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Transient receptor potential ion channel Trpm7 regulates exocrine pancreatic epithelial proliferation by Mg2+-sensitive Socs3a signaling in development and cancer.

Yee NS, Zhou W, Liang IC - Dis Model Mech (2010)

Bottom Line: The role of Socs3a in Trpm7-mediated signaling is supported by the findings that socs3a mRNA level is elevated in the trpm7 mutants, and antisense inhibition of socs3a expression improved their exocrine pancreatic growth.TRPM7 is generally overexpressed in human pancreatic adenocarcinoma.Results of this study indicate that Trpm7 regulates exocrine pancreatic development via the Mg(2+)-sensitive Socs3a pathway, and suggest that aberrant TRPM7-mediated signaling contributes to pancreatic carcinogenesis.

View Article: PubMed Central - PubMed

Affiliation: Division of Hematology, Oncology, and Blood & Marrow Transplantation, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA. nelson-yee@uiowa.edu

ABSTRACT
Genetic analysis of pancreatic development has provided new insights into the mechanisms underlying the formation of exocrine pancreatic neoplasia. Zebrafish sweetbread (swd) mutants develop hypoplastic acini and dysmorphic ducts in the exocrine pancreas, with impeded progression of cell division cycle and of epithelial growth. Positional cloning and allelic complementation have revealed that the swd mutations affect the transient receptor potential melastatin-subfamily member 7 (trpm7) gene, which encodes a divalent cation-permeable channel with kinase activity. Supplementary Mg(2+) partially rescued the exocrine pancreatic defects of the trpm7 mutants by improving cell-cycle progression and growth and repressing the suppressor of cytokine signaling 3a (socs3a) gene. The role of Socs3a in Trpm7-mediated signaling is supported by the findings that socs3a mRNA level is elevated in the trpm7 mutants, and antisense inhibition of socs3a expression improved their exocrine pancreatic growth. TRPM7 is generally overexpressed in human pancreatic adenocarcinoma. TRPM7-deficient cells are impaired in proliferation and arrested in the G0-G1 phases of the cell division cycle. Supplementary Mg(2+) rescued the proliferative defect of the TRPM7-deficient cells. Results of this study indicate that Trpm7 regulates exocrine pancreatic development via the Mg(2+)-sensitive Socs3a pathway, and suggest that aberrant TRPM7-mediated signaling contributes to pancreatic carcinogenesis.

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The Mg2+-sensitive Socs3a pathway is involved in the proliferative defect of the swd mutants. Supplementary Mg2+ improves the exocrine pancreas phenotype of the swd mutants that have repression of socs3a. (A) swdp75fm mutants were incubated in E3 medium with or without supplementary 40 mM MgCl2 for 72 or 96 hpf and analyzed for socs3a mRNA by real-time PCR. (B) swdp75fm mutants and WT were incubated in E3 medium (containing 1.65 mM Mg2+) for 72 or 96 hpf, and the socs3a mRNA levels were determined by real-time PCR. (C) Embryos collected from swdp75fm/+ intercross were microinjected with socs3a-ATG-MO or control MO, incubated until 4 dpf and the exocrine pancreas (red arrows) was analyzed by whole-mount in situ hybridization using anti-trypsin riboprobes. The image is representative of 20 larvae in each group from three independent experiments. The swdp75fm mutants injected with either non-targeting control MO or socs3a-5-mispair MO are indistinguishable in the exocrine pancreas by in situ hybridization using anti-trypsin riboprobes. (D) socs3a-ATG-MO- or control-MO-injected larvae were incubated until 72 hpf, injected with BrdU and then analyzed for the proportion of cells in S phase (% BrdU+ nuclei). (E) socs3a-ATG-MO- or control-MO-injected larvae were incubated until 96 hpf and analyzed for cell growth (area, in μm2, per cell). *P<0.05 indicates statistically significant difference. (C-E) The swdp75fm mutants were identified on the basis of their hypopigmented skin, which was not grossly affected by socs3a-ATG-MO.
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f6-0040240: The Mg2+-sensitive Socs3a pathway is involved in the proliferative defect of the swd mutants. Supplementary Mg2+ improves the exocrine pancreas phenotype of the swd mutants that have repression of socs3a. (A) swdp75fm mutants were incubated in E3 medium with or without supplementary 40 mM MgCl2 for 72 or 96 hpf and analyzed for socs3a mRNA by real-time PCR. (B) swdp75fm mutants and WT were incubated in E3 medium (containing 1.65 mM Mg2+) for 72 or 96 hpf, and the socs3a mRNA levels were determined by real-time PCR. (C) Embryos collected from swdp75fm/+ intercross were microinjected with socs3a-ATG-MO or control MO, incubated until 4 dpf and the exocrine pancreas (red arrows) was analyzed by whole-mount in situ hybridization using anti-trypsin riboprobes. The image is representative of 20 larvae in each group from three independent experiments. The swdp75fm mutants injected with either non-targeting control MO or socs3a-5-mispair MO are indistinguishable in the exocrine pancreas by in situ hybridization using anti-trypsin riboprobes. (D) socs3a-ATG-MO- or control-MO-injected larvae were incubated until 72 hpf, injected with BrdU and then analyzed for the proportion of cells in S phase (% BrdU+ nuclei). (E) socs3a-ATG-MO- or control-MO-injected larvae were incubated until 96 hpf and analyzed for cell growth (area, in μm2, per cell). *P<0.05 indicates statistically significant difference. (C-E) The swdp75fm mutants were identified on the basis of their hypopigmented skin, which was not grossly affected by socs3a-ATG-MO.

Mentions: To gain insight into the mechanism by which supplementary Mg2+ improves the exocrine pancreatic phenotype, the swdp75fm mutants and their WT siblings were incubated in the absence (–) or presence (+) of added 40 mM MgCl2 and analyzed by transcriptional profiling. In the swdp75fm mutants (+Mg2+), expression of the negative modulator of epidermal growth factor (Egf)-induced proliferation, socs3a, was downregulated by 187% as compared with the swdp75fm mutants (–Mg2+) (supplementary material Table S2A, gene #5), and this was confirmed by real-time PCR (Fig. 6A). Similarly, the socs3a mRNA level was repressed by supplementary Mg2+ in the trpm7b508 mutants, as compared with that in the trpm7b508 mutants incubated without supplementary Mg2+ (supplementary material Fig. S1E). Expression of socs3a was verified to be upregulated in the swdp75fm mutants and trpm7b508 mutants relative to WT (all incubated in E3 medium without supplementary Mg2+), as indicated by real-time PCR (Fig. 6B; supplementary material Table S3, Fig. S1E). These data strongly suggest that Mg2+-modulated expression of socs3a mRNA is involved in the proliferative effect of Trpm7.


Transient receptor potential ion channel Trpm7 regulates exocrine pancreatic epithelial proliferation by Mg2+-sensitive Socs3a signaling in development and cancer.

Yee NS, Zhou W, Liang IC - Dis Model Mech (2010)

The Mg2+-sensitive Socs3a pathway is involved in the proliferative defect of the swd mutants. Supplementary Mg2+ improves the exocrine pancreas phenotype of the swd mutants that have repression of socs3a. (A) swdp75fm mutants were incubated in E3 medium with or without supplementary 40 mM MgCl2 for 72 or 96 hpf and analyzed for socs3a mRNA by real-time PCR. (B) swdp75fm mutants and WT were incubated in E3 medium (containing 1.65 mM Mg2+) for 72 or 96 hpf, and the socs3a mRNA levels were determined by real-time PCR. (C) Embryos collected from swdp75fm/+ intercross were microinjected with socs3a-ATG-MO or control MO, incubated until 4 dpf and the exocrine pancreas (red arrows) was analyzed by whole-mount in situ hybridization using anti-trypsin riboprobes. The image is representative of 20 larvae in each group from three independent experiments. The swdp75fm mutants injected with either non-targeting control MO or socs3a-5-mispair MO are indistinguishable in the exocrine pancreas by in situ hybridization using anti-trypsin riboprobes. (D) socs3a-ATG-MO- or control-MO-injected larvae were incubated until 72 hpf, injected with BrdU and then analyzed for the proportion of cells in S phase (% BrdU+ nuclei). (E) socs3a-ATG-MO- or control-MO-injected larvae were incubated until 96 hpf and analyzed for cell growth (area, in μm2, per cell). *P<0.05 indicates statistically significant difference. (C-E) The swdp75fm mutants were identified on the basis of their hypopigmented skin, which was not grossly affected by socs3a-ATG-MO.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC3046099&req=5

f6-0040240: The Mg2+-sensitive Socs3a pathway is involved in the proliferative defect of the swd mutants. Supplementary Mg2+ improves the exocrine pancreas phenotype of the swd mutants that have repression of socs3a. (A) swdp75fm mutants were incubated in E3 medium with or without supplementary 40 mM MgCl2 for 72 or 96 hpf and analyzed for socs3a mRNA by real-time PCR. (B) swdp75fm mutants and WT were incubated in E3 medium (containing 1.65 mM Mg2+) for 72 or 96 hpf, and the socs3a mRNA levels were determined by real-time PCR. (C) Embryos collected from swdp75fm/+ intercross were microinjected with socs3a-ATG-MO or control MO, incubated until 4 dpf and the exocrine pancreas (red arrows) was analyzed by whole-mount in situ hybridization using anti-trypsin riboprobes. The image is representative of 20 larvae in each group from three independent experiments. The swdp75fm mutants injected with either non-targeting control MO or socs3a-5-mispair MO are indistinguishable in the exocrine pancreas by in situ hybridization using anti-trypsin riboprobes. (D) socs3a-ATG-MO- or control-MO-injected larvae were incubated until 72 hpf, injected with BrdU and then analyzed for the proportion of cells in S phase (% BrdU+ nuclei). (E) socs3a-ATG-MO- or control-MO-injected larvae were incubated until 96 hpf and analyzed for cell growth (area, in μm2, per cell). *P<0.05 indicates statistically significant difference. (C-E) The swdp75fm mutants were identified on the basis of their hypopigmented skin, which was not grossly affected by socs3a-ATG-MO.
Mentions: To gain insight into the mechanism by which supplementary Mg2+ improves the exocrine pancreatic phenotype, the swdp75fm mutants and their WT siblings were incubated in the absence (–) or presence (+) of added 40 mM MgCl2 and analyzed by transcriptional profiling. In the swdp75fm mutants (+Mg2+), expression of the negative modulator of epidermal growth factor (Egf)-induced proliferation, socs3a, was downregulated by 187% as compared with the swdp75fm mutants (–Mg2+) (supplementary material Table S2A, gene #5), and this was confirmed by real-time PCR (Fig. 6A). Similarly, the socs3a mRNA level was repressed by supplementary Mg2+ in the trpm7b508 mutants, as compared with that in the trpm7b508 mutants incubated without supplementary Mg2+ (supplementary material Fig. S1E). Expression of socs3a was verified to be upregulated in the swdp75fm mutants and trpm7b508 mutants relative to WT (all incubated in E3 medium without supplementary Mg2+), as indicated by real-time PCR (Fig. 6B; supplementary material Table S3, Fig. S1E). These data strongly suggest that Mg2+-modulated expression of socs3a mRNA is involved in the proliferative effect of Trpm7.

Bottom Line: The role of Socs3a in Trpm7-mediated signaling is supported by the findings that socs3a mRNA level is elevated in the trpm7 mutants, and antisense inhibition of socs3a expression improved their exocrine pancreatic growth.TRPM7 is generally overexpressed in human pancreatic adenocarcinoma.Results of this study indicate that Trpm7 regulates exocrine pancreatic development via the Mg(2+)-sensitive Socs3a pathway, and suggest that aberrant TRPM7-mediated signaling contributes to pancreatic carcinogenesis.

View Article: PubMed Central - PubMed

Affiliation: Division of Hematology, Oncology, and Blood & Marrow Transplantation, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA. nelson-yee@uiowa.edu

ABSTRACT
Genetic analysis of pancreatic development has provided new insights into the mechanisms underlying the formation of exocrine pancreatic neoplasia. Zebrafish sweetbread (swd) mutants develop hypoplastic acini and dysmorphic ducts in the exocrine pancreas, with impeded progression of cell division cycle and of epithelial growth. Positional cloning and allelic complementation have revealed that the swd mutations affect the transient receptor potential melastatin-subfamily member 7 (trpm7) gene, which encodes a divalent cation-permeable channel with kinase activity. Supplementary Mg(2+) partially rescued the exocrine pancreatic defects of the trpm7 mutants by improving cell-cycle progression and growth and repressing the suppressor of cytokine signaling 3a (socs3a) gene. The role of Socs3a in Trpm7-mediated signaling is supported by the findings that socs3a mRNA level is elevated in the trpm7 mutants, and antisense inhibition of socs3a expression improved their exocrine pancreatic growth. TRPM7 is generally overexpressed in human pancreatic adenocarcinoma. TRPM7-deficient cells are impaired in proliferation and arrested in the G0-G1 phases of the cell division cycle. Supplementary Mg(2+) rescued the proliferative defect of the TRPM7-deficient cells. Results of this study indicate that Trpm7 regulates exocrine pancreatic development via the Mg(2+)-sensitive Socs3a pathway, and suggest that aberrant TRPM7-mediated signaling contributes to pancreatic carcinogenesis.

Show MeSH
Related in: MedlinePlus