Indomethacin can induce cell death in rat gastric parietal cells through alteration of some apoptosis- and autophagy-associated molecules

In clinical medicine, indomethacin (IND, a non-steroidal anti-inflammatory drug) is used variously in the treatment of severe osteoarthritis, rheumatoid arthritis, gouty arthritis or ankylosing spondylitis. A common complication found alongside the therapeutic characteristics is gastric mucosal damage. This complication is mediated through apoptosis and autophagy of the gastrointestinal mucosal epithelium. Apoptosis and autophagy are critical homeostatic pathways catalysed by caspases downstream of the gastrointestinal mucosal epithelial injury. Both act through molecular signalling pathways characterized by the initiation, mediation, execution and regulation of the cell regulatory cycle. In this study we hypothesized that dysregulated apoptosis and autophagy are associated with IND-induced gastric damage. We examined the spectra of in vivo experimental gastric ulcers in male Sprague-Dawley rats through gastric gavage of IND. Following an 18-hour fast, IND was administered to experimental rats. They were sacrificed at 3-, 6- and 12-hour intervals. Parietal cells (H⁺ , K⁺ -ATPase β-subunit assay) and apoptosis (TUNEL assay) were determined. The expression of apoptosis-signalling caspase (caspases 3, 8, 9 and 12), DNA damage (anti-phospho-histone H2A.X) and autophagy (MAP-LC3, LAMP-1 and cathepsin B)-related molecules in gastric mucosal cells was examined. The administration of IND was associated with gastric mucosal erosions and ulcerations mainly involving the gastric parietal cells (PCs) of the isthmic and upper neck regions and a time-dependent gradual increase in the number of apoptotic PCs with the induction of both apoptotic (upregulation of caspases 3 and 8) cell death and autophagic (MAP-LC3-II, LAMP-1 and cathepsin B) cell death. Autophagy induced by fasting and IND 3 hours initially prompted the degradation of caspase 8. After 6 and 12 hours, damping down of autophagic activity occurred, resulting in the upregulation of active caspase 8 and its nuclear translocation. In conclusion we report that IND can induce time-dependent apoptotic and autophagic cell death of PCs. Our study provides the first indication of the interactions between these two homeostatic pathways in this context.

Interleukin-24 is a novel diagnostic biomarker for the severity of acute kidney injury

There is a clinical need for sensitive acute kidney injury (AKI) biomarkers that enable early therapeutic interventions and prediction of disease prognosis. In this study, we monitored interleukin (IL)-24 expressed in kidneys with severe AKI that progresses to atrophic kidney in a mouse model of ischemia-reperfusion injury (IRI). Therefore, we evaluated IL-24 as a potential biomarker not only for early diagnosis of AKI, but also for predicting progression to chronic kidney disease (CKD). Serum IL-24 was detected earlier than the elevation of serum creatinine levels and urinary IL-24 was detected as early as neutrophil gelatinase associated lipocalin (NGAL) in severe AKI (60 min of IRI). In addition, serum and urine IL-24 levels tended to increase in relation to ischemia duration. In such kidneys, vascular smooth muscle cells expressed IL-24 in response to the injury in the renal tubular epithelial cell and its target was the renal tubular epithelial cell itself. IL-24 may play a pivotal role in the communication between tubular epithelial cells and vascular smooth muscle cells and, in conclusion, IL-24 can be used as a sensitive biomarker for AKI.

Ethanol-Induced Mitochondrial Damage in Sertoli Cells is Associated with Parkin Overexpression and Activation of Mitophagy

This study was conducted to elucidate the involvement of the PINK1-Parkin pathway in ethanol-induced mitophagy among Sertoli cells (SCs). In the research, adult rats were given intraperitoneal injections of ethanol (5 gm/kg) and sacrificed at various time periods within 24 h. Transmission electron microscopy was applied to reveal enhanced mitochondrial damage in SCs of the ethanol-treated rats (ETRs) in association with a significant increase in numbers of mitophagic vacuoles (mitophagosomes and autolysosomes) in contrast to very low levels in a control group treated with phosphate-buffered saline (PBS). This enhancement was ultra-structurally verified via observation of trapped mitochondria within LC3-labeled membranes, upregulation of LC3 protein levels, colocalization of LC3 and cytochrome c, and reduced expression of mitochondrial proteins. Importantly, Parkin expression was found to be upregulated in ETR SCs, specifically in mitochondria and mitophagosomes in addition to colocalization with PINK1 and pan-cathepsin, indicating augmented mitophagy. Transcription factor EB (TFEB, a transcription factor for autophagy and mitophagy proteins) was also found to be upregulated in nuclei of ETR SCs and associated with enhanced expression of iNOS. Enhanced Parkin-related mitophagy in ETR SCs may be a protective mechanism with therapeutic implications. To the authors’ knowledge, this is the first report demonstrating the ultrastructural characteristics and molecular mechanisms of Parkin-related mitophagy in ETR SCs.

Ethanol-Induced Autophagy in Sertoli Cells Is Specifically Marked at Androgen-Dependent Stages of the Spermatogenic Cycle: Potential Mechanisms and Implications

In a recent study, we reported that acute ethanol exposure enhanced autophagy in Sertoli cells (SCs) of adult rats. However, further research is needed to clarify the specific spermatogenic stage exhibiting the highest autophagic response, the mechanisms behind such specificity, and the related relevance to sperm. This brief report provides results indicating that stages VII–VIII (androgen-dependent or spermiation stages) of the spermatogenic cycle exhibited more marked autophagic response in acute-ethanol treated rats (ETRs) than other stages based on suppression of androgen receptor (AR), analysis of microtubule-associated protein 1 light chain 3 (LC3) (an autophagosomal marker) immunostaining in SCs, double labeling of LC3 and lysosomal proteins and electron microscopy. Ultrastructural observations and TUNEL method revealed a notable presence of phagocytosed apoptotic germ cells and retained sperm in SCs of ETRs at these specific stages—a finding rarely observed in control testes. In addition, PTEN-induced putative kinase 1 ( PINK1) (a sensor of mitochondrial damage and mitophagy) and giant lipid droplets were found to have accumulated in SCs of ETRs at same stages. Our data show novel findings indicating that stages VII–VIII of the spermatogenic cycle exhibit high levels of autophagy, specifically under stress conditions, as expressed by the term autophagic stages. This stage-specific upregulation of autophagy in SCs may be related to AR suppression, mitochondrial damage, lipid accumulation, and phagocytosis of apoptotic cells. The phenomenon may be an essential part of ensuring the viability of SCs and supporting germ cells in toxic environments.

Using Artificial DNA Sequence to Suppress Non-specific Bindings in Crude Nuclear Extract During Surface Plasmon Resonance Assay

OBJECTIVE

Surface plasmon resonance (SPR) has been extensively used to characterize the interactions between molecules in terms of their binding specificity, affinity, and kinetics. Practical procedures, however, for measurement of the protein-DNA association in crude nuclear extract are yet to be defined.

METHODS

Crude nuclear extract was obtained from MCF-7 cells or recombinant estrogen receptor alpha (ERα) was used for analysis. To suppress signal from non-specific bindings in SPR assay using Biacore, DNA fragments with minimal protein binding activity were identified in a database for transcription factors and included in the study.

RESULTS

It is known that when analytes were purified transcription factors, the dissociation curves in Biacore sensorgrams exhibit exponential tendency. Based on statistical analysis, the dissociation phase between the ERα complex from crude nuclear extract and DNA oligonucleotides could be fitted exponentially. Following extrapolation of the dissociation phase, theoretical amount of bound antibodies could be estimated and compared for significant difference.

CONCLUSION

Our procedures made SPR technique such as Biacore a practical technique for measurement of protein-DNA associations in crude nuclear extract with reproducible and reliable results.

Upregulation of autophagy and glycolysis markers in keloid hypoxic-zone fibroblasts: Morphological characteristics and implications

Keloid is a fibro-proliferative skin disorder with tumor-like behavior and dependence on anaerobic glycolysis (the Warburg effect), but its exact pathogenesis is unknown. Although autophagy is widely accepted as a lysosomal pathway for cell survival and cellular homeostasis (specifically upon exposure to stressors such as hypoxia), very few studies have investigated the involvement of autophagy and related glycolytic effectors in keloidogenesis. Here the authors examined the expression and cellular localization of autophagy proteins (LC3, pan-cathepsin), glycolytic markers (LDH, MCT1, MCT4) and the transcription factor HIF isoforms in human keloid samples using immunohistochemical analysis and double-labeling immunofluorescence methods. Based on H&E staining and expression of CD31, keloids were compartmentalized into hypoxic central and normoxic marginal zones. Vimentin-expressing fibroblasts in the central zone exhibited greater autophagy than their marginal-zone counterparts, as evidenced by increased LC3 puncta formation and co-localization with lysosomal pan-cathepsin. LDH (a lactate stimulator), MCT4 (a lactate exporter) and HIF-1 α expression levels were also higher in central-zone fibroblasts. Conversely, HIF-2 α expression was upregulated in fibroblasts and endothelial cells of the peripheral zone, while MCT1 was expressed in both zones. Taken together, these observations suggest that upregulation of autophagy and glycolysis markers in keloid hypoxic-zone fibroblasts may indicate a prosurvival mechanism allowing the extrusion of lactate to marginal-zone fibroblasts via metabolic coupling. The authors believe this is the first report on differential expression of autophagic and glycolytic markers in keloid-zone fibroblasts. The study results indicate that autophagy inhibitors and MCT4 blockers may have therapeutic implications in keloid treatment.

GABAB receptor regulates proliferation in the high-grade chondrosarcoma cell line OUMS-27 via apoptotic pathways

BACKGROUND

High-grade chondrosarcoma, which has a high incidence of local recurrence and pulmonary metastasis despite surgical resection, is associated with poor prognosis. Therefore, new and effective adjuvant therapies are urgently required for this disease. Gamma-aminobutyric acid (GABA), which acts as a neurotrophic factor during nervous system development, is related to the proliferation and migration of certain cancer cells. The GABAergic system, which is composed of GABA, the GABA-synthesizing enzyme glutamic acid decarboxylase (GAD), and GABA receptors, has an important function in nerve growth and development of neural crest. Therefore, the GABAergic system may play important functional roles in the proliferation of chondrosarcoma cells, which are derived from neural crest cells. We examined the anti-tumor effects of the GABAergic system on a chondrosarcoma cell line.

METHODS

We evaluated the underlying mechanisms of the anti-tumor effects of the GABAergic system, such as the involvement of different signaling pathways, apoptosis, and cell cycle arrest, in the high-grade chondrosarcoma cell line OUMS-27. In addition, we performed whole-cell patch-clamp recordings for Ca²⁺ currents and evaluated the changes in intracellular Ca²⁺ concentration via Ca²⁺ channels, which are related to the GABA_B receptor in high-grade chondrosarcoma cells.

RESULTS

The GABA_B receptor antagonist CGP had anti-tumor effects on high-grade chondrosarcoma cells in a dose-dependent manner. The activities of caspase 3 and caspase 9 were significantly elevated in CGP-treated cells compared to in untreated cells. The activity of caspase 8 did not differ significantly between untreated cells and CGP-treated cells. However, caspase 8 tended to be up-regulated in CGP-treated cells. The GABA_B receptor antagonist exhibited anti-tumor effects at the G1/S cell cycle checkpoint and induced apoptosis via dual inhibition of the PI3/Akt/mTOR and MAPK signaling pathways. Furthermore, the changes in intracellular Ca²⁺ via GABA_B receptor-related Ca²⁺ channels inhibited the proliferation of high-grade chondrosarcoma cells by inducing and modulating apoptotic pathways.

CONCLUSIONS

The GABA_B receptor antagonist may improve the prognosis of high-grade chondrosarcoma by exerting anti-tumor effects via different signaling pathways, apoptosis, cell cycle arrest, and Ca²⁺ channels in high-grade chondrosarcoma cells.

Expression of delta-like 3 is downregulated by aberrant DNA methylation and histone modification in hepatocellular carcinoma

Delta-like 3 (DLL3) is a member of the Delta/Serrate/Lag-2 family of ligands for the Notch receptor and plays a role in Notch signaling. We have previously revealed that the expression of DLL3 is silenced by aberrant DNA methylation and that overexpression of DLL3 in the HuH2 hepatocellular carcinoma (HCC) cell line induced apoptosis. In the present study, we first confirmed the methylation of DLL3 in HuH2 cells and analyzed the methylation status of the DLL3 promoter region by bisulfite sequencing. Furthermore, we investigated whether other epigenetic modifications, such as histone acetylation and histone methylation, affected the expression of DLL3. Treatment with the DNA methylation inhibitor, 5-azadeoxycytidine (5-Aza-dC) slightly reactivated DLL3 mRNA expression and bisulfite sequencing revealed that CpG sites in the DLL3 promoter region of the HuH2 cells were densely-methylated. In addition, a significant increase in the expression of DLL3 was observed when the cells were treated with 5-Aza-dC in combination with the histone deacetylase inhibitor trichostatin A. However, an inhibitor of the dimethylation of histone H3 lysine 9 (H3K9me2) or the trimethylation of histone H3 lysine 27 (H3K27me3), modifications that are associated with gene silencing, had no effect on DLL3 reactivation. In combination with the findings from our previous study, these results indicated that DLL3 expression was silenced in HCC cells by DNA methylation and was more readily affected by histone acetylation than histone methylation (H3K9me2 or H3K27me3).

PTBP1-associated microRNA-1 and -133b suppress the Warburg effect in colorectal tumors

It is known that pyruvate kinase in muscle (PKM), which is a rate-limiting glycolytic enzyme, has essential roles in the Warburg effect and that expression of cancer-dominant PKM2 is increased by polypyrimidine tract-binding protein 1 (PTBP1), which is a splicer of the PKM gene. In other words, PKM2 acts as a promoter of the Warburg effect. Previously, we demonstrated that the Warburg effect was partially established by down-regulation of several microRNAs (miRs) that bind to PTBP1 and that ectopic expression of these miRs suppressed the Warburg effect. In this study, we investigated the functions of miR-1 and -133b, which are well known as muscle-specific miRs, from the viewpoint of the Warburg effect in colorectal tumors. The expression levels of miR-1 and -133b were relatively high in colon tissue except muscle and very frequently down-regulated in 75 clinical colorectal tumors samples, even in adenomas, compared with those of the adjacent normal tissue samples. The ectopic expression of these miRs induced growth suppression and autophagic cell death through the switching of PKM isoform expression from PKM2 to PKM1 by silencing PTBP1 expression both in vitro and in vivo. Also, we showed that the resultant increase in the intracellular level of reactive oxygen species (ROS) was involved in this mechanism. Furthermore, PTBP1 was highly expressed in most of the 30 clinical colorectal tumor samples examined, even in adenomas. Our results suggested that PTBP1 and PTBP1-associated miR-1 and -133b are crucial molecules for the maintenance of the Warburg effect in colorectal tumors.

Ethanol enhances thymocyte apoptosis and autophagy in macrophages of rat thymi

Tingible body macrophages (TBMs) play essential roles in the phagocytosis of apoptotic lymphocytes, specifically under exposure to various stressors. Although excessive ethanol consumption may enhance thymocyte apoptosis, reports investigating the autophagic response of the thymus to ethanol toxicity are still lacking. We investigated apoptosis and autophagy in thymi of an animal model of binge ethanol exposure. Adult male Wistar rats were injected intraperitoneally either with 5 g/kg ethanol or phosphate buffer saline (for the control group) and sacrificed 0, 3, 6 and 24 hours after injection. Light and transmission electron microscopy (TEM) studies revealed enhanced formation of TBMs phagocytosing many apoptotic thymocytes in the thymic cortex of the ethanol-treated rats (ETRs), and this formation was particularly marked at 24 h. The macrophages showed signs of activation under TEM and immunofluorescence double labeling with RM4 (a macrophage marker) and iNOS. Additionally, in comparison to the control group, autophagy was enhanced in ETR thymic TBMs as evidenced ultrastructurally by accumulation of autophagic vacuoles, immunohistochemical increases in LC3 puncta, Western blot analysis of the latter protein, and colocalization of LC3 and RM4 in immunofluorescence double labeling. Immunoelectron microscopy also revealed LC3-labeled autophagic vacuoles and apoptotic cell phagosomes in ETR TBMs, suggesting the possibility of LC3-related phagocytosis. This was confirmed by enhanced colocalization of LC3 with lysosomal cathepsins in double labeling. These results indicate that enhanced autophagy in ETR thymic TBMs is not only a cytoprotective mechanism but could also be involved in the clearance of apoptotic thymocytes, thus preventing autoimmune reactions and suppressing inflammatory response.

Homeobox family Hoxc localization during murine palate formation

Homeobox genes play important roles in craniofacial morphogenesis. However, the characteristics of the transcription factor Hoxc during palate formation remain unclear. We examined the immunolocalization patterns of Hoxc5, Hoxc4, and Hoxc6 in palatogenesis of cleft palate (Eh/Eh) mice. On the other hand, mutations in the FGF/FGFR pathway are exclusively associated with syndromic forms of cleft palate. We also examined the immunolocalization of Fgfr1 and Erk1/2 to clarify their relationships with Hoxc in palatogenesis. Some palatal epithelial cells showed Hoxc5 labeling, while almost no labeling of mesenchymal cells was observed in +/+ mice. As palate formation progressed in +/+ mice, Hoxc5, Hoxc4, and Hoxc6 were observed in medial epithelial seam cells. Hoxc5 and Hoxc6 were detected in the oral epithelium. The palatal mesenchyme also showed intense staining for Fgfr1 and Erk1/2 with progression of palate formation. In contrast, the palatal shelves of Eh/Eh mice exhibited impaired horizontal growth and failed to fuse, resulting in a cleft. Hoxc5 was observed in a few epithelial cells and diffusely in the mesenchyme of Eh/Eh palatal shelves. No or little labeling of Fgfr1 and Erk1/2 was detected in the cleft palate of Eh/Eh mice. These findings suggest that Hoxc genes are involved in palatogenesis. Furthermore, there may be the differences in the localization pattern between Hoxc5, Hoxc4, and Hoxc6. Additionally, Hoxc distribution in palatal cells during palate development may be correlated with FGF signaling. (228/250 words) © 2016 Japanese Teratology Society.

Identification of c-Jun as bcl-2 Transcription Factor in Human Uterine Endometrium

We describe the application of the biomolecular interaction (BIA) technique to detection of the interaction between protein (e.g., c-Jun) and DNA (e.g., two AP-1 motifs from bcl-2 promoter), compared with immunohistochemistry (IHC) of c-Jun. The specific binding assay for the interaction of c-Jun and activating protein-1 (AP-1) motifs was performed using a Biacore 2000 system. Intense immunoreactivity of c-Jun in glandular cells of the human uterine endometrium was observed in the proliferative phase, while c-Jun in stromal cells was expressed throughout the menstrual cycle. In contrast to the IHC of c-Jun, the specific binding of c-Jun to two separate AP-1 motifs in the bcl-2 promoter region was detected only in nuclear extracts of glandular cells, but not in stromal cells, during the proliferative phase. These results indicate that, while transmitting various signals, c-Jun enhances the transcription level of bcl-2, which in turn keeps glandular cells alive and proliferating in normal human endometrium during the proliferative phase. Moreover, the method involving real-time biomolecular interactions such as DNA-protein binding is novel for the study of transcription factors when combined with IHC.

Triggering of Parkin Mitochondrial Translocation in Mitophagy: Implications for Liver Diseases

A growing body of evidence based on in vitro studies indicates that mitophagy (selective autophagic clearance of damaged mitochondria) is a prosurvival mechanism associated with cellular exposure to various mitochondrial stressors. Very recently, a limited number of publications on animal-based models of alcoholic fatty liver diseases have reported that Parkin-mediated mitophagy may mitigate hepatocyte apoptosis, improve mitochondrial quality and suppress steatosis (lipid accumulation). From this perspective, the authors focus on the mechanisms of Parkin mitochondrial translocation (a key consideration in mitophagy activation) and therapeutic implications of mitophagy in liver disease. DNA repair and other functions of Parkin beyond mitophagy are also briefly discussed. The paper additionally shows original data from the authors' current research indicating enhanced hepatic mitophagy in ethanol-treated rats, which is associated with Parkin mitochondrial translocation triggered by oxidative mitochondrial DNA damage. Natural or pharmaceutical products that may trigger Parkin mitochondrial translocation in hepatocytes and/or suppress repressors of such translocation could be a potential therapeutic target in alcoholic and non-alcoholic fatty liver disease.

Ethanol-induced mitophagy in liver is associated with activation of the PINK1-Parkin pathway triggered by oxidative DNA damage

Mitophagy is a cytoprotective mechanism against mitochondrial damaging agents. Studies demonstrating morphological evidence for the involvement of the PINK1-Parkin pathway in the hepatocyte mitophagic response to ethanol toxicity, and potential links to apoptosis and mitochondrial alterations such as spheroid formation are still lacking. We addressed these unresolved issues using a rat model of binge alcohol exposure. Adult rats were injected with ethanol (5g/kg) and liver samples were taken at 0, 3, 6, and 24 hours after ethanol administration and processed for light and electron microscopic studies. Ethanol induced a low level of hepatocyte apoptosis, peaking at 3 h and decreasing significantly by 24 h. In contrast, there was enhanced formation of mitophagic vacuoles in the majority of normal hepatocytes of ethanol-treated rats (ETRs), which peaked at 6 h and was maintained up to 24 h based on electron microscopy and TUNEL/LC3 double labelling. Moreover, enhanced mitophagy in ETR hepatocytes was confirmed by increased LC3 puncta formation, and co-localization of Parkin and LC3 with mitochondrial and lysosomal markers. Immunoelectron microscopy demonstrated the localization of PINK1 and Parkin to damaged mitochondria of ETR hepatocytes, which was consistent with co-localization of Parkin with 8-OHdG, a marker of oxidative mitochondrial DNA damage. Furthermore, electron microscopy showed enhanced formation of mitochondrial spheroids in ETR hepatocytes. These data are the first direct morphological evidence linking PINK1-Parkin pathway activation to the enhanced mitophagic response of hepatocytes to ethanol toxicity. Ethanol-induced hepatic mitophagy may be a prosurvival mechanism, which may have therapeutic implications.

MicroRNA-124 inhibits cancer cell growth through PTB1/PKM1/PKM2 feedback cascade in colorectal cancer

Altered levels and functions of microRNAs (miRs) have been associated with carcinogenesis. In this study, we investigated the role of miR-124 in colorectal adenoma (CRA) and cancer (CRC). The expression levels of miR-124 were decreased in CRA (81.8%) and CRC (57.6%) in 55 clinical samples. The ectopic expression of miR-124 induced apoptosis and autophagy in colon cancer cells. Also, miR-124 targeted polypyrimidine tract-binding protein 1 (PTB1), which is a splicer of pyruvate kinase muscles 1 and 2 (PKM1 and PKM2) and induced the switching of PKM isoform expression from PKM2 to PKM1. Also, siR-PTB1 induced drastic apoptosis in colon cancer cells. Furthermore, we found that the ectopic expression of miR-124 enhanced oxidative stress and the miR-124/PTB1/PKM1/PKM2 axis constituted a feedback cascade. Finally, we showed that intratumor injection of miR-124 and siR-PTB1 induced a tumor-suppressive effect in xenografted mice. The axis was established by both in vitro and in vivo experiments to function in human colorectal cancer cells. These findings suggest that miR-124 acts as a tumor-suppressor and a modulator of energy metabolism through a PTB1/PKM1/PKM2 feedback cascade in human colorectal tumor cells.

Positive feedback of DDX6/c-Myc/PTB1 regulated by miR-124 contributes to maintenance of the Warburg effect in colon cancer cells

The human DEAD/H-box RNA helicase gene DDX6 is a target of the t(11;14)(q23;q32) chromosomal translocation observed in human B-cell lymphoma, and the overexpression of its protein has been shown to cause malignant transformation. DDX6 has a variety of functions such as translation initiation, pre-mRNA splicing, ribosome assembly, and more. However, details of the regulatory mechanism of DDX6 and functions of DDX6 in cancer cells are largely unknown. On the other hand, the Warburg effect is a well-known feature of cancer cells. Pyruvate kinase in muscle (PKM), which is a rate-limiting glycolytic enzyme, has 2 isoforms, PKM1 and PKM2. It has been frequently reported that PKM2 is a tumor-specific isoform and promotes the Warburg effect. However, the functions of the PKM1 gene have been hardly mentioned. Here, we showed that DDX6 was overexpressed in colorectal cancer specimens and regulated by microRNA (miR)-124 in colon cancer cells. Also, a DDX6/c-Myc/PTB1 positive feedback circuit regulated by miR-124 was shown to be established and to contribute to maintenance of the Warburg effect. Moreover, we showed that knockdown of DDX6 induced mainly apoptosis through an imbalance of PKM gene expression, especially causing down-regulation of PKM1 in colon cancer cells. These results suggest that miR-124 is a fine tuner of the Warburg effect and that DDX6 is one of the key molecules in Warburg effect-related miR-124 targeting various genes.

Ethanol-induced hepatic autophagy: Friend or foe?

Excessive alcohol intake may induce hepatic apoptosis, steatosis, fibrosis, cirrhosis and even cancer. Ethanol-induced activation of general or selective autophagy as mitophagy or lipophagy in hepatocytes is generally considered a prosurvival mechanism. On the other side of the coin, upregulation of autophagy in non-hepatocytes as stellate cells may stimulate fibrogenesis and subsequently induce detrimental effects on the liver. The autophagic response of other non-hepatocytes as macrophages and endothelial cells is unknown yet and needs to be investigated as these cells play important roles in ethanol-induced hepatic steatosis and damage. Selective pharmacological stimulation of autophagy in hepatocytes may be of therapeutic importance in alcoholic liver disease.

Anti-cancer fatty-acid derivative induces autophagic cell death through modulation of PKM isoform expression profile mediated by bcr-abl in chronic myeloid leukemia

The fusion gene bcr-abl develops chronic myeloid leukemia (CML), and stimulates PI3K/Akt/mTOR signaling, leading to impaired autophagy. PI3K/Akt/mTOR signaling also plays an important role in cell metabolism. The Warburg effect is a well-recognized hallmark of cancer energy metabolism, and is regulated by the mTOR/c-Myc/hnRNP/PKM signaling cascade. To develop a new strategy for the treatment of CML, we investigated the associations among bcr-abl, the cascade related to cancer energy metabolism, and autophagy induced by a fatty-acid derivative that we had previously reported as being an autophagy inducer. Here we report that a fatty-acid derivative, AIC-47, induced transcriptional repression of the bcr-abl gene and modulated the expression profile of PKM isoforms, resulting in autophagic cell death. We show that c-Myc functioned as a transcriptional activator of bcr-abl, and regulated the hnRNP/PKM cascade. AIC-47, acting through the PPARγ/β-catenin pathway, induced down-regulation of c-Myc, leading to the disruption of the bcr-abl/mTOR/hnRNP signaling pathway, and switching of the expression of PKM2 to PKM1. This switching caused autophagic cell death through an increase in the ROS level. Our findings suggest that AIC-47 induced autophagic cell death through the PPARγ/β-catenin/bcr-abl/mTOR/hnRNP/PKM cascade.

Organ-specific PTB1-associated microRNAs determine expression of pyruvate kinase isoforms

The Warburg effect is a well-known feature of cancer cells. However, its' functional significance hasn't been elucidated yet. Pyruvate kinase muscle (PKM), which is a rate-limiting glycolytic enzyme, has 2 isoforms, PKM1 and PKM2. It has been reported that PKM2 is a tumor-specific isoform and promotes the Warburg effect. Also, it has been thought that tumor cells switch their PKM isoform from PKM1 to PKM2 during tumor development. Here, we showed that this switching machinery was induced only in limited cases, based on PKM expression in normal tissues, and that brain-specific microRNA (miR)-124 and muscle-specific miR-133b regulated this machinery by controlling PKM expression through targeting polypyrimidine tract-binding protein 1 (PTB1), which is a splicer of the PKM gene. Also, we confirmed that the PKM2/PKM1 ratio was further elevated in other PKM2-dominant organs such as colon through the down-regulation of these PTB1-associated microRNAs during tumor development.

Chymase inhibition attenuates lipopolysaccharide/ d-galactosamine-induced acute liver failure in hamsters

BACKGROUND/AIMS

Chymase inhibition has been shown to attenuate matrix metalloproteinase (MMP)-9 and tumor necrosis factor (TNF)-α, both of which are associated with the pathogenesis of acute liver failure (ALF). This study investigated the effects of the chymase inhibitor TY-51469 on lipopolysaccharide (LPS)/D-galactosamine (GalN)-induced ALF in hamsters.

METHODS

TY-51469 (10 or 30 mg/kg) or placebo was administered 1 h before the LPS (160 µg/kg)/GalN (400 mg/kg) injection.

RESULTS

Hepatic chymase activity was significantly increased after the LPS/GalN injection, but the significant increase was dose-dependently and significantly attenuated by treatment with TY-51469. Significant increases in hepatic MMP-9 activity and TNF-α concentration were observed after the LPS/GalN injection, but these increases were also attenuated by treatment with TY-51469. Plasma aspartate aminotransferase and alanine aminotransferase activities were significantly increased after LPS/GalN injection in the placebo-treated group, but the increases were significantly attenuated in the TY-51469-treated group. The area of hepatic necrotic after LPS/GalN injection was significantly reduced by treatment with TY-51469. Treatment with TY-51469 resulted in significant reductions in the hepatic malondialdehyde concentration, mast cell numbers, and gene expressions of interleukin-1β and myeloperoxidase.

DISCUSSION

Chymase inhibition could be a useful strategy to attenuate LPS/GalN-induced ALF in hamsters.

Chymase inhibitor ameliorates hepatic steatosis and fibrosis on established non-alcoholic steatohepatitis in hamsters fed a methionine- and choline-deficient diet

AIM

Chymase plays a role in the augmentation of angiotensin II formation, which is involved in liver fibrosis. The therapeutic effects of a chymase inhibitor, TY-51469, on established hepatic steatosis and fibrosis were investigated in a model of developed non-alcoholic steatohepatitis.

METHODS

Hamsters were fed a normal diet or methionine- and choline-deficient (MCD) diet for 12 weeks. Then, treatment with TY-51469 (1 mg/kg per day) or placebo was initiated, and the treatment was continued concurrently with the MCD diet for an additional 12 weeks.

RESULTS

At 12 weeks after initiating the MCD diet, marked hepatic steatosis and fibrosis were observed in MCD diet-fed hamsters. Malondialdehyde and gene expression levels of collagen I, collagen III, α-smooth muscle actin (α-SMA) and Rac-1 in liver extracts were also increased in the MCD-diet-fed hamsters at 12 weeks. At 24 weeks, hepatic steatosis and fibrosis were more prominent in the placebo-treated hamsters that were fed the MCD-diet for 24 weeks versus 12 weeks. Hamsters treated with TY-51469 for 12 weeks after being on a 12-week MCD diet had significant ameliorations in both hepatic steatosis and fibrosis, and there were no significant differences compared to normal diet-fed hamsters. There were significant augmentations in angiotensin II and malondialdehyde, and gene expressions of collagen I, collagen III, α-SMA and Rac-1 in the placebo-treated hamsters at 24 weeks; however, these levels were reduced to normal levels in the TY-51469-treated hamsters.

CONCLUSION

TY-51469 not only prevented the progression of hepatic steatosis and fibrosis, but also ameliorated hepatic steatosis and fibrosis.

Regulation of bcl-2 transcription by estrogen receptor-α and c-Jun in human endometrium

The estrogen-estrogen receptor (ER) signaling pathway plays crucial physiologic roles in not only the control of reproduction, but also in the generation of cancer in the breast and uterus. While some ER target genes have been identified containing the estrogen-responsive element (ERE), others are activated eventually by ER via protein-protein interaction without binding to ERE. In a previous study, we identified that the proliferative phase-specific expression of the bcl-2 gene in glandular cells could be regulated by the binding of c-Jun to its motifs in the promoter. Results from our present study indicate that the menstrual cyclic expression of bcl-2 could be controlled by either direct binding of ERα to ERE in the c-Jun promoter or the interaction of ERα with c-Jun that binds to its motifs in the bcl-2 gene. Intriguingly, the transcriptionally active form of c-Jun phosphorylated at Ser63 was identified binding to its motifs in the bcl-2 gene in a menstrual cyclic non-specific manner. Our study revealed a novel mechanism that transcriptionally regulates the expression of bcl-2 in the normal human endometrium.

Thoracic duct relationships to abnormal neurovascular structures in cervicothoracic regions: case study and clinical relevance

The presence of variant intercostal and bronchial arteries and variable position of left recurrent laryngeal nerve (LRLN) along the course of thoracic duct (TD) may have clinical relevance in various cervicothoracic surgeries.

Chymase inhibition attenuates monocrotaline-induced sinusoidal obstruction syndrome in hamsters

Chymase stored in mast cells activates matrix metalloproteinase (MMP)-9, which may relate to the progression of sinusoidal obstruction syndrome (SOS). We investigated the preventive effect of a chymase inhibitor, TY-51469, on monocrotaline-induced SOS in hamsters. Hamsters were orally administrated with a single dose of monocrotaline (120 mg/kg) to induce SOS. Treatment with TY-51469 (1 mg/kg per day) or placebo had started 3 days before the monocrotaline administration. Two days after the monocrotaline administration, significant increases in aspartate aminotransferase, alanine aminotransferase and total bilirubin and a significant reduction of albumin were observed in plasma, but their changes were significantly attenuated by treatment with TY-51469. The numerous hepatic necrosis areas were observed in the placebo-treated group, but the ratio of necrotic area to total area in liver had been significantly reduced by treatment with TY-51469. Both chymase activity and MMP-9 level in liver were significantly augmented in the placebo-treated group. Furthermore, tumor necrosis factor (TNF)-α level in liver was also augmented in the placebo-treated group. However, the chymase activity and levels of MMP-9 and TNF-α were significantly attenuated in the TY-51469-treated group. Until 14 days after monocrotaline administration, survival rates in the placebo- and TY-51469-treated groups were 25% and 70%, respectively, and a significant difference was observed. In conclusion, chymase inhibition by TY-51469 may prevent the accelerating of severity in monocrotaline-induced SOS in hamsters.

Heparanase localization during palatogenesis in mice

Palatogenesis is directed by epithelial-mesenchymal interactions and results partly from remodeling of the extracellular matrix (ECM) of the palatal shelves. Here, we assessed heparanase distribution in developing mouse palates. No heparanase was observed in the vertically oriented palatal shelves in early stages of palate formation. As palate formation progressed, the palatal shelves were reorganized and arranged horizontally above the tongue, and heparanase localized to the epithelial cells of these shelves. When the palatal bilateral shelves first made contact, the heparanase localized to epithelial cells at the tips of shelves. Later in fusing palatal shelves, the cells of the medial epithelial seam (MES) were labeled with intense heparanase signal. In contrast, the basement membrane heparan sulfate (HS) was scarcely observed in the palatal shelves in contact. Moreover, perlecan labeling was sparse in the basement membrane of the MES, on which laminin and type IV collagen were observed. Moreover, we assessed the distribution of matrix metalloproteinase- (MMP-) 9, MMP-2, and MMP-3 in developing mouse palates and these MMPs were observed in the MES. Our findings indicated that heparanase was important for palate formation because it mediated degradation of the ECM of palatal shelves. Heparanase may, in concert with other proteases, participate in the regression of the MES.

Elevated autophagic sequestration of mitochondria and lipid droplets in steatotic hepatocytes of chronic ethanol-treated rats: an immunohistochemical and electron microscopic study

Ethanol-induced hepatic steatosis may induce the progression of alcoholic liver disease. The involvement of autophagic clearance of damaged mitochondria (mitophagy) and lipid droplets (LDs) (lipophagy) in chronic ethanol-induced hepatic steatosis is not clearly understood. Adult Wistar rats were fed either 5 % ethanol in Lieber-DeCarli liquid diet or an isocaloric control diet for 10 weeks. Light microscopy showed marked steatosis in hepatocytes of ethanol-treated rats (ETRs), which was further revealed by transmission electron microscopy (TEM), where significant numbers of large LDs and damaged mitochondria were detected in steatotic hepatocytes. Moreover, TEM demonstrated that hepatocyte steatosis was associated with greatly enhanced autophagic vacuole (AV) formation compared to control hepatocytes. Mitochondria and LDs were the predominant contents of AVs in steatotic hepatocytes. Immunohistochemistry of LC3, a specific marker of early AVs (autophagosomes), demonstrated an extensive punctate pattern in hepatocytes of ETRs, while LC3 puncta were much less frequent in control hepatocytes. This was confirmed by immunoelectron microscopy (IEM), which showed localization of LC3 to autophagosomes sequestering damaged mitochondria and LDs. In addition, IEM revealed that PINK1 (a sensor of mitochondrial damage and marker of mitophagy) was overexpressed in mitochondria of ETRs. Enhanced autophagic lysosomal activity was evidenced by increased immunolabeling of LAMP-2, a marker of late AVs (autolysosomes) in hepatocytes of ETRs and colocalization of LC3 and lysosomal cathepsins using double immunofluorescence labeling. Increased AVs in hepatocytes of ETRs reflect ethanol toxicity and could represent a possible protective mechanism via stimulation of mitophagy and lipophagy.

Delta-like 3 is silenced by methylation and induces apoptosis in human hepatocellular carcinoma

The genetic and epigenetic events of hepatocarcinogenesis are relatively poorly understood. By analyzing genes from human hepatocellular carcinoma (HCC) with restriction landmark genomic scanning, several aberrantly methylated genes, including Delta-like 3 (DLL3), have been isolated. In this study, we investigated the function of DLL3 in hepatocarcinogenesis. Methylation of the DLL3 gene in HCC cell lines was investigated with methylation-specific PCR and expression of DLL3 mRNA in HCC cells was examined by RT-PCR. Reactivation of DLL3 expression by treatment with a demethylating agent was examined in methylation-silenced HuH2 cells. Human DLL3 cDNA was cloned and DLL3 function was examined by restoring DLL3 expression in HuH2 cells. The effects of DLL3 on cell growth were evaluated by colony formation assay. Induction of cell death by overexpression of DLL3 was examined by flow cytometric assay using Annexin V and PI. Apoptotic cells were detected by TUNEL staining and the amount of single-stranded DNA was measured by ELISA. As a result, the promoter region of the DLL3 gene was methylated in four of ten HCC cell lines. This aberrant methylation correlated well with the suppression of RNA expression and a demethylating agent reactivated DLL3 expression in methylation-silenced HCC cells. Interestingly, the restoration of DLL3 in the methylation-silenced HuH2 cells led to growth suppression on colony formation assay. Flow cytometric assay with Annexin V and PI showed that this growth suppression by DLL3 expression is associated with the induction of apoptosis. Furthermore, these apoptotic effects were confirmed by TUNEL staining and measurement of single-stranded DNA. These results suggest that DLL3 was silenced by methylation in human HCC and that it negatively regulates the growth of HCC cells.

Enhanced mitophagy in Sertoli cells of ethanol-treated rats: morphological evidence and clinical relevance

Although chronic ethanol consumption results in Sertoli cell vacuolization and augmented testicular germ cell apoptosis via death receptor and mitochondrial pathways, Sertoli cells are resistant to apoptosis. The aim of this study was to examine whether the activation of autophagy in the Sertoli cells of ethanol-treated rats (ETR) may have a role in their survival. Adult Wistar rats were fed either 5% ethanol in Lieber-DeCarli liquid diet or an isocaloric control diet for 12 weeks. The TUNEL method demonstrated that Sertoli cells were always TUNEL-negative despite the presence of many apoptotic germ cells in ETR, supporting our previous studies. Electron microscopy revealed the presence of large numbers of autophagic vacuoles (AVs) in Sertoli cells of ETR compared to few AVs in control testes. Most of the AVs in Sertoli cells of ETR enveloped and sequestered damaged and abnormally shaped mitochondria, without cytoplasm, indicating mitochondrial autophagy (mitophagy). Immuno-electron microscopy showed the localization of LC3, a specific marker of early AVs (autophagosomes), around AVs sequestering mitochondria in Sertoli cells of ETR. Immunohistochemical staining of LC3 demonstrated a punctate pattern in Sertoli cells of ETR, confirming the formation of autophagosomes, while LC3 puncta were almost absent in control testes. Moreover, increased immunoreactivity of LAMP-2, a lysosomal membrane protein and marker of late AVs (autolysosomes), was mainly observed in Sertoli cells of ETR, with weaker expression in control testes. Via the deletion of pro-apoptotic damaged mitochondria, enhanced Sertoli cell mitophagy in ETR may be an anti-apoptotic mechanism that is essential for spermatogenesis.

Lymphangiogenesis and Axillary Lymph Node Metastases Correlated with VEGF-C Expression in Two Immunocompetent Mouse Mammary Carcinoma Models

Lymphangiogenesis and the expression of vascular endothelial cell growth factor C (VEGF-C) in tumors have been considered to be causally promoting lymphatic metastasis. There are only a few studies on lymphatic metastasis in immunocompetent allograft mouse models. To study the relationship between VEGF-C-mediated lymphangiogenesis and axillary lymph node metastasis, we used two mouse mammary carcinoma cell lines; the BJMC338 has a low metastatic propensity, whereas the BJMC3879 has a high metastatic propensity although it originated from the former cell line. Each cell line was injected separately into two groups of female BALB/c mice creating in vivo mammary cancer models. The expression level of VEGF-C in BJMC3879 was higher than BJMC338. As the parent cell line, BJMC3879-derived tumors showed higher expression of VEGF-C compared to BJMC338-derived tumors. This higher expression of VEGF-C in BJMC3879-derived tumors was associated with marked increase in infiltrating macrophages and enhanced expression of lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1) reflecting increased tumoral lymphatic density and subsequent induction of axillary lymph node metastasis. Our mouse mammary carcinoma models are allotransplanted tumors showing the same axillary lymph node metastatic spectrum as human breast cancers. Therefore, our mouse models are ideal for exploring the various molecular mechanisms of cancer metastasis.