Preparation and a structure-function analysis of human ciliary neurotrophic factor

Recombinant ciliary neurotrophic factor promotes nerve regeneration and induces gene expression in silicon tube-bridged transected sciatic nerves in adult rats

Sciatic nerves in adult male rats were transected and reunited via a silicone chamber. This was followed by a focal injection of recombinant ciliary neurotrophic factor (CNTF). To evaluate the effect of this therapeutic approach and to explore its possible mechanisms, nerve regeneration was traced by horseradish peroxidase retrograde labeling. Functional recovery was evaluated by functional assessment of the hind feet and the expression of a number of proteins was detected using immunohistochemistry. The results showed that a single administration of CNTF could promote regeneration of motor axons, with improved functional recovery in adult rats. Growth associated protein (GAP)-43, S100, CD68 and major histocompatibility complex class II immunoreactivity in the regenerative and distal nerves suggested that CNTF could promote axon regeneration, Schwann cell migration, monocyte infiltration and activation. CNTF might also indirectly promote axonal regeneration by further activating the JAK-STAT3 pathway and subsequently upregulating phosphotyrosine, GAP-43 and S100 expression to enhance proliferation, growth and migration of Schwann cells. CNTF has suggested important targets for pharmacological intervention in peripheral nerve disease and injury.

Ciliary neurotrophic factor receptor alpha subunit-modulated multiple downstream signaling pathways in hepatic cancer cell lines and their biological implications

Ciliary neurotrophic factor (CNTF) plays important roles in a variety of tissues including neural and non-neural systems, but the function of CNTF and its receptor (CNTFR) in liver remains unclear. In this study, we demonstrate that CNTFRalpha is expressed heterogeneously in normal human liver and hepatocellular carcinoma (HCC) specimens but not in hepatoblastoma specimens. We choose the CNTFRalpha(+)/CNTFRalpha(-) (CNTFRalpha positive/ CNTFRalpha negative) cell models of hepatic origin to study multiple downstream pathways of CNTFRalpha. We show that the presence of CNTFRalpha determines the temporal activation patterns of downstream signaling molecules and serves as a key modulator in regulating PI3K and AMP-activated protein kinase (AMPK) dynamically under CNTF stimulation, thus resulting in the increase of glucose uptake and translocation of glucose transporter 4 (GLUT4). Furthermore, CNTF-induced mitogen-activated protein kinase (MAPK) activation suppresses AMPK activity in the early phase of CNTF stimulation. Moreover, the protective role of CNTF against cell-cycle arrest is dependent on the presence of CNTFRalpha and is modulated by the glucose concentration of the culture medium.

CONCLUSION

Our results demonstrate the importance of CNTFRalpha-mediated downstream signaling pathways and their functional implications in hepatic cancer cells, thus highlighting a better understanding of the biological roles of CNTFRalpha in human liver abnormalities, including metabolic diseases and hepatocarcinogenesis.

The effects of ciliary neurotrophic factor on neurological function and glial activity following contusive spinal cord injury in the rats

Ciliary neurotrophic factor (CNTF) has been implicated in the pathophysiology of injury to the central nervous system. The rapid increase in CNTF production following spinal cord injury (SCI) in rats is thought to serve a role in the neuronal survival and functional recovery. In this study, 40 SD rats were divided into four groups: sham-operated group, saline-treated group, 5- and 10-microg CNTF group. Saline and CNTF were given through lumbar intrathecal catheter for 10 days after T10 segment of spinal cord were injured by modified Allen contusion method. Animals were behaviorally tested for 6 weeks using the Basso, Beattie, Bresnahan locomotor rating scale and inclined plane test. At the end of 6 week, rubrospinal neurons of five rats in each group were labeled by retrograde transport of the horseradish peroxidase (HRP) from the lesion site, and then the labeled red nucleus neuron (RN) numbers were counted. Additional rats were histologically assessed for tissue sparing and neuronal loss and reactive gliosis at the injury site and adjacent areas. Rats treated with CNTF regained greater improvements in hindlimb function than controls. The amount of spared tissue was significantly higher in CNTF-treated animals than in controls. After CNTF treatment, the number of HRP-labeled RN neurons were significantly increased. Astrocytes and microglia reactivity was more pronounced in CNTF-treated animals than in controls. These results indicate that intrathecal infusion of exogenous CNTF following SCI may significantly reduce tissue damage and protect the rubrospinal descending tracks and enhances functional recovery, and may also induce more gliosis.