IL-10 Knockout Mice Research Articles

Optimizing therapeutic outcomes of immune checkpoint blockade by a microbial tryptophan metabolite

BackgroundDespite the great success, the therapeutic benefits of immune checkpoint inhibitors (ICIs) in cancer immunotherapy are limited by either various resistance mechanisms or ICI-associated toxic effects including gastrointestinal toxicity. Thus,...

THαβ Immunological Pathway as Protective Immune Response against Prion Diseases: An Insight for Prion Infection Therapy.

Prion diseases, including Creutzfeldt–Jakob disease, are mediated by transmissible proteinaceous pathogens. Pathological changes indicative of neuro-degeneration have been observed in the brains of affected patients. Simultaneously, microglial activation, along with the upregulation of pro-inflammatory cytokines, including IL-1 or TNF-α, have also been observed in brain tissue of these patients. Consequently, pro-inflammatory cytokines are thought to be involved in the pathogenesis of these diseases. Accelerated prion infections have been seen in interleukin-10 knockout mice, and type 1 interferons have been found to be protective against these diseases. Since interleukin-10 and type 1 interferons are key mediators of the antiviral THαβ immunological pathway, protective host immunity against prion diseases may be regulated via THαβ immunity. Currently no effective treatment strategies exist for prion disease; however, drugs that target the regulation of IL-10, IFN-alpha, or IFN-β, and consequently modulate the THαβ immunological pathway, may prove to be effective therapeutic options.

Jianpi Qingchang Decoction Ameliorates Chronic Colitis in Piroxicam-Induced IL-10 Knockout Mice by Inhibiting Endoplasmic Reticulum Stress.

Background Excessive endoplasmic reticulum (ER) stress in intestinal epithelial cells (IEC) may lead to impaired intestinal mucosal barrier function and then participate in the pathogenesis of ulcerative colitis (UC). Jianpi Qingchang decoction (JPQCD) has been shown to have protective effects on UC. However, further studies are needed to determine whether JPQCD regulates PERK/eIF2α/ATF4/CHOP pathways to play a role in treating UC. Methods IL-10 −/− mice were randomly assigned into five groups: control, model, low-dose JPQCD (JPQCD L), middle-dose JPQCD (JPQCD M), and high-dose JPQCD (JPQCD H). All groups except for the control group were given model feed containing 200 ppm piroxicam for 10 d to induce colitis. As a comparison, we used wild-type mice that were the progeny of IL-10+/− matings, bred in the same facility. The control group and wild-type mice were fed with common feed. At the same time, mice in each group were given corresponding drugs by gavage for 14 d. The disease activity index of mice in each group was evaluated daily. Colon tissues of mice were collected, colon length was measured, and pathological changes and ultrastructure of colon epithelial cells were observed. The effects of JPQCD on the PERK/eIF2α/ATF4/CHOP pathways were evaluated by western blotting and reverse transcription-polymerase chain reaction (RT-PCR). The expression of CHOP in colon tissue was detected by tissue immunofluorescence assay. The expression of NF-κB, p-NF-κB p65 protein was analyzed by western blotting; the level of IL-17 in colon tissue was detected by enzyme-linked immunosorbent assay (ELISA) and verified by examining NF-κB and IL-17 mRNA levels by RT-PCR. Results Compared with the control group, the model group showed significant colitis symptoms and severe colonic tissue damage. The results showed that JPQCD significantly reduced body weight loss, ameliorated disease activity index, and restored colon length in IL-10−/− mice with piroxicam-induced colitis. Western blotting and RT-PCR showed that the PERK/eIF2α/ATF4/CHOP pathway was activated in colon tissue of model mice, suggesting that the pathway is involved in the pathogenesis of ulcerative colitis (UC) and could become a potential therapeutic target. The JPQCD treatment inhibited the activation of the PERK/eIF2α/ATF4/CHOP pathway, alleviated the ER stress, and played a role in preventing and treating UC. In addition, JPQCD can also downregulate the protein of NF-κB, p-NF-κB p65, downregulate the mRNA expression of NF-κB, and reduce the content of IL-17 and its mRNA expression in colon tissues. Conclusion JPQCD may play a protective role in UC by regulating the PERK/eIF2α/ATF4/CHOP signaling pathway and relieving endoplasmic reticulum stress.

Interleukin-6 triggers toxic neuronal iron sequestration in response to pathological α-synuclein.

SUMMARYα-synuclein (α-syn) aggregation and accumulation drive neurodegeneration in Parkinson’s disease (PD). The substantia nigra of patients with PD contains excess iron, yet the underlying mechanism accounting for this iron accumulation is unclear. Here, we show that misfolded α-syn activates microglia, which release interleukin 6 (IL-6). IL-6, via its trans-signaling pathway, induces changes in the neuronal iron transcriptome that promote ferrous iron uptake and decrease cellular iron export via a pathway we term the cellular iron sequestration response, or CISR. The brains of patients with PD exhibit molecular signatures of the IL-6-mediated CISR. Genetic deletion of IL-6, or treatment with the iron chelator deferiprone, reduces pathological α-syn toxicity in a mouse model of sporadic PD. These data suggest that IL-6-induced CISR leads to toxic neuronal iron accumulation, contributing to synuclein-induced neurodegeneration.

P036 Identification and functional analysis of stromal subsets in experimental IBD mouse models

Abstract Background Single cell RNA sequencing data from the inflamed colon of inflammatory bowel disease (IBD) patients revealed the presence of different stromal cell/fibroblast subsets and showed their importance in IBD pathology. Up to now, it is unknown if and how the stroma cells affect disease progression. In this study we compared the stromal cell subsets in three IBD mouse models and explored the interaction between these stromal subsets and epithelial cells. Methods Stromal cell subset markers, including CD55, C-X-C motif chemokine 12 (CXCL12), podoplanin (PDPN), CD90 and CD73, were analyzed in the inflamed murine colon by flow cytometry in interleukin (IL)-10 knockout (KO) mice, dextran sulfate sodium(DSS)-induced colitis and the T cell transfer model. In order to explore the changes in stromal subsets upon colitis induction in vitro, short hairpin RNAs were used to silence target gene expression of these cellular markers in murine fibroblasts. Fibroblast proliferation and migration was studied in addition to the effects on immune cell trafficking and tissue regeneration. Results In all three colitis models, an increase in the total amount of stromal cells was observed. The percentages of PDPN+ and CD73+ stromal cells significantly increased during colitis in the IL-10 KO mice, while the percentage of CD55+, CD90+ and CXCL12+ stromal cells decreased. For the T cell transfer model, the abundance of CD73+, CD90+ and CD55+ stromal cells was enriched, while the percentage of CXCL12+ stromal cells was reduced. Interestingly, in contrast to the two other, in the DSS-mice the percentage of CXCL12+ stromal cells was significantly increased. In vitro experiments showed the importance of CD55 and CXCL12 for fibroblast proliferation and CD55 for their migration. Furthermore, the fibroblast supernatant obtained after the knockdown of CXCL12 decreased epithelial cell wound healing. On the contrary, knock-down of CD90 in the fibroblasts improved epithelial migration. Current experiments explore the immune regulatory properties of the fibroblast subsets. Conclusion The composition of stromal cell subsets is significantly changed in experimental colitis and differs between three established colitis mouse models. Therefore they may possibly reflect different human IBD subtypes observed in the clinic. Finally the defined subsets influence fibroblast behavior and epithelial regeneration.

Pomegranate Extract Improves Colitis in IL-10 Knockout Mice Fed a High Fat High Sucrose Diet.

The study tests the hypothesis that dietary pomegranate extract (PomX) supplementation attenuates colitis in a Western diet feed IL-10 deficient (IL-10-/-) murine model. Four-week-old male IL-10-/- mice are randomly assigned to a high fat high sucrose (HFHS) diet or a HFHS diet supplement with 0.25% PomX for 8 weeks. PomX supplementation lead to significantly lower histological score for colitis (2.6 ± 0.5 vs 3.9 ± 1.0), lower spleen weight (0.11 ± 0.01 vs 0.15 ± 0.02),and lower circulating Interleukin 6(IL-6) levels (15.8±2.2vs29.5±5.5)compared with HFHS fed controls. RNAseq analysis of colonic tissues showed 483 downregulated and 263 upregulated genes with PomX supplementation, which are mainly associated with inflammatory responses, defenses, and neutrophil degranulation. In addition, PomX treatment affects the cecal microbiome with increased alpha diversity, altered microbial composition, and increased levels of the tryptophan-related microbial metabolite indole propionate. The data demonstrate that dietary PomX supplementation ameliorated colitis and lowered inflammatory markers in HFHS fed IL-10-/- mice. These data support the anti-inflammatory effects of dietary PomX supplementation for IBD and a potential mediating role of gut microbiome, suggesting the need for future clinical studies to explore the use of PomX dietary supplementation in IBD patients.

Antioxidant and anti-inflammatory activity of curcumin transdermal gel in an IL-10 knockout mouse model of inflammatory bowel disease.

Inflammatory bowel diseases are a group of inflammatory disorders of the gastrointestinal tract. Their prevalence is still low in Brazil, but the incidence is increasing annually. A variety of compounds present in Curcuma longa L., particularly curcumin, have been shown to reduce oxidative stress and aid in the prevention of associated diseases. This study aimed to assess the effect of curcumin transdermal gel on oxidative stress and intestinal inflammation in IL-10 knockout mice. Female mice were divided into four groups: a control group (C0) treated with vehicle and three experimental groups treated with transdermal gel containing 50 (C50), 75 (C75), and 100 (C100) mg curcumin kg-1 body weight. Colon malondialdehyde concentrations were lower in C50 and C75 groups. C100 treatment led to reduced catalase activity in the small intestine, whereas C50, C75, and C100 treatments resulted in decreased catalase activity in the colon. In contrast, superoxide dismutase activity increased in the small intestine of C50 and C75 mice and decreased in the colon of C50, C75, and C100 mice. Glutathione S-transferase activity increased in the small intestine and decreased in the colon of C75 animals. These findings suggest that curcumin transdermal gel exerts a protective effect against oxidative stress.

Gastric tumorigenesis induced by combining Helicobacter pylori infection and chronic alcohol through IL-10 inhibition

Helicobacter pylori infection and alcohol intake are independent risk factors in gastric carcinogenesis; however, until now, the combined effect of H. pylori infection and alcohol consumption and the specific mechanism is still problematic. Here, we developed a series of mouse models that progress from chronic gastritis to gastric cancer, induced by infecting H. pylori combined with chronic alcohol consumption and then determining the molecular mechanism of the progression by flow cytometry, western blotting, qPCR, Mito Traker assay in the gastric cancer and T-cell lines. Interleukin-10 (IL-10) knockout mice was used to determine whether IL-10 deficiency directly contributes to H. pylori and alcohol induced gastric tumorigenesis. Alcohol consumption, together with H. pylori infection, causes gastric cancer; IL-10 downregulation and mitochondrial metabolic dysfunction in CD8+ cells are also involved. IL-10 knockout accelerates tumor development in mice with either H. pylori infection or alcohol induced gastric cancer or both. IL-10 inhibits glucose uptake and glycolysis and promotes oxidative phosphorylation with lactate inhibition. Consequently, in the absence of IL-10 signaling, CD8+ cells accumulate damaged mitochondria in a mouse model of gastric cancer induced with the combination of alcohol plus H. pylori infection, and this results in mitochondrial dysfunction and production of IL-1β. IL-1β promotes H. pylori infection and reduces NKX6.3 gene expression, resulting in increased cancer cell survival and proliferation. Gastric cancer can be induced by the combination of H. pylori infection and chronic alcohol consumption through IL-10 inhibition induced CD8+ cells dysfunction and NKX6.3 suppression.

Exercise Training Protects Against Heart Failure Via Expansion of Myeloid-Derived Suppressor Cells Through Regulating IL-10/STAT3/S100A9 Pathway.

Exercise training (ET) has a protective effect on the progression of heart failure, however, the specific mechanism has not been fully explored. Myeloid-derived suppressor cells (MDSCs) are a group of myeloid-derived immunosuppressive cells, which showed a protective effect in the progression of heart failure. Thus, we hypothesized that the protective effect of ET on heart failure may be related to the infiltration of MDSCs. C57BL/6 mice were made to run on a treadmill 6× a week for 4 weeks followed by isoproterenol injection from third week. Heart function was evaluated by echocardiography and the proportion of MDSCs was detected by flow cytometry. Hypertrophic markers, cardiac fibrosis, and inflammatory factors were detected by real-time PCR, ELISA, histological staining, and Western blot. ET treatment in isoproterenol-induced heart failure mice (n=7) enhanced cardiac function (57% increase in FS%, P=0.002) and improved morphological changes compared with isoproterenol mice (n=17). ET further caused 79% increasing in cardiac MDSCs in isoproterenol mice (P<0.001). In addition, depletion of MDSCs by 5-Fluorouracil blunted the cardio-protective effect of ET. T-cell proliferation assay showed that ET did not affect the suppressive activity of MDSCs. Furthermore, we found that ET activated the secretion of IL (interleukin)-10 by macrophages in isoproterenol mice. MDSCs expansion and cardio protection was not present in tamoxifen-inducible macrophage-specific IL-10 knockout mice. Western blot results confirmed that IL-10 regulated the differentiation of MDSCs through the translocation of p-STAT3 (signal transducer and activator of transcription 3)/S100A9 (S100 calcium-binding protein A9) to the nucleus. ET could increase MDSCs by stimulating the secretion of IL-10 from macrophage, which was through IL-10/STAT3/S100A9 signaling pathway, thereby achieving the role of heart protection.

Intermittent antibiotic treatment accelerated the development of colitis in IL-10 knockout mice

Background and aimsMany epidemiological studies suggest an association between antibiotic exposure and the development of inflammatory bowel disease [IBD]. However, the majority of these studies are observational and still the question remains, “Does the specific antibiotic administration regimen play a role in the development of colitis?” This study aimed to compare the possible effects of continuous and intermittent antibiotic exposure on the development of colitis using a colitis-susceptible IL-10 knockout [IL-10–/–] mouse model. MethodsIL-10–/– mice [C57BL/6] were randomly assigned to a non-antibiotic group, continuous antibiotic group and intermittent antibiotic group, and observed for 30 weeks. The antibiotic cocktail was given via the drinking water. The differential response to antibiotics was assessed. ResultsIntermittent antibiotic treatment resulted in severe colitis with early disease onset in IL-10–/– mice. Higher unit colon weight and spleen weight were observed in intermittent antibiotic-treated mice but not in the continuous antibiotic group. Moreover, intermittent antibiotic treatment aggravated epithelial damage and colonic inflammation, mucosal barrier dysfunction and colonic allergic sensitization in IL-10–/– mice, whereas continuous antibiotic treatment ameliorated these symptoms. Male IL-10–/– mice with intermittent antibiotic exposure were more susceptible to colonic inflammation and allergic response than females. ConclusionsIn summary, intermittent antibiotic exposure accelerated the development of severe colitis more than continuous antibiotic exposure in IL-10–/– male mice. In addition to the colonic damage and impaired barrier function, stimulation of allergic response may play a role in accelerating the development of colitis in genetically susceptible mice.

IL-4 expressing cells are recruited to nerve after injury and promote regeneration

Interleukin-4 (IL-4) has garnered interest as a cytokine that mediates regeneration across multiple tissues including peripheral nerve. Within nerve, we previously showed endogenous IL-4 was critical to regeneration across nerve gaps. Here, we determined a generalizable role of IL-4 in nerve injury and regeneration. In wild-type (WT) mice receiving a sciatic nerve crush, IL-4 expressing cells preferentially accumulated within the injured nerve compared to affected sites proximal, such as dorsal root ganglia (DRGs), or distal muscle. Immunohistochemistry and flow cytometry confirmed that eosinophils (CD45+, CD11b+, CD64−, Siglec-F+) were sources of IL-4 expression. Examination of targets for IL-4 within nerve revealed macrophages, as well as subsets of neurons expressed IL-4R, while Schwann cells expressed limited IL-4R. Dorsal root ganglia cultures were exposed to IL-4 and demonstrated an increased proportion of neurons that extended axons compared to cultures without IL-4 (control), as well as longer myelinated axons compared to cultures without IL-4. The role of endogenous IL-4 during nerve injury and regeneration in vivo was assessed following a sciatic nerve crush using IL-4 knockout (KO) mice. Loss of IL-4 affected macrophage accumulation within injured nerve compared to WT mice, as well as shifted macrophage phenotype towards a CD206- phenotype with altered gene expression. Furthermore, this loss of IL-4 delayed initial axon regeneration from the injury crush site and subsequently delayed functional recovery and re-innervation of neuromuscular junctions compared to wild-type mice. Given the role of endogenous IL-4 in nerve regeneration, exogenous IL-4 was administered daily to WT mice following a nerve crush to examine regeneration. Daily IL-4 administration increased early axonal extension and CD206+ macrophage accumulation but did not alter functional recovery compared to untreated mice. Our data demonstrate IL-4 promotes nerve regeneration and recovery after injury.

Annexin A1 Mimetic Peptide Ac2-26 Modulates the Function of Murine Colonic and Human Mast Cells.

Mast cells (MCs) are main effector cells in allergic inflammation and after activation, they release stored (histamine, heparin, proteases) and newly synthesized (lipid mediators and cytokines) substances. In the gastrointestinal tract the largest MC population is located in the lamina propria and submucosa whereas several signals such as the cytokine IL-4, seem to increase the granule content and to stimulate a remarkable expansion of intestinal MCs. The broad range of MC-derived bioactive molecules may explain their involvement in many different allergic disorders of the gastrointestinal tract. Annexin A1 (AnxA1) is a 37 KDa glucocorticoid induced monomeric protein selectively distributed in certain tissues. Its activity can be reproduced by mimetic peptides of the N-terminal portion, such as Ac2-26, that share the same receptor FPR-L1. Although previous reports demonstrated that AnxA1 inhibits MC degranulation in murine models, the effects of exogenous peptide Ac2-26 on intestinal MCs or the biological functions of the Ac2-26/FPR2 system in human MCs have been poorly studied. To determine the effects of Ac2-26 on the function of MCs toward the possibility of AnxA1-based therapeutics, we treated WT and IL-4 knockout mice with peptide Ac2-26, and we examined the spontaneous and compound 48/80 stimulated colonic MC degranulation and cytokine production. Moreover, in vitro, using human mast cell line HMC-1 we demonstrated that exogenous AnxA1 peptide is capable of interfering with the HMC-1 degranulation in a direct pathway through formyl peptide receptors (FPRs). We envisage that our results can provide therapeutic strategies to reduce the release of MC mediators in inflammatory allergic processes.

Interleukin-6 actions in the hypothalamus protects against obesity and is involved in the regulation of neurogenesis

BackgroundInterleukin-6 (IL6) produced in the context of exercise acts in the hypothalamus reducing obesity-associated inflammation and restoring the control of food intake and energy expenditure. In the hippocampus, some of the beneficial actions of IL6 are attributed to its neurogenesis-inducing properties. However, in the hypothalamus, the putative neurogenic actions of IL6 have never been explored, and its potential to balance energy intake can be an approach to prevent or attenuate obesity.MethodsWild-type (WT) and IL6 knockout (KO) mice were employed to study the capacity of IL6 to induce neurogenesis. We used cell labeling with Bromodeoxyuridine (BrdU), immunofluorescence, and real-time PCR to determine the expression of markers of neurogenesis and neurotransmitters. We prepared hypothalamic neuroprogenitor cells from KO that were treated with IL6 in order to provide an ex vivo model to further characterizing the neurogenic actions of IL6 through differentiation assays. In addition, we analyzed single-cell RNA sequencing data and determined the expression of IL6 and IL6 receptor in specific cell types of the murine hypothalamus.ResultsIL6 expression in the hypothalamus is low and restricted to microglia and tanycytes, whereas IL6 receptor is expressed in microglia, ependymocytes, endothelial cells, and astrocytes. Exogenous IL6 reduces diet-induced obesity. In outbred mice, obesity-resistance is accompanied by increased expression of IL6 in the hypothalamus. IL6 induces neurogenesis-related gene expression in the hypothalamus and in neuroprogenitor cells, both from WT as well as from KO mice.ConclusionIL6 induces neurogenesis-related gene expression in the hypothalamus of WT mice. In KO mice, the neurogenic actions of IL6 are preserved; however, the appearance of new fully differentiated proopiomelanocortin (POMC) and neuropeptide Y (NPY) neurons is either delayed or disturbed.

EGFR-IL-6 Signaling Axis Mediated the Inhibitory Effect of Methylseleninic Acid on Esophageal Squamous Cell Carcinoma.

Epidemiological and experimental evidence indicate that selenium is associated with a reduced risk of some cancers, including esophageal cancer. However, the exact mechanism is still unclear. In the present study, we used esophageal squamous cell carcinoma (ESCC) cell lines and animal models to explore the anti-cancer mechanism of methylseleninic acid (MSA). Firstly, MSA treatment dramatically attenuated Epidermal Growth Factor Receptor (EGFR) protein expression but did not alter mRNA levels in ESCC cells. On the contrary, EGFR overexpression partly abolished the inhibitory effect of MSA. With a microRNA-array, we found MSA up-regulated miR-146a which directly targeted EGFR, whereas miR-146a inhibitor antagonized MSA-induced decrease of EGFR protein. We further used 4-nitroquinoline-1-oxide (4NQO)-induced esophageal tumor mice model to evaluate the inhibitory effect of MSA in vivo. MSA treatment significantly decreased the tumor burden and EGFR protein expression in tumor specimens. Furthermore, MSA treatment inhibited EGFR pathway and subsequntly reduced Interleukin-6 (IL-6) secretion in the supernatant of cancer cell lines. MSA-induced IL-6 suppression was EGFR-dependent. To further evaluate the association of IL-6 and the anti-tumor effect of MSA on esophageal cancer, we established the 4NQO-induced esophageal tumor model in IL-6 knock-out (IL-6 KO) mice. The results showed that IL-6 deficiency did not affect esophageal tumorigenesis in mice, but the inhibitory effect of MSA was abolished in IL-6 KO mice. In conclusion, our study demonstrated that MSA upregulated miR-146a which directly targeted EGFR, and inhibited EGFR protein expression and pathway activity, subsequently decreased IL-6 secretion. The inhibitory effect of MSA on esophageal cancer was IL-6 dependent. These results suggested that MSA may serve as a potential drug treating esophageal cancer.

Kupffer cell restoration after partial hepatectomy is mainly driven by local cell proliferation in IL-6-dependent autocrine and paracrine manners.

Kupffer cells (KCs), which are liver-resident macrophages, originate from the fetal yolk sac and represent one of the largest macrophage populations in the body. However, the current data on the origin of the cells that restore macrophages during liver injury and regeneration remain controversial. Here, we address the question of whether liver macrophage restoration results from circulating monocyte infiltration or local KC proliferation in regenerating livers after partial hepatectomy (PHx) and uncover the underlying mechanisms. By using several strains of genetically modified mice and performing immunohistochemical analyses, we demonstrated that local KC proliferation mainly contributed to the restoration of liver macrophages after PHx. Peak KC proliferation was impaired in Il6-knockout (KO) mice and restored after the administration of IL-6 protein, whereas KC proliferation was not affected in Il4-KO or Csf2-KO mice. The source of IL-6 was identified using hepatocyte- and myeloid-specific Il6-KO mice and the results revealed that both hepatocytes and myeloid cells contribute to IL-6 production after PHx. Moreover, peak KC proliferation was also impaired in myeloid-specific Il6 receptor-KO mice after PHx, suggesting that IL-6 signaling directly promotes KC proliferation. Studies using several inhibitors to block the IL-6 signaling pathway revealed that sirtuin 1 (SIRT1) contributed to IL-6-mediated KC proliferation in vitro. Genetic deletion of the Sirt1 gene in myeloid cells, including KCs, impaired KC proliferation after PHx. In conclusion, our data suggest that KC repopulation after PHx is mainly driven by local KC proliferation, which is dependent on IL-6 and SIRT1 activation in KCs.

Regulatory T Cells Exhibit Interleukin-33-Dependent Migratory Behavior during Skin Barrier Disruption.

Regulatory T cells (Tregs) suppress immune responses and maintain immunological self-tolerance and homeostasis. We currently investigated relationships between skin barrier condition and Treg behavior using skin barrier-disrupted mice. Skin barrier disruption was induced by repeated topical application of 4% sodium dodecyl sulfate (SDS) on mice. The number of CD4+ forkhead box protein P3 (Foxp3)+ Tregs was higher in 4% SDS-treated skins than in controls. This increasing was correlated with the degree of acanthosis. The numbers of interleukin (IL)-10+ and transforming growth factor (TGF)-β+ Tregs also increased in 4% SDS-treated skins. Localization of IL-33 in keratinocytes shifted from nucleus to cytoplasm after skin barrier disruption. Notably, IL-33 promoted the migration of Tregs in chemotaxis assay. The skin infiltration of Tregs was cancelled in IL-33 neutralizing antibody-treated mice and IL-33 knockout mice. Thus, keratinocyte-derived IL-33 may induce Treg migration into barrier-disrupted skin to control the phase transition between healthy and inflammatory conditions.

Progranulin attenuated asthma inflammation by inhibiting the expression of IL-6

Objective: To investigate the role and mechanism of progranulin (PGRN) in asthma. Methods: Control group and model group were set up in wild and IL-6 knockout (IL-6 ko) mice, respectively. For asthma model, mice were intraperitoneally sensitized with 100 μg OVA on days 0 and 7, followed by aerosol challenges with 5% OVA for 30 min per day from day 14 to 21, and mice were sacrificed 24 h after the last challenge. The mice in control group were treated in the same way with PBS. Bronchoalveolar lavage fluid (BALF) was collected for leukocytes count and differential count. The pathological changes of lung tissues were observed by H&E staining. The cytokines in lung homogenate, serum and BALF were detected by Q-PCR and ELISA. The in vitro model of asthma was induced by stimulating A549 or BEAS-2B cells with IL-13. Each group was replicated in three wells and four groups were designed: PBS group, IL-13 treatment group, IL-13 + rhPGRN treatment group, inhibitors of p38 phosphorylation (SB203508) treatment group. The cells or supernatant were collected after 0~48 h. PGRN and IL-6 levels were determined by Q-PCR and ELISA, the level of p38 phosphorylation was tested by Western blot (WB). Results: Compared with control group, PGRN levels were decreased in lung homogenate and BALF (P＜0.05), and PGRN presented a downtrend in serum, however, the level of IL-6 in BALF was increased in asthma mice (P＜0.01). In IL-6 ko asthma mice, compared with the wild asthma mice, leukocytes, especially neutrophils in BALF were decreased (P＜0.05), but PGRN was increased (P＜0.05), lung pathological damage was significantly alleviated. In vitro experiments, compared with PBS group, PGRN level was decreased (P＜0.05), IL-6 level was increased (P＜0.01), phosphorylation of p38 was activated in IL-13 treatment group. Compared with IL-13 treatment group, in IL-13 + PGRN treatment group, IL-6 level was decreased (P＜0.05); phosphorylation of p38 was inhibited (P＜0.05); and the production of IL-6 (P＜0.05) was decreased after treatment with inhibitor of p38 phosphorylation. Conclusion: PGRN inhibited the production of IL-6 by suppressing the p38 phosphorylation to alleviate asthmatic airway inflammation.

Effects of Eggshell Membrane on Keratinocyte Differentiation and Skin Aging In Vitro and In Vivo.

Skin aging is one of the hallmarks of the aging process that causes physiological and morphological changes. Recently, several nutritional studies were conducted to delay or suppress the aging process. This study investigated whether nutritional supplementation of the eggshell membrane (ESM) has a beneficial effect on maintaining skin health and improving the skin aging process in vitro using neonatal normal human epidermal keratinocytes (NHEK-Neo) and in vivo using interleukin-10 knockout (IL-10 KO) mice. In NHEK-Neo cells, 1 mg/mL of enzymatically hydrolyzed ESM (eESM) upregulated the expression of keratinocyte differentiation markers, including keratin 1, filaggrin and involucrin, and changed the keratinocyte morphology. In IL-10 KO mice, oral supplementation of 8% powdered-ESM (pESM) upregulated the expression of growth factors, including transforming growth factor β1, platelet-derived growth factor-β and connective tissue growth factor, and suppressed skin thinning. Furthermore, voltage-gated calcium channel, transient receptor potential cation channel subfamily V members were upregulated by eESM treatment in NHEK-Neo cells and pESM supplementation in IL-10 KO mice. Collectively, these data suggest that ESM has an important role in improving skin health and aging, possibly via upregulating calcium signaling.

Monoclonal Antibody Requires Immunomodulation for Efficacy Against Acinetobacter baumannii Infection.

Monoclonal antibodies (mAbs) are gaining significant momentum as novel therapeutics for infections caused by antibiotic-resistant bacteria. We evaluated the mechanism by which antibacterial mAb therapy protects against Acinetobacter baumannii infections. Anticapsular mAb enhanced macrophage opsonophagocytosis and rescued mice from lethal infections by harnessing complement, macrophages, and neutrophils; however, the degree of bacterial burden did not correlate with survival. Furthermore, mAb therapy reduced proinflammatory (interleukin-1β [IL-1β], IL-6, tumor necrosis factor-α [TNF-α]) and anti-inflammatory (IL-10) cytokines, which correlated inversely with survival. Although disrupting IL-10 abrogated the survival advantage conferred by the mAb, IL-10-knockout mice treated with mAb could still survive if TNF-α production was suppressed directly (via anti-TNF-α neutralizing antibody) or indirectly (via macrophage depletion). Thus, even for a mAb that enhances microbial clearance via opsonophagocytosis, clinical efficacy required modulation of pro- and anti-inflammatory cytokines. These findings may inform future mAb development targeting bacteria that trigger the sepsis cascade.

Temporal overexpression of IL-22 and Reg3γ differentially impacts the severity of experimental autoimmune encephalomyelitis.

IL-22 is an alpha-helical cytokine which belongs to the IL-10 family of cytokines. IL-22 is produced by RORγt+ innate and adaptive lymphocytes, including ILC3, γδ T, iNKT, Th17 and Th22 cells and some granulocytes. IL-22 receptor is expressed primarily by non-haematopoietic cells. IL-22 is critical for barrier immunity at the mucosal surfaces in the steady state and during infection. Although IL-22 knockout mice were previously shown to develop experimental autoimmune encephalomyelitis (EAE), a murine model of multiple sclerosis (MS), how temporal IL-22 manipulation in adult mice would affect EAE course has not been studied previously. In this study, we overexpressed IL-22 via hydrodynamic gene delivery or blocked it via neutralizing antibodies in C57BL/6 mice to explore the therapeutic impact of IL-22 modulation on the EAE course. IL-22 overexpression significantly decreased EAE scores and demyelination, and reduced infiltration of IFN-γ+IL-17A+Th17 cells into the central nervous system (CNS). The neutralization of IL-22 did not alter the EAE pathology significantly. We show that IL-22-mediated protection is independent of Reg3γ, an epithelial cell-derived antimicrobial peptide induced by IL-22. Thus, overexpression of Reg3γ significantly exacerbated EAE scores, demyelination and infiltration of IFN-γ+IL-17A+ and IL-17A+GM-CSF+Th17 cells to CNS. We also show that Reg3γ may inhibit IL-2-mediated STAT5 signalling and impair expansion of Treg cells in vivo and in vitro. Finally, Reg3γ overexpression dramatically impacted intestinal microbiota during EAE. Our results provide novel insight into the role of IL-22 and IL-22-induced antimicrobial peptide Reg3γ in the pathogenesis of CNS inflammation in a murine model of MS.