Cryo-electron microscopy of adipose tissue extracellular vesicles in obesity and type 2 diabetes mellitus

Abstract

Extracellular vesicles (EVs) are cell-derived membrane vesicles which play an important role in cell-to-cell communication and physiology. EVs deliver biological information from producing to recipient cells by transport of different cargo such as proteins, mRNAs, microRNAs, non-coding RNAs and lipids. Adipose tissue EVs could regulate metabolic and inflammatory interactions inside adipose tissue depots as well as distal tissues. Thus, adipose tissue EVs are assumed to be implicated in obesity-associated pathologies, notably in insulin resistance and type 2 diabetes mellitus (T2DM). In this study we for the first time characterize EVs secreted by visceral (VAT) and subcutaneous adipose tissue (SAT) of patients with obesity and T2DM with standard methods as well as analyze their morphology with cryo-electron microscopy. Cryo-electron microscopy allowed us to visualize heterogeneous population of EVs of various size and morphology including single EVs and EVs with internal membrane structures in samples from obese patients as well from the control group. Single vesicles prevailed (up to 85% for SAT, up to 75% for VAT) and higher proportion of EVs with internal membrane structures compared to SAT was typical for VAT. Decreased size of single and double SAT EVs compared to VAT EVs, large proportion of multilayered EVs and all EVs with internal membrane structures secreted by VAT distinguished obese patients with/without T2DM from the control group. These findings could support the idea of modified biogenesis of EVs during obesity and T2DM.

Downregulation of Exosomal hsa-miR-551b-3p in Obesity and Its Link to Type 2 Diabetes Mellitus

“…It is worth noting that the size distribution and concentration of EVs in serum from men with T2DM or normal glucose tolerance were not different [21]. We earlier analyzed the adipose tissue EV structure by means of cryo-electron microscopy and found no size or morphological differences between such EVs from obese patients with and without T2DM [14]. Observed differences such as the increased total proportion of EVs with internal membrane structures were likely due to obesity-associated disturbance of EV biogenesis [14].…”

“…We earlier analyzed the adipose tissue EV structure by means of cryo-electron microscopy and found no size or morphological differences between such EVs from obese patients with and without T2DM [14]. Observed differences such as the increased total proportion of EVs with internal membrane structures were likely due to obesity-associated disturbance of EV biogenesis [14]. The amount of EVs secreted by obese adipose tissue increases, and their influence on gene expression in target tissues is supposed to be greater, which can result in the development of obesity-related comorbid diseases [23].…”

“…Recently, we provided the first evidence concerning the morphological changes in EVs derived from adipose tissue during obesity [14]. Moreover, studies demonstrated that the transfer of adipose-tissue-released EVs from ob/ob mice induced insulin resistance, adipose inflammation, and hepatic steatosis in lean mice [15,16].…”

Extracellular Vesicles: Techniques and Biomedical Applications Related to Single Vesicle Analysis

“…Individual EVs secreted by visceral (VAT) and subcutaneous adipose tissue (SAT) were observed by cryo-electron microscopy. It was found that compared with healthy individuals, the EVs secreted by VAT in T2DM patients had a larger proportion of multilayer structures and an intimal structure, indicating the biological changes of EVs …”

“…It was found that compared with healthy individuals, the EVs secreted by VAT in T2DM patients had a larger proportion of multilayer structures and an intimal structure, indicating the biological changes of EVs. 217 Pregnancy Complications. It has been found that the concentration of placental EVs (PEVs) released from the placenta is elevated in pregnancy complications such as preeclampsia, gestational diabetes mellitus, etc.…”