New neurons follow the flow of cerebrospinal fluid in the adult brain.
Alvarez-Buylla’s Lab)
(Abstract)
Science . Vol. 311. no. 5761, pp. 629 - 632 (2006) Перевод И.Г. Лильп (lilp@mail.ru) | |
) Рис.1. | Mapping of ependymal cell ciliary beating and CSF flow. (A to E) Intraventricular CSF flow in vivo recording by real-time, digitally subtracted radiography. (A) Schematic drawing shows the position where cannula was placed for injection of radiopaque contrast. Lateral ventricle, LV; olfactory bulb, OB; anterior, A; dorsal, D; ventral, V; posterior, P. (B) Mouse head radiogram before injection of contrast. (C) to (E) Serial radiograms were taken every 0.33 s. (C) At 0 s, (D) at 3.5 s, and (E) at 5.5 s. (See movie S1.) Dashed lines denote the lateral ventricle and cannula placement. Note how the contrast (arrowheads) moves along a dorsal corridor and then turns ventrally around the anterior horn (dashed arrow). The mean time of contrast movement to reach the anterior tip of the ventricle from the injection site (–1.0 mm relative to bregma) was 6.3 ± 0.8 s (SD) (n = 6). The site of the wall adhesion is marked by an asterisk. (F to H) Ependymal flow revealed by India ink placed [(F), arrow] onto exposed surface of the lateral wall of the lateral ventricle (n = 6). Note how ink moves along a dorsal corridor (G) and then turns ventrally (H) around the wall adhesion (asterisk). (See movie S2.) (I to L) Scanning electron micrographs showing orientation of ependymal cilia at various locations on the lateral wall of the lateral ventricle as indicated in (L). Cilia beat ventrally in the anterior part of the anterior horn (I), beat anteriorly in the dorsal anterior horn (J), and beat anterodorsally in the intermediate region dorsal to the choroid plexus (K). (L) Note how the direction of CSF flow (red) is similar to cell migration pattern (blue) (see Fig. 2) around the wall adhesion (asterisk). Scale bars: (B), 0.5 cm; (C) to (E), 0.15 cm; (F) to (H), 1 mm; (I) to (K), 10 µm. Pink denotes the location of choroid plexus ) Рис.2. | Mapping of cell migration in the SVZ. (A) Schematic sagittal view of adult mouse forebrain showing the lateral wall of the lateral ventricle, RMS, and the olfactory bulb. Arrows indicate direction of migration. Camera lucida drawing of the chains of neuroblasts in the SVZ is included [modified from (6)]. (B) Composite map of the direction of cell migration (from 25 animals) in the SVZ (delineated by green rectangles) and RMS. Each black arrow in the map indicates the orientation and length of the leading process of individual cells. Neuroblasts were labeled with a retrovirus encoding alkaline phosphatase (see inset for example). (C) Quantification of cell migration. The orientation of the leading process of each cell was used to determine the percentage of cells oriented in the direction of the olfactory bulb (defined as 0°) [see compasses in (B)]. In the dorsal SVZ and in the RMS, 0° was defined in the direction of the olfactory bulb and parallel to the longitudinal array of chains. Cells pointing in the reverse direction were considered oriented at 180°. For the anterior SVZ, 0° orientation was defined dorso-anteriorly in the direction of the longitudinal array of chains leading to the olfactory bulb. Note in the histogram how the majority of cells in the dorsal SVZ and RMS have a 0° orientation (toward the olfactory bulb). In contrast, the majority of cells in the anterior SVZ are pointing ventrally (180°) away from the RMS and olfactory bulb. The total numbers of cells counted in each region: RMS, 184; anterior SVZ, 111; and dorsal SVZ, 303. ) Рис.3. | Cell migration defects in theTg737orpk mutant. (A and B) Whole mounts of the lateral walls of the lateral ventricle stained with antibody against PSA-NCAM. A well-organized longitudinal array of chains (arrowheads) was observed in the wild-type brain (WT) (A) but not in the Tg737orpk/orpk mutant (B). Higher magnification views of the dorsal region marked by squares (A) and (B) are shown in the insets to the right. (C to E) Normal cilia are required for rostral migration of endogenous neuroblasts. Sagittal sections of wild-type (C) and Tg737orpk (D) olfactory bulbs 5 days after injection of alkaline phosphatase–encoding retrovirus into the SVZ. (E) The number of alkaline phosphatase+ cells (means ± SD) reaching the olfactory bulb in the Tg737orpk/orpk mice was significantly smaller than in the wild type (P = 0.0004, t test). Total number of cells counted: wild type, 396 (n = 3); mutant, 112 (n = 3). (F) Tg737orpk/orpk mutant neuroblasts can migrate normally in the wild-type brain. SVZ cells from wild-type or Tg737orpk/orpk mutant mice carrying GFP were grafted into the SVZ of wild-type brains. (See fig. S4.) The histogram shows the number of GFP+ cells (means ± SD) in the olfactory bulbs 5 days (n = 4) and 16 days (n = 4) after transplantation. No significant difference was observed (P = 0.7763 at day 5 and 0.422 at day 16, t test). (G) Wild-type neuroblasts failed to migrate normally in the Tg737orpk/orpk mutant brain. GFP-labeled SVZ cells from wild-type mice were grafted into the SVZ of wild-type and Tg737orpk/orpk mutant mice. (See fig S4.) The histogram shows the number of GFP+ cells in the olfactory bulbs 5 days after transplantation (means ± SD) (n = 4). The number of wild-type cells reaching the olfactory bulb in the Tg737orpk/orpk brain was significantly smaller than in the wild type to wild type transplantation controls (P = 0.048, t test). OB, olfactory bulb. Scale bars: (A) and (B), 1 mm; (C) and (D), 50 µm ) Рис.4. | Slit2-AP concentration gradient formation in the SVZ. (A to F) The Slit2-AP fusion protein was infused into the caudal lateral ventricle close to the choroid plexus in wild-type [(A) to (D)] (n = 5) and Tg737orpk mutant (F) (n = 3) brains. Whole mounts of the lateral ventricular wall (anterior horn) [(A), (E), and (F)] or coronal sections [(B) to (D)] were stained for alkaline phosphatase enzyme activity 24 hours after the beginning of infusion. (E) Phosphate-buffered saline injection resulted in no signal (n = 1). (B) to (D) correspond to three different rostrocaudal levels of an infused brain sectioned in the coronal plane as shown approximately by the dotted lines in (A). Slit2-AP was deposited in a gradient, with the highest alkaline phosphatase activity detected in the caudal and dorsal SVZ. (F) Injection of Slit2-AP into the caudal lateral ventricle of Tg737orpk mutants did not result in the formation of this gradient. (G) Slit1/2 mutant (n = 5) or wild-type (n = 4) choroid plexuses were transplanted dorsal to the RMS. (See fig. S5.) As a control, meninges (n = 4) were grafted in the same location. One month later, alkaline phosphatase–encoding retrovirus was injected into the SVZ. Five days after injection, alkaline phosphatase+ cells (means ± SD) were counted. In controls, most of the alkaline phosphatase–labeled cells have reached the olfactory bulb, with few cells remaining in the SVZ and RMS. The pattern was reversed in the choroid plexus–grafted (CP) animals; most of the cells failed to reach the olfactory bulb and remained in the SVZ. This repulsive effect of the choroid plexus graft was partially reversed in the Slit1/2 mutant (P = 0.0068, t test). OB, olfactory bulb. Scale bars: (A), (E), and (F), 1 mm; (B) to (D), 0.5 mm Табл.1 Название | |