Proteasome inhibitor bortezomib suppresses nuclear factor-kappa B activation and ameliorates eye inflammation in experimental autoimmune uveitis

Phenotype-structured model of intra-clonal heterogeneity and drug resistance in multiple myeloma

Multiple myeloma (MM) is a genetically complex hematological cancer characterized by the abnormal proliferation of malignant plasma cells in the bone marrow. This disease progresses from a premalignant condition known as monoclonal gammopathy of unknown significance (MGUS) through sequential genetic alterations involving various genes. These genetic changes contribute to the uncontrolled growth of multiple clones of plasma cells. In this study, we present a phenotype-structured model that captures the intra-clonal heterogeneity and drug resistance in multiple myeloma (MM). The model accurately reproduces the branching evolutionary pattern observed in MM progression, aligning with a previously developed multiscale model. Numerical simulations reveal that higher mutation rates enhance tumor phenotype diversity, while access to growth factors accelerates tumor evolution and increases its final size. Interestingly, the model suggests that further increasing growth factor access primarily amplifies tumor size rather than altering clonal dynamics. Additionally, the model emphasizes that higher mutation frequencies and growth factor availability elevate the chances of drug resistance and relapse. It indicates that the timing of the treatment could trajectory of tumor evolution and clonal emergence in the case of branching evolutionary pattern. Given its low computational cost, our model is well-suited for quantitative studies on MM clonal heterogeneity and its interaction with chemotherapeutic treatments.

In vitro and in silico perspectives to explain anticancer activity of a novel syringic acid analog ((4-(1H-1, 3-benzodiazol-2-yl)-2, 6-dimethoxy phenol)) through apoptosis activation and NFkB inhibition in K562 leukemia cells

Syringic acid (SA) is an active carcinogenesis inhibitor; however, the low bioavailability and unstable functional groups hinder its activity. Here, a chemically synthesized novel SA analog (SA10) is evaluated for its anticancer activity using in-vitro and in-silico studies. K562 cell line study revealed that SA10 had shown a higher rate of inhibition (IC50 = 50.40 μg/mL) than its parental compound, SA (IC50 = 96.92 μg/mL), at 50 μM concentration. The inhibition ratio was also been evaluated by checking the expression level of NFkB and Bcl-2 and showing that SA10 has two-fold increase in the inhibitory mechanism than SA. This result demonstrates that SA10 acts as an NFkB inhibitor and an apoptosis inducer. Further, molecular docking and simulation have been performed to get insights into the possible inhibitory mechanism of SA and SA10 on NFkB at the atomistic level. The molecular docking results exemplify that both SA and SA10 bind to the active site of NFkB, thereby interfering with the association between DNA and NFkB. SA10 exhibits a more robust binding affinity than SA and is firmly docked well into the interior of the NFkB, as confirmed by MM-PBSA calculations. In a nutshell, the Benzimidazole scaffold containing SA10 has shown more NFkB inhibitory activity in K562 cells than SA, which could be helpful as an ideal therapeutic NFkB inhibitor for treating cancers.

FTO-mediated m6A modification alleviates autoimmune uveitis by regulating microglia phenotypes via the GPC4/TLR4/NF-κB signaling axis

Uveitis, a vision-threatening inflammatory disease worldwide, is closely related to resident microglia. Retinal microglia are the main immune effector cells with strong plasticity, but their role in uveitis remains unclear. N6-methyladenosine (m⁶A) modification has been proven to be involved in the immune response. Therefore, we in this work aimed to identify the potentially crucial m⁶A regulators of microglia in uveitis. Through the single-cell sequencing (scRNA-seq) analysis and experimental verification, we found a significant decrease in the expression of fat mass and obesity-associated protein (FTO) in retinal microglia of uveitis mice and human microglia clone 3 (HMC3) cells with inflammation. Additionally, FTO knockdown was found to aggravate the secretion of inflammatory factors and the mobility/chemotaxis of microglia. Mechanistically, the RNA-seq data and rescue experiments showed that glypican 4 (GPC4) was the target of FTO, which regulated microglial inflammation mediated by the TLR4/NF-κB pathway. Moreover, RNA stability assays indicated that GPC4 upregulation was mainly regulated by the downregulation of the m⁶A "reader" YTH domain family protein 3 (YTHDF3). Finally, the FTO inhibitor FB23-2 further exacerbated experimental autoimmune uveitis (EAU) inflammation by promoting the GPC4/TLR4/NF-κB signaling axis, and this could be attenuated by the TLR4 inhibitor TAK-242. Collectively, a decreased FTO could facilitate microglial inflammation in EAU, suggesting that the restoration or activation of FTO function may be a potential therapeutic strategy for uveitis.

Repurposing Multiple-Molecule Drugs for COVID-19-Associated Acute Respiratory Distress Syndrome and Non-Viral Acute Respiratory Distress Syndrome via a Systems Biology Approach and a DNN-DTI Model Based on Five Drug Design Specifications

The coronavirus disease 2019 (COVID-19) epidemic is currently raging around the world at a rapid speed. Among COVID-19 patients, SARS-CoV-2-associated acute respiratory distress syndrome (ARDS) is the main contribution to the high ratio of morbidity and mortality. However, clinical manifestations between SARS-CoV-2-associated ARDS and non-SARS-CoV-2-associated ARDS are quite common, and their therapeutic treatments are limited because the intricated pathophysiology having been not fully understood. In this study, to investigate the pathogenic mechanism of SARS-CoV-2-associated ARDS and non-SARS-CoV-2-associated ARDS, first, we constructed a candidate host-pathogen interspecies genome-wide genetic and epigenetic network (HPI-GWGEN) via database mining. With the help of host-pathogen RNA sequencing (RNA-Seq) data, real HPI-GWGEN of COVID-19-associated ARDS and non-viral ARDS were obtained by system modeling, system identification, and Akaike information criterion (AIC) model order selection method to delete the false positives in candidate HPI-GWGEN. For the convenience of mitigation, the principal network projection (PNP) approach is utilized to extract core HPI-GWGEN, and then the corresponding core signaling pathways of COVID-19-associated ARDS and non-viral ARDS are annotated via their core HPI-GWGEN by KEGG pathways. In order to design multiple-molecule drugs of COVID-19-associated ARDS and non-viral ARDS, we identified essential biomarkers as drug targets of pathogenesis by comparing the core signal pathways between COVID-19-associated ARDS and non-viral ARDS. The deep neural network of the drug–target interaction (DNN-DTI) model could be trained by drug–target interaction databases in advance to predict candidate drugs for the identified biomarkers. We further narrowed down these predicted drug candidates to repurpose potential multiple-molecule drugs by the filters of drug design specifications, including regulation ability, sensitivity, excretion, toxicity, and drug-likeness. Taken together, we not only enlighten the etiologic mechanisms under COVID-19-associated ARDS and non-viral ARDS but also provide novel therapeutic options for COVID-19-associated ARDS and non-viral ARDS.

NOX2-Deficient Neutrophils Facilitate Joint Inflammation Through Higher Pro-Inflammatory and Weakened Immune Checkpoint Activities

Immune-mediated arthritis is an important chronic inflammatory disease of joints causing debilitating morbidity in affected patients. The mechanisms underlying immune-mediated arthritis have been intensively investigated, however the cellular and molecular factors contributing to the joint inflammation in different redox conditions have not been clearly elucidated. Previous research showed that phagocyte-produced reactive oxygen species (ROS) plays an anti-inflammatory role in K/BxN serum-transfer arthritis and NOX2-deficient mice tend to have more severe arthritis. Although many leukocytes play critical roles in the development of immune-mediated arthritis, the role of neutrophils, which are the main producers of ROS in inflammation, is still controversial. We hence assessed the immunomodulatory function of neutrophils from arthritic joints of NOX2-deficient and wild type mice in this study. We found more neutrophils accumulation in NOX2-deficient inflamed joints. RNA-sequencing and quantitative PCR revealed significantly increased expression of acute inflammation genes including IL1b, Cxcl2, Cxcl3, Cxcl10 and Mmp3 in activated neutrophils from the inflamed joints of NOX2-deficient mice. Moreover, gene set enrichment analysis (GSEA) showed enriched gene signatures in type I and II IFN responses, IL-6-JAK-STAT3 signaling pathway and TNF-α signaling pathway via NF-κB in NOX2-deficient neutrophils. In addition, we found that NOX2-deficient neutrophils expressed lower levels of PD-L1 and were less suppressive than WT neutrophils. Moreover, treatment of PD-L1-Fc decreased cytokine expression and ameliorated the severity of inflammatory arthritis. Our results suggest that NOX2-derived ROS is critical for regulating the function and gene expression in arthritic neutrophils. Both the strong pro-inflammatory and weakened anti-inflammatory functions of neutrophils due to abnormal redox regulation may be targets of treatment for immune-mediated arthritis.

Targeting the integrated stress response in ophthalmology

Purpose: To summarize the Integrated Stress Response (ISR) in the context of ophthalmology, with special interest on the cornea and anterior segment. Results: The ISR is a powerful and conserved signaling pathway that allows for cells to respond to a diverse array of both intracellular and extracellular stressors. The pathway is classically responsible for coordination of the cellular response to amino acid starvation, ultraviolet light, heme dysregulation, viral infection, and unfolded protein. Under normal circumstances, it is considered pro-survival and a necessary mechanism through which protein translation is controlled. However, in cases of severe or prolonged stress the pathway can promote apoptosis, and loss of normal cellular phenotype. The activation of this pathway culminates in the global inhibition of cap-dependent protein translation and the canonical expression of the activating transcription factor 4 (ATF4). Conclusion:The eye is uniquely exposed to ISR responsive stressors due to its environmental exposure and relative isolation from the circulatory system which are necessary for its function. We will discuss how this pathway is critical for the proper function of the tissue, its role in development, as well as how targeting of the pathway could alleviate key aspects of diverse ophthalmic diseases.

Repurposing bortezomib for choroidal neovascularization treatment via antagonizing VEGF-A and PDGF-D mediated signaling

Neovascular age-related macular degeneration (neoAMD) is the leading cause of blindness in AMD and manifests as choroidal neovascularization (CNV). Anti-vascular endothelial growth factor (VEGF) therapies are the mainstay treatments but with limited efficacy and cause detrimental effects on the retina after long-term application. These disadvantages warrant alternative strategy. Herein, we examined the effect on CNV by intravitreal injection of bortezomib, a reversible proteasome inhibitor, and further dissected the mechanism. Krypton red Laser was used to create CNV model in mice. The angiogenesis volume was assessed in choroidal flat-mount with isolectin GS-IB4 labeling and the leakage was examined with fluorescein fundus angiography. Injection of Bor_sub inhibited angiogenesis in the CNV model which was dose-dependent; the injection significantly inhibited leakage as well. Furthermore, Bor_sub injection reduced the contents of VEGF-A, macrophage chemotactic factor 1 (MCP-1), and platelet-derived growth factor (PDGF)-D but not PDGF-B, examined by enzyme-linked immunosorbent assay, in choroid/retinal pigment epithelium (RPE) tissue. These injections also reduced phospho-VEGFR-2 and phospho-PDGFRβ in choroid/RPE tissue examined by immunoblotting. Moreover, Bor_sub inhibited the recruitment of mural cells or macrophages to laser-injured spots. Injection of Bor_sub indicated negative effect on scotopic and photopic responses recorded by electroretinogram. Altogether, intravitreal injection of Bor_sub significantly reduced CNV by antagonizing VEGF-A/Flk-1 and PDGF-D/PDGFRβ pathways without impacting electroretinography parameters. Thus, Bor_sub may offer an invaluable therapy for the prevention and treatment of neoAMD.

Chitosan Oligosaccharides Suppress Nuclear Factor-Kappa B Activation and Ameliorate Experimental Autoimmune Uveoretinitis in Mice

We investigated the therapeutic potential and mechanism of chitosan oligosaccharides (COS) for experimental autoimmune uveoretinitis (EAU) in mice. EAU was induced in C57/BL6 mice by injection of human interphotoreceptor retinoid-binding protein (IRBP) peptides. At the same time, a high or low dose (20 or 10 mg/kg) of COS or phosphate-buffered saline (PBS) was given to mice daily after EAU induction. We found that mouse EAU is ameliorated by the high-dose COS treatment when compared with PBS treatment. In the retinas of high-dose COS-treated mice, the nuclear translocation of NF-κB subunit (p65) was suppressed, and the expression of several key EAU inflammatory mediators, IFN-γ, TNF-α, IL-1α, IL-4, IL-5, IL-6, IL-10, IL-17 and MCP-1 was lowered. These results suggest that COS may be a potential treatment for posterior uveitis.

Suppression of the Reactive Oxygen Response Alleviates Experimental Autoimmune Uveitis in Mice

Reactive oxygen species (ROS) are produced by host phagocytes and play an important role in antimicrobial actions against various pathogens. Autoimmune uveitis causes blindness and severe visual impairment in humans at all ages worldwide. However, the role of ROS in autoimmune uveitis remains unclear. We used ROS-deficient (Ncf1^−/−) mice to investigate the role of ROS in experimental autoimmune uveitis (EAU). Besides, we also used the antioxidant N-acetylcysteine (NAC) treatment to evaluate the effect of suppression of ROS on EAU in mice. The EAU disease scores of Ncf1^−/− mice were significantly lower than those of wild-type mice. EAU induction increased the levels of cytokines (interleukin (IL)-1α, IL-1β, IL-4, IL-6, IL-12, IL-17, and tumor necrosis factor (TNF)-α) and chemokines (monocyte chemoattractant protein (MCP)-1) in the retinas of wild-type mice but not in those of Ncf1^−/− mice. EAU induction enhanced the level of NF-κB activity in wild-type mice. However, the level of NF-κB activity in Ncf1^−/− mice with EAU induction was low. Treatment with the antioxidant NAC also decreased the severity of EAU in mice with reduced levels of oxidative stress, inflammatory mediators, and NF-κB activation in the retina. We successfully revealed a novel role of ROS in the pathogenesis of EAU and suggest a potential antioxidant role for the treatment of autoimmune uveitis in the future.

Acute Bilateral Anterior Uveitis following Cyclophosphamide/ Bortezomid/Dexamethasone (CyBorD) Protocol in a Newly Diagnosed Multiple Myeloma Patient with Concomitant Use of Zoledronic Acid

Purpose: To report a case of anterior uveitis in a patient under treatment with Cyclophosphamide / Bortezomid / Dexamethasone (CyBorD) protocol for Multiple Myeloma and concomitant use of Zoledronic acid.Methods: Observational case report of a 50-year-old woman presenting with acute, severe, bilateral uveitis on a medical history of Multiple Myeloma, undergoing the first cycle of CyBorD protocol, including infusion with Zoledronic acid.Results: Continuation of therapy, with parallel treatment with topical and per os steroids led to resolution of the inflammation. Three more chemotherapy cycles were performed with the same protocol including Zoledronic acid at a lower dosage and were all, uneventful.Conclusion: Our case mirrored uveitis cases with either masquerade syndrome due to Multiple Myeloma or following Zoledronic acid infusion, despite concomitant usage of Dexamethasone and Cyclophosphamide. Three consecutive rechallenges were performed without any topical prophylactic treatment and with no relapse of signs or symptoms.

The VR23 Antitumor Compound Also Shows Strong Anti-Inflammatory Effects in a Human Rheumatoid Arthritis Cell Model and Acute Lung Inflammation in Mice

We previously found that the novel VR23 proteasome inhibitor not only possesses an effective antitumor activity without causing any ill effects to animals but also reduces side effects caused by a partner drug when used in combination. In this article, we report that VR23, unlike other proteasome inhibitors, exhibits potent anti-inflammatory activity. In the LPS-induced THP-1 monocyte model, VR23 downregulates proinflammatory cytokines IL-1β, TNF-α, IL-6, and IL-8 at a similar efficacy to dexamethasone. In contrast, two well-known proteasome inhibitors, bortezomib and carfilzomib, do not effectively downregulate these proinflammatory cytokines. Data from a study with SW982 synovial cell line and primary human synoviocytes showed that VR23 not only effectively downregulates IL-6 but also inhibits cell migration. Interestingly, the IL-6 downregulation by VR23 was significantly more pronounced in the primary synovial cells from rheumatoid arthritis patients than those from healthy donors, suggesting that VR23 can be selective against rheumatoid arthritis. Finally, VR23 effectively reduces neutrophil migration, TNF-α secretion, and tissue inflammation in mice (female BALB/c strain) with an LPS-induced acute lung injury. Thus, our current data indicate that VR23 can be effective on both acute and chronic inflammatory conditions. Taken together with our previous work, VR23 is not only effective on inflammatory conditions but also applicable to different aspects of cancer control, including the treatment and prevention of tumor development by chronic inflammatory responses.

A cell penetrating peptide from SOCS-1 prevents ocular damage in experimental autoimmune uveitis

We describe an immunosuppressive peptide corresponding to the kinase inhibitory region (KIR) of the intracellular checkpoint protein suppressor of cytokine signaling 1 (SOCS-1) that binds to the phospho-tyrosine containing regions of the tyrosine kinases JAK2 and TYK2 and the adaptor protein MAL, and thereby inhibits signaling downstream from these signaling mediators. The peptide, SOCS1-KIR, is thus capable of downregulating overactive JAK/STAT or NF-kB signaling in somatic cells, including those in many compartments of the eye. Attachment of poly-arginine to this peptide (R9-SOCS1-KIR) allows it to penetrate the plasma membrane in aqueous media. R9-SOCS1-KIR was tested in ARPE-19 cells and was found to attenuate mediators of inflammation by blocking the inflammatory effects of IFNγ, TNFα, or IL-17A. R9-SOCS1-KIR and also protected against TNFα or IL-17A mediated damage to the barrier properties of ARPE-19 cells, as evidenced by immunostaining with the tight junction protein, zona occludin 1 (ZO-1), and measurement of transepithelial electrical resistance (TEER). Experimental autoimmune uveitis (EAU) was generated in B10. RIII mice using a peptide of interphotoreceptor retinal binding protein (IRBP^161-180) as immunogen. Topical administration of R9-SOCS1-KIR, 2 days before (prophylactic), or 7 days after immunization (therapeutic) protected ocular structure and function as seen by fundoscopy, optical coherence tomography (OCT), and electroretinography (ERG). The ability R9-SOCS1-KIR to suppress ocular inflammation and preserve barrier properties of retinal pigment epithelium makes it a potential candidate for treatment of autoimmune uveitis.

Preclinical evaluation of antitumor activity of the proteasome inhibitor MLN2238 (ixazomib) in hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is one of the common malignancies and is an increasingly important cause of cancer death worldwide. Surgery, chemotherapy, and radiation therapy extend the 5-year survival limit in HCC patients by only 6%. Therefore, there is a need to develop new therapeutic approaches for the treatment of this disease. The orally bioavailable proteasome inhibitor MLN2238 (ixazomib) has been demonstrated to have anticancer activity. In the present study, we investigated the preclinical therapeutic efficacy of MLN2238 in HCC cells through in vitro and in vivo models, and examined its molecular mechanisms of action. MLN2238 inhibited cell viability in human HCC cells HepG2, Hep3B, and SNU475 in a time- and dose-dependent manner. Flow cytometry analysis demonstrated that MLN2238 induced G2/M cell cycle arrest and cellular apoptosis in HCC cells. Cell cycle arrest was associated with increased expression levels of p21 and p27. MLN2238-induced apoptosis was confirmed by caspase-3/7 activation, PARP cleavage and caspase-dependent β-catenin degradation. In addition, MLN2238 activated ER stress genes in HCC cells and increased the expression of the stress-inducible gene nuclear protein-1. Furthermore, MLN2238 treatment induced upregulation of myeloid cell leukemia-1 (Mcl-1) protein, and Mcl-1 knockdown sensitized HCC cells to MLN2238 treatment, suggesting the contribution of Mcl-1 expression to MLN2238 resistance. This result was also confirmed using the novel Mcl-1 small molecule inhibitor A1210477. Association of A1210477 and MLN2238 determined synergistic antitumor effects in HCC cells. Finally, in vivo orally administered MLN2238 suppressed tumor growth of Hep3B cells in xenograft models in nude mice. In conclusion, our results offer hope for a new therapeutic opportunity in the treatment of HCC patients.

Bortezomib inhibits proliferation, migration, and TGF-β1-induced epithelial-mesenchymal transition of RPE cells

PURPOSE

Nuclear factor kappa B (NF-κB) plays an important role in the epithelial-mesenchymal transition (EMT) of RPE cells. We investigated the effects of a proteasome inhibitor, bortezomib, on the EMT in RPE cells. In addition, we assessed the influence of bortezomib on regulation of the NF-κB pathway during this process.

METHODS

After treatment with various concentrations of bortezomib, cell viability was analyzed with the water-soluble tetrazolium salt-8 assay, cell-cycle regulation was evaluated with flow cytometry, and cell migration was monitored with in vitro wound healing and Transwell migration assays. To induce fibroblastoid transformation, the RPE cells were treated with recombinant human transforming growth factor (TGF)-β1 (10 ng/ml), and western blot and immunocytochemical analyses were performed to evaluate altered expression of EMT markers after treatment with bortezomib. To verify the effect of bortezomib on shrinkage by myofibroblastic transformation, a contraction assay of the RPE-collagen gel lattice was performed.

RESULTS

Treatment with bortezomib decreased RPE viability in a dose-dependent manner, and flow cytometry revealed that these effects were due to arrest of the G2/M phase cell-cycle. In the in vitro wound healing and Transwell migration assays, treatment with 20 nM bortezomib significantly impeded RPE migration. Treatment with bortezomib also significantly inhibited TGF-β1-induced transdifferentiation of the RPE cells. The effects on proliferation, migration, and the EMT were mediated by regulation of the NF-κB signaling pathway. In addition, bortezomib inhibited contraction of the RPE-collagen gel lattices.

CONCLUSIONS

Bortezomib inhibits myofibroblastic transformation of RPE cells by downregulating NF-κB expression and prevents contraction of the RPE-collagen gel matrix. Thus, bortezomib represents a candidate putative therapeutic agent for management of retinal fibrotic diseases.

Retinal metabolic events in preconditioning light stress as revealed by wide-spectrum targeted metabolomics

INTRODUCTION

Light is the primary stimulus for vision, but may also cause damage to the retina. Pre-exposing the retina to sub-lethal amount of light (or preconditioning) improves chances for retinal cells to survive acute damaging light stress.

OBJECTIVES

This study aims at exploring the changes in retinal metabolome after mild light stress and identifying mechanisms that may be involved in preconditioning.

METHODS

Retinas from 12 rats exposed to mild light stress (1000 lux × for 12 h) and 12 controls were collected one and seven days after light stress (LS). One retina was used for targeted metabolomics analysis using the Biocrates p180 kit while the fellow retina was used for histological and immunohistochemistry analysis.

RESULTS

Immunohistochemistry confirmed that in this experiment, a mild LS with retinal immune response and minimal photoreceptor loss occurred. Compared to controls, LS induced an increased concentration in phosphatidylcholines. The concentration in some amino acids and biogenic amines, particularly those related to the nitric oxide pathway (like asymmetric dimethylarginine (ADMA), arginine and citrulline) also increased 1 day after LS. 7 days after LS, the concentration in two sphingomyelins and phenylethylamine was found to be higher. We further found that in controls, retina metabolome was different between males and females: male retinas had an increased concentration in tyrosine, acetyl-ornithine, phosphatidylcholines and (acyl)-carnitines.

CONCLUSIONS

Besides retinal sexual metabolic dimorphism, this study shows that preconditioning is mostly associated with re-organisation of lipid metabolism and changes in amino acid composition, likely reflecting the involvement of arginine-dependent NO signalling.

15-Deoxy-Δ12,14-Prostaglandin J2 Modifies Components of the Proteasome and Inhibits Inflammatory Responses in Human Endothelial Cells

15-Deoxy-Δ^12,14-prostaglandin J₂ (15d-PGJ₂) is an electrophilic lipid mediator derived from PGD₂ with potent anti-inflammatory effects. These are likely to be due to the covalent modification of cellular proteins, via a reactive α,β-unsaturated carbonyl group in its cyclopentenone ring. This study was carried out to identify novel cellular target(s) for covalent modification by 15d-PGJ₂ and to investigate the anti-inflammatory effects of the prostaglandin on endothelial cells (EC). The data presented here show that 15d-PGJ₂ modifies and inhibits components of the proteasome and consequently inhibits the activation of the NF-κB pathway in response to TNF-α. This, in turn, inhibits the adhesion and migration of monocytes toward activated EC, by reducing the expression of adhesion molecules and chemokines in the EC. The effects are consistent with the covalent modification of 13 proteins in the 19S particle of the proteasome identified by mass spectrometry and the suppression of proteasome function, and were similar to the effects seen with a known proteasome inhibitor (MG132). The ubiquitin-proteasome system has been implicated in the regulation of several inflammatory processes and the observation that 15d-PGJ₂ profoundly affects the proteasome functions in human EC suggests that 15d-PGJ₂ may regulate the progression of inflammatory disorders such as atherosclerosis.