Biology subjects

Perretti, M.

Publications and source records attributed to Perretti, M..

9 recordsLinked to original sources

bioRxiv2025

PI3Kδ Bridges Microbial Surveillance with Antigen Presentation to Reinforce Intestinal Immunity

Phosphoinositide 3-kinase delta (PI3K{delta}) is essential for immune cell functions, preventing immunodeficiency and inflammation; however, its role in dendritic cell (DC)-mediated immune regulation remains unknown. Here, we report a key role for DC-intrinsic PI3K{delta} in linking microbial recognition with antigen presentation for effective T-cell priming. Using genetic and functional assays, we demonstrate that PI3K{delta} deficiency in DCs leads to broad dysregulation of intestinal CD4 T-cell immunity, characterized by impaired regulatory T-cell expansion and increased susceptibility to colitis. DC-based studies show that PI3K{delta} links pattern-recognition-receptor signaling to MHC class I- and II-restricted presentation of phagosome-associated antigens by facilitating NOX2-dependent oxidative burst through RAC2, while mitigating inflammasome activation. In contrast, PI3K{delta} deficiency disrupts phagosomal pH balance, leading to accelerated acidification and proteolysis of antigens, impairing T-cell activation. Our study identifies PI3K{delta} as a key coordinator of phagosome dynamics, important for DC adaptive programming that shapes T-cell responses and supports intestinal immune homeostasis.

immunology↗

bioRxiv2025

Formyl-peptide receptor type 2 activation mitigates secondary organ damage in inflammatory arthritis

Rheumatoid arthritis (RA) is associated with heart and lung dysfunction. Current therapies fail to attenuate such complications. Here, we identify formyl-peptide receptor type 2 (FPR2) as therapeutic target to treat heart and lung dysfunction associated with inflammatory arthritis. Arthritic mice on high levels of dietary homocysteine develop cardiac diastolic dysfunction and reduced lung compliance, mirroring two comorbidities in RA. Therapeutic administration of a small molecule FPR2 agonist (BMS986235) to hyper-homocysteine arthritic mice prevented diastolic dysfunction (monitored by echocardiography) and restored lung compliance. These tissue-specific effects were secondary to reduced neutrophil infiltration, modulation of fibroblast activation and phenotype (in the heart) and attenuation of monocyte and macrophage numbers (in the lung). A dual FPR1/2 agonist (compound 43) failed to prevent the reduction in lung compliance of arthritic mice and promoted accumulation of inflammatory monocytes and pro-fibrotic macrophages in lung parenchyma. This cellular response lies downstream of FPR1-mediated potentiation of CCL2-dependent monocyte chemotaxis and activation. This finding supports therapeutic development of selective FPR2 agonists to mitigate two impactful comorbidities associated with inflammatory arthritides.

pharmacology and toxicology↗

bioRxiv2022

Placental inflammation leads to abnormal embryonic heart development

Placental and embryonic heart development occurs in parallel, and these organs have been proposed to exert reciprocal regulation during gestation. Poor placentation has been associated with congenital heart disease (CHD), an important cause of infant mortality. However, the mechanisms by which altered placental development can lead to CHD remain unresolved. In the current study we show that neutrophil-driven placental inflammation leads to inadequate placental development and loss of barrier function. Consequently, placental inflammatory monocytes of maternal origin become capable to migrate to the embryonic heart and alter the normal composition of resident cardiac macrophages and cardiac tissue structure. This cardiac impairment continues into postnatal life, hindering normal tissue architecture and function. Finally, we demonstrate that tempering placental inflammation can rescue this fetal cardiac defect and is sufficient to promote normal cardiac function in postnatal life. Taken together, our observations provide a mechanistic paradigm whereby neutrophil-driven inflammation in pregnancy can preclude normal embryonic heart development as a direct consequence of poor placental development.

immunology↗

bioRxiv2021

Targeting the Annexin A1-FPR2/ALX pathway for host-directed therapy in dengue disease

Host immune responses contribute to dengues pathogenesis and severity, yet the possibility that failure in endogenous inflammation resolution pathways could characterise the disease has not been contemplated. The pro-resolving protein Annexin A1 (AnxA1) is known to counterbalance overexuberant inflammation and mast cell (MC) activation. We hypothesised that inadequate AnxA1 engagement underlies the cytokine storm and vascular pathologies associated with dengue disease. Levels of AnxA1 were examined in the plasma of dengue patients and infected mice. Immunocompetent, IFN/{beta}R-/-, AnxA1-/- and FPR2/ALX-/- mice were infected with Dengue virus (DENV) and treated with the AnxA1 mimetic peptide Ac2-26 for analysis. Additionally, the effect of Ac2-26 on DENV-induced MC degranulation was assessed in vitro and in vivo. We observed that circulating levels of AnxA1 were reduced in dengue patients and DENV-infected mice. While the absence of AnxA1 or its receptor FPR2/ALX aggravated illness in infected mice, treatment with AnxA1 agonistic peptide attenuated disease manifestations. Both clinical outcomes were attributed to modulation of DENV-mediated viral load-independent MC degranulation. We have thereby identified that altered levels of the pro-resolving mediator AnxA1 are of pathological relevance in DENV infection, suggesting FPR2/ALX agonists as a therapeutic target for dengue disease.

microbiology↗

bioRxiv2021

The Immunomodulatory Effects of Social Isolation in Mice are Linked to Temperature Control

Living in isolation is considered an emerging societal problem that negatively affects the physical wellbeing of its sufferers in ways that we are just starting to appreciate. This study investigates the immunomodulatory effects of social isolation in mice, utilising a two-week program of sole cage occupancy followed by the testing of immune-inflammatory resilience to bacterial sepsis. Our results revealed that mice housed in social isolation showed an increased ability to clear bacterial infection compared to control socially housed animals. These effects were associated with specific changes in whole blood gene expression profile and an increased production of classical pro-inflammatory cytokines. Interestingly, equipping socially isolated mice with artificial nests as a substitute for their natural huddling behaviour reversed the increased resistance to bacterial sepsis. These results further highlight the ability of the immune system to act as a sensor of our living conditions and to respond in a compensatory fashion to external challenges that might threaten the survival of the host.

immunology↗

bioRxiv2020

The Atlas of Inflammation-Resolution (AIR)

Acute inflammation is a protective reaction by the immune system in response to invading pathogens or tissue damage. Ideally, the response should be localized, self-limited, and returning to homeostasis. If not resolved, acute inflammation can result in organ pathologies leading to chronic inflammatory phenotypes. Acute inflammation and inflammation resolution are complex coordinated processes, involving a number of cell types, interacting in space and time. The biomolecular complexity and the fact that several biomedical fields are involved, make a multi and interdisciplinary approach necessary. This Atlas of Inflammation Resolution (AIR) is a web-based resource capturing the state-of-the-art in acute inflammation and inflammation resolution research. The AIR provides an interface for users to search thousands of interactions, arranged in inter-connected multi-layers of process diagrams, covering a wide range of clinically relevant phenotypes. The AIR serves as an open access knowledgebase, including a gateway to numerous public databases. It is furthermore possible for the user to map experimental data onto the molecular interaction maps of the AIR, providing the basis for bioinformatics analyses and systems biology approaches. By mapping experimental data onto the Atlas, it can be used to elucidate drug action as well as molecular mechanisms underlying different disease phenotypes. For the visualization and exploration of information, the AIR uses the Minerva platform, which is a well-established tool for the presentation of disease maps. The molecular details of the AIR are encoded using international standards. The Atlas of Inflammation Resolution was created as a freely accessible resource, supporting research and education in the fields of acute inflammation and inflammation resolution. The AIR connects research communities, facilitates clinical decision making, and supports research scientists in the formulation and validation of hypotheses.

immunology↗

bioRxiv2019

Extracellular vesicles from monocyte/platelet aggregates modulate human atherosclerotic plaque responses

In atherosclerosis, a chronic disease characterized by lipid accumulation, fibrosis and vascular inflammation, extracellular vesicles (EVs) are emerging as key players in different stages of disease development. Here we provide evidence that EVs released by mixed aggregates of monocytes and platelets in response to TNF- are both CD14+ and CD41+. Tempering platelet activation with Iloprost impacted the quality and quantity of EV produced. Proteomics of EVs from cells activated with TNF- alone or in presence Iloprost revealed distinct proteome, with selective hits like gelsolin. EVs from TNF- stimulated monocytes augmented release of cytokines, and modulated more than 500 proteins by proteomics, when added to human atherosclerotic plaques. In contrast, EVs generated by TNF- and Iloprost produced minimal plaque activation. In conclusion, attenuating platelet activation has an effect on EV composition released from monocyte/platelet aggregates with downstream modulation of their pro-inflammatory actions and contribution to the development and progression of atherosclerosis.

immunology↗

bioRxiv2019

Immuno-moodulin: a new anxiogenic factor produced by autoimmune-prone T cells

Patients suffering from autoimmune diseases are more susceptible to mental disorders yet, the existence of specific cellular and molecular mechanisms behind the co-morbidity of these pathologies is far from being fully elucidated. By generating transgenic mice overexpressing Annexin-A1 exclusively in T cells to study its impact in models of autoimmune diseases, we made the unpredicted observation of an increased level of anxiety. Gene microarray of Annexin-A1 CD4+ T cells identified a novel anxiogenic factor, a small protein of approximately 21kDa encoded by the gene 2610019F03Rik which we named Immuno-moodulin. Neutralizing antibodies against Immuno-moodulin reverted the behavioral phenotype of Annexin-A1 transgenic mice and lowered the basal levels of anxiety in wild type mice; moreover, we also found that patients suffering from obsessive compulsive disorders show high levels of Imood in their peripheral mononuclear cells. We thus identify this protein as a novel peripheral determinant that modulates anxiety behavior. Therapies targeting Immuno-moodulin may lead to a new type of treatment for mental disorders through regulation of the functions of the immune system, rather than directly acting on the nervous system.

immunology↗

bioRxiv2018

Annexin A1 drives macrophage skewing towards a resolving phenotype to accelerate the regeneration of muscle injury through AMPK activation

Understanding the circuits that promote an efficient resolution of inflammation is crucial to deciphering the molecular and cellular processes required to promote tissue repair. Macrophages play a central role in the regulation of inflammation, resolution and repair/regeneration. Using a model of skeletal muscle injury and repair, herein we identify Annexin A1 (AnxA1) as the extracellular trigger of macrophage skewing towards a pro-reparative phenotype. Brought into the injured tissue initially by migrated neutrophils, and then over-expressed in infiltrating macrophages, AnxA1 activates FPR2/ALX receptors and the downstream AMPK signalling cascade leading to macrophage skewing, dampening of inflammation and regeneration of muscle fibres. Mice lacking AnxA1 in all cells or in myeloid cells only display a defect in this reparative process. In vitro experiments recapitulated these properties, with AMPK null macrophages lacking AnxA1-mediated polarization. Collectively, these data identify the AnxA1/FPR2/AMPK axis as a novel pathway in skeletal muscle injury regeneration.

cell biology↗