C6orf120 gene knockout in rats mitigates concanavalin A­induced autoimmune hepatitis via regulating NKT cells.

OBJECTIVE: To elucidate the role of the functional unknown gene C6orf120 in the pathogenesis of AIH and its mechanism of action, using C6orf120 knockout rats. METHODS: An autoimmune hepatitis model was established with 35 mg/kg intravenous injection of concanavalin A (Con A) in C6orf120-knockout (C6orf120-/-) and wild-type (WT) rats. Rats were sacrificed after administering Con A for 0, 12, and 24 h. The peripheral blood, liver, spleen, and mesenteric lymph nodes were collected for follow-up studies. RESULTS: C6orf120 knockout significantly decreased the serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and improved the histological damage in Con A-induced autoimmune liver injury.Loss of C6orf120 function significantly increased the frequency of CD3+ CD161+ NKT cells in the peripheral blood, liver, and spleen; downregulated the expression of CD314 (NKG2D) in the liver, spleen, and mesenteric lymph nodes; reduced the expression of inflammatory cytokines and chemokines; and suppressed the mRNA and protein expression of Fas and FasL in the liver. Additionally, C6orf120 knockout significantly downregulated the expression of p-JAK1, p-JAK2, p-STAT1, and p-STAT3 in liver tissue. CONCLUSION: The protective effect of C6orf120 knockout against Con A-induced hepatitis may be due to the inhibition of NKT cell activation, restriction of cytokine and chemokine activities, inhibition of JAK-STAT and Fas/FasL signaling pathway activation, and reduction in liver inflammation and hepatocyte apoptosis.

LncRNA LINC00324 is upregulated in intervertebral disk degeneration and upregulates FasL in nucleus pulposus cells.

BACKGROUND: It has been reported that long intergenic non-protein-coding RNA 324 (LINC00324) promotes liver cancer by upregulating Fas ligand (FasL), which is a major player in intervertebral disk degeneration (IDD), indicating the involvement of LINC00324 in IDD. This study was carried out to investigate the interaction between LINC00324 and FasL in IDD. METHODS: Plasma samples were collected from both IDD (n = 60) and healthy controls (n = 60). The expression of LINC00324 and FasL in plasma was determined by RT-qPCR. The interactions between LINC00324 and FasL in nucleus pulposus (NP) cells were analyzed by overexpression experiments. RESULTS: LINC00324 and FasL were upregulated in IDD patients, and they were positively correlated. After treatment, the expression levels of FasL and LINC00324 were significantly decreased. In NP cells, overexpression of LINC00324 increased the expression of FasL at both mRNA and protein levels, while overexpression of FasL did not affect the expression of LINC00324. CONCLUSION: LINC00324 may upregulate FasL in IDD to promote disease progression.

Altered mRNA expression levels of autophagy- and apoptosis-related genes in the FOXO pathway in schizophrenia patients treated with olanzapine.

This study attempted to analyze the alterations in the mRNA expression levels of autophagy- and apoptosis-related genes in the forkhead box transcription factor O (FOXO) pathway in schizophrenia patients before and after olanzapine treatment. For a total of 32 acute schizophrenic inpatients, clinical data with PANSS were obtained before and after four weeks of olanzapine treatment (mean dose 14.24 ± 4.35 mg/d) along with data from 32 healthy volunteers. The mRNA expression levels of the FOXO pathway genes were measured by real-time qPCR after fasting venous blood was collected and analyzed. The mRNA expression levels of FOXO1, FOXO3A, FASLG, and BCL2L11 were observed to be significantly decreased in acute schizophrenia patients. After four weeks of olanzapine treatment, the expression levels of the first three genes were further reduced, but BCL2L11 expression levels were not significantly changed. The pairwise correlations between the mRNA expression level of FASLG and those of the other three genes were not observed in acute schizophrenia patients, while these relationships were observed in healthy controls. After olanzapine treatment, the FASLG mRNA expression level was restored and exhibited a pairwise correlation with the FOXO3A and BCL2L11 mRNA expression levels but not with the FOXO1 mRNA expression level, and FASLG mRNA expression was also correlated with the duration of the disease. The statuses and correlations of the mRNA expression levels of FOXO pathway-related genes were altered in schizophrenia patients and were affected by olanzapine treatment and the duration of the disease.

TCDD attenuates EAE through induction of FasL on B cells and inhibition of IgG production.

Previously we demonstrated that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) suppressed experimental autoimmune encephalomyelitis (EAE), a model to study multiple sclerosis (MS), through induction of regulatory T cells (Tregs) and suppression of effector T cell function in the spleen. Since B cells and specifically regulatory B cells (Bregs) have been shown to be so critical in the pathology associated with EAE and MS, we wanted to determine whether TCDD could also induce Bregs. We specifically hypothesized that a Fas ligand (FasL)+ Breg population would be induced by TCDD in EAE thereby triggering apoptosis in Fas-expressing effector T cells as one mechanism to account for inhibition of T cell function by TCDD. TCDD (0.1-2.5 µg/kg/day administered orally for 12 days) modestly increased the percentage of FasL + B cells in the spleen and spinal cord in TCDD-treated EAE mice. However, we did not detect significant increases in percentages of FasL + B cells using TCDD in vitro in mouse splenocytes or human peripheral blood mononuclear cells (PBMCs). Part of the modest effect by TCDD was likely related to the localized expression of FasL; for instance, in the spleen, FasL was more highly expressed by IgMhiIgDlo marginal zone (MZ) B cells, but IgMloIgDhi follicular (FO) B cells were more responsive to TCDD. Consistent with our observation of modest upregulation of FasL, we also observed modest changes in mitochondrial membrane potential in T cells co-cultured with isolated total B cells or IgM-depleted (i.e., FO-enriched) B cells from TCDD-treated EAE mice. These data suggest that while small microenvironments of apoptosis might be occurring in T cells in response to TCDD-treated B cells, it is not a major mechanism by which T cell function is compromised by TCDD in EAE. TCDD did robustly suppress IgG production systemically and in spleen and spinal cord B cells at end stage disease. Thus, these studies show that TCDD's primary effect on B cells in EAE is compromised IgG production but not FasL + Breg induction.

Regulation of Fas in response to bortezomib and epirubicin in colorectal cancer cells.

Bortezomib is a reversible proteasome inhibitor affects the ubiquitin-proteasome mechanism to kill cancer cells, and inhibition of the proteasome modulates the expression of multiple target genes at the transcriptional level. Epirubicin is known as an anthracycline agent that interferes with DNA and RNA synthesis, and it can be used with other chemotherapeutic drugs in the treatment of post-surgical breast cancer. Epirubicin may have an anti-tumor effect against broad-spectrum tumor cells. However, it is a non-specific chemotherapeutic agent that can cause high toxicity if not used in appropriate doses. Here, we hypothesize that a combination treatment of bortezomib and epirubicin will induce immunogenic cell death in colorectal cancer cells by increasing expression of death receptors such as Fas, which will make these cancer cells more susceptible to Fas/FasL mediated tumor cell killing. Our data demonstrate that a combination of bortezomib and epirubicin significantly increases the sensitivity of colorectal carcinoma cells, but not healthy non-malignant epithelial cells, to apoptosis. The combination treatment significantly upregulates the transcriptional activation of Fas in colorectal cancer cells but not in normal cells. Our results suggest that combining bortezomib and epirubicin may simultaneously enhance tumor immunogenicity and the induction of antitumor immunity.

Topiramate Reverses Physiological and Behavioral Alterations by Postoperative Cognitive Dysfunction in Rat Model Through Inhibiting TNF Signaling Pathway.

This study aimed to investigate the effects of topiramate (TPM) on rats with postoperative cognitive dysfunction (POCD) and elucidate the underlying mechanism. Differentially expressed genes in propofol-treated group and vehicle control group were filtered out and visualized in heatmap based on R program. POCD rat models were established for validation of TPM's anti-inflammatory action and Morris water maze (MWM) test was employed for assessment of spatial learning and memory ability of rats. Hematoxylin and eosin (HE) staining was applied to detect the neurodegeneration, and the apoptosis status was detected using TUNEL assay. In vitro, hippocampal microglia was treated with lipopolysaccharide or TPM to validate the TPM's anti-inflammatory action. Cell apoptosis was detected with flow cytometry. Inflammatory factors were detected by enzyme-linked immunosorbent assay, and factor-associated suicide (Fas), Fas-associated protein with death domain (FADD) expression were detected by western blot. As results, TPM administration improved the spatial learning and memory ability in POCD rat by decreasing the expression levels of Fas, FADD, and inflammatory factors (tumor necrosis factor-α, TNF-α; interleukin-1ß, IL-1ß; interleukin-6, IL-6) in POCD rats. In addition, TPM down-regulated cell apoptotic rate to suppress POCD by decreasing the expression of Caspase8, Bcl2-associated X (Bax), and poly ADP-ribose polymerase-1 (PARP1) yet enhancing B-cell lymphoma-2 (Bcl-2) expression. Besides, inhibition of Fas enhanced TPM-induced down-regulation of apoptosis of neuronal cell in hippocampus tissues of POCD rats. Our results revealed that treatment of POCD rats with TPM could suppress neuronal apoptosis in the hippocampus tissues, and the neuroprotective effects of TPM may relate with the regulation of tumor necrosis factor (TNF) signaling pathway.

Effects of 5-FU and anti-EGFR antibody in combination with ASA on the spherical culture system of HCT116 and HT29 colorectal cancer cell lines.

The aim of this study was to examine the effects of 5­fluorouracil (5­FU), anti­epidermal growth factor receptor (EGFR) antibody and aspirin (ASA) on the characteristics of two CRC cell lines, HCT116 and HT29, maintained in a spherical culture system. We observed that the morphology of both the HCT116 and HT29 cell­derived spheres was significantly impaired and the size of the colonospheres was markedly reduced following treatment with the aforementioned three drugs. In contrast to adherent cultures, the spherical cultures were more resistant to the tested drugs, as was reflected by their capacity to re­create the colonospheres when sustained in serum­free medium. Flow cytometric analysis of the drug­treated HCT116 cell­derived spheres revealed changes in the fraction of cells expressing markers of cancer stem cells (CSCs), whereas the CSC phenotype of HT29 cell­derived colonospheres was affected to a lesser extent. All reagents enhanced the percentage of non­viable cells in the colonospheres despite the diminished fraction of active caspase­3­positive cells following treatment of the HT29 cell­derived spheres with anti­EGFR antibody. Increased autophagy, assessed by acridine orange staining, was noted following the incubation of the HT29­colonospheres with ASA and 5­FU in comparison to the control. Notably, the percentage of cyclooxygenase (COX)­2­positive cells was not affected by ASA, although its activity was markedly elevated in the colonospheres incubated with anti­EGFR antibody. On the whole, the findings of this study indicate that all the tested drugs were involved in different cellular processes, which suggests that they should be considered for the combined therapeutic treatment of CRC, particularly for targeting the population of CSC­like cells. Thus, cancer cell­derived spheres may be used as a preferable model for in vitro anticancer drug testing.

Defective FasL expression is associated with increased resistance to melanoma liver metastases and enhanced natural killer cell activity.

The objective was to determine if the absence of FasL signaling would affect melanoma liver metastases by influencing the antimelanoma properties of liver natural killer (NK) cells. Melanoma liver metastases were induced in wild-type C57BL/6 mice and the gld/gld mutant C57BL/6 mouse strain that expresses a defective form of FasL (CD95L) that fails to engage and signal via the Fas receptor (CD95). Liver metastases were produced by intrasplenic injection of B16LS9 melanoma cells. Liver NK cell activity directed against murine B16LS9 melanoma cells was determined in a 24 h in-vitro cytotoxicity assay. Liver NK cells, NK T cells, and the NK cell surface activation marker, NKG2D, were measured by flow cytometry. Mice expressing defective FasL displayed reduced, rather than enhanced, melanoma liver metastases that coincided with increased liver NK cell-mediated tumor cell cytotoxicity. Enhanced cytotoxicity was not mediated by perforin, tumor necrosis factor-α, or tumor necrosis-associated apoptosis-inducing ligand but was closely associated with elevated interferon-γ in the tumor-bearing liver. FasL-defective gld/gld mice also displayed reduced numbers of liver NK T cells, which have been previously implicated in suppression on liver NK cell activity. The absence of functional FasL in the liver correlates with a heightened, not diminished, resistance to melanoma liver metastases. The resistance to liver metastases coincides with a significant, albeit transient, increase in liver NK cytotoxicity and elevated levels of interferon-γ in the liver.

Effect of erythropoietin on Fas/FasL expression in brain tissues of neonatal rats with hypoxic-ischemic brain damage.

Hypoxic-ischemic brain damage (HIBD) occurs due to intrauterine hypoxia ischemia influencing the energy supply for fetal brain cells, which affects the metabolism of the brain to make the brain suffer a severe damage. Erythropoietin (EPO), which regulates hemacytopoiesis, is a kind of cytokine. EPO is sensitive to hypoxia ischemia. In this study, we aimed to investigate the effect of EPO on the expression of Fas/FasL in brain tissues of neonatal rats with HIBD. Neonatal rats were assigned randomly to sham, HIBD, and EPO groups. Five time points for observation were 6, 12, 24, 48, and 72 h after the HIBD rat model had been established, respectively. In the HIBD group, Fas/FasL expression began to rise at 6 h, reached the peak at 12-24 h, and dropped from 24 h. In the EPO group, the expression of Fas/FasL was lower than those in HIBD group at 12, 24, and 48 h (P<0.05). Our findings suggest that EPO may reduce cell apoptosis after hypoxic-ischemic damage through reduction of the expression of Fas and FasL, and that optimal therapeutic time window is 6-24 h after HIBD.

Human CD8 T-cell activation in acute and chronic chikungunya infection.

There is a need for more detailed elucidation of T-cell immunity in chikungunya infection. CD8 T cells are one of main actors against viruses. Here, we analysed CD8+ T lymphocytes from patients in the acute and chronic phases of chikungunya disease (CHIKD). Our results demonstrate that CD8+ T cells expressed higher ex vivo granzyme B, perforin and CD107A expression in patients in the acute phase of CHIKD compared with healthy individuals and higher ex vivo expression of CD69, interleukin-17A, interleukin-10 and CD95 ligand, and co-expression of CD95/CD95 ligand. These results elucidate the importance of these lymphocytes, demonstrating immune mechanisms mediated in human chikungunya infection.

Magnetic nanoparticle-mediated gene therapy to induce Fas apoptosis pathway in breast cancer.

CD95 (Fas) is a complex integral protein that can be expressed in many cells. It induces apoptosis when interacted with its ligand CD95L (FasL). However, cancer cells are resistant to CD95-induced apoptosis because of the changes in death domain (DD) of CD95 (procaspase-8 and c-Flip). In this study, magnetic nanoparticles and lipid-based gene transfection methods were performed to provide active Fas expression in breast cancer cells. Plasmid DNA (pDNA), which can express both human Fas and GFP, was transfected to MCF-7 breast cancer cells. Expression of c-FLIP and caspase-8 and effect of monoclonal antibody FasL for apoptosis stimulation were investigated. Also transfection success of methods and effects on surface protein were compared. Western blot results indicated that MCF-7 cells do not express caspase-8 but express large amount of c-FLIPL. Both lipid-based and magnetic nanoparticle-mediated gene transfection methods successfully applied. Caspase-8 apoptosis pathway was activated on transfected cells. Magnetic nanoparticle-mediated gene transfer is a successful non-viral method for transfection, and it does not affect the expression of other cell proteins, such as beta actin and lamin-B1. The raised c-FLIPL concentration in cytosol inhibits apoptosis. However, transfection of CD95-GFP-tagged pDNA significantly increases apoptosis by activating caspase-8 pathway. FasL interaction indicated a slight increase of apoptosis in the transfected cells. The method and pDNA applied in this study have potentials to be used in gene therapy for breast cancer.

The 3-methyl-4-nitrophenol (PNMC) compromises airway epithelial barrier function.

BACKGROUND AND AIMS: It is recognized that the air pollution is associated with the pathogenesis of airway diseases. This study aims to elucidate the role of the 3-methyl-4-nitrophenol (PNMC), one of the components of diesel-exhaust particles, in compromising the airway epithelial barrier integrity. METHODS: A549 cells, an airway epithelial cell line, were cultured to monolayers to be used as an in vitro epithelial barrier model. BALB/c mice were treated with nasal drops containing PNMC to test the effects of PNMC on alternating the airway epithelial barrier functions. RESULTS: Exposure of mice to PNMC induced nasal epithelial cell apoptosis and increased the permeability of the nasal epithelial barrier. PNMC increased casp8 and casp3 activities in nasal epithelial cells. Exposure to PNMC up regulated Fas and FasL expression in airway epithelial cells. Inhibition of caspase abolished the PNMC-induced airway epithelial barrier dysfunction. CONCLUSION: Exposure of airway mucosa to PNMC induces epithelial cell apoptosis and compromises the epithelial barrier function, which can be prevented by the inhibition of caspases.

Immunohistochemical Analysis of the Extrinsic Apoptosis Process in the Non-Neoplastic and Neoplastic Prostate.

OBJECTIVE: Deviations in the apoptotic process have been demonstrated in prostate carcinogenesis. We aimed to evaluate especially the process of extrinsic apoptosis in the spectrum of neoplastic lesions of the prostate epithelium so as to reveal the variations in the apoptotic process. MATERIAL AND METHOD: The study included 20 benign prostatic hyperplasia, 8 high-grade prostatic intraepithelial neoplasia and 82 prostatic carcinoma patients. Immunohistochemistry was performed on sections obtained from materials of suprapubic prostatectomy, tru-cut biopsy, transurethral resection and radical prostatectomy. While Fas and FasL were evaluated in glandular and stromal areas, DcR1 and FLIP were evaluated in only glandular areas. Intensity and extent of immunostaining for Fas and FasL antibodies were separately scored and both scores were summarized. The total score of ≥ 4 both for Fas and FasL, expressions of FLIP and DcR1determined in more than 5% of glandular areas were accepted as positive. RESULTS: Glandular FasL positivity was observed in 63.8 and 20% of the cases with prostatic carcinoma and benign prostatic hyperplasia, respectively (p=0.001). The loss of stromal Fas expression in PCa was obvious (p < 0.001). FLIP positivity was more frequently seen in high-grade prostatic intraepithelial neoplasia and PCa. CONCLUSION: In prostatic carcinoma, decreased stromal Fas expression, contrary to higher glandular FasL positivity, supports the assertion that sensitivity of epithelial and stromal cells to apoptosis and their protective pathways against apoptosis undergo alterations. Increased FLIP expressions in high-grade prostatic intraepithelial neoplasia and prostatic carcinoma can also be interpreted accordingly.

Methotrexate Induces Apoptosis in Organ-Cultured Nasal Polyps Via the Fas Pathway.

OBJECTIVE: Methotrexate (MTX) is very effective when used to treat chronic inflammatory diseases, and also induces apoptosis in nasal polyps (NPs). Increasing evidence suggests that Fas-Fas ligand (FasL) interactions activate multiple pathways involved in the regulation of immune and inflammatory cell functions. The aim of the present study was to identify pathways activated by Fas signaling when NPs were treated with MTX. METHODS: Nasal polyps tissues were cultured using an air-liquid interface organ culture method. Cultures were maintained in the absence or presence of MTX (10 or 100 µM) for 24 hours. The authors used the reverse transcription-polymerase chain reaction method and Western blotting to identify pathways activated by Fas when NPs were treated with MTX. RESULTS: The Fas mRNA expression ratio was unchanged upon MTX treatment, but the FasL mRNA expression ratio was significantly higher in MTX-treated than nontreated polyps. In addition, the expression levels of the Fas and FasL proteins were significantly higher in polyps treated with both 10 and 100 µM MTX compared with nontreated polyps. CONCLUSIONS: Methotrexate induces apoptosis in NPs via the Fas pathway. Future studies should explore the topical use of MTX for NP control. Methotrexate may be a useful alternative steroid-sparing agent for the treatment of NPs.

Liver receptor homolog-1 (NR5a2) regulates CD95/Fas ligand transcription and associated T-cell effector functions.

CD95/Fas ligand (FasL) is a cell death-promoting member of the tumor necrosis factor family with important functions in the regulation of T-cell homeostasis and cytotoxicity. In T cells, FasL expression is tightly regulated on a transcriptional level involving a complex set of different transcription factors. The orphan nuclear receptor liver receptor homolog-1 (LRH-1/NR5a2) is involved in the regulation of development, lipid metabolism and proliferation and is predominantly expressed in epithelial tissues. However, its expression in T lymphocytes has never been reported so far. Based on in silico analysis, we identified potential LRH-1 binding sites within the FASLG promoter. Here, we report that LRH-1 is expressed in primary and secondary lymphatic tissues, as well as in CD4+ and CD8+ T cells. LRH-1 directly binds to its binding sites in the FASLG promoter, and thereby drives FASLG promoter activity. Mutations in the LRH-1 binding sites reduce FASLG promoter activity. Pharmacological inhibition of LRH-1 decreases activation-induced FasL mRNA expression, as well as FasL-mediated activation-induced T-cell apoptosis and T-cell cytotoxicity. In a mouse model of Concanavalin A-induced and FasL-mediated hepatitis pharmacological inhibition of LRH-1 resulted in decreased hepatic FasL expression and a significant reduction of liver damage. In summary, these data show for the first time LRH-1 expression in T cells, its role in FASLG transcription and the potential of pharmacological inhibition of LRH-1 in the treatment of FasL-mediated immunopathologies.

Down-regulation of islet amyloid polypeptide expression induces death of human annulus fibrosus cells via mitochondrial and death receptor pathways.

Islet amyloid polypeptide (IAPP) exerts its biological effects by participating in the regulation of glucose metabolism and cell apoptosis. The main goal of the present study was to investigate the expression of IAPP in degenerated intervertebral disc tissue and IAPP's modulation of extracellular matrix (ECM) catabolic and anabolic genes in human AF cells. We found that the expression of IAPP, the calcitonin receptor, and receptor activity modifying protein decreased considerably in AF cells during the progression of intervertebral disc degeneration (IDD). Meanwhile, transfection with pLV-siIAPP decreased the expression of IAPP and its receptors and reduced glucose uptake and the expression of aggrecan, Col2A1, and BG. Down-regulation of IAPP also induced a significant increase in reactive oxygen species generation in AF cells, along with a decrease in matrix metalloproteinases and an increase in the concentration of cellular Ca2+, ultimately leading to death. Further analysis revealed that siIAPP intervention promoted the release of cytochrome c from mitochondria, resulting in the activation of Caspase-3 and Caspase-9. In contrast, significantly decreased expression of Caspase-3 and Caspase-9 was observed in AF cells transfected with pLV-IAPP. The concentrations of Fas and FasL proteins were significantly decreased in AF cells transfected with PLV-IAPP, while activation of the Fas/FasL system and cell death were induced by siIAPP intervention. Mechanistically, AMPK/Akt-mTOR signaling pathways were involved. In conclusion, down-regulation of IAPP expression induces the death of human AF cells via mitochondrial and death receptor pathways, potentially offering a novel therapeutic target for the treatment of IDD.

Production of the Non-apoptotic Metalloprotease-Cleaved CD95L and Its Cytotoxic Recombinant Counterpart Designed Ig-CD95L.

The ligand of CD95, CD95L (also known as FasL or CD178), is a type II transmembrane protein that belongs to the Tumor Necrosis factor (TNF) family (Fig. 1a). This membrane-bound cytokine is mainly expressed at the surface of activated T lymphocytes and natural killer cells, where it is used as an apoptotic factor to eliminate infected and transformed cells (Strasser et al., Immunity 30:180-192, 2009).

Early growth response 3 inhibits growth of hepatocellular carcinoma cells via upregulation of Fas ligand.

Hepatocellular carcinoma (HCC) is a prevalent malignancy with aggressive biological behavior and poor prognosis. Early growth response 3 (EGR3) is a zinc finger transcription factor, and has been studied primarily in the context of neurodevelopment, autoimmunity, inflammation and angiogenesis. Accumulating evidence indicates that EGR3 is a novel suppressor gene of tumor initiation and progression in certain cancer events, but little work has been carried out in exploring the relationship between EGR3 and HCC growth. The purpose of this study was to investigate the possible effects of EGR3 on cell proliferation and apoptosis in HCC, and determine the underlying mechanisms. Here, we observed that EGR3 expression was frequently downregulated in HCC tissues and cell lines. Ectopic expression of EGR3 contributed to cell proliferation inhibition and apoptosis induction in HCC cells in vitro. Furthermore, the expression of Fas ligand (FasL) was significantly enhanced following upregulation of EGR3 in HCC cells, accompanied by an obvious increase of pro-apoptotic Bak and cell cycle inhibitor p21 expression. Based on nude mouse models, we demonstrated that ectopic expression of EGR3 markedly restricted tumor growth, and the expression of FasL was significantly increased in the xenograft tumor tissues which exhibited high EGR3 expression. We further established a co-transfection in HCC cells with EGR3 overexpression plasmid and FasL siRNA. We found that silencing of FasL gene impeded the anti-proliferative and pro-apoptotic effects, as well as the increase of Bak and p21 expression, suggesting an essential role of FasL in EGR3-mediated growth suppression in HCC cells. Collectively, in conclusion, EGR3 contributes to cell growth inhibition via upregulation of FasL in HCC.

Differential activation of CD95-mediated apoptosis related proteins in proximal and distal tubules during rat renal development.

The CD95-mediated apoptotic pathway is the best characterized of the death receptor-mediated apoptotic pathways. The present study characterized localization and expression of proteins involved in CD95-mediated apoptosis during rat renal development. Kidneys were obtained from embryonic (E) 18 and 20-day-old fetuses and postnatal (P) 1-, 3-, 5-, 7-, 14-, and 21-day-old pups. Immunohistochemical characterization revealed that CD95, FasL and cleaved caspase-3 were strongly expressed in proximal tubules and weakly expressed in distal tubules, but that expression of caspase-8 in distal tubules was stronger than that in proximal tubules. Results from terminal deoxynucleotidyl transferase dUTP nick end labeling assays showed that levels of apoptosis in proximal tubules slowly increased after E18, while those of distal tubules slowly decreased after P5. Western blotting demonstrated that expression of CD95, FasL and FADD was very weak during embryonic development, but rapidly increased at P14. Expression of cleaved caspase-3 was maintained at high levels after P1, while caspase-8 expression gradually reached a peak at P7. Results from this study reveal that the CD95-mediated apoptotic pathway is a key driver of apoptosis in proximal tubules during late postnatal kidney development in rats and suggest that apoptosis in distal tubules is mediated by a different apoptotic pathway.

Expression of miR-98 in myocarditis and its influence on transcription of the FAS/FASL gene pair.

Myocarditis is a common cardiovascular disease and frequently occurs in children and teenagers. It is believed to be caused by both endogenous and exogenous factors, among which FAS/FASL gene pair-induced cell apoptosis is a major mechanism of myocardial cell injury. A previous study has detected low expression of microRNA (miR)-98 in myocarditis patients. Therefore, in this study we investigated the functional implications of miR-98 with respect to the disease. We carried out a case-control study including 50 myocarditis patients and 50 healthy individuals. Total RNA was extracted from peripheral blood plasma. Expression levels of miR-98 and the FAS/FASL gene pair were determined by real-time fluorescent quantitative polymerase chain reaction. The interaction between miR-98 and the FAS/FASL pair was visualized by dual-luciferase reporter assay. The expression of the FAS/FASL gene pair was further detected by transfecting with an miR-98 mimic or an miR-98 inhibitor. The content of miR-98 in the peripheral blood of the myocarditis patients was significantly lower than in the healthy individuals. However, the FAS/FASL genes were upregulated by 1.68-fold in the myocarditis patients. miR-98 was shown to interact with the 3'-untranslated region of the FAS/FASL gene pair. The inhibition/facilitation of miR-98 expression in myocardial cells can modulate apoptosis. miR-98 was downregulated in the peripheral blood of myocarditis patients. It may interact with the FAS/FASL gene pair to further modulate cell apoptosis.