Annexin A1 Research Articles

SUPPLEMENTARY TABLES AND FIGURES: Bioinformatic analysis of Annexin A1 (ANXA1) protein expression in different types of cancer.

SUPPLEMENTARY TABLES AND FIGURES: Bioinformatic analysis of Annexin A1 (ANXA1) protein expression in different types of cancer.

Interplay of membrane crosslinking and curvature induction by annexins

Efficient plasma membrane repair (PMR) is required to repair damage sustained in the cellular life cycle. The annexin family of proteins, involved in PMR, are activated by Ca2+ influx from extracellular media at the site of injury. Mechanistic studies of the annexins have been overwhelmingly performed using a single annexin, despite the recruitment of multiple annexins to membrane damage sites in living cells. Hence, we investigate the effect of the presence of the crosslinking annexins, annexin A1, A2 and A6 (ANXA1, ANXA2 and ANXA6) on the membrane curvature induction of annexin A4 (ANXA4) in model membrane systems. Our data support a mechanistic model of PMR where ANXA4 induced membrane curvature and ANXA6 crosslinking promotes wound closure. The model now can be expanded to include ANXA1 and ANXA2 as specialist free edge membrane crosslinkers that act in concert with ANXA4 induced curvature and ANXA6 crosslinking.

Annexin A1 (Ac2-26)-dependent Fpr2 receptor alleviates sepsis-induced acute kidney injury by inhibiting inflammation and apoptosis in vivo and in vitro

ObjectivesExcessive inflammatory responses and apoptosis are critical pathologies that contribute to sepsis-induced acute kidney injury (SI-AKI). Annexin A1 (ANXA1), a member of the calcium-dependent phospholipid-binding protein family, protects against SI-AKI through its anti-inflammatory and antiapoptotic effects, but the underlying mechanisms are still largely unknown.MethodsIn vivo, SI-AKI mouse models were established via caecal ligation and puncture (CLP) and were then treated with the Ac2-26 peptide of ANXA1 (ANXA1 (Ac2-26)), WRW4 (Fpr2 antagonist) or both. In vitro, HK-2 cells were induced by lipopolysaccharide (LPS) and then treated with ANXA1 (Ac2-26), Fpr2–siRNA or both.ResultsIn the present study, we found that the expression levels of ANXA1 were decreased, and the expression levels of TNF-α, IL-1β, IL-6, cleaved caspase-3, cleaved caspase-8 and Bax were significantly increased, accompanied by marked kidney tissue apoptosis in vivo. Moreover, we observed that ANXA1 (Ac2-26) significantly reduced the levels of TNF-α, IL-1β and IL-6 and cleaved caspase-3, cleaved caspase-8, FADD and Bax and inhibited apoptosis in kidney tissue and HK-2 cells, accompanied by pathological damage to kidney tissue. Seven-day survival, kidney function and cell viability were significantly improved in vivo and in vitro, respectively. Furthermore, the administration of ANXA1 (Ac2-26) inhibited the CLP- or LPS-induced phosphorylation of PI3K and AKT and downregulated the level of NF-κB in vivo and in vitro. Moreover, our data demonstrate that blocking the Fpr2 receptor by the administration of WRW4 or Fpr2–siRNA reversed the abovementioned regulatory role of ANXA1, accompanied by enhanced phosphorylation of PI3K and AKT and upregulation of the level of NF-κB in vivo and in vitro.ConclusionsTaken together, this study provides evidence that the protective effect of ANXA1 (Ac2-26) on SI-AKI largely depends on the negative regulation of inflammation and apoptosis via the Fpr2 receptor.

Annexin A2 modulates phospholipid membrane composition upstream of Arp2 to control angiogenic sprout initiation.

The intersection of protein and lipid biology is of growing importance for understanding how cells address structural challenges during adhesion and migration. While protein complexes engaged with the cytoskeleton play a vital role, support from the phospholipid membrane is crucial for directing localization and assembly of key protein complexes. During angiogenesis, dramatic cellular remodeling is necessary for endothelial cells to shift from a stable monolayer to invasive structures. However, the molecular dynamics between lipids and proteins during endothelial invasion are not defined. Here, we utilized cell culture, immunofluorescence, and lipidomic analyses to identify a novel role for the membrane binding protein Annexin A2 (ANXA2) in modulating the composition of specific membrane lipids necessary for cortical F-actin organization and adherens junction stabilization. In the absence of ANXA2, there is disorganized cortical F-actin, reduced junctional Arp2, excess sprout initiation, and ultimately failed sprout maturation. Furthermore, we observed reduced filipin III labeling of membrane cholesterol in cells with reduced ANXA2, suggesting there is an alteration in phospholipid membrane dynamics. Lipidomic analyses revealed that 42 lipid species were altered with loss of ANXA2, including an accumulation of phosphatidylcholine (16:0_16:0). We found that supplementation of phosphatidylcholine (16:0_16:0) in wild-type endothelial cells mimicked the ANXA2 knock-down phenotype, indicating that ANXA2 regulated the phospholipid membrane upstream of Arp2 recruitment and organization of cortical F-actin. Altogether, these data indicate a novel role for ANXA2 in coordinating events at endothelial junctions needed to initiate sprouting and show that proper lipid modulation is a critical component of these events.

Annexin A1 Is Associated with Adverse Clinical Outcomes in Patients with COVID-19.

Severe coronavirus disease 2019 (COVID-19) is characterized by hyperinflammation, vascular damage, and hypercoagulability. Insufficient responses of Annexin A1 (AnxA1), a pro-resolving inhibitor of neutrophil infiltration and activation, might contribute to a severe course of the disease. We longitudinally evaluated AnxA1's role in terms of inflammation, vascular damage, and clinical outcomes in a large prospective cohort of patients with COVID-19. AnxA1 was measured at presentation and during follow-up in the sera of 220 consecutive patients who presented at our hospital during the first wave. AnxA1 was significantly higher in the moderate and severe cases of COVID-19 compared to the healthy controls. Elevated AnxA1 was associated with markers of inflammation and endothelial damage. AnxA1 was significantly higher in patients with thrombotic events and ICU admission. Multivariable logistic regression indicated baseline AnxA1 (per ten units) as a predictor of thrombotic events. Linear mixed models predicted that AnxA1 tended to increase more steeply over time in patients without adverse events, with a statistically significant rise in patients without thrombotic events. These findings might reflect an insufficient increase in AnxA1 as a response to the excessive hyperinflammation in COVID-19. Future studies should evaluate whether hyperinflammation could be reduced through the administration of human recombinant AnxA1 or Ac2-26 peptide.

Sirtuin 5 aggravates microglia-induced neuroinflammation following ischaemic stroke by modulating the desuccinylation of Annexin-A1

BackgroundMicroglia-induced excessive neuroinflammation plays a crucial role in the pathophysiology of multiple neurological diseases, such as ischaemic stroke. Controlling inflammatory responses is considered a promising therapeutic approach. Sirtuin 5 (SIRT5) mediates lysine desuccinylation, which is involved in various critical biological processes, but its role in ischaemic stroke remains poorly understood. This research systematically explored the function and potential mechanism of SIRT5 in microglia-induced neuroinflammation in ischaemic stroke.MethodsMice subjected to middle cerebral artery occlusion were established as the animal model, and primary cultured microglia treated with oxygen–glucose deprivation and reperfusion were established as the cell model of ischaemic stroke. SIRT5 short hairpin RNA, adenovirus and adeno-associated virus techniques were employed to modulate SIRT5 expression in microglia both in vitro and in vivo. Coimmunoprecipitation, western blot and quantitative real-time PCR assays were performed to reveal the molecular mechanism.ResultsIn the current study, we showed that SIRT5 expression in microglia was increased in the early phase of ischaemic stroke. SIRT5 interacts with and desuccinylates Annexin A1 (ANXA1) at K166, which in turn decreases its SUMOylation level. Notably, the desuccinylation of ANXA1 blocks its membrane recruitment and extracellular secretion, resulting in the hyperactivation of microglia and excessive expression of proinflammatory cytokines and chemokines, ultimately leading to neuronal cell damage after ischaemic stroke. Further investigation showed that microglia-specific forced overexpression of SIRT5 worsened ischaemic brain injury, whereas downregulation of SIRT5 exhibited neuroprotective and cognitive-preserving effects against ischaemic brain injury, as proven by the decreased infarct area, reduced neurological deficit scores, and improved cognitive function.ConclusionsCollectively, these data identify SIRT5 as a novel regulator of microglia-induced neuroinflammation and neuronal damage after cerebral ischaemia. Interventions targeting SIRT5 expression may represent a potential therapeutic target for ischaemic stroke.

Proteomic Portrait of Human Lymphoma Reveals Protein Molecular Fingerprint of Disease Specific Subtypes and Progression.

The online version contains supplementary material available at 10.1007/s43657-022-00075-w.

Multi-omics analyses identify molecular signatures with prognostic values in different heart failure aetiologies

BackgroundHeart failure (HF) is the leading cause of morbidity and mortality worldwide, and there is an urgent need for more global studies and data mining approaches to uncover its underlying mechanisms. Multiple omics techniques provide a more holistic molecular perspective to study pathophysiological events involved in the development of HF. MethodsIn this study, we used a label-free whole myocardium multi-omics characterization from three commonly used mouse HF models: transverse aortic constriction (TAC), myocardial infarction (MI), and homozygous Phospholamban-R14del (PLN-R14Δ/Δ). Genes, proteins, and metabolites were analysed for differential expression between each group and a corresponding control group. The core transcriptome and proteome datasets were used for enrichment analysis. For genes that were upregulated at both the RNA and protein levels in all models, clinical validation was performed by means of plasma level determination in patients with HF from the BIOSTAT-CHF cohort. ResultsCell death and tissue repair-related pathways were upregulated in all preclinical models. Fatty acid oxidation, ATP metabolism, and Energy derivation processes were downregulated in all investigated HF aetiologies. Putrescine, a metabolite known for its role in cell survival and apoptosis, demonstrated a 4.9-fold (p < 0.02) increase in PLN-R14Δ/Δ, 2.7-fold (p < 0.005) increase in TAC mice, and 2.2-fold (p < 0.02) increase in MI mice. Four Biomarkers were associated with all-cause mortality (PRELP: Hazard ratio (95% confidence interval) 1.79(1.35, 2.39), p < 0.001; CKAP4: 1.38(1.21, 1.57), p < 0.001; S100A11: 1.37(1.13, 1.65), p = 0.001; Annexin A1 (ANXA1): 1.16(1.04, 1.29) p = 0.01), and three biomarkers were associated with HF-Related Rehospitalization, (PRELP: 1.88(1.4, 2.53), p < 0.001; CSTB: 1.15(1.05, 1.27), p = 0.003; CKAP4: 1.18(1.02, 1.35), P = 0.023). ConclusionsCell death and tissue repair pathways were significantly upregulated, and ATP and energy derivation processes were significantly downregulated in all models. Common pathways and biomarkers with potential clinical and prognostic associations merit further investigation to develop optimal management and therapeutic strategies for all HF aetiologies.

Cholinergic drug downregulates annexin A3 in platelets of Alzheimer’s Disease patients

AbstractBackgroundInvestigation of the expression of annexin A3 (ANXA3) platelets of Alzheimer´s Disease patients pre and post three‐month treatment with cholinesterase inhibitors and compared to healthy controls.MethodThe sample consisted of healthy controls (n=24) and AD drug‐naïve patients (n=34), diagnosed according to DSM‐IV and specificized according to NINCDS‐ADRDA diagnostic criteria. After three months of treatment with cholinesterase inhibitors, platelets were extracted from blood samples of the same AD patients (n=34). The Cambridge cognitive test (CAMCOG) was used as a measure of global cognitive performance, however, scores on both tests were not used to establish the patients' diagnosis. The method of Western Blotting sample analysis was performed through primary antibodies against ANXA3 and secondary antibody, anti‐rabbit IgG‐HRP peroxidase. Student's t‐test or Mann‐Whitney, Pearson's Chi‐square tests were used for numerical variables, Kolmogorov‐Smirnov test were used to analyze a normal distribution and Wilcoxon test to longitudinal variables. Spearman’s rank correlation coefficient was performed for association between ANXA3 levels and clinical parameters.ResultThere was no difference in ANXA3 expression between AD patients before treatment and healthy controls (p=0.926). However, after three months with anticholinergic treatment the AD patients present a decrease in ANXA3 expressions (p=0.012).ConclusionANXA3 levels on platelets samples of patients diagnosed with AD decrease before an evident improvement of the clinical manifestation of the disease.

Annexin A6 Polymorphism Is Associated with Pro-atherogenic Lipid Profiles and with the Downregulation of Methotrexate on Anti-Atherogenic Lipid Profiles in Psoriasis.

Annexin A6 (AnxA6) is a lipid-binding protein that regulates cholesterol homeostasis and secretory pathways. However, the correlation of AnxA6 polymorphism with lipometabolism has never been studied in psoriasis. To investigate the impact of AnxA6 polymorphism on lipid profiles and the expression of AnxA6 protein in both peripheral blood mononuclear cells (PBMCs) and lipometabolism in psoriasis. A total of 265 psoriatic patients received methotrexate (MTX) treatment for 12 weeks, after which their lipid profiles were determined by measuring total cholesterol (TC), triglycerides (TGs), lipoprotein (a) [LP(a)], high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein (LDL), apolipoprotein (a)1 (ApoA1), and apolipoprotein B (ApoB). In addition, AnxA6 (rs11960458) was genotyped in 262 patients and the expression of AnxA6 in PBMCs was measured by Western blotting at baseline and week 8 post-MTX treatment. The CC genotype carriers of rs11960458 had a lower expression of AnxA6 and lower levels of the pro-atherogenic lipids TC, LDL, and ApoB compared to TC genotype carriers. MTX significantly downregulated the levels of the anti-atherogenic lipids HDL-C and ApoA1 and the level of AnxA6 in TC genotype carriers, as well as the level of TGs in CC genotype carriers. The polymorphism of AnxA6, rs11960458, was statistically associated with the levels of pro-atherogenic lipids and with the downregulation of MTX on the levels of anti-atherogenic lipids and TGs in psoriasis.

Proteomic profiling of cell line-derived extracellular vesicles to identify candidate circulatory markers for detection of gallbladder cancer.

Gallbladder cancer (GBC) is the sixth most common gastrointestinal tract cancer with a very low overall survival and poor prognosis. Profiling of cancer-derived extracellular vesicles (EVs) is an emerging strategy for identification of candidate biomarkers for the detection and prognosis of the disease. The aim of the study was to analyse the protein content from GBC cell line- derived EVs with emphasis on proteins which could be used as candidate biomarkers for the detection of GBC. NOZ and OCUG-1 cell lines were cultured and EVs were isolated from conditioned media. LC-MS/MS analysis of total EV proteins led to the identification of a total of 268 proteins in both the cell lines. Of these, 110 proteins were identified with ≥2 unique peptides with ≥2 PSMs in at least two experimental and technical replicate runs. STRING (Search Tool for the Retrieval of Interacting Genes/Proteins) database was used to perform bioinformatics analysis of 110 proteins which showed 'cell adhesion molecule binding', 'integrin binding', 'cadherin binding' among the top molecular functions and 'focal adhesion' to be among the top pathways associated with the EV proteins. A total of 42 proteins including haptoglobin (HP), pyruvate kinase (PKM), annexin A2 (ANXA2), thrombospondin 1 (THBS1), were reported to be differentially abundant in GBC tissue. Of these, 16 proteins were reported to be differentially abundant in plasma and plasma-derived EVs. We infer these proteins to be highly important to be considered as potential circulatory biomarkers for the detection of GBC. To check the validity of this hypothesis, one of the proteins, haptoglobin (HP) as a representative case, was analysed in plasma by quantitative Enzyme- linked immunosorbent assay (ELISA) and we observed its increased levels in GBC in comparison to controls (p value= 0.0063). Receiver operating characteristic (ROC) curve analysis for GBC vs controls showed an Area under the ROC Curve (AUC) of 0.8264 for HP with 22% sensitivity against 100% specificity. We propose that HP along with other candidate proteins may be further explored for their clinical application.

Hypoxia-induced circADAMTS6 in a TDP43-dependent manner accelerates glioblastoma progression via ANXA2/ NF-κB pathway.

Circular RNAs (circRNAs) play important roles in the malignant progression of tumours. Herein, we identified an unreported circRNA (hsa-circ-0072688, also named circADAMTS6) that is specifically upregulated in the hypoxic microenvironment of glioblastoma and closely correlated with poor prognosis of gliblastoma patients. We found that circADAMTS6 promotes the malignant progression of glioblastoma by promoting cell proliferation and inhibiting apoptosis. Mechanistically, the hypoxic tumour microenvironment upregulates circADAMTS6 expression through transcription factor activator protein 1 (AP-1) and RNA-binding protein TAR DNA-binding protein 43 (TDP43). Moreover, circADAMTS6 accelerates glioblastoma progression by recruiting and stabilising annexin A2 (ANXA2) in a proteasomes-dependent manner. Furthermore, we found T-5224 (AP-1 inhibitor) treatment induces downregulation of circADAMTS6 and then inhibits tumour growth. In conclusion, our findings highlight the important role of the circADAMTS6/ANXA2 axis based on hypoxic microenvironment in glioblastoma progression, as well as its regulation in NF-κB pathway. Targeting circADAMTS6 is thus expected to become a novel therapeutic strategy for glioblastoma.

Development of Annexin A1-surface-functionalized metal-complex multi-wall lipid core nanocapsules and effectiveness on experimental colitis

Annexin A1 (AnxA1), a 37KDa protein, is secreted by inflammatory and epithelial cells and displays anti-inflammatory and wound healing activities in intestinal bowel diseases. Herein, we aimed to functionalize recombinant AnxA1 (AnxA1) on multi-wall lipid core nanocapsules (MLNC) and investigate its effectiveness on experimental colitis. MLNC were prepared by covering lipid core nanocapsules (LNC) with chitosan, which coordinates metals to specific protein chemisorption sites. Therefore, MLNC were linked to Zn2+ and AnxA1 was added to form MLNC-AnxA1. LNC, MLNC and MLNC-AnxA1 presented average size of 129, 152 and 163 nm, respectively, and similar polydispersity indexes (0.xx); incorporation of chitosan inverted the negative potential zeta; the coordination efficiency of AnxA1 was 92.22 %, and transmission electron microscope photomicrograph showed MLNC-AnxA1 had a spherical shape. The effectiveness of MLNC-AnxA1 was measured in Dextran Sulfate Sodium (DSS)-induced colitis in male C57BL/6 mice. DSS (2 % solution) was administered from days 1–6; saline, LNC, MLNC, MLNC-AnxA1 or AnxA1 were administered, once a day, by oral or intraperitoneal (i.p.) routes, from days 6–9. Clinical parameters of the disease were measured from day 0–10 and gut tissues were collected for histopathology, immunohistochemistry and flow cytometry analyses. Only i.p. treatment with MLNC-AnxA1 reduced weight loss, diarrhea and disease activity index, and prevented loss of colonic structure integrity; induced the switch of macrophages into M2 phenotype in the lamina propria; recovered the colonic histoarchitecture by decreasing dysplasia of crypts, inflammation and ulcerations; restored the expression of claudin-1 Zonna-occludens-1 tight junctions in the inflamed gut; and induced stem cell proliferation in intestinal crypts. Associated, data highlight the functionalization of MLNC with AnxA1 as a tool to improve the local actions of such protein in the inflamed gut by inducing resolution of inflammation and tissue repair.

The p-STAT3/ANXA2 axis promotes caspase-1-mediated hepatocyte pyroptosis in non-alcoholic steatohepatitis

BackgroundTo explore the roles of Annexin A2 (ANXA2) on hepatocyte pyroptosis and hepatic fibrosis in nonalcoholic steatohepatitis (NASH) and underlying molecular mechanism.MethodsBioinformatics analyses were performed on transcriptome data of liver tissues from mice and patients with liver fibrosis for screening the hepatocyte pyroptosis-related differential genes. The in vivo NASH mouse model and in vitro NASH cellular model were established. The expression levels of Anxa2/ANXA2 were quantified. Then, the upstream transcription factor of Anxa2 was screened by ChIP-Seq and experimentally verified. The effects of the p-STAT3/ANXA2 axis on Caspase-1 mediated pyroptosis and fibrosis were explored by in vivo and in vitro experiments.ResultsBioinformatics analyses suggested that the expression of Anxa2/ANXA2 was significantly up-regulated in liver tissues of both NASH mice and patients scoring with high pyroptotic activity. Experimental data showed that the ANXA2 expression was positively associated with the development of hepatocyte pyroptosis and fibrosis. As a transcription factor of ANXA2, p-STAT3 can bind to the promoter of Anxa2 and promote its transcription. The inhibition of p-STAT3 can significantly suppress hepatocyte pyroptosis and fibrosis, which was significantly reversed after the over-expression of Anxa2. Caspase-1 was verified as the player of the p-STAT3/ANXA2 axis to promote pyroptosis and fibrosis. By specifically inhibiting Caspase-1, the promotion effect of the p-STAT3/ANXA2 axis on pyroptosis and fibrosis can be significantly weakened.ConclusionThe p-STAT3 promoted Anxa2 expression at the transcription level, thus activating the Caspase-1 mediated hepatocyte pyroptosis and fibrosis in NASH.

Strong Annexin A10 Expression Supports a Pancreatic Primary and Combined Annexin A10, Claudin 18, and SOX2 Expression Supports an Esophagogastric Origin in Carcinomas of Unknown Primary.

Primary tumor site determination for gastrointestinal (GI) tract and pancreaticobiliary (PB) tree carcinomas that present as metastasis of unknown primary can be problematic. Annexin A10 (ANXA10), claudin 18 (CLDN18), and trefoil factor 1 (TFF1) have been identified through expression profiling as markers of gastric lineage commitment; sex-determining region Y (SRY)-box transcription factor 2 (SOX2) expression has been reported in several tumor types, including gastric adenocarcinomas. We evaluated the diagnostic utility of immunohistochemistry for ANXA10, CLDN18, SOX2, and TFF1 for determining the site of origin for GI/PB adenocarcinomas. Immunohistochemistry for all 4 markers was performed on tissue microarrays including 559 GI/PB tumors and 421 other tumors. H-scores were calculated as the product of the intensity (0 to 3) and extent (percentage, 0% to 100%) of staining. Positive staining was defined as >5% staining. ANXA10 expression was most frequent in pancreatic adenocarcinomas when compared with all other GI/PB tumors (96.4% vs. 43.5%, P <0.001). Strong staining for ANXA10 (H-score ≥200) distinguished pancreatic ductal adenocarcinoma from intrahepatic cholangiocarcinoma and adenocarcinomas of the gallbladder and colorectum (69.6% vs. 0%, P <0.001). Triple positivity for ANXA10, CLDN18, and SOX2 was more frequent in esophagogastric tumors than in other GI/PB tumors (22.6% vs. 4.1%; P <0.001). TFF1 expression was observed in nearly all tumor types. Staining for ANXA10, CLDN18, and SOX2 as part of a panel may aid in distinguishing esophagogastric adenocarcinomas from lower GI/PB tumors. ANXA10 staining may be particularly useful in distinguishing pancreatic adenocarcinomas from intrahepatic cholangiocarcinoma and adenocarcinomas of the gallbladder and colorectum.

Apigenin Modulates AnxA6- and TNAP-Mediated Osteoblast Mineralization.

Mineralization-competent cells like osteoblasts and chondrocytes release matrix vesicles (MVs) which accumulate Ca2+ and Pi, creating an optimal environment for apatite formation. The mineralization process requires the involvement of proteins, such as annexins (Anx) and tissue-nonspecific alkaline phosphatase (TNAP), as well as low molecular-weight compounds. Apigenin, a flavonoid compound, has been reported to affect bone metabolism, but there are doubts about its mechanism of action under physiological and pathological conditions. In this report, apigenin potency to modulate annexin A6 (AnxA6)- and TNAP-mediated osteoblast mineralization was explored using three cell lines: human fetal osteoblastic hFOB 1.19, human osteosarcoma Saos-2, and human coronary artery smooth muscle cells HCASMC. We compared the mineralization competence, the morphology and composition of minerals, and the protein distribution in control and apigenin-treated cells and vesicles. The mineralization ability was monitored by AR-S/CPC analysis, and TNAP activity was determined by ELISA assay. Apigenin affected the mineral structure and modulated TNAP activity depending on the concentration. We also observed increased mineralization in Saos-2 cells. Based on TEM-EDX, we found that apigenin influenced the mineral composition. This flavonoid also disturbed the intracellular distribution of AnxA6 and TNAP, especially blocking AnxA6 aggregation and TNAP attachment to the membrane, as examined by FM analysis of cells and TEM-gold analysis of vesicles. In summary, apigenin modulates the mineralization process by regulating AnxA6 and TNAP, as well as through various effects on normal and cancer bone tissues or atherosclerotic soft tissue.

Annexin A2 plays a key role in protecting against cisplatin-induced AKI through β-catenin/TFEB pathway

Acute kidney injury (AKI) is in high prevalence in the world. However, the therapeutic strategies for AKI are still in mystery. Studies have shown to improve autophagy and lysosomal function could inhibit AKI. But their modulators need to be explored in detail. Annexin A2 (ANXA2) is a phospholipid-binding protein involving in organelle membrane integrity function, suggesting its important role in autophagy and lysosome homeostasis. It implicates ANXA2 potentially protects against AKI. However, this has not been elucidated. Herein, we found that ANXA2 is increased in renal tubules in cisplatin-induced AKI mice. Ectopic expression of ANXA2 improved lysosomal functions and enhanced autophagic flux, further protecting against renal tubular cell apoptosis and kidney injury. Conversely, knockdown of ANXA2 inhibited lysosomal function and autophagy, which aggravated the progression of AKI. Transcriptome sequencing revealed β-catenin signaling is highly responsible for this process. In vitro, we found ANXA2 induced β-catenin activation, further triggering T-cell factor-4 (TCF4)-induced transcription factor EB (TFEB). Furthermore, TFEB promoted lysosome biogenesis to enhance autophagic flux, resulting in the alleviation of AKI. Our new findings underline ANXA2 is a new therapeutic potential for AKI through modulating autophagy and lysosomal function. The underlying mechanism is associated with its inductive effects on β-catenin/TFEB pathway.

Annexin A1 upregulates hematoma resolution via the FPR2/p-ERK(1/2)/DUSP1/CD36 signaling pathway after germinal matrix hemorrhage

Germinal matrix hemorrhage (GMH) is one of the leading causes of morbidity and mortality in preterm infants in the United States, with little progress made in its clinical management. Blood clots disrupting normal cerebrospinal fluid circulation and absorption after germinal matrix hemorrhage are key contributors towards post-hemorrhagic hydrocephalus development. n-formyl peptide receptor 2 (FPR2), a G-protein-coupled receptor, has been associated with the activation of p-ERK1/2, which in turn promotes the transcription of the DUSP1 gene, which may play a role in CD36 signaling. CD36 scavenger, a transmembrane glycoprotein, plays an essential role in microglia phagocytic blood clot clearance after GMH. FPR2's role in blood clot clearance after hemorrhagic stroke is unknown. We hypothesize that FPR2 activation by FPR2 agonist Annexin A1 (AnxA1) will enhance hematoma resolution via the upregulation of the CD36 signaling pathway, thereby improving short- and long-term neurological outcomes. Bacterial collagenase (0.3 U) was infused intraparenchymally into the right hemispheric ganglionic eminence in P7 rat pups to induce GMH. AnxA1 and FPR2 Inhibitor (Boc2) were given at 1-h post-GMH via intranasal administration. FPR2 CRISPR was given 48-h prior to GMH induction. Short-term neurological deficits were assessed using negative geotaxis test. Hematoma volume was assessed using hemoglobin assay. Protein expression was assessed using western blots. Long-term neurocognitive deficits and motor coordination were assessed using Morris water maze, rotarod, and foot fault tests. We have demonstrated that AnxA1 treatment enhances hematoma resolution and improved short and long-term outcomes. Lastly, FPR2 agonist AnxA1 treatment resulted in the upregulation of the FPR2/p-ERK(1/2)/DUSP1/CD36 signaling pathway.

Annexin A2 Improves the Osteogenic Differentiation of Mesenchymal Stem Cells Exposed to High-Glucose Conditions through Lessening the Senescence.

Osteoporosis is frequently found in chronic diabetic patients, and it results in an increased risk of bone fractures occurring. The underlying mechanism of osteoporosis in diabetic patients is still largely unknown. Annexin A2 (ANXA2), a family of calcium-binding proteins, has been reported to be involved in many biological process including bone remodeling. This study aimed to investigate the role of ANXA2 in mesenchymal stem cells (MSCs) during in vitro osteoinduction under high-glucose concentrations. Osteogenic gene expression, calcium deposition, and cellular senescence were determined. The high-glucose conditions reduced the osteogenic differentiation potential of the MSCs along with the lower expression of ANXA2. Moreover, the high-glucose conditions increased the cellular senescence of the MSCs as determined by senescence-associated β-galactosidase staining and the expression of p16, p21, and p53 genes. The addition of recombinant ANXA2 could recover the glucose-induced deterioration of the osteogenic differentiation of the MSCs and ameliorate the glucose-induced cellular senescence of the MSCs. A Western blot analysis revealed an increase in p53 and phosphorylated p53 (Ser 15), which was decreased by recombinant ANXA2 in MSC osteoblastic differentiation under high-glucose conditions. Our study suggested that the alteration of ANXA2 in high-glucose conditions may be one of the plausible factors in the deterioration of bones in diabetic patients by triggering cellular senescence.

Annexin A1 mimetic peptide Ac2-26 alleviates renal inflammatory injury in a diabetic mice model through the suppression of p38MAPK/NF-κB

Purpose: To examine the protective effect of mimetic peptide Ac2-26 of Annexin A1 (ANXA1) against renal inflammatory injury in a diabetic mice model.&#x0D; Methods: Twenty-four mice were randomized into three groups with eight mice per group. These included control group (CG), model group (MG) given intraperitoneal injection of streptozotocin (60 mg/kg), and AC2-26 group (AG) given AC2-26, 72 h after the induction of diabetes. Fasting blood glucose (FBG), blood lipids, and renal function in the mice were determined by Sysmex-180 Biochemistry Analyzer, while serum inflammatory factors in renal tissue were also determined.&#x0D; Results: Compared with the model group, there was a significant decrease in the levels of FBG, triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), oxidized LDL (ox-LDL), as well as in 24 h urinary protein, creatinine (Cr) and blood urea nitrogen (BUN), but a significant increase in body weight in AC2-26 group (p &lt; 0.001). There was a significant decrease in TNF-α, IL-6, IL-1β, and IL-18 levels, as well as in mRNA levels and protein expressions of p38MAPK, NF-κBP6, ANXA1 in AC2-26 group when compared with the model group (p &lt; 0.001).&#x0D; Conclusion: Annexin A1 is the target gene of p38MAPK. Annexin A1 mimetic peptide Ac2-26 alleviates renal inflammation by suppressing p38MAPK/NF-κB pathway, thus improving renal function in the diabetic mice model. Hence, the findings of this study provide a potential avenue for the development of an effective treatment for renal disease in diabetics.