乳鐵蛋白衍生胜肽調節黑色素生成之篩選與功能探討

Abstract

黑色素在皮膚與毛髮中扮演著抵禦紫外線 (UV) 傷害及維持外觀的重要角色。黑色素生成過程受到細胞內複雜訊息路徑的調控，並依賴黑色素體的成熟與酪氨酸酶等關鍵酵素的活化。當機制發生失調時，便會引發黑色素缺失疾病，如白斑症與早發性灰白髮，仍是目前臨床皮膚科學面臨的重要挑戰。由於現有臨床促黑治療常面臨療效有限與高復發率的瓶頸，且傳統方式如類固醇治療亦導致皮膚萎縮、微血管擴張、甚至誘發毛囊炎。近年來，乳鐵蛋白展現出豐富的生物活性，其衍生胜肽更因具備高專一性與優異的生物相容性，成為新興藥物開發的熱點；然而，其在調控黑色素生成中的作用與機制尚不完全清楚。在本研究中，我們透過篩選乳鐵蛋白衍生胜肽庫，發現 bLF1 (CVRRAFVLEC) 能顯著促進 B16F10 細胞的黑色素合成，且在長達 72 小時與高達 200 µg/mL 的高濃度處理下，依然維持極佳的細胞存活率。在分子機制上，bLF1在不影響細胞活性的情況下，透過標靶活化 PKA/CREB 訊息傳遞軸驅動下游酵素表現，上調了MITF，TYR，TRP1 等黑色素促進相關的蛋白表現量。此外，形成分子內雙硫鍵的 10-mer 環狀結構，能顯著強化其促黑能力；免疫熒光染色追蹤也發現，bLF1 能透過內吞作用進入並穩定累積於晚期內體中以發揮效應。 綜上所述，本研究確立了 bLF1 為一款高效且無毒性的多功能候選胜肽，有望為未來黑色素缺失疾病提供具臨床價值的潛力藥物。

Melanin plays a crucial role in the skin and hair by protecting against ultraviolet (UV) damage and maintaining physical appearance. Melanogenesis is regulated by different intracellular signaling pathways and relies on melanosome maturation and the activation of key enzymes. Dysregulation of this mechanism leads to hypopigmentation disorders, such as vitiligo and premature hair graying, which remain significant challenges in clinical dermatology. Current clinical therapies are often hindered by limited efficacy and high recurrence rates. Furthermore, traditional treatments like corticosteroids can cause adverse effects, including skin atrophy, telangiectasia, and even folliculitis. Recently, lactoferrin has exhibited diverse bioactivities, and its derived peptides have emerged for novel drug development due to their high specificity and superior biocompatibility; however, their roles and mechanisms in regulating melanogenesis remain unclear. In this study, by screening a library of lactoferrin-derived peptides, we discovered that bLF1 (CVRRAFVLEC) significantly promotes melanin synthesis in B16F10 cells while maintaining exceptional cell viability, even under long-term (72 hours) and high-concentration (200 µg/mL) treatments. The underlying mechanism is that bLF1 activates the PKA/CREB signaling axis to drive downstream enzyme expression, thereby upregulating key melanogenic proteins such as MITF, TYR, and TRP1. Furthermore, the 10-mer cyclic structure formed by an intramolecular disulfide bond significantly enhances its melanogenic capacity. Immunofluorescence tracking also revealed that bLF1 is internalized via endocytosis and stably accumulates in late endosomes to exert its downstream effects. In conclusion, this study establishes bLF1 as a highly efficient and non-toxic multifunctional candidate peptide, offering a promising therapeutic option with significant clinical value for the future treatment of hypopigmentation disorders.