bluuebunny/crossref_metadata_2025_split huggingface dataset:
Opposing roles of tyrosine kinase receptors Mer and Axl determine clinical outcome in a mouse model of nephritis
Authors: Shao Wenhai , Zhen Yuxuan 
Published: January 2023

Abstract
Systemic lupus erythematosus (SLE) is an autoimmune disorder with unknown etiology. Lupus nephritis remains one of the most severe manifestations of SLE, with considerable morbidity and mortality. There remains a major void in the successful management of lupus nephritis. TAM (Tyro-3, Axl and Mer) receptor tyrosine kinases play an important role in the maintenance of immune homeostasis. Mer is constitutively highly expressed on glomerular endothelial cells; Axl expression is inducible in kidney under inflammatory conditions. To investigate the functions of Axl and Mer in lupus nephritis, we induced glomerulonephritis in WT, Axl-KO, Mer-KO, and A/M-KO (Axl/Mer-double knockout) mice by injection of nephrotoxic serum (NTS). Mer-KO mice developed severe glomerulonephritis, with significantly decreased survival rate and increased blood urea nitrogen (BUN) levels as compared to WT mice given the same treatment. Two weeks after injection, necrotic cell death was evident in the glomeruli of Mer-KO mice. However, Axl-KO presented with significantly increased survival rate and reduced BUN as compared to the WT, Mer-KO and A/M-KO mice injected with the same serum. Interestingly, the A/M-KO mice developed kidney inflammation comparable to WT mice. Western blot analysis revealed significantly increased Stat3 phosphorylation and caspase-1 activation in the kidney of Mer-KO mice after NTS injection. In contrast, Axl deficient NTS-injected mice developed decreased Akt phosphorylation and Bcl-xl upregulation. The reciprocal activation of Axl and Mer receptor tyrosine kinases may have a major impact on renal inflammation. Results from these studies may lead to novel therapeutic drug development targeted to lupus nephritis.
Endothelial Protein C Receptor regulates skin gamma delta T cell functions
Authors: Ramirez Kevin P , Witherden Deborah , Ruf Wolfram , Havran Wendy L 
Published: January 2023

Abstract
The molecular interactions controlling gamma delta (γδ) T cell functions remains poorly understood as these cells do not express many of the costimulatory receptors known to regulate alpha beta T cell activation. Dendritic epidermal T cells (DETC) are prototypic γδ cells that promote tissue homeostasis by producing keratinocyte survival factors under steady state conditions and locally releasing epithelial cell mitogens upon stimulation by skin wounding. Endothelial Protein C Receptor (EPCR) is an MHC class I-like molecule recently demonstrated to be a TCR ligand for a subset of human γδ T cells. In the skin, EPCR is expressed by keratinocytes and has been implicated in skin wound repair in vitro. We therefore hypothesized that DETC recognize and are functionally dependent on cutaneous EPCR expression. We show that mutant mice with reduced expression of EPCR display delayed repair of experimental skin wounds. This wounding phenotype is associated with reduced cellular markers of activation and defective production of inflammatory cytokines by DETC. Conversely, EPCR is highly upregulated in normal keratinocytes proximal to wound sites. EPCR may engage DETC directly as a subset of these cells express the known EPCR binding partner, CD11b, and wound proximal DETC appear to bind a soluble form of EPCR. Collectively, our data indicates that EPCR serves a costimulatory molecule for skin-resident γδ T cells.
Retinoic acid and IFNγ induce parallel Arg1 and Nos2 gene expression in primary mouse Kupffer cells.
Authors: Mohar Isaac , Crispe Ian Nicholas 
Published: January 2023

Abstract
Acute inflammation is associated with classically activated macrophages, while chronic inflammation is associated with fibrosis and alternatively activated (M2) macrophages. Liver fibrosis is a common complication of chronic liver inflammation, yet the molecular signals that promote M2 Kupffer cells, resident liver macrophages, are poorly defined. In the liver, activated hepatic stellate cells (HSC) are associated with fibrosis and release retinoic acid (RA). Here, we test the hypothesis that RA polarizes Kupffer cells to an M2 state. We contrast this to activation by IFNγ or lipopolysaccharide (LPS). Kupffer cells were isolated from C57BL/6J mice (N = 2–5) by sort-purification; plated at 30,000 per well for 24 hours; and then stimulated with 100 ng/mL LPS, 100 ng/mL IFNγ, 100 μM RA, or IFNγ + RA for 24 hours. Isolated RNA was analyzed by microfluidic qRT-PCR using assays for genes characteristic of macrophage activation. LPS induced Socs3, Ptgs2, Nos2, Tnf, Icam1, Il6, Il1a, Il10, and Marco. IFNγ induced Socs3, Ptgs2, Nos2, Tnf, Icam1, Ciita, Ccl12, and Klf4; and suppressed Mrc1. RA only induced expression of Arginase-1 (Arg1). Unexpectedly, co-treatment with RA and IFNγ induced additive expression. In summary, treatment of primary Kupffer cells with RA induces Arg1; co-treatment with IFNγ and RA simultaneously induces Arg1 and Nos2; and LPS, but not IFNγ, induces Il6 gene expression. These results support the hypothesis that HSC activation may induce aspects of alternative activation in Kupffer cells and demonstrate that classical and alternative activation fates of macrophages are not always mutually exclusive.
Understanding macrophage recruitment to the stressed airspaces
Authors: Saini Yogesh , Mohammad Owais , Lewis Brandon W. , Sultana Razia 
Published: January 2023

Abstract
The presence of functionally competent macrophages in respiratory airspaces is critical to the normal host immune responses. To determine the effect of altered macrophage (MΦ) populations on macrophage recruitment, we employed LysM+/mTOM\mEGFP+/DTA+ mice, a model of macrophage depletion and mEGFP+ labeling. Since controlled by same promoter (Lysozyme M; LysM) and separate alleles of ROSA locus, the expression of mEGFP and DTA transgenes is simultaneously induced that facilitates mEGFP+ fluorescent labeling of DTA+ cells with LysM+ activity. Flow cytometric and confocal microscopic analyses revealed the mEGFP+ labeling of entire bronchoalveolar lavage (BAL) MΦ populations in the LysM+/mTOM\mEGFP+/DTA- mice. However, the LysM+/mTOM\mEGFP+/DTA+ had a significant increase in the number of mTOM+ MΦ populations. We hypothesized that the mTOM+ population represents freshly recruited (immature) macrophages that are functionally and phenotypically differently than the mEGFP+ MΦ. The flow cytometric analyses and confocal microscopic approach to immunophenotype mTOM+ and mEGFP+ MΦ revealed increased mTOM+ cells in the DTA+ mice. The mTOM+ MΦ exhibited monocyte-like phenotype with surface expression of CD11b and CD11c whereas entire MΦ populations (~96% are mEGFP+) in the DTA- are CD11b- and CD11c+. The gene expression analysis of mTOM+ and mEGFP+ MΦ revealed significantly altered gene expression of genes for macrophage activation, surface receptors, protease, and anti-proteases. Collectively, our approach and data collected highlights the importance of studying the mature and immature (freshly recruited) macrophage populations independently.
Local Complement production and TLR crosstalk in intestinal ischemia/reperfusion
Authors: Fleming Sherry D , Pope Michael 
Published: January 2023

Abstract
Intestinal ischemia/reperfusion (IR)-induced tissue damage requires crosstalk between complement components and toll-like receptors (TLR). TLR2 and TLR4 are expressed on both white blood cells and intestinal epithelial cells. In addition, complement may be produced in the local tissue as well as in the liver. We hypothesized that expression of TLRs would induce local production of complement components by circulating white blood cells and together result in IR-induced injury. To evaluate this hypothesis, we created chimeric mice by injecting wildtype bone marrow to lethally irradiated TLR2 or TLR4 deficient mice or TLR deficient bone marrow to lethally irradiated wildtype mice. The chimeric mice were subjected to intestinal IR and injury, production of complement components and TLR-mediated inflammatory products analyzed. IR-induced injury required TLR4 on the intestinal tissue whereas expression of TLR2 on either intestinal or white blood cells was sufficient for injury. In contrast, PGE2 production required TLR expression on bone marrow derived cells. TLR4 expression on non-hematopoietic tissue was sufficient for IR-induced complement C3 deposition. However, C3 was deposited on TLR2 chimeric mice if any type of wildtype cells were present, similar to intestinal injury. Together these data indicate distinct crosstalk between the specific TLRs and C3 during IR-induced injury and inflammation.
Cannabinoid receptor 1 mediates M1 type macrophage polarization by G(α)i/o/RhoA/NF-κB p65 signaling pathway in murine liver injury
Authors: Li Liying , Tian Lei , Yang Le 
Published: January 2023

Abstract
Macrophage, as an essential component of innate immunity, has emerged as a key role in liver injury. There are two main subtypes of macrophages in liver, referred to as tissue-resident Kupffer cells and bone marrow (BM)-derived monocyte/macrophages (BMMs). Macrophages are phenotypically heterogeneous and broadly characterized according to their polarization as M1/M2 types. Our previous research had demonstrated that cannabinoid receptor 1 (CB1) mediated infiltration and activation of BMMs in mouse liver injury. Here we investigated the role of CB1 in macrophage polarization. ICR mice were lethally irradiated and received BM transplants from enhanced GFP transgenic mice. Four weeks later, mice of BM reconstruction were subjected to carbon tetrachloride (CCl4)-induced liver injury. Expressions of M1 gene signatures (CD86, iNOS, IL-1b, IL-6, TNFa) in livers or cultured primary BMMs were measured by RT qPCR or Western blot. In the chimeric murine model, we found that amount of M1 type macrophages were increased from 1 to 28 days in CCl4 treatment with a maximal increase at 28 days by flow cytometry. Almost 70% of M1 type macrophages were from BMMs (CD86+EGFP+) and 30% of them were from Kupffer cells (CD86−EGFP+). Meanwhile, the dynamic changes of M1 gene signatures were consistent in injured livers by RT qPCR or Western blot. Blockage of CB1 by administration of its specific antagonist or siRNA in vivo decreased the amount of M1 type of BMMs origin, but showed little effect on that of Kupffer cells. Activation of CB1 by its agonist, ACEA, promoted M1 polarization of BMMs, depending on G(a)i/o/RhoA/NF-κB p65 signaling pathway. In conclusion, these data suggest that CB1 plays a crucial role in regulating M1 polarization of BMMs in liver injury.
Dectin-1 restores macrophage anti-Cryptococcus neoformans activity
Authors: TAVARES ALDO , BOCCA ANAMELIA 
Published: January 2023

Abstract
The interaction between macrophages and Cryptococcus neoformans (Cn) can result in fungal killing or intracellular replication. The macrophage optimal response requires the specific recognition of fungal molecular structures by a variety of pattern-recognition receptors (PRRs) receptors, mainly TLRs and CLRs.. We report that zymosan (b-glucan)-stimulated macrophages enhanced the antifungal activity against Cn. This activity depends primarily on Dectin-1 activation, with minor contribution of complement receptor 3 and/or TLR2. b-glucan-stimulation also up-regulates macrophage genes associated with an effective immune response, activation of caspase 1, enhanced IL-1b secretion and phagossome acidification. Hence, macrophage permissiveness to Cn intracellular replication is a consequence of interference by the capsule in the recognition between cell wall antigens and PPRs. Our results reveal a new role for the capsule in virulence by establishing that it prevents macrophage activation and thus prevents control of intracellular infection. Therapeutic approaches that promote macrophage activation through stimulation of Dectin-1 may be useful as adjunctive therapy for cryptococcosis.
High levels of PGE2 in bone marrow transplant mice impairs autophagy in alveolar macrophages
Authors: Martinez-Colon Giovanny Joel , Moore Bethany B 
Published: January 2023

Abstract
Bone marrow transplantation (BMT) is commonly used as a therapeutic strategy to treat different health disorders such as cancer. Although it benefits the host by restoring a damaged immune system with a healthy immune system, BMT recipients develop different complications in handling pulmonary pathogens. Previous studies have shown that immune and structural cells in the lungs of BMT recipients highly express cyclooxygenase (COX)-2, leading to overproduction of immunosuppressive prostaglandin E2 (PGE2) and may explain the susceptibility observed in BMT recipients to opportunistic pathogens such as Pseudomonas aeruginosa. Alveolar macrophages reside in the lower airways where they compose the first line of host defense against a wide array of pathogens. Previous studies have demonstrated that alveolar macrophages can target and clear pathogens such as Pseudomonas aeruginosa via autophagy, a mechanism by which pathogens are encapsulated in an autophagosome wherein the bacterial components are targeted for degradation. We have evidence that BMT recipient mouse alveolar macrophages harbor a deficiency in autophagy. To determine if PGE2 regulates autophagy in alveolar macrophages, we performed a series of in vitro and in vivo assays using a syngeneic BMT mouse model. Our results indicate impaired autophagy activity in alveolar macrophages in the presence of exogenous PGE2 as well as in the lung compartment of BMT mice. These observations highlight targeting the PGE2 signaling pathway as a method to restore immune activity in alveolar macrophages post-BMT.
Chronic HIV-1 infection induces the depletion and functional impairment of group-3 innate lymphoid cells through plasmacytoid dendritic cells and type I interferon
Authors: Zhang Zheng , Zhao Juanjuan , Cheng Liang , Wang Fu-Sheng , Su Lishan 
Published: January 2023

Abstract
Group 3 innate lymphoid cells (ILC3s) play a key role in promoting antibody production and gut inflammation and immunity; however, their characteristics and relevant regulatory mechanisms in chronic HIV-1 infection are poorly understood partially due to the lack of a robust model. We, here, reported that functional ILC3 cells are developed in all lymphoid organs in humanized mice with similar phenotypes to human counterparts. Importantly, chronic HIV-1 infection activated these tissue-resident ILC3 cells, and subsequently depleted them and preferentially impaired their IL-17a and IL-22 production in vivo of humanized mice, while anti-viral therapy efficiently reversed this alteration. HIV-1-induced depletion of ILC3s and their functional impairment could also be largely recovered by the depletion of plasmacytoid dendritic cells (pDCs) or in vivo of humanized mice and by the blockade of both interferon (IFN)-I and CD95/Fas pathway in vitro. Blockade of IFN-I also recovered IL-17a and IL-22 production in vivo of humanized mice with chronic HIV-1 infection. Additionally, we determined that HIV-1 infection induces CD95 expression on ILC3s via a pDC- and IFN-I–dependent mechanism that sensitizes ILC3s to undergo CD95/FasL-mediated apoptosis. Finally, ILC3 depletion was found to be associated with loss of gut mucosa barrier in HIV-1-infected patients. Thus, we conclude that chronic HIV-1 infection depletes ILC3s through pDC activation, induction of IFN-I, and CD95-mediated apoptosis.
The impact of lung infection on wound repair responses
Authors: Crane Meredith , Xu Yun , Henry William L. , Albina Jorge E. , Jamieson Amanda M. 
Published: January 2023

Abstract
The incidence of pulmonary infection is elevated in patients with traumatic injury, and the severity of disease, morbidity, and mortality is positively correlated with the degree of trauma. While this clinical problem is well documented, its mechanistic basis is not well understood. Current models are designed to assess the effect of trauma on the development of pneumonia, but lack the ability to measure the subsequent effect of lung infection on wound repair. We have established a model that allows for the simultaneous assessment of wound healing and lung responses in mice with surgical wounds and Influenza A virus (IAV) infection. Mice are wounded by the subcutaneous implantation of sterile polyvinyl alcohol (PVA) sponges or by excision of tail skin and infected with IAV 24 hours later. PVA sponge implantation allows for the assessment of cellular and cytokine responses to injury, while excisional tail wounding allows for the measurement of rate of repair. Our data demonstrate that IAV infection results in delayed wound repair. Furthermore, the wounds of infected mice have lower repair cytokine concentrations and decreased cellularity, mediated in part by impaired trafficking of Ly6Chi monocytes. Wounded mice with IAV infection also have elevated concentrations of proinflammatory cytokines and chemokines in the serum and bronchoalveolar lavage fluid, suggesting an inflated systemic inflammatory response. Taken together, these data indicate that the presence of viral lung infection impairs the normal progression of wound repair. Future studies will determine whether this effect is specific to viral infection, or whether other lung injuries including pulmonary bacterial infection have a similar effect on wound repair responses.
Natural killer cell dysfunction in HIV-exposed uninfected infants correlates with acquisition of lower respiratory tract infection
Authors: Smith Christiana E , Jalbert Emilie , de Almeida Volia , Mussi-Pinhata Marisa , Cohen Rachel A. , Yu Qilu , Amaral Fabiana , Pinto Jorge , Alarcon Jorge , Siberry George , Weinberg Adriana 
Published: January 2023

Abstract

Background
HIV-exposed uninfected infants (HEU) have higher rates of severe and fatal lower respiratory tract infections (LRTI) than HIV-unexposed infants (HUU), but their antibody responses to vaccines and infections do not differ. We hypothesized that natural killer cells (NK) are impaired in HEU and may predispose them to severe LRTI.

Methods
Peripheral blood mononuclear cells (PBMC) from Brazilian HEU and HUU were cryopreserved at birth and 6 months. NK phenotype and function assessed by flow cytometry after overnight incubation with and without K562 cells were compared among HEU who developed LRTI in the first 6 months of life (LRTI+), HEU who did not (LRTI−) and HUU, using Mann Whitney tests.

Results
The proportion of NK among PBMC was lower in 13 HEU vs. 22 HUU at birth (1.7% vs. 10.3%, p&lt;0.0001) and in 51 HEU vs. 72 HUU at 6 months (3.1% vs. 4.6%, p=0.0008). The proportion of stimulated NK that upregulated IFNγ (after subtraction of unstimulated controls) was lower in HEU vs. HUU at birth (0.8% vs. 2.6%, p=0.03) and at 6 months (4.1% vs. 8.5%, p=0.0008). In addition, 6 LRTI+ and 7 LRTI− HEUs differed at birth by the following: 1) K562-specific lysis was lower in LRTI+ vs. LRTI− HEU (5.6% vs. 9.9%, p=0.046); 2) The proportion of stimulated NK that upregulated IFNγ was lower in LRTI+ HEU vs. HUU (0.6% vs. 2.6%, p=0.01), but not in LRTI− HEU (2.5%); 3) Perforin upregulation of stimulated NK was absent in LRTI+ HEU (−5.9%), but present in HUU (4.6%, p=0.01 vs. LRTI+ HEU) and in LRTI− HEU (2.5%). At 6 months, there were no differences between LRTI+ and LRTI− HEU.

Conclusion
NK numbers and function are impaired in HEU. Poor NK function at birth is associated with acquisition of LRTI in the first 6 months of life and may predict infectious complications in HEU.
Novel regulation of ILC by memory CD4 T cells during protective responses against influenza A virus
Authors: Strutt Tara M , Hwang Ji Hae , Swain Susan L. 
Published: January 2023

Abstract
The primary goal of vaccination is to protect individuals from the morbidity and mortality of pathogen exposure by generating immunological memory. Our current understanding is that memory CD4 T cells, commonly regarded as the regulators of memory cytotoxic CD8 T cells and/or antibody-producing B cells, provide protection by hastening pathogen clearance through ‘faster, bigger, and better’ immune responses. It is now clear, however, that many different subsets of CD4 T cells, many with specialized functions other than providing ‘help’, are generated during immune responses against pathogens. In studies designed to ascertain the full functional potential of memory CD4 T cells responding against influenza A virus (IAV), we found that virus induced TH1-like, as well as in vitro polarized TH1 or TH17 memory CD4 T cells, enhance early innate inflammatory responses that correlate with better and earlier control of IAV in infected lungs. In further studies, we found innate lymphoid cells (ILC), which are not normally associated with anti-viral responses but rather associated with healing and wound repair, are also mobilized by memory CD4 T cells during the early stage of the response against IAV. Unexpectedly, the protection afforded by memory CD4 T cells against lethal IAV challenge is significantly compromised when ILCs are depleted. These findings reveal a previously unappreciated beneficial role of memory CD4 T cells in regulating tissue homeostasis during recall responses against pathogens through the regulation of ILC subsets.
Genomic modifiers of natural killer cells, immune responsiveness and lymphoid tissue remodeling together increase host resistance to viral infection
Authors: Teoh Jeffrey , Gillespie Alyssa L , Lee Heather , Prince Jessica , Stadnisky Michael D , Anderson Monique , Nash William T , Rival Claudia , Wei Hairong , Gamache Awndre , Farber Charles , Tung Kenneth S K , Brown Michael G 
Published: January 2023

Abstract
The MHC class I Dk molecule supplies vital host resistance during murine cytomegalovirus (MCMV) infection. Natural killer (NK) cells expressing the Ly49G2 inhibitory receptor, which specifically binds Dk, are required to control viral spread. The extent of Dk-dependent host resistance, however, differs significantly amongst related strains of mice, C57L and MA/My. As a result, we predicted that relatively small-effect modifier genetic loci might together shape immune cell features, NK cell reactivity, and the host immune response to MCMV. A robust Dk-dependent genetic effect, however, has so far hindered attempts to identify additional host resistance factors. Thus, we applied genomic mapping strategies and multicolor flow cytometric analysis of immune cells in naive and virus-infected hosts to identify genetic modifiers of the host immune response to MCMV. We discovered and validated many quantitative trait loci (QTL); these were mapped to at least 19 positions on 16 chromosomes. Intriguingly, one newly discovered non-MHC locus (Cmv5) controlled splenic NK cell accrual, secondary lymphoid organ structure, and lymphoid follicle development during MCMV infection. We infer that Cmv5 aids host resistance to MCMV infection by expanding NK cells needed to preserve and protect essential tissue structural elements, to enhance lymphoid remodeling and to increase viral clearance in spleen.