The follicle is the functional unit of the ovary, which is composed of three types of cells: oocytes, granulosa cells, and theca cells. Ovarian follicle development and the subsequent ovulation process are coordinated by highly complex interplay between endocrine, paracrine, and autocrine signals, which coordinate steroidogenesis and gametogenesis. Follicle development is regulated mainly by three organs, the hypothalamus, anterior pituitary, and gonad, which make up the hypothalamic-pituitary-gonadal axis. Steroid hormones and their receptors play pivotal roles in follicle development and participate in a series of classical signaling pathways. In this review, we summarize and compare the role of classical signaling pathways, such as the WNT, insulin, Notch, and Hedgehog pathways, in ovarian follicle development and the underlying regulatory mechanism. We have also found that these four signaling pathways all interact with FOXO3, a transcription factor that is widely known to be under control of the PI3K/AKT signaling pathway and has been implicated as a major signaling pathway in the regulation of dormancy and initial follicular activation in the ovary. Although some of these interactions with FOXO3 have not been verified in ovarian follicle cells, there is a high possibility that FOXO3 plays a core role in follicular development and is regulated by classical signaling pathways. In this review, we present these signaling pathways from a comprehensive perspective to obtain a better understanding of the follicular development process.

Objective: Alzheimer's Disease (AD) is well characterized by the accumulated Aβ plaque in hippocampus and cerebral cortex concomitant with markedly reduced study and learning ability. Trehalose, a natural disaccharide, has been shown to have neural protective properties and exhibited therapeutic effects in animal models of several neural degenerative disorders. However, the effect of trehalose on AD pathology remains largely unknown. Methods: In this study, we evaluated the effects of trehalose in APP/PS1 transgenic mice through behaviour tests and biochemical analyses. Key findings: We found that the impaired cognitive and learning ability was improved and Aβ deposit in hippocampus was reduced. Conclusions: These results suggested that trehalose could be a potential therapeutic drug for the treatment of AD.

Calorie restriction (CR) extends lifespan from yeast to mammals. SIRT6 is a member of the sirtuin family of NAD⁺-dependent histone deacetylases, which is responsible for mediating the effects of CR. The transcription factor NF-κB, which is involved in inflammation and aging, has been shown to be regulated by SIRT6. Here we describe the crucial role of SIRT6 in aging and inflammation. We show that CR had improved renal insufficiency and enhanced SIRT6 expression after 6-month treatment in aged mice. Culture cells in low glucose (LG) conditions also showed resistance to cell senescence and enhanced SIRT6 expression compared to normal glucose (NG) group, showing beneficial effects of the CR-mimic cultural conditions. Moreover, SIRT6 overexpression is sufficient to delay the replicative senescence of WI38 by attenuating NF-κB signaling, while SIRT6 knockdown results in accelerated cell senescence and overactive NF-κB signaling. These findings confirm the key status of CR and disclose the critical role of SIRT6 on aging and inflammation.