Johns Hopkins Medicine study finds targeting the Aplp1 and Lag3 interaction could slow the progression of Parkinson’s and potentially treat other neurodegenerative diseases.
Johns Hopkins Medicine researchers have discovered a new potential biological target for halting the spread of Parkinson’s disease-causing alpha-synuclein in studies with genetically engineered mice. They have identified Aplp1, a cell surface protein, as a key player in this process.
The findings, published May 31 in Johns Hopkins researchers have identified. The process, parthanatos (from the Greek word for “death”), leads to impairments in movement, emotional regulation and thinking.
Aplp1’s bond with Lag3 on the cell’s surface enables healthy brain cells to absorb traveling clumps of alpha-synuclein, leading to cell death, the researchers say.
In mouse studies published in 2016 and 2021, Mao and Dawson’s team identified Lag3’s role in binding with alpha-synuclein proteins, causing Parkinson’s disease to spread. However, those studies indicated that another protein was partially responsible for the cell’s absorption of misfolded alpha-synuclein.
“Our work previously demonstrated that Lag3 wasn’t the only cell surface protein that helped neurons absorb alpha-synuclein, so we turned to Aplp1 in our most recent experiments,” says Valina Dawson.
Recent Experimental Insights
To determine whether Aplp1 indeed contributed to the spread of harmful alpha-synuclein proteins, researchers used a line of genetically engineered mice lacking either Aplp1 or Lag3 or both Aplp1 and Lag3. In mice without Aplp1 and Lag3, cell absorption of the harmful alpha-synuclein protein dropped by 90%. After injecting mice with the Lag3 antibody, they found that this drug also blocks the interaction of Aplp1 and Lag3, meaning healthy brain cells could no longer absorb disease-causing alpha-synuclein clumps.
The researchers say the Lag3 antibody nivolumab/relatlimab, a drug FDA approved in 2022 for cancer treatment, could play a role in preventing cells from absorbing alpha-synuclein.
“The anti-Lag3 antibody was successful in preventing further spread of alpha-synuclein seeds in the mouse models and exhibited better efficacy than Lag3-depletion because of Aplp1’s close association with Lag3,” Ted Dawson says.
This research has potential applications in treating other neurodegenerative conditions that have no cures, Mao says. In could try to target Lag3 — which also binds with the dementia-related tau protein — with the same antibody.
With the success of using the Lag3 antibody in mice, Ted Dawson says the next steps would be to conduct anti-Lag3 antibody trials in mice with Parkinson’s disease and Alzheimer’s disease. The Johns Hopkins researchers are also looking into how they could prevent unhealthy cells from releasing disease-causing alpha-synuclein in the first place.
Reference: “Aplp1 interacts with Lag3 to facilitate transmission of pathologic α-synuclein” by Xiaobo Mao, Hao Gu, Donghoon Kim, Yasuyoshi Kimura, Ning Wang, Enquan Xu, Ramhari Kumbhar, Xiaotian Ming, Haibo Wang, Chan Chen, Shengnan Zhang, Chunyu Jia, Yuqing Liu, Hetao Bian, Senthilkumar S. Karuppagounder, Fatih Akkentli, Qi Chen, Longgang Jia, Heehong Hwang, Su Hyun Lee, Xiyu Ke, Michael Chang, Amanda Li, Jun Yang, Cyrus Rastegar, Manjari Sriparna, Preston Ge, Saurav Brahmachari, Sangjune Kim, Shu Zhang, Yasushi Shimoda, Martina Saar, Haiqing Liu, Sin Ho Kweon, Mingyao Ying, Creg J. Workman, Dario A. A. Vignali, Ulrike C. Muller, Cong Liu, Han Seok Ko, Valina L. Dawson and Ted M. Dawson, 31 May 2024, Nature Communications.
DOI: 10.1038/s41467-024-49016-3
Other researchers on this study are Hao Gu, Donghoon Kim, Yasuyoshi Kimura, Ning Wang, Enquan Xu, Ramhari Kumbhar, Xiaotian Ming, Haibo Wang, Chan Chen, Shengnan Zhang, Chunyu Jia, Yuqing Liu, Hetao Bian, Senthilkumar Karuppagounder, Fatih Akkentli, Qi Chen, Longgang Jia, Heehong Hwang, Su Hyun Lee, Xiyu Ke, Michael Chang, Amanda Li, Jun Yang, Cyrus Rastegar, Manjari Sriparna, Preston Ge, Saurav Brahmachari, Sangjune Kim, Shu Zhang, Haiqing Liu, Sin Ho Kweon, Mingyao Ying and Han Seok Ko from Johns Hopkins; Yasushi Shimoda from the Nagaoka University of Technology; Martina Saar and Ulrike Muller from Heidelberg University; Creg Workman and Dario Vignali of the University of Pittsburgh School of Medicine and Cong Liu of the Chinese Academy of Sciences.
This work was supported by grants from the