Victor Ma Receives Predoctoral to Postdoctoral Fellow Transition Award

Victor Ma, a fourth-year graduate student in the lab of Dr. Khalid Salaita, was recently selected as one of twenty-six Predoctoroal to Postdoctoral Fellow Transition Award Fellows from the National Institute of Health. This award will provide Victor with two years of funding to complete his doctoral thesis and an additional four years of funding for future postdoc training. In the Salaita lab, with co-mentorship by Dr. Brian Evavold, Victor’s research focuses on developing technologies to study mechanobiology at the molecular scale. With an ultimate goal of establishing an alternative mechanism for regulating T cell activity, he studies the roles of mechanical forces in T cell activation, whether these forces are coordinately controlled by mechano-sensitive proteins, and the importance of these forces for T cell biological function. The findings from these studies can provide insight into a potential strategy for developing effective immunotherapies.

In his postdoc, Victor plans on transitioning into the field of tumor immunology, where he hopes to capitalize on his skillset to elucidate the physical mechanisms responsible for preventing T cells from interacting with tumor cells. “My ultimate career goal is to become an independent investigator at a research-intensive university, where I can assume teaching duties and direct a research lab that combines knowledge from various disciplines to innovate career research,” says Victor. “This award will surely serve as a stepping stone to help achieve my goal!”

Congratulations, Victor!

Congratulations, Dr. Eric Andreansky!

Eric Andreansky successfully defended his dissertation, “Synthetic Studies Toward Methanoquinolizidine-Containing Akuammiline Alkaloids ” on Wednesday, April 26th, 2017. Eric’s committee was led by Simon Blakey with Frank McDonald and Lanny Liebeskind as additional members.

Eric was a Laney Graduate School Woodruff Scholar. He was also a service instructor for the Emory NMR Research Center and interned for a year with the Emory Office of Technology Transfer. Eric was also a member of the first Broadening Experiences in Scientific Training (BEST) cohort, a National Institute of Health-funded graduate training program run jointly with Emory and the Georgia Institute of Technology.

Eric plans to pursue a career in patent law.

Congratulations, Eric!

Research Spotlight: Chen Liang Shines Light on Amyloid’s Shape-Shifting Properties

By: Chen Liang (Lynn Group)

The hallmark of Alzheimer’s disease is the presence of plaques in the brain formed by the aggregation of Aβ peptide with heavy β-sheet content–also known as amyloid. Amyloid is hypothesized to be causative in Alzheimer’s disease through multiple mechanisms such as oxidative stress, interaction with receptors and synaptic loss. Currently, over five million Americans are living with Alzheimer’s disease, costing the nation 236 billion a year. It’s expected that by 2050,healthcare spending on Alzheimer’s will reach one trillion. The NIH invests around 500 million annually for Alzheimer’s research. Despite the prevalence of Alzheimer’s and the intensive efforts of researchers, no effective therapeutics for the disease is yet available. This dilemma attracted me to the study of amyloid as my PhD research project.

Current drug design for Alzheimer’s disease focuses on finding molecules that bind and block the action of these deleterious proteins. Typically, a disease—like cancer, diabetes, and, as some have believed, Alzheimer’s—is caused by proteins with a fixed structure. However, my study in Dr. David Lynn’s lab at Emory University demonstrates that amyloid, unlike conventional drug targets, is highly dynamic and can change structure over time. My research could potentially explain why conventional drug discovery methods don’t succeed with Alzheimer’s –they generally ignore the structural diversity and the changing nature of amyloid.

The peptide I use in this research is the nucleating core of Aβ Dutch mutant, Aβ(16-22)E22Q or KLVFFAQ. People with this genetic mutation develop a more severe form of Alzheimer’s. I discovered that early on, after dissolving, this peptide forms ribbon shaped structures and later autocatalytically change into fibers (Figure 1). More detailed characterization using IE-IR (isotope edited infrared spectroscopy) and solid state NMR (Nuclear Magnetic Resonance) reveals that in the ribbon shape, two neighboring peptides within a β-sheet are pointing in the opposite direction—a state that is commonly referred to as an anti-parallel β-sheet arrangement. Yet the conformation is transient. After a week, the peptides autocatalytically switch into parallel β-sheet where all peptides are pointing in the same direction. Furthermore, by simply adding salt, I was able to control the speed of such shape shifting and even greatly expand the range of observed structures.

Figure 1. Amyloid could change shape during assembly. E22Q initially forms anti-parallel ribbons (left) and later automatically changes into parallel fibers(right). Scale bar 200nm
Figure 1. Amyloid could change shape during assembly. E22Q initially forms anti-parallel ribbons (left) and later automatically changes into parallel fibers (right). Scale bar 200nm. Reprinted (adapted) with permission from Chen Liang et al. “Kinetic Intermediates in Amyloid Assembly.” J. Am. Chem. Soc., 2014, 136 (43), pp 15146-15149. Copyright 2016 American Chemical Society.

This research is significant in the study of Alzheimer’s disease and drug development because it begins to explain why no effective therapeutics have been developed for Alzheimer’s disease. Due to the high thermo-stability of amyloid, researchers commonly assume amyloid structure remains static upon assembly. My study demonstrates the opposite: amyloid can change structure and such a change is sensitive to environmental conditions. Now people can imagine the change and diversity that could occur when amyloid is spreading through different cellular environments as it ravages the brain.

Such an “environmental dependent conformational change” is an important property of Aβ protein and these dynamics are beginning to gain more attention in the scientific community despite being counter-intuitive. Amyloid’s high thermostability has led researchers to reason that once formed amyloid should be stable and their structure should be faithfully replicated throughout the brain. The implication of my study on the treatment of Alzheimer is that instead of measuring the amount of amyloid and treating patients non-discriminately, the structure diversity of amyloids should be central to any consideration in developing diagnostics and therapeutics. New methods of drug discovery—taking into account amyloid’s unique properties—will certainly be necessary for treating Alzheimer’s and the increasing number of amyloid diseases.

Further Reading:

Chen Liang et al. “Kinetic Intermediates in Amyloid Assembly.” J. Am. Chem. Soc., 2014, 136 (43), pp 15146-15149. Copyright 2016 American Chemical Society.