Nanjing Normal University Qian Yong: New Ideas for Chemical Control of Epilepsy, Cell Press Dialogue with Scientists

Life sciences Life science On December 21, 2021, Professor Qian Yong’s group from the School of Chemistry and Materials Science, Nanjing Normal University published an article titled "3D two-photon brain imaging reveals dihydroartemisinin exerts" in the Cell Chemical Biology journal of Cell Press.
"antiepileptic effects by modulating iron homeostasis" is the latest research
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Professor Qian Yong’s team combined a new type of ferrous ion (Fe2+) fluorescent probe with high-throughput imaging technology to screen the lead compound dihydroartemisinin (DHA), revealing that it can alleviate the iron homeostasis of nerve cells The epileptic state of mice
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This work innovatively provides a reliable chemical tool to assess changes in the Fe2+ state in the brains of living epileptic mice, and may help to quickly discover new anti-epileptic drug candidates and provide new ideas for chemically regulating epilepsy diseases.
(Picture 1)
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Figure 1.
The design of the two-photon fluorescent probe FeP and its application in monitoring the Fe2+ flux changes in the brain of epileptic mice with DHA
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Iron is an important element of life, and a normal iron balance is the key to maintaining life and health
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Since the brain is the main organ for iron accumulation, iron overload and abnormal metabolism exist in many neurological diseases, including epilepsy
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In nerve cells, the excessive accumulation of active Fe2+ will promote the disproportionation of hydrogen peroxide to produce hydroxyl free radicals, leading to excessive oxidation of lipids and other biological molecules, and ultimately leading to neuronal cell apoptosis or iron death
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Therefore, the development of new technologies to monitor the Fe2+ status in neurons, especially the imaging of the temporal and spatial distribution of Fe2+ in the living brain, is essential for understanding the iron homeostasis in the epileptic brain
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As a non-invasive imaging method, fluorescence imaging technology is more and more widely used in neurobiology research
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But at present, there is no two-photon fluorescent probe suitable for imaging the temporal and spatial distribution of Fe2+ in epileptic brain
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The author has developed a two-photon fluorescent probe FeP with near-infrared excitation that can perform three-dimensional dynamic imaging of Fe2+ distribution.
It can pass through the blood-brain barrier and has the characteristics of targeting the brain
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The probe FeP was used to build a convenient, minimally invasive, and intuitive long-term detection platform.
For the first time, the up-regulated distribution of Fe2+ in the brain of living mice during KA-induced epilepsy was dynamically observed in vivo in real time
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The author combined high-content analysis imaging technology with FeP, and built a high-throughput cell fluorescence imaging screening platform, which provides a high-throughput screening method for studying Fe2+ in biological systems and screening potential antiepileptic drugs
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In addition, the author combined in vivo imaging with EEG monitoring, animal behavior and other studies, and preliminarily confirmed that the natural product DHA, which reduces the fluorescence intensity, has an effective therapeutic effect on KA-induced epilepsy mouse models
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Further molecular mechanism studies have found that DHA can significantly down-regulate the expression of LCN2, Ac-p53 and TfR1, and up-regulate the expression of FPN and GPX-4, thereby regulating iron homeostasis in the brain and inhibiting neuronal iron death, revealing that DHA regulates the occurrence and development of epilepsy disease Molecular mechanism (Figure 2)
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This research provides an innovative research platform for 3D brain imaging to monitor the dynamic distribution of Fe2+ related to iron homeostasis in the brain of neurological diseases.
It also provides a new strategy and method for the screening of iron homeostasis regulators, which is expected to be useful for the treatment of epilepsy.
The discovery of new chemical entities provides assistance
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Figure 2.
DHA regulates iron homeostasis in the brain of KA-induced epilepsy model mice
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This research work has been funded by scientific research projects such as the General Program of the National Natural Science Foundation of China, the Jiangsu Distinguished Professor Program, and the Open Project of the State Key Laboratory of Medical Biotechnology
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Dr.
Shao Chenwen and Liu Yani (doctoral student) are the co-first authors of the paper, and Professor Qian Yong is the corresponding author
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This work was supported and helped by Professor Yan Chao, Professor Zhu Hailiang, Professor Zhao Jin, Professor Kong Lingdong, Dr.
Chen Zhangpeng, and Dr.
Qin Yajuan from Nanjing Medical University
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The author's interview with Cell Press Cell Press specially invited Professor Qian Yong to conduct an exclusive interview on behalf of the research team, and asked him to further explain it in detail
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CellPress: The imbalance of iron homeostasis plays an important role in neurological diseases, but there is still a lack of direct imaging evidence of the distribution of active ferrous ions (Fe2+) in the living brain.
What are the difficulties here? Professor Qian Yong: The current challenges for direct imaging of the distribution of ferrous ions in the living brain mainly include the following aspects: First of all, for the living body, it needs to cross the blood-brain barrier non-traumatically to deliver the imaging agent to the brain.
It can be said that the permeability of the blood-brain barrier is a prerequisite for the development of imaging agents that target the brain in vivo; the second is biocompatibility, which needs to reduce the toxic and side effects of the detection method; the third is the temporal and spatial resolution, whether it has deep tissue penetration , Stability is also a necessary condition for long-term tracing in organisms; the fourth is sensitivity and response rate.
Active Fe2+ is unstable, and real-time detection is needed to see its every move
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CellPress: What are the characteristics of the near-infrared excited two-photon fluorescent probe (FeP) developed in this research, so that it can be used for in vivo Fe2+ brain imaging
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Professor Qian Yong: The FeP developed by us has the following characteristics: First, it has excellent blood-brain barrier permeability, which can quickly and effectively penetrate the blood-brain barrier to reach the brain; second, it has two-photon near-infrared excitation And the spectral range of the emission wavelength ensures that it can effectively show bright fluorescence through brain tissue, and avoids the interference of autofluorescence of organisms; third, it has excellent selectivity, sensitivity and light stability, etc.
, the above Some main features make it very suitable for in vivo brain imaging
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CellPress: What is the difference between the Fe2+ content in the brains of epileptic mice and normal mice? Professor Qian Yong: We first observed that the total iron content in epileptic mice was significantly higher than that in normal mice through inductively coupled plasma mass spectrometry (ICP-MS) measurement research
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When we used the probe FeP to perform imaging studies on brain tissue homogenates, live mice, isolated brains, and brain tissue slices, we found that the fluorescence intensity in epileptic mouse samples was significantly higher than that in normal mouse samples.
This result It shows that the content of active Fe2+ in the brain of epileptic mice is abnormally higher than that of normal mice
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CellPress: How does dihydroartemisinin (DHA) exert its anti-epileptic effects by regulating iron homeostasis? Professor Qian Yong: Through research on animal behavior and EEG monitoring in epilepsy model mice, we have found that DHA has potential regulatory and therapeutic effects on epilepsy mice
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In preliminary studies, we have observed that DHA can significantly improve the abnormal accumulation of Fe2+ and lipid peroxides in neurons under KA-induced stress.
We speculate that DHA may act by regulating the iron homeostasis in the brain of epileptic mice and related pathways.
Anti-epileptic effect
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Through subsequent series of molecular mechanism studies, we found that the expression of a ferroporter LCN2 was significantly increased in the brains of epilepsy model mice.
It is a neurotoxic factor secreted by reactive astrocytes and can selectively promote neurons Died, but the expression of LCN2 in the DHA pretreatment group was significantly suppressed, revealing that DHA may play an important role in brain iron homeostasis and neuronal damage in epileptic mice by regulating LCN2 secreted by reactive astrocytes Role
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In addition, we also found that DHA can up-regulate the expression level of GPX-4 protein, down-regulate the expression of Ac-p53 and TfR1, and reduce ferritin content, thereby alleviating neuronal iron death
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It should be pointed out that this study has only initially observed the potential regulatory effects of DHA in mouse models.
It needs to be further improved as to whether DHA can play an anti-epileptic effect by regulating iron homeostasis in the brain and its specific signaling pathways.
In-depth research to confirm
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CellPress: What kind of help can the results of this study provide for the evaluation of Fe2+ status in the brains of living epilepsy mice and the treatment of epilepsy? Professor Qian Yong: We rationally used the constructed fluorescent sensing tool FeP probe to perform three-dimensional two-photon brain imaging of epileptic mice, and directly observed the dynamic changes of Fe2+ content in the mouse brain during the development of epilepsy.
This is the first 3D brain imaging monitoring The dynamic distribution of Fe2+ in the brain of a neurological disease model mouse provides a research platform
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In addition, we used FeP probes for high-throughput screening of chemical regulators, and found that DHA may be a potential small molecule candidate for the treatment of epilepsy, which also provides a new research method platform for the screening of iron death regulators
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The research work also further reveals the connection between epilepsy disease and the iron death mechanism of nerve cells, which may be helpful to further advance the discovery of new chemical entities for the treatment of epilepsy disease
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CellPress: What is the focus of your next work? Professor Qian Yong: We are currently focusing on the research and development of key enzyme probes related to the lipid metabolism of nerve cells.
By optimizing the structure of the probe, improving the penetration rate of the blood-brain barrier and the signal-to-noise ratio of the probe, using chemical biology Methods to explore the temporal and spatial distribution and functional activity regulation of these key proteins
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We also plan to modify the structure of these natural products that can regulate neurodegenerative diseases discovered through probe screening, and use proteomics and other omics technologies to conduct in-depth research on related signal pathways and mechanisms for disease prevention and treatment.
Excavate new targets
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About the author Qian Yong Professor Dr.
Qian Yong, professor of Nanjing Normal University School of Chemistry and Materials Science, doctoral supervisor, distinguished professor of Jiangsu Province, Humboldt Scholar in Germany
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Long-term commitment to the detection imaging and functional regulation of key biomolecules in the brain stress process.
The research results have been published in PNAS, Nature.
Commun.
, Angew.
Chem.
Int.
Ed.
, Cell Chem.
Biol.
, Adv.
Sci.
and other journals And obtained a number of national invention patent authorizations
.

https://orcid.
org/0000-0003-3788-3575http://hky.
njnu.
edu.
cn/info/1186/5723.
htm Dr.
Chenwen Shao Dr.
Chenwen Shao, Ph.
D.
from Nanjing University
.

During the Ph.
D.
period, he focused on the research on "visual diagnosis of neurodegenerative diseases and the development of lead compounds for interventions and their mechanism of action", as the first and co-first author in PNAS, Cell Chem.
Biol.
, Adv.
Sci.
, Anal .
Chem.
, Eur.
J.
Med.
Chem.
and other international academic journals published 8 SCI papers
.

Yani Liu Yani Liu is a doctoral student at Nanjing University
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The main research direction is the development of new biosensors to reveal the mechanism of organelle interaction
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The research results of related paper information are published in the Cell Chemical Biology journal under Cell Press.
Click "Read Full Text" or scan the QR code below to view the paper
.

▌Paper title: 3D two-photon brain imaging reveals dihydroartemisinin exerts antiepileptic effects by modulating iron homeostasis▌Paper URL: https:// ▌DOI: https://doi.
org/10.
1016/j.
chembiol.
2021.
12.
006 Long press the picture to identify the QR code to read the original text.
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