Ribozomy jsou buněčné struktury zodpovědné za syntézu proteinů. Utvářejí se během složitého procesu, který se nazývá biogeneze ribozomů. Vrozené ribozomopatie jsou heterogenní skupinou onemocnění, jejichž příčinou jsou genetické abnormality způsobující narušení biogeneze a funkce ribozomů. Mutovány mohou být geny ribozomálních proteinů i dalších faktorů podílejících se na ribozomální biogenezi. Charakteristickým znakem vrozených ribozomopatií jsou tkáňově specifická poškození a zvýšené riziko rozvoje nádorových onemocnění. Nedávný výzkum navíc odhalil, že klinicky významné jsou i somatické mutace v genech pro ribozomální proteiny, jelikož se podílejí na procesu nádorové transformace. V tomto souhrnném článku je popsáno patofyziologické působení ribozomálních defektů na buněčné a molekulární úrovni i možné mechanizmy podporující onkogenezi. Článek dále pojednává o léčbě ribozomopatií a představuje nové terapeutické možnosti.
Ribosomes are cellular structures responsible for protein synthesis. They are formed during a complex process called ribosome biogenesis. Congenital ribosomopathies are a heterogeneous group of diseases caused by genetic abnormalities that disrupt ribosome biogenesis and function with causative mutations affecting genes encoding for ribosomal proteins or other factors involved in ribosome biogenesis. A hallmark of congenital ribosomopathies is tissue-specific damage and an increased risk of cancer development. In addition, recent research has revealed that somatic mutations in genes for ribosomal proteins are also clinically relevant as they are involved in the process of malignant transformation. In this review article, we describe the pathophysiological effects of ribosome dysfunction at the cellular and molecular level, as well as possible mechanisms promoting oncogenesis. The article also discusses current treatment of ribosomopathies and presents new therapeutic options.
- Klíčová slova
- ribozomopatie,
- MeSH
- biogeneze organel MeSH
- Diamondova-Blackfanova anemie genetika patofyziologie patologie terapie MeSH
- genetické nemoci vrozené farmakoterapie genetika klasifikace patofyziologie terapie MeSH
- krevní nemoci * farmakoterapie genetika klasifikace patofyziologie terapie MeSH
- lidé MeSH
- mutace MeSH
- nádorový supresorový protein p53 MeSH
- ribozomy * patologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
Obstructive sleep apnea (OSA) causes intermittent hypoxia during sleep. Hypoxia predictably initiates an increase in the blood hemoglobin concentration (Hb); yet in our analysis of 527 patients with OSA, >98% did not have an elevated Hb. To understand why patients with OSA do not develop secondary erythrocytosis due to intermittent hypoxia, we first hypothesized that erythrocytosis occurs in these patients, but is masked by a concomitant increase in plasma volume. However, we excluded that explanation by finding that the red cell mass was normal (measured by radionuclide labeling of erythrocytes and carbon monoxide inhalation). We next studied 45 patients with OSA before and after applying continuous positive airway pressure (CPAP). We found accelerated erythropoiesis in these patients (increased erythropoietin and reticulocytosis), but it was offset by neocytolysis (lysis of erythrocytes newly generated in hypoxia upon return to normoxia). Parameters of neocytolysis included increased reactive oxygen species from expanded reticulocytes' mitochondria. The antioxidant catalase was also downregulated in these cells from hypoxia-stimulated microRNA-21. In addition, inflammation-induced hepcidin limited iron availability for erythropoiesis. After CPAP, some of these intermediaries diminished but Hb did not change. We conclude that in OSA, the absence of significant increase in red cell mass is integral to the pathogenesis, and results from hemolysis via neocytolysis combined with inflammation-mediated suppression of erythropoiesis.
- MeSH
- hepcidiny MeSH
- hypoxie MeSH
- lidé MeSH
- obstrukční spánková apnoe * komplikace MeSH
- polycytemie * etiologie MeSH
- reaktivní formy kyslíku MeSH
- zánět MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
Congenital erythrocytoses represent a heterogenous group of rare defects of erythropoiesis characterized by elevated erythrocyte mass. We performed molecular-genetic analysis of 21 Czech patients with congenital erythrocytosis and assessed the mutual link between chronic erythrocyte overproduction and iron homoeostasis. Causative mutations in erythropoietin receptor (EPOR), hypoxia-inducible factor 2 alpha (HIF2A) or Von Hippel-Lindau (VHL) genes were detected in nine patients, including a novel p.A421Cfs*4 EPOR and a homozygous intronic c.340+770T>C VHL mutation. The association and possible cooperation of five identified missense germline EPOR or Janus kinase 2 (JAK2) variants with other genetic/non-genetic factors in erythrocytosis manifestation may involve variants of Piezo-type mechanosensitive ion channel component 1 (PIEZO1) or Ten-eleven translocation 2 (TET2), but this requires further research. In two families, hepcidin levels appeared to prevent or promote phenotypic expression of the disease. No major contribution of heterozygous haemochromatosis gene (HFE) mutations to the erythrocytic phenotype or hepcidin levels was observed in our cohort. VHL- and HIF2A-mutant erythrocytosis showed increased erythroferrone and suppressed hepcidin, whereas no overproduction of erythroferrone was detected in other patients regardless of molecular defect, age or therapy. Understanding the interplay between iron metabolism and erythropoiesis in different subgroups of congenital erythrocytosis may improve current treatment options.
- MeSH
- hepcidiny genetika MeSH
- iontové kanály genetika MeSH
- kyslík metabolismus MeSH
- lidé MeSH
- mutace MeSH
- polycytemie * genetika MeSH
- receptory erythropoetinu genetika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Publikační typ
- abstrakt z konference MeSH
Iron availability for erythropoiesis is controlled by the iron-regulatory hormone hepcidin. Increased erythropoiesis negatively regulates hepcidin synthesis by erythroferrone (ERFE), a hormone produced by erythroid precursors in response to erythropoietin (EPO). The mechanisms coordinating erythropoietic activity with iron homeostasis in erythrocytosis with low EPO are not well defined as exemplified by dominantly inherited (heterozygous) gain-of-function mutation of human EPO receptor (mtHEPOR) with low EPO characterized by postnatal erythrocytosis. We previously created a mouse model of this mtHEPOR that develops fetal erythrocytosis with a transient perinatal amelioration of erythrocytosis and its reappearance at 3-6 weeks of age. Prenatally and perinatally, mtHEPOR heterozygous and homozygous mice (differing in erythrocytosis severity) had increased Erfe transcripts, reduced hepcidin, and iron deficiency. Epo was transiently normal in the prenatal life; then decreased at postnatal day 7, and remained reduced in adulthood. Postnatally, hepcidin increased in mtHEPOR heterozygotes and homozygotes, accompanied by low Erfe induction and iron accumulation. With aging, the old, especially mtHEPOR homozygotes had a decline of erythropoiesis, myeloid expansion, and local bone marrow inflammatory stress. In addition, mtHEPOR erythrocytes had a reduced lifespan. This, together with reduced iron demand for erythropoiesis, due to its age-related attenuation, likely contributes to increased iron deposition in the aged mtHEPOR mice. In conclusion, the erythroid drive-mediated inhibition of hepcidin production in mtHEPOR mice in the prenatal/perinatal period is postnatally abrogated by increasing iron stores promoting hepcidin synthesis. The differences observed in studied characteristics between mtHEPOR heterozygotes and homozygotes suggest dose-dependent alterations of downstream EPOR stimulation.
- MeSH
- aktivační mutace MeSH
- dospělí MeSH
- erythropoetin * genetika farmakologie MeSH
- erytropoéza genetika MeSH
- hepcidiny genetika metabolismus MeSH
- hormony MeSH
- lidé MeSH
- myši MeSH
- polycytemie * genetika MeSH
- receptory erythropoetinu genetika metabolismus MeSH
- senioři MeSH
- železo metabolismus MeSH
- zvířata MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- myši MeSH
- senioři MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Diamond-Blackfan anemia (DBA) is predominantly underlined by mutations in genes encoding ribosomal proteins (RP); however, its etiology remains unexplained in approximately 25 % of patients. We previously reported a novel heterozygous RPS7 mutation hg38 chr2:g.3,580,153G > T p.V134F in one female patient and two asymptomatic family members, in whom mild anemia and increased erythrocyte adenosine deaminase (eADA) activity were detected. We observed that altered erythrocyte metabolism and oxidative stress which may negatively affect the lifespan of erythrocytes distinguishes the patient from her asymptomatic family members. Pathogenicity of the RPS7 p.V134F mutation was extensively validated including molecular defects in protein translational activity and ribosomal stress activation in the cellular model of this variant.
Myeloproliferatívne neoplázie (MPN) tvoria skupinu príbuzných klonálnych hematologických porúch s prekrývajúcim sa fenotypom. Hlavným znakom MPN je nadprodukcia plne diferencovaných myeloidných buniek, chronický zápal a riziko transformácie do sekundárnej akútnej myeloidnej leukémie. Klonálna proliferácia je riadená rôznymi somatickými mutáciami, najčastejšie mutáciami v géne kódujúcom Janusovu kinázu 2 (JAK2). Fenotypová diverzita, špecifická pre MPN, však nemôže prameniť len zo súčinnosti rôznych riadiacich mutácií s mutáciami prídavnými, ktoré sú popisované u pacientov s MPN. Naopak, za heterogenitou MPN stojí celý rad genetických ako aj negenetických faktorov. Ako významný determinant, predovšetkým rozvoja klonálnej hematopoézy, sa ukazuje genetická predispozícia. Náš súhrnný článok prináša prehľad najnovších poznatkov týkajúcich sa komplexnosti patobiológie chromozóm Filadelfia (Ph) -negatívnych MPN.
Myeloproliferative neoplasms (MPNs) represent a group of related clonal haematological disorders with overlapping phenotypes. The main typical features are excessive production of fully differentiated myeloid cells, chronic inflammation and a tendency to transform to acute myeloid leukaemia. Clonal proliferation in MPN is driven by various somatic mutations, most notably involving Janus kinase 2 (JAK2). However, MPN phenotypic diversity cannot be explained only by cooperation of acquired driver mutations with additional somatic mutations detected in MPN patients. Indeed, MPN initiation and clinical phenotype is a product of complex interactions involving both genetic and non-genetic factors. Recently, genetic predisposition appeared as an important determinant of MPN pathophysiology, particularly of clonal expansion. This review provides insights into complex, newly emerging factors contributing to Philadelphia chromosome (Ph) -negative MPN pathobiology.
- MeSH
- chronická myeloidní leukemie etiologie genetika MeSH
- genetická predispozice k nemoci MeSH
- Janus kinasa 2 MeSH
- kalretikulin MeSH
- lidé MeSH
- myeloproliferativní poruchy * genetika MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
Molecular pathophysiology of Diamond-Blackfan anemia (DBA) involves disrupted erythroid-lineage proliferation, differentiation and apoptosis; with the activation of p53 considered as a key component. Recently, oxidative stress was proposed to play an important role in DBA pathophysiology as well. CRISPR/Cas9-created Rpl5- and Rps19-deficient murine erythroleukemia (MEL) cells and DBA patients' samples were used to evaluate proinflammatory cytokines, oxidative stress, DNA damage and DNA damage response. We demonstrated that the antioxidant defense capacity of Rp-mutant cells is insufficient to meet the greater reactive oxygen species (ROS) production which leads to oxidative DNA damage, cellular senescence and activation of DNA damage response signaling in the developing erythroblasts and altered characteristics of mature erythrocytes. We also showed that the disturbed balance between ROS formation and antioxidant defense is accompanied by the upregulation of proinflammatory cytokines. Finally, the alterations detected in the membrane of DBA erythrocytes may cause their enhanced recognition and destruction by reticuloendothelial macrophages, especially during infections. We propose that the extent of oxidative stress and the ability to activate antioxidant defense systems may contribute to high heterogeneity of clinical symptoms and response to therapy observed in DBA patients.
- MeSH
- Diamondova-Blackfanova anemie imunologie metabolismus patologie MeSH
- dítě MeSH
- dospělí MeSH
- erytrocyty metabolismus patologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- mediátory zánětu metabolismus MeSH
- mladý dospělý MeSH
- myši MeSH
- následné studie MeSH
- oxidační stres * MeSH
- poškození DNA * MeSH
- prognóza MeSH
- studie případů a kontrol MeSH
- zánět imunologie metabolismus patologie MeSH
- zvířata MeSH
- Check Tag
- dítě MeSH
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Diamond-Blackfan anemia (DBA) is a rare congenital erythroid aplasia, underlied by haploinsufficient mutations in genes coding for ribosomal proteins (RP) in approximately 70% of cases. DBA is frequently associated with somatic malformations, endocrine dysfunction and with an increased predisposition to cancer. Here we present clinical and genetic characteristics of 62 patients from 52 families enrolled in the Czech and Slovak DBA Registry. Whole exome sequencing (WES) and array comparative genomic hybridization (aCGH) were employed to identify causative mutations in newly diagnosed patients and in cases with previously unrecognized molecular pathology. RP mutation detection rate was 81% (50/62 patients). This included 8 novel point mutations and 4 large deletions encompassing some of the RP genes. Malignant or predisposing condition developed in 8/62 patients (13%): myelodysplastic syndrome in 3 patients; breast cancer in 2 patients; colorectal cancer plus ocular tumor, diffuse large B-cell lymphoma and multiple myeloma each in one case. These patients exclusively harbored RPL5, RPL11 or RPS19 mutations. Array CGH is beneficial for detection of novel mutations in DBA due to its capacity to detect larger chromosomal aberrations. Despite the importance of genotype-phenotype correlation in DBA, phenotypic differences among family members harboring an identical mutation were observed.
- MeSH
- Diamondova-Blackfanova anemie komplikace epidemiologie genetika MeSH
- genetické asociační studie MeSH
- lidé MeSH
- mutace * MeSH
- nádory etiologie MeSH
- registrace MeSH
- ribozomální proteiny genetika MeSH
- rodina MeSH
- sekvenování exomu MeSH
- srovnávací genomová hybridizace MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Česká republika MeSH
- Slovenská republika MeSH
Anémie, zejména sideropenická anémie a anémie chronických chorob, jsou nejčastější extraintestinální systémovou komplikací nespecifických střevních zánětů. U těchto pacientů se často kombinuje relativní deficit železa a chronická zánětlivá aktivita, kdy i přes dostatečné celkové zásoby železa v organismu není železo dostupné pro erytropoézu (tzv. "funkční" deficit železa). Klíčovým regulátorem metabolismu železa je hepcidin a jeho interakce s transmembránovým přenašečem železa feroportinem. Diagnostika a léčba anémie se řídí platnými doporučeními. A aktuální sérová hladina hepcidinu může, vedle ostatních markerů, přispět k rozhodnutí o správné strategii léčby železem (parenterální versus perorální forma).
Anemia is the most common extraintestinal complication of inflammatory bowel disease. Iron deficiency anemia and anemia of chronic disease are the most frequent types. Iron deficiency and chronic inflammation are often combined in patients with inflammatory bowel diseases: total iron body stores are sufficient, but are not available for erytropoiesis (so called "functional" iron deficiency). Hepcidin (interaction of hepcidin-ferroportin) is a key regulator of iron metabolism and also marker of systemic inflammation. Hepcidin binds to ferroportin and blocks its function. The diagnosis and treatment of anemia are guided by available recommendations and the current serum level of hepcidin, in addition to other markers, may contribute to the decision of adequate form of iron supplementation (parenteral versus oral).
