Single-nuclei analysis reveals depot-specific transcriptional heterogeneity and depot-specific cell types in adipose tissue of dairy cows

Abstract

Adipose tissue (AT) is an endocrine organ with a central role on whole-body energy metabolism and development of metabolic diseases. Single-cell and single-nuclei RNA sequencing (scRNA-seq and snRNA-seq, respectively) analyses in mice and human AT have revealed vast cell heterogeneity and functionally distinct subtypes that are potential therapeutic targets to metabolic disease. In periparturient dairy cows, AT goes through intensive remodeling and its dysfunction is associated with metabolic disease pathogenesis and decreased productive performance. The contributions of depot-specific cells and subtypes to the development of diseases in dairy cows remain to be studied. Our objective was to elucidate differences in cellular diversity of visceral (VAT) and subcutaneous (SAT) AT in dairy cows at the single-nuclei level. We collected matched SAT and VAT samples from three dairy cows and performed snRNA-seq analysis. We identified distinct cell types including four major mature adipocytes (AD) and three stem and progenitor cells (ASPC) subtypes, along with endothelial cells (EC), mesothelial cells (ME), immune cells, and pericytes and smooth muscle cells. All major cell types were present in both SAT and VAT, although a strong VAT-specificity was observed for ME, which were basically absent in SAT. One ASPC subtype was defined as adipogenic (PPARG+) while the other two had a fibro-adipogenic profile (PDGFRA+). We identified vascular and lymphatic EC subtypes, and different immune cell types and subtypes in both SAT and VAT, i.e., macrophages, monocytes, T cells, and natural killer cells. Not only did VAT show a greater proportion of immune cells, but these visceral immune cells had greater activation of pathways related to immune and inflammatory response, and complement cascade in comparison with SAT. There was a substantial contrast between depots for gene expression of complement cascade, which were greatly expressed by VAT cell subtypes compared to SAT, indicating a pro-inflammatory profile in VAT. Unprecedently, our study demonstrated cell-type and depot-specific heterogeneity in VAT and SAT of dairy cows. A better understanding of depot-specific molecular and cellular features of SAT and VAT will aid in the development of AT-targeted strategies to prevent and treat metabolic disease in dairy cows, especially during the periparturient period.

White Adipose Tissue Heterogeneity in the Single-Cell Era: From Mice and Humans to Cattle

“…Mechanistic studies using bulk-and scRNAseq identified increased hypoxia-related gene expression in Dpp4 + Tcf21 lineage ASPCs located in mesothelium and activation of inflammatory and fibrotic programming in the interstitial Icam1 + population [101]. In contrast to mouse models, our recent snRNAseq analysis of abdominal SAT and omental VAT from dairy cows revealed a negligible gene expression of DPP4 and F3 (CD142) [33], which may suggest a species-specific origin and development of adipocytes.…”

“…Our recent work has identified vascular and lymphatic endothelial cell populations in both SAT and VAT of dairy cows. However, a higher frequency of these cells were observed in SAT, thus suggesting an increased angiogenic capacity of this depot compared to VAT [33].…”

A Cell Atlas of Thoracic Aortic Perivascular Adipose Tissue: a focus on mechanotransducers

“…The median number of unique genes and unique molecular identifier (transcripts), respectively, identified in each nucleus were 1,393 and 2,029 for taPVAT and 1,638 and 2,398 for BAT. Leiden clustering found 20 clusters (Figure S1) which were manually annotated based on marker genes and comparison to previously published adipose tissue datasets 11–14 identifying 8 major cell types, each represented in similar proportions except for mesothelial cells primarily being present in taPVAT (0.4%, 119 nuclei) compared to BAT (0.004%; 1 nucleus) (Figure 2C).…”

Sequence-based GWAS in 180 000 German Holstein cattle reveals new candidate genes for milk production traits

“…ADGRE1 was found to be highly expressed in the macrophage cells in the lactating murine mammary gland [134]. It was detected in periparturient dairy cows' visceral adipose tissue, in a study by Michelotti et al [135] that investigated differences between adipose tissue cells in their contribution to the development of metabolic diseases in cattle in the period before and after calving. Association analysis in pigs showed a significant association of this gene with eicosenoic acid content [136] 9 PRDM1…”