Biology subjects

Lintz, T.

Publications and source records attributed to Lintz, T..

4 recordsLinked to original sources

bioRxiv2025

Cornichon Homolog-3 (Cnih3) deletion impairs spatial memory, reward-cue association, and fentanyl self-administration behavior.

Opioid misuse remains rampant as new synthetic opioids reach the market. Large-scale genetic tools like the GWAS identify previously unrecognized targets and biomarkers in opioid misuse with hopes of combating the opioid epidemic. One such target is the AMPAR auxiliary protein Cornichon Homolog-3 (human analog: CNIH3, mouse analog: Cnih3), which determines AMPAR subunit composition and kinetics. Though CNIH3 was identified as a gene of interest in OUD, its role in opioid use and accompanying risk factors has not been studied. Using mice with Cnih3 deletion, we assess the role of CNIH3 in risk factors for opioid use, cognition, and opioid use itself. We find that Cnih3 deletion moderately impairs spatial memory, reward-cue association, and reversal learning. Cnih3 deletion also impairs fentanyl-cue association and blunts fentanyl intake during IVSA. We use principal component analysis to pinpoint the dimensions in which Cnih3 deletion impacts behavior in an unbiased manner. Additionally, we identify in previously published human data that single-nucleotide polymorphisms are more protective against progression to daily opioid use in women than in men, suggesting a potential sex-specific role of CNIH3. These findings highlight an important role of CNIH3 in opioid use through learning and memory processes that may differ between males and females.

neuroscience↗

bioRxiv2024

Peripheral opioid receptor antagonism alleviates fentanyl-induced cardiorespiratory depression and is devoid of aversive effects

Millions of Americans suffering from Opioid Use Disorders (OUD) face a high risk of fatal overdose due to opioid-induced respiratory depression (OIRD). Fentanyl, a powerful synthetic opioid, is a major contributor to the rising rates of overdose deaths. Reversing fentanyl overdoses has proved challenging due to its high potency and the rapid onset of OIRD. We assessed the contributions of central and peripheral mu opioid receptors (MORs) in mediating fentanyl-induced physiological responses. The peripherally restricted MOR antagonist naloxone methiodide (NLXM) both prevented and reversed OIRD to a degree comparable to that of naloxone (NLX), indicating substantial involvement of peripheral MORs to OIRD. Interestingly, NLXM-mediated OIRD reversal did not produce aversive behaviors observed after NLX. We show that neurons in the nucleus of the solitary tract (nTS), the first central synapse of peripheral afferents, exhibit a biphasic activity profile following fentanyl exposure. NLXM pretreatment attenuates this activity, suggesting that these responses are mediated by peripheral MORs. Together, these findings establish a critical role for peripheral MORs, including ascending inputs to the nTS, as sites of dysfunction during OIRD. Furthermore, selective peripheral MOR antagonism could be a promising therapeutic strategy for managing OIRD by sparing CNS-driven acute opioid-associated withdrawal and aversion observed after NLX. Significance StatementIn this study, we compare the central versus peripheral components underlying fentanyl-induced cardiorespiratory depression to prevent overdose deaths. Our data indicate that these effects are, at least partially, due to the activation of mu opioid receptors present in peripheral sites. These findings provide insight into peripheral contributions to fentanyl-induced overdoses and could potentially lead to the development of treatments selectively targeting the peripheral system, sparing individuals from the CNS-driven acute opioid withdrawal generally observed with the use of naloxone.

physiology↗

bioRxiv2022

Typical hippocampal transcriptional response across estrous is dysregulated by Cnih3 gene deletion

The hippocampus is a critical brain region for coordinating learning, memory, and behavior. In females, the estrous cycle alters these functions through steroid hormone activity, with well-characterized effects on cellular physiology and behavior. However, the molecular basis of these outcomes has not been systematically explored. Therefore, we profiled the transcriptome of dorsal hippocampi from female mice in each estrous cycle stage, and contrasted it with that of males. We identify only subtle sex differences in gene expression between the sexes on average, yet comparing males to individual estrous stages reveals up to thousands of genes deviating from male expression patterns at specific estrous stages. These estrous-responsive genes are especially enriched in gene markers of oligodendrocytes and the dentate gyrus, and in functional gene sets relating to estrogen response, potassium channels, and synaptic gene splicing. Next we profiled Cnih3 knockouts across estrous to provide insight into their previously reported estrous-dependent phenotypes in hippocampal synaptic plasticity, composition, and learning and memory behaviors. Surprisingly, Cnih3 knockouts showed far broader transcriptomic differences between estrous cycle stages and males. Moreover, Cnih3 knockout drove subtle but extensive expression changes accenting sex differential expresssion at diestrus and estrus. Altogether, our profiling constitutes both a resource characterizing estrous-specific gene expression patterns in the adult hippocampus, which can provide insights into mechanisms of sex differential neuropsychiatric functions and dysfunctions, while also highlighting roles of Cnih3 as a buffer against transcriptional effects of estrous and providing insights into the molecular mechanisms that may underlie estrous-dependent phenotypes with its loss.

neuroscience↗

bioRxiv2021

Prenatal opioid exposure inhibits microglial sculpting of the dopamine system during adolescence

The current opioid epidemic has dramatically increased the number of children who are prenatally exposed to opioids, including oxycodone. A number of social and cognitive abnormalities have been documented in these children as they reach young adulthood. However, little is known about the mechanisms underlying developmental effects of prenatal opioid exposure. Microglia, the resident immune cells of the brain, respond to acute opioid exposure in adulthood. Moreover, microglia are known to sculpt neural circuits during healthy development. Indeed, we recently found that microglial phagocytosis of dopamine D1 receptors (D1R) in the nucleus accumbens (NAc) is required for the natural developmental decline in NAc-D1R that occurs between adolescence and adulthood in rats. This microglial pruning occurs only in males, and is required for the normal developmental trajectory of social play behavior. However, virtually nothing is known as to whether this developmental program is altered by prenatal exposure to opioids. Here, we show in rats that maternal oxycodone self-administration during pregnancy leads to reduced adolescent microglial phagocytosis of D1R and subsequently higher D1R density within the NAc in adult male, but not female, offspring. Finally, we show that prenatal opioid exposure abolishes the extinction of oxycodone-conditioned place preference in these male offspring. This work demonstrates for the first time that microglia play a key role in translating prenatal opioid exposure to long-term changes in neural systems and behavior. HighlightsO_LIPrenatal opioid exposure decreases offspring viability and body weight in males and females C_LIO_LIPrenatal opioid exposure decreases microglial phagocytosis of D1R in the nucleus accumbens in males only C_LIO_LIPrenatal opioid exposure increases nucleus accumbens dopamine D1 receptor expression in males but not females C_LIO_LIAdult males fail to extinguish oxycodone-conditioned place preference following prenatal oxycodone exposure C_LI

neuroscience↗