Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P04637 (p53)
 77,613 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

P53 protein expression and stabilization in cell strains derived from patients suffering from progeria and ataxia-telangiectasia following gamma-irradiation have been described. A similar pattern of P53-status in healthy donor and progeria patient cells was shown using immunofluorescent cell staining. In ataxia-telangiectasia cells (strain AT2SP) the P53 protein was not detected by the same method. These data well compare with literary evidence on a disturbed P53-status at ataxia-telangiectasia.
 ...
PMID:[P53-status of cells from patients with progeria and ataxia-telangiectasia exposed to ionizing irradiation]. 1056 91

It has been shown that enhanced levels of p53 activity contribute to reduced cancer susceptibility in mice, however longevity is compromised due to the onset of an early-ageing phenotype. The effects of enhanced levels of p53 in these in mice could therefore have implications for human premature ageing disorders. We examined the DNA damage response of p53 and its target p21(WAF1) to UV and ionising radiation in fibroblasts from patients with the premature ageing disorder Hutchinson-Gilford Progeria (HGP). We report a normal p53 response to these DNA damaging agents suggesting that, in this particular human disorder, the premature ageing phenotype does not arise from an enhanced p53 response.
 ...
PMID:p53 and a human premature ageing disorder. 1273

Accelerated aging or progeria has been a puzzling disease for many years. The recent findings involving the lamin A/FACE-1 (substrate/protease) system in the etiology of Hutchinson-Gilford progeria syndrome and related pathologies have shed some light on the mechanisms underlying the development of these devastating conditions. Thus, genetic defects in the nuclear envelope protein prelamin A or in the FACE-1 metalloprotease (also called Zmspte24) involved in prelamin A proteolytic maturation, cause the accumulation of an abnormal form of this protein and the subsequent disruption of nuclear envelope integrity. Recently, we and others have observed how this disruption leads to alterations in chromatin organization, genomic instability, transcriptional changes, and activation of a p53-linked signaling pathway. By using genetic manipulation approaches in mouse, we have shown that lowering prelamin A levels results in a total recovery of Zmpste24-deficient mice from the accelerated aging process. Moreover, p53 nullizygosity allows a modest but significant improvement in the premature aging phenotype, and contributes to delaying the onset of the progeroid condition. On the basis of these results, we propose different potential therapeutic approaches that could be tested in Zmpste24-deficient mice. These strategies, some of which are based on existing drugs, might contribute to the development of effective treatments for these dramatic pathologies.
 ...
PMID:From immature lamin to premature aging: molecular pathways and therapeutic opportunities. 1625 83

Hyperactivation of mammalian p53 has been shown to result in segmental progeria and decreased survivorship. Repression of the p53 homolog in Drosophila melanogaster has also been shown to increase survival. We show that RNA interference (RNAi) or genetic knockout of the Caenorhabditis elegans p53 ortholog, cep-1, leads to increased life span, which is dependent upon functional daf-16. Furthermore, one other DNA damage-responsive C. elegans mutant, hus-1(op241), exhibits a life-span increase. The cep-1(gk138) knockout mutant does not show increased resistance to heat, oxidative, or ultraviolet stress; nor to bacterial pathogenicity. cep-1 RNAi does not extend the life span of a sir-2.1(geIn3) overexpressing strain. cep-1 RNAi does not alter dauer formation propensity or nuclear-localization of DAF-16::GFP, even under heat stress; nor does it change nuclear-persistence and/or retention of DAF-16::GFP. This study clarifies the inverse relationship between cep-1 expression and C. elegans life span, and, by extrapolation, that between p53 expression and mammalian life span.
 ...
PMID:Reduced expression of the Caenorhabditis elegans p53 ortholog cep-1 results in increased longevity. 1789 32

Antioxidants specifically addressed to mitochondria have been studied for their ability to decelerate aging of organisms. For this purpose, a project has been established with participation of several research groups from Belozersky Institute of Physico-Chemical Biology and some other Russian research institutes as well as two groups from the USA and Sweden, with support by the "Mitotechnology" company founded by "RAInKo" company (O. V. Deripaska and Moscow State University). This paper summarizes the first results of the project and estimates its prospects. Within the framework of the project, antioxidants of a new type (SkQ) were synthesized comprising plastoquinone (an antioxidant moiety), a penetrating cation, and decane or pentane linker. Using planar bilayer phospholipid membranes, we selected SkQ derivatives with the highest penetrating ability, namely plastoquinonyl-decyl-triphenylphosphonium (SkQ1), plastoquinonyl-decyl-rhodamine 19 (SkQR1), and methylplastoquinonyl-decyl-triphenylphosphonium (SkQ3). Anti- and prooxidant properties of these substances and also of ubiquinone and ubiquinonyl-decyl-triphenylphosphonium (MitoQ) were tested on isolated mitochondria. Micromolar concentrations of cationic quinones are found to be very strong prooxidants, but in lower (sub-micromolar) concentrations they display antioxidant activity. The antioxidant activity decreases in the series SkQ1=SkQR1>SkQ3>MitoQ, so the window between the anti- and prooxidant effects is smallest for MitoQ. SkQ1 is rapidly reduced by complexes I and II of the mitochondrial respiratory chain, i.e. it is a rechargeable antioxidant. Extremely low concentrations of SkQ1 and SkQR1 completely arrest the H2O2-induced apoptosis in human fibroblasts and HeLa cells (for SkQ1 C1/2=1.10(-9) M). Higher concentrations of SkQ are required to block necrosis initiated by reactive oxygen species (ROS). In mice, SkQ1 decelerates the development of three types of accelerated aging (progeria) and also of normal aging, and this effect is especially demonstrative at early stages of aging. The same pattern is shown in invertebrates (drosophila and daphnia). In mammals, the effect of SkQs on aging is accompanied by inhibition of development of such age-related diseases as osteoporosis, involution of thymus, cataract, retinopathy, etc. SkQ1 manifests a strong therapeutic action on some already developed retinopathies, in particular, congenital retinal dysplasia. With drops containing 250 nM SkQ1, vision is recovered in 50 of 66 animals who became blind because of retinopathy. SkQ1-containing drops instilled in the early stage of the disease prevent the loss of sight in rabbits with experimental uveitis and restore vision to animals that had already become blind. A favorable effect is also achieved in experimental glaucoma in rabbits. Moreover, the pretreatment of rats with 0.2 nmol SkQ1 per kg body weight significantly decreases the H2O2-induced arrhythmia of the isolated heart. SkQ1 strongly reduces the damaged area in myocardial infarction or stroke and prevents the death of animals from kidney infarction. In p53-/- mice, SkQ1 decreases the ROS level in the spleen cells and inhibits appearance of lymphomas which are the main cause of death of such animals. Thus, it seems reasonable to perform clinical testing of SkQ preparations as promising drugs for treatment of age-related and some other severe diseases of human and animals.
 ...
PMID:A biochemical approach to the problem of aging: "megaproject" on membrane-penetrating ions. The first results and prospects. 1820 23

Mandibuloacral dysplasia type A (MADA; OMIM # 248370) is a premature ageing disease caused by the homozygous R527H mutation in the LMNA gene. At the cellular level, MADA is characterized by unprocessed prelamin A accumulation, nuclear architecture alterations, chromatin defects and increased incidence of apoptosis. In some progeroid laminopathies (e.g., HGPS) it has been demonstrated that such biochemical and morphological alterations are strongly linked with genomic instability. To test this also in MADA fibroblasts, their response to the ionising radiation-induced damage was analysed. We observed that their ability to repair the damage was significantly impaired, as demonstrated by the increased chromosome damage and the higher percentage of residual gamma-H2AX foci, corresponding to unrepaired DNA-damage sites. Moreover, MADA fibroblasts showed a markedly reduced phosphorylation of p53 at Ser15(S15) and a lower induction of p53 and CDKN1A proteins after irradiation, compared to the control cell line. Upon irradiation, we also detected differences in the expression of some p53 downstream target genes. In addition, MADA cells showed partial defects in the checkpoint response, particularly in G(1)/S transition. Our results indicate that accumulation of the lamin A precursor protein determines a defect in DNA damage response after X-ray exposure, supporting a crucial role of lamin A in regulating DNA repair process and cell cycle control.
 ...
PMID:The R527H mutation in LMNA gene causes an increased sensitivity to ionizing radiation. 1860 66

Senescence of cultured cells involves activation of the p19(Arf)-p53 and the p16(Ink4a)-Rb tumor suppressor pathways. This, together with the observation that p19(Arf) and p16(Ink4a) expression increases with age in many tissues of humans and rodents, led to the speculation that these pathways drive in vivo senescence and natural aging. However, it has been difficult to test this hypothesis using a mammalian model system because inactivation of either of these pathways results in early death from tumors. One approach to bypass this problem would be to inactivate these pathways in a murine segmental progeria model such as mice that express low amounts of the mitotic checkpoint protein BubR1 (BubR1 hypomorphic mice). These mice have a five-fold reduced lifespan and develop a variety of early-aging associated phenotypes including cachetic dwarfism, skeletal muscle degeneration, cataracts, arterial stiffening, (subcutaneous) fat loss, reduced stress tolerance and impaired wound healing. Importantly, BubR1 hypomorphism elevates both p16(Ink4a) and p19(Arf) expression in skeletal muscle and fat. Inactivation of p16(Ink4a) in BubR1 mutant mice delays both cellular senescence and aging specifically in these tissues. Surprisingly, however, inactivation of p19(Arf) has the opposite effect; it exacerbates in vivo senescence and aging in skeletal muscle and fat. These mouse studies suggest that p16(Ink4a) is indeed an effector of aging and in vivo senescence, but p19(Arf) an attenuator. Thus, the role of the p19(Arf)-p53 pathway in aging and in vivo senescence seems far more complex than previously anticipated.
 ...
PMID:The yin and yang of the Cdkn2a locus in senescence and aging. 1876 41

Hutchinson-Gilford progeria syndrome (HGPS) is a rare, debilitating disease with early mortality and rapid onset of aging-associated pathologies. It is linked to mutations in LMNA, which encodes A-type nuclear lamins. The most frequent HGPS-associated LMNA mutation results in a protein, termed progerin, with an internal 50 amino acid deletion and, unlike normal A-type lamins, stable farnesylation. The cellular consequences of progerin expression underlying the HGPS phenotype remain poorly understood. Here, we stably expressed lamin A mutants, including progerin, in otherwise identical primary human fibroblasts to compare the effects of different mutants on nuclear morphology and cell proliferation. We find that expression of progerin leads to inhibition of proliferation in a high percentage of cells and slightly premature senescence in the population. Expression of a stably farnesylated mutant of lamin A phenocopied the immediate proliferative defects but did not result in premature senescence. Either p53 inhibition or, more surprisingly, expression of the catalytic subunit of telomerase (hTERT) suppressed the early proliferative defects associated with progerin expression. These findings lead us to propose that progerin may interfere with telomere structure or metabolism in a manner suppressible by increased telomerase levels and possibly link mechanisms leading to progeroid phenotypes to those of cell immortalization.
 ...
PMID:Suppression of proliferative defects associated with processing-defective lamin A mutants by hTERT or inactivation of p53. 1884 43

The molecular mechanisms involved in human aging are complicated. Two progeria syndromes, Werner's syndrome (WS) and Hutchinson-Gilford progeria syndrome (HGPS), characterized by clinical features mimicking physiological aging at an early age, provide insights into the mechanisms of natural aging. Based on recent findings on WS and HGPS, we suggest a model of human aging. Human aging can be triggered by two main mechanisms, telomere shortening and DNA damage. In telomere-dependent aging, telomere shortening and dysfunction may lead to DNA damage responses which induce cellular senescence. In DNA damage-initiated aging, DNA damage accumulates, along with DNA repair deficiencies, resulting in genomic instability and accelerated cellular senescence. In addition, aging due to both mechanisms (DNA damage and telomere shortening) is strongly dependent on p53 status. These two mechanisms can also act cooperatively to increase the overall level ofgenomic instability, triggering the onset of human aging phenotypes.
 ...
PMID:Model of human aging: recent findings on Werner's and Hutchinson-Gilford progeria syndromes. 1898 14

Ageing research benefits from the study of accelerated ageing syndromes such as Hutchinson-Gilford progeria syndrome (HGPS), characterized by the early appearance of symptoms normally associated with advanced age. Most HGPS cases are caused by a mutation in the gene LMNA, which leads to the synthesis of a truncated precursor of lamin A known as progerin that lacks the target sequence for the metallopotease FACE-1/ZMPSTE24 and remains constitutively farnesylated. The use of Face-1/Zmpste24-deficient mice allowed us to demonstrate that accumulation of farnesylated prelamin A causes severe abnormalities of the nuclear envelope, hyper-activation of p53 signalling, cellular senescence, stem cell dysfunction and the development of a progeroid phenotype. The reduction of prenylated prelamin A levels in genetically modified mice leads to a complete reversal of the progeroid phenotype, suggesting that inhibition of protein farnesylation could represent a therapeutic option for the treatment of progeria. However, we found that both prelamin A and its truncated form progerin can undergo either farnesylation or geranylgeranylation, revealing the need of targeting both activities for an efficient treatment of HGPS. Using Face-1/Zmpste24-deficient mice as model, we found that a combination of statins and aminobisphosphonates inhibits both types of modifications of prelamin A and progerin, improves the ageing-like symptoms of these mice and extends substantially their longevity, opening a new therapeutic possibility for human progeroid syndromes associated with nuclear-envelope defects. We discuss here the use of this and other animal models to investigate the molecular mechanisms underlying accelerated ageing and to test strategies for its treatment.
 ...
PMID:Accelerated ageing: from mechanism to therapy through animal models. 1901 45


1 2 3 4 Next >>