Arginase activity in alternatively activated macrophages protects PI3Kp110δ deficient mice from dextran sodium sulfate induced intestinal inflammation

FAM76B regulates PI3K/Akt/NF-κB-mediated M1 macrophage polarization by influencing the stability of PIK3CD mRNA

Macrophage polarization is closely related to inflammation development, yet how macrophages are polarized remains unclear. In our study, the number of M1 macrophages was markedly increased in Fam76b knockout U937 cells vs. wild-type U937 cells, and FAM76B expression was decreased in M1 macrophages induced from different sources of macrophages. Moreover, Fam76b knockout enhanced the mRNA and protein levels of M1 macrophage-associated marker genes. These results suggest that FAM76B inhibits M1 macrophage polarization. We then further explored the mechanism by which FAM76B regulates macrophage polarization. We found that FAM76B can regulate PI3K/Akt/NF-κB pathway-mediated M1 macrophage polarization by stabilizing PIK3CD mRNA. Finally, FAM76B was proven to protect against inflammatory bowel disease (IBD) by inhibiting M1 macrophage polarization through the PI3K/Akt/NF-κB pathway in vivo. In summary, FAM76B regulates M1 macrophage polarization through the PI3K/Akt/NF-κB pathway in vitro and in vivo, which may inform the development of future therapeutic strategies for IBD and other inflammatory diseases.

Cystatin from the helminth Ascaris lumbricoides upregulates mevalonate and cholesterol biosynthesis pathways and immunomodulatory genes in human monocyte-derived dendritic cells

Background

Ascaris lumbricoides cystatin (Al-CPI) prevents the development of allergic airway inflammation and dextran-induced colitis in mice models. It has been suggested that helminth-derived cystatins inhibit cathepsins in dendritic cells (DC), but their immunomodulatory mechanisms are unclear. We aimed to analyze the transcriptional profile of human monocyte-derived DC (moDC) upon stimulation with Al-CPI to elucidate target genes and pathways of parasite immunomodulation.

Methods

moDC were generated from peripheral blood monocytes from six healthy human donors of Denmark, stimulated with 1 µM of Al-CPI, and cultured for 5 hours at 37°C. RNA was sequenced using TrueSeq RNA libraries and the NextSeq 550 v2.5 (75 cycles) sequencing kit (Illumina, Inc). After QC, reads were aligned to the human GRCh38 genome using Spliced Transcripts Alignment to a Reference (STAR) software. Differential expression was calculated by DESEq2 and expressed in fold changes (FC). Cell surface markers and cytokine production by moDC were evaluated by flow cytometry.

Results

Compared to unstimulated cells, Al-CPI stimulated moDC showed differential expression of 444 transcripts (|FC| ≥1.3). The top significant differences were in Kruppel-like factor 10 (KLF10, FC 3.3, PBH = 3 x 10-136), palladin (FC 2, PBH = 3 x 10-41), and the low-density lipoprotein receptor (LDLR, FC 2.6, PBH = 5 x 10-41). Upregulated genes were enriched in regulation of cholesterol biosynthesis by sterol regulatory element-binding proteins (SREBP) signaling pathways and immune pathways. Several genes in the cholesterol biosynthetic pathway showed significantly increased expression upon Al-CPI stimulation, even in the presence of lipopolysaccharide (LPS). Regarding the pathway of negative regulation of immune response, we found a significant decrease in the cell surface expression of CD86, HLA-DR, and PD-L1 upon stimulation with 1 µM Al-CPI.

Conclusion

Al-CPI modifies the transcriptome of moDC, increasing several transcripts encoding enzymes involved in cholesterol biosynthesis and SREBP signaling. Moreover, Al-CPI target several transcripts in the TNF-alpha signaling pathway influencing cytokine release by moDC. In addition, mRNA levels of genes encoding KLF10 and other members of the TGF beta and the IL-10 families were also modified by Al-CPI stimulation. The regulation of the mevalonate pathway and cholesterol biosynthesis suggests new mechanisms involved in DC responses to helminth immunomodulatory molecules.

Nmes1 is a novel regulator of mucosal response influencing intestinal healing potential

The initiation of tissue remodeling following damage is a critical step in preventing the development of immune-mediated diseases. Several factors contribute to mucosal healing, leading to innovative therapeutic approaches for managing intestinal disorders. However, uncovering alternative targets and gaining mechanistic insights are imperative to enhance therapy efficacy and broaden its applicability across different intestinal diseases. Here we demonstrate that Nmes1, encoding for Normal Mucosa of Esophagus-Specific gene 1, also known as Aa467197, is a novel regulator of mucosal healing. Nmes1 influences the macrophage response to the tissue remodeling cytokine IL-4 in vitro. In addition, using two murine models of intestinal damage, each characterized by a type 2-dominated environment with contrasting functions, the ablation of Nmes1 results in decreased intestinal regeneration during the recovery phase of colitis, while enhancing parasitic egg clearance and reducing fibrosis during the advanced stages of Schistosoma mansoni infection. These outcomes are associated with alterations in CX3CR1+ macrophages, cells known for their wound-healing potential in the inflamed colon, hence promising candidates for cell therapies. All in all, our data indicate Nmes1 as a novel contributor to mucosal healing, setting the basis for further investigation into its potential as a new target for the treatment of colon-associated inflammation.

Elafibranor modulates ileal macrophage polarization to restore intestinal integrity in NASH: Potential crosstalk between ileal IL-10/STAT3 and hepatic TLR4/NF-κB axes

Experimental and clinical evidence implicate disrupted gut barrier integrity in provoking innate immune responses, specifically macrophages, towards the progression of non-alcoholic steatohepatitis (NASH). Peroxisome proliferator-activated receptors (PPARs), a subset of the nuclear receptor superfamily, act to fine-tune several metabolic and inflammatory processes implicated in NASH. As such, the current study was carried out to decipher the potential role of dual PPAR α/δ activation using elafibranor (ELA) on ileal macrophage polarization (MP) and its likely impact on the liver in a NASH setting. To achieve this aim, an in vitro NASH model using fat-laden HepG2 cells was first used to validate the impact of ELA on hepatic fat accumulation. Afterwards, ELA was used in a combined model of dietary NASH and chronic colitis analogous to the clinical presentation of NASH parallel with intestinal barrier dysfunction. ELA mitigated fat accumulation in vitro as evidenced by Oil Red-O staining and curbed triglyceride levels. Additionally, ELA restored the expression of tight junctional proteins, claudin-1 and occludin, along with decreasing intestinal permeability and inflammation skewing ileal macrophages towards the M2 phenotype, as indicated by boosted arginase-1 (Arg1) and curtailed inducible nitric oxide synthase (iNOS) expression levels. These changes were aligned with a modulation in hepatic toll-like receptor-4 (TLR4)/nuclear factor kappa B (NF-κB) along with ileal interleukin-10 (IL-10)/signal transducer and activator of transcription-3 (STAT3) axes. Overall, the present findings suggest that the dual PPAR α/δ agonist, ELA, may drive MP in the ileum towards the M2 phenotype improving intestinal integrity towards alleviating NASH.

Macrophage immunotherapy: overcoming impediments to realize promise

As an essential component of immunity, macrophages have key roles in mammalian host defense, tissue homeostasis, and repair, as well as in disease pathogenesis and pathophysiology. A source of fascination and extensive research, in this Opinion we challenge the utility of the M1-M2 paradigm, and discuss the importance of accurate characterization of human macrophages. We comment on the application of single cell analytics to define macrophage subpopulations and how this could advance therapeutic options. We argue that human macrophage cell therapy can be used to alleviate many diseases, and offer a viewpoint on the knowledge gaps that must be filled to render such a therapeutic approach a reality and, ideally, a common future practice in precision medicine.

Roflumilast ameliorates cognitive deficits in a mouse model of amyloidogenesis and tauopathy: Involvement of nitric oxide status, Aβ extrusion transporter ABCB1, and reversal by PKA inhibitor H89

The biological cascade of second messenger-cyclic adenosine monophosphate (cAMP) -as a molecular mechanism implicated in memory and learning regulation has captured the attention of neuroscientists worldwide. cAMP triggers its foremost effector, protein kinase A (PKA), resulting in the activation of innumerable downstream targets. Roflumilast (ROF), a phosphodiesterase 4 inhibitor, has demonstrated a greater efficiency in enhancing cAMP signaling in various neurological disorders. This study was conducted to identify various downstream targets of PKA as mechanistic tools through which ROF could hinder the progressive cognitive impairment following central streptozotocin (STZ) administration in mice. Animals were injected with STZ (3 mg/kg/i.c.v) once. Five hours later, mice received ROF (0.4 mg/kg) with or without the PKA inhibitor, H89, for 21 days. ROF highly preserved the structure of hippocampal neurons. It improved the ability of mice to develop short-term memories and retrieve spatial memories in Y-maze and Morris water maze tests, respectively. ROF enhanced the gene expression of ABCB1 transporters and pregnane X receptors (PXR), and hampered Aβ accumulation in hippocampus. Simultaneously, it interfered with the processes of tau phosphorylation and nitration. This effect was associated with an upsurge in hippocampal arginase activity as well as a decline in glycogen synthase kinase-3β activity, nitric oxide synthase (NOS) activity, and inducible NOS expression. Contrariwise, ROF's beneficial effects were utterly abolished by co-administration of H89. In conclusion, boosting PKA, by ROF, modulated PXR/ABCB1 expression and arginase/NOS activities to restrict the main post-translational modifications of tau, Aβ deposition and, accordingly, cognitive deterioration of sporadic Alzheimer's disease.

Interleukin-4 Programmed Macrophages Suppress Colitis and Do Not Enhance Infectious-Colitis, Inflammation-Associated Colon Cancer or Airway Hypersensitivity

The murine interleukin-4 treated macrophage (MIL4) exerts anti-inflammatory and pro-healing effects and has been shown to reduce the severity of chemical-induced colitis. Positing M(IL4) transfer as an anti-inflammatory therapy, the possibility of side-effects must be considered. Consequently, bone marrow-derived M(IL4)s were administered via intraperitoneal injection to mice concomitant with Citrobacter rodentium infection (infections colitis), azoxymethane/dextran sodium sulphate (AOM/DSS) treatment [a model of colorectal cancer (CRC)], or ovalbumin sensitization (airway inflammation). The impact of M(IL4) treatment on C. rodentium infectivity, colon histopathology, tumor number and size and tissue-specific inflammation was examined in these models. The anti-colitic effect of the M(IL4)s were confirmed in the di-nitrobenzene sulphonic acid model of colitis and the lumen-to-blood movement of 4kDa FITC-dextran and bacterial translocation to the spleen and liver was also improved by M(IL4) treatment. Analysis of the other models of disease, that represent comorbidities that can occur in human inflammatory bowel disease (IBD), revealed that M(IL4) treatment did not exaggerate the severity of any of the conditions. Rather, there was reduction in the size (but not number) of polyps in the colon of AOM/DSS-mice and reduced infectivity and inflammation in C. rodentium-infected mice in M(IL4)-treated mice. Thus, while any new therapy can have unforeseen side effects, our data confirm and extend the anti-colitic capacity of murine M(IL4)s and indicate that systemic delivery of one million M(IL4)s did not exaggerate disease in models of colonic or airways inflammation or colonic tumorigenesis.

PI3Kαδ Inhibitor Combined With Radiation Enhances the Antitumor Immune Effect of Anti-PD1 in a Syngeneic Murine Triple-Negative Breast Cancer Model

PURPOSE

The poor response of breast cancer to immune checkpoint blockade might result from low immunogenicity and the immune-suppressive tumor microenvironment. We hypothesized that in situ tumor vaccination via radiation therapy (RT) and suppression of immune tolerance via phosphoinositide 3-kinase δ (PI3Kδ) inhibition would enhance the efficacy of immune checkpoint blockade.

METHODS AND MATERIALS

4T1 murine breast cancer cells were grown in both immune-competent and -deficient BALB/c mice, and tumors were irradiated with 24 Gy in 3 fractions. A PD-1 blockade and a PI3Kαδ inhibitor were then administered every other day for 2 weeks. Fluorescence-activated cell sorting and immunohistochemistry served to monitor subsequent changes in immune cell repertoire.

RESULTS

The triple combination of RT, PD-1 blockade, and PI3Kαδ inhibitor significantly delayed tumor growth. The immune-deficient syngeneic 4T1 murine tumor model failed to show this tumor growth delay. Use of RT and PI3Kαδ inhibitor increased the proportions of CD8⁺ T cells; PI3Kαδ inhibitor led to a decrease in regulatory T cells and polymorphonuclear myeloid-derived suppressor cells. The triple combination resulted in a remarkable increase in cytotoxic CD8⁺ T cells, suggesting a prominent immune-modulatory effect. The abscopal effect was most prominent in the triple-combination therapy group, and it correlated with splenic CD8⁺ T cell accumulation.

CONCLUSIONS

These findings collectively indicate that combining RT, PI3Kαδ inhibitor, and PD-1 blockade could be a viable approach, helping to overcome the therapeutic resistance of immunologically cold tumors, such as breast cancer, with an immunosuppressive tumor microenvironment.

Non-Invasive Differentiation of M1 and M2 Activation in Macrophages Using Hyperpolarized 13C MRS of Pyruvate and DHA at 1.47 Tesla

Macrophage activation, first generalized to the M1/M2 dichotomy, is a complex and central process of the innate immune response. Simply, M1 describes the classical proinflammatory activation, leading to tissue damage, and M2 the alternative activation promoting tissue repair. Given the central role of macrophages in multiple diseases, the ability to noninvasively differentiate between M1 and M2 activation states would be highly valuable for monitoring disease progression and therapeutic responses. Since M1/M2 activation patterns are associated with differential metabolic reprogramming, we hypothesized that hyperpolarized ¹³C magnetic resonance spectroscopy (HP ¹³C MRS), an innovative metabolic imaging approach, could distinguish between macrophage activation states noninvasively. The metabolic conversions of HP [1-¹³C]pyruvate to HP [1-¹³C]lactate, and HP [1-¹³C]dehydroascorbic acid to HP [1-¹³C]ascorbic acid were monitored in live M1 and M2 activated J774a.1 macrophages noninvasively by HP ¹³C MRS on a 1.47 Tesla NMR system. Our results show that both metabolic conversions were significantly increased in M1 macrophages compared to M2 and nonactivated cells. Biochemical assays and high resolution ¹H MRS were also performed to investigate the underlying changes in enzymatic activities and metabolite levels linked to M1/M2 activation. Altogether, our results demonstrate the potential of HP ¹³C MRS for monitoring macrophage activation states noninvasively.

At the Forefront of the Mucosal Barrier: The Role of Macrophages in the Intestine

Macrophages are part of the innate immunity and are key players for the maintenance of intestinal homeostasis. They belong to the group of mononuclear phagocytes, which exert bactericidal functions and help to clear apoptotic cells. Moreover, they play essential roles for the maintenance of epithelial integrity and tissue remodeling during wound healing processes and might be implicated in intestinal tumor development. Macrophages are antigen-presenting cells and secrete immune-modulatory factors, like chemokines and cytokines, which are necessary to activate other intestinal immune cells and therefore to shape immune responses in the gut. However, overwhelming activation or increased secretion of pro-inflammatory cytokines might also contribute to the pathogenesis of inflammatory bowel disease. Presently, intestinal macrophages are in the center of intense studies, which might help to develop new therapeutic strategies to counteract the development or treat already existing inflammatory diseases in the gut. In this review, we focus on the origin of intestinal macrophages and, based on current knowledge, discuss their role in the gut during homeostasis and inflammation, as well as during intestinal wound healing and tumor development.

Human interleukin-4-treated regulatory macrophages promote epithelial wound healing and reduce colitis in a mouse model

Murine alternatively activated macrophages can exert anti-inflammatory effects. We sought to determine if IL-4-treated human macrophages [i.e., hM(IL4)] would promote epithelial wound repair and can serve as a cell transfer treatment for inflammatory bowel disease (IBD). Blood monocytes from healthy volunteers and patients with active and inactive IBD were converted to hM(IL4)s. IL-4 treatment of blood-derived macrophages from healthy volunteers and patients with inactive IBD resulted in a characteristic CD206⁺CCL18⁺CD14^low/- phenotype (RNA-seq revealed IL-4 affected expression of 996 genes). Conditioned media from freshly generated or cryopreserved hM(IL4)s promoted epithelial wound healing in part by TGF, and reduced cytokine-driven loss of epithelial barrier function in vitro. Systemic delivery of hM(IL4) to dinitrobenzene sulphonic acid (DNBS)-treated Rag1^-/- mice significantly reduced disease. These findings from in vitro and in vivo analyses provide proof-of-concept support for the development of autologous M(IL4) transfer as a cellular immunotherapy for IBD.

Myeloid-Derived Suppressor Cell-Derived Arginase-1 Oppositely Modulates IL-17A and IL-17F Through the ESR/STAT3 Pathway During Colitis in Mice

Myeloid-derived suppressor cells (MDSC) play a crucial role in regulating the intestinal immune response during colitis. We previously revealed an essential role of MDSC in promoting TH17 cell polarization, which was found to be arginase-1 (Arg-1)-dependent; however, the underlying mechanism remains obscure. Here we report that percentage of MDSC decreased in Arg^myeKO mice during DSS-induced colitis. IL-17A levels reduced but IL-17F levels increased significantly in the colorectum of Arg^myeKO mice, leading to severe tissue damage and high risk of mortality rate. Activation of estrogen receptor (ESR) increased pSTAT3 level in MDSC and consequently led to elevated percentage of MDSC and more Arg-1 and inducible nitric oxide synthase expression in MDSC. Increased level of IL-17A and reduced level of IL-17F alleviated colitis in mice consequently. Together, these findings demonstrate a protective role of MDSC-derived Arg-1 during colitis after activates ESR/STAT3 signaling in MDSC. High level of Arg-1 favors accumulation of IL-17A, but reduced IL-17F expression in the colorectum of mice and ultimately leading to relief of colitis, indicating a potential clinical impact of MDSC-derived Arg-1 for controlling inflammatory bowel disease.

Role of miR-155 in pathogenesis of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a non-infectious, non-specific intestinal inflammatory disease, and its incidence is increasing year by year. A better understanding of the pathogenesis of IBD can help to find more suitable treatment methods for this disease. Recently, a large number of studies have shown that miR-155 plays an important role in the pathogenesis of IBD. It can regulate TH17 differentiation through the Jarid2/notch1 signaling pathway and by regulating type 2 macrophage differentiation. It also regulates T-regulatory cells by inhibiting cytotoxic T lymphocyte-associated antigen-4; intestinal myelofibrosis through suppressor of cytokine signaling 1; and DNA double-strand break deposition to affect intestinal inflammation. This article reviews the immune mechanism of action of miR-155 in IBD.

Phosphatidylinositol 3-kinase p110δ drives intestinal fibrosis in SHIP deficiency

Crohn's disease is an immune-mediated disease characterized by inflammation along the gastrointestinal tract. Fibrosis requiring surgery occurs in one-third of people with Crohn's disease but there are no treatments for intestinal fibrosis. Mice deficient in the SH2 domain-containing inositolpolyphosphate 5'-phosphatase (SHIP), a negative regulator of phosphatidylinositol 3-kinase (PI3K) develop spontaneous Crohn's disease-like intestinal inflammation and arginase I (argI)-dependent fibrosis. ArgI is up-regulated in SHIP deficiency by PI3Kp110δ activity. Thus, we hypothesized that SHIP-deficient mice develop fibrosis due to increased PI3Kp110δ activity. In SHIP-deficient mice, genetic ablation or pharmacological inhibition of PI3Kp110δ activity reduced intestinal fibrosis, including muscle thickening, accumulation of vimentin⁺ mesenchymal cells, and collagen deposition. PI3Kp110δ deficiency or inhibition also reduced ileal inflammation in SHIP-deficient mice suggesting that PI3Kp110δ may contribute to inflammation. Targeting PI3Kp110δ activity may be an effective strategy to reduce intestinal fibrosis, and may be particularly effective in the subset of people with Crohn's disease, who have low SHIP activity.

Intravenous immunoglobulin (IVIg) or IVIg-treated macrophages reduce DSS-induced colitis by inducing macrophage IL-10 production

Intravenous immunoglobulin (IVIg) is used to treat immune-mediated diseases but its mechanism of action is poorly understood. We have reported that co-treatment with IVIg and lipopolysaccharide activates macrophages to produce large amounts of anti-inflammatory IL-10 in vitro. Thus, we asked whether IVIg-treated macrophages or IVIg could reduce intestinal inflammation in mice during dextran sulfate sodium (DSS)-induced colitis by inducing macrophage IL-10 production in vivo. Adoptive transfer of IVIg-treated macrophages reduces intestinal inflammation in mice and collagen accumulation post-DSS. IVIg treatment also reduces DSS-induced intestinal inflammation and its activity is dependent on the Fc portion of the antibody. Ex vivo, IVIg induces IL-10 production and reduces IL-12/23p40 and IL-1β production in colon explant cultures. Co-staining tissues for mRNA, we demonstrate that macrophages are the source of IL-10 in IVIg-treated mice; and using IL-10-GFP reporter mice, we demonstrate that IVIg induces IL-10 production by intestinal macrophages. Finally, IVIg-mediated protection is lost in mice deficient in macrophage IL-10 production (LysMcre^+/- IL-10^fl/fl mice). Together, our data demonstrate a novel, in vivo mechanism of action for IVIg. IVIg-treated macrophages or IVIg could be used to treat people with intestinal inflammation and may be particularly useful for people with inflammatory bowel disease, who are refractory to therapy.

Macrophages treated with antigen from the tapeworm Hymenolepis diminuta condition CD25+ T cells to suppress colitis

Macrophages play central roles in immunity as early effectors and modulating adaptive immune reponses; we implicated macrophages in the anticolitic effect of infection with the tapeworm Hymenolepis diminuta. Here, gene arrays revealed that H. diminuta antigen (HdAg) evoked a program in murine macrophages distinct from that elicited by IL-4. Further, HdAg suppressed LPS-evoked release of TNF-α and IL-1β from macrophages via autocrine IL-10 signaling. In assessing the ability of macrophages treated in vitro with an extract of H. diminuta [M^(HdAg)] to affect disease, intravenous, but not peritoneal, injection of M^(HdAg) protected wild-type but not RAG1^-/- mice from dinitrobenzene sulphonic acid (DNBS)-induced colitis. Administration of splenic CD4⁺ T cells from in vitro cocultures with M^(HdAg), but not those cocultured with M^(IL-4) cells, inhibited DNBS-induced colitis; fractionation of the T-cell population indicated that the CD4⁺CD25⁺ T cells from cocultures with M^(HdAg) drove the suppression of DNBS-induced colitis. Use of IL-4^-/- or IL-10^-/- CD4⁺ T cells revealed that neither cytokine alone from the donor cells was essential for the anticolitic effect. These data illustrate that HdAg evokes a unique regulatory program in macrophages, identifies HdAg-evoked IL-10 suppression of macrophage activation, and reveals the ability of HdAg-treated macrophages to educate ( i.e., condition) and mobilize CD4⁺CD25⁺ T cells, which could be deployed to treat colonic inflammation.-Reyes, J. L., Lopes, F., Leung, G., Jayme, T. S., Matisz, C. E., Shute, A., Burkhard, R., Carneiro, M., Workentine, M. L., Wang, A., Petri, B., Beck, P. L., Geuking, M. B., McKay, D. M., Macrophages treated with antigen from the tapeworm Hymenolepis diminuta condition CD25⁺ T cells to suppress colitis.

Depletion and Reconstitution of Macrophages in Mice

Macrophages are innate immune cells, which have important roles in the inflammatory response to infections or tissue injury, and have an equally important role in the resolution of inflammation. Macrophages play a key part in directing the innate immune response and subsequent adaptive immune response. They can acquire a variety of distinct but also overlapping activation states, depending on the local microenvironment, in order to perform these functions. Stimuli, such as IFNγ and LPS, can promote an inflammatory activation state, which is associated with the production of reactive oxygen species, and pro-inflammatory cytokines and chemokines. Immune complexes and LPS can promote an anti-inflammatory activation state to prevent damage to the host, which is associated with the production of high levels of the anti-inflammatory cytokine IL-10 and low levels of pro-inflammatory cytokines. Wound-healing macrophages can be activated by IL-4 or IL-13 and have roles in tissue remodeling and the resolution of inflammation. Macrophages are present in nearly every tissue of the body and are important for maintaining homeostasis, but their dysfunction can also lead to diseases, such as inflammatory bowel disease. To study the role macrophages play in a complex in vivo environment, depletion and reconstitution experiments can be utilized. Clodronate liposomes are an effective and versatile way to deplete macrophages in vivo; they can allow selective depletion from tissues of interest and can be used on transgenic mice. However, clodronate liposomes deplete all types of macrophages as well as dendritic cells, so other strategies are required in parallel to determine whether macrophages or macrophages of a particular activation state are required. Reconstitution of macrophages by adoptive transfer can be performed, with or without prior depletion, to further suggest that the observed effect is macrophage dependent. Macrophages activated ex vivo or macrophages from transgenic mice can be adoptively transferred during disease models to determine whether a specific protein or activation state affects disease outcome. Macrophage contribution to health and disease can be effectively studied using depletion with clodronate liposomes and by macrophage reconstitution, as demonstrated in this chapter.

Malt1 blocks IL-1β production by macrophages in vitro and limits dextran sodium sulfate-induced intestinal inflammation in vivo

This study tested the hypothesis that Malt1 deficiency in macrophages contributes to dextran sodium sulfate (DSS)-induced intestinal inflammation in Malt1-deficient mice. In people, combined immunodeficiency caused by a homozygous mutation in the MALT1 gene is associated with increased susceptibility to bacterial infections and chronic inflammation, including severe inflammation along the gastrointestinal tract. The consequences of Malt1 deficiency have largely been attributed to its role in lymphocytes, but Malt1 is also expressed in macrophages, where it is activated downstream of TLR4 and dectin-1. The effect of Malt1 deficiency in murine macrophages and its contribution to DSS-induced colitis have not been investigated. Our objectives were to compare the susceptibility of Malt1^+/+ and Malt1^-/- mice to DSS-induced colitis, to determine the contribution of macrophages to DSS-induced colitis in Malt1^-/- mice, and to assess the effect of innate immune stimuli on Malt1^-/- macrophage inflammatory responses. We found that Malt1 deficiency exacerbates DSS-induced colitis in mice, accompanied by higher levels of IL-1β, and that macrophages and IL-1 signaling contribute to pathology in Malt1^-/- mice. Malt1^-/- macrophages produce more IL-1β in response to either TLR4 or dectin-1 ligation, whereas inhibition of Malt1 proteolytic (paracaspase) activity blocked IL-1β production. TLR4 or dectin-1 stimulation induced Malt1 protein levels but decreased its paracaspase activity. Taken together, these data support the hypothesis that Malt1^-/- macrophages contribute to increased susceptibility of Malt1^-/- mice to DSS-induced colitis, which is dependent on IL-1 signaling. Increased IL-1β production by MALT1-deficient macrophages may also contribute to chronic inflammation in people deficient in MALT1.

Pharmacological inactivation of the PI3K p110δ prevents breast tumour progression by targeting cancer cells and macrophages

Patient selection for PI3K-targeted solid cancer treatment was based on the PIK3CA/PTEN mutational status. However, it is increasingly clear that this is not a good predictor of the response of breast cancer cells to the anti-proliferative effect of PI3K inhibitors, indicating that isoform(s) other than p110α may modulate cancer cells sensitivity to PI3K inhibition. Surprisingly, we found that although no mutations in the p110δ subunit have been detected thus far in breast cancer, the expression of p110δ becomes gradually elevated during human breast cancer progression from grade I to grade III. Moreover, pharmacological inactivation of p110δ in mice abrogated the formation of tumours and the recruitment of macrophages to tumour sites and strongly affected the survival, proliferation and apoptosis of grafted tumour cells. Pharmacological inactivation of p110δ in mice with defective macrophages or in mice with normal macrophages but grafted with p110δ-lacking tumours suppressed only partly tumour growth, indicating a requisite role of p110δ in both macrophages and cancer cells in tumour progression. Adoptive transfer of δD910A/D910A macrophages into mice with defected macrophages suppressed tumour growth, eliminated the recruitment of macrophages to tumour sites and prevented metastasis compared with mice that received WT macrophages further establishing that inactivation of p110δ in macrophage prevents tumour progression. Our work provides the first in vivo evidence for a critical role of p110δ in cancer cells and macrophages during solid tumour growth and may pave the way for the use of p110δ inhibitors in breast cancer treatment.

Critical Role of Alternative M2 Skewing in miR-155 Deletion-Mediated Protection of Colitis

Inflammatory bowel disease (IBD) is associated with dysregulation of both innate and adaptive immune response in the intestine. MicroRNA (miR)-155 is frequently expressed and functions in many immune cell types. Besides its function in adaptive immunity, miR-155 is a key regulator of the innate immune response in macrophages, dendritic cells, and even in epithelia cells. Although the roles of miR-155 within T and B lymphocytes in colitis have been reported, its function in innate immune cells has not been thoroughly examined. In this study, the dextran sulfate sodium (DSS)-induced colitis model was established in wild-type (WT) and miR-155^−/− mice. Our results showed that miR-155 deficiency in macrophages recapitulated the alleviated colitis feature of miR-155^−/− mice and appeared to skew toward the alterative M2 phenotype. Notably, the predominance of M2 in colon can result in dampened intestinal immune cell proliferation and inhibit CD4 T cell polarization toward Th1 and Th17. Moreover, C/EBPβ and SOCS1 were demonstrated as two key functional targets in this process. We also provided evidence for use of miR-155 inhibitor to treat colitis. Collectively, the findings highlight the central role of alternative M2 skewing for miR-155 function in colitis and reveal that macrophages might be a main target for therapeutics.

SHIP negatively regulates type II immune responses in mast cells and macrophages

SHIP is a hematopoietic-specific lipid phosphatase that dephosphorylates PI3K-generated PI(3,4,5)-trisphosphate. SHIP removes this second messenger from the cell membrane blunting PI3K activity in immune cells. Thus, SHIP negatively regulates mast cell activation downstream of multiple receptors. SHIP has been referred to as the "gatekeeper" of mast cell degranulation as loss of SHIP dramatically increases degranulation or permits degranulation in response to normally inert stimuli. SHIP also negatively regulates Mϕ activation, including both pro-inflammatory cytokine production downstream of pattern recognition receptors, and alternative Mϕ activation by the type II cytokines, IL-4, and IL-13. In the SHIP-deficient (SHIP-/- ) mouse, increased mast cell and Mϕ activation leads to spontaneous inflammatory pathology at mucosal sites, which is characterized by high levels of type II inflammatory cytokines. SHIP-/- mast cells and Mϕs have both been implicated in driving inflammation in the SHIP-/- mouse lung. SHIP-/- Mϕs drive Crohn's disease-like intestinal inflammation and fibrosis, which is dependent on heightened responses to innate immune stimuli generating IL-1, and IL-4 inducing abundant arginase I. Both lung and gut pathology translate to human disease as low SHIP levels and activity have been associated with allergy and with Crohn's disease in people. In this review, we summarize seminal literature and recent advances that provide insight into SHIP's role in mast cells and Mϕs, the contribution of these cell types to pathology in the SHIP-/- mouse, and describe how these findings translate to human disease and potential therapies.

PI3K p85α Subunit-deficient Macrophages Protect Mice from Acute Colitis due to the Enhancement of IL-10 Production

We investigated the role of the PI3K p85α subunit in the development of acute colitis with a focus on intestinal macrophages. Experimental acute colitis was induced using 3% dextran sulfate sodium (DSS) in drinking water for 7 days. The severity of DSS-induced acute colitis was significantly attenuated in p85α hetero-deficient (p85α+/−) mice compared with WT mice. The expression of proinflammatory mediators in intestinal macrophages isolated from the inflamed colonic mucosa was significantly suppressed in p85α+/− colitis mice compared with WT colitis mice. Interestingly, we found that bone marrow-derived macrophages (BMDMs) from p85α+/− mice produced a significantly higher amount of IL-10 than BMDMs from WT mice. The adoptive transfer of p85α+/− BMDMs, but not WT BMDMs, significantly improved the severity in WT colitis mice, and this effect was reversed by anti-IL-10 antibody. Furthermore, the expression of IL-10 in the intestinal macrophages of p85α+/− normal colonic mucosa was significantly higher than that in the intestinal macrophages of WT normal colonic mucosa. The present results demonstrate that p85α+/− mice exhibit a reduced susceptibility to DSS-induced acute colitis. Our study suggests that a deficiency of PI3K p85α enhances the production of IL-10 in intestinal macrophages, thereby suppressing the development of DSS-induced acute colitis.

Cooperation between the bacterial-derived short-chain fatty acid butyrate and interleukin-22 detected in human Caco2 colon epithelial/carcinoma cells

By generating biologically active factors luminal microbiota shape the intestinal micro-milieu thereby regulating pathological processes such as inflammation and carcinogenesis. Preclinical data suggest that bacterial-derived butyrate and the signal transducer and activator of transcription (STAT)-3 activating cytokine interleukin (IL)-22 display concordant protective properties at the inflamed colonic epithelium. Herein, biochemical cooperation between the short-chain fatty acid butyrate and IL-22 was investigated by focusing on human Caco2 colon epithelial/carcinoma cells. We report that physiological levels of butyrate enhance IL-22 signaling thereby enforcing expression of the prototypic STAT3-downstrean target genes α1-antichymotrypsin and suppressor of cytokine signaling (SOCS)-3. A dual mode of butyrate action on the IL-22/STAT3 axis was identified. Butyrate acted by upregulating IL-22R1, the decisive chain of the heterodimeric IL-22 receptor, and, independent from that, has the potential to directly amplify STAT3-mediated gene activation as detected by chromatin immunoprecipitation analysis of STAT3 binding to the SOCS3 promoter. Since trichostatin A acted similarly, inhibition of histone deacetylases is likely at the root of these butyrate biological properties. The mutual benefit gained from interactions between the host and commensal intestinal bacteria-derived factors is an expanding field of research beginning to affect clinical practice. Data presented herein propose a supportive and fine-tuning role for butyrate in IL-22 signaling that might be therapeutically exploited by local butyrate administration or by increasing its bacterial production in the context of a fiber-rich diet. © 2016 BioFactors, 43(2):283-292, 2017.

Suppression of colitis by adoptive transfer of helminth antigen-treated dendritic cells requires interleukin-4 receptor-α signaling

Infection with helminth parasites has been explored as a treatment for autoimmune and inflammatory diseases. As helminth antigens have potent immunomodulation properties capable of inducing regulatory programs in a variety of cell types, transferring cells treated with helminth antigens represents a novel extension to helminth therapy. Previous work determined that transfer of bone marrow-derived dendritic cells (DC) pulsed with a crude extract of the tapeworm Hymenolepis diminuta (HD) can suppress colitis in recipient mice. The present study explored the mechanism of disease suppression and the importance of interleukin (IL)-4 signaling. Transfer of HD-DCs suppressed dinitrobenzene sulfonic acid (DNBS)-induced colitis through activation of recipient IL-4 receptor-α. The transferred HD-DCs required IL-4Rα and the capacity to secrete IL-10 to drive IL-4 and IL-10 production and to suppress colitis in recipient mice. Treatment of DCs with IL-4 evokes an alternatively activated phenotype, but adoptive transfer of these cells did not affect the outcome of colitis. Collectively, these studies demonstrate the complexity between IL-4 and IL-10 in donor cells and recipient, and the requirement for parasite- and host-derived factors in this novel form of cell therapy. Thus IL-4Rα signaling is revealed as a pathway that could be exploited for helminth antigen cell-based therapy.

Context-Specific and Immune Cell-Dependent Antitumor Activities of α1-Antitrypsin

α1-antitrypsin (AAT), a circulating glycoprotein that rises during acute phase responses and healthy pregnancies, exhibits immunomodulatory properties in several T-cell-dependent immune pathologies. However, AAT does not directly interfere with T-cell responses; instead, it facilitates polarization of macrophages and dendritic cells towards M2-like and tolerogenic cells, respectively. AAT also allows NK cell responses against tumor cells, while attenuating DC-dependent induction of autoimmune NK cell activities. Since AAT-treated macrophages bear resemblance to cancer-promoting tumor-associated macrophages (TAMs), it became imperative to examine the possible induction of tumor permissive conditions by AAT. Here, AAT treatment is examined for its effect on tumor development, metastatic spread, and tumor immunology. Systemic AAT treatment of mice inoculated with B16-F10 melanoma cells resulted in significant inhibition of tumor growth and metastatic spread. Using NK cell-resistant RMA cells, we show that AAT interferes with tumor development in a CD8+ T-cell-dependent manner. Unexpectedly, upon analysis of tumor cellular composition, we identified functional tumor-infiltrating CD8+ T-cells alongside M1-like TAMs in AAT-treated mice. Based on the ability of AAT to undergo chemical modifications, we emulated conditions of elevated reactive nitrogen and oxygen species. Indeed, macrophages were stimulated by treatment with nitrosylated AAT, and IFNγ transcripts were significantly elevated in tumors extracted soon after ischemia-reperfusion challenge. These context-specific changes may explain the differential effects of AAT on immune responses towards tumor cells versus benign antigenic targets. These data suggest that systemically elevated levels of AAT may accommodate its physiological function in inflammatory resolution, without compromising tumor-targeting immune responses.

Helminth Regulation of Immunity: A Three-pronged Approach to Treat Colitis

By reputation, the parasite is a pariah, an unwelcome guest. Infection with helminth parasites evokes stereotypic immune responses in humans and mice that are dominated by T helper (Th)-2 responses; thus, a hypothesis arises that infection with helminths would limit immunopathology in concomitant inflammatory disease. Although infection with some species of helminths can cause devastating disease and affect the course of microbial infections, analyses of rodent models of inflammatory disease reveal that infection with helminth parasites, or treatment with helminth extracts, can limit the severity of autoinflammatory disease, including colitis. Intriguing, but fewer, studies show that adoptive transfer of myeloid immune cells treated with helminth products/extracts in vitro can suppress inflammation. Herein, 3 facets of helminth therapy are reviewed and critiqued: treatment with viable ova or larvae, treatment with crude extracts of the worm or purified molecules, and cellular immunotherapy. The beneficial effect of helminth therapy often converges on the mobilization of IL-10 and regulatory/alternatively activated macrophages, while there are reports on transforming growth factor (TGF)-β, regulatory T cells and dendritic cells, and recent data suggest that helminth-evoked changes in the microbiota should be considered when defining anticolitic mechanisms. We speculate that if the data from animal models translate to humans, noting the heterogeneity therein, then the choice between use of viable helminth ova, helminth extracts/molecules or antigen-pulsed immune cells could be matched to disease management in defined cohorts of patients with inflammatory bowel disease.

Butyrate enhances antibacterial effects while suppressing other features of alternative activation in IL-4-induced macrophages

The short-chain fatty acid butyrate is produced by fermentation of dietary fiber by the intestinal microbiota; butyrate is the primary energy source of colonocytes and has immunomodulatory effects. Having shown that macrophages differentiated with IL-4 [M(IL-4)s] can suppress colitis, we hypothesized that butyrate would reinforce an M(IL-4) phenotype. Here, we show that in the presence of butyrate M(IL-4)s display reduced expression of their hallmark markers Arg1 and Ym1 and significantly suppressed LPS-induced nitric oxide, IL-12p40, and IL-10 production. Butyrate treatment likely altered the M(IL-4) phenotype via inhibition of histone deacetylation. Functionally, M(IL-4)s treated with butyrate showed increased phagocytosis and killing of bacteria, compared with M(IL-4) and this was not accompanied by enhanced proinflammatory cytokine production. Culture of regulatory T cells with M(IL-4)s and M(IL-4 + butyrate)s revealed that both macrophage subsets suppressed expression of the regulatory T-cell marker Foxp3. However, Tregs cocultured with M(IL-4 + butyrate) produced less IL-17A than Tregs cocultured with M(IL-4). These data illustrate the importance of butyrate, a microbial-derived metabolite, in the regulation of gut immunity: the demonstration that butyrate promotes phagocytosis in M(IL-4)s that can limit T-cell production of IL-17A reveals novel aspects of bacterial-host interaction in the regulation of intestinal homeostasis.

Sustained Arginase 1 Expression Modulates Pathological Tau Deposits in a Mouse Model of Tauopathy

Tau accumulation remains one of the closest correlates of neuronal loss in Alzheimer's disease. In addition, tau associates with several other neurodegenerative diseases, collectively known as tauopathies, in which clinical phenotypes manifest as cognitive impairment, behavioral disturbances, and motor impairment. Polyamines act as bivalent regulators of cellular function and are involved in numerous biological processes. The regulation of the polyamines system can become dysfunctional during disease states. Arginase 1 (Arg1) and nitric oxide synthases compete for l-arginine to produce either polyamines or nitric oxide, respectively. Herein, we show that overexpression of Arg1 using adeno-associated virus (AAV) in the CNS of rTg4510 tau transgenic mice significantly reduced phospho-tau species and tangle pathology. Sustained Arg1 overexpression decreased several kinases capable of phosphorylating tau, decreased inflammation, and modulated changes in the mammalian target of rapamycin and related proteins, suggesting activation of autophagy. Arg1 overexpression also mitigated hippocampal atrophy in tau transgenic mice. Conversely, conditional deletion of Arg1 in myeloid cells resulted in increased tau accumulation relative to Arg1-sufficient mice after transduction with a recombinant AAV-tau construct. These data suggest that Arg1 and the polyamine pathway may offer novel therapeutic targets for tauopathies.

Altered gp130 signalling ameliorates experimental colitis via myeloid cell-specific STAT3 activation and myeloid-derived suppressor cells

STAT3 regulates the expansion of myeloid-derived suppressor cells (MDSCs) during inflammation, infection and cancer. Hyperactivation of STAT3 in gp130^757F/F mice is associated with protection from experimental colitis. This study determined mechanisms for this protection and compared this to mice with myeloid-specific STAT3-deficiency (LysMcre/STAT3^flox; gp130^757F/F LysMcre/STAT3^flox). Acute and chronic colitis was induced and colons were removed for histological, mRNA and protein analysis. Cell populations from spleen, mesenteric lymph node and colon were analyzed for different myeloid cell populations using flow cytometry. Functions of MDSCs and LPS-stimulated peritoneal macrophages were further characterized by in vitro and in vivo assays. Here we show that the resistance to experimental colitis in gp130^757F/F mice is via myeloid-cell specific STAT3 activation, MDSC expansion and increased production of suppressive and protective cytokines.

Activity of SHIP, Which Prevents Expression of Interleukin 1β, Is Reduced in Patients With Crohn's Disease

BACKGROUND & AIMS

Crohn's disease (CD) is associated with a dysregulated immune response to commensal micro-organisms in the intestine. Mice deficient in inositol polyphosphate 5'-phosphatase D (INPP5D, also known as SHIP) develop intestinal inflammation resembling that of patients with CD. SHIP is a negative regulator of PI3Kp110α activity. We investigated mechanisms of intestinal inflammation in Inpp5d(-/-) mice (SHIP-null mice), and SHIP levels and activity in intestinal tissues of subjects with CD.

METHODS

We collected intestines from SHIP-null mice, as well as Inpp5d(+/+) mice (controls), and measured levels of cytokines of the interleukin 1 (IL1) family (IL1α, IL1β, IL1ra, and IL6) by enzyme-linked immunosorbent assay. Macrophages were isolated from lamina propria cells of mice, IL1β production was measured, and mechanisms of increased IL1β production were investigated. Macrophages were incubated with pan-phosphatidylinositol 3-kinase inhibitors or PI3Kp110α-specific inhibitors. Some mice were given an antagonist of the IL1 receptor; macrophages were depleted from ilea of mice using clodronate-containing liposomes. We obtained ileal biopsies from sites of inflammation and peripheral blood mononuclear cells (PBMCs) from treatment-naïve subjects with CD or without CD (controls), and measured SHIP levels and activity. PBMCs were incubated with lipopolysaccharide and adenosine triphosphate, and levels of IL1β production were measured.

RESULTS

Inflamed intestinal tissues and intestinal macrophages from SHIP-null mice produced higher levels of IL1B and IL18 than intestinal tissues from control mice. We found PI3Kp110α to be required for macrophage transcription of Il1b. Macrophage depletion or injection of an IL1 receptor antagonist reduced ileal inflammation in SHIP-null mice. Inflamed ileal tissues and PBMCs from patients with CD had lower levels of SHIP protein than controls (P < .0001 and P < .0002, respectively). There was an inverse correlation between levels of SHIP activity in PBMCs and induction of IL1β production by lipopolysaccharide and adenosine triphosphate (R(2) = .88).

CONCLUSIONS

Macrophages from SHIP-deficient mice have increased PI3Kp110α-mediated transcription of Il1b, which contributes to spontaneous ileal inflammation. SHIP levels and activity are lower in intestinal tissues and peripheral blood samples from patients with CD than controls. There is an inverse correlation between SHIP activity and induction of IL1β production by lipopolysaccharide and adenosine triphosphate in PBMCs. Strategies to reduce IL1B might be developed to treat patients with CD found to have low SHIP activity.

Protective role of G-CSF in dextran sulfate sodium-induced acute colitis through generating gut-homing macrophages

Granulocyte colony-stimulating factor (G-CSF) is a pleiotropic cytokine best known for its role in promoting the generation and function of neutrophils. G-CSF is also found to be involved in macrophage generation and immune regulation; however, its in vivo role in immune homeostasis is largely unknown. Here, we examined the role of G-CSF in dextran sulfate sodium (DSS)-induced acute colitis using G-CSF receptor-deficient (G-CSFR(-/-)) mice. Mice were administered with 1.5% DSS in drinking water for 5days, and the severity of colitis was measured for the next 5days. GCSFR(-/-) mice were more susceptible to DSS-induced colitis than G-CSFR(+/+) or G-CSFR(-/+) mice. G-CSFR(-/-) mice harbored less F4/80(+) macrophages, but a similar number of neutrophils, in the intestine. In vitro, bone marrow-derived macrophages prepared in the presence of both G-CSF and macrophage colony-stimulating factor (M-CSF) (G-BMDM) expressed higher levels of regulatory macrophage markers such as programmed death ligand 2 (PDL2), CD71 and CD206, but not in arginase I, transforming growth factor (TGF)-β, Ym1 (chitinase-like 3) and FIZZ1 (found in inflammatory zone 1), and lower levels of inducible nitric oxide synthase (iNOS), CD80 and CD86 than bone marrow-derived macrophages prepared in the presence of M-CSF alone (BMDM), in response to interleukin (IL)-4/IL-13 and lipopolysaccharide (LPS)/interferon (IFN)-γ, respectively. Adoptive transfer of G-BMDM, but not BMDM, protected G-CSFR(-/-) mice from DSS-induced colitis, and suppressed expression of tumor necrosis factor (TNF)-α, IL-1β and iNOS in the intestine. These results suggest that G-CSF plays an important role in preventing colitis, likely through populating immune regulatory macrophages in the intestine.

Cryopreserved Interleukin-4-Treated Macrophages Attenuate Murine Colitis in an Integrin β7 - Dependent Manner

The adoptive transfer of alternatively activated macrophages (AAMs) has proven to attenuate inflammation in multiple mouse models of colitis; however, the effect of cryopreservation on AAMs, the ability of previously frozen AAMs to block dinitrobenzene sulfonic acid (DNBS) (Th1) and oxazolone (Th2) colitis and their migration postinjection remains unknown. Here we have found that while cryopreservation reduced mRNA expression of canonical markers of interleukin (IL)-4-treated macrophages [M(IL-4)], this step did not translate to reduced protein or activity, and the cells retained their capacity to drive the suppression of colitis. The anticolitic effect of M(IL-4) adoptive transfer required neither T or B cell nor peritoneal macrophages in the recipient. After injection into the peritoneal cavity, M(IL-4)s migrated to the spleen, mesenteric lymph nodes and colon of DNBS-treated mice. The chemokines CCL2, CCL4 and CX3CL1 were expressed in the colon during the course of DNBS-induced colitis. The expression of integrin β7 on transferred M(IL-4)s was required for their anticolitic effect, whereas the presence of the chemokine receptors CCR2 and CX3CR1 were dispensable in this model. Collectively, the data show that M(IL-4)s can be cryopreserved M(IL-4)s and subsequently used to suppress colitis in an integrin β7-dependent manner, and we suggest that these proof-of-concept studies may lead to new cellular therapies for human inflammatory bowel disease.

Immunoregulatory Role of Myeloid-derived Cells in Inflammatory Bowel Disease

As the frontiers of immunological research expand, new insights into the pathogenesis of long poorly understood diseases, such as inflammatory bowel disease (IBD), are opening up new possible avenues for treatment. Myeloid-derived cells (i.e., monocytes, macrophages, neutrophils, and dendritic cells), long believed to be effector cells driving the initiation of inflammation, have been increasingly shown to have immunoregulatory effects previously underappreciated. Dysfunction in the immunoregulatory roles of these cells may play a part in the pathogenesis of a subset of patients with IBD. The role of myeloid-derived suppressor cells, initially described in cancer, have been shown to play an important role in the balancing of effector and regulatory T cells in inflammation as well, and their role in IBD is also explored. The potential for future cell-based therapies for IBD is enhanced by the advances being made in the understanding of the innate immune system in the intestine.

Oral administration of geraniol ameliorates acute experimental murine colitis by inhibiting pro-inflammatory cytokines and NF-κB signaling

Oral administration of geraniol ameliorates DSS-induced ulcerative colitis in mice.