Objective:To explore the therapeutic effect of adipose-derived stem cells (ADSC) on long-wave UV damage in mouse skin in order to provide ideas for the treatment of skin photodamage.Methods:The inguinal and perirenal adipose tissues of C57BL/6 mice were extracted and processed to obtain mouse ADSCs, and the surface markers, adipogenic and osteogenic differentiation capabilities were identified. The mouse photoaging model was irradiated with the SS-03AB UV illuminator, the total UVB dose was 9.45 J/cm 2, and the total UVA dose was 94.5 J/cm 2. Experimental mice (72 in total) were divided into normal group, model group, DMEM (medium) group and ADSC group, each with 18 mice. In the normal group and model group, the materials were taken two weeks after the end of irradiation. After irradiation, the ADSC group was given a subcutaneous injection of 200 μl ADSC suspension, and the DMEM group was given 200 μl of serum-free medium for treatment, and the materials were taken for pathological staining after 2 weeks. The experimental data was processed by analysis of variance. This study was carried out from August 2018 to July 2019 in the First Affiliated Hospital of Zhengzhou University. Results:The extracted cells were identified as adipose-derived stem cells. HE staining showed that the inflammatory cell infiltration in the ADSC group was significantly reduced compared with the DMEM group ( t=20.649, P<0.001) and the normal group ( t=16.147, P<0.001), and the thickness of the dermis layer was significantly increased. Masson staining showed collagen fibers were arranged neatly and the density increased significantly after ADSC treatment. Conclusions:Subcutaneous injection of ADSC can reduce inflammation, promote collagen tissue proliferation, increase the thickness of the dermis, effectively resist inflammatory damage and collagen breakdown caused by UVB.

Approximately 140 million people worldwide are homozygous carriers of APOE4 (ε4), a strong genetic risk factor for late onset familial and sporadic Alzheimer's disease (AD), 91% of whom will develop AD at earlier age than heterozygous carriers and noncarriers. Susceptibility to AD could be reduced by targeted editing of APOE4, but a technical basis for controlling the off-target effects of base editors is necessary to develop low-risk personalized gene therapies. Here, we first screened eight cytosine base editor variants at four injection stages (from 1- to 8-cell stage), and found that FNLS-YE1 variant in 8-cell embryos achieved the comparable base conversion rate (up to 100%) with the lowest bystander effects. In particular, 80% of AD-susceptible ε4 allele copies were converted to the AD-neutral ε3 allele in human ε4-carrying embryos. Stringent control measures combined with targeted deep sequencing, whole genome sequencing, and RNA sequencing showed no DNA or RNA off-target events in FNLS-YE1-treated human embryos or their derived stem cells. Furthermore, base editing with FNLS-YE1 showed no effects on embryo development to the blastocyst stage. Finally, we also demonstrated FNLS-YE1 could introduce known protective variants in human embryos to potentially reduce human susceptivity to systemic lupus erythematosus and familial hypercholesterolemia. Our study therefore suggests that base editing with FNLS-YE1 can efficiently and safely introduce known preventive variants in 8-cell human embryos, a potential approach for reducing human susceptibility to AD or other genetic diseases.
Humans ; Apolipoprotein E4/genetics* ; Cytosine ; Mutation ; Blastocyst ; Heterozygote ; Gene Editing ; CRISPR-Cas Systems