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FADD is required for multiple signaling events downstream of the receptor Fas.

To identify essential components of the Fas-induced apoptotic signaling pathway, Jurkat T lymphocytes were chemically mutagenized and selected for clones that were resistant to Fas-induced apoptosis. We obtained five cell lines that contain mutations in the adaptor FADD. All five cell lines did not express FADD by immunoblot analysis and were completely resistant to Fas-induced death. Complementation of the FADD mutant cell lines with wild-type FADD restored Fas-mediated apoptosis. Fas activation of caspase-2, caspase-3, caspase-7, and caspase-8 and the proteolytic cleavage of substrates such as BID, protein kinase Cdelta, and poly(ADP-ribose) polymerase were completely defective in the FADD mutant cell lines. In addition, Fas activation of the stress kinases p38 and c-Jun NH2 kinase and the generation of ceramide in response to Fas ligation were blocked in the FADD mutant cell lines. These data indicate that FADD is essential for multiple signaling events downstream of Fas.

Adaptor Proteins, Signal Transducing↗

Chronic morphine induces up-regulation of the pro-apoptotic Fas receptor and down-regulation of the anti-apoptotic Bcl-2 oncoprotein in rat brain.

1. This study was designed to assess the influence of activation and blockade of the endogenous opioid system in the brain on two key proteins involved in the regulation of programmed cell death: the pro-apoptotic Fas receptor and the anti-apoptotic Bcl-2 oncoprotein. 2. The acute treatment of rats with the mu-opioid receptor agonist morphine (3-30 mg x kg(-1), i.p., 2 h) did not modify the immunodensity of Fas or Bcl-2 proteins in the cerebral cortex. Similarly, the acute treatment with low and high doses of the antagonist naloxone (1 and 100 mg x kg(-1), i.p., 2 h) did not alter Fas or Bcl-2 protein expression in brain cortex. These results discounted a tonic regulation through opioid receptors on Fas and Bcl-2 proteins in rat brain. 3. Chronic morphine (10-100 mg x kg(-1), 5 days, and 10 mg x kg(-1), 13 days) induced marked increases (47-123%) in the immunodensity of Fas receptor in the cerebral cortex. In contrast, chronic morphine (5 and 13 days) decreased the immunodensity of Bcl-2 protein (15-30%) in brain cortex. Chronic naloxone (10 mg x kg(-1), 13 days) did not alter the immunodensities of Fas and Bcl-2 proteins in the cerebral cortex. 4. The concurrent chronic treatment (13 days) of naloxone (10 mg x kg(-1)) and morphine (10 mg x kg(-1)) completely prevented the morphine-induced increase in Fas receptor and decrease in Bcl-2 protein immunoreactivities in the cerebral cortex. 5. The results indicate that morphine, through the sustained activation of opioid receptors, can promote abnormal programmed cell death by enhancing the expression of pro-apoptotic Fas receptor protein and damping the expression of anti-apoptotic Bcl-2 oncoprotein.

Animals↗

Induction of apoptosis mediated by fas receptor and activation of caspase-3 in MRL-+/+ or MRL-lpr/lpr murine oocytes.

The molecular mechanisms leading to ovarian follicular atresia in the typical pathways of programmed cell death remain to be clarified. Here we have demonstrated that the apoptotic signalling pathway in MRL-+/+ (MRL/+) murine oocytes is through the Fas receptor followed by the activation of caspase-3. In contrast, we found that the aberrant expression and dysfunction of the mutant Fas receptor in MRL-lpr/lpr (MRL/lpr) murine oocytes caused by insertion of the early transposable element (ETn) into the Fas gene were associated with an inability to activate the caspase cascade (especially caspase-3) and to induce nuclear DNA fragmentation. These findings indicate that the induction of apoptosis in MRL/lpr murine oocytes did not occur in the presence of a defective Fas receptor lacking the death domain to trigger the caspase cascade, suggesting a failure to induce ovarian follicular atresia.

Animals↗

Fas receptor signaling inhibits glycogen synthase kinase 3 beta and induces cardiac hypertrophy following pressure overload.

Congestive heart failure is a leading cause of mortality in developed countries. Myocardial hypertrophy resulting from hypertension often precedes heart failure. Understanding the signaling underlying cardiac hypertrophy and failure is of major interest. Here, we identified Fas receptor activation, a classical death signal causing apoptosis via activation of the caspase cascade in many cell types, as a novel pathway mediating cardiomyocyte hypertrophy in vitro and in vivo. Fas activation by Fas ligand induced a hypertrophic response in cultured cardiomyocytes, which was dependent on the inactivation of glycogen synthase kinase 3 beta (GSK3 beta) by phosphorylation. In vivo, lpr (lymphoproliferative disease) mice lacking a functional Fas receptor demonstrated rapid-onset left ventricular dilatation and failure, absence of compensatory hypertrophy, and significantly increased mortality in response to pressure overload induction that was accompanied by a failure to inhibit GSK3 beta activity. In contrast, Fas ligand was dispensable for the development of pressure overload hypertrophy in vivo. In vitro, neonatal cardiomyocytes from lpr mice showed a completely abrogated or significantly blunted hypertrophic response after stimulation with Fas ligand or angiotensin II, respectively. These findings indicate that Fas receptor signaling inhibits GSK3 beta activity in cardiomyocytes and is required for compensation of pressure overload in vivo.

Animals↗

The insulin-like growth factor 1 receptor induces transformation and tumorigenicity of ovarian mesothelial cells and down-regulates their Fas-receptor expression.

Cell proliferation and papillogenesis are growth factor-sensitive events in the ovarian mesothelium, the tissue source of ovarian epithelial cancer. To further investigate the regulation of cell proliferation in this tissue, rabbit ovarian mesothelial cells (OMC) were transfected in vitro with a CVN expression vector carrying the human gene for insulin-like growth factor 1 receptor (IGF-1R). The growth characteristics of IGF-1R transfectants (OMIR) and their response to IGF-1 were then compared with those of OMC in serumless HL-1 cultures. OMIR cells formed epithelial-like colonies and, even when nonconfluent, produced tridimensional structures reminiscent of papillae seen in ovarian serous epithelial tumors. After 3 and 7 days of exposure to IGF-1, OMIR cells grew approximately 20-fold (P < 0.05), and papillogenesis was 15- to 25-fold over similar events in OMC, respectively. Exposure to treatment with antisense oligonucleotides against IGF-1R mRNA inhibited OMIR growth rate by 70%. Western immunoblotting and flow cytometry revealed higher expression of IGF-1R in OMIR cells than in OMC. The reverse was true when Fas-receptor expression was evaluated. OMIR cells were clonogenic in 15% serum-rich soft agar assay (OMIR:OMC colony-forming ratio 150-200:1), and tumorigenic in nude mice in which high-grade carcinomas with occasional lung metastases were observed. These data suggest that IGF-1R plays a role in ovarian epithelial carcinogenesis. The overexpression of this receptor induces transformation and morphogenesis of OMCs via an autocrine mechanism. IGF-1R may down-regulate the Fas expression rendering transformed ovarian mesothelial cells resistant to apoptosis.

Animals↗

Effects of the tyrosine kinase inhibitor AG957 and an Anti-Fas receptor antibody on CD34(+) chronic myelogenous leukemia progenitor cells.

The hallmark of chronic myelogenous leukemia (CML) is the Philadelphia (Ph) chromosome that fuses genetic sequences of the BCR gene on chromosome 22 with c-ABL sequences translocated from chromosome 9. BCR/ABL fusion proteins have a dysregulated protein tyrosine kinase (PTK) activity exerting a key role in malignant transformation. Targeting the tyrosine kinase activity of BCR/ABL or using agents capable of triggering apoptosis might represent attractive therapeutic approaches for ex vivo purging. AG957, a member of the tyrphostin compounds, exerts a selective inhibition of p210(BCR/ABL) tyrosine phosphorylation. We report here that preincubation of CML or normal CD34(+) cells with graded concentration of AG957 (1 to 100 micromol/L) resulted in a statistically significant, dose-dependent suppression of colony growth from multipotent, erythroid, and granulocyte-macrophage progenitors as well as the more primitive long-term culture-initiating cells (LTC-IC). However, AG957 doses causing 50% inhibition (ID50) of CML and normal progenitors were significantly different for multilineage colony-forming units (CFU-Mix; 12 v 64 micromol/L; P =.008), burst-forming unit-erythroid (BFU-E; 29 v 89 micromol/L; P =.004), colony-forming unit-granulocyte-macrophage (CFU-GM; 34 v 85 micromol/L; P =.004), and LTC-IC (43 v 181 micromol/L; P =.004). In 5 of 10 patients, analysis of BCR/ABL mRNA on single progenitors by reverse transcription-polymerase chain reaction showed that AG957 at 50 micromol/L significantly reduced the mean (+/-SD) percentage of BCR/ABL-positive progenitors (92% +/- 10% v 33 +/- 5%; P =.001). Because AG957 treatment resulted in significantly higher percentages of apoptotic cells (30% v 9%) in the BCR/ABL-transfected 32DLG7 cells as compared with 32D-T2/93 cells (BCR/ABL-negative), we investigated the combined effects of AG957 with the anti-Fas receptor (Fas-R) monoclonal antibody CH11 that triggers apoptosis. As compared with AG957 alone, the sequential treatment of CML CD34(+) cells with AG957 (1 micromol/L) and CH11 (1 microgram/mL) increased CFU-Mix, BFU-E, and CFU-GM growth inhibition by 1.6-fold, 3-fold, and 4-fold, respectively. In contrast, the treatment of normal CD34(+) cells with AG957 and CH11 failed to enhance AG957-induced colony growth inhibition. We conclude that (1) AG957 inhibits in a dose-dependent manner CML CD34-derived colony formation by both primitive LTC-IC as well as committed CFU-Mix, BFU-E, and CFU-GM; (2) this growth inhibition is associated with the selection of a substantial amount of BCR/ABL-negative progenitors; and (3) the antiproliferative effect of AG957 is dramatically increased by combining this compound with the anti-Fas-R antibody CH11. These data may have significant therapeutic applications.

Adult↗

Activation of Fas receptor modulates cytochrome P450 3A4 expression in human colon carcinoma cells.

The Fas (CD95, APO-1) receptor is a transmembrane cell surface receptor that mediates apoptosis in many cell types when bound by the Fas ligand or cross-linked by agonistic anti-Fas antibodies. Fas activation engages a potent and rapid signaling mechanism in a variety of cell types. In the present study, we have investigated the effects of Fas receptor activation on CYP3A4 expression in human colon carcinoma HT-29 cells. The intracellular ceramide levels were significantly enhanced by the treatment with the anti-Fas antibodies and both CYP3A4 protein and mRNA expression was suppressed by Fas activation in a dose-dependent manner. Immunoblot analyses showed that the expression of iNOS protein was significantly stimulated by an anti-Fas antibody treatment in HT-29 cells. Fas receptor activation also increased the generation of reactive oxygen species, and N-acetylcysteine, a well-known antioxidant, could block Fas-mediated iNOS induction. These results show that the Fas receptor-mediated signaling pathways modulate CYP3A4 expression in human colon cancer cells. Overall, iNOS induction and P450 3A4 suppression by Fas activation may cause toxic cellular damage in gastrointestinal tissues.

Adenocarcinoma↗

Regulatable expression of the interferon-induced double-stranded RNA dependent protein kinase PKR induces apoptosis and fas receptor expression.

PKR is an interferon-induced dsRNA-dependent protein kinase involved in the antiviral response as well as in cell growth and differentiation. Studies using a transdominant negative mutant of PKR also have implicated the kinase in tumor suppression and apoptosis. However, functional studies of PKR have been hampered by the lack of a suitable expression system. In this study, we used a tetracycline-regulated inducible system in NIH3T3 cells to investigate the involvement of PKR in programmed cell death (apoptosis). We show that expression of wild-type PKR causes apoptosis and correlates with increased mRNA levels for the Fas receptor, a member of the tumor necrosis family of proteins. Expression of an inactive form of PKR (K296R) or the vector alone did not induce apoptosis or elevate Fas mRNA levels. Our results clearly demonstrate that expression of an active form of PKR triggers apoptosis, possibly through upregulation of the Fas receptor.

3T3 Cells↗

Cytochrome c release upon Fas receptor activation depends on translocation of full-length bid and the induction of the mitochondrial permeability transition.

In Jurkat cells Bid was cleaved upon activation of the Fas receptor with an anti-Fas antibody. The caspase-8 inhibitor benzyloxycarbonyl-Ile-Glu(OMe)-Thr-Asp(OMe)-CH(2)F (IETD) prevented the cleavage of Bid and the loss of viability. The nuclear enzyme poly(ADP-ribose)polymerase (PARP) was also cleaved upon the activation of caspases, and IETD similarly prevented PARP cleavage. The PARP inhibitor 3-aminobenzamide (3-AB) restored the cell killing in the presence of IETD, an effect that occurred without restoration of the cleavage of Bid or PARP. In the presence of 3-AB and IETD, translocation occurred of full-length Bid to the mitochondria. The induction of the mitochondrial permeability transition (MPT) was documented by the cyclosporin A (CyA) sensitivity of the release of cytochrome c, the release of malate dehydrogenase from the mitochondrial matrix, the loss of the mitochondrial membrane potential, and the pronounced swelling of these organelles, as assessed by electron microscopy. In addition to preventing all evidence of the MPT, CyA prevented the loss of cell viability, without effect on the cleavage of either Bid or PARP. The prevention of PARP cleavage by inhibition of caspase-3 resulted in a 10-fold activation of the enzyme and a resultant depletion of NAD and ATP. The PARP inhibitor 3-AB prevented the loss of NAD and ATP. Depletion of ATP by metabolic inhibitors similarly prevented the cell killing. It is concluded that the cleaving of PARP in Fas-mediated apoptosis allowed expression of an energy-dependent cell death program that included the translocation of full-length Bid to the mitochondria with induction of the MPT.

Actins↗

Expression of Fas-receptor on basal cell carcinomas after treatment with imiquimod 5% cream or vehicle.

Treatment with imiquimod 5% cream, capable of inducing interferon (IFN)-alpha, effectively cures basal cell carcinoma (BCC), both clinically and histologically. IFN-alpha induces expression of CD95-receptor (FasR) on BCC cells, which normally fail to express Fas receptor (FasR). Expression of the FasR is postulated to lead to apoptosis via CD95 receptor-CD95 ligand (FasL) interaction. Absence of this receptor may be responsible for the longevity of the cells of BCCs by preventing them undergoing 'suicidal' apoptosis, as well as apoptosis induced by neighbouring BCC cells and/or by infiltrating T-lymphocytes. We examined the expression of FasR on BCC after very short-term exposure to imiquimod 5% cream or vehicle. In a double-blind study, 10 patients with BCC applied either imiquimod (n = 5) or vehicle (n = 5) five times per week for up to 2 weeks. At the end of treatment, the treated area was excised and examined for the presence or absence of FasR by immunoperoxidase staining of rat antihuman FasR with haematoxylin and eosin counterstaining. Histologically, BCC cells were present in all (5/5) of the vehicle-treated BCCs and in 4/5 of the imiquimod-treated BCCs. BCC cells expressed FasR in 3/4 imiquimod-treated BCCs but in none (0/5) of the vehicle-treated tumours. T-lymphocytes apposed to BCC cells were evident in all three imiquimod-treated BCCs expressing FasR and in none of the FasR-negative, vehicle-treated BCCs. Imiquimod-induced FasR-mediated apoptosis may contribute to the effectiveness of imiquimod 5% cream for the treatment of BCC.

Adjuvants, Immunologic↗

Modulation of Fas receptor proteins and dynamin during opiate addiction and induction of opiate withdrawal in rat brain.

The Fas receptor is involved in the regulation of apoptosis but also can function as a non-apoptotic signal transducer. This study was mainly designed to quantitate Fas proteins in rat brain during heroin addiction and opiate withdrawal. In rat, mouse and human brains, and in SH-SY5Y cells, similar forms of Fas were immunodetected with different antibodies (i.e., 35 kDa native Fas and 48- and 51-kDa glycosylated Fas). Acute (2 h) treatments with the micro-opioid receptor agonists heroin (10 mg/kg) and morphine (30 mg/kg) increased the immunodensity of native Fas (124% and 36%) but not that of glycosylated Fas in the cerebral cortex. Chronic (5 days) heroin (5-30 mg/kg) and morphine (10-100 mg/kg) were also associated with increased native Fas (76% and 45%) and with different expressions of glycosylated Fas. In heroin-dependent rats, opiate withdrawal (48 h) resulted in a sustained increase in native Fas (107%) and in up-regulation of 51 kDa glycosylated Fas (51%). Acute treatments with selective delta-receptor (SNC-80, 10 mg/kg) or kappa-receptor (U 50488-H, 10 mg/kg) agonists did not alter the content of native or glycosylated Fas. Chronic pentazocine (10-80 mg/kg, 5 days), a mixed opiate drug and sigma(1) receptor agonist, decreased native (48%) and glycosylated (38-82%) Fas proteins. Similarly, the selective sigma(1) agonist (+)-SKF 10047 also decreased native Fas (37%) and the effect was blocked by the sigma(1) antagonist BD 1063. Brain dynamin was up-regulated by acute and/or chronic heroin (30-39%), morphine (47-85%), pentazocine (51%) and heroin withdrawal (74%). The main results indicate that chronic heroin/morphine treatment and heroin withdrawal are associated with up-regulation of 35 kDa native Fas (and with different expressions of glycosylated Fas), and also with concomitant increases of dynamin in rat brain.

Animals↗

The Fas receptor-1,4,5-IP3 cascade: a potential target for treating heart failure and arrhythmias.

Activation of the Fas receptor in various cell types, including myocytes, triggers apoptotic as well as nonapoptotic effects. Recent studies suggest that Fas activation in the heart participates in the development of major pathologies such as myocarditis and ischemic/reperfusion insults, which are manifested by arrhythmias and mechanical dysfunction. To decipher the contribution of the Fas/FasL pathway to myocardial pathologies, we have investigated the functional consequences of Fas activation in normoxic and hypoxic ventricular myocytes. Our major findings were as follows. (1) Although Fas is constitutively expressed in ventricular myocytes, normoxic myocytes are resistant to Fas-mediated apoptosis. In contrast, hypoxia predisposes myocytes to apoptosis induced by Fas activation. The underlying mechanism is a shift in the balance between proapoptotic proteins (including Fas) and antiapoptotic proteins toward the former. (2) In normoxic myocytes, Fas activation causes a wide range of functional disturbances, which include reduction in resting potential and action potential amplitude, prolonged action potential duration, development of delayed and early after-depolarizations, occasionally culminating into arrhythmias, diastolic [Ca(2+)](i) level increase, decreased I(to) and increased I(Ca,L). (3) The above-mentioned effects in normoxic myocytes (but not Fas-mediated apoptosis in hypoxic myocytes) depend on the phospholipase C --> 1,4,5-IP(3) --> SR [Ca(2+)](i) release cascade. (4) Inhibition of tyrosine kinases with genistein blocks both the apoptotic and nonapoptotic consequences of Fas activation in ventricular myocytes. Based on these studies we propose that tyrosine phosphorylation in ventricular myocytes can serve as a novel potential target for attenuating Fas-mediated dysfunction in normoxic and hypoxic myocardium.

Animals↗

Caspase-dependent initiation of apoptosis and necrosis by the Fas receptor in lymphoid cells: onset of necrosis is associated with delayed ceramide increase.

Engagement of the Fas receptor promotes apoptosis by activation of caspases. In addition, alterations in plasma membrane lipid orientation and intracellular ceramide levels are often observed. In A20 B-lymphoma cells, FasL-induced cell death and phosphatidylserine (PS) externalization were completely prevented by the generic caspase inhibitor z-VAD-fmk. By contrast, the caspase-3 inhibitor Ac-DEVD-cho only partially restored cell viability and had no effect on surface exposure of PS. Flow cytometric analysis after FasL treatment identified two populations of dead cells. In one, death was dependent on caspase-3 and paralleled by DNA fragmentation and cell shrinkage. In the second, death occurred in the absence of caspase-3 activity and apoptotic features but was also blocked by zVAD-fmk. By morphological criteria these were identified as apoptotic and necrotic cells, respectively. Using fluorescent substrates, caspase-3 activity was detected only in the apoptotic cell population, whereas caspase-8 activity was detected in both. Both forms of caspase-8-dependent cell death were also detected downstream of Fas in Jurkat T-cells, where Fas-dependent PS externalization and delayed ceramide production, which is similar to results shown here in A20 cells, have been reported. However, for Raji B-cells, lacking lipid scrambling and ceramide production in response to Fas activation, only apoptosis was detected. Short-chain C2- or C6-ceramides, but not the respective inactive dihydro compounds or treatment with bacterial sphingomyelinase, induced predominantly necrotic rather than apoptotic cell death in A20 B-, Raji B- and Jurkat T-cells. Thus, delayed elevation of ceramide is proposed to promote necrosis in those Fas-stimulated cells where caspase-8 activation was insufficient to trigger caspase-3-dependent apoptosis.

Apoptosis↗

Electrophysiologic perturbations and arrhythmogenic activity caused by activation of the Fas receptor in murine ventricular myocytes: role of the inositol trisphosphate pathway.

INTRODUCTION: Experimental evidence suggests a major role for Fas receptor activation in a wide range of myocardial pathologies. Because clinical situations, which are likely to be associated with Fas activation, are accompanied by a variety of ventricular arrhythmias, the major goal of this study was to investigate the ionic mechanisms responsible for these phenomena. METHODS AND RESULTS: To delineate the origin of Fas-mediated electrophysiologic perturbations, the transient outward K+ current I(to) and the L-type Ca2+ current I(Ca,L) were studied in murine ventricular myocytes treated with the Fas-activating monoclonal antibody Jo2. Jo2 decreased I(to) (4.36 +/- 1.2 pA/pF vs 17.48 +/- 2.36 pA/pF in control, V(M) = +50 mV; P < 0.001) and increased I(Ca,L) (-13.17 +/- 1.38 pA/pF vs -3.94 +/- 0.78 pA/pF in control, V(M) = 0 mV; P < 0.001). Pretreatment of ventricular myocytes with ryanodine or thapsigargin prevented the electrophysiologic effects of Jo2, suggesting that [Ca2+]i elevation is important for Fas-mediated action. In agreement with our previous studies demonstrating dependence of Fas-based myocyte dysfunction on an intact inositol trisphosphate (1,4,5-IP3) pathway, the effects of Jo2 on I(to) and I(Ca,L) were prevented by the phospholipase C (generates 1,4,5-IP3) blocker U73122, and by xestospongin C (tested with I(to)), a specific blocker of IP3-operated sarcoplasmic reticulum Ca2+ release channels. Furthermore, intracellular perfusion with 1,4,5-IP3, but not with 1,3,4-IP3, caused electrophysiologic effects resembling those of Jo2. CONCLUSION: Decreased I(to) and increased I(Ca,L) underlie Fas-induced action potential alterations and arrhythmias in murine ventricular myocytes, effects that appear to be mediated by 1,4,5-IP3-induced intracellular calcium release.

Animals↗

Ceramide, a mediator of interleukin 1, tumour necrosis factor alpha, as well as Fas receptor signalling, induces apoptosis of rheumatoid arthritis synovial cells.

OBJECTIVES: To examine the effects of ceramide, which is a lipid second messenger of cell surface receptors, including tumour necrosis factor alpha (TNF alpha), interleukin 1 (IL1), and Fas receptors, on rheumatoid arthritis (RA) synovial cells. METHODS: Synovial cells from RA patients and normal skin fibroblasts were cultured with cell permeable ceramide (C2-ceramide). Apoptosis was assessed by microscopic observation of morphological changes, nuclear staining, and DNA electrophoresis. DNA synthesis was examined by thymidine incorporation. RESULTS: C2-ceramide induced reversible morphological changes of synovial cells such as cell rounding within four hours. Subsequently, irreversible nuclear changes characteristic to apoptosis were observed at 48 hours. DNA synthesis was not promoted. The addition of ceramide exerted similar effects on cultured dermal fibroblasts. CONCLUSION: Ceramide induced apoptosis in RA synovial cells. Ceramide could be a second messenger specific for apoptosis of RA synovial cells.

Apoptosis↗

Proinflammatory cytokines, soluble Fas receptor, nitric oxide and angiotensin converting enzyme in congestive heart failure.

We measured serum interleukin-2 receptor (sIL-2R), tumor necrosis factor-a (TNF-a), Fas receptor (sFas), nitric oxide (NO), and angiotensin converting enzyme (ACE) activity in 45 patients with congestive heart failure (CHF) of different etiologies. The relatioship between these bioindices and the severity of heart failure was analysed. Patients were classified according to the etiology of heart failure into: 15 patients with rheumatic valvular heart disease (RHD), 17 with ischemic heart disease (IHD) and 13 with idiopathic dilated cardiomyopathy (DCM). Patients were further classified according to severity of CHF following the New York Heart Association classification (NYHA) into: NYHA class II (n= 7), NYHA class III (n=20) and NYHA class IV (n=18). Eighteen healthy subjects were included as controls. Serum sIL-2R, TNF-alpha and sFas levels were determined by ELISA while serum NO and ACE levels were measured by colorimetric methods. Doppler Echocardiography was performed for all participants. Levels of sIL-2R, TNF-alpha, sFas, NO, and ACE were significantly higher in CHF patients than controls. Levels of the bioindices varied according to the CHF etiology. TNF-a level was the only one that had significant differences among different subgroups (RHD, IHD and DCM). The levels of sIL-2R, TNF-alpha, NO and sFas in patients with NYHA class IV were significantly higher than class II or III. Moreover, sIL-2R, TNF-alpha and NO levels were significantly higher in patients with diastolic dysfunction than patients with normal diastolic function. A significant positive correlations were found between sFas and both TNF-alpha and sIL-2R and between TNF-alpha and both NO and diastolic function. In addition, significant positive correlations were found between TNF-alpha and sIL-2R in both IHD and RHD patients and between sIL-2R and both ACE in IHD patients and diastolic function in DCM patients. It is concluded that a relationship exists between immune system activation, apoptosis and renin- angiotensin system in CHF and this may play a significant role in the pathophysiology and prognosis of the disease.

Adult↗

Human autoimmune lymphoproliferative syndrome, a defect in the apoptosis-inducing Fas receptor: a lesson from the mouse model.

The immune response is regulated not only by the proliferation, differentiation, and activation of cells, but also by programmed cell death, called apoptosis. Fas ligand expressed in activated T cells binds to its receptor, Fas, and induces apoptosis in target cells. Two mouse mutations that cause autoimmune disease, lpr (lymphoproliferation) and gld (generalized lymphoproliferative disease), are mutations in Fas and FasL genes, respectively. Human patients showing phenotypes (Canale-Smith syndrome or autoimmune lymphoproliferative syndrome) similar to those in lpr mice also carry mutations in Fas. This is a good example of a case in which the identification of a mouse mutation has led to the understanding of a human disease.

Amino Acid Sequence↗

[Fas receptor expression on peripheral blood T lymphocytes in patients with secondary progressive multiple sclerosis].

The percentages of CD4, CD8 subsets and Fas co-expression on them were assessed in secondary progressive multiple sclerosis (MS) patients and in control group. The MS patients were subdivided into two groups. The first group--active, consisted of patients who progressed by one or more degrees on EDSS scale in the preceding year, while the second group--stable, consisted of patients who showed no progression of the disease in the same period of time. Quantitative assessment of the individual subsets and Fas co-expression was carried out with the use of monoclonal anti-CD4, anti-CD8, as well as anti-CD95 antibodies, and Pas/Dako, Galaxy flow cytometer. There were no significant differences in CD4, CD8 subsets among the active, stable MS patients, and the control group. In the active MS group Fas co-expression on both subsets was significantly higher, as compared to controls. In the stable MS group, as compared to controls, a significantly higher Fas co-expression on CD8 subsets was observed. The investigation of Fas receptor expression on T lymphocytes in peripheral blood may be useful in order to monitor the progression of clinical activity in secondary progressive MS.

Antibodies, Monoclonal↗