Glucose Exerts an Anti-Melanogenic Effect by Indirect Inactivation of Tyrosinase in Melanocytes and a Human Skin Equivalent

Abstract

Sugars are ubiquitous in organisms and well-known cosmetic ingredients for moisturizing skin with minimal side-effects. Glucose, a simple sugar used as an energy source by living cells, is often used in skin care products. Several reports have demonstrated that sugar and sugar-related compounds have anti-melanogenic effects on melanocytes. However, the underlying molecular mechanism by which glucose inhibits melanin synthesis is unknown, even though glucose is used as a whitening as well as moisturizing ingredient in cosmetics. Herein, we found that glucose significantly reduced the melanin content of α-melanocyte-stimulating hormone (MSH)-stimulated B16 cells and darkly pigmented normal human melanocytes with no signs of cytotoxicity. Furthermore, topical treatment of glucose clearly demonstrated its whitening efficacy through photography, Fontana-Masson (F&M) staining, and multi-photon microscopy in a pigmented 3D human skin model, MelanoDerm. However, glucose did not alter the gene expression or protein levels of major melanogenic proteins in melanocytes. While glucose potently decreased intracellular tyrosinase activity in melanocytes, it did not reduce mushroom tyrosinase activity in a cell-free experimental system. However, glucose was metabolized into lactic acid, which can powerfully suppress tyrosinase activity. Thus, we concluded that glucose indirectly inhibits tyrosinase activity through conversion into lactic acid, explaining its anti-melanogenic effects in melanocytes.

The role of Smad4 in the regulation of insulin resistance, inflammation and cell proliferation in HTR8‐Svneo cells

“…The glucose uptake has been acknowledged as a major source of energy for cell survival, 33 and the effective insulin secretion and function are reported to play an essential role in blood glucose homeostasis 34 . Significantly impaired glucose consumption was found in the cellular model of IR according to our study, further indicating the relation between defective glucose homeostasis and insulin resistance.…”

Human Melanocyte-Derived Spheroids: A Precise Test System for Drug Screening and a Multicellular Unit for Tissue Engineering

“…The expanding ozone holes in the atmosphere lead to the growing danger of UV skin damage, making the pharmaceutical industry increase the production of new types of sun protection (Smit et al, 2009;Zastrow et al, 2017), which requires the new systems for testing them in vitro. At present, the mainly used testsystems are primary cultures of melanocytes and keratinocytes (Lei et al, 2002;Lee et al, 2020), melanoma cell lines (Kim et al, 2017;Lee et al, 2020), the commercial tissue equivalents (EpiSkin TM , MelanoDerm TM , and others) (Costin and Raabe, 2013;Kim et al, 2017;Meena and Mohandass, 2019;Lee et al, 2020), and tissue equivalents obtained from cells with induced pluripotency (iPSC) (Gledhill et al, 2015). These approaches have some limitations, including non-physiological conditions (for 2D cultures), difficulties in analysis, and expensiveness (for commercial tissue equivalents).…”

TCF19 and p53 regulate transcription of TIGAR and SCO2 in HCC for mitochondrial energy metabolism and stress adaptation

“…Glycolytic end product pyruvate converted to lactate was measured by the kit‐based method (Abcam, Cat no. ab65331) following the protocol provided by the manufacturer followed in previous studies 54,55 . In brief, around 2X10 6 cells were cultured and harvested.…”

“…ab65331) following the protocol provided by the manufacturer followed in previous studies. 54,55 In brief, around 2X10 6 cells were cultured and harvested. After ice-cold PBS wash, they were resuspended in lactate assay buffer and homogenized well immediately.…”