Lactobacillus rhamnosus dampens cytokine and chemokine secretion from primary human nasal epithelial cells infected with rhinovirus.

AIMS: To investigate the effect of Lactobacillus rhamnosus on viral replication and cellular response to human rhinovirus (HRV) infection, including the secretion of antiviral and inflammatory mediators from well-differentiated nasal epithelial cells (WD-NECs). METHODS AND RESULTS: The WD-NECs from healthy adult donors (N = 6) were cultured in vitro, exposed to different strains of L. rhamnosus (D3189, D3160, or LB21), and infected with HRV (RV-A16) after 24 h. Survival and adherence capacity of L. rhamnosus in a NEC environment were confirmed using CFSE-labelled isolates, immunofluorescent staining, and confocal microscopy. Shed virus and viral replication were quantified using TCID50 assays and RT-qPCR, respectively. Cytotoxicity was measured by lactate dehydrogenase (LDH) activity. Pro-inflammatory mediators were measured by multiplex immunoassay, and interferon (IFN)-λ1/3 was measured using a standard ELISA kit. Lactobacillus rhamnosus was able to adhere to and colonize WD-NECs prior to the RV-A16 infection. Lactobacillus rhamnosus did not affect shed RV-A16, viral replication, RV-A16-induced IFN-λ1/3 production, or LDH release. Pre-exposure to L. rhamnosus, particularly D3189, reduced the secretion of RV-A16-induced pro-inflammatory mediators by WD-NECs. CONCLUSIONS: These findings demonstrate that L. rhamnosus differentially modulates RV-A16-induced innate inflammatory immune responses in primary NECs from healthy adults.

Ancestral SARS-CoV-2, but not Omicron, replicates less efficiently in primary pediatric nasal epithelial cells.

Children typically experience more mild symptoms of Coronavirus Disease 2019 (COVID-19) when compared to adults. There is a strong body of evidence that children are also less susceptible to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection with the ancestral viral isolate. However, the emergence of SARS-CoV-2 variants of concern (VOCs) has been associated with an increased number of pediatric infections. Whether this is the result of widespread adult vaccination or fundamental changes in the biology of SARS-CoV-2 remain to be determined. Here, we use primary nasal epithelial cells (NECs) from children and adults, differentiated at an air-liquid interface to show that the ancestral SARS-CoV-2 replicates to significantly lower titers in the NECs of children compared to those of adults. This was associated with a heightened antiviral response to SARS-CoV-2 in the NECs of children. Importantly, the Delta variant also replicated to significantly lower titers in the NECs of children. This trend was markedly less pronounced in the case of Omicron. It is also striking to note that, at least in terms of viral RNA, Omicron replicated better in pediatric NECs compared to both Delta and the ancestral virus. Taken together, these data show that the nasal epithelium of children supports lower infection and replication of ancestral SARS-CoV-2, although this may be changing as the virus evolves.

Targeting the P2Y13 Receptor Suppresses IL-33 and HMGB1 Release and Ameliorates Experimental Asthma.

Rationale: The alarmins IL-33 and HMGB1 (high mobility group box 1) contribute to type 2 inflammation and asthma pathogenesis. Objectives: To determine whether P2Y13-R (P2Y13 receptor), a purinergic GPCR (G protein-coupled receptor) and risk allele for asthma, regulates the release of IL-33 and HMGB1. Methods: Bronchial biopsy specimens were obtained from healthy subjects and subjects with asthma. Primary human airway epithelial cells (AECs), primary mouse AECs, or C57Bl/6 mice were inoculated with various aeroallergens or respiratory viruses, and the nuclear-to-cytoplasmic translocation and release of alarmins was measured by using immunohistochemistry and an ELISA. The role of P2Y13-R in AEC function and in the onset, progression, and exacerbation of experimental asthma was assessed by using pharmacological antagonists and mice with P2Y13-R gene deletion. Measurements and Main Results: Aeroallergen exposure induced the extracellular release of ADP and ATP, nucleotides that activate P2Y13-R. ATP, ADP, and aeroallergen (house dust mite, cockroach, or Alternaria antigen) or virus exposure induced the nuclear-to-cytoplasmic translocation and subsequent release of IL-33 and HMGB1, and this response was ablated by genetic deletion or pharmacological antagonism of P2Y13. In mice, prophylactic or therapeutic P2Y13-R blockade attenuated asthma onset and, critically, ablated the severity of a rhinovirus-associated exacerbation in a high-fidelity experimental model of chronic asthma. Moreover, P2Y13-R antagonism derepressed antiviral immunity, increasing IFN-λ production and decreasing viral copies in the lung. Conclusions: We identify P2Y13-R as a novel gatekeeper of the nuclear alarmins IL-33 and HMGB1 and demonstrate that the targeting of this GPCR via genetic deletion or treatment with a small-molecule antagonist protects against the onset and exacerbations of experimental asthma.

Plaque Longitudinal Heterogeneity in Morphology, Property, and Mechanobiology.

BACKGROUND AND PURPOSE: The hemodynamic environment of an atherosclerotic plaque varies along the longitudinal direction. Investigating the changes in plaque morphology and its biomechanical environment along the longitudinal direction and their correlations will enhance our understanding of plaque progression and arterial remodeling. METHODS: Six male patients with carotid stenosis >70% were recruited. Multisequence high-resolution MRI was performed at the carotid bifurcation. Carotid endarterectomy was performed following MRI, and the plaque tissue was collected for histological and mechanical testing. Patient-specific biomechanical modeling and simulations were conducted to calculate the mechanical stresses (wall shear stress [WSS] and von Mises stress [VMS]). Changes in plaque cross-sectional morphology, WSS, and VMS as well as their correlations were evaluated. RESULTS: Positive correlations were found between % stenosis and % inflammation (MA) (p = 0.019), % lipid area and % MA (p = 0.026), and % calcification area and VMS (p = 0.007). Negative correlations were found between VMS and % stenosis (p = 0.028) and VMS and average WSS (p = 0.034). Moreover, the peak stresses and neovessels were found to be in the shoulder regions. High-stress concentrations were found in the interface regions of the calcification and surrounding tissue, thereby increasing plaque vulnerability. CONCLUSIONS: Correlations between the morphology and stresses suggest that arterial remodeling is a dynamic interaction between mechanical environment and plaque progression resulting in plaque heterogeneity. Our finding indicates that plaque heterogeneity is associated with plaque progression and can be combined with mechanical stresses for identifying high-risk plaques.

Antiviral and Antibacterial Nanostructured Surfaces with Excellent Mechanical Properties for Hospital Applications.

With the rise of bacterial and viral infections including the recent outbreak of coronavirus, the requirement for novel antimicrobial strategies is also rising with urgency. To solve this problem, we have used a wet etching technique to fabricate 23 nm wide nanostructures randomly aligned as ridges on aluminum (Al) 6063 alloy surfaces. The surfaces were etched for 0.5, 1, and 3 h. The surfaces were characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy, contact angle goniometry, nanoindentation and atomic force microscopy. Strains of the Gram negative bacteria Pseudomonas aeruginosa and the Gram positive bacteria Staphylococcus aureus were used to evaluate the bacterial attachment behavior. For the first time, common respiratory viruses, respiratory syncytial virus (RSV) and rhinovirus (RV), were investigated for antiviral activity on nanostructured surfaces. It was found that the etched Al surfaces were hydrophilic and the nanoscale roughness enhanced with the etching time with Rrms ranging from 69.9 to 995 nm. Both bacterial cells of P. aeruginosa and S. aureus were physically deformed and were nonviable upon attachment after 3 h on the etched Al 6063 surface. This nanoscale surface topography inactivated 92 and 87% of the attached P. aeruginosa and S. aureus cells, respectively. The recovery of infectious RSV was also reduced significantly within 2 h of exposure to the nanostructured surfaces compared to the smooth Al control surfaces. There was a 3-4 log10 reduction in the viability counts of rhinovirus after 24 h on the nanostructured surfaces. The nanostructured surfaces exhibited excellent durability as the surfaces sustained 1000 cycles of 2000 µN load without any damage. This is the first report that has shown the combined antibacterial and antiviral property of the nanostructured surface with excellent nanomechanical properties that could be potentially significant for use in hospital environments to stop the spread of infections arising from physical surfaces.

Antiviral Nanostructured Surfaces Reduce the Viability of SARS-CoV-2.

In this letter, we report the ability of the nanostructured aluminum Al 6063 alloy surfaces to inactivate the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). There was no recoverable viable virus after 6 h of exposure to the nanostructured surface, elucidating a 5-log reduction compared to a flat Al 6063 surface. The nanostructured surfaces were fabricated using wet-etching techniques which generated nanotextured, randomly aligned ridges approximately 23 nm wide on the Al 6063 alloy surfaces. In addition to the excellent mechanical resilience properties previously shown, the etched surfaces have also demonstrated superior corrosion resistance compared to the control surfaces. Such nanostructured surfaces have the potential to be used in healthcare environment such as hospitals and public spaces to reduce the surface transmission of SARS-CoV-2 and combat COVID-19.

Bacterial adherence and biofilm formation on medical implants: a review.

Biofilms are a complex group of microbial cells that adhere to the exopolysaccharide matrix present on the surface of medical devices. Biofilm-associated infections in the medical devices pose a serious problem to the public health and adversely affect the function of the device. Medical implants used in oral and orthopedic surgery are fabricated using alloys such as stainless steel and titanium. The biological behavior, such as osseointegration and its antibacterial activity, essentially depends on both the chemical composition and the morphology of the surface of the device. Surface treatment of medical implants by various physical and chemical techniques are attempted in order to improve their surface properties so as to facilitate bio-integration and prevent bacterial adhesion. The potential source of infection of the surrounding tissue and antimicrobial strategies are from bacteria adherent to or in a biofilm on the implant which should prevent both biofilm formation and tissue colonization. This article provides an overview of bacterial biofilm formation and methods adopted for the inhibition of bacterial adhesion on medical implants.