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Type 1 Diabetes Researcher Spotlight: Sambra Redick, PhD

Date Posted: Wednesday, October 06, 2021

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Dr. Redick is a senior research scientist in the laboratory of Dr. David Harlan.  Her work is focused on functional and transcriptional profiling of pancreatic islets from both diabetic and non-diabetic donors.  She is developing techniques to remove and study single islets from slices of human pancreas that we receive as members of the Network for Pancreatic Organ Donors with Diabetes (nPOD).  Sam uses methods that allow her to get transcriptional profiles of single cells from within those islets.

Since her arrival at the UMass Diabetes Center of Excellence (DCOE) in 2015, Sam’s research helped put to rest a decades old debate about beta cells.  She has also worked closely with Worcester Polytechnic Institute (WPI) engineers to develop a novel tool to improve the removal of individual islets from human pancreas slices to better investigate them.

Resolving a 30-year debate by locating beta cells in people with T1D that express important immune pathway gene products

By far the greatest genetic risk for T1D is driven by the expression of immune genes called “human leukocyte antigen class II” (HLA Class II) and yet human beta cells were thought by many, not capable of expressing HLA Class II and other important genes supporting HLA Class II function.  Collaborative research in the Harlan Lab definitively showed that beta cells from individuals with T1D express these important gene products.  Since they are immune system genes, it raised the question of whether this immune function is an important part of what T cells are seeing to trigger the autoimmune attack on beta cells.

Creating a tool to procure single islets

The Harlan Lab feels that since diabetes is a patchy disease with varying effects on islets that have widely varied sizes and cellular composition, studying single islets will be beneficial if we can investigate them individually.  Sam has been developing techniques to separate single islets including a halo of T cells around the edge of the islet, allowing them to study the importance of that ring of immune cells.  They’ve developed a novel tool to punch and recover individual islets from living pancreas slices for more in-depth investigation.

Collaborations within the UMass Diabetes Center of Excellence

The research in the Harlan Lab is focused on beta cells and what they may be doing to attract the attention of the immune system in the autoimmune attack of T1D. The UMass DCOE lab of Sally Kent, PhD is focused on T cells to investigate those immune cell’s role in the process.  When we receive pancreas samples to study, each lab is focused on their cell type of interest, and they also work together to understand the interactions of those cells and their role in the development of T1D.

A lifetime of scientific study

Sam’s interest in cell biology stems from a 4th grade science project she did on the topic of DNA replication. She grew up in South Carolina and became the first person in her family to finish college.

After serving in Japan during World War II, her father became a self-educated electronics and pneumatics mechanic at a paper mill.  Sam’s mother began working in a dress factory while still in high school and worked her way up to a position in motion economy, determining the most efficient way to cut and assemble dresses.

“My folks always told me I was going to college, and I decided in junior high that I wanted to attend college, but not just to get one degree, I wanted to get them all,” she said with a smile.

Sam studied genetics at University of Georgia, then earned both her master’s degree and PhD in molecular biology at Princeton University where she had planned to study virology.  “By that time, I thought transcription would be very important and control a lot of biology.”

Students were required to do three rotations to experience a variety of labs before committing.  Sam’s final rotation was in a laboratory that studied the extracellular matrix, which is secreted by cells and regulates processes by controlling cell communication.  “I was hooked,” she said.  “Much of the extracellular communication that passes through a cell involves the matrix in some way.”

Her first postdoctoral fellowship was at the University of North Carolina working in a lab that used mouse embryonic stem cells to study blood vessel development. 

sambra-redick-umass-medical-school.pngSam realized early on that she didn’t aspire to run her own lab, but rather enjoys performing research at the bench.  “I like working with my hands doing the physical experiments, and I love troubleshooting,” she said.

Her second postdoc position was at Duke University in a lab that was working on two completely different projects.  “At that point I didn’t necessarily care what the project was,” she said.   “I just wanted to investigate interesting questions and use cool tools!”  She got some papers published about cell adhesion and anti-adhesion, and then transitioned to the bacterial cell division side of the lab.

Joining UMass Medical School and the Diabetes Center of Excellence

She first arrived at UMass Medical School in 2003 working in the laboratory of Dr. Stephen Doxsey.  They studied cell division with a focus on the centrosome and mitotic spindle poles.  After 12 years in the Doxsey Lab, funding ran dry and Sam’s network on campus led to a position in the Harlan Lab in the UMass DCOE.

At that time, they obtained donated pancreatic islets from deceased diabetic and non-diabetic donors and separated them into single cells.  Those cells were stained and sorted into cell groups by hormones (insulin, glucagon, etc.).  Sam performed RNA-sequencing to examine the transcriptome of those cells to determine their messenger RNA molecules.  The Harlan Lab was looking for differences between beta cells from the islets of people who had T1D and those who were non-diabetic.  They compared cells from people who passed away during various phases of the disease process to investigate changes in gene expression and compared them to cells from people without diabetes.  The goal was to understand if beta cells do something to attract the attention of immune cells, thus causing the autoimmune attack, or if perhaps beta cells are simply “innocent bystanders.”

They soon determined that sorting cell groups by insulin could be missing important information since beta cells from people with T1D didn’t produce much insulin.  Sam started working on new techniques to interrogate single cells without regard to hormone expression.  Today they capture the cells from islets using a molecular biology process that captures single cells and labels the individual gene expression of each.  This process continues to produce gigabytes of data to be analyzed by our bioinformatician to identify cell types by their gene expression hallmarks and examine how the individual gene expression profiles vary.

Getting to know Sam

sambra-redick-umass-diabetes-beta-cells.pngSam and her husband share their home with two cats.  She enjoys growing a garden at home, especially vegetables that aren’t available locally.  “I’m a southerner, so we have a big okra patch, purple top turnips with the greens on,” she said.  “All the cliches of southern food.”  She enjoys cooking and compared it to lab work, because you follow a protocol, except “the experiment almost never fails so badly that you can’t have dinner,” she joked.

Sam’s favorite part of living in New England are the four seasons.  She enjoys fall foliage, winter sports like cross country skiing, and spring & summer activities such as hiking, kayaking, cycling and other outdoor activities.

Favorites

TV Shows: M.A.S.H., Star Trek Next Generation, Big Bang Theory
Movies: The Princess Pride, Harold and Maude
Restaurants: Eller’s for breakfast, Fatima’s Café, Nancy Chang’s, BT’s Smokehouse
Hobbies: Steam train enthusiast

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