Increased IRS2 mRNA Expression in SGA Neonates: PCR Analysis of Insulin/IGF Signaling in Cord Blood.

CONTEXT: Hypoglycemia is the most common metabolic problem among small-for-gestational-age (SGA) neonates. However, the pathological mechanism and insulin/ insulin-like growth factor (IGF) signaling axis in neonates remain unknown. OBJECTIVE: To determine the insulin/IGF axis in neonates, we analyzed the messenger RNA (mRNA) expression of insulin/IGF signaling in fetal umbilical cord blood. SETTING: The Perinatal Medical Center of Tottori University Hospital. PARTICIPANTS: Fifty-two [42 appropriate-for-gestational-age (AGA) and 10 SGA] neonates. INTERVENTIONS: Immediately collected cord blood was placed into a PAXgene Blood RNA Tube. Total RNA from the blood was purified using reagents provided in the PAXgene Blood RNA Kit within 4 days, and reverse transcription polymerase chain reaction (PCR) was performed. MAIN OUTCOME MEASURE: Quantitative real-time PCR analysis was applied to evaluate the mRNA expression of insulin receptor (INSR), IGF-I receptor (IGF1R), insulin receptor substrate 1 (IRS1), IRS2, and glucose transporters (SLC2A2 and SLC2A4). ß-Actin was used as a control gene. RESULTS: Serum glucose and IGF-I levels in SGA neonates were significantly lower. The cord serum insulin levels were similar between AGA and SGA neonates. The IRS2 mRNA expression was significantly higher in SGA than in AGA neonates (P < 0.05). The IRS2 mRNA expression was significantly higher in hypoglycemic SGA neonates than in normoglycemic SGA neonates. CONCLUSIONS: We determined that intrauterine growth restriction induces increased IRS2 mRNA expression in cord blood, without hyperinsulinemia. The increased expression of IRS2 mRNA might be associated with abnormal glucose metabolism in SGA neonates. Our findings might lead to the elucidation of abnormal glucose metabolism in SGA neonates.

A novel frameshift mutation in NR3C2 leads to decreased expression of mineralocorticoid receptor: a family with renal pseudohypoaldosteronism type 1.

Pseudohypoaldosteronism type 1 (PHA1) is a rare genetic disease characterized by resistance to aldosterone, and the renal form of PHA1 is associated with heterozygous inactivating mutations in NR3C2, which encodes mineralocorticoid receptor (MR). Here we report a case of renal PHA1 due to a novel frameshift mutation in NR3C2. A 10-day-old Japanese male infant, born at 39 weeks gestation (birth weight, 2,946 g), was admitted to our hospital because of lethargy and vomiting, with a 6.7% weight loss since birth. Laboratory test results were: Na+, 132 mEq/L; K+, 6.6 mEq/L; Cl+, 93 mEq/L. Both plasma aldosterone level and plasma renin activity were markedly elevated at diagnosis, 2,940 ng/dL (normal range: 26.9-75.8 ng/dL) and 560 ng/mL/h (normal range 3.66-12.05 ng/mL/h), respectively. Direct sequence analysis of NR3C2 revealed a novel heterozygous mutation (c.3252delC) in the patient and his father. The mutation causes a frameshift starting at amino acid I 963 within the C terminal ligand-binding domain of MR and results in a putative abnormal stop codon at amino acid 994, with an extension of 10 amino acids compared to normal MR. We performed cell culture experiments to determine the levels of mutant NR3C2 mRNA and MR, and evaluate the effects of the mutation on MR response to aldosterone. The mutation decreased the expression of MR, but not NR3C2 mRNA, and led to decreased MR function, with no dominant negative effect. These results provide important information about MR function and NR3C2 mutation in PHA1.

Heterozygous nonsense mutations near the C-terminal region of IGF1R in two patients with small-for-gestational-age-related short stature.

OBJECTIVE: The type I insulin-like growth factor I receptor (IGF1R) plays an important role in growth. We aimed to evaluate the detailed mechanism underlying the effect of IGF1R on human growth. PATIENTS AND METHODS: We have performed sequence analysis of IGF1R in 55 patients with SGA short stature in Japan, since 2004, and identified novel heterozygous nonsense mutations in 2 patients: an 8-year-old Japanese boy (case 1), with a birthweight of 2228 g (-3·3 SDS) and height of 46 cm (-2·1 SDS), and a 3-year-old Japanese girl (case 2), with a birthweight of 2110 g (-3·0 SDS) and height of 44·3 cm (-2·8 SDS). Both patients had a short stature (-3·2 SDS, -3·1 SDS). We determined the protein expression of mutated IGF1R, assessed the effect of the endoplasmic reticulum-associated degradation (ERAD) pathway on mutated IGF1R, assessed the dominant-negative effect of IGF1R and performed quantitative RT-PCR analysis of IGF1R mRNA expression in whole blood cells. RESULTS: Two novel heterozygous nonsense mutations (case 1: p.Q1250X and case 2: p.W1249X) were identified. Although these mutations did not affect blood IGF1R mRNA levels, they significantly decreased the expression of IGF1R protein in transiently transfected cells. Treatment with the proteasome inhibitor MG132 showed significantly increased IGF1R protein. CONCLUSIONS: Heterozygous nonsense mutations affecting the C-terminal region (p.Q1250X, p.W1249X) of IGF1R decreased the expression of IGF1R through the ERAD pathway. Our study revealed the importance of the C-terminal region and the dosage of this receptor for growth.

A rare CYP 21 mutation (p.E431K) induced deactivation of CYP 21A2 and resulted in congenital adrenal hyperplasia.

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency is caused by mutations in the CYP21A2 gene. The residual enzyme activity is strongly associated with the phenotype. We describe a rare case of CAH with a rare CYP21A2 mutation. The patient was a one-year-old Japanese boy. At 16 days old, he was referred to our hospital because of elevated serum 17-OH-progesterone (17-OHP) levels in neonatal screening. The compound heterozygous mutations (IVS2-13 A/C>G, and p.E431K) in CYP21A2 were identified at 2 months old, and we diagnosed non-classical CAH, since he did not have significant physical signs (pigmentation and salt-wasting). However, his body weight decreased, and his serum 17-OHP level (99.5 ng/mL) was elevated at 3 months old. Steroid replacement therapy was started at 3 months old. Our patient's clinical course resembled simple virilizing (SV) CAH, but classification was difficult because the patient showed increased renin activity indicating an aldosterone deficiency, and late onset of symptoms. While the IVS 2-13 A/C>G mutation is common in the classical form of CAH, p.E431K is a rare point mutation. Functional analysis revealed that the residual enzyme activity of p.E431L was 5.08±2.55% for 17-OHP and 4.12±2.37% for progesterone, which is consistent with SV CAH. p.E431 is localized in the L-helix near the heme-binding site. The mutation might interfere with heme binding, leading to deactivation of CYP21A2. This report showed that CYP21A2 p.E431 has an important effect on enzyme activity.

Clinical overview of nephrogenic diabetes insipidus based on a nationwide survey in Japan.

BACKGROUND: Nephrogenic diabetes insipidus (NDI) is a rare disease whose complications include polyuria, renal dysfunction, growth disorder and mental retardation. The details of NDI's clinical course have been unclear. To address this uncertainty, we performed a large investigation of the clinical course of NDI in Japan. METHODS: Between December 2009 and March 2011, we provided a primary questionnaire to 26,282 members of the Japan Endocrine Society, the Japanese Urological Association, the Japanese Society for Pediatric Endocrinology, the Japanese Society for Pediatric Nephrology, the Japanese Society of Nephrology, the Japanese Society of Neurology and the Japanese Society of Pediatric Urology. In addition, we provided a secondary questionnaire to 121 members who reported experience with cases of NDI. We asked about patient's age at onset, diagnosis, complications, effect of treatment and patient's genotype. RESULTS: We enrolled 173 patients with NDI in our study. Of these NDI patients, 143 were congenital and 30 were acquired. Of the 173, 73 patients (42%) experienced urologic complications. Among the 143 with congenital NDI, 20 patients (14%) had mental retardation. Patients with NDI mainly received thiazide diuretics, and some patients responded to treatment with desmopressin acetate (DDAVP). Gene analyses were performed in 87 patients (61%) with congenital NDI, revealing that 65 patients had an arginine vasopressin receptor type 2 (AVPR2) gene mutation and that 8 patients (9.2%) had an aquaporin 2 (AQP2) gene mutation. Patients with the AVPR2 mutation (D85N) generally showed a mild phenotype, and we found that DDAVP was generally an effective treatment for NDI among these patients. CONCLUSION: We suggest that adequate diagnosis and treatment are the most important factors for improving prognoses. We further suggest that gene analysis should be performed for optimal treatment selection and the early detection of NDI among siblings.

Interaction of Muc4 and ErbB2 in a transgenic mouse model of gallbladder carcinoma: potential pathobiological implications.

The molecular mechanism of gallbladder carcinogenesis and cancer growth remains unknown. BK5.erbB2 transgenic mice in which erbB2 is overexpressed and activated in the biliary epithelia develop adenocarcinoma of the gallbladder at a high incidence. Although it has been reported that erbB2 plays an important role in tumorigenesis, little is known about the involvement of its ligand(s). The expression level of Muc4, a potential functional ligand for erbB2, and its interaction with erbB2 in the gallbladder of BK5.erbB2 mice were determined. By immunohistochemistry and in situ hybridization, both Muc4 mRNA and protein levels were strongly expressed in the cancerous epithelia of gallbladder from BK5.erbB2 mice. Also, in the hyperplastic (precancerous) epithelia, the protein levels were modestly expressed. Immunostaining with Muc4 (ASGP2) Ab overlapped with that with erbB2 Ab in the apical membranous components of the cancerous epithelia, indicating the co-localization of Muc4 and erbB2. Immunoprecipitation experiments revealed an interaction between Muc4 and erbB2 in the gallbladders. The interaction was associated with the hyperphosphorylation of erbB2, MAPK and Akt, and also with the overexpression of cyclooxygenase-2. However, in other organs that overexpressed erbB2 (trachea, esophagus and forestomach), Muc4 was expressed in only trace or modest amounts, and erbB2 was not hyperphosphorylated. Collectively, Muc4 is upregulated and interacts with erbB2 in gallbladders from BK5.erbB2 mice. It is likely that Muc4 plays an important role during gallbladder carcinogenesis and/or cancer growth by potentiating erbB2 signaling.

Loss of UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase 3 and reduced O-glycosylation in colon carcinoma cells selected for hepatic metastasis.

O-glycosylation of mucin is initiated by the attachment of N-acetyl-D-galactosamine (GalNAc) to serine or threonine residues in mucin core polypeptides by UDPGalNAc:polypeptide N-acetylgalactosaminyltransferases (ppGalNAc-Ts). It is not well understood how GalNAc attachment is regulated by multiple ppGalNAc-Ts in each cell. In the present study, the expression levels of murine ppGalNAc-Ts (mGalNAc-Ts), T1, T2, T3, T4, T6, and T7 were compared between mouse colon carcinoma colon 38 cells and variant SL4 cells, selected for their metastatic potentials, by using the competitive RT-PCR method. The expression levels of mGalNAc-T1, T2, and T7 were slightly higher in the SL4 cells than in the colon 38 cells, whereas the expression level of mGalNAc-T3 in the SL4 cells was 1.5% of that in the colon 38 cells. Products of enzymatic incorporations of GalNAc residues into FITCPTTTPITTTTK peptide by the use of microsome fractions of these cells as the enzyme source were separated and characterized for the number of attached GalNAc residues and their positions. The maximum number of attached GalNAc residues was 6 and 4 when the microsome fractions of the colon 38 cells and SL4 cells were used, respectively. When the microsome fractions of the colon 38 cells were treated with a polyclonal antibody raised against mGalNAc-T3, the maximum number of incorporated GalNAc residues was 4. These results strongly suggest that mGalNAc-T3 in colon 38 cells is involved in additional transfer of GalNAc residues to this peptide.

MUC4 interacts with ErbB2 in human gallbladder carcinoma: potential pathobiological implications.

Muc4 interacts with erbB2 and potentiates tumourigenesis and/or tumour growth. The expression of MUC4, the interaction of MUC4 with erbB2 and the status of erbB2 signalling in human gallbladder carcinomas were determined in order to gain a better understanding of the pathobiology. The expression levels of MUC4 protein and mRNA were increased in specimens of gallbladder carcinoma. Immunoprecipitation experiments showed an interaction between MUC4 and erbB2. This interaction was associated with the hyperphosphorylation of erbB2, MAPK and Akt and with the overexpression of cyclooxygenase-2. MUC4 was detected on the apical surface of cancerous epithelia and partially co-localised there with erbB2. Transfection experiments showed that MUC4 amplifies cell proliferation in the presence of heregulin through potentiating phosphorylation of erbB2 and its downstream signalling pathways. These findings suggest that MUC4 is up-regulated and interacts with erbB2 in human gallbladder carcinoma, and thereby support the potential implication of MUC4 in erbB2 activation.

Expression of MUC1 recognized by monoclonal antibody MY.1E12 is a useful biomarker for tumor aggressiveness of advanced colon carcinoma.

To address the need for new prognostic parameters in advanced colon carcinoma that could add insights into the aggressiveness of tumors, the expression levels of MUC1 recognized by a monoclonal antibody (mAb) MY.1E12 in archival specimens from 123 Japanese patients with colon carcinomas were evaluated by immunohistochemistry to correlate the results with clinicopathological characteristics. The localization of mAb MY.1E12-reactive-MUC1 (MY.1E12-MUC1) was classified into apical, cytoplasmic and stromal types based on the predominant cellular distribution. The MUC1 mRNA levels revealed by in situ hybridization were not a determinant for the localization types of MY.1E12-MUC1. Immunostaining of MY.1E12-MUC1 was recognized in the cancerous epithelia of pT1 carcinoma in 61%, pT2 in 78%, pT3 in 98% and pT4 in 90% of the cases at the deepest invading sites. At the deepest invading sites, apical-type localization was found to predominate in pT1 carcinoma, but stromal-type localization was found to increase in pT2-4 carcinomas in parallel with the depth of invasion. The frequency of synchronous distant organ metastasis at the time of diagnosis tended to be higher in cases of pT3 and pT4 carcinomas in the stromal-type localization-dominant group than in cases in the apical-type localization-dominant group. The post-surgical survival outcome of cases of pT3 and pT4 carcinomas was significantly poorer in the former than in the latter (P = 0.002). The stromal-type localization of MY.1E12-MUC1 may be a phenotype serving as a unique biological feature associated with the tumor aggressiveness of advanced colon carcinoma.

Expression of MUC1 recognized by a monoclonal antibody MY.1E12 is a useful biomarker for tumor aggressiveness of carcinoma of the gallbladder.

The overall outcome of gallbladder carcinoma has not been favorable because of frequent recurrence at distant sites after surgery. A high-level expression of MUC1 recognized by a monoclonal antibody (mAb), MY.1E12, is correlated with poor survival in several types of carcinomas. There is a need to find new prognostic parameters that can give further insights into tumor aggressiveness of the disease. Immunohistochemistry was performed to determine the expression level of mAb MY.1E12-reactive-MUC1 (MY.1E12-MUC1) in 79 cases of gallbladder carcinoma of different depths of invasion and to determine the correlation of the expression level with clinicopathological findings. The cellular distribution of MY.1E12-MUC1 was heterogeneous among carcinomas of different depths of invasion. Immunohistochemical localization was classified into apical, cytoplasmic and stromal types based on the predominant cellular distribution. In 35 cases of pT2 carcinoma in which curative resections had been performed, the localization was apical type in 54%, cytoplasmic type in 66%, and stromal type in 56% of the cases at the deepest invading sites in the subserosal layer. Postsurgical recurrences at distant sites were seen in 11 of 18 cases of pT2 carcinoma (61%) that had more than or equal to 10% of the cancerous epithelia showing stromal localization of MY.1E12-MUC1 at the deepest invading sites (stromal group) and in 3 of 17 cases (18%) that had less than 10% of the cancerous epithelia showing stromal localization (nonstromal group). The postsurgical 5-year survival rate was significantly poorer in the former (54%) than in the latter (79%; P = 0.049). In 38 cases of pT3 and pT4 carcinomas, the frequency of synchronous distant organ metastasis at the time of diagnosis was significantly higher in cases in the stromal group (61%) than in cases in the nonstromal group (20%). Moreover, in 73 cases of pT2, pT3 and pT4 carcinomas, the expression rate of abnormal localization of E-cadherin was significantly higher in the stromal group (63%) than in the nonstromal group (30%). The MUC1 mRNA levels revealed by in situ hybridization would not be a determinant important for the stromal localization. The stromal localization of MY.1E12-MUC1 may be a phenotype serving as a unique biological feature associated with the tumor aggressiveness of gallbladder carcinoma, such as the tendency to form distant organ metastasis.

Expression of UDP-N-acetyl-alpha-D-galactosamine-polypeptide N-acetylgalactosaminyltransferase isozyme 3 in the subserosal layer correlates with postsurgical survival of pathological tumor stage 2 carcinoma of the gallbladder.

PURPOSE AND EXPERIMENTAL DESIGN: Little is known about the molecular events leading to the development and progression of pathological tumor stage 2 (pT(2)) gallbladder carcinoma. An alteration in the site of O-glycosylation may be associated with malignant behavior of carcinoma cells by modulation of the biological properties of the target mucin. The UDP-N-acetyl-alpha-D-galactosamine-polypeptide N-acetylgalactosaminyltransferase isozyme 3 (GalNAc-T3) has the epithelial gland-specific expression and catalyzes mucin-type O-glycosylation. In this study, immunohistochemistry was performed to determine the expression level of GalNAc-T3 in 34 cases of pT(2) gallbladder carcinoma to determine the correlation of the GalNAc-T3 expression level with mode of recurrence and postsurgical survival. RESULTS: The expression levels of GalNAc-T3 protein and mRNA were increased in gallbladder carcinomas compared with the levels in adjacent noncancerous tissues and in intact gallbladders. Immunostaining of GalNAc-T3 was recognized in the cancerous epithelia, and the subcellular localization was classified into granular and diffuse types. In the 34 cases of pT(2) carcinoma, the localization of GalNAc-T3 was granular type in 50% and diffuse type in 50% of the cases at the deepest invading sites in the subserosal layer. Postsurgical recurrence was significantly more frequent in cases showing diffuse-type localization of GalNAc-T3 at the deepest invading sites (65%) than in those showing granular-type localization (23%; P < 0.05). Postsurgical survival was significantly poorer in cases showing diffuse-type localization than in those showing granular-type localization (P = 0.033) CONCLUSIONS: In pT(2) gallbladder carcinoma, the presence of diffuse-type localization of GalNAc-T3 in the subserosal layer is correlated with aggressiveness of the disease. This phenotype may serve as a unique biological feature associated with the malignant behavior.