Olive leaf extract counteracts epithelial to mesenchymal transition process induced by peritoneal dialysis, through the inhibition of TGFβ1 signaling

Association between the composite dietary antioxidant index and chronic kidney disease: evidence from NHANES 2011-2018

Objectives: There is growing evidence that antioxidant-rich diets protect against chronic kidney disease (CKD). However, the relationship between the Composite Dietary Antioxidant Index (CDAI), an important measure of an antioxidant diet, and CKD has received little attention. Therefore, here we investigated the relationship between the CDAI and CKD through a cross-sectional analysis of the National Health and Nutrition Examination Survey (NHANES) 2011-2018 data. Methods: The CDAI was calculated based on the intake of six dietary antioxidants. A survey-based multivariate linear regression analysis was performed to analyze the independent relationship between the CDAI and CKD. Weighted multivariate regression and subgroup analyses were conducted to explore the relationship between the CDAI and CKD. Results: A total of 6874 NHANES participants represented 181.9 million non-institutionalized US residents (mean age, 46.43 ± 0.38 years; 49.87% female; 40.62% non-Hispanic white; 20.24% non-Hispanic black; and 13.94% Mexican American). The weighted linear regression model with full adjustment for confounding variables was -0.0155 (-0.0417, 0.0107) for Q2 (P for trend <0.0001), -0.0052 (-0.0346, 0.0242) for Q3 (P for trend <0.0001), and -0.0305 (-0.0491, -0.0120) for Q4 (P for trend = 0.0094) upon comparison with the lowest quartile of the CDAI. None of the interactions in any subgroup analysis were statistically significant except for individuals with a history of diabetes or the aged population (≥60 years) (P for interaction <0.05). Conclusions: The CDAI was positively associated with a lower prevalence of CKD in adults in the United States. Further large-scale prospective studies are required to analyze the role of the CDAI in CKD.

Circ_0001666 upregulation promotes intestinal epithelial cell fibrosis in pediatric Crohn's disease via the SRSF1/BMP7 axis

The epithelial-mesenchymal transition (EMT) is closely associated with Crohn's disease (CD) related intestinal fibrosis, a condition whose prevalence is increasing annually among children. Recently, the CD marker gene microarray screening revealed an upregulation of circ_0001666 in the colon tissues of CD patients, but its underlying mechanisms remain unclear. In this study, we explored the molecular mechanism of circ_0001666 in regulating EMT-mediated fibrosis in CD in vitro. The levels of circ_0001666 and EMT-associated proteins were assessed in CD clinical samples, and a CD cell model was established using TGF-β1 to induce human intestinal epithelial cells (HIECs). Additionally, the expression levels of genes and proteins related to EMT and fibrosis were analyzed by quantitative real-time PCR and western blot, cell migration, and invasion were assessed via wound healing assay and transwell, respectively, and RNA pull-down and RNA immunoprecipitation assays were performed to verify the relationship between SRSF1 and BMP7 or circ_0001666. Circ_0001666 was overexpressed in the intestinal mucosal tissues of CD patients and was positively correlated with EMT. Silencing circ_0001666 inhibited the migration, invasion, EMT, and fibrosis of HIECs induced by TGF-β1. Mechanistically, circ_0001666 regulated BMP7 expression by interacting with SRSF1. Furthermore, the effects of inhibiting circ_0001666 on HIECs could be partially reversed by overexpressing SRSF1 or silencing BMP7. Collectively, circ_0001666 regulates TGF-β1-induced HIEC migration, invasion, EMT, and fibrosis. Circ_0001666 also promoted EMT-mediated fibrosis by interacting with SRSF1 to accelerate BMP7 mRNA decay. These findings provide new insights into the pathogenesis of CD and suggest that circ_0001666 might be a potential therapeutic target for CD.

N-methylpiperazine-diepoxyovatodiolide ameliorates peritoneal fibrosis via suppressing TGF-β/Smad and JAK/STAT signaling pathway

Peritoneal fibrosis (PF) is the main cause of peritoneal ultrafiltration failure in patients undergoing long-term peritoneal dialysis (PD). Epithelial-mesenchymal transition (EMT) is the key pathogenesis of PF. However, currently, no specific treatments are available to suppress PF. N-methylpiperazine-diepoxyovatodiolide (NMPDOva) is a newly synthesized compound that involves a chemical modification of ovatodiolide. In this study, we aimed to explore the antifibrotic effects of NMPDOva in PD-related PF and underlying mechanisms. A mouse model of PD-related PF was established via daily intraperitoneal injection of 4.25% glucose PD fluid. In vitro studies were performed using the transforming growth factor-beta1 (TGF-β1)-stimulated HMrSV5 cell line. Pathological changes were observed, and fibrotic markers were significantly elevated in the peritoneal membrane in mice model of PD-related PF. However, NMPDOva treatment significantly alleviated PD-related PF by decreasing the extracellular matrix accumulation. NMPDOva treatment decreased the expression of fibronectin, collagen Ⅰ, and alpha-smooth muscle actin (α-SMA) in mice with PD-related PF. Moreover, NMPDOva could alleviate TGF-β1-induced EMT in HMrSV5 cells, inhibited phosphorylation and nuclear translocation of Smad2/3, and increased the expression of Smad7. Meanwhile, NMPDOva inhibited phosphorylation of JAK2 and STAT3. Collectively, these results indicated that NMPDOva prevents PD-related PF by inhibiting the TGF-β1/Smad and JAK/STAT signaling pathway. Therefore, because of these antifibrotic effects, NMPDOva may be a promising therapeutic agent for PD-related PF.

Olea europaea L. Leaf Extract Alleviates Fibrosis Progression and Oxidative Stress Induced by Bleomycin on a Murine Model of Lung Fibrosis

In this study, we aim to investigate the effect of industrial Olea europaea L. leaf extract (OLE) against bleomycin (BLM)-induced pulmonary fibrosis (PF) in rats. Male Wistar rats were treated with a single intratracheal injection of BLM (4 mg/kg) and a daily intraperitoneal injection of OLE (10, 20, and 40 mg/kg) for 4 weeks. Results of HPLC and LC-MS analysis revealed a large amount of oleuropein (15.43%/DW) in OLE. BLM induced apparent damage of lung architecture with condensed collagen bundles, increased lipid peroxidation which has been deduced from malondialdehyde (MDA) levels: (.9 ± .13 vs .25 ± .12 nmol/mg protein) and hydroxyproline content (.601 ± .22 vs .154 ± .139 mg/g of lung tissue) and decreased catalase (CAT) (5.93.10-5 ± 4.23.10-5 vs 6.41.10-4 ± 2.33.10-4 μmol/min/mg protein) and superoxide dismutase (SOD) (28.73 ± 3.34 vs 50.13 ± 2.1 USOD/min/mg protein) levels compared to the control. OLE treatment (40 mg/kg) stabilized MDA content (.32 ± .15 and .27 ± .13 vs .9 ± .13 nmol/mg protein), normalized SOD (61.27 ± 13.37 vs 28.73 ± 3.34 USOD/min/mg protein), and CAT (5.2.10-4 ±1.8.10-4 vs 5.93.10-5 ± 4.23.10-5 μmol/min/mg protein) activities and counteracted collagen accumulation and hydroxyproline content (.222 ± .07 vs .601 ± .22 mg/g of lung tissue) in the lung parenchyma. Finally, OLE might have a potent protective effect against PF by regulating oxidative parameters and attenuating collagen deposition, due to the existence of large amount of bioactive phenolic molecules.

Approaches in Hydroxytyrosol Supplementation on Epithelial-Mesenchymal Transition in TGFβ1-Induced Human Respiratory Epithelial Cells

Hydroxytyrosol (HT) is an olive polyphenol with anti-inflammatory and antioxidant properties. This study aimed to investigate the effect of HT treatment on epithelial-mesenchymal transition (EMT) in primary human respiratory epithelial cells (RECs) isolated from human nasal turbinate. HT dose-response study and growth kinetic study on RECs was performed. Several approaches on HT treatment and TGFβ1 induction with varying durations and methods was studied. RECs morphology and migration ability were evaluated. Vimentin and E-cadherin immunofluorescence staining and Western blotting [E-cadherin, vimentin, SNAIL/SLUG, AKT, phosphorylated (p)AKT, SMAD2/3 and pSMAD2/3] were performed after 72-h treatment. In silico analysis (molecular docking) of HT was performed to evaluate the potential of HT to bind with the TGFβ receptor. The viability of the HT-treated RECs was concentration-dependent, where the median effective concentration (EC₅₀) was 19.04 μg/mL. Testing of the effects of 1 and 10 µg/mL HT revealed that HT suppressed expression of the protein markers vimentin and SNAIL/SLUG while preserving E-cadherin protein expression. Supplementation with HT protected against SMAD and AKT pathway activation in the TGFβ1-induced RECs. Furthermore, HT demonstrated the potential to bind with ALK5 (a TGFβ receptor component) in comparison to oleuropein. TGFβ1-induced EMT in RECs and HT exerted a positive effect in modulating the effects of EMT.

Verbascoside and isoverbascoside ameliorate transforming growth factor β1-induced collagen expression by lung fibroblasts through Smad/non-Smad signaling pathways

AIMS

Pulmonary fibrosis (PF) is a chronic, irreversible, and debilitating lung disease that typically leads to respiratory failure, and is a major cause of morbidity and mortality. Few drugs are effective for the treatment of patients with PF or for reducing the rate of disease progression.

MAIN METHODS

Transforming growth factor-β1 (TGF-β1) is a profibrotic cytokine that signals through Smad and non-Smad pathways. Verbascoside (VB) and isoverbascoside (isoVB) exhibit anti-oxidative and anti-inflammatory activities, however, their anti-fibrotic effects remain unclear. This study evaluated the effects of VB and isoVB on TGF-β1-stimulated murine lung fibroblasts (MLg 2908) and also human lung fibroblasts (confirmed by immunostaining).

KEY FINDINGS

Neither VB nor isoVB had a cytotoxic effect on MLg 2908 fibroblasts. Both compounds (10 μM) reduced intracellular reactive oxygen species and markedly attenuated collagen I expression in TGF-β1 (5 ng/ml)-induced MLg 2908 cells compared to TGF-β1 alone. Both compounds suppressed the TGF-β1-induced phosphorylation of Smad2/3 and ERK/p38 mitogen-activated protein kinases (MAPKs). VB and isoVB, but not pirfenidone and nintedanib, inhibited TGF-β1-induced pSmad2/3, ERK/p38 MAPK, and collagen I expression. VB and isoVB also decreased collagen I deposition in TGF-β1-induced MLg 2908 cells. Only isoVB significantly suppressed collagen I deposition in TGF-β1-induced human pulmonary cells. Our results indicated that VB and isoVB may exert antifibrotic effects by inhibiting TGF-β1-induced collagen I expression via inhibition of oxidative stress and downregulation of the Smad/non-Smad pathway.

SIGNIFICANCE

The present findings suggest that VB or isoVB may be used as a supplement to alleviate PF.

Oleuropein inhibits invasion of squamous cell carcinoma of the head and neck through TGF-β1 signaling pathway

Background

Squamous cell carcinoma of the head and neck (SCCHN) is globally the sixth most common cancer. TGF-β1 is a key regulator of cell proliferation and differentiation, and it induces the epithelial-mesenchymal transition (EMT) by activating Smad2 signaling in SCCHN cells. Previous studies have revealed that oleuropein (OL) can inhibit the EMT alterations and migration of cancer cells. The aim of this study was to examine the involvement of TGF-β1 signaling pathway in SCCHN and the effect of OL on it.

Methods

Through in vitro experiments at cellular level and in vivo evaluation in mouse xenograft tumor model, with morphological and Western blotting assays, we examined the effects of OL on TGF-β1-mediated signaling pathway in Tu686, CAL-27 and 686LN-M2 tumor cell lines.

Results

We found that OL reversed the TGF-β1-induced EMT, and changed the morphology of cells and the expression levels of epithelial and interstitial markers. Wound-healing and transwell invasion assays indicated that OL reversed the TGF-β1-promoted cell migration and invasion dramatically. The effects of OL were also verified in xenograft tumor model of mice, and the findings were identical to the in vitro assays.

Conclusion

This study demonstrated that OL inhibits the growth and metastasis of SCCHN by interfering with the TGF-β1 signaling pathway, and the findings are beneficial for the development of prevention and treatment strategy of SCCHN. Due to the low toxicity and less side effects, OL may be of potential value in the inhibition of metastasis of SCCHN and improve survival.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09979-2.

Oleuropein Counteracts Both the Proliferation and Migration of Intra- and Extragonadal Seminoma Cells

Recent and growing literature has reported that oleuropein (OLE), the main polyphenol in olive leaf extract, inhibits tumor cell proliferation and reduces the invasiveness properties of cancer cells; therefore, OLE may play a significant role in the development of new drugs for cancer treatment. These antineoplastic properties have been reported in many experimental cancer models, but the effect of OLE on seminoma cells is yet to be evaluated. In the present study, we demonstrate, for the first time, that OLE reduces cell viability in both intra- and extragonadal TCAM-2 and SEM-1 seminoma cells, respectively, in a dose-dependent manner. As shown by Western-blot analysis, OLE exposure reduced cyclin-D1 expression and upregulated p21^Cip/WAF1, concomitantly affecting the upstream pathway of NF-κB, leading to the reduction of its nuclear content, thereby suggesting that OLE could modulate cell-cycle regulators by inhibiting NF-κB. Moreover, Annexin V staining revealed that OLE induced apoptosis in cancer cells and upregulated the pro-apoptotic factor BAX. Through wound-healing scratch and transmigration assays, we also demonstrated that OLE significantly reduced the migration and motility of TCAM-2 and SEM-1 cells, and downregulated the expression of TGFβ-1, which is known to be the main pro-fibrotic factor involved in the acquisition of the migratory and invasive properties of cancer cells. Collectively, our results indicate that OLE reduces seminoma cell proliferation, promotes apoptosis, and counteracts cell migration and motility. Further studies are needed to explore the molecular mechanisms underlying these observed effects.

Rapamycin promotes autophagy cell death of Kaposi's sarcoma cells through P75NTR activation

The mammalian target of rapamycin inhibitor (mTOR-I) Rapamycin, a drug widely used in kidney transplantation, exerts important anti-cancer effects, particularly in Kaposi's Sarcoma (KS), through several biological interactions. In this in vivo and in vitro study, we explored whether the activation of the autophagic pathway through the low-affinity receptor for nerve growth factor, p75^NTR , may have a pivotal role in the anti-cancer effect exerted by Rapamycin in S. Our Kimmunohistochemistry results revealed a significant hyper-activation of the autophagic pathway in KS lesions. In vitro experiments on KS cell lines showed that Rapamycin exposure reduced cell viability by increasing the autophagic process, in the absence of apoptosis, through the transcriptional activation of p75^NTR via EGR1. Interestingly, p75^NTR gene silencing prevented the increase of the autophagic process and the reduction of cell viability. Moreover, p75^NTR activation promoted the upregulation of phosphatase and tensin homolog (PTEN), a tumour suppressor that modulates the PI3K/Akt/mTOR pathway. In conclusion, our in vitro data demonstrated, for the first time, that in Kaposi's sarcoma, autophagy triggered by Rapamycin through p75^NTR represented a major mechanism by which mTOR inhibitors may induce tumour regression. Additionally, it suggested that p75^NTR protein analysis could be proposed as a new potential biomarker to predict response to Rapamycin in kidney transplant recipients affected by Kaposi's sarcoma.

Molecular pathways in peritoneal fibrosis

Peritoneal dialysis (PD) is a renal replacement therapy for patients with end-stage renal disease that is equivalent to hemodialysis with respect to adequacy, mortality, and other outcome parameters, yet providing superior quality-of-life measures and cost savings. However, long-term usage of the patient's peritoneal membrane as a dialyzer filter is unphysiological and leads to peritoneal fibrosis, which is a major factor of patient morbidity and PD technique failure, resulting in a transfer to hemodialysis or death. Peritoneal fibrosis pathophysiology involves chronic inflammation and the fibrotic process itself. Frequently, inflammation precedes membrane fibrosis development, although a bidirectional relationship of one inducing the other exists. This review aims at highlighting the histopathological definition of peritoneal fibrosis, outlining the interplay of fibrosis, angiogenesis and epithelial-to-mesenchymal transition (EMT), delineating important fibrogenic pathways involving Smad-dependent and Smad-independent transforming growth factor-β (TGF-β) as well as connective tissue growth factor (CTGF) signaling, and summarizing historic and recent studies of inflammatory pathways involving NOD-like receptor protein 3 (NLRP3)/interleukin (IL)-1β, IL-6, IL-17, and other cytokines.

Polyphenols Attenuate Highly-Glycosylated Haemoglobin-Induced Damage in Human Peritoneal Mesothelial Cells

We investigated the cytoprotective role of the dietary polyphenols on putative damage induced by Amadori adducts in Human Peritoneal Mesothelial Cells (HPMCs). Increased accumulation of early products of non-enzymatic protein glycation-Amadori adducts-in the peritoneal dialysis fluid due to their high glucose, induces severe damage in mesothelial cells during peritoneal dialysis. Dietary polyphenols reportedly have numerous health benefits in various diseases and have been used as an efficient antioxidant in the context of several oxidative stress-related pathologies. HPMCs isolated from different patients were exposed to Amadori adducts (highly glycated haemoglobin, at physiological concentrations), and subsequently treated with several polyphenols, mostly presented in our Mediterranean diet. We studied several Amadori-induced effects in pro-apoptotic and oxidative stress markers, as well as the expression of several pro-inflammatory genes (nuclear factor-kappaB, NF-kB; inducible Nitric Oxide synthetase, iNOS), different caspase-activities, level of P53 protein or production of different reactive oxygen species in the presence of different polyphenols. In fact, cytoprotective agents such as dietary polyphenols may represent an alternate approach to protect mesothelial cells from the cytotoxicity of Amadori adducts. The interference with the Amadori adducts-triggered mechanisms could represent a therapeutic tool to reduce complications associated with peritoneal dialysis in the peritoneum, helping to maintain peritoneal membrane function longer in patients undergoing peritoneal dialysis.

Loosening of the mesothelial barrier as an early therapeutic target to preserve peritoneal function in peritoneal dialysis

Phenotype transition of peritoneal mesothelial cells (MCs) including the epithelial-to-mesenchymal transition (EMT) is regarded as an early mechanism of peritoneal dysfunction and fibrosis in peritoneal dialysis (PD), producing proinflammatory and pro-fibrotic milieu in the intra-peritoneal cavity. Loosening of intercellular tight adhesion between adjacent MCs as an initial process of EMT creates the environment where mesothelium and submesothelial tissue are more vulnerable to the composition of bio-incompatible dialysates, reactive oxygen species, and inflammatory cytokines. In addition, down-regulation of epithelial cell markers such as E-cadherin facilitates de novo acquisition of mesenchymal phenotypes in MCs and production of extracellular matrices. Major mechanisms underlying the EMT of MCs include induction of oxidative stress, pro-inflammatory cytokines, endoplasmic reticulum stress and activation of the local renin-angiotensin system. Another mechanism of peritoneal EMT is mitigation of intrinsic defense mechanisms such as the peritoneal antioxidant system and anti-fibrotic peptide production in the peritoneal cavity. In addition to use of less bio-incompatible dialysates and optimum treatment of peritonitis in PD, therapies to prevent or alleviate peritoneal EMT have demonstrated a favorable effect on peritoneal function and structure, suggesting that EMT can be an early interventional target to preserve peritoneal integrity.

Asiaticoside inhibits TGF-β1-induced mesothelial-mesenchymal transition and oxidative stress via the Nrf2/HO-1 signaling pathway in the human peritoneal mesothelial cell line HMrSV5

Background

Peritoneal fibrosis (PF) is a frequent complication caused by peritoneal dialysis (PD). Peritoneal mesothelial cells (PMCs), the first barrier of the peritoneum, play an important role in maintaining structure and function in the peritoneum during PD. Mesothelial-mesenchymal transition (MMT) and oxidative stress of PMCs are two key processes of PF.

Purpose

To elucidate the efficacy and possible mechanism of asiaticoside inhibition of MMT and ROS generation in TGF-β1-induced PF in human peritoneal mesothelial cells (HPMCs).

Methods

MMT and ROS generation of HPMCs were induced by TGF-β1. To explain the anti-MMT and antioxidant role of asiaticoside, varied doses of asiaticoside, oxygen radical scavenger (NAC), TGF-β receptor kinase inhibitor (LY2109761) and Nrf2 inhibitor (ML385) were used separately. Immunoblots were used to detect the expression of signaling associated proteins. DCFH-DA was used to detect the generation of ROS. Transwell migration assay and wound healing assay were used to verify the capacity of asiaticoside to inhibit MMT. Immunofluorescence assay was performed to observe the subcellular translocation of Nrf2 and expression of HO-1.

Results

Asiaticoside inhibited TGF-β1-induced MMT and suppressed Smad signaling in a dose-dependent manner. Migration and invasion activities of HPMCs were decreased by asiaticoside. Asiaticoside decreased TGF-β1-induced ROS, especially in a high dose (150 μM) for 6 h. Furthermore, ML385 partly abolished the inhibitory effect of asiaticoside on MMT, ROS and p-Smad2/3.

Conclusions

Asiaticoside inhibited the TGF-β1-induced MMT and ROS via Nrf2 activation, thus protecting the peritoneal membrane and preventing PF.

Roles of TGFβ1 in the expression of phosphoinositide 3-kinase isoform genes and sensitivity and response of lung telocytes to PI3K inhibitors

BACKGROUND

The mouse lung telocyte cell line (TC^SV40) recently established provides further opportunities to learn TC biology and functions. The present study aims at investigating regulatory roles of phosphoinositide 3-kinase (PI3K) isoforms in TC proliferation and movement and in TGFβ1-induced sensitivity and response of lung TCs to PI3K inhibitors.

MATERIALS AND METHODS

Network and molecular interactions of genes coding PI3K family or TGFβ family proteins in mouse primary TCs were defined. Mouse lung TC^SV40 proliferation, apoptosis, cell cycle, and dynamical bio-behaviors were measured with or without TGFβ1 stimulation or PI3K catalytic isoform protein (PI3K/mTOR, PI3Kα/δ/β, PI3K p110δ, or pan-PI3K) inhibitions.

RESULTS

The present study showed the difference of network characteristics and interactions of genes coding PI3K isoform proteins or TGFβ family proteins in primary lung telocytes from mouse lungs compared to those of other cells residing in the lung. TGFβ1 had diverse effects on TC proliferation with altered TC number in G2 or S phase, independent upon the administered dose of TGFβ1. PI3Kα/δ/β, PI3K/mTOR, and PI3K p110δ were involved in TC proliferation, of which PI3Kα/δ/β was more sensitive. The effects of pan-PI3K inhibitor indicate that more PI3K isoforms were stimulated by the administering of external TGFβ1 and contributed to TGFβ1-induced TC proliferation. PI3K p110δ upregulated TC proliferation and movement dynamically without TGFβ1, and downregulated TC proliferation with TGFβ1 stimulation, but not TC movement. PI3Kα/δ/β and PI3K/mTOR were more active in TGFβ1-induced S phase accumulation and had similar dynamic effects to PI3K p110δ. Gene expression of PI3K isoforms in TCs was upregulated after TGFβ1 stimulation. The expression of PIK3CA coding p110-α or PIK3CG coding p110-γ were up- or downregulated in TCs without TGFβ1, respectively, when PI3K/mTOR, PI3Kα/δ/β, PI3K p110δ, or pan-PI3K were inhibited. TGFβ1 upregulated the expression of PIK3CA and PIK3CB, while downregulated the expression of PIK3CD and PIK3CG.

CONCLUSION

Our data imply that TGFβ1 plays divergent roles in the expression of PI3K isoform genes in lung TCs and can alter the sensitivity and response of lung TCs to PI3K inhibitors.

Dietary Antioxidant Supplements and Uric Acid in Chronic Kidney Disease: A Review

Increased serum levels of uric acid have been associated with the onset and development of chronic kidney disease (CKD), cardiovascular disease, and mortality, through several molecular pathogenetic mechanisms, such as inflammation and oxidative stress. Oxidative stress is present even in the early stages of CKD, progresses parallelly with the deterioration of kidney function, and is even more exacerbated in end-stage renal disease patients undergoing maintenance hemodialysis. Although acting in the plasma as an antioxidant, once uric acid enters the intracellular environment; it behaves as a powerful pro-oxidant. Exogenous intake of antioxidants has been repeatedly shown to prevent inflammation, atherosclerosis and oxidative stress in CKD patients. Moreover, certain antioxidants have been proposed to exert uric acid-lowering properties. This review aims to present the available data regarding the effects of antioxidant supplements on both oxidative stress and uric acid serum levels, in a population particularly susceptible to oxidative damage such as CKD patients.

Modulation of Epithelial to Mesenchymal Transition Signaling Pathways by Olea Europaea and Its Active Compounds

Epithelial-mesenchymal transition (EMT) is a significant dynamic process that causes changes in the phenotype of epithelial cells, changing them from their original phenotype to the mesenchymal cell phenotype. This event can be observed during wound healing process, fibrosis and cancer. EMT-related diseases are usually caused by inflammation that eventually leads to tissue remodeling in the damaged tissue. Prolonged inflammation causes long-term EMT activation that can lead to tissue fibrosis or cancer. Due to activation of EMT by its signaling pathway, therapeutic approaches that modulate that pathway should be explored. Olea europaea (OE) is well-known for its anti-inflammatory effects and abundant beneficial active compounds. These properties are presumed to modulate EMT events. This article reviews recent evidence of the effects of OE and its active compounds on EMT events and EMT-related diseases. Following evidence from the literature, it was shown that OE could modulate TGFβ/SMAD, AKT, ERK, and Wnt/β-catenin pathways in EMT due to a potent active compound that is present therein.