Refine
Document Type
- Article (1)
- Doctoral Thesis (1)
Language
- English (2)
Has Fulltext
- yes (2)
Is part of the Bibliography
- no (2)
Keywords
- oligodendrocyte precursor cells (2) (remove)
Oxygen causes white matter damage in preterm infants and male sex is a major risk factor
for poor neurological outcome, which speculates the role of steroid hormones in sex-based differences.
Preterm birth is accompanied by a drop in 17β-estradiol (E2) and progesterone along with increased
levels of fetal zone steroids (FZS). We performed a sex-based analysis on the FZS concentration
differences in urine samples collected from preterm and term infants. We show that, in preterm
urine samples, the total concentration of FZS, and in particular the 16α-OH-DHEA concentration, is
significantly higher in ill female infants as compared to males. Since we previously identified Nup133
as a novel target protein affected by hyperoxia, here we studied the effect of FZS, allopregnanolone
(Allo) and E2 on differentiation and Nup133 signaling using mouse-derived primary oligodendrocyte
progenitor cells (OPCs). We show that the steroids could reverse the effect of hyperoxia-mediated
downregulation of Nup133 in cultured male OPCs. The addition of FZS and E2 protected cells from
oxidative stress. However, E2, in presence of 16α-OH-DHEA, showed a negative effect on male
cells. These results assert the importance of sex-based differences and their potential implications in
preterm stress response.
Hyperoxia is a well-known cause of cerebral white matter injury in preterm infants with male sex being an independent and critical risk factor for poor neurodevelopmental outcome. We investigated the underlying mechanisms behind such a sex dependent difference in oligodendrocyte progenitor cells (OPCs). Our findings demonstrate that oxidative stress severely affects cellular functions related to energy metabolism, stress response, and maturation in male derived oligodendrocyte progenitor cells (OPCs) whereas the female cells remain largely unaffected. This impairment of maturation is accompanied by the downregulation of nucleoporin and nuclear lamina proteins. We identify Nup133, which regulates OPC maturation as a major target protein affected by hyperoxia in male cells and that this differential response is mediated by an inverse Nup133 regulation in the male and female cells. It also regulates mitochondrial function and oxidative stress response through its downstream target Nuclear respiratory factor 1 (Nrf1). Additionally, the presence of 17-β estradiol and higher amounts of fetal zone steroids (precursors for maternal estrogen synthesis during fetal development) confer resistance to the female cells mediated by the estrogen receptor alpha (ERα) along with Nup133. Both Nup133 and ERα regulate mitochondrial function and oxidative stress response by transcriptional regulation of Nrf1. These findings establish prominent sex based differences and the molecular mechanisms involved in differential response of OPCs towards oxidative stress and the important role of Nup133 in mediating a severe negative outcome in the male cells.