I apologize for the delay in posting this but I am proud to announce a new first author paper out for me. Along with Dooyoung Lee and Dan Hammer, I probed the effect of surface densities of different ligand types on the resulting motion of CD4+ T cells. It was published in Cell and Biomolecular Engineering. A more in depth overview of the article can be found here.
An Experimentally Determined State Diagram for Human CD4+ T Lymphocyte CXCR4-Stimulated Adhesion Under Shear Flow
This is a first author paper of mine where, along with Dooyoung Lee and Dan Hammer, I studied how the relative densities of E-selectin and ICAM-1 affect the different steps of the leukocyte adhesion cascade. This cascade canonically consists of tethering, rolling, firm arrest, and transmigration. Using a recombinant protein surface, we could observe the first three steps in a highly controlled environment with specified densities. Thus, we could experimentally probe predictions made previously in the Hammer lab regarding synergy between selectins and adhesion molecules. In this case, we saw that optimal levels of firm arrest occurred on surfaces containing equimolar amounts of E-selectin and ICAM-1 or surfaces containing a 10X molar excess of ICAM-1. However, these surfaces required a certain level of ligand density (O(10^2) sites/µm^2), below which cells were unable to roll or arrest on the surface. Surfaces containing only one of the ligands were much less efficient at recruiting cells from the free stream compared to surfaces with both E-selectin and ICAM-1. Finally, we also showed almost no change in rolling velocity or time to stop on any of the surfaces, suggesting that the T cells control this aspect of the adhesion cascade independently of the adhesive surface.
Read this article on SpringerLink!
DOI: 10.1007/s12195-018-0519-x
New paper published!
I am excited to announce that my paper with Alex Buffone and Dan Hammer has been accepted for publication at the Journal of Cell Science. It’s about the response of HSPCs to shear flow. You can see a short summary of the paper here.
Migration against the direction of flow is LFA-1 dependent in human hematopoietic stem and progenitor cells
This study is a continuation and extension of my previously published work with Dominguez and Hammer showing a similar phenomena of migration against the direction of fluid flow. However, instead of T lymphocytes, the cells in this manuscript are hematopoietic stem and progenitor cells, which are a more primitive immune cell type. These results show that possibly many immune cells show a similar behavior, which increases the likelihood that this behavior is serving an important biological purpose.
2017 CBE GSS
On September 15, I had the great pleasure of presenting some of my work at the 2017 Penn CBE Graduate Student Symposium (GSS). This symposium is a chance for grad students like myself to present to and network with representatives from industry as well as our fellow students. I was lucky enough to present both a talk and a poster this year. I greatly enjoyed speaking to everyone there and got a lot of great questions regarding my work. Unfortunately, I can’t post the work quite yet, as it is still in the process of being published. However, once the paper is accepted, I’ll make sure to update the site with that information under the appropriate areas. If I didn’t get a chance to see you this year, I hope to see you around in 2018 (assuming I’m still around)!
Update (5/17/2018): As mentioned in the new blog post for today, this work has been published in Cellular and Molecular Bioengineering and can be read about here.
2017 CBE GSS Seminar
This is a short presentation about my work which was eventually published in Cellular and Molecular Bioengineering, initially presented at the 2017 Chemical and Biomolecular Engineering Graduate Student Symposium. The attached file is a PDF, so the movies embedded in the original Powerpoint do not work. However, I am happy to share the presentation if you contact me directly.
4th Year Lunch Seminar
Every year, the 4th year students in the University of Pennsylvania give a lunchtime seminar about their research. This is a link to my presentation. It consists of my published work on T cell migration in response to shear flow (available here), as well as material that is currently under study. This PDF has material which has not been published blacked out. Once the manuscript has been published, I will upload the presentation with the blackout removed.
The direction of migration of T-lymphocytes under flow depends upon which adhesion receptors are engaged
Published in: Integrative Biology (2015)
This study shows that activated T cells use the direction of flow and the identity of the adhesive ligand to determine in which direction the cell should migrate. On VCAM-1-functionalized surfaces, T cells migrate with the direction of flow, while they migrate upstream on ICAM-1-functionalized surfaces. In addition, we showed that this directionality is mediated by the beta-2 integrin of LFA-1.
Supplemented αMEM/F12-based medium enables the survival and growth of primary ovarian follicles encapsulated in alginate hydrogels
Published in: Biotechnology and Bioengineering (2013)
This work is the first reported instance of a serum-free, defined formulation media for the in vitro culture of ovarian follicles. We show that this media allows for the growth of even primary follicles, which is difficult even for traditional system. Thus this system allows for the study of important factors in the maturation of ovarian follicles in a systematic way.
Nicholas R. Anderson 