Project description:The neuropeptides CGRP (calcitonin gene-related peptide) and PACAP (pituitary adenylate cyclase-activating polypeptide) have emerged as mediators of migraine, yet the potential overlap of their mechanisms remains unknown. Infusion of PACAP, like CGRP, can cause migraine in people, and both peptides share similar vasodilatory and nociceptive functions. In this study, we have used light aversion in mice as a surrogate for migraine-like photophobia to compare CGRP and PACAP and ask whether CGRP or PACAP actions were dependent on each other. Similar to CGRP, PACAP induced light aversion in outbred CD-1 mice. The light aversion was accompanied by increased resting in the dark, but not anxiety in a light-independent open field assay. Unexpectedly, about one-third of the CD-1 mice did not respond to PACAP, which was not seen with CGRP. The responder and nonresponder phenotypes were stable, inheritable, and not sex linked, although there was a trend for greater responses among male mice. RNA-sequencing analysis of trigeminal ganglia yielded hierarchical clustering of responder and nonresponder mice and revealed a number of candidate genes, including greater expression of the Trpc5 and Kcnk12 ion channels and glycoprotein hormones and receptors in a subset of male responder mice. Importantly, an anti-PACAP monoclonal antibody could block PACAP-induced light aversion but not CGRP-induced light aversion. Conversely, an anti-CGRP antibody could not block PACAP-induced light aversion. Thus, we propose that CGRP and PACAP act by independent convergent pathways that cause a migraine-like symptom in mice.SIGNIFICANCE STATEMENT The relationship between the neuropeptides CGRP (calcitonin gene-related peptide) and PACAP (pituitary adenylate cyclase-activating polypeptide) in migraine is relevant given that both peptides can induce migraine in people, yet to date only drugs that target CGRP are available. Using an outbred strain of mice, we were able to show that most, but not all, mice respond to PACAP in a preclinical photophobia assay. Our finding that CGRP and PACAP monoclonal antibodies do not cross-inhibit the other peptide indicates that CGRP and PACAP actions are independent and suggests that PACAP-targeted drugs may be effective in patients who do not respond to CGRP-based therapeutics.

Project description:We investigated the effects of PACAP treatment, and endogenous PACAP deficiency, on infarct volume, neurological function, and the cerebrocortical transcriptional response in a mouse model of stroke, middle cerebral artery occlusion (MCAO). PACAP-38 administered i.v. or i.c.v. one hour after MCAO significantly reduced infarct volume, and ameliorated functional motor deficits measured 24 hours later in wild-type mice. Infarct volumes and neurological deficits (walking faults) were both greater in PACAP-deficient than in wild-type mice, but treatment with PACAP reduced lesion volume and neurological deficits in PACAP-deficient mice to the same level of improvement as in wild-type mice. A 35,546-clone mouse cDNA microarray was used to investigate cortical transcriptional changes associated with cerebral ischemia in wild-type and PACAP-deficient mice, and with PACAP treatment after MCAO in wild-type mice. 229 known (named) transcripts were increased (228) or decreased (1) in abundance at least 50% following cerebral ischemia in wild-type mice. 49 transcripts were significantly up-regulated only at one hour post-MCAO (acute response transcripts), 142 were up-regulated only at 24 hours post-MCAO (delayed response transcripts) and 37 transcripts were up-regulated at both times (sustained response transcripts). More than 50% of these are transcripts not previously reported to be associated with brain ischemia responses. Many of the acutely regulated neurotrauma-associated transcripts, but a larger percentage of the delayed ones, require endogenous PACAP for up-regulation by ischemia, suggesting a more prominent role for PACAP in later response to injury than in the initial response, and consistent with a neuroprotective role for PACAP in late response to injury and neuroprotective efficacy when given post-MCAO. Putative injury effector transcripts regulated by PACAP include ãÑ-actin, midline 2, and metallothionein 1. Potential neuroprotective transcripts include several demonstrated to be PACAP-regulated in other contexts. Prominent among these were transcripts encoding the PACAP-regulated gene Ier3, and the neuropeptides enkephalin, substance P (tachykinin 1), and neurotensin. Keywords: transcript identification design

Project description:We investigated the effects of PACAP treatment, and endogenous PACAP deficiency, on infarct volume, neurological function, and the cerebrocortical transcriptional response in a mouse model of stroke, middle cerebral artery occlusion (MCAO). PACAP-38 administered i.v. or i.c.v. one hour after MCAO significantly reduced infarct volume, and ameliorated functional motor deficits measured 24 hours later in wild-type mice. Infarct volumes and neurological deficits (walking faults) were both greater in PACAP-deficient than in wild-type mice, but treatment with PACAP reduced lesion volume and neurological deficits in PACAP-deficient mice to the same level of improvement as in wild-type mice. A 35,546-clone mouse cDNA microarray was used to investigate cortical transcriptional changes associated with cerebral ischemia in wild-type and PACAP-deficient mice, and with PACAP treatment after MCAO in wild-type mice. 229 known (named) transcripts were increased (228) or decreased (1) in abundance at least 50% following cerebral ischemia in wild-type mice. 49 transcripts were significantly up-regulated only at one hour post-MCAO (acute response transcripts), 142 were up-regulated only at 24 hours post-MCAO (delayed response transcripts) and 37 transcripts were up-regulated at both times (sustained response transcripts). More than 50% of these are transcripts not previously reported to be associated with brain ischemia responses. Many of the acutely regulated neurotrauma-associated transcripts, but a larger percentage of the delayed ones, require endogenous PACAP for up-regulation by ischemia, suggesting a more prominent role for PACAP in later response to injury than in the initial response, and consistent with a neuroprotective role for PACAP in late response to injury and neuroprotective efficacy when given post-MCAO. Putative injury effector transcripts regulated by PACAP include Ã£Ã-actin, midline 2, and metallothionein 1. Potential neuroprotective transcripts include several demonstrated to be PACAP-regulated in other contexts. Prominent among these were transcripts encoding the PACAP-regulated gene Ier3, and the neuropeptides enkephalin, substance P (tachykinin 1), and neurotensin. In the hybridization method employed, equal amounts (2-5Ã£Ãg/15.5 Ã£Ãl) of total RNA obtained from brain tissue of different experimental groups were separately labeled with two different fluorescent dyes (Cy3 or Cy5) and applied on the same NIMH Mouse 36K cDNA microarray chip containing 13217 distinct Entrez gene IDs (formerly known as LocusLink) and 15888 distinct unigene IDs, the remainders are incompletely annotated IMAGE clones. Probe preparation and hybridization were performed as follows. The total RNA (15-50 Ã£Ãg in 15.5 Ã£Ãl) was incubated with amine-modified random primer (2 Ã£Ãg/Ã£Ãl, 2 Ã£Ãl) and RNase inhibitor (5 units/Ã£Ãl, 1 Ã£Ãl) at 70 Ã¤aC for 10 min. Primer-RNA solution was then incubated at 42 Ã¤aC for 2 hr with the reverse transcriptase mix containing 5X first-strand buffer, 50X aa-dUTP/dNTPs (25 mM dATP, 25 mM dGTP, 25 mM dCTP, 15 mM dTTP and 10 mM aminoallyl dUTP), 0.1 M DDT, and Superscript II reverse transcriptase. The cDNA were labeled with NHS-ester Cy3 or Cy5 dye in the presence of 1 M sodium bicarbonate. Array slides placed in a hybridization chamber (Corning, Corning, NY) were incubated at 42 Ã¤aC for 16-24 hr, and successively washed with 0.5X SSC, 0.01% SDS, and 0.06X SSC at room temperature for 10 min each. Arrays were scanned with a GenePix 4000A scanner (Axon, Foster City, CA), and the resulting images were analyzed using IPlab (Fairfax, VA) and a FileMaker Pro 5 (Santa Clara, CA) relational database designed by Zedong Chen, NHGRI. Following background subtraction and normalization, a calculated ratio of Cy3 to Cy5 signal intensities was used to define the relative increase or decrease of a particular transcript. Ratios were calculated only from those spots with a combined ratio quality above 0.3.

			Action	DRS
	SRR14568741_1.fastq.gz	Fastqsanger.gz
	SRR14568741_2.fastq.gz	Fastqsanger.gz
	SRR14568742_1.fastq.gz	Fastqsanger.gz
	SRR14568742_2.fastq.gz	Fastqsanger.gz
	SRR14568743_1.fastq.gz	Fastqsanger.gz

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PACAP Induces Light Aversion in Mice by an Inheritable Mechanism Independent of CGRP

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