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In JoVE (1)
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Articles by John D. Chan in JoVE
JoVE General
भेषज और कार्यात्मक जेनेटिक Assays Planarian की पुनर्जनन में हेरफेर करने के लिए बिही Dugesia
Department of Pharmacology and The Stem Cell Institute, University of Minnesota Medical School
एक जीवित जानवर के भीतर स्टेम सेल भेदभाव के अध्ययन के लिए एक आकर्षक मॉडल planarian flatworm है. पुनर्जनन सरल विच्छेदन प्रयोगों है कि आसानी से एक बुनियादी प्रयोगशाला में प्रदर्शन कर रहे हैं के द्वारा अध्ययन किया है और (औषधीय और आनुवंशिक उत्तरदायी हैं
Other articles by John D. Chan on PubMed
A Novel Biological Activity of Praziquantel Requiring Voltage-operated Ca2+ Channel Beta Subunits: Subversion of Flatworm Regenerative Polarity
Approximately 200 million people worldwide harbour parasitic flatworm infections that cause schistosomiasis. A single drug-praziquantel (PZQ)-has served as the mainstay pharmacotherapy for schistosome infections since the 1980s. However, the relevant in vivo target(s) of praziquantel remain undefined.
Opposing Roles of Voltage-gated Ca2+ Channels in Neuronal Control of Regenerative Patterning
There is intense interest in developing methods to regulate proliferation and differentiation of stem cells into neuronal fates for the purposes of regenerative medicine. One way to do this is through in vivo pharmacological engineering using small molecules. However, a key challenge is identification of relevant signaling pathways and therein druggable targets to manipulate stem cell behavior efficiently in vivo. Here, we use the planarian flatworm as a simple chemical-genetic screening model for nervous system regeneration to show that the isoquinoline drug praziquantel (PZQ) acts as a small molecule neurogenic to produce two-headed animals with integrated CNSs following regeneration. Characterization of the entire family of planarian voltage-operated Ca(2+) channel α subunits (Ca(v)α), followed by in vivo RNAi of specific Ca(v) subunits, revealed that PZQ subverted regeneration by activation of a specific voltage-gated Ca(2+) channel isoform (Ca(v)1A). PZQ-evoked Ca(2+) entry via Ca(v)1A served to inhibit neuronally derived Hedgehog signals, as evidenced by data showing that RNAi of Ca(v)1A prevented PZQ-evoked bipolarity, Ca(2+) entry, and decreases in wnt1 and wnt11-5 levels. Surprisingly, the action of PZQ was opposed by Ca(2+) influx through a closely related neuronal Ca(v) isoform (Ca(v)1B), establishing a novel interplay between specific Ca(v)1 channel isoforms, Ca(2+) entry, and neuronal Hedgehog signaling. These data map PZQ efficacy to specific neuronal Ca(v) complexes in vivo and underscore that both activators (Ca(v)1A) and inhibitors (Ca(v)1B) of Ca(2+) influx can act as small molecule neurogenics in vivo on account of the unique coupling of Ca(2+) channels to neuronally derived polarity cues.
