The ERK-cPLA2-ACSL4 axis mediating M2 macrophages ferroptosis impedes mucosal healing in ulcerative colitis.

Ulcerative colitis (UC) is a chronic gastrointestinal disease that can be managed with 5-aminosalicylic acid (5-ASA), the standard treatment for UC. However, the effectiveness of 5-ASA is not always optimal. Our study revealed that despite 5-ASA treatment, cells continued to experience excessive ferroptosis, which may hinder mucosal healing in UC and limit the success of this treatment approach in achieving disease remission. We found that combining 5-ASA with the ferroptosis inhibitor Fer-1 led to a significant inhibition of ferroptosis in macrophages present in the colon tissue, along with an increase in the proportion of M2 macrophages, suggesting that targeting ferroptosis in M2 macrophages could be a potential therapeutic strategy for alleviating UC. Our study also demonstrated that M2 macrophages are more susceptible to ferroptosis compared to M1 macrophages, and this susceptibility is associated with the activated arachidonic acid (AA) metabolism pathway mediated by ERK-cPLA2-ACSL4. Additionally, we found that the expression of cPLA2 gene pla2g4a was increased in the colon of UC patients compared to healthy controls. Furthermore, targeted metabolomics analysis revealed that the combination treatment group, as opposed to the 5-ASA treatment group, exhibited the ability to modulate AA metabolism. Overall, our findings emphasize the importance of addressing macrophage ferroptosis in order to enhance macrophage anti-inflammation, improve mucosal healing, and achieve better therapeutic outcomes for patients with UC.

Ferroptosis: a promising candidate for exosome-mediated regulation in different diseases.

Ferroptosis is a newly discovered form of cell death that is featured in a wide range of diseases. Exosome therapy is a promising therapeutic option that has attracted much attention due to its low immunogenicity, low toxicity, and ability to penetrate biological barriers. In addition, emerging evidence indicates that exosomes possess the ability to modulate the progression of diverse diseases by regulating ferroptosis in damaged cells. Hence, the mechanism by which cell-derived and noncellular-derived exosomes target ferroptosis in different diseases through the system Xc-/GSH/GPX4 axis, NAD(P)H/FSP1/CoQ10 axis, iron metabolism pathway and lipid metabolism pathway associated with ferroptosis, as well as its applications in liver disease, neurological diseases, lung injury, heart injury, cancer and other diseases, are summarized here. Additionally, the role of exosome-regulated ferroptosis as an emerging repair mechanism for damaged tissues and cells is also discussed, and this is expected to be a promising treatment direction for various diseases in the future. Video Abstract.

Enhanced anti-glioma efficacy of doxorubicin with BRD4 PROTAC degrader using targeted nanoparticles.

Current treatment of glioma is hampered due to the physical blood-brain barrier (BBB) and the resistance to traditional chemotherapeutic agents. Herein, we proposed a combined treatment strategy based on Cyclo (Arg-Gly-Asp-d-Phe-Lys) (cRGDfk) peptides-modified nanoparticle named cRGD-P in a self-assembly method for the co-delivery of doxorubicin (DOX) and BRD4 PROTAC degrader ARV-825 (ARV). Molecular dynamics simulations showed that cRGD-P could change its conformation to provide interaction sites for perfectly co-loading DOX and ARV. The cRGD-P/ARV-DOX exhibited an average size of 39.95 â€‹nm and a zeta potential of -0.25 â€‹mV. Increased expression of BRD4 in glioma cells was observed after being stimulated by cRGD-P/DOX, confirming one of the possible mechanisms of DOX resistance and the synergistic tumor inhibition effect of BRD4 degrading ARV combined with DOX. In the study, the combination of DOX and ARV in the cRGD-P nanoparticle system exhibited synergistic suppression of tumor growth in glioma cells on account of cell cycle arrest in the G2/M phase and the activation of tumor cells apoptosis-related pathways including triggering caspase cascade and downregulating Bcl-2 as well as upregulating Bax. The cRGD-P/ARV-DOX system could effectively suppress the heterotopic and orthotopic growth of glioma by increasing tumor apoptosis, inhibiting tumor proliferation, and decreasing tumor angiogenesis in vivo. Therefore, the cRGD-modified nanoparticle to co-deliver DOX and ARV provides a potential platform for exploiting a more effective and safer combination therapy for glioma.

A BRD4 PROTAC nanodrug for glioma therapy via the intervention of tumor cells proliferation, apoptosis and M2 macrophages polarization.

Glioma is a primary aggressive brain tumor with high recurrence rate. The poor efficiency of chemotherapeutic drugs crossing the blood‒brain barrier (BBB) is well-known as one of the main challenges for anti-glioma therapy. Moreover, massive infiltrated tumor-associated macrophages (TAMs) in glioma further thwart the drug efficacy. Herein, a therapeutic nanosystem (SPP-ARV-825) is constructed by incorporating the BRD4-degrading proteolytic targeting chimera (PROTAC) ARV-825 into the complex micelle (SPP) composed of substance P (SP) peptide-modified poly(ethylene glycol)-poly(d,l-lactic acid)(SP-PEG-PDLLA) and methoxy poly(ethylene glycol)-poly(d,l-lactic acid) (mPEG-PDLLA, PP), which could penetrate BBB and target brain tumor. Subsequently, released drug engenders antitumor effect via attenuating cells proliferation, inducing cells apoptosis and suppressing M2 macrophages polarization through the inhibition of IRF4 promoter transcription and phosphorylation of STAT6, STAT3 and AKT. Taken together, our work demonstrates the versatile role and therapeutic efficacy of SPP-ARV-825 micelle against glioma, which may provide a novel strategy for glioma therapy in future.

Co-Delivery of Paclitaxel and shMCL-1 by Folic Acid-Modified Nonviral Vector to Overcome Cancer Chemotherapy Resistance.

Acquired chemoresistance presents a major clinical impediment, which is an urgent problem to be solved. Interestingly, myeloma cell leukemia-1 (MCL-1) and folate receptor expression levels are higher in chemotherapy-resistant patients than in pretreatment patients. In this study, a multifunctional folic acid (FA)-targeting core-shell structure is presented for simultaneous delivery of shMCL-1 and paclitaxel (PTX). The transfection efficiency of shMCL-1 with the FA-targeting delivery system is higher than with a nontargeting delivery system in Skov3 and A2780T cells. The FA-targeting system significantly inhibits cell growth, blocks cell cycles, and promotes apoptosis of cancer cells in vitro. The mechanisms involved in inhibiting growth are related to Bcl-2/Bax and cdc2/Cyclin B1 pathways. An analysis of RNA sequencing suggests that shMCL-1 reverses chemoresistance through regulating genes such as regulator of chromosome condensation 2 (RCC2). The synergetic effect of shMCL-1 and PTX effectively inhibits tumor growth in both PTX-resistant and normal cancer models by inducing tumor apoptosis, inhibiting proliferation, and limiting tumor angiogenesis. The study results indicate that a FA-targeting delivery system combining shMCL-1 with PTX can simultaneously target tumor sites and restore the sensitivity of chemotherapy-resistant cancer to PTX. These findings have important implications for patients with normal or PTX-resistant cancer.

The regulatory effect of acetylation of HMGN2 and H3K27 on pyocyanin-induced autophagy in macrophages by affecting Ulk1 transcription.

Pyocyanin (PYO) is a major virulence factor secreted by Pseudomonas aeruginosa, and autophagy is a crucial homeostatic mechanism for the interaction between the pathogens and the host. It remains unknown whether PYO leads to autophagy in macrophages by regulating histone acetylation. The high mobility group nucleosomal binding domain 2 (HMGN2) has been reported to regulate the PYO-induced autophagy and oxidative stress in the epithelial cells; however, the underlying molecular mechanism has not been fully elucidated. In this study, PYO was found to induce autophagy in macrophages, and the mechanism might be correlated with the up-regulation of HMGN2 acetylation (HMGN2ac) and the down-regulation of H3K27 acetylation (H3K27ac) by modulation of the activities of acetyltransferases and deacetylases. Moreover, we further demonstrated that the up-regulated HMGN2ac enhances its recruitment to the Ulk1 promoter, while the down-regulation of H3K27ac reduces its recruitment to the Ulk1 promoter, thereby promoting or inhibiting the transcription of Ulk1. In conclusion, HMGN2ac and H3K27ac play regulatory roles in the PYO-induced autophagy in macrophages.

Improving Anti-Inflammatory Effect of Luteolin with Nano-Micelles in the Bacteria-Induced Lung Infection.

The effective therapy for lung infectious diseases became more and more difficult since the severe antibiotic resistance of pathogenic microorganisms, it is urgent to develop new antimicrobial agents. Luteolin has been reported to play a crucial part in host immune responses. However, the clinical use of luteolin is impeded due to its hydrophobicity and low oral bioavailability. In this study, we formulated luteolin-loaded Methoxy poly(ethylene glycol)-poly(lactide) micelles (luteolin/MPEG-PLA), to improve the bioavailability of luteolin in lung infectious diseases. The results showed that luteolin/MPEG-PLA treatment could reduce the adhesion of Klebsiella pneumoniae (K. pneumoniae) to lung epithelial cells and enhance the germicidal ability of macrophages against K. pneumoniae compared to untreated group. Meanwhile, luteolin/MPEG-PLA showed stronger adhesion resistance of epithelial cells and germicidal ability of macrophages compared with free luteolin. In vivo study, luteolin/MPEG-PLA administration significantly promoted the clearance of bacteria and reduced inflammatory infiltration of lung tissue in K. pneumoniae induced lung infectious mice model. Further studies showed that treatment with luteolin/MPEG-PLA reduced the mRNA expression of LPS-induced inflammatory cytokines and chemokines in macrophages significantly. In general, luteolin/MPEG-PLA can enhance the anti-bacterial ability of lung epithelial cells and macrophages, and has a stronger therapeutic effect than free luteolin in bacterial-induced lung infection. Luteolin/MPEG-PLA may be an excellent potential drug for bacterial-induced lung infectious diseases treatment.

Brd4 inhibition ameliorates Pyocyanin-mediated macrophage dysfunction via transcriptional repression of reactive oxygen and nitrogen free radical pathways.

Macrophages play critical roles in the first-line immune defense against airway infections caused by Pseudomonas aeruginosa (PA). The redox-active phenazine-pyocyanin (PCN), as one of the most essential virulence factors, facilities PA-related infection via a wide spectrum of cellular oxidative damages. However, little is known for PCN cytotoxicity in macrophages. In this study, besides showing PCN-mediated reactive oxygen species (ROS) indeed involved in macrophage viability and function impairment, we at the first time demonstrated a novel role of reactive nitrogen species (RNS) pathway causing cellular damage in PCN-challenged macrophages. Using small molecule inhibitor JQ1 targeting Bromodomain and extra-terminal family proteins, we showed restrained iNOS-dependent nitric oxide (NO) production correlated with abolished Brd4 recruitment to the NOS2 (encoding inducible nitric oxide synthase-iNOS) promoter. Application of JQ1 diminished PCN-mediated peroxynitrite (ONOO-) that followed ROS and NO induction, restored macrophage survival and bacteria clearance as well as repressed local inflammation in PA/PCN-challenged mice lungs. Our results uncover a novel link between PCN-mediated macrophage dysfunction and reactive free radicals that rely on Brd4-dependent transcription modulation of multiple stress-response genes, suggesting Brd4 could be a promising therapeutic target in treating PA-related lung infection.

Anti-Glioma Effect with Targeting Therapy Using Folate Modified Nano-Micelles Delivery Curcumin.

Targeted drug delivery systems have currently demonstrated considerable potential clinical benefits in cancer treatment. Curcumin has become a candidate anti-tumor drug for the therapy of glioblastoma multiforme (GBM) by increasing cell apoptosis and suppressing cell proliferation. In current research, we explored a novel targeted drug delivery system with a self-assembly measure by curcumin, MPEG-PLA and Fa-PEG-PLA. Compared with free curcumin and Cur/MPEG-PLA, Cur/Fa-PEG-PLA can remarkably suppress the growth of GL261 cells and promote apoptotic rate. Moreover, after the procession of tumor-bearing mice with curcumin/Fa-PEG-PLA complex, tumor growth in subcutaneous and intracranial tumor models were repressed via suppressing angiogenesis and facilitating apoptosis in vivo. The Curcumin/Fa-PEG-PLA nanoparticle may be a novel drug for the therapy of GBM.

Glutaredoxin 1 up-regulates deglutathionylation of α4 integrin and thereby restricts neutrophil mobilization from bone marrow.

α4 integrin plays a crucial role in retention and release of neutrophils from bone marrow. Although α4 integrin is known to be a potential target of reactive oxygen species (ROS)-induced cysteine glutathionylation, the physiological significance and underlying regulatory mechanism of this event remain elusive. Here, using in vitro and in vivo biochemical and cell biology approaches, we show that physiological ROS-induced glutathionylation of α4 integrin in neutrophils increases the binding of neutrophil-associated α4 integrin to vascular cell adhesion molecule 1 (VCAM-1) on human endothelial cells. This enhanced binding was reversed by extracellular glutaredoxin 1 (Grx1), a thiol disulfide oxidoreductase promoting protein deglutathionylation. Furthermore, in a murine inflammation model, Grx1 disruption dramatically elevated α4 glutathionylation and subsequently enhanced neutrophil egress from the bone marrow. Corroborating this observation, intravenous injection of recombinant Grx1 into mice inhibited α4 glutathionylation and thereby suppressed inflammation-induced neutrophil mobilization from the bone marrow. Taken together, our results establish ROS-elicited glutathionylation and its modulation by Grx1 as pivotal regulatory mechanisms controlling α4 integrin affinity and neutrophil mobilization from the bone marrow under physiological conditions.

Non-histone nuclear protein HMGN2 differently regulates the urothelium barrier function by altering expression of antimicrobial peptides and tight junction protein genes in UPEC J96-infected bladder epithelial cell monolayer.

The urinary tract is vulnerable to frequent challenges from environmental microflora. Uropathogenic Escherichia coli (UPEC) makes a major contribution to urinary tract infection (UTI). Previous studies have characterized positive roles of non-histone nuclear protein HMGN2 in lung epithelial innate immune response. In the study presented here, we found HMGN2 expression was up-regulated in UPEC J96-infected urothelium. Surprisingly, over-expression of HMGN2 promoted disruption of BECs 5637 cells' intercellular junctions by down-regulating tight junction (TJs) components' expression and physical structure under J96 infection. Further investigation showed that BECs 5637 monolayer, in which HMGN2 was over-expressed, had significantly increased permeability to J96. Our study systemically explored the regulatory roles of HMGN2 in BECs barrier function during UPEC infection and suggested different modulations of intracellular and paracellular routes through which UPEC invades the bladder epithelium.

The modulation of MiR-155 and MiR-23a manipulates Klebsiella pneumoniae Adhesion on Human pulmonary Epithelial cells via Integrin α5ß1 Signaling.

Micro-RNAs (miRNAs) critically regulate several host defense mechanisms, but their roles in the bacteria-epithelium interplay remain unclear. Our results displayed that the expression of miR-155 and miR-23a were down-regulated in K. pneumoniae-infected pulmonary epithelial cells. The elevated bacterial adhesion on A549 cells followed the enhancement of the cellular levels of these two miRNAs. Meanwhile, a mechanistic study demonstrated that miR-155 promoted integrin α5ß1 function and resulted in the increased actin polymerization. Moreover, a non-histone nuclear protein, high mobility group nucleosomal-binding domain 2 (HMGN2) served as the potential target of miR-155 and miR-23a to regulate the integrin α5ß1 expression and K. pneumoniae adhesion. Furthermore, the expression of a known integrin transcription suppressor-Nuclear Factor-I (NFI) was also repressed by miR-155, which paralleled with its chromatin location in the promoter regions of integrin α5 and ß1. These results uncover novel links between miRNAs and integrin function to regulate bacterial adhesion, indicating a potential mechanism of host cell autonomous immune response to K. pneumoniae infection.