Protoporphyrin IX is an important porphyrin compound in the heme biosynthetic pathway and is commonly used in photodynamic therapy[1]. Protoporphyrin IX binds with iron ions to form ferrous protoporphyrin, which then combines with globin to generate hemoglobin, thereby maintaining oxygen transport and cellular respiration functions[2]. In photodynamic therapy, Protoporphyrin IX primarily serves as a photosensitizer, capable of absorbing specific wavelengths of light and generating reactive oxygen species[3]. In addition, the fluorescence imaging of Protoporphyrin IX (excitation wavelength 488nm, emission wavelength 620nm) can also be utilized to improve surgical outcomes[4].
In vitro, Protoporphyrin IX (10-30μM) treatment of SK-MEL-2 melanoma cells and human normal melanocytes (HNM) for 48 hours significantly promotes melanin synthesis, increases tyrosinase activity, and upregulates the expression levels of MITF, tyrosinase, TRP-1, and TRP-2, while also promoting dendrite formation and melanosome transport in melanocytes[5]. The novel conjugate CH−PPIX (0.005%, w/v) formed by Protoporphyrin IX and chitosan oligosaccharides (CH) exhibits 100% inhibitory efficiency against Penicillium digitatum under visible light irradiation. This conjugate exerts antifungal effects through the generation of singlet oxygen, leading to spore uptake and photoinduced membrane damage[6].
In vivo, Protoporphyrin IX (3.5mg/kg) was administered to mice via a single intraperitoneal injection or daily injections for 5 consecutive days. Two hours after a single dose, the accumulation of porphyrins in the mouse liver peaked. After five doses, Protoporphyrin IX accumulation induced oxidative stress, causing severe liver damage and impairing the antioxidant system[7]. Protoporphyrin IX-modified oxidized mesoporous carbon nanospheres (1mg/kg) were injected into APP/PS1 transgenic mice via the tail vein and activated by focused ultrasound. These nanospheres could effectively cross the blood-brain barrier (BBB), significantly inhibit Tau protein phosphorylation and β-amyloid (Aβ) aggregation, and improve cognitive function in mice[8].
References:
[1] Juzenas P, Juzeniene A, Stakland S, et al. Photosensitizing effect of protoporphyrin IX in pigmented melanoma of mice. Biochem Biophys Res Commun. 2002 Sep 27;297(3):468-72.
[2] Kiening M, Lange N. A Recap of Heme Metabolism towards Understanding Protoporphyrin IX Selectivity in Cancer Cells. Int J Mol Sci. 2022 Jul 19;23(14):7974.
[3] Hussain Z, Qi Q, Zhu J, Anderson KE, et al. Protoporphyrin IX-induced phototoxicity: Mechanisms and therapeutics. Pharmacol Ther. 2023 Aug;248:108487.
[4] Valdes PA, Millesi M, Widhalm G, et al. 5-aminolevulinic acid induced protoporphyrin IX (ALA-PpIX) fluorescence guidance in meningioma surgery. J Neurooncol. 2019 Feb;141(3):555-565.
[5] Lv J, An X, Jiang S, Yang Y, et al. Protoporphyrin IX Stimulates Melanogenesis, Melanocyte Dendricity, and Melanosome Transport Through the cGMP/PKG Pathway. Front Pharmacol. 2020 Sep 11;11:569368.
[6] Dibona-Villanueva L, Fuentealba D. Protoporphyrin IX-Chitosan Oligosaccharide Conjugate with Potent Antifungal Photodynamic Activity. J Agric Food Chem. 2022 Aug 3;70(30):9276-9282.
[7] Afonso S, Vanore G, Batlle A. Protoporphyrin IX and oxidative stress. Free Radic Res. 1999 Sep;31(3):161-70.
[8] Xu M, Zhou H, Liu Y, Sun J, et al. Ultrasound-Excited Protoporphyrin IX-Modified Multifunctional Nanoparticles as a Strong Inhibitor of Tau Phosphorylation and β-Amyloid Aggregation. ACS Appl Mater Interfaces. 2018 Oct 3;10(39):32965-32980.
Protoporphyrin IX是一种在血红素生物合成途径中的重要的卟啉类化合物，常被用于光动力疗法中 [1]。Protoporphyrin IX通过与铁离子结合形成亚铁原卟啉进而与珠蛋白结合生成血红蛋白。从而维持氧气运输和细胞呼吸功能[2]。Protoporphyrin IX在光动力疗法中主要作为光敏剂，能够吸收特定波长的光并产生活性氧，从而对病变组织或肿瘤细胞实现精准打击[3]。此外，还可利用Protoporphyrin IX的荧光成像（激发光波长为488nm，发射光波长为620nm）改善手术结果[4]。
在体外，Protoporphyrin IX（10-30μM）处理SK-MEL-2黑色素瘤细胞和人正常黑色素细胞（HNM）48小时，显著促进黑色素合成，增加酪氨酸酶活性及MITF、酪氨酸酶、TRP-1和TRP-2的表达水平，同时促进黑色素细胞树突形成和黑色素小体运输[5]。Protoporphyrin IX与壳寡糖（CH）形成的新型共轭物CH−PPIX（0.005%，w/v）在可见光照射下对青霉菌表现出100%的抑制效率。该共轭物通过单线态氧的生成导致孢子摄取和光诱导的膜损伤，从而发挥抗真菌作用[6]。
在体内，Protoporphyrin IX（3.5mg/kg）单剂量或每日一次连续5天腹腔注射给小鼠。单剂量后2小时，小鼠肝脏中卟啉积累达到峰值。5次剂量后，Protoporphyrin IX积累诱导氧化应激，导致肝脏损伤严重，同时损害抗氧化系统[7]。Protoporphyrin IX修饰的氧化介孔碳纳米球（1mg/kg）通过尾静脉注射于APP/PS1转基因小鼠模型中，通过聚焦超声（US）激发后，Protoporphyrin IX修饰的氧化介孔碳纳米球能够有效穿越血脑屏障（BBB），显著抑制Tau蛋白磷酸化和β-淀粉样蛋白（Aβ）聚集，提高小鼠的认知水平[8]。