Lysosomal membrane protein Sidt2 knockout induces apoptosis of human hepatocytes in vitro independent of the autophagy-lysosomal pathway / 南方医科大学学报

OBJECTIVE@#To explore the regulatory mechanism of human hepatocyte apoptosis induced by lysosomal membrane protein Sidt2 knockout.@*METHODS@#The Sidt2 knockout (Sidt2-/-) cell model was constructed in human hepatocyte HL7702 cells using Crispr-Cas9 technology.The protein levels of Sidt2 and key autophagy proteins LC3-II/I and P62 in the cell model were detected using Western blotting, and the formation of autophagosomes was observed with MDC staining.EdU incorporation assay and flow cytometry were performed to observe the effect of Sidt2 knockout on cell proliferation and apoptosis.The effect of chloroquine at the saturating concentration on autophagic flux, proliferation and apoptosis of Sidt2 knockout cells were observed.@*RESULTS@#Sidt2-/- HL7702 cells were successfully constructed.Sidt2 knockout significantly inhibited the proliferation and increased apoptosis of the cells, causing also increased protein expressions of LC3-II/I and P62(P < 0.05) and increased number of autophagosomes.Autophagy of the cells reached a saturated state following treatment with 50 μmol/L chloroquine, and at this concentration, chloroquine significantly increased the expressions of LC3B and P62 in Sidt2-/- HL7702 cells.@*CONCLUSION@#Sidt2 gene knockout causes dysregulation of the autophagy pathway and induces apoptosis of HL7702 cells, and the latter effect is not mediated by inhibiting the autophagy-lysosomal pathway.

The new target of Rapamycin: lysosomal calcium channel TRPML1 / 生理学报

Rapamycin (Rap) is an immunosuppressant, which is mainly used in the anti-rejection of organ transplantation. Meanwhile, it also shows great potential in the fields of anticancer, neuroprotection and anti-aging. Rap can inhibit the activity of mammalian target of Rap (mTOR). It activates the transcription factor EB (TFEB) to up-regulate lysosomal function and eliminates the inhibitory effect of mTOR on ULK1 (unc-51 like autophagy activating kinase 1) to promote autophagy. Recent research showed that Rap can directly activate the lysosomal cation channel TRPML1 in an mTOR-independent manner. TRPML1 activation releases lysosomal calcium. Calcineurin functions as the sensor of the lysosomal calcium signal and activates TFEB, thus promoting lysosome function and autophagy. This finding has greatly broadened and deepened our understanding of the pharmacological roles of Rap. In this review, we briefly introduce the canonical Rap-mTOR-ULK1/TFEB signaling pathway, and then discuss the discovery of TRPML1 as a new target of Rap and the pharmacological potential of this novel Rap-TRPML1-Calcineurin-TFEB pathway.

Regulation of FN1 degradation by the p62/SQSTM1-dependent autophagy-lysosome pathway in HNSCC / 国际口腔科学杂志·英文版

Epithelial-mesenchymal transition (EMT) is involved in both physiological and pathological processes. EMT plays an essential role in the invasion, migration and metastasis of tumours. Autophagy has been shown to regulate EMT in a variety of cancers but not in head and neck squamous cell carcinoma (HNSCC). Herein, we investigated whether autophagy also regulates EMT in HNSCC. Analyses of clinical data from three public databases revealed that higher expression of fibronectin-1 (FN1) correlated with poorer prognosis and higher tumour pathological grade in HNSCC. Data from SCC-25 cells demonstrated that rapamycin and Earle's balanced salt solution (EBSS) promoted autophagy, leading to increased FN1 degradation, while 3-methyladenine (3-MA), bafilomycin A1 (Baf A1) and chloroquine (CQ) inhibited autophagy, leading to decreased FN1 degradation. On the other hand, autophagic flux was blocked in BECN1 mutant HNSCC Cal-27 cells, and rapamycin did not promote autophagy in Cal-27 cells; also in addition, FN1 degradation was inhibited. Further, we identified FN1 degradation through the lysosome-dependent degradation pathway using the proteasome inhibitor MG132. Data from immunoprecipitation assays also showed that p62/SQSTM1 participated as an autophagy adapter in the autophagy-lysosome pathway of FN1 degradation. Finally, data from immunoprecipitation assays demonstrated that the interaction between p62 and FN1 was abolished in p62 mutant MCF-7 and A2780 cell lines. These results indicate that autophagy significantly promotes the degradation of FN1. Collectively, our findings clearly suggest that FN1, as a marker of EMT, has adverse effects on HNSCC and elucidate the autophagy-lysosome degradation mechanism of FN1.

Loss of glucocerebrosidase 1 activity causes lysosomal dysfunction and alpha-synuclein aggregation

Lysosomal dysfunction is a common pathological feature of neurodegenerative diseases. GTP-binding protein type A1 (GBA1) encodes beta-glucocerebrosidase 1 (GCase 1), a lysosomal hydrolase. Homozygous mutations in GBA1 cause Gaucher disease, the most common lysosomal storage disease, while heterozygous mutations are strong risk factors for Parkinson's disease. However, whether loss of GCase 1 activity is sufficient for lysosomal dysfunction has not been clearly determined. Here, we generated human neuroblastoma cell lines with nonsense mutations in the GBA1 gene using zinc-finger nucleases. Depending on the site of mutation, GCase 1 activity was lost or maintained. The cell line with GCase 1 deficiency showed indications of lysosomal dysfunction, such as accumulation of lysosomal substrates, reduced dextran degradation and accumulation of enlarged vacuolar structures. In contrast, the cell line with C-terminal truncation of GCase 1 but with intact GCase 1 activity showed normal lysosomal function. When alpha-synuclein was overexpressed, accumulation and secretion of insoluble aggregates increased in cells with GCase 1 deficiency but did not change in mutant cells with normal GCase 1 activity. These results demonstrate that loss of GCase 1 activity is sufficient to cause lysosomal dysfunction and accumulation of alpha-synuclein aggregates.

Degradation of misfolded proteins in neurodegenerative diseases: therapeutic targets and strategies

Mammalian cells remove misfolded proteins using various proteolytic systems, including the ubiquitin (Ub)-proteasome system (UPS), chaperone mediated autophagy (CMA) and macroautophagy. The majority of misfolded proteins are degraded by the UPS, in which Ub-conjugated substrates are deubiquitinated, unfolded and cleaved into small peptides when passing through the narrow chamber of the proteasome. The substrates that expose a specific degradation signal, the KFERQ sequence motif, can be delivered to and degraded in lysosomes via the CMA. Aggregation-prone substrates resistant to both the UPS and the CMA can be degraded by macroautophagy, in which cargoes are segregated into autophagosomes before degradation by lysosomal hydrolases. Although most misfolded and aggregated proteins in the human proteome can be degraded by cellular protein quality control, some native and mutant proteins prone to aggregation into beta-sheet-enriched oligomers are resistant to all known proteolytic pathways and can thus grow into inclusion bodies or extracellular plaques. The accumulation of protease-resistant misfolded and aggregated proteins is a common mechanism underlying protein misfolding disorders, including neurodegenerative diseases such as Huntington's disease (HD), Alzheimer's disease (AD), Parkinson's disease (PD), prion diseases and Amyotrophic Lateral Sclerosis (ALS). In this review, we provide an overview of the proteolytic pathways in neurons, with an emphasis on the UPS, CMA and macroautophagy, and discuss the role of protein quality control in the degradation of pathogenic proteins in neurodegenerative diseases. Additionally, we examine existing putative therapeutic strategies to efficiently remove cytotoxic proteins from degenerating neurons.

Escala da Satisfação com a decisão em saúde: instrumento adaptado e validado para língua portuguesa / Decision making satisfaction in health scale: instrument adapted and validated to portuguese / Escala de la satisfacción con las decisiones en la salud: instrumento adaptado y validado para el idioma portugués

A tomada de decisão é uma área de investigação na saúde que tem vindo a ganhar importância quer pelos modelos de parceria de cuidados que dão protagonismo ao paciente e família, quer pela preocupação crescente com a qualidade e satisfação do cliente com os cuidados disponibilizados. Assim, propusemo-nos efetuar a adaptação transcultural e avaliar as propriedades psicométricas da versão portuguesa da "The Satisfaction with Decision Scale" de Holmes-Rovner (1996), que visa avaliar a satisfação com as decisões tomadas em saúde. A amostra foi constituída por 521 estudantes da Escola Superior de Enfermagem do Porto. Os resultados obtidos nos testes de fiabilidade revelam uma boa consistência interna para o total dos itens (Alpha Cronbach = 0,88). O estudo psicométrico permite-nos afirmar que a versão em Português da "The Satisfaction with Decision Scale", que denominamos "Escala da Satisfação com a Decisão em Saúde", é um instrumento fidedigno e válido.

Decision making is an area of health research that has gained importance both for the partnership models of care that give prominence to the patient and family, either by growing concern about quality and customer satisfaction with the care provided. So we decided to make the cultural adaptation and to evaluate the psychometric properties of the Portuguese version "The Satisfaction with Decision Scale" de Holmes-Rovner (1996), which aims to assess satisfaction with the decisions taken in health. The sample consisted of 521 nursing students the School of Nursing of Porto. The results of reliability tests show good internal consistency for the total items (Alpha Cronbach = 0.88). The psychometric study allows us to state that the Portuguese version of "The Satisfaction with Decision Scale", we call "Escala da Satisfação com a Decisão em Saúde", is an instrument comparable with the original in terms of validity and reliability.

La toma de decisiones es un área de investigación en salud que ha ganado importancia tanto por los modelos de atención dirigida al paciente y su familia, como por la creciente preocupación por la calidad y satisfacción del cliente con la atención recibida. Por esta razón decidimos hacer la adaptación transcultural y evaluar las propiedades psicométricas de la versión portuguesa "The Satisfaction with Decision Scale" de Holmes-Rovner (1996), que tiene como objetivo evaluar la satisfacción con las decisiones adoptadas en materia de salud. La muestra consta de 521 estudiantes de la Escuela de Enfermería del Porto. Los resultados de las pruebas de fiabilidad muestran una buena consistencia interna para la escala total (Alpha Cronbach = 0,88). El estudio psicométrico nos permite afirmar que la versión en portugués de "The Satisfaction with Decision Scale", que nosotros llamamos "Escala da Satisfação com a Decisão em Saúde", es válida.

The adaptation problems of patients undergoing hemodialysis: socio-economic and clinical aspects / Problemas adaptativos de pacientes em hemodiálise: aspectos socioeconômicos e clínicos / Problemas adaptativos de pacientes en hemodiálisis: aspectos socioeconómicos y clínicos

OBJECTIVES: to identify adaptation problems under Roy's Model in patients undergoing hemodialysis and to correlate them with the socioeconomic and clinical aspects. METHOD: a transversal study, undertaken using a questionnaire. The sample was made up of 178 individuals. The Chi-squared and Mann-Whitney U tests were undertaken. RESULTS: the adaptation problems and the socioeconomic and clinical aspects which presented statistical associations were: Hyperkalemia and age; Edema and income; Impairment of a primary sense: touch and income; Role failure and age; Sexual dysfunction and marital status and sex; Impairment of a primary sense: vision and years of education; Intolerance to activity and years of education; Chronic pain and sex and years of education; Impaired skin integrity and age: Hypocalcemia and access; Potential for injury and age and years of education; Nutrition below the organism's requirements and age; Impairment of a primary sense: hearing and sex and kinetic evaluation of urea; Mobility in gait and/or coordination restricted, and months of hemodialysis; and, Loss of ability for self-care, and months of hemodialysis and months of illness. CONCLUSION: adaptation problems in the clientele undergoing hemodialysis can be influenced by socioeconomic/clinical data. These findings contribute to the development of the profession, fostering the nurse's reflection regarding the care. .

OBJETIVOS: identificar os problemas adaptativos de Roy em pacientes submetidos a hemodiálise e correlacioná-los aos aspectos socioeconômicos e clínicos. MÉTODO: estudo transversal, realizado através de um formulário. A amostra foi de 178 indivíduos. Efetuaram-se os testes qui-quadrado e U de Mann-Whitney. RESULTADOS: os problemas adaptativos e os aspectos socioeconômicos e clínicos que apresentaram associações estatísticas foram: hipercalemia e idade; edema e renda; deficiência de um sentido primário: tátil e renda; falha no papel e idade; disfunção sexual e estado civil e sexo; deficiência de um sentido primário: visão e anos de estudo; intolerância à atividade e anos de estudo; dor crônica e sexo e anos de estudo; integridade da pele prejudicada e idade; hipocalcemia e acesso; potencial para lesão e idade e anos de estudo; nutrição menor que as necessidades do organismo e idade; deficiência de um sentido primário: audição e sexo e avaliação cinética da ureia; mobilidade andar e/ou coordenação restritas e meses de hemodiálise e perda de habilidade de autocuidado e meses de hemodiálise e meses de doença. CONCLUSÃO: problemas adaptativos da clientela hemodialítica podem sofrer influências de dados socioeconômicos/clínicos. Tais achados contribuem para o desenvolvimento da profissão, proporcionando reflexão por parte do enfermeiro acerca do cuidado. .

OBJETIVOS: identificar los problemas adaptativos de Roy en pacientes sometidos a hemodiálisis y correlacionarlos a los aspectos socioeconómicos y clínicos. MÉTODO: estudio transversal, realizado a través de un formulario. La muestra fue de 178 individuos. Se efectuaron las pruebas Chi-cuadrado y U de Mann-Whitney. RESULTADOS: los problemas adaptativos y los aspectos socioeconómicos y clínicos que presentaron asociaciones estadísticas fueron: Hiperkalemia y edad; Edema y renta; Deficiencia de un sentido primario: táctil y renta; Fracaso en el papel y edad; Disfunción sexual y estado civil y sexo; Deficiencia de un sentido primario: visión y años de estudio; Intolerancia a la actividad y años de estudio; Dolor crónico y sexo y años de estudio; Integridad de la piel perjudicada y edad; Hipocalcemia y acceso; Potencial para lesión y edad y años de estudio; Nutrición menor que las necesidades del organismo y edad; Deficiencia de un sentido primario: audición y sexo y evaluación cinética de la urea; Movilidad andar y/o coordinación restringidas y meses de hemodiálisis; y, Pérdida de habilidad de autocuidado y meses de hemodiálisis y meses de enfermedad. CONCLUSIÓN: los problemas adaptativos de la clientela hemodialítica pueden sufrir influencias de datos socioeconómicos/clínicos. Esos hallazgos contribuyen para el desarrollo de la profesión, permitiendo la reflexión del enfermero acerca del cuidado. .

Neck circumference as a potential marker of metabolic syndrome among college students / Circunferência do pescoço como possível marcador para síndrome metabólica em universitários / La circunferencia del cuello como posible indicador del síndrome metabólico en universitarios

OBJECTIVE: to relate neck circumference with metabolic syndrome and its criteria among college students. METHOD: cross-sectional study conducted with 702 college students in Fortaleza, CE, Brazil from September 2010 to June 2011. Socio-demographic data, waist circumference and neck circumference were collected together with blood pressure, fasting blood sugar, triglyceride levels, and HDL-C. RESULTS: 1.7% of the studied sample presented metabolic syndrome. Of these, 58.3% presented altered neck circumference (p<0.006). As neck circumference decreases, pressure levels improve (p<0.001). Additionally, college students with high fasting blood sugar (p=0.003) and high triglyceride levels (p<0.001) presented higher values of neck circumference. CONCLUSION: neck circumference is a potential predictive marker in the detection of metabolic syndrome and its components among college students. .

OBJETIVO: relacionar a circunferência do pescoço com a síndrome metabólica e seus critérios em universitários. MÉTODO: estudo transversal, realizado com 702 universitários de Fortaleza, CE, Brasil, no período de setembro de 2010 a junho de 2011. Coletaram-se dados sociodemográficos, circunferência da cintura, circunferência do pescoço, níveis de pressão arterial e glicemia plasmática de jejum, triglicerídeos e lipoproteína de alta densidade. RESULTADOS: 1,7% da amostra investigada tinha a síndrome metabólica. Desses, 58,3% apresentaram circunferência do pescoço alterada (p<0,006). Na medida em que decresce a circunferência do pescoço, os valores pressóricos dos universitários melhoram (p<0,001). Também, observou-se que universitários com valores de glicemia de jejum plasmática (p=0,003) e triglicerídeos (p<0,001) elevados apresentaram maiores valores de circunferência do pescoço. CONCLUSÃO: a circunferência do pescoço mostrou-se um possível marcador preditivo para detecção da síndrome metabólica e seus componentes em universitários. .

OBJETIVO: relacionar la circunferencia del cuello con el síndrome metabólico y sus criterios en universitarios. MÉTODO: estudio transversal realizado con 702 universitarios de Fortaleza-CE, Brasil, en el período de septiembre de 2010 a junio de 2011. Se recolectaron datos sociodemográficos, circunferencia de la cintura, circunferencia del cuello, niveles de presión arterial y glucemia plasmática de ayuno, triglicéridos y HDL-C. RESULTADOS: 1,7% de la muestra investigada tenían el síndrome metabólico. De estos, 58,3% presentaron circunferencia del cuello alterada (p<0,006). A medida que decrece la circunferencia del cuello mejoran los valores de la presión de los universitarios (p<0,001). También, se observó que los universitarios con valores de glucemia de ayuno plasmática (p=0,003) y triglicéridos (p<0,001) elevados presentaron mayores valores de circunferencia del cuello. CONCLUSIÓN: la circunferencia del cuello se mostró un posible indicador de predicción para la detección del síndrome metabólico y sus componentes, en universitarios. .

Intracellular protein degradation: from a vague idea through the lysosome and the ubiquitin-proteasome system and onto human diseases and drug targeting / La degradación intracelular de proteínas: Desde una vaga idea, a través del lisosoma y el sistema ubiquitina-proteosoma a las enfermedades humanas y el blanco de las drogas

Between the 1950s and 1980s, scientists were focusing mostly on how the genetic code is transcribed to RNA and translated to proteins, but how proteins are degraded has remained a neglected research area. With the discovery of the lysosome by Christian de Duve it was assumed that cellular proteins are degraded within this organelle. Yet, several independent lines of experimental evidence strongly suggested that intracellular proteolysis is largely non-lysosomal, but the mechanisms involved remained obscure. The discovery of the ubiquitin-proteasome system resolved the enigma. We now recognize that degradation of intracellular proteins is involved in regulation of a broad array of cellular processes, such as cell cycle and division, regulation of transcription factors, and assurance of the cellular quality control. Not surprisingly, aberrations in the system have been implicated in the pathogenesis of human disease, such as malignancies and neurodegenerative disorders, which led subsequently to an increasing effort to develop mechanism-based drugs.

Entre los años 1950 y 1980 los científicos focalizaron sus estudios sobre la forma en que el código genético es transcripto al ARN y traducido a las proteínas, dejando de lado la forma en que éstas se degradan. Con el descubrimiento de los lisosomas por Christian de Duve se asumió que las proteínas se degradaban en el interior de esa organela. Sin embargo, varias líneas de trabajo independientes sugerían fuertemente que la proteólisis intracelular era en su mayor parte no lisosómica, aunque se desconocían sus mecanismos. El descubrimiento del sistema ubiquitina-proteosoma resolvió el enigma. Ahora sabemos que la degradación intracelular de proteínas participa en la regulación de un amplio espectro de procesos celulares como la división y el ciclo celular, la regulación de los factores de transcripción y el control de la calidad celular. No es sorpresa entonces que las aberraciones del sistema estén relacionadas con la patogénesis de enfermedades humanas como tumores y desórdenes neurodegenerativos, lo que llevó luego a un esfuerzo para desarrollar drogas basadas en este mecanismo.

Análisis morfométrico de lisosomas: marcadores de transformación celular del epitelio mamario / Morphometric analysis of lysosomes: markers of cellular transformation of the mammary epithelium

ANTECEDENTES: Transformación celular es el mecanismo resultante de la potente acción generada por onco-genes transformantes sobre una célula normal, los cuales con la consiguiente expresión de oncoproteínas determinan drásticos cambios tanto en la morfología como en los volúmenes de los componentes celulares, generando una célula con diferente funcionalidad. OBJETIVO: Precisar las modificaciones que caracterizan al mecanismo transformante en células de epitelio mamario transfectado con el oncogén ras (HC1 Iras) en comparación con su tipo celular normal (HC11GM). MÉTODO: Se estudió con microscopía electrónica de transmisión aplicando técnicas morfométricas a estos tipos celulares con énfasis en los lisosomas, cuantificando variaciones del organelo responsable de la digestión celular. RESULTADOS: Todos los parámetros lisosomales evaluados en el tipo celular transformado presentan diferencias significativas con respecto a la célula normal. CONCLUSIÓN: Las drásticas modificaciones experimentadas por los lisosomas se reflejan en la adquisición de nuevas funcionalidades en la célula transformada.

BACKGROUND: Cellular transformation is the result mechanism of powerful action generated by transforming oncogene over a normal cell, which with the subsequent oncoprotein expression leads to drastic changes in morphology as well as in cell components volumes, generating a cell with a different function. OBJECTIVE: To specify the modifications that characterizes the transforming mechanism in mammary epithelial cells transfected with the ras oncogene comparing them with its normal cell type. METHOD: Transmission electronic microscopy using morphometric techniques was applied to this cell types, emphasizing lysosomes variations, trying to clarify its role in each cell type metabolism. RESULTS: Everyone lysosomal parameters examined in transformed cell type present significant differences regarding to the normal cells. CONCLUSION: The drastic changes in lysosomes reflected in the acquisition of new energy requirements and metabolism in the transformed cell.

Heat shock protein 70 alters the endosome-lysosomal localization of huntingtin

Huntington's disease is caused by CAG trinucleotide expansions in the gene encoding huntingtin. N- terminal fragments of huntingtin with polyglutamine produce aggregates in the endosome-lysosomal system, where proteolytic fragments of huntingtin is generated. Heat shock protein 70 (HSP70) prevents the formation of protein aggregates, but the effect of HSP70 on the huntingtin in the endosome-lysosomal system is unknown. This study was to determine whether HSP70 alters the distribution of huntingtin in endosome-lysosomal system. HSP70 expressing stable cells (NIH/3T3 or cerebral hybrid cell line A1) were generated, and mutant [(CAG)100] huntingtin was transiently overexpressed. Analysis of subcellular distribution by immnuocytochemistry or proteolysis cleavage by Western blotting was performed. 18 CAG repeat wild type [WT; (CAG)18] huntingtin was used as a control. Cells with huntingtin showed patterns of endosome- lysosomal accumulation, from a 'dispersed vacuole (DV)' type into a coalescent 'perinuclear vacuole (PV)' type over time. In WT huntingtin, HSP70 increased the cells with the PV types that enhanced the proteolytic cleavage of huntingtin. However, HSP70 reduced cells of the DV and PV types expressing mutant huntingtin, that result in less proteolysis than that of control. In addition, intranuclear inclusions were formed only in mutant cells, which was not affected by HSP70. These results suggest that HSP70 alters the distribution of huntingtin in the endosome-lysosomal system, and that this contributes to huntingtin proteolysis.

Extracellular breakdown of collagen by mice decidual cells. A cytochemical and ultrastructural study

The interaction of antimesometrial decidual cells and collagen fibrils was studied by light microscopy and ultrastructural cytochemistry in fed and acutely fasted mice on days 9-11 of pregnancy. Fibrillar elements in the extracellular space consisted of collagen fibrils and filamentous aggregates (disintegrating collagen fibrils). Intracellular vacuoles exhibited typical collagen immersed in electron-translucent material (clear vacuoles) and faint cross-banded collagen immersed in electron-opaque material (dark vacuoles). Fibrillar elements showed extracellular acid phosphatase activity which was stronger in the region of mature decidua than in predecidual cells region in all animals; it was conspicuous in mature decidua of fasted animals. Intracellular acid phosphatase activity was observed in dark vacuoles and lysosomes, and was absent in clear vacuoles in all cells studied. Since acid phosphatase activity reflects the presence of lysosomal hydrolases in general, the results indicate that breakdown of extracellular collagen occurs by release of lysosomal enzymes by decidual cells and also by internalization of collagen for intracellular degradation in fed and fasted mice. Collagen breakdown may be part of the process of tissue remodeling in mature and predecidual regions, however, in mature decidua, collagen breakdown is enhanced and may therefore contribute to nutrition of the fetus, specially in acutely fasted mice.

Oxidative and non-oxidative activation of murine peritoneal macrophages by histone H1.

The present study aimed at assessing the role of histone H1 in activating macrophages. Histone H1, injected intraperitoneally at a dose of 1 mg/kg body weight as multiple regimens weekly, significantly increased the number of peritoneal macrophages post 21 days of injection. The oxidative and non-oxidative activation of peritoneal macrophages by histone H1 was assessed. For the assessment of oxidative activation the levels of superoxide radical and nitric oxide radical were assessed. The oxidative activation was evident from release of significantly high levels of superoxide and nitric oxide radicals liberated by macrophages of animals treated with histone H1 (P < 0.001) than in untreated animals. In addition, the higher activities of superoxide dismutase indicated protective effect of histone H1, to keep away the macrophages from noxious effects of superoxide. The catalase activity was decreased significantly in macrophages of histone H1 treated animals. The levels of reduced glutathione were significantly (P < 0.001) lowered in treated animals, whereas the levels of lipid peroxides generated were non-significant. The non-oxidative activation was assessed from the activities of lysosomal enzymes released and also from cytolysis of NO-insensitive L929 cells. The activities of lysosomal enzymes-acid phosphatase and beta-glucuronidase released were significantly high in treated animals than in untreated animals (P < 0.001). Histone H1 stimulated the cytolysis of macrophages in L929 cells than in untreated animals. These results suggest that histone H1 stimulates macrophages by oxidative and non-oxidative mechanisms, which favor its future therapeutic prospects.

Biochemical Characteristics of a Korean Patient with Mucolipidosis III (Pseudo-Hurler Polydystrophy)

We performed a biochemical study on the patient with mucolipidosis III (ML-III, pseudo-Hurler polydystrophy) in Korea. Confluent fibroblasts from the patient and from normal controls were cultured for 4, 12, 24, 48, and 72 hr, respectively. Lysosomal enzyme activities in culture media after different incubation times and in plasma, leukocytes, and fibroblasts were determined. Most of the leukocyte lysosomal enzymes were within normal limits or slightly lowered; however, plasma lysosomal enzyme activities such as those of hexosaminidase and arylsulfatase A were markedly increased. Numerous phase-dense inclusions were present in the cytoplasm of cultured fibroblasts. Lysosomal enzyme activities of fibroblasts were markedly decreased except for beta-glucosidase. The rates of increase of the lysosomal enzyme activities with incubation time were greater in the culture medium of the patient than in normal control, whereas no difference in the beta-glucosidase activity of the culture media of the patient and the control was found. This study describes the first case of ML-III in Korea, with its typical biochemical characteristics, i.e., a problem with targeting and transporting of lysosomal enzymes which results in a marked increase in plasma lysosomal enzyme activities and a high ratio of extracellular to intracellular lysosomal enzyme activities in cultured fibroblasts.

Effect of metal ions on the stability of metallothionein in the degradation by cellular fractions in vitro

Metallothioneins (MT), small molecular weight metal binding proteins are known to play an important protective role against heavy metal toxicity, either as antioxidants or pre-oxidants. However, the mode of metabolic fate of MTs in various metal complexes is not clearly understood. This study was carried out to better understand the mode of selective turnover rate of various form of MT in complexes with different metals. The degradation of in vitro translated mouse 35S-cysteine-MT was examined in lysosomal or cytosolic fractions from mouse liver by gel electrophoresis and autoradiography. Overnight incubations of MT showed extensive proteolysis in the lysosomal fraction but not in cytosolic fractions. However, Cu2+-MT was found to be stable under the same experimental condition. In contrast, Zn did not interfere with MT degradation. These results suggest that lysosomes are chiefly responsible for MT removal and appears to be selective on the metals involved in the MT complex. In vitro, translated, radiolabeled MT provides a suitable substrate for investigating the characteristics of MT degradation.

The effects of castration on the dense-core vesicles and lysosomes of pinelacoytes in male adult mice: a quantitative study

The dense-core vesicles and lysosomes of the adult mice pinealocytes has been studied during normal and experimental (castrated) conditions. Twelve male animals were studied and divided into two groups of six animals: a control group and a castrated one. In all the specimens the dense-core vesicles and lysosomes were counted in a total area of 2,764.80 µm2 of pineal tissue. In adult mice the pineal gland shows dense clusters of light and dark pinealocytes in a distinct rosette-like arrangement. The perinuclear region and cytoplasmic processes of these cells have a moderate distribution of lysosomes and dense-core vesicles. The castrated animals showed a decrease in the number of lysosomes and an increase in the number of dense-core vesicles. Thus, it appears from the present results that the testicular androgens play an inhibitory function on the secretory activity of pinealocytes.

Degradation of phagosomes and diurnal changes of lysosomes in rabbit retinal pigment epithelium

Diurnal changes of lysosomes including ultrastructural changes of phagosomes and acid phosphatase reactions in phagosomes, as well as diurnal biochemical changes in cathepsin D activity, were studied in the retinal pigment epithelium (RPE) of the rabbit. The rabbit was maintained on a natural light-dark cycle over seven days in fall and was sacrificed at various times during the day and night. The number of lysosomes or phagosomes in the RPE was the highest at 1.5 hours after exposure to sunlight (8:00 AM), and thereafter decreased with time. Three types of phagosomes were observed and acid phosphatase reactions were different in each type of phagosome; the fresh phagosomes were negative or positive, lamellar bodies positive, and dense bodies partially positive. The biochemical activity of cathepsin D was the highest at 8:00 AM, and this was consistent with the time of peak in phagocytic activity in the RPE. This report shows that phagocytic activity in the RPE occurred in the early stage after exposure to sunlight, and that fresh phagosomes were sequentially degraded to lamellar or dense bodies. Cathepsin D activity also increased, and this was consistent with the phagocytic activity in the RPE.

El sistema lisosomal en los mecanismos hormonales: revisión / Lysosomal system in hormonal mechanisms: review

Los lisosomas no deben considerarse sólo orgánulos que participan en la lisis de diferentes moléculas en proceso de digestión o defensa celular, ya que participan en diversos procesos de metabolismo celular, incluyendo los regulados hormonales. La actividad lisosomal se ve alterada minutos después de la administración de hormonas tanto esteroides como peptídicas incluyendo efectos como: labilización de membranas, cambio en la estructura química de las hidrolasas (latencia estructural) y migración perinuclear de lisosomas. Estas alteraciones demuestran que la actividad lisosomal es hormino-dependiente, y que hidrolasas como fosfatasa ácida pueden esta actuando de alguna manera a nivel de des-represión génica. Por otro lado, los lisosomas pueden propagar efectos hormonales desde la superficie de las células blanco hasta el núcleo. Es muy probable que ésta propagación se efectúe por medio de poblaciones especializadas de lisosomas que bajo el efecto hormonal migran a la región perinuclear. Se ha demostrado que ciertas substancias naturales y sintéticas que estabilizan membranas pueden bloquear esos eventos de distinto grado, de tal manera, que estos restablecen la labilización lisosomal y por consiguiente impiden la liberación enzimática. De una u otra forma, por lo anteriormente descrito, el sistema lisosomal participa en los mecanismos de comunicación autocrina, paracrina y endocrina