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Injury-stimulated Hedgehog signaling promotes regenerative proliferation of Drosophila intestinal stem cells.

Tian A, Shi Q, Jiang A, Li S, Wang B, Jiang J - J. Cell Biol. (2015)

Bottom Line: Inhibition of Hh signaling in the ISC lineage compromised injury-induced ISC proliferation but had little if any effect on homeostatic proliferation.Furthermore, we show that Hh signaling is stimulated by DSS through the JNK pathway and that inhibition of Hh signaling in EBs prevented DSS-stimulated ISC proliferation.Hence, our study uncovers a JNK-Hh-JAK-STAT signaling axis in the regulation of regenerative stem cell proliferation.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Developmental Biology and Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390.

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Hh signaling is up-regulated by DSS-mediated tissue damage. (A) Quantification of hh and ptc mRNA levels by RT-qPCR in midguts treated with DSS or Suc for 1 d. Three independent experiments were performed and error bars are standard deviations. *, P < 0.05. (B–C′) Adult midguts expressing UAS-GFP under the control of hh-Gal4 (hh>GFP) were immunostained for GFP and DRAQ5 (B) or Pdm1 (C and C′). hh>GFP was mainly detected in Pdm1+ ECs. (D–E′) Adult midguts carrying two copies of hh-lacZ were immunostained for LacZ (D–E′) and Pdm1 (D and D′) or GFP under the control of esg-Gal4 (E and E′). (F–G″) Expression of one copy of hh-lacZ in midguts treated with Suc (F–F″) or DSS (G–G″) for 1 d. hh-lacZ was elevated in both ECs (large nuclei) and precursor cells (small nuclei) in response to DSS treatment. (H–I′) Expression of ptc-lacZ in control (Suc) and DSS-treated midguts for 1 d. ptc-lacZ was elevated in esg-GFP–positive cells after DSS treatment. (J and K) Quantification of hh mRNA levels by RT-qPCR (J) or PH3+ cells (K) in control, esgts>HhRNAi, or Myo1Ats>HhRNAi guts treated with Suc or DSS after adult flies were raised for 10 d at 29°C. Three independent experiments were performed, and error bars are standard deviations. 20 guts were examined for each sample in K. **, P < 0.01; *, P < 0.05. Bars, 50 µm.
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fig5: Hh signaling is up-regulated by DSS-mediated tissue damage. (A) Quantification of hh and ptc mRNA levels by RT-qPCR in midguts treated with DSS or Suc for 1 d. Three independent experiments were performed and error bars are standard deviations. *, P < 0.05. (B–C′) Adult midguts expressing UAS-GFP under the control of hh-Gal4 (hh>GFP) were immunostained for GFP and DRAQ5 (B) or Pdm1 (C and C′). hh>GFP was mainly detected in Pdm1+ ECs. (D–E′) Adult midguts carrying two copies of hh-lacZ were immunostained for LacZ (D–E′) and Pdm1 (D and D′) or GFP under the control of esg-Gal4 (E and E′). (F–G″) Expression of one copy of hh-lacZ in midguts treated with Suc (F–F″) or DSS (G–G″) for 1 d. hh-lacZ was elevated in both ECs (large nuclei) and precursor cells (small nuclei) in response to DSS treatment. (H–I′) Expression of ptc-lacZ in control (Suc) and DSS-treated midguts for 1 d. ptc-lacZ was elevated in esg-GFP–positive cells after DSS treatment. (J and K) Quantification of hh mRNA levels by RT-qPCR (J) or PH3+ cells (K) in control, esgts>HhRNAi, or Myo1Ats>HhRNAi guts treated with Suc or DSS after adult flies were raised for 10 d at 29°C. Three independent experiments were performed, and error bars are standard deviations. 20 guts were examined for each sample in K. **, P < 0.01; *, P < 0.05. Bars, 50 µm.

Mentions: The observation that Hh signaling is not essential for basal ISC proliferation but is required for damage-induced ISC proliferation prompted us to examine whether Hh pathway activity is up-regulated in response to injury. Using RT-qPCR, we found that the expression of the Hh pathway target gene ptc as well as hh itself was up-regulated in guts treated with DSS; however, expression of hh was not induced by bleomycin treatment (Fig. 5 A and Fig. S2).


Injury-stimulated Hedgehog signaling promotes regenerative proliferation of Drosophila intestinal stem cells.

Tian A, Shi Q, Jiang A, Li S, Wang B, Jiang J - J. Cell Biol. (2015)

Hh signaling is up-regulated by DSS-mediated tissue damage. (A) Quantification of hh and ptc mRNA levels by RT-qPCR in midguts treated with DSS or Suc for 1 d. Three independent experiments were performed and error bars are standard deviations. *, P < 0.05. (B–C′) Adult midguts expressing UAS-GFP under the control of hh-Gal4 (hh>GFP) were immunostained for GFP and DRAQ5 (B) or Pdm1 (C and C′). hh>GFP was mainly detected in Pdm1+ ECs. (D–E′) Adult midguts carrying two copies of hh-lacZ were immunostained for LacZ (D–E′) and Pdm1 (D and D′) or GFP under the control of esg-Gal4 (E and E′). (F–G″) Expression of one copy of hh-lacZ in midguts treated with Suc (F–F″) or DSS (G–G″) for 1 d. hh-lacZ was elevated in both ECs (large nuclei) and precursor cells (small nuclei) in response to DSS treatment. (H–I′) Expression of ptc-lacZ in control (Suc) and DSS-treated midguts for 1 d. ptc-lacZ was elevated in esg-GFP–positive cells after DSS treatment. (J and K) Quantification of hh mRNA levels by RT-qPCR (J) or PH3+ cells (K) in control, esgts>HhRNAi, or Myo1Ats>HhRNAi guts treated with Suc or DSS after adult flies were raised for 10 d at 29°C. Three independent experiments were performed, and error bars are standard deviations. 20 guts were examined for each sample in K. **, P < 0.01; *, P < 0.05. Bars, 50 µm.
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fig5: Hh signaling is up-regulated by DSS-mediated tissue damage. (A) Quantification of hh and ptc mRNA levels by RT-qPCR in midguts treated with DSS or Suc for 1 d. Three independent experiments were performed and error bars are standard deviations. *, P < 0.05. (B–C′) Adult midguts expressing UAS-GFP under the control of hh-Gal4 (hh>GFP) were immunostained for GFP and DRAQ5 (B) or Pdm1 (C and C′). hh>GFP was mainly detected in Pdm1+ ECs. (D–E′) Adult midguts carrying two copies of hh-lacZ were immunostained for LacZ (D–E′) and Pdm1 (D and D′) or GFP under the control of esg-Gal4 (E and E′). (F–G″) Expression of one copy of hh-lacZ in midguts treated with Suc (F–F″) or DSS (G–G″) for 1 d. hh-lacZ was elevated in both ECs (large nuclei) and precursor cells (small nuclei) in response to DSS treatment. (H–I′) Expression of ptc-lacZ in control (Suc) and DSS-treated midguts for 1 d. ptc-lacZ was elevated in esg-GFP–positive cells after DSS treatment. (J and K) Quantification of hh mRNA levels by RT-qPCR (J) or PH3+ cells (K) in control, esgts>HhRNAi, or Myo1Ats>HhRNAi guts treated with Suc or DSS after adult flies were raised for 10 d at 29°C. Three independent experiments were performed, and error bars are standard deviations. 20 guts were examined for each sample in K. **, P < 0.01; *, P < 0.05. Bars, 50 µm.
Mentions: The observation that Hh signaling is not essential for basal ISC proliferation but is required for damage-induced ISC proliferation prompted us to examine whether Hh pathway activity is up-regulated in response to injury. Using RT-qPCR, we found that the expression of the Hh pathway target gene ptc as well as hh itself was up-regulated in guts treated with DSS; however, expression of hh was not induced by bleomycin treatment (Fig. 5 A and Fig. S2).

Bottom Line: Inhibition of Hh signaling in the ISC lineage compromised injury-induced ISC proliferation but had little if any effect on homeostatic proliferation.Furthermore, we show that Hh signaling is stimulated by DSS through the JNK pathway and that inhibition of Hh signaling in EBs prevented DSS-stimulated ISC proliferation.Hence, our study uncovers a JNK-Hh-JAK-STAT signaling axis in the regulation of regenerative stem cell proliferation.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Developmental Biology and Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390.

Show MeSH
Related in: MedlinePlus