Endoplasmic reticulum (ER) is the site of synthesis and folding of secretory proteins. Perturbations of ER homeostasis affect protein folding and cause ER stress. ER can sense the stress and respond to it through translational attenuation, upregulation of the genes for ER chaperones and related proteins, and degradation of unfolded proteins by a quality-control system. However, when the ER function is severely impaired, the organelle elicits apoptotic signals. ER stress has been implicated in a variety of common diseases such as diabetes, ischemia and neurodegenerative disorders. One of the components of the ER stress-mediated apoptosis pathway is C/EBP homologous protein (CHOP), also known as growth arrestand DNA damage-inducible gene 153 (GADD153). Here, we summarize the current understanding of the roles of CHOP/ GADD153 in ER stress-mediated apoptosis and in diseases including diabetes, brain ischemia and neurodegenerative disease.
The brain hypothalamus contains certain secreted molecules that are important in regulating feeding behaviour. Here we show that nesfatin, corresponding to NEFA/nucleobindin2 (NUCB2), a secreted protein of unknown function, is expressed in the appetite-control hypothalamic nuclei in rats. Intracerebroventricular (i.c.v.) injection of NUCB2 reduces feeding. Rat cerebrospinal fluid contains nesfatin-1, an amino-terminal fragment derived from NUCB2, and its expression is decreased in the hypothalamic paraventricular nucleus under starved conditions. I.c.v. injection of nesfatin-1 decreases food intake in a dose-dependent manner, whereas injection of an antibody neutralizing nesfatin-1 stimulates appetite. In contrast, i.c.v. injection of other possible fragments processed from NUCB2 does not promote satiety, and conversion of NUCB2 to nesfatin-1 is necessary to induce feeding suppression. Chronic i.c.v. injection of nesfatin-1 reduces body weight, whereas rats gain body weight after chronic i.c.v. injection of antisense morpholino oligonucleotide against the gene encoding NUCB2. Nesfatin-1-induced anorexia occurs in Zucker rats with a leptin receptor mutation, and an anti-nesfatin-1 antibody does not block leptin-induced anorexia. In contrast, central injection of alpha-melanocyte-stimulating hormone elevates NUCB2 gene expression in the paraventricular nucleus, and satiety by nesfatin-1 is abolished by an antagonist of the melanocortin-3/4 receptor. We identify nesfatin-1 as a satiety molecule that is associated with melanocortin signalling in the hypothalamus.
for the Japan Thyroid Association Background: Thyroid storm (TS) is life threatening. Its incidence is poorly defined, few series are available, and population-based diagnostic criteria have not been established. We surveyed TS in Japan, defined its characteristics, and formulated diagnostic criteria, FINAL-CRITERIA1 and FINAL-CRITERIA2, for two grades of TS, TS1, and TS2 respectively. Methods: We first developed diagnostic criteria based on 99 patients in the literature and 7 of our patients (LIT-CRITERIA1 for TS1 and LIT-CRITERIA2 for TS2). Thyrotoxicosis was a prerequisite for TS1 and TS2 as well as for combinations of the central nervous system manifestations, fever, tachycardia, congestive heart failure (CHF), and gastrointestinal (GI)/hepatic disturbances. We then conducted initial and follow-up surveys from 2004 through 2008, targeting all hospitals in Japan, with an eight-layered random extraction selection process to obtain and verify information on patients who met LIT-CRITERIA1 and LIT-CRITERIA2. Results: We identified 282 patients with TS1 and 74 patients with TS2. Based on these data and information from the Ministry of Health, Labor, and Welfare of Japan, we estimated the incidence of TS in hospitalized patients in Japan to be 0.20 per 100,000 per year. Serum-free thyroxine and free triiodothyroine concentrations were similar among patients with TS in the literature, Japanese patients with TS1 or TS2, and a group of patients with thyrotoxicosis without TS (Tox-NoTS). The mortality rate was 11.0% in TS1, 9.5% in TS2, and 0% in Tox-NoTS patients. Multiple organ failure was the most common cause of death in TS1 and TS2, followed by CHF, respiratory failure, arrhythmia, disseminated intravascular coagulation, GI perforation, hypoxic brain syndrome, and sepsis. Glasgow Coma Scale results and blood urea nitrogen (BUN) were associated with irreversible damages in 22 survivors. The only change in our final diagnostic criteria for TS as compared with our initial criteria related to serum bilirubin concentration > 3 mg/dL. Conclusions: TS is still a life-threatening disorder with more than 10% mortality in Japan. We present newly formulated diagnostic criteria for TS and clarify its clinical features, prognosis, and incidence based on nationwide surveys in Japan. This information will help diagnose TS and in understanding the factors contributing to mortality and irreversible complications. 1 The First Department of Medicine, Wakayama Medical University, Wakayama, Japan. 2 Department of Medicine and Molecular Science, Gunma University Graduate School of Medicine, Maebashi, Japan. 3 Department of Medicine 2, Tokyo Women's Medical University, Tokyo, Japan. 4 Division of Endocrinology and Metabolism, Department of Internal Medicine, Fujita Health University, Toyoake, Japan. 5 Department of Internal Medicine, Keio University, Tokyo, Japan. 6 Department of Clinical and Molecular Endocrinology, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan. 7 Division of Diabetes, Metabolism, and Endocrinolog...
Excessive nitric oxide (NO) production in cytokine-activated  cells has been implicated in  cell disruption in type 1 diabetes.  cells are very vulnerable to NO-induced apoptosis. However, the mechanism underlying this phenomenon is unclear. Low concentrations of NO that lead to apoptosis apparently do not cause severe DNA damage in mouse MIN6  cells. CHOP, a C͞EBP homologous protein that is induced by endoplasmic reticulum (ER) stress and plays a role in growth arrest and cell death, was induced by a NO donor, S-nitroso-N-acetyl-D,L-penicillamine (SNAP). SNAP increased cytosolic Ca 2؉ , and only agents depleting ER Ca 2؉ induced CHOP expression and led to apoptosis, suggesting that NO depletes ER Ca 2؉ . Overexpression of calreticulin increased the Ca 2؉ content of ER and afforded protection to cells against NO-mediated apoptosis. Furthermore, pancreatic islets from CHOP knockout mice showed resistance to NO. We conclude that NO depletes ER Ca 2؉ , causes ER stress, and leads to apoptosis. Thus, ER Ca 2؉ stores are a new target of NO, and the ER stress pathway is a major mechanism of NO-mediated  cell apoptosis.
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