Novel functional roles of caspase-related genes in the regulation of apoptosis and autophagy

Caspases, a family of cysteine proteases, cleave substrates and play significant roles in apoptosis, autophagy, and development. Recently, our group identified 72 genes that interact with Death Caspase-1 (DCP-1) proteins in Drosophila by genetic screening of 15,000 EP lines. However, the cellular functions and molecular mechanisms of the screened genes, such as their involvement in apoptosis and autophagy, are poorly understood in mammalian cells. In order to study the functional characterizations of the genes in human cells, we investigated 16 full-length human genes in mammalian expression vectors and tested their effects on apoptosis and autophagy in human cell lines. Our studies revealed that ALFY, BIRC4, and TAK1 induced autophagy, while SEC61A2, N-PAC, BIRC4, WIPI1, and FALZ increased apoptotic cell death. BIRC4 was involved in both autophagy and apoptosis. Western blot analysis and luciferase reporter activity indicated that ALFY, BIRC4, PDGFA, and TAK1 act in a p53-dependent manner, whereas CPSF1, SEC61A2, N-PAC, and WIPI1 appear to be p53-independent. Overexpression of BIRC4 and TAK1 caused upregulation of p53 and accumulation of its target proteins as well as an increase in p53 mRNA levels, suggesting that these genes are involved in p53 transcription and expression of its target genes followed by p53 protein accumulation. In conclusion, apoptosis and/or autophagy mediated by BIRC4 and TAK1 may be regulated by p53 and caspase activity. These novel findings may provide valuable information that will aid in a better understanding of the roles of caspase-related genes in human cell lines and be useful for the process of drug discovery.

Muerte celular programada en protozoarios: el caso de Giardia intestinalis / Programmed cell death in protozoa: Giardia intestinalis’s case

Giardia intestinalis es considerado uno de los eucariotas más antiguos y su poca complejidad representa una valiosa oportunidad para desentrañar los misterios de procesos vitales de eucariotas más complejos. Esta característica única de G. intestinalis y el hecho de que su genoma esté completamente secuenciado y disponible, y que todo su ciclo de vida puede ser reproducido in vitro, hacen de este parásito un modelo ideal para estudiar mecanismos celulares, entre ellos, la muerte celular programada. Desde el punto de vista morfológico y molecular, la apoptosis es uno de los tipos más complejos de muerte celular programada, la cual es un proceso normal durante el desarrollo celular, y tiene un papel esencial en el control de la proliferación celular y en la respuesta a retos inmunológicos o a daños celulares. Recientemente, se ha reportado que en protozoos, entre ellos Giardia, podría ocurrir un tipo de muerte celular programada similar a la apoptosis y los resultados de nuestros laboratorios apoyan esta hipótesis; sin embargo, no se han identificado hasta el momento las moléculas relacionadas con los procesos de apoptosis en estos parásitos. La presente revisión abarca una descripción de la morfología y estructura de las formas de vida de G. intestinalis, de su ciclo biológico, de la parasitosis que causa y de las estrategias quimioterapéuticas para su tratamiento. Asimismo, se hace un repaso de lo que hasta ahora se conoce sobre apoptosis en protozoarios, y específicamente en G. intestinalis, y se describen algunos resultados de nuestro grupo que apoyan la existencia de muerte celular programada en este parásito.

Giardia intestinalis is an early-branching eukaryote and its low complexity represents a valuable opportunity to unravel the mysteries of essential processes in more complex eukaryotes. In addition, the genome of G. intestinalis is completely sequenced and its entire life cycle can be reproduced in vitro. All these characteristics make of Giardia an ideal model for studying cellular mechanisms, such as programmed cell death. Apoptosis is one of the most complex types of programmed cell death and plays an essential role during cell development, cell proliferation and immune response. Recently it has been reported that in Giardia can take place events that resemble apoptosis and although our results support this hypothesis, molecules involved in this process have not yet been identified. This review includes a description of the morphology and structure of G. intestinalis, its life cycle, the disease that causes and the strategies for its treatment. In addition, we review what is known about apoptosis in protozoa, and specifically in G. intestinalis, and describe some results from our group supporting the existence of apoptosis-like programmed cell death in this parasite.

Effect of ascorbic acid combined with arsenic trioxide on apoptosis and differentiation in myelocytic leukemia cell lines / 中国地方病学杂志

Objective To investigate the effects of arsenic trioxide(As2O3)combined with ascorbic acid(AA) on the apoptosis and differentiation of myelocytic leukaemia cells.Methods The acute promyelecytic leukaemia cell lines (NB4 and MR2)and erythroleukemia cell line(KS62)were cultured in vitro.Grouping wasbased on different concentration of As2O3(0,0.1,0.2,0.5,1.0 μmol/L),which WaS used a8 control groups.Then,AA(113.0μmol/)was added into each group.Cell morphologic changes of cell lines NB4,MR2 and K562 were observed under light microscope;The apoptosis symbols [Annexin V(+)/PI(-),Annexin V(+)/PI(+)]and differentiation symbols(CD11b and CD33)were detected by flow cytometry 96 hours later.Results

All-trans retinoic acid sensitizes human medulloblastoma cells Med-3 to anti-Fas antibody mediated apoptosis / 中国免疫学杂志

Objective:It was aimed to highlight the pro apoptotic significance and immunotherapeutic value of the membrane type Fas(mFas)up regulated in all trans retinoic acid(RA)differentiated medulloblastoma cells Med 3.Methods:Med 3 cells were treated by 10 ?mol/L RA for 0,24,48 or 72 h,followed by the supplementation of anti Fas antibody in the final concentration of 25,50,100,200 or 400 ng/ml.The cell morphology ,growth and death pattern(s)were evaluated by multiple approaches.Results:RA could promote cell differentiation and mFas expression but not induce apoptosis.Anti Fas antibody alone had no biological effect on Med 3 cells but when combined with 10 ?mol/L RA,showed pro apoptotic activity in a dose related fashion.The best apoptotic induction could be achieved in the cell population pretreated by RA for 48 h.Conclusion:The RA enhanced apoptotic susceptibility of Med 3 cells is closely associated with mFas up regulation.The chemical activation of Fas suicide system may be a novel regimen for medulloblastomas.

The effects of aminophylline on mRNA expression of interleukin-5, interleukin -3 and granulocyte-macrophage colony-stimulating factor receptors in eosinop hils of asthmatic guinea pigs / 中国药理学通报

Aim To investigate the effect of Aminophyllin e(AM) on expression of Interleukin-5 receptor ?(IL-5R?), IL-3R?, granulocy te- macrophage-colony-stimulating factor receptor ?(GM-CSFR?) and common ? receptor(?cR) in eosinophils(Eos) of BALF in asthmatic guinea pigs, and mech anism of AM promoting Eos apoptosis. Methods 18 guinea pigs wer e divided into three groups randomly, normal control group, asthma group and AM -treated group. Asthma model of guinea pigs was sensitized by ovalbumin. Hypode nse Eos(HEos) and normodense Eos(NEos) were purified from BALF by gradients of p ercoll. Apoptosis was detected by TUNEL. mRNA expression of IL-5R?, IL-3R?, GM-CSFR? and ?cR in Eos were measured by RT-PCR and hybridization.Re sults Apoptosis of HEos and NEos in asthma group(4?2,3?2) were low er than that in normal group(8?2,7?2)(P