Project description:We found that the hepatocyte proliferation wave initiated from zone 1/2 to zone 2/3 during early-to-late pregnancy, resulting in the generation of most new hepatocytes in zone 2. By single-cell RNA sequencing, we identified that Ccnd1 was highly enriched in zone 2.
Project description:Disease activity of autoimmune disorders such as multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE) is temporarily suppressed by pregnancy. However, whether disease amelioration is due to non-specific immunomodulation or mediated by antigen-specific regulation of disease-causing conventional T cells (Tcon) and immuno- suppressive regulatory T cells (Treg), remains elusive. In the present study, we systematically analyzed changes of the T cell receptor (TCR) β repertoire driven by EAE and pregnancy using TCR sequencing. We demonstrate that EAE, but not pregnancy, robustly increased TCR repertoire clonality in both peripheral Tcon and Treg. Notably, pregnancy was required for the expansion of Treg harboring the dominant EAE-associated TRBV chain 13.2 and increased the frequency of EAE-associated clonotypes within the Treg compartment. Our findings indicate that pregnancy supports the expansion of Treg clonotypes that are equipped to recognize EAE- associated antigens. These Treg are thereby particularly suited to control corresponding encephalitogenic Tcon responses and likely contribute to pregnancy-associated protection in autoimmunity.
Project description:Infertility and subfertility represent major problems in domestic animals and humans, and the majority of embryonic loss occurs during the first month of gestation that involves pregnancy recognition and conceptus implantation. The critical genes and physiological pathways in the endometrium that mediate pregnancy establishment and success are not well understood. In Study One, 270 predominantly Angus heifers were classified based on fertility using four rounds of serial embryo transfer (ET) to select animals with intrinsic differences in pregnancy loss. In each round, a single in vitro-produced high-quality embryo was transferred into heifers on day 7 post-estrus and pregnancy was determined on days 28 and 42 by ultrasound and then terminated. Heifers were classified based on pregnancy success as high fertile (HF), subfertile (SF), or infertile (IF). In Study Two, fertility-classified heifers were resynchronized and bred with semen from a single high fertility bull. Blood samples were collected every other day from days 0 to 36 post-mating. Pregnancy rate was determined on day 28 by ultrasound and tended to be higher in HF (70.4%) and SF (46.7%) than IF (0%) heifers. Progesterone concentrations in serum during the first 20 days post-estrus were not different in non-pregnant heifers and also not different in pregnant heifers among fertility groups. In Study Three, a single in vivo-produced embryo was transferred into fertility-classified heifers on day 7 post-estrus. The uteri were flushed on day 14 to recover embryos, and endometrial biopsies were obtained from the ipsilateral uterine horn. Embryo recovery rate and conceptus length and area were not different among the heifer groups. RNA was sequenced from the day 14 endometrial biopsies of pregnant HF, SF and IF heifers (n=5 per group) and analyzed by edgeR robust analysis. There were 26 differentially expressed genes (DEG) in the HF compared to SF endometrium, 12 DEG for SF compared to IF endometrium, and 3 DEG between the HF and IF endometrium. Many of the DEG encoded proteins involved in immune responses and are expressed in B cells. Results indicate that pre-implantation conceptus survival and growth to day 14 is not compromised in SF and IF heifers. Thus, the observed difference in capacity for pregnancy success in these fertility-classified heifers is manifest between days 14 and 28 when pregnancy recognition signaling and conceptus implantation must occur for the establishment of pregnancy. Endometrial biopsies were subjected to RNA sequencing from high fertile (HF; n=5), subfertile (SF; n=5) and infertile (IF; n=5) classified heifers on day 14 of pregnancy.
Project description:Background & Aims: Mouse models of lineage tracing have helped to describe the important
subpopulations of hepatocytes responsible for liver regeneration. However, conflicting results have been obtained from different models. Here we aimed to reconcile these conflicting reports by repeating a key lineage tracing study from pericentral hepatocytes and characterised this Axin2CreERT2 model in detail.
Methods: We performed detailed characterisation of the labelled population in the Axin2CreERT2 model. We lineage traced this cell population, quantifying the labelled population over 1 year and performed in depth phenotypic comparison including transcriptomics, metabolomics and analysis of protein through immunohistochemistry of Axin2CreERT2 mice to WT counterparts.
Results: We find that after careful definition of a baseline population there is marked differences in labelling between male and female mice. Upon induced lineage tracing there was no expansion of the labelled hepatocyte population in Axin2CreERT2 mice. We find substantial evidence of disrupted homeostasis in Axin2CreERT2 mice. Offspring are born with sub-Mendelian ratios and adult mice have perturbations of hepatic Wnt/b-catenin signalling and related metabolomic disturbance.
Conclusions: We find no evidence of predominant expansion of the pericentral hepatocyte population during liver homeostatic regeneration. Our data highlight the importance of detailed preclinical model characterisation and the pitfalls which may occur when comparing across sexes and backgrounds of mice and the effects of genetic insertion into native loci.
Project description:Infertility and subfertility represent major problems in domestic animals and humans, and the majority of embryonic loss occurs during the first month of gestation that involves pregnancy recognition and conceptus implantation. The critical genes and physiological pathways in the endometrium that mediate pregnancy establishment and success are not well understood. In Study One, 270 predominantly Angus heifers were classified based on fertility using four rounds of serial embryo transfer (ET) to select animals with intrinsic differences in pregnancy loss. In each round, a single in vitro-produced high-quality embryo was transferred into heifers on day 7 post-estrus and pregnancy was determined on days 28 and 42 by ultrasound and then terminated. Heifers were classified based on pregnancy success as high fertile (HF), subfertile (SF), or infertile (IF). In Study Two, fertility-classified heifers were resynchronized and bred with semen from a single high fertility bull. Blood samples were collected every other day from days 0 to 36 post-mating. Pregnancy rate was determined on day 28 by ultrasound and tended to be higher in HF (70.4%) and SF (46.7%) than IF (0%) heifers. Progesterone concentrations in serum during the first 20 days post-estrus were not different in non-pregnant heifers and also not different in pregnant heifers among fertility groups. In Study Three, a single in vivo-produced embryo was transferred into fertility-classified heifers on day 7 post-estrus. The uteri were flushed on day 14 to recover embryos, and endometrial biopsies were obtained from the ipsilateral uterine horn. Embryo recovery rate and conceptus length and area were not different among the heifer groups. RNA was sequenced from the day 14 endometrial biopsies of pregnant HF, SF and IF heifers (n=5 per group) and analyzed by edgeR robust analysis. There were 26 differentially expressed genes (DEG) in the HF compared to SF endometrium, 12 DEG for SF compared to IF endometrium, and 3 DEG between the HF and IF endometrium. Many of the DEG encoded proteins involved in immune responses and are expressed in B cells. Results indicate that pre-implantation conceptus survival and growth to day 14 is not compromised in SF and IF heifers. Thus, the observed difference in capacity for pregnancy success in these fertility-classified heifers is manifest between days 14 and 28 when pregnancy recognition signaling and conceptus implantation must occur for the establishment of pregnancy.
Project description:We found that in rodents, b-cell mass expansion during pregnancy and obesity is associated with changes in the expression of a group of islet microRNAs. We were able to reproduce in isolated pancreatic islets the decrease of miR-338-3p level observed in gestation and obesity by activating the G-protein coupled estrogen receptor GPR30 and the GLP1 receptor. Blockade of miR-338-3p in b-cells using specific anti-miR molecules mimicked gene expression changes occurring during b-cell mass expansion and resulted in increased proliferation and improved survival both in vitro and in vivo. These findings point to a major role for miR-338-3p in compensatory b-cell mass expansion occurring under different insulin resistance states.
Project description:During pregnancy, pancreatic islets undergo structural and functional changes that lead to enhance insulin release in response to increased insulin demand, which is rapidly reversed at parturition. One of the most important changes is expansion of pancreatic β-cell mass mainly by increased proliferation of β cells. We used microarrays to detail the global programme of gene expression and identified distinct up- or down-regulated genes during pregnancy. Maternal islet were isolated from mice at dpc 0 and 12.5 dpc of pregnancy for RNA extraction and hybridization on Affymetrix microarrays. We sought to identify the responsible factors for the proliferation of islets during pregnancy.
Project description:Transplantation of genetically corrected hepatocytes is an attractive alternative to liver transplantation but is hampered by the low amplification potential of these cells in vitro. Here, we describe a method for generating proliferative hepatic progenitor cells (iHPC) from human hepatocytes as an expandable cell source for liver therapy. Dedifferentiation of primary hepatocytes to iHPC was achieved in less than 7 days by culturing the cells in medium with a cocktail of growth factors and small molecules. In culture, iHPC expressed a combination of endoderm hepatic progenitor and mesenchymal stem cell markers and proliferated vigorously, allowing for their expansion by at least 104 times. RNA sequencing of iHPC demonstrated that they displayed far more subtle changes in both transcriptome and transposcriptome, compared to hepatocyte-derived iPSC. Finally, transplantation of iHPC into the liver of immuno-deficient mice showed iHPC differentiation potential in vivo, without triggering detectable tumor development.
Project description:Transplantation of genetically corrected hepatocytes is an attractive alternative to liver transplantation but is hampered by the low amplification potential of these cells in vitro. Here, we describe a method for generating proliferative hepatic progenitor cells (iHPC) from human hepatocytes as an expandable cell source for liver therapy. Dedifferentiation of primary hepatocytes to iHPC was achieved in less than 7 days by culturing the cells in medium with a cocktail of growth factors and small molecules. In culture, iHPC expressed a combination of endoderm hepatic progenitor and mesenchymal stem cell markers and proliferated vigorously, allowing for their expansion by at least 104 times. RNA sequencing of iHPC demonstrated that they displayed far more subtle changes in both transcriptome and transposcriptome, compared to hepatocyte-derived iPSC. Finally, transplantation of iHPC into the liver of immuno-deficient mice showed iHPC differentiation potential in vivo, without triggering detectable tumor development.