From the University of Missouri News Bureau:

Molecular Therapy for Spinal Muscular Atrophy Closer to Clinical Use
MU researcher improves efficiency of trans-splicing therapy

Dec. 15, 2008
Story Contact: Kelsey Jackson, (573) 882-8353, JacksonKN@missouri.edu

COLUMBIA, Mo. - Spinal muscular atrophy, a neurodegenerative disorder that causes the weakening of muscles, is the leading cause of infant death and occurs in 1 in 6,000 live births. While trans-splicing (a form of molecular therapy) has had impressive results as a treatment for spinal muscular atrophy in cell-based models of disease, scientists have been unable to translate the therapy to the human body. A University of Missouri researcher has developed a strategy that will enhance trans-splicing activity and bring it closer to being used in the clinical setting.

Spinal muscular atrophy is caused by the loss of survival motor neuron-1(SMN1). In humans, a nearly identical copy gene is present called SMN2. Because of a single molecular difference, SMN2 alone cannot compensate for the loss of SMN1, but it can be used as a primary target for therapeutics, including trans-splicing. Trans-splicing therapy relies on splicing, or uniting, of mutant RNA and therapeutic RNA in order to correct RNA sequence.

To improve efficiency, the researchers developed a trans-splicing system that uses a strand of RNA that can bind to a gene and inactivate it. Turning the gene “off” reduces competition at splice sites and improves the likelihood of achieving the desired results.

“The key to introducing trans-splicing in clinical settings is developing efficient trans-splicing systems,” said Chris Lorson, investigator in the Christopher S. Bond Life Sciences Center; associate professor of veterinary pathobiology in the MU College Veterinary Medicine; and scientific director for Fight SMA, a private spinal muscular atrophy research foundation in Richmond, Va. “We have found that reducing the competition between the splice sites enhances the efficiency of trans-splicing. This strategy provides insight into the trans-splicing mechanism and significantly improves trans-splicing activity in a mouse model of spinal muscular atrophy.”

The study, “Development of a Single Vector System that Enchances Trans-splicing of SMN2 Transcripts,” was published in PLoS ONE and was co-authored by Lorson; MU researchers Tristan H. Coady, Travis D. Baughan and Monir Shababi; and Genzyme Corporation neuroscience researcher Marco A. Passini.

Click here for the original news release.

This work was funded by grants from the MDA, FightSMA, and the National Institutes of Health. To read the published article mentioned in the news release, click here.

A study published online October 8th by the monthly journal ACS Chemical Biology reports that scientists have made “a key advance toward developing the first effective drug treatment for spinal muscular atrophy (SMA).”

SMA is an autosomal recessive neurodegenerative disease characterized by the dramatic loss of spinal motor neurons, resulting in muscle weakness, atrophy, and in the worst cases, the loss of ability to swallow and breathe. SMA occurs when a vital gene, the “survivor motor neuron” gene or “SMN” is deleted or mutated, preventing the creation of a protein necessary for muscle strength. Even though the key SMN gene is deleted, there is a second “copy” gene (the “SMN2″ gene) that continues to produce limited quantities of the SMN protein.

After screening hundreds of thousands of compounds, researchers are looking at C5-quinazolines as a potential method of increasing the SMN2 activity and thus the protein SMA patients lack. According to Jill Jarecki, Ph.D., Research Director at Families of SMA, “the results outlined in the paper and carried out in collaboration with Families of SMA, deCODE chemistry & biostructures, Invitrogen Corporation, and Rutgers University represent a new understanding of the physiological mechanisms that can increase SMN expression and will allow us to move forward in advancing potential treatments for it.”

To read more, click here.

 Fighting Back Episode 9 [11:45m]: Download

This episode is a bit of a departure for the Fighting Back Podcast. We usually interview people and families fighting against serious diseases. We’ve spoken to a woman trying to raise the profile of SMA through a one-woman stage show, a mother starting a foundation to raise money for myotonic muscular dystrophy, a mother who launched what became a national organization to fight for orphan disease, and many more. This episode is a bit different, however. This time we’re talking to a man who is fighting diseases directly.

Dr. Alex MacKenzie is a pediatrician, spinal muscular atrophy researcher, and director of the Research Institute at Children’s Hospital of Eastern Ontario. In episode 9 of Fighting Back, host Steve Mullen talks with Dr. MacKenzie about SMA research and how it’s benefiting many other diseases.

Links mentioned in this episode:
Matrix of SMN Mutations

To hear Episode 9 of Fighting Back, you have several options. You can listen using the Flash mp3 player above. Or, if you’re a fan of podcast RSS feeds, you can use the Fighting Back Podcast Feed in your favorite feed reader. If you’re an iTunes user you can subscribe and download via our iTunes store. Finally, you can, of course, download this episode using the link above.

If you have feedback, a comment or question, or are interested in having Fighting Back tell your story, please contact us via the Fight SMA contact page or leave us a voice mail message at our new voicemail hotline number – 206-222-1903. You can also leave a message in the form of a comment on this blog as well.

Atlanta-based biopharmaceutical company Tikvah Therapeutics announced this week that it has received orphan drug status from the U.S. Food and Drug Administration for use of sodium phenylbutyrate as a treatment for spinal muscular atrophy (SMA).  The orphan drug status gives Tikvah seven years of market exclusivity for use of phenylbutyrate for SMA treatment.

Findings from in vitro studies by Tikvah, as well as pilot clinical work, suggest that phenylbutyrate treatment in SMA patients may improve motor function.

Tikvah will be working in conjunction with the FDA, and collaborative clinical trial groups focused on SMA to develop well-controlled multicenter trials to fully evaluate sodium phenylbutyrate in the treatment of SMA. Tikvah Therapeutics is also supporting research on new diagnostic approaches and new therapeutic approaches to the treatment of SMA and allied neurodegenerative diseases such as ALS (amyotropic lateral sclerois) and MS (multiple sclerosis).

Click here to view Tikvah’s entire announcement.

Spinal muscular atrophy (SMA) researchers Tristan Coady and Travis Baughan, from FightSMA Science Director Dr. Chris Lorson’s laboratory at the University of Missouri, will attend and present their studies at the American Society of Gene Therapy (ASGT) Meeting in Seattle, May 30th – June 3rd.

At this year’s ASGT meeting Travis will present, “Modulating SMN2 pre-mRNA splicing: Identification of optimal targets for bi-functional RNAs.” Travis has developed second generation bi-functional RNAs that target repressor elements within SMN2 while recruiting positive factors to facilitate exon7 inclusion. Bi-functional RNAs have two functional domains, one that is a RNA sequence complimentary to the target RNA (in this case SMN2) and another that serves as a binding substrate for splicing factors which in turn promote full-length SMN expression. The original observations concerning the successful application of first generation bi-functional RNAs to alter SMN2 splicing and promote increased inclusion of exon7 were reported in the journal Molecular Therapy, 2006. The current goal of these studies is to validate the effectiveness of bi-functional RNAs in mouse models of SMA. The successful application of this technology in SMA to promote inclusion of SMN2 exon7 can be easily adapted to other diseases that are a result of aberrant pre-mRNA splicing.

Another therapeutic approach being investigated by Tristan Coady is the application of trans-splicing. Trans-splicing relies upon pre-mRNA splicing occurring between two different molecules; the endogenous RNA (for example SMN2) and the therapeutic RNA. The therapeutic RNA used in these studies contains SMN1 exon7 which when trans-spliced will form an mRNA with exons1-6 of SMN2 and exon7 of SMN1. Tristan’s studies have successfully identified trans-splicing RNAs that increase expression of full-length SMN and produce elevated levels of SMN in SMA patient fibroblasts. These studies are currently in press in the journal Molecular Therapy. The functionality of these trans-spliced RNAs is currently being tested in both tissue culture and mouse models. Tristan will present a podium presentation at the ASGT meeting entitled, “SMA Based Therapeutic Trans-Splicing RNAs Repair SMN1 Deficiency.”

FightSMA is a proud sponsor of the 10th Annual ASGT Meeting and will also be present in the Exhibit Hall at booth 324. Visitors to the booth can receive information about FightSMA research funding opportunities and can meet FightSMA scientific representatives Dr. Chris Lorson and Dr. Monique Lorson, both of the University of Missouri.

Recently, Fight SMA and the biopharmaceutical firm PTC Therapeutics announced they’re collaborating in the effort to discover new treatments for spinal muscular atrophy (SMA).  PTC issued a progress update on that work today.

Read PTC’s progress update in PDF format here.

An article published this week by PLoS Biology outlined promising research being conducted at Cold Spring Harbor Laboratory (CSHL). Researchers say they have effectively corrected an mRNA splicing defect found in spinal muscular atrophy (SMA) patients. The technique is now ready to be tested in mouse models.

“SMA patients who suffer from motor-neuron degeneration may benefit from our ability to correct the mRNA splicing defect that makes their SMN2 genes only partially functional,” suggested CSHL Professor Adrian Krainer, Ph.D.

RNA splicing antisense technology allows researchers to influence the ultimate structure and function of proteins. Proteins are synthesized from instructions coded in the DNA through a multi-step process that includes RNA splicing. Information stored in the DNA of genes is transcribed into immature “pre-messenger RNAs” (pre-mRNAs), pre-mRNAs are then spliced into mature “messenger RNAs” (mRNAs), and finally, mRNAs are translated into proteins. In humans and most other organisms, the splicing process thus ensures proper protein production.

“Targeting the splicing process is a promising strategy for finding new medicines to treat SMA, and possibly other diseases,” said Marcus Rhoades, Ph.D. of the National Institute of General Medical Sciences, which partially supported Krainer’s research. “This work brings us one step closer to that goal.”

CSHL is a private, non-profit research and education institution dedicated to exploring molecular biology and genetics in order to advance the understanding and ability to diagnose and treat cancers, neurological diseases, and other causes of human suffering. For more information visit http://www.cshl.edu/

The research is funded by the Spinal Muscular Atrophy Foundation.

For more information, you can read the news release at Medical News Today. Details on the research are available at PLoS Biology.