Endocrinology Objective: Sex steroid hormones like estrogens have a key role in the regulation of energy homeostasis and metabolism. In transwomen, gender-affirming hormone therapy like estradiol ... Show moreEndocrinology Objective: Sex steroid hormones like estrogens have a key role in the regulation of energy homeostasis and metabolism. In transwomen, gender-affirming hormone therapy like estradiol (in combination with antiandrogenic compounds) could affect metabolism as well. Given that the underlying pathophysiological mechanisms are not fully understood, this study assessed circulating estradiol-driven microRNAs (miRs) in transwomen and their regulation of genes involved in metabolism in mice. Methods: Following plasma miR-sequencing (seq) in a transwomen discovery (n = 20) and validation cohort (n = 30), we identified miR-224 and miR-452. Subsequent systemic silencing of these miRs in male C57Bl/6 J mice (n = 10) was followed by RNA-seq-based gene expression analysis of brown and white adipose tissue in conjunction with mechanistic studies in cultured adipocytes. Results: Estradiol in transwomen lowered plasma miR-224 and-452 carried in extracellular vesicles (EVs) while their systemic silencing in mice and cultured adipocytes increased lipogenesis (white adipose) but reduced glucose uptake and mitochondrial respiration (brown adipose). In white and brown adipose tissue, differentially expressed (miR target) genes are associated with lipogenesis (white adipose) and mitochondrial respiration and glucose uptake (brown adipose). Conclusion: This study identified an estradiol-drive post-transcriptional network that could potentially offer a mechanistic understanding of metabolism following gender-affirming estradiol therapy. Show less
Trinanes, J.; Dijke, P. ten; Groen, N.; Hanegraaf, M.; Porrini, E.; Rodriguez-Rodriguez, A.E.; ... ; Vries, A.P.J. de 2020
Active maintenance of beta-cell identity through fine-tuned regulation of key transcription factors ensures beta-cell function. Tacrolimus, a widely used immunosuppressant, accelerates onset of... Show moreActive maintenance of beta-cell identity through fine-tuned regulation of key transcription factors ensures beta-cell function. Tacrolimus, a widely used immunosuppressant, accelerates onset of diabetes after organ transplantation, but underlying molecular mechanisms are unclear. Here we show that tacrolimus induces loss of human beta-cell maturity and beta-cell failure through activation of the BMP/SMAD signaling pathway when administered under mild metabolic stress conditions. Tacrolimus-induced phosphorylated SMAD1/5 acts in synergy with metabolic stress-activated FOXO1 through formation of a complex. This interaction is associated with reduced expression of the key beta-cell transcription factor MAFA and abolished insulin secretion, both in vitro in primary human islets and in vivo in human islets transplanted into high-fat diet-fed mice. Pharmacological inhibition of BMP signaling protects human beta-cells from tacrolimus-induced beta-cell dysfunction in vitro. Furthermore, we confirm that BMP/SMAD signaling is activated in protocol pancreas allograft biopsies from recipients on tacrolimus. To conclude, we propose a novel mechanism underlying the diabetogenicity of tacrolimus in primary human beta-cells. This insight could lead to new treatment strategies for new-onset diabetes and may have implications for other forms of diabetes. Show less
Buitinga, M.; Assen, F.; Hanegraaf, M.; Wieringa, P.; Hilderink, J.; Moroni, L.; ... ; Apeldoorn, A. van 2017
While subcutaneous tissue has been proposed as a clinically relevant site for pancreatic islet transplantation, a major issue of concern remains, which is its poor vascular state. In an effort to... Show moreWhile subcutaneous tissue has been proposed as a clinically relevant site for pancreatic islet transplantation, a major issue of concern remains, which is its poor vascular state. In an effort to overcome this limitation, we present an efficient and reproducible method to form human composite islets (CIs) with proangiogenic cell types in a controlled manner using nonadherent agarose microwell templates. In this study, we assessed the three-dimensional structure, function, and angiogenic potential of human CIs with human mesenchymal stromal cells (hMSCs), with or without human umbilical vein endothelial cells (HUVECs), and preconditioned hMSCs (PC-hMSCs) in EGM-2 under shear stress. Distinct cellular rearrangements could be observed in CIs, but islet functionality was maintained. In vitro angiogenesis assays found significantly enhanced sprout formation in case of CIs. In particular, the number of sprouts emanating from CIs with PC-hMSCs was significantly increased compared to other conditions. Subsequent in vivo assessment confirmed the proangiogenic potential of CIs. However, in contrast to our in vitro angiogenesis assays, CIs with hMSCs and HUVECs exhibited a higher in vivo angiogenic potential compared to control islets or islets combined with hMSCs or PC-hMSCs. These findings highlight the importance and necessity of verifying in vitro studies with in vivo models to reliably predict, in this case, revascularization outcomes. Regardless, we demonstrate here the therapeutic potential of CIs with proangiogenic support cells to enhance islet revascularization at a clinically relevant, although poorly vascularized, transplantation site. Show less
