Alzheimer’s disease (AD) is an age-related neurodegenerative disorder and the most common cause of dementia. Various pathogenic mechanisms have been proposed to contribute to disease progression, and recent research provided evidence linking dysregulated circadian rhythms/sleep and energy metabolism with AD. Previously, we found that the natural compound Nobiletin (NOB) can directly activate circadian cellular oscillators to promote metabolic health in disease models and healthy aging in naturally aged mice. In the current study, using the amyloid-β AD model APP/PS1, we investigated circadian, metabolic and amyloid characteristics of female mice and the effects of NOB. Female APP/PS1 mice showed reduced sleep bout duration, and NOB treatment exhibited a trend to improve it. While glucose tolerance was unchanged, female APP/PS1 mice displayed exaggerated oxygen consumption and CO2 production, which was mitigated by NOB. Likewise, cold tolerance in APP/PS1 was impaired relative to WT, and interestingly was markedly enhanced in NOB-treated APP/PS1 mice. Although circadian behavioral rhythms were largely unchanged, real-time qPCR analysis revealed altered expression of several core clock genes by NOB in the cerebral cortex, notably Bmal1, Npas2, and Rora. Moreover, NOB was also able to activate various clock-controlled metabolic genes involved in insulin signaling and mitochondrial function, including Igf1, Glut1, Insr, Irs1, Ucp2, and Ucp4. Finally, we observed that NOB attenuated the expression of several AD related genes including App, Bace1, and ApoE, reduced APP protein levels, and strongly ameliorated Aβ pathology in the cortex. Collectively, these results reveal novel genotype differences and importantly beneficial effects of a natural clock-enhancing compound in biological rhythms and related pathophysiology, suggesting the circadian clock as a modifiable target for AD.

Lee J, et al. Nutr Res Pract. 2020 Oct;14(5):438-452. https://doi.org/10.4162/nrp.2020.14.5.438

Type 2 diabetes is a major public health concern worldwide. Xylobiose (XB) consists of two molecules of d-xylose and is a major disaccharide in xylooligosaccharides that are used as prebiotics. We hypothesized that XB could regulate diabetes-related metabolic and genetic changes via microRNA expression in db/db mice. For six weeks, C57BL/KsJ-db/db mice received 5% XB as part of the total sucrose content of their diet. XB supplementation improved glucose tolerance with reduced levels of OGTT AUC, fasting blood glucose, HbA1c, insulin, and HOMA-IR. Furthermore, XB supplementation decreased the levels of total triglycerides, total cholesterol, and LDL-C. The expression levels of miR-122a and miR-33a were higher and lower in the XB group, respectively. In the liver, expressions of the lipogenic genes, including, fatty acid synthase (FAS), peroxisome proliferator activated receptor γ (PPARγ), sterol regulatory element-binding protein-1C (SREBP-1C), sterol regulatory element-binding protein-2 (SREBP-2), acetyl-CoA carboxylase (ACC), HMG-CoA reductase (HMGCR), ATP-binding cassette transporter G5/G8 (ABCG5/8), cholesterol 7 alpha-hydroxylase (CYP7A1), and sterol 12-alpha-hydroxylase (CYP8B1), as well as oxidative stress markers, including superoxide dismutase 1 (SOD1), superoxide dismutase 2 (SOD2), glutathione peroxidase (GPX), and catalase, were also regulated by XB supplementation. XB supplementation inhibited the mRNA expressions levels of the pro-inflammatory cytokines, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, interleukin (IL)-6, and monocyte chemoattractant protein (MCP)-1, as well as phosphorylation of c-Jun N-terminal kinase/stress activated protein kinase (JNK/SAPK), p38 mitogen-activated protein kinases (MAPK), and extracellular signal-regulated kinases 1/2 (ERK1/2). These data demonstrate that XB exhibits anti-diabetic, hypolipogenic, and anti-inflammatory effects via regulation of the miR-122a/33a axis in db/db mice.

Jeon HJ, et al. Nutr Res Pract. 2018 Apr;12(2):101-109. https://doi.org/10.4162/nrp.2018.12.2.101

Physical inactivity and high-fat diet, especially high saturated fat containing diet are established risk factors for breast cancer that are amenable to intervention. High-fat diet has been shown to induce tumor growth and metastasis by alteration of inflammation but steady exercise has anti-tumorigenic effects. However, the mechanisms underlying the effects of physical activity on high-fat diet stimulated breast cancer initiation and progression are currently unclear. In this study, we examined how the intensity of physical activity influences high fat diet-stimulated breast cancer latency and progression outcomes, and the possible mechanisms behind these effects. Five-week-old female Balb/c mice were fed either a control diet or a high-fat diet for 8 weeks, and then 4T1 mouse mammary tumor cells were inoculated into the mammary fat pads. Exercise training occurred before tumor cell injection, and tumor latency and tumor volume were measured. Mice with a high-fat diet and low-intensity exercise (HFLE) had a longer tumor latency period, slower tumor growth, and smaller tumor volume in the final tumor assessment compared with the control, high-fat diet control (HFDC), and high-fat diet with moderate-intensity exercise (HFME) groups. Steady low- and moderate-intensity exercise had no effect on cell proliferation but induced apoptosis by activating caspase-3 through the alteration of Bcl-2, Bcl-xL, and Bax expression. Furthermore, steady exercise reduced M2 macrophage polarization in breast tumor tissue, which has been linked to tumor growth. The myokine, myostatin, reduced M2 macrophage polarization through the inhibition of the JAK-STAT signaling pathway. These results suggest that steady low-intensity exercise could delay breast cancer initiation and growth and reduce tumor volume through the induction of tumor cell apoptosis and the suppression of M2 macrophage polarization.

Phyllodulcin is a natural sweetener found in Hydrangea macrophylla var. thunbergii. This study investigated whether phyllodulcin could improve metabolic abnormalities in high-fat diet (HFD)-induced obese mice. Animals were fed a 60% HFD for 6 weeks to induce obesity, followed by 7 weeks of supplementation with phyllodulcin (20 or 40 mg/kg body weight (b.w.)/day). Stevioside (40 mg/kg b.w./day) was used as a positive control. Phyllodulcin supplementation reduced subcutaneous fat mass, levels of plasma lipids, triglycerides, total cholesterol, and low-density lipoprotein cholesterol and improved the levels of leptin, adiponectin, and fasting blood glucose. In subcutaneous fat tissues, supplementation with stevioside or phyllodulcin significantly decreased mRNA expression of lipogenesis-related genes, including CCAAT/enhancer-binding protein α (C/EBPα), peroxisome proliferator activated receptor γ (PPARγ), and sterol regulatory element-binding protein-1C (SREBP-1c) compared to the high-fat group. Phyllodulcin supplementation significantly increased the expression of fat browning-related genes, including PR domain containing 16 (Prdm16), uncoupling protein 1 (UCP1), and peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α), compared to the high-fat group. Hypothalamic brain-derived neurotrophic factor-tropomyosin receptor kinase B (BDNF-TrkB) signaling was upregulated by phyllodulcin supplementation. In conclusion, phyllodulcin is a potential sweetener that could be used to combat obesity by regulating levels of leptin, fat browning-related genes, and hypothalamic BDNF-TrkB signaling.