Castleman's disease is a rare disorder characterized by benign tumors that may develop in the lymph node tissue throughout the body. Castleman's disease associated with myasthenia gravis is an especially rare disease. Only less than 10 cases have been reported in the world literature. The cause of Castleman's disease is associated with immune mediated reaction, and myasthenia gravis also develops due to an antibody-mediated process. The cause of myasthenia gravis is the immune activity of Castleman's disease, which may be the promoter of the antibody-mediated process. We report here a case of Castleman's disease, which was incidentally found in a patient diagnosed with myasthenia gravis.
Myasthenia gravis; Thymectomy; Retroperitoneal neoplasms
A 70-year-old male visited urgent care due to coughing for 1 month and left chest pain. He had no history of trauma. The initial chest computed tomography (CT) showed the 7th left intercostal lung herniation. A follow-up CT showed an intercostal lung herniation combined with a bowl herniation, which had developed due to a Morgagni's hernia. An emergency operation was performed due to the incarceration of the bowl and lung. The primary repair of the diaphragm was performed and the direct approximation of the 7th intercostal space was determined. We concluded that the defect of the diaphragm and the intercostal muscle was a congenital lesion, and the recurrent coughing was the aggravating factor of herniation.
Morgagni's hernia; Hernia, lung
ULK1 (Unc51-like kinase, hATG1) is a Ser/Thr kinase that plays a key role in inducing autophagy in response to starvation. ULK1 is phosphorylated and negatively regulated by the mammalian target of rapamycin complex 1 (mTORC1). Previous studies have shown that ULK1 is not only a downstream effector of mTORC1 but also a negative regulator of mTORC1 signaling.1–3 Here, we investigated how ULK1 regulates mTORC1 signaling, and found that ULK1 inhibits the kinase activity of mTORC1 and cell proliferation. Deficiency or knockdown of ULK1 or its homolog ULK2 enhanced mTORC1 signaling, cell proliferation rates and accumulation of cell mass, whereas overexpression of ULK1 had the opposite effect. Knockdown of Atg13, the binding partner of ULK1 and ULK2, mimicked the effects of ULK1 or ULK2 deficiency or knockdown. Both insulin and leucine stimulated mTORC1 signaling to a greater extent when ULK1 or ULK2 was deficient or knocked down. In contrast, Atg5 deficiency did not have a significant effect on mTORC1 signaling and cell proliferation. The stimulatory effect of ULK1 knockdown on mTORC1 signaling occurred even in the absence of tuberous sclerosis complex 2 (TSC2), the negative regulator of mTORC1 signaling. In addition, ULK1 was found to bind raptor, induce its phosphorylation, and inhibit the kinase activity of mTORC1. These results demonstrate that ULK1 negatively regulates the kinase activity of mTORC1 and cell proliferation in a manner independent of Atg5 and TSC2. The inhibition of mTORC1 by ULK1 may be important to coordinately regulate cell growth and autophagy with optimized utilization of cellular energy.
ULK1; ULK2; Atg5; raptor; mTOR
Nutrient starvation induces autophagy in eukaryotic cells through inhibition of TOR (target of rapamycin), an evolutionarily-conserved protein kinase. TOR, as a central regulator of cell growth, plays a key role at the interface of the pathways that coordinately regulate the balance between cell growth and autophagy in response to nutritional status, growth factor and stress signals. Although TOR has been known as a key regulator of autophagy for more than a decade, the underlying regulatory mechanisms have not been clearly understood. This review discusses the recent advances in understanding of the mechanism by which TOR regulates autophagy with focus on mammalian TOR (mTOR) and its regulation of the autophagy machinery.
mTOR; Atg1; ULK1; ULK2; Atg13
Vacuum-assisted closure therapy is an alternative method for a massive subcutaneous emphysema treatment. It is easily applicable and shows rapid effectiveness in massive subcutaneous emphysema, intractable with chest tube drainage.
Subcutaneous emphysema; Device; Negative pressure
Autophagy, the starvation-induced degradation of bulky cytosolic components, is up-regulated in mammalian cells when nutrient supplies are limited. Although mammalian target of rapamycin (mTOR) is known as the key regulator of autophagy induction, the mechanism by which mTOR regulates autophagy has remained elusive. Here, we identify that mTOR phosphorylates a mammalian homologue of Atg13 and the mammalian Atg1 homologues ULK1 and ULK2. The mammalian Atg13 binds both ULK1 and ULK2 and mediates the interaction of the ULK proteins with FIP200. The binding of Atg13 stabilizes and activates ULK and facilitates the phosphorylation of FIP200 by ULK, whereas knockdown of Atg13 inhibits autophagosome formation. Inhibition of mTOR by rapamycin or leucine deprivation, the conditions that induce autophagy, leads to dephosphorylation of ULK1, ULK2, and Atg13 and activates ULK to phosphorylate FIP200. These findings demonstrate that the ULK-Atg13-FIP200 complexes are direct targets of mTOR and important regulators of autophagy in response to mTOR signaling.
Nanoparticles based on stimuli-sensitive drug delivery have been extensively investigated for tumor targeting. Among them, pH-responsive drug targeting using pH-sensitive polymers has attracted attention because solid tumors have an acidic environment. A dextran-b-poly(L-histidine) (DexPHS) copolymer was synthesized and pH-responsive nanoparticles were fabricated for drug targeting.
Methods and results
A DexPHS block copolymer was synthesized by attaching the reductive end of dextran to the amine groups of poly(L-histidine). pH-responsive nanoparticles incorporating doxorubicin were fabricated and studied in HuCC-T1 cholangiocarcinoma cells. Synthesis of DexPHS was confirmed by 1H nuclear magnetic resonance spectroscopy, with specific peaks of dextran and PHS observed at 2–5 ppm and 7.4–9.0 ppm, respectively. DexPHS nanoparticles showed changes in particle size with pH sensitivity, ie, the size of the nanoparticles increased at an acidic pH and decreased at a basic pH. DexPHS block copolymer nanoparticles incorporating doxorubicin were prepared using the nanoprecipitation dialysis method. The doxorubicin release rate was increased at acidic pH compared with basic pH, indicating that DexPHS nanoparticles have pH-sensitive properties and that drug release can be controlled by variations in pH. The antitumor activity of DexPHS nanoparticles incorporating doxorubicin were studied using HuCC-T1 cholangiocarcinoma cells. Viability was decreased in cells treated with nanoparticles at acidic pH, whereas cell viability in response to treatment with doxorubicin did not vary according to changes of pH.
Our results indicated that DexPHS polymeric micelles are promising candidates for antitumor drug targeting.
pH-responsive drug targeting; nanoparticles; block copolymer; poly(L-histidine); dextran
Amino acids stimulate cell growth and suppress autophagy through activation of mTORC1. The activation of mTORC1 by amino acids is mediated by Rag guanosine triphosphatase (GTPase) heterodimers on the lysosome. The molecular mechanism by which amino acids regulate the Rag GTPase heterodimers remains to be elucidated. Here, we identify SH3BP4 (SH3 domain-binding protein 4) as a binding protein and a negative regulator of Rag GTPase complex. SH3BP4 binds to the inactive Rag GTPase complex through its Src homology 3 (SH3) domain under conditions of amino acid starvation and inhibits the formation of active Rag GTPase complex. As a consequence, the binding abrogates the interaction of mTORC1 with Rag GTPase complex and the recruitment of mTORC1 to the lysosome, thus inhibiting amino acid-induced mTORC1 activation and cell growth and promoting autophagy. These results demonstrate that SH3BP4 is a negative regulator of the Rag GTPase complex and amino acid-dependent mTORC1 signaling.
The aim of this study was to investigate the effect of the combination of vorinostat and epigallocatechin-3-gallate against HuCC-T1 human cholangiocarcinoma cells. A novel chemotherapy strategy is required as cholangiocarcinomas rarely respond to conventional chemotherapeutic agents. Both vorinostat and EGCG induce apoptosis and suppress invasion, migration, and angiogenesis of tumor cells. The combination of vorinostat and EGCG showed synergistic growth inhibitory effects and induced apoptosis in tumor cells. The Bax/Bcl-2 expression ratio and caspase-3 and -7 activity increased, but poly (ADP-ribose) polymerase expression decreased when compared to treatment with each agent alone. Furthermore, invasion, matrix metalloproteinase (MMP) expression, and migration of tumor cells decreased following treatment with the vorinostat and EGCG combination compared to those of vorinostat or EGCG alone. Tube length and junction number of human umbilical vein endothelial cells (HUVECs) decreased as well as vascular endothelial growth factor expression following vorinostat and EGCG combined treatment. These results indicate that the combination of vorinostat and EGCG had a synergistic effect on inhibiting tumor cell angiogenesis potential. We suggest that the combination of vorinostat and EGCG is a novel option for cholangiocarcinoma chemotherapy.
5-Aminolevulinic acid (ALA)-based photodynamic therapy (PDT) has the potential to kill cancer cells via apoptotic or necrotic signals that are dependent on the generation of intracellular reactive oxygen species (ROS). Celecoxib is an anti-inflammatory drug that induces intracellular ROS generation. We investigated whether the combined application of celecoxib and ALA-PDT improved the efficacy of PDT in human cholangiocarcinoma cells and in tumor bearing mice. In vitro, combined treatment of celecoxib and ALA-PDT increased phototoxicity and intracellular ROS levels after irradiation with 0.75 J/cm2 when compared to ALA-PDT alone. Even though ROS levels increased with 0.25 J/cm2 of irradiation, it did not influence phototoxicity. When heme oxygenase-1, a defensive protein induced by oxidative stress, was inhibited in the combined treatment group, phototoxicity was increased at both 0.25 J/cm2 and 0.75 J/cm2 of irradiation. We identified the combined effect of ALA-PDT and celecoxib through the increase of oxidative stress such as ROS. In vivo, about 40% tumor growth inhibition was observed with combined application of ALA-PDT and celecoxib when compared to ALA-PDT alone. The combined application of ALA-PDT and celecoxib could be an effective therapy for human cholangiocarcinoma. Moreover, use of a heme oxygenase-1 inhibitor with PDT could play an important role for management of various tumors involving oxidative stress.
celecoxib; aminolevulinic acid; reactive oxygen species; photodynamic therapy; human cholangiocarcinoma
The prognosis of acute lung injury (ALI) after pneumonectomy is poor, with reported mortality rates of 30-100%. Neutrophil elastase inhibitor (NEI) is known to prevent lung injury caused by neutrophil elastase and improve lung function in ALI. We evaluated the effect of NEI on ALI after pneumonectomy.
We analyzed nine patients who required ventilator care due to ALI after pneumonectomy. Five of these patients underwent conventional ventilator care (group I), and four patients underwent ventilator care and were administrated NEI (group II). We retrospectively analyzed the lung injury score (LIS) for 10 days after intubation.
The LIS before intubation satisfied the diagnostic criteria of ALI or acute respiratory distress syndrome (ARDS) in all patients. After intubation, the LIS improved in both groups. But, as times went on, the mean value of the LIS in group II was lower compared to group I. In group I, only one patient underwent extubation. In group II, extubation was possible in three patients. Mortality rates were 80% in group I and 25% in group II.
We conclude that NEI may improve the lung function, shorten the duration of mechanical ventilation, and reduce mortality in patients with ALI after pneumonectomy.
Background and Purpose
Dopamine agonists are first-line drugs for treating the symptoms of restless legs syndrome (RLS). However, few studies have investigated the effect of dopamine agonists on the quality of life (QoL) in RLS patients. We conducted a study to determine whether ropinirole exerts positive effects on the QoL in RLS patients and to analyze the underlying factors.
Primary RLS patients from eight medical centers were recruited in the study. They were evaluated in the baseline phase using various questionnaires including the Korean versions of the International Restless Legs Scale (K-IRLS), RLS QoL questionnaire (K-RLSQoL), and the Short Form 36 Health Survey (SF-36). After taking ropinirole for 8 weeks the same questionnaires were again completed as a re-evaluation. We analyzed the statistical difference using a paired t-test, a Pearson's correlation, and a stepwise multiple regression in order to identify the factors associated with the QoL change.
A total of 107 subjects, including 65 (60.7%) females, completed this study. They were aged 51.68±14.80 years (mean±SD) and had a symptom duration of 8.8±9.0 months. After treatment with ropinirole, there were significant improvements on the K-RLSQoL, SF-36, and K-IRLS. The Pearson's correlation analysis showed that the improvement of QoL in RLS patients was significantly correlated with the severity of RLS (r=0.236, p<0.014) at baseline.
The results from this study suggest that treatment with ropinirole can improve the QoL in RLS patients. The improvement in the QoL is more related with the improvement of RLS symptoms.
restless legs syndrome; dopamine agonists; quality of life; sleep
Autophagy, the primary recycling pathway of cells, plays a critical role in mitochondrial quality control under normal growth conditions and in the response to cellular stress. The Hsp90-Cdc37 chaperone complex coordinately regulates the activity of select kinases to orchestrate many facets of the stress response. Although both maintain mitochondrial integrity, the relationship between Hsp90-Cdc37 and autophagy has not been well characterized. Ulk1, one of the mammalian homologues of yeast Atg1, is a serine-threonine kinase required for mitophagy. Here we show that the interaction between Ulk1 and Hsp90-Cdc37 stabilizes and activates Ulk1, which in turn is required for the phosphorylation and release of Atg13 from Ulk1, and for the recruitment of Atg13 to damaged mitochondria. Hsp90-Cdc37, Ulk1 and Atg13 phosphorylation are all required for efficient mitochondrial clearance. These findings establish a direct pathway that integrates Ulk1- and Atg13- directed mitophagy with the stress response coordinated by Hsp90 and Cdc37.
Oxidative stress such as reactive oxygen species (ROS) within the inflamed joint have been indicated as being involved as inflammatory mediators in the induction of arthritis. Correlations between extracellular-superoxide dismutase (EC-SOD) and inflammatory arthritis have been shown in several animal models of RA. However, there is a question whether the over-expression of EC-SOD on arthritic joint also could suppress the progression of disease or not. In the present study, the effect on the synovial tissue of experimental arthritis was investigated using EC-SOD over-expressing transgenic mice. The over-expression of EC-SOD in joint tissue was confirmed by RT-PCR and immunohistochemistry. The degree of the inflammation in EC-SOD transgenic mice was suppressed in the collagen-induced arthritis model. In a cytokine assay, the production of pro-inflammatory cytokines such as, IL-1β, TNFα, and matrix metalloproteinases (MMPs) was decreased in fibroblast-like synoviocyte (FLS) but not in peripheral blood. Histological examination also showed repressed cartilage destruction and bone in EC-SOD transgenic mice. In conclusion, these data suggest that the over-expression of EC-SOD in FLS contributes to the activation of FLS and protection from joint destruction by depressing the production of the pro-inflammatory cytokines and MMPs. These results provide EC-SOD transgenic mice with a useful animal model for inflammatory arthritis research.
arthritis, experimental; reactive oxygen species; rheumatoid arthritis; superoxide dismutase; synovial membrane
High normal values of urine albumin-to-creatinine ratio (UACR) have been reported to have predictive values for hypertension, incident stroke, and higher mortality in the general population. This study aimed to investigate the association between normal ranges of UACR and carotid intima-media thickness (CIMT) in adult population.
We performed a cross-sectional study in adults aged 45 to 74 years who were living in Namwon City, South Korea. Both common CIMTs were measured, and mean values were calculated. Normal values of UACR were defined as <30mg/g and categorized into quintiles; less than 6.50, 6.51-9.79, 9.80-13.49, 13.50-18.89, and more than 18.90 mg/g. The association between the quintiles of UACR and common CIMT was analyzed and stratified by sex.
A total of 7555 participants (3084 men and 4471 women) with normal UACR were enrolled in the present study. Common CIMT was positively and independently associated with increasing quintiles of UACR in men and women, even after adjusting for potential confounders including age and cardiovascular risk factors. Compared to the first quintile, the fifth quintile showed odds ratios of 1.80 (95% confidence intervals, 1.26-2.55) and 1.97 (1.28-3.04) for increased CIMT (>0.9mm) in men and women, respectively.
Higher UACR values within normal ranges (<30 mg/g) were positively and independently associated with CIMT in a Korean general population, suggesting that higher normal values of UACR might be a risk marker of subclinical carotid atherosclerosis.
Albuminuria; Atherosclerosis; Carotid intima-media thickness; Urine albumin-to-creatinine ratio
Endoscopic thoracic sympathetic surgery is effective for treating palmar hyperhidrosis, although compensatory sweating (CS) is a significant and annoying side effect. The purpose of this study was to compare the results of limited resection at two different locations.
From May 2004 to June 2009, T3 sympathicotomy (group I) was performed in 46 patients and T3,4 ramicotomy (group II) was performed in 43 patients during the same period. T3 sympathicotomy (group I) and T3,4 ramicotomy (group II) were performed during the same period. Using questionnaires, completed by the patients, the satisfaction rates and grades of CS were analyzed.
No significant differences in age distribution or sex ratios were observed between the two groups. The satisfaction rate was 91.3 % in group I and 79.1 % in group II. The operation time was 19.8 (±6.6) min in group I, and 51.6 (±18.8) min in group II, showing a statistically significant difference (p < 0.002). The incidence of persistent hand sweating in group II (16.3 %) was higher than that observed in group I (2.2 %). The incidence of compensatory sweating on the lower extremities was higher in group II (37.2 %) than in group I (10.9 %).
Although ramicotomy is considered to be an effective method for treating hyperhidrosis and has a theoretical advantage of allowing greater anatomical resection, it requires longer operation time and induces more severe compensatory sweating in the lower limbs resulting in reduced satisfaction rates.
Palmar hyperhidrosis; Compensatory sweating
Protein tyrosine phosphatases act as key regulators in differentiation-associated signaling pathways. It is proposed that RPTPμ acts as a positive regulator of adipogenesis by modulating the cytoplasmic p120 catenin level.
Adipocyte differentiation can be regulated by the combined activity of protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs). In particular, PTPs act as key regulators in differentiation-associated signaling pathways. We recently found that receptor-type PTPμ (RPTPμ) expression is markedly increased during the adipogenic differentiation of 3T3-L1 preadipocytes and mesenchymal stem cells. Here, we investigate the functional roles of RPTPμ and the mechanism of its involvement in the regulation of signal transduction during adipogenesis of 3T3-L1 cells. Depletion of endogenous RPTPμ by RNA interference significantly inhibited adipogenic differentiation, whereas RPTPμ overexpression led to an increase in adipogenic differentiation. Ectopic expression of p120 catenin suppressed adipocyte differentiation, and the decrease in adipogenesis by p120 catenin was recovered by introducing RPTPμ. Moreover, RPTPμ induced a decrease in the cytoplasmic p120 catenin expression by reducing its tyrosine phosphorylation level, consequently leading to enhanced translocation of Glut-4 to the plasma membrane. On the basis of these results, we propose that RPTPμ acts as a positive regulator of adipogenesis by modulating the cytoplasmic p120 catenin level. Our data conclusively demonstrate that differentiation into adipocytes is controlled by RPTPμ, supporting the utility of RPTPμ and p120 catenin as novel target proteins for the treatment of obesity.
Sorafenib-incoporated nanoparticles were prepared using a block copolymer that is composed of dextran and poly(DL-lactide-co-glycolide) [DexbLG] for antitumor drug delivery. Sorafenib-incorporated nanoparticles were prepared by a nanoprecipitation-dialysis method. Sorafenib-incorporated DexbLG nanoparticles were uniformly distributed in an aqueous solution regardless of the content of sorafenib. Transmission electron microscopy of the sorafenib-incorporated DexbLG nanoparticles revealed a spherical shape with a diameter < 300 nm. Sorafenib-incorporated DexbLG nanoparticles at a polymer/drug weight ratio of 40:5 showed a relatively uniform size and morphology. Higher initial drug feeding was associated with increased drug content in nanoparticles and in nanoparticle size. A drug release study revealed a decreased drug release rate with increasing drug content. In an in vitro anti-proliferation assay using human cholangiocarcinoma cells, sorafenib-incorporated DexbLG nanoparticles showed a similar antitumor activity as sorafenib. Sorafenib-incorporated DexbLG nanoparticles are promising candidates as vehicles for antitumor drug targeting.
sorafenib; polymeric micelle; dextran; poly(DL-lactide-co-glycolide)
Polymeric micelles using amphiphilic macromolecules are promising vehicles for antitumor targeting. In this study, we prepared anticancer agent-incorporated polymeric micelles using novel block copolymer.
We synthesized a block copolymer composed of dextran and poly (DL-lactide-co-glycolide) (DexbLG) for antitumor drug delivery. Doxorubicin was selected as the anticancer drug, and was incorporated into polymeric micelles by dialysis. Polymeric micelles were observed by transmission electron microscopy to be spherical and smaller than 100 nm, with a narrow size distribution. The particle size of doxorubicin-incorporated polymeric micelles increased with increasing drug content. Higher initial drug feeding also increased the drug content.
During the drug-release study, an initial burst release of doxorubicin was observed for 10 hours, and doxorubicin was continuously released over 4 days. To investigate the in vitro anticancer effects of the polymeric micelles, doxorubicin-resistant HuCC-T1 cells were treated with a very high concentration of doxorubicin. In an antiproliferation study, the polymeric micelles showed higher cytotoxicity to doxorubicin-resistant HuCC-T1 cells than free doxorubicin, indicating that the polymeric micelles were effectively engulfed by tumor cells, while free doxorubicin hardly penetrated the tumor cell membrane. On confocal laser scanning microscopy, free doxorubicin expressed very weak fluorescence intensity, while the polymeric micelles expressed strong red fluorescence. Furthermore, in flow cytometric analysis, fluorescence intensity of polymeric micelles was almost twice as high than with free doxorubicin.
DexbLG polymeric micelles incorporating doxorubicin are promising vehicles for antitumor drug targeting.
dextran; polymeric micelle; block copolymer; poly(DL-lactide-co-glycolide)
Cancer cells have been reported to exhibit an enhanced capacity for protoporphyrin IX (PpIX) synthesis facilitated by the administration of 5-aminolevulinic acid (ALA). We investigated the effect of ALA-based photodynamic therapy (PDT) on human cholangiocarcinoma cells (HuCC-T1). Since protoporphyrin IX (PpIX), a metabolite of ALA, can produce reactive oxygen species (ROS) under irradiation and then induce phototoxicity, ALA-based PDT is a promising candidate for the treatment of cholangiocarcinoma. When various concentrations of ALA (0.05–2 mM) were used to treat HuCC-T1 cells for 6 or 24 hours, the intracellular PpIX level increased according to the ALA concentration and treatment time. Furthermore, an increased amount of PpIX in HuCC-T1 cells induced increased production of ROS by irradiation, resulting in increased phototoxicity.
ALA-based photodynamic therapy; HuCC-T1; protoporphyrin IX; ROS
The preoperative detection of emphysema like changes (ELCs) is necessary for the successful treatment of pneumothorax. High resolution computed tomography (HRCT) has been used for the preoperative detection of ELCs. However, the traditional HRCT method uses only the axial view, which is perpendicular to the distribution of ELCs. This is not an ideal diagnostic method for the evaluation of ELCs.
Forty-eight patients with pneumothorax had multi-detector computed tomography (MDCT) reconstruction using the coronal view. ELCs were evaluated in the axial and coronal view by a radiologist. A surgeon performed intra-operative examinations of the ELCs. The sensitivity of the different views was compared.
The detection sensitivity was 74.4% (70/94) for the axial view and 91.5% (86/94) for the axial-coronal combined view. The intra-operative detection rate was 95.7% (90/94). The preoperative detection of ELCs on the axial-coronal combined view was significantly higher than on the conventional axial view alone (p < 0.01).
Evaluation of ELCs on the axial and coronal combined HRCT improved the sensitivity of preoperative detection of ELCs compared to the conventional single axial HRCT. This increased sensitivity will help decrease the recurrence with VATS.
The mammalian target of rapamycin complex 1 (mTORC1) is a molecular hub that regulates protein synthesis in response to a number of extracellular stimuli. Cyclic AMP (cAMP) is considered to be an important second messenger that controls mTOR; however, the signaling components of this pathway have not yet been elucidated. Here, we identify cAMP phosphodiesterase 4D (PDE4D) as a binding partner of Rheb that acts as a cAMP-specific negative regulator of mTORC1. Under basal conditions, PDE4D binds Rheb in a noncatalytic manner that does not require its cAMP-hydrolyzing activity and thereby inhibits the ability of Rheb to activate mTORC1. However, elevated cAMP levels disrupt the interaction of PDE4D with Rheb and increase the interaction between Rheb and mTOR. This enhanced Rheb-mTOR interaction induces the activation of mTORC1 and cap-dependent translation, a cellular function of mTORC1. Taken together, our results suggest a novel regulatory mechanism for mTORC1 in which the cAMP-determined dynamic interaction between Rheb and PDE4D provides a key, unique regulatory event. We also propose a new role for PDE4 as a molecular transducer for cAMP signaling.
Inflammatory cells are known to be associated with the progression of atherosclerosis and plaque rupture. However, the relation to inflammatory cells and apolipoproteins on the progression of atherosclerosis is unknown. This study was aimed at examining the different expressions of inflammatory cells and evaluate the effect of apolipoprotein (APO) C1 and APO E during the progression of atherosclerosis.
Ten atherosclerotic tissues were compared with five non-atherosclerotic tissues. The presence of vascular smooth muscle cells (VSMCs), macrophages, T-cells, APO C1, and APO E were identified by Western blotting and immunohistochemical analysis with antibodies. The senescence was analyzed by senescence-associated β-galactosidase.
The protein expression and senescence of macrophages, APO C1 and APO E were significantly higher in the main atherosclerotic lesion than the non-atherosclerotic lesion. A high concentration of inflammatory cells and the paucity of VSMCs were present in the shoulder area. In addition, macrophage and T-cells are expressed in the early stage of atherosclerotic development and more expanded in advanced atherosclerotic plaques. APO C1 was expressed mainly within the necrotic core, and APO E existed mostly around the necrotic core and the fibrous cap in advanced atherosclerotic plaques.
Our study indicated that the expression and the senescence of macrophage and T-cells may be closelyrelated to induction and deposition of APO C1 and APO E. This contributes to the development and progression of atherosclerotic plaque by expanding the necrotic core.
Atherosclerosis; Inflammatory cells; Apolipoproteins; Senescence
Papillary thyroid cancer (PTC) is the most common malignancy of the thyroid gland. It involves several molecular mechanisms. The BRAF V600E mutation has been identified as the most common genetic abnormality in PTC. Moreover, it is known to be more prevalent in Korean PTC patients than in patients from other countries. We investigated distinct genetic profiles in Korean PTC through cDNA microarray analysis.
Transcriptional profiles of five PTC samples and five paired normal thyroid tissue samples were generated using cDNA microarrays. The tumors were genotyped for BRAF mutations. The results of the cDNA microarray gene expression analysis were confirmed by real-time PCR and immunohistochemistry analysis of 35 PTC patients.
Four of the five patients whose PTC tissues were subjected to microarray analysis were found to carry the BRAF V600E mutation. Microarrays analysis of the five PTC tissue samples showed the expression of 96 genes to be increased and that of 16 genes decreased. Real-time reverse transcription-polymerase chain reaction (RT-PCR) confirmed increased expression of SLC34A2, TM7SF4, COMP, KLK7, and KCNJ2 and decreased expression of FOXA2, SLC4A4, LYVE-1, and TFCP2L1 in PTC compared with normal tissue. Of these genes, TFCP2L1, LYVE-1, and KLK7 were previously unidentified in PTC microarray analysis. Notably, Foxa2 activity in PTC was reduced, as shown by its cytoplasmic localization, in immunohistochemical analyses.
These findings demonstrate both similarities and differences between our results and previous reports. In Korean cases of PTC, Foxa2 activity was reduced with its cytoplasmic accumulation. Further studies are needed to confirm the relationship between FOXA2 and BRAF mutations in Korean cases of PTC.
BRAF mutation; Oligonucleotide array sequence analysis; FOXA2 protein, human; Thyroid cancer
The mammalian target of rapamycin (mTOR) interacts with raptor to form the protein complex mTORC1 (mTOR complex 1), which plays a central role in the regulation of cell growth in response to environmental cues. Given that glucose is a primary fuel source and a biosynthetic precursor, how mTORC1 signaling is coordinated with glucose metabolism has been an important question. Here, we found that the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) binds Rheb and inhibits mTORC1 signaling. Under low-glucose conditions, GAPDH prevents Rheb from binding to mTOR and thereby inhibits mTORC1 signaling. High glycolytic flux suppresses the interaction between GAPDH and Rheb and thus allows Rheb to activate mTORC1. Silencing of GAPDH or blocking of the Rheb-GAPDH interaction desensitizes mTORC1 signaling to changes in the level of glucose. The GAPDH-dependent regulation of mTORC1 in response to glucose availability occurred even in TSC1-deficient cells and AMPK-silenced cells, supporting the idea that the GAPDH-Rheb pathway functions independently of the AMPK axis. Furthermore, we show that glyceraldehyde-3-phosphate, a glycolytic intermediate that binds GAPDH, destabilizes the Rheb-GAPDH interaction even under low-glucose conditions, explaining how high-glucose flux suppresses the interaction and activates mTORC1 signaling. Taken together, our results suggest that the glycolytic flux regulates mTOR's access to Rheb by regulating the Rheb-GAPDH interaction, thereby allowing mTORC1 to coordinate cell growth with glucose availability.