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1.
Commun Biol ; 5(1): 764, 2022 Jul 29.
Article in English | MEDLINE | ID: covidwho-1967632

ABSTRACT

Mammalian organs are individually controlled by autonomous circadian clocks. At the molecular level, this process is defined by the cyclical co-expression of both core transcription factors and their downstream targets across time. While interactions between these molecular clocks are necessary for proper homeostasis, these features remain undefined. Here, we utilize integrative analysis of a baboon diurnal transcriptome atlas to characterize the properties of gene networks under circadian control. We found that 53.4% (8120) of baboon genes are oscillating body-wide. Additionally, two basic network modes were observed at the systems level: daytime and nighttime mode. Daytime networks were enriched for genes involved in metabolism, while nighttime networks were enriched for genes associated with growth and cellular signaling. A substantial number of diseases only form significant disease modules at either daytime or nighttime. In addition, a majority of SARS-CoV-2-related genes and modules are rhythmically expressed, which have significant network proximities with circadian regulators. Our data suggest that synchronization amongst circadian gene networks is necessary for proper homeostatic functions and circadian regulators have close interactions with SARS-CoV-2 infection.


Subject(s)
COVID-19 , Gene Regulatory Networks , Animals , COVID-19/genetics , Circadian Rhythm/genetics , Mammals/genetics , Primates/genetics , SARS-CoV-2
2.
Int J Mol Sci ; 23(14)2022 Jul 20.
Article in English | MEDLINE | ID: covidwho-1964013

ABSTRACT

Iron is a crucial element for mammalian cells, considering its intervention in several physiologic processes. Its homeostasis is finely regulated, and its alteration could be responsible for the onset of several disorders. Iron is closely related to inflammation; indeed, during inflammation high levels of interleukin-6 cause an increased production of hepcidin which induces a degradation of ferroportin. Ferroportin degradation leads to decreased iron efflux that culminates in elevated intracellular iron concentration and consequently iron toxicity in cells and tissues. Therefore, iron chelation could be considered a novel and useful therapeutic strategy in order to counteract the inflammation in several autoimmune and inflammatory diseases. Several iron chelators are already known to have anti-inflammatory effects, among them deferiprone, deferoxamine, deferasirox, and Dp44mT are noteworthy. Recently, eltrombopag has been reported to have an important role in reducing inflammation, acting both directly by chelating iron, and indirectly by modulating iron efflux. This review offers an overview of the possible novel biological effects of the iron chelators in inflammation, suggesting them as novel anti-inflammatory molecules.


Subject(s)
Iron Overload , Animals , Benzoates/therapeutic use , Deferasirox/therapeutic use , Deferiprone , Deferoxamine/therapeutic use , Inflammation/complications , Inflammation/drug therapy , Iron/therapeutic use , Iron Chelating Agents/pharmacology , Iron Chelating Agents/therapeutic use , Iron Overload/drug therapy , Iron Overload/etiology , Mammals , Pyridones/therapeutic use
3.
Int J Mol Sci ; 23(14)2022 Jul 09.
Article in English | MEDLINE | ID: covidwho-1964001

ABSTRACT

Despite the growing list of identified SARS-CoV-2 receptors, the human angiotensin-converting enzyme 2 (ACE2) is still viewed as the main cell entry receptor mediating SARS-CoV-2 internalization. It has been reported that wild-type mice, like other rodent species of the Muridae family, cannot be infected with SARS-CoV-2 due to differences in their ACE2 receptors. On the other hand, the consensus heparin-binding motif of SARS-CoV-2's spike protein, PRRAR, enables the attachment to rodent heparan sulfate proteoglycans (HSPGs), including syndecans, a transmembrane HSPG family with a well-established role in clathrin- and caveolin-independent endocytosis. As mammalian syndecans possess a relatively conserved structure, we analyzed the cellular uptake of inactivated SARS-CoV-2 particles in in vitro and in vivo mice models. Cellular studies revealed efficient uptake into murine cell lines with established syndecan-4 expression. After intravenous administration, inactivated SARS-CoV-2 was taken up by several organs in vivo and could also be detected in the brain. Internalized by various tissues, inactivated SARS-CoV-2 raised tissue TNF-α levels, especially in the heart, reflecting the onset of inflammation. Our studies on in vitro and in vivo mice models thus shed light on unknown details of SARS-CoV-2 internalization and help broaden the understanding of the molecular interactions of SARS-CoV-2.


Subject(s)
COVID-19 , SARS-CoV-2 , Tissue Distribution , Virus Internalization , Angiotensin-Converting Enzyme 2/metabolism , Animals , COVID-19/metabolism , COVID-19/virology , Heparan Sulfate Proteoglycans/metabolism , Humans , Mammals/metabolism , Mice , SARS-CoV-2/metabolism , Syndecans/metabolism , Tissue Distribution/physiology
4.
Cells ; 11(13)2022 06 21.
Article in English | MEDLINE | ID: covidwho-1963752

ABSTRACT

Glucose-6-phosphate dehydrogenase (G6PD) is the second rate-limiting enzyme of the pentose phosphate pathway. This enzyme is present in the cytoplasm of all mammalian cells, and its activity is essential for an adequate functioning of the antioxidant system and for the response of innate immunity. It is responsible for the production of nicotinamide adenine dinucleotide phosphate (NADPH), the first redox equivalent, in the pentose phosphate pathway. Viral infections such as SARS-CoV-2 may induce the Warburg effect with an increase in anaerobic glycolysis and production of lactate. This condition ensures the success of viral replication and production of the virion. Therefore, the activity of G6PD may be increased in COVID-19 patients raising the level of the NADPH, which is needed for the enzymatic and non-enzymatic antioxidant systems that counteract the oxidative stress caused by the cytokine storm. G6PD deficiency affects approximately 350-400 million people worldwide; therefore, it is one of the most prevalent diseases related to enzymatic deficiency worldwide. In G6PD-deficient patients exposed to SARS-CoV-2, the amount of NADPH is reduced, increasing the susceptibility for viral infection. There is loss of the redox homeostasis in them, resulting in severe pneumonia and fatal outcomes.


Subject(s)
COVID-19 , Glucosephosphate Dehydrogenase , Animals , Antioxidants , Glucosephosphate Dehydrogenase/metabolism , Humans , Mammals/metabolism , NADP/metabolism , SARS-CoV-2
5.
Cells ; 11(15)2022 Jul 22.
Article in English | MEDLINE | ID: covidwho-1957235

ABSTRACT

Autophagy is a highly conserved lysosomal degradation pathway active at basal levels in all cells. However, under stress conditions, such as a lack of nutrients or trophic factors, it works as a survival mechanism that allows the generation of metabolic precursors for the proper functioning of the cells until the nutrients are available. Neurons, as post-mitotic cells, depend largely on autophagy to maintain cell homeostasis to get rid of damaged and/or old organelles and misfolded or aggregated proteins. Therefore, the dysfunction of this process contributes to the pathologies of many human diseases. Furthermore, autophagy is highly active during differentiation and development. In this review, we describe the current knowledge of the different pathways, molecular mechanisms, factors that induce it, and the regulation of mammalian autophagy. We also discuss its relevant role in development and disease. Finally, here we summarize several investigations demonstrating that autophagic abnormalities have been considered the underlying reasons for many human diseases, including liver disease, cardiovascular, cerebrovascular diseases, neurodegenerative diseases, neoplastic diseases, cancers, and, more recently, infectious diseases, such as SARS-CoV-2 caused COVID-19 disease.


Subject(s)
COVID-19 , Animals , Autophagy/physiology , Homeostasis , Humans , Lysosomes/metabolism , Mammals , SARS-CoV-2
6.
J Cell Biol ; 221(7)2022 Jul 04.
Article in English | MEDLINE | ID: covidwho-1956550

ABSTRACT

The process of membrane atg8ylation, defined herein as the conjugation of the ATG8 family of ubiquitin-like proteins to membrane lipids, is beginning to be appreciated in its broader manifestations, mechanisms, and functions. Classically, membrane atg8ylation with LC3B, one of six mammalian ATG8 family proteins, has been viewed as the hallmark of canonical autophagy, entailing the formation of characteristic double membranes in the cytoplasm. However, ATG8s are now well described as being conjugated to single membranes and, most recently, proteins. Here we propose that the atg8ylation is coopted by multiple downstream processes, one of which is canonical autophagy. We elaborate on these biological outputs, which impact metabolism, quality control, and immunity, emphasizing the context of inflammation and immunological effects. In conclusion, we propose that atg8ylation is a modification akin to ubiquitylation, and that it is utilized by different systems participating in membrane stress responses and membrane remodeling activities encompassing autophagy and beyond.


Subject(s)
Autophagy , Ubiquitins , Animals , Autophagy/physiology , Autophagy-Related Protein 8 Family/genetics , Autophagy-Related Protein 8 Family/metabolism , Autophagy-Related Proteins/genetics , Autophagy-Related Proteins/metabolism , Mammals/metabolism , Microtubule-Associated Proteins/metabolism , Ubiquitination , Ubiquitins/genetics
7.
J Biomed Nanotechnol ; 18(4): 1121-1130, 2022 Apr 01.
Article in English | MEDLINE | ID: covidwho-1950558

ABSTRACT

Coronavirus disease (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused significant death, economic crisis, and the world to almost completely shut down. This present study focused on targeting the novel SARS-CoV-2 envelope protein, which has not been frequently mutating, and the S protein with a much larger peptide capable of inhibiting virus-mammalian cell attraction. In doing so, molecular dynamics software was used here to model six peptides including: NapFFTLUFLTUTE, NapFFSLAFLTATE, NapFFSLUFLSUTE, NapFFTLAFLTATE, NapFFSLUFLSUSE, and NapFFMLUFLMUME. Results showed that two of these completely hydrophobic peptides (NapFFTLUFLTUTE and NapFFMLUFLMUME) had a strong ability to bind to the virus, preventing its binding to a mammalian cell membrane, entering the cell, and replicating by covering many cell attachment sites on SARS-CoV-2. Further cell modeling results demonstrated the low toxicity and suitable pharmacokinetic properties of both peptides making them ideal for additional in vitro and in vivo investigation. In this manner, these two peptides should be further explored for a wide range of present and future COVID-19 therapeutic and prophylactic applications.


Subject(s)
COVID-19 , Nanostructures , Amino Acid Sequence , Animals , Mammals/metabolism , Peptides , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism
8.
Cells ; 11(13)2022 Jun 23.
Article in English | MEDLINE | ID: covidwho-1933986

ABSTRACT

Two pore channels (TPCs) are implicated in vesicle trafficking, virus infection, and autophagy regulation. As Na+- or Ca2+-permeable channels, TPCs have been reported to be activated by NAADP, PI(3,5)P2, and/or high voltage. However, a comparative study on the function and regulation of the three mammalian TPC subtypes is currently lacking. Here, we used the electrophysiological recording of enlarged endolysosome vacuoles, inside-out and outside-out membrane patches to examine the three TPCs of rabbit (Oryctolagus cuniculus, or Oc) heterologously expressed in HEK293 cells. While PI(3,5)P2 evoked Na+ currents with a potency order of OcTPC1 > OcTPC3 > OcTPC2, only OcTPC2 displayed a strict dependence on PI(3,5)P2. Both OcTPC1 and OcTPC3 were activatable by PI3P and OcTPC3 was also activated by additional phosphoinositide species. While OcTPC2 was voltage-independent, OcTPC1 and OcTPC3 showed voltage dependence with OcTPC3 depending on high positive voltages. Finally, while OcTPC2 preferred a luminal pH of 4.6-6.0 in endolysosomes, OcTPC1 was strongly inhibited by extracytosolic pH 5.0 in both voltage-dependent and -independent manners, and OcTPC3 was inhibited by pH 6.0 but potentiated by pH 8.0. Thus, the three OcTPCs form phosphoinositide-activated Na+ channels with different ligand selectivity, voltage dependence, and extracytosolic pH sensitivity, which likely are optimally tuned for function in specific endolysosomal populations.


Subject(s)
Lysosomes , Phosphatidylinositols , Animals , HEK293 Cells , Humans , Hydrogen-Ion Concentration , Ions , Mammals , Phosphatidylinositol Phosphates , Rabbits
9.
Int J Mol Sci ; 23(13)2022 Jul 05.
Article in English | MEDLINE | ID: covidwho-1934138

ABSTRACT

Long-chain noncoding RNAs (lncRNAs) are RNAs that do not code for proteins, widely present in eukaryotes. They regulate gene expression at multiple levels through different mechanisms at epigenetic, transcription, translation, and the maturation of mRNA transcripts or regulation of the chromatin structure, and compete with microRNAs for binding to endogenous RNA. Adipose tissue is a large and endocrine-rich functional tissue in mammals. Excessive accumulation of white adipose tissue in mammals can cause metabolic diseases. However, unlike white fat, brown and beige fats release energy as heat. In recent years, many lncRNAs associated with adipogenesis have been reported. The molecular mechanisms of how lncRNAs regulate adipogenesis are continually investigated. In this review, we discuss the classification of lncRNAs according to their transcriptional location. lncRNAs that participate in the adipogenesis of white or brown fats are also discussed. The function of lncRNAs as decoy molecules and RNA double-stranded complexes, among other functions, is also discussed.


Subject(s)
Adipogenesis , RNA, Long Noncoding , Adipocytes/metabolism , Adipocytes, Brown/metabolism , Adipogenesis/genetics , Adipose Tissue, Brown/metabolism , Adipose Tissue, White/metabolism , Animals , Mammals/metabolism , RNA, Long Noncoding/genetics , RNA, Long Noncoding/metabolism
10.
Sci Rep ; 12(1): 10027, 2022 Jun 15.
Article in English | MEDLINE | ID: covidwho-1921705

ABSTRACT

High yield production of recombinant HIV SOSIP envelope (Env) trimers has proven elusive as numerous disulfide bonds, proteolytic cleavage and extensive glycosylation pose high demands on the host cell machinery and stress imposed by accumulation of misfolded proteins may ultimately lead to cellular toxicity. The present study utilized the Nicotiana benthamiana/p19 (N.b./p19) transient plant system to assess co-expression of two ER master regulators and 5 chaperones, crucial in the folding process, to enhance yields of three Env SOSIPs, single chain BG505 SOSIP.664 gp140, CH505TF.6R.SOSIP.664.v4.1 and CH848-10.17-DT9. Phenotypic changes in leaves induced by SOSIP expression were employed to rapidly identify chaperone-assisted improvement in health and expression. Up to 15-fold increases were obtained by co-infiltration of peptidylprolvl isomerase (PPI) and calreticulin (CRT) which were further enhanced by addition of the ER-retrieval KDEL tags to the SOSIP genes; levels depending on individual SOSIP type, day of harvest and chaperone gene dosage. Results are consistent with reducing SOSIP misfolding and cellular stress due to increased exposure to the plant host cell's calnexin/calreticulin network and accelerating the rate-limiting cis-trans isomerization of Xaa-Pro peptide bonds respectively. Plant transient co-expression facilitates rapid identification of host cell factors and will be translatable to other complex glycoproteins and mammalian expression systems.


Subject(s)
HIV Infections , HIV-1 , Animals , Antibodies, Neutralizing/metabolism , Calreticulin/genetics , Calreticulin/metabolism , HIV Antibodies/metabolism , HIV-1/genetics , Mammals/metabolism , Peptidylprolyl Isomerase/metabolism , Protein Multimerization , env Gene Products, Human Immunodeficiency Virus/metabolism
11.
Cell Rep ; 40(3): 111117, 2022 Jul 19.
Article in English | MEDLINE | ID: covidwho-1914214

ABSTRACT

As an enveloped virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) delivers its viral genome into host cells via fusion of the viral and cell membranes. Here, we show that ANO6/TMEM16F-mediated cell surface exposure of phosphatidylserine is critical for SARS-CoV-2 entry and that ANO6-selective inhibitors are effective against SARS-CoV-2 infections. Application of the SARS-CoV-2 Spike pseudotyped virus (SARS2-PsV) evokes a cytosolic Ca2+ elevation and ANO6-dependent phosphatidylserine externalization in ACE2/TMPRSS2-positive mammalian cells. A high-throughput screening of drug-like chemical libraries identifies three different structural classes of chemicals showing ANO6 inhibitory effects. Among them, A6-001 displays the highest potency and ANO6 selectivity and it inhibits the single-round infection of SARS2-PsV in ACE2/TMPRSS2-positive HEK 293T cells. More importantly, A6-001 strongly inhibits authentic SARS-CoV-2-induced phosphatidylserine scrambling and SARS-CoV-2 viral replications in Vero, Calu-3, and primarily cultured human nasal epithelial cells. These results provide mechanistic insights into the viral entry process and offer a potential target for pharmacological intervention to protect against coronavirus disease 2019 (COVID-19).


Subject(s)
COVID-19 , Angiotensin-Converting Enzyme 2 , Animals , Anoctamins , COVID-19/drug therapy , Humans , Mammals/metabolism , Phosphatidylserines , Phospholipid Transfer Proteins/metabolism , SARS-CoV-2 , Virus Internalization
12.
Nat Commun ; 13(1): 3714, 2022 06 28.
Article in English | MEDLINE | ID: covidwho-1908171

ABSTRACT

Proteins can be empowered via SpyTag for anchoring and nanoassembly, through covalent bonding to SpyCatcher partners. Here we generate a switchable version of SpyCatcher, allowing gentle purification of SpyTagged proteins. We introduce numerous histidines adjacent to SpyTag's binding site, giving moderate pH-dependent release. After phage-based selection, our final SpySwitch allows purification of SpyTag- and SpyTag003-fusions from bacterial or mammalian culture by capture at neutral pH and release at pH 5, with purity far beyond His-tag methods. SpySwitch is also thermosensitive, capturing at 4 °C and releasing at 37 °C. With flexible choice of eluent, SpySwitch-purified proteins can directly assemble onto multimeric scaffolds. 60-mer multimerization enhances immunogenicity and we use SpySwitch to purify receptor-binding domains from SARS-CoV-2 and 11 other sarbecoviruses. For these receptor-binding domains we determine thermal resilience (for mosaic vaccine development) and cross-recognition by antibodies. Antibody EY6A reacts across all tested sarbecoviruses, towards potential application against new coronavirus pandemic threats.


Subject(s)
COVID-19 , Hot Temperature , Animals , Antibodies , Hydrogen-Ion Concentration , Mammals , SARS-CoV-2
13.
Signal Transduct Target Ther ; 7(1): 199, 2022 06 25.
Article in English | MEDLINE | ID: covidwho-1908147

ABSTRACT

Pseudomonas aeruginosa (P. aeruginosa) is a Gram-negative opportunistic pathogen that infects patients with cystic fibrosis, burn wounds, immunodeficiency, chronic obstructive pulmonary disorder (COPD), cancer, and severe infection requiring ventilation, such as COVID-19. P. aeruginosa is also a widely-used model bacterium for all biological areas. In addition to continued, intense efforts in understanding bacterial pathogenesis of P. aeruginosa including virulence factors (LPS, quorum sensing, two-component systems, 6 type secretion systems, outer membrane vesicles (OMVs), CRISPR-Cas and their regulation), rapid progress has been made in further studying host-pathogen interaction, particularly host immune networks involving autophagy, inflammasome, non-coding RNAs, cGAS, etc. Furthermore, numerous technologic advances, such as bioinformatics, metabolomics, scRNA-seq, nanoparticles, drug screening, and phage therapy, have been used to improve our understanding of P. aeruginosa pathogenesis and host defense. Nevertheless, much remains to be uncovered about interactions between P. aeruginosa and host immune responses, including mechanisms of drug resistance by known or unannotated bacterial virulence factors as well as mammalian cell signaling pathways. The widespread use of antibiotics and the slow development of effective antimicrobials present daunting challenges and necessitate new theoretical and practical platforms to screen and develop mechanism-tested novel drugs to treat intractable infections, especially those caused by multi-drug resistance strains. Benefited from has advancing in research tools and technology, dissecting this pathogen's feature has entered into molecular and mechanistic details as well as dynamic and holistic views. Herein, we comprehensively review the progress and discuss the current status of P. aeruginosa biophysical traits, behaviors, virulence factors, invasive regulators, and host defense patterns against its infection, which point out new directions for future investigation and add to the design of novel and/or alternative therapeutics to combat this clinically significant pathogen.


Subject(s)
COVID-19 , Pseudomonas Infections , Animals , Drug Resistance, Microbial , Humans , Mammals/metabolism , Pseudomonas Infections/drug therapy , Pseudomonas Infections/genetics , Pseudomonas aeruginosa/genetics , Technology , Virulence Factors/genetics , Virulence Factors/metabolism , Virulence Factors/pharmacology
14.
Immunogenetics ; 74(1): 149-165, 2022 02.
Article in English | MEDLINE | ID: covidwho-1906024

ABSTRACT

Birds are important hosts for many RNA viruses, including influenza A virus, Newcastle disease virus, West Nile virus and coronaviruses. Innate defense against RNA viruses in birds involves detection of viral RNA by pattern recognition receptors. Several receptors of different classes are involved, such as endosomal toll-like receptors and cytoplasmic retinoic acid-inducible gene I-like receptors, and their downstream adaptor proteins. The function of these receptors and their antagonism by viruses is well established in mammals; however, this has received less attention in birds. These receptors have been characterized in a few bird species, and the completion of avian genomes will permit study of their evolution. For each receptor, functional work has established ligand specificity and activation by viral infection. Engagement of adaptors, regulation by modulators and the supramolecular organization of proteins required for activation are incompletely understood in both mammals and birds. These receptors bind conserved nucleic acid agonists such as single- or double-stranded RNA and generally show purifying selection, particularly the ligand binding regions. However, in birds, these receptors and adaptors differ between species, and between individuals, suggesting that they are under selection for diversification over time. Avian receptors and signalling pathways, like their mammalian counterparts, are targets for antagonism by a variety of viruses, intent on escape from innate immune responses.


Subject(s)
Influenza A virus , RNA , Animals , Birds/genetics , Humans , Immunity, Innate/genetics , Influenza A virus/genetics , Ligands , Mammals/genetics
15.
Virol J ; 19(1): 112, 2022 06 27.
Article in English | MEDLINE | ID: covidwho-1905664

ABSTRACT

BACKGROUND: Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe respiratory disease in humans, with a case fatality rate of approximately 35%, thus posing a considerable threat to public health. The lack of approved vaccines or antivirals currently constitutes a barrier in controlling disease outbreaks and spread. METHODS: In this study, using a mammalian expression system, which is advantageous for maintaining correct protein glycosylation patterns, we constructed chimeric MERS-CoV virus-like particles (VLPs) and determined their immunogenicity and protective efficacy in mice. RESULTS: Western blot and cryo-electron microscopy analyses demonstrated that MERS-CoV VLPs were efficiently produced in cells co-transfected with MERS-CoV spike (S), envelope, membrane and murine hepatitis virus nucleocapsid genes. We examined their ability as a vaccine in a human dipeptidyl peptidase 4 knock-in C57BL/6 congenic mouse model. Mice immunized with MERS VLPs produced S-specific antibodies with virus neutralization activity. Furthermore, MERS-CoV VLP immunization provided complete protection against a lethal challenge with mouse-adapted MERS-CoV and improved virus clearance in the lung. CONCLUSIONS: Overall, these data demonstrate that MERS-CoV VLPs have excellent immunogenicity and represent a promising vaccine candidate.


Subject(s)
Coronavirus Infections , Middle East Respiratory Syndrome Coronavirus , Vaccines, Virus-Like Particle , Viral Vaccines , Animals , Antibodies, Neutralizing , Antibodies, Viral , Cryoelectron Microscopy , Mammals , Mice , Mice, Inbred C57BL , Middle East Respiratory Syndrome Coronavirus/genetics , Spike Glycoprotein, Coronavirus/genetics , Vaccines, Virus-Like Particle/genetics , Viral Vaccines/genetics
16.
IEEE Pulse ; 13(3): 19-22, 2022.
Article in English | MEDLINE | ID: covidwho-1901485

ABSTRACT

While COVID-19 Has been racing through much of the human population, the SARS-CoV-2 virus has also turned up in other mammals. This leads to many questions: Might these animals serve as reservoirs where new variants can emerge and then infect humans? Can animal surveillance identify novel variants before they appear in humans? How dangerous is COVID-19 to nonhuman animals?


Subject(s)
COVID-19 , Animals , Fear , Humans , Mammals , SARS-CoV-2
17.
Cells ; 11(12)2022 06 17.
Article in English | MEDLINE | ID: covidwho-1896812

ABSTRACT

Platelets are among the most abundant cells in the mammalian circulation. Classical platelet functions in hemostasis and wound healing have been intensively explored and are generally accepted. During the past decades, the research focus broadened towards their participation in immune-modulatory events, including pro-inflammatory and, more recently, inflammatory resolution processes. Platelets are equipped with a variety of abilities enabling active participation in immunological processes. Toll-like receptors mediate the recognition of pathogens, while the release of granule contents and microvesicles promotes direct pathogen defense and an interaction with leukocytes. Platelets communicate and physically interact with neutrophils, monocytes and a subset of lymphocytes via soluble mediators and surface adhesion receptors. This interaction promotes leukocyte recruitment, migration and extravasation, as well as the initiation of effector functions, such as the release of extracellular traps by neutrophils. Platelet-derived prostaglandin E2, C-type lectin-like receptor 2 and transforming growth factor ß modulate inflammatory resolution processes by promoting the synthesis of pro-resolving mediators while reducing pro-inflammatory ones. Furthermore, platelets promote the differentiation of CD4+ T cells in T helper and regulatory T cells, which affects macrophage polarization. These abilities make platelets key players in inflammatory diseases such as pneumonia and the acute respiratory distress syndrome, including the pandemic coronavirus disease 2019. This review focuses on recent findings in platelet-mediated immunity during acute inflammation.


Subject(s)
Blood Platelets , COVID-19 , Animals , Blood Platelets/metabolism , Hemostasis , Inflammation/metabolism , Mammals , Neutrophils
18.
Sci Rep ; 12(1): 7010, 2022 04 29.
Article in English | MEDLINE | ID: covidwho-1890243

ABSTRACT

The worldwide COVID-19 pandemic caused by the SARS-CoV-2 betacoronavirus has highlighted the need for a synthetic biology approach to create reliable and scalable sources of viral antigen for uses in diagnostics, therapeutics and basic biomedical research. Here, we adapt plasmid-based systems in the eukaryotic microalgae Phaeodactylum tricornutum to develop an inducible overexpression system for SARS-CoV-2 proteins. Limiting phosphate and iron in growth media induced expression of the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein from the P. tricornutum HASP1 promoter in the wild-type strain and in a histidine auxotrophic strain that alleviates the requirement for antibiotic selection of expression plasmids. The RBD was purified from whole cell extracts (algae-RBD) with yield compromised by the finding that 90-95% of expressed RBD lacked the genetically encoded C-terminal 6X-histidine tag. Constructs that lacked the TEV protease site between the RBD and C-terminal 6X-histidine tag retained the tag, increasing yield. Purified algae-RBD was found to be N-linked glycosylated by treatment with endoglycosidases, was cross-reactive with anti-RBD polyclonal antibodies, and inhibited binding of recombinant RBD purified from mammalian cell lines to the human ACE2 receptor. We also show that the algae-RBD can be used in a lateral flow assay device to detect SARS-CoV-2 specific IgG antibodies from donor serum at sensitivity equivalent to assays performed with RBD made in mammalian cell lines. Our study shows that P. tricornutum is a scalable system with minimal biocontainment requirements for the inducible production of SARS-CoV-2 or other coronavirus antigens for pandemic diagnostics.


Subject(s)
COVID-19 , Diatoms , Animals , COVID-19/diagnosis , Diatoms/genetics , Diatoms/metabolism , Histidine , Humans , Mammals/metabolism , Membrane Glycoproteins/metabolism , Pandemics , Phosphates , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus , Viral Envelope Proteins/metabolism
19.
PLoS One ; 17(6): e0268251, 2022.
Article in English | MEDLINE | ID: covidwho-1887011

ABSTRACT

Multiepitope vaccines could induce multiantigenic immunity against large complex pathogens with different strain variants. Herein, the in silico, in vitro and in vivo studies were used to design and develop a novel candidate antigenic multiepitope vaccine against SARS-CoV-2 pathogen. The designed multiepitope construct targets the spike glycoprotein (S), membrane protein (M), and nucleocapsid phosphoprotein (N) of SARS-CoV-2 (i.e., the S-N-M construct). This construct contains the cytotoxic T lymphocyte (CTL)-, helper T lymphocyte (HTL)-, and linear B lymphocyte (LBL)-inducing epitopes. The multiepitope s-n-m fusion gene was subcloned in prokaryotic (pET24a) and eukaryotic (pcDNA3.1) expression vectors. Its expression was evaluated in mammalian cell line using LL37 cell penetrating peptide. Moreover, the recombinant multiepitope S-N-M peptide was produced in E. coli strain. Finally, mice were immunized using homologous and heterologous regimens for evaluation of immune responses. Our data indicated that the multiepitope S-N-M peptide construct combined with Montanide 720 in homologous regimen significantly stimulated total IgG, IgG2a, IFN-γ, TNF-α, IL-15, IL-21 and IL-6, and Granzyme B secretion as compared to other groups. Moreover, the pcDNA-s-n-m/ LL37 nanoparticles significantly induced higher immune responses than the naked DNA in both homologous and heterologous regimens. In general, our designed multiepitope vaccine construct can be considered as a vaccine candidate in SARS-CoV-2 infection model.


Subject(s)
COVID-19 , SARS-CoV-2 , Animals , COVID-19/prevention & control , COVID-19 Vaccines , Epitopes, B-Lymphocyte , Epitopes, T-Lymphocyte/genetics , Escherichia coli , Humans , Mammals , Mice , Mineral Oil , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , Vaccines, Subunit
20.
Vaccine ; 40(32): 4522-4530, 2022 Jul 30.
Article in English | MEDLINE | ID: covidwho-1886121

ABSTRACT

The COVID-19 pandemic has spurred an unprecedented movement to develop safe and effective vaccines against the SARS-CoV-2 virus to immunize the global population. The first set of vaccine candidates that received emergency use authorization targeted the spike (S) glycoprotein of the SARS-CoV-2 virus that enables virus entry into cells via the receptor binding domain (RBD). Recently, multiple variants of SARS-CoV-2 have emerged with mutations in S protein and the ability to evade neutralizing antibodies in vaccinated individuals. We have developed a dual RBD and nucleocapsid (N) subunit protein vaccine candidate named RelCoVax® through heterologous expression in mammalian cells (RBD) and E. coli (N). The RelCoVax® formulation containing a combination of aluminum hydroxide (alum) and a synthetic CpG oligonucleotide as adjuvants elicited high antibody titers against RBD and N proteins in mice after a prime and boost dose regimen administered 2 weeks apart. The vaccine also stimulated cellular immune responses with a potential Th1 bias as evidenced by increased IFN-γ release by splenocytes from immunized mice upon antigen exposure particularly N protein. Finally, the serum of mice immunized with RelCoVax® demonstrated the ability to neutralize two different SARS-CoV-2 viral strains in vitro including the Delta strain that has become dominant in many regions of the world and can evade vaccine induced neutralizing antibodies. These results warrant further evaluation of RelCoVax® through advanced studies and contribute towards enhancing our understanding of multicomponent subunit vaccine candidates against SARS-CoV-2.


Subject(s)
COVID-19 , SARS-CoV-2 , Animals , Antibodies, Neutralizing , Antibodies, Viral , COVID-19/prevention & control , COVID-19 Vaccines , Escherichia coli , Humans , Immunity, Cellular , Mammals , Mice , Pandemics , Spike Glycoprotein, Coronavirus/genetics , Vaccines, Subunit
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