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Proliferative regeneration of zebrafish lateral line hair cells after different ototoxic insults.

Mackenzie SM, Raible DW - PLoS ONE (2012)

Bottom Line: Certain treatments, including cisplatin and higher concentrations of dissolved copper, significantly delayed regeneration by one or more days.However, cisplatin did not block all regeneration as observed previously in the chick basilar papilla.The particular ototoxin did not appear to affect the mechanism of regeneration, as we observed evidence of recent proliferation in the majority of new hair cells in all cases.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Structure, University of Washington, Seattle, Washington, United States of America.

ABSTRACT
Sensory hair cells in the zebrafish lateral line regenerate rapidly and completely after damage. Previous studies have used a variety of ototoxins to kill lateral line hair cells to study different phenomena including mechanisms of hair cell death and regeneration. We sought to directly compare these ototoxins to determine if they differentially affected the rate and amount of hair cell replacement. In addition, previous studies have found evidence of proliferative hair cell regeneration in zebrafish, but both proliferation and non-mitotic direct transdifferentiation have been observed during hair cell regeneration in the sensory epithelia of birds and amphibians. We sought to test whether a similar combination of regenerative mechanisms exist in the fish. We analyzed the time course of regeneration after treatment with different ototoxic compounds and also labeled dividing hair cell progenitors. Certain treatments, including cisplatin and higher concentrations of dissolved copper, significantly delayed regeneration by one or more days. However, cisplatin did not block all regeneration as observed previously in the chick basilar papilla. The particular ototoxin did not appear to affect the mechanism of regeneration, as we observed evidence of recent proliferation in the majority of new hair cells in all cases. Inhibiting proliferation with flubendazole blocked the production of new hair cells and prevented the accumulation of additional precursors, indicating that proliferation has a dominant role during regeneration of lateral line hair cells.

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Copper may impair hair cell regeneration.(A, B) Wild type larvae were treated at 5 dpf with serial dilutions of neomycin or copper for 30 min. Hair cell regeneration was scored using FM 1-43FX and normalized to controls. Regeneration was incomplete in groups treated with 3 or 10 μM copper, but other groups recovered fully. N = 7 fish per group. (C) Individual counts of hair cells labeled with antibodies against parvalbumin confirmed incomplete regeneration in larvae treated for 1 h with copper. N = 8 fish per group. Error bars are +/− SD.
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pone-0047257-g002: Copper may impair hair cell regeneration.(A, B) Wild type larvae were treated at 5 dpf with serial dilutions of neomycin or copper for 30 min. Hair cell regeneration was scored using FM 1-43FX and normalized to controls. Regeneration was incomplete in groups treated with 3 or 10 μM copper, but other groups recovered fully. N = 7 fish per group. (C) Individual counts of hair cells labeled with antibodies against parvalbumin confirmed incomplete regeneration in larvae treated for 1 h with copper. N = 8 fish per group. Error bars are +/− SD.

Mentions: We next compared hair cell regeneration after treatment with copper or neomycin on larvae at 5 dpf, when neuromast development is largely complete. As reported previously [15], [39], we observed full regeneration after treatment with varying concentrations of neomycin (Figure 2A,C). In contrast, not all larvae treated with copper experienced full regeneration. Larvae treated with 1 μM copper for 30 min fully recovered, but larvae treated with 10 μM copper for 30 min exhibited incomplete regeneration (Figure 2B,C), as did larvae treated with either concentration for 2 h (data not shown). These results are consistent with previous studies describing the effects of copper on hair cell regeneration [17] and damage to hair cell progenitors [40] in younger, 3 dpf embryos.


Proliferative regeneration of zebrafish lateral line hair cells after different ototoxic insults.

Mackenzie SM, Raible DW - PLoS ONE (2012)

Copper may impair hair cell regeneration.(A, B) Wild type larvae were treated at 5 dpf with serial dilutions of neomycin or copper for 30 min. Hair cell regeneration was scored using FM 1-43FX and normalized to controls. Regeneration was incomplete in groups treated with 3 or 10 μM copper, but other groups recovered fully. N = 7 fish per group. (C) Individual counts of hair cells labeled with antibodies against parvalbumin confirmed incomplete regeneration in larvae treated for 1 h with copper. N = 8 fish per group. Error bars are +/− SD.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3475690&req=5

pone-0047257-g002: Copper may impair hair cell regeneration.(A, B) Wild type larvae were treated at 5 dpf with serial dilutions of neomycin or copper for 30 min. Hair cell regeneration was scored using FM 1-43FX and normalized to controls. Regeneration was incomplete in groups treated with 3 or 10 μM copper, but other groups recovered fully. N = 7 fish per group. (C) Individual counts of hair cells labeled with antibodies against parvalbumin confirmed incomplete regeneration in larvae treated for 1 h with copper. N = 8 fish per group. Error bars are +/− SD.
Mentions: We next compared hair cell regeneration after treatment with copper or neomycin on larvae at 5 dpf, when neuromast development is largely complete. As reported previously [15], [39], we observed full regeneration after treatment with varying concentrations of neomycin (Figure 2A,C). In contrast, not all larvae treated with copper experienced full regeneration. Larvae treated with 1 μM copper for 30 min fully recovered, but larvae treated with 10 μM copper for 30 min exhibited incomplete regeneration (Figure 2B,C), as did larvae treated with either concentration for 2 h (data not shown). These results are consistent with previous studies describing the effects of copper on hair cell regeneration [17] and damage to hair cell progenitors [40] in younger, 3 dpf embryos.

Bottom Line: Certain treatments, including cisplatin and higher concentrations of dissolved copper, significantly delayed regeneration by one or more days.However, cisplatin did not block all regeneration as observed previously in the chick basilar papilla.The particular ototoxin did not appear to affect the mechanism of regeneration, as we observed evidence of recent proliferation in the majority of new hair cells in all cases.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Structure, University of Washington, Seattle, Washington, United States of America.

ABSTRACT
Sensory hair cells in the zebrafish lateral line regenerate rapidly and completely after damage. Previous studies have used a variety of ototoxins to kill lateral line hair cells to study different phenomena including mechanisms of hair cell death and regeneration. We sought to directly compare these ototoxins to determine if they differentially affected the rate and amount of hair cell replacement. In addition, previous studies have found evidence of proliferative hair cell regeneration in zebrafish, but both proliferation and non-mitotic direct transdifferentiation have been observed during hair cell regeneration in the sensory epithelia of birds and amphibians. We sought to test whether a similar combination of regenerative mechanisms exist in the fish. We analyzed the time course of regeneration after treatment with different ototoxic compounds and also labeled dividing hair cell progenitors. Certain treatments, including cisplatin and higher concentrations of dissolved copper, significantly delayed regeneration by one or more days. However, cisplatin did not block all regeneration as observed previously in the chick basilar papilla. The particular ototoxin did not appear to affect the mechanism of regeneration, as we observed evidence of recent proliferation in the majority of new hair cells in all cases. Inhibiting proliferation with flubendazole blocked the production of new hair cells and prevented the accumulation of additional precursors, indicating that proliferation has a dominant role during regeneration of lateral line hair cells.

Show MeSH
Related in: MedlinePlus