Administration Of IL-1β Research Articles

Gasdermin D promotes development of intestinal tumors through regulating IL-1β release and gut microbiota composition

The interplay between gut microbiota and host is crucial for maintaining host health. When this balance is broken, various diseases can arise, including colorectal cancer (CRC). However, the mechanism by which gut microbiota and host interactions mediate CRC development remains unclear. Here, we found that Gasdermin D (GSDMD), an inflammasome effector responsible for forming membrane pores to mediate cell pyroptosis, was upregulated in both human and mouse intestinal tumor samples. GSDMD deficiency significantly suppressed intestinal tumor development in Apcmin/+ mice, a spontaneous CRC mouse model. Apcmin/+Gsdmd−/− mice exhibited reduced IL-1β release in the intestine, and the administration of recombinant mouse IL-1β partially restored intestinal tumor development in Apcmin/+Gsdmd−/− mice. Moreover, 16s rRNA sequencing showed a substantial increase in Lactobacillus abundance in the feces of Apcmin/+Gsdmd−/− mice compared to Apcmin/+ mice. Concurrently, Kynurenine (Kyn), a metabolite derived from host tryptophan (Trp) metabolism, was significantly decreased in the feces of Apcmin/+Gsdmd−/− mice, as shown by metabolite analysis. Additionally, Kyn levels were inversely correlated with Lactobacillus abundance. Furthermore, the administration of exogenous Kyn also promoted intestinal tumor development in Apcmin/+Gsdmd−/− mice. Thus, GSDMD promotes spontaneous CRC development through increasing IL-1β release and Kyn production. Our data suggest an association between GSDMD, gut microbiota, the host Trp/Kyn pathway, and CRC development.

Single-cell analysis reveals lasting immunological consequences of influenza infection and respiratory immunization in the pig lung.

The pig is a natural host for influenza viruses and integrally involved in virus evolution through interspecies transmissions between humans and swine. Swine have many physiological, anatomical, and immunological similarities to humans, and are an excellent model for human influenza. Here, we employed single cell RNA-sequencing (scRNA-seq) and flow cytometry to characterize the major leukocyte subsets in bronchoalveolar lavage (BAL), twenty-one days after H1N1pdm09 infection or respiratory immunization with an adenoviral vector vaccine expressing hemagglutinin and nucleoprotein with or without IL-1β. Mapping scRNA-seq clusters from BAL onto those previously described in peripheral blood facilitated annotation and highlighted differences between tissue resident and circulating immune cells. ScRNA-seq data and functional assays revealed lasting impacts of immune challenge on BAL populations. First, mucosal administration of IL-1β reduced the number of functionally active Treg cells. Second, influenza infection upregulated IFI6 in BAL cells and decreased their susceptibility to virus replication in vitro. Our data provide a reference map of porcine BAL cells and reveal lasting immunological consequences of influenza infection and respiratory immunization in a highly relevant large animal model for respiratory virus infection.

Abstract 4989: Targeting IL-1β mitigates radiation induced MDSC expansion & improves survival in glioblastoma

Abstract Background: Our previous research demonstrated that radiation therapy (RT) for glioblastoma (GBM) induces aberrant myelopoiesis, increasing production of myeloid derived suppressor cells (MDSCs) and exacerbating T-cell suppression. However, the precise biological mechanisms underlying this phenomenon remain unclear. This study aims to elucidate the role of the pro-inflammatory cytokine interleukin-1beta (IL-1β) in RT-induced myelopoiesis and its correlation with poor prognosis in GBM patients. Methods: We conducted an extensive analysis of circulatory immune cells and pro-inflammatory cytokines in GBM patients treated with chemoradiotherapy. Using an orthotopic mouse model of GBM, we investigated the impact of IL-1β on myelopoiesis and survival. Functional assays were employed to examine MDSC expansion. Multi-color flow cytometry was used for immune profiling. Results: We found that RT elevated the plasma IL-1β concentration in both GBM patients and GBM-bearing mice, which also corresponded with an increase of MDSC in blood. In the murine GBM model, RT appeared to promote hematopoietic stem (HSPC) differentiation towards myelopoiesis. This led to increased MDSC precursor cells in the bone marrow, elevated circulating MDSCs in blood, and more infiltration of MDSCs in the tumor microenvironment (TME). Similar effects were observed in GBM-bearing mice following the administration of exogenous IL-1β. In contrast, inhibition of IL-1β using anti-IL-1β antibody during RT led to reduced myelopoiesis. When anti-IL-1β antibody was combined with functional inhibition of MDSCs using phosphodiesterase-5 inhibitor-tadalafil during RT, we observed decreased MDSC infiltration and increased CD8+ T cell infiltration in the TME. The combination approach also extended the survival of GBM-bearing mice after RT longer than either drug alone. Conclusions: Irradiation of GBM appears to induce IL-1β to promote aberrant myelopoiesis and MDSC expansion. A multi-pronged approach to inhibit MDSC production using IL-1β inhibitor and MDSC function using tadalafil during RT may be a promising approach to overcome the immune-suppressive TME of GBM. Citation Format: Subhajit Ghosh, Jiayi Huang, David DeNardo, Dennis Hallahan, Jerry Jaboin, Dinesh Thotala. Targeting IL-1β mitigates radiation induced MDSC expansion & improves survival in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4989.

Severe inflammation in C57/BL6 mice leads to prolonged cognitive impairment by initiating the IL-1β/TRPM2 pathway

BackgroundSepsis could lead to chronic cognitive impairment by unclear molecular mechanisms. Transient receptor potential melastatin-2 (TRPM2) is essential against immunity-related activities and inflammation. Our study attempted to decipher the relationship between cognitive impairment caused by severe inflammation and TRPM2 expression levels. MethodsSevere inflammation was induced by intraperitoneally injecting C57/BL6 mice with a high dosage (5 mg kg−1) of Lipopolysaccharide (LPS). Fear conditioning and a Morris water maze test were performed to examine the cognitive abilities of the mice. Moreover, the signaling and expression of pro-inflammatory cytokines and TRPM2 were measured using Western blotting and Reverse transcription-polymerase chain reaction (RT-PCR). Flow cytometry and immunofluorescence staining helped to determine the astrocyte apoptosis rate. ResultsSevere inflammation can lead to long-term cognitive impairment in C57/BL6 mice. The interleukin-1 beta (IL-1β) levels intra-hippocampus were significantly elevated until P14 post-LPS introduction. At both P7 and P14, there is an up-regulation of TRPM2 expression within hippocampus. Administration of recombinant IL-1β to astrocytes results in a significant up-regulation of TRPM2 expression. IL-1β or TRPM2 level knockdown helped counter the cognitive impairment caused by significant inflammation. ConclusionsA continuous increase in IL-1β levels within the hippocampus can lead to cognitive impairment by enhancing TRPM2 levels caused by severe inflammation.

Lung infection by Pseudomonas aeruginosa induces neuroinflammation and blood–brain barrier dysfunction in mice

BackgroundSevere lung infection can lead to brain dysfunction and neurobehavioral disorders. The mechanisms that regulate the lung-brain axis of inflammatory response to respiratory infection are incompletely understood. This study examined the effects of lung infection causing systemic and neuroinflammation as a potential mechanism contributing to blood–brain barrier (BBB) leakage and behavioral impairment.MethodsLung infection in mice was induced by instilling Pseudomonas aeruginosa (PA) intratracheally. We determined bacterial colonization in tissue, microvascular leakage, expression of cytokines and leukocyte infiltration into the brain.ResultsLung infection caused alveolar-capillary barrier injury as indicated by leakage of plasma proteins across pulmonary microvessels and histopathological characteristics of pulmonary edema (alveolar wall thickening, microvessel congestion, and neutrophil infiltration). PA also caused significant BBB dysfunction characterized by leakage of different sized molecules across cerebral microvessels and a decreased expression of cell–cell junctions (VE-cadherin, claudin-5) in the brain. BBB leakage peaked at 24 h and lasted for 7 days post-inoculation. Additionally, mice with lung infection displayed hyperlocomotion and anxiety-like behaviors. To test whether cerebral dysfunction was caused by PA directly or indirectly, we measured bacterial load in multiple organs. While PA loads were detected in the lungs up to 7 days post-inoculation, bacteria were not detected in the brain as evidenced by negative cerebral spinal fluid (CSF) cultures and lack of distribution in different brain regions or isolated cerebral microvessels. However, mice with PA lung infection demonstrated increased mRNA expression in the brain of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α), chemokines (CXCL-1, CXCL-2) and adhesion molecules (VCAM-1 and ICAM-1) along with CD11b + CD45+ cell recruitment, corresponding to their increased blood levels of white cells (polymorphonuclear cells) and cytokines. To confirm the direct effect of cytokines on endothelial permeability, we measured cell–cell adhesive barrier resistance and junction morphology in mouse brain microvascular endothelial cell monolayers, where administration of IL-1β induced a significant reduction of barrier function coupled with tight junction (TJ) and adherens junction (AJ) diffusion and disorganization. Combined treatment with IL-1β and TNFα augmented the barrier injury.ConclusionsLung bacterial infection is associated with BBB disruption and behavioral changes, which are mediated by systemic cytokine release.

Interleukin-1 contributes to clonal expansion and progression of bone marrow fibrosis in JAK2V617F-induced myeloproliferative neoplasm

Chronic inflammation is frequently associated with myeloproliferative neoplasms (MPN), but the role of inflammation in the pathogenesis of MPN remains unclear. Expression of the proinflammatory cytokine interleukin-1 (IL-1) is elevated in patients with MPN as well as in Jak2V617F knock-in mice. Here, we show that genetic deletion of IL-1 receptor 1 (IL-1R1) normalizes peripheral blood counts, reduces splenomegaly and ameliorates bone marrow fibrosis in homozygous Jak2V617F mouse model of myelofibrosis. Deletion of IL-1R1 also significantly reduces Jak2V617F mutant hematopoietic stem/progenitor cells. Exogenous administration of IL-1β enhances myeloid cell expansion and accelerates the development of bone marrow fibrosis in heterozygous Jak2V617F mice. Furthermore, treatment with anti-IL-1R1 antibodies significantly reduces leukocytosis and splenomegaly, and ameliorates bone marrow fibrosis in homozygous Jak2V617F mice. Collectively, these results suggest that IL-1 signaling plays a pathogenic role in MPN disease progression, and targeting of IL-1R1 could be a useful strategy for the treatment of myelofibrosis.

Pioglitazone attenuates ischaemic stroke aggravation by blocking PPARγ reduction and inhibiting chronic inflammation in diabetic mice

Diabetes can cause vascular remodelling and is associated with worse outcome after ischaemic stroke. Pioglitazone is a commonly used anti-diabetic agent. However, it is not known whether pioglitazone use before ischaemia could reduce brain ischaemic injury. Pioglitazone was administered to 5-week-old db+ or db/db mice. Cerebral vascular remodelling was examined at the age of 9weeks. Expression of peroxisome proliferator-activated receptor-γ (PPARγ), p-PPARγ (S112 and S273), nucleotide-binding domain (NOD)-like receptor protein 3 (Nlrp3), interleukin-1β (IL-1β) and tumour necrosis factor-α (TNF-α) was evaluated in the somatosensory cortex of mice. Neurological outcome was evaluated 24 h after brain ischaemia. Results showed that early pioglitazone treatment provided a long-lasting effect of euglycaemia but enhanced hyperlipidaemia in the db/db mice. Diabetic mice exhibited increased vascular tortuosity, narrower middle cerebral artery (MCA) width and IgG leakage in the brain. These changes were blocked by early pioglitazone treatment. In diabetic animals, PPARγ expression was reduced, and p-PPARγ at S273 but not S112, Nlrp3, IL-1β and TNF-α were increased in the somatosensory cortex. PPARγ decrease and Nlrp3 increase were mainly in the neurons of the diabetic brain, which was reversed by early pioglitazone treatment. Pioglitazone attenuated the aggravated neurological outcome after stroke in diabetic mice. But this protective effect was abolished through restoring cerebral inflammation by intracerebroventricular administration of IL-1β and TNF-α in pioglitazone-treated diabetic mice before MCAO. In summary, early pioglitazone treatment attenuates cerebral vascular remodelling and ischaemic brain injury possibly via blocking chronic neuroinflammation in the db/db mice.

A unique cerebellar pattern of microglia activation in a mouse model of encephalopathy of prematurity.

Preterm infants often show pathologies of the cerebellum, which are associated with impaired motor performance, lower IQ and poor language skills at school ages. Using a mouse model of inflammation‐induced encephalopathy of prematurity driven by systemic administration of pro‐inflammatory IL‐1β, we sought to uncover causes of cerebellar damage. In this model, IL‐1β is administered between postnatal day (P) 1 to day 5, a timing equivalent to the last trimester for brain development in humans. Structural MRI analysis revealed that systemic IL‐1β treatment induced specific reductions in gray and white matter volumes of the mouse cerebellar lobules I and II (5% false discovery rate [FDR]) from P15 onwards. Preceding these MRI‐detectable cerebellar volume changes, we observed damage to oligodendroglia, with reduced proliferation of OLIG2+ cells at P10 and reduced levels of the myelin proteins myelin basic protein (MBP) and myelin‐associated glycoprotein (MAG) at P10 and P15. Increased density of IBA1+ cerebellar microglia were observed both at P5 and P45, with evidence for increased microglial proliferation at P5 and P10. Comparison of the transcriptome of microglia isolated from P5 cerebellums and cerebrums revealed significant enrichment of pro‐inflammatory markers in microglia from both regions, but cerebellar microglia displayed a unique type I interferon signaling dysregulation. Collectively, these data suggest that perinatal inflammation driven by systemic IL‐1β leads to specific cerebellar volume deficits, which likely reflect oligodendrocyte pathology downstream of microglial activation. Further studies are now required to confirm the potential of protective strategies aimed at preventing sustained type I interferon signaling driven by cerebellar microglia as an important therapeutic target.

Neural circuits mediating circulating interleukin-1β-evoked fever in the absence of prostaglandin E2 production

Infectious diseases and inflammatory conditions recruit the immune system to mount an appropriate acute response that includes the production of cytokines. Cytokines evoke neurally-mediated responses to fight pathogens, such as the recruitment of thermoeffectors, thereby increasing body temperature and leading to fever. Studies suggest that the cytokine interleukin-1β (IL-1β) depends upon cyclooxygenase (COX)-mediated prostaglandin E2 production for the induction of neural mechanisms to elicit fever. However, COX inhibitors do not eliminate IL-1β-induced fever, thus suggesting that COX-dependent and COX-independent mechanisms are recruited for increasing body temperature after peripheral administration of IL-1β. In the present study, we aimed to build a foundation for the neural circuit(s) controlling COX-independent, inflammatory fever by determining the involvement of brain areas that are critical for controlling the sympathetic outflow to brown adipose tissue (BAT) and the cutaneous vasculature. In anesthetized rats, pretreatment with indomethacin, a non-selective COX inhibitor, did not prevent BAT thermogenesis or cutaneous vasoconstriction (CVC) induced by intravenous IL-1β (2 µg/kg). BAT and cutaneous vasculature sympathetic premotor neurons in the rostral raphe pallidus area (rRPa) are required for IL-1β-evoked BAT thermogenesis and CVC, with or without pretreatment with indomethacin. Additionally, activation of glutamate receptors in the dorsomedial hypothalamus (DMH) is required for COX-independent, IL-1β-induced BAT thermogenesis. Therefore, our data suggests that COX-independent mechanisms elicit activation of neurons within the DMH and rRPa, which is sufficient to trigger and mount inflammatory fever. These data provide a foundation for elucidating the brain circuits responsible for COX-independent, IL-1β-elicited fevers.

Abstract 12774: Effects of Interleukin-1β on Cardiac Reserve and Exercise Capacity in the Mouse

Introduction: Heart failure (HF) is characterized by dyspnea, fatigue, and exercise intolerance. Clinical evidence points to increased interleukin-1β (IL-1β) activity in patients with HF, with IL-1 blockade improving the exercise capacity in HF patients. In healthy mice, recombinant-mouse IL-1β (rmIL-1β) induces acute systolic dysfunction, peaking 4 hours after administration. However, the direct effects of rmIL-1β on exercise capacity are unknown. Hypothesis: rmIL-1β diminishes the exercise capacity in the mouse. Methods: Adult mice were trained to run on a treadmill and exercise capacity was assessed before, 4, and 96 hours after intraperitoneal rmIL-1β (3 μg/kg) or vehicle (0.9% NaCl) administration (N=7-10/group). In separate groups of mice, left ventricular ejection fraction (LVEF) was assessed at baseline, 4, and 96 hours after stimulation using transthoracic echocardiography. The ultrasound operator was blind to treatments. The cardiac reserve was measured by calculating the difference in LVEF before and after β-adrenergic stimulation using isoproterenol (10 ng/mouse) in IL-1β or vehicle-treated mice (N=5-11/group). Results: Treatment with rmIL-1β significantly reduced exercise capacity measured at 4 and 96 hours (32% reduction at 4 hours and 33% reduction at 96 hours, P<0.01 vs baseline for both time points), whereas no effect was observed in the vehicle-treated group (P<0.05 for IL-1β vs vehicle). LVEF was significantly reduced 4 hours after treatment with rmIL-1β (29% reduction, P<0.01 vs baseline at 4 hours), without any significant changes after vehicle. After 96 hours, LVEF had recovered to pre-treatment values. Cardiac reserve was significantly reduced at 4 and at 96 hours after IL-1β group (7% LVEF change at 4 hours and 2% at 96 hours P<0.05 vs baseline for both time points) and not after vehicle (P<0.05 for IL-1β vs vehicle). Conclusions: Administration of exogenous IL-1β reduces exercise capacity through an impairment in cardiac reserve.

Intrathecal interleukin-1β decreases sigma-1 receptor expression in spinal astrocytes in a murine model of neuropathic pain

The sigma-1 receptor (Sig-1R) plays an important role in spinal pain transmission by increasing phosphorylation of the N-methyl-D-aspartate (NMDA) receptor GluN1 subunit (pGluN1). As a result Sig-1R has been suggested as a novel therapeutic target for prevention of chronic pain. Here we investigated whether interleukin-1β (IL-1β) modulates the expression of the Sig-1R in spinal astrocytes during the early phase of nerve injury, and whether this modulation affects spinal pGluN1 expression and the development of neuropathic pain following chronic constriction injury (CCI) of the sciatic nerve. Repeated intrathecal (i.t.) administration of IL-1β from days 0–3 post-surgery significantly reduced the increased pGluN1 expression at the Ser896 and Ser897 sites in the ipsilateral spinal cord, as well as, the development of mechanical allodynia and thermal hyperalgesia in the ipsilateral hind paw of CCI mice, which were restored by co-administration of IL-1 receptor antagonist with IL-1β. Sciatic nerve injury increased the expression of Sig-1R in astrocytes of the ipsilateral spinal cord, and this increase was suppressed by i.t. administration of IL-1β. Agonistic stimulation of the Sig-1R with PRE084 restored pGluN1 expression and the development of mechanical allodynia that were originally suppressed by IL-1β in CCI mice. Collectively these results demonstrate that IL-1β administration during the induction phase of neuropathic pain produces an analgesic effect on neuropathic pain development by controlling the expression of Sig-1R in spinal astrocytes.

CCL2‒CCR2 Signaling in the Skin Drives Surfactant-Induced Irritant Contact Dermatitis through IL-1β‒Mediated Neutrophil Accumulation

Surfactant-induced cumulative irritant contact dermatitis (ICD) is a common and clinically important skin disorder. CCL2 is known to mediate inflammation after tissue damage in various organs. Thus, we investigated whether and how CCL2 contributes to the development of murine cumulative ICD induced by a common surfactant, SDS. Wild-type mice treated topically with SDS for 6 consecutive days developed skin inflammation that recapitulated the features of human cumulative ICD, including barrier disruption, epidermal thickening, and neutrophil accumulation. CCL2 was upregulated in SDS-treated skin, and local CCL2 blockade attenuated SDS-induced ICD. SDS-induced ICD and neutrophil accumulation were also attenuated in mice deficient in CCR2, the receptor for CCL2. Neutrophil depletion alleviated SDS-induced ICD, suggesting that impaired neutrophil accumulation was responsible for the amelioration of ICD in CCR2-deficient mice. In RNA-sequencing analyses of SDS-treated skin, the expression levels of Il1b in Ccr2-deficient mice were highly downregulated compared with those in wild-type mice. Furthermore, the intradermal administration of IL-1β in the SDS-treated skin of CCR2-deficient mice restored the local accumulation of neutrophils and the development of ICD. Collectively, our results suggest that CCL2‒CCR2 signaling in the skin critically promotes the development of SDS-induced ICD by inducing IL-1β expression for neutrophil accumulation.

IL‐1β‐Induced Thermoregulation and Vagus Nerve Activity is Mediated by Transient Receptor Potential Ankyrin 1

Intraperitoneal administration of interleukin-1β (IL-1β), a cytokine mediator of inflammation and injury, induces afferent vagus nerve signaling and brain-mediated sickness syndrome. However, the mechanism of IL-1β signaling through the vagus nerve is unknown. Here we show that transient receptor potential ankyrin 1 (TRPA1) expression in sensory vagus neurons is required to mediateIL-1β-induced thermoregulation and vagus nerve activation. We monitored body temperature in conscious and unrestrained mice by radiotelemetry using probes implanted into peritoneal cavity. Intraperitoneal administration of IL-1β induced a significant change in body temperature in wild type mice. However, this response was significantly impaired in TRPA1 knock out mice (TRPA1 KO) (wild type vs. TRPA1 KO; 1045 ± 35.29 AUC vs. 577.9 ± 26.13 AUC; t-test with Welch's correction; p<0.0001). To investigate whether selective TRPA1 expression in neurons is required for IL-1β-induced thermoregulation, we generated Syn-Cre/TRPA1fl/fl mice selectively devoid of TRPA1 expression in neurons. Selective ablation of TRPA1-expression in neurons significantly attenuates IL-1β-induced changes in body temperature (wild type vs. Syn-Cre/TRPA1fl/fl; 1082 ± 61.49 AUC vs. 775.8 ± 66.89 AUC; t-test with Welch's correction; p<0.01). We have previously shown IL-1β induces sensory signaling by recording vagus nerve activity. Accordingly, here we collected extra-neural recordings from the cervical vagus nerve and as expected observed administration of IL-1β induced a significant increase in vagus nerve activity (total spikes 5 minutes pre- and post-administration: 85.6 ± 0.17 spikes vs. 9998.0 ± 3617.0 spikes; t-test; p<0.01). Moreover, no significant changes in vagus nerve activity occurred in TRPA1 KO mice (pre vs post-administration: 867.3 ± 395.7 spikes vs. 1069.0 ± 455.8 spikes, t-test, N.S.), and in Syn-Cre/TRPA1fl/fl mice (pre vs post-administration: 2179.0 ± 558.8 spikes vs. 1996.0 ± 460.8 spikes; t-test; N.S.). Whole-cell patch-clamp recordings and calcium imaging revealed TRPA1 is required to mediate IL-1β-dependent activation of vagus sensory neurons. Together, these studies indicate IL-1β-induced thermoregulation and vagus nerve activation is mediated by TRPA1.

Maternal administration of probiotics promotes gut development in mouse offsprings.

Necrotizing enterocolitis is the most common gastrointestinal disorder in premature neonates. This disease is characterized by massive epithelial necrosis, gut barrier dysfunction and improper mucosal defense development. Studies have shown that probiotic administration can decrease NEC incidence and mortality. The proposed mechanisms of probiotics for the prevention of NEC are: promotion of intestinal development; improved barrier function through decreased apoptosis and improved mucin production; decreased expression of proinflammatory cytokines IL6, IL8, and TNFα, and modulation of microbiota dysbiosis in preterm infants. However, reported sepsis in the immunocompromised preterm host has deterred routine prophylactic administration of probiotics in the neonatal intensive care unit. We hypothesize that maternal administration of probiotics to pregnant mouse dams can recapitulate the beneficial effects observed in neonates fed with probiotics directly. We exposed pregnant mice to the probiotics and monitored the changes in the developing intestines of the offspring. Pregnant mice were fed daily with the probiotics Lactobacillus acidophilus and Bifidobacterium infantis (LB) from embryonic day15 to 2-week-old postnatally. Intraperitoneal administration of IL-1β in the pups was used to model proinflammatory insults. Sera were collected at 2 weeks of age and evaluated for inflammatory cytokines by enzyme-linked-immunosorbent-assay and gut permeability by Fluorescein isothiocyanate-dextran tracer assay. Ileal tissues were collected for the evaluation of apoptosis and proliferation of the intestinal epithelium; as well as mucin and tight junction integrity at mucosal surface by immunofluorescent staining. We find that maternal LB exposure facilitated intestinal epithelial cell differentiation, prevented loss of mucin and preserved the intestinal integrity and barrier function and decreased serum levels of IL-1β, TNF-α and IL-6 in the preweaned offsprings. in LB exposed pups. We demonstrate that maternal probiotic supplementation promotes gut maturation in developing offspring. This is potentially a safe alternative therapy to induce intestinal maturation and prevent prematurity-associated neonatal disorders.

Участие оксида азота в механизмах влияния провоспалительного цитокина ИЛ-1β на гиперкапнический вентиляционный ответ

The aim of the current study was to compare the respiratory effects of IL-1β before and after pre-treatment with L-NAME, a nonspecific NO-synthases inhibitor. The experiments were performed on tracheotomised anaesthetised rats. The hypercapnic ventilatory response was measured by means of the rebreathing method using a hyperoxic-hypercapnic gas mixture (60 % O2, 7 % CO2) before and after the cerebroventricular administration of human recombinant IL-1β in the amount of 500 ng dissolved in 10 μl of saline. In order to determine the role of the NO-pathway in the ventilatory effects of IL-1β, L-NAME, a non-specific inhibitor of NO-synthase, was used. As a result, the slope of the ventilatory response to carbon dioxide decreased almost twofold at 40 min. after the cerebroventricular administration of IL-1β. In contrast, the basal level of lung ventilation increased after the elevation of IL-1β in CSF. L-NAME pre-treatment reduced these respiratory effects of IL-1β. The data indicate that the inhibitor of NO-synthase significantly reduces the effect of the pro-inflammatory cytokine IL-1β. The authors conclude that the ability of IL-1β to enhance basal ventilation and to reduce the ventilatory hypercapnic response may be mediated by NO-dependent mechanisms.

Analysis of the Effect of IL-1β on Blood-Brain Barrier Permeability in M6 Glioma Mouse Model Using Intravital Microscopy.

We studied the effect of IL-1β on the permeability of brain capillaries in healthy mice. Intravital microscopy demonstrated that parenteral administration of IL-1β was followed by an increase in vascular permeability ensuring passage of free Alexa488 fluorescent label through the capillary walls, but not sufficient for penetration of liposomes. In addition, experiments on mice with intracranial M6 glioma showed penetration of liposomes through the walls of tumor capillaries after parenteral administration of IL-1β in a concentration of 2 μg/ml. Thus, the use of proinflammatory cytokine IL-1β in the therapy of brain tumors can significantly increase the therapeutic efficacy of drug delivery systems, in particular, for drugs poorly crossing the blood-brain barrier.

Host conditioning with IL-1β improves the antitumor function of adoptively transferred T cells

Host conditioning has emerged as an important component of effective adoptive cell transfer-based immunotherapy for cancer. High levels of IL-1β are induced by host conditioning, but its impact on the antitumor function of T cells remains unclear. We found that the administration of IL-1β increased the population size and functionality of adoptively transferred T cells within the tumor. Most importantly, IL-1β enhanced the ability of tumor-specific T cells to trigger the regression of large, established B16 melanoma tumors in mice. Mechanistically, we showed that the increase in T cell numbers was associated with superior tissue homing and survival abilities and was largely mediated by IL-1β-stimulated host cells. In addition, IL-1β enhanced T cell functionality indirectly via its actions on radio-resistant host cells in an IL-2- and IL-15-dependent manner. Our findings not only underscore the potential of provoking inflammation to enhance antitumor immunity but also uncover novel host regulations of T cell responses.

PI3 kinase alpha and delta promote hematopoietic stem cell activation.

Many cytokines and chemokines that are important for hematopoiesis activate the PI3K signaling pathway. Because this pathway is frequently mutated and activated in cancer, PI3K inhibitors have been developed for the treatment of several malignancies, and are now being tested in the clinic in combination with chemotherapy. However, the role of PI3K in adult hematopoietic stem cells (HSCs), particularly during hematopoietic stress, is still unclear. We previously showed that the individual PI3K catalytic isoforms P110α or P110β have dispensable roles in HSC function, suggesting redundancy between PI3K isoforms in HSCs. We now demonstrate that simultaneous deletion of P110α and P110δ in double knockout (DKO) HSCs uncovers their redundant requirement in HSC cycling after 5-fluorouracil (5-FU) chemotherapy administration. In contrast, DKO HSCs are still able to exit quiescence in response to other stress stimuli, such as LPS. We found that DKO HSCs and progenitors have impaired sensing of inflammatory signals ex vivo, and that levels of IL1-β and MIG are higher in the bone marrow after LPS than after 5-FU administration. Furthermore, exogenous in vivo administration of IL1-β can induce cell cycle entry of DKO HSCs. Our findings have important clinical implications for the use of PI3K inhibitors in combination with chemotherapy.

Spinal Interleukin-1β Inhibits Astrocyte Cytochrome P450c17 Expression Which Controls the Development of Mechanical Allodynia in a Mouse Model of Neuropathic Pain

We have recently demonstrated that sciatic nerve injury increases the expression of spinal cytochrome P450c17, a key neurosteroidogenic enzyme, which plays a critical role in the development of peripheral neuropathic pain. However, the modulatory mechanisms responsible for the expression of spinal P450c17 have yet to be examined. Here we investigated the possible involvement of interleukin-1β (IL-1β) in altering P450c17 expression during the induction phase of neuropathic pain. Neuropathic pain was produced by chronic constriction injury (CCI) of the right sciatic nerve in mice and mechanical allodynia was evaluated in the hind paws using a von-Frey filament (0.16 g). Western blotting and immunohistochemistry were performed to assess the expression of spinal IL-1β, interleukin-1 receptor type 1 (IL-1R1), P450c17, and GFAP. Spinal IL-1β was significantly increased on day 1 post-surgery and its receptor, IL-1R1 was expressed in GFAP-positive astrocytes. Intrathecal administration of the recombinant interleukin-1 receptor antagonist (IL-1ra, 20 ng) on days 0 and 1 post-surgery enhanced GFAP expression on day 1 post-surgery and induced an early increase in P450c17 expression in astrocytes, but not in neurons. Administration of IL-1β (10 ng) on days 0 and 1 post-surgery blocked the enhancement of both spinal P450c17 and GFAP expression induced by IL-1ra (20 ng) administration. Intrathecal administration of IL-1ra (20 ng) on days 0 to 3 post-surgery also facilitated the CCI-induced development of mechanical allodynia, and this early developed pain was dose-dependently attenuated by the administration of the P450c17 inhibitor, ketoconazole (1, 3, or 10 nmol) or the astrocyte metabolic inhibitor, fluorocitrate (0.01, 0.03, or 0.1 nmol). These results demonstrate that early increases in spinal IL-1β temporally inhibit astrocyte P450c17 expression and astrocyte activation ultimately controlling the development of mechanical allodynia induced by peripheral nerve injury. These findings imply that spinal IL-1β plays an important role as an early, but transient, control mechanism in the development of peripheral neuropathic pain via the inhibition of astrocyte P450c17 expression and astrocyte activation.

Memory consolidation impairment induced by Interleukin-1β is associated with changes in hippocampal structural plasticity

Pro-inflammatory cytokines, particularly Interleukin-1β (IL-1β), can affect cognitive processes such as learning and memory. The aim of this study was to establish whether the effect of IL-1β on contextual fear memory is associated with changes in hippocampal structural plasticity. We also studied the effect of α-melanocyte-stimulating hormone (α-MSH), a potent anti-inflammatory and neuro-protective peptide. Different groups of animals were implanted bilaterally in dorsal hippocampus (DH). After recovery they were conditioned for contextual fear memory and received the different treatments (vehicle, IL-1β, α-MSH or IL-1β + α-MSH). Memory was assessed 24 hs after conditioning and immediately after rats were perfused for dendritic spine analysis. Our results show that local hippocampal administration of IL-1β just after memory encoding induced impairment in contextual memory and a reduction in the total density of CA1 hippocampal dendritic spines, particularly the mature ones. α-MSH administration reversed the IL-1β induced changes. The results suggest that neuro-inflammation induced by IL-1β interferes with experience-dependent structural plasticity in DH whereas α-MSH has a beneficial modulatory role in preventing this effect.