PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

Squishy white blood cells quickly become highly stiff and viscous in response to a threat

2021-03-16
(Press-News.org) Like a well-trained soldier, a white blood cell uses specialized abilities to identify and ultimately destroy dangerous intruders, including creating a protrusion to effectively reach out, lock-on, probe, and possibly attack its prey. Researchers reporting March 16 in Biophysical Journal show in detail that these cells take seconds to morph into these highly rigid and viscous defensive units.

Senior author Julien Husson (@_julienhusson), a biophysicist at École Polytechnique near Paris, and collaborators showed previously that certain white blood cells, called T cells, can push and pull perceived threats via specialized connections. To exert such forces, a cell must reorganize its internal structure, making itself more rigid. In the current study, Husson's team devised a micropipette rheometer to measure the rigidity, along with the viscosity, of a white blood cell during its transformation. The researchers' goal was to quantify the physical changes that arise in a white blood cell as it pushes or pulls on a foreign body--in this case, a bead coated with chemicals to attract the cell.

"We knew that when forming and using its protrusion, the cell was strongly reorganizing its cytoskeleton and that this cytoskeleton is a big player in giving a cell its mechanical properties," says Husson. "So, I believed there should be some signature mechanical trace."

Stiffness is a measure of how much a material deforms when under a certain amount of pressure, whereas viscosity refers to how fast the material deforms under this pressure. Therefore, to simultaneously measure these properties of a white blood cell while instigating the cell's immune response, the team needed an experimental setup that could somehow both maintain and vary the force on the cell while also causing it to respond as if it come upon a threat.

The researchers' solution was to apply a force that carefully oscillated around a constant, average value. The cell's stiffness was calculated from the tiny deformation induced by the oscillations, and the viscosity was calculated from the delay between an oscillation and resulting deformation. At the same time, the object applying the force was a bead coated with antibodies, which caused the cell to activate, change shape, and latch onto the bead.

"Despite expecting some mechanical changes, what we found was surprisingly dramatic," says Husson. The team looked at three types of white blood cells and discovered that in all cases, "the cells' stiffnesses and viscosities begin changing within seconds of coming into contact with the beads and increase up to ten times within minutes."

"Intriguingly," Husson says, "the mechanical changes begin even before any shape changes," evoking the question of whether these significant changes to white blood cells' mechanical properties are simply consequences of other functions or have their own utility.

The answer to this question could lie in another result of the study: Husson and colleagues found that a cell's stiffness and viscosity change together, at a fixed ratio that is unique to the cell type, like a mechanical fingerprint. "It was really exciting to know that there was this kind of universality," he says.

Altogether, the paper's results suggest an underlying physical mechanism that could apply broadly across cell types and lead to new models, theories, and ultimately a better understanding and control of our cells, in our immune system and beyond.

INFORMATION:

This work was primarily funded by the French National Research Agency, CNRS, École Polytechnique, and the AXA Research Fund.

Biophysical Journal, Zak et al.: "Rapid viscoelastic changes are a hallmark of early leukocyte activation" https://www.cell.com/biophysj/fulltext/S0006-3495(21)00200-9

Biophysical Journal (@BiophysJ), published by Cell Press for the Biophysical Society, is a bimonthly journal that publishes original research and reviews on the most important developments in modern biophysics--a broad and rapidly advancing field encompassing the study of biological structures and focusing on mechanisms at the molecular, cellular, and systems levels through the concepts and methods of physics, chemistry, mathematics, engineering, and computational science. Visit: http://www.cell.com/biophysj/home. To receive Cell Press media alerts, contact press@cell.com.



ELSE PRESS RELEASES FROM THIS DATE:

Brain disease research reveals differences between sexes

Brain disease research reveals differences between sexes
2021-03-16
WASHINGTON, March 16, 2021 -- Men and women are impacted differently by brain diseases, like Alzheimer's disease and Parkinson's disease. Researchers are urging their colleagues to remember those differences when researching treatments and cures. In APL Bioengineering, by AIP Publishing, University of Maryland scientists highlight a growing body of research suggesting sex differences play roles in how patients respond to brain diseases, as well as multiple sclerosis, motor neuron disease, and other brain ailments. That is progress from just a few years ago, said Alisa Morss ...

Tear glands in a dish can cry

2021-03-16
Stem-cell-derived organoids that swell up with tears could shed light on the biology of crying and dry-eye disease, suggests a study publishing March 16 in the journal Cell Stem Cell. Although regenerative therapies using human tear-gland organoids will not be possible anytime soon, these researchers have demonstrated that the organoids can engraft, integrate, and produce mature tear products upon transplantation into mouse tear glands. "We hope that scientists will use our model to identify new treatment options for patients with tear-gland disorders by either testing new drugs on a patient's organoids or expanding healthy cells and, one day, using them for transplantation," says senior study author Hans Clevers (@HansClevers) of the Hubrecht Institute. The ...

Second-wave COVID mortality dropped markedly in (most) wealthier zones

Second-wave COVID mortality dropped markedly in (most) wealthier zones
2021-03-16
Wealthier northeastern US states and Western European countries tended to have significantly lower mortality rates during second-wave COVID-19 infections, new research from the University of Sydney and Tsinghua University has shown. However, the pattern was not as general as expected, with notable exceptions to this trend in Sweden and Germany. Researchers say mortality change could have several explanations: European first-wave case counts were underestimated; First-wave deaths disproportionately affected the elderly; Second-wave infections tended to affect younger people; With some ...

Machine learning can identify cancerous cells by their acidity

Machine learning can identify cancerous cells by their acidity
2021-03-16
WASHINGTON, March 16, 2021 -- Cancerous cells exhibit several key differences from healthy cells that help identify them as dangerous. For instance, the pH -- the level of acidity -- within a cancerous cell is not the same as the pH within a healthy cell. Researchers from the National University of Singapore developed a method of using machine learning to determine whether a single cell is cancerous by detecting its pH. They describe their work in the journal APL Bioengineering, from AIP Publishing. "The ability to identify single cells has acquired a paramount importance in the field of precision and personalized medicine," ...

Seroprevalence of SARS-CoV-2 antibodies in US adult asymptomatic population

2021-03-16
What The Study Did: The findings of this study suggest that, based on a sample from an otherwise healthy population, the overall number of SARS-CoV-2 infections in the U.S. may be substantially higher than estimates based on public health case reporting. Authors: Robert L. Stout, Ph.D., of Clinical Reference Laboratory Inc. in Lenexa, Kansas, is the corresponding author. To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/ (doi:10.1001/jamanetworkopen.2021.1552) Editor's Note: The article includes conflict of interest and funding/support disclosures. Please see the article for additional information, including other authors, author contributions and affiliations, ...

Nursing home characteristics associated with resident COVID-19 morbidity in communities with high infection rates

2021-03-16
What The Study Did: Researchers examined nursing homes in communities with the highest COVID-19 prevalence to identify characteristics associated with resident infection rates. Authors: Hye-Young Jung, Ph.D., of Weill Cornell Medical College in New York, is the corresponding author. To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/ (doi:10.1001/jamanetworkopen.2021.1555) Editor's Note: The article includes funding/support disclosures. Please see the article for additional information, including ...

Viruses adapt to 'language of human cells' to hijack protein synthesis

Viruses adapt to language of human cells to hijack protein synthesis
2021-03-16
The first systematic study of its kind describes how human viruses including SARS-CoV-2 are better adapted to infecting certain types of tissues based on their ability to hijack cellular machinery and protein synthesis. Carried out by researchers at the Centre for Genomic Regulation (CRG), the findings could help the design of more effective antiviral treatments, gene therapies and vaccines. The study is published today in the journal Cell Reports. Living organisms make proteins inside their cells. Each protein consists of single units of amino acids which are stitched together according to instructions encoded within DNA. The basic units of these instructions are known as a codons, each of which corresponds ...

Embryonic tissue undergoes phase transition

2021-03-16
When scientists at the Institute of Science and Technology (IST) Austria looked at developing zebrafish embryos, they observed an abrupt and dramatic change: within just a few minutes, the solid-like embryonic tissue becomes fluid-like. What could cause this change and, what is its role in the further development of the embryo? In a multidisciplinary study published in the journal Cell, they found answers that could change how we look at key processes in development and disease, such as tumor metastasis. To learn more about how a tiny bunch of cells develops into complex systems ...

Study: One enzyme dictates cells' response to a probable carcinogen

2021-03-16
CAMBRIDGE, MA -- In the past few years, several medications have been found to be contaminated with NDMA, a probable carcinogen. This chemical, which has also been found at Superfund sites and in some cases has spread to drinking water supplies, causes DNA damage that can lead to cancer. MIT researchers have now discovered a mechanism that helps explain whether this damage will lead to cancer in mice: The key is the way cellular DNA repair systems respond. The team found that too little activity of one enzyme necessary for DNA repair leads to much higher cancer rates, while too much activity can produce tissue damage, especially in the liver, which can be fatal. Activity ...

Much of Mars' ancient water was buried in the planet's crust, not lost to space

2021-03-16
Several oceans' worth of ancient water may reside in minerals buried below Mars' surface, report researchers. The new study, based on observational data and modeling, shows that much of the red planet's initial water - up to 99% - was lost to irreversible crustal hydration, not escape to space. The findings help resolve the apparent contradictions between predicted atmospheric loss rates, the deuterium to hydrogen ratio (D/H) of present-day Mars and the geological estimates of how much water once covered the Martian surface. Ancient Mars was a wet planet - dry riverbeds and relic shorelines record a time when vast volumes of liquid water flowed across the surface. Today, ...

LAST 30 PRESS RELEASES:

Older teens who start vaping post-high school risk rapid progress to frequent use

Corpse flowers are threatened by spotty recordkeeping

Riding the AI wave toward rapid, precise ocean simulations

Are lifetimes of big appliances really shrinking?

Pink skies

Monkeys are world’s best yodellers - new research

Key differences between visual- and memory-led Alzheimer’s discovered

% weight loss targets in obesity management – is this the wrong objective?

An app can change how you see yourself at work

NYC speed cameras take six months to change driver behavior, effects vary by neighborhood, new study reveals

New research shows that propaganda is on the rise in China

Even the richest Americans face shorter lifespans than their European counterparts, study finds

Novel genes linked to rare childhood diarrhea

New computer model reveals how Bronze Age Scandinavians could have crossed the sea

Novel point-of-care technology delivers accurate HIV results in minutes

Researchers reveal key brain differences to explain why Ritalin helps improve focus in some more than others

Study finds nearly five-fold increase in hospitalizations for common cause of stroke

Study reveals how alcohol abuse damages cognition

Medicinal cannabis is linked to long-term benefits in health-related quality of life

Microplastics detected in cat placentas and fetuses during early pregnancy

Ancient amphibians as big as alligators died in mass mortality event in Triassic Wyoming

Scientists uncover the first clear evidence of air sacs in the fossilized bones of alvarezsaurian dinosaurs: the "hollow bones" which help modern day birds to fly

Alcohol makes male flies sexy

TB patients globally often incur "catastrophic costs" of up to $11,329 USD, despite many countries offering free treatment, with predominant drivers of cost being hospitalization and loss of income

Study links teen girls’ screen time to sleep disruptions and depression

Scientists unveil starfish-inspired wearable tech for heart monitoring

Footprints reveal prehistoric Scottish lagoons were stomping grounds for giant Jurassic dinosaurs

AI effectively predicts dementia risk in American Indian/Alaska Native elders

First guideline on newborn screening for cystic fibrosis calls for changes in practice to improve outcomes

Existing international law can help secure peace and security in outer space, study shows

[Press-News.org] Squishy white blood cells quickly become highly stiff and viscous in response to a threat