Alexandre Mezentsev, Ph.D.

Contact Information

Center for Radiological Research
VC 11-215
630 W. 168th St.
New York, NY 10032

Tel: (212) 305-3911
Fax: (212) 305-3229
email: am2710@columbia.edu

Research Interests

  • Role of epidermis in mediation of postirradiational response

  • Bystander effect in 3-dimensional tissue models

  • Specific signature of ionizing radiation in gene expression

  • Induction of cytokines and eicosanoids in irradiated and bystander cells

    Academic Training  

 

Graduate:

M.Sc. with honor, Moscow State University, Moscow, Russia, 1991

 

 

Ph.D., Russian Academy of Sciences, Moscow, 1996

 


   Current Academic and Professional Appointments  

  • Associate Research Scientist, Center for Radiological Research, College of Physicians & Surgeons of Columbia University Medical Center

   Current Research  

My research in Columbia University is dedicated to the bystander effects in the epidermis induced by ionizing radiation. Particularly, we want to characterize the effects of small doses of irradiation in 3-dimensional skin models. Assuming that each kind of irradiation has own specific signature in the gene expression, we would identify differentially expressed genes and assess their contribution to the development of postirradiational responses. In the future, some of those misregulated genes will be used as biomarkers in diagnostic and assessment of the absorbed dose. Others will serve as potential targets for the newly developed pharmaceutical drugs.

Previously, the scientific community paid significantly more attention to the effects caused by the man-generated radiation. To the time, most of the data were obtained after an acute (short-time) exposure to a relatively high dose of gamma- or x- rays. NASA's plans to send piloted missions to the Moon and Mars raised the question of a potential risk of long-term radiation exposure for the human body. Furthermore, the space irradiation is quite different from one that we deal on the Earth. The cosmic rays have different composition and properties and their effects on the human body remain uncharacterized. This increases an actuality of the research like ours.

On the other hand, the extensive studies of postirradiational effects require an experimental model that would respond adequately to the impact. Unfortunately, the traditional approach employed by cell biologists has all these limitations of culturing the cells in a monolayer. Indeed, many scientists consider the cells as equal and independent units, which is not truth in the tissue. Role of intracellular contacts was often ignored or restricted to the interactions through the medium. In our opinion, it is hard to expect that cell behavior in a T- flask will correspond to one in vivo. Moreover, the prolonged cell culturing compromises the genome stability and promotes an accumulation of chromosome aberrations. My previous work in Biomedical Sciences, which involved multiple experiments with different kind of 3-dimensional tissue models and explants led me to the conclusion that 3-dimensional tissues remain the most adequate model to study processes that occur in the body.

In perspective, our studies will include functional genomic analysis of various aspects of the postirradiational effects, and a comparison of functional genomic responses to different kinds of ionizing radiation. In addition to the list of the specific genes those expression was affected by irradiation we would also identify the most fragile areas in the genome, which more frequently undergo the mutations. We expect that our studies will help us to answer the question whether the existing risk of the cosmic rays prevents us from sending the people to the space with a long- term mission and suggest a strategy to minimize the consequences of space radiation.

   Selected Publications  

Refered Journal articles (15 printed works):

  • Geng S, Mezentsev A, Kalachikov S, Raith K, Roop DR and Panteleyev AA. Targeted ablation of Arnt in mouse epidermis results in profound defects in desquamation and epidermal barrier function. J Cell Sci 119:4901-12, 2006. [abstract]

  • Mezentsev A, Mastyugin V, Seta F, Ashkar S, Kemp R, Reddy DS, Falck JR, Dunn MW and Laniado-Schwartzman M. Transfection of cytochrome P4504B1 into the cornea increases angiogenic activity of the limbal vessels. J Pharmacol Exp Ther 315:42-50, 2005. [abstract]

  • Mezentsev A, Merks RM, O'Riordan E, Chen J, Mendelev N, Goligorsky MS and Brodsky SV. Endothelial microparticles affect angiogenesis in vitro: role of oxidative stress. Am J Physiol Heart Circ Physiol 289:H1106-14, 2005. [abstract]

  • Li Volti G, Sacerdoti D, Sangras B, Vanella A, Mezentsev A, Scapagnini G, Falck JR and Abraham NG. Carbon monoxide signaling in promoting angiogenesis in human microvessel endothelial cells. Antioxid Redox Signal 7:704-10, 2005. [abstract]

  • Mastyugin V, Mezentsev A, Zhang WX, Ashkar S, Dunn MW and Laniado-Schwartzman M. Promoter activity and regulation of the corneal CYP4B1 gene by hypoxia. J Cell Biochem 91:1218-38, 2004. [abstract]

Published Abstracts & Letters (26 posters and oral presentations):

  • Mezentsev A and Amundson SA. Response to low and high doses of proton irradiation in 3-dimensional tissue model Epi-200. The 54th Annual Meeting of The Society for Radiological Research, Boston, 2008.

  • Amundson SA, Brenner DJ and Mezentsev A. Mechanistic and quantitative studies of bystander responses in 3-D tissues for low-dose radiation risk estimation. The 7th Low Dose Radiation Workshop, Washington DC, 2007.

  • Mezentsev A, Kalachikov SM. and Panteleyev AA. Regulation of Epidermal Late- Differentiation Genes via Arnt-dependent Pathway in Primary Mouse Keratinocytes Requires Chromatin Remodeling. Society for Investigative Dermatology Annual Meeting, 2006. J. Invest. Derm. 126, S4, P.69.

  • Mezentsev A, Kalachikov SM. and Panteleyev AA. The Patterns of Periderm Shedding in Mice and the Role of Arnt in Regulation of This Process. Society for Investigative Dermatology Annual Meeting, 2006. J. Invest. Derm. 126, S4, P.69.

  • Geng S., Mezentsev A, Miho I, Kalachikov SM. and Panteleyev AA. The Role of Arnt gene in Perinatal Mouse Skin Neovascularization. Society for Investigative Dermatology Annual Meeting, 2006. J. Invest. Derm. 126, S4, P.4

  • Mezentsev A, Seta F, Kemp R, Dunn MW and Laniado-Schwartzman M. The Corneal epithelial CYP4B1 produces angiogenic eicosanoids and induces inflammation of the ocular surface. ARVO, Program Summary Book, 2005.

Click here for CV and full list of publications

 

Updated 10/28/08

 

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