ANTI-POLLUTION 15
Preventing epigenetic changes fights urban pollution
n Daniel Schmid, Franziska Wandrey, Esther Belser, Fred Zülli - Mibelle Biochemistry, Switzerland
Environmental pollution is one of the major areas of concern when it comes to skin ageing. In particular, air pollution is directly in contact with our skin and it contributes to skin ageing on a daily basis. The main sources of air pollution are industrial combustion (diesel exhaust fumes and coal), traffic and construction works. Air pollution consists of gases such as ozone and very fine particles that are known as particulate matter (PM). These particles, which are between 0.1 μm – 10 μm in size, can remain in the atmosphere for weeks and contain toxic compounds such as heavy metals and allergens. Particulate matter is especially dangerous for the skin as it not only sits on the surface but can also penetrate into pores and therefore transport toxic substances into deeper skin layers. In combination with exposure to UV light, these particles cause oxidisation reactions within the skin, which lead to the formation of reactive oxygen species (ROS), inflammation and the loss of collagen. ROS can cause protein carbonylation, and these damaged proteins contribute to skin ageing. Furthermore, lipid peroxidation caused by ROS leads to skin barrier dysfunction, which creates a vicious cycle as more PM can enter the skin. The result is irritated, uneven skin that will age more rapidly.
Expression of detox and antioxidant enzymes in the skin It is obvious that our cells are in constant danger by toxic influences from the environment and thus need an efficient defence or detoxification system. Fortunately, our cells are able to produce enzymes that assist in the detoxification and removal of toxic substances. The genes encoding for detoxification and antioxidant enzymes, which are also called phase II enzymes, are activated by a specific mechanism. The transcription of these genes is regulated by a special control sequence in the promoter region of the gene. To start the expression of detoxification and antioxidant enzymes, a specific protein interacts with this control sequence. This “switch-on-protein”, which
November 2018 Abstract
Environmental pollution is one of the main contributing factors towards skin ageing and a dull complexion. For full protection, only a multi-level approach will succeed. Here an approach is described where a first line of defence is built up by a film-forming polysaccharide complex which physically prevents binding of pollutants. Activation of the cell’s own detoxification system is used as the second line of defence. And because pollution also induces epigenetic changes with long-term effects, a third line of defence was established where these epigenetic changes are prevented or reversed.
Chromosome
Histone tail with chemical tags
Histone
DNA strand
Methylation Phosphorylation Acetylation
Figure 1: Epigenetic changes on histone proteins which are responsible for the packaging and organisation of the DNA strand.
is called transcription factor Nrf2, is normally blocked by the repressor Keap1. A stimulus such as oxidative stress can disrupt the Nrf2-Keap1 complex. The released Nrf2 then binds to the control sequence and cells start to produce detoxification and antioxidant enzymes. In this way, cells can react to their environment by producing the correct response enzymes. Interestingly, a molecule found in plants of the Brassicaceae family, sulforaphane, has also been shown to disrupt the Nrf2-Keap1 complex and therefore activate the cellular detoxification system.
In this work, an extract of garden cress
sprouts (Lepidium sativum, belonging to the Brassicaceae family) was used as activator of the detoxification system in the skin. Cress sprouts have the highest concentration of sulforaphane.
Air pollution induces epigenetic changes in the skin
Epigenetics, which studies modulation of gene expression caused by mechanisms other than changes in the DNA sequence, can explain how environmental factors influence our body. Whereas oxidative stress acts at the moment, epigenetic modifications may lead to a long-term effect, even when the environmental stress is not present anymore. This is the reason why air pollution should be analysed for epigenetic effects. Epigenetics is based on chemical modification, mainly methylation or acetylation, of the nucleosome which comprises the DNA and histone proteins. The histone proteins are responsible for the packaging and organisation of the DNA (Fig 1). Modifications of histone proteins define the access of transcription factors to
PERSONAL CARE EUROPE
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104
