Biology subjects

Pelegrin, P.

Publications and source records attributed to Pelegrin, P..

9 recordsLinked to original sources

bioRxiv2025

ND-13, a DJ-1 derived peptide, as a novel pharmacological approach in the prevention of NLRP3 inflammasome activity in Diabetic Nephropathy

Diabetic nephropathy is the most important cause of renal failure worldwide and is characterized by sustained inflammation regulated in part by NLRP3 Inflammasome. Attenuation of inflammation is a major priority to prevent renal damage. Our previous publications show that DJ-1 has antioxidant and anti-inflammatory properties in the kidney. ND-13 is a short peptide consisting of 13 amino acids of the DJ-1-protein, which could increase DJ-1 pathway activation. The aim of these studies was to determine the role of NLRP3 in the pathogenesis of diabetic nephropathy and to study the possible renal protective effects of the DJ-1 pathway in diabetic mice and on inflammasome regulation. Bone marrow derived macrophages were treated with ND-13 and cultivated in high and low glucose. Diabetes was induced in C57Bl/6 mice via injection of streptozotocin and treated with ND-13 and MCC950, an inhibitor of the NLRP3 inflammasome. Peripheral mononuclear cells were isolated from human with diabetes, diabetic nephropathy and healthy donors and were plated, pretreated with ND-13 and stimulated with LPS+ATP. IL-1{beta} concentration in the medium of bone marrow derived macrophages increased by NLRP3 inflammasome stimulation by LPS+ATP, and decreased in macrophages pre-treated with ND-13, however, in the presence of LPS+Nigericin no effect was found. Peritoneal macrophages from diabetic mice were obtained and plated. Streptozotocin-induced diabetic C57BL/6 mice have increased the peritoneal cells IL-1{beta} production compared with control mice, suggesting that inflammasome may be activated in macrophages during diabetes and that ND-13 treatment normalized its activity. ND-13 and MCC950 decreased histologic evidence of tubular injury in STZ-induced diabetes in mice, additionally, significantly increased the mRNA expression of Col-I, Col-II, Tgf-{beta}, Il-6, Tnf- and P2x7 in the renal cortex, which was partially prevented by ND-13 and MCC950 pre-treatment. P2x7 mRNA expression was also increased in peritoneal macrophages obtained from diabetic mice, and its expression was attenuated by ND-13 pre-treatment. Peripheral mononuclear cells isolated from patients blood were plated and stimulated with LPS+ATP. Patients with diabetic nephropathy presented a significant increase of IL-1{beta} release compared to diabetic individuals and ND-13 could has a role in the prevention of inflammasome activation in healthy patients. Our results demonstrate that activation of the DJ-1 pathway is a promising approach to prevent renal inflammation and fibrosis during diabetes, by ameliorating inflammasome activation in peripheral immune cells. Thus, ND-13 could be a promising new therapeutic approach to attenuating inflammation and renal damage in diabetic nephropathy.

cell biology↗

bioRxiv2025

The inflammasome adaptor protein ASC triggers immunometabolic dysregulation induced by dysbiosis during obesity

The inflammasomes are a component of the innate immune system that induce inflammation after activation by danger and pathogen signals, this process is of extreme importance in the gut, where high-saturated fat diets modulate inflammasome activity resulting in dysbiosis and inflammation. In this work, we found that the common inflammasome adaptor protein, apoptosis speck-like protein with a caspase activation domain (ASC), is essential for the development of metabolic dysregulation during high fat diet. ASC-deficient mice (Pycard-/-) presented lower weight gain and improved glucose tolerance, enhancing metabolism, and reducing inflammation in both intestine and liver. The extracellular administration of ASC oligomers to Pycard-/- mice partially rescued dysbiosis, intestinal metabolism and inflammation. Therefore, ASC presents intracellular functions activating the inflammasome, as well as extracellular function as an oligomer during metabolic dysregulation, emerging ASC as a potential drug target beneficial to treat obesity and metabolism-associated liver diseases.

immunology↗

bioRxiv2024

Gasdermin D mediates a fast transient release of ATP after NLRP3 inflammasome activation before ninjurin 1-induced lytic cell death

Pyroptosis is a lytic cell death triggered by the cleavage of gasdermin (GSDM) proteins and subsequent pore formation by the N-terminal domain oligomerization in the plasma membrane. GSDMD is cleaved by caspase-1/-4/-5/-11 upon inflammasome activation and mediates IL-1{beta} and IL-18 release. GSDMD pores favors ninjurin-1 (NINJ1) induced plasma membrane rupture and cell death. Here, we demonstrate that GSDMD mediates early ATP release upon NLRP3 inflammasome activation independently of NINJ1, occurring before IL-1{beta} release and cell death and constituting an early danger signal. The release of ATP is a transient signal terminated before the cells continue to permeabilize and die. The different N-terminal of GSDMA to E are also able to release ATP and induce monocyte migration towards pyroptotic cells. This study reveals ATP release as an early, and transient danger signal depending on GSDMD plasma membrane permeabilization, independently of the late stages of lytic cell death.

immunology↗

bioRxiv2024

Cardiolipin Inhibits the Noncanonical Inflammasome by Preventing LPS Binding to Caspase 4/11 to Mitigate Endotoxemia in Vivo

In Gram-negative bacterial sepsis, excessive caspase 4/11 activation in response to circulating bacterial lipid LPS (endotoxemia) can cause organ damage and mortality. Current inhibitors of caspase 4/11 also block caspase 1 activity and are therefore not appealing clinical candidates for treating Gram-negative sepsis. Here, we identify double-unsaturated 18:2 cardiolipin as a selective inhibitor of caspase 4/11-dependent inflammatory cytokine secretion and pyroptosis, without affecting caspase-1 responses. Cardiolipin targets the CARD domain of caspase 4/11, impeding its interaction with LPS to restrain caspase 4/11 activation, thereby suppressing endotoxemia-induced systemic inflammation in vivo. Thus, we present cardiolipin as a promising candidate for preventing endotoxemia- induced sequelae in sepsis while preserving caspase-1-driven anti-microbial immune responses. By identifying cardiolipin as a specific caspase 4/11 inhibitor, we provide an urgently-needed tool for studying caspase 4/11 functions in inflammatory pathways, and open the way to studies of noncanonical inflammasome regulation by endogenous cardiolipin.

immunology↗

bioRxiv2022

Soluble P2X7 receptor is elevated in the plasma of COVID-19 patients and correlates with disease severity

Inflammation is a tightly coordinated response against bacterial and viral infections, triggered by the production of pro-inflammatory cytokines. SARS-CoV-2 infection induces COVID-19 disease, characterized by an inflammatory response mediated through the activation of the NLRP3 inflammasome, which results in the production of IL-1{beta} and IL-18 along with pyroptotic cell death. The NLRP3 inflammasome could be also triggered by sterile danger signals such as extracellular ATP triggering the purinergic P2X7 receptor. Severe inflammation in the lungs of SARS-CoV-2 infected individuals is associated with pneumonia, hypoxia and acute respiratory distress syndrome, these being the causes of death associated with COVID-19. Both the P2X7 receptor and NLRP3 have been considered as potential pharmacological targets for treating inflammation in COVID-19. However, there is no experimental evidence of the involvement of the P2X7 receptor during COVID-19 disease. In the present study we determined the concentration of different cytokines and the P2X7 receptor in the plasma of COVID-19 patients and found that along with the increase in IL-6, IL-18 and the IL-1 receptor antagonist in the plasma of COVID-19 patients, there was also an increase in the purinergic P2X7 receptor. Increase in COVID-19 severity and C-reactive protein concentration positively correlated with increased concentration of the P2X7 receptor in the plasma, but not with IL-18 cytokine. The P2X7 receptor was found in the supernatant of human peripheral blood mononuclear cells after inflammasome activation. Therefore, our data suggest that determining levels of the P2X7 receptor in the plasma could be a novel biomarker of COVID-19 severity.

immunology↗

bioRxiv2022

Ornithine Lipid Activates Both TLR4 and the non-canonical NLRP3 Inflammasome.

Myeloid cells recognise Gram-negative bacterial lipopolysaccharides (LPS). LPS recognition triggers inflammatory reactions through Toll-like receptor 4 (TLR4) and primes the cells for inflammasome activation. In phosphate-depleted environments, bacteria cannot produce LPS. Instead, they increase their synthesis of ornithine lipid (OL), which is constitutively present in some pathogenic Gram-negative and -positive bacteria but absent in commensals. OL is implicated in bacterial pathogenicity, but the mechanism is unclear. Using primary murine macrophages and human peripheral blood mononuclear cells, we identify OL as a partial TLR4 agonist and an NLRP3 inflammasome activator. For this, OL directly activates TLR4 and indirectly activates NLRP3 in a potassium-efflux-dependent manner. OL also upregulates the expression of NLRP3 and pro-IL-1{beta} and induces cytokine secretion in primed and unprimed cells. By contrast, in the presence of LPS, OL functions as a partial TLR4 antagonist; LPS-induced TLR4 activation and inflammasome priming are inhibited by OL, leading to reduced TNF and IL-1{beta} secretion. We thus suggest that in phosphate-depleted environments, OL replaces LPS bacterial immunogenicity while constitutively present OL may allow bacteria to escape immune surveillance.

immunology↗

bioRxiv2021

Galvanic current activates the NLRP3 inflammasome to promote type I collagen production in tendon

The NLRP3 inflammasome coordinates inflammation in response to different pathogen- and damage-associated molecular patterns, being implicated in different infectious, chronic inflammatory, metabolic and degenerative diseases. In chronic tendinopathies lesions, different non-resolving mechanisms produce a degenerative condition that impairs tissue healing, complicating their clinical management. Percutaneous needle electrolysis consist in the application of a galvanic current and is emerging as a novel treatment for tendinopathies. Here we found that galvanic current activates the NLRP3 inflammasome and the induction of an inflammatory response promoting a collagen-mediated regeneration of the tendon. This study establish the molecular mechanism of percutaneous electrolysis for the treatment of chronic lesions and the beneficial effects of an induced inflammasome-related response.

immunology↗

bioRxiv2021

Full-length NLRP3 forms oligomeric cages to mediate NLRP3 sensing and activation

The nucleotide-binding domain and leucine-rich-repeat (LRR) containing protein 3 with a pyrin domain (NLRP3) is emerging to be a critical intracellular inflammasome sensor of membrane integrity and a highly important clinical target against chronic inflammation. Here we report that the endogenous, stimulus-responsive form of full-length NLRP3 is a 12-16 mer double ring cage held together by LRR-LRR interactions with the pyrin domains shielded within the assembly to avoid premature activation. Surprisingly, this NLRP3 form is predominantly membrane localized, which is consistent with previously noted localization of NLRP3 at various membrane organelles. Structure-guided mutagenesis reveals that trans-Golgi network dispersion into vesicles, an early event observed for all NLRP3 activating stimuli, requires the double ring cages of NLRP3. Double ring-defective NLRP3 mutants further abolish inflammasome punctum formation, caspase-1 processing and cell death. Thus, unlike other inflammasome sensors that are monomeric when inactive, our data uncover a unique NLRP3 oligomer on membrane that is poised to sense diverse signals to induce inflammasome activation.

immunology↗

bioRxiv2020

ASC oligomer favor caspase-1CARD domain recruitment after intracellular potassium efflux

Signaling through the inflammasome is important for the inflammatory response. Low concentrations of intracellular K+ are associated with the specific oligomerization and activation of the NLRP3 inflammasome, a type of inflammasome involved in sterile inflammation. Subsequent to NLRP3 oligomerization, ASC protein binds and form oligomeric filaments culminating in large protein complexes named ASC specks. ASC specks are also initiated from different inflammasome scaffolds, as AIM2, NLRC4 or Pyrin. ASC oligomers induce the recruitment of caspase-1 through interactions between their respective caspase activation and recruitment domains (CARD), and favoring its activation. So far ASC oligomerization and caspase-1 activation are considered as a K+-independent process. Here we found that ASC oligomers change their structure upon low intracellular K+ independently of NLRP3 and allow the ASCCARD domain to be more accessible for the recruitment of pro-caspase-1CARD domain. Therefore, conditions that decrease intracellular K+ not only drive NLRP3 responses, but also enhance the recruitment of pro-caspase-1 by ASC specks formed by different inflammasomes, indicating that intracellular K+ homeostasis is a key regulatory step for inflammasome regulation.

immunology↗