Niemann-Pick disease type C1 (NPC1) is a severe neurovisceral lysosomal storage disorder with significant psychosocial impacts for affected families and, due to financial costs, also for the healthcare systems. Accurate NPC1 diagnostics are fundamental prerequisites for any therapy. Moreover, drugs currently used for clinical treatment of NPC, even though not targeting the primary cause, are expensive and their application must be rationalized. The aim of the project is to characterize molecular consequences of NPC1 mutations on mRNA and protein levels and to test selected mutants for their responsiveness to chaperone treatment. NPC1 promoter will be studied to show if its polymorphisms or other sequence variants influence transcription levels and thus contribute to NPC1 pathogenesis. The results of the laboratory analyses correlated to clinical severity and quality-of-life data will enable a critical selection of standards to be embedded into newly introduced diagnostic algorithm of NPC1 disease.

Niemann-Pickova choroba typ C1 (NPC1) je závažné neuroviscerální lysosomální střádací onemocnění s významnými psychosociálními dopady pro postižené rodiny a z hlediska finančního i pro zdravotní systém jako celek. Kauzální terapie NPC1 není v tuto chvíli dostupná. Aplikace přípravků zaváděných do klinické praxe je nákladná a proto je rychlá a efektivní diagnostika NPC1 nutným předpokladem úspěchu terapeutického zásahu, stejně jako racionalizace jejich podání. V projektu navrhovaná specifikace molekulárně patofysiologických důsledků mutací genu NPC1 na úrovni mRNA a proteinu pomůže určit efekt nových způsobů léčby. Funkční studie promotorové oblasti genu NPC1 ukáže, zda polymorfismy nebo další nalezené genetické změny ovlivňují úroveň transkripce a tím se podílejí na molekulární patogenezi NPC1. Navrhovaná laboratorní vyšetření v korelaci s klinickými údaji umožní určit nejen postupy vhodné k zařazení mezi diagnostické standardy ale i jejich využitelnost v nově vytvářeném diagnostickém algoritmu NPC1.

• MeSH
• algoritmy MeSH
• diagnostické techniky molekulární metody   normy   MeSH
• diferenciální diagnóza MeSH
• dospělí MeSH
• genetická transkripce MeSH
• imunohistochemie MeSH
• kvalita života MeSH
• messenger RNA analýza   MeSH
• mladiství MeSH
• mutace MeSH
• Niemannova-Pickova nemoc typu C diagnóza   MeSH
• polymorfismus genetický MeSH
• psychosociální deprivace MeSH
• socioekonomické faktory MeSH
• Check Tag
• dospělí MeSH
• mladiství MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• neurologie
• genetika, lékařská genetika
• biologie
• NLK Publikační typ
• závěrečné zprávy o řešení grantu IGA MZ ČR

Autosomal-dominant tubulo-interstitial kidney disease (ADTKD) encompasses a group of disorders characterized by renal tubular and interstitial abnormalities, leading to slow progressive loss of kidney function requiring dialysis and kidney transplantation. Mutations in UMOD, MUC1, and REN are responsible for many, but not all, cases of ADTKD. We report on two families with ADTKD and congenital anemia accompanied by either intrauterine growth retardation or neutropenia. Ultrasound and kidney biopsy revealed small dysplastic kidneys with cysts and tubular atrophy with secondary glomerular sclerosis, respectively. Exclusion of known ADTKD genes coupled with linkage analysis, whole-exome sequencing, and targeted re-sequencing identified heterozygous missense variants in SEC61A1-c.553A>G (p.Thr185Ala) and c.200T>G (p.Val67Gly)-both affecting functionally important and conserved residues in SEC61. Both transiently expressed SEC6A1A variants are delocalized to the Golgi, a finding confirmed in a renal biopsy from an affected individual. Suppression or CRISPR-mediated deletions of sec61al2 in zebrafish embryos induced convolution defects of the pronephric tubules but not the pronephric ducts, consistent with the tubular atrophy observed in the affected individuals. Human mRNA encoding either of the two pathogenic alleles failed to rescue this phenotype as opposed to a complete rescue by human wild-type mRNA. Taken together, these findings provide a mechanism by which mutations in SEC61A1 lead to an autosomal-dominant syndromic form of progressive chronic kidney disease. We highlight protein translocation defects across the endoplasmic reticulum membrane, the principal role of the SEC61 complex, as a contributory pathogenic mechanism for ADTKD.

• MeSH
• alely MeSH
• anemie genetika   MeSH
• biopsie MeSH
• chronická nemoc MeSH
• dánio pruhované embryologie   genetika   MeSH
• dítě MeSH
• dominantní geny MeSH
• dospělí MeSH
• endoplazmatické retikulum metabolismus   MeSH
• exom genetika   MeSH
• fenotyp MeSH
• Golgiho aparát metabolismus   MeSH
• heterozygot * MeSH
• lidé středního věku MeSH
• lidé MeSH
• messenger RNA analýza   genetika   MeSH
• missense mutace genetika   MeSH
• mladý dospělý MeSH
• molekulární modely MeSH
• mutace * MeSH
• nemoci ledvin genetika   patologie   MeSH
• neutropenie genetika   MeSH
• novorozenec MeSH
• progrese nemoci MeSH
• rodokmen MeSH
• růstová retardace plodu genetika   MeSH
• sekvence aminokyselin MeSH
• senioři MeSH
• syndrom MeSH
• translokační kanály SEC chemie   genetika   MeSH
• zvířata MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• novorozenec MeSH
• senioři MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH

Classical homocystinuria is caused by mutations in the cystathionine β-synthase (CBS) gene. Previous experiments in bacterial and yeast cells showed that many mutant CBS enzymes misfold and that chemical chaperones enable proper folding of a number of mutations. In the present study, we tested the extent of misfolding of 27 CBS mutations previously tested in E. coli under the more folding-permissive conditions of mammalian CHO-K1 cells and the ability of chaperones to rescue the conformation of these mutations. Expression of mutations in mammalian cells increased the median activity 16-fold and the amount of tetramers 3.2-fold compared with expression in bacteria. Subsequently, we tested the responses of seven selected mutations to three compounds with chaperone-like activity. Aminooxyacetic acid and 4-phenylbutyric acid exhibited only a weak effect. In contrast, heme arginate substantially increased the formation of mutant CBS protein tetramers (up to sixfold) and rescued catalytic activity (up to ninefold) of five out of seven mutations (p.A114V, p.K102N, p.R125Q, p.R266K, and p.R369C). The greatest effect of heme arginate was observed for the mutation p.R125Q, which is non-responsive to in vivo treatment with vitamin B(6). Moreover, the heme responsiveness of the p.R125Q mutation was confirmed in fibroblasts derived from a patient homozygous for this genetic variant. Based on these data, we propose that a distinct group of heme-responsive CBS mutations may exist and that the heme pocket of CBS may become an important target for designing novel therapies for homocystinuria.

• MeSH
• arginin farmakologie   MeSH
• CHO buňky MeSH
• Cricetulus MeSH
• cystathionin-beta-synthasa genetika   metabolismus   MeSH
• fenotyp MeSH
• fibroblasty účinky léků   enzymologie   MeSH
• genetická predispozice k nemoci MeSH
• hem farmakologie   MeSH
• homocystinurie diagnóza   farmakoterapie   enzymologie   genetika   MeSH
• homozygot MeSH
• katalytická doména MeSH
• konformace proteinů MeSH
• lidé MeSH
• molekulární chaperony farmakologie   MeSH
• molekulární modely MeSH
• mutace * MeSH
• poruchy proteostázy diagnóza   farmakoterapie   enzymologie   genetika   MeSH
• sbalování proteinů MeSH
• substrátová specifita MeSH
• transfekce MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• práce podpořená grantem MeSH

Adenosine kinase (ADK) from Mycobacterium tuberculosis (Mtb) was selected as a target for design of antimycobacterial nucleosides. Screening of 7-(het)aryl-7-deazaadenine ribonucleosides with Mtb and human (h) ADKs and testing with wild-type and drug-resistant Mtb strains identified specific inhibitors of Mtb ADK with micromolar antimycobacterial activity and low cytotoxicity. X-ray structures of complexes of Mtb and hADKs with 7-ethynyl-7-deazaadenosine showed differences in inhibitor interactions in the adenosine binding sites. 1D (1)H STD NMR experiments revealed that these inhibitors are readily accommodated into the ATP and adenosine binding sites of Mtb ADK, whereas they bind preferentially into the adenosine site of hADK. Occupation of the Mtb ADK ATP site with inhibitors and formation of catalytically less competent semiopen conformation of MtbADK after inhibitor binding in the adenosine site explain the lack of phosphorylation of 7-substituted-7-deazaadenosines. Semiempirical quantum mechanical analysis confirmed different affinity of nucleosides for the Mtb ADK adenosine and ATP sites.

• MeSH
• adenin analogy a deriváty   chemie   MeSH
• adenosinkinasa antagonisté a inhibitory   chemie   metabolismus   MeSH
• adenosintrifosfát metabolismus   MeSH
• antituberkulotika chemie   farmakologie   MeSH
• konformace proteinů MeSH
• krystalografie rentgenová MeSH
• lidé MeSH
• mikrobiální testy citlivosti MeSH
• Mycobacterium tuberculosis účinky léků   enzymologie   MeSH
• nukleární magnetická rezonance biomolekulární MeSH
• preklinické hodnocení léčiv MeSH
• ribonukleosidy chemie   farmakologie   MeSH
• vazebná místa MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

This work describes novel in vitro inhibitors of human mitochondrial (mdN) and cytosolic (cdN) 5'(3')-deoxynucleotidases. We designed a series of derivatives of the lead compound (S)-1-[2-deoxy-3,5-O-(phosphonobenzylidene)-β-d-threo-pentofuranosyl]thymine bearing various substituents in the para position of the benzylidene moiety. Detailed kinetic study revealed that certain para substituents increase the inhibitory potency (iodo derivative; K = 2.71 μM) and some induce a shift in selectivity toward cdN (carboxy derivative, K = 11.60 μM; iodoxy derivative, K = 6.60 μM). Crystal structures of mdN in complex with three of these compounds revealed that various para substituents lead to two alternative inhibitor binding modes within the enzyme active site. Two binding modes were also identified for cdN complexes by heteronuclear NMR spectroscopy.

• MeSH
• 5'-nukleotidasa antagonisté a inhibitory   metabolismus   MeSH
• cytosol enzymologie   MeSH
• inhibitory enzymů chemická syntéza   chemie   farmakologie   MeSH
• lidé MeSH
• mitochondrie enzymologie   MeSH
• molekulární konformace MeSH
• organofosfonáty chemická syntéza   chemie   farmakologie   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

O-Acetylserine(thiol)lyases (OAS-TLs) play a pivotal role in a sulfur assimilation pathway incorporating sulfide into amino acids in microorganisms and plants, however, these enzymes have not been found in the animal kingdom. Interestingly, the genome of the roundworm Caenorhabditis elegans contains three expressed genes predicted to encode OAS-TL orthologs (cysl-1-cysl-3), and a related pseudogene (cysl-4); these genes play different roles in resistance to hypoxia, hydrogen sulfide and cyanide. To get an insight into the underlying molecular mechanisms we purified the three recombinant worm OAS-TL proteins, and we determined their enzymatic activities, substrate binding affinities, quaternary structures and the conformations of their active site shapes. We show that the nematode OAS-TL orthologs can bind O-acetylserine and catalyze the canonical reaction although this ligand may more likely serve as a competitive inhibitor to natural substrates instead of being a substrate for sulfur assimilation. In addition, we propose that S-sulfocysteine may be a novel endogenous substrate for these proteins. However, we observed that the three OAS-TL proteins are conformationally different and exhibit distinct substrate specificity. Based on the available evidences we propose the following model: CYSL-1 interacts with EGL-9 and activates HIF-1 that upregulates expression of genes detoxifying sulfide and cyanide, the CYSL-2 acts as a cyanoalanine synthase in the cyanide detoxification pathway and simultaneously produces hydrogen sulfide, while the role of CYSL-3 remains unclear although it exhibits sulfhydrylase activity in vitro. All these data indicate that C. elegans OAS-TL paralogs have distinct cellular functions and may play different roles in maintaining hydrogen sulfide homeostasis.

• MeSH
• buněčné jádro chemie   enzymologie   genetika   MeSH
• Caenorhabditis elegans enzymologie   genetika   MeSH
• cysteinsynthasa chemie   genetika   metabolismus   MeSH
• homeostáza fyziologie   MeSH
• katalytická doména MeSH
• kyanidy metabolismus   MeSH
• proteiny Caenorhabditis elegans chemie   genetika   metabolismus   MeSH
• serin analogy a deriváty   chemie   genetika   metabolismus   MeSH
• substrátová specifita MeSH
• sulfan chemie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Protein misfolding due to missense mutations is a common pathogenic mechanism in cystathionine β-synthase (CBS) deficiency. In our previous studies, we successfully expressed, purified, and characterized nine CBS mutant enzymes containing the following patient mutations: P49L, P78R, A114V, R125Q, E176K, R266K, P422L, I435T, and S466L. These purified mutants exhibited full heme saturation, normal tetrameric assembly, and high catalytic activity. In this work, we used several spectroscopic and proteolytic techniques to provide a more thorough insight into the conformation of these mutant enzymes. Far-UV circular dichroism, fluorescence, and second-derivative UV spectroscopy revealed that the spatial arrangement of these CBS mutants is similar to that of the wild type, although the microenvironment of the chromophores may be slightly altered. Using proteolysis with thermolysin under native conditions, we found that the majority of the studied mutants is more susceptible to cleavage, suggesting their increased local flexibility or propensity for local unfolding. Interestingly, the presence of the CBS allosteric activator, S-adenosylmethionine (AdoMet), increased the rate of cleavage of the wild type and the AdoMet-responsive mutants, while the proteolytic rate of the AdoMet-unresponsive mutants was not significantly changed. Pulse proteolysis analysis suggested that the protein structure of the R125Q and E176K mutants is significantly less stable than that of the wild type and the other mutants. Taken together, the proteolytic data shows that the conformation of the pathogenic mutants is altered despite retained catalytic activity and normal tetrameric assembly. This study demonstrates that the proteolytic techniques are useful tools for the assessment of the biochemical penalty of missense mutations in CBS.

• MeSH
• cirkulární dichroismus MeSH
• cystathionin-beta-synthasa nedostatek   genetika   metabolismus   MeSH
• Escherichia coli metabolismus   MeSH
• konformace proteinů MeSH
• lidé MeSH
• missense mutace MeSH
• molekulární modely MeSH
• proteolýza MeSH
• S-adenosylmethionin MeSH
• sbalování proteinů MeSH
• spektrofotometrie ultrafialová MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Protein misfolding has been proposed to be a common pathogenic mechanism in many inborn errors of metabolism including cystathionine β-synthase (CBS) deficiency. In this work, we describe the structural properties of nine CBS mutants that represent a common molecular pathology in the CBS gene. Using thermolysin in two proteolytic techniques, we examined conformation of these mutants directly in crude cell extracts after expression in E. coli. Proteolysis with thermolysin under native conditions appeared to be a useful technique even for very unstable mutant proteins, whereas pulse proteolysis in a urea gradient had limited values for the study of the majority of CBS mutants due to their instability. Mutants in the active core had either slightly increased unfolding (p.A114V, p.E302K and p.G307S) or extensive unfolding with decreased stability (p.H65R, p.T191M, p.I278T and p.R369C). The extent of the unfolding inversely correlated with the previously determined degree of tetrameric assembly and with the catalytic activity. In contrast, mutants bearing aminoacid substitutions in the C-terminal regulatory domain (p.R439Q and p.D444N) had increased global stability with decreased flexibility. This study shows that proteolytic techniques can reveal conformational abnormalities even for CBS mutants that have activity and/or a degree of assembly similar to the wild-type enzyme. We present here a methodological strategy that may be used in cell lysates to evaluate properties of proteins that tend to misfold and aggregate and that may be important for conformational studies of disease-causing mutations in the field of inborn errors of metabolism.

• MeSH
• časové faktory MeSH
• cystathionin-beta-synthasa genetika   MeSH
• denaturace proteinů MeSH
• dimerizace MeSH
• Escherichia coli metabolismus   MeSH
• kinetika MeSH
• konformace proteinů MeSH
• lidé MeSH
• močovina chemie   MeSH
• mutace MeSH
• rozpouštědla MeSH
• sbalování proteinů MeSH
• terciární struktura proteinů MeSH
• thermolysin chemie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

CBSs (cystathionine β-synthases) are eukaryotic PLP (pyridoxal 5 *-phosphate)-dependent proteins that maintain cellular homocysteine homoeostasis and produce cystathionine and hydrogen sulfide. In the present study, we describe a novel structural arrangement of the CBS enzyme encoded by the cbs-1 gene of the nematode Caenorhabditis elegans. The CBS-1 protein contains a unique tandem repeat of two evolutionarily conserved catalytic regions in a single polypeptide chain. These repeats include a catalytically active C-terminal module containing a PLP-binding site and a less conserved N-terminal module that is unable to bind the PLP cofactor and cannot catalyse CBS reactions, as demonstrated by analysis of truncated variants and active-site mutant proteins. In contrast with other metazoan enzymes, CBS-1 lacks the haem and regulatory Bateman domain essential for activation by AdoMet (S-adenosylmethionine) and only forms monomers. We determined the tissue and subcellular distribution of CBS-1 and showed that cbs-1 knockdown by RNA interference leads to delayed development and to an approximately 10-fold elevation of homocysteine concentrations in nematode extracts. The present study provides the first insight into the metabolism of sulfur amino acids and hydrogen sulfide in C. elegans and shows that nematode CBSs possess a structural feature that is unique among CBS proteins.

• MeSH
• biokatalýza MeSH
• Caenorhabditis elegans enzymologie   MeSH
• cystathionin-beta-synthasa chemie   genetika   metabolismus   MeSH
• cytoplazma enzymologie   MeSH
• homeostáza MeSH
• homocystein metabolismus   MeSH
• konzervovaná sekvence MeSH
• kvarterní struktura proteinů MeSH
• lidé MeSH
• molekulární modely MeSH
• molekulární sekvence - údaje MeSH
• orgánová specificita MeSH
• sekvence aminokyselin MeSH
• sekvenční seřazení MeSH
• terciární struktura proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• Caenorhabditis elegans * MeSH
• cystathionin-beta-synthasa * MeSH
• cysteinsynthasa * MeSH
• homocystein MeSH
• lidé MeSH
• proteiny Caenorhabditis elegans MeSH
• regulace genové exprese enzymů MeSH
• sulfan * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH