Marker Of Apoptotic Cell Death Research Articles

RNA helicase A is essential for normal gastrulation.

RNA helicase A (RHA) is the human homologue of the Drosophila maleless protein, an essential factor for the development of male flies. Recently, it was shown that RHA cooperates with the cAMP-responsive element in mediating the cAMP-dependent transcriptional activation of a number of genes. Due to the participation of cAMP as a second messenger in a number of signaling pathways, we examined the function of RHA during mammalian embryogenesis. To examine the role(s) of RHA in mammalian development, RHA knockout mice were generated by homologous recombination. Homozygosity for the mutant RHA allele led to early embryonic lethality. Histological analysis, combined with terminal deoxynucleotidyltransferase-mediated UTP end labeling (TUNEL) reactions of RHA-null embryos, revealed marked apoptotic cell death specifically in embryonic ectodermal cells during gastrulation. RNA in situ analyses of the expression of HNF-3beta and Brachyury, two molecular markers for gastrulation, showed that RHA-null embryos at days 7.5 and 8.5 expressed both HNF-3beta and Brachyury in a pattern similar to those of pre- and early streak stages of embryos, respectively. These observations indicate that RHA is necessary for early embryonic development and suggest the requirement of RHA for the survival and differentiation of embryonic ectoderm.

Oxidative Stress Induces DNA Fragmentation and Caspase Activation Via the c-Jun NH2-terminal Kinase Pathway in H9c2 Cardiac Muscle Cells

The aim of this study was to test the hypothesis that oxidative stress induces apoptosis in the H9c2 cardiac muscle cell line, and that signaling via mitogen-activated protein kinase (MAPK) pathways is involved. Three forms of oxidative stress were utilized: the superoxide generator menadione; hydrogen peroxide; or simulated ischemia followed by reperfusion. Relatively low concentrations of menadione (10μm) or H2O2(250μm) caused maximal DNA fragmentation and caspase activation, both markers for apoptotic cell death, and preferential activation of the c-Jun NH2-terminal kinase (JNK) and p38 MAPK pathways. In contrast, higher concentrations of menadione or H2O2caused less DNA fragmentation, more necrotic cell death and preferential activation of the extracellular signal-regulated kinase (ERK) pathway. Simulated ischemia alone did not induce DNA fragmentation or caspase activation and activated only the p38 MAPK pathway. However, ischemia plus reperfusion resulted in DNA fragmentation, caspase activation, necrotic cell death and activation of all three MAPK pathways. Selective inhibition of the ERK or p38 MAPK pathways (by PD98059 or SB-203580, respectively) had no effect on the extent of oxidative stress-induced DNA fragmentation or caspase activation. In contrast, inhibition of the JNK pathway by transfection of a dominant negative mutant of JNK markedly reduced the extent of DNA fragmentation and caspase activation induced by oxidative stress. In conclusion, these data suggest that the JNK pathway plays an important role in signaling oxidative stress-induced apoptosis of H9c2 cardiac muscle cells.

Methotrexate induces apoptotic cell death in human keratinocytes.

The mechanism by which low doses of methotrexate act in psoriasis to restore a clinically normal skin is poorly understood. Apoptosis is a programmed cell death activated when cell removal is needed. The purpose of the present work was to examine using an organotypical model of keratinocyte culture, the possibility that low doses of methotrexate can induce apoptosis of keratinocytes. Epidermal explants were cultivated on dead deepidermized dermis under air-exposed conditions. After 10 days, methotrexate (10(-7) M) was added. After a further 5 days, one part of each culture was fixed and submitted to routine histology, DNA nick end labelling (TUNEL) to detect DNA fragmentation (a molecular marker of apoptotic cell death) and immunohistochemical detection of p53 (a protein involved in apoptosis induced by DNA-damaging agents). The other part of each culture was processed for electron microscopy. A significant proportion of keratinocytes (1%) were damaged and exhibited the morphological features of apoptotic cell death. Immunohistochemical overexpression of p53 was detected in the basal layer of the cultures treated with methotrexate. Low doses of methotrexate induce apoptosis. This mode of action could explain the reduction in epidermal hyperplasia during treatment of psoriasis with methotrexate.

Anti-Fas IgG1 antibodies recognizing the same epitope of Fas/APO-1 mediate different biological effects in vitro.

Fas/APO-1 is a cell surface glycoprotein that mediates programmed cell death or apoptosis when cross-linked with agonistic anti-Fas or anti-APO-1 mAb or the endogenous Fas/APO-1 ligand. In this report, we examined the in vitro biological properties of a panel of anti-human Fas mAb of IgG1 subclass (ZB4, VB3, WB3 and CBE). We found that anti-Fas clone VB3 induced marked apoptotic cell death in Fas/APO-1-expressing Jurkat cells, although this cell killing was delayed when compared to the cytolytic effect mediated by the prototypic anti-Fas antibody of IgM subclass (clone CH-11). The ZB4 antibody, on the other hand, efficiently blocked apoptosis induced by CH-11. The WB3 and CBE clones neither induced or inhibited apoptosis. These antibodies were all found to recognize one and the same linear site on the Fas/APO-1 molecule, despite their different biological effects. The ability of these anti-Fas mAb to induce or inhibit apoptosis appeared to correlate with their relative affinity for the Fas/APO-1 molecule. These results provide further evidence for the potential of anti-Fas antibodies of the IgG1 subclass to elicit signals via the Fas/APO-1 molecule.

Gonadotropin suppression of apoptosis in follicle somatic cells.

In each oestrous cycle only a limited number of follicles are selected for ovulation whereas the remaining majority undergo atresia. The earliest and most prominent feature of atresia is the death of granulosa cells. Recent biochemical evidence has demonstrated that granulosa cell death during follicular atresia in swine (Tillyet al., 1992), bovine (Jollyet al., 1994) and rodent (Tillyet al., 1991) ovaries occurs by apoptosis, a process whereby cells die in a controlled manner. A biochemical event considered to be characteristic of apoptotic cell death is the intranucleosomal cleavage of genomic DNA into fragments 180–200 bp in size, which separate into a distinctive ladder-like pattern on agarose gel electrophoresis. Detection of this pattern of oligonucleosomes in DNA provides a marker of apoptotic cell death.

Intracellular Calcium Levels Influence Apoptosis in Mature Sensory Neurons after Trophic Factor Deprivation

Embryonic dorsal root ganglion (DRG) neurons require nerve growth factor (NGF) for survivalin vitro.Withdrawal of NGF results in an apoptotic death in these immature DRG neurons. After time in culture, DRG neurons become progressively less dependent upon NGF for survival. Immature embryonic DRG neurons remain highly dependent upon NGF during their first 14 days in cell culture but by Day 21 the majority lose their NGF dependence for survival. During this period of maturation, the intracellular calcium concentration ([Ca2+]i) progressively increases from the lower levels found in immature DRG neurons to the higher levels that are characteristic of older or mature DRG neurons. By changing the cell culture medium to one with very low calcium, we were able to lower [Ca2+]iin the mature neurons to levels similar to those found in immature neurons. These mature neurons (e.g., E-15 DRG neurons grown for 21 days in culture), normally NGF independent, became highly dependent upon NGF for survival. The onset of DNA fragmentation is a marker of apoptotic cell death. We measured the onset of DNA fragmentation in apoptotic neurons with use of the fluorescent dye, Hoechst, in neurons maintained in either standard calcium medium (1800 mM) or in the low calcium medium (0.35 mM). A higher percentage of neurons with lowered [Ca2+]ishowed initial signs of apoptosis, i.e., DNA condensation, at earlier times after NGF deprivation. This work provides further evidence to support a “set-point” hypothesis regarding the relationship between intracellular calcium concentration and NGF dependence for survival in DRG neurons.

Evidence for atrophy and apoptosis in the ventral prostate of rats given the 5 alpha-reductase inhibitor finasteride.

Castration causes cell loss in the rat ventral prostate through a process called apoptosis. Although 5 alpha-reductase inhibition also causes prostate cell loss, the mechanisms involved have been debated. To investigate this question further, we have evaluated the histological responses of the rat ventral prostate to both castration and 5 alpha-reductase inhibition. Rats were left intact, castrated, or given the selective 5 alpha-reductase inhibitor finasteride. After 4, 9, 14, and 21 days the prostates were excised, the androgen and DNA content determined, and the tissue was subjected to histological and histomorphometric analysis. Finasteride and castration decreased prostate weight at day 21 by 65% and 93%, respectively. Castration decreased DNA content (micrograms per prostate) by a maximum of 88% at 14 days. Finasteride had no significant effect on DNA content after 4 days and decreased DNA content by a maximum of 52% at 14 days. When castrate prostate sections were stained for tissue transglutaminase, a marker of apoptotic cell death, a maximum of 23% of epithelial cells were stained by day 14 with a return to control levels by day 21. Finasteride caused a less intense increase in staining in which 16% of epithelial cells stained for tissue transglutaminase on day 9 with a return to baseline by day 14. When prostate sections were stained for DNA breaks, another marker of cell death, castration, caused a peak of staining on day 4 with 6% of epithelial cells staining and a return to near control levels by day 21. Finasteride-induced staining was less intense with peak staining at day 4 (0.7% of epithelial cells) and a return to control values by day 9. Morphometrics were used to assess the effect of castration and finasteride on prostate duct size and epithelial cell mass. After 4 days of finasteride treatment, the mean ductal mass decreased by 47%, with no significant change thereafter. The mean epithelial cell mass decreased by 15% on day 4 and 60% on day 9, with no further decrease thereafter. Castration caused a more rapid and greater decrease in both morphometric parameters with a 95% reduction in the mass of prostate ducts and a 93% decrease in epithelial cell mass by day 9. We conclude that castration induces a more profound involution of the rat ventral prostate than does 5 alpha-reductase inhibition. Cell loss occurs in both groups, but the degree of cell loss is less with finasteride.(ABSTRACT TRUNCATED AT 400 WORDS)

Evidence for atrophy and apoptosis in the ventral prostate of rats given the 5 alpha-reductase inhibitor finasteride

Castration causes cell loss in the rat ventral prostate through a process called apoptosis. Although 5 alpha-reductase inhibition also causes prostate cell loss, the mechanisms involved have been debated. To investigate this question further, we have evaluated the histological responses of the rat ventral prostate to both castration and 5 alpha-reductase inhibition. Rats were left intact, castrated, or given the selective 5 alpha-reductase inhibitor finasteride. After 4, 9, 14, and 21 days the prostates were excised, the androgen and DNA content determined, and the tissue was subjected to histological and histomorphometric analysis. Finasteride and castration decreased prostate weight at day 21 by 65% and 93%, respectively. Castration decreased DNA content (micrograms per prostate) by a maximum of 88% at 14 days. Finasteride had no significant effect on DNA content after 4 days and decreased DNA content by a maximum of 52% at 14 days. When castrate prostate sections were stained for tissue transglutaminase, a marker of apoptotic cell death, a maximum of 23% of epithelial cells were stained by day 14 with a return to control levels by day 21. Finasteride caused a less intense increase in staining in which 16% of epithelial cells stained for tissue transglutaminase on day 9 with a return to baseline by day 14. When prostate sections were stained for DNA breaks, another marker of cell death, castration, caused a peak of staining on day 4 with 6% of epithelial cells staining and a return to near control levels by day 21. Finasteride-induced staining was less intense with peak staining at day 4 (0.7% of epithelial cells) and a return to control values by day 9. Morphometrics were used to assess the effect of castration and finasteride on prostate duct size and epithelial cell mass. After 4 days of finasteride treatment, the mean ductal mass decreased by 47%, with no significant change thereafter. The mean epithelial cell mass decreased by 15% on day 4 and 60% on day 9, with no further decrease thereafter. Castration caused a more rapid and greater decrease in both morphometric parameters with a 95% reduction in the mass of prostate ducts and a 93% decrease in epithelial cell mass by day 9. We conclude that castration induces a more profound involution of the rat ventral prostate than does 5 alpha-reductase inhibition. Cell loss occurs in both groups, but the degree of cell loss is less with finasteride.

The Value of Colonic Irrigations In Counteracting Auto-intoxication of Intestinal origin

The aim of the study was to investigate the anti-proliferative activity of brassinin and its derivatives on human cancer cell lines. We found that among twenty-one tested compounds, 1- methoxybrassinin exerted the most potent anti-proliferative activity in Caco-2 cells with IC50 8.2 (±1.2) μmol l−1. The flow cytometric analysis revealed a 1-methoxybrassinin-induced increase in the sub-G1 DNA content fraction which is considered to be a marker of apoptotic cell death. Apoptosis was also confirmed by DNA fragmentation assay. Moreover, quantitative real-time PCR showed that 1-methoxybrassinin upregulated the expression of pro-apoptotic Bax and downregulated the expression of anti-apoptotic genes Bcl-2 and Bcl-xL. The compound also increased activity of caspase-3, -7, cleaved PARP and decreased intracellular GSH content. The present study has assessed the in vitro anti-proliferative potential of 1-methoxybrassinin. The results generate a rationale for in vivo efficacy studies with this compound in preclinical cancer models.