Inhibition of Autophagy Prevents Hippocampal Pyramidal Neuron Death after Hypoxic-Ischemic Injury

Koike, Masato; Shibata, Masahiro; Tadakoshi, Masao; Gotoh, Kunihito; Komatsu, Masaaki; Waguri, Satoshi; Kawahara, Nobutaka; Kuida, Keisuke; Nagata, Shinji; Kominami, Eiki; Tanaka, Keiji; Uchiyama, Yasuo

doi:10.2353/ajpath.2008.070876

Cited by 449 publications

(419 citation statements)

References 60 publications

(94 reference statements)

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“…Chronic myocardial ischemia/reperfusion injury induces autophagy increment and apoptosis decrement [9]. Inhibition of autophagy prevents neuron death after hypoxic-ischemic injury in neonatal mice [10]. However, in acute kidney injury (AKI), the association between autophagy and cell death is not obvious.…”

Section: Discussionmentioning

confidence: 99%

Cisplatin-induced macroautophagy occurs prior to apoptosis in proximal tubules in vivo

et al. 2009

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Background. Autophagy is an intracellular bulk degradation process induced by cell starvation. Autophagy was recently reported to be induced by various stresses such as hypoxia, ischemia/reperfusion, toxins, and denatured proteins, and to affect cell survival and death. Light chain 3-II (LC3-II) is specifically located on double membrane-bound autophagosomes that envelop disused proteins or organelles. Method. Transgenic mice in which green fluorescent protein (GFP) was fused to LC3(LC3-GFP) were administered cisplatin (20 mg/kg). After euthanasia at times between 0-72 hours, kidneys were excised for immunohistochemical analyses.Microscopic examinations of the generated NRK-52E cell lines stably transfected with LC3-GFP, and western blot analyses of NRK-52E cells were undertaken after cisplatin treatment with or without autophagy inhibitors and beclin 1 siRNA.Results. Autophagosomes increased in the proximal tubular cells of transgenic mice from 12 hours after cisplatin injection (20 mg/kg). The time course for this was faster than those for tubular necrosis and apoptosis. Autophagosomes also increased in NRK-52E cells after cisplatin treatment, with the time course for this faster than that for apoptosis. When autophagy was suppressed by autophagy inhibitors or beclin 1 siRNA, the level of apoptosis was also suppressed. Conclusion.Autophagy occurs in proximal tubular cells after cisplatin treatment and is involved in cell death in renal tubular injury. Our data suggested that autophagy is a kind of cell damage index and cells with activated autophagy will be scavenged by apoptosis. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 4 and in other cases induces apoptosis or type-2 programmed cell death [6][7][8]. Chronic myocardial ischemia/reperfusion injury induces autophagy increment and apoptosis decrement [9]. Inhibition of autophagy prevents neuron death after hypoxic-ischemic injury in neonatal mice [10]. However, in acute kidney injury (AKI), the association between autophagy and cell death is not obvious.Cisplatin is a major chemotherapeutic drug against solid tumors. One of the most important side effects of cisplatin is nephrotoxicity. Cisplatin is freely filtered at the Subjects and Methods MaterialsAnti-light chain 3 antibody was purchased from MBL (Nagoya, Japan).Anti-aquaporin-1 antibody was purchased from Abcam (Cambridge, MA).Anti-cleaved caspase 3 and rapamycin were purchased from Cell Signaling (Danvers, 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 Cell CultureThe NRK-52E cell line was obtained from ATCC (Manassas, VA), and cultured in DMEM medium containing 10% fetal bovine serum, 100 u...

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Section: Discussionmentioning

confidence: 99%

Cisplatin-induced macroautophagy occurs prior to apoptosis in proximal tubules in vivo

et al. 2009

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“…In cancer cells, autophagy inhibited starvation-induced apoptotic death (Boya et al, 2005) and also necrotic cell death, especially in conjunction with a block in apoptosis (Jin and White, 2007;Karantza-Wadsworth et al, 2007). Conversely, autophagy was required for necrotic death of neuronal cells in C. elegans (Samara et al, 2008), for stress-mediated necrosis in apoptosis-deficient BaxÀ/ÀBakÀ/À mouse embryonic fibroblasts (MEFs) (Shimizu et al, 2004;Ullman et al, 2008) and loss of autophagy through deletion of Atg7 rescued neurons from death after hypoxia/reperfusion (Koike et al, 2008). Resolving the relationship between autophagy and apoptosis is especially complex, as both are induced by similar stimuli and impact on each other's functions (Maiuri et al, 2007c;Levine et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Bcl-2 complexed with Beclin-1 maintains full anti-apoptotic function

et al. 2009

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The binding of Bcl-2 to Beclin-1 reduces Beclin-1's capacity to induce autophagy. Here, we have tested whether the interaction is reciprocated by loss of Bcl-2's anti-apoptotic function. We targeted Bcl-2 to mitochondria or endoplasmic reticulum (ER) and induced apoptosis using several apoptotic stimuli that initiate ER and/or mitochondrial signaling pathways (UV radiation, TNF and cycloheximide, staurosporine, thapsigargin and tunicamycin). When Beclin-1 and Bcl-2 were expressed together in HeLa cells, Beclin-1 (but not Beclin-1 lacking the Bcl-2-binding domain) followed Bcl-2 to the appropriate organelle with complete or near-complete overlap (comprising 60 and 30% of cells, respectively). The interaction between Beclin-1 and Bcl-2 was verified by immunoprecipitation, and a membrane-proximate localization of Beclin-1 was shown by immunoelectron microscopy. Apoptosis was followed by measuring changes in nuclear morphology, caspase-3 activity, poly-ADP-ribose polymerase cleavage or punctation of mRFP-Bax on mitochondria. Binding of Beclin-1 to Bcl-2 did not modify apoptosis irrespective of Bcl-2 concentration, location or apoptotic stimulus. A similar result was obtained in Atg5À/À cells that are autophagy-deficient, arguing against compensation for the loss of protection by Bcl-2 by autophagy-mediated survival induced by Beclin-1. Hence, although Beclin-1 contains a BH3-only motif typical of pro-apoptotic proteins, it is a negligible modulator of Bcl-2's anti-apoptotic function.

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“…9,25,26 Previous studies including ones from our laboratory have demonstrated that hypoxia can induce autophagy, triggering either a cell survival or cell death response depending upon the context. [27][28][29][30][31][32][33][34][35][36][37][38] A recent study demonstrates that autosis, possibly a subtype of autophagic cell death, is induced by hypoxia-ischemia treatment. 39,40 The mechanism governing whether autophagy contributes to cell survival or to cell death is still not well understood, and whether there is a tipping point between these 2 events is unknown.…”

Section: Introductionmentioning

confidence: 99%

Tyrosine kinase receptor EGFR regulates the switch in cancer cells between cell survival and cell death induced by autophagy in hypoxia

et al. 2016

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(2016) Tyrosine kinase receptor EGFR regulates the switch in cancer cells between cell survival and cell death induced by autophagy in hypoxia, Autophagy, 12:6, 1029-1046, DOI: 10.1080/15548627.2016 ABSTRACTAutophagy is an intracellular lysosomal degradation pathway where its primary function is to allow cells to survive under stressful conditions. Autophagy is, however, a double-edge sword that can either promote cell survival or cell death. In cancer, hypoxic regions contribute to poor prognosis due to the ability of cancer cells to adapt to hypoxia in part through autophagy. In contrast, autophagy could contribute to hypoxia induced cell death in cancer cells. In this study, we showed that autophagy increased during hypoxia. At 4 h of hypoxia, autophagy promoted cell survival whereas, after 48 h of hypoxia, autophagy increased cell death. Furthermore, we found that the tyrosine phosphorylation of EGFR (epidermal growth factor receptor) decreased after 16 h in hypoxia. Furthermore, EGFR binding to BECN1 in hypoxia was significantly higher at 4 h compared to 72 h. Knocking down or inhibiting EGFR resulted in an increase in autophagy contributing to increased cell death under hypoxia. In contrast, when EGFR was reactivated by the addition of EGF, the level of autophagy was reduced which led to decreased cell death. Hypoxia led to autophagic degradation of the lipid raft protein CAV1 (caveolin 1) that is known to bind and activate EGFR in a ligand-independent manner during hypoxia. By knocking down CAV1, the amount of EGFR phosphorylation was decreased in hypoxia and amount of autophagy and cell death increased. This indicates that the activation of EGFR plays a critical role in the switch between cell survival and cell death induced by autophagy in hypoxia.

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Inhibition of Autophagy Prevents Hippocampal Pyramidal Neuron Death after Hypoxic-Ischemic Injury

Cited by 449 publications

References 60 publications

Cisplatin-induced macroautophagy occurs prior to apoptosis in proximal tubules in vivo

Cisplatin-induced macroautophagy occurs prior to apoptosis in proximal tubules in vivo

Bcl-2 complexed with Beclin-1 maintains full anti-apoptotic function

Tyrosine kinase receptor EGFR regulates the switch in cancer cells between cell survival and cell death induced by autophagy in hypoxia

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