Understanding the Role of the Unfolded Protein Response Sensor IRE1 in the Biology of Antigen Presenting Cells

The unfolded protein response (UPR) is an adaptive response that maintains the fidelity of the cellular proteome in conditions that subvert the folding capacity of the cell, such as those noticed in infection and inflammatory contexts. In immunity, the UPR sensor IRE1 (Inositol-requiring enzyme 1-alpha) has emerged as a critical regulator of the homeostasis of antigen presenting cells (APCs). In the past few years, it has become clear that IRE1 plays canonical and non-canonical roles in APCs, many of which intersect with key features of these cells, including the initiation of inflammation, antibody production, and antigen presentation. The aims of the present review are to provide recent insights on the mechanisms by which IRE1 regulates the diversity of APC functions and to highlight its relevance in the coordination of innate and adaptive immunity

Students’ perceptions of oral corrective feedback given by teachers in communicative approach english courses from an efl pedagogy program at a private university

El propósito de esta investigación fue definir e identificar la percepción de los estudiantes sobre la retroalimentación correctiva oral dada por los profesores en los cursos de inglés de la carrera de Pedagogía en Inglés en una universidad privada de Santiago de Chile. Esta investigación fue desarrollada acorde a un diseño mixto con un enfoque cualitativo, con el fin de lograr una selección precisa de los datos y del enfoque del problema. La recolección de datos requirió la aplicación de dos instrumentos, un cuestionario y un grupo de discusión. El cuestionario se aplicó a 68 estudiantes de segundo a cuarto año. Mientras que el grupo de discusión se aplicó a 9 estudiantes de segundo a cuarto año. Los resultados demuestran claramente las percepciones positivas acerca de la retroalimentación recibida de parte de los profesores durante los cursos de inglés, de esta manera beneficiando su proceso de aprendizaje y mejorando sus habilidades lingüísticas.The main aim of this research was to define and identify the students’ perception of oral corrective feedback given by teachers in Communicative Approach English courses from an EFL teaching program at a private university from Santiago, Chile. This research was developed according to a mixed design with qualitative approach in order to achieve an accurate selection of the data and scope of the problem. The data collection required the implementation of two instruments, a questionnaire and a focus group. The questionnaire was applied to 68 diurnal students from second year to fourth year. Meanwhile, the focus group was applied to nine diurnal students from second year to fourth year. The results that were obtained in relation to the topics and the corresponding theoretical analysis clearly demonstrate positive perceptions regarding the feedback received from teachers during English language courses, thus, benefitting their learning process and improving language skills

Vitamin A Impairs the Reprogramming of Tregs into IL-17-Producing Cells during Intestinal Inflammation

Maintaining the identity of Foxp3+ regulatory T cells (Tregs) is critical for controlling immune responses in the gut, where an imbalance between Tregs and T effector cells has been linked to inflammatory bowel disease. Accumulating evidence suggests that Tregs can convert into Th17 cells and acquire an inflammatory phenotype. In this study, we used an adoptive transfer model of Ag-specific T cells to study the contribution of different factors to the reprogramming of in vitro-generated Treg cells (iTreg) into IL-17-producing cells in a mouse model of gut inflammation in vivo. Our results show that intestinal inflammation induces the reprogramming of iTreg cells into IL-17-producing cells and that vitamin A restrains reprogramming in the gut. We also demonstrate that the presence of IL-2 during the in vitro generation of iTreg cells confers resistance to Th17 conversion but that IL-2 and retinoic acid (RA) cooperate to maintain Foxp3 expression following stimulation under Th17-polarizing conditions. Additionally, although IL-2 and RA differentially regulate the expression of different Treg cell suppressive markers, Treg cells generated under different polarizing conditions present similar suppressive capacity

In Vitro-Generated Tc17 Cells Present a Memory Phenotype and Serve As a Reservoir of Tc1 Cells In Vivo

Memory CD8+ T cells are ideal candidates for cancer immunotherapy because they can mediate long-term protection against tumors. However, the therapeutic potential of different in vitro-generated CD8+ T cell effector subsets to persist and become memory cells has not been fully characterized. Type 1 CD8+ T (Tc1) cells produce interferon-γ and are endowed with high cytotoxic capacity, whereas IL-17-producing CD8+ T (Tc17) cells are less cytotoxic but display enhanced self-renewal capacity. We sought to evaluate the functional properties of in vitro-generated Tc17 cells and elucidate their potential to become long lasting memory cells. Our results show that in vitro-generated Tc17 cells display a greater in vivo persistence and expansion in response to secondary antigen stimulation compared to Tc1 cells. When transferred into recipient mice, Tc17 cells persist in secondary lymphoid organs, present a recirculation behavior consistent with central memory T cells, and can shift to a Tc1 phenotype. Accordingly, Tc17 cells are endowed with a higher mitochondrial spare respiratory capacity than Tc1 cells and express higher levels of memory-related molecules than Tc1 cells. Together, these results demonstrate that in vitro-generated Tc17 cells acquire a central memory program and provide a lasting reservoir of Tc1 cells in vivo, thus supporting the use of Tc17 lymphocytes in the design of novel and more effective therapies

Purinergic Signaling as a Regulator of Th17 Cell Plasticity

T helper type 17 (Th17) lymphocytes, characterized by the production of interleukin-17 and other pro-inflammatory cytokines, are present in intestinal lamina propria and have been described as important players driving intestinal inflammation. Recent evidence, supporting the notion of a functional and phenotypic instability of Th17 cells, has shown that Th17 differentiate into type 1 regulatory (Tr1) T cells during the resolution of intestinal inflammation. Moreover, it has been suggested that the expression of CD39 ectonucleotidase endows Th17 cells with immunosuppressive properties. However, the exact role of CD39 ectonucleotidase in Th17 cells has not been studied in the context of intestinal inflammation. Here we show that Th17 cells expressing CD39 ectonucleotidase can hydrolyze ATP and survive to ATP-induced cell death. Moreover, in vitro-generated Th17 cells expressing the CD39 ectonucleotidase produce IL-10 and are less pathogenic than CD39 negative Th17 cells in a model of experimental colitis in Rag-/- mice. Remarkably, we show that CD39 activity regulates the conversion of Th17 cells to IL-10-producing cells in vitro, which is abrogated in the presence of ATP and the CD39-specific inhibitor ARL67156. All these data suggest that CD39 expression by Th17 cells allows the depletion of ATP and is crucial for IL-10 production and survival during the resolution of intestinal inflammation

Th17_TGF-β1 cells present a regulatory phenotype.

<p>(A) IL-17-GFP+ Th17_TGF-β1 and Th17_IL-23 cells were sorted and then analyzed by real-time PCR for mRNA expression of several transcription factors and cytokines (n = 3). (B) IL-17-GFP+ Th17_TGF-β1 and Th17_IL-23 cells were sorted and then reactivated for 4 hrs with PMA plus ionomycin to assess cytokine production by CBA or (C) in the presence of PMA, ionomycin and brefeldin A to analyze GM-CSF production by FACS (n = 5). (D) Percentage of GM-CSF+ cells within IL-17-GFP+ Th17_TGF-β1 and Th17_IL-23 cells (n = 5). Data are presented as mean ± S.E.M. *p<0.05, **p<0.01 and ***p<0.001 determined by t-test (A) or Mann-Whitney test (B and D).</p

ATP hydrolysis by CD39 on Th17_TGF-β1 cells promotes their conversion into IL-10-producing cells.

<p>(A) IL-10 production by IL-17-GFP+ Th17_TGF-β1 and Th17_IL-23 cells restimulated for 3 days with anti-CD3 and anti-CD28 antibodies in the presence and absence of Tr1 polarizing cytokines (TGF-β1, IL-21 and IL-27), 50 μM ATP and 250 μM ARL67156. IL-10 production was analyzed by CBA (n = 4). (B) Th17_IL-23 cells from wild-type and P2X7R knockout mice were restimulated for 3 days with anti-CD3 and anti-CD28 antibodies and IL-10 production was analyzed by CBA (n = 3). Data are presented as mean ± S.E.M. *p<0.05; **p<0.01 determined by repeated measures analysis of variance.</p

Th17_TGF-β1 but not Th17_IL-23 cells hydrolyze ATP to adenosine in a CD39-and CD73-dependent manner and survive in the presence of high doses of ATP.

<p>IL-17-GFP+ Th17_TGF-β1 and Th17_IL-23 cells were sorted and cultured for 1 hr with 10 μM ATP in the presence of 50 μM ARL67156 or 50 μM APCP. Supernatants were then analyzed by HPLC to assess (A and B) ATP and (C and D) AMP hydrolysis (n = 5). (E) Representative FACS analysis of Th17 cell survival (Annexin V-/PI-) in the presence of graded doses of ATP. (F) Percentage of Th17 cell survival in the presence of ATP (n = 3). (G) IL-17-GFP+ Th17_TGF-β1 and Th17_IL-23 cells were sorted and then analyzed by real-time PCR to assess mRNA encoding P2X7 receptor (n = 4). Data are presented as mean ± S.E.M. *p<0.05 and **p<0.01 determined by Mann-Whitney test (B and D), two-way analysis of variance (F) or t-test (G).</p

Th17_TGF-β1 cells are less colitogenic than Th17_IL-23 cells and produce IL-10 and IFN-γ <i>in vivo</i>.

<p>1.3x10⁶ IL-17-GFP+ Th17_TGF-β1 and Th17_IL-23 cells were transferred to Rag1^-/- mice. (A) The weight of mice was measured over the course of 6 weeks after adoptive transfer of Th17 cells (n = 5–8 mice per group). (B) Colon length was measured 6 weeks following transfer of Th17 cells (n = 5). (C) Clinical score was calculated based on weight loss and colon length 6 weeks after adoptive transfer of Th17 cells (n = 5). (D) Colonic histopathology. H&E and alcian blue staining, original magnification 20X. Scale bar 100 μm (E) To determine intestinal cytokine production, intestinal tissues of Th17 recipient mice were cultured for 24 hs at 37°C and 5% CO₂ and production of several cytokines was analyzed by CBA (n = 6). (F and G) Representative FACS analysis of IL-17, IL-10 and IFN-γ production by Th17_TGF-β1 and Th17_IL-23 cells 6 weeks after adoptive transfer to Rag1^-/- mice. Data are presented as mean ± S.E.M. *p<0,05, **p<0,01 and ***p<0,001 comparing Th17_TGF-β1 and Th17_IL-23; ᵜᵜp<0,01 comparing PBS and Th17_TGF-β1; ^¤¤¤p<0,001 comparing PBS and Th17_IL-23 determined by two-way analysis of variance (A). *p<0,05 determined by Kruskal-Wallis test (B,C and E).</p