Browsing by Author "Eden, Kristin"

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    Antibiotics ameliorate lupus-like symptoms in mice
    Mu, Qinghui; Tavella, Vincent J.; Kirby, Jay L.; Cecere, Thomas E.; Chung, Matthias; Lee, Jiyoung; Li, Song; Ahmed, Sattar Ansar; Eden, Kristin; Allen, Irving C. (Nature, 2017-10-20)
    Gut microbiota and the immune system interact to maintain tissue homeostasis, but whether this interaction is involved in the pathogenesis of systemic lupus erythematosus (SLE) is unclear. Here we report that oral antibiotics given during active disease removed harmful bacteria from the gut microbiota and attenuated SLE-like disease in lupus-prone mice. Using MRL/lpr mice, we showed that antibiotics given after disease onset ameliorated systemic autoimmunity and kidney histopathology. They decreased IL-17-producing cells and increased the level of circulating IL-10. In addition, antibiotics removed Lachnospiraceae and increased the relative abundance of Lactobacillus spp., two groups of bacteria previously shown to be associated with deteriorated or improved symptoms in MRL/lpr mice, respectively. Moreover, we showed that the attenuated disease phenotype could be recapitulated with a single antibiotic vancomycin, which reshaped the gut microbiota and changed microbial functional pathways in a time-dependent manner. Furthermore, vancomycin treatment increased the barrier function of the intestinal epithelium, thus preventing the translocation of lipopolysaccharide, a cell wall component of Gram-negative Proteobacteria and known inducer of lupus in mice, into the circulation. These results suggest that mixed antibiotics or a single antibiotic vancomycin ameliorate SLE-like disease in MRL/lpr mice by changing the composition of gut microbiota.
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    Case Report: Disorder of Sexual Development in a Chinese Crested Dog With XX/XY Leukocyte Chimerism and Mixed Cell Testicular Tumors
    Schwartz, Rebecca; Sugai, Nicole J.; Eden, Kristin; Castaneda, Caitlin; Jevit, Matthew; Raudsepp, Terje; Cecere, Julie T. (Frontiers, 2022-07-08)
    A 10-year-old intact female Chinese Crested dog was presented for evaluation and further diagnostics due to persistent symptoms of vulvar swelling, vaginal discharge, and an 8-year history of acyclicity. At presentation, generalized hyperpigmentation and truncal alopecia were identified, with no aberrations of the female phenotype. Vaginal cytology confirmed the influence of estrogen at multiple veterinary visits, and hormonal screening of progesterone and anti-Mullerian hormone indicated gonadal presence. Based on findings from abdominal laparotomy and gonadectomy, the tissue was submitted for histopathology. Histopathologic evaluation identified the gonads to be abnormal testes containing multiple Sertoli and interstitial (Leydig) cell tumors. The histopathologic diagnosis of testes and concurrent normal external female phenotype in the patient lead to a diagnosis of a disorder of sexual development (DSD). Karyotype evaluation by conventional and molecular analysis revealed a two cell line chimeric pattern of 78,XX (80%) and 78,XY (20%) among blood leukocytes, as well as a positive PCR test for the Y-linked SRY gene. Cytogenetic analysis of skin fibroblasts revealed the presence of 78,XX cells exclusively, and PCR tests for the Y-linked SRY gene were negative in the hair and skin samples. These results are consistent with an XX/XY blood chimerism. This is one of the few case reports of a canine with the diagnosis of leukocyte chimerism with normal female phenotypic external genitalia. This case illustrates a distinct presentation for hormonally active Sertoli cell tumorigenesis and demonstrates surgery as a curative treatment option for clinically affected patients.
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    EGR2 Deletion Suppresses Anti-DsDNA Autoantibody and IL-17 Production in Autoimmune-Prone B6/lpr Mice: A Differential Immune Regulatory Role of EGR2 in B6/lpr Versus Normal B6 Mice
    Dai, Rujuan; Wang, Zhuang; Heid, Bettina; Eden, Kristin; Reilly, Christopher M.; Ahmed, S. Ansar (Frontiers, 2022-06-15)
    Previous studies have reported that deletion of the transcription factor, early growth response protein 2 (EGR2), in normal C57BL/6 (B6) resulted in the development of lupus-like autoimmune disease. However, increased EGR2 expression has been noted in human and murine lupus, which challenges the notion of the autoimmune suppressive role of EGR2 in B6 mice. In this study, we derived both conditional EGR2-/-B6/lpr and EGR2-/-B6 mice to elucidate the immune and autoimmune regulatory roles of EGR2 in autoinflammation (B6/lpr) versus physiologically normal (B6) conditions. We found that conditional EGR2 deletion increased spleen weight, enhanced T cell activation and IFNγ production, and promoted germinal center B cells and LAG3+ regulatory T cells development in both B6/lpr and B6 mice. Nevertheless, EGR2 deletion also showed strikingly differential effects in these two strains on T lymphocyte subsets profile, Foxp3+ Tregs and plasma cell differentiation, anti-dsDNA autoantibodies and immunoglobulins production, and on the induction of IL-17 in in vitro activated splenocytes. Specifically, EGR2 deletion in B6/lpr mice significantly decreased serum levels of anti-dsDNA autoantibodies, total IgG, IgM, IgG1, and IgG2a with reduced plasma cells differentiation. Furthermore, EGR2 deletion in B6/lpr mice had no obvious effect on IgG immunocomplex deposition, medium caliber vessel, and glomeruli inflammation but increased complement C3 immunocomplex deposition and large caliber vessel inflammation in the kidneys. Importantly, we demonstrated that EGR2 deletion in B6/lpr mice significantly reduced pathogenic CD4-CD8-CD3+B220+ double negative T cells, which correlated with the reduced anti-dsDNA autoantibodies in serum and decreased IL-17 production in splenocytes of EGR2-/-B6/lpr mice. Together, our data strongly suggest that the role of EGR2 is complex. The immunoregulatory role of EGR2 varies at normal or autoinflammation conditions and should not be generalized in differential experimental settings.
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    High-frequency irreversible electroporation is an effective tumor ablation strategy that induces immunologic cell death and promotes systemic anti-tumor immunity
    Ringel-Scaia, Veronica M.; Beitel-White, Natalie; Lorenzo, Melvin F.; Brock, Rebecca M.; Huie, Kathleen E.; Coutermarsh-Ott, Sheryl; Eden, Kristin; McDaniel, Dylan K.; Verbridge, Scott S.; Rossmeisl, John H. Jr.; Oestreich, Kenneth J.; Davalos, Rafael V.; Allen, Irving C. (2019-06)
    Background: Despite promising treatments for breast cancer, mortality rates remain high and treatments for metastatic disease are limited. High-frequency irreversible electroporation (H-FIRE) is a novel tumor ablation technique that utilizes high-frequency bipolar electric pulses to destabilize cancer cell membranes and induce cell death. However, there is currently a paucity of data pertaining to immune system activation following H-FIRE and other electroporation based tumor ablation techniques. Methods: Here, we utilized the mouse 4T1 mammary tumor model to evaluate H-FIRE treatment parameters on cancer progression and immune system activation in vitro and in vivo. Findings: H-FIRE effectively ablates the primary tumor and induces a pro-inflammatory shift in the tumor microenvironment. We further show that local treatment with H-FIRE significantly reduces 4T1 metastases. H-FIRE kills 4T1 cells through non-thermal mechanisms associated with necrosis and pyroptosis resulting in damage associated molecular pattern signaling in vitro and in vivo. Our data indicate that the level of tumor ablation correlates with increased activation of cellular immunity. Likewise, we show that the decrease in metastatic lesions is dependent on the intact immune system and H-FIRE generates 4T1 neoantigens that engage the adaptive immune system to significantly attenuate tumor progression. Interpretation: Cell death and tumor ablation following H-FIRE treatment activates the local innate immune system, which shifts the tumor microenvironment from an anti-inflammatory state to a pro-inflammatory state. The non-thermal damage to the cancer cells and increased innate immune system stimulation improves antigen presentation, resulting in the engagement of the adaptive immune system and improved systemic anti-tumor immunity. (C) 2019 The Authors. Published by Elsevier B.V.
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    Histotripsy Ablation in Preclinical Animal Models of Cancer and Spontaneous Tumors in Veterinary Patients: A Review
    Hendricks-Wenger, Alissa; Arnold, Lauren; Gannon, Jessica; Simon, Alex; Singh, Neha; Sheppard, Hannah; Nagai-Singer, Margaret A.; Imran, Khan Mohammed; Lee, Kiho; Clark-Deener, Sherrie; Byron, Christopher R.; Edwards, Michael R.; Larson, Martha M.; Rossmeisl, John H. Jr.; Coutermarsh-Ott, Sheryl; Eden, Kristin; Dervisis, Nikolaos G.; Klahn, Shawna L.; Tuohy, Joanne L.; Allen, Irving C.; Vlaisavljevich, Eli (IEEE, 2021-09-03)
    New therapeutic strategies are direly needed in the fight against cancer. Over the last decade, several tumor ablation strategies have emerged as stand-alone or combination therapies. Histotripsy is the first completely noninvasive, nonthermal, and nonionizing tumor ablation method. Histotripsy can produce consistent and rapid ablations, even near critical structures. Additional benefits include real-time image guidance, high precision, and the ability to treat tumors of any predetermined size and shape. Unfortunately, the lack of clinically and physiologically relevant preclinical cancer models is often a significant limitation with all focal tumor ablation strategies. The majority of studies testing histotripsy for cancer treatment have focused on small animal models, which have been critical in moving this field forward and will continue to be essential for providing mechanistic insight. While these small animal models have notable translational value, there are significant limitations in terms of scale and anatomical relevance. To address these limitations, a diverse range of large animal models and spontaneous tumor studies in veterinary patients have emerged to complement existing rodent models. These models and veterinary patients are excellent at providing realistic avenues for developing and testing histotripsy devices and techniques designed for future use in human patients. Here, we provide a review of animal models used in preclinical histotripsy studies and compare histotripsy ablation in these models using a series of original case reports across a broad spectrum of preclinical animal models and spontaneous tumors in veterinary patients.
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    An integrated pre-clerkship curriculum to build cognitive medical schema: It’s not just about the content
    LeClair, Renee J.; Cleveland, Jennifer L.; Eden, Kristin; Binks, Andrew P. (Frontiers, 2023-03-16)
    Both physiology and pathophysiology are essential disciplines in health professional education however, clinicians do not use this knowledge in isolation. Instead, physicians use inter-disciplinary concepts embedded within integrated cognitive schema (illness scripts) established through experience/knowledge that manifest as expert-level thinking. Our goal was to develop a pre-clerkship curriculum devoid of disciplinary boundaries (akin to the physician’s illness script) and enhance learners’ clerkship and early clinical performance. As well as developing curricular content, the model considered non-content design elements such as learner characteristics and values, faculty and resources and the impact of curricular and pedagogical changes. The goals of the trans-disciplinary integration were to develop deep learning behaviors through, 1) developing of integrated, cognitive schema to support the transition to expert-level thinking, 2) authentic, contextualization to promote knowledge transfer to the clinical realm 3) allowing autonomous, independent learning, and 4) harnessing the benefits of social learning. The final curricular model was a case-based approach with independent learning of basic concepts, differential diagnosis and illness scripting writing, and concept mapping. Small-group classroom sessions were team-taught with basic scientists and physicians facilitating learners’ self-reflection and development of clinical reasoning. Specifications grading was used to assess the products (written illness scripts and concept maps) as well as process (group dynamics) while allowing a greater degree of learner autonomy. Although the model we adopted could be transferred to other program settings, we suggest it is critical to consider both content and non-content elements that are specific to the environment and learner.
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    Maternal Influence and Murine Housing Confound Impact of NLRP1 Inflammasome on Microbiome Composition
    Ringel-Scaia, Veronica M.; Qin, Yufeng; Thomas, Cassidy A.; Huie, Kathleen E.; McDaniel, Dylan K.; Eden, Kristin; Wade, Paul A.; Allen, Irving C. (2019-02-13)
    The NLRP1 inflammasome attenuates inflammatory bowel disease (IBD) progression and colitis-associated tumorigenesis. A possible mechanism postulates that the lack of the NLRP1 inflammasome creates permissive niches in the gut for pathogenic bacteria to flourish, causing dysbiosis and increased IBD susceptibility. To evaluate this hypothesis, we characterized the gut microbiome of wild-type, Nlrp1b-/-, and Asc-/- mice under naive conditions by sequencing the V3 region of the 16s rRNA gene. For both genetically modified mouse lines, the microbiome composition reflected overrepresentation of bacteria associated with dysbiosis relative to wild-type animals. Measurement of short- and medium-chain fatty acids by mass spectrometry further revealed significant differences between genotypes. However, prior to concluding that the NLRP1 inflammasome plays a role in regulating the composition of the microbiome, we evaluated two additional strategies for cohousing wild-type and Nlrp1b-/- mice: breeding homozygous parents and cohousing at weaning, and breeding from heterozygous parents and cohousing littermates. We found that maternal influence was the greater predictor of microbiome composition rather than genotype. With the rise in microbiome research across disciplines, our study should be viewed as a cautionary example that illustrates the importance of careful breeding and housing strategies when evaluating host-microbiome interactions. (C) 2019 The Author(s) Published by S. Karger AG, Basel
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    NF-κB Inducing Kinase Attenuates Colorectal Cancer by Regulating Noncanonical NF-κB Mediated Colonic Epithelial Cell Q1 Regeneration
    Morrison, Holly A.; Eden, Kristin; Trusiano, Brie; Rothschild, Daniel E.; Qin, Yufeng; Wade, Paul A.; Rowe, Audrey J.; Mounzer, Christina; Stephens, Morgan C.; Hanson, Katherine M.; Brown, Stephan L.; Holl, Eda K.; Allen, Irving C. (Elsevier, 2024-06)
    BACKGROUND & AIMS: Dysregulated colonic epithelial cell (CEC) proliferation is a critical feature in the development of colorectal cancer. We show that NF-𝜅B-inducing kinase (NIK) attenuates colorectal cancer through coordinating CEC regeneration/ differentiation via noncanonical NF-𝜅B signaling that is unique from canonical NF-𝜅B signaling. METHODS: Initial studies evaluated crypt morphology/functionality, organoid generation, transcriptome profiles, and the microbiome. Inflammation and inflammation-induced tumorigenesis were initiated in whole-body NIK knockout mice (Nik⁻/⁻) and conditional-knockout mice following administration of azoxymethane and dextran sulfate sodium. RESULTS: Human transcriptomic data revealed dysregulated noncanonical NF-𝜅B signaling. In vitro studies evaluating Nik⁻/⁻ crypts and organoids derived from mature, nondividing CECs, and colonic stem cells exhibited increased accumulation and stunted growth, respectively. Transcriptomic analysis of Nik⁻/⁻ cells revealed gene expression signatures associated with altered differentiation-regeneration. When assessed in vivo, Nik⁻/⁻ mice exhibited more severe colitis with dextran sulfate sodium administration and an altered microbiome characterized by increased colitogenic microbiota. In the inflammationinduced tumorigenesis model, we observed both increased tumor burdens and inflammation in mice where NIK is knocked out in CECs (NikΔCEC). Interestingly, this was not recapitulated when NIK was conditionally knocked out in myeloid cells (NikΔMYE). Surprisingly, conditional knockout of the canonical pathway in myeloid cells (RelAΔMYE) revealed decreased tumor burden and inflammation and no significant changes when conditionally knocked out in CECs (RelAΔCEC) CONCLUSIONS: Dysregulated noncanonical NF-𝜅B signaling is associated with the development of colorectal cancer in a tissue-dependent manner and defines a critical role for NIK in regulating gastrointestinal inflammation and regeneration associated with colorectal cancer.
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    NLRX1 Deficiency Alters the Gut Microbiome and Is Further Exacerbated by Adherence to a Gluten-Free Diet
    Morrison, Holly A.; Liu, Yang; Eden, Kristin; Nagai-Singer, Margaret A.; Wade, Paul A.; Allen, Irving C. (Frontiers, 2022-04-28)
    Patients with gluten sensitivities present with dysbiosis of the gut microbiome that is further exacerbated by a strict adherence to a gluten-free diet (GFD). A subtype of patients genetically susceptible to gluten sensitivities are Celiac Disease (CeD) patients, who are carriers of the HLA DR3/DQ2 or HLA DR4/DQ8 haplotypes. Although 85-95% of all CeD patients carry HLA DQ2, up to 25-50% of the world population carry this haplotype with only a minority developing CeD. This suggests that CeD and other gluten sensitivities are mediated by factors beyond genetics. The contribution of innate immune system signaling has been generally understudied in the context of gluten sensitivities. Thus, here we examined the role of NOD-like receptors (NLRs), a subtype of pattern recognition receptors, in maintaining the composition of the gut microbiome in animals maintained on a GFD. Human transcriptomics data revealed significant increases in the gene expression of multiple NLR family members, across functional groups, in patients with active CeD compared to control specimens. However, NLRX1 was uniquely down-regulated during active disease. NLRX1 is a negative regulatory NLR that functions to suppress inflammatory signaling and has been postulate to prevent inflammation-induced dysbiosis. Using Nlrx1(-/-) mice maintained on either a normal or gluten-free diet, we show that loss of NLRX1 alters the microbiome composition, and a distinctive shift further ensues following adherence to a GFD, including a reciprocal loss of beneficial microbes and increase in opportunistic bacterial populations. Finally, we evaluated the functional impact of an altered gut microbiome by assessing short- and medium-chain fatty acid production. These studies revealed significant differences in a selection of metabolic markers that when paired with 16S rRNA sequencing data could reflect an overall imbalance and loss of immune system homeostasis in the gastrointestinal system.
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    Noncanonical NF-kappa B Signaling Upregulation in Inflammatory Bowel Disease Patients is Associated With Loss of Response to Anti-TNF Agents
    Nguyen, Vu Q.; Eden, Kristin; Morrison, Holly A.; Sammons, Megan B.; Knight, Kristin K.; Sorrentino, Siena; Brock, Rebecca M.; Grider, Douglas J.; Allen, Irving C.; Sorrentino, Dario (2021-06-10)
    Objectives: Targeting tumor necrosis factor (TNF) with biologic agents, such as infliximab and adalimumab, is a widely used and effective therapeutic strategy in inflammatory bowel disease (IBD). Unfortunately, a significant number of patients fail to respond or lose response over time to these agents. Previous studies have defined multiple complex roles for canonical NF-kappa B signaling in the pathogenesis of IBD. However, preliminary evidence suggests that the lesser defined noncanonical NF-kappa B signaling pathway also contributes to disease pathogenesis and response to anti-TNF agents. The objective of this study was to evaluate this hypothesis in Crohn's disease (CD) and ulcerative colitis (UC) patients. Design: A total of 27 subjects with IBD (19 with CD and 8 with UC) and 15 control subjects were tested. Clinical criteria, patient history, and endoscopic disease activity were factors used to categorize patients and define therapeutic response. Biopsy specimens were collected during colonoscopy and expression was determined for 88 target genes known to be associated with noncanonical NF-kappa B signaling and IBD. Results: Noncanonical NF-kappa B signaling was significantly upregulated in IBD patients and was associated with increased gastrointestinal inflammation, epithelial cell death, lymphocyte migration, and Nod-like receptor signaling. Furthermore, noncanonical NF-kappa B signaling was further upregulated in patients unresponsive to anti-TNF agents and was suppressed in responsive patients. MAP3K14, NFKB2, CCL19, CXCL12, and CXCL13 were significantly dysregulated, as were genes that encode pathway regulators, such as CYLD, NLRP12, and BIRC2/3. Conclusion: Our study identifies a previously uncharacterized role for the understudied noncanonical NF-kappa B signaling pathway in the pathogenesis of IBD and anti-TNF therapy responsiveness. The genes and pathways identified may ultimately prove useful in IBD management and could potentially be used as biomarkers of drug response.
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    Noncanonical NF-KB in Gastrointestinal Disease
    Eden, Kristin (Virginia Tech, 2018-11-20)
    Noncanonical NF-KB is an alternative NF-KB pathway that is critically involved in the development and maturation of the adaptive immune system. As such, it has typically been studied in B and T cell biology without application to complex organ systems such as the gut. The following work explores the contribution of noncanonical NF-KB to inflammatory and neoplastic disease in the gastrointestinal (GI) system, as well as the effects of its loss on GI health. Chapter 1 opens with an overview of gastrointestinal homeostasis and inflammation, with emphasis on the particular diseases studied in this body of work. Chapter 2 focuses on a review of noncanonical NF-KB function and components, as well as its applications in inflammatory bowel disease (IBD), a quintessential example of disruption of intestinal homeostasis. In Chapter 3 we determine the role of noncanonical NF-KB in allergic disease of the upper gastrointestinal tract, namely a novel model of the disease eosinophilic esophagitis. Our studies revealed that loss of NF-KB-inducing kinase (NIK), the bottleneck molecule in noncanonical NF-KB signaling, results in targeted esophageal inflammation, remodeling, and gene expression changes that are comparable to the human disease. In Chapter 4, we examine the role of noncanonical NF-KB in inflammatory bowel disease using biopsy samples from human IBD patients, and compare the expression of various components of the pathway to inflammation status and treatment response. Noncanonical NF-KB is upregulated in IBD patients, and also appears to be specifically upregulated in patients that have lost response to anti-TNF inhibitors, which are potent drugs that are widely used to treat IBD. In Chapter 5 we focus on NIK and its effects on stem cell function, growth, and inflammation-induced cancer in the gut. Loss of NIK in mice results in alterations in colonic stem cell function and changes in colonic microbiome, which predisposes them to the development of inflammation-induced carcinogenesis. Indeed, in human patients with colorectal cancer, noncanonical NF-KB is also suppressed. Overall, we have discovered multiple novel roles of noncanonical NF-KB signaling at multiple levels in the gut and in the context of a variety of diseases, and have greatly expanded the current body of knowledge as to the functions and effects of this pathway.
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    Noncanonical NF-κB signaling and the essential kinase NIK modulate crucial features associated with eosinophilic esophagitis pathogenesis
    Eden, Kristin; Rothschild, Daniel E.; McDaniel, Dylan K.; Heid, Bettina; Allen, Irving C. (The Company of Biologists, 2017)
    Eosinophilic esophagitis (EoE) is an allergic disease of the esophagus driven by T cell and eosinophil responses to dietary allergens, resulting in chronic mucosal inflammation. Few spontaneous animal models of esophageal eosinophilia exist, with most studies relying on artificial sensitization procedures. NF-κBinducing kinase (NIK; MAP3K14) is a key signaling molecule of the noncanonical NF-κB (NFKB1) pathway, an alternative signaling cascade producing chemokines involved in lymphoid stroma development and leukocyte trafficking. Nik−/− mice have been shown to develop a hypereosinophilic syndrome in peripheral blood and major filtering organs; however, the gastrointestinal mucosa of these mice has not been well characterized. We show that Nik−/− mice develop significant, localized eosinophilic esophagitis that mimics human EoE, including features such as severe eosinophil accumulation, degranulation, mucosal thickening, fibrosis and basal cell hyperplasia. The remainder of the GI tract, including the caudal stomach, small intestine and colon, in mice with active EoE are unaffected, also similar to human patients. Gene expression patterns in esophageal tissue of Nik−/− mice mimics human EoE, with thymic stromal lymphopoetin (TSLP) in particular also elevated at the protein level. In gene expression data sets from human biopsy specimens, we further show that many genes associated with noncanonical NF- κB signaling are significantly dysregulated in EoE patients, most notably a paradoxical upregulation of NIK itself with concurrent upregulation of powerful protein-level destabilizers of NIK. These findings suggest that Nik−/− mice could be useful as a spontaneous model of specific features of EoE and highlight a novel role for noncanonical NF-κB signaling in human patients.
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    Quaternary Ammonium Compound Disinfectants Reduce Lupus-Associated Splenomegaly by Targeting Neutrophil Migration and T-Cell Fate
    Abdelhamid, Leila; Cabana-Puig, Xavier; Mu, Qinghui; Moarefian, Maryam; Swartwout, Brianna K.; Eden, Kristin; Das, Prerna; Seguin, Ryan P.; Xu, Libin; Lowen, Sarah; Lavani, Mital; Hrubec, Terry C.; Jones, Caroline N.; Luo, Xin M. (2020-10-21)
    Hypersensitivity reactions and immune dysregulation have been reported with the use of quaternary ammonium compound disinfectants (QACs). We hypothesized that QAC exposure would exacerbate autoimmunity associated with systemic lupus erythematosus (lupus). Surprisingly, however, we found that compared to QAC-free mice, ambient exposure of lupus-prone mice to QACs led to smaller spleens with no change in circulating autoantibodies or the severity of glomerulonephritis. This suggests that QACs may have immunosuppressive effects on lupus. Using a microfluidic device, we showed that ambient exposure to QACs reduced directional migration of bone marrow-derived neutrophils toward an inflammatory chemoattractant ex vivo. Consistent with this, we found decreased infiltration of neutrophils into the spleen. While bone marrow-derived neutrophils appeared to exhibit a pro-inflammatory profile, upregulated expression of PD-L1 was observed on neutrophils that infiltrated the spleen, which in turn interacted with PD-1 on T cells and modulated their fate. Specifically, QAC exposure hindered activation of splenic T cells and increased apoptosis of effector T-cell populations. Collectively, these results suggest that ambient QAC exposure decreases lupus-associated splenomegaly likely through neutrophil-mediated toning of T-cell activation and/or apoptosis. However, our findings also indicate that even ambient exposure could alter immune cell phenotypes, functions, and their fate. Further investigations on how QACs affect immunity under steady-state conditions are warranted.
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    Regulation of neonatal IgA production by the maternal microbiota
    Mu, Qinghui; Swartwout, Brianna K.; Edwards, Michael R.; Zhu, Jing; Lee, Grace; Eden, Kristin; Cabana-Puig, Xavier; McDaniel, Dylan K.; Mao, Jiangdi; Abdelhamid, Leila; Brock, Rebecca M.; Allen, Irving C.; Reilly, Christopher M.; Luo, Xin M. (National Academy of Sciences, 2021-02-22)
    Infants are prone to enteric infections due to an underdeveloped immune system. The maternal microbiota, through shaping the neonatal microbiota, helps establish a strong immune system in infants. We and others have observed the phenomenon of enhanced early neonatal immunoglobulin A (IgA) production in preweaning immunocompetent mice nursed by immunodeficient dams. Here, we show that this enhancement of IgA in neonates results from maternally derived microbiota. In addition, we have found that the neonatal IgA production can be induced by Lactobacillus reuteri, which is enriched in the milk of immunodeficient dams. Moreover, we show that while the production of neonatal IgA is dependent on neonatal T cells, the immunodeficient maternal microbiota-mediated enhancement of neonatal IgA has a T cell– independent component. Indeed, this enhancement may be dependent on type 3 innate lymphoid cells in the neonatal small intestinal lamina propria. Interestingly, maternal microbiotainduced neonatal IgA does not cross-react with common enteric pathogens. Future investigations will determine the functional consequences of having this extra IgA.
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    Selective Histone Deacetylase 6 Inhibition Normalizes B Cell Activation and Germinal Center Formation in a Model of Systemic Lupus Erythematosus
    Ren, Jingjing; Catalina, Michelle D.; Eden, Kristin; Liao, Xiaofeng; Read, Kaitlin A.; Luo, Xin M.; McMillan, Ryan P.; Hulver, Matthew W.; Jarpe, Matthew; Bachali, Prathyusha; Grammer, Amrie C.; Lipsky, Peter E.; Reilly, Christopher M. (2019-10-25)
    Autoantibody production by plasma cells (PCs) plays a pivotal role in the pathogenesis of systemic lupus erythematosus (SLE). The molecular pathways by which B cells become pathogenic PC secreting autoantibodies in SLE are incompletely characterized. Histone deactylase 6 (HDAC6) is a unique cytoplasmic HDAC that modifies the interaction of a number of tubulin- associated proteins; inhibition of HDAC6 has been shown to be beneficial in murine models of SLE, but the downstream pathways accounting for the therapeutic benefit have not been clearly delineated. In the current study, we sought to determine whether selective HDAC6 inhibition would abrogate abnormal B cell activation in SLE. We treated NZB/W lupus mice with the selective HDAC6 inhibitor, ACY-738, for 4 weeks beginning at 20 weeks-of age. After only 4 weeks of treatment, manifestation of lupus nephritis (LN) were greatly reduced in these animals. We then used RNAseq to determine the genomic signatures of splenocytes from treated and untreated mice and applied computational cellular and pathway analysis to reveal multiple signaling events associated with B cell activation and differentiation in SLE that were modulated by HDAC6 inhibition. PC development was abrogated and germinal center (GC) formation was greatly reduced. When the HDAC6 inhibitor-treated lupus mouse gene signatures were compared to human lupus patient gene signatures, the results showed numerous immune, and inflammatory pathways increased in active human lupus were significantly decreased in the HDAC6 inhibitor treated animals. Pathway analysis suggested alterations in cellular metabolism might contribute to the normalization of lupus mouse spleen genomic signatures, and this was confirmed by direct measurement of the impact of the HDAC6 inhibitor on metabolic activities of murine spleen cells. Taken together, these studies show HDAC6 inhibition decreases B cell activation signaling pathways and reduces PC differentiation in SLE and suggest that a critical event might be modulation of cellular metabolism.