Carl A. Gruetter, Ph.D.

Carl A. Gruetter, Ph.D.Professor
Department of Pharmacology, Physiology and Toxicology
Research Cluster: Cardiovascular Disease, Obesity, and Diabetes
Office: MEB 132
Phone: (304) 696-7316 | Fax: (304) 696-7391
E-mail: gruetter@marshall.edu

Research Interests

  1. Role of Intracellular Histamine in Cancer. Our current research is testing the novel hypothesis that endogenous intracellular histamine regulates invasiveness of cancer cells.  Consistent with some previous evidence of increased amounts of endogenous histamine in some other cancer cells, we have recently demonstrated that the histamine level in malignant melanoma cells is more than 200-fold higher than in their counterpart non-cancerous melanocytes (Davis, et al., Inflamm. Res. 2010 Jul 18. [Epub ahead of print]). To evaluate the potential role of histamine in regulating invasiveness of cancer cells, experiments will be conducted to determine the effects of reduced endogenous histamine levels on the ability of the cultured melanoma cells to invade a substrate which models a normal extracellular environment. The endogenous histamine content of the melanoma cells will be reduced by inhibiting expression of the histamine forming enzyme, histidine decarboxylase (HDC), within the melanoma cells. HDC expression will be inhibited through shRNA transfection to inhibit the HDC gene.  Inhibition of the HDC expression will be verified by Western blot analysis and/or real-time RT-PCR.  Reduced levels of histamine in the transfected cells will be verified by measuring histamine content using enzymeimmunoassay. It is expected that the results from this research will establish the existence of a novel pathway of cell regulation within melanoma cells and lay the foundation for more comprehensive investigation of the role of endogenous histamine production in the development and progression of melanoma and provide new approaches for the treatment of melanoma and other cancers. 
  2. Role of histamine in vascular smooth muscle cells. Although long-known to be present in blood vessels, non-mast cell histamine has received little investigation over the years as a potential factor involved in regulation of the vascular system. In view of extensive evidence suggesting multiple important roles for histamine in vascular physiology and pathophysiology, the goal of this project is to determine the function of the endogenous histaminergic system in vascular cells. Currently, research is aimed at elucidating regulatory mechanisms of histamine synthesis/metabolism and the function of histamine and/or its metabolites in vascular smooth muscle and endothelial cells. This research involves: 1) immunocytochemistry, Western blot and qualitative and quantitative PCR to investigate regulation of expression of histamine synthetic and metabolic enzymes; 2) enzyme activity measurements to assess post-translational regulation of the histamine synthetic and metabolic enzymes; 3) enzyme activity measurements to assess the capacity of histamine and/or its metabolites to interact with and regulate heme-containing enzymes; 4) manipulation of histamine synthesis/metabolism and measurement of appropriate cellular responses to determine potential roles(s) of histamine and/or its metabolites to regulate cell function. Results from this research should establish a basic role for the endogenous histaminergic system in the regulation of vascular cell function and provide the groundwork for future studies aimed at determining its involvement in cardiovascular diseases.

Selected Publications

Davis SC, Clark S, Hayes JR, Green TL, Gruetter CA,  Up-regulation of histidine decarboxylase expression and histamine content in B16F10 murine melanoma cells. Inflamm Res. 60:55-61, 2011.  [Epub 2010 Jul 18, 2010.]

Tippens AS, Davis SV, Hayes JR, Bryda EC, Green TL, Gruetter CA. Detection of histidine decarboxylase in rat aorta and cultured rat aortic smooth muscle cells. Inflamm Res 53:390-395, 2004. Epub Aug 10, 2004

Tippens AS, Gruetter CA. Detection of histidine decarboxylase mRNA in human vascular smooth muscle and endothelial cells. Inflamm Res. 53:215-216, 2004. Epub May 12, 2004.

Gruetter CA, Bailey B, Easterling L, Szarek JL. A23187 induces release of histamine from isolated rat aorta. Life Sci 70:1709-1717, 2002.

Gruetter CA, Lemke SM, Valentovic MA, Szarek JL. Evidence that histamine is involved as a mediator of endothelium-dependent contraction induced by A23187 in bovine intrapulmonary vein. Eur J Pharmacol 257:275-283, 1994.