bluuebunny/crossref_metadata_2025_split huggingface dataset:
Targeted gastrointestinal tract homing of regulatory T-cells reduces acute graft-versus-host disease severity by simulating an increase in Treg dose in vivo
Authors: Nicholls Jemma H , Loschi Michael , Jin Sujeong , Wagers Sara Bolivar , Thangavelu Govindarajan , Zaiken Michael C , McDonald-Hyman Cameron , Saha Asim , Aguliar Ethan G , Koehn Brent , Osborn Mark J , MacDonald Kelli P.A. , Kim Sangwon V , Littman Dan R , Blazar Bruce R 
Published: February 2023

Abstract
Damage to the gastrointestinal (GI) tract following hematopoietic stem cell transplant (HSCT) has been shown to drive the development of acute graft-versus-host disease (aGVHD). We have demonstrated clinically that infusing regulatory T-cells (Treg) during HSCT reduces aGVHD risk while supporting immune recovery; however, high Treg doses were necessary. Here we demonstrate that by promoting Treg homing to the GI tract early post-HSCT, aGVHD severity was reduced. Ex vivo expanded murine Treg were retrovirally transduced to overexpress the orphan chemoattractant receptor GPR15 for colon specific T-cell homing. Despite no change in Treg phenotype or in vitro suppressive function when administered to HSCT recipient mice at the time of transplantation, mice that received GPR15+ Treg exhibited significantly reduced aGVHD severity and prolonged survival compared to control Treg mice (p = 0.0035). To confirm that this resulted from an increased Treg accumulation in the GI tissues, we then assessed the frequency and retention of GPR15+ Treg in mice post-HSCT by in vivo and ex vivo bioluminescent imaging as well as flow analysis. From these data, we observed not only superior localization of GPR15+ Treg within GI tissues, but also significantly reduced inflammation and tissue damage in GPR15+ Treg recipient mice early post-HSCT. Our data provides evidence that deliberate targeting of ex vivo expanded Treg to the GI tract during HSCT significantly reduces injury to the GI tract and reduces aGVHD severity by simulating an increase in Treg dose in vivo. These data provide a rational for the future development of clinical Treg products for increased control of GI aGVHD following HSCT.
Integrin α4β1-dependent regulatory B-cell migration into the skin limits cutaneous inflammation
Authors: Diaz Lazaro Emilio Aira , Debes Gudrun Fiona 
Published: February 2023

Abstract
B cells continuously recirculate through the skin. However, their localized functions within the cutaneous environment are still largely unknown. A subset of IL-10+ B regulatory cells (Bregs) migrate into inflamed skin in an α4β1-integrin-dependent manner, thus we hypothesize that an impaired skin-migration of these Bregs could aggravate skin inflammation. Using two types of skin inflammation (IMQ-induced psoriasiform and DNFB-mediated delayed contact hypersensitivity) in a mouse model with a B cell-specific inducible deletion of α4β1-integrin, we found that loss of α4β1-integrin expression in B cells led to a significant decrease in the numbers of IL-10+ B cells in the inflamed skin without affecting their numbers in lymphoid tissues. The reduced homing of Bregs into the inflamed skin was associated with a significant increase in the clinical and histopathological parameters of cutaneous inflammation in both mouse models. Additionally, transfer of IL-10 competent B cells into Bregs-deficient mice lead to a significant improvement in the psoriasiform skin phenotype. Thus, our data show a key role for skin-homing IL-10+ Bregs in the suppression of skin inflammation, supporting the notion that Bregs are critical players in the cutaneous environment during inflammatory skin diseases.
Syndecan-1 modulates plasma cell motility and competition within the bone marrow
Authors: Benet Zachary , Fooksman David R 
Published: February 2023

Abstract
Plasma cells (PC) are terminally differentiated B cells that secrete antibodies. PCs residing in the bone marrow (BM) express high levels of Syndecan-1 (Sdc1), and we have shown expression promotes PC maturation and survival in a cell intrinsic manner. Sdc1 may also mediate integrin activation and contribute to cell motility and adhesion, which may contribute to PC retention and survival. However, as PCs express heterogenous levels of Sdc1, it is unknown whether the amount of Sdc1 surface expression directly contributes to their overall fitness. Therefore, we assessed the fitness of PCs with altered Sdc1 expression within the BM.
Using co-transfers of WT and Sdc1+/− donor B cells, we tracked PC responses following immunization within both WT and Sdc1+/− recipients. Donor-derived WT PCs expressed higher surface expression of Sdc1 than Sdc1+/− PCs, and WT PCs were present at higher frequencies than those derived from Sdc1+/− donors within the BM but similar within spleen. Interestingly, in Sdc1+/− recipients, there were similar frequencies of donor-derived WT and Sdc1+/− PCs suggesting reduced PC competition based on endogenous Sdc1 levels. Sdc1 has been implicated in integrin activation and potentially affects cell motility thus we assessed PC dynamics of WT, Sdc1+/−, and Sdc1−/− using intravital microscopy. PCs were motile in all hosts, but speeds were proportional to Sdc1 genotype. We screened potential ligands of Sdc1-dependent integrin activation and found that WT but not Sdc1−/− PCs bound to and moved on fibronectin. Using in vitro live cell imaging, we found binding was mediated by Sdc1 through integrin recruitment or activation. These data suggest that PC fitness is driven by Sdc1 and correlates with enhanced PC motility within the BM.
Defining the role of Siglec-6-DOCK8 axis in cell adhesion and migration in Chronic Lymphocytic Leukemia
Authors: Nunes Jessica Judith , Ventura Ann , Hu Eileen , Zapolnik Kevan , Mo Xiaokui , Byrd John , Rader Christoph , Muthusamy Natarajan 
Published: February 2023

Abstract
Siglec-6 is a sialic acid-binding immunoglobulin-like lectin that is involved in diverse functions in trophoblasts. We recently identified expression of Siglec-6 on B cells from chronic lymphocytic leukemia (CLL) patients (B-CLL cells) but not normal donors. To determine the role of Siglec-6 in B-CLL cells, we used the CRISPR-Cas9 technique to knock-out (KO) Siglec-6 in a human CLL cell line, MEC1. We then evaluated the migratory role of Siglec-6+MEC1 cells towards sialyl-Tn (sTn), a known Siglec-6 ligand, or sTn+ CLL patient derived bone marrow stromal cells (BMSCs). Compared to Siglec-6+ MEC1 cells, Siglec-6− MEC1 cells exhibited significant reduction in adhesion to and migration towards sTn or sTn+ CLL-BMSCs in cell adhesion and trans-well migration assays. Interestingly, sTn is overexpressed on CLL-BMSCs compared to normal donor derived BMSCs. Importantly, a Siglec-6 targeted antibody inhibited homing of Siglec-6+ MEC1 cells to the spleen and bone marrow in NSG mice. Mass spectrometry and co-immunoprecipitation analysis in MEC1 cells revealed interaction of Siglec-6 with DOCK8, a guanine nucleotide exchange factor. Stimulation of Siglec-6+ MEC1 cells with sTn resulted in Cdc42 activation, a downstream target of DOCK8, and actin polymerization which was compromised in Siglec-6 or DOCK8 KO MEC1 cells. In summary our studies have identified a novel role for Siglec-6 and its ligand in CLL through promotion of Siglec-6 and DOCK8 dependent activation of Cdc42, actin polymerization, cell migration, and subsequent attachment of B-CLL cells to CLL-BMSCs. Ongoing studies are focused on molecular mechanisms of Siglec-6 mediated regulation of actin polymerization and CLL-BMSC interactions in cell migration and adhesion.
Modeling relationship of pharmacokinetics, in vitro potency, and α4β7 receptor occupancy with intestinal cell trafficking in a gut-homing mouse model of IBD with MORF-057
Authors: Redhu Naresh S. , Hussain Ali , Srinivasan Sathish , Lee Dooyoung , Bannister Brianna , Blanco Natalia , Bonesteel Raegan , Camblin Adam , Cappellucci Laura , Cohen Rhianna , Harrison Bryce , Hahn Kristopher N , Kim Kwangsoo , Krumpoch Megan , Lin Fu-Yang , McManus Kevin , McShea Molly , Pondish Jessica , Linde Peter , Lugovskoy Alex , Mangada Maloy , Moy Terence I. , Sang Allison , Gelais Sarah St. , Sullivan Andrew , Troast Dawn , Zhong Cheng , Wang Liangsu , Cui Dan , Bursavich Matthew G. , Lippa Blaise , Rogers Bruce N. , Ray Adrian S. , Wong Jamie 
Published: February 2023

Abstract

Objective:
MORF-057 is an orally bioavailable, selective, and potent small molecule inhibitor of α4β7 integrin being developed for inflammatory bowel diseases (IBD) that is currently in phase 1 clinical testing. We have previously presented work that characterized its nonclinical pharmacologic profile. The current study integrates data to generate a pharmacokinetic (PK) and pharmacodynamic (PD) model of MORF-057.

Methods:
To determine in vivo potency, MORF-057 was tested in murine gut homing assays and the PD response was determined relative to the non-protein bound drug in mouse plasma. A cell adhesion assay (CAA) for α4β7 was refined to enable detection of picomolar-level sensitivity. Murine receptor occupancy (RO) assays for α4β7 and α4β1 were established under physiologic conditions, and MORF-057 was evaluated for its potency and selectivity in fresh mouse whole blood. These datasets were used to build and validate predictive models of PD response.

Results:
MORF-057 strongly inhibited the homing of α4β7hi cells to murine gut lymphoid tissues with an IC90 of 7.9 nM. MORF-057 showed high potency in CAA with an IC90 of 8.8 nM. Similarly, RO assays confirmed MORF-057 to be a highly potent inhibitor of α4β7 in mouse whole blood with an IC90 of 20.5 nM and over 1500-fold selectivity vs. α4β1. The predictive models built upon these datasets revealed a strong PK-PD relationship of α4β7 inhibitors in vivo.

Conclusions:
We observed consistently high potency of MORF-057 across multiple assay platforms. Integrated modeling based on these assays, particularly the RO assay, successfully predicted the PD response to MORF-057. These data begin to establish the relationship between PK, target engagement, and PD with MORF-057.
Macrophage polarization in obesity induced inflammation: The effect of HSP70
Authors: Botros Fady , Pytynia Matt , Kohlmeir Ellen , Incrocci Ryan , Swartzendruber Julie A , Evans Christian , Ciancio Mae J 
Published: February 2023

Abstract
Obesity is a chronic inflammatory disease that plagues our nation’s healthcare system. Tissue macrophages and recruited monocytes are implicated in the systemic release of pro-inflammatory cytokines that foster disease progression. Diet-induced obesity (DIO) is prevented in heat shock protein 70 over-expressing (HSP70 transgenic; TG) mice. While there are several mechanisms responsible for this protective response, prevention of macrophage polarization to a pro-inflammatory phenotype (M1) may be one contributory mechanism that warrants further investigation. Using a TG mouse line with selective over-expression of HSP70 in villin-expressing epithelial cells, male TG and non-transgenic (NTG) littermates were fed a low fat (LF; 10 kcal% fat) or high fat (HF; 60 kcal% fat) diet for 13 weeks (Research Diets, Inc). Peritoneal cavity macrophages were harvested from these mice and analyzed by flow cytometry (Beckman Coulter Cytoflex) using the following markers: total (F4/80 APC), M1 (CD38 PE), and M2 (CD301 APC/Fire 750) macrophages. TG mice demonstrated increased F4/80+high macrophages and more F4/80+high M2 cells in comparison to their NTG littermates (p=0.051). These results demonstrate HSP70 over-expression in vivo increases the population of macrophages, particularly anti-inflammatory M2 macrophages, in the peritoneal cavity. Preferential M2 phenotype could be a significant contributory factor to HSP70-mediated protection from DIO.
S100A9 modulates neutrophil extracellular trap formation thereby enhancing macrophage killing of bacterial pathogens.
Authors: Monteith Andrew J , Miller Jeanette M , Maxwell C Noel , Chazin Walter J , Skaar Eric P 
Published: February 2023

Abstract
Professional phagocytes form the backbone of the innate immune response and are equipped with an arsenal of antimicrobial processes. While many of these processes have been explored in isolation, how immune cells cooperatively combat bacterial pathogens at the site of infection is unclear. The proteins forming calprotectin, S100A8 and S100A9, are the most abundant cytosolic proteins in neutrophils and important components of the innate immune response. Surprisingly, S100A9-deficient (A9−/−) mice are protected from Staphylococcus aureus infection with lower bacterial burdens in the heart. We have uncovered an intracellular function for S100A9, where A9−/− neutrophils produce more mitochondrial superoxide, thereby promoting the terminal formation of neutrophil extracellular traps (suicidal NETosis). Increased suicidal NETosis does not heighten neutrophil killing of S. aureus in isolation, but rather augments macrophage (Mϕ) killing. More specifically, NET formation enhances Mϕ antibacterial activity coinciding with Mϕ phagocytosis of S. aureus and transferring neutrophil-specific antimicrobial peptides to Mϕs. Finally, similar results are observed in response to other phylogenetically distinct bacterial pathogens implicating this as an immune defense mechanism that broadly enhances antibacterial activity. Based on these results, we propose that intracellular S100A9 is a critical rheostat for neutrophil function during infection. Further, NET formation acts as a conduit for neutrophils to enhance the antibacterial activity of Mϕs, where accelerated suicidal NETosis by A9−/− neutrophils makes them especially adept at increasing the antibacterial activity of Mϕs against multiple bacterial pathogens.
Essential Role of ZIP8 in myeloid-mediated host defense against pneumococcal pneumonia
Authors: Hall Sannette C , Smith Deandra R , Wyatt Todd A , Knoell Daren L 
Published: February 2023

Abstract
Zinc (Zn) is essential for proper immune function. Dietary deficiency increases susceptibility to bacterial infections, including Streptococcus pneumoniae, a leading cause of community acquired pneumonia. Zn homeostasis is tightly regulated by 24 Zn transporters. ZIP8, an importer, is rapidly upregulated in myeloid cells following bacterial infection and regulates immune function in a Zn-dependent manner. Knowing that myeloid cells (macrophages, neutrophils, and dendritic cells) play critical roles in host defense against S. pneumoniae, we hypothesized that ZIP8 loss would alter myeloid cell function and adversely impact the host response to pneumococcus.
Using a myeloid-specific Zip8-KO mouse model, we observed that intranasal instillation of S. pneumoniae resulted in increased inflammation, lung injury and mortality with 40% of Zip8-KO animals succumbing to infection by day 4. Based on this, the immune response between 24 and 72 hours post infection was further examined. Analysis of BAL fluid revealed a significant increase in macrophages in Zip8-KO animals and lung homogenates revealed a significant increase in total lung leukocytes, macrophages and inflammatory DCs. The increase in myeloid cell populations in Zip8-KO mice was also associated with bacterial extravasation as measured by increased bacterial burden in the spleen. Collectively, these results indicate that ZIP8 loss aggravates the immune response through alteration of the myeloid cell landscape and lung architecture in response to S. pneumoniae. Further studies are warranted to determine how ZIP8 loss drives myeloid dysfunction, tissue damage and pathogen dissemination and whether genetic deficits in ZIP8 function can be overcome by Zn supplementation.
Clearance of Plasmodium falciparum-infected Red Blood Cells by Natural Killer cells and Monocytes
Authors: Sekar Padmapriya , Arora Gunjan , Schureck Marc , Desai Sanjay , Long Eric O 
Published: February 2023

Abstract
Antibodies naturally acquired during repeated exposure to the parasite Plasmodium falciparum are essential for control of blood-stage malaria. Natural killer (NK) cells are innate immune cells with an important role in containing viral infections and tumor growth, mainly by direct cytotoxicity and inflammatory cytokine production. Recently, the lab reported that primary human NK cells lyse Plasmodium falciparum-infected red blood cells (iRBCs) via antibody dependent cellular cytotoxicity (ADCC) in presence of IgG isolated from adults living in a malaria-endemic region of Mali. Using live imaging, I observed release of parasitophorous vacuoles (PV) from iRBCs after incubation with NK cells in the presence of rabbit anti-RBC Abs. I confirmed the imaging results by flow cytometric analysis. Direct interactions of NK cells with iRBCs was imaged by scanning electron microscopy, which revealed tight immunological synapses and extensive damage to iRBC membranes. This membrane damage results in formation of ghost RBCs and eventually release of PVs. We hypothesized that monocytes clear PVs, which could reduce the inflammatory response. I isolated PVs by mild saponin treatment and mechanical disruption of iRBC membranes. Binding of IgG isolated from plasma of Malian adults to PVs was orders of magnitude higher than binding to iRBCs. Phagocytosis of PVs by primary human monocytes was detected and was enhanced in the presence of Mali IgG. Similar results were obtained using PVs released by NK-dependent lysis of iRBCs in the presence of Mali IgG. These results suggest that NK-mediated ADCC inflicts severe damage to the plasma membrane of iRBCs, leading to release of PVs which bind immune serum IgG and are cleared through phagocytosis by monocytes.
SARs-CoV-2 Infection Impacts the Function and Phenotype of Plasmacytoid Dendritic Cells
Authors: Codrington Alicia L , Dewald Hannah , Elson David , Chopoorian Abby , Zembrziglel Krzysztof , Park Claire , Singh Sukhwinder , Xie Yingda , Fitzgerald-Bocarsly Patricia 
Published: February 2023

Abstract
Plasmacytoid dendritic cells (pDC) are innate immune cells and potent producers of interferon alpha (IFN-α). Sars-CoV-2, an RNA virus that causes Coronavirus Disease 2019 (COVID-19), has taken the lives of more than 400,000 people in the United States. Reports indicate that COVID-19 patients have reduced plasma IFN-α, suggesting a potential use of IFN-α as a disease therapeutic. However, investigations on pDC function and phenotype in COVID-19 patients are needed. We isolated peripheral blood mononuclear cells from fifty hospitalized COVID-19 patients. PBMC were stimulated with HSV-1 or Influenza A virus and IFN-α production and phenotype were assessed by flow cytometry. After stimulation, there were fewer IFN-α+ pDC from COVID-19 patients compared to controls. To reduce inflammation, COVID-19 patients may be treated with dexamethasone, a corticosteroid that has negative effects on pDC function. Although there was more impairment of pDC numbers and function in dexamethasone-treated subjects, the pDC dysregulation was also seen prior to dexamethasone treatment. Phenotypically, we identified reduced expression of pDC markers BDCA2 and CD123, and an upregulation of co-stimulatory markers on pDC from COVID-19 patients. We also observed an increased proportion of Ki67+ pDCs, which indicates increased turnover of pDCs during moderate to severe COVID-19 disease. In summary, pDC from COVID-19 patients produce significantly less IFN-α, express costimulatory ligands used to stimulate adaptive immunity, and may be undergoing rapid turnover. Overall, these changes may compromise the antiviral and adaptive immune response or represent pDC exhaustion during SARS-CoV-2 infection.
NLRP3 inflammasome inhibitor as an adjunct host-directed therapy in a hyper susceptible mouse model of Group A Streptococcal Necrotizing Fasciitis.
Authors: Mukundan Santhosh , Satpati Abhijit , Ambigapathy Ganesh , Combs Colin , Nookala Suba 
Published: February 2023

Abstract
Despite prompt intervention with antibiotics and surgical debridement, morbidity and mortality due to Group A Streptococcal Necrotizing Fasciitis (GAS-NF), frequently associated with streptococcal toxic shock, remain as high as 50%. The pathways driving the sequelae of effector responses that include an uncoordinated activation of the host immune system and inflammatory cytokine storm are not completely elucidated. Our previous studies demonstrated a central role for the pro-inflammatory mediator, IL-1b, in modulating the severity and survival in a mouse model of GAS-NF. To fine-tune IL-1b levels while simultaneously attenuating GAS multiplication and toxin synthesis, here, we investigated the effect of MCC950 (MCC), a small molecule inhibitor for NLRP3 inflammasome activation as a host-directed adjunct to clindamycin (CLN) (10mg/kg each, everyday X 5 days) in a mouse model of GAS NF. Survival outcomes did not differ between CLN and CLNMCC groups. Yet, CLNMCC significantly reduced skin mRNA levels of IL-1a, IL-1b, IL-33, and TNF-a, protein levels of the active fragment of caspase-1 and increased the ratio of pro: active caspase-1 (but not ASC or NLRP3) that coincided with reduced levels of circulating neutrophils. CLNMCC treatment significantly reduced tissue damage, levels of plasma IL-10, IL-1β, and circulating CD11b+LY6G+ granulocytic myeloid subsets. These results indicate that NLRP3 inflammasome activation may be primarily involved in excess IL-1b release, neutrophil influx, and tissue damage during GAS-NF. The evidence of improved outcomes suggests, in part, a beneficial efficacy of MCC950 to target NLRP3 as a feasible adjunct to CLN and mitigate inflammation and pathology with no adverse effects or delayed toxicity
BCG vaccination provides cross-protection against influenza infection through trained adaptive immunity.
Authors: Tran Kim , Divangahi Maziar 
Published: February 2023

Abstract
The ongoing COVID-19 pandemic highlights the threat emerging viruses pose to the world. While the development of a new vaccine can take at least 1–2 years, alternative approaches are urgently needed to alleviate the burden of rapid transmission. The Bacillus Calmette-Guerin (BCG) vaccine is currently used worldwide to prevent tuberculosis but has also been shown to protect against a wide range of infections. Several studies have attributed this broad protection to trained immunity. While innate immune cells usually act in a non-specific manner, in the context of trained immunity, these cells acquire an enhanced capacity to protect against different pathogens. However, preliminary work suggests that BCG may be mediating trained immunity by enhancing the adaptive immune system as well. Before the current pandemic, Influenza A virus (IAV) was responsible for the most devastating pandemic in history and remains the cause of yearly epidemics. Thus, investigating the cross-protection of BCG against IAV could determine whether BCG vaccination could offer an alternative preventive strategy against viruses with pandemic potential. To determine the protective effects of BCG against IAV infection, C57BL/6 mice were vaccinated intravenously (-iv) or subcutaneously (-sc) with BCG then infected with H1N1. We showed that BCG-iv vaccinated mice exhibited increased survival against IAV and a decreased viral load. Interestingly, BCG-iv uniquely induces the enrichment of CX3CR1+ αβ memory T cell populations which may be contributing to protective immunity against IAV infection. Overall, the present study evaluates whether beneficial effects from a widely distributed vaccine could provide some protection against emerging pulmonary pathogens.