The brain is the body's command center, which governs human life activities. But in fact, there is still a "second brain" in the human body, that is, the intestines.
The intestines are more than just a delicate digestive system. Existing scientific studies have shown that nerve cells can interact with the intestines, but how they interact with each other, how signals are transmitted from one tissue to another, and Systematic regulation of the body's overall metabolic level and aging process has always been an unsolved mystery.
Recently, the research team of the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences, Tian Hao Research Group, and Andrew Dillin, a professor at the University of California, Berkeley, published a paper online in the journal Cell, revealing a mitochondria from nerve cells to intestinal cells. Stress response signaling pathway.
Who is the "signal soldier"?
Researchers focus their research on the mitochondria. This little thing is not only the center of cellular energy supply, but also one of the important organelles that regulate the aging process and affect neurodegenerative diseases.
Mitochondria are very "smart", and scientists have discovered that when they are functionally damaged by external stimuli, they initiate a mitochondrial unfolded protein response that reestablishes homeostasis.
This reaction is related to important physiological processes such as natural immunity, stem cell maintenance, and life regulation of the organism.
Interestingly, in a multicellular body, this reaction can also be transmitted between different tissues, such as from nerve cells to intestinal cells, and the system regulates the metabolic level of the entire organism to cope with the damage.
Dillin believes that there is a substance in which it acts as a "signal soldier." But who is this "signal soldier", how does it "deliver the letter" to the remote organization? Little is known about this.
In some previous studies, Dillin and a team at Peking University have proposed a number of candidate substances, but they are not sufficient to cause stress in distant tissues.
"In order to observe the transmission of information, we must first give nerve cells a certain stimulation, so that it has the necessary information to transmit information." Tian Hao research group used the beauty nematode as a model to introduce a chorea pathogenic protein into its nerve cells. It stimulates mitochondrial damage in nerve cells, which in turn induces mitochondrial unfolded protein responses in the gut.
Through genetic screening methods, Tian Hao and others have made new discoveries.
New features of "Old Road"
Tian et al. found that a Wnt signaling pathway, both in invertebrates and vertebrates, is the key to accomplishing this process.
Wnt is a secreted morphogen that plays an important role in animal development.
This signaling pathway is highly conserved during species evolution, determines cell fate, and is involved in regulating tissue homeostasis and cancer development. "If this pathway is abnormal, it will lead to nervous system development problems and intestinal cancer." Tian said.
The results also found that transcellular regulation of distal tissues produces a non-autonomous mitochondrial stress response, and is inseparable from the involvement of the vesicle transport complex Retromer and serotonin.
Some clinical data show that many people with neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease have more or less diseases such as metabolic diseases and intestinal inflammation.
Therefore, this outcome may provide new therapeutic ideas for the treatment of neurodegenerative diseases and the accompanying symptoms of metabolic disorders.
"The question of whether metabolism and intestinal problems are caused by diseases of the nervous system is still inconclusive." Tian said, "But we believe that they are related, which is why we want to do related research."
Cai Shiqing, a researcher at the Institute of Neuroscience of the Chinese Academy of Sciences, said in a review article: "The Wnt signaling pathway is a well-researched 'old pathway'. This work discovered the new function of the 'old pathway' and they found neurons. - a key molecule for signaling between intestinal tissues."
"The mitochondrial unfolded protein response signal regulates animal lifespan, so their work is also important to understand how tissue aging affects animal life. The mechanism of brain and intestinal function regulation is currently the frontier of neurobiology, and this study is also brain The gut axis mechanism provides a new understanding." Cai Shiqing commented.
Tian Wei revealed that because humans also have a conservative Wnt signaling pathway, they next plan to explore the signaling processes of different tissues, especially the nervous system to the intestine, in higher animals.
Source: Chinese Journal of Science
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