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1.
Urologie ; 62(2): 125-131, 2023 Feb.
Artigo em Alemão | MEDLINE | ID: mdl-36690726

RESUMO

BACKGROUND: In many countries, such as France, England, USA, Canada, Australia, and New Zealand, alloplastic material in prolapse surgery has been paused due to the US Food and Drug Administration (FDA) warning, and restricted in other countries like the Netherlands and Sweden. For Europe and thus Germany, the SCENIHR report allows alloplastic material to be used for prolapse repair after recurrence and in other special situations. QUESTION: Which established and innovative prolapse surgeries without alloplastic material are currently available? METHODS: A literature search was carried out on established, guideline-compliant pelvic floor surgeries without alloplastic material as well as innovative new approaches. RESULTS: An established procedure for a defect in the anterior compartment is anterior colporrhaphy, which is associated with a high recurrence rate. The double-layered anterior colporrhaphy is a new approach and so far is associated with an improved 19-month outcome. Apical pelvic organ prolapse can be corrected by sacrouterine ligament fixation and vaginal sacrospinous fixation. New innovative techniques include laparoscopic unilateral pectineal suspension and the use of the semitendinosus tendon autograft to perform pectopexy or sacropexy. However, long-term data are still pending. In case of a posterior vaginal wall prolapse, posterior colporrhaphy is the therapy of choice and is associated with good success rates. CONCLUSION: Well-known surgical procedures with native tissue are experiencing a renaissance and new, innovative surgical approaches with good postoperative results are being developed. However, long-term studies are still necessary.


Assuntos
Prolapso de Órgão Pélvico , Prolapso Uterino , Estados Unidos , Feminino , Humanos , Telas Cirúrgicas , Prolapso de Órgão Pélvico/cirurgia , Prolapso Uterino/cirurgia , Vagina/cirurgia , Procedimentos Cirúrgicos em Ginecologia/métodos
2.
Immunobiology ; 226(2): 152070, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33639524

RESUMO

Signaling via TNF-R1 mediates pleiotropic biological outcomes ranging from inflammation and proliferation to cell death. Previous reports demonstrated that pro-survival signaling emanates from membrane resident TNF-R1 complexes (complex I) while only internalized TNF-R1 complexes are capable for DISC formation (complex II) and thus, apoptosis induction. Internalized TNF-R1 containing endosomes undergo intracellular maturation towards lysosomes, resulting in activation and release of Cathepsin D (CtsD) into the cytoplasm. We recently revealed HSP90 as target for proteolytic cleavage by CtsD, resulting in cell death amplification. In this study, we show that extrinsic cell death activation via TNF or TRAIL results in HSP90ß degradation. Co-incubation of cells with either TNF or TRAIL in combination with the HSP90ß inhibitor KUNB105 but not HSP90α selective inhibition promotes apoptosis induction. In an attempt to reveal further downstream targets of combined TNF-R1 or TRAIL-R1/-R2 activation with HSP90ß inhibition, we identify HIF1α and validate its ligand:inhibitor triggered degradation. Together, these findings suggest that selective inhibition of HSP90 isoforms together with death ligand stimulation may provide novel strategies for therapy of inflammatory diseases or cancer, in future.


Assuntos
Proteínas de Choque Térmico HSP90/imunologia , Subunidade alfa do Fator 1 Induzível por Hipóxia/imunologia , Ligante Indutor de Apoptose Relacionado a TNF/imunologia , Fator de Necrose Tumoral alfa/imunologia , Apoptose , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Células HeLa , Humanos , Proteoma , Células U937
3.
Andrology ; 4(3): 430-41, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-26916383

RESUMO

Sperm chromatin structure and condensation determine accessibility for damage, and hence success of fertilization and development. The aim of this study was to reveal characteristic spectral features coinciding with abnormal sperm chromatin packing (i.e., DNA-protein interactions) and decreased fertility, using Fourier transform infrared spectroscopy. Chromatin structure in spermatozoa obtained from different stallions was investigated. Furthermore, spermatozoa were exposed to oxidative stress, or treated with thiol-oxidizing and disulfide-reducing agents, to alter chromatin structure and packing. Spectroscopic studies were corroborated with flow cytometric analyses using the DNA-intercalating fluorescent dye acridine orange. Decreased fertility of individuals correlated with increased abnormal sperm morphology and decreased stability toward induced DNA damage. Treatment with the disulfide reducing agent dithiothreitol resulted in increased sperm chromatin decondensation and DNA accessibility, similar as found for less mature epididymal spermatozoa. In situ infrared spectroscopic analysis revealed that characteristic bands arising from the DNA backbone (ν1230, ν1086, ν1051 cm(-1) ) changed in response to induced oxidative damage, water removal, and decondensation. This coincided with changes in the amide-I region (intensity at ν1620 vs. ν1640 cm(-1) ) denoting concomitant changes in protein secondary structure. Reduction in protein disulfide bonds resulted in a decreased value of the asymmetric to symmetric phosphate band intensity (ν1230/ν1086 cm(-1) ), suggesting that this band ratio is sensitive for the degree of chromatin condensation. Moreover, when analyzing spermatozoa from different individuals, it was found that the asymmetric/symmetric phosphate band ratio negatively correlated with the percentage of morphologically abnormal spermatozoa.


Assuntos
Cromatina/química , Dano ao DNA , Fertilidade/fisiologia , Espectroscopia de Infravermelho com Transformada de Fourier , Espermatozoides/química , Animais , Cavalos , Masculino , Estresse Oxidativo/fisiologia , Motilidade dos Espermatozoides/fisiologia
4.
Cell Death Dis ; 4: e929, 2013 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-24263103

RESUMO

The involvement of ceramide in death receptor-mediated apoptosis has been widely examined with most studies focusing on the role of ceramide generated from sphingomyelin hydrolysis. We now analyze the effect of the ceramide acyl chain length by studying tumor necrosis factor α receptor-1 (TNFR1)-mediated apoptosis in a ceramide synthase 2 (CerS2) null mouse, which cannot synthesize very-long acyl chain ceramides. CerS2 null mice were resistant to lipopolysaccharide/galactosamine-mediated fulminant hepatic failure even though TNFα secretion from macrophages was unaffected. Cultured hepatocytes were also insensitive to TNFα-mediated apoptosis. In addition, in both liver and in hepatocytes, caspase activities were not elevated, consistent with inhibition of TNFR1 pro-apoptotic signaling. In contrast, Fas receptor activation resulted in the death of CerS2 null mice. Caspase activation was blocked because of the inability of CerS2 null mice to internalize the TNFR1; whereas Fc-TNFα was internalized to a perinuclear region in hepatocytes from wild-type mice, no internalization was detected in CerS2 null mice. Our results indicate that altering the acyl chain composition of sphingolipids inhibits TNFR1 internalization and inhibits selective pro-apoptotic downstream signaling for apoptosis.


Assuntos
Galactosamina/farmacologia , Lipopolissacarídeos/farmacologia , Fígado/efeitos dos fármacos , Fígado/metabolismo , Receptores Tipo I de Fatores de Necrose Tumoral/metabolismo , Esfingolipídeos/química , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Western Blotting , Hepatócitos/efeitos dos fármacos , Hepatócitos/metabolismo , Camundongos , Camundongos Knockout , Microscopia Confocal , Esfingosina N-Aciltransferase/genética , Esfingosina N-Aciltransferase/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
5.
Physiol Res ; 62(1): 95-105, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23173681

RESUMO

Heterologous expression of Kir channels offers a tool to modulate excitability of neurons which provide insight into Kir channel functions in general. Inwardly-rectifying K+ channels (Kir channels) are potential candidate proteins to hyperpolarize neuronal cell membranes. However, heterologous expression of inwardly-rectifying K+ channels has previously proven to be difficult. This was mainly due to a high toxicity of the respective Kir channel expression. We investigated the putative role of a predominantly glial-expressed, weakly rectifying Kir channel (Kir4.1 channel subunit; KCNJ10) in modulating electrophysiological properties of a motoneuron-like cell culture (NSC-34). Transfection procedures using an EGFP-tagged Kir4.1 protein in this study proved to have no toxic effects on NSC-34 cells. Using whole cell-voltage clamp, a substantial increase of inward rectifying K+ currents as well as hyperpolarization of the cell membrane was observed in Kir4.1-transfected cells. Na+ inward currents, observed in NSC-34 controls, were absent in Kir4.1/EGFP motoneuronal cells. The Kir4.1-transfection did not influence the NaV1.6 sodium channel expression. This study demonstrates the general feasibility of a heterologous expression of a weakly inward-rectifying K+ channel (Kir4.1 subunit) and shows that in vitro overexpression of Kir4.1 shifts electrophysiological properties of neuronal cells to a more glial-like phenotype and may therefore be a candidate tool to dampen excitability of neurons in experimental paradigms.


Assuntos
Neuroblastoma/metabolismo , Canais de Potássio Corretores do Fluxo de Internalização/metabolismo , Neoplasias da Medula Espinal/metabolismo , Animais , Linhagem Celular Tumoral , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Potenciais da Membrana , Camundongos , Canal de Sódio Disparado por Voltagem NAV1.6/metabolismo , Neuroblastoma/genética , Técnicas de Patch-Clamp , Canais de Potássio Corretores do Fluxo de Internalização/genética , Proteínas Recombinantes de Fusão/metabolismo , Neoplasias da Medula Espinal/genética , Transfecção
6.
Scand J Immunol ; 74(2): 126-34, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21410503

RESUMO

γδ T cells play an important role in anti-infective immunity. The major subset of human γδ T cells selectively recognizes phosphorylated bacterial metabolites of the isoprenoid biosynthesis pathway, so-called phosphoantigens. The activation of γδ T cells is modulated by functionally expressed innate immune receptors, notably Toll-like receptor 2 and 3. It was also reported that in vitro expanded γδ T cells respond to muramyl dipeptide (MDP), the minimal peptidoglycan motif activating the nucleotide-binding oligomerization domain containing 2 (NOD2) receptor, although it is unknown whether ex vivo isolated human γδ T cells express functional NOD2. Here, we report that freshly isolated, highly purified peripheral blood γδ T cells express NOD2 mRNA and detectable amounts of NOD2 protein. The biologically active MDP L-D isomer but not the inactive D-D isomer augmented the interferon-γ (IFN-γ) secretion in phosphoantigen-stimulated peripheral blood mononuclear cells. Moreover, a moderate but reproducible and statistically significant increase in IFN-γ secretion was also observed when highly purified peripheral blood γδ T cells were activated by T cell receptor cross-linking in the presence of MDP. Taken together, our results indicate that in addition to the T cell receptor and Toll-like receptors, circulating human γδ T cells express NOD2 as a third class of pattern recognition receptor for sensing bacterial products.


Assuntos
Proteína Adaptadora de Sinalização NOD2/biossíntese , Receptores de Antígenos de Linfócitos T gama-delta/imunologia , Subpopulações de Linfócitos T/imunologia , Acetilmuramil-Alanil-Isoglutamina/imunologia , Células Cultivadas , Humanos , Interferon gama/imunologia , Interferon gama/metabolismo , Leucócitos Mononucleares/imunologia , Receptores de Reconhecimento de Padrão/imunologia , Subpopulações de Linfócitos T/metabolismo
7.
Cell Death Differ ; 11(5): 550-63, 2004 May.
Artigo em Inglês | MEDLINE | ID: mdl-14739942

RESUMO

Acidic noncaspase proteases-like cathepsins have been introduced as novel mediators of apoptosis. A clear role for these proteases and the acidic endolysosomal compartment in apoptotic signalling is not yet defined. To understand the role and significance of noncaspases in promoting and mediating cell death, it is important to determine whether an intersection of these proteases and the caspase pathway exists. We recently identified the endolysosomal aspartate protease cathepsin D (CTSD) as a target for the proapoptotic lipid ceramide. Here, we show that tumor necrosis factor (TNF)-induced CTSD activation depends on functional acid sphingomyelinase (A-SMase) expression. Ectopic expression of CTSD in CTSD-deficient fibroblasts results in an enhanced TNF-mediated apoptotic response. Intracellular colocalization of CTSD with the proapoptotic bcl-2 protein family member Bid in HeLa cells, and the ability of CTSD to cleave directly Bid in vitro as well as the lack of Bid activation in cathepsin-deficient fibroblasts indicate that Bid represents a direct downstream target of CTSD. Costaining of CTSD and Bid with Rab5 suggests that the endosomal compartments are the common 'meeting point'. Caspase-9 and -3 activation also was in part dependent on A-SMase and CTSD expression as revealed in the respective deficiency models. Our results link as novel endosomal intermediates the A-SMase and the acid aspartate protease CTSD to the mitochondrial apoptotic TNF pathway.


Assuntos
Proteínas de Transporte/metabolismo , Caspases/metabolismo , Catepsina D/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Animais , Apoptose/efeitos dos fármacos , Apoptose/fisiologia , Proteína Agonista de Morte Celular de Domínio Interatuante com BH3 , Caspase 3 , Caspase 9 , Células Cultivadas , Ceramidas/metabolismo , Ativação Enzimática/fisiologia , Feminino , Fibroblastos/metabolismo , Células HeLa , Humanos , Camundongos , Camundongos Knockout , Mitocôndrias/metabolismo , Esfingomielina Fosfodiesterase/metabolismo
9.
Regul Pept ; 102(2-3): 93-9, 2001 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-11730981

RESUMO

Nerve growth factor (NGF) has been previously shown to induce exocytosis in rat peritoneal mast cells (RPMCs) in the presence of lyso-phosphatidylserine (lysoPS) by interacting with high-affinity NGF receptors of the TrkA-type. In RPMCs, type D phosphatidylcholine-selective phospholipases (PLDs) have been postulated to be involved in some exocytotic signaling pathways induced by different agonists. The aim of the present study was to assess a putative functional role of PLD for NGF/lysoPS-induced exocytosis in RPMCs. In 1-[14C]palmitoyl-2-lyso-3-phosphatidylcholine-labelled RPMCs, NGF/lysoPS stimulated the formation of diacylglycerol (DAG) and, in the presence of ethanol (1% [v/v]), phosphatidylethanol (PEtOH). These data indicate PLD-activation by NGF/lysoPS in RPMCs. Preincubation of RPMCs for 2 min with ethanol, an inhibitor of PLD-derived DAG-formation, dose-dependently (IC(50): 0.6% [v/v]) and agonist-selectively inhibited the NGF/lysoPS induced release of [3H]serotonin ([3H]5-HT) in [3H]5-HT-loaded RPMCs, confirming the functional importance of PLD-action. Exocytosis and PEtOH-production was potently inhibited by the broad-spectrum serine/threonine kinase inhibitor staurosporine and activated by the protein kinase C(PKC)-activator PMA (phorbol-12-myristate-13-acetate) suggesting a role for PKC as mediator for NGF/lysoPS-induced activation of PLD.


Assuntos
Exocitose/efeitos dos fármacos , Lisofosfolipídeos/farmacologia , Mastócitos/efeitos dos fármacos , Fator de Crescimento Neural/farmacologia , Fosfolipase D/metabolismo , Transdução de Sinais/efeitos dos fármacos , Animais , Diglicerídeos/metabolismo , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Inibidores Enzimáticos/farmacologia , Etanol/farmacologia , Peptídeos e Proteínas de Sinalização Intercelular , Mastócitos/citologia , Mastócitos/enzimologia , Peptídeos , Peritônio/citologia , Peritônio/efeitos dos fármacos , Ésteres de Forbol/farmacologia , Proteína Quinase C/antagonistas & inibidores , Proteína Quinase C/metabolismo , Ratos , Serotonina/metabolismo , Fatores de Tempo , Venenos de Vespas/farmacologia
11.
Oncogene ; 20(31): 4258-69, 2001 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-11464292

RESUMO

The molecular alterations in tumour cells leading to resistance towards apoptosis induced by CD95 and TRAIL-receptors are not fully understood. We report here that the stimulation of the CD95- and TRAIL-resistant human pancreatic adenocarcinoma cell line PancTuI with an agonistic anti-CD95 antibody or TRAIL resulted in activation of protein kinase C and NF-kappaB. Inhibition of protein kinase C by Gö6983 sensitized these cells to apoptotic challenges and strongly diminished activation of NF-kappaB by anti-CD95 and TRAIL. Similarly, inhibition of NF-kappaB by MG132 or by transient transfection with a dominant negative mutant of IkappaBalpha restored the responsiveness of PancTuI cells to both death ligands. In the CD95 and TRAIL-sensitive cell line Colo357 the induction of protein kinase C and NF-kappaB following activation of CD95 and TRAIL-R was very moderate compared with PancTuI cells. However, pre-incubation of these cells with PMA strongly reduced their apoptotic response to anti-CD95 and TRAIL. Taken together, we show that activation of protein kinase C operates directly in a death receptor-dependent manner in PancTuI cells and protect pancreatic tumour cells from anti-CD95 and TRAIL-mediated apoptosis by preventing the loss DeltaPsim and Cytochrome c release as well as by induction of NF-kappaB.


Assuntos
Adenocarcinoma/patologia , Apoptose/fisiologia , Glicoproteínas de Membrana/fisiologia , NF-kappa B/metabolismo , Neoplasias Pancreáticas/patologia , Proteína Quinase C/metabolismo , Fator de Necrose Tumoral alfa/fisiologia , Receptor fas/fisiologia , Adenocarcinoma/enzimologia , Adenocarcinoma/metabolismo , Proteínas Reguladoras de Apoptose , Ativação Enzimática , Humanos , Neoplasias Pancreáticas/enzimologia , Neoplasias Pancreáticas/metabolismo , Ligante Indutor de Apoptose Relacionado a TNF , Células Tumorais Cultivadas
12.
Psychiatr Prax ; 28(3): 115-7, 2001 Apr.
Artigo em Alemão | MEDLINE | ID: mdl-11407253

RESUMO

BACKGROUND: Covers two years experience of family visits (FV) as a routine fixture at a psychiatric ward in a General Hospital. PATIENTS AND METHODS: In the course of one year 98 visits took place involving a total of 481 contacts between therapists, patients, and relatives. 269 patients participated up to 10 times in FV. A total of 666 family members participated, the bulk of them partners, mothers and children. Each FV contact is restricted to 20 minutes, but can be repeated as often as desired. An ever recurrent theme is the question family members ask as to the causes of the patients condition and how they can expedite the healing process and ensure compliance. The 269 FV patients do not differ markedly from the other patients concerning age, sex, diagnosis and treatment time. CONCLUSION: FV are experienced by patients and relatives as positiv and enriching. For psychiatric workers an ideal way to learn the psychotherapeutic rudiments.


Assuntos
Cuidadores/psicologia , Terapia Familiar , Transtornos Mentais/terapia , Relações Profissional-Família , Hospitais Gerais , Humanos , Transtornos Mentais/psicologia , Cooperação do Paciente/psicologia , Unidade Hospitalar de Psiquiatria
14.
J Invest Dermatol ; 115(4): 708-13, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10998148

RESUMO

Point mutations in the suprabasal cytokeratins 1 (K1) or 10 (K10) in humans have been shown to be the cause of the congenital ichthyosis epidermolytic hyperkeratosis. Recently, a K10 deficient mouse model was established serving as a model for epidermolytic hyperkeratosis. Homozygotes suffered from severe skin fragility and died shortly after birth. Heterozygotes developed hyperkeratosis with age. To see whether phenotypic abnormalities in the mouse model were associated with changes in skin barrier function and skin water content we studied basal transepidermal water loss and capacity for barrier repair after experimental barrier disruption as well as stratum corneum hydration. Also, we determined the activities of acid and neutral sphingomyelinase key enzymes of the tumor necrosis factor and interleukin-1 signal transduction pathways generating the ceramides most important for epidermal permeability barrier homeostasis. Neonatal homozygotes showed an 8-fold increase in basal transepidermal water loss compared with wild type controls. Adult heterozygotes exhibited delayed barrier repair after experimental barrier disruption. Stratum corneum hydration was reduced in homozygous and heterozygous mice. Acid sphingomyelinase activity, which is localized in the epidermal lamellar bodies and generates ceramides for extracellular lipid lamellae in the stratum corneum permeability barrier, was reduced in homozygous as well as heterozygous animals. Neutral sphingomyelinase activity, which has a different location and generates ceramides involved in cell signaling, was increased. The reduction in acid sphingomyelinase activity may explain the recently described decreased ratio of ceramides to total lipids in K10 deficient mice. In summary, our results demonstrate the crucial role of the keratin filament for permeability barrier function and stratum corneum hydration.


Assuntos
Água Corporal/metabolismo , Permeabilidade da Membrana Celular/fisiologia , Queratinas/deficiência , Pele/citologia , Esfingomielina Fosfodiesterase/metabolismo , Animais , Animais Recém-Nascidos , Modelos Animais de Doenças , Heterozigoto , Homeostase , Homozigoto , Humanos , Hiperceratose Epidermolítica , Camundongos , Pele/enzimologia , Pele/metabolismo
15.
Adv Exp Med Biol ; 477: 305-15, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10849758

RESUMO

We have identified the aspartic protease cathepsin D as a novel intracellular target protein for the lipid second messenger ceramide. Ceramide specifically binds to and induces CTSD proteolytic activity. A-SMase deficient cells derived from Niemann-Pick patients show decreased CTSD activity that was reconstituted by transfection with A-SMase cDNA. Ceramide accumulation in cells derived from A-ceramidase defective Farber patients correlates with enhanced CTSD activity. These findings suggest that A-SMase-derived ceramide targets endolysosomal CTSD.


Assuntos
Catepsina D/metabolismo , Ceramidas/fisiologia , Sistemas do Segundo Mensageiro/fisiologia , Esfingomielina Fosfodiesterase/fisiologia , Amidoidrolases/deficiência , Amidoidrolases/genética , Animais , Apoptose , Catepsina D/deficiência , Catepsina D/genética , Compartimento Celular , Linhagem Celular Transformada , Ceramidases , Ceramidas/farmacologia , Citocinas/fisiologia , DNA Complementar/genética , Ativação Enzimática/efeitos dos fármacos , Fibroblastos/enzimologia , Fibroblastos/patologia , Células HeLa/metabolismo , Humanos , Isoenzimas/deficiência , Isoenzimas/genética , Isoenzimas/metabolismo , Metabolismo dos Lipídeos , Linfócitos/enzimologia , Lisossomos/enzimologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Doenças de Niemann-Pick/enzimologia , Doenças de Niemann-Pick/genética , Doenças de Niemann-Pick/patologia , Proteínas Recombinantes de Fusão/metabolismo , Esfingomielina Fosfodiesterase/deficiência , Esfingomielina Fosfodiesterase/genética , Células Tumorais Cultivadas , Células U937/metabolismo
16.
J Biol Chem ; 275(39): 30344-54, 2000 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-10862608

RESUMO

To investigate signal transduction pathways leading to apoptosis during the early phase of neurogenesis, we employed PCC7-Mz1 cells, which cease to proliferate and begin to differentiate into a stable pattern of neurons, astroglial cells, and fibroblasts upon incubation with retinoic acid (RA). As part of lineage determination, a sizable fraction of RA-treated cultures die by apoptosis. Applying natural long-chain C(16)-ceramides as well as membrane-permeable C(2)/C(6)-ceramide analogs caused apoptosis, whereas the biologically nonactive C(2)-dihydroceramide did not. Treating PCC7-Mz1 stem cells with a neutral sphingomyelinase or with the ceramidase inhibitor N-oleoylethanolamine elevated the endogenous ceramide levels and concomitantly induced apoptosis. Addition of RA caused an increase in ceramide levels within 3-5 h, which reached a maximum (up to 3.5-fold of control) between days 1 and 3 of differentiation. Differentiated PCC7-Mz1 cells did not respond with ceramide formation and apoptosis to RA treatment. The acidic sphingomyelinase contributed only weakly and the neutral Mg(2+)-dependent and Mg(2+)-independent sphingomyelinases not at all to the RA-mediated production of ceramides. However, ceramide increase was sensitive to the ceramide synthase inhibitor fumonisin B(1), suggesting a crucial role for the de novo synthesis pathway. Enzymatic assays revealed that ceramide synthase activity remained unaltered, whereas serine palmitoyltransferase (SPT), a key enzyme in ceramide synthesis, was activated approximately 2.5-fold by RA treatment. Activation of SPT seemed to be mediated via a post-translational mechanism because levels of the mRNAs coding for the two SPT subunits were unaffected. Expression of marker proteins shows that ceramide regulates apoptosis, rather than differentiation, during early neural differentiation.


Assuntos
Apoptose , Ceramidas/biossíntese , Tecido Nervoso/citologia , Aciltransferases/análise , Amidoidrolases/antagonistas & inibidores , Animais , Astrócitos/citologia , Diferenciação Celular , Linhagem Celular , Linhagem da Célula , Ceramidases , Interações Medicamentosas , Endocanabinoides , Etanolaminas/farmacologia , Fibroblastos/citologia , Camundongos , Tecido Nervoso/efeitos dos fármacos , Neurônios/citologia , Ácidos Oleicos , Oxirredutases/análise , Serina C-Palmitoiltransferase , Transdução de Sinais , Esfingomielina Fosfodiesterase/farmacologia , Células-Tronco , Tretinoína/farmacologia
18.
J Clin Invest ; 104(12): 1761-70, 1999 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-10606630

RESUMO

Epidermal TNF expression increases in response to cutaneous permeability barrier disruption and wound healing. TNF signaling is mediated by acid and neutral sphingomyelinases (A- and N-SMase), which generate ceramide, an important regulator of proliferation, differentiation, and apoptosis. In the epidermis, ceramide is known to be an integral part of the extracellular stratum corneum (SC) lipid bilayers that constitute the permeability barrier of the skin. We show here that topical application of TNF after experimental injury to the SC of hairless mice (hr(-/-)) enhances barrier repair. In TNF receptor p55-deficient (TNF-R55-deficient) mice (hr(+/+)), cutaneous barrier repair was delayed compared with wild-type (hr(+/+)) or TNF-R75-deficient (hr(+/+)) animals. After barrier disruption in hairless (hr(-/-)) and wild-type (hr(+/+)), but not in TNF-R55-deficient (hr(+/+)) mice, the enzymatic activities of both A-SMase and N-SMase were significantly enhanced. Stimulation of SMase activities was accompanied by an increase in C(24)-ceramide levels. Most A-SMase activity in hairless mice (hr(-/-)) was found in the outer epidermal cell layers and colocalized in the lamellar bodies with A-SMase and sphingomyelin. Reduction of epidermal A-SMase activity by the inhibitor imipramine resulted in delayed permeability barrier repair after SC injury. Together, these results suggest that TNF-R55 signaling pathways contribute to cutaneous permeability barrier repair through SMase-mediated generation of ceramide.


Assuntos
Antígenos CD/fisiologia , Receptores do Fator de Necrose Tumoral/fisiologia , Pele/metabolismo , Esfingomielina Fosfodiesterase/fisiologia , Animais , Ceramidas/análise , Glucosilceramidase/fisiologia , Imipramina/farmacologia , Masculino , Camundongos , Camundongos Pelados , Camundongos Endogâmicos C57BL , Permeabilidade , Receptores Tipo I de Fatores de Necrose Tumoral , Esfingomielina Fosfodiesterase/antagonistas & inibidores , Esfingomielinas/análise , Fator de Necrose Tumoral alfa/farmacologia
19.
EMBO J ; 18(19): 5252-63, 1999 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-10508159

RESUMO

Ceramide has been recognized as a common intracellular second messenger for various cytokines, growth factors and other stimuli, such as CD95, chemotherapeutic drugs and stress factors. To understand the role of ceramide during apoptosis and other cellular responses, it is critically important to characterize direct targets of ceramide action. In this paper, we show that ceramide specifically binds to and activates the endosomal acidic aspartate protease cathepsin D. Direct interaction of ceramide with cathepsin D results in autocatalytic proteolysis of the 52 kDa pre-pro cathepsin D to form the enzymatically active 48/32 kDa isoforms of cathepsin D. Acid sphingomyelinase (A-SMase)-deficient cells show decreased cathepsin D activity, which could be reconstituted by transfection with A-SMase cDNA. The results of our study identify cathepsin D as the first endosomal ceramide target that colocalizes with and may mediate downstream signaling effects of A-SMase.


Assuntos
Catepsina D/metabolismo , Ceramidas/metabolismo , Esfingomielina Fosfodiesterase/química , Animais , Sequência de Bases , Ceramidas/química , Primers do DNA , Ativação Enzimática , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Ligação Proteica , Processamento Pós-Transcricional do RNA , Especificidade por Substrato
20.
J Biol Chem ; 274(15): 10203-12, 1999 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-10187805

RESUMO

The 55-kDa receptor for tumor necrosis factor (TR55) triggers multiple signaling cascades initiated by adapter proteins like TRADD and FAN. By use of the primary amine monodansylcadaverine (MDC), we addressed the functional role of tumor necrosis factor (TNF) receptor internalization for intracellular signal distribution. We show that MDC does not prevent the interaction of the p55 TNF receptor (TR55) with FAN and TRADD. Furthermore, the activation of plasmamembrane-associated neutral sphingomyelinase activation as well as the stimulation of proline-directed protein kinases were not affected in MDC-treated cells. In contrast, activation of signaling enzymes that are linked to the "death domain" of TR55, like acid sphingomyelinase and c-Jun-N-terminal protein kinase as well as TNF signaling of apoptosis in U937 and L929 cells, are blocked in the presence of MDC. The results of our study suggest a role of TR55 internalization for the activation of select TR55 death domain signaling pathways including those leading to apoptosis.


Assuntos
Antígenos CD/metabolismo , Apoptose , Cadaverina/análogos & derivados , Proteínas Quinases Ativadas por Mitógeno , Receptores do Fator de Necrose Tumoral/metabolismo , Transdução de Sinais , Cadaverina/metabolismo , Proteínas Quinases Dependentes de Cálcio-Calmodulina/metabolismo , Ceramidas/metabolismo , Endocitose , Células HeLa , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Proteínas Quinases JNK Ativadas por Mitógeno , Células Jurkat , Potássio/metabolismo , Proteínas/metabolismo , Receptores Tipo I de Fatores de Necrose Tumoral , Esfingomielina Fosfodiesterase/metabolismo , Fator 1 Associado a Receptor de TNF , Células U937 , Receptor fas/imunologia , Receptor fas/metabolismo
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