How many times have the textbooks been rewritten this year?

Many of the classic knowledge engraved on biomedical textbooks have been refreshed many times, and those common sense you thought may need to be updated immediately
.

Sugar lovers are not cancer cells

100 years ago, the famous physiologist Dr.
Otto Warburg and his colleagues observed a phenomenon: Compared with normal cells, cancer cells consume more glucose
.

But in April of this year, a research team from the Vanderbilt University School of Medicine in the United States discovered that cancer cells are not the culprit because of the crazy consumption of glucose by tumors
.

With the help of positron emission tomography (PET) tumor imaging, the researchers found that the main consumer of glucose in the tumor is a type of immune cell called macrophages that has the strongest glucose uptake capacity and has a strong glucose metabolism activity
.

This result appears not only in kidney cancer models, but also in several other tumor models such as colorectal cancer and breast cancer.
The researchers pointed out that these findings are likely to be universal phenomena applicable to various cancer types
.

What is sugar RNA

Professor Carolyn Bertozzi, who won the "MacArthur Genius Award" at the age of 33, said: "If you believe in textbooks, RNA and glycans live in two different worlds
.

In May of this year, "Cell" published a research paper.
In this article, Professor Bertozzi and his colleagues described a surprising discovery to us: On the surface of various cells, there are a type of unknown in the past.
A new type of biomolecule-glycoRNA (glycoRNA)
.

GlycoRNA refers to a glycosylated RNA molecule, which uses a small piece of ribonucleic acid (RNA) as a scaffold with glycan attached to it
.

The researchers used chemical methods to equip many different glycans with luminescent groups, and noticed the continuous emergence of labeled glycan molecules
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Mitochondrial division does not always want to proliferate

In the textbook description, mitochondrial division mainly occurs when the number of mitochondria needs to be increased
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As cells grow and eventually divide, cells need more energy, and more mitochondria are needed to support them
.

But in May of this year, biophysicists at the Institute of Physics of the Federal Institute of Technology in Lausanne (EPFL) used ultra-high-resolution microscopes to study mitochondria and revealed two division mechanisms with completely different functions: one way of splitting makes mitochondria count.
Growth, the other is to "lighten the burden" to remove the damaged part
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The location of mitochondrial division is very particular
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This mitochondrial division behavior is likely to be applicable to various mammalian cells
.

The smell of birds is better

For a long time, people have generally held the idea that birds have keen sense of sight and hearing, and even the mysterious sixth sense "magnetism"; in contrast, smell is not important, and most birds have a sense of smell.
Very slow
.

The rewriting of this textbook originally came from the careful observation of a primary school student.
He noticed that European white storks often appeared in the mowing fields and found their favorite insects in the low grass
.
He posed a question to scientists at the Max Planck Institute for Animal Behavior in Germany: How does the white stork know where the field is mowing?

In order to solve the confusion of elementary school students, the researchers sprayed three grass-flavored chemicals on fields that have not been mowed recently
.
Although there was no sound of lawn mowers and no sight of mowing, birds flocked from far away
.
The results of the experiment clearly show that these birds rely solely on their sense of smell to make their foraging decisions
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Not only the European white stork, but other birds may also respond to the smell of plants when they are "injured"
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For example, a Czech biologist described in a paper published last year that after the needles of Scots pine are gnawed by pine sawfly larvae, the volatile chemicals released from the wound will attract big tits and blue tits to look for caterpillars
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Red blood cells can not only transport oxygen

The deepest impression many people learn about red blood cells from textbooks is that they circulate in the body and are responsible for delivering essential oxygen to the whole body
.
However, a study in "Science-Translational Medicine" in October this year found that red blood cells have more tasks than we thought in the past, and they actually play an important role in the immune system
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In addition to carrying oxygen, red blood cells also carry DNA fragments from other cells, such as DNA from bacteria or parasites, which directly report to the immune system
.
In patients with sepsis, more than 40% of red blood cells express a protein called TLR9 on the surface
.
This receptor protein is often associated with inflammation and can activate the immune response
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Through TLR9 on the surface, red blood cells can bind DNA from bacteria and malaria parasites, as well as mitochondrial DNA released after cell damage
.
As the combined DNA increases, the structure and morphology of red blood cells will change significantly
.
These unrecognizable red blood cells are like sentinels, which can cause the immune system to alert and cause immune cells called macrophages to come quickly
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Patients with more mitochondrial DNA bound to red blood cells tend to have higher anemia and disease severity
.
In addition to the development of new therapies for patients with acute inflammatory anemia, this new discovery on red blood cells may also provide new ideas for diagnosis
.

Cancer cells don’t just hide

We may often see textbooks describing the concealment techniques of cancer cells, how they cleverly escape the pursuit of immune cells, and finally lurking and growing slowly
.
However, a study in "Nature-Nanotechnology" completely subverted some previous assumptions.
Cancer cells not only hide, but also actively invade immune cells.
It is not as "counseling" as we imagined, but this behavior is too hidden.
It has never been discovered before
.

▲There is a nano-scale pipeline between cancer cells and T cells (picture source: reference [3])

Researchers at Brigham and Women’s Hospital in the United States placed breast cancer cells and immune cells obtained from mice in a petri dish.
After 16 hours, these cells were placed under a field emission scanning electron microscope for observation.
A cancer cell will form a nanotube with a T cell, and the width of each nanotube is about 50-2000 nanometers
.

They can see under the microscope with their own eyes by fluorescent staining that the cancer cells will continue to ingest the mitochondria of T cells into their bodies
.
In addition to robbing mitochondria, cancer cells have to consume the surrounding oxygen frantically
.
Compared with the case where cells are separated from each other, if nanotubes are present, the oxygen consumption of cancer cells will double and the growth rate will become faster
.

This may indicate that the stolen mitochondria may continue to provide energy for the growth of cancer cells
.

Reference materials:

[1] LK METTHEW LAM et al.
, (2021) DNAbinding to TLR9 expressed by red blood cells promotes innate immune activationand anemia.
SCIENCE TRANSLATIONAL MEDICINE• DOI:10.
1126/scitranslmed.
abj1008

[2] Martin Wikelski et al.
, (2021) Smell of green leaf volatiles attracts white storks to freshly cut meadows.
ScientificReports https://doi.
org/10.
1038/s41598-021-92073-7

[3] Tatjana Kleele et al.
, (2021) Distinct fission signatures predict mitochondrial degradation or biogenesis.
Nature.
Doi: https://doi.
org/10.
1038/s41586-021-03510-6

[4] Ke Xu et al.
, (2021) Glycolysis fuels phosphoinositide 3-kinase signaling to bolster T cell immunity.
Science.
DOI: 10.
1126/science.
abb2683

[5] Hae Jang, Intercellular nanotubes mediate mitochondrial trafficking between cancer and immune cells, Nature Nanotechnology (2021).
DOI: 10.
1038/s41565-021-01000-4.