Age-related rhesus macaque models of COVID-19

Background:Since December 2019,an outbreak of the Corona Virus disease 2019(COVID-19)caused by severe acute respiratory syndrome coronavirus(SARS-CoV-2)in Wuhan,China,has become a public health emergency of international concern.The high fatality of aged cases caused by SARS-CoV-2 was a need to explore the possible age-related phenomena with non-human primate models.Methods:Three 3-5 years old and two 15 years old rhesus macaques were intratracheally infected with SARS-CoV-2,and then analyzed by clinical signs,viral replication,chest X-ray,histopathological changes and immune response.Results:Viral replication of nasopharyngeal swabs,anal swabs and lung in old monkeys was more active than that in young monkeys for 14 days after SARS-CoV-2 challenge.Monkeys developed typical interstitial pneumonia characterized by thickened alveolar septum accompanied with inflammation and edema,notably,old monkeys exhibited diffuse severe interstitial pneumonia.Viral antigens were detected mainly in alveolar epithelial cells and macrophages.Conclusion:SARS-CoV-2 caused more severe interstitial pneumonia in old monkeys than that in young monkeys.Rhesus macaque models infected with SARS-CoV-2 provided insight into the pathogenic mechanism and facilitated the development of vaccines and therapeutics against SARS-CoV-2 infection.

Microarray microRNA profiling of urinary exosomes in a 5XFAD mouse model of Alzheimer’s disease

Background:Alzheimer's disease(AD)is an incurable and irreversible neurodegen-erative disease,without a clear pathogenesis.Therefore,identification of candidates before amyloid-βplaque(Aβ)deposition proceeds is of major significance for earlier intervention in AD.Methods:To explore the potential noninvasive earlier biomarkers of AD in a 5XFAD mouse model,microRNAs(miRNAs)from urinary exosomes in 1-month-old pre-Aβaccumulation 5XFAD mice models and their littermate controls were profiled by mi-croarray analysis.The differentially expressed miRNAs were further analyzed via droplet digital PCR(ddPCR).Results:Microarray analysis demonstrated that 48 differentially expressed miRNAs(18 upregulated and 30 downregulated),of which six miRNAs-miR-196b-5p,miR-339-3p,miR-34a-5p,miR-376b-3p,miR-677-5p,and miR-721-were predicted to display gene targets and important signaling pathways closely associated with AD pathogenesis and verified by ddPCR.Conclusions:Urinary exosomal miRNAs showing differences in expression prior to Aβ-plaque deposition were identified.These exosomal miRNAs represent potential noninvasive biomarkers that may be used to prevent AD in clinical applications.

SARS-CoV-2 infection aggravates chronic comorbidities of cardiovascular diseases and diabetes in mice

Background:Cardiovascular diseases(CVDs)and diabetes mellitus(DM)are top two chronic comorbidities that increase the severity and mortality of COVID-19.However,how SARS-CoV-2 alters the progression of chronic diseases remain unclear.Methods:We used adenovirus to deliver h-ACE2 to lung to enable SARS-CoV-2 infection in mice.SARS-CoV-2’s impacts on pathogenesis of chronic diseases were studied through histopathological,virologic and molecular biology analysis.Results:Pre-existing CVDs resulted in viral invasion,ROS elevation and activation of apoptosis pathways contribute myocardial injury during SARS-CoV-2 infection.Viral infection increased fasting blood glucose and reduced insulin response in DM model.Bone mineral density decreased shortly after infection,which associated with impaired PI3K/AKT/mTOR signaling.Conclusion:We established mouse models mimicked the complex pathological symptoms of COVID-19 patients with chronic diseases.Pre-existing diseases could impair the inflammatory responses to SARS-CoV-2 infection,which further aggravated the pre-existing diseases.This work provided valuable information to better understand the interplay between the primary diseases and SARS-CoV-2 infection.

Sequential infection with H1N1 and SARS-CoV-2 aggravated COVID-19 pathogenesis in a mammalian model, and covaccination as an effective method of prevention of COVID-19 and influenza

Influenza A virus may circulate simultaneously with the SARS-CoV-2 virus,leading to more serious respiratory diseases during this winter.However,the influence of these viruses on disease outcome when both influenza A and SARS-CoV-2 are present in the host remains unclear.Using a mammalian model,sequential infection was performed in ferrets and in K18-MCE2 mice,with SARS-CoV-2 infection following H1N1.We found that co-infection with H1N1 and SARS-CoV-2 extended the duration of clinical manifestation of COVID-19,and enhanced pulmonary damage,but reduced viral shedding of throat swabs and viral loads in the lungs of ferrets.Moreover,mortality was increased in sequentially infected mice compared with single-infection mice.Compared with singlevaccine inoculation,co-inoculation of PiCoVacc(a SARS-CoV-2 vaccine)and the flu vaccine showed no significant differences in neutralizing antibody titers or virus-specific immune responses.Combined immunization effectively protected K18-MCE2 mice against both H1N1 and SARS-CoV-2 infection.Our findings indicated the development of systematic models of co-infection of H1N1 and SARS-CoV-2,which together notably enhanced pneumonia in ferrets and mice,as well as demonstrated that simultaneous vaccination against HINT and SARS-CoV-2 may be an effective prevention strategy for the coming winter.

Differential transcriptomic landscapes of multiple organs from SARS-CoV-2 early infected rhesus macaques

SARS-CoV-2 infection causes complicated clinical manifestations with variable multi-organ injuries,how-ever,the underlying mechanism,in particular immune responses in different organs,remains elusive.In this study,comprehensive transcriptomic alterations of 14 tissues from rhesus macaque infected with SARS-CoV-2 were analyzed.Compared to normal controls,SARS-CoV-2 infection resulted in dysregulation of genes involving diverse functions in various examined tissues/organs,with drastic transcriptomic changes in cerebral cortex and right ventricle.Intriguingly,cerebral cortex exhibited a hyperinflammatory state evidenced by sig-nificant upregulation of inflammation response-related genes.Meanwhile,expressions of coagulation,angio-genesis and fibrosis factors were also up-regulated in cerebral cortex.Based on our findings,neuropilin 1(NRP1),a receptor of SARS-CoV-2,was significantly elevated in cerebral cortex post infection,accompanied by active immune response releasing inflammatory factors and signal transmission among tissues,which enhanced infection of the central nervous system(CNS)in a positive feedback way,leading to viral encephalitis.Overall,our study depicts a multi-tissue/organ tran-scriptomic landscapes of rhesus macaque with early infection of SARS-CoV-2,and provides important insights into the mechanistic basis for COVID-19-asso-ciated clinical complications.

SARS-CoV-2 treatment effects induced by ACE2-expressing microparticles are explained by the oxidized cholesterolincreased endosomal pH of alveolar macrophages

Exploring the cross-talk between the immune system and advanced biomaterials to treat SARS-CoV-2 infection is a promising strategy.Here,we show that ACE2-overexpressing A549 cell-derived microparticles(AO-MPs)are a potential therapeutic agent against SARS-CoV-2 infection.Intranasally administered AO-MPs dexterously navigate the anatomical and biological features of the lungs to enter the alveoli and are taken up by alveolar macrophages(AMs).Then,AO-MPs increase the endosomal pH but decrease the lysosomal pH in AMs,thus escorting bound SARS-CoV-2 from phago-endosomes to lysosomes for degradation.This pH regulation is attributable to oxidized cholesterol,which is enriched in AO-MPs and translocated to endosomal membranes,thus interfering with proton pumps and impairing endosomal acidification.In addition to promoting viral degradation,AO-MPs also inhibit the proinflammatory phenotype of AMs,leading to increased treatment efficacy in a SARS-CoV-2-infected mouse model without side effects.These findings highlight the potential use of AO-MPs to treat SARS-CoV-2-infected patients and showcase the feasibility of MP therapies for combatting emerging respiratory viruses in the future.