Experimental approaches to derive CD34+ progenitors from human and nonhuman primate embryonic stem cells

Traditionally, CD34 positive cells are predominantly found in the umbilical cord and bone marrow, thus are considered as hematopoietic progenitors. Increasing evidence has suggested that the CD34+ cells represent a distinct subset of cells with enhanced progenitor activity; CD34 is a general marker of progenitor cells in a variety of cell types. Because the CD34 protein shows expression early on in hematopoietic and vascular-associated tissues, CD34+ cells have enormous potential as cellular agents for research and for clinical cell transplantation. Directed differentiation of embryonic stem cells will give rise to an inexhaustible supply of CD34+ cells, creating an exciting approach for biomedical research and for regenerative medicine. Here, we review the main methods that have been published for the derivation of CD34+ cells from embryonic stem cells; specifically those approaches the human and nonhuman primate stem cells. We summarize current status of this field, compare the methods used, and evaluate the issues in translating the bench science to bedside therapy

Differential Expression of Intestinal Genes in Opossums with High and Low Responses to Dietary Cholesterol

High and low responding opossums (Monodelphis domestica) differ in their plasma very low density lipoprotein and low density lipoprotein (VLDL+LDL) cholesterol concentrations when they consume a high cholesterol diet, which is due in part to absorption of a higher percentage of dietary cholesterol in high responders. We compared the expression of a set of genes that influence cholesterol absorption in high and low responders fed a basal or a high cholesterol and low fat (HCLF) diet. Up-regulation of the ABCG5, ABCG8, and IBABP genes by the HCLF diet in high and low responders may reduce cholesterol absorption to maintain cholesterol homeostasis. Differences in expression of the phospholipase genes (PLA2 and PLB) and phospholipase activity were associated with differences in cholesterol absorption when opossums were fed cholesterol-enriched diets. Higher PLA2 and PLB mRNA levels and higher phospholipase activity may increase cholesterol absorption in high responders by enhancing the release of cholesterol from bile salt micelles for uptake by intestinal cells

A preliminary timeline of the midbrain development in the Monodelphis Domestica animal model

Introduction: The Brazilian short-tailed opossum (Monodelphis Domestica) is an understudied animal model compared to the Mus musculus that has been identified as a perfect candidate to study neurodevelopment (Baggott, L. & Moore, H., 1990). What makes the Monodelphis Domestica a perfect specimen for neurodevelopment is that the embryo develops outside the pouch of the mother providing easy noninvasive access to track changes across different developmental stages (Mate et al., 1994). Objective: The objective of the study is to compare the area and volume in the development of the Monodelphis’s midbrain across three different developmental stages. Our research is beneficial because it facilitates the study of neurodevelopmental mental health disorders and its impact in the brain. Methods: We utilized ImageJ and Zen software to perform the volumetric and area analysis of these stages. To conduct a volumetric analysis a Volume Macro code was used in ImageJ software. The area analysis was completed using Zen software. A descriptive analysis was used to compare the differences in area and volume across the developmental stages

Language in the Mind's Eye: Visual Representations and Language Processing

My favorite children’s book was (and still is) Matilda, by Roald Dahl. The story is about Matilda Wormwood, an extraordinarily clever and sweet five year old girl who loves to learn and read. Unfortunately, her unpleasant parents are contemptuous of her inquisitiveness and talent, as is the headmistress of her school, Miss Trunchbull. While Matilda’s parents force her to eat microwave dinners and watch loud game shows on TV, the child-hating Miss Trunchbull sows fear by locking children up in a device called the Chokey (a claustrophobic closet with spikes perforating the walls) or launching them across the schoolyard after swirling them around by their braids. Then, Matilda finds out she has psychokinetic powers and decides to use them to teach her parents and headmistress a lesson. The magic of this book was that it made me feel like being drawn away from reality and into Matilda’s world: I could feel her eagerness to learn and her frustration with her parents, I could see her father’s face and hear him shouting when she super-glued his hat to his head, and I envisioned what it looked like when she used her special powers to make crayons fly and write messages on a chalkboard to scare the life out of Miss Trunchbull. How is this possible? How can abstract symbols such as letters and words on a page come to life, engage you, create vivid images, and make you feel like you experience the described events yourself

A Neural Comparison Between Mus Musculus and Monodelphis Domestica

Mus Musculus is one of the first and widely used animal models in neuroscience. There are many reasons that Mus Musculus is used for research including, short generation length and large litters, but the most important reason is their mammalian brain. Another animal that is gaining interest as an animal model is the Monodelphis Domestica. The Monodelphis Domestica is a marsupial, pups are born underdeveloped and move onto the underbelly of their mothers until they reach a more mature age. One difference is the Monodelphis ventricle size is much larger in the forebrain area. Another difference is the formation of the corpus callosum. In the mouse brain, the corpus callosum forms and fuses before the hippocampus compared to the possum where the corpus callosum is formed more posterior to the formation of the hippocampus. The corpus callosum of the Monodelphis is less prominent than the anterior commissure. In the mouse brain, the majority of the nerve fibers are found in the corpus callosum as opposed to the anterior commissure. The corpus callosum allows communication between both hemispheres of the brain. In the mus musculus, the hippocampus is well defined and begins formation after the formation of the corpus callosum. In the Monodelphis, the hippocampus is not as defined. The mus musculus is a social animal, the more defined hippocampus could be an evolutionary improvement for social interaction. The Monodelphis is a more territorial and isolated species. Looking at the differences between the two, can further knowledge into the behavioral differences

Vertebrate endothelial lipase: comparative studies of an ancient gene and protein in vertebrate evolution

Endothelial lipase (gene: LIPG; enzyme: EL) is one of three members of the triglyceride lipase family that contributes to lipoprotein degradation within the circulation system and plays a major role in HDL metabolism in the body. In this study, in silico methods were used to predict the amino acid sequences, secondary and tertiary structures, and gene locations for LIPG genes and encoded proteins using data from several vertebrate genome projects. LIPG is located on human chromosome 18 and is distinct from other human 'neutral lipase' genes, hepatic lipase (gene: LIPC; enzyme: HL) and lipoprotein lipase (gene: LPL; enzyme: LPL) examined. Vertebrate LIPG genes usually contained 10 coding exons located on the positive strand for most primates, as well as for horse, bovine, opossum, platypus and frog genomes. The rat LIPG gene however contained only 9 coding exons apparently due to the presence of a 'stop' codon' within exon 9. Vertebrate EL protein subunits shared 58-97% sequence identity as compared with 38-45% sequence identities with human HL and LPL. Four previously reported human EL N-glycosylation sites were predominantly conserved among the 10 potential N-glycosylation sites observed for the vertebrate EL sequences examined. Sequence alignments and identities for key EL amino acid residues were observed as well as conservation of predicted secondary and tertiary structures with those previously reported for horse pancreatic lipase (PL) (Bourne et al. 1994). Several potential sites for regulating LIPG gene expression were observed including CpG islands near the LIPG gene promoter and a predicted microRNA binding site near the 3'-untranslated region. Promoter regions containing functional polymorphisms that regulate HDL cholesterol in baboons were conserved among primates but not retained between primates and rodents. Phylogenetic analyses examined the relationships and potential evolutionary origins of the vertebrate LIPG gene subfamily with other neutral triglyceride lipase gene families, LIPC and LPL. It is apparent that the triglyceride lipase ancestral gene for the vertebrate LIPG gene predated the appearance of fish during vertebrate evolution[500 million years ago.Full Tex

Investigating Monodelphis Domestica as an Alternative to the Mus Musculus as an Animal Model

Background: Mus Musculus is one of the first and one of the most widely used animal models in current neuroscience literature (Phifer-Riley & Nachmann, 2015). However, the research community needs alternatives to rodent models to study the mammalian brain. Research is needed to see if antibodies that target tyrosine hydroxylase, which are well researched in mice, can also be used to study the Monodelphis domestica brain. Methods: Following transcardial perfusions and brain extractions, mouse and opossum brains were processed and stained for tyrosine hydroxylase (and with Nissl). Opossum brains will then be sliced and processed using IHC methods to compare two TH antibodies (EMD Millipore and Pelfreeze). Results: Differences include that the Monodelphis has a much larger ventricle in the forebrain area and the mouse brain corpus callosum forms and fuses before the hippocampus compared to the opossum brain, where these fibers are formed more posterior to the formation of the hippocampus. The corpus callosum of the Monodelphis is also less prominent than the anterior commissure. The results of the different antibodies will be presented at the symposium. Conclusions: Although there are differences between the mouse and the opossum brain, there are also many similarities. Further research is needed to determine what these differences could mean in behavior and cognition. Both EMD Millipore and Pelfreeze make TH antibodies that have been looked at in mice and replicated. More research is needed to determine if the antibodies can be used for other animals, including the Monodelphis