Identification of a suitable nonhuman primate (NHP) model of COVID-19 remains challenging. Here, we characterized severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in three NHP species: Old World monkeys Macaca mulatta (M. mulatta) and Macaca fascicularis (M. fascicularis) and New World monkey Callithrix jacchus (C. jacchus). Infected M. mulatta and M. fascicularis showed abnormal chest radiographs, an increased body temperature and a decreased body weight. Viral genomes were detected in swab and blood samples from all animals. Viral load was detected in the pulmonary tissues of M. mulatta and M. fascicularis but not C. jacchus. Furthermore, among the three animal species, M. mulatta showed the strongest response to SARS-CoV-2, including increased inflammatory cytokine expression and pathological changes in the pulmonary tissues. Collectively, these data revealed the different susceptibilities of Old World and New World monkeys to SARS-CoV-2 and identified M. mulatta as the most suitable for modeling COVID-19.
COVID-19, caused by SARS-CoV-2 infection, has recently been announced as a pandemic all over the world. Plenty of diagnostic, preventive and therapeutic knowledges have been enriched from clinical studies since December 2019. However, animal models, particularly non-human primate models, are urgently needed for critical questions that could not be answered in clinical patients, evaluations of anti-viral drugs and vaccines. In this study, two families of non-human primates, old world monkeys (12 Macaca mulatta, 6 Macaca fascicularis) and new world monkeys (6 Callithrix jacchus), were experimentally inoculated with SARS-CoV-2. Clinical signs were recorded. Samples were collected for analysis of viral shedding, viremia and histopathological examination. Increased body temperature was observed in 100% (12/12) M. mulatta, 33.3% (2/6) M. fascicularis and none (0/6) of C. jacchus post inoculation of SARS-CoV-2. All of M. mulatta and M. fascicularis showed chest radiographic abnormality. Viral genomes were detected in nasal swabs, throat swabs, anal swabs and blood from all 3 species of monkeys. Viral shedding from upper respiratory reached the peak between day 6 and day 8 post inoculation. From necropsied M. mulatta and M. fascicularis, tissues showing virus positive were mainly lung, weasand, bronchus and spleen. No viral genome was seen in any of tissues from 2 necropsied C.jacchus. Severe gross lesions and histopathological changes were observed in lung, heart and stomach of SARS-CoV-2 infected animals. In summary, we have established a NHP model for COVID-19, which could be used to evaluate drugs and vaccines, and investigate viral pathogenesis. M. mulatta is the most susceptible to SARS-CoV2 infection, followed by M. fascicularis and C. jacchus. One Sentence Summary:M. mulatta is the most susceptible to SARS-CoV-2 infection as compared to M. fascicularis and C. jacchus.
[1] In June 1999, an intense swarm of earthquakes occurred on the Endeavour segment of the Juan de Fuca Ridge influencing hydrothermal activity in and around the Main Endeavour Field (MEF). Here we report the dissolved concentrations of 31 species from five high-temperature vents sampled 3 months after the seismic event. The spatial variability of vent fluid chemistry is extreme. Vapor-dominated vent fluids at Cantilever and Sully sites have high measured temperatures (375°-379°C), high dissolved gas and boron concentrations, but low SiO 2 . Modeling results indicate that these fluids can be accounted for by supercritical phase separation and brine condensation. Other vent fluids have moderate temperatures (340°-366°C) and chloride concentrations (208-426 mmol/kg), and may result from mixing of supercritical, vapor-rich fluids with evolved seawater. Phase equilibria calculations indicate that in addition to chloride, redox, temperature, and especially pressure play key roles in accounting for compositional variability of vent fluids at MEF. In comparison with earlier (1988) data, the 1999 data set reveals significantly lower chloride concentrations and higher boron, whereas alkali and alkaline earth cations are lower by 10-20% in keeping with chloride decrease. That dissolved chloride, boron, and other elements returned to preevent levels when again sampled in 2000 provide additional data documenting the inherently dynamic nature of hydrothermal systems at mid-ocean ridges.
Polyamines (putrescine, spermidine, and spermine) are essential for growth and survival of all cells. When polyamine biosynthesis is inhibited, there is up-regulation of import. The mammalian polyamine transport system is unknown. We have previously shown that the heparan sulfate (HS) side chains of recycling glypican-1 (Gpc-1) can sequester spermine, that intracellular polyamine depletion increases the number of NO-sensitive N-unsubstituted glucosamines in HS, and that NO-dependent cleavage of HS at these sites is required for spermine uptake. The NO is derived from S-nitroso groups in the Gpc-1 protein. Using RNA interference technology as well as biochemical and microscopic techniques applied to both normal and uptake-deficient cells, we demonstrate that inhibition of Gpc-1 expression abrogates spermine uptake and intracellular delivery. In unperturbed cells, spermine and recycling Gpc-1 carrying HS chains rich in Nunsubstituted glucosamines were co-localized. By exposing cells to ascorbate, we induced release of NO from the S-nitroso groups, resulting in HS degradation and unloading of the sequestered polyamines as well as nuclear targeting of the deglycanated Gpc-1 protein. Polyamine uptake-deficient cells appear to have a defect in the NO release mechanism. We have managed to restore spermine uptake partially in these cells by providing spermine NONOate and ascorbate. The former bound to the HS chains of recycling Gpc-1 and S-nitrosylated the core protein. Ascorbate released NO, which degraded HS and liberated the bound spermine. Recycling HS proteoglycans of the glypican-type may be plasma membrane carriers for cargo taken up by caveolar endocytosis.
Background and Aims Gastrointestinal (GI) manifestations have been increasingly reported in Coronavirus Disease 2019 (COVID-19) patients. However, the roles of the GI tract in severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection are not fully understood. We investigated how the GI tract is involved in SARS-CoV-2 infection to elucidate the pathogenesis of COVID-19. Methods Our previously established nonhuman primate (NHP) model of COVID-19 was modified in this study to test our hypothesis. Rhesus monkeys were infected with an intragastric or intranasal challenge with SARS-CoV-2. Clinical signs were recorded after infection. Viral genomic RNA was quantified by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Host responses to SARS-CoV-2 infection were evaluated by examining inflammatory cytokines, macrophages, histopathology and mucin barrier integrity. Results Intranasal inoculation with SARS-CoV-2 led to infections and pathological changes not only in respiratory tissues but also in digestive tissues. Expectedly, intragastric inoculation with SARS-CoV-2 resulted in the productive infection of digestive tissues and inflammation in both the lung and digestive tissues. Inflammatory cytokines were induced by both types of inoculation with SARS-CoV-2, consistent with the increased expression of CD68. Immunohistochemistry and alcian blue/periodic acid-Schiff (AB-PAS) staining showed decreased Ki67, increased cleaved caspase 3 and decreased numbers of mucin-containing goblet cells, suggesting that the inflammation induced by these two types of inoculation with SARS-CoV-2 impaired the GI barrier and caused severe infections. Conclusions Both intranasal and intragastric inoculation with SARS-CoV-2 caused pneumonia and GI dysfunction in our rhesus monkey model. Inflammatory cytokines are possible connections for the pathogenesis of SARS-CoV-2 between the respiratory and digestive systems.
However, such residues were scarce in cell surface glypican-1. Brefeldin A-arrested glypican-1, which was non-S-nitrosylated and carried side chains rich in Nunsubstituted glucosamines, colocalized extensively with caveolin-1 but not with Rab9. Suramin, which inhibits heparanase, induced the appearance of Snitrosylated glypican-1 in caveolin-1-rich compartments. Inhibition of deaminative cleavage did not prevent heparanase from generating heparan sulfate oligosaccharides that colocalized strongly with caveolin-1. Growthquiescent cells displayed extensive NO-dependent deaminative cleavage of heparan sulfate-generating anhydromannose-terminating fragments that were partly associated with acidic vesicles. Proliferating cells generated such fragments during polyamine uptake. We conclude that recycling glypican-1 that is associated with caveolin-1-containing endosomes undergoes sequential N-desulfation/N-deacetylation, heparanase cleavage, S-nitrosylation, NO release, and deaminative cleavage of its side chains in conjunction with polyamine uptake.Mammalian glypican-1 (Gpc-1) 1 is a member of a glycosylphosphatidylinositol (GPI)-linked cell-surface proteoglycan (PG) family with six known members to date. These PG, like other cell surface PG, are selective regulators of ligand-receptor encounters and thereby control growth and development (1-4). Gpc proteins are post-translationally modified by the addition of the glycosaminoglycan heparan sulfate (HS) at sites located close to the C-terminal GPI-membrane anchor (see Scheme 1). The central part of the protein consists of a cysteine-rich domain containing information that ensures a high level of HS substitution (5). Many of the functions of Gpc are dependent on the HS side chains, which are capable of binding and/or activating and/or transporting a variety of growth factors, cytokines, enzymes, viral proteins, and polyamines (6 -11).GPI-anchored proteins are usually associated with sphingolipid-and cholesterol-rich plasma membrane domains. Such enriched domains may exist either as small phase-separated "rafts" or, when associated with caveolin-1 (Cav-1), form flaskshaped plasmalemmal invaginations called caveolae, which are involved in signal transduction and special forms of non-clathrindependent endocytosis mediated by Cav-1-containing endosomes, also called caveosomes (12)(13)(14)(15)(16)(17).Biochemical studies using radioactively labeled precursors have demonstrated recycling of newly made Gpc-1 in normal fibroblasts as well as in transformed cells (18,19). During recycling, the HS side chains are degraded both by heparanase and by NO-dependent deaminative cleavage at N-unsubstituted glucosamine residues (GlcNH 3 ϩ ) (20). New HS chains can then be synthesized on the stubs remaining on the core protein (see Scheme 1). Biosynthesis of HS takes place in the Golgi and involves many interacting enzymes (21,22). The stubs should first be extended with a GlcNAc-hexuronic acid (HexUA) repeat backbone. The GlcNH 3 ϩ residues are either a result of inadequate sulfation dur...
The cell surface heparan sulfate proteoglycan (HSPG) glypican-1 is up-regulated by pancreatic and breast cancer cells, and its removal renders such cells insensitive to many growth factors. We sought to explain why the cell surface HSPG syndecan-1, which is also up-regulated by these cells and is a known growth factor coreceptor, does not compensate for glypican-1 loss. We show that the initial responses of these cells to the growth factor FGF2 are not glypican dependent, but they become so over time as FGF2 induces shedding of syndecan-1. Manipulations that retain syndecan-1 on the cell surface make long-term FGF2 responses glypican independent, whereas those that trigger syndecan-1 shedding make initial FGF2 responses glypican dependent. We further show that syndecan-1 shedding is mediated by matrix metalloproteinase-7 (MMP7), which, being anchored to cells by HSPGs, also causes its own release in a complex with syndecan-1 ectodomains. These results support a specific role for shed syndecan-1 or MMP7–syndecan-1 complexes in tumor progression and add to accumulating evidence that syndecans and glypicans have nonequivalent functions in vivo.
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