Scientists from the Institute for Bioengineering of Catalonia (IBEC), located at the Barcelona Science Park, with researchers from the Northwestern University, have developed a new approach that directly combats the progression of neurodegenerative diseases like Alzheimer’s disease and amyotrophic lateral sclerosis (ALS). The study, published in the Journal of the American Chemical Society reveals a new therapy, made of nanofibers and trehalose, a sugar that naturally occurs in plants, traps and neutralizes toxic proteins to stop disease progression. Now trapped, the toxic proteins can no longer enter neurons and instead harmlessly degrade.

In these devastating illnesses, proteins misfold and clump together around brain and spinal cord neural cells, which ultimately leads to cell death. The innovative new treatment effectively traps the proteins before they can aggregate into the toxic structures capable of penetrating neurons. The trapped proteins then harmlessly degrade in the body.

The “clean-up” strategy significantly boosted the survival of lab-grown human neurons under stress from disease-causing proteins. Designated as an ACS Editors’ Choice article, the study was published today in the Journal of the American Chemical Society.

“Our study highlights the exciting potential of molecularly engineered nanomaterials to address the root causes of neurodegenerative diseases,” said Northwestern’s Samuel I. Stupp, one of the study’s senior authors of this project. “In many of these diseases, proteins lose their functional folded structure and aggregate to make destructive fibers that enter neurons and are highly toxic to them”.

“Our treatment works by trapping misfolded proteins and preventing them from forming toxic aggregates at an early stage. This includes blocking the formation of soluble oligomers and short amyloid fibers—structures known to penetrate neurons and cause the most damage. With continued research, we believe this approach could significantly slow the progression of the disease” Said Zaida Álvarez, group leader at the Biomaterials for neural regeneration group at IBEC and senior author of this project.

SEM image of Electron Nanofibers taken in a UNC lab. / Credit: Deander4, CC BY-SA 4.0, via Wikimedia Commons.

A sugar-coated solution

According to the World Health Organization (OMS), as many as 50 million people worldwide might have a neurodegenerative disorder. Most of these diseases are characterized by the accumulation of misfolded proteins in the brain, leading to the progressive loss of neurons. While current treatments offer limited relief, a dire need for new therapies remains.

To tackle this challenge, the researchers turned to a class of peptide amphiphiles that contain modified chains of amino acids. Peptide amphiphiles are already used in well-known pharmaceuticals including semaglutide, or Ozempic. In fact, the Northwestern investigators developed a similar molecule in 2012 that boosted insulin production.

“The advantage of peptide-based drugs is that they degrade into nutrients,” Stupp said. “The molecules in this novel therapeutic concept break down into harmless lipids, amino acids and sugars. That means there are fewer adverse side effects.” To develop a peptide amphiphile to treat neurodegenerative diseases, his team added an extra ingredient: a natural sugar called trehalose.

“Trehalose is naturally occurring in plants, fungi and insects,” explained first author from Northwestern University,  Zijun Gao. “It protects them from changing temperatures, especially dehydration and freezing. Others have discovered trehalose can protect many biological macromolecules, including proteins. So, we wanted to see if we could use it to stabilize misfolded proteins.”

Instability is key

When added to water, the peptide amphiphiles self-assembled into nanofibers coated with trehalose. Surprisingly, the trehalose destabilized the nanofibers. Although it seems counterintuitive, this decreased stability exhibited a beneficial effect.

By themselves, the nanofibers are strong and well-ordered — and resistant to rearranging their structure. That makes it more difficult for other molecules, like misfolded proteins, to integrate into the fibers. Less stable fibers, on the other hand, became more dynamic — and more likely to find and interact with toxic proteins.

“Unstable assemblies of molecules are very reactive,” Samuel I. Stupp said. “They want to interact with and bond to other molecules. If the nanofibers were stable, they would happily ignore everything around them”.

Searching for stability, the nanofibers bonded to amyloid-beta proteins, a key culprit implicated in Alzheimer’s disease. But the nanofibers didn’t just stop the amyloid-beta proteins from clumping together. The nanofibers fully incorporated the proteins into their own fibrous structures — permanently trapping them into stable filaments.

“Then, it’s no longer a peptide amphiphile fiber anymore,” Zijun Gao said. “But a new hybrid structure comprising both the peptide amphiphile and the amyloid-beta protein. That means the nasty amyloid-beta proteins, which would have formed amyloid fibers, are trapped. They can no longer penetrate the neurons and kill them. It’s like a clean-up crew for misfolded proteins.

Improving neuron survival

To assess the therapeutic potential of the new approach, the scientists conducted laboratory tests using human neurons derived from stem cells. The results showed the trehalose-coated nanofibers significantly improved the survival of both motor and cortical neurons when exposed to the toxic amyloid-beta protein.

The novel approach of using unstable nanofibers to trap proteins offers a promising avenue for developing new and effective therapies for Alzheimer’s, ALS and other neurodegenerative conditions. Much like cancer treatments combine multiple therapies — like chemotherapy and surgery or hormone therapy and radiation —the nanotherapy might be most effective when combined with other treatments.

“Our therapy might work best when targeting diseases at an earlier stage — before aggregated proteins enter cells,” Zaida Álvarez said. “But it’s challenging to diagnose these diseases at early stages. So, it could be combined with therapies that target later-stage symptoms of the disease. Then, it could be a double whammy”.

» Article of reference: Zijun Gao, Ruomeng Qiu, Dhwanit R. Dave, Palash Chandravanshi, Gisele P. Soares, Cara S. Smith, J. Alberto Ortega, Liam C. Palmer, Zaida Álvarez, and Samuel I. Stupp. Supramolecular Copolymerization of Glycopeptide Amphiphiles and Amyloid Peptides Improves Neuron Survival. Journal of the American Chemical Society (2025). doi: 10.1021/jacs.5c00105

» Link to the news: IBEC website [+]