Tethering Apo2L/TRAIL to the surface of lipid nanoparticles greatly increases its bioactivity and could be of potential use in anti-tumor therapeutics.
Background
Telomeres are nucleoprotein structures present at the terminal region of the chromosomes. Mutations in genes coding for proteins involved in telomere maintenance are causative of a number of disorders known as telomeropathies. The genetic origin of these diseases is heterogeneous and has not been determined for a significant proportion of patients.
Methods
This article describes the genetic characterization of a cohort of patients. Telomere length was determined by Southern blot and quantitative PCR. Nucleotide variants were analyzed either by high-resolution melting analysis and Sanger sequencing of selected exons or by massive sequencing of a panel of genes.
Results
Forty-seven patients with telomere length below the 10% of normal population, affected with three telomeropathies: dyskeratosis congenita (4), aplastic anemia (22) or pulmonary fibrosis (21) were analyzed. Eighteen of these patients presented known pathogenic or novel possibly pathogenic variants in the telomere-related genes
TERT
,
TERC
,
RTEL1
,
CTC1
and
ACD
. In addition, the analyses of a panel of 188 genes related to haematological disorders indicated that a relevant proportion of the patients (up to 35%) presented rare variants in genes related to DNA repair or in genes coding for proteins involved in the resolution of complex DNA structures, that participate in telomere replication. Mutations in some of these genes are causative of several syndromes previously associated to telomere shortening.
Conclusion
Novel variants in telomere, DNA repair and replication genes are described that might indicate the contribution of variants in these genes to the development of telomeropathies. Patients carrying variants in telomere-related genes presented worse evolution after diagnosis than the rest of patients analyzed.
Electronic supplementary material
The online version of this article (10.1186/s13023-019-1046-0) contains supplementary material, which is available to authorized users.
GATA binding protein 2 (GATA2) deficiency is a rare disorder of hematopoiesis, lymphatics, and immunity caused by spontaneous or autosomal dominant mutations in the GATA2 gene. Clinical manifestations range from neutropenia, lymphedema, deafness, to severe viral and mycobacterial infections, bone marrow failure, and acute myeloid leukemia. Patients also present with monocytopenia, dendritic cell, B- and natural killer (NK)-cell deficiency. We studied the T-cell and NK-cell compartments of four GATA2-deficient patients to assess if changes in these lymphocyte populations could be correlated with clinical phenotype. Patients with more severe clinical complications demonstrated a senescent T-cell phenotype whereas patients with lower clinical score had undetectable changes relative to controls. In contrast, patients’ NK-cells demonstrated an immature/activated phenotype that did not correlate with clinical score, suggesting an intrinsic NK-cell defect. These studies will help us to determine the contribution of T- and NK-cell dysregulation to the clinical phenotype of GATA2 patients, and may help to establish the most accurate therapeutic options for these patients. Asymptomatic patients may be taken into consideration for hematopoietic stem cell transplantation when dysregulation of T-cell and NK-cell compartment is present.
Pearson syndrome (PS) is a rare multisystem disease caused by single large scale mitochondrial DNA deletions (SLSMDs). PS presents early in infancy and it is mainly characterized by refractory sideroblastic anaemia. Prognosis is poor and treatment is supportive, thus development of new models for the study of PS and new therapy strategies is essential. In this work we report three different cell models carrying a SLMSD: fibroblasts, transmitochondrial cybrids and induced pluripotent stem cells (iPSC). All studied models exhibited an aberrant mitochondrial ultrastructure and defective OXPHOS function, showing a decrease in different parameters such as mitochondrial ATP, respiratory complex IV activity and quantity or oxygen consumption. Despite that, iPSC harbouring “common deletion” were able to differentiate into three germ layers. Besides, cybrids clones only showed mitochondrial dysfunction when heteroplasmy level reached 70%. Some differences observed among models may depend on their metabolic profile, therefore we consider these three models are useful for the in vitro study of the PS as well as for testing new specific therapies.
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