Cover Story Current Issue

Excessive lipid accumulation in adipose tissue triggers hypertrophy and stress of adipocytes, leading to infiltration of proinflammatory immune cells, fibrosis and adipocyte cell death, collectively referred to as adipose tissue dysfunction. As consequence, adipocytes capacity to store lipids is impaired and fat is ectopically accumulated in organs such as muscle, liver and pancreas, a condition that promotes organ dysfunction and insulin resistance, contributing to the pathogenesis of type 2 diabetes (T2D).

Although fat accumulation in human pancreas was described decades ago, it has for long remained an underexplored facet of ectopic fat distribution. Pancreatic fat has been associated with improved insulin secretion in normoglycaemic subjects, but with impaired insulin secretion in patients at increased risk of T2D. Furthermore, T2D diabetes remission, i.e. recovery of beta cell function was accompanied by reduction of pancreatic fat. These clinical observations point to the controversial role of pancreatic fat in insulin secretion, and emphasize the need for experimental evidence demonstrating plausible lipolysis derived fatty acids-/secretome-mediated effects of pancreatic adipocytes in islets. To date, detailed studies on the mechanistic interactions between pancreatic adipocytes and insulin secretion remain sparse, as reliable in vitro models replicating the unique properties of these cells have been lacking.

Full text

 

Current Issue

Thyroid hormone receptor beta (THRβ1) is the major regulator of T3 action in human iPSC-derived hepatocytes

Lorraine Soares De Oliveira, Joseph E. Kaserman, Anne H. Van Der Spek, Nora J. Lee, ... Anthony N. Hollenberg

Thyroid hormone receptor beta (THRβ1) is the major regulator of T3 action in human iPSC-derived hepatocytes

 

Objective

Thyroid hormone (TH) action is mediated by thyroid hormone receptor (THR) isoforms. While THRβ1 is likely the main isoform expressed in liver, its role in human hepatocytes is not fully understood.

Methods

To elucidate the role of THRβ1 action in human hepatocytes we used CRISPR/Cas9 editing to knock out THRβ1 in induced pluripotent stem cells (iPSC). Following directed differentiation to the hepatic lineage, iPSC-derived hepatocytes were then interrogated to determine the role of THRβ1 in ligand-independent and -dependent functions.

Results

We found that the loss of THRβ1 promoted alterations in proliferation rate and metabolic pathways regulated by T3, including gluconeogenesis, lipid oxidation, fatty acid synthesis, and fatty acid uptake. We observed that key genes involved in liver metabolism are regulated through both T3 ligand-dependent and -independent THRβ1 signaling mechanisms. Finally, we demonstrate that following THRβ1 knockout, several key metabolic genes remain T3 responsive suggesting they are THRα targets.

Conclusions

These results highlight that iPSC-derived hepatocytes are an effective platform to study mechanisms regulating TH signaling in human hepatocytes.

 

Articles in Press

Thyroid hormone receptor beta (THRβ1) is the major regulator of T3 action in human iPSC-derived hepatocytes

Lorraine Soares De Oliveira, Joseph E. Kaserman, Anne H. Van Der Spek, Nora J. Lee, ... Anthony N. Hollenberg

Thyroid hormone receptor beta (THRβ1) is the major regulator of T3 action in human iPSC-derived hepatocytes

 

Objective

Thyroid hormone (TH) action is mediated by thyroid hormone receptor (THR) isoforms. While THRβ1 is likely the main isoform expressed in liver, its role in human hepatocytes is not fully understood.

Methods

To elucidate the role of THRβ1 action in human hepatocytes we used CRISPR/Cas9 editing to knock out THRβ1 in induced pluripotent stem cells (iPSC). Following directed differentiation to the hepatic lineage, iPSC-derived hepatocytes were then interrogated to determine the role of THRβ1 in ligand-independent and -dependent functions.

Results

We found that the loss of THRβ1 promoted alterations in proliferation rate and metabolic pathways regulated by T3, including gluconeogenesis, lipid oxidation, fatty acid synthesis, and fatty acid uptake. We observed that key genes involved in liver metabolism are regulated through both T3 ligand-dependent and -independent THRβ1 signaling mechanisms. Finally, we demonstrate that following THRβ1 knockout, several key metabolic genes remain T3 responsive suggesting they are THRα targets.

Conclusions

These results highlight that iPSC-derived hepatocytes are an effective platform to study mechanisms regulating TH signaling in human hepatocytes.

 

You are what you eat

Here is a video of Vimeo. When the iframes is activated, a connection to Vimeo is established and, if necessary, cookies from Vimeo are also used. For further information on cookies policy click here.

Auf Werbeinhalte, die vor, während oder nach Videos von WEBSITE-URL eingeblendet werden, hat WEBSITE-URL keinen Einfluss. Wir übernehmen keine Gewähr für diese Inhalte. Weitere Informationen finden Sie hier.