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1.
J Cell Biol ; 223(8)2024 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-38775785

RESUMO

Autophagy is an important metabolic pathway that can non-selectively recycle cellular material or lead to targeted degradation of protein aggregates or damaged organelles. Autophagosome formation starts with autophagy factors accumulating on lipid vesicles containing ATG9. These phagophores attach to donor membranes, expand via ATG2-mediated lipid transfer, capture cargo, and mature into autophagosomes, ultimately fusing with lysosomes for their degradation. Autophagy can be activated by nutrient stress, for example, by a reduction in the cellular levels of amino acids. In contrast, how autophagy is regulated by low cellular ATP levels via the AMP-activated protein kinase (AMPK), an important therapeutic target, is less clear. Using live-cell imaging and an automated image analysis pipeline, we systematically dissect how nutrient starvation regulates autophagosome biogenesis. We demonstrate that glucose starvation downregulates autophagosome maturation by AMPK-mediated inhibition of phagophore tethering to donor membrane. Our results clarify AMPKs regulatory role in autophagy and highlight its potential as a therapeutic target to reduce autophagy.


Assuntos
Proteínas Quinases Ativadas por AMP , Autofagossomos , Autofagia , Humanos , Proteínas Quinases Ativadas por AMP/metabolismo , Autofagossomos/metabolismo , Glucose/metabolismo , Linhagem Celular
2.
Methods Mol Biol ; 2668: 23-32, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37140787

RESUMO

Current methods for characterizing the biodistribution of extracellular vesicles (EVs) are not sensitive enough to track EVs in vivo, despite significant advances over the past decade. Commonly used lipophilic fluorescent dyes are convenient, but lack specificity and yield inaccurate spatiotemporal images in the long-term tracking of EVs. In contrast, protein-based fluorescent or bioluminescent EV reporters have more accurately revealed their distribution in cells and mouse models. Here, we describe a red-shifted bioluminescence resonance energy transfer (BRET) EV reporter, PalmReNL, to analyze the trafficking of small EVs (<200 nm; sEVs) and medium/large EVs (>200 nm; m/lEVs) in mice. Its advantages are that (i) background signals in bioluminescence imaging (BLI) are negligible and (ii) the photons PalmReNL emits have spectral wavelengths longer than 600 nm and can more efficiently penetrate tissues than reporters emitting shorter wavelength light.


Assuntos
Vesículas Extracelulares , Animais , Camundongos , Distribuição Tecidual , Vesículas Extracelulares/metabolismo , Proteínas/metabolismo , Diagnóstico por Imagem , Transferência de Energia
3.
J Cell Biol ; 222(7)2023 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-37115157

RESUMO

Autophagy is a catabolic pathway required for the recycling of cytoplasmic materials. To define the mechanisms underlying autophagy it is critical to quantitatively characterize the dynamic behavior of autophagy factors in living cells. Using a panel of cell lines expressing HaloTagged autophagy factors from their endogenous loci, we analyzed the abundance, single-molecule dynamics, and autophagosome association kinetics of autophagy proteins involved in autophagosome biogenesis. We demonstrate that autophagosome formation is inefficient and ATG2-mediated tethering to donor membranes is a key commitment step in autophagosome formation. Furthermore, our observations support the model that phagophores are initiated by the accumulation of autophagy factors on mobile ATG9 vesicles, and that the ULK1 complex and PI3-kinase form a positive feedback loop required for autophagosome formation. Finally, we demonstrate that the duration of autophagosome biogenesis is ∼110 s. In total, our work provides quantitative insight into autophagosome biogenesis and establishes an experimental framework to analyze autophagy in human cells.


Assuntos
Autofagossomos , Proteínas Relacionadas à Autofagia , Proteínas de Membrana , Humanos , Autofagossomos/metabolismo , Autofagia/genética , Proteínas Relacionadas à Autofagia/genética , Proteínas Relacionadas à Autofagia/metabolismo , Macroautofagia , Proteínas de Membrana/metabolismo
4.
bioRxiv ; 2023 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-37808644

RESUMO

Autophagy is an important metabolic pathway that can non-selectively recycle cellular material or lead to targeted degradation of protein aggregates or damaged organelles. Autophagosome formation starts with autophagy factors accumulating on lipid vesicles containing ATG9. These phagophores attach to donor membranes, expand via ATG2-mediated lipid transfer, capture cargo, and mature into autophagosomes, ultimately fusing with lysosomes for their degradation. Autophagy can be activated by nutrient stress, for example by a reduction in the cellular levels of amino acids. In contrast, how autophagy is regulated by low cellular ATP levels via the AMP-activated protein kinase (AMPK), an important therapeutic target, is less clear. Using live-cell imaging and an automated image analysis pipeline, we systematically dissect how nutrient starvation regulates autophagosome biogenesis. We demonstrate that glucose starvation downregulates autophagosome maturation by AMPK mediated inhibition of phagophores tethering to donor membranes. Our results clarify AMPK's regulatory role in autophagy and highlight its potential as a therapeutic target to reduce autophagy.

5.
Cell Rep ; 42(6): 112577, 2023 06 27.
Artigo em Inglês | MEDLINE | ID: mdl-37267110

RESUMO

Localization of a variety of RNAs to non-membrane-bound cellular compartments such as nucleoli and Cajal bodies is critical for their stability and function. The molecular mechanisms that underly the recruitment and exclusion of RNAs from these phase-separated organelles is incompletely understood. Telomerase is a ribonucleoprotein composed of the reverse transcriptase protein telomerase reverse transcriptase (TERT), the telomerase RNA (TR), and several auxiliary proteins, including TCAB1. Here we show that in the absence of TCAB1, a large fraction of TR is tightly bound to the nucleolus, while TERT is largely excluded from the nucleolus, reducing telomerase assembly. This suggests that nuclear compartmentalization by the non-membrane-bound nucleolus counteracts telomerase assembly, and TCAB1 is required to retain TR in the nucleoplasm. Our work provides insight into the mechanism and functional consequences of RNA recruitment to organelles formed by phase separation and demonstrates that TCAB1 plays an important role in telomerase assembly.


Assuntos
Telomerase , Nucléolo Celular/metabolismo , Núcleo Celular/metabolismo , RNA/metabolismo , Telomerase/metabolismo , Humanos , Células HeLa
6.
Vaccines (Basel) ; 11(3)2023 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-36992223

RESUMO

Under physiological conditions, phosphatidylserine (PS) predominantly localizes to the cytosolic leaflet of the plasma membrane of cells. During apoptosis, PS is exposed on the cell surface and serves as an "eat-me" signal for macrophages to prevent releasing self-immunogenic cellular components from dying cells which could potentially lead to autoimmunity. However, increasing evidence indicates that viable cells can also expose PS on their surface. Interestingly, tumor cell-derived extracellular vesicles (EVs) externalize PS. Recent studies have proposed PS-exposing EVs as a potential biomarker for the early detection of cancer and other diseases. However, there are confounding results regarding subtypes of PS-positive EVs, and knowledge of PS exposure on the EV surface requires further elucidation. In this study, we enriched small EVs (sEVs) and medium/large EVs (m/lEVs) from conditioned media of breast cancer cells (MDA-MB-231, MDA-MB-468) and non-cancerous cells (keratinocytes, fibroblasts). Since several PS-binding molecules are available to date, we compared recombinant proteins of annexin A5 and the carboxylated glutamic acid domain of Protein S (GlaS), also specific for PS, to detect PS-exposing EVs. Firstly, PS externalization in each EV fraction was analyzed using a bead-based EV assay, which combines EV capture using microbeads and analysis of PS-exposing EVs by flow cytometry. The bulk EV assay showed higher PS externalization in m/lEVs derived from MDA-MB-468 cells but not from MDA-MB-231 cells, while higher binding of GlaS was also observed in m/lEVs from fibroblasts. Second, using single EV flow cytometry, PS externalization was also analyzed on individual sEVs and m/lEVs. Significantly higher PS externalization was detected in m/lEVs (annexin A1+) derived from cancer cells compared to m/lEVs (annexin A1+) from non-cancerous cells. These results emphasize the significance of PS-exposing m/lEVs (annexin A1+) as an undervalued EV subtype for early cancer detection and provide a better understanding of PS externalization in disease-associated EV subtypes.

7.
Biol Reprod ; 86(3): 76, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22190703

RESUMO

Reproductive health of humans and animals exposed to daily irradiants from solar/cosmic particles remains largely understudied. We evaluated the sensitivities of bovine and mouse oocytes to bombardment by krypton-78 (1 Gy) or ultraviolet B (UV-B; 100 microjoules). Mouse oocytes responded to irradiation by undergoing massive activation of caspases, rapid loss of energy without cytochrome-c release, and subsequent necrotic death. In contrast, bovine oocytes became positive for annexin-V, exhibited cytochrome-c release, and displayed mild activation of caspases and downstream DNAses but with the absence of a complete cell death program; therefore, cytoplasmic fragmentation was never observed. However, massive cytoplasmic fragmentation and increased DNA damage were induced experimentally by both inhibiting RAD51 and increasing caspase 3 activity before irradiation. Microinjection of recombinant human RAD51 prior to irradiation markedly decreased both cytoplasmic fragmentation and DNA damage in both bovine and mouse oocytes. RAD51 response to damaged DNA occurred faster in bovine oocytes than in mouse oocytes. Therefore, we conclude that upon exposure to irradiation, bovine oocytes create a physiologically indeterminate state of partial cell death, attributed to rapid induction of DNA repair and low activation of caspases. The persistence of these damaged cells may represent an adaptive mechanism with potential implications for livestock productivity and long-term health risks associated with human activity in space.


Assuntos
Apoptose/efeitos da radiação , Oócitos/efeitos da radiação , Rad51 Recombinase/fisiologia , Radiação Ionizante , Animais , Anexina A5/metabolismo , Caspase 3/metabolismo , Bovinos , Células Cultivadas , Citocromos c/metabolismo , Dano ao DNA/efeitos da radiação , Feminino , Camundongos , Modelos Animais , Oócitos/citologia , Oócitos/metabolismo
8.
Reproduction ; 143(1): 1-10, 2012 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-22046054

RESUMO

Maternal aging adversely affects oocyte quality (function and developmental potential) and consequently lowers pregnancy rates while increasing spontaneous abortions. Substantial evidence, especially from egg donation studies, implicates the decreased quality of an aging oocyte as a major factor in the etiology of female infertility. Nevertheless, the cellular and molecular mechanisms responsible for the decreased oocyte quality with advanced maternal aging are not fully characterized. Herein we present information in the published literature and our own data to support the hypothesis that during aging induced decreases in mitochondrial ceramide levels and associated alterations in mitochondrial structure and function are prominent elements contributing to reduced oocyte quality. Hence, by examining the molecular determinants that underlie impairments in oocyte mitochondria, we expect to sieve to a better understanding of the mechanistic anatomy of oocyte aging.


Assuntos
Envelhecimento/metabolismo , Ceramidas/metabolismo , Oócitos/metabolismo , Animais , Transporte Biológico Ativo , Feminino , Fertilidade/fisiologia , Humanos , Idade Materna , Mitocôndrias/metabolismo , Modelos Biológicos , Oócitos/crescimento & desenvolvimento , Gravidez , Proteínas Serina-Treonina Quinases/metabolismo
9.
Adv Genet (Hoboken) ; 3(1): 2100055, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36619349

RESUMO

Cancer cells produce heterogeneous extracellular vesicles (EVs) as mediators of intercellular communication. This study focuses on a novel method to image EV subtypes and their biodistribution in vivo. A red-shifted bioluminescence resonance energy transfer (BRET) EV reporter is developed, called PalmReNL, which allows for highly sensitive EV tracking in vitro and in vivo. PalmReNL enables the authors to study the common surface molecules across EV subtypes that determine EV organotropism and their functional differences in cancer progression. Regardless of injection routes, whether retro-orbital or intraperitoneal, PalmReNL positive EVs, isolated from murine mammary carcinoma cells, localized to the lungs. The early appearance of metastatic foci in the lungs of mammary tumor-bearing mice following multiple intraperitoneal injections of the medium and large EV (m/lEV)-enriched fraction derived from mammary carcinoma cells is demonstrated. In addition, the results presented here show that tumor cell-derived m/lEVs act on distant tissues through upregulating LC3 expression within the lung.

10.
J Cell Biochem ; 112(9): 2403-11, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21538476

RESUMO

Type I (T1) diabetes is an autoimmune and metabolic disease associated with bone loss. Bone formation and density are decreased in T1-diabetic mice. Correspondingly, the number of TUNEL positive, dying osteoblasts increases in bones of T1-diabetic mice. Moreover, two known mediators of osteoblast death, TNFα and ROS, are increased in T1-diabetic bone. TNFα and oxidative stress are known to activate caspase-2, a factor involved in the extrinsic apoptotic pathway. Therefore, we investigated the requirement of caspase-2 for diabetes-induced osteoblast death and bone loss. Diabetes was induced in 16-week old C57BL/6 caspase-2 deficient mice and their wild type littermates and markers of osteoblast death, bone formation and resorption, and marrow adiposity were examined. Despite its involvement in extrinsic cell death, deficiency of caspase-2 did not prevent or reduce diabetes-induced osteoblast death as evidenced by a twofold increase in TUNEL positive osteoblasts in both mouse genotypes. Similarly, deficiency of caspase-2 did not prevent T1-diabetes induced bone loss in trabecular bone (BV/TV decreased by 30 and 50%, respectively) and cortical bone (decreased cortical thickness and area with increased marrow area). Interestingly, at this age, differences in bone parameters were not seen between genotypes. However, caspase-2 deficiency attenuated diabetes-induced bone marrow adiposity and adipocyte gene expression. Taken together, our data suggest that caspase-2 deficiency may play a role in promoting marrow adiposity under stress or disease conditions, but it is not required for T1-diabetes induced bone loss.


Assuntos
Adiposidade , Medula Óssea/patologia , Caspase 2/deficiência , Diabetes Mellitus Experimental/patologia , Fosfatase Ácida/genética , Fosfatase Ácida/metabolismo , Animais , Apoptose , Desmineralização Patológica Óssea/etiologia , Medula Óssea/metabolismo , Caspase 2/genética , Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/fisiopatologia , Proteínas de Ligação a Ácido Graxo/genética , Proteínas de Ligação a Ácido Graxo/metabolismo , Fêmur/diagnóstico por imagem , Fêmur/patologia , Expressão Gênica , Isoenzimas/genética , Isoenzimas/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Osteoblastos/metabolismo , Osteoblastos/patologia , Osteocalcina/genética , Osteocalcina/metabolismo , Osteoclastos/metabolismo , Osteoclastos/patologia , PPAR gama/genética , PPAR gama/metabolismo , Deleção de Sequência , Fosfatase Ácida Resistente a Tartarato , Microtomografia por Raio-X , Proteína X Associada a bcl-2/genética , Proteína X Associada a bcl-2/metabolismo
11.
Int J Dev Biol ; 63(6-7): 287-293, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31250912

RESUMO

During somatic cell nuclear transfer (SCNT), egg activation is required to initiate embryonic development. In zebrafish cloning, the reconstructed egg is activated by exposing it to hypotonic water. Egg activation using water-only is not capable of activating the same intracellular calcium release as fertilization which is required for proper embryonic development. Here we test whether the use of soluble sperm extract (SSE) can properly modulate the activation of reconstructed eggs during SCNT. We microinjected SSE from genomic-inactivated zebrafish sperm into unfertilized eggs and reconstructed eggs right after somatic cell nuclear transfer. We also evaluated the most effective approach for SSE microinjection. Microinjection of SSE (with 0.68 mg/ml of protein concentration) into non-activated eggs through the micropyle induced parthenogenetic development beyond the blastula stage, whereas all water-only activated eggs failed to enter the cleavage period. Microinjection of SSE at 1 mg/ml of protein concentration into non-activated reconstructed egg improved the developmental rate of cloned embryos in comparison to non-injected control clones. The cumulative survival time of cloned embryos injected with SSE was significantly longer than reconstructed eggs activated following sham injection (P<0.01). No significant difference was found among controls (P=0.32). SSE benefits both parthenogenesis and the survival cloned embryos which have never been reported in zebrafish. Further work is necessary to define the functional component(s) of SSE as well as the physiological pathway, to understand its principle of action and advance the utilization of SSE in cloning.


Assuntos
Embrião não Mamífero/citologia , Desenvolvimento Embrionário/genética , Técnicas de Transferência Nuclear , Óvulo/citologia , Partenogênese , Injeções de Esperma Intracitoplásmicas/métodos , Espermatozoides/citologia , Animais , Blastocisto/citologia , Blastocisto/fisiologia , Embrião não Mamífero/fisiologia , Masculino , Óvulo/fisiologia , Espermatozoides/fisiologia , Peixe-Zebra
12.
Sci Rep ; 9(1): 15525, 2019 10 29.
Artigo em Inglês | MEDLINE | ID: mdl-31664153

RESUMO

Male infertility might be caused by genetic and/or environmental factors that impair spermatogenesis and epididymal sperm maturation. Here we report that heterozygous deletion of the nuclear receptor coactivator-5 (Ncoa5) gene resulted in decreased motility and progression of spermatozoa in the cauda epididymis, leading to infertility in male mice. Light microscopic and ultrastructural analysis revealed morphological defects in the spermatozoa collected from the cauda epididymis of Ncoa5+/- mice. Immunohistochemistry showed that interleukin-6 (IL-6) expression in epithelial cells of Ncoa5+/- epididymis was higher than wild type counterparts. Furthermore, heterozygous deletion of Il-6 gene in Ncoa5+/- male mice partially improved spermatozoa motility and moderately rescued infertility phenotype. Our results uncover a previously unknown physiological role of NCOA5 in the regulation of epididymal sperm maturation and suggest that NCOA5 deficiency could cause male infertility through increased IL-6 expression in epididymis.


Assuntos
Regulação da Expressão Gênica , Infertilidade Masculina , Interleucina-6/biossíntese , Coativadores de Receptor Nuclear/deficiência , Motilidade dos Espermatozoides/genética , Espermatozoides , Animais , Epididimo/metabolismo , Epididimo/patologia , Haploinsuficiência , Infertilidade Masculina/genética , Infertilidade Masculina/metabolismo , Infertilidade Masculina/patologia , Interleucina-6/genética , Masculino , Camundongos , Camundongos Knockout , Coativadores de Receptor Nuclear/metabolismo , Espermatozoides/metabolismo , Espermatozoides/patologia
13.
Mol Cancer Ther ; 18(12): 2331-2342, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31451563

RESUMO

An emerging approach for cancer treatment employs the use of extracellular vesicles, specifically exosomes and microvesicles, as delivery vehicles. We previously demonstrated that microvesicles can functionally deliver plasmid DNA to cells and showed that plasmid size and sequence, in part, determine the delivery efficiency. In this study, delivery vehicles comprised of microvesicles loaded with engineered minicircle (MC) DNA that encodes prodrug converting enzymes developed as a cancer therapy in mammary carcinoma models. We demonstrated that MCs can be loaded into shed microvesicles with greater efficiency than their parental plasmid counterparts and that microvesicle-mediated MC delivery led to significantly higher and more prolonged transgene expression in recipient cells than microvesicles loaded with the parental plasmid. Microvesicles loaded with MCs encoding a thymidine kinase (TK)/nitroreductase (NTR) fusion protein produced prolonged TK-NTR expression in mammary carcinoma cells. In vivo delivery of TK-NTR and administration of prodrugs led to the effective killing of both targeted cells and surrounding tumor cells via TK-NTR-mediated conversion of codelivered prodrugs into active cytotoxic agents. In vivo evaluation of the bystander effect in mouse models demonstrated that for effective therapy, at least 1% of tumor cells need to be delivered with TK-NTR-encoding MCs. These results suggest that MC delivery via microvesicles can mediate gene transfer to an extent that enables effective prodrug conversion and tumor cell death such that it comprises a promising approach to cancer therapy.


Assuntos
DNA/uso terapêutico , Terapia Genética/métodos , Pró-Fármacos/uso terapêutico , Animais , Feminino , Humanos , Camundongos , Transfecção
14.
FASEB J ; 19(7): 860-2, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15728664

RESUMO

An age-dependent acceleration of apoptosis occurs in female germ cells (oocytes), and this requires communication between the oocyte and its surrounding somatic (cumulus) cells. Here we show in aged mice that ceramide is translocated from cumulus cells into the adjacent oocyte and induces germ cell apoptosis that can be prevented by sphingosine-1-phosphate. Trafficking of ceramide requires gap junction-dependent communication between the cumulus cells and the oocyte as well as intact lipid rafts. Further, the occurrence of the elevated incidence of apoptosis in oocytes of aged females is concomitant with an enhanced sensitivity of the oocyte to a spike in cytosolic ceramide levels, as well as increased bax mRNA and Bax protein levels. Thus, the force driving the age-related increase in female germ cell death is multifactorial, but changes in the intercellular trafficking of ceramide, along with hypersensitivity of oocytes to ceramide, are key factors in this process.


Assuntos
Envelhecimento/fisiologia , Apoptose/fisiologia , Ceramidas/fisiologia , Oócitos/fisiologia , Animais , Apoptose/efeitos dos fármacos , Transporte Biológico , Comunicação Celular , Células Cultivadas , Ceramidas/análise , Ceramidas/deficiência , Ceramidas/farmacologia , Citocromos c/metabolismo , Citosol/química , Feminino , Filipina/farmacologia , Junções Comunicantes/efeitos dos fármacos , Junções Comunicantes/fisiologia , Ácido Glicirretínico/farmacologia , Lisofosfolipídeos/farmacologia , Microdomínios da Membrana/efeitos dos fármacos , Microdomínios da Membrana/fisiologia , Camundongos , Camundongos Endogâmicos ICR , Camundongos Knockout , Oócitos/química , Oócitos/ultraestrutura , Folículo Ovariano/citologia , Folículo Ovariano/fisiologia , RNA Mensageiro/análise , Esfingosina/análogos & derivados , Esfingosina/farmacologia , Proteína X Associada a bcl-2/análise , Proteína X Associada a bcl-2/genética
16.
Endocrinology ; 143(2): 615-20, 2002 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11796517

RESUMO

We recently reported that a targeted disruption of the gene encoding the aromatic hydrocarbon receptor (AHR) in mice reduces fetal oocyte apoptosis, leading to a 2-fold increase in the number of primordial follicles endowed at birth. Although the identity of the natural ligand(s) for the AHR remains to be unequivocally established, these findings indicate that the level of AHR function is an important physiological determinant of how many oocytes will succumb to apoptosis during development of the fetal ovaries. Furthermore, the AHR is a well established receptor for polycyclic aromatic hydrocarbons (PAHs), a class of ubiquitous environmental chemicals known to cause the death of female germ cells in fetal life. Given the possibility that the AHR serves as a key mediator of fetal oocyte death under both physiological and pathological situations, this study was conducted to more fully examine the impact of PAH-AHR interaction on fetal ovarian germ cells. In addition, experiments were designed to begin identification of the mechanism(s) by which ligand activation of the AHR induces prenatal oocyte depletion after transplacental exposure of fetuses to PAHs in vivo. Embryonic d 13.5 murine fetal ovaries cultured in the presence of PAHs exhibited a high level of germ cell loss via apoptosis that was prevented by the selective AHR antagonist, alpha-napthoflavone (ANF). Immunohistochemical analysis revealed an accumulation of Bax protein in germ cells of fetal ovaries exposed to PAHs before the onset of apoptosis, whereas cotreatment with ANF inhibited the induction of Bax expression. The functional importance of increased Bax expression to the cytotoxic response was confirmed by findings that fetal ovarian germ cell loss caused by in utero exposure of wild-type female fetuses to PAHs was not observed in Bax-deficient female fetuses exposed in parallel. We conclude that a central role exists for the AHR in transducing the actions of PAHs in fetal ovarian germ cells, and that the proapoptotic Bcl-2 family member, Bax, is a required mediator of PAH-induced oocyte loss in female fetuses exposed to PAHs in utero.


Assuntos
Apoptose/genética , Células Germinativas/fisiologia , Ovário/fisiologia , Proteínas Proto-Oncogênicas c-bcl-2/fisiologia , Proteínas Proto-Oncogênicas/fisiologia , Receptores de Hidrocarboneto Arílico/genética , Fatores de Transcrição/genética , 9,10-Dimetil-1,2-benzantraceno/farmacologia , Animais , Células Cultivadas , Feminino , Feto , Células Germinativas/efeitos dos fármacos , Ligantes , Camundongos , Camundongos Endogâmicos C57BL , Oócitos/efeitos dos fármacos , Ovário/citologia , Ovário/embriologia , Hidrocarbonetos Policíclicos Aromáticos/farmacologia , Proteínas Proto-Oncogênicas/biossíntese , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas c-bcl-2/biossíntese , Proteínas Proto-Oncogênicas c-bcl-2/genética , Receptores de Hidrocarboneto Arílico/biossíntese , Proteína X Associada a bcl-2
17.
Endocrinology ; 144(1): 69-74, 2003 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-12488331

RESUMO

The industrial chemical, 4-vinylcyclohexene diepoxide (VCD), kills oocytes within immature follicles in the ovaries of mice and rats and is considered a potential occupational health hazard. It has been reported that VCD-induced follicle loss occurs via a cell death process involving elevated expression of Bax, a proapoptotic Bcl-2 family member, and increased caspase-3-like activity. We have previously shown that oocytes lacking acid sphingomyelinase (ASMase; an enzyme that generates the proapoptotic stress sensor ceramide), the aromatic hydrocarbon receptor (Ahr), Bax, or caspase-2 are resistant to apoptosis induced by other chemical toxicants. Therefore, this study was designed to investigate the functional importance of ASMase, Ahr, Bax, and caspase-2 as well as the related executioner enzyme caspase-3 to VCD-induced ovotoxicity in mice using gene knockout technology. For each gene mutant mouse line, wild-type and homozygous-null female siblings derived from heterozygous matings were given once-daily ip injections of either vehicle (sesame oil) or VCD (80 mg/kg body weight) for 15 d (three or four mice per treatment group per genotype). Ovaries were collected 24 h after the final injection and analyzed for the total number of nonatretic primordial and primary follicles remaining per ovary. No differences in the extent of primordial or primary follicle destruction resulting from VCD exposure were observed in wild-type vs. ASMase- or Ahr-deficient mice. By contrast, the extent of VCD-induced primordial follicle depletion in Bax-deficient mice (45 +/- 11%) was significantly (P < 0.05) lower than that in wild-type females (85 +/- 2%). The extent of primary follicle loss in bax-null mice exposed to VCD (3 +/- 22%) was also significantly (P < 0.05) lower than that in their wild-type sisters (86 +/- 4%). In caspase-2-deficient mice, significantly (P < 0.05) fewer oocyte-containing primary follicles were destroyed by VCD (17 +/- 19%) vs. wild-type controls (71 +/- 6%); however, no significant difference in the extent of VCD-induced primordial follicle destruction was observed in caspase-2-null vs. wild-type females. Finally, in caspase-3-deficient mice, significantly (P < 0.05) fewer oocyte-containing primary follicles were destroyed by VCD (33 +/- 3%) vs. wild-type controls (71 +/- 2%); however, no significant difference in the extent of VCD-induced primordial follicle destruction was observed in caspase-3-null vs. wild-type females. We conclude that Bax, caspase-2, and caspase-3, but not ASMase or Ahr, are functionally important in VCD-induced follicle loss. However, as a loss of Bax, caspase-2, or caspase-3 function conveyed only partial protection from the ovotoxic effects of VCD, other cell death pathways that either function independently of Bax, caspase-2, and caspase-3 or are not apoptotic in nature are also involved.


Assuntos
Caspases/fisiologia , Cicloexanos/toxicidade , Folículo Ovariano/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-bcl-2 , Proteínas Proto-Oncogênicas/fisiologia , Animais , Apoptose/efeitos dos fármacos , Caspase 2 , Caspase 3 , Caspases/deficiência , Caspases/genética , Contagem de Células , Cicloexenos , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Oócitos/efeitos dos fármacos , Oócitos/enzimologia , Proteínas Proto-Oncogênicas/deficiência , Proteínas Proto-Oncogênicas/genética , Receptores de Hidrocarboneto Arílico/deficiência , Receptores de Hidrocarboneto Arílico/genética , Receptores de Hidrocarboneto Arílico/fisiologia , Especificidade da Espécie , Esfingomielina Fosfodiesterase/deficiência , Esfingomielina Fosfodiesterase/genética , Esfingomielina Fosfodiesterase/fisiologia , Proteína X Associada a bcl-2
18.
Mech Ageing Dev ; 134(1-2): 43-52, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23246342

RESUMO

In women as well as in mice, oocytes exhibit decreased developmental potential (oocyte quality) with advanced age. Our current data implicate alterations in the levels of oocyte ceramide and associated changes in mitochondrial function and structure as being prominent elements contributing to reduced oocyte quality. Both ROS levels and ATP content were significantly reduced in aged oocytes. The decreased in ROS levels are of intrigue because it is contrary to what has been previously reported. Lowered levels of both ROS and ATP indicate diminished mitochondrial function that was accompanied by alterations in mitochondrial structure. Interestingly, developmental potential of old oocytes was improved by microinjection of mitochondria isolated from young oocytes. Co-treatment of aged oocytes with ceramide and a cytoplasmic lipid carrier (l-carnitine) improved both mitochondrial morphology and function, and totally rescued spontaneous in vitro fragmentation. In addition, ceramide localization was altered in old oocytes possibly due to downregulation of the ceramide transport protein (CERT). However, knockdown of CERT alone was not sufficient to increase young oocyte's susceptibility to death, because the sequential manipulation of ceramide levels (its chronic decrease, followed by downregulation of CERT, and finally a ceramide spike) were all necessary to replicate the aging phenotype. These results indicate that oocyte aging is due to a multiplicity of events; and that with increasing biological age, changes in levels of both ceramide and its transport protein contribute to deterioration of oocyte mitochondrial structure and function. Hence, those changes may represent potential targets to manipulate when attempting to ameliorate aging phenotypes in germ cells.


Assuntos
Senescência Celular , Ceramidas/metabolismo , Mitocôndrias/metabolismo , Proteínas Mitocondriais/metabolismo , Oócitos/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Trifosfato de Adenosina/genética , Trifosfato de Adenosina/metabolismo , Animais , Carnitina/genética , Carnitina/metabolismo , Células Cultivadas , Ceramidas/genética , Feminino , Técnicas de Silenciamento de Genes , Humanos , Camundongos , Camundongos Endogâmicos ICR , Mitocôndrias/genética , Mitocôndrias/patologia , Proteínas Mitocondriais/genética , Oócitos/patologia , Proteínas Serina-Treonina Quinases/genética , Espécies Reativas de Oxigênio/metabolismo
19.
Stem Cells Dev ; 22(5): 735-49, 2013 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-23025754

RESUMO

Approximately 12.5% of all 9,920 extant bird species in the world are threatened with extinction, and yet conservation efforts through natural breeding of captive species continue to encounter difficulties. However, sperm cryopreservation and artificial insemination offer potential benefits over natural breeding, but their applicability is still limited in nondomestic species. In this study, we aimed to exploit the potential of germ cell xenotransplantation as an alternative tool for preserving germplasm of endangered birds. The study was designed to investigate whether transfer of either spermatogonia-enriched cell fraction (SEF) or crude testicular cell fraction (CTF) from adult Japanese quails (as a model for wild species) would result in recolonization of gamma-irradiated gonads of adult recipient chickens. One month after transplantation, 75% of recipients injected with SEF and 25% of recipients injected with CTF resumed spermatogenesis. However, it took more than 3 months for 33% of the negative controls to resume marginal production of sperm. Some SEF recipients produced more spermatozoa bearing head morphology compared with donor controls. DNA analysis using quail-specific primers did not detect donor's DNA in these recipients' semen. However, 6 months after xenotransplantation, presence of quail germ cells was demonstrated by polymerase chain reaction and by immunohistochemistry in 1 rooster injected with SEF. These findings indicate that spermatogonia from adult quails were capable of colonizing immunocompetent testis of adult chickens but failed to produce sufficient sperm. Despite this limitation, the present approach represents a potential conservation tool that may be used to rescue germ cells of endangered adult male birds.


Assuntos
Galinhas , Coturnix , Espermatogênese , Espermatogônias/transplante , Espermatozoides/transplante , Testículo/citologia , Transplante Heterólogo/veterinária , Animais , Cruzamento , Galinhas/fisiologia , Coturnix/fisiologia , Espécies em Perigo de Extinção , Feminino , Inseminação Artificial , Masculino , Espermatozoides/fisiologia
20.
PLoS One ; 6(3): e17877, 2011 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-21437292

RESUMO

To our knowledge, there is no report on long-term reproductive and developmental side effects in the offspring of mothers treated with a widely used chemotherapeutic drug such as doxorubicin (DXR), and neither is there information on transmission of any detrimental effects to several filial generations. Therefore, the purpose of the present paper was to examine the long-term effects of a single intraperitoneal injection of DXR on the reproductive and behavioral performance of adult female mice and their progeny. C57BL/6 female mice (generation zero; G0) were treated with either a single intraperitoneal injection of DXR (G0-DXR) or saline (G0-CON). Data were collected on multiple reproductive parameters and behavioral analysis for anxiety, despair and depression. In addition, the reproductive capacity and health of the subsequent six generations were evaluated. G0-DXR females developed despair-like behaviors; delivery complications; decreased primordial follicle pool; and early lost of reproductive capacity. Surprisingly, the DXR-induced effects in oocytes were transmitted transgenerationally; the most striking effects being observed in G4 and G6, constituting: increased rates of neonatal death; physical malformations; chromosomal abnormalities (particularly deletions on chromosome 10); and death of mothers due to delivery complications. None of these effects were seen in control females of the same generations. Long-term effects of DXR in female mice and their offspring can be attributed to genetic alterations or cell-killing events in oocytes or, presumably, to toxicosis in non-ovarian tissues. Results from the rodent model emphasize the need for retrospective and long-term prospective studies of survivors of cancer treatment and their offspring.


Assuntos
Antineoplásicos/efeitos adversos , Antineoplásicos/uso terapêutico , Hereditariedade/efeitos dos fármacos , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/farmacologia , Ansiedade/tratamento farmacológico , Atrofia , Comportamento Animal/efeitos dos fármacos , Deleção Cromossômica , Cromossomos de Mamíferos/genética , Doxorrubicina/administração & dosagem , Doxorrubicina/efeitos adversos , Doxorrubicina/farmacologia , Doxorrubicina/uso terapêutico , Feminino , Hereditariedade/genética , Hereditariedade/fisiologia , Humanos , Lisofosfolipídeos/farmacologia , Lisofosfolipídeos/uso terapêutico , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Miométrio/efeitos dos fármacos , Miométrio/patologia , Oócitos/efeitos dos fármacos , Folículo Ovariano/efeitos dos fármacos , Folículo Ovariano/patologia , Folículo Ovariano/transplante , Ovulação/efeitos dos fármacos , Fenótipo , Reprodução/efeitos dos fármacos , Espermatozoides/efeitos dos fármacos , Esfingosina/análogos & derivados , Esfingosina/farmacologia , Esfingosina/uso terapêutico , Útero/efeitos dos fármacos , Útero/patologia , Proteína X Associada a bcl-2/deficiência , Proteína X Associada a bcl-2/metabolismo
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