Meta-Analysis of APP Expression Modulated by SARS-CoV-2 Infection via the ACE2 Receptor

Exposure to urban particulate matter alters responses of olfactory mucosal cells to SARS-CoV-2 infection

Respiratory viruses have a significant impact on health, as highlighted by the COVID-19 pandemic. Exposure to air pollution can contribute to viral susceptibility and be associated with severe outcomes, as suggested by recent epidemiological studies. Furthermore, exposure to particulate matter (PM), an important constituent of air pollution, is linked to adverse effects on the brain, including cognitive decline and Alzheimer's disease (AD). The olfactory mucosa (OM), a tissue located at the rooftop of the nasal cavity, is directly exposed to inhaled air and in direct contact with the brain. Increasing evidence of OM dysfunction related to neuropathogenesis and viral infection demonstrates the importance of elucidating the interplay between viruses and air pollutants at the OM. This study examined the effects of subacute exposure to urban PM 0.2 and PM 10-2.5 on SARS-CoV-2 infection using primary human OM cells obtained from cognitively healthy individuals and individuals diagnosed with AD. OM cells were exposed to PM and subsequently infected with the SARS-CoV-2 virus in the presence of pollutants. SARS-CoV-2 entry receptors and replication, toxicological endpoints, cytokine release, oxidative stress markers, and amyloid beta levels were measured. Exposure to PM did not enhance the expression of viral entry receptors or cellular viral load in human OM cells. However, PM-exposed and SARS-CoV-2-infected cells showed alterations in cellular and immune responses when compared to cells infected only with the virus or pollutants. These changes are highly pronounced in AD OM cells. These results suggest that exposure of human OM cells to PM does not increase susceptibility to SARS-CoV-2 infection in vitro, but it can alter cellular immune responses to the virus, particularly in AD. Understanding the interplay of air pollutants and COVID-19 can provide important insight for the development of public health policies and interventions to reduce the negative influences of air pollution exposure.

Amyloid precursor protein facilitates SARS-CoV-2 virus entry into cells and enhances amyloid-β-associated pathology in APP/PS1 mouse model of Alzheimer's disease

Although there are indications of a trend towards less severe acute respiratory symptoms and a decline in overall lethality from the novel Coronavirus Disease 2019 (COVID-19) caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), more and more attention has been paid to the long COVID, including the increased risk of Alzheimer's disease (AD) in COVID-19 patients. In this study, we aim to investigate the involvement of N-terminal amyloid precursor protein (APP) in SARS-CoV-2-induced amyloid-β (Aβ) pathology. Utilizing both in vitro and in vivo methodologies, we first investigated the interaction between the spike protein of SARS-CoV-2 and N-terminal APP via LSPR and CoIP assays. The in vitro impacts of APP overexpression on virus infection were further evaluated in HEK293T/ACE2 cells, SH-SY5Y cells, and Vero cells. We also analyzed the pseudovirus infection in vivo in a mouse model overexpressing human wild-type APP. Finally, we evaluated the impact of APP on pseudovirus infection within human brain organoids and assessed the chronic effects of pseudovirus infection on Aβ levels. We reported here for the first time that APP, the precursor of the Aβ of AD, interacts with the Spike protein of SARS-CoV-2. Moreover, both in vivo and in vitro data further indicated that APP promotes the cellular entry of the virus, and exacerbates Aβ-associated pathology in the APP/PS1 mouse model of AD, which can be ameliorated by N-terminal APP blockage. Our findings provide experimental evidence to interpret APP-related mechanisms underlying AD-like neuropathology in COVID-19 patients and may pave the way to help inform risk management and therapeutic strategies against diseases accordingly.

[Cognitive Impairment as a Sequela of COVID-19: Pathophysiology and Prospects for Treatment]

Cognitive impairment has been reported as a potential sequela of COVID-19. Risk factors associated with this impairment include advanced age, severe infection, and prolonged duration of anosmia (loss of smell). Furthermore, COVID-19 has been reported as a risk factor for Alzheimer disease, and even mild infections have been associated with visuospatial cognitive impairments. While multiple pathophysiological mechanisms have been implicated in COVID-19-related cognitive impairment, persistent infection by the SARS-CoV-2 virus is of particular interest due to its potential implications for treatment. Persistent infection could lead to cognitive impairments through mechanisms such as neurotoxicity mediated by spike proteins, neuroinflammation induced by cytokines, and neuronal cell fusion (syncytia). In terms of treatment, the effectiveness of vaccination has been demonstrated in meta-analyses, and drugs like metformin and antiviral agents hold promise.

The viral hypothesis in Alzheimer's disease: SARS-CoV-2 on the cusp

Increasing evidence highlights that infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has long-term effects on cognitive function, which may cause neurodegenerative diseases like Alzheimer's disease (AD) in the future. We performed an analysis of a possible link between SARS-CoV-2 infection and AD risk and proposed several hypotheses for its possible mechanism, including systemic inflammation, neuroinflammation, vascular endothelial injury, direct viral infection, and abnormal amyloid precursor protein metabolism. The purpose of this review is to highlight the impact of infection with SASR-CoV-2 on the future risk of AD, to provide recommendations on medical strategies during the pandemic, and to propose strategies to address the risk of AD induced by SASR-CoV-2. We call for the establishment of a follow-up system for survivors to help researchers better understand the occurrence, natural history, and optimal management of SARS-CoV-2-related AD and prepare for the future.

Amyloidogenic proteins in the SARS-CoV and SARS-CoV-2 proteomes

The phenomenon of protein aggregation is associated with a wide range of human diseases. Our knowledge of the aggregation behaviour of viral proteins, however, is still rather limited. Here, we investigated this behaviour in the SARS-CoV and SARS-CoV-2 proteomes. An initial analysis using a panel of sequence-based predictors suggested the presence of multiple aggregation-prone regions (APRs) in these proteomes and revealed a strong aggregation propensity in some SARS-CoV-2 proteins. We then studied the in vitro aggregation of predicted aggregation-prone SARS-CoV and SARS-CoV-2 proteins and protein regions, including the signal sequence peptide and fusion peptides 1 and 2 of the spike protein, a peptide from the NSP6 protein, and the ORF10 and NSP11 proteins. Our results show that these peptides and proteins can form amyloid aggregates. We used circular dichroism spectroscopy to reveal the presence of β-sheet rich cores in aggregates and X-ray diffraction and Raman spectroscopy to confirm the formation of amyloid structures. Furthermore, we demonstrated that SARS-CoV-2 NSP11 aggregates are toxic to mammalian cell cultures. These results motivate further studies about the possible role of aggregation of SARS proteins in protein misfolding diseases and other human conditions.

Epigenetic insight into effects of prenatal alcohol exposure on stress axis development: Systematic review with meta-analytic approaches

We conducted a systematic review with meta-analytic elements using publicly available Gene Expression Omnibus (GEO) datasets to determine the role of epigenetic mechanisms in prenatal alcohol exposure (PAE)-induced hypothalamic-pituitary-adrenal (HPA) axis dysfunctions in offspring. Several studies have demonstrated that PAE has long-term consequences on HPA axis functions in offspring. Some studies determined that alcohol-induced epigenetic alterations during fetal development persist in adulthood. However, additional research is needed to understand the major epigenetic events leading to alcohol-induced teratogenesis of the HPA axis. Our network analysis of GEO datasets identified key pathways relevant to alcohol-mediated histone modifications, DNA methylation, and miRNA involvement associated with PAE-induced alterations of the HPA axis. Our analysis indicated that PAE perturbated the epigenetic machinery to activate corticotrophin-releasing hormone, while it suppressed opioid, glucocorticoid receptor, and circadian clock genes. These results help to further our understanding of the epigenetic basis of alcohol's effects on HPA axis development.

Multifactorial Causation of Alzheimer's Disease Due to COVID-19

There are several implications of the surge in the incidence of pandemics and epidemics in the last decades. COVID-19 being the most remarkable one, showed the vulnerability of patients with neurodegenerative diseases like Alzheimer's disease (AD). This review studies the pathological interlinks and triggering factors between the two illnesses and proposes a multifactorial pathway of AD causation due to COVID-19. The article evaluates and describes all the postulated hypotheses which explain the etiology and possible pathogenesis of the disease in four domains: Inflammation & Neurobiochemical interactions, Oxidative Stress, Genetic Factors, and Social Isolation. We believe that a probable hypothesis of an underlying cause of AD after COVID-19 infection could be the interplay of all these factors.

Meta-Data Analysis to Explore the Hub of the Hub-Genes That Influence SARS-CoV-2 Infections Highlighting Their Pathogenetic Processes and Drugs Repurposing

The pandemic of SARS-CoV-2 infections is a severe threat to human life and the world economic condition. Although vaccination has reduced the outspread, but still the situation is not under control because of the instability of RNA sequence patterns of SARS-CoV-2, which requires effective drugs. Several studies have suggested that the SARS-CoV-2 infection causing hub differentially expressed genes (Hub-DEGs). However, we observed that there was not any common hub gene (Hub-DEGs) in our analyses. Therefore, it may be difficult to take a common treatment plan against SARS-CoV-2 infections globally. The goal of this study was to examine if more representative Hub-DEGs from published studies by means of hub of Hub-DEGs (hHub-DEGs) and associated potential candidate drugs. In this study, we reviewed 41 articles on transcriptomic data analysis of SARS-CoV-2 and found 370 unique hub genes or studied genes in total. Then, we selected 14 more representative Hub-DEGs (AKT1, APP, CXCL8, EGFR, IL6, INS, JUN, MAPK1, STAT3, TNF, TP53, UBA52, UBC, VEGFA) as hHub-DEGs by their protein-protein interaction analysis. Their associated biological functional processes, transcriptional, and post-transcriptional regulatory factors. Then we detected hHub-DEGs guided top-ranked nine candidate drug agents (Digoxin, Avermectin, Simeprevir, Nelfinavir Mesylate, Proscillaridin, Linifanib, Withaferin, Amuvatinib, Atazanavir) by molecular docking and cross-validation for treatment of SARS-CoV-2 infections. Therefore, the findings of this study could be useful in formulating a common treatment plan against SARS-CoV-2 infections globally.