Fig. 1

Fig. 1

Figure 1. Early brain BV regeneration occurs via iLV-to-BV transdifferentiation

(A) The ventral and dorsal views of zebrafish brain vasculature at larval stages, which include all the imaging areas of high magnification pictures. Green and red represent brain BVs and BLECs, respectively.

(B–D) Uninjured larvae controls (B), a portion of GFP+ vessels were positive for Dendra2 after Mtz treatment (C), which is shown in higher magnification in the framed area (arrowhead). (D) The statistics show ratios of the Dendra2+GFP+ vessels among GFP+ vessels (n = 15 larvae; ^∗∗∗, p < 0.0001).

(E and F) In contrast to the RFP+Alexa647+ BLECs in the uninjured control (E, arrows), the RFP+Alexa647+ iLVs gradually expressed Dendra2 from 2 dpt to 4 dpt after Mtz treatment (F, arrowheads). The Alexa647-IgG was injected before Mtz treatment. See also Video S1.

(G) Time-lapse imaging showed the real-time processes of iLV ingrowth and gain of Dendra2 fluorescence. The expression of Dendra2 became detectable from 60:00/60 hpt. Arrowheads indicate the transdifferentiating iLVs. The elapsed time is indicated in hours:minutes after 0 dpt. See also Video S2.

(H–J) BLECs were labeled by Kaede green at 1 dpt shortly before ingrowth (H). The photoconverted BLECs were marked by the white frame in (I) and enlarged in the right panels. At 4 dpt, one iLV derived from the Kaede-red BLECs expressed the BEC-specific CFP (J, arrowhead). See also Video S3.

Scale bar, 50 μm. See also Figures S1 and S2.

AMCtA, anterior (rostral) mesencephalic central artery; PCS, posterior (caudal) communicating segment; BCA, basal communicating artery; BA, basilar artery; CCtA, cerebellar central artery; CtA, central artery; CVP, choroidal vascular plexus; MMCtA, middle mesencephalic central artery; MsV, mesencephalic vein; MtA, metencephalic artery; PHBC, primordial hindbrain channel; PMCtA, posterior (caudal) mesencephalic central artery; BLECs, brain lymphatic endothelial cells.