When we think about the great research and scientific breakthroughs that come out of Johns Hopkins, we often focus on the principal investigators and members of their labs. But there is another very strong force of progress at Johns Hopkins that flies under the radar — the core facilities. Johns Hopkins boasts a large array of core facilities that house instruments for shared use among the university’s labs, but beyond simply supplying these amazing instruments, the cores have something more to offer. The employees who run these cores and instruments are truly a force to be reckoned with.

Core facilities at Johns Hopkins provide some of the most expensive equipment that individual labs often cannot afford to buy and maintain, including high-powered microscopes, flow cytometers, mass spectrometers and deep sequencers, among many others. The people who run the cores and the individual instruments are experts in the optimal use of each piece of equipment and are trained to provide the best and most reliable data. In addition to knowing everything there is to know about a given instrument, the core facility staff members also interact with and help guide the experimental set up of researchers from diverse fields who have highly diverse scientific goals. These core facility workers are often behind-the-scenes miracle workers who play a key role in the success of research projects.

Meet the Unsung Core Heroes

Designing a flow cytometry experiment to isolate and analyze cell populations is no easy task. Flow cytometry is a method that relies on an expensive piece of equipment—a cytometer—to analyze individual cells by suspending them in a fast-moving stream of liquid and capturing information about their size, color and shape with the machine’s detector system. Cells can be “stained” with a nearly infinite array of commercially available dyes or fluorescent molecules, such as those that recognize a certain surface molecule or that differentiate live and dead cells.  The cytometer can be set up to analyze each cell for a specific color or fluorescent wavelength, allowing it to report back the number it counted in each population. Specific populations can then be “sorted,” during which individual cells are shot into a tube sitting underneath the machine to separate out important or interesting cell types for an experiment.

Before starting a flow cytometry experiment, the researcher must decide what fluorophores to use to differentiate one population of cells from another. To add further complication, certain types of cells—for example, immune cells such as monocytes and macrophages—characteristically display high levels of autofluorescence, meaning they have a background level of the color you may be trying to analyze. Dr. Hao Zhang, of one of the flow cytometry cores on campus, is an expert in optimizing fluorophore use for great results and avoiding autofluorescence interference. In a recent collaboration with Dr. Robert Siliciano’s lab, Dr. Zhang performed critical experiments for a study focused on understanding and eliminating cells latently infected with HIV. He sorted cells from human patients for engraftment into mice, which would serve as a humanized-mouse model for the study. This work led to a paper in one of the most high-impact journals: Nature.

Another unsung core hero is Chris Thoburn of the immune monitoring core. Among other things, Thoburn runs cytokine identification assays. Cytokines are important signaling molecules secreted by immune cells as a means of communication. He knows all the ins and outs of how to optimize tissue or cell culture supernatant collection to detect and identify these immunomodulatory molecules, as well as knowing everything there is to know about the assay itself and the instrument used to read the results. He recently helped Dr. Rhoel Dinglasan’s lab perform these assays to identify cytokines secreted by Kupffer cells in response to a parasite. When initial cytokine levels were very low, he suggested ways to optimize the collection step to provide more readable results. Additionally, he played a vital role in acquiring and analyzing all the cytokine data for the study. This work resulted in a submitted manuscript that is currently under review.

Dr. Hao Zhang and Chris Thoburn represent just two examples of these phenomenal core team members. While we may not often hear about the great research that happens in the core facilities, their staff members are undoubtedly scientific wizards with amazing skills. Their ability to take the experimental ideas of so many different people and produce meaningful results is truly a wonder. So, the next time you see a core manager, be sure to give him or her a big thank you from the research community.


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