RESUMEN

RATIONALE: Fanconi anemia (FA) is a hereditary disease caused by mutations in the genes involved in the DNA damage repair pathway. The FANCA gene is the most commonly pathogenic gene, accounting for more than 60% of all causative genes. PATIENT CONCERNS: The clinical case is a 3-year-old boy showed mild anemia and scattered bleeding spots the size of a needle tip all over his body. DIAGNOSES: Compound heterozygous mutation was identified in the FANCA gene in the FA case: c.1A > T from the father in exon 1; the deletion of chr16: 89857810-89858476 (exon13-14 del) from the mother; finally, the patient was diagnosed as Fanconi anemia. INTERVENTION: After diagnosis, the child received chemotherapy (Ara-C + Flu + Cy + ATG). Then, the hematopoietic stem cell transplantation and unrelated umbilical cord blood transfusion were performed. OUTCOMES: The child is recovering well and is in regular follow-up. CONCLUSION AND LESSONS: The discovery of new mutations in the FANCA gene enriches the genetic profile of FA and helps clinicians to further understand this disease and guide genetic counseling and prenatal diagnosis. Whole-exome sequencing is a powerful tool for diagnosing FA.

Asunto(s)

Proteína del Grupo de Complementación A de la Anemia de Fanconi , Anemia de Fanconi , Humanos , Anemia de Fanconi/genética , Anemia de Fanconi/complicaciones , Anemia de Fanconi/diagnóstico , Proteína del Grupo de Complementación A de la Anemia de Fanconi/genética , Masculino , Preescolar , Mutación , Trasplante de Células Madre Hematopoyéticas

RESUMEN

During the repair of interstrand crosslinks (ICLs) a DNA double-strand break (DSB) is generated. The Fanconi anemia (FA) core complex, which is recruited to ICLs, promotes high-fidelity repair of this DSB by homologous recombination (HR). However, whether the FA core complex also promotes HR at ICL-independent DSBs, for example induced by ionizing irradiation or nucleases, remains controversial. Here, we identified the FA core complex members FANCL and Ube2T as HR-promoting factors in a CRISPR/Cas9-based screen. Using isogenic cell line models, we further demonstrated an HR-promoting function of FANCL and Ube2T, and of their ubiquitination substrate FANCD2. We show that FANCL and Ube2T localize at DSBs in a FANCM-dependent manner, and are required for the DSB accumulation of FANCD2. Mechanistically, we demonstrate that FANCL ubiquitin ligase activity is required for the accumulation of CtIP at DSBs, thereby promoting end resection and Rad51 loading. Together, these data demonstrate a dual genome maintenance function of the FA core complex and FANCD2 in promoting repair of both ICLs and DSBs.

Asunto(s)

Roturas del ADN de Doble Cadena , Proteína del Grupo de Complementación D2 de la Anemia de Fanconi , Proteína del Grupo de Complementación L de la Anemia de Fanconi , Recombinación Homóloga , Enzimas Ubiquitina-Conjugadoras , Humanos , Proteína del Grupo de Complementación D2 de la Anemia de Fanconi/metabolismo , Proteína del Grupo de Complementación D2 de la Anemia de Fanconi/genética , Proteína del Grupo de Complementación L de la Anemia de Fanconi/metabolismo , Proteína del Grupo de Complementación L de la Anemia de Fanconi/genética , Enzimas Ubiquitina-Conjugadoras/metabolismo , Enzimas Ubiquitina-Conjugadoras/genética , Proteínas Nucleares/metabolismo , Proteínas Nucleares/genética , Proteínas Portadoras/metabolismo , Proteínas Portadoras/genética , Sistemas CRISPR-Cas , Ubiquitinación , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Endodesoxirribonucleasas/metabolismo , Endodesoxirribonucleasas/genética , Células HEK293 , Reparación del ADN por Recombinación , Reparación del ADN , Reparación del ADN por Unión de Extremidades , ADN Helicasas

RESUMEN

Histone lysine methyltransferase 2D (KMT2D) is the most frequently mutated epigenetic modifier in head and neck squamous cell carcinoma (HNSCC). However, the role of KMT2D in HNSCC tumorigenesis and whether its mutations confer any therapeutic vulnerabilities remain unknown. Here we show that KMT2D deficiency promotes HNSCC growth through increasing glycolysis. Additionally, KMT2D loss decreases the expression of Fanconi Anemia (FA)/BRCA pathway genes under glycolytic inhibition. Mechanistically, glycolytic inhibition facilitates the occupancy of KMT2D to the promoter/enhancer regions of FA genes. KMT2D loss reprograms the epigenomic landscapes of FA genes by transiting their promoter/enhancer states from active to inactive under glycolytic inhibition. Therefore, combining the glycolysis inhibitor 2-DG with DNA crosslinking agents or poly (ADP-ribose) polymerase (PARP) inhibitors preferentially inhibits tumor growth of KMT2D-deficient mouse HNSCC and patient-derived xenografts (PDXs) harboring KMT2D-inactivating mutations. These findings provide an epigenomic basis for developing targeted therapies for HNSCC patients with KMT2D-inactivating mutations.

Asunto(s)

Glucólisis , Carcinoma de Células Escamosas de Cabeza y Cuello , Animales , Humanos , Ratones , Glucólisis/genética , Carcinoma de Células Escamosas de Cabeza y Cuello/genética , Carcinoma de Células Escamosas de Cabeza y Cuello/tratamiento farmacológico , Carcinoma de Células Escamosas de Cabeza y Cuello/metabolismo , Carcinoma de Células Escamosas de Cabeza y Cuello/patología , Línea Celular Tumoral , Proteínas de Unión al ADN/metabolismo , Proteínas de Unión al ADN/genética , Proteína BRCA1/metabolismo , Proteína BRCA1/genética , Proteína BRCA1/deficiencia , Proteína BRCA2/genética , Proteína BRCA2/metabolismo , Proteína BRCA2/deficiencia , N-Metiltransferasa de Histona-Lisina/metabolismo , N-Metiltransferasa de Histona-Lisina/genética , Neoplasias de Cabeza y Cuello/genética , Neoplasias de Cabeza y Cuello/metabolismo , Neoplasias de Cabeza y Cuello/tratamiento farmacológico , Neoplasias de Cabeza y Cuello/patología , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Regulación Neoplásica de la Expresión Génica , Ensayos Antitumor por Modelo de Xenoinjerto , Inhibidores de Poli(ADP-Ribosa) Polimerasas/farmacología , Femenino , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Transducción de Señal , Regiones Promotoras Genéticas/genética , Proteína de la Leucemia Mieloide-Linfoide

RESUMEN

Fanconi Anaemia is an autosomal recessive disorder, which is characterised by progressive pancytopenia, café au lait spots (>50%), bruising, petechie, recurrent infections, short height (50%), and thumb and radial bone anomalies (40%). Herein, is presented a case of a lean emaciated female child, who presented with the chief complaints of fever, loose stools and decreased appetite for one month reported at Sindh Government General Hospital, Karachi, on February, 1, 2023. She had cutaneous findings of hyperpigmentation and café au lait spots and a tri-phalangeal thumb. On investigation, pancytopenia and a low reticulocyte count of 0.7% was also observed. Karyotype and chromosomal breakage test induced by Diepoxybutane confirmed her as a case of Fanconi Anaemia.

Asunto(s)

Manchas Café con Leche , Anemia de Fanconi , Humanos , Femenino , Anemia de Fanconi/complicaciones , Anemia de Fanconi/diagnóstico , Anemia de Fanconi/genética , Manchas Café con Leche/genética , Rotura Cromosómica , Compuestos Epoxi

RESUMEN

Fanconi anemia (FA) is a hereditary disorder characterized by a deficiency in the repair of DNA interstrand crosslinks and the response to replication stress. Endogenous DNA damage, most likely caused by aldehydes, severely affects hematopoietic stem cells in FA, resulting in progressive bone marrow failure and the development of leukemia. Recent studies revealed that expression levels of SLFN11 affect the replication stress response and are a strong determinant in cell killing by DNA-damaging cancer chemotherapy. Because SLFN11 is highly expressed in the hematopoietic system, we speculated that SLFN11 may have a significant role in FA pathophysiology. Indeed, we found that DNA damage sensitivity in FA cells is significantly mitigated by the loss of SLFN11 expression. Mechanistically, we demonstrated that SLFN11 destabilizes the nascent DNA strands upon replication fork stalling. In this review, we summarize our work regarding an interplay between SLFN11 and the FA pathway, and the role of SLFN11 in the response to replication stress.

Asunto(s)

Daño del ADN , Replicación del ADN , Anemia de Fanconi , Proteínas Nucleares , Anemia de Fanconi/metabolismo , Anemia de Fanconi/genética , Humanos , Proteínas Nucleares/metabolismo , Proteínas Nucleares/genética , Animales , Reparación del ADN , Proteínas del Grupo de Complementación de la Anemia de Fanconi/metabolismo , Proteínas del Grupo de Complementación de la Anemia de Fanconi/genética

RESUMEN

Fanconi anemia (FA) is an inherited disorder of DNA repair due to mutation in one of 20+ interrelated genes that repair intrastrand DNA crosslinks and rescue collapsed or stalled replication forks. The most common hematologic abnormality in FA is anemia, but progression to bone marrow failure (BMF), clonal hematopoiesis, or acute myeloid leukemia may also occur. In prior studies, we found that Fanconi DNA repair is required for successful emergency granulopoiesis; the process for rapid neutrophil production during the innate immune response. Specifically, Fancc-/- mice did not develop neutrophilia in response to emergency granulopoiesis stimuli, but instead exhibited apoptosis of bone marrow hematopoietic stem cells and differentiating neutrophils. Repeated emergency granulopoiesis challenges induced BMF in most Fancc-/- mice, with acute myeloid leukemia in survivors. In contrast, we found equivalent neutrophilia during emergency granulopoiesis in Fancc-/-Tp53+/- mice and WT mice, without BMF. Since termination of emergency granulopoiesis is triggered by accumulation of bone marrow neutrophils, we hypothesize neutrophilia protects Fancc-/-Tp53+/- bone marrow from the stress of a sustained inflammation that is experienced by Fancc-/- mice. In the current work, we found that blocking neutrophil accumulation during emergency granulopoiesis led to BMF in Fancc-/-Tp53+/- mice, consistent with this hypothesis. Blocking neutrophilia during emergency granulopoiesis in Fancc-/-Tp53+/- mice (but not WT) impaired cell cycle checkpoint activity, also found in Fancc-/- mice. Mechanisms for loss of cell cycle checkpoints during infectious disease challenges may define molecular markers of FA progression, or suggest therapeutic targets for bone marrow protection in this disorder.

Asunto(s)

Proteína del Grupo de Complementación C de la Anemia de Fanconi , Anemia de Fanconi , Células Madre Hematopoyéticas , Ratones Noqueados , Neutrófilos , Animales , Anemia de Fanconi/patología , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Neutrófilos/metabolismo , Neutrófilos/patología , Ratones , Células Madre Hematopoyéticas/metabolismo , Células Madre Hematopoyéticas/patología , Proteína del Grupo de Complementación C de la Anemia de Fanconi/genética , Proteína del Grupo de Complementación C de la Anemia de Fanconi/metabolismo , Proteína p53 Supresora de Tumor/metabolismo , Proteína p53 Supresora de Tumor/genética , Hematopoyesis , Ratones Endogámicos C57BL , Médula Ósea/metabolismo , Médula Ósea/patología

RESUMEN

The twenty-three Fanconi anemia (FA) proteins cooperate in the FA/BRCA pathway to repair DNA interstrand cross-links (ICLs). The cell division cycle and apoptosis regulator 1 (CCAR1) protein is also a regulator of ICL repair, though its possible function in the FA/BRCA pathway remains unknown. Here, we demonstrate that CCAR1 plays a unique upstream role in the FA/BRCA pathway and is required for FANCA protein expression in human cells. Interestingly, CCAR1 co-immunoprecipitates with FANCA pre-mRNA and is required for FANCA mRNA processing. Loss of CCAR1 results in retention of a poison exon in the FANCA transcript, thereby leading to reduced FANCA protein expression. A unique domain of CCAR1, the EF hand domain, is required for interaction with the U2AF heterodimer of the spliceosome and for excision of the poison exon. Taken together, CCAR1 is a splicing modulator required for normal splicing of the FANCA mRNA and other mRNAs involved in various cellular pathways.

Asunto(s)

Proteínas Reguladoras de la Apoptosis , Proteínas de Ciclo Celular , Proteína del Grupo de Complementación A de la Anemia de Fanconi , Anemia de Fanconi , Empalme del ARN , Factor de Empalme U2AF , Humanos , Proteína BRCA1/metabolismo , Proteína BRCA1/genética , Proteína BRCA2/metabolismo , Proteína BRCA2/genética , Reparación del ADN , Endodesoxirribonucleasas , Exones , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Proteína del Grupo de Complementación A de la Anemia de Fanconi/genética , Proteína del Grupo de Complementación A de la Anemia de Fanconi/metabolismo , Células HEK293 , Células HeLa , Unión Proteica , Precursores del ARN/metabolismo , Precursores del ARN/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , Transducción de Señal , Empalmosomas/metabolismo , Empalmosomas/genética , Factor de Empalme U2AF/metabolismo , Factor de Empalme U2AF/genética , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas Reguladoras de la Apoptosis/genética , Proteínas Reguladoras de la Apoptosis/metabolismo

RESUMEN

In this issue of Molecular Cell, Harada et al.1 and Karasu et al.2 identify CCAR1 as a novel regulator of the Fanconi anemia/BRCA DNA repair pathway via modulating the splicing of the mRNA encoding FANCA.

Asunto(s)

Reparación del ADN , Empalme del ARN , Humanos , Proteína del Grupo de Complementación A de la Anemia de Fanconi/genética , Proteína del Grupo de Complementación A de la Anemia de Fanconi/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Proteína BRCA1/genética , Proteína BRCA1/metabolismo

RESUMEN

Objective: Infertility affects approximately one-sixth of the people of childbearing age worldwide, causing not only economic burdens of treatment for families with fertility problems but also psychological stress for patients and presenting challenges to societal and economic development. Premature ovarian insufficiency (POI) refers to the loss of ovarian function in women before the age of 40 due to the depletion of follicles or decreased quality of remaining follicles, constituting a significant cause of female infertility. In recent years, with the help of the rapid development in genetic sequencing technology, it has been demonstrated that genetic factors play a crucial role in the onset of POI. Among the population suffering from POI, genetic studies have revealed that genes involved in processes such as meiosis, DNA damage repair, and mitosis account for approximately 37.4% of all pathogenic and potentially pathogenic genes identified. FA complementation group M (FANCM) is a group of genes involved in the damage repair of DNA interstrand crosslinks (ICLs), including FANCA-FANCW. Abnormalities in the FANCM genes are associated with female infertility and FANCM gene knockout mice also exhibit phenotypes similar to those of POI. During the genetic screening of POI patients, this study identified a suspicious variant in FANCM. This study aims to explore the pathogenic mechanisms of the FANCM genes of the FA pathway and their variants in the development of POI. We hope to help shed light on potential diagnostic and therapeutic strategies for the affected individuals. Methods: One POI patient was included in the study. The inclusion criteria for POI patients were as follows: women under 40 years old exhibiting two or more instances of basal serum follicle-stimulating hormone levels>25 IU/L (with a minimum interval of 4 weeks inbetween tests), alongside clinical symptoms of menstrual disorders, normal chromosomal karyotype analysis results, and exclusion of other known diseases that can lead to ovarian dysfunction. We conducted whole-exome sequencing for the POI patient and identified pathogenic genes by classifying variants according to the standards and guidelines established by the American College of Medical Genetics and Genomics (ACMG). Subsequently, the identified variants were validated through Sanger sequencing and subjected to bioinformatics analysis. Plasmids containing wild-type and mutant FANCM genes were constructed and introduced into 293T cells. The 293T cells transfected with wild-type and mutant human FANCM plasmids and pEGFP-C1 empty vector plasmids were designated as the EGFP FANCM-WT group, the EGFP FANCM-MUT group, and the EGFP group, respectively. To validate the production of truncated proteins, cell proteins were extracted 48 hours post-transfection from the three groups and confirmed using GFP antibody. In order to investigate the impact on DNA damage repair, immunofluorescence experiments were conducted 48 hours post-transfection in the EGFP FANCM-WT group and the EGFP FANCM-MUT group to examine whether the variant affected FANCM's ability to localize on chromatin. Mitomycin C was used to induce ICLs damage in vitro in both the EGFP FANCM-WT group and the EGFP FANCM-MUT group, which was followed by verification of its effect on ICLs damage repair using γ-H2AX antibody. Results: In a POI patient from a consanguineous family, we identified a homozygous variant in the FANCM gene, c.1152-1155del:p.Leu386Valfs*10. The patient presented with primary infertility, experiencing irregular menstruation since menarche at the age of 16. Hormonal evaluation revealed an FSH level of 26.79 IU/L and an anti-Müllerian hormone (AMH) level of 0.07 ng/mL. Vaginal ultrasound indicated unsatisfactory visualization of the ovaries on both sides and uterine dysplasia. The patient's parents were a consanguineous couple, with the mother having regular menstrual cycles. The patient had two sisters, one of whom passed away due to osteosarcoma, while the other exhibited irregular menstruation, had been diagnosed with ovarian insufficiency, and remained childless. Bioinformatics analysis revealed a deletion of four nucleotides (c.1152-1155del) in the exon 6 of the patient's FANCM gene. This variant resulted in a frameshift at codon 386, introducing a premature stop codon at codon 396, which ultimately led to the production of a truncated protein consisting of 395 amino acids. In vitro experiments demonstrated that this variant led to the production of a truncated FANCM protein of approximately 43 kDa and caused a defect in its nuclear localization, with the protein being present only in the cytoplasm. Following treatment with mitomycin C, there was a significant increase in γ-H2AX levels in 293T cells transfected with the mutant plasmid (P<0.01), indicating a statistically significant impairment of DNA damage repair capability caused by this variant. Conclusions: The homozygous variant in the FANCM gene, c.1152-1155del:p.Leu386Valfs*10, results in the production of a truncated FANCM protein. This truncation leads to the loss of its interaction site with the MHF1-MHF2 complex, preventing its entry into the nucleus and the subsequent recognition of DNA damage. Consequently, the localization of the FA core complex on chromatin is disrupted, impeding the normal activation of the FA pathway and reducing the cell's ability to repair damaged ICLs. By disrupting the rapid proliferation and meiotic division processes of primordial germ cells, the reserve of oocytes is depleted, thereby triggering premature ovarian insufficiency in females.

Asunto(s)

Insuficiencia Ovárica Primaria , Femenino , Insuficiencia Ovárica Primaria/genética , Humanos , Mutación , Anemia de Fanconi/genética , Adulto , Infertilidad Femenina/genética , Infertilidad Femenina/etiología , ADN Helicasas

RESUMEN

Fanconi anemia, a rare disorder with an incidence of 1 in 300,000, is caused by mutations in FANC genes, which affect the repair of DNA interstrand crosslinks. The disease is characterized by congenital malformations, bone marrow failure within the first decade of life, and recurrent squamous cell carcinomas of the oral cavity, esophagus, and anogenital regions starting around age 20. In this review, we propose that Fanconi anemia should be considered a premature-aging syndrome. Interestingly, the onset and severity of the life-limiting clinical features of Fanconi anemia can be influenced by lifestyle choices, such as a healthy diet and physical activity. These factors shape the epigenetic status of at-risk cell types and enhance the competence of the immune system through nutritional signaling. Fanconi anemia may serve as a model for understanding the aging process in the general population, addressing research gaps in its clinical presentation and suggesting prevention strategies. Additionally, we will discuss how the balance of genetic and environmental risk factors-affecting both cancer onset and the speed of aging-is interlinked with signal transduction by dietary molecules. The underlying nutrigenomic principles will offer guidance for healthy aging in individuals with Fanconi anemia as well as for the general population.

Asunto(s)

Anemia de Fanconi , Nutrigenómica , Humanos , Anemia de Fanconi/genética , Envejecimiento Prematuro/genética , Epigénesis Genética , Factores de Riesgo

RESUMEN

Some years ago, we reported the generation of a Fanconi anemia (FA) microRNA signature. This study aims to develop an analytical strategy to select a smaller and more reliable set of molecules that could be tested for potential benefits for the FA phenotype, elucidate its biochemical and molecular mechanisms, address experimental activity, and evaluate its possible impact on FA therapy. In silico analyses of the data obtained in the original study were thoroughly processed and anenrichment analysis was employed to identify the classes of genes that are over-represented in the FA-miRNA population under study. Primary bone marrow mononuclear cells (MNCs) from sixFA patients and sixhealthy donors as control samples were employed in the study. RNAs containing the small RNA fractions were reverse-transcribed and real-time PCR was performed in triplicate using the specific primers. Experiments were performed in triplicate.The in-silico analysis reported six miRNAs as likely contributors to the complex pathological spectrum of FA. Among these, three miRNAs were validated by real-time PCR. Primary bone marrow mononuclear cells (MNCs) reported a significant reduction in the expression level of miRNA-1246 and miRNA-206 in the FA samples in comparison to controls.This study highlights several biochemical pathways as culprits in the phenotypic manifestations and the pathophysiological mechanisms acting in FA. A relatively low number of miRNAs appear involved in all these different phenotypes, demonstrating the extreme plasticity of the gene expression modulation. This study further highlights miR-206 as a pivotal player in regulatory functions and signaling in the bone marrow mesenchymal stem cell (BMSC) process in FA. Due to this evidence, the activity of miR-206 in FA deserves specific experimental scrutiny. The results, here presented, might be relevant in the management of FA.

Asunto(s)

Anemia de Fanconi , MicroARNs , MicroARNs/genética , Anemia de Fanconi/genética , Humanos , Masculino , Células de la Médula Ósea/metabolismo , Femenino , Niño , Perfilación de la Expresión Génica/métodos

RESUMEN

DNA repair is directly performed by hundreds of core factors and indirectly regulated by thousands of others. We massively expanded a CRISPR inhibition and Cas9-editing screening system to discover factors indirectly modulating homology-directed repair (HDR) in the context of ∼18,000 individual gene knockdowns. We focused on CCAR1, a poorly understood gene that we found the depletion of reduced both HDR and interstrand crosslink repair, phenocopying the loss of the Fanconi anemia pathway. CCAR1 loss abrogated FANCA protein without substantial reduction in the level of its mRNA or that of other FA genes. We instead found that CCAR1 prevents inclusion of a poison exon in FANCA. Transcriptomic analysis revealed that the CCAR1 splicing modulatory activity is not limited to FANCA, and it instead regulates widespread changes in alternative splicing that would damage coding sequences in mouse and human cells. CCAR1 therefore has an unanticipated function as a splicing fidelity factor.

Asunto(s)

Empalme Alternativo , Proteína del Grupo de Complementación A de la Anemia de Fanconi , Humanos , Animales , Ratones , Proteína del Grupo de Complementación A de la Anemia de Fanconi/genética , Proteína del Grupo de Complementación A de la Anemia de Fanconi/metabolismo , Reparación del ADN por Recombinación , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Células HEK293 , Exones , Sistemas CRISPR-Cas , Reparación del ADN , Células HeLa , Daño del ADN

RESUMEN

Genomic instability is not only a hallmark of senescent cells but also a key factor driving cellular senescence, and replication stress is the main source of genomic instability. Defective prelamin A processing caused by lamin A/C (LMNA) or zinc metallopeptidase STE24 (ZMPSTE24) gene mutations results in premature aging. Although previous studies have shown that dysregulated lamin A interferes with DNA replication and causes replication stress, the relationship between lamin A dysfunction and replication stress remains largely unknown. Here, an increase in baseline replication stress and genomic instability is found in prelamin A-expressing cells. Moreover, prelamin A confers hypersensitivity of cells to exogenous replication stress, resulting in decreased cell survival and exacerbated genomic instability. These effects occur because prelamin A promotes MRE11-mediated resection of stalled replication forks. Fanconi anemia (FA) proteins, which play important roles in replication fork maintenance, are downregulated by prelamin A in a retinoblastoma (RB)/E2F-dependent manner. Additionally, prelamin A inhibits the activation of the FA pathway upon replication stress. More importantly, FA pathway downregulation is an upstream event of p53-p21 axis activation during the induction of prelamin A expression. Overall, these findings highlight the critical role of FA pathway dysfunction in driving replication stress-induced genomic instability and cellular senescence in prelamin A-expressing cells.

Asunto(s)

Replicación del ADN , Inestabilidad Genómica , Lamina Tipo A , Inestabilidad Genómica/genética , Lamina Tipo A/genética , Lamina Tipo A/metabolismo , Humanos , Replicación del ADN/genética , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Senescencia Celular/genética

Asunto(s)

Proteína del Grupo de Complementación A de la Anemia de Fanconi , Anemia de Fanconi , Mutación , Fenotipo , Hermanos , Humanos , Anemia de Fanconi/genética , Anemia de Fanconi/diagnóstico , Proteína del Grupo de Complementación A de la Anemia de Fanconi/genética , Masculino , Femenino , Predisposición Genética a la Enfermedad , Análisis Mutacional de ADN , Piel/patología , Niño

RESUMEN

Fanconi anemia (FA) is an autosomal or X-linked human disease, characterized by bone marrow failure, cancer susceptibility and various developmental abnormalities. So far, at least 22 FA genes (FANCA-W) have been identified. Germline inactivation of any one of these FA genes causes FA symptoms. Proteins encoded by FA genes are involved in the Fanconi anemia pathway, which is known for its roles in DNA inter-strand crosslinks (ICLs) repair. Besides, its roles in genome maintenance upon replication stress has also been reported. Post-translational modifications (PTMs) of FA proteins, particularly phosphorylation and ubiquitination, emerge as critical determinants in the activation of the FA pathway during ICL repair or replication stress response. Consequent inactivation of the FA pathway engenders heightened chromosomal instability, thereby constituting a genetic susceptibility conducive to cancer predisposition and the exacerbation of tumorigenesis. In this review, we have combined recent structural analysis of FA proteins and summarized knowledge on the functions of different PTMs in regulating FA pathways, and discuss potential contributions stemming from mutations at PTMs to the genesis and progression of tumorigenesis.

Asunto(s)

Proteínas del Grupo de Complementación de la Anemia de Fanconi , Procesamiento Proteico-Postraduccional , Humanos , Proteínas del Grupo de Complementación de la Anemia de Fanconi/metabolismo , Proteínas del Grupo de Complementación de la Anemia de Fanconi/genética , Carcinogénesis/metabolismo , Carcinogénesis/genética , Anemia de Fanconi/metabolismo , Anemia de Fanconi/genética , Animales , Reparación del ADN

RESUMEN

Premature ovarian insufficiency is a common form of female infertility affecting up to 4% of women and characterised by amenorrhea with elevated gonadotropin before the age of 40. Oocytes require controlled DNA breakage and repair for homologous recombination and the maintenance of oocyte integrity. Biallelic disruption of the DNA damage repair gene, Fanconi anemia complementation group A (FANCA), is a common cause of Fanconi anaemia, a syndrome characterised by bone marrow failure, cancer predisposition, physical anomalies and POI. There is ongoing dispute about the role of heterozygous FANCA variants in POI pathogenesis, with insufficient evidence supporting causation. Here, we have identified biallelic FANCA variants in French sisters presenting with POI, including a novel missense variant of uncertain significance and a likely pathogenic deletion that initially evaded detection. Functional studies indicated no discernible effect on DNA damage sensitivity in patient lymphoblasts. These novel FANCA variants add evidence that heterozygous loss of one allele is insufficient to cause DNA damage sensitivity and POI. We propose that intragenic deletions, that are relatively common in FANCA, may be missed without careful analysis, and could explain the presumed causation of heterozygous variants. Accurate variant curation is critical to optimise patient care and outcomes.

Asunto(s)

Alelos , Proteína del Grupo de Complementación A de la Anemia de Fanconi , Insuficiencia Ovárica Primaria , Humanos , Insuficiencia Ovárica Primaria/genética , Femenino , Proteína del Grupo de Complementación A de la Anemia de Fanconi/genética , Adulto , Anemia de Fanconi/genética , Anemia de Fanconi/diagnóstico , Hermanos , Heterocigoto , Predisposición Genética a la Enfermedad , Linaje , Mutación/genética

Asunto(s)

Anemia de Fanconi , Leucemia Eritroblástica Aguda , Humanos , Anemia de Fanconi/genética , Anemia de Fanconi/complicaciones , Anemia de Fanconi/diagnóstico , Leucemia Eritroblástica Aguda/genética , Leucemia Eritroblástica Aguda/patología , Leucemia Eritroblástica Aguda/diagnóstico , Cariotipo Anormal , Masculino , Transformación Celular Neoplásica/genética , Transformación Celular Neoplásica/patología , Niño , Preescolar

RESUMEN

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.

Asunto(s)

Enfermedades de la Médula Ósea , Trastornos de Fallo de la Médula Ósea , Proteogenómica , Humanos , Trastornos de Fallo de la Médula Ósea/genética , Trastornos de Fallo de la Médula Ósea/patología , Proteogenómica/métodos , Masculino , Femenino , Enfermedades de la Médula Ósea/genética , Enfermedades de la Médula Ósea/patología , Niño , Adulto , Adolescente , Preescolar , Anemia de Diamond-Blackfan/genética , Anemia de Diamond-Blackfan/diagnóstico , Adulto Joven , Anemia de Fanconi/genética , Anemia de Fanconi/diagnóstico , Proteómica/métodos , Lactante , Síndrome de Shwachman-Diamond/genética , Disqueratosis Congénita/genética , Disqueratosis Congénita/diagnóstico , Disqueratosis Congénita/patología

RESUMEN

Anti-CD117 monoclonal antibody (mAb) agents have emerged as exciting alternative conditioning strategies to traditional genotoxic irradiation or chemotherapy for both allogeneic and autologous gene-modified hematopoietic stem cell transplantation. Furthermore, these agents are concurrently being explored in the treatment of mast cell disorders. Despite promising results in animal models and more recently in patients, the short- and long-term effects of these treatments have not been fully explored. We conducted rigorous assessments to evaluate the effects of an antagonistic anti-mCD117 mAb, ACK2, on hematopoiesis in wild-type and Fanconi anemia (FA) mice. Importantly, we found no evidence of short-term DNA damage in either setting following this treatment, suggesting that ACK2 does not induce immediate genotoxicity, providing crucial insights into its safety profile. Surprisingly, FA mice exhibited an increase in colony formation after ACK2 treatment, indicating a potential targeting of hematopoietic stem cells and expansion of hematopoietic progenitor cells. Moreover, the long-term phenotypic and functional changes in hematopoietic stem and progenitor cells did not differ significantly between the ACK2-treated and control groups, in either setting, suggesting that ACK2 does not adversely affect hematopoietic capacity. These findings underscore the safety of these agents when utilized as a short-course treatment in the context of conditioning, as they did not induce significant DNA damage in hematopoietic stem or progenitor cells. However, single-cell RNA sequencing, used to compare gene expression between untreated and treated mice, revealed that the ACK2 mAb, via c-Kit downregulation, effectively modulated the MAPK pathway with Fos downregulation in wild-type and FA mice. Importantly, this modulation was achieved without causing prolonged disruptions. These findings validate the safety of anti-CD117 mAb treatment and also enhance our understanding of its intricate mode of action at the molecular level.

Asunto(s)

Anticuerpos Monoclonales , Anemia de Fanconi , Hematopoyesis , Células Madre Hematopoyéticas , Proteínas Proto-Oncogénicas c-kit , Animales , Ratones , Proteínas Proto-Oncogénicas c-kit/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-kit/genética , Hematopoyesis/efectos de los fármacos , Anticuerpos Monoclonales/farmacología , Anticuerpos Monoclonales/uso terapéutico , Anemia de Fanconi/terapia , Anemia de Fanconi/genética , Células Madre Hematopoyéticas/efectos de los fármacos , Células Madre Hematopoyéticas/metabolismo , Células Madre Hematopoyéticas/citología , Modelos Animales de Enfermedad , Daño del ADN/efectos de los fármacos

RESUMEN

The complementation Q group (FANCQ) subtype of Fanconi anemia (FA) caused by the ERCC4/XPF mutation is very rare. Two siblings, aged 13 and 10 with Fanconi phenotypic features, presented with right hemiparesis and focal-onset seizures. In both cases, cranial magnetic resonance imaging (MRI) showed mass-like lesions accompanied by peripheral edema and calcification. In one case, oral steroid treatment and surgical excision were performed, while in the other case, the cranial lesion regressed just with steroid treatment and without surgery. Both siblings remained wheelchair-bound due to neurological dysfunction. One case died due to hepatocellular carcinoma. ERCC4/XPF gene mutation was detected in both siblings.

Asunto(s)

Proteínas de Unión al ADN , Anemia de Fanconi , Hermanos , Humanos , Anemia de Fanconi/complicaciones , Anemia de Fanconi/genética , Anemia de Fanconi/patología , Masculino , Proteínas de Unión al ADN/genética , Niño , Adolescente , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patología , Neoplasias Encefálicas/complicaciones , Femenino , Imagen por Resonancia Magnética , Mutación , Diagnóstico Diferencial