ESPE Abstracts

Background: Glypican-4 is a heparan sulphate proteoglycan. In addition to a membrane-bound glypican-4, a soluble form exists. Human and rodent adipose tissue were identified as source of circulating glypican-4. Glypican-4 serum levels are associated with obesity and insulin resistance, as in type 2 diabetes (T2D). Because of its positive effect on insulin sensitivity, glypican-4 might play a role in the development of obesity, insulin resistance, and T2D. We a...

Background: Pediatric patients with germline pathogenic variants in the tumor suppressor gene PTEN frequently develop cancer and adipose tissue overgrowth in the form of lipomas. While the canonical function of the phosphatase PTEN is to antagonize the growth promoting PI3K pathway, non-canonical PTEN functions e.g. in the nucleus are less well described. To uncover the mechanisms leading to lipoma formation related to PTEN mutations, we previously performed R...

Background: Cancer cells have a high NAD turnover rate due to their increased cell proliferation and DNA repair. Nicotinamide phosphoribosyltransferase (NAMPT) is the key enzyme of the NAD salvage pathway, a regulator of the intracellular NAD pool and of the activity of Sirtuins (SIRTs), a class of NAD-dependent deacetylases.Objective and hypotheses: Cancer cells are highly dependent on NAD and are expected to be more susceptible to an inhibition of NAD ...

Introduction: Leptin, an adipokine secreted mainly by adipose tissue, is a regulator of energy balance acting through central mechanisms on the hypothalamus. However, leptin has many functions regulating e.g., immune system and reproduction. Leptin exerts its biological effects through its receptor, the expression of which has been demonstrated in several tissues. There are several leptin receptor isoforms, but activation of only one of them, the long form, re...

Background: Bone development and remodeling are controlled by the phosphoinositid-3-kinase (PI3K) signaling pathway. We investigated the effects of downregulation of phosphatase and tensin homolog (Pten), a negative regulator of PI3K signaling, in osteoprogenitor cells.Methods: Femura, tibiae and bone marrow stromal cells (BMSCs) from mice with Cre-inducible Pten knockdown in cells expressing the transcription factor Ost...

Background: Signaling through the phosphoinositid-3-kinase (PI3K) pathway modulates bone development and remodeling. We aimed to dissect the role of phosphatase and tensin homolog (Pten), a negative regulator of PI3K signaling, in osteoprogenitor cells.Methods: Femura, tibiae and bone marrow stromal cells (BMSCs) from mice with Cre-inducible Pten knockdown in cells expressing the transcription factor Osterix (Pten cKO) a...

Obesity presents a major worldwide challenge, due to its numerous, severe adverse effects on health. This leads to a necessity to further investigate the mechanisms underlying lipid accumulation. The adipocytokine leptin may contribute to this process. While there already has been thorough research into central leptin action, deepening our understanding of leptin’s effects on whole-body energy homeostasis, relatively little is known about its auto- and paracrine effects....

Introduction&Aim: Activation of mechanistic target of rapamycin (mTOR) as a major regulator of adipogenesis and lipid accumulation is controlled by upstream regulators hamartin/tuberous sclerosis complex (TSC) 1 and tuberin/TSC2. Hamartin and tuberin form a protein complex that inhibits signal transduction to mTOR. The impact of TSC1 deficiency is not clearly defined in human adipose tissue. We identified a likely pathogenic TSC1 splicing variant in a lipo...

Background: Tuberous Sclerosis Complex Subunit 1 (TSC1) encodes for the growth inhibitory protein hamartin, which suppresses mTOR signaling. Patients with TSC1 pathogenic variants are prone to developing benign tumors in the brain, kidneys, heart, skin, lungs, and other organs. We identified a likely pathogenic heterozygous germline TSC1 splicing variant NM_000368.5: c.737 +3A>G, r.664_737del, p. (Pro222Valfs*8) in a boy ...