Why this is important

Cerebral palsy is the most common childhood physical disability, according to the Centers for Disease Control. It affects an estimated 1 in 345 children. 

Missed developmental milestones are currently the best tool for diagnosing cerebral palsy. There is no genetic test for it.

“If you could diagnose CP sooner, you could have better interventions, better physical therapy for muscle training to improve quality of life of patients,” said Batish, an associate professor of medical and molecular sciences at UD. “What we need is a molecular marker, something that can definitively say you have it. I want to leverage synthetic biology tools and data to better define exactly what’s going on.”

About the work

Working in collaboration with researchers at Nemours Children’s Health, Batish evaluated muscle samples from patients with and without CP. She and UD doctoral candidate Brigette Romero then grew the stem cells responsible for making muscle in the lab to look at the expression of circNFIX, which plays a role in muscle development.

Normally, Batish explained, there are typically about 10 to 15 copies of a given circular RNA in a cell. With circNFIX, however, the Batish lab found about 60 copies per cell, the highest expression of circular RNAs found in the samples they studied. 

But in muscle cells with CP, the research team found the level of circNFIX was reduced. 

“This means that in normal functioning cells, circNFIX is doing something necessary. When circNFIX is low, the activity it provides is lost,” said Batish.

Other researchers had found that circNFIX controlled muscle development by regulating the expression of an important protein called myocyte-specific enhancer factor (MEF2C) that is required for proper muscle formation in mouse models. It does this by controlling the function of another regulatory RNA, called microRNA. In doing so, the amount of MEF2C protein expression increases, which then “turns on” the genes needed to form muscle. 

The UD research team tested this theory and found that when the circNFIX was taken away, a specific microRNA runs rogue and attaches to the MEF2C, blocking its ability to make the protein necessary for proper muscle production. Further, this led to less MEF2C being found in the skeletal muscle tissue, potentially causing shortened and dysfunctional muscle fibers.

While it was known that muscle formation is upset in cerebral palsy, Batish said this is the first study to identify the role of circular RNAs in human muscle development in CP. The insight that the lack of a particular circular RNA sets in motion a process that suppresses MEF2C in muscle cells with CP is also novel.

Future potential

The team’s findings are a forward step that will open new lines of inquiry, allowing researchers to explore what else may be controlling MEF2C at the cellular level. Importantly, the work also opens the door to look beyond diagnostics and consider therapeutic angles, like whether it is possible to supplement MEF2C to either reduce symptoms or increase muscle formation.

In her own research, Batish wants to look more closely at whether circNFIX is controlling other important proteins in cerebral palsy. 

CP has many confounding factors, including the need to wait for symptoms to appear to diagnose. Identifying targeted markers, “real objective things that are yes or no answers,” will be critical. Batish was clear that it must be something that researchers can reproducibly see and that is highly sensitive and specific. The dream, she said, is a test that can be done prenatally or at time of birth, with the baby’s first blood screening.

“At the end of the day, diagnosis must become more specific. Every disease has a cause, and history tells us that for any cancer where we have found the gene responsible, we increased survival rates and improved the outcomes,” said Batish. “We must do this for many other diseases, especially frequent diseases that affect children, like cerebral palsy.”

The researchers reported their findings in the Journal of Biological Chemistry.