172 SKIN PROTECTION Clock gene expression during 24 hours


1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0


0 5 ** ** ***


1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0


10 Time (hours) Cry1 gene expression during 24 hours


1.2 1.0 0.8 0.6 0.4 0.2 0.0


0 5 ** *** 10 Time (hours) 15 20 25


1.2 1.0 0.8 0.6 0.4 0.2 0.0


0 5 15 20 25 0 5 Bmal1 gene expression during 24 hours


** **


10 Time (hours) Rorα gene expression during 24 hours


15


20


25


*** ** 10 Time (hours) 15 20 25


Figure 3: Effect of UV-B exposure on primary keratinocytes Clock, Bmal1, Cry1 and Rorα gene expression during 24 hours. The statistical analysis was performed using two-tailed unpaired T-test compared to untreated keratinocytes (**p<0.01; ***p<0.001).


and BMAL1/ARNTL (Aryl hydrocarbon Receptor Nuclear Translocator Like), are actives. They bind an enhancer called E-box present in the promoter of several genes. This binding activates transcription of E-box containing genes and induces their expression. Among E-box containing genes are Cry1 (CRYptochrome circadian regulator 1) and Per (Period circadian regulator) which play roles in circadian clock. Theirs mRNA are translated in the cytoplasm, into proteins; CRY1 and PER.


During the night, they associate and


return in the nucleus where they inhibit CLOCK/BMAL1 activity, resulting in the


140 120 100 80 60 40 20 0


** 108% *** 102% ** *** 54% 36% 28% 18% BMAL1 CRY1 57% ** ** 48% * 30% 17%


 Basal level  UVB  UVB+Crocus sativus flower extract at 1% Clock


RORα


Figure 4: UVB and Crocus sativus flower extract effects on primary keratinocytes circadian clock genes expression 6 hours after exposure. The statistical analysis was performed using two-tailed unpaired T-test (*p<0.05; **p<0.01; ***p<0.001).


PERSONAL CARE EUROPE ** 29% 59%


inhibition of E-box containing genes transcription. Moreover, RRE, another type of enhancer present in the promoter of several genes, is a binding site for RORα (RAR Related Orphan Receptor A), a protein that activates transcription of RRE containing genes. This results in the transcription of Bmal1 gene. At the end of the night, CRY1/PER complex is degraded and new BMAL1 proteins are available, resulting in a new circadian cycle. As mentioned before, sun exposition may induce deleterious effects on skin. The aim of this study is to evaluate the effect of UVB exposure on human keratinocytes


180 160 140 120 100 80 60 40 20 0


** 145% ** 119% ** 92% 67% 64% *** 38% 16%


 Basal level  UVB  UVB+Crocus sativus flower extract at 1% Clock


BMAL1 CRY1 RORα


Figure 5: UVB and Crocus sativus flower extract effects on primary keratinocytes circadian clock genes expression 10 hours after exposure. The statistical analysis was performed using two-tailed unpaired T-test (*p<0.05; **p<0.01; ***p<0.001).


April 2019 * 27% 30% *** 90% * 43%


circadian clock and protective efficacy of a Crocus sativus flower extract. To fulfil this purpose, human primary keratinocytes were synchronised (dexamethasone 100nM) before a UVB exposure (20mJ/cm²). The expression of genes involved in circadian clock regulation was analysed by qPCR on a 24-hour kinetic and results were compared to unexposed UVB condition (Fig 2). Furthermore, synchronised keratinocytes have been treated with the active ingredient prior to UVB exposure, to evaluate active ability to restore circadian clock genes expression. Circadian clock genes have an oscillating


** 149%


Relative gene expression compared to T0


Relative quantification compared to T0 (Fold change)


Relative quantification compared to T0 (Fold change)


Relative gene expression compared to T0


Relative quantification compared to T0 (Fold change)


Relative quantification compared to T0 (Fold change)


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  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121  |  Page 122  |  Page 123  |  Page 124  |  Page 125  |  Page 126  |  Page 127  |  Page 128  |  Page 129  |  Page 130  |  Page 131  |  Page 132  |  Page 133  |  Page 134  |  Page 135  |  Page 136  |  Page 137  |  Page 138  |  Page 139  |  Page 140  |  Page 141  |  Page 142  |  Page 143  |  Page 144  |  Page 145  |  Page 146  |  Page 147  |  Page 148  |  Page 149  |  Page 150  |  Page 151  |  Page 152  |  Page 153  |  Page 154  |  Page 155  |  Page 156  |  Page 157  |  Page 158  |  Page 159  |  Page 160  |  Page 161  |  Page 162  |  Page 163  |  Page 164  |  Page 165  |  Page 166  |  Page 167  |  Page 168  |  Page 169  |  Page 170  |  Page 171  |  Page 172  |  Page 173  |  Page 174  |  Page 175  |  Page 176  |  Page 177  |  Page 178  |  Page 179  |  Page 180  |  Page 181  |  Page 182  |  Page 183  |  Page 184  |  Page 185  |  Page 186  |  Page 187  |  Page 188