Malin E. Winerdal

FOXP3 Promoter Demethylation Reveals the Committed Treg Population in Humans

Background Naturally occurring thymus derived regulatory T cells (Tregs) are central in the maintenance of self-tolerance. The transcription factor FOXP3 is crucial for the suppressive activity of Tregs and is considered the most specific marker for this population. However, human non regulatory T cells upregulate FOXP3 transiently upon activation which calls for other means to identify the Treg population. Since epigenetic mechanisms are involved in the establishment of stable gene expression patterns during cell differentiation, we hypothesized that the methylation profile of the FOXP3 promoter would allow the distinction of truly committed Tregs. Methodology/Principal Findings Human CD4+CD25hi Tregs displayed a demethylated FOXP3 promoter (1.4%±0.95% SEM methylated) in contrast to CD4+CD25lo T cells which were partially methylated (27.9%±7.1%). Furthermore, stimulated CD4+CD25lo T cells transiently expressed FOXP3 but remained partially methylated, suggesting promoter methylation as a mechanism for regulation of stable FOXP3 expression and Treg commitment. In addition, transient FOXP3 expressing cells exhibited suppressive abilities that correlate to the methylation status of the FOXP3 promoter. As an alternative to bisulphite sequencing, we present a restriction enzyme based screening method for the identification of committed Tregs and apply this method to evaluate the effect of various culturing conditions. We show that a partial demethylation occurs in long-term cultures after activation, whereas the addition of TGF-β and/or IL-10 does not induce any additional change in methylation level. Conclusions/Significance The unique FOXP3 promoter methylation profile in Tregs suggests that a demethylated pattern is a prerequisite for stable FOXP3 expression and suppressive phenotype. Presently, FOXP3 is used to identify Tregs in several human diseases and there are future implications for adoptive Treg transfer in immunotherapy. In these settings there is a need to distinguish true Tregs from transiently FOXP3+ activated T cells. The screening method we present allows this distinction and enables the identification of cells suitable for in vitro expansions and clinical use.

FOXP3 and survival in urinary bladder cancer

Whats known on the subject? and What does the study add?

At the crossroads of T helper lineage commitment-Epigenetics points the way.

The immune system has the capacity to respond to various types of pathogens including bacteria, viruses, tumors and parasites. This requires a flexible immune system, which in part depends on the development of alternative effector T helper cells, with different cytokine repertoires that direct the overall immune response. The reciprocal effects of the T helper subtypes Th1 and Th2 are well documented, but the mechanisms involved in alternative cytokine expression and silencing are less well defined. Introduction of advances within the field of chromatin folding and epigenetic regulation of transcription has begun to explain some of the fundamental principles of T helper cell development. In addition, epigenetic regulation has proven essential also for the more recently discovered T helper cell subtypes; regulatory T cells and the Th17 lineage. As the importance of proper epigenetic regulation becomes evident, attention is also focused on the potential harmfulness of epigenetic dysregulation. Autoimmunity and allergy are two clinical situations that have been implicated as results of imperfect cytokine silencing. This review will address recent advances in the field of epigenetic regulation of T lymphocytes and their maturation from naive cells into different effector T cell lineages. In particular, epigenetic involvement in regulation of key effector cytokines and specific transcription factors determining the CD4(+) T lymphocyte lineage commitment will be discussed.

Long Lasting Local and Systemic Inflammation after Cerebral Hypoxic ischemia in Newborn Mice

Background Hypoxic ischemia (HI) is an important cause of neonatal brain injury and subsequent inflammation affects neurological outcome. In this study we performed investigations of systemic and local activation states of inflammatory cells from innate and adaptive immunity at different time points after neonatal HI brain injury in mice. Methodology/Principal Findings We developed a multiplex flow cytometry based method combined with immunohistochemistry to investigate cellular immune responses in the brain 24 h to 7 months after HI brain injury. In addition, functional studies of ex vivo splenocytes after cerebral hypoxic ischemia were performed. Both central and peripheral activation of CD11b+ and CD11c+ antigen presenting cells were seen with expression of the costimulatory molecule CD86 and MHC-II, indicating active antigen presentation in the damaged hemisphere and in the spleen. After one week, naïve CD45rb+ T-lymphocytes were demonstrated in the damaged brain hemisphere. In a second phase after three months, pronounced activation of CD45rb− T-lymphocytes expressing CD69 and CD25 was seen in the damaged hemisphere. Brain homogenate induced proliferation in splenocytes after HI but not in controls. Conclusions/Significance Our findings demonstrate activation of both local and systemic immune responses months after hypoxic ischemic neonatal brain injury. The long term immune activation observed is of general importance for future studies of the inflammatory response after brain injury as most previous studies have focused on the first few weeks after damage, while the effects of the late inflammation phase may be missed. Furthermore, the self-reactive component raises the question if there is a correlation with development of autoimmune brain disease later in life.

Genetic Abrogation of Adenosine A3 Receptor Prevents Uninephrectomy and High Salt–Induced Hypertension

Background Early‐life reduction in nephron number (uninephrectomy [UNX]) and chronic high salt (HS) intake increase the risk of hypertension and chronic kidney disease. Adenosine signaling via its different receptors has been implicated in modulating renal, cardiovascular, and metabolic functions as well as inflammatory processes; however, the specific role of the A3 receptor in cardiovascular diseases is not clear. In this study, gene‐modified mice were used to investigate the hypothesis that lack of A3 signaling prevents the development of hypertension and attenuates renal and cardiovascular injuries following UNX in combination with HS (UNX‐HS) in mice. Methods and Results Wild‐type (A3 +/+) mice subjected to UNX‐HS developed hypertension compared with controls (mean arterial pressure 106±3 versus 82±3 mm Hg; P<0.05) and displayed an impaired metabolic phenotype (eg, increased adiposity, reduced glucose tolerance, hyperinsulinemia). These changes were associated with both cardiac hypertrophy and fibrosis together with renal injuries and proteinuria. All of these pathological hallmarks were significantly attenuated in the A3 −/− mice. Mechanistically, absence of A3 receptors protected from UNX‐HS–associated increase in renal NADPH oxidase activity and Nox2 expression. In addition, circulating cytokines including interleukins 1β, 6, 12, and 10 were increased in A3 +/+ following UNX‐HS, but these cytokines were already elevated in naïve A3 −/− mice and did not change following UNX‐HS. Conclusions Reduction in nephron number combined with chronic HS intake is associated with oxidative stress, chronic inflammation, and development of hypertension in mice. Absence of adenosine A3 receptor signaling was strongly protective in this novel mouse model of renal and cardiovascular disease.

LPS Regulates SOCS2 Transcription in a Type I Interferon Dependent Autocrine-Paracrine Loop

Recent studies suggest that SOCS2 is involved in the regulation of TLR signaling. In this study, we found that the expression of SOCS2 is regulated in human monocyte-derived DC by ligands stimulating TLR2, 3, 4, 5, 8 and 9 signaling. SOCS2 induction by LPS was dependent on the type I IFN regulated transcription factors IRF1 and IRF3 as shown by using silencing RNAs for IRFs. Blocking endogenous type I IFN signaling, by neutralizing antibodies to the receptor IFNAR2, abolished SOCS2 mRNA expression after TLR4 stimulation. Transcription factors STAT3, 5 and 6 displayed putative binding sites in the promoter regions of the human SOCS2 gene. Subsequent silencing experiments further supported that STAT3 and STAT5 are involved in LPS induced SOCS2 regulation. In mice we show that SOCS2 mRNA induction is 45% lower in bone marrow derived macrophages derived from MyD88−/− mice, and do not increase in BMMs from IRF3−/− mice after BCG infection. In conclusion, our results suggest that TLR4 signaling indirectly increases SOCS2 in late phase mainly via the production of endogenous type I IFN, and that subsequent IFN receptor signaling activates SOCS2 via STAT3 and STAT5.

Doxorubicin enhances the capacity of B cells to activate T cells in urothelial urinary bladder cancer

Cancer is currently treated by a combination of therapies, including chemotherapy which is believed to suppress the immune system. Combination of immunotherapy and chemotherapy correlates with improved survival but needs careful planning in order to achieve a synergistic effect. In this study, we have demonstrated that doxorubicin treatment of B cells resulted in increased expression of CD86 and concordantly increased CD4+ T cell activation in the presence of superantigen, an effect that was inhibited by the addition of a CD86 blocking antibody. Furthermore, doxorubicin resulted in decreased expression of the anti-inflammatory cytokines IL-10 and TNF-α. Finally, B cells from urinary bladder cancer patients, treated with a neoadjuvant regiment containing doxorubicin, displayed increased CD86-expression. We conclude that doxorubicin induces CD86 expression on B cells and hence enhances their antigen-presenting ability in vitro, a finding verified in patients. Development of tailored time and dose schedules may increase the effectiveness of combining chemotherapy and immunotherapy.

Single Dose Caffeine Protects the Neonatal Mouse Brain against Hypoxia Ischemia

In this randomized blinded study, we investigated caffeine 5 mg/kg treatment given directly after neonatal brain hypoxia ischemia. Brain morphology, behavior and key brain infiltrating immune populations were examined. Caffeine treatment significantly improves outcome when compared to phosphate buffered saline. Flow cytometric analysis of immune responses revealed no persistent immunological alterations. Given its safety caffeine emerges as a candidate for neuroprotective intervention after neonatal brain injury.

Urothelial bladder cancer may suppress perforin expression in CD8+ T cells by an ICAM-1/TGFβ2 mediated pathway

The immune system plays a significant role in urothelial bladder cancer (UBC) progression, with CD8+ T cells being capable to directly kill tumor cells using perforin and granzymes. However, tumors avoid immune recognition by escape mechanisms. In this study, we aim to demonstrate tumor immune escape mechanisms that suppress CD8+ T cells cytotoxicity. 42 patients diagnosed with UBC were recruited. CD8+ T cells from peripheral blood (PB), sentinel nodes (SN), and tumor were analyzed in steady state and in vitro-stimulated conditions by flow cytometry, RT-qPCR, and ELISA. Mass spectrometry (MS) was used for identification of proteins from UBC cell line culture supernatants. Perforin was surprisingly found to be low in CD8+ T cells from SN, marked by 1.8-fold decrease of PRF1 expression, with maintained expression of granzyme B. The majority of perforin-deficient CD8+ T cells are effector memory T (TEM) cells with exhausted Tc2 cell phenotype, judged by the presence of PD-1 and GATA-3. Consequently, perforin-deficient CD8+ T cells from SN are low in T-bet expression. Supernatant from muscle invasive UBC induces perforin deficiency, a mechanism identified by MS where ICAM-1 and TGFβ2 signaling were causatively validated to decrease perforin expression in vitro. Thus, we demonstrate a novel tumor escape suppressing perforin expression in CD8+ T cells mediated by ICAM-1 and TGFβ2, which can be targeted in combination for cancer immunotherapy.

Neoadjuvant Chemotherapy Reinforces Antitumour T cell Response in Urothelial Urinary Bladder Cancer

Evidence indicates that neoadjuvant chemotherapy (NAC) may promote antitumour immune responses by activating T cells. The tumour-draining sentinel node (SN) is a key site to study tumour-specific T cell activation, being the primary immunological barrier against the tumour. In this prospective study, we set out to elucidate the effects of NAC on T cell subsets in the SNs of patients with muscle-invasive urothelial bladder cancer. We found that CD8+ effector T (Teff) cell exhaustion was reduced after NAC treatment, while cytotoxicity was increased. Additionally, in complete responders (CR patients), these cells were functionally committed effectors, as displayed by epigenetic analysis. In CD4+ Teffs, NAC treatment was associated with increased clonal expansion of tumour-specific SN-derived cells, as demonstrated by a specific cell reactivity assay. In contrast, we observed an attenuating effect of NAC on regulatory T cells (Tregs) with a dose-dependent decrease in Treg frequency and reduced effector molecule expression in the remaining Tregs. In addition, multicolour flow cytometry analysis revealed that CR patients had higher Teff to activated Treg ratio, promoting antitumoural T cell activation. These results suggest that NAC reinforces the antitumour immune response by activating the effector arm of the T cell compartment and diminishing the influence of suppressive Tregs. PATIENT SUMMARY: In this report, we analysed the effect of chemotherapy on immune cell subsets of 40 patients with advanced bladder cancer. We found that chemotherapy has a positive effect on immune effector T cells, whereas an opposite, diminishing effect was observed for immune-suppressive regulatory T cells. We conclude that chemotherapy reinforces the antitumour immune response in bladder cancer patients.