- 作者: Jenher Lu, Tzuchun Tsai, Sielin Choo, Shuyu Yeh, Renbing Tang, Anhang Yang, Hsinyu Lee and Jenkann Lu
- 作者服務機構: Department of Pediatrics and Pathology, Taipei Veterans General Hospital, Taipei, Taiwan, R.O.C.
- 中文摘要: --
- 英文摘要:
Background: The tbx5 mutation in human causes Holt-Oram syndrome, an
autosomal dominant condition characterized by a familial history of congenital heart
defects and preaxial radial upper-limb defects. We report aberrant apoptosis and
dormant cell growth over head, heart, trunk, fin, and tail of zebrafish embryos with
tbx5 deficiency correspond to the dysmorphogenesis of tbx5 morphants.
Methods: Wild-type zebrafish embryos at the 1-cell stage were injected with 4.3 nl of
19.4 ng of tbx5 morpholino or mismatch-tbx5-MO respectively in tbx5 morphants and
mismatched control group. Semi-quantitative RT-PCR was used to for expression
analysis of apoptosis and cell cycle-related genes. TUNEL and immunohistochemical
assay showed the apoptosis spots within the local tissues. Ultra-structure of cardiac
myocardium was examined by transmission electron microscope.
Results: Apoptosis-related genes (bad, bax, and bcl2), and cell cycle-related genes
(cdk2, pcna, p27, and p57) showed remarkable increases in transcriptional level by
RT-PCR. Using a TUNEL and immnuohistochemical assay, apoptosis was observed in
the organs including the head, heart, pectoral fins, trunk, and tail of tbx5 knockdown
embryos. Under transmission electron microscopic examination, mitochondria in
cardiomyocytes became swollen and the myocardium was largely disorganized with a
disarrayed appearance, compatible with reduced enhancement of myosin in the
cardiac wall. The ATP level was reduced, and the ADP/ATP ratio as an apoptotic
index significantly increased in the tbx5 deficient embryos.
Conclusion: Our study highlighted that tbx5 deficiency evoked apoptosis, distributed
on multiple organs corresponding to dysmorphogenesis with the shortage of
promising maturation, in tbx5 knockdown zebrafish embryos. We hypothesized that
mesenchymal cell apoptosis associated with altered TBX5 level may subsequently
interfered with organogenesis and contributed to dysmorphogenesis in tbx5 deficiency zebrafish embryos.
- 中文關鍵字: --
- 英文關鍵字: zebrafish, mitochondria, apoptosis, tbx5, Holt-Oram syndrome, cell cycle