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1.
Patient Educ Couns ; 103(1): 127-135, 2020 01.
Artículo en Inglés | MEDLINE | ID: mdl-31521424

RESUMEN

OBJECTIVE: Growing use of clinical exome sequencing (CES) has led to an increased burden of genomic education. Self-guided educational tools can minimize the educational burden for genetic counselors (GCs). The effectiveness of these tools must be evaluated. METHODS: Parents of patients offered CES were randomized to watch educational videos before their visit or to receive routine care. Parents and GCs were surveyed about their experiences following the sessions. The responses of the video (n = 102) and no-video (n = 105) groups were compared. RESULTS: GCs reported no significant differences between parents in the video and no-video groups on genetics knowledge or CES knowledge. In contrast, parents' scores on genetics knowledge questions were lower in the video than no-video group (p = 0.007). Most parents reported the videos were informative, and the groups did not differ in satisfaction with GCs or decisions to have CES. CONCLUSION: GCs and parents perceived the videos to be beneficial. However, lower scores on genetics knowledge questions highlight the need for careful development of educational tools. PRACTICE IMPLICATIONS: Educational tools should be developed and assessed for effectiveness with the input of all stakeholders before widespread implementation. Better measures of the effectiveness of these educational tools are needed.


Asunto(s)
Consejeros , Asesoramiento Genético , Exoma , Humanos , Padres , Educación del Paciente como Asunto
2.
Aging Cell ; 18(5): e12998, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31309734

RESUMEN

Caenorhabditis elegans is an excellent model for high-throughput experimental approaches but lacks an automated means to pinpoint time of death during survival assays over a short time frame, that is, easy to implement, highly scalable, robust, and versatile. Here, we describe an automated, label-free, high-throughput method using death-associated fluorescence to monitor nematode population survival (dubbed LFASS for label-free automated survival scoring), which we apply to severe stress and infection resistance assays. We demonstrate its use to define correlations between age, longevity, and severe stress resistance, and its applicability to parasitic nematodes. The use of LFASS to assess the effects of aging on susceptibility to severe stress revealed an unexpected increase in stress resistance with advancing age, which was largely autophagy-dependent. Correlation analysis further revealed that while severe thermal stress resistance positively correlates with lifespan, severe oxidative stress resistance does not. This supports the view that temperature-sensitive protein-handling processes more than redox homeostasis underpin aging in C. elegans. That the ages of peak resistance to infection, severe oxidative stress, heat shock, and milder stressors differ markedly suggests that stress resistance and health span do not show a simple correspondence in C. elegans.


Asunto(s)
Envejecimiento/fisiología , Automatización , Caenorhabditis elegans/fisiología , Estrés Fisiológico , Animales , Homeostasis , Oxidación-Reducción , Estrés Oxidativo , Análisis de Supervivencia , Temperatura
3.
Am J Hum Genet ; 105(2): 403-412, 2019 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-31303265

RESUMEN

POU3F3, also referred to as Brain-1, is a well-known transcription factor involved in the development of the central nervous system, but it has not previously been associated with a neurodevelopmental disorder. Here, we report the identification of 19 individuals with heterozygous POU3F3 disruptions, most of which are de novo variants. All individuals had developmental delays and/or intellectual disability and impairments in speech and language skills. Thirteen individuals had characteristic low-set, prominent, and/or cupped ears. Brain abnormalities were observed in seven of eleven MRI reports. POU3F3 is an intronless gene, insensitive to nonsense-mediated decay, and 13 individuals carried protein-truncating variants. All truncating variants that we tested in cellular models led to aberrant subcellular localization of the encoded protein. Luciferase assays demonstrated negative effects of these alleles on transcriptional activation of a reporter with a FOXP2-derived binding motif. In addition to the loss-of-function variants, five individuals had missense variants that clustered at specific positions within the functional domains, and one small in-frame deletion was identified. Two missense variants showed reduced transactivation capacity in our assays, whereas one variant displayed gain-of-function effects, suggesting a distinct pathophysiological mechanism. In bioluminescence resonance energy transfer (BRET) interaction assays, all the truncated POU3F3 versions that we tested had significantly impaired dimerization capacities, whereas all missense variants showed unaffected dimerization with wild-type POU3F3. Taken together, our identification and functional cell-based analyses of pathogenic variants in POU3F3, coupled with a clinical characterization, implicate disruptions of this gene in a characteristic neurodevelopmental disorder.


Asunto(s)
Regulación de la Expresión Génica , Mutación , Trastornos del Neurodesarrollo/etiología , Factores del Dominio POU/genética , Activación Transcripcional , Secuencia de Aminoácidos , Niño , Femenino , Estudios de Asociación Genética , Genotipo , Humanos , Masculino , Trastornos del Neurodesarrollo/patología , Factores del Dominio POU/química , Conformación Proteica , Homología de Secuencia
4.
J Gerontol A Biol Sci Med Sci ; 74(8): 1180-1188, 2019 07 12.
Artículo en Inglés | MEDLINE | ID: mdl-30854561

RESUMEN

During aging, etiologies of senescence cause multiple pathologies, leading to morbidity and death. To understand aging requires identification of these etiologies. For example, Caenorhabditis elegans hermaphrodites consume their own intestinal biomass to support yolk production, which in later life drives intestinal atrophy and ectopic yolk deposition. Yolk proteins (YPs; vitellogenins) exist as three abundant species: YP170, derived from vit-1-vit-5; and YP115 and YP88, derived from vit-6. Here, we show that inhibiting YP170 synthesis leads to a reciprocal increase in YP115/YP88 levels and vice versa, an effect involving posttranscriptional mechanisms. Inhibiting YP170 production alone, despite increasing YP115/YP88 synthesis, reduces intestinal atrophy as much as inhibition of all YP synthesis, which increases life span. By contrast, inhibiting YP115/YP88 production alone accelerates intestinal atrophy and reduces life span, an effect that is dependent on increased YP170 production. Thus, despite copious abundance of both YP170 and YP115/YP88, only YP170 production is coupled to intestinal atrophy and shortened life span. In addition, increasing levels of YP115/YP88 but not of YP170 increases resistance to oxidative stress; thus, longevity resulting from reduced vitellogenin synthesis is not attributable to oxidative stress resistance.


Asunto(s)
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/fisiología , Mucosa Intestinal/metabolismo , Longevidad/fisiología , Vitelogeninas/metabolismo , Animales , Atrofia , Mucosa Intestinal/patología , Estrés Oxidativo
5.
Org Biomol Chem ; 17(3): 664-674, 2019 01 16.
Artículo en Inglés | MEDLINE | ID: mdl-30601550

RESUMEN

Stereoselective fluorination is investigated as a method for modulating the properties of a cyclic RGD-containing tetrapeptide. Three key outcomes of fluorination are assessed: (i) the effect on peptide cyclisation efficiency; (ii) the ability to fine-tune the molecular conformation; and (iii) the effect on the cyclic peptides' biological activity. Fluorination is found to exert pronounced effects against all three criteria.

7.
Curr Biol ; 28(16): 2544-2556.e5, 2018 08 20.
Artículo en Inglés | MEDLINE | ID: mdl-30100339

RESUMEN

Aging (senescence) is characterized by the development of numerous pathologies, some of which limit lifespan. Key to understanding aging is discovery of the mechanisms (etiologies) that cause senescent pathology. In C. elegans, a major senescent pathology of unknown etiology is atrophy of its principal metabolic organ, the intestine. Here we identify a cause of not only this pathology but also of yolky lipid accumulation and redistribution (a form of senescent obesity): autophagy-mediated conversion of intestinal biomass into yolk. Inhibiting intestinal autophagy or vitellogenesis rescues both visceral pathologies and can also extend lifespan. This defines a disease syndrome leading to multimorbidity and contributing to late-life mortality. Activation of gut-to-yolk biomass conversion by insulin/IGF-1 signaling (IIS) promotes reproduction and senescence. This illustrates how major, IIS-promoted senescent pathologies in C. elegans can originate not from damage accumulation but from direct effects of futile, continued action of a wild-type biological program (vitellogenesis).


Asunto(s)
Envejecimiento/fisiología , Autofagia/fisiología , Caenorhabditis elegans/fisiología , Yema de Huevo/metabolismo , Intestinos/fisiología , Vitelogénesis/fisiología , Animales , Transducción de Señal
8.
Gastroenterol Nurs ; 40(5): 350-356, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28957967

RESUMEN

In Australia, nurses performing endoscopic procedures is a recent phenomenon and is uncommon. Challenges include gastroenterologist and patient acceptance of the nurse endoscopist role. This article aims to explore Monash Health's experience with the introduction of a nurse endoscopist. A nurse endoscopist trainee undertook a comprehensive training program under the supervision of a gastroenterologist. All procedural data were collected, organizational policy and procedures were developed, and patients (n = 40) completed a telephone interview postprocedure. The nurse endoscopist trainee completed all training requirements during the 12-month program and was deemed competent for independent practice. The trainee performed 255 colonoscopies, with no complications reported. The organization successfully implemented the expanded scope of practice, established a new model of care for patients, and initiated a governance framework for this advanced practice role. Eighty percent of patients (n = 32) reported that overall, they had a very good experience with the nurse endoscopist trainee. A nurse endoscopist initiative can facilitate the expansion of endoscopy services to meet the growing need for gastroenterological procedures within the community. This pilot program has demonstrated that it is possible to integrate an advanced practice nurse role into an established endoscopy unit.


Asunto(s)
Enfermería de Práctica Avanzada/métodos , Atención a la Salud/organización & administración , Endoscopía Gastrointestinal/enfermería , Rol de la Enfermera , Adulto , Enfermería de Práctica Avanzada/educación , Anciano , Australia , Competencia Clínica , Estudios de Cohortes , Endoscopía Gastrointestinal/métodos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Adulto Joven
9.
Mol Cell Proteomics ; 16(12): 2048-2054, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28954815

RESUMEN

GOLPH3 is the first example of a Golgi resident oncogene protein. It was independently identified in multiple screens; first in proteomic-based screens as a resident protein of the Golgi apparatus, and second as an oncogene product in a screen for genes amplified in cancer. A third screen uncovered the association of GOLPH3 with the Golgi resident phospholipid, phosphatidyl inositol 4 phosphate (PI4P) to maintain the characteristic ribbon structure of the Golgi apparatus favoring vesicular transport of secretory proteins.


Asunto(s)
Aparato de Golgi/química , Proteínas de la Membrana/metabolismo , Neoplasias/metabolismo , Fosfatos de Fosfatidilinositol/metabolismo , Proteómica/métodos , Animales , Muerte Celular , Daño del ADN , Amplificación de Genes , Aparato de Golgi/metabolismo , Humanos , Hígado/metabolismo , Proteínas de la Membrana/química , Modelos Moleculares , Estructura Terciaria de Proteína
10.
Aging Cell ; 16(5): 1191-1194, 2017 10.
Artículo en Inglés | MEDLINE | ID: mdl-28612944

RESUMEN

In C. elegans, the skn-1 gene encodes a transcription factor that resembles mammalian Nrf2 and activates a detoxification response. skn-1 promotes resistance to oxidative stress (Oxr) and also increases lifespan, and it has been suggested that the former causes the latter, consistent with the theory that oxidative damage causes aging. Here, we report that effects of SKN-1 on Oxr and longevity can be dissociated. We also establish that skn-1 expression can be activated by the DAF-16/FoxO transcription factor, another central regulator of growth, metabolism, and aging. Notably, skn-1 is required for Oxr but not increased lifespan resulting from over-expression of DAF-16; concomitantly, DAF-16 over-expression rescues the short lifespan of skn-1 mutants but not their hypersensitivity to oxidative stress. These results suggest that SKN-1 promotes longevity by a mechanism other than protection against oxidative damage.


Asunto(s)
Proteínas de Caenorhabditis elegans/genética , Caenorhabditis elegans/genética , Proteínas de Unión al ADN/genética , Factores de Transcripción Forkhead/genética , Regulación del Desarrollo de la Expresión Génica , Longevidad/genética , Factores de Transcripción/genética , Animales , Caenorhabditis elegans/crecimiento & desarrollo , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/antagonistas & inhibidores , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Unión al ADN/antagonistas & inhibidores , Proteínas de Unión al ADN/metabolismo , Factores de Transcripción Forkhead/metabolismo , Estrés Oxidativo , Interferencia de ARN , Transducción de Señal , Factores de Transcripción/antagonistas & inhibidores , Factores de Transcripción/metabolismo
11.
BMC Pharmacol Toxicol ; 17(1): 54, 2016 11 02.
Artículo en Inglés | MEDLINE | ID: mdl-27802836

RESUMEN

BACKGROUND: All living cells display a rapid molecular response to adverse environmental conditions, and the heat shock protein family reflects one such example. Hence, failing to activate heat shock proteins can impair the cellular response. In the present study, we evaluated whether the loss of different isoforms of heat shock protein (hsp) genes in Caenorhabditis elegans would affect their vulnerability to Manganese (Mn) toxicity. METHODS: We exposed wild type and selected hsp mutant worms to Mn (30 min) and next evaluated further the most susceptible strains. We analyzed survival, protein carbonylation (as a marker of oxidative stress) and Parkinson's disease related gene expression immediately after Mn exposure. Lastly, we observed dopaminergic neurons in wild type worms and in hsp-70 mutants following Mn treatment. Analysis of the data was performed by one-way or two way ANOVA, depending on the case, followed by post-hoc Bonferroni test if the overall p value was less than 0.05. RESULTS: We verified that the loss of hsp-70, hsp-3 and chn-1 increased the vulnerability to Mn, as exposed mutant worms showed lower survival rate and increased protein oxidation. The importance of hsp-70 against Mn toxicity was then corroborated in dopaminergic neurons, where Mn neurotoxicity was aggravated. The lack of hsp-70 also blocked the transcriptional upregulation of pink1, a gene that has been linked to Parkinson's disease. CONCLUSIONS: Taken together, our data suggest that Mn exposure modulates heat shock protein expression, particularly HSP-70, in C. elegans. Furthermore, loss of hsp-70 increases protein oxidation and dopaminergic neuronal degeneration following manganese exposure, which is associated with the inhibition of pink1 increased expression, thus potentially exacerbating the vulnerability to this metal.


Asunto(s)
Proteínas de Caenorhabditis elegans/biosíntesis , Proteínas de Choque Térmico/biosíntesis , Manganeso/toxicidad , Animales , Animales Modificados Genéticamente , Caenorhabditis elegans , Proteínas de Caenorhabditis elegans/antagonistas & inhibidores , Proteínas de Caenorhabditis elegans/genética , Relación Dosis-Respuesta a Droga , Proteínas de Choque Térmico/antagonistas & inhibidores , Proteínas de Choque Térmico/genética , Estrés Oxidativo/efectos de los fármacos , Estrés Oxidativo/fisiología
12.
Open Biol ; 5(8)2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26311421

RESUMEN

Discovered in 1909 by Retzius and described mainly by morphology, the cytoplasmic droplet of sperm (renamed here the Hermes body) is conserved among all mammalian species but largely undefined at the molecular level. Tandem mass spectrometry of the isolated Hermes body from rat epididymal sperm characterized 1511 proteins, 43 of which were localized to the structure in situ by light microscopy and two by quantitative electron microscopy localization. Glucose transporter 3 (GLUT-3) glycolytic enzymes, selected membrane traffic and cytoskeletal proteins were highly abundant and concentrated in the Hermes body. By electron microscope gold antibody labelling, the Golgi trafficking protein TMED7/p27 localized to unstacked flattened cisternae of the Hermes body, as did GLUT-3, the most abundant protein. Its biogenesis was deduced through the mapping of protein expression for all 43 proteins during male germ cell differentiation in the testis. It is at the terminal step 19 of spermiogenesis that the 43 characteristic proteins accumulated in the nascent Hermes body.


Asunto(s)
Actinas/metabolismo , Membrana Celular/metabolismo , Epidídimo/metabolismo , Glucosa/metabolismo , Complejo de la Endopetidasa Proteasomal/metabolismo , Espermatozoides/metabolismo , Tubulina (Proteína)/metabolismo , Animales , Transporte Biológico , Movimiento Celular , Citoplasma/metabolismo , Retículo Endoplásmico/metabolismo , Glucólisis , Aparato de Golgi/metabolismo , Masculino , Proteínas de la Membrana/metabolismo , Factores de Elongación de Péptidos/metabolismo , Transporte de Proteínas , Ratas , Proteínas Ribosómicas/metabolismo , Células de Sertoli/metabolismo , Espermátides/metabolismo
13.
Mol Biol Cell ; 26(22): 4015-32, 2015 Nov 05.
Artículo en Inglés | MEDLINE | ID: mdl-25808494

RESUMEN

The molecular basis of changes in structure, cellular location, and function of the Golgi apparatus during male germ cell differentiation is unknown. To deduce cognate Golgi proteins, we isolated germ cell Golgi fractions, and 1318 proteins were characterized, with 20 localized in situ. The most abundant protein, GL54D of unknown function, is characterized as a germ cell-specific Golgi-localized type II integral membrane glycoprotein. TM9SF3, also of unknown function, was revealed to be a universal Golgi marker for both somatic and germ cells. During acrosome formation, several Golgi proteins (GBF1, GPP34, GRASP55) localize to both the acrosome and Golgi, while GL54D, TM9SF3, and the Golgi trafficking protein TMED7/p27 are segregated from the acrosome. After acrosome formation, GL54D, TM9SF3, TMED4/p25, and TMED7/p27 continue to mark Golgi identity as it migrates away from the acrosome, while the others (GBF1, GPP34, GRASP55) remain in the acrosome and are progressively lost in later steps of differentiation. Cytoplasmic HSP70.2 and the endoplasmic reticulum luminal protein-folding enzyme PDILT are also Golgi recruited but only during acrosome formation. This resource identifies abundant Golgi proteins that are expressed differentially during mitosis, meiosis, and postacrosome Golgi migration, including the last step of differentiation.


Asunto(s)
Aparato de Golgi/metabolismo , Espermatozoides/metabolismo , Testículo/metabolismo , Acrosoma/metabolismo , Animales , Diferenciación Celular/fisiología , Movimiento Celular/fisiología , Retículo Endoplásmico/metabolismo , Células Hep G2 , Humanos , Masculino , Glicoproteínas de Membrana/metabolismo , Proteínas de la Membrana , Transporte de Proteínas , Ratas , Ratas Sprague-Dawley , Espermátides/metabolismo , Espermatogénesis
14.
PLoS Genet ; 10(2): e1004109, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24516399

RESUMEN

The DAF-16/FoxO transcription factor controls growth, metabolism and aging in Caenorhabditis elegans. The large number of genes that it regulates has been an obstacle to understanding its function. However, recent analysis of transcript and chromatin profiling implies that DAF-16 regulates relatively few genes directly, and that many of these encode other regulatory proteins. We have investigated the regulation by DAF-16 of genes encoding the AMP-activated protein kinase (AMPK), which has α, ß and γ subunits. C. elegans has 5 genes encoding putative AMP-binding regulatory γ subunits, aakg-1-5. aakg-4 and aakg-5 are closely related, atypical isoforms, with orthologs throughout the Chromadorea class of nematodes. We report that ∼75% of total γ subunit mRNA encodes these 2 divergent isoforms, which lack consensus AMP-binding residues, suggesting AMP-independent kinase activity. DAF-16 directly activates expression of aakg-4, reduction of which suppresses longevity in daf-2 insulin/IGF-1 receptor mutants. This implies that an increase in the activity of AMPK containing the AAKG-4 γ subunit caused by direct activation by DAF-16 slows aging in daf-2 mutants. Knock down of aakg-4 expression caused a transient decrease in activation of expression in multiple DAF-16 target genes. This, taken together with previous evidence that AMPK promotes DAF-16 activity, implies the action of these two metabolic regulators in a positive feedback loop that accelerates the induction of DAF-16 target gene expression. The AMPK ß subunit, aakb-1, also proved to be up-regulated by DAF-16, but had no effect on lifespan. These findings reveal key features of the architecture of the gene-regulatory network centered on DAF-16, and raise the possibility that activation of AMP-independent AMPK in nutritionally replete daf-2 mutant adults slows aging in C. elegans. Evidence of activation of AMPK subunits in mammals suggests that such FoxO-AMPK interactions may be evolutionarily conserved.


Asunto(s)
Proteínas Quinasas Activadas por AMP/metabolismo , Envejecimiento/genética , Proteínas de Caenorhabditis elegans/genética , Factor I del Crecimiento Similar a la Insulina/genética , Insulina/metabolismo , Factores de Transcripción/genética , Proteínas Quinasas Activadas por AMP/genética , Animales , Caenorhabditis elegans , Proteínas de Caenorhabditis elegans/metabolismo , Factores de Transcripción Forkhead , Regulación del Desarrollo de la Expresión Génica , Redes Reguladoras de Genes , Longevidad/genética , Isoformas de Proteínas/genética , Receptor de Insulina/genética , Transducción de Señal/genética , Factores de Transcripción/metabolismo , Activación Transcripcional/genética
15.
Aging (Albany NY) ; 6(2): 98-117, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24531613

RESUMEN

In C. elegans, increased lifespan in daf-2 insulin/IGF-1 receptor mutants is accompanied by up-regulation of the MDL-1 Mad basic helix-loop-helix leucine zipper transcription factor. Here we describe the role of mdl-1 in C. elegans germline proliferation and aging. The deletion allele mdl-1(tm311) shortened lifespan, and did so significantly more so in long-lived daf-2 mutants implying that mdl-1(+) contributes to effects of daf-2 on lifespan. mdl-1 mutant hermaphrodites also lay increased numbers of unfertilized oocytes. During aging, unfertilized oocytes in the uterus develop into tumors, whose development was accelerated by mdl-1(tm311). Opposite phenotypes were seen in daf-2 mutants, i.e. mdl-1 and daf-2 mutant germlines are hyperplastic and hypoplastic, respectively. Thus, MDL-1, like its mammalian orthologs, is an inhibitor of cell proliferation and growth that slows progression of an age-related pathology in C. elegans (uterine tumors). In addition, intestine-limited rescue of mdl-1 increased lifespan but not to wild type levels. Thus, mdl-1 likely acts both in the intestine and the germline to influence age-related mortality.


Asunto(s)
Envejecimiento/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/metabolismo , Proteínas de Unión al ADN/metabolismo , Factores de Transcripción/metabolismo , Animales , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Proteínas de Unión al ADN/genética , Femenino , Factores de Transcripción Forkhead , Genes myc , Hiperplasia , Hipertrofia , Mucosa Intestinal/metabolismo , Oocitos/crecimiento & desarrollo , Neoplasias Uterinas/genética
16.
Contemp Nurse ; 45(2): 228-33, 2013 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24299251

RESUMEN

This research aimed to describe the number and type of residents admitted to emergency departments (EDs) over 2 years; and to explore nurses' perceptions of the reasons why residential aged care facility (RACF) residents are referred to EDs. The research objective was addressed in a retrospective exploratory study using data on admissions to EDs from RACFs (N = 3,094) at the participating organisation over a 2-year period, and interview data on seven RACF and four ED nurses' perceptions of the issues involved. Most residents presenting at EDs required urgent medical attention. Major themes identified by RACF and ED nurses included issues related to staff competency, availability of general practitioners, lack of equipment in RACFs, residents and family members requesting referrals, communication difficulties, and poor attitudes towards RACF staff. There is a need to use strategies to detect residents whose conditions are deteriorating and treat them promptly in RACFs.


Asunto(s)
Servicio de Urgencia en Hospital , Hogares para Ancianos , Derivación y Consulta , Femenino , Humanos , Masculino
17.
Cell ; 153(1): 228-39, 2013 Mar 28.
Artículo en Inglés | MEDLINE | ID: mdl-23540700

RESUMEN

The biguanide drug metformin is widely prescribed to treat type 2 diabetes and metabolic syndrome, but its mode of action remains uncertain. Metformin also increases lifespan in Caenorhabditis elegans cocultured with Escherichia coli. This bacterium exerts complex nutritional and pathogenic effects on its nematode predator/host that impact health and aging. We report that metformin increases lifespan by altering microbial folate and methionine metabolism. Alterations in metformin-induced longevity by mutation of worm methionine synthase (metr-1) and S-adenosylmethionine synthase (sams-1) imply metformin-induced methionine restriction in the host, consistent with action of this drug as a dietary restriction mimetic. Metformin increases or decreases worm lifespan, depending on E. coli strain metformin sensitivity and glucose concentration. In mammals, the intestinal microbiome influences host metabolism, including development of metabolic disease. Thus, metformin-induced alteration of microbial metabolism could contribute to therapeutic efficacy-and also to its side effects, which include folate deficiency and gastrointestinal upset.


Asunto(s)
Caenorhabditis elegans/efectos de los fármacos , Caenorhabditis elegans/microbiología , Ácido Fólico/metabolismo , Hipoglucemiantes/farmacología , Longevidad/efectos de los fármacos , Metformina/farmacología , Metionina/metabolismo , Adenilato Quinasa/metabolismo , Envejecimiento/efectos de los fármacos , Animales , Biguanidas/metabolismo , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Restricción Calórica , Proteínas de Unión al ADN/metabolismo , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Escherichia coli/metabolismo , Humanos , Hipoglucemiantes/metabolismo , Metagenoma , Metformina/metabolismo , Factores de Transcripción/metabolismo
18.
Cold Spring Harb Perspect Biol ; 5(1): a015073, 2013 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-23284051

RESUMEN

Enriched endoplasmic reticulum (ER) and Golgi membranes subjected to mass spectrometry have uncovered over a thousand different proteins assigned to the ER and Golgi apparatus of rat liver. This, in turn, led to the uncovering of several hundred proteins of poorly understood function and, through hierarchical clustering, showed that proteins distributed in patterns suggestive of microdomains in cognate organelles. This has led to new insights with respect to their intracellular localization and function. Another outcome has been the critical testing of the cisternal maturation hypothesis showing overwhelming support for a predominant role of COPI vesicles in the transport of resident proteins of the ER and Golgi apparatus (as opposed to biosynthetic cargo). Here we will discuss new insights gained and also highlight new avenues undertaken to further explore the cell biology of the ER and the Golgi apparatus through tandem mass spectrometry.


Asunto(s)
Retículo Endoplásmico/fisiología , Aparato de Golgi/fisiología , Animales , Calnexina/metabolismo , Biología Celular , Separación Celular , Análisis por Conglomerados , Retículo Endoplásmico/metabolismo , Aparato de Golgi/metabolismo , Humanos , Transporte de Proteínas , Proteómica/métodos , Ratas , Espectrometría de Masas en Tándem
19.
Free Radic Biol Med ; 52(9): 1903-10, 2012 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-22406322

RESUMEN

Organochalcogens have been widely studied given their antioxidant activity, which confers neuroprotection, antiulcer, and antidiabetic properties. Given the complexity of mammalian models, understanding the cellular and molecular effects of organochalcogens has been hampered. The nematode worm Caenorhabditis elegans is an alternative experimental model that affords easy genetic manipulations, green fluorescent protein tagging, and in vivo live analysis of toxicity. We previously showed that manganese (Mn)-exposed worms exhibit oxidative-stress-induced neurodegeneration and life-span reduction. Here we use Mn-exposed worms as a model for an oxidatively challenged organism to investigate the underlying mechanisms of organochalcogen antioxidant properties. First, we recapitulate in C. elegans the effects of organochalcogens formerly observed in mice, including their antioxidant activity. This is followed by studies on the ability of these compounds to afford protection against Mn-induced toxicity. Diethyl-2-phenyl-2-tellurophenyl vinyl phosphonate (DPTVP) was the most efficacious compound, fully reversing the Mn-induced reduction in survival and life span. Ebselen was also effective, reversing the Mn-induced reduction in survival and life span, but to a lesser extent compared with DPTVP. DPTVP also lowered Mn-induced increases in oxidant levels, indicating that the increased survival associated with exposure to this compound is secondary to a decrease in oxidative stress. Furthermore, DPTVP induced nuclear translocation of the transcriptional factor DAF-16/FOXO, which regulates stress responsiveness and aging in worms. Our findings establish that the organochalcogens DPTVP and ebselen act as antiaging agents in a model of Mn-induced toxicity and aging by regulating DAF-16/FOXO signaling and attenuating oxidative stress.


Asunto(s)
Caenorhabditis elegans/efectos de los fármacos , Manganeso/toxicidad , Compuestos de Organoselenio/farmacología , Estrés Oxidativo/efectos de los fármacos , Telurio/farmacología , Animales , Dosificación Letal Mediana , Microscopía Fluorescente , Especies Reactivas de Oxígeno/metabolismo
20.
Mutat Res ; 731(1-2): 140-4, 2012 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-22197482

RESUMEN

DNA double-strand breaks (DSBs) are most often repaired by two pathways in mammalian cells, homologous recombination or non-homologous end joining. Biochemical and genetic studies showed that DSBs can also be joined via microhomology-mediated end joining (MHEJ), which is always mutagenic and may result in diseases, such as cancer. In this study we established a human cell-based reporter system to determine the prevalence of MHEJ events and factors that modulate MHEJ. A nonfunctional puromycin acetyltransferase (Pac) gene, disrupted by an insertion flanked by two microhomologous repeats, was integrated into chromosomes of human HT1080 cells. Repair of DSBs via MHEJ using the repeats resulted in deletion of the insertion and restoration of the Pac gene function, thus rendering the cells puromycin resistant. Our results showed that MHEJ spontaneously occurs at the reporter locus (loci), manifested by formation of puromycin resistant (puro(r)) colonies after culturing reporter cells in medium containing puromycin. The frequency of puro(r) cells can be greatly increased by site-directed DSB inside the insertion. Our results also demonstrated that the frequency of puro(r) cells is affected by the length of the repeat and by the size of the intervening sequence. Thus, this cell-based assay provides a platform for evaluating factors modulating in vivo MHEJ.


Asunto(s)
Roturas del ADN de Doble Cadena , Reparación del ADN por Unión de Extremidades , Línea Celular Tumoral , Resistencia a Antineoplásicos , Técnicas Genéticas , Humanos , Puromicina/farmacología
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