Forkhead-box transcription factors and their role in the immune system

Eupatilin ameliorates collagen induced arthritis

Eupatilin is the main active component of DA-9601, an extract from Artemisia. Recently, eupatilin was reported to have anti-inflammatory properties. We investigated the anti-arthritic effect of eupatilin in a murine arthritis model and human rheumatoid synoviocytes. DA-9601 was injected into collagen-induced arthritis (CIA) mice. Arthritis score was regularly evaluated. Mouse monocytes were differentiated into osteoclasts when eupatilin was added simultaneously. Osteoclasts were stained with tartrate-resistant acid phosphatase and then manually counted. Rheumatoid synoviocytes were stimulated with TNF-α and then treated with eupatilin, and the levels of IL-6 and IL-1β mRNA expression in synoviocytes were measured by RT-PCR. Intraperitoneal injection of DA-9601 reduced arthritis scores in CIA mice. TNF-α treatment of synoviocytes increased the expression of IL-6 and IL-1β mRNAs, which was inhibited by eupatilin. Eupatilin decreased the number of osteoclasts in a concentration dependent manner. These findings, showing that eupatilin and DA-9601 inhibited the expression of inflammatory cytokines and the differentiation of osteoclasts, suggest that eupatilin and DA-9601 is a candidate anti-inflammatory agent.

FOXP3 suppresses breast cancer metastasis through downregulation of CD44

Forkhead box protein 3 (FOXP3) plays an important role in breast cancer as an X-linked tumor suppressor gene. However, the biological functions and significance of FOXP3 in breast cancer metastasis remain unclear. Here, we find that, clinically, nuclear FOXP3 expression is inversely correlated with breast cancer metastasis. Moreover, we demonstrate that FOXP3 significantly inhibits adhesion, invasion and metastasis of breast cancer cells in vivo and in vitro. In addition, the adhesion molecule CD44 is found to be suppressed by FOXP3 through transcriptome sequence analysis (RNA-seq). A luciferase reporter assay, chromatin immunoprecipitation and electrophoretic mobility shift assay identify CD44 as a direct target of FOXP3. The expression of CD44 is downregulated by FOXP3 in breast cancer cells. Importantly, anti-CD44 antibody reverses the FOXP3 siRNA-induced effects on the breast cancer cells in vitro and FOXP3 expression level in the nucleus of breast cancer cells is inversely correlated with CD44 expression level in clinic breast cancer tissues. Taken together, the results from the present study suggest that FOXP3 is a suppressor of breast cancer metastasis. FOXP3 directly binds to the promoter of CD44 and inhibits its protein expression, thereby suppressing adhesion and invasion of human breast cancer cells. This finding highlights the therapeutic potential of FOXP3-CD44 signaling to inhibit breast cancer metastasis.

Cinnamon ameliorates experimental allergic encephalomyelitis in mice via regulatory T cells: implications for multiple sclerosis therapy

Upregulation and/or maintenance of regulatory T cells (Tregs) during an autoimmune insult may have therapeutic efficacy in autoimmune diseases. Although several immunomodulatory drugs and molecules are available, most present significant side effects over long-term use. Cinnamon is a commonly used natural spice and flavoring material used for centuries throughout the world. Here, we have explored a novel use of cinnamon powder in protecting Tregs and treating the disease process of experimental allergic encephalomyelitis (EAE), an animal model of MS. Oral feeding of cinnamon (Cinnamonum verum) powder suppresses clinical symptoms of relapsing-remitting EAE in female PLP-TCR transgenic mice and adoptive transfer mouse model. Cinnamon also inhibited clinical symptoms of chronic EAE in male C57/BL6 mice. Dose-dependent study shows that cinnamon powder at a dose of 50 mg/kg body wt/d or higher significantly suppresses clinical symptoms of EAE in mice. Accordingly, oral administration of cinnamon also inhibited perivascular cuffing, maintained the integrity of blood-brain barrier and blood-spinal cord barrier, suppressed inflammation, normalized the expression of myelin genes, and blocked demyelination in the central nervous system of EAE mice. Interestingly, cinnamon treatment upregulated Tregs via reduction of nitric oxide production. Furthermore, we demonstrate that blocking of Tregs by neutralizing antibodies against CD25 abrogates cinnamon-mediated protection of EAE. Taken together, our results suggest that oral administration of cinnamon powder may be beneficial in MS patients and that no other existing anti-MS therapies could be so economical and trouble-free as this approach.

Assembly and Function of the Precursor B-Cell Receptor

During early stages of development, precursor B lymphocytes express a characteristic type of antigen receptor known as the pre-B-cell receptor (pre-BCR). This receptor differs from conventional BCRs in that it possesses a germ line-encoded surrogate light chain (SLC), which is associated with the signal transduction machinery via heavy chain (HC) proteins that have been generated by productive rearrangement of the immunoglobulin HC genes. The pre-BCR marks a key step of B-cell commitment, as it activates the B-cell-specific signaling cascade and mediates the selection, expansion, and differentiation of cells expressing a productively rearranged HC protein. Another difference between the pre-BCR and conventional BCR might be the initial event that triggers receptor activation, as the pre-BCR is activated in the absence of external ligands, while conventional BCRs require antigen for activation. Nonetheless, the pre-BCR downstream signaling cascade is largely similar to that of the BCR suggesting that the characteristic LC of the pre-BCR mediates important receptor interactions thereby providing distinctive, germ line-encoded features to the pre-BCR. In fact, the SLC enables the pre-BCR to act as a surrogate autoreactive receptor. Here, we outline the structure and function of the pre-BCR and how the autonomous signaling capacity might be a direct consequence of pre-BCR assembly. In addition to its role in early B-cell development, we discuss how the ordered activation of downstream signaling cascades enables the pre-BCR to activate seemingly opposing cellular programs such as proliferation and differentiation.

Suppression of Foxo1 activity and down-modulation of CD62L (L-selectin) in HIV-1 infected resting CD4 T cells

HIV-1 hijacks and disrupts many processes in the cells it infects in order to suppress antiviral immunity and to facilitate its replication. Resting CD4 T cells are important early targets of HIV-1 infection in which HIV-1 must overcome intrinsic barriers to viral replication. Although resting CD4 T cells are refractory to infection in vitro, local environmental factors within lymphoid and mucosal tissues such as cytokines facilitate viral replication while maintaining the resting state. These factors can be utilized in vitro to study HIV-1 replication in resting CD4 T cells. In vivo, the migration of resting naïve and central memory T cells into lymphoid tissues is dependent upon expression of CD62L (L-selectin), a receptor that is subsequently down-modulated following T cell activation. CD62L gene transcription is maintained in resting T cells by Foxo1 and KLF2, transcription factors that maintain T cell quiescence and which regulate additional cellular processes including survival, migration, and differentiation. Here we report that HIV-1 down-modulates CD62L in productively infected naïve and memory resting CD4 T cells while suppressing Foxo1 activity and the expression of KLF2 mRNA. Partial T cell activation was further evident as an increase in CD69 expression. Several other Foxo1- and KLF2-regulated mRNA were increased or decreased in productively infected CD4 T cells, including IL-7rα, Myc, CCR5, Fam65b, S1P₁ (EDG1), CD52, Cyclin D2 and p21^CIP1, indicating a profound reprogramming of these cells. The Foxo1 inhibitor AS1842856 accelerated de novo viral gene expression and the sequella of infection, supporting the notion that HIV-1 suppression of Foxo1 activity may be a strategy to promote replication in resting CD4 T cells. As Foxo1 is an investigative cancer therapy target, the development of Foxo1 interventions may assist the quest to specifically suppress or activate HIV-1 replication in vivo.

Identification of a single nucleotide promoter polymorphism regulating the transcription of ubiquitin specific protease 18 gene related to the resistance to porcine reproductive and respiratory syndrome virus infection

Porcine reproductive and respiratory syndrome (PRRS), characterized by reproductive failure in sows and respiratory disease and mortality in piglets, is a major infectious disease that causes great economic loss throughout the world. Previous studies revealed that the overexpression of porcine ubiquitin specific protease 18 (USP18) gene inhibits PRRSV replication in vitro. The objective of this study is to compare the promoter activity of USP18 in Chinese indigenous Dapulian (DPL) pigs and Duroc×Landrace×Yorkshire (DLY) commercial pigs and screen single nucleotide polymorphism (SNP) affecting porcine USP18 transcription. We found that the promoter activity was significantly higher in DPL pigs than DLY commercial pigs (p<0.05), deletion of the promoter from -1790 to -1314bp decreased the transcriptional activity by roughly 60% (p<0.05) and a SNP G-1533A in this region increased the mRNA expression both prior to and post PRRSV infection in MARC-145 cells. Population genetics analysis showed that allele A was only detected in Chinese pig breeds which are generally resistant to PRRSV. These results suggest that the SNP G-1533A polymorphism in the promoter region of porcine USP18 gene is a potential DNA marker for the resistance to PRRSV.

Expression and DNA methylation of TNF, IFNG and FOXP3 in colorectal cancer and their prognostic significance

BACKGROUND

Colorectal cancer (CRC) progression is associated with suppression of host cell-mediated immunity and local immune escape mechanisms. Our aim was to assess the immune function in terms of expression of TNF, IFNG and FOXP3 in CRC.

METHODS

Sixty patients with CRC and 15 matched controls were recruited. TaqMan quantitative PCR and methylation-specific PCR was performed for expression and DNA methylation analysis of TNF, IFNG and FOXP3. Survival analysis was performed over a median follow-up of 48 months.

RESULTS

TNF was suppressed in tumour and IFNG was suppressed in peripheral blood mononuclear cells (PBMCs) of patients with CRC. Tumours showed enhanced expression of FOXP3 and was significantly higher when tumour size was >38 mm (median tumour size; P=0.006, Mann-Whitney U-test). Peripheral blood mononuclear cell IFNG was suppressed in recurrent CRC (P=0.01). Methylated TNFpromoter (P=0.003) and TNFexon1 (P=0.001) were associated with significant suppression of TNF in tumours. Methylated FOXP3cpg was associated with significant suppression of FOXP3 in both PBMC (P=0.018) and tumours (P=0.010). Reduced PBMC FOXP3 expression was associated with significantly worse overall survival (HR=8.319, P=0.019).

CONCLUSIONS

We have detected changes in the expression of immunomodulatory genes that could act as biomarkers for prognosis and future immunotherapeutic strategies.

Genome-wide identification, phylogeny, and gonadal expression of fox genes in Nile tilapia, Oreochromis niloticus

The fox genes play important roles in various biological processes, including sexual development. In the present study, we isolated 65 fox genes, belonging to 18 subfamilies named A-R, from Nile tilapia through genome-wide screening. Twenty-four of them have two or three (foxm1) copies. Furthermore, 16, 25, 68, and 45 fox members were isolated from nematodes, protochordates, teleosts, and tetrapods, respectively. Phylogenetic analyses indicated fox gene family had undergone three expansions parallel to the three rounds of genome duplication during evolution. We also analyzed the clustered fox genes and found that apparent linkage duplication existed in teleosts, which further supported fish-specific genome duplication hypothesis. In addition, species- and lineage-specific duplication is another reason for fox gene family expansion. Based on the four pairs of XX and XY gonadal transcriptome data from four critical developmental stages, we analyzed the expression profile of all fox genes and identified sexually dimorphic fox genes at each stage. All fox genes were detected in gonads, with 15 of them at the background expression level (total read per kb per million reads, RPKM < 10), 29 at moderate expression level (10 < total RPKM < 100), and 21 at high expression level (total RPKM > 100). There are 27, 24, 28, and 9 sexually dimorphic fox genes at 5, 30, 90, and 180 days after hatching (dah), respectively. foxq1a, foxf1, foxr1, and foxr1 were identified as the most differentially expressed genes at each stage. foxl2 was characterized as XX-dominant gene, while foxd5, foxi3, foxn3, foxj1a, foxj3b, and foxo6b were characterized as XY-dominant genes. qPCR and in situ hybridization of foxh1 and foxj1a were performed to confirm the expression profiles and to validate the transcriptome data. Our results suggest that fox genes might play important roles in sex determination and gonadal development in teleosts.

Foxo1 regulates Dbh expression and the activity of the sympathetic nervous system in vivo

The transcription factor FoxO1 regulates multiple physiological processes. Here, we show that FoxO1 is highly expressed in neurons of the locus coeruleus and of various sympathetic ganglions, but not in the adrenal medulla. Consistent with this pattern of expression, mice lacking FoxO1 only in sympathetic neurons (FoxO1 Dbh-/-) display a low sympathetic tone without modification of the catecholamine content in the adrenal medulla. As a result, FoxO1 Dbh-/- mice demonstrate an increased insulin secretion, improved glucose tolerance, low energy expenditure, and high bone mass. FoxO1 favors catecholamine synthesis because it is a potent regulator of the expression of Dbh that encodes the initial and rate-limiting enzyme in the synthesis of these neurotransmitters. By identifying FoxO1 as a transcriptional regulator of the sympathetic tone, these results advance our understanding of the control of some aspects of metabolism and of bone mass accrual.

Day/night changes of thymus-deriving natural regulatory T cell development and function

Activity of the immune system shows day/night rhythmicity. Changes in the migration and biological activities of immune cells are strongly regulated by the HPA axis. Another mechanism governing the level of the immune response is based on the suppressive activity of natural regulatory T cells CD4+CD25+Foxp3+ (nTregs) which play a crucial role in the maintenance of self-tolerance and immune homeostasis. The aim of our study was to answer the question: are nTregs changing their development and suppressive activity according to day/night cycle? We demonstrated the effect of day time on nTreg distribution in the thymus and their suppressive potential to inhibit the proliferation of activated responder T cells.

Cutaneous and oral squamous cell carcinoma-dual immunosuppression via recruitment of FOXP3+ regulatory T cells and endogenous tumour FOXP3 expression?

Regulatory T cells (Tregs) are an essential component of the immune system, but are also involved in the suppression of anti-tumour immune responses. The study examines their immunoregulatory role including their transcription factor, FOXP3, in oral and cutaneous SCC. Tregs were detected by double-immunohistochemistry. FOXP3-mRNA-expression was examined in tumour tissue, as well as in skin-derived primary cells and cell lines of different malignancy. Tregs were found in the tumour microenvironment, and FOXP3-mRNA-expression was significantly higher than in normal skin. Intriguingly, single FOXP3(+) cells exhibited morphologic characteristics of SCC cells. Consistent with this, endogenous FOXP3-mRNA-expression was indeed detected in the epidermal cell lineage and dramatically increased with increasing malignancy of the cells. SCCs recruit Tregs into their microenvironment, presumably in order to suppress immunosurveillance, thus avoiding destruction by the immune system. Endogenous FOXP3-expression in malignant epidermoid cells might present a novel mechanism of immune escape.

Decreased expression of FOXJ1 is a potential prognostic predictor for progression and poor survival of gastric cancer

BACKGROUND

FOXJ1 is a member of the forkhead transcription factor family, which has been mostly studied for its role in the development of ciliated epithelium and immunology. However, the role of FOXJ1 in tumorigenesis remains largely unknown or even conflicting. We thus investigated FOXJ1 expression in gastric cancer and analyzed its correlations with tumor progression and prognosis.

METHODS

The expression of FOXJ1 was detected by immunohistochemistry in 105 gastric cancer samples and adjacent noncancerous tissues. Staining evaluation was conducted to assess clinicopathological parameters and the survival rate. In addition, the relation between FOXJ1 and metastasis was investigated in another 40 pairs of primary lesions and corresponding lymph node metastases. Furthermore, cell proliferation, migration, and invasion were confirmed in vitro.

RESULTS

Decreased FOXJ1 expression was significantly correlated with clinic stage, lymph node metastasis, and distant metastasis, and lower FOXJ1 expression independently predicted shorter survival time in gastric carcinoma. Moreover, the positive incidence of FOXJ1 decreased significantly in metastatic lymph nodes compared with that in the primary lesions. Consistently, FOXJ1 overexpression significantly weakened cell proliferation, motility, migration, and invasion, while FOXJ1 knockdown induced the opposite effects.

CONCLUSIONS

Decreased expression of FOXJ1 is an independent prognostic predictor for gastric cancer and is critical to disease progression. FOXJ1 may be an attractive therapeutic target for the treatment of gastric cancer.

FOXP3 transcription factor: a candidate marker for susceptibility and prognosis in triple negative breast cancer

Triple negative breast cancer (TNBC) is a relevant subgroup of neoplasia which presents negative phenotype of estrogen and progesterone receptors and has no overexpression of the human epidermal growth factor 2 (HER2). FOXP3 (forkhead transcription factor 3) is a marker of regulatory T cells (Tregs), whose expression may be increased in tumor cells. This study aimed to investigate a polymorphism (rs3761548) and the protein expression of FOXP3 for a possible involvement in TNBC susceptibility and prognosis. Genetic polymorphism was evaluated in 50 patients and in 115 controls by allele-specific PCR (polymerase chain reaction). Protein expression was evaluated in 38 patients by immunohistochemistry. It was observed a positive association for homozygous AA (OR = 3.78; 95% CI = 1.02–14.06) in relation to TNBC susceptibility. Most of the patients (83%) showed a strong staining for FOXP3 protein in the tumor cells. In relation to FOXP3-positive infiltrate, 47% and 58% of patients had a moderate or intense intratumoral and peritumoral mononuclear infiltrate cells, respectively. Tumor size was positively correlated to intratumoral FOXP3-positive infiltrate (P = 0.026). In conclusion, since FOXP3 was positively associated with TNBC susceptibility and prognosis, it seems to be a promising candidate for further investigation in larger TNBC samples.

Cerebrospinal fluid T-regulatory cells recognize Borrelia burgdorferi NAPA in chronic Lyme borreliosis

The NapA protein of B. burgdorferi is essential for the persistence of spirochetes in ticks. One of the most intriguing aspects of NapA is its potential to interfere with the host immune system. Here, we investigated the role of the acquired immune responses induced by NapA in the cerebrospinal fluids (CSF) of patients with chronic Lyme borreliosis. We evaluated the cytokine profile induced in microglia cells and CSF T cells following NapA stimulation. We report here that NapA induced a regulatory T (Treg) response in the CSF of patients with chronic Lyme borreliosis and it is able to expand this suppressive response by promoting the production of TGF-beta and IL-10 by microglia cells. Collectively, these data strongly support a central role of NapA in promoting both Treg response and immune suppression in the CSF of patients with chronic Lyme borreliosis and suggest that NapA and the Treg pathway may represent novel therapeutic targets for the prevention and treatment of the disease.

Expression of B7-H3, a potential factor of tumor immune evasion in combination with the number of regulatory T cells, affects against recurrence-free survival in breast cancer patients

Background

In the tumor microenvironment, factors inhibiting the targeting of cancer cells by activated T cells have recently been noted. B7-H3 belongs to the B7 superfamily of immune regulatory ligands and plays an important role in the adaptive immune response of co-inhibitory/stimulatory factors in regulating T cells. However, the degree to which B7-H3 directly affects tumor immune evasion mechanisms remains unclear, particularly in patients with breast cancer. Regulatory T cells (Tregs) are known as a key player in the inhibition of immune mechanisms. The present study demonstrated that expression of B7-H3 on tumor cells and the number of Tregs in the tumor microenvironment independently affected prognosis in breast cancer patients.

Methods

We immunohistochemically investigated the presence of B7-H3 and forkhead box P3 (Foxp3)-positive Tregs in pathological specimens from 90 patients with breast cancer.

Results

Positive B7-H3 expression was associated with shorter recurrence-free survival (RFS) (p = 0.014). A higher percentage of Foxp3-positive cells also correlated with shorter RFS (p = 0.039). Multivariate analysis showed B7-H3 as an independent factor on RFS. Foxp3 expression in tumor-infiltrating lymphocytes (TILs) correlated significantly with larger tumor size (>2 cm), expression of human epidermal growth factor receptor 2 (HER2), and higher nuclear grade (p = 0.003, p < 0.001, p = 0.001, respectively). No correlation was identified between expression of B7-H3 and the percentage of Foxp3-positive TILs.

Conclusions

B7-H3 and Foxp3 can be regarded as markers of poor prognosis in breast cancer. These expressions were not correlated, suggesting that B7-H3 expression plays an independent role in tumor immune evasion, regardless of Tregs.

Development of Gene Transfer for Induction of Antigen-specific Tolerance

Gene replacement therapies, like organ and cell transplantation are likely to introduce neo-antigens that elicit rejection via humoral and/or effector T cell immune responses. Nonetheless, thanks to an ever growing body of pre-clinical studies it is now well accepted that gene transfer protocols can be specifically designed and optimized for induction of antigen-specific immune tolerance. One approach is to specifically express a gene in a tissue with a tolerogenic microenvironment such as the liver or thymus. Another strategy is to transfer a particular gene into hematopoietic stem cells or immunological precursor cells thus educating the immune system to recognize the therapeutic protein as "self". In addition, expression of the therapeutic protein in pro-tolerogenic antigen presenting cells such as immature dendritic cells and B cells has proven to be promising. All three approaches have successfully prevented unwanted immune responses in pre-clinical studies aimed at the treatment of inherited protein deficiencies, e.g. lysosomal storage disorders and hemophilia, and of type I diabetes and multiple sclerosis. In this review we focus on current gene transfer protocols that induce tolerance, including gene delivery vehicles and target tissues, and discuss successes and obstacles in different disease models.

Post-transcriptional repression of FOXO1 by QKI results in low levels of FOXO1 expression in breast cancer cells

The RNA-binding protein Quaking (QKI) is known to be essential for embryonic development and postnatal myelination. Forkhead box O1 (FOXO1) is a critical tumor suppressor for cell proliferation control. Dysregulation of FOXO1 expression has been observed in a variety of cancers. In the present study, we demonstrated that QKI decreased FOXO1 mRNA expression at the post-transcriptional level. QKI was able to bind the 3'UTR of FOXO1 mRNA directly and decreased its mRNA stability. To determine whether QKI-mediated post-transcriptional repression of FOXO1 indeed plays a role in cancer cells, we first detected both QKI and FOXO1 expression in four breast cancer cell lines. FOXO1 expression was extremely low in these cell lines, whereas QKI expression was relative high. Knockdown of QKI significantly restored FOXO1 expression. ATRA, an inducer of apoptosis or differentiation, dramatically enhanced FOXO1 expression while it repressed QKI expression. Importantly, the ATRA-induced increase in FOXO1 expression was dependent on QKI-mediated post-transcriptional regulation. Consistently, 5-FU, a widely used chemotherapeutic agent, increased FOXO1 expression via inhibition of QKI. In summary, our study provides initial evidence demonstrating that QKI-mediated repression of FOXO1 may be one of the factors contributing to the oncogenesis and progression of breast carcinoma, which suggests that targeting QKI may serve as a novel strategy to sensitize breast cancers to chemotherapy.

Foxp3 promoter polymorphism (rs3761548) in breast cancer progression: a study from India

Breast cancer is the most common female neoplasm that drives the transformation of normal mammary epithelial cells into highly malignant derivatives. Forkhead Box Protein3 (Foxp3), a tumor suppressor/immunomodulatory gene, which controls the function of Treg cells and oncogenes is down regulated in breast cancer. The main aim of the present study is to evaluate the potential influence of Foxp3-3279 C>A polymorphism (rs3761548) and -2383 C>T polymorphism (rs3761549) in 202 breast cancer patients and 130 normal healthy women of Indian origin. The genotypes were determined using ARMS-PCR for rs3761548 and PCR-RFLP method for rs3761549 using specific primers. The results revealed lack of association of these two polymorphisms with breast cancer susceptibility. However, with respect to AA genotype of rs3761548, we found highly significant association with the advanced stage (T3-4) of the tumor (OR = 3.90; 95% confidence interval (CI) = 1.56-9.70; p = 0.03). Stratified data also revealed an association of homozygous mutant genotype with advanced stage of tumor in premenopausal women (OR = 4.56; 95% CI = 1.07-19.38; p = 0.04) with disease duration of <6 months (OR =  .10; 95% CI = 1.80-20.50; p = 0.002) suggestive of modulating effect of rs3761548 in tumor progression. We conclude that Foxp3 rs37161548 has a potential to be a polymorphic marker for tumor progression in premenopausal breast cancer patients in Indian women.

Molecular evidence for a thymus-independent partial T cell development in a FOXN1-/- athymic human fetus

The thymus is the primary organ able to support T cell ontogeny, abrogated in FOXN1(-/-) human athymia. Although evidence indicates that in animal models T lymphocytes may differentiate at extrathymic sites, whether this process is really thymus-independent has still to be clarified. In an athymic FOXN1(-/-) fetus, in which we previously described a total blockage of CD4(+) and partial blockage of CD8(+) cell development, we investigated whether intestine could play a role as extrathymic site of T-lymphopoiesis in humans. We document the presence of few extrathymically developed T lymphocytes and the presence in the intestine of CD3(+) and CD8(+), but not of CD4(+) cells, a few of them exhibiting a CD45RA(+) naïve phenotype. The expression of CD3εεpTα, RAG1 and RAG2 transcripts in the intestine and TCR gene rearrangement was also documented, thus indicating that in humans the partial T cell ontogeny occurring at extrathymic sites is a thymus- and FOXN1-independent process.

Genetic polymorphism in FOXP3 gene: imbalance in regulatory T-cell role and development of human diseases

The FOXP3 gene encodes a transcription factor thought to be important for the development and function of regulatory T cells (Treg cells). These cells are involved in the regulation of T cell activation and therefore are essential for normal immune homeostasis. Signals from microenvironment have a profound influence on the maintenance or progression of diseases. Thus, Tregs have an important marker protein, FOXP3, though it does not necessarily confer a Treg phenotype when expressed. FOXP3 polymorphisms that occur with high frequency in the general populations have been studied in common multifactorial human diseases. Dysfunction of FOXP3 gene product could result in lack of Treg cells and subsequently chronically activated CD4+ T cells which express increased levels of several activation markers and cytokines, resulting in some autoimmune diseases. In contrast, high Treg levels have been reported in peripheral blood, lymph nodes, and tumour specimens from patients with different types of cancer. The present study discusses the polymorphisms located in intron, exon and promoter regions of FOXP3 which have already been investigated by many researchers. FOXP3 has received considerable attention in attempts to understand the molecular aspect of Treg cells. Therefore, in the present study, the relationship between genetic polymorphism of FOXP3 in Treg-cell role and in disease development are reviewed considering the interactive effect of genetic factors.

Searching for the Achilles Heel of FOXP3

FOXP3 is a multifaceted transcription factor with a major role in the control of immune homeostasis mediated by T regulatory cells (Treg). The immunoregulatory function of FOXP3 may hinder the induction of immune responses against cancer and infectious agents, and thus, development of inhibitors of its functions might give new therapeutic opportunities for these diseases. But also, FOXP3 is an important tumor suppressor factor in some types of cancers, and therefore, understanding the structure and function of FOXP3 is crucial to gaining insights into the development of FOXP3-targeted therapeutic strategies. FOXP3 homodimerize and likely form supramolecular complexes which might include hundreds of proteins which constitute the FOXP3 interactome. Many of the functions of FOXP3 are clearly regulated by the interactions with these cofactors contributing importantly on the establishment of Treg-cell signature. We summarize here the structural/functional information on this FOXP3 complex, to identify potential opportunities for the development of new strategies to modulate FOXP3 activity.

Up-regulation of microRNA-210 induces immune dysfunction via targeting FOXP3 in CD4(+) T cells of psoriasis vulgaris

Psoriasis vulgaris (PV) is a chronic inflammatory and T cell-mediated autoimmune skin disease. An immune dysfunction that is manifested by abnormally activated T cells and defective regulatory T (Treg) cells may play an important role in the pathogenesis of PV. However, the precise mechanism of the immune dysfunction in PV patients still remains unclear. In this study, we found that miR-210 expression is increased significantly in CD4(+) T cells from patients with PV and confirmed that FOXP3 is a target gene of miR-210. We also found that overexpression of miR-210 inhibits FOXP3 expression and impairs the immunosuppressive functions of Treg cells in CD4(+) T cells from healthy controls. In contrast, inhibition of miR-210 increases FOXP3 expression and reverses the immune dysfunction in CD4(+) T cells from patients with PV. Our data demonstrates that increased miR-210 induces immune dysfunction via by FOXP3 in CD4(+) T cells from patients with PV.

CCR7 expression and intratumoral FOXP3+ regulatory T cells are correlated with overall survival and lymph node metastasis in gastric cancer

The aim of this study was to investigate the prognostic value of chemokine receptor CCR7 expression and intratumoral FOXP3⁺ regulatory T cells (Tregs) in gastric cancer. CCR7⁺ tumor cells and FOXP3⁺ Tregs were assessed by immunohistochemistry in tissue microarrays containing gastric cancer from 133 patients. Prognostic effects of low or high CCR7 and FOXP3 expression were evaluated by Cox regression and Kaplan-Meier analysis, as well as the correlation between CCR7 positive score and intratumoral FOXP3⁺ cell number in a longitudinal assessment. The analysis showed that the high expression levels of CCR7 and FOXP3 were detected in 69.9% and 65.4% of cases, respectively. High CCR7 expression in gastric cancer cells was significantly associated with poor overall survival (OS) (P = 0.010) and lymph node metastasis (P = 0.009), and was an independent factor for worse OS (P = 0.023) by multivariate analysis. High numbers of intratumoral FOXP3⁺ Tregs significantly correlated with shorter OS (P = 0.021) and lymph node metastasis (P = 0.024), and was also an independent factor for adverse OS (P = 0.035). Furthermore, there was a significantly positive correlation between CCR7 positive score and intratumoral FOXP3⁺ cell number (r = 0.949, P<0.001). These results revealed that CCR7 expression in gastric cancer cells and intratumoral FOXP3⁺ Tregs could be considered as a co-indicator of clinical prognosis of gastric cancer.

An unbiased in vivo screen reveals multiple transcription factors that control HPV E6-regulated hTERT in keratinocytes

Activation of telomerase by human papillomavirus 16 (HPV16) E6 is a critical step for cell immortalization and transformation in human foreskin keratinocytes (HFKs). Multiple transcription factors have been identified as being involved in E6-induced hTERT expression. Here, we adapted an unbiased in vivo screen using a LacO-LacI system in human cells to discover hTERT promoter-interacting regulators. This approach allowed us to identify a novel hTERT repressor, Maz, which bound the hTERT promoter. E6 expression reduced Maz binding and correspondingly increased Sp1 binding at the hTERT promoter. Knockdown of Maz further increased histone acetylation, as well as hTERT expression in the presence of E6. Overall, these data indicate the utility of a novel screen for promoter-interacting and transcription-regulating proteins. These data also highlight multiple factors that normally regulate hTERT repression in HFKs, and therefore are targeted by E6 for hTERT expression.

Forkhead box protein 3 in human nasal polyp regulatory T cells is regulated by the protein suppressor of cytokine signaling 3

BACKGROUND

In patients with persistent upper airway inflammation, the number of forkhead box protein 3 (Foxp3)(+) regulatory T (Treg) cells is reduced, but the regulation of Foxp3 expression in Treg cells is poorly understood.

OBJECTIVE

We investigated the interaction between suppressor of cytokine signaling 3 (SOCS3) and Foxp3 expression in the airway mucosa.

METHODS

Expression of SOCS3 and Foxp3 was measured in tissue from patients with chronic rhinosinusitis with nasal polyps (CRSwNP) and control tissue. Coexpression of SOCS3 and Foxp3 was evaluated in PBMCs and in tissue from patients with CRSwNP. We also switched off and overexpressed SOCS3 in tissue from patients with CRSwNP and in pancreatic carcinoma epithelial-like cell line (PANC-1) cells and examined the effect on Foxp3 expression.

RESULTS

SOCS3 gene and protein expression was upregulated in inflammatory cells in airway mucosa, whereas Foxp3 gene and protein expression was downregulated. Mucosal Treg cells coexpressed both proteins. Switching off the expression of SOCS3 in human airway mucosa resulted in Foxp3 upregulation, whereas inducing it in PANC-1 cells led to Foxp3 downregulation. We also found that phosphorylation of signal transducer and activator of transcription (STAT) 3 was decreased in inflamed mucosa, and we hypothesized that SOCS3 was responsible. Phosphorylation of STAT3 increased on silencing SOCS3 expression in inflamed mucosa and decreased on SOCS3 plasmid transfection in PANC-1 cells.

CONCLUSION

For the first time, we demonstrate that SOCS3 and Foxp3 are coexpressed in Treg cells in human nasal mucosa and that SOCS3 negatively regulates Foxp3 expression in human airway mucosa, possibly through phosphorylation of STAT3. Hence SOCS3 could be a potential target for restoring Foxp3 expression in Treg cells in patients with persistent mucosal inflammation.

Forkhead Box P family members at the crossroad between tolerance and immunity: a balancing act

Maintaining an immune balance between a chronic inflammatory state and autoimmunity is regulated at multiple levels by complex cellular signaling mechanisms. Numerous immune stimulatory and inhibitory signals converge on a large variety of transcriptional regulators. One key transcriptional regulator of immune homeostasis is FOXP3, which is a member of the Forkhead Box P subfamily of transcription factors and was shown to be essential for the development and maintenance of regulatory T cells. However, other FOXP members have received less attention in relation to a role in immune regulation. Still, recent developments point toward a general important regulatory role for FOXP proteins in the development and function of the adaptive immune system and establishment of a balanced immune response. Here, we discuss the current knowledge on the role of FOXP proteins in establishing immune homeostasis with an emphasis on T-cell biology. Furthermore, we review and speculate about different modes of regulating general FOXP activity and the function of this in health and disease.

FOXN1: A Master Regulator Gene of Thymic Epithelial Development Program

T cell ontogeny is a sophisticated process, which takes place within the thymus through a series of well-defined discrete stages. The process requires a proper lympho-stromal interaction. In particular, cortical and medullary thymic epithelial cells (cTECs, mTECs) drive T cell differentiation, education, and selection processes, while the thymocyte-dependent signals allow thymic epithelial cells (TECs) to maturate and provide an appropriate thymic microenvironment. Alterations in genes implicated in thymus organogenesis, including Tbx1, Pax1, Pax3, Pax9, Hoxa3, Eya1, and Six1, affect this well-orchestrated process, leading to disruption of thymic architecture. Of note, in both human and mice, the primordial TECs are yet unable to fully support T cell development and only after the transcriptional activation of the Forkhead-box n1 (FOXN1) gene in the thymic epithelium this essential function is acquired. FOXN1 is a master regulator in the TEC lineage specification in that it down-stream promotes transcription of genes, which, in turn, regulate TECs differentiation. In particular, FOXN1 mainly regulates TEC patterning in the fetal stage and TEC homeostasis in the post-natal thymus. An inborn null mutation in FOXN1 leads to Nude/severe combined immunodeficiency (SCID) phenotype in mouse, rat, and humans. In Foxn1^−/− nude animals, initial formation of the primordial organ is arrested and the primordium is not colonized by hematopoietic precursors, causing a severe primary T cell immunodeficiency. In humans, the Nude/SCID phenotype is characterized by congenital alopecia of the scalp, eyebrows, and eyelashes, nail dystrophy, and a severe T cell immunodeficiency, inherited as an autosomal recessive disorder. Aim of this review is to summarize all the scientific information so far available to better characterize the pivotal role of the master regulator FOXN1 transcription factor in the TEC lineage specifications and functionality.

The role of FOXP3 in the development and metastatic spread of breast cancer

The transcription factor FOXP3 is widely known for its role in the development and function of immunoregulatory T cells. However, it has been discovered recently that FOXP3 is also expressed in epithelial cells of the normal human breast, ovary and prostate. Aggressive cancer of these epithelial tissues often correlates with abnormal expression of FOXP3, which can be either absent or underexpressed at transcript or protein levels. It is becoming clear that this failure of normal FOXP3 expression can result in dysregulation of the expression of a range of oncogenes which have been implicated in the development and metastasis of cancer. Recent evidence suggests that FOXP3 might also regulate chemokine receptor expression, providing a possible explanation for the chemokine-driven, tissue-specific spread that is characteristic of many cancers. This review first summarises the general structure, function and properties of FOXP3. This is followed by an analysis of the tumour-suppressive properties of this transcription factor, with particular reference to the development and chemokine-mediated spread of human breast cancer. A final section focuses on potential applications of this new knowledge for therapeutic intervention.

FOXP3 expression in tumor cells and tumor-infiltrating lymphocytes is associated with breast cancer prognosis

The forkhead box protein 3 (FOXP3) transcription factor is highly expressed in tumor cells as well as in regulatory T cells (Tregs). It plays a tumor-enhancing role in Tregs and suppresses carcinogenesis as a potent repressor of several oncogenes. The clinical prognostic value of FOXP3 expression has not yet been elucidated. In this study, immunohistochemistry was used to investigate the prognostic significance of FOXP3 expression in tumor cells and tumor-infiltrating lymphocytes (TILs) in breast cancer patients. Of the 100 tumor specimens obtained from primary invasive breast carcinoma, 63 and 57% were evaluated as FOXP3⁺ tumor cells and as being highly infiltrated by FOXP3⁺ lymphocytes, respectively. Although FOXP3 expression in tumor cells was of no prognostic significance, FOXP3⁺ lymphocytes were significantly associated with poor overall survival (OS) (n=98, log-rank test P=0.008). FOXP3 exhibited a heterogeneous subcellular localization in tumor cells (cytoplasm, 31%; nucleus, 26%; both, 6%) and, although cytoplasmic FOXP3 was associated with poor OS (P= 0.058), nuclear FOXP3 demonstrated a significant association with improved OS (P=0.016). Furthermore, when patients were grouped according to their expression of tumor cytoplasmic FOXP3 and lymphocyte FOXP3, there were notable differences in the Kaplan-Meier curves for OS (P<0.001), with a high infiltration of FOXP3⁺ lymphocytes accompanied by a cytoplasmic FOXP3⁺ tumor being the most detrimental phenotype. These findings indicated that FOXP3 expression in lymphocytes as well as in tumor cells may be a prognostic marker for breast cancer. FOXP3 in tumor cells may have distinct biological activities and prognostic values according to its localization, which may help establish appropriate cancer treatments.

Cytotoxic T lymphocyte antigen 4-immunoglobulin G is a potent adjuvant for experimental allergen immunotherapy

Allergen-specific immunotherapy (SIT) is the only treatment for allergic diseases that targets allergen-specific T helper type 2 (Th2) cells, which are the cause of the disease. There is an unmet requirement for adjuvants that increase the clinical efficacy of SIT allowing application of lower doses of the allergen, thereby reducing the risk of anaphylactic reactions. Cytotoxic T lymphocyte antigen 4-immunoglobulin (CTLA-4-Ig) has been shown to induce immunological tolerance in autoimmunity and allograft transplantation by blocking T cell co-stimulation and induction of the immunoregulatory enzyme indoleamine 2,3 dioxygenase (IDO). Previously, we showed that CTLA-4-Ig treatment at the time of allergen inhalation induced tolerance to subsequent allergen exposure in a mouse model of asthma. In this study, we test the hypothesis that CTLA-4-Ig acts as an adjuvant for experimental SIT. We evaluated the adjuvant effects of CTLA-4-Ig on SIT in a mouse model of ovalbumin-driven asthma. We used both wild-type and IDO-deficient mice to assess the role of IDO in the adjuvant effects of CTLA-4-Ig. Co-administration of CTLA-4-Ig strongly increased SIT-induced suppression of airway hyperreactivity (AHR), specific IgE in serum, airway eosinophilia and Th2 cytokine levels. Moreover, we found that CTLA-4-Ig, as an adjuvant for SIT, is equally effective in IDO-deficient and wild-type mice, demonstrating that the effect of CTLA-4-Ig is independent of IDO expression. We show that CTLA-4-Ig acts as a potent adjuvant to augment the therapeutic effects of SIT. As the adjuvant activity of CTLA-4-Ig is independent of IDO, we conclude that it acts by blocking CD28-mediated T cell co-stimulation.

Circulating autoantibody to FOXP3 may be a potential biomarker for esophageal squamous cell carcinoma

The present study was undertaken to develop a relatively quantitative enzyme-linked immunosorbent assay (ELISA) in-house using human leukocyte antigen class II-restricted epitopes in order to test circulating autoantibodies to human forkhead/winged helix transcription factor (FOXP3) as a biomarker for esophageal cancer. A total of 97 patients with esophageal squamous cell carcinoma (ESCC) and 227 healthy subjects were recruited for this study, and their plasma samples were collected for antibody analysis with the ELISA approach. Student's t test showed that the anti-FOXP3 IgG antibody levels were significantly higher in the patient group than the control group (t=6.23, P<0.0001). Based on a cutoff value determined by the mean+3SD of control IgG levels, the positive rate was 5.15 % in patients with ESCC as compared to 0.88 % in control subjects (X (2) =6.53, P=0.019, OR=5.85, 95 % CI 1.12-30.67), in which patients at stage I had the highest positivity (11.54 %, X (2) =12.15, P=0.0005, OR=13.10, 95 % CI 2.09-82.04). The sensitivity against >95 % specificity was 22.7 % for the IgG assay with an inter-assay deviation of 13.35 %. This work suggests that circulating IgG autoantibody to FOXP3 may be a potential biomarker for early diagnosis of esophageal cancer.

Up-regulation of Foxp3 participates in progression of cervical cancer

Foxp3 was identified as a key protein in mediating inhibitory functions of regulatory T cell (Treg). Foxp3 was thought to express only in the T cell lineage until recently when some researches reported that Foxp3 was also expressed by cancer cells. In this study, we describe for the first time the expression of Foxp3 in cervical cancer. Progression from cervical intraepithelial neoplasia (CIN) to cervical cancer is a multistep process initiated by persistent infection with high-risk human papillomavirus (HPV). P16(INK4a) is a crucial marker of HPV integration into host cells. In the present study, expressions of Foxp3 and P16(INK4a) in CIN and cervical cancer were detected by immunohistochemistry. Our results found expression level of Foxp3 was increased during the progression of cervical neoplasia. Moreover, up-regulation of Foxp3 appeared to be correlated with the expression of P16(INK4a). Examination of the role of Foxp3 in differentiation by double immunostaining for cytokeratin 10 (CK10) showed significant association between Foxp3 expression and differentiation (Foxp3 vs CK10). Furthermore, positive expression of Foxp3 was correlated with tumor size. These data suggest that Foxp3 may play an important role in differentiation and growth of cervical cancer cells. Our findings provide new insights regarding the role of Foxp3 in differentiation and its association with HPV infection during the development of cervical cancer.

Murine dendritic cell rapamycin-resistant and rictor-independent mTOR controls IL-10, B7-H1, and regulatory T-cell induction

Mammalian target of rapamycin (mTOR) is an important, yet poorly understood integrative kinase that regulates immune cell function. mTOR functions in 2 independent complexes: mTOR complex (mTORC) 1 and 2. The immunosuppressant rapamycin (RAPA) inhibits mTORC1 but not mTORC2 and causes a paradoxical reduction in anti-inflammatory interleukin (IL) 10 and B7-homolog 1 (B7-H1) expression by dendritic cells (DCs). Using catalytic mTOR inhibitors and DCs lacking mTORC2, we show that restraint of signal transducer and activator of transcription 3-mediated IL-10 and B7-H1 expression during DC maturation involves a RAPA-insensitive and mTORC2-independent mTOR mechanism. Relatedly, catalytic mTOR inhibition promotes B7-H1-dependent and IL-1β-dependent DC induction of regulatory T cells (Tregs). Thus, we define an immunoregulatory pathway in which RAPA-sensitive mTORC1 in DCs promotes effector T-cell expansion and RAPA-insensitive mTORC1 restrains T(reg) induction. These findings identify the first known RAPA-insensitive mTOR pathway that is not mediated solely by mTORC2 and have implications for the use of catalytic mTOR inhibitors in inflammatory disease settings.

Constitutive Akt1 signals attenuate B-cell receptor signaling and proliferation, but enhance B-cell migration and effector function

Ligation of the BCR induces a complex signaling network that involves activation of Akt, a family of serine/threonine protein kinases associated with B-cell development, proliferation, and tumor formation. Here, we analyzed the effect of enhanced Akt1 signals on B-cell maturation and function. Unexpectedly, we found that peripheral B cells overexpressing Akt1 were less responsive to BCR stimuli. This correlated with a decrease in Ca(2+) -mobilization and proliferation, in an impaired activation of Erk1/2 and mammalian target of rapamycin (mTOR) kinases and poor mobilization of NFATc1 and NF-κB/p65 factors. In contrast, activation of STAT5 and migration of B cells toward the chemokine SDF1α was found to be enhanced. Akt1 Tg mice showed an altered maturation of peritoneal and splenic B1 B cells and an enhanced production of IgG1 and IgG3 upon immunization with the T-cell independent Ag TNP-Ficoll. Furthermore, mice homo-zygous for Tg Akt1 showed a severe block in the maturation of B-cell precursors in BM and a strong enrichment of plasma cells in spleen. Altogether, our data reveal that enhanced Akt1 signals modify BCR signaling strength and, thereby, B-cell development and effector function.

Modeling human osteosarcoma in mice through 3AB-OS cancer stem cell xenografts

Osteosarcoma is the second leading cause of cancer-related death for children and young adults. In this study, we have subcutaneously injected-with and without matrigel-athymic mice (Fox1nu/nu) with human osteosarcoma 3AB-OS pluripotent cancer stem cells (CSCs), which we previously isolated from human osteosarcoma MG63 cells. Engrafted 3AB-OS cells were highly tumorigenic and matrigel greatly accelerated both tumor engraftment and growth rate. 3AB-OS CSC xenografts lacked crucial regulators of beta-catenin levels (E-cadherin, APC, and GSK-3beta), and crucial factors to restrain proliferation, resulting therefore in a strong proliferation potential. During the first weeks of engraftment 3AB-OS-derived tumors expressed high levels of pAKT, beta1-integrin and pFAK, nuclear beta-catenin, c-Myc, cyclin D2, along with high levels of hyperphosphorylated-inactive pRb and anti-apoptotic proteins such as Bcl-2 and XIAP, and matrigel increased the expression of proliferative markers. Thereafter 3AB-OS tumor xenografts obtained with matrigel co-injection showed decreased proliferative potential and AKT levels, and undetectable hyperphosphorylated pRb, whereas beta1-integrin and pFAK levels still increased. Engrafted tumor cells also showed multilineage commitment with matrigel particularly favoring the mesenchymal lineage. Concomitantly, many blood vessels and muscle fibers appeared in the tumor mass. Our findings suggest that matrigel might regulate 3AB-OS cell behavior providing adequate cues for transducing proliferation and differentiation signals triggered by pAKT, beta1-integrin, and pFAK and addressed by pRb protein. Our results provide for the first time a mouse model that recapitulates in vivo crucial features of human osteosarcoma CSCs that could be used to test and predict the efficacy in vivo of novel therapeutic treatments.

Recent developments in human immunodeficiency virus-1 latency research

Almost 30 years after its initial discovery, infection with the human immunodeficiency virus-1 (HIV-1) remains incurable and the virus persists due to reservoirs of latently infected CD4(+) memory T-cells and sanctuary sites within the infected individual where drug penetration is poor. Reactivating latent viruses has been a key strategy to completely eliminate the virus from the host, but many difficulties and unanswered questions remain. In this review, the latest developments in HIV-persistence and latency research are presented.

MicroRNA-126 regulates the induction and function of CD4(+) Foxp3(+) regulatory T cells through PI3K/AKT pathway

Recent evidence showed that limited activation of PI3K/Akt pathway was critical for induction and function sustainment of CD4(+) Foxp3(+) regulatory T cells (Tregs). However, the underlying mechanism remains largely unknown. In this study, we reported that miR-126 was expressed in mouse and human Tregs. Further study showed that silencing of miR-126 using miR-126 antisense oligonucleotides (ASO) could significantly reduce the induction of Tregs in vitro. Furthermore, miR-126 silencing could obviously reduce the expression of Foxp3 on Tregs, which was accompanied by decreased expression of CTLA-4 and GITR, as well as IL-10 and TGF-β, and impair its suppressive function. Mechanistic evidence showed that silencing of miR-126 enhanced the expression of its target p85β and subsequently altered the activation of PI3K/Akt pathway, which was ultimately responsible for reduced induction and suppressive function of Tregs. Finally, we further revealed that miR-126 silencing could impair the suppressive function of Tregs in vivo and endow effectively antitumour effect of CD8(+) T cells in adoptive cell transfer assay using a murine breast cancer model. Therefore, our study showed that miR-126 could act as fine-tuner in regulation of PI3K-Akt pathway transduction in the induction and sustained suppressive function of Tregs and provided a novel insight into the development of therapeutic strategies for promoting T-cell immunity by regulating Tregs through targeting specific miRNAs.

Helicobacter pylori induces in-vivo expansion of human regulatory T cells through stimulating interleukin-1β production by dendritic cells

Helicobacter pylori is one of the most common infections in the world. Despite inciting inflammation, immunological clearance of the pathogen is often incomplete. CD4(+) CD25(hi) forkhead box protein 3 (FoxP3(+)) regulatory T cells (T(regs)) are potent suppressors of different types of immune responses and have been implicated in limiting inflammatory responses to H. pylori. Investigating the influence of H. pylori on T(reg) function and proliferation, we found that H. pylori-stimulated dendritic cells (DCs) induced proliferation in T(regs) and impaired their suppressive capability. This effect was mediated by interleukin (IL)-1β produced by H. pylori-stimulated DCs. These data correlated with in-vivo observations in which H. pylori(+) gastric mucosa contained more T(regs) in active cell division than uninfected stomachs. Inciting local proliferation of T(regs) and inhibiting their suppressive function may represent a mechanism for the chronic gastritis and carcinogenesis attributable to H. pylori.

Protection of Tregs, suppression of Th1 and Th17 cells, and amelioration of experimental allergic encephalomyelitis by a physically-modified saline

In multiple sclerosis (MS) and other autoimmune diseases, the autoreactive T cells overcome the resistance provided by the regulatory T cells (Tregs) due to a decrease in the number of Foxp3-expressing Tregs. Therefore, upregulation and/or maintenance of Tregs during an autoimmune insult may have therapeutic efficacy in autoimmune diseases. Although several immunomodulatory drugs and molecules are available, most present significant side effects over long-term use. Here we have undertaken an innovative approach to upregulate Tregs and achieve immunomodulation. RNS60 is a 0.9% saline solution generated by subjecting normal saline to Taylor-Couette-Poiseuille (TCP) flow under elevated oxygen pressure. RNS60, but not NS (normal saline), RNS10.3 (TCP-modified saline without excess oxygen) and PNS60 (saline containing excess oxygen without TCP modification), was found to upregulate Foxp3 and enrich Tregs in MBP-primed T cells. Moreover, RNS60, but not NS, RNS10.3 and PNS60, inhibited the production of nitric oxide (NO) and the expression of iNOS in MBP-primed splenocytes. Incubation of the cells with an NO donor abrogated the RNS60-mediated upregulation of Foxp3. These results suggest that RNS60 boosts Tregs via suppression of NO production. Consistent to the suppressive activity of Tregs towards autoreactive T cells, RNS60, but not NS, RNS10.3, or PNS60, suppressed the differentiation of Th17 and Th1 cells and shifted the balance towards a Th2 response. Finally, RNS60 treatment exhibited immunomodulation and ameliorated adoptive transfer of experimental allergic encephalomyelitis, an animal model of MS, via Tregs. These results describe a novel immunomodulatory property of RNS60 and suggest its exploration for therapeutic intervention in MS and other autoimmune disorders.