Secretin Prevents Apoptosis in the Developing Cerebellum Through Bcl-2 and Bcl-xL
Secretin (SCT) is involved in a variety of physiological processes and has been implicated in preventing apoptosis during brain development. However, little is known about the molecular mechanism underlying its neuroprotective effects. The B cell lymphoma 2 (Bcl-2) family proteins, such as Bcl-2 and Bcl-xL, determine the commitment of neurons to apoptosis. In SCT knockout mice, we found reduced transcript levels of anti-apoptotic genes Bcl-2 and Bcl-xL, but not of pro-apoptotic gene Bax, in the developing cerebellum. SCT treatment on ex vivo cultured cerebellar slices triggered a time-dependent increase of Bcl-2 and Bcl-xL expression. This SCT-induced transcriptional regulation of Bcl-2 and Bcl-xL was dependent on the cyclic AMP (cAMP) response element-binding protein (CREB), which is a key survival factor at the convergence of multiple signaling cascades. We further demonstrated that activation of CREB by SCT was mediated by cAMP/protein kinase A (PKA) and mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase 1/2 (ERK1/2) cascades. These findings, collectively, provide an uncharacterized signaling cascade for SCT-mediated neuronal survival, in which SCT promotes the key anti-apoptotic elements Bcl-2 and Bcl-xL in the intrinsic death pathway through PKA- and ERK-regulated CREB phosphorylation.
KeywordsSecretin Apoptosis Bcl-2 family proteins CREB PKA ERK1/2
This work is supported by Hong Kong Research Grant Council grant GRF 765113M to Professor B.K.C. Chow, and National Natural Science Foundation of China (#31500842) to Dr. L. Zhang.
Compliance with Ethical Standards
All animal experiments were conducted according to the protocols approved by Committee on the Use of Living Animals in Teaching and Research at the University of Hong Kong.
Conflict of Interest Statement
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
- Ballif BA, Blenis J (2001) Molecular mechanisms mediating mammalian mitogen-activated protein kinase (MAPK) kinase (MEK)-MAPK cell survival signals. Cell Growth Differ 12:397–408Google Scholar
- Bhave S, Hoffman P (2004) Phosphatidylinositol 3′-OH kinase and protein kinase a pathways mediate the anti-apoptotic effect of pituitary adenylyl cyclase-activating polypeptide in cultured cerebellar granule neurons: modulation by ethanol. J Neurochem 88:359–369. https://doi.org/10.1046/j.1471-4159.2003.02167.x CrossRefGoogle Scholar
- Dohi K, Mizushima H, Nakajo S, Ohtaki H, Matsunaga S, Aruga T, Shioda S (2002) Pituitary adenylate cyclase-activating polypeptide (PACAP) prevents hippocampal neurons from apoptosis by inhibiting JNK/SAPK and p38 signal transduction pathways. Regul Pept 109:83–88. https://doi.org/10.1016/S0167-0115(02)00190-8 CrossRefGoogle Scholar
- Falluel-Morel A, Aubert N, Vaudry D, Basille M, Fontaine M, Fournier A, Vaudry H, Gonzalez BJ (2004) Opposite regulation of the mitochondrial apoptotic pathway by C2-ceramide and PACAP through a MAP-kinase-dependent mechanism in cerebellar granule cells. J Neurochem 91:1231–1243CrossRefGoogle Scholar
- Gutiérrez-Cañas I, Rodríguez-Henche N, Bolaños O, Carmena MJ, Prieto JC, Juarranz MG (2003) VIP and PACAP are autocrine factors that protect the androgen-independent prostate cancer cell line PC-3 from apoptosis induced by serum withdrawal. Brit J Pharmacol 139:1050–1058. https://doi.org/10.1038/sj.bjp.0705317 CrossRefGoogle Scholar
- Hurtado de Mendoza T, Balana B, Slesinger PA, Verma IM (2011) Organotypic cerebellar cultures: apoptotic challenges and detection. J Vis Exp. https://doi.org/10.3791/2564
- Kim S-J, Nian C, Widenmaier S, McIntosh CH (2008) Glucose-dependent insulinotropic polypeptide-mediated up-regulation of β-cell antiapoptotic Bcl-2 gene expression is coordinated by cyclic AMP (cAMP) response element binding protein (CREB) and cAMP-responsive CREB coactivator 2. Mol Cell Biol 28:1644–1656CrossRefGoogle Scholar
- Kluck RM, Esposti MD, Perkins G, Renken C, Kuwana T, Bossy-Wetzel E, Goldberg M, Allen T, Barber MJ, Green DR, Newmeyer DD (1999) The pro-apoptotic proteins, bid and Bax, cause a limited permeabilization of the mitochondrial outer membrane that is enhanced by cytosol. J Cell Biol 147:809–822CrossRefGoogle Scholar
- May V, Lutz E, MacKenzie C, Schutz KC, Dozark K, Braas KM (2010) Pituitary adenylate cyclase-activating polypeptide (PACAP)/PAC1HOP1 receptor activation coordinates multiple neurotrophic signaling pathways: Akt activation through phosphatidylinositol 3-kinase gamma and vesicle endocytosis for neuronal survival. J Biol Chem 285:9749–9761. https://doi.org/10.1074/jbc.M109.043117 CrossRefGoogle Scholar
- Merry DE, Veis DJ, Hickey WF, Korsmeyer SJ (1994) Bcl-2 protein expression is widespread in the developing nervous system and retained in the adult PNS. Development 120:301–311Google Scholar
- Wang L, Zhang L, Chow BKC (2017) Secretin modulates the postnatal development of mouse cerebellar cortex via PKA- and ERK-dependent pathways. Front Cell Neurosci 11. https://doi.org/10.3389/fncel.2017.00382
- Wei MC, Lindsten T, Mootha VK, Weiler S, Gross A, Ashiya M, Thompson CB, Korsmeyer SJ (2000) tBID, a membrane-targeted death ligand, oligomerizes BAK to release cytochrome c. Genes Dev 14:2060–2071Google Scholar