Investigation of changes in global gene expression in the frontal cortex of early-weaned and socially isolated
R Poletto1, J M Siegford, J P Steibel
1Animal Behavior and Welfare Group, Department of Animal Science, Michigan State University, 1287 Anthony Hall, East Lansing, MI 48824, USA.
Insights
Early weaning and social isolation in piglets alter stress-responsive gene expression in the frontal cortex. These changes impact genes crucial for neuronal function and development in young pigs.
Area of Science:
- Neuroscience
- Animal Science
- Molecular Biology
Background:
- Early life stress, such as early weaning, can profoundly affect brain development and function.
- The frontal cortex is critical for cognitive processes and behavior regulation.
- Understanding gene expression changes in response to early-weaning and social isolation is vital for animal welfare and developmental neuroscience.
Purpose of the Study:
- To investigate the hypothesis that early-weaned piglets exhibit aberrant gene expression in the frontal cortex.
- To examine the effects of early weaning and social isolation on stress-responsive gene expression in the porcine frontal cortex.
Main Methods:
- Gene expression profiling using cDNA microarray hybridizations on porcine brain tissue.
- Quantitative real-time polymerase chain reaction (Q-RT-PCR) to validate microarray findings.
- Comparison of gene expression between early-weaned and non-weaned piglets, with and without social isolation.
Main Results:
- 103 genes were differentially expressed (P < 0.05, fold change >1.25) between groups.
- 24 differentially expressed genes had known brain-related functions.
- Social isolation suppressed mRNA levels of specific genes (e.g., carboxypeptidase E, diazepam binding inhibitor) in both non-weaned and early-weaned piglets.
Conclusions:
- Early weaning and social isolation significantly impact gene expression in the frontal cortex of piglets.
- These alterations affect genes involved in neuronal function, development, and protection.
- Findings highlight the neurobiological consequences of early life stress in pigs.
Abstract:
We hypothesize that early-weaned piglets experience aberrant expression of stress-responsive genes in the frontal cortex, a key brain area involved in cognitive function and behavior organization. To test this hypothesis, female early-weaned piglets (EW; n = 6) were weaned 10 days after birth, while non-weaned piglets (NW; n = 6) were left with their dams. Half of EW (n = 3) and NW (n = 3) animals were socially isolated (SI) for 15 min at 12 days of age, when all animals (n = 12) were euthanized and tissue collected. The effects of EW and SI were examined by gene expression profiling using cDNA microarray hybridizations, generated from a porcine brain cDNA library. A total of 103 genes were differentially expressed (P < 0.05, fold change >1.25) among four direct comparisons. Forty-two genes had known functions, from which 24 showed relevant brain-related functions. Quantitative real-time polymerase chain reaction (Q-RT-PCR) was used to confirm regulation of expression of a subset of 6 genes with important brain functions, selected from the microarray outcomes. In non-weaned animals, a significant suppression of mRNA abundance for carboxypeptidase E, 14-3-3 protein and phosphoprotein enriched in astrocytes 15 kDa was observed in response to SI. Also, in early-weaned animals, diazepam binding inhibitor and actin-related protein 2/3 complex mRNA levels were suppressed in response to SI. Results suggest that social isolation of non- and early-weaned piglets may impact expression of genes involved in regulation of neuronal function, development, and protection in the frontal cortex of young pigs.
