Nam and Na prevent NAD⁺ shortage and cell death induced by FK866 in human T lymphocytes.

<p>A, PHA-stimulated PBLs were treated (or not) with 33 nM FK866 in the presence or absence of 10 mM Nam or of 10 µM Na. After 48 h, NAD⁺ content was determined (expressed as percentage of NAD⁺ content in FK866-untreated cells). B, PBLs were cultured for 24 h with or without PHA, 1 µg/ml Con A, or 50 ng/ml PMA and 0.5 µM ionomycin. Thereafter, Naprt1 mRNA levels were detected by Q-PCR. mRNA levels in mitogen-stimulated PBLs were compared to those in unstimulated PBLs. C, D, PHA-stimulated PBLs were incubated for five days with or without 10 mM Nam or 10 µM Na in the presence or absence of the indicated FK866 concentrations. Thereafter, cells were imaged by light microscopy (C), and cell viability was determined (D). E, PHA-stimulated PBLs were incubated for five days with or without 33 nM Fk866 in the presence of the indicated concentrations of Nam, Na, or tryptophan (Trp). Viability was subsequently determined. F, PBLs were stimulated with or without PHA in the presence or absence of 1 mM Nam or Na. Thymidine incorporation was measured after 48 h by a 16-h pulse with 0.5 µCi/well [³H]thymidine. D-F each treatment was tested in triplicate wells. Results are means ± SD of three (A, B, F) or four (D, E) experiments. In panel C, one representative experiment out of three is shown.