CNTF Human, His
Description
Introduction to CNTF Human, His
CNTF Human, His refers to a recombinant human ciliary neurotrophic factor (CNTF) protein fused with a polyhistidine (His) tag. This tag facilitates purification via affinity chromatography while retaining the protein's biological activity . CNTF is a neurotrophic cytokine critical for neuronal survival, differentiation, and regeneration, particularly in motor neurons and oligodendrocytes . The His-tagged variant is widely used in research and therapeutic development due to its stability and ease of production in Escherichia coli .
Biochemical Properties
Biological Activity
CNTF Human, His exhibits potent neurotrophic effects:
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ED₅₀: ≤1 µg/mL in TF-1 human erythroleukemic cell proliferation assays .
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Mechanism: Activates the JAK/STAT pathway via a tripartite receptor complex (CNTFRα, gp130, LIFRβ) .
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Key Functions:
Neurodegenerative Diseases
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Amyotrophic Lateral Sclerosis (ALS): Clinical trials showed CNTF reduced motor neuron degeneration but faced challenges due to antibody development and limited efficacy .
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Retinitis Pigmentosa: Encapsulated CNTF implants (NT-501) slowed photoreceptor degeneration in Phase I trials .
Metabolic Disorders
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Obesity: CNTF administration caused significant weight loss in humans by mimicking leptin signaling . Plasma CNTF levels correlate with BMI and insulin resistance .
Clinical and Preclinical Findings
Research Limitations and Future Directions
While CNTF Human, His shows promise, challenges include:
Product Specs
Q&A
Here’s a structured collection of FAQs tailored for academic researchers studying recombinant human CNTF with His-tag (CNTF Human, His), based on scientific literature and experimental data:
What structural features classify CNTF within the IL-6 cytokine family?
CNTF shares a four α-helix bundle tertiary structure with IL-6 family members (IL-6, LIF, OSM) but lacks a secretory signal peptide . Its receptor complex includes:
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gp130 and LIFRβ: Shared signal-transducing subunits
Methodological note: Confirm structural homology using SDS-PAGE (26 kDa band under reducing conditions) or X-ray crystallography .
How does CNTF promote neuronal survival in experimental models?
CNTF activates the JAK/STAT pathway via receptor phosphorylation, supporting:
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Motor neuron survival: Prevents axotomy-induced degeneration (ED₅₀: 0.03–0.18 μg/mL in TF-1 cell assays)
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Glial differentiation: Induces type 2 astrocyte formation
Experimental design: Use primary neuron cultures with CNTF knockout controls and measure apoptosis via TUNEL assays .
What are standard bioactivity validation methods for recombinant CNTF?
How to address contradictory findings on CNTF G>A null mutation and obesity?
Key studies:
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O’Dell et al. (2002): A/A genotype linked to +10 kg weight in males (n=575)
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Hoffmann et al. (2004): No association in U.S. cohorts (n=755)
Resolution strategies:
What challenges arise in stabilizing recombinant CNTF for in vivo delivery?
Instability factors:
Why did CNTF fail in Huntington’s disease clinical trials despite preclinical success?
Preclinical efficacy:
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Delivery issues: Intraventricular capsules showed poor CNS penetration
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Target engagement: No improvement in UHDRS scores despite electrophysiological signals
Recommendation: Pair CNTF with blood-brain barrier penetration enhancers.
How to resolve low CNTF bioactivity in transfected cell lines?
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Check post-translational modifications: CNTF lacks glycosylation sites
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Validate secretion: Use Western blot with anti-His probes (20-amino-acid tag)
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Optimize transfection: Lentiviral vectors > plasmid transfection in BHK cells
What controls are critical for CNTF pathway analysis?
Product Science Overview
Ciliary Neurotrophic Factor (CNTF) is a polypeptide hormone and neurotrophic factor primarily involved in the nervous system. It is encoded by the CNTF gene in humans and plays a crucial role in promoting neurotransmitter synthesis and neurite outgrowth in specific neuronal populations . The recombinant version of human CNTF, often tagged with a His (histidine) tag for purification purposes, is widely used in research and therapeutic applications.
CNTF is a protein with a molecular weight of approximately 23 kDa . It exerts its effects by binding to a heterotrimeric receptor complex composed of the CNTF receptor alpha (CNTFRα), glycoprotein 130 (gp130), and leukemia inhibitory factor receptor beta (LIFRβ) . This binding initiates a cascade of intracellular signaling pathways that promote cell survival, differentiation, and growth.
CNTF is a potent survival factor for various neuronal cell types, including motor neurons and oligodendrocytes . It has been shown to prevent the degeneration of motor axons following axotomy (nerve injury) and may reduce tissue destruction during inflammatory attacks . Additionally, CNTF is involved in the regulation of gene expression, axon regeneration, and the activation of astrocytes .
Recombinant human CNTF (rhCNTF) is produced using recombinant DNA technology, where the CNTF gene is cloned and expressed in a suitable host system, such as Escherichia coli or mammalian cells . The His tag, a sequence of histidine residues, is added to the protein to facilitate purification using affinity chromatography. This tag allows for efficient isolation of the recombinant protein from the host cell lysate.
Recombinant CNTF has several applications in research and medicine:
- Neuroprotection: CNTF is used in studies investigating neuroprotective strategies for neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS) .
- Cell Culture: CNTF is often used as a supplement in cell culture media to support the growth and differentiation of neuronal cells .
- Therapeutic Potential: CNTF has been explored as a potential therapeutic agent for various neurological conditions due to its ability to promote neuronal survival and regeneration .
