Personalized immunotherapy: Rapid screening of therapeutic combinations

An innovative testing platform that more closely mimics what cancer encounters in the body may allow for more precise, personalized therapies by enabling the rapid study of multiple therapeutic combinations against tumor cells. The platform, which uses a three-dimensional environment to more closely mirror a tumor microenvironment, is demonstrated in research published in Communications Biology.
“This whole platform really gives us a way to optimize personalized immunotherapy on a rapid, high throughput scale,” said Jonathan Dordick, Institute Professor of chemical and biological engineering and member of the Center for Biotechnology and Interdisciplinary Studies (CBIS) at Rensselaer Polytechnic Institute, who led this research. “You can imagine somebody having cancer, and you quickly biopsy the tumor and then you use this biochip platform to identify very quickly — within a day or two — what specific treatment modality might be ideally suited against a particular cancer.”
Of particular interest to researchers is the behavior of a specific type of immune cell known as natural killer (NK) cells, which seek out cancer or viruses within the body, bind to their receptors, and excrete an enzyme meant to kill the unwanted cells. The platform studied in this paper allows researchers to compare what happens when the NK cells are left to fight tumor cells on their own versus how they behave when an antibody or cancer drug, or a combination of the two, is added.
The platform is a small two-piece plastic chip that’s about the size of a microscope slide. One side of the sandwich chip contains 330 tiny pillars upon which researchers can place an external matrix, made of a gel-like substance, which mimics the mechanical environment of a tumor cell. When cancer cells are placed inside this gel-like structure, they’re encouraged to grow into a spheroid shape, much as they would inside the body. The second piece contains 330 microwells within which NK cells can be added in suspension — much as they would flow, untethered inside the body.
At Rensselaer, Dordick collaborated with Seok-Joon Kwon, senior research scientist in CBIS, and Sneha Gopal, who recently received her Ph.D. based, in part, on this study. The Rensselaer team collaborated with researchers from Konyang University and Medical & Bio Decision Company Ltd. To test this platform, researchers studied two types of breast cancer cells, as well as pancreatic cancer cells, with various combinations of NK cells, two monoclonal antibodies, and an anti-cancer chemotherapy drug.
“You can screen very quickly to determine what combinations of NK cells, antibodies, and chemotherapeutic drugs target the cancer cells within the spheroid geometry,” Dordick said. “What really is amazing is we see very significant differences between what happens in that spheroid, within the slots of the chip, versus what would happen in a more traditional two-dimensional cell culture that’s often used in the screening.”
In the spheroid design, for instance, the chemotherapy drug paclitaxel had little effect on the three types of cancer cells on its own, whereas in a traditional two-dimensional system, Dordick said, the drug may appear to do well. It performed dramatically better when it was combined with both NK cells and an antibody.
“This platform moves researchers closer to personalized medicine,” said Deepak Vashishth, director of CBIS. “This work conducted by Professor Dordick and his research group is an excellent example of how we, at Rensselaer, are providing a new angle to human health by developing new approaches at the intersection of engineering and life sciences to enhance cures for diseases such as cancer.”
To further the potential use of this tool, Dordick said that it must be tested on a wide range of cancer types, including a tumor microenvironment that consists of multiple different types of cells. In the future, he envisions that the platform has the potential to identify combination therapies that work best against a patient’s specific cancer, enabling the identification and delivery of personalized immunotherapy.

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Unlocking genetic clues behind aortic aneurysm

A new study increases knowledge of the genetics behind aortic aneurysm, a disease that can spark life-threatening events like aortic dissections and ruptures.
University of Michigan Health-led researchers compared blood samples from more than 1,300 people who had a thoracic aortic aneurysm with more than 18,000 control samples, in partnership with U-M’s Cardiovascular Health Improvement Project and its Michigan Genomics Initiative.
“After examining nearly the entire human genome for genetic changes that increase risk of aneurysm, we discovered a new change in the genetic code of a transcription factor, which means it controls many other genes,” explained co-corresponding author Cristen Willer, Ph.D., a professor of cardiovascular medicine, internal medicine, human genetics and computational medicine and bioinformatics at University of Michigan Health.
Then, Willer’s team collaborated with Minerva Garcia-Barrio, Ph.D., an assistant professor of internal medicine, to examine the role this gene played in smooth muscle cells, a component of aorta.
“We examined this gene in human cells and discovered that the transcription factor we identified is a key factor that gives instructions to cells about when to die and replenish,” said co-lead author Tanmoy Roychowdhury, Ph.D., a research fellow in the Division of Cardiovascular Medicine.
The authors say future research might investigate whether slowing down this apoptosis, or cellular death, in aortic aneurysm could reduce the risk of a person experiencing an aortic dissection or rupture in the future.
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Materials provided by Michigan Medicine – University of Michigan. Original written by Haley Otman. Note: Content may be edited for style and length.

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New approach eradicates breast cancer in mice

A new approach to treating breast cancer kills 95-100% of cancer cells in mouse models of human estrogen-receptor-positive breast cancers and their metastases in bone, brain, liver and lungs. The newly developed drug, called ErSO, quickly shrinks even large tumors to undetectable levels.
Led by scientists at the University of Illinois Urbana-Champaign, the research team reports the findings in the journal Science Translational Medicine.
“Even when a few breast cancer cells do survive, enabling tumors to regrow over several months, the tumors that regrow remain completely sensitive to retreatment with ErSO,” said U. of I. biochemistry professor David Shapiro, who led the research with Illinois chemistry professor Paul Hergenrother. “It is striking that ErSO caused the rapid destruction of most lung, bone and liver metastases and dramatic shrinkage of brain metastases, since tumors that have spread to other sites in the body are responsible for most breast cancer deaths,” Shapiro said.
The activity of ErSO depends on a protein called the estrogen receptor, which is present in a high percentage of breast tumors. When ErSO binds to the estrogen receptor, it upregulates a cellular pathway that prepares cancer cells for rapid growth and protects them from stress. This pathway, called the anticipatory Unfolded Protein Response, or a-UPR, spurs the production of proteins that protect the cell from harm.
“The a-UPR is already on, but running at a low level, in many breast cancer cells,” Shapiro said. “It turns out that this pathway shields cancer cells from being killed off by anti-cancer drugs.”
Shapiro and former U. of I. medical scholar Neal Andruska first identified the a-UPR pathway in 2014 and reported the development of a compound that pushed the a-UPR pathway into overdrive to selectively kill estrogen-receptor-containing breast cancer cells.

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Scientists reverse age-related memory loss in mice

Scientists at Cambridge and Leeds have successfully reversed age-related memory loss in mice and say their discovery could lead to the development of treatments to prevent memory loss in people as they age.
In a study published today in Molecular Psychiatry, the team show that changes in the extracellular matrix of the brain — ‘scaffolding’ around nerve cells — lead to loss of memory with ageing, but that it is possible to reverse these using genetic treatments.
Recent evidence has emerged of the role of perineuronal nets (PNNs) in neuroplasticity — the ability of the brain to learn and adapt — and to make memories. PNNs are cartilage-like structures that mostly surround inhibitory neurons in the brain. Their main function is to control the level of plasticity in the brain. They appear at around five years old in humans, and turn off the period of enhanced plasticity during which the connections in the brain are optimised. Then, plasticity is partially turned off, making the brain more efficient but less plastic.
PNNs contain compounds known as chondroitin sulphates. Some of these, such as chondroitin 4-sulphate, inhibit the action of the networks, inhibiting neuroplasticity; others, such as chondroitin 6-sulphate, promote neuroplasticity. As we age, the balance of these compounds changes, and as levels of chondroitin 6-sulphate decrease, so our ability to learn and form new memories changes, leading to age-related memory decline.
Researchers at the University of Cambridge and University of Leeds investigated whether manipulating the chondroitin sulphate composition of the PNNs might restore neuroplasticity and alleviate age-related memory deficits.
To do this, the team looked at 20-month old mice — considered very old — and using a suite of tests showed that the mice exhibited deficits in their memory compared to six-month old mice.

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Parkinson's disease: How lysosomes become a hub for the propagation of the pathology

Over the last few decades, neurodegenerative diseases became one of the top 10 global causes of death. Researchers worldwide are making a strong effort to understand neurodegenerative diseases pathogenesis, which is essential to develop efficient treatments against these incurable diseases. However, our knowledge about the basic molecular mechanisms underlying the pathogenesis of neurodegenerative diseases is still lacking. A team of researchers found out the implication of lysosomes in the spread of Parkinson’s disease.
The accumulation of misfolded protein aggregates in affected brain regions is a common hallmark shared by several neurodegenerative diseases (NDs). Mounting evidence in cellular and in animal models highlights the capability of different misfolded proteins to be transmitted and to induce the aggregation of their endogenous counterparts, this process is called “seeding.” In Parkinson’s disease, the second most common ND, misfolded α-synuclein (α-syn) proteins accumulate in fibrillar aggregates within neurons. Those accumulations are named Lewy bodies.
α-syn fibrils spreads through TNTs inside lysosomes
In 2016, a team of researchers from the Institut Pasteur (Paris) and the French National Centre for Scientific Research (in French: CNRS, Centre national de la recherche scientifique) demonstrated that α- syn fibrils spread from donor to acceptor cells through tunneling nanotubes (TNTs). They also found out that these fibrils are transferred through TNTs inside lysosomes. “TNTs are actin-based membrane channels allowing the transfer of several cellular components including organelles between distant cells. Lysosomes are organelles normally deputed to the degradation and recycling of toxic/damaged cell material” describes Chiara Zurzolo, head of the Membrane Traffic and Pathogenesis Unit at the Institut Pasteur.
α-syn fibrils can modify lysosome shape and permeability to allow seeding and diffusion
Following this original discovery, researchers, now shed some light on how lysosomes participate in the spreading of α-syn aggregates through TNTs. “By using super-resolution and electron microscopy, we found that α-syn fibrils affect the morphology of lysosomes and impair their function in neuronal cells. We demonstrated for the first time that α-syn fibrils induce the peripheral redistribution of the lysosomes thus increasing the efficiency of α-syn fibrils’ transfer to neighbouring cells,” continues Chiara Zurzolo. They also showed that α-syn fibrils can permeabilize the lysosomal membrane, impairing the degradative function of lysosomes and allowing the seeding of soluble α-syn, which occurs mainly in those lysosomes. Thus, by impairing lysosomal function α-syn fibrils block their own degradation in lysosomes, that instead become a hub for the propagation of the pathology.
by impairing lysosomal function α-syn fibrils block their own degradation in lysosomes, that instead become a hub for the propagation of the pathology
This discovery contributes to the elucidation of the mechanism by which α-syn fibrils spread through TNTs, while also revealing the crucial role of lysosomes, working as a Trojan horse for both seeding and propagation of disease pathology. This information can be exploited to establish novel therapies to target these incurable diseases.
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Artificial intelligence models to analyze cancer images take shortcuts that introduce bias

Artificial intelligence tools and deep learning models are a powerful tool in cancer treatment. They can be used to analyze digital images of tumor biopsy samples, helping physicians quickly classify the type of cancer, predict prognosis and guide a course of treatment for the patient. However, unless these algorithms are properly calibrated, they can sometimes make inaccurate or biased predictions.
A new study led by researchers from the University of Chicago shows that deep learning models trained on large sets of cancer genetic and tissue histology data can easily identify the institution that submitted the images. The models, which use machine learning methods to “teach” themselves how to recognize certain cancer signatures, end up using the submitting site as a shortcut to predicting outcomes for the patient, lumping them together with other patients from the same location instead of relying on the biology of individual patients. This in turn may lead to bias and missed opportunities for treatment in patients from racial or ethnic minority groups who may be more likely to be represented in certain medical centers and already struggle with access to care.
“We identified a glaring hole in the in the current methodology for deep learning model development which makes certain regions and patient populations more susceptible to be included in inaccurate algorithmic predictions,” said Alexander Pearson, MD, PhD, assistant Assistant Professor of Medicine at UChicago Medicine and co-senior author. The study was published July 20, in Nature Communications.
One of the first steps in treatment for a cancer patient is taking a biopsy, or small tissue sample of a tumor. A very thin slice of the tumor is affixed to glass slide, which is stained with multicolored dyes for review by a pathologist to make a diagnosis. Digital images can then be created for storage and remote analysis by using a scanning microscope. While these steps are mostly standard across pathology labs, minor variations in the color or amount of stain, tissue processing techniques and in the imaging equipment can create unique signatures, like tags, on each image. These location-specific signatures aren’t visible to the naked eye, but are easily detected by powerful deep learning algorithms.
These algorithms have the potential to be a valuable tool for allowing physicians to quickly analyze a tumor and guide treatment options, but the introduction of this kind of bias means that the models aren’t always basing their analysis on the biological signatures it sees in the images, but rather the image artifacts generated by differences between submitting sites.
Pearson and his colleagues studied the performance of deep learning models trained on data from the Cancer Genome Atlas, one of the largest repositories of cancer genetic and tissue image data. These models can predict survival rates, gene expression patterns, mutations, and more from the tissue histology, but the frequency of these patient characteristics varies widely depending on which institutions submitted the images, and the model often defaults to the “easiest” way to distinguish between samples — in this case, the submitting site.
For example, if Hospital A serves mostly affluent patients with more resources and better access to care, the images submitted from that hospital will generally indicate better patient outcomes and survival rates. If Hospital B serves a more disadvantaged population that struggles with access to quality care, the images that site submitted will generally predict worse outcomes.
The research team found that once the models identified which institution submitted the images, they tended to use that as a stand in for other characteristics of the image, including ancestry. In other words, if the staining or imaging techniques for a slide looked like it was submitted by Hospital A, the models would predict better outcomes, whereas they would predict worse outcomes if it looked like an image from Hospital B. Conversely, if all patients in Hospital B had biological characteristics based on genetics that indicated a worse prognosis, the algorithm would link the worse outcomes to Hospital B’s staining patterns instead of things it saw in the tissue.
“Algorithms are designed to find a signal to differentiate between images, and it does so lazily by identifying the site,” Pearson said. “We actually want to understand what biology within a tumor is more likely to predispose resistance to treatment or early metastatic disease, so we have to disentangle that site-specific digital histology signature from the true biological signal.”
The key to avoiding this kind of bias is to carefully consider the data used to train the models. Developers can make sure that different disease outcomes are distributed evenly across all sites used in the training data, or by isolating a certain site while training or testing the model when the distribution of outcomes is unequal. The result will produce more accurate tools that can get physicians the information they need to quickly diagnose and plan treatments for cancer patients.
“The promise of artificial intelligence is the ability to bring accurate and rapid precision health to more people,” Pearson said. “In order to meet the needs of the disenfranchised members of our society, however, we have to be able to develop algorithms which are competent and make relevant predictions for everyone.”

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Scientists provide new insight on how to stop transcription of cancer cells

Scientists from the UCLA Jonsson Comprehensive Cancer Center have identified a key protein, transcription factor TAF12, that plays a critical role in the formation of a preinitiation complex, which consists of over one hundred proteins that are necessary for the transcription of protein-coding genes. The team found by eliminating TAF12, the entire preinitiation complex is destroyed and the genome-wide transcription is downregulated drastically.
The findings could help pave the way for cancer therapies that target TAF12, potentially stopping transcription in cancer cells and helping decrease the growth of cancerous tumors. TAF12 had previously been shown by others to be essential for growth of acute myeloid leukemia in mouse models.
“Identifying TAF12 as the cornerstone of the preinitiation complex allowed us to eliminate preinitiation complexes in the cell, and that has not been done before,” said senior author Michael Carey, PhD, professor of Biological Chemistry and director of the Gene Regulation Program at the Jonsson Cancer Center.
There have been significant advancements in the last couple of decades in principles about how the genome is organized and understanding the structures of transcription factors. However, the precise details of how enhancers communicate with promoters — genetic elements that control transcription in human and mouse genomes — to turn on genes is still not completely understood.
Efficient transcription, a basic and fundamental biological process that plays an important role in making proteins, requires the formation of a preinitiation complex that has over one hundred transcription factors including two major complexes termed co-activators. Understanding how these major co-activators function in cells is crucial in determining the precise mechanisms of gene activation. In this study, UCLA investigators looked to identify the key proteins in the co-activators to see if this knowledge of gene regulation and transcription could be eventually be applied to cancer therapeutics.
The researchers conducted an shRNA knockdown screen to identify key proteins in gene transcription in mouse embryonic stem cells. A technique termed auxin-inducible degradation was employed by the researchers to rapidly remove the identified transcription factor to determine the effects on formation of preinitiation complexes throughout the genome.
The research was funded in part by the National Institutes of Health General Medical Sciences.
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Geneticists pinpoint how a mutation causes devastating childhood cancer and successfully target tumor cells with tailored drug

Geneticists from Trinity College Dublin have discovered how a specific genetic mutation called H3K27M causes a devastating, incurable childhood cancer, known as diffuse midline glioma (DMG), and — in lab studies working with model cell types — successfully reverse its effects to slow cancer cell growth with a targeted drug.
Their landmark work — just published in leading international journal, Nature Genetics and supported by Worldwide Cancer Research and The Brain Tumour Charity — translates crucial new understanding of the genetics of DMG progression into a highly promising, targeted therapeutic approach and offers significant hope of improved treatments in the future.
The scientists now call for clinical trials to begin imminently, in which an already approved class of drugs called “EZH2 inhibitors” can be assessed. These drugs target the same key biological pathway involved in DMG as they do successfully in lymphomas and sarcomas — two cancers common in adults.
Adrian Bracken, Professor in Trinity’s School of Genetics and Microbiology, led the exciting research. He said: “We’ve taken a huge step forward in our study of DMG tumours and hope that the insights will help us design and implement precision oncology-based treatment approaches in DMG patients in the future. Crucially, ‘EZH2 inhibitor’ drugs have already received approval from the United States Food and Drug Administration for the treatment of two types of adult cancer. We propose these drugs could be impactful for children with DMG and, as a result, call for clinical trials to begin next.
“Ultimately, we hope that our work — together with that of others focused in this area — will lead to curative clinical approaches for what is a truly terrible disease that can devastate families and for which there are currently no therapeutic options.”
Paediatric gliomas like DMG are among the most devastating of childhood cancers. Tumours typically arise in the brain and are very challenging to treat, with prognosis extremely poor. As such, effective therapeutic options are urgently needed.
Dr Jane Pears, paediatric consultant oncologist at Our Lady’s Children’s Hospital, Crumlin, who treats children with this disease said: “Despite combined best efforts, these tumours remain a devastating diagnosis for children and their families. The best treatment we can currently offer may extend survival for a few months but is not curative. We are now entering an exciting era of expansion of our knowledge of this disease at a molecular level, which in turn will lead us towards more targeted treatments. Thanks to collaborative translational efforts between scientists, such as Prof. Bracken and his team working in the laboratory, and doctors in the clinical setting, this will hopefully lead to the improved outcomes that we all so dearly wish to see.”
Speaking to the importance of the work, Maeve Lowery, Professor of Translational Cancer Medicine at Trinity, and Academic Director of the Trinity St James’s Cancer Institute (TSJCI) said: “These findings have the potential to transform the treatment landscape of DMG tumours and improve outcomes for children with this challenging disease. Importantly, this pivotal work illustrates the success of a precision oncology approach — where understanding how cancers develop on a genomic level can accelerate the development of more effective treatments with less side effects. The Precision Oncology Research Program at TSJCI, led by Prof Bracken, will build on this success to continue to develop new and innovative treatment strategies for adult and childhood cancers.”
Dr Becky Birch, Head of Research at The Brain Tumour Charity, which helped fund the study, said: “This is a really promising discovery that we hope will now pave the way for new and targeted treatments to be developed for children with diffuse midline gliomas (DMGs). With average survival still heartbreakingly short at less than 12 months, we urgently need to find new options to help slow the growth of this rare and often-inoperable cancer and give children diagnosed more time to live. It’s really exciting that we now better understand how a specific genetic mutation may be driving the disease, and even more so that drugs that may inhibit this process have already been tested in other cancers. If further research can now design EZH2 inhibitors to more effectively target DMG cells, we hope these drugs can be quickly advanced into clinical trials for children diagnosed with this devastating disease.”
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Scientists discover gene therapy provides neuroprotection to prevent glaucoma vision loss

A form of gene therapy protects optic nerve cells and preserves vision in mouse models of glaucoma, according to research supported by NIH’s National Eye Institute. The findings suggest a way forward for developing neuroprotective therapies for glaucoma, a leading cause of visual impairment and blindness. The report was published in Cell.
Glaucoma results from irreversible neurodegeneration of the optic nerve, the bundle of axons from retinal ganglion cells that transmits signals from the eye to the brain to produce vision. Available therapies slow vision loss by lowering elevated eye pressure, however some glaucoma progresses to blindness despite normal eye pressure. Neuroprotective therapies would be a leap forward, meeting the needs of patients who lack treatment options.
“Our study is the first to show that activating the CaMKII pathway helps protect retinal ganglion cells from a variety of injuries and in multiple glaucoma models,” said the study’s lead investigator, Bo Chen, Ph.D., associate professor of ophthalmology and neuroscience at the Icahn School of Medicine at Mount Sinai in New York City.
The CaMKII (calcium/calmodulin-dependent protein kinase II) pathway regulates key cellular processes and functions throughout the body, including retinal ganglion cells in the eye. Yet the precise role of CaMKII in retinal ganglion cell health is not well understood. Inhibition of CaMKII activity, for example, has been shown to be either protective or detrimental to retinal ganglion cells, depending on the conditions.
Using an antibody marker of CaMKII activity, Chen’s team discovered that CaMKII pathway signaling was compromised whenever retinal ganglion cells were exposed to toxins or trauma from a crush injury to the optic nerve, suggesting a correlation between CaMKII activity and retinal ganglion cell survival.
Searching for ways to intervene, they found that activating the CaMKII pathway with gene therapy proved protective to the retinal ganglion cells. Administering the gene therapy to mice just prior to the toxic insult (which initiates rapid damage to the cells), and just after optic nerve crush (which causes slower damage), increased CaMKII activity and robustly protected retinal ganglion cells.
Among gene therapy-treated mice, 77% of retinal ganglion cells survived 12 months after the toxic insult compared with 8% in control mice. Six months following optic nerve crush, 77% of retinal ganglion cells had survived versus 7% in controls.
Similarly, boosting CaMKII activity via gene therapy proved protective of retinal ganglion cells in glaucoma models based on elevated eye pressure or genetic deficiencies.
Increasing retinal ganglion cell survival rates translated into greater likelihood of preserved visual function, according to cell activity measured by electroretinogram and patterns of activity in the visual cortex.
Three vision-based behavioral tests also confirmed sustained visual function among the treated mice. In a visual water task, the mice were trained to swim toward a submerged platform on the basis of visual stimuli on a computer monitor. Depth perception was confirmed by a visual cliff test based on the mouse’s innate tendency to step to the shallow side of a cliff. Lastly, a looming test determined that treated mice were more apt to respond defensively (by hiding, freezing or tail rattling) when shown an overhead stimulus designed to simulate a threat, compared with untreated mice.
“If we make retinal ganglion cells more resistant and tolerant to the insults that cause cell death in glaucoma, they might be able to survive longer and maintain their function,” Chen concluded.
This study was supported by NEI grants R01EY028921, R01EY024986. NEI is part of the National Institutes of Health.
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Untwisting DNA reveals new force that shapes genomes

Advances in microscopy have enabled researchers to picture loops of DNA strands for the first time. The images reveal how the human genome organises itself in three-dimensional space at much higher resolution than previously possible.
The findings, published in a new study in the journal Molecular Cell, also reveal that the process of DNA being copied into RNA — transcription — indirectly shapes the architecture of the genome. An international team led by Pia Cosma at the Centre for Genomic Regulation (CRG) in Barcelona and Melike Lakadamyali at the Perelman School of Medicine at the University of Pennsylvania in the United States found that transcription generates a force that moves across DNA strands like ripples through water.
Known as supercoiling, the force causes structural proteins known as cohesins to ‘surf’ across DNA strands, changing the scaffold’s architecture and morphing the overall shape of the genome. While it is known that genome organization regulates gene transcription, it is the first-time researchers have found transcription to impact genome organization the other way round through supercoiling.
According to the researchers, the discovery of this new force may have future implications for the understanding of genetic diseases such as Cornelia de Lange syndrome, which is caused by mutations in genes encoding for cohesin or cohesin regulators. The findings may also be relevant for developmental disorders linked to how chromatin folds, as well as opening new avenues of research in genome fragility and cancer development.
The researchers studied the biological mechanisms that enable two metres of DNA to be squeezed into a tight space in each human cell. In this condensed state, the DNA, also known as chromatin, contains many loops that bring together different regions of the genome that would normally be far apart. The resulting physical proximity is important for transcribing DNA into RNA which then makes proteins, making chromatin looping a fundamental biological mechanism for human health and disease.
According to Vicky Neguembor, Staff Scientist at the CRG and first author of the paper, “Chromatin looping is what allows individual cells to switch different information on and off, which is why for example a neuron or a muscle cell with the same genomic information can still behave so differently. Loops are also one of the ways the genome gets compacted to fit into the nucleus.”
“What we have found is important because it shows the biological process of transcription plays an additional role beyond its fundamental task of creating RNA that eventually turn into proteins. Transcription indirectly compacts the genome in an efficient manner and helps different regions of the genome talk to each other.”
Previous techniques used to study this process could predict where loops were located but not their actual shape or how they look like within the cells. To improve image resolution, the researchers used a special type of microscopy that use high-power lasers under specific chemical conditions to track the blinking of fluorescent molecules. The technique provides ten times higher resolution than conventional microscopy, and combined with advanced imaging analysis techniques the researchers were able to identify chromatin loops, and the cohesins that hold the structure together like paper clips, within intact cells.
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