Not long ago, Professor Jiang Yong from the Department of Neurosurgery, Affiliated Hospital of Southwest Medical University, in collaboration with Professor Li Tao from West China Hospital of Sichuan University and Professor Cao Yang from University of Science and Technology of China, published the latest research findings titled “Astrocytic LRP1 enables mitochondria transfer to neurons and mitigates brain ischemic stroke by suppressing ARF1 lactylation” in the field of “Endocrinology and Metabolism”.
This study first revealed the mechanism by which LRP1 regulates the lactylation modification of ARF1 by adjusting cell metabolism, thereby controlling the transfer of mitochondria between astrocytes and neuronal cells. It is worth mentioning that this process can antagonize neural damage after cerebral ischemia.

We have a dialogue with Dr. Zhou Jian, the first author of the article, to learn about the important regulatory role of Low-Density Lipoprotein Receptor-Related Protein 1 (LRP1) in the mitochondrial transport of astrocytes.

Deep Dive into the LRP1 Regulation Mechanism

State-of-the-art equipment fuels cerebrovascular research

Amidst the growing concerns of an aging population and the youthful trend of disease onset, an increasing number of individuals are at risk of cerebrovascular diseases, imposing a significant burden on society. Dr. Zhou Jian has primarily dedicated his focus to the field of cerebrovascular research, with the intent of uncovering the pathogenesis of these diseases to guide the development of novel therapeutic targets. This effort aims to enhance the survival rates, improve prognosis, and elevate the quality of life for patients suffering from cerebrovascular conditions.

In 2016, Nature reported that astrocytes could mitigate neuronal damage post-cerebral ischemia by modulating the activity of CD38 cyclase to transfer mitochondria to neurons. Consequently, the transfer of mitochondria between astrocytes and neuronal cells is crucial for sustaining the aerobic respiration and energy supply of neuronal cells. Interventions targeting mitochondrial transfer have demonstrated promising potential in the prevention and treatment of diseases.

However, the precise mechanism by which astrocytes modulate mitochondrial transfer to alleviate ischemic stroke requires further in-depth investigation. With this in mind, the team, building on previous reports regarding the involvement of LRP1 in the regulation of the nervous system, established a research topic examining the regulatory role of LRP1 in the mitochondrial transport of astrocytes.

The team first confirmed the possibility of a novel mechanism by which LRP1 regulates the extrusion of mitochondria in astrocytes. They further explored the impact of LRP1 on astrocyte metabolism, using cellular models to uncover the role of ARF1 K73 lactylation in the regulation of mitochondrial extrusion in astrocytes. Subsequently, through animal models targeting astrocyte LRP1 expression and overexpressing the ARF1 lactylation mutation, they discovered that the reduction of LRP1 or the promotion of ARF1 lactylation could lead to a decrease in the number of mitochondria derived from astrocytes in the cerebrospinal fluid, thereby validating this regulatory mechanism. The team then established a cerebral ischemia animal model and, using 7.0T magnetic resonance, behavioral assessment, and confocal microscopy, confirmed the significant role of the LRP1-ARF1 Kla(73) axis in the regulation of mitochondrial transport in astrocytes. Finally, the team further substantiated their research findings with clinical samples from stroke patients.

When exploring the mechanism using cellular models, the team utilized both cell line models and primary cell models for dual verification. The RWD single-cell suspension preparation instrument played a crucial role in obtaining primary cells from animal samples. Dr. Zhou remarked, “Previously, our manual glass homogenization only yielded a survival rate of 70%-80%. After switching to the single-cell suspension, the survival rate has been around 90%, with one instance reaching 97%. We also performed fluorescence staining, which, in conjunction with fluorescence assessment using a cell counter, showed excellent results. Hence, when sorting neuronal cells, we firmly choose to use the single-cell suspension preparation instrument. After all, neuronal cells are more fragile compared to glial cells, and the performance of this device has been highly satisfactory for us.”

In terms of animal experiments, the team’s deep-rooted connection with RWD dates back to 2018. Dr. Zhou said, “At that time, we typically used peritoneal anesthesia for animal experiments. Later, due to some ethical considerations regarding animals, we began to explore inhalation anesthesia and purchased RWD’s machine. As we became more familiar with it, we found the equipment quite user-friendly and gradually acquired more, which indeed provided considerable convenience for our experiments.”
Given that team members are predominantly neurosurgeons skilled in delicate microsurgical operations, they tend to select modeling, detection, and drug administration methods that meet research requirements, even if the processes are intricate.

MCAO modelling was conducted using the suture-occluded method, and the degree of cerebral ischemia in the MCAO model was assessed with specialized equipment. Dr. Zhou said, “When studying in the United States, my colleagues recommended RWD’s laser speckle device, stating its significant utility for cerebrovascular research. After using it, we found the device extremely beneficial for studying and evaluating cerebral ischemia.” Dr. Zhou added.

“For drug administration experiments, it was necessary to continuously administer medication to the mouse’s lateral ventricle for seven days. After comparison, we found RWD’s controlled-release pump to be the most cost-effective.”

Step Out of the Comfort Zone
Explore New Experimental Technologies and Methods

Throughout Dr. Zhou’s project journey, “innovation” has been pivotal, a term that frequently emerged in his interview.

For Dr. Zhou, continuing with basic research under the guidance of his senior fellow could have also yielded results and ensured a smooth graduation. However, he chose to step out of his comfort zone and, with strong support from his mentor, ventured beyond the platform in Luzhou to collaborate with Professor Li Tao’s team at West China Hospital, attempting to explore new horizons.

But innovation also implies uncertainty and arduousness. This research spanned approximately five years from initiation to publication. As the first author, Dr. Zhou faced immense pressure. He candidly shared that the greatest challenge along the way was his lack of self-confidence and reluctance to tackle difficulties. Nevertheless, despite the hardships of scientific research, it remains his passion. With the support of his family, encouragement from his mentor, and teamwork, he found the motivation and confidence to persevere. Dr. Zhou’s inner strength grew throughout this process, withstanding pressures and advancing to where he is today. He reflected, “Experiments are never smooth sailing; there are always many uncontrollable factors, and the results are not as expected. Only by continuously adjusting one’s mindset and broadening one’s perspective can one discover the ultimate truth.”

A village bright with willows and blossoms emerges after the dark willows, and the fruitful project began on a bus laden with disappointment and sorrow.

“Not to be laughed at, but the project was actually conceptualized on a bus,” Dr. Zhou said with a smile, “At that time, after a few months of unsatisfactory results studying under Professor Li Tao, I was dejectedly preparing to return to Luzhou. I distinctly remember December 19th, on the bus back to Luzhou from Chengdu, sitting in the last row by the window, feeling particularly melancholic. Suddenly, Professor Li Tao called for a discussion, and I immediately started checking the literature and reporting on the bus, which is how we established the research direction.”

After a pause, Dr. Zhou said, “Looking back, it’s quite interesting. It was as if you were at the bottom of a well, and suddenly someone threw down a rope. I saw hope, grabbed it, and it lifted me up just in time.”
After establishing the research direction, new challenges arose. “Our experiments required an assessment of the cerebrovascular condition, which was new to us. After research and repeated trials, we chose laser speckle of RWD for the comparative experiment.”

However, the heavy and complex nature of research work made balancing clinical duties and scientific research a daunting challenge. The average duration of a neurosurgery operation often exceeds four hours, and there is also the need to oversee clinical practice for undergraduate students. Additionally, as this project was a joint collaboration with West China Hospital, Dr. Zhou frequently travelled to Chongqing and Chengdu for experiments. He admitted that it is hard to balance clinical practice and scientific research. So, how did the experiments proceed? “When in the clinic, more than 90% of my focus was on clinical work, and during that time, some simple research tasks were handed over to other members of the research group. When it came to new experiments that required significant breakthroughs, I basically stepped away from clinical work entirely and devoted myself fully to research. It’s hard to have the best of both worlds; there must be sacrifices to achieve something,” Dr. Zhou replied.
As for the future, Dr. Zhou still hopes to do his best in his job, becoming a clinical doctor who brings benefits to the community. “Of course, I also hope to make more breakthroughs in my limited energy and serve clinical practice better.”

We also hope Dr. Zhou continues to shine in the field he loves and make greater contributions to the medical profession.

Every dedicated research professional deserves our admiration and respect. We are honored that our product can contribute to their valuable work.