Comparing Gene Expression in the Parabrachial and Amygdala of Diestrus and Proestrus Female Rats after Orofacial Varicella Zoster Injection

Hornung, Rebecca; Pritchard, Addison; Kinchington, Paul R.; Kramer, Phillip R.

doi:10.3390/ijms21165749

Cited by 9 publications

(8 citation statements)

References 52 publications

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“…previously in the amygdala (Liu et al, 2021;Stumpf & O'Brien, 1987) and its expression was shown to be elevated in proestrus rats during the pain response to chicken pox infection (Hornung et al, 2020) and S2), largely consistent with a previous report (Kim et al, 2017).…”

Section: Biological Insightssupporting

confidence: 90%

Multimodal mapping of cell types and projections in the central nucleus of the amygdala

Wang

Krabbe

Eddison

et al. 2022

Preprint

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The central nucleus of the amygdala (CEA) is a brain region that integrates external and internal sensory information and executes innate and adaptive behaviors through distinct output pathways. Despite its complex functions, the diversity of molecularly defined neuronal types in the CEA and their contributions to major axonal projection targets have not been examined systematically. Here, we performed single-cell RNA-sequencing (scRNA-Seq) to classify molecularly defined cell types in the CEA and identified marker-genes to map the location of these neuronal types usingexpansionassisted iterative fluorescence insituhybridization (EASI-FISH). We developed new methods to integrate EASI-FISH with 5-plex retrograde axonal labeling to determine the spatial, morphological, and connectivity properties of ∼30,000 molecularly defined CEA neurons. Our study revealed spatio-molecular organization of the CEA, with medial and lateral CEA associated with distinct cell families. We also found a long-range axon projection network from the CEA, where target regions receive inputs from multiple molecularly defined cell types. Axon collateralization was found primarily among projections to hindbrain targets, which are distinct from forebrain projections. This resource reports marker-gene combinations for molecularly defined cell types and axon-projection types, which will be useful for selective interrogation of these neuronal populations to study their contributions to the diverse functions of the CEA.

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Section: Biological Insightssupporting

confidence: 90%

Multimodal mapping of cell types and projections in the central nucleus of the amygdala

Wang

Krabbe

Eddison

et al. 2022

Preprint

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“…In female rats expression of Nrxn3α was elevated at proestrus in the central amygdala and the amount of transcript was correlated to the concentration of plasma estradiol ( Hornung et al, 2020 ). In this study attenuating Nrxn3 expression within the central amygdala increased VZV associated orofacial pain after VZV was injected into the vibrissae pad of the rat.…”

Section: Discussionmentioning

confidence: 99%

“…The pain response is due, in part, to expression of early viral proteins ( Guedon et al, 2014 ) and it has been shown that complete replication and production of new virus particles is not required for the pain response ( Warner et al, 2021 ). Recently our lab reported neurexin 3α (Nrxn3α) was expressed in the central amygdala and parabrachial and that expression differed during the estrous cycle in rats with VZV induced pain ( Hornung et al, 2020 ). Nrxn3α expression was elevated in the central amygdala of proestrus female rats vs. rats in diestrus.…”

Section: Introductionmentioning

confidence: 99%

Sex Differences in the Role of Neurexin 3α in Zoster Associated Pain

Kramer

Umorin

Hornung

et al. 2022

Front. Integr. Neurosci.

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Varicella zoster virus (VZV) induces orofacial pain and female rats show greater pain than male rats. During the proestrus phase of the estrous cycle the VZV induce pain response is attenuated in female rats. A screen of gene expression changes in diestrus and proestrus female rats indicated neurexin 3α (Nrxn3α) was elevated in the central amygdala of proestrus rats vs. diestrus rats. GABAergic neurons descend from the central amygdala to the lateral parabrachial region and Nrxn3α is important for presynaptic γ-Aminobutyric acid (GABA) release. Thus, we hypothesized that the reduced orofacial pain in male rats and proestrus female rats is the result of increased Nrxn3α within the central amygdala that increases GABA release from axon terminals within the parabrachial and inhibits ascending pain signals. To test this hypothesis Nrxn3 α expression was knocked-down by infusing shRNA constructs in the central amygdala. Then GABA release in the parabrachial was quantitated concomitant with measuring the pain response. Results revealed that knockdown of Nrxn3α expression significantly increases the pain response in both male rats and proestrus female rats vs. diestrus rats. GABA release was significantly reduced in the parabrachial of male and proestrus female rats after Nrxn3α knockdown. Neuronal activity of excitatory neurons was significantly inhibited in the parabrachial after Nrxn3α knockdown. These results are consistent with the idea that Nrxn3 within the central amygdala controls VZV associated pain by regulating GABA release in the lateral parabrachial that then modulates ascending orofacial pain signals.

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“…VZV parental Oka (pOka) is a wild-type varicella isolate from which the current live attenuated vaccines were derived [46]. It has been established that pOka can induce both mechanical and thermal hypersensitivity in rat models of PHN [31][32][33][34][35][36][37][38] and was used as a positive control in all studies. Recombinant viruses were derived from a pOka bacterial-artificial chromosome (BAC) which contains a self-excisable BAC replicon [47] that was subsequently corrected for two spurious mutations in the VZV ORF40 and ORF50 genes and contained an N terminal GFP reporter fused to ORF23 [48].…”

Section: Cells and Virusesmentioning

confidence: 99%

“…It was then demonstrated by multiple groups that Wistar and Sprague-Dawley rat strains inoculated with VZV at the footpad develop prolonged signs of pain that could serve as preclinical models for exploring mechanisms and treatment strategies for PHN [22]. The models involve subcutaneous inoculation of cell-associated VZV into the rat hind footpad [26][27][28][29][30][31][32] or more recently, the whisker pad [33][34][35][36][37][38]. While animals show no outward signs of skin infection, inflammatory response, or disease, they develop nocifensive behaviors lasting several weeks.…”

Section: Introductionmentioning

confidence: 99%

Varicella-zoster virus early infection but not complete replication is required for the induction of chronic hypersensitivity in rat models of postherpetic neuralgia

et al. 2021

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Herpes zoster, the result of varicella-zoster virus (VZV) reactivation, is frequently complicated by difficult-to-treat chronic pain states termed postherpetic neuralgia (PHN). While there are no animal models of VZV-induced pain following viral reactivation, subcutaneous VZV inoculation of the rat causes long-term nocifensive behaviors indicative of mechanical and thermal hypersensitivity. Previous studies using UV-inactivated VZV in the rat model suggest viral gene expression is required for the development of pain behaviors. However, it remains unclear if complete infection processes are needed for VZV to induce hypersensitivity in this host. To further assess how gene expression and replication contribute, we developed and characterized three replication-conditional VZV using a protein degron system to achieve drug-dependent stability of essential viral proteins. Each virus was then assessed for induction of hypersensitivity in rats under replication permissive and nonpermissive conditions. VZV with a degron fused to ORF9p, a late structural protein that is required for virion assembly, induced nocifensive behaviors under both replication permissive and nonpermissive conditions, indicating that complete VZV replication is dispensable for the induction of hypersensitivity. This conclusion was confirmed by showing that a genetic deletion recombinant VZV lacking DNA packaging protein ORF54p still induced prolonged hypersensitivities in the rat. In contrast, VZV with a degron fused to the essential IE4 or IE63 proteins, which are involved in early gene regulation of expression, induced nocifensive behaviors only under replication permissive conditions, indicating importance of early gene expression events for induction of hypersensitivity. These data establish that while early viral gene expression is required for the development of nocifensive behaviors in the rat, complete replication is dispensable. We postulate this model reflects events leading to clinical PHN, in which a population of ganglionic neurons become abortively infected with VZV during reactivation and survive, but host signaling becomes altered in order to transmit ongoing pain.

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Comparing Gene Expression in the Parabrachial and Amygdala of Diestrus and Proestrus Female Rats after Orofacial Varicella Zoster Injection

Cited by 9 publications

References 52 publications

Multimodal mapping of cell types and projections in the central nucleus of the amygdala

Multimodal mapping of cell types and projections in the central nucleus of the amygdala

Sex Differences in the Role of Neurexin 3α in Zoster Associated Pain

Varicella-zoster virus early infection but not complete replication is required for the induction of chronic hypersensitivity in rat models of postherpetic neuralgia

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