Details

Autor(en) / Beteiligte

• Lynn, Sharon E.
• Kern, Michael D.
• Serrurier, Bridget
• Sirman, Aubrey
• Heidinger, Britt J.

Titel

Chill out: Environmentally relevant cooling challenge does not increase telomere loss during early life

Ist Teil von

• General and comparative endocrinology, 2022-12, Vol.329, p.114108-114108, Article 114108

Ort / Verlag

Elsevier Inc

Erscheinungsjahr

2022

Quelle

Access via ScienceDirect (Elsevier)

Beschreibungen/Notizen

• •Stress responses early in life can promote or mitigate cellular damage.•Previous work shows cooling initiates a stress response in altricial nestlings.•Experimental cooling did not affect telomere shortening of bluebird nestlings.•Larger broods and faster growth were associated with shorter telomeres.•Parental care may optimize stress responses to maximize fitness of young. In vertebrates, exposure to diverse stressors during early life activates a stress response that can initiate compensatory mechanisms or promote cellular damage with long-term fitness consequences. A growing number of studies associate exposure to stressors during early life with increased damage to telomeres (i.e., promoting the shortening of these highly conserved, repeating sequences of non-coding DNA at chromosome ends). However, some studies show no such relationship, suggesting that the nature, timing, and context of these challenges may determine the degree to which physiological mediators of the stress response act in a damage-mitigating or damage promoting way in relation to telomere dynamics. In free-living eastern bluebirds (Sialia sialis), we have previously demonstrated that bouts of offspring cooling that occur when brooding females leave the nest increase at least one such physiological mediator of the stress response (circulating glucocorticoids), suggesting that variation in patterns of maternal brooding may result in different impacts on telomere dynamics at a young age. Here we experimentally tested whether repeated bouts of ecologically relevant offspring cooling affected telomere dynamics during post-natal development. Rates of telomere shortening during the nestling stage were not affected by experimental cooling, but they were affected by brood size and the rate of growth during the nestling stage. Our data suggest that the effects of developmental stress exposure on offspring telomeres are often context-dependent and that not all challenges that increase physiological mediators of stress result in damage to telomeres. Under some conditions, physiological mediators of stress may instead act as protective regulators, allowing for optimization of fitness outcomes in the face of environmental challenges.