Adenylosuccinate lyase (ADSL) functions in de novo purine synthesis (DNPS) and the purine nucleotide cycle. ADSL deficiency (ADSLD) causes numerous neurodevelopmental pathologies, including microcephaly and autism spectrum disorder. ADSLD patients have normal serum purine nucleotide levels but exhibit accumulation of dephosphorylated ADSL substrates, S-Ado, and SAICAr, the latter being implicated in neurotoxic effects through unknown mechanisms. We examined the phenotypic effects of ADSL depletion in human cells and their relation to phenotypic outcomes. Using specific interventions to compensate for reduced purine levels or modulate SAICAr accumulation, we found that diminished AMP levels resulted in increased DNA damage signaling and cell cycle delays, while primary ciliogenesis was impaired specifically by loss of ADSL or administration of SAICAr. ADSL-deficient chicken and zebrafish embryos displayed impaired neurogenesis and microcephaly. Neuroprogenitor attrition in zebrafish embryos was rescued by pharmacological inhibition of DNPS, but not increased nucleotide concentration. Zebrafish also displayed phenotypes commonly linked to ciliopathies. Our results suggest that both reduced purine levels and impaired DNPS contribute to neurodevelopmental pathology in ADSLD and that defective ciliogenesis may influence the ADSLD phenotypic spectrum.

• MeSH
• adenylsukcinátlyasa nedostatek   metabolismus   MeSH
• aminoimidazolkarboxamid analogy a deriváty   metabolismus   MeSH
• autistická porucha metabolismus   MeSH
• buněčné linie MeSH
• buněčný cyklus MeSH
• ciliopatie metabolismus   MeSH
• dánio pruhované metabolismus   MeSH
• fenotyp MeSH
• fosfoproteiny metabolismus   MeSH
• kur domácí metabolismus   MeSH
• lidé MeSH
• mikrocefalie metabolismus   MeSH
• neurogeneze * MeSH
• poruchy autistického spektra metabolismus   MeSH
• poruchy metabolismu purinů a pyrimidinů metabolismus   MeSH
• poškození DNA MeSH
• proteiny asociované s mikrotubuly metabolismus   MeSH
• proteiny buněčného cyklu metabolismus   MeSH
• puriny metabolismus   MeSH
• ribonukleotidy metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Intramural MeSH

Purine metabolism plays a ubiquitous role in the physiology of Mycobacterium tuberculosis and other mycobacteria. The purine salvage enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT) is essential for M. tuberculosis growth in vitro; however, its precise role in M. tuberculosis physiology is unclear. Membrane-permeable prodrugs of specifically designed HGPRT inhibitors arrest the growth of M. tuberculosis and represent potential new antituberculosis compounds. Here, we investigated the purine salvage pathway in the model organism Mycobacterium smegmatis Using genomic deletion analysis, we confirmed that HGPRT is the only guanine and hypoxanthine salvage enzyme in M. smegmatis but is not required for in vitro growth of this mycobacterium or survival under long-term stationary-phase conditions. We also found that prodrugs of M. tuberculosis HGPRT inhibitors displayed an unexpected antimicrobial activity against M. smegmatis that is independent of HGPRT. Our data point to a different mode of mechanism of action for these inhibitors than was originally proposed.IMPORTANCE Purine bases, released by the hydrolytic and phosphorolytic degradation of nucleic acids and nucleotides, can be salvaged and recycled. The hypoxanthine-guanine phosphoribosyltransferase (HGPRT), which catalyzes the formation of guanosine-5'-monophosphate from guanine and inosine-5'-monophosphate from hypoxanthine, represents a potential target for specific inhibitor development. Deletion of the HGPRT gene (Δhgprt) in the model organism Mycobacterium smegmatis confirmed that this enzyme is not essential for M. smegmatis growth. Prodrugs of acyclic nucleoside phosphonates (ANPs), originally designed against HGPRT from Mycobacterium tuberculosis, displayed anti-M. smegmatis activities comparable to those obtained for M. tuberculosis but also inhibited the ΔhgprtM. smegmatis strain. These results confirmed that ANPs act in M. smegmatis by a mechanism independent of HGPRT.

• MeSH
• antituberkulotika chemie   farmakologie   MeSH
• hypoxanthinfosforibosyltransferasa antagonisté a inhibitory   chemie   genetika   metabolismus   MeSH
• inhibitory enzymů chemie   farmakologie   MeSH
• katalýza MeSH
• metabolické sítě a dráhy MeSH
• mikrobiální viabilita MeSH
• Mycobacterium smegmatis genetika   růst a vývoj   metabolismus   MeSH
• plazmidy genetika   MeSH
• puriny metabolismus   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

We report for the first time an autosomal recessive inborn error of de novo purine synthesis (DNPS)-PAICS deficiency. We investigated two siblings from the Faroe Islands born with multiple malformations resulting in early neonatal death. Genetic analysis of affected individuals revealed a homozygous missense mutation in PAICS (c.158A>G; p.Lys53Arg) that affects the structure of the catalytic site of the bifunctional enzyme phosphoribosylaminoimidazole carboxylase (AIRC, EC 4.1.1.21)/phosphoribosylaminoimidazole succinocarboxamide synthetase (SAICARS, EC 6.3.2.6) (PAICS). The mutation reduced the catalytic activity of PAICS in heterozygous carrier and patient skin fibroblasts to approximately 50 and 10% of control levels, respectively. The catalytic activity of the corresponding recombinant enzyme protein carrying the mutation p.Lys53Arg expressed and purified from E. coli was reduced to approximately 25% of the wild-type enzyme. Similar to other two known DNPS defects-adenylosuccinate lyase deficiency and AICA-ribosiduria-the PAICS mutation prevented purinosome formation in the patient's skin fibroblasts, and this phenotype was corrected by transfection with the wild-type but not the mutated PAICS. Although aminoimidazole ribotide (AIR) and aminoimidazole riboside (AIr), the enzyme substrates that are predicted to accumulate in PAICS deficiency, were not detected in patient's fibroblasts, the cytotoxic effect of AIr on various cell lines was demonstrated. PAICS deficiency is a newly described disease that enhances our understanding of the DNPS pathway and should be considered in the diagnosis of families with recurrent spontaneous abortion or early neonatal death.

• MeSH
• adenylsukcinátlyasa nedostatek   MeSH
• autistická porucha MeSH
• fatální výsledek MeSH
• fenotyp MeSH
• karboxylyasy genetika   metabolismus   MeSH
• lidé MeSH
• mnohočetné abnormality genetika   MeSH
• mutace MeSH
• novorozenec MeSH
• peptidsynthasy genetika   metabolismus   MeSH
• perinatální smrt MeSH
• poruchy metabolismu purinů a pyrimidinů MeSH
• puriny biosyntéza   metabolismus   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• novorozenec MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Dánsko MeSH

Metabolism of purine bases remains poorly understood in the pathogenic bacterium Mycobacterium tuberculosis and closely related, nonpathogenic Mycobacterium smegmatis (Msm). To gain insight into the purine metabolism in mycobacteria, we tested uptake of purine bases with a ΔpurF Msm mutant with an inactive purine de novo biosynthesis pathway and confirmed that hypoxanthine and guanine, but not xanthine, can serve as nucleotide precursors for recycling in the salvage pathway. Further, we focused on purine catabolism in wild-type (wt) Msm. We found that only xanthine and guanine could serve as a sole nitrogen source for wt Msm. These data confirm that Msm catabolism of purines is directed mainly via oxidative guanine to xanthine interconversion and not through metabolic conversion of hypoxanthine to xanthine. Our data represent the first experimental evidence confirming the use of 8-oxo-purines as a nitrogen source by Msm.

• MeSH
• atypické mykobakteriální infekce metabolismus   mikrobiologie   MeSH
• guanin metabolismus   MeSH
• lidé MeSH
• Mycobacterium smegmatis izolace a purifikace   metabolismus   MeSH
• puriny metabolismus   MeSH
• xanthin metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Hereditary xanthinuria (type I) is caused by an inherited deficiency of the xanthine oxidorectase (XDH/XO), and is characterized by very low concentration of uric acid in blood and urine and high concentration of urinary xanthine, leading to urolithiasis. Type II results from a combined deficiency of XDH/XO and aldehyde oxidase. Patients present with hematuria, renal colic, urolithiasis or even acute renal failure. Clinical symptoms are the same for both types. In a third type, clinically distinct, sulfite oxidase activity is missing as well as XDH/XO and aldehyde oxidase. The prevalence is not known, but about 150 cases have been described so far. Hypouricemia is sometimes overlooked, that´s why we have set up the diagnostic flowchart. This consists of a) evaluation of uric acid concentrations in serum and urine with exclusion of primary renal hypouricemia, b) estimation of urinary xanthine, c) allopurinol loading test, which enables to distinguish type I and II; and finally assay of xanthine oxidoreductase activity in plasma with molecular genetic analysis. Following this diagnostic procedure we were able to find first patients with hereditary xanthinuria in our Czech population. We have detected nine cases, which is one of the largest group worldwide. Four patients were asymptomatic. All had profound hypouricemia, which was the first sign and led to referral to our department. Urinary concentrations of xanthine were in the range of 170-598 mmol/mol creatinine (normal < 30 mmol/mol creatinine). Hereditary xanthinuria is still unrecognized disorder and subjects with unexplained hypouricemia need detailed purine metabolic investigation.

• MeSH
• aldehydoxidasa krev   nedostatek   moč   MeSH
• alopurinol metabolismus   MeSH
• diferenciální diagnóza MeSH
• dítě MeSH
• dospělí MeSH
• kyselina močová krev   moč   MeSH
• lidé MeSH
• močové kameny krev   epidemiologie   moč   MeSH
• poruchy metabolismu purinů a pyrimidinů krev   diagnóza   epidemiologie   moč   MeSH
• předškolní dítě MeSH
• puriny metabolismus   MeSH
• vrozené poruchy metabolismu krev   diagnóza   epidemiologie   moč   MeSH
• vrozené poruchy tubulárního transportu krev   epidemiologie   moč   MeSH
• xanthin krev   moč   MeSH
• xanthindehydrogenasa krev   nedostatek   metabolismus   moč   MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé MeSH
• předškolní dítě MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika MeSH

We synthesized a small library of eighteen 5-substituted pyrimidine or 7-substituted 7-deazapurine nucleoside triphosphates bearing methyl, ethynyl, phenyl, benzofuryl or dibenzofuryl groups through cross-coupling reactions of nucleosides followed by triphosphorylation or through direct cross-coupling reactions of halogenated nucleoside triphosphates. We systematically studied the influence of the modification on the efficiency of T7 RNA polymerase catalyzed synthesis of modified RNA and found that modified ATP, UTP and CTP analogues bearing smaller modifications were good substrates and building blocks for the RNA synthesis even in difficult sequences incorporating multiple modified nucleotides. Bulky dibenzofuryl derivatives of ATP and GTP were not substrates for the RNA polymerase. In the case of modified GTP analogues, a modified procedure using a special promoter and GMP as initiator needed to be used to obtain efficient RNA synthesis. The T7 RNA polymerase synthesis of modified RNA can be very efficiently used for synthesis of modified RNA but the method has constraints in the sequence of the first three nucleotides of the transcript, which must contain a non-modified G in the +1 position.

• MeSH
• adenosintrifosfát analogy a deriváty   metabolismus   MeSH
• bakteriofág T7 enzymologie   MeSH
• cytidintrifosfát analogy a deriváty   metabolismus   MeSH
• DNA řízené RNA-polymerasy metabolismus   MeSH
• purinové nukleosidy chemie   metabolismus   MeSH
• puriny chemie   metabolismus   MeSH
• pyrimidinové nukleosidy chemie   metabolismus   MeSH
• RNA chemie   metabolismus   MeSH
• substrátová specifita MeSH
• uridintrifosfát analogy a deriváty   metabolismus   MeSH
• virové proteiny metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH

Dna, arthritis urica, je metabolické onemocnění způsobené zánětlivou reakcí na ukládání urátových krystalů do kloubů a měkkých tkání. Chronická hyperurikémie, kauzální příčina dny, vzniká nerovnováhou mezi endogenní produkcí a exkrecí kyseliny močové. Nejčastějším mechanismem vedoucím ke vzniku hyperurikémie je snížená exkrece kyseliny močové. Transport urátu je komplexní proces zahrnující řadu transmembránových proteinů zajišťujících reabsorpci (majoritně URAT1, GLUT9) a sekreci (ABCG2) na apikální i bazolaterální straně proximálních tubulů a v případě ABCG2 i s významným podílem transportu v gastrointestinálním traktu. Nové znalosti o exkreci kyseliny močové umožnily vývoj nové strategie v léčbě hyperurikémie mechanismem blokace urátových transportérů. Znalosti genetického pozadí urikémie jsou podstatné pro včasné rozpoznání etiologie onemocnění, volbě vhodné léčby a také k monitorování compliance ze strany pacienta. Detailní vyšetření purinového metabolismu a exkrece kyseliny močové ve specializovaných laboratořích je vhodné zejména u pacientů s časným nástupem a/nebo familiárním výskytem onemocnění.

Gout, arthritis urica, is a metabolic disorder caused by an inflammatory reaction to the deposition of urate crystals into joints and soft tissues. Chronic hyperuricaemia, the cause of the gout, results in an imbalance between endogenous production and excretion of uric acid. The most common mechanism leading to hyperuricaemia is decreased excretion of uric acid. Urate transport is a complex process involving a number of transmembrane proteins that provide reabsorption (mostly URAT1, GLUT9) and secretion (ABCG2) on the apical and basolateral side of the proximal tubules. ABCG2, with a significant proportion, provides transport in the gastrointestinal tract. New knowledge on uric acid excretion has allowed the development of a new strategy in the treatment of hyperuricaemia by blocking urate transporters. Knowledge of the genetic background of uricemia is essential for early identification of the aetiology of the disease, the choice of appropriate treatment, and also the monitoring of compliance by the patient. Detailed examination of purine metabolism and uric acid excretion in specialized laboratories is particularly useful for patients with early onset and / or familial outbreaks of the disease.

• Klíčová slova
• urátové transportéry,
• MeSH
• ABC transportér z rodiny G, člen 2 fyziologie   genetika   MeSH
• dna (nemoc) * diagnóza   epidemiologie   etiologie   MeSH
• hyperurikemie * diagnóza   etiologie   genetika   MeSH
• intersticiální nefritida diagnóza   genetika   MeSH
• kyselina močová chemie   MeSH
• Leschův-Nyhanův syndrom diagnóza   genetika   MeSH
• lidé MeSH
• proteiny usnadňující transport glukosy fyziologie   genetika   MeSH
• puriny metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• přehledy MeSH

BACKGROUND: Uric acid is the metabolic end product of purine metabolism in humans. Altered serum and urine uric acid level (both above and below the reference ranges) is an indispensable marker in detecting rare inborn errors of metabolism. We describe different case scenarios of 4 Sri Lankan patients related to abnormal uric acid levels in blood and urine. CASE 1: A one-and-half-year-old boy was investigated for haematuria and a calculus in the bladder. Xanthine crystals were seen in microscopic examination of urine sediment. Low uric acid concentrations in serum and low urinary fractional excretion of uric acid associated with high urinary excretion of xanthine and hypoxanthine were compatible with xanthine oxidase deficiency. CASE 2: An 8-month-old boy presented with intractable seizures, feeding difficulties, screaming episodes, microcephaly, facial dysmorphism and severe neuro developmental delay. Low uric acid level in serum, low fractional excretion of uric acid and radiological findings were consistent with possible molybdenum cofactor deficiency. Diagnosis was confirmed by elevated levels of xanthine, hypoxanthine and sulfocysteine levels in urine. CASE 3: A 3-year-10-month-old boy presented with global developmental delay, failure to thrive, dystonia and self-destructive behaviour. High uric acid levels in serum, increased fractional excretion of uric acid and absent hypoxanthine-guanine phosphoribosyltransferase enzyme level confirmed the diagnosis of Lesch-Nyhan syndrome. CASE 4: A 9-year-old boy was investigated for lower abdominal pain, gross haematuria and right renal calculus. Low uric acid level in serum and increased fractional excretion of uric acid pointed towards hereditary renal hypouricaemia which was confirmed by genetic studies. CONCLUSION: Abnormal uric acid level in blood and urine is a valuable tool in screening for clinical conditions related to derangement of the nucleic acid metabolic pathway.

• MeSH
• dítě MeSH
• kojenec MeSH
• kyselina močová krev   MeSH
• lidé MeSH
• metabolické sítě a dráhy MeSH
• plošný screening * MeSH
• předškolní dítě MeSH
• puriny metabolismus   MeSH
• vrozené poruchy metabolismu krev   diagnóza   MeSH
• Check Tag
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH

KEY MESSAGE: An affinity-based chemical proteomic technique enabled direct identification of BAP-interacting proteins in wheat, including the well-known cytokinin-binder, cytokinin-binding protein 1. In this work, we show the development of a chemical proteomic technique for the identification of proteins binding to natural aromatic cytokinins (CKs). 6-benzylaminopurine (BAP) and documented CK-binder, wheat germ-allocated cytokinin-binding protein 1 (CBP-1), were suggested as an ideal proof-of concept affinity pair. Therefore, wheat grains were chosen as a model plant material. The BAP affinity beads were prepared by the immobilization of synthesized BAP-derived ligand to a commercial, pre-activated resin and used to isolate target proteins. The proteomic analysis of complex plant extracts is often complicated by the presence of highly abundant background proteins; in this case, the omnipresent alpha-amylase inhibitors (AAIs). To cope with this problem, we included SDS-PAGE, in-gel trypsin digestion and fraction pooling prior to shotgun analysis, which brought about an obvious drop in the signals belonging to the obstructing proteins. This was accompanied by a sharp increase in the number of identified BAP targets in comparison to a conventional in-solution digestion approach. To distinguish specific CK-binding proteins from those having a general affinity for nucleotide-like compounds, competitive pull-downs with natural nucleotides and free BAP were included in every affinity experiment. By this approach, we were able to identify a group of BAP-interacting proteins, which were subsequently found to be related to biological processes affected by CKs. Moreover, the selected affinity enrichment strategy was verified by the detection of the aforementioned CK-interacting protein, CBP-1. We propose that the developed method represents a promising tool for appealing research of as yet unknown CK molecular partners in plants.

• MeSH
• benzylové sloučeniny metabolismus   MeSH
• chromatografie kapalinová MeSH
• cytokininy metabolismus   MeSH
• elektroforéza v polyakrylamidovém gelu MeSH
• jedlá semena metabolismus   MeSH
• proteom metabolismus   MeSH
• proteomika metody   MeSH
• pšenice metabolismus   MeSH
• puriny metabolismus   MeSH
• rostlinné proteiny metabolismus   MeSH
• tandemová hmotnostní spektrometrie MeSH
• vazba proteinů MeSH
• Publikační typ
• časopisecké články MeSH

Purines are essential molecules for nucleic acid synthesis and are the most common carriers of chemical energy in all living organisms. The cellular pool of purines is maintained by the balance between their de novo synthesis (DNPS), recycling and degradation. DNPS includes ten reactions catalysed by six enzymes. To date, two genetically determined disorders of DNPS enzymes have been described, and the existence of other defects manifested by neurological symptoms and the accumulation of DNPS intermediates in bodily fluids is highly presumable. In the current study, we prepared specific recombinant DNPS enzymes and used them for the biochemical preparation of their commercially unavailable substrates. These compounds were used as standards for the development and validation of quantitative liquid chromatography-tandem mass spectrometry (LC-MS/MS). To simulate manifestations of known and putative defects of DNPS we prepared CRISPR-Cas9 genome-edited HeLa cells deficient for the individual steps of DNPS (CR-cells), assessed the substrates accumulation in cell lysates and growth media and tested how the mutations affect assembly of the purinosome, the multi-enzyme complex of DNPS enzymes. In all model cell lines with the exception of one, an accumulation of the substrate(s) for the knocked out enzyme was identified. The ability to form the purinosome was reduced. We conclude that LC-MS/MS analysis of the dephosphorylated substrates of DNPS enzymes in bodily fluids is applicable in the selective screening of the known and putative DNPS disorders. This approach should be considered in affected individuals with neurological and neuromuscular manifestations of unknown aetiology. Prepared in vitro human model systems can serve in various studies that aim to provide a better characterization and understanding of physiology and pathology of DNPS, to study the role of each DNPS protein in the purinosome formation and represent an interesting way for the screening of potential therapeutic agents.

• MeSH
• chromatografie kapalinová MeSH
• CRISPR-Cas systémy * MeSH
• HeLa buňky MeSH
• lidé MeSH
• multienzymové komplexy chemie   genetika   metabolismus   MeSH
• mutace MeSH
• puriny biosyntéza   metabolismus   MeSH
• substrátová specifita MeSH
• tandemová hmotnostní spektrometrie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH