CXCR1/2 dual-inhibitor ladarixin reduces tumour burden and promotes immunotherapy response in pancreatic cancer.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy with few therapeutic options available. Despite immunotherapy has revolutionised cancer treatment, the results obtained in PDAC are still disappointing. Emerging evidence suggests that chemokines/CXCRs-axis plays a pivotal role in immune tumour microenvironment modulation, which may influence immunotherapy responsiveness. Here, we evaluated the effectiveness of CXCR1/2 inhibitor ladarixin, alone or in combination with anti-PD-1, against immunosuppression in PDAC. METHODS: A set of preclinical models was obtained by engrafting mouse PDAC-derived cells into syngeneic immune-competent mice, as well as by orthotopically transplanting patient-derived PDAC tumour into human immune-system-reconstituted (HIR) mice (HuCD34-NSG-mice). Tumour-bearing mice were randomly assigned to receive vehicles, ladarixin, anti-PD-1 or drugs combination. RESULTS: CXCR1/2 inhibition by ladarixin reverted in vitro tumour-mediated M2 macrophages polarisation and migration. Ladarixin as single agent reduced tumour burden in cancer-derived graft (CDG) models with high-immunogenic potential and increased the efficacy of ICI in non-immunogenic CDG-resistant models. In a HIR mouse model bearing the immunogenic subtype of human PDAC, ladarixin showed high efficacy increasing the antitumor effect of anti-PD-1. CONCLUSION: Ladarixin in combination with anti-PD-1 might represent an extremely effective approach for the treatment of immunotherapy refractory PDAC, allowing pro-tumoral to immune-permissive microenvironment conversion.

The therapeutic potential of an allosteric non-competitive CXCR1/2 antagonist for diabetic nephropathy.

AIMS: Diabetic nephropathy is a major consequence of inflammation developing in type 1 diabetes, with interleukin-8 (IL-8)-CXCR1/2 axis playing a key role in kidney disease progression. In this study, we investigated the therapeutic potential of a CXCR1/2 non-competitive allosteric antagonist (Ladarixin) in preventing high glucose-mediated injury in human podocytes and epithelial cells differentiated from renal stem/progenitor cells (RSC) cultured as nephrospheres. MATERIALS AND METHODS: We used human RSCs cultured as nephrospheres through a sphere-forming functional assay to investigate hyperglycemia-mediated effects on IL-8 signalling in human podocytes and tubular epithelial cells. RESULTS: High glucose impairs RSC self-renewal, induces an increase in IL-8 transcript expression and protein secretion and induces DNA damage in RSC-differentiated podocytes, while exerting no effect on RSC-differentiated epithelial cells. Accordingly, the supernatant from epithelial cells or podocytes cultured in high glucose was able to differentially activate leucocyte-mediated secretion of pro-inflammatory cytokines, suggesting that the crosstalk between immune and non-immune cells may be involved in disease progression in vivo. CONCLUSIONS: Treatment with Ladarixin during RSC differentiation prevented high glucose-mediated effects on podocytes and modulated either podocyte or epithelial cell-dependent leucocyte secretion of pro-inflammatory cytokines, suggesting CXCR1/2 antagonists as possible pharmacological approaches for the treatment of diabetic nephropathy.

Thyroid Hormone Signalling Alteration in Diabetic Nephropathy and Cardiomyopathy: a "Switch" to the Foetal Gene Programme.

PURPOSE OF THE REVIEW: In this study, we will analyse how diabetes induces the reactivation of organs' developmental programmes and growth, discuss how thyroid hormone (TH) signalling orchestrates these processes, and suggest novel strategies for exploiting TH-mediated reparative and regenerative properties. RECENT FINDINGS: Diabetes is a global pandemic that poses an enormous threat to human health. The kidney and the heart are among the organs that are the most severely damaged by diabetes over time. They undergo profound metabolic, structural, and functional changes that may be due (at least partially) to a recapitulation of their early developmental programmes. There is growing evidence to suggest that this foetal reprogramming is controlled by the TH/TH receptor alpha 1 (TRα1) axis. We introduce the hypothesis that in diabetes-and probably in other diseases-TH signalling acts in an antagonistic manner: it recapitulates a foetal profile that is necessary to coordinate metabolic and structural adaptations to sustain energy preservation and growth, but in the long term the persistent changes in these pathways are detrimental.

The Role of Angiotensin II in Parietal Epithelial Cell Proliferation and Crescent Formation in Glomerular Diseases.

Crescentic glomerulonephritis (GN) is a devastating disease with rapidly progressive deterioration in kidney function, which, histologically, manifests as crescent formation in most glomeruli. We previously found that crescents derive from the aberrant proliferation and migration of parietal epithelial cells (PECs)/progenitor cells, and that the angiotensin (ang) II/ang II type-1 (AT1) receptor pathway may participate, together with the stromal cell-derived factor-1 (SDF-1)/C-X-C chemokine receptor 4 axis, in the development of those lesions. Herein, we elucidated sequential events and cellular and molecular interactions occurring during crescentic lesion onset and evolution. By analyzing kidney biopsy specimens of patients with extracapillary GN, divided according to the grade of glomerular lesions, we found that the accumulation of macrophages expressing matrix metalloproteinase-12 started manifesting in glomeruli affected by early-stage lesions, whereas AT1 receptor expression could not be detected. In glomeruli with advanced lesions, AT1 receptor expression increased markedly, and the up-regulation of SDF-1, and its receptor C-X-C chemokine receptor 7, was documented on podocytes and PECs, respectively. In vitro studies were instrumental to demonstrating the role of ang II in inducing podocyte SDF-1 production, which ultimately activates PECs. The present findings support the possibility that angiotensin-converting enzyme inhibitor treatment might limit PEC activation and reduce the frequency and extension of crescents in extracapillary GN.

B7-1 Is Not Induced in Podocytes of Human and Experimental Diabetic Nephropathy.

The incidence of progressive kidney disease associated with diabetes continues to rise worldwide. Current standard therapy with angiotensin-converting enzyme inhibitors and/or angiotensin receptor blockers achieves only partial renoprotection, increasing the need for novel therapeutic approaches. Previous studies described B7-1 induction in podocytes of patients with proteinuria, including those with FSGS and type 2 diabetic nephropathy (DN). These findings sparked great excitement in the renal community, implying that abatacept, a costimulatory inhibitor that targets B7-1, could be a novel therapy for diabetic renal disease. Given previous concerns over the value of B7-1 immunostaining and the efficacy of abatacept in patients with recurrent FSGS after renal transplantation, we investigated B7-1 expression in human and experimental DN before embarking on clinical studies of the use of B7-1 targeting strategies to treat proteinuria in DN. Immunohistochemical analysis of kidney specimens using different antibodies revealed that B7-1 is not induced in podocytes of patients with DN, independent of disease stage, or BTBR ob/obmice, a model of type 2 diabetes. These results do not support the use of abatacept as a therapeutic strategy for targeting podocyte B7-1 for the prevention or treatment of DN.

Functional Human Podocytes Generated in Organoids from Amniotic Fluid Stem Cells.

Generating kidney organoids using human stem cells could offer promising prospects for research and therapeutic purposes. However, no cell-based strategy has generated nephrons displaying an intact three-dimensional epithelial filtering barrier. Here, we generated organoids using murine embryonic kidney cells, and documented that these tissues recapitulated the complex three-dimensional filtering structure of glomerular slits in vivo and accomplished selective glomerular filtration and tubular reabsorption. Exploiting this technology, we mixed human amniotic fluid stem cells with mouse embryonic kidney cells to establish three-dimensional chimeric organoids that engrafted in vivo and grew to form vascularized glomeruli and tubular structures. Human cells contributed to the formation of glomerular structures, differentiated into podocytes with slit diaphragms, and internalized exogenously infused BSA, thus attaining in vivo degrees of specialization and function unprecedented for donor stem cells. In conclusion, human amniotic fluid stem cell chimeric organoids may offer new paths for studying renal development and human podocyte disease, and for facilitating drug discovery and translational research.

Any value of podocyte B7-1 as a biomarker in human MCD and FSGS?

Minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) are the most common causes of nephrotic syndrome in children and in young adults. Relapsing MCD carries the risk of severe complications and prolonged immunosuppression, whereas FSGS remains largely untreatable and urgently needs more effective treatments. Recently, induction of B7-1 (CD80), an immune-related protein expressed by antigen-presenting cells, was observed in podocytes of MCD and FSGS patients, suggesting that B7-1 plays a role in the pathogenesis of these diseases, and hence that abatacept, a B7-1 inhibitor, could be a possible treatment. Since previous studies raised serious concerns regarding the reliability of immunohistochemical assays for B7-1 detection and the efficacy of B7-1 inhibitory treatment, we investigated B7-1 podocyte expression in MCD and FSGS patients. Using different primary antibodies and immunohistochemical assays, no significant upregulation of podocyte B7-1 was detected in patients' biopsies compared with controls. To further confirm our findings, we analyzed mice with adriamycin-induced nephropathy, a model of human FSGS, and mice injected with LPS as additional control. Podocyte B7-1 was not observed in mice injected with adriamycin or LPS either. In conclusion, since B7-1 is not induced in podocyte of MCD and FSGS patients, the antiproteinuric action of abatacept, if confirmed, may not be the result of an effect on podocyte B7-1.

Inhibiting angiotensin-converting enzyme promotes renal repair by modulating progenitor cell activation.

Independently of the initial insult, activation and accumulation of parietal progenitor cells within the Bowman's space is a peculiar feature of proliferative chronic kidney diseases. Clinical and experimental studies demonstrated that, in the presence of extensive renal damage, progenitor cells proliferate excessively in the failed attempt to replace the injured podocytes, contributing to the development of crescentic lesions. Inhibiting angiotensin-converting enzyme (ACE) halts crescent formation and promotes the restoration of normal glomerular architecture by limiting progenitor cell proliferation and migration towards the glomerular tuft. Among the mediators involved in the dysregulated response of renal precursors, the angiotensin II (ang II)/ang II type-1 (AT1) receptor/CXCR4 pathway have been demonstrated to be crucial in proliferative diseases. Understanding the mechanisms underlying the formation of crescentic lesions could be instrumental to developing new therapies, which can be more effective and more targeted to molecular mediators than the currently used cytotoxic agents.

ß-arrestin-1 drives endothelin-1-mediated podocyte activation and sustains renal injury.

Activation of endothelin-A receptor (ET(A)R) by endothelin-1 (ET-1) drives epithelial-to-mesenchymal transition in ovarian tumor cells through ß-arrestin signaling. Here, we investigated whether this pathogenetic pathway could affect podocyte phenotype in proliferative glomerular disorders. In cultured mouse podocytes, ET-1 caused loss of the podocyte differentiation marker synaptopodin and acquisition of the mesenchymal marker α-smooth muscle actin. ET-1 promoted podocyte migration via ET(A)R activation and increased ß-arrestin-1 expression. Activated ET(A)R recruited ß-arrestin-1 to form a trimeric complex with Src leading to epithelial growth factor receptor (EGFR) transactivation and ß-catenin phosphorylation, which promoted gene transcription of Snail. Increased Snail expression fostered ET-1-induced migration as confirmed by Snail knockdown experiments. Silencing of ß-arrestin-1 prevented podocyte phenotypic changes and motility and inhibited ET(A)R-driven signaling. In vitro findings were confirmed in doxorubicin (Adriamycin)-induced nephropathy. Mice receiving Adriamycin developed renal injury with loss of podocytes and hyperplastic lesion formation; ß-arrestin-1 expression increased in visceral podocytes and in podocytes entrapped in pseudo-crescents. Administration of the selective ET(A)R antagonist sitaxsentan prevented podocyte loss, formation of the hyperplastic lesions, and normalized expression of glomerular ß-arrestin-1 and Snail. Increased ß-arrestin-1 levels in podocytes retrieved from crescents of patients with proliferative glomerulopathies confirmed the translational relevance of these findings and suggest the therapeutic potential of ET(A)R antagonism for a group of diseases still needing a specific treatment.

Nature and mediators of parietal epithelial cell activation in glomerulonephritides of human and rat.

Bowman's capsule parietal epithelial cell activation occurs in several human proliferative glomerulonephritides. The cellular composition of the resulting hyperplastic lesions is controversial, although a population of CD133(+)CD24(+) progenitor cells has been proposed to be a major constituent. Mediator(s) involved in proliferation and migration of progenitor cells into the Bowman's space have been poorly explored. In a series of 36 renal biopsies of patients with proliferative and nonproliferative glomerulopathies, dysregulated CD133(+)CD24(+) progenitor cells of the Bowman's capsule invade the glomerular tuft exclusively in proliferative disorders. Up-regulation of the CXCR4 chemokine receptor on progenitor cells was accompanied by high expression of its ligand, SDF-1, in podocytes. Parietal epithelial cell proliferation might be sustained by increased expression of the angiotensin II (Ang II) type-1 (AT1) receptor. Similar changes of CXCR4, SDF-1, and AT1 receptor expression were found in Munich Wistar Frömter rats with proliferative glomerulonephritis. Moreover, an angiotensin-converting enzyme inhibitor normalized CXCR4 and AT1 receptor expression on progenitors concomitant with regression of crescentic lesions in a patient with crescentic glomerulonephritis. These results suggest that glomerular hyperplastic lesions derive from the proliferation and migration of renal progenitors in response to injured podocytes. The Ang II/AT1 receptor pathway may participate, together with SDF-1/CXCR4 axis, to the dysregulated response of renal precursors. Thus, targeting the Ang II/AT1 receptor/CXCR4 pathways may be beneficial in severe forms of glomerular proliferative disorders.

DHFR Inhibitors Display a Pleiotropic Anti-Viral Activity against SARS-CoV-2: Insights into the Mechanisms of Action.

During the COVID-19 pandemic, drug repurposing represented an effective strategy to obtain quick answers to medical emergencies. Based on previous data on methotrexate (MTX), we evaluated the anti-viral activity of several DHFR inhibitors in two cell lines. We observed that this class of compounds showed a significant influence on the virus-induced cytopathic effect (CPE) partly attributed to the intrinsic anti-metabolic activity of these drugs, but also to a specific anti-viral function. To elucidate the molecular mechanisms, we took advantage of our EXSCALATE platform for in-silico molecular modelling and further validated the influence of these inhibitors on nsp13 and viral entry. Interestingly, pralatrexate and trimetrexate showed superior effects in counteracting the viral infection compared to other DHFR inhibitors. Our results indicate that their higher activity is due to their polypharmacological and pleiotropic profile. These compounds can thus potentially give a clinical advantage in the management of SARS-CoV-2 infection in patients already treated with this class of drugs.

Adsorption of the rhNGF Protein on Polypropylene with Different Grades of Copolymerization.

The surface properties of drug containers should reduce the adsorption of the drug and avoid packaging surface/drug interactions, especially in the case of biologically-derived products. Here, we developed a multi-technique approach that combined Differential Scanning Calorimetry (DSC), Atomic Force Microscopy (AFM), Contact Angle (CA), Quartz Crystal Microbalance with Dissipation monitoring (QCM-D), and X-ray Photoemission Spectroscopy (XPS) to investigate the interactions of rhNGF on different pharma grade polymeric materials. Polypropylene (PP)/polyethylene (PE) copolymers and PP homopolymers, both as spin-coated films and injected molded samples, were evaluated for their degree of crystallinity and adsorption of protein. Our analyses showed that copolymers are characterized by a lower degree of crystallinity and lower roughness compared to PP homopolymers. In line with this, PP/PE copolymers also show higher contact angle values, indicating a lower surface wettability for the rhNGF solution on copolymers than PP homopolymers. Thus, we demonstrated that the chemical composition of the polymeric material and, in turn, its surface roughness determine the interaction with the protein and identified that copolymers may offer an advantage in terms of protein interaction/adsorption. The combined QCM-D and XPS data indicated that protein adsorption is a self-limiting process that passivates the surface after the deposition of roughly one molecular layer, preventing any further protein adsorption in the long term.

Combination Drug Therapy for the Management of Chronic Neuropathic Pain.

Chronic neuropathic pain (NP) is an increasingly prevalent disease and leading cause of disability which is challenging to treat. Several distinct classes of drugs are currently used for the treatment of chronic NP, but each drug targets only narrow components of the underlying pathophysiological mechanisms, bears limited efficacy, and comes with dose-limiting side effects. Multimodal therapies have been increasingly proposed as potential therapeutic approaches to target the multiple mechanisms underlying nociceptive transmission and modulation. However, while preclinical studies with combination therapies showed promise to improve efficacy over monotherapy, clinical trial data on their efficacy in specific populations are lacking and increased risk for adverse effects should be carefully considered. Drug-drug co-crystallization has emerged as an innovative pharmacological approach which can combine two or more different active pharmaceutical ingredients in a single crystal, optimizing pharmacokinetic and physicochemical characteristics of the native molecules, thus potentially capitalizing on the synergistic efficacy between classes of drugs while simplifying adherence and minimizing the risk of side effects by reducing the doses. In this work, we review the current pharmacological options for the treatment of chronic NP, focusing on combination therapies and their ongoing developing programs and highlighting the potential of co-crystals as novel approaches to chronic NP management.

Ketoprofen, lysine and gabapentin co-crystal magnifies synergistic efficacy and tolerability of the constituent drugs: Pre-clinical evidences towards an innovative therapeutic approach for neuroinflammatory pain.

Chronic pain is an enormous public health concern, and its treatment is still an unmet medical need. Starting from data highlighting the promising effects of some nonsteroidal anti-inflammatory drugs in combination with gabapentin in pain treatment, we sought to combine ketoprofen lysine salt (KLS) and gabapentin to obtain an effective multimodal therapeutic approach for chronic pain. Using relevant in vitro models, we first demonstrated that KLS and gabapentin have supra-additive effects in modulating key pathways in neuropathic pain and gastric mucosal damage. To leverage these supra-additive effects, we then chemically combined the two drugs via co-crystallization to yield a new compound, a ternary drug-drug co-crystal of ketoprofen, lysine and gabapentin (KLS-GABA co-crystal). Physicochemical, biodistribution and pharmacokinetic studies showed that within the co-crystal, ketoprofen reaches an increased gastrointestinal solubility and permeability, as well as a higher systemic exposure in vivo compared to KLS alone or in combination with gabapentin, while both the constituent drugs have increased central nervous system permeation. These unique characteristics led to striking, synergistic anti-nociceptive and anti-inflammatory effects of KLS-GABA co-crystal, as well as significantly reduced spinal neuroinflammation, in translational inflammatory and neuropathic pain rat models, suggesting that the synergistic therapeutic effects of the constituent drugs are further boosted by the co-crystallization. Notably, while strengthening the therapeutic effects of ketoprofen, KLS-GABA co-crystal showed remarkable gastrointestinal tolerability in both inflammatory and chronic neuropathic pain rat models. In conclusion, these results allow us to propose KLS-GABA co-crystal as a new drug candidate with high potential clinical benefit-to-risk ratio for chronic pain treatment.

Ketoprofen lysine salt has a better gastrointestinal and renal tolerability than ketoprofen acid: A comparative tolerability study in the Beagle dog.

Due to the widespread use of non-steroidal anti-inflammatory drugs (NSAIDs), the incidence of NSAID-associated adverse events has increased exponentially over the past decades. Ketoprofen (ketoprofen acid, KA) is a widely used NSAID and, like with other NSAIDs, its use can be associated with adverse effects that especially involve the gastrointestinal tract and the kidney. The salification of KA with L-lysine has led to the synthesis of ketoprofen lysine salt (KLS), which is characterized by higher solubility and a more rapid gastrointestinal absorption compared to KA. Previous studies have reported that KLS has also an increased gastric tolerance in vitro, and this is due to the inhibition of lipid peroxidation and reactive oxygen species scavenging effects of L-lysine. Here, we report in vivo tolerability/toxicity studies that were conducted prior seeking KLS marketing authorization, in which we compared KLS and KA safety profile, focusing in particular on the evaluation of the gastrointestinal and renal tolerability of the drugs administered orally to dogs. Our results demonstrate that KLS has an increased in vivo gastrointestinal tolerability compared to KA and show, for the first time, that KLS has also increased in vivo renal tolerability compared to KA, thus supporting the concept that L-lysine may counteract NSAID-induced oxidative stress-mediated gastrointestinal and renal injury.

The role of C5a-C5aR1 axis in bone pathophysiology: A mini-review.

Bone remodeling is a physiological, dynamic process that mainly depends on the functions of 2 cell types: osteoblasts and osteoclasts. Emerging evidence suggests that complement system is crucially involved in the regulation of functions of these cells, especially during inflammatory states. In this context, complement component 5a (C5a), a powerful pro-inflammatory anaphylatoxin that binds the receptor C5aR1, is known to regulate osteoclast formation and osteoblast inflammatory responses, and has thus been proposed as potential therapeutic target for the treatment of inflammatory bone diseases. In this review, we will analyze the role of C5a-C5aR1 axis in bone physiology and pathophysiology, describing its involvement in the pathogenesis of some of the most frequent inflammatory bone diseases such as rheumatoid arthritis, and also in osteoporosis and bone cancer and metastasis. Moreover, we will examine C5aR1-based pharmacological approaches that are available and have been tested so far for the treatment of these conditions. Given the growing interest of the scientific community on osteoimmunology, and the scarcity of data regarding the role of C5a-C5aR1 axis in bone pathophysiology, we will highlight the importance of this axis in mediating the interactions between skeletal and immune systems and its potential use as a therapeutic target.

The role of extracellular vesicles and interleukin-8 in regulating and mediating neutrophil-dependent cancer drug resistance.

Tumor drug resistance is a multifactorial and heterogenous condition that poses a serious burden in clinical oncology. Given the increasing incidence of resistant tumors, further understanding of the mechanisms that make tumor cells able to escape anticancer drug effects is pivotal for developing new effective treatments. Neutrophils constitute a considerable proportion of tumor infiltrated immune cells, and studies have linked elevated neutrophil counts with poor prognosis. Tumor-associated neutrophils (TANs) can acquire in fact immunoregulatory capabilities, thus regulating tumor progression and resistance, or response to therapy. In this review, we will describe TANs' actions in the tumor microenvironment, with emphasis on the analysis of the role of interleukin-8 (IL-8) and extracellular vesicles (EVs) as crucial modulators and mediators of TANs biology and function in tumors. We will then discuss the main mechanisms through which TANs can induce drug resistance, finally reporting emerging therapeutic approaches that target these mechanisms and can thus be potentially used to reduce or overcome neutrophil-mediated tumor drug resistance.

Inflammation-Independent Antinociceptive Effects of DF2755A, a CXCR1/2 Selective Inhibitor: A New Potential Therapeutic Treatment for Peripheral Neuropathy Associated to Non-Ulcerative Interstitial Cystitis/Bladder Pain Syndrome.

Interstitial cystitis (IC)/bladder pain syndrome (BPS) is a chronic bladder disease of unknown etiology characterized by urinary frequency and episodic and chronic pain. Analgesic treatments for IC/BPS are limited, especially for patients with non-Hunner (non-ulcerative) type IC who usually have poor overall outcomes. Here, we demonstrate that oral treatment with DF2755A, a potent and selective inhibitor of chemokine receptors CXCR1/2, can prevent and reverse peripheral neuropathy associated to non-Hunner IC/BPS by directly inhibiting chemokine-induced excitation of sensory neurons. We tested DF2755A antinociceptive effects in a cyclophosphamide (CYP)-induced non-ulcerative IC rat model characterized by severe peripheral neuropathy in the absence of bladder inflammatory infiltrate, urothelial hyperplasia, and hemorrhage. Treatment with DF2755A prevented the onset of peripheral neuropathy and reversed its development in CYP-induced IC rats, showing a strong and long-lasting anti-hyperalgesic effect. Ex vivo and in vitro studies showed that DF2755A treatment strongly inhibited the expression of CXCR2 agonists, CXCL1/KC, and CXCL5 and of transient receptor potential vanilloid 1 (TRPV1) compared to vehicle, suggesting that its effects can be due to the inhibition of the nociceptive signaling passing through the CXCL1/CXCR1-2 axis and TRPV1. In conclusion, our results highlight the key pathophysiological role played by the CXCL1/CXCR1-2 axis and TRPV1 in the onset and development of peripheral neuropathy in non-Hunner IC and propose DF2755A as a potential therapeutic approach for the treatment of not only inflammatory painful conditions but also neuropathic ones and in particular non-Hunner IC/BPS.

Paclitaxel binds and activates C5aR1: A new potential therapeutic target for the prevention of chemotherapy-induced peripheral neuropathy and hypersensitivity reactions.

Chemotherapy-induced peripheral neuropathy (CIPN) and hypersensitivity reactions (HSRs) are among the most frequent and impairing side effects of the antineoplastic agent paclitaxel. Here, we demonstrated that paclitaxel can bind and activate complement component 5a receptor 1 (C5aR1) and that this binding is crucial in the etiology of paclitaxel-induced CIPN and anaphylaxis. Starting from our previous data demonstrating the role of interleukin (IL)-8 in paclitaxel-induced neuronal toxicity, we searched for proteins that activate IL-8 expression and, by using the Exscalate platform for molecular docking simulations, we predicted the high affinity of C5aR1 with paclitaxel. By in vitro studies, we confirmed the specific and competitive nature of the C5aR1-paclitaxel binding and found that it triggers intracellularly the NFkB/P38 pathway and c-Fos. In F11 neuronal cells and rat dorsal root ganglia, C5aR1 inhibition protected from paclitaxel-induced neuropathological effects, while in paclitaxel-treated mice, the absence (knock-out mice) or the inhibition of C5aR1 significantly ameliorated CIPN symptoms-in terms of cold and mechanical allodynia-and reduced the chronic pathological state in the paw. Finally, we found that C5aR1 inhibition can counteract paclitaxel-induced anaphylactic cytokine release in macrophages in vitro, as well as the onset of HSRs in mice. Altogether these data identified C5aR1 as a key mediator and a new potential pharmacological target for the prevention and treatment of CIPN and HSRs induced by paclitaxel.