Expression and regulation of HSPB5 in the myometrium throughout pregnancy

The uterine smooth muscle or myometrium goes through phases of differentiation during pregnancy to become a powerful contractile tissue at term. Small Heat Shock proteins (sHSPs) are a family of ten small molecular weight proteins in mammals that are induced by many physiological stressors such as uterine stretch. Some sHSPs act as chaperones, but also others assist in cell death regulation, cytoskeleton rearrangements, and immune system activation. We examined the spatio-temporal expression of HSPB5 protein throughout gestation via immunoblot and immunofluorescence analysis, as well as the effect of uterine distension on myometrial HSPB5 protein expression using unilaterally pregnant rat models. HSPB5 protein expression significantly increased on day (d) 17 (p<0.05; vs all other timepoints) and levels steadily decreased thereafter through to postpartum (PP). In contrast, serine-59 phosphorylated (pSer59) HSPB5 protein detection was significantly increased from d19 through to PP (p