Structural Biochemistry/Eizabeth Neufeld

Elizabeth Neufeld

Elizabeth Neufeld was a geneticist whose work mainly focused on mucopolysaccharides. Her main accomplishments were accidentally finding corrections in biological defects that led to therapies for metabolic disorders and the possible connection of Sanfilippo syndrome and Alzheimer disease.

Early in Life

Elizabeth Neufeld was born in Paris but moved to New York in 1940. She attended Joan of Arc Junior High School and went on to Hunter High School. Her favorite class was Latin and in high school she was first introduced to biology. She attended Queens community college and took almost every science class that was available. Soon after, she received a position at Jackson Lab located in Bar Harbor Maine and was an assistant for Elizabeth (Tibby) Russel. Russel was a mouse geneticist and assigned Neufeld to study the variability of blood cells among mouse strains. She also took part in studies with mouse mutants at the W locus point with severely impaired Hematopoiesis.She began graduate school at the university of Rochester but left after a year due to the death of her father. After that she volunteered at the Institute of De Broglie Physico Chimique. She was hired a s a technician at the McCollum-Pratt Institute and worked on pyridine nucleotide transhydrogenase, an enzyme purified from pseudomonas and beef heart whose mechanism was unknow. She asked the Professor Kaplan to become his grad student but he refused and said "women were not happy in grad school." Kaplan did recommend her to his friend at UC Berkely, W.Z. Hassid.

UC Berkeley

Neufeld was enroled as a student at UC Berkeley and worked with starches and glycogen. she found a paradox in her research of a mechanism that catalyzed the transfer of glucose 1-phosphate to the outer branches of a primer amylopectin and glycogen. The product of the reaction was called amylose because it resembled the blue color of natural emylose when mixed with Iodine. The paradox of her reaction was that the product was shorter than what was expected but still gave off a blue color. The reason for this was the confusion of naming the product Amylose and natural Amylose. they were thought to be the same thing but were in fact different. From her research she awarded a PhD.

After Berkeley

After leaving Berkeley, Neufeld joined the lab of Daniel Mazias and his research on sea urchin eggs. Her task was to verify that the cycle of a fertilized egg was associated with changes in cellular concentration of non protein sulfhydryl groups.She in fact found no change and left this lab to join up with Victor Ginsburg. Together they discovered pyrophosphorylases and empirases that would catalyze the synthesis of UDP sugars in mung bean extracts. Soon after, Neufeld went to work with David Feingold and together they synthesized polymers important to place cell walls. They found when plants were injured they produced callose. They also worked with several other reactions like UDP decarboxylatin to UDP - xylose and UDP epimirization to UDP - galacturonic acid which were assumed to be precursors to complex cell wall polymers. This period in time was one of the happiest in her life.

Hurler and Hunter Syndrome

Both Hurler and Hunter syndrome are metabolic disorders in which the degradation of mucopolysaccharides in inhibited. Fribroblasts from Hurler cells were similar to those in Hunter cells. Cells with these disorders have an influx of mucopolysaccharides and were first believed that mucopolysaccharides were being over synthesized. When tested, radioactivity in Hurler and Hunter cells continued to increase linearly while normal cells leveled off after 4 hours. This proved previous theories of the syndromes being lysosomal disorders. But soon they accidentally discovered how to correct the disorders in cultured environments.When analyzing Hurler and Hunter cells, they were both accidentally mixed and were allowed to culture. When tested, the mixed culture showed the normalization of normal cells and did not increase linearly past four hours. The then created intentional mixtures of hunter-hurler, hunter-normal and hurler-normal and to their surprise they all showed normal cell patterns. This kicked off the idea that if corrections could be made in mucopolysaccharide metabolism in cultured environments, then therapies could be made to help patients with these diseases. The cells secreted corrective factors to one another. If the culture corrected itself then it was assumed that the cells were of different genotypes and if the cells did not then they were of the same genotypes. It also showed mucopolysaccharide accumulation in cells deficient in B-glucuronidase coulde be fixed by the addition of B-glucuronidase. This was later called Sly syndrome and helped support the corrective factors hypothesis that Hurler and Hunter Syndromes were lysosomal enzymes missing in deficient cells which were unknown during this discovery. It was soon found that Hurler patients were deficient in α-L-iduronidase activity and correction was accomplished by the uptake of phenyl - α-L-iduronidase. Although things looked bright, not all uptake was corrective. this suggested that there were specific structural elements on the enzyme that was required for uptake.

mannose-6-phosphate and treatments for α-L-Iduronidase Deficiency

Neufeld was analyzing β-hexosaminidase to search for the uptake structure but was beat to the finish line when another scientist discovered the uptake for β-glucuronidase structure to be mannose-6-phosphate. This modification was previously unknown in mammalian cells. A canine model was soon found and the opportunities for therapies looked bright. They used canine and human cDNA to produce recombinant DNA on Chinese ovarian hamster cells. The cells secreted a mannose-6-phosphate signal and was highly corrective in cultured fibroblasts. the enzyme proved useful in clearing glycoasminoglycn from many organs and had short and long term effects. Recombinant α-L-iduronidase enzyme was used to treat α-L-iduronidase deficiency disease and was soon approved by the FDA. The FDA also approved the mannose-6-phosphate corrective system for Hunter and Maroteaux-Lamy Syndromes. These therapies looked bright but there were a few problems. First of all not all tissue were equally correctable by the enzymes. Also, the central nervous system would not respond to the injected enzyme because blood-brain barrier prevented the enzyme from entering the brain. A solution to the blood-brain barrier problem was to use Hematopoietic stem cells. The stem cells helped maintain mental development in patients with severe Hurler Syndrome when performed early enough in life. The treatment was implemented using cells of moncyte/macrophage lineage because these cells could cross the blood-brain barrier. These cells believed to correct neurons by either secreting α-L-iduronidase or replacing deficient microglia with healthy microglia.

Neufeld and the Sanfilippo Syndrome

The Sanfilippo Syndrome was also a muccopolysaccharide storage disease that involved manifestations in the brain. There are four types of Sanfilippo Syndrome and Neufeld worked with type B because it enzyme, α-N-acetylglucosaminidase, was the easiest to analyze and purify.They used a mouse model and discovered something odd. They found a sixfold increase in mRNA lysozymes in the affected mouse than in the normal mouse. The lysozyme was related resembled the tau protein which needed to be phosphorylated. During phosphorylation, the lysozyme protein was hyperphosphorylated and showed similar characteristics to hyperphosphorylated tau found in patients with Alzheimer disease. When antibodies were used, the lysozyme was stained similar to the hyperphosphorylated tau protein. She accidentally found a link in Sanfilippo syndrom and Alzheimer disease and opened doors for potential therapies to both diseases. Spador (discuss • contribs) 03:17, 17 November 2011 (UTC)

Information taken from "From Serendipity to Therapy".