Of Mice And Me

As many of my readers know, about two years ago I came across a study investigating a novel molecule for the treatment of Alzheimer's. The molecule, J147, is a synthetic derivative of curcumin. Curcumin and other similar molecules have long been under study for neurodegenerative diseases. Unfortunately curcuminoids have rather poor bioavailability, meaning they are quickly excreted from the body and require high amounts to have a therapeutic value. Like curcumin, J147 is "orally available" (meaning it is introduced to the body by eating it) but is more than 100X as potent. This means a much smaller quantity is necessary for therapeutic effect. So far, we haven't found a toxic dose of J147. Work on toxicity is ongoing.

In the Alzheimer's study J147 had remarkable results in that model. The pathways acted upon were quite relevant to ALS. These include potent antioxidant effects, significant reduction of microglia activation and migration, and reduction of heat-shock protein expression which indicates a shift back toward cellular homeostasis. More recent data (unpublished) indicates an effect in reducing astrocyte activation, which is sufficient to rapidly kill even healthy motor neurons.

Unfortunately, because J147 is pleiotropic, pharmaceutical companies weren't interested. The current research paradigm is to focus on single molecular targets. For diseases with a single mechanisms, that's a fine method of attack. But ALS has quite a few things going on simultaneously. All prior single-target treatments have failed and the current growing opinion is that successful treatment would require a cocktail of drugs. Better to have a single pleiotropic substance than a mixture of chemicals with uncertain interactions.

In April, 2013, I created SciOpen Research Group in order to have an entity capable of negotiating research and licensing of novel molecules with the promise of treatment of ALS. J147 is our first project. In the early summer of 2013, SRG applied to Prize4Life for access to their colony of G93A transgenic research mice at Jackson Laboratories. Our research proposal for J147 was accepted and we were given granted sufficient animal numbers to properly conduct our study. We received the mice and started the experiment at the end of January.

We are very excited to have commenced our first research program and demonstrate that guerrilla biotechs can perform quality science. To that end, we created a crowdfunding campaign on Indiegogo to obtain funding for the next step of the experiment - microscopic tissue examination. This will tell us exactly what J147 did to help the motor neurons in the mice.

Please donate if you can. All donations are tax-deductible. If you cannot donate please spread word about SRG and our need for funding this new and exciting research.

Carpe Fragments

In the developing embryo, motor neurons develop and nearly half preferentially die prior to birth (Henderson, et al., 1997, "Hepatocyte growth factor (HGF/SF) is a muscle-derived survival factor for a subpopulation of embryonic motoneurons"). As shown in Forger, et al., 2001 ("Blockade of Endogenous Neurotrophic Factors Prevents the Androgenic Rescue of Rat Spinal Motoneurons"), loss of muscular targets also leads to post-natal motor neuron degeneration. Post-natal mice engineered to have degenerated muscle spindles exhibit ataxia and resting tremors, indicating a decrease in proprioception due to loss of sensory-motor synapses (Frank, et al., 2002, "Muscle Spindle-Derived Neurotrophin 3 Regulates Synaptic Connectivity between Muscle Sensory and Motor Neurons").

One interesting factor seems to suggest a link with testosterone in preserving motor neurons, which could be a possible explanation for the statistically higher numbers of men affected in middle-age or above, and that of women in post-menopause, when hormone levels experience radical shift. Indeed, Cilliary Neurotrophic Factor, a potent motor neuron trophic factor, is regulated by gonadal hormones (Forger, et al., 1998, "Ciliary Neurotrophic Factor Receptor in Spinal Motoneurons is Regulated by Gonadal Hormones").

Leaving aside the question of hormone levels, there is much evidence that muscle-derived neurotrophic factors are necessary for the health and survival of the motor neurons. One in particular, Motoneuronotrophic Factor 1 (MNTF1), appears essential to this critical process. Experiments in Wobbler mice show that motor neuron disease increases as MNTF1 levels decrease (http://www.ncbi.nlm.nih.gov/pubmed/10453487). MNTF1 was first described in the early 90s, and the human form was successfully cloned as an artificial protein. Various fragments were extracted and shown to have neurotrophic effect.

Two overlapping domains of a 33 amino acid fragment of MNTF1, dubbed the Fred and Wilma domains, are sufficient to stimulate motor neuroprotection in a manner similar to the whole 33 amino acid MNTF1 fragment. The Fred domain is sufficient to direct selective reinnervation of muscle targets by motor neurons in vivo in a manner similar to the 33 amino acid MNTF1 fragment. A recombinant protein containing the Fred domain maintained motoneuron viability, increased neurite outgrowth, reduced motoneuron cell death/apoptosis and supported the growth and spreading of motoneurons into giant, active neurons with extended growth cone-containing axons.

For those curious about the amino acids in each domain, please refer to the image below:

From the above it is quite possible that at least some forms of ALS are caused by a sort of a muscular dystrophy (not to be confused with the distinct condition by that name). It therefore stands to reason that there is reason for hope that some will benefit. The standard caveat of basic and preclinical research often not translating to human trials obviously applies. However, we are entering an exciting time where extremely potent shots are being taken at more fundamental aspects of ALS. One or a combination seem likely to have the effect we have been waiting for.

Old Tricks

Something very intriguing came in over the weekend from PLoSONE. It was a study comparing neuromuscular junctions between age and ALS. It turns out that the same muscles susceptible to denervation in ALS are likewise susceptible to denervation with age. Autonomic muscles (those that act without your conscious input) and muscles innervated directly from the brain (eg your eyes and certain facial muscles) are extraordinarily resistant to age- and ALS-related denervation. Something that struck me was the finding that TDP43 was mislocalized in aged motor neurons very similarly to ALS motor neurons. TDP43 is normally found in the nucleus but in ALS it is found in the cytoplasm where it is cleaved by caspases and a 25 kilodalton fragment aggregates in a form that apparently gains a toxic function.

TDP43 mislocalization has also been found by the symptomatic phase in the SOD1 mouse model (although earlier and more recent reports are somewhat contradictory on this point). Another protein found upregulated in the SOD1 mouse is CRMP4a, a subprotien of the CRMP family. CRMP4 is normally involved in learning, neurite outgrowth, and building functional circuitry within the brain. However, the Duplan, et al., 2010 study referenced above found upregulation or overexpression of CRMP4a is deadly specific to motor neurons. In the subject study of this post, Valdez, et al., 2012, CRMP4a was also found upregulated in the same types of motor neurons of normally-aged mice as those which degenerate in ALS mice. CRMPs are known to change due to age.

Inflammation is present in all neurodegenerative diseases. One of the primary drivers of ALS is thought to be neuroinflammation. Multiple animal models of ALS, including data in humans, show neuroinflammation. As the subject study shows, TDP43 and CRMP4 is upregulated in both aging and ALS. Taking one step further, aging and ALS have another thing in common: Inflammation.