Sugar-coating our way to genetically modified mesenchymal stem cells: Glycocalyx-inspired cell culture substrates that prime mesenchymal stem cells for polycation-mediated pDNA delivery. - PROJECT SUMMARY
The candidate Caitlyn Castellion is a first-year student who is just beginning her research career. Ms. Castellion
wants to earn a PhD, become a tenure-track faculty member at a research institution, and remedy the lack of
representation of Hispanic women in biochemistry. The diversity supplement will provide her with a solid foun-
dation to chase these career goals. The goal is to equip Ms. Castellion with technical skills, oral, and written
presentation skills through mentoring experiences tailored around her life experiences, unique strengths as a
scientist and career goals. The research plan detailed earlier intentionally exposes Ms. Castellion to both the
synthetic chemistry, lithography, as well as cell/molecular biology aspects of the proposal, which will hopefully
help her refine her research interests by balancing depth and breadth of research experiences. The PI will work
closely with Ms. Castellion at the bench so that she develops expertise in polymer brush synthesis, surface
characterization, mammalian cell culture, cellular assays for polymer-mediated pDNA delivery, and proteomics.
Ms. Castellion will be encouraged to present every month at the lab group meeting, in addition to weekly meet-
ings with the PI and coI to identify roadblocks and workarounds. In addition to the PI, Ms. Castellion will be
informally advised and supported by NSF GRF Jesssica Lawson and a postdoctoral scholar Dr. Ram Prasad
Sekar. Faculty members (Dr. Krishna and Dr. Moyers) will act as academic mentors who will join the PI in advising
Ms. Castellion on non-technical aspects of her career development plan.
The candidate will work on a research direction that is both complementary to and distinct from the original
research plan. This will allow her to benefit from the expertise of the Kumar lab while still forging her own inde-
pendent path. Importantly, the data that she will generate will either generate publications that are independent
of publications resulting from the original research plan. Specifically, she will investigate the role of nanocluster-
ing GAG-mimetic ligands by varying the spatial distribution of polymer brushes. Spatial distribution of polymer
brushes was not proposed in the original research plan due to time and budget constraints. The candidate will
test the following hypothesis: the distances between GAG-mimetic ligands (unsulfated or sulfated glycan resi-
dues) will dictate the proximity of receptor clusters on hMSCs and consequently promote hMSC self-renewal.
We predict that hMSC self-renewal will exhibit a non-monotonic dependence on ligand spacing, with neither
large nor small ligand spacings promoting hMSC proliferation. Rather, ligand spacings that match the inter-re-
ceptor distances on hMSCs will perform best as cell culture substrates, providing an additional level of control
(apart from polymer brush composition and thickness) to augment hMSC self-renewal. After characterizing the
effects of ligand spacing on hMSC self-renewal, the candidate will prime hMSCs on nanopatterned GAG-mimetic
brushes that promoted receptor clustering and self-renewal and test whether polycation-mediated pDNA delivery
is more efficient when hMSCS are primed on nanopatterned substrates with optimized ligand spacings.
