Trehalose Abstracts 1

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Trehalose prevents adipocyte hypertrophy and mitigates insulin resistance in mice with established obesity

         (Arai, Miyake et al. 2013)  Download

Our group recently demonstrated that simultaneous administration of trehalose with a high-fat diet (HFD) suppresses adipocyte hypertrophy and mitigates insulin resistance in mice. For the present study, we hypothesized that similar effects of trehalose would be observed in mice with previously-established obesity. Obese mice were fed a HFD and drinking water containing 0.3 or 2.5% (weight/volume) trehalose or distilled water (DW) ad libitum for 8 wk. After 7 wk intake of a HFD and trehalose, fasting serum insulin levels and homeostasis model assessment-insulin resistance (HOMA-IR) in the 0.3% Tre/HFD group were significantly lower than those in the DW/HFD group (p<0.05). After 8 wk of treatment, mesenteric adipocytes in the 0.3% Tre/HFD group showed significantly less hypertrophy than those in the DW/HFD group. Mechanistic analysis indicated that levels of high molecular weight (HMW) adiponectin in the serum of the 0.3% Tre/HFD group were significantly higher than those in the DW/HFD group. The expression levels of insulin receptor substrate-1 (IRS-1) and insulin receptor substrate-2 (IRS-2) messenger RNA (mRNA) in muscle were also significantly increased by trehalose intake. Our data therefore suggest that administration of trehalose to obese mice mitigates insulin resistance by suppressing adipocyte hypertrophy and increasing serum HMW adiponectin, resulting in upregulation of IRS-1, and IRS-2 expression in muscle. These results further suggest that trehalose is a functional saccharide that may be used to prevent the progression of insulin resistance.


Fructose, trehalose and sorbitol malabsorption

         (Montalto, Gallo et al. 2013) Download

Carbohydrate malabsorption is a frequent clinical condition, often associated with abdominal symptoms. Although lactose represents the most commonly malabsorbed sugar, also other carbohydrates, such as fructose, trehalose and sorbitol may be incorrectly absorbed in the small intestine. Fructose malabsorption seems more common in patients with functional bowel disease, even if randomized and controlled studies on these topic were few and on small samples. Interpretation of breath hydrogen testing is difficult. In particular, neither studies comparing this test with a gold standard, nor validated doses and concentrations to be used, are available. Trehalose malabsoption due to trehalase deficiency represents a very rare condition and available studies do not support its relevance in clinical practice. Sorbitol absorption is dose and concentration related, and depends on the entity of intestinal absorption surface. Nevertheless, the finding of its malabsorption is not expression of a specific cause of intestinal bowel damage. From available data, it is not possible to draw definite conclusions about clinical relevance of fructose, trehalose and sorbitol malabsorption, as well as, about diagnostic accuracy of commonly used tests to detect all these conditions. On the other hand, in patients who refer abdominal discomfort after ingestion of different carbohydrate-containing foods, a small intestinal bacterial overgrowth, should be promptly considered. This is because the large amount of intestinal bacteria may unspecifically ferment sugars, causing an abnormal H2 production and consequently a misleading diagnosis of sugar malabsorption.

Trehalose, a novel mTOR-independent autophagy enhancer, accelerates the clearance of mutant huntingtin and alpha-synuclein

         (Sarkar, Davies et al. 2007) Download

Trehalose, a disaccharide present in many non-mammalian species, protects cells against various environmental stresses. Whereas some of the protective effects may be explained by its chemical chaperone properties, its actions are largely unknown. Here we report a novel function of trehalose as an mTOR-independent autophagy activator. Trehalose-induced autophagy enhanced the clearance of autophagy substrates like mutant huntingtin and the A30P and A53T mutants of alpha-synuclein, associated with Huntington disease (HD) and Parkinson disease (PD), respectively. Furthermore, trehalose and mTOR inhibition by rapamycin together exerted an additive effect on the clearance of these aggregate-prone proteins because of increased autophagic activity. By inducing autophagy, we showed that trehalose also protects cells against subsequent pro-apoptotic insults via the mitochondrial pathway. The dual protective properties of trehalose (as an inducer of autophagy and chemical chaperone) and the combinatorial strategy with rapamycin may be relevant to the treatment of HD and related diseases, where the mutant proteins are autophagy substrates.

Trehalose alleviates polyglutamine-mediated pathology in a mouse model of Huntington disease

         (Tanaka, Machida et al. 2004) Download

Inhibition of polyglutamine-induced protein aggregation could provide treatment options for polyglutamine diseases such as Huntington disease. Here we showed through in vitro screening studies that various disaccharides can inhibit polyglutamine-mediated protein aggregation. We also found that various disaccharides reduced polyglutamine aggregates and increased survival in a cellular model of Huntington disease. Oral administration of trehalose, the most effective of these disaccharides, decreased polyglutamine aggregates in cerebrum and liver, improved motor dysfunction and extended lifespan in a transgenic mouse model of Huntington disease. We suggest that these beneficial effects are the result of trehalose binding to expanded polyglutamines and stabilizing the partially unfolded polyglutamine-containing protein. Lack of toxicity and high solubility, coupled with efficacy upon oral administration, make trehalose promising as a therapeutic drug or lead compound for the treatment of polyglutamine diseases. The saccharide-polyglutamine interaction identified here thus provides a new therapeutic strategy for polyglutamine diseases.

Trehalose prevents neural tube defects by correcting maternal diabetes-suppressed autophagy and neurogenesis

         (Xu, Li et al. 2013) Download

Preexisting maternal diabetes increases the risk of neural tube defects (NTDs). The mechanism underlying maternal diabetes-induced NTDs is not totally defined, and its prevention remains a challenge. Autophagy, an intracellular process to degrade dysfunction protein and damaged cellular organelles, regulates cell proliferation, differentiation, and apoptosis. Because autophagy impairment causes NTDs reminiscent of those observed in diabetic pregnancies, we hypothesize that maternal diabetes-induced autophagy impairment causes NTD formation by disrupting cellular homeostasis, leading to endoplasmic reticulum (ER) stress and apoptosis, and that restoration of autophagy by trehalose, a natural disaccharide, prevents diabetes-induced NTDs. Embryos from nondiabetic and type 1 diabetic mice fed with or without 2 or 5% trehalose water were used to assess markers of autophagy, ER stress, and neurogenesis, numbers of autophagosomes, gene expression that regulates autophagy, NTD rates, indices of mitochondrial dysfunction, and neuroepithelial cell apoptosis. Maternal diabetes suppressed autophagy by significantly reducing LC3-II expression, autophagosome numbers, and GFP-LC3 punctate foci in neuroepithelial cells and by altering autophagy-related gene expression. Maternal diabetes delayed neurogenesis by blocking Sox1 neural progenitor differentiation. Trehalose treatment reversed autophagy impairment and prevented NTDs in diabetic pregnancies. Trehalose resolved homeostatic imbalance by correcting mitochondrial defects, dysfunctional proteins, ER stress, apoptosis, and delayed neurogenesis in the neural tubes exposed to hyperglycemia. Our study demonstrates for the first time that maternal diabetes suppresses autophagy in neuroepithelial cells of the developing neural tube, leading to NTD formation, and provides evidence for the potential efficacy of trehalose as an intervention against hyperglycemia-induced NTDs.

Trehalose inhibits fibrillation of A53T mutant alpha-synuclein and disaggregates existing fibrils

         (Yu, Jiang et al. 2012) Download

The aggregation of alpha-synuclein (AS) is pivotally implicated in the development of Parkinson's disease (PD), inhibiting this process might be effective in treating PD. Here, by using circular dichroism spectroscopy, thioflavin T fluorescence, and atomic force microscopy, we found that trehalose at low concentration disaggregates preformed A53T AS protofibrils and fibrils into small aggregates or even random coil structure, while trehalose at high concentration slows down the structural transition into beta-sheet structure and completely prevents the formation of mature A53T AS fibrils. Further work in vivo will be needed to evaluate its potential as a novel strategy for treating PD.


References

Arai, C., M. Miyake, et al. (2013). "Trehalose prevents adipocyte hypertrophy and mitigates insulin resistance in mice with established obesity." J Nutr Sci Vitaminol (Tokyo) 59(5): 393-401. [PMID: 24418873]

Montalto, M., A. Gallo, et al. (2013). "Fructose, trehalose and sorbitol malabsorption." Eur Rev Med Pharmacol Sci 17 Suppl 2: 26-9. [PMID: 24443064]

Sarkar, S., J. E. Davies, et al. (2007). "Trehalose, a novel mTOR-independent autophagy enhancer, accelerates the clearance of mutant huntingtin and alpha-synuclein." J Biol Chem 282(8): 5641-52. [PMID: 17182613]

Tanaka, M., Y. Machida, et al. (2004). "Trehalose alleviates polyglutamine-mediated pathology in a mouse model of Huntington disease." Nat Med 10(2): 148-54. [PMID: 14730359]

Xu, C., X. Li, et al. (2013). "Trehalose prevents neural tube defects by correcting maternal diabetes-suppressed autophagy and neurogenesis." Am J Physiol Endocrinol Metab 305(5): E667-78. [PMID: 23880312]

Yu, W. B., T. Jiang, et al. (2012). "Trehalose inhibits fibrillation of A53T mutant alpha-synuclein and disaggregates existing fibrils." Arch Biochem Biophys 523(2): 144-50. [PMID: 22575388]