Nanoscale Surveillance of the Brain by Microglia via cAMP-Regulated Filopodia

Bernier, Louis‐Philippe; Bohlen, Christopher J.; York, Elisa M.; Choi, Hyun B.; Kamyabi, Alireza; Dissing-Olesen, Lasse; Hefendehl, Jasmin K.; Collins, Hannah Y.; Stevens, Beth; Barres, Ben A.; MacVicar, Brian A.

doi:10.1016/j.celrep.2019.05.010

Cited by 173 publications

(177 citation statements)

References 85 publications

(123 reference statements)

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“…Intriguingly, many of the RNAs that are altered related to cyclic-AMP signaling, and inhibiting cAMPmediated signaling in microglia with Gi/o coupled DREADD activation exacerbated the acute behavioral signs of withdrawal. We also observed changes in microglia process branching and termination following opioid tolerance that was rapidly reversed during withdrawal and was consistent with cAMP effects on microglia morphology 25 . Together, this data suggests that microglia are actively involved in both opioid tolerance and withdrawal in a compensatory manner.…”

Section: Opioid Abuse Has Reached Epidemic Proportions In the Unitedsupporting

confidence: 82%

“…The microglia imaged in this report do not appear to be classically activated, but rather show modest changes in morphology and process branching and termination. While we did not predict these results, they are entirely consistent with a recent report showing that microglia engage in nanoscale surveillance of the brain via cAMP regulated filopodia 25 . That report showed that decreasing intracellular cAMP results in microglial process elongation, while increasing cAMP causes process retraction.…”

Section: Striatal Microglia Morphology Is Altered By Morphine Toleransupporting

confidence: 80%

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RiboTag-Seq Reveals a Compensatory cAMP Responsive Gene Network in Striatal Microglia Induced by Morphine Withdrawal

Coffey

Lesiak

Marx

et al. 2020

Preprint

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Microglia have recently been implicated in dependence to opioids. To investigate this directly, we used RNA sequencing of ribosome associated RNAs from striatal microglia (RiboTag-Seq) after the induction of morphine tolerance and then the precipitation of withdrawal by naloxone. We detected large, inverse changes in RNA translation following opioid tolerance and withdrawal, and bioinformatics analysis revealed an intriguing upregulation of cAMP-associated genes that are involved in microglial motility, morphology, and interactions with neurons. Three-dimensional histological reconstruction of microglia revealed changes in process branching and termination following opioid tolerance that were rapidly reversed during withdrawal and were consistent with cAMP effects on microglia morphology. Direct activation of Gicoupled DREADD receptors in microglia, rather than mimicking the effects of morphine, exacerbated opioid withdrawal. Together these indicate that microglial response to cAMP signaling can mitigate the rapid manifestations of opioid withdrawal. inverse relationship between gene expression changes duringFigure 4. Differential Expression Analysis | Naloxone administration to non-morphine-dependent animals has little effect on gene expression in the a, IP samples or d, Input samples. Morphine tolerance produces roughly equal numbers of upregulated and downregulated DEGs in both the b, IP sample and e, Input sample. Naloxone administration to morphine dependent animals produces mainly upregulation of DEGs in both the c, IP and f, Input samples. Gene expression changes during withdrawal are inversely correlated to gene expression changes during morphine tolerance in both the g, IP sample and h, Input sample.Roughly half of IP DEGs were also differentially expressed in the Input samples for both i, morphine tolerance and j, withdrawal, suggesting a common mechanism of action in neurons and microglia.

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Section: Opioid Abuse Has Reached Epidemic Proportions In the Unitedsupporting

confidence: 82%

Section: Striatal Microglia Morphology Is Altered By Morphine Toleransupporting

confidence: 80%

RiboTag-Seq Reveals a Compensatory cAMP Responsive Gene Network in Striatal Microglia Induced by Morphine Withdrawal

Coffey

Lesiak

Marx

et al. 2020

Preprint

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“…This increase may reflect more trafficking to the membrane of P2Y 12 receptors in the P2Y 13 KO, better coupling of P2Y 12 to THIK‐1 in the absence of P2Y 13 , or alternatively an effect of the increase of intracellular cyclic AMP level (e.g., altering phosphorylation and potentiating P2Y 12 action) expected when the G i ‐coupled P2Y 13 is knocked out (assuming that there is constitutive activity of P2Y 13 , which is not known). This is in line with our data showing that an elevation of cAMP levels, either by applying forskolin to WT slices or perfusing cAMP intracellularly via the patch‐clamp solution, causes WT microglial cells to adopt features seen in P2Y 13 KO microglia, such as reduced surveillance and ramification (consistent with Bernier et al, ), and a larger P2Y 12 ‐activated THIK‐1 current (Figure S2b). Despite this increased sensitivity to ADP, the P2Y 13 KO cells moved their processes at a similar speed to those of the WT towards an ADP source, where they nevertheless arrived later because the KO cells are less ramified and have shorter processes, and thus they have to grow further than the WT cell processes until they reach their target.…”

Section: Discussionsupporting

confidence: 92%

P2Y₁₃ receptors regulate microglial morphology, surveillance, and resting levels of interleukin 1β release

Kyrargyri

Madry

Rifat

et al. 2019

Glia

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Microglia sense their environment using an array of membrane receptors. While P2Y12 receptors are known to play a key role in targeting directed motility of microglial processes to sites of damage where ATP/ADP is released, little is known about the role of P2Y13, which transcriptome data suggest is the second most expressed neurotransmitter receptor in microglia. We show that, in patch‐clamp recordings in acute brain slices from mice lacking P2Y13 receptors, the THIK‐1 K+ current density evoked by ADP activating P2Y12 receptors was increased by ~50%. This increase suggested that the P2Y12‐dependent chemotaxis response should be potentiated; however, the time needed for P2Y12‐mediated convergence of microglial processes onto an ADP‐filled pipette or to a laser ablation was longer in the P2Y13 KO. Anatomical analysis showed that the density of microglia was unchanged, but that they were less ramified with a shorter process length in the P2Y13 KO. Thus, chemotactic processes had to grow further and so arrived later at the target, and brain surveillance was reduced by ~30% in the knock‐out. Blocking P2Y12 receptors in brain slices from P2Y13 KO mice did not affect surveillance, demonstrating that tonic activation of these high‐affinity receptors is not needed for surveillance. Strikingly, baseline interleukin‐1β release was increased fivefold while release evoked by LPS and ATP was not affected in the P2Y13 KO, and microglia in intact P2Y13 KO brains were not detectably activated. Thus, P2Y13 receptors play a role different from that of their close relative P2Y12 in regulating microglial morphology and function.

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“…P2RY12 is a nucleotide sensing metabotropic GPCR in the P2Y family of GPCRs that has an important role in the microglial "sensome" (Hickman et al, 2013). P2RY12 regulates the microglial response to tissue damage and the adoption of the amoeboid "activated" microglial morphology (Bernier et al, 2019;Haynes et al, 2006). We found that P2ry12-CreER, unlike the commonly used Cx3cr1-CreER, specifically labeled brain microglia, but not perivascular or meningeal macrophages.…”

Section: Cx3cr1-creermentioning

confidence: 81%

New Tools for Genetically Targeting Myeloid Populations in the Central Nervous System

Gl¹,

Lizama²,

Ae³

et al. 2019

Preprint

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As the resident macrophages of the brain and spinal cord, microglia are crucial for the phagocytosis of infectious agents, apoptotic cells and synapses. Developmentally, microglia originate from the embryonic yolk sac and serve important roles in the sculpting of neonatal neural circuits. During brain injury or infection, bone-marrow derived macrophages invade neural tissue, making it difficult to distinguish between invading macrophages and resident microglia. In addition to circulation-derived monocytes, other non-microglial central nervous system (CNS) macrophage subtypes include borderzone (meningeal and perivascular) and choroid plexus macrophages. To distinguish between resident microglia and these other CNS macrophage subtypes, we generated a P2ry12-CreER mouse line. P2RY12 is a microglialspecific nucleotide sensing GPCR that is important for microglial response to tissue damage. Using immunofluorescent labeling and flow cytometry experiments, we show that P2ry12-CreER recombination is exceptionally specific to parenchymal microglia. We also perform ribosome immunoprecipitations and transcriptional profiling of P2ry12-CreER recombined cells, using a Cre-dependent Rpl22-HA mouse line. By identifying genes enriched in this dataset that are not correspondingly enriched in a broader Cx3CR1-CreER; Rpl22 dataset, we isolate a number of borderzone macrophage-specific transcripts, including the gene PF4. Using a PF4-Cre mouse line, we show that PF4 expression robustly marks borderzone macrophages. Together, we demonstrate two new methods to genetically target distinct CNS macrophage subtypes.

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Nanoscale Surveillance of the Brain by Microglia via cAMP-Regulated Filopodia

Cited by 173 publications

References 85 publications

RiboTag-Seq Reveals a Compensatory cAMP Responsive Gene Network in Striatal Microglia Induced by Morphine Withdrawal

RiboTag-Seq Reveals a Compensatory cAMP Responsive Gene Network in Striatal Microglia Induced by Morphine Withdrawal

P2Y₁₃ receptors regulate microglial morphology, surveillance, and resting levels of interleukin 1β release

New Tools for Genetically Targeting Myeloid Populations in the Central Nervous System

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Nanoscale Surveillance of the Brain by Microglia via cAMP-Regulated Filopodia

Cited by 173 publications

References 85 publications

RiboTag-Seq Reveals a Compensatory cAMP Responsive Gene Network in Striatal Microglia Induced by Morphine Withdrawal

RiboTag-Seq Reveals a Compensatory cAMP Responsive Gene Network in Striatal Microglia Induced by Morphine Withdrawal

P2Y13 receptors regulate microglial morphology, surveillance, and resting levels of interleukin 1β release

New Tools for Genetically Targeting Myeloid Populations in the Central Nervous System

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Product

Resources

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P2Y₁₃ receptors regulate microglial morphology, surveillance, and resting levels of interleukin 1β release