Figure 3.

HAS2 enzyme is upregulated in humans with IVH. A, Representative immunofluorescence of cryosections from 23 gw infant labeled with HAS1 (top) and HAS2 (bottom). Insets show high-magnification images. HAS2 immunoreactivity was strong in ganglionic eminence of infants with IVH and weak in infants without IVH. However, HAS1 was similarly expressed in infants with and without IVH. Note HAS1 and HAS2 are expressed on GFAP⁺ astrocytes (arrowheads) and a few O4⁺ OPCs. HAS1 immunoreactivities were weak to absent on DCX⁺ neurons, but HAS2 was expressed on DCX⁺ neurons (arrowheads). Scale bars: 20 μm. B, Western blot analyses were performed for HAS1, HAS2, and HAS3 on homogenates made from tissues taken from cortical plate (cortex), embryonic WM, and GEs of preterm infants with and without IVH, as indicated. The bar charts show mean ± SEM (n = 6 each). Values were normalized to β actin levels. HAS2 levels were elevated in the ganglionic eminence of infants with IVH compared to controls without IVH, but not HAS1 or HAS3. **p < 0.01 (no IVH vs IVH in the ganglionic eminence).