Pre-reproductive stress in adolescent female rats alters oocyte microRNA expression and offspring phenotypes: pharmacological interventions and putative mechanisms

Hiba Zaidan,Inna Gaisler-Salomon,Dalia Galiani

doi:10.1038/s41398-021-01220-1

Hiba Zaidan, Inna Gaisler-Salomon + Show 1 more

Open Access

https://doi.org/10.1038/s41398-021-01220-1

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Abstract

Pre-reproductive stress (PRS) to adolescent female rats alters anxiogenic behavior in first (F1)- and second-generation (F2) offspring and increases mRNA expression of corticotropin-releasing factor receptor type 1 (Crhr1) in oocytes and in neonate offspring brain. Here, we ask whether the expression of Crhr1 and Crhr1-targeting microRNA is altered in brain, blood, and oocytes of exposed females and in the brain of their neonate and adult F1 and F2 offspring. In addition, we inquire whether maternal post-stress drug treatment reverses PRS-induced abnormalities in offspring. We find that PRS induces a selective increase in Crhr1-targeting mir-34a and mir-34c in blood and oocytes, while non-Crhr1 microRNA molecules remain unaltered. PRS induces similar microRNA changes in prefrontal cortex of F1 and F2 neonates. In adult animals, cortical Crhr1, but not mir-34, expression is affected by both maternal and direct stress exposure. Post-PRS fluoxetine (FLX) treatment increases pup mortality, and both FLX and the Crhr1 antagonist NBI 27914 reverse some of the effects of PRS and also have independent effects on F1 behavior and gene expression. PRS also alters behavior as well as gene and miRNA expression patterns in paternally derived F2 offspring, producing effects that are different from those previously found in maternally derived F2 offspring. These findings extend current knowledge on inter- and trans-generational transfer of stress effects, point to microRNA changes in stress-exposed oocytes as a potential mechanism, and highlight the consequences of post-stress pharmacological interventions in adolescence.

Highlights

Exposure to an unpredictable, adverse environment has long-term effects on health, behavior, and endocrine function
In a recent series of studies, we investigated the impact of mild, chronic pre-reproductive stress (PRS) to adolescent female rats on F1 and F2 offspring behavior, HPA axis function, prefrontal cortex (PFC) morphology, and gene expression patterns[28,29,30,31]
Examining the impact of maternal NBI or FLX treatment on serum CORT in control and Pre-reproductive stress (PRS)-exposed females and their offspring, we found that maternal NBI treatment, which reversed the impact of PRS on serum CORT in F0, reversed the 3.5-fold PRS-induced increase in CORT observed in behaviorally naïve F1 offspring[28], whereas FLX administration had the opposite effect and increased CORT by >8 fold (Table S9)

Summary

Methods

Animals Adolescent female Sprague-Dawley rats and the adult males used for mating were purchased from Envigo (Jerusalem). Adolescent (P45) female rats (F0) were randomly assigned to control (C) or PRS groups. PRS rats were exposed to a 7-day chronic unpredictable stress (CUS) protocol[28,29,30,31,47]. To produce the F2 generation, we bred F1-C and F1-PRS behaviorally naïve males with naïve females. In F2, we examined their male and female offspring (F2-C, F2-PRS). F1: Male and female adult progeny were randomly divided into low- and high-stress exposure. ‘High-stress’ rats were tested in the elevated plus maze (EPM) followed 24 h later by the fear conditioning and extinction test. F2: Male and female adult progeny were tested in the OF, NOR, and social preference (SP) tests.

C Week 8 P60

Results

Discussion