Preoperative hemoglobin A1c is associated with postoperative bleeding after vitrectomy for vitreous hemorrhage in patients with diabetic retinopathy.

We previously reported that a high HbA1c level 3 months before vitrectomy for vitreous hemorrhage or a large preoperative decrease in the HbA1c level over 3 months tended to increase the risk of rebleeding in diabetic retinopathy patients evaluated between 2010 and 2014. Here, we aimed to confirm these results with an extended study period and an increased number of operated eyes. This study included 121 diabetic patients who were admitted to Osaka University Hospital between 2010 and 2019 and who underwent vitrectomy for vitreous hemorrhage. Binomial logistic regression analysis was performed with the presence of postoperative bleeding as the outcome. The present study showed that the duration of the operation was associated with rebleeding (odds ratio = 1.02, p = 0.0016). A high HbA1c level just before vitrectomy tended to be associated with the bleeding (odds ratio = 1.27, p = 0.05), while preoperative HbA1c changes were not associated with rebleeding. The results of this study suggest that a high preoperative HbA1c level just before vitrectomy, not a decrease in HbA1c levels, in addition to the duration of the operation may increase the risk of postoperative bleeding after vitrectomy in diabetic retinopathy patients.

Effects of maternal and fetal choline concentrations on the fetal growth and placental DNA methylation of 12 target genes related to fetal growth, adipogenesis, and energy metabolism.

AIM: We performed a birth cohort study involving 124 mother-infant pairs to investigate whether placental DNA methylation is associated with maternal choline status and fetal development. METHODS: Plasma choline concentration was assayed longitudinally in the 1st and 3rd trimesters and at term-pregnancy in mothers and cord blood. Placental DNA methylation was measured for 12 target candidate genes that are related to fetal growth, adipogenesis, lipid and energy metabolism, or long interspersed nuclear elements. RESULTS: Higher maternal plasma and cord blood choline levels at term tended to associate with lower birthweight (r = -0.246, P < 0.013; r = -0.290, P < 0.002) and body mass index (BMI) at birth (r = 0.344, P < 1E-3; r = -0.360, P < 1E-3). The correlation between maternal plasma choline level and cord blood choline level was relatively modest (r = 0.049, P = 0.639). There was an inverse correlation between placental DNA methylation at the retinoid X receptor alpha (RXRA) gene and maternal plasma choline level (r = -0.188 to r = -0.452, P = 0.043 to P < 1E-3 at three points). RXRA methylation level was positively associated with birthweight and BMI at birth (r = 0.306, P = 0.001; r = 0.390, P < 1E-3). Further, RXRA methylation was inversely correlated with RXRA gene expression level (r = 0.333, P < 1E-3). CONCLUSION: Our results suggest that the association between maternal choline status and placental RXRA methylation represents a potential fetal programing mechanism contributing to fetal growth.

Genome-wide profiling of histone H3K27 acetylation featured fatty acid signalling in pancreatic beta cells in diet-induced obesity in mice.

AIMS/HYPOTHESIS: Epigenetic regulation of gene expression has been implicated in the pathogenesis of obesity and type 2 diabetes. However, detailed information, such as key transcription factors in pancreatic beta cells that mediate environmental effects, is not yet available. METHODS: To analyse genome-wide cis-regulatory profiles and transcriptome of pancreatic islets derived from a diet-induced obesity (DIO) mouse model, we conducted chromatin immunoprecipitation coupled with high-throughput sequencing (ChIP-Seq) of histone H3 lysine 27 acetylation (histone H3K27ac) and high-throughput RNA sequencing. Transcription factor-binding motifs enriched in differential H3K27ac regions were examined by de novo motif analysis. For the predicted transcription factors, loss of function experiments were performed by transfecting specific siRNA in INS-1, a rat beta cell line, with and without palmitate treatment. Epigenomic and transcriptional changes of possible target genes were evaluated by ChIP and quantitative RT-PCR. RESULTS: After long-term feeding with a high-fat diet, C57BL/6J mice were obese and mildly glucose intolerant. Among 39,350 islet cis-regulatory regions, 13,369 and 4610 elements showed increase and decrease in ChIP-Seq signals, respectively, significantly associated with global change in gene expression. Remarkably, increased H3K27ac showed a distinctive genomic localisation, mainly in the proximal-promoter regions, revealing enriched elements for nuclear respiratory factor 1 (NRF1), GA repeat binding protein α (GABPA) and myocyte enhancer factor 2A (MEF2A) by de novo motif analysis, whereas decreased H3K27ac was enriched for v-maf musculoaponeurotic fibrosarcoma oncogene family protein K (MAFK), a known negative regulator of beta cells. By siRNA-mediated knockdown of NRF1, GABPA or MEF2A we found that INS-1 cells exhibited downregulation of fatty acid ß-oxidation genes in parallel with decrease in the associated H3K27ac. Furthermore, in line with the epigenome in DIO mice, palmitate treatment caused increase in H3K27ac and induction of ß-oxidation genes; these responses were blunted when NRF1, GABPA or MEF2A were suppressed. CONCLUSIONS/INTERPRETATION: These results suggest novel roles for DNA-binding proteins and fatty acid signalling in obesity-induced epigenomic regulation of beta cell function. DATA AVAILABILITY: The next-generation sequencing data in the present study were deposited at ArrayExpress. RNA-Seq: Dataset name: ERR2538129 (Control), ERR2538130 (Diet-induced obesity) Repository name and number: E-MTAB-6718 - RNA-Seq of pancreatic islets derived from mice fed a long-term high-fat diet against chow-fed controls. ChIP-Seq: Dataset name: ERR2538131 (Control), ERR2538132 (Diet-induced obesity) Repository name and number: E-MTAB-6719 - H3K27ac ChIP-Seq of pancreatic islets derived from mice fed a long-term high-fat diet (HFD) against chow-fed controls.

Genome-wide DNA methylation analysis during non-alcoholic steatohepatitis-related multistage hepatocarcinogenesis: comparison with hepatitis virus-related carcinogenesis.

The aim of this study was to clarify the significance of DNA methylation alterations during non-alcoholic steatohepatitis (NASH)-related hepatocarcinogenesis. Single-CpG-resolution genome-wide DNA methylation analysis was performed on 264 liver tissue samples using the Illumina Infinium HumanMethylation450 BeadChip. After Bonferroni correction, 3331 probes showed significant DNA methylation alterations in 113 samples of non-cancerous liver tissue showing NASH (NASH-N) as compared with 55 samples of normal liver tissue (NLT). Principal component analysis using the 3331 probes revealed distinct DNA methylation profiles of NASH-N samples that were different from those of NLT samples and 37 samples of non-cancerous liver tissue showing chronic hepatitis or cirrhosis associated with hepatitis B virus (HBV) or hepatitis C virus (HCV) infection (viral-N). Receiver operating characteristic curve analysis identified 194 probes that were able to discriminate NASH-N samples from viral-N samples with area under the curve values of more than 0.95. Jonckheere-Terptsra trend test revealed that DNA methylation alterations in NASH-N samples from patients without hepatocellular carcinoma (HCC) were inherited by or strengthened in NASH-N samples from patients with HCC, and then inherited by or further strengthened in 22 samples of NASH-related HCC (NASH-T) themselves. NASH- and NASH-related HCC-specific DNA methylation alterations, which were not evident in viral-N samples and 37 samples of HCC associated with HBV or HCV infection, were observed in tumor-related genes, such as WHSC1, and were frequently associated with mRNA expression abnormalities. These data suggested that NASH-specific DNA methylation alterations may participate in NASH-related multistage hepatocarcinogenesis.

Comprehensive exploration of novel chimeric transcripts in clear cell renal cell carcinomas using whole transcriptome analysis.

The aim of this study was to clarify the participation of expression of chimeric transcripts in renal carcinogenesis. Whole transcriptome analysis (RNA sequencing) and exploration of candidate chimeric transcripts using the deFuse program were performed on 68 specimens of cancerous tissue (T) and 11 specimens of non-cancerous renal cortex tissue (N) obtained from 68 patients with clear cell renal cell carcinomas (RCCs) in an initial cohort. As positive controls, two RCCs associated with Xp11.2 translocation were analyzed. After verification by reverse transcription (RT)-PCR and Sanger sequencing, 26 novel chimeric transcripts were identified in 17 (25%) of the 68 clear cell RCCs. Genomic breakpoints were determined in five of the chimeric transcripts. Quantitative RT-PCR analysis revealed that the mRNA expression levels for the MMACHC, PTER, EPC2, ATXN7, FHIT, KIFAP3, CPEB1, MINPP1, TEX264, FAM107A, UPF3A, CDC16, MCCC1, CPSF3, and ASAP2 genes, being partner genes involved in the chimeric transcripts in the initial cohort, were significantly reduced in 26 T samples relative to the corresponding 26 N samples in the second cohort. Moreover, the mRNA expression levels for the above partner genes in T samples were significantly correlated with tumor aggressiveness and poorer patient outcome, indicating that reduced expression of these genes may participate in malignant progression of RCCs. As is the case when their levels of expression are reduced, these partner genes also may not fully function when involved in chimeric transcripts. These data suggest that generation of chimeric transcripts may participate in renal carcinogenesis by inducing dysfunction of tumor-related genes.

Decreased islet amyloid polypeptide staining in the islets of insulinoma patients.

Islet amyloid polypeptide (IAPP) is a factor that regulates food intake and is secreted from both pancreatic islets and insulinoma cells. Here, we aimed to evaluate IAPP immunohistochemically in islets or insulinoma cells in association with clinical characteristics. We recruited six insulinoma patients and six body mass index-matched control patients with pancreatic diseases other than insulinoma whose glucose tolerance was confirmed to be normal preoperatively. IAPP and IAPP-insulin double staining were performed on pancreatic surgical specimens. We observed that the IAPP staining level and percentage of IAPP-positive beta cells tended to be lower (p = 0.1699) in the islets of insulinoma patients than in those of control patients, which might represent a novel IAPP expression pattern under persistent hyperinsulinemia and hypoglycemia.

Single-housing-induced islet epigenomic changes are related to polymorphisms in diabetic KK mice.

A lack of social relationships is increasingly recognized as a type 2 diabetes (T2D) risk. To investigate the underlying mechanism, we used male KK mice, an inbred strain with spontaneous diabetes. Given the association between living alone and T2D risk in humans, we divided the non-diabetic mice into singly housed (KK-SH) and group-housed control mice. Around the onset of diabetes in KK-SH mice, we compared H3K27ac ChIP-Seq with RNA-Seq using pancreatic islets derived from each experimental group, revealing a positive correlation between single-housing-induced changes in H3K27ac and gene expression levels. In particular, single-housing-induced H3K27ac decreases revealed a significant association with islet cell functions and GWAS loci for T2D and related diseases, with significant enrichment of binding motifs for transcription factors representative of human diabetes. Although these H3K27ac regions were preferentially localized to a polymorphic genomic background, SNVs and indels did not cause sequence disruption of enriched transcription factor motifs in most of these elements. These results suggest alternative roles of genetic variants in environment-dependent epigenomic changes and provide insights into the complex mode of disease inheritance.

Glucocorticoid receptor-NECAB1 axis can negatively regulate insulin secretion in pancreatic ß-cells.

The mechanisms of impaired glucose-induced insulin secretion from the pancreatic ß-cells in obesity have not yet been completely elucidated. Here, we aimed to assess the effects of adipocyte-derived factors on the functioning of pancreatic ß-cells. We prepared a conditioned medium using 3T3-L1 cell culture supernatant collected at day eight (D8CM) and then exposed the rat pancreatic ß-cell line, INS-1D. We found that D8CM suppressed insulin secretion in INS-1D cells due to reduced intracellular calcium levels. This was mediated by the induction of a negative regulator of insulin secretion-NECAB1. LC-MS/MS analysis results revealed that D8CM possessed steroid hormones (cortisol, corticosterone, and cortisone). INS-1D cell exposure to cortisol or corticosterone increased Necab1 mRNA expression and significantly reduced insulin secretion. The increased expression of Necab1 and reduced insulin secretion effects from exposure to these hormones were completely abolished by inhibition of the glucocorticoid receptor (GR). NECAB1 expression was also increased in the pancreatic islets of db/db mice. We demonstrated that the upregulation of NECAB1 was dependent on GR activation, and that binding of the GR to the upstream regions of Necab1 was essential for this effect. NECAB1 may play a novel role in the adipoinsular axis and could be potentially involved in the pathophysiology of obesity-related diabetes mellitus.

Relationships between intra-pancreatic fat deposition and lifestyle factors: a cross-sectional study.

Aims: The excess deposition of intra-pancreatic fat deposition (IPFD) has been reported to be associated with type 2 diabetes, chronic pancreatitis, and pancreatic ductal adenocarcinoma. In the current study, we aimed to identify a relationship between lifestyle factors and IPFD. Materials and methods: 99 patients admitted to the Osaka University Hospital who had undergone abdominal computed tomography were selected. We evaluated the mean computed tomography values of the pancreas and spleen and then calculated IPFD score. Multiple regression analyses were used to assess the associations between IPFD score and lifestyle factors. Results: Fast eating speed, late-night eating, and early morning awakening were significantly associated with a high IPFD score after adjusting for age, sex, diabetes status and Body Mass Index (p=0.04, 0.01, 0.01, respectively). Conclusion: The current study has elucidated the significant associations of fast eating speed, late-night eating, and early morning awakening with IPFD.

Lipid droplet accumulation in ß cells in patients with type 2 diabetes is associated with insulin resistance, hyperglycemia and ß cell dysfunction involving decreased insulin granules.

Background and objective: Pancreatic fat is a form of ectopic fat. Lipid droplets (LDs) are also observed in ß cells; however, the pathophysiological significance, especially for ß cell function, has not been elucidated. Our aim was to assess LD accumulation in ß cells in various stages of glucose intolerance and to clarify its relationship with clinical and histological parameters. Methods: We examined 42 Japanese patients who underwent pancreatectomy. The BODIPY493/503-positive (BODIPY-positive) area in ß cells was measured in pancreatic sections from 32 patients. The insulin granule numbers were counted in an additional 10 patients using electron microscopy. Results: The BODIPY-positive area in ß cells in preexisting type 2 diabetes patients was higher than that in normal glucose tolerance patients (p = 0.031). The BODIPY-positive area in ß cells was positively correlated with age (r = 0.45, p = 0.0097), HbA1c (r = 0.38, p = 0.0302), fasting plasma glucose (r = 0.37, p = 0.045), and homeostasis model assessment insulin resistance (r = 0.41, p = 0.049) and negatively correlated with an increase in the C-peptide immunoreactivity level by the glucagon test (r = -0.59, p = 0.018). The ratio of mature insulin granule number to total insulin granule number was reduced in the patients with rich LD accumulation in ß cells (p = 0.039). Conclusions: Type 2 diabetes patients had high LD accumulation in ß cells, which was associated with insulin resistance, hyperglycemia, aging and ß cell dysfunction involving decreased mature insulin granules.

Consumption of two meals per day is associated with increased intrapancreatic fat deposition in patients with type 2 diabetes: a retrospective study.

INTRODUCTION: This study aimed to identify the associations between lifestyle factors and intrapancreatic fat deposition in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: The participants were 185 patients with type 2 diabetes who were hospitalized at Osaka University Hospital between 2008 and 2020 and underwent abdominal CT during hospitalization. Information regarding lifestyle factors, including the number of meals consumed per day, snacking habits, exercise habits, exercise at work, smoking habits, alcohol intake, insomnia, sleep apnea syndrome, and night-shift working, was acquired from self-administered questionnaires or medical records. We measured the mean CT values for the pancreas (P), liver (L), and spleen (S), and the visceral fat area (VFA), and quantified intrapancreatic and liver ectopic fat accumulation as P-S and L-S, respectively. RESULTS: After adjustment for age, sex, hemoglobin A1c, and body mass index (BMI), participants who consumed two meals per day had significantly lower P-S (higher intrapancreatic fat deposition, p=0.02) than those who consumed three meals per day. There were no significant associations between the number of meals consumed and liver ectopic fat accumulation and VFA (p=0.73 and p=0.67, respectively). CONCLUSIONS: Patients with diabetes who consumed two meals per day showed greater intrapancreatic fat deposition than those who consumed three meals per day, even after adjustment for BMI. These findings support the current guideline for diabetes treatment that skipping meals should be avoided.

Quantification of DNA methylation for carcinogenic risk estimation in patients with non-alcoholic steatohepatitis.

BACKGROUND: In recent years, non-alcoholic steatohepatitis (NASH) has become the main cause of hepatocellular carcinoma (HCC). As a means of improving the treatment of NASH-related HCCs based on early detection, this study investigated the feasibility of carcinogenic risk estimation in patients with NASH. RESULTS: Normal liver tissue (NLT), non-cancerous liver tissue showing histological findings compatible with non-alcoholic fatty liver from patients without HCC (NAFL-O), non-cancerous liver tissue showing NASH from patients without HCC (NASH-O), non-cancerous liver tissue showing non-alcoholic fatty liver from patients with HCC (NAFL-W), non-cancerous liver tissue showing NASH from patients with HCC (NASH-W) and NASH-related HCC were analyzed. An initial cohort of 171 tissue samples and a validation cohort of 55 tissue samples were used. Genome-wide DNA methylation screening using the Infinium HumanMethylation450 BeadChip and DNA methylation quantification using high-performance liquid chromatography (HPLC) with a newly developed anion-exchange column were performed. Based on the Infinium assay, 4050 CpG sites showed alterations of DNA methylation in NASH-W samples relative to NLT samples. Such alterations at the precancerous NASH stage were inherited by or strengthened in HCC samples. Receiver operating characteristic curve analysis identified 415 CpG sites discriminating NASH-W from NLT samples with area under the curve values of more than 0.95. Among them, we focused on 21 CpG sites showing more than 85% specificity, even for discrimination of NASH-W from NASH-O samples. The DNA methylation status of these 21 CpG sites was able to predict the coincidence of HCC independently from histopathological findings such as ballooning and fibrosis stage. The methylation status of 5 candidate marker CpG sites was assessed using a HPLC-based system, and for 3 of them sufficient sensitivity and specificity were successfully validated in the validation cohort. By combining these 3 CpG sites including the ZC3H3 gene, NAFL-W and NASH-W samples from which HCCs had already arisen were confirmed to show carcinogenic risk with 95% sensitivity in the validation cohort. CONCLUSIONS: After a further prospective validation study using a larger cohort, carcinogenic risk estimation in liver biopsy specimens of patients with NASH may become clinically applicable using this HPLC-based system for quantification of DNA methylation.

The HNF-1 target collectrin controls insulin exocytosis by SNARE complex formation.

Defective glucose-stimulated insulin secretion is the main cause of hyperglycemia in type 2 diabetes mellitus. Mutations in HNF-1alpha cause a monogenic form of type 2 diabetes, maturity-onset diabetes of the young (MODY), characterized by impaired insulin secretion. Here we report that collectrin, a recently cloned kidney-specific gene of unknown function, is a target of HNF-1alpha in pancreatic beta cells. Expression of collectrin was decreased in the islets of HNF-1alpha (-/-) mice, but was increased in obese hyperglycemic mice. Overexpression of collectrin in rat insulinoma INS-1 cells or in the beta cells of transgenic mice enhanced glucose-stimulated insulin exocytosis, without affecting Ca(2+) influx. Conversely, suppression of collectrin attenuated insulin secretion. Collectrin bound to SNARE complexes by interacting with snapin, a SNAP-25 binding protein, and facilitated SNARE complex formation. Therefore, collectrin is a regulator of SNARE complex function, which thereby controls insulin exocytosis.

Characterization of the taste receptor-related G-protein, α-gustducin, in pancreatic ß-cells.

AIMS/INTRODUCTION: Taste receptors, T1rs and T2rs, and the taste-selective G-protein, α-gustducin, are expressed outside the taste-sensing system, such as enteroendocrine L cells. Here, we examined whether α-gustducin also affects nutrition sensing and insulin secretion by pancreatic ß-cells. MATERIALS AND METHODS: The expression of α-gustducin and taste receptors was evaluated in ß-cell lines, and in rat and mouse islets either by quantitative polymerase chain reaction or fluorescence immunostaining. The effects of α-gustducin knockdown on insulin secretion and on cyclic adenosine monophosphate and intracellular Ca2+ levels in rat INS-1 cells were estimated. Sucralose (taste receptor agonist)-induced insulin secretion was investigated in INS-1 cells with α-gustducin suppression and in islets from mouse disease models. RESULTS: The expression of Tas1r3 and α-gustducin was confirmed in ß-cell lines and pancreatic islets. Basal levels of cyclic adenosine monophosphate, intracellular calcium and insulin secretion were significantly enhanced with α-gustducin knockdown in INS-1 cells. The expression of α-gustducin was decreased in high-fat diet-fed mice and in diabetic db/db mice. Sucralose-induced insulin secretion was not attenuated in INS-1 cells with α-gustducin knockdown or in mouse islets with decreased expression of α-gustducin. CONCLUSIONS: α-Gustducin is involved in the regulation of cyclic adenosine monophosphate, intracellular calcium levels and insulin secretion in pancreatic ß-cells in a manner independent of taste receptor signaling. α-Gustducin might play a novel role in ß-cell physiology and the development of type 2 diabetes.

Expression of HNF-4alpha (MODY1), HNF-1beta (MODY5), and HNF-1alpha (MODY3) proteins in the developing mouse pancreas.

The type 1, 3, and 5 forms of maturity-onset diabetes of the young (MODY) are caused by mutations of the genes encoding hepatocyte nuclear factor (HNF)-4alpha, HNF-1alpha, and HNF-1beta, respectively [Yamagata, K., Oda, N., Kaisaki, P.J., Menzel, S., Furuta, H., Vaxillaire, M., et al., 1996a. Mutations in the hepatocyte nuclear factor-1alpha gene in maturity-onset diabetes of the young (MODY3). Nature 384, 455-458; Yamagata, K., Furuta, H., Oda, N., Kaisaki, P.J., Menzel, S., Cox, N.J., et al., 1996b. Mutations in the hepatocyte nuclear factor-4alpha gene in maturity-onset diabetes of the young (MODY1). Nature 384, 458-460; Horikawa, Y., Iwasaki, N., Hara, M., Furuta, H., Hinokio, Y., Cockburn, B.N. et al., 1997. Mutation in hepatocyte nuclear factor-1beta gene (TCF2) associated with MODY. Nat. Genet. 17, 384-385]. Among these transcription factors, the pattern of HNF-4alpha expression during pancreatic differentiation remains largely unknown. We performed an immunohistochemical study to investigate its expression in comparison with the expression of HNF-1alpha and HNF-1beta. We found considerable variation in the level of HNF-4alpha expression by the individual epithelial cells in the pancreatic buds on E9.5. HNF-4alpha and HNF-1beta were initially expressed by Pdx1(+) common progenitor cells and neurogenin3(+) (Ngn3(+)) endocrine precursor cells during the first transition, but expression of HNF-1beta and either HNF-4alpha or HNF-1alpha became complementary around the end of the second transition (E15.5). In the mature pancreas, HNF-4alpha was expressed by glucagon-positive alpha-cells, insulin-positive beta-cells, somatostatin-positive delta-cells, and pancreatic polypeptide-positive PP-cells, as well as by pancreatic exocrine cells and ductal cells. Most of the HNF-4alpha(+) cells were also positive for HNF-1alpha, but HNF-4alpha expression in some non-beta-cells was remarkably high, and this was not paralleled by high HNF-1alpha expression. These results indicate that the expression of MODY proteins in each of the pancreatic cell types is strictly regulated in accordance with the status of differentiation during pancreatic organogenesis.

A type 2 diabetes-associated SNP in KCNQ1 (rs163184) modulates the binding activity of the locus for Sp3 and Lsd1/Kdm1a, potentially affecting CDKN1C expression.

Although genome-wide association studies have shown that potassium voltage-gated channel subfamily Q member 1 (KCNQ1) is one of the genes that is most significantly associated with type 2 diabetes mellitus (T2DM), functionally annotating disease-associated single nucleotide polymorphisms (SNPs) remains a challenge. Recently, our group described a novel strategy to identify proteins that bind to SNP-containing loci in an allele-specific manner. The present study successfully applied this strategy to investigate rs163184, a T2DM susceptibility SNP located in the intronic region of KCNQ1. Comparative analysis of DNA-binding proteins revealed that the binding activities for the genomic region containing SNP rs163184 differed between alleles for several proteins, including Sp3 and Lsd1/Kdm1a. Sp3 preferentially bound to the non-risk rs163184 allele and stimulated transcriptional activity in an artificial promoter containing this region. Lsd1/Kdm1a was identified to be preferentially recruited to the non-risk allele of the rs163184 region and reduced Sp3-dependent transcriptional activity in the artificial promoter. In addition, expression of the nearby cyclin­dependent kinase inhibitor 1C (CDKN1C) gene was revealed to be upregulated after SP3 knockdown in cells that possessed non-risk alleles. This suggests that CDKN1C is potentially one of the functional targets of SNP rs163184, which modulates the binding activity of the locus for Sp3 and Lsd1/Kdm1a.

Development of complementary expression patterns of E- and N-cadherin in the mouse liver.

AIM: Cadherins, Ca(2+)-dependent cell adhesion molecules, are known to play essential roles in morphogenesis and organogenesis. However, the role of cadherins in liver organogenesis remains poorly understood. The aim of this study is to clarify the expression patterns and levels of these cadherins in the developing and maturing mouse liver. METHODS: The expression of E- and N-cadherin was investigated immunohistochemically and levels were determined by immunoblots. RESULTS: In the hepatic primordia E-cadherin, but not N- cadherin, was weakly expressed. As development proceeded, N-cadherin became coexpressed with E-cadherin in a single hepatocyte. The expression was uniform throughout the liver and the amount of these cadherins gradually increased. In the first postnatal week during the initial formation of the architecture of the liver lobule, the distribution of these cadherins gradually changed to the complementary pattern of the adult type, i.e. E-cadherin was expressed in the periportal zones, while N-cadherin was expressed in the perivenous zones. CONCLUSION: The complementary expression patterns of E- and N-cadherin between the periportal and perivenous zones developed gradually after birth. This specific regional localization of each cadherin may serve as an aid in defining different functional regions in the mouse liver lobule.

Hepatocyte nuclear factor-1alpha modulates pancreatic beta-cell growth by regulating the expression of insulin-like growth factor-1 in INS-1 cells.

Maturity-onset diabetes of the young type 3 (MODY3) is characterized by impaired insulin secretion. Heterozygous mutations in the gene encoding hepatocyte nuclear factor (HNF)-1alpha are the cause of MODY3. Transgenic mice overexpressing dominant-negative HNF-1alpha mutant in pancreatic beta-cells and HNF-1alpha knockout mice are animal models of MODY3. These mice exhibit defective glucose-stimulated insulin secretion and have reduced beta-cell mass and beta-cell proliferation rate. Here we examined the effect of HNF-1alpha on beta-cell proliferation by overexpressing a human naturally occurring dominant- negative mutation P291fsinsC in INS-1 cells under the control of doxycycline-induction system. INS-1 cells overexpressing P291fsinsC showed apparent growth impairment. The proliferation rate estimated by [(3)H]thymidine incorporation was significantly reduced in P291fsinsC-expressing INS-1 cells compared with noninduced or wild-type HNF-1alpha-overexpressing INS-1 cells. Growth inhibition occurred at the transition from G1 to S cell cycle phase, with reduced expression of cyclin E and upregulation of p27. cDNA array analysis revealed that the expression levels of IGF-1, a major growth factor for beta-cells, and macrophage migration inhibitory factor (MIF), a cytokine expressed in pancreatic beta-cells, were reduced in P291fsinsC-HNF-1alpha-expressing INS-1 cells. Although MIF seemed to have proliferative function, blockade of MIF action by anti-MIF antibody stimulated INS-1 cell proliferation, excluding its direct role in the growth impairment. However, addition of IGF-1 to P291fsinsC-expressing INS-1 cells rescued the growth inhibition. Our data suggest that HNF-1alpha is critical for modulating pancreatic beta-cell growth by regulating IGF-1 expression. IGF-1 might be a potential therapeutic target for the treatment of MODY3.

Overexpression of PACAP in transgenic mouse pancreatic beta-cells enhances insulin secretion and ameliorates streptozotocin-induced diabetes.

Pituitary adenylate cyclase-activating polypeptide (PACAP), a member of the vasoactive intestinal peptide/secretin/glucagon family, stimulates insulin secretion from islets in a glucose-dependent manner at femtomolar concentrations. To assess PACAP's pancreatic function in vivo, we generated transgenic mice overexpressing PACAP in the pancreas under the control of human insulin promoter. Northern blot and immunohistochemical analyses showed that PACAP is overexpressed in pancreatic islets, specifically in transgenic mice. Plasma glucose and glucagon levels during a glucose tolerance test were not different between PACAP transgenic mice and nontransgenic littermates. However, plasma insulin levels in transgenic mice were higher after glucose loading. Also, increases of streptozotocin-induced plasma glucose were attenuated in transgenic compared with nontransgenic mice. Notably, an increase in 5-bromo-2-deoxyuridine-positive beta-cells in the streptozotocin-treated transgenic mice was observed but without differences in the staining patterns by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling. Morphometric analysis revealed that total islet mass tends to increase in 12-month-old transgenic mice but showed no difference between 12-week-old transgenic and nontransgenic littermates. This is the first time that PACAP has been observed to play an important role in the proliferation of beta-cells.