"Could This Bring Dementia Treatment Closer? The Surprising Role of Astrocytes in the Brain... Secret to Long-Lasting Memory Uncovered [Reading Science]"

IBS and KBRI Reveal How Astrocyte Protein ‘Ank2’ Maintains Long-Term Memory
Demonstrate That Regulating Only Astrocyte Signals Enhances Memory
New Clues for Treating Dementia and Cognitive Decline

A South Korean research team has, for the first time, identified that astrocytes—not neurons—play a key role in maintaining long-lasting memories. The researchers also demonstrated through animal experiments that simply modulating a specific protein in astrocytes can help preserve memories for longer periods, suggesting new possibilities for treating cognitive decline associated with dementia and aging.

On July 7, the Institute for Basic Science (IBS) announced that its Center for Memory and Glia Research, in collaboration with the Korea Brain Research Institute (KBRI), has discovered that the protein Ank2 (Ankyrin-2) within astrocytes plays a crucial role in long-term memory retention. The study was published online the same day in the international journal Nature Communications.

A core regulatory mechanism by which astrocytes maintain long-term memory. Schematic of the long-term memory formation process. After sufficient learning, BDNF signals increase contact with engram neurons through astrocytic Ank2, allowing memories to be retained longer. Conversely, without Ank2, long-term memory weakens, but memory maintenance is restored when BDNF signaling is activated through optogenetics. Courtesy of the research team

Astrocytes, Not Neurons, Regulate Memory Retention

Until now, memory research has largely focused on neurons. However, the mechanisms by which memories are retained for weeks or even years have remained unclear.

The research team turned their attention to astrocytes, which surround neurons and regulate their activity. In particular, they hypothesized that the Ank2 protein, which is abundantly present in astrocytes, may be involved in long-term memory retention, and conducted experiments with mice.

The results showed that mice in which the Ank2 gene was deleted exclusively in astrocytes retained recent memories immediately after learning, but displayed a significant decline in long-term memory when tested two weeks later.

Furthermore, astrocytes lacking Ank2 exhibited a simpler structure and reduced physical contact with engram neurons, which are responsible for memory storage. The ability to sustain long-term potentiation (LTP)—a key process for learning and memory formation—was also found to be impaired.

Astrocytes filling the hippocampus, the key brain region for memory formation and maintenance. Astrocytes are glial cells that regulate neuronal function and play a crucial role in long-term memory retention. The research team demonstrated that selectively activating astrocyte signals alone can prolong memory retention. Provided by the research team.

The researchers explained that these findings demonstrate that astrocytes are not merely supporting cells for neurons, but play a direct role in stabilizing and maintaining long-term memories.

Stimulating Astrocyte Signals Alone Enhances Memory

The research team also uncovered the molecular mechanisms behind memory retention.

Ank2 regulates calcium signaling within astrocytes, and its absence weakens calcium signaling and reduces responsiveness to brain-derived neurotrophic factor (BDNF), which is crucial for memory formation.

Conversely, when BDNF signaling in astrocytes was selectively activated using optogenetic technology, the experimental animals retained their memories for longer than before.

Research team photo. (From left) Woohyun Ko, Research Fellow at IBS Center for Memory and Glia Research (corresponding author); Jooyoung Kim, former postdoctoral researcher at IBS Center for Memory and Glia Research (first author); Hayoung Kim, master's student at IBS Center for Memory and Glia Research (first author); Jiwoon Lim, integrated course student at IBS Center for Memory and Glia Research (first author). Courtesy of IBS

The research team explained that this study is the first to show that targeting astrocytes—rather than neurons—can improve memory retention.

Woohyun Ko, Research Fellow at the IBS Center for Memory and Glia Research, stated, "This study is significant in that it expands the perspective of memory research, which has traditionally focused on neurons, to include astrocytes. We expect it will offer new directions for research into a variety of memory-related brain disorders such as cognitive decline due to aging and depression, as well as Alzheimer's disease."

He added, "In the future, we plan to expand our research to investigate the role of astrocytic Ank2 in neurodevelopmental disorders such as autism spectrum disorder and intellectual disabilities."

This content was produced with the assistance of AI translation services.