Bcl-2 down-regulates the activity of transcription factor NF-kappaB induced upon apoptosis

Parthenolide alleviates indomethacin-induced gastric ulcer in rats via antioxidant, anti-inflammatory, and antiapoptotic activities

Parthenolide (PTL) is a sesquiterpene lactone that occurs naturally. It demonstrates a variety of beneficial effects, such as antioxidant, anti-inflammatory, and antiapoptotic properties. The study investigated the potential protective impact of PTL on indomethacin (INDO) induced stomach ulcers in rats. The rats were classified into 5 distinct categories. Group 1 served as the "control" group. Rats in the second group received a single oral dosage of INDO (50 mg kg-1). Rats in Groups three and four received 20 and 40 mg kg-1 oral PTL 1 h before INDO. Omeprazole (30 mg kg-1) was given orally to Group 5 rats 1 h before INDO. Pretreatment with PTL increased stomach pH and decreased gastric volume as well as reduced the morphological and histological changes induced by INDO. Analysis of probable pathways showed that pre-treatment with PTL successfully reduced oxidative, inflammatory, and apoptotic consequences caused by INDO. The ingestion of PTL leads to a notable increase in the levels of glutathione reduced (GSH) and the activities of superoxide dismutase (SOD) and catalase (CAT). Furthermore, PTL decreased the concentration of malondialdehyde (MDA). In contrast, it was shown that PTL increased both cyclooxygenase-1 (COX-1) and prostaglandin E2 (PGE2). PTL shows a significant decrease in the expression of interleukin-1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α), inducible nitric oxide synthase (iNOS), and nuclear factor kappa B (NF-κB). PTL therapy resulted in a decrease in Bcl-2-associated X protein (Bax) levels and an increase in B-cell lymphoma 2 (Bcl2) levels. In conclusion, PTL offers gastroprotection by its antioxidant, anti-inflammatory, and anti-apoptotic qualities.

Glutathione regulates CIA-activated splenic-lymphocytes via NF-κB/MMP-9 and MAPK/PCNA pathways manipulating immune response

Reduced glutathione (GSH) is an antioxidant involved in redox homeostasis, and recently regarded as an inducer of Reductive stress. Its immune-regulatory effects on lymphocytes have not been extensively studied. This study is based on the finding that much increased GSH level in collagen-induced arthritis (CIA) rat spleen, and aimed to investigate the effects of GSH (0, 1, 10, 100 mM) on normal and immune-stimulated spleen lymphocytes respectively. The elevated GSH level is associated with the increased levels of inflammatory factors; especially the increased DPP1 activity indicated immune-granulocytes activation in CIA rat spleen. Exogenous GSH had different influences on normal and CIA lymphocytes, affecting intracellular levels of GSH, Glutathione-S-transferases (GSTs) and Reactive oxygen species (ROS); as well as the expressions of NF-κB, MMP-9, Bcl-2, GST, P38, PCNA and TLR4. The increased extracellular GSH level disturbed redox homeostasis and induces reductive stress to spleen lymphocytes, which decreased intracellular GSH concentration and influenced the MAPK/PCNA and NF-κB/MMP-9 signaling pathways, as well as cell cycles respectively, leading to cell senescence/ferroptosis/apoptosis. This study also revealed the multiple faces of GSH in regulating spleen lymphocytes, which depended on its levels in tissue or in cells, and the activation status of lymphocytes. These findings indicate the immune-regulatory role of GSH on spleen-lymphocytes, and the high level GSH in CIA rat spleens may contribute to CIA development.

Protective effect of Cordyceps sinensis against diabetic kidney disease through promoting proliferation and inhibiting apoptosis of renal proximal tubular cells

BACKGROUND

Diabetic kidney disease (DKD) has mainly been considered as a glomerular disease. Our previous study showed that the progression of DKD was highly correlated with the dysfunction of renal proximal tubular cells. Fermented Cordyceps sinensis (CS), a substitute for natural CS, is a prominent herb widely used in China, and has exhibited excellent efficacy on DKD. However, the underlying mechanisms remain poorly understood.

METHODS

The database analysis was used to identify the main therapeutic targets and pathways of CS involved in DKD treatment. Next, the protective effects of fermented CS on high glucose (HG, 30 mM) induced HK-2 cell injury was validated through cell proliferation and apoptosis assay, including CCK-8, EdU and TUNEL. Finally, quantitative real‑time PCR (qRT-PCR) and western blotting were used to verify key target genes.

RESULTS

Our results revealed that 9 main targets (RELA, JNK1, PTEN, VEGFA, EGF, ERK2, CASP3, AKT1, MMP9) were recognized as key therapeutic targets with excellent binding affinity screened by database analysis and molecular docking. The biological processes were identified by Gene Ontology (GO) enrichment, which appeared mainly involved in the positive regulation of cell proliferation as well as the negative regulation of apoptosis. The verification experiments in vitro revealed that fermented CS significantly attenuated the HG-induced cytotoxicity and apoptosis, and promoted the proliferation of HK-2 cells. Moreover, fermented CS significantly downregulated the expressions of Bax, Caspase-3, VEGFA, P-AKT and P-ERK, and upregulated the expression of PTEN compared with that of HG group.

CONCLUSION

Our results demonstrate that the fermented CS has nephroprotective effects significantly, which functions via promoting proliferation and inhibiting apoptosis of renal proximal tubular cells, likely by targeting Caspase-3, Bax, VEGFA and PTEN. Furthermore, AKT and ERK signaling pathway may be the critical mechanisms underlying the efficacy of fermented CS in DKD treatment.

Dietary chlorella (Chlorella vulgaris) supplementation effectively improves body color, alleviates muscle inflammation and inhibits apoptosis in largemouth bass (Micropterus salmoides)

Muscle quality, antioxidant status, and inflammatory and apoptotic molecule expression were investigated in juvenile largemouth bass fed five levels of Chlorella for 60 days. The results showed that muscle quality can be improved by increasing the muscle crude protein content, muscle and skin brightness value (L*), redness value (a*) and yellowness value (b*) in Chlorella-supplemented diets without affecting the growth and muscle fiber development of fish. Chlorella supplementation did not cause oxidative stress in muscle, but optimal Chlorella administration alleviated the muscle inflammatory response by downregulating the nuclear factor κB (NF-κB)-mediated proinflammatory factors such as interleukin 1β (IL-1β) and interleukin 8 (IL-8). Moreover, anti-apoptotic effects were induced by upregulation of anti-apoptotic genes, such as b cell lymphoma-2 (bcl-2) and myeloid cell leukemia-1 (mcl-1), and downregulation of pro-apoptotic genes, including bcl2-associated x (bax) and caspase3. In conclusion, Chlorella improved muscle quality, alleviated muscle inflammation and resisted muscle apoptosis.

Overexpression of the PPAR-γ protein in primary Ta/T1 non-muscle-invasive urothelial carcinoma

Peroxisome proliferator-activated receptor-γ (PPAR-γ) is a well-known nuclear receptor that is activated in the nucleus to regulate several transcription factors. Its expression patterns have been examined in various types of cancer. The present study investigated the expression patterns of PPAR-γ in non-muscle-invasive urothelial carcinoma. The expression rates of PPAR-γ, p53 and Ki-67 were compared to determine whether PPAR-γ may be considered as an immunobiomarker for bladder cancer. The intensity and extent of PPAR-γ expression were evaluated in 79 cases of non-muscle-invasive urothelial carcinoma (30 cases of papillary carcinoma low-grade, 30 cases of high-grade and 19 cases of carcinoma in situ) and 30 non-malignant cases. The nuclear overexpression of PPAR-γ was frequently observed in non-muscle-invasive urothelial carcinoma (63/79 cases) but was rarely detected in non-malignant cases (2/30 cases). The histological proliferation types of non-muscle-invasive urothelial carcinoma revealed that PPAR-γ was more frequently overexpressed in papillary carcinoma (54/60 cases) than in carcinoma in situ (9/19 cases). Immunohistochemical staining demonstrated that PPAR-γ was more useful as an immunobiomarker than p53 or Ki-67 (diagnostic odds ratios; 55.13, 16.82 and 11.13, respectively). In summary, this study demonstrated that the expression patterns of PPAR-γ were associated with histological proliferation type and that PPAR-γ was expressed in the nuclei of papillary carcinoma cells. These findings suggested that immunohistochemical staining for PPAR-γ may be used to comprehensively detect non-muscle-invasive urothelial carcinoma.

Regional infusion of a class C TLR9 agonist enhances liver tumor microenvironment reprogramming and MDSC reduction to improve responsiveness to systemic checkpoint inhibition

Myeloid-derived suppressor cells (MDSCs) expand in response to malignancy and suppress responsiveness to immunotherapy, including checkpoint inhibitors (CPIs). Within the liver, MDSCs have unique immunosuppressive features. While TLR9 agonists have shown promising activities in enhancing CPI responsiveness in superficial tumors amenable to direct needle injection, clinical success for liver tumors with TLR9 agonists has been limited by delivery challenges. Here, we report that regional intravascular infusion of ODN2395 into mice with liver metastasis (LM) partially eliminated liver MDSCs and reprogrammed residual MDSC. TLR9 agonist regional infusion also induced an increase in the M1/M2 macrophage ratio. Enhanced TLR9 signaling was demonstrated by an increased activation of in NFκB (pP65) and production of IL6 compared with systemic infusion. Further, PBMC-derived human MDSCs express TLR9, and treatment with class C TLR9 agonists (ODN2395 and SD101) reduced the expansion of MDSC population. TLR9 stimulation induced MDSC apoptosis and increased the M1/M2 macrophage ratio. Regional TLR9 agonist infusion along with systemic anti-PD-1 therapy improved control of LM. With effective delivery, TLR9 agonists have the potential to favorably reprogram the liver TME through reduction of MDSCs and favorable macrophage polarization, which may improve responsiveness to systemic CPI therapy.

NF-κB pathway play a role in SCD1 deficiency-induced ceramide de novo synthesis

Stearoyl-CoA-desaturase 1 (SCD1) deficiency mediates apoptosis in colorectal cancer cells by promoting ceramide de novo synthesis. The mechanisms underlying the cross-talk between SCD1 and ceramide synthesis have not been explored. We treated colorectal cancer cells with an SCD1 inhibitor and examined the effects on gene expression, cell growth, and cellular lipid contents. The main effect of SCD1 inhibition on the fatty acid contents of colorectal cancer cells was a decrease in monounsaturated fatty acids (MUFAs). RNA sequencing (RNA-seq) showed that the most intense alteration of gene expression after SCD1 inhibition occurred in the NF-κB signaling pathway. Further experiments revealed that SCD1 inhibition resulted in increased levels of phosphorylated NF-κB p65 and increased nuclear translocation of NF-κB p65. Treatment with an NF-κB inhibitor eliminated several effects of SCD1 inhibition, mainly including overexpression of serine palmitoyltransferase1 (SPT1), elevation of dihydroceramide contents, and suppression of cell growth. Furthermore, treatment with supplemental oleate counteracted the SCD1-induced NF-κB activation and downstream effects. In summary, our data demonstrate that the NF-κB pathway plays a role in SCD1 deficiency-induced ceramide de novo synthesis in colorectal cancer cells, and that reduced MUFA levels contribute to the course.

CD137 Signaling Promotes Endothelial Apoptosis by Inhibiting Nrf2 Pathway, and Upregulating NF-κB Pathway

Background

Endothelial dysfunction and apoptosis resulting from oxidative stress can lead to the development of atherosclerosis. Our group has previously showed that CD137 signaling contributes to the progression of atherosclerosis and the vulnerability of plaques. The aim of this study is to investigate the effects of CD137 signaling in atherosclerosis on endothelial cells (ECs) apoptosis and to explore the underlying mechanisms.

Methods

Serum samples were collected from 11 patients with acute myocardial infarction and 4 controls. Peritoneal injection of agonist-CD137 recombinant protein in ApoE^−/− mice was used to determine whether CD137 signaling can promote apoptosis in vivo, and human umbilical vein endothelial cells treated with agonist-CD137 recombinant protein, M5580 (a Nrf2 pathway agonist) and CAPE (a NF-κB pathway inhibitor) were used to explore the effect of Nrf2 and NF-κB pathway in CD137 signaling-induced ECs apoptosis in vitro.

Results

ELISA showed that Bcl-2 in the serum of AMI patients was lower than that of the control group, while TNF-α and sCD137 were higher than that of the control group. Confocal microscopy and Western blot analysis showed that the nuclear translocation of Nrf2 in the agonist-CD137 group was significantly inhibited, and the expression of its downstream antioxidant enzymes was also decreased when compared with control. Immunofluorescence and Western blot results showed that the nuclear translocation of NF-κB in the agonist-CD137 group was enhanced, and ELISA results showed that the secretion of proinflammatory cytokines in the agonist-CD137 group was increased. Immunofluorescence results revealed that ROS production in the agonist-CD137 group was higher than that in control, M5580 (a Nrf2 pathway agonist) and CAPE (a NF-κB pathway inhibitor) groups. In vitro studies using HUVECs and in vivo studies using high-fat-fed ApoE^−/− mice showed that the number of apoptotic endothelial cells was the highest in the agonist-CD137 group. By contrast, both M5580 and CAPE treatments were able to reduce CD137 induced ECs apoptosis.

Conclusions

Our results showed that CD137 signaling promotes ECs apoptosis through prooxidative and proinflammatory mechanisms, mediated by Nrf2 and NF-κB pathways, respectively.

ADAM12 silencing promotes cellular apoptosis by activating autophagy in choriocarcinoma cells

ADAM metallopeptidase domain 12 (ADAM12) has been demonstrated to mediate cell proliferation and apoptosis resistance in several types of cancer cells. However, the effect of ADAM12 silencing on the proliferation and apoptosis of choriocarcinoma cells remains unknown. The present study revealed that ADAM12 silencing significantly inhibited cellular activity and proliferation in the human choriocarcinoma JEG3 cell line and increased the rate of apoptosis. In addition, ADAM12 silencing significantly increased the expression levels of the autophagy proteins microtubule-associated protein-light-chain 3 (LC3B) and autophagy related 5 (ATG5) and the fluorescence density of LC3B in JEG-3 cells. However, the suppression of autophagy by 3-methyladenine could block ADAM12 silencing-induced cellular apoptosis. ADAM12 silencing reduced the levels of the inflammatory factors interleukin-1β, interferon-γ and TNF-α, and inactivated nuclear p65-NF-κB and p-mTOR in JEG-3 cells. The downregulation of p-mTOR expression by ADAM12 silencing was rescued in 3-methyladenine-treated JEG-3 cells, indicating that mTOR might participate in the autophagy-mediated pro-apoptotic effect of ADAM12 silencing. In conclusion, ADAM12 silencing promoted cellular apoptosis in human choriocarcinoma JEG3 cells, which might be associated with autophagy and the mTOR response. These findings indicate that ADAM12 silencing might be a potential novel therapeutic target for choriocarcinoma.

Neferine-induced apoptosis is dependent on the suppression of Bcl-2 expression via downregulation of p65 in renal cancer cells

Neferine is an alkaloid extracted from a seed embryo of Nelumbo nucifera and has recently been shown to have anticancer effects in various human cancer cell lines. However, the detailed molecular mechanism of neferine-induced apoptosis has not been elucidated in renal cancer cells. In the present study, we observed that neferine induced inhibition of cell proliferation and apoptosis in Caki-1 cells in a dose-dependent manner by using MT assay and flow cytometry and that neferine-mediated apoptosis was attenuated by pretreatment with N-benzyloxycarbony-Val-Ala-Asp (O-methyl)-fluoromethyketone, a pan-caspase inhibitor. Treatments with neferine dose-dependently downregulated B cell lymphoma-2 (Bcl-2) expression at the transcriptional level determined by reverse transcriptase-polymerase chain reaction. The forced expression of Bcl-2 and p65 attenuated the neferine-mediated apoptosis in Caki-1 cells. In addition, neferine induced apoptosis by downregulating Bcl-2 and p65 expression in the other two kidney cancer cell lines determined by flow cytometry and western blot analysis. Finally, we observed that treatment with neferine induced apoptosis by inhibiting the NF-κB pathway through caspase-mediated cleavage of the p65 protein by western blot analysis. Collectively, this study demonstrated that neferine-induced apoptosis is mediated by the downregulation of Bcl-2 expression via repression of the NF-κB pathway in renal cancer cells.

Activation and Expression of Peroxisome Proliferator-Activated Receptor Alpha Are Associated with Tumorigenesis in Colorectal Carcinoma

Peroxisome proliferator-activated receptor alpha (PPAR-α) belongs to the PPAR family and plays a critical role in inhibiting cell proliferation and tumorigenesis in various tumors. However, the role of PPAR-α in colorectal tumorigenesis is unclear. In the present study, we found that fenofibrate, a PPAR-α agonist, significantly inhibited cell proliferation and induced apoptosis in colorectal carcinoma cells. In addition, PPAR-α was expressed in the nucleus of colorectal carcinoma cells, and the expression of nuclear PPAR-α increased in colorectal carcinoma tissue compared with that of normal epithelium tissue (P<0.01). The correlation between the expression of nuclear PPAR-α and clinicopathological factors was evaluated in human colorectal carcinoma tissues, and the nuclear expression of PPAR-α was significantly higher in well-to-moderately differentiated adenocarcinoma than in mucinous adenocarcinoma (P<0.05). These findings indicate that activation of PPAR-α may be involved in anticancer effects in colorectal carcinomas, and nuclear expression of PPAR-α may be a therapeutic target for colorectal adenocarcinoma treatment.

TRAF3 Is Required for NF-κB Pathway Activation Mediated by HTLV Tax Proteins

Human T-cell leukemia viruses type 1 (HTLV-1) and type 2 (HTLV-2) share a common genome organization and expression strategy but have distinct pathological properties. HTLV-1 is the etiological agent of Adult T-cell Leukemia (ATL) and of HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP), whereas HTLV-2 does not cause hematological disorders and is only sporadically associated with cases of subacute myelopathy. Both HTLV genomes encode two regulatory proteins that play a pivotal role in pathogenesis: the transactivating Tax-1 and Tax-2 proteins and the antisense proteins HBZ and APH-2, respectively. We recently reported that Tax-1 and Tax-2 form complexes with the TNF-receptor associated factor 3, TRAF3, a negative regulator of the non-canonical NF-κB pathway. The NF-κB pathway is constitutively activated by the Tax proteins, whereas it is inhibited by HBZ and APH-2. The antagonistic effects of Tax and antisense proteins on NF-κB activation have not yet been fully clarified. Here, we investigated the effect of TRAF3 interaction with HTLV regulatory proteins and in particular its consequence on the subcellular distribution of the effector p65/RelA protein. We demonstrated that Tax-1 and Tax-2 efficiency on NF-κB activation is impaired in TRAF3 deficient cells obtained by CRISPR/Cas9 editing. We also found that APH-2 is more effective than HBZ in preventing Tax-dependent NF-κB activation. We further observed that TRAF3 co-localizes with Tax-2 and APH-2 in cytoplasmic complexes together with NF-κB essential modulator NEMO and TAB2, differently from HBZ and TRAF3. These results contribute to untangle the mechanism of NF-κB inhibition by HBZ and APH-2, highlighting the different role of the HTLV-1 and HTLV-2 regulatory proteins in the NF-κB activation.

The Contribution of Fluoride to the Pathogenesis of Eye Diseases: Molecular Mechanisms and Implications for Public Health

This study provides diverse lines of evidence demonstrating that fluoride (F) exposure contributes to degenerative eye diseases by stimulating or inhibiting biological pathways associated with the pathogenesis of cataract, age-related macular degeneration and glaucoma. As elucidated in this study, F exerts this effect by inhibiting enolase, τ-crystallin, Hsp40, Na⁺, K⁺-ATPase, Nrf2, γ -GCS, HO-1 Bcl-2, FoxO1, SOD, PON-1 and glutathione activity, and upregulating NF-κB, IL-6, AGEs, HsP27 and Hsp70 expression. Moreover, F exposure leads to enhanced oxidative stress and impaired antioxidant activity. Based on the evidence presented in this study, it can be concluded that F exposure may be added to the list of identifiable risk factors associated with pathogenesis of degenerative eye diseases. The broader impact of these findings suggests that reducing F intake may lead to an overall reduction in the modifiable risk factors associated with degenerative eye diseases. Further studies are required to examine this association and determine differences in prevalence rates amongst fluoridated and non-fluoridated communities, taking into consideration other dietary sources of F such as tea. Finally, the findings of this study elucidate molecular pathways associated with F exposure that may suggest a possible association between F exposure and other inflammatory diseases. Further studies are also warranted to examine these associations.

Cytoplasmic RAP1 mediates cisplatin resistance of non-small cell lung cancer

Cytotoxic chemotherapy agents (e.g., cisplatin) are the first-line drugs to treat non-small cell lung cancer (NSCLC) but NSCLC develops resistance to the agent, limiting therapeutic efficacy. Despite many approaches to identifying the underlying mechanism for cisplatin resistance, there remains a lack of effective targets in the population that resist cisplatin treatment. In this study, we sought to investigate the role of cytoplasmic RAP1, a previously identified positive regulator of NF-κB signaling, in the development of cisplatin resistance in NSCLC cells. We found that the expression of cytoplasmic RAP1 was significantly higher in high-grade NSCLC tissues than in low-grade NSCLC; compared with a normal pulmonary epithelial cell line, the A549 NSCLC cells exhibited more cytoplasmic RAP1 expression as well as increased NF-κB activity; cisplatin treatment resulted in a further increase of cytoplasmic RAP1 in A549 cells; overexpression of RAP1 desensitized the A549 cells to cisplatin, and conversely, RAP1 depletion in the NSCLC cells reduced their proliferation and increased their sensitivity to cisplatin, indicating that RAP1 is required for cell growth and has a key mediating role in the development of cisplatin resistance in NSCLC cells. The RAP1-mediated cisplatin resistance was associated with the activation of NF-κB signaling and the upregulation of the antiapoptosis factor BCL-2. Intriguingly, in the small portion of RAP1-depleted cells that survived cisplatin treatment, no induction of NF-κB activity and BCL-2 expression was observed. Furthermore, in established cisplatin-resistant A549 cells, RAP1 depletion caused BCL2 depletion, caspase activation and dramatic lethality to the cells. Hence, our results demonstrate that the cytoplasmic RAP1–NF-κB–BCL2 axis represents a key pathway to cisplatin resistance in NSCLC cells, identifying RAP1 as a marker and a potential therapeutic target for cisplatin resistance of NSCLC.

Activation and cleavage of SASH1 by caspase-3 mediates an apoptotic response

Apoptosis is a highly regulated cellular process that functions to remove undesired cells from multicellular organisms. This pathway is often disrupted in cancer, providing tumours with a mechanism to avoid cell death and promote growth and survival. The putative tumour suppressor, SASH1 (SAM and SH3 domain containing protein 1), has been previously implicated in the regulation of apoptosis; however, the molecular role of SASH1 in this process is still unclear. In this study, we demonstrate that SASH1 is cleaved by caspase-3 following UVC-induced apoptosis. Proteolysis of SASH1 enables the C-terminal fragment to translocate from the cytoplasm to the nucleus where it associates with chromatin. The overexpression of wild-type SASH1 or a cleaved form of SASH1 representing amino acids 231-1247 leads to an increase in apoptosis. Conversely, mutation of the SASH1 cleavage site inhibits nuclear translocation and prevents the initiation of apoptosis. SASH1 cleavage is also required for the efficient translocation of the transcription factor nuclear factor-κB (NF-κB) to the nucleus. The use of the NF-κB inhibitor DHMEQ demonstrated that the effect of SASH1 on apoptosis was dependent on NF-κB, indicating a codependence between SASH1 and NF-κB for this process.

4-Chlorbenzoyl Berbamine, a Novel Derivative of the Natural Product Berbamine, Potently Inhibits the Growth of Human Myeloma Cells by Modulating the NF-κB and JNK Signalling Pathways

Multiple myeloma (MM) remains incurable despite the development and the use of new agents. In our studies, we found that 4-chlorbenzoyl berbamine (BBMD9), a novel synthetic derivative of berbamine, inhibited the proliferation of MM cells in dose- and time-dependent manners. Flow cytometric (FCM) analysis revealed that MM cells were arrested in the G1 phase and that apoptotic cells increased in a time-dependent manner. Moreover, the BBMD9 treatment downregulated IKKα and IKKβ, inhibited p-IκBα, and blocked p65 nuclear localization. Consistently, NF-κB downstream targets, such as cyclinD1 and survivin, were also reduced. In addition, BBMD9 phosphorylated the activity of JNK and c-Jun.

Hepatocellular carcinoma redirects to ketolysis for progression under nutrition deprivation stress

Cancer cells are known for their capacity to rewire metabolic pathways to support survival and proliferation under various stress conditions. Ketone bodies, though produced in the liver, are not consumed in normal adult liver cells. We find here that ketone catabolism or ketolysis is re-activated in hepatocellular carcinoma (HCC) cells under nutrition deprivation conditions. Mechanistically, 3-oxoacid CoA-transferase 1 (OXCT1), a rate-limiting ketolytic enzyme whose expression is suppressed in normal adult liver tissues, is re-induced by serum starvation-triggered mTORC2-AKT-SP1 signaling in HCC cells. Moreover, we observe that enhanced ketolysis in HCC is critical for repression of AMPK activation and protects HCC cells from excessive autophagy, thereby enhancing tumor growth. Importantly, analysis of clinical HCC samples reveals that increased OXCT1 expression predicts higher patient mortality. Taken together, we uncover here a novel metabolic adaptation by which nutrition-deprived HCC cells employ ketone bodies for energy supply and cancer progression.

Relationship between Reduced BCL-2 Expression in Circulating Mononuclear Cells and Early Nephropathy in Type 1 Diabetes

Microalbuminuria is the earliest clinical evidence of diabetic nephropathy, but the mechanisms linking hyperglycemia and kidney complications are not clear. The aim of this study was to evaluate whether enhanced oxidative stress in patients with microalbuminuria can contribute to diabetic nephropathy development through downregulation of the antiapoptotic gene Bcl-2 that promotes in turn a pro-inflammatory status. We studied 30 patients with type 1 diabetes (15 with and 15 without microalbuminuria) compared to 15 matched healthy controls. Plasma oxidant status, and expression of Bcl-2, activated NF-kB, inducible Nitric Oxide synthase (iNOS), and monocyte chemoattractant protein (MCP)-1 in circulating monocytes were evaluated at baseline and after 8-week oral vitamin E treatment (600 mg b.i.d.). Bcl-2 expression was significantly reduced in microalbuminuric diabetic patients as a consequence of increased oxidant burden secondary to persistent hyperglycemia. Bcl-2 down-regulation was associated with enhanced expression of NF-kB, iNOS and MCP-1, and showed a strong correlation with the albumin excretion rate. Low Bcl-2 expression and high inflammatory status were normalized by vitamin E both in vivo and in vitro. Our study showed that Bcl-2 down-regulation in diabetic patients with poor glycemic control results in the activation of the NF-kB pathway leading to the development of nephropathy. Vitamin E might provide a novel form of therapy for prevention of nephropathy in diabetic patients in which an acceptable glycemic control is difficult to achieve despite insulin therapy.

Transcription Factors Expressed in Mouse Cochlear Inner and Outer Hair Cells

Regulation of gene expression is essential to determining the functional complexity and morphological diversity seen among different cells. Transcriptional regulation is a crucial step in gene expression regulation because the genetic information is directly read from DNA by sequence-specific transcription factors (TFs). Although several mouse TF databases created from genome sequences and transcriptomes are available, a cell type-specific TF database from any normal cell populations is still lacking. We identify cell type-specific TF genes expressed in cochlear inner hair cells (IHCs) and outer hair cells (OHCs) using hair cell-specific transcriptomes from adult mice. IHCs and OHCs are the two types of sensory receptor cells in the mammalian cochlea. We show that 1,563 and 1,616 TF genes are respectively expressed in IHCs and OHCs among 2,230 putative mouse TF genes. While 1,536 are commonly expressed in both populations, 73 genes are differentially expressed (with at least a twofold difference) in IHCs and 13 are differentially expressed in OHCs. Our datasets represent the first cell type-specific TF databases for two populations of sensory receptor cells and are key informational resources for understanding the molecular mechanism underlying the biological properties and phenotypical differences of these cells.

Topological control of nitric oxide secretion by tantalum oxide nanodot arrays

BACKGROUND

Nitric oxide (NO) plays a very important role in the cardiovascular system as a major secondary messenger in signaling pathway. Its concentration regulates most of the important physiological indexes including the systemic blood pressure, blood flow, regional vascular tone and other cardiac functions. The effect of nanotopography on the NO secretion in cardiomyocytes has not been elucidated before. In this study, we report how the nanotopography can modulate the secretion profile of NO and attempt to elucidate the genetic pathways responsible for the same by using Tantalum Oxide nanodot arrays ranging from 10 to 200 nm. A series of nanodot arrays were fabricated with dot diameter ranging from 10 to 200 nm. Temporal NO release of cardiomyocytes was quantified when grown on different surfaces. Quantitative RT-PCR and Western blot were performed to verify the genetic pathways of NO release.

RESULTS

After hours 24 of cell seeding, NO release was slowly enhanced by the increase of dot diameter from 10 nm up to 50 nm, mildly enhanced to a medium level at 100 nm, and increase rapidly to a high level at 200 nm. The temporal enhancement of NO release dropped dramatically on day 3. On day 5, a topology-dependent profile was established that maximized at 50 nm and dropped to control level at 200 nm. The NO releasing profile was closely associated with the expression patterns of genes associated with Endothelial nitric oxide synthase (eNOS) pathway [GPCR, PI3K, Akt, Bad, Bcl-2, NFκB(p65), eNOS], but less associated with Inducible nitric oxide synthase (iNOS) pathway (TNF-α, ILK, Akt, IκBα, NFκB, iNOS). Western blotting of Akt, eNOS, iNOS, and NFκB further validated that eNOS pathway was modulated by nanotopology.

CONCLUSIONS

Based on the findings of the present study, 50, 100 nm can serve as the suitable nanotopography patterns for cardiac implant surface design. These two nanodot arrays promote NO secretion and can also promote the vascular smooth muscle relaxation. The results of this study can improve the heart stent design in the medical treatments.

Canonical transient receptor potential 3 channels activate NF-κB to mediate allergic airway disease via PKC-α/IκB-α and calcineurin/IκB-β pathways

The purpose of this study was to determine the role of canonical transient receptor potential 3 (TRPC3) channel in allergen-induced airway disease (AIAD) and its underlying signaling mechanisms. The procedures included (1) intravenous injection of lentiviral TRPC3 channel or nonsilencing short hairpin ribonucleic acid (shRNA) to make the channel knockdown (KD) or control mice, (2) allergen sensitization/challenge to induce AIAD, (3) patch-clamp recording and Ca(2+) imaging to examine the channel activity, and (4) gene manipulations and other methods to determine the underlying signaling mechanisms. The findings are that (1) intravenous or intranasal delivery of TRPC3 channel lentiviral shRNAs or blocker 1-[4-[(2,3,3-trichloro-1-oxo-2-propen-1-yl)amino]phenyl]-5-(trifluoromethyl)-1H-pyrazole-4-carboxylic acid prevents AIAD in mice, (2) TRPC3 channel KD and overexpression, respectively, blocks and augments protein kinase C-α/nuclear factor of κ light polypeptide gene enhancer in B-cell inhibitor-α (PKC-α/IκB-α)-mediated or calcineurin/IκB-β-dependent, NF-κB-dependent allergen-induced airway smooth muscle cell (ASMC) hyperproliferation and cyclin D1 (an important cell proliferation molecule) induction, and (3) the changes of the major molecules of the PKC-α/IκBα- and calcineurin/IκB-β-dependent NF-κB signaling pathways are also observed in asthmatic human ASMCs. The conclusions are that TRPC3 channels plays an essential role in AIAD via the PKC-α/IκB-α- and calcineurin/IκB-β-dependent NF-κB signaling pathways, and lentiviral shRNA or inhibitor of TRPC3 channels may become novel and effective treatments for AIAD.

Dose-dependent biphasic leptin-induced proliferation is caused by non-specific IL-6/NF-κB pathway activation in human myometrial cells

BACKGROUND AND PURPOSE

Leptin, an adipokine synthesized by the placenta during pregnancy, has been proposed for the management of preterm labour (PTL), as it is able to prevent in vitro uterine contractility and remodelling associated with labour onset. Another common feature of labour onset is the phenotypic switch of myometrial smooth muscle cells from a proliferative to a hypertrophic state. As proliferative effects have been demonstrated for leptin in other tissues, we aimed to investigate its ability to induce myometrial proliferation and thus to maintain uterine quiescence.

EXPERIMENTAL APPROACH

We stimulated human primary myometrial smooth muscle cells with leptin in the presence or absence of receptor antagonists or signalling pathway inhibitors.

KEY RESULTS

Leptin induced myometrial cell proliferation in a biphasic manner. At 6.25 ng · mL(-1), leptin-induced proliferation was mediated by the leptin receptor and required the early activation of ERK1/2. At a concentration above 25 ng · mL(-1), leptin induced direct non-specific stimulation of the IL-6 receptor, leading to NF-κB activation, and exerted anti-proliferative effects. However, at 50 ng · mL(-1), leptin re-induces proliferation via IL-6 receptor stimulation that requires STAT3 and delayed ERK1/2 activation.

CONCLUSIONS AND IMPLICATIONS

These data bring new insights into leptin signalling-induced myometrial proliferation and its interrelationship with the IL-6/IL-6 receptor axis. In the light of our previous work, the present study emphasizes the potential value of leptin in the pharmacological management of PTL and it also strengthens the hypothesis that leptin might be a contributory factor in the parturition-related disorders observed in obese women.

Catalase inhibition in diabetic rats potentiates DNA damage and apoptotic cell death setting the stage for cardiomyopathy

Diabetes is a risk factor for cardiovascular disease that has a multifactorial etiology, with oxidative stress as an important component. Our previous observation of a significant diabetes-related increase in rat cardiac catalase (CAT) activity suggested that CAT could play a major role in delaying the development of diabetic cardiomyopathy. Thus, in the present work, we examined the effects of the daily administration of the CAT inhibitor, 3-amino-1,2,4-triazole (1 mg/g), on the hearts of streptozotocin (STZ)-induced diabetic rats. Administration of CAT inhibitor was started from the 15th day after the last STZ treatment (40 mg/kg/5 days), and maintained until the end of the 4th or 6th weeks of diabetes. Compared to untreated diabetic rats, at the end of the observation period, CAT inhibition lowered the induced level of cardiac CAT activity to the basal level and decreased CAT protein expression, mediated through a decline in the nuclear factor erythroid-derived 2-like 2 /nuclear factor-kappa B p65 (Nrf2/NF-κB p65) subunit ratio. The perturbed antioxidant defenses resulting from CAT inhibition promoted increased H₂O₂production (P < 0.05) and lipid peroxidation (P < 0.05). Generated cytotoxic stimuli increased DNA damage (P < 0.05) and activated pro-apoptotic events, observed as a decrease (P < 0.05) in the ratio of the apoptosis regulator proteins Bcl-2/Bax, increased (P < 0.05) presence of the poly(ADP-ribose) polymerase-1 (PARP-1) 85 kDa apoptotic fragment and cytoplasmic levels of cytochrome C. These findings confirm an important function of CAT in the suppression of events leading to diabetes-promoted cardiac dysfunction and cardiomyopathy.

Beneficial effects of muscone on cardiac remodeling in a mouse model of myocardial infarction

Musk has been traditionally used in East Asia to alleviate the symptoms of angina pectoris. However, it remains unclear as to whether muscone, the main active ingredient of musk, has any beneficial effects on persistent myocardial ischemia in vivo. The aim of the present study was to investigate whether muscone can improve cardiac function and attenuate myocardial remodeling following myocardial infarction (MI) in mice. Mice were subjected to permanent ligation of the left anterior descending coronary artery to induce MI, and then randomly treated with muscone (2 mg/kg/day) or the vehicle (normal saline) for 3 weeks. Sham-operated mice were used as controls and were also administered the vehicle (normal saline). Treatment with muscone significantly improved cardiac function and exercise tolerance, as evidenced by the decrease in the left ventricular end-systolic diameter, left ventricular end-diastolic diameter, as well as an increase in the left ventricular ejection fraction, left ventricular fractional shortening and time to exhaustion during swimming. Pathological and morphological assessments indicated that treatment with muscone alleviated myocardial fibrosis, collagen deposition and improved the heart weight/body weight ratio. Muscone inhibited the inflammatory response by reducing the expression of transforming growth factor (TGF)‑β1, tumor necrosis factor (TNF)-α, interleukin (IL)-1β and nuclear factor (NF)-κB. Treatment with muscone also reduced myocardial apoptosis by enhancing Bcl-2 and suppressing Bax expression. Muscone also induced the phosphorylation of protein kinase B (Akt) and endothelial nitric oxide synthase (eNOS). Our results demonstrate that muscone ameliorates cardiac remodeling and dysfunction induced by MI by exerting anti-fibrotic, anti-inflammatory and anti-apoptotic effects in the ischemic myocardium.

Role of di-allyl disulfide, a garlic component in NF-κB mediated transient G2-M phase arrest and apoptosis in human leukemic cell-lines

Diallyl disulfide (DADS), the major organosulfur component of processed garlic is very effective in chemoprevention of several types of cancers; however, its detailed mechanism is yet to be divulged. Present study shows antiproliferative activity of DADS against human leukemic cell-lines, mainly U937. DADS induced transient G2/M phase arrest, which is evident from FACS analysis. The results revealed that a significant transcriptional induction of p21 happened in early hours of treatment, which is due to increased nuclear translocation of NF-κB and its specific binding to p21 promoter. However, in the later hours, G2/M arrest is lost leading to apoptosis via intrinsic mitochondria-mediated pathway through generation of reactive oxygen species followed by changes in mitochondrial membrane potential. Western blots indicate release of cytochrome-c, activation of caspase-3, cleavage of PARP1, and finally decrease in bcl-2 levels. In addition, inactivation of NF-κB by its inhibitor BAY 11-7085 causes early onset of apoptosis without any transient G2/M arrest. Thus, in conclusion, DADS induces reversible G2/M arrest through NF-κB mediated pathway in human leukemic cell lines, like U937, K562, and Jurkat, lacking wild type p53. However, G2/M arrest is lost owing to the incapability of the damage repair system that leads to apoptosis.

Influence of gonadotropin-releasing hormone agonist on the effect of chemotherapy upon ovarian cancer and the prevention of chemotherapy-induced ovarian damage: an experimental study with nu/nu athymic mice

BACKGROUND AND OBJECTIVE

Gonadotropin-releasing hormone (GnRH) plays an important role in the regulation of ovarian function and ovarian cancer cell growth. In this study, we determined whether administration of the GnRH agonist (GnRHa), triporelin, prior to cisplatin treatment affects cisplatin and/or prevents cisplatin-induced ovarian damage.

METHODS

nu/nu mice were injected with ovarian cancer OVCAR-3 cells intraperitoneally. After two weeks, the mice were treated with saline (control), cisplatin, GnRHa, or cisplatin plus GnRHa for four weeks. At the end of the experimental protocol, blood, tumor, ovary, and uterine tissues were resected for hematoxylin and eosin (H&E) staining, immunohistochemical analyses of Ki67, nuclear factor-κB (NF-κB), and caspase-3, transmission electron microscopy of apoptosis, or enzyme-linked immunosorbent assay (ELISA) analyses of anti-Mullerian hormone (AMH).

RESULTS

Cisplatin treatment effectively inhibited tumor growth in mice treated with human ovarian cancer cells; however the treatment also induced considerable toxicity. Immunohistochemical analyses showed that Ki67 expression was reduced in cisplatin-treated mice compared to control (P<0.05), but there was no statistically significant differences between cisplatin-treated mice and cisplatin plus GnRHa-treated mice (P>0.05), while expressions of NF-κB and caspase-3 were reduced and induced, respectively, in cisplatin-treated mice and cisplatin plus GnRHa-treated mice. Apoptosis occurred in the GnRHa, cisplatin, and cisplatin plus GnRHa-treated mice, but not in control mice. Ovaries exposed to GnRHa in both GnRHa mice and cisplatin-treated mice (combination group) had significantly more primordial and growth follicles and serum levels of AMH than those in the control mice and cisplatin-treated mice (P<0.05).

CONCLUSIONS

Administration of GnRHa to mice significantly decreased the extent of ovarian damage induced by cisplatin, but did not affect the anti-tumor activity of cisplatin.

Enhancing in vivo survival of adipose-derived stromal cells through Bcl-2 overexpression using a minicircle vector

Tissue regeneration using progenitor cell-based therapy has the potential to aid in the healing of a diverse range of pathologies, ranging from short-gut syndrome to spinal cord lesions. However, there are numerous hurdles to be overcome prior to the widespread application of these cells in the clinical setting. One of the primary barriers to effective stem cell therapy is the hostile environment that progenitor cells encounter in the clinical injury wound setting. In order to promote cellular survival, stem cell differentiation, and participation in tissue regeneration, relevant cells and delivery scaffolds must be paired with strategies to prevent cell death to ensure that these cells can survive to form de novo tissue. The Bcl-2 protein is a prosurvival member of a family of proteins that regulate the mitochondrial pathway of apoptosis. Using several strategies to overexpress the Bcl-2 protein, we demonstrated a decrease in the mediators of apoptosis in vitro and in vivo. This was shown through the use of two different clinical tissue repair models. Cells overexpressing Bcl-2 not only survived within the wound environment at a statistically significantly higher rate than control cells, but also increased tissue regeneration. Finally, we used a nonintegrating minicircle technology to achieve this in a potentially clinically applicable strategy for stem cell therapy.

Reovirus receptors, cell entry, and proapoptotic signaling

Mammalian orthoreoviruses (reoviruses) are members of the Reoviridae. Reoviruses contain 10 double-stranded (ds) RNA gene segments enclosed in two concentric protein shells, called outer capsid and core. These viruses serve as a versatile experimental system for studies of viral replication events at the virus-cell interface, including engagement of cell-surface receptors, internalization and disassembly, and activation of the innate immune response, including NF-κB-dependent cellular signaling pathways. Reoviruses also provide a model system for studies of virus-induced apoptosis and organ-specific disease in vivo.Reoviruses attach to host cells via the filamentous attachment protein, σ1. The σ1 protein of all reovirus serotypes engages junctional adhesion molecule-A (JAM-A), an integral component of intercellular tight junctions. The σ1 protein also binds to cell-surface carbohydrate, with the type of carbohydrate bound varying by serotype. Following attachment to JAM-A and carbohydrate, reovirus internalization is mediated by β1 integrins, most likely via clathrin-dependent endocytosis. In the endocytic compartment, reovirus outer-capsid protein σ3 is removed by acid-dependent cysteine proteases in most cell types. Removal of σ3 results in the exposure of a hydrophobic conformer of the viral membrane-penetration protein, μ1, which pierces the endosomal membrane and delivers transcriptionally active reovirus core particles into the cytoplasm.Reoviruses induce apoptosis in both cultured cells and infected mice. Perturbation of reovirus disassembly using inhibitors of endosomal acidification or protease activity abrogates apoptosis. The μ1-encoding M2 gene is genetically linked to strain-specific differences in apoptosis-inducing capacity, suggesting a function for μ1 in induction of death signaling. Reovirus disassembly leads to activation of transcription factor NF-κB, which modulates apoptotic signaling in numerous types of cells. Inhibition of NF-κB nuclear translocation using either pharmacologic agents or expression of transdominant forms of IκB blocks reovirus-induced apoptosis, suggesting an essential role for NF-κB activation in the death response. Multiple effector pathway s downstream of NF-κB-directed gene expression execute reovirus-induced cell death. This chapter will focus on the mechanisms by which reovirus attachment and disassembly activate NF-κB and stimulate the cellular proapoptotic machinery.

Protein kinase Cα is involved in impaired perinatal hypothyroid rat brain development

Protein kinase Cα (PKCα) has been implicated in the regulation of a variety of cellular functions, such as proliferation, differentiation, and apoptosis, in response to a diverse range of stimuli. Activated PKCα mediates oxidative stress, apoptosis, and inflammatory reaction. Thyroid hormone (TH) is essential for the proper development of the mammalian central nervous system. TH deficiency during critical periods of brain development results in permanent cognitive and neurological impairments. In the present study, we attempted to explore whether PKCα is involved in impaired brain function in developing hypothyroid rat brain. Severe perinatal hypothyroidism was obtained by administration of 30 mg/day propylthiouracil to dams. Brain PKC activity in hypothyroid pups was increased significantly in cytosol and membrane fractions. The change of membrane PKC activity was more marked than that of cytosol, and hypothyroidism led to a higher ratio of membrane PKC activity to that in cytosol, which means abnormal activation of PKC in developing hypothyroid rat brain. Thyroxine replacement partially corrected these changes. After being treated with bisindolmaleimide XI, a mainly selective inhibitor for PKCα, the hypothyroid pups showed improved place navigation test results, and further Western blot analysis showed that PKCα expression in cytosol fractions was increased in hypothyroid rat brain with or without bisindolmaleimide XI treatment, but, after treatment with bisindolmaleimide XI, PKCα content in membrane fractions decreased almost to normal. Therefore, we conclude that PKCα appears to be involved in the impaired brain development observed in perinatal hypothyroid rat brain.

Serum starvation activates NF-κB through G protein β2 subunit-mediated signal

Several cell stresses induce nuclear factor-kappaB (NF-κB) activation, which include irradiation, oxidation, and UV. Interestingly, serum-starving stress-induced NF-κB activation in COS cells, but not in COS-A717 cells. COS-A717 is a mutant cell line of COS cells that is defective of the NF-κB signaling pathway. We isolated genes with compensating activity for the NF-κB pathway and one gene encoded the G protein β2 (Gβ2). Gβ2 is one of the G protein-coupled receptor signaling effectors. In COS-A717 cells, Gβ2 expression is significantly reduced. In Gβ2 cDNA-transfected COS-A717 cells, the NF-κB activity was increased along with the recovery of Gβ2 expression. Furthermore, serum-starving stress induced the NF-κB activity in Gβ2-transfected COS-A717 cells. Consistently, the serum-starved COS cells with siRNA-reduced Gβ2 protein expression showed decreased NF-κB activity. These results indicate that Gβ2 is required for starvation-induced NF-κB activation and constitutive NF-κB activity. We propose that serum contains some molecule(s) that strongly inhibits NF-κB activation mediated through Gβ2 signaling.

Tumor necrosis factor-like weak inducer of apoptosis and its potential roles in lupus nephritis

INTRODUCTION

Tumor necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK) is a recently identified proinflammatory cytokine of the TNF superfamily that functions through binding to Fn14 receptor in target cells. TWEAK has multiple biological activities. Studies show that TWEAK plays an important role in immune inflammatory diseases. Recent work has revealed that TWEAK may play an important role in the pathogenesis of kidney damage, including in systemic lupus erythematosus (SLE), where its concentration in urine was correlated with the level of activity of lupus nephritis (LN).

OBJECTIVE

The major focus of this review is to discuss the recent studies on TWEAK and its possible role in the pathogenesis of LN, and the therapeutic potential of modulating this pathway in LN.

RESULTS AND CONCLUSION

TWEAK plays a key role in the pathogenesis of LN through activation of multiple down-signaling pathway, inducing proinflammatory cytokines and chemokines, affecting cell proliferation/apoptosis and inducing renal IgG deposition. TWEAK blockade may be a novel therapeutic approach to reducing renal damage in SLE.

NF-κB and the link between inflammation and cancer

The nuclear factor-κB (NF-κB) transcription factor family has been considered the central mediator of the inflammatory process and a key participant in innate and adaptive immune responses. Coincident with the molecular cloning of NF-κB/RelA and identification of its kinship to the v-Rel oncogene, it was anticipated that NF-κB itself would be involved in cancer development. Oncogenic activating mutations in NF-κB genes are rare and have been identified only in some lymphoid malignancies, while most NF-κB activating mutations in lymphoid malignancies occur in upstream signaling components that feed into NF-κB. NF-κB activation is also prevalent in carcinomas, in which NF-κB activation is mainly driven by inflammatory cytokines within the tumor microenvironment. Importantly, however, in all malignancies, NF-κB acts in a cell type-specific manner: activating survival genes within cancer cells and inflammation-promoting genes in components of the tumor microenvironment. Yet, the complex biological functions of NF-κB have made its therapeutic targeting a challenge.

Mountain Grown Ginseng Induces Apoptosis in HL-60 Cells and Its Mechanism Have Little Relation with TNF-α Production

The root of ginseng is one of the most popular natural tonics in Oriental countries. Ginseng grown in the wild, deep in the mountains, is known as Sansam (mountain grown ginseng, MGG). MGG belongs to Araliaceae and Panax. In this study, we investigated the effects of MGG on the cytotoxicity, induction of apoptosis and the putative pathways of its actions in human promyelocytic leukemia cells, HL-60. Using apoptosis analysis, we found that MGG is a potent inducer of apoptosis, but it has less effect on human peripheral blood mononuclear cells. Caspase-3 activation and subsequent apoptotic cell death in MGG-treated cells were partially blocked by the caspase-3 inhibitor, Z-DEVD-FMK. MGG also inhibited the caspase-8 activity. To determine whether MGG-induced apoptosis is involved in tumor necrosis factor-α (TNF-α) secretion, TNF-α secretion was quantified by enzyme-linked immunosorbent assay (ELISA) method. Unexpectedly, MGG significantly decreased the TNF-α secretion compared to the control. These results suggest that MGG-induced cytotoxicity have little relation with the secretion of TNF-α in HL-60 cells. Furthermore, MGG with rIFN-γ synergistically increased nitric oxide (NO) production in mouse peritoneal macrophages. Taken together, our data indicate that MGG is a potent inducer of apoptosis on HL-60 cells and these abilities could be used clinically for the treatment of cancer.

Hyaluronan tetrasaccharide in the cerebrospinal fluid is associated with self-repair of rats after chronic spinal cord compression

The objective of this study was to explore changes in hyaluronan levels in the cerebrospinal fluid (CSF) in a spinal cord compression model, to investigate whether hyaluronan tetrasaccharide was involved in this process, and to test the effects of hyaluronan tetrasaccharide on neuron and oligodendrocyte repair. We developed a chronic spinal cord compression model with various sizes of polymer sheets (1.5×0.7×0.3 mm(3); 5×1.5×0.7 mm(3)) that were implanted microsurgically underneath the C(5-6) laminae. The rats were divided into three groups: a sham group, a mildly compressed (MC) group, and a widely compressed (WC) group. Locomotor functional evaluations revealed that the behavioral function of the MC and WC groups dropped to their lowest level from the fourth to fifth week and gradually recovered thereafter. The hyaluronan levels in the CSF gradually increased after spinal cord compression. Furthermore, hyaluronan tetrasaccharide was involved in the hyaluronan change. In addition, we found that nuclear factor kappa B (NF-κB) and cellular inhibitor-of-apoptosis protein 2 (c-IAP(2)) were co-expressed in neurons and oligodendrocytes, and caspase-3 expression gradually decreased in the compression model. The brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) expression was upregulated in astrocytes at the fourth week post-compression. Hyaluronan tetrasaccharide (HA(4)) induced NF-κB and c-IAP(2) to suppress the H(2)O(2)-induced apoptosis in primary neuronal cultures and increased BDNF and VEGF expression in astrocytic cultures in vitro. These findings suggest that HA(4) in the CSF may associate with behavioral recovery by increasing the levels of NF-κB, c-IAP(2), and neurotrophic factors after chronic spinal cord compression.

Associations of NF-kappaB and bax with apoptosis in varicose veins of women of different age groups

The study aimed at detecting apoptotic endothelial cells (ECs) and smooth muscle cells (SMCs) together with determining expression of NF-kappaB (p105/p50) and Bax in varicose vein walls. Women (n = 35) undergoing the excision of varicose veins were divided into 3 groups: younger than 35 years (I), 36–50 years (II), and older than 50 years (III). Apoptosis was determined by the TUNEL method, NF-kappaB and Bax expression by immunohistochemistry. The percentage of apoptotic ECs and SMCs in the layers of varicose vein wall increased in groups II and III. NF-kappaB expression had the lowest level in Group II with particularly low level in the media. Contrariwise, Bax expression levels in Group II were increased. The study revealed that in varicose veins ECs and SMCs apoptosis increased with advancing age. If increase in apoptosis during earlier stages of varicosities is probably regulated by intrinsic pathway, then in older patients other signaling pathways may be involved.

NF-κB signaling in the brain of autistic subjects

Autism is a neurodevelopmental disorder characterized by problems in communication, social skills, and repetitive behavior. Recent studies suggest that apoptotic and inflammatory mechanisms may contribute to the pathogenesis of this disorder. Nuclear factor-κB (NF-κB) is an important gene transcriptional factor involved in the mediation of inflammation and apoptosis. This study examined the activities of the NF-κB signaling pathway in the brain of autistic subjects and their age-matched controls. The NF-κB activation is also determined in the brain of BTBR mice, which is a promising animal model for study of pathogenic mechanisms responsible for autism. Our results showed that the level of IKKα kinase, which phosphorylates the inhibitory subunit IκBα, is significantly increased in the cerebellum of autistic subjects. However, the expression and phosphorylation of IκBα are not altered. In addition, our results demonstrated that the expression of NF-κB (p65), and the phosphorylation/activation of NF-κB (p65) at Ser536 are not significantly changed in the cerebellum and cortex of both autistic subjects and BTBR mice. Our findings suggest that the NF-κB signaling pathway is not disregulated in the brain of autistic subjects and thus may not be significantly involved in the processes of abnormal inflammatory responses suggested in autistic brain.

Mcl-1 and YY1 inhibition and induction of DR5 by the BH3-mimetic Obatoclax (GX15-070) contribute in the sensitization of B-NHL cells to TRAIL apoptosis

The pan Bcl-2 family antagonist Obatoclax (GX15-070), currently in clinical trials, was shown to sensitize TRAIL-resistant tumors to TRAIL-mediated apoptosis via the release of Bak and Bim from Mcl-1 or Bcl-2/Bcl-XL complexes or by the activation of Bax, though other mechanisms were not examined. Herein, we hypothesize that Obatoclax-mediated sensitization to TRAIL apoptosis may also result from alterations of the apoptotic pathways. The TRAIL-resistant B-cell line Ramos was used as a model for investigation. Treatment of Ramos cells with Obatoclax significantly inhibited the expression of several members of the Bcl-2 family, dissociated Bak from Mcl-1 and inhibited the NFκB activity. Cells treated with Mcl-1 siRNA were sensitized to TRAIL apoptosis. We examined whether the sensitization of Ramos to TRAIL by Obatoclax resulted from signaling of the DR4 and/or DR5. Transfection with DR5 siRNA, but not with DR4 siRNA, sensitized the cells to apoptosis following treatment with Obatoclax and TRAIL. The signaling via DR5 correlated with Obatoclax-induced inhibition of the DR5 repressor Yin Yang 1 (YY1). Transfection with YY1 siRNA sensitized the cells to TRAIL apoptosis following treatment with Obatoclax and TRAIL. Overall, the present findings reveal a new mechanism of Obatoclax-induced sensitization to TRAIL apoptosis and the involvement of the inhibition of NFκB activity and downstream Mcl-1 and YY1 expressions and activities.

Mitochondrial superoxide dismutase--signals of distinction

Mitochondrial superoxide dismutase (MnSOD) neutralizes the highly reactive superoxide radical (O(2)(˙-)), the first member in a plethora of mitochondrial reactive oxygen species (ROS). Over the past decades, research has extended the prevailing view of mitochondrion well beyond the generation of cellular energy to include its importance in cell survival and cell death. In the normal state of a cell, endogenous antioxidant enzyme systems maintain the level of reactive oxygen species generated by the mitochondrial respiratory chain. Mammalian mitochondria are important to the production of reactive oxygen species, which underlie oxidative damage in many pathological conditions and contribute to retrograde redox signaling from the organelle to the cytosol and nucleus. Mitochondria are further implicated in various metabolic and aging-related diseases that are now postulated to be caused by misregulation of physiological systems rather than pure accumulation of oxidative damage. Thus, the signaling mechanisms within mitochondria, and between the organelle and its environment, have gained interest as potential drug targets. Here, we discuss redox events in mitochondria that lead to retrograde signaling, the role of redox events in disease, and their potential to serve as therapeutic targets.

Helenalin bypasses Bcl-2-mediated cell death resistance by inhibiting NF-κB and promoting reactive oxygen species generation

Evasion of cell death by overexpression of anti-apoptotic proteins, such as Bcl-2, is commonly observed in cancer cells leading to a lack of response to chemotherapy. Hence, there is a need to find new chemotherapeutic agents that are able to overcome chemoresistance mediated by Bcl-2 and to understand their mechanisms of action. Helenalin, a sesquiterpene lactone (STL), induces cell death and abrogates clonal survival in a highly apoptosis-resistant Bcl-2 overexpressing Jurkat cell line as well as in two other Bcl-2 overexpressing solid tumor cell lines (mammary MCF-7; pancreatic L6.3pl). This effect is not achieved by directly affecting the mitochondria-protective function of Bcl-2 in the intrinsic pathway of apoptosis since Bcl-2 overexpressing Jurkat cells do not show cytochrome c release and dissipation of mitochondrial membrane potential upon helenalin treatment. Moreover, helenalin induces an atypical form of cell death with necrotic features in Bcl-2 overexpressing cells, neither activating classical mediators of apoptosis (caspases, AIF, Omi/HtrA2, Apaf/apoptosome) nor ER-stress mediators (BiP/GRP78 and CHOP/GADD153), nor autophagy pathways (LC3 conversion). In contrast, helenalin was found to inhibit NF-κB activation that was considerably increased in Bcl-2 overexpressing Jurkat cells and promotes cell survival. Moreover, we identified reactive oxygen species (ROS) and free intracellular iron as mediators of helenalin-induced cell death whereas activation of JNK and abrogation of Akt activity did not contribute to helenalin-elicited cell death. Our results highlight the NF-κB inhibitor helenalin as a promising chemotherapeutic agent to overcome Bcl-2-induced cell death resistance.

Phenolic fraction of tobacco smoke inhibits BPDE-induced apoptosis response and potentiates cell transformation: role of attenuation of p53 response

Polynuclear aromatic hydrocarbons (PAHs) present in tobacco smoke are regarded as chemical carcinogens. Previously, we observed that a weakly acidic phenolic fraction of tobacco smoke condensate (TSCPhFr), which is devoid of PAHs, significantly potentiates (±)-anti-BP-7,8-diol-9,10-epoxide (BPDE)-induced anchorage-independent cell growth of promotion-sensitive JB6 cell, indicating its tumor-promoting potential. In the present article, we report that further fractionation of phenolic components from TSCPhFr did not show any significant potentiation of BPDE-induced cell transformation by any of the HPLC-purified phenolic fractions, indicating several phenolic components as a whole are needed for observed activity. Although the tumor-promoting activity of weakly acidic phenolic fraction of tobacco smoke had been indicated long before, no studies have been pursued to understand the mechanism(s) underlying the tumor-promoting activity of TSCPhFr. We observed that BPDE, an ultimate carcinogenic metabolite of tobacco smoke carcinogen benzo[a]pyrene, elicits apoptosis induction, which is significantly inhibited by TSCPhFr. Increased cell transformation and decreased apoptosis by TSCPhFr were associated with attenuation of BPDE-induced p53 accumulation. JB6 cells transfected with p53 siRNA showed significantly less apoptosis induction by BPDE as compared to control cells. In p53 impaired cells (which are observed to have a faster growth rate as compared to normal cells), TSCPhFr has a practically negligible effect on apoptosis induction in response to BPDE. Also, in p53 null HCT116 p53(-/-) cells, BPDE-induced apoptosis is unresponsive to TSCPhFr. Inhibition of BPDE-induced NF-κB activation was also observed by us previously. Interestingly, treatment of cells with NF-κB-specific inhibitor IKK-NBD peptide showed no effect on BPDE-induced apoptosis, whereas TSCPhFr showed moderate inhibition of apoptosis in NF-κB inhibited cells as compared to control cells. Our observations indicate that attenuation of BPDE-induced p53 response has a role in apoptosis inhibition and increased cell transformation by TSCPhFr. These findings have implication with regard to the underlying mechanism of tumor-promoting activity of TSCPhFr in PAH-induced carcinogenesis. Although p53-mediated NF-κB activation has a role in apoptosis induction, the role of NF-κB in TSCPhFr-mediated potentiation of PAH-induced cell transformation is not clear from our studies.

Enforced expression of the apoptosis inhibitor Bcl-2 ablates tolerance induction in DNA-reactive B cells through a novel mechanism

How self tolerance is maintained during B cell development in the bone marrow has been a focal area of study in immunology. Receptor editing, anergy and clonal deletion all play important roles in the regulation of autoimmunity in the immature population. The mechanisms of tolerance induction in the periphery, however, are less well characterized. Overexpression of the apoptosis inhibitor Bcl-2 rescues autoreactive B cells from deletion and can contribute to the development of autoimmune disease in certain genetic backgrounds. Using a peptide-induced autoimmunity model, we recently identified a peripheral tolerance checkpoint in antigen-activated B cells that have undergone class switching and somatic hypermutation. At this checkpoint, receptor editing, induced by antigen engagement, dampened the autoantibody response. In this study, we show that receptor editing fails to be induced in antigen-activated DNA-reactive B cells that overexpress Bcl-2 (Bcl-2 Tg). The failure to induce RAG and receptor editing is likely due, at least partially, to the lack of self antigen. First, the levels of circulating DNA and of apoptotic bodies in the spleen of Bcl-2 Tg mice are significantly lower than in control mice. Second, in Bcl-2 Tg mice, RAG can be induced in a population of antigen-activated B cells by providing exogenous soluble antigen. These data suggest that, in addition to its anti-apoptotic activity, Bcl-2 may indirectly inhibit tolerance induction in B cells acquiring anti-nuclear antigen reactivity after peripheral activation by limiting the availability of self antigen.