Prevalence of thyroid diffuse goiter and its association with body mass index and the presence of cysts and nodules in children and adolescents: the Fukushima Health Management Survey.

The main cause of diffuse thyroid goiter is autoimmune chronic thyroiditis, otherwise known as Hashimoto's thyroiditis. Thyroid hormones play pivotal roles in growth and development during childhood. However, the prevalence of diffuse goiter and the relationships between diffuse goiter, thyroid volume, cysts and nodules, and anthropometric measurements in children are not well known. Among 789,459 participants who participated in thyroid ultrasound examinations, 320,206 participants (male: 161,728; female: 158,478) aged 1-23 years were analyzed. Logistic regression analyses were conducted to calculate the odds ratios of the standard deviation score of body mass index (BMI-SDS), the SDS of bilateral width multiplied thickness area (BWTAR-SDS) as a provisional determination of thyroid volume, and the presence of nodules or cysts for positive diffuse goiter compared with negative diffuse goiter after correction for sex and age. The prevalence of diffuse goiter increased in a female-dominant manner with aging. Compared with the absence of diffuse goiter, the age- and sex-adjusted odds ratios (95% confidence intervals) for BMI-SDS (1 SD), BWTAR-SDS (1 SD), cysts, and nodules were 1.24 (1.21-1.27), 3.21 (3.13-3.29), 0.53 (0.50-0.58), and 1.38 (1.17-1.64), respectively. The odds ratios of nodules for positive diffuse goiter were 4.18 (1.08-16.08), 1.76 (1.01-3.07), 1.80 (1.32-2.45), and 1.34 (1.08-1.67) in the age groups 1-7, 8-11, 12-15, and 16-23 years, respectively. The age-dependent increase in the prevalence of diffuse goiter was independently associated with increased BMI and positive prevalence of nodules in young individuals.

Hyperthyroidism exacerbates ischemic reperfusion injury in the kidney.

Thyroid hormones are critical regulators of vertebrate development and metabolism. Under hyperthyroid conditions, excess thyroid hormones induce expression of several enzymes and activities via activation of ligand-bound thyroid hormone receptors (TRs). Arginase (ARG) is downstream of a ligand-bound TR and overexpression of ARG2 induces the production of reactive oxygen species and subsequent exacerbation of kidney ischemia/reperfusion (I/R) injury. To clarify the association between I/R-induced kidney injury and hyperthyroidism, mice were pretreated with L-thyroxine (LT4) or vehicle alone, then subjected to I/R. Proximal tubular cell-specific conditional knockout of thyroid hormone receptor ß (TRßcKO) mice was generated and the effects of I/R were analyzed. Hyperthyroidism enhanced tubular damage and fibrosis in the kidneys of mice after I/R. Hyperthyroidism induced tubular cell necroptosis following inflammatory cell accumulation in the kidney after I/R. ARG2 expressions and reactive oxygen species accumulated in the kidneys of hyperthyroid mice after I/R, but these changes were ameliorated in the kidneys of TRßcKO mice. Hyperthyroidism-enhanced kidney injury was ameliorated in the kidney of TRßcKO mice after I/R. These results suggest that excess thyroid hormones are disadvantageous for the kidney under ischemic stress. Overt hypothyroidism represents a severe thyroid hormone deficiency disease that requires LT4 treatment, while overreplacement or iatrogenic thyrotoxicosis might cause kidney injury.

Intelectin1 ameliorates macrophage activation via inhibiting the nuclear factor kappa B pathway.

Inteletin1 (Itln1) is an adipokine that is abundantly expressed in intestine, ovary, and lung. The expression levels of ITLN1 are decreased in the presence of diabetes or obesity, but the mechanisms of its production and function are still controversial. The aim of this study is to elucidate the mechanisms of ITLN1 synthesis and ITLN1-associated macrophage activation. To analyze the effects of high fat and high-carbohydrate diet (HFHCD) on the expression of ITLN1 in the intestine, the mice were fed a HFHCD for 8 weeks. HFHCD feeding enhanced the endoplasmic reticulum (ER)-stress in the intestine and inhibited the expression of Itln1 in the intestinal endocrine cells and lowered circulating ITLN1 levels. In contrast, treatment with a chemical chaperone and reduction of ER-stress restored the expression of Itln1 in the intestine of HFHCD-fed mice. Furthermore, in vitro studies indicated that ITLN1 physically interacts with adiponectin receptor 1 and suppresses lipopolysaccharide-induced mRNA expressions of pro-inflammatory cytokines and phagocytosis activities via inhibition of the nuclear factor kappa B-signaling pathway in macrophages. These results suggest that diet-induced ER-stress decreases circulating ITLN1 via inhibition of its synthesis in the intestine, and a reduction of circulating ITLN1 might enhanced the expression of proinflammatory cytokines and macrophage activation, following exacerbate the chronic inflammation of metabolic syndrome.

Hypoxia-induced thyroid hormone receptor expression regulates cell-cycle progression in renal tubule epithelial cells.

Hypoxia occurs in the kidneys of chronic kidney disease (CKD) patients, inducing interstitial fibrosis and tubule cell death. Renal tubule cell death is an important determinant of mortality in CKD. We focused on the regulation of cell-cycle-mediated protein expression to prevent cell death under chronic hypoxia in the kidneys of CKD patients. Paraffin-embedded kidney sections from patients with CKD (diabetes nephropathy, nephrosclerosis, or IgA nephropathy) were analyzed for the expression of hypoxia-inducible factor (HIF), thyroid hormone receptor (TR) ß, or p21 and levels of interstitial fibrosis. Human renal proximal tubule cells were exposed to hypoxia and analyzed for the expression of HIF, TRß, or p21 and the cell-cycle stage. TRß expression was enhanced early on when fibrosis was not fully developed in the tubule cells of CKD patients. HIF1α bound to the TRß promoter and directly induced its transcription. Further, HIF1α expression induced the expression of TRß and inhibited cell-cycle progression. In the early stage of kidney injury, TRß might act as a guardian to prepare and organize cell-cycle proliferation and prevent cell death. While the molecular mechanism that regulates the expression of cell-cycle regulators in renal tubule cells remains controversial, TRß has strong potential as a new therapeutic target.

Position paper from the Japan Thyroid Association task force on the management of low-risk papillary thyroid microcarcinoma (T1aN0M0) in adults.

The incidence of thyroid carcinoma has been increasing worldwide. This is interpreted as an increase in the incidental detection of papillary thyroid microcarcinomas (PTMCs). However, mortality has not changed, suggesting overdiagnosis and overtreatment. Prospective clinical trials of active surveillance for low-risk PTMC (T1aN0M0) have been conducted in two Japanese institutions since the 1990s. Based on the favorable outcomes of these trials, active surveillance has been gradually adopted worldwide. A task force on the management of PTMC in adults organized by the Japan Thyroid Association therefore conducted a systematic review and has produced the present position paper based on the scientific evidence concerning active surveillance. This paper indicates evidence for the increased incidence of PTMC, favorable surgical outcomes for low-risk PTMC, recommended criteria for diagnosis using fine needle aspiration cytology, and evaluation of lymph node metastasis (LNM), extrathyroidal extension (ETE) and distant metastasis. Active surveillance has also been reported with a low incidence of disease progression and no subsequent recurrence or adverse events on survival if conversion surgery was performed at a slightly advanced stage. Active surveillance is a safe and valid strategy for PTMC, because it might preserve physical quality of life and reduce 10-year medical costs. However, some points should be noted when performing active surveillance. Immediate surgery is needed for PTMC showing high-risk features, such as clinical LNM, ETE or distant metastasis. Active surveillance should be performed under an appropriate medical team and should be continued for life.

Calcitonin levels by ECLIA correlate well with RIA values in higher range but are affected by sex, TgAb, and renal function in lower range.

Calcitonin (CT) is a marker for both initial diagnosis and monitoring of patients with residual or recurrent medullary thyroid carcinoma (MTC). In Japan, serum CT had been measured by radioimmunoassay (RIA) until recently. Electrochemiluminescence immunoassay (ECLIA) became commercially available in 2014, and this technique is now the only method used to examine CT concentration. The purposes of this study were to investigate the correlations between the CT concentration measured with ECLIA (ECLIA-CT) and RIA (RIA-CT) and to explore the clinical characteristics of patients with elevated ECLIA-CT. CT concentrations of 348 sera samples from 334 patients with various thyroid disorders including nine MTC were measured using both assays. The correlation analysis revealed an excellent correlation between ECLIA-CT and RIA-CT among the cases with CT level >150 pg/mL by both assays (rs = 0.991, p < 0.001). However, 63% of all samples exhibited undetectable ECLIA-CT, while their RIA-CTs were measured between 15 and 152 pg/mL. The ECLIA-CTs in all patients who underwent total thyroidectomy for non-MTC showed low concentrations. High ECLIA-CT was observed in patients with MTC or pancreas neuroendocrine tumor. ECLIA-CT was also increased in 14 other male patients with non-MTC, including four with renal failure. Multivariate logistic regression analysis showed that male sex, negative TgAb, and lower estimated glomerular filtration rate were independent factors to predict detectable ECLIA-CT (≥0.500 pg/mL). These results indicate that ECLIA-CT correlates well with RIA-CT in higher range and is affected by sex, TgAb, and renal function.

Association between the Cardio-Ankle Vascular Index and Diabetes Mellitus-Related Peripheral Arterial Disease in Chronic Hemodialysis Patients.

BACKGROUND: Peripheral arterial disease (PAD) has increased in association with the increase in the numbers of patients with kidney disease or diabetes. The aim of this study was to assess the prevalence of PAD in hemodialysis patients with diabetes. METHODS: To examine the usefulness of the cardio-ankle vascular index (CAVI) to screen for the presence of PAD, cross-sectional studies of 100 patients undergoing chronic hemodialysis were performed. The CAVI and other inflammatory markers were evaluated. RESULTS: The CAVI was markedly elevated in patients with a history of PAD or cardiovascular disease. When dialysis patients were classified on the basis of CAVI quartiles, increased CAVI was associated with other risk factors for PAD. CONCLUSION: The prevalence of PAD is high in elderly diabetic patients on hemodialysis. The present findings suggest that the CAVI can be a useful index that predicts the occurrence of macrovascular complications in dialysis patients with diabetes.

Impaired oxidative endoplasmic reticulum stress response caused by deficiency of thyroid hormone receptor α.

Thyroid hormone receptor α (TRα) is critical to postnatal pancreatic ß-cell maintenance. To investigate the association between TRα and the survival of pancreatic ß-cells under endoplasmic reticulum (ER) stress, the expression of endogenous TRα was inhibited by infection with an adenovirus expressing double-stranded short hairpin RNA against TRα (AdshTRα). In control adenovirus-infected pancreatic ß-cells, palmitate enhanced the expression of activating transcription factor 4 (ATF4) and heme oxygenase 1, which facilitates adaptation to oxidative ER stress. However, in AdshTRα-infected pancreatic ß-cells, palmitate did not induce ATF4-mediated integrated stress response, and oxidative stress-associated apoptotic cell death was significantly enhanced. TRα-deficient mice or wild-type mice (WT) were fed a high fat diet (HFD) for 30 weeks, and the effect of oxidative ER stress on pancreatic ß-cells was analyzed. HFD-treated TRα-deficient mice had high blood glucose levels and low plasma insulin levels. In HFD-treated TRα-deficient mice, ATF4 was not induced, and apoptosis was enhanced compared with HFD-treated WT mice. Furthermore, the expression level of 8-hydroxydeoxyguanosine, an oxidative stress marker, was enhanced in the ß-cells of HFD-treated TRα-deficient mice. These results indicate that endogenous TRα plays an important role for the expression of ATF4 and facilitates reduced apoptosis in pancreatic ß-cells under ER stress.

Effects of 3,3',5-triiodothyronine on microglial functions.

L-tri-iodothyronine (3, 3', 5-triiodothyronine; T3) is an active form of the thyroid hormone (TH) essential for the development and function of the CNS. Though nongenomic effect of TH, its plasma membrane-bound receptor, and its signaling has been identified, precise function in each cell type of the CNS remained to be investigated. Clearance of cell debris and apoptotic cells by microglia phagocytosis is a critical step for the restoration of damaged neuron-glia networks. Here we report nongenomic effects of T3 on microglial functions. Exposure to T3 increased migration, membrane ruffling and phagocytosis of primary cultured mouse microglia. Injection of T3 together with stab wound attracted more microglia to the lesion site in vivo. Blocking TH transporters and receptors (TRs) or TRα-knock-out (KO) suppressed T3-induced microglial migration and morphological change. The T3-induced microglial migration or membrane ruffling was attenuated by inhibiting Gi /o -protein as well as NO synthase, and subsequent signaling such as phosphoinositide 3-kinase (PI3K), mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK). Inhibitors for Na(+) /K(+) -ATPase, reverse mode of Na(+) /Ca(2+) exchanger (NCX), and small-conductance Ca(2+) -dependent K(+) (SK) channel also attenuated microglial migration or phagocytosis. Interestingly, T3-induced microglial migration, but not phagocytosis, was dependent on GABAA and GABAB receptors, though GABA itself did not affect migratory aptitude. Our results demonstrate that T3 modulates multiple functional responses of microglia via multiple complex mechanisms, which may contribute to physiological and/or pathophysiological functions of the CNS.

Ligand-bound thyroid hormone receptor contributes to reprogramming of pancreatic acinar cells into insulin-producing cells.

One goal of diabetic regenerative medicine is to instructively convert mature pancreatic exocrine cells into insulin-producing cells. We recently reported that ligand-bound thyroid hormone receptor α (TRα) plays a critical role in expansion of the ß-cell mass during postnatal development. Here, we used an adenovirus vector that expresses TRα driven by the amylase 2 promoter (AdAmy2TRα) to induce the reprogramming of pancreatic acinar cells into insulin-producing cells. Treatment with l-3,5,3-triiodothyronine increases the association of TRα with the p85α subunit of phosphatidylinositol 3-kinase (PI3K), leading to the phosphorylation and activation of Akt and the expression of Pdx1, Ngn3, and MafA in purified acinar cells. Analyses performed with the lectin-associated cell lineage tracing system and the Cre/loxP-based direct cell lineage tracing system indicate that newly synthesized insulin-producing cells originate from elastase-expressing pancreatic acinar cells. Insulin-containing secretory granules were identified in these cells by electron microscopy. The inhibition of p85α expression by siRNA or the inhibition of PI3K by LY294002 prevents the expression of Pdx1, Ngn3, and MafA and the reprogramming to insulin-producing cells. In immunodeficient mice with streptozotocin-induced hyperglycemia, treatment with AdAmy2TRα leads to the reprogramming of pancreatic acinar cells to insulin-producing cells in vivo. Our findings suggest that ligand-bound TRα plays a critical role in ß-cell regeneration during postnatal development via activation of PI3K signaling.

Neutrophil gelatinase-associated lipocalin levels associated with cardiovascular disease in chronic kidney disease patients.

BACKGROUND: Elevated levels of neutrophil gelatinase-associated lipocalin (NGAL) have been reported in patients with cardiovascular disease (CVD), heart failure, and stroke. We assessed the relationships between serum levels of NGAL and the prevalence of CVD, and clarified the prognostic usefulness of systemic NGAL levels in hemodialysis (HD) patients. METHODS: Eighty-eight HD patients were followed up for 1 year. Logistic regression analyses were used to investigate the relationship between de novo CVD status and NGAL levels as well as other risk factors. RESULTS: During follow-up, CVD events occurred in 20 patients. Initial serum levels of NGAL and brain natriuretic peptide of HD patients with de novo CVD were significantly higher than those of HD patients without de novo CVD. Multivariate logistic regression analyses showed that initial serum levels of NGAL were independent risk factors for de novo CVD in HD patients. When patients were classified on the basis of NGAL quartiles, multiple logistic regression analyses demonstrated that the highest quartile of NGAL level showed an increased odds ratio for the prevalence of CVD. CONCLUSION: These findings suggest that NGAL levels can be used to detect the prevalence of CVD in HD patients with or without diabetes.

Effects of Overweight on Risk of Thyroid Nodules in Children and Adolescents: The Fukushima Health Management Survey.

CONTEXT: Examining how overweight/obesity impacts thyroid nodule development in children and adolescents by sex and age can speculate on the mechanism. OBJECTIVE: We examined whether overweight in children and adolescents are associated with thyroid nodule development by sex and age. DESIGN: Approximately 300,000 participants who underwent thyroid ultrasonography in the Fukushima Health Management Survey after a nuclear accident were enrolled. Those without nodules in the initial two examinations (1-3 and 4-5 years postaccident) were prospectively assessed for nodule development in the third examination (6-7 years postaccident) relative to baseline overweight status, with an average follow-up of 4.2 years. SETTING: A population-based prospective cohort study. PARTICIPANTS: The first and second thyroid examinations involved 299,939 and 237,691 participants, respectively, excluding those with thyroid nodules. After the third examination, 184,519 participants were finalized for analysis. MAIN OUTCOME MEASURES: Multivariable-adjusted odds ratios of new detected thyroid nodules for overweight participants compared with normal-weight participants. RESULTS: New thyroid nodules were detected in 660 participants. Being overweight was positively associated with thyroid nodules. The adjusted odds ratio (95% confidence interval) of thyroid nodules for overweight participants compared with other participants was 1.27 (1.04-1.57). Additionally, the multivariable-adjusted odds ratios for males and females with overweight were 1.21 and 1.32, respectively, and those for different age groups (0-9, 10-14, and 15-19 years) ranged from 1.17 to 1.75. CONCLUSIONS: Being overweight was associated with thyroid nodules in children and adolescents, mostly adolescent females, regardless of their proximity to the nuclear power plant.

Membrane protease prostasin promotes insulin secretion by regulating the epidermal growth factor receptor pathway.

Prostasin (PRSS8) is a serine protease that metabolizes and moderates the effect of specific substrates. Epidermal growth factor receptor (EGFR), which modulates insulin secretion and pancreatic ß-cell proliferation, is regulated via proteolytic shedding by PRSS8. We first detected PRSS8 expression in ß-cells of pancreatic islets of mice. To better understand the molecular processes involved in PRSS8-associated insulin secretion, pancreatic ß-cell-specific PRSS8 knockout (ßKO) and PRSS8-overexpressing (ßTG) male mice were generated. We found that glucose intolerance and reduction in glucose-stimulated insulin secretion developed in ßKO mice compared with the control subjects. A higher response to glucose was noted in islets retrieved from ßTG mice. Erlotinib, a specific blocker of EGFR, blocks EGF- and glucose-stimulated secretion of insulin among MIN6 cells, and glucose improves EGF release from ß-cells. After silencing PRSS8 in MIN6 cells, glucose-stimulated insulin secretion decreased, and EGFR signaling was impaired. Conversely, overexpression of PRSS8 in MIN6 cells induced higher concentrations of both basal and glucose-stimulated insulin secretion and increased phospho-EGFR concentrations. Furthermore, short-term exposure to glucose improved the concentration of endogenous PRSS8 in MIN6 cells through inhibition of intracellular degradation. These findings suggest that PRSS8 is involved in glucose-dependent physiological regulation of insulin secretion via the EGF-EGFR signaling pathway in pancreatic ß-cells.

Ultrasonography-based reference values for the cross-sectional area of the thyroid gland in children and adolescents: The Fukushima Health Management Survey.

We previously described the thyroid volume, which was calculated by measuring the thyroid width, thickness, and longitudinal length using ultrasonography, in children and adolescents. We have proposed a simplified method for quantitatively assessing the thyroid size, to overcome the inaccuracy and challenges in measuring the longitudinal length of the thyroid. Based on measurements of 317,847 (girls: 156,913, boys: 160,934) children and adolescents, we calculated sex-specific means and standard deviations of thyroid width and thickness, and of the cross-sectional area computed by multiplying them, for every age and 0.1 m2 of body surface area, after ensuring normal distribution with Box-Cox transformation. Multivariate regression analysis revealed that female sex, age, and body surface area were independently associated with areas of each thyroid lobe. Our novel method may be useful in quantitatively assessing the thyroid size, and appropriately diagnosing pathological conditions, such as hypoplasia, atrophy, and enlargement of the thyroid gland, in children and adolescents.

Possible Association Between Thyroid Nodule Formation and Developmental Alterations in the Pituitary-Thyroid Hormone Axis in Children and Adolescents: The Fukushima Health Management Survey.

Background: We previously found low thyrotropin (TSH) levels in children and adolescents with thyroid nodules, including papillary thyroid cancer, although it is generally accepted that high TSH levels are a risk factor for formation and growth of thyroid nodules in adults. To clarify the reasons for the discrepancy, we precisely analyzed the features of pituitary-thyroid hormone (TH) actions in children and adolescents with or without nodules at different ages. Methods: Among the 4955 participants who participated in a second screening by thyroid ultrasound examination in the Fukushima Health Management Survey, 721 and 2849 euthyroid participants aged 6-20 years without or with nodules, including thyroid cancer, were selected for evaluation of TH regulation. The responsivity of TSH to THs was assessed by two thyroid feedback quantile-based indices (T4FQI and T3FQI). Logistic regression analyses were conducted to calculate the odds ratios (ORs) of serum concentrations related to thyroid functions for positive thyroid nodules compared with negative nodules. Results: The feedback indices declined in a sex-specific manner with aging. In particular, T3FQI, the index for TSH response to free triiodothyronine (fT3), started to decline after ∼10 and 15 years of age in female and male participants, respectively. Compared with the absence of nodules, the age- and sex-adjusted ORs (confidence intervals) for logTSH, free thyroxine (fT4), fT3, T4FQI, T3FQI, and thyroglobulin levels were 0.586 (0.501-0.685), 1.036 (0.595-1.805), 1.059 (0.842-1.332), 0.569 (0.454-0.715), 0.564 (0.443-0.719), and 1.01 (1.005-1.014), respectively. Associations between the presence of nodules and either low logTSH or low feedback indices were observed in participants aged between 12 and 17 years among the total cohort. Conclusions: The relationships between the levels of TSH and THs changed in a sex-dependent manner in children and adolescents. The age-dependent shift in the pituitary-TH set point may be associated with age-dependent nodule formation during restricted periods of growth and maturation in both young female and male participants.

Liganded thyroid hormone receptor-alpha enhances proliferation of pancreatic beta-cells.

Failure of the functional pancreatic beta-cell mass to expand in response to increased metabolic demand is a hallmark of type 2 diabetes. Lineage tracing studies indicate that replication of existing beta-cells is important for beta-cell proliferation in adult animals. In rat pancreatic beta-cell lines (RIN5F), treatment with 100 nM thyroid hormone (triiodothyronine, T(3)) enhances cell proliferation. This result suggests that T(3) is required for beta-cell proliferation or replication. To identify the role of thyroid hormone receptor alpha (TR(alpha)) in the processes of beta-cell growth and cell cycle regulation, we constructed a recombinant adenovirus vector, AdTR(alpha). Infection with AdTR(alpha) to RIN5F cells increased the expression of cyclin D1 mRNA and protein. Overexpression of the cyclin D1 protein in AdTR(alpha)-infected cells led to activation of the cyclin D1/cyclin-dependent kinase/retinoblastoma protein/E2F pathway, along with cell cycle progression and cell proliferation following treatment with 100 nM T(3). Conversely, lowering cellular cyclin D1 by small interfering RNA knockdown in AdTR(alpha)-infected cells led to down-regulation of the cyclin D1/CDK/Rb/E2F pathway and inhibited cell proliferation. Furthermore, in immunodeficient mice with streptozotocin-induced diabetes, intrapancreatic injection of AdTR(alpha) led to the restoration of islet function and to an increase in the beta-cell mass. These results support the hypothesis that liganded TR(alpha) plays a critical role in beta-cell replication and in expansion of the beta-cell mass during postnatal development. Thus, liganded TR(alpha) may be a target for therapeutic strategies that can induce the expansion and regeneration of beta-cells.

NKX2-1 re-expression induces cell death through apoptosis and necrosis in dedifferentiated thyroid carcinoma cells.

NK2 homeobox 1 (NKX2-1) is a thyroid transcription factor essential for proper thyroid formation and maintaining its physiological function. In thyroid cancer, NKX2-1 expression decreases in parallel with declined differentiation. However, the molecular pathways and mechanisms connecting NKX2-1 to thyroid cancer phenotypes are largely unknown. This study aimed to examine the effects of NKX2-1 re-expression on dedifferentiated thyroid cancer cell death and explore the underlying mechanisms. A human papillary thyroid carcinoma cell line lacking NKX2-1 expression was infected with an adenoviral vector containing Nkx2-1. Cell viability decreased after Nkx2-1 transduction and apoptosis and necrosis were detected. Arginase 2 (ARG2), regulator of G protein signaling 4 (RGS4), and RGS5 mRNA expression was greatly increased in Nkx2-1-transducted cells. After suppressing these genes by siRNA, cell death, apoptosis, and necrosis decreased in RGS4 knockdown cells. These findings demonstrated that cell death was induced via apoptosis and necrosis by NKX2-1 re-expression and involves RGS4.

Membranous Nephropathy with Proteinase 3-ANCA-associated Vasculitis Successfully Treated with Rituximab.

Membranous nephropathy (MN) with anti-neutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis (ANCA-GN) is seen infrequently. Previous reports of patients with ANCA-GN with MN showed that the most frequent ANCA subtype was myeloperoxidase-ANCA. We herein present a 73-year-old woman with scleritis, hematuria, proteinuria, and positive serum proteinase 3 (PR3)-ANCA. She underwent a renal biopsy and was diagnosed with MN and ANCA-GN. Immunofluorescence staining for PR3 colocalized with IgG along the glomerular basement membrane were observed. Oral prednisolone and intravenous rituximab therapy immediately improved her symptoms and urinalysis abnormalities. PR3-ANCA may be involved in the pathogenesis of MN via the formation of immune complexes.

Impaired adipogenesis caused by a mutated thyroid hormone alpha1 receptor.

Thyroid hormone (T3) is critical for growth, differentiation, and maintenance of metabolic homeostasis. Mice with a knock-in mutation in the thyroid hormone receptor alpha gene (TRalpha1PV) were created previously to explore the roles of mutated TRalpha1 in vivo. TRalpha1PV is a dominant negative mutant with a frameshift mutation in the carboxyl-terminal 14 amino acids that results in the loss of T3 binding and transcription capacity. Homozygous knock-in TRalpha1(PV/PV) mice are embryonic lethal, and heterozygous TRalpha1(PV/+) mice display the striking phenotype of dwarfism. These mutant mice provide a valuable tool for identifying the defects that contribute to dwarfism. Here we show that white adipose tissue (WAT) mass was markedly reduced in TRalpha1(PV/+) mice. The expression of peroxisome proliferator-activated receptor gamma (PPARgamma), the key regulator of adipogenesis, was repressed at both mRNA and protein levels in WAT of TRalpha1(PV/+) mice. Moreover, TRalpha1PV acted to inhibit the transcription activity of PPARgamma by competition with PPARgamma for binding to PPARgamma response elements and for heterodimerization with the retinoid X receptors. The expression of TRalpha1PV blocked the T3-dependent adipogenesis of 3T3-L1 cells and repressed the expression of PPARgamma. Thus, mutations of TRalpha1 severely affect adipogenesis via cross talk with PPARgamma signaling. The present study suggests that defects in adipogenesis could contribute to the phenotypic manifestation of reduced body weight in TRalpha1(PV/+) mice.

Nuclear receptor corepressor is a novel regulator of phosphatidylinositol 3-kinase signaling.

The nuclear receptor corepressor (NCoR) regulates the activities of DNA-binding transcription factors. Recent observations of its distribution in the extranuclear compartment raised the possibility that it could have other cellular functions in addition to transcription repression. We previously showed that phosphatidylinositol 3-kinase (PI3K) signaling is aberrantly activated by a mutant thyroid hormone beta receptor (TRbetaPV, hereafter referred to as PV) via physical interaction with p85alpha, thus contributing to thyroid carcinogenesis in a mouse model of follicular thyroid carcinoma (TRbetaPV/PV mouse). Since NCoR is known to modulate the actions of TRbeta mutants in vivo and in vitro, we asked whether NCoR regulates PV-activated PI3K signaling. Remarkably, we found that NCoR physically interacted with and competed with PV for binding to the C-terminal SH2 (Src homology 2) domain of p85alpha, the regulatory subunit of PI3K. Confocal fluorescence microscopy showed that both NCoR and p85alpha were localized in the nuclear as well as in the cytoplasmic compartments. Overexpression of NCoR in thyroid tumor cells of TRbetaPV/PV mouse reduced PI3K signaling, as indicated by the decrease in the phosphorylation of its immediate downstream effector, p-AKT. Conversely, lowering cellular NCoR by siRNA knockdown in tumor cells led to overactivated p-AKT and increased cell proliferation and motility. Furthermore, NCoR protein levels were significantly lower in thyroid tumor cells than in wild-type thyrocytes, allowing more effective binding of PV to p85alpha to activate PI3K signaling and thus contributing to tumor progression. Taken together, these results indicate that NCoR, via protein-protein interaction, is a novel regulator of PI3K signaling and could serve to modulate thyroid tumor progression.