Systemic Proinflammatory Response Research Articles

Targeted delivery of flagellin by nebulization offers optimized respiratory immunity and defense against pneumococcal pneumonia.

Novel therapeutic strategies are urgently needed to combat pneumonia caused by Streptococcus pneumoniae strains resistant to standard-of-care antibiotics. Previous studies have shown that targeted stimulation of lung innate immune defenses through intranasal administration of the Toll-like receptor 5 agonist flagellin improves the treatment of pneumonia when combined with antibiotics. To promote translation to the clinic application, this study assessed the direct delivery of flagellin to the airways through nebulization using a vibrating mesh nebulizer in mice. Intranasal delivery achieved approximately 40% lung deposition of the administered flagellin dose, whereas nebulization yielded less than 1%. Despite these differences, nebulized flagellin induced transient activation of lung innate immunity characterized by cytokine/chemokine production and neutrophil infiltration into airways analogous to intranasal administration. Furthermore, inhalation by nebulization resulted in an accelerated resolution of systemic pro-inflammatory responses. Lastly, adjunct therapy combining nebulized flagellin and amoxicillin proved effective against antibiotic-resistant pneumococcal pneumonia in mice. We posit that flagellin aerosol therapy represents a safe and promising approach to address bacterial pneumonia within the context of antimicrobial resistance.

Systemic pro-inflammatory response following bronchoscopic lung volume reduction using endobronchial valves

RationaleBronchoscopic lung volume reduction treatment using endobronchial valves (EBV) is an effective treatment for severe COPD patients by improving lung function and quality of life. However, little is known about its effects on systemic inflammation. Therefore, the aim of our study was to investigate whether EBV treatment impacts the inflammatory cytokine profile.MethodsThis study was a predefined substudy of the SoLVE trial (NCT03474471) that investigated the combination of EBV treatment with pulmonary rehabilitation (PR). The substudy included the collection of blood samples with assessment of 10 inflammatory markers prior to EBV treatment and 6 months after EBV or EBV+PR treatment.ResultsIn 66 patients, six months after treatment a pro-inflammatory cytokine profile was observed, with an increase in all pro-inflammatory markers and a decrease in the anti-inflammatory cytokine IL-10. The changes in plasma cytokine profile were not associated with changes in clinical outcomes such as lung function or exercise capacity.DiscussionIn conclusion, our study demonstrated an elevation in systemic pro-inflammatory cytokine levels following successful EBV-treatment, which was not associated with adverse clinical outcomes. It would be interesting to further explore, whether this increase is attributed to a foreign body response or if other factors contribute to this phenomenon.

Brain and Lung Biomarker Responses to Hyperoxic Hypobaric Decompression.

INTRODUCTION: Biomarker responses to intensive decompression indicate systemic proinflammatory responses and possible neurological stress. To further investigate responses, 12 additional brain and lung biomarkers were assayed.METHODS: A total of 15 healthy men (20 to 50 yr) undertook consecutive same-day ascents to 25,000 ft (7620 m), following denitrogenation, breathing 100% oxygen. Venous blood was sampled at baseline (T0), after the second ascent (T8), and next morning (T24). Soluble protein markers of brain and lung insult were analyzed by enzyme-linked immunosorbent assay with plasma microparticles quantified using flow cytometry.RESULTS: Levels of monocyte chemoattractant protein-1 and high mobility group box protein 1 were elevated at T8, by 36% and 16%, respectively, before returning to baseline. Levels of soluble receptor for advanced glycation end products fell by 8%, recovering by T24. Brain-derived neurotrophic factor rose by 80% over baseline at T24. Monocyte microparticle levels rose by factors of 3.7 at T8 and 2.7 at T24 due to early and late responses in different subjects. Other biomarkers were unaffected or not detected consistently.DISCUSSION: The elevated biomarkers at T8 suggest a neuroinflammatory response, with later elevation of brain-derived neurotrophic factor at T24 indicating an ongoing neurotrophic response and incomplete recovery. A substantial increase at T8 in the ratio of high mobility group box protein 1 to soluble receptor for advanced glycation end products suggests this axis may mediate the systemic inflammatory response to decompression. The mechanism of neuroinflammation is unclear but elevation of monocyte microparticles and monocyte chemoattractant protein-1 imply a key role for activated monocytes and/or macrophages.Connolly DM, Madden LA, Edwards VC, Lee VM. Brain and lung biomarker responses to hyperoxic hypobaric decompression. Aerosp Med Hum Perform. 2024; 95(9):667-674.

Immunostimulatory and immunoadjuvant capacities of soluble Rhamnan-type Ulva oligosaccharides

Algae polysaccharides were discovered to act as pathogen-associated molecular patterns (PAMPs) to trigger immune responses, while bioactivities of oligosaccharides have not been thoroughly explored. Ulva oligosaccharides from Ulva prolifera were obtained using PL25 family ulvan lyase and evaluated for cell viability and phagocytic activity. Ulva oligosaccharides with 542 Da (OUP), consisting of tetrasaccharide (∆UA-RhaS-Xyl-RhaS) and disaccharides (∆UA-RhaS), exhibited the most pronounced phagocytic activities. Besides, OUP could effectively stimulate the expressions of proinflammatory cytokines and chemokines like TNF-α, IL-1β, IL-6, IFN-γ and CXCL1 in primary macrophages and subsequently promote the proliferation and activation of T and B lymphocytes in vitro. Transcriptome analysis also gave rise to the systemic proinflammatory responses triggered by OUP in macrophages, such as activation of multiple PRRs-related signaling pathways and downstream JAK-STAT and NF-κB signaling. Furthermore, in an in vivo mouse OVA immunization model, OUP upregulated the specific anti-OVA IgG antibody production in vivo, pointing to its immunoadjuvant capacity. OUP increases cell proliferation and secretion of IL-4 and IFN-γ of splenocytes in response to OVA stimulation ex vivo, thereby enhancing both Th1 and Th2 immune responses. Collectively, all this data suggests that OUP could function as the immune stimulator to enhance host immune response to infections.

The impact of prior exposure to hypoglycaemia on the inflammatory response to a subsequent hypoglycaemic episode

BackgroundHypoglycaemia has been shown to induce a systemic pro-inflammatory response, which may be driven, in part, by the adrenaline response. Prior exposure to hypoglycaemia attenuates counterregulatory hormone responses to subsequent hypoglycaemia, but whether this effect can be extrapolated to the pro-inflammatory response is unclear. Therefore, we investigated the effect of antecedent hypoglycaemia on inflammatory responses to subsequent hypoglycaemia in humans.MethodsHealthy participants (n = 32) were recruited and randomised to two 2-h episodes of either hypoglycaemia or normoglycaemia on day 1, followed by a hyperinsulinaemic hypoglycaemic (2.8 ± 0.1 mmol/L) glucose clamp on day 2. During normoglycaemia and hypoglycaemia, and after 24 h, 72 h and 1 week, blood was drawn to determine circulating immune cell composition, phenotype and function, and 93 circulating inflammatory proteins including hs-CRP.ResultsIn the group undergoing antecedent hypoglycaemia, the adrenaline response to next-day hypoglycaemia was lower compared to the control group (1.45 ± 1.24 vs 2.68 ± 1.41 nmol/l). In both groups, day 2 hypoglycaemia increased absolute numbers of circulating immune cells, of which lymphocytes and monocytes remained elevated for the whole week. Also, the proportion of pro-inflammatory CD16+-monocytes increased during hypoglycaemia. After ex vivo stimulation, monocytes released more TNF-α and IL-1β, and less IL-10 in response to hypoglycaemia, whereas levels of 19 circulating inflammatory proteins, including hs-CRP, increased for up to 1 week after the hypoglycaemic event. Most of the inflammatory responses were similar in the two groups, except the persistent pro-inflammatory protein changes were partly blunted in the group exposed to antecedent hypoglycaemia. We did not find a correlation between the adrenaline response and the inflammatory responses during hypoglycaemia.ConclusionHypoglycaemia induces an acute and persistent pro-inflammatory response at multiple levels that occurs largely, but not completely, independent of prior exposure to hypoglycaemia.Clinical Trial information Clinicaltrials.gov no. NCT03976271 (registered 5 June 2019).

Synbiotics improve growth performance and nutrient digestibility, inhibit PEDV infection, and prevent intestinal barrier dysfunction by mediating innate antivirus immune response in weaned piglets.

This experiment was conducted to explore the effects of dietary synbiotics (SYB) supplementation on growth performance, immune function, and intestinal barrier function in piglets challenged with porcine epidemic diarrhea virus (PEDV). Forty crossbred (Duroc × Landrace × Yorkshire) weaned piglets (26 ± 1d old) with a mean body weight (BW) of 6.62 ± 0.36kg were randomly allotted to five groups: control (CON) I and CONII group, both fed basal diet; 0.1% SYB group, 0.2% SYB group, and 0.2% yeast culture (YC) group, fed basal diet supplemented with 0.1%, 0.2% SYB, and 0.2% YC, respectively. On day 22, all piglets were orally administrated with 40mL PEDV (5.6 × 103 TCID50/mL) except piglets in CONI group, which were administrated with the same volume of sterile saline. The trial lasted for 26d. Before PEDV challenge, dietary 0.1% SYB supplementation increased final BW, average daily gain (ADG), and decreased the ratio of feed to gain during 0 to 21d (P < 0.05), as well as improved the apparent nutrient digestibility of dry matter (DM), organic matter (OM), crude protein, ether extract (EE), and gross energy (GE). At the same time, 0.2% YC also improved the apparent nutrient digestibility of DM, OM, EE, and GE (P < 0.05). PEDV challenge increased diarrhea rate and diarrhea indexes while decreased ADG (P < 0.05) from days 22 to 26, and induced systemic and intestinal mucosa innate immune and proinflammatory responses, destroyed intestinal barrier integrity. The decrease in average daily feed intake and ADG induced by PEDV challenge was suppressed by dietary SYB and YC supplementation, and 0.1% SYB had the best-alleviating effect. Dietary 0.1% SYB supplementation also increased serum interleukin (IL)-10, immunoglobulin M, complement component 4, and jejunal mucosal IL-4 levels, while decreased serum diamine oxidase activity compared with CONII group (P < 0.05). Furthermore, 0.1% SYB improved mRNA expressions of claudin-1, zonula occludens protein-1, mucin 2, interferon-γ, interferon regulatory factor-3, signal transducers and activators of transcription (P < 0.05), and protein expression of occludin, and downregulated mRNA expressions of toll-like receptor 3 and tumor necrosis factor-α (P < 0.05) in jejunal mucosa. Supplementing 0.2% SYB or 0.2% YC also had a positive effect on piglets, but the effect was not as good as 0.1% SYB. These results indicated that dietary 0.1% SYB supplementation improved growth performance under normal conditions, and alleviated the inflammatory response and the damage of intestinal barrier via improving innate immune function and decreasing PEDV genomic copies, showed optimal protective effects against PEDV infection.

Poly(N-methyl-N-vinylacetamide): A Strong Alternative to PEG for Lipid-Based Nanocarriers Delivering siRNA.

Lipid-based nanocarriers have demonstrated high interest in delivering genetic material, exemplified by the success of Onpattro and COVID-19 vaccines. While PEGylation imparts stealth properties, it hampers cellular uptake and endosomal escape, and may trigger adverse reactions like accelerated blood clearance (ABC) and hypersensitivity reactions (HSR). This work highlights the great potential of amphiphilic poly(N-methyl-N-vinylacetamide) (PNMVA) derivatives as alternatives to lipid-PEG for siRNA delivery. PNMVA compounds with different degrees of polymerization and hydrophobic segments, are synthesized. Among them, DSPE (1,2-distearoyl-sn-glycero-3-phosphoethanolamine)-PNMVA efficiently integrates into lipoplexes and LNP membranes and prevents protein corona formation around these lipid carriers, exhibiting stealth properties comparable to DSPE-PEG. However, unlike DSPE-PEG, DSPE-PNMVA24 shows no adverse impact on lipoplexes cell uptake and endosomal escape. In in vivo study with mice, DSPE-PNMVA24 lipoplexes demonstrate no liver accumulation, indicating good stealth properties, extended circulation time after a second dose, reduced immunological reaction, and no systemic pro-inflammatory response. Safety of DSPE-PNMVA24 is confirmed at the cellular level and in animal models of zebrafish and mice. Overall, DSPE-PNMVA is an advantageous substitute to DSPE-PEG for siRNA delivery, offering comparable stealth and toxicity properties while improving efficacy of the lipid-based carriers by minimizing the dilemma effect and reducing immunological reactions, meaning no ABC or HSR effects.

Contributions of the microbiota to the systemic inflammatory response.

The health of the intestinal microbiota impacts tolerance at homeostasis and the strength of the inflammation response during acute bloodstream infections. A complete understanding of the feedback loop between systemic inflammation and dysregulation of the gut microbiota is necessary for inflammation management. Here we will review the many ways in which the microbiota can influence the systemic pro-inflammatory response. Short-chain fatty acids, produced through the microbial metabolism of dietary fibers, can suppress inflammation systemically; in the absence of a balanced diet or disruption of the microbiota through antibiotics, there is disrupted metabolite production, leading to systemic inflammation. Dysbiosis or inflammation in the intestines can lead to a breakdown of the sturdy intestinal-epithelial barrier. When this barrier is perturbed, immunogenic lipopolysaccharides or extracellular vesicles enter the bloodstream and induce excessive inflammation. Necessary clinical treatments, such as antifungals or antibacterials, induce microbiota dysregulation and thus increased risk of endotoxemia; though probiotics may aid in improving the microbiota health and have been shown to deflate inflammation during sepsis. Within this complicated relationship: What is in control, the dysbiotic microbiota or the systemic inflammation?

Hepatic proinflammatory myeloid phenotypes are a hallmark of Ebola virus Kikwit pathogenesis in rhesus monkeys.

The liver is an early systemic target of Ebola virus (EBOV), but characterization beyond routine histopathology and viral antigen distribution is limited. We hypothesized Ebola virus disease (EVD) systemic proinflammatory responses would be reflected in temporally altered liver myeloid phenotypes. We utilized multiplex fluorescent immunohistochemistry (mfIHC), multispectral whole slide imaging, and image analysis to quantify molecular phenotypes of myeloid cells in the liver of rhesus macaques (Macaca mulatta; n = 21) infected with EBOV Kikwit. Liver samples included uninfected controls (n = 3), 3 days postinoculation (DPI; n = 3), 4 DPI (n = 3), 5 DPI (n = 3), 6 DPI (n = 3), and terminal disease (6-8 DPI; n = 6). Alterations in hepatic macrophages occurred at ≥ 5 DPI characterized by a 1.4-fold increase in CD68+ immunoreactivity and a transition from primarily CD14-CD16+ to CD14+CD16- macrophages, with a 2.1-fold decrease in CD163 expression in terminal animals compared with uninfected controls. An increase in the neutrophil chemoattractant and alarmin S100A9 occurred within hepatic myeloid cells at 5 DPI, followed by rapid neutrophil influx at ≥ 6 DPI. An acute rise in the antiviral myxovirus resistance protein 1 (MxA) occurred at ≥ 4 DPI, with a predilection for enhanced expression in uninfected cells. Distinctive expression of major histocompatibility complex (MHC) class II was observed in hepatocytes during terminal disease. Results illustrate that EBOV causes macrophage phenotype alterations as well as neutrophil influx and prominent activation of interferon host responses in the liver. Results offer insight into potential therapeutic strategies to prevent and/or modulate the host proinflammatory response to normalize hepatic myeloid functionality.

Citrulline, Intestinal Fatty Acid-Binding Protein and the Acute Gastrointestinal Injury Score as Predictors of Gastrointestinal Failure in Patients with Sepsis and Septic Shock.

Gastrointestinal (GI) failure can be both a cause of sepsis and a consequence of the systemic pro-inflammatory response in sepsis. Changes in biomarkers of enterocyte damage, citrulline and I-FABP (intestinal fatty acid binding protein), may indicate altered intestinal permeability and damage. The study group consisted of patients with sepsis (N = 28) and septic shock (N = 30); the control group included patients without infection (N = 10). Blood samples were collected for citrulline and I-FABP and a 4-point AGI score (acute GI injury score) was calculated to monitor GI function on days 1, 3, 5, 7, and 10. Citrulline concentrations in the study group were lower than in the control. Lower values were also noted in septic patients with shock when compared to the non-shock group throughout the study period. I-FABP was higher in the septic shock group than in the sepsis group only on days 1 and 3. Citrulline was lower in patients with GI failure (AGI III) when compared to AGI I/II, reaching significance on days 7 (p = 0.034) and 10 (p = 0.015); moreover, a higher AGI score was associated with an increased 28 day mortality (p = 0.038). The results indicate that citrulline measurements, along with the AGI assessment, have clinical potential in monitoring GI function and integrity in sepsis.

Abstract 815: Improved tolerability and tumor specific delivery of a therapeutic bispecific T cell engager using a pH-sensitive nanoparticle platform

Abstract Bispecific antibodies are an emerging class of therapeutics for immune-oncology applications. T cell engagers (TCEs) target tumor-associated antigens (TAA) to eradicate cancer cells. TCEs for solid tumors have demonstrated encouraging preclinical efficacy but development has been challenging with dose-limiting toxicities due to on-target/off-tumor effect. To overcome the issue, we have developed ON-BOARD, an ultra-pH sensitive nanoparticle platform for masked and targeted delivery of payloads to the acidic tumor microenvironment (TME). Herein we report efficacious masked delivery of a TCE to tumors in mice using ON-BOARD demonstrating significantly improved tolerability and potential for clinical translation. TCEs were encapsulated in ON-BOARD nanoparticles and characterized for particle properties. The formulations were assessed in vitro under neutral or acid-activated conditions in TDCC assays. In vivo studies were performed in mice bearing “immune desert” pancreatic cancer. ON-BOARD tumor localization was measured by fluorescence while unencapsulated TCE and ON-BOARD/TCE pharmacokinetics was evaluated. PD studies evaluated immune-phenotype changes in tumors and draining lymph nodes, and systemic cytokine levels. Efficacy studies were performed in tumor-bearing mice comparing unencapsulated TCE to ON-BOARD-TCE as monotherapy and in combination with anti-4-1BB agonist therapy. ON-BOARD encapsulated TCEs have high encapsulation efficiency (&amp;gt;88%) in uniformly distributed stable particles (Dh&amp;lt;100nm). pH-specific and target-specific killing were confirmed in vitro in TDCC killing assays using a human gastric cancer cell line and a genetically engineered mouse pancreatic cancer cell line with 20 to 200-fold activation window between the acid-activated and intact formulations. In vivo, fluorescently labeled ON-BOARD nanoparticles localized to tumors in mice while ON-BOARD/TCE formulations demonstrated minimal payload leakage and mitigated payload degradation. ON-BOARD/TCE formulations showed favorable immunophenotype changes in tumors including increased CD8+, CD8+/T reg ratio and PD-1+Ki67+CD8+. ON-BOARD encapsulation also significantly improved TCE tolerability showing reduced body weight loss nadir (3% vs 17%) and reduced systemic proinflammatory cytokine response (IL-6, TNF, IFNγ, etc). When dosed in combination with anti-4-1BB agonist therapy in tumor-bearing animals, unencapsulated TCE induced 100% treatment-related animal death while ON-BOARD/TCE prevented animal death with minimum body weight loss. Furthermore, ON-BOARD/TCE with a4-1BB combo therapy showed 61% tumor growth inhibition in the “immune desert” pancreatic cancer model. The ON-BOARD platform demonstrated potential as an effective tool for masked tumor-specific delivery and improved tolerability of bispecific TCEs for cancer therapy. Citation Format: Qingtai Su, Stephen Gutowski, Gaurav Bharadwaj, Austin Burcham, Bhargavi Allu, Irina Kalashnikova, Zirong Chen, Ruolan Han, Jason B. Miller, Tian Zhao. Improved tolerability and tumor specific delivery of a therapeutic bispecific T cell engager using a pH-sensitive nanoparticle platform [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 815.

Addressing safety concerns of long-term probiotic use: In vivo evidence from a rat model

The global market for probiotic supplements is continually expanding. However, the certainty of their safety is still a matter of concern. Since multi-strain probiotics are gaining increasing interest in clinical practice, the aim of the presented study was to evaluate the long-term effects of probiotic mixture on healthy Wistar rats with the focus on colon histology, haematology, serum biochemistry, inflammatory cytokine production and faecal microbiota composition. The long-term supplementation resulted in systemic pro-inflammatory response accompanied by increased abundance of bacterial families associated with the promotion of gastrointestinal inflammation. The important indicators of cardiovascular risk were significantly elevated after long-term probiotic treatment. Even though no histopathological lesions were detected in the colon, enlarged lymphoid aggregates and follicles were observed in probiotic-fed rats. Based on our study, commercially available probiotics for human use which are recommended as prophylaxis should be monitored for possible side effect after long-term usage. Our study thus contributes to the increasingly debated proposal of the scientific community which suggests the need to shift the future of probiotic prescription from the current ‘one-size-fits-all’ scheme into a person/condition-tailored approach with defined time of administration.

Renal Complications Following COVID-19 Vaccination: A Narrative Literature Review.

Renal complications have previously been reported with various vaccinations, including those for influenza and hepatitis. On a similar note, a spectrum of nephrological complications, both de novo, and flare-ups, were reported after immunization with various coronavirus disease 2019 (COVID-19) vaccines, causing concerns among patients as well as physicians. A systematic search of the literature published on renal complications seen post-COVID-19 vaccination was performed up to April 2022 using electronic databases such as PubMed and Google Scholar. Immunoglobulin A (IgA) nephropathy, minimal change disease, glomerulonephritis, acute kidney injury, nephrotic syndrome, and anti-neutrophil cytoplasmic antibody-associated vasculitis were some of the renal complications reported upon administration of COVID-19 vaccines. The causality and underlying pathogenic mechanisms linking these complications and COVID-19 vaccination remain unclear. Nonetheless, a temporal relationship has been established with dysregulated T-cell response, transient systemic pro-inflammatory cytokine response, molecular mimicry, delayed hypersensitivity reaction to the vaccine, and other mechanisms such as hyperresponsive IgA, dysregulation of neutrophil extracellular traps were hypothesized as the possible mechanisms linking renal complications and COVID-19 vaccination. This review emphasizes the need for rigorous surveillance and reporting of the adverse events following COVID-19 vaccination and explores the underlying mechanisms instigating these renal complications in individuals vaccinated against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Effects of Tea Tree Oil on Production Performance, Serum Parameter Indices, and Immunity in Postpartum Dairy Cows

Tea tree oil (TTO) plays an important role in regulating lipid metabolism and has anti-inflammatory properties. In postpartum dairy cows, dry matter intake (DMI) is dramatically decreased, resulting in lipid metabolism disorder and the systemic pro-inflammatory response. However, the effects of TTO on glucolipid metabolism and immunity in postpartum dairy cows remain uninvestigated. Therefore, this study aimed to evaluate the effects of TTO on production performance, serum biochemical indicators, and immunity in postpartum dairy cows. Our results demonstrate that DMI tended to increase (p = 0.07) in the total mixed ration (TMR) diets supplemented with 0.01% TTO/dry matter (DM) basis relative to that in the control group. The 4% fat-corrected milk (FCM) content in the 0.01% and 0.02% TTO groups showed an increase (p = 0.09) compared with that in the control. Remarkably, the levels of globulin (GLO) and immunoglobulin G (IgG) were elevated (p < 0.05) in the TMR diet supplemented with 0.02% TTO compared to those in the control group. The TTO caused no profound changes in cholesterol (CHO), triglyceride (TG), high-density lipoprotein (HDL), or low-density lipoprotein (LDL). Notably, 0.02% TTO increased (p < 0.05) the serum glucose concentration relative to that in the control group. In conclusion, our results demonstrate that TTO could improve glucolipid metabolism and enhance immunity in postpartum dairy cows. It may be a novel resolution strategy for body condition recovery and the improvement of milk performance.

Immunogenicity and protection against Mycobacterium avium with a heterologous RNA prime and protein boost vaccine regimen

Prophylactic efficacy of two different delivery platforms for vaccination against Mycobacterium avium (M. avium) were tested in this study; a subunit and an RNA-based vaccine. The vaccine antigen, ID91, includes four mycobacterial antigens: Rv3619, Rv2389, Rv3478, and Rv1886. We have shown that ID91+GLA-SE is effective against a clinical NTM isolate, M. avium 2–151 smt. Here, we extend these results and show that a heterologous prime/boost strategy with a repRNA-ID91 (replicon RNA) followed by protein ID91+GLA-SE boost is superior to the subunit protein vaccine given as a homologous prime/boost regimen. The repRNA-ID91/ID91+GLA-SE heterologous regimen elicited a higher polyfunctional CD4+ TH1 immune response when compared to the homologous protein prime/boost regimen. More significantly, among all the vaccine regimens tested only repRNA-ID91/ID91+GLA-SE induced IFN-γ and TNF-secreting CD8+ T cells. Furthermore, the repRNA-ID91/ID91+GLA-SE vaccine strategy elicited high systemic proinflammatory cytokine responses and induced strong ID91 and an Ag85B-specific humoral antibody response a pre- and post-challenge with M. avium 2–151 smt. Finally, while all prophylactic prime/boost vaccine regimens elicited a degree of protection in beige mice, the heterologous repRNA-ID91/ID91+GLA-SE vaccine regimen provided greater pulmonary protection than the homologous protein prime/boost regimen. These data indicate that a prophylactic heterologous repRNA-ID91/ID91+GLA-SE vaccine regimen augments immunogenicity and confers protection against M. avium.

NUCLEAR FACTOR-ERYTHROID-2-RELATED FACTOR REGULATES SYSTEMIC AND PULMONARY BARRIER FUNCTION AND IMMUNE PROGRAMMING AFTER BURN AND INHALATION INJURY.

Major burn injury is associated with systemic hyperinflammatory and oxidative stresses that encompass the wound, vascular, and pulmonary systems that contribute to complications and poor outcomes. These stresses are exacerbated if there is a combined burn and inhalation (B+I) injury, which leads to increases in morbidity and mortality. Nuclear factor-erythroid-2-related factor (NRF2) is a transcription factor that functions to maintain homeostasis during stress, in part by modulating inflammation and oxidative injury. We hypothesized that the NRF2-mediated homeostasis after burn alone and combined B-I injury is insufficient, but that pharmacological activation of the NRF2 pathway has the potential to reduce/reverse acute hyper inflammatory responses. We found that, after burn and B+I injury, Nrf2 -/- mice have higher mortality and exhibit greater pulmonary edema, vascular permeability, and exacerbated pulmonary and systemic proinflammatory responses compared with injured wild-type (WT) controls. Transcriptome analysis of lung tissue revealed specific Nrf2 -dependent dysregulated immune pathways after injury. In WT mice, we observed that B+I injury induces cytosolic, but not nuclear, accumulation of NRF2 protein in the lung microenvironment compared with sham-injured controls. Bardoxolone methyl (CDDO-Me)-containing microparticles (CDDO-MPs) were developed that allow for dilution in saline and stable release of CDDO-Me. When delivered intraperitoneally into mice 1 hour after B+I injury, CDDO-MPs significantly reduced mortality and cytokine dysfunction compared with untreated B-I animals. These data implicate the role of NRF2 regulation of pulmonary and systemic immune dysfunction after burn and B+I injury, and also a deficiency in controlling immune dysregulation. Selectively activating the NRF2 pathway may improve clinical outcomes in burn and B+I patients.

Attenuation of relapsing fever neuroborreliosis in mice by IL-17A blockade

Relapsing fever due to Borrelia hermsii is characterized by recurrent bacteremia episodes. However, infection of B. hermsii, if not treated early, can spread to various organs including the central nervous system (CNS). CNS disease manifestations are commonly referred to as relapsing fever neuroborreliosis (RFNB). In the mouse model of B. hermsii infection, we have previously shown that the development of RFNB requires innate immune cells as well as T cells. Here, we found that prior to the onset of RFNB, an increase in the systemic proinflammatory cytokine response followed by sustained levels of IP-10 concurrent with the CNS disease phase. RNA sequencing analysis of the spinal cord tissue during the disease phase revealed an association of the interleukin (IL)-17 signaling pathway in RFNB. To test a possible role for IL-17 in RFNB, we compared B. hermsii infection in wild-type and IL-17A-/- mice. Although the onset of bacteremia and protective anti-B. hermsii antibody responses occurred similarly, the blood-brain barrier permeability, proinflammatory cytokine levels, immune cell infiltration in the spinal cord, and RFNB manifestations were significantly diminished in IL-17A-/- mice compared to wild-type mice. Treatment of B. hermsii-infected wild-type mice with anti-IL-17A antibody ameliorated the severity of spinal cord inflammation, microglial cell activation, and RFNB. These data suggest that the IL-17 signaling pathway plays a major role in the pathogenesis of RFNB, and IL-17A blockade may be a therapeutic modality for controlling neuroborreliosis.

The problem of the use of interferons in the novel coronavirus disease COVID-19 (Coronaviridae: Coronavirinae: Betacoronavirus: Sarbecovirus)

By the end of 2021, about 200 studies on the effect of interferons (IFNs) on the incidence and course of the new coronavirus infection COVID-19 (Coronaviridae: Coronavirinae: Betacoronavirus: Sarbecovirus) have been reported worldwide, with the number of such studies steadily increasing. This review discusses the main issues of the use of IFN drugs in this disease. The literature search was carried out in the PubMed, Scopus, Cochrane Library, Web of Science, RSCI databases, as well as in the Google Scholar preprint database using the available search queries «MeSH for coronavirus», «SARS-CoV-2», «IFN drugs», and «COVID-19». Interferon therapy is indicated for early administration (within the first 5 days of patient admission) in cases of mild to moderate COVID-19 to take advantage of the narrow therapeutic window of IFNs action. Control and suppression of viral replication requires therapy with IFNs and other effective antiviral agents that inhibit the reproduction of SARS-CoV-2 and induce several interferon-stimulated genes (ISG). Type I IFNs (IFN-I) exhibit potent pro-inflammatory properties and activate a wide variety of different cell types that respond to IFNs stimulation and pathogen entry. IFN-III confer local mucosal antiviral immunity without inducing the strong systemic pro-inflammatory responses associated with IFN-I. The use of IFNs drugs in the therapy of new coronavirus infection requires a cautious and differentiated approach, because in severe cases they can aggravate viral pathogenesis by causing excessive intensity of inflammatory reactions. The unique biological properties of substances of this class allow us to consider them as therapeutic agents with significant potential for use in patients with COVID-19.

42 The Overt Pulmonary and Systemic Pro-inflammatory Response After Burn and Inhalation Injury Is Mtor Dependent

IntroductionSevere burn injury can lead to local and systemic activation of the innate immune system which can cause a dysfunctional and overt pro-inflammatory response, resulting in inflammatory complications and organ dysfunction. If there is an inhalation injury concomitant with burn, patients have a 3.6 times higher mortality rate and greater than 70% chance of developing secondary respiratory complications. Previous work has shown that the Mechanistic/ Mammalian Target of Rapamycin (mTOR) pathway is involved in signaling neutrophil activity in burn patients. Antagonists of mTOR stimulation represent possible immunomodulatory therapies. However, it is unclear if mTOR plays a role in the pulmonary distress seen after combined burn and smoke inhalation (B+I) injury. The goals of this study were to 1) characterize a novel mouse model of combined B+I injury and 2) investigate the role of mTOR in the pro-inflammatory response after B+I injury.MethodsWe built upon our pre-established 20% total body surface area cutaneous burn mouse model by adding smoke inhalation injury and treating mice with rapamycin, a mTOR-specific inhibitor. In brief, mice were anesthetized before receiving controlled B+I, burn only, or sham injury. After resuscitation, they were given morphinated water for 24 hours before euthanasia and tissue collection. RNA and whole cells were extracted from lung and spleen tissue for analysis by Nanostring and Flow Cytometry, respectively. Fluid within the lung (bronchoalveolar lavage, BAL) and peripheral blood plasma were collected for pro-inflammatory cytokine quantification via magnetic bead multiplex assays.ResultsWildtype female C57BL/6 mice that underwent B+I injury exhibited elevated levels of protein, macrophages, and neutrophils in the lung cavity compared to burn alone. In addition, 29 genes were significantly differentially expressed in the lung tissue after B+I, suggesting that inhalation elicits a unique response when compared to burn alone. In the peripheral blood, B+I mice have a >4 fold increase in IL6 and 3 fold increase in MCP-1 pro-inflammatory cytokine levels. When we examined the role of mTOR in B+I injury, we found that pre-emptive rapamycin treatment leads to a reduction in peripheral blood pro-inflammatory cytokine levels, namely MCP1, TNFa, IL10, and IL2, and an increase in pro-inflammatory cytokine IL2 in the lung cavity. Rapamycin significantly affected expression levels of 46 genes in the lung and 36 genes in the spleen, indicating an mTOR-dependent response to inhalation injury.ConclusionsIn conclusion, these data describe a valuable mouse model of B+I with inhalation-specific immune phenotypes and implicate mTOR in the inhalation-induced hyper pro-inflammatory response.

Inflammatory degranulation of the cardiac resident mast cells suppresses the pacemaking and affects activation pattern in the sinoatrial node

BackgroundMany bacterial and viral infections may cause sepsis or/and systemic or local proinflammatory responses that lead to life-threatening cardiovascular system failure. Severe bradycardia and/or bradyarrhythmias frequently accompany systemic inflammation and contribute to hemodynamic insufficiency. Markers for immunocompetent cells have been shown to be present in the tissue of the primary heart pacemaker, the sinoatrial node (SAN). However, the role of the resident cardiac immune cells in inflammation-induced bradycardia and SAN automaticity have still not been elucidated. Materials and methodsConfocal and bright field microscopy were used to identify toluidine blue-positive cells (TPC) in the SAN. Standard microelectrode technique and optical mapping were used to record action potentials (AP) and analyze activation pattern in the SAN tissue preparation from rats in presence of secretagogue C48/80. ResultsNumerous TPC, which exhibit toluidine-accumulating granules, typical for mast cells, are revealed in the SAN region of the right atrium. The activation and degranulation of the resident mast cells by C48/80 leads to biphasic changes of the pacemaker AP rate in the SAN – an initial acceleration is followed by rate reduction. The activation of the resident mast cells causes an increase of the primary activation area in the SAN that probably underlies the AP rate increase in response to C48/80. In addition, the application of C48/80 causes the primary/leading activation point migration in the SAN and AP rate decrease is probably mediated by the shift of the primary pacemaker site to the region surrounding the coronary sinus. Moreover, inexcitable zones and conduction blocks induced in the central SAN myocardium by C48/80 underlie the suppression of automaticity. ConclusionThe degranulation of resident mast cells affects the pacemaker cardiomyocytes’ ability to generate spontaneous AP in the SAN tissue and causes shift of the dominant pacemaker site. Therefore, the activation of the resident mast cells in the SAN can be considered as a new mechanism of inflammatory induced bradyarrhythmias.