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Mmp1 processing of the PDF neuropeptide regulates circadian structural plasticity of pacemaker neurons.

Depetris-Chauvin A, Fernández-Gamba A, Gorostiza EA, Herrero A, Castaño EM, Ceriani MF - PLoS Genet. (2014)

Bottom Line: Interestingly, PDF immunoreactivity at the dorsal terminals changes across the day as synaptic contacts do as a result of a remarkable remodeling of sLNv projections.However, only Mmp1 affects PDF immunoreactivity at the dorsal terminals and exerts a clear effect on overt behavior.These data demonstrate that Mmp1 modulates PDF processing, which leads to daily structural remodeling and circadian behavior.

View Article: PubMed Central - PubMed

Affiliation: Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas-Buenos Aires (IIB-BA, CONICET), Buenos Aires, Argentina.

ABSTRACT
In the Drosophila brain, the neuropeptide PIGMENT DISPERSING FACTOR (PDF) is expressed in the small and large Lateral ventral neurons (LNvs) and regulates circadian locomotor behavior. Interestingly, PDF immunoreactivity at the dorsal terminals changes across the day as synaptic contacts do as a result of a remarkable remodeling of sLNv projections. Despite the relevance of this phenomenon to circuit plasticity and behavior, the underlying mechanisms remain poorly understood. In this work we provide evidence that PDF along with matrix metalloproteinases (Mmp1 and 2) are key in the control of circadian structural remodeling. Adult-specific downregulation of PDF levels per se hampers circadian axonal remodeling, as it does altering Mmp1 or Mmp2 levels within PDF neurons post-developmentally. However, only Mmp1 affects PDF immunoreactivity at the dorsal terminals and exerts a clear effect on overt behavior. In vitro analysis demonstrated that PDF is hydrolyzed by Mmp1, thereby suggesting that Mmp1 could directly terminate its biological activity. These data demonstrate that Mmp1 modulates PDF processing, which leads to daily structural remodeling and circadian behavior.

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PDF defines the axonal remodeling of its own neurons.A. Quantitation of total axonal crosses from UAS-PDF rescue experiments. Overexpression of PDF rescues the structural plasticity defects caused by Mmp1 overexpression. “+” in the x axis refers to a single copy of CD8GFP; pdf-GS. Data represents the average (± standard error of the mean) between 3–5 independent experiments and a minimum of 21 flies were analyzed per Genotype/CT. B. PDF downregulation prevents circadian axonal remodeling of sLNv terminals and reduces daytime complexity to nighttime levels. “+” in the x axis refers to a single copy of CD8GFP, Dcr2; pdf-GS. Data represents the average (± standard error of the mean) between 3 independent experiments and a minimum of 25 flies were analyzed per Genotype/CT. In both experiments different letters indicate statistical differences with a p<0.05 (Two-way ANOVA with a Duncan post-hoc test) and all the experimental groups include RU to induce expression.
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pgen-1004700-g004: PDF defines the axonal remodeling of its own neurons.A. Quantitation of total axonal crosses from UAS-PDF rescue experiments. Overexpression of PDF rescues the structural plasticity defects caused by Mmp1 overexpression. “+” in the x axis refers to a single copy of CD8GFP; pdf-GS. Data represents the average (± standard error of the mean) between 3–5 independent experiments and a minimum of 21 flies were analyzed per Genotype/CT. B. PDF downregulation prevents circadian axonal remodeling of sLNv terminals and reduces daytime complexity to nighttime levels. “+” in the x axis refers to a single copy of CD8GFP, Dcr2; pdf-GS. Data represents the average (± standard error of the mean) between 3 independent experiments and a minimum of 25 flies were analyzed per Genotype/CT. In both experiments different letters indicate statistical differences with a p<0.05 (Two-way ANOVA with a Duncan post-hoc test) and all the experimental groups include RU to induce expression.

Mentions: Recently, we have demonstrated that the PDF neuropeptide operates during development to determine the fine structure of the dorsal axonal projections of sLNv neurons [33]. As we demonstrated here, Mmp1 affects the circadian remodeling of PDF projections in the adult, concomitantly altering the levels of the neuropeptide. We reasoned that if PDF was responsible for the daily axonal remodeling of sLNvs, rescuing PDF levels in the context of Mmp1 overexpression should reestablish circadian structural plasticity. Indeed, PDF overexpression in the context of Mmp1 overexpression restored circadian structural plasticity of PDF neurons to wild type levels (Figure 4A). To directly test a role of the neuropeptide on the plasticity of sLNv neurons, we expressed a specific RNAi to downregulate PDF levels in an adult-specific fashion and analyzed its effect on circadian axonal remodeling. PDF knockdown caused a severe abrogation of the daily remodeling of axonal terminals that rendered the structure in a configuration reminiscent of the one observed in animals overexpressing Mmp1 (Figure 4B).


Mmp1 processing of the PDF neuropeptide regulates circadian structural plasticity of pacemaker neurons.

Depetris-Chauvin A, Fernández-Gamba A, Gorostiza EA, Herrero A, Castaño EM, Ceriani MF - PLoS Genet. (2014)

PDF defines the axonal remodeling of its own neurons.A. Quantitation of total axonal crosses from UAS-PDF rescue experiments. Overexpression of PDF rescues the structural plasticity defects caused by Mmp1 overexpression. “+” in the x axis refers to a single copy of CD8GFP; pdf-GS. Data represents the average (± standard error of the mean) between 3–5 independent experiments and a minimum of 21 flies were analyzed per Genotype/CT. B. PDF downregulation prevents circadian axonal remodeling of sLNv terminals and reduces daytime complexity to nighttime levels. “+” in the x axis refers to a single copy of CD8GFP, Dcr2; pdf-GS. Data represents the average (± standard error of the mean) between 3 independent experiments and a minimum of 25 flies were analyzed per Genotype/CT. In both experiments different letters indicate statistical differences with a p<0.05 (Two-way ANOVA with a Duncan post-hoc test) and all the experimental groups include RU to induce expression.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4214601&req=5

pgen-1004700-g004: PDF defines the axonal remodeling of its own neurons.A. Quantitation of total axonal crosses from UAS-PDF rescue experiments. Overexpression of PDF rescues the structural plasticity defects caused by Mmp1 overexpression. “+” in the x axis refers to a single copy of CD8GFP; pdf-GS. Data represents the average (± standard error of the mean) between 3–5 independent experiments and a minimum of 21 flies were analyzed per Genotype/CT. B. PDF downregulation prevents circadian axonal remodeling of sLNv terminals and reduces daytime complexity to nighttime levels. “+” in the x axis refers to a single copy of CD8GFP, Dcr2; pdf-GS. Data represents the average (± standard error of the mean) between 3 independent experiments and a minimum of 25 flies were analyzed per Genotype/CT. In both experiments different letters indicate statistical differences with a p<0.05 (Two-way ANOVA with a Duncan post-hoc test) and all the experimental groups include RU to induce expression.
Mentions: Recently, we have demonstrated that the PDF neuropeptide operates during development to determine the fine structure of the dorsal axonal projections of sLNv neurons [33]. As we demonstrated here, Mmp1 affects the circadian remodeling of PDF projections in the adult, concomitantly altering the levels of the neuropeptide. We reasoned that if PDF was responsible for the daily axonal remodeling of sLNvs, rescuing PDF levels in the context of Mmp1 overexpression should reestablish circadian structural plasticity. Indeed, PDF overexpression in the context of Mmp1 overexpression restored circadian structural plasticity of PDF neurons to wild type levels (Figure 4A). To directly test a role of the neuropeptide on the plasticity of sLNv neurons, we expressed a specific RNAi to downregulate PDF levels in an adult-specific fashion and analyzed its effect on circadian axonal remodeling. PDF knockdown caused a severe abrogation of the daily remodeling of axonal terminals that rendered the structure in a configuration reminiscent of the one observed in animals overexpressing Mmp1 (Figure 4B).

Bottom Line: Interestingly, PDF immunoreactivity at the dorsal terminals changes across the day as synaptic contacts do as a result of a remarkable remodeling of sLNv projections.However, only Mmp1 affects PDF immunoreactivity at the dorsal terminals and exerts a clear effect on overt behavior.These data demonstrate that Mmp1 modulates PDF processing, which leads to daily structural remodeling and circadian behavior.

View Article: PubMed Central - PubMed

Affiliation: Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas-Buenos Aires (IIB-BA, CONICET), Buenos Aires, Argentina.

ABSTRACT
In the Drosophila brain, the neuropeptide PIGMENT DISPERSING FACTOR (PDF) is expressed in the small and large Lateral ventral neurons (LNvs) and regulates circadian locomotor behavior. Interestingly, PDF immunoreactivity at the dorsal terminals changes across the day as synaptic contacts do as a result of a remarkable remodeling of sLNv projections. Despite the relevance of this phenomenon to circuit plasticity and behavior, the underlying mechanisms remain poorly understood. In this work we provide evidence that PDF along with matrix metalloproteinases (Mmp1 and 2) are key in the control of circadian structural remodeling. Adult-specific downregulation of PDF levels per se hampers circadian axonal remodeling, as it does altering Mmp1 or Mmp2 levels within PDF neurons post-developmentally. However, only Mmp1 affects PDF immunoreactivity at the dorsal terminals and exerts a clear effect on overt behavior. In vitro analysis demonstrated that PDF is hydrolyzed by Mmp1, thereby suggesting that Mmp1 could directly terminate its biological activity. These data demonstrate that Mmp1 modulates PDF processing, which leads to daily structural remodeling and circadian behavior.

Show MeSH