University of Florida

Corwin Nelson, Ph.D.

Infectious diseases in livestock result in substantial production losses in the livestock industry and threaten food safety and security.  The overall goal of my research is to minimize the impact of infectious diseases in livestock through understanding how genetic and environmental factors influence the immune system.  My research concentrates on the influence and regulation of vitamin D signaling in the immune system with an emphasis on mastitis in dairy cattle.  The vitamin D pathway is activated in bovine macrophages in response to toll-like receptor recognition of pathogen associated molecular patterns.  In this pathway 25-hydroxyvitamin D3 is converted to the active vitamin D hormone, 1,25-dihydroxyvitamin D3, by the 1α-25-hydroxyvitamin D hydroxylase (1α-OHase/CYP27B1).  The 1,25-dihydroxyvitamin D3 produced in the bovine macrophage in an intracrine manner to induce expression of immunologically important genes such as iNOS and RANTES, and in a paracrine manner to suppress inflammatory T lymphocytes.  A similar pathway exists in the human macrophage that acts to enhance macrophage antimicrobial activity.  Notably, studies with an experimental model of mastitis in dairy cattle have revealed that the vitamin D pathway is activated in the udder in response to bacterial infection and ultimately functions to improve resistance to bacterial infection.

The presence of a vitamin D signaling mechanism in the immune system has profound implications for animal and human health and beckons the need for further investigation.  First instance, the presence of the vitamin D pathway in the immune system suggests that 25-hydroxyvitamin D3 availability, which is primarily influenced by sun exposure and dietary vitamin D, influences immune function.  This hypothesis is supported by epidemiological evidence that vitamin D status of humans is inversely correlated with risk of autoimmune and infectious diseases (i.e. multiple sclerosis, type 1 diabetes, and tuberculosis). Vitamin D requirements for proper immune function of livestock or humans, however, have not been established.  A second implication is that the ability of the vitamin D hormone to suppress inflammation and improve host defense allows the potential for alternative preventative and therapeutic strategies.  The influence of the vitamin D pathway on immunity and how it is regulated, however, is only partially understood which limits efforts to support immunity through the vitamin D pathway.  Therefore, primary efforts of my research are to 1) identify targets of the vitamin D hormone and the physiological significance of those targets in the immune system, and 2) identify the genetic, epigenetic and environmental (i.e. nutritional and pathogen) influences on vitamin D metabolism and the molecular basis of those influences.  This research is carried out using molecular and physiological approaches primarily in cattle with an emphasis on addressing the issue of mastitis in dairy cattle. This research ultimately serves to benefit the livestock industry, ensure adequate food supply, and advance human health through increasing basic knowledge of animal physiology.

Representative Publications:
Nelson, C.D., Reihardt, T.A., Lippolis, J.D., Sacco, R.A., and B.J. Nonnecke. 2012. Vitamin D signaling in the bovine immune system: A model for understanding human vitamin D requirements.  Nutrients. 4(3), 181-196.

Hayes, C.E., Nelson, C.D., and J.A. Spanier. 2013. “Vitamin D and Autoimmune Disease”, Vitamin D: Oxidative Stress, Immunity, and Aging, A. Gombart, Editor. CRC Press, Boca Raton, FL.

Hayes, C.E., Nashold, F.E., Mayne, C.G., Spanier, J.A., and C.D. Nelson. 2011. "Vitamin D and Multiple Sclerosis", Vitamin D, Third Edition, D. Feldman, J. Pike and J. Adams, Editors. Elsevier, San Diego, CA.

Lippolis, J.D., Reinhardt, T.A., Sacco, R.A., Nonnecke, B.J., and C.D. Nelson. 2011. Treatment of an intramammary bacterial infection with 25-hydroxyvitamin d(3). PLoS One, 6, e25479.

Nelson, C.D., Nonnecke, B.J., Reinhardt, T.A., Waters, W.R., Beitz, D.C., and J.D. Lippolis. 2011. Regulation of Mycobacterium-specific mononuclear cell responses by 25-hydroxyvitamin D3. PLoS ONE. 6, e21674.

Nelson, C.D., Reinhardt, T.A., Beitz, D.C., and J.D. Lippolis. 2010. In vivo activation of the intracrine vitamin D pathway in innate immune cells and mammary tissue during a bacterial infection. PLoS ONE. 5, e15469.

Nelson, C.D., Reinhardt, T.A., Thacker, T.C., Beitz, D.C., and J.D. Lippolis. 2010. Modulation of the bovine innate immune response by production of 1alpha,25-dihydroxyvitamin D(3) in bovine monocytes. J. Dairy. Sci. 93, 1041-1049.

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Corwin Nelson, Ph.D.
Assistant Professor
Department of Animal Sciences
Ph.D., Biochemistry and Immunobiology, Iowa State University
Postdoc., Department of Biochemistry, University of Wisconsin-Madison

Department of Animal Sciences: Faculty Page