IL10 deficiency promotes alveolar enlargement and lymphoid dysmorphogenesis in the aged murine lung

MMP-12 and Periodontitis: Unraveling the Molecular Pathways of Periodontal Tissue Destruction

Periodontal disease is a common disorder affecting a wide range of people and has a high prevalence globally. Periodontitis comprises a series of inflammatory conditions affecting periodontal support tissue, which could ultimately lead to tooth loss and reduce life quality and add to the financial burden of society. Matrix metalloproteinase-12 (MMP-12) is an elastase that is produced mostly by macrophages and could degrade a wide spectrum of extracellular matrix (ECM) and also contribute to several systematic pathological conditions. Recently, researchers have reported higher expression of MMP-12 in chronic periodontitis patients. However, there are few reports on the role of MMP-12 in periodontitis pathogenicity, and the interaction between MMP-12, periodontal pathogens, and periodontal tissues remains unclear. In this review, we introduce the potentially unique role of MMP-12 in the context of periodontal inflammation earlier, summarize the possible effects of MMP-12 on the pathological process of periodontitis and the interaction of host response under the challenge of various inflammatory factors, and provide possible diagnostic and therapeutic strategies targeting MMP-12 for the management of periodontitis. Future research and policies should focus on and implement effective chairside testing methods to reduce the prevalence of periodontal diseases.

IL-10 deficiency aggravates cell senescence and accelerates BLM-induced pulmonary fibrosis in aged mice via PTEN/AKT/ERK pathway

BACKGROUND

Pulmonary fibrosis (PF) is an aging-related progressive lung disorder. The aged lung undergoes functional and structural changes termed immunosenescence and inflammaging, which facilitate the occurrence of fibrosis. Interleukin-10 (IL-10) is a potent anti-inflammatory and immunoregulatory cytokine, yet it remains unclear how IL-10 deficiency-induced immunosenescence participates in the development of PF.

METHODS

Firstly we evaluated the susceptibility to fibrosis and IL-10 expression in aged mice. Then 13-month-old wild-type (WT) and IL-10 knockout (KO) mice were subjected to bleomycin(BLM) and analyzed senescence-related markers by PCR, western blot and immunohistochemistry staining of p16, p21, p53, as well as DHE and SA-β-gal staining. We further compared 18-month-old WT mice with 13-month-old IL-10KO mice to assess aging-associated cell senescence and inflamation infiltration in both lung and BALF. Moreover, proliferation and apoptosis of alveolar type 2 cells(AT2) were evaluated by FCM, immunofluorescence, TUNEL staining, and TEM analysis. Recombinant IL-10 (rIL-10) was also administered intratracheally to evaluate its therapeutic potential and related mechanism. For the in vitro experiments, 10-week-old naïve pramily lung fibroblasts(PLFs) were treated with the culture medium of 13-month PLFs derived from WT, IL-10KO, or IL-10KO + rIL-10 respectively, and examined the secretion of senescence-associated secretory phenotype (SASP) factors and related pathways.

RESULTS

The aged mice displayed increased susceptibility to fibrosis and decreased IL-10 expression. The 13-month-old IL-10KO mice exhibited significant exacerbation of cell senescence compared to their contemporary WT mice, and even more severe epithelial-mesenchymal transition (EMT) than that of 18 month WT mice. These IL-10 deficient mice showed heightened inflammatory responses and accelerated PF progression. Intratracheal administration of rIL-10 reduced lung CD45 + cell infiltration by 15%, including a 6% reduction in granulocytes and a 10% reduction in macrophages, and increased the proportion of AT2 cells by approximately 8%. Additionally, rIL-10 significantly decreased α-SMA and collagen deposition, and reduced the expression of senescence proteins p16 and p21 by 50% in these mice. In vitro analysis revealed that conditioned media from IL-10 deficient mice promoted SASP secretion and upregulated senescence genes in naïve lung fibroblasts, which was mitigated by rIL-10 treatment. Mechanistically, rIL-10 inhibited TGF-β-Smad2/3 and PTEN/PI3K/AKT/ERK pathways, thereby suppressing senescence and fibrosis-related proteins.

CONCLUSIONS

IL-10 deficiency in aged mice leads to accelerated cell senescence and exacerbated fibrosis, with IL-10KO-PLFs displaying increased SASP secretion. Recombinant IL-10 treatment effectively mitigates these effects, suggesting its potential as a therapeutic target for PF.

The Effects of High-Fat Diet and Flaxseed Oil-Enriched Diet on the Lung Parenchyma of Obese Mice

Omega-3 (ω3) fatty acids are widely investigated for their anti-inflammatory potential, however, there is little evidence regarding their action in the lung parenchyma in the context of obesity. The objective is to investigate the effects of flaxseed oil (FS), rich in α-linolenic (C18:3 - ω3), on the lungs of obese mice. Mice were fed a high-fat diet (HF) for 8 weeks to induce obesity. Subsequently, a part of these animals received HF containing FS oil for another 8 weeks. The HF consumption induced weight gain and hyperglycemia. The lung parenchyma shows a complete fatty acids profile, compared to the control group (CT). In the lung parenchyma, FS increases the ω3 content and, notwithstanding a reduction in the interleukins (IL) IL1β and IL18 contents compared to HF. However, FS promoted increased alveolar spaces, followed by MCP1 (Monocytes Chemoattractant Protein-1) positive cell infiltration and a dramatic reduction in the anti-inflammatory cytokine, IL10. Despite reducing the pulmonary inflammatory response, the consumption of a food source of ω3 was associated with alterations in the lipid profile and histoarchitecture of the lung parenchyma, which can lead to the development of pulmonary complications. This study brings an alert against the indiscriminate use of ω3 supplements, warranting caution.

Unlocking the protective potential of the angiotensin type 2 receptor (AT2R) in acute lung injury and age-related pulmonary dysfunction

Despite its known importance in the cardiovascular system, the specific role and impact of the angiotensin type 2 receptor (AT2R) in lung physiology and pathophysiology remain largely elusive. In this study, we highlight the distinct and specialized lung-specific roles of AT2R, primarily localized to an alveolar fibroblast subpopulation, in contrast to the angiotensin type 1 receptor (AT1R), which is almost exclusively expressed in lung pericytes. Evidence from our research demonstrates that the disruption of AT2R (AT2R-/y), is associated with a surge in oxidative stress and impaired lung permeability, which were further intensified by Hyperoxic Acute Lung Injury (HALI). With aging, AT2R-/y mice show an increase in oxidative stress, premature enlargement of airspaces, as well as increased mortality when exposed to hyperoxia as compared to age-matched WT mice. Our investigation into Losartan, an AT1R blocker, suggests that its primary HALI lung-protective effects are channeled through AT2R, as its protective benefits are absent in AT2R-/y mice. Importantly, a non-peptide AT2R agonist, Compound 21 (C21), successfully reverses lung oxidative stress and TGFβ activation in wild-type (WT) mice exposed to HALI. These findings suggest a possible paradigm shift in the therapeutic approach for lung injury and age-associated pulmonary dysfunction, from targeting AT1R with angiotensin receptor blockers (ARBs) towards boosting the protective function of AT2R.

Neutrophil responsiveness to IL-10 impairs clearance of Streptococcus pneumoniae from the lungs

The early immune response to bacterial pneumonia requires a careful balance between pathogen clearance and tissue damage. The anti-inflammatory cytokine interleukin (IL)-10 is critical for restraining otherwise lethal pulmonary inflammation. However, pathogen-induced IL-10 is associated with bacterial persistence in the lungs. In this study, we used mice with myeloid cell specific deletion of IL-10R to investigate the cellular targets of IL-10 immune suppression during infection with Streptococcus pneumoniae, the most common bacterial cause of pneumonia. Our findings suggest that IL-10 restricts the neutrophil response to S. pneumoniae, as neutrophil recruitment to the lungs was elevated in myeloid IL-10 receptor (IL-10R)-deficient mice and neutrophils in the lungs of these mice were more effective at killing S. pneumoniae. Improved killing of S. pneumoniae was associated with increased production of reactive oxygen species and serine protease activity in IL-10R-deficient neutrophils. Similarly, IL-10 suppressed the ability of human neutrophils to kill S. pneumoniae. Burdens of S. pneumoniae were lower in myeloid IL-10R-deficient mice compared with wild-type mice, and adoptive transfer of IL-10R-deficient neutrophils into wild-type mice significantly improved pathogen clearance. Despite the potential for neutrophils to contribute to tissue damage, lung pathology scores were similar between genotypes. This contrasts with total IL-10 deficiency, which is associated with increased immunopathology during S. pneumoniae infection. Together, these findings identify neutrophils as a critical target of S. pneumoniae-induced immune suppression and highlight myeloid IL-10R abrogation as a mechanism to selectively reduce pathogen burdens without exacerbating pulmonary damage.

Native lamin A/C proteomes and novel partners from heart and skeletal muscle in a mouse chronic inflammation model of human frailty

Clinical frailty affects ∼10% of people over age 65 and is studied in a chronically inflamed (Interleukin-10 knockout; "IL10-KO") mouse model. Frailty phenotypes overlap the spectrum of diseases ("laminopathies") caused by mutations in LMNA. LMNA encodes nuclear intermediate filament proteins lamin A and lamin C ("lamin A/C"), important for tissue-specific signaling, metabolism and chromatin regulation. We hypothesized that wildtype lamin A/C associations with tissue-specific partners are perturbed by chronic inflammation, potentially contributing to dysfunction in frailty. To test this idea we immunoprecipitated native lamin A/C and associated proteins from skeletal muscle, hearts and brains of old (21-22 months) IL10-KO versus control C57Bl/6 female mice, and labeled with Tandem Mass Tags for identification and quantitation by mass spectrometry. We identified 502 candidate lamin-binding proteins from skeletal muscle, and 340 from heart, including 62 proteins identified in both tissues. Candidates included frailty phenotype-relevant proteins Perm1 and Fam210a, and nuclear membrane protein Tmem38a, required for muscle-specific genome organization. These and most other candidates were unaffected by IL10-KO, but still important as potential lamin A/C-binding proteins in native heart or muscle. A subset of candidates (21 in skeletal muscle, 30 in heart) showed significantly different lamin A/C-association in an IL10-KO tissue (p < 0.05), including AldoA and Gins3 affected in heart, and Lmcd1 and Fabp4 affected in skeletal muscle. To screen for binding, eleven candidates plus prelamin A and emerin controls were arrayed as synthetic 20-mer peptides (7-residue stagger) and incubated with recombinant purified lamin A "tail" residues 385-646 under relatively stringent conditions. We detected strong lamin A binding to peptides solvent exposed in Lmcd1, AldoA, Perm1, and Tmem38a, and plausible binding to Csrp3 (muscle LIM protein). These results validated both proteomes as sources for native lamin A/C-binding proteins in heart and muscle, identified four candidate genes for Emery-Dreifuss muscular dystrophy (CSRP3, LMCD1, ALDOA, and PERM1), support a lamin A-interactive molecular role for Tmem38A, and supported the hypothesis that lamin A/C interactions with at least two partners (AldoA in heart, transcription factor Lmcd1 in muscle) are altered in the IL10-KO model of frailty.

Nebulized caffeine alleviates airway hyperresponsiveness in a murine asthma model

The clinical definition of "difficult asthma" has expanded recently to include an ever-growing subset of patients with symptoms that cannot be controlled by conventional means, forcing the medical community to develop innovative therapeutics. Beneficial effects of coffee for subjects with asthma, primarily the effect of methylxanthine components, have long been described. Methylxanthines, including theophylline and caffeine, inhibit phosphodiesterases and downstream cAMP signaling to prevent mast cell degranulation while promoting immunomodulation (Peleman RA, Kips JC, Pauwels RA. Clin Exp Allergy 28: 53-56, 1998; Deshpande DA, Wang WCH, McIlmoyle EL, Robinett KS, Schillinger RM, An SS, Sham JSK, Liggett SB. Nat Med 16: 1299-1304, 2010). Caffeine is also a bitter taste receptor agonist, binding to taste-sensing type 2 receptors (TAS2R) before releasing calcium to hyperpolarize airway smooth muscle membranes, inducing bronchodilation (Workman AD, Palmer JN, Adappa ND, Cohen NA. Curr Allergy Asthma Rep 15: 72, 2015; Devillier P, Naline E, Grassin-Delyle S. Pharmacol Ther 155: 11-21, 2015). Theophylline is conventionally used to treat asthma, whereas, according to the literature, the dosage required for orally administered caffeine has yielded modest improvement (Alfaro TM, Monteiro RA, Cunha RA, Cordeiro CR. Clin Respir J 12: 1283-1294, 2018). We sought to determine whether aerosolization of ultrafine caffeine particles (2.5-4 μm) directly to the lungs of susceptible A/J mice challenged with methacholine would improve pulmonary function via forced oscillation technique. In addition, we assessed whether nebulization of caffeine leads to changes in lung pathophysiology and bronchoalveolar lavage cell profiles. We found that mice that received aerosolized caffeine had statistically significant decreases in maximum airway resistance [6.3 vs. 3.9 cmH2O·s/mL at 62.5 mg/mL caffeine; confidence interval (CI) = -4.3, -0.4; P = 0.02] and significant delays in the time required to reach maximum resistance compared with that of controls (64.7 vs. 172.1 sec at 62.5 mg/mL caffeine, CI = 96.0, 118.9; P < 0.0001). Nebulized caffeine yielded a consistent effect on airway hyperresponsiveness at a range of doses without evidence of significant pathology relative to vehicle control.NEW & NOTEWORTHY For decades, coffee has been shown to improve symptoms in patients with asthma. One component, theophylline, is conventionally used to treat asthma, whereas the dosage required for orally administered caffeine has yielded modest improvement. We sought to determine whether aerosolization of caffeine directly to the lungs of susceptible A/J mice challenged with methacholine would alter pulmonary function via forced oscillation technique. We found nebulized caffeine yielded a consistent improvement on murine AHR.

Immunosenescence: A Critical Factor Associated With Organ Injury After Sepsis

Progressive immune dysfunction associated with aging is known as immunosenescence. The age-related deterioration of immune function is accompanied by chronic inflammation and microenvironment changes. Immunosenescence can affect both innate and acquired immunity. Sepsis is a systemic inflammatory response that affects parenchymal organs, such as the respiratory system, cardiovascular system, liver, urinary system, and central nervous system, according to the sequential organ failure assessment (SOFA). The initial immune response is characterized by an excess release of inflammatory factors, followed by persistent immune paralysis. Moreover, immunosenescence was found to complement the severity of the immune disorder following sepsis. Furthermore, the immune characteristics associated with sepsis include lymphocytopenia, thymus degeneration, and immunosuppressive cell proliferation, which are very similar to the characteristics of immunosenescence. Therefore, an in-depth understanding of immunosenescence after sepsis and its subsequent effects on the organs may contribute to the development of promising therapeutic strategies. This paper focuses on the characteristics of immunosenescence after sepsis and rigorously analyzes the possible underlying mechanism of action. Based on several recent studies, we summarized the relationship between immunosenescence and sepsis-related organs. We believe that the association between immunosenescence and parenchymal organs might be able to explain the delayed consequences associated with sepsis.

IL-10 and class 1 histone deacetylases act synergistically and independently on the secretion of proinflammatory mediators in alveolar macrophages

Introduction

Anti-inflammatory cytokine IL-10 suppresses pro-inflammatory IL-12b expression after Lipopolysaccharide (LPS) stimulation in colonic macrophages, as part of the innate immunity Toll-Like Receptor (TLR)-NF-κB activation system. This homeostatic mechanism limits excess inflammation in the intestinal mucosa, as it constantly interacts with the gut flora. This effect is reversed with Histone Deacetylase 3 (HDAC3), a class I HDAC, siRNA, suggesting it is mediated through HDAC3. Given alveolar macrophages’ prominent role in Acute Lung Injury (ALI), we aim to determine whether a similar regulatory mechanism exists in the typically sterile pulmonary microenvironment.

Methods

Levels of mRNA and protein for IL-10, and IL-12b were determined by qPCR and ELISA/Western Blot respectively in naïve and LPS-stimulated alveolar macrophages. Expression of the NF-κB intermediaries was also similarly assessed. Experiments were repeated with AS101 (an IL-10 protein synthesis inhibitor), MS-275 (a selective class 1 HDAC inhibitor), or both.

Results

LPS stimulation upregulated all proinflammatory mediators assayed in this study. In the presence of LPS, inhibition of IL-10 and/or class 1 HDACs resulted in both synergistic and independent effects on these signaling molecules. Quantitative reverse-transcriptase PCR on key components of the TLR4 signaling cascade demonstrated significant diversity in IL-10 and related gene expression in the presence of LPS. Inhibition of IL-10 secretion and/or class 1 HDACs in the presence of LPS independently affected the transcription of MyD88, IRAK1, Rela and the NF-κB p50 subunit. Interestingly, by quantitative ELISA inhibition of IL-10 secretion and/or class 1 HDACs in the presence of LPS independently affected the secretion of not only IL-10, IL-12b, and TNFα, but also proinflammatory mediators CXCL2, IL-6, and MIF. These results suggest that IL-10 and class 1 HDAC activity regulate both independent and synergistic mechanisms of proinflammatory cytokine/chemokine signaling.

Conclusions

Alveolar macrophages after inflammatory stimulation upregulate both IL-10 and IL-12b production, in a highly class 1 HDAC-dependent manner. Class 1 HDACs appear to help maintain the balance between the pro- and anti-inflammatory IL-12b and IL-10 respectively. Class 1 HDACs may be considered as targets for the macrophage-initiated pulmonary inflammation in ALI in a preclinical setting.

Identified GNGT1 and NMU as Combined Diagnosis Biomarker of Non-Small-Cell Lung Cancer Utilizing Bioinformatics and Logistic Regression

Non-small-cell lung cancer (NSCLC) is one of the most devastating diseases worldwide. The study is aimed at identifying reliable prognostic biomarkers and to improve understanding of cancer initiation and progression mechanisms. RNA-Seq data were downloaded from The Cancer Genome Atlas (TCGA) database. Subsequently, comprehensive bioinformatics analysis incorporating gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and the protein-protein interaction (PPI) network was conducted to identify differentially expressed genes (DEGs) closely associated with NSCLC. Eight hub genes were screened out using Molecular Complex Detection (MCODE) and cytoHubba. The prognostic and diagnostic values of the hub genes were further confirmed by survival analysis and receiver operating characteristic (ROC) curve analysis. Hub genes were validated by other datasets, such as the Oncomine, Human Protein Atlas, and cBioPortal databases. Ultimately, logistic regression analysis was conducted to evaluate the diagnostic potential of the two identified biomarkers. Screening removed 1,411 DEGs, including 1,362 upregulated and 49 downregulated genes. Pathway enrichment analysis of the DEGs examined the Ras signaling pathway, alcoholism, and other factors. Ultimately, eight prioritized genes (GNGT1, GNG4, NMU, GCG, TAC1, GAST, GCGR1, and NPSR1) were identified as hub genes. High hub gene expression was significantly associated with worse overall survival in patients with NSCLC. The ROC curves showed that these hub genes had diagnostic value. The mRNA expressions of GNGT1 and NMU were low in the Oncomine database. Their protein expressions and genetic alterations were also revealed. Finally, logistic regression analysis indicated that combining the two biomarkers substantially improved the ability to discriminate NSCLC. GNGT1 and NMU identified in the current study may empower further discovery of the molecular mechanisms underlying NSCLC's initiation and progression.

IL10 deficiency promotes alveolar enlargement and lymphoid dysmorphogenesis in the aged murine lung

The connection between aging-related immune dysfunction and the lung manifestations of aging is poorly understood. A detailed characterization of the aging IL10-deficient murine lung, a model of accelerated aging and frailty, reconciles features of both immunosenescence and lung aging in a coherent model. Airspace enlargement developed in the middle-aged (12 months old) and aged (20-22 months old) IL10-deficient lung punctuated by an expansion of macrophages and alveolar cell apoptosis. Compared to wild-type (WT) controls, the IL10-deficient lungs from young (4-month-old) mice showed increased oxidative stress which was enhanced in both genotypes by aging. Active caspase 3 staining was increased in the alveolar epithelial cells of aged WT and mutant lungs but was greater in the IL10-deficient milieu. Lung macrophages were increased in the aged IL10-deficient lungs with exuberant expression of MMP12. IL10 treatment of naïve and M2-polarized bone marrow-derived WT macrophages reduced MMP12 expression. Conditioned media studies demonstrated the secretome of aged mutant macrophages harbors reduced AECII prosurvival factors, specifically keratinocyte growth factor (KGF) and hepatocyte growth factor (HGF), promotes cell death, and reduces survival of primary alveolar epithelial cells. Compared to WT controls, aged IL10-deficient mice have increased parenchymal lymphoid collections comprised of a reduced number of apoptotic cells and B cells. We establish that IL10 is a key modulator of airspace homeostasis and lymphoid morphogenesis in the aging lung enabling macrophage-mediated alveolar epithelial cell survival and B-cell survival within tertiary lymphoid structures.