Recent advances in the treatment of pathogenic infections using antibiotics and nano-drug delivery vehicles

Vo Van Giau, Seong Soo A An, John Hulme Department of Bionano Technology, Gachon Bionano Research Institute, Gachon University, Seongnam-si, Gyeonggi-do, South Korea Abstract: The worldwide misuse of antibiotics and the subsequent rise of multidrug-resistant pathogenic bacteria have prompted a paradigm shift in the established view of antibiotic and bacterial–human relations. The clinical failures of conventional antibiotic therapies are associated with lengthy detection methods, poor penetration at infection sites, disruption of indigenous microflora and high potential for mutational resistance. One of the most promising strategies to improve the efficacy of antibiotics is to complex them with micro or nano delivery materials. Such materials/vehicles can shield antibiotics from enzyme deactivation, increasing the therapeutic effectiveness of the drug. Alternatively, drug-free nanomaterials that do not kill the pathogen but target virulent factors such as adhesins, toxins, or secretory systems can be used to minimize resistance and infection severity. The main objective of this review is to examine the potential of the aforementioned materials in the detection and treatment of antibiotic-resistant pathogenic organisms. Keywords: antibiotics, resistance, polymer, chitosan, gold, recombinant, targeted, pathoge

Role of apolipoprotein E in neurodegenerative diseases

Vo Van Giau,1 Eva Bagyinszky,1 Seong Soo A An,1 SangYun Kim2 1Department of Bionano Technology, Gachon Medical Research Institute, Gachon University, Seongnam, South Korea; 2Department of Neurology, Seoul National University College of Medicine in Seoul National Bundang Hospital, Seoul, South Korea Abstract: Apolipoprotein E (APOE) is a lipid-transport protein abundantly expressed in most neurons in the central nervous system. APOE-dependent alterations of the endocytic pathway can affect different functions. APOE binds to cell-surface receptors to deliver lipids and to the hydrophobic amyloid-β peptide, regulating amyloid-β aggregations and clearances in the brain. Several APOE isoforms with major structural differences were discovered and shown to influence the brain lipid transport, glucose metabolism, neuronal signaling, neuroinflammation, and mitochondrial function. This review will summarize the updated research progress on APOE functions and its role in Alzheimer’s disease, Parkinson’s disease, cardiovascular diseases, multiple sclerosis, type 2 diabetes mellitus, Type III hyperlipoproteinemia, vascular dementia, and ischemic stroke. Understanding the mutations in APOE, their structural properties, and their isoforms is important to determine its role in various diseases and to advance the development of therapeutic strategies. Targeting APOE may be a potential approach for diagnosis, risk assessment, prevention, and treatment of various neurodegenerative and cardiovascular diseases in humans. Keywords: apolipoprotein E, pathogenesis, disease

A pathogenic PSEN2 p.His169Asn mutation associated with early-onset Alzheimer’s disease

Vo Van Giau,1,* Jung-Min Pyun,2,* Eva Bagyinszky,2 Seong Soo A An,1 SangYun Kim2 1Department of BioNano Technology, Gachon Medical Research Institute, Gachon University, Seongnam, South Korea; 2Department of Neurology, Seoul National University College of Medicine & Neurocognitive Behavior Center, Seoul National University Bundang Hospital, Seongnam, South Korea *These authors contributed equally to this work Background: Autosomal dominant early-onset Alzheimer’s disease (EOAD) is genetically heterogeneous and has been associated with mutations in 3 different genes, coding for amyloid precursor protein (APP), presenilin 1 (PSEN1), and presenilin 2 (PSEN2). Most frequent cases are associated with mutations in the PSEN1 gene, whereas mutations in the APP and PSEN2 genes are rare. Methods: Patient who presented progressive memory decline in her 50s was enrolled in this study. A broad battery of neuropsychological tests and neuroimaging was applied to make the diagnosis. Genetic tests were performed in the patient to evaluate possible mutations using next-generation sequencing (NGS). The pathogenic nature of missense mutation and its 3D protein structure prediction were performed by in silico prediction programs. Results: A pathogenic mutation in the PSEN2 gene in a Korean patient associated with EOAD was identified. Targeted Next-generation sequencing and Sanger sequencing revealed a heterozygous C to A transition at position 505 (c.505C>A), resulting in a probably missense mutation at codon 169 (p.His169Asn) in PSEN2. PolyPhen-2 and SIFT software analyses predicted this mutation to be a probable damaging variant. This hypothesis was supported by the results of 3D in silico modelling analyses that predicted the p.His169Asn may result in major helix torsion due to histidine to asparagine substitution. Mutation may cause additional stresses with hydrophobic residues on the surface that interact inside the transmembrane domain III, which is a conserved domain in PSEN2 His169. Conclusion: These findings revealed that the p.His169Asn might be an important residue in PSEN2, which may alter the functions of PSEN2, suggesting its potential involvement with AD phenotype. Future functional studies are needed to evaluate the role of PSEN2 p.His169Asn mutation in AD disease progression. Keywords: Alzheimer’s disease, p.His169Asn mutation, presenilin-2, next-generation sequencin

Characterization of mutations in PRNP (prion) gene and their possible roles in neurodegenerative diseases

Eva Bagyinszky,1 Vo Van Giau,1 Young Chul Youn,2 Seong Soo A An,1 SangYun Kim3 1Department of Bionano Technology, Gachon Bionano Research Institute, Gachon University, Gyeonggi-do, South Korea; 2Department of Neurology, Chung-Ang University College of Medicine, Seoul, South Korea; 3Department of Neurology, Seoul National University College of Medicine & Neurocognitive Behavior Center, Seoul National University Bundang Hospital, Seongnam, South Korea Abstract: Abnormal prion proteins are responsible for several fatal neurodegenerative diseases in humans and in animals, including Creutzfeldt–Jakob disease (CJD), Gerstmann–Sträussler–Scheinker disease, and fatal familial insomnia. Genetics is important in prion diseases, but in the most cases, cause of diseases remained unknown. Several mutations were found to be causative for prion disorders, and the effect of mutations may be heterogeneous. In addition, different prion mutations were suggested to play a possible role in additional phenotypes, such as Alzheimer’s type pathology, spongiform encephalopathy, or frontotemporal dementia. Pathogenic nature of several prion mutations remained unclear, such as M129V and E219K. These two polymorphic sites were suggested as either risk factors for different disorders, such as Alzheimer’s disease (AD), variant CJD, or protease-sensitive prionopathy, and they can also be disease-modifying factors. Pathological overlap may also be possible with AD or progressive dementia, and several patients with prion mutations were initially diagnosed with AD. This review also introduces briefly the diagnosis of prion diseases and the issues with their diagnosis. Since prion diseases have quite heterogeneous phenotypes, a complex analysis, a combination of genetic screening, cerebrospinal fluid biomarker analysis and imaging technologies could improve the early disease diagnosis. Keywords: genetics, mutation, prion, PRNP gene, Creutzfeldt–Jakob disease, Gerstmann–Sträussler–Scheinker disease, fatal familial insomnia, Alzheimer’s disease, diagnosi

Genome-editing applications of CRISPR–Cas9 to promote in vitro studies of Alzheimer’s disease

Vo Van Giau,1,* Hyon Lee,2,* Kyu Hwan Shim,1 Eva Bagyinszky,1 Seong Soo A An1 1Department of Bionano Technology, Gachon University, Seongnam, South Korea; 2Department of Neurology, Gachon University Gil Medical Center, Incheon, South Korea *These authors contributed equally to this work Abstract: Genetic variations play an important role in the clinical presentation and progression of Alzheimer’s disease (AD), especially early-onset Alzheimer’s disease. Hundreds of mutations have been reported with the majority resulting from alterations in β-amyloid precursor protein (APP), presenilin 1 (PSEN1), or presenilin 2 (PSEN2) genes. The roles of these mutations in the pathogenesis of AD have been classically confirmed or refuted through functional studies, where the mutations are cloned, inserted into cell lines, and monitored for changes in various properties including cell survival, amyloid production, or Aβ42/40 ratio. However, these verification studies tend to be expensive, time consuming, and inconsistent. Recently, the clustered regularly interspaced short palindromic repeats-CRISPR-associated protein 9 (CRISPR–Cas9) system was developed, which improves sequence-specific gene editing in cell lines, organs, and animals. CRISPR–Cas9 is a promising tool for the generation of models of human genetic diseases and could facilitate the establishment of new animal AD models and the observation of dynamic bioprocesses in AD. Here, we recapitulated the history of CRISPR technology, recent progress, and, especially, its potential applications in AD-related genetic, animal modeling, and functional studies. Keywords: Alzheimer’s disease, CRISPR–Cas9, mutation, Aβ42/40 rati

Identification of a novel mutation in APP gene in a Thai subject with early-onset Alzheimer's disease

Vo Van Giau,1,* Vorapun Senanarong,2,* Eva Bagyinszky,1 Chanin Limwongse,2 Seong Soo A An,1 SangYun Kim3 1Department of Bionano Technology, Gachon Bionano Research Institute, Gachon University, Seongnam, South Korea; 2Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand; 3Department of Neurology, Seoul National University College of Medicine & Neurocognitive Behavior Center, Seoul National University Bundang Hospital, Seongnam, South Korea *These authors contributed equally to this work Introduction: Early-onset Alzheimer’s disease (AD) accounts for than less 1% of all AD cases, with large variation in the reported genetic contributions of known dementia genes. Mutations in the amyloid precursor protein (APP) gene were the first to be recognized as the cause of AD. Methods: Here, a male patient with probable early-onset AD at the age of 55 years from Thailand was investigated by next-generation sequencing. Results: A novel mutation in exon 14 of APP (c.1810C>T, p.V604M) was found. He initially illustrated the clinical manifestations of progressive nonfluent aphasia in 2011. However, he was finally diagnosed with AD presenting logopenic aphasia in 2013. The follow-up magnetic resonance imaging scan showed progression of hippocampal trophy compared with the initial image. A 3D protein structure model revealed that V604M exchange could result in significant changes in the APP protein due to the increased hydrophobicity of methionine in the helix, which could result in altering of the APP functions. Conclusion: Additional studies to characterize APP p.V604M are necessary to further understand the effects of this mutation. Keywords: APP, Alzheimer’s disease, Thailand, V604

Apolipoprotein ε7 allele in memory complaints: insights through protein structure prediction

Young Chul Youn,1,* Yong Kwan Lim,2,* Su-Hyun Han,1 Vo Van Giau,3 Mi-Kyung Lee,2 Kwang-Yeol Park,1 SangYun Kim,4,5 Eva Bagyinszky,3 Seong Soo A An,3 Hye Ryoun Kim2 1Department of Neurology, 2Department of Laboratory Medicine, Chung-Ang University College of Medicine, Seoul, 3College of BioNano Technology, Gachon BioNano Research Institute, Gachon University, 4Department of Neurology, Seoul National University Bundang Hospital, 5Department of Neurology, Seoul National University College of Medicine, Seongnam, South Korea *These authors contributed equally to this work Purpose: APOE ε7 gene is a rare mutant form of APOE ε3. The mutation occurs in the lipid-binding domain of APOE. Based on the protein’s structure, APOE ε7 is expected to function in lipid and β-amyloid metabolism, similar to APOE ε4. However, unlike that for APOE ε4, the mechanisms responsible for Alzheimer’s disease (AD) cases associated with APOE ε7 expression have not been elucidated. The present study aims to investigate the association between APOE ε7 expression and cognitive impairment. Methods: APOE was sequenced in DNA samples collected from 344 memory-complaint patients who visited the memory clinic, and from 345 non-memory-complaint individuals from the health promotion center. The protein structures of ApoE3, ApoE4, and ApoE7 were predicted. Results: Three ε3/ε7 heterozygote individuals who were all classified under the memory-complaint group were identified. Of these, two subjects were clinically diagnosed with AD with small vessel disease, and the remaining individual was diagnosed with subjective cognitive impairment. This study predicted the protein structures of ApoE3, ApoE4, and ApoE7 and determined the three-dimensional structure of the carboxy terminus of ApoE7, which participates in an electrostatic domain interaction similar to that of APOE ε4. APOE K244 or K245 mutations for APOE ε7 were not found in the Korean reference genome database, which contains information (http://152.99.75.168/KRGDB/browser/mainBrowser.jsp) from 622 healthy individuals. Conclusion: As verified by the results of structural prediction, APOE ε7 could serve as another risk factor for cognitive impairment and is particularly associated with vascular disease. However, additional studies are required to validate the pathogenic nature of APOE ε7. Keywords: apolipoprotein structure, Alzheimer’s disease, vascular cognitive impairment, small vessel diseas