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Comment by Dr. Krishna Kumari Challa on January 5, 2022 at 9:33am

When we eat, energy-rich fats and glucose enter the bloodstream. Insulin normally shuttles these nutrients to cells in muscles and fat tissue, where they are either used immediately or stored for later use. In people with insulin resistance, glucose is not efficiently removed from the blood, and higher lipolysis increases the fatty acid levels. These extra fatty acids accelerate glucose production from the liver, compounding the already high glucose levels. Moreover, fatty acids accumulate in organs, exacerbating the insulin resistance—characteristics of diabetes and obesity.

Previously, the lab showed that injecting FGF1 dramatically lowered blood glucose in mice and that chronic FGF1 treatment relieved insulin resistance. But how it worked remained a mystery.

In the current work, the team investigated the mechanisms behind these phenomena and how they were linked. First, they showed that FGF1 suppresses lipolysis, as insulin does. Then they showed that FGF1 regulates the production of glucose in the liver, as insulin does. These similarities led the group to wonder if FGF1 and insulin use the same signaling (communication) pathways to regulate blood glucose.

It was already known that insulin suppresses lipolysis through PDE3B, an enzyme that initiates a signaling pathway, so the team tested a full array of similar enzymes, with PDE3B at the top of their list. They were surprised to find that FGF1 uses a different pathway—PDE4.

"This mechanism is basically a second loop, with all the advantages of a parallel pathway. In insulin resistance, insulin signaling is impaired. However, with a different signaling cascade, if one is not working, the other can. That way you still have the control of lipolysis and blood glucose regulation.

Finding the PDE4 pathway opens new opportunities for drug discovery and basic research focused on high blood glucose (hyperglycemia) and insulin resistance. The scientists are eager to investigate the possibility of modifying FGF1 to improve PDE4 activity. Another route is targeting multiple points in the signaling pathway before PDE4 is activated.

The unique ability of FGF1 to induce sustained glucose lowering in insulin-resistant diabetic mice is a promising therapeutic route for diabetic patients.

 Ronald M Evans, FGF1 and insulin control lipolysis by convergent pathways, Cell Metabolism (2022). DOI: 10.1016/j.cmet.2021.12.004. www.cell.com/cell-metabolism/f … 1550-4131(21)00623-9

https://medicalxpress.com/news/2022-01-route-blood-sugar-independen...

Comment by Dr. Krishna Kumari Challa on January 5, 2022 at 9:32am

Researchers find a new route for regulating blood sugar levels independent of insulin

The discovery of insulin 100 years ago opened a door that would lead to life and hope for millions of people with diabetes. Ever since then, insulin, produced in the pancreas, has been considered the primary means of treating conditions characterized by high blood sugar (glucose), such as diabetes. Now, scientists have discovered a second molecule, produced in fat tissue, that, like insulin, also potently and rapidly regulates blood glucose. Their finding could lead to the development of new therapies for treating diabetes, and also lays the foundation for promising new avenues in metabolism research.

The study, which was published in Cell Metabolism on January 4, 2022, shows that a hormone called FGF1 regulates blood glucose by inhibiting fat breakdown (lipolysis). Like insulin, FGF1 controls blood glucose by inhibiting lipolysis, but the two hormones do so in different ways. Importantly, this difference could enable FGF1 to be used to safely and successfully lower blood glucose in people who suffer from insulin resistance.

Finding a second hormone that suppresses lipolysis and lowers glucose is a scientific breakthrough. Scientists have identified a new player in regulating fat lipolysis that will help us understand how energy stores are managed in the body.

Part 1

Comment by Dr. Krishna Kumari Challa on January 4, 2022 at 12:18pm

Scientists reveal the genetic basis of mitochondrial diseases

Mutations in genes encoding mitochondrial aminoacyl-tRNA synthetases are linked to diverse diseases. However, the precise mechanisms by which these mutations affect mitochondrial function and disease development are not fully understood.

Wenlu Fan et al, FARS2 deficiency in Drosophila reveals the developmental delay and seizure manifested by aberrant mitochondrial tRNA metabolism, Nucleic Acids Research (2021). DOI: 10.1093/nar/gkab1187

https://phys.org/news/2022-01-scientists-reveal-genetic-basis-mitoc...

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Comment by Dr. Krishna Kumari Challa on January 4, 2022 at 12:04pm

Researchers gain insights into how ultrasmall bacteria from the environment have adapted to live inside humans

The microbes that live inside our mouths, collectively known as the oral microbiome, impact our overall health in many ways that are not yet fully understood. Some bacteria cause inflammation, leading to periodontitis and other systemic diseases, such as cardiovascular disease and diabetes. Other oral organisms have been associated with certain types of cancer. Scientists are working to understand how these microbes interact with one another and our bodies to tease out their individual roles in health and disease.

Among the diverse bacterial species living within our mouths is a group belonging to the Candidate Phyla Radiation (CPR). These bugs are especially mysterious because they are ultra-small, adopt a unique symbiotic lifestyle with their host bacteria, and most have yet to be cultured by scientists and studied in the lab. The only bacteria within the CPR to be examined in-depth are a group called TM7, which were cultivated for the first time in 2014.

Now scientists have developed a new model system using the first isolated human oral TM7 strain, TM7x, and its host bacterium, Actinomyces odontolyticus. Researchers used the model system to experimentally study these tiny bacteria, testing a hypothesis for how TM7 adapted to live inside humans, and providing empirical data to confirm previous genomic studies. Their findings were published today in the journal Proceedings of the National Academy of Sciences (PNAS).

Scientists have found TM7 in many different environments, including soil, groundwater, and the bodies of other mammals. Studies have shown that while maintaining a remarkably similar genome overall, the TM7 found in human mouths are unique from those in other environments because they have acquired a gene cluster encoding the arginine deiminase system, or ADS.

Researchers hypothesized that TM7 acquired ADS as an evolutionary advantage to help them adapt and survive in the human oral cavity. They tested this and found  found that ADS helped TM7x break down arginine, a process that produces the compounds Adenosine triphosphate (ATP) and ammonia. The increased abundance of ATP and ammonia benefitted TM7x by increasing its infectivity, or ability to multiply. It also protected TM7x and its host bacterium from acid stress, a condition that microbes frequently encounter in the human oral cavity due to the acid created when bacteria feed on and metabolize dietary carbohydrates. Ultimately, the experiments showed TM7x were able to survive in the experimental environment for longer than they could without the addition of arginine, thanks to ADS.

Earlier study: Otari Chipashvili et al, Episymbiotic Saccharibacteria suppresses gingival inflammation and bone loss in mice through host bacterial modulation, Cell Host & Microbe (2021). DOI: 10.1016/j.chom.2021.09.009

Acquisition of the arginine deiminase system benefits epiparasitic Saccharibacteria and their host bacteria in a mammalian niche environment, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2114909119.

https://phys.org/news/2022-01-gain-insights-ultrasmall-bacteria-env...

Comment by Dr. Krishna Kumari Challa on January 4, 2022 at 11:57am

One of the reasons why a clearer understanding of the channel protein's natural structure is important is to advance the development of treatments for genetic disorders for which there is no known cure, such as retinitis pigmentosa. With this disease, photoreceptors gradually die off, leaving people blind. One possible cause is that the body is unable to correctly produce the CNG channel protein due to a genetic defect. As a result, the ion channel does not close completely when light hits the eye, disrupting the cell's electrochemical balance and causing the cells to die.

If we could find molecules that affect the protein in such a way that the channel would completely close, we could prevent the cells from dying—and thus stop people going blind.

 Now that researchers have identified the precise structure of the protein they are able to search specifically for such molecules.

The protein comprises four parts: three lots of subunit A, and one lot of subunit B. A correctly functioning ion channel is only possible in this combination. In their study, PSI scientists show why the B subunit seems to play such an important role: a side arm of the protein—a single amino acid—protrudes from the rest of the protein, like a barrier across a gateway. This narrows the passage in the channel to the point where no ions can pass through.

 It is interesting to note that the additional barrier is found not only in the protein from the cow's eye, but seems to apply to all types of animal, as the scientists showed. Whether crocodiles, eagles or humans—all living creatures with an ion channel in their eye have the same protruding amino acid at this position in the protein. As it has been preserved so consistently during evolution, it must be essential for the functioning of the channel.

Diane C. A. Barret et al, The structure of the native CNGA1/CNGB1 CNG channel from bovine retinal rods, Nature Structural & Molecular Biology (2021). DOI: 10.1038/s41594-021-00700-8

https://phys.org/news/2022-01-newly-discovered-protein-rod-cells-re...

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Comment by Dr. Krishna Kumari Challa on January 4, 2022 at 11:55am

Newly-discovered protein in the rod cells of the retina helps us see in dim light

 scientists have shed light on an important component of the eye: a protein in the rod cells of the retina which helps us see in dim light. Acting as an ion channel in the cell membrane, the protein is responsible for relaying the optical signal from the eye to the brain. If a genetic disorder disrupts the molecular function in a person, they will go blind. Scientists have deciphered the protein's three-dimensional structure, preparing the way for innovative medical treatments. The study is published in the scientific journal Nature Structural & Molecular Biology.

It's thanks to the rod cells in our eye that we can observe the stars in the night sky.

These photo cells are so sensitive to light that they can detect even a single photon reaching us from a very remote part of the universe—a truly incredible feat." The ability of our brain to eventually translate these light beams into a visual impression is partly down to the cyclic nucleotide-gated (CNG) ion channels whose three-dimensional structure has now been illuminated by a  research group.

The ion channel acts as a gatekeeper controlling whether specific particles are allowed through to the interior of the receptor cell. It is embedded in the protein-rich shell—the cell membrane—of the rod cells. In darkness, the ion channel, and thus the gate to the cell, is completely open. But when light hits the eye, it triggers a cascade of processes in the rod cells. This ultimately causes the gate to close, with the result that positively charged particles, such as calcium ions, can no longer enter into the cell.

This electrochemical signal continues via the nerve cells into the brain's visual cortex, where a visual impression—such as a flash of light—is created. The scientists  used cryo-electron microscopy to reveal the three-dimensional structure of the ion channel.

Part 1

Comment by Dr. Krishna Kumari Challa on January 4, 2022 at 11:51am

How To Kick A Pulsar Out Of The Galaxy

The Baseline #10 - How To Kick A Pulsar Out Of The Galaxy from NRAO Outreach on Vimeo.

Comment by Dr. Krishna Kumari Challa on January 4, 2022 at 11:38am

Scientists discover emergency pathway to help human cells with protein damage survive

Cell proteins damaged by oxygen radicals can be chemically "tagged" for elimination, but an "emergency pathway" bypasses strict protocol and can eliminate even without the need for prior tagging.

An international research team headed by Technion scientists has found an alternative manner for eliminating damaged proteins when the cells are impaired by "oxygen radicals," as can happen in failing human hearts where there is poor cell respiration and cells become oxygen depleted, or suffer "hypoxia," because of poor oxygen uptake.

Significantly, the researchers discovered that there can be a shift from the tightly controlled process of eliminating proteins in the cells to a less strict mechanism when cells enter an "emergency protocol." This shift can "clear up" the toxic proteins before their toxicity levels get too high.

Human cells—both functional and damaged—are constantly recycled by chemically "tagging" and targeting for removal when they are under stress by the ubiquitin system (2004 Nobel Prize in chemistry). At the same time, a few proteins that are intact and functional can also be dragged into the 20S proteasome "molecular disposal unit" along with the toxic proteins that have be targeted for destruction. Nevertheless, rather than harm cells, this mode of action by 20S proteasome may aid cells in rapidly remove toxic proteins. In their conclusion, the authors raised the interesting speculation that this emergency pathway can help even damaged cells to withstand bouts of stress and allow them to "age gracefully."

Indrajit Sahu et al, The 20S as a stand-alone proteasome in cells can degrade the ubiquitin tag, Nature Communications (2021). DOI: 10.1038/s41467-021-26427-0

https://phys.org/news/2022-01-scientists-emergency-pathway-human-ce...

Comment by Dr. Krishna Kumari Challa on January 4, 2022 at 11:34am

Over the course of evolution, some species have developed powerful means of suppressing cancer. Generally, they do this either by trying to prevent mutations from arising in the first place, improving the fidelity of DNA copying mechanisms or by repairing damaged DNA, or some combination of these.

Often, crucial cancer-related genes come into play. One of these, a tumor-suppressing gene known as TP53, can act to repair damaged DNA. Where the sequence can not be repaired, the gene instructs the cell to undergo apoptosis or cell death, preventing the mutation from being duplicated in subsequent cell generations. Elephants, which would otherwise be highly cancer prone due to their size and longevity, carry multiple copies of TP53 and have very low rates of cancer.

Although high radiation caused catastrophic damage to T. adhaerens' DNA, the animal's powers of DNA repair enabled the organism to recover from the assault. Although not all individuals survived the highest doses of radiation, those that did were able to repopulate the culture after 30 days of exposure to 218.6 Gy. A total of 74 genes were significantly overexpressed in T. adhaerens following radiation exposure.

Through a combination of aggressive DNA repair and ejection of damaged cells, T. adhaerens engage in continual bodily renewal, keeping them cancer-free. Understanding such mechanisms may spur new methods of preventing and treating the disease in humans. Other, as -yet-to be discovered genes likely play a role in T. adhaerens' remarkable resistance to cancer, making this tiny creature a treasure chest of information.

 Angelo Fortunato et al, Upregulation of DNA repair genes and cell extrusion underpin the remarkable radiation resistance of Trichoplax adhaerens, PLOS Biology (2021). DOI: 10.1371/journal.pbio.3001471

https://phys.org/news/2022-01-microorganism-cancer-resistance.html?...

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Part 2

Comment by Dr. Krishna Kumari Challa on January 4, 2022 at 11:32am

Microorganism sheds new light on cancer resistance

A simple, marine-dwelling creature known as Trichoplax adhaerens has some remarkable properties. The organism can tolerate unusually high doses of radiation that would kill most other forms of life. T. adhaerens has another intriguing characteristic: the ability to resist cancer.

In a new study scientists found  T. adhaerens' unusual behavior, including its capacity to repair its DNA even after significant radiation damage and to extrude injured cells, which later die.

The findings advance scientific investigations of natural cancer-suppression mechanisms across life. Insights gleaned from these evolutionary adaptations may find their way into new and more effective therapies for this leading killer.

The unusual microorganism observed in the new study is rudimentary in form and easily cultured in the lab. This makes T. adhaerens an attractive model organism, enabling researchers to home in on fundamental processes of radiation tolerance as well as the underlying mechanisms guiding DNA repair, programmed cell death and other natural means of cancer resistance.

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