismus   MeSH
• sekvence aminokyselin MeSH
• sekvence nukleotidů MeSH
• Check Tag
• lidé MeSH

Enhancers play a central role in the spatiotemporal control of gene expression and tend to work in a cell-type-specific manner. In addition, they are suggested to be major contributors to phenotypic variation, evolution and disease. There is growing evidence that enhancer dysfunction due to genetic, structural or epigenetic mechanisms contributes to a broad range of human diseases referred to as enhanceropathies. Such mechanisms often underlie the susceptibility to common diseases, but can also play a direct causal role in cancer or Mendelian diseases. Despite the recent gain of insights into enhancer biology and function, we still have a limited ability to predict how enhancer dysfunction impacts gene expression. Here we discuss the major challenges that need to be overcome when studying the role of enhancers in disease etiology and highlight opportunities and directions for future studies, aiming to disentangle the molecular basis of enhanceropathies.

• MeSH
• epigeneze genetická * MeSH
• lidé MeSH
• zesilovače transkripce * genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH