Self-assembling short immunostimulatory duplex RNAs with broad spectrum antiviral activity

The current COVID-19 pandemic highlights the need for broad-spectrum antiviral therapeutics. Here we describe a new class of self-assembling immunostimulatory short duplex RNAs that potently induce production of type I and type III interferon (IFN-I and IFN-III), in a wide range of human cell types. These RNAs require a minimum of 20 base pairs, lack any sequence or structural characteristics of known immunostimulatory RNAs, and instead require a unique conserved sequence motif (sense strand: 5-C, antisense strand: 3-GGG) that mediates end-to-end dimer self-assembly of these RNAs by Hoogsteen G-G base-pairing. The presence of terminal hydroxyl or monophosphate groups, blunt or overhanging ends, or terminal RNA or DNA bases did not affect their ability to induce IFN. Unlike previously described immunostimulatory siRNAs, their activity is independent of TLR7/8, but requires the RIG-I/IRF3 pathway that induces a more restricted antiviral response with a lower proinflammatory signature compared with poly(I:C). Immune stimulation mediated by these duplex RNAs results in broad spectrum inhibition of infections by many respiratory viruses with pandemic potential, including SARS-CoV-2, SARS-CoV, MERS-CoV, and influenza A, as well as the common cold virus HCoV-NL63 in both cell lines and human Lung Chips that mimic organ-level lung pathophysiology. These short dsRNAs can be manufactured easily, and thus potentially could be harnessed to produce broad-spectrum antiviral therapeutics at low cost.

Mechanical control of innate immune responses against viral infection revealed in a human Lung Alveolus Chip

Mechanical forces associated with breathing play a fundamental role in lung development and disease but the molecular pathways remain largely unknown. Here, we used a mechanically actuatable Human Lung Alveolus Chip that recapitulates human lung alveolar type I and type II cell differentiation, alveolar-capillary interface formation, and genome-wide gene expression profiles characteristic of the distal lung to investigate the role of physical forces associated with cyclic breathing motions in lung innate immune responses to viral infection. When the mechanically active Alveolus Chips are infected with the influenza H3N2 virus, a cascade of host responses is elicited on-chip, including increased production of cytokines and expression of inflammation-associated genes in pulmonary epithelial and endothelial cells, resulting in enhanced recruitment of circulating immune cells as occurs during viral infection in vivo. Surprisingly, studies carried out in parallel with static chips revealed that physiological breathing motions suppress viral replication by activating protective innate immune responses in epithelial and endothelial cells. This is mediated at least in part through upregulation of S100 calcium-binding protein A7 (S100A7), which binds to the Receptor for Advanced Glycation End Products (RAGE), an inflammatory mediator that is most highly expressed in the lung alveolus in vivo. This mechano-immunological control mechanism is further supported by the finding that existing RAGE inhibitor drugs can suppress the production of inflammatory cytokines in response to influenza virus infection in this model. S100A7-RAGE interactions and modulation of mechanical ventilation parameters could therefore serve as new targets for therapeutic intervention in patients infected with influenza and other potential pandemic viruses that cause life-threatening lung inflammation.

Human organs-on-chips as tools for repurposing approved drugs as potential influenza and COVID19 therapeutics in viral pandemics

The rising threat of pandemic viruses, such as SARS-CoV-2, requires development of new preclinical discovery platforms that can more rapidly identify therapeutics that are active in vitro and also translate in vivo. Here we show that human organ-on-a-chip (Organ Chip) microfluidic culture devices lined by highly differentiated human primary lung airway epithelium and endothelium can be used to model virus entry, replication, strain-dependent virulence, host cytokine production, and recruitment of circulating immune cells in response to infection by respiratory viruses with great pandemic potential. We provide a first demonstration of drug repurposing by using oseltamivir in influenza A virus-infected organ chip cultures and show that co-administration of the approved anticoagulant drug, nafamostat, can double oseltamivirs therapeutic time window. With the emergence of the COVID-19 pandemic, the Airway Chips were used to assess the inhibitory activities of approved drugs that showed inhibition in traditional cell culture assays only to find that most failed when tested in the Organ Chip platform. When administered in human Airway Chips under flow at a clinically relevant dose, one drug - amodiaquine - significantly inhibited infection by a pseudotyped SARS-CoV-2 virus. Proof of concept was provided by showing that amodiaquine and its active metabolite (desethylamodiaquine) also significantly reduce viral load in both direct infection and animal-to-animal transmission models of native SARS-CoV-2 infection in hamsters. These data highlight the value of Organ Chip technology as a more stringent and physiologically relevant platform for drug repurposing, and suggest that amodiaquine should be considered for future clinical testing.

Expression and protective effect of induced heat shock protein 70 in retinal neurons and M?ller cells / 中华眼底病杂志

Objective To investigate the expression of induced heat shock protein (HSP) 70 in rat′s retinal neurons (RNs) and M?ller cells, and evaluate the protective effect of HSP 70 on RNs injured with glucose deprivation and glutamate. Methods Rat′s RNs and M?ller cells cultured in vitro were treated with heat shock (42℃ for 1 hour), and duration of the expression of HSP70 was detected by immunocytochemical techniques. Viability of the cells was measured by methyl thiazolyl tetrazolium (MTT) chromatometry after incitant toxic injury with glucose deprivation (0.56 mmol/L glucose for 6 hours) and glutamate (100 ?mol/L for 6 hours). Simultaneously, the expression was interdicted by HSP70. Results Hypereffective expression of HSP70 was found in cultured RNs and M?ller cells after heat shock. The viability of RNs pretreated by heat shock after injured with glucose deprivation and glutamate significantly increased which could be interdicted by HSP70 antibody. Conclusion Hypereffective expression of HSP 70 may be induced by heat shock, which enhances the ability of tolerance of RNs to the incitant toxic injury by glucose deprivation and exitotoxicity.

Comparative study on analysis of retinal thickness at posterior pole in primary and suspected glaucoma / 中华眼底病杂志

Objective To determine the difference of global indices of retinal thickness at posterior pole in primary and suspected glaucoma. Methods Forty five global indices of analysis on retinal thickness at posterior pole in every case, including 12 cases of primary open angle glaucoma and 11 cases of suspected glaucoma were obtained by advanced retinal thickness analyzer. Every index was also compared. Results There were significant differences between primary and suspected glaucoma in foveal shape deviation (FSD), foveal corrected thickness deviation (FCTD), foveal fixation corrected thickness deviation (FFD), foveola thickness deviation (VTD), corrected foveola thickness deviation (CVTD), peri foveal abnormally thin area (PFATN), posterior pole pattern deviation (PPPD), and posterior pole abnormally thin area (PPATN). Conclusion There are significant difference of morphologic indices of retinal thickness at posterior pole between primary and suspected glaucoma.

Expression of inducible nitric oxide (NO) synthase and arginine-metabolic relative enzymes in retinal pigment epithelial (RPE) cells and the effect of NO on tight junction of RPE cells / 中华眼底病杂志

Objective To detect the induction of inducible nitric oxide synthase (iNOS) and nitric oxide (NO) production in immunostimulated retinal pigment epithelial (RPE) cells to seek for the supplying of the arginine, a substrate for NOS; as well as the effects of produced NO on the tight junction of RPE-J cells. Methods Rat′s RPE-J cells were treated with interferon-?(INF-?), tumor necrosis factor-?(TNF-?) and lipopolysaccharide (LPS), and Northern and Western blotting were applied to analyze the expression of the citrulline-NO cycle enzymes and related enzymes and the effect of dexamethasone and cyclic adenosine monophosphate (camp) on the expression of iNOS. Immunocytochemistry reaction and Western blotting were used to evaluate the effect of produced NO on the tight junctions of RPE-J cells. Results iNOS and argininosuccinate synthetase (AS) were highly induced at both mRNA and protection levels in immunostimulated RPE cells while arginiosuccinate lyase (AL) was not induced. NO was produced by cells after stimulation with TNF?, IFN? and LPS. The induction of iNOS mRNA and the production of NO by these immunostimulated cells was further enhanced by cAMP. NO was produced from citrulline as well as from arginine. And the produced NO impaired the tight junction of RPE-J cells, decreased the production of tight junction related protein ZO-1. Conclusion In activated RPE-J cells, citrulline-arginine recycling is important for NO production, and the produced NO weakened the function of tight junction of RPE-J cells.