Long noncoding RNA VPS9D1-AS1 promotes the progression of endometrial cancer via regulation of the miR-187-3p/S100A4 axis.

VPS9D1-AS1 functions as an oncogene in many cancers. However, its role and potential mechanism in the progression of endometrial cancer (EC) are not fully understood. VPS9D1-AS1 levels in EC and adjacent normal tissues were investigated using the TCGA-UCEC cohort and 24 paired clinical samples. The roles of VPS9D1-AS1 and miR-187-3p in cell cycle, proliferation, and apoptosis were evaluated by loss- and gain-of-function experiments. In addition, the effect of VPS9D1-AS1 on tumor growth was further investigated in vivo. Rescue experiments were performed to investigate the involvement of the miR-187-3p/S100A4 axis in VPS9D1-AS1 knockdown-mediated antitumor effects. VPS9D1-AS1 was highly expressed in EC tissues. VPS9D1-AS1 knockdown, similar to miR-187-3p overexpression, significantly inhibited cell proliferation, inhibited colony formation, induced cell cycle arrest, and facilitated apoptosis of KLE cells. MiR-187-3p bound directly to VPS9D1-AS1 and the 3'UTR of S100A4. Furthermore, VPS9D1-AS1 negatively regulated miR-187-3p while positively regulating S100A4 expression in EC cells. MiR-187-3p knockdown or S100A4 overexpression partially reversed the tumor suppressive function of VPS9D1-AS1 knockdown. The results suggest that VPS9D1-AS1 affects EC progression by regulating the miR-187-3p/S100A4 axis. This may provide a promising therapeutic target to help treat EC.

Versican maintains the homeostasis of adipose tissues and regulates energy metabolism.

Versican is a large chondroitin sulfate proteoglycan in the extracellular matrix. It plays a pivotal role in the formation of the provisional matrix. S100a4, previously known as fibroblast-specific protein, functions as a calcium channel-binding protein. To investigate the role of versican expressed in fibroblasts, we generated conditional knockout mice in which versican expression is deleted in cells expressing S100a4. We found that S100a4 is expressed in adipose tissues, and these mice exhibit obesity under a normal diet, which becomes apparent as early as five months. The white adipose tissues of these mice exhibited decreased expression levels of S100a4 and versican and hypertrophy of adipocytes. qRT-PCR showed a reduced level of UCP1 in their white adipose tissues, indicating that the basic energy metabolism is diminished. These results suggest that versican in adipose tissues maintains the homeostasis of adipose tissues and regulates energy metabolism.

Mts1 (S100A4) and Its Peptide Demonstrate Cytotoxic Activity in Complex with Tag7 (PGLYRP1) Peptide.

Receptors of cytokines are major regulators of the immune response. In this work, we have discovered two new ligands that can activate the TNFR1 (tumor necrosis factor receptor 1) receptor. Earlier, we found that the peptide of the Tag (PGLYRP1) protein designated 17.1 can interact with the TNFR1 receptor. Here, we have found that the Mts1 (S100A4) protein interacts with this peptide with a high affinity (Kd = 1.28 × 10-8 M), and that this complex is cytotoxic to cancer cells that have the TNFR1 receptor on their surface. This complex induces both apoptosis and necroptosis in cancer cells with the involvement of mitochondria and lysosomes in cell death signal transduction. Moreover, we have succeeded in locating the Mts1 fragment that is responsible for protein-peptide interaction, which highly specifically interacts with the Tag7 protein (Kd = 2.96 nM). The isolated Mts1 peptide M7 also forms a complex with 17.1, and this peptide-peptide complex also induces the TNFR1 receptor-dependent cell death. Molecular docking and molecular dynamics experiments show the amino acids involved in peptide binding and that may be used for peptidomimetics' development. Thus, two new cytotoxic complexes were created that were able to induce the death of tumor cells via the TNFR1 receptor. These results may be used in therapy for both cancer and autoimmune diseases.

GnRH-mediated suppression of S100A4 expression inhibits endometrial epithelial cell proliferation in sheep via GNAI2/MAPK signaling.

Background: Gonadotrophin-releasing hormone (GnRH) administration significantly decreases the pregnancy rate of recipient ewes after embryo transfer, possibly because GnRH affects endometrial epithelial cell function. Therefore, this study investigated the effect of GnRH on endometrial epithelial cells. Methods: Transcriptome sequencing was used to determine the regulatory effect of GnRH on the ewe endometrium, and the S100A4 gene, which showed altered transcription, was screened as a candidate regulator of this effect. Endometrial epithelial cells were further isolated, the S100A4 protein was immunoprecipitated, and host proteins that interacted with S100A4 were identified by mass spectrometry. We further verified the effects of S100A4 and GNAI2 on the proliferation of endometrial epithelial cells via overexpression/knockdown experiments and subsequent CCK-8 and EdU assays. The effect of S100A4 deletion in endometrial cells on reproduction was verified in mice with S100A4 knockout. Results: Our results showed that S100A4 gene transcription in endometrial cells was significantly inhibited after GnRH administration. GNAI2 was identified as a downstream interacting protein of S100A4, and S100A4 was confirmed to activate the MAPK signaling pathway to promote cell proliferation by targeting GNAI2. Conclusion: GnRH can suppress the expression of S100A4 in the endometrium, consequently inhibiting the proliferation of endometrial cells through the S100A4/GNAI2/MAPK signaling pathway. These findings suggest a potential explanation for the limited efficacy of GnRH in promoting embryo implantation.

Recognition of granulocyte-macrophage colony-stimulating factor by specific S100 proteins.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a pleiotropic myelopoietic growth factor and proinflammatory cytokine, clinically used for multiple indications and serving as a promising target for treatment of many disorders, including cancer, multiple sclerosis, rheumatoid arthritis, psoriasis, asthma, COVID-19. We have previously shown that dimeric Ca2+-bound forms of S100A6 and S100P proteins, members of the multifunctional S100 protein family, are specific to GM-CSF. To probe selectivity of these interactions, the affinity of recombinant human GM-CSF to dimeric Ca2+-loaded forms of 18 recombinant human S100 proteins was studied by surface plasmon resonance spectroscopy. Of them, only S100A4 protein specifically binds to GM-CSF with equilibrium dissociation constant, Kd, values of 0.3-2 µM, as confirmed by intrinsic fluorescence and chemical crosslinking data. Calcium removal prevents S100A4 binding to GM-CSF, whereas monomerization of S100A4/A6/P proteins disrupts S100A4/A6 interaction with GM-CSF and induces a slight decrease in S100P affinity for GM-CSF. Structural modelling indicates the presence in the GM-CSF molecule of a conserved S100A4/A6/P-binding site, consisting of the residues from its termini, helices I and III, some of which are involved in the interaction with GM-CSF receptors. The predicted involvement of the 'hinge' region and F89 residue of S100P in GM-CSF recognition was confirmed by mutagenesis. Examination of S100A4/A6/P ability to affect GM-CSF signaling showed that S100A4/A6 inhibit GM-CSF-induced suppression of viability of monocytic THP-1 cells. The ability of the S100 proteins to modulate GM-CSF activity is relevant to progression of various neoplasms and other diseases, according to bioinformatics analysis. The direct regulation of GM-CSF signaling by extracellular forms of the S100 proteins should be taken into account in the clinical use of GM-CSF and development of the therapeutic interventions targeting GM-CSF or its receptors.

S100A4 modulates cell proliferation, apoptosis and fibrosis in the hyperplastic prostate.

Benign prostatic hyperplasia (BPH) is one of the most common diseases in elderly men worldwide that may result in lower urinary tract symptoms (LUTS). At present, the specific pathophysiological mechanism for BPH/LUTS LUTS remains unclear. S100 calcium binding protein A4 (S100A4), a member of the calcium binding protein family, regulates a variety of biological processes including cell proliferation, apoptosis and fibrosis. The aim of the current study was to explore and clarify the possible role of S100A4 in BPH/LUTS. The human prostate stromal cell line (WPMY-1), rat prostate epithelial cells, human prostate tissues and two BPH rat models were employed in this study. The expression and localization of S100A4 were detected by quantitative real time PCR (qRT-PCR), immunofluorescence microscopy, Western blotting and immunohistochemistry analysis. Also, S100A4 knockdown or overexpression cell models were constructed and a BPH rat model was induced with testosterone propionate (T) or phenylephrine (PE). The BPH animals were treated with Niclosamide, a S100A4 transcription inhibitor. Results demonstrated that S100A4 was mainly localized in human prostatic stroma and rat prostatic epithelium, and showed a higher expression in BPH. Knockdown of S100A4 induced cell apoptosis, cell proliferation arrest and a reduction of tissue fibrosis markers. Overexpression of S100A4 reversed the aforementioned changes. We also demonstrated that S100A4 regulated proliferation and apoptosis mainly through the ERK pathway and modulated fibrosis via Wnt/ß-catenin signaling. In conclusion, our novel data demonstrate that S100A4 could play a crucial role in BPH development and may be explored as a new therapeutic target of BPH.

Evaluation of Extracellular Matrix Remodeling in Full-thickness Skin Grafts in Mice.

Abdominal hernia is a protruding weakness in the abdominal wall. It affects abdominal strength and life quality and can lead to complications due to intestinal entrapment. Autologous full-thickness skin graft (FTSG) has recently become an alternative material for reinforcement in the surgical repair of large abdominal hernias instead of synthetic mesh. FTSG eventually integrates with the abdominal wall, but the long-term fate of the graft itself is not fully understood. This has implications as to how these grafts should be optimally used and handled intraoperatively. This study investigates the remodeling of FTSG in either the onlay or the intraperitoneal position 8 weeks after FTSG transplantation in an experimental mouse model. There was a significant presence of fibroblasts, indicated by vimentin and S100A4 staining, but there were significant variations among animals as to how much of the graft had been remodeled into dense connective tissue. This correlated significantly with the proportion of vimentin-positive cells in the dense connective tissue. We also found that collagen hybridizing peptide staining intensity, a marker of active remodeling, was significantly associated with the proportion of S100A4-positive cells in the dense connective tissue of the FTSG.

S100A4 Is a Key Facilitator of Thoracic Aortic Dissection.

Background: Thoracic aortic dissection (TAD) is one of the cardiovascular diseases with high incidence and fatality rates. Vascular smooth muscle cells (VSMCs) play a vital role in TAD formation. Recent studies have shown that extracellular S100A4 may participate in VSMCs regulation. However, the mechanism(s) underlying this association remains elusive. Consequently, this study investigated the role of S100A4 in VSMCs regulation and TAD formation. Methods: Hub genes were screened based on the transcriptome data of aortic dissection in the Gene Expression Synthesis database. Three-week-old male S100A4 overexpression (AAV9- S100A4 OE) and S100A4 knockdown (AAV9- S100A4 KD) mice were exposed to ß-aminopropionitrile monofumarate through drinking water for 28 days to create the murine TAD model. Results: S100A4 was observed to be the hub gene in aortic dissection. Furthermore, overexpression of S100A4 was exacerbated, whereas inhibition of S100A4 significantly improved TAD progression. In the TAD model, the S100A4 was observed to aggravate the phenotypic transition of VSMCs. Additionally, lysyl oxidase (LOX) was an important target of S100A4 in TAD. S100A4 interacted with LOX in VSMCs, reduced mature LOX (m-LOX), and decreased elastic fiber deposition, thereby disrupting extracellular matrix homeostasis and promoting TAD development. Elastic fiber deposition in human aortic tissues was negatively correlated with the expression of S100A4, which in turn, was negatively correlated with LOX. Conclusions: Our data showed that S100A4 modulates TADprogression, induces lysosomal degradation of m-LOX, and reduces the deposition of elastic fibers by interacting with LOX, thus contributing to the disruption of extracellular matrix homeostasis in TAD. These findings suggest that S100A4 may be a new target for the prevention and treatment of TAD.

S100A4 a classical DAMP as a therapeutic target in fibrosis.

Fibrosis regardless of aetiology is characterised by persistently activated myofibroblasts that are contractile and secrete excessive amounts of extracellular matrix molecules that leads to loss of organ function. Damage-Associated Molecular Patterns (DAMPs) are endogenous host-derived molecules that are released from cells dying or under stress that can be triggered by a variety of insults, either chemical or physical, leading to an inflammatory response. Among these DAMPs is S100A4, part of the S100 family of calcium binding proteins that participate in a variety of cellular processes. S100A4 was first described in context of cancer as a pro-metastatic factor. It is now appreciated that aside from its role in cancer promotion, S100A4 is intimately involved in tissue fibrosis. The extracellular form of S100A4 exerts its effects through multiple receptors including Toll-Like Receptor 4 and RAGE to evoke signalling cascades involving downstream mediators facilitating extracellular matrix deposition and myofibroblast generation and can play a role in persistent activation of myofibroblasts. S100A4 may be best understood as an amplifier of inflammatory and fibrotic processes. S100A4 appears critical in systemic sclerosis pathogenesis and blocking the extracellular form of S100A4 in vivo in various animal models of disease mitigates fibrosis and may even reverse established disease. This review appraises S100A4's position as a DAMP and its role in fibrotic conditions and highlight therapeutically targeting this protein to halt fibrosis, suggesting that it is a tractable target.

S100A4 reprofiles lipid metabolism in mast cells via RAGE and PPAR-γ signaling pathway.

S100A4 is implicated in metabolic reprogramming across various cell types and is known to propel the progression of numerous diseases including allergies. Nonetheless, the influence of S100A4 on mast cell metabolic reprogramming during allergic disorders remains unexplored. Utilizing a mast cell line (C57), cells were treated with recombinant mouse S100A4 protein, with or without a PPAR-γ agonist (ROSI) or a RAGE inhibitor (FPS-ZM1). Subsequent assessments were conducted for mast cell activation and lipid metabolism. S100A4 induced mast cell activation and the release of inflammatory mediators, concurrently altering molecules involved in lipid metabolism and glycolysis over time. Furthermore, S100A4 stimulation resulted in cellular oxidative stress and mitochondrial dysfunction. Alterations in the levels of pivotal molecules within the RAGE/Src/JAK2/STAT3/PPAR-γ and NF-κB signaling pathways were noted during this stimulation, which were partially counteracted by ROSI or FPS-ZMI. Additionally, a trend of metabolic alterations was identified in patients with allergic asthma who exhibited elevated serum S100A4 levels. Correlation analysis unveiled a positive association between serum S100A4 and serum IgE, implying an indirect association with asthma. Collectively, our findings suggest that S100A4 regulates the lipid-metabolic reprogramming of mast cells, potentially via the RAGE and PPAR-γ-involved signaling pathway, offering a novel perspective in the disease management in patients with allergic disorders.

Immunocompetent mouse models revealed that S100A4+ monocytes/macrophages facilitate long-term Zika virus infection in the testes.

During its global epidemic, Zika virus (ZIKV) attracted widespread attention due to its link with various severe neurological symptoms and potential harm to male fertility. However, the understanding of how ZIKV invades and persists in the male reproductive system is limited due to the lack of immunocompetent small animal models. In this study, immunocompetent murine models were generated by using anti-IFNAR antibody blocked C57BL/6 male mice and human STAT2 (hSTAT2) knock in (KI) male mice. After infection, viral RNA could persist in the testes even after the disappearance of viremia. We also found a population of ZIKV-susceptible S100A4+ monocytes/macrophages that were recruited into testes from peripheral blood and played a crucial role for ZIKV infection in the testis. By using single-cell RNA sequencing, we also proved that S100A4+ monocytes/macrophages had a great impact on the microenvironment of ZIKV-infected testes, thus promoting ZIKV-induced testicular lesions. In conclusion, this study proposed a novel mechanism of long-term ZIKV infection in the male reproductive system.

Claudin-18.2 mediated interaction of gastric Cancer cells and Cancer-associated fibroblasts drives tumor progression.

BACKGROUND: Claudin-18.2 (CLDN18.2) has emerged as an alluring therapeutic target against gastrointestinal tumors in recent years. However, a thorough understanding of its regulatory mechanism in gastric cancer remains elusive. METHODS: We presented a comprehensive study comprising 185 gastric cancer patients, which included 112 cases with high CLDN18.2 expression and 73 cases with low CLDN18.2 expression as determined by immunohistochemistry. After overdressed CLDN18.2 in AGS and NUGC4 cell lines, we elucidated the functions of CLDN18.2 in connecting gastric cancer cells and cancer-associated fibroblasts (CAFs) through an in vitro adhesion models and in vivo lung colonization models. The molecular mechanism underlying CLDN18.2-mediated interaction between gastric cancer cells and CAFs was identified through RNA sequencing and protein-proximity labeling techniques in vivo. RESULTS: In our own cohort, a correlation was observed between high levels of CLDN18.2 expression and advanced cancer stage, poor prognosis, and heightened infiltration of CAFs. We elucidated a pivotal role of CLDN18.2 in mediating adhesion between gastric cancer cells and CAFs, which leads to the adhesion of cancer cells to stroma tissue and facilitates the clustering of cancer cells and CAFs into embolus, enhancing gastric cancer's metastatic progression and the risk of embolic death. Mechanistically, it was discovered that CAFs can activate adhesion and metastasis-related signaling pathways in CLDN18.2-positive gastric cancer cells. Furthermore, using an in vivo protein-proximity labeling approach, we identified S100 calcium binding protein A4 (S100A4) as a distinctive marker of CAFs that interacts with CLDN18.2 to enhance gastric cancer progression. CONCLUSIONS: Our findings illuminated the role of the CLDN18.2-mediated interaction between cancer cells and CAFs in promoting gastric cancer progression and embolism, thereby providing insight into potential therapeutic avenues for CLDN18.2 positive cancers. Video Abstract.

S100A4-neutralizing monoclonal antibody 6B12 counteracts the established experimental skin fibrosis induced by bleomycin.

OBJECTIVES: Our previous studies have demonstrated that the Damage Associated Molecular Pattern (DAMP) protein, S100A4, is overexpressed in the involved skin and peripheral blood of patients with SSc. It is associated with skin and lung involvement, and disease activity. By contrast, lack of S100A4 prevented the development of experimental dermal fibrosis. Herein we aimed to evaluate the effect of murine anti-S100A4 mAb 6B12 in the treatment of preestablished experimental dermal fibrosis. METHODS: The effects of 6B12 were assessed at therapeutic dosages in a modified bleomycin-induced dermal fibrosis mouse model by evaluating fibrotic (dermal thickness, proliferation of myofibroblasts, hydroxyproline content, phosphorylated Smad3-positive cell count) and inflammatory (leukocytes infiltrating the lesional skin, systemic levels of selected cytokines and chemokines) outcomes, and transcriptional profiling (RNA sequencing). RESULTS: Treatment with 7.5 mg/kg 6B12 attenuated and might even reduce pre-existing dermal fibrosis induced by bleomycin as evidenced by reduction in dermal thickness, myofibroblast count and collagen content. These antifibrotic effects were mediated by the downregulation of TGF-ß/Smad signalling and partially by reducing the number of leukocytes infiltrating the lesional skin and decrease in the systemic levels of IL-1α, eotaxin, CCL2 and CCL5. Moreover, transcriptional profiling demonstrated that 7.5 mg/kg 6B12 also modulated several profibrotic and proinflammatory processes relevant to the pathogenesis of SSc. CONCLUSION: Targeting S100A4 by the 6B12 mAb demonstrated potent antifibrotic and anti-inflammatory effects on bleomycin-induced dermal fibrosis and provided further evidence for the vital role of S100A4 in the pathophysiology of SSc.

A novel mechanoeffector role of fibroblast S100A4 in myofibroblast transdifferentiation and fibrosis.

Fibroblast to myofibroblast transdifferentiation mediates numerous fibrotic disorders, such as idiopathic pulmonary fibrosis (IPF). We have previously demonstrated that non-muscle myosin II (NMII) is activated in response to fibrotic lung extracellular matrix, thereby mediating myofibroblast transdifferentiation. NMII-A is known to interact with the calcium-binding protein S100A4, but the mechanism by which S100A4 regulates fibrotic disorders is unclear. In this study, we show that fibroblast S100A4 is a calcium-dependent, mechanoeffector protein that is uniquely sensitive to pathophysiologic-range lung stiffness (8-25 kPa) and thereby mediates myofibroblast transdifferentiation. Re-expression of endogenous fibroblast S100A4 rescues the myofibroblastic phenotype in S100A4 KO fibroblasts. Analysis of NMII-A/actin dynamics reveals that S100A4 mediates the unraveling and redistribution of peripheral actomyosin to a central location, resulting in a contractile myofibroblast. Furthermore, S100A4 loss protects against murine in vivo pulmonary fibrosis, and S100A4 expression is dysregulated in IPF. Our data reveal a novel mechanosensor/effector role for endogenous fibroblast S100A4 in inducing cytoskeletal redistribution in fibrotic disorders such as IPF.

A pilot study of S100A4, S100A8/A9, and S100A12 in dilated cardiomyopathy: novel biomarkers for diagnosis or prognosis?

AIMS: Circulating biomarkers can provide important information for the diagnosis and prognosis of dilated cardiomyopathy (DCM). We explored novel biomarkers for the diagnosis and prognosis of DCM to improve clinical decision-making. METHODS AND RESULTS: A total of 238 DCM patients and 65 control were consecutively enrolled at Zhongshan Hospital between January 2017 and January 2019. In the screening set, four DCM patients and four controls underwent measurements of serum proteomic analysis. Seventy-six differentially expressed circulating proteins were screened by data-independent acquisition proteomics, and three of these proteins (S100A4, S100A8/A9, and S100A12) were validated by multiple-reaction monitoring-mass spectrometry. In the validation set, subsequently, a total of 234 DCM patients and 61 control subjects were evaluated by enzyme-linked immunosorbent assay. Circulating S100A4, S100A8/A9, and S100A12 were significantly increased in DCM patients (P < 0.001). These three proteins were significant positively correlated with other parameters, such as Lg (NT-proBNP), IL-1ß, TGF-ß, CRP, left ventricular end-diastolic diameter, and left ventricular end-systolic diameter, whereas they were negatively correlated with left ventricular ejection fraction, respectively (P < 0.05). The receiver operator characteristic curve showed the combination of S100A4, S100A8/A9, and S100A12 [area under curve (AUC) 0.88, 95% confidence interval (CI) 0.84-0.93] was better than single S100A4 (AUC 0.74, 95% CI 0.68-0.81), S100A8/A9 (AUC 0.82, 95% CI 0.77-0.88), or S100A12 (AUC 0.80, 95% CI 0.72-0.88) in the diagnosis of DCM (P < 0.01). After a median follow-up period of 33.5 months, 110 patients (47.01%) experienced major adverse cardiac events (MACEs), including 46 who had cardiac deaths and 64 who had heart failure rehospitalizations. Kaplan-Meier analysis indicated that the DCM patients with ≥75th percentile level of S100A4 had a significantly higher incidence of MACEs than those with <75th percentile level of S100A4 (61.40% vs. 42.37%, P < 0.05). There were no significant differences of MACE rate among DCM patients with different concentrations of S100A8/A9 and S100A12 (P > 0.05). Cox proportional hazards regression analysis revealed that S100A4 [≥75th percentile vs. <75th percentile: hazard ratio (HR) 1.65; 95% CI 1.11-2.45] remained significant independent predictors for MACEs (P < 0.05); however, S100A8/A9 and S100A12 were not independent factors for predicting MACE (P ≥ 0.05). CONCLUSIONS: S100A4, S100A8/A9, and S100A12 may be additional diagnostic tools for human DCM recognition, and the combination of these three indicators helped to improve the accuracy of a single index to diagnose DCM. Additionally, S100A4 was identified as a significant predictor of prognosis in patients with DCM.

Inhibition of TLR4/NF-κB pathway and endoplasmic reticulum stress by overexpressed S100A4 ameliorates retinal ischemia-reperfusion injury of mice.

Retinal ischemia exists in various ischemic retinopathies including glaucoma, contributing to the death of retinal neurons. Calcium binding protein S100A4 is important in tumors, and our previous study found that S100A4 protects retinal ganglion cells (RGCs) against retinal ischemia-reperfusion (I/R) injury. This study was aimed to further discuss the neuroprotection and mechanisms of S100A4 in retinal I/R of mice. The rAAV-EF1α-s100a4-EGFP-WPRE or rAAV-EF1α-EGFP-WPRE-Pa was injected intravitreally 4 weeks before I/R. S100A4, molecules in TLR4 signaling pathway and endoplasmic reticulum (ER) stress branches, inflammatory molecules, and surviving RGCs and cholinergic amacrine (ChAT) cells were determined by quantitative PCR, western blot, or immunofluorescent staining. The apoptosis and necrosis of retinal neurons induced by I/R were inhibited by overexpressed S100A4. RGCs, ChAT cells, and the retinal function were preserved by S100A4 overexpressing 7 days after I/R. Mechanistically, the beneficial effects of S100A4 may be mediated by inhibiting the activation of TLR4 signaling pathway and alleviating ER stress, leading to the attenuation of inflammatory response of the retina after I/R. Our findings indicated that S100A4 has neuroprotective effect against retinal I/R injury, and promoting S100A4 expression may be an effective strategy to inhibit retinal neurons from degeneration in ischemic retinopathy.

Examining the Aryl Hydrocarbon Receptor Network in the Placental Tissues of Pregnancies Complicated by Pre-Eclampsia: An Explorative Case-Control Analysis.

Severe maternal and newborn morbidity and mortality associated with pre-eclampsia, which are caused partly by premature delivery, affect a factual proportion of pregnancies. Despite its prevalence, the underlying causes of pre-eclampsia remain elusive, with emerging evidence implicating the aryl hydrocarbon receptor (AhR) in its pathogenesis. This study sought to elucidate the involvement of the AhR and its associated pathway in pre-eclampsia by comparing placental components of the AhR pathway in pregnant individuals with and without pre-eclampsia. This case-control investigation was conducted at the University Hospital of Udine from May 2021 to February 2023. The AhR was assessed using immunohistochemistry and immunofluorescence, and its mRNA was evaluated using a Real-Time Quantitative Reverse Transcription PCR. Levels of mRNA expression were also estimated for other components of the AhR pathway (CYP1B1, IDO1, ARNT, TIPARP, S100A4, and AHRR). Our findings show decreased levels of expression of AhR, IDO1, ARNT, TiPARP, and S100A4 in the placental tissues of individuals with pre-eclampsia compared to controls (p < 0.05). The AhR exhibited a distinct localization within the syncytiotrophoblast (nuclei and cytoplasm) and CD45-positive cells (nuclei and cytoplasm). Furthermore, a significant positive correlation between the AhR and S100A4 (rho = 0.81) was observed in normal placentas, while CYP1B1 displayed a significant negative correlation with the AhR (rho = -0.72), within addition to its negative correlation with TiPARP (rho = -0.83). This study illuminates pre-eclampsia's molecular aberrations, suggesting new diagnostic, therapeutic, and mechanistic approaches. This study emphasizes the need for more research to validate and broaden these findings to improve the management of this complex pregnancy condition.

Inhibition of Increased Invasiveness of Breast Cancer Cells With Acquired Tamoxifen Resistance by Suppression of CYR61.

BACKGROUND/AIM: Hormone sensitivity-targeted therapy with selective estrogen receptor modulators (SERMs), such as 4-hydroxytamoxifen (4-OHT), is the mainstay of treatment for breast cancers (BCs) that express estrogen receptor α (ERα). However, development of resistance limits this therapy approach. The question arises whether changes associated with 4-OHT resistance could be exploited therapeutically. MATERIALS AND METHODS: First, 4-OHT-resistant sublines of ERα-positive breast carcinoma cell lines MCF-7 and T47D were generated. Viability was assessed by the Alamar Blue assay. Cell invasion was quantified in modified Boyden chambers with Matrigel. Changes in expression of CYR61, S100A4, and ERα were examined by RT-qPCR. Expression of CYR61 was suppressed by transient gene silencing using siRNA. Successful suppression was verified by western blot. Efficacy of 4-OHT treatment was analyzed by quantification of viability using Alamar Blue assay. Correlation of CYR61 levels in patients with luminal A BC to distant metastases-free survival was determined by Kaplan-Meier analysis. RESULTS: ERα-positive MCF-7 and T47D BC cells exhibit an extremely weak invasion rate. Acquired tamoxifen resistance significantly increased the invasive behavior of both tamoxifen-resistant MCF-7-TR and T47D-TR sublines. In addition, expression of CYR61 and S100A4 showed significantly increased levels, whereas expression of ERα was decreased. Suppression of CYR61 expression resulted in a significant decreased invasion rate. In addition, expression of S100A4 was reduced, whereas expression of ERα was increased. Furthermore, suppression of CYR61 resulted in re-sensitization to 4-OHT. High CYR61 levels in patients with luminal A BC resulted in reduced distant metastases-free survival. CONCLUSION: The prometastatic factor CYR61 appears to play an important role in the increased invasiveness of tamoxifen-resistant ERα-positive BC cells. Its suppression leads to a lower invasion rate. Given the few therapeutic options available for tamoxifen-resistant BC, therapy that reduces CYR61 may improve its treatability in future.

Anti-S100A4 antibody administration alleviates bronchial epithelial-mesenchymal transition in asthmatic mice.

We elucidated the effect of S100A4 on airway remodeling by regulating airway inflammation and epithelial-mesenchymal transition (EMT) in mouse models of asthma. Asthmatic mouse models were established by sensitization and challenged with ovalbumin (OVA). Anti-S100A4 antibody or control IgG antibody was administered daily before the OVA challenge. After the last challenge, airway inflammation and airway hyperresponsiveness were measured; lung tissues and bronchoalveolar lavage fluid (BALF) were harvested. Lung tissue sections were stained and evaluated for pathological changes. Levels of inflammatory cytokines were measured using ELISA. Levels of S100A4 and EMT markers were determined via western blotting analysis. Human bronchial epithelial cells were stimulated with 100 mg/mL house dust mites (HDMs) to evaluate the effect of S100A4 downregulation on EMT in vitro. S100A4 was increased in lung tissues and BALF from asthmatic mice. The asthmatic mice presented airway hyperresponsiveness, airway inflammation, and airway remodeling. After anti-S100A4 antibody administration, pathophysiological signs, including airway hyperresponsiveness and increased infiltration of inflammatory cells, were attenuated. Additionally, anti-S100A4 administration downregulated vimentin and α-SMA expression and upregulated E-cadherin expression in OVA-challenged mice. S100A4 downregulation also inhibited EMT process in HDM-stimulated 16HBE cells. Anti-S100A4 antibody administration alters airway remodeling by preventing EMT in mouse models of asthma.

Elafibranor upregulates the EMT-inducer S100A4 via PPARß/δ.

Elafibranor is a dual peroxisome proliferator-activated receptor (PPAR)α and ß/δ agonist that has reached a phase III clinical trial for the treatment of metabolic dysfunction-associated steatotic liver disease (MASLD). Here, we examined the effects of elafibranor in mice fed a choline-deficient high-fat diet (CD-HFD), a model of metabolic dysfunction-associated steatohepatitis (MASH) that presents obesity and insulin resistance. Our findings revealed that elafibranor treatment ameliorated steatosis, inflammation, and fibrogenesis in the livers of CD-HFD-fed mice. Unexpectedly, elafibranor also increased the levels of the epithelial-mesenchymal transition (EMT)-promoting protein S100A4 via PPARß/δ activation. The increase in S100A4 protein levels caused by elafibranor was accompanied by changes in the levels of markers associated with the EMT program. The S100A4 induction caused by elafibranor was confirmed in the BRL-3A rat liver cells and a mouse primary hepatocyte culture. Furthermore, elafibranor reduced the levels of ASB2, a protein that promotes S100A4 degradation, while ASB2 overexpression prevented the stimulating effect of elafibranor on S100A4. Collectively, these findings reveal an unexpected hepatic effect of elafibranor on increasing S100A4 and promoting the EMT program.