Activation of Smad2 but not Smad3 is required to mediate TGF-β signaling during axolotl limb regeneration

Denis, Jean-Emile; Sader, Fadi; Gatien, Samuel; Villiard, Éric; Philip, Anie; Roy, Stéphane

doi:10.1242/dev.131466

Cited by 35 publications

(53 citation statements)

References 82 publications

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“…To further investigate the role of SMADs in TGF‐β1 induced migration and MMP‐2/‐9 induction, we performed knockdown experiments in Schwann cells. We found that TGF‐β1‐induced MMP‐2 secretion was SMAD2‐dependent, in agreement with other studies (Piek et al, ; Meng et al, ; Denis et al, ). These results suggest that inhibition of the canonical TGF‐β1 pathway blocks cell migration and invasion by preventing the activation of SMAD2.…”

Section: Discussionsupporting

confidence: 93%

TGF‐β1 activates RSC96 Schwann cells migration and invasion through MMP‐2 and MMP‐9 activities

Muscella

Vetrugno

Cossa

et al. 2019

Journal of Neurochemistry

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Following peripheral nerve injury, remnant Schwann cells adopt a migratory phenotype and remodel the extracellular matrix allowing axonal regrowth. Although much evidence has demonstrated that TGF-b1 promotes glioma cell motility and induces the expression of extracellular matrix proteins, the effects of TGF-b1 on Schwann cell migration has not yet been studied. We therefore investigated the cellular effects and the signal transduction pathways evoked by TGF-b1 in rattus norvegicus neuronal Schwann RSC96 cell. TGF-b1 significantly increased migration and invasion of Schwann cells assessed by the wound-healing assay and by cell invasion assay. TGF-b1-enhanced migration/invasion was blocked by inhibition of MMP-2 and MMP-9. Consistently, by real-time and western blot analyses, we demonstrated that TGF-b1 increased MMP-2 and MMP-9 mRNA and protein levels. TGF-b1 also increased MMPs activities in cell growth medium, as shown by gelatin zymography. The selective TGF-b Type I receptor inhibitor SB431542 completely abrogated any effects by TGF-b1. Indeed, TGF-b1 Type I receptor activation provoked the cytosol-to-nucleus translocation of SMAD2 and SMAD3. SMAD2 knockdown by siRNA blocked MMP-2 induction and cell migration/invasion due to TGF-b1. TGF-b1 also provoked phosphorylation of MAPKs extracellular regulated kinase 1/2 and JNK1/2. Both MAPKs were upstream to p65/NF-kB inasmuch as both MAPKs' inhibitors PD98059 and SP600125 or their down-regulation by siRNA significantly blocked the TGF-b1-induced nuclear translocation of p65/NF-kB. In addition, p65/NF-jB siRNA knockdown inhibited the effects of TGF-b1 on both MMP-9 and cell migration/invasion. We conclude that TGF-b1 controls RSC96 Schwann cell migration and invasion through MMP-2 and MMP-9 activities. MMP-2 is controlled by SMAD2 whilst MMP-9 is controlled via an ERK1/2-JNK1/2-NF-jB dependent pathway. Abbreviations used: ERK1/2, extracellular regulated kinase 1/2; FBS, fetal bovine serum; MEK, MAPK/ERK kinase; MMP (2-9), matrix metalloproteinases (2-9); MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenol tetrazolium bromide; NF-kB, nuclear factor-kappa B; siRNAs, small interfering RNAs; SMAD (2-3), small mother against decapentaplegic (2-3); TGF-b, transforming growth factor beta.

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Section: Discussionsupporting

confidence: 93%

TGF‐β1 activates RSC96 Schwann cells migration and invasion through MMP‐2 and MMP‐9 activities

Muscella

Vetrugno

Cossa

et al. 2019

Journal of Neurochemistry

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“…As downstream effectors of all three pathways interact in development and tumorigenesis (McNeill and Woodgett, 2010; Attisano and Wrana, 2013), it is likely that synergy between these pathways is essential for early blastemal cell establishment and maintenance. Interestingly, TGF-β signaling, which is necessary for axolotl limb regeneration (Levesque et al, 2007;Denis et al, 2016), was specifically active in dividing cells. Our data further suggest that TGF-β signaling is sustained through autocrine feedback in early dividing cells, which exhibit exclusive upregulation of tgf-β1, tgf-β1r and smad-2, as well as regulators and direct targets, including ltbp1, twist1 and snail-1.…”

Section: Discussionmentioning

confidence: 99%

Blastemal progenitors modulate immune signaling during early limb regeneration

2019

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Blastema formation, a hallmark of limb regeneration, requires proliferation and migration of progenitors to the amputation plane. Although blastema formation has been well described, the transcriptional programs that drive blastemal progenitors remain unknown. We transcriptionally profiled dividing and non-dividing cells in regenerating stump tissues, as well as the wound epidermis, during early axolotl limb regeneration. Our analysis revealed unique transcriptional signatures of early dividing cells and, unexpectedly, repression of several core developmental signaling pathways in early regenerating stump tissues. We further identify an immunomodulatory role for blastemal progenitors through interleukin 8 (IL-8), a highly expressed cytokine in subpopulations of early blastemal progenitors. Ectopic il-8 expression in nonregenerating limbs induced myeloid cell recruitment, while IL-8 knockdown resulted in defective myeloid cell retention during late wound healing, delaying regeneration. Furthermore, the il-8 receptor cxcr-1/2 was expressed in myeloid cells, and inhibition of CXCR-1/2 signaling during early stages of limb regeneration prevented regeneration. Altogether, our findings suggest that blastemal progenitors are active early mediators of immune support, and identify CXCR-1/2 signaling as an important immunomodulatory pathway during the initiation of regeneration.

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“…Smad2 is activated when mesenchymal cells are migrating and proliferating to give rise to the regenerative structure known as “blastema”. We also demonstrated that the activity of Smad3 is not essential for the regeneration process to occur and we showed that overexpression of the protein leads to apoptosis (Denis et al., ). In addition, the immune response is weak following amputation which is reminiscent of what is observed in the Smad3 KO mouse (Mescher & Neff, ).…”

Section: Tgf‐β Target In Ecmmentioning

confidence: 81%

“…In the Axolotl regeneration process and skin wound healing MMPs are also observed (Ashcroft et al., ; Denis et al., ; Seifert et al., ; Yang & Bryant, ; Yang, Gardiner, Carlson, Nugas, & Bryant, ). Some of these enzyme are regulated by tgf‐ β (namely MMP2 and MMP9) (Denis et al., ), and they are essential for this process because inhibition of MMP activity leads to a loss of regenerative capacity (Vinarsky, Atkinson, Stevenson, Keating, & Odelberg, ). These observations point out that regulation of collagens and enzymes responsible for their remodeling is coregulated.…”

Section: Tgf‐β Target In Ecmmentioning

confidence: 99%

Tissue regeneration in dentistry: Can salamanders provide insight?

2017

Self Cite

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The ability to regenerate damaged tissues would be of tremendous benefit for medicine and dentistry. Unfortunately, humans are unable to regenerate tissues such as teeth and fingers or to repair injured spinal cord. With an aging population, health problems are more prominent and dentistry is no exception as loss of bone tissue in the orofacial sphere from periodontal disease is on the rise. Humans can repair oral soft tissues exceptionally well; however, hard tissues, such as bone and teeth, are devoid of the ability to repair well or at all. Fortunately, Mother Nature has solved nearly every problem that we would like to solve for our own benefit and tissue regeneration is no exception. By studying animals that can regenerate, like Axolotls (Mexican salamander), we hope to find ways to stimulate regeneration in humans. We will discuss the role of the transforming growth factor beta cytokines as they are central to wound healing in humans and regeneration in Axolotls. We will also compare wound healing in humans (skin and oral mucosa) to Axolotl skin wound healing and limb regeneration. Finally, we will address the problem of bone regeneration and present results in salamanders which indicate that in order to regenerate bone you need to recruit non‐bone cells. Fundamental research, such as the work being performed in animals that can regenerate, offers insight to help understand why some treatments are successful while others fail when it comes to specific tissues such as bones.

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Activation of Smad2 but not Smad3 is required to mediate TGF-β signaling during axolotl limb regeneration

Cited by 35 publications

References 82 publications

TGF‐β1 activates RSC96 Schwann cells migration and invasion through MMP‐2 and MMP‐9 activities

TGF‐β1 activates RSC96 Schwann cells migration and invasion through MMP‐2 and MMP‐9 activities

Blastemal progenitors modulate immune signaling during early limb regeneration

Tissue regeneration in dentistry: Can salamanders provide insight?

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