Single-nucleus transcriptomics suggests a cell-type perspective for the complexity of insulin sensitivity and resistance in human adipose tissue

Yulia Haim ¹ Or Lazarescu ¹ Idan Hekselman ¹ Matthias Blüher ³ Antje Koerner ⁴ Rinki Murphy ⁵ Esti Yeger-Lotem ^1,2 Assaf Rudich ^1,2

¹Clinical Biochemistry and Pharmacology, Ben-Gurion University of the Negev, Israel
²The National Institute of Biotechnology in the Negev, Ben-Gurion University of the Negev, Israel
³Department of Medicine, University of Leipzig, Germany
⁴Center for Pediatric Research, Hospital for Children & Adolescents, University of Leipzig, Germany
⁵Department of Medicine, University of Auckland, New Zealand

Introduction: Metabolic effect of insulin-signaling on cells comprising human adipose tissue(AT) has been extensively studied. Heterogenic cellular structure of human-AT is well known, and insulin-signaling pathway is complexed and regulated by various factors, among which can be found those that induce insulin sensitivity and those that cause insulin resistance. Aim was to evaluate the expression of different insulin-signaling pathway components at transcriptome-level using single-cell approach.

Methods: We used 10x-genomics kit for single-cell-transcriptomics to perform sNUC-RNA-sequencing analysis of 11/6 visceral/subcutaneous human-AT samples to determine the (mRNA) expression of different components of insulin signaling.

Results: Mining nuclear mRNA expression of different insulin signaling components showed that while insulin receptor(INSR) was highly expressed by adipocytes and endothelial cells, its expression in T and B cells was low. In addition, IRS1 and IRS2 were also mainly expressed by adipocytes and sub-populations of ASPc(IRS1) or sub-population of macrophages (IRS2). Looking downstream to insulin-receptor at AKT isoforms we observed that while AKT3 is ubiquitous in the AT, it is expressed only by one sub-population of adipocytes, while other adipocyte sub-populations expressed mainly AKT2(which was also expressed by ASPc). Expression of insulin-resistance – inducing-kinases: PKCε, PKCζ was also different among sub-populations of AT-cells. Similar phenomenon was observed in the expression of negative regulators of proximal insulin signaling such as SOCS3 and TLR4.

Conclusions: Using sNUC-RNA sequencing data we can suggest that insulin signals through different components in different cell types and insulin resistance in the human-AT is comprised of a complex of pathways that are cell-type-dependent.