Is vitiligo associated with systemic aquaporin-3 deficiency?

Aquaporins: A new target for traditional Chinese medicine in the treatment of digestive system diseases

Aquaporins (AQPs) are a family of transmembrane proteins expressed in various organ systems. Many studies have shown that the abnormal expression of AQPs is associated with gastrointestinal, skin, liver, kidneys, edema, cancer, and other diseases. The majority of AQPs are expressed in the digestive system and have important implications for the physiopathology of the gastrointestinal tract as well as other tissues and organs. AQP regulators can prevent and treat most gastrointestinal-related diseases, such as colorectal cancer, gastric ulcer, and gastric cancer. Although recent studies have proposed clinically relevant AQP-targeted therapies, such as the development of AQP inhibitors, clinical trials are still lacking and there are many difficulties. Traditional Chinese medicine (TCM) has been used in China for thousands of years to prevent, treat and diagnose diseases, and is under the guidance of Chinese medicine (CM) theory. Herein, we review the latest research on the regulation of AQPs by TCMs and their active components, including Rhei Radix et Rhizoma, Atractylodis macrocephalae Rhizoma, Salviae miltiorrhizae Radix et Rhizoma, Poria, Astragali radix, and another 26 TCMs, as well as active components, which include the active components include anthraquinones, saponins, polysaccharides, and flavonoid glycosides. Through our review and discussion of numerous studies, we attempt to explore the regulatory effects of TCMs and their active components on AQP expression in the corresponding parts of the body in terms of the Triple Energizer concept in Chinese medicine defined as "upper energizer, middle energizer, and lower energizer,"so as to offer unique opportunities for the development of AQP-related therapeutic drugs for digestive system diseases.

Poria cocos Extract from Mushrooms Stimulates Aquaporin-3 via the PI3K/Akt/mTOR Signaling Pathway

Background

Poria cocos (PC), a fungus, has been used for more than 2000 years as a food and medicine in China. PC and its components have various pharmacological effects on the skin, including immunomodulatory activities, barrier function improvement, and anti-tumor effects. However, the effect of PC in aquaporin-3 (AQP3) expression, which is essential for epidermal water permeability barrier maintenance, was not reported.

Methods

This study examined the mechanism through which the ethanol extract of the sclerotium of PC (EPC) promoted the expression of AQP3 in cultured human keratinocytes. Western blotting was used to investigate the expression of AQPs and the activation of phosphoinositide 3-kinase (PI3K)/Akt-related signaling molecules in HaCaT cells. Cells were treated with inhibitors of PI3K/Akt and mechanistic target of rapamycin (mTOR) prior to EPC treatment.

Results

EPC promoted the expression of AQP3 in HaCaT cells without affecting AQP1 and AQP2 expression. Phosphorylated Akt levels were increased by EPC treatment, and the inhibition of PI3K by LY2940002 resulted in a reduction in EPC-induced AQP3 expression. Furthermore, EPC stimulated the phosphorylation of p70S6K and Akt^Ser473, which are downstream targets of mTORC1 and mTORC2, respectively. The mTOR complex inhibitors, rapamycin and Torin 1, partially reduced EPC-induced AQP3 expression.

Conclusion

These results suggest that EPC increased expression of AQP3, which is important for skin moisturization, by activating the PI3K/Akt/mTOR signaling pathway in human keratinocytes.