HIF activation enhances FcγRIIb expression on mononuclear phagocytes impeding tumor targeting antibody immunotherapy

BACKGROUND

Hypoxia is a hallmark of the tumor microenvironment (TME) and in addition to altering metabolism in cancer cells, it transforms tumor-associated stromal cells. Within the tumor stromal cell compartment, tumor-associated macrophages (TAMs) provide potent pro-tumoral support. However, TAMs can also be harnessed to destroy tumor cells by monoclonal antibody (mAb) immunotherapy, through antibody dependent cellular phagocytosis (ADCP). This is mediated via antibody-binding activating Fc gamma receptors (FcγR) and impaired by the single inhibitory FcγR, FcγRIIb.

METHODS

We applied a multi-OMIC approach coupled with in vitro functional assays and murine tumor models to assess the effects of hypoxia inducible factor (HIF) activation on mAb mediated depletion of human and murine cancer cells. For mechanistic assessments, siRNA-mediated gene silencing, Western blotting and chromatin immune precipitation were utilized to assess the impact of identified regulators on FCGR2B gene transcription.

RESULTS

We report that TAMs are FcγRIIbbright relative to healthy tissue counterparts and under hypoxic conditions, mononuclear phagocytes markedly upregulate FcγRIIb. This enhanced FcγRIIb expression is transcriptionally driven through HIFs and Activator protein 1 (AP-1). Importantly, this phenotype reduces the ability of macrophages to eliminate anti-CD20 monoclonal antibody (mAb) opsonized human chronic lymphocytic leukemia cells in vitro and EL4 lymphoma cells in vivo in human FcγRIIb+/+ transgenic mice. Furthermore, post-HIF activation, mAb mediated blockade of FcγRIIb can partially restore phagocytic function in human monocytes.

CONCLUSION

Our findings provide a detailed molecular and cellular basis for hypoxia driven resistance to antitumor mAb immunotherapy, unveiling a hitherto unexplored aspect of the TME. These findings provide a mechanistic rationale for the modulation of FcγRIIb expression or its blockade as a promising strategy to enhance approved and novel mAb immunotherapies.

Metabolic profile of female lambs on annual ryegrass pasture managed under different grazing intensities and methods

ABSTRACT The aim of this study was to evaluate the effect of grazing methods and intensities on the metabolic profile of lambs grazing ryegrass. This study was performed in Eldorado do Sul (RS). The treatments consisted of two grazing intensities with rotational and continuous stocking methods: moderate and low. The experimental design was a randomized block arranged in a factorial scheme with four replicates. To evaluate the metabolic and nutritional conditions of the lambs, blood samples were collected to evaluate phosphorus, albumin, glucose, magnesium, globulin, cortisol, urea and total proteins. The highest blood urea value was observed in the month of September in lambs kept in continuous method grazing. There was no statistical difference between the grazing intensities and grazing methods for albumin, glucose, magnesium, globulin, cortisol and total protein levels in profile lambs. The cortisol values suggested that the animals were not subjected to high stress levels. In conclusion, rearing female lambs on ryegrass, irrespective of grazing methods or intensities, allowed the maintenance of body homeostasis and did not cause any metabolic unbalances, nutritional unbalances or stress.

Short-chain fatty acids and FFAR2 as suppressors of bone resorption

Short-chain fatty acids (SCFAs) exert a variety of immune and metabolic functions by binding to G-protein-coupled receptors, mainly free fatty acid receptor 2 (FFAR2). However, the effects of SCFAs and FFARs on bone remodeling, especially in alveolar bone, have been less explored. In this study, we investigated the influence of the SCFA/FFAR2 axis on alveolar bone. Bone samples from wild-type (WT) and FFAR2-deficient mice (FFAR2-/-) were analyzed using micro-CT, histology and qPCR. WT and FFAR2-/- animals received a high-fiber diet (HFD) reported to increase circulating levels of SCFAs. Additionally, we analyzed the effects of SCFAs and a synthetic FFAR2 agonist, phenylacetamide-1 (CTMB), on bone cell differentiation. The participation of histone deacetylase inhibitors (iHDACs) in the effects of SCFAs was further assessed in vitro. CTMB treatment was also evaluated in vivo during orthodontic tooth movement (OTM). FFAR2-/- mice exhibited deterioration of maxillary bone parameters. Consistent with this, FFAR2-/- mice exhibited a significant increase of OTM and changes in bone cell numbers and in the expression of remodeling markers. The HFD partially reversed bone loss in the maxillae of FFAR2-/- mice. In WT mice, the HFD induced changes in the bone markers apparently favoring a bone formation scenario. In vitro, bone marrow cells from FFAR2-/- mice exhibited increased differentiation into osteoclasts, while no changes in osteoblasts were observed. In line with this, differentiation of osteoclasts was diminished by SCFAs and CTMB. Moreover, CTMB treatment significantly reduced OTM. Pretreatment of osteoclasts with iHDACs did not modify the effects of SCFAs on these cells. In conclusion, SCFAs function as regulators of bone resorption. The effects of SCFAs on osteoclasts are dependent on FFAR2 activation and are independent of the inhibition of HDACs. FFAR2 agonists may be useful to control bone osteolysis.

Influence of interdigitation and expander type in the mechanical response of the midpalatal suture during maxillary expansion

BACKGROUND AND OBJECTIVE

The orthopedic Maxillary Expansion (ME) procedure is used for treating the transverse maxillary deficiency. This pathology consists in a smaller transverse dimension in the maxilla and leads to malocclusion. The treatment takes advantage of the existence of the midpalatal suture (MPS), which corresponds to the junction at the palatine bones of its horizontal portions. The technique employs a device, conventionally a palatal expander attached to the posterior teeth, to separate the two maxillary bones in the MPS. The objective of this study was to analyze, using the Finite Element Method, the biomechanical behavior of the MPS when an expansion is applied.

METHODS

A Computer Tomography image of the maxilla was reconstructed, the suture geometry was modeled with different interdigitation levels and types of hyrax devices. A total of 12 geometric models (three levels for interdigitation and four types of hyrax devices) were prepared and analyzed taking into account the chewing forces and the expansion displacement. For each case, maximum principal stresses on the maxilla (bone), and equivalent stresses on the expander device (stainless steel) were observed. In the MPS, maximum principal stresses and directional displacement were evaluated.

RESULTS

The results showed that the interdigitation does not have an important influence on the deformation behavior of the maxilla but it affects the stress distribution. In addition, the type of expander device and anchorage have a direct relationship with the treatment effectiveness; larger deformation in the expansion direction was obtained with skeletal when compared to dental anchorage.

CONCLUSIONS

A study that allows a better understanding of the oral biomechanics during the application of ME was presented. To our knowledge, it is the first study based on computational simulations that takes into account bone structures, like maxilla and part of the skull, to analyze the interdigitation influence on the MPS behavior when exposed to a ME.

Grazing criteria for perennial peanut (Arachis pintoi cv. Amarillo) consumed by sheep in rotational stocking

ABSTRACT The objective of work was to study the productive profile of perennial peanut in a rotational stocking environment under different criteria. The treatments corresponded to pre-grazing height of 14 and 18cm or 95% of light interception (LI) distributed in a completely randomized design. The studied variables were forage mass, percentage of structural components, forage mass and the structural components in the lower and upper canopy strata. The entrance criterion of 18cm in height, despite having higher forage mass, presented lower percentage of leaves and higher percentage of stems and forage losses. The criteria of 14cm and 95% light interception presented similar production between them and the highest rate of forage accumulation. In all criteria, in the upper strata of pasture a higher percentage of leaves were found. The criteria of 95% LI and 14cm in height presented the best productive performances. The entry criterion of 18cm presented a higher mass of pre-grazing forage with lower percentage of dead material, but with higher forage losses, resulting from senescent leaves. Due to changes in the structural components, as grazing cycles increase, the interception of 95% of the incident light by the perennial peanut occurs at lower heights.

Osteoprotective Effects of Estrogen in the Maxillary Bone Depend on ERα

Estrogen deficiency results in disruption of maxillary alveolar bone microarchitecture. Most of the actions of estrogen in long bones occur via estrogen receptor α (ERα). However, the function of ERα in the maxillary bone has not been defined. We aimed to investigate the role and underlying mechanisms of ERα in the physiological and mechanically induced alveolar bone remodeling in female and male mice. Wild-type (WT) and ERα−/− (ERKOα) mice were subjected to mechanically stimulated bone remodeling by inducing orthodontic tooth movement (OTM). The maxillary bone was analyzed using histomorphometric analysis, micro–computed tomography, quantitative polymerase chain reaction, and energy-dispersive spectroscopy. Bone marrow cells (BMCs) from WT and ERKOα mice were tested for their capacity to differentiate into osteoblasts and osteoclasts. Both male and female ERKOα mice exhibited marked reduction of alveolar bone mass and increased OTM. This response was associated with an increased number of osteoclasts and reduced number of apoptotic cells and osteoblasts in the periodontium and alveolar bone. Consistently, ERKOα mice exhibited lower levels of calcium in bone and increased expression of IL-33 (interleukin-33), TNF-α (tumor necrosis factor α), and IL-1β (interleukin-1β) and decreased expression of dentin matrix acidic phosphoprotein and alkaline phosphatase in periodontal tissues. Moreover, the differentiation of osteoclasts and osteoblasts in vitro was significantly higher in BMCs obtained from ERKOα. ERα is required to maintain the microarchitecture of maxillary alveolar bone. This process is linked to bone cell differentiation and apoptosis, as well as local production of inflammatory molecules such as IL-33, TNF-α, and IL-1β.

Características produtivas de cordeiros terminados em confinamento com dietas contendo diferentes teores de borra de soja

Avaliou-se o efeito de dietas contendo diferentes teores de borra de soja sobre o consumo de nutrientes, o ganho de peso, as características de carcaça e os componentes do peso vivo de cordeiros terminados em confinamento. Foram utilizados 25 cordeiros, machos, castrados, da raça Texel, distribuídos aleatoriamente em cinco tratamentos compostos por proporções de 0%, 2,89%, 5,77%, 8,65% ou 11,55% de borra de soja na matéria seca das dietas. Houve redução linear do consumo de nutrientes, com exceção do consumo de extrato etéreo, que aumentou linearmente. O peso vivo ao abate, o ganho de peso diário, os pesos e rendimentos de carcaça quente e fria, e os pesos de perna e de costilhar diminuíram linearmente, ao passo que as proporções de rúmen e do trato gastrintestinal, com conteúdo, bem como o conteúdo gastrointestinal, aumentaram linearmente com o aumento dos níveis de borra de soja nas dietas. A proporção de perna foi influenciada de forma quadrática. O aumento da participação de borra de soja na dieta de cordeiros em sistema de confinamento leva à diminuição do desempenho produtivo dos animais. Contudo, o lucro diário obtido por animal não é influenciado, podendo-se inferir que a inclusão de borra de soja até o nível de 11,55% da matéria seca total da dieta é uma alternativa viável para a terminação de cordeiros em confinamento.

Comportamento ingestivo de cordeiros Texel e ideal alimentados com casca de soja

O presente experimento, conduzido no laboratório de ovinocultura da Universidade Federal de Santa Maria, teve como objetivo avaliar o comportamento ingestivo de cordeiros das raças Texel e Ideal, terminados em confinamento com dietas contendo diferentes teores de casca de soja em substituição da silagem de sorgo. Foram utilizados 40 cordeiros machos não castrados, sendo 20 provenientes da raça Texel e 20 da raça Ideal, desmamados aproximadamente aos 50 dias e confinados em baias individuais, distribuídos aleatoriamente em quatro grupos de acordo com o nível de inclusão de casca de soja na dieta: 0 %, 33,5 %, 66,5 % e 100 % de casca de soja em substituição a silagem de sorgo. O tempo despendido em atividades de alimentação, tempo de mastigação total e o tempo gasto por refeição diminuíram linearmente, enquanto que o período de ócio e a eficiência de alimentação e de ruminação aumentaram linearmente, com o aumento do nível de substituição de silagem de sorgo por casca de soja. Cordeiros da raça Texel permaneceram por mais tempo em atividades de ruminação e de mastigação total, gastaram mais tempo por refei-ção, permaneceram menos tempo em ócio e apresentaram menor eficiência de ruminação quando comparados com cordeiros da raça Ideal, quando confinados em fase de terminação.

Microbial contamination of toothbrushes and their decontamination

PURPOSE

The objective was to determine the level of contamination of toothbrushes by mutans streptococci using microbiological identification, to access the bacterial contamination using scanning electron microscopy (SEM) and to evaluate the efficacy of two toothbrush disinfectants.

METHODS

Nineteen children used their toothbrushes once a day, for five consecutive days. The toothbrushes were then immersed into disinfectant solutions for 20 h: Group I--0.12% chlorhexidine gluconate; Group II--1% sodium hypochlorite; Group III--sterile tap water. They were then placed into test tubes containing CaSa B, for 3 to 4 days at 37 degrees C. The number of MS cfu was counted and the toothbrushes were submitted to SEM analysis.

RESULTS

There was no bacterial growth in Groups I and II; Group III showed MS growth (range, 21 to 120 cfu). Scanning electron microscopy showed biofilm formation on toothbrush bristles.

CONCLUSION

Immersion in 0.12% chlorhexidine gluconate and 1% sodium hypochlorite are efficient methods for toothbrush disinfection.

Changes in psychopathology of parents of NOFT (non-organic failure to thrive) infants during treatment

This clinical case-study of 50 infants suffering from NOFT (non-organic failure to thrive) and their parents supports the idea that the feeding problem is intimately related to parental disorders. We find a high rate (70%) of parental psychopathology (axis I diagnosis applying DSM-III-R) at the time of referral and a significant reduction (to 37%) during treatment of the infants and their parents. After a year only 12% of the parents were diagnosed with psychiatric disorders. In contrast personality disorders (axis II diagnosis applying DSM-III-R) show more stability and can be regarded as a trait variable, whereas the psychiatric disorders are of a more reactive nature. These conclusions may be influenced somewhat by the strictly hospital based design of our pilot study (infants and parents contacted only after clinical referral) and by inclusion only of firstborn infants. Nevertheless, they point to the psychopathology of parents as a main cause for non-organic failure to thrive. Psychopathological traits such as severe attachment behavior problems and primary bonding difficulties may have been latent and only became manifest due to the task of nurturing an infant for the first time.