Nobuyo Maeda | |
---|---|
Born | Early 1950s Sendai, Miyagi Prefecture, Japan |
Nationality | Japanese |
Education | Tohoku University |
Occupation | Robert H. Wagner Distinguished Professor |
Years active | 1978- |
Known for | Creating the first mouse model for atherosclerosis |
Medical career | |
Institutions | University of North Carolina at Chapel Hill |
Sub-specialties | Genetics, medical research |
Awards | Method to Extend Research in Time (MERIT) Award of the National Heart, Lung, and Blood Institute |
Nobuyo N. Maeda is a Japanese geneticist and medical researcher, who works on complex human diseases including atherosclerosis, diabetes and high blood pressure, and is particularly known for creating the first mouse model for atherosclerosis. Maeda has worked in the United States since 1978; as of 2017, she is the Robert H. Wagner Distinguished Professor at the University of North Carolina at Chapel Hill. [1]
Maeda was born in Sendai, Miyagi Prefecture, Japan in the early 1950s, the second of three sisters. Her father was a chemical engineering professor. [2] She attended Tohoku University in Sendai, where she received a BSc in chemistry (1972) and an MSc in bio-organic chemistry (1974), followed by a PhD in the same subject in 1977; her thesis was entitled "Isolation and characterization of neurotoxins from the venoms of sea snakes, and the use of amino acid sequences in taxonomy". [3]
Maeda first briefly worked in the laboratory of Nobuo Tamiya at the Department of Chemistry of Tohoku University. In 1978, she left Japan for the United States, and worked for a decade at the University of Wisconsin–Madison. She held post-doctoral positions in the laboratories of Walter M. Fitch (Department of Physiological Chemistry; 1978–81) and Oliver Smithies (Laboratory of Genetics; 1981–83), and then worked in the Laboratory of Genetics as an assistant and then associate scientist. [3]
She moved to the Department of Pathology of the University of North Carolina at Chapel Hill in 1988, with her collaborator (and later husband) Smithies, [2] where she held successively positions as associate professor (1988) and professor (1996), and was appointed the Robert H. Wagner Distinguished Professor at the Department of Pathology and Laboratory Medicine in 2003. [3] She is also an adjunct professor in the Department of Nutrition (from 2000) and has directed the university's pre-doctoral training program in vascular biology since 2002. [3] [4]
She was awarded the Method to Extend Research in Time (MERIT) Award of the National Heart, Lung, and Blood Institute (1998). [4]
Maeda's early work on sea snake venoms led to an interest in molecular evolution, which she pursued in Fitch's laboratory. [2] She published in the 1980s on molecular evolution in higher primates such as chimpanzees and humans. [5] Her work focused on the large mutational effects of recombination between members of multigene families, particularly in the human haptoglobin gene cluster. [6]
In 1987, Maeda, Smithies and coworkers used the novel technique of gene targeting – a method of replacing single mouse genes using homologous recombination developed by Smithies, Mario Capecchi and others – to correct the hypoxanthine-guanine phosphoribosyltransferase gene responsible for Lesch–Nyhan syndrome in mouse cells in vitro. [7] [8] This was the second successful use of the technique to be published. [6] [7] Maeda then started to apply gene targeting to elucidate the function of lipoproteins, which had been shown by Jan and Judith Rapacz to be associated with atherosclerosis in domestic pigs. [6] [9] She was one of the first to apply gene-targeting methods to a complex, multifactorial disease, rather than single-gene disorders such as cystic fibrosis and Lesch–Nyhan syndrome. [10] Maeda and her coworkers found that deleting the mouse gene for apolipoprotein E (ApoE) – a component of very low-density lipoprotein – caused the animals to develop elevated blood cholesterol levels and atherosclerosis within around 6 months, on a normal diet. [6] [9] [11] The results were published in 1992, in a highly cited paper in Science . [12] [nb 1] The ApoE knockout (apoe−/−) was the earliest mouse model of the disease, and has been widely used in atherosclerosis research. [11] [14] [15] [nb 2]
Maeda's group subsequently carried out other gene-targeting experiments, including replacing the mouse gene for ApoE with common variants of the human gene. [14] As of 2017, her research continues to focus on atherosclerosis, and encompasses molecular pathology as well as genetics. [1] She also researches other multifactorial diseases, including diabetes and high blood pressure. [2] [4]
Maeda was married to the British-born geneticist Oliver Smithies (1925–2017). [16]
Apolipoproteins are proteins that bind lipids to form lipoproteins. They transport lipids in blood, cerebrospinal fluid and lymph.
The low-density lipoprotein receptor (LDL-R) is a mosaic protein of 839 amino acids that mediates the endocytosis of cholesterol-rich low-density lipoprotein (LDL). It is a cell-surface receptor that recognizes apolipoprotein B100 (ApoB100), which is embedded in the outer phospholipid layer of very low-density lipoprotein (VLDL), their remnants—i.e. intermediate-density lipoprotein (IDL), and LDL particles. The receptor also recognizes apolipoprotein E (ApoE) which is found in chylomicron remnants and IDL. In humans, the LDL receptor protein is encoded by the LDLR gene on chromosome 19. It belongs to the low density lipoprotein receptor gene family. It is most significantly expressed in bronchial epithelial cells and adrenal gland and cortex tissue.
Oliver Smithies was a British-American geneticist and physical biochemist. He is known for introducing starch as a medium for gel electrophoresis in 1955, and for the discovery, simultaneously with Mario Capecchi and Martin Evans, of the technique of homologous recombination of transgenic DNA with genomic DNA, a much more reliable method of altering animal genomes than previously used, and the technique behind gene targeting and knockout mice. He received the Nobel Prize in Physiology or Medicine in 2007 for his genetics work.
Apolipoprotein E (Apo-E) is a protein involved in the metabolism of fats in the body of mammals. A subtype is implicated in the Alzheimer's disease and cardiovascular diseases. It is encoded in humans by the gene APOE.
Apolipoprotein B (ApoB) is a protein that in humans is encoded by the APOB gene. It is commonly used to detect risk of atherosclerotic cardiovascular disease.
Apolipoprotein C-II, or apolipoprotein C2 is a protein that in humans is encoded by the APOC2 gene.
Familial hypercholesterolemia (FH) is a genetic disorder characterized by high cholesterol levels, specifically very high levels of low-density lipoprotein cholesterol, in the blood and early cardiovascular diseases. The most common mutations diminish the number of functional LDL receptors in the liver or produce abnormal LDL receptors that never go to the cell surface to function properly. Since the underlying body biochemistry is slightly different in individuals with FH, their high cholesterol levels are less responsive to the kinds of cholesterol control methods which are usually more effective in people without FH. Nevertheless, treatment is usually effective.
Molecular cellular cognition (MCC) is a branch of neuroscience that involves the study of cognitive processes with approaches that integrate molecular, cellular and behavioral mechanisms. Key goals of MCC studies include the derivation of molecular and cellular explanations of cognitive processes, as well as finding mechanisms and treatments for cognitive disorders.
Apolipoprotein AI(Apo-AI) is a protein that in humans is encoded by the APOA1 gene. As the major component of HDL particles, it has a specific role in lipid metabolism.
Apolipoprotein C-III also known as apo-CIII, and apolipoprotein C3, is a protein that in humans is encoded by the APOC3 gene. Apo-CIII is secreted by the liver as well as the small intestine, and is found on triglyceride-rich lipoproteins such as chylomicrons, very low density lipoprotein (VLDL), and remnant cholesterol.
Apolipoprotein D(ApoD) is a protein that in humans is encoded by the APOD gene. Unlike other lipoproteins, which are mainly produced in the liver, apolipoprotein D is mainly produced in the brain and testes. It is a 29 kDa glycoprotein discovered in 1963 as a component of the high-density lipoprotein (HDL) fraction of human plasma. It is the major component of human mammary cyst fluid. The human gene encoding it was cloned in 1986 and the deduced protein sequence revealed that ApoD is a member of the lipocalin family, small hydrophobic molecule transporters. ApoD is 169 amino acids long, including a secretion peptide signal of 20 amino acids. It contains two glycosylation sites (aspargines 45 and 78) and the molecular weight of the mature protein varies from 20 to 32 kDa (see figure 1).
Apolipoprotein A-V is a protein that in humans is encoded by the APOA5 gene on chromosome 11. It is significantly expressed in liver. The protein encoded by this gene is an apolipoprotein and an important determinant of plasma triglyceride levels, a major risk factor for coronary artery disease. It is a component of several lipoprotein fractions including VLDL, HDL, chylomicrons. It is believed that apoA-V affects lipoprotein metabolism by interacting with LDL-R gene family receptors. Considering its association with lipoprotein levels, APOA5 is implicated in metabolic syndrome. The APOA5 gene also contains one of 27 SNPs associated with increased risk of coronary artery disease.
Apolipoprotein A-II is a protein that in humans is encoded by the APOA2 gene. It is the second most abundant protein of the high density lipoprotein particles. The protein is found in plasma as a monomer, homodimer, or heterodimer with apolipoprotein D. ApoA-II regulates many steps in HDL metabolism, and its role in coronary heart disease is unclear. Remarkably, defects in this gene may result in apolipoprotein A-II deficiency or hypercholesterolemia.
Apolipoprotein A-IV is plasma protein that is the product of the human gene APOA4.
Proprotein convertase subtilisin/kexin type 9 (PCSK9) is an enzyme encoded by the PCSK9 gene in humans on chromosome 1. It is the 9th member of the proprotein convertase family of proteins that activate other proteins. Similar genes (orthologs) are found across many species. As with many proteins, PCSK9 is inactive when first synthesized, because a section of peptide chains blocks their activity; proprotein convertases remove that section to activate the enzyme. The PCSK9 gene also contains one of 27 loci associated with increased risk of coronary artery disease.
Microsomal triglyceride transfer protein large subunit is a protein that in humans is encoded by the MTTP gene.
Phosphatidylinositol-glycan-specific phospholipase D is an enzyme that in humans is encoded by the GPLD1 gene.
ATP-binding cassette sub-family A member 7 is a protein that in humans is encoded by the ABCA7 gene.
Jan Leslie Breslow is an American physician and medical researcher who studies atherosclerosis. As of 2017, he is Frederick Henry Leonhardt Professor at Rockefeller University and directs the university's Laboratory of Biochemical Genetics and Metabolism.
Barbara Hyde Bowman was an American biologist, geneticist, and educator who was known for her research in human blood proteins. Her work characterized variants of globins, the family of proteins responsible for transporting blood in oxygen, and in 1984, Oliver Smithies and she showed that variations in haptoglobins were due to polymorphisms in the HP gene.
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