Type II Interleukin-4 Receptor Activation in Basal Breast Cancer Cells Promotes Tumor Progression via Metabolic and Epigenetic Modulation.

Interleukin-4 (IL4) is a Th2 cytokine that can signal through two different receptors, one of which-the type II receptor-is overexpressed by various cancer cells. Previously, we have shown that type II IL4 receptor signaling increases proliferation and metastasis in mouse models of breast cancer, as well as increasing glucose and glutamine metabolism. Here, we expand on those findings to determine mechanistically how IL4 signaling links glucose metabolism and histone acetylation to drive proliferation in the context of triple-negative breast cancer (TNBC). We used a combination of cellular, biochemical, and genomics approaches to interrogate TNBC cell lines, which represent a cancer type where high expression of the type II IL4 receptor is linked to reduced survival. Our results indicate that type II IL4 receptor activation leads to increased glucose uptake, Akt and ACLY activation, and histone acetylation in TNBC cell lines. Inhibition of glucose uptake through the deletion of Glut1 ablates IL4-induced proliferation. Additionally, pharmacological inhibition of histone acetyltransferase P300 attenuates IL4-mediated gene expression and proliferation in vitro. Our work elucidates a role for type II IL4 receptor signaling in promoting TNBC progression, and highlights type II IL4 signaling, as well as histone acetylation, as possible targets for therapy.

Genetic deficiencies of both IL-4 receptor alpha chain and IL-10 trigger early onset of severe colitis in mice.

Inflammatory bowel diseases are associated with dysregulated inflammatory immune responses in the gastrointestinal tract. We found that deficiencies of both IL-4 receptor alpha chain (IL-4Rα) and IL-10 in BALB/c mice (IL-4Rα × IL-10 KO mice) highly induced spontaneous rectal prolapse and diarrhea. These mice also exhibited severe colitis in their cecum and colon and marked elevation of serum proinflammatory cytokines including TNFα and IFNγ. These pathologies were transmittable with their cecal contents containing Helicobacter spp. Their mesenteric LN cells produced TNFα and IFNγ in response to soluble H. hepaticus antigens and high titers of H. hepaticus-specific serum IgG were also detected. These results suggested the important function of IL-4Rα signaling in controlling the intestinal inflammation and the susceptibility to intestinal microbes including H. hepaticus. Therefore, these IL-4Rα × IL-10 KO mice potentially provide the significant murine model for clarifying the causes and control of spontaneous colitis and intestinal inflammation.

Molecular characterization, expression analysis and cellular location of IL-4/13 receptors in large yellow croaker (Larimichthys crocea).

Interleukin (IL)-4 and IL-13 are closely related class I cytokines that play key roles in the T helper (Th)-2 immune response via heterodimeric receptors. IL-4 signals via both the type I (IL-4Rα/γc) and type II (IL-4Rα/IL-13Rα1) receptor complexes, while IL-13 signals only via the type II receptor complex. IL-13Rα2 is traditionally considered a "decoy" receptor for IL-13. However, the IL-4/13 system and its response to pathogenic infection are still not fully understood in fish. In this study, we identified four IL-4/13 receptor subunit genes in the large yellow croaker (Larimichthys crocea): LcIL-4Rα1, LcIL-4Rα2, LcIL-13Rα1, and LcIL-13Rα2. Sequence analysis showed that these receptors possessed typical characteristic domains, including a signal peptide, two fibronectin type III (FN III)-like domains, and a transmembrane domain, but their cytoplasmic regions were not well conserved. The mRNA and protein of the four IL-4/13 receptors were constitutively expressed in all examined tissues of large yellow croaker. Their mRNAs were also detected in primary head kidney macrophages (PKMs), primary head kidney granulocytes (PKGs), and primary head kidney lymphocytes (PKLs). Immunofluorescence assay further showed that LcIL-4Rα and LcIL-13Rα1 were expressed on the membrane of IgM + B cells. After stimulation by Vibrio alginolyticus and poly (I:C) (a viral dsRNA mimic), the mRNA levels of LcIL-4/13 receptors were significantly upregulated in the head kidney and spleen. Their mRNA levels were also upregulated in head kidney leukocytes in response to poly (I:C) and lipopolysaccharide (LPS) treatment. Moreover, both recombinant LcIL-4/13A and LcIL-4/13B upregulated LcIL-4Rα1 and LcIL-4Rα2 in primary leukocytes, but only recombinant LcIL-4/13A upregulated LcIL-13Rα1 and LcIL-13Rα2. These results indicated that LcIL-4/13 receptors, containing conserved functional domains, may be involved in the IL-4/13-mediated immune response to pathogenic infections in the large yellow croaker.

Association of the IL-4R Q576R Polymorphism with Pediatric Asthma: a meta-analysis.

Background: The relationship between Q576R polymorphism of IL-4 receptor (IL-4R) gene and pediatric asthma risk is still undefined. To this end, this meta-analysis was performed to explore the above controversy. Methods: In this study, we systemically retrieved CNKI, EMBASE, Web of Science, Scopus, Science direct and Pub Med to collect relevant researches, followed by calculation of odds ratio (OR) along with 95% confidence intervals (CIs). STATA 12.0 software was employed in this meta-analysis. Results: We found an association between IL-4R Q576R polymorphism and pediatric asthma risk (GG vs AA: OR = 3.75, 95% CI = 1.89-7.45; AG vs AA: OR = 2.15, 95% CI = 1.36-3.39; the dominant model: OR = 2.25, 95% CI = 1.42-3.57;the recessive model: OR = 3.05, 95% CI = 1.54-6.05). Moreover, there was no obvious publication bias. Conclusion: Our findings suggested that G allele of IL-4R Q576R polymorphism is associated with increased risk of pediatric asthma. Anyhow, delicately-designed, large-scale studies should be conducted to further confirm the current outcomes.

IL4/IL4R signaling promotes the osteolysis in metastatic bone of CRC through regulating the proliferation of osteoclast precursors.

BACKGROUND: Bone metastasis of colorectal cancer (CRC) often indicates a poor prognosis. Osteolysis can be observed in metastatic sites, implying an aberrant activation of osteoclasts. However, how osteoclastogenesis is regulated in metastatic microenvironment caused by colorectal cancer is still unclear. METHODS: In this study, mice bone metastatic model of CRC was established through injection of MC-38 or CT-26 cells. BrdU assays showed primary CD115 ( +) osteoclast precursors (OCPs) proliferated at the first 2 weeks. Transcriptomic profiling was performed to identify differentially expressing genes and pathways in OCPs indirectly co-cultured with CRC cells RESULTS: The expression of IL4Rα was found to be significantly upregulated in OCPs stimulated by tumor conditioned medium (CM). Further investigation indicated that IL-4 signaling regulated proliferation of OPCs through interacting with type I IL4 receptor, and neutrophils were the main source of IL-4 in bone marrow. The proliferation of OCPs can be inhibited in IL4 deficiency mice. In addition, ERK pathway was activated by IL4/IL4R signaling. Ravoxertinib, an ERK antagonists, could significantly prevent bone destruction through inhibiting the proliferation of OCPs. CONCLUSION: Our study indicates the essential role of IL4/IL4R signaling for the proliferation of OCPs in early metastasis of CRC predominantly through activating ERK pathway, which remarkedly impacts the number of osteoclasts in later stage and leads to osteolytic lesions. Moreover, Ravoxertinib could be a new therapeutical target for bone metastasis of CRC.

Analysis of PI3K Pathway Associated Molecules Reveals Dysregulated Innate and Adaptive Functions of B Cells in Early Diffuse Cutaneous Systemic Sclerosis.

B cell activation is an early event in the development of systemic sclerosis (SSc). The classical activation of B cells downstream of the B-cell receptor (BCR) involves the phosphatidylinositol-3 kinase (PI3K) pathway that integrates the effects of multiple co-stimulatory receptors. Our analysis of PI3K pathway associated molecules in peripheral blood B cells of early diffuse cutaneous SSc (dcSSc) patients showed altered mRNA expression of Toll-like receptor (TLR) homolog CD180, TLR4, complement component 3, IL-4 receptor and secreted phosphoprotein 1 (SPP1). Parallel to this, we found elevated basal SPP1 secretion in dcSSc B cells, but, with BCR + IL-4 receptor co-stimulation, we could not induce further secretion. CD180 stimulation alone resulted in NF-κB activation in more B cells than CD180 + BCR co-stimulation both in dcSSc and healthy control (HC), but the co-engagement increased the phosphorylation of NF-κB only in dcSSc B cells. Additionally, in contrast with HC B cells, the lower basal production of IL-10 by dcSSc B cells could not be elevated with CD180 stimulation. Furthermore, activation via CD180 increased the percentage of CD86+ switched memory (CD27+IgD-) B cells in dcSSc compared to HC. Our results suggest that alternative B cell activation and CD180 dysfunction cause imbalance of regulatory mechanisms in dcSSc B cells.

A non-canonical type 2 immune response coordinates tuberculous granuloma formation and epithelialization.

The central pathogen-immune interface in tuberculosis is the granuloma, a complex host immune structure that dictates infection trajectory and physiology. Granuloma macrophages undergo a dramatic transition in which entire epithelial modules are induced and define granuloma architecture. In tuberculosis, relatively little is known about the host signals that trigger this transition. Using the zebrafish-Mycobacterium marinum model, we identify the basis of granuloma macrophage transformation. Single-cell RNA-sequencing analysis of zebrafish granulomas and analysis of Mycobacterium tuberculosis-infected macaques reveal that, even in the presence of robust type 1 immune responses, countervailing type 2 signals associate with macrophage epithelialization. We find that type 2 immune signaling, mediated via stat6, is absolutely required for epithelialization and granuloma formation. In mixed chimeras, stat6 acts cell autonomously within macrophages, where it is required for epithelioid transformation and incorporation into necrotic granulomas. These findings establish the signaling pathway that produces the hallmark structure of mycobacterial infection.

Characterization of DLBCL with a PMBL gene expression signature.

Primary mediastinal large B-cell lymphoma (PMBL) is a type of aggressive B-cell lymphoma that typically affects young adults, characterized by presence of a bulky anterior mediastinal mass. Lymphomas with gene expression features of PMBL have been described in nonmediastinal sites, raising questions about how these tumors should be classified. Here, we investigated whether these nonmediastinal lymphomas are indeed PMBLs or instead represent a distinct group within diffuse large B-cell lymphoma (DLBCL). From a cohort of 325 de novo DLBCL cases, we identified tumors from patients without evidence of anterior mediastinal involvement that expressed a PMBL expression signature (nm-PMBLsig+; n = 16; 5%). A majority of these tumors expressed MAL and CD23, proteins typically observed in bona fide PMBL (bf-PMBL). Evaluation of clinical features of nm-PMBLsig+ cases revealed close associations with DLBCL, and a majority displayed a germinal center B cell-like cell of origin (GCB). In contrast to patients with bf-PMBL, patients with nm-PMBLsig+ presented at an older age and did not show pleural disease, and bone/bone marrow involvement was observed in 3 cases. However, although clinically distinct from bf-PMBL, nm-PMBLsig+ tumors resembled bf-PMBL at the molecular level, with upregulation of immune response, JAK-STAT, and NF-κB signatures. Mutational analysis revealed frequent somatic gene mutations in SOCS1, IL4R, ITPKB, and STAT6, as well as CD83 and BIRC3, with the latter genes significantly more frequently affected than in GCB DLBCL or bf-PMBL. Our data establish nm-PMBLsig+ lymphomas as a group within DLBCL with distinct phenotypic and genetic features. These findings may have implications for gene expression- and mutation-based subtyping of aggressive B-cell lymphomas and related targeted therapies.

Tetracyclines improve experimental lymphatic filariasis pathology by disrupting interleukin-4 receptor-mediated lymphangiogenesis.

Lymphatic filariasis is the major global cause of nonhereditary lymphedema. We demonstrate that the filarial nematode Brugia malayi induced lymphatic remodeling and impaired lymphatic drainage following parasitism of limb lymphatics in a mouse model. Lymphatic insufficiency was associated with elevated circulating lymphangiogenic mediators, including vascular endothelial growth factor C. Lymphatic insufficiency was dependent on type 2 adaptive immunity, the interleukin-4 receptor, and recruitment of C-C chemokine receptor-2-positive monocytes and alternatively activated macrophages with a prolymphangiogenic phenotype. Oral treatments with second-generation tetracyclines improved lymphatic function, while other classes of antibiotic had no significant effect. Second-generation tetracyclines directly targeted lymphatic endothelial cell proliferation and modified type 2 prolymphangiogenic macrophage development. Doxycycline treatment impeded monocyte recruitment, inhibited polarization of alternatively activated macrophages, and suppressed T cell adaptive immune responses following infection. Our results determine a mechanism of action for the antimorbidity effects of doxycycline in filariasis and support clinical evaluation of second-generation tetracyclines as affordable, safe therapeutics for lymphedemas of chronic inflammatory origin.

Possible Roles of Interleukin-4 and -13 and Their Receptors in Gastric and Colon Cancer.

Interleukin (IL)-4 and -13 are structurally and functionally related cytokines sharing common receptor subunits. They regulate immune responses and, moreover, are involved in the pathogenesis of a variety of human neoplasms. Three different receptors have been described for IL-4, but only IL-4 receptor type II (IL-4Rα/IL-13Rα1) is expressed in solid tumors. While IL-13 can also bind to three different receptors, IL-13 receptor type I (IL-4Rα/IL-13Rα1/IL-13Rα2) and type II (IL-4Rα/IL-13Rα1) are expressed in solid tumors. After receptor binding, IL-4 and IL-13 can mediate tumor cell proliferation, survival, and metastasis in gastric or colon cancer. This review summarizes the results about the role of IL-4/IL-13 and their receptors in gastric and colon cancer.

Polymorphisms of IL-4 and IL-4R are associated to some demographic characteristics of differentiated thyroid cancer patients but are not determinants of risk in the Brazilian population.

BACKGROUND: IL-4 is known to present abnormal expression in thyroid tumors and SNPs in the IL-4 and its receptor IL-4R genes are associated to risk and mortality of various types of cancer. METHODS: In order to evaluate their role in differentiated thyroid cancer (DTC), we investigated genetic frequencies of two IL-4 promoter SNPs (rs2070874 C>T, rs2243250 C>T) and four non-synonymous SNPs of the IL-4R gene (rs1805010 A>G, rs1805012 C>T, rs1805013 C>T, rs1801275 A>G) in 300 DTC patients matched to 300 controls. All patients were managed according to current guidelines and followed-up for a period of 12-252 months (69.20 ± 52.70 months). RESULTS: Although none of the six investigated SNPs showed association with risk of DTC, rs1805010 was associated with age of diagnosis and the SNPs rs1805012 and rs1801275 were associated to gender. Further, in-silico analysis showed that all these three SNPs were able to cause decreased stability of the protein. We were not able to demonstrate any other association to clinical features of aggressiveness or to patients' prognosis. CONCLUSIONS: These findings indicate that although genetic variants in IL-4 and IL-4R do not influence the risk or outcome of DTC patients, their influence on the behavior of thyroid tumors deserves further investigation.

IL-17 and immunologically induced senescence regulate response to injury in osteoarthritis.

Senescent cells (SnCs) are implicated in the pathogenesis of age-related diseases including osteoarthritis (OA), in part via expression of a senescence-associated secretory phenotype (SASP) that includes immunologically relevant factors and cytokines. In a model of posttraumatic OA (PTOA), anterior cruciate ligament transection (ACLT) induced a type 17 immune response in the articular compartment and draining inguinal lymph nodes (LNs) that paralleled expression of the senescence marker p16INK4a (Cdkn2a) and p21 (Cdkn1a). Innate lymphoid cells, γδ+ T cells, and CD4+ T cells contributed to IL-17 expression. Intra-articular injection of IL-17-neutralizing antibody reduced joint degeneration and decreased expression of the senescence marker Cdkn1a. Local and systemic senolysis was required to attenuate tissue damage in aged animals and was associated with decreased IL-17 and increased IL-4 expression in the articular joint and draining LNs. In vitro, we found that Th17 cells induced senescence in fibroblasts and that SnCs skewed naive T cells toward Th17 or Th1, depending on the presence of TGF-ß. The SASP profile of the inflammation-induced SnCs included altered Wnt signaling, tissue remodeling, and cell-cycle pathways not previously implicated in senescence. These findings provide molecular targets and mechanisms for senescence induction and therapeutic strategies to support tissue healing in an aged environment.

CircIL4R facilitates the tumorigenesis and inhibits ferroptosis in hepatocellular carcinoma by regulating the miR-541-3p/GPX4 axis.

Ferroptosis is a specific iron-dependent cell death form that can induce the production of lipid peroxide, but the roles of circular RNAs (circRNAs) in ferroptosis are completely unaware. Circ-interleukin-4 receptor (circIL4R) was reported to express highly in hepatocellular carcinoma (HCC). This study focused on the function of circIL4R dysregulation in tumor progression and ferroptosis of HCC, as well as its molecular mechanism. The quantitative real-time polymerase chain reaction was implemented for measuring RNA expression. Cell proliferation and survival were evaluated using 3-(4,5-dimethylthiazol-2-y1)-2,5-diphenyl tetrazolium bromide. Apoptotic cells were detected via flow cytometry. The quantification of protein expression was executed through western blotting analysis. The target binding was assessed via the dual-luciferase reporter, RNA immunoprecipitation, and RNA pull-down assays. The experiment in vivo was performed using a xenograft model. CircIL4R was abnormally overexpressed in HCC tissues and cells. CircIL4R knockdown impeded oncogenesis and expedited ferroptosis of HCC cells. CircIL4R could directly sponge microRNA-541-3p (miR-541-3p) and miR-541-3p inhibition mitigated the effects of circIL4R knockdown on HCC cells. CircIL4R acted as a miR-541-3p sponge to regulate its target glutathione peroxidase 4 (GPX4). GPX4 upregulation relieved the miR-541-3p-induced tumor inhibition and ferroptosis aggravation. CircIL4R played an oncogenic role in HCC via the miR-541-3p/GPX4 axis in vivo. Our data suggested that circIL4R served for a tumor promoter and ferroptosis inhibitor in HCC by the miR-541-3p/GPX4 network.

Association analysis of non-synonymous polymorphisms of interleukin-4 receptor-α and interleukin-13 genes in canine atopic dermatitis.

Interleukin-4 (IL4) and interleukin-13 (IL13) are involved in the initial response of T helper 2 lymphocytes through the activation of the IL4 receptor alpha (IL4RA), which is a common receptor chain for these cytokines. In humans, several single-nucleotide polymorphisms (SNPs) identified in the IL4R and in interleukin coding genes were associated with atopic disorders. However, the association between canine IL4R polymorphisms and atopic disorders has not been investigated yet. This study aimed to determine the associations between four non-synonymous SNPs and canine atopic dermatitis (CAD) in shiba inu and miniature dachshund populations. Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis were used to genotype four polymorphisms of canine IL4R and IL13 in 34 shiba inu and 19 miniature dachshund patients with CAD, as well as 29 shiba inu and 39 miniature dachshund patients without the condition. Results from miniature dachshunds revealed a potential association between the presence of minor A allele rs24378020 and CAD (odds ratio, 0.10; 95% confidence interval, 0.01-0.85; Poriginal=0.0062). This CAD resistance allele led to an amino acid substitution (Arg688Cys) that could impair IL4 and IL13 signaling. In shiba inu patients, rs24378020 was fixed by homozygosity of the major G allele. No association was found between the remaining three evaluated SNPs and CAD. Nevertheless, the study suggests that the IL4R Cys688 variant reduces the risk of CAD in miniature dachshunds.

Signaling through the interleukin-4 and interleukin-13 receptor complexes regulates cholangiocyte TMEM16A expression and biliary secretion.

TMEM16A is a Ca2+-activated Cl- channel in the apical membrane of biliary epithelial cells, known as cholangiocytes, which contributes importantly to ductular bile formation. Whereas cholangiocyte TMEM16A activity is regulated by extracellular ATP-binding membrane purinergic receptors, channel expression is regulated by interleukin-4 (IL-4) through an unknown mechanism. Therefore, the aim of the present study was to identify the signaling pathways involved in TMEM16A expression and cholangiocyte secretion. Studies were performed in polarized normal rat cholangiocyte monolayers, human Mz-Cha-1 biliary cells, and cholangiocytes isolated from murine liver tissue. The results demonstrate that all the biliary models expressed the IL-4Rα/IL-13Rα1 receptor complex. Incubation of cholangiocytes with either IL-13 or IL-4 increased the expression of TMEM16A protein, which was associated with an increase in the magnitude of Ca2+-activated Cl- currents in response to ATP in single cells and the short-circuit current response in polarized monolayers. The IL-4- and IL-13-mediated increase in TMEM16A expression was also associated with an increase in STAT6 phosphorylation. Specific inhibition of JAK-3 inhibited the increase in TMEM16A expression and the IL-4-mediated increase in ATP-stimulated currents, whereas inhibition of STAT6 inhibited both IL-4- and IL-13-mediated increases in TMEM16A expression and ATP-stimulated secretion. These studies demonstrate that the cytokines IL-13 and IL-4 regulate the expression and function of biliary TMEM16A channels through a signaling pathway involving STAT6. Identification of this regulatory pathway provides new insight into biliary secretion and suggests new targets to enhance bile formation in the treatment of cholestatic liver disorders.NEW & NOTEWORTHY The Ca2+-activated Cl- channel transmembrane member 16A (TMEM16A) has emerged as an important regulator of biliary secretion and hence, ductular bile formation. The present studies represent the initial description of the regulation of TMEM16A expression in biliary epithelium. Identification of this regulatory pathway involving the IL-4 and IL-13 receptor complex and JAK-3 and STAT-6 signaling provides new insight into biliary secretion and suggests new therapeutic targets to enhance bile formation in the treatment of cholestatic liver disorders.

Kit activates interleukin-4 receptor and effector signal transducer and activator of transcription 6 independent of its cognate ligand in mouse mast cells.

Signaling by Kit has been extensively studied in hematopoietic cells and is essential for the survival, proliferation and maintenance of hematopoietic stem and progenitor cells. In addition to the activation of intrinsic signaling pathways, Kit has been shown to interact with lineage-restricted type I cytokine receptors and produce cross signals, e.g. erythropoietin receptor, interleukin-7 receptor (IL-7R), IL-3R. Based on the earlier studies, we hypothesize that Kit activate other type I cytokine receptors in a cell-specific manner and execute cell-specific function. To investigate other Kit-activated receptors, we tested Kit and IL-4R cross-receptor activation in murine bone-marrow-derived mast cells, which express both Kit and IL-4R at the surface level. Kit upon activation by Kit ligand (KL), activated IL-4Rα, γC , and signal transducer and activator of transcription 6 independent of its cognate ligand IL-4. Though KL and IL-4 are individually mitogenic, combinations of KL and IL-4 synergistically promoted mast cell proliferation. Furthermore, inhibition of lipid raft formation by methyl-ß-cyclodextrin resulted in loss of synergistic proliferation. Together the data suggest IL-4R as a novel Kit-activated receptor. Such cross-receptor activations are likely to be a universal mechanism of Kit signaling in hematopoiesis.

IL-4 receptor engagement in human neutrophils impairs their migration and extracellular trap formation.

BACKGROUND: Type 2 immunity serves to resist parasitic helminths, venoms, and toxins, but the role and regulation of neutrophils during type 2 immune responses are controversial. Helminth models suggested a contribution of neutrophils to type 2 immunity, whereas neutrophils are associated with increased disease severity during type 2 inflammatory disorders, such as asthma. OBJECTIVE: We sought to evaluate the effect of the prototypic type 2 cytokines IL-4 and IL-13 on human neutrophils. METHODS: Human neutrophils from peripheral blood were assessed without or with IL-4 or IL-13 for (1) expression of IL-4 receptor subunits, (2) neutrophil extracellular trap (NET) formation, (3) migration toward CXCL8 in vitro and in humanized mice, and (4) CXCR1, CXCR2, and CXCR4 expression, as well as (5) in nonallergic versus allergic subjects. RESULTS: Human neutrophils expressed both types of IL-4 receptors, and their stimulation through IL-4 or IL-13 diminished their ability to form NETs and migrate toward CXCL8 in vitro. Likewise, in vivo chemotaxis in NOD-scid-Il2rg-/- mice was reduced in IL-4-stimulated human neutrophils compared with control values. These effects were accompanied by downregulation of the CXCL8-binding chemokine receptors CXCR1 and CXCR2 on human neutrophils on IL-4 or IL-13 stimulation in vitro. Ex vivo analysis of neutrophils from allergic patients or exposure of neutrophils from nonallergic subjects to allergic donor serum in vitro impaired their NET formation and migration toward CXCL8, thereby mirroring IL-4/IL-13-stimulated neutrophils. CONCLUSION: IL-4 receptor signaling in human neutrophils affects several neutrophil effector functions, which bears important implications for immunity in type 2 inflammatory disorders.

Impaired interleukin-4 signalling promotes establishment of Haemonchus contortus in sheep.

Reduced worm burden in St. Croix (STC) sheep during Haemonchus contortus (Hc) infection is predicated on rapid interleukin-4 (IL-4) signalling and T helper type 2 immune (Th2) response. The aim of these studies was to further elucidate differences in Th2 responses by STC and Suffolk (SUF) sheep. Ten days after challenge Hc infection, peripheral blood mononuclear cells (PBMC) were collected and cultured with larval (HcLA) and adult worm (HcWA) antigen. STC PBMC produced nearly twice as much IL-4 as SUF (823.57 pg/mL vs 454.28 pg/mL) at 6 hours of HcLA culture despite no difference in IL-4 gene expression and the IL-4 receptor (IL4Rα) was upregulated in STC PBMC but was undetectable in SUF. Expression of other Th2-type genes were increased in STC PBMC including IL13, IL5 and MRC1. IL-4 supplementation to HcLA culture was insufficient to achieve upregulation of Th2 genes in SUF PBMC. Production of IL-4 did not occur in SUF PBMC until 24 hours after culture with HcLA, and expression of IL4 in the abomasum was similarly delayed until 10 days after challenge infection, which was associated with significantly higher larval burden (530 vs 16). These data demonstrate delayed upregulation of Th2 genes in SUF sheep contributes to susceptibility to Hc.

Shared and independent functions of aPKCλ and Par3 in skin tumorigenesis.

The polarity proteins Par3 and aPKC are key regulators of processes altered in cancer. Par3/aPKC are thought to dynamically interact with Par6 but increasing evidence suggests that aPKC and Par3 also exert complex-independent functions. Whereas aPKCλ serves as tumor promotor, Par3 can either promote or suppress tumorigenesis. Here we asked whether and how Par3 and aPKCλ genetically interact to control two-stage skin carcinogenesis. Epidermal loss of Par3, aPKCλ, or both, strongly reduced tumor multiplicity and increased latency but inhibited invasion to similar extents, indicating that Par3 and aPKCλ function as a complex to promote tumorigenesis. Molecularly, Par3/aPKCλ cooperate to promote Akt, ERK and NF-κB signaling during tumor initiation to sustain growth, whereas aPKCλ dominates in promoting survival. In the inflammatory tumorigenesis phase Par3/aPKCλ cooperate to drive Stat3 activation and hyperproliferation. Unexpectedly, the reduced inflammatory signaling did not alter carcinogen-induced immune cell numbers but reduced IL-4 Receptor-positive stromal macrophage numbers in all mutant mice, suggesting that epidermal aPKCλ and Par3 promote a tumor-permissive environment. Importantly, aPKCλ also serves a distinct, carcinogen-independent role in controlling skin immune cell homeostasis. Collectively, our data demonstrates that Par3 and aPKCλ cooperate to promote skin tumor initiation and progression, likely through sustaining growth, survival, and inflammatory signaling.

GM-CSF and IL-4 are not involved in IVIG-mediated amelioration of ITP in mice: a role for IL-11 cannot be ruled out.

Previously, we have reported that interleukin (IL)-4, granulocyte-macrophage colony-stimulating factor (GM-CSF), and IL-11, but not IL-33, are up-regulated in two strains of mice with immune thrombocytopenia (ITP) that are responsive to intravenous immunoglobulin (IVIg) treatment. Previously, IL-4 was ruled out in the mechanism of IVIg; however, other publications have suggested this cytokine as a major player in the mechanism of IVIg action. Thus, we sought to further investigate a role for IL-4 and, in addition, GM-CSF and IL-11 in the mechanism of action of IVIg using a murine model of ITP. A passive platelet antibody model was used to generate ITP in IL-4 receptor knock-out (IL-4R-/- ), IL-11 receptor knock-out (IL-11Rα-/- ) and GM-CSF knock-out (Csf2-/- ) mice. We also used a neutralizing antibody to IL-11 and recombinant human IL-11 (rhIL-11) in addition to depleting basophils in vivo to study the effect of IVIg to ameliorate ITP. Our results showed that basophils, IL-4 and GM-CSF were unimportant in both ITP induction and its amelioration by IVIg. The role of IL-11 in these processes was less clear. Even though IL-11Rα-/- mice with ITP responded to IVIg similarly to wild-type (WT) mice, treatment of ITP WT mice with rhIL-11 instead of IVIg showed an increase in platelet numbers and WT mice administered anti-IL-11 showed a significant reduction in the ability of IVIg to ameliorate the ITP. Our findings indicate that neither IL-4, basophils or GM-CSF have roles in IVIg amelioration of ITP; however, a role for IL-11 requires further study.