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Fibrin is a major component of the provisional extracellular matrix formed during tissue repair following injury, and enables cell infiltration and anchoring at the wound site. ...Macrophages are dynamic regulators of this process, advancing and resolving inflammation in response to cues in their microenvironment. Although much is known about how soluble factors such as cytokines and chemokines regulate macrophage polarization, less is understood about how insoluble and adhesive cues, specifically the blood coagulation matrix fibrin, influence macrophage behavior. In this study, we observed that fibrin and its precursor fibrinogen elicit distinct macrophage functions. Culturing macrophages on fibrin gels fabricated by combining fibrinogen with thrombin stimulated secretion of the anti-inflammatory cytokine, interleukin-10 (IL-10). In contrast, exposure of macrophages to soluble fibrinogen stimulated high levels of inflammatory cytokine tumor necrosis factor alpha (TNF-α). Macrophages maintained their anti-inflammatory behavior when cultured on fibrin gels in the presence of soluble fibrinogen. In addition, adhesion to fibrin matrices inhibited TNF-α production in response to stimulation with LPS and IFN-γ, cytokines known to promote inflammatory macrophage polarization. Our data demonstrate that fibrin exerts a protective effect on macrophages, preventing inflammatory activation by stimuli including fibrinogen, LPS, and IFN-γ. Together, our study suggests that the presentation of fibrin(ogen) may be a key switch in regulating macrophage phenotype behavior, and this feature may provide a valuable immunomodulatory strategy for tissue healing and regeneration.
Fibrin is a fibrous protein resulting from blood clotting and provides a provisional matrix into which cells migrate and to which they adhere during wound healing. Macrophages play an important role in this process, and are needed for both advancing and resolving inflammation. We demonstrate that culture of macrophages on fibrin matrices exerts an anti-inflammatory effect, whereas the soluble precursor fibrinogen stimulates inflammatory activation. Moreover, culture on fibrin completely abrogates inflammatory signaling caused by fibrinogen or known inflammatory stimuli including LPS and IFN-γ. Together, these studies show that the presentation of fibrin(ogen) is important for regulating a switch between macrophage pro- and anti-inflammatory behavior.
Macrophages are innate immune cells that adhere to the extracellular matrix within tissues. However, how matrix properties regulate their function remains poorly understood. Here, we report that the ...adhesive microenvironment tunes the macrophage inflammatory response through the transcriptional coactivator YAP. We find that adhesion to soft hydrogels reduces inflammation when compared to adhesion on stiff materials and is associated with reduced YAP expression and nuclear localization. Substrate stiffness and cytoskeletal polymerization, but not adhesive confinement nor contractility, regulate YAP localization. Furthermore, depletion of YAP inhibits macrophage inflammation, whereas overexpression of active YAP increases inflammation. Last, we show in vivo that soft materials reduce expression of inflammatory markers and YAP in surrounding macrophages when compared to stiff materials. Together, our studies identify YAP as a key molecule for controlling inflammation and sensing stiffness in macrophages and may have broad implications in the regulation of macrophages in health and disease.
Adenosine mediates immunosuppression within the tumor microenvironment through triggering adenosine 2A receptors (A2AR) on immune cells. To determine whether this pathway could be targeted as an ...immunotherapy, we performed a phase I clinical trial with a small-molecule A2AR antagonist. We find that this molecule can safely block adenosine signaling
. In a cohort of 68 patients with renal cell cancer (RCC), we also observe clinical responses alone and in combination with an anti-PD-L1 antibody, including subjects who had progressed on PD-1/PD-L1 inhibitors. Durable clinical benefit is associated with increased recruitment of CD8
T cells into the tumor. Treatment can also broaden the circulating T-cell repertoire. Clinical responses are associated with an adenosine-regulated gene-expression signature in pretreatment tumor biopsies. A2AR signaling, therefore, represents a targetable immune checkpoint distinct from PD-1/PD-L1 that restricts antitumor immunity. SIGNIFICANCE: This first-in-human study of an A2AR antagonist for cancer treatment establishes the safety and feasibility of targeting this pathway by demonstrating antitumor activity with single-agent and anti-PD-L1 combination therapy in patients with refractory RCC. Responding patients possess an adenosine-regulated gene-expression signature in pretreatment tumor biopsies.
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Macrophages are versatile cells of the innate immune system that can adopt a variety of functional phenotypes depending on signals in their environment. In previous work, we found that culture of ...macrophages on fibrin, the provisional extracellular matrix protein, inhibits their inflammatory activation when compared to cells cultured on polystyrene surfaces. Here, we sought to investigate the role of matrix stiffness in the regulation of macrophage activity by manipulating the mechanical properties of fibrin. We utilize a photo-initiated crosslinking method to introduce dityrosine crosslinks to a fibrin gel and confirm an increase in gel stiffness through active microrheology. We observe that matrix crosslinking elicits distinct changes in macrophage morphology, integrin expression, migration, and inflammatory activation. Macrophages cultured on a stiffer substrate exhibit greater cell spreading and expression of αM integrin. Furthermore, macrophages cultured on crosslinked fibrin exhibit increased motility. Finally, culture of macrophages on photo-crosslinked fibrin enhances their inflammatory activation compared to unmodified fibrin, suggesting that matrix crosslinking regulates the functional activation of macrophages. These findings provide insight into how the physical properties of the extracellular matrix might control macrophage behavior during inflammation and wound healing.
Leukocyte‐associated immunoglobulin‐like receptor‐1 (LAIR‐1) is an inhibitory receptor broadly expressed on immune cells, with its ligands residing within the extracellular matrix protein collagen. ...In this study, surfaces are modified with a LAIR‐1 ligand peptide (LP), and it is observed that macrophages cultured on LAIR‐1 LP‐conjugated surfaces exhibit significantly reduced secretion of inflammatory cytokines in response to proinflammatory stimuli that reflect an injured environment. These downregulated mediators include TNF‐α, MIP‐1α, MIP‐1β, MIP‐2, RANTES, and MIG. Knockdown of LAIR‐1 using siRNA abrogates this inhibition of cytokine secretion, supporting the specificity of the inhibitory effect to this receptor. These results are the first to demonstrate that integration of LAIR‐1 ligands with biomaterials could suppress inflammatory responses.
Modification of material surfaces with a ligand peptide for immune inhibitory receptor, leukocyte‐associated immunoglobulin‐like receptor‐1 (LAIR‐1), significantly reduces the secretion of inflammatory cytokines of macrophages in response to proinflammatory stimuli. The LAIR‐1 ligand peptide is derived from the extracellular matrix protein collagen, and the incorporation of this ligand peptide to biomaterial surfaces may be a strategy to suppress local inflammatory responses toward implanted materials.
The present study reports on the development and testing of novel bleaching agents containing co-doped metaloxide nanoparticles (NP; 0%, 5%, 10% v/w) and hydrogen peroxide (HP, 0%, 6%, 15%, and 35%). ...Bovine blocks (n = 200, A = 36 mm2) were obtained and randomly distributed into experimental groups (n = 10/group). NPs were incorporated into gels before bleaching (3 sessions, 7 days apart, 30 min/session, irradiated with violet light-LT). Color changes (ΔE00, ΔWID), mineral content (CO32−, PO43−), and topography were assessed (spectrophotometer, ATR-FTIR, and AFM) before and after bleaching procedures (14 days). Metabolic status and three-dimensional components of non-disrupted Streptococcus mutans biofilms were investigated using a multimode reader and confocal microscopy. The results indicate that ΔE00 and ΔWID significantly increased with NPs’ concentrations and LT. The enamel’s mineral ratio was adversely impacted by HP, but alterations were less pronounced when using NP-containing gels. The enamel’s topography was not damaged by the bleaching protocols tested. The bioluminescence results show that bleaching protocols do not render latent antibacterial properties to enamel, and the confocal microscopy results demonstrate that the 3-dimensional distribution of the components was affected by the protocols. The proposed nanotechnology improved the bleaching efficacy of experimental materials independent of hydrogen peroxide or irradiation and did not adversely impact the enamel’s surface properties or its chemical content.
Abstract
Elder abuse (EA) has been recognized as a serious public health concern. Recent studies have found that approximately 10% of community-dwelling, cognitively intact older adults experience ...some form of EA each year. Although EA research has made substantial progress, EA is often under-reported, with only an estimated 15% of cases being reported to formal support services. One of the main reasons for the under-reporting of EA is the victims’ feelings of shame, which have been shown to be exacerbated when the perpetrator is a family member and/or an individual with whom the older adults have close trusting relationships. Qualitative interviews conducted with 12 older adult (parent) and adult child caregiver dyads (n=24) revealed that older adults who experience EA by their adult children experience intense shame. Thematic analysis focused on what led to these feelings of shame, and this resulted in four main themes: (1) Failure in their role as a parent; (2) Adult children viewing them as powerless and unworthy; (3) Experiencing negative psychological effects; and (4) Self-blame. With a sense of responsibility to protect their family, older adults tend to keep ‘family shame’ to themselves, leading to a reluctance to disclose EA. As spouses and adult children, the two most common caregiving types, have also been reported to be the two most common groups of EA perpetrators, gaining a better understanding of the root causes of shame can help to support older adults in living safely in their homes and communities for as long as possible.
Background/Objectives:
Resident-to-resident aggression (RRA) is a prevalent form of interpersonal violence in long-term care (LTC) settings. Research to guide preventive interventions is limited. ...Using social-ecological and need-driven dementia-compromised behavior perspectives, we sought to generate process models representing common RRA pathways in dementia-specific LTC units.
Research Methods:
We used qualitative focus group methodology involving staff (n = 36) exposed to everyday resident interactions at two urban LTC facilities in Toronto, Canada. Semistructured interviews were audio-recorded and transcribed. Two independent raters coded the transcripts using iterative, constant comparison analytic processes.
Results:
Two distinct RRA process models in dementia-specific LTC units were developed. Models reflect sequential pathways driven by residents’ benign or responsive behaviors and cognitive processing limitations, with escalation points within resident dyads or groups.
Implications:
This study furthers RRA conceptualization as a process rather than an aggressive event. Models capture unique RRA manifestations in dementia-specific LTC units and entrypoints for prevention or management.
Abstract
Elder mistreatment, often understood in the context of abuse and neglect, is a growing concern for the health and wellbeing of seniors and their families. A 2015 Canadian prevalence study by ...the National Initiative for the Care of the Elderly (NICE) found that seniors who are mistreated are more willing to talk to other seniors, rather than clinicians, police or family. However, a lack of knowledge, access to resources, and community stigma may limit seniors’ abilities to address mistreatment.This study evaluated the impact on knowledge, attitudes, and behaviours of having seniors deliver workshops on mistreatment to other seniors. A Seniors’ Advisory Committee developed content for these workshops, delivered by seniors in sixteen communities across Ontario, Canada. Participants completed pre/post-surveys assessing changes in knowledge, attitudes, and behaviours. Results indicate that workshops effectively increased awareness of mistreatment issues among participants, on average, by 37%. Participants experienced a 44% increase in their perceived preparation to provide information to another older adult asking about mistreatment. Barriers to help-seeking among seniors include finding trustworthy sources, fear of retaliation, and a lack of legal protection. Prior to the training, healthcare providers were the main sources of information for participants (58%); depending on the severity of the situation, 60% of participants indicated eventually reporting to police, who are not the preferred source of information. Senior-led workshops about mistreatment appear to be effective for increasing knowledge and encouraging disclosure and help-seeking behaviours. Results support prevention models that empower seniors to educate other seniors on issues around mistreatment.
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