The Role of Quality and Speed in Custom Model Generation – FierceBiotech

The pressure to produce results quickly during the drug discovery and development process continues to increase as does the role of genetically engineered custom mouse models. However, even the fastest custom mouse model generation projects take about 6 months to reach the stage when a few F1 heterozygous mice are available for experiments or breeding. This timeline increases if more than a few heterozygotes or homozygotes are needed. Taconics ExpressMODEL portfolio of products shifts the deliverable of a model generation project from a few heterozygous F1 mice to a much larger cohort of 10-100 mice while reducing the timeline to obtaining data, adding predictability, all without compromising essential quality control steps. By applying innovative thinking and leveraging our ability to seamlessly integrate custom model generation, embryology and colony management services, the ExpressMODEL portfolio achieves the industry's fastest timelines to study cohort with no compromise in quality for models generated using embryonic stem cell (ESC), CRISPR, or random integration transgenic (RITg) methodology.

Regardless of the methodology used to generate the founder animals, ExpressMODEL is built around the concept that using in vitro fertilization (IVF) rather than conventional breeding to generate the F1 mice from founders has a number of distinct advantages including:

However, ExpressMODEL is more than simply using IVF to produce F1 mice because the quality of the male founders needs to be high in order to fully realize the advantages IVF provides. High quality means that founder males need to have both a high percentage of the desired genetically-modified gene and a high fertility rate. Thus, the candidate founder males need to be well-characterized. Because the different methodologies used for model generation produce founders with different characteristics, we have developed unique founder analysis protocols to fit the three different methodologies. The founders produced from injection of ESCs into blastocyst-stage embryos are called chimeras because they are derived from two different populations of genetically distinct cells that originated from different embryos. The founders produced by introducing CRISPR reagents or transgenic DNA into one-cell embryos (zygotes) are mosaics meaning they are composed of two or more different populations of genetically distinct cells that originated from the same embryo.

ExpressMODEL: Embryonic stem cell (ESC)

ESC-mediated mouse model generation remains the gold standard and best choice for complex projects such as genomic replacement humanizations. Using ExpressMODEL: ESC, the timeline for a typical project that would take 66 weeks to deliver a homozygous study-size cohort is reduced to 54 weeks, saving at least 3 months. The key components of ExpressMODEL: ESC are:

The data from these analyses facilitate the choice of founder male(s) to be utilized for the IVF to produce an F1 heterozygous cohort that is sized to meet the customers downstream goals and timeline requirements. It is important to note that all quality control steps in vector construction and ES cell targeting are preserved.

ExpressMODEL: CRISPR

Two great advantages of CRISPR methodology are the speed at which a genetically engineered model can be generated and the ability to modify a wide range of genetic backgrounds, including existing genetically-engineered models. Using ExpressMODEL: CRISPR, the timeline for a typical project that would take 48 weeks to deliver a homozygous study-size cohort is reduced to 36 weeks, saving at least 3 months. ExpressMODEL: CRISPR combines our ability to produce founders with a low degree of mosaicism and to accurately estimate the degree of mosaicism of each founder male. The key components of ExpressMODEL: CRISPR are:

ExpressMODEL: Random Integration Transgenic (RITg)

More than 30 years since the first RITg model was generated, the method continues to be a favored path to quickly generate gain of function models that express an ectopic gene. However, because genomic integration of the transgene is random in each injected embryo, the resulting founder line are unique and may or may not perform to the desired specifications. Additionally, each founder often has transgene insertions at multiple sites and the configuration and copy number of those insertions differs. Thus, RITg founders can be more genetically complex than CRISPR founders. As a result, common practice is to separately propagate multiple lines to generate offspring for extensive transgene expression studies. These data are then used to determine which founder line(s) to propagate. The cost and time of this downstream breeding and characterization of multiple founder lines greatly exceeds the original cost to generate the lines and takes significant additional time. Because transgene expression is assessed in founder animals, ExpressMODEL: RITg takes the guesswork out of the process and allows one to avoid the cost of breeding and characterizing multiple founder lines. Moreover, it reduces project timeline by at least 12 weeks and potentially up to 24 weeks or more. The key components of ExpressMODEL: RITg are:

Additional customizable options are available including the provision of tissue lysates and fixed tissue for protein expression analyses, and transgene mapping analysis to accurately determine the transgene integration site and configuration.

Taconics ExpressMODEL suite of technologies is designed to reduce the custom model generation timeline from project conception to study cohort without taking any shortcuts that compromise quality. Taconic provides a seamless end-to-end solution incorporating industry leading model generation, embryology, and colony management capabilities that allows your project to travel in the express lane.

Interested in learning more about custom animal model generation? Visit Taconic's website at http://www.taconic.com.

This article was created in collaboration with the sponsoring company and our sales and marketing team. The editorial team does not contribute.

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The Role of Quality and Speed in Custom Model Generation - FierceBiotech

Stem cells may be the key to saving white rhinos from extinction – Sciworthy

It is too late for conservation efforts to save the northern white rhinoceros, but with recent scientific advancements there may still be hope to bring back this beloved species. In a recently published paper, scientist Marisa Korody and her colleagues at San Diego Zoo Global (USA) and at the Department of Molecular Medicine at Scripps Research (USA) describe their exciting progress on using stem cells to revive the northern white rhino.

The northern white rhino is functionally extinct, meaning there are not enough of these rhinos left to save the species. In fact there are only two northern white rhinos left: a mother and a daughter. But for decades, scientists have preserved cell samples from 15 northern white rhinos containing enough genetic material to potentially bring this species back from the brink. These preserved samples hold fibroblast cells the type of skin cells that secrete collagen from white rhinos. With these scientists newly developed methods, fibroblast cells can be converted into something much more valuable: induced pluripotent stem cells. These stem cells can differentiate into any cell type in the body including heart cells, muscle cells, and reproductive cells.

In theory, by converting fibroblast cells into reproductive cells, scientists could create genetically unique rhino embryos. Alongside other assisted reproduction technologies, scientists could implant a new embryo into a closely-related southern white rhino, where the baby northern white rhino could develop as an otherwise normal pregnancy. By completing this process multiple times, scientists may be able to establish a stable population of northern white rhinos.

In 2011, this research team generated induced pluripotent stem cells from the samples of another endangered species, but unfortunately since this process was found to harm the recipient genomes, this method was largely unsuccessful. Despite this setback, in 2015 the authors met with colleagues worldwide to consider ways to save the northern white rhino, and they concluded that methods involving induced pluripotent stem cells may still be the most promising solution. Over the following years, the scientists worked to improve their methods, and these improvements are documented in their recent paper. These experiments represent the first step in a long-term plan to bring the northern white rhino back through assisted reproduction techniques.

Right from the start, the scientists faced a whole host of challenges. Through trial and error they modified the growth medium for the cells, optimizing it for rhinoceros cells. With their improved growth medium, scientists successfully generated induced pluripotent stem cell lines from 11 rhinoceros individuals. This has never been done before and represents a huge stride forward in the path to recovering this species.

Before trying to make their first rhino, the scientists needed to stress these induced pluripotent stem cells and sequence their genomes to determine if the cell quality is good enough to potentially produce new, viable rhinos. They maintained colonies of these cells in long-term cultures and exposed these colonies to different conditions to give insight into how resilient these cells could be. These tests demonstrated that long-term culture did not affect the potential for these cells to differentiate into cardiac lineage cells, confirming that these cells are stable long-term. The researchers also confirmed that these pluripotent cells could potentially produce gametes, the egg and sperm cells that are used for sexual reproduction. These advancements indicate that with these newly developed protocols, induced pluripotent stem cells are a promising tool that could someday help recover the northern white rhino.

Although this study includes some exciting results, there is still much work to do. For example, scientists must now sequence the genomes of the northern and southern white rhino so other researchers can analyze the stem cells ability to stay the same over time. Despite the work that still needs to be done, these promising advancements could someday help the northern white rhino population recover. This method may also work for saving other endangered or extinct species, as long as the genetic material needed is available. Long-term, these scientists plan to continue a series of experiments that could ultimately bring this beloved rhino, and potentially other endangered species, back from the brink of extinction.

Original study: Rewinding Extinction in the Northern White Rhinoceros: Genetically Diverse Induced Pluripotent Stem Cell Bank for Genetic Rescue

Study published on: February 15, 2021

Study author(s): Marisa L. Korody, Sarah M. Ford, Thomas D. Nguyen, Cullen G. Pivaroff, Iigo Valiente-Alandi, Suzanne E. Peterson, Oliver A. Ryder, and Jeanne F. Loring

The study was done at: San Diego Zoo Global (USA), Scripps Research (USA)

The study was funded by: San Diego Zoo Global and San Diego Zoo Wildlife Conservancy donors, including Anne and Christopher Lewis, and the Robert Kleberg and John and Beverly Stauffer Foundations; and Uma Lakshmipathy from Thermo Fisher Scientific for providing supplies

Raw data availability: Contact author for data (all other data are accessible from the article or supplementary materials)

Featured image credit: Hein waschefort, CC BY-SA 3.0, via Wikimedia Commons

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Stem cells may be the key to saving white rhinos from extinction - Sciworthy

Healthcare Researchers Are Putting HUMAN Immune Systems In Pigs To Study Illnesses-Here’s The Tech Behind It – Tech Times

RJ Pierce, Tech Times 05 October 2021, 09:10 am

Healthcare research has gone a long way from the dark days of old, when today's simplest illnesses can be a death sentence. And now, there's reason to look forward to a brighter future because of this news.

(Photo : Getty Images )

According to BigThink, a team from Iowa State University claimed that they've found a way to integrate human immune systems in pigs, as a way to study illnesses much closer.

In other words, they basically "humanized" the pigs to try and find out how to better treat human diseases in the future.

The implications of their research are quite profound, too. As per the researchers, this breakthrough could theoretically advance healthcare research in areas such as virus and vaccines, cancer, and even stem cell treatments.

Before this, scientists often used mice in their biotech and biomedical experiments. However, the problem is that mice-based results don't translate well to humans.

Aside from mice, primates have also been used in related fields of healthcare research due to their direct biological connections with humans. Nevertheless, a lot of ethical issues popped up, thus leading to the retirement of primates, including chimpanzees, from this type of research eight years ago.

This won't be the first time that healthcare research has produced what's basically human-animal hybrids to study illnesses.

Three years ago, a team of scientists from Rockefeller University in New York managed to create a human-chicken embryo, in an attempt to take a closer look at the intricacies of stem cell therapies.

Read also: Scientists Want To Create Part-Human Part-Animal Chimeras To Find Cure For Diseases

It started when the same scientists from Iowa State University discovered a genetic mutation in pigs that caused an illness called SCID (Severe Combined Immunodeficiency).

Some people may know this from the film "The Boy In The Plastic Bubble" from 1976, which tells the story of a child whose immune system never fully developed. As such, he was forced to literally live inside a sterile bubble because even the slightest cold would kill him.

Upon this discovery, the researchers then developed a pig that's far more immunocompromised compared to a person with SCID, then successfully "humanized" it by injecting human immune stem cells into the livers of piglets.

The researchers were able to do this by using ultrasound imaging as a guide.

Ultrasound imaging, also known as sonography, makes use of high-frequency waves to look inside the body.

(Photo : Getty Images )

The resulting pigs had excellent healthcare research potential, because they were found to have human immune cells in their blood, thymus gland, spleen, and liver.

However, the SCID-afflicted pigs are in constant danger of infections. As such, they have to be housed in so-called bubble biocontainment facilities. These facilities work by maintaining high positive pressure, which keeps dangerous pathogens out. All staff members have to wear sterile protective gear at all times.

They've basically turned into their own versions of the boy in the bubble.

Before this research, pigs have often been used to know more about the human body because of how strikingly similar their anatomy is to humans.

In fact, a few scientists even believe that with how biologically similar pigs are to humans, they might be classified into an animal family occupied by primates, reportedScience.org.au.

But of course, there have been ethical issues involving the use of these human-animal hybrids for healthcare research. Eventually, though, the National Institutes of Health (NIH) relaxed their regulations a bit back in 2016, which made it easier for scientists to transfer human stem cells into animal embryos.

Related: Scientists Grow Sheep Embryos With Human Cells To Revolutionize Organ Transplant

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Written by RJ Pierce

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Healthcare Researchers Are Putting HUMAN Immune Systems In Pigs To Study Illnesses-Here's The Tech Behind It - Tech Times