Fig. 1.

SOD1^G93A GRP transplants survive and differentiate into astrocytes. (A) Transverse cross-sectional illustration of cervical spinal cord demonstrating GRP transplantation into cervical ventral horn. Boxed area in A is shown in B. (B) Transplants were visualized with an antibody against mouse membrane marker M2. Asterisk indicates transplant site. Inset: Cells harboring the SOD1^G93A mutation or SOD1^WT were distinguished from WT cells by using an antibody against human SOD1 (hSOD1). (C and D) Representative immunoblots and densitometric analysis of hSOD1 levels expressed by SOD1^G93A, SOD1^WT, and WT GRPs in vitro and in vivo (cervical cord), as well as levels expressed in cervical cord of SOD1^G93A rats (TG-SOD1^G93A) and SOD1^WT mice (TG-SOD1^WT) for comparison (in D: Tx, transplanted rats; TG, transgenic animals). Quantification of GRP differentiation at 1 wk (E) and 3 mo (F) after transplant depicts the efficient transition from immature to mature phenotypes. At 1 wk, transplanted M2⁺ SOD1^G93A cells were still nestin⁺ GRPs (E and G). At 3 mo, most M2⁺ SOD1^G93A GRPs expressed the APC marker CD44 (F and H) and differentiated into GFAP⁺ astrocytes (F and I). NPCs, neural precursor cells; OPCs, oligodendrocyte precursor cells; APCs, astrocyte-restricted precursor cells; Astro's, astrocytes; Oligo's, oligodendrocytes. Error bars represent SEM. (Scale bars, 200 μm in B, 10 μm in B, Inset and E–G.)