To investigate the interconnection of apoptosis and autophagy in trophoblastic cells, we treated JEG-3 cells with tumor necrosis factor α (TNF-α) after transfecting LC3 or Beclin 1 or calpain small interfering RNA (siRNA), which blocks cleavage of autophagy-related gene 5 (Atg5) into N-terminal truncated Atg5 (tAtg5), a mediator between apoptosis and autophagy, and assessed the changes in LC3-II, caspase 9, caspase 3, and tAtg5. We also assessed the TNF-α-induced changes in LC3-II, caspase 9, and caspase 3 in primary trophoblasts from term placentae after transfecting siRNA for LC3 or Beclin 1. In both types of cells, transfection of LC3 or Beclin 1 siRNA significantly attenuated TNF-α-induced increases in LC3-II and activations of caspase 9 and caspase 3. There was significant abrogation of TNF-α-induced expression of tAtg5 after transfection with LC3 or Beclin 1 siRNA. Moreover, transfection with calpain siRNA significantly decreased TNF-α-induced changes in caspase 3 and caspase 9 in addition to tAtg5 in JEG-3 cells. Our data suggest that TNF-α-induced autophagy mediates intrinsic apoptosis, probably through tAtg5, in trophoblastic cells.
AbumareeMHStonePRChamleyLW. An in vitro model of human placental trophoblast deportation/shedding. Mol Hum Reprod. 2006;12(11):687–694.
2.
Straszewski-ChavezSLAbrahamsVMMorG. The role of apoptosis in the regulation of trophoblast survival and differentiation during pregnancy. Endocr Rev. 2005;26(7):877–897.
3.
CrockerIPCooperSOngSCBakerPN. Differences in apoptotic susceptibility of cytotrophoblasts and syncytiotrophoblasts in normal pregnancy to those complicated with preeclampsia and intrauterine growth restriction. Am J Pathol. 2003;162(2):637–643.
4.
HuppertzBKadyrovMKingdomJC. Apoptosis and its role in the trophoblast. Am J Obstet Gynecol. 2006;195(1):29–39.
5.
IshiharaNMatsuoHMurakoshiHLaoag-FernandezJBSamotoTMaruoT. Increased apoptosis in the syncytiotrophoblast in human term placentas complicated by either preeclampsia or intrauterine growth retardation. Am J Obstet Gynecol. 2002;186(1):158–166.
6.
TuuliMGLongtineMSNelsonDM. Review: Oxygen and trophoblast biology—a source of controversy. Placenta. 2011;32(suppl 2):S109–S118.
7.
ChoiAMRyterSWLevineB. Autophagy in human health and diasease. N Engl J Med. 2013;368(7):651–662.
8.
LiangC. Negative regulation of autophagy. Cell Death Differ. 2010;17(12):1807–1815.
9.
OhSYChoiSJKimKHChoEYKimJHRohCR. Autophagy-related proteins, LC3 and Beclin-1, in placentas from pregnancies complicated by preeclampsia. Reprod Sci. 2008;15(9):912–920.
10.
SignorelliPAvaglianoLVirgiliE. Autophagy in term normal human placentas. Placenta. 2011;32(6):482–485.
11.
LeeJEOhHASongH. Autophagy regulates embryonic survival during delayed implantation. Endocrinology. 2011;152(5):2067–2075.
12.
LuoSRubinszteinDC. Atg5 and Bcl-2 provide novel insights into the interplay between apoptosis and autophagy. Cell Death Differ. 2007;14(7):1247–1250.
13.
YousefiSPerozzoRSchmidI. Calpain-mediated cleavage of Atg5 switches autophagy to apoptosis. Nat Cell Biol. 2006;8(10):1124–1132.
14.
GozuacikDKimchiA. Autophagy as a cell death and tumor suppressor mechanism. Oncogene. 2004;23(16):2891–2906.
15.
MaiuriMCZalckvarEKimchiAKroemerG. Self-eating and self-killing: crosstalk between autophagy and apoptosis. Nat Rev Mol Cell Biol. 2007;8(9):741–752.
16.
KlimanHJNestlerJESermasiESangerJMStraussJF III. Purification, characterization, and in vitro differentiation of cytotrophoblasts from human term placentae. Endocrinology. 1986;118(4):1567–1582.
17.
AntebyEYJohnsonRDHuangXNelsonDMSadovskyY. Transcriptional regulation of prostaglandin-H synthase-2 gene in human trophoblasts. J Clin Endocrinol Metab. 1997;82(7):2289–2293.
18.
ShackaJJKlockeBJRothKA. Autophagy, bafilomycin and cell death: the “a-B-cs” of plecomacrolide-induced neuroprotection. Autophagy. 2006;2(3):228–230.
19.
BhutiaSKDashRDasSK. Mechanism of autophagy to apoptosis switch triggered in prostate cancer cells by antitumor cytokine melanoma differentiation-associated gene 7/interleukin-24. Cancer Res. 2010;70(9):3667–3676.
20.
LianJWuXHeF. A natural BH3 mimetic induces autophagy in apoptosis-resistant prostate cancer via modulating Bcl-2-Beclin1 interaction at endoplasmic reticulum. Cell Death Differ. 2011;18(1):60–71.
21.
TsudaHOchiaiKSuzukiNOtsukaK. Butyrate, a bacterial metabolite, induces apoptosis and autophagic cell death in gingival epithelial cells. J Periodontal Res. 2010;45(5):626–634.
22.
VossVSenftCLangV. The pan-Bcl-2 inhibitor (-)-gossypol triggers autophagic cell death in malignant glioma. Mol Cancer Res. 2010;8(7):1002–1016.
23.
ChenBLongtineMSNelsonDM. Hypoxia induces autophagy in primary human trophoblasts. Endocrinology. 2012;153(10):4946–4954.
24.
JiaLDourmashkinRRAllenPDGrayABNewlandACKelseySM. Inhibition of autophagy abrogates tumour necrosis factor alpha induced apoptosis in human T-lymphoblastic leukaemic cells. Br J Haematol. 1997;98(3):673–685.
25.
XueLFletcherGCTolkovskyAM. Autophagy is activated by apoptotic signalling in sympathetic neurons: an alternative mechanism of death execution. Mol Cell Neurosci. 1999;14(3):180–198.
26.
YuLAlvaASuH. Regulation of an ATG7-beclin 1 program of autophagic cell death by caspase-8. Science. 2004;304(5676):1500–1502.
27.
KanzawaTKondoYItoHKondoSGermanoI. Induction of autophagic cell death in malignant glioma cells by arsenic trioxide. Cancer Res. 2003;63(9):2103–2108.
28.
BoyaPGonzalez-PoloRACasaresN. Inhibition of macroautophagy triggers apoptosis. Mol Cell Biol. 2005;25(3):1025–1040.
29.
HouWHanJLuCGoldsteinLARabinowichH. Autophagic degradation of active caspase-8: a crosstalk mechanism between autophagy and apoptosis. Autophagy. 2010;6(7):891–900.
30.
Djavaheri-MergnyMMaiuriMCKroemerG. Cross talk between apoptosis and autophagy by caspase-mediated cleavage of Beclin 1. Oncogene. 2010;29(12):1717–1719.
31.
ZhouFYangYXingD. Bcl-2 and Bcl-xL play important roles in the crosstalk between autophagy and apoptosis. FEBS J. 2011;278(3):403–413.
32.
CiechomskaIAGoemansGCSkepperJNTolkovskyAM. Bcl-2 complexed with Beclin-1 maintains full anti-apoptotic function. Oncogene. 2009;28(21):2128–2141.
33.
BildiriciILongineMSChenBNelsonDM. Survival by self-destruction: a role for autophagy in the placenta?Placenta. 2012;33(8):591–598.
