Advancements of Annexin A1 in inflammation and tumorigenesis

Assessment of Phage-Displayed Peptides Targeting Cancer Cell Surface Proteins: A Comprehensive Molecular Docking Study

Peptides binding overexpressed breast and cervical cancer cell surface proteins can be isolated by phage display technology, and their affinity to their potential receptors can be assessed by molecular docking. We isolated 44 phage clones displaying dodecapeptides with high affinity to HeLa cervical cancer and MDA-MB-231 (MDA) breast cancer cells by repeated biopanning of an MK13 phage library and explored their affinity to specific proteins by molecular docking. Six peptides appeared repeatedly during biopanning: two with affinity to HeLa (H5/H21), and four with affinity to MDA cells (M3/M7/M15/M17). Peptide pairs M3/H5 and H1/M17 had affinity to both cell lines. A systematic review identified Annexin A2, EGFR, CD44, CD146, and Integrin alpha V as potential protein targets in HeLa cells, and Vimentin, Galectin-1, and Annexins A1 and A5 in MDA cells. Via virtual screening, we selected six peptides with the highest total docking scores: H1 (-916.32), H6 (-979.21), H19 (-1093.24), M6 (-732.21), M16 (-745.5), and M19 (-739.64), and identified that docking scores were strengthened by the protein type, the interacting amino acid side chains, and the polarity of peptides. This approach facilitates the selection of relevant peptides that could be further explored for active targeting in cancer diagnosis and treatment.

Biomechanical Insights into the Proteomic Profiling of Cells in Response to Red Light Absorption

Photobiomodulation (PBM) is a promising non-invasive therapy for tissue repair, but its underlying cellular mechanisms are not fully understood. In this study, the biomechanical and proteomic responses of three cell types - keratinocytes (HACAT), fibroblasts (L929), and osteoblasts (OFCOLII) - exposed to red light (633 nm) are investigated using atomic force microscopy (AFM) and mass spectrometry-based proteomic analysis. Red light absorption resulted in cell-type-specific changes in viscoelastic properties, with fibroblasts exhibiting increased fluidity, reduced stiffness, and enhanced motility. Conversely, keratinocytes exhibited intensity-dependent responses, while osteoblasts appeared to be relatively insensitive to irradiation conditions. Proteomic profiling identified key signaling pathways involved in immune response, ATP production, and stress regulation. The immune and ATP pathways are strongly linked to the modulation of viscoelastic properties, particularly in fibroblasts, while weaker correlations were observed in keratinocytes. Cytoskeletal remodeling, primarily within the F-actin network, is identified as the main driver of mechanical alterations, with additional contributions from microtubules and intermediate filaments. These findings provide new insights into how red light absorption modulates cellular viscoelasticity through cytoskeletal remodeling, with potential applications in optimizing light-based therapies for tissue regeneration and disease treatment.

Identification of ANXA1 as a Novel Upstream Negative Regulator of Notch1 Function in AML

Abnormal Notch1 expression has an important role in tumorigenesis. However, upstream control mechanisms for Notch1 are still insufficiently understood. Acute myeloid leukemia (AML) is one of the most common and lethal blood malignancies with limited possibilities for treatment. Thus, new therapeutic targets are urgently needed to improve current ineffective therapies. Herein, high Annexin A1 (ANXA1) expression is found correlated with hyperproliferation of AML cells, and then ANXA1 is identified as a novel negative regulator of Notch1 function in AML. Mechanistically, ANXA1 directly bound to the intracellular domain of Notch1 (NICD) to target this tumor suppressor for degradation. Furthermore, NICD executed its tumor suppressive function through activation of the p15 promoter. Thus, ablation of the Notch1-p15-mediated tumor suppression by ANXA1 provided a novel mechanism of AML proliferation. In human AML patients, a mutual exclusive relation is discovered between ANXA1 and Notch1/p15, corroborating mechanistic discovery. On the basis of these results, it is reasonably speculated that targeting ANXA1 would provide an effective approach for treatment of AML. In support of this new therapeutic paradigm, provided proof-of-concept data by antagonizing ANXA1 using NICD inhibitory peptides.

Label-free quantitative proteomic profiling reveals differential plasma protein expression in patients with obesity after treatment with liraglutide

Introduction

Treatment and management of obesity is clinically challenging. The inclusion of GLP-1 receptor agonists (GLP1RA) in the medical management of obesity has proven to be efficacious. However, mechanisms underlying the molecular changes arising from GLP1RA treatment in patients with obesity remain to be elucidated.

Methods

A single-center, prospective study was undertaken to evaluate the changes in the plasma proteins after liraglutide 3 mg therapy in twenty patients (M/F: 7/13) with obesity (mean BMI 40.65 ± 3.7 kg/m2). Anthropometric and laboratory parameters were measured, and blood samples were collected at two time points: baseline, before initiating treatment (pretreatment group, PT), and after three months of receiving the full dose liraglutide 3 mg (posttreatment group, PoT). An untargeted label-free LC MSMS mass spectrometric approach combined with bioinformatics and network pathway analysis was used to determine changes in the proteomic profiles.

Results

The mean age of the study participants was 36.0 ± 11.1 years. A statistically significant change was observed in weight, BMI and HbA1c levels between the PT and PoT groups (paired t-test, P < 0.001). A significant dysregulation was noted in the abundances of 151 proteins (31 up and 120 downregulated) between the two groups. The potential biomarkers were evaluated using receiver operating characteristic (ROC) curves. The top ten proteins (area under the curve (AUC) of 0.999 (95% CI)) were identified as potential biomarkers between PT and PoT groups and included Cystatin-B, major vault protein, and plastin-3, which were upregulated, whereas multimerin-2, large ribosomal P2, and proline-rich acidic protein 1 were downregulated in the PoT group compared with the PT group. The top network pathway identified using ingenuity pathway analysis (IPA), centered around dysregulation of MAPK, AKT, and PKc signaling pathways and related to cell-to-cell signaling and interaction, cellular assembly and organization, cellular compromise and a score of 46 with 25 focus proteins.

Discussion

Through label-free quantitative proteomic analysis, our study revealed significant dysregulation of plasma proteins after liraglutide 3 mg treatment in patients with obesity. The alterations in the proteomic profile between the PT and PoT groups demonstrated a decrease in levels of proteins involved in inflammation and oxidative stress pathways. On the other hand proteins involved in the glycolytic and lipolytic metabolic pathways as well as those participating in cytoskeletal and endothelial reorganization were observed to be increased. Understanding actions of liraglutide at a molecular and proteomic levels provides a holistic look into how liraglutide impacts metabolism, induces weight loss and improves overall metabolic health.

Implication of the Annexin 1/FPR axis in leishmanial exosome-mediated Leishmania major skin hyperpathogenesis

Introduction

Exosomes produced by the protozoan parasite Leishmania (LeishEXO) are well-established drivers of virulence, though mechanisms underlying their exacerbation of experimental leishmaniasis remain elusive. Expression of Annexin A1 (ANXA1), a protein implicated in exosome-mediated pathologies and viral internalization, has been shown to correlate with cutaneous leishmaniasis severity. Given ANXA1's regulation of myeloid cells - the canonical hosts for Leishmania - we studied the potential role of ANXA1 and its receptors FPR1/2 in exerting LeishEXO's effects.

Methods

Murine and in vitro ANXA1-/- models were used to study the generation of protective TH1 responses during experimental L. major infection with and without LeishEXO. Recruitment of inflammatory cells was assessed using a peritoneal cell recruitment assay and immunophenotyping, and production of inflammatory mediators was measured using a cytokine and chemokine array. Treatment of experimental models with FPR2 antagonist WRW4 and FPR1/2 agonist WKYMVm was used to delineate the role of the FPR/ANXA1 axis in LeishEXO-mediated hyperpathogenesis.

Results

We established that ANXA1 deficiency prohibits LeishEXO-mediated pathogenesis and myeloid cell infection, with minimal alterations to adaptive and innate immune phenotypes. FPR2 blockade with WRW4 similarly inhibited leishmanial hyperpathogenesis, while direct activation of FPRs with WKYMVm enhanced infection and recapitulated the LeishEXO-mediated phenotype. This research describes LeishEXO's utilization of the ANXA1/FPR axis to facilitate parasitic internalization and pathogenesis, which may be leveraged in the development of therapeutics for leishmaniasis.

Current State of Knowledge on Blood and Tissue-Based Biomarkers for Opisthorchis viverrini-induced Cholangiocarcinoma: A Review of Prognostic, Predictive, and Diagnostic Markers

Cholangiocarcinoma (CCA) is a prevalent cancer in Southeast Asia, with Opisthorchis viverrini (O.viverrini) infection being the primary risk factor. Most CCA cases in this region are diagnosed at advanced stages, leading to unfavorable prognoses. The development of stage-specific biomarkers for Opisthorchis viverrini-induced cholangiocarcinoma (Ov-CCA) holds crucial significance, as it facilitates early detection and timely administration of curative interventions, effectively mitigating the high morbidity and mortality rates associated with this disease in the Great Mekong region. Biomarkers are a promising approach for early detection, prognosis, and targeted treatment of CCA. Disease-specific biomarkers facilitate early detection and enable monitoring of therapy effectiveness, allowing for any necessary corrections. This review provides an overview of the potential O. viverrini-specific molecular biomarkers and important markers for diagnosing and monitoring Ov-CCA, discussing their prognostic, predictive, and diagnostic value. Despite the limited research in this domain, several potential biomarkers have been identified, encompassing both worm-induced and host-induced factors. This review offers a thorough examination of historical and contemporary progress in identifying biomarkers through multiomics techniques, along with their potential implications for early detection and treatment.

The prognostic value of stem cell markers in triple-negative breast cancer

Among the many consecutive theories of cancer, the stem cell theory is currently the most accepted one. Cancer stem cells are located in small niches with specific environment, renew themselves and are believed to be responsible for many recurrences. They can be highlighted with stem cell markers, but often these markers also label tumor cells, and this may represent a phenotypical change associated with prognosis. In this study, we attempted to match tumor outcomes with the expression of the following stem cell markers: ALDH1, AnnexinA1, CD44, CD117, CD166, Nanog and oct-4. Tissue microarray blocks from triple-negative breast cancers were immunostained for the listed markers, and their expression by the majority of tumor cells (diffuse positivity) was correlated with prognosis. Of the 106 tumors investigated, diffuse positivity was seen in 7 (ALDH1), 33 (AnnexinA1), 53 (CD44), 44 (CD117 membranous only), 49 (CD117), 72 (CD166), 19 (Nanog), and 11 (oct-4) cases. With a median follow-up of 83 months, ALDH1 and CD117 expression was associated with DFS, whereas CD44, CD117 and CD166 were associated with OS estimates, based on Kaplan-Meier analyses. In the multivariate Cox proportional hazard models (including the examined markers and clinicopathological data which had a statistical impact in the univariate analysis), the pN category and the lack of ALDH1 expression were independent prognosticators for DFS, and the pN category and diffuse CD44 staining were independent prognosticators for OS. In the multivariate analysis including all of the examined clinicopathological data and markers, only CD117 showed a statistical impact on OS. We failed to demonstrate a prognostic impact for most stem cell markers tested in triple-negative breast cancer, but lack of ALDH1 staining and CD44 expression appears as of prognostic value, requiring further examination in independent studies.

Natural Products as Drug Candidates for Redox-Related Human Disease

This Special Issue presented recent progress on natural products that serve as drug candidates for redox-related human diseases [...].

Characterizations of annexin A1-interacting proteins in apical membrane and cytosolic compartments of renal tubular epithelial cells

Annexin A1 (ANXA1) is a multifunctional calcium-binding protein that can bind to membrane phospholipids. Under high-calcium condition, ANXA1 expression increases on renal epithelial cell surface, leading to enhanced adhesion of calcium oxalate (CaOx) crystal (stone material) onto the cells. To regulate various cellular processes, ANXA1 interacts with many other intracellular protein partners. However, components of the ANXA1-interacting protein complex remain unclear. Herein, we characterized the interacting complexes of apical membrane (ApANXA1) and cytosolic (cyANXA1) forms of ANXA1 in apical membrane and cytosolic compartments, respectively, of renal epithelial cells under high-calcium condition using proteomic and bioinformatic approaches. After fractionation, the ApANXA1- and CyANXA1-interacting partners were identified by immunoprecipitation followed by nanoLC‑ESI‑Qq-TOF tandem mass spectrometry (IP-MS/MS). The ANXA1-interacting partners that were common in both apical membrane and cytosolic compartments and those unique in each compartment were then analyzed for their physico-chemical properties (molecular weight, isoelectric point, amino acid contents, instability index, aliphatic index, and grand average of hydropathicity), secondary structure (α-helix, β-turn, random coil, and extended strand), molecular functions, biological processes, reactome pathways and KEGG pathways. The data demonstrated that each set of these interacting proteins exhibited common and unique characteristics and properties. The knowledge from this study may lead to better understanding of the ApANXA1 and CyAXNA1 biochemistry and functions as well as the pathophysiology of CaOx kidney stone formation induced by high-calcium condition.

The most prominent modulated annexins during parasitic infections

Annexins (ANXs) exert different functions in cell biological and pathological processes and are thus known as double or multi-faceted proteins. These sophisticated proteins might express on both parasite structure and secretion and in parasite-infected host cells. In addition to the characterization of these pivotal proteins, describing their mechanism of action can be also fruitful in recognizing their roles in the pathogenesis of parasitic infections. Accordingly, this study presents the most prominent ANXs thus far identified and their relevant functions in parasites and infected host cells during pathogenesis, especially in the most important intracellular protozoan parasitic infections including leishmaniasis, toxoplasmosis, malaria and trypanosomiasis. The data provided in this study demonstrate that the helminth parasites most probably express and secret ANXs to develop pathogenesis while the modulation of the host-ANXs could be employed as a crucial strategy by intracellular protozoan parasites. Moreover, such data highlight that the use of analogs of both parasite and host ANX peptides (which mimic or regulate ANXs physiological functions through various strategies) might suggest novel therapeutic insights into the treatment of parasitic infections. Furthermore, due to the prominent immunoregulatory activities of ANXs during most parasitic infections and the expression levels of these proteins in some parasitic infected tissues, such multifunctional proteins might be also potentially relevant as vaccine and diagnostic biomarkers. We also suggest some prospects and insights that could be useful and applicable to form the basis of future experimental studies.

Developmental and homeostatic signaling transmitted by the G-protein coupled receptor FPR2

Formyl peptide receptor 2 (FPR2) and its mouse counterpart Fpr2 are the members of the G protein-coupled receptor (GPCR) family. FPR2 is the only member of the FPRs that interacts with ligands from different sources. FPR2 is expressed in myeloid cells as well as epithelial cells, endothelial cells, neurons, and hepatocytes. During the past years, some unusual properties of FPR2 have attracted intense attention because FPR2 appears to possess dual functions by activating or inhibiting intracellular signal pathways based on the nature, concentration of the ligands, and the temporal and spatial settings of the microenvironment in vivo, the cell types it interacts with. Therefore, FPR2 controls an abundant array of developmental and homeostatic signaling cascades, in addition to its "classical" capacity to mediate the migration of hematopoietic and non-hematopoietic cells including malignant cells. In this review, we summarize recent development in FPR2 research, particularly in its role in diseases, therefore helping to establish FPR2 as a potential target for therapeutic intervention.

Electrical Stimulation of the Auricular Branch Vagus Nerve Using Random and Alternating Frequencies Triggers a Rapid Onset and Pronounced Antihyperalgesia via Peripheral Annexin A1-Formyl Peptide Receptor 2/ALX Pathway in a Mouse Model of Persistent Inflammatory Pain

This study evaluated the antihyperalgesic and anti-inflammatory effects of percutaneous vagus nerve electrical stimulation (pVNS) by comparing the effects of alternating and random frequencies in an animal model of persistent inflammatory hyperalgesia. The model was induced by Freund's complete adjuvant (CFA) intraplantar (i.pl.) injection. Mice were treated with different protocols of time (10, 20, or 30 min), ear laterality (right, left or both), and frequency (alternating or random). Mechanical hyperalgesia was evaluated, and some groups received i.pl. WRW4 (FPR2/ALX antagonist) to determine the involvement. Edema, paw surface temperature, and spontaneous locomotor activity were evaluated. Interleukin-1β, IL-6, IL-10, and IL4 levels were verified by enzyme-linked immunosorbent assay. AnxA1, FPR2/ALX, neutrophil, M1 and M2 phenotype macrophage, and apoptotic cells markers were identified using western blotting. The antihyperalgesic effect pVNS with alternating and random frequency effect is depending on the type of frequency, time, and ear treated. The pVNS random frequency in the left ear for 10 min had a longer lasting antihyperalgesic effect, superior to classical stimulation using alternating frequency and the FPR2/ALX receptor was involved in this effect. There was a reduction in the levels of pro-inflammatory cytokines and an increase in the immunocontent of AnxA1 and CD86 in mice paw. pVNS with a random frequency in the left ear for 10 min showed to be optimal for inducing an antihyperalgesic effect. Thus, the random frequency was more effective than the alternating frequency. Therefore, pVNS may be an important adjunctive treatment for persistent inflammatory pain.

Annexins A2 and A5 are potential early biomarkers of hepatocarcinogenesis

Hepatocellular carcinoma (HCC) is a highly lethal liver cancer with late diagnosis; therefore, the identification of new early biomarkers could help reduce mortality. We determine the tissue and plasma status of five annexins during hepatocarcinogenesis by diethylnitrosamine-induced cirrhosis-HCC. We found that Anxa5 was the earliest upregulated gene at week 12 after HCC initiation, while Anxa1 and Anxa2 were upregulated in advanced HCC stages (weeks 18 and 22). Furthermore, the protein level of Annexin A1, A2, A5 and A10 was increased from the early stages. Immunofluorescence and subcellular fractionation revealed Annexin A1, A2, and A5 in the cytoplasm and nuclei of tumor cells. Notably, increased plasma levels of Annexin A5 significantly (r² = 0.8203) correlated with Annexin A5 levels in liver tissue from week 12 and gradually increased until week 22. Using the TCGA database, we found that the expression of ANXA2 (HR = 1.7, p = 0.0046) and ANXA5 (HR = 1.8, p = 0.00077) was associated with poor survival in HCC patients. In conclusion, we have identified Annexin A1 and A5 as potentially useful early biomarkers for poor prognosis in HCC patients.

Deletion of Annexin A1 in Mice Upregulates the Expression of Its Receptor, Fpr2/3, and Reactivity to the AnxA1 Mimetic Peptide in Platelets

Annexin A1 (ANXA1) is an endogenous protein, which plays a central function in the modulation of inflammation. While the functions of ANXA1 and its exogenous peptidomimetics, N-Acetyl 2-26 ANXA1-derived peptide (ANXA1_Ac2-26), in the modulation of immunological responses of neutrophils and monocytes have been investigated in detail, their effects on the modulation of platelet reactivity, haemostasis, thrombosis, and platelet-mediated inflammation remain largely unknown. Here, we demonstrate that the deletion of Anxa1 in mice upregulates the expression of its receptor, formyl peptide receptor 2/3 (Fpr2/3, orthologue of human FPR2/ALX). As a result, the addition of ANXA1_Ac2-26 to platelets exerts an activatory role in platelets, as characterised by its ability to increase the levels of fibrinogen binding and the exposure of P-selectin on the surface. Moreover, ANXA1_Ac2-26 increased the development of platelet-leukocyte aggregates in whole blood. The experiments carried out using a pharmacological inhibitor (WRW4) for FPR2/ALX, and platelets isolated from Fpr2/3-deficient mice ascertained that the actions of ANXA1_Ac2-26 are largely mediated through Fpr2/3 in platelets. Together, this study demonstrates that in addition to its ability to modulate inflammatory responses via leukocytes, ANXA1 modulates platelet function, which may influence thrombosis, haemostasis, and platelet-mediated inflammation under various pathophysiological settings.

Targeting Annexin A1 as a Druggable Player to Enhance the Anti-Tumor Role of Honokiol in Colon Cancer through Autophagic Pathway

Colon cancer is one of the most common digestive tract malignancies, having the second highest mortality rate among all tumors, with a five-year survival of advanced patients of only 10%. Efficient, targeted drugs are still lacking in treating colon cancer, so it is urgent to explore novel druggable targets. Here, we demonstrated that annexin A1 (ANXA1) was overexpressed in tumors of 50% of colon cancer patients, and ANXA1 overexpression was significantly negatively correlated with the poor prognosis of colon cancer. ANXA1 promoted the abnormal proliferation of colon cancer cells in vitro and in vivo by regulating the cell cycle, while the knockdown of ANXA1 almost totally inhibited the growth of colon cancer cells in vivo. Furthermore, ANXA1 antagonized the autophagic death of honokiol in colon cancer cells via stabilizing mitochondrial reactive oxygen species. Based on these results, we speculated that ANXA1 might be a druggable target to control colon cancer and overcome drug resistance.

Implicative role of epidermal growth factor receptor and its associated signaling partners in the pathogenesis of Alzheimer's disease

Epidermal growth factor receptor (EGFR) plays a pivotal role in early brain development, although its expression pattern declines in accordance with the maturation of the active nervous system. However, recurrence of EGFR expression in brain cells takes place during neural functioning decline and brain atrophy in order to maintain the homeostatic neuronal pool. As a consequence, neurotoxic lesions such as amyloid beta fragment (Aβ_1-42) formed during the alternative splicing of amyloid precursor protein in Alzheimer's disease (AD) elevate the expression of EGFR. This inappropriate peptide deposition on EGFR results in the sustained phosphorylation of the downstream signaling axis, leading to extensive Aβ_1-42 production and tau phosphorylation as subsequent pathogenesis. Recent reports convey that the pathophysiology of AD is correlated with EGFR and its associated membrane receptor complex molecules. One such family of molecules is the annexin superfamily, which has synergistic relationships with EGFR and is known for membrane-bound signaling that contributes to a variety of inflammatory responses. Besides, Galectin-3, tissue-type activated plasminogen activator, and many more, which lineate the secretion of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, and IL-18) result in severe neuronal loss. Altogether, we emphasized the perspectives of cellular senescence up-regulated by EGFR and its associated membrane receptor molecules in the pathogenesis of AD as a target for a therapeutical alternative to intervene in AD.

Annexin A1 inhibition facilitates NLRP3 inflammasome activation in arsenic-induced insulin resistance in rat liver

Hepatic insulin resistance (IR) is the primary pathology of type 2 diabetes (T2D). The role of the NOD-like receptor protein 3 (NLRP3) inflammasome in arsenic-induced hepatic IR has been previously demonstrated. However, the mechanism of the arsenic-induced activation of the NLRP3 inflammasome is still unclear. Here, we demonstrate that NaAsO₂ downregulated the mRNA and protein level of Annexin A1 (AnxA1), an anti-inflammatory factor, in rat livers and L-02 cells. Moreover, AnxA1 overexpression significantly alleviated arsenic-induced NLRP3 inflammasome activation and IR in L-02 cells. Importantly, Co-immunoprecipitation (Co-IP) results showed that AnxA1 1-190 peptide could bind to the domain encompassing amino acids 1-210 and 211-550 of NLRP3. In conclusion, our experiments demonstrated that arsenic exposure could activate the NLRP3 inflammasome and IR by inhibiting the AnxA1 activity. These findings suggest that AnxA1 may be a promising therapeutic target of arsenicosis.

Tat-NTS Suppresses the Proliferation, Migration and Invasion of Glioblastoma Cells by Inhibiting Annexin-A1 Nuclear Translocation

Prevention of the nuclear translocation of ANXA1 with Tat-NTS was recently reported to alleviate neuronal injury and protect against cerebral stroke. However, the role that Tat-NTS plays in the occurrence and development of gliomas still needs to be elucidated. Therefore, human glioblastoma (GB) cells were treated with various concentrations of Tat-NTS for 24 h, and cell proliferation, migration and invasion were assessed with CCK-8 and Transwell assays. The nuclear translocation of ANXA1 was evaluated by subcellular extraction and immunofluorescence, and protein expression levels were detected by Western blot analysis. In addition, the activity of MMP-2/9 was measured by gelatin zymography. The results revealed that Tat-NTS significantly inhibited the nuclear translocation of ANXA1 in U87 cells and inhibited the proliferation, migration and invasion of GB cells. Tat-NTS also suppressed cell cycle regulatory proteins and MMP-2/-9 activity and expression. Moreover, Tat-NTS reduced the level of p-p65 NF-κB in U87 cells. These results suggest that the Tat-NTS-induced inhibition of GB cell proliferation, migration and invasion is closely associated with the induction of cell cycle arrest, downregulation of MMP-2/-9 expression and activity and suppression of the NF-κB signaling pathway. Thus, Tat-NTS may be a potential chemotherapeutic agent for the treatment of GB.

LncRNA Gm26917 regulates inflammatory response in macrophages by enhancing Annexin A1 ubiquitination in LPS-induced acute liver injury

Long noncoding RNAs (lncRNAs) are defined as transcripts of more than 200 nucleotides that have little or no coding potential. LncRNAs function as key regulators in diverse physiological and pathological processes. However, the roles of lncRNAs in lipopolysaccharide (LPS)-induced acute liver injury (ALI) are still elusive. In this study, we report the roles of lncRNA Gm26917 induced by LPS in modulating liver inflammation. As key components of the innate immune system, macrophages play critical roles in the initiation, progression and resolution of ALI. Our studies demonstrated that Gm26917 localized in the cytoplasm of hepatic macrophages and globally regulated the expression of inflammatory genes and the differentiation of macrophages. In vivo study showed that lentivirus-mediated gene silencing of Gm26917 attenuated liver inflammation and protected mice from LPS-induced ALI. Furthermore, mechanistic study showed that the 3'-truncation of Gm26917 interacted with the N-terminus of Annexin A1, a negative regulator of the NF-κB signaling pathway. We also found that Gm26917 knockdown suppressed NF-κB activity by decreasing the ubiquitination of Annexin A1 and its interaction with NEMO. In addition, expression of Gm26917 in inflammatory macrophages was regulated by the transcription factor forkhead box M1 (FOXM1). LPS treatment dramatically increased the binding of FOXM1 to the promoter region of Gm26917 in macrophages. In summary, our findings suggest that lncRNA Gm26917 silencing protects against LPS-induced liver injury by regulating the TLR4/NF-κB signaling pathway in macrophages.

From NSAIDs to Glucocorticoids and Beyond

Our interest in inflammation and its treatment stems from ancient times. Hippocrates used willow bark to treat inflammation, and many centuries later, salicylic acid and its derivative aspirin's ability to inhibit cyclooxygenase enzymes was discovered. Glucocorticoids (GC) ushered in a new era of treatment for both chronic and acute inflammatory disease, but their potentially dangerous side effects led the pharmaceutical industry to seek other, safer, synthetic GC drugs. The discovery of the GC-inducible endogenous anti-inflammatory protein annexin A1 (AnxA1) and other endogenous proresolving mediators has opened a new era of anti-inflammatory therapy. This review aims to recapitulate the last four decades of research on NSAIDs, GCs, and AnxA1 and their anti-inflammatory effects.

Lycopene improves maternal reproductive performance by modulating milk composition and placental antioxidative and immune status

Placental health and milk quality are important for maternal reproductive performance during pregnancy and lactation. Lycopene plays an important role in antioxidation, anti-inflammation and regulating lipid metabolism. The goal of the present study was to investigate the effects of dietary lycopene supplementation in the pig model on reproductive performance, placental health and milk composition during maternal gestation and lactation. In the present study, the litter size of live piglets was increased and the litter size of dead piglets was decreased by lycopene supplementation of the diet of sows. The litter weight at birth and weaning were increased in the lycopene group. Through placental proteomics, we enriched differentially expressed proteins (DEPs), gene ontology (GO) terms, and Kyoto encyclopedia of proteins and genomes (KEGG) pathways involved in immunity, anti-inflammation, antioxidants, and lipid metabolism and transport. Furthermore, in terms of placental health, we analyzed the levels of related enzymes, metabolites and mRNA expression in the placenta. Lycopene was shown to reduce mRNA expression and the levels of placental inflammatory factors, increase the content of immunoglobulin, improve the antioxidant capacity, and improve lipid metabolism and lipid transport in the placenta. In terms of sow milk composition, lycopene increased the levels of immunoglobulins in colostrum and lactose in colostrum and milk. Overall, the results of the present study demonstrate that dietary lycopene supplementation of sows during gestation and lactation improves the reproductive performance to a certain extent; this may be due to lycopene improving the placental health and milk composition of sows.

Annexin A1 Mimetic Peptide and Piperlongumine: Anti-Inflammatory Profiles in Endotoxin-Induced Uveitis

Uveitis is one of the main causes of blindness worldwide, and therapeutic alternatives are worthy of study. We investigated the effects of piperlongumine (PL) and/or annexin A1 (AnxA1) mimetic peptide Ac2-26 on endotoxin-induced uveitis (EIU). Rats were inoculated with lipopolysaccharide (LPS) and intraperitoneally treated with Ac2-26 (200 µg), PL (200 and 400 µg), or Ac2-26 + PL after 15 min. Then, 24 h after LPS inoculation, leukocytes in aqueous humor, mononuclear cells, AnxA1, formyl peptide receptor (fpr)1, fpr2, and cyclooxygenase (COX)-2 were evaluated in the ocular tissues, along with inflammatory mediators in the blood and macerated supernatant. Decreased leukocyte influx, levels of inflammatory mediators, and COX-2 expression confirmed the anti-inflammatory actions of the peptide and pointed to the protective effects of PL at higher dosage. However, when PL and Ac2-26 were administered in combination, the inflammatory potential was lost. AnxA1 expression was elevated among groups treated with PL or Ac2-26 + PL but reduced after treatment with Ac2-26. Fpr2 expression was increased only in untreated EIU and Ac2-26 groups. The interaction between Ac2-26 and PL negatively affected the anti-inflammatory action of Ac2-26 or PL. We emphasize that the anti-inflammatory effects of PL can be used as a therapeutic strategy to protect against uveitis.

Analysis of the Expression and Prognostic Value of Annexin Family Proteins in Bladder Cancer

Background

Bladder cancer (BC) is the most common tumor of the urinary system. Non-muscle-invasive bladder cancer (NMIBC) has a high recurrence rate after surgery, and patients with muscle-invasive bladder cancer (MIBC) have poor quality of life after radical surgery. Understanding the molecular mechanism of bladder cancer is helpful for providing a more appropriate treatment approach. Annexins are calcium-binding proteins and play an important role in different tumor cells. However, the role of the annexin family in bladder cancer has not been studied in detail.

Methods

ONCOMINE, UALCAN, TIMER2.0, Kaplan-Meier Plotter, cBioPortal, and WebGestalt were utilized in this study.

Results

ANXA2, ANXA3, ANXA4, ANXA8, and ANXA9 were significantly increased in bladder tumor tissues, while ANXA6, ANXA7, and ANXA11 were significantly decreased. ANXA1, ANXA2, ANXA3, ANXA5, ANXA6, ANXA7, and ANXA9 had prognostic value in bladder cancer. In addition, specific annexins were specifically expressed in different subtypes of MIBC and were related to the histological morphology of bladder tumors. ANXA1, ANXA2, ANXA3, ANXA5, ANXA6, ANXA7, and ANXA8 were highly expressed in basal-subtype MIBC, while ANXA4, ANXA9, ANXA10, and ANXA11 were mainly expressed in luminal-subtype MIBC. Finally, we analyzed the possible mechanisms of ANXAs in different subtypes of bladder cancer through GO and KEGG analyses and the correlation between ANXAs and immune infiltration in the tumor microenvironment.

Conclusion

Taken together, our results indicate that annexins might play important roles in BC and have the potential to be used as markers for subtype classification.

Annexin A1 as a Regulator of Immune Response in Cancer

Annexin A1 is a 37 kDa phospholipid-binding protein that is expressed in many tissues and cell types, including leukocytes, lymphocytes and epithelial cells. Although Annexin A1 has been extensively studied for its anti-inflammatory activity, it has been shown that, in the cancer context, its activity switches from anti-inflammatory to pro-inflammatory. Remarkably, Annexin A1 shows pro-invasive and pro-tumoral properties in several cancers either by eliciting autocrine signaling in cancer cells or by inducing a favorable tumor microenvironment. Indeed, the signaling of the N-terminal peptide of AnxA1 has been described to promote the switching of macrophages to the pro-tumoral M2 phenotype. Moreover, AnxA1 has been described to prevent the induction of antigen-specific cytotoxic T cell response and to play an essential role in the induction of regulatory T lymphocytes. In this way, Annexin A1 inhibits the anti-tumor immunity and supports the formation of an immunosuppressed tumor microenvironment that promotes tumor growth and metastasis. For these reasons, in this review we aim to describe the role of Annexin A1 in the establishment of the tumor microenvironment, focusing on the immunosuppressive and immunomodulatory activities of Annexin A1 and on its interaction with the epidermal growth factor receptor.

Role of Annexin A1 in Squamous Cell Lung Cancer Progression

Lung cancer remains the primary cause of cancer-related death worldwide, and its molecular mechanisms of tumor progression need further characterization to improve the clinical management of affected patients. The role of Annexin A1 (ANXA1) in tumorigenesis and cancer progression in general and especially in lung cancer remains to be controversial and seems to be highly tissue specific and inconsistent among tumor initiation, progression, and metastasis. In the current study, we investigated ANXA1 expression in 81 squamous cell lung cancer (SQCLC), 86 pulmonary adenocarcinoma (AC), and 30 small cell lung cancer (SCLC) patient-derived tissue samples and its prognostic impact on patient's survival. Mechanistically, we analyzed the impact of ANXA1 expression on proliferation and migration of SQCLC cell lines using CRISPR-Cas9 and mammalian overexpression vectors. Strong expression of ANXA1 was significantly correlated to longer overall survival only in SQCLC patients (P = 0.019). Overexpression of ANXA1 promoted proliferation in SQCLC cell lines but suppressed their migration, while knockout of ANXA1 promoted cell migration and suppressed proliferation. In conclusion, ANXA1 expression might elongate patients' survival by inhibiting tumor cell migration and subsequent metastasis.

HDX-MS for Epitope Characterization of a Therapeutic ANTIBODY Candidate on the Calcium-Binding Protein Annexin-A1

Annexin-A1 (ANXA1) belongs to a class of highly homologous Ca2+-dependent phospholipid-binding proteins. Its structure consists of a core region composed of four homologous repeats arranged in a compact, hydrolysis-resistant structure and an N-terminal region with a Ca2+-dependent conformation. ANXA1 is involved in several processes, including cell proliferation, apoptosis, metastasis, and the inflammatory response. Therefore, the development of antibodies blocking selected regions on ANXA1 holds great potential for the development of novel therapeutics treating inflammatory and cancer diseases. Here, we report the interaction site between an ANXA1-specific antibody known to inhibit T cell activation without adverse cytotoxic effects and ANXA1 using amide hydrogen-deuterium exchange mass spectrometry (HDX-MS). For the epitope determination, we applied two bottom-up HDX-MS approaches with pepsin digestion in solution and immobilized on beads. Both strategies revealed the interaction region within domain III of ANXA1 in Ca2+-bound conformation. The antibody-binding region correlates with the hydrophobic binding pocket of the N-terminal domain formed in the absence of calcium. This study demonstrates that even cryptic and flexible binding regions can be studied by HDX-MS, allowing a fast and efficient determination of the binding sites of antibodies which will help to define a mode of action profile for their use in therapy.

Knockdown of Annexin-A1 Inhibits Growth, Migration and Invasion of Glioma Cells by Suppressing the PI3K/Akt Signaling Pathway

ANXA1, which can bind phospholipid in a calcium dependent manner, is reported to play a pivotal role in tumor progression. However, the role and mechanism of ANXA1 involved in the occurrence and development of malignant glioma are still not well studied. Therefore, we explored the effects of ANXA1 on normal astrocytes and glioma cell proliferation, apoptosis, migration and invasion and the underlying mechanisms. We found that ANXA1 was markedly up-regulated in glioma cell lines and glioma tissues. Down-regulation of ANXA1 inhibited normal astrocytes and glioma cell proliferation and induced the cell apoptosis, which suggested that the consequences of loss of Annexin 1 are not specific to the tumor cells. Furthermore, the siRNA-ANXA1 treatment significantly reduced tumor growth rate and tumor weight. Moreover, decreasing ANXA1 expression caused G2/M phase arrest by repressing expression levels of cdc25C, cdc2 and cyclin B1. Interestingly, ANXA1 did not affect the expressions of β-catenin, GSK-3β and NF-κB, the key signaling molecules associated with cancer progression. However, siRNA-ANXA1 was found to negatively regulate phosphorylation of AKT and the expression and activity of MMP2/-9. Finally, the decrease of cell proliferation and invasiveness induced by ANXA1 down-regulation was partially reversed by combined treatment with AKT agonist insulin-like growth factor-1 (IGF-1). Meanwhile, the inhibition of glioma cell proliferation and invasiveness induced by ANXA1 down-regulation was further enhanced by combined treatment with AKT inhibitor LY294002. In summary, these findings demonstrate that ANXA1 regulates proliferation, migration and invasion of glioma cells via PI3K/AKT signaling pathway.

Tumor vasculature-targeted 10B delivery by an Annexin A1-binding peptide boosts effects of boron neutron capture therapy

Background

p-Boronophenylalanine (¹⁰BPA) is a powerful ¹⁰B drug used in current clinical trials of BNCT. For BNCT to be successful, a high (500 mg/kg) dose of ¹⁰BPA must be administered over a few hours. Here, we report BNCT efficacy after rapid, ultralow-dose administration of either tumor vasculature-specific annexin A1-targeting IFLLWQR (IF7)-conjugated ¹⁰BPA or borocaptate sodium (¹⁰BSH).

Methods

(1) IF7 conjugates of either ¹⁰B drugs intravenously injected into MBT2 bladder tumor-bearing mice and biodistribution of ¹⁰B in tumors and normal organs analyzed by prompt gamma-ray analysis. (2) Therapeutic effect of IF7-¹⁰B drug-mediated BNCT was assessed by either MBT2 bladder tumor bearing C3H/He mice and YTS-1 tumor bearing nude mice.

Results

Intravenous injection of IF7C conjugates of either ¹⁰B drugs into MBT2 bladder tumor-bearing mice promoted rapid ¹⁰B accumulation in tumor and suppressed tumor growth. Moreover, multiple treatments at ultralow (10–20 mg/kg) doses of IF7-¹⁰B drug-mediated BNCT significantly suppressed tumor growth in a mouse model of human YTS-1 bladder cancer, with increased Anxa1 expression in tumors and infiltration by CD8-positive lymphocytes.

Conclusions

We conclude that IF7 serves as an efficient ¹⁰B delivery vehicle by targeting tumor tissues via the tumor vasculature and could serve as a relevant vehicle for BNCT drugs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-020-07760-x.

MITF functions as a tumor suppressor in non-small cell lung cancer beyond the canonically oncogenic role

Microphthalamia-associated transcription factor (MITF) is a critical mediator in melanocyte differentiation and exerts oncogenic functions in melanoma progression. However, the role of MITF in non-small cell lung cancer (NSCLC) is still unknown. We found that MITF is dominantly expressed in the low-invasive CL1-0 lung adenocarcinoma cells and paired adjacent normal lung tissues. MITF expression is significantly associated with better overall survival and disease-free survival in NSCLC and serves as an independent prognostic marker. Silencing MITF promotes tumor cell migration, invasion and colony formation in lung adenocarcinoma cells. In xenograft mouse model, MITF knockdown enhances metastasis and tumorigenesis, but decreases angiogenesis in the Matrigel plug assay. Whole transcriptome profiling of the landscape of MITF regulation in lung adenocarcinoma indicates that MITF is involved in cell development, cell cycle, inflammation and WNT signaling pathways. Chromatin immunoprecipitation assays revealed that MITF targets the promoters of FZD7, PTGR1 and ANXA1. Moreover, silencing FZD7 reduces the invasiveness that is promoted by silencing MITF. Strikingly, MITF has significantly inverse correlations with the expression of its downstream genes in lung adenocarcinoma. In summary, we demonstrate the suppressive role of MITF in lung cancer progression, which is opposite to the canonical oncogenic function of MITF in melanoma.

Zooming into the Dark Side of Human Annexin-S100 Complexes: Dynamic Alliance of Flexible Partners

Annexins and S100 proteins form two large families of Ca²⁺-binding proteins. They are quite different both structurally and functionally, with S100 proteins being small (10–12 kDa) acidic regulatory proteins from the EF-hand superfamily of Ca²⁺-binding proteins, and with annexins being at least three-fold larger (329 ± 12 versus 98 ± 7 residues) and using non-EF-hand-based mechanism for calcium binding. Members of both families have multiple biological roles, being able to bind to a large cohort of partners and possessing a multitude of functions. Furthermore, annexins and S100 proteins can interact with each other in either a Ca²⁺-dependent or Ca²⁺-independent manner, forming functional annexin-S100 complexes. Such functional polymorphism and binding indiscrimination are rather unexpected, since structural information is available for many annexins and S100 proteins, which therefore are considered as ordered proteins that should follow the classical “one protein–one structure–one function” model. On the other hand, the ability to be engaged in a wide range of interactions with multiple, often unrelated, binding partners and possess multiple functions represent characteristic features of intrinsically disordered proteins (IDPs) and intrinsically disordered protein regions (IDPRs); i.e., functional proteins or protein regions lacking unique tertiary structures. The aim of this paper is to provide an overview of the functional roles of human annexins and S100 proteins, and to use the protein intrinsic disorder perspective to explain their exceptional multifunctionality and binding promiscuity.

Annexin A1 accounts for an anti-inflammatory binding target of sesamin metabolites

Sesamin [(7α,7'α,8α,8'α)-3,4:3',4'-bis(methylenedioxy)-7,9':7',9-diepoxylignane] is a major lignan in sesame seeds. Sesamin is converted to the catechol metabolite, SC1 [(7α,7'α,8α,8'α)-3',4'-methylenedioxy-7,9':7',9-diepoxylignane-3,4-diol] with anti-inflammatory effects after oral administration. However, its molecular target remains unknown. Analysis using high-performance affinity nanobeads led to the identification of annexin A1 (ANX A1) as an SC1-binding protein. SC1 was found to bind to the annexin repeat 3 region of ANX A1 with a high-affinity constant (Kd = 2.77 μmol L^-1). In U937 cells, SC1 exhibited an anti-inflammatory effect dependent on ANX A1. Furthermore, administration of sesamin or SC1 attenuated carbon tetrachloride-induced liver damage in mice and concurrently suppressed inflammatory responses dependent on ANX A1. The mechanism involved SC1-induced ANX A1 phosphorylation at serine 27 that facilitates extracellular ANX A1 release. Consequently, the ANX A1 released into the extracellular space suppressed the production of tumor necrosis factor α. This study demonstrates that ANX A1 acts as a pivotal target of sesamin metabolites to attenuate inflammatory responses.