Stress-Induced Despair Behavior Develops Independently of the AHR-RORgt Axis in CD4+ cells

Current treatments for major depressive disorder are limited to neuropharmacological approaches and are ineffective for large numbers of patients. Recently, alternative means have been explored to understand the etiology of depression. Specifically, changes in the microbiome and immune system have been observed in both clinical settings and in mouse models. As such, microbial supplements and probiotics have become a target for potential therapeutics. A current hypothesis for the mechanism of action of these supplements is via the aryl hydrocarbon receptor’s (AHR) modulation of the T helper 17 cell (Th17) and T regulatory cell axis. As inflammatory RORgt+ CD4+ Th17 T cells and their primary cytokine IL-17 have been implicated in the development of stress-induced depression, the connection between stress, the AHR, Th17s and depression remains critical to disease understanding. Here, we utilize genetic knockouts to examine the role of the microbial sensor AHR in the development of stress induced despair behavior. We observe an AHR-independent increase in gut-associated Th17s in stressed mice, indicating that AHR is not responsible for this communication. Further, we utilized a CD4-specific Rorc knockout line to disrupt the production of Th17s. Mice lacking Rorc induced IL-17 did not show any differences in behavior from controls before or after stress. Finally, we utilize an unsupervised machine learning system to examine minute differences in behavior that could not be observed in traditional behavioral assays. Our data demonstrate that neither CD4 specific Ahr nor Rorc are necessary for the development of stress-induced anxiety-or depressive-like behaviors. These data suggest that research approaches should focus on other sources or sites of IL-17 production in stress-induced depression.

Identification of Germline Monoallelic Mutations in IKZF2 in Patients with Immune Dysregulation

Helios, encoded by IKZF2, is a member of the Ikaros family of transcription factors with pivotal roles in T-follicular helper, NK- and T-regulatory cell physiology. Somatic IKZF2 mutations are frequently found in lymphoid malignancies. Although germline mutations in IKZF1 and IKZF3, encoding Ikaros and Aiolos, have recently been identified in patients with phenotypically similar immunodeficiency syndromes, the effect of germline mutations in IKZF2 on human hematopoiesis and immunity remains enigmatic. We identified germline IKZF2 mutations (one nonsense (p.R291X)- and 4 distinct missense variants) in six patients with systemic lupus erythematosus, immune thrombocytopenia or EBV-associated hemophagocytic lymphohistiocytosis. Patients exhibited hypogammaglobulinemia, decreased number of T-follicular helper and NK-cells. Single-cell RNA sequencing of PBMCs from the patient carrying the R291X variant revealed upregulation of pro-inflammatory genes associated with T-cell receptor activation and T-cell exhaustion. Functional assays revealed the inability of HeliosR291X to homodimerize and bind target DNA as dimers. Moreover, proteomic analysis by proximity-dependent Biotin Identification revealed aberrant interaction of 3/5 Helios mutants with core components of the NuRD complex conveying HELIOS-mediated epigenetic and transcriptional dysregulation.

Effects of Salmonella enterica ser. Enteritidis and Heidelberg on host CD4+CD25+ regulatory T cell suppressive immune responses in chickens

Poultry infected with Salmonella mount an immune response initially, however the immune responses eventually disappear leading the bird to be a carrier of Salmonella. The hypothesis of this study is that Salmonella infection induces T regulatory cell numbers and cytokine production and suppress host T cells locally in the gut to escape the host immune responses. An experiment was conducted to comparatively analyze the effect of S. enterica ser. Enteritidis (S. Enteritidis) and S. enterica ser. Heidelberg (S. Heidelberg) infection on CD4+CD25+ T regulatory cell properties in chickens. A total of 144 broiler chicks were randomly distributed into three experimental groups of non-infected control, S. Enteritidis infected and S. Heidelberg infected groups. Chickens were orally inoculated with PBS (control) or 5x106 CFU/mL of either S. Enteritidis or S. Heidelberg at 3 d of age. Each group was replicated in six pens with eight chickens per pen. Chickens infected with S. Enteritidis had 6.2, 5.4, and 3.8 log10 CFU/g, and chickens infected with S. Heidelberg had 7.1, 4.8, and 4.1 log10 CFU/g Salmonella in the cecal contents at 4, 11, and 32 dpi, respectively. Both S. Enteritidis and S. Heidelberg were recovered from the liver and spleen 4 dpi. At 4, 11, and 32 dpi, chickens infected with S. Enteritidis and S. Heidelberg had increased CD4+CD25+ cell numbers as well as IL-10 mRNA transcription of CD4+CD25+ cells compared to that in the control group. CD4+CD25+ cells from S. Enteritidis- and S. Heidelberg-infected chickens and restimulated with 1 μg antigen in vitro, had higher (P < 0.05) IL-10 mRNA transcription than the CD4+CD25+ cells from the non-infected controls Though at 4dpi, chickens infected with S. Enteritidis and S. Heidelberg had a significant (P < 0.05) increase in CD4+CD25- IL-2, IL-1β, and IFNγ mRNA transcription, the CD4+CD25- IL-2, IL-1β, and IFNγ mRNA transcription, were comparable to that in the control group at 11 and 32dpi identifying that the host inflammatory response against Salmonella disappears at 11 dpi. It can be concluded that S. Enteritidis and S. Heidelberg infection at 3 d of age induces a persistent infection through inducing CD4+CD25+ cells and altering the IL-10 mRNA transcription of CD4+CD25+ cell numbers and cytokine production in chickens between 3 to 32 dpi allowing chickens to become asymptomatic carriers of Salmonella after 18 dpi.

Immune Dysregulation in Patients With Chromosome 18q Deletions—Searching for Putative Loci for Autoimmunity and Immunodeficiency

IntroductionAutoimmune disorders, IgA deficiency, and allergies seem to be common among individuals with 18q deletion syndrome [OMIM 601808]. We aimed to determine the prevalence, mechanism, and genetic background of autoimmunity, immune deficiency, and allergy in a cohort of patients with 18q deletions.Material and MethodsMedical registries and social media were used to recruit the patients. Microarray oligonucleotide comparative genomic hybridization (aCGH) (Agilent, Santa Clara, CA, USA) was performed in all patients to identify size and location of chromosome 18 deletion. Clinical evaluation and medical record collection were performed in each of the study participants. The history of autoimmune disorders, severe and/or recurrent infections, and symptoms of allergy were noted. Total immunoglobulin IgG, IgA, IgM, IgE, and IgG1-4 serum levels were measured using nephelometry and ELISA methods. Lymphocyte T subset phenotyping was performed in 24 subjects from 18q del cohort. To predict the most promising candidate genes, we used the ENDEAVOUR—a free web resource for gene prioritization.Results18q deletion was confirmed by means of array CGH analysis in 27 individuals, 15 (55.6%) females and 12 males, referred to the project by specialists in medical genetics, diabetology, or pediatric endocrinology between May 2015 and December 2019. The mean age at examination was 11.8 years (min–max: 4.0–33.5). Autoimmune disorders were present in 14/27 (51.8%) of the cohort. In eight of patients, symptoms of immune deficiency coexisted with autoimmunity. Allergy was reported in nine of 27 (33.4%) patients. Over 89% of patients presented with at list one type of immunoglobulin (IgA, IgM, IgG, IgE, and IgG1-4) deficiency and eight of 25 (32%) had abnormalities in at least two major immunoglobulin (IgG, IgA, IgM) measurements (CVID-like phenotype). Patients with 18q del exhibited a significantly decreased CD4, Treg FOXP3+, TregFOXP3+Helios+, and TemCD4 cell numbers in comparison with the control groups of 24 T1DM patients and 28 healthy controls.ConclusionsPatients with 18q deletions frequently suffer from autoimmune disorders, recurrent infections, and allergy due to immune dysregulation presenting with variable antibody deficiencies and T-regulatory cell deficiency (CD4+CD25+CD127lowFOXP3+). The spectrum of speculations regarding which gene might be responsible for such phenotype ranges from single gene haploinsufficiency to deletion of a cluster of immunogenes located distally to 18q21.

Defining CD4 T helper and T regulatory cell endotypes of progressive and remitting pulmonary sarcoidosis (BRITE): protocol for a US-based, multicentre, longitudinal observational bronchoscopy study

IntroductionSarcoidosis is a multiorgan granulomatous disorder thought to be triggered and influenced by gene–environment interactions. Sarcoidosis affects 45–300/100 000 individuals in the USA and has an increasing mortality rate. The greatest gap in knowledge about sarcoidosis pathobiology is a lack of understanding about the underlying immunological mechanisms driving progressive pulmonary disease. The objective of this study is to define the lung-specific and blood-specific longitudinal changes in the adaptive immune response and their relationship to progressive and non-progressive pulmonary outcomes in patients with recently diagnosed sarcoidosis.Methods and analysisThe BRonchoscopy at Initial sarcoidosis diagnosis Targeting longitudinal Endpoints study is a US-based, NIH-sponsored longitudinal blood and bronchoscopy study. Enrolment will occur over four centres with a target sample size of 80 eligible participants within 18 months of tissue diagnosis. Participants will undergo six study visits over 18 months. In addition to serial measurement of lung function, symptom surveys and chest X-rays, participants will undergo collection of blood and two bronchoscopies with bronchoalveolar lavage separated by 6 months. Freshly processed samples will be stained and flow-sorted for isolation of CD4 +T helper (Th1, Th17.0 and Th17.1) and T regulatory cell immune populations, followed by next-generation RNA sequencing. We will construct bioinformatic tools using this gene expression to define sarcoidosis endotypes that associate with progressive and non-progressive pulmonary disease outcomes and validate the tools using an independent cohort.Ethics and disseminationThe study protocol has been approved by the Institutional Review Boards at National Jewish Hospital (IRB# HS-3118), University of Iowa (IRB# 201801750), Johns Hopkins University (IRB# 00149513) and University of California, San Francisco (IRB# 17-23432). All participants will be required to provide written informed consent. Findings will be disseminated via journal publications, scientific conferences, patient advocacy group online content and social media platforms.

Harnessing CD8+CD28− Regulatory T Cells as a Tool to Treat Autoimmune Disease

T regulatory cell therapy presents a novel therapeutic strategy for patients with autoimmune diseases or who are undergoing transplantation. At present, the CD4+ Treg population has been extensively characterized, as a result of defined phenotypic and functional readouts. In this review article, we discuss the development and biology of CD8+ Tregs and their role in murine and human disease indications. A subset of CD8+ Tregs that lack the surface expression of CD28 (CD8+CD28− Treg) has proved efficacious in preclinical models. CD8+CD28− Tregs are present in healthy individuals, but their impaired functionality in disease renders them less effective in mediating immunosuppression. We primarily focus on harnessing CD8+ Treg cell therapy in the clinic to support current treatment for patients with autoimmune or inflammatory conditions.

Toll-Like Receptor 2 Promotes Breast Cancer Progression and Resistance to Chemotherapy

Background. Breast cancer (BC) is the leading cause of cancer death in women, due to the development of resistance to current therapies, including chemotherapy. Since breast cancer stem cells (CSCs) are the main drivers of therapy resistance and disease progression, chemoresistance might be prevented targeting the molecules that promote their self-renewal. We previously demonstrated that Toll-like Receptor (TLR)2 is overexpressed in CSCs, which exploit it to promote their self-renewal through an autocrine loop initiated by high mobility group box (HMGB)1. TLR2 expression in BC is associated with poor prognosis in patients, suggesting that it could be a good target for BC therapies.Methods. We generated and characterized TLR2WT and TLR2KO autochthonous mammary cancer mouse models. In-vitro and in-vivo studies were performed to assess the efficacy of TLR2 silencing and inhibition in combination with chemotherapy.Results. TLR2KO mice displayed delayed tumor onset, increased survival, and reductions in CSC and T regulatory cell frequency, compared to TLR2WT mice. Transplantation experiments using TLR2WT and TLR2KO cells injected subcutaneously into TLR2WT and TLR2KO mice showed that TLR2 mainly acts via cancer-cell-intrinsic mechanisms, such as increased cell survival and CSC self-renewal. Moreover, TLR2 promoted cancer cell resistance to chemotherapy following the doxorubicin-induced release of HMGB1. Thus, TLR2 inhibitors impaired the viability and induced the apoptosis of BC cells and exerted a synergistic effect when administered with chemotherapy both in-vitro and in-vivo. Conclusions. We have demonstrated that TLR2 inhibitors reinstate BC response to chemotherapy, opening new perspectives for the treatment of BC patients.