Estefania Quesada-Masachs, M.D., Ph.D.

Exploring toxic effects of T1D patient’s serum in pancreatic β cells

FUNDED BY: the generosity of Larry & Tiki Spitcaufsky

Type 1 diabetes (T1D), an autoimmune disease that usually affects young people, is on the rise worldwide. But we still don’t completely understand the underlying processes that drive the destruction of insulin-producing β cells in the pancreas ultimately resulting in a lifelong dependency on insulin injections. A deeper knowledge of the immunological background of T1D is crucial to be able to offer better treatment options to patients.

Older findings indicated that autoantibodies and serum from T1D patients might directly harm β cells, but these studies relied on outdated technology and produced conflicting results. I propose to investigate the impact of serum of T1D patients on pancreatic β cell function and survival. Initial studies are designed to confirm that sera isolated from T1D patients exert toxic effects on pancreatic β cells and that these effects are not observed with sera from healthy controls. I will determine islet function by analyzing β cell proliferation and cellular death under different conditions. Subsequent experiments will seek to uncover the mechanisms that lead pancreatic β cell destruction.

As part of an ongoing collaboration, I will obtain human pancreatic islets from City of Hope in Los Angeles. Sera from individuals with and without T1D will be obtained from Benaroya Research Institute in Seattle. The serum samples will be fully characterized for the presence of autoantibodies and other molecules before the islets are cultured in the presence of T1D and non-diabetic control sera in special plates designed for culturing islet-organoids. During the last few months our lab has been optimizing the protocols to study pancreatic islet-organoids.

Confirming whether autoantibodies and sera from T1D patients have a direct deleterious effect on insulin-producing β cells could be of major importance to understand T1D pathogenesis, and this could completely re-write how we treat T1D patients.

Six-Month Project Update

I’m investigating the impact of serum of type 1 diabetes (T1D) patients on pancreatic beta cell function and survival. Using islets obtained through our collaboration with City of Hope hospital, I’ve begun determining the islet function through the glucose-stimulated insulin secretion test (GSIS). SPARK funds allowed me to purchase, and also upgrade the GSIS system with help from City of Hope, making it dynamic and more precise. The GSIS allows us to measure the response of the islets to different concentrations of glucose and other stimuli in real time, so we can measure variations in the islet insulin secretion by the minute. These variations tell us how functional the beta cells are at producing insulin and we can determine if they are unhealthy. Thus far, I’ve tested and identified some of the key antibodies for the project, including testing several antibodies to analyze beta cell death under different conditions. I’ve also calibrated the system to measure late cell death using the TUNEL staining. The high quality of this staining allows a precise quantification of the cells that are undergoing late cell death. My next steps are to identify early cell death markers, quantify the cytokines and other molecules in the human serum and further optimize the process of exposing the islets to human serum. Completing these steps will help determine if autoantibodies and sera from T1D patients have a direct deleterious effect on insulin-producing beta cells, which could help us understand T1D pathogenesis and completely re-write how we treat T1D patients.