bluuebunny/crossref_metadata_2025_split huggingface dataset:
Clearance of skin-homing CCR7+ neutrophils by conventional type1 dendritic cells regulates cutaneous local autoimmunity and infection
Authors: Kolios Antonios , Diaz Victor , Egholm Cecilie , Halin Cornelia , Boyman Onur , Özcan Alaz 
Published: February 2023

Abstract
A rapid neutrophil response is essential for immunity against infections, however impaired elimination or migration can inflict significant tissue damage by exacerbated inflammation. Here we show that neutrophils recruited to inflamed or infected skin are rapidly redirected to skin-draining lymph nodes (dLNs) and non-draining secondary lymphoid tissues. Using transgenic mouse models and bone marrow chimeras, cutaneous inflammation is induced with imiquimod, a TLR7-mediated psoriasis-like model, or skin infection is induced by Staphylococcus aureus. We show that neutrophils migrate to the dLNs through lymphatic vessels in a CC-motif chemokine receptor 7 (CCR7)-dependent manner and are phagocytosed by resident conventional type1 dendritic cells in the dLNs when entering the lymph node, a mechanism contributing to neutrophil clearance. Deficiency of CCR7 impairs neutrophil elimination in the dLNs and leads to neutrophilic accumulation in the skin, which in turn leads to an exacerbated phenotype in a model of psoriasis-like local inflammation as well as improved clearance and immunity against cutaneous Staphylococcus aureus infection. Overall, our findings explain how impaired neutrophil migration and clearance in the dLNs could regulate cutaneous autoimmunity and infection.
TLR9 modulates peritoneal immunity via regulating the biology of CD9hi fibroblastic reticular cells
Authors: Jiang Ting , Li Yiming , Chen Tianmeng , Wu Junru , Chen Kong , Billiar Timothy R , Deng Meihong 
Published: February 2023

Abstract
Fibroblastic reticular cells (FRC) are highly heterogeneous. Distinct FRC subsets play unique roles in the formation of secondary lymphoid organs and immune responses. We have previously shown that TLR9 signaling plays a critical role in regulating peritoneal immunity via suppressing chemokine production in FRC in the fat associated lymphoid clusters (FALC). However, the subset-specific roles of TLR9 in FRC of FALCs remain unknown. Using single-cell RNA-sequencing, we identified three distinct subsets of FRC (CD55hi, CD9hi and CD55loCD9lo) in mouse mesenteric FALCs at baseline. Based on the gene set enrichment analysis, the Cd55hi subset was enriched in gene expression related to cell differentiation. The CD9hi subset was enriched in gene expression related to immune response. The CD55loCD9lo subset was enriched in the gene expression related to extracellular matrix formation. Furthermore, we found that CD9hi FRC from Tlr9−/− mice increased gene expression associated with inflammation. Using flow cytometry and bulk-RNA seq, we successfully isolated and validated these three subsets in mouse FALCs. Interestingly, activation of TLR9 signaling using ODN1585 significantly decreased CD9 expression in FRC in vivo and in vitro. Furthermore, treatment of ODN1585 suppressed the proliferation of CD9hi FRC, evidenced by decreased expression of Ki67. These results indicate that CD9hi FRC in FALC are immunoregulatory. TLR9 signaling may modulate peritoneal immunity via regulation of the proliferation of CD9hi FRC. Understanding the mechanism of how TLR9 regulates CD9hi FRC may lead to discovering new therapies for inflammatory diseases.
T-box transcription factors Eomes and T-bet regulate primary human NK cell IFNγ response and in vivo persistence
Authors: Wong Pamela , Chang Lily , Neal Carly C , Wagner Julia A , Berrien-Elliott Melissa M , Cubitt Celia C , Tran Jennifer , Marsala Lynne , Schappe Timothy , Fehniger Todd A 
Published: February 2023

Abstract
T-box transcription factors (TF) Eomes and T-bet are vital for NK cell development. However, their role in mature NK cell homeostasis and function remains unclear. Recently we reported that Eomes regulates mouse NK cell cytotoxicity and stage-specific survival using an NK-specific, tamoxifen-inducible Eomes KO model. However, the role of Eomes and T-bet have not been investigated in primary human NK (hNK) cell biology using genetic loss-of-function approaches. We hypothesized that these TFs play a critical role in maintaining NK cell functional molecular programs.
Here we used CRISPR-Cas9 to genetically delete Eomes and T-bet expression in primary hNK cells. In vitro stimulation assays revealed that IFNγ response is impaired in CD56bright NK cells only when Eomes is deleted (p&lt;0.01) but not T-bet. This impairment is even more striking when both TFs are deleted, resulting in both CD56bright and CD56dim NK cells having reduced IFNγ (p&lt;0.01 and p&lt;0.05, respectively).
Using NSG xenografts, we found that Eomes/T-bet double CRISPR-edited (DKO) hNK cells have impaired persistence/expansion in vivo. After 3 weeks, we recovered in the spleen on average 3E5 control compared to only 6E4 DKO hNK cells. A similar ~80% decrease was also observed in the blood. To determine the mechanism of this, we assessed proliferation and apoptosis of control compared to DKO cells. Ki-67 and dye dilution revealed impaired proliferation of DKO cells in vivo, and we also observed increased apoptosis measured by Annexin V/7-AAD staining (p&lt;0.05).
Our data suggest that Eomes and T-bet are critical for the function and homeostasis of mature hNK cells. Understanding their function in mature NK cells will provide insights to improve NK cell therapy for diseases such as cancer.
Multiplexed proteomics of autophagy deficient macrophages reveals enhanced anti-microbial immunity via the oxidative stress response
Authors: Maculins Timurs , Verschueren Erik , Hinkle Trent , Chang Patrick , Chalouni Cecile , Lim Junghyun , Katakam Anand Kumar , Kunz Ryan C. , Erickson Brian K , Huang Ting , Choi Meena , Tsai Tsung-Heng , Vitek Olga , Reichelt Mike , Rohde John , Dikic Ivan , Kirkpatrick Donald S. , Murthy Aditya 
Published: February 2023

Abstract
Macrophages play a critical role in clearance of cytosolic pathogens. Autophagy functions at the intersection of antimicrobial innate immunity, metabolism and protein quality control; however, the impacts of infection and autophagy on shaping the macrophage proteome are poorly understood. Here, we describe a deep multi-dimensional proteomic analysis of primary murine macrophages infected with Shigella flexneri (S. flexneri). Tandem mass tagging (TMT) revealed dynamic genotype- and infection-dependent differences in host and pathogen proteins, phosphorylation and ubiquitination. These data catalogue the complex circuitry connecting autophagy, inflammatory signaling and the oxidative stress response. Loss of the autophagy gene Atg16l1 induced basal oxidative stress, activated the compensatory glutathione biosynthetic machinery, and surprisingly, enhanced clearance of S. flexneri. Pathogen clearance was similarly enhanced in wild type macrophages upon pharmacological inhibition of cysteine import. Our study provides a resource for innate immunity research and unexpectedly reveals that ATG16L1 dampens antimicrobial immunity by regulating oxidative stress.
The effect of lipopolysaccharide (LPS) on post-viral airway disease is independent of the Type I interferon receptor
Authors: Resiliac Jenny , Rohlfing Michelle , Santoro Jennifer , Hussain Syed-Rehan A. , Grayson Mitchell 
Published: February 2023

Abstract

Rationale
Sendai virus (SeV, murine parainfluenza virus type 1) infection of C57BL6 (WT) mice leads to post-viral airway disease, characterized by airway hyperreactivity (AHR). Previous data suggested pretreatment of WT mice with lipopolysaccharide (LPS) decreased post-viral airway disease in a dose dependent manner. LPS binding to its receptor can trigger release of type I interferon (IFN), which is a critical anti-viral cytokine. Type I IFN is known to restrict viral replication and spread. However, the role type I IFN mediates in LPS protection from post-viral airway disease is not known. This study was undertaken to determine if the LPS mediated reduction of AHR depended upon type I IFN signaling.

Methods
WT and Ifnar−/− mice (mice with genetic deletion of the type I IFN receptor) were inoculated intranasally with 30 ul 0.1 μg LPS (dose that inhibited post-viral disease in prior studies) or PBS 24 hours before SeV (2e5 pfu) or UV inactivated SeV. Twenty-one days post-viral inoculation, AHR was determined by invasive measurement of airways’ resistance to methacholine.

Results
SeV induced a similar level of AHR in both Ifnar−/−and WT mice when they were pretreated with PBS. Similarly, pretreatment of Ifnar−/− mice with LPS significantly reduced AHR compared to PBS treated Ifnar−/− mice (p&lt;0.0001, ANOVA, n≥3). LPS treated Ifnar−/− mice demonstrated significantly reduced AHR compared to PBS treated WT mice, as well (p=0.001, n≥3).

Conclusion
LPS mediated reduction of post-viral airway disease is independent of type I IFN receptor signaling. Our results suggest LPS prevents post-viral AHR independent of IFNAR signaling. Future studies will determine other mechanisms through which LPS pre-treatment prevents post-viral AHR.
IFNβ is a critical regulator of Lyme arthritis severity in mice and is regulated by the tumor suppressor gene Cdkn2a on murine Chr4
Authors: Li Jinze , Ma Ying , Paquette Jackie K. , Zachary James F. , Teuscher Cory , Weis Janis J. 
Published: February 2023

Abstract
Lyme disease is caused by infection with the tick-borne spirochete Borrelia burgdorferi, and results in a spectrum of clinical disorders. Infected C3H mice develop severe Lyme arthritis while B6 mice display mild disease, allowing analysis of host genetic contribution to disease. We used forward genetics to identify a region on Chr4, Bbaa1, that includes the Type I IFN cluster and regulates arthritis severity. The development of congenic mice, B6.C3-Bbaa1, isolating the C3H allele of Bbaa1 onto the background of B6 mice demonstrated that Bbaa1 regulates arthritis severity by modulating Type I IFN expression. IFNβ was identified as the key effector for Lyme arthritis severity, however, paradoxically there are no polymorphisms between C3H and B6 in this gene. To identify regulators of IFNβ in the Bbaa1 locus, candidate genes were subjected to siRNA silencing. A single gene, Cdkn2a, was identified as the modulator of IFNβ expression, and its encoded protein ARF was found to regulate the magnitude of IFNβ expression. Reconstitution of Arf−/− mice with hematopoietic cells expressing the C3H allele of Arf developed severe arthritis, whereas mice reconstituted with cells expressing the B6 Arf allele developed mild arthritis. ARF was found to regulate B. burgdorferi induced IFNβ through p53 and BCL6 in myeloid cells. Indeed, targeted blocking of BCL6 enhanced IFNβ activation in the joint tissue of B6 mice and resulted in increased severity of Lyme arthritis. Results were similar in Rag-1-deficient mice, indicating dependence on myeloid cells expression of BCL6. Thus, we have identified novel pathways modulating IFNβ expression in Lyme arthritis development which could lead to therapeutic discovery.
Tpl2 Signaling Regulates Dendritic Cell Activation and Responding T Cell Differentiation Following Mycobacterium tuberculosis Infection
Authors: Groft Sarah Grace , Suzart Vinicius , Nagy Nancy , Boom W Henry , Harding Clifford V 
Published: February 2023

Abstract
Mycobacterium tuberculosis (Mtb) utilizes a number of immune evasion mechanisms in order to persist inside of host antigen-presenting cells. Dendritic cells (DCs) are important in restricting Mtb growth by migrating to draining lymph nodes and activating antigen-specific T cell responses, but the roles of DCs in Mtb infection require further study. This study investigated DC activation and functional outcomes following Mtb H37Ra-driven tumor progression locus 2 (Tpl2) signaling. The role of Tpl2 was interrogated genetically, utilizing bone marrow-derived DCs from Tpl2−/− mice. We assessed cytokine production via ELISA, mRNA levels via qRT-PCR, and expression of cell surface molecules via flow cytometry. In Mtb-treated DCs, genetic depletion of Tpl2 increased production of pro-inflammatory cytokines such as IL-12p40 and IL-6. Loss of Tpl2 in Mtb-treated DCs also led to decreased E-cadherin expression, and increased expression of Icam-1 (Cd54) and Mmp2, which are molecules involved in DC transmigration. Expression of Ccr7 and Ccr4 was also enhanced in Mtb-treated Tpl2−/− DCs, which correlated with improved migration of Tpl2−/− DCs towards CCL19 and CCL21 in vitro (assessed using a trans-well assay). When antigen-specific CD4+ T cells were co-cultured with Mtb-infected DCs, deletion of Tpl2−/− in the DCs resulted in increased T cell production of IFNγ and IL-2, as well as increased Tbet expression, indicative of enhanced Th1 polarization. Together, these data indicate that Mtb-induced Tpl2 signaling suppresses certain aspects of DC activation, leading to blunted Th1 responses against the pathogen.
Enhanced responsiveness to subsequent bacterial infection in macrophages stimulated with conserved protein patterns
Authors: Luu Abby , Shepardson Kelly , Hatton Alexis Alexandria , Robinson Ema , Goodall Cheri , Elkins Morgan , Douglas Trevor , Rynda-Apple Agnieszka 
Published: February 2023

Abstract
Immune modulation via exposure to a primary stimulus can modify innate immune cell responses to a subsequent unrelated infection. Previously, we found that conserved mammalian proteins which display a pattern of repeating protein subunits (RPSP) enhance clearance of a secondary respiratory bacterial infection in a TLR2/1-dependent manner. RPSPs like filamentous actin or ferritin are expressed intracellularly in a steady-state, thus their detection by extracellular pattern recognition receptors should elicit danger-like signals. Unlike classical DAMPs, which prompt an inflammatory response, TLR2/1-based recognition of RPSPs did not result in proinflammatory cytokine production or neutrophil lung infiltration. Yet, upon challenge with Staphylococcus aureus, RPSP inoculated mice exhibited a more robust inflammatory response and better bacterial clearance than control mice. This TLR2/1-based RPSP recognition was not limited to mammalian proteins. Enhanced S. aureus clearance was achieved with a synthetic peptide (Q11; QQKFQFQFEQQ) that organizes into RPSP fibers and is non-immunogenic. Further, we found that RPSP enhanced S. aureus clearance was dependent on non-classical Type I IFN signaling whereby IFNβ production was required, but absence of the IFNAR1 subunit of the Type I IFN receptor did not abrogate S. aureus clearance. In vivo depletion and bacterial clearance assays showed that macrophages were essential for this subsequent improved response, which persisted after resting cells for days post RPSP stimulation. Our results indicate that RPSP stimulation of macrophages enhances these cell’s abilities to respond to a secondary infection in an IFNβ dependent manner and has features suggestive of trained immunity.
Loss of myeloid S1PR1 makes dysfunctional alveolar macrophages and vascular injury by inducing myeloid bias
Authors: Banerjee Somenath , Joshi Jagdish C , Yalagala Vijayalakshmi , Mehta Dolly 
Published: February 2023

Abstract
Alveolar macrophages (AM) are the most abundant resident innate immune cells in the lungs and directly communicate with both the non-sterile external environment and the pulmonary epithelium. AM initially trigger protective inflammation upon sensing pathogen but later induce lung repair by clearing dead cells, known as efferocytosis, and dampening of inflammation. Studies show that monocytes recruited in the airspace during injury gain AM signature and contribute in lung repair. Sphingosine 1 phosphate receptor 1 (S1PR1), is widely studied in lung endothelium as a barrier protective mechanism and in immune cells in context of trafficking and inflammation but has not yet extensively studied in respect to origin and function of AM. Here, we deleted S1PR1 in mice by crossing S1PR1f/f with LysMCre (S1PR1ΔLyz) mice to investigate the role of S1PR1 in myeloid cells in the mechanism of lung injury. We show that loss of S1PR1 in myeloid cells of mice (S1PR1ΔLyz mice) has 3-fold higher AM pool but surprisingly these mice showed defective lung fluid balance basally or post LPS challenge (intratracheal 0.5 mg/kg). We found that S1PR1−/−AM produced markedly less pro-inflammatory cytokines (IL1b and TNFa) and could not efferocytose. Intriguingly, S1PR1 deficiency induced myeloid biased haematopoiesis as evident from less erythroid progenitor (~0.75 fold) and B cells (~0.82 fold) in bone marrow of S1PR1ΔLyz mice leading to increased circulating monocytes. panRNAseq of S1PR1−/− AM showed markedly reduced Sphk1 and NFκB1 expression and increased expression of KLF4, Myb, Myc, TLR7 & 8. These findings indicate that loss of S1PR1 misfires the generation of incompetent monocytes leading to dysfunctional AM and defective lung repair.
Innate Immune Memory in Lung Alveolar Macrophages Promotes Resilience and a Pro-Resolving Phenotype
Authors: Chakraborty Sreeparna , Singh Abhalaxmi , Maienschein-Cline Mark , Mukhopadhyay Amitabha , Rehman Jalees , Malik Asrar B. 
Published: February 2023

Abstract
Immune memory has been well-established in adaptive immunity but recent studies suggest a key for memory in innate immunity. However, the precise mechanisms and phenotypes of innate immune memory in macrophages remain poorly understood. Here, we studied the memory responses of lung alveolar macrophages (AMs) exposed consecutively (2 exposures, one week apart) intratracheally to the bacterial endotoxin lipopolysaccharide (LPS). We observed a 60%–80% loss of AMs following the initial LPS exposure, consistent with the known cell death of resident AMs during severe inflammatory injury followed by gradual replenishment. Importantly, AM loss following the second LPS injury was markedly attenuated. Lineage tracing using a CX3CR1-monocyte reporter showed no increase in monocyte-derived AMs, thus suggesting that the higher AM numbers after the second LPS exposure were due to greater resilience of AMs and not due to rapid replenishment by circulating monocytes. RNA-Seq analysis of showed higher expression of pro-survival genes and anti-inflammatory cytokines such as IL-10 in memory AMs (post 1 week LPS) than in naïve AMs. Ex vivo and in vivo functional assay showed that these memory AMs demonstrated enhanced efferocytosis of cellular debris, consistent with a pro-resolving phenotype. We also found upregulation of the transcription factor KLF4 which promotes cell survival as well as pro-resolving macrophage polarization. Our findings suggest that alveolar macrophages are reprogrammed by an initial inflammatory exposure to increase their resilience to pro-apoptotic stimuli and to promote resolution of inflammation. Such a memory mechanism could be leveraged therapeutically in severe inflammatory diseases.
Ethanol suppresses the pulmonary response to Streptococcus pneumoniae: Role of NOD2 and NF-kB signaling in alveolar macrophages exposed to muramyl dipeptide.
Authors: Hulsebus Holly J , Najarro Kevin M , McMahan Rachel H , Kovacs Elizabeth J 
Published: February 2023

Abstract
Alcohol use decreases host immune defense and increases susceptibility to pathogens such as Streptococcus pneumoniae. NOD2 is an intracellular pattern recognition receptor that binds muramyl dipeptide (MDP), a cell wall component of S. pneumoniae, and activates NF-kB signaling. To limit inflammation, NF-kB signaling is negatively regulated in part by TNFAIP3 (TNF Alpha Induced Protein 3), or A20. We hypothesize that ethanol impairs NOD2 signaling and A20 expression in alveolar macrophages, leading to excessive inflammation and reduced bacterial clearance after infection. For in vivo experiments, we gavaged mice once daily for 3 consecutive days with water or ethanol (blood alcohol concentration ~ 80 mg/dL at 30 min), and infected with 104 cfu S. pneumoniae. In parallel experiments, MH-S cells were treated with 25 mM ethanol and 10 μg/ml MDP. We found that ethanol treated animals, compared to vehicle treated, had impaired respiratory function (17% lowered respiration rate [p &lt; 0.01] and 33% increased penh [p = 0.09]) and increased lung bacteria (log10 increase of 0.8 [p = 0.11]) at 24 hours. RNA sequencing of alveolar macrophages from vehicle- or ethanol-gavaged mice revealed that ethanol intake led to 25% less Nod2 and 60% less A20 (p &lt; 0.05) in the absence of infection. These results were confirmed by qPCR in ethanol-treated MH-S cells (40% decrease in Nod2 and 50% reduction in A20 [p &lt; 0.01]), along with 15% lower A20 protein levels, which was sustained after MDP stimulation (29% less A20 compared to vehicle-treated, stimulated cells). Future experiments aim to further investigate ethanol’s effect on A20 regulation of NF-kB signaling, and will provide insight into immune dysregulation seen in alcohol-consuming patients with pneumonia.
Thymic Stromal Lymphopoietin induces adipose loss through sebum hypersecretion
Authors: Choa Ruth , Tohyama Junichiro , Wada Shogo , Meng Hu , Okumura Mariko , May Rebecca , Robertson Tanner , Pai Ruth-Anne , Nace Arben , Hopkins Christian , Jacobsen Elizabeth , Haldar Malay , FitzGerald Garret , Behrens Edward , Minn Andy , Seale Patrick , Cotsarelis George , Kim Brian , Seykora John , Arany Zoltan , Kambayashi Taku 
Published: February 2023

Abstract
Obesity is a serious public health concern. Emerging studies indicate that the immune system can regulate weight and energy homeostasis. Here we show that the cytokine Thymic Stromal Lymphopoietin (TSLP) stimulates T cells to induce selective white adipose loss, which protects against obesity, improves glucose metabolism, and mitigates nonalcoholic steatohepatitis. Surprisingly, adipose loss was not caused by alterations in food intake, absorption, or energy expenditure. Rather, it was caused by the excessive loss of lipids through the skin as sebum, causing mice to develop a striking “greasy hair” phenotype. Inhibition of sebum secretion or depletion of T cells prevented TSLP-driven adipose loss. TSLP-driven white fat loss and sebum hypersecretion were both mediated via the direct activation of CD4+ or CD8+ T cells by TSLP in an antigen-independent manner, and these T cells could be seen infiltrating skin sebaceous glands. Furthermore, we also found that TSLP and T cells regulated sebum release and sebum-associated anti-microbial peptide expression in the skin at steady-state. In human skin, TSLP expression also correlated directly with sebum-associated gene expression. Together, our study establishes a paradigm in which adipose loss can be achieved by sebum hypersecretion and reveals a previously unknown role of adaptive immunity in skin barrier function through the regulation of sebum secretion.