Vagus nerve stimulation modulates distinct acetylcholine receptors on B cells and limits the germinal center response

Acetylcholine is produced in the spleen in response to vagus nerve activation; however, the effects on antibody production have been largely unexplored. Here, we use a chronic vagus nerve stimulation (VNS) mouse model to study the effect of VNS on T-dependent B cell responses. We observed lower titers of high-affinity IgG and fewer antigen-specific germinal center (GC) B cells. GC B cells from chronic VNS mice exhibited altered mRNA and protein expression suggesting increased apoptosis and impaired plasma cell differentiation. Follicular dendritic cell (FDC) cluster dispersal and altered gene expression suggested poor function. The absence of acetylcholine-producing CD4+ T cells diminished these alterations. In vitro studies revealed that α7 and α9 nicotinic acetylcholine receptors (nAChRs) directly regulated B cell production of TNF, a cytokine crucial to FDC clustering. α4 nAChR inhibited coligation of CD19 to the B cell receptor, presumably decreasing B cell survival. Thus, VNS-induced GC impairment can be attributed to distinct effects of nAChRs on B cells.

Host factor TIMP1 sustains long-lasting myeloid-biased hematopoiesis after severe infection

Infection is able to promote innate immunity by enhancing a long-term myeloid output even after the inciting infectious agent has been cleared. However, the mechanisms underlying such a regulation are not fully understood. Using a mouse polymicrobial peritonitis (sepsis) model, we show that severe infection leads to increased, sustained myelopoiesis after the infection is resolved. In post-infection mice, the tissue inhibitor of metalloproteinases 1 (TIMP1) is constitutively upregulated. TIMP1 antagonizes the function of ADAM10, an essential cleavage enzyme for the activation of the Notch signaling pathway, which suppresses myelopoiesis. While TIMP1 is dispensable for myelopoiesis under the steady state, increased TIMP1 enhances myelopoiesis after infection. Thus, our data establish TIMP1 as a molecular reporter of past infection in the host, sustaining hyper myelopoiesis and serving as a potential therapeutic target for modulating HSPC cell fate.

Efficacy of an isoxazole-3-carboxamide analog of pleconaril in mouse models of Enterovirus-D68 and Coxsackie B5

Enteroviruses (EV) cause a number of life-threatening infectious diseases. EV-D68 is known to cause respiratory illness in children that can lead to acute flaccid myelitis. Coxsackievirus B5 (CVB5) is commonly associated with hand-foot-mouth disease. There is no antiviral treatment available for either. We have developed an isoxazole-3-carboxamide analog of pleconaril (11526092) which displayed potent inhibition of EV-D68 (IC50 58 nM) as well as other enteroviruses including the pleconaril-resistant Coxsackievirus B3-Woodruff (IC50 6-20 nM) and CVB5 (EC50 1 nM). Cryo-electron microscopy structures of EV-D68 in complex with 11526092 and pleconaril demonstrate destabilization of the EV-D68 MO strain VP1 loop, and a strain-dependent effect. A mouse respiratory model of EV-D68 infection, showed 3-log decreased viremia, favorable cytokine response, as well as statistically significant 1-log reduction in lung titer reduction at day 5 after treatment with 11526092. An acute flaccid myelitis neurological infection model did not show efficacy. 11526092 was tested in a mouse model of CVB5 infection and showed a 4-log TCID50 reduction in the pancreas. In summary, 11526092 represents a potent in vitro inhibitor of EV with in vivo efficacy in EV-D68 and CVB5 animal models suggesting it is worthy of further evaluation as a potential broad-spectrum antiviral therapeutic against EV.

Circulating Th17 T cells at treatment onset predict autoimmune toxicity of PI3Kδ inhibitors

PI3Kδ inhibitors are approved for the therapy of B cell malignancies, but their clinical use has been limited by unpredictable autoimmune toxicity, despite promising efficacy and evidence that toxicity is associated with improved clinical outcomes. Prior phenotypic evaluation by CyTOF has identified increases in activated CD8 T cells with activation of Th17 T cells, as well as decreases in Tregs, particularly in patients with toxicity. Here we sought to further understand the effects of idelalisib and duvelisib in vitro, and demonstrate that both idelalisib and duvelisib can inhibit T cell proliferation as well as Th1 and Treg differentiation in vitro, while promoting Th2 and Th17 differentiation. We further demonstrate directly using intracellular flow cytometry that autoimmune toxicity in patients is associated with higher absolute numbers of CD4 and CD8 T cells with Th17 differentiation in peripheral blood prior to therapy, and that gastrointestinal tissues from patients with active autoimmune complications of PI3Kδ inhibitors show infiltration with Th17+ T cells. These same tissues show depletion of Tregs as compared to CLL patients without toxicity, suggesting that loss of Tregs may be permissive for Th17 activation to lead to autoimmune toxicity. Clinical trials to restore this balance are warranted.

Galantamine attenuates autoinflammation in a mouse model of familial mediterranean fever

BACKGROUND

Autoinflammatory diseases, a diverse group of inherited conditions characterized by excessive innate immune activation, have limited therapeutic options. Neuroimmune circuits of the inflammatory reflex control innate immune overactivation and can be stimulated to treat disease using the acetylcholinesterase inhibitor galantamine.

METHODS

We tested the efficacy of galantamine in a rodent model of the prototypical autoinflammatory disease familial Mediterranean fever (FMF). Multiple chronic disease markers were evaluated in animals that received long-term galantamine treatment compared to vehicle.

RESULTS

Long-term treatment with galantamine attenuated the associated splenomegaly and anemia which are characteristic features of this disease. Further, treatment reduced inflammatory cell infiltration into affected organs and a subcutaneous air pouch.

CONCLUSIONS

These findings suggest that galantamine attenuates chronic inflammation in this mouse model of FMF. Further research is warranted to explore the therapeutic potential of galantamine in FMF and other autoinflammatory diseases.

Thiocarbazate building blocks enable the construction of azapeptides for rapid development of therapeutic candidates

Peptides, polymers of amino acids, comprise a vital and expanding therapeutic approach. Their rapid degradation by proteases, however, represents a major limitation to their therapeutic utility and chemical modifications to native peptides have been employed to mitigate this weakness. Herein, we describe functionalized thiocarbazate scaffolds as precursors of aza-amino acids, that, upon activation, can be integrated in a peptide sequence to generate azapeptides using conventional peptide synthetic methods. This methodology facilitates peptide editing-replacing targeted amino acid(s) with aza-amino acid(s) within a peptide-to form azapeptides with preferred therapeutic characteristics (extending half-life/bioavailability, while at the same time typically preserving structural features and biological activities). We demonstrate the convenience of this azapeptide synthesis platform in two well-studied peptides with short half-lives: FSSE/P5779, a tetrapeptide inhibitor of HMGB1/MD-2/TLR4 complex formation, and bradykinin, a nine-residue vasoactive peptide. This bench-stable thiocarbazate platform offers a robust and universal approach to optimize peptide-based therapeutics.

Activated CLL cells regulate IL17F producing Th17 cells in miR155 dependent and outcome specific manners

Chronic lymphocytic leukemia (CLL) results from expansion of a CD5+ B-cell clone that requires interactions with other cell types, including T cells. Moreover, CLL patients have elevated circulating IL17A+ and IL17F+ CD4+ T cells (Th17s), with higher IL17A+Th17s correlating with better outcomes. We report that CLL Th17s express more miR155, a Th17 differentiation regulator, than control Th17s, despite naïve CD4+ T cell (TN) basal miR155 levels being similar in both. We also found that CLL cells directly regulate miR155 levels in TN, thereby affecting Th17 differentiation by documenting that: co-culturing TN with resting (Brest) or activated (Bact) CLL cells alters the magnitude and direction of T-cell miR155 levels; CLL Bact promote IL17A+ and IL17F+ T cell generation by a miR155-dependent mechanism, confirmed by miR155 inhibition; co-cultures of TN with CLL Bact lead to a linear correlation between the degree and direction of T-cell miR155 expression changes and IL17F production, but not IL17A; Bact-mediated changes in TN miR155 expression correlate with outcome, irrespective of IGHV mutation status, a strong prognostic indicator. Together, the results identify a previously unrecognized CLL Bact-dependent mechanism, upregulation of TN miR155 expression and subsequent enhancement of IL17F+ Th17 generation, that favors better clinical courses.

Follicular dendritic cell dysfunction contributes to impaired antigen-specific humoral responses in sepsis-surviving mice

Sepsis survivors exhibit impaired responsiveness to antigen (Ag) challenge associated with increased mortality from infection. The contribution of follicular dendritic cells (FDCs) in the impaired humoral response in sepsis-surviving mice is investigated in this study. We demonstrated that mice subjected to sepsis from cecal ligation and puncture (CLP mice) have reduced NP-specific high-affinity class-switched Ig antibodies (Abs) compared with sham-operated control mice following immunization with the T cell-dependent Ag, NP-CGG. NP-specific germinal center (GC) B cells in CLP mice exhibited reduced TNF-α and AID mRNA expression compared with sham-operated mice. CLP mice showed a reduction in FDC clusters, a reduced binding of immune complexes on FDCs, and reduced mRNA expression of CR2, ICAM-1, VCAM-1, FcγRIIB, TNFR1, IKK2, and LTβR compared with sham-operated mice. Adoptive transfer studies showed that there was no B cell-intrinsic defect. In summary, our data suggest that the reduced Ag-specific Ab response in CLP mice is secondary to a disruption in FDC and GC B cell function.

Autocrine and paracrine interferon signalling as 'ring vaccination' and 'contact tracing' strategies to suppress virus infection in a host

The innate immune response, particularly the interferon response, represents a first line of defence against viral infections. The interferon molecules produced from infected cells act through autocrine and paracrine signalling to turn host cells into an antiviral state. Although the molecular mechanisms of IFN signalling have been well characterized, how the interferon response collectively contribute to the regulation of host cells to stop or suppress viral infection during early infection remain unclear. Here, we use mathematical models to delineate the roles of the autocrine and the paracrine signalling, and show that their impacts on viral spread are dependent on how infection proceeds. In particular, we found that when infection is well-mixed, the paracrine signalling is not as effective; by contrast, when infection spreads in a spatial manner, a likely scenario during initial infection in tissue, the paracrine signalling can impede the spread of infection by decreasing the number of susceptible cells close to the site of infection. Furthermore, we argue that the interferon response can be seen as a parallel to population-level epidemic prevention strategies such as ‘contact tracing’ or ‘ring vaccination’. Thus, our results here may have implications for the outbreak control at the population scale more broadly.

Chronic lymphocytic leukemia-like monoclonal B-cell lymphocytosis exhibits an increased inflammatory signature that is reduced in early-stage chronic lymphocytic leukemia

Several studies in chronic lymphocytic leukemia (CLL) patients have reported impaired immune cell functions, which contribute to tumor evasion and disease progression. However, studies on CLL-like monoclonal B-cell lymphocytosis (MBL) are scarce. In the study described here, we characterized the immune environment in 62 individuals with clinical MBL, 56 patients with early-stage CLL, and 31 healthy controls. Gene expression arrays and quantitative reverse transcription polymerase chain reaction were performed on RNA from CD4⁺ peripheral blood cells; serum cytokines were measured with immunoassays; and HLA-DR expression on circulating monocytes, as well as the percentages of Th1, cytotoxic, exhausted, and effector CD4⁺ T cells, were evaluated by flow cytometry. In addition, cell cultures of clonal B cells and CD14-enriched or -depleted cell fractions were performed. Strikingly, MBL and early-stage CLL differed in pro-inflammatory signatures. An increased inflammatory drive orchestrated mainly by monocytes was identified in MBL, which exhibited enhanced phagocytosis, pattern recognition receptors, interleukin-8 (IL8), HMGB1, and acute response signaling pathways and increased pro-inflammatory cytokines (in particular IL8, interferon γ [IFNγ], and tumor necrosis factor α). This inflammatory signature was diminished in early-stage CLL (reduced IL8 and IFNγ levels, IL8 signaling pathway, and monocytic HLA-DR expression compared with MBL), especially in those patients with mutations in IGHV genes. Additionally, CD4⁺ T cells of MBL and early-stage CLL exhibited a similar upregulation of Th1 and cytotoxic genes and expanded CXCR3⁺ and perforin⁺ CD4⁺ T cells, as well as PD1⁺ CD4⁺ T cells, compared with controls. Cell culture assays disclosed tumor-supporting effects of monocytes similarly observed in MBL and early-stage CLL. These novel findings reveal differences in the inflammatory environment between MBL and CLL, highlighting an active role for antigen stimulation in the very early stages of the disease, potentially related to malignant B-cell transformation.

Alteration in TNFα mediates impaired antigen-specific humoral responses in sepsis survivors

Sepsis survivors show impaired responsiveness to antigen (Ag), which is linked to increased susceptibility to infection. Using the cecal ligation and puncture (CLP) model of sepsis, we showed that CLP surviving mice have a reduced antibody response to the T-dependent Ag, NP-CGG, compared to mice that underwent a sham procedure, but an intact response to the T-independent Ag, NP-Ficoll. CLP mice have reduced TNFα levels due to sustained vagus nerve activity. We hypothesized that reduced TNFα production might lead to disruption in follicular dendritic cell (FDC) function and impaired germinal center (GC) responses. FDCs play a key role in GC responses and TNFα is critical for FDC clustering and maturation. Immunofluorescence staining in spleens showed a reduced number of FDC clusters and reduced binding of immune complexes on FDCs in CLP mice compared to sham mice. NP-specific GC B cells sorted from CLP mice immunized with NP-CGG exhibit reduced TNFα, AICDA, and BCL6 mRNA expression compared to sham mice. To confirm the role of the vagus nerve in impaired FDC clusters, CLP mice were subjected to bilateral subdiaphragmatic vagotomy 2 weeks post-CLP. These mice exhibit increased anti-NP IgG levels in response to immunization with NP-CGG compared to non-vagotomized CLP mice. FDC are radioresistant cells; therefore, we lethally irradiated sham and CLP mice and reconstituted them with bone marrow cells from naive mice that never experienced sepsis. CLP mice still show an impaired Ag-specific response confirming involvement of FDCs and vagus nerve signals. In summary, our data suggest that altered vagus nerve activity, low TNFα, and disruption in FDC function contributes to reduced Ag-specific humoral responses in sepsis survivors.

Constitutive Vagus Nerve Activation Modulates Immune Suppression in Sepsis Survivors

Patients surviving a septic episode exhibit persistent immune impairment and increased mortality due to enhanced vulnerability to infections. In the present study, using the cecal ligation and puncture (CLP) model of polymicrobial sepsis, we addressed the hypothesis that altered vagus nerve activity contributes to immune impairment in sepsis survivors. CLP-surviving mice exhibited less TNFα in serum following administration of LPS, a surrogate for an infectious challenge, than control-operated (control) mice. To evaluate the role of the vagus nerve in the diminished response to LPS, mice were subjected to bilateral subdiaphragmatic vagotomy at 2 weeks post-CLP. CLP-surviving vagotomized mice exhibited increased serum and tissue TNFα levels in response to LPS-challenge compared to CLP-surviving, non-vagotomized mice. Moreover, vagus nerve stimulation in control mice diminished the LPS-induced TNFα responses while having no effect in CLP mice, suggesting constitutive activation of vagus nerve signaling in CLP-survivors. The percentage of splenic CD4⁺ ChAT-EGFP⁺ T cells that relay vagus signals to macrophages was increased in CLP-survivors compared to control mice, and vagotomy in CLP-survivors resulted in a reduced percentage of ChAT-EGFP⁺ cells. Moreover, CD4 knockout CLP-surviving mice exhibited an enhanced LPS-induced TNFα response compared to wild-type mice, supporting a functional role for CD4⁺ ChAT⁺ T cells in mediating inhibition of LPS-induced TNFα responses in CLP-survivors. Blockade of the cholinergic anti-inflammatory pathway with methyllcaconitine, an α7 nicotinic acetylcholine receptor antagonist, restored LPS-induced TNFα responses in CLP-survivors. Our study demonstrates that the vagus nerve is constitutively active in CLP-survivors and contributes to the immune impairment.

Vagal tonic activity modulates immune suppression in sepsis survivors

Sepsis survivors exhibit persistent immune dysfunction and compromised quality of life with premature mortality due to increased vulnerability to infections. Previously we demonstrated in a cecal ligation and puncture (CLP) model, sepsis survivors had a reduced TNFα response to LPS-challenge in vivo. The vagus nerve is known to modulate TNFα production. To evaluate the role of the vagus nerve in the diminished TNFα production, sepsis-surviving mice were subjected to bilateral subdiaphragmatic vagotomy 2 weeks post-CLP. CLP-surviving vagotomized mice exhibit increased (p<0.05) TNFα levels in response to LPS-challenge 4 weeks post surgery compared to CLP. Moreover, vagus nerve stimulation in sham mice dampened (p<0.05) the LPS-induced TNFα response while it had no effect in CLP-surviving mice; suggesting that vagus nerve signaling is constitutively active in CLP-sepsis survivors. To identify whether there was an alteration in the number of acetylcholine-producing T cells that relay the vagus signal to splenic macrophages, we used ChAT-EGFP mice. Our findings show that the frequency of splenic ChAT-EGFP+ cells among memory CD4+CD44highCD62LlowT cells is increased (p<0.001) in CLP-surviving mice compared to sham, and vagotomy in these mice resulted in decreased (p<0.01) frequency of ChAT-EGFP+ cells, buttressing the conclusion that the vagus nerve is constitutively firing action potentials to activate more ChAT+ T cells. Methyllycaconitine, the α7 nicotinic acetylcholine receptor antagonist, increased (p<0.01) LPS-induced TNFα secretion in CLP-surviving mice compared to saline treated-CLP. In summary, our study demonstrates that altered vagus nerve activity contributes to the immune impairment in sepsis survivors.

Immunization Elicits Antigen-Specific Antibody Sequestration in Dorsal Root Ganglia Sensory Neurons

The immune and nervous systems are two major organ systems responsible for host defense and memory. Both systems achieve memory and learning that can be retained, retrieved, and utilized for decades. Here, we report the surprising discovery that peripheral sensory neurons of the dorsal root ganglia (DRGs) of immunized mice contain antigen-specific antibodies. Using a combination of rigorous molecular genetic analyses, transgenic mice, and adoptive transfer experiments, we demonstrate that DRGs do not synthesize these antigen-specific antibodies, but rather sequester primarily IgG1 subtype antibodies. As revealed by RNA-seq and targeted quantitative PCR (qPCR), dorsal root ganglion (DRG) sensory neurons harvested from either naïve or immunized mice lack enzymes (i.e., RAG1, RAG2, AID, or UNG) required for generating antibody diversity and, therefore, cannot make antibodies. Additionally, transgenic mice that express a reporter fluorescent protein under the control of Igγ1 constant region fail to express Ighg1 transcripts in DRG sensory neurons. Furthermore, neural sequestration of antibodies occurs in mice rendered deficient in neuronal Rag2, but antibody sequestration is not observed in DRG sensory neurons isolated from mice that lack mature B cells [e.g., Rag1 knock out (KO) or μMT mice]. Finally, adoptive transfer of Rag1-deficient bone marrow (BM) into wild-type (WT) mice or WT BM into Rag1 KO mice revealed that antibody sequestration was observed in DRG sensory neurons of chimeric mice with WT BM but not with Rag1-deficient BM. Together, these results indicate that DRG sensory neurons sequester and retain antigen-specific antibodies released by antibody-secreting plasma cells. Coupling this work with previous studies implicating DRG sensory neurons in regulating antigen trafficking during immunization raises the interesting possibility that the nervous system collaborates with the immune system to regulate antigen-mediated responses.

MFG-E8-derived peptide attenuates adhesion and migration of immune cells to endothelial cells

Milk fat globule-epidermal growth factor-factor 8 (MFG-E8) plays an immunomodulatory role in inflammatory diseases. MFG-E8-derived short peptide (MSP68) greatly reduces neutrophil infiltration and injury in the lung during sepsis. In this study, we examined the effect of MSP68 on chemotaxis of various immune cells and its regulatory mechanism. Bone marrow-derived neutrophils (BMDNs) from C57BL/6 mice, human monocyte THP-1 cell line, and human T lymphocyte Jurkat cell line were used for adhesion and migration assays using a Transwell method in the presence of MSP68. Treatment with MSP68 significantly inhibited the BMDN and THP-1 cell but not Jurkat cell adhesion on the TNF-α-stimulated pulmonary artery endothelial cell (PAEC) monolayer dose-dependently. MSP68 also significantly reduced BMDN adhesion on VCAM-1-coated wells dose dependently. Surface plasmon resonance (SPR) analysis revealed that MSP68 efficiently recognized integrin α₄β₁ (receptor for VCAM-1) at the dissociation constant (K_D) of 1.53 × 10^-7 M. These findings implicate that MSP68 prevents neutrophil adhesion to the activated endothelial cells by interfering with the binding between integrin α₄β₁ on neutrophils and VCAM-1 on endothelial cells. Moreover, MSP68 significantly attenuated the migration of BMDN and THP-1 cells but not Jurkat cells to their chemoattractants. Pretreatment with MSP68 inhibited the transmigration of BMDNs across the PAECs toward chemoattractants, fMLP, MIP-2, and complement fragment 5a (C5a) dose-dependently. Finally, we identified that the activation of p38 MAPK in BMDNs by fMLP was inhibited by MSP68. Thus, MSP68 attenuates extravasation of immune cells through the endothelial cell lining into inflamed tissue, implicating MSP68 to be a novel, therapeutic agent for inflammatory diseases caused by excessive immune cell infiltration.

Use of RNA-seq to identify cardiac genes and gene pathways differentially expressed between dogs with and without dilated cardiomyopathy

OBJECTIVE To identify cardiac tissue genes and gene pathways differentially expressed between dogs with and without dilated cardiomyopathy (DCM). ANIMALS 8 dogs with and 5 dogs without DCM. PROCEDURES Following euthanasia, samples of left ventricular myocardium were collected from each dog. Total RNA was extracted from tissue samples, and RNA sequencing was performed on each sample. Samples from dogs with and without DCM were grouped to identify genes that were differentially regulated between the 2 populations. Overrepresentation analysis was performed on upregulated and downregulated gene sets to identify altered molecular pathways in dogs with DCM. RESULTS Genes involved in cellular energy metabolism, especially metabolism of carbohydrates and fats, were significantly downregulated in dogs with DCM. Expression of cardiac structural proteins was also altered in affected dogs. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that RNA sequencing may provide important insights into the pathogenesis of DCM in dogs and highlight pathways that should be explored to identify causative mutations and develop novel therapeutic interventions.

NF-κB activation is cell type-specific in the heart

Viral myocarditis is common and can progress to cardiac failure. Cardiac cell pro-inflammatory responses are critical for viral clearance, however sustained inflammatory responses contribute to cardiac damage. The transcription factor NF-κB regulates expression of many pro-inflammatory cytokines, but basal and induced activation of NF-κB in different cardiac cell types have not been compared. Here, we used primary cultures of cardiac myocytes and cardiac fibroblasts to identify cardiac cell type-specific events. We show that while viral infection readily stimulates activation of NF-κB in cardiac fibroblasts, cardiac myocytes are largely recalcitrant to activation of NF-κB. Moreover, we show that cardiac myocyte subpopulations differ in their NF-κB subcellular localization and identify the cis-Golgi as a cardiac myocyte-specific host compartment. Together, results indicate that NF-κB-dependent signaling in the heart is cardiac cell type-specific, likely reflecting mechanisms that have evolved to balance responses that can be either protective or damaging to the heart.

Identification of Iguratimod as an Inhibitor of Macrophage Migration Inhibitory Factor (MIF) with Steroid-sparing Potential

Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine that has been implicated in a broad range of inflammatory and oncologic diseases. MIF is unique among cytokines in terms of its release profile and inflammatory role, notably as an endogenous counter-regulator of the anti-inflammatory effects of glucocorticoids. In addition, it exhibits a catalytic tautomerase activity amenable to the design of high affinity small molecule inhibitors. Although several classes of these compounds have been identified, biologic characterization of these molecules remains a topic of active investigation. In this study, we used in vitro LPS-driven assays to characterize representative molecules from several classes of MIF inhibitors. We determined that MIF inhibitors exhibit distinct profiles of anti-inflammatory activity, especially with regard to TNFα. We further investigated a molecule with relatively low anti-inflammatory activity, compound T-614 (also known as the anti-rheumatic drug iguratimod), and found that, in addition to exhibiting selective MIF inhibition in vitro and in vivo, iguratimod also has additive effects with glucocorticoids. Furthermore, we found that iguratimod synergizes with glucocorticoids in attenuating experimental autoimmune encephalitis, a model of multiple sclerosis. Our work identifies iguratimod as a valuable new candidate for drug repurposing to MIF-relevant diseases, including multiple sclerosis.

Dysfunctional expansion of immature granulocytes in sepsis survivors

Sepsis is one of the leading causes of death worldwide. Surprisingly, increased mortality persists for years in sepsis survivors. This project investigated the contribution of myeloid cells to immune impairment in sepsis surviving mice. Sepsis was induced by cecal ligation and puncture (CLP). Sepsis survivors (2 weeks post-surgery) had significant increases in the CD11b+ Ly6Chigh and CD11b+ Ly6Clow myeloid populations in spleen, bone marrow and blood compared to controls. The expanded CD11b+ Ly6C populations in survivors were F4/80 negative. More CD11b+ Ly6C cells expressed the chemokine receptors CX3CR1 and CCR2, and the adhesion molecule CD62L. CD11b+ Ly6C populations in survivors also had higher levels of the mannose receptor CD206, Mer tyrosine kinase and the inhibitory collagen receptor LAIR-1; they appeared to be M2 like macrophages with presumed immune suppressive activity. Approximately 12% of the CD11b+Ly6Chigh population were CD115+ monocytes/macrophages, while the CD11b+ Ly6Clow comprised mainly immature granulocytes. CD11b+ Ly6Clow granulocytes in sepsis survivors had significantly reduced phagocytic activity compared to controls. A significant reduction in CD11b+ Ly6Clow granulocytes after LPS treatment was observed in controls but not survivors. Importantly, survivors had diminished serum production of TNF in response to endotoxin challenge, even though CD11b+ Ly6C granulocytes from the same mice produced comparable intracellular levels of TNF. In summary, our data indicate impaired cell exit and cytokine secretion, which is in part due to altered cell surface properties. This dysfunctional expansion of immature granulocytes may contribute to the impaired immune response in sepsis survivors.

Generating primary cultures of murine cardiac myocytes and cardiac fibroblasts to study viral myocarditis

Viruses can induce direct damage to cardiac myocytes and cardiac fibroblasts resulting in myocarditis and impaired cardiac function. Cardiac myocytes and cardiac fibroblasts display different capacities to support viral infection and generate a protective antiviral response. This chapter provides detailed protocols for generation and characterization of primary cultures of murine cardiac myocytes and cardiac fibroblasts, offering a powerful tool to probe cell type-specific responses that determine protection against viral myocarditis.

CXCL10 and its receptor CXCR3 regulate synovial fibroblast invasion in rheumatoid arthritis

OBJECTIVE

CXCL10 is expressed in increased levels in highly invasive fibroblast-like synoviocytes (FLS) from arthritic DA rats and from patients with rheumatoid arthritis (RA). This study was undertaken to analyze the role of CXCL10 and its receptor CXCR3 in regulation of the invasive properties of FLS.

METHODS

FLS were isolated from synovial tissue of RA patients and from DA rats and arthritis-resistant DA.F344(Cia5d) rats with pristane-induced arthritis. We used an in vitro model of invasion through Matrigel, which has been shown to correlate with articular damage in RA and in rat arthritis. FLS were cultured in the presence or absence of CXCL10, anti-CXCR3 antibody, or the CXCR3 inhibitor AMG487 and then studied for invasion, matrix metalloproteinase (MMP) production (MMPs 1-3), intracellular calcium influx, and cell morphology.

RESULTS

DA rat FLS produced higher levels of CXCL10 compared with minimally invasive FLS from DA.F344(Cia5d) rats. CXCL10 treatment increased the invasiveness of FLS from DA.F344(Cia5d) rats by 2-fold, and this increase was blocked by anti-CXCR3. Both anti-CXCR3 and AMG487 reduced invasiveness of FLS from DA rats, by as much as 77%. AMG487 significantly reduced invasiveness of RA FLS (by 58%). CXCR3 blockade reduced levels of MMP-1 by 65%, inhibited receptor signaling (64-100% reduction in intracellular calcium influx), and interfered with actin cytoskeleton reorganization and lamellipodia formation in FLS from rats and RA patients.

CONCLUSION

We describe and characterize a new autocrine/paracrine role of CXCL10/CXCR3 in the regulation of FLS invasion in rats with arthritis and in RA patients. These observations suggest that the CXCL10/CXCR3 axis is a potential new target for therapies aimed at reducing FLS invasion and its associated joint damage and pannus invasion and destruction in RA.

Th17 and non-Th17 interleukin-17-expressing cells in chronic lymphocytic leukemia: delineation, distribution, and clinical relevance

BACKGROUND

The levels and clinical relevance of Th17 cells and other interleukin-17-producing cells have not been analyzed in chronic lymphocytic leukemia. The objective of this study was to quantify blood and tissue levels of Th17 and other interleukin-17-producing cells in patients with this disease and correlate blood levels with clinical outcome.

DESIGN AND METHODS

Intracellular interleukin-17A was assessed in blood and splenic mononuclear cells from patients with chronic lymphocytic leukemia and healthy subjects using flow cytometry. Interleukin-17A-producing cells were analyzed in formalin-fixed, paraffin-embedded spleen and lymph node sections using immunohistochemistry and immunofluorescence.

RESULTS

The absolute numbers of Th17 cells in peripheral blood mononuclear cells and the percentages of Th17 cells in spleen cell suspensions were higher in patients with chronic lymphocytic leukemia than in healthy subjects; in six out of eight paired chronic lymphocytic leukemia blood and spleen sample comparisons, Th17 cells were enriched in spleen suspensions. Circulating Th17 levels correlated with better prognostic markers and longer overall survival of the patients. Two "non-Th17" interleukin-17-expressing cells were identified in chronic lymphocytic leukemia spleens: proliferating cells of the granulocytic lineage and mature mast cells. Granulocytes and mast cells in normal spleens did not express interleukin-17. Conversely, both chronic lymphocytic leukemia and healthy lymph nodes contained similar numbers of interleukin-17+ mast cells as well as Th17 cells.

CONCLUSIONS

Th17 cells are elevated in chronic lymphocytic leukemia patients with better prognostic markers and correlate with longer survival. Furthermore, non-Th17 interleukin-17A-expressing cells exist in chronic lymphocytic leukemia spleens as maturing granulocytes and mature mast cells, suggesting that the microenvironmental milieu in leukemic spleens promotes the recruitment and/or expansion of Th17 and other IL-17-expressing cells. The pathophysiology of Th17 and non-Th17-interleukin-producing cells in chronic lymphocytic leukemia and their distributions and roles in this disease merit further study.

CXCL10 and its receptor CXCR3 regulate synovial fibroblast invasion in rheumatoid arthritis

OBJECTIVE

CXCL10 is expressed in increased levels in highly invasive fibroblast-like synoviocytes (FLS) from arthritic DA rats and from patients with rheumatoid arthritis (RA). This study was undertaken to analyze the role of CXCL10 and its receptor CXCR3 in regulation of the invasive properties of FLS.

METHODS

FLS were isolated from synovial tissue of RA patients and from DA rats and arthritis-resistant DA.F344(Cia5d) rats with pristane-induced arthritis. We used an in vitro model of invasion through Matrigel, which has been shown to correlate with articular damage in RA and in rat arthritis. FLS were cultured in the presence or absence of CXCL10, anti-CXCR3 antibody, or the CXCR3 inhibitor AMG487 and then studied for invasion, matrix metalloproteinase (MMP) production (MMPs 1-3), intracellular calcium influx, and cell morphology.

RESULTS

DA rat FLS produced higher levels of CXCL10 compared with minimally invasive FLS from DA.F344(Cia5d) rats. CXCL10 treatment increased the invasiveness of FLS from DA.F344(Cia5d) rats by 2-fold, and this increase was blocked by anti-CXCR3. Both anti-CXCR3 and AMG487 reduced invasiveness of FLS from DA rats, by as much as 77%. AMG487 significantly reduced invasiveness of RA FLS (by 58%). CXCR3 blockade reduced levels of MMP-1 by 65%, inhibited receptor signaling (64-100% reduction in intracellular calcium influx), and interfered with actin cytoskeleton reorganization and lamellipodia formation in FLS from rats and RA patients.

CONCLUSION

We describe and characterize a new autocrine/paracrine role of CXCL10/CXCR3 in the regulation of FLS invasion in rats with arthritis and in RA patients. These observations suggest that the CXCL10/CXCR3 axis is a potential new target for therapies aimed at reducing FLS invasion and its associated joint damage and pannus invasion and destruction in RA.

Does maternal feeding restriction lead to childhood obesity in a prospective cohort study?

BACKGROUND

Some studies show that greater parental control over children's eating habits predicts later obesity, but it is unclear whether parents are reacting to infants who are already overweight.

OBJECTIVE

To examine the longitudinal association between maternal feeding restriction at age 1 and body mass index (BMI) at age 3 and the extent to which the association is explained by weight for length (WFL) at age 1.

METHODS

We studied 837 mother-infant pairs from a prospective cohort study. The main exposure was maternal feeding restriction at age 1, defined as agreeing or strongly agreeing with the following question: "I have to be careful not to feed my child too much." We ran multivariable linear regression models before and after adjusting for WFL at age 1. All models were adjusted for parental and child sociodemographic characteristics.

RESULTS

100 (12.0%) mothers reported feeding restriction at age 1. Mean (SD) WFL z-score at age 1 was 0.32 (1.01), and BMI z-score at age 3 was 0.43 (1.01). Maternal feeding restriction at age 1 was associated with higher BMI z-score at age 3 before (β 0.26 (95% CI 0.05 to 0.48)) but not after (β 0.00 (95% CI -0.17 to 0.18)) adjusting for WFL z-score at age 1. Each unit of WFL z-score at age 1 was associated with an increment of 0.57 BMI z-score units at age 3 (95% CI 0.51 to 0.62).

CONCLUSIONS

We found that maternal feeding restriction was associated with children having a higher BMI at age 3 before, but not after, adjusting for WFL at age 1. One potential reason may be that parents restrict the food intake of infants who are already overweight.

Proteomic analysis reveals virus-specific Hsp25 modulation in cardiac myocytes

Viruses frequently infect the heart but clinical myocarditis is rare, suggesting that the cardiac antiviral response is uniquely effective. Indeed, the Type I interferon (IFN) response is cardiac cell-type specific and provides one integrated network of protection for the heart. Here, a proteomic approach was used to identify additional proteins that may be involved in the cardiac antiviral response. Reovirus-induced murine myocarditis reflects direct viral damage to cardiac cells and offers an excellent system for study. Primary cultures of murine cardiac myocytes were infected with myocarditic or nonmyocarditic reovirus strains, and whole cell lysates were compared by two-dimensional difference gel electrophoresis (2D-DIGE) and matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF/TOF) tandem mass spectrometry. Results were quantitative and reproducible and demonstrated that whole proteome changes clustered according to viral pathogenic phenotype. Moreover, the data suggest that the heat shock protein Hsp25 is modulated differentially by myocarditic and nonmyocarditic reoviruses and may play a role in the cardiac antiviral response. Members of seven virus families modulate Hsp25 or Hsp27 expression in a variety of cell types, suggesting that Hsp25 participation in the antiviral response may be widespread. However, results here provide the first evidence for a virus-induced decrease in Hsp25/27 and suggest that viruses may have evolved a mechanism to subvert this protective response, as they have for IFN.

Rotavirus and reovirus modulation of the interferon response

The mammalian reoviruses and rotaviruses have evolved specific mechanisms to evade the Type I interferon (IFN) antiviral response. Rotavirus likely represses the IFN response by at least 4 mechanisms. First, the rotavirus protein NSP1, most likely functioning as an E3 ligase, can induce proteasome-dependent degradation of the transcription factors IRF3, IRF5, and IRF7 to prevent their induction of IFN. Second, NSP1 can induce proteasome-dependent degradation of the ubiquitin ligase complex protein beta-TrCP, resulting in stabilization of I kappaB and concomitant failure of virus to activate NF-kappaB for induction of IFN. Third, rotavirus may sequester NF-kappaB in viroplasms. And fourth, rotavirus can prevent STAT1 and STAT2 nuclear translocation. The predominant mechanism for rotavirus inhibition of the IFN response is likely both rotavirus strain-specific and cell type-specific. The mammalian reoviruses also display strain-specific differences in their modulation of the IFN response. Reovirus activates RIG-I and IPS-1 for phosphorylation of IRF3. Reovirus-induced activation of MDA5 also participates in induction if IFN-beta, perhaps through activation of NF-kappaB. Reovirus likely inhibits the IFN response by at least 3 virus strain-specific mechanisms. First, the reovirus mu2 protein can induce an unusual nuclear accumulation of IRF9 and repress IFN-stimulated gene (ISG) expression, most likely by disrupting IRF9 function as part of the heterotrimeric transcription factor complex, ISGF3. Second, the reovirus sigma 3 protein can bind dsRNA and prevent activation of the latent antiviral effector protein PKR. And third, genetic approaches have identified the reovirus lambda 2 and sigma 2 proteins in virus strain-specific modulation of the IFN response, but the significance remains unclear. In sum, members of the family Reoviridae have evolved a variety of mechanisms to subvert the host's innate protective response.

IFN-alpha expression and antiviral effects are subtype and cell type specific in the cardiac response to viral infection

The interferon-beta (IFN-beta) response is critical for protection against viral myocarditis in several mouse models, and IFN-alpha or -beta treatment is beneficial against human viral myocarditis. The IFN-beta response in cardiac myocytes and cardiac fibroblasts forms an integrated network for organ protection; however, the different IFN-alpha subtypes have not been studied in cardiac cells. We developed a quantitative RT-PCR assay that distinguishes between 13 highly conserved IFN-alpha subtypes and found that reovirus T3D induces five IFN-alpha subtypes in primary cardiac myocyte and fibroblast cultures: IFN-alpha1, -alpha2, -alpha4, -alpha5, and -alpha8/6. Murine IFN-alpha1, -alpha2, -alpha4, or -alpha5 treatment induced IRF7 and ISG56 and inhibited reovirus T3D replication in both cell types. This first investigation of IFN-alpha subtypes in cardiac cells for any virus demonstrates that IFN-alpha is induced in cardiac cells, that it is both subtype and cell type specific, and that it is likely important in the antiviral cardiac response.

Cholinergic agonists regulate JAK2/STAT3 signaling to suppress endothelial cell activation

The cholinergic anti-inflammatory pathway is a physiological mechanism that inhibits cytokine production and minimizes tissue injury during inflammation. Previous investigations revealed that cholinergic stimulation (via cholinergic agonists and vagus nerve stimulation) suppresses endothelial cell activation and leukocyte recruitment. The purpose of this study was to investigate the mechanisms by which cholinergic agonists (e.g., nicotine and GTS-21) regulate endothelial cell activation. Specifically, we examined the effects of cholinergic agonists on IL-6-mediated endothelial cell activation through the JAK2/STAT3 signaling pathway. Treatment of macrovascular human umbilical vein endothelial cells (HUVECs) and microvascular endothelial cells (MVECs) with the cholinergic agonists nicotine and GTS-21 significantly reduced IL-6-mediated monocyte chemoattractant protein-1 (MCP-1) production and ICAM-1 expression which are regulated through the JAK2/STAT3 pathway. We found that treatment of endothelial cells with cholinergic agonists significantly reduced STAT3 activation by phosphorylation and DNA binding. The inhibition of STAT3 phosphorylation was reversed by sodium orthovanadate, an inhibitor of tyrosine phosphatases, as well as by NSC-87877 suggesting a SHP1/2-dependent mechanism. Further investigations showed that cholinergic agonists reduced the phosphorylation of JAK2, an upstream component of the JAK2/STAT3 pathway. Finally, we observed that nicotine and GTS-21 treatment decreased levels of SOCS3 (suppressor of cytokine signaling; a regulator of the inflammatory activity of IL-6) in activated endothelial cells. These data demonstrate that cholinergic agonists suppress IL-6-mediated endothelial cell activation through the JAK2/STAT3 pathway. Our results have significant implications for better understanding the therapeutic potential of cholinergic agonists for treating IL-6 mediated inflammatory conditions.

Dysregulated chemokine receptor expression and chemokine-mediated cell trafficking in pediatric patients with ESRD

BACKGROUND AND OBJECTIVES

Children and adolescents with ESRD on dialysis are susceptible to serious bacterial infections (SBI). Chemokines and chemokine receptors play a critical role in modulating macrophage and neutrophil function. This study examined the hypothesis that expression and/or function of these molecules is dysregulated in patients with ESRD, contributing to leukocyte dysfunction. Design setting, participants, & measurements: Pediatric patients, age 6 mo to 18 yr, with ESRD treated with either hemodialysis or peritoneal dialysis were enrolled in this prospective, nontherapeutic study. Blood was collected for plasma chemokine levels, chemokine receptor profiling by flow cytometry, and functional chemotaxis studies on neutrophils and mononuclear cells.

RESULTS

ESRD in children was associated with reduced expression of the chemokine receptors CXCR1 and chemokine (C-C motif) receptor 2 (CCR2) on circulating neutrophils and monocytes, respectively. When ESRD patients were divided into two subgroups, those who were infection-free and those who had three or more SBI in the preceding year, the differences in chemokine receptor expression were statistically significant compared with control subjects only in those with recurrent infection. In addition to the effects of ESRD on baseline chemokine receptor expression, the hemodialysis procedure itself acutely lowered neutrophil CXCR1 and monocyte CCR2 expression. Furthermore, neutrophil and monocyte responsiveness to chemokine-mediated trafficking signals was impaired in all ESRD patients studied. This abnormality was independent of the level of chemokine receptor expression on the leukocytes.

CONCLUSIONS

The data presented in this study suggest that chemokine receptor dysregulation contributes to leukocyte dysfunction in patients with ESRD. This alteration is especially prominent in ESRD patients with recurrent infection.

Modulation of rat intestinal nuclear factor NF-kappaB by gum arabic

The objective of this study was to test the hypothesis that in an animal model of cathartic-induce intestinal dysfunction the proabsorptive effects of gum arabic (GA) could be associated with modulation of nuclear factor-kappaB (NF-kappaB) and with reduction of the inflammatory response caused by cathartics, as evidenced by intestinal mucosa cytokine production and gene expression. Juvenile male rats were given a phenolphthalein-magnesium citrate solution for 6 days, by itself or supplemented with either 10 or 20 g L(-1) GA, as a sole source of fluid. The controls given were tap water alone or with added 20 g L(-1) GA. The animals were euthanized and small-intestinal mucosa nuclear fractions and RNA were isolated. NF-kappaB p65 activity was highest after administration of cathartics, lowest in controls, and intermediate in GA-treated rats. Mucosal IL-1beta was overexpressed in tissues from cathartic-treated rats and from rats given high-GA solutions. Gene-array analysis revealed a complex pattern of gene regulation by cathartics which selectively upregulated several subfamilies of cytochrome P-450 family 2 genes. Co-administration of GA did not block this effect. These findings suggest that local anti-inflammatory effects on the small intestine could be obtained by administration of a nonabsorbable proteoglycan such as GA.

Functional analysis of Leishmania major cyclophilin

A potent immunosuppressive drug cyclosporin A (CsA) is known to inhibit human cell infection by the pathogenic protozoan parasite Leishmania major both in vitro and in vivo. The proposed mechanism of action involves CsA binding to Leishmania major-expressed cyclophilin and subsequent down-regulation of signaling events necessary for establishing productive infection. Recently, we identified a ubiquitously expressed membrane protein, CD147, as a signaling receptor for extracellular cyclophilins in mammalian cells. Here we demonstrate that, while being enzymatically active, the Leishmania cyclophilin, unlike its human homologue, does not interact with CD147 on the cell surface of target cells. CD147 facilitates neither Leishmania binding nor infection. Primary structure and biochemical analyses revealed that the parasite's cyclophilin is defective in heparan binding, an event required for signaling interaction between CD147 and human cyclophilin. When the heparan-binding motif was reconstituted in Leishmania cyclophilin, it regained the CD147-dependent signaling activity. These results underscore a critical role of cyclophilin-heparan interactions in CD147-mediated signaling events and argue against the role of Leishmania cyclophilin in parasite binding to target cells.

Retinoic acid-inducible gene-I and interferon-beta promoter stimulator-1 augment proapoptotic responses following mammalian reovirus infection via interferon regulatory factor-3

During viral infection, cells initiate antiviral responses to contain replication and inhibit virus spread. One protective mechanism involves activation of transcription factors interferon regulatory factor-3 (IRF-3) and NF-kappaB, resulting in secretion of the antiviral cytokine, interferon-beta. Another is induction of apoptosis, killing the host cell before virus disseminates. Mammalian reovirus induces both interferon-beta and apoptosis, raising the possibility that both pathways are initiated by a common cellular sensor. We show here that reovirus activates IRF-3 with kinetics that parallel the activation of NF-kappaB, a known mediator of reovirus-induced apoptosis. Activation of IRF-3 requires functional retinoic acid inducible gene-I and interferon-beta promoter stimulator-1, but these intracellular sensors are dispensable for activation of NF-kappaB. Interferon-beta promoter stimulator-1 and IRF-3 are required for efficient apoptosis following reovirus infection, suggesting a common mechanism of antiviral cytokine induction and activation of the cell death response.

The arthritis severity quantitative trait loci Cia4 and Cia6 regulate neutrophil migration into inflammatory sites and levels of TNF-alpha and nitric oxide

Neutrophils are required for the development of arthritis, and their migration into the synovial tissue coincides with the onset of clinical disease. Synovial neutrophil numbers also correlate with rheumatoid arthritis disease activity and severity. We hypothesized that certain arthritis severity genes regulate disease via the regulation of neutrophil migration into the joint. This hypothesis was tested in the synovial-like air pouch model injected with carrageenan using arthritis-susceptible DA and arthritis-resistant F344 rats. DA had nearly 3-fold higher numbers of exudate neutrophils compared with F344 (p < 0.001). Five DA.F344(QTL) strains congenic for severity loci and protected from autoimmune arthritis were studied. Only DA.F344(Cia4) (chromosome 7) and DA.F344(Cia6) (chromosome 8) congenics had significantly lower exudate neutrophil counts compared with DA. TNF-alpha levels were 2.5-fold higher in DA exudates as compared with F344 exudates, and that difference was accounted for by the Cia4 locus. Exudate levels of NO, a known inhibitor of neutrophil chemotaxis, were higher in F344, compared with DA, and that difference was accounted for by Cia6. This is the first time that non-MHC autoimmune arthritis loci are found to regulate three central components of the innate immune response implicated in disease pathogenesis, namely neutrophil migration into an inflammatory site, as well as exudate levels of TNF-alpha and NO. These observations underscore the importance of identifying the Cia4 and Cia6 genes, and suggest that they should generate useful novel targets for development of new therapies.

The arthritis severity quantitative trait locus Cia7 regulates neutrophil migration into inflammatory sites

Neutrophils are required for the development of arthritis in rodents, and are the predominant cell in the synovial fluid of active rheumatoid arthritis. We hypothesized that neutrophil migration into the inflammed joint is genetically regulated. In addition, this genetic regulation would be accounted for by one of the arthritis loci that we have previously identified in an intercross between arthritis-susceptible DA and arthritis-resistant ACI rats studied for collagen-induced arthritis. We used the synovial-like air pouch model injected with carrageenan, and tested DA, ACI, and four congenic strains. ACI exudates had a significantly lower number of neutrophils compared with DA. Transfer of DA alleles at Cia7 into the ACI background, as in ACI.DA(Cia7) congenics, was enough to increase exudate neutrophil numbers to levels identical to DA, and this locus accounted for the difference between parental strains. None of the other congenic intervals explained the differences in exudate neutrophil counts. In conclusion, we have identified a novel function for Cia7, and determined that it regulates neutrophil migration into a synovial-like inflammatory site. Our data revealed no intrinsic defect in neutrophil responses to chemotactic agents, and suggest that Cia7 regulates an as yet unidentified factor central to neutrophil recruitment into inflammed tissues.

Food behaviors and other strategies to prevent and treat pediatric overweight

OBJECTIVE

To summarize the evidence for the following six strategies to prevent or treat overweight among children: promoting breastfeeding, promoting physical activity, reducing TV/video viewing, increasing fruit and vegetable consumption, reducing sugar-sweetened drink consumption, and reducing portion sizes.

METHODS

Summarization of the relevant literature including review articles, relevant newly published work, the Institute of Medicine's Report on Preventing Childhood Obesity and the Surgeon General's Call to Action to Prevent and Decrease Overweight and Obesity, 2001. This is not a comprehensive review.

RESULTS

Evidence for the association between each strategy and overweight varies. For breastfeeding, physical activity, and TV viewing, there are large review studies. Breastfed children may have a small reduction in risk for overweight. Participation in physical activity may reduce the risk of overweight among school-aged children and adolescents. For preschool- and school-aged children, reducing TV viewing time may reduce their risk of overweight, but most studies report small significant associations. Evidence for an association between each dietary factor and overweight is limited and inconclusive. The biggest gaps in evidence are for the effectiveness of interventions using these strategies. The reviewed interventions based on increasing physical activity (n=7) were effective. Two randomized trials suggest that reducing TV viewing reduces overweight. No intervention studies were found that examined the effectiveness of changing fruit and vegetable consumption, sugar-sweetened drink consumption, or portion sizes. Further clarification of the effect of breastfeeding on obesity is needed.

CONCLUSIONS

These six strategies are reasonable ways to attempt prevention or treatment of overweight in children. Strength of the evidence varies by strategy. The key finding is that more applied research is needed to determine the effectiveness of these and other strategies.

Role of HMGB1 in apoptosis-mediated sepsis lethality

Severe sepsis, a lethal syndrome after infection or injury, is the third leading cause of mortality in the United States. The pathogenesis of severe sepsis is characterized by organ damage and accumulation of apoptotic lymphocytes in the spleen, thymus, and other organs. To examine the potential causal relationships of apoptosis to organ damage, we administered Z-VAD-FMK, a broad-spectrum caspase inhibitor, to mice with sepsis. We found that Z-VAD-FMK–treated septic mice had decreased levels of high mobility group box 1 (HMGB1), a critical cytokine mediator of organ damage in severe sepsis, and suppressed apoptosis in the spleen and thymus. In vitro, apoptotic cells activate macrophages to release HMGB1. Monoclonal antibodies against HMGB1 conferred protection against organ damage but did not prevent the accumulation of apoptotic cells in the spleen. Thus, our data indicate that HMGB1 production is downstream of apoptosis on the final common pathway to organ damage in severe sepsis.

Redox regulation of cyclophilin A by glutathionylation

Using redox proteomics techniques to characterize the thiol status of proteins in human T lymphocytes, we identified cyclophilin A (CypA) as a specifically oxidized protein early after mitogen activation. CypA is an abundantly expressed cytosolic protein, target of the immunosuppressive drug cyclosporin A (CsA), for which a variety of functions has been described. In this study, we could identify CypA as a protein undergoing glutathionylation in vivo. Using MALDI-MS we identified Cys52 and Cys62 as targets of glutathionylation in T lymphocytes, and, using bioinformatic tools, we defined the reasons for the susceptibility of these residues to the modification. In addition, we found by circular dichroism spectroscopy that glutathionylation has an important impact on the secondary structure of CypA. Finally, we suggest that glutathionylation of CypA may have biological implications and that CypA may play a key role in redox regulation of immunity.

Organ-specific roles for transcription factor NF-kappaB in reovirus-induced apoptosis and disease

Reovirus induces apoptosis in cultured cells and in vivo. In cell culture models, apoptosis is contingent upon a mechanism involving reovirus-induced activation of transcription factor NF-kappaB complexes containing p50 and p65/RelA subunits. To explore the in vivo role of NF-kappaB in this process, we tested the capacity of reovirus to induce apoptosis in mice lacking a functional nfkb1/p50 gene. The genetic defect had no apparent effect on reovirus replication in the intestine or dissemination to secondary sites of infection. In comparison to what was observed in wild-type controls, apoptosis was significantly diminished in the CNS of p50-null mice following reovirus infection. In sharp contrast, the loss of p50 was associated with massive reovirus-induced apoptosis and uncontrolled reovirus replication in the heart. Levels of IFN-beta mRNA were markedly increased in the hearts of wild-type animals but not p50-null animals infected with reovirus. Treatment of p50-null mice with IFN-beta substantially diminished reovirus replication and apoptosis, which suggests that IFN-beta induction by NF-kappaB protects against reovirus-induced myocarditis. These findings reveal an organ-specific role for NF-kappaB in the regulation of reovirus-induced apoptosis, which modulates encephalitis and myocarditis associated with reovirus infection.

Role of Rho family GTPases in CCR1- and CCR5-induced actin reorganization in macrophages

The beta-chemokines, MIP-1alpha/CCL3, MIP-1beta/CCL4, and RANTES/CCL5, play a critical role in the selective accumulation and activation of macrophages in inflamed tissues. Herein, we demonstrate that the binding of each of these beta-chemokines to their cognate receptors, CCR1 and CCR5, in either macrophages or in CCR1- or CCR5-transfected CHO cells, induced actin reorganization and the formation of lamellipodia that are characteristic of the activation of the Rho family GTPase, Rac. A dominant negative mutant of Rac, but not dominant negative mutants of RhoA or Cdc42, blocked MIP-1alpha-induced lamellipodia formation. Moreover, this MIP-1alpha-induced Rac activation and consequent lamellipodia formation is Gi- and phosphoinositide-3 kinase (PI3K)-mediated. Thus, Rac activation is critical for both CCR1- and CCR5-triggered signaling cascades mediating beta-chemokine-induced reorganization of the actin cytoskeleton, a process essential for effective recruitment and activation of macrophages in inflammation.

Cell surface expression of CD147/EMMPRIN is regulated by cyclophilin 60

CD147, also known as extracellular matrix metalloproteinase inducer, is a regulator of matrix metalloproteinase production and also serves as a signaling receptor for extracellular cyclophilins. Previously, we demonstrated that cell surface expression of CD147 is sensitive to cyclophilin-binding drug cyclosporin A, suggesting involvement of a cyclophilin in the regulation of intracellular transport of CD147. In this report, we identify this cyclophilin as cyclophilin 60 (Cyp60), a distinct member of the cyclophilin family of proteins. CD147 co-immunoprecipitated with Cyp60, and confocal immunofluorescent microscopy revealed intracellular co-localization of Cyp60 and CD147. This interaction with Cyp60 involved proline 211 of CD147, which was shown previously to be critical for interaction between CD147 and another cyclophilin, cyclophilin A, in solution. Mutation of this proline residue abrogated co-immunoprecipitation of CD147 and Cyp60 and reduced surface expression of CD147 on the plasma membrane. Suppression of Cyp60 expression using RNA interference had an effect similar to that of cyclosporin A: reduction of cell surface expression of CD147. These results suggest that Cyp60 plays an important role in the translocation of CD147 to the cell surface. Therefore, Cyp60 may present a novel target for therapeutic interventions in diseases where CD147 functions as a pathogenic factor, such as cancer, human immunodeficiency virus infection, or rheumatoid arthritis.

Cholinergic stimulation blocks endothelial cell activation and leukocyte recruitment during inflammation

Endothelial cell activation plays a critical role in regulating leukocyte recruitment during inflammation and infection. Based on recent studies showing that acetylcholine and other cholinergic mediators suppress the production of proinflammatory cytokines via the α7 nicotinic acetylcholine receptor (α7 nAChR) expressed by macrophages and our observations that human microvascular endothelial cells express the α7 nAChR, we examined the effect of cholinergic stimulation on endothelial cell activation in vitro and in vivo. Using the Shwartzman reaction, we observed that nicotine (2 mg/kg) and the novel cholinergic agent CAP55 (12 mg/kg) inhibit endothelial cell adhesion molecule expression. Using endothelial cell cultures, we observed the direct inhibitory effects of acetylcholine and cholinergic agents on tumor necrosis factor (TNF)-induced endothelial cell activation. Mecamylamine, an nAChR antagonist, reversed the inhibition of endothelial cell activation by both cholinergic agonists, confirming the antiinflammatory role of the nAChR cholinergic pathway. In vitro mechanistic studies revealed that nicotine blocked TNF-induced nuclear factor–κB nuclear entry in an inhibitor κB (IκB)α- and IκBɛ-dependent manner. Finally, with the carrageenan air pouch model, both vagus nerve stimulation and cholinergic agonists significantly blocked leukocyte migration in vivo. These findings identify the endothelium, a key regulator of leukocyte trafficking during inflammation, as a target of anti-inflammatory cholinergic mediators.

Macrophage inflammatory protein 1alpha inhibits postentry steps of human immunodeficiency virus type 1 infection via suppression of intracellular cyclic AMP

Primary isolates of human immunodeficiency virus type 1 (HIV-1) predominantly use chemokine receptor CCR5 to enter target cells. The natural ligands of CCR5, the beta-chemokines macrophage inflammatory protein 1alpha (MIP-1alpha), MIP-1beta, and RANTES, interfere with HIV-1 binding to CCR5 receptors and decrease the amount of virions entering cells. Although the inhibition of HIV-1 entry by beta-chemokines is well documented, their effects on postentry steps of the viral life cycle and on host cell components that control the outcome of infection after viral entry are not well defined. Here, we show that all three beta-chemokines, and MIP-1alpha in particular, inhibit postentry steps of the HIV-1 life cycle in primary lymphocytes, presumably via suppression of intracellular levels of cyclic AMP (cAMP). Productive HIV-1 infection of primary lymphocytes requires cellular activation. Cell activation increases intracellular cAMP, which is required for efficient synthesis of proviral DNA during early steps of viral infection. Binding of MIP-1alpha to cognate receptors decreases activation-induced intracellular cAMP levels through the activation of inhibitory G proteins. Furthermore, inhibition of one of the downstream targets of cAMP, cAMP-dependent PKA, significantly inhibits synthesis of HIV-1-specific DNA without affecting virus entry. These data reveal that beta-chemokine-mediated inhibition of virus replication in primary lymphocytes combines inhibitory effects at the entry and postentry levels and imply the involvement of beta-chemokine-induced signaling in postentry inhibition of HIV-1 infection.

Regulation of CD147 Cell Surface Expression

CD147, also known as extracellular matrix metalloproteinase inducer, is a regulator of matrix metalloproteinase production and serves as a signaling receptor for extracellular cyclophilins. Here we demonstrate that the cell surface expression of CD147 is regulated by cyclophilins via the transmembrane domain of CD147. Solution binding experiments demonstrated that the transmembrane domain was both necessary and sufficient for CD147 binding to cyclophilin A (CypA). Treatment with cyclosporin A significantly reduced surface expression of CD147 and of CD8-CD147 fusion protein carrying the extracellular domain of CD8 fused to the transmembrane and cytoplasmic domains of CD147, but did not affect expression of CD8. Peptide binding studies demonstrated specific interaction between CypA and the proline-containing peptide from the CD147 transmembrane domain. Mutation of this proline residue reduced binding of CD147-derived peptides to CypA and also diminished transport of CD147 to the plasma membrane without reducing the total level of CD147 expression. These results suggest involvement of a cyclophilin-related protein in CD147 cell surface expression and provide molecular details for regulation of CD147 trafficking by cyclophilins.

Basal and reovirus-induced beta interferon (IFN-beta) and IFN-beta-stimulated gene expression are cell type specific in the cardiac protective response

Viral myocarditis is an important human disease, with a wide variety of viruses implicated. Cardiac myocytes are not replenished yet are critical for host survival and thus may have a unique response to infection. Previously, we determined that the extent of reovirus induction of beta interferon (IFN-beta) and IFN-beta-mediated protection in primary cardiac myocyte cultures was inversely correlated with the extent of reovirus-induced cardiac damage in a mouse model. Surprisingly, and in contrast, the IFN-beta response did not determine reovirus replication in skeletal muscle cells. Here we compared the IFN-beta response in cardiac myocytes to that in primary cardiac fibroblast cultures, a readily replenished cardiac cell type. We compared basal and reovirus-induced expression of IFN-beta, IRF-7 (an interferon-stimulated gene [ISG] that further induces IFN-beta), and another ISG (561) in the two cell types by using real-time reverse transcription-PCR. Basal IFN-beta, IRF-7, and 561 expression was higher in cardiac myocytes than in cardiac fibroblasts. Reovirus T3D induced greater expression of IFN-beta in cardiac myocytes than in cardiac fibroblasts but equivalent expression of IRF-7 and 561 in the two cell types (though fold induction for IRF-7 and 561 was higher in fibroblasts than in myocytes because of the differences in basal expression). Interestingly, while reovirus replicated to equivalent titers in cardiac myocytes and cardiac fibroblasts, removal of IFN-beta resulted in 10-fold-greater reovirus replication in the fibroblasts than in the myocytes. Together the data suggest that the IFN-beta response controls reovirus replication equivalently in the two cell types. In the absence of reovirus-induced IFN-beta, however, reovirus replicates to higher titers in cardiac fibroblasts than in cardiac myocytes, suggesting that the higher basal IFN-beta and ISG expression in myocytes may play an important protective role.

Ethanol blocks leukocyte recruitment and endothelial cell activation in vivo and in vitro

Immune system impairment and increased susceptibility to infection among alcohol abusers is a significant but not well-understood problem. We hypothesized that acute ethanol administration would inhibit leukocyte recruitment and endothelial cell activation during inflammation and infection. Using LPS and carrageenan air pouch models in mice, we found that physiological concentrations of ethanol (1-5 g/kg) significantly blocked leukocyte recruitment (50-90%). Because endothelial cell activation and immune cell-endothelial cell interactions are critical regulators of leukocyte recruitment, we analyzed the effect of acute ethanol exposure on endothelial cell activation in vivo using the localized Shwartzman reaction model. In this model, ethanol markedly suppressed leukocyte accumulation and endothelial cell adhesion molecule expression in a dose-dependent manner. Finally, we examined the direct effects of ethanol on endothelial cell activation and leukocyte-endothelial cell interactions in vitro. Ethanol, at concentrations within the range found in human blood after acute exposure and below the levels that induce cytotoxicity (0.1-0.5%), did not induce endothelial cell activation, but significantly inhibited TNF-mediated endothelial cell activation, as measured by adhesion molecule (E-selectin, ICAM-1, VCAM-1) expression and chemokine (IL-8, MCP-1, RANTES) production and leukocyte adhesion in vitro. Studies exploring the potential mechanism by which ethanol suppresses endothelial cell activation revealed that ethanol blocked NF-kappaB nuclear entry in an IkappaBalpha-dependent manner. These findings support the hypothesis that acute ethanol overexposure may increase the risk of infection and inhibit the host inflammatory response, in part, by blocking endothelial cell activation and subsequent immune cell-endothelial cell interactions required for efficient immune cell recruitment.

Caspase inhibition protects against reovirus-induced myocardial injury in vitro and in vivo

Viral myocarditis is a disease with a high morbidity and mortality. The pathogenesis of this disease remains poorly characterized, with components of both direct virus-mediated and secondary inflammatory and immune responses contributing to disease. Apoptosis has increasingly been viewed as an important mechanism of myocardial injury in noninfectious models of cardiac disease, including ischemia and failure. Using a reovirus murine model of viral myocarditis, we characterized and targeted apoptosis as a key mechanism of virus-associated myocardial injury in vitro and in vivo. We demonstrated caspase-3 activation, in conjunction with terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling and annexin binding, in cardiac myocytes after myocarditic viral infection in vitro. We also demonstrated a tight temporal and geographical correlation between caspase-3 activation, histologic injury, and viral load in cardiac tissue after myocarditic viral infection in vivo. Two pharmacologic agents that broadly inhibit caspase activity, Q-VD-OPH and Z-VAD(OMe)-FMK, effectively inhibited virus-induced cellular death in vitro. The inhibition of caspase activity in vivo by the use of pharmacologic agents as well as genetic manipulation reduced virus-induced myocardial injury by 40 to 60% and dramatically improved survival in infected caspase-3-deficient animals. This study indicates that apoptosis plays a critical role in mediating cardiac injury in the setting of viral myocarditis and is the first demonstration that caspase inhibition may serve as a novel therapeutic strategy for this devastating disease.

PERITONEAL AND SYSTEMIC INFLAMMATORY MEDIATORS OF LAPAROSCOPIC BOWEL INJURY IN A RABBIT MODEL

PURPOSE

Unrecognized bowel injury following laparoscopy has a subtle and delayed clinical presentation compared with that after open surgery. We determined peritoneal and systemic immune function in laparoscopic and open bowel injury cases. We propose that laparoscopy does not activate immune responses to the same extent as open surgery.

MATERIALS AND METHODS

A total of 40 rabbits were divided into 4 groups. Two study groups were subjected to laparoscopic and open bowel injury, and 2 control groups underwent pneumoperitoneum and sham open surgery, respectively, without bowel injury. Animals were sacrificed 1 day, 3 days and 1 week postoperatively. Macroscopic and histological findings were analyzed. Peritoneal fluid, systemic white blood count (WBC) and differentials were done with a hemocytometer. Peritoneal fluid and serum interleukin (IL)-8 concentrations were measured by enzyme-linked immunosorbent assay.

RESULTS

Macroscopic and histological findings were indistinguishable in the 2 study groups. However, study groups demonstrated higher peritoneal WBCs than their respective controls at 1 and 3 days (p <0.05). Peritoneal WBC was lower in the laparoscopy than in the open study group at 3 days (p <0.05). There was a significant decrease in peritoneal lymphocytes and monocytes in the laparoscopic vs the open study group at 3 days. No differences were found in systemic WBC or differentials among all groups. Peritoneal IL-8 concentrations were higher in the laparoscopic bowel injury than in the laparoscopic control group at 1 and 3 days (p <0.05). However, there were no differences in peritoneal or serum IL-8 concentrations between both study groups.

CONCLUSIONS

Laparoscopic surgery seems to be unable to sustain peritoneal immune responses, which may mask reliable clinical signs and symptoms of peritonitis associated with bowel injury.