Biomimetic cell-adhesive ligand-functionalized peptide composite hydrogels maintain stemness of human amniotic mesenchymal stem cells

In vivo,stem cells reside in a three-dimensional(3D)extracellular microenvironment in which complicated biophysical and biochemical factors regulate their behaviors.Biomimicking of the stem cellmatrix interactions is an ideal approach for controlling the stem cell fate.This study investigates the effects of the incorporation of cell-adhesive ligands in 3D self-assembling peptide hydrogels to modulate stem cell survival,proliferation,maintenance of stemness,and osteogenic differentiation.The results show that the composite hydrogels were non-cytotoxic and effective for maintaining human amniotic mesenchymal stem cell(hAMSC)survival,proliferation and phenotypic characterization.The expression levels of pluripotent markers were also upregulated in the composite hydrogels.Under inductive media conditions,mineral deposition and mRNA expression levels of osteogenic genes of hAMSCs were enhanced.The increasing expression of integrin aand b-subunits for hAMSCs indicates that the ligandintegrin interactions may modulate the cell fate for hAMSCs in composite hydrogels.

Establishment and function of tissue-residenl nnate lymphoid cells in the skin

Innate lymphoid cells （ILCs） are a newly classified family of immune cells of the lymphoid lineage. While they could be found in both lymphoid organs and non-lym-phoid tissues, ILCs are preferentially enriched in barrier tissues such as the skin, intestine, and lung where they could play important roles in maintenance of tissue integrity and function and protection against assaults of foreign agents. On the other hand, dysregulated activation of ILCs could contribute to tissue inflammatory diseases. In spite of recent progress towards understanding roles of ILCs in the health and disease, mech-anisms regulating specific establishment, activation, and function of ILCs in barrier tissues are still poorly understood. We herein review the up-to-date understanding of tissue-specific relevance of ILCs. Particularly we will focus on resident ILCs of the skin, the outmost barrier tissue critical in protection against various foreign hazardous agents and maintenance of thermal and water balance. In addition, we will discuss remaining outstanding questions yet to be addressed.

CCR10 and its ligands in regulation of epithelial immunity and diseases

Epithelial tissues covering the external and internal surface of a body are constantly under physical,chemical or biological assaults.To protect the epithelial tissues and maintain their homeostasis,multiple layers of immune defense mechanisms are required.Besides the epithelial tissue-resident immune cells that provide the first line of defense,circulating immune cells are also recruited into the local tissues in response to challenges.Chemokines and chemokine receptors regulate tissue-specific migration,maintenance and functions of immune cells.Among them,chemokine receptor CCR10 and its ligands chemokines CCL27 and CCL28 are uniquely involved in the epithelial immunity.CCL27 is expressed predominantly in the skin by keratinocytes while CCL28 is expressed by epithelial cells of various mucosal tissues.CCR10 is expressed by various subsets of innate-like T cells that are programmed to localize to the skin during their developmental processes in the thymus.Circulating T cells might be imprinted by skin-associated antigen-presenting cells to express CCR10 for their recruitment to the skin during the local immune response.On the other hand,IgA antibody-producing B cells generated in mucosa-associated lymphoid tissues express CCR10 for their migration and maintenance at mucosal sites.Increasing evidence also found that CCR10/ligands are involved in regulation of other immune cells in epithelial immunity and are frequently exploited by epithelium-localizing or-originated cancer cells for their survival,proliferation and evasion from immune surveillance.Herein,we review current knowledge on roles of CCR10/ligands in regulation of epithelial immunity and diseases and speculate on related important questions worth further investigation.