Thiamine deficiency induces anorexia by inhibiting hypothalamic AMPK.

Obesity and eating disorders are prevailing health concerns worldwide. It is important to understand the regulation of food intake and energy metabolism. Thiamine (vitamin B1) is an essential nutrient. Thiamine deficiency (TD) can cause a number of disorders in humans, such as Beriberi and Wernicke-Korsakoff syndrome. We demonstrated here that TD caused anorexia in C57BL/6 mice. After feeding a TD diet for 16days, the mice displayed a significant decrease in food intake and an increase in resting energy expenditure (REE), which resulted in a severe weight loss. At the 22nd day, the food intake was reduced by 69% and 74% for male and female mice, respectively in TD group. The REE increased by ninefolds in TD group. The loss of body weight (17-24%) was similar between male and female animals and mainly resulted from the reduction of fat mass (49% decrease). Re-supplementation of thiamine (benfotiamine) restored animal's appetite, leading to a total recovery of body weight. The hypothalamic adenosine monophosphate-activated protein kinase (AMPK) is a critical regulator of food intake. TD inhibited the phosphorylation of AMPK in the arcuate nucleus (ARN) and paraventricular nucleus (PVN) of the hypothalamus without affecting its expression. TD-induced inhibition of AMPK phosphorylation was reversed once thiamine was re-supplemented. In contrast, TD increased AMPK phosphorylation in the skeletal muscle and upregulated the uncoupling protein (UCP)-1 in brown adipose tissues which was consistent with increased basal energy expenditure. Re-administration of thiamine stabilized AMPK phosphorylation in the skeletal muscle as well as energy expenditure. Taken together, TD may induce anorexia by inhibiting hypothalamic AMPK activity. With a simultaneous increase in energy expenditure, TD caused an overall body weight loss. The results suggest that the status of thiamine levels in the body may affect food intake and body weight.

Improvement of cognitive deficits in SAMP8 mice by 3-n-butylphthalide.

The herbal extract 3-n-butylphthalide (NBP) is used in clinical practice for ischemic patients in China. It has been shown to have various neuroprotective effects both in vitro and in vivo. In the present study, the effects of NBP on learning and memory decline in the senescence-accelerated mouse prone-8 (SAMP8) animal model were investigated. Intragastric NBP administration to 4-month-old SAMP8 mice for 2 months significantly improved spatial learning and memory ability. Moreover, the loss of choline acetyltransferase (ChAT)-positive neurons in the medial septal nucleus and the vertical limb of the diagonal band in SAMP8 mice was slowed down, as was the decline in the protein and mRNA expression of ChAT in the hippocampus, cerebral cortex, and forebrain. These results demonstrated that NBP treatment starting at the age of 4 months protected from the learning/memory deficits with aging of SAMP8 mice, and that this effect might be mediated by preventing the decline of the central cholinergic system.

The resveratrol attenuates ethanol-induced hepatocyte apoptosis via inhibiting ER-related caspase-12 activation and PDE activity in vitro.

BACKGROUND: Endoplasmic reticulum (ER) stress plays a key role in cell apoptosis pathways. Caspase-12, a proapoptotic gene induced by ER stress, is also the key molecule in ER-related apoptosis. The purpose of this study is to evaluate the protective activity and possible mechanism of resveratrol (ResV) against ethanol (EtOH)-induced apoptosis in human hepatocyte Chang cell line. METHODS: The human hepatocyte Chang cell line was used to test the hypothesis that ResV may alleviate the liver cell apoptosis induced by EtOH. ER stress-inducible proteins and silent mating type information regulation 2 homolog 1 (SIRT1) were assayed by Western blot. Cell viability was studied by MTT assay and apoptosis was measured by Annexin-V and propidium iodide assay. Caspase-12 activation was examined by immunofluorescence staining. Alcohol dehydrogenase-2 (ADH-2) and aldehyde dehydrogenase-2 (ALDH-2) were measured by polymerase chain reaction amplified product length polymorphism. Phosphodiesterase (PDE) activity was assayed in cell lysates using a cyclic nucleotide PDE assay. RESULTS: EtOH exposure significantly increased the expression of ER stress markers and activated signaling pathways associated with ER stress. These include GRP78, p-IRE1α, p-eIF2α, p-PERK, ATF4 as well as cleaved caspase-3/12, CHOP/GADD153, and Bax in human hepatocyte Chang cell line. The expression of these proteins were significantly down-regulated by ResV (10 µM) in a SIRT1-dependent manner. ResV can inhibit EtOH-, tunicamycin-, thapsigargin-induced caspase-12 activation. ADH-2 and ALDH-2 activities are lower in this cell line. PDE activity increased by EtOH was inhibited by ResV (10 µM). CONCLUSIONS: The results indicate that (i) EtOH-induced activation of caspase-12 could be one of the underlying mechanisms of hepatocyte apoptosis; (ii) EtOH-induced cell apoptosis was alleviated via ResV (10 µM) by inhibiting ER stress and caspase-12 activation in a SIRT1-dependent manner; and (iii) SIRT1 activated indirectly by ResV (10 µM) attenuates EtOH-induced hepatocyte apoptosis partly through inhibiting PDE activity.

Thiamine deficiency induces endoplasmic reticulum stress in neurons.

Thiamine (vitamin B1) deficiency (TD) causes region selective neuronal loss in the brain; it has been used to model neurodegeneration that accompanies mild impairment of oxidative metabolism. The mechanisms for TD-induced neurodegeneration remain incompletely elucidated. Inhibition of protein glycosylation, perturbation of calcium homeostasis and reduction of disulfide bonds provoke the accumulation of unfolded proteins in the endoplasmic reticulum (ER), and cause ER stress. Recently, ER stress has been implicated in a number of neurodegenerative models. We demonstrated here that TD up-regulated several markers of ER stress, such as glucose-regulated protein (GRP) 78, growth arrest and DNA-damage inducible protein or C/EBP-homologus protein (GADD153/Chop), phosphorylation of eIF2alpha and cleavage of caspase-12 in the cerebellum and the thalamus of mice. Furthermore, ultrastructural analysis by electron microscopic study revealed an abnormality in ER structure. To establish an in vitro model of TD in neurons, we treated cultured cerebellar granule neurons (CGNs) with amprolium, a potent inhibitor of thiamine transport. Exposure to amprolium caused apoptosis and the generation of reactive oxygen species in CGNs. Similar to the observation in vivo, TD up-regulated markers for ER stress. Treatment of a selective inhibitor of caspase-12 significantly alleviated amprolium-induced death of CGNs. Thus, ER stress may play a role in TD-induced brain damage.

Measurements of the cross section for e(+)e(-) --> hadrons at center-of-mass energies from 2 to 5 GeV.

We report values of R = sigma(e(+)e(-)-->hadrons)/sigma(e(+)e(-)-->mu(+)mu(-)) for 85 center-of-mass energies between 2 and 5 GeV measured with the upgraded Beijing Spectrometer at the Beijing Electron-Positron Collider.

Estrogen modulation of the cyclic AMP response element-binding protein pathway. Effects of long-term and acute treatments.

Actions of estrogen include mechanisms leading to alterations in gene transcription that may be independent of nuclear estrogen receptors, as well as those involving direct action of the estrogen receptor on the genome. Also, the influence of estrogen in the brain appears to extend well beyond areas associated with reproduction and may include forebrain areas linked to affective and cognitive behaviors. We investigated the effects of acute and long-term estradiol benzoate (E2) treatment on total and phosphorylated cyclic AMP responsive element-binding (CREB) protein levels and on cyclic AMP response element (CRE)-DNA binding in forebrain areas of ovariectomized (OVX) rats. Long-term E2 treatment increased CRE-DNA binding in the amygdala but not in hippocampus, frontal cortex, or cerebellum. The increase in CRE-DNA binding in the amygdala was associated with increased levels of total and phosphorylated CREB (pCREB) protein during protracted E2 exposure. To localize the estrogenic effect in the amygdala and determine if an effect in one hippocampal region was masked by a lack of effect in another subregion, we performed immunolabeling of pCREB in brain structures of chronically treated OVX animals with or without E2. This treatment resulted in a significant increase in relative total immunolabeled nuclei in the anteroventral subdivision of the medial amygdala. In the hippocampus, a significant increase in relative total immunolabeled nuclei was seen in the CA1 and CA3 regions, but not in the dentate gyrus or hilus of the dentate gyrus. Acute E2 treatment resulted in increased CRE-DNA binding in the frontal cortex but not in amygdala, hippocampus, or cerebellum. However, no changes in levels of total CREB or pCREB protein were observed in the frontal cortex under E2 treatment. No changes were observed either in basal or cAMP-stimulated protein kinase A (PKA) activity or in PKA-alpha catalytic subunit immunoreactivity in the amygdala or the frontal cortex. Our study indicates that both long-term and acute treatments with estrogens influence the function of CREB in specific brain structures.

Apolipoprotein E is a genetic risk factor for fetal iodine deficiency disorder in China.

Fetal iodine deficiency disorder (FIDD) is the principal form of endemic cretinism, and the most common cause of preventable mental deficiency in the world. However not everyone at risk develops FIDD and familial aggregation is common. This suggests that genetic factors may also be involved. The Apolipoprotein E (APOE) gene encodes for a lipoprotein that possesses a thyroid hormone binding domain, and APOE genotype may affect the efficiency with which thyroid hormone influences neuronal cell growth during the first and second trimesters of fetal development. We have compared ApoE genotypes in 91 FIDD cases with 154 local control subjects, recruited from three iodine deficiency areas in central China. We have also genotyped 42 FIDD family cases and 158 normal individuals from the families of local controls, and 375 population controls from Shanghai. APOE epsilon4 genotypes were significantly enriched in FIDD probands from each of the three iodine deficiency areas; the epsilon4 allele frequency was 16% vs 6% in controls. The same effect was also observed when we compared FIDD family cases with controls and control families. Our data suggest that in iodine-deficient areas, the APOE epsilon4 allele is a genetic risk factor for FIDD. The phenomenon may affect population selection and contribute to the low frequency of the epsilon4 allele in Chinese compared to Caucasian populations.

[The neuroethological basis of learning and memory decline in aged rats].

The spatial reference and working memory abilities, GFAP-positive astrocytes and GABAergic interneurons were studied quantitatively in young, aged memory-unimpaired and aged memory-impaired rats according to their learning and memory abilities in the Morris water maze. The results showed that the prominent behavioural features of the aged memory-impaired rat were a change in the searching pattern, a decrease in the spatial reference memory, no significant decrease in the spatial working memory was observed. The decrease of GABAergic neurons, and the increase of GFAP-positive astrocytes in the dentate gyrus of the aged memory-impaired rat were more obvious than the other two groups. The main abnormalities of morphologic indexes were closely correlated with the decline of learning and memory in the aged rat.