Jen Martin

The ability of hemoglobin to scavenge the potent vasodilator nitric oxide (NO) in the blood has been well established as a mechanism of vascular tone homeostasis. In endothelial cells, the alpha chain of hemoglobin (hereafter, alpha globin) and endothelial NO synthase form a macromolecular complex, providing a sink for NO directly adjacent to the production source. We have developed an alpha globin mimetic peptide (named HbαX) that displaces endogenous alpha globin and increases bioavailable NO for vasodilation. Here we show that, in vivo, HbαX administration increases capillary oxygenation and blood flow in arterioles acutely and produces a sustained decrease in systolic blood pressure in normal and angiotensin II-induced hypertensive states. HbαX acts with high specificity and affinity to endothelial NO synthase, without toxicity to liver and kidney and no effect on p50 of O2 binding in red blood cells. In human vasculature, HbαX blunts vasoconstrictive response to cumulative doses of phenylephrine, a potent constricting agent. By binding to endothelial NO synthase and displacing endogenous alpha globin, HbαX modulates important metrics of vascular function, increasing vasodilation and flow in the resistance vasculature.

Modulating Vascular Hemodynamics With an Alpha Globin Mimetic Peptide (HbαX).
Keller TC 4th, Butcher JT, Broseghini-Filho GB, Marziano C, DeLalio LJ, Rogers S, Ning B, Martin JN, Chechova S, Cabot M, Shu X, Best AK, Good ME, Simão Padilha A, Purdy M, Yeager M, Peirce SM, Hu S, Doctor A, Barrett E, Le TH, Columbus L, Isakson BE. Hypertension. (6):1494-1503 (2016).

Martin JN, Ball LM, Solomon TL, Dewald AH, Criss AK, Columbus L.Neisserial Opa protein-CEACAM interactions: Competition for receptors as a means of bacterial invasion and pathogenesis. Biochemistry. 55:4286-94 (2016).

Dr. Ashton Brock and Dr. Jennifer Martin

May 2016, Jen and Ashton graduated with their PhD degrees. Ashton started a clinical chemistry postdoctoral position at UVA and Jen is staying in the lab for a year to work with Linda on revising Introductory Chemistry at UVA.img_5908

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Johnson MB, Ball LM, Daily KP, Martin JN, Columbus L and Criss AK. Opa+ Neisseria gonorrhoeae has reduced survival in human neutrophils via Src family kinase-mediated bacterial trafficking into mature phagolysosomes Cellular Microbiology.17:648-665 (2015)

Columbus Lab Members Presents at the 59th Annual Meeting of the Biophysical Society

Four graduate students attended the 2015 Annual Biophysical Society Meeting in Baltimore on Febreuary 7-11.

Jennifer Martin presented a platform talk entitled Insights into the Specificity of Neisserial Opa Protein Interactions with Human Receptors.

Ashton Brock presented a poster entitled Systematic Perturbations of Micelle Properties to Investigate the Stabilization of Membrane Protein Structure and Function.

Marrissa Keiber presented a poster entitled Neisserial Opa Protein Dynamics and Interaction with Host CEACAM Receptors.

Jason Kuhn presented a poster entitled Interactions of Liposomal Opa Proteins with Human Cell Surface CEACAM Receptors.

Postdoctoral Fellow


PhD: Chemistry, University of Virginia (2016)
BS: Biology, Penn State Berks (2011)

Jen’s research aims to compare the binding affinity and selectivity of various Opa proteins with their cognate receptors, both in vivo (expressed on the surface of Neisseria gonhorrhoeae) and in vitro (reconstituted into liposomes). Additionally, she aims to identify the molecular determinants of the interactions between Opa proteins and their receptors in vitro, in order to gain a better understanding of bacterial pathogen – host interactions.

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Jen Presents a Poster at the Protein Transport Across Cell Membranes Gordon Research Conference

Jen presented a poster entitled “Neisseria Opa protein interactions with human receptors in vitro and in vivo” at the Protein Transport Across Cell Membranes Gordon Research Conference in Gavelston Texas on March 9-14, 2014. The poster described her thesis work in collaboration with the Criss laboratory.

Columbus Lab Undergraduates Present at SURC 2014

On Thursday, January 30th, The Columbus Lab undergraduates drove to the University of Tennessee in Knoxville to attend the 46th Southeast Undergraduate Research Conference. Graduate students, Ashton Brock and Jennifer Martin and Linda joined them for the adventure.






Nana Bosomtwe presented a poster entitled Thermophilic Coupling Enzymes: Enabling Functional Studies at Physiological Temperatures and was the recipient of a travel award to the conference.













Elleansar Okwei presented a poster entitled Unraveling Aminotransferase Specificity: The activity of TM1131, TM1698, and TM1255 and received a Best Poster Presentation Award in the Biochemical division.













Tomihiro Ono presented a poster entitled Modulating Micelle Fluidity for Membrane Protein Structural Studies and received a Best Poster Presentation Award in the Physical division.













Sebastein Ortez presented a poster entitled Progress Towards Understanding OpaD Interactions with CEACAM1 and received a Best Poster Presentation Award in the Biochemical division.













Jessica Yoo presented a poster entitled Progress Towards Co-crystallization of the Broad Range Thermoplasma acidophilum nucleoside kinase (TaNK) with Substrates.

Ashton & Jen selected for NIH Funded UVA Training Grants

Ashton received the Molecular Biophysics Training Grant. he Predoctoral Molecular Biophysics Training Program is oriented toward providing a strong biophysics-related training environment that supplements the basic degree requirements and goals of the degree-granting departments within the University of Virginia.

Jen received the Cell and Molecular Biology(CMB)training grant.The Cell and Molecular Biology faculty at the University of Virginia provides a comprehensive graduate training program in modern cell and molecular biological sciences