An old proverb goes “The eyes are the window of the mind.”

However, vision problems have become one of the biggest worries for Chinese teenagers. How we can protect our eyes has also become the top concern for young teenagers and their families. The NHC of China conducted a special survey on myopia from September to December in 2020, covering 8,604 schools nationwide and screening 2.477 million students [1]. The results show that: in 2020, the overall near-sightedness rate of children and adolescents in our country was 52.7%. Among them, 14.3 percent of 6 years old, 35.6 percent of elementary school students, 71.1 percent of middle school students, and 80.5 percent of high school students. The data really surprises us, which also informs us it is urgent to put effort into eyesight protection.

Wearing eyeglasses can mitigate stress on eyesight but it doesn’t serve as a cure or a treatment of the damage. Members in SHSBNU_China teams tried to figure out the causes of eyesight impairment but found the cellular mechanism of the disease development is still unclear [2]. During literature search and expert interviews in ophthalmology departments (including Dr. Shao, LiGong: Doctor of Ophthalmology and Visual Development Science, visiting professor of pediatric visual development and ophthalmology), two factors emerged on the horizon, oxidative stress/damage and blue light irritation. Oxidative stress has been assumed to relate to progress of myopia and further eye diseases [2]; and blue light irritation is believed to cause irreversible damage to eye tissues by photochemical pathways [4]. Readers can refer to our Human Practices pages for more the expert interviews.

1.Reactive oxygen species (ROS) and reactive nit Rogen species (RNS) are important factors causing oxidative damage to proteins. Many biochemical reactions produce ROS and RNS, both of which can lead to genome instability and cell death.
2.Sunlight and electronic screens emit blue light. Blue light has short wavelength and great energy, which can penetrate human lens directly to the macular area of the eyes. Previous research explored that exposure to blue light can cause damage to retinal cells, leading to vision impairment or even loss.

Furthermore, is there anything resistant to both oxidative damage and blue light irritation? To answer this question, we spent a lot of time reading scientific papers, and we noticed anthocyanin, which produced by plants exhibits excellent characteristics.

Anthocyanins are natural pigments widely found in plants. They have been reported as health care products to assist many physiological functions, including eye protection and anti-aging effects.
Anthocyanin related products have been widely used in production and life, it is a safe and harmless wealth given by nature.

We plan to make several applications using anthocyanins to protect our eyes, for example contact lenses with a layer of anthocyanins dye, anthocyanin-containing eye-masks, anthocyanin-stained mobile phone film and so on. Anthocyanins can not only give beautiful colors to our product, but also can function in eyes protection.

So, the next question is where do anthocyanins in our daily life come from? We interviewed some professionals, and the answer is directly extraction from plants. However, Traditional anthocyanin extraction methods have two problems: First, anthocyanins are rarely present in free form. Second, the traditional extraction method of anthocyanins requires a large amount of organic reagents, and the yield is low.

Figure: Extraction of Anthocyanins via traditional methods [5].

Based on this, this year our project aims to construct an intact metabolic pathway in E.coli, to give them the ability to produce anthocyanins. Among the many species of anthocyanins, we focused on delphinidin, the powder of which generally show a pink-ish purple to blue-ish purple. E.coli is a widely used model organism in synthetic biology because of its greater ability to survive and better yield. The whole pathway to produce anthocyanins contains 7 enzymes, which can be listed as 4CL, CHS, CHI, F3H, F3’5’H, DFR and ANS. Each of them catalyzes a set of interlocking reactions. We used molecular biology and synthetic biology method to express enzymes in E.coli, so as to produce anthocyanins finally.

Figure: Synthesis pathway of delphinidin [6].

References:

[1] Q. Zhao, (July 2021) “Kindergarten and primary school are the key age groups for nearsightedness prevention and control,” National Health Committee, China; https://kepu.gmw.cn/2021-07/13/content_34990460.htm,
[2] Mérida S, Villar VM, Navea A, Desco C, Sancho-Tello M, Peris C, Bosch-Morell F. Imbalance Between Oxidative Stress and Growth Factors in Human High Myopia. Front Physiol. 2020 May 14;11:463. doi: 10.3389/fphys.2020.00463.
[3] Francisco BM, Salvador M, Amparo N. Oxidative stress in myopia. Oxid Med Cell Longev. 2015;2015:750637. doi: 10.1155/2015/750637.
[4] Ouyang X, Yang J, Hong Z, Wu Y, Xie Y, Wang G. Mechanisms of blue light-induced eye hazard and protective measures: a review. Biomed Pharmacother. 2020 Oct;130:110577. doi: 10.1016/j.biopha.2020.110577.
[5] J. Tan, Y. Han, B. Han, X. Qi, X. Cai, S. Ge, H. Xue, “Extraction and purification of anthocyanins: A review,” Journal of Agriculture and Food Research, vol. 8, 100306, 2022 Doi: 10.1016/j.jafr.2022.100306.
[6] J. Song, C. Guo, M. Shi, Anthocyanin Biosynthesis and Transcriptional Regulation in Plant, Molecular Plant Breeding, 2021, Vol.19, No.11, 3612-3620, DOI: 10.13271/j.mpb.019.003612