Interleukin-10 aerosol reduces proinflammatory mediators in bronchoalveolar fluid of endotoxemic rat

Kinetics of pro- and anti-inflammatory spike-specific cellular immune responses in long-term care facility residents after COVID-19 mRNA primary and booster vaccination: a prospective longitudinal study in Japan

BACKGROUND

The magnitude and durability of cell-mediated immunity in older and severely frail individuals following coronavirus disease 2019 (COVID-19) vaccination remain unclear. A controlled immune response could be the key to preventing severe COVID-19; however, it is uncertain whether vaccination induces an anti-inflammatory cellular immune response. To address these issues, a 48-week-long prospective longitudinal study was conducted. A total of 106 infection-naive participants (57 long-term care facility [LTCF] residents [median age; 89.0 years], 28 outpatients [median age; 72.0 years], and 21 healthcare workers [median age; 51.0 years]) provided peripheral blood mononuclear cell (PBMC) samples for the assessment of spike-specific PBMC responses before primary vaccination, 24 weeks after primary vaccination, and three months after booster vaccination. Cellular immune responses to severe acute respiratory syndrome coronavirus 2 spike protein were examined by measuring interferon (IFN)-γ, tumor necrosis factor (TNF), interleukin (IL)-2, IL-4, IL-6, and IL-10 levels secreted from the spike protein peptide-stimulated PBMCs of participants.

RESULTS

LTCF residents exhibited significantly lower IFN-γ, TNF, IL-2, and IL-6 levels than healthcare workers after the primary vaccination. Booster vaccination increased IL-2 and IL-6 levels in LTCF residents comparable to those in healthcare workers, whereas IFN-γ and TNF levels in LTCF residents remained significantly lower than those in healthcare workers. IL-10 levels were not significantly different from the initial values after primary vaccination but increased significantly after booster vaccination in all subgroups. Multivariate analysis showed that age was negatively associated with IFN-γ, TNF, IL-2, and IL-6 levels but not with IL-10 levels. The levels of pro-inflammatory cytokines, including IFN-γ, TNF, IL-2, and IL-6, were positively correlated with humoral immune responses, whereas IL-10 levels were not.

CONCLUSIONS

Older and severely frail individuals may exhibit diminished spike-specific PBMC responses following COVID-19 vaccination compared to the general population. A single booster vaccination may not adequately enhance cell-mediated immunity in older and severely frail individuals to a level comparable to that in the general population. Furthermore, booster vaccination may induce not only a pro-inflammatory cellular immune response but also an anti-inflammatory cellular immune response, potentially mitigating detrimental hyperinflammation.

Inhibition of gp130 alleviates LPS-induced lung injury by attenuating apoptosis and inflammation through JAK1/STAT3 signaling pathway

BACKGROUND AND OBJECTIVE

Acute lung injury or acute respiratory distress syndrome (ALI/ARDS) is a life-threatening respiratory disease. Gp130 is a signal transduction receptor that participates in a variety of essential biological processes. The biological function of gp130 in ALI/ARDS is unclear. This study aims to investigate the roles and potential mechanisms of gp130 in lung injury induced by lipopolysaccharide (LPS).

METHODS

The ALI/ARDS mouse model was established using intratracheal LPS administration. Hematoxylin and eosin staining and bronchoalveolar lavage fluid analysis were used to evaluate the degree of lung injury. Cell apoptosis was assessed by TUNEL staining, flow cytometry, and western blot. Then the expression of gp130, IL-6, IL-10, TNF-α, and the JAK1/STAT3 signaling pathway-related proteins was assessed by RT-PCR, western blot, and immunohistochemistry.

RESULTS

The expression of gp130 increased after 24 h of LPS treatment. Inhibiting gp130 improved inflammatory infiltration and alveolar collapsed, decreased IL-6 and TNF-α levels, raised IL-10 levels, and decreased cell apoptosis in LPS-induced mice. Meanwhile, suppressing gp130 reduced the inflammatory response and cell apoptosis in LPS-induced Beas-2B cells. Furthermore, p-JAK1 and p-STAT3 expressions were elevated after LPS stimulation and decreased following gp130 inhibition, suggesting that gp130 may regulate the JAK1/STAT3 signaling pathway in LPS-induced mice and Beas-2B cells.

CONCLUSION

The findings suggest that gp130 regulates the inflammatory response and cell apoptosis through the JAK1/STAT3 signaling pathway, thereby mitigating LPS-induced lung injury. Gp130 may be a potential therapeutic target for ALI/ARDS.

Profiling serum levels of glutathione reductase and interleukin-10 in positive and negative-PCR COVID-19 outpatients: A comparative study from southwestern Iran

Since the outbreak of COVID-19 in China, it has rapidly spread across many other countries. We evaluated antioxidant defense systems and inflammatory status related to the SARS-CoV2 infection in a population from southwestern Iran. Comorbidities and clinical symptoms of 104 subjects (comprising negative and positive-PCR COVID-19 outpatients) were assessed. Serum concentrations of glutathione reductase (GR) and interleukin-10 (IL-10) were measured using ELISA. In the positive-PCR group, follow-ups on clinical symptoms were carried out for 28 days at 7-day intervals. In the positive-PCR group, hypertension, diabetes, liver disease, chronic heart disease, and chronic kidney disease were the most common comorbidities. In the general category of symptoms, we found a significant difference between negative and positive-PCR groups, except regarding runny noses. In the pulmonary category, there was a significant difference between the two groups except in terms of chest pain. We also determined a significant difference in neurologic symptoms, except for ear pain, between negative and positive-PCR groups. We also found significantly lower levels of GR but higher levels of IL-10 in the positive-PCR group (p = 0.000 for both). In the positive-PCR group, serum levels of IL-10 (odds ratio = 0.914, p = 0.012) decreased the chances of neurological symptoms occurring over time. The antioxidant defense systems of positive-PCR outpatients failed as demonstrated by a reduction in the serum levels of GR. We also indicated a dysregulation in the immune response against COVID-19, characterized by changes in serum IL-10 levels.

Lung Protection vs. Infection Resolution: Interleukin 10 Suspected of Double-Dealing in COVID-19

The pathological processes by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection that make the virus a major threat to global health are insufficiently understood. Inefficient viral clearance at any stage is a hallmark of coronavirus disease 2019 (COVID-19). Disease severity is associated with increases in peripheral blood cytokines among which interleukin 10 (IL-10) increases particularly early and independent of patient age, which is not seen in active SARS-CoV infection. Here, we consider the known multi-faceted immune regulatory role of IL-10, both in protecting the lung from injury and in defense against infections, as well as its potential cellular source. While the absence of an IL-10 response in SARS is thought to contribute to early deterioration, we suspect IL-10 to protect the lung from early immune-mediated damage and to interfere with viral clearance in COVID-19. This may further both viral spread and poor outcome in many high-risk patients. Identifying the features of the viral genotype, which specifically underlie the different IL-10 dynamics as an etiological endotype and the different viral load kinetics and outcomes as clinical phenotype, may unveil a new immune evasive strategy of SARS-CoV-2.

Melatonin receptor agonist protects against acute lung injury induced by ventilator through up-regulation of IL-10 production

Background

It is well known that ventilation with high volume or pressure may damage healthy lungs or worsen injured lungs. Melatonin has been reported to be effective in animal models of acute lung injury. Melatonin exerts its beneficial effects by acting as a direct antioxidant and via melatonin receptor activation. However, it is not clear whether melatonin receptor agonist has a protective effect in ventilator-induced lung injury (VILI). Therefore, in this study, we determined whether ramelteon (a melatonin receptor agonist) can attenuate VILI and explore the possible mechanism for protection.

Methods

VILI was induced by high tidal volume ventilation in a rat model. The rats were randomly allotted into the following groups: control, control+melatonin, control+ramelteon, control+luzindole, VILI, VILI+luzindole, VILI + melatonin, VILI + melatonin + luzindole (melatonin receptor antagonist), VILI + ramelteon, and VILI + ramelteon + luzindole (n = 6 per group). The role of interleukin-10 (IL-10) in the melatonin- or ramelteon-mediated protection against VILI was also investigated.

Results

Ramelteon treatment markedly reduced lung edema, serum malondialdehyde levels, the concentration of inflammatory cytokines in bronchoalveolar lavage fluid (BALF), NF-κB activation, iNOS levels, and apoptosis in the lung tissue. Additionally, ramelteon treatment significantly increased heat shock protein 70 expression in the lung tissue and IL-10 levels in BALF. The protective effect of ramelteon was mitigated by the administration of luzindole or an anti-IL-10 antibody.

Conclusions

Our results suggest that a melatonin receptor agonist has a protective effect against VILI, and its protective mechanism is based on the upregulation of IL-10 production.

Loss of myeloid-specific protein phosphatase 2A enhances lung injury and fibrosis and results in IL-10-dependent sensitization of epithelial cell apoptosis

Protein phosphatase 2A (PP2A), a ubiquitously expressed Ser/Thr phosphatase is an important regulator of cytokine signaling and cell function. We previously showed that myeloid-specific deletion of PP2A (LysM^crePP2A^-/-) increased mortality in a murine peritoneal sepsis model. In the current study, we assessed the role of myeloid PP2A in regulation of lung injury induced by lipopolysaccharide (LPS) or bleomycin delivered intratracheally. LysM^crePP2A^-/- mice experienced increased lung injury in response to both LPS and bleomycin. LysM^crePP2A^-/- mice developed more exuberant fibrosis in response to bleomycin, elevated cytokine responses, and chronic myeloid inflammation. Bone marrow-derived macrophages (BMDMs) from LysM^crePP2A^-/- mice showed exaggerated inflammatory cytokine release under conditions of both M1 and M2 activation. Notably, secretion of IL-10 was elevated under all stimulation conditions, including activation of BMDMs by multiple Toll-like receptor ligands. Supernatants collected from LPS-stimulated LysM^crePP2A^-/- BMDMs induced epithelial cell apoptosis in vitro but this effect was mitigated when IL-10 was also depleted from the BMDMs by crossing LysM^crePP2A^-/- mice with systemic IL-10^-/- mice (LysM^crePP2A^-/- × IL-10^-/-) or when IL-10 was neutralized. Despite these findings, IL-10 did not directly induce epithelial cell apoptosis but sensitized epithelial cells to other mediators from the BMDMs. Taken together our results demonstrate that myeloid PP2A regulates production of multiple cytokines but that its effect is most pronounced on IL-10 production. Furthermore, IL-10 sensitizes epithelial cells to apoptosis in response to myeloid-derived mediators, which likely contributes to the pathogenesis of lung injury and fibrosis in this model.

Fibrosis Related Inflammatory Mediators: Role of the IL-10 Cytokine Family

Importance of chronic fibroproliferative diseases (FDs) including pulmonary fibrosis, chronic kidney diseases, inflammatory bowel disease, and cardiovascular or liver fibrosis is rapidly increasing and they have become a major public health problem. According to some estimates about 45% of all deaths are attributed to FDs in the developed world. Independently of their etiology the common hallmark of FDs is chronic inflammation. Infiltrating immune cells, endothelial, epithelial, and other resident cells of the injured organ release an orchestra of inflammatory mediators, which stimulate the proliferation and excessive extracellular matrix (ECM) production of myofibroblasts, the effector cells of organ fibrosis. Abnormal amount of ECM disturbs the original organ architecture leading to the decline of function. Although our knowledge is rapidly expanding, we still have neither a diagnostic tool to detect nor a drug to specifically target fibrosis. Therefore, there is an urgent need for the more comprehensive understanding of the pathomechanism of fibrosis and development of novel diagnostic and therapeutic strategies. In the present review we provide an overview of the common key mediators of organ fibrosis highlighting the role of interleukin-10 (IL-10) cytokine family members (IL-10, IL-19, IL-20, IL-22, IL-24, and IL-26), which recently came into focus as tissue remodeling-related inflammatory cytokines.

Pro-Inflammatory Signaling by IL-10 and IL-22: Bad Habit Stirred Up by Interferons?

Interleukin (IL)-10 and IL-22 are key members of the IL-10 cytokine family that share characteristic properties such as defined structural features, usage of IL-10R2 as one receptor chain, and activation of signal transducer and activator of transcription (STAT)-3 as dominant signaling mode. IL-10, formerly known as cytokine synthesis inhibitory factor, is key to deactivation of monocytes/macrophages and dendritic cells. Accordingly, pre-clinical studies document its anti-inflammatory capacity. However, the outcome of clinical trials assessing the therapeutic potential of IL-10 in prototypic inflammatory disorders has been disappointing. In contrast to IL-10, IL-22 acts primarily on non-leukocytic cells, in particular epithelial cells of intestine, skin, liver, and lung. STAT3-driven proliferation, anti-apoptosis, and anti-microbial tissue protection is regarded a principal function of IL-22 at host/environment interfaces. In this hypothesis article, hidden/underappreciated pro-inflammatory characteristics of IL-10 and IL-22 are outlined and related to cellular priming by type I interferon. It is tempting to speculate that an inherent inflammatory potential of IL-10 and IL-22 confines their usage in tissue protective therapy and beyond that determines in some patients efficacy of type I interferon treatment.

Inhalative vs. systemic IL-10 administration: differences in the systemic inflammatory response and end-organ inflammation following hemorrhagic shock

Interleukin-10 is known to modulate the systemic inflammatory response after trauma. This study investigates differences in the systemic and end-organ inflammation in animals treated with either inhalative or systemic IL-10 after experimental hemorrhagic shock (HS). Pressure controlled HS was performed in C57/BL6 mice for 1.5h (6 animals per group). Inhalative or systemic recombinant mouse IL-10 (50 μg/kg dissolved in 50 μl PBS) was administered after resuscitation. Animals were sacrificed after 4.5 or 22.5h of recovery. Serum levels of IL-6, IL-10, KC, MCP-1, and LBP were determined by ELISA. Pulmonary and liver inflammation was analyzed by standardized Myeloperoxidase (MPO) kits. Systemic and inhalative IL-10 administration affected the systemic inflammatory response as well as end-organ inflammation differently. Differences were obvious in the early (6h) but not later (24h) inflammatory phase. Systemic IL-10 application was associated with a decreased systemic inflammatory response as well as hepatic inflammation, whereas nebulized IL-10 solely reduced the pulmonary inflammation. Our study demonstrates that systemic and nebulized IL-10 administration differentially influenced the systemic cytokine response and end-organ inflammation. Early pulmonary but not hepatic protection appears to be possible by inhalative IL-10 application. Further studies are necessary to assess exact pathways.

Urinary trypsin inhibitor attenuates lipopolysaccharide-induced acute lung injury by blocking the activation of p38 mitogen-activated protein kinase

OBJECTIVE

To investigate the protective effect of urinary trypsin inhibitor (UTI) in a rat model of lipopolysaccharide (LPS)-induced acute lung injury (ALI) and the underlying molecular mechanism.

METHODS

Rats were randomly assigned into three groups: control group, LPS treatment group and LPS/UTI treatment group. The serum concentrations of tumor necrosis factor (TNF)-α and interleukin (IL)-10 were measured by ELISA. The expression of p38 mitogen-activated protein kinase (MAPK) in lung tissues was determined by Western blot analysis.

RESULTS

Administration of UTI reduced the lung wet/dry weight ratio and ameliorated the tissue damage. In the LPS/UTI treatment group, levels of TNF-α were significantly lower than those in the LPS treatment group, while the levels of IL-10 were significantly higher than those in the LPS treatment group. Western blot analysis revealed that UTI inhibited the phosphorylation of p38 MAPK in lung tissues.

CONCLUSIONS

UTI attenuates LPS-induced ALI, probably by adjusting the balance between proinflammatory and anti-inflammatory cytokines. The mechanism responsible for the decreased TNF-α expression may be related to the inhibitory effect of UTI on p38 MAPK activation.

Immunological response to (1,4)-alpha-D-glucan in the lung and spleen of endotoxin-stimulated juvenile rats

We investigated the effects of (1,4)-alpha-D-glucan (alpha-DG), a novel immune stimulatory drug from Tinospora cordifolia, on the concentration of pro- and anti-inflammatory cytokines (interleukin [IL]-1beta, IL-6, tumour necrosis factor-alpha [TNF-alpha], gamma-interferon [IFN-gamma] and IL-10) in the lung and spleen of endotoxin-stimulated juvenile rats. Experimental groups (n = 16/group) included controls with an intraperitoneal injection of saline, endotoxaemic rats with a non-lethal dose of 10 mg/kg Escherichia coli endotoxin, and endotoxaemic rats treated with two doses of 10 mg/kg alpha-DG, intraperitoneally, 2 and 4 hr after endotoxin injection. At 24 hr of treatment, rats were euthanized and lungs and spleen were removed for cytokines determination and lung injury. Endotoxaemia increased IL-1beta concentration by fivefold in both organs, while creating a moderate pulmonary hypercellularity (demonstrated by about 11% increase in the alveolar-septal thickening and 11% decrease in the alveolar-interstitial space ratio). In the lung, alpha-DG treatment reduced concentrations of IL-1beta by 30% (p > 0.05), IL-6 by 43% (p < 0.01), IFN-gamma by 46% (p < 0.01) and the anti-inflammatory cytokine, IL-10, by 31% (p > 0.05) compared to endotoxaemia. In the spleen, alpha-DG treatment decreased the ratio of IL-1beta to IL-10 by 55% (p < 0.05), demonstrating an anti-inflammatory trend. These data suggest that alpha-DG differentially modulates cytokine response in the lung and spleen and modifies the pro- and anti-inflammatory balance during an early period of endotoxaemia in juvenile rats.

Attenuation of lipopolysaccharide-induced acute lung injury by treatment with IL-10

BACKGROUND AND OBJECTIVE

The aim of this study was to characterize the changes in neutrophils and cytokines in BAL fluid following acute lung injury (ALI), and to determine the protective effect of post-injury treatment with IL-10.

METHODS

A rat model of ALI was established by evenly spraying LPS (16 mg/kg) into the lungs followed by observation for 48 h. Histological changes and the kinetics of neutrophil infiltration were evaluated in the injured lungs. The cytokines (TNF-alpha, IL-6, IL-10 and interferon-gamma) and macrophage-inflammatory protein (MIP-2) were measured in BAL fluid by ELISA. The activation of BAL fluid neutrophils was investigated after treatment with IL-10 in vitro. The protective effect on histology and MIP-2 levels of intra-tracheal instillation of IL-10 12 and 16 h after LPS treatment was studied in vivo.

RESULTS

Intra-tracheal instillation of LPS caused significant lung injury and the activation of neutrophils. The levels of TNF-alpha and IL-6 in BAL fluid peaked at 8 and 16 h after LPS instillation respectively. IL-10 levels reached a maximum at 16-24 h, at the beginning of resolution of tissue injury. IL-10 inhibited the activation of neutrophils in vitro and MIP-2 induction in vivo. IL-10 had a protective effect if it was administered 12 but not 16 h after LPS.

CONCLUSIONS

Neutrophils appeared to play an important role in ALI. Time-dependent treatment with IL-10 after intra-tracheal instillation of LPS was effective in protecting rats from ALI, probably by suppressing pulmonary infiltration with activated neutrophils.

Inhaled IL-10 reduces biotrauma and mortality in a model of ventilator-induced lung injury

BACKGROUND

High-pressure ventilation induces barotrauma and pulmonary inflammation, thus leading to ventilator-induced lung injury (VILI). By limiting the pulmonal inflammation cascade the anti-inflammatory cytokine interleukin (IL)-10 may have protective effects. Via inhalation, IL-10 reaches the pulmonary system directly and in high concentrations.

METHODS

Thirty six male, anesthetized and mechanically ventilated Sprague-Dawley rats were randomly assigned to the following groups (n=9, each): SHAM: pressure controlled ventilation with p(max)=20cmH(2)O, PEEP=4; VILI: ventilator settings were changed for 20min to p(max)=45cmH(2)O, PEEP=0; IL-10(high): inhalation of 10microg/kg IL-10 prior to induction of VILI; and IL-10(low): inhalation of 1microg/kg IL-10 prior to induction of VILI. All groups were ventilated and observed for 4h.

RESULTS

High-pressure ventilation increased the concentrations of macrophage inflammatory protein (MIP)-2 and IL-1beta in bronchoalveolar lavage fluid (BALF) and plasma. This effect was reduced by the inhalation of IL-10 (10microg/kg). Additionally, IL-10 increased the animal survival time (78% vs. 22% 4-h mortality rate) and reduced NO-release from ex vivo cultured alveolar macrophages. Moreover, VILI-induced pulmonary heat shock protein-70 expression was reduced by IL-10 aerosol in a dose-dependent manner. Similarly, the activation of matrix metalloproteinase (MMP)-9 in BALF was reduced dose-dependently by IL-10. IL-10-treated animals showed a lower macroscopic lung injury score and less impairment of lung integrity and gas exchange.

CONCLUSIONS

Prophylactic inhalation of IL-10 improved survival and reduced lung injury in experimental VILI. Results indicate that this effect may be mediated by the inhibition of stress-induced inflammation and pulmonary biotrauma.

Targeting caspase-1 by inhalation-therapy: effects of Ac-YVAD-CHO on IL-1 beta, IL-18 and downstream proinflammatory parameters as detected in rat endotoxaemia

OBJECTIVE

We set out to investigate whether the nebulized and inhaled specific caspase-1 inhibitor Ac-YVAD-CHO has the potential to attenuate the pulmonary and systemic release of the caspase-1-dependent cytokines interleukin-1 beta (IL-1 beta) and interleukin-18 (IL-18) as well as their downstream enzymes iNOS and COX-2 in rat experimental endotoxaemia.

DESIGN AND SETTING

Controlled, randomized animal study in a university research facility.

SUBJECT

Male Sprague-Dawley rats (n=32) were randomly treated as follows: Inhaled Ac-YVAD-CHO was administered in eight rats at a inhaled total dosage of 5 mg and in eight rats at a inhaled total dose of 0.5 mg before infusion of lipopolysaccharide (LPS; 5 mg/kg, i.v.). Eight animals received LPS only. Eight animals served as controls without endotoxaemia.

MEASUREMENTS AND RESULTS

After 4h of endotoxaemia, levels of IL-1 beta, IL-18 and TNF-alpha in plasma and bronchoalveolar fluid (BALF) were analyzed. Nitric oxide (NO) release from alveolar macrophages was measured by Griess assay. Amounts of iNOS protein in alveolar macrophages and COX-2 protein in lung homogenates were determined by Western blotting. Significant reductions in release of IL-1 beta (-58%, p<0.05) and IL-18 (-51%, p<0.05) in plasma and IL-1 beta (-59%, p<0.05) in BALF were found in animals pretreated with inhaled caspase-1 inhibitor compared with animals without therapy. Expression of iNOS in alveolar macrophages and COX-2 in lung tissue was concurrently decreased in the treatment groups compared with control animals.

CONCLUSIONS

Our data demonstrate that administration of the caspase-1 inhibitor Ac-YVAD-CHO by inhalation is able to reduce the pulmonary and systemic release of proinflammatory mediators in rat endotoxaemia. These results further underscore that inhalation may constitute an effective route of anti-inflammatory drug administration, beneficial in the clinical setting of ARDS.

Modulation of endotoxin-induced neutrophil transendothelial migration by alveolar epithelium in a defined bilayer model

Within the alveolus, epithelial cells, due to their close association with endothelial cells, can potentially influence endothelial cell responsiveness during inflammation and their interaction with leukocytes. To investigate this, three lung epithelial cell lines (A549, Calu-3, or NCI-H441) were grown with endothelium on opposing surfaces of Transwell filters and the formation and stability of bilayers was rigorously evaluated. All epithelial lines disrupted endothelial monolayer formation on filters with 3- or 5-microm pores by breaching the filter, and this occurred regardless of seeding density, matrix composition, or duration of culture. Endothelial disruption was not detectable by electrical resistance or permeability measurements but required cell-specific staining with immunofluorescence and microscopy. Distinct bilayers formed only on filters with 0.4-microm pores and only with A549 cells and human umbilical vein endothelial cells. Endotoxin (lipopolysaccharide [LPS]) stimulation of bilayers (4 hours) enhanced neutrophil transendothelial migration, but this was significantly decreased compared with the response of endothelium grown alone, irrespective of whether LPS exposure was via the epithelial or endothelial side of the bilayer. Down-modulation required epithelial-endothelial approximation and was not seen when these cells were separated by 0.5 to 1 mm. This study defines optimal conditions required for generation of intact bilayers of lung epithelial cells with endothelium for the study of leukocyte-transendothelial migration. Furthermore, it was demonstrated that lung epithelial cells can modulate endothelial cell responsiveness to an environmental inflammatory stimulus such as LPS and thus may have an important role in minimizing excessive and deleterious neutrophilic inflammation in the lung alveolus.