Advanced Glycation End Products Effects on Adipocyte Niche Stiffness and Cell Signaling

Abstract

Adipose tissue metabolism under hyperglycemia results in Type II diabetes (T2D). To better understand how the adipocytes function, we used a cell culture that was exposed to glycation by adding intermediate carbonyl products, which caused chemical cross-linking and led to the formation of advanced glycation end products (AGEs). The AGEs increased the cells and their niche stiffness and altered the rheological viscoelastic properties of the cultured cells leading to altered cell signaling. The AGEs formed concomitant with changes in protein structure, quantified by spectroscopy using the 8-ANS and Nile red probes. The AGE effects on adipocyte differentiation were viewed by imaging and evidenced in a reduction in cellular motility and membrane dynamics. Importantly, the alteration led to reduced adipogenesis, that is also measured by qPCR for expression of adipogenic genes and cell signaling. The evidence of alteration in the plasma membrane (PM) dynamics (measured by CTxB binding and NP endocytosis), also led to the impairment of signal transduction and a decrease in AKT phosphorylation, which hindered downstream insulin signaling. The study, therefore, presents a new interpretation of how AGEs affect the cell niche, PM stiffness, and cell signaling leading to an impairment of insulin signaling.

Advance Glycation End-products accelerate amyloid deposits in adipocyte’s lipid droplets

“…The involvement of adipocytes in the internalization and metabolism of glucose led us to examine how the formation of AGEs can affect cellular activity and specifically the differentiation capacity of 3T3-L1 cells. As already discussed, we have previously reported that treating cell cultures with the carbonyl compounds MGO and GAD decreases the level of adipogenesis (LOA) (25). Here, we extended the study to changes in adipocyte morphology and specifically to effects on cellular area and LD size.…”

“…We have previously reported an altered LOA in cells treated with MGO/GAD (25). This was extended here to an examination of the effects of the carbonyl compound on lipolysis ( The autophagy process was monitored by staining for LC3 II expression, a marker protein for autophagosome vesicles and provides the outcome as a puncta assay.…”

“…We have previously reported an altered LOA in cells treated with MGO/GAD (25). This was extended here to an examination of the effects of the carbonyl compound on lipolysis (Fig 2), the formation of amyloids by imaging ThT + LDs (Fig 3), and by RAMAN spectroscopy (Fig 4).…”

“…The connection between AGEs formation and the deposition of amyloidogenic fibrils in adipocytes may be important in understanding the patho-physiology of adipose tissue. The glycation creates irreversible misfolded protein structures and the formation of aggregates as we recently have shown for serum albumin (14), and in an in vitro cell system under glycated conditions (25).…”

Receptor for the Advanced Glycation End Products (RAGE) Pathway in Adipose Tissue Metabolism

“…Regardless of the direct impact on adipocytes, AGE formation in hyperglycemic conditions damages other components of adipose tissue. Recent studies on 3T3-L1 preadipocytes suggest that the accumulation of AGEs in the ECM, independently of the RAGE pathway, impairs adipocyte differentiation [ 36 ]. In addition, through ECM modification, AGEs have direct effects on cell niches and plasma membranes via loss of their plasticity and therefore induce alterations in cellular signaling and cytoskeletal organization.…”