̽��ֱ�� of Cambridge - Department of Physiology, Development and Neuroscience (PDN)

Scientists identify genes that make humans and Labradors more likely to become obese

jg533 — Thu, 06 Mar 2025 19:03:04 +0000

Researchers studying British Labrador retrievers have identified multiple genes associated with canine obesity and shown that these genes are also associated with obesity in humans.

̽��ֱ��dog gene found to be most strongly associated with obesity in Labradors is called DENND1B. Humans also carry the DENND1B gene, and the researchers found that this gene is also linked with obesity in people.

DENND1B was found to directly affect a brain pathway responsible for regulating the energy balance in the body, called the leptin melanocortin pathway.

An additional four genes associated with canine obesity, but which exert a smaller effect than DENND1B, were also mapped directly onto human genes.

“These genes are not immediately obvious targets for weight-loss drugs, because they control other key biological processes in the body that should not be interfered with.

But the results emphasise the importance of fundamental brain pathways in controlling appetite and body weight,” said Alyce McClellan in the ̽��ֱ�� of Cambridge’s Department of Physiology, Development and Neuroscience, and joint first author of the report.

“We found that dogs at high genetic risk of obesity were more interested in food,” said Natalie Wallis in the ̽��ֱ�� of Cambridge’s Department of Physiology, Development and Neuroscience, and joint first author of the report.

She added: “We measured how much dogs pestered their owners for food and whether they were fussy eaters. Dogs at high genetic risk of obesity showed signs of having higher appetite, as has also been shown for people at high genetic risk of obesity.”

̽��ֱ��study found that owners who strictly controlled their dogs’ diet and exercise managed to prevent even those with high genetic risk from becoming obese - but much more attention and effort was required.

Similarly, people at high genetic risk of developing obesity will not necessarily become obese, if they follow a strict diet and exercise regime - but they are more prone to weight gain.

As with human obesity, no single gene determined whether the dogs were prone to obesity; the net effect of multiple genetic variants determined whether dogs were at high or low risk.

̽��ֱ��results were published on 6 March in the journal 'Science'.

“Studying the dogs showed us something really powerful: owners of slim dogs are not morally superior. ̽��ֱ��same is true of slim people. If you have a high genetic risk of obesity, then when there’s lots of food available you’re prone to overeating and gaining weight unless you put a huge effort into not doing so,” said Dr Eleanor Raffan, a researcher in the ̽��ֱ�� of Cambridge’s Department of Physiology, Development and Neuroscience who led the study.

She added: “By studying dogs we could measure their desire for food separately to the control owners exerted over their dog’s diet and exercise. In human studies, it’s harder to study how genetically driven appetite requires greater willpower to remain slim, as both are affecting the one person.”

̽��ֱ��current human obesity epidemic is mirrored by an obesity epidemic in dogs. About 40-60% of pet dogs are overweight or obese, which can lead to a range of health problems.

Dogs are a good model for studying human obesity: they develop obesity through similar environmental influences as humans, and because dogs within any given breed have a high degree of genetic similarity, their genes can be more easily linked to disease.

To get their results, the researchers recruited owners with pet dogs in which they measured body fat, scored ‘greediness’, and took a saliva sample for DNA. Then they analysed the genetics of each dog. By comparing the obesity status of the dog to its DNA, they could identify the genes linked to canine obesity.
Dogs carrying the genetic variant most associated with obesity, DENND1B, had around 8% more body fat than those without it.

̽��ֱ��researchers then examined whether the genes they identified were relevant to human obesity. They looked at both large population-based studies, and at cohorts of patients with severe, early onset obesity where single genetic changes are suspected to cause the weight gain.

̽��ֱ��researchers say owners can keep their dogs distracted from constant hunger by spreading out each daily food ration, for example by using puzzle feeders or scattering the food around the garden so it takes longer to eat, or by choosing a more satisfying nutrient composition for their pets.

Raffan said: “This work shows how similar dogs are to humans genetically. Studying the dogs meant we had reason to focus on this particular gene, which has led to a big advance in understanding how our own brain controls our eating behaviour and energy use.”

̽��ֱ��research was funded by Wellcome, the BBSRC, Dogs Trust, Morris Animal Foundation, MRC, France Genomique consortium, European Genomic Institute for Diabetes, French National Center for Precision Diabetic Medicine, Royal Society, NIHR, Botnar Foundation, Bernard Wolfe Health Neuroscience Endowment, Leducq Fondation, Kennel Club Charitable Trust.

Reference
Wallis, N J et al: ‘Canine genome-wide association study identifies DENND1B as an obesity gene in dogs and humans.’ Science, March 2025. DOI: 10.1126/science.ads2145

Researchers at the ̽��ֱ�� of Cambridge have discovered genes linked to obesity in both Labradors and humans. They say the effects can be over-ridden with a strict diet and exercise regime.

Dogs at high genetic risk of obesity showed signs of having higher appetite, as has also been shown for people at high genetic risk of obesity.

Natalie Wallis

James Barker on Unsplash

Labrador licking nose

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Glaucoma drug shows promise against neurodegenerative diseases, animal studies suggest

cjb250 — Thu, 31 Oct 2024 10:00:09 +0000

Researchers in the UK Dementia Research Institute at the ̽��ֱ�� of Cambridge screened more than 1,400 clinically-approved drug compounds using zebrafish genetically engineered to make them mimic so-called tauopathies. They discovered that drugs known as carbonic anhydrase inhibitors – of which the glaucoma drug methazolamide is one – clear tau build-up and reduce signs of the disease in zebrafish and mice carrying the mutant forms of tau that cause human dementias.

Tauopathies are neurodegenerative diseases characterised by the build-up in the brain of tau protein ‘aggregates’ within nerve cells. These include forms of dementia, Pick's disease and progressive supranuclear palsy, where tau is believed to be the primary disease driver, and Alzheimer’s disease and chronic traumatic encephalopathy (neurodegeneration caused by repeated head trauma, as has been reported in football and rugby players), where tau build-up is one consequence of disease but results in degeneration of brain tissue.

There has been little progress in finding effective drugs to treat these conditions. One option is to repurpose existing drugs. However, drug screening – where compounds are tested against disease models – usually takes place in cell cultures, but these do not capture many of the characteristics of tau build-up in a living organism.

To work around this, the Cambridge team turned to zebrafish models they had previously developed. Zebrafish grow to maturity and are able to breed within two to three months and produce large numbers of offspring. Using genetic manipulation, it is possible to mimic human diseases as many genes responsible for human diseases often have equivalents in the zebrafish.

In a study published today in Nature Chemical Biology, Professor David Rubinsztein, Dr Angeleen Fleming and colleagues modelled tauopathy in zebrafish and screened 1,437 drug compounds. Each of these compounds has been clinically approved for other diseases.

Dr Ana Lopez Ramirez from the Cambridge Institute for Medical Research, Department of Physiology, Development and Neuroscience and the UK Dementia Research Institute at the ̽��ֱ�� of Cambridge, joint first author, said: “Zebrafish provide a much more effective and realistic way of screening drug compounds than using cell cultures, which function quite differently to living organisms. They also enable us to do so at scale, something that it not feasible or ethical in larger animals such as mice.”

Using this approach, the team showed that inhibiting an enzyme known as carbonic anhydrase – which is important for regulating acidity levels in cells – helped the cell rid itself of the tau protein build-up. It did this by causing the lysosomes – the ‘cell’s incinerators’ – to move to the surface of the cell, where they fused with the cell membrane and ‘spat out’ the tau.

When the team tested methazolamide on mice that had been genetically engineered to carry the P301S human disease-causing mutation in tau, which leads to the progressive accumulation of tau aggregates in the brain, they found that those treated with the drug performed better at memory tasks and showed improved cognitive performance compared with untreated mice.

Analysis of the mouse brains showed that they indeed had fewer tau aggregates, and consequently a lesser reduction in brain cells, compared with the untreated mice.

Fellow joint author Dr Farah Siddiqi, also from the Cambridge Institute for Medical Research and the UK Dementia Research Institute, said: “We were excited to see in our mouse studies that methazolamide reduces levels of tau in the brain and protects against its further build-up. This confirms what we had shown when screening carbonic anhydrase inhibitors using zebrafish models of tauopathies.”

Professor Rubinsztein from the UK Dementia Research Institute and Cambridge Institute for Medical Research at the ̽��ֱ�� of Cambridge, said: “Methazolamide shows promise as a much-needed drug to help prevent the build-up of dangerous tau proteins in the brain. Although we’ve only looked at its effects in zebrafish and mice, so it is still early days, we at least know about this drug’s safety profile in patients. This will enable us to move to clinical trials much faster than we might normally expect if we were starting from scratch with an unknown drug compound.

“This shows how we can use zebrafish to test whether existing drugs might be repurposed to tackle different diseases, potentially speeding up significantly the drug discovery process.”

̽��ֱ��team hopes to test methazolamide on different disease models, including more common diseases characterised by the build-up of aggregate-prone proteins, such as Huntington’s and Parkinson’s diseases.

̽��ֱ��research was supported by the UK Dementia Research Institute (through UK DRI Ltd, principally funded through the Medical Research Council), Tau Consortium and Wellcome.

Reference
Lopez, A & Siddiqi, FH et al. Carbonic anhydrase inhibition ameliorates tau toxicity via enhanced tau secretion. Nat Chem Bio; 31 Oct 2024; DOI: 10.1038/s41589-024-01762-7

A drug commonly used to treat glaucoma has been shown in zebrafish and mice to protect against the build-up in the brain of the protein tau, which causes various forms of dementia and is implicated in Alzheimer’s disease.

Zebrafish provide a much more effective and realistic way of screening drug compounds than using cell cultures, which function quite differently to living organisms

Ana Lopez Ramirez

Kuznetsov_Peter

Zebrafish

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Mother’s gut microbiome during pregnancy shapes baby’s brain development

jg533 — Tue, 20 Aug 2024 23:30:03 +0000

Researchers have compared the development of the fetal brain in mice whose mothers had no bacteria in their gut, to those whose mothers were given Bifidobacterium breve orally during pregnancy, but had no other bacteria in their gut.

Nutrient transport to the brain increased in fetuses of mothers given Bifidobacterium breve, and beneficial changes were also seen in other cell processes relating to growth.

Bifidobacterium breve is a ‘good bacteria’ that occurs naturally in our gut, and is available as a supplement in probiotic drinks and tablets.

Obesity or chronic stress can alter the gut microbiome of pregnant women, often resulting in fetal growth abnormalities. ̽��ֱ��babies of up to 10% of first-time mothers have low birth weight or fetal growth restriction. If a baby hasn't grown properly in the womb, there is an increased risk of conditions like cerebral palsy in infants and anxiety, depression, autism, and schizophrenia in later life.

These results suggest that improving fetal development - specifically fetal brain metabolism - by taking Bifidobacterium breve supplements while pregnant may support the development of a healthy baby.

̽��ֱ��results are published today in the journal Molecular Metabolism.

“Our study suggests that by providing ‘good bacteria’ to the mother we could improve the growth and development of her baby while she’s pregnant,” said Dr Jorge Lopez-Tello, a researcher in the ̽��ֱ�� of Cambridge’s Centre for Trophoblast Research, first author of the report.

He added: “This means future treatments for fetal growth restriction could potentially focus on altering the gut microbiome through probiotics, rather than offering pharmaceutical treatments - with the risk of side effects - to pregnant women.”

“ ̽��ֱ��design of therapies for fetal growth restriction are focused on improving blood flow pathways in the mother, but our results suggest we’ve been thinking about this the wrong way - perhaps we should be more focused on improving maternal gut health,” said Professor Amanda Sferruzzi-Perri, a researcher in the ̽��ֱ�� of Cambridge’s Centre for Trophoblast Research and senior author of the report, who is also a Fellow of St John’s College, Cambridge.

She added: “We know that good gut health - determined by the types of microbes in the gut - helps the body to absorb nutrients and protect against infections and diseases.”

̽��ֱ��study was carried out in mice, which allowed the effects of Bifidobacterium breve to be assessed in a way that would not be possible in humans - the researchers could precisely control the genetics, other microorganisms and the environment of the mice. But they say the effects they measured are likely to be similar in humans.

They now plan further work to monitor the brain development of the offspring after birth, and to understand how Bifidobacterium breve interacts with the other gut bacteria present in natural situations.

Previous work by the same team found that treating pregnant mice with Bifidobacterium breve improves the structure and function of the placenta. This also enables a better supply of glucose and other nutrients to the developing fetus and improves fetal growth.

“Although further research is needed to understand how these effects translate to humans, this exciting discovery may pave the way for future clinical studies that explore the critical role of the maternal microbiome in supporting healthy brain development before birth,” said Professor Lindsay Hall at the ̽��ֱ�� of Birmingham, who was also involved in the research.

While it is well known that the health of a pregnant mother is important for a healthy baby, the effect of her gut bacteria on the baby’s development has received little attention.

Reference

Lopez-Tello, J, et al: ‘Maternal gut Bifidobacterium breve modifies fetal brain metabolism in germ-free mice.’ Molecular Metabolism, August 2024. DOI: 10.1016/j.molmet.2024.102004

A study in mice has found that the bacteria Bifidobacterium breve in the mother’s gut during pregnancy supports healthy brain development in the fetus.

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Cambridge scientists elected as Members of the European Molecular Biology Organisation

jg533 — Tue, 09 Jul 2024 12:00:56 +0000

Five Cambridge researchers join the community of over 2,100 leading life scientists today as the European Molecular Biology Organisation (EMBO) announces its newest Members in its 60th anniversary year.

Pioneering Code of Practice released for use of stem cell-based embryo models in research

jg533 — Thu, 04 Jul 2024 08:17:57 +0000

̽��ֱ�� ̽��ֱ�� of Cambridge, in partnership with the Progress Educational Trust, has led work to create the first ever UK guidelines for the generation and use of stem cell-based embryo models in research.

Genetic mutation in a quarter of all Labradors hard-wires them for obesity

jg533 — Wed, 06 Mar 2024 19:06:36 +0000

This obesity-driving combination means that dog owners must be particularly strict with feeding and exercising their Labradors to keep them slim.

̽��ֱ��mutation is in a gene called POMC, which plays a critical role in hunger and energy use.

Around 25% of Labradors and 66% of flatcoated retriever dogs have the POMC mutation, which researchers previously showed causes increased interest in food and risk of obesity.

̽��ֱ��new study reveals how the mutation profoundly changes the way Labradors and flatcoated retrievers behave around food. It found that although they don’t need to eat more to feel full, they are hungrier in between meals.

In addition, dogs with the POMC mutation were found to use around 25% less energy at rest than dogs without it, meaning they don’t need to consume as many calories to maintain a healthy body weight.

“We found that a mutation in the POMC gene seems to make dogs hungrier. Affected dogs tend to overeat because they get hungry between meals more quickly than dogs without the mutation,” said Dr Eleanor Raffan, a researcher in the ̽��ֱ�� of Cambridge’s Department of Physiology, Development and Neuroscience who led the study.

She added: “All owners of Labradors and flatcoated retrievers need to watch what they’re feeding these highly food-motivated dogs, to keep them a healthy weight. But dogs with this genetic mutation face a double whammy: they not only want to eat more, but also need fewer calories because they’re not burning them off as fast.”

̽��ֱ��POMC mutation was found to alter a pathway in the dogs’ brains associated with body weight regulation. ̽��ֱ��mutation triggers a starvation signal that tells their body to increase food intake and conserve energy, despite this being unnecessary.

̽��ֱ��results are published today in the journal Science Advances.

Raffan said: “People are often rude about the owners of fat dogs, blaming them for not properly managing their dogs’ diet and exercise. But we’ve shown that Labradors with this genetic mutation are looking for food all the time, trying to increase their energy intake. It’s very difficult to keep these dogs slim, but it can be done.”

̽��ֱ��researchers say owners can keep their retrievers distracted from this constant hunger by spreading out each daily food ration, for example by using puzzle feeders or scattering the food around the garden so it takes longer to eat.

In the study, 87 adult pet Labrador dogs - all a healthy weight or moderately overweight - took part in several tests including the ‘sausage in a box’ test.

First, the dogs were given a can of dogfood every 20 minutes until they chose not to eat any more. All ate huge amounts of food, but the dogs with the POMC mutation didn’t eat more than those without it. This showed that they all feel full with a similar amount of food.

Next, on a different day, the dogs were fed a standard amount of breakfast. Exactly three hours later they were offered a sausage in a box and their behaviour was recorded. ̽��ֱ��box was made of clear plastic with a perforated lid, so the dogs could see and smell the sausage, but couldn’t eat it.

̽��ֱ��researchers found that dogs with the POMC mutation tried significantly harder to get the sausage from the box than dogs without it, indicating greater hunger.

̽��ֱ��dogs were then allowed to sleep in a special chamber that measured the gases they breathed out. This revealed that dogs with the POMC mutation burn around 25% fewer calories than dogs without it.

̽��ֱ��POMC gene and the brain pathway it affects are similar in dogs and humans. ̽��ֱ��new findings are consistent with reports of extreme hunger in humans with POMC mutations, who tend to become obese at an early age and develop a host of clinical problems as a result.

Drugs currently in development for human obesity, underactive sexual desire and certain skin conditions target this brain pathway, so understanding it fully is important.

A mutation in the POMC gene in dogs prevents production of two chemical messengers in the dog brain, beta-melanocyte stimulating hormone (β-MSH) and beta-endorphin, but does not affect production of a third, alpha-melanocyte stimulating hormone (α-MSH).

Further laboratory studies by the team suggest that β-MSH and beta-endorphin are important in determining hunger and moderating energy use, and their role is independent of the presence of α-MSH. This challenges the previous belief, based on research in rats, that early onset human obesity due to POMC mutations is caused only by a lack of α-MSH. Rats don’t produce beta-melanocyte stimulating hormone, but humans and dogs produce both α- and β-MSH.

̽��ֱ��research was funded by ̽��ֱ��Dogs Trust and Wellcome.

Reference: Dittmann, M T et al: ‘Low resting metabolic rate and increased hunger due to β-MSH and β-endorphin deletion in a canine model.’ Science Advances, March 2024. DOI: 10.1126/sciadv.adj3823

New research finds around a quarter of Labrador retriever dogs face a double-whammy of feeling hungry all the time and burning fewer calories due to a genetic mutation.

Labradors with this genetic mutation are looking for food all the time, trying to increase their energy intake. It’s very difficult to keep these dogs slim, but it can be done.

Eleanor Raffan

A quarter of Labradors are hard-wired for obesity

Jane Goodall

Labrador retriever dog

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Unborn babies use ‘greedy’ gene from dads to ‘remote-control’ mums into feeding them extra food

Anonymous — Tue, 11 Jul 2023 15:00:32 +0000

̽��ֱ��unborn baby ‘remote controls’ its mother’s metabolism so the two are in a nutritional tug of war. ̽��ֱ��mother’s body wants the baby to survive but needs to keep enough glucose and fats circulating in her system for her own health, to be able to deliver the baby, breastfeed and to reproduce again.

A new study from the ̽��ֱ�� of Cambridge published today examines how the placenta communicates with the mother through the release of hormones so she will accommodate her baby’s growth. ̽��ֱ��placenta is a vital organ that develops with the fetus in pregnant women and other female mammals to support the developing fetus. In pregnant mice, scientists selectively altered the signalling cells in the placenta that tell mothers to allocate nutrients to her developing fetuses.

Professor Amanda Sferruzzi-Perri, Professor in Fetal and Placental Physiology, a Fellow of St John’s College and co-senior author of the paper, said: “It’s the first direct evidence that a gene inherited from the father is signalling to the mother to divert nutrients to the fetus.”

Dr Miguel Constancia, MRC Investigator based at the Wellcome-MRC Institute of Metabolic Science and co-senior author of the paper, said: “ ̽��ֱ��baby’s remote control system is operated by genes that can be switched on or off depending on whether they are a ‘dad’s’ or ‘mum’s’ gene’, the so-called imprinted genes.

“Genes controlled by the father are ‘greedy’ and ‘selfish’ and will tend to manipulate maternal resources for the benefit of the fetuses, so to grow them big and fittest. Although pregnancy is largely cooperative, there is a big arena for potential conflict between the mother and the baby, with imprinted genes and the placenta thought to play key roles.”

̽��ֱ��findings by researchers from the Centre for Trophoblast Research at Cambridge’s Department of Physiology, Development and Neuroscience and the Medical Research Council Metabolic Diseases Unit, part of the Wellcome-MRC Institute of Metabolic Science, have been published in Cell Metabolism.

̽��ֱ��baby’s genes controlled by the father tend to promote fetal growth and those controlled by the mother tend to limit fetal growth.

Professor Sferruzzi-Perri explained: “Those genes from the mother that limit fetal growth are thought to be a mother’s way of ensuring her survival, so she doesn’t have a baby that takes all the nutrients and is too big and challenging to birth. ̽��ֱ��mother also has a chance of having subsequent pregnancies potentially with different males in the future to pass on her genes more widely.”

Researchers deleted the expression of an important imprinted gene called Igf2, which provides instructions for making a protein called ‘Insulin Like Growth Factor 2’. Similar to the hormone insulin, which is responsible for making and controlling glucose levels in our circulation, the gene promotes fetal growth and plays a key part in the development of fetal tissues including the placenta, liver and brain.

Dr Jorge Lopez-Tello, a lead author of the study based at the ̽��ֱ��’s Department of Physiology, Development and Neuroscience, said: “If the function of Igf2 from the father is switched off in signalling cells, the mother doesn’t make enough amounts of glucose and lipids – fats – available in her circulation. These nutrients therefore reach the fetus in insufficient amounts and the fetus doesn’t grow properly.”

̽��ֱ��scientists found that deleting Igf2 from the placenta’s signalling cells affects the production of other hormones that modulate the way the mother’s pancreas produces insulin, and how her liver and other metabolic organs respond.

“We found Igf2 controls the hormones responsible for reducing insulin sensitivity in the mother during pregnancy. It means the mother’s tissues don’t absorb glucose so nutrients are more available in the circulation to be transferred to the fetus,” said Professor Sferruzzi-Perri.

Babies with Igf2 gene defects can be overgrown or growth-stunted. “Until now, we didn’t know that part of the Igf2 gene’s role is to regulate signalling to the mother to allocate nutrients to the fetus,” added Professor Sferruzzi-Perri.

̽��ֱ��mice studied were smaller at birth and their offspring showed early signs of diabetes and obesity in later life.

Professor Sferruzzi-Perri said: “Our research highlights how important the controlled allocation of nutrients to the fetus is for the lifelong health of the offspring, and the direct role the placenta plays.

“ ̽��ֱ��placenta is an amazing organ. At the end of pregnancy, the placenta is delivered by the mother, but the memories of how the placenta was functioning leaves a lasting legacy on the way those fetal organs have developed and then how they’re going to function through life.”

̽��ֱ��next step is to understand how placental hormones are controlled by Igf2 and what those hormones are doing. Future research could help scientists discover new strategies to target the placenta to improve health outcomes for mums and babies.

Mice are used in research because the organisation of their DNA and their gene expression is similar to humans, with ninety-eight percent of human genes having a comparable gene in the mouse. They have similar reproductive and nervous systems to humans, and suffer from many of the same diseases such as obesity, cancer and diabetes.

Reference
Lopez-Tello, J et al. Fetal manipulation of maternal metabolism is a critical function of the imprinted Igf2 gene. Cell Metabolism; 11 July 2023; DOI: 10.1016/j.cmet.2023.06.007

Adapted from a press release from St John’s College Cambridge

A study in mice has found that fetuses use a copy of a gene inherited from their dad to force their mum to release as much nutrition as possible during pregnancy.

It’s the first direct evidence that a gene inherited from the father is signalling to the mother to divert nutrients to the fetus

Amanda Sferruzzi-Perri

Understanding Animal Research

Brown mouse

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Human embryo-like models created from stem cells to understand earliest stages of human development

cjb250 — Tue, 27 Jun 2023 15:00:04 +0000

Published today in the journal Nature, this embryo model is an organised three-dimensional structure derived from pluripotent stem cells that replicate some developmental processes that occur in early human embryos.

Use of such models allows experimental modelling of embryonic development during the second week of pregnancy. They can help researchers gain basic knowledge of the developmental origins of organs and specialised cells such as sperm and eggs, and facilitate understanding of early pregnancy loss.

“Our human embryo-like model, created entirely from human stem cells, gives us access to the developing structure at a stage that is normally hidden from us due to the implantation of the tiny embryo into the mother’s womb,” said Professor Magdalena Zernicka-Goetz in the ̽��ֱ�� of Cambridge’s Department of Physiology, Development and Neuroscience, who led the work.

She added: “This exciting development allows us to manipulate genes to understand their developmental roles in a model system. This will let us test the function of specific factors, which is difficult to do in the natural embryo.”

In natural human development, the second week of development is an important time when the embryo implants into the uterus. This is the time when many pregnancies are lost.

̽��ֱ��new advance enables scientists to peer into the mysterious ‘black box’ period of human development – usually following implantation of the embryo in the uterus – to observe processes never directly observed before.

Understanding these early developmental processes holds the potential to reveal some of the causes of human birth defects and diseases, and to develop tests for these in pregnant women.

Until now, the processes could only be observed in animal models, using cells from zebrafish and mice, for example.

Legal restrictions in the UK currently prevent the culture of natural human embryos in the lab beyond day 14 of development: this time limit was set to correspond to the stage where the embryo can no longer form a twin.

Until now, scientists have only been able to study this period of human development using donated human embryos. This advance could reduce the need for donated human embryos in research.

Zernicka-Goetz says the while these models can mimic aspects of the development of human embryos, they cannot and will not develop to the equivalent of postnatal stage humans.

Over the past decade, Zernicka-Goetz’s group in Cambridge has been studying the earliest stages of pregnancy, in order to understand why some pregnancies fail and some succeed.

In 2021 and then in 2022 her team announced in Developmental Cell, Nature and Cell Stem Cell journals that they had finally created model embryos from mouse stem cells that can develop to form a brain-like structure, a beating heart, and the foundations of all other organs of the body.

̽��ֱ��new models derived from human stem cells do not have a brain or beating heart, but they include cells that would typically go on to form the embryo, placenta and yolk sac, and develop to form the precursors of germ cells (that will form sperm and eggs).

Many pregnancies fail at the point when these three types of cells orchestrate implantation into the uterus begin to send mechanical and chemical signals to each other, which tell the embryo how to develop properly.

There are clear regulations governing stem cell-based models of human embryos and all researchers doing embryo modelling work must first be approved by ethics committees. Journals require proof of this ethics review before they accept scientific papers for publication. Zernicka-Goetz’s laboratory holds these approvals.

“It is against the law and FDA regulations to transfer any embryo-like models into a woman for reproductive aims. These are highly manipulated human cells and their attempted reproductive use would be extremely dangerous,” said Dr Insoo Hyun, Director of the Center for Life Sciences and Public Learning at Boston’s Museum of Science and a member of Harvard Medical School’s Center for Bioethics.

Zernicka-Goetz also holds position at the California Institute of Technology and is NOMIS Distinguished Scientist and Scholar Awardee.

̽��ֱ��research was funded by the Wellcome Trust and Open Philanthropy.

Reference
Weatherbee, B A T et al.: A model of the post-implantation human embryo derived from pluripotent stem cells. Nature; 27 June 2023. DOI: 10.1038/s41586-023-06368-y

Cambridge scientists have created a stem cell-derived model of the human embryo in the lab by reprogramming human stem cells. ̽��ֱ��breakthrough could help research into genetic disorders and in understanding why and how pregnancies fail.

Our human embryo-like model gives us access to the developing structure at a stage that is normally hidden from us due to the implantation of the tiny embryo into the mother’s womb

Magdalena Zernicka-Goetz

̽��ֱ�� of Cambridge

Day 4 embryoid showing an inner epiblast like domain in magenta that has apico-basal polarity (yellow apical, blue basal), similar to the epiblast of the human embryo just after implantation

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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