scholarly journals Introducing dorsoventral patterning in adult regenerating lizard tails with gene-edited embryonic neural stem cells

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Thomas P. Lozito ◽  
Ricardo Londono ◽  
Aaron X. Sun ◽  
Megan L. Hudnall
Keyword(s):  
Stem Cells ◽  
Neural Stem Cells ◽  
Sonic Hedgehog ◽  
Hedgehog Signaling ◽  
Gene Knockout ◽  
Dorsoventral Patterning ◽  
Tail Regeneration ◽  
Neural Tubes ◽  
Cartilage Differentiation ◽  
Roof Plate

AbstractLizards regenerate amputated tails but fail to recapitulate the dorsoventral patterning achieved during embryonic development. Regenerated lizard tails form ependymal tubes (ETs) that, like embryonic tail neural tubes (NTs), induce cartilage differentiation in surrounding cells via sonic hedgehog (Shh) signaling. However, adult ETs lack characteristically roof plate-associated structures and express Shh throughout their circumferences, resulting in the formation of unpatterned cartilage tubes. Both NTs and ETs contain neural stem cells (NSCs), but only embryonic NSC populations differentiate into roof plate identities when protected from endogenous Hedgehog signaling. NSCs were isolated from parthenogenetic lizard embryos, rendered unresponsive to Hedgehog signaling via CRISPR/Cas9 gene knockout of smoothened (Smo), and implanted back into clonally-identical adults to regulate tail regeneration. Here we report that Smo knockout embryonic NSCs oppose cartilage formation when engrafted to adult ETs, representing an important milestone in the creation of regenerated lizard tails with dorsoventrally patterned skeletal tissues.

scholarly journals Perfecting the Imperfect: Introducing dorsoventral patterning into adult regenerating lizard tails with gene-edited embryonic neural stem cells.

2021 ◽  
Author(s):  
Thomas Lozito ◽  
Ricardo Londono ◽  
Aaron Sun ◽  
Megan Hudnall
Keyword(s):  
Stem Cells ◽  
Neural Stem Cells ◽  
Hedgehog Signaling ◽  
Regenerative Process ◽  
Dorsoventral Patterning ◽  
Tail Regeneration ◽  
Neural Tubes ◽  
Roof Plate ◽  
Lepidodactylus Lugubris

Abstract Lizards are able to regrow amputated tails, but the lizard tail regenerative process fails to recapitulate the dorsoventral patterning achieved during embryonic tail development. Regenerated lizard tails form ependymal tubes (ETs) that, like embryonic tail neural tubes (NTs), induce cartilage differentiation in surrounding cells via sonic hedgehog (Shh) signaling. Embryonic NTs are, themselves, dorsoventrally patterned, with Pax7+ Shh- dorsal roof plate domains that restrict cartilage skeletal formation induced by Pax7- Shh+ floor domains to ventral tail regions. However, adult regenerated tail ETs lack characteristically roof plate-associated structures and express Shh throughout their circumferences, resulting in the formation of unpatterned cartilage tube skeletons. Both NTs and ETs contain populations of neural stem cells (NSCs), but only embryonic NSC populations are able to differentiate into roof plate identities and neurons. Embryonic NSCs transplanted into regenerated tail ETs retain the capacity to form roof domains but are ultimately ventralized by the unchecked hedgehog signaling of regenerated lizard tail environments. We hypothesized that only the simultaneous repression of hedgehog signaling and enhancement of NCS roof plate differentiation capacity would induce patterning in lizard ETs and, hence, regenerated cartilage. This was tested through the use of a novel genetic engineering process in which NSCs are isolated from embryos of the parthenogenetic lizard Lepidodactylus lugubris, gene-edited in vivo, and implanted back into clonally-identical adults to regulate tail regeneration. Embryonic lizard NSC lines unresponsive to hedgehog stimulation were generated through the use of CRISPR/Cas9 technologies to knockout (KO) the signaling regulator smoothened (Smo). Exogenous Smo KO NSCs were injected into adult tail spinal cords, where they engrafted to endogenous ependymal cell populations and contributed to dorsal domains in regenerated tail ETs. Embryonic Smo KO NSCs maintained roof plate identities in vivo, and lizards treated with edited NSCs regrew tails that lacked cartilage in dorsal regions. These studies represent an important milestone in the creation of the first regenerated lizard tails with dorsoventrally patterned ETs and skeletal tissues.

scholarly journals Sonic Hedgehog and Triiodothyronine Pathway Interact in Mouse Embryonic Neural Stem Cells

2020 ◽  
Vol 21 (10) ◽  
pp. 3672
Author(s):  
Pavel Ostasov ◽  
Jan Tuma ◽  
Pavel Pitule ◽  
Jiri Moravec ◽  
Zbynek Houdek ◽  
...  
Keyword(s):  
Stem Cells ◽  
Neural Stem Cells ◽  
Sonic Hedgehog ◽  
Shh Pathway ◽  
Proliferation Activity ◽  
The Central Nervous System ◽  
Beta Gene ◽  
Potential Tool ◽  
Receptor Beta ◽  
Transplantation Therapy

Neural stem cells are fundamental to development of the central nervous system (CNS)—as well as its plasticity and regeneration—and represent a potential tool for neuro transplantation therapy and research. This study is focused on examination of the proliferation dynamic and fate of embryonic neural stem cells (eNSCs) under differentiating conditions. In this work, we analyzed eNSCs differentiating alone and in the presence of sonic hedgehog (SHH) or triiodothyronine (T3) which play an important role in the development of the CNS. We found that inhibition of the SHH pathway and activation of the T3 pathway increased cellular health and survival of differentiating eNSCs. In addition, T3 was able to increase the expression of the gene for the receptor smoothened (Smo), which is part of the SHH signaling cascade, while SHH increased the expression of the T3 receptor beta gene (Thrb). This might be the reason why the combination of SHH and T3 increased the expression of the thyroxine 5-deiodinase type III gene (Dio3), which inhibits T3 activity, which in turn affects cellular health and proliferation activity of eNSCs.

scholarly journals Sonic Hedgehog Signaling Mediates Resveratrol to Increase Proliferation of Neural Stem Cells After Oxygen-Glucose Deprivation/Reoxygenation Injury in Vitro

2015 ◽  
Vol 35 (5) ◽  
pp. 2019-2032 ◽  
Author(s):  
Wei Cheng ◽  
Pingping Yu ◽  
Li Wang ◽  
Changbo Shen ◽  
Xiaosong Song ◽  
...  
Keyword(s):  
Stem Cells ◽  
Neural Stem Cells ◽  
Sonic Hedgehog ◽  
Glucose Deprivation ◽  
Adult Brain ◽  
Immunocytochemical Staining ◽  
Oxygen Glucose Deprivation ◽  
Shh Signaling ◽  
Gli 1

Background/Aims: There is interest in drugs and rehabilitation methods to enhance neurogenesis and improve neurological function after brain injury or degeneration. Resveratrol may enhance hippocampal neurogenesis and improve hippocampal atrophy in chronic fatigue mice and prenatally stressed rats. However, its effect and mechanism of neurogenesis after stroke is less well understood. Sonic hedgehog (Shh) signaling is crucial for neurogenesis in the embryonic and adult brain, but relatively little is known about the role of Shh signaling in resveratrol-enhanced neurogenesis after stroke. Methods: Neural stem cells (NSCs) before oxygen-glucose deprivation/reoxygenation (OGD/R) in vitro were pretreated with resveratrol with or without cyclopamine. Survival and proliferation of NSCs was assessed by the CCK8 assay and BrdU immunocytochemical staining. The expressions and activity of signaling proteins and mRNAs were detected by immunocytochemistry, Western blotting, and RT-PCR analysis. Results: Resveratrol significantly increased NSCs survival and proliferation in a concentration-dependent manner after OGD/R injury in vitro. At the same time, the expression of Patched-1, Smoothened (Smo), and Gli-1 proteins and mRNAs was upregulated, and Gli-1 entered the nucleus, which was inhibited by cyclopamine, a Smo inhibitor. Conclusion: Shh signaling mediates resveratrol to increase NSCs proliferation after OGD/R injury in vitro.

Cancer Stem Cells Equipped with Powerful Hedgehog Signaling and Better Epigenetic Memory: Avenues to Look for Cancer Therapeutics

2019 ◽  
Vol 19 (11) ◽  
pp. 877-884 ◽  
Author(s):  
Ishita Tandon ◽  
Asawari Waghmode ◽  
Nilesh Kumar Sharma
Keyword(s):  
Stem Cells ◽  
Cancer Stem Cells ◽  
Sonic Hedgehog ◽  
Hedgehog Signaling ◽  
Cancer Therapeutics ◽  
Complex Nature ◽  
Epigenetic Memory ◽  
Therapeutic Approaches ◽  
Shh Signaling ◽  
Memory Power

Complex nature of the tumor is depicted at the cellular landscape by showing heterogeneity in the presence of cancer cells, cancer-associated stromal cells, mesenchymal stem cells and cancer stem cells (CSCs). One of the plausible views in cancer formation is suggested as the theory of cancer CSCs that is known as a source of initiation of tumorigenesis. In essence, these powerful CSCs are equipped with high Sonic Hedgehog (SHH) signaling and epigenetic memory power that support various tumor hallmarks. Truly, nature justifies its intent by limiting these stem cells with a potential to turn into CSCs and in turn suppressing the high risk of humans and other organisms. In short, this mini-review addresses the contribution of SHH signaling to allow reprogramming of epigenetic memory within CSCs that support tumor hallmarks. Besides, this paper explores therapeutic approaches to mitigate SHH signaling that may lead to a blockade of the pro-tumor potential of CSCs.

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