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Compensatory Response by Late Embryonic Tubular Epithelium to the Reduction in Pancreatic Progenitors.

Nishimura W, Kapoor A, El Khattabi I, Jin W, Yasuda K, Bonner-Weir S, Sharma A - PLoS ONE (2015)

Bottom Line: Previously we reported that in Pdx1tTA/+;tetOMafA (bigenic) mice inducing expression of transcription factor MafA in Pdx1-expressing (Pdx1+) cells throughout embryonic development inhibited the proliferation and differentiation of 1°MPC cells, resulting in reduced pancreatic mass and endocrine cells by embryonic day (E) 17.5.However, by birth (P0), as we now report, such bigenic pups had significantly increased pancreatic and endocrine volumes with endocrine clusters containing all pancreatic endocrine cell types.Thus, these bigenic mice provide a novel way to characterize the competency of 1°MPC for their ability to specify endocrine progenitors, a critical limitation in our understanding of endocrine differentiation.

View Article: PubMed Central - PubMed

Affiliation: Section of Islet Cell & Regenerative Biology, Joslin Diabetes Center, Boston, Massachusetts, United States of America.

ABSTRACT
Early in pancreatic development, epithelial cells of pancreatic buds function as primary multipotent progenitor cells (1°MPC) that specify all three pancreatic cell lineages, i.e., endocrine, acinar and duct. Bipotent "Trunk" progenitors derived from 1°MPC are implicated in directly regulating the specification of endocrine progenitors. It is unclear if this specification process is initiated in the 1°MPC where some 1°MPC become competent for later specification of endocrine progenitors. Previously we reported that in Pdx1tTA/+;tetOMafA (bigenic) mice inducing expression of transcription factor MafA in Pdx1-expressing (Pdx1+) cells throughout embryonic development inhibited the proliferation and differentiation of 1°MPC cells, resulting in reduced pancreatic mass and endocrine cells by embryonic day (E) 17.5. Induction of the transgene only until E12.5 in Pdx1+ 1°MPC was sufficient for this inhibition of endocrine cells and pancreatic mass at E17.5. However, by birth (P0), as we now report, such bigenic pups had significantly increased pancreatic and endocrine volumes with endocrine clusters containing all pancreatic endocrine cell types. The increase in endocrine cells resulted from a higher proliferation of tubular epithelial cells expressing the progenitor marker Glut2 in E17.5 bigenic embryos and increased number of Neurog3-expressing cells at E19.5. A BrdU-labeling study demonstrated that inhibiting proliferation of 1°MPC by forced MafA-expression did not lead to retention of those progenitors in E17.5 tubular epithelium. Our data suggest that the forced MafA expression in the 1°MPC inhibits their competency to specify endocrine progenitors only until E17.5, and after that compensatory proliferation of tubular epithelium gives rise to a distinct pool of endocrine progenitors. Thus, these bigenic mice provide a novel way to characterize the competency of 1°MPC for their ability to specify endocrine progenitors, a critical limitation in our understanding of endocrine differentiation.

No MeSH data available.


Related in: MedlinePlus

Tubular epithelial cells of bigenic pancreas express Sox9 and GLUT2 at E17.5.At E17.5 both control and bigenic tubular epithelial cells express Sox9. Sox9 (green AB); DBA (green, CD); GLUT2 (green, EF); Insulin (red); DAPI (blue). The boxed areas in E and F are enlarged (GH: merged channels, IJ: green channel showing GLUT2 expression). Higher GLUT2 staining intensity is seen in the bigenic tubular epithelial cells than in the controls. In bigenic pancreas GLUT2 staining intensity is comparable in insulin+ (marked by arrows) and insulin- tubular epithelial cells (marked by arrowheads) whereas in control pancreas GLUT2 staining intensity is reduced in tubular epithelial cells than islets. Bar: 20 μm.
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pone.0142286.g007: Tubular epithelial cells of bigenic pancreas express Sox9 and GLUT2 at E17.5.At E17.5 both control and bigenic tubular epithelial cells express Sox9. Sox9 (green AB); DBA (green, CD); GLUT2 (green, EF); Insulin (red); DAPI (blue). The boxed areas in E and F are enlarged (GH: merged channels, IJ: green channel showing GLUT2 expression). Higher GLUT2 staining intensity is seen in the bigenic tubular epithelial cells than in the controls. In bigenic pancreas GLUT2 staining intensity is comparable in insulin+ (marked by arrows) and insulin- tubular epithelial cells (marked by arrowheads) whereas in control pancreas GLUT2 staining intensity is reduced in tubular epithelial cells than islets. Bar: 20 μm.

Mentions: The expression of progenitor markers Sox9 and GLUT2 were examined to evaluate the enhanced neogeneic capacity of E17.5 DBA+ tubular cells in bigenic pancreas. Sox9 was expressed in the DBA+ tubular epithelial cells of both bigenic and control pancreas (Fig 7A–7D). Early in pancreatic development, GLUT2 expression marks the multipotent progenitors [23]. However, by E17 when the fate of tubular epithelial cells is becoming restricted to ducts, most of these cells lack Glut2 expression, except those that co-express insulin [23, 24]. Consistent with these published results, in E17.5 control pancreas GLUT2 expression in tubular epithelium was significantly reduced compared to the high GLUT2 expression in insulin+ cells (Fig 7F, 7H and 7J). However, Glut2 expression in DBA+ cells in Pdx1tTA/+;tetOMafA pancreas was higher than in controls, and comparable to that in the rare insulin+ cells seen in these bigenic pancreases (Fig 7E, 7G and 7I). This higher expression of Glut2 in DBA+ tubular epithelium of E17.5 bigenic pancreas suggests that these cells retain the progenitor potential to proliferate and differentiate into other pancreatic cell types.


Compensatory Response by Late Embryonic Tubular Epithelium to the Reduction in Pancreatic Progenitors.

Nishimura W, Kapoor A, El Khattabi I, Jin W, Yasuda K, Bonner-Weir S, Sharma A - PLoS ONE (2015)

Tubular epithelial cells of bigenic pancreas express Sox9 and GLUT2 at E17.5.At E17.5 both control and bigenic tubular epithelial cells express Sox9. Sox9 (green AB); DBA (green, CD); GLUT2 (green, EF); Insulin (red); DAPI (blue). The boxed areas in E and F are enlarged (GH: merged channels, IJ: green channel showing GLUT2 expression). Higher GLUT2 staining intensity is seen in the bigenic tubular epithelial cells than in the controls. In bigenic pancreas GLUT2 staining intensity is comparable in insulin+ (marked by arrows) and insulin- tubular epithelial cells (marked by arrowheads) whereas in control pancreas GLUT2 staining intensity is reduced in tubular epithelial cells than islets. Bar: 20 μm.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4635002&req=5

pone.0142286.g007: Tubular epithelial cells of bigenic pancreas express Sox9 and GLUT2 at E17.5.At E17.5 both control and bigenic tubular epithelial cells express Sox9. Sox9 (green AB); DBA (green, CD); GLUT2 (green, EF); Insulin (red); DAPI (blue). The boxed areas in E and F are enlarged (GH: merged channels, IJ: green channel showing GLUT2 expression). Higher GLUT2 staining intensity is seen in the bigenic tubular epithelial cells than in the controls. In bigenic pancreas GLUT2 staining intensity is comparable in insulin+ (marked by arrows) and insulin- tubular epithelial cells (marked by arrowheads) whereas in control pancreas GLUT2 staining intensity is reduced in tubular epithelial cells than islets. Bar: 20 μm.
Mentions: The expression of progenitor markers Sox9 and GLUT2 were examined to evaluate the enhanced neogeneic capacity of E17.5 DBA+ tubular cells in bigenic pancreas. Sox9 was expressed in the DBA+ tubular epithelial cells of both bigenic and control pancreas (Fig 7A–7D). Early in pancreatic development, GLUT2 expression marks the multipotent progenitors [23]. However, by E17 when the fate of tubular epithelial cells is becoming restricted to ducts, most of these cells lack Glut2 expression, except those that co-express insulin [23, 24]. Consistent with these published results, in E17.5 control pancreas GLUT2 expression in tubular epithelium was significantly reduced compared to the high GLUT2 expression in insulin+ cells (Fig 7F, 7H and 7J). However, Glut2 expression in DBA+ cells in Pdx1tTA/+;tetOMafA pancreas was higher than in controls, and comparable to that in the rare insulin+ cells seen in these bigenic pancreases (Fig 7E, 7G and 7I). This higher expression of Glut2 in DBA+ tubular epithelium of E17.5 bigenic pancreas suggests that these cells retain the progenitor potential to proliferate and differentiate into other pancreatic cell types.

Bottom Line: Previously we reported that in Pdx1tTA/+;tetOMafA (bigenic) mice inducing expression of transcription factor MafA in Pdx1-expressing (Pdx1+) cells throughout embryonic development inhibited the proliferation and differentiation of 1°MPC cells, resulting in reduced pancreatic mass and endocrine cells by embryonic day (E) 17.5.However, by birth (P0), as we now report, such bigenic pups had significantly increased pancreatic and endocrine volumes with endocrine clusters containing all pancreatic endocrine cell types.Thus, these bigenic mice provide a novel way to characterize the competency of 1°MPC for their ability to specify endocrine progenitors, a critical limitation in our understanding of endocrine differentiation.

View Article: PubMed Central - PubMed

Affiliation: Section of Islet Cell & Regenerative Biology, Joslin Diabetes Center, Boston, Massachusetts, United States of America.

ABSTRACT
Early in pancreatic development, epithelial cells of pancreatic buds function as primary multipotent progenitor cells (1°MPC) that specify all three pancreatic cell lineages, i.e., endocrine, acinar and duct. Bipotent "Trunk" progenitors derived from 1°MPC are implicated in directly regulating the specification of endocrine progenitors. It is unclear if this specification process is initiated in the 1°MPC where some 1°MPC become competent for later specification of endocrine progenitors. Previously we reported that in Pdx1tTA/+;tetOMafA (bigenic) mice inducing expression of transcription factor MafA in Pdx1-expressing (Pdx1+) cells throughout embryonic development inhibited the proliferation and differentiation of 1°MPC cells, resulting in reduced pancreatic mass and endocrine cells by embryonic day (E) 17.5. Induction of the transgene only until E12.5 in Pdx1+ 1°MPC was sufficient for this inhibition of endocrine cells and pancreatic mass at E17.5. However, by birth (P0), as we now report, such bigenic pups had significantly increased pancreatic and endocrine volumes with endocrine clusters containing all pancreatic endocrine cell types. The increase in endocrine cells resulted from a higher proliferation of tubular epithelial cells expressing the progenitor marker Glut2 in E17.5 bigenic embryos and increased number of Neurog3-expressing cells at E19.5. A BrdU-labeling study demonstrated that inhibiting proliferation of 1°MPC by forced MafA-expression did not lead to retention of those progenitors in E17.5 tubular epithelium. Our data suggest that the forced MafA expression in the 1°MPC inhibits their competency to specify endocrine progenitors only until E17.5, and after that compensatory proliferation of tubular epithelium gives rise to a distinct pool of endocrine progenitors. Thus, these bigenic mice provide a novel way to characterize the competency of 1°MPC for their ability to specify endocrine progenitors, a critical limitation in our understanding of endocrine differentiation.

No MeSH data available.


Related in: MedlinePlus