I can see the status bar

Chapter 741 AQP4 protein
When discussing the disease itself, Sun Lien could at least get in the way.But when the discussion deepened to the pathogenic mechanism and special channel proteins, Sun Lien's eyes were completely darkened, and he was completely confused.

Fortunately, Yuan Ping'an also included some explanations when he described it, which at least allowed Sun Lien to sit firmly in his seat, instead of hastily turning on his phone and searching for various keywords.

The full name of AQP4 protein is "aquaporin 4" (aquaporin 4, AQP4), which is one of the important water channel proteins in the central nervous system, except for a few neurons in the hippocampus, supraoptic nucleus and paraventricular nucleus. In addition to distribution, it is mainly expressed in astrocytes and ependymal epithelial cells.

Astrocytes are interstitial cells of the nervous system, while ependymal epithelial cells are located on the surface of the central canal wall of the ventricle and spinal cord, and participate in the formation of choroidal tissue.

In addition to participating in the regulation of water metabolism balance in the central nervous system such as cerebrospinal fluid absorption, secretion and absorption, AQP4 protein can also affect the migration of astrocytes and the healing of glial scars; affect the transmission of nerve signals; Reuptake of K+ and glutamate; altering the release of neurotransmitters; participating in the formation of synapses and gap junctions, etc.Judging from the current research results, AQP4 protein is not only a key factor affecting the water and electrolyte balance in the central nervous system, but also one of the important molecular bases that determine the structure and function of astrocytes.

In 1998, Agre discovered aquaporin 1 (AQP1) on human erythrocytes, and after winning the 2003 Nobel Prize in Chemistry for this, the members of the AQP family were discovered one by one.This is a prelude to the human study of the molecular mechanism of water molecules passing through the phospholipid bilayer of the cell membrane, as well as the in-depth study of the structure and function of the AQP family.Judging from the AQP family proteins discovered so far, there are two categories of classification models.One is that all AQP proteins can be classified as water-specific and non-specific according to their operational properties.The other is divided into mercury-sensitive and mercury-insensitive according to whether its permeability can be inhibited by Hg2+.

AQP4 is the only highly specific aquaporin that is not sensitive to mercury among all known AQP proteins, and it is also one of the most important AQP proteins in the mammalian central nervous system.

According to the current research, AQP4 is mainly expressed in astrocytes, and it is in a state of polar distribution.The expression of AQP4 on the footplate side of microvessels was about ten times that of the non-footplate side.

This unique high-specificity aquaporin usually exerts biological effects in the form of a tetramer. Its permeability to water is three to four times that of other AQP proteins. Its main physiological function is to mediate water molecules across organisms. The membrane operates to maintain fluid and osmotic pressure balance and to regulate the formation of cerebrospinal fluid.In terms of pathology, it is mainly involved in the formation and elimination of cerebral edema.

The idea proposed by Yuan Ping'an is a bold inference based on the pathological effects and polarity distribution of AQP4.

"AQP4 is not generally highly expressed in the brain, and the content of AQP4 cells on astrocytes and ependymal endothelial cells is significantly higher than that in other regions." Yuan Pingan explained the reason for his inference. "Except for some expression on nerve cells in the hippocampus, supraoptic nucleus and paraventricular nucleus, there is no or low expression of AQP4 in nerve cells in other regions."

Yuan Ping'an had already explained this research result before, but Sun Li'en suddenly remembered something, grabbed a bound case book from the stool beside him and began to read it.Soon, he found what he wanted to see in it - Tang Min's intracranial low-signal area indeed included the hippocampus, supraoptic nucleus and paraventricular nucleus.It's just because the area covered by the low-signal area is too large, so they didn't notice it at first.

This assumption seems to be a little more reliable all of a sudden.

"Moreover, the AQP4 protein can also affect the migration of astrocytes, thereby affecting the speed of brain repair." Yuan Pingan continued, "Maybe this can explain why Tang Min developed more serious symptoms after undergoing a biopsy. sequelae."

Tang Min received two biopsies from the frontal lobe, and the frontal lobe plays an important role in processing primary movements.Sun Li'en has never diverted his thinking here, and even now he feels that the inability to move his feet is a common sequela of the frontal lobe puncture and biopsy.

"You just said that AQP4 protein affects the production and absorption of cerebrospinal fluid?" Sun Lien thought about this, and suddenly grasped an important point. He looked up at Yuan Ping'an and said, "Tang Min has undergone lateral ventricle drainage, and at the same time, he also has cerebellum Tonsil hernia. This shows that she must have had stubborn and severe hydrocephalus before—could it also be because of a problem with the AQP4 protein?"

"This possibility cannot be ruled out, and it can even be said that the possibility is very high." Yuan Ping'an nodded enthusiastically, "The AQP4 protein itself is of great significance to hydrocephalus, and the intractable spontaneous hydrocephalus whose cause cannot be clearly identified , it is indeed possible that there is something wrong with the patient's AQP4 protein."

After two days, Tang Min's diagnosis finally had a seemingly reliable development direction.This sudden progress made Sun Li'en even tremblingly excited.Imaging evidence, biopsy sequelae and hydrocephalus all received a unified explanation, which made Yuan Ping'an's hypothesis stand on the same starting line as the previous three guesses.They can all explain Tang Min's condition, which means that the problems related to AQP4 protein have at least the value of being verified at this moment.

After listening to the conversation between Sun Lien and Yuan Ping'an, Professor Zhang Zhifu asked after a thoughtful silence for a while, "So, what's wrong with her AQP4 protein?"

This question hits the air like a hammer.Yuan Ping'an and Sun Li'en looked at me and I looked at you, and shook their heads together after a long time, "This...we don't know either."

AQP4 protein is a specific water channel protein, which can quickly mediate water molecules in and out of cells.But neither Sun Li'en nor Yuan Ping'an knew what happened to this protein to cause Tang Min's current symptoms.

The status bar indicates that it is not so microscopic, and in the existing literature, there seems to be no precedent for AQP4 protein causing disease.

"Or there is another possibility..." Professor Zhang Zhifu continued, "AQP4 protein itself is not the direct cause of her illness, it is just affecting the real pathogenic factor in some way."

This assumption is much broader.Sun Lien knew nothing about this, while Yuan Pingan, who knew a little more, scratched his head, "AQP4 protein seems to be able to reduce the invasive ability of glioblastoma... It can't be glioblastoma, right? So many The space-occupying lesions in this area don't look like the result of reducing the ability to invade."

"The hypothesis is there, but your hypothesis still needs to be perfected. It takes a lot of energy and time to perfect it." Professor Zhang Zhifu seems to be very interested in Yuan Pingan's AQP4 protein theory. "However, you still have to reconsider whether to perfect this hypothesis or to prioritize solving other problems. After all, there is relatively plenty of time for research and projects, but Tang Min...she may not have so much time."

　This chapter should be the only one today... Luo has been writing since last night until now, and only then has he come up with such a short chapter.It's not because of Calvin, but because it is too laborious to search and improve the relevant information.

　　Let me tell you again, after Tang Min's story is over, I will open a separate chapter to explain the specific details of the process.And this single chapter is quite important, everyone must read it when the time comes.

　　
　
(End of this chapter)