Ethanol Triggers Neural Crest Apoptosis through the Selective Activation of a Pertussis Toxin–Sensitive G Protein and a Phospholipase Cβ–Dependent Ca<sup>2+</sup> Transient

Garic-Stankovic, Ana; Hernandez, M. Rosario; Chiang, Po Jen; Debelak-Kragtorp, Katherine A.; Flentke, George R.; Armant, D. Randall; Smith, Susan

doi:10.1097/01.alc.0000172460.05756.d9

Cited by 53 publications

(100 citation statements)

References 51 publications

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“…Also, other G-protein receptor agonists can induce an apoptotic program via phospholipase C-InsP 3 R-Ca 2ϩ increase. For example, G-protein activation and subsequent interaction of G␤␥ with phospholipase C mediates the proapoptotic effects of ethanol in developing neural crest (51). The proapoptotic effects of the hormone angiotensin II also has been shown to mediate Ca 2ϩ release from internal stores via G-protein-coupled receptor (52).…”

Section: Discussionmentioning

confidence: 99%

Elevated Testosterone Induces Apoptosis in Neuronal Cells

Estrada¹,

Varshney²,

Ehrlich

2006

Journal of Biological Chemistry

143

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Testosterone plays a crucial role in neuronal function, but elevated concentrations can have deleterious effects. Here we show that supraphysiological levels of testosterone (micromolar range) initiate the apoptotic cascade. We used three criteria, annexin V labeling, caspase activity, and DNA fragmentation, to determine that apoptotic pathways were activated by testosterone. Micromolar, but not nanomolar, testosterone concentrations increased the response in all three assays of apoptosis. signals lead to apoptotic cell death. These effects of testosterone on neurons will have long term effects on brain function.Neurosteroids have been implicated as components essential for the normal function of the central nervous system (1-4). The gonadal steroid hormones are required for reproductive function, but androgens also affect areas of the brain that are not primarily involved in reproduction such as the hippocampus (5), preoptic area, amygdala, and medial hypothalamic area (6). At physiological levels, androgens are involved in neuronal differentiation, neuroprotection, neuronal survival and development (7-9). These responses occur slowly (over hours) and are mediated through the intracellular androgen receptor. In the developing brain, androgens are capable of changing the ultrastructural characteristics of the neuronal plasma membrane with a relatively fast pace (10, 11). Recently, we have shown that nanomolar levels of testosterone induce rapid intracellular Ca 2ϩ increases in neuroblastoma cells (within seconds), which begin as Ca 2ϩ transients in the cytosol, propagate as waves of Ca 2ϩ in the cytoplasm and nucleus, and develop into an oscillatory pattern (12). These Ca 2ϩ signals depend on an interplay between Ca 2ϩ efflux from the endoplasmic reticulum through inositol 1,4,5-trisphosphate-sensitive Ca 2ϩ release channels (InsP 3 Rs) 4 and Ca 2ϩ reuptake into the endoplasmic reticulum by Ca 2ϩ pumps. This new testosterone-induced pathway in neuronal cells leads to neurite outgrowth (12), an essential event in neuronal differentiation (13). These results suggest an important physiological mechanism for the action of testosterone in neurons at physiological concentrations. However, it is unknown how these cells respond to high plasma levels of this neurosteroid, generally administered exogenously to achieve an increase in muscle mass (14, 15) or for replacement therapy (16). In vivo administration of large doses of androgens has been correlated with neurobehavioral changes like hyperexcitability, supra-aggressive nature, and suicidal tendencies (17, 18). These behavioral changes could be the outward manifestation of neuronal damage resulting from exposure to high concentrations of testosterone.In this investigation, we evaluated the hypothesis that high concentrations of testosterone can induce deleterious effects in neurons. We show that high levels of testosterone initiate an apoptotic program in neuroblastoma cells. Apoptosis is the normal and controlled process of cell death (19). Precise control of apoptos...

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Section: Discussionmentioning

confidence: 99%

Elevated Testosterone Induces Apoptosis in Neuronal Cells

Estrada¹,

Varshney²,

Ehrlich

2006

Journal of Biological Chemistry

143

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“…To test for G i /G o -dependent actions of AgRP, slices were preincubated for at least 4 h in either pertussis toxin (PTX) (5 ug/ml) or 8,8Ј-[carbonylbis(imino-3,1-phenylene)]bis-(1,3,5-naphthalenetrisulfonic acid) (NF023) (10 uM) at 37°C as previously described Freissmuth et al, 1996;DeBock et al, 2003;Garic-Stankovic et al, 2005).…”

Section: Methodsmentioning

confidence: 99%

“…The G i/o -protein antagonists PTX and NF023 were used Freissmuth et al, 1996). Brain slices were preincubated in PTX or NF023 as described previously (DeBock et al, 2003;Garic-Stankovic et al, 2005) before using for whole-cell recording. AgRP (100 nM) failed to decrease the frequency of EPSCs significantly in either PTX-pretreated slices (84 Ϯ 6% of control; p Ͼ 0.05; ANOVA; n ϭ 6) or NF023-pretreated slices (94 Ϯ 12% of control; p Ͼ 0.05; ANOVA; n ϭ 7) (Fig.…”

Section: Agrp Inhibition In Vglut2 Neurons In Vmh Is G I/o -Protein Dmentioning

confidence: 99%

Agouti-Related Peptide and MC3/4 Receptor Agonists Both Inhibit Excitatory Hypothalamic Ventromedial Nucleus Neurons

Pol²

2008

J. Neurosci.

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Anorexigenic melanocortins decrease food intake by activating MC3/MC4 receptors (MC3/4R); the prevailing view is that the orexigenic neuropeptide agouti-related peptide (AgRP) exerts the opposite action by acting as an antagonist at MC3/MC4 receptors. A total of 370 hypothalamic ventromedial nucleus (VMH) glutamatergic neurons was studied using whole-cell recording in hypothalamic slices from a novel mouse expressing green fluorescent protein (GFP) under control of the vesicular glutamate transporter 2 (vGluT2) promoter. Massive numbers of GFP-expressing VMH dendrites extended out of the core of the nucleus into the surrounding cell-poor shell. VMH dendrites received frequent appositions from AgRP-immunoreactive axons in the shell of the nucleus, but not the core, suggesting that AgRP may influence target VMH neurons. ␣-MSH, melanotan II (MTII), and selective MC3R or MC4R agonists were all inhibitory, reducing the spontaneous firing rate and hyperpolarizing vGluT2 neurons. The MC3/4R antagonist SHU9119 was excitatory. Unexpectedly, AgRP did not attenuate MTII actions on these neurons; instead, these two compounds showed an additive inhibitory effect. In the absence of synaptic activity, no hyperpolarization or change in input resistance was evoked by either MTII or AgRP, suggesting indirect actions. Consistent with this view, MTII increased the frequency of spontaneous and miniature IPSCs. In contrast, the mechanism of AgRP inhibition was dependent on presynaptic inhibition of EPSCs mediated by G i /G o -proteins, and was attenuated by pertussis toxin and NF023, inconsistent with mediation by G s -proteins associated with MC receptors. Together, our data suggest that the mechanism of AgRP actions on these excitatory VMH cells appears to be independent of the actions of melanocortins on MC receptors.

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“…Specifically, exposure of early neuroprogenitors including neural crest to pharmacologically-relevant alcohol levels (10 to 100 mM) invokes a calcium transient (EC50 = 52 mM), similar to its effect on oocytes, gastrulating mouse embryos, and placental trophoblasts (Debelak-Kragtorp et al 2003; Garic-Stankovic et al 2006). This calcium transient originates from a pertussis toxin-sensitive G protein-coupled receptor (Gαi/o) and inositidyl-phosphate signaling in a dose-dependent manner (Garic-Stankovic et al 2005) and activates the calmodulin-dependent protein kinase CaMKII (Garic et al 2011); blockade of these steps using either small-molecule or targeted misexpression approaches normalizes neural crest survival in alcohol’s presence. Inhibition of other calcium-dependent kinases including protein kinase C and CaMKIV was ineffectual against alcohol, showing the pathway’s specificity.…”

Section: Mechanistic Insights From Avian Models Of Fasdmentioning

confidence: 99%

“…Eggs can also be windowed for precise staging (Hamburger and Hamilton, 1951) and for direct manipulation, such as the electroporation of expression constructions, or the application of small molecules using microbead delivery systems (i.e. Garic et al 2005). The window is sealed using leak-proof Scotch 3M black electrical tape.…”

Section: Experimental Factors For Avian Models Of Developmental Alcohmentioning

confidence: 99%

The avian embryo as a model for fetal alcohol spectrum disorder

Flentke

Smith

2018

Biochem. Cell Biol.

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Prenatal alcohol exposure (PAE) remains a leading preventable cause of structural birth defects and permanent neurodevelopmental disability. The chick (Gallus gallus domesticus) is a powerful embryological research model and was possibly the first (Fere, 1895) in which alcohol’s teratogenicity was demonstrated. Pharmacologically relevant alcohol exposures in the range of 20–70 mM (20–80 mg/egg) disrupt chick embryo growth, morphogenesis, and behavior, and the resulting phenotypes strongly parallel those of mammalian models. The avian embryo’s direct accessibility has enabled novel insights into alcohol’s teratogenic mechanisms. These include the contribution of IGF1 signaling to growth suppression, the altered flow dynamics that reshape valvuloseptal morphogenesis and mediate its cardiac teratogenicity, and the suppression of Wnt and Shh signals to disrupt neural crest migration, expansion, and survival and underlie its characteristic craniofacial deficits. The genetic diversity within commercial avian strains enabled identification of unique loci, such as ribosome biogenesis, that modify vulnerability to alcohol. This venerable research model is equally relevant for the future, as the application of technological advances including CRISPR, optogenetics, and biophotonics to the embryo’s ready accessibility creates a unique model in which investigators can manipulate and monitor the embryo in real-time to investigate alcohol’s actions upon cell fate.

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Ethanol Triggers Neural Crest Apoptosis through the Selective Activation of a Pertussis Toxin–Sensitive G Protein and a Phospholipase Cβ–Dependent Ca²⁺ Transient

Abstract: We propose a role for Galphai/o protein activation and subsequent interaction of Gbetagamma with PLCbeta in mediating the proapoptotic effects of ethanol upon the developing neural crest.

Cited by 53 publications

References 51 publications

Elevated Testosterone Induces Apoptosis in Neuronal Cells

Elevated Testosterone Induces Apoptosis in Neuronal Cells

Agouti-Related Peptide and MC3/4 Receptor Agonists Both Inhibit Excitatory Hypothalamic Ventromedial Nucleus Neurons

The avian embryo as a model for fetal alcohol spectrum disorder

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Ethanol Triggers Neural Crest Apoptosis through the Selective Activation of a Pertussis Toxin–Sensitive G Protein and a Phospholipase Cβ–Dependent Ca2+ Transient

Abstract: We propose a role for Galphai/o protein activation and subsequent interaction of Gbetagamma with PLCbeta in mediating the proapoptotic effects of ethanol upon the developing neural crest.

Cited by 53 publications

References 51 publications

Elevated Testosterone Induces Apoptosis in Neuronal Cells

Elevated Testosterone Induces Apoptosis in Neuronal Cells

Agouti-Related Peptide and MC3/4 Receptor Agonists Both Inhibit Excitatory Hypothalamic Ventromedial Nucleus Neurons

The avian embryo as a model for fetal alcohol spectrum disorder

Contact Info

Product

Resources

About

Ethanol Triggers Neural Crest Apoptosis through the Selective Activation of a Pertussis Toxin–Sensitive G Protein and a Phospholipase Cβ–Dependent Ca²⁺ Transient