IL-10 Knockout Mice Research Articles

Knockout of IL-6 mitigates cold water-immersion restraint stress-induced intestinal epithelial injury and apoptosis.

Interleukin-6 (IL-6) is essential for maintaining intestinal epithelial homeostasis. Although cold water-immersion restraint (CWIR) stress is commonly used to induce in vivo gastric injury, it also affects intestinal epithelial permeability. Although IL-6 is increased in response to acute physiological and psychological stress, its exact effects on the pathophysiology of the intestinal epithelium in response to acute CWIR stress remain unknown. We used IL-6 knockout (KO) mice with acute CWIR modeling to investigate the effect of IL-6 deficiency on intestinal epithelial morphology and pathological damage using histological staining assays under the acute stress. We detected jejunal epithelial apoptosis using TUNEL and standard molecular experiments. CWIR caused intestinal epithelial damage, which was alleviated by the absence of IL-6, as evidenced by morphological changes and goblet cell and intestinal permeability alteration. IL-6 KO also reduced CWIR-mediated inflammatory levels and improved stress defense. Meanwhile, IL-6 deficiency decreased the intestinal epithelial apoptosis induced by CWIR administration. This IL-6 KO-led effect depended more on mitochondrial AIF signaling rather than the traditional caspase pathway. As a result, we concluded that acute CWIR-induced severe intestinal damage and jejunal epithelium apoptosis could be alleviated by IL-6 deficiency, implying a protective effect of IL-6 deficiency on the intestines under acute stress. The findings shed new light on treating CWIR-induced intestinal disorders by inhibiting IL-6 signaling.

IL-18 deficiency ameliorates the progression from AKI to CKD

Inflammation is an important factor in the progression from acute kidney injury (AKI) to chronic kidney disease (CKD). The role of interleukin (IL)-18 in this progression has not been examined. We aimed to clarify whether and how IL-18 limits this progression. In a folic acid induced renal injury mouse model, we studied the time course of kidney injury and renal IL-18 expression. In wild-type mice following injection, renal IL-18 expression increased. In parallel, we characterized other processes, including at day 2, renal tubular necroptosis assessed by receptor-interacting serine/threonine-protein kinase1 (RIPK1) and RIPK3; at day 14, transdifferentiation (assessed by transforming growth factor β1, vimentin and E-cadherin); and at day 30, fibrosis (assessed by collagen 1). In IL-18 knockout mice given folate, compared to wild-type mice, tubular damage and necroptosis, transdifferentiation, and renal fibrosis were attenuated. Importantly, IL-18 deletion decreased numbers of renal M1 macrophages and M1 macrophage cytokine levels at day 14, and reduced M2 macrophages numbers and macrophage cytokine expression at day 30. In HK-2 cells, IL-18 knockdown attenuated necroptosis, transdifferentiating and fibrosis.In patients with tubulointerstitial nephritis, IL-18 protein expression was increased on renal biopsies using immunohistochemistry. We conclude that genetic IL-18 deficiency ameliorates renal tubular damage, necroptosis, cell transdifferentiation, and fibrosis. The renoprotective role of IL-18 deletion in the progression from AKI to fibrosis may be mediated by reducing a switch in predominance from M1 to profibrotic M2 macrophages during the process of kidney repair.

Interleukin-6 and indoleamine-2,3-dioxygenase as potential adjuvant targets for Papillomavirus-related tumors immunotherapy.

High-risk Human papillomavirus (HPV) infections represent an important public health issue. Nearly all cervical malignancies are associated with HPV, and a range of other female and male cancers, such as anogenital and oropharyngeal. Aiming to treat HPV-related tumors, our group developed vaccines based on the genetic fusion of the HSV-1 glycoprotein D (gD) with the HPV-16 E7 oncoprotein (gDE7 vaccines). Despite the promising antitumor results reached by gDE7 vaccines in mice, combined therapies may increase the therapeutic effects by improving antitumor responses and halting immune suppressive mechanisms elicited by tumor cells. Considering cancer immunosuppressive mechanisms, indoleamine-2,3-dioxygenase (IDO) enzyme and interleukin-6 (IL-6) stand out in HPV-related tumors. Since IL-6 sustained the constitutive IDO expression, here we evaluated the therapeutic outcomes achieved by the combination of active immunotherapy based on a gDE7 protein-based vaccine with adjuvant treatments involving blocking IDO, either by use of IDO inhibitors or IL-6 knockout mice. C57BL/6 wild-type (WT) and transgenic IL-6-/- mice were engrafted with HPV16-E6/E7-expressing TC-1 cells and treated with 1-methyl-tryptophan isoforms (D-1MT and DL-1MT), capable to inhibit IDO. In vitro, the 1MT isoforms reduced IL-6 gene expression and IL-6 secretion in TC-1 cells. In vivo, the multi-targeted treatment improved the antitumor efficacy of the gDE7-based protein vaccine. Although the gDE7 immunization achieves partial tumor mass control in combination with D-1MT or DL-1MT in WT mice or when administered in IL-6-/- mice, the combination of gDE7 and 1MT in IL-6-/- mice further enhanced the antitumor effects, reaching total tumor rejection. The outcome of the combined therapy was associated with an increased frequency of activated dendritic cells and decreased frequencies of intratumoral polymorphonuclear myeloid-derived suppressor cells and T regulatory cells. In conclusion, the present study demonstrated that IL-6 and IDO negatively contribute to the activation of immune cells, particularly dendritic cells, reducing gDE7 vaccine-induced protective immune responses and, therefore, opening perspectives for the use of combined strategies based on inhibition of IL-6 and IDO as immunometabolic adjuvants for immunotherapies against HPV-related tumors.

Exogenous Oncostatin M induces Cardiac Dysfunction, Musculoskeletal Atrophy, and Fibrosis.

Musculoskeletal diseases such as muscular dystrophy, cachexia, osteoarthritis, and rheumatoid arthritis impair overall physical health and reduce survival. Patients suffer from pain, dysfunction, and dysmobility due to inflammation and fibrosis in bones, muscles, and joints, both locally and systemically. The Interleukin-6 (IL-6) family of cytokines, most notably IL-6, is implicated in musculoskeletal disorders and cachexia. Here we show elevated circulating levels of OSM in murine pancreatic cancer cachexia and evaluate the effects of the IL-6 family member, Oncostatin M (OSM), on muscle and bone using adeno-associated virus (AAV) mediated over-expression of murine OSM in wildtype and IL-6 deficient mice. Initial studies with high titer AAV-OSM injection yielded high circulating OSM and IL-6, thrombocytosis, inflammation, and 60% mortality without muscle loss within 4days. Subsequently, to mimic OSM levels in cachexia, a lower titer of AAV-OSM was used in wildtype and Il6 null mice, observing effects out to 4weeks and 12weeks. AAV-OSM caused muscle atrophy and fibrosis in the gastrocnemius, tibialis anterior, and quadriceps of the injected limb, but these effects were not observed on the non-injected side. In contrast, OSM induced both local and distant trabecular bone loss as shown by reduced bone volume, trabecular number, and thickness, and increased trabecular separation. OSM caused cardiac dysfunction including reduced ejection fraction and reduced fractional shortening. RNA-sequencing of cardiac muscle revealed upregulation of genes related to inflammation and fibrosis. None of these effects were different in IL-6 knockout mice. Thus, OSM induces local muscle atrophy, systemic bone loss, tissue fibrosis, and cardiac dysfunction independently of IL-6, suggesting a role for OSM in musculoskeletal conditions with these characteristics, including cancer cachexia.

CircSMAD4 Promotes Experimental Colitis and Impairs Intestinal Barrier Functions by Targeting Janus Kinase 2 Through Sponging miR-135a-5p.

Numerous studies have explored the association between circular RNAs [circRNAs] and Crohn's disease [CD]. However, the pathological role, biological functions, and molecular mechanisms of circRNAs in CD have not been fully elucidated. The circRNA microarray analysis was performed to identify deregulated circRNAs in colon tissues. The identified circRNAs were verified through quantitative real-time polymerase chain reaction [qRT-PCR]. In vivo and in vitro functional studies were performed to verify the role of circSMAD4 in CD and investigate the mechanisms involved. We found that circSMAD4 was the most significantly upregulated circRNA. The expression level of circSMAD4 was positively correlated with levels of inflammatory factors. Overexpression of circSMAD4 impaired tight junction [TJ] proteins and enhanced apoptosis of epithelial cells. These effects were reversed by treatment with miR-135a-5p mimic. Mechanistic studies showed that circSMAD4 exerts its effects on CD by 'sponging' miR-135a-5p to regulate Janus kinase 2 [JAK2]. Si-circSMAD4 delivery through microspheres ameliorated experimental colitis and protected the intestinal barrier function in IL-10 knockout mice. This study shows that circSMAD4 regulates the progression of experimental colitis via the miR-135a-5p/JAK2 signalling axis and it may be a potential therapeutic target.

IL-6 deletion decreased REV-ERBα protein and influenced autophagy and mitochondrial markers in the skeletal muscle after acute exercise

Interleukin 6 (IL-6) acts as a pro and anti-inflammatory cytokine, has an intense correlation with exercise intensity, and activates various pathways such as autophagy and mitochondrial unfolded protein response. Also, IL-6 is interconnected to circadian clock-related inflammation and can be suppressed by the nuclear receptor subfamily 1, group D, member 1 (Nr1d1, protein product REV-ERBα). Since IL-6 is linked to physical exercise-modulated metabolic pathways such as autophagy and mitochondrial metabolism, we investigated the relationship of IL-6 with REV-ERBα in the adaptations of these molecular pathways in response to acute intense physical exercise in skeletal muscle. The present study was divided into three experiments. In the first one, wild-type (WT) and IL-6 knockout (IL-6 KO) mice were divided into three groups: Basal time (Basal; sacrificed before the acute exercise), 1 hour (1hr post-Ex; sacrificed 1 hour after the acute exercise), and 3 hours (3hr post-Ex; sacrificed 3 hours after the acute exercise). In the second experiment, C2C12 cells received IL-6 physiological concentrations or REV-ERBα agonist, SR9009. In the last experiment, WT mice received SR9009 injections. After the protocols, the gastrocnemius muscle or the cells were collected for reverse transcription-quantitative polymerase chain reaction (RTq-PCR) and immunoblotting techniques. In summary, the downregulation of REV-ERBα, autophagic flux, and most mitochondrial genes was verified in the IL-6 KO mice independent of exercise. The WT and IL-6 KO treated with SR9009 showed an upregulation of autophagic genes. C2C12 cells receiving IL-6 did not modulate the Nr1d1 mRNA levels but upregulated the expression of some mitochondrial genes. However, when treated with SR9009, IL-6 and mitochondrial gene expression were upregulated in C2C12 cells. The autophagic flux in C2C12 suggest the participation of REV-ERBα protein in the IL-6-induced autophagy. In conclusion, the present study verified that the adaptations required through physical exercise (increases in mitochondrial content and improvement of autophagy machinery) might be intermediated by an interaction between IL-6 and REVERBα.

NIL10: A New IL10-Receptor Binding Nanoparticle That Induces Cardiac Protection in Mice and Pigs Subjected to Acute Myocardial Infarction through STAT3/NF-κB Activation.

(1) Background: Early response after acute myocardial infarction (AMI) prevents extensive cardiac necrosis, in which inflammation resolution, including expression of anti-inflammatory interleukin-10 (IL-10), may play a key role. (2) Methods: We synthesized NIL10, a micelle-based nanoparticle, to target IL-10 receptor in mice and pigs subjected to AMI. (3) Results: Administration of NIL10 induced cardiac protection of wild-type and IL-10 knockout mice and pigs subjected to AMI. Cardiac protection was not induced in IL-10-receptor null mice, as shown by a significant recovery of cardiac function, in which inflammatory foci and fibrosis were strongly reduced, together with the finding that resolving M2-like macrophage populations were increased after day 3 of reperfusion. In addition, anti-inflammatory cytokines, including IL-4, IL-7, IL-10, IL-13, IL-16, and IL-27 were also elevated. Mechanistically, NIL10 induced activation of the IL-10 receptor/STAT-3 signaling pathway, and STAT3-dependent inhibition of nuclear translocation of pro-inflammatory NF-ĸB transcription factor. (4) Conclusions: Taken together, we propose using NIL10 as a novel therapeutic tool against AMI-induced cardiac damage.

Investigation and modulation of interleukin-6 following subarachnoid hemorrhage: targeting inflammatory activation for cerebral vasospasm

BackgroundCerebral vasospasm (CV) can contribute to significant morbidity in subarachnoid hemorrhage (SAH) patients. A key unknown is how CV induction is triggered following SAH.MethodsHuman aneurysmal blood and cerebral spinal fluid were collected for evaluation. To confirm mechanism, c57/bl6 wild type and c57/bl6 IL-6 female knockout (KO) mice were utilized with groups: saline injected, SAH, SAH + IL-6 blockade, SAH IL-6 KO, SAH IL-6 KO + IL-6 administration, SAH + p-STAT3 inhibition. Dual-labeled microglia/myeloid mice were used to show myeloid diapedesis. For SAH, 50 μm blood was collected from tail puncture and administered into basal cisterns. IL-6 blockade was given at various time points. Various markers of neuroinflammation were measured with western blot and immunohistochemistry. Cerebral blood flow was also measured. Vasospasm was measured via cardiac injection of India ink/gelatin. Turning test and Garcia’s modified SAH score were utilized. P < 0.05 was considered significant.ResultsIL-6 expression peaked 3 days following SAH (p < 0.05). Human IL-6 was increased in aneurysmal blood (p < 0.05) and in cerebral spinal fluid (p < 0.01). Receptor upregulation was periventricular and perivascular. Microglia activation following SAH resulted in increased caveolin 3 and myeloid diapedesis. A significant increase in BBB markers endothelin 1 and occludin was noted following SAH, but reduced with IL-6 blockade (p < 0.01). CV occurred 5 days post-SAH, but was absent in IL-6 KO mice and mitigated with IL-6 blockade (p < 0.05). IL-6 blockade, and IL-6 KO mitigated effects of SAH on cerebral blood flow (p < 0.05). SAH mice had impaired performance on turn test and poor modified Garcia scores compared to saline and IL-6 blockade. A distinct microglia phenotype was noted day 5 in the SAH group (overlap coefficients r = 0.96 and r = 0.94) for Arg1 and iNOS, which was altered by IL-6 blockade. Day 7, a significant increase in toll-like receptor 4 and Stat3 was noted. This was mitigated by IL-6 blockade and IL-6 KO, which also reduced Caspase 3 (p < 0.05). To confirm the mechanism, we developed a p-STAT3 inhibitor that targets the IL-6 pathway and this reduced NFΚB, TLR4, and nitrotyrosine (p < 0.001). Ventricular dilation and increased Tunel positivity was noted day 9, but resolved by IL-6 blockade (p < 0.05).ConclusionCorrelation between IL-6 and CV has been well documented. We show that a mechanistic connection exists via the p-STAT3 pathway, and IL-6 blockade provides benefit in reducing CV and its consequences mediated by myeloid cell origin diapedesis.Graphical abstract

PLGA-microspheres-carried circGMCL1 protects against Crohn’s colitis through alleviating NLRP3 inflammasome-induced pyroptosis by promoting autophagy

This study aimed to at explore exploring the biological functions of dysregulated circRNA in Crohn’s disease (CD) pathogenesis, with the overarching goal of and providing potential novel therapeutic targets. CircRNA microarray and quantitative real time-polymerase chain reaction (qRT-PCR) analyses were performed to investigate and verify the candidate dysregulated circRNA. The Next, clinical, in vivo, and in vitro studies were performed to investigate explore the biological function and mechanisms of the candidate circRNA in CD. The therapeutic effect of poly (lactic-co-glycolic acid)-microspheres (PLGA MSs)-carried oe-circGMCL1 in experimental colitis models of IL-10 knock-out mice was assessed. CircGMCL1 was identified as the candidate circRNA by microarray and qRT-PCR analyses. Results showed that circGMCL1 expression was negatively correlated with CD-associated inflammatory indices, suggesting that it is a CD-associated circRNA. Microarray and bioinformatics analyses identified miR-124-3p and Annexin 7 (ANXA7) as its downstream mechanisms. The in vitro studies revealed that circGMCL1 mediates its effects on autophagy and NLRP3 inflammasome-mediated pyroptosis in epithelial cells through the ceRNA network. Moreover, the in vivo studies identified the therapeutic effect of PLGA MSs-carried oe-circGMCL1 in experimental colitis models. This study suggests that circGMCL1 protects intestinal barrier function against Crohn’s colitis through alleviating NLRP3 inflammasome-mediated epithelial pyroptosis by promoting autophagy through regulating ANXA7 via sponging miR-124-3p. Therefore, circGMCL1 can serve as a potential biological therapeutic target for Crohn’s colitis.

Fasting-mimicking diet cycles reduce neuroinflammation to attenuate cognitive decline in Alzheimer's models.

The effects of fasting-mimicking diet (FMD) cycles in reducing many aging and disease risk factors indicate it could affect Alzheimer's disease (AD). Here, we show that FMD cycles reduce cognitive decline and AD pathology in E4FAD and 3xTg AD mouse models, with effects superior to those caused by protein restriction cycles. In 3xTg mice, long-term FMD cycles reduce hippocampal Aβ load and hyperphosphorylated tau, enhance genesis of neural stem cells, decrease microglia number, and reduce expression of neuroinflammatory genes, including superoxide-generating NADPH oxidase (Nox2). 3xTg mice lacking Nox2 or mice treated with the NADPH oxidase inhibitor apocynin also display improved cognition and reduced microglia activation compared with controls. Clinical data indicate that FMD cycles are feasible and generally safe in a small group of AD patients. These results indicate that FMD cycles delay cognitive decline in AD models in part by reducing neuroinflammation and/or superoxide production in the brain.

Eosinophils protect against acetaminophen-induced liver injury through cyclooxygenase-mediated IL-4/IL-13 production.

A better understanding of the underlying mechanism of acetaminophen (APAP)-induced liver injury (AILI) remains an important endeavor to develop therapeutic approaches. Eosinophils have been detected in liver biopsies of patients with APAP overdose. We recently demonstrated a profound protective role of eosinophils against AILI; however, the molecular mechanism had not been elucidated. In agreement with our previous data from experiments using genetic deletion of eosinophils, we found that depletion of eosinophils in wild-type (WT) mice by an anti-IL-15 antibody resulted in exacerbated AILI. Moreover, adoptive transfer of eosinophils significantly reduced liver injury and mortality rate in WT mice. Mechanistic studies using eosinophil-specific IL-4/IL-13 knockout mice demonstrated that these cytokines, through inhibiting interferon-γ, mediated the hepatoprotective function of eosinophils. Reverse phase protein array analyses and in vitro experiments using various inhibitors demonstrated that IL-33 stimulation of eosinophils activated p38 mitogen-activated protein kinase (MAPK), and in turn, cyclooxygenases (COX), which triggered NF-κB-mediated IL-4/IL-13 production. In vivo adoptive transfer experiments showed that in contrast to naive eosinophils, those pretreated with COX inhibitors failed to attenuate AILI. The current study revealed that eosinophil-derived IL-4/IL-13 accounted for the hepatoprotective effect of eosinophils during AILI. The data demonstrated that the p38 MAPK/COX/NF-κB signaling cascade played a critical role in inducing IL-4/IL-13 production by eosinophils in response to IL-33.

Eggshell membrane modulates gut microbiota to prevent murine pre-cachexia through suppression of T helper cell differentiation.

BackgroundCachexia is a life‐threatening condition observed in several pathologies, such as cancer or chronic diseases. Interleukin 10 (Il10) gene transfer is known to improve cachexia by downregulating Il6. Here, we used an IL10‐knockout mouse model to simulate cachexia and investigate the effects of eggshell membrane (ESM), a resistant protein, on general pre‐cachexia symptoms, which is particularly important for the development of cachexia therapeutics.MethodsFive‐week‐old male C57BL6/J mice were fed an AIN‐93G powdered diet (WT), and 5‐week‐old male B6.129P2‐Il10 < tm1Cgn>/J (IL10−/−) mice were fed either the AIN‐93G diet (KO) or an 8% ESM‐containing diet (KOE) for 28 weeks. The tissue weight and levels of anaemia‐, blood glucose‐, lipid metabolism‐, and muscular and colonic inflammation‐related biochemical markers were measured. Transcriptomic analysis on liver and colon mucus and proteomic analysis on skeletal muscle were performed. Ingenuity Pathway Analysis was used to identify molecular pathways and networks. Caecal short‐chain fatty acids (SCFAs) were identified using HPLC, and caecal bacteria DNA were subjected to metagenomic analysis. Flow cytometry analysis was performed to measure the CD4+ IL17+ T cells in mesenteric lymph nodes.ResultsThe body weight, weight of gastrocnemius muscle and fat tissues, colon weight/length ratio, plasma HDL and NEFA, muscular PECAM‐1 levels (P < 0.01), plasma glucose and colonic mucosal myeloperoxidase activity (P < 0.05) and T helper (Th) 17 cell abundance (P = 0.071) were improved in KOE mice over KO mice. Proteomic analysis indicated the protective role of ESM in muscle weakness and maintenance of muscle formation (>1.5‐fold). Transcriptomic analysis revealed that ESM supplementation suppressed the LPS/IL1‐mediated inhibition of RXR function pathway in the liver and downregulated the colonic mucosal expression of chemokines and Th cell differentiation‐related markers (P < 0.01) by suppressing the upstream BATF pathway. Analysis of the intestinal microenvironment revealed that ESM supplementation ameliorated the microbial alpha diversity and the abundance of microbiota associated with the degree of inflammation (P < 0.05) and increased the level of total organic acids, particularly of SCFAs such as butyrate (2.3‐fold), which could inhibit Th1 and Th17 production.ConclusionsESM supplementation ameliorated the chief symptoms of cachexia, including anorexia, lean fat tissue mass, skeletal muscle wasting and reduced physical function. ESM also improved colon and skeletal muscle inflammation, lipid metabolism and microbial dysbiosis. These results along with the suppressed differentiation of Th cells could be associated with the beneficial intestinal microenvironment and, subsequently, attenuation of pre‐cachexia. Our findings provide insights into the potential of ESM in complementary interventions for pre‐cachexia prevention.

Abstract 3125: IL-6 contributes to the suppression of T and NK cell anti-tumor activity in EGFR-mutant NSCLC

Abstract Around 10-15% of non-small cell lung cancer (NSCLC) cases in the United States harbor an activating mutation in epidermal growth factor receptor (EGFR) which are initially highly sensitive to treatment EGFR tyrosine kinase inhibitors (TKI) before eventually developing resistance to these agents. Therefore, there is a current unmet clinical need to identify novel treatment options for this patent population. While anti-PD-1/PD-L1 immunotherapy has been effective for many NSCLC patients, EGFR-mutant tumors have response rates of less than 10%. The mechanisms driving resistance to immunotherapy in EGFR-mutant NSCLC are not well understood. We previously reported that IL-6 is highly upregulated in NSCLC cells with acquired resistance to EGFR-TKIs. Because IL-6 is a pleiotropic cytokine known to impact immune populations within the tumor microenvironment, we hypothesized that IL-6 may drive immunosuppression in EGFR mutant NSCLC. Using genetically engineered mouse models (GEMMs) of EGFR-mutant NSCLC with and without IL-6 knockout, we evaluated the effects of IL-6 on the tumor microenvironment. EGFR-mutant mice with knockout of IL-6 had a significantly increased overall survival compared to those with intact-IL-6. Knockout of IL-6 increased total immune infiltration in these tumors as assessed by flow cytometry. Infiltrating T cells from IL-6 knockout mice displayed a smaller population of T helper 17 cells compared to IL-6-expressing tumors. Knockout of IL-6 also increased the population of infiltrating activated CD8 T cells and a reduced T-regulatory cell population. Due to these changes in T cell activity, we wanted to determine any potential synergistic effects of IL-6 blockade used during anti-PD-1 therapy. We observed that combination treatment extended survival in EGFR-mutant NSCLC mice. Corresponding in vitro T cell cytotoxicity assays confirmed that EGFR-TKI resistant cells treated with IL-6 blocking antibody were more sensitive to T cell-mediated killing. Furthermore, infiltration of NK cells was increased in tumors with knockout of IL-6. Infiltrating NK cells found in these IL-6 knockout mice displayed a more activated phenotype as demonstrated by increased expression of NKG2D. Next, we evaluated the effects of IL-6 from conditioned media collected from human EGFR-mutant and TKI-resistant cells lines on human T and NK cells cultured ex vivo. e determined that IL-6 suppressed expression of activation markers including granzyme B and IFN-y on the surface of both T and NK cells. Blockade of IL-6 increased NK-mediated cytotoxic killing of EGFR-TKI resistant cells in vitro. In conclusion, our data indicates that in EGFR-TKI resistance, upregulated IL-6 suppresses T and NK cell cytotoxic potential and drives immunosuppression. Citation Format: Sonia Patel, Monique Nilsson, Yan Yang, Xiaoxing Yu, Fahao Zhang, Alissa Poteete, Xiaoyang Ren, Li Shen, Jing Wang, Xiuning Le, John Heymach. IL-6 contributes to the suppression of T and NK cell anti-tumor activity in EGFR-mutant NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3125.

Prevention of Ulcerative Colitis by Autologous Metabolite Transfer from Colitogenic Microbiota Treated with Lipid Nanoparticles Encapsulating an Anti-Inflammatory Drug Candidate.

Modulating the gut microbiota composition is a potent approach to treat various chronic diseases, including obesity, metabolic syndrome, and ulcerative colitis (UC). However, the current methods, such as fecal microbiota transplantation, carry a risk of serious infections due to the transmission of multi-drug-resistant organisms. Here, we developed an organism-free strategy in which the gut microbiota is modulated ex vivo and microbiota-secreted metabolites are transferred back to the host. Using feces collected from the interleukin-10 (IL-10) knockout mouse model of chronic UC, we found that a drug candidate (M13)-loaded natural-lipid nanoparticle (M13/nLNP) modified the composition of the ex vivo-cultured inflamed gut microbiota and its secreted metabolites. Principal coordinate analysis (PCoA) showed that M13/nLNP shifted the inflamed microbiota composition toward the non-inflamed direction. This compositional modification induced significant changes in the chemical profiles of secreted metabolites, which proved to be anti-inflammatory against in vitro-cultured NF-κβ reporter cells. Further, when these metabolites were orally administered to mice, they established strong protection against the formation of chronic inflammation. Our study demonstrates that ex vivo modulation of microbiota using M13/nLNP effectively reshaped the microbial secreted metabolites and that oral transfer of these metabolites might be an effective and safe therapeutic approach for preventing chronic UC.

Opioid Use in Murine Model Results in Severe Gastric Pathology that May Be Attenuated by Proton Pump Inhibition

Opioids are the gold standard for chronic and acute pain management; however, their consequence on gastric function is relatively understudied. Opioid users have a higher incidence of gastric dysfunction, worse quality of life, increased hospitalizations, and increased use of antiemetic and pain modulator medications. The current study shows that morphine treatment in the murine model results in greater disruption of gastric epithelial cell morphology, increased gastric cell apoptosis, elevated inflammatory cytokines, and matrix metallopeptidase-9 secretion. Morphine treatment also increases gastric acid secretion and causes delays in gastric emptying. Moreover, morphine treatment causes an increase in systemic IL-6 level, which plays an important role in morphine-induced delayed gastric emptying and gastric damage. IL-6 knockout mice show a significant level of reduction in morphine-induced gastric delaying, acid retention, and gastric damage. Thus, morphine-mediated gastric damage is a consequence of the accumulation of acid in the stomach due to increased gastric acid secretion and delayed gastric emptying. Treatment with a proton pump inhibitor resulted in a significant reduction in morphine-induced gastric inflammation, gastric delaying, and improved morphine tolerance. Hence, these studies attribute morphine-mediated induction in gastric acidity and inflammatory cytokines as drivers for morphine-associated gastric pathology and show the therapeutic use of proton pump inhibitors as an inexpensive approach for clinical management of morphine-associated pathophysiology and analgesic tolerance.

Dietary Eggshell Membrane Powder Improves Survival Rate and Ameliorates Gut Dysbiosis in Interleukin-10 Knockout Mice.

Inflammatory bowel disease (IBD) is known to be associated with compositional and metabolic changes in the gut microbiota. The aim of this study was to investigate whether dietary eggshell membrane (ESM) improves survival rate or ameliorates gut dysbiosis in a spontaneous IBD model of interleukin-10 knockout (IL10−/−) mice. Female C57BL/6J wild-type (WT) and IL10−/− mice (KO) were fed an AIN-93G basal diet or an ESM diet (KOE) for 19 weeks. Gut microbiota profiles were analyzed via 16S rRNA sequencing, and short-chain fatty acids in cecal content were analyzed with high-performance liquid chromatography. The results demonstrated that ESM supplementation significantly improved the survival rate and body composition in KO mice. Alpha diversity analysis of the microbiota revealed that ESM supplementation significantly increased gut microbial diversity, which was decreased in IL10−/− mice. The Firmicutes/Bacteroidetes ratio was recovered to a normal level by ESM supplementation, suggesting that ESM helps maintain the compositional balance of the gut microbiota. ESM increased relative abundance of commensal bacterial Ruminococcus and Bacteroidales S24-7 and reduced the abundance of the proinflammatory-related bacterium, Enterobacteriaceae. Additionally, ESM supplementation promoted the production of butyrate in cecal contents and downregulated the expression of proinflammatory genes, including interleukin-1β (Il-1β) and tumor necrosis factor-α (Tnf-α) in IL10−/− mice colon, indicating anti-inflammatory functions. These findings suggest that ESM may be used as a beneficial dietary intervention for IBD.

IL-22 regulates inflammatory responses to agricultural dust-induced airway inflammation

IL-22 is a unique cytokine that is upregulated in many chronic inflammatory diseases, including asthma, and modulates tissue responses during inflammation. However, the role of IL-22 in the resolution of inflammation and how this contributes to lung repair processes are largely unknown. Here, we tested the hypothesis that IL-22 signaling is critical in inflammation resolution after repetitive exposure to agricultural dust. Using an established mouse model of organic dust extract-induced lung inflammation, we found that IL-22 knockout mice have an enhanced response to agricultural dust as evidenced by an exacerbated increase in infiltrating immune cells and lung pathology as compared to wild-type controls. We further identified that, in response to dust, IL-22 is expressed in airway epithelium and in Ym1+ macrophages found within the parenchyma in response to dust. The increase in IL-22 expression was accompanied by increases in IL-22 receptor IL-22R1 within the lung epithelium. In addition, we found that alveolar macrophages in vivo as well as THP-1 cells in vitro express IL-22, and this expression is modulated by dust exposure. Furthermore, subcellular localization of IL-22 appears to be in the Golgi of resting THP1 human monocytes, and treatment with dust extracts is associated with IL-22 release into the cytosolic compartment from the Golgi reservoirs during dust extract exposure. Taken together, we have identified a significant role for macrophage-mediated IL-22 signaling that is activated in dust-induced lung inflammation in mice.

Therapeutic Evaluation of Fecal Microbiota Transplantation in an Interleukin 10-deficient Mouse Model.

With the development of microecology in recent years, the relationship between intestinal bacteria and inflammatory bowel disease (IBD) has attracted considerable attention. Accumulating evidence suggests that dysbiotic microbiota plays an active role in triggering or worsening the inflammatory process in IBD and that fecal microbiota transplantation (FMT) is an attractive therapeutic strategy since transferring a healthy microbiota to IBD patient could restore the appropriate host-microbiota communication. However, the molecular mechanisms are unclear, and the efficacy of FMT has not been very well established. Thus, further studies in animal models of IBD are necessary. In this method, we applied FMT from wild-type C57BL/6J mice to IL-10 deficient mice, a widely used mouse model of colitis. The study elaborates on collecting fecal pellets from the donor mice, making the fecal solution/suspension, administering the fecal solution, and monitoring the disease. We found that FMT significantly mitigated the cardiac impairment in IL-10 knockout mice, underlining its therapeutic potential for IBD management.

Host Immunity Influences the Composition of Murine Gut Microbiota.

The influence of gut microbiota on host immunity is widely studied, and its disturbance has been linked to several immune-mediated disorders. Conversely, whether and how inherently disturbed canonical Th1 (pro-inflammatory) and/or Th2 (anti-inflammatory) immune pathways modify the host microbiome is not sufficiently investigated. Here, we characterized the humoral, cellular, and cytokine immunity, and associated alterations in gut microbiota of naïve wild-type mice (C57BL/6 and BALB/c), and mice with deficiencies in Th2 responses (IL-4Rα and IL-33 knockout mice) or in both Th1 and Th2 responses (NOD scid gamma, NSG mice). A global analysis by de novo clustering of 16S rRNA profiles of the gut microbiota independently grouped wild-type immunocompetent (C57BL/6 and BALB/c), Th2-deficient (IL-4Rα-/- and IL-33-/-), and severely immunodeficient (NSG) mice; where wild-type mice, but not Th2 or severely immunodeficient mice, were enriched in gut bacteria that produce short-chain fatty acids. These include members of phyla Firmicutes, Verrucomicrobia, and Bacteroidetes such as Lactobacillus spp., Akkermansia muciniphila, and Odoribacter spp. Further comparison of the two naïve wild-type mouse strains showed higher microbial diversity (Shannon), primarily linked to higher richness (Chao1), as well as a distinct difference in microbial composition (weighted UniFrac) in BALB/c mice compared to C57BL/6. T-cell and blood cytokine analyses demonstrated a Th1-polarization in naïve adaptive immunity in C57BL/6 animals compared to BALB/c mice, and an expected Th2 deficient cellular response in IL-4Rα-/- and IL-33-/- mice compared to its genetic background BALB/c strain. Together, these data suggest that alterations in the Th1/Th2 balance or a complete ablation of Th1/Th2 responses can lead to major alterations in gut microbiota composition and function. Given the similarities between the human and mouse immune systems and gut microbiota, our finding that immune status is a strong driver of gut microbiota composition has important consequences for human immunodeficiency studies.

Maltodextrin Consumption Impairs the Intestinal Mucus Barrier and Accelerates Colitis Through Direct Actions on the Epithelium.

Food additives are common components of processed foods consumed in a Western diet. In inflammatory bowel disease patients, some diets that exclude food additives improved clinical disease parameters, suggesting a link between food additives and disease pathogenesis. Food additives also enhanced disease severity in mouse colitis models through incompletely described mechanisms. This study examined the mechanisms by which the food additive maltodextrin (MDX) alters the development of colitis in a murine model. Interleukin-10 knockout (IL10KO) mice were fed diets supplemented with MDX or carboxymethyl cellulose (CMC) to determine their impact on colitis onset and severity; microbiome composition, function, and location; colonic immune cell infiltrates; and mucus layer integrity. Primary IL10KO colonic epithelial monolayers were used to dissect the impact of MDX directly on epithelial differentiation and mucus production. MDX or CMC consumption increased the incidence and severity of colitis, as well as decreased microbiome diversity, altered microbial composition, and decreased fecal acetic acid levels. The number of mucus producing cells were decreased in food additive fed mice and resulted in increased microbial proximity to the intestinal epithelium. Additionally, MDX supplementation resulted in crypt hyperplasia and expansion of the HopX+ injury renewal stem cell niche. In primary intestinal epithelial-derived monolayers devoid of microbes and immune cells, MDX exposure decreased goblet cell number and mucus production in association with downregulated expression of the transcription factor Klf4, a marker of terminally differentiated goblet cells. These results suggest MDX disrupts the balance of epithelial cell differentiation and proliferation to contribute to disease pathogenesis through direct and indirect actions on the intestinal epithelial barrier.