High-field 19.6T 27Al solid-state MAS NMR of in vitro aluminated brain tissue

• Published in: Journal of magnetic resonance (1997) 2004-10, Vol.170 (2), p.257-262
• Main Authors: Bryant, Pamela L, Lukiw, Walter J, Gan, Zhehong, Hall, Randall W, Butler, Leslie G
• Format: Article
• Language: English
• Subjects: Aluminum - chemistry; Alzheimer Disease - metabolism; Brain Chemistry; Cells, Cultured; Humans; In Vitro Techniques; Magnetic Resonance Spectroscopy - methods; Radioisotopes; Retina - metabolism; RNA - metabolism; Temporal Lobe - metabolism
• ISSN: 1090-7807
• DOI: 10.1016/j.jmr.2003.12.013

The combination of (27)Al high-field solid-state NMR (19.6T) with rapid spinning speeds (17.8 kHz) is used to acquire (27)Al NMR spectra of total RNA human brain temporal lobe tissues exposed to 0.10 mM Al(3+) (as AlCl(3)) and of human retinal pigment epithelial cells (ARPE-19), grown in 0.10 mM AlCl(3). The spectra of these model systems show multiple Al(3+) binding sites, good signal/noise ratios and apparent chemical shift dispersions. A single broad peak (-3 to 11 ppm) is seen for the aluminated ARPE-19 cells, consistent with reported solution-state NMR chemical shifts of Al-transferrin. The aluminated brain tissue has a considerably different (27)Al MAS NMR spectrum. In addition to the transferrin-type resonance, additional peaks are seen. Tentative assignments include: -9 to -3 ppm, octahedral AlO(6) (phosphate and water); 9 ppm, condensed AlO(6) units (Al-O-Al bridges); 24 ppm, tetrahedral AlO(3)N and/or octahedral Al-carbonate; and 35 ppm, more N-substituted aluminum and /or tetrahedral AlO(4). Thus, brain tissue is susceptible to a broad range of coordination by aluminum. Furthermore, the moderate (27)Al C(Q) values (all less than 10 MHz) suggest future NMR studies may be performed at 9.4T and a spin rate of 20 kHz.