LOXL2 from human amniotic mesenchymal stem cells accelerates wound epithelialization by promoting differentiation and migration of keratinocytes.

Dan He,Xuewen Lin,Ping Shi,Yue Kang,Han Jiang,Yang Song,Xining Pang,Feng Zhao,Tao Zhang

doi:10.18632/aging.103384

Abstract

In this study, we identified wound healing-related proteins secreted by human amniotic epithelial cells (hAECs) and human amniotic mesenchymal stem cells (hAMSCs). We observed increased migration and reduced proliferation and differentiation when keratinocytes were co-cultured in media conditioned by hAECs (hAECs-CM) and hAMSCs (hAMSCs-CM). Label-free mass spectrometry and bioinformatic analyses of the hAECs-CM and hAMSCs-CM proteome revealed several proteins associated with wound healing, angiogenesis, cellular differentiation, immune response and cell motility. The levels of the proteins related to wound healing, including CTHRC1, LOXL2 and LGALS1, were significantly higher in hAMSCs-CM than hAECs-CM. LOXL2 significantly enhanced in vitro keratinocyte migration and differentiation compared to CTHRC1 and LGALS1. Moreover, LOXL2 enhanced keratinocyte migration and differentiation by activating the JNK signaling pathway. We observed significant reduction in the in vitro migration and differentiation of keratinocytes when co-cultured with medium conditioned by LOXL2-silenced hAMSCs and when treated with 10 μM SP600125, a specific JNK inhibitor. Treatment with hAMSCs-CM and LOXL2 significantly accelerated wound healing in the murine skin wound model. These findings show that LOXL2 promotes wound healing by inducing keratinocyte migration and differentiation via a JNK signaling pathway.

Highlights

Skin wound healing is a complex, evolutionarily conserved, and dynamic biological process that involves coordinated regulation of multiple cell types such as keratinocytes, fibroblasts, endothelial cells, macrophages, and platelets by numerous growth factors, cytokines and chemokines [1]
We analyzed the differentiation of hAMSCs and human amniotic epithelial cells (hAECs) into osteoblasts, adipocytes, and chondrocytes by staining the corresponding cultures with Alizarin Red, Oil Red O, and Alcian Blue, respectively
We observed that both hAMSCs and hAECs differentiated into osteoblasts, adipocytes and chondrocytes (Figure 1D, 1E)

Summary

Introduction

Skin wound healing is a complex, evolutionarily conserved, and dynamic biological process that involves coordinated regulation of multiple cell types such as keratinocytes, fibroblasts, endothelial cells, macrophages, and platelets by numerous growth factors, cytokines and chemokines [1]. Keratinocytes respond to traumatic stress and are integral to the re-epithelialization process required for wound repair [2]. The human amniotic membrane is composed of the amniotic mesenchymal stem cells (hAMSCs) and amniotic epithelial cells (hAECs). The MSCs are multipotent cells that can differentiate into multiple cell types. They have been used in human regenerative medicine. The MSC secretome supports the regenerative process in the damaged tissue by inducing angiogenesis, inhibiting apoptotic cell death, and modulating the immune response [17]. The hAMSCs secrete factors that are used in cell-free therapy for acute brain injury [18]

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Conclusion