Coronaviral ORF6 protein mediates inter-organelle contacts and modulates host cell lipid flux for virus production.

Lipid droplets (LDs) form inter-organelle contacts with the endoplasmic reticulum (ER) that promote their biogenesis, while LD contacts with mitochondria enhance ß-oxidation of contained fatty acids. Viruses have been shown to take advantage of lipid droplets to promote viral production, but it remains unclear whether they also modulate the interactions between LDs and other organelles. Here, we showed that coronavirus ORF6 protein targets LDs and is localized to the mitochondria-LD and ER-LD contact sites, where it regulates LD biogenesis and lipolysis. At the molecular level, we find that ORF6 inserts into the LD lipid monolayer via its two amphipathic helices. ORF6 further interacts with ER membrane proteins BAP31 and USE1 to mediate ER-LDs contact formation. Additionally, ORF6 interacts with the SAM complex in the mitochondrial outer membrane to link mitochondria to LDs. In doing so, ORF6 promotes cellular lipolysis and LD biogenesis to reprogram host cell lipid flux and facilitate viral production.

Single-cell sequencing of PBMC characterizes the altered transcriptomic landscape of classical monocytes in BNT162b2-induced myocarditis.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been the most dangerous threat to public health worldwide for the last few years, which led to the development of the novel mRNA vaccine (BNT162b2). However, BNT162b2 vaccination is known to be associated with myocarditis. Here, as an attempt to determine the pathogenesis of the disease and to develop biomarkers to determine whether subjects likely proceed to myocarditis after vaccination, we conducted a time series analysis of peripheral blood mononuclear cells of a patient with BNT162b2-induced myocarditis. Single-cell RNA sequence analysis identified monocytes as the cell clusters with the most dynamic changes. To identify distinct gene expression signatures, we compared monocytes of BNT162b2-induced myocarditis with monocytes under various conditions, including SARS-CoV-2 infection, BNT162b2 vaccination, and Kawasaki disease, a disease similar to myocarditis. Representative changes in the transcriptomic profile of classical monocytes include the upregulation of genes related to fatty acid metabolism and downregulation of transcription factor AP-1 activity. This study provides, for the first time, the importance of classical monocytes in the pathogenesis of myocarditis following BNT162b2 vaccination and presents the possibility that vaccination affects monocytes, further inducing their differentiation and infiltration into the heart.

Transcriptionally active nasopharyngeal commensals and opportunistic microbial dynamics define mild symptoms in the COVID 19 vaccination breakthroughs.

The development of COVID 19 vaccines as an effort to mitigate the outbreak, has saved millions of lives globally. However, vaccination breakthroughs have continuously challenged the vaccines' effectiveness and provided incentives to explore facets holding potential to alter vaccination-induced immunity and protection from subsequent infection, especially VOCs (Variants Of Concern). We explored the functional dynamics of nasopharyngeal transcriptionally active microbes (TAMs) between vaccination breakthroughs and unvaccinated SARS-CoV-2 infected individuals. Microbial taxonomic communities were differentially altered with skewed enrichment of bacterial class/genera of Firmicutes and Gammaproteobacteria with grossly reduced phylum Bacteroidetes in vaccination breakthrough individuals. The Bacillus genus was abundant in Firmicutes in vaccination breakthrough whereas Prevotella among Bacteroides dominated the unvaccinated. Also, Pseudomonas and Salmonella of Gammaproteobacteria were overrepresented in vaccination breakthrough, whilst unvaccinated showed presence of several genera, Achromobacter, Bordetella, Burkholderia, Neisseria, Hemophilus, Salmonella and Pseudomonas, belonging to Proteobacteria. At species level, the microbiota of vaccination breakthrough exhibited relatively higher abundance of unique commensals, in comparison to potential opportunistic microbes enrichment in unvaccinated patients' microbiota. Functional metabolic pathways like amino acid biosynthesis, sulphate assimilation, fatty acid and beta oxidation, associated with generation of SCFAs (short chain fatty acids), were enriched in vaccination breakthroughs. Majorly, metabolic pathways of LCFAs biosynthesis (long chain fatty acids; oleate, dodecenoate, palmitoleate, gondoate) were found associated with the unvaccinated. Our research highlights that vaccination decreases the microbial diversity in terms of depleting opportunistic pathogens and increasing the preponderance of commensals with respect to unvaccinated patients. Metabolic pathway analysis substantiates the shift in diversity to functionally modulate immune response generation, which may be related to mild clinical manifestations and faster recovery times during vaccination breakthroughs.

Fatty Acids: Essential Nutrients and Important Biomarkers.

Fatty acids (FA) are well-known, important components of human nutrition [...].

Cardiologic evaluation of Turkish mitochondrial fatty acid oxidation disorders.

BACKGROUND: Mitochondrial fatty acid oxidation disorders (FAODs) cause impairment in energy metabolism and can lead to a spectrum of cardiac pathologies including cardiomyopathy and arrhythmias. The frequency of underlying cardiac pathologies and the response to recommended treatment in FAODs was investigated. METHODS: Sixty-eight children (35 males, 33 females) with the diagnosis of a FAOD were included in the study. Cardiac function was evaluated with 12-lead standard electrocardiography, echocardiography, and 24 h Holter monitoring. RESULTS: Forty-five patients (66%) were diagnosed after disease symptoms developed and 23 patients (34%) were diagnosed in the pre-symptomatic period. Among symptomatic patients (n: 45), cardiovascular findings were detected in 18 (40%) patients, including cardiomyopathy in 14 (31.1%) and conduction abnormalities in 4 (8.8%) patients. Cardiac symptoms were more frequently detected in primary systemic carnitine deficiency (57.1%). Patients with multiple acyl-CoA dehydrogenase, long-chain 3-hydroxyacyl-CoA dehydrogenase, and mitochondrial trifunctional protein deficiencies also had an increased frequency of cardiac symptoms. Patients with medium-chain acyl-CoA dehydrogenase, very long-chain acyl-CoA dehydrogenase, and carnitine palmitoyltransferase I deficiencies had a lower prevalence of cardiac symptoms both during admission and during clinical follow up. Cardiomyopathy resolved completely in 8/14 (57%) patients and partially in 2/14 (14.3%) patients with treatment. Two patients with cardiomyopathy died in the newborn period; cardiomyopathy persisted in 1 (7.1%) patient with very long-chain acyl-CoA dehydrogenase deficiency. CONCLUSION: Early diagnosis, treatment and follow up made a significant contribution to the improvement of cardiac symptoms of patients with FAODs.

Identifying SARS-CoV-2 Drugs Binding to the Spike Fatty Acid Binding Pocket Using In Silico Docking and Molecular Dynamics.

Drugs against novel targets are needed to treat COVID-19 patients, especially as SARS-CoV-2 is capable of rapid mutation. Structure-based de novo drug design and repurposing of drugs and natural products is a rational approach to discovering potentially effective therapies. These in silico simulations can quickly identify existing drugs with known safety profiles that can be repurposed for COVID-19 treatment. Here, we employ the newly identified spike protein free fatty acid binding pocket structure to identify repurposing candidates as potential SARS-CoV-2 therapies. Using a validated docking and molecular dynamics protocol effective at identifying repurposing candidates inhibiting other SARS-CoV-2 molecular targets, this study provides novel insights into the SARS-CoV-2 spike protein and its potential regulation by endogenous hormones and drugs. Some of the predicted repurposing candidates have already been demonstrated experimentally to inhibit SARS-CoV-2 activity, but most of the candidate drugs have yet to be tested for activity against the virus. We also elucidated a rationale for the effects of steroid and sex hormones and some vitamins on SARS-CoV-2 infection and COVID-19 recovery.

Nanopore membrane chip-based isolation method for metabolomic analysis of plasma small extracellular vesicles from COVID-19 survivors.

Multiple studies showed that metabolic disorders play a critical role in respiratory infectious diseases, including COVID-19. Metabolites contained in small extracellular vesicles (sEVs) are different from those in plasma at the acute stage, while the metabolic features of plasma sEVs of COVID-19 survivors remain unknown. Here, we used a nanopore membrane-based microfluidic chip for plasma sEVs separation, termed ExoSEC, and compared the sEVs obtained by UC, REG, and ExoSEC in terms the time, cost, purity, and metabolic features. The results indicated the ExoSEC was much less costly, provided higher purity by particles/proteins ratio, and achieved 205-fold and 2-fold higher sEVs yield, than UC and REG, respectively. Moreover, more metabolites were identified and several signaling pathways were significantly enriched in ExoSEC-sEVs compared to UC-sEVs and REG-sEVs. Furthermore, we detected 306 metabolites in plasma sEVs using ExoSEC from recovered asymptomatic (RA), moderate (RM), and severe/critical COVID-19 (RS) patients without underlying diseases 3 months after discharge. Our study demonstrated that COVID-19 survivors, especially RS, experienced significant metabolic alteration and the dysregulated pathways mainly involved fatty acid biosynthesis, phenylalanine metabolism, etc. Metabolites of the fatty acid biosynthesis pathway bore a significantly negative association with red blood cell counts and hemoglobin, which might be ascribed to hypoxia or respiratory failure in RM and RS but not in RA at the acute stage. Our study confirmed that ExoSEC could provide a practical and economical alternative for high throughput sEVs metabolomic study.

Repurposing SGLT-2 Inhibitors to Target Aging: Available Evidence and Molecular Mechanisms.

Caloric restriction promotes longevity in multiple animal models. Compounds modulating nutrient-sensing pathways have been suggested to reproduce part of the beneficial effect of caloric restriction on aging. However, none of the commonly studied caloric restriction mimetics actually produce a decrease in calories. Sodium-glucose cotransporter 2 inhibitors (SGLT2-i) are a class of drugs which lower glucose by promoting its elimination through urine, thus inducing a net loss of calories. This effect promotes a metabolic shift at the systemic level, fostering ketones and fatty acids utilization as glucose-alternative substrates, and is accompanied by a modulation of major nutrient-sensing pathways held to drive aging, e.g., mTOR and the inflammasome, overall resembling major features of caloric restriction. In addition, preliminary experimental data suggest that SGLT-2i might also have intrinsic activities independent of their systemic effects, such as the inhibition of cellular senescence. Consistently, evidence from both preclinical and clinical studies have also suggested a marked ability of SGLT-2i to ameliorate low-grade inflammation in humans, a relevant driver of aging commonly referred to as inflammaging. Considering also the amount of data from clinical trials, observational studies, and meta-analyses suggesting a tangible effect on age-related outcomes, such as cardiovascular diseases, heart failure, kidney disease, and all-cause mortality also in patients without diabetes, here we propose a framework where at least part of the benefit provided by SGLT-2i is mediated by their ability to blunt the drivers of aging. To support this postulate, we synthesize available data relative to the effect of this class on: 1- animal models of healthspan and lifespan; 2- selected molecular pillars of aging in preclinical models; 3- biomarkers of aging and especially inflammaging in humans; and 4- COVID-19-related outcomes. The burden of evidence might prompt the design of studies testing the potential employment of this class as anti-aging drugs.

Integrated microbiome and metabolome analysis reveals the potential therapeutic mechanism of Qing-Fei-Pai-Du decoction in mice with coronavirus-induced pneumonia.

Current studies have shown that gut microbiota may be closely related to the severity of coronavirus disease 2019 (COVID-19) by regulating the host immune response. Qing-Fei-Pai-Du decoction (QFPDD) is the recommended drug for clinical treatment of patients with COVID-19 in China, but whether it exerts a therapeutic effect by modulating the immune response through gut microbiota remains unclear. In this study, we evaluated the therapeutic effects of QFPDD in pneumonia model mice and performed 16S rRNA sequencing and serum and lung tissue metabolomic analysis to explore the underlying mechanisms during the treatment. Then, Spearman correlation analysis was performed on gut microbiome, serum metabolome, and immune-inflammation-related indicators. Our results suggest that QFPDD can restore the richness and diversity of gut microbiota, and multiple gut microbiota (including Alistipes, Odoribacter, Staphylococcus, Lachnospiraceae_NK4A136_group Enterorhabdus, and unclassified_f_Lachnospiraceae) are significantly associated with immune-inflammation-related indicators. In addition, various types of lipid metabolism changes were observed in serum and lung tissue metabolome, especially glycerophospholipids and fatty acids. A total of 27 differential metabolites (DMs) were significantly correlated with immune-inflammation-related indicators, including 9 glycerophospholipids, 7 fatty acids, 3 linoleic acid, 2 eicosanoids, 2 amino acids, 2 bile acids, and 2 others. Interestingly, these DMs showed a good correlation with the gut microbiota affected by QFPDD. The above results suggest that QFPDD can improve the immune function and reduce inflammation in pneumonia model mice by remodeling gut microbiota and host metabolism.

Peroxisomal very long-chain fatty acid transport is targeted by herpesviruses and the antiviral host response.

Very long-chain fatty acids (VLCFA) are critical for human cytomegalovirus replication and accumulate upon infection. Here, we used Epstein-Barr virus (EBV) infection of human B cells to elucidate how herpesviruses target VLCFA metabolism. Gene expression profiling revealed that, despite a general induction of peroxisome-related genes, EBV early infection decreased expression of the peroxisomal VLCFA transporters ABCD1 and ABCD2, thus impairing VLCFA degradation. The mechanism underlying ABCD1 and ABCD2 repression involved RNA interference by the EBV-induced microRNAs miR-9-5p and miR-155, respectively, causing significantly increased VLCFA levels. Treatment with 25-hydroxycholesterol, an antiviral innate immune modulator produced by macrophages, restored ABCD1 expression and reduced VLCFA accumulation in EBV-infected B-lymphocytes, and, upon lytic reactivation, reduced virus production in control but not ABCD1-deficient cells. Finally, also other herpesviruses and coronaviruses target ABCD1 expression. Because viral infection might trigger neuroinflammation in X-linked adrenoleukodystrophy (X-ALD, inherited ABCD1 deficiency), we explored a possible link between EBV infection and cerebral X-ALD. However, neither immunohistochemistry of post-mortem brains nor analysis of EBV seropositivity in 35 X-ALD children supported involvement of EBV in the onset of neuroinflammation. Collectively, our findings indicate a previously unrecognized, pivotal role of ABCD1 in viral infection and host defence, prompting consideration of other viral triggers in cerebral X-ALD.

Combining metabolome and clinical indicators with machine learning provides some promising diagnostic markers to precisely detect smear-positive/negative pulmonary tuberculosis.

BACKGROUND: Tuberculosis (TB) had been the leading lethal infectious disease worldwide for a long time (2014-2019) until the COVID-19 global pandemic, and it is still one of the top 10 death causes worldwide. One important reason why there are so many TB patients and death cases in the world is because of the difficulties in precise diagnosis of TB using common detection methods, especially for some smear-negative pulmonary tuberculosis (SNPT) cases. The rapid development of metabolome and machine learning offers a great opportunity for precision diagnosis of TB. However, the metabolite biomarkers for the precision diagnosis of smear-positive and smear-negative pulmonary tuberculosis (SPPT/SNPT) remain to be uncovered. In this study, we combined metabolomics and clinical indicators with machine learning to screen out newly diagnostic biomarkers for the precise identification of SPPT and SNPT patients. METHODS: Untargeted plasma metabolomic profiling was performed for 27 SPPT patients, 37 SNPT patients and controls. The orthogonal partial least squares-discriminant analysis (OPLS-DA) was then conducted to screen differential metabolites among the three groups. Metabolite enriched pathways, random forest (RF), support vector machines (SVM) and multilayer perceptron neural network (MLP) were performed using Metaboanalyst 5.0, "caret" R package, "e1071" R package and "Tensorflow" Python package, respectively. RESULTS: Metabolomic analysis revealed significant enrichment of fatty acid and amino acid metabolites in the plasma of SPPT and SNPT patients, where SPPT samples showed a more serious dysfunction in fatty acid and amino acid metabolisms. Further RF analysis revealed four optimized diagnostic biomarker combinations including ten features (two lipid/lipid-like molecules and seven organic acids/derivatives, and one clinical indicator) for the identification of SPPT, SNPT patients and controls with high accuracy (83-93%), which were further verified by SVM and MLP. Among them, MLP displayed the best classification performance on simultaneously precise identification of the three groups (94.74%), suggesting the advantage of MLP over RF/SVM to some extent. CONCLUSIONS: Our findings reveal plasma metabolomic characteristics of SPPT and SNPT patients, provide some novel promising diagnostic markers for precision diagnosis of various types of TB, and show the potential of machine learning in screening out biomarkers from big data.

Phytochemical Discrimination, Biological Activity and Molecular Docking of Water-Soluble Inhibitors from Saussurea costus Herb against Main Protease of SARS-CoV-2.

Siddha medicine is one of the oldest medical systems in the world and is believed to have originated more than 10,000 years ago and is prevalent across ancient Tamil land. It is undeniable that inhibitor preferences rise with increasing solubility in water due to the considerations pertaining to the bioavailability and the ease of which unabsorbed residues can be disposed of. In this study, we showed the phytochemical discrimination of Saussurea costus extracted with water at room temperature as a green extraction procedure. A total of 48 compounds were identified using gas chromatography-mass spectrometry (GC-MS). The fatty acids had a high phytochemical abundance at 73.8%, followed by tannins at 8.2%, carbohydrates at 6.9%, terpenoids at 4.3%, carboxylic acids at 2.5%, hydrocarbons at 2.4%, phenolic compounds at 0.2%, and sterols at 1.5%. Of these compounds, 22 were docked on the active side and on the catalytic dyad of His41 and Cys145 of the main protease of SARS-CoV-2 (Mpro). Eight active inhibitors were carbohydrates, five were fatty acids, three were terpenoids, two were carboxylic acids, one was a tannin, one was a phenolic compound, and one was a sterol. The best inhibitors were 4,8,13-Cyclotetradecatriene-1,3-diol, 1,5,9-trimethyl-12-(1-methylethyl), Andrographolide, and delta.4-Androstene-3.beta.,17.beta.-diol, with a binding affinity that ranged from -6.1 kcal/mol to -6.5 kcal/mol. The inhibitory effect of Saussurea costus of SARS-CoV-2 entry into the cell was studied using a pseudovirus with Spike proteins from the D614G variant and the VOC variants Gamma and Delta. Based on the viral cycle of SARS-CoV-2, our results suggest that the Saussurea costus aqueous extract has no virucidal effect and inhibits the virus in the events after cell entry. Furthermore, the biological activity of the aqueous extract was investigated against HSV-1 virus and two bacterial strains, namely Staphylococcus aureus ATCC BAA 1026 and Escherichia coli ATCC 9637. According to this study, an enormous number of water-soluble inhibitors were identified from Saussurea costus against the Mpro, and this is unprecedented as far as we know.

Expanding the antiviral potential of the mosquito lipid-transfer protein AEG12 against SARS-CoV-2 using hydrophobic antiviral ligands.

The mosquito protein AEG12 encompasses a large (~ 3800 Å3 ) hydrophobic cavity which binds and delivers unsaturated fatty acids into biological membranes, allowing it to lyse cells and neutralize a wide range of enveloped viruses. Herein, the lytic and antiviral activities are modified with non-naturally occurring lipid ligands. We generated novel AEG12 complexes in which the endogenous fatty acid ligands were replaced with hydrophobic viral inhibitors. The resulting compounds modulated cytotoxicity and infectivity against SARS-CoV-2, potentially reflecting additional mechanisms of action beyond membrane destabilization. These studies provide valuable insight into the design of novel broad-spectrum antiviral therapeutics centred on the AEG12 protein scaffold as a delivery vehicle for hydrophobic therapeutic compounds.

Assay of Fatty Acids and Their Role in the Prevention and Treatment of COVID-19.

Since the emergence of COVID-19, concerted worldwide efforts have taken place to minimize global spread of the contagion. Its widespread effects have also facilitated evolution of new strains, such as the delta and omicron variants, which emerged toward the end of 2020 and 2021, respectively. While these variants appear to be no more deadly than the previous alpha, beta, and gamma strains, and widespread population vaccinations notwithstanding, greater virulence makes the challenge of minimizing spread even greater. One of the peculiarities of this virus is the extreme heath impacts, with the great majority of individuals minimally affected, even sometimes unaware of infection, while for a small minority, it is deadly or produces diverse long-term effects. Apart from vaccination, another approach has been an attempt to identify treatments, for those individuals for whom the virus represents a threat of particularly severe health impact(s). These treatments include anti-SARS-CoV-2 monoclonal antibodies, anticoagulant therapies, interleukin inhibitors, and anti-viral agents such as remdesivir. Nutritional factors are also under consideration, and a variety of clinical trials are showing promise for the use of specific fatty acids, or related compounds such as fat-soluble steroid vitamin D, to mitigate the more lethal aspects of COVID-19 by modulating inflammation and by anti-viral effects. Here we explore the potential protective role of fatty acids as a potential prophylactic as well as remedial treatment during viral infections, particularly COVID-19. We present a multiplexed method for the analysis of free and phospholipid bound fatty acids, which may facilitate research into the role of fatty acids as plasma biomarkers and therapeutic agents in minimizing pre- and post-infection health impacts.

Acetylcholine, Fatty Acids, and Lipid Mediators Are Linked to COVID-19 Severity.

Lipid and cholinergic mediators are inflammatory regulators, but their role in the immunopathology of COVID-19 is still unclear. Here, we used human blood and tracheal aspirate (TA) to investigate whether acetylcholine (Ach), fatty acids (FAs), and their derived lipid mediators (LMs) are associated with COVID-19 severity. First, we analyzed the perturbation profile induced by SARS-CoV-2 infection in the transcriptional profile of genes related to the ACh and FA/LM pathways. Blood and TA were used for metabolomic and lipidomic analyses and for quantification of leukocytes, cytokines, and ACh. Differential expression and coexpression gene network data revealed a unique transcriptional profile associated with ACh and FA/LM production, release, and cellular signaling. Transcriptomic data were corroborated by laboratory findings: SARS-CoV-2 infection increased plasma and TA levels of arachidonic acid, 5-hydroxy-6E,8Z,11Z,14Z-eicosatetraenoic acid, 11-hydroxy-5Z,8Z,12E,14Z-eicosatetraenoic acid, and ACh. TA samples also exhibited high levels of PGE2, thromboxane B2, 12-oxo-5Z,8Z,10E,14Z-eicosatetraenoic acid, and 6-trans-leukotriene B4 Bioinformatics and experimental approaches demonstrated robust correlation between transcriptional profile in Ach and FA/LM pathways and parameters of severe COVID-19. As expected, the increased neutrophil-to-lymphocyte ratio, neutrophil counts, and cytokine levels (IL-6, IL-10, IL-1ß, and IL-8) correlated with worse clinical scores. Glucocorticoids protected severe and critical patients and correlated with reduced Ach levels in plasma and TA samples. We demonstrated that pulmonary and systemic hyperinflammation in severe COVID-19 are associated with high levels of Ach and FA/LM. Glucocorticoids favored the survival of patients with severe/critical disease, and this effect was associated with a reduction in ACh levels.

Comparison of BMIPP-SPECT/CT to 18FDG-PET/CT for Imaging Brown or Browning Fat in a Preclinical Model.

Obesity is a leading cause of preventable death and morbidity. To elucidate the mechanisms connecting metabolically active brown adipose tissue (BAT) and metabolic health may provide insights into methods of treatment for obesity-related conditions. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18FDG-PET/CT) is traditionally used to image human BAT activity. However, the primary energy source of BAT is derived from intracellular fatty acids and not glucose. Beta-methyl-p-iodophenylpentadecanoic acid (BMIPP) is a fatty acid analogue amenable to in vivo imaging by single photon emission computed tomography/CT (SPECT/CT) when radiolabeled with iodine isotopes. In this study, we compare the use of 18FDG-PET/CT and 125I-BMIPP-SPECT/CT for fat imaging to ascertain whether BMIPP is a more robust candidate for the non-invasive evaluation of metabolically active adipose depots. Interscapular BAT, inguinal white adipose tissue (iWAT), and gonadal white adipose tissue (gWAT) uptake of 18FDG and 125I-BMIPP was quantified in mice following treatment with the BAT-stimulating drug CL-316,243 or saline vehicle control. After CL-316,243 treatment, uptake of both radiotracers increased in BAT and iWAT. The standard uptake value (SUVmean) for 18FDG and 125I-BMIPP significantly correlated in these depots, although uptake of 125I-BMIPP in BAT and iWAT more closely mimicked the fold-change in metabolic rate as measured by an extracellular flux analyzer. Herein, we find that imaging BAT with the radioiodinated fatty acid analogue BMIPP yields more physiologically relevant data than 18FDG-PET/CT, and its conventional use may be a pivotal tool for evaluating BAT in both mice and humans.

Molecular Dynamics of DHHC20 Acyltransferase Suggests Principles of Lipid and Protein Substrate Selectivity.

Lipid modification of viral proteins with fatty acids of different lengths (S-acylation) is crucial for virus pathogenesis. The reaction is catalyzed by members of the DHHC family and proceeds in two steps: the autoacylation is followed by the acyl chain transfer onto protein substrates. The crystal structure of human DHHC20 (hDHHC20), an enzyme involved in the acylation of S-protein of SARS-CoV-2, revealed that the acyl chain may be inserted into a hydrophobic cavity formed by four transmembrane (TM) α-helices. To test this model, we used molecular dynamics of membrane-embedded hDHHC20 and its mutants either in the absence or presence of various acyl-CoAs. We found that among a range of acyl chain lengths probed only C16 adopts a conformation suitable for hDHHC20 autoacylation. This specificity is altered if the small or bulky residues at the cavity's ceiling are exchanged, e.g., the V185G mutant obtains strong preferences for binding C18. Surprisingly, an unusual hydrophilic ridge was found in TM helix 4 of hDHHC20, and the responsive hydrophilic patch supposedly involved in association was found in the 3D model of the S-protein TM-domain trimer. Finally, the exchange of critical Thr and Ser residues in the spike led to a significant decrease in its S-acylation. Our data allow further development of peptide/lipid-based inhibitors of hDHHC20 that might impede replication of Corona- and other enveloped viruses.

Long COVID and long chain fatty acids (LCFAs): Psychoneuroimmunity implication of omega-3 LCFAs in delayed consequences of COVID-19.

The global spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to the lasting pandemic of coronavirus disease 2019 (COVID-19) and the post-acute phase sequelae of heterogeneous negative impacts in multiple systems known as the "long COVID." The mechanisms of neuropsychiatric complications of long COVID are multifactorial, including long-term tissue damages from direct CNS viral involvement, unresolved systemic inflammation and oxidative stress, maladaptation of the renin-angiotensin-aldosterone system and coagulation system, dysregulated immunity, the dysfunction of neurotransmitters and hypothalamus-pituitaryadrenal (HPA) axis, and the psychosocial stress imposed by societal changes in response to this pandemic. The strength of safety, well-acceptance, and accumulating scientific evidence has now afforded nutritional medicine a place in the mainstream of neuropsychiatric intervention and prophylaxis. Long chain omega-3 polyunsaturated fatty acids (omega-3 or n-3 PUFAs) might have favorable effects on immunity, inflammation, oxidative stress and psychoneuroimmunity at different stages of SARS-CoV-2 infection. Omega-3 PUFAs, particularly EPA, have shown effects in treating mood and neurocognitive disorders by reducing pro-inflammatory cytokines, altering the HPA axis, and modulating neurotransmission via lipid rafts. In addition, omega-3 PUFAs and their metabolites, including specialized pro-resolvin mediators, accelerate the process of cleansing chronic inflammation and restoring tissue homeostasis, and therefore offer a promising strategy for Long COVID. In this article, we explore in a systematic review the putative molecular mechanisms by which omega-3 PUFAs and their metabolites counteract the negative effects of long COVID on the brain, behavior, and immunity.

The effect of polyunsaturated fatty acids on the severity and mortality of COVID patients: A systematic review.

BACKGROUND: Covid-19 mortality is largely associated with a severe increase in inflammatory cytokines and polyunsaturated fatty acids (PUFAs) play an important role in modulating immune pathways and inflammatory responses; so this study was done to evaluate the effect of polyunsaturated fatty acids on the prognosis of Covid-19 disease. METHODS AND MATERIALS: A comprehensive search was conducted in PubMed, Scopus and Web of Science. For systematic identification, the search was performed based on the following keywords COVID-19, SARS-CoV-2, COVID, Coronavirus Disease 19, SARS COV- 2 Infection, SARS-CoV-2, COVID19, Coronavirus Disease, Fatty Acids, Omega-3, Omega-3 Fatty Acid, Omega-6, n 3 Fatty and Omega-9 in the mentioned databases, using OR, and AND. All searched articles were included in the study and retrieved, and End-Note X7 software was used to manage the studies. RESULTS: Findings on the relationship between omega-3 and omega-6 fatty acids and the risk of Covid-19 are various, but omega-3 supplements have been found to be 12 to 21% effective in reducing the risk of Covid-19. Most studies emphasized the increasing severity of the disease and the need for mechanical ventilation and hospitalization due to polyunsaturated fatty acid deficiency. It is also demonstrated that omega-3 fatty acid deficiency increased mortality in patients with Covid-19. However, there is also a warning that in critical cases, elevated levels of fatty acids in patients' lungs and a cytokine storm are the main reasons for mortality in Covid-19 patients. CONCLUSION: Polyunsaturated fatty acids can reduce the risk of covid-19 which could be considered as a preventative, inexpensive and safe method. However, the risk of taking high-dose omega-3 supplements before or during SARS-COV-2 infection needs to be investigated.

Synthetic virions reveal fatty acid-coupled adaptive immunogenicity of SARS-CoV-2 spike glycoprotein.

SARS-CoV-2 infection is a major global public health concern with incompletely understood pathogenesis. The SARS-CoV-2 spike (S) glycoprotein comprises a highly conserved free fatty acid binding pocket (FABP) with unknown function and evolutionary selection advantage1,2. Deciphering FABP impact on COVID-19 progression is challenged by the heterogenous nature and large molecular variability of live virus. Here we create synthetic minimal virions (MiniVs) of wild-type and mutant SARS-CoV-2 with precise molecular composition and programmable complexity by bottom-up assembly. MiniV-based systematic assessment of S free fatty acid (FFA) binding reveals that FABP functions as an allosteric regulatory site enabling adaptation of SARS-CoV-2 immunogenicity to inflammation states via binding of pro-inflammatory FFAs. This is achieved by regulation of the S open-to-close equilibrium and the exposure of both, the receptor binding domain (RBD) and the SARS-CoV-2 RGD motif that is responsible for integrin co-receptor engagement. We find that the FDA-approved drugs vitamin K and dexamethasone modulate S-based cell binding in an FABP-like manner. In inflammatory FFA environments, neutralizing immunoglobulins from human convalescent COVID-19 donors lose neutralization activity. Empowered by our MiniV technology, we suggest a conserved mechanism by which SARS-CoV-2 dynamically couples its immunogenicity to the host immune response.