C3d-Targeted factor H inhibits tissue complement in disease models and reduces glomerular injury without affecting circulating complement

Complement-mediated diseases can be treated using systemic inhibitors. However, complement components are abundant in circulation, affecting systemic inhibitors' exposure and efficacy. Furthermore, because of complement's essential role in immunity, systemic treatments raise infection risk in patients. To address these challenges, we developed antibody fusion proteins combining the alternative-pathway complement inhibitor factor H (fH1-5) with an anti-C3d monoclonal antibody (C3d-mAb-2fH). Because C3d is deposited at sites of complement activity, this molecule localizes to tissue complement while minimizing circulating complement engagement. These fusion proteins bind to deposited complement in diseased human skin sections and localize to activated complement in a primate skin injury model. We further explored the pharmacology of C3d-mAb-2fH proteins in rodent models with robust tissue complement activation. Doses of C3d-mAb-2fH >1 mg/kg achieved >75% tissue complement inhibition in mouse and rat injury models while avoiding circulating complement blockade. Glomerular-specific complement inhibition reduced proteinuria and preserved podocyte foot-process architecture in rat membranous nephropathy, indicating disease-modifying efficacy. These data indicate that targeting local tissue complement results in durable and efficacious complement blockade in skin and kidney while avoiding systemic inhibition, suggesting broad applicability of this approach in treating a range of complement-mediated diseases.

Proportion and Correlates of Children in the US-Affiliated Pacific Region Meeting Sleep, Screen Time, and Physical Activity Guidelines

INTRODUCTION

Limited data on 24-hour movement behaviors of children aged 5-8 years exist globally. We describe the prevalence and sociodemographic associations of meeting physical activity (PA), sedentary recreational screen time (ST), and sleep guidelines among children from 11 jurisdictions in the US-Affiliated Pacific region.

METHODS

Cross-sectional representative data from 1192 children aged 5-8 years living in the US-Affiliated Pacific region were drawn from the baseline 2012-2014 Children's Healthy Living Program. Sleep and moderate- to vigorous-intensity PA were calculated from accelerometry. ST and sociodemographic data were collected from caregiver surveys. The percentage of children meeting the Asia-Pacific 24-hour movement guidelines for PA (≥60 min/d of moderate- to vigorous-intensity PA), sleep (≥9 and ≤ 11 h/d) and ST (≤2 h/d) were calculated. Generalized linear mixed models were used to examine associations with adiposity and sociodemographic variables.

RESULTS

Twenty-seven percent (95% confidence interval, 24.6-30.0) of children met integrated guidelines; 98% (96.2-98.0) met PA, 78% (75.4-80.0) met sleep, and 35% (32.6-38.0) met ST guidelines. Females (adjusted odds ratio = 1.40 [95% confidence interval, 1.03-1.91]) and those living in lower-middle-income jurisdictions (2.29 [1.49-3.54]) were more likely to meet ST guidelines. Overweight children (0.62 [0.40-0.96]), those aged 8 years (0.39 [0.22-0.69]), and children with caregivers of an education level of high school or beyond (0.44 [0.29-0.68]) were less likely to achieve ST guidelines. Children from midrange annual household incomes were less likely to meet combined guidelines (0.60 [0.39-0.92]).

CONCLUSIONS

Three-quarters of children are not meeting integrated Asia-Pacific 24-hour movement guidelines. Future strategies for reducing ST and increasing integrated guidelines compliance are needed.

Children's physical activity and sedentary behaviour in before school care: An observational study

OBJECTIVE

In Australia, less than one quarter of children aged 5-12 years meet national physical activity (PA) guidelines. Before school care operates as part of Out of School Hours Care (OSHC) services and provide opportunities for children to meet their daily PA recommendations. The aim of this study was to explore factors associated with children meeting 15 min of moderate-to-vigorous-intensity physical activity (MVPA) while attending before school care.

METHODS

A cross-sectional study was conducted in 25 services in New South Wales, Australia. Each service was visited twice between March and June 2021. Staff behaviours and PA type and context were captured using staff interviews and the validated System for Observing Staff Promotion of Physical Activity and Nutrition (SOSPAN) time sampling tool. Child PA data were collected using Actigraph accelerometers and associations between program practices and child MVPA analysed.

RESULTS

PA data were analysed for 654 children who spent an average of 39.2% (±17.6) of their time sedentary; 45.4% (±11.4) in light PA; and 14.9% (±11.7) in MVPA. Only 17% of children (n = 112) reached ≥15 min MVPA, with boys more likely to achieve this. Children were more likely to meet this recommendation in services where staff promoted and engaged in PA; PA equipment was available; children were observed in child-led free play; and a written PA policy existed.

CONCLUSIONS

Before school care should be supported to improve physical activity promotion practices by offering staff professional development and guidance on PA policy development and implementation practices.

Correlates of physical activity and sedentary behaviour in children attending before and after school care: a systematic review

BACKGROUND

Out of School Hours Care (OSHC) offers structured care to elementary/primary-aged children before and after school, and during school holidays. The promotion of physical activity in OSHC is important for childhood obesity prevention. The aim of this systematic review was to identify correlates of objectively measured physical activity and sedentary behaviour in before and after school care.

METHODS

A systematic search was conducted in Scopus, ERIC, MEDLINE (EBSCO), PsycINFO and Web of Science databases up to December 2021. Study inclusion criteria were: written in English; from a peer-reviewed journal; data from a centre-based before and/or after school care service; children with a mean age < 13 years; an objective measure of physical activity or sedentary behaviour; reported correlations and significance levels; and if an intervention study design these correlates were reported at baseline. Study quality was assessed using the Office of Health Assessment and Translation Risk of Bias Rating Tool for Human and Animal Studies. The PRISMA guidelines informed the reporting, and data were synthesised according to shared correlations and a social ecological framework.

RESULTS

Database searches identified 4559 papers, with 18 cross-sectional studies meeting the inclusion criteria.There were a total of 116 physical activity correlates and 64 sedentary behaviour correlates identified. The most frequently reported correlates of physical activity were child sex (males more active), staff engaging in physical activity, an absence of elimination games, and scheduling physical activity in daily programming (all more positively associated). The most frequently reported correlates of sedentary behaviour were child sex (females more sedentary) and age (older children more sedentary).

CONCLUSIONS

Encouraging physical activity engagement of female children, promoting positive staff behaviours, removing elimination elements from games, and scheduling more time for physical activity should be priorities for service providers. Additional research is needed in before school care services.

Correlates of children's dietary intake, physical activity and sedentary behavior in home-based childcare: A systematic review

This systematic review assessed the correlates of children's dietary intake, physical activity and sedentary behavior in home-based childcare. A systematic search of five databases with articles published between January 2000 and July 2021 was conducted. Articles were included if they contained data from a home-based childcare (birth-5 years) setting; were a quantitative study that reported children's dietary intake, physical activity or sedentary behavior; included variables associated with children's dietary intake, physical activity or sedentary behavior; and were published in English. Correlates were categorized using McLeroy’s social ecological framework. Risk of bias was assessed using the Office of Health Assessment and Translation (OHAT) Risk of Bias Rating Tool. Fifteen studies met the inclusion criteria; six assessed children's dietary intake, and nine assessed physical activity and/or sedentary behaviors. Studies were conducted in the USA (n = 12) and Canada (n = 3). Seventy-three correlates were identified, for children's dietary intake (n = 11), physical activity (n = 35) and sedentary behavior (n = 27). Ethnicity and the food provided to children were associated with children's dietary intake in two studies; both from the same study sample. Indoor play space was positively associated with physical activity in two separate studies. No consistent associations for children's dietary intake, physical activity, or sedentary behavior outcomes were found between studies, however few studies assessed the same correlates. High-quality studies conducted in different countries that assess the nutrition and physical activity environments in home-based childcare using reliable and consistent methods are needed. This review was registered with PROSPERO, no. CRD42019103429.

Development and Optimization of Bifunctional Fusion Proteins to Locally Modulate Complement Activation in Diseased Tissue

Sustained complement activation is an underlying pathologic driver in many inflammatory and autoimmune diseases. Currently approved anti-complement therapies are directed at the systemic blockade of complement. Consequently, these therapies provide widespread inhibition of complement pathway activity, beyond the site of ongoing activation and the intended pharmacodynamic (PD) effects. Given the essential role for complement in both innate and adaptive immunity, there is a need for therapies that inhibit complement in diseased tissue while limiting systemic blockade. One potential approach focuses on the development of novel fusion proteins that enable tissue-targeted delivery of complement negative regulatory proteins. These therapies are expected to provide increased potency and prolonged tissue PD, decreased dosing frequency, and the potential for improved safety profiles. We created a library of bifunctional fusion proteins that direct a fragment of the complement negative regulator, complement receptor type 1 (CR1) to sites of tissue injury. Tissue targeting is accomplished through the binding of the fusion protein to complement C3 fragments that contain a surface-exposed C3d domain and which are covalently deposited on tissues where complement is being activated. To that end, we generated a fusion protein that contains an anti-C3d monoclonal antibody recombinantly linked to the first 10 consensus repeats of CR1 (CR11-10) with the intention of delivering high local concentrations of this complement negative regulatory domain to tissue-bound complement C3 fragments iC3b, C3dg and C3d. Biochemical and in vitro characterization identified several fusion proteins that inhibit complement while maintaining the C3d domain binding properties of the parent monoclonal antibody. Preclinical in vivo studies further demonstrate that anti-C3d fusion proteins effectively distribute to injured tissue and reduce C3 fragment deposition for periods beyond 14 days. The in vitro and in vivo profiles support the further evaluation of C3d mAb-CR11-10 as a novel approach to restore proper complement activation in diseased tissue in the absence of continuous systemic complement blockade.

Foods and beverages provided in out of school hours care services: an observational study

Introduction

Out of school hours care (OSHC) is a fast-growing childcare setting in Australia, however the types of foods and beverages offered are relatively unknown. This study describes the food and beverages offered and investigates sector-level and setting-level factors which may impact OSHC in meeting the Australian Dietary Guidelines (ADG).

Methods

This cross-sectional, observational study was conducted in 89 OSHC services (between 2018 and 2019). Food and beverages offered, kitchen facilities and menus were captured via direct observation. Foods were categorised into five food groups or discretionary foods, based on the ADG, and frequencies determined. Short interviews with OSHC directors ascertained healthy eating policies, staff training, food quality assessment methods and food budgets. Fisher’s exact test explored the influence of sector-level and setting-level factors on food provision behaviours.

Results

Discretionary foods (1.5 ± 0.68) were offered more frequently than vegetables (0.82 ± 0.80) (p < .001), dairy (0.97 ± 0.81) (p = .013) and lean meats (0.22 ± 0.54) (p < .001). OSHC associated with long day care and reported using valid food quality assessment methods offered more lean meats (p= .002, and p= .004). Larger organisations offered more vegetables (p = .015) and discretionary foods (p= .007). Menus with clearly worded instructions to provide fruits and vegetables daily offered more fruit (p= .009), vegetables (p < .001) and whole grains (p= .003). No other sector or setting-level factors were associated with services aligning with the ADG.

Conclusion

Future interventions could benefit from trialling menu planning training and tools to assist OSHC services in NSW meet the ADG requirements.

Physical activity in out of school hours care: an observational study

Background

Opportunities for physical activity within out of school hours care (OSHC) are not well documented in Australia. This study explored factors associated with children (5–12 years) meeting 30 min of moderate to vigorous physical activity (MVPA) while attending OSHC in the afternoon period.

Methods

A cross-sectional study, conducted in 89 OSHC services in New South Wales, Australia, serving 4,408 children. Each service was visited twice between 2018–2019. Physical activity promotion practices were captured via short interviews and System for Observing Staff Promotion of Physical Activity and Nutrition (SOSPAN). Physical activity spaces was measured (m²) and physical activity of 3,614 child days (42% girls), were collected using Acti-Graph accelerometers. Association between program practices and children accumulation of MVPA was tested using mixed effects logistic regression, adjusted by OSHC service and child.

Results

Twenty-six percent of children (n = 925) accumulated 30 min or more of MVPA. Factors associated with children reaching MVPA recommendations included: services scheduling greater amounts of child-led free play, both 30–59 min (OR 2.6, 95%CI 1.70, 3.98) and ≥ 60 min (OR 6.4, 95%CI 3.90, 10.49); opportunities for staff-led organised play of ≥ 30 min (OR 2.3, 95%CI 1.47, 3.83); and active games that engaged the majority of children (OR 1.7, 95%CI 1.11, 2.61). Children were less likely to meet MVPA recommendations if services played games with elimination components (OR 0.56, 95%CI 0.37, 0.86).

Conclusion

Improvements to service-level physical activity promotion practices, specifically the type of physical activity scheduled and the structure of games, may be an effective strategy to increase MVPA of children attending OSHC afterschool in NSW, Australia.

Monocytes may promote myofibroblast accumulation and apoptosis in Alport renal fibrosis

BACKGROUND

In interstitial fibrosis, monocytes and myofibroblasts have been directly implicated in scarring, apoptosis, and tissue necrosis. While much has been done to explore the role of these cell types individually in fibrosis, the interactive dependency of monocytes and myofibroblasts has been only marginally explored.

METHODS

Alport mice were treated or not with a soluble receptor inhibitor for transforming growth factor-beta 1 (TGF-beta 1), which was previously shown to inhibit the accumulation of myofibroblasts, but not monocytes, in the tubulointerstitium. Kidneys were examined for fibrosis using several matrix markers, TGF-beta 1 mRNA expression by in situ hybridization, apoptosis using the terminal deoxynucleotidyl transferase-mediated uridine triphosphate nick end labeling (TUNEL) assay, expression of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPS) by dual immunofluorescence microscopy, MMP activity by gelatin and in situ zymography, MMP mRNA expression by reverse transcription-polymerase chain reaction (RT-PCR), and basement membrane degradation by dual immunofluorescence confocal microscopy and electron microscopy.

RESULTS

Treated mice showed a markedly reduced accumulation of matrix proteins. Tissue monocytes express TGF-beta 1 mRNA, and TGF-beta 1 is required for myofibroblast accumulation. The number of apoptotic cells was not influenced by TGF-beta 1 inhibition. Monocytes express MMP-2, MMP-9, TIMP-2, and TIMP-3. MMP activity and mRNA expression is equally up regulated in treated and untreated Alport mice. Tubular basement membranes (TBM) around clusters of monocytes are notably degraded. TGF-beta 1 inhibition does not extend the life of Alport mice.

CONCLUSION

These studies demonstrate that monocytes may influence myofibroblast accumulation via TGF-beta1, and that monocytes, and not myofibroblasts, are associated with tubular atrophy in Alport mice. Elevated MMP expression and activity is associated with TBM destruction near monocytes clusters, suggesting an anoikis mechanism may contribute to apoptosis in this model.

Transforming growth factor-beta-dependent events in vascular remodeling following arterial injury

Constrictive remodeling has been identified as a major contributor to restenosis following angioplasty. Characterization of transforming growth factor-beta (TGF-beta)-mediated cellular events in the adventitia and their contribution to vascular remodeling, however, has not previously been studied in detail. The balloon catheter denudation model was performed on rat carotid artery, and groups of rats were treated with vehicle or a TGF-beta inhibitor, a soluble TGF-beta receptor type II (TGF-beta R:Fc). Adventitial cell proliferation, which peaked 4 days after injury, was characterized by the de novo formation of several cell layers surrounding the outer adventitia and this process was not dependent upon TGF-beta activity. These neoadventitial cells expressed an abundance of collagen type I and a fetal isoform of fibronectin containing the EIIIA domain, and the expression of both proteins was suppressed in the presence of TGF-beta R:Fc. Lumenal narrowing was apparent 14 days after injury. Inhibition of TGF-beta signaling promoted vessel enlargement. As a result, lumen size did not change despite neointima formation. In conclusion, adventitial fibrosis with abundant collagen matrix deposition but not adventitial cell proliferation is dependent upon endogenous TGF-beta activity. Furthermore, inhibition of TGF-beta signaling prevents injury-induced reduction in lumen area by promoting vessel enlargement.

Global gene expression analysis reveals a role for the alpha 1 integrin in renal pathogenesis

Kidney fibrosis is the hallmark of most types of progressive kidney disease, including the genetic disorder Alport's syndrome. We undertook gene expression analysis in Alport's syndrome mouse kidneys using microchip arrays to characterize the development of fibrosis. In addition to matrix and matrix-remodeling genes, consistent with interstitial fibrosis, macrophage-related genes show elevated expression levels in Alport's syndrome kidneys. Immunohistochemical analysis of kidney sections illustrated that macrophages as well as myofibroblasts accumulate in the tubular interstitium. Deletion of alpha(1) integrin results in decreased accumulation of both myofibroblasts and macrophages in the tubular interstitium in Alport's syndrome mice and delays disease progression. Transforming growth factor beta antagonism, although reducing interstitial fibrosis, does not limit macrophage accumulation in the tubular interstitium and disease progression. In this study, we identified previously overlooked inflammatory events that occur in the tubulointerstitial region. We propose that in addition to the previously suggested role for the alpha(1)beta(1) integrin in mesangial expansion and abnormal laminin deposition, this integrin may be critical for monocyte accumulation that, in turn, may lead directly to renal failure. Our gene expression and immunohistochemical data indicate that macrophage accumulation is dependent on alpha(1) integrin expression on the macrophage cell surface and that anti-alpha(1) integrin strategies may be employed as therapeutics in the treatment of chronic inflammatory and fibrotic diseases.

Effect of antibody against integrin alpha4 on bleomycin-induced pulmonary fibrosis in mice

Integrins are a family of transmembrane glycoproteins that can interact with components of the extracellular matrix. The alpha4beta1 and alpha4beta7 integrins are heterodimeric leukocyte cell surface molecules critical to their cell and matrix adhesive interactions. Evidence for a central role for the alpha4 integrins in leukocyte pathophysiology in the lung is well documented. In this study, we tested the hypothesis that neutralizing antibody for integrin alpha4 (PS2) may reduce bleomycin (BL)-induced lung fibrosis in vivo. Male C57BL/6 mice were injected intratracheally with saline (SA) or BL (0.08 U/mouse) followed by intraperitoneal injection of SA, isotype control antibody (1E6), or PS2 (100 microg) three times a week. Twenty-one days after the intratracheal instillation, mice were killed for bronchoalveolar lavage (BAL), biochemical, histopathological, and immunohistological analyses. Treatment with PS2 significantly reduced BL-induced increases in lung lipid peroxidation and hydroxyproline content. Lung histopathology also showed reduced fibrotic lesions in the BL-treated lungs by treatment with PS2. BL-treated mouse lungs also showed induction of cells with the myofibroblast phenotype, as indicated by the increased expression of alpha-smooth muscle actin (alphaSMA), whereas treatment with PS2 minimized the BL-induced alphaSMA expression. Furthermore, treatment with PS2 reduced the BL-induced increase in the BAL total cell number, and attenuated the BL-induced increase in the BAL protein level. It is concluded that integrin alpha4 may play an important role in BL-induced pulmonary fibrosis, and the use of anti-alpha4 antibody offers therapeutic antifibrotic potential in vivo.

Reduction of bleomycin induced lung fibrosis by transforming growth factor beta soluble receptor in hamsters

BACKGROUND

Transforming growth factor beta (TGF-beta) is a key mediator of collagen synthesis in the development of lung fibrosis. It has previously been shown that the administration of TGF-beta antibody and TGF-beta binding proteoglycan, decorin, reduced bleomycin (BL) induced lung fibrosis in animals. The present study was carried out to investigate whether intratracheal instillation of TGF-beta soluble receptor (TR) would minimise the BL induced lung fibrosis in hamsters.

METHODS

The effect of a recombinant TR (TGFbetaRII) on the lung collagen accumulation was evaluated in a BL hamster model of pulmonary fibrosis. Animals were divided into four groups and intratracheally injected with saline or BL at 6.5 U/4 ml/kg followed by intratracheal instillation of phosphate buffered saline (PBS) or 4 nmol TR in 0.3 ml twice a week. Twenty days after the first intratracheal instillation the hamsters were killed for bronchoalveolar lavage (BAL) fluid, biochemical, and histopathological analyses.

RESULTS

Treatment of hamsters with TR after intratracheal instillation of BL significantly reduced BL induced lung fibrosis as shown by decreases in the lung hydroxyproline level and prolyl hydroxylase activity, although they were still significantly higher than those of the saline control. Histopathological examination showed a considerable decrease in BL induced fibrotic lesions by TR treatment. However, TR did not prevent the BL induced increases in total cells and protein in the BAL fluid.

CONCLUSIONS

These results suggest that TR has antifibrotic potential in vivo and may be useful in the treatment of fibrotic diseases where increased TGF-beta is associated with excess collagen accumulation.

Divalent cations stabilize the alpha 1 beta 1 integrin I domain

Recent structural and functional analyses of alpha integrin subunit I domains implicate a region in cation and ligand binding referred to as the metal ion-dependent adhesion site (MIDAS). Although the molecular interactions between Mn2+ and Mg2+ and the MIDAS region have been defined by crystallographic analyses, the role of cation in I domain function is not well understood. Recombinant alpha 1 beta 1 integrin I domain (alpha1-I domain) binds collagen in a cation-dependent manner. We have generated and characterized a panel of antibodies directed against the alpha1-I domain, and selected one (AJH10) that blocks alpha 1 beta 1 integrin function for further study. The epitope of AJH10 was localized within the loop between the alpha 3 and alpha 4 helices which contributes one of the metal coordination sites of the MIDAS structure. Kinetic analyses of antibody binding to the I domain demonstrate that divalent cation is required to stabilize the epitope. Denaturation experiments demonstrate that cation has a dramatic effect on the stabilization of the I domain structure. Mn2+ shifts the point at which the I domain denatures from 3.4 to 6.3 M urea in the presence of the denaturant, and from 49.5 to 58.6 degrees C following thermal denaturation. The structural stability provided to the alpha1-I domain by divalent cations may contribute to augmented ligand binding that occurs in the presence of these cations.

Induced fit activation mechanism of the exceptionally specific serine protease, complement factor D

We have investigated the mechanism by which the complement protease, Factor D, achieves its high specificity for the cleavage of Factor B in complex with C3(H2O). Kinetic experiments showed that Factor B and C3(H2O) associate with a KD of >/=2.5 microM and that Factor D acts on this complex with a second-order rate constant of kcat/KM >/= 2 x 10(6) M-1 s-1, close to the rate of a diffusion-controlled reaction for proteins of this size. In contrast, Factor D, which is a member of the trypsin family of serine proteases, was 10(3)-10(4)-fold less active than trypsin toward both thioester and p-nitroanilide substrates containing an arginine at P1. Furthermore, peptides spanning the Factor B cleavage site were not detectably cleaved by Factor D (kcat/KM </= 0.5 M-1 s-1). These results imply that contacts between Factor D and the C3(H2O)B complex, outside the vicinity of the cleavage site in Factor B, generate >/=9 kcal/mol of binding energy to stabilize the transition state for reaction. In support of this, we demonstrate that chemical modification of Factor D at a single lysine residue that is distant from the active site abolishes the activity of the enzyme toward Factor B while not affecting activity toward small synthetic substrates. We propose that Factor D may exemplify a special case of the induced fit mechanism in which the requirement for conformational activation of the enzyme results in a substantial increase in substrate specificity.

Epitope mapping of a function-blocking beta 1 integrin antibody by phage display

Integrins are a major class of cell surface receptors involved in cell-cell and cell-matrix adhesion and communication. Ha2/11 is a function-blocking anti-rat beta 1 integrin hamster IgM that should be a useful reagent for understanding beta 1 integrin function. We demonstrate that Ha2/11 cross reacts with human, Xenopus, and Drosophila beta 1 integrins, and use phage display to map the epitope for Ha2/11 to residues within the sequence LRSGEPQTF which lies 18 amino acids proximal to the putative I domain in beta 1 integrins. Monoclonal antibody mapping experiments, mutational analyses, and direct binding assays have implicated integrin I domains in both cation and ligand binding. Our data therefore suggest that Ha2/11 blocks beta 1 integrin function by interfering with I domain-mediated ligand binding.