Mouse Model Of Inflammation Research Articles

Early and late phases of liver sinusoidal endothelial cell (LSEC) defenestration in mouse model of systemic inflammation

Abstract Background Liver sinusoidal endothelial cells (LSECs) have transcellular pores, called fenestrations, participating in the bidirectional transport between the vascular system and liver parenchyma. Fenestrated LSECs indicate a healthy phenotype of liver while loss of fenestrations (defenestration) in LSECs is associated with liver pathologies. Methods We introduce a unique model of systemic inflammation triggered by the deletion of Mcpip1 in myeloid leukocytes (Mcpip1fl/flLysMCre) characterised by progressive alterations in LSEC phenotype. We implement multiparametric characterisation of LSECs by using novel real-time atomic force microscopy supported with scanning electron microscopy and quantitative fluorescence microscopy. In addition, we provide genetic profiling, searching for characteristic genes encoding proteins that might be connected with the structure of fenestrations. Results We demonstrate that LSECs in Mcpip1fl/flLysMCre display two phases of defenestration: the early phase, with modest defenestration that was fully reversible using cytochalasin B and the late phase, with severe defenestration that is mostly irreversible. By thorough analysis of LSEC porosity, elastic modulus and actin abundance in Mcpip1fl/flLysMCre and in response to cytochalasin B, we demonstrate that proteins other than actin must be additionally responsible for inducing open fenestrations. We highlight several genes that were severely affected in the late but not in the early phase of LSEC defenestration shedding a light on complex structure of individual fenestrations. Conclusions The presented model of LSEC derived from Mcpip1fl/flLysMCre provides a valuable reference for developing novel strategies for LSEC refenestration in the early and late phases of liver pathology.

Mycophenolate Mofetil, an Inhibitor of Inosine Monophosphate Dehydrogenase, and Tofacitinib, a Janus Kinase Inhibitor, Attenuate Airway Inflammation and Hyperresponsiveness in a Mouse Model of Allergic Asthma

Treatment-resistant asthma remains an unresolved clinical problem and a challenge for current medical science. Consequently, there is a growing and urgent need to develop novel or alternative therapeutic options for the treatment of asthma. The research problem raised in this study was to assess and compare mycophenolate mofetil (MMF), an inhibitor of inosine monophosphate dehydrogenase, and tofacitinib (TFB), a Janus kinase inhibitor, for anti-asthmatic properties, and consequently to determine whether these agents may have potential as alternative options for treatment of allergic asthma. For this purpose, we assessed the effect of administration of MMF and TFB on the development of a mouse model of allergic airway inflammation (AAI) and accompanying CD4+ (cluster of differentiation 4) T-cell immune response in the lung-draining mediastinal lymph nodes (MLNs) and lungs, i.e., in the inductive and effector sites, respectively, of the immune response underlying the development of allergic asthma. The results from a histopathological scoring system demonstrated that the administration of MMF and TFB did not prevent or abolish ovalbumin-induced AAI, but strongly attenuated its severity. The pulmonary function tests revealed that the treatment with MMF and TFB significantly reduced methacholine-induced bronchoconstriction. These results indicate that the treatment with TFB and MMF attenuated the development of ovalbumin-induced AAI. The magnitude of the anti-asthmatic effect was comparable between both agents. The study revealed that the impairment of the clonal expansion of effector CD4+ T cells in the MLNs is a critical event in the mechanism underlying the anti-asthmatic effect of MMF and TFB. Apart from this, the findings of the study strongly suggest that the suppression of the interleukin-33/suppression of tumorigenicity-2 signaling pathway may constitute an additional mechanism responsible for producing this effect. In turn, the results indicate that the anti-asthmatic action induced by the studied agents is not mediated by the generation of forkhead box protein 3-expressing CD4+ regulatory T cells. Clinical implication of the results: the results suggest that MMF and TFB may exert anti-asthmatic action, and thus they may be considered therapeutic options for the treatment of allergic asthma cases resistant to conventional/existing treatment.

Preclinical characterization of MTX-101: a novel bispecific CD8 Treg modulator that restores CD8 Treg functions to suppress pathogenic T cells in autoimmune diseases

IntroductionRegulatory CD8 T cells (CD8 Treg) are responsible for the selective killing of self-reactive and pathogenic CD4 T cells. In autoimmune disease, CD8 Treg may accumulate in the peripheral blood but fail to control the expansion of pathogenic CD4 T cells that subsequently cause tissue destruction. This CD8 Treg dysfunction is due in part to the expression of inhibitory killer immunoglobulin-like receptors (KIR; KIR2DL isoforms [KIR2DL1, KIR2DL2, and KIR2DL3]); these molecules serve as autoimmune checkpoints and limit CD8 Treg activation.MethodsHere we describe the pre-clinical characterization of MTX-101, a bispecific antibody targeting inhibitory KIR and CD8. Using human peripheral blood mononuculear cells (PBMC) derived from healthy donors and autoimmune patients, humanized mouse models, and human derived tissue organoids, we evaluated the molecular mechanisms and functional effects of MTX-101.ResultsBy binding to KIR, MTX-101 inhibited KIR signaling that can restore CD8 Treg ability to eliminate pathogenic CD4 T cells. MTX-101 bound and activated CD8 Treg in human peripheral blood mononuclear cells (PBMC), resulting in increased CD8 Treg cytolytic capacity, activation, and prevalence. Enhancing CD8 Treg function with MTX-101 reduced pathogenic CD4 T cell expansion and inflammation, without increasing pro-inflammatory cytokines or activating immune cells that express either target alone. MTX-101 reduced antigen induced epithelial cell death in disease affected tissues, including in tissue biopsies from individuals with autoimmune disease (i.e., celiac disease, Crohn’s disease). The effects of MTX-101 were specific to autoreactive CD4 T cells and did not suppress responses to viral and bacterial antigens. In a human PBMC engrafted Graft versus Host Disease (GvHD) mouse model of acute inflammation, MTX-101 bound CD8 Treg and delayed onset of disease. MTX-101 induced dose dependent binding, increased prevalence and cytolytic capacity of CD8 Treg, as well as increased CD4 T cell death. MTX-101 selectively bound CD8 Treg without unwanted immune cell activation or increase of pro-inflammatory serum cytokines and exhibited an antibody-like half-life in pharmacokinetic and exploratory tolerability studies performed using IL-15 transgenic humanized mice with engrafted human lymphocytes, including CD8 Treg at physiologic ratios.ConclusionCollectively, these data support the development of MTX-101 for the treatment of autoimmune diseases.

Piezo1 restrains proinflammatory response but is essential in T cell-mediated immunopathology.

Piezo1 is a mechanosensitive, nonselective Ca2+ channel which is broadly expressed in CD4+ T cells. Using lineage-specific Piezo1 knockout mice (Piezo1cKO), we show that loss of Piezo1 in CD4+ T cells significantly increased IFNγ and IL-17 production in vitro under TH1 and TH17 polarizing conditions, respectively. Despite their intrinsic proinflammatory phenotype, Piezo1cKO T cells are incapable of establishing disease in vivo in three separate adoptive transfer (AT) T cell-mediated inflammatory mouse models, including experimental autoimmune encephalomyelitis, inflammatory bowel disease (IBD), and graft versus-host disease. These phenomena coincided with a decreased effector memory (CD44hiCD62Llo) CD4+ T cell pool derived from donor Piezo1cKO T cells, an observation that is related to intrinsic T-cell fitness, as co-transfer IBD mouse model revealed a deficiency in the CD4+ effector memory population derived only from the naïve Piezo1cKO but not co-infused Piezo1WT CD4+ T cell source. Taken together, our results support Piezo1 as restraining proinflammatory T cell differentiation while contributing to the generation and persistence of the effector memory pool during CD4+ T cell-mediated immunopathology.

Impact of Dual-coated Silver Nanoparticle and Antibiotic Sutures on Wound Healing in Inflammatory Mouse Models

ABSTRACT Background: The use of silver nanoparticles (AgNPs) in biomedicine has emerged in a big way owing to its antibacterial and anti-inflammatory properties. We hypothesize that combining the AgNPs with antibiotics for coating sutures will enhance the antibacterial property of sutures with the added advantage of the immunomodulatory effect of AgNPs on tissue healing. Materials and Methods: Polyglactin sutures were coated with AgNPs using the dip-coating method. The uniform coating and morphology of AgNPs on the suture surface were confirmed using scanning electron microscopy (SEM). Each type of suture – polyglactin plain, antibiotic coated (Triclosan), AgNP coated, and dually coated (antibiotic and AgNP) – was assessed for their antibacterial properties against Gram-positive bacteria, Gram-negative bacteria, and anaerobes. These sutures were utilized in an abdominal and systemic inflammatory mice model for ileal anastomosis. The intestinal tissue was evaluated for acute and chronic inflammation and collagen deposition to assess the healing and inflammatory response. Results: The SEM and energy dispersive X-ray analysis showed successful coating of AgNPs on plain and antibiotic-coated sutures. In comparison with the other groups, the dually coated suture had the best in vitro antibacterial efficacy. The AgNP-coated sutures were able to decrease both acute and chronic inflammatory cell infiltration, but the collagen synthesis and deposition were enhanced. Conclusion: AgNPs can be coated on Polyglactin suture either alone or in combination with antibiotics with preserved antibacterial effects. The dual coating of sutures gives a synergistic antibacterial effect. The AgNP diminishes immune response in the presence of preserved extracellular matrix generation.

Senolytic treatment diminishes microglia and decreases severity of experimental autoimmune encephalomyelitis

BackgroundThe role of senescence in disease contexts is complex, however there is considerable evidence that depletion of senescent cells improves outcomes in a variety of contexts particularly related to aging, cognition, and neurodegeneration. Much research has shown previously that inflammation can promote cellular senescence. Microglia are a central nervous system innate immune cell that undergo senescence with aging and during neurodegeneration. The contribution of senescent microglia to multiple sclerosis, an inflammatory neurodegenerative disease, is not clear, but microglia are strongly implicated in chronic active lesion pathology, tissue injury, and disease progression. Drugs that could specifically eliminate dysregulated microglia in multiple sclerosis are therefore of great interest to the field.ResultsA single-cell analysis of brain tissue from mice subjected to experimental autoimmune encephalomyelitis (EAE), a mouse model of CNS inflammation that models aspects of multiple sclerosis (MS), identified microglia with a strong transcriptional signature of senescence including the presence of BCL2-family gene transcripts. Microglia expressing Bcl2l1 had higher expression of pro-inflammatory and senescence associated genes than their Bcl2l1 negative counterparts in EAE, suggesting they may exacerbate inflammation. Notably, in human single-nucleus sequencing from MS, BCL2L1 positive microglia were enriched in lesions with active inflammatory pathology, and likewise demonstrated increased expression of immune genes suggesting they may be proinflammatory and contribute to disease processes in chronic active lesions. Employing a small molecule BCL2-family inhibitor, Navitoclax (ABT-263), significantly reduced the presence of microglia and macrophages in the EAE spinal cord, suggesting that these cells can be targeted by senolytic treatment. ABT-263 treatment had a profound effect on EAE mice: decreasing motor symptom severity, improving visual acuity, promoting neuronal survival, and decreasing white matter inflammation.ConclusionThese results support the hypothesis that microglia and macrophages exhibit transcriptional features of cellular senescence in EAE and MS, and that microglia expressing Bcl2l1 demonstrate a proinflammatory signature that may exacerbate inflammation resulting in negative outcomes in neuroinflammatory disease. Depleting microglia and macrophages using a senolytic results in robust improvement in EAE disease severity, including across measures of neurodegeneration, inflammation, and demyelination, and may therefore represent a novel strategy to address disease progression in multiple sclerosis.

Massively Parallel Screening of Toll/Interleukin-1 Receptor (TIR)-Derived Peptides Reveals Multiple Toll-Like Receptors (TLRs)-Targeting Immunomodulatory Peptides.

Toll-like receptors (TLRs) are critical regulators of the immune system, and altered TLR responses lead to a variety of inflammatory diseases. Interference of intracellular TLR signaling, which is mediated by multiple Toll/interleukin-1 receptor (TIR) domains on all TLRs and TLR adapters, is an effective therapeutic strategy against immune dysregulation. Peptides that inhibit TIR-TIR interactions by fragmenting interface residues have potential as therapeutic decoys. However, a systematic method for discovering TIR-targeting moieties has been elusive, limiting exploration of the vast, unsequenced space of the TIR domain family. A comprehensive parallel screening method is developed to uncover novel TIR-binding peptides derived from previously unexplored surfaces on a wide range of TIR domains. A large peptide library is constructed, named TIR surfacesome, by tiling surface sequences of the large TIR domain family and screening against MALTIR and MyD88TIR, TIRs of two major TLR adaptor proteins, resulting in the discovery of hundreds of TIR-binding peptides. The selected peptides inhibited TLR signaling and demonstrated anti-inflammatory effects in macrophages, and therapeutic potential in mouse inflammatory models. This approach may facilitate the development of TLR-targeted therapeutics.

Acceptable daily intake of aspartame aggravates enteritis pathology and systemic inflammation in colitis mouse model.

In this study, a dextran sodium sulfate-induced ulcerative colitis model in C57BL/6 mice was used to explore the effect of acceptable daily intake (ADI) of aspartame on inflammation in colonic tissues. The effects of aspartame on the inflammatory state of the colon in mice were comprehensively evaluated by comparing the body weight, colon length/colon length index, splenic index, disease activity index (DAI) score, histological activity index (HAI) score, the expression levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, claudin-3, and occludin, the infiltration characteristics of macrophage and neutrophil and the composition of the gut microbiota in the control group, aspartame group, ulcerative colitis model group, and aspartame + ulcerative colitis group. We demonstrated that, in a mouse model of dextran sulfate-induced ulcerative colitis, ADI of aspartame caused a significant decrease in body weight, colon length/colon length index, DAI scores, and expression levels of the proteins claudin-3 and occludin. Moreover, ADI of aspartame caused an increase in the splenic index, HAI scores, the levels of proinflammatory factors TNF-α, IL-1β, and IL-6 both in intestinal tissue and serum and infiltration of macrophages and neutrophils in colon tissues. These results showed that ADI of aspartame promoted intestinal pathology and systemic inflammation in a mouse model of colitis.

Spatial transcriptomics of meningeal inflammation reveals inflammatory gene signatures in adjacent brain parenchyma.

While modern high efficacy disease modifying therapies have revolutionized the treatment of relapsing-remitting multiple sclerosis, they are less effective at controlling progressive forms of the disease. Meningeal inflammation is a recognized risk factor for cortical gray matter pathology which can result in disabling symptoms such as cognitive impairment and depression, but the mechanisms linking meningeal inflammation and gray matter pathology remain unclear. Here, we performed magnetic resonance imaging (MRI)-guided spatial transcriptomics in a mouse model of autoimmune meningeal inflammation to characterize the transcriptional signature in areas of meningeal inflammation and the underlying brain parenchyma. We found broadly increased activity of inflammatory signaling pathways at sites of meningeal inflammation, but only a subset of these pathways active in the adjacent brain parenchyma. Subclustering of regions adjacent to meningeal inflammation revealed the subset of immune programs induced in brain parenchyma, notably complement signaling and antigen processing/presentation. Trajectory gene and gene set modeling analysis confirmed variable penetration of immune signatures originating from meningeal inflammation into the adjacent brain tissue. This work contributes a valuable data resource to the field, provides the first detailed spatial transcriptomic characterization in a model of meningeal inflammation, and highlights several candidate pathways in the pathogenesis of gray matter pathology.

Spatial transcriptomics of meningeal inflammation reveals inflammatory gene signatures in adjacent brain parenchyma

While modern high efficacy disease modifying therapies have revolutionized the treatment of relapsing-remitting multiple sclerosis, they are less effective at controlling progressive forms of the disease. Meningeal inflammation is a recognized risk factor for cortical gray matter pathology which can result in disabling symptoms such as cognitive impairment and depression, but the mechanisms linking meningeal inflammation and gray matter pathology remain unclear. Here, we performed magnetic resonance imaging (MRI)-guided spatial transcriptomics in a mouse model of autoimmune meningeal inflammation to characterize the transcriptional signature in areas of meningeal inflammation and the underlying brain parenchyma. We found broadly increased activity of inflammatory signaling pathways at sites of meningeal inflammation, but only a subset of these pathways active in the adjacent brain parenchyma. Subclustering of regions adjacent to meningeal inflammation revealed the subset of immune programs induced in brain parenchyma, notably complement signaling and antigen processing/presentation. Trajectory gene and gene set modeling analysis confirmed variable penetration of immune signatures originating from meningeal inflammation into the adjacent brain tissue. This work contributes a valuable data resource to the field, provides the first detailed spatial transcriptomic characterization in a model of meningeal inflammation, and highlights several candidate pathways in the pathogenesis of gray matter pathology.

Preclinical Safety Assessment of Deferoxamine-preconditioned Canine Adipose Tissue-derived Mesenchymal Stem Cells.

In the pursuit of translating stem cell therapy technology into clinical practice, ensuring the safety and efficacy of treatments is paramount. Despite advancements, the effectiveness of stem cell applications often falls short of clinical requirements. This study aimed to address the challenge of limited efficacy by investigating the safety and effectiveness of canine adipose tissue-derived mesenchymal stem cells (cATMSCs) preconditioned with deferoxamine (DFO). Different concentrations of DFO were used to evaluate its impact on cATMSC activity. The therapeutic potential of these preconditioned cells was validated using a mouse model of systemic inflammation. Comprehensive evaluations, including clinical hematological and radiological assessments before and after intravenous injection of preconditioned cells were conducted. The study showed a notable reduction in inflammatory markers and an overall decrease in the inflammatory response in the mouse model. The data collected from the clinical hematological and radiological assessments provided essential insights. This study lays the groundwork for the future clinical deployment of DFO-preconditioned cATMSCs, demonstrating their potential to improve the efficacy and safety of stem cell therapies.

Amelioration of Systemic Amyloidosis by Blocking IL-17A and Not by IL-17F, and Arteriosclerosis by Blocking Both IL-17A and IL-17F in an Inflammatory Skin Mouse Model

There are comorbidities and complications in atopic dermatitis and psoriasis that often occur after the appearance of skin inflammation. Statistically, data show that patients with psoriasis and atopic dermatitis have a shorter life expectancy than patients without psoriatic dermatitis, due to the occurrence of arteriosclerosis, myocardial infarction, and cerebral infarction. Many types of skin inflammation are treated with various antibody preparations, and marked improvement in patients’ quality of life can be achieved. The next theme is to understand the pathogenesis of arteriosclerosis, myocardial infarction, stroke, and other complications associated with dermatitis and to find treatments and drugs to reduce their occurrence. The skin, a crucial immune organ, generates large amounts of inflammatory cytokines in response to various stimuli, leading to systemic inflammation and potential damage to internal organs. The link between inflammatory skin conditions like psoriasis and atopic dermatitis with serious health complications such as vascular disorders and systemic amyloidosis has been increasingly recognized. In psoriasis, biological treatments targeting Interleukin (IL)-17A, a key cytokine, have shown promise in reducing cardiovascular risks. Recent developments include treatments that target both IL-17A and IL-17F in the psoriasis field, though each cytokine’s impact on internal organ damage is still under debate. Among visceral complications secondary to dermatitis, systemic amyloidosis and atherosclerosis have been reported to be controlled by suppressing IL-17 in the early stages of dermatitis. Still, it remains unclear whether suppressing IL-17 prevents organ damage in the late stages of persistent severe dermatitis. A study using a long-lasting dermatitis mouse model that overexpressed human caspase-1 in keratinocytes (Kcasp1Tg) investigated the effects of deleting IL-17A and IL-17F on visceral complications. Cross-mating Kcasp1Tg with IL-17A-, IL-17F-, and IL-17AF-deficient mice assessed the skin and visceral organs histologically, and RT-PCR analysis of aortic sclerosis markers was performed. Despite less improvement in dermatitis, deletion of IL-17A in Kcasp1Tg mice showed promising results in reducing multiple organ amyloidosis. On the other hand, the effect was observed in both IL-17A and IL-17F deleted mice for aortic sclerosis. The inhibition of IL-17A and IL-17F was suggested to reduce the risk of developing comorbidities in internal organs. IL-17A and IL-17F were found to act similarly or produce very different results, depending on the organ.

Progranulin derivative attenuates lung neutrophilic infiltration from diesel exhaust particle exposure.

Air pollutants, such as diesel exhaust particles (DEPs), induce respiratory disease exacerbation with neutrophilic infiltration. Progranulin (PGRN), an epithelial cell and macrophage-derived secretory protein, is associated with neutrophilic inflammation. PGRN is digested into various derivatives at inflammatory sites and is involved in several inflammatory processes. PGRN and its derivatives likely regulate responses to DEP exposure in allergic airway inflammation. To investigate the role of PGRN and its derivatives in the regulation of responses to DEP exposure in allergic airway inflammation. A murine model of allergic airway inflammation was generated in PGRN-deficient mice, and they were simultaneously exposed to DEP followed by intranasal administration of full-length recombinant PGRN (PGRN-FL) and a PGRN-derived fragment (FBAC). Inflammatory status was evaluated by bronchoalveolar lavage fluid and histopathologic analyses. Human bronchial epithelial cells were stimulated with DEPs and house dust mites (HDMs), and the effect of FBAC treatment was evaluated by assessing various intracellular signaling molecules, autophagy markers, inflammatory cytokines, and intracellular oxidative stress. DEP exposure exaggerated neutrophilic inflammation, enhanced IL-6 and CXCL15 secretions, and increased oxidative stress in the murine model; this effect was greater in PGRN-deficient mice than in wild-type mice. The DEP-exposed mice with PGRN-FL treatment revealed no change in neutrophil infiltration and higher oxidative stress status in the lungs. On the contrary, FBAC administration inhibited neutrophilic infiltration and reduced oxidative stress. In human bronchial epithelial cells, DEP and HDM exposure increased intracellular oxidative stress and IL-6 and IL-8 secretion. Decreased nuclear factor erythroid 2-related factor 2 (Nrf2) expression and increased phosphor-p62 and LC3B expression were also observed. FBAC treatment attenuated oxidative stress from DEP and HDM exposure. FBAC reduced neutrophilic inflammation exaggerated by DEP exposure in a mouse model of allergic airway inflammation by reducing oxidative stress. PGRN and PGRN-derived proteins may be novel therapeutic agents in attenuating asthma exacerbation induced by air pollutant exposure.

Novel TSPO Ligand 2-Cl-MGV-1 Can Counteract Lipopolysaccharide Induced Inflammatory Response in Murine RAW264.7 Macrophage Cell Line and Lung Models.

We assessed the anti-inflammatory activity of the TSPO ligand 2-Cl-MGV-1. Lipopolysaccharide (LPS) was used to induce inflammatory response in a murine RAW264.7 macrophage model (LPS: 100 ng/mL) and a mouse model (C57BL/6) of lung inflammation (LPS: 5 mg/kg). In the macrophage model, the presence of 2-Cl-MGV-1 (25 µM) caused the LPS-induced elevation in nitrite levels to decrease by 70% (p < 0.0001) and interleukin (IL)-6 by 50% (p < 0.05). In the mouse model, 2-Cl-MGV-1, administered 30 min before, or co-administered with, an LPS injection, significantly inhibited the elevation in serum IL-5 levels (both by 65%; p < 0.001 and p < 0.01, respectively). 2-Cl-MGV-1 administration to mice 30 min before LPS injection and 1 h thereafter significantly inhibited the elevation in IL-1β serum levels (both by 63%, p < 0.005). IL-6 elevation was inhibited by 73% (p < 0.005) when 2-Cl-MGV-1 was administered 30 min before LPS, by 60% (p < 0.05) when co-administered with LPS, and by 64% (p < 0.05) when administered 1 h after LPS. All cytokine assessments were conducted 6 h post LPS injection. Histological analyses showed decreased leukocyte adherence in the lung tissue of the ligand-treated mice. 2-Cl-MGV-1 administration 30 min prior to exposure to LPS inhibited inflammation-induced open field immobility. The beneficial effect of 2-Cl-MGV-1 suggests its potential as a therapeutic option for inflammatory diseases.

Intracellular osteopontin potentiates the immunosuppressive activity of mesenchymal stromal cells

IntroductionMesenchymal stromal cell (MSC)-based cell therapy is a promising approach for various inflammatory disorders based on their immunosuppressive capacity. Osteopontin (OPN) regulates several cellular functions including tissue repair, bone metabolism and immune reaction. However, the biological function of OPN in regulating the immunosuppressive capacity of MSCs remains elusive.ObjectivesThis study aims to highlight the underlying mechanism of the proinflammatory cytokines affect the therapeutic ability of MSCs through OPN.MethodsMSCs in response to the proinflammatory cytokines were collected to determine the expression profile of OPN. In vitro T-cell proliferation assays and gene editing were performed to check the role and mechanisms of OPN in regulating the immunosuppressive capacity of MSCs. Inflammatory disease mouse models were established to evaluate the effect of OPN on improving MSC-based immunotherapy.ResultsWe observed that OPN, including its two isoforms iOPN and sOPN, was downregulated in MSCs upon proinflammatory cytokine stimulation. Interestingly, iOPN, but not sOPN, greatly enhanced the immunosuppressive activity of MSCs on T-cell proliferation and thus alleviated the inflammatory pathologies of hepatitis and colitis. Mechanistically, iOPN interacted with STAT1 and mediated its deubiquitination, thereby inducing the master immunosuppressive mediator inducible nitric oxide synthase (iNOS) in MSCs. In addition, iOPN expression was directly downregulated by activated STAT1, which formed a negative feedback loop to restrain MSC immunosuppressive capacity.ConclusionOur findings demonstrated that iOPN expression modulation in MSCs is a novel strategy to improve MSC-based immunotherapy.

A pH-sensitive opioid does not exhibit analgesic tolerance in a mouse model of colonic inflammation.

Tolerance to the analgesic effects of opioids and resultant dose escalation is associated with worsening of side effects and greater addiction risk. Here, we compare the development of tolerance to the conventional opioid fentanyl with a novel pH-sensitive μ-opioid receptor (MOR) agonist, (±)-N-(3-fluoro-1-phenethylpiperidine-4-yl)-N-phenyl propionamide (NFEPP) that is active only in acidic inflammatory microenvironments. An opioid tolerance model was developed in male C57BL/6 mice, with and without dextran sulphate sodium colitis, using increasing doses of either fentanyl or NFEPP over 5 days. Visceral nociception was assessed in vivo by measuring visceromotor responses (VMRs) to noxious colorectal distensions and in vitro measuring colonic afferent nerve activity of mesenteric nerves and performing patch-clamp recordings from isolated dorsal root ganglia neurons. Somatic thermal nociception was tested using a tail immersion assay. Cardiorespiratory effects were analysed by pulse oximeter experiments. VMRs and tail immersion tests demonstrated tolerance to fentanyl, but not to NFEPP in colitis mice. Cross-tolerance also occurred to fentanyl, but not to NFEPP. The MOR agonist DAMGO inhibited colonic afferent nerve activity in colitis mice exposed to chronic NFEPP, but not those from fentanyl-treated mice. Similarly, in patch-clamp recordings from isolated dorsal root ganglia neurons, DAMGO inhibited neurons from NFEPP-, but not fentanyl-treated mice. NFEPP did not exhibit tolerance in an inflammatory pain model, unlike fentanyl. Consequently, dose escalation to maintain analgesia during an evolving inflammation could be avoided, mitigating the potential risk of side effects.

Gene expression changes in mouse lung induced by subacute inhalation of PM10-rich particulate matter

Introduction Particulate matter (PM) air pollution is associated with an increased incidence of lung diseases, but the underlying mechanisms have not been fully elucidated. In this study, a mouse model of subacute lung inflammation was employed to investigate the cellular responses and gene expression changes induced by exposure to natural ambient air pollution. Methods C57BL/6J mice were exposed to road dust (primarily PM10) at 150 µg/m³ for 21 days (8 h/day) through a nose-only inhalation exposure system. Lung tissues were analyzed for the expression of proinflammatory signaling, oxidative stress, and fibrosis markers. RNA-sequencing analysis was conducted to identify differentially expressed genes (DEGs). A gene ontology over-representation analysis was performed to identify the altered genetic pathways. Results Elevated levels of proinflammatory cytokines, including IL-1β, IL-6, and TNF-α, and an increase in phosphorylated MAPK were determined in the road dust exposure group compared to the control group. Histopathological examinations revealed more severe lung inflammation and damage in the exposed mice, including fibrosis and bronchiolar hyperplasia. Gene expression profiling identified 108 DEGs, with decreases in most except genes such as Krt15 and Reg3g. The protein–protein interaction network analysis together with text-mining identified 18 key hub genes, associated with fatty acid oxidation, lipid metabolism, and peroxisomes. Conclusion This study identified key genes, signaling pathways, and cellular responses in mouse lung affected by road dust exposure. These findings contribute to a deeper understanding of the transcriptional and cellular responses induced by subacute exposure to the PM in road dust.

A Nitric Oxide-Sensing T1 Contrast Agent for In Vivo Molecular MR Imaging of Inflammatory Disease.

Nitric oxide (NO) is a signaling molecule that not only appears in the very early stage of inflammatory disease but also persists in chronic conditions. Its detection in vivo can, therefore, potentially enable early disease detection and treatment monitoring. Due to its transient nature and low abundance, however, noninvasive and deep-tissue imaging of NO dynamics is challenging. In this study, we present a magnetic resonance imaging (MRI) contrast agent based on a manganese porphyrin for specific imaging of NO. This agent is activated by NO, binds to tissue protein, accumulates so long as NO is actively produced, and confers a substantial bright contrast on T1-weighted MRI. In vitro tests confirm the specificity of activation by NO over other reactive oxygen or nitrogen species, absence of inflammation induced by the contrast agent, and sensitivity to NO levels in the tens of micromolar. In vivo demonstration in a mouse model of stress-induced acute myocardial inflammation revealed an over 2.2-times increase in T1 reduction in the inflamed heart compared to a healthy heart. This new NO-activatable T1 contrast agent holds the potential to provide early diagnosis of inflammatory disease, characterize different stages of inflammation, and ultimately guide the design of novel anti-inflammation therapeutics.

The molecular mechanism of berberine affecting psoriasis skin inflammation by regulating keratinocyte pyroptosis via the p38 MAPK/NF-κB pathway.

Berberine (BBR), a Rhizoma Coptis-sourced isoquinoline alkaloid, is an effective drug for psoriasis treatment with its therapeutic mechanism remaining unclear. We delved into the mechanism of BBR affecting psoriatic skin inflammation by regulating keratinocyte pyroptosis. A psoriasis-like skin inflammation mouse model was induced by imiquimod (IMQ) and treated with BBR and a p38 activator anisomycin. Human epidermal keratinocytes (HEKs) were stimulated with five chemokines (M5) [interleukin (IL)-17A, IL-22A, oncostatin M, tumor necrosis factor-α, IL-1α] to simulate psoriasis immune microenvironment, then treated with BBR and anisomycin. Psoriasis skin lesions, skin tissue damage, cell viability and death, and gasdermin D-N (GSDMD-N) and NOD-like receptor protein 3 (NLRP3) positive cell numbers were assessed. The p38 mitogen-activated protein kinase (MAPK)/nuclear factor-kappa B (NF-κB) pathway and levels of the NLRP3/GSDMD pathway-related proteins and inflammatory factors were determined. BBR alleviated M5-induced HEK pyroptosis by inactivating NLRP3 inflammasomes. BBR inhibited the p38 MAPK/NF-κB pathway, and its effects on HEKs were partly averted by activating the p38 MAPK/NF-κB pathway. BBR repressed NLRP3 inflammasome activation and pyroptosis by inhibiting the p38 MAPK/NF-κB pathway. Collectively, BBR suppressed keratinocyte NLRP3/GSDMD pathway pyroptosis by suppressing the p38 MAPK/NF-κB pathway, thereby affecting psoriasis skin inflammation.

Structure-function analysis of time-resolved immunological phases in metabolic dysfunction-associated fatty liver disease (MASH) comparing the NIF mouse model to human MASH

Metabolic dysfunction-associated steatohepatitis (MASH) is a common but frequently unrecognized complication of obesity and type 2 diabetes. The association between these conditions is multifaceted and involves complex interactions between metabolic, inflammatory, and genetic factors. Here we assess the underlying structural and molecular processes focusing on the immunological phase of MASH in the nonobese inflammation and fibrosis (NIF) mouse model and compare it to the human disease as well as other murine models. Histopathology together with synchrotron-radiation-based x-ray micro-computed tomography (SRµCT) was used to investigate structural changes within the hepatic sinusoids network in the NIF mouse in comparison to patients with different severities of MASH. A time-course, bulk RNA-sequencing analysis of liver tissue from NIF mice was performed to identify the dynamics of key processes associated with the pathogenesis. Transcriptomics profiling of the NIF mouse revealed a gradual transition from an initially reactive inflammatory response to a regenerative, pro-fibrotic inflammatory response suggesting new avenues for treatment strategies that focus on immunological targets. Despite the lack of metabolic stress induced liver phenotype, a large similarity between the NIF mouse and the immunological phase of human MASH was detected. The translational value was further supported by the comparative analyses with MASH patients and additional animal models. Finally, the impact of diets known to induce metabolic stress, was explored in the NIF mouse. An obesogenic diet was found to induce key physiological, metabolic, and histologic changes akin to those observed in human MASH.