Regulation of liver regeneration by bone morphogenetic proteins (BMPs) in zebrafish

• Main Authors: Meng-Che Chang, 張孟哲
• Other Authors: Wen-Pin Wang
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/80720198067643642010

碩士 === 慈濟大學 === 分子生物暨人類遺傳學系碩士班 === 100 === Several signaling pathways have been reported to play key roles during liver regeneration after partial hepatectomy (PH). In this study, we focus on bone morphogenetic protein (Bmp) and fibroblast growth factor (Fgf) sinaging pathways. Two different PH models, 1/12PH (1/4 of ventral lobe was removed) and 1/3PH (whole ventral lobe was removed), were established using the Tg(lfabp:egfp) zebrafish with liver- specific expression of GFP. Using 1/12PH, a local growth of liver tissue was observed after 5 days morphologically. Using 1/3PH, incised liver lobe did not regrow but compensatory growth of the other two dorsal lobes was detected by PCNA immunochemical staining after 3 days. We used the Tg(hsp:noggin3) fish for liver regeneration. When heat shock (HS) was performed after 1/12PH for 5 days, the local liver growth was inhibited, compared to the non-HS and WT fish. Furthermore, PCNA signal was reduced in Tg(hsp:noggin3) fish after HS. We also used Tg(hsp70:bmp2b) fish which expressed Bmp2b after HS for liver regeneration. However, we could not detect the different local growth between WT and transgenic fish at 5 days after HS in 1/12PH. Similar approach was applied to Tg(lfabp:dnfgfr1) fish with expression of dominant negative (dn) Fgfr1 to inhibite Fgf signaling in liver, and regenerative defect was detected. We analyzed the expression of proliferation markers (cyclinD, cyclinE, cdk2, pcna and uhrf1), regenerative genes (plk1, hsp60 and gremlin) and Bmp–related genes (bmp2a, bmp2b, bmpr1aa, bmpr1bb and noggin3) by RT-PCR/QRT-PCR in WT fish at 3 days after 1/3PH. Expression of these genes were greatly changed, especially for bmp2b and bmpr1aa. Expression of Fgf-related genes (fgfr2c, fgf2, sprouty2, pea3, erm) were also increased. Importantly, the increased expression of proliferation markers, regenerative genes, Bmp-related genes and Fgf-related genes were impaired in Tg(hsp:noggin3) fish after HS. To sum up, these results highly suggest that Bmp signaling has critical roles in liver regeneration of zebrafish. Besides that, Bmp signaling may act at upstream of Fgf pathway for the process.