scholarly journals Liver development is restored by blastocyst complementation of HHEX knockout in mice and pigs

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
M. Ruiz-Estevez ◽  
A. T. Crane ◽  
P. Rodriguez-Villamil ◽  
F. L. Ongaratto ◽  
Yun You ◽  
...  
Keyword(s):  
Gene Expression ◽  
Liver Tissue ◽  
Early Stage ◽  
Significant Loss ◽  
Embryonic Lethality ◽  
Innovative Technology ◽  
Specific Gene ◽  
Liver Development ◽  
Blastocyst Complementation ◽  
Gene And Protein Expression

Abstract Background There are over 17,000 patients in the US waiting to receive liver transplants, and these numbers are increasing dramatically. Significant effort is being made to obtain functional hepatocytes and liver tissue that can for therapeutic use in patients. Blastocyst complementation is a challenging, innovative technology that could fundamentally change the future of organ transplantation. It requires the knockout (KO) of genes essential for cell or organ development in early stage host embryos followed by injection of donor pluripotent stem cells (PSCs) into host blastocysts to generate chimeric offspring in which progeny of the donor cells populate the open niche to develop functional tissues and organs. Methods The HHEX gene is necessary for proper liver development. We engineered loss of HHEX gene expression in early mouse and pig embryos and performed intraspecies blastocyst complementation of HHEX KO embryos with eGFP-labeled PSCs in order to rescue the loss of liver development. Results Loss of HHEX gene expression resulted in embryonic lethality at day 10.5 in mice and produced characteristics of lethality at day 18 in pigs, with absence of liver tissue in both species. Analyses of mouse and pig HHEX KO fetuses confirmed significant loss of liver-specific gene and protein expression. Intraspecies blastocyst complementation restored liver formation and liver-specific proteins in both mouse and pig. Livers in complemented chimeric fetuses in both species were comprised of eGFP-labeled donor-derived cells and survived beyond the previously observed time of HHEX KO embryonic lethality. Conclusions This work demonstrates that loss of liver development in the HHEX KO can be rescued via blastocyst complementation in both mice and pigs. This complementation strategy is the first step towards generating interspecies chimeras for the goal of producing human liver cells, tissues, and potentially complete organs for clinical transplantation.

Global Transcriptomic Analysis During Murine Pneumonia Infection Reveals New Virulence Factors in Acinetobacter baumannii

2020 ◽  
Author(s):  
Marta Martínez-Guitián ◽  
Juan C Vázquez-Ucha ◽  
Laura Álvarez-Fraga ◽  
Kelly Conde-Pérez ◽  
Juan A Vallejo ◽  
...  
Keyword(s):  
Gene Expression ◽  
Acinetobacter Baumannii ◽  
Gene Expression Profile ◽  
Expression Profile ◽  
Iron Acquisition ◽  
Significant Loss ◽  
Transcriptomic Analysis ◽  
Specific Gene ◽  
Major Health Problem

Abstract Background Infections caused by multidrug-resistant pathogens such as Acinetobacter baumannii constitute a major health problem worldwide. In this study we present a global in vivo transcriptomic analysis of A. baumannii isolated from the lungs of mice with pneumonia infection. Methods Mice were infected with A. baumannii ATCC 17978 and AbH12O-A2 strains and the total bacterial RNA were analyzed by RNA sequencing. Lists of differentially expressed genes were obtained and 14 of them were selected for gene deletion and further analysis. Results Transcriptomic analysis revealed a specific gene expression profile in A. baumannii during lung infection with upregulation of genes involved in iron acquisition and host invasion. Mutant strains lacking feoA, mtnN, yfgC, basB, hisF, oatA, and bfnL showed a significant loss of virulence in murine pneumonia. A decrease in biofilm formation, adherence to human epithelial cells, and growth rate was observed in selected mutants. Conclusions This study provides an insight into A. baumannii gene expression profile during murine pneumonia infection. Data revealed that 7 in vivo upregulated genes were involved in virulence and could be considered new therapeutic targets.

Transcriptional alterations in the left ventricle of three hypertensive rat models

2006 ◽  
Vol 27 (3) ◽  
pp. 295-308 ◽  
Author(s):  
Catherine Cerutti ◽  
Mazen Kurdi ◽  
Giampiero Bricca ◽  
Wassim Hodroj ◽  
Christian Paultre ◽  
...  
Keyword(s):  
Gene Expression ◽  
Genetic Background ◽  
Spontaneously Hypertensive Rat ◽  
Early Stage ◽  
Gene Expression Pattern ◽  
Left Ventricular ◽  
Cardiac Cells ◽  
Specific Gene ◽  
Expression Data ◽  
Hypertensive Rat

Left ventricular hypertrophy (LVH) is commonly associated with hypertension and represents an independent cardiovascular risk factor. The aim of this study was to test the hypothesis that the cardiac overload related to hypertension is associated to a specific gene expression pattern independently of genetic background. Gene expression levels were obtained with microarrays for 15,866 transcripts from RNA of left ventricles from 12-wk-old rats of three hypertensive models [spontaneously hypertensive rat (SHR), Lyon hypertensive rat (LH), and heterozygous TGR(mRen2)27 rat] and their respective controls. More than 60% of the detected transcripts displayed significant changes between the three groups of normotensive rats, showing large interstrain variability. Expression data were analyzed with respect to hypertension, LVH, and chromosomal distribution. Only four genes had significantly modified expression in the three hypertensive models among which a single gene, coding for sialyltransferase 7A, was consistently overexpressed. Correlation analysis between expression data and left ventricular mass index (LVMI) over all rats identified a larger set of genes whose expression was continuously related with LVMI, including known genes associated with cardiac remodeling. Positioning the detected transcripts along the chromosomes pointed out high-density regions mostly located within blood pressure and cardiac mass quantitative trait loci. Although our study could not detect a unique reprogramming of cardiac cells involving specific genes at early stage of LVH, it allowed the identification of some genes associated with LVH regardless of genetic background. This study thus provides a set of potentially important genes contained within restricted chromosomal regions involved in cardiovascular diseases.

scholarly journals In situ quantification of individual mRNA transcripts in melanocytes discloses gene regulation of relevance to speciation

2018 ◽  
Author(s):  
Chi-Chih Wu ◽  
Axel Klaesson ◽  
Julia Buskas ◽  
Petter Ranefall ◽  
Reza Mirzazadeh ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Molecular Basis ◽  
Early Stage ◽  
Rolling Circle Amplification ◽  
Natural Populations ◽  
Specific Gene ◽  
Pigment Synthesis ◽  
Rolling Circle ◽  
Mrna Transcripts

AbstractFunctional validation of candidate genes for adaptation and speciation remains challenging. We here exemplify the utility of a method quantifying individual mRNA transcripts in revealing the molecular basis of divergence in feather pigment synthesis during early-stage speciation in crows. Using a padlock probe assay combined with rolling circle amplification we quantified cell-type specific gene expression in the native, histological context of growing feather follicles. Expression of Tyrosinase related protein 1 (TYRP1), Solute carrier family 45 member 2 (SLC45A2) and Hematopoietic prostaglandin D synthase (HPGDS) was melanocyte-limited and significantly reduced in follicles from hooded crow explaining the substantially lower melanin content in grey vs. black feathers. The central upstream transcription factor Microphthalmia-associated transcription factor (MITF) only showed differential expression specific to melanocytes - a feature not captured by bulk RNA-seq. Overall, this study provides insight into the molecular basis of an evolutionary young transition in pigment synthesis, and demonstrates the power of histologically explicit, statistically substantiated single-cell gene expression quantification for functional genetic inference in natural populations.

scholarly journals Transient Reprogramming of Neonatal Cardiomyocytes to a Proliferative Dedifferentiated State

2019 ◽  
Author(s):  
Thomas Kisby ◽  
Irene de Lázaro ◽  
Maria Stylianou ◽  
Giulio Cossu ◽  
Kostas Kostarelos
Keyword(s):  
Gene Expression ◽  
Culture Media ◽  
Contractile Activity ◽  
Biological Effects ◽  
Embryonic Stem ◽  
Neonatal Rat ◽  
Specific Gene ◽  
Specific Cell ◽  
Rat Cardiomyocytes ◽  
Gene And Protein Expression

AbstractZebrafish and urodele amphibians are capable of extraordinary myocardial regeneration thanks to the ability of their cardiomyocytes to undergo transient dedifferentiation and proliferation. Somatic cells can be temporarily reprogrammed to a proliferative, dedifferentiated state through transient expression of Oct3/4, Sox2, Klf4 and c-Myc (OSKM) transcription factors. Here, we utilized an OSKM-encoding non-integrating vector to induce transient reprogramming of mammalian cardiomyocytes in vitro. Reprogramming factor expression in neonatal rat cardiomyocytes triggered rapid cell dedifferentiation characterized by downregulation of cardiomyocyte specific gene and protein expression, sarcomere dis-assembly and loss of autorhythmic contractile activity. Concomitantly, a significant increase in cell cycle related gene expression and Ki67 positive cells was observed, indicating that dedifferentiated cardiomyocytes possess an enhanced proliferative capacity. A small proportion of cardiomyocytes progressed through mesenchymal to epithelial transition, further indicating the initiation of cell reprogramming. However, complete reprogramming to a pluripotent-like state was not achieved for the duration of the study (20 days), both in standard and embryonic stem cell culture media conditions. The transient nature of this partial reprogramming response was confirmed as cardiomyocyte-specific cell morphology, gene expression and contractile activity were recovered by day 15 after viral transduction. Further investigations into the complete downstream biological effects of ectopic OSKM expression in cardiomyocytes and the fate of these reprogrammed cells are warranted. Our results to date suggest that transient reprogramming could be a feasible strategy to recapitulate regenerative mechanisms of lower vertebrates and inform direct gene therapy approaches to cardiac regenerative medicine.

scholarly journals Investigating Both Mucosal Immunity and Microbiota in Response to Gut Enteritis in Yellowtail Kingfish

2020 ◽  
Vol 8 (9) ◽  
pp. 1267
Author(s):  
Thibault P. R. A. Legrand ◽  
James W. Wynne ◽  
Laura S. Weyrich ◽  
Andrew P. A. Oxley
Keyword(s):  
Gene Expression ◽  
Sequence Data ◽  
Early Stage ◽  
Significant Loss ◽  
Differentially Expressed ◽  
Gastrointestinal Microbiota ◽  
Health States ◽  
Gut Inflammation ◽  
Mucosal Surfaces ◽  
Yellowtail Kingfish

The mucosal surfaces of fish play numerous roles including, but not limited to, protection against pathogens, nutrient digestion and absorption, excretion of nitrogenous wastes and osmotic regulation. During infection or disease, these surfaces act as the first line of defense, where the mucosal immune system interacts closely with the associated microbiota to maintain homeostasis. This study evaluated microbial changes across the gut and skin mucosal surfaces in yellowtail kingfish displaying signs of gut inflammation, as well as explored the host gene expression in these tissues in order to improve our understanding of the underlying mechanisms that contribute to the emergence of these conditions. For this, we obtained and analyzed 16S rDNA and transcriptomic (RNA-Seq) sequence data from the gut and skin mucosa of fish exhibiting different health states (i.e., healthy fish and fish at the early and late stages of enteritis). Both the gut and skin microbiota were perturbed by the disease. More specifically, the gastrointestinal microbiota of diseased fish was dominated by an uncultured Mycoplasmataceae sp., and fish at the early stage of the disease showed a significant loss of diversity in the skin. Using transcriptomics, we found that only a few genes were significantly differentially expressed in the gut. In contrast, gene expression in the skin differed widely between health states, in particular in the fish at the late stage of the disease. These changes were associated with several metabolic pathways that were differentially expressed and reflected a weakened host. Altogether, this study highlights the sensitivity of the skin mucosal surface in response to gut inflammation.

scholarly journals Threshold Levels of Hepatocyte Nuclear Factor 6 (HNF-6) Acting in Synergy with HNF-4 and PGC-1α Are Required for Time-Specific Gene Expression during Liver Development

2006 ◽  
Vol 26 (16) ◽  
pp. 6037-6046 ◽  
Author(s):  
Jean-Bernard Beaudry ◽  
Christophe E. Pierreux ◽  
Graham P. Hayhurst ◽  
Nicolas Plumb-Rudewiez ◽  
Mary C. Weiss ◽  
...  
Keyword(s):  
Gene Expression ◽  
Specific Gene ◽  
Liver Development ◽  
Nuclear Factor ◽  
Hepatocyte Nuclear Factor ◽  
Loss Of Function ◽  
Specific Expression ◽  
Threshold Levels ◽  
Time Specific

ABSTRACT During liver development, hepatocytes undergo a maturation process that leads to the fully differentiated state. This relies at least in part on the coordinated action of liver-enriched transcription factors (LETFs), but little is known about the dynamics of this coordination. In this context we investigate here the role of the LETF hepatocyte nuclear factor 6 (HNF-6; also called Onecut-1) during hepatocyte differentiation. We show that HNF-6 knockout mouse fetuses have delayed expression of glucose-6-phosphatase (g6pc), which catalyzes the final step of gluconeogenesis and is a late marker of hepatocyte maturation. Using a combination of in vivo and in vitro gain- and loss-of-function approaches, we demonstrate that HNF-6 stimulates endogenous g6pc gene expression directly via a synergistic and interdependent action with HNF-4 and that it involves coordinate recruitment of the coactivator PGC-1α. The expression of HNF-6, HNF-4, and PGC-1α rises steadily during liver development and precedes that of g6pc. We provide evidence that threshold levels of HNF-6 are required to allow synergism between HNF-6, HNF-4, and PGC-1α to induce time-specific expression of g6pc. Our observations on the regulation of g6pc by HNF-6 provide a model whereby synergism, interdependency, and threshold concentrations of LETFs and coactivators determine time-specific expression of genes during liver development.

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