An adjuvant strategy enabled by modulation of the physical properties of microbial ligands expands antigen immunogenicity.

Activation of the innate immune system via pattern recognition receptors (PRRs) is key to generate lasting adaptive immunity. PRRs detect unique chemical patterns associated with invading microorganisms, but whether and how the physical properties of PRR ligands influence the development of the immune response remains unknown. Through the study of fungal mannans, we show that the physical form of PRR ligands dictates the immune response. Soluble mannans are immunosilent in the periphery but elicit a potent pro-inflammatory response in the draining lymph node (dLN). By modulating the physical form of mannans, we developed a formulation that targets both the periphery and the dLN. When combined with viral glycoprotein antigens, this mannan formulation broadens epitope recognition, elicits potent antigen-specific neutralizing antibodies, and confers protection against viral infections of the lung. Thus, the physical properties of microbial ligands determine the outcome of the immune response and can be harnessed for vaccine development.

Endogenous oxidized phospholipids reprogram cellular metabolism and boost hyperinflammation.

Pathogen-associated molecular patterns (PAMPs) have the capacity to couple inflammatory gene expression to changes in macrophage metabolism, both of which influence subsequent inflammatory activities. Similar to their microbial counterparts, several self-encoded damage-associated molecular patterns (DAMPs) induce inflammatory gene expression. However, whether this symmetry in host responses between PAMPs and DAMPs extends to metabolic shifts is unclear. Here, we report that the self-encoded oxidized phospholipid oxPAPC alters the metabolism of macrophages exposed to lipopolysaccharide. While cells activated by lipopolysaccharide rely exclusively on glycolysis, macrophages exposed to oxPAPC also use mitochondrial respiration, feed the Krebs cycle with glutamine, and favor the accumulation of oxaloacetate in the cytoplasm. This metabolite potentiates interleukin-1ß production, resulting in hyperinflammation. Similar metabolic adaptions occur in vivo in hypercholesterolemic mice and human subjects. Drugs that interfere with oxPAPC-driven metabolic changes reduce atherosclerotic plaque formation in mice, thereby underscoring the importance of DAMP-mediated activities in pathophysiological conditions.

Inhibition of transcription factor NFAT activity in activated platelets enhances their aggregation and exacerbates gram-negative bacterial septicemia.

During gram-negative septicemia, interactions between platelets and neutrophils initiate a detrimental feedback loop that sustains neutrophil extracellular trap (NET) induction, disseminated intravascular coagulation, and inflammation. Understanding intracellular pathways that control platelet-neutrophil interactions is essential for identifying new therapeutic targets. Here, we found that thrombin signaling induced activation of the transcription factor NFAT in platelets. Using genetic and pharmacologic approaches, as well as iNFATuation, a newly developed mouse model in which NFAT activation can be abrogated in a cell-specific manner, we demonstrated that NFAT inhibition in activated murine and human platelets enhanced their activation and aggregation, as well as their interactions with neutrophils and NET induction. During gram-negative septicemia, NFAT inhibition in platelets promoted disease severity by increasing disseminated coagulation and NETosis. NFAT inhibition also partially restored coagulation ex vivo in patients with hypoactive platelets. Our results define non-transcriptional roles for NFAT that could be harnessed to address pressing clinical needs.

Aged vasculature drives neutrophils mad.

Inflammaging drives age-related pathologies. In this issue of Immunity, Barkaway et al. illustrate how aged endothelial cells and mast cells promote reverse migration of neutrophils from inflamed tissue back into circulation, causing tissue damage at distal sites.

Prioritized mass spectrometry increases the depth, sensitivity and data completeness of single-cell proteomics.

Major aims of single-cell proteomics include increasing the consistency, sensitivity and depth of protein quantification, especially for proteins and modifications of biological interest. Here, to simultaneously advance all these aims, we developed prioritized Single-Cell ProtEomics (pSCoPE). pSCoPE consistently analyzes thousands of prioritized peptides across all single cells (thus increasing data completeness) while maximizing instrument time spent analyzing identifiable peptides, thus increasing proteome depth. These strategies increased the sensitivity, data completeness and proteome coverage over twofold. The gains enabled quantifying protein variation in untreated and lipopolysaccharide-treated primary macrophages. Within each condition, proteins covaried within functional sets, including phagosome maturation and proton transport, similarly across both treatment conditions. This covariation is coupled to phenotypic variability in endocytic activity. pSCoPE also enabled quantifying proteolytic products, suggesting a gradient of cathepsin activities within a treatment condition. pSCoPE is freely available and widely applicable, especially for analyzing proteins of interest without sacrificing proteome coverage. Support for pSCoPE is available at http://scp.slavovlab.net/pSCoPE .

By Capturing Inflammatory Lipids Released from Dying Cells, the Receptor CD14 Induces Inflammasome-Dependent Phagocyte Hyperactivation.

A heterogeneous mixture of lipids called oxPAPC, derived from dying cells, can hyperactivate dendritic cells (DCs) but not macrophages. Hyperactive DCs are defined by their ability to release interleukin-1 (IL-1) while maintaining cell viability, endowing these cells with potent aptitude to stimulate adaptive immunity. Herein, we found that the bacterial lipopolysaccharide receptor CD14 captured extracellular oxPAPC and delivered these lipids into the cell to promote inflammasome-dependent DC hyperactivation. Notably, we identified two specific components within the oxPAPC mixture that hyperactivated macrophages, allowing these cells to release IL-1 for several days, by a CD14-dependent process. In murine models of sepsis, conditions that promoted cell hyperactivation resulted in inflammation but not lethality. Thus, multiple phagocytes are capable of hyperactivation in response to oxPAPC, with CD14 acting as the earliest regulator in this process, serving to capture and transport these lipids to promote inflammatory cell fate decisions.

Homodimeric Granzyme A Opsonizes Mycobacterium tuberculosis and Inhibits Its Intracellular Growth in Human Monocytes via Toll-Like Receptor 4 and CD14.

Mycobacterium tuberculosis (Mtb)-specific γ9δ2 T cells secrete granzyme A (GzmA) protective against intracellular Mtb growth. However, GzmA-enzymatic activity is unnecessary for pathogen inhibition, and the mechanisms of GzmA-mediated protection remain unknown. We show that GzmA homodimerization is essential for opsonization of mycobacteria, altered uptake into human monocytes, and subsequent pathogen clearance within the phagolysosome. Although monomeric and homodimeric GzmA bind mycobacteria, only homodimers also bind cluster of differentiation 14 (CD14) and Toll-like receptor 4 (TLR4). Without access to surface-expressed CD14 and TLR4, GzmA fails to inhibit intracellular Mtb. Upregulation of Rab11FIP1 was associated with inhibitory activity. Furthermore, GzmA colocalized with and was regulated by protein disulfide isomerase AI (PDIA1), which cleaves GzmA homodimers into monomers and prevents Mtb inhibitory activity. These studies identify a previously unrecognized role for homodimeric GzmA structure in opsonization, phagocytosis, and elimination of Mtb in human monocytes, and they highlight PDIA1 as a potential host-directed therapy for prevention and treatment of tuberculosis, a major human disease.

Retinal thinning in progressive supranuclear palsy: differences with healthy controls and correlation with clinical variables.

BACKGROUND: Available evidence reports conflicting data on retinal thickness in progressive supranuclear palsy (PSP). In studies including healthy controls, PSP showed either the thinning of the retinal nerve fiber layer, macular ganglion cell, inner nuclear, or outer retina layer. OBJECTIVES: The goals of the present study were to describe retinal layer thickness in a large cohort of PSP compared to healthy controls and in PSP phenotypes using spectral-domain optical coherence tomography (SD-OCT). The additional objective was to verify the relationship between retinal layers thickness and clinical variables in PSP. METHODS: Using a cross-sectional design, we examined retinal structure in 27 PSP patients and 27 controls using standard SD-OCT. Motor and cognitive impairment in PSP was rated with the PSP rating scale and the Montreal Cognitive Assessment battery (MoCA), respectively. Eyes with poor image quality or confounding diseases were excluded. SD-OCT measures of PSP and controls were compared with parametric testing, and correlations between retinal layer thicknesses and disease severity were evaluated. RESULTS: PSP showed significant thinning of the inner retinal layer (IRL), ganglion cell layer (GCL), inner plexiform layer (IPL), and the outer plexiform layer (OPL) compared to healthy controls. PSP phenotypes showed similar retinal layer thicknesses. Retinal layer thickness correlated with MoCA visuospatial subscore (p < 0.001). CONCLUSIONS: We demonstrated PSP patients disclosed thinner IRL, GCL, IPL, and OPL compared to healthy controls. Furthermore, we found a significant correlation between visuospatial abilities and retinal layers suggesting the existence of a mutual relationship between posterior cognitive function and retinal structure.

Choroidal evaluation in patients under alpha-lytic therapy.

PURPOSE: To detect any choroidal thickness (CT) change in patients after alpha-lytic drugs withdrawal that could help in the cataract surgery timing decision. METHODS: Twenty-five eyes of 25 patients (mean age: 76 ± 7 years) under alpha-lytic therapy, and 25 eyes of 25 control subjects (CS) (mean age: 75 ± 7 years) without alpha-lytic therapy, both scheduled for cataract surgery in the fellow eye, were included in this observational, prospective, non-randomized study. All patients underwent EDI-OCT during the first preoperative visit and approximately 1 month (range 28-31 days) after alpha-lytic withdrawal. In the CS group, the OCT during preoperative visit and approximately 1 month after (range 28-31 days) the first examination was performed. Data normality with Kolmogorov-Smirnov test was checked and statistical evaluation with the Wilcoxon-signed rank test was performed. RESULTS: The mean subfoveal CT was 224 ± 79.7 µm during therapy and 217 ± 70.4 µm after withdrawal; 1.5 mm nasally from the fovea CT was 198 ± 83.8 µm and 194 ± 82.8 µm, respectively; and 1.5 mm temporally from the fovea CT was 217 ± 55.9 µm and 205 ± 54.4 µm, respectively. A statistically significant reduction (p < 0.05) in all the 3 measured CT points was found. In the CS no significant changes were detected (p > 0.05). CONCLUSION: No severe floppy iris syndrome was detected at the time of surgery. In these patients, CT decrease could be an important sign for cataract surgery timing decision.

The Effect of Esophagogastroduodenoscopy on Intraocular Pressure.

BACKGROUND: Esophagogastroduodenoscopy (EGD) is an endoscopic examination of the upper gastrointestinal tract that requires insufflation with gas, leading to intra-abdominal hypertension (IAH). There is evidence suggesting that IAH positively correlates with intracranial pressure (ICP) and possibly with intraocular pressure (IOP). The aim of this study was to examine the effect of a routine screening EGD on the IOP. METHODS: In this observational study, 25 patients were recruited; 15 males with a mean age of 50 ± 18 years and 10 females with a mean age of 45 ± 14 years. EGD was conducted under sedation in 21 subjects. Both eyes' IOP measurements were performed using Tonopen Avia in the sitting and left lateral decubitus positions before sedation and the start of EGD, and subsequently in the left lateral decubitus position when the endoscope reached the duodenum (D2) and at the end of the procedure. The final measurement was performed in the sitting position 10 min after the end of the procedure. RESULTS: The mean IOP in the sitting position was 15.16 ± 2.27 mmHg, and in the left lateral decubitus position, 15.68 ± 2.82 mmHg. When the gastroscope entered the D2, it was 21.84 ± 6.55 mmHg, at the end of the procedure, 15.80 ± 3.25 mmHg, and 10 min later, 13.12 ± 3.63 mmHg. There was a statistically significant IOP increase when the gastroscope entered the duodenum (p < 0.01). At the end of the gastroscopy, the IOP significantly decreased compared to the one registered when the gastroscope entered the D2 (p < 0.001) and it became similar to the values measured before the EGD, in the same left lateral decubitus position (p > 0.05). CONCLUSION: Significant changes in IOP were observed during the EGD. IOP fluctuations during EGD should be taken into account, especially in patients that need repeated EGDs during their life or in patients with glaucoma. Further studies are needed to better understand the short-effect and long-effect influence of an IOP increase in these patients.

Impact of Brightness on Choroidal Vascularity Index.

The use of choroidal vascularization to diagnose and follow-up ocular and systemic pathologies has been consolidated in recent research. Unfortunately, the choroidal parameters can be different depending on the lighting settings of optical coherence tomography (OCT) images. The purpose of this study was to examine whether the brightness of OCT images could influence the measurements of choroidal parameters obtained by processing and analyzing scientific images with the ImageJ program. In this observational, prospective, non-randomized study, 148 eyes of 74 patients with a mean age of 30.7 ± 8.5 years (ranging from 23 to 61 years) were assessed. All patients underwent a complete ophthalmological examination including slit lamp, fundus oculi, ocular biometry, corneal tomography and spectral domain (SD) OCT evaluations of the foveal region in the enhanced depth imaging (EDI) mode. OCT images at two different brightness levels were obtained. The total choroidal area (TCA), choroidal vascularity index (CVI), stromal choroidal area (SCA) and luminal choroidal area (LCA) at both lower and higher brightness levels were measured. To avoid the bias of operator-dependent error, the lower and higher brightness TCAs were obtained using two methods: the manual tracking mode and fixed area. At the two different brightness levels, LCA, SCA and CVI measurements showed statistically significant changes (p < 0.05), whereas the TCA differences were not statistically significant (p > 0.05). According to the results of this study, highlighting that brightness could affect LCA, SCA and CVI parameters, care should be taken during OCT image acquisition.

Effect of Interscalene Brachial Plexus Block on Intracranial Pressure: Are the Measures of Optic Nerve Sheath Diameter Standardised with B-Scan?

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Comment on Naranjo-Bonilla et al. Retinal and Choroidal Effects of Continuous Positive Airway Pressure as Treatment for Sleep Apnea: Results at 12 Months. Int. J. Environ. Res. Public Health 2022, 19, 12637.

We read with great interest the article by Naranjo-Bonilla et al. concerning changes in retinal and choroidal thickness (ChT) in patients with obstructive sleep apnea (OSA) who underwent continuous positive airway pressure treatment (CPAP) [...].