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1.
Arq Neuropsiquiatr ; 82(5): 1-8, 2024 May.
Article in English | MEDLINE | ID: mdl-38763144

ABSTRACT

BACKGROUND: Neuronal ceroid lipofuscinoses (NCL) are a group of autosomal recessive, inherited, lysosomal, and neurodegenerative diseases that causes progressive dementia, seizures, movement disorders, language delay/regression, progressive visual failure, and early death. Neuronal ceroid lipofuscinosis type 2 (CLN2), caused by biallelic pathogenic variants of the TPP1 gene, is the only NCL with an approved targeted therapy. The laboratory diagnosis of CLN2 is established through highly specific tests, leading to diagnostic delays and eventually hampering the provision of specific treatment for patients with CLN2. Epilepsy is a common and clinically-identifiable feature among NCLs, and seizure onset is the main driver for families to seek medical care. OBJECTIVE: To evaluate the results of the Latin America Epilepsy and Genetics Program, an epilepsy gene panel, as a comprehensive tool for the investigation of CLN2 among other genetic causes of epilepsy. METHODS: A total of 1,284 patients with epilepsy without a specific cause who had at least 1 symptom associated with CLN2 were screened for variants in 160 genes associated with epilepsy or metabolic disorders presenting with epilepsy through an epilepsy gene panel. RESULTS: Variants of the TPP1 gene were identified in 25 individuals (1.9%), 21 of them with 2 variants. The 2 most frequently reported variants were p.Arg208* and p.Asp276Val, and 2 novel variants were detected in the present study: p.Leu308Pro and c.89 + 3G > C Intron 2. CONCLUSION: The results suggest that these genetic panels can be very useful tools to confirm or exclude CLN2 diagnosis and, if confirmed, provide disease-specific treatment for the patients.


ANTECEDENTES: As lipofuscinoses ceroides neuronais (neuronal ceroid lipofuscinoses, NCLs, em inglês) são um grupo de doenças autossômicas recessivas, hereditárias, lisossomais e neurodegenerativas que causam demência progressiva, crises epiléticas, distúrbios de movimento, atraso/regressão da linguagem, deficiência visual progressiva e morte precoce. A lipofuscinose ceroide neuronal tipo 2 (neuronal ceroid lipofuscinosis type 2, CLN2, em inglês), causada por variantes patogênicas bialélicas do gene TPP1, é a única com terapia-alvo aprovada. O diagnóstico laboratorial é realizado por testes específicos, o que leva a atrasos diagnósticos e, consequentemente, prejudica a disponibilização de tratamento. A epilepsia é uma característica comum e clinicamente identificável entre as NCLs, e o início das convulsões é o principal motivo para as famílias buscarem atendimento médico. OBJETIVO: Avaliar os resultados do Programa de Epilepsia e Genética da América Latina, um painel genético, como uma ferramenta abrangente para a investigação de CLN2 entre outras causas genéticas de epilepsia. MéTODOS: Um total de 1.284 pacientes com epilepsia sem uma causa específica e que tinham pelo menos 1 sintoma associado à CLN2 foram rastreados em busca de variantes em 160 genes associados à epilepsia ou a distúrbios metabólicos que apresentam epilepsia, por meio de um painel genético. RESULTADOS: Variantes do gene TPP1 foram identificadas em 25 indivíduos (1,9%), sendo que ; 21 apresentavam duas variantes. As duas variantes mais frequentes foram p.Arg208* e p.Asp276Val, e duas variantes novas foram detectadas neste: p.Leu308Pro e c.89 + 3G > C Intron 2. CONCLUSãO: Os resultados sugerem que os painéis genéticos de epilepsia podem ser uma ferramenta útil para confirmar ou excluir o diagnóstico de CLN2 e, se confirmado, fornecer tratamento específico para os pacientes.


Subject(s)
Aminopeptidases , Epilepsy , Neuronal Ceroid-Lipofuscinoses , Serine Proteases , Tripeptidyl-Peptidase 1 , Humans , Neuronal Ceroid-Lipofuscinoses/genetics , Female , Male , Epilepsy/genetics , Aminopeptidases/genetics , Serine Proteases/genetics , Child , Adolescent , Adult , Young Adult , Child, Preschool , Telomere-Binding Proteins/genetics , Dipeptidyl-Peptidases and Tripeptidyl-Peptidases/genetics , Mutation , Genetic Testing/methods , Middle Aged , Infant
2.
J Med Genet ; 60(7): 692-696, 2023 07.
Article in English | MEDLINE | ID: mdl-36539277

ABSTRACT

Pathogenic germline variants in the protection of telomeres 1 gene (POT1) have been associated with predisposition to a range of tumour types, including melanoma, glioma, leukaemia and cardiac angiosarcoma. We sequenced all coding exons of the POT1 gene in 2928 European-descent melanoma cases and 3298 controls, identifying 43 protein-changing genetic variants. We performed POT1-telomere binding assays for all missense and stop-gained variants, finding nine variants that impair or disrupt protein-telomere complex formation, and we further define the role of variants in the regulation of telomere length and complex formation through molecular dynamics simulations. We determine that POT1 coding variants are a minor contributor to melanoma burden in the general population, with only about 0.5% of melanoma cases carrying germline pathogenic variants in this gene, but should be screened in individuals with a strong family history of melanoma and/or multiple malignancies.


Subject(s)
Melanoma , Skin Neoplasms , Humans , Melanoma/genetics , Skin Neoplasms/genetics , Shelterin Complex , Telomere-Binding Proteins/genetics , Telomere/metabolism , Case-Control Studies , Melanoma, Cutaneous Malignant
3.
J Exp Med ; 219(5)2022 05 02.
Article in English | MEDLINE | ID: mdl-35420632

ABSTRACT

Exonic sequencing identified a family with idiopathic pulmonary fibrosis (IPF) containing a previously unreported heterozygous mutation in POT1 p.(L259S). The family displays short telomeres and genetic anticipation. We found that POT1(L259S) is defective in binding the telomeric overhang, nuclear accumulation, negative regulation of telomerase, and lagging strand maintenance. Patient cells containing the mutation display telomere loss, lagging strand defects, telomere-induced DNA damage, and premature senescence with G1 arrest. Our data suggest POT1(L259S) is a pathogenic driver of IPF and provide insights into gene therapy options.


Subject(s)
Idiopathic Pulmonary Fibrosis , Telomerase , Humans , Idiopathic Pulmonary Fibrosis/genetics , Shelterin Complex , Telomerase/genetics , Telomerase/metabolism , Telomere/genetics , Telomere/metabolism , Telomere-Binding Proteins/genetics
4.
Horm Res Paediatr ; 94(11-12): 448-455, 2021.
Article in English | MEDLINE | ID: mdl-34706368

ABSTRACT

Coats plus syndrome is an autosomal recessive multisystemic and pleiotropic disorder affecting the eyes, brain, bone, and gastrointestinal tract, usually caused by compound heterozygous variants of the conserved telomere maintenance component 1 gene (CTC1), involved in telomere homeostasis and replication. So far, most reported patients are compound heterozygous for a truncating mutation and a missense variant. The phenotype is believed to result from telomere dysfunction, with accumulation of DNA damage, cellular senescence, and stem cell depletion. Here, we report a 23-year-old female with prenatal and postnatal growth retardation, microcephaly, osteopenia, recurrent fractures, intracranial calcification, leukodystrophy, parenchymal brain cysts, bicuspid aortic valve, and primary ovarian failure. She carries a previously reported maternally inherited pathogenic variant in exon 5 (c.724_727del, p.(Lys242Leufs*41)) and a novel, paternally inherited splice site variant (c.1617+5G>T; p.(Lys480Asnfs*17)) in intron 9. CTC1 transcript analysis showed that the latter resulted in skipping of exon 9. A trace of transcripts was normally spliced resulting in the presence of a low level of wild-type CTC1 transcripts. We speculate that ovarian failure is caused by telomere shortening or chromosome cohesion failure in oocytes and granulosa cells, with early decrease in follicular reserve. This is the first patient carrying 2 truncating CTC1 variants and the first presenting primary ovarian failure.


Subject(s)
Calcinosis , Central Nervous System Cysts , Leukoencephalopathies , Ataxia/genetics , Ataxia/pathology , Brain Neoplasms , Calcinosis/genetics , Central Nervous System Cysts/genetics , Central Nervous System Cysts/pathology , Female , Humans , Leukoencephalopathies/genetics , Leukoencephalopathies/pathology , Muscle Spasticity , Mutation , Retinal Diseases , Seizures , Telomere-Binding Proteins/genetics
5.
J Egypt Natl Canc Inst ; 33(1): 24, 2021 Sep 06.
Article in English | MEDLINE | ID: mdl-34486082

ABSTRACT

BACKGROUND: Telomere dysfunction is one of the hallmarks of cancer and is crucial to prostate carcinogenesis. TERF1 is a gene essential to telomere maintenance, and its dysfunction has already been associates with several cancers. TERF1 is a target of miR-155, and this microRNA can inhibit its expression and promotes carcinogenesis in breast cancer. We aim to analyze TERF1, in gene and mRNA level, involvement in prostate cancer progression. RESULTS: Alterations in TERF1 DNA were evaluated using datasets of primary tumor and castration-resistant tumors (CRPC) deposited in cBioportal. The expression of TERF1 mRNA levels was assessed utilizing TCGA datasets, clinical specimens, and metastatic prostate cancer cell lines (LNCaP, DU145, and PC3). Six percent of localized prostate cancer presents alterations in TERF1 (the majority of that was amplifications). In the CRPC cohort, 26% of samples had TERF1 amplification. Patients with TERF1 alterations had the worst overall survival only on localized cancer cohort (p = 0.0027). In the TCGA cohort, mRNA levels of TERF1 were downregulated in comparison with normal tissue (p = 0.0013) and upregulated in tumors that invade lymph nodes (p = 0.0059). The upregulation of TERF1 is also associated with worst overall survival (p = 0.0028) and disease-free survival (p = 0.0023). There is a positive correlation between TERF1 and androgen receptor expression in cancer tissue (r = 0.53, p < 0.00001) but not on normal tissue (r = - 0.16, p = 0.12). In the clinical specimens, there is no detectable expression of TERF1 and upregulation of miR-155 (p = 0.0348). In cell lines, TERF1 expression was higher in LNCaP and was progressively lower in DU145 and PC3 (p = 0.0327) with no differences in miR-155 expression. CONCLUSION: Amplification/upregulation of TERF1 was associated with the worst prognostic in localized prostate cancer. Our results corroborate that miR-155 regulates TERF1 expression in prostate cancer. TERF1 has the potential to become a biomarker in prostate cancer.


Subject(s)
MicroRNAs , Prostatic Neoplasms , Telomere-Binding Proteins/genetics , Cell Line, Tumor , Gene Expression Regulation, Neoplastic , Humans , Male , MicroRNAs/genetics , Prognosis , Prostatic Neoplasms/genetics , Shelterin Complex
6.
Int J Sports Med ; 42(3): 283-290, 2021 Mar.
Article in English | MEDLINE | ID: mdl-32947637

ABSTRACT

Aging muscle is prone to sarcopenia and its associated telomere shortening and increased oxidative stress. Telomeres are protected by a shelterin protein complex, proteins expressed in response to DNA damage. Aerobic exercise training has shown to positively modulate these proteins while aging, but the effects of resistance training are less clear. This investigation was to examine the role of dynamic and isometric RT on markers of senescence and muscle apoptosis: checkpoint kinase 2, 53 kDa protein, shelterin telomere repeat binding 1 and 2, DNA repair, telomere length and redox state in the quadriceps muscle. Fifteen 49-week-old male rats were divided into three groups: control, dynamic resistance training, and isometric resistance training. Dynamic and isometric groups completed five sessions per week during 16 weeks at low to moderate intensity (20-70% maximal load). Only dynamic group decreased expression of 53 kDa protein, proteins from shelterin complex, oxidative stress, and improved antioxidant defense. There was no difference among groups regarding telomere length. In conclusion, dynamic resistance training was more effective than isometric in reducing markers of aging and muscle apoptosis in elderly rats. This modality should be considered as valuable tool do counteract the deleterious effects of aging.


Subject(s)
Aging/physiology , Muscle, Skeletal/metabolism , Muscle, Skeletal/physiology , Resistance Training/methods , Animals , Apoptosis , Biomarkers/metabolism , Checkpoint Kinase 2/metabolism , DNA Repair , Genes, p53 , Isometric Contraction , Male , Muscle, Skeletal/cytology , Oxidation-Reduction , Oxidative Stress , Physical Conditioning, Animal , Rats, Wistar , Telomere Shortening , Telomere-Binding Proteins/physiology
7.
Genes (Basel) ; 11(7)2020 07 21.
Article in English | MEDLINE | ID: mdl-32708340

ABSTRACT

Telomere maintenance mechanisms (TMM) are used by cancer cells to avoid apoptosis, 85-90% reactivate telomerase, while 10-15% use the alternative lengthening of telomeres (ALT). Due to anti-telomerase-based treatments, some tumors switch from a telomerase-dependent mechanism to ALT; in fact, the co-existence between both mechanisms has been observed in some cancers. Although different elements in the ALT pathway are uncovered, some molecular mechanisms are still poorly understood. Therefore, with the aim to identify potential molecular markers for the study of ALT, we combined in silico approaches in a 411 telomere maintenance gene set. As a consequence, we conducted a genomic analysis of these genes in 31 Pan-Cancer Atlas studies from The Cancer Genome Atlas and found 325,936 genomic alterations; from which, we identified 20 genes highly mutated in the cancer studies. Finally, we made a protein-protein interaction network and enrichment analysis to observe the main pathways of these genes and discuss their role in ALT-related processes, like homologous recombination and homology directed repair. Overall, due to the lack of understanding of the molecular mechanisms of ALT cancers, we proposed a group of genes, which after ex vivo validations, could represent new potential therapeutic markers in the study of ALT.


Subject(s)
Neoplasms/genetics , Telomere Homeostasis , Genetic Predisposition to Disease , Humans , Neoplasms/metabolism , Protein Interaction Maps , Telomere-Binding Proteins/genetics , Telomere-Binding Proteins/metabolism
8.
Exp Mol Pathol ; 112: 104354, 2020 02.
Article in English | MEDLINE | ID: mdl-31837325

ABSTRACT

In the past decade, research efforts were made to identify molecular biomarkers useful as therapeutic targets in Non-Small Cell Lung Cancer (NSCLC), the most frequent type of lung carcinoma. NSCLC presents different histological subtypes being the most prevalent LUSC (Lung Squamous Cell Cancer) and LUAD (Lung Adenocarcinoma), and only a subset of LUAD patients' present tumors expressing known targetable genetic alterations. Telomeres and its components, including telomerase, the enzyme that replenishes telomeres, have been considered potential cancer biomarkers due to their crucial role in cell proliferation and genome stability. Our study aims to quantify expression changes affecting telomere-associated genes and ncRNAs associated with telomere regulation and maintenance in NSCLC. We first assessed the transcriptome (RNA-Seq) data of NSCLC patients from The Cancer Genome Atlas (TCGA) and then we tested the expression of telomere-associated genes and telomeric ncRNAs (TERC, telomerase RNA component, and TERRA, telomere repeat-containing RNA) in Brazilian NCSLC patient samples by quantitative RT-PCR, using matched normal adjacent tissue samples as the control. We also estimated the mean size of terminal restriction fragments (TRF) of some Brazilian NSCLC patients using telomeric Southern blot. The TCGA analysis identified alterations in the expression profile of TERT and telomere damage repair genes, mainly in the LUSC subtype. The study of Brazilian NSCLC samples by RT-qPCR showed that LUSC and LUAD express high amounts of TERT and that although the mean TRF size of tumor samples was shorter compared to normal cells, telomeres in NSCLC are probably maintained by telomerase. Also, the expression analysis of Brazilian NSCLC samples identified statistically significant alterations in the expression of genes involved with telomere damage repair, as well as in TERC and TERRA, mainly in the LUSC subtype. We, therefore, concluded that telomere maintenance genes are significantly deregulated in NSCLC, representing potential biomarkers in the LUSC subtype.


Subject(s)
Adenocarcinoma/genetics , Carcinoma, Non-Small-Cell Lung/genetics , Neoplasms, Squamous Cell/genetics , Telomere/genetics , Adenocarcinoma/classification , Adenocarcinoma/pathology , Biomarkers, Tumor/genetics , Brazil , Carcinoma, Non-Small-Cell Lung/classification , Carcinoma, Non-Small-Cell Lung/pathology , Cell Cycle Proteins/genetics , Cell Proliferation/genetics , DNA-Binding Proteins/genetics , Gene Expression Regulation, Neoplastic/genetics , Humans , Neoplasms, Squamous Cell/classification , Neoplasms, Squamous Cell/pathology , Nuclear Proteins/genetics , RNA/genetics , RNA, Long Noncoding/genetics , Shelterin Complex , Telomerase/genetics , Telomere-Binding Proteins/genetics , Transcription Factors/genetics , Transcriptome/genetics
9.
Mol Genet Genomic Med ; 6(6): 1148-1156, 2018 11.
Article in English | MEDLINE | ID: mdl-30393977

ABSTRACT

BACKGROUND: Cerebroretinal microangiopathy with calcifications and cysts (CRMCC) is an autosomal recessive disorder caused by pathogenic variants of the conserved telomere maintenance component 1 (CTC1) gene. The CTC1 forms the telomeric capping complex, CST, which functions in telomere homeostasis and replication. METHODS: A Brazilian pedigree and an Australian pedigree were referred to the International Registry of Werner Syndrome (Seattle, WA, USA), with clinical features of accelerated aging and recurrent bone fractures. Whole exome sequencing was performed to identify the genetic causes. RESULTS: Whole exome sequencing of the Brazilian pedigree revealed compound heterozygous pathogenic variants in CTC1: a missense mutation (c.2959C>T, p.Arg987Trp) and a novel stop codon change (c.322C>T, p.Arg108*). The Australian patient carried two novel heterozygous CTC1 variants, c.2916G>T, p.Val972Gly and c.2926G>T, p.Val976Phe within the same allele. Both heterozygous variants were inherited from the unaffected father, excluding the diagnosis of CRMCC in this pedigree. Cell biological studies demonstrated accumulation of double strand break foci in lymphoblastoid cell lines derived from the patients. Increased DSB foci were extended to non-telomeric regions of the genome, in agreement with previous biochemical studies showing a preferential binding of CTC1 protein to GC-rich sequences. CONCLUSION: CTC1 pathogenic variants can present with unusual manifestations of progeria accompanied with recurrent bone fractures. Further studies are needed to elucidate the disease mechanism leading to the clinical presentation with intra-familial variations of CRMCC.


Subject(s)
Fractures, Bone/genetics , Mutation , Phenotype , Telomere-Binding Proteins/genetics , Werner Syndrome/genetics , Adult , Cell Line , DNA Breaks, Double-Stranded , Female , Fractures, Bone/pathology , GC Rich Sequence , Genomic Instability , Humans , Male , Middle Aged , Pedigree , Protein Binding , Telomere/genetics , Telomere-Binding Proteins/metabolism , Werner Syndrome/pathology
10.
Article in English | MEDLINE | ID: mdl-30333961

ABSTRACT

Telomeric Repeat Binding Factors (TRFs) are architectural nuclear proteins with critical roles in telomere-length regulation, chromosome end protection and, fusion prevention, DNA damage detection, and senescence regulation. Entamoeba histolytica, the parasite responsible of human amoebiasis, harbors three homologs of human TRFs, based on sequence similarities to their Myb DNA binding domain. These proteins were dubbed EhTRF-like I, II and III. In this work, we revealed that EhTRF-like I and II share similarity with human TRF1, while EhTRF-like III shares similarity with human TRF2 by in silico approach. The analysis of ehtrf-like genes showed they are expressed differentially under basal culture conditions. We also studied the cellular localization of EhTRF-like I and III proteins using subcellular fractionation and western blot assays. EhTRF-like I and III proteins were enriched in the nuclear fraction, but they were also present in the cytoplasm. Indirect immunofluorescence showed that these proteins were located at the nuclear periphery co-localizing with Lamin B1 and trimethylated H4K20, which is a characteristic mark of heterochromatic regions and telomeres. We found by transmission electron microscopy that EhTRF-like III was located in regions of more condensed chromatin. Finally, EMSA assays showed that EhTRF-like III forms specific DNA-protein complexes with telomeric related sequences. Our data suggested that EhTRF-like proteins play a role in the maintenance of the chromosome ends in this parasite.


Subject(s)
Entamoeba histolytica/metabolism , Protozoan Proteins/metabolism , Telomere-Binding Proteins/metabolism , Telomere/metabolism , Blotting, Western , Cell Nucleus/chemistry , Computational Biology , Cytoplasm/chemistry , Electrophoretic Mobility Shift Assay , Entamoeba histolytica/chemistry , Entamoeba histolytica/genetics , Fluorescent Antibody Technique, Indirect , Gene Expression Profiling , Humans , Microscopy, Electron, Transmission , Protein Binding , Protozoan Proteins/genetics , Sequence Homology, Amino Acid , Telomere-Binding Proteins/genetics
11.
Cell Signal ; 44: 72-81, 2018 04.
Article in English | MEDLINE | ID: mdl-29337043

ABSTRACT

The acrosome reaction is the regulated exocytosis of mammalian sperm's single secretory granule, essential for fertilization. It relies on small GTPases, the cAMP binding protein Epac, and the SNARE complex, among other components. Here, we describe a novel tool to investigate Rab27-related signaling pathways: a hybrid recombinant protein consisting of human Rab27A fused to TAT, a cell penetrating peptide. With this tool, we aimed to unravel the connection between Rab3, Rab27 and Rap1 in sperm exocytosis and to deepen our understanding about how isoprenylation and guanine nucleotides influence the behaviour of Rab27 in exocytosis. Our results show that TAT-Rab27A-GTP-γ-S permeated into live sperm and triggered acrosomal exocytosis per se when geraylgeranylated but inhibited it when not lipid-modified. Likewise, an impermeant version of Rab27A elicited exocytosis in streptolysin O-permeabilized - but not in non-permeabilized - cells when geranylgeranylated and active. When GDP-ß-S substituted for GTP-γ-S, isoprenylated TAT-Rab27A inhibited the acrosome reaction triggered by progesterone and an Epac-selective cAMP analogue, whereas the non-isoprenylated protein did not. Geranylgeranylated TAT-Rab27A-GTP-γ-S promoted the exchange of GDP for GTP on Rab3 and Rap1 detected by far-immunofluorescence with Rab3-GTP and Rap1-GTP binding cassettes. In contrast, TAT-Rab27A lacking isoprenylation or loaded with GDP-ß-S prevented the activation of Rab3 and Rap1 elicited by progesterone. Challenging streptolysin O-permeabilized human sperm with calcium increased the population of sperm with Rap1-GTP, Rab3-GTP and Rab27-GTP in the acrosomal region; pretreatment with anti-Rab27 antibodies prevented the activation of all three. The novel findings reported here include: the description of membrane permeant TAT-Rab27A as a trustworthy tool to unveil the regulation of the human sperm acrosome reaction by Rab27 under physiological conditions; that the activation of endogenous Rab27 is required for that of Rab3 and Rap1; and the connection between Epac and Rab27 and between Rab27 and the configuration of the SNARE complex. Moreover, we present direct evidence that Rab27A's lipid modification, and activation/inactivation status correlate with its stimulatory or inhibitory roles in exocytosis.


Subject(s)
Acrosome Reaction , Exocytosis , Guanine Nucleotides/metabolism , Prenylation , Telomere-Binding Proteins/metabolism , rab27 GTP-Binding Proteins/metabolism , rab3 GTP-Binding Proteins/metabolism , Cell Membrane/metabolism , Cell Membrane Permeability , Cell-Penetrating Peptides/genetics , Cell-Penetrating Peptides/metabolism , Guanine Nucleotide Exchange Factors , Humans , Male , Peptide Fragments/genetics , Peptide Fragments/metabolism , Protein Prenylation , Recombinant Proteins/genetics , SNARE Proteins/metabolism , Shelterin Complex , Signal Transduction , rab27 GTP-Binding Proteins/genetics , tat Gene Products, Human Immunodeficiency Virus/genetics , tat Gene Products, Human Immunodeficiency Virus/metabolism
12.
Biochim Biophys Acta Gen Subj ; 1861(11 Pt A): 2583-2597, 2017 Nov.
Article in English | MEDLINE | ID: mdl-28844976

ABSTRACT

BACKGROUND: Leishmania spp. telomeres are composed of 5'-TTAGGG-3' repeats associated with proteins. We have previously identified LaRbp38 and LaRPA-1 as proteins that bind the G-rich telomeric strand. At that time, we had also partially characterized a protein: DNA complex, named LaGT1, but we could not identify its protein component. METHODS AND RESULTS: Using protein-DNA interaction and competition assays, we confirmed that LaGT1 is highly specific to the G-rich telomeric single-stranded DNA. Three protein bands, with LaGT1 activity, were isolated from affinity-purified protein extracts in-gel digested, and sequenced de novo using mass spectrometry analysis. In silico analysis of the digested peptide identified them as a putative calmodulin with sequences identical to the T. cruzi calmodulin. In the Leishmania genome, the calmodulin ortholog is present in three identical copies. We cloned and sequenced one of the gene copies, named it LCalA, and obtained the recombinant protein. Multiple sequence alignment and molecular modeling showed that LCalA shares homology to most eukaryotes calmodulin. In addition, we demonstrated that LCalA is nuclear, partially co-localizes with telomeres and binds in vivo the G-rich telomeric strand. Recombinant LCalA can bind specifically and with relative affinity to the G-rich telomeric single-strand and to a 3'G-overhang, and DNA binding is calcium dependent. CONCLUSIONS: We have described a novel candidate component of Leishmania telomeres, LCalA, a nuclear calmodulin that binds the G-rich telomeric strand with high specificity and relative affinity, in a calcium-dependent manner. GENERAL SIGNIFICANCE: LCalA is the first reported calmodulin that binds in vivo telomeric DNA.


Subject(s)
Calmodulin/genetics , Leishmania/genetics , Leishmaniasis/genetics , Telomere-Binding Proteins/chemistry , Amino Acid Sequence/genetics , Calmodulin/chemistry , DNA, Single-Stranded/chemistry , DNA, Single-Stranded/genetics , Humans , Leishmania/pathogenicity , Leishmaniasis/parasitology , Protein Binding , Telomere , Telomere-Binding Proteins/genetics
13.
Adv Exp Med Biol ; 949: 205-226, 2016.
Article in English | MEDLINE | ID: mdl-27714691

ABSTRACT

As we age, a large number of physiological and molecular changes affect the normal functioning of cells, tissues, and the organism as a whole. One of the main changes is the establishment of a state of systemic inflammatory activation, which has been termed "inflamm-aging"; a mild chronic inflammation of the aging organism that reduces the ability to generate an efficient response against stressor stimuli. As any other system, the nervous system undergoes these aging-related changes; the neuroinflammatory state depends mainly on the dysregulated activation of microglia, the innate immune cells of the central nervous system (CNS) and the principal producers of reactive oxygen species. As the brain ages, microglia acquire a phenotype that is increasingly inflammatory and cytotoxic, generating a hostile environment for neurons. There is mounting evidence that this process facilitates development of neurodegenerative diseases, for which the greatest risk factor is age. In this chapter, we will review key aging-associated changes occurring in the central nervous system, focusing primarily on the changes that occur in aging microglia, the inflammatory and oxidative stressful environment they establish, and their impaired regulation. In addition, we will discuss the effects of aged microglia on neuronal function and their participation in the development of neurodegenerative pathologies such as Parkinson's and Alzheimer's diseases.


Subject(s)
Aging/metabolism , Alzheimer Disease/metabolism , Central Nervous System/metabolism , Microglia/metabolism , Neurons/metabolism , Parkinson Disease/metabolism , Aged , Aged, 80 and over , Aging/genetics , Aging/pathology , Alzheimer Disease/genetics , Alzheimer Disease/pathology , Central Nervous System/pathology , Cytokines/biosynthesis , DNA Methylation , Histones/genetics , Histones/metabolism , Humans , I-kappa B Kinase/genetics , I-kappa B Kinase/metabolism , Inflammation , Microglia/pathology , Neurons/pathology , Oxidative Stress , Parkinson Disease/genetics , Parkinson Disease/pathology , Reactive Oxygen Species/metabolism , Shelterin Complex , Telomere-Binding Proteins/genetics , Telomere-Binding Proteins/metabolism
14.
Sci Rep ; 6: 29003, 2016 06 30.
Article in English | MEDLINE | ID: mdl-27357373

ABSTRACT

Changes in vascular permeability occur during inflammation and the actin cytoskeleton plays a crucial role in regulating endothelial cell contacts and permeability. We demonstrated recently that the actin-binding protein cortactin regulates vascular permeability via Rap1. However, it is unknown if the actin cytoskeleton contributes to increased vascular permeability without cortactin. As we consistently observed more actin fibres in cortactin-depleted endothelial cells, we hypothesised that cortactin depletion results in increased stress fibre contractility and endothelial barrier destabilisation. Analysing the contractile machinery, we found increased ROCK1 protein levels in cortactin-depleted endothelium. Concomitantly, myosin light chain phosphorylation was increased while cofilin, mDia and ERM were unaffected. Secretion of the barrier-stabilising hormone adrenomedullin, which activates Rap1 and counteracts actomyosin contractility, was reduced in plasma from cortactin-deficient mice and in supernatants of cortactin-depleted endothelium. Importantly, adrenomedullin administration and ROCK1 inhibition reduced actomyosin contractility and rescued the effect on permeability provoked by cortactin deficiency in vitro and in vivo. Our data suggest a new role for cortactin in controlling actomyosin contractility with consequences for endothelial barrier integrity.


Subject(s)
Adrenomedullin/metabolism , Capillary Permeability/physiology , Cortactin/deficiency , Endothelial Cells/physiology , Actomyosin/physiology , Animals , Contractile Proteins/biosynthesis , Contractile Proteins/genetics , Cortactin/antagonists & inhibitors , Cortactin/genetics , Cortactin/physiology , Human Umbilical Vein Endothelial Cells , Humans , Lung/cytology , Male , Mice , RNA Interference , RNA, Small Interfering/genetics , Shelterin Complex , Telomere-Binding Proteins/metabolism , rap1 GTP-Binding Proteins/metabolism , rho-Associated Kinases/antagonists & inhibitors , rho-Associated Kinases/physiology
15.
Genet Mol Res ; 14(3): 9269-76, 2015 Aug 10.
Article in English | MEDLINE | ID: mdl-26345860

ABSTRACT

The objective of this study was to find the key regulatory molecules in the cell senescence process through observing the expression of telomere-associated factor during the normal cell replicative senescence process. Based on the established cell replicative senescence model, reverse transcription-polymerase chain reaction and western blot analyses were used to detect telomere-associated factor expression at the mRNA and protein levels, including that of human telomere binding protein 1, tankyrase 1, telomerase RNA, telomere protection protein 1 (POT1), and p53 during the process of human embryonic lung fibroblast replicative senescence. The results showed that transcription of human telomere binding protein 1 did not change with cell senescence, whereas the protein expression of human telomere binding protein 1 increased gradually and then decreased rapidly; there was no change in the mRNA and protein expression of POT1; with the replicative senescence of human embryonic lung fibroblasts, expression of POT1 decreased gradually; TRF1 showed an increasing trend with cell senescence; and p53 protein expression did not change. Together, the results from this study suggest that human telomere binding protein 1, POT1, and TRF1 played important roles in cell senescence.


Subject(s)
Cellular Senescence/genetics , Fibroblasts/metabolism , Gene Expression , Telomere-Binding Proteins/genetics , Cell Line , Humans , RNA/genetics , Shelterin Complex , Tankyrases/genetics , Tankyrases/metabolism , Telomerase/genetics , Telomere-Binding Proteins/metabolism , Telomeric Repeat Binding Protein 1/genetics , Telomeric Repeat Binding Protein 1/metabolism , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism
16.
PLoS One ; 10(4): e0123531, 2015.
Article in English | MEDLINE | ID: mdl-25856570

ABSTRACT

RAP1 (RAS proximate 1), a small GTP-binding protein of the RAS superfamily, is a putative oncogene that is highly expressed in several malignant cell lines and types of cancers, including some types of squamous cell carcinoma. However, the participation of RAP1 in cervical carcinogenesis is unknown. We conducted a cross-sectional study of paraffin-embedded cervical biopsies to determine the association of RAP1 with cervical intraepithelial neoplasia (CIN). Standard and quantitative immunohistochemistry assessment of RAP1 expression in fixed tissue was performed on 183 paraffin-embedded cervical biopsies that were classified as normal or non-dysplastic mucosa (NDM) (n = 33); CIN grade 1 (n = 84) and CIN grade 2/3 (n = 66). A gradual increase in RAP1 expression in NDM < CIN 1 < CIN 2/3 (p<0.001) specimens was observed and was in agreement with the histopathologic diagnosis. A progressive increase in the RAP1 expression levels increased the risk of CIN 1 [odds ratio (OR) = 3.50; 95% confidence interval (CI) 1.30-10.64] 3.5 fold and the risk of CIN 2/3 (OR = 19.86, 95% CI 6.40-70.79) nearly 20 fold when compared to NDM. In addition, stereotype ordinal regression analysis showed that this progressive increase in RAP1 expression more strongly impacted CIN 2/3 than CIN 1. Our findings suggest that RAP1 may be a useful biomarker for the diagnosis of CIN.


Subject(s)
Biomarkers, Tumor/biosynthesis , Carcinoma, Squamous Cell/genetics , Telomere-Binding Proteins/biosynthesis , Uterine Cervical Dysplasia/genetics , Adolescent , Adult , Aged , Biomarkers, Tumor/genetics , Carcinogenesis/genetics , Carcinoma, Squamous Cell/diagnosis , Carcinoma, Squamous Cell/pathology , Female , Gene Expression Regulation, Neoplastic , Humans , Middle Aged , Neoplasm Staging , Risk Factors , Shelterin Complex , Telomere-Binding Proteins/genetics , Uterine Cervical Dysplasia/diagnosis , Uterine Cervical Dysplasia/pathology
17.
Cad. saúde pública ; Cad. Saúde Pública (Online);31(3): 620-632, 03/2015. tab
Article in Portuguese | LILACS | ID: lil-744835

ABSTRACT

O estudo descreve os pontos de venda de alimentos e sua associação com sobrepeso/obesidade em escolares de Florianópolis, Santa Catarina, Brasil. Desenho transversal com amostra probabilística de 2.506 escolares de escolas públicas (n = 19) e privadas (n = 11). O sobrepeso/obesidade foi classificado pela referência da Organização Mundial da Saúde de 2007. Foram realizadas análises brutas e ajustadas por meio de regressão de Poisson. A prevalência de sobrepeso/obesidade foi de 34,2%. Na rede pública, foram verificados 19,6% de sobrepeso e 13,5% de obesidade. Na rede privada, observaram-se 22,4% de sobrepeso e 11,1% de obesidade. Na rede pública, foi encontrada associação entre sobrepeso/obesidade e utilização da padaria (p = 0,004). Na rede privada, observou-se que os escolares de famílias que utilizaram o supermercado apresentaram 26% menos de sobrepeso/obesidade do que os escolares que não utilizam esses pontos de venda de alimentos (p = 0,003). Os dados encontrados evidenciam a existência de associação entre a utilização de alguns tipos de pontos de venda de alimentos (supermercado e padaria) e a prevalência de sobrepeso/obesidade na população escolar.


The study analyzes retail food outlets and their association with overweight/obesity in schoolchildren from Florianópolis, Santa Catarina State, Brazil. The study used a cross-sectional design with a random sample of 2,506 schoolchildren from public (n = 19) and private schools (n = 11). Overweight and obesity were classified according to World Health Organization guidelines for 2007, and crude and adjusted analyses were performed using Poisson regression. Prevalence of overweight/obesity was 34.2%. In public schools, 19.6% of the children were overweight and 13.5% were obese, as compared to 22.4% and 11.1% in private schools. An association was found in the public school system between overweight/obesity and the use of bakeries for food purchases (p = 0.004). In the private school system, children of families that bought groceries at the supermarket showed 26% less overweight/obesity compared to those who did not (p = 0.003). The data show an association between some types of food outlets (supermarkets and bakeries) and prevalence of overweight/obesity in the school-age population.


El estudio describe los puntos de venta de alimentos y su asociación con el sobrepeso/obesidad en escolares de Florianópolis, Santa Catarina, Brasil. Se trata de un estudio transversal con una muestra aleatoria de 2.506 escolares de las escuelas públicas (n = 19) y privadas (n = 11). El sobrepeso/obesidad se clasifica, en función de la OMS en 2007, con análisis ajustados y crudos que se realizaron mediante la regresión de Poisson. La prevalencia de sobrepeso/obesidad fue de un 34,2%. En el sistema público el resultado fue de un 19,6% sobrepeso y un 13,5% obesidad. En el privado se observó un 22,4% de sobrepeso y 11,1% obesidad. En el primero se encontró una correlación entre el sobrepeso/obesidad y el consumo de bollería (p = 0,004). En las escuelas privadas se observó que los escolares de familias que habían utilizado el supermercado tenían un 26% menos de sobrepeso/ obesidad que los niños en edad escolar que no utilizaron este punto de venta de alimentos (p = 0,003). En el momento del estudio existe una asociación entre el uso de algunos tipos de punto de venta de alimentos (supermercado y panadería) y la prevalencia de sobrepeso/obesidad en escolares.


Subject(s)
DNA, Fungal/chemistry , HSP90 Heat-Shock Proteins/metabolism , Nucleic Acid Conformation , Saccharomyces cerevisiae , Saccharomyces cerevisiae Proteins/metabolism , Telomere/chemistry , Cell Cycle Proteins/genetics , Cell Cycle Proteins/metabolism , Chromosomal Proteins, Non-Histone/genetics , Chromosomal Proteins, Non-Histone/metabolism , DNA, Fungal/metabolism , Enzyme Activation , HSP90 Heat-Shock Proteins/genetics , Saccharomyces cerevisiae Proteins/genetics , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism , Telomerase/metabolism , Telomere-Binding Proteins/genetics , Telomere-Binding Proteins/metabolism , Telomere/metabolism
18.
Sci Rep ; 5: 7869, 2015 Jan 19.
Article in English | MEDLINE | ID: mdl-25598199

ABSTRACT

We tested the hypothesis that leukocyte telomere length (LTL) is associated with birth weight in both extremes of abnormal fetal growth: small (SGA) and large for gestational age newborns (LGA). Clinical and laboratory variables of the mothers and the neonates were explored; 45 newborns with appropriate weight for gestational age (AGA), 12 SGA and 12 LGA were included. Whether the differences might be explained by variation in OBFC1 (rs9419958) and CTC1 (rs3027234) genes associated with LTL was determined. A significant association between birth weight and LTL was observed; LTL was significantly shorter in LGA newborns (1.01 ± 0.12) compared with SGA (1.73 ± 0.19) p < 0.005, mean ± SE. Maternal (Spearman R = -0.6, p = 0.03) and neonatal LTL (R = -0.25, p = 0.03) were significantly and inversely correlated with maternal history of arterial hypertension in previous gestations. Neonatal LTL was not significantly associated with either rs9419950 or rs3027234, suggesting that the association between neonatal LTL and birth weight is not influenced by genetic variation in genes that modify the interindividual LTL. In conclusion, telomere biology seems to be modulated by abnormal fetal growth; modifications in telomere length might be programmed by an adverse environment in utero.


Subject(s)
Fetal Development/genetics , Hypertension/genetics , Telomere Homeostasis/genetics , Telomere-Binding Proteins/genetics , Adult , Birth Weight/genetics , Birth Weight/radiation effects , Female , Fetal Development/physiology , Genetic Association Studies , Humans , Hypertension/physiopathology , Infant, Newborn , Leukocytes/pathology , Pregnancy , Telomere/genetics
19.
Arterioscler Thromb Vasc Biol ; 34(12): 2644-50, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25278289

ABSTRACT

OBJECTIVE: Black individuals are at an increased risk of myocardial infarction and stroke, 2 vascular diseases with strong thrombotic components. Platelet activation is a key step in platelet clot formation leading to myocardial infarction and stroke, and recent work supports a racial difference in platelet aggregation through the thrombin protease-activated receptors (PARs). The underlying mechanism for this racial difference, however, has not been established. Determining where in the signaling cascade these racial differences emerge will aid in understanding why individuals of differing racial ancestry may possess an inherent difference in their responsiveness to antiplatelet therapies. APPROACH AND RESULTS: Washed human platelets from black volunteers were hyperaggregable in response to PAR4-mediated platelet stimulation compared with whites. Interestingly, the racial difference in PAR4-mediated platelet aggregation persisted in platelets treated ex vivo with aspirin and 2MeSAMP (2-methylthioadenosine 5'-monophosphate triethylammonium salt hydrate), suggesting that the racial difference is independent of secondary feedback. Furthermore, stimulation of platelets from black donors with PAR4-activating peptide showed a potentiated level of activation through the Gq pathway compared with platelets from white donors. Differences in signaling included increased Ca(2+) mobilization, Rap1 (Ras-related protein 1) activation, and integrin αIIbß3 activation with no observed difference in platelet protein expression between the groups tested. CONCLUSIONS: Our study is the first to demonstrate that the Gq pathway is differentially regulated by race after PAR4 stimulation in human platelets. Furthermore, the racial difference in PAR4-mediated platelet aggregation persisted in the presence of cyclooxygenase and P2Y12 receptor dual inhibition, suggesting that current antiplatelet therapy may provide less protection to blacks than whites.


Subject(s)
Black People , GTP-Binding Protein alpha Subunits, Gq-G11/blood , Platelet Activation/physiology , Receptors, Thrombin/blood , White People , Adult , Calcium Signaling , Cyclooxygenase Inhibitors/pharmacology , Female , Humans , Male , Platelet Activation/drug effects , Platelet Aggregation/physiology , Platelet Glycoprotein GPIIb-IIIa Complex/metabolism , Prostaglandin-Endoperoxide Synthases/blood , Protein Kinase C/blood , Purinergic P2Y Receptor Antagonists/pharmacology , Receptors, Purinergic P2Y12/blood , Shelterin Complex , Signal Transduction , Telomere-Binding Proteins/blood
20.
Blood Cells Mol Dis ; 52(2-3): 134-9, 2014.
Article in English | MEDLINE | ID: mdl-24239198

ABSTRACT

The core complex of telomere-associated proteins, named the shelterin complex, plays a critical role in telomere protection and telomere length (TL) homeostasis. In this study, we have explored changes in the expression of telomere-associated genes POT1, TIN2, RAP1 and TPP1, in patients with monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma (MM). A total of 154 patients: 70 with MGUS and 84 with MM were studied. Real-time quantitative PCR was used to quantify gene expression. TL was evaluated by Terminal Restriction Fragments. Our data showed increased expression of POT1, TPP1, TIN2 and RAP1 in MM with respect to MGUS patients, with significant differences for POT1 gene (p=0.002). In MM, the correlation of gene expression profiles with clinical characteristics highlighted POT1 for its significant association with advanced clinical stages, high calcium and ß2-microglobulin levels (p=0.02) and bone lesions (p=0.009). In multivariate analysis, POT1 expression (p=0.04) was a significant independent prognostic factor for overall survival as well as the staging system (ISS) (p<0.02). Our findings suggest for the first time the participation of POT1 in the transformation process from MGUS to MM, and provide evidence of this gene as a useful prognostic factor in MM as well as a possible molecular target to design new therapeutic strategies.


Subject(s)
Gene Expression Profiling , Monoclonal Gammopathy of Undetermined Significance/genetics , Multiple Myeloma/genetics , Telomere-Binding Proteins/genetics , Aged , Aged, 80 and over , DNA Methylation , Follow-Up Studies , Galectin 1/genetics , Humans , Middle Aged , Monoclonal Gammopathy of Undetermined Significance/drug therapy , Monoclonal Gammopathy of Undetermined Significance/mortality , Monoclonal Gammopathy of Undetermined Significance/pathology , Multiple Myeloma/drug therapy , Multiple Myeloma/mortality , Multiple Myeloma/pathology , Prognosis , Promoter Regions, Genetic , Shelterin Complex , Telomerase/genetics
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