Human recombinant interleukin-38 suppresses inflammation in mouse models of local and systemic disease.

Interleukin (IL)-38 belongs to the IL-1 family and is part of the IL-36 subfamily due to its binding to the IL-36 Receptor (IL-1R6). In the current study, we assessed the anti-inflammatory properties of IL-38 in murine models of arthritis and systemic inflammation. First, the anti-inflammatory properties of mouse and human IL-38 precursors were compared to forms with a truncated N-terminus. In mouse bone marrow derived dendritic cells (BMDC), human and mouse IL-38 precursors with a truncation of the two N-terminal amino acids (3-152) suppressed LPS-induced IL-6. Recombinant human IL-38 (3-152) was further investigated for its immunomodulatory potential using four murine models of inflammatory disease: streptococcal cell wall (SCW)-induced arthritis, monosodium urate (MSU) crystal-induced arthritis, MSU crystal-induced peritonitis, and systemic endotoxemia. In each of these models IL-38 significantly reduced inflammation. In SCW and MSU crystal-induced arthritis, joint swelling, inflammatory cell influx, and synovial levels of IL-1ß, IL-6, and KC were reduced by 50% or greater. These suppressive properties of IL-38 in SCW-induced arthritis were independent of the anti-inflammatory co-receptor IL-1R8, as IL-38 reduced arthritis equally in IL-1R8 deficient and WT mice. In MSU crystal-induced peritonitis, IL-38 reduced hypothermia, while plasma IL-6 and KC and peritoneal KC levels were reduced by 65-70%. In the LPS endotoxemia model, IL-38 pretreatment reduced systemic IL-6, TNFα and KC. Furthermore, in ex vivo cultured bone marrow, LPS-induced IL-6, TNFα and KC were reduced by 75-90%. Overall, IL-38 exhibits broad anti-inflammatory properties in models of systemic and local inflammation and therefore may be an effective cytokine therapy.

Molecular mechanism of down-regulating adipogenic transcription factors in 3T3-L1 adipocyte cells by bioactive anti-adipogenic compounds.

Obesity is growing at an alarming rate, which is characterized by increased adipose tissue. It increases the probability of many health complications, such as diabetes, arthritis, cardiac disease, and cancer. In modern society, with a growing population of obese patients, several individuals have increased insulin resistance. Herbal medicines are known as the oldest method of health care treatment for obesity-related secondary health issues. Several traditional medicinal plants and their effective phytoconstituents have shown anti-diabetic and anti-adipogenic activity. Adipose tissue is a major site for lipid accumulation as well as the whole-body insulin sensitivity region. 3T3-L1 cell line model can achieve adipogenesis. Adipocyte characteristics features such as expression of adipocyte markers and aggregation of lipids are chemically induced in the 3T3-L1 fibroblast cell line. Differentiation of 3T3-L1 is an efficient and convenient way to obtain adipocyte like cells in experimental studies. Peroxisome proliferation activated receptor γ (PPARγ) and Cytosine-Cytosine-Adenosine-Adenosine-Thymidine/Enhancer-binding protein α (CCAAT/Enhancer-binding protein α or C/EBPα) are considered to be regulating adipogenesis at the early stage, while adiponectin and fatty acid synthase (FAS) is responsible for the mature adipocyte formation. Excess accumulation of these adipose tissues and lipids leads to obesity. Thus, investigating adipose tissue development and the underlying molecular mechanism is important in the therapeutical approach. This review describes the cellular mechanism of 3T3-L1 fibroblast cells on potential anti-adipogenic herbal bioactive compounds.

Prophylactic effects of probiotic Bifidobacterium spp. in the resolution of inflammation in arthritic rats.

In the present study, the modulatory effects of bifidobacterial spp. (Bifidobacterium breve NCIM 5671, Bifidobacterium longum NCIM 5672 and Bifidobacterium bifidum NCIM 5697) on adjuvant induced arthritis in rats were evaluated. Arthritis was induced in male Wistar rats by injecting 250 µg of Freund's adjuvant directly into the paw. Fifteen days before and 15 days after the induction of arthritis, suspended cultures of bifidobacteria (109 cfu/ml) were administered by oral gavage. Paw volume, bone mineral content, oxidative stress markers, antioxidant enzymes, cytokines, eicosanoids and expression of COX2, as well as bone hydrolytic enzymes, were assessed by RT PCR. Although piroxicam-treated groups (drug control) had better effects than bifidobacteria-treated groups, bifidobacteria probiotics administration exhibited significant (P < 0.05) prophylactic effects in terms of downregulating arthritis markers. Parameters including paw volume, bone mineral content, cytokines, and eicosanoids level were significantly (p < 0.05) modulated in bifidobacteria administered groups compared to arthritic control group. Among the three strains tested, B. breve NCIM 5671 exhibited superior prophylactic effects as assessed in the experimental rat model of arthritis. In conclusion, bifidobacteria probiotics administration can downregulate the markers of arthritis and hence can be a potential therapeutic regimen in the treatment of arthritis.

Conditioned Medium of Mesenchymal Stromal Cells: A New Class of Therapeutics.

Mesenchymal stromal cell (MSCs) represent a class of biologics with the prospects for employment as immunomodulatory, tissue-protective, and regenerative therapeutics. In parallel with cellular therapy, cell-free therapy based on MSC-secreted bioactive factors is being actively developed. MSCs secrete a variety of protein, peptide, RNA, and lipid mediators which can be concentrated, frozen, or even lyophilized without loss of activity, which gives them a certain advantage over cellular products requiring liquid nitrogen storage and infrastructure to revive frozen cells. This review (i) describes currently conducted clinical trials of cell-free products containing MSC secretome; (ii) summarizes main approaches to the generation and characterization of conditioned media concentrates and extracellular vesicle isolates; (iii) analyzes a variety of preclinical studies where effectiveness of secretome products has been shown; and (iv) summarizes current knowledge about secretome bioactive components obtained by analysis of in vivo models testing the therapeutic potential of the MSC secretome.

Self-Directed Walk With Ease Workplace Wellness Program - Montana, 2015-2017.

Arthritis occurs in 27% of adults in Montana, among whom 50% have activity limitations, 16% have social participation restrictions, and 23% have severe joint pain attributable to arthritis (1). Physical activity is beneficial in managing arthritis symptoms and in preventing other chronic diseases (2). Walk With Ease is a 6-week evidence-based physical activity program recommended by CDC to increase physical activity and help improve arthritis symptoms (3). In 2015, Walk With Ease was added to an ongoing workplace wellness program for Montana state employees; the results for five outcomes (minutes spent walking, engaging in other physical activity [including swimming, bicycling, other aerobic equipment use, and other aerobic exercise], stretching, pain, and fatigue) were analyzed by the Montana Department of Public Health and Human Services and CDC. Outcomes at baseline (pretest), 6 weeks after the program (posttest), and 6 months later (follow-up) were analyzed by self-reported arthritis status at the time the participant enrolled in the program. Significant increases (p<0.05) in the mean number of minutes spent per week walking and engaging in other physical activity were observed among participants with and without arthritis at the 6-week posttest. Time spent stretching did not change significantly at posttest for either group. Mean pain levels among participants without arthritis increased significantly both at the 6-week posttest and 6-month follow-up; however, pain and fatigue decreased significantly at posttest and follow-up for participants with or without arthritis who began the program with moderate or severe pain and fatigue levels. The data from these analyses suggest that, as a component of a workplace wellness program, self-directed Walk With Ease might be effective in increasing physical activity not only among adults with arthritis, but also among persons without arthritis.

Immune-Mediated Protection and Pathogenesis of Chikungunya Virus.

Chikungunya virus (CHIKV) is a re-emerging alphavirus that causes debilitating acute and chronic arthritis. Infection by CHIKV induces a robust immune response that is characterized by production of type I IFNs, recruitment of innate and adaptive immune cells, and development of neutralizing Abs. Despite this response, chronic arthritis can develop in some individuals, which may be due to a failure to eliminate viral RNA and Ag and/or persistent immune responses that cause chronic joint inflammation. In this review, based primarily on advances from recent studies in mice, we discuss the innate and adaptive immune factors that control CHIKV dissemination and clearance or contribute to pathogenesis.

Anti-inflammatory and anti-arthritic effects of methanol extract of the stem bark of Boswellia dalzielii Hutch (Burseraceae) in rats.

Boswellia dalzielii is a tall tree (more than 13 m high) that produces aromatic white flowers. This plant is commonly used in indigenous medicine across Africa against diarrhea, malaria, vomiting, inflammation and arthritis. The present study focuses on the anti-inflammatory and anti-arthritis potential of methanol extract of Boswellia dalzielii (BDME). Anti-inflammatory activity was evaluated in inflammatory models induced by carrageenan, arachidonic acid, histamine, serotonin, prostaglandin and bradykinin. Anti-arthritis activity was measured using complete Freund's adjuvant model. Intracellular and extracellular ROS production and proliferation of T-cells were evaluated using chemiluminescence and liquid scintillation counter techniques, respectively. TNF-α and IL-1ß production were assessed using ELISA and MTT assay performed for cytotoxicity. BDME revealed a significant anti-inflammatory effect by preventing the development of edema caused by carrageenan, arachidonic acid, histamine, serotonin, prostaglandin and bradykinin. For anti-arthritic properties of BDME, the results showed a significant reduction of the joint diameter and a decrease in pain in the treated animals. The extract also showed a noticeable systemic effect, maintaining the values of the evaluated parameters close to normal in treated rats with an inhibition of joint destruction as shown in histopathological analysis. Furthermore, BDME exhibited significant inhibition of extracellular and intracellular ROS production. Still, the extract displayed significant inhibitory activity on T-cell proliferation as well as a reduced production of TNF-α and IL-1ß. Boswellia dalzielii could be considered as a promising tract in the prevention and/or management of inflammatory diseases.

Chronic physical conditions, multimorbidity and physical activity across 46 low- and middle-income countries.

BACKGROUND: There are no nationally representative population-based studies investigating the relationship between physical activity, chronic conditions and multimorbidity (i.e., two or more chronic conditions) in low- and middle-income countries (LMICs), and studies on a multi-national level are lacking. This is an important research gap, given the rapid increase in the prevalence of chronic diseases associated with lifestyle changes in these countries. This cross-sectional study aimed to assess the association between chronic conditions, multimorbidity and low physical activity (PA) among community-dwelling adults in 46 LMICs, and explore the mediators of these relationships. METHODS: World Health Survey data included 228,024 adults aged ≥18 years from 46 LMICs. PA was assessed by the International Physical Activity Questionnaire (IPAQ). Nine chronic physical conditions (chronic back pain, angina, arthritis, asthma, diabetes, hearing problems, tuberculosis, visual impairment and edentulism) were assessed. Multivariable logistic regression and mediation analyses were used to assess the association between chronic conditions or multimorbidity and low PA. RESULTS: Overall, in the multivariable analysis, arthritis (OR = 1.12), asthma (1.19), diabetes (OR = 1.33), edentulism (OR = 1.46), hearing problems (OR = 1.90), tuberculosis (OR = 1.24), visual impairment (OR = 2.29), multimorbidity (OR = 1.31; 95% CI = 1.21-1.42) were significantly associated with low PA. More significant associations were observed in individuals aged ≥50 years. In older adults, depression mediated between 5.1% (visual impairment) to 23.5% (angina) of the association between a chronic condition and low PA. Mobility difficulties explained more than 25% of the association for seven of the eight chronic conditions. Pain was a strong mediator for angina (65.9%) and arthritis (64.9%), while sleep problems mediated up to 43.7% (angina) of the association. CONCLUSIONS: In LMICs, those with chronic conditions and multimorbidity are significantly less physically active (especially older adults). Research on the efficacy and effectiveness of PA in the management of chronic diseases in LMICs is urgently needed. Targeted promotion of physical activity to populations in LMICs experiencing chronic conditions may ameliorate associated depression, mobility difficulties and pain that are themselves important barriers for initiating or adopting an active lifestyle.

Therapeutic effect of IVIG on inflammatory arthritis in mice is dependent on the Fc portion and independent of sialylation or basophils.

High-dose i.v. Ig (IVIG) is used to treat various autoimmune and inflammatory diseases; however, the mechanism of action remains unclear. Based on the K/BxN serum transfer arthritis model in mice, IVIG suppression of inflammation has been attributed to a mechanism involving basophils and the binding of highly sialylated IgG Fc to DC-SIGN-expressing myeloid cells. The requirement for sialylation was examined in the collagen Ab-induced arthritis (CAbIA) and K/BxN serum transfer arthritis models in mice. High-dose IVIG (1-2 g/kg body weight) suppressed inflammatory arthritis when given prophylactically. The same doses were also effective in the CAbIA model when given subsequent to disease induction. In this therapeutic CAbIA model, the anti-inflammatory effect of IVIG was dependent on IgG Fc but not F(ab')2 fragments. Removal of sialic acid residues by neuraminidase had no impact on the anti-inflammatory activity of IVIG or Fc fragments. Treatment of mice with basophil-depleting mAbs did not abrogate the suppression of either CAbIA or K/BxN arthritis by IVIG. Our data confirm the therapeutic benefit of IVIG and IgG Fc in Ab-induced arthritis but fail to support the significance of sialylation and basophil involvement in the mechanism of action of IVIG therapy.

The degree of CD4+ T cell autoreactivity determines cellular pathways underlying inflammatory arthritis.

Although therapies targeting distinct cellular pathways (e.g., anticytokine versus anti-B cell therapy) have been found to be an effective strategy for at least some patients with inflammatory arthritis, the mechanisms that determine which pathways promote arthritis development are poorly understood. We have used a transgenic mouse model to examine how variations in the CD4(+) T cell response to a surrogate self-peptide can affect the cellular pathways that are required for arthritis development. CD4(+) T cells that are highly reactive with the self-peptide induce inflammatory arthritis that affects male and female mice equally. Arthritis develops by a B cell-independent mechanism, although it can be suppressed by an anti-TNF treatment, which prevented the accumulation of effector CD4(+) Th17 cells in the joints of treated mice. By contrast, arthritis develops with a significant female bias in the context of a more weakly autoreactive CD4(+) T cell response, and B cells play a prominent role in disease pathogenesis. In this setting of lower CD4(+) T cell autoreactivity, B cells promote the formation of autoreactive CD4(+) effector T cells (including Th17 cells), and IL-17 is required for arthritis development. These studies show that the degree of CD4(+) T cell reactivity for a self-peptide can play a prominent role in determining whether distinct cellular pathways can be targeted to prevent the development of inflammatory arthritis.

GM-CSF but not IL-17 is critical for the development of severe interstitial lung disease in SKG mice.

Interstitial lung disease (ILD) is a common complication and sometimes a prognostic factor of connective tissue diseases (CTDs) in humans. However, suitable animal model of severe CTD-associated ILD (CTD-ILD) has been limited. In this study, we showed that zymosan-treated SKG mice developed not only arthritis but also chronic-progressive ILD with high mortality over several months. The pathological and clinical features of ILD in zymosan-treated SKG mice were similar to that of human severe CTD-ILD. ILD in this mouse was characterized by massive infiltration of Th17 cells, GM-CSF-producing CD4(+) T cells, and CD11b(+) Gr1(+) neutrophils with fibrosis. Naive SKG T cells were skewed to differentiate into GM-CSF-producing cells, and GM-CSF secreted by T cells enhanced IL-6 and IL-1ß production by macrophages, which in turn enhanced differentiation of IL-17A- and/or GM-CSF-producing T cells and infiltration of neutrophils into lung. Neutralization of GM-CSF completely blocked the development of this ILD, and the blocking of IL-6 signaling resulted in partial prevention of it, whereas neutralization of IL-17A did not. In contrast, the progression of arthritis was inhibited by the neutralization of GM-CSF and slightly by the neutralization of IL-17A, but not by the blocking of IL-6 signaling. These data suggested zymosan-treated SKG mice could be a useful mouse model of severe CTD-ILD, and GM-CSF, rather than IL-17A or IL-6, contributed to the development of ILD in zymosan-treated SKG mice, indicating that neutralization of GM-CSF would be a useful therapeutic strategy for severe CTD-ILD.

Immune responses to Mycoplasma bovis proteins formulated with different adjuvants.

Most vaccines for protection against Mycoplasma bovis disease are made of bacterins, and they offer varying degrees of protection. Our focus is on the development of a subunit-based protective vaccine, and to that end, we have identified 10 novel vaccine candidates. After formulation of these candidates with TriAdj, an experimental tri-component novel vaccine adjuvant developed at VIDO-InterVac, we measured humoral and cell-mediated immune responses in vaccinated animals. In addition, we compared the immune responses after formulation with TriAdj with the responses measured in animals vaccinated with a mix of a commercial adjuvant (Emulsigen™) and 2 of the components of the TriAdj, namely polyinosinic:polycytidylic acid (poly I:C) and the cationic innate defense regulator (IDR) peptide 1002 (VQRWLIVWRIRK). In this latter trial, we detected significant IgG1 humoral immune responses to 8 out of 10 M. bovis proteins, and IgG2 responses to 7 out of 10 proteins. Thus, we concluded that the commercial adjuvant formulated with poly I:C and the IDR peptide 1002 is the best formulation for the experimental vaccine.

A simple pre-operative imaging method to assess donor and recipient anatomy in hemi-hamate arthroplasty for proximal interphalangeal joint reconstruction.

PURPOSE: Post-traumatic arthritis is common in long-term follow-up of patients undergoing hemi-hamate arthroplasty (HHA). We hypothesize that anatomic mismatch could play a role in the development of arthritis. The purpose of this study is to establish a novel, computed tomography (CT)-based imaging technique for pre-operative assessment in HHA. With this technique, our group aims to identify digits with a high likelihood for anatomical mismatch between the donor graft and recipient interphalangeal joint. Using this technique to eliminate cases with high-likelihood of incongruent anatomy, we hypothesize the rates of arthritis could be reduced. METHODS: We conducted a retrospective review of upper extremity CT scans from 2007 to 2014 at our institution. Those studies meeting our inclusion criteria were exported to a clinical radiology software suite. Subsequently, angular and linear measurements of the hamate and potential recipient proximal interphalangeal joints were collected. Angular and linear comparisons were then made between the donor hamate graft and the individual recipient sites. Using pre-established cutoff values, matches were deemed to be inconsistent or consistent. RESULTS: The study included 31 CT scans. The rate of anatomical consistency was low; the small finger was most often consistent (38.7 %) and the index finger was least often consistent (12.9 %). Linear inconsistency was common in all joints besides the small finger; angular inconsistency was most prevalent in the index and long fingers. CONCLUSIONS: This novel use of CT scans as a tool for pre-operative HHA planning is a crucial first step in trying to reduce the observed rates of arthritis after HHA.

[Current therapy of polyarticular forms of juvenile idiopathic arthritis]. / Aktuelle Therapie der polyartikulären Verlaufsform der juvenilen idiopathischen Arthritis.

Juvenile idiopathic arthritis (JIA) is the most common rheumatic disease in infancy and childhood. Approximately 20 % of patients with JIA suffer from the polyarticular form of the disease, which causes a substantial disease burden and long-term sequelae. Therapeutic approaches have used steroids and conventional disease modifying antirheumatic drugs (DMARD) but over the last decade new drugs have become available for the treatment of JIA, in particular biologic DMARD. This article summarizes the current therapy options for polyarticular JIA.

Evaluation of the anti-inflammatory effects of two platelet-rich gel supernatants in an in vitro system of cartilage inflammation.

OBJECTIVES: To study, in normal cartilage explants (CEs) challenged with lipopolysaccharide (LPS), the temporal effects (at 48 and 96h) of leukocyte- and platelet-rich gel (L-PRG) and pure platelet-rich gel (P-PRG) supernatants on the production and degradation of platelet-associated growth factors (GFs) (platelet-derived GF isoform BB [PDGF-BB] and transforming growth factor beta-1 [TGF-ß1]), pro-inflammatory (tumour necrosis factor alpha [TNF-α]) and anti-inflammatory cytokines (interleukin 4 [IL-4] and IL-1 receptor antagonist [IL-1ra]). METHODS: CEs from six horses were challenged with LPS and cultured for 96h with L-PRG and P-PRG supernatants at concentrations of 25% and 50%, respectively. The CE culture medium was changed every 48h and used for determination, by ELISA, of PDGF-BB, TGF-ß1, TNF-α, IL-4 and IL-1ra. RESULTS: Both the 25% and 50% PRG supernatants produced a different molecular profile in the culture media, unlike that of the CE challenged with LPS only. 50% L-PRG produced the most sustained release of growth factors and anti-inflammatory cytokines, although it produced the highest TNF-α release. PDGF-BB was significantly correlated with IL-1ra and TNF-α concentrations, whereas TNF-α was correlated with IL-4. CONCLUSIONS: 50% L-PRG supernatant produced a more sustained concentration of growth factors and anti-inflammatory cytokines than the other hemoderivatives evaluated. This substance could be evaluated in animal models of arthritis or in patients with arthropathies.

Various regimens for prophylactic treatment of patients with haemophilia.

Haemophilia prophylaxis is superior to on-demand treatment to prevent joint damage. 'High-dose prophylaxis' as used in Sweden is more effective in preventing arthropathy than an 'intermediate-dose regimen' (the Netherlands) and the Canadian tailored primary prophylaxis. Prophylaxis may reduce the risk of developing inhibitors. There is no difference in inhibitor risk between plasma derived and recombinant factor VIII (rFVIII) products but the Rodin study showed increased risk with second-generation rFVIII products. MRI is a new and very sensitive tool to detect the symptoms of early arthropathy but some results (soft tissue changes in 'bleed-free joints') still need to be investigated. Ultrasound is a very helpful method to aid diagnosis especially during the acute phase of a bleed. The risk of infection with central venous access remains a matter of debate. A fully implanted central venous access device (CVAD) has a significant lower risk of infection compared to external CVADs. Patient's age under 6 yr and inhibitor presence are additional risk factors for infections. The role of arteriovenous fistulae needs to be investigated because significant complications have been reported. Disease-specific quality of life instruments are complementary to generic instruments evaluating QoL in patients with haemophilia and have become important health outcome measures.

Engineered regulatory T cells coexpressing MHC class II:peptide complexes are efficient inhibitors of autoimmune T cell function and prevent the development of autoimmune arthritis.

Regulatory T cells (Tregs) are critical homeostatic components in preventing the development of autoimmunity, and are a major focus for their therapeutic potential for autoimmune diseases. To enhance the efficacy of Tregs in adoptive therapy, we developed a strategy for generating engineered Tregs that have the capacity to target autoimmune T cells in an Ag-specific manner. Using a retroviral expression system encoding Foxp3 and HLA-DR1 covalently linked to the immunodominant peptide of the autoantigen type II collagen (DR1-CII), naive T cells were engineered to become Tregs that express DR1-CII complexes on their surface. When these cells were tested for their ability to prevent the development of collagen induced arthritis, both the engineered DR1-CII-Foxp3 and Foxp3 only Tregs significantly reduced the severity and incidence of disease. However, the mechanism by which these two populations of Tregs inhibited disease differed significantly. Disease inhibition by the DR1-CII-Foxp3 Tregs was accompanied by significantly lower numbers of autoimmune CII-specific T cells in vivo and lower levels of autoantibodies in comparison with engineered Tregs expressing Foxp3 alone. In addition, the numbers of IFN-γ- and IL-17-expressing T cells in mice treated with DR1-CII-Foxp3 Tregs were also significantly reduced in comparison with mice treated with Foxp3 engineered Tregs or vector control cells. These data indicate that the coexpression of class II autoantigen-peptide complexes on Tregs provides these cells with a distinct capacity to regulate autoimmune T cell responses that differs from that used by conventional Tregs.

[Differential diagnosis of sternoclavicular arthritis]. / Differenzialdiagnose der Sternoclaviculararthritis.

A 47-year-old male patient presented with a 6-month history of a painful swelling in the region of the right sternoclavicular joint together with fatigue. Initial investigations including X-rays of the sternoclavicular joint did not reveal any pathological conditions. Eventually, a CT scan revealed marked joint destruction, pulmonary condensation, and enlargement of the adrenal glands. Subsequent procedures, such as joint fluid aspiration and bronchoalveolar lavage, proved to be positive for Mycobacterium tuberculosis. After initiation of a standard combination therapy (four tuberculostatic drugs) the general condition of the patient stabilized and he was discharged from hospital after 4 weeks.

Ly6G ligation blocks recruitment of neutrophils via a ß2-integrin-dependent mechanism.

Ly6G is a glycosylphosphatidylinositol (GPI)-anchored protein of unknown function that is commonly targeted to induce experimental neutrophil depletion in mice. In the present study, we found that doses of anti-Ly6G Abs too low to produce sustained neutropenia remained capable of inhibiting experimental arthritis, leaving joint tissues free of infiltrating neutrophils. Thioglycollate-stimulated peritonitis was also attenuated. No alteration in neutrophil apoptosis was observed, implicating impaired recruitment. Indeed, Ly6G ligation abrogated neutrophil migration toward LTB(4) and other chemoattractants in a transwell system. Exploring the basis for this blockade, we identified colocalization of Ly6G and ß2-integrins by confocal microscopy and confirmed close association by both coimmunoprecipitation and fluorescence lifetime imaging microscopy. Anti-Ly6G Ab impaired surface expression of ß2-integrins in LTB(4)-stimulated neutrophils and mimicked CD11a blockade in inhibiting both ICAM-1 binding and firm adhesion to activated endothelium under flow conditions. Correspondingly, migration of ß2-integrin-deficient neutrophils was no longer inhibited by anti-Ly6G. These results demonstrate that experimental targeting of Ly6G has functional effects on the neutrophil population and identify a previously unappreciated role for Ly6G as a modulator of neutrophil migration to sites of inflammation via a ß2-integrin-dependent mechanism.

Physical activity and health outcomes: evidence from Canada.

Health production models include participation in physical activity as an input. We investigate the relationship between participation in physical activity and health using a bivariate probit model. Participation is identified with an exclusion restriction on a variable reflecting sense of belonging to the community. Estimates based on data from Cycle 3.1 of the Canadian Community Health Survey indicate that participation in physical activity reduces the reported incidence of diabetes, high blood pressure, heart disease, asthma, and arthritis as well as being in fair or poor health. Increasing the intensity above the moderate level and frequency of participation in physical activity appears to have a diminishing marginal impact on adverse health outcomes. Our results provide support for guidelines about engaging in exercise regularly to achieve health benefits.