Scientists Identify Key Protein Driving Alzheimer’s Brain Cell Death

Scientists have identified the 1N4R tau isoform as a key driver of Alzheimer’s disease, paving the way for potential new treatments.

A research team at the University of Cologne has made a key discovery about the role of the tau protein in Alzheimer’s disease. Using human-induced pluripotent stem cells (iPSCs), the team demonstrated that a specific tau protein variant, the 1N4R isoform, is responsible for triggering the toxic effects of protein clumps in human brain cells.

The findings, published in Alzheimer’s & Dementia, were led by Dr. Hans Zempel from the Institute of Human Genetics. Dr. Zempel is also a group leader in the Career Advancement Program (CAP) at the Center for Molecular Medicine Cologne (CMMC), affiliated with both the University of Cologne and University Hospital Cologne.

Understanding the Impact of Protein Clumps in Alzheimer’s

If a person suffers from Alzheimer’s disease, certain proteins accumulate in brain cells, forming clumps that restrict normal cell function or even cause the cell to die. Dr. Buchholz and Dr. Zempel’s team have used state-of-the-art techniques such as CRISPR/Cas9 gene editing and live-cell imaging in human induced pluripotent stem cells (iPSCs) to demonstrate that the 1N4R tau isoform is responsible for the pathological effects on the cell. iPSCs are human stem cells that are generated from other cells.

For example, skin cells can be reprogrammed into iPSCs and from there transformed into brain cells (neurons). The researchers tested different forms of the tau protein by expressing them specifically in nerve cells. In this way, the researchers were able to analyze how each protein isoform affects the cell.

A Step Toward New Treatment Targets

According to Dr Sarah Buchholz, first author of the study, “this study represents a significant advance in helping us to understand the mechanisms of Alzheimer’s disease. By identifying 1N4R tau as a key protein, we have discovered a potential new target for future treatments.”

The study’s interdisciplinary approach not only helps to better understand Alzheimer’s disease but also demonstrates the importance of human cell models in neurodegenerative research. Further studies are needed to translate the results of this study into clinical application, in particular, to validate the results in adequate animal models and to develop specific therapeutics that will intervene in this process.

Reference: “The tau isoform 1N4R confers vulnerability of MAPT knockout human iPSC-derived neurons to amyloid beta and phosphorylated tau-induced neuronal dysfunction” by Sarah Buchholz, Mohamed Aghyad Al Kabbani, Michael Bell-Simons, Lena Kluge, Cagla Cagmak, Jennifer Klimek, Natja Haag, Lukas C. Iohan, Audrey Coulon, Marcos R. Costa, Devrim Kilinc and Hans Zempel, 28 February 2025, Alzheimer’s & Dementia.
DOI: 10.1002/alz.14403

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