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The role of telomere biology in bone marrow failure and other disorders.

ABSTRACT: Telomeres, consisting of nucleotide repeats and a protein complex at chromosome ends, are essential in maintaining chromosomal integrity. Dyskeratosis congenita (DC) is the inherited bone marrow failure syndrome (IBMFS) that epitomizes the effects of abnormal telomere biology. Patients with DC have extremely short telomere lengths (<1st percentile) and many have mutations in telomere biology genes. Interpretation of telomere length in other IBMFSs is less straightforward. Abnormal telomere shortening has been reported in patients with apparently acquired hematologic disorders, including aplastic anemia, myeolodysplasia, paroxysmal nocturnal hemoglobinuria, and leukemia. In these disorders, the shortest-lived cells have the shortest telomeres, suggestive of increased hematopoietic stress. Telomeres are also markers of replicative and/or oxidative stress in other complex disease pathways, such as inflammation, stress, and carcinogenesis. The spectrum of related disorders caused by mutations in telomere biology genes extends beyond classical DC to include marrow failure that does not respond to immunosuppression, idiopathic pulmonary fibrosis, and possibly other syndromes. We suggest that such patients be categorized as having an inherited disorder of telomere biology. Longitudinal studies of patients with very short telomeres but without classical DC are necessary to further understand the long-term sequelae, such as malignancy, osteonecrosis/osteoporosis, and pulmonary and liver disease.

SUBMITTER: Savage SA

PROVIDER: S-EPMC2278290 | biostudies-literature | 2008 Jan-Feb

REPOSITORIES: biostudies-literature

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The role of telomere biology in bone marrow failure and other disorders.

Savage Sharon A SA Alter Blanche P BP

Mechanisms of ageing and development 20071119 1-2

Telomeres, consisting of nucleotide repeats and a protein complex at chromosome ends, are essential in maintaining chromosomal integrity. Dyskeratosis congenita (DC) is the inherited bone marrow failure syndrome (IBMFS) that epitomizes the effects of abnormal telomere biology. Patients with DC have extremely short telomere lengths (<1st percentile) and many have mutations in telomere biology genes. Interpretation of telomere length in other IBMFSs is less straightforward. Abnormal telomere short ...[more]

PMID: 18160098

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Project description:Dyskeratosis congenita (DC) is an inherited multi-system disorder, characterized by oral leukoplakia, nail dystrophy, and abnormal skin pigmentation, as well as high rates of bone marrow failure, solid tumors, and other medical problems such as osteopenia. DC and telomere biology disorders (collectively referred to as TBD here) are caused by germline mutations in telomere biology genes leading to very short telomeres and limited proliferative potential of hematopoietic stem cells. We found that skeletal stem cells (SSCs) within the bone marrow stromal cell population (BMSCs, also known as bone marrow-derived mesenchymal stem cells), may contribute to the hematological phenotype. TBD-BMSCs exhibited reduced clonogenicity, reduced telomerase activity, spontaneous differentiation into adipocytes and fibrotic cells, and increased senescence in vitro. Upon in vivo transplantation into mice, TBD-BMSCs failed to form bone or support hematopoiesis, unlike normal BMSCs. TERC reduction (a TBD-associated gene) in normal BMSCs by siTERC-RNA recapitulated the TBD-BMSC phenotype by reducing proliferation and secondary colony forming efficiency, and by accelerating senescence in vitro. Microarray profiles of control and siTERC-BMSCs showed decreased hematopoietic factors at the mRNA level, and decreased secretion of factors at the protein level. These findings are consistent with defects in SSCs/BMSCs contributing to bone marrow failure in TBD. RNA (5 mg) isolated from N-BMSCs, siNC-BMSCs and siTERC-BMSCs 72hrs after transfection using an RNeasy Mini kit (Qiagen), was reverse transcribed and hybridized to an Affymetrix GeneChip Human Genome U133 Plus 2.0 array (LMT, NCI-Frederick). Three independent replicates for each experimental condition were carried out to control for intra-sample variation. Genes that were under/over-represented by >2-fold were analyzed using GeneSpring software. Signal intensity values were normalized using RMA (Robust Multi-array Analysis) summarization and baseline transformation to median of all samples was performed. Entities were filtered based on their signal intensity values. Hierarchical clustering was performed on filtered signal intensity (>20.0), non-averaged, fold change >2. A fold change analysis (>10-fold) was performed to generate a list of top genes under/over represented between the groups.

Dataset Information

The role of telomere biology in bone marrow failure and other disorders.

Publications

The role of telomere biology in bone marrow failure and other disorders.

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