Apical ectodermal ridge regulates three principal axes of the developing limb / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Understanding limb development not only gives insights into the outgrowth and differentiation of the limb, but also has clinical relevance. Limb development begins with two paired limb buds (forelimb and hindlimb buds), which are initially undifferentiated mesenchymal cells tipped with a thickening of the ectoderm, termed the apical ectodermal ridge (AER). As a transitional embryonic structure, the AER undergoes four stages and contributes to multiple axes of limb development through the coordination of signalling centres, feedback loops, and other cell activities by secretory signalling and the activation of gene expression. Within the scope of proximodistal patterning, it is understood that while fibroblast growth factors (FGFs) function sequentially over time as primary components of the AER signalling process, there is still no consensus on models that would explain proximodistal patterning itself. In anteroposterior patterning, the AER has a dual-direction regulation by which it promotes the sonic hedgehog (Shh) gene expression in the zone of polarizing activity (ZPA) for proliferation, and inhibits Shh expression in the anterior mesenchyme. In dorsoventral patterning, the AER activates Engrailed-1 (En1) expression, and thus represses Wnt family member 7a (Wnt7a) expression in the ventral ectoderm by the expression of Fgfs, Sp6/8, and bone morphogenetic protein (Bmp) genes. The AER also plays a vital role in shaping the individual digits, since levels of Fgf4/8 and Bmps expressed in the AER affect digit patterning by controlling apoptosis. In summary, the knowledge of crosstalk within AER among the three main axes is essential to understand limb growth and pattern formation, as the development of its areas proceeds simultaneously.

Apical ectodermal ridge regulates three principal axes of the developing limb / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Understanding limb development not only gives insights into the outgrowth and differentiation of the limb, but also has clinical relevance. Limb development begins with two paired limb buds (forelimb and hindlimb buds), which are initially undifferentiated mesenchymal cells tipped with a thickening of the ectoderm, termed the apical ectodermal ridge (AER). As a transitional embryonic structure, the AER undergoes four stages and contributes to multiple axes of limb development through the coordination of signalling centres, feedback loops, and other cell activities by secretory signalling and the activation of gene expression. Within the scope of proximodistal patterning, it is understood that while fibroblast growth factors (FGFs) function sequentially over time as primary components of the AER signalling process, there is still no consensus on models that would explain proximodistal patterning itself. In anteroposterior patterning, the AER has a dual-direction regulation by which it promotes the sonic hedgehog (Shh) gene expression in the zone of polarizing activity (ZPA) for proliferation, and inhibits Shh expression in the anterior mesenchyme. In dorsoventral patterning, the AER activates Engrailed-1 (En1) expression, and thus represses Wnt family member 7a (Wnt7a) expression in the ventral ectoderm by the expression of Fgfs, Sp6/8, and bone morphogenetic protein (Bmp) genes. The AER also plays a vital role in shaping the individual digits, since levels of Fgf4/8 and Bmps expressed in the AER affect digit patterning by controlling apoptosis. In summary, the knowledge of crosstalk within AER among the three main axes is essential to understand limb growth and pattern formation, as the development of its areas proceeds simultaneously.

The ORF 113 of Heliocoverpa armigera Single Nucleopolyhedrovirus Encodes a Functional Fibroblast Growth Factor / 中国病毒学·英文版

Fibroblast growth factor (FGF) is a key regulator of developmental processes. A FGF homolog (vFGF) is found in all lepidopteran baculoviruses. Autographa californica nucleopolyhedrovirus (AcMNPV) and Bombyx mori NPV (BmNPV) vFGFs are chemotactic factors. Here we analyzed the vfgf of Helicoverpa armigera NPV (HearNPV), a group Ⅱ NPV. The HearNPV vfgftranscripts were detected from 18 to 96 h post-infection (hpi) of Hz-AMI cells with HearNPV and encoded a 36 kDa protein, which was secreted into the culture medium. HearNPV vFGF had strong affinity to heparin, a property important for FGF signaling via an FGF receptor. Unlike its AcMNPV homolog, HearNPV vFGF specially chemoattracted Hz-AM 1, but not other insect cells such as Sf9 and Se-UCR and not the mammalian cells 293 and HepG2. HearNPV vFGF is also associated with the envelope of BV but is absent in occlusion-derived virus, which coordinated to the chemotatic activity analysis.

Bladder Regeneration by Small Intestinal Submucosa with Release of Exogenous Growth Factors / 中国康复理论与实践

@#ObjectiveTo explore the release of exogenous growth factors from small intestinal submucosa (SIS) in bladder regeneration. MethodsThe release of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) from SIS in vitro were evaluated by ELISA and MTT method. The defected bladder walls of rats in experimental group were repaired with porcine small intestinal submuscosa. Partial bladder mucosa and smooth muscle of the rats in control groups were destroyed. At regular intervals, the VEGF and bFGF expression were observed by histological and immunohistochemical methods. ResultsThe concentration of bFGF and VEGF released in vitro from SIS in PBS solution were (121.8±2.683) ng/L and (93.8±3.033) ng/L respectively, and showed proliferation of vascular endothelial cell. In the SIS framework, the capillary and smooth muscle were observed followed histological evaluation. The weak expression of VEGF and bFGF in both experimental and control groups were found in the first week. Since the second week the VEGF and bFGF expression in experimental group began to increase with a peak in the 6th week, and began to decrease after 8 weeks. In the control group, the weak VEGF and bFGF expression were shown during the observation. ConclusionSIS functions as a carrier for exogenous growth factors release in rat bladder regeneration.

Bladder Regeneration by Small Intestinal Submucosa with Release of Exogenous Growth Factors / 中国康复理论与实践

@#ObjectiveTo explore the release of exogenous growth factors from small intestinal submucosa (SIS) in bladder regeneration. MethodsThe release of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) from SIS in vitro were evaluated by ELISA and MTT method. The defected bladder walls of rats in experimental group were repaired with porcine small intestinal submuscosa. Partial bladder mucosa and smooth muscle of the rats in control groups were destroyed. At regular intervals, the VEGF and bFGF expression were observed by histological and immunohistochemical methods. ResultsThe concentration of bFGF and VEGF released in vitro from SIS in PBS solution were (121.8±2.683) ng/L and (93.8±3.033) ng/L respectively, and showed proliferation of vascular endothelial cell. In the SIS framework, the capillary and smooth muscle were observed followed histological evaluation. The weak expression of VEGF and bFGF in both experimental and control groups were found in the first week. Since the second week the VEGF and bFGF expression in experimental group began to increase with a peak in the 6th week, and began to decrease after 8 weeks. In the control group, the weak VEGF and bFGF expression were shown during the observation. ConclusionSIS functions as a carrier for exogenous growth factors release in rat bladder regeneration.