Respiratory Epithelium Research Articles

Nanoparticle-Mediated Mucosal Vaccination: Harnessing Nucleic Acids for Immune Enhancement.

Recent advancements in in vitro transcribed mRNA (IVT-mRNA) vaccine manufacturing have attracted considerable interest as advanced methods for combating viral infections. The respiratory mucosa is a primary target for pathogen attack, but traditional intramuscular vaccines are not effective in generating protective ion mucosal surfaces. Mucosal immunization can induce both systemic and mucosal immunity by effectively eliminating microorganisms before their growth and development. However, there are several biological and physical obstacles to the administration of genetic payloads, such as IVT-mRNA and DNA, to the pulmonary and nasal mucosa. Nucleic acid vaccine nanocarriers should effectively protect and load genetic payloads to overcome barriers i.e., biological and physical, at the mucosal sites. This may aid in the transfection of specific antigens, epithelial cells, and incorporation of adjuvants. In this review, we address strategies for delivering genetic payloads, such as nucleic acid vaccines, that have been studied in the past and their potential applications.

Nasal Epithelium Transcriptomics Predict Clinical Response to Elexacaftor/Tezacaftor/Ivacaftor.

Elexacaftor/tezacaftor/ivacaftor (ETI) has made a substantial positive impact for people living with CF (pwCF). However, there can be substantial variability in efficacy, and we lack adequate biomarkers to predict individual response. We thus aimed to identify transcriptomic profiles in nasal respiratory epithelium that predict clinical response to ETI treatment. We obtained nasal epithelial samples from pwCF prior to ETI initiation and performed a transcriptome-wide analysis of baseline gene expression to predict changes in FEV1 (∆FEV1), year's best FEV1 (∆ybFEV1), and body mass index (∆BMI). Using the top differentially expressed genes (DEGs), we generated transcriptomic risk scores (TRS) and evaluated their predictive performance. The study included 40 pwCF aged ≥6 years (mean 27.7 [SD=15.1] years; 40% female). After ETI initiation, FEV1 improved ≥5% in 22 (61.1%) participants and ybFEV1 improved ≥5% in 19 (50%). TRS were constructed using top over-expressed and under-expressed genes for each. Adding the ∆FEV1 TRS for to a model with age, sex, and baseline FEV1 increased the AUC from 0.41 to 0.88; the ∆ybFEV1 TRS increased the AUC from 0.51 to 0.88; and the ∆BMI TRS increased the AUC from 0.46 to 0.92. Average accuracy was thus ~85% in predicting the response to the three outcomes. Results were similar in models further adjusted for F508del zygosity and previous CFTR modulator use. In conclusion, we identified nasal epithelial transcriptomic profiles that help accurately predict changes in FEV1 and BMI with ETI treatment. These novel TRS could serve as predictive biomarkers for clinical response to modulator treatment in pwCF.

Upregulation of key factors of viral entry of corona- and influenza viruses upon TLR3-signaling in cells from the respiratory tract and clinical treatment options by 1,8-Cineol.

At the end of the 2019 coronavirus pandemic (COVID-19), highly contagious variants of coronaviruses had emerged. Together with influenza viruses, different variants of the coronavirus currently cause most colds and require appropriate drug treatment. We have investigated the expression of important factors for the replication of these viruses, namely transmembrane protease serine subtype 2 (TMPRSS2), neuropilin1 (NRP1), and angiotensin converting enzyme 2 (ACE2) or tumor necrosis factor-α (TNF-α) after toll like receptor-3 (TLR-3) stimulation using RT-qPCR and flow cytometry (FC) analysis. As model served primary fibroblasts derived from the lung and nasal cavity, as well as epidermal stem cells and fully matured respiratory epithelium. The stimulated cell cultures were treated with pharmaceuticals (Dexamethasone and Enzalutamide) and the outcome was compared with the phytomedicine 1,8-Cineol. The stimulation of TLR3 is sufficient to induce the expression of exactly those targets that were highly expressed in the corresponding culture type, specifically ACE2 and TMPRSS2 in respiratory epithelial stem cells and NRP1 in fibroblast cells. It seems this self-perpetuating cycle of infection-driven upregulation of key viral replication factors by the innate immune system represents an evolutionary advantage for viruses using these transcripts as viral replication factors. Likewise, to the standard pharmaceuticals with proven clinical efficiency, 1,8-Cineol was able to disrupt this self-perpetuating cycle. Considering the minor side effects and negligible pharmacological interactions with other drugs, it is conceivable that an adjuvant or combinatorial therapy with 1,8-Cineol for respiratory diseases caused by corona- or influenza viruses would be beneficial.

Development and characterization of an immortalized nasopharyngeal epithelial cell line to explore airway physiology and pathology in yak (Bos grunniens).

Airway epithelial cells play a crucial role in investigating the physiological and pathological mechanisms of the respiratory tract in yaks, a species whose unique respiratory system has garnered extensive interest. Despite this growing interest, there currently are no available airway epithelial cell lines from yaks, underscoring the crucial need to establish a yak respiratory epithelial cell line. Therefore, our objective was to isolate a population of primary yak nasopharyngeal epithelial cells (pYNE) and transform them into immortalized yak nasopharyngeal epithelial cells (iYNE), assessing their suitability as an in vitro model. Employing a combined method of physical elimination and differential adhesion, we successfully isolated a population of high-purity pYNE, and developed an iYNE line through pCI-neo-hTERT plasmid transfection. Karyotype and transmission electron microscopy analyses confirmed that pYNE and iYNE share identical morphologies and structures. Gel electrophoresis and real-time PCR analyses demonstrated that pYNE and iYNE expressed similar levels of KRT18 and CDH1 genes (p ≥ 0.541). Notably, iYNE expressed a significantly high level of TERT gene expression (p < 0.001). Immunofluorescence analysis demonstrated that both cell types expressed Pan-Cytokeratin, ZO-1, and E-cadherin proteins. Furthermore, immunoblotting analysis indicated significantly higher levels of hTERT and Ki67 proteins in iYNE (p < 0.001), and similar levels of Cluadin-3 and Occludin proteins (p ≥ 0.103). Proliferation curve analysis highlighted iYNE's serum-dependency and significantly enhanced proliferation capacities (p < 0.001). Additionally, pYNE and iYNE cells demonstrated comparable susceptibilities to infectious bovine rhinotracheitis virus (IBRV). These findings collectively suggest that the developed iYNE retains the evaluated physiological characteristics of pYNE, making it an appropriate in vitro model. This advancement will facilitate further investigation into the respiratory physiological and pathological mechanisms in yaks.

Virus-Mimetic Extracellular-Vesicle Vaccine Boosts Systemic and Mucosal Immunity via Immune Recruitment.

Mucosal vaccines can prevent viruses from infecting the respiratory mucosa, rather than only curtailing infection and protecting against the development of disease symptoms. The SARS-CoV-2 spike receptor-binding domain (RBD) is a compelling vaccine target but is undermined by suboptimal mucosal immunogenicity. Here, we report a SARS-CoV-2-mimetic extracellular-vesicle vaccine developed using genetic engineering and dendritic cell membrane budding. After mucosal immunization, the vaccine recruits antigen-presenting cells rapidly initiating a strong innate immune response. Notably, it obviates the need for adjuvants and can induce germinal center formation through both intramuscular and intratracheal vaccination. It not only elicits high levels of RBD-specific antibodies but also stimulates extensive cellular immunity in the respiratory mucosa. A sequential immunization strategy, starting with an intramuscular injection followed by an intratracheal booster, significantly bolsters mucosal immunity with high levels of IgA and tissue-resident memory T cell responses, thereby establishing a formidable defense against pseudovirus infection.

In vitro evaluation of using ceftazidime/avibactam against carbapenem-resistant Acinetobacter baumannii

ObjectiveCarbapenem-resistant Acinetobacter baumannii (CRAB) is a global concern as effective treatments are very limited. We previously used a modified susceptibility testing approach to predict growth suppression in carbapenem-resistant Enterobacterales, but there are uncertainties about the generalizability of the model. The objective of this study is to verify if a similar approach can be extended to CRAB. MethodA clinical isolate of CRAB resistant to ceftazidime/avibactam (CAZ/AVI, MIC = 32/4 mg/L) was examined. CAZ susceptibility was determined using increasing concentrations of AVI (0–64 mg/L), and MIC reduction was characterized with a sigmoid inhibitory maximum effect (Emax) model. The effectiveness of CAZ/AVI was validated in a hollow fibre infection model (HFIM) over 72 hours, using simulated unbound serum / epithelial lining fluid (ELF) exposures of 2.5 g over 2 hours every 8 hours. Baseline inocula of approximately 5.5 log CFU/mL were examined. ResultsAn AVI concentration-dependent reduction in CAZ MIC was observed (r2 = 0.99). CAZ MIC was dramatically reduced from 512 mg/L (no AVI) to 32 mg/L (AVI = 4 mg/L), and further to 8 mg/L (AVI = 16 mg/L). Pharmacokinetic simulations were satisfactory in the HFIM (r2 > 0.96). Bacterial suppression was observed >24 hours with the serum exposure, but not that from the ELF. ConclusionUsing multiple AVI concentrations within the clinically relevant range, our susceptibility testing approach could have better insights of treatment outcome for infections caused by CRAB. This could potentially lead to effective intervention(s) overlooked by conventional susceptibility testing method. This case highlights the importance of site-specific drug exposures on determining treatment outcome.

Fungal melanin suppresses airway epithelial chemokine secretion through blockade of calcium fluxing

Respiratory infections caused by the human fungal pathogen Aspergillus fumigatus are a major cause of mortality for immunocompromised patients. Exposure to these pathogens occurs through inhalation, although the role of the respiratory epithelium in disease pathogenesis has not been fully defined. Employing a primary human airway epithelial model, we demonstrate that fungal melanins potently block the post-translational secretion of the chemokines CXCL1 and CXCL8 independent of transcription or the requirement of melanin to be phagocytosed, leading to a significant reduction in neutrophil recruitment to the apical airway both in vitro and in vivo. Aspergillus-derived melanin, a major constituent of the fungal cell wall, dampened airway epithelial chemokine secretion in response to fungi, bacteria, and exogenous cytokines. Furthermore, melanin muted pathogen-mediated calcium fluxing and hindered actin filamentation. Taken together, our results reveal a critical role for melanin interaction with airway epithelium in shaping the host response to fungal and bacterial pathogens.

Cyclodextrin inclusion complex and amorphous solid dispersions as formulation approaches for enhancement of curcumin’s solubility and nasal epithelial membrane permeation

BackgroundCurcumin is a compound that occurs in the rhizomes of the turmeric plant (Curcuma longa) and has shown potential for the treatment of illnesses including certain neurodegenerative diseases. The bioavailability of curcumin is hindered by its extremely poor aqueous solubility.ResultsThis study aimed to apply formulation strategies such as inclusion complex formation with hydroxypropyl-β-cyclodextrin (HPβCD), as well as amorphous solid dispersion (ASD) formation with poly(vinylpyrrolidone-co-vinyl acetate) (PVP VA64) and hydroxypropyl methylcellulose (HPMC) to increase curcumin’s solubility and thereby its nasal epithelial membrane permeation. The curcumin formulations were evaluated by means of DSC, TGA, FT-IR, XRPD, microscopic imaging, aqueous solubility and membrane permeation across nasal respiratory and olfactory epithelial membranes. The solubility of curcumin was substantially increased by the formulations from 8.4 µg/ml for the curcumin raw material to 79.0 µg/ml for the HPβCD inclusion complex, 256.4 µg/ml for the HPMC ASD and 314.9 µg/ml for the PVP VA64 ASD. The HPMC ASD only slightly changed the membrane permeation of curcumin, while the PVP VA64 ASD decreased the membrane permeation of curcumin. The HPβCD inclusion complex enhanced the nasal epithelial membrane permeation of curcumin statistically significantly across the olfactory epithelial tissue and extensively across the respiratory epithelial tissue.ConclusionComplexation of curcumin with HPβCD enhanced the solubility of curcumin and thereby also increased its permeation across excised nasal respiratory and olfactory epithelial tissue. This indicated high potential of the curcumin-HPβCD complex for nose-to-brain delivery of curcumin for treatment of neurodegenerative diseases by means of intranasal administration.Graphical abstract

Exposure to polyhexamethyleneguanidine phosphate in early life dampens pulmonary damage compared to adult mice

Polyhexamethyleneguanidine phosphate (PHMG-P) is a biocide of guanidine family that can cause a fatal lung damage if exposed directly to the lungs. No reports exist regarding the toxicity of PHMG-P in neonatal animals. Therefore, this study aimed to determine PHMG-P toxicity in neonatal and 8-week-old mice after they were intranasally instilled with 1.5 mg/kg, 3 mg/kg, and 4.5 mg/kg PHMG-P. PHMG-P lung exposure resulted in more severe pulmonary toxicity in adult mice than in newborn mice. In the high-dose group of newborn mice, a minimal degree of inflammatory cell infiltration and fibrosis in the lung were detected, whereas more severe pathological lesions including granulomatous inflammation, fibrosis, and degeneration of the bronchiolar epithelium were observed in adult mice. At day 4, C–C motif chemokine ligand 2 (CCL2), a potent chemokine for monocytes, was upregulated but recovered to normal levels at day 15 in newborn mice. However, increased CCL2 and IL-6 levels were sustained at day 15 in adult mice. When comparing the differentially expressed genes of newborn and adult mice through RNA-seq analysis, there were expression changes in several genes associated with inflammation in neonates that were similar or different from those in adults. Although no significant lung damage occurred in newborns, growth inhibition was observed which was not reversed until the end of the experiment. Further research is needed to determine how growth inhibition from neonatal exposure to PHMG-P affects adolescent and young adult health.

Intranasal Immunization of Pneumococcal pep27 Mutant Attenuates Allergic and Inflammatory Diseases by Upregulating Skin and Mucosal Tregs.

Conventional immunization methods such as intramuscular injections lack effective mucosal protection against pathogens that enter through the mucosal surfaces. Moreover, conventional therapy often leads to adverse events and compromised immunity, followed by complicated outcomes, leading to the need to switch to other options. Thus, a need to develop safe and effective treatment with long-term beneficial outcomes to reduce the risk of relapse is mandatory. Mucosal vaccines administered across mucosal surfaces, such as the respiratory or intestinal mucosa, to prompt robust localized and systemic immune responses to prevent the public from acquiring pathogenic diseases. Mucosal immunity contains a unique immune cell milieu that selectively identify pathogens and limits the transmission and progression of mucosal diseases, such as allergic dermatitis and inflammatory bowel disease (IBD). It also offers protection from localized infection at the site of entry, enables the clearance of pathogens on mucosal surfaces, and leads to the induction of long-term immunity with the ability to shape regulatory responses. Regulatory T (Treg) cells have been a promising strategy to suppress mucosal diseases. To find advances in mucosal treatment, we investigated the therapeutic effects of intranasal pep27 mutant immunization. Nasal immunization protects mucosal surfaces, but nasal antigen presentation appears to entail the need for an adjuvant to stimulate immunogenicity. Here, a novel method is developed to induce Tregs via intranasal immunization without an adjuvant to potentially overcome allergic diseases and gut and lung inflammation using lung-gut axis communication in animal models. The implementation of the pep27 mutant for these therapies should be preceded by studies on Treg resilience through clinical translational studies on dietary changes.

Primary nasal influenza infection rewires tissue-scale memory response dynamics

The nasal mucosa is often the initial site of respiratory viral infection, replication, and transmission. Understanding how infection shapes tissue-scale primary and memory responses is critical for designing mucosal therapeutics and vaccines. We generated a single-cell RNA-sequencing atlas of the murine nasal mucosa, sampling three regions during primary influenza infection and rechallenge. Compositional analysis revealed restricted infection to the respiratory mucosa with stepwise changes in immune and epithelial cell subsets and states. We identified and characterized a rare subset of Krt13+ nasal immune-interacting floor epithelial (KNIIFE) cells, which concurrently increased with tissue-resident memory T (TRM)-like cells. Proportionality analysis, cell-cell communication inference, and microscopy underscored the CXCL16-CXCR6 axis between KNIIFE and TRM cells. Secondary influenza challenge induced accelerated and coordinated myeloid and lymphoid responses without epithelial proliferation. Together, this atlas serves as a reference for viral infection in the upper respiratory tract and highlights the efficacy of local coordinated memory responses.

Mucin-induced surface dispersal of Staphylococcus aureus and Staphylococcus epidermidis via quorum-sensing dependent and independent mechanisms.

Despite lacking classical motility machinery, nasopharyngeal staphylococci spread rapidly in (peri)oral and respiratory mucosa and cause cross-infections. We describe laboratory conditions for the reproducible study of staphylococcal dispersal on mucosa-like surfaces and the identification of two dispersal stages (colony spreading and dendritic expansion) stimulated by mucin glycoproteins. The mucin type mattered as dispersal required the surfactant activity and hydration provided by some mucin glycoproteins. While colony spreading was a passive mode of dispersal lubricated by the mucins, the more rapid and invasive form of dendritic expansion of Staphylococcus aureus and Staphylococcus epidermidis required additional lubrication by surfactant-active peptides (phenol-soluble modulins) secreted at high cell densities through quorum sensing. These results highlight a hitherto unknown role for gel-forming mucins in the dispersal of staphylococcal strains associated with cross-infections and point at perioral regions as overlooked sources of carriage and infection by staphylococci.

Oleoresin Capsicum (OC) Spray: An Assessment of Respiratory Health and its Management Following Accidental and Deliberate Exposures.

Introduced into law enforcement in 1976, the oleoresin capsicum (OC) spray has been labeled as one of the most significant and radical developments in law enforcement. However, epidemiological research on OC health effects is deficient, receiving little public support. The major responses to acute exposure to OC spray can be found in the pulmonary system. The molecular mechanism(s) involved in the action of capsaicinoids, the active constituents in OC, are complex cascades of reactions which end up in necrosis or apoptosis. OC may also damage and deplete biological redox systems in the epithelial lining fluids and within cells and mitochondria, modifying structural proteins and nucleic acids and leading to enzyme inactivation. Since there are no characteristic laboratory tests available for identification or confirmation of OC exposure, and on the basis of prevailing data, reassessment of the health risks of OC exposures in vulnerable populations and in-depth study of the molecular mechanics of receptors is the need of the hour for the development of effective countermeasures. This review aims to consider evidence for adverse effects of OC spray used in ways comparable to their application by law enforcement personnel and civilians, with possible treatment recommendations that are precedent for improved management.

The Role of Interleukin 17 Cytokine in Asthma and Its Relation with Severity of Attack

Background: Several reviews have shown a pro-inflammatory role of Interleukin-17 (IL-17) level and have an association to numerous inflammatory illnesses, like rheumatoid arthritis, allograft rejection, systemic lupus erythematosus, and asthma. The T helper-17 (Th-17) cellular fraction of CD4+ T-cells that have been involved as the principal pathogenic cells in a variety of illnesses that has an autoimmune base, produce the cytokine interleukin-17A (IL-17A). Asthma is a chronic inflammatory disease associated with recurrent airways obstruction that is relieved either spontaneously or with medications. Both innate and adaptive immunogenic cells in asthma collaborate with respiratory epithelium to generate "bronchial hyper-reactivity (BHR)". To determine the role of IL-17 in asthmatic patients and the relationship between IL-17 and asthma severity. Results: IL-17 revealed a significant (p-0.001) rise in the values of IL-17 among asthmatic cases (mean = 176.6) compared to healthy controls (mean=22.55). The difference in IL-17 levels between severe and mild asthma was also significant, with a p-value of 0.005. Conclusion: This study suggests that there was a significant difference in the concentrations of IL-17 between asthmatics and healthy control (p-0.001). In severe asthma, IL-17 levels are significantly (p-0.005) higher than in mild/moderate asthma.

FEATURES OF ANESTHESIA IN PATIENTS WITH SPECIAL NEEDS. PART 1

The non-medical use of cannabis can negatively impact the morpho-functional state of almost all organs and systems of the human body. During acute intoxication and established drug dependence, it can unevenly distort the effects of drugs for local and general anesthesia, leading to life-threatening complications. Part 1 of this review presents the results of acute and chronic cannabis use on homeostasis. Cerebral vasospasm and atherosclerosis are identified as major etiological factors for cannabis-related cerebrovascular diseases. Young to middle-aged individuals (30–50 years), male gender (male-to-female ratio 3.7:1), and chronic use (86%) are significant independent predictors of neurovascular toxicity, cerebral hypoperfusion, and stroke. Cannabis smoking causes damage to the respiratory mucosa similar to tobacco. Regular cannabis smokers can expect irritation of the upper respiratory tract, swelling, obstruction, chronic cough, bronchitis, lung emphysema, and bronchospasm. Some reports advocate the use of dexamethasone during surgery to alleviate these symptoms. The detrimental effects of chronic cannabis use on liver and kidney functions are somewhat overstated. Disturbances in immune system, thermoregulation, blood clotting, and carbohydrate metabolism in the absence of anesthetic precautions can significantly complicate the patient's condition in the perioperative period. Cannabinoids can interact with drugs from various groups. Awareness of the pathophysiological and biochemical consequences of cannabis use allows anesthesiologists to anticipate and effectively manage perioperative complications in this patient category

A Molecular and Histopathological Study on Bronchopneumonia in Cats

In this study, it was aimed to determine Bordetella bronchiseptica, Mycoplasma felis, Staphylococcus aureus and Chlamydia felis, which cause bronchopneumonia in cats, by Real-time PCR and to compare the pathological findings of the identified agents. The material of the study was constituted of paraffin blocks belonging to the lungs, of which 21 bronchopneumonia were detected in microscopic examination (with Hematoxylin Eosin (HE)) from a total of 78 cats samples brought to Selcuk University, Faculty of Veterinary Medicine, Department of Pathology for pathological diagnosis. Histopathologically, polymorphonuclear leukocytes (PMNL) and mononuclear cell infiltration (MCI) in the bronchi and bronchiolar lumens, desquamation in the bronchi and bronchiolar epithelium, PMNL infiltration with oedama in alveolar lumens and desquamated alveolar epithelium, PMNL infiltration in the interstitium, and peribronchi and peribronchiolar MCI, and pleuritis were detected. Real-time PCR analysis revealed Bordetella bronchiseptica in 3 (14.29%) cases, Mycoplasma felis in 3 (14.29%), Staphylococcus aureus in 5 (23.8%), and Chlamydia felis in 5 (23.8%). Morever, Mycoplasma felis and Staphylococcus aureus infection was detected in 1 case, and Staphylococcus aureus and Chlamydia felis mixed infection was observed in 1 case. Our results show that relevant agents can frequently be isolated in cases of feline bronchopneumonia.

Systemic prime mucosal boost significantly increases protective efficacy of bivalent RSV influenza viral vectored vaccine

Although licensed vaccines against influenza virus have been successful in reducing pathogen-mediated disease, they have been less effective at preventing viral infection of the airways and current seasonal updates to influenza vaccines do not always successfully accommodate viral drift. Most licensed influenza and recently licensed RSV vaccines are administered via the intramuscular route. Alternative immunisation strategies, such as intranasal vaccinations, and “prime-pull” regimens, may deliver a more sterilising form of protection against respiratory viruses. A bivalent ChAdOx1-based vaccine (ChAdOx1-NP + M1-RSVF) encoding conserved nucleoprotein and matrix 1 proteins from influenza A virus and a modified pre-fusion stabilised RSV A F protein, was designed, developed and tested in preclinical animal models. The aim was to induce broad, cross-protective tissue-resident T cells against heterotypic influenza viruses and neutralising antibodies against RSV in the respiratory mucosa and systemically. When administered via an intramuscular prime-intranasal boost (IM-IN) regimen in mice, superior protection was generated against challenge with either RSV A, Influenza A H3N2 or H1N1. These results support further clinical development of a pan influenza & RSV vaccine administered in a prime-pull regimen.

Physiological and biochemical studies of young sterlet sturgeon (Acipenser ruthenus L.) in the lower reaches of the Volga river

In conditions of a decrease in the number of rolled sturgeon larvae in the lower reaches of the Volga River, an urgent issue is the study of the physiological and biochemical parameters of the fish organism. The purpose of this work is to conduct physiological and biochemical studies of juvenile sterlet (Acipenser ruthenus L, 1758). The study of fish was carried out using the methods of classical histology and biochemistry. The degree of damage to the gills and liver was assessed on a scale from 1 to 5 points. The content of total lipids and water-soluble protein in the muscle tissue of sterlet fingerlings was studied as biochemical parameters. The morphological picture of the gills of 80% of the fish corresponded to a weakly pronounced character of changes (2 points), while in others it was characterized by the presence of a borderline state between weakly pronounced changes and moderate injuries (2–3 points). Six types of disorders were found in the gills: hyperplasia of the respiratory epithelium of lamellae, dilation of the blood vessel of the filament, goblet-shaped swellings of the apical part of the filament, invasions, expansion of the apical part of the lamellae, proliferation of connective tissue of lamellae. In the liver of 80% of fish, a borderline state was recorded between mild changes and moderate damage (2–3 points), in 13.3% of individuals the liver had mild damage (2 points), in 6.7% there were medium damage (3 points). Four types of disorders were found in the liver of juvenile sterlet: fullness of the liver capillaries, pronounced venous fullness, cavities, capillary dilation. In the muscle tissue of fingerlings, the concentrations of total lipids were in the range of 1.39–5.28%, and water-soluble protein — 45.59–57.97 mg/g. The study of the physiological and biochemical parameters of juvenile sturgeon in the lower reaches of the Volga River is very important for the biology of the species and monitoring the natural reproduction of these valuable fish species.

SARS-CoV-2 Accessory Protein ORF8 Targets the Dimeric IgA Receptor pIgR.

SARS-CoV-2 is a highly pathogenic respiratory virus that successfully initiates and establishes its infection at the respiratory mucosa. However, little is known about how SARS-CoV-2 antagonizes the host's mucosal immunity. Recent findings have shown a marked reduction in the expression of the polymeric Ig receptor (pIgR) in COVID-19 patients. This receptor maintains mucosal homeostasis by transporting the dimeric IgA (dIgA) and pentameric IgM (pIgM) across mucosal epithelial cells to neutralize the invading respiratory pathogens. By studying the interaction between pIgR and SARS-CoV-2 proteins, we discovered that the viral accessory protein Open Reading Frame 8 (ORF8) potently downregulates pIgR expression and that this downregulation activity of ORF8 correlates with its ability to interact with pIgR. Importantly, the ORF8-mediated downregulation of pIgR diminishes the binding of dIgA or pIgM, and the ORF8 proteins of the variants of concern of SARS-CoV-2 preserve the function of downregulating pIgR, indicating the importance of this conserved activity of ORF8 in SARS-CoV-2 pathogenesis. We further observed that the secreted ORF8 binds to cell surface pIgR, but that this interaction does not trigger the cellular internalization of ORF8, which requires the binding of dIgA to pIgR. These findings suggest the role of ORF8 in SARS-CoV-2 mucosal immune evasion.

Imipenem reduces the efficacy of vancomycin against Elizabethkingia species.

Elizabethkingia spp. are emerging as nosocomial pathogens causing various infections. These pathogens express resistance to a broad range of antibiotics, thus requiring antimicrobial combinations for coverage. However, possible antagonistic interactions between antibiotics have not been thoroughly explored. This study aimed to evaluate the effectiveness of antimicrobial combinations against Elizabethkingia infections, focusing on their impact on pathogenicity, including biofilm production and cell adhesion. Double-disc diffusion, time-kill, and chequerboard assays were used for evaluating the combination effects of antibiotics against Elizabethkingia spp. We further examined the antagonistic effects of antibiotic combinations on biofilm formation and adherence to A549 human respiratory epithelial cells. Further validation of the antibiotic interactions and their implications was performed using ex vivo hamster precision-cut lung sections (PCLSs) to mimic in vivo conditions. Antagonistic effects were observed between cefoxitin, imipenem and amoxicillin/clavulanic acid in combination with vancomycin. The antagonism of imipenem toward vancomycin was specific to its effects on the genus Elizabethkingia. Imipenem further hampered the bactericidal effect of vancomycin and impaired its inhibition of biofilm formation and the adhesion of Elizabethkingia meningoseptica ATCC 13253 to human cells. In the ex vivo PCLS model, vancomycin exhibited dose-dependent bactericidal effects; however, the addition of imipenem also reduced the effect of vancomycin. Imipenem reduced the bactericidal efficacy of vancomycin against Elizabethkingia spp. and compromised its capacity to inhibit biofilm formation, thereby enhancing bacterial adhesion. Clinicians should be aware of the potential issues with the use of these antibiotic combinations when treating Elizabethkingia infections.