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Lithium chloride attenuates cell death in oculopharyngeal muscular dystrophy by perturbing Wnt/β-catenin pathway.

Abu-Baker A, Laganiere J, Gaudet R, Rochefort D, Brais B, Neri C, Dion PA, Rouleau GA - Cell Death Dis (2013)

Bottom Line: Proteins that belong to the Wnt family are known for their role in both human development and adult tissue homeostasis.A hallmark of the Wnt signaling pathway is the increased expression of its central effector, beta-catenin (β-catenin) by inhibiting one of its upstream effector, glycogen synthase kinase (GSK)3β.Furthermore, this effect was also observed in primary cultures of mouse myoblasts expressing expPABPN1.

View Article: PubMed Central - PubMed

Affiliation: The Montreal Neurological Institute and Hospital, Department of Medicine, McGill University, Montréal, Québec H3A2B4, Canada.

ABSTRACT
Expansion of polyalanine tracts causes at least nine inherited human diseases. Among these, a polyalanine tract expansion in the poly (A)-binding protein nuclear 1 (expPABPN1) causes oculopharyngeal muscular dystrophy (OPMD). So far, there is no treatment for OPMD patients. Developing drugs that efficiently sustain muscle protection by activating key cell survival mechanisms is a major challenge in OPMD research. Proteins that belong to the Wnt family are known for their role in both human development and adult tissue homeostasis. A hallmark of the Wnt signaling pathway is the increased expression of its central effector, beta-catenin (β-catenin) by inhibiting one of its upstream effector, glycogen synthase kinase (GSK)3β. Here, we explored a pharmacological manipulation of a Wnt signaling pathway using lithium chloride (LiCl), a GSK-3β inhibitor, and observed the enhanced expression of β-catenin protein as well as the decreased cell death normally observed in an OPMD cell model of murine myoblast (C2C12) expressing the expanded and pathogenic form of the expPABPN1. Furthermore, this effect was also observed in primary cultures of mouse myoblasts expressing expPABPN1. A similar effect on β-catenin was also observed when lymphoblastoid cells lines (LCLs) derived from OPMD patients were treated with LiCl. We believe manipulation of the Wnt/β-catenin signaling pathway may represent an effective route for the development of future therapy for patients with OPMD.

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Related in: MedlinePlus

Choosing the best concentration of LiCl on the C2C12 cell line. LiCl (GSK inhibitor) at 2.5 mM maintains growth, size, and proliferation of C2C12 muscle cells. A dose-response experiment on non-transfected C2C12 cells shows that with a low dose of 2.5 mM LiCl, the cells maintain their growth and survival similarly to untreated cells. Cells were monitored under a live-stage Leica DMI 6000 microscope for morphology and viability. Phase images were captured at the indicated days after LiCl treatment. Higher concentrations of LiCl at 5 and 15 mM (top two rows) were toxic and caused the cells to die, while a concentration of 2.5 mM LiCl maintained the cells healthy and in good shape for 6 days. Therefore, 2.5 mM LiCl was the chosen concentration throughout the study
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fig1: Choosing the best concentration of LiCl on the C2C12 cell line. LiCl (GSK inhibitor) at 2.5 mM maintains growth, size, and proliferation of C2C12 muscle cells. A dose-response experiment on non-transfected C2C12 cells shows that with a low dose of 2.5 mM LiCl, the cells maintain their growth and survival similarly to untreated cells. Cells were monitored under a live-stage Leica DMI 6000 microscope for morphology and viability. Phase images were captured at the indicated days after LiCl treatment. Higher concentrations of LiCl at 5 and 15 mM (top two rows) were toxic and caused the cells to die, while a concentration of 2.5 mM LiCl maintained the cells healthy and in good shape for 6 days. Therefore, 2.5 mM LiCl was the chosen concentration throughout the study

Mentions: Glycogen synthase kinase-3 (GSK-3β) is a highly conserved protein constitutively active serine/threonine kinase ubiquitously expressed in eukaryotes.38 It has been implicated in many fundamental cellular functions, such as the cell cycle, gene transcription, and apoptosis, as a result of its ability to phosphorylate key proteins that modulate these processes.32 We investigated whether GSK-3-β inhibitor, LiCl, could be a promising drug for OPMD treatment. At first, we established the appropriate dose of LiCl to be used on C2C12 cells and monitored the number of viable cells exposed to different doses of LiCl in comparison with untreated control cells. This cell survival tracking assay was done over 6 days using a live-stage microscope and we found that 2.5 mM LiCl yielded the best cell survival rate. At dose 2.5 mM, LiCl maintains growth proliferation and survival of C2C12 cells (Figure 1). This concentration of LiCl mimics the extracellular fluid levels that would be observed in vivo with doses used to treat bipolar disorder patients.39 At 10 and 15 mM, LiCl was toxic and caused the cells to die and detach from the culture dish. Thus, we chose 2.5 mM of LiCl to continue with our study. Figure 1 represents the effects of different doses of LiCl on the morphology and survival of C2C12 cells.


Lithium chloride attenuates cell death in oculopharyngeal muscular dystrophy by perturbing Wnt/β-catenin pathway.

Abu-Baker A, Laganiere J, Gaudet R, Rochefort D, Brais B, Neri C, Dion PA, Rouleau GA - Cell Death Dis (2013)

Choosing the best concentration of LiCl on the C2C12 cell line. LiCl (GSK inhibitor) at 2.5 mM maintains growth, size, and proliferation of C2C12 muscle cells. A dose-response experiment on non-transfected C2C12 cells shows that with a low dose of 2.5 mM LiCl, the cells maintain their growth and survival similarly to untreated cells. Cells were monitored under a live-stage Leica DMI 6000 microscope for morphology and viability. Phase images were captured at the indicated days after LiCl treatment. Higher concentrations of LiCl at 5 and 15 mM (top two rows) were toxic and caused the cells to die, while a concentration of 2.5 mM LiCl maintained the cells healthy and in good shape for 6 days. Therefore, 2.5 mM LiCl was the chosen concentration throughout the study
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3824652&req=5

fig1: Choosing the best concentration of LiCl on the C2C12 cell line. LiCl (GSK inhibitor) at 2.5 mM maintains growth, size, and proliferation of C2C12 muscle cells. A dose-response experiment on non-transfected C2C12 cells shows that with a low dose of 2.5 mM LiCl, the cells maintain their growth and survival similarly to untreated cells. Cells were monitored under a live-stage Leica DMI 6000 microscope for morphology and viability. Phase images were captured at the indicated days after LiCl treatment. Higher concentrations of LiCl at 5 and 15 mM (top two rows) were toxic and caused the cells to die, while a concentration of 2.5 mM LiCl maintained the cells healthy and in good shape for 6 days. Therefore, 2.5 mM LiCl was the chosen concentration throughout the study
Mentions: Glycogen synthase kinase-3 (GSK-3β) is a highly conserved protein constitutively active serine/threonine kinase ubiquitously expressed in eukaryotes.38 It has been implicated in many fundamental cellular functions, such as the cell cycle, gene transcription, and apoptosis, as a result of its ability to phosphorylate key proteins that modulate these processes.32 We investigated whether GSK-3-β inhibitor, LiCl, could be a promising drug for OPMD treatment. At first, we established the appropriate dose of LiCl to be used on C2C12 cells and monitored the number of viable cells exposed to different doses of LiCl in comparison with untreated control cells. This cell survival tracking assay was done over 6 days using a live-stage microscope and we found that 2.5 mM LiCl yielded the best cell survival rate. At dose 2.5 mM, LiCl maintains growth proliferation and survival of C2C12 cells (Figure 1). This concentration of LiCl mimics the extracellular fluid levels that would be observed in vivo with doses used to treat bipolar disorder patients.39 At 10 and 15 mM, LiCl was toxic and caused the cells to die and detach from the culture dish. Thus, we chose 2.5 mM of LiCl to continue with our study. Figure 1 represents the effects of different doses of LiCl on the morphology and survival of C2C12 cells.

Bottom Line: Proteins that belong to the Wnt family are known for their role in both human development and adult tissue homeostasis.A hallmark of the Wnt signaling pathway is the increased expression of its central effector, beta-catenin (β-catenin) by inhibiting one of its upstream effector, glycogen synthase kinase (GSK)3β.Furthermore, this effect was also observed in primary cultures of mouse myoblasts expressing expPABPN1.

View Article: PubMed Central - PubMed

Affiliation: The Montreal Neurological Institute and Hospital, Department of Medicine, McGill University, Montréal, Québec H3A2B4, Canada.

ABSTRACT
Expansion of polyalanine tracts causes at least nine inherited human diseases. Among these, a polyalanine tract expansion in the poly (A)-binding protein nuclear 1 (expPABPN1) causes oculopharyngeal muscular dystrophy (OPMD). So far, there is no treatment for OPMD patients. Developing drugs that efficiently sustain muscle protection by activating key cell survival mechanisms is a major challenge in OPMD research. Proteins that belong to the Wnt family are known for their role in both human development and adult tissue homeostasis. A hallmark of the Wnt signaling pathway is the increased expression of its central effector, beta-catenin (β-catenin) by inhibiting one of its upstream effector, glycogen synthase kinase (GSK)3β. Here, we explored a pharmacological manipulation of a Wnt signaling pathway using lithium chloride (LiCl), a GSK-3β inhibitor, and observed the enhanced expression of β-catenin protein as well as the decreased cell death normally observed in an OPMD cell model of murine myoblast (C2C12) expressing the expanded and pathogenic form of the expPABPN1. Furthermore, this effect was also observed in primary cultures of mouse myoblasts expressing expPABPN1. A similar effect on β-catenin was also observed when lymphoblastoid cells lines (LCLs) derived from OPMD patients were treated with LiCl. We believe manipulation of the Wnt/β-catenin signaling pathway may represent an effective route for the development of future therapy for patients with OPMD.

Show MeSH
Related in: MedlinePlus