Construction Of Single Cell Transcriptional Map Of Yak Lung Tissue And Analysis Of Cell Type Characteristics

Yak,as the only bovine animal that can survive at high altitude,has a good adaptability to the high altitude ecological environment of alpine,hypoxic,high altitude and high ultraviolet light.It is an indispensable and important animal species at high altitude.Its unique adaptive mechanism and action pathway of high altitude hypoxia make it an ideal animal model for studying the adaptability at high altitude.At present,although the single-cell transcriptional map of human and mouse lungs has been constructed,the transcriptional map of yak lungs has not been reported.In order to gain a deeper understanding of the cell types of yak lungs and their mechanisms of high altitude adaptability at the single-cell level,in this study,the lungs were used as organs to explore the high altitude adaptability of yaks,and the single-cell transcriptional profiles of yak lungs were successfully constructed for the first time using the single-cell transcriptome sequencing technology of 10 × Genomics,and the data sets were clustered.By referring to the classical marker genes in human and mouse single-cell transcriptome data and combining with the strategy of automated annotation,all cells in the yak lung were annotated.Gene Set Variation Analysis(GSVA)was then performed on different cells to provide a reference for subtype annotation in terms of function and further verify the reliability of the annotation results.Finally,RNA-seq was performed on the lung tissues of yaks and cattle,respectively,to explore the important cell types associated with high altitude adaptability of yaks by mapping the differential transcripts of yak vs cattle into the cell types of yak lungs.The main results are as follows:(1)We successfully constructed the single cell whole transcription map of yak lung tissue for the first time,and annotated it into 9 cell types according to the known marker genes in humans and mice,combined with the method of automatic annotation,and reclustered these 9 cell types to further distinguish the cell subtypes,and finally obtained the yak lung whole transcription map containing 9 cell types and 41 cell subtypes.(2)In the fibroblast subcluster,two new subtypes were defined: RYR2+Fib(involving calcium signaling pathway,c AMP signaling pathway,etc.)and NDNF+Fib(involving angiogenesis,NO-mediated signal transduction,etc.).(3)Through Gene Set Variation Analysis,it was found that the GSVA enrichment pathway of different cell subtypes were basically consistent with the function of marker gene and the cell itself,further verifying the accuracy of cell annotation results.(4)By mapping the RNA-seq differential transcripts of yak vs cattle into the cell types of yak lungs,it was found that the differential genes were mainly enriched in Monocytes and Dendritic cells,followed by Fibroblasts,Endothelial,Epithelial and B cells.Combined with GSVA pathway enrichment analysis and related papers,it is speculated that Myeloid cells and Fibroblasts play an important role in the adaptive evolution of hypoxia at high altitude in yaks.In summary,in this study,we successfully constructed a single-cell whole transcriptional map of yak lung tissue for the first time,and preliminarily analyzed the obtained data set,and also analyzed the data of the RNA-seq in combination with the single-cell transcriptome,providing a basis for us to further explore the unique adaptive evolutionary process of hypoxia at high altitude and the genetic mechanism at the single-cell level in yaks.