Researchers from Tel Aviv University, the Technion, and Cornell wrapped antibodies in temporary chemical “camouflage” and packaged them in fatty nanoparticles. In a preclinical model, the antibodies were able to reach nerve cells and reduce alpha-synuclein aggregates – but the road to human trials is still long.
Based treatments Antibodies In recent decades, they have brought about a significant change in the treatment of cancer, autoimmune diseases, and inflammatory diseases. Antibodies are capable of identifying molecular targets with great precision, but they have a major limitation: due to their size and electrical charge, they do not easily penetrate the cell membrane, so most of them act on targets located outside cells or on their surface.
The limitation is particularly great when trying to treat brain diseases. On the way to the nerve cells, the drug must pass through The blood-brain barrier, and then it must also penetrate through the cell membrane to reach the proteins that accumulate inside it.
Collaboration between Tel Aviv University, The Technion And Cornell University presents a method designed to overcome both barriers. The researchers gave the antibodies a temporary chemical “camouflage,” packaged them inFatty nanoparticles And guided them into the cells. After entering, the antibodies were released from the envelope and returned to their original activity.
The study, published in the journal Proceedings of the National Academy of Sciences – PNAS, included experiments in cells as well as experiments in preclinical models of Parkinson's disease and acute inflammatory lung injury.
Why is it difficult to get an antibody into a cell?
Antibodies are large proteins. This property helps them recognize target molecules with great precision, but prevents them from freely passing through cell membranes. As a result, most existing antibody drugs act on receptors or proteins located outside the cell.
However, many of the proteins involved in diseases are actually found inside the cell, in the cytoplasm or in internal organelles. If you want to use an antibody to neutralize such a protein, you need a system that will transport it intact into the cell without damaging its binding ability.
The research was led by Prof. Ben Maoz from the Faculty of Engineering and the Sagol School of Neuroscience at Tel Aviv University, Prof. Uri Asheri from the Faculty of Life Sciences and the Sagol School of Neuroscience, and Prof. Christopher Albee from Cornell University. The research was also participated in by Prof. Avi Schroeder's group from the Technion.
Temporary chemical camouflage
The method is based on a synthetic molecule called SL4, which temporarily attaches to the surface of the antibody and changes its electrical charge. The change allows the large antibody to be efficiently incorporated into lipid nanoparticles or LNPs.
Lipid nanoparticles are best known to the public for their use in mRNA vaccines against the coronavirus, where they were used to deliver RNA molecules into cells. In the current study, they were used to deliver much larger and more complex proteins: full-length antibodies.
After the nanoparticle enters the cell, the bond between SL4 and the antibody breaks down. The antibody essentially removes the "camouflage," returns to its original structure, and can bind to the target protein inside the cell.
The researchers tested the method using several antibodies and several cell types. In experiments in cell cultures, the antibodies were able to penetrate and affect proteins involved in signaling pathways related to inflammation and cancer.
Reduce alpha-synuclein aggregates
One of the applications tested was an antibody directed against Alpha-synucleinThis is a protein found naturally in nerve cells, but in Parkinson's disease and other degenerative diseases it may fold abnormally and accumulate in pathological aggregates.
Since much of alpha-synuclein is found inside nerve cells, it is difficult for conventional antibodies to reach it. The researchers packaged an anti-alpha-synuclein antibody into brain-targeted nanoparticles and delivered it systemically in a preclinical model of the disease.
After treatment, a decrease in the amount of pathological alpha-synuclein aggregates in nerve cells was measured. This finding indicates that the antibody reached its intracellular target and retained its ability to recognize the protein.
However, this does not mean that the technology has cured Parkinson's or has been proven to be a treatment in humans. The research at this stage is intended to show that the antibodies can reach cells in a living system and act against targets that were previously difficult to access.
From brain diseases to pneumonia
To test whether this is a general method and not a solution suitable only for one antibody, the researchers also tested the platform in a model of acute inflammatory lung injury.
In this case, the nanoparticles carried antibodies against RelA, a component of the NF-κB pathway that triggers inflammatory responses. Introducing the antibodies into the cells reduced inflammatory markers and improved the condition of the lung tissue in the experimental model.
The use of two different models – one in the brain and one in the lung – demonstrates that both the antibody and the nanoparticle shell can be tailored to the organ and target protein. For the researchers, this is the main advantage of the platform: the possibility of using existing antibodies against intracellular targets that were previously inaccessible to them.
Not yet a treatment for Parkinson's patients
The development is in the preclinical stage. Before it can be tested in Parkinson's patients, further studies will be required on the safety of the nanoparticles, their distribution in the body, the duration of the antibodies' action, and their ability to reach the appropriate areas of the human brain.
It will also be necessary to test whether the treatment can be given repeatedly without provoking an immune response against the components of the envelope or against the antibody itself. In addition, the blood-brain barrier in humans and human Parkinson's disease are more complex than the models used in the laboratory.
Another question is whether reducing alpha-synuclein accumulations after the disease has already begun could protect nerve cells and improve symptoms over time. The current study demonstrates the antibody's target and molecular effect, but does not yet provide a clinical answer to this question.
Despite the reservations, the ability to deliver intact antibodies into the cell opens up a broad research direction. If the method passes safety and efficacy tests, it may enable the development of biological drugs Against intracellular targets in degenerative diseases of the nervous system, inflammatory diseases, and certain types of cancer.
The scientific article
Intracellular delivery of full-length antibodies via organ-targeted lipid nanoparticles, the journal (PNAS), TWO: 10.1073 / pnas.2531649123.
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