Senolytics restore the contraction of the collagen gel based on senescent dermal fibroblasts culture
: A novel insight into the therapeutic approach to skin aging
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Presented by: Akira Hagino
Introduction
Dermal fibroblasts synthesize the extracellular matrix (ECM) and generate mechanical forces within the ECM for maintenance of the skin structure and skin remodeling. There is increasing evidence that senescent cells are accumulated in the skin including dermis with age and senescent dermal fibroblasts are associated with skin aging such as wrinkles and skin sagging. However, the underlying mechanism that these cells cause skin aging has not been elucidated fully. Therefore, in this study, we investigated the effect of senescence on the ability of fibroblasts to contract a three dimensional (3D) collagen type I gel in order to clarify the relationship between dermal fibroblast senescence and the change in skin morphology and function. Furthermore, the effects of senolytics, which selectively eliminate senescent cells, on collagen contraction were examined.
Methods
Collagen contraction assay was performed to investigate the contractility differences among the non-senescent fibroblasts (nSNCs), senescent fibroblasts (SNCs) induced by doxorubicin, and the combination of nSNCs and SNCs. The orientation of collagen fibers was observed using the second harmonic generation (SHG) with a multiphoton microscopy. DNA microarray was used to analyze the comprehensive gene expression of nSNCs cocultured with SNCs. ABT263, a drug that has been reported to selectively eliminate senescent cells, was used to evaluate the effects of senolytics on collagen gel contraction recovery.
Results
The contraction of SNC-populated 3D collagen gel, referred to as “aged dermal model”, was found to be dramatically lower than that of nSNC-populated collagen gel, referred to as “young dermal model ”. Interestingly, decreased collagen gel contraction due to SNCs was also observed even in the presence of an adequate number of nSNCs sufficient to contract the gel. Although the thicker bundles and the orientation of collagen fibrils were observed on SHG imaging in the young dermal model, they were not found in aged dermal model. DNA microarray revealed that the expression of the kinesin superfamily genes was lower in nSNCs cocultured with SNCs than in only nSNCs. Finally, the number of SNCs was decreased drastically in aged dermal model treated with ABT263 and, consequently the gel contractility was restored.
Conclusion
Our findings demonstrate that the decreased ability of SNCs to contract collagen gel might cause dermal ECM morphological changes with skin aging. Moreover, we found that the elimination of senescent cells restores the collagen gel contractility. These results may lead to novel therapeutic advances for skin aging.
Dermal fibroblasts synthesize the extracellular matrix (ECM) and generate mechanical forces within the ECM for maintenance of the skin structure and skin remodeling. There is increasing evidence that senescent cells are accumulated in the skin including dermis with age and senescent dermal fibroblasts are associated with skin aging such as wrinkles and skin sagging. However, the underlying mechanism that these cells cause skin aging has not been elucidated fully. Therefore, in this study, we investigated the effect of senescence on the ability of fibroblasts to contract a three dimensional (3D) collagen type I gel in order to clarify the relationship between dermal fibroblast senescence and the change in skin morphology and function. Furthermore, the effects of senolytics, which selectively eliminate senescent cells, on collagen contraction were examined.
Methods
Collagen contraction assay was performed to investigate the contractility differences among the non-senescent fibroblasts (nSNCs), senescent fibroblasts (SNCs) induced by doxorubicin, and the combination of nSNCs and SNCs. The orientation of collagen fibers was observed using the second harmonic generation (SHG) with a multiphoton microscopy. DNA microarray was used to analyze the comprehensive gene expression of nSNCs cocultured with SNCs. ABT263, a drug that has been reported to selectively eliminate senescent cells, was used to evaluate the effects of senolytics on collagen gel contraction recovery.
Results
The contraction of SNC-populated 3D collagen gel, referred to as “aged dermal model”, was found to be dramatically lower than that of nSNC-populated collagen gel, referred to as “young dermal model ”. Interestingly, decreased collagen gel contraction due to SNCs was also observed even in the presence of an adequate number of nSNCs sufficient to contract the gel. Although the thicker bundles and the orientation of collagen fibrils were observed on SHG imaging in the young dermal model, they were not found in aged dermal model. DNA microarray revealed that the expression of the kinesin superfamily genes was lower in nSNCs cocultured with SNCs than in only nSNCs. Finally, the number of SNCs was decreased drastically in aged dermal model treated with ABT263 and, consequently the gel contractility was restored.
Conclusion
Our findings demonstrate that the decreased ability of SNCs to contract collagen gel might cause dermal ECM morphological changes with skin aging. Moreover, we found that the elimination of senescent cells restores the collagen gel contractility. These results may lead to novel therapeutic advances for skin aging.