HIV protease inhibitors provide neuroprotection through inhibition of mitochondrial apoptosis in mice
Toshio Hisatomi, Toru Nakazawa, Kousuke Noda, Lama Almulki, Shinsuke Miyahara, Shintaro Nakao, Yasuhiro Ito, Haicheng She, Riichiro Kohno, Norman Michaud, Tatsuro Ishibashi, Ali Hafezi-Moghadam, Andrew D. Badley, Guido Kroemer, Joan W. Miller
Toshio Hisatomi, Toru Nakazawa, Kousuke Noda, Lama Almulki, Shinsuke Miyahara, Shintaro Nakao, Yasuhiro Ito, Haicheng She, Riichiro Kohno, Norman Michaud, Tatsuro Ishibashi, Ali Hafezi-Moghadam, Andrew D. Badley, Guido Kroemer, Joan W. Miller
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Research Article Neuroscience

HIV protease inhibitors provide neuroprotection through inhibition of mitochondrial apoptosis in mice

Abstract

Neuroprotection can be achieved by preventing apoptotic death of postmitotic cells. Apoptotic death can occur by either a caspase-dependent mechanism, involving cytochrome c, apoptosis protease-activating factor–1 (Apaf-1), and caspase-9, or a caspase-independent mechanism, involving apoptosis-inducing factor (AIF). HIV protease inhibitors (PIs) avert apoptosis in part by preventing mitochondrial outer membrane permeabilization (MOMP), but the precise mechanism by which they work is not known. Here, we evaluated the impact of the PIs in a mouse model of retinal detachment (RD) in vivo and in murine primary retinal cell cultures in vitro. Oral administration of the PIs nelfinavir and ritonavir significantly inhibited photoreceptor apoptosis, while preventing the translocation of AIF from mitochondria to the nucleus as well as the activation of caspase-9. RD-induced photoreceptor apoptosis was similarly inhibited in mice carrying hypomorphic mutations of the genes encoding AIF or Apaf-1. Nelfinavir attenuated apoptosis as well as mitochondrial release of AIF and cytochrome c, and subsequent activation of caspase-9 in vitro, in photoreceptor cultures exposed to starvation or monocyte chemoattractant protein–1–stimulated (MCP-1–stimulated) macrophages. Our results suggest that the MOMP inhibition by PIs involved interruption of both caspase-dependent and caspase-independent apoptosis pathways and that PIs may be clinically useful for the treatment of diseases caused by excessive apoptosis.

Authors

Toshio Hisatomi, Toru Nakazawa, Kousuke Noda, Lama Almulki, Shinsuke Miyahara, Shintaro Nakao, Yasuhiro Ito, Haicheng She, Riichiro Kohno, Norman Michaud, Tatsuro Ishibashi, Ali Hafezi-Moghadam, Andrew D. Badley, Guido Kroemer, Joan W. Miller

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Figure 8

PI increased survival of photoreceptors and preserved mitochondrial potential in vitro in 2 models of primary retinal cell cultures.

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PI increased survival of photoreceptors and preserved mitochondrial pote...
The viability of retinal cells was measured with calcein AM after starvation or after coculture with macrophages (A–E and P; calcein AM in green). Calcein-positive viable cells decreased after starvation (B) or coculture (D) as compared with untreated control (A). PI (NFV, 7 μM) treatment significantly increased calcein-positive cells (C and E). Recoverin+ photoreceptors attaching on culture dish were analyzed after starvation or coculture with macrophages (F–J and Q; recoverin in red, GFP in green, DAPI in blue). Attaching recoverin+ photoreceptors decreased after 24 hours incubation (G and I) as compared with untreated control cultures (F). PI treatment significantly rescued photoreceptors from apoptotic cell death (H and J). Mitochondrial function was assessed by a mitochondrial potential–sensitive dye, CMTMRos. CMTMRos intake (K–O, R; CMTMRos in red, GFP in green, DAPI in blue) was lost after induction of apoptosis (L and N) but reversed in NFV-treated cells (M and O). Representative images are shown (A–O), and the quantified results are shown in P–R. n = 10 per group; **P < 0.01. Scale bar: 100 μm.