Biology subjects

Miracle, S. A.

Publications and source records attributed to Miracle, S. A..

4 recordsLinked to original sources

bioRxiv2024

The acoustic properties, syllable structure, and syllable sequences of ultrasonic vocalizations (USVs) during neonatal opioid withdrawal in FVB/N mouse substrains

Concomitant with the opioid epidemic, there has been a rise in pregnant women diagnosed with opioid use disorder and cases of infants born with neonatal opioid withdrawal syndrome (NOWS). NOWS refers to signs and symptoms following cessation of prenatal opioid exposure that comprise neurological, gastrointestinal, and autonomic system dysfunction. A critical indicator of NOWS severity is excessive, high-pitched crying. However, NOWS evaluation is, in large part, subjective, and additional cry features may not be easily recognized during clinical assessment. Thus, there is a need for more objective measures to determine NOWS severity. We used a third trimester-approximate opioid exposure paradigm to model NOWS traits in genetically similar inbred substrains of FVB/N mice (NJ, NCrl, NHsd, and NTac). Pups were injected twice daily from postnatal day 1 (P1) to P14 with morphine (10 mg/kg, s.c.) or saline (20 ml/g, s.c.). Because there were only very minor substrain differences in spontaneous withdrawal-induced ultrasonic vocalization (USV) profiles, we collapsed across substrains to evaluate the effects of morphine withdrawal on additional USV properties. We identified syllable sequences unique to morphine-withdrawn and saline-control FVB/N pups on P7 and P14. We also observed an effect of spontaneous morphine withdrawal on the acoustic properties of USVs and specific syllables on P7 and P14. Multiple withdrawal traits correlated with some acoustic properties of USVs and syllable type emission in morphine-withdrawn FVB/N pups on P7 and P14. These data provide an in-depth investigation of mouse USV syllable profiles and acoustic features during spontaneous neonatal opioid withdrawal in mice.

animal behavior and cognition↗

bioRxiv2024

Validation studies and multi-omics analysis of Zhx2 as a candidate quantitative trait gene underlying brain oxycodone metabolite (oxymorphone) levels and behavior

Sensitivity to the subjective reinforcing properties of opioids has a genetic component and can predict addiction liability of opioid compounds. We previously identified Zhx2 as a candidate gene underlying increased brain concentration of the oxycodone (OXY) metabolite oxymorphone (OMOR) in BALB/cJ (J) versus BALB/cByJ (By) females that could increase OXY state-dependent reward. A large structural intronic variant is associated with a robust reduction of Zhx2 expression in J mice, which we hypothesized enhances OMOR levels and OXY addiction-like behaviors. We tested this hypothesis by restoring the Zhx2 loss-of-function in Js (MVKO) and modeling the loss-of-function variant through knocking out the Zhx2 coding exon (E3KO) in Bys and assessing brain OXY metabolite levels and behavior. Consistent with our hypothesis, Zhx2 E3KO females showed an increase in brain OMOR levels and OXY-induced locomotor activity. However, contrary to our hypothesis, state-dependent expression of OXY-CPP was decreased in E3KO females and increased in E3KO males. We also overexpressed Zhx2 in the livers and brains of Js and observed Zhx2 overexpression in select brain regions that was associated with reduced OXY state-dependent learning. Integrative transcriptomic and proteomic analysis of E3KO mice identified astrocyte function, cell adhesion, extracellular matrix properties, and endothelial cell functions as pathways influencing brain OXY metabolite concentration and behavior. These results support Zhx2 as a quantitative trait gene underlying brain OMOR concentration that is associated with changes in OXY behavior and implicate potential quantitative trait mechanisms that together inform our overall understanding of Zhx2 in brain function.

neuroscience↗

bioRxiv2024

Spectrotemporal profiling of ultrasonic vocalizations during neonatal opioid withdrawal reveals a kappa opioid receptor component in female mice

RationaleOpioid use during pregnancy can lead to negative infant health outcomes, including neonatal opioid withdrawal syndrome (NOWS). NOWS comprises gastrointestinal, autonomic nervous system, and neurological dysfunction that manifest during spontaneous withdrawal. Variability in NOWS severity necessitates a more individualized treatment approach. Ultrasonic vocalizations (USVs) in neonatal mice are emitted in isolation as a stress response and are increased during opioid withdrawal, thus modeling a negative affective state that can be utilized to test new treatments. ObjectivesWe sought to identify the behavioral and USV profile, brainstem transcriptomic adaptations, and role of kappa opioid receptors in USVs during neonatal opioid withdrawal. MethodsWe employed a third trimester-approximate opioid exposure model, where neonatal inbred FVB/NJ pups were injected twice-daily with morphine (10mg/kg, s.c.) or saline (0.9%, 20 ul/g, s.c.) from postnatal day(P) 1 to P14. This protocol induces reduced weight gain, hypothermia, thermal hyperalgesia, and increased USVs during spontaneous morphine withdrawal. ResultsOn P14, there were increased USV emissions and altered USV syllables during withdrawal, including an increase in Complex 3 syllables in FVB/NJ females (but not males). Brainstem bulk mRNA sequencing revealed an upregulation of the kappa opioid receptor (Oprk1), which contributes to withdrawal-induced dysphoria. The kappa opioid receptor (KOR) antagonist, nor-BNI (30 mg/kg, s.c.), significantly reduced USVs in FVB/NJ females, but not males during spontaneous morphine withdrawal. Furthermore, the KOR agonist, U50,488h (0.625 mg/kg, s.c.), was sufficient to increase USVs on P10 (both sexes) and P14 (females only) in FVB/NJ mice. ConclusionsWe identified an elevated USV syllable, Complex 3, and a female-specific recruitment of the dynorphin/KOR system in increased USVs associated with neonatal opioid withdrawal severity.

neuroscience↗

bioRxiv2024

Peripheral opioid tolerance involves skin keratinocytes and platelet-derived growth factor type B signaling

Opioid analgesic tolerance drives dose escalation which hampers the therapeutic utility of opioids by increasing centrally mediated deleterious side-effects, including respiratory depression or addiction. Peripheral opioid delivery provides a safer, effective alternative to systemic delivery by avoiding centrally mediated opioid side-effects. However, tolerance still occurs peripherally via mechanisms that remain unknown. Centrally, activation of the mu-opioid receptor (MOPr) by opioids induces release of platelet-derived growth factor-B (PDGF-B); and inhibition of PDGF receptor beta (PDGFR{beta}) prevents opioid tolerance. In the periphery, MOPr and PDGF-B are expressed in keratinocytes, and PDGFR{beta} is expressed in peripheral sensory neurons (PSNs), which are involved in tolerance. Previous studies showed that optogenetic stimulation of keratinocytes modulates PSNs via release of keratinocyte-derived factors. Thus, we hypothesized that mechanisms of peripheral opioid tolerance involve keratinocytes and PDGFR{beta} signaling. Using behavioral pharmacology, optogenetics and imaging in mice, we found that selective inhibition of peripheral PDGFR{beta} prevents peripheral morphine tolerance caused by repeated intraplantar (i.pl.) morphine injections. In addition, we show that PDGF-B is both necessary and sufficient to cause peripheral morphine tolerance. Repeated peripheral morphine injections lead to an increase in PDGF-B mRNA in MOPr-expressing keratinocytes and induce changes in the biophysical properties of keratinocytes as measured by patch-clamp electrophysiology. In parallel, we discovered that repeated optogenetic activation of keratinocytes is sufficient to induce peripheral morphine tolerance in a PDGF-B/PDGFR{beta}-dependent manner. Together, we show a novel epithelial-neuronal communication mechanism that incorporates keratinocytes and PDGF-B/PDGFR{beta} to mediate peripheral opioid tolerance, opening the door to safer, more effective pain therapeutics. Significance StatementPeripheral opioids are a safer alternative to systemic opioids. However, peripheral tolerance leads to reduction of analgesia over time, hampering clinical use of peripheral opioids. Here, we highlight a novel epithelial-neuronal communication mechanism that mediates peripheral tolerance. We discovered that intraplantar (i.pl.) morphine injections in mice cause peripheral tolerance via release of platelet-derived growth factor type B (PDGF-B) and activation of platelet-derived growth factor beta (PDGFR{beta}). We find that morphine i.pl. increases PDGF-B in mu-opioid receptor-expressing keratinocytes, which could be released to activate PDGFR{beta} in cutaneous nociceptor endings to mediate peripheral tolerance. Moreover, we show that photostimulation of keratinocytes is sufficient to cause peripheral tolerance in a PDGF-B/PDGFR{beta}-manner. Thus, keratinocytes and PDGF-B are new promising targets for peripheral opioid tolerance.

neuroscience↗