Dr. Nichols received his B.S. degree from Lindenwood College and Ph.D. from Purdue University. Prior to joining the UM-St. Louis faculty in Fall 2004, he completed a postdoctoral fellowship at the Mayo Clinic in Jacksonville, FL.
Protein assembly or aggregation is widely recognized as a significant contributing factor to a number of neurodegenerative diseases including Alzheimer's disease (AD), Parkinson's disease, Huntington's disease, and others. Remarkably, the proteins or peptides implicated in these diseases, while possessing different amino acid sequences, all self-assemble to form similar fibrillar structures termed amyloid. One such peptide is amyloid-β (Aβ), a 40-42-residue peptide and the primary component of the senile plaques found in AD brains. The leading hypothesis in AD research maintains that accumulation of aggregated Aβ is the primary cause of the disease.
One research area in my laboratory involves mechanistic studies of Aβ aggregation. Objectives include isolation and characterization of aggregation intermediates and investigation of conditions that influence aggregation.These studies utilize an array of biophysical techniques to probe mechanistic and structural questions.
The other major research thrust in my laboratory addresses the question of how Aβ aggregates are detrimental to cells.One hypothesis is induction of a sustained inflammatory response causing the release of harmful cytokines such as tumor necrosis factor-α interleukin-1-β.We are studying these effects in monocyte/macrophage cells and smooth muscle cells with the goal of understanding the cause of the inflammatory response, how it relates to cell toxicity, and identification of novel ways to regulate cytokine release.
(Left) Electron microscopy image (59k magnification) of isolated Aβ42 protofibrils. (Right) Binding of Aβ42 protofibrils (green) tp BV-2 microglia. Cell nuclei are shown in blue.
“CD47 does not mediate amyloid-β(1-42) protofibril-stimulated microglial cytokine release,” S. Karki and M.R. Nichols, Biochem Biophys Res Commun, 2014, in press
“Amyloid-β(1-42) protofibrils stimulate a quantum of secreted IL-1β despite significant intracellular IL-1β accumulation in microglia,” S.E. Terrill-Usery, M.J. Mohan, and M.R. Nichols, BBA-Mol Bas Dis, 2014, 1842, 2276
“The influence of gold surface texture on microglia morphology and activation,” Y.H. Tan, S.E. Terrill, G.S. Paranjape, K.J. Stine, and Nichols, M.R., Biomater Sci, 2014, 2, 110
"The influence of gold surface texture on microglia morphology and activation," Y. H. Tan, S. Terrill, G. S. Paranjape, K. J. Stine and M. R. Nichols, Biomat. Sci. 2014, 2, 110.
"Stability of early-stage amyloid-β(1-42) aggregation species,” K. A.Coalier, G. S. Paranjape, S. Karki, and M. R. Nichols, Biochimica et Biophysica Acta, 2013, 1834, 65
“Amyloid-β(1-42) protofibrils formed in modified artificial cerebrospinal fluid bind and activate microglia,” G .S. Paranjape, S. E. Terrill, L. K. Gouwens, B. M. Ruck, and M. R. Nichols, J Neuroimmun Pharmacol, 2013, 8, 312
“A comparative first-principles study of structural and electronic properties among memantine, amantadine and rimantadine,” K. Middleton, G.P. Zhang, M.R. Nichols, and T.F. George, Mol Physics, 2012, 110, 685
“Isolated amyloid-β(1-42) protofibrils, but not isolated fibrils, are robust stimulators of microglia,” G.S. Paranjape, L.K. Gouwens, D.C. Osborn, and M.R. Nichols, ACS Chem Neurosci, 2012, 3, 302.
“Substituted tryptophans at amyloid-β(1-40) residues 19 and 20 experience different environments after fibril formation,” R. T. McDonough, G. Paranjape, F. Gallazi, and M. R. Nichols, Arch. Biochem. Biophys. 2011, 514, 27
“Development of LPS antagonistic therapeutics: synthesis and evaluation of glucopyranoside-spacer-amino acid motifs,” S. Kaeothip, G. Paranjape, S. E. Terrill, A. F. G. Bongat, M. L. D. Udan, T. Kamkhachorn, H. L. Johnson, M. R. Nichols and A. V. Demchenko, RSC Advances, 2011, 1, 83.
"Probing the amyloid-β(1-40) fibril environment with substituted tryptophan residues," J. C. Touchette, L. L. Williams, D. Ajit, F. Gallazi, and M. R. Nichols Arch Biochem Biophys, 2010, 494, 192.
"Amyloid-β(1-42) fibrillar precursors are optimal for inducing tumor necrosis factor-α production in the THP-1 human monocytic cell line,” D. Ajit, M. L. D. Udan, G. Paranjape, and M.R. Nichols, Biochemistry, 2009, 48, 10011.
"Oligomeric amyloid-β(1-42) induces THP-1 human monocyte adhesion and maturation,” N. R. Crouse, D. Ajit, M. L. D. Udan, and M. R. Nichols, Brain Res, 2009,1254, 109
"Toll-like receptors 2 and 4 mediate Aβ(1-42) activation of the innate immune response in a human monocytic cell line,” M. L. D. Udan, D. Ajit, N. R. Crouse, and M .R. Nichols, J Neurochem, 2008, 104, 524
"Amyloid-β aggregates formed at nonpolar interfaces differ from amyloid-ß protofibrils produced in aqueous buffers,” M. R. Nichols, M. A. Moss, D. K. Reed, J. H. Hoh, and T .L. Rosenberry, Microsc Res Tech, 2005, 67, 164