Brain-specific glycosylation enzyme GnT-IX maintains levels of protein tyrosine phosphatase receptor PTPRZ, thereby mediating glioma growth.

Gliomas are the most prevalent primary tumor of the central nervous system. Despite advances in imaging technologies, neurosurgical techniques, and radiotherapy, a cure for high-grade glioma remains elusive. Several groups have reported that protein tyrosine phosphatase receptor type Z (PTPRZ) is highly expressed in glioblastoma, and that targeting PTPRZ attenuates tumor growth in mice. PTPRZ is modified with diverse glycan, including the PTPRZ-unique human natural killer-1 capped O-mannosyl core M2 glycans. However, the regulation and function of these unique glycans are unclear. Using CRISPR genome-editing technology, we first demonstrated that disruption of the PTPRZ gene in human glioma LN-229 cells resulted in profoundly reduced tumor growth in xenografted mice, confirming the potential of PTPRZ as a therapeutic target for glioma. Furthermore, multiple glycan analyses revealed that PTPRZ derived from glioma patients and from xenografted glioma expressed abundant levels of human natural killer-1-capped O-Man glycans via extrinsic signals. Finally, since deficiency of O-Man core M2 branching enzyme N-acetylglucosaminyltransferase IX (GnT-IX) was reported to reduce PTPRZ protein levels, we disrupted the GnT-IX gene in LN-229 cells and found a significant reduction of glioma growth both in vitro and in the xenograft model. These results suggest that the PTPR glycosylation enzyme GnT-IX may represent a promising therapeutic target for glioma.

O-GalNAc glycosylation determines intracellular trafficking of APP and Aß production.

A primary pathology of Alzheimer's disease (AD) is amyloid ß (Aß) deposition in brain parenchyma and blood vessels, the latter being called cerebral amyloid angiopathy (CAA). Parenchymal amyloid plaques presumably originate from neuronal Aß precursor protein (APP). Although vascular amyloid deposits' origins remain unclear, endothelial APP expression in APP knock-in mice was recently shown to expand CAA pathology, highlighting endothelial APP's importance. Furthermore, two types of endothelial APP-highly O-glycosylated APP and hypo-O-glycosylated APP-have been biochemically identified, but only the former is cleaved for Aß production, indicating the critical relationship between APP O-glycosylation and processing. Here, we analyzed APP glycosylation and its intracellular trafficking in neurons and endothelial cells. Although protein glycosylation is generally believed to precede cell surface trafficking, which was true for neuronal APP, we unexpectedly observed that hypo-O-glycosylated APP is externalized to the endothelial cell surface and transported back to the Golgi apparatus, where it then acquires additional O-glycans. Knockdown of genes encoding enzymes initiating APP O-glycosylation significantly reduced Aß production, suggesting this non-classical glycosylation pathway contributes to CAA pathology and is a novel therapeutic target.

Usefulness of pancreatic volume quantitative analysis as a predictor of development and severity in post-endoscopic retrograde cholangiopancreatography pancreatitis.

BACKGROUND: Post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP) is one of the most common and serious adverse events associated with ERCP. Thus, we aimed to investigate the usefulness of pre-ERCP pancreatic volume, which is deeply involved in exocrine pancreatic function, as a predictor of PEP development and severity. METHODS: In total, 1107 patients who underwent their first ERCP were recruited from January 2012 to December 2022 for this retrospective study. Pancreatic volume was measured by cross-sectional analysis using pre-ERCP computed tomography images. The potential risk factors for PEP were analyzed using multivariate logistic regression. RESULTS: Of the 745 patients included in the study, 34 (4.6 %) developed PEP: severe, moderate, or mild PEP in 1, 7, and 26 cases, respectively. Multivariate analysis revealed that only a large pancreatic volume (>70 cm3) was an independent risk factor for the development of PEP (odds ratio, 7.98; 95 % confidence interval, 11.80-67.50; P < 0.001). Additionally, the incidence of PEP was significantly higher in patients with a pancreatic volume >70 cm3 than in those with a pancreatic volume ≤70 cm3 (18.5 % [31/168] vs. 0.5 % [3/577]; P < 0.001). Also, the association between the pre-ERCP pancreatic volume and PEP severity was positively correlated (r = 0.625, P < 0.005), with a larger pancreatic volume corresponding to increased PEP severity. CONCLUSIONS: A large pancreatic volume before ERCP may be a novel risk factor for PEP incidence and severity. This finding suggests that quantitative analysis of the pre-ERCP pancreatic volume could be a useful predictor of PEP.

Brain-specific glycosylation of protein tyrosine phosphatase receptor type Z (PTPRZ) marks a demyelination-associated astrocyte subtype.

Astrocytes are the most abundant glial cell type in the brain, where they participate in various homeostatic functions. Transcriptomically, diverse astrocyte subpopulations play distinct roles during development and disease progression. However, the biochemical identification of astrocyte subtypes, especially by membrane surface protein glycosylation, remains poorly investigated. Protein tyrosine phosphatase receptor type zeta (PTPRZ) is a highly expressed membrane protein in CNS glia cells that can be modified with diverse glycosylation, including the unique HNK-1 capped O-mannosyl (O-Man) core M2 glycan mediated by brain-specific branching enzyme GnT-IX. Although PTPRZ modified with HNK-1 capped O-Man glycans (HNK-1-O-Man+ PTPRZ) is increased in reactive astrocytes of demyelination model mice, whether such astrocytes emerge in a broad range of disease-associated conditions or are limited to conditions associated with demyelination remains unclear. Here, we show that HNK-1-O-Man+ PTPRZ localizes in hypertrophic astrocytes of damaged brain areas in patients with multiple sclerosis. Furthermore, we show that astrocytes expressing HNK-1-O-Man+ PTPRZ are present in two demyelination mouse models (cuprizone-fed mice and a vanishing white matter disease model), while traumatic brain injury does not induce glycosylation. Administration of cuprizone to Aldh1l1-eGFP and Olig2KICreER/+ ;Rosa26eGFP mice revealed that cells expressing HNK-1-O-Man+ PTPRZ are derived from cells in the astrocyte lineage. Notably, GnT-IX but not PTPRZ mRNA was up-regulated in astrocytes isolated from the corpus callosum of cuprizone model mice. These results suggest that the unique PTPRZ glycosylation plays a key role in the patterning of demyelination-associated astrocytes.

High correlation of hepatic shear wave velocity with esophageal varices complication rate in patients with chronic liver diseases.

BACKGROUND: Histological evaluation by liver biopsy is considered the gold standard for assessing liver disease; however, it is highly invasive. Non-invasive liver stiffness measurement by shear wave elastography (SWE) is effective for evaluating the hepatic fibrosis stage and related diseases. In this study, we investigated the correlations of liver stiffness with hepatic inflammation/fibrosis, functional hepatic reserve, and related diseases in patients with chronic liver disease (CLD). METHODS: Shear wave velocity (Vs) values were measured using point SWE in 71 patients with liver disease from 2017 to 2019. Liver biopsy specimens and serum biomarkers were collected at the same time, and splenic volume was measured using computed tomography images with the software Ziostation2. Esophageal varices (EV) were evaluated by upper gastrointestinal endoscopy. RESULTS: Among CLD-related function and complications, Vs values were highly correlated with liver fibrosis and EV complication rates. The median Vs values for liver fibrosis grades F0, F1, F2, F3, and F4 were 1.18, 1.34, 1.39, 1.80, and 2.12 m/s, respectively. Comparison of receiver operating characteristic (ROC) curves to predict cirrhosis showed that area under the ROC (AUROC) curve for Vs values was 0.902, which was not significantly different from the AUROCs for the FIB-4 index, platelet count, hyaluronic acid, or type IV collagen 7S, while it was significantly different from the AUROC for mac-2 binding protein glycosylation isomer (M2BPGi) (P < 0.01). Comparison of ROC curves to predict EV showed that the AUROC for Vs values was 0.901, which was significantly higher than the AUROCs for FIB-4 index (P < 0.05), platelet count (P < 0.05), M2BPGi (P < 0.01), hyaluronic acid (P < 0.05), and splenic volume (P < 0.05). In patients with advanced liver fibrosis (F3 + F4), there was no difference in blood markers and splenic volume, while Vs value was significantly higher in patients with EV (P < 0.01). CONCLUSIONS: Hepatic shear wave velocity was highly correlated with EV complication rates in chronic liver diseases as compared to blood markers and splenic volume. In advanced CLD patients, Vs values of SWE are suggested to be effective in predicting the appearance of EV noninvasively.

Bipolar-current needle-knife with a water jet function (Jet B-knife) shortens the procedure time of endoscopic submucosal dissection for colorectal tumors.

BACKGROUND: Endoscopic submucosal dissection (ESD) is a technically difficult and time-consuming procedure for the treatment of large colorectal tumors. In Japan, the ball-tip bipolar-current needle-knife (BB-knife) has been used in ESD as a safe device that minimizes the damage to deeper tissues of colorectal neoplasms. In May 2012, a BB-knife combined with a water jet function (Jet B-knife) was newly developed. METHODS: This retrospective study was aimed at examining the effectiveness and safety of the Jet B-knife. The BB-knife was used in 276 lesions (BB-knife group), while the Jet B-knife was used in 245 lesions (Jet B-knife group). We evaluated tumor characteristics and the results of the ESD procedures, including the size of the resected tumor, histological diagnosis, time required for resection, frequency of using other electrical devices, en bloc resection rate, and incidence rate of associated complications. Then, the data obtained were compared between the two groups. RESULTS: The histological evaluation of the resected tumors revealed that the incidence of cancer was not significantly different between the two groups. The median time required for resection was 103 min (45-255) in the BB-knife group and 51 min (28-210) in the Jet B-knife group. The difference was statistically significant (p < 0.05). Furthermore, the median tumor diameters were 23.1 mm (18-50) and 26.2 mm (20-60) in the BB-knife and Jet B-knife groups, respectively, demonstrating a statistically significant difference (p < 0.05). Multivariate logistic regression analysis revealed that short resection time (p < 0.001) and reduced use of hemostatic devices (p < 0.01) were independent favorable features of Jet B-knife. The en bloc resection rate and the perforation rate were not statistically significant between the two groups. CONCLUSIONS: Use of the Jet B-knife may contribute to the development of a time-saving, cost-effective, and safe procedure for ESD of colorectal tumors.

Genetic polymorphism and decreased expression of HLA class II DP genes are associated with HBV reactivation in patients treated with immunomodulatory agents.

Hepatitis B virus (HBV) reactivation can be triggered by immunosuppressive chemotherapy. HLA class II molecules may play a role in HBV reactivation. Genetic polymorphism and mRNA expression of HLA class II were examined in patients with latent HBV infection treated with immunosuppressive therapies. Subjects with resolved HBV infection who had undergone treatment with immunosuppressive chemotherapies were retrospectively enrolled (n = 42) and divided into reactivated (n = 9) and non-reactivated groups (n = 33). Patients were genotyped for 17 single nucleotide polymorphisms (SNPs) within HLA class II DPA1, and DPB1, and mRNA expression levels of HLA class II genes were assessed. The frequency of the AA genotype of rs872956, a SNP in HLA-DPB1, was significantly higher in the reactivated group than in the non-reactivated group (55.6% vs 12.1%, P < 0.05). The frequencies of the T allele and non-AA genotypes (AT/TT) of rs3116996 (located in DPB1) were significantly higher in the reactivated group (T allele frequency: 16.7% vs 0.0% [P < 0.01], non-AA genotype frequency: 22.2% vs 0.0% [P < 0.05]). Multivariate logistic regression identified the AA genotype of rs872956 as an independent protective factor against HBV reactivation (odds ratio [OR] = 18.1, 95% confidence interval [CI] = 2.6-126.7, P < 0.01). mRNA expression of HLA-DPB1 was lower in the HBV reactivated group than in the non-reactivated group (median 276.1 ± 165.6/ß-actin vs 371.4 ± 407.5/ß-actin [P < 0.05]). These results suggest the involvement of HLA class II molecules in HBV reactivation after treatment with immunomodulatory agents.

Quantitative distinction of the morphological characteristic of erythrocyte precursor cells with texture analysis using gray level co-occurrence matrix.

BACKGROUND: Morphological characteristics of blood cells are still qualitatively defined. So a texture analysis (Tx) method using gray level co-occurrence matrices (GLCMs; CM-Tx method) was applied to images of erythrocyte precursor cells (EPCs) for quantitatively distinguishing four types of EPC stages: proerythroblast, basophilic erythroblast, polychromatic erythroblast, and orthochromatic erythroblast. METHODS: Fifty-five images of four types of EPCs were downloaded from an atlas uploaded by the Blood Cell Morphology Standardization Subcommittee (BCMSS) of the Japanese Society of Laboratory Hematology (JSLH). Using in-house programs, two types of GLCMs-(R: d=1, θ=0°) and (U: d=1, θ=270°)-and nine types of texture distinction index (TDI) were calculated with images removed outer part of cell. RESULTS: Three binary decision trees were sequentially divided among four types of EPC with the sum average of GLCM (U), the contrast of GLCM (R), and the sum average of GLCM (U). The average concordance rate (sensitivity) of CM-Tx method with the judgments of eleven experts in the BCMSS of the JSLH was 95.8% (87.5-100.0), and the average specificity was 97.6% (92.5-100.0). CONCLUSIONS: The CM-Tx method is an effective tool for quantitative distinction of EPC with their morphological features.

Identification of novel variants in HLA class II region related to HLA DPB1 expression and disease progression in patients with chronic hepatitis C.

Recent genome-wide studies have demonstrated that HLA class II gene may play an important role in viral hepatitis. We studied genetic polymorphism and RNA expression of HLA class II genes in HCV-related liver diseases. The study was performed in groups consisting of 24 patients with HCV-related liver disease (12 of persistent normal ALT: PNALT group and 12 of advanced liver disease: ALD group) and 26 patients without HCV infection (control group). In PBMC samples, RNA expression of HLA class II genes (HLA-DPA1, DPB1, DQA1, DQB1, and DRB1) was analyzed by real-time RT-PCR. Furthermore, 22 single nucleotide polymorphisms (SNPs) in HLA class II gene and two SNPs in IL28B gene were genotyped by genetic analyzer (GENECUBE®). In expression analysis, only DPB1 level was significantly different. Mean expression level of DPB1gene in control group was 160.0, PNALT group 233.8, and ALD group 465.0 (P < 0.01). Of 24 SNPs, allele frequencies were statistically different in two SNPs (rs2071025 and rs3116996) between PNALT groups and ALD group (P < 0.01). In rs2071025, TT genotype was frequently detected in ALD group and expression level was significantly higher than the other genotypes (449.2 vs 312.9, P < 0.01). In rs3116996, TA or TT (non AA) genotype was frequently detected in ALD group and expression level was significantly higher than genotype AA (457.1 vs 220.9, P < 0.01). Genotyping and expression analysis in HLA class II gene revealed that two SNPs of HLA-DPB1 (rs2071025 and rs3116996) were significantly correlated to RNA expression and progression of HCV-related liver diseases.

Multi-point temperature sensing using a linear-cavity lasing system.

A multi-point fiber sensing system formed from a linear cavity laser is proposed. Various optical sensing systems have been investigated, for example, using fiber Bragg grating (FBG) and Brillouin scattering for multi-point sensing. This paper focuses on a simple sensing system by using multi-wavelength lasing with parallel cavities and a semiconductor optical amplifier (SOA). First, optical nonlinearity in amplification of the SOA is discussed to clarify the effects of gain saturation and four-wave mixing on the proposed multi-channel sensing system. And then lasing conditions in the linear cavity laser consisting of an SOA, an arrayed waveguide grating (AWG), and FBGs are theoretically investigated. The multi-wavelength lasing power is found to be limited mainly by gain saturation in the SOA. The lasing power for the eight-channel system is evaluated to be -8.5 dBm when the total loss in the linear cavity is 10 dB. The lasing power can be increased by 3 dB when the channel number is decreased to four. Next, multi-wavelength lasing in the cavity consisting of an SOA, an AWG, a loop mirror, and fiber mirror reflectors is experimentally demonstrated up to eight channels. Finally, two-channel temperature sensing ranging from 13°C to 76°C is experimentally confirmed by using two FBGs as the sensing elements with an AWG having 100-GHz bandwidth.

The Novel Mechanisms Concerning the Inhibitions of Palmitate-Induced Proinflammatory Factor Releases and Endogenous Cellular Stress with Astaxanthin on MIN6 ß-Cells.

Astaxanthin, an antioxidant agent, can protect pancreatic ß-cells of db/db mice from glucotoxicity and resolve chronic inflammation in adipose tissue. Nonetheless, the effects of astaxanthin on free-fatty-acid-induced inflammation and cellular stress in ß-cells remain to be demonstrated. Meanwhile, palmitate enhances the secretion of pro-inflammatory adipokines monocyte chemoattractant protein-1 (MCP-1) and VEGF120 (vascular endothelial growth factor). We therefore investigated the influence of astaxanthin on palmitate-stimulated MCP-1 and VEGF120 secretion in mouse insulinoma (MIN6) pancreatic ß-cells. Furthermore, whether astaxanthin prevents cellular stress in MIN6 cells was also assessed. Pre-treatment with astaxanthin or with N-acetyl-cysteine (NAC) which is an antioxidant drug, significantly attenuated the palmitate-induced MCP-1 release through downregulation of phosphorylated c-Jun NH2-terminal protein kinase (JNK) pathways, and suppressed VEGF120 through the PI3K/Akt pathways relative to the cells stimulated with palmitate alone. In addition, palmitate significantly upregulated homologous protein (CHOP) and anti-glucose-regulated protein (GRP78), which are endoplasmic reticulum (ER) stress markers, in MIN6 cells. On the other hand, astaxanthin attenuated the increased CHOP content, but further up-regulated palmitate-stimulated GRP78 protein expression. By contrast, NAC had no effects on either CHOP or GRP78 enhancement induced by palmitate in MIN6 cells. In conclusion, astaxanthin diminishes the palmitate-stimulated increase in MCP-1 secretion via the downregulation of JNK pathways in MIN6 cells, and affects VEGF120 secretion through PI3K/Akt pathways. Moreover, astaxanthin can prevent not only oxidative stress caused endogenously by palmitate but also ER stress, which NAC fails to attenuate, via upregulation of GRP78, an ER chaperon.

Ghrelin augments the expressions and secretions of proinflammatory adipokines, VEGF120 and MCP-1, in differentiated 3T3-L1 adipocytes.

Ghrelin is a physiological-active peptide with growth hormone-releasing activity, orexigenic activity, etc. In addition, the recent study has also suggested that ghrelin possesses the pathophysiological abilities related with type 2 diabetes. However, the ghrelin-direct-effects implicated in type 2 diabetes on peripheral tissues have been still unclear, whereas its actions on the central nervous system (CNS) appear to induce the development of diabetes. Thus, to assess its peripheral effects correlated with diabetes, we investigated the regulatory mechanisms about adipokines, which play a central role in inducing peripheral insulin resistance, secreted from mature 3T3-L1 adipocytes stimulated with ghrelin in vitro . The stimulation with 50 nmol/L ghrelin for 24 h resulted in the significant 1.9-fold increase on vascular endothelial growth factor-120 (VEGF(120)) releases (p < 0.01) and the 1.7-fold on monocyte chemoattractant protein-1 (MCP-1) (p < 0.01) from 3T3-L1 adipocytes, respectively, while ghrelin failed to enhance tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), IL-6, IL-10 and adiponectin secretions. In addition, Akt phosphorylation on Ser473 and c-Jun NH2 -terminal protein kinase (JNK) phosphorylation on Thr183/Tyr185 were markedly enhanced 1.4-fold (p < 0.01) and 1.6-fold (p < 0.01) in the ghrelin-stimulated adipocytes, respectively. Furthermore, the treatment with LY294002 (50 µmol/L) and Wortmannin (10nmol/L), inhibitors of phosphatidylinositol 3-kinase (PI3K), significantly decreased the amplified VEGF(120) secretion by 29% (p < 0.01) and 28% (p < 0.01) relative to the cells stimulated by ghrelin alone, respectively, whereas these inhibitors had no effects on increased MCP-1 release. On the other hand, JNK inhibitor SP600125 (10 µmol/L) clearly reduced the increased MCP-1, but not VEGF(120), release by 35% relative to the only ghrelin-stimulated cells (p < 0.01). In conclusion, ghrelin can enhance the secretions of proinflammatory adipokines, VEGF(120) and MCP-1, but fails to affect IL-10 and adiponectin which are considered to be anti-inflammatory adipokines. Moreover, this augmented VEGF(120) release is invited through the activation of PI3K pathways and the MCP-1 is through JNK pathways. Consequently, our results strongly suggest that ghrelin can induce the development of diabetes via its direct-action in peripheral tissues as well as via in CNS.

Pituitary metastasis of hepatocellular carcinoma presenting with panhypopituitarism: a case report.

BACKGROUND: Metastasis to the pituitary gland is extremely rare and is often detected incidentally by symptoms associated with endocrine dysfunction. Breast and lung cancer are the most common primary metastasizing to pituitary gland. Metastasis from hepatocellular carcinoma to the pituitary gland is extremely rare, with only 10 cases having been previously reported. We present here the first case of pituitary metastasis of hepatocellular carcinoma presenting with panhypopituitarism diagnosed by magnetic resonance imaging. CASE PRESENTATION: We report the case of an 80-year-old Japanese woman who presented with the sudden onset of hypotension and bradycardia after having previously been diagnosed with hepatocellular carcinoma. Based on low levels of pituitary hormones, she was diagnosed with panhypopituitarism caused by metastasis of the hepatocellular carcinoma to the pituitary gland. Magnetic resonance imaging with arterial spin-labeling was effective in the differential diagnosis of the intrasellar tumor. The patient died despite hormone replacement therapy because of hypovolemic shock. CONCLUSION: Metastasis to the pituitary gland causes various non-specific symptoms, so it is difficult to diagnose. The present case emphasizes the importance of diagnostic imaging in identifying these metastases. Clinicians should consider the possibility of pituitary metastasis in patients with malignant tumors who demonstrate hypopituitarism.

The association between impaired proinsulin processing and type 2 diabetes mellitus in non-obese Japanese individuals.

We aimed to examine the association between impaired proinsulin processing in pancreatic beta cells and type 2 diabetes mellitus in non-obese Japanese patients. Participants were divided into groups for normal glucose tolerance, prediabetes, and type 2 diabetes based on the oral glucose tolerance test (OGTT). Activities of prohormone convertase (PC) 1/3 and PC2 in fasting states were estimated. Multiple regression analysis was undertaken to ascertain if alteration of the activities of these enzymes contributes to the development of impaired glucose tolerance by comparison with HOMA-ß and the oral disposition index (DI(O)). Overall, 452 subjects were included. PC1/3 activity tended to decrease in type 2 diabetes compared with normal glucose tolerance. PC2 activity showed no difference among the three groups. Decreased estimated PC1/3 activity was significantly associated with type 2 diabetes after adjustment for sex, age, creatinine, triglycerides, HOMA-ß and DI(O). Odds ratios (95% CI) of PC1/3, HOMA-ß, and DI(O) were 2.16 (1.12-4.19), 3.44 (1.82-6.52) and 14.60 (7.87-27.11), respectively. Furthermore, decreased PC1/3(≤1.7) combined with decreased HOMA-ß (≤30) had a sensitivity of 73% and specificity of 62%. Decreased PC1/3 activity may be a useful measurement of beta-cell function alongside decreased HOMA-ß or DI(O). A combined decrease in estimated fasting PC1/3 activity and HOMA-ß measurement led to suspicion of type 2 diabetes in the non-obese Japanese population studied.

Ruptured hepatic metastases of cutaneous melanoma during treatment with vemurafenib: an autopsy case report.

BACKGROUND: The spontaneous rupture of hepatic metastases is rare compared to that of primary hepatic tumors. In addition, vemurafenib, a selective inhibitor of the mutant BRAF protein or gene product, has been reported to be extremely effective in patients with metastatic melanoma who harbor a BRAF V600E mutation. CASE PRESENTATION: A 44-year-old female had previously undergone surgery for resection of a malignant melanoma in the lower right leg. Four years later, hepatic metastases became apparent, and transcatheter arterial embolization (TAE) was performed. Then she underwent treatment with vemurafenib. The size of the hepatic metastases markedly decreased. Two months later, they enlarged rapidly and ruptured, requiring emergency TAE. However, the patient developed hemorrhagic shock and died of renewed intra-abdominal bleeding on the 26th postoperative day. CONCLUSIONS: This is a rare case of ruptured hepatic metastases of malignant melanoma during treatment with vemurafenib. Postmortem examination and immunohistochemical analysis indicated reactivation of the mitogen-activated protein kinase pathway in the metastatic tumor, suggesting secondary resistance to vemurafenib as the possible underlying mechanism.

The glucagon-like peptide 1 receptor agonist enhances intrinsic peroxisome proliferator-activated receptor γ activity in endothelial cells.

Recent studies have suggested glucagon-like peptide-1 (GLP-1) signaling to exert anti-inflammatory effects on endothelial cells, although the precise underlying mechanism remains to be elucidated. In the present study, we investigated whether PPARγ activation is involved in the GLP-1-mediated anti-inflammatory action on endothelial cells. When we treated HUVEC cells with 0.2ng/ml exendin-4, a GLP-1 receptor agonist, endogenous PPARγ transcriptional activity was significantly elevated, by approximately 20%, as compared with control cells. The maximum PPARγ activity enhancing effect of exendin-4 was observed 12h after the initiation of incubation with exendin-4. As H89, a PKA inhibitor, abolished GLP-1-induced PPARγ enhancement, the signaling downstream from GLP-1 cross-talk must have been involved in PPARγ activation. In conclusion, our results suggest that GLP-1 has the potential to induce PPARγ activity, partially explaining the anti-inflammatory effects of GLP-1 on endothelial cells. Cross-talk between GLP-1 signaling and PPARγ activation would have major impacts on treatments for patients at high risk for cardiovascular disease.

Possible involvement of PI3K-dependent pathways in the increased VEGF120 release from osteoblastic cells preloaded with palmitate in vitro.

It have been reported that abnormal bone metabolism often occurs in patients with type 2 diabetes, but the underlying mechanisms remain to be elucidated. In recent years dyslipidemia (hyperlipidemia) has been presumed to have an influence on bone metabolism. In addition, the involvements of VEGF and MCP-1 derived from osteoblasts in bone abnormal metabolism were also observed. Thus, we investigated the pathogenic mechanism of this abnormal bone metabolism, which is included in the regulation of VEGF and MCP-1 secretions from osteoblasts, by using UMR-106 osteosarcoma cells as an osteoblast cell model and treating them with palmitate in order to mimic a state of hyperlipidemia. Palmitate-preloaded cells showed the significant increase of VEGF120 release (1.8-fold vs. control cells, p<0.01). Moreover, the treatment with palmitate significantly increased VEGF-A mRNA with the maximal 2.5-fold upregulation at 12h after the treatment (p<0.01). However, MCP-1 release was not affected by palmitate. Moreover, the amplified VEGF120 secretion with palmitate was significantly decreased by the treatment with TLR4 antagonist or PI3K pathway inhibitors, LY294002 and wortmannin (p<0.01, respectively). On the other hand, the stimulation with TNF-α, which osteoclasts were able to release, significantly enhanced MCP-1 secretion (p<0.01), but had no effect on VEGF120. On the contrary IL-1ß amplified VEGF120 release (p<0.01), but not MCP-1. These results suggest that palmitate can increase VEGF120 release from UMR-106 osteosarcoma cells, which is accelerated at the transcriptional level, and this increase of VEGF120 release may be mediated though, at least partly, TLR4 and the PI3K pathways. In addition, we also verified that TNF-α and IL-1ß, which are considered to be derived from osteoclasts, amplified the secretions of MCP-1 and VEGF120 from UMR-106 cells, respectively.

Estimated proinsulin processing activity of prohormone convertase (PC) 1/3 rather than PC2 is decreased in pancreatic ß-cells of type 2 diabetic patients.

Type 2 diabetic (T2D) patients exhibit fasting relative hyperproinsulinemia owing to pancreatic ß-cell dysfunction. To clarify the mechanism underlying this hyperproinsulinemic state, we evaluated the activities of the endopeptidases prohormone convertase (PC) 1/3 and PC2 in T2D patients. Fasting blood levels of intact proinsulin (IPI), total proinsulin (t-PI) and C-peptide were measured simultaneously, and intravenous glucagon loading was performed to investigate the dynamics of circulating proinsulin-related molecules released from pancreatic ß-cells in 12 healthy volunteers and 18 T2D patients. Taking advantage of the 95% cross-reactivity between proinsulin and des-31,32-proinsulin (des-31,32-PI) with the human proinsulin radioimmunoassay kit used in this study, we estimated PC1/3 and PC2 activities using the following formulas: des-31,32-PI = (t-PI-IPI)/0.95; PC1/3 activity = des-31,32-PI/IPI; and PC2 activity = C-peptide/des-31,32-PI. C-peptide responses to glucagon were slightly lower among T2D patients. IPI and the IPI/C-peptide ratio were significantly higher in T2D patients (p<0.05 and p<0.01, respectively). There was no difference in des-31,32-PI levels or PC2 activity between the two groups. However, PC1/3 activity was significantly lower in T2D patients than in the control group (p<0.01). We propose that decreased activity of PC1/3 rather than PC2 in pancreatic ß-cells is involved in the impaired proinsulin processing, resulting in elevated IPI levels in T2D patients.

[A case of superficial esophageal basaloid squamous cell carcinoma resected by endoscopic submucosal dissection].

A woman in her 70s visited our hospital to undergo endoscopy. Esophagogastroduodenoscopy showed a white submucosal tumor-like lesion in the upper esophagus. Analysis of a biopsy specimen revealed that the tumor was a basaloid squamous cell carcinoma. A superficial squamous cell carcinoma was also revealed near the basaloid squamous cell carcinoma before endoscopic submucosal dissection. Curative en bloc resection was successfully performed. Histopathological examination revealed that the basaloid and superficial squamous cell carcinomas had invaded the lamina propria (pT1a-LPM) and epithelium (pT1a-EP), respectively. In addition, the basaloid squamous cell carcinoma had two different components in terms of malignancy and differentiation. Here we report a rare case of esophageal basaloid squamous cell carcinoma resected by endoscopic submucosal dissection.

[Case of acute necrotizing esophagitis associated with AA amyloidosis secondary to bronchiectasis].

An 82-year-old woman with a history of bronchiectasis for 20 years was admitted to our hospital with anorexia and diarrhea. Sigmoidoscopy showed multiple mucosal erythematous areas and erosions. Histologic examination with Congo red stain revealed massive amyloid deposition around the submucosal vessels as well as in the parenchyma of the mucosa and submucosa. With immunohistochemistry, the diagnosis of secondary/reactive AA amyloidosis was confirmed. Esophagogastroduodenoscopy demonstrated diffuse dark brown mucosa, establishing the diagnosis of acute necrotizing esophagitis. Ischemia associated with amyloid deposition of the vessels in the esophagus was considered to be a possible etiology of acute necrotizing esophagitis. Additionally, gastric outlet obstruction and gastroesophageal reflux associated with gastroduodenal erosions caused by amyloid deposition were supposed to be another factor. Amyloid deposition in the esophageal mucosa may cause a reduction in mucosal defense that is responsible for the pathogenesis. We report the first case of acute necrotizing esophagitis associated with amyloidosis.