Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.5.1.3 (dihydrofolate reductase)
 5,819 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The gene therapy approach presented in this protocol employs a polymer encapsulated, xenogenic, transfected cell line to release human ciliary neurotrophic factor (hCNTF) for the treatment of Amyotrophic Lateral Sclerosis (ALS). A tethered device, containing around 10(6) genetically modified cells surrounded by a semipermeable membrane, is implanted intrathecally; it provides for slow continuous release of hCNTF at a rate of 0.25 to 1.0 micrograms/24 hours. The semipermeable membrane prevents immunologic rejection of the cells and interposes a physical, virally impermeable barrier between cells and host. Moreover, the device and the cells it contains may be retrieved in the event of side effects. A vector containing the human CNTF gene was transfected into a line of baby hamster kidney cells (BHK) with calcium phosphate using a dihydrofolate reductase-based selection vector with a SV40 promoter and contains a HSV-tk killer gene. hCNTF is a potent neurotrophic factor which may have utility for the treatment of ALS. Systemic delivery of hCNTF in humans has been frustrated by peripheral side effects, the molecule's short half life, and its inability to cross the blood-brain barrier. The gene therapy approach described in this protocol is expected to mitigate such difficulties by local intrathecal delivery of a known quantity of continuously-synthesized hCNTF from a retrievable implant.
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PMID:Gene therapy for amyotrophic lateral sclerosis (ALS) using a polymer encapsulated xenogenic cell line engineered to secrete hCNTF. 886 Aug 37

Regulating transgene expression in vivo by delivering oral drugs has been a long-time goal for the gene therapy field. A novel gene regulating system based on targeted proteasomal degradation has been recently developed. The system is based on a destabilizing domain (DD) of the Escherichia coli dihydrofolate reductase (DHFR) that directs fused proteins to proteasomal destruction. Creating YFP proteins fused to destabilizing domains enabled TMP based induction of YFP expression in the brain, whereas omission of TMP resulted in loss of YFP expression. Moreover, induction of YFP expression was dose dependent and at higher TMP dosages, induced YFP reached levels comparable to expression of unregulated transgene., Transgene expression could be reversibly regulated using the DD system. Importantly, no adverse effects of TMP treatment or expression of DD-fusion proteins in the brain were observed. To show proof of concept that destabilizing domains derived from DHFR could be used with a biologically active molecule, DD were fused to GDNF, which is a potent neurotrophic factor of dopamine neurons. N-terminal placement of the DD resulted in TMP-regulated release of biologically active GDNF. Our findings suggest that TMP-regulated destabilizing domains can afford transgene regulation in the brain. The fact that GDNF could be regulated is very promising for developing future gene therapies (e.g. for Parkinson's disease) and should be further investigated.
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PMID:Destabilizing domains mediate reversible transgene expression in the brain. 2302 56