Advancing our view at the subcellular level

Date:
February 25, 2022
Source:
University of Cincinnati
Summary:
Researchers have developed a new pH probe and imaging technique
to provide researchers more information when studying diseases
like cancer and Alzheimer's.



FULL STORY ==========================================================================
In the field of scientific research, details matter. The minutia of
processes and structures are explained with specificity, data points
are reported to the most precise decimal and seeing is believing.


==========================================================================
Now, University of Cincinnati cancer biologists have developed a new piece
of technology and a new imaging technique that will help researchers
glean more detailed data points and see cells in more precise detail
when studying the development of cancer and neurodegenerative diseases.

Jiajie Diao, PhD, associate professor in the Department of Cancer Biology
in UC's College of Medicine, recently published an article detailing
the progress in the journal Advanced Healthcare Materials.

New probe Some of Diao's research focuses on a tiny part inside cells,
called a lysosome, that is involved in cell processes. A lysosome
is an "organelle," or a specialized structure that performs various
jobs inside cells. In the same way organs, such as the heart, liver,
stomach and kidneys, serve specific functions to keep an organism alive, organelles serve specific functions to keep a cell alive. Diao's research centers on the lysosomes that act as the "recycling center" within cells, helping the cell reuse broken or malfunctioning building blocks for
different purposes.

To accomplish its job, lysosomes need to be in an acidic environment
and generally have a low pH value. However, abnormal pH levels within
lysosomes have been associated with cellular malfunctions that can lead
to diseases like cancer and Alzheimer's disease.



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In order to study how pH levels can change and affect lysosomes and cells,
Diao and his team collaborated with Dojindo Laboratories and Yujie Sun,
PhD, associate professor in UC's Department of Chemistry, to develop a
new probe that attaches to the lysosomes and is specially designed to
provide more details to researchers. Diao said the resulting "EC Green"
probe is the next generation of lysosome probes and features several improvements from current industry standards.

As the name suggests, the probe is green and becomes a brighter shade
of green when the cell environment becomes more acidic. This gives
researchers more information than current probes, which do not change
colors, and can help identify correlations between changes in acidity
and cells becoming cancerous.

Diao said this unique probe enables multidimensional analysis of lysosome dynamics, including spatial, structural and pH information over time.

Many currently available probes attach within the lysosome, which Diao
said is like placing a string inside a water balloon. If the lysosome
bursts, the probe washes away and is detached from the lysosome, making
it no longer useful for tracking purposes.

In contrast, the EC Green probe is anchored to the lysosome membrane. Even
if the lysosome breaks, it stays secure in its position like a piece of
string that remains attached to the outside of a popped balloon.



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"So it will be very stable. You can put it there for several days,"
Diao said.

"The commonly used commercial probe will disappear, but our probe will
last forever because they get protected by the outer membrane." The probe
is also specially designed to emit a large number of photons so that it
can withstand super resolution imaging under high laser intensity.

"When you use a high intensity, most of the probe will get photo
bleached. When you stimulate something too hard, it will just die,"
Diao said.

While it provides a number of advantages, Diao said the most important
facet of the probe is that it is useful.

According to Diao, EC Green is relatively inexpensive and extremely quick
and easy for researchers to use. About 20-30 minutes after staining cells
with the probe, the samples can be washed and placed under a microscope
for observation.

"It's so simple and nobody would have a problem using them," he
said. "That was another concept for us when developing the new probe. We
don't want to just make everything so difficult; what we want is to make everything simpler." Diao and Sun are already hard at work collaborating
on the next generation of EC Green, which will provide even more details
into pH levels by turning from green to red in different levels of
acidity. The hope is to be ready to obtain a patent and publish another
article on this new probe by the end of 2022.

Mapping the cellular landscape In addition to the EC Green probe,
Diao and Sun have also developed a new imaging technique that allows researchers to precisely measure the distance, shape and location of
each organelle within a cell. This can help provide more information
about the interaction between organelles and how these interactions may
lead to the development of diseases.

The technique builds upon and uses superresolution microscopy, which
provides clearer images of particles at the subcellular level.

"So we measure the relative distance between organelles like lysosomes
and mitochondria," Diao said. "We found that just by simply doing a
surveying and mapping inside the cell using our superresolution, we
can achieve and discover many unknown changes inside the cell." In the
first use of the new measurement technique described in the article, the researchers found that mitochondria, the organelle in cells responsible
for energy production and respiration, become enlarged when developing
into degenerative diseases.

Lysosomes were also found to tend to move closer to mitochondria when
the mitochondria are damaged. Further research can help determine more
about how organelles' sizes and placements in relation to each other
can cause disease, Diao said.

Increasing capabilities with AI Now that the measurement imaging technique
has been developed, Diao said the team is beginning to work with computer scientists to harness the power of artificial intelligence to increase
how it can be used.

"Nowadays, lots of measurements are made by people and by a simple
algorithm, so we still need manpower," Diao said. "We are developing AI,
the machinery, the intelligence to try to do everything by the machine."
Down the road, Diao said the hope is that an algorithm can be trained
with a wide variety of images of healthy and diseased cells so that the software can analyze a cell image and then predict whether or not it
will become cancerous.

The technique combined with AI could also be used to study the
effectiveness of drugs to treat diseases, for example to see if there
are specific organelles that are contributing to a patient developing
drug resistance to a certain medication.

"This will give us a next level ability," he said. "Currently, most people
are looking at the tissue level or a higher level, but we can go down to
the subcellular level." Due to the purchase of a new microscope from the
UC College of Medicine and Department of Cancer Biology, any researcher
at the University of Cincinnati or Cincinnati Children's Hospital Medical Center is now equipped to take advantage of the innovations from Diao's
lab in future studies.

"So that's what we actually are trying, to let more people use the most advanced probe and the most advanced imaging technique to do their study,"
Diao said.

special promotion Explore the latest scientific research on sleep and
dreams in this free online course from New Scientist -- Sign_up_now_>>> ========================================================================== Story Source: Materials provided by University_of_Cincinnati. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Kangqiang Qiu, Ryo Seino, Guanqun Han, Munetaka Ishiyama,
Yuichiro Ueno,
Zhiqi Tian, Yujie Sun, Jiajie Diao. De Novo Design of A
Membrane‐Anchored Probe for Multidimensional Quantification of
Endocytic Dynamics. Advanced Healthcare Materials, 2022; 2102185
DOI: 10.1002/adhm.202102185 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/02/220225113920.htm

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