Figure 10.

IVH induces TSG-6 activity and synthesis of HC–HA complexes. A, B, Representative Western blot analyses performed on tissues from embryonic WM and GEs of preterm infants with and without IVH using IαI specific antibody. Homogenates were digested with hyaluronidase and were run with undigested samples in alternate lanes. The 250, 150, and 85 kDa bands indicate IαI, pre-IαI, and free HCs, respectively. Data are mean ± SEM (n = 4 each). Note that the HC–HA concentration is higher in GEs of infants with IVH compared to controls without IVH. C, D, Typical Western blot analyses performed on tissues from WM and GEs of premature infants with and without IVH using IαI antibody. HA oligosaccharide (10 monosaccharides size) was added to each homogenate in C. Some homogenates were treated with human recombinant TSG-6 as a positive control. Data are mean ± SEM (n = 4 each). Note that the HC–HA concentration is higher in GEs of infants with IVH compared to controls. E, Representative Western blot analyses performed on tissues from GEs of preterm infants with IVH using an Iα1-specific antibody. Homogenates were digested with hyaluronidase; treated with HA10, TSG-6, or both TSG and HA10; and incubated for 24 (top) or 72 h (bottom). F, Schematic showing TSG-6-mediated enzymatic transfer of HCs from IαI to HA, forming the HC–HA complex (top), and that these HCs can be irreversibly swapped from HC–HA onto HA10. G, Data are shown as mean ± SEM (n = 5 each). TSG-6 mRNA expressions were higher in IVH compared to controls at day 3, but not at day 7.