Piggybacking on the Cholera Toxin: Identification of a CTB-Binding Protein as an Approach for Targeted Delivery of Proteins to Motor Neurons

Author(s):  
Matthew R. Balmforth ◽  
Jessica Haigh ◽  
Vajinder Kumar ◽  
Wenyue Dai ◽  
Christian Tiede ◽  
...  
2020 ◽  
Author(s):  
Matthew R. Balmforth ◽  
Jessica Haigh ◽  
Christian Tiede ◽  
Darren C. Tomlinson ◽  
Jim Deuchars ◽  
...  

ABSTRACTA significant unmet need exists for the delivery of biologic drugs such as polypeptides or nucleic acids, to the central nervous system (CNS) for the treatment and understanding of neurodegenerative diseases. Naturally occurring toxoids have been considered as tools to meet this need. However, due to the complexity of tethering macromolecular drugs to toxins, and the inherent dangers of working with large quantities of recombinant toxin, no such route has been successfully exploited. Developing a method where toxoid and drug can be assembled immediately prior to in vivo administration has the potential to circumvent some of these issues. Using a phage-display screen, we identified two antibody mimetics, Anti-Cholera Toxoid Affimer (ACTA) -A2 and ACTA-C6 that non-covalently associate with the non-binding face of the cholera toxin B-subunit. In a first step toward the development of a non-viral motor neuron drug-delivery vehicle, we show that Affimers can be selectively delivered to motor neurons in vivo.


2015 ◽  
Vol 35 (14) ◽  
pp. 2385-2399 ◽  
Author(s):  
Nadine Bakkar ◽  
Arianna Kousari ◽  
Tina Kovalik ◽  
Yang Li ◽  
Robert Bowser

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the selective loss of motor neurons. Various factors contribute to the disease, including RNA binding protein dysregulation and oxidative stress, but their exact role in pathogenic mechanisms remains unclear. We have recently linked another RNA binding protein, RBM45, to ALS via increased levels of protein in the cerebrospinal fluid of ALS patients and its localization to cytoplasmic inclusions in ALS motor neurons. Here we show RBM45 nuclear exit in ALS spinal cord motor neurons compared to controls, a phenotype recapitulatedin vitroin motor neurons treated with oxidative stressors. We find that RBM45 binds and stabilizes KEAP1, the inhibitor of the antioxidant response transcription factor NRF2. ALS lumbar spinal cord lysates similarly show increased cytoplasmic binding of KEAP1 and RBM45. Binding of RBM45 to KEAP1 impedes the protective antioxidant response, thus contributing to oxidative stress-induced cellular toxicity. Our findings thus describe a novel link between a mislocalized RNA binding protein implicated in ALS (RBM45) and dysregulation of the neuroprotective antioxidant response seen in the disease.


Development ◽  
1990 ◽  
Vol 109 (1) ◽  
pp. 75-80 ◽  
Author(s):  
M. Maden ◽  
D.E. Ong ◽  
F. Chytil

We have analysed the distribution of cellular retinol-binding protein (CRBP) and cellular retinoic acid-binding protein (CRABP) in the day 8.5-day 12 mouse and rat embryo. CRBP is localised in the heart, gut epithelium, notochord, otic vesicle, sympathetic ganglia, lamina terminalis of the brain, and, most strikingly, in a ventral stripe across the developing neural tube in the future motor neuron region. This immunoreactivity remains in motor neurons and, at later stages, motor axons are labelled in contrast to unlabelled sensory axons. CRABP is localised to the neural crest cells, which are particularly noticeable streaming into the branchial arches. At later stages, neural crest derivatives such as Schwann cells, cells in the gut wall and sympathetic ganglia are immunoreactive. An additional area of CRABP-positive cells are neuroblasts in the mantle layer of the neural tube, which subsequently appear to be the axons and cell bodies of the commissural system. Since retinol and retinoic acid are the endogenous ligands for these binding proteins, we propose that retinoids may play a role in the development and differentiation of the mammalian nervous system and may interact with certain homoeobox genes whose transcripts have also been localised within the nervous system.


2015 ◽  
Vol 112 (12) ◽  
pp. 2611-2617 ◽  
Author(s):  
Ana M. Chamoun-Emanuelli ◽  
Gus Wright ◽  
Smith Roger ◽  
Robert C. Münch ◽  
Christian J. Buchholz ◽  
...  

2016 ◽  
Vol 113 (31) ◽  
pp. E4494-E4503 ◽  
Author(s):  
Douglas M. Anderson ◽  
Jessica Cannavino ◽  
Hui Li ◽  
Kelly M. Anderson ◽  
Benjamin R. Nelson ◽  
...  

Innervation of skeletal muscle by motor neurons occurs through the neuromuscular junction, a cholinergic synapse essential for normal muscle growth and function. Defects in nerve–muscle signaling cause a variety of neuromuscular disorders with features of ataxia, paralysis, skeletal muscle wasting, and degeneration. Here we show that the nuclear zinc finger protein ZFP106 is highly enriched in skeletal muscle and is required for postnatal maintenance of myofiber innervation by motor neurons. Genetic disruption of Zfp106 in mice results in progressive ataxia and hindlimb paralysis associated with motor neuron degeneration, severe muscle wasting, and premature death by 6 mo of age. We show that ZFP106 is an RNA-binding protein that associates with the core splicing factor RNA binding motif protein 39 (RBM39) and localizes to nuclear speckles adjacent to spliceosomes. Upon inhibition of pre-mRNA synthesis, ZFP106 translocates with other splicing factors to the nucleolus. Muscle and spinal cord of Zfp106 knockout mice displayed a gene expression signature of neuromuscular degeneration. Strikingly, altered splicing of the Nogo (Rtn4) gene locus in skeletal muscle of Zfp106 knockout mice resulted in ectopic expression of NOGO-A, the neurite outgrowth factor that inhibits nerve regeneration and destabilizes neuromuscular junctions. These findings reveal a central role for Zfp106 in the maintenance of nerve–muscle signaling, and highlight the involvement of aberrant RNA processing in neuromuscular disease pathogenesis.


FEBS Letters ◽  
1998 ◽  
Vol 431 (2) ◽  
pp. 231-235 ◽  
Author(s):  
Kaoru Kubokawa ◽  
Tomoyuki Miyashita ◽  
Yoshihiro Kubo

Cell ◽  
1987 ◽  
Vol 48 (2) ◽  
pp. 271-279 ◽  
Author(s):  
Virginia L. Miller ◽  
Ronald K. Taylor ◽  
John J. Mekalanos

Sign in / Sign up

Export Citation Format

Share Document