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Nature Genetics Oct 2019RNA modifications are emerging as key determinants of gene expression. However, compelling genetic demonstrations of their relevance to human disease are lacking. Here,...
RNA modifications are emerging as key determinants of gene expression. However, compelling genetic demonstrations of their relevance to human disease are lacking. Here, we link ribosomal RNA 2'-O-methylation (2'-O-Me) to the etiology of dyskeratosis congenita. We identify nucleophosmin (NPM1) as an essential regulator of 2'-O-Me on rRNA by directly binding C/D box small nucleolar RNAs, thereby modulating translation. We demonstrate the importance of 2'-O-Me-regulated translation for cellular growth, differentiation and hematopoietic stem cell maintenance, and show that Npm1 inactivation in adult hematopoietic stem cells results in bone marrow failure. We identify NPM1 germline mutations in patients with dyskeratosis congenita presenting with bone marrow failure and demonstrate that they are deficient in small nucleolar RNA binding. Mice harboring a dyskeratosis congenita germline Npm1 mutation recapitulate both hematological and nonhematological features of dyskeratosis congenita. Thus, our findings indicate that impaired 2'-O-Me can be etiological to human disease.
Topics: Animals; Dyskeratosis Congenita; Epigenomics; Gene Expression Profiling; Germ-Line Mutation; Hematopoietic Stem Cells; Male; Methylation; Mice; Mice, Inbred C57BL; Mice, Knockout; Nuclear Proteins; Nucleophosmin; RNA Processing, Post-Transcriptional; RNA, Messenger; RNA, Ribosomal; RNA, Small Nucleolar; Transcriptome
PubMed: 31570891
DOI: 10.1038/s41588-019-0502-z -
Genes Sep 2023The highly conserved family of cyclophilins comprises multifunctional chaperones that interact with proteins and RNAs, facilitating the dynamic assembly of...
The highly conserved family of cyclophilins comprises multifunctional chaperones that interact with proteins and RNAs, facilitating the dynamic assembly of multimolecular complexes involved in various cellular processes. Cyclophilin A (CypA), the predominant member of this family, exhibits peptidyl-prolyl cis-trans isomerase activity. This enzymatic function aids with the folding and activation of protein structures and often serves as a molecular regulatory switch for large multimolecular complexes, ensuring appropriate inter- and intra-molecular interactions. Here, we investigated the involvement of CypA in the nucleus, where it plays a crucial role in supporting the assembly and trafficking of heterogeneous ribonucleoproteins (RNPs). We reveal that CypA is enriched in the nucleolus, where it colocalizes with the pseudouridine synthase dyskerin, the catalytic component of the multifunctional H/ACA RNPs involved in the modification of cellular RNAs and telomere stability. We show that dyskerin, whose mutations cause the X-linked dyskeratosis (X-DC) and the Hoyeraal-Hreidarsson congenital ribosomopathies, can directly interact with CypA. These findings, together with the remark that substitution of four dyskerin prolines are known to cause X-DC pathogenic mutations, lead us to indicate this protein as a CypA client. The data presented here suggest that this chaperone can modulate dyskerin activity influencing all its partecipated RNPs.
Topics: Humans; Catalysis; Cyclophilin A; Dyskeratosis Congenita; Ribonucleoproteins; RNA-Binding Proteins
PubMed: 37761906
DOI: 10.3390/genes14091766 -
Hematology. American Society of... Dec 2020Advances in the diagnosis and treatment of inherited bone marrow failure syndromes (IBMFS) have provided insight into the complexity of these diseases. The diseases are... (Review)
Review
Advances in the diagnosis and treatment of inherited bone marrow failure syndromes (IBMFS) have provided insight into the complexity of these diseases. The diseases are heterogeneous and characterized by developmental abnormalities, progressive marrow failure, and predisposition to cancer. A correct diagnosis allows for appropriate treatment, genetic counseling, and cancer surveillance. The common IBMFSs are Fanconi anemia, dyskeratosis congenita, and Diamond-Blackfan anemia. Hematopoietic cell transplantation (HCT) offers curative treatment of the hematologic complications of IBMFS. Because of the systemic nature of these diseases, transplant strategies are modified to decrease immediate and late toxicities. HCT from HLA-matched related or unrelated donors offers excellent survival for young patients in aplasia. Challenges include the treatment of adults with marrow aplasia, presentation with myeloid malignancy regardless of age, and early detection or treatment of cancer. In this article, I will describe our approach and evaluation of patients transplanted with IBMFS and review most frequent complications before and after transplant.
Topics: Age Factors; Allografts; Congenital Bone Marrow Failure Syndromes; Disease-Free Survival; Hematologic Neoplasms; Hematopoietic Stem Cell Transplantation; Humans; Neoplastic Syndromes, Hereditary; Survival Rate
PubMed: 33275667
DOI: 10.1182/hematology.2020000095 -
Frontiers in Oncology 2023Replication Protein A (RPA) is single-strand DNA binding protein that plays a key role in the replication and repair of DNA. RPA is a heterotrimer made of 3 subunits -...
Replication Protein A (RPA) is single-strand DNA binding protein that plays a key role in the replication and repair of DNA. RPA is a heterotrimer made of 3 subunits - RPA1, RPA2, and RPA3. Germline pathogenic variants affecting were recently described in patients with Telomere Biology Disorders (TBD), also known as dyskeratosis congenita or short telomere syndrome. Premature telomere shortening is a hallmark of TBD and results in bone marrow failure and predisposition to hematologic malignancies. Building on the finding that somatic mutations in RPA subunit genes occur in ~1% of cancers, we hypothesized that germline RPA alterations might be enriched in human cancers. Because germline mutations are linked to early onset TBD with predisposition to myelodysplastic syndromes, we interrogated pediatric cancer cohorts to define the prevalence and spectrum of rare/novel and putative damaging germline , , and variants. In this study of 5,993 children with cancer, 75 (1.25%) harbored heterozygous rare (non-cancer population allele frequency (AF) < 0.1%) variants in the RPA heterotrimer genes, of which 51 cases (0.85%) had ultra-rare (AF < 0.005%) or novel variants. Compared with Genome Aggregation Database (gnomAD) non-cancer controls, there was significant enrichment of ultra-rare and novel , but not or , germline variants in our cohort (adjusted p-value < 0.05). Taken together, these findings suggest that germline putative damaging variants affecting are found in excess in children with cancer, warranting further investigation into the functional role of these variants in oncogenesis.
PubMed: 37869077
DOI: 10.3389/fonc.2023.1229507 -
British Journal of Haematology May 2021Dyskeratosis Congenita (DKC) is a systemic disorder caused by mutations resulting in impaired telomere maintenance. Clinical features include bone marrow failure and an...
Dyskeratosis Congenita (DKC) is a systemic disorder caused by mutations resulting in impaired telomere maintenance. Clinical features include bone marrow failure and an increased risk of developing hematological malignancies. There are conflicting data whether androgen derivatives (AD) can elongate telomeres in vivo and whether AD treatment enhances the risk of gaining myelodysplastic syndrome-related mutations. Seven TERC or TERT-mutated DKC patients underwent AD treatment. All patients revealed hematological response. Telomere length of lymphocytes and granulocytes increased significantly and no MDS-related mutations were detected. Pending longer follow-up, treatment with AD seems to represent an efficient and safe therapy for DKC patients.
Topics: Adult; Androgens; Blood Cell Count; Dyskeratosis Congenita; Female; Follow-Up Studies; Humans; Male; Middle Aged; Mutation; Myelodysplastic Syndromes; RNA; Telomerase; Telomere; Telomere Homeostasis
PubMed: 32744739
DOI: 10.1111/bjh.16997 -
International Journal of Molecular... Jun 2020Inherited bone marrow failure syndromes (IBMFS) are a group of cancer-prone genetic diseases characterized by hypocellular bone marrow with impairment in one or more... (Review)
Review
Inherited bone marrow failure syndromes (IBMFS) are a group of cancer-prone genetic diseases characterized by hypocellular bone marrow with impairment in one or more hematopoietic lineages. The pathogenesis of IBMFS involves mutations in several genes which encode for proteins involved in DNA repair, telomere biology and ribosome biogenesis. The classical IBMFS include Shwachman-Diamond syndrome (SDS), Diamond-Blackfan anemia (DBA), Fanconi anemia (FA), dyskeratosis congenita (DC), and severe congenital neutropenia (SCN). IBMFS are associated with high risk of myelodysplastic syndrome (MDS), acute myeloid leukemia (AML), and solid tumors. Unfortunately, no specific pharmacological therapies have been highly effective for IBMFS. Hematopoietic stem cell transplantation provides a cure for aplastic or myeloid neoplastic complications. However, it does not affect the risk of solid tumors. Since approximately 28% of FA, 24% of SCN, 21% of DBA, 20% of SDS, and 17% of DC patients harbor nonsense mutations in the respective IBMFS-related genes, we discuss the use of the nonsense suppression therapy in these diseases. We recently described the beneficial effect of ataluren, a nonsense suppressor drug, in SDS bone marrow hematopoietic cells ex vivo. A similar approach could be therefore designed for treating other IBMFS. In this review we explain in detail the new generation of nonsense suppressor molecules and their mechanistic roles. Furthermore, we will discuss strengths and limitations of these molecules which are emerging from preclinical and clinical studies. Finally we discuss the state-of-the-art of preclinical and clinical therapeutic studies carried out for IBMFS.
Topics: Aminoglycosides; Codon, Nonsense; Congenital Bone Marrow Failure Syndromes; Humans; Nonsense Mediated mRNA Decay; Oxadiazoles
PubMed: 32630050
DOI: 10.3390/ijms21134672 -
RNA (New York, N.Y.) Dec 2021Dyskerin and its homologs are ancient and conserved enzymes that catalyze the most common post-transcriptional modification found in cells, pseudouridylation. The... (Review)
Review
Dyskerin and its homologs are ancient and conserved enzymes that catalyze the most common post-transcriptional modification found in cells, pseudouridylation. The resulting pseudouridines provide stability to RNA molecules and regulate ribosome biogenesis and splicing events. Dyskerin does not act independently-it is the core component of a protein heterotetramer, which associates with RNAs that contain the H/ACA motif. The variety of H/ACA RNAs that guide the function of this ribonucleoprotein (RNP) complex highlights the diversity of cellular processes in which dyskerin participates. When associated with small nucleolar (sno) RNAs, it regulates ribosomal (r) RNAs and ribosome biogenesis. By interacting with small Cajal body (sca) RNAs, it targets small nuclear (sn) RNAs to regulate pre-mRNA splicing. As a component of the telomerase holoenzyme, dyskerin binds to the telomerase RNA to modulate telomere maintenance. In a disease context, dyskerin malfunction can result in multiple detrimental phenotypes. Mutations in , the gene that encodes dyskerin, cause the premature aging syndrome X-linked dyskeratosis congenita (X-DC), a still incurable disorder that typically leads to bone marrow failure. In this review, we present the classical and most recent findings on this essential protein, discussing the evolutionary, structural, and functional aspects of dyskerin and the H/ACA RNP. The latest research underscores the role that dyskerin plays in the regulation of gene expression, translation efficiency, and telomere maintenance, along with the impacts that defective dyskerin has on aging, cell proliferation, haematopoietic potential, and cancer.
Topics: Alternative Splicing; Cell Cycle Proteins; Dyskeratosis Congenita; Humans; Intramolecular Transferases; Mutation; Nuclear Proteins; RNA Processing, Post-Transcriptional; Ribosomes; Telomere
PubMed: 34556550
DOI: 10.1261/rna.078953.121 -
Leukemia Jun 2024Recent advances in in-depth data-independent acquisition proteomic analysis have enabled comprehensive quantitative analysis of >10,000 proteins. Herein, an integrated...
Recent advances in in-depth data-independent acquisition proteomic analysis have enabled comprehensive quantitative analysis of >10,000 proteins. Herein, an integrated proteogenomic analysis for inherited bone marrow failure syndrome (IBMFS) was performed to reveal their biological features and to develop a proteomic-based diagnostic assay in the discovery cohort; dyskeratosis congenita (n = 12), Fanconi anemia (n = 11), Diamond-Blackfan anemia (DBA, n = 9), Shwachman-Diamond syndrome (SDS, n = 6), ADH5/ALDH2 deficiency (n = 4), and other IBMFS (n = 18). Unsupervised proteomic clustering identified eight independent clusters (C1-C8), with the ribosomal pathway specifically downregulated in C1 and C2, enriched for DBA and SDS, respectively. Six patients with SDS had significantly decreased SBDS protein expression, with two of these not diagnosed by DNA sequencing alone. Four patients with ADH5/ALDH2 deficiency showed significantly reduced ADH5 protein expression. To perform a large-scale rapid IBMFS screening, targeted proteomic analysis was performed on 417 samples from patients with IBMFS-related hematological disorders (n = 390) and healthy controls (n = 27). SBDS and ADH5 protein expressions were significantly reduced in SDS and ADH5/ALDH2 deficiency, respectively. The clinical application of this first integrated proteogenomic analysis would be useful for the diagnosis and screening of IBMFS, where appropriate clinical screening tests are lacking.
Topics: Humans; Bone Marrow Failure Disorders; Proteogenomics; Male; Female; Bone Marrow Diseases; Child; Adult; Adolescent; Child, Preschool; Anemia, Diamond-Blackfan; Young Adult; Fanconi Anemia; Proteomics; Infant; Shwachman-Diamond Syndrome; Dyskeratosis Congenita
PubMed: 38740980
DOI: 10.1038/s41375-024-02263-1 -
Stem Cell Research & Therapy Jan 2021Dyskeratosis congenita (DC) is a rare telomere biology disorder, which results in different clinical manifestations, including severe bone marrow failure. To date, the...
Dyskeratosis congenita (DC) is a rare telomere biology disorder, which results in different clinical manifestations, including severe bone marrow failure. To date, the only curative treatment for the bone marrow failure in DC patients is allogeneic hematopoietic stem cell transplantation. However, due to the toxicity associated to this treatment, improved therapies are recommended for DC patients. Here, we aimed at generating DC-like human hematopoietic stem cells in which the efficacy of innovative therapies could be investigated. Because X-linked DC is the most frequent form of the disease and is associated with an impaired expression of DKC1, we have generated DC-like hematopoietic stem cells based on the stable knock-down of DKC1 in human CD34 cells with lentiviral vectors encoding for DKC1 short hairpin RNAs. At a molecular level, DKC1-interfered CD34 cells showed a decreased expression of TERC, as well as a diminished telomerase activity and increased DNA damage, cell senescence, and apoptosis. Moreover, DKC1-interfered human CD34 cells showed defective clonogenic ability and were incapable of repopulating the hematopoiesis of immunodeficient NSG mice. The development of DC-like hematopoietic stem cells will facilitate the understanding of the molecular and cellular basis of this inherited bone marrow failure syndrome and will serve as a platform to evaluate the efficacy of new hematopoietic therapies for DC.
Topics: Animals; Cell Cycle Proteins; Dyskeratosis Congenita; Hematopoietic Stem Cells; Humans; Mice; Mutation; Nuclear Proteins; Telomerase; Telomere
PubMed: 33514435
DOI: 10.1186/s13287-021-02145-8 -
JAAD Case Reports Nov 2022
PubMed: 36275875
DOI: 10.1016/j.jdcr.2022.09.011