Identification and functional analysis of two novel mutations in the CBS gene in Polish patients with homocystinuria

Orendáè, Marek; Pronicka, Ewa; Kubalska, Jolanta; Jánošík, Miroslav; Sokolová, Jitka; Linnebank, Michael; Koch, Hans Georg; Kožich, Viktor

doi:10.1002/humu.9249

Cited by 9 publications

(5 citation statements)

References 11 publications

(15 reference statements)

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“…To get an insight into the possible pathophysiological and therapeutic implications of AdoHcy and AdoMet in CBS deficiency we studied the effect of these two compounds on the activity of mutant proteins in nonparticulate fractions of bacterial extracts. Blood concentration of AdoHcy is increased in patients with CBS deficiency [ Orendac et al, 2004 ] due to its reverse synthesis from homocysteine and adenosine with the help of AdoHcy hydrolase, an enzyme that can be in vitro blocked with different inhibitors. AdoMet is an allosteric activator of CBS that can possibly stimulate the residual activity of mutant proteins and that can be administered as a drug in the form of tosylate.…”

Section: Resultsmentioning

confidence: 99%

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Cystathionine β-synthase mutations: effect of mutation topology on folding and activity

et al. 2010

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Misfolding of mutant enzymes may play an important role in the pathogenesis of cystathionine β-synthase (CBS) deficiency. We examined properties of a series of 27 mutant variants, which together represent 70% of known alleles observed in patients with homocystinuria due to CBS deficiency. The median amount of SDS-soluble mutant CBS polypeptides in the pellet after centrifugation of bacterial extracts was increased by 50% compared to the wild type. Moreover, mutants formed on average only 12% of tetramers and their median activity reached only 3% of the wild-type enzyme. In contrast to the wild-type CBS about half of mutants were not activated by S-adenosylmethionine. Expression at 18°C substantially increased the activity of five mutants in parallel with increasing the amounts of tetramers. We further analyzed the role of solvent accessibility of mutants as a determinant of their folding and activity. Buried mutations formed on average less tetramers and exhibited 23 times lower activity than the solvent exposed mutations. In summary, our results show that topology of mutations predicts in part the behavior of mutant CBS, and that misfolding may be an important and frequent pathogenic mechanism in CBS deficiency. Hum Mutat 31:1–11, 2010. © 2010 Wiley-Liss, Inc.

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Section: Resultsmentioning

confidence: 99%

“…We show that mutations of residues buried in protein globule appear to have more severe effect on folding than those exposed to the solvent. [Katsushima et al, 2006;Orendac et al, 2004;Urreizti et al, 2006] [Hu et al, 1993]; SCE:…”

Section: Introductionmentioning

confidence: 99%

Cystathionine β-synthase mutations: effect of mutation topology on folding and activity

et al. 2010

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“…The study included serum samples from previously described Danish [30] ( n = 4) and Polish [31,32] ( n = 6) CBS-deficient patients (mean age 37.3 ± 7.3 years; five males, five females) and gender- and age-matched healthy unaffected individuals ( n = 14). Two of the Polish CBS-deficient patients had a stroke before diagnosis in childhood at age 3–12.…”

Section: Methodsmentioning

confidence: 99%

Serum Proteome Alterations in Human Cystathionine β-Synthase Deficiency and Ischemic Stroke Subtypes

Sikora

Kupc

et al. 2019

IJMS

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Ischemic stroke induces brain injury via thrombotic or embolic mechanisms involving large or small vessels. Cystathionine β-synthase deficiency (CBS), an inborn error of metabolism, is associated with vascular thromboembolism, the major cause of morbidity and mortality in affected patients. Because thromboembolism involves the brain vasculature in these patients, we hypothesize that CBS deficiency and ischemic stroke have similar molecular phenotypes. We used label-free mass spectrometry for quantification of changes in serum proteomes in CBS-deficient patients (n = 10) and gender/age-matched unaffected controls (n = 14), as well as in patients with cardioembolic (n = 17), large-vessel (n = 26), or lacunar (n = 25) ischemic stroke subtype. In CBS-deficient patients, 40 differentially expressed serum proteins were identified, of which 18 were associated with elevated homocysteine (Hcy) and 22 were Hcy-independent. We also identified Hcy-independent differentially expressed serum proteins in ischemic stroke patients, some of which were unique to a specific subtype: 10 of 32 for cardioembolic vs. large-vessel, six of 33 for cardioembolic vs. lacunar, and six of 23 for large-vessel vs. lacunar. There were significant overlaps between proteins affected by CBS deficiency and ischemic stroke, particularly the cardioembolic subtype, similar to protein overlaps between ischemic stroke subtypes. Top molecular pathways affected by CBS deficiency and ischemic stroke subtypes included acute phase response signaling and coagulation system. Similar molecular networks centering on NFκB were affected by CBS deficiency and stroke subtypes. These findings suggest common mechanisms involved in the pathologies of CBS deficiency and ischemic stroke subtypes.

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“…The study included plasma samples from the Danish 29 (n = 4) and Polish 30,31 non-responsive patients who were treated with betaine. All experimental protocols conformed to the Ethical Guidelines of the World Medical Association Declaration of Helsinki and was approved by the Bioethics Committee of the University of Medical Sciences, Poznań, Poland (decision no.…”

Section: Cbs-deficient Patientsmentioning

confidence: 99%

Cystathionine β-synthase deficiency: different changes in proteomes of thrombosis-resistant Cbs−/− mice and thrombosis-prone CBS−/− humans

Sikora

Marczak

et al. 2020

Sci Rep

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Cystathionine β-synthase (CBS)-deficient patients are prone to vascular thrombosis. In contrast, Cbs −/− mice show no abnormalities in blood coagulation. To identify molecular basis underlying these disparately different thrombotic phenotypes, we analyzed plasma proteomes of Cbs −/− vs. Cbs +/+ mice (8-month-old, 12/group, sex-matched) and CBS −/− vs. CBS +/+ humans (37 ± 7-year-old, 10-14/ group, sex-matched) using label-free mass spectrometry. We identified 117 and 41 differentiating plasma proteins in Cbs −/− mice and CBS −/− humans, respectively. Twenty-one proteins were shared between CBS −/− humans and Cbs −/− mice, with sixteen changed in the opposite direction. Proteins involved in blood coagulation and complement/coagulation cascades represented a greater fraction of the differentiating proteins in CBS −/− patients (51%) than in Cbs −/− mice (21%). Top canonical pathways, identified by Ingenuity Pathways Analysis, such as LXR/RXR, FXR/RXR activation (− log[P-value] = 30-31) and atherosclerosis signaling (− log[P-value] = 10-11) were similarly affected in Cbs −/− mice and CBS −/− humans. The Coagulation System was affected stronger in CBS −/− humans than in Cbs −/− mice (− log[P-value] = 15 vs. 10, respectively) while acute phase response and complement system were affected stronger in Cbs −/− mice (− log[P-value] = 33 and 22, respectively) than in humans (− log[P-value] = 22 and 6, respectively). Other pathways, including IL-7 signaling and B cell development were affected only in Cbs −/− mice. Taken together, our findings suggest that differences in these processes, in particular in the Coagulation System, could account for the thrombotic phenotype in CBS −/− patients and the absence of thrombosis in Cbs −/− mice. Overall, our findings suggest that Cbs −/− mice have a better adaptive response to protect from prothrombotic effects of hyperhomocysteinemia than CBS −/− humans. Patients with cystathionine β-synthase (CBS) deficiency, a rare inborn error of metabolism caused by mutations in the CBS gene, have severely elevated levels of the sulfur-amino acid homocysteine (Hcy) 1 and its metabolites 2. The only known source of Hcy in the human body is the dietary protein methionine, which is converted to Hcy in a sequence of three consecutive reactions with AdoMet and AdoHcy as intermediates. Hcy is further metabolized via three pathways, affording cysteine, methionine, or Hcy-thiolactone 3. The metabolic conversion of Hcy to cysteine is impaired in CBS-deficient patients, causing severe hyperhomocysteinemia (HHcy) 1 and

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Identification and functional analysis of two novel mutations in the CBS gene in Polish patients with homocystinuria

Cited by 9 publications

References 11 publications

Cystathionine β-synthase mutations: effect of mutation topology on folding and activity

Cystathionine β-synthase mutations: effect of mutation topology on folding and activity

Serum Proteome Alterations in Human Cystathionine β-Synthase Deficiency and Ischemic Stroke Subtypes

Cystathionine β-synthase deficiency: different changes in proteomes of thrombosis-resistant Cbs−/− mice and thrombosis-prone CBS−/− humans

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