BACKGROUND: Epitranscriptomics, the study of RNA modifications such as N6-methyladenosine (m6A), provides a novel layer of gene expression regulation with implications for numerous biological processes, including cellular adaptation to hypoxia. Hypoxia-inducible factor-1 (HIF-1), a master regulator of the cellular response to low oxygen, plays a critical role in adaptive and pathological processes, including cancer, ischemic heart disease, and metabolic disorders. Recent discoveries accent the dynamic interplay between m6A modifications and HIF-1 signaling, revealing a complex bidirectional regulatory network. While the roles of other RNA modifications in HIF-1 regulation remain largely unexplored, emerging evidence suggests their potential significance. MAIN BODY: This review examines the reciprocal regulation between HIF-1 and epitranscriptomic machinery, including m6A writers, readers, and erasers. HIF-1 modulates the expression of key m6A components, while its own mRNA is regulated by m6A modifications, positioning HIF-1 as both a regulator and a target in this system. This interaction enhances our understanding of cellular hypoxic responses and opens avenues for clinical applications in treating conditions like cancer and ischemic heart disease. Promising progress has been made in developing selective inhibitors targeting the m6A-HIF-1 regulatory axis. However, challenges such as off-target effects and the complexity of RNA modification dynamics remain significant barriers to clinical translation. CONCLUSION: The intricate interplay between m6A and HIF-1 highlights the critical role of epitranscriptomics in hypoxia-driven processes. Further research into these regulatory networks could drive therapeutic innovation in cancer, ischemic heart disease, and other hypoxia-related conditions. Overcoming challenges in specificity and off-target effects will be essential for realizing the potential of these emerging therapies.

• MeSH
• adenosin analogy a deriváty   metabolismus   MeSH
• epigeneze genetická * MeSH
• faktor 1 indukovatelný hypoxií * metabolismus   genetika   MeSH
• lidé MeSH
• posttranskripční úpravy RNA MeSH
• regulace genové exprese MeSH
• signální transdukce MeSH
• transkriptom MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

The precise and unambiguous detection and quantification of internal RNA modifications represents a critical step for understanding their physiological functions. The methods of direct RNA sequencing are quickly developing allowing for the precise location of internal RNA marks. This detection is, however, not quantitative and still presents detection limits. One of the biggest remaining challenges in the field is still the detection and quantification of m6A, m6Am, inosine, and m1A modifications of adenosine. The second intriguing and timely question remaining to be addressed is the extent to which individual marks are coregulated or potentially can affect each other. Here, we present a methodological approach to detect and quantify several key mRNA modifications in human total RNA and in mRNA, which is difficult to purify away from contaminating tRNA. We show that the adenosine demethylase FTO primarily targets m6Am marks in noncoding RNAs in HEK293T cells. Surprisingly, we observe little effect of FTO or ALKBH5 depletion on the m6A mRNA levels. Interestingly, the upregulation of ALKBH5 is accompanied by an increase in inosine level in overall mRNA.

• MeSH
• adenosin * analogy a deriváty   metabolismus   genetika   analýza   MeSH
• alfa-ketoglutarát-dependentní dioxygenasa, AlkB homolog 5 * metabolismus   genetika   MeSH
• chromatografie kapalinová metody   MeSH
• gen pro FTO * metabolismus   genetika   MeSH
• HEK293 buňky MeSH
• inosin * metabolismus   genetika   MeSH
• kapalinová chromatografie-hmotnostní spektrometrie MeSH
• lidé MeSH
• messenger RNA * genetika   metabolismus   MeSH
• posttranskripční úpravy RNA MeSH
• tandemová hmotnostní spektrometrie * metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Hydrogen sulfide (H2S) is an endogenous gasotransmitter with cardioprotective and antiviral effects. In this work, new cysteine-selective nucleoside-H2S-donor hybrid molecules were prepared by conjugating nucleoside biomolecules with a thiol-activatable dithioacetyl group. 5'-Dithioacetate derivatives were synthesized from the canonical nucleosides (uridine, adenosine, cytidine, guanosine and thymidine), and the putative 5'-thio metabolites were also produced from uridine and adenosine. According to our measurements made with an H2S-specific sensor, nucleoside dithioacetates are moderately fast H2S donors, the guanosine derivative showed the fastest kinetics and the adenosine derivative the slowest. The antioxidant activity of 5'-thionucleosides is significantly higher than that of trolox, but lower than that of ascorbic acid, while intact dithioacetates have no remarkable antioxidant effect. In human Calu cells, the guanosine derivative showed a moderate anti-SARS-CoV-2 effect which was also confirmed by virus yield reduction assay. Dithioacetyl-adenosine and its metabolite showed similar acute cardiac effects as adenosine, however, it is noteworthy that both 5'-thio modified adenosines increased left ventricular ejection fraction or stroke volume, which was not observed with native adenosine.

• MeSH
• adenosin analogy a deriváty   MeSH
• antioxidancia * farmakologie   chemie   MeSH
• antivirové látky * farmakologie   chemická syntéza   chemie   MeSH
• buněčné linie MeSH
• farmakoterapie COVID-19 MeSH
• lidé MeSH
• nukleosidy farmakologie   chemie   metabolismus   MeSH
• SARS-CoV-2 účinky léků   metabolismus   MeSH
• sulfan * metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Nonalcoholic fatty liver disease (NAFLD) is characterized by elevated hepatic lipids caused by nonalcoholic factors, where histone lactylation is lately discovered as a modification driving disease progression. This research aimed to explore the role of histone 3 lysine 18 lactylation (H3K18lac) in NAFLD progression using a high-fat diet (HFD)-treated mouse model and free fatty acids (FFA)-treated L-02 cell lines. Lipids accumulation was screened via Oil Red O staining, real-time quantitative polymerase chain reaction (RT-qPCR), western blotting, and commercially available kits. Similarly, molecular mechanism was analyzed using immunoprecipitation (IP), dual-luciferase reporter assay, and RNA decay assay. Results indicated that FFA upregulated lactate dehydrogenase A (LDHA) and H3K18lac levels in L-02 cells. Besides, LDHA-mediated H3K18lac was enriched on the proximal promoter of methyltransferase 3 (METTL3), translating into an increased expression. Moreover, METTL3 or LDHA knockdown relieved lipid accumulation, decreased total cholesterol (TC) and triglyceride (TG) levels, and downregulated lipogenesis-related proteins in FFA-treated L-02 cell lines, in addition to enhancing the m6A and mRNA levels of stearoyl-coenzyme A desaturase 1 (SCD1). The m6A modification of SCD1 was recognized by YTH N6-methyladenosine RNA binding protein F1 (YTHDF1), resulting in enhanced mRNA stability. LDHA was found to be highly expressed in HFD-treated mice, where knocking down LDHA attenuated HFD-induced hepatic steatosis. These findings demonstrated that LDHA-induced H3K18lac promoted NAFLD progression, where LDHA-induced H3K18lac in METTL3 promoter elevated METTL3 expression, thereby promoting m6A methylation and stabilizing SCD1 via a YTHDF1-dependent manner. Keywords: Nonalcoholic fatty liver disease, LDHA, METTL3, YTHDF1, Histone lactylation.

• MeSH
• adenosin * metabolismus   analogy a deriváty   MeSH
• dieta s vysokým obsahem tuků škodlivé účinky   MeSH
• histony * metabolismus   MeSH
• L-laktátdehydrogenasa metabolismus   MeSH
• lidé MeSH
• methyltransferasy * metabolismus   genetika   MeSH
• myši inbrední C57BL * MeSH
• myši MeSH
• nealkoholová steatóza jater * metabolismus   patologie   MeSH
• progrese nemoci * MeSH
• proteiny vázající RNA * metabolismus   genetika   MeSH
• stearyl-CoA-desaturasa * metabolismus   genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

N6-Methyladenosine (m6A) is the predominant internal RNA modification in eukaryotic messenger RNAs (mRNAs) and plays a crucial role in mRNA stability. Here, using human cells, we reveal that m6A sites in the coding sequence (CDS) trigger CDS-m6A decay (CMD), a pathway that is distinct from previously reported m6A-dependent degradation mechanisms. Importantly, CDS m6A sites act considerably faster and more efficiently than those in the 3' untranslated region, which to date have been considered the main effectors. Mechanistically, CMD depends on translation, whereby m6A deposition in the CDS triggers ribosome pausing and transcript destabilization. The subsequent decay involves the translocation of the CMD target transcripts to processing bodies (P-bodies) and recruitment of the m6A reader protein YT521-B homology domain family protein 2 (YTHDF2). Our findings highlight CMD as a previously unknown pathway, which is particularly important for controlling the expression of developmental regulators and retrogenes.

• MeSH
• 3' nepřekládaná oblast MeSH
• adenosin * analogy a deriváty   metabolismus   genetika   MeSH
• HEK293 buňky MeSH
• HeLa buňky MeSH
• lidé MeSH
• messenger RNA * genetika   metabolismus   MeSH
• otevřené čtecí rámce * MeSH
• proteiny vázající RNA * genetika   metabolismus   MeSH
• proteosyntéza * MeSH
• ribozomy metabolismus   genetika   MeSH
• stabilita RNA * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

N6-methyladenosine (m6A) is the most abundant epitranscriptomic mark that regulates the fate of RNA molecules. Recent studies have revealed a bidirectional interaction between m6A modification and the circadian clock. However, the precise temporal dynamics of m6A global enrichment in the central circadian pacemaker have not been fully elucidated. Our study investigates the relationship between FTO demethylase and molecular clocks in primary cells of the suprachiasmatic nucleus (SCN). In addition, we examined the effects of lipopolysaccharide (LPS) on Fto expression and the role of FTO in LPS-induced reactive oxygen species (ROS) production in primary SCN cell culture. We observed circadian rhythmicity in the global m6A levels, which mirrored the rhythmic expression of the Fto demethylase. Silencing FTO using siRNA reduced the mesor of Per2 rhythmicity in SCN primary cells and extended the period of the PER2 rhythm in SCN primary cell cultures from PER2::LUC mice. When examining the immune response, we discovered that exposure to LPS upregulated global m6A levels while downregulating Fto expression in SCN primary cell cultures. Interestingly, we found a loss of circadian rhythmicity in Fto expression following LPS treatment, indicating that the decrease of FTO levels may contribute to m6A upregulation without directly regulating its circadian rhythm. To explore potential protective mechanisms against neurotoxic inflammation, we examined ROS production following LPS treatment in SCN primary cell cultures pretreated with FTO siRNA. We observed a time-dependent pattern of ROS induction, with significant peak at 32 h but not at 20 h after synchronization. Silencing the FTO demethylase abolished ROS induction following LPS exposure, supporting the hypothesis that FTO downregulation serves as a protective mechanism during LPS-induced neuroinflammation in SCN primary cell cultures.

• MeSH
• adenosin * analogy a deriváty   metabolismus   MeSH
• cirkadiánní hodiny * účinky léků   fyziologie   genetika   MeSH
• cirkadiánní proteiny Period metabolismus   genetika   MeSH
• cirkadiánní rytmus účinky léků   fyziologie   MeSH
• gen pro FTO * metabolismus   genetika   MeSH
• kultivované buňky MeSH
• lipopolysacharidy * farmakologie   MeSH
• methylace RNA MeSH
• metylace účinky léků   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• neurozánětlivé nemoci metabolismus   MeSH
• nucleus suprachiasmaticus * metabolismus   účinky léků   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• RNA genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

RNA modifications affect key stages of the RNA life cycle, including splicing, export, decay, and translation. Epitranscriptomic regulations therefore significantly influence cellular physiology and pathophysiology. Here, we selected some of the most abundant modifications and reviewed their roles in the heart and in cardiovascular diseases: N6-methyladenosine (m6A), N6,2'-O-dimethyladenosine (m6Am), N1-methyladenosine (m1A), pseudouridine (?), 5 methylcytidine (m5C), and inosine (I). Dysregulation of epitranscriptomic machinery affecting these modifications vastly changes the cardiac phenotype and is linked with many cardiovascular diseases such as myocardial infarction, cardiomyopathies, or heart failure. Thus, a deeper understanding of these epitranscriptomic changes and their regulatory mechanisms can enhance our knowledge of the molecular underpinnings of prevalent cardiac diseases, potentially paving the way for novel therapeutic strategies. Keywords: Epitranscriptomics, RNA modifications, Epigenetics, m6A, RNA, Heart.

• MeSH
• adenosin analogy a deriváty   metabolismus   MeSH
• epigeneze genetická * MeSH
• lidé MeSH
• myokard metabolismus   MeSH
• posttranskripční úpravy RNA MeSH
• transkriptom MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Specific A3 adenosine receptor (A3AR) agonist, 2-chloro-N6-(3-iodobenzyl)-5'-N-methylcarboxamidoadenosine (2-Cl-IB-MECA), demonstrates anti-proliferative effects on various types of tumor. In the present study, the cytotoxicity of 2-Cl-IB-MECA was analyzed in a panel of tumor and non-tumor cell lines and its anticancer mechanisms in JoPaca-1 pancreatic and Hep-3B hepatocellular carcinoma cell lines were also investigated. Initially, decreased tumor cell proliferation, cell accumulation in the G1 phase and inhibition of DNA and RNA synthesis was found. Furthermore, western blot analysis showed decreased protein expression level of β-catenin, patched1 (Ptch1) and glioma-associated oncogene homolog zinc finger protein 1 (Gli1), which are components of the Wnt/β-catenin and Sonic hedgehog/Ptch/Gli transduction pathways. In concordance with these findings, the protein expression levels of cyclin D1 and c-Myc were reduced. Using a luciferase assay, it was revealed for the first time a decrease in β-catenin transcriptional activity, as an early event following 2-Cl-IB-MECA treatment. In addition, the protein expression levels of multidrug resistance-associated protein 1 and P-glycoprotein (P-gp) were reduced and the P-gp xenobiotic efflux function was also reduced. Next, the enhancing effects of 2-Cl-IB-MECA on the cytotoxicity of conventional chemotherapy was investigated. It was found that 2-Cl-IB-MECA enhanced carboplatin and doxorubicin cytotoxic effects in the JoPaca-1 and Hep-3B cell lines, and a greater synergy was found in the highly tumorigenic JoPaca-1 cell line. This provides a novel in vitro rationale for the utilization of 2-Cl-IB-MECA in combination with chemotherapeutic agents, not only for hepatocellular carcinoma, but also for pancreatic cancer. Other currently used conventional chemotherapeutics, fluorouracil and gemcitabine, showed synergy only when combined with high doses of 2-Cl-IB-MECA. Notably, experiments with A3AR-specific antagonist, N-[9-Chloro-2-(2-furanyl)(1,2,4)-triazolo(1,5-c)quinazolin-5-yl]benzene acetamide, revealed that 2-Cl-IB-MECA had antitumor effects via both A3AR-dependent and -independent pathways. In conclusion, the present study identified novel antitumor mechanisms of 2-Cl-IB-MECA in pancreatic and hepatocellular carcinoma in vitro that further underscores the importance of A3AR agonists in cancer therapy.

• MeSH
• adenosin analogy a deriváty   MeSH
• buněčné linie MeSH
• léková rezistence MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• nádory jater * farmakoterapie   MeSH
• nádory slinivky břišní * genetika   MeSH
• proliferace buněk MeSH
• protein Gli1 genetika   metabolismus   MeSH
• proteiny hedgehog MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

N6-methyladenosine (m6A) and N6,2'-O-dimethyladenosine (m6Am) are two abundant modifications found in mRNAs and ncRNAs that can regulate multiple aspects of RNA biology. They function mainly by regulating interactions with specific RNA-binding proteins. Both modifications are linked to development, disease and stress response. To date, three methyltransferases and two demethylases have been identified that modify adenosines in mammalian mRNAs. Here, we present a comprehensive analysis of the interactomes of these enzymes. PCIF1 protein network comprises mostly factors involved in nascent RNA synthesis by RNA polymerase II, whereas ALKBH5 is closely linked with most aspects of pre-mRNA processing and mRNA export to the cytoplasm. METTL16 resides in subcellular compartments co-inhabited by several other RNA modifiers and processing factors. FTO interactome positions this demethylase at a crossroad between RNA transcription, RNA processing and DNA replication and repair. Altogether, these enzymes share limited spatial interactomes, pointing to specific molecular mechanisms of their regulation.

• MeSH
• adaptorové proteiny signální transdukční genetika   metabolismus   MeSH
• adenosin analogy a deriváty   metabolismus   MeSH
• alfa-ketoglutarát-dependentní dioxygenasa, AlkB homolog 5 genetika   metabolismus   MeSH
• anotace sekvence MeSH
• gen pro FTO genetika   metabolismus   MeSH
• genetická transkripce MeSH
• genová ontologie MeSH
• HEK293 buňky MeSH
• jaderné proteiny genetika   metabolismus   MeSH
• lidé MeSH
• mapování interakce mezi proteiny MeSH
• messenger RNA genetika   metabolismus   MeSH
• methyltransferasy genetika   metabolismus   MeSH
• N-demethylasy genetika   metabolismus   MeSH
• nekódující RNA genetika   metabolismus   MeSH
• oprava DNA MeSH
• protein - isoformy genetika   metabolismus   MeSH
• replikace DNA MeSH
• vazba proteinů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The nucleoside/nucleotide derived antiviral agents have been the most important components of antiviral therapy used in clinics. Recently, the focus of the medicinal chemists within this exciting research field has been affected mainly by the lack of effective therapies for the Hepatitis C virus (HCV) infection and several other "neglected" diseases caused by viruses such as Zika or Dengue. 2'-Methyl modified nucleosides and their monophosphate prodrugs (ProTides) have revolutionized the therapies for HCV in the last few years and, according to the latest research efforts, have also brought a promise for treatment of diseases caused by other members of Flaviviridae family. Here, we report on the design and synthesis of 5'-N and S modified ProTides derived from 2'-methyladenosine. We studied potential applicability of these derivatives as prodrugs of this archetypal antiviral compound.

• MeSH
• adenosin analogy a deriváty   chemie   MeSH
• antivirové látky chemická syntéza   chemie   farmakologie   MeSH
• dusík chemie   MeSH
• Hepacivirus účinky léků   MeSH
• lidé MeSH
• magnetická rezonanční spektroskopie MeSH
• nukleotidy chemie   metabolismus   farmakologie   MeSH
• prekurzory léčiv chemická syntéza   chemie   farmakologie   MeSH
• síra chemie   MeSH
• virus dengue účinky léků   MeSH
• virus zika účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH