Limits...
PAX4 Defines an Expandable β-Cell Subpopulation in the Adult Pancreatic Islet.

Lorenzo PI, Fuente-Martín E, Brun T, Cobo-Vuilleumier N, Jimenez-Moreno CM, G Herrera Gomez I, López Noriega L, Mellado-Gil JM, Martin-Montalvo A, Soria B, Gauthier BR - Sci Rep (2015)

Bottom Line: Lineage tracing demonstrated that all islet cells were derived from PAX4(+) progenitor cells but that GFP expression was confined to a subpopulation at birth which declined with age correlating with reduced replication.Under stress conditions, GFP(+) cells were more resistant to apoptosis than their GFP(-) counterparts.Our data suggest PAX4 defines an expandable β-cell sub population within adult islets.

View Article: PubMed Central - PubMed

Affiliation: Pancreatic Islet Development and Regeneration Unit, Department of Stem Cells, CABIMER-Andalusian Center for Molecular Biology and Regenerative Medicine, Seville, Spain.

ABSTRACT
PAX4 is a key regulator of pancreatic islet development whilst in adult acute overexpression protects β-cells against stress-induced apoptosis and stimulates proliferation. Nonetheless, sustained PAX4 expression promotes β-cell dedifferentiation and hyperglycemia, mimicking β-cell failure in diabetic patients. Herein, we study mechanisms that allow stringent PAX4 regulation endowing favorable β-cell adaptation in response to changing environment without loss of identity. To this end, PAX4 expression was monitored using a mouse bearing the enhanced green fluorescent protein (GFP) and cre recombinase construct under the control of the islet specific pax4 promoter. GFP was detected in 30% of islet cells predominantly composed of PAX4-enriched β-cells that responded to glucose-induced insulin secretion. Lineage tracing demonstrated that all islet cells were derived from PAX4(+) progenitor cells but that GFP expression was confined to a subpopulation at birth which declined with age correlating with reduced replication. However, this GFP(+) subpopulation expanded during pregnancy, a state of active β-cell replication. Accordingly, enhanced proliferation was exclusively detected in GFP(+) cells consistent with cell cycle genes being stimulated in PAX4-overexpressing islets. Under stress conditions, GFP(+) cells were more resistant to apoptosis than their GFP(-) counterparts. Our data suggest PAX4 defines an expandable β-cell sub population within adult islets.

No MeSH data available.


Related in: MedlinePlus

GFP expression predominantly co-localizes with insulin-producing β-cells in adult islets.(a) Immunohistochemistry analysis of paraffin sections from adult pPax4-Cre-IRES-Egfp mice pancreas. Representative microscopy images for co-immunofluorescent labeling of GFP (green) together with E-CADHERIN (for cellular delimitation) or with the pancreatic islet cell markers INSULIN (red), GLUCAGON (red) or SOMATOSTATIN (red). Nuclei counterstaining was performed using DAPI (blue). (b) Quantitative analysis (average ± SE) of the GFP+ cell population composition. (c) Quantification of the percentage of INSULIN+, GLUCAGON+ and SOMATOSTATIN+ cells that co-express GFP (average ± SE). Sections (2 to 4) from 3 to 5 independent animals with an average of 15 islets and 1400 cells per animal were used for quantifications.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4622080&req=5

f2: GFP expression predominantly co-localizes with insulin-producing β-cells in adult islets.(a) Immunohistochemistry analysis of paraffin sections from adult pPax4-Cre-IRES-Egfp mice pancreas. Representative microscopy images for co-immunofluorescent labeling of GFP (green) together with E-CADHERIN (for cellular delimitation) or with the pancreatic islet cell markers INSULIN (red), GLUCAGON (red) or SOMATOSTATIN (red). Nuclei counterstaining was performed using DAPI (blue). (b) Quantitative analysis (average ± SE) of the GFP+ cell population composition. (c) Quantification of the percentage of INSULIN+, GLUCAGON+ and SOMATOSTATIN+ cells that co-express GFP (average ± SE). Sections (2 to 4) from 3 to 5 independent animals with an average of 15 islets and 1400 cells per animal were used for quantifications.

Mentions: To assess in more detail the spatial distribution as well as to determine the specific cell types expressing GFP within islets, we performed immunohistochemistry analysis of pancreas sections derived from pPax4-Cre-IRES-Egfp adult mice (Fig. 2). Co-immunostaining using an antibody against the cell membrane protein E-CADHERIN along with an anti-GFP sera, clearly established the presence of a GFP/PAX4+cell subset randomly distributed within islets (Fig. 2a). Analysis of GFP co-expression with markers of different islet cell types revealed that more than 90% of the GFP/PAX4+ subpopulation were insulin-expressing cells (Fig. 2a,b) and comprised approximately 30% of the total β-cell population (Fig. 2c). However, 3.73 ± 1.32% and 5.31 ± 1.80% of GFP/PAX4+ cells co-immunostained for GLUCAGON and SOMATOSTATIN respectively (Fig. 2a,b), representing roughly 6% and 10% of the total α- and δ-cell populations (Fig. 2c).


PAX4 Defines an Expandable β-Cell Subpopulation in the Adult Pancreatic Islet.

Lorenzo PI, Fuente-Martín E, Brun T, Cobo-Vuilleumier N, Jimenez-Moreno CM, G Herrera Gomez I, López Noriega L, Mellado-Gil JM, Martin-Montalvo A, Soria B, Gauthier BR - Sci Rep (2015)

GFP expression predominantly co-localizes with insulin-producing β-cells in adult islets.(a) Immunohistochemistry analysis of paraffin sections from adult pPax4-Cre-IRES-Egfp mice pancreas. Representative microscopy images for co-immunofluorescent labeling of GFP (green) together with E-CADHERIN (for cellular delimitation) or with the pancreatic islet cell markers INSULIN (red), GLUCAGON (red) or SOMATOSTATIN (red). Nuclei counterstaining was performed using DAPI (blue). (b) Quantitative analysis (average ± SE) of the GFP+ cell population composition. (c) Quantification of the percentage of INSULIN+, GLUCAGON+ and SOMATOSTATIN+ cells that co-express GFP (average ± SE). Sections (2 to 4) from 3 to 5 independent animals with an average of 15 islets and 1400 cells per animal were used for quantifications.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4622080&req=5

f2: GFP expression predominantly co-localizes with insulin-producing β-cells in adult islets.(a) Immunohistochemistry analysis of paraffin sections from adult pPax4-Cre-IRES-Egfp mice pancreas. Representative microscopy images for co-immunofluorescent labeling of GFP (green) together with E-CADHERIN (for cellular delimitation) or with the pancreatic islet cell markers INSULIN (red), GLUCAGON (red) or SOMATOSTATIN (red). Nuclei counterstaining was performed using DAPI (blue). (b) Quantitative analysis (average ± SE) of the GFP+ cell population composition. (c) Quantification of the percentage of INSULIN+, GLUCAGON+ and SOMATOSTATIN+ cells that co-express GFP (average ± SE). Sections (2 to 4) from 3 to 5 independent animals with an average of 15 islets and 1400 cells per animal were used for quantifications.
Mentions: To assess in more detail the spatial distribution as well as to determine the specific cell types expressing GFP within islets, we performed immunohistochemistry analysis of pancreas sections derived from pPax4-Cre-IRES-Egfp adult mice (Fig. 2). Co-immunostaining using an antibody against the cell membrane protein E-CADHERIN along with an anti-GFP sera, clearly established the presence of a GFP/PAX4+cell subset randomly distributed within islets (Fig. 2a). Analysis of GFP co-expression with markers of different islet cell types revealed that more than 90% of the GFP/PAX4+ subpopulation were insulin-expressing cells (Fig. 2a,b) and comprised approximately 30% of the total β-cell population (Fig. 2c). However, 3.73 ± 1.32% and 5.31 ± 1.80% of GFP/PAX4+ cells co-immunostained for GLUCAGON and SOMATOSTATIN respectively (Fig. 2a,b), representing roughly 6% and 10% of the total α- and δ-cell populations (Fig. 2c).

Bottom Line: Lineage tracing demonstrated that all islet cells were derived from PAX4(+) progenitor cells but that GFP expression was confined to a subpopulation at birth which declined with age correlating with reduced replication.Under stress conditions, GFP(+) cells were more resistant to apoptosis than their GFP(-) counterparts.Our data suggest PAX4 defines an expandable β-cell sub population within adult islets.

View Article: PubMed Central - PubMed

Affiliation: Pancreatic Islet Development and Regeneration Unit, Department of Stem Cells, CABIMER-Andalusian Center for Molecular Biology and Regenerative Medicine, Seville, Spain.

ABSTRACT
PAX4 is a key regulator of pancreatic islet development whilst in adult acute overexpression protects β-cells against stress-induced apoptosis and stimulates proliferation. Nonetheless, sustained PAX4 expression promotes β-cell dedifferentiation and hyperglycemia, mimicking β-cell failure in diabetic patients. Herein, we study mechanisms that allow stringent PAX4 regulation endowing favorable β-cell adaptation in response to changing environment without loss of identity. To this end, PAX4 expression was monitored using a mouse bearing the enhanced green fluorescent protein (GFP) and cre recombinase construct under the control of the islet specific pax4 promoter. GFP was detected in 30% of islet cells predominantly composed of PAX4-enriched β-cells that responded to glucose-induced insulin secretion. Lineage tracing demonstrated that all islet cells were derived from PAX4(+) progenitor cells but that GFP expression was confined to a subpopulation at birth which declined with age correlating with reduced replication. However, this GFP(+) subpopulation expanded during pregnancy, a state of active β-cell replication. Accordingly, enhanced proliferation was exclusively detected in GFP(+) cells consistent with cell cycle genes being stimulated in PAX4-overexpressing islets. Under stress conditions, GFP(+) cells were more resistant to apoptosis than their GFP(-) counterparts. Our data suggest PAX4 defines an expandable β-cell sub population within adult islets.

No MeSH data available.


Related in: MedlinePlus