bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of ERK2 in dendritic cell function
Authors: Abdul-Baki Nawal Samer , Jeffreys Sean , Negron Austin Joseph , Forsthuber Thomas G
Published: January 2023

Dendritic cells (DCs) are an important link between the innate and adaptive immune systems, specifically by serving as key regulators of T cell-dependent (TD) immune responses. In DCs, several processes critical for initiating TD immune responses, such as migration, provision of costimulatory signals, and antigen uptake and presentation, utilize the mitogen-activated protein kinase (MAPK) signaling pathway. The dysregulation of these processes can result in the aberrant activation of autoreactive CD4+ T cells, resulting in autoimmune disease. Extracellular signal-regulated kinase 1 and 2 (ERK1/2) are key effectors of the MAPK pathway, and while ERK1 has been shown to be a critical regulator of DC migration and TLR-induced IL-10 secretion, the function of ERK2 remains unknown. Our lab has developed a novel mouse model in which the inducible Cre-mediated deletion of Erk2 is accompanied by the expression of an eYFP reporter protein. This provides us the unique ability to circumvent the embryonic lethality of deleting Erk2 in the germline while also allowing the detection of viable Erk2-deficient cells via flow cytometry. Preliminary data using this model has shown that Erk2Δ bone marrow-derived DCs (BMDCs), as well as Erk2Δ splenic DCs, exhibit altered expression of surface markers associated with T cell costimulation, antigen presentation, and migration compared with DCs from littermate controls. Taken together, this suggests that ERK2 plays a unique role in the regulation of several DC functions, potentially opening a new approach to treating CD4+ T cell-mediated autoimmune diseases.
Dissecting the molecular mechanisms underpinning T cell help for Dendritic Cell
Authors: Gressier Elise Marie , Whitney Paul , Schmidt Susanne , Bedoui Sammy
Published: January 2023

CD8+ T cell priming relies on the ability of dendritic cells (DCs) to present antigen as well as to communicate contextual cues associated with antigen acquisition. Efficient CD8+ T cell response often requires DC interactions with helper CD4+ T cells through CD40-CD40L binding. Previously, our work showed that CD4+ T cell help amplifies the capacity of DCs to generate efficient priming of CD8+ T cell in response to suboptimal innate stimuli. Focusing on the CD40-driven amplification of innate pathways induced in IFN-α/β-stimulated DCs, this study explores the dynamics and molecular mechanisms underpinning such help phenotype. We have observed that the CD40-mediated amplification of IFN-α responses follows precise kinetics and affects only a portion of the innate stimulus-induced genes such as Il-15, Ccl5 or Tnf-α. Interestingly, a group of genes, unresponsive to IFN-α alone, required the combination of both stimuli to trigger their expression. These results highlighted the induction of two distinct patterns of gene regulation in response to CD40 and IFN-α stimulations, the amplified and the combinatorial. Based on transcriptomics, proteomics and phosphoproteomics data sets analyses, our data mining suggests the cooperation between IRFs and NF-κB transcription factors, acting in synergy towards the enhancement of DC responses and governing which genes can be amplified. Furthermore, the gene regulation and post-transcriptional modification of proteins involved in the regulation of NF-κB indicate a tight control of this signaling pathway. By dissecting how T cell help amplifies innate signals required for CD8+ T cell priming, this work will assist in the development of more targeted T-cell-based therapeutic strategies.
PRMT5 controls pathogenicity and metabolic genes during Th17 polarization
Authors: Piedra-Quintero Zayda L. , Sengupta Shouvonik , Webb Lindsay M , Amici Stephanie A , Laliotis Georgios , Tsichlis Philip N , Guerau-de-Arellano Mireia
Published: January 2023

PRMT5 catalyzes symmetric dimethylation (SDM) on arginine residues. PRMT5 methylates histone H3 and H4 producing remodeling of chromatin and regulation of gene transcription. PRMT5 is induced after T cell activation. Furthermore, both PRMT5 inhibitors and PRMT5 knockdown impair T cell proliferation and activation. However, the role of PRMT5 in T cell differentiation has not been analyzed. T cells undergo metabolic reprograming during activation which is critical for polarization. Differentiating T cells increase bioenergetics and anabolic pathways enhancing glycolysis, catabolism, uptake of fatty acids and oxidative phosphorylation. Whether PRMT5 has an impact on Th17 differentiation and metabolic reprograming is unknown. To address this question, we performed Th17 differentiation and RNA sequencing analyses in T cells from PRMT5fl/fl and iCD4-PRMT5Δ/Δ mice. Th17 differentiation was sharply suppressed in PRMT5 KO T cells, in which 25–30% of genes in the glycolysis, lactate or TCA pathways were reduced. To evaluate the functional effects of PRMT5 on energy metabolism, extracellular acidification rate (ECAR) and Oxygen consumption rate (OCR) were analyzed in Jurkat T cells transduced with control or PRMT5 shRNA and lactate secretion was measured on supernatants of Th1 and Th17 cells from PRMT5fl/fl and iCD4-PRMT5Δ/Δ mice. Knock down of PRMT5 decreased ECAR in Jurkat cells and lactate production in Th1 and Th17 cells in absence of PRMT5. In conclusion, PRMT5 promotes glycolytic energy metabolism and Th17 differentiation in T cells.
Dynamic changes in patterns of ganglioside expression characterize maturation of lymphoid lineage cells into effector cells and suggest a close relationship between CD8+ T cells and NK cells
Authors: Johnson Taylor , Knapp Mary-Peyton A. , Ritter Madison K. , King-Lyons Natalie D. , Grier Jennifer T. , Rainer Robert O , Connell Terry D. , Arce Sergio
Published: January 2023

Gangliosides are glycosphingolipids that play important regulatory roles in cell signaling and differentiation. To investigate their expression patterns during lymphoid cell development, human PBMC were stained with recombinant B subunits of LT-IIa, LT-IIb, or LT-IIc and with select mAb. FACS analysis showed that ganglioside ligands for LT-IIaB, LT-IIbB, and LT-IIcB were increasingly expressed during transition from naïve to memory to effector memory CD4+ T cells, with ganglioside ligands for LT-IIbB exhibiting the greatest increase. A similar trend was observed in CD8+ T cell subsets, except no major changes in the expression of LT-IIaB ligands were detected. Patterns of ganglioside expression in NK cell subsets were remarkably similar to those observed in the CD8+ T cells: The ganglioside ligands for LT-IIbB and LT-IIcB were increasingly expressed during transition from tissue-resident to effector to differentiated/exhausted NK cells, with ganglioside ligands for LT-IIbB exhibiting the greatest increase and ligands for LT-IIaB showing little change across subsets. Finally, expression of LT-IIaB- and LT-IIcB-binding gangliosides increased during transition from naïve to memory to antibody-secreting B cells, with ganglioside ligands for LT-IIaB exhibiting the greatest increase and ligands for LT-IIbB showing little change across subsets. Our results demonstrated the existence of dynamic changes in the patterns of gangliosides expressed throughout lymphoid cell development and differentiation. The distinct patterns suggest the existence of cell signaling differences between and within the distinct lymphoid cell lineages and a close developmental and functional relationship between CD8+ T cells and NK cells.
Substrate rigidity affects human regulatory T cell induction in vitro
Authors: Shi Lingting , Kam Lance
Published: January 2023

Immunotherapy using regulatory T cells (Tregs) has shown recent successes in the treatment of autoimmune diseases. While natural Tregs are unstable and dysfunctional in the inflammatory milieu, induced Tregs are more potent and durable. Tregs can be induced from CD4+CD25− T cells in vitro with TGF-β and IL-2 during activation. Chemical pathways in Treg induction have been heavily investigated, but the impact of mechanical cues has not been thoroughly explored. As T cell activation has been shown to be sensitive to the substrate rigidity, Treg induction may also be mechanosensitive. To test this hypothesis, Tregs were induced on polyacrylamide gels of different rigidities (Young’s modulus of 5 to 110 kPa) coated with anti-CD3 and anti-CD28 for 72 hrs. The stiffer substrate significantly increased Treg induction, measured by percent FoxP3 high T cells. To further understand this process, single cell RNA-Seq analysis was performed on cells induced on 5 and 110 kPa gels, which revealed three clusters including conventional CD4+ cells, transition cells, and Tregs. For 5 kPa substrates, a higher proportion of cells expressed the FOXP3 genes than detected protein, whereas the proportions of cells that express the FOXP3 gene and protein were consistent on the 110 kPa gels. FOXP3+ cells on the softer gel also showed upregulation of genes that encode for ribosomal proteins and proteasomes. Thus, there could be some mechanism inhibiting expression or promoting degradation of FoxP3 protein in 5 kPa. Lastly, the induced Tregs in two groups exhibited different cell cycle profiles. These results indicated the mechanosensitive nature of Treg induction, which can assist in the biomaterial design for generating Tregs to advance Treg adoptive therapy.
SUMO-specific protease 2 restrains the differentiation of Th17 cells
Authors: Yang Tsan-Tzu , Shih Hsiu-Ming , Lin Kuo-I
Published: January 2023

Accumulating evidence suggests that posttranslational modifications (PTMs) play a critical role in the regulation of cellular functions and disease progression. Several reports indicated that SUMOylation, a type of PTMs, contributes to diseases through modulation of cell signaling and functions. The process of SUMOylation is dynamic and can be reversibly removed by the sentrin-specific protease (SENP) family. Smad4 has been shown to suppress the differentiation of pathogenic Th17 cells and can be deSUMOylated by SENP2. Here, we would like to study whether SUMOylation may affect T cell development and differentiation, and T cell-mediated diseases.

To study the roles of Senp2 in T cell lineage, we generated Senp2f/f×Lck-cre (CKO) mice. We found that there were more Th1 and Th17 cells in CKO mice in the steady state, as compared with those in littermate controls (wild type, WT) mice. Besides, Senp2-deficiency in T cells also promotes the progression of dextran sodium sulfate (DSS)-induced colitis in mice. The levels of IFNg and IL-17 produced by in vitro differentiated Th1 and Th17 cells, respectively, were higher when Senp2 is deleted. The enzymatic activity of Senp2 is required for the inhibition of Th17 differentiation; as compared with the effects of lentiviral vector expressing wild type Senp2, transduction of differentiating CKO Th17 cells with a lentiviral vector expressing a catalytic domain mutant Senp2 failed to suppress the frequency of Th17 cells. We are examining if SUMOylation affects the function of Smad4 in Th17 cells. Results from this study may provide insights into the new therapeutic strategy for the control of Th17-mediated diseases.
Foreign epitope-specific regulatory T cells respond robustly to vaccination and limit Th1 differentiation by conventional T cells specific for the same epitope
Authors: Krueger Peter D , Jenkins Marc K
Published: January 2023

CD4+ naïve T cell populations specific for MHCII-bound foreign peptides contain FOXP3− conventional (Tconv) cells and less abundant FOXP3+ regulatory (Treg) cells. Little is known about how naïve Treg cells respond to foreign peptides and for what purpose given that their activation might impede immunity. We addressed this issue by tracking naïve T cells after vaccination with a foreign peptide in an oil-based adjuvant. The Tconv and Treg naïve cells specific for the peptide proliferated extensively during the first week after vaccination. The Tconv population generated only Tconv progeny, mainly of the T helper 1 (Th1) and follicular helper (Tfh) varieties. Most of the naïve Treg cells formed Th1- or T helper 17 (Th17)-like Treg progeny while a minority lost FOXP3 and adopted a Tfh phenotype. The Treg progeny limited the formation of conventional Th1 cells in peptide-specific manner. Thus, foreign peptide-specific naïve Treg cells undergo a robust primary response that generates progeny resembling Th1 and Th17 cells that limit differentiation of their conventional Th1 counterparts.
IFN-γ signaling is essential for the clearance of C. neoformans in the brain and survival of the infected mice
Authors: Chen Yanli , Strickland Ashley , Shi Meiqing
Published: January 2023

Cryptococcus neoformans is an encapsulated pathogenic fungus, which primarily infects immunocompromised individuals including HIV-infected patients, organ transplant recipients, and patients treated with immunosuppressive drugs. Each year, about 180,000 people die from cryptococcosis. Although it is believed that C. neoformans enters the body through the airway and initially causes infections in the lung, cryptococcosis commonly presents as meningoencephalitis. Previous studies mainly focused on immune responses to C. neoformans in the lung, and little is known about mechanisms involved in the clearance of the organism in the brain. IFN-γ signaling has been previously shown to play a critical role in control of the fungal infections in the lung. In the current study, we characterize the role of IFN-γ signaling in the clearance of C. neoformans in the brain using a mouse model of brain infections. The results show that IFN-γR−/− mice died significantly earlier compared to wild-type mice following intravenous infection with C. neoformans. Infected IFN-γR−/− mice displayed significantly higher fungal burden in the brain with enlarged lesion size compared to infected wild-type mice. The impaired clearance of C. neoformans in the brain of IFN-γR−/− mice was associated with reduced production of proinflammatory cytokines in the brain, altered recruitments of leukocytes to the brain, and M2-type polarization of microglia. We conclude that IFN-γ signaling is essential for the clearance of C. neoformans in the brain and survival of the infected mice.
Glucuronoxylomannan in the Cryptococcus species capsule as a target for CAR+ T-cell therapy
Authors: Kumaresan Pappanaicken , daSilva Thiago , Laskowski Tamara
Published: January 2023

The genus Cryptococcus comprises two major fungal species that cause clinical infections in humans: C. gattii and C. neoformans. Each year, about 1 million cases of Cryptococcus infection are reported worldwide, and the infection’s mortality rate ranges from 20% to 70%. To combat the cryptococcosis, we proposed the redirection of CD8+ T cells to target glucuronoxylomannan (GXM), a sugar present in the Cryptococcus species capsule, via expression of a GXM-specific chimeric antigen receptor (GXMR-CAR) for treatment of cryptococcosis. GXMR-CAR has an anti-GXM single-chain variable fragment followed by an IgG4 stalk, a CD28 transmembrane domain, and CD3-zeta and CD28 signaling domains. After lentiviral transduction of human T cells with the GXMR-CAR construct, flow cytometry demonstrated that 82.4% of the cells expressed GXMR-CAR on their surface. To determine whether the GXMR-CAR+ T cells exhibited GXM-specific recognition, these cells were incubated with GXM for 24 h and examined using bright-field microscopy. Large clusters of proliferating GXMR-CAR+ T cells were observed, while no clusters were present in the control cells. The ability of GXMR-CAR T cells to bind to the yeast form of C. neoformans was detected by flow cytometry and fluorescent microscopy, but no binding was detected in mock-transduced control T cell (NoDNA T cells). Furthermore, when GXMR-CAR+ T cells were administered to immunocompromised NSG mice infected with C. neoformans their C. neoformans burden was significantly lower than mock-transduced control T cell treated mice as shown via immunofluorescence using an anti-GXM antibody and Gomori methenamine-silver (GMS) staining of Titan cells in lung tissue.
Correlation of DNA Methylation Status and Immune Function in the Cytotoxic Immune Cells of Tuberculosis Patients
Authors: Nishiguchi Tomoki , Mtetwa Godwin , Kay Alexander , Maphalala Gugu , Mandalakas Anna , Coarfa Cristian , DiNardo Andrew
Published: January 2023

BACKGROUND

Less than 10% of individuals infected with Mtb develop disease. Similarly, in the pre-antibiotic era, ~20% of Tuberculosis (TB) patients overcame the disease. This implies host immunity can control Mtb infection. We evaluated the role of cytotoxic immune cells (CD8, CD56 and CD3+CD56+) among individuals with chronic infections that increase risk of TB progression.

METHODS

DNA Methyl EPIC was evaluated in patients with helminths, HIV and TB (n = 32) and flow-based immune phenotyping was implemented on 108 individuals. Gene expression of 717 TB patients and 525 healthy controls was downloaded from publicly available databases.

RESULTS

All evaluated cytotoxic cells displayed DNA methylation perturbations in the IL-2-STAT5, PI3K and IFNγ signaling pathways. TB patients experienced DNA hyper-methylation of perforin in CD56 NK cells and in granzyme A and granzyme B of CD8+ cytotoxic lymphocytes (CTLs). By flow cytometry TB patients up-regulated mycobacterial-specific perforin in CTLs while CD3−CD56+ NK cells expressed decreased perforin. Early evidence suggests that the increased perforin expression from CTLs was heterogenous and only occurs in ~46% of TB patients. Further evidence for heterogenous TB sub-groups was demonstrated by gene expression as 333 TB patients had increased perforin gene expression, while 313 had decreased gene expression (log2 fold change with FDR < 1%).

CONCLUSION

To evaluate the DNA methylation-immune phenotype associations from this clinical cohort, mechanistic studies manipulating DNA methylation status are undergoing. Identifying how epigenetic modifications alter cytotoxic cells capacity to kill intracellular mycobacteria is critical to future host directed therapeutic options.
Role of meningeal lymphatic vessels in the T cell response against Toxoplasma gondii
Authors: Kovacs Michael , Smirnov Igor , Batista Samantha J. , Cowan Maureen N. , Still Katherine M. , Bolte Ashley C. , Harris Tajie H.
Published: January 2023

Toxoplasma gondii is an intracellular protozoan parasite that causes persistent infection in the central nervous system (CNS). Studies have demonstrated that continuous T cell recruitment to the brain is necessary for parasite control. However, the mechanisms by which T cell responses against T. gondii are maintained remain poorly understood. Recently, it was discovered that the meninges harbor a previously unappreciated lymphatic network that drains CNS protein and immune cells. We hypothesized that the meningeal lymphatic network is necessary for maintaining host-protective T cell responses against T. gondii. To test this hypothesis, we performed surgical ligation of the lymphatic vessels that carry cerebrospinal fluid via meningeal lymphatic vessels to the cervical lymph nodes. Following blockade of meningeal lymphatic outflow, we observed a decrease in the number and frequency of antigen-specific T cells in the deep cervical lymph nodes, supporting a role for meningeal lymphatic drainage in maintaining T cell responses against the parasite. We have also observed extensive lymphangiogenesis in the meninges during infection. Lymphangiogenesis has not previously been reported in response to CNS infection but could influence antigen or immune cell outflow from the CNS. Together, our results demonstrate that the meningeal lymphatic network dynamically responds to CNS infection with T. gondii and contributes to T cell responses against the parasite.
CD4 T cells are important in protection against M. tuberculosis reinfection in cynomolgus macaques
Authors: Ganchua Sharie Keanne C , Maiello Pauline , Hopkins Forrest , Fortune Sarah , Flynn JoAnne L
Published: January 2023

Early human studies show individuals with latent M. tuberculosis (Mtb) infection are less likely to develop active tuberculosis (TB) compared to naïve individuals with similar levels of exposure. Using Mtb-barcoded libraries (Lib A as first and Lib B as second infection), we published that an existing Mtb infection in cynomolgus macaques protects against the establishment and progression of a second Mtb challenge. CD4 T cells are important in control of TB, and depletion results in worse acute infection and latent TB reactivation in macaques. We hypothesized that CD4 T cells play a major role in protection against a secondary Mtb challenge. To test this hypothesis, CD4 T cells were depleted in infected and treated macaques before a second Mtb challenge. As controls, one group received IgG and a naive group received only Lib B. The number of Lib B granulomas in the IgG group was significantly fewer than in the naïve group, while the αCD4 group was in between the two. The IgG group had the lowest lung bacterial burden followed by the αCD4 group (16-fold higher than IgG) and lastly the naïve group (57.5-fold higher than IgG). Both reinfected groups (αCD4 and IgG) had a higher frequency of CD8 T cells producing IFNγ and/or TNF in Lib B granulomas compared to naïve macaques but there was no significant difference when compared to each other. Because each Mtb bacterium has a unique barcode, we can track the spread of Mtb to different organs. Both naïve and αCD4 groups had a greater number of unique Lib B barcodes in the thoracic lymph nodes compared to the IgG group. These data suggest that CD4 T cells help limit the establishment, progression and dissemination of the second infection. However, they are not the only factor responsible for protection against reinfection.
Effect of muscarine and atropine in the synthesis and secretion of IgA by T-dependent and T-independent mechanisms in small intestine of mice
Authors: Albor Aldo Arturo Resendiz , Rebollar-Ruíz Xóchitl Abril , Arciniega-Martínez Ivonne Maciel , Santamaría-Chávez Mónica Miguel , Campos-Rodríguez Rafael
Published: January 2023

IgA secretion is carried out through two pathways: T dependent in which the T cells cooperate in the production of this immunoglobulin and the T independent in which the isotype switch is made by mechanisms independent of CD4 T cells, each one of the pathways is identified by the expression of specific cytokines which are required to be able to switch the isotype. The enteric nervous system through acetylcholine and muscarinic and nicotinic receptors regulates the immune system however the mechanisms by which it does have not been completely elucidated, In this work we evaluated the effect it has muscarine and atropine in the secretion of total IgA and secretory IgA in the small intestine, the production of cytokines was measure in Th2 cells (IL-4, IL-5, IL-10, IL-12 and TGF-β) and the expression of independent T cytokines (APRIL, BAFF and BAFF receptor) in lamina propia (LP) and Peyer’s patches (PP). The results obtained we indicate that muscarine produces an increase in total IgA while atropine lowers it, the cytokines that increased with the agonist treatment were IL-5, IL-12 and TGF-β in PP while cytokines that decreased with the muscarinic antagonist were IL-4 and TGF-β in the LP. Besides the muscarine increased the expression of APRIL and BAFF in the inducer site and the effector site, the BAFF receptor in microvilli increase with muscarine in PP. In this study the muscarinic and nicotinic receptors regulates the secretion of total IgA in the small intestine in BALB/c mice.

This work was supported by SIP and COFFA IPN.
Tbet-expressing Tregs protect against lethal immunopathology during T. gondii infection
Authors: Wohlfert Elizabeth A , Warunek Jordan , Jin Richard M , Marzullo Brandon
Published: January 2023

Toxoplasma gondii infection has proven to be an ideal model to understand the delicate balance between protective immunity and immune mediated pathology. Tregs are necessary for maintaining immune homeostasis, particularly in the gut where immune tolerance to food and the microbiota is tightly regulated. Oral infection with T. gondii leads to a robust Th1 immune response initiating in the GI tract and has also been implicated in dysbiosis associated with inflammatory bowel disease. During T. gondii infection, Tregs highly express the Th1 lineage specifying transcription factor, Tbet, throughout infection. To determine the role of Tbet in Tregs, we infected Tbetf/f-Foxp3YFPCre and control Foxp3YFPCre mice with the type II strain ME49 T. gondii, Surprisingly, greater than 75% Tbetf/f-Foxp3YFPCre mice succumb to infection at peak acute infection while nearly 100% of the control Foxp3YFPCre mice survive. Analysis of parasite burden showed Tbetf/f-Foxp3YFPCre mice controlled the infection. Tbetf/f-Foxp3YFPCre mice did not control the Th1 mediated inflammation, which lead to immune mediated pathology. Depletion of CD4+ T cells and antibiotic treatment ameliorates morbidity in Tbetf/f-Foxp3YFPCre mice. While loss of Tbet in Tregs lead to higher frequencies and numbers of Tregs, these cells were still unable to prevent lethal immunopathology. RNA-seq analysis reveals that Tbet regulates several key cellular pathways and developmental processes that enhance the Treg’s ability to suppress immune response in a Th1 environment. Taken together, our data highlights an essential role for Tbet in Tregs to prevent lethal immunopathology during acute Toxoplasma gondii infection.
Cigarette smoke has opposite effects in murine models of ulcerative colitis and Crohn’s disease through mucosal immunity and gut environment
Authors: Kitabatake Masahiro , Nishioka Tatsuki , Ouji-Sageshima Noriko , Ito Toshihiro
Published: January 2023

Inflammatory bowel diseases (IBD), comprising ulcerative colitis (UC) and Crohn’s disease (CD), represent chronic intestinal inflammation, and the exact cause of each disease is still unclear. Clinical studies have reported that smoking exacerbates pathogenesis in CD patients, whereas it plays a protective factor in UC patients. However, the mechanism of how smoking has different effects on UC and CD remains unknown.

In this study, C57BL/6 mice were exposed with cigarette smoke (CS; 20 cigarettes/day) for two weeks, and then, mice were administered dextran sodium sulfate (DSS) or tri-nitrobenzene sulfonic acid (TNBS) to induce colitis as UC and CD model, respectively. CS exposure improved the colon inflammation and histological score in UC model, while it worsened them in CD model. In UC model, CS induced regulatory T cells (Tregs) and decreased activated CD8+ T cells. Diversity of gut microbiota was expanded by CS exposure. Interestingly, proportion of Lachnospiraceae, which is thought to generate short chain fatty acid and induce Tregs, was increased. On the other hand, Th1 cells were significantly increased in lamina propria in CD model, and diversity of gut microbiota was decreased and proportion of Enterobacteriaceae, which is considered to associate with onset and enhanced inflammation in IBD, was remarkably increased in CD model. Moreover, one of metabolites induced by CS in UC model improved DSS-induced colitis by increasing Tregs and by decreasing inflammatory cytokines in colon.

These results suggest that CS exposure regulates pathogenesis of IBD by changing gut environment including gut microbiota as well as intestinal immunity.
Olfactory sensory neurons regulate mucosal antiviral immune responses
Authors: Kraus Aurora , Salinas Irene
Published: January 2023

The olfactory mucosa is the first line of defense against respiratory and neurotropic viruses but must balance eradication of virus with the cost of extended inflammation that can itself be deleterious. In bony fish, aquatic rhabdovirus and olfactory sensory neurons (OSNs) directly interact prompting action potentials toward the olfactory bulb (OB) and rapid onset of immune gene transcription and cell infiltration. The presence of viral invaders in the olfactory organ (OO) must be dealt with swiftly to protect the central nervous system (CNS), however, the mechanisms by which OSNs participate in defense are unknown. The goal of this project is to understand the role OSN activation plays in regulating ultra- rapid immune responses to rhabdovirus. I have established a zebrafish model of nasal rhabdoviral infection where intranasal viral delivery causes inflammation and vasodilation in the zebrafish OO in just 15 minutes. Both the OO and OB show little neuronal damage by immunofluorescence of apoptosis markers. In both larval and adult fish OSN activation sends signals to the OB, mediating significant behavioral changes. single cell (sc)RNA-Seq of the OB reveals the onset of a protective state where both microglia and neurons downregulate sensory differentiation factors and innate immune response mediators (cytokines/complement), in the absence of viral translocation. Together these experiments reveal that viral detection by OSNs creates a neuroprotective state in both the OO and OB in minutes. Further work aims to elucidate precise mechanisms by which OSNs are participating in immediate antiviral immunity.
A novel lung DC(3) population potently induces Th17 responses to inhaled allergens
Authors: Cook Donald N , Izumi Gentaro , Karmaus Peer WF , Nakano Hideki
Published: January 2023

Allergic asthma is an inflammatory disease of the airways associated with T helper (Th)2-driven eosinophilia and Th17-directed neutrophilia. Although eosinophilic asthma generally responds well to inhaled glucocorticoids, neutrophilic asthma does not, and new therapies are needed for this disease subtype. A consensus DC subset in the lung that strongly promotes Th17 responses to inhaled allergens has remained elusive, as some groups have reported that CD103+ DCs (DC1) promote Th17 differentiation, whereas other groups have attributed this function to CD11bhi DCs (DC2). We hypothesized that this apparent discrepancy might be due to the heterogeneity of lung CD11b+ DCs and therefore used mass cytometry (CyTOF) to study these cells following allergic sensitization through the airway. We identified a novel CD11b+ APC that was recruited to the inflamed airways of mice following their inhalation of house dust extracts. These cells were bona fide DCs, as they were FLT3L-dependent, expressed Zbtb46, and formed dendrites. Bulk RNA-seq analysis of these DCs revealed that their transcriptome was similar to, yet distinct from, that of conventional DC2s. Although the novel DCs promoted only weak Th2 differentiation, they drove robust Th17 differentiation. Single cell RNA-sequencing of total lung CD11bhi DCs revealed seven distinct clusters, two of which co-expressed both Tgfb1 and Il1b. Pseudotime analysis suggested a progression from an immature form of these cells to a more mature form. Together, these findings identify a novel DC population (DC3) in the lung that potently stimulates Th17 responses to inhaled allergens.
Inhibition of Acute Type-2 Lung Inflammation by 2′3′-cyclic Guanosine Monophosphate-Adenosine Monophosphate (2′3′-cGAMP)
Authors: She Li , Barrera Gema , Yan Liping , Alanazi Hamad , Brooks Edward , Dube Peter , Sun Yilun , Liu Yong , Zhang Nu , zhang Xin , Li Xiao-Dong
Published: January 2023

2′3′-cGAMP is known as a novel non-classical 2nd messenger synthesized by the novel DNA sensor cyclic GMP-AMP synthase (cGAS) in response to cytosolic invasion of DNA-containing microorganisms in mammalian cells. 2′3′-cGAMP possess potent anti-tumor, antiviral and immune adjuvant effects via the STING-mediated signaling pathway. However, its function in modulating type-2 immune responses remains unclear. In this report, we investigated the role of 2′3′-cGAMP in regulating type-2 inflammatory reactions in a mouse model of allergic asthma. We demonstrate that 2′3′-cGAMP strongly inhibits both IL-33 and allergen-driven acute type-2 lung inflammation and airway hyperresponsiveness. Mechanistically, we demonstrate that 2′3′-cGAMP treatment inhibits the proliferation and function of group 2 innate lymphoid cells (ILC2) through an IFNAR1-dependent mechanism. We further show that internalization of 2′3′-cGAMP by alveolar macrophages activates STING-IRF3 signaling to induce the production of IFNα in mouse lungs. Taken together, our results present a proof-of-concept evidence to support a therapeutic value of 2′3′-cGAMP in preventing acute lung inflammation in a mouse model of allergic asthma.
Antifibrotics Modify B-cell Induced Fibroblast Migration and Activation in IPF Patients
Authors: Ali Mohamed , Egan Ashley M , Shaughnessy Gaja F , Dasari Harika , Van Keulen Virginia P. , Aubry Marie Christine , Limper Andrew H , Peikert Tobias , Carmona Eva M
Published: January 2023

Background

Acute respiratory exacerbations in idiopathic pulmonary fibrosis (IPF), often triggered by infection, are life threatening events characterized by rapid deterioration of lung function and associated with poor prognosis. Since microbial antigens modulate immunity by activating different pattern recognition receptors (PRR) expressed by innate immune cells (including B-cells), we sought to investigate how the activation of human B-cells through PRR stimulation by different microbial (CpG and β-glucan) and non-microbial (Mitochondrial DAMPs; MTDs) antigens resulted in the release of an inflammatory/fibrotic milieu that contributed to the pathogenesis of fibrosis in patients with IPF.

Results

Our results show that an inflammatory milieu is induced by stimulating circulating B-cells with both noninfectious (MTDs) and infectious antigens (CpG and β-glucan) commonly found in bacteria and fungi. Moreover, we show that the inflammatory milieu produced was specific to the inducing antigen, and that the microbial antigens (CpG and β-glucan) triggered distinct signaling pathways in B-cells. Specifically, CpG induced mTOR-activation while β-glucan was mTOR-independent and activated Src and p38. Furthermore, our results also show that B-cell aggregates are present within fibrotic areas of the lung in IPF patients and activated B-cells induce fibroblast migration, which was modified by antifibrotics (nintedanib and pirfenidone).

Conclusion

Our results highlight the potential contribution of activated B-cells through PRRs to the proinflammatory and profibrotic milieu seen in patients with idiopathic pulmonary fibrosis.
Eosinophil accumulation in postnatal lung is specific to the primary septation phase of development
Authors: Coden Mackenzie , Loffredo Lucas F , Jeong Brian M , Walker Matthew , Anekalla Kishore Reddy , Doan Ton , Rodriguez Raul , Browning Mandy , Nam Kiwon , Lee James , Abdala-Valencia Hiam , Berdnikovs Sergejs
Published: January 2023

Type 2 immune cells and eosinophils are transiently present in lung tissue not only in pathology but also during normal postnatal development. However, the lung developmental processes underlying postnatal airway recruitment of eosinophils after birth remain unexplored. We determined that in mice, mature eosinophils are recruited to the lung during P3–14, which corresponds to the primary septation/alveolarization phase of lung development. Developmental eosinophils peaked during P10–14 and exhibited Siglec-Fmed/highCD11c−/low phenotypes, similar to allergic asthma models. By interrogating the lung transcriptome and proteome during peak eosinophil recruitment in postnatal development, we identified markers that functionally capture mesenchymal-epithelial interface establishment (Nes, Smo, Wnt5a, Nog) and provisional extracellular matrix (ECM) deposition (Tnc, Postn, Spon2, Thbs2) as key lung morphogenetic events associating with eosinophils. We identifiedTenascin-C (TNC) as one of the key ECM markers in the lung epithelial-mesenchymal interface at the RNA and protein levels, consistently associating with eosinophils in development and disease. By RNA-seq analysis, naïve murine eosinophils cultured with TNC-enriched ECM significantly induced expression of Siglec-F, CD11c, eosinophil peroxidase, and other markers typical for activated eosinophils in development and allergic inflammatory responses. TNC knockout mice had an altered eosinophil recruitment profile in development. Collectively, our results indicate that lung morphogenetic processes associated with heightened Type 2 immunity are not merely tissue “background” but specifically guide immune cells both in development and pathology.
Human Chorionic Gonadotropin acts as a central regulator of adaptive immune responses during early pregnancy safeguarding fetal survival
Authors: Schumacher Anne , Zenclussen Ana
Published: January 2023

A perfect interplay between the endocrine system and the maternal immune system is pivotal for early fetal tolerance induction. Particularly, the placenta-derived hormone human chorionic gonadotropin (hCG) that is secreted during early pregnancy stages and is suggested to regulate pro- and anti-inflammatory maternal immune responses. However, the precise mechanisms underlying hCG-driven immunoregulation are far from being understood. Thus, we performed several studies to illuminate the participation of hCG in immunomodulation with a specific focus on T and B cell responses.

We included human and mouse material in our studies to analyze the influence of hCG on the generation, plasticity and functionality of regulatory T (Treg) cells, Th17 cells and B cells using different in vitro assays. In vivo, we applied hCG during the peri-implantation period into abortion-prone mice and analyzed Treg proportions and activity.

Our in vitro results revealed that hCG attracts human Treg, promotes formation of human and mouse Treg and increases T cell suppressive activity in both species. Moreover, hCG inhibits mouse Th17 differentiation and induces Th17 cells with anti-inflammatory phenotypes in the mouse system. Human B cells adopt a regulatory phenotype and start to secrete fetal-protective asymmetric antibodies upon hCG stimulation in vitro. In vivo, hCG application into abortion-prone mice restored Treg levels, augmented Treg suppressive activity and rescued fetuses from rejection.

In summary, our findings suggest that hCG contributes to early fetal tolerance induction by shifting maternal adaptive immune responses towards an anti-inflammatory profile.
Lymphocytes in autoimmune-resistant mice may protect the islets through IL-10 production
Authors: Whitesell Jennifer C , Lindsay Robin S , Yannacone Seth , Olivas-Corral Jessica , Lucas Erin , Friedman Rachel S.
Published: January 2023

We have identified T cells and B cells in the islets of autoimmune resistant mice, yet the role of these lymphocytes is unknown. In the islets of autoimmune resistant C57BL/6 mice, local antigen receptor signaling was assessed using Nur77-GFP mice. Nur77-GFP expression was increased in islet CD8+ T cells and B cells suggesting that these lymphocyte subsets receive local antigenic stimulus. Islet T cell and B cell populations expressed the regulatory cytokine IL-10, assessed using the B6.TIGER reporter mouse. T cell populations lacked expression of the pro-inflammatory cytokine IFN-γ. These findings indicate that islet T cell populations are likely playing a regulatory role. In addition, cultured whole islets produced IL-10 protein, but not IFN-γ protein. To test the stability of the islet lymphocyte populations under inflammatory conditions, mice were exposed to metabolic stress through a diet-induced obesity (DIO) model. Obesity and type 2 diabetes (T2D) are associated with circulating inflammatory cytokines. In T2D patients, islet lymphocytes have been identified, though the function of these populations is largely unknown. C57BL/6 mice were fed a high fat diet (DIO) or a matched control diet (Control) starting at 5 weeks of age, and then analyzed at 16–25 weeks of age. The number and phenotype of lymphocytes in the islets were similar in DIO and control mice. Notably, under the conditions of obesity-associated systemic inflammation, islet lymphocytes in the DIO mice maintained IL-10 production. From these data, we propose that islet lymphocytes play a regulatory role to protect the islets from systemic inflammation through IL-10 production.
Age-related changes in the immune phenotype of human memory CD4 T cells differ between colon and peripheral blood
Authors: Wilson Cara C , Dillon Stephanie
Published: January 2023

Gut lamina propria (LP) CD4 T cells are primarily tissue resident memory cells that are critical in maintaining gut homeostasis and responding to enteric pathogens. We established that aging altered the phenotypic and functional profiles of human small intestinal CD4 T cells. However, given site-specific differences in immune cell composition in the gut, it is difficult to extrapolate these findings to other locations. To probe the effect of aging on large intestine CD4 T cells, we used flow cytometry to analyze immune phenotypes of colon LP CD4 T cells from younger (34±2yrs mean±SEM; N=6) and older (80±2yrs, N=6) adults. Tissue-specificity of these profiles was determined by comparing to memory (CD45RA−) peripheral blood (mPB) CD4 T cells in a separate cohort of similarly aged persons (N=6/age group). Among younger samples, LP CD4 T cells expressed higher levels of co-inhibitory molecules CTLA4 and PD1, but had lower turnover (Ki67+) and IL2 receptor (CD25) expression relative to mPB CD4 T cells. Expression of activation (CD38, HLA-DR), senescence (CD57) and survival (Bcl2) markers were similar. Regarding age effects, frequencies of LP CD4 T cells (% of CD3 T cells) were similar between older and younger samples; mPB CD4 T cell frequencies were higher in older vs younger samples. Older LP CD4 T cells had lower CTLA4, PD1, CD38, CD25 and Ki67 and higher Bcl2 expression than younger LP CD4 T cells. Among mPB CD4 T cells, greater age was only associated with a higher CD57+ fraction. Thus, age effects differed between colon LP and mPB CD4 memory T cells. Loss of co-inhibitory markers, decreased turnover and increased survival of colon LP CD4 T cells may contribute to altered homeostasis, loss of protective immunity, and chronic inflammation in older people.
The role of old age on Mycobacterium bovis BCG vaccine-induced tissue immunity
Authors: Scordo Julia M , Piergallini Tucker J , Headley Colwyn A , Hodara Vida , Reuter Nicole , Papin James F , Turner Joanne
Published: January 2023

Infections account for one-third of deaths in elderly individuals. Vaccines are a primary tool to combat infection, yet they are less effective in the elderly population. While many groups have aimed to address this problem by studying vaccine-induced peripheral blood responses in the elderly, work from our lab demonstrates that immune responses to vaccination and infectious challenge differ between tissue sites and the periphery. To improve health outcomes in our aged population, we must study vaccine-responses in both the periphery and the local infection site (the tissue). We study this through a delayed-type hypersensitivity model of Mycobacterium bovis BCG vaccination and subsequent tuberculin skin test (TST) eight weeks after vaccination in adult and elderly baboons. Vaccination generates BCG-specific immune cells that are recruited to the skin upon TST challenge which we can study in skin biopsies reflecting tissue specific responses. Three days or one week after TST we examine BCG-specific memory responses in the skin biopsies. We also determine BCG-induced responses in the blood to compare tissue and systemic responses. We find increased oxidation and decreased production of cytokines, chemokines and growth factors in aged baboon skin at the site of TST challenge, despite no alteration in vaccine-induced peripheral blood responses between age groups. Based on these findings, we anticipate that alterations in the skin of aged BCG-vaccinated baboons will hinder T cell migration to and function in the tissue, thus decreasing vaccine-induced tissue immunity.
Human gingiva-derived mesenchymal stem cells are therapeutic in lupus nephritis through targeting of CD39-CD73 signaling pathway
Authors: Wang Julie , Dang Junlong , Zheng Song Guo
Published: January 2023

Cell specific and cytokine targeted therapeutics have underperformed in systemic lupus erythematosus (SLE). Mesenchymal stem cells (MSCs) have emerged as a novel therapy to address the dysregulation in autoimmune diseases but also have limitations. Human gingiva derived MSCs (GMSCs) are superior in regulating immune responses. Here, we demonstrate that the adoptively transferred GMSC home to and maintain in the kidney and have a robust therapeutic effect in a spontaneous lupus nephritis model. Specifically, GMSCs limits the development of autoantibodies as well as proteinuria, decreases the frequency of plasma cells and lupus nephritis histopathological scores by directly suppressing B cells activation, proliferation and differentiation. The blockage of CD39-CD73 pathway dramatically abrogated the suppressive capacities of GMSCs in vitro and in vivo and highlights the significance of this signaling pathway in SLE. Collectively, manipulation of GMSCs provides a promising strategy for the treatment of patients with SLE and other autoimmune diseases.
PT101: A Treg selective agonist IL-2 mutein therapy for autoimmunity
Authors: Higginson-Scott Nathan , Otipoby Kevin L. , Viney Jo
Published: January 2023

Regulatory T cells (Treg) play a critical role in immune homeostasis and are dysfunctional in many autoimmune diseases. Interleukin 2 (IL-2), via the heterotrimeric IL-2 receptor (CD25/CD122/CD132), drives the proliferation and function of Treg. CD25 loss-of-function in mice is associated with Treg deficiency and widespread autoimmunity. Low dose IL-2 expands Tregs and is being evaluated therapeutically, however it has a narrow selectivity window over conventional T cells and Natural Killer cells which is dose limiting. To enhance IL-2 selectivity for activating and expanding Treg, mutations can be introduced that create a dependency on CD25 binding for signaling through CD122/CD132 upon IL-2 facilitated CD25/CD122/CD132 trimer formation. We created PT101, a mutant IL-2 Fc fusion, containing a N88D mutation that significantly decreases CD122 binding affinity in addition to other mutations that increase CD25 binding affinity and introduce improved molecular stability and drug-like properties. We found that PT101 selectively induces STAT5 phosphorylation in human and cynomolgus monkey Tregs in vitro. In humanized NOD-scid IL-2Rg-null (NSG) mice and cynomolgus monkeys, single or multiple dose administration of PT101 dose-dependently and selectively expands Treg without significant effects on other immune cell types, and without eliciting proinflammatory cytokine production. A 1-month toxicity study in cynomolgus monkeys indicated that PT101 was safe and well-tolerated at 300× the minimum efficacious dose whilst maintaining its Treg selectivity. PT101 is being evaluated in a randomized, placebo-controlled, double-blind, single ascending dose-escalation trial in healthy volunteers.