# Role of the gut microbiome in prolonged pain hypersensitivity following neonatal morphine exposure

> **NIH NIH F31** · UNIVERSITY OF MIAMI SCHOOL OF MEDICINE · 2024 · $48,974

## Abstract

Project Summary
In a murine model, neonatal morphine exposure (NME) results in prolonged pain hypersensitivity in
adolescence and adulthood; however, the underlying mechanisms are not fully understood. In adults, morphine
exposure has been found to alter the gut microbiome leading to gut dysbiosis. Gut dysbiosis has been
associated with microglial activation and neuroinflammation, which are critical in the initiation and persistence
of several pathological pain states. Activation of the microglia in the midbrain periaqueductal gray (PAG) and
spinal cord has been found to be heavily implicated in the development of the opioid-induced hypersensitivity
to pain. I recently showed that NME resulted in long-term gut dysbiosis persisting in adolescence and into
adulthood. However, the role of the gut microbiome, in particular NME-induced gut dysbiosis, have not yet
been investigated in prolonged pain hypersensitivity following NME. Therefore, the goal in this study is to
investigate the role of the gut microbiome in driving prolonged hypersensitivity to pain following NME. The
overarching hypothesis is that NME results in prolonged pain hypersensitivity by inducing long-lasting
alterations to the gut microbiome and driving persistent neuroinflammation in the microglia. To test this
hypothesis, in specific aim 1, the causal role of the gut microbiome in driving prolonged hypersensitivity to pain
will be investigated using Fecal Microbial Transplantation (FMT) of a dysbiotic microbiome from NME-mice
(donor) into naïve age-matched mice (recipient) to test whether an NME-microbiome alone results in pain
hypersensitivity. Furthermore, probiotics will be administered during the NME period to rescue the NME-
induced dysbiosis and to investigate whether a probiotic intervention can attenuate pain hypersensitivity
following NME. To elucidate the underlying molecular mechanisms, aim 2 will seek to establish that NME-
induced dysbiosis modulates microglial activation in regions that are essential for the processing and
modulation of pain, in particular the PAG and spinal cord, which drives pain hyper-sensitivity. Thus, using
immunohistochemistry, the activation status of the microglia in the PAG and spinal cord of NME-off springs will
be assessed. Additionally, the levels of released pro-inflammatory and nociceptive markers will be assessed
using RT-qPCR for mRNA determination and a Multiplex bead array for protein determination. Tissues from
the mice with manipulated microbiome generated in aim 1 will also be investigated to implicate the gut
microbiome. Finally, to further establish the involvement of the microglia on prolonged pain hypersensitivity, the
microglia of NME-off springs will be depleted during adolescence and adulthood with the CSF1R antagonist,
(PLX) 5622. Pain sensitivity will be tested following the short-term microglial depletion. Overall, this study will
advance our current understanding of the mechanisms driving hypersensitivity to pain follow...

## Key facts

- **NIH application ID:** 10900887
- **Project number:** 1F31DA059204-01A1
- **Recipient organization:** UNIVERSITY OF MIAMI SCHOOL OF MEDICINE
- **Principal Investigator:** Danielle Antoine
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $48,974
- **Award type:** 1
- **Project period:** 2024-07-01 → 2025-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10900887

## Citation

> US National Institutes of Health, RePORTER application 10900887, Role of the gut microbiome in prolonged pain hypersensitivity following neonatal morphine exposure (1F31DA059204-01A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10900887. Licensed CC0.

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