The NF-κB pathway is a central signaling pathway for inflammatory and immune responses, and aberrant NF-κB signaling is implicated multiple disorders, such as cancer and autoimmune, chronic inflammatory and metabolic diseases. NF-κB is regulated by various post-translational modifications, including phosphorylation and multiple ubiquitinations. We determined that LUBAC (linear ubiquitin chain assembly complex), composed of SHARPIN, HOIL-IL and HOIP, generates a novel type of Met1-linked linear polyubiquitin chain and specifically regulates the canonical NF-κB pathway via the linear ubiquitination of NEMO and RIP1. In the absence of LUBAC components, NF-κB signaling was attenuated and induced apoptosis and inflammation. Many studies on the pathophysiological functions of LUBAC, such as in B cell development, innate immune response, carcinogenesis, and osteogenesis, have been performed recently. This review summarizes these new findings on LUBAC- and linear ubiquitination-mediated NF-κB regulation and their implications in disorders.
The transforming growth factor (TGF)-β family members, bone morphogenetic protein (BMP)-2 and TGF-β that signal via the receptor-regulated Smads (R-Smads) induce bone formation in vivo. The inhibitory Smads (I-Smads), Smad6 and Smad7, negatively regulate TGF-β family ligand signaling by competing with R-Smads for binding to activated type I receptors, and preventing R-Smad activation, Hence, the I-Smads potentially act as suppressors of bone formation although their effects on phenotypic changes in mature osteoblasts are unclear. While Smad7 inhibits both BMP and TGF-β signaling, Smad6 is less effective in inhibiting TGF-β signaling. The present study was performed to examine the role of Smad7 on the phenotype of mouse osteoblastic MC3T3-E1 cells. We employed stable Smad7-transfected MC3T3-E1 cells to examine the role of Smad7 in osteoblast proliferation, differentiation and mineralization. Stable Smad7 overexpression significantly inhibited the absorbance in the MTT-dye assay and inhibited the levels of PCNA compared with those in empty vector-transfected cells. Smad7 overexpression suppressed the type 1 collagen mRNA and protein levels. Moreover, Smad7 inhibited ALP activity and mineralization of osteoblastic cells. The effects of stable overexpression of Smad6 were similar to those of Smad7 suggesting the changes mediated by either I-Smad occurred by inhibition of BMP rather than TGF-β signaling. In addition, PTH-(1-34) elevated the levels of Smad7 in parental MC3T3-E1 cells. In conclusion, the present study demonstrated that Smad7, as well as Smad6, inhibits proliferation, differentiation and mineralization of mouse osteoblastic cells. Therefore, I-Smads are important molecular targets for the negative control of bone formation.
The syndrome of inappropriate secretion of thyrotropin (SITSH) is defined as the inappropriate non-suppression of serum TSH in the presence of elevated free thyroid hormone; TSH-secreting pituitary adenomas and the syndrome of resistance to thyroid hormone are the main etiologies of SITSH. In addition, erroneous thyroid function testing may result in the diagnosis of this syndrome. A 63-year-old woman was referred because of suspected SITSH. Laboratory tests showed a normal TSH (0.52 μIU/L; normal range: 0.5-5.0) measured by sandwich Elecsys, and elevated FT4 (3.8 ng/dL; normal range: 0.9-1.6) and FT3 (7.6 pg/mL; normal range: 2.3-4.0), determined by competitive Elecsys. To exclude possible assay interference, aliquots of the original samples were retested using a different method (ADVIA Centaur), which showed normal FT4 and FT3 levels. Eight hormone levels, other than thyroid function tests measured by competitive or sandwich Elecsys, were higher or lower than levels determined by an alternative analysis. Subsequent examinations, including gel filtration chromatography, suggested interference by substances against ruthenium, which reduced the excitation of ruthenium, and resulted in erroneous results. The frequency of similar cases, where the FT4 was higher than 3.2 ng/dL, in spite of a non-suppressed TSH, was examined; none of 10 such subjects appeared to have method-specific interference. Here, a patient with anti-ruthenium interference, whose initial thyroid function tests were consistent with SITSH, is presented. This type of interference should be considered when thyroid function is measured using the Elecsys technique, although the frequency of such findings is likely very low.
Glycogenic hepatopathy (GH) has been reported as a very rare and under recognized complication in long-standing poorly controlled type 1 diabetes (T1D) patients. GH is characterized by transient elevation of liver transaminase and hepatomegaly caused by reversible and excessive glycogen accumulation in hepatocytes. It has been reported that GH is indistinguishable from non-alcoholic fatty liver disease, which is more commonly seen in diabetic patients, even after a history is taken and a physical examination or imaging studies have been performed. GH can only be diagnosed by liver biopsy. We here demonstrate a 21-year-old male patient with new-onset fulminant T1D complicated with diabetic ketoacidosis who subsequently developed GH just after the initiation of insulin treatment. The marked liver dysfunction (serum levels of aspartate aminotransferase 769 IU/L and alanine aminotransferase 1348 IU/L) and hepatomegaly improved spontaneously via glycemic control without any specific treatments thereafter. Moreover, the insulin requirement dramatically decreased from 168 to 80 units per day as GH improved, suggesting a potential role of GH in insulin resistance. GH was diagnosed based on the histological findings of the liver in our case, but we were able to predict GH before the biopsy based on the findings in the gradient-dual-echo magnetic resonance imaging sequence combined with ultrasound and/or computed tomography examinations of the liver.
GLUT4 is a major mediator of glucose removal from the circulation and a key regulator of whole-body glucose homeostasis. Recent studies in south Indian populations revealed that haplotypes of the GLUT4 gene associated with type 2 diabetes. A total of 734 middle aged apparently healthy Japanese men were recruited from two separate occupational cohorts from Kanagawa and Kyoto. Participants were genotyped for GLUT4 variants, rs5418 (A/G) and rs2654185 (C/A), and association with HbA1c level was analyzed. The HbA1c value was determined by JDS method which is 0.4% lower than NGSP value. The G allele carrier of rs5418 and A allele carrier of rs2654185 associated with significantly higher HbA1c level (AG + GG vs. AA carriers; 5.2 ± 0.8 vs. 4.9 ± 0.4, P < 0.002, and AA + AC vs. CC; 5.2 ± 0.9, vs. 4.9 ± 0.4, P < 0.002, respectively). G allele, AG + GG genotype of rs5418 and A allele, AA + AC genotype of rs2654185 showed a significant association with higher HbA1c (β = 0.215, P = 0.026; β = 0.215, P = 0.026; β = 0.190, P = 0.042; β = 0.190, P = 0.042, respectively). These two SNPs are in high linkage disequilibrium (LD) of r2 = 0.67. In haplotype analysis, four haplotypes were estimated. HbA1c is significantly higher in the most frequent GA haplotype compared with the second frequent AC haplotype (5.2% vs. 5.1%, P = 0.004). Genetic variations, rs5418 and rs2654185 in GLUT4 gene are associated with HbA1c level in Japanese men.
In patients with end-stage renal disease (ESRD), circulating adipokine levels are increased due to decreased renal clearance, irrespective of obesity. However, whether adipokines play a role in the development of insulin resistance (IR) in non-obese ESRD patients is unknown. We conducted a cross-sectional study to identify factors associated with IR in 62 non-obese patients on peritoneal dialysis (PD). Non-obesity was defined as body mass index (BMI) <25 kg/m². IR was determined using homeostatic model assessment-IR (HOMA-IR). We also measured serum concentrations of adiponectin, leptin, resistin, high-sensitivity C-reactive protein (hsCRP), and IL-6. The average BMI of the study patients was 21.6 kg/m². When patients were divided into two groups according to the median value of HOMA-IR, serum adiponectin levels were significantly lower in patients with HOMA-IR > 1.85 than in those with HOMA-IR ≤1.85, whereas serum concentrations of leptin and resistin did not differ between the two groups. In addition, log-transformed HOMA-IR was negatively correlated with adiponectin (γ = -0.464, P < 0.001) and log-transformed high-density lipoprotein cholesterol (γ = -0.250, P = 0.050) and positively correlated with age (γ = 0.334, P = 0.008) and triglyceride (γ = 0.392, P = 0.002). However, resistin, log-transformed leptin and log-transformed hsCRP were not associated with HOMA-IR. In a multiple linear regression model, adiponectin was independently associated with HOMA-IR (β = -0.023, P = 0.015). In conclusion, this study suggests that low circulating adiponectin levels might be involved in IR even in non-obese patients undergoing PD.
Iodine concentrations of enteral nutrition (EN) formulae available in Japan are very low and long-term total EN (TEN) might result in hypothyroidism due to iodine deficiency (HID). Our aim of this study was to determine the degree of iodine deficiency (ID) and need for iodine supplementation (IS) in patients with severe motor and intellectual disabilities (SMID) on long-term TEN. Thyroid function including urinary iodine concentration (UIC) was monitored, and powdered kelp was provided as a source of iodine supplement. Thirty-five SMID on TEN participated in our study. UIC less than 100 μg /L, representing ID, were detected in 97 % of them. Their TSH ranged from 0.5 to 90 μIU/mL. IS using powdered kelp raised their UIC to the normal range. Thyroid function also recovered in the five hypothyroidism cases, which were diagnosed as HID, was also detected. In Japan, there must be many cases with ID associated with long term TEN. We also discuss the regulation of thyroid function in the iodine deficient state.
Depression and chronic autoimmune thyroiditis are common diseases. The aim of this study was to determine whether the frequency of depression is elevated in patients with chronic autoimmune thyroiditis and normal thyroid function. A total of 201 subjects were included, of whom 107 and 94 participants were healthy or had euthyroid chronic autoimmune thyroiditis, respectively. Serum thyroid hormone levels and thyroid auto-antibodies were measured in all subjects. All participants were evaluated with Hamilton Depression Rating Scale (HDRS). HDRS scores of patients with euthyroid chronic autoimmune thyroiditis were higher than in healthy participants. This study suggests a possible association between depression and chronic autoimmune thyroiditis. The depression risk may be increased in patients with chronic autoimmune thyroiditis and normal thyroid function.
Sarpogrelate, a selective 5-HT2 receptor antagonist, is known to have a significant effect on antiplatelet action. This study was a double-blinded, randomized, paralleled multicenter trial to compare the effects of sarpogrelate and aspirin on preventing macrovascular complications in patients with type 2 diabetes. The subjects were randomly assigned to either the sarpogrelateor the aspirin group. The baseline parameters for macrovascular complications, such as intima media thickness (IMT), ankle-brachial index (ABI), IL-6, serotonin, adiponectin, and hsCRP, were measured before drug administration. Changes were compared at 6 and 12 months after the administration of each drug. A total of 127 subjects (63 in the sarpogrelate group and 64 in the aspirin group) were pooled during the study period. No significant differences were found in baseline IMT or in other predictors of macrovascular complications. The mean IMT increased in both groups after 12 months, but there was no significant difference between the two groups. No significant change was found in the other predictors of macrovascular complications nor in the incidence of drug-related adverse events between the two groups. During the study period, no significant differences were found between the sarpogrelate group and aspirin group in the clinical indices or in the safety of the subjects related to macrovascular complications. This suggests that sarpogrelate may be clinically useful for the primary prevention of macrovascular complications in patients with type 2 diabetes.
Autoimmune thyroid disease (AITD) is a multifactorial disease with a genetic susceptibility and environmental factors. The thyroid stimulating hormone receptor gene (TSHR) which is expressed on the surface of the thyroid epithelial cell is thought to be the main auto-antigen and a significant candidate for genetic susceptibility to AITD. This case-control study aimed at evaluating the association between single nucleotide polymorphisms (SNP) of TSHR and AITD in a Chinese Han population. We recruited 404 patients with Graves’ disease (GD), 230 patients with Hashimoto’s thyroiditis (HT) and 242 healthy controls. The Matrix Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometer (MALDI-TOF-MS) Platform was used to detect five SNPs (rs179247, rs12101255, rs2268475, rs1990595, and rs3783938) in TSHR gene. The frequencies of allele T and TT genotype of rs12101255 in GD patients were significantly increased compared with those of the controls (P=0.004/0.015, OR=1.408/1.446). The allele A frequency of rs3783938 was greater in HT patients than in the controls (P=0.025, OR=1.427). The AT haplotype (rs179247-rs12101255) was associated with an increased risk of GD (P=0.010, OR=1.368). The allele A of rs179247 was associated with ophthalmopathy in GD patients. These data suggest that the polymorphisms of rs12101255 and rs3783938 are associated with GD and HT, respectively.
Small for gestational age (SGA) at birth and postnatal growth pattern may have an impact on insulin resistance and body composition in their later life. Emerging evidence has indicated that insulin-like growth factor binding protein-2 (IGFBP-2) may be related to insulin sensitivity. The aim of this study was to evaluate insulin resistance and IGFBP-2 levels in SGA children, and to identify the effect of catch-up growth on IGFBP-2 concentration. Serum IGFBP-2 levels were measured in 103 Korean SGA children including 49 prepubertal and 54 pubertal subjects. Anthropometric values, fasting serum levels of metabolic parameters and insulin sensitivity indices were determined. Each prepubertal or pubertal group was subgrouped based on height or weight catch-up growth. The subgroups with weight catch-up showed higher values of BMI, body fat mass, percent body fat, and total cholesterol. Particularly in pubertal children, IGFBP-2 concentration was lower in the subgroup with weight catch-up. Catch-up growth in height did not affect insulin resistance and metabolic parameters. IGFBP-2 levels were inversely correlated with BMI, body fat mass, percent body fat, insulin and leptin levels in both prepubertal and pubertal groups. Additionally in the pubertal group, systolic blood pressure, cholesterol levels were related to IGFBP-2. A strong relationship between IGFBP-2, the insulin sensitivity index, and some cardiovascular risk factors was observed in children born SGA, suggesting that IGFBP-2 might be a promising marker for early recognition of insulin resistance, particularly in children with weight catch-up.
Adrenal aldosterone-producing adenomas (APA) are rarely associated with the clear co-secretion of cortisol. Somatic mutations of the potassium channel KCNJ5 gene, with the hotspots G151R and L168R, have been recently identified in patients with APA. However, whether APAs that secrete cortisol have these mutations remains unclear. We examined three patients with APAs showing clear autonomous secretion of cortisol who possessed a 1 mg dexamethasone suppression test (DST) with a failure of the serum cortisol level to drop below 3.0 μg/dL, a morning plasma ACTH level of less than 10 pg/mL, and suppressed accumulation in the intact adrenal on 131I- adosterol scintigraphy, or postoperative adrenal insufficiency. Laparoscopic adrenectomy revealed all tumors to be golden yellow, and histological examination confirmed them to be adrenocortical adenomas. All these patients required replacement therapy with hydrocortisone after surgery. Sequencing demonstrated that 2 of three cases showed a mutation of the KCNJ5 gene, one with c.451G>A, p.G151R and one with c.503T>G, p.L168R. Furthermore, the mRNA levels of steroidogenic enzymes including CYP11B1, CYP11B2, HSD3B2, CYP17A1, CYP11A1 and KCNJ5 in the 3 cases did not differ from those in 8 pure APAs not showing any of the above conditions for autonomous cortisol secretion. In addition, all 8 pure APAs harbored mutations of the KCNJ5 gene. These findings suggested that at least some aldosterone- and cortisol-co-secreting adrenal tumors have mutations of the KCNJ5 gene, suggesting the origin to be APA, and pure APAs may show a high incidence of KCNJ5 mutations.