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The inactivation of Arx in pancreatic α-cells triggers their neogenesis and conversion into functional β-like cells.

Courtney M, Gjernes E, Druelle N, Ravaud C, Vieira A, Ben-Othman N, Pfeifer A, Avolio F, Leuckx G, Lacas-Gervais S, Burel-Vandenbos F, Ambrosetti D, Hecksher-Sorensen J, Ravassard P, Heimberg H, Mansouri A, Collombat P - PLoS Genet. (2013)

Bottom Line: Of interest, through the generation and analysis of Arx and Pax4 conditional double-mutants, we provide evidence that Pax4 is dispensable for these regeneration processes, indicating that Arx represents the main trigger of α-cell-mediated β-like cell neogenesis.Importantly, the loss of Arx in α-cells is sufficient to regenerate a functional β-cell mass and thereby reverse diabetes following toxin-induced β-cell depletion.Our data therefore suggest that strategies aiming at inhibiting the expression of Arx, or its molecular targets/co-factors, may pave new avenues for the treatment of diabetes.

View Article: PubMed Central - PubMed

Affiliation: Université de Nice Sophia Antipolis, iBV, UMR 7277, Nice, France ; Inserm, iBV, U1091, Nice, France ; CNRS, iBV, UMR 7277, Nice, France.

ABSTRACT
Recently, it was demonstrated that pancreatic new-born glucagon-producing cells can regenerate and convert into insulin-producing β-like cells through the ectopic expression of a single gene, Pax4. Here, combining conditional loss-of-function and lineage tracing approaches, we show that the selective inhibition of the Arx gene in α-cells is sufficient to promote the conversion of adult α-cells into β-like cells at any age. Interestingly, this conversion induces the continuous mobilization of duct-lining precursor cells to adopt an endocrine cell fate, the glucagon(+) cells thereby generated being subsequently converted into β-like cells upon Arx inhibition. Of interest, through the generation and analysis of Arx and Pax4 conditional double-mutants, we provide evidence that Pax4 is dispensable for these regeneration processes, indicating that Arx represents the main trigger of α-cell-mediated β-like cell neogenesis. Importantly, the loss of Arx in α-cells is sufficient to regenerate a functional β-cell mass and thereby reverse diabetes following toxin-induced β-cell depletion. Our data therefore suggest that strategies aiming at inhibiting the expression of Arx, or its molecular targets/co-factors, may pave new avenues for the treatment of diabetes.

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Related in: MedlinePlus

The loss of Arx triggered in glucagon-producing cells induces an insulin+ cell hyperplasia, such cells expressing bona fide β-cell marker genes.Representative photographs of immunohistochemical analyses performed on pancreas sections of 7 month-old WT controls (A–B, G–H, M–N, S–T, Y–Z) and on age-/sex-matched Glu-ArxKO (C–D, I–J, O–P, U–V, Z1–Z2), as well as on IndGlu-ArxKO mice treated with Dox for 5 months (E–F, K–L, Q–R, W–X, Z3–Z4) using the indicated antibody combinations. Compared to controls, both mutant pancreata displayed an increase in islet size caused by an insulin+ cell hyperplasia, such cells uniformly expressing the bona fide β-cell markers Pax4 (A–F), PC1/3 (G–L), Glut-2 (M–R), Pdx1 (S–X), Nkx6.1 (Y–Z4), but also MafA, NeuroD1, HB9, and Pax6 (Figure S4). (Each photograph is representative of at least three independent animals).
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pgen-1003934-g002: The loss of Arx triggered in glucagon-producing cells induces an insulin+ cell hyperplasia, such cells expressing bona fide β-cell marker genes.Representative photographs of immunohistochemical analyses performed on pancreas sections of 7 month-old WT controls (A–B, G–H, M–N, S–T, Y–Z) and on age-/sex-matched Glu-ArxKO (C–D, I–J, O–P, U–V, Z1–Z2), as well as on IndGlu-ArxKO mice treated with Dox for 5 months (E–F, K–L, Q–R, W–X, Z3–Z4) using the indicated antibody combinations. Compared to controls, both mutant pancreata displayed an increase in islet size caused by an insulin+ cell hyperplasia, such cells uniformly expressing the bona fide β-cell markers Pax4 (A–F), PC1/3 (G–L), Glut-2 (M–R), Pdx1 (S–X), Nkx6.1 (Y–Z4), but also MafA, NeuroD1, HB9, and Pax6 (Figure S4). (Each photograph is representative of at least three independent animals).

Mentions: To ascertain the identity of the insulin+ cells in Glu-ArxKO and Dox+ IndGlu-ArxKO pancreata, we assayed the expression of several endocrine cell marker genes. Our analyses demonstrated that all insulin+ cells observed in Glu-ArxKO and Dox+ IndGlu-ArxKO pancreata expressed the bona fide β-cell labels Pax4 (Figure 2A–F), PC1/3 (Figure 2G–L), Glut-2 (Figure 2M–R), Pdx1 (Figure 2S–X), Nkx6.1 (Figure 2Y–Z4), MafA (Figure S4A–F), NeuroD1 (Figure S4G–L), HB9 (Figure S4M–R), and the pan-endocrine marker Pax6 (Figure S4S–X). These were found to lack the α-cell determinants, such as Brn-4 and glucagon, as well as somatostatin or PP (see hereafter and data not shown).


The inactivation of Arx in pancreatic α-cells triggers their neogenesis and conversion into functional β-like cells.

Courtney M, Gjernes E, Druelle N, Ravaud C, Vieira A, Ben-Othman N, Pfeifer A, Avolio F, Leuckx G, Lacas-Gervais S, Burel-Vandenbos F, Ambrosetti D, Hecksher-Sorensen J, Ravassard P, Heimberg H, Mansouri A, Collombat P - PLoS Genet. (2013)

The loss of Arx triggered in glucagon-producing cells induces an insulin+ cell hyperplasia, such cells expressing bona fide β-cell marker genes.Representative photographs of immunohistochemical analyses performed on pancreas sections of 7 month-old WT controls (A–B, G–H, M–N, S–T, Y–Z) and on age-/sex-matched Glu-ArxKO (C–D, I–J, O–P, U–V, Z1–Z2), as well as on IndGlu-ArxKO mice treated with Dox for 5 months (E–F, K–L, Q–R, W–X, Z3–Z4) using the indicated antibody combinations. Compared to controls, both mutant pancreata displayed an increase in islet size caused by an insulin+ cell hyperplasia, such cells uniformly expressing the bona fide β-cell markers Pax4 (A–F), PC1/3 (G–L), Glut-2 (M–R), Pdx1 (S–X), Nkx6.1 (Y–Z4), but also MafA, NeuroD1, HB9, and Pax6 (Figure S4). (Each photograph is representative of at least three independent animals).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3814322&req=5

pgen-1003934-g002: The loss of Arx triggered in glucagon-producing cells induces an insulin+ cell hyperplasia, such cells expressing bona fide β-cell marker genes.Representative photographs of immunohistochemical analyses performed on pancreas sections of 7 month-old WT controls (A–B, G–H, M–N, S–T, Y–Z) and on age-/sex-matched Glu-ArxKO (C–D, I–J, O–P, U–V, Z1–Z2), as well as on IndGlu-ArxKO mice treated with Dox for 5 months (E–F, K–L, Q–R, W–X, Z3–Z4) using the indicated antibody combinations. Compared to controls, both mutant pancreata displayed an increase in islet size caused by an insulin+ cell hyperplasia, such cells uniformly expressing the bona fide β-cell markers Pax4 (A–F), PC1/3 (G–L), Glut-2 (M–R), Pdx1 (S–X), Nkx6.1 (Y–Z4), but also MafA, NeuroD1, HB9, and Pax6 (Figure S4). (Each photograph is representative of at least three independent animals).
Mentions: To ascertain the identity of the insulin+ cells in Glu-ArxKO and Dox+ IndGlu-ArxKO pancreata, we assayed the expression of several endocrine cell marker genes. Our analyses demonstrated that all insulin+ cells observed in Glu-ArxKO and Dox+ IndGlu-ArxKO pancreata expressed the bona fide β-cell labels Pax4 (Figure 2A–F), PC1/3 (Figure 2G–L), Glut-2 (Figure 2M–R), Pdx1 (Figure 2S–X), Nkx6.1 (Figure 2Y–Z4), MafA (Figure S4A–F), NeuroD1 (Figure S4G–L), HB9 (Figure S4M–R), and the pan-endocrine marker Pax6 (Figure S4S–X). These were found to lack the α-cell determinants, such as Brn-4 and glucagon, as well as somatostatin or PP (see hereafter and data not shown).

Bottom Line: Of interest, through the generation and analysis of Arx and Pax4 conditional double-mutants, we provide evidence that Pax4 is dispensable for these regeneration processes, indicating that Arx represents the main trigger of α-cell-mediated β-like cell neogenesis.Importantly, the loss of Arx in α-cells is sufficient to regenerate a functional β-cell mass and thereby reverse diabetes following toxin-induced β-cell depletion.Our data therefore suggest that strategies aiming at inhibiting the expression of Arx, or its molecular targets/co-factors, may pave new avenues for the treatment of diabetes.

View Article: PubMed Central - PubMed

Affiliation: Université de Nice Sophia Antipolis, iBV, UMR 7277, Nice, France ; Inserm, iBV, U1091, Nice, France ; CNRS, iBV, UMR 7277, Nice, France.

ABSTRACT
Recently, it was demonstrated that pancreatic new-born glucagon-producing cells can regenerate and convert into insulin-producing β-like cells through the ectopic expression of a single gene, Pax4. Here, combining conditional loss-of-function and lineage tracing approaches, we show that the selective inhibition of the Arx gene in α-cells is sufficient to promote the conversion of adult α-cells into β-like cells at any age. Interestingly, this conversion induces the continuous mobilization of duct-lining precursor cells to adopt an endocrine cell fate, the glucagon(+) cells thereby generated being subsequently converted into β-like cells upon Arx inhibition. Of interest, through the generation and analysis of Arx and Pax4 conditional double-mutants, we provide evidence that Pax4 is dispensable for these regeneration processes, indicating that Arx represents the main trigger of α-cell-mediated β-like cell neogenesis. Importantly, the loss of Arx in α-cells is sufficient to regenerate a functional β-cell mass and thereby reverse diabetes following toxin-induced β-cell depletion. Our data therefore suggest that strategies aiming at inhibiting the expression of Arx, or its molecular targets/co-factors, may pave new avenues for the treatment of diabetes.

Show MeSH
Related in: MedlinePlus