The adipose tissue cell type enriched transcriptome

Adipose tissue cell type enriched transcriptome: Summary

Genes with predicted cell type specificity within visceral or subcutaneous adipose tissue are detailed below (Table 1 and 2, respectively). Identified enriched genes are subdivided into 3 specificity categories, based on the difference between the enrichment score in the corresponding cell type, compared to the other cell types profiled in the tissue (see Methods Summary page for details):

• Predicted specificity: ´Very high´ - Differential score vs. other profiled cell types within the tissue >0.35
• Predicted specificity: ´High´ - Differential score vs. other profiled cell types within the tissue >0.25
• Predicted specificity: ´Moderate´ - Differential score vs. other profiled cell types within the tissue >0.15

Table 1. Number of genes in each specificity category in the visceral adipose cell types.

Figure 1. Bar plot of the number of enriched genes in the cell types of the visceral adipose tissue, divided by specificity category

Table 2. Number of genes in each specificity categoriy in the subcutaneous adipose cell types.

Figure 2. Bar plot of the number of enriched genes in the cell types of the subcutaneous adipose tissue, divided by specificity category

Adipose tissue cell type enriched transcriptome: Illustrative examples

Adipocytes

Adipocytes are the predominant cell type found in adipose tissue. The mature adipocyte has several tasks, the most obvious being storage of lipids as an energy depot and metabolism of these lipids according to systemic needs. The lipids are stored as lipid droplets, that contribute to the cells’ high buoyancy, large size and round shape. Adipocytes also secrete several important signaling molecules, known as adipokines. Through adipokine secretion, adipocytes play an important role in regulating the energy balance and metabolic pathways in the body.

The active processes of lipogenesis and lipolysis in adipocytes is reflected by the high expression of lipid metabolic pathway genes, such as Acyl-CoA Synthetase Long Chain Family Member 1 (ACSL1), and other accessory molecules, such as Perilipin 4 (PLIN4), which coats lipid droplets to protect them from lipases. Protein Kinase CAMP-Dependent Type II Regulatory Subunit Beta (PRKAR2B), a signaling regulatory subunit involved in adipocyte maturation, and Microsomal Glutathione S-Transferase 1 (MGST1), an antioxidant enzyme that protects cells from lipid peroxidation, were also classified as having specificity in adipocytes in both visceral and subcutaneous adipose tissue.

ACSL1 - Adipose subcutaneous
ACSL1
PLIN4 - Adipose subcutaneous
PLIN4
PRKAR2B - Adipose subcutaneous
PRKAR2B
MGST1 - Adipose subcutaneous
MGST1

Adipose progenitor cells

Adipose progenitor cells are a transient cell type, with characteristics of both mesenchymal/fibroblastic cells and adipocytes. Adipose progenitor cells is a broad term, with cells in this category covering multiple developmental stages within the adipogenic pathway. These cells resemble an early stage of adipocyte development, before markers of stem cells or multipotent progenitors are lost following differentiation.

Genes classified as having specificity in adipose progenitor cells include Mannose Receptor C Type 2 (MRC2), which plays a role in extracellular matrix remodeling, Cadherin 11 (CDH11), which plays a role in calcium-dependent cell-cell adhesion, as well as genes with unknown function such as Deleted In Primary Ciliary Dyskinesia Homolog (DPCD).

MRC2 - Adipose subcutaneous
MRC2
CDH11 - Adipose subcutaneous
CDH11

Mesothelial cells

Mesothelial cells form a flattened and squamous monolayer that line both the serosal cavities and the organs within. They have several protective functions, including creating a low friction surface so that organs can move freely, as well as protecting organs within the cavity by transporting required molecules and cells across the serous membrane, while keeping microbes and other potential dangers out. They have also been found to be involved in inflammatory responses and wound healing, in addition to expressing pro- and anti -coagulant factors. In adipose tissue, mesothelial cells have only been identified in visceral depots and seem to be absent in subcutaneous depots.

Mesothelial cells are of mesoderm origin, and genes classified as having specificity include keratins such as KRT8 and KRT19, kallikreins such as KLK7 and KLK8, as well as genes related to coagulation such as the anticoagulant protein Annexin A8 (ANXA8).

Relevent publications

Norreen-Thorsen M et al., A human adipose tissue cell-type transcriptome atlas. Cell Rep. (2022)
PubMed: 35830816 DOI: 10.1016/j.celrep.2022.111046