Characterization of CD95 ligand (CD95L)-induced apoptosis in human tenon fibroblasts

Mitomycin C induces apoptosis in human epidural scar fibroblasts after surgical decompression for spinal cord injury

Numerous studies have shown that topical application of mitomycin C after surgical decompression effectively reduces scar adhesion. However, the underlying mechanisms remain unclear. In this study, we investigated the effect of mitomycin C on the proliferation and apoptosis of human epidural scar fibroblasts. Human epidural scar fibroblasts were treated with various concentrations of mitomycin C (1, 5, 10, 20, 40 μg/mL) for 12, 24 and 48 hours. Mitomycin C suppressed the growth of these cells in a dose- and time-dependent manner. Mitomycin C upregulated the expression levels of Fas, DR4, DR5, cleaved caspase-8/9, Bax, Bim and cleaved caspase-3 proteins, and it downregulated Bcl-2 and Bcl-xL expression. In addition, inhibitors of caspase-8 and caspase-9 (Z-IETD-FMK and Z-LEHD-FMK, respectively) did not fully inhibit mitomycin C-induced apoptosis. Furthermore, mitomycin C induced endoplasmic reticulum stress by increasing the expression of glucose-regulated protein 78, CAAT/enhancer-binding protein homologous protein (CHOP) and caspase-4 in a dose-dependent manner. Salubrinal significantly inhibited the mitomycin C-induced cell viability loss and apoptosis, and these effects were accompanied by a reduction in CHOP expression. Our results support the hypothesis that mitomycin C induces human epidural scar fibroblast apoptosis, at least in part, via the endoplasmic reticulum stress pathway.

Fas-Fas Ligand: Checkpoint of T Cell Functions in Multiple Sclerosis

Fas and Fas Ligand (FasL) are two molecules involved in the regulation of cell death. Their interaction leads to apoptosis of thymocytes that fail to rearrange correctly their T cell receptor (TCR) genes and of those that recognize self-antigens, a process called negative selection; moreover, Fas–FasL interaction leads to activation-induced cell death, a form of apoptosis induced by repeated TCR stimulation, responsible for the peripheral deletion of activated T cells. Both control mechanisms are particularly relevant in the context of autoimmune diseases, such as multiple sclerosis (MS), where T cells exert an immune response against self-antigens. This concept is well demonstrated by the development of autoimmune diseases in mice and humans with defects in Fas or FasL. In recent years, several new aspects of T cell functions in MS have been elucidated, such as the pathogenic role of T helper (Th) 17 cells and the protective role of T regulatory (Treg) cells. Thus, in this review, we summarize the role of the Fas–FasL pathway, with particular focus on its involvement in MS. We then discuss recent advances concerning the role of Fas–FasL in regulating Th17 and Treg cells’ functions, in the context of MS.

Co-treatment of suberoylanilide hydroxamic acid and mitomycin-C induces the apoptosis of rabbit tenon's capsule fibroblast and improves the outcome of glaucoma filtration surgery

PURPOSE

This study was undertaken to develop a new treatment modality that would be able to minimize fibrosis and provide better outcome with glaucoma filtration surgery (GFS).

METHODS

We examined whether co-treatment with mitomycin-C (MMC) and histone deacetylase inhibitor (HDACi) suberoylanilide hydroxamic acid (SAHA) efficiently induces apoptosis on rabbit Tenon's capsule fibroblasts (TCF) in vitro. We further examined the effect of co-treatment with SAHA and MMC on the alteration of IOP and the bleb survival in rabbits following GFS.

RESULTS

Co-treatment of MMC and SAHA efficiently induces apoptosis in TCFs via the up-regulation of p53 and increased phosphorylation of p53 on serine 15 and 392. Also, co-treatment of SAHA and low-dose MMC decreases IOP, prolongs bleb survival, and induces apoptosis of cells under the bleb area following GFS.

CONCLUSION

This study shows that a co-treatment of SAHA and MMC could improve the outcome of GFS.

Effects of daunorubicin and CD95L on retinal function in superfused vertebrate retina

Alternative treatments of proliferative vitreoretinopathy (PVR) are needed. The intravitreal application of daunorubicin combined with CD95 ligand (CD95L) could provide a new therapeutic strategy. The effects of this application on bovine retinal function were investigated. Bovine retina preparations were perfused with a standard solution preequilibrated with oxygen. The b-wave and, after the addition of aspartate, the photoreceptor potential P III of the electroretinogram (ERG) were recorded using Ag/AgCl electrodes. Stable ERG amplitudes were recorded, then daunorubicin was added to the solution for 45 minutes, also with the addition of CD95L antibody. Subsequently, the preparation was reperfused with the standard solution for 100 minutes, to allow for recovery. The reduction in b-wave amplitude was reversible and not significantly changed by the addition of 0.25 microg/mL CD95L antibody to 13 microM of daunorubicin. The reduction of the b-wave amplitude was significantly changed and only partly reversible within the recovery time using 40 microM and 80 microM of daunorubicin. The photoreceptor potential P III amplitude was not significantly changed for up to 80 microM of daunorubicin. The ERG showed toxic effects of daunorubicin above a concentration of 13 microM used therapeutically in humans. The combination with CD95L did not increase retinal toxicity. It is, therefore, concluded that daunorubicin may be applied intraocularly, combined with CD95L, without interfering with retinal function.

Induction of apoptosis as a proposed pathophysiological link between glaucoma and Helicobacter pylori infection

Although apoptosis is equally important both for the development and for the maintenance of homeostasis in some adult tissues, it can also be associated with disease processes. Current studies indicate that apoptosis is a mechanism of cell death in several important ocular and gastrointestinal diseases including glaucoma, and Helicobacter pylori (H. pylori)-induced upper gastrointestinal disorders and/or extraintestinal diseases, including autoimmune and neurodegenerative ones (Sjögren's syndrome, Guillain-Barre syndrome or Parkinson's disease). Glaucoma is also associated with similar autoimmune and neurodegenerative disorders, characterized by apoptotic loss of specific populations of neurons. Recently, a high prevalence of H. pylori infection has been recognized in patients with chronic open-angle glaucoma. In addition, H. pylori eradication may positively influence glaucoma parameters, thereby suggesting a possible causal link between H. pylori and glaucoma. H. pylori infection may influence the pathophysiology of glaucoma by releasing various proinflammatory and vasoactive substances, as well as by influencing apoptotic process; parameters that may also exert their own effects in the induction and/or progression of glaucomatous neuropathy. Importantly, H. pylori infection and glaucoma share the Fas/FasL and the mitochondria-mediated apoptotic pathways, thereby proposing an apoptotic link in the pathophysiology of both diseases.