Regulation and function of proinflammatory TH17 cells

Interleukin Gene Variability and Periodontal Bacteria in Patients with Generalized Aggressive Form of Periodontitis

Host genetic predispositions to dysregulated immune response can influence the development of the aggressive form of periodontitis (AgP) through susceptibility to oral dysbiosis and subsequent host-microbe interaction. This case-control study aimed to perform a multilocus analysis of functional variants in selected interleukin (IL) genes in patients with the generalized form of AgP in a homogenous population. Twelve polymorphisms in IL-1 gene cluster, IL-6 and its receptor, IL-10, IL-17A, and IL-18 were determined in 91 AgP patients and 210 controls. Analysis of seven selected periodontal bacteria in subgingival sulci/pockets was performed with a commercial DNA-microarray kit in a subgroup of 76 individuals. The pilot in vitro study included stimulation of peripheral blood monocytes (PBMC) from 20 individuals with periodontal bacteria and measurement of IL-10 levels using the Luminex method. Only the unctional polymorphism IL-10 −1087 A/G (rs1800896) and specific IL-10 haplotypes were associated with the development of the disease (p < 0.05, P_corr > 0.05). Four bacterial species occurred more frequently in AgP than in controls (p < 0.01, P_corr < 0.05). Elevated IL-10 levels were found in AgP patients, carriers of IL-10 −1087GG genotype, and PBMCs stimulated by periodontal bacteria (p < 0.05, P_corr > 0.05). We therefore conclude that a combination of genetic predisposition to the altered expression of IL-10 and the presence of specific periodontal bacteria may contribute to Th1/Th2 balance disruption and AgP development.

The LFA-1 antagonist BIRT377 reverses neuropathic pain in prenatal alcohol-exposed female rats via actions on peripheral and central neuroimmune function in discrete pain-relevant tissue regions

Previous reports show that moderate prenatal alcohol exposure (PAE) poses a risk factor for developing neuropathic pain following adult-onset peripheral nerve injury in male rats. Recently, evidence suggests that immune-related mechanisms underlying neuropathic pain in females are different compared to males despite the fact that both sexes develop neuropathy of similar magnitude and duration following chronic constriction injury (CCI) of the sciatic nerve. Data suggest that the actions of peripheral T cells play a greater role in mediating neuropathy in females. The goal of the current study is to identify specificity of immune cell and cytokine changes between PAE and non-PAE neuropathic females by utilizing a well-characterized rodent model of sciatic nerve damage, in an effort to unmask unique signatures of immune-related factors underlying the risk of neuropathy from PAE. Cytokines typically associated with myeloid cell actions such as interleukin (IL)-1β, tumor necrosis factor (TNF), IL-6, IL-4 and IL-10 as well as the neutrophil chemoattractant CXCL1, are examined. In addition, transcription factors and cytokines associated with various differentiated T cell subtypes are examined (anti-inflammatory FOXP3, proinflammatory IL-17A, IL-21, ROR-γt, interferon (IFN)-γ and T-bet). Lymphocyte function associated antigen 1 (LFA-1) is an adhesion molecule expressed on peripheral immune cells including T cells, and regulates T cell activation and extravasation into inflamed tissue regions. A potential therapeutic approach was explored with the goal of controlling proinflammatory responses in neuroanatomical regions critical for CCI-induced allodynia by blocking LFA-1 actions using BIRT377. The data show profound development of hindpaw allodynia in adult non-PAE control females following standard CCI, but not following minor CCI, while minor CCI generated allodynia in PAE females. The data also show substantial increases in T cell-associated proinflammatory cytokine mRNA and proteins, along with evidence of augmented myeloid/glial activation (mRNA) and induction of myeloid/glial-related proinflammatory cytokines, CCL2, IL-1β and TNF in discrete regions along the pain pathway (damaged sciatic nerve, dorsal root ganglia; DRG, and spinal cord). Interestingly, the characteristic anti-inflammatory IL-10 protein response to nerve damage is blunted in neuropathic PAE females. Moreover, T cell profiles are predominantly proinflammatory in neuropathic Sac and PAE females, augmented levels of Th17-specific proinflammatory cytokines IL-17A and IL-21, as well as the Th1-specific factor, T-bet, are observed. Similarly, the expression of RORγt, a critical transcription factor for Th17 cells, is detected in the spinal cord of neuropathic females. Blocking peripheral LFA-1 actions with intravenous (i.v.) BIRT377 reverses allodynia in Sac and PAE rats, dampens myeloid (IL-1β, TNF, CXCL1)- and T cell-associated proinflammatory factors (IL-17A and RORγt) and spinal glial activation. Moreover, i.v. BIRT377 treatment reverses the blunted IL-10 response to CCI observed only in neuropathic PAE rats and elevates FOXP3 in pain-reversed Sac rats. Unexpectedly, intrathecal BIRT377 treatment is unable to alter allodynia in either Sac or PAE neuropathic females. Together, these data provide evidence that: 1) fully differentiated proinflammatory Th17 cells recruited at the sciatic nerve, DRGs and lumbar spinal cord may interact with the local environment to shape the immune responses underlying neuropathy in female rats, and, 2) PAE primes peripheral and spinal immune responses in adult females. PAE is a risk factor in females for developing peripheral neuropathy after minor nerve injury.

Behind Enemy Lines: Immunomodulatory Armamentarium of the Schistosome Parasite

The deeply rooted, intricate relationship between the Schistosoma parasite and the human host has enabled the parasite to successfully survive within the host and surreptitiously evade the host's immune attacks. The parasite has developed a variety of strategies in its immunomodulatory armamentarium to promote infection without getting harmed or killed in the battlefield of immune responses. These include the production of immunomodulatory molecules, alteration of membranes, and the promotion of granuloma formation. Schistosomiasis thus serves as a paradigm for understanding the Th2 immune responses seen in various helminthiases. This review therefore aims to summarize the immunomodulatory mechanisms of the schistosome parasites to survive inside the host. Understanding these immunomodulatory strategies not only provides information on parasite-host interactions, but also forms the basis in the development of novel drugs and vaccines against the schistosome infection, as well as various types of autoimmune and inflammatory conditions.

Interleukin-17 receptor D constitutes an alternative receptor for interleukin-17A important in psoriasis-like skin inflammation

T helper 17 (T_H17) cells and interleukin-17A (IL-17A) produced by them are critical in autoinflammatory diseases, such as psoriasis. IL-17A has been shown to signal through IL-17 receptor A/IL-17 receptor C (IL-17RA/IL-17RC) complex to drive inflammatory responses. However, in a psoriasis model, we found that Il17rc deficiency did not completely ameliorate the disease, suggesting another receptor. In search for another IL-17A-interacting receptor, we found that IL-17RD directly bound IL-17A but not IL-17F or IL-17A/F heterodimer and formed a heterodimer with IL-17RA. IL-17A-, but not IL-17F- or IL-17A/F-, mediated gene expression was defective in Il17rd-deficient keratinocytes. Il17rd deficiency in nonhemopoietic cells attenuated imiquimod-induced psoriasis-like skin inflammation. Although IL-17RC and IL-17RD differentially activated IL-17A-dependent signaling and gene expression, their compound mutation led to complete deficits in keratinocytes. IL-23 was found induced by IL-17A in keratinocytes, dependent on both IL-17RC and IL-17RD, suggesting feed-forward regulation of IL-23/IL-17 axis in psoriasis. Together, IL-17RD constitutes a second functional receptor for IL-17A and, together with IL-17RC, mediates the proinflammatory gene expression downstream of IL-17A.

PTH induces bone loss via microbial-dependent expansion of intestinal TNF+ T cells and Th17 cells

Bone loss is a frequent but not universal complication of hyperparathyroidism. Using antibiotic-treated or germ-free mice, we show that parathyroid hormone (PTH) only caused bone loss in mice whose microbiota was enriched by the Th17 cell-inducing taxa segmented filamentous bacteria (SFB). SFB⁺ microbiota enabled PTH to expand intestinal TNF⁺ T and Th17 cells and increase their S1P-receptor-1 mediated egress from the intestine and recruitment to the bone marrow (BM) that causes bone loss. CXCR3-mediated TNF⁺ T cell homing to the BM upregulated the Th17 chemoattractant CCL20, which recruited Th17 cells to the BM. This study reveals mechanisms for microbiota-mediated gut-bone crosstalk in mice models of hyperparathyroidism that may help predict its clinical course. Targeting the gut microbiota or T cell migration may represent therapeutic strategies for hyperparathyroidism.

Age-related macular degeneration: A two-level model hypothesis

Age-related diseases, including age-related macular degeneration (AMD), are of growing importance in a world where population ageing has become a dominant global trend. Although a wide variety of risk factors for AMD have been identified, age itself remains by far the most important risk factor, making it an urgent priority to understand the connections between underlying ageing mechanisms and pathophysiology of AMD. Ageing is both multicausal and variable, so that differences between individuals in biological ageing processes are the focus of a growing number of pathophysiological studies seeking to explain how ageing contributes to chronic, age-related conditions. The aim of this review is to integrate the available knowledge on the pathophysiology of AMD within the framework of the biology of ageing. One highly significant feature of biological ageing is systemic inflammation, which arises as a second-level response to a first level of molecular damage involving oxidative stress, mutations etc. Combining these insights, the various co-existing pathophysiological explanations in AMD arrange themselves according to a two-level hypothesis. Accordingly, we describe how AMD can be considered the consequence of age-related random accumulation of molecular damage at the ocular level and the subsequent systemic inflammatory host response thereof. We summarize evidence and provide original data to enlighten where evidence is lacking. Finally, we discuss how this two-level hypothesis provides a foundation for thoughts and future studies in prevention, prognosis, and intervention.

Regulation of Pathogenic T Helper 17 Cell Differentiation by Steroid Receptor Coactivator-3

T helper 17 (Th17) cell development is programmed by the orphan nuclear receptor RORγt, but the underlying mechanism is not well understood. Nuclear receptor-mediated transcriptional activation depends on coactivators. Here, we show that steroid receptor coactivator-3 (SRC-3) critically regulates Th17 cell differentiation. Reduced incidence of experimental autoimmune encephalitis (EAE) associated with decreased Th17 cell generation in vivo was observed in mice with SRC-3 deletion specifically in T cells. In vitro, SRC-3 deficiency did not affect TGF-β/IL-6-induced Th17 cell generation but severely impaired pathogenic Th17 differentiation induced by IL-1/IL-6/IL-23. Microarray analysis revealed that SRC-3 not only regulates IL-17A but also IL-1R1 expression. SRC-3 bound to Il17a and Il1r1 loci in a RORγt-dependent manner and was required for recruitment of the p300 acetyltransferase. Thus, SRC-3 is critical for RORγt-dependent gene expression in Th17 cell-driven autoimmune diseases.

Mechanism of pulmonary immunosuppression: extrapulmonary burn injury suppresses bacterial endotoxin-induced pulmonary neutrophil recruitment and neutrophil extracellular trap (NET) formation

Pulmonary immunosuppression often occurs after burn injury (BI). However, the reasons for BI-induced pulmonary immunosuppression are not clearly understood. Neutrophil recruitment and neutrophil extracellular trap (NET) formation (NETosis) are important components of a robust pulmonary immune response, and we hypothesized that pulmonary inflammation and NETosis are defective after BI. To test this hypothesis, we established a mouse model with intranasal LPS instillation in the presence or absence of BI (15% of body surface burn) and determined the degree of immune cell infiltration, NETosis, and the cytokine levels in the airways and blood on d 2. Presence of LPS recruited monocytes and large numbers of neutrophils to the airways and induced NETosis (citrullinated histone H3, DNA, myeloperoxidase). By contrast, BI significantly reduced LPS-mediated leukocyte recruitment and NETosis. This BI-induced immunosuppression is attributable to the reduction of chemokine (C-C motif) ligand (CCL) 2 (monocyte chemoattractant protein 1) and CCL3 (macrophage inflammatory protein 1α). BI also suppressed LPS-induced increase in IL-17A, IL-17C, and IL-17E/IL-25 levels in the airways. Therefore, BI-mediated reduction in leukocyte recruitment and NETosis in the lungs are attributable to these cytokines. Regulating the levels of some of these key cytokines represents a potential therapeutic option for mitigating BI-mediated pulmonary immunosuppression.-Sakuma, M., Khan, M. A. S., Yasuhara, S., Martyn, J. A., Palaniyar, N. Mechanism of pulmonary immunosuppression: extrapulmonary burn injury suppresses bacterial endotoxin-induced pulmonary neutrophil recruitment and neutrophil extracellular trap (NET) formation.

Involvement of T Cell Immunity in Avian Coccidiosis

Avian coccidiosis is caused by Eimeria, which is an intracellular apicomplexan parasite that invades through the intestinal tract to cause devastating disease. Upon invasion through the intestinal epithelial cells, a strong inflammatory response is induced that results in complete villous destruction, diarrhea, hemorrhage, and in severe cases, death. Since the life cycle of Eimeria parasites is complex and comprises several intra- and extracellular developmental stages, the host immune responses are diverse and complex. Interferon-γ-mediated T helper (Th)1 response was originally considered to be the predominant immune response in avian coccidiosis. However, recent studies on other avian T cell lineages such as Th17 and T regulatory cells have implicated their significant involvement in maintaining gut homeostasis in normal and disease states including coccidiosis. Therefore, there is a need to understand better their role in coccidiosis. This review focuses on research findings concerning the host immune response induced by avian coccidiosis in the context of T cell immunity, including expression of T-cell-related cytokines and surface molecules that determine the phenotype of T lymphocytes.

Immunologic mechanisms in asthma

Asthma is a chronic airway disease, which affects more than 300 million people. The pathogenesis of asthma exhibits marked heterogeneity with many phenotypes defining visible characteristics and endotypes defining molecular mechanisms. With the evolution of novel biological therapies, patients, who do not-respond to conventional asthma therapy require novel biologic medications, such as anti-IgE, anti-IL-5 and anti-IL4/IL13 to control asthma symptoms. It is increasingly important for physicians to understand immunopathology of asthma and to characterize asthma phenotypes. Asthma is associated with immune system activation, airway hyperresponsiveness (AHR), epithelial cell activation, mucus overproduction and airway remodeling. Both innate and adaptive immunity play roles in immunologic mechanisms of asthma. Type 2 asthma with eosinophilia is a common phenotype in asthma. It occurs with and without visible allergy. The type 2 endotype comprises; T helper type 2 (Th2) cells, type 2 innate lymphoid cells (ILC2), IgE-secreting B cells and eosinophils. Eosinophilic nonallergic asthma is ILC2 predominated, which produces IL-5 to recruit eosinophil into the mucosal airway. The second major subgroup of asthma is non-type 2 asthma, which contains heterogeneous group of endoypes and phenotypes, such as exercise-induced asthma, obesity induced asthma, etc. Neutrophilic asthma is not induced by allergens but can be induced by infections, cigarette smoke and pollution. IL-17 which is produced by Th17 cells and type 3 ILCs, can stimulate neutrophilic airway inflammation. Macrophages, dendritic cells and NKT cells are all capable of producing cytokines that are known to contribute in allergic and nonallergic asthma. Bronchial epithelial cell activation and release of cytokines, such as IL-33, IL-25 and TSLP play a major role in asthma. Especially, allergens or environmental exposure to toxic agents, such as pollutants, diesel exhaust, detergents may affect the epithelial barrier leading to asthma development. In this review, we focus on the immunologic mechanism of heterogenous asthma phenotypes.

Resolvin E3 attenuates allergic airway inflammation via the interleukin-23-interleukin-17A pathway

We investigated the effects of resolvin E (RvE) 1, RvE2, and RvE3 on IL-4- and IL-33-stimulated bone marrow-derived dendritic cells (BMDCs) from house dust mite (HDM)-sensitized mice. We also investigated the role of RvE3 in a murine model of HDM-induced airway inflammation. In vitro, BMDCs from HDM-sensitized mice were stimulated with IL-4 and IL-33 and then treated with RvE1, RvE2, RvE3, or vehicle. RvE1, RvE2, and RvE3 suppressed IL-23 release from BMDCs. In vivo, RvE3 administrated to HDM-sensitized and challenged mice in the resolution phase promoted a decline in total numbers of inflammatory cells and eosinophils, reduced levels of IL-23 and IL-17 in lavage fluid, and suppressed IL-23 and IL-17A mRNA expression in lung and peribronchial lymph nodes. RvE3 also reduced resistance in the lungs of HDM-sensitized mice. A NanoBiT β-arrestin recruitment assay using human embryonic kidney 293 cells revealed that pretreatment with RvE3 suppressed the leukotriene B4 (LTB4)-induced β-arrestin 2 binding to LTB4 receptor 1 (BLT1R), indicating that RvE3 antagonistically interacts with BLT1R. Collectively, these findings indicate that RvE3 facilitates the resolution of allergic airway inflammation, partly by regulating BLT1R activity and selective cytokine release by dendritic cells. Our results accordingly identify RvE3 as a potential therapeutic target for the management of asthma.-Sato, M., Aoki-Saito, H., Fukuda, H., Ikeda, H., Koga, Y., Yatomi, M., Tsurumaki, H., Maeno, T., Saito, T., Nakakura, T., Mori, T., Yanagawa, M., Abe, M., Sako, Y., Dobashi, K., Ishizuka, T., Yamada, M., Shuto, S., Hisada, T. Resolvin E3 attenuates allergic airway inflammation via the interleukin-23-interleukin-17A pathway.

Plasma cytokine profile on admission related to aetiology in community-acquired pneumonia

BACKGROUND

Potentially unnecessary antibiotic use for community-acquired pneumonia (CAP) contributes to selection of antibiotic-resistant pathogens. Cytokine expression at the time that treatment is started may assist in identifying patients not requiring antibiotics. We determined plasma cytokine patterns in patients retrospectively categorized as strict viral, pneumococcal or combined viral-bacterial CAP.

OBJECTIVE

To investigate whether cytokine-based prediction models can be used to differentiate strict viral CAP from other aetiologies at admission.

METHODS

From 344 hospitalized CAP patients, 104 patients were categorized as viral CAP (n = 17), pneumococcal CAP (n = 48) and combined bacterial-viral CAP (n = 39). IL-6, IL-10, IL-27, IFN-γ and C-reactive protein (CRP) were determined on admission in plasma. Prediction of strict viral aetiology was explored with two multivariate regression models and ROC curves.

RESULTS

Viral pneumonia was predicted by logistic regression using multiple cytokine levels (IL-6, IL-27 and CRP) with an AUC of 0.911 (95% CI: 0.852-0.971, P < .001). For the same patients the AUC of CRP was 0.813 (95% CI: 0.728-0.898, P < .001).

CONCLUSIONS

This study demonstrated differences in cytokine expression in selected CAP patients between viral and bacterial aetiology. Prospective validation studies are warranted.

LFA-1 antagonist (BIRT377) similarly reverses peripheral neuropathic pain in male and female mice with underlying sex divergent peripheral immune proinflammatory phenotypes

Aim:

The majority of preclinical studies investigating aberrant glial-neuroimmune actions underlying neuropathic pain have focused on male rodent models. Recently, studies have shown peripheral immune cells play a more prominent role than glial cells in mediating pathological pain in females. Here, we compared the onset and duration of allodynia in males and females, and the anti-allodynic action of a potentially novel therapeutic drug (BIRT377) that not only antagonizes the action of lymphocyte function-associated antigen-1 (LFA-1) to reduce cell migration in the periphery, but may also directly alter the cellular inflammatory bias.

Methods:

Male and female mice were subjected to peripheral nerve injury chronic constriction injury (CCI) applying two methods, using either 4–0 or 5–0 chromic gut suture material, to examine potential sex differences in the onset, magnitude and duration of allodynia. Hindpaw sensitivity before and after CCI and application of intravenous BIRT377 was assessed. Peripheral and spinal tissues were analyzed for protein (multiplex electrochemiluminescence technology) and mRNA expression (quantitative real-time PCR). The phenotype of peripheral T cells was determined using flow cytometry.

Results:

Sex differences in proinflammatory CCL2 and IL-1β and the anti-inflammatory IL-10 were observed from a set of cytokines analyzed. A profound proinflammatory T cell (Th17) response in the periphery and spinal cord was also observed in neuropathic females. BIRT377 reversed pain, reduced IL-1β and TNF, and increased IL-10 and transforming growth factor (TGF)-β1, also an anti-inflammatory cytokine, in both sexes. However, female-derived T cell cytokines are transcriptionally regulated by BIRT377, as demonstrated by reducing proinflammatory IL-17A production with concurrent increases in IL-10, TGF-β1 and the anti-inflammatory regulatory T cell-related factor, FOXP3.

Conclusion:

This study supports that divergent peripheral immune and neuroimmune responses during neuropathy exists between males and females. Moreover, the modulatory actions of BIRT377 on T cells during neuropathy are predominantly specific to females. These data highlight the necessity of including both sexes for studying drug efficacy and mechanisms of action in preclinical studies and clinical trials.

Multiwalled Carbon Nanotubes of Varying Size Lead to DNA Methylation Changes That Correspond to Lung Inflammation and Injury in a Mouse Model

Diversity in physicochemical properties of engineered multiwalled carbon nanotubes (MWCNTs) increases the complexity involved in interpreting toxicity studies of these materials. Studies indicate that epigenetic changes could be at least partially involved in MWCNTs-induced pro-inflammatory and fibrotic lung pathology. Therefore, we examined distinct methylation changes in response to MWCNTs of varied sizes to identify potential epigenetic biomarkers of MWCNTs exposure and disease progression. C57BL/6 mice were exposed via oropharyngeal instillation to a single dose (50 μg) to one of three differently sized MWCNTs: "narrow short" (NS), "wide short" (WS), and "narrow long" (NL). Vehicle-treated control mice received dispersion media (DM) only. Whole lung lavage fluid (LLF) and lung tissue were collected 24 h and 7 days postexposure to evaluate pro-inflammatory cytokines, epigenetic, or histological responses at acute and subchronic intervals, respectively. Luminometric methylation assay and pyrosequencing were used to measure global DNA methylation as well as promoter methylation of inflammation and fibrosis-related genes, respectively. Pro-inflammatory cytokines, including IL-1ß, IL-6, and TNF-α, were measured using enzyme-linked immunosorbant assay, while airway thickening and interstitial collagen accumulation were measured in 7-day lung tissue using laser scanning cytometry. Distinct patterns of methylation (i.e., IL-1ß, IL-6, and TNF-α) among the different sized MWCNTs at 24 h postexposure corresponded to some pro-inflammatory cytokine measurements from whole LLF. Fibrosis-related gene, Thy-1, was significantly hypermethylated after exposures to WS and NL MWCNTs, while only NL MWCNTs induced significantly lower global DNA methylation. After 7 days, a hierarchy in airway thickness and interstitial collagen deposition was observed: NS < WS < NL. However, only airway thickness was significantly greater in the WS and NL MWCNTs-exposed groups than the DM-exposed group. These data suggest that methylation changes could be involved in the initial immune response of inflammation and tissue remodeling that precedes lung disease in response to different MWCNTs sizes.

Microbiome Dependent Regulation of Tregs and Th17 Cells in Mucosa

Mammals co-exist with resident microbial ecosystem that is composed of an incredible number and diversity of bacteria, viruses and fungi. Owing to direct contact between resident microbes and mucosal surfaces, both parties are in continuous and complex interactions resulting in important functional consequences. These interactions govern immune homeostasis, host response to infection, vaccination and cancer, as well as predisposition to metabolic, inflammatory and neurological disorders. Here, we discuss recent studies on direct and indirect effects of resident microbiota on regulatory T cells (T_regs) and Th17 cells at the cellular and molecular level. We review mechanisms by which commensal microbes influence mucosa in the context of bioactive molecules derived from resident bacteria, immune senescence, chronic inflammation and cancer. Lastly, we discuss potential therapeutic applications of microbiota alterations and microbial derivatives, for improving resilience of mucosal immunity and combating immunopathology.

IL-17 Receptor Signaling in Osteoblasts/Osteocytes Mediates PTH-Induced Bone Loss and Enhances Osteocytic RANKL Production

Primary hyperparathyroidism (PHPT) is a condition where elevated PTH levels lead to bone loss, in part through increased production of the osteoclastogenic factor IL-17A, by bone marrow (BM) T-helper 17 (Th17) cells, a subset of helper CD4+ T cells. In animals, PHPT is modeled by continuous PTH treatment (cPTH). In mice, an additional critical action of cPTH is the capacity to increase the production of RANKL by osteocytes. However, a definitive link between IL-17A and osteocytic expression of RANKL has not been made. Here we show that cPTH fails to induce cortical and trabecular bone loss and causes less intense bone resorption in conditional knock-out (IL-17RA^ΔOCY ) male and female mice lacking the expression of IL-17A receptor (IL-17RA) in dentin matrix protein 1 (DMP1)-8kb-Cre-expressing cells, which include osteocytes and some osteoblasts. Therefore, direct IL-17RA signaling in osteoblasts/osteocytes is required for cPTH to exert its bone catabolic effects. In addition, in vivo, silencing of IL-17RA signaling in in DMP1-8kb-expressing cells blunts the capacity of cPTH to stimulate osteocytic RANKL production, indicating that cPTH augments osteocytic RANKL expression indirectly, via an IL-17A/IL-17RA-mediated mechanism. Thus, osteocytic production of RANKL and T cell production of IL-17A are both critical for the bone catabolic activity of cPTH. © 2018 American Society for Bone and Mineral Research.

Bcl11b Regulates IL-17 Through the TGF-β/Smad Pathway in HDM-Induced Asthma

PURPOSE

T helper (Th) 17 cells play a critical role in the development of asthma, but the underlying mechanism of how interleukin (IL)-17 is regulated in allergic airway inflammation is poorly understood. In this study, we investigated the impact of Bcl11b on Th17 response in asthma.

METHODS

Blood samples from patients with mild asthma (MA) and severe asthma (SA) were collected. Expression of Bcl11b, IL-4, IL-5, IL-13, IL-17A and transforming growth factor (TGF)-β1 were determined in CD4⁺ T cells and plasma by polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA). Relative mRNA and protein levels of Bcl11b, IL-17A and genes involved in the TGF/Smad signaling pathway were examined by PCR, ELISA and western blot analysis in house dust mite (HDM)-challenged mice. Ectopic expression of Bcl11b in HDM-stimulated primary mouse splenocytes was achieved by nucleofection of Bcl11b expression plasmid.

RESULTS

We found significantly decreased Bcl11b but increased IL-17A and TGF-β1 expression in patients with asthma and a strongly negative correlation between Bcl11b and these 2 cytokines in SA patients. Similar expression patterns of Bcl11b, IL-17A and TGF-β1 were also found in mice with HDM-induced allergic airway inflammation. We demonstrated further that Smad2/3 phosphorylation was increased in HDM-challenged mice and that ectopic expression of Bcl11b in HDM-stimulated primary mouse splenocytes reduced Smad2 phosphorylation and IL-17 expression.

CONCLUSIONS

Our findings demonstrate a potential effect of Bc111b in controlling IL-17-mediated inflammation in asthma and suggest that Bc111b may be a useful therapeutic target for asthma.

T helper 17 cell/regulatory T-cell imbalance in hidradenitis suppurativa/acne inversa: the link to hair follicle dissection, obesity, smoking and autoimmune comorbidities

BACKGROUND

Disintegration of the infundibula of terminal hair follicles (HFs) in intertriginous skin areas exhibits the histological hallmark of hidradenitis suppurativa (HS)/acne inversa, featuring a dissecting terminal hair folliculitis. Elevated serum levels of interleukin (IL)-17 and local increase in the ratio of proinflammatory T helper (Th)17 cells and anti-inflammatory regulatory T cells (Tregs) have been reported. Perifollicular Tregs play a key role in HF stem cell homeostasis and infundibular integrity.

OBJECTIVES

In this review, we evaluate the Th17/Treg ratio in HS, its aggravating conditions and associated comorbidities. Furthermore, we intended to clarify whether drugs with reported beneficial effects in the treatment of HS readjust the deviated Th17/Treg axis.

METHODS

PubMed-listed, peer-reviewed original research articles characterizing Th17/Treg regulation in HS/acne inversa and associated comorbidities were selected for this review.

RESULTS

This review presents HS as a disease that exhibits an increased Th17/Treg ratio. Perifollicular deficiencies in Treg numbers or function may disturb HF stem cell homeostasis, initiating infundibular dissection of terminal HFs and perifollicular inflammation. The Th17/Treg imbalance is aggravated by obesity, smoking and decreased Notch signalling. In addition, HS-associated autoimmune diseases exhibit a disturbed Th17/Treg axis resulting in a Th17-dominant state. All drugs that have beneficial effects in the treatment of HS normalize the Th17/Treg ratio.

CONCLUSIONS

HS immunopathogenesis is closely related to deviations of the Th17/Treg balance, which may negatively affect Treg-controlled HF stem cell homeostasis and infundibular integrity. Pharmacological intervention should not only attenuate Th17/IL-17 signalling, but should also improve Treg function in order to stabilize HF stem cell homeostasis and infundibular integrity.

IL-17 deficiency attenuates acetaminophen-induced hepatotoxicity in mice

Acetaminophen (APAP) overdose results in the production of reactive oxygen species (ROS), hepatocyte necrosis, and cell death, and leads to acute liver failure. Interleukin-17 (IL-17), a pro-inflammatory cytokine, plays a key role in the recruitment of neutrophils into sites of inflammation and subsequent damage after liver ischemia-reperfusion injury. In this study, we employed IL-17 knockout (KO) mice to investigate the role of IL-17 in APAP-induced hepatotoxicity. IL-17 wide type (WT) and IL-17 KO mice received an intraperitoneal injection of APAP (300 mg/kg). After 16 h of treatment, the hepatic injury, inflammatory mediators, immune cell infiltration, and western blotting were examined and analyzed. The serum alanine transferase (ALT) enzyme levels and hepatic myeloperoxidase (MPO) activity were significantly elevated 16 h after APAP treatment in the WT mice. IL-17 deficiency significantly attenuates APAP-induced liver injury, MPO activity, pro-inflammatory cytokines (tumor necrosis factor-α, IL-6 and interferon-γ) levels and inflammatory cell (neutrophils, macrophage) infiltration in the liver. Moreover, phosphorylated extracellular signal-regulated kinase (ERK) was significantly decreased at 16 h after APAP treatment in the IL-17 KO mice compared with the IL-17 WT mice. Our data suggests that IL-17 plays a pivotal role in APAP-induced hepatotoxicity through modulation of inflammatory response, and perhaps in part through the ERK signaling pathway. Blockade of IL-17 could be a potential therapeutic target for APAP-induced hepatotoxicity.

Immunoporosis: Immunology of Osteoporosis-Role of T Cells

The role of immune system in various bone pathologies, such as osteoporosis, osteoarthritis, and rheumatoid arthritis is now well established. This had led to the emergence of a modern field of systems biology called as osteoimmunology, an integrated research between fields of immunology and bone biology under one umbrella. Osteoporosis is one of the most common inflammatory bone loss condition with more than 200 million individuals affected worldwide. T helper (Th) cells along with various other immune cells are major players involved in bone homeostasis. In the present review, we specifically discuss the role of various defined T lymphocyte subsets (Th cells comprising Th1, Th2, Th9, Th17, Th22, regulatory T cells, follicular helper T cells, natural killer T cells, γδ T cells, and CD8⁺ T cells) in the pathophysiology of osteoporosis. The study of the specific role of immune system in osteoporosis has now been proposed by our group as “immunoporosis: the immunology of osteoporosis” with special emphasis on the role of various subsets of T lymphocytes. The establishment of this new field had been need of the hour due to the emergence of novel roles of various T cell lymphocytes in accelerated bone loss observed during osteoporosis. Activated T cells either directly or indirectly through the secretion of various cytokines and factors modulate bone health and thereby regulate bone remodeling. Several studies have summarized the role of inflammation in pathogenesis of osteoporosis but very few reports had delineated the precise role of various T cell subsets in the pathobiology of osteoporosis. The present review thus for the first time clearly highlights and summarizes the role of various T lymphocytes in the development and pathophysiology of osteoporosis, giving birth to a new field of biology termed as “immunoporosis”. This novel field will thus provide an overview of the nexus between the cellular components of both bone and immune systems, responsible for the observed bone loss in osteoporosis. A molecular insight into the upcoming and novel field of immunoporosis would thus leads to development of innovative approaches for the prevention and treatment of osteoporosis.

Identification of Casz1 as a Regulatory Protein Controlling T Helper Cell Differentiation, Inflammation, and Immunity

While T helper (Th) cells play a crucial role in host defense, an imbalance in Th effector subsets due to dysregulation in their differentiation and expansion contribute to inflammatory disorders. Here, we show that Casz1, whose function is previously unknown in CD4+ T cells, coordinates Th differentiation in vitro and in vivo. Casz1 deficiency in CD4+ T cells lowers susceptibility to experimental autoimmune encephalomyelitis, consistent with the reduced frequency of Th17 cells, despite an increase in Th1 cells in mice. Loss of Casz1 in the context of mucosal Candida infection severely impairs Th17 and Treg responses, and lowers the ability of the mice to clear the secondary infection. Importantly, in both the models, absence of Casz1 causes a significant diminution in IFN-γ+IL-17A+ double-positive inflammatory Th17 cells (Th1* cells) in tissues in vivo. Transcriptome analyses of CD4+ T cells lacking Casz1 show a signature consistent with defective Th17 differentiation. With regards to Th17 differentiation, Casz1 limits repressive histone marks and enables acquisition of permissive histone marks at Rorc, Il17a, Ahr, and Runx1 loci. Taken together, these data identify Casz1 as a new Th plasticity regulator having important clinical implications for autoimmune inflammation and mucosal immunity.

Lumican negatively controls the pathogenicity of murine encephalitic TH17 cells

TH17 cells play an essential role in the development of both human multiple sclerosis and animal experimental autoimmune encephalomyelitis (EAE). Nevertheless, it is not well understood how the pathogenicity of TH17 cells is controlled in the autoimmune neuroinflammation. In vitro, we found Lumican (Lum), an extracellular matrix (ECM) protein, is selectively expressed by TH17 cells among tested murine TH subsets. Lum deficiency leads to earlier onset and enhanced severity of EAE. This enhanced disease in Lum-deficient mice is associated with increased production of IL-17 and IL-21 and decreased TH17 cell apoptosis. Dysregulation in cytokine production appears to be specific to TH17 cells as TH1 and TH2 cell polarization and/or cytokine production were unaltered. Furthermore, adoptive transfer of myelin oligodendrocyte glycoprotein specific TH17 cells derived from Lum-deficient mice led to earlier onset and increased severity of disease compared to controls highlighting a TH17-cell-intrinsic effect of Lum. Taken together, our results suggest that Lum negatively regulates encephalitic TH17 cells, implicating a potential therapeutic pathway in TH17 cell mediated autoimmune and inflammatory diseases.

Lymphocytic, cytokine and transcriptomic profiles in peripheral blood of dogs with atopic dermatitis

Background

Canine atopic dermatitis (cAD) is a common chronic and pruritic skin disease in dogs. The development of cAD involves complex interactions between environmental antigens, genetic predisposition and a number of disparate cell types. The aim of the present study was to perform comprehensive analyses of peripheral blood of AD dogs in relation to healthy subjects in order to determine the changes which would be characteristic for cAD.

Results

The number of cells in specific subpopulations of lymphocytes was analyzed by flow cytometry, concentration of chosen pro- and anti-inflammatory cytokines (IL-4, IL-10, IL-13, TNF-α, TGF-β1) was determined by ELISA; and microarray analysis was performed on RNA samples isolated from peripheral blood nuclear cells of AD and healthy dogs. The number of Th cells (CD3⁺CD4⁺) in AD and healthy dogs was similar, whereas the percentage of Tc (CD3⁺CD8⁺) and Treg (CD4⁺CD25⁺ Foxp3⁺) cells increased significantly in AD dogs. Increased concentrations of IL-13 and TNF-α, and decreased levels of IL-10 and TGF-β1 was observed in AD dogs. The level of IL-4 was similar in both groups of animals. Results of the microarray experiment revealed differentially expressed genes involved in transcriptional regulation (e.g., transcription factors: SMAD2, RORA) or signal transduction pathways (e.g., VEGF, SHB21, PROC) taking part in T lymphocytes lineages differentiation and cytokines synthesis.

Conclusions

Results obtained indicate that CD8⁺ T cells, beside CD4⁺ T lymphocytes, contribute to the development of the allergic response. Increased IL-13 concentration in AD dogs suggests that this cytokine may play more important role than IL-4 in mediating changes induced by allergic inflammation. Furthermore, observed increase in Treg cells in parallel with high concentrations of TNF-α and low levels of IL-10 and TGF-β1 in the peripheral blood of AD dogs point at the functional insufficiency of Treg cells in patients with AD.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-016-0805-6) contains supplementary material, which is available to authorized users.

Cytokine responses in primary and secondary respiratory syncytial virus infections

BACKGROUND

Primary respiratory syncytial virus (RSV) infections are characterized by high levels of IL-8 and an intense neutrophilia. Little is known about the cytokine responses in secondary infections. Preschool children experiencing RSV secondary infections were recruited from the siblings of infants admitted to hospital with RSV acute bronchiolitis.

METHODS

Fifty-one infants with acute bronchiolitis (39 RSV positive, 12 RSV negative) and 20 age-matched control infants were recruited. In addition, seven older siblings of infants from the RSV-positive cohort and confirmed RSV infection were recruited. Samples of nasal secretions were obtained using a flocked swab, and secretions extracted using centrifugation. Cytokine bead array was used to obtain levels of interleukin (IL)-17A, IL-8, IL-6, IL-21, and tumor necrosis factor-α.

RESULTS

Levels of IL-8 and IL-6 were significantly lower in the RSV-positive siblings compared with the RSV-positive infants. There were no significant differences between levels of the other cytokines in the primary and secondary infections.

CONCLUSION

The very high levels of IL-8 and IL-6 response characteristic of the primary RSV infection was not observed in secondary RSV-positive infections and this did not appear to be due to a global reduction in cytokine production.

Dietary phytochemicals modulate skin gene expression profiles and result in reduced lice counts after experimental infection in Atlantic salmon

Background

The use of phytochemicals is a promising solution in biological control against salmon louse (Lepeophtheirus salmonis). Glucosinolates belong to a diverse group of compounds used as protection against herbivores by plants in the family Brassicaceae, while in vertebrates, ingested glucosinolates exert health-promoting effects due to their antioxidant and detoxifying properties as well as effects on cell proliferation and growth. The aim of this study was to investigate if Atlantic salmon fed two different doses of glucosinolate-enriched feeds would be protected against lice infection. The effects of feeding high dose of glucosinolates before the infection, and of high and low doses five weeks into the infection were studied.

Methods

Skin was screened by 15 k oligonucleotide microarray and qPCR.

Results

A 25 % reduction (P < 0.05) in lice counts was obtained in the low dose group and a 17 % reduction in the high dose group compared to fish fed control feed. Microarray analysis revealed induction of over 50 interferon (IFN)-related genes prior to lice infection. Genes upregulated five weeks into the infection in glucosinolate-enriched dietary groups included Type 1 pro-inflammatory factors, antimicrobial and acute phase proteins, extracellular matrix remodeling proteases and iron homeostasis regulators. In contrast, genes involved in muscle contraction, lipid and glucose metabolism were found more highly expressed in the skin of infected control fish.

Conclusions

Atlantic salmon fed glucosinolates had a significantly lower number of sea lice at the end of the experimental challenge. Feeding glucosinolates coincided with increased expression of IFN-related genes, and higher expression profiles of Type 1 immune genes late into the infection. In addition, regulation of genes involved in the metabolism of iron, lipid and sugar suggested an interplay between metabolism of nutrients and mechanisms of resistance.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-016-1537-y) contains supplementary material, which is available to authorized users.

Transforming growth factor-β, interleukin-17, and IL-23 gene expression profiles associated with human peri-implantitis

OBJECTIVES

The mRNA expression profiles of IL-23/Th17 and the Treg-associated cytokine TGF-β in peri-implantitis are currently under research. This study characterized the IL-17, IL-23, and TGF-β gene expression levels in healthy and diseased peri-implant tissues and correlated these data with radiographic bone loss.

MATERIAL AND METHODS

Peri-implant soft tissues from 40 subjects (20 healthy controls with mean age of 59.4 ± 6.3, and 20 with peri-implantitis with mean age of 56.6 ± 5.5) were enrolled in this study, and real-time PCR (RT-PCR) was used to define the profile of IL-17, IL-23, and TGF-β gene expression.

RESULTS

Higher levels of TGF-β mRNA were observed in biopsies taken from healthy controls, and the IL-23 mRNA levels were significantly increased in the peri-implantitis group (P < 0.0001). No differences in IL-17 mRNA levels were observed between the two groups (P > 0.05).

CONCLUSIONS

Data presented in this report demonstrated a predominant Th17 response in peri-implantitis subjects based on the higher levels of IL-23 and lower levels of TGF-β detected.

Immunoexpression of Th17-related cytokines in oral lichen planus

A recently described lineage of lymphocytes, Th17 cells, has been associated with inflammatory and autoimmune diseases. The aim of this article was to assess the immunoexpression of cytokines related to this lineage, interleukin-17 (IL-17) and IL-23 and in reticular and erosive oral lichen planus (OLP). The sample included 41 cases of OLP (23 reticular and 18 erosive) and 10 cases of inflammatory fibrous hyperplasia (IFH). Lymphocytes exhibiting cytoplasmic immunostaining were counted. Epithelial immunostaining was also evaluated. There was no statistical differences in the number of IL-17 and IL-23 lymphocytes between the OLP (55.40 and 48.40, respectively) and IFH (39.30 and 44.40, respectively). A significantly higher number of IL-23 lymphocytes was found in erosive OLP group (63.80) when compared with reticular (41.40) and IFH lesions (44.40) (P=0.019). Furthermore, epithelial immunopositivity for IL-17 and IL-23 was higher in OLP lesions than in IFH (P=0.012 and P=0.011, respectively). A significantly higher number of IL-23 lymphocytes in erosive OLP and the strong epithelial immunopositivity for IL-23 and IL-17 in OLP group could suggest an important participation of TCD4 Th17 response in this disorder.

B Cell-Activating Transcription Factor Plays a Critical Role in the Pathogenesis of Anti-Major Histocompatibility Complex-Induced Obliterative Airway Disease

Antibodies (Abs) against major histocompatibility complex (MHC) results in T helper-17 (Th17)-mediated immunity against lung self-antigens (SAgs), K-α1 tubulin and collagen V and obliterative airway disease (OAD). Because B cell-activating transcription factor (BATF) controls Th17 and autoimmunity, we proposed that BATF may play a critical role in OAD. Anti-H2K(b) was administered intrabronchially into Batf (-/-) and C57BL/6 mice. Histopathology of the lungs on days 30 and 45 after Ab administration to Batf (-/-) mice resulted in decreased cellular infiltration, epithelial metaplasia, fibrosis, and obstruction. There was lack of Abs to SAgs, reduction of Sag-specific interleukin (IL)-17 T cells, IL-6, IL-23, IL-17, IL-1β, fibroblast growth factor-6, and CXCL12 and decreased Janus kinase 2, signal transducer and activator of transcription 3 (STAT3), and retinoid-related orphan receptor γT. Further, micro-RNA (miR)-301a, a regulator of Th17, was reduced in Batf (-/-) mice in contrast to upregulation of miR-301a and downregulation of protein inhibitor of activated STAT3 (PIAS3) in anti-MHC-induced OAD animals. We also demonstrate an increase in miR-301a in the bronchoalveolar lavage cells from lung transplant recipients with Abs to human leukocyte antigen. This was accompanied by reduction in PIAS3 mRNA. Therefore, we conclude that BATF plays a critical role in the immune responses to SAgs and pathogenesis of anti-MHC-induced rejection. Targeting BATF should be considered for preventing chronic rejection after human lung transplantation.

NAD(+) regulates Treg cell fate and promotes allograft survival via a systemic IL-10 production that is CD4(+) CD25(+) Foxp3(+) T cells independent

CD4⁺ CD25⁺ Foxp3⁺ Tregs have been shown to play a central role in immune homeostasis while preventing from fatal inflammatory responses, while Th17 cells have traditionally been recognized as pro-inflammatory mediators implicated in a myriad of diseases. Studies have shown the potential of Tregs to convert into Th17 cells, and Th17 cells into Tregs. Increasing evidence have pointed out CD25 as a key molecule during this transdifferentiation process, however molecules that allow such development remain unknown. Here, we investigated the impact of NAD⁺ on the fate of CD4⁺ CD25⁺ Foxp3⁺ Tregs in-depth, dissected their transcriptional signature profile and explored mechanisms underlying their conversion into IL-17A producing cells. Our results demonstrate that NAD⁺ promotes Treg conversion into Th17 cells in vitro and in vivo via CD25 cell surface marker. Despite the reduced number of Tregs, known to promote homeostasis, and an increased number of pro-inflammatory Th17 cells, NAD⁺ was able to promote an impressive allograft survival through a robust systemic IL-10 production that was CD4⁺ CD25⁺ Foxp3⁺ independent. Collectively, our study unravels a novel immunoregulatory mechanism of NAD⁺ that regulates Tregs fate while promoting allograft survival that may have clinical applications in alloimmunity and in a wide spectrum of inflammatory conditions.

The Role of IL-17 and TH17 Cells in the Bone Catabolic Activity of PTH

Osteoimmunology is field of research dedicated to the study of the interactions between the immune system and bone. Among the cells of the immune system that regulate the skeleton in health and disease are T lymphocytes, T cells secrete inflammatory/osteoclastogenic cytokines such as RANKL, TNF, and IL-17, as well as factors that stimulate bone formation, including Wnt ligands. In addition, T cells regulate the differentiation and life span of stromal cells via CD40L and other costimulatory molecules expressed on their surface. Consensus exists that parathyroid hormone (PTH) induces bone loss by increasing the production of RANKL by osteocytes and osteoblast. However, new evidence suggests that PTH expands Th17 cells and increases IL-17 levels in mice and humans. Studies in the mouse of further shown that Th17 cell produced IL-17 acts as an “upstream cytokine” that increases the sensitivity of osteoblasts and osteocytes to PTH. As a result, PTH stimulates osteocytic and osteoblastic release of RANKL. Therefore, PTH cause bone loss only in the presence of IL-17 signaling. This article reviews the evidence that the effects of PTH are mediated not only by osteoblasts and osteocytes, but also T cells and IL-17.

T cells, osteoblasts, and osteocytes: interacting lineages key for the bone anabolic and catabolic activities of parathyroid hormone

Osteoimmunology is a field of research dedicated to the study of the interactions between the immune system and bone. Among the cells of the immune system that regulate bone turnover and the responsiveness of bone cells to calciothropic hormones are bone marrow T lymphocytes. T cells secrete osteoclastogenic cytokines such as RANKL and TNF-α, as well as factors that stimulate bone formation, one of which is Wnt10b. In addition, T cells regulate the differentiation and life span of stromal cells (SCs) and their responsiveness to parathyroid hormone (PTH) via costimulatory molecules expressed on their surface. The conditioning effect of T cells on SCs is inherited by the osteoblastic and osteocytic progeny of SCs. As a result, osteoblastic cells of T cell-deficient mice have functional characteristics different from corresponding cells of T cell-replete mice. These differences include the ratio of RANKL/OPG produced in response to continuous PTH treatment, and the osteoblastogenic response to intermittent PTH treatment. This article reviews the evidence indicating that the effects of PTH are mediated not only by osteoblasts and osteocytes but also by T cells.

IL-17A Is Increased in Humans with Primary Hyperparathyroidism and Mediates PTH-Induced Bone Loss in Mice

Primary hyperparathyroidism (PHPT) is a common cause of bone loss that is modeled by continuous PTH (cPTH) infusion. Here we show that the inflammatory cytokine IL-17A is upregulated by PHPT in humans and cPTH in mice. In humans, IL-17A is normalized by parathyroidectomy. In mice, treatment with anti-IL-17A antibody and silencing of IL-17A receptor IL-17RA prevent cPTH-induced osteocytic and osteoblastic RANKL production and bone loss. Mechanistically, cPTH stimulates conventional T cell production of TNFα (TNF), which increases the differentiation of IL-17A-producing Th17 cells via TNF receptor 1 (TNFR1) signaling in CD4(+) cells. Moreover, cPTH enhances the sensitivity of naive CD4(+) cells to TNF via GαS/cAMP/Ca(2+) signaling. Accordingly, conditional deletion of GαS in CD4(+) cells and treatment with the calcium channel blocker diltiazem prevents Th17 cell expansion and blocks cPTH-induced bone loss. Neutralization of IL-17A and calcium channel blockers may thus represent novel therapeutic strategies for hyperparathyroidism.

Interleukin17A Promotes Postoperative Cognitive Dysfunction by Triggering β-Amyloid Accumulation via the Transforming Growth Factor-β (TGFβ)/Smad Signaling Pathway

Although postoperative cognitive dysfunction (POCD) is relatively common in elderly patients who have undergone major surgery, the mechanisms underlying this postoperative complication are unclear. Previously, we have investigated the role of cytokine-mediated hippocampal inflammation in the development of POCD in a rat model. Here, we sought to determine in mice the role of cytokine interleukin17A (IL17A) in POCD and to characterize the associated signaling pathways. Old mice underwent hepatectomy surgery in the presence or absence of IL17A monoclonal antibody, and cognitive function, hippocampal neuroinflammation, and pathologic markers of Alzheimer’s disease (AD) were assessed. We found that the level of IL17A in the hippocampus was increased in hepatectomy mice and that cognitive impairment after surgery was associated with the appearance of certain pathological hallmarks of AD: activation of astrocytes, β-amyloid_1-42 (Aβ_1–42) production, upregulation of transforming growth factor-β (TGFβ), and increased phosphorylation of signaling mother against decapentaplegic peptide 3 (Smad3) protein in the hippocampus. Surgery-induced changes in cognitive dysfunction and changes in Aβ_1–42 and TGFβ/Smad signaling were prevented by the administration of IL17A monoclonal antibody. In addition, IL17A-stimulated TGFβ/Smad activation and Aβ_1–42 expression were reversed by IL17A receptor small interfering RNA and a TGFβ receptor inhibitor in cultured astrocytes. Our findings suggest that surgery can provoke IL17A-related hippocampal damage, as characterized by activation of astrocytes and TGFβ/Smad pathway dependent Aβ_1–42 accumulation in old subjects. These changes likely contribute to the cognitive decline seen in POCD.

Proteomic and epigenomic markers of sepsis-induced delirium (SID)

In elderly population sepsis is one of the leading causes of intensive care unit (ICU) admissions in the United States. Sepsis-induced delirium (SID) is the most frequent cause of delirium in ICU (Martin et al., 2010). Together delirium and SID represent under-recognized public health problems which place an increasing financial burden on the US health care system, currently estimated at 143-152 billion dollars per year (Leslie et al., 2008). The interest in SID was recently reignited as it was demonstrated that, contrary to prior beliefs, cognitive deficits induced by this condition may be irreversible and lead to dementia (Pandharipande et al., 2013; Brummel et al., 2014). Conversely, it is construed that diagnosing SID early or mitigating its full blown manifestations may preempt geriatric cognitive disorders. Biological markers specific for sepsis and SID would facilitate the development of potential therapies, monitor the disease process and at the same time enable elderly individuals to make better informed decisions regarding surgeries which may pose the risk of complications, including sepsis and delirium. This article proposes a battery of peripheral blood markers to be used for diagnostic and prognostic purposes in sepsis and SID. Though each individual marker may not be specific enough, we believe that together as a battery they may achieve the necessary accuracy to answer two important questions: who may be vulnerable to the development of sepsis, and who may develop SID and irreversible cognitive deficits following sepsis?

Non-Neuronal Acetylcholine: The Missing Link Between Sepsis, Cancer, and Delirium?

The interaction between living organisms and the environment requires a balancing act between genomic and epigenomic forces. Inflammation and cellular proliferation are kept in check by the genes, which code for their components and the microRNAs, which are capable of silencing the transcription of these genes. Acetylcholine (ACh) may play a unique role in the maintenance of this equilibrium, as the epigenomic inhibition of the gene coding for nicotinic receptors, and disinhibits the gene causing anergia in immune cells. We hypothesize that age-induced ACh deficiency is the result of an epigenomic dysfunction of microRNA-6775 (miR-6775), which silences the transcription of CHRNA7 gene [coding for alpha 7 nicotinic cholinergic receptors (nAChRs)]. When silenced, this gene induces decreased expression of alpha 7 nAChRs, which may predispose elderly individuals to inflammation, neuroinflammation, and delirium. We hypothesize further that miR-6775-induced hypocholinergia augments the expression of RNF 128, the gene related to anergy in lymphocytes (GRAIL). This gene favors regulatory T cells (Tregs), promoters of immunologic tolerance, which may predispose to both cancer and sepsis-induced immunosuppression.

RORγt(+) hematopoietic cells are necessary for tumor cell proliferation during colitis-associated tumorigenesis in mice

Colorectal cancer (CRC) is one of the most common tumor entities. In patients with inflammatory bowel diseases, the development of colitis-associated colon cancer is considered a dangerous long-term complication. IL-17A and the transcription factor retinoic acid receptor-related orphan receptor γt (RORγt) play fundamental roles in the pathogenesis of inflammatory bowel diseases; in human studies, we detected a dense infiltration of RORγt-dependent CD4(+) IL17A(+) T helper (Th)17 cells in specimens of CRC, ulcerative colitis, and ulcerative colitis-associated colorectal cancer. However, the mechanistic role of RORγt(+) hematopoietic cells in colitis-associated tumorigenesis remains unclear. To investigate colitis-associated colon tumorigenesis, we conducted studies in the AOM+DSS mouse model that revealed the importance of RORγt for colon tumor progression. In the absence of RORγt-dependent Th17 lymphocytes, mice showed signs of intense chronic colitis, but developed significantly fewer macroscopic tumor nodules. The reduction of tumor development in RORγt(-/-) mice was not due to reduced colon tumor initiation. However, the proliferation rate of tumor cells was reduced in the absence of RORγt-dependent Th17 cells and tumor cells showed pronounced signs of senescence-associated epigenetic and lysosomal changes. These results indicate an important role for the immunological milieu in colitis-associated cancer, which is shaped in-part by RORγt-dependent Th17 lymphocytes that support CRC growth.

Mechanisms of immune response regulation in lung cancer

Lung cancer is a leading cause of cancer deaths. As a solid tumor with low antigenicity and heterogenic phenotype lung cancer evades host immune defense. The cytotoxic anticancer effect is suppressed by a complex mechanism in tumor microenvironment. The population of regulatory T cells (Tregs) plays a crucial role in this inhibition of immune response. Tregs are defined by presence of forkhead box P3 (Foxp3) molecule. The high expression of Foxp3 was found in lung cancer cells and in tumor infiltrating lymphocytes (TIL). Cytotoxic T-lymphocyte antigen 4 (CTLA4) is constitutively expressed on Tregs and suppresses T cell activation. The elevated CTLA4 expression in lymphocytes in patients with lung cancer was found. Recently the antibodies blocking CTLA4 showed some clinical efficacy in patients with lung cancer. Cancer cells and immune cells release many cytokines capable to show suppressive immune effect in cancer microenvironment. The most active are transforming growth factorβ (TGFβ) and IL-10. The pleiotropic function of Th17 population is TGFβ related. The myeloid lineage of suppressor cells in lung cancer is represented by tumor associated macrophages (TAM) with phenotype of M2 macrophages and some regulatory properties with releasing amounts of IL-10 and TGFβ. The myeloid derived suppressor cells (MDSCs) control cytotoxic T cell activity in mechanisms which are highly dependent on the context of tumor environment. The mechanisms of anticancer immune response regulation need further investigation as an important target to new way of treatment.

IL-34- and M-CSF-induced macrophages switch memory T cells into Th17 cells via membrane IL-1α

Macrophages orchestrate the immune response via the polarization of CD4(+) T helper (Th) cells. Different subsets of macrophages with distinct phenotypes, and sometimes opposite functions, have been described. M-CSF and IL-34 induce the differentiation of monocytes into IL-10(high) IL-12(low) immunoregulatory macrophages, which are similar to tumor-associated macrophages (TAMs) in ovarian cancer. In this study, we evaluated the capacity of human macrophages induced in the presence of M-CSF (M-CSF macrophages) or IL-34 (IL-34 macrophages) and ovarian cancer TAMs to modulate the phenotype of human CD4(+) T cells. Taken together, our results show that M-CSF-, IL-34 macrophages, and TAMs switch non-Th17 committed memory CD4(+) T cells into conventional CCR4(+) CCR6(+) CD161(+) Th17 cells, expressing or not IFN-gamma. Contrary, the pro-inflammatory GM-CSF macrophages promote Th1 cells. The polarization of memory T cells into Th17 cells is mediated via membrane IL-1α (mIL-1α), which is constitutively expressed by M-CSF-, IL-34 macrophages, and TAMs. This study elucidates a new mechanism that allows macrophages to maintain locally restrained and smoldering inflammation, which is required in angiogenesis and metastasis.

Development of a unique epigenetic signature during in vivo Th17 differentiation

Activated naive CD4⁺ T cells are highly plastic cells that can differentiate into various T helper (Th) cell fates characterized by the expression of effector cytokines like IFN-γ (Th1), IL-4 (Th2) or IL-17A (Th17). Although previous studies have demonstrated that epigenetic mechanisms including DNA demethylation can stabilize effector cytokine expression, a comprehensive analysis of the changes in the DNA methylation pattern during differentiation of naive T cells into Th cell subsets is lacking. Hence, we here performed a genome-wide methylome analysis of ex vivo isolated naive CD4⁺ T cells, Th1 and Th17 cells. We could demonstrate that naive CD4⁺ T cells share more demethylated regions with Th17 cells when compared to Th1 cells, and that overall Th17 cells display the highest number of demethylated regions, findings which are in line with the previously reported plasticity of Th17 cells. We could identify seven regions located in Il17a, Zfp362, Ccr6, Acsbg1, Dpp4, Rora and Dclk1 showing pronounced demethylation selectively in ex vivo isolated Th17 cells when compared to other ex vivo isolated Th cell subsets and in vitro generated Th17 cells, suggesting that this unique epigenetic signature allows identifying and functionally characterizing in vivo generated Th17 cells.

Tumorigenic Th17 cells in oncogenic Kras-driven and inflammation-accelerated lung cancer

Although inflammation has been linked to lung cancer pathogenesis, very little is known about the critical players during lung cancer development. We found that Kras mutation in lung epithelial cells preferentially leads to recruitment of Th17 cells, which produce IL-17, a signature cytokine that promotes inflammation. We demonstrated IL-17 is critical for tumor growth in part by recruiting tumorigenic GR1+ CD11b+ cells.

Spatial and temporal colonization dynamics of segmented filamentous bacteria is influenced by gender, age and experimental infection with Helicobacter hepaticus in Swiss Webster mice

In this study, we examined colonization dynamics of segmented filamentous bacteria (SFB) in intestine of Swiss Webster (SW) mice infected with Helicobacter hepaticus (Hh). At 8 weeks post-inoculation with Hh (WPI), cecal and colonic SFB levels in the control males were significantly lower compared to those at 16 WPI. Hh infection in both genders did not alter SFB levels in the jejunum and ileum, but increased SFB levels in the cecum and colon of males compared to the controls (P < 0.05) at 8 WPI. At 16 WPI, the Hh-infected females contained lower levels of SFB in the jejunum, cecum and colon compared to the female controls. Irrespective of gender, aging and Hh infection, the Il-17A mRNA levels decreased from the small intestine to the cecum and then to the colon, whereas the Foxp3 mRNA levels were comparable in these intestinal regions. There were significant differences in Il-17A mRNA levels in the ileum (P < 0.05, R(2) = 0.31), with females having greater Il-17A mRNA levels than males, and higher SFB colonization levels related to more Il-17A mRNA. These results indicate that aging and gender play an important role in colonization dynamics of intestinal SFB and ileal SFB-associated Th17 response.

NAD+ protects against EAE by regulating CD4+ T-cell differentiation

CD4(+) T cells are involved in the development of autoimmunity, including multiple sclerosis (MS). Here we show that nicotinamide adenine dinucleotide (NAD(+)) blocks experimental autoimmune encephalomyelitis (EAE), a mouse model of MS, by inducing immune homeostasis through CD4(+)IFNγ(+)IL-10(+) T cells and reverses disease progression by restoring tissue integrity via remyelination and neuroregeneration. We show that NAD(+) regulates CD4(+) T-cell differentiation through tryptophan hydroxylase-1 (Tph1), independently of well-established transcription factors. In the presence of NAD(+), the frequency of T-bet(-/-) CD4(+)IFNγ(+) T cells was twofold higher than wild-type CD4(+) T cells cultured in conventional T helper 1 polarizing conditions. Our findings unravel a new pathway orchestrating CD4(+) T-cell differentiation and demonstrate that NAD(+) may serve as a powerful therapeutic agent for the treatment of autoimmune and other diseases.

Analysis of humoral immune response and cytokines in chickens vaccinated with Eimeria brunetti apical membrane antigen-1 (EbAMA1) DNA vaccine

This study aimed to determine the changes of cytokines, specific serum IgG and several parameters in chickens vaccinated with DNA vaccine encoding Eimeria brunetti apical membrane antigen-1 (EbAMA1) antigen. Two-week-old chickens were divided into five groups (four groups for experiment) randomly. Experimental groups of chickens were immunized with DNA vaccine while control group of chickens were injected with pVAX1 plasmid alone or TE buffer solution. All immunizations were boosted 2 weeks later. The EbAMA1 specific IgG antibody responses were measured at weeks 1-6 post-second immunizations and several parameters were also identified. The result showed that the antibody titers in chickens vaccinated with DNA vaccines were significantly different from those of the control groups 1 week after the second immunization and reached the maximum values 3 weeks post-second immunization. IFN-γ concentration was increased the highest level against EbAMA1 of all chickens vaccinated with vaccines up to 56-fold, follow by the specific IgG antibody levels were increased 10-17-fold compared with those of TE solution and plasmid (pVAX1) control chickens 1-6 weeks post-second immunization. In case of the levels of IL-10 and IL-17 was increased in experimental chickens with 4-5-fold. Even though it was statistically significant, TGF-β and IL-4 levels were higher in vaccinated than unvaccinated chickens. The results suggested that DNA vaccines encoding E. brunetti apical membrane antigen-1 (EbAMA1) could increase serum specific IgG antibody and cytokines concentration and could give protection against E. brunetti infection.

Mechanisms of immune response regulation in lung cancer

Lung cancer is a leading cause of cancer deaths. As a solid tumor with low antigenicity and heterogenic phenotype lung cancer evades host immune defense. The cytotoxic anticancer effect is suppressed by a complex mechanism in tumor microenvironment. The population of regulatory T cells (Tregs) plays a crucial role in this inhibition of immune response. Tregs are defined by presence of forkhead box P3 (Foxp3) molecule. The high expression of Foxp3 was found in lung cancer cells and in tumor infiltrating lymphocytes (TIL). Cytotoxic T-lymphocyte antigen 4 (CTLA4) is constitutively expressed on Tregs and suppresses T cell activation. The elevated CTLA4 expression in lymphocytes in patients with lung cancer was found. Recently the antibodies blocking CTLA4 showed some clinical efficacy in patients with lung cancer. Cancer cells and immune cells release many cytokines capable to show suppressive immune effect in cancer microenvironment. The most active are transforming growth factorβ (TGFβ) and IL-10. The pleiotropic function of Th17 population is TGFβ related. The myeloid lineage of suppressor cells in lung cancer is represented by tumor associated macrophages (TAM) with phenotype of M2 macrophages and some regulatory properties with releasing amounts of IL-10 and TGFβ. The myeloid derived suppressor cells (MDSCs) control cytotoxic T cell activity in mechanisms which are highly dependent on the context of tumor environment. The mechanisms of anticancer immune response regulation need further investigation as an important target to new way of treatment.

Effects of traumatic brain injury on intestinal contractility

BACKGROUND

Patients with traumatic brain injury (TBI) often suffer from gastrointestinal dysfunction including intolerance to enteral feedings. However, it is unclear how TBI affects small intestinal contractile activity. The purpose of this study was to determine if TBI affects intestinal smooth muscle function.

METHODS

Sprague-Dawley rats were subjected to controlled cortical impact injury (TBI). Sham animals underwent a similar surgery but no injury (SHAM). Animals were sacrificed 1, 3, and 7 days after TBI and intestinal smooth muscle tissue was collected for measurement of contractile activity and transit, NF-kB activity, and cytokine levels. Brains were collected after sacrifice to determine volume loss due to injury.

KEY RESULTS

Contractile activity decreased significantly in ileum, but not jejunum, in the TBI group 7 days after injury compared with SHAM. Brain volume loss increased significantly 7 days after injury compared with 3 days and correlated significantly with the contractile activity 1 day after injury. In the intestinal smooth muscle, NF-kB activity increased significantly in the TBI group 3 and 7 days after injury vs SHAM. Wet to dry weight ratio, indicating edema, also increased significantly in the TBI group. Interleukin-1α, -1β, and -17 increased significantly in the TBI group compared with SHAM.

CONCLUSIONS & INFERENCES

Traumatic brain injury causes a delayed but significant decrease in intestinal contractile activity in the ileum leading to delayed transit. The decreased intestinal contractile activity is attributed to secondary inflammatory injury as evidenced by increased NF-kB activity, increased edema, and increased inflammatory cytokines in the intestinal smooth muscle.