Ensuring quality maternal care in an adverse environment

Lead Research Organisation: Cardiff University


A critically important adaptation during the mammalian pregnancy is the induction of maternal care. Maternal care is vitally important for the survival of the newborn and the withdrawal of maternal care or poor quality maternal care can result in adverse behavioural and metabolic outcomes later in life. Importantly, prenatal adversities such as suboptimal diet or stress can influence the quality of maternal care. Consequently, understanding how maternal care is induced and how the maternal environment influences the induction of maternal care is of paramount importance.

There is some evidence that the placenta plays a role in instructing the mother to care for her newborns. The placenta is a transient organ of pregnancy that plays a key role in transferring nutrients to the growing fetus. The placenta is also a super endocrine organ that manufactures hormones that flood the maternal system to induce the changes required for a successful, health pregnancy. Studies suggest that some of these hormones, the placental lactogens, may induce maternal care. Given this proposed role for the placenta, placental dysfunction could contribute to poor maternal care.

We have identified a gene called Phlda2 that is important for the production of these placental hormones. Phlda2 regulates the amount of placental hormones that are manufactured by regulating the size of the placental endocrine compartment. Transgenic over expression of Phlda2 results in a smaller endocrine compartment. Mouse mothers exposed to placenta with this much smaller endocrine compartment exhibit changes in gene expression and neurogenesis in the maternal brain during pregnancy and poor maternal care of their offspring, even though they themselves are not mutant for Phlda2. Phlda2 is an imprinted gene whose expression is regulated by epigenetic marks. Remarkably, expression of Phlda2 is altered in the placenta in response to the two different suboptimal maternal diets that have previously been linked to poor maternal care. This leads us to believe that a suboptimal maternal diet may contribute to poor maternal care by altering the expression of Phlda2 in the placenta and thus reducing exposure of the maternal brain to placental lactogens. In this study, we will use a variety of existing experimental models and techniques to test this hypothesis first asking whether we can restore maternal care by manipulating placental expression of Phlda2 in a dietary model, and then by exploring the mechanism initially focusing on placental lactogen signaling via the maternal prolactin receptor. We will also develop a novel imaging tool based on infrared luciferase, to ask whether we can longitudinally bioimage ongoing maternal neurogenesis. A considerable advantage of this tool will be the ability to image the same animal multiple times substantially reducing the number of animals required for our studies.
This work is important not just in helping us to fundamentally understand how maternal care is induced but also how this process may be influenced by the maternal environment, and how we might be able to restore maternal care - work that will have wide relevance to the welfare of experimental, domestic and agricultural animals as well as human health.

Technical Summary

Prenatal adversity, specifically diets low in protein or high in fat, have been linked to poor quality maternal care. We have shown that expression of Phlda2 in the placenta can be altered by maternal diet. Phlda2 regulates the expression of placental lactogens. Lactogenic signalling via the maternal prolactin receptor has been implicated in the induction of maternal care in rodents. Dams exposed to Phlda2 mutant placenta display abnormal maternal care. To assess the extent to which elevated placental Phlda2 contributes to abnormal maternal care in response to low protein diet, we will combine maternal low protein with a genetic model in which the elevated expression of Phlda2 from the placenta is prevented by a targeted deletion followed by characterisation using a combination of RNAseq, immunohistochemistry and classic behavioural assays.
In a second aim, we will ask whether we can rescue any aspect of the maternal phenotypes observed independently in prolactin receptor (Prlr) heterozygous knock dams and our dams carrying 2XPhlda2 placenta, which express low levels of placental lactogen, by combining the Prlr receptor heterozygous knockout model (50% receptor) with our 0XPhlda2 placenta (high placental lactogens).
In a third aim, we will use intracerebral ventricular infusion to ask whether we can restore maternal behaviour by a central nervous system infusion of placental lactogen making use of the new iPRECIO programmable infusion pump system. We will also develop a bioimaging system, based on an infrared variant of luciferase, as a quantitative tool to image neurogenesis. The ability to image neurogenesis in vivo, during pregnancy and after delivery, would reduce animal numbers and has the potential transform the research in this area. Overall, this work will identify a novel mechanism linking maternal nutrition to maternal care which will have important implications for the design of interventions aimed at improving maternal care.

Planned Impact

Enhancing quality of life, health and well-being:
While our studies are in rodents, which have very different placenta to humans, they may have some relevance to our understanding of human maternal mood disorders. We have some evidence from our MRC funded study that altered expression of certain imprinted genes in the human placenta is associated with self-reported maternal prenatal depression and clinically diagnosed prenatal depression. Thus if our work in rodents leads to a better understanding of the origins of maternal mood disorders, our findings may translate into the human situation to enhance the quality of life. This is particularly important as we are not just studying why maternal care fails but also investigating approaches to restore maternal care in an adverse environment.

The economy:
If our studies translate to humans, our discoveries have the potential to benefit the British economy by reducing costs to the NHS in treating maternal mood disorders and the associated childhood behavioural disorders. According to report by the London School of Economics and Political Science and the Centre for Mental Health in 2014, perinatal mental health problems cost the UK economy >£8 billion each year.

If our studies translate to the other non-human mammals, our work may have relevance to the successful raising and breeding of a number of agricultural, experimental and domestic animals. For example, there is a 15% mortality rate in lambs with an estimated to cost the UK economy >£180M per annum. A very modest 0.5% reduction in mortality rate, potentially by something as simple as a dietary change, would save the UK economy £6M/annum.

Although not the focus of this study, there is the potential for the development of biomarkers, which predict abnormal maternal behaviours, and also suggest therapeutic approaches to treating prenatal depression

Contributing towards evidence based policy-making and influencing public policies and legislation at a local, regional, national and international level:
We have found that expression of Phlda2 is up regulated in the placenta in response to a suboptimal maternal diet in rodents. We have also found a similar increase in expression of PHLDA2 in human placenta obtained from women reporting a high fat diet during pregnancy. Our current work suggests this aberrant expression is relevant to both fetal and maternal health, and childhood wellbeing. Our findings may lead to changes advice given to pregnant women.

Contributing to increasing public awareness and understanding of science, economic and societal issues:
News media play a role in informing the way people understand science. The public understanding of issues such as climate change, stem cells and MMR have increased due to media coverage as a consequence of new discoveries reported in scientific journals. The public is likely to be very interested in our work as it concerns the wellbeing of mothers and their children. Our work will raise awareness of epigenetics and, ultimately the role of the environment early in life in shaping later life outcomes

Enhancing the knowledge economy:
Nothing is published linking Phlda2 to maternal care or childhood outcomes. Our scientific discoveries will provide new knowledge.

Worldwide scientific advancement to address issues of importance in other countries or globally: Studies on Phlda2 may provide a tool to address maternal mental health worldwide.

Delivering and training highly skilled researchers:
This work will provide valuable training to a young researcher and a technician in in vivo models (behavioural neuroscience, bio-imaging), molecular and bioinformatics (RNAseq) skills.


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Description Through this funding we have shown that a gene expressed in the the placental that regulates the number of cells producing placental hormones is vitally important for maternal care in mice. Mouse mothers exposed to mutant placenta with too few hormone-producing cells spend less time nurturing the pups while mouse mothers exposed to placenta with extra hormone-producing cells are highly focused on nursing and grooming their pups, and neglect the "housekeeping" task of nest building. The paper has now been published in Plos Biology in 2018 and already cited 6 time since July. The story was picked up by news media across the world including America, Canada, Australia, Kazakstan, India, Italy, Spain, Poland, Germany and China. A report on our findings was developed for the Biomedical Science Journal for Teens. We have identified a second gene which regulates placental hormone producing cells and showed that this gene can also influence maternal care provision in mice
Exploitation Route There is potential for increased understanding of low birth weight and maternal mood disorders. Elevated Phlda2 causes low birth weight in mice and changes in the behaviour of dams towards their pups. We have previously reported that PHLDA2 is abnormally expressed in the placenta of small for gestational age infants. We are currently examining placental gene expression a human cohort study to ask whether placental endocrine insufficiency contributes to maternal mood disorders.
Sectors Healthcare

URL http://www.cardiff.ac.uk/people/view/81202-john-rosalind
Description Exposing the link between placental endocrine dysfunction and offspring behavioural outcomes
Amount £551,834 (GBP)
Funding ID BB/P008623/1 
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 09/2017 
End 03/2021
Description Imprinted genes as master regulators of placental hormones
Amount £641,220 (GBP)
Funding ID BB/V014765/1 
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 06/2021 
End 06/2024
Title Maternal care boosted by paternal imprinting in mammals 
Description GSE115276: Microarray data from maternal hippocampus and hypothalamus exposed to placental defects in endocrine lineages at E16.5 pf pregnancy 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? Yes  
Impact First demonstration that hormonal signals from the placenta impact the expression of genes in the maternal hypothalamus and hippocampus 
URL https://osf.io/543jg/
Description El Colegio Nacional online seminar "The Maternal Brain: from placentas to care giving behaviour" 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Research-led seminar presented as part of the Universities for Science Consortium which is an international organisation involved in the wider dissemination of research. Research talks are released via facebook and youtube and are publically accessible
Year(s) Of Engagement Activity 2020
URL https://www.youtube.com/watch?v=bVolh1lLsho
Description Media reports on our Plos Biology paper 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact In response to a media release by Plos Biology on our recent paper, we were interviewed by Smithsonian Magazine and the Daily Mail and the story was reported in the media worldwide

Nature Ecology & Evolution (UK)

Phys.org (UK)

Daily Mail (UK)

Genetic Engineering & Biotechnology news highlight (USA)

Smithsonian Magazine (USA)

EurekAlert (USA)

MedicalResearch.com (USA)

Science Daily (USA)

Fatherly (USA)

Xinhuanet (China)

China.org.cn (China)

TheCable (Nigeria)

News-medical (Australia)

India Today (India)

Kazinform (Kazakhstan)

Gazeta Wyborcza (Poland)
Translated "Everything is my father's fault. His genes also control ... maternal love"

Le Scienze (Italy)
"Il gene del feto che influenza le cure materne" The gene of the fetus that influences maternal care

Die Presse (Germany)
"Wie Väter für mehr Mutterliebe sorgen (wollen)"

My Science (Switzerland)

theravive - Mental Health Awareness and Therapist Network (Canada)


Year(s) Of Engagement Activity 2018
URL https://www.smithsonianmag.com/science-nature/how-dads-genes-can-prepare-mom-parenthood-180969793/
Description Podcast 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact I was interviewed by Dr Kat Arney for an episode of Genetics Unzipped, a weekly podcast sponsored by the Genetics Society where I described our work on the placenta, and how placental hormones influence maternal caregiving and offspring behaviour.
Year(s) Of Engagement Activity 2021
URL https://geneticsunzipped.com/blog/2021/10/7/science-genetics-placenta-mother-baby
Description Presentation to A level teachers as part of their continual professionla development 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Schools
Results and Impact Presented a talk on Epigenetics to A level teachers from all over the UK hosted by Wales Gene Park in Cardiff
Year(s) Of Engagement Activity 2017
URL http://www.walesgenepark.cardiff.ac.uk/2017/05/16/teachers-genetics-cpd-events-2/
Description Public Engagement Biology & Geology Rock! 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Presented our research on Healthy Pregnancy to public at National Museum Cardiff "Biology & Geology Rock! " event
Year(s) Of Engagement Activity 2017
URL https://museum.wales/cardiff/whatson/9696/Biology-and-Geology-Rock/
Description Science Journal for Kids 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Schools
Results and Impact Science Journal for Kids presents is an online media that adapts cutting edge peer-reviewed science research for students which has been visited >500,000 times since its conception. School age children and their teachers from all places across the global access this material.
Year(s) Of Engagement Activity 2018
URL https://www.sciencejournalforkids.org/search-articles/how-does-pregnancy-change-mothers-behavior
Description Talk to year 2 student medics 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Undergraduate students
Results and Impact Presented findings from research to Year 2 medical students to increase their exposure to research.
Year(s) Of Engagement Activity 2019
Description Workshop for student midwives 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Undergraduate students
Results and Impact I deliver two School of Healthcare sciences workshops for student midwives. The Year 1 workshop focuses on maternal lifestyles and birth weight. The Year 3 workshop focuses on maternal mood disorders. Students complete questionnaires to demonstrate their gain in knowledge.
Year(s) Of Engagement Activity 2021