A New Approach to Treating Tauopathy by Lowering Apolipoprotein E

Chao Wang, PhD
Washington University School of Medicine (Saint Louis, MO)
Year Awarded:
2018
Grant Duration:
July 1, 2018 to June 30, 2020
Disease:
Alzheimer's Disease
Award Amount:
$150,000
Grant Reference ID:
A2018128F
Award Type:
Postdoctoral Fellowship
Award Region:
US Midwestern
Chao Wang, PhD

LDLR-targeted Therapy for ApoE-related Tauopathy

Summary

Tau protein aggregation in neurons is one of the hallmarks of Alzheimer’s disease (AD). The APOE gene is a strong risk factor for AD and directly affects tau pathology and tau-mediated neurodegeneration. Therefore, we will ask if decreasing apoE levels in the brain can alter tau aggregation and tau-induced neurodegeneration, and we will also try to determine how apoE exerts its effects on tau. Understanding these questions will potentially help us to develop novel treatments for AD.

Details

The goal of this study is to determine if targeting apolipoprotein E (apoE) via low-density lipoprotein receptor (LDLR) in the adult brain is a viable, novel therapy for tauopathy and tau-mediated neurodegeneration. 

The lab of David Holtzman has recently reported that apoE isoforms directly affect tauopathy and tau-mediated neurodegeneration in a mouse model that develops Alzheimer’s-type brain damage. ApoE4, a strong risk factor for Alzheimer’s disease (AD), results in increased tau levels, a strong inflammatory response, and neurodegeneration compared to other apoE isoforms. In the first aim of the current project, we are overexpressing LDLR in the brain of tau transgenic mice that also express human apoE. This is being done with a novel gene therapy approach. LDLR is a key apoE receptor that binds to apoE and regulates its cellular uptake and clearance. We will assess the effects of LDLR overexpression on tau pathology, gene expression, regional brain volume and neuronal layer thickness by histological and biochemical approaches. We will also assess behavior.

In the second aim, we are studying whether detrimental effects of apoE on tau-mediated neuronal injury occur via an apoE-receptor-associated process. For this purpose, we are performing various cell culture studies. We are inhibiting receptor function and knocking down receptor levels through specific gene targeting approach. We will assess the apoE-induced neuronal damage.

ApoE-targeted AD therapy has largely focused on apoE/amyloid-β interactions. However, growing evidence suggests that apoE directly affects tau pathology and tau-mediated neurodegeneration. In this project, we are investigating a novel LDLR-targeted therapy for apoE-related tauopathy in the absence or presence of pre-existing pathology. In addition to evaluating the efficacy of this approach, we also aim to investigate the mechanisms underlying the detrimental effects of apoE on tau-mediated neuronal injury.
If the proposed overexpression of LDLR in experiments shows a significant reduction of tauopathy or brain damage, it may potentially provide an efficient way to alter tau aggregation and tau-induced neurodegeneration. If the detrimental effects of apoE on tau-mediated neurodegeneration is an apoE-receptor-dependent process, we might be able to develop unique therapeutic strategies to target apoE receptor/signaling pathways to influence tau pathology and neurodegeneration.

About the Researcher

I first engaged in Alzheimer’s disease (AD)-related research during my PhD training in the Medical Biochemistry and Biophysics Department at the Umea University, Sweden. My PhD research mainly focused on the role of the pro-inflammatory protein S100A9 in the amyloid-neuroinflammatory cascade in AD and traumatic brain injury. Since 2017, I have been pursuing my post-doctoral training with Dr. David Holtzman, MD, in the Department of Neurology at Washington University in St. Louis. My research now is focused on understanding how LDLR affects apoE4-related tau pathology and brain dysfunction.

Personal Story

My journey with Alzheimer’s disease (AD) research started during my master’s degree, seven  years ago. Today, there are very few people who have not been affected by AD. Consequently, personal stories and anecdotes of the hardships shared by my loved ones naturally captivated me to study this topic.  In my native country of China, the healthcare options offered to patients with AD is shockingly scarce compared to some other diseases, like cancer and hepatitis, especially in the rural areas where I grew up. As such, there is a dramatic decline of the quality of life for patients, families, and caretakers. Nowadays, in China, the population is aging rapidly due to the one-child policy that was introduced about three decades ago. Even after the policy was terminated in 2015, the fertility rate has not seen significant improvement. With the rapidly aging population, the long-term care for patients with AD will soon become a severe social issue on a global scale. It is imperative that effective strategies to reduce the occurrence of the disease are developed and that the disease be cured in the near future. I am very thankful for the BrightFocus Foundation and its donors for their indispensable support and I sincerely hope we may one day help contribute to the development of an innovative way to treat AD. 

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