Bone marrow stromal cell antigen-1 deficiency protects from acute kidney injury.

This study aimed to investigate the role of bone marrow stromal cell antigen-1 (Bst1; also known as CD157) in acute kidney injury (AKI). Bst1 is a cell surface molecule with various enzymatic activities and downstream intracellular signaling pathways that modulate the immune response. Previous research has linked Bst1 to diseases such as ovarian cancer, Parkinson's disease, and rheumatoid arthritis. We used bilateral ischemia-reperfusion injury (IRI) as an AKI model and created bone marrow chimeric mice to evaluate the role of Bst1 in bone marrow-derived cells. We also used flow cytometry to identify Bst1/CD157 expression in hematopoietic cells and evaluate immune cell dynamics in the kidney. The findings showed that Bst1-deficient (Bst1-/-) mice were protected against renal bilateral IRI. Bone marrow chimera experiments revealed that Bst1 expression on hematopoietic cells, but not parenchymal cells, induced renal IRI. Bst1 was mainly found in B cells and neutrophils by flow cytometry of the spleen and bone marrow. In vitro, migration of neutrophils from Bst1-/- mice was suppressed, and adoptive transfer of neutrophils from wild-type Bst1+/+ mice abolished the renal protective effect in Bst1 knockout mice. In conclusion, the study demonstrated that Bst1-/- mice are protected against renal IRI and that Bst1 expression in neutrophils plays a crucial role in inducing renal IRI. These findings suggest that targeting Bst1 in neutrophils could be a potential therapeutic strategy for AKI.NEW & NOTEWORTHY Acute kidney injury (AKI), a serious disease for which there is no effective Federal Drug Administration-approved treatment, is associated with high mortality rates. Bone marrow stromal cell antigen-1 (Bst1) is a cell surface molecule that can cause kidney fibrosis, but its role in AKI is largely unknown. Our study showed that Bst1-/- mice revealed a protective effect against renal bilateral ischemia-reperfusion injury (IRI). Adoptive transfer studies confirmed that Bst1 expression in hematopoietic cells, especially neutrophils, contributed to renal bilateral IRI.

Heterogeneous macrophages contribute to the pathology of disc herniation induced radiculopathy.

BACKGROUND CONTEXT: Macrophages play important roles in the progression of intervertebral disc herniation and radiculopathy. PURPOSE: To better understand the roles of macrophages in this process, we developed a new mouse model that mimics human radiculopathy. STUDY DESIGN/SETTING: A preclinical randomized animal study. METHODS: Three types of surgeries were performed in randomly assigned Balb/c mice. These were spinal nerve exposure, traditional anterior disc puncture, and lateral disc puncture with nerve exposure (n=16/group). For the nerve exposure group, the left L5 spinal nerve was exposed without disc injury. For the traditional anterior puncture, L5/6 disc was punctured by an anterior approach as previously established. For lateral puncture with nerve exposure, the left L5 spinal nerve was exposed by removing the psoas major muscle fibers, and the L5/6 disc was punctured laterally on the left side with a 30G needle, allowing the nucleus to protrude toward the L5 spinal nerve. Mechanical hyperalgesia (pain sensitivity) of hind paws was assessed with electronic von Frey assay on alternative day for up to 2 weeks. MRI, histology, and immunostaining were performed to confirm disc herniation and inflammation. RESULTS: Ipsilateral pain in the lateral puncture with nerve exposure group was significantly greater than the other groups. Pro-inflammatory cytokines IL-1ß and IL-6 were markedly elevated at the hernia sites of both puncture groups and the spinal nerve of lateral puncture with never exposure group on postoperative day 7. Heterogeneous populations of macrophages were detected in the infiltration tissue of this mouse model and in tissue from patients undergone discectomy. CONCLUSIONS: We have established a new mouse model that mimics human radiculopathy and demonstrated that a mixed phenotype of macrophages contribute to the pathogenesis of acute discogenic radiculopathy. CLINICAL SIGNIFICANCE: This study provides a clinically relevant in vivo animal model to elucidate complex interactions of disc herniation and radicular pain, which may present opportunities for the development of macrophage-anchored therapeutics to manage radiculopathy.

Circulating fibrocytes traffic to the lung in murine acute lung injury and predict outcomes in human acute respiratory distress syndrome: a pilot study.

BACKGROUND: Fibrosis is an integral component of the pathogenesis of acute lung injury and is associated with poor outcomes in patients with acute respiratory distress syndrome (ARDS). Fibrocytes are bone marrow-derived cells that traffic to injured tissues and contribute to fibrosis; hence their concentration in the peripheral blood has the potential to serve as a biomarker of lung fibrogenesis. We therefore sought to test the hypothesis that the concentration and phenotype of circulating fibrocytes in patients with ARDS predicts clinical outcomes. METHODS: For the animal studies, C57Bl/6 mice were infected with experimental Klebsiella pneumoniae in a model of acute lung injury; one-way ANOVA was used to compare multiple groups and two-way ANOVA was used to compare two groups over time. For the human study, 42 subjects with ARDS and 12 subjects with pneumonia (without ARDS) were compared to healthy controls. Chi-squared or Fisher's exact test were used to compare binary outcomes. Survival data was expressed using a Kaplan-Meier curve and compared by log-rank test. Univariable and multivariable logistic regression were used to predict death. RESULTS: In mice with acute lung injury caused by Klebsiella pneumonia, there was a time-dependent increase in lung soluble collagen that correlated with sequential expansion of fibrocytes in the bone marrow, blood, and then lung compartments. Correspondingly, when compared via cross-sectional analysis, the initial concentration of blood fibrocytes was elevated in human subjects with ARDS or pneumonia as compared to healthy controls. In addition, fibrocytes from subjects with ARDS displayed an activated phenotype and on serial measurements, exhibited intermittent episodes of markedly elevated concentration over a median of 1 week. A peak concentration of circulating fibrocytes above a threshold of > 4.8 × 106 cells/mL cells correlated with mortality that was independent of age, ratio of arterial oxygen concentration to the fraction of inspired oxygen, and vasopressor requirement. CONCLUSIONS: Circulating fibrocytes increase in a murine model of acute lung injury and elevation in the number of these cells above a certain threshold is correlated with mortality in human ARDS. Therefore, these cells may provide a useful and easily measured biomarker to predict outcomes in these patients.

Interactions among glomerulus infiltrating macrophages and intrinsic cells via cytokines in chronic lupus glomerulonephritis.

Inflammation plays a key role in the pathogenesis of lupus nephritis (LN) and inflammatory cytokines within the glomeruli are critical in this process. However, little information is available for the identities of the cell types that are primarily responsible for the production and function of the various cytokines. We have devised a novel method to visualize cytokine signals in the kidney by confocal microscopy and found that cytokine production within the glomerulus is cell type-specific and under translational control. In the lupus-prone NZM2328 mice with chronic glomerulonephritis, IL-6, IL-1ß, and TNF-α in the glomerulus were produced predominantly by mesangial cells, podocytes, and glomerulus-infiltrating blood-derived macrophages, respectively. Microarray and RNASeq analyses showed that these cells expressed the receptors for these cytokines. Together the 3 cell types form a cytokine circuit in amplifying cytokine responses in LN. The intrinsic cells and infiltrating macrophages also produced other cytokines including M-CSF, SCF, and IL-34 that constituted within the enclosed glomerular space the soluble effector milieu which may mediate cellular damage and proliferation, and cytokine transcriptional and translation regulation. IL-10 and IL-1ß were translationally regulated in the glomeruli in the intact kidney in a cell type-specific manner. The production of these 2 cytokines by infiltrating macrophages was undetectable in a visualization system for in situ protein accumulation despite high mRNA expression levels. However, these macrophages in isolated glomeruli which are released from Bowman's capsules produced large amounts of IL-10 and IL-1ß. These data reveal the complexity of cytokine regulation, production, and function in the glomerulus and provide a model in which cytokine blocking may be beneficial in LN treatment.

GSTM1 Deletion Exaggerates Kidney Injury in Experimental Mouse Models and Confers the Protective Effect of Cruciferous Vegetables in Mice and Humans.

BACKGROUND: GSTM1 encodes glutathione S-transferase µ-1 (GSTM1), which belongs to a superfamily of phase 2 antioxidant enzymes. The highly prevalent GSTM1 deletion variant is associated with kidney disease progression in human cohorts: the African American Study of Kidney Disease and Hypertension and the Atherosclerosis Risk in Communities (ARIC) Study. METHODS: We generated a Gstm1 knockout mouse line to study its role in a CKD model (involving subtotal nephrectomy) and a hypertension model (induced by angiotensin II). We examined the effect of intake of cruciferous vegetables and GSTM1 genotypes on kidney disease in mice as well as in human ARIC study participants. We also examined the importance of superoxide in the mediating pathways and of hematopoietic GSTM1 on renal inflammation. RESULTS: Gstm1 knockout mice displayed increased oxidative stress, kidney injury, and inflammation in both models. The central mechanism for kidney injury is likely mediated by oxidative stress, because treatment with Tempol, an superoxide dismutase mimetic, rescued kidney injury in knockout mice without lowering BP. Bone marrow crosstransplantation revealed that Gstm1 deletion in the parenchyma, and not in bone marrow-derived cells, drives renal inflammation. Furthermore, supplementation with cruciferous broccoli powder rich in the precursor to antioxidant-activating sulforaphane significantly ameliorated kidney injury in Gstm1 knockout, but not wild-type mice. Similarly, among humans (ARIC study participants), high consumption of cruciferous vegetables was associated with fewer kidney failure events compared with low consumption, but this association was observed primarily in participants homozygous for the GSTM1 deletion variant. CONCLUSIONS: Our data support a role for the GSTM1 enzyme in the modulation of oxidative stress, inflammation, and protective metabolites in CKD.

Perivascular CD73+ cells attenuate inflammation and interstitial fibrosis in the kidney microenvironment.

Progressive tubulointerstitial fibrosis may occur after acute kidney injury due to persistent inflammation. Purinergic signaling by 5'-ectonucleotidase, CD73, an enzyme that converts AMP to adenosine on the extracellular surface, can suppress inflammation. The role of CD73 in progressive kidney fibrosis has not been elucidated. We evaluated the effect of deletion of CD73 from kidney perivascular cells (including pericytes and/or fibroblasts of the Foxd1+ lineage) on fibrosis. Perivascular cell expression of CD73 was necessary to suppress inflammation and prevent kidney fibrosis in Foxd1CreCD73fl/fl mice evaluated 14 days after unilateral ischemia-reperfusion injury or folic acid treatment (250 mg/kg). Kidneys of Foxd1CreCD73fl/fl mice had greater collagen deposition, expression of proinflammatory markers (including various macrophage markers), and platelet-derived growth factor recepetor-ß immunoreactivity than CD73fl/fl mice. Kidney dysfunction and fibrosis were rescued by administration of soluble CD73 or by macrophage deletion. Isolated CD73-/- kidney pericytes displayed an activated phenotype (increased proliferation and α-smooth muscle actin mRNA expression) compared with wild-type controls. In conclusion, CD73 in perivascular cells may act to suppress myofibroblast transformation and influence macrophages to promote a wound healing response. These results suggest that the purinergic signaling pathway in the kidney interstitial microenvironment orchestrates perivascular cells and macrophages to suppress inflammation and prevent progressive fibrosis.

Monocyte-Derived Dendritic Cells as Antigen-Presenting Cells in T-Cell Proliferation and Cytokine Production.

Dendritic cells (DC) are the most potent antigen-presenting cells that link innate with adaptive immunity. They circulate the body and sample the microenvironments for maintaining homeostasis and for mounting T-cell responses against invading pathogens, foreign antigens, and aberrant self-proteins. In humans, DC derived from blood monocytes (MDC) by cytokine treatment provide the most abundant and versatile source for studying DC and T-cell biology, and for use as adjuvants in cancer therapy. In asthma patients, T-cell functions are studied by using autologous MDC as accessory cells for allergen presentation. The method for isolating T cells and monocytes from peripheral blood mononuclear cells (PBMC) and the stimulation of T cells to proliferate and produce cytokines by MDC are outlined in this chapter. The method can be applied to the functional studies of T cells and DC in other diseases.

IL233, an IL-2-IL-33 hybrid cytokine induces prolonged remission of mouse lupus nephritis by targeting Treg cells as a single therapeutic agent.

Lupus glomerulonephritis (GN) is an autoimmune disease characterized by immune complex-deposition, complement activation and glomerular inflammation. In lupus-prone NZM2328 mice, the occurrence of lupus GN was accompanied by a decrease in Treg cells and an increase in proinflammatory cytokine-producing T cells. Because IL-33 in addition to IL-2 has been shown to be important for Treg cell proliferation and ST2 (IL-33 receptor) positive Treg cells are more potent in suppressor activity, a hybrid cytokine with active domains of IL-2 and IL-33 was generated to target the ST2+ Treg cells as a therapeutic agent to treat lupus GN. Three mouse models were used: spontaneous and Ad-IFNα- accelerated lupus GN in NZM2328 and the lymphoproliferative autoimmune GN in MRL/lpr mice. Daily injections of IL233 for 5 days prevented Ad-IFNα-induced lupus GN and induced remission of spontaneous lupus GN. The remission was permanent in that no relapses were detected. The remission was accompanied by persistent elevation of Treg cells in the renal lymph nodes. IL233 is more potent than IL-2 and IL-33 either singly or in combination in the treatment of lupus GN. The results of this study support the thesis that IL233 should be considered as a novel agent for treating lupus GN.

Podocyte Activation of NLRP3 Inflammasomes Contributes to the Development of Proteinuria in Lupus Nephritis.

OBJECTIVE: Development of proteinuria in lupus nephritis (LN) is associated with podocyte dysfunction. The NLRP3 inflammasome has been implicated in the pathogenesis of LN. The purpose of this study was to investigate whether NLRP3 inflammasome activation is involved in the development of podocyte injury in LN. METHODS: A fluorescence-labeled caspase 1 inhibitor probe was used to detect the activation of NLRP3 inflammasomes in podocytes derived from lupus-prone NZM2328 mice and from renal biopsy tissues obtained from patients with LN. MCC950, a selective inhibitor of NLRP3, was used to treat NZM2328 mice. Proteinuria, podocyte ultrastructure, and renal pathology were evaluated. In vitro, sera from diseased NZM2328 mice were used to stimulate a podocyte cell line, and the cells were analyzed by flow cytometry. RESULTS: NLRP3 inflammasomes were activated in podocytes from lupus-prone mice and from patients with LN. Inhibition of NLRP3 with MCC950 ameliorated proteinuria, renal histologic lesions, and podocyte foot process effacement in lupus-prone mice. In vitro, sera from diseased NZM2328 mice activated NLRP3 inflammasomes in the podocyte cell line through the production of reactive oxygen species. CONCLUSION: NLRP3 inflammasomes were activated in podocytes from lupus-prone mice and from LN patients. Activation of NLRP3 is involved in the pathogenesis of podocyte injuries and the development of proteinuria in LN.

Dependence of Glomerulonephritis Induction on Novel Intraglomerular Alternatively Activated Bone Marrow-Derived Macrophages and Mac-1 and PD-L1 in Lupus-Prone NZM2328 Mice.

Glomerular damage mediated by glomerulus-infiltrating myeloid-derived cells is a key pathogenic event in lupus nephritis (LN), but the process is poorly understood. Confocal microscopy of kidney sections and flow cytometry analysis of glomerular cells from magnetic bead-purified glomeruli have identified glomerulus-infiltrating leukocyte populations in NZM2328 (NZM) lupus-prone mice with spontaneous chronic glomerulonephritis (GN) and anti-glomerular basement membrane-induced nephritis. The occurrence of a major glomerulus-infiltrating CD11b+F4/80-I-A- macrophage population exhibiting the markers programmed death ligand-1 (PD-L1), Mac-2, and macrophage mannose receptor (CD206) and producing Klf4, Il10, Retnla, Tnf, and Il6 mRNA, which are known to be expressed by alternatively activated (M2b) macrophages, correlated with proteinuria status. In NZM mice with spontaneous LN, glomerular macrophage infiltration is predominant. CD11b+F4/80-I-A- intraglomerular macrophages and polymorphonuclear neutrophils (PMN) are important in inducing GN, as anti-CD11b and -ICAM-1 mAb inhibited both proteinuria and macrophage and PMN infiltration. The predominant and high expression of PD-L1 by CD11b+F4/80-I-A- glomerular macrophages in kidneys of mice with GN and the inhibition of proteinuria by anti-PD-L1 mAb supported the pathogenic role of these macrophages but not the PD-L1- PMN in GN development and in inducing podocyte damage. In NZM mice with spontaneous chronic GN and severe proteinuria, few glomerulus-infiltrating PMN were found, leaving macrophages and, to a less extent, dendritic cells as the major infiltrating leukocytes. Taken together, these data support the important pathogenic effect of CD11b+F4/80-I-A- M2b-like glomerulus-infiltrating macrophages in LN and reinforce macrophages as a promising target for GN treatment.

Cross-Presentation of Soluble and Cell-Associated Antigen by Murine Hepatocytes Is Enhanced by Collectrin Expression.

Cross-presentation is a modular series of intracellular events dictating the internalization and subsequent MHC class I (MHC I) display of extracellular Ags. This process has been defined in dendritic cells and plays a fundamental role in the induction of CD8+ T cell immunity during viral, intracellular bacterial, and antitumor responses. Herein, acute viral infection of murine liver with adenovirus, a model for intrahepatic cross-presentation, confirms hepatocytes directly contribute to cross-presentation of Ags and priming the pool of naive CD8+ T cells within the liver microenvironment. Processing of soluble and cell-associated Ags into peptide displayed by MHC I is however defective in hepatocytes lacking collectrin, an intracellular chaperone protein that localizes within the endoplasmic reticulum-Golgi intermediate compartment. Loss of hepatic collectrin expression leads to the diminished cross-priming and expansion of cytolytic antiviral CD8+ T cells. This study demonstrates that collectrin positively regulates processing of engulfed Ags into MHC I:peptide complexes within hepatocytes. Collectrin-mediated cross-presentation supports intrahepatic adaptive antiviral immune responses and may lead to insights into the nature of how the liver acts as a primary site of CD8+ T cell activation.

Murine liver-resident group 1 innate lymphoid cells regulate optimal priming of anti-viral CD8+ T cells.

The liver contains 2 transcriptionally distinct group 1 ILC subsets: CD49a+ ILC1s and CD49b+ NK cells. However, little is known about how group 1 ILCs contribute to hepatic immune responses. Therefore, we characterized murine liver-resident group 1 ILCs and found that CD49a+ ILC1s express high levels of the inhibitory receptor NKG2A and localize near DCs in perivascular spaces surrounding the portal triads. Upon hepatic viral infection, NKG2A signaling in group 1 ILCs, especially in CD49a+ ILC1s, inhibits CXCL9 expression required for robust accumulation of IFN-γ+CD49b+ NK cells. As a consequence, NKG2A-/- mice showed increased numbers of IFN-γ-producing NK cells that preferentially activate liver CD103+ DCs, leading to the sustained proliferation of adoptively transferred, virus-specific CD8+ T cells. Collectively, these data suggest that group 1 ILCs play a role in maintaining the liver as a tolerogenic site by limiting the recruitment of peripheral NK cells during the early phase of viral infection. Furthermore, our findings implicate that the inhibition of NKG2A signaling on group 1 ILCs may be a novel vaccine strategy to induce robust CD8+ T cell responses against persistent liver pathogens.

Expression of scavenger receptor-AI promotes alternative activation of murine macrophages to limit hepatic inflammation and fibrosis.

The liver maintains an immunologically tolerant environment as a result of continuous exposure to food and bacterial constituents from the digestive tract. Hepatotropic pathogens can take advantage of this niche and establish lifelong chronic infections causing hepatic fibrosis and hepatocellular carcinoma. Macrophages (Mϕ) play a critical role in regulation of immune responses to hepatic infection and regeneration of tissue. However, the factors crucial for Mϕ in limiting hepatic inflammation or resolving liver damage have not been fully understood. In this report, we demonstrate that expression of C-type lectin receptor scavenger receptor-AI (SR-AI) is crucial for promoting M2-like Mϕ activation and polarization during hepatic inflammation. Liver Mϕ uniquely up-regulated SR-AI during hepatotropic viral infection and displayed increased expression of alternative Mϕ activation markers, such as YM-1, arginase-1, and interleukin-10 by activation of mer receptor tyrosine kinase associated with inhibition of mammalian target of rapamycin. Expression of these molecules was reduced on Mϕ obtained from livers of infected mice deficient for the gene encoding SR-AI (msr1). Furthermore, in vitro studies using an SR-AI-deficient Mϕ cell line revealed impeded M2 polarization and decreased phagocytic capacity. Direct stimulation with virus was sufficient to activate M2 gene expression in the wild-type (WT) cell line, but not in the knockdown cell line. Importantly, tissue damage and fibrosis were exacerbated in SR-AI-/- mice following hepatic infection and adoptive transfer of WT bone-marrow-derived Mϕ conferred protection against fibrosis in these mice. CONCLUSION: SR-AI expression on liver Mϕ promotes recovery from infection-induced tissue damage by mediating a switch to a proresolving Mϕ polarization state. (Hepatology 2017;65:32-43).

Proximal Tubule CD73 Is Critical in Renal Ischemia-Reperfusion Injury Protection.

CD73-derived adenosine plays an anti-inflammatory role in various organs. However, its role in renal ischemia-reperfusion injury (IRI) is controversial. We targeted CD73 mutant mice to determine the function of CD73 expressed by various renal cell types under mild IRI conditions. Mice with CD73 deletion in proximal tubules exhibited exacerbated IRI, comparable with that of CD73-/- mice compared with WT mice. Mice with CD73 deletions in other cell types, including cortical type 1 fibroblast-like cells, mesangial cells, macrophages, and dendritic cells, showed small or no increases in injury above control mice when subjected to threshold levels of ischemia. Results from adoptive transfer experiments between WT and CD73-/- mice and pharmacologic studies modulating enzymatic activity of CD73 and extracellular adenosine levels supported a critical role of adenosine generated by proximal tubule CD73 expression in abrogating IRI. Renal adenosine levels were lower before and after ischemia in CD73-deficient mice. However, reduction in total acid-extractable renal adenosine levels was inadequate to explain the marked difference in kidney injury in these CD73-deficient mice. Furthermore, CD73 inhibition and enzyme replacement studies showed no change in total kidney adenosine levels in treated mice compared with vehicle-treated controls. Protection from IRI in neutrophil-depleted WT recipients was sustained by repopulation with bone marrow neutrophils from WT mice but not by those lacking adenosine 2a receptors (from Adora2a-/- mice). These data support the thesis that local adenosine generated by cells at the injury site is critical for protection from IRI through bone marrow-derived adenosine 2a receptors.

Vagus nerve stimulation mediates protection from kidney ischemia-reperfusion injury through α7nAChR+ splenocytes.

The nervous and immune systems interact in complex ways to maintain homeostasis and respond to stress or injury, and rapid nerve conduction can provide instantaneous input for modulating inflammation. The inflammatory reflex referred to as the cholinergic antiinflammatory pathway regulates innate and adaptive immunity, and modulation of this reflex by vagus nerve stimulation (VNS) is effective in various inflammatory disease models, such as rheumatoid arthritis and inflammatory bowel disease. Effectiveness of VNS in these models necessitates the integration of neural signals and α7 nicotinic acetylcholine receptors (α7nAChRs) on splenic macrophages. Here, we sought to determine whether electrical stimulation of the vagus nerve attenuates kidney ischemia-reperfusion injury (IRI), which promotes the release of proinflammatory molecules. Stimulation of vagal afferents or efferents in mice 24 hours before IRI markedly attenuated acute kidney injury (AKI) and decreased plasma TNF. Furthermore, this protection was abolished in animals in which splenectomy was performed 7 days before VNS and IRI. In mice lacking α7nAChR, prior VNS did not prevent IRI. Conversely, adoptive transfer of VNS-conditioned α7nAChR splenocytes conferred protection to recipient mice subjected to IRI. Together, these results demonstrate that VNS-mediated attenuation of AKI and systemic inflammation depends on α7nAChR-positive splenocytes.

Liver-resident CD103+ dendritic cells prime antiviral CD8+ T cells in situ.

The liver maintains a tolerogenic environment to avoid unwarranted activation of its resident immune cells upon continuous exposure to food and bacterially derived Ags. However, in response to hepatotropic viral infection, the liver's ability to switch from a hyporesponsive to a proinflammatory environment is mediated by select sentinels within the parenchyma. To determine the contribution of hepatic dendritic cells (DCs) in the activation of naive CD8(+) T cells, we first characterized resident DC subsets in the murine liver. Liver DCs exhibit unique properties, including the expression of CD8α (traditionally lymphoid tissue specific), CD11b, and CD103 markers. In both the steady-state and following viral infection, liver CD103(+) DCs express high levels of MHC class II, CD80, and CD86 and contribute to the high number of activated CD8(+) T cells. Importantly, viral infection in the Batf3(-/-) mouse, which lacks CD8α(+) and CD103(+) DCs in the liver, results in a 3-fold reduction in the proliferative response of Ag-specific CD8(+) T cells. Limiting DC migration out of the liver does not significantly alter CD8(+) T cell responsiveness, indicating that CD103(+) DCs initiate the induction of CD8(+) T cell responses in situ. Collectively, these data suggest that liver-resident CD103(+) DCs are highly immunogenic in response to hepatotropic viral infection and serve as a major APC to support the local CD8(+) T cell response. It also implies that CD103(+) DCs present a promising cellular target for vaccination strategies to resolve chronic liver infections.

Interferon alpha on NZM2328.Lc1R27: enhancing autoimmunity and immune complex-mediated glomerulonephritis without end stage renal failure.

Interferon alpha (IFNα) may play a significant role in systemic lupus erythematosus (SLE) pathogenesis. Recent literature suggests that IFNα does not correlate with disease activities and blockade of IFNα is not effective in treating SLE. This study aims to delineate further the role of IFNα in SLE. 12-week old NZM2328 and its congenic NZM2328.Lc1R27 (R27) female mice were challenged with adenovirus-IFNα (adeno-IFNα) or adenovirus-LacZ (adeno-LacZ). Only adeno-IFNα treated NZM2328 developed severe proteinuria and died of chronic glomerulonephritis (GN) and end stage renal disease. Adeno-IFNα treated R27 did develop immune complex-mediated GN but had normal renal function. Adeno-LacZ treated NZM2328 showed enlarged glomeruli and increased cellularity without immune complex deposition. Adeno-LacZ treated R27 did not show serological and histological abnormalities. Adeno-IFNα induced anti-dsDNA and anti-kidney autoantibodies in NZM2328 and R27. These results suggest that end organ damage is host-dependent and less related to autoimmunity and may have significant implications in SLE pathogenesis.

Cgnz1 allele confers kidney resistance to damage preventing progression of immune complex-mediated acute lupus glomerulonephritis.

Cgnz1 and Agnz1 on the distal region of mouse chromosome 1 are associated with chronic glomerulonephritis (cGN) and acute GN (aGN). NZM2328.Lc1R27 (R27) was generated by introgressing a C57L/J region where Cgnz1 is located to NZM2328. R27 female mice developed aGN mediated by immune complex (IC) deposition and complement activation without progression to cGN with severe proteinuria. End stage renal disease (ESRD) was not seen in R27 mice as old as 15 mo. Thus, aGN and cGN are under separate genetic control, and IC-mediated proliferative GN need not progress to cGN and ESRD. NZM2328 and R27 female mice have comparable immune and inflammatory parameters. In contrast to NZM2328, R27 mice were resistant to sheep anti-mouse GBM serum-induced nephritis, supporting the hypothesis that aGN is mediated by autoimmunity and resistance to the development of cGN is mediated by end organ resistance to damage. Thus, autoimmunity should be considered distinct from end organ damage. The Cgnz1 region has been mapped to a 1.34 MB region with 45 genes. Nine candidate genes were identified. Clinical relevance of these observations is supported by case studies. Clinical implications and the significance to human lupus and other diseases are presented.

Lipidoid Nanoparticles Containing PD-L1 siRNA Delivered In Vivo Enter Kupffer Cells and Enhance NK and CD8(+) T Cell-mediated Hepatic Antiviral Immunity.

Effective clinical application of antiviral immunotherapies necessitates enhancing the functional state of natural killer (NK) and CD8(+) T cells. An important mechanism for the establishment of viral persistence in the liver is the activation of the PD-1/PD-L1 inhibitory pathway. To examine the role of hepatic myeloid PD-L1 expression during viral infection, we determined the magnitude and quality of antiviral immune responses by administering PD-L1 short-interfering RNA (siRNA) encapsulated in lipidoid nanoparticles (LNP) in mice. Our studies indicate that Kupffer cells (KC) preferentially engulfed PD-L1 LNP within a short period of time and silenced Pdl1 during adenovirus and MCMV infection leading to enhanced NK and CD8(+) T cell intrahepatic accumulation, effector function (interferon (IFN)-γ and granzyme B (GrB) production), CD8(+) T cell-mediated viral clearance, and memory. Our results demonstrate that PD-L1 knockdown on KCs is central in determining the outcome of liver viral infections, and they represent a new class of gene therapy.Molecular Therapy - Nucleic Acids (2013) 2, e72; doi:10.1038/mtna.2012.63; published online 19 February 2013.

Serum and salivary IgE, IgA, and IgG4 antibodies to Dermatophagoides pteronyssinus and its major allergens, Der p1 and Der p2, in allergic and nonallergic children.

Allergic rhinitis (AR) is a public health problem with high prevalence worldwide. We evaluated levels of specific IgE, IgA, and IgG4 antibodies to the Dermatophagoides pteronyssinus (Dpt) house dust mite and to its major allergens (Der p1 and Der p2) in serum and saliva samples from allergic and nonallergic children. A total of 86 children were analyzed, from which 72 had AR and 14 were nonallergic healthy children. Serum IgE and serum/salivary IgG4 levels to Dpt, Der p1, and Der p2 were higher in allergic children whereas serum/salivary IgA levels to all allergens were higher in nonallergic children. IgE levels positively correlated with IgG4 and IgA to all allergens in allergic children, while IgA levels negatively correlated with IgG4 to Dpt and Der p1 in nonallergic children. In conclusion, mite-specific IgA antibodies predominate in the serum and saliva of nonallergic children whereas mite-specific IgE and IgG4 are prevalent in allergic children. The presence of specific IgA appears to have a key role for the healthy immune response to mucosal allergens. Also, specific IgA measurements in serum and/or saliva may be useful for monitoring activation of tolerance-inducing mechanisms during allergen specific immunotherapeutic procedures, especially sublingual immunotherapy.