Hair follicle regional specificity in different parts of bay Mongolian horse by histology and transcriptional profiling

Ruoyang Zhao,Tugeqin Bao,Togtokh Mongke,Wenxing Wang,Manglai Dugarjaviin,Wu Yihan,Dongyi Bai,Haige Han,Yiping Zhao,Bei Li

doi:10.1186/s12864-020-07064-1

Abstract

BackgroundDifferent morphological structures of hairs having properties like defense and camouflage help animals survive in the wild environment. Horse is one of the rare kinds of animals with complex hair phenotypes in one individual; however, knowledge of horse hair follicle is limited in literature and their molecular basis remains unclear. Therefore, the investigation of horse hair follicle morphogenesis and pigmentogenesis attracts considerable interest.ResultHistological studies revealed the morphology and pigment synthesis of hair follicles are different in between four different parts (mane, dorsal part, tail, and fetlock) of the bay Mongolian horse. Hair follicle size, density, and cycle are strongly associated with the activity of alkaline phosphatase (ALP). We observed a great difference in gene expression between the mane, tail, and fetlock, which had a greater different gene expression pattern compared with the dorsal part through transcriptomics. The development of the hair follicle in all four parts was related to angiogenesis, stem cells, Wnt, and IGF signaling pathways. Pigmentogenesis-related pathways were involved in their hair follicle pigment synthesis.ConclusionsHair follicle morphology and the activity of ALP differ among four body parts in bay Mongolian horse. Hair follicles of the different body parts of the are not synchronized in their cycle stages. GO terms show a regional specificity pattern between different skin parts of the bay Mongolian horse. These results provide an insight into the understanding of the biological mechanism of the hair follicle in other mammals.

Highlights

Different morphological structures of hairs having properties like defense and camouflage help animals survive in the wild environment
Hair follicle morphology and the activity of alkaline phosphatase (ALP) differ among four body parts in bay Mongolian horse
With high regional specificity, can be mainly characterized at the mane, dorsal part, tail, and fetlock. Few mammals have such complex hair phenotypes on one individual body; the horse is a good model for studying hair follicle morphology and development due to the morphological differences existing among breeds and even in the different body parts of the same animal (Fig. 1)

Summary

Introduction

Different morphological structures of hairs having properties like defense and camouflage help animals survive in the wild environment. With high regional specificity, can be mainly characterized at the mane, dorsal part, tail, and fetlock Few mammals have such complex hair phenotypes on one individual body; the horse is a good model for studying hair follicle morphology and development due to the morphological differences existing among breeds and even in the different body parts of the same animal (Fig. 1). The base color of a horse is generally classified into the black, chestnut, bay, or seal brown and is determined by two interacting loci (extension and agouti) that affect melanocyte function [4, 5] These two loci determine if eumelanin or phaeomelanin will be produced in their corresponding melanosome. Understanding the hair growth, cycle, and melanogenesis in different parts of horse skin provides insights and valuable information for studying the regional specificity of hair follicles in other mammals

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Conclusion