Although mutant forms of the gene encoding surfactant protein C (SFTPC) have been linked to interstitial lung disease, the mechanisms by which the most common of these mutations, SFTPCI73T, results in lung fibrosis are uncertain. In this issue of the JCI, Nureki et al. developed a knockin mouse model and showed that SFTPCI73T is expressed by alveolar type II (AT2) epithelial cells in the lungs. These mice developed an age-related fibrotic phenotype when the mutant allele was expressed at low levels and acute lung inflammation/injury followed by lung fibrosis when mutant SFTPCI73T expression was enhanced. This work provides important information regarding the impact of AT2 cell dysfunction on fibrotic remodeling in the lungs.
Timothy S. Blackwell
RBCs are the most abundant circulating cells in humans and typically comprise 35% to 45% of the blood volume (hematocrit). Anemia is associated with an increase in bleeding, and epidemiological studies have shown an association between an elevated hematocrit and thrombosis. RBCs may contribute to hemostasis and thrombosis via mechanisms that include platelet margination leading to an increase in the near-wall platelet concentration, blood viscosity, thrombin generation, and platelet activation. In this issue of the JCI, Klatt et al. report that binding of the Fas ligand FasL on the surface of platelets to its cognate receptor FasR on the surface of RBCs increases thrombin generation in vitro and thrombosis in mouse models. This represents a new mechanism by which RBCs contribute to thrombosis.
Under normal conditions, there is a paucity of neutrophils within the intestinal mucosa; however, these innate immune cells rapidly infiltrate the mucosa in response to infection and are critical for pathogen control. Unfortunately, these cells can cause extensive damage to the intestine if the initial inflammatory influx is not resolved. Factors that promote resolution of inflammation are of great interest, as they have therapeutic potential for limiting uncontrolled inflammatory damage. In this issue of the JCI, Szabady et al. demonstrate that the multidrug resistance transporter P-glycoprotein (P-gp) secretes endocannabinoids into the intestinal lumen that counteract the proinflammatory actions of the eicosanoid hepoxilin A3, which is secreted into the lumen by the efflux pump MRP2 and serves as a potent neutrophil chemoattractant. Moreover, the antiinflammatory actions of P-gp–secreted endocannabinoids were mediated by peripheral cannabinoid receptor CB2 on neutrophils. Together, the results of this study identify an important mechanism by which endogenous endocannabinoids facilitate the resolution of inflammation; this mechanism has potential to be therapeutically exploited.
Andrew S. Neish
Red blood cells (RBCs) influence rheology, and release ADP, ATP, and nitric oxide, suggesting a role for RBCs in hemostasis and thrombosis. Here, we provide evidence for a significant contribution of RBCs to thrombus formation. Anemic mice showed enhanced occlusion times upon injury of the carotid artery. A small population of RBCs was located to platelet thrombi and enhanced platelet activation by a direct cell contact via the FasL/FasR (CD95) pathway known to induce apoptosis. Activation of platelets in the presence of RBCs led to platelet FasL exposure that activated FasR on RBCs responsible for externalization of phosphatidylserine (PS) on the RBC membrane. Inhibition or genetic deletion of either FasL or FasR resulted in reduced PS exposure of RBCs and platelets, decreased thrombin generation, and reduced thrombus formation in vitro and protection against arterial thrombosis in vivo. Direct cell contacts between platelets and RBCs via FasL/FasR were shown after ligation of the inferior vena cava (IVC) and in surgical specimens of patients after thrombectomy. In a flow restriction model of the IVC, reduced thrombus formation was observed in FasL–/– mice. Taken together, our data reveal a significant contribution of RBCs to thrombosis by the FasL/FasR pathway.
Christoph Klatt, Irena Krüger, Saskia Zey, Kim-Jürgen Krott, Martina Spelleken, Nina Sarah Gowert, Alexander Oberhuber, Lena Pfaff, Wiebke Lückstädt, Kerstin Jurk, Martin Schaller, Hadi Al-Hasani, Jürgen Schrader, Steffen Massberg, Konstantin Stark, Hubert Schelzig, Malte Kelm, Margitta Elvers
Impaired lymphangiogenesis is a complication of chronic complex diseases, including diabetes. VEGF-C/VEGFR3 signaling promotes lymphangiogenesis, but how this pathway is affected in diabetes remains poorly understood. We previously demonstrated that loss of epsins 1 and 2 in lymphatic endothelial cells (LECs) prevented VEGF-C–induced VEGFR3 from endocytosis and degradation. Here, we report that diabetes attenuated VEGF-C–induced lymphangiogenesis in corneal micropocket and Matrigel plug assays in WT mice but not in mice with inducible lymphatic-specific deficiency of epsins 1 and 2 (LEC-iDKO). Consistently, LECs isolated from diabetic LEC-iDKO mice elevated in vitro proliferation, migration, and tube formation in response to VEGF-C over diabetic WT mice. Mechanistically, ROS produced in diabetes induced c-Src–dependent but VEGF-C–independent VEGFR3 phosphorylation, and upregulated epsins through the activation of transcription factor AP-1. Augmented epsins bound to and promoted degradation of newly synthesized VEGFR3 in the Golgi, resulting in reduced availability of VEGFR3 at the cell surface. Preclinically, the loss of lymphatic-specific epsins alleviated insufficient lymphangiogenesis and accelerated the resolution of tail edema in diabetic mice. Collectively, our studies indicate that inhibiting expression of epsins in diabetes protects VEGFR3 against degradation and ameliorates diabetes-triggered inhibition of lymphangiogenesis, thereby providing a novel potential therapeutic strategy to treat diabetic complications.
Hao Wu, H.N. Ashiqur Rahman, Yunzhou Dong, Xiaolei Liu, Yang Lee, Aiyun Wen, Kim H.T. To, Li Xiao, Amy E. Birsner, Lauren Bazinet, Scott Wong, Kai Song, Megan L. Brophy, M. Riaj Mahamud, Baojun Chang, Xiaofeng Cai, Satish Pasula, Sukyoung Kwak, Wenxia Yang, Joyce Bischoff, Jian Xu, Diane R. Bielenberg, J. Brandon Dixon, Robert J. D’Amato, R. Sathish Srinivasan, Hong Chen
DNA-damaging chemotherapy and radiation therapy are integrated into the treatment paradigm of the majority of cancer patients. Recently, immunotherapy that targets the immunosuppressive interaction between programmed death 1 (PD-1) and its ligand PD-L1 has been approved for malignancies including non–small cell lung cancer, melanoma, and head and neck squamous cell carcinoma. ATR is a DNA damage–signaling kinase activated at damaged replication forks, and ATR kinase inhibitors potentiate the cytotoxicity of DNA-damaging chemotherapies. We show here that the ATR kinase inhibitor AZD6738 combines with conformal radiation therapy to attenuate radiation-induced CD8+ T cell exhaustion and potentiate CD8+ T cell activity in mouse models of Kras-mutant cancer. Mechanistically, AZD6738 blocks radiation-induced PD-L1 upregulation on tumor cells and dramatically decreases the number of tumor-infiltrating Tregs. Remarkably, AZD6738 combines with conformal radiation therapy to generate immunologic memory in complete responder mice. Our work raises the possibility that a single pharmacologic agent may enhance the cytotoxic effects of radiation while concurrently potentiating radiation-induced antitumor immune responses.
Frank P. Vendetti, Pooja Karukonda, David A. Clump, Troy Teo, Ronald Lalonde, Katriana Nugent, Matthew Ballew, Brian F. Kiesel, Jan H. Beumer, Saumendra N. Sarkar, Thomas P. Conrads, Mark J. O’Connor, Robert L. Ferris, Phuoc T. Tran, Greg M. Delgoffe, Christopher J. Bakkenist
Neutrophil influx into the intestinal lumen is a critical response to infectious agents, but is also associated with severe intestinal damage observed in idiopathic inflammatory bowel disease. The chemoattractant hepoxilin A3, an eicosanoid secreted from intestinal epithelial cells by the apically restricted efflux pump multidrug resistance protein 2 (MRP2), mediates this neutrophil influx. Information about a possible counterbalance pathway that could signal the lack of or resolution of an apical inflammatory signal, however, has yet to be described. We now report a system with such hallmarks. Specifically, we identify endocannabinoids as the first known endogenous substrates of the apically restricted multidrug resistance transporter P-glycoprotein (P-gp) and reveal a mechanism, which we believe is novel, for endocannabinoid secretion into the intestinal lumen. Knockdown or inhibition of P-gp reduced luminal secretion levels of N-acyl ethanolamine–type endocannabinoids, which correlated with increased neutrophil transmigration in vitro and in vivo. Additionally, loss of CB2, the peripheral cannabinoid receptor, led to increased pathology and neutrophil influx in models of acute intestinal inflammation. These results define a key role for epithelial cells in balancing the constitutive secretion of antiinflammatory lipids with the stimulated secretion of proinflammatory lipids via surface efflux pumps in order to control neutrophil infiltration into the intestinal lumen and maintain homeostasis in the healthy intestine.
Rose L. Szabady, Christopher Louissaint, Anneke Lubben, Bailu Xie, Shaun Reeksting, Christine Tuohy, Zachary Demma, Sage E. Foley, Christina S. Faherty, Alejandro Llanos-Chea, Andrew J. Olive, Randall J. Mrsny, Beth A. McCormick
Controlling graft-versus-host disease (GVHD) remains a major unmet need in stem cell transplantation, and new, targeted therapies are being actively developed. CD28-CD80/86 costimulation blockade represents a promising strategy, but targeting CD80/CD86 with CTLA4-Ig may be associated with undesired blockade of coinhibitory pathways. In contrast, targeted blockade of CD28 exclusively inhibits T cell costimulation and may more potently prevent GVHD. Here, we investigated FR104, an antagonistic CD28-specific pegylated-Fab′, in the nonhuman primate (NHP) GVHD model and completed a multiparameter interrogation comparing it with CTLA4-Ig, with and without sirolimus, including clinical, histopathologic, flow cytometric, and transcriptomic analyses. We document that FR104 monoprophylaxis and combined prophylaxis with FR104/sirolimus led to enhanced control of effector T cell proliferation and activation compared with the use of CTLA4-Ig or CTLA4-Ig/sirolimus. Importantly, FR104/sirolimus did not lead to a beneficial impact on Treg reconstitution or homeostasis, consistent with control of conventional T cell activation and IL-2 production needed to support Tregs. While FR104/sirolimus had a salutary effect on GVHD-free survival, overall survival was not improved, due to death in the absence of GVHD in several FR104/sirolimus recipients in the setting of sepsis and a paralyzed INF-γ response. These results therefore suggest that effectively deploying CD28 in the clinic will require close scrutiny of both the benefits and risks of extensively abrogating conventional T cell activation after transplant.
Benjamin K. Watkins, Victor Tkachev, Scott N. Furlan, Daniel J. Hunt, Kayla Betz, Alison Yu, Melanie Brown, Nicolas Poirier, Hengqi Betty Zheng, Agne Taraseviciute, Lucrezia Colonna, Caroline Mary, Gilles Blancho, Jean-Paul Soulillou, Angela Panoskaltsis-Mortari, Prachi Sharma, Anapatricia Garcia, Elizabeth Strobert, Kelly Hamby, Aneesah Garrett, Taylor Deane, Bruce R. Blazar, Bernard Vanhove, Leslie S. Kean
The t-SNARE protein SNAP23 conventionally functions as a component of the cellular machinery required for intracellular transport vesicle fusion with target membranes and has been implicated in the regulation of fasting glucose levels, BMI, and type 2 diabetes. Surprisingly, we observed that adipocyte-specific KO of SNAP23 in mice resulted in a temporal development of severe generalized lipodystrophy associated with adipose tissue inflammation, insulin resistance, hyperglycemia, liver steatosis, and early death. This resulted from adipocyte cell death associated with an inhibition of macroautophagy and lysosomal degradation of the proapoptotic regulator BAX, with increased BAX activation. BAX colocalized with LC3-positive autophagic vacuoles and was increased upon treatment with lysosome inhibitors. Moreover, BAX deficiency suppressed the lipodystrophic phenotype in the adipocyte-specific SNAP23-KO mice and prevented cell death. In addition, ATG9 deficiency phenocopied SNAP23 deficiency, whereas ATG7 deficiency had no effect on BAX protein levels, BAX activation, or apoptotic cell death. These data demonstrate a role for SNAP23 in the control of macroautophagy and programmed cell death through an ATG9-dependent, but ATG7-independent, pathway regulating BAX protein levels and BAX activation.
Daorong Feng, Dulguun Amgalan, Rajat Singh, Jianwen Wei, Jennifer Wen, Tszki Peter Wei, Timothy E. McGraw, Richard N. Kitsis, Jeffrey E. Pessin
Cancer cell dependence on activated oncogenes is therapeutically targeted, but acquired resistance is virtually unavoidable. Here we show that the treatment of addicted melanoma cells with BRAF inhibitors, and of breast cancer cells with HER2-targeted drugs, led to an adaptive rise in neuropilin-1 (NRP1) expression, which is crucial for the onset of acquired resistance to therapy. Moreover, NRP1 levels dictated the efficacy of MET oncogene inhibitors in addicted stomach and lung carcinoma cells. Mechanistically, NRP1 induced a JNK-dependent signaling cascade leading to the upregulation of alternative effector kinases EGFR or IGF1R, which in turn sustained cancer cell growth and mediated acquired resistance to BRAF, HER2, or MET inhibitors. Notably, the combination with NRP1-interfering molecules improved the efficacy of oncogene-targeted drugs and prevented or even reversed the onset of resistance in cancer cells and tumor models. Our study provides the rationale for targeting the NRP1-dependent upregulation of tyrosine kinases, which are responsible for loss of responsiveness to oncogene-targeted therapies.
Sabrina Rizzolio, Gabriella Cagnoni, Chiara Battistini, Stefano Bonelli, Claudio Isella, Jo A. Van Ginderachter, René Bernards, Federica Di Nicolantonio, Silvia Giordano, Luca Tamagnone
Epithelial cell dysfunction is postulated as an important component in the pathogenesis of idiopathic pulmonary fibrosis (IPF). Mutations in the surfactant protein C (SP-C) gene (SFTPC), an alveolar type II (AT2) cell–restricted protein, have been found in sporadic and familial IPF. To causally link these events, we developed a knockin mouse model capable of regulated expression of an IPF-associated isoleucine-to-threonine substitution at codon 73 (I73T) in Sftpc (SP-CI73T). Tamoxifen-treated SP-CI73T cohorts developed rapid increases in SftpcI73T mRNA and misprocessed proSP-CI73T protein accompanied by increased early mortality (days 7–14). This acute phase was marked by diffuse parenchymal lung injury, tissue infiltration by monocytes, polycellular alveolitis, and elevations in bronchoalveolar lavage and AT2 mRNA content of select inflammatory cytokines. Resolution of alveolitis (2–4 weeks), commensurate with a rise in TGF-β1, was followed by aberrant remodeling marked by collagen deposition, AT2 cell hyperplasia, α–smooth muscle actin–positive (α-SMA–positive) cells, and restrictive lung physiology. The translational relevance of the model was supported by detection of multiple IPF biomarkers previously reported in human cohorts. These data provide proof of principle that mutant SP-C expression in vivo causes spontaneous lung fibrosis, strengthening the role of AT2 cell dysfunction as a key upstream driver of IPF pathogenesis.
Shin-Ichi Nureki, Yaniv Tomer, Alessandro Venosa, Jeremy Katzen, Scott J. Russo, Sarita Jamil, Matthew Barrett, Vivian Nguyen, Meghan Kopp, Surafel Mulugeta, Michael F. Beers
Regulatory T-cells (Treg) are critical for maintaining immune homeostasis. However, current Treg immunotherapies do not optimally treat inflammatory diseases in patients. Understanding the cellular processes that control Treg function may allow for the augmentation of therapeutic efficacy. In contrast to activated conventional T-cells, where protein kinase C-θ (PKC-θ) localizes to the contact-point between T-cells and antigen-presenting cells, in human and mouse Treg, PKC-θ localizes to the opposite end of the cell in the distal pole complex (DPC). Here, using a phosphoproteomic screen, we identified the intermediate filament vimentin as a PKC-θ phospho-target and show that vimentin forms a DPC superstructure on which PKC-θ accumulates. Treatment of mouse Treg with either a clinically relevant PKC-θ inhibitor or vimentin siRNA disrupted vimentin and enhanced Treg metabolic and suppressive activity. Moreover, vimentin-disrupted mouse Treg were significantly better than controls in suppressing alloreactive T-cell priming in graft-versus-host disease, and graft-versus-host disease lethality, using a complete MHC mismatch mouse model of acute graft-versus-host disease (C57BL/6 donor in to BALB/c host). Interestingly, vimentin disruption augmented suppressor function of PKC-θ-deficient mouse Treg. This suggests that enhanced Treg activity after PKC-θ inhibition is secondary to effects on vimentin, not just PKC-θ kinase activity inhibition. Our data demonstrated that vimentin is a key metabolic and functional controller of Treg activity, and provide proof-of-principle that disrupting vimentin is a feasible, translationally relevant method to enhance Treg potency.
Cameron McDonald-Hyman, James T. Muller, Michael Loschi, Govindarajan Thangavelu, Asim Saha, Sudha Kumari, Dawn K. Reichenbach, Michelle J. Smith, Guoan Zhang, Brent H. Koehn, Jiqiang Lin, Jason S. Mitchell, Brian T. Fife, Angela Panoskaltsis-Mortari, Colby J. Feser, Andrew Kemal Kirchmeier, Mark J. Osborn, Keli L. Hippen, Ameeta Kelekar, Jonathan S. Serody, Laurence A. Turka, David H. Munn, Hongbo Chi, Thomas A. Neubert, Michael L. Dustin, Bruce R. Blazar
Previous findings showed that in mice, complete knockout of activity-dependent neuroprotective protein (ADNP) abolishes brain formation, while haploinsufficiency (Adnp+/–) causes cognitive impairments. We hypothesized that mutations in ADNP lead to a developmental/autistic syndrome in children. Indeed, recent phenotypic characterization of children harboring ADNP mutations (ADNP syndrome children) revealed global developmental delays and intellectual disabilities, including speech and motor dysfunctions. Mechanistically, ADNP includes a SIP motif embedded in the ADNP-derived snippet, drug candidate NAP (NAPVSIPQ also known as CP201), which binds to microtubule end binding protein 3, essential for dendritic spine formation. Here, we established a unique neuronal membrane tagged green fluorescent protein expressing Adnp+/– mouse line allowing in vivo synaptic pathology quantification. We discovered that Adnp deficiency reduced dendritic spine density and altered synaptic gene expression, both of which were partly ameliorated by NAP treatment. Adnp+/– mice further exhibited global developmental delays, vocalization impediments, gait/motor dysfunctions and social/object memory impairments, all partially reversed by daily NAP administration (systemic/nasal). In conclusion, we now connected ADNP-related synaptic pathology to developmental/behavioral outcomes, establishing NAP in vivo target engagement and identifying potential biomarkers. Together, these studies pave the path toward clinical development of NAP (CP201) in the ADNP syndrome.
Gal Hacohen-Kleiman, Shlomo Sragovich, Gidon Karmon, Andy Y. L. Gao, Iris Grigg, Metsada Pasmanik-Chor, Albert Le, Vlasta Korenková, R. Anne McKinney, Illana Gozes
Graft-versus-host disease (GVHD) in the gastrointestinal (GI) tract remains the major cause of morbidity and non-relapse mortality after bone marrow transplantation (BMT). The Paneth cell protein, regenerating islet-derived 3-alpha (REG3α), is a biomarker specific for GI GVHD. REG3α serum levels rose in the systematic circulation as GVHD progressively destroyed Paneth cells and reduced GI epithelial barrier function. Paradoxically, GVHD suppressed intestinal REG3γ (the mouse homologue of human REG3α), and the absence of REG3γ in BMT recipients intensified GVHD but did not change the composition of the microbiome. IL-22 administration restored REG3γ production and prevented apoptosis of both intestinal stem cells (ISCs) and Paneth cells, but this protection was completely abrogated in Reg3g−/− mice. In vitro, addition of REG3α reduced the apoptosis of colonic cell lines. Strategies that increase intestinal REG3α/γ to promote crypt regeneration may offer a novel, non-immunosuppressive approach for GVHD and perhaps for other diseases involving the ISC niche such as inflammatory bowel disease.
Dongchang Zhao, Yeung-Hyen Kim, Seihwan Jeong, Joel K. Greenson, Mohammed S. Chaudhry, Matthias Hoepting, Erik R. Anderson, Marcel R.M. van den Brink, Jonathan U. Peled, Antonio L.C. Gomes, Ann E. Slingerland, Michael J. Donovan, Andrew C. Harris, John E. Levine, Umut Özbek, Lora V. Hooper, Thaddeus S. Stappenbeck, Aaron M. Ver Heul, Ta-Chiang Liu, Pavan Reddy, James L.M. Ferrara
B cells are increasingly recognised to play an important role in the ongoing control of hepatitis B virus (HBV). The development of antibodies against the viral surface antigen (HBsAg) constitutes the hallmark of resolution of acute infection and is a therapeutic goal for functional cure of chronic HBV (CHB). We characterised B cells directly ex vivo from the blood and liver of patients with CHB to investigate constraints on their antiviral potential. Unexpectedly, we found that HBsAg-specific B cells persisted in the blood and liver of many patients with CHB and were enriched for T-bet, a signature of antiviral potential in B cells. However purified, differentiated HBsAg-specific B cells from patients with CHB had defective antibody production, consistent with undetectable anti-HBs antibodies in vivo. HBsAg-specific and global B cells had an accumulation of CD21–CD27– atypical memory B cells (atMBC) with high expression of inhibitory receptors including PD-1. These atMBC demonstrated altered signalling, homing, differentiation into antibody-producing cells, survival and antiviral/pro-inflammatory cytokine production, that could be partially rescued by PD-1 blockade. Analysis of B cells within healthy and HBV-infected livers implicated the combination of this tolerogenic niche and HBV infection in driving PD-1hiatMBC and impairing B cell immunity.
Alice R. Burton, Laura J. Pallett, Laura E. McCoy, Kornelija Suveizdyte, Oliver E. Amin, Leo Swadling, Elena Alberts, Brian R. Davidson, Patrick T.F. Kennedy, Upkar S. Gill, Claudia Mauri, Paul A. Blair, Nadege Pelletier, Mala K. Maini
Chronic HBV (CHB) infection suppresses virus-specific T cells, but its impact on humoral immunity has been poorly analyzed. Here, we developed a dual staining method, which utilizes HBsAg labelled with fluorochromes as “baits”, for specific ex vivo detection of HBsAg-specific B cells and analysis of their quantity, function and phenotype. We studied healthy vaccinated subjects (n=18) and patients with resolved (n=21), acute (n=11) or chronic (n=96) HBV infection and observed that frequencies of circulating HBsAg-specific B cells are independent of the HBV infection status. In contrast, serum HBsAg presence affects function and phenotype of HBsAg-specific B cells that were unable to mature in vitro into antibody-secreting cells and displayed an increased expression of markers linked to hyperactivation (CD21low) and exhaustion (PD-1). Importantly, B cell alterations were not limited to HBsAg-specific B cells but affected the global B cell population. HBsAg-specific B cell maturation could be partially restored by a method involving the combination of IL-2, IL-21 and CD40L-expressing feeder cells, and further boosted by addition of anti-PD-1 antibodies.In conclusion, HBV infection has a marked impact on global and HBV-specific humoral immunity, yet HBsAg-specific B cells are amenable to a partial rescue by B cell maturing cytokines and PD-1 blockade.
Loghman Salimzadeh, Nina Le Bert, Charles-A. Dutertre, Upkar S. Gill, Evan W. Newell, Christian Frey, Magdeleine Hung, Nikolai Novikov, Simon Fletcher, Patrick T.F. Kennedy, Antonio Bertoletti
In this issue of the JCI, Macrae et al. report that fibrin forms films on the air-exposed surface of blood clots that provide acute protection from pathogens following cutaneous injury. The cover image, captured by SEM, reveals a fibrin film at the air-exposed surface of a blood clot. A perforation in the film exposes the RBCs and polymerized fiber strands contained within.
JCI This Month is a digest of the research, reviews, and other features published each month.
Infection and injury induce self-limited inflammatory responses that mount a defense against pathogens and initiate activities that expedite recovery. However, the benefits of inflammation recede when these responses fail to resolve in a timely manner. This series features a family of specialized lipid mediators that regulate the resolution of inflammation. The reviews, curated by Charles Serhan, highlight the wide-ranging involvement of these bioactive lipids in health and disease. Work by Serhan and others has revealed that the resolvin, protectin, and maresin families of pro-resolving mediators act as immunoresolvents and represent promising alternatives to immunosuppressant and anti-inflammatory therapies. Other lipid mediators, including leukotrienes, ceramides, and sphingolipids have roles in cancer, cardiovascular disease, and aging. Our evolving understanding of lipid mediators in regulating inflammation and disease pathogenesis presents promising opportunities for new therapeutic strategies.