Lombardo Study Focuses on Cell Polarity Signaling

By Dirk Hoffman

“My interest as a scientist, the biggest thing that guides me, is I want to be thinking about fundamental things that make life as we know it,” says Andrew T. Lombardo, PhD, assistant professor of biochemistry in the Jacobs School of Medicine and Biomedical Sciences.

Lombardo’s lab focuses on studying human cell polarity and was recently awarded a five-year, $1.9 million grant from the National Institute of General Medical Sciences for its study titled “The Cytoskeletal Drivers of Cell Polarity.”

“At the core of it, the proteins, lipids and DNA — all the things that make up living things — have to be either functionally, structurally, mechanically, or compositionally different in one part of the cell than another part of the cell,” says Lombardo, principal investigator on the grant. “This process is so fundamental that it involves things like cell division, differentiation, and the ability to move, motility.”

Lombardo and his team are studying how cell polarity is signaled, building on existing information learned in identifying the critical players in human cell polarity.

“The people of the great city of Buffalo and some researchers currently in our department at the University at Buffalo played a very big role in the Human Genome Project,” he says. “Now we know a lot of the proteins that are important for cell polarity, but we don’t know how they work together or how they signal with each other to coordinate their actions. That is really the crux of this grant.”

Lombardo says his team is looking to answer a basic foundational question of “how is it exactly that the cell or any living thing can say ‘I need this structure to be here right at this exact location at this exact time?”’

“We study it in these really unique polarized cells called epithelial cells,” he says. “The epithelial cells in your gut, kidney and in the placenta, they all transfer nutrients. In the gut, it is from the food into the blood. In the placenta, it is from mother’s blood to the baby’s blood. In the kidney it is a little bit reversed — from the blood into the urinary tract.”

“But these cells have a polarity across them — this is the inside of the body on one side, and the other side is the outside of the body, and they need to move nutrients across that polarity.”

The researchers are studying structures called microvilli or “little fingers” that are formed on the apical side of the cell and stick out into the lumen to expand the surface area to increase the amount of nutrient transfer that takes place.

“How exactly does the cell produce this wonderful, cool and interesting structure only on the single surface that faces out?” Lombardo asks. “The cell must know that is the outside and it must get all the material there — the lipids, the proteins, all the biological materials that are needed to produce these structures — need to be moved from the sites of production to the apical surface. Once they are there, they must produce this structure. If it is not made, then there is no nutrient transfer.”

“So, this is essential. You could imagine the outcome of not having nutrient transfer in humans in that scenario.”

Lombardo says sometimes there are disease states in humans that are not lethal, and this often leads to either kidney or intestinal diseases.

Some of these include the proteins the researchers are studying. One of these proteins is called myosin IXb, which when mutated leads to celiac disease.

“It begs the question of how does this protein lead to nutrient transfer in the gut? And we found in our preliminary data that when myosin IXb is disrupted through these genetic mutations that these microvilli don’t form properly,” Lombardo says. “We believe that myosin IXb is playing a critical role in the creation of this nutrient transfer system and is regulated in part by the polarity determination of these cells.”

“This protein is a signaling molecule and it seems to play a role in signaling to the cell that this is the outside of the cell and we need to produce microvilli here, but we don’t understand how that occurs. One of the aims of the grant is to figure out exactly what myosin IXb is doing and how it is regulating the creation of these microvilli.”

Lombardo joined the Jacobs School faculty in 2024 after taking somewhat of a nontraditional career path to biochemistry. He originally studied imaging in the Department of Physics at SUNY Geneseo in its nuclear physics lab, performing imaging using a linear particle accelerator. He was part of a team that produced a unique camera still being used for fusion research at the University of Rochester’s Laboratory for Laser Energetics.

He then worked on single molecule biophysics for his doctoral degree in molecular physiology and biophysics from the University of Vermont.

“That is where I combined that physics approach and biophysics, that physics imaging approach with biological molecules,” he says.

At Vermont, he studied the cytoskeletal protein actin, and the class of proteins called myosins. These are the force-producing molecules in our bodies that produce muscle contraction through an actin-myosin system. These molecules bind to the cytoskeletal structure actin and they produce force and motion using energy.

During a postdoctoral fellowship at Cornell University, Lombardo studied polarity specific to microvilli in actin and myosin.

“That is the trajectory that led to this project. It started in physics and then moved toward how these force-producing motors produce structures. Along the way, I turned into a biochemist,” he says. “The whole time after I left undergrad, I was essentially doing biochemistry, paired with biophysics and cell biology.”

One consistency throughout his entire career path is the high-end state-of-the art imaging that Lombardo has been producing.

“The brand of the lab is to produce the absolute best images that show in the clearest quality the scientific principles that we are looking to investigate,” he says. “We think about imaging as data. We just approach producing an image in a different way. We are not looking to simply take a picture to capture what we see.”

“The image is the data we use, and we analyze that in very complex ways using sophisticated programs that we write ourselves.”

Lombardo’s lab features a custom-built spinning disk confocal microscope.

“I picked every component very carefully. I did not just go to one company and buy what they had,” he says. “Coming from the background that I have, I chose this camera with these other components from several different companies, combined into one custom microscope. It is different than anything else in Western New York. This is what we produce all our images with.”

The light path passes through a literal spinning disk, which has pinholes that pass the laser light through it, illuminating the sample in a controlled manner.

“Instead of illuminating the entire sample all at once, we illuminate little bits of it sequentially. That allows for us to do confocal imaging very quickly,” Lombardo says. “The confocal literally creates a conical light path and that gives us certain imaging advantages, one of which is we can section in the z dimension.”

If you have a sheet of paper, you have a rectangle that would be the x and y dimension. If that were sitting on a table, above and below the table would be the z dimension, Lombardo explains.

“It turns out that all living things exist in three dimensions. When you are talking about polarity, that third dimension matters a lot, because we are talking about what is on one side of the cell versus another,” he says. “We use these imaging approaches to characterize the three-dimensional structure of our samples, and we use the spinning disk so that we can do it very quickly in a way that is conducive to imaging living things.”

Emma Claire Murray, a trainee in the doctoral program in biochemistry, used the lab’s microscope to capture a stunning image of human epithelial cells that ultimately won first place in the Precision and Detail category of the UB Graduate School’s 2025 Art of Research competition.

“I was doing a simple experiment. I was trying to locate the difference between the junctions of mutated epithelial cells and non-mutated epithelial cells. The non-mutated one is the image that I submitted because, when I first saw it, I just thought it looked fantastic,” she says. “I submitted it in the Precision and Detail category because it shows varying cell shapes.”

“The microscope is probably my favorite part of the lab. It is a lot of fun to use, and I have learned a lot on it,” Murray adds. “It is great to see the cells in much finer detail. That is something I think is exciting.”

The winning images in the Art of Research competition were on display at the Buffalo Museum of Science for the month of May.

“We didn’t set out to produce an image that would win at an art competition. That is just the data that we like to collect,” Lombardo says. “It just so happens that along the way, trying to create the most pristine images we could, we happened to snag a really beautiful one.”

“It’s not just another pretty picture though. We intend to use that data; it has scientific value.”