Biology Reference
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Figure 13.3. Depolarization of mitochondria in U1 cells after treatment with valinomycin (VAL).
Numbers indicate the percentage of cells with depolarized mitochondria, present in the lower right
part of the panels.
can be detected using the ®lters commonly mounted in ¯ow cytometers or
confocal microscopes, so that green emission can be analyzed in ¯uorescence
channel 1 ( FL1) and greenish orange emission in channel 2 ( FL2). JC-1 is
mostly qualitative, considering the shift from green to orange ¯uorescence
emission and vice versa, but can also give quantitative information on mi-
tochondrial massÐeven if less precise than those provided by probes such as
MitoTracker Green, or nonyl acridine orange at low dosesÐconsidering the
pure ¯uorescence intensity, which can be detected in both FL1 and FL2 chan-
nels. Figure 13.3 shows the basic ¯uorescent changes of the probe after loading
of the HIV-1-infected cell line U1 (derived from the myelomonocytic clone
U937, cultured in the presence of the virus ( Folks et al., 1987, 1988)) with JC-1,
and its treatment with the depolarizing agent valinomycin. The behavior of
such cells is absolutely similar to that of the parental cell line U937 (Salvioli
et al., 2000a), indicating that, in this HIV-infected line, mitochondria respond
in the same manner to depolarizing agents.
STUDIES ON MITOCHONDRIA IN HIV-1 INFECTED CELLS
In the past few years, we have studied the behavior of mitochondria during
apoptosis in a variety of experimental models (Cossarizza, 2000; Cossarizza
et al., 1994, 1995a, 1995b, 1999; Troiano et al., 1998; Tropea et al., 1995), as
well as during acute HIV infection. In the ®rst study, we analyzed the presence
of Dc alterations and the propensity to undergo apoptosis in peripheral blood
lymphocytes from subjects with acute HIV syndrome, and evaluated whether
antioxidant drugs that can be used in therapy, such as N-acetyl-cysteine ( NAC),
nicotinamide ( NAM), or l-acetyl-carnitine ( LAC) were able to reduce the
