Unfolding the pathogenesis of systemic sclerosis through epigenomics

As a group of autoimmune diseases, systemic sclerosis (scleroderma, SSc) is characterized by immune dysregulation, micro-vessels dominant obliteration, and the final fibrosis of the skin and or internal organs. Although the precise mechanisms are still unknown, increasing data shows that epigenetic mechanisms, such as DNA methylation, histone modification, and microRNA (miRNA), are strictly related to the pathogenesis of scleroderma. Epigenetic mechanisms, which can link genetics and environmental stress, represents a promising field in systemic sclerosis investigation. The objective of this review is, to sum up the current information about epigenetic alteration.

Consensus-Expressed CXCL8 and MMP9 Identified by Meta-Analyzed Perineural Invasion Gene Signature in Gastric Cancer Microarray Data

Sonic hedgehog signaling in epithelial tissue development

The Sonic hedgehog (SHH) signaling pathway is essential for embryonic development and tissue regeneration. The dysfunction of SHH pathway is involved in a variety of diseases, including cancer, birth defects, and other diseases. Here we reviewed recent studies on main molecules involved in the SHH signaling pathway, specifically focused on their function in epithelial tissue and appendages development, including epidermis, touch dome, hair, sebaceous gland, mammary gland, tooth, nail, gastric epithelium, and intestinal epithelium. The advance in understanding the SHH signaling pathway will give us more clues to the mechanisms of tissue repair and regeneration, as well as the development of new treatment for diseases related to dysregulation of SHH signaling pathway.

A Cascade of Wnt, Eda, and Shh Signaling Is Essential for Touch Dome Merkel Cell Development

Neural Hedgehog signaling maintains stem cell renewal in the sensory touch dome epithelium

The touch dome is a highly patterned mechanosensory structure in the epidermis composed of specialized keratinocytes in juxtaposition with innervated Merkel cells. The touch dome epithelium is maintained by tissue-specific stem cells, but the signals that regulate the touch dome are not known. We identify touch dome stem cells that are unique among epidermal cells in their activated Hedgehog signaling and ability to maintain the touch dome as a distinct lineage compartment. Skin denervation reveals that renewal of touch dome stem cells requires a perineural microenvironment, and deleting Sonic hedgehog (Shh) in neurons or Smoothened in the epidermis demonstrates that Shh is an essential niche factor that maintains touch dome stem cells. Up-regulation of Hedgehog signaling results in neoplastic expansion of touch dome keratinocytes but no Merkel cell neoplasia. These findings demonstrate that nerve-derived Shh is a critical regulator of lineage-specific stem cells that maintain specialized sensory compartments in the epidermis.

Merkel cells and touch domes: more than mechanosensory functions?

Perivascular Hair Follicle Stem Cells Associate with a Venule Annulus