Laura Manuelidis is a physician and neuropathologist at Yale University.
Manuelidis earned her B.A. degree from Sarah Lawrence College, where she studied poetry, and her M.D. is from Yale Medical School. She is head of the section of Neuropathology in the department of Surgery at Yale [1] and is also a member of the Neuroscience and Virology faculty. She has been active on numerous government committees including the Advisory Panel on Alzheimer's disease and US FDA advisory panel, has been a member of editorial boards, and chair of international meetings. She has also published 3 books of poetry.
Manuelidis has made major contributions in two areas: A) the discovery of large chromosomal DNA repeats and the elucidation of their role in the organization and structure of chromosomes in metaphase and interphase nuclei; B) the experimental investigation of the infectious agents that cause human Transmissible Encephalopathy (TSE) diseases including Creutzfeldt–Jakob disease (CJD), kuru and BSE ("mad cow disease"). Transmission to small animals and cells in culture exposed basic biologic and molecular agent facts most consistent with an exponentially replicating ~25 nm viral particle that contains an essential but unknown nucleic acid for infection.[ citation needed ] This contrasts with the assertion that the host encoded amyloid forming prion protein, without nucleic acid, is the infectious agent.
Early in her career, Manuelidis discovered major unknown DNA sequence motifs, and demonstrated their megabase organization in metaphase chromosomes and interphase nuclei. Using restriction enzymes on whole human DNA and extracting specific gel bands, an approach no one had used previously for whole mammalian genomes, she discovered human complex repeated (α satellite) DNA sequences and localized them in centromeres. [2] [3] They were homologous to simian, but not simpler mouse centromere repeats. [4] These late replicating sequences, that contain few if any genes, define all human chromosome centromeres as shown by the development of high resolution in-situ hybridization. [5] As in other mammalian cells, centromeres are critical for proper segregation of chromosomes between two new daughter cells during mitosis, and the discovery and localization of these satellite sequences have facilitated diagnosis of trisomy and chromosomal aberrations in genetic diseases and tumors. Manuelidis also discovered, isolated, and sequenced the human long interspersed L1 repeats (LINES) and showed they contained a transcriptional open reading frame. [6] She found these abundant L1 repeats concentrated in Giemsa dark bands on chromosome arms that contain many tissue-specific genes [7] whereas ALU short repeats concentrate in light bands with the majority of housekeeping genes. L1 repeats are conserved in evolution and show 70% homology to mouse L1 repeats. After retroviral HIV was sequenced, others deduced that L1 repeats were retroviral. It thus became clear that these ancient large retroviral invaders entered the genome and were symbiotically transfigured, or pathologically tamed, during evolution to attain a structural, and possibly functional role in megabase chromosome band domains.The enormous sizes of L1 and Alu rich domains were also demonstrated by pulse-field electrophoresis. [8] Additional endogenous retroviral DNAs, such as those that produce retroviral intracisternal A particles (IAP) in rodents, as well as less numerous human endogenous retroviral repeats, are also integrated in specific chromosome locations. [9] This further undermines the assumption repeated DNAs are parasitic "junk".
Manuelidis also opened up the field of 3-dimensional chromosome structure in the interphase nucleus of differentiated cells by combining optical serial sections and high resolution in-situ hybridization of specific DNA sequences. These studies dramatically transfigured the picture of interphase nuclei. Previously, interphase compartments were viewed as ill-defined dense heterochromatic blobs beside unorganized euchromatic chromatin spaghetti with no cohesive 3-D structure. In differentiated neurons very distinct patterns of individual centromere positions were demonstrated for each neuronal subtype. These positions are conserved in evolution even though centromeric DNA repeats are species-specific. [10] By charting the movement of the X chromosome in large neurons in epilepsy, [11] and the movement of centromeres during post-mitotic neuronal development, [12] dynamic changes of large chromosome were illuminated. High-resolution mapping of whole individual human chromosomes in mouse and hamster-hybrid human cells further showed each chromosome was compact and occupied its own individual space or "territory". [13] [14]
An architectural model of chromosomes as they transit from metaphase to interphase fits the known DNA compaction in diploid cells and allows for rapid transitions and segregation during mitosis, as well as local extensions that accommodate transcription. [15] Mapping of whole individual chromosomes using high resolution DNA hybridization of chromosome specific libraries developed here [16] [17] subsequently were useful for resolving chromosome changes in complex genetic diseases and tumor progression. Finally, the insertion of a huge 11 megabase transgene of the globin exon (lacking introns) was recognized by cells, and silenced by compaction together with transcriptionally inert heterochromatic centromeres in neurons. [18] This demonstrates that uninterrupted repeats are capable of inducing specific functional and structural changes during interphase. It is likely that this feature operates sequentially during cell differentiation.
The lab of EE Manuelidis and L Manuelidis was the first to serially transmit human Creutzfeldt–Jakob disease (CJD) to guinea pigs and small rodents. [19] [20] [21] This made it possible to demonstrate fundamental mechanisms of infection, including TSE agent uptake and spread via myeloid cells of the blood, [22] [23] a common route for most viruses. A lack of maternal transmission of sporadic CJD (sCJD) in long lived guinea pigs, [24] contrasts with the proposed germline inheritance of sCJD. As with viruses, different species vary in their susceptibility to specific TSE agent strains. Major agent strain distinctions from scrapie are encoded by different human TSE agents, such as sCJD, kuru of New Guinea, [25] bovine-linked vCJD, [26] and Asiatic CJD. These were discovered and documented though experimental transmissions to normal mice, hamsters and monotypic cell cultures at Yale. Prion protein bands fail to distinguish very different TSE strains in standard mouse brains.
Manuelidis and colleagues were the first to show that prion protein amyloid was derived from a glycosylated 34kd precursor protein using lectins. PrP antibodies and selected lectins bound to the same protein in both normal and CJD and scrapie infected brain fractions. [27] Additionally, the correct sugar sequence of PrP was first demonstrated in the Manuelidis lab by sequential deglycosylation and unmasking of sugar residues. [28] Manuelidis and colleagues also developed monotypic cell cultures infected by many different human and sheep scrapie TSE strains, and developed rapid quantitative assays of infectious titers of 1 million fold or more for each strain. [29] As in the brain, misfolded PrP amounts show less than a 5 fold increase and could not even distinguish greater than 100 fold differences in infectivity of cultured agent strains. These culture studies further showed that PrP band patterns are cell-type dependent. Only rare strains show a PrP folding pattern that is distinctive in either brain or in monotypic cells, and a change in PrP bands does not induce any change in strain characteristics. [30] Moreover, TSE strains modify each other's replication in a virus-like fashion. Experiments in mice, and GT hypothalamic neuronal cells in culture, show both inhibitory and additive infectivity by two different TSE strains: one TSE strain can inhibit replication of a second more virulent strain [31] whereas two different strains can both simultaneously infect cells. [32]
Finally, dramatic changes in agent doubling time (weeks to a day) were documented for many TSE strains. TSE agents replicate every 24 hrs in culture, in marked contrast to their very slow and strain specific replication in the brain. This rapid agent replication in culture is likely due to release of agent constraints from the many complex host immune system in animals. [29] These include early microglial responses. [33] [34] [35] PrP amyloid itself can also behave as a defensive innate immune response to TSE agent infection, and high levels of PrP amyloid can abolish 99.999% of infectivity. [36] [37]
Manueldis has challenged the dominant assertion that host prion protein (PrP), without any nucleic acid, is the causal infectious agent in TSEs. The prion hypothesis was put forth by Stanley B. Prusiner, who won the 1997 Nobel Prize in Physiology or Medicine. [38] In contrast to the amyloid or "infectious form of host PrP", Manuelidis and colleagues showed that infectious CJD 25nm brain particles had a homogeneous viral density and size and separated from most prion protein. Disruption of CJD nucleic acid-protein complexes destroys infectivity. [39] Comparable 25 nm particles were also identified within CJD and scrapie infected cell cultures, but not in uninfected controls. As with isolated 25 nm brain particles, cultured cells particles did not bind PrP antibodies. [40]
Manuelidis stated that "Although much work remains to be done, there is a reasonable possibility these are the long sought viral particles that cause transmissible spongiform encephalopathies". She claims that misfolded prion protein probably is not infectious, and that there is no independent confirmation that recombinant PrP can be converted to an infectious form. However, the Prusiner group has published evidence of precisely the kind of conversion that Manueldis claims there is no evidence for. [41] As originally proposed, misfolded PrP amyloid might be an infectious structure or a pathological response protein. [42] Later evidence favored the pathological concept, with infectious viral particles binding to and converting receptor PrP to an amyloid form. [43] Much additional evidence points to an exogenous source of infectious TSE agents, and the claim that recombinant PrP can be made infectious has not been reproducible. [44] [45] [46] In fact, one can remove all detectable forms of PrP from infectious brain particles, yet these particles retain high infectivity. [47] Thus, PrP may not be an integral or required component of the infectious particle. [48] On the other hand, all high infectivity scrapie and CJD fractions contain nucleic acids when analyzed using modern amplification strategies. [49] When these nucleic acids are destroyed with nucleases that have no effect on PrP, 99.8% of the infectious titer is abolished. [50] Novel circular SPHINX DNAs from the microbiome of 1.8kb and 2.4kb have been identified in isolated infectious particles, but their role in infection and/or disease is not yet clear because they are also present at much lower levels in non-infectious preparations. Only a few infectious particle nucleic acid sequences have been analyzed to date. Nevertheless, host innate immune responses, including a remarkably strong interferon response to infection, [51] further demonstrate TSE agents are recognized as foreign infectious invaders. Misfolded PrP does not elicit this effect.
Creutzfeldt–Jakob disease (CJD), also known as subacute spongiform encephalopathy or neurocognitive disorder due to prion disease, is a fatal neurodegenerative disease. Early symptoms include memory problems, behavioral changes, poor coordination, and visual disturbances. Later symptoms include dementia, involuntary movements, blindness, weakness, and coma. About 70% of people die within a year of diagnosis. The name "Creutzfeldt–Jakob disease" was introduced by Walther Spielmeyer in 1922, after the German neurologists Hans Gerhard Creutzfeldt and Alfons Maria Jakob.
A prion is a misfolded protein that induces misfolding in normal variants of the same protein, leading to cellular death. Prions are responsible for prion diseases, known as transmissible spongiform encephalopathies (TSEs), which are fatal and transmissible neurodegenerative diseases affecting both humans and animals. These proteins can misfold sporadically, due to genetic mutations, or by exposure to an already misfolded protein, leading to an abnormal three-dimensional structure that can propagate misfolding in other proteins.
Stanley Ben Prusiner is an American neurologist and biochemist. He is the director of the Institute for Neurodegenerative Diseases at University of California, San Francisco (UCSF). Prusiner discovered prions, a class of infectious self-reproducing pathogens primarily or solely composed of protein, a scientific theory considered by many as a heretical idea when first proposed. He received the Albert Lasker Award for Basic Medical Research in 1994 and the Nobel Prize in Physiology or Medicine in 1997 for research on prion diseases developed by him and his team of experts beginning in the early 1970s.
Scrapie is a fatal, degenerative disease affecting the nervous systems of sheep and goats. It is one of several transmissible spongiform encephalopathies (TSEs), and as such it is thought to be caused by a prion. Scrapie has been known since at least 1732 and does not appear to be transmissible to humans. However, it has been found to be experimentally transmissible to humanised transgenic mice and non-human primates.
Transmissible spongiform encephalopathies (TSEs), also known as prion diseases, are a group of progressive, incurable, and fatal conditions that are associated with prions and affect the brain and nervous system of many animals, including humans, cattle, and sheep. According to the most widespread hypothesis, they are transmitted by prions, though some other data suggest an involvement of a Spiroplasma infection. Mental and physical abilities deteriorate and many tiny holes appear in the cortex causing it to appear like a sponge when brain tissue obtained at autopsy is examined under a microscope. The disorders cause impairment of brain function which may result in memory loss, personality changes, and abnormal or impaired movement which worsen over time.
The virino is a hypothetical infectious particle once theorized to be the cause of scrapie and other degenerative diseases of the central nervous system. It was thought to consist of nucleic acids within a protective coat of host cell proteins. The hypothesis was never widely accepted, and the causative agents responsible for these diseases are now widely accepted to be prions.
Spiroplasma is a genus of Mollicutes, a group of small bacteria without cell walls. Spiroplasma shares the simple metabolism, parasitic lifestyle, fried-egg colony morphology and small genome of other Mollicutes, but has a distinctive helical morphology, unlike Mycoplasma. It has a spiral shape and moves in a corkscrew motion. Many Spiroplasma are found either in the gut or haemolymph of insects where they can act to manipulate host reproduction, or defend the host as endosymbionts. Spiroplasma are also disease-causing agents in the phloem of plants. Spiroplasmas are fastidious organisms, which require a rich culture medium. Typically they grow well at 30 °C, but not at 37 °C. A few species, notably Spiroplasma mirum, grow well at 37 °C, and cause cataracts and neurological damage in suckling mice. The best studied species of spiroplasmas are Spiroplasma poulsonii, a reproductive manipulator and defensive insect symbiont, Spiroplasma citri, the causative agent of citrus stubborn disease, and Spiroplasma kunkelii, the causative agent of corn stunt disease.
Feline spongiform encephalopathy (FSE) is a neurodegenerative disease that affects the brains of felines. This disease is known to affect domestic, captive, and wild species of the family Felidae. Like BSE, this disease can take several years to develop. It is currently believed that this condition is a result of felines ingesting bovine meat contaminated with BSE.
Protein misfolding cyclic amplification (PMCA) is an amplification technique to multiply misfolded prions originally developed by Soto and colleagues. It is a test for spongiform encephalopathies like chronic wasting disease (CWD) or bovine spongiform encephalopathy (BSE).
The major prion protein (PrP) is encoded in the human body by the PRNP gene also known as CD230. Expression of the protein is most predominant in the nervous system but occurs in many other tissues throughout the body.
Variant Creutzfeldt–Jakob disease (vCJD), formerly known as New variant Creutzfeldt–Jakob disease (nvCJD) and referred to colloquially as "mad cow disease" or "human mad cow disease" to distinguish it from its BSE counterpart, is a fatal type of brain disease within the transmissible spongiform encephalopathy family. Initial symptoms include psychiatric problems, behavioral changes, and painful sensations. In the later stages of the illness, patients may exhibit poor coordination, dementia and involuntary movements. The length of time between exposure and the development of symptoms is unclear, but is believed to be years to decades. Average life expectancy following the onset of symptoms is 13 months.
Kuru is a rare, incurable, and fatal neurodegenerative disorder that was formerly common among the Fore people of Papua New Guinea. Kuru is a form of prion disease which leads to tremors and loss of coordination from neurodegeneration.
Prion protein 2 (dublet), also known as PRND, or Doppel protein, is a protein which in humans is encoded by the PRND gene.
Bovine spongiform encephalopathy (BSE), commonly known as mad cow disease, is an incurable and invariably fatal neurodegenerative disease of cattle. Symptoms include abnormal behavior, trouble walking, and weight loss. Later in the course of the disease, the cow becomes unable to function normally. There is conflicting information about the time between infection and onset of symptoms. In 2002, the World Health Organization suggested it to be approximately four to five years. Time from onset of symptoms to death is generally weeks to months. Spread to humans is believed to result in variant Creutzfeldt–Jakob disease (vCJD). As of 2018, a total of 231 cases of vCJD had been reported globally.
The brain, like most other internal organs, or offal, can serve as nourishment. Brains used for nourishment include those of pigs, squirrels, rabbits, horses, cattle, monkeys, chickens, camels, fish, lamb, and goats. In many cultures, different types of brain are considered a delicacy.
Surround optical-fiber immunoassay (SOFIA) is an ultrasensitive, in vitro diagnostic platform incorporating a surround optical-fiber assembly that captures fluorescence emissions from an entire sample. The technology's defining characteristics are its extremely high limit of detection, sensitivity, and dynamic range. SOFIA's sensitivity is measured at the attogram level (10−18 g), making it about one billion times more sensitive than conventional diagnostic techniques. Based on its enhanced dynamic range, SOFIA is able to discriminate levels of analyte in a sample over 10 orders of magnitude, facilitating accurate titering.
In biology, a pathogen, in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ.
Frank O. Bastian is an American physician and neuropathologist, who previously worked at Louisiana State University, moved to a university in New Orleans in 2019. He specializes in the transmissible spongiform encephalopathies (TSEs), which include, but are not limited to, Bovine spongiform encephalopathy (BSE) "Mad cow disease" in cattle, scrapie in sheep and goats, and Creutzfeldt–Jakob disease (CJD) in humans.
Real-time quaking-induced conversion (RT-QuIC) is a highly sensitive assay for prion detection.
Michael Coulthart is a Canadian microbiologist who is employed as the head of the Canadian Creutzfeldt–Jakob Disease Surveillance System (CJDSS) within the Public Health Agency of Canada (PHAC), which terms CJD a zoonotic and infectious disease. In 2006, a working group named "classic CJD" as well as Variant Creutzfeldt–Jakob disease as two notifiable diseases. It is unknown whether PHAC tracks in an official capacity other transmissible spongiform encephalopathies (TSE), but Coulthart is on the Advisory Committee of the Center for Infectious Disease Research and Policy for Chronic Wasting Disease of cervidae.
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