-
Nature Communications Sep 2023Telomerase RNA (TERC) has a noncanonical function in myelopoiesis binding to a consensus DNA binding sequence and attracting RNA polymerase II (RNA Pol II), thus...
Telomerase RNA (TERC) has a noncanonical function in myelopoiesis binding to a consensus DNA binding sequence and attracting RNA polymerase II (RNA Pol II), thus facilitating myeloid gene expression. The CR4/CR5 domain of TERC is known to play this role, since a mutation of this domain found in dyskeratosis congenita (DC) patients decreases its affinity for RNA Pol II, impairing its myelopoietic activity as a result. In this study, we report that two aptamers, short single-stranded oligonucleotides, based on the CR4/CR5 domain were able to increase myelopoiesis without affecting erythropoiesis in zebrafish. Mechanistically, the aptamers functioned as full terc; that is, they increased the expression of master myeloid genes, independently of endogenous terc, by interacting with RNA Pol II and with the terc-binding sequences of the regulatory regions of such genes, enforcing their transcription. Importantly, aptamers harboring the CR4/CR5 mutation that was found in DC patients failed to perform all these functions. The therapeutic potential of the aptamers for treating neutropenia was demonstrated in several preclinical models. The findings of this study have identified two potential therapeutic agents for DC and other neutropenic patients.
Topics: Humans; Animals; Aptamers, Nucleotide; Myelopoiesis; RNA Polymerase II; Syndrome; Zebrafish; Dyskeratosis Congenita
PubMed: 37737237
DOI: 10.1038/s41467-023-41472-7 -
G3 (Bethesda, Md.) Nov 2023Aging is the consequence of intra- and extracellular events that promote cellular senescence. Dyskeratosis congenita (DC) is an example of a premature aging disorder...
Aging is the consequence of intra- and extracellular events that promote cellular senescence. Dyskeratosis congenita (DC) is an example of a premature aging disorder caused by underlying telomere/telomerase-related mutations. Cells from these patients offer an opportunity to study telomere-related aging and senescence. Our previous work has found that telomere shortening stimulates DNA damage responses (DDRs) and increases reactive oxygen species (ROS), thereby promoting entry into senescence. This work also found that telomere elongation via TERT expression, the catalytic component of the telomere-elongating enzyme telomerase, or p53 shRNA could decrease ROS by disrupting this telomere-DDR-ROS pathway. To further characterize this pathway, we performed a CRISPR/Cas9 knockout screen to identify genes that extend life span in DC cells. Of the cellular clones isolated due to increased life span, 34% had a guide RNA (gRNA) targeting CEBPB, while gRNAs targeting WSB1, MED28, and p73 were observed multiple times. CEBPB is a transcription factor associated with activation of proinflammatory response genes suggesting that inflammation may be present in DC cells. The inflammatory response was investigated using RNA sequencing to compare DC and control cells. Expression of inflammatory genes was found to be significantly elevated (P < 0.0001) in addition to a key subset of these inflammation-related genes [IL1B, IL6, IL8, IL12A, CXCL1 (GROa), CXCL2 (GROb), and CXCL5]. which are regulated by CEBPB. Exogenous TERT expression led to downregulation of RNA/protein CEBPB expression and the inflammatory response genes suggesting a telomere length-dependent mechanism to regulate CEBPB. Furthermore, unlike exogenous TERT and p53 shRNA, CEBPB shRNA did not significantly decrease ROS suggesting that CEBPB's contribution in DC cells' senescence is ROS independent. Our findings demonstrate a key role for CEBPB in engaging senescence by mobilizing an inflammatory response within DC cells.
Topics: Humans; Reactive Oxygen Species; Dyskeratosis Congenita; Telomerase; Tumor Suppressor Protein p53; Mutation; Telomere; RNA, Small Interfering; Fibroblasts; Inflammation; Mediator Complex; CCAAT-Enhancer-Binding Protein-beta
PubMed: 37717172
DOI: 10.1093/g3journal/jkad207 -
Annals of Hematology Dec 2023
Topics: Humans; Dyskeratosis Congenita; RNA; Mutation; Telomerase; Telomere
PubMed: 37684378
DOI: 10.1007/s00277-023-05424-x -
Arab Journal of Gastroenterology : the... Aug 2023Previous studies have suggested that lncRNAs impact cancer progression. The lncRNA AC125611.3 (also referred to as RP11-161H23.5) is highly expressed in colon cancer but...
BACKGROUND AND STUDY AIMS
Previous studies have suggested that lncRNAs impact cancer progression. The lncRNA AC125611.3 (also referred to as RP11-161H23.5) is highly expressed in colon cancer but rarely studied; understanding its regulation may provide novel insights on treating colon cancer.
MATERIALS AND METHODS
qRT-PCR was performed to quantify RNAs. CCK-8 and EdU assays were performed to assess cell proliferation. Western blot analysis was used to detect levels of proteins related to cell apoptosis and EMT. Wound healing assay and Transwell invasion assay were conducted to evaluate cell migratory and invasive capabilities, respectively. Luciferase reporter assay, RIP assay, and pull-down assay were used to verify RNA-RNA and RNA-protein interactions.
RESULTS
AC125611.3 was highly overexpressed in colon cancer cells. AC125611.3 depletion curbed cell proliferative, invasive, migratory, and EMT processes while enhancing apoptosis. Furthermore, AC125611.3 activated the Wnt signaling pathway in colon cancer cells by regulating catenin beta-1 (CTNNB1). Moreover, AC125611.3 recruited dyskeratosis congenita 1 (DKC1) to stabilize CTNNB1.
CONCLUSION
AC125611.3 recruits DKC1 to stabilize CTNNB1 and activate Wnt signaling, thereby promoting the progression of colon cancer.
Topics: Humans; Cell Line, Tumor; Dyskeratosis Congenita; Colonic Neoplasms; Wnt Signaling Pathway; RNA, Long Noncoding; Gene Expression Regulation, Neoplastic; Nuclear Proteins; Cell Cycle Proteins; beta Catenin
PubMed: 37684150
DOI: 10.1016/j.ajg.2022.10.013 -
Disease Models & Mechanisms Oct 2023p53 (encoded by Trp53) is a tumor suppressor, but mouse models have revealed that increased p53 activity may cause bone marrow failure, likely through dimerization...
p53 (encoded by Trp53) is a tumor suppressor, but mouse models have revealed that increased p53 activity may cause bone marrow failure, likely through dimerization partner, RB-like, E2F4/E2F5 and MuvB (DREAM) complex-mediated gene repression. Here, we designed a systematic approach to identify p53-DREAM pathway targets, the repression of which might contribute to abnormal hematopoiesis. We used Gene Ontology analysis to study transcriptomic changes associated with bone marrow cell differentiation, then chromatin immunoprecipitation-sequencing (ChIP-seq) data to identify DREAM-bound promoters. We next created positional frequency matrices to identify evolutionary conserved sequence elements potentially bound by DREAM. The same approach was developed to find p53-DREAM targets associated with brain abnormalities, also observed in mice with increased p53 activity. Putative DREAM-binding sites were found for 151 candidate target genes, of which 106 are mutated in a blood or brain genetic disorder. Twenty-one DREAM-binding sites were tested and found to impact gene expression in luciferase assays, to notably regulate genes mutated in dyskeratosis congenita (Rtel1), Fanconi anemia (Fanca), Diamond-Blackfan anemia (Tsr2), primary microcephaly [Casc5 (or Knl1), Ncaph and Wdr62] and pontocerebellar hypoplasia (Toe1). These results provide clues on the role of the p53-DREAM pathway in regulating hematopoiesis and brain development, with implications for tumorigenesis.
Topics: Animals; Mice; Brain; Cell Cycle Proteins; Cyclin-Dependent Kinase Inhibitor p21; Promoter Regions, Genetic; Tumor Suppressor Protein p53
PubMed: 37661832
DOI: 10.1242/dmm.050376 -
Biomolecules Aug 2023Inherited bone marrow failure syndromes (IBMFSs) include Fanconi anemia, Diamond-Blackfan anemia, Shwachman-Diamond syndrome, dyskeratosis congenita, severe congenital... (Review)
Review
Inherited bone marrow failure syndromes (IBMFSs) include Fanconi anemia, Diamond-Blackfan anemia, Shwachman-Diamond syndrome, dyskeratosis congenita, severe congenital neutropenia, and other rare entities such as GATA2 deficiency and SAMD9/9L mutations. The IBMFS monogenic disorders were first recognized by their phenotype. Exome sequencing has validated their classification, with clusters of gene mutations affecting DNA damage response (Fanconi anemia), ribosome structure (Diamond-Blackfan anemia), ribosome assembly (Shwachman-Diamond syndrome), or telomere maintenance/stability (dyskeratosis congenita). The pathogenetic mechanisms of IBMFSs remain to be characterized fully, but an overarching hypothesis states that different stresses elicit TP53-dependent growth arrest and apoptosis of hematopoietic stem, progenitor, and precursor cells. Here, we review the IBMFSs and propose a role for pro-inflammatory cytokines, such as TGF-β, IL-1β, and IFN-α, in mediating the cytopenias. We suggest a pathogenic role for cytokines in the transformation to myeloid neoplasia and hypothesize a role for anti-inflammatory therapies.
Topics: Humans; Congenital Bone Marrow Failure Syndromes; Cytokines; Shwachman-Diamond Syndrome; Dyskeratosis Congenita; Interferon-alpha; Intracellular Signaling Peptides and Proteins
PubMed: 37627314
DOI: 10.3390/biom13081249 -
Frontiers in Pediatrics 2023Dyskeratosis congenita (DC) is a multisystem and ultra-rare hereditary disease characterized by somatic involvement, bone marrow failure, and predisposition to cancer....
BACKGROUND
Dyskeratosis congenita (DC) is a multisystem and ultra-rare hereditary disease characterized by somatic involvement, bone marrow failure, and predisposition to cancer. The main objective of this study is to describe the natural history of DC through a cohort of patients diagnosed in childhood and followed up for a long period of time.
MATERIAL AND METHODS
Multicenter, retrospective, longitudinal study conducted in patients followed up to 24 years since being diagnosed in childhood (between 1998 and 2020).
RESULTS
Fourteen patients were diagnosed with DC between the ages of 3 and 17 years (median, 8.5 years). They all had hematologic manifestations at diagnosis, and nine developed mucocutaneous manifestations during the first decade of life. Seven presented severe DC variants. All developed non-hematologic manifestations during follow-up. Mutations were identified in 12 patients. Thirteen progressed to bone marrow failure at a median age of 8 years [range, 3-18 years], and eight received a hematopoietic stem cell transplant. Median follow-up time was 9 years [range, 2-24 years]. Six patients died, the median age was 13 years [range, 6-24 years]. As of November 2022, eight patients were still alive, with a median age of 18 years [range, 6-32 years]. None of them have developed myeloblastic syndrome or cancer.
CONCLUSIONS
DC was associated with high morbidity and mortality in our series. Hematologic manifestations appeared early and consistently. Non-hematologic manifestations developed progressively. No patient developed cancer possibly due to their young age. Due to the complexity of the disease multidisciplinary follow-up and adequate transition to adult care are essential.
PubMed: 37593443
DOI: 10.3389/fped.2023.1182476 -
Journal Der Deutschen Dermatologischen... Aug 2023
PubMed: 37574687
DOI: 10.1111/ddg.15090_g -
The Journal of Biological Chemistry Sep 2023The levels of non-coding RNAs (ncRNAs) are regulated by transcription, RNA processing, and RNA degradation pathways. One mechanism for the degradation of ncRNAs involves... (Review)
Review
The levels of non-coding RNAs (ncRNAs) are regulated by transcription, RNA processing, and RNA degradation pathways. One mechanism for the degradation of ncRNAs involves the addition of oligo(A) tails by non-canonical poly(A) polymerases, which then recruit processive sequence-independent 3' to 5' exonucleases for RNA degradation. This pathway of decay is also regulated by three 3' to 5' exoribonucleases, USB1, PARN, and TOE1, which remove oligo(A) tails and thereby can protect ncRNAs from decay in a manner analogous to the deubiquitination of proteins. Loss-of-function mutations in these genes lead to premature degradation of some ncRNAs and lead to specific human diseases such as Poikiloderma with Neutropenia (PN) for USB1, Dyskeratosis Congenita (DC) for PARN and Pontocerebellar Hypoplasia type 7 (PCH7) for TOE1. Herein, we review the biochemical properties of USB1, PARN, and TOE1, how they modulate ncRNA levels, and their roles in human diseases.
Topics: Humans; Dyskeratosis Congenita; Exoribonucleases; Neutropenia; RNA Stability; RNA, Untranslated; Loss of Function Mutation
PubMed: 37544646
DOI: 10.1016/j.jbc.2023.105139 -
Seminars in Diagnostic Pathology Nov 2023The diagnostic work up and surveillance of germline disorders of bone marrow failure and predisposition to myeloid malignancy is complex and involves correlation between... (Review)
Review
The diagnostic work up and surveillance of germline disorders of bone marrow failure and predisposition to myeloid malignancy is complex and involves correlation between clinical findings, laboratory and genetic studies, and bone marrow histopathology. The rarity of these disorders and the overlap of clinical and pathologic features between primary and secondary causes of bone marrow failure, acquired aplastic anemia, and myelodysplastic syndrome may result in diagnostic uncertainty. With an emphasis on the pathologist's perspective, we review diagnostically useful features of germline disorders including Fanconi anemia, Shwachman-Diamond syndrome, telomere biology disorders, severe congenital neutropenia, GATA2 deficiency, SAMD9/SAMD9L diseases, Diamond-Blackfan anemia, and acquired aplastic anemia. We discuss the distinction between baseline morphologic and genetic findings of these disorders and features that raise concern for the development of myelodysplastic syndrome.
Topics: Humans; Anemia, Aplastic; Congenital Bone Marrow Failure Syndromes; Bone Marrow Diseases; Pathologists; Myeloproliferative Disorders; Myelodysplastic Syndromes; Bone Marrow Failure Disorders; Germ Cells; Neoplasms; Intracellular Signaling Peptides and Proteins
PubMed: 37507252
DOI: 10.1053/j.semdp.2023.06.006