Transplantation of Brown Adipose Tissue with the Ability of Converting Omega-6 to Omega-3 Polyunsaturated Fatty Acids Counteracts High-Fat-Induced Metabolic Abnormalities in Mice

A balanced omega (ω)-6/ω-3 polyunsaturated fatty acids (PUFAs) ratio has been linked to metabolic health and the prevention of chronic diseases. Brown adipose tissue (BAT) specializes in energy expenditure and secretes signaling molecules that regulate metabolism via inter-organ crosstalk. Recent studies have uncovered that BAT produces different PUFA species and circulating oxylipin levels are correlated with BAT-mediated energy expenditure in mice and humans. However, the impact of BAT ω-6/ω-3 PUFAs on metabolic phenotype has not been fully elucidated. The Fat-1 transgenic mice can convert ω-6 to ω-3 PUFAs. Here, we demonstrated that mice receiving Fat-1 BAT transplants displayed better glucose tolerance and higher energy expenditure. Expression of genes involved in thermogenesis and nutrient utilization was increased in the endogenous BAT of mice receiving Fat-1 BAT, suggesting that the transplants may activate recipients’ BAT. Using targeted lipidomic analysis, we found that the levels of several ω-6 oxylipins were significantly reduced in the circulation of mice receiving Fat-1 BAT transplants than in mice with wild-type BAT transplants. The major altered oxylipins between the WT and Fat-1 BAT transplantation were ω-6 arachidonic acid-derived oxylipins via the lipoxygenase pathway. Taken together, these findings suggest an important role of BAT-derived oxylipins in combating obesity-related metabolic disorders.     

Omega-6 Polyunsaturated Fatty Acids Enhance Tumor Aggressiveness in Experimental Lung Cancer Model: Important Role of Oxylipins

Lung cancer is currently the leading cause of cancer death worldwide; it is often diagnosed at an advanced stage and bears poor prognosis. It has been shown that diet is an important environmental factor that contributes to the risk and mortality of several types of cancers. Intake of ω-3 and ω-6 PUFAs plays an important role in cancer risk and progression. Current Western populations have high consumption of ω-6 PUFAs with a ratio of ω-6/ω-3 PUFAs at 15:1 to 16.7:1 This high consumption of ω-6 PUFAs is related to increased cancer risk and progression. However, whether a diet rich in ω-6 PUFAs can contribute to tumor aggressiveness has not been well investigated. We used a murine model of pulmonary squamous cell carcinoma to study the aggressiveness of tumors in mice fed with a diet rich in ω-6 PUFAs and its relationship with oxylipins. Our results shown that the mice fed a diet rich in ω-6 showed a marked increase in proliferation, angiogenesis and pro-inflammatory markers and decreased expression of pro-apoptotic proteins in their tumors. Oxylipin profiling revealed an upregulation of various pro-tumoral oxylipins including PGs, HETEs, DiHETrEs and HODEs. These results demonstrate for the first time that high intake of ω-6 PUFAs in the diet enhances the malignancy of tumor cells by histological changes on tumor dedifferentiation and increases cell proliferation, angiogenesis, pro-inflammatory oxylipins and molecular aggressiveness targets such as NF-κB p65, YY1, COX-2 and TGF-β.     

Maternal PUFA ω-3 Supplementation Prevents Neonatal Lung Injuries Induced by Hyperoxia in Newborn Rats

Bronchopulmonary dysplasia (BPD) is one of the most common complications of prematurity, occurring in 30% of very low birth weight infants. The benefits of dietary intake of polyunsaturated fatty acids ω-3 (PUFA ω-3) during pregnancy or the perinatal period have been reported. The aim of this study was to assess the effects of maternal PUFA ω-3 supplementation on lung injuries in newborn rats exposed to prolonged hyperoxia. Pregnant female Wistar rats (n = 14) were fed a control diet (n = 2), a PUFA ω-6 diet (n = 6), or a PUFA ω-3 diet (n = 6), starting with the 14th gestation day. At Day 1, female and newborn rats (10 per female) were exposed to hyperoxia (O₂, n = 70) or to the ambient air (Air, n = 70). Six groups of newborns rats were obtained: PUFA ω-6/O₂ (n = 30), PUFA ω-6/air (n = 30), PUFA ω-3/O₂ (n = 30), PUFA ω-3/air (n = 30), control/O₂ (n = 10), and control/air (n = 10). After 10 days, lungs were removed for analysis of alveolarization and pulmonary vascular development. Survival rate was 100%. Hyperoxia reduced alveolarization and increased pulmonary vascular wall thickness in both control (n = 20) and PUFA ω-6 groups (n = 60). Maternal PUFA ω-3 supplementation prevented the decrease in alveolarization caused by hyperoxia (n = 30) compared to PUFA ω-6/O₂ (n = 30) or to the control/O₂ (n = 10), but did not significantly increase the thickness of the lung vascular wall. Therefore, maternal PUFA ω-3 supplementation may protect newborn rats from lung injuries induced by hyperoxia. In clinical settings, maternal PUFA ω-3 supplementation during pregnancy and during lactation may prevent BPD development after premature birth.     

Recombinant Integrin β1 Signal Peptide Blocks Gliosis Induced by Aβ Oligomers

Glial cells participate actively in the early cognitive decline in Alzheimer’s disease (AD) pathology. In fact, recent studies have found molecular and functional abnormalities in astrocytes and microglia in both animal models and brains of patients suffering from this pathology. In this regard, reactive gliosis intimately associated with amyloid plaques has become a pathological hallmark of AD. A recent study from our laboratory reports that astrocyte reactivity is caused by a direct interaction between amyloid beta (Aβ) oligomers and integrin β1. Here, we have generated four recombinant peptides including the extracellular domain of integrin β1, and evaluated their capacity both to bind in vitro to Aβ oligomers and to prevent in vivo Aβ oligomer-induced gliosis and endoplasmic reticulum stress. We have identified the minimal region of integrin β1 that binds to Aβ oligomers. This region is called signal peptide and corresponds to the first 20 amino acids of the integrin β1 N-terminal domain. This recombinant integrin β1 signal peptide prevented Aβ oligomer-induced ROS generation in primary astrocyte cultures. Furthermore, we carried out intrahippocampal injection in adult mice of recombinant integrin β1 signal peptide combined with or without Aβ oligomers and we evaluated by immunohistochemistry both astrogliosis and microgliosis as well as endoplasmic reticulum stress. The results show that recombinant integrin β1 signal peptide precluded both astrogliosis and microgliosis and endoplasmic reticulum stress mediated by Aβ oligomers in vivo. We have developed a molecular tool that blocks the activation of the molecular cascade that mediates gliosis via Aβ oligomer/integrin β1 signaling.     

Live Cell FRET Imaging Reveals Amyloid β-Peptide Oligomerization in Hippocampal Neurons

Amyloid β-peptide (Aβ) oligomerization is believed to contribute to the neuronal dysfunction in Alzheimer disease (AD). Despite decades of research, many details of Aβ oligomerization in neurons still need to be revealed. Förster resonance energy transfer (FRET) is a simple but effective way to study molecular interactions. Here, we used a confocal microscope with a sensitive Airyscan detector for FRET detection. By live cell FRET imaging, we detected Aβ42 oligomerization in primary neurons. The neurons were incubated with fluorescently labeled Aβ42 in the cell culture medium for 24 h. Aβ42 were internalized and oligomerized in the lysosomes/late endosomes in a concentration-dependent manner. Both the cellular uptake and intracellular oligomerization of Aβ42 were significantly higher than for Aβ40. These findings provide a better understanding of Aβ42 oligomerization in neurons.     

Impact of Cerebral Amyloid Angiopathy in Two Transgenic Mouse Models of Cerebral β-Amyloidosis: A Neuropathological Study

The pathological accumulation of parenchymal and vascular amyloid-beta (Aβ) are the main hallmarks of Alzheimer’s disease (AD) and Cerebral Amyloid Angiopathy (CAA), respectively. Emerging evidence raises an important contribution of vascular dysfunction in AD pathology that could partially explain the failure of anti-Aβ therapies in this field. Transgenic mice models of cerebral β-amyloidosis are essential to a better understanding of the mechanisms underlying amyloid accumulation in the cerebrovasculature and its interactions with neuritic plaque deposition. Here, our main objective was to evaluate the progression of both parenchymal and vascular deposition in APP23 and 5xFAD transgenic mice in relation to age and sex. We first showed a significant age-dependent accumulation of extracellular Aβ deposits in both transgenic models, with a greater increase in APP23 females. We confirmed that CAA pathology was more prominent in the APP23 mice, demonstrating a higher progression of Aβ-positive vessels with age, but not linked to sex, and detecting a pronounced burden of cerebral microbleeds (cMBs) by magnetic resonance imaging (MRI). In contrast, 5xFAD mice did not present CAA, as shown by the negligible Aβ presence in cerebral vessels and the occurrence of occasional cMBs comparable to WT mice. In conclusion, the APP23 mouse model is an interesting tool to study the overlap between vascular and parenchymal Aβ deposition and to evaluate future disease-modifying therapy before its translation to the clinic.     

The Lack of Amyloidogenic Activity Is Persistent in Old WT and APPswe/PS1ΔE9 Mouse Retinae

We have previously reported that vision decline was not associated with amyloidogenesis processing in aging C57BL/6J wild-type (WT) mice and in a mouse model of Alzheimer’s disease, the APP_swe/PS1ΔE9 transgenic mouse model (APP/PS1). This conclusion was drawn using middle-aged (10–13 months old) mice. Here, we hypothesized that compared with hippocampal and cortical neurons, the weak amyloidogenic activity of retinal neurons may result in a detectable release of amyloid β (Aβ) only in aged mice, i.e., between 14 and 24 months of age. The aim of the present study was thus to follow potential activity changes in the amyloidogenic and nonamyloidogenic pathways of young (4 months) and old (20–24 months) WT and APP/PS1 mice. Our results showed that in spite of retinal activity loss reported by electroretinogram (ERG) recordings, the level of amyloid beta precursor protein (APP) and its derivatives did not significantly vary in the eyes of old vs. young mice. Strikingly, the ectopic expression of human APP_swe in APP/PS1 mice did not allow us to detect Aβ monomers at 23 months. In contrast, Aβ was observed in hippocampal and cortical tissues at this age but not at 4 months of life. In contrast, optic nerve transection-induced retinal ganglion cell injury significantly affected the level of retinal APP and the secretion of soluble APP alpha in the vitreous. Collectively, these results suggest that the amyloidogenic and nonamyloidogenic pathways are not involved in visual function decline in aging mice. In WT and APP/PS1 mice, it is proposed that retinal neurons do not have the capacity to secrete Aβ in contrast with other cortical and hippocampal neurons.     

Propellanes as Rigid Scaffolds for the Stereodefined Attachment of σ-Pharmacophoric Structural Elements to Achieve σ Affinity

Following the concept of conformationally restriction of ligands to achieve high receptor affinity, we exploited the propellane system as rigid scaffold allowing the stereodefined attachment of various substituents. Three types of ligands were designed, synthesized and pharmacologically evaluated as σ₁ receptor ligands. Propellanes with (1) a 2-methoxy-5-methylphenylcarbamate group at the “left” five-membered ring and various amino groups on the “right” side; (2) benzylamino or analogous amino moieties on the “right” side and various substituents at the left five-membered ring and (3) various urea derivatives at one five-membered ring were investigated. The benzylamino substituted carbamate syn,syn-4a showed the highest σ₁ affinity within the group of four stereoisomers emphasizing the importance of the stereochemistry. The cyclohexylmethylamine 18 without further substituents at the propellane scaffold revealed unexpectedly high σ₁ affinity (K_i = 34 nM) confirming the relevance of the bioisosteric replacement of the benzylamino moiety by the cyclohexylmethylamino moiety. Reduction of the distance between the basic amino moiety and the “left” hydrophobic region by incorporation of the amino moiety into the propellane scaffold resulted in azapropellanes with particular high σ₁ affinity. As shown for the propellanamine 18, removal of the carbamate moiety increased the σ₁ affinity of 9a (K_i = 17 nM) considerably. Replacement of the basic amino moiety by H-bond forming urea did not lead to potent σ ligands. According to molecular dynamics simulations, both azapropellanes anti-5 and 9a as well as propellane 18 adopt binding poses at the σ₁ receptor, which result in energetic values correlating well with their different σ₁ affinities. The affinity of the ligands is enthalpy driven. The additional interactions of the carbamate moiety of anti-5 with the σ₁ receptor protein cannot compensate the suboptimal orientations of the rigid propellane and its N-benzyl moiety within the σ₁ receptor-binding pocket, which explains the higher σ₁ affinity of the unsubstituted azapropellane 9a.     

Indomethacin Disrupts the Formation of β-Amyloid Plaques via an α2-Macroglobulin-Activating lrp1-Dependent Mechanism

Epidemiological studies have implied that the nonsteroidal anti-inflammatory drug (NSAID) indomethacin slows the development and progression of Alzheimer’s disease (AD). However, the underlying mechanisms are notably understudied. Using a chimeric mouse/human amyloid precursor protein (Mo/HuAPP695swe) and a mutant human presenilin 1 (PS1-dE9) (APP/PS1) expressing transgenic (Tg) mice and neuroblastoma (N) 2a cells as in vivo and in vitro models, we revealed the mechanisms of indomethacin in ameliorating the cognitive decline of AD. By screening AD-associated genes, we observed that a marked increase in the expression of α₂-macroglobulin (A2M) was markedly induced after treatment with indomethacin. Mechanistically, upregulation of A2M was caused by the inhibition of cyclooxygenase-2 (COX-2) and lipocalin-type prostaglandin D synthase (L-PGDS), which are responsible for the synthesis of prostaglandin (PG)H₂ and PGD₂, respectively. The reduction in PGD₂ levels induced by indomethacin alleviated the suppression of A2M expression through a PGD₂ receptor 2 (CRTH2)-dependent mechanism. Highly activated A2M not only disrupted the production and aggregation of β-amyloid protein (Aβ) but also induced Aβ efflux from the brain. More interestingly, indomethacin decreased the degradation of the A2M receptor, low-density lipoprotein receptor-related protein 1 (LRP1), which facilitated the brain efflux of Aβ. Through the aforementioned mechanisms, indomethacin ameliorated cognitive decline in APP/PS1 Tg mice by decreasing Aβ production and clearing Aβ from the brains of AD mice.     

Protein Kinase C (Pkc)-δ Mediates Arginine-Induced Glucagon Secretion in Pancreatic α-Cells

The pathophysiology of type 2 diabetes involves insulin and glucagon. Protein kinase C (Pkc)-δ, a serine–threonine kinase, is ubiquitously expressed and involved in regulating cell death and proliferation. However, the role of Pkcδ in regulating glucagon secretion in pancreatic α-cells remains unclear. Therefore, this study aimed to elucidate the physiological role of Pkcδ in glucagon secretion from pancreatic α-cells. Glucagon secretions were investigated in Pkcδ-knockdown InR1G9 cells and pancreatic α-cell-specific Pkcδ-knockout (αPkcδKO) mice. Knockdown of Pkcδ in the glucagon-secreting cell line InR1G9 cells reduced glucagon secretion. The basic amino acid arginine enhances glucagon secretion via voltage-dependent calcium channels (VDCC). Furthermore, we showed that arginine increased Pkcδ phosphorylation at Thr⁵⁰⁵, which is critical for Pkcδ activation. Interestingly, the knockdown of Pkcδ in InR1G9 cells reduced arginine-induced glucagon secretion. Moreover, arginine-induced glucagon secretions were decreased in αPkcδKO mice and islets from αPkcδKO mice. Pkcδ is essential for arginine-induced glucagon secretion in pancreatic α-cells. Therefore, this study may contribute to the elucidation of the molecular mechanism of amino acid-induced glucagon secretion and the development of novel antidiabetic drugs targeting Pkcδ and glucagon.     

Circulating Insulin-Like Growth Factor I is Involved in the Effect of High Fat Diet on Peripheral Amyloid β Clearance

Obesity is a risk factor for Alzheimer’s disease (AD), but underlying mechanisms are not clear. We analyzed peripheral clearance of amyloid β (Aβ) in overweight mice because its systemic elimination may impact brain Aβ load, a major landmark of AD pathology. We also analyzed whether circulating insulin-like growth factor I (IGF-I) intervenes in the effects of overweight as this growth factor modulates brain Aβ clearance and is increased in the serum of overweight mice. Overweight mice showed increased Aβ accumulation by the liver, the major site of elimination of systemic Aβ, but unaltered brain Aβ levels. We also found that Aβ accumulation by hepatocytes is stimulated by IGF-I, and that mice with low serum IGF-I levels show reduced liver Aβ accumulation—ameliorated by IGF-I administration, and unchanged brain Aβ levels. In the brain, IGF-I favored the association of its receptor (IGF-IR) with the Aβ precursor protein (APP), and at the same time, stimulated non-amyloidogenic processing of APP in astrocytes, as indicated by an increased sAPPα/sAPPβ ratio after IGF-I treatment. Since serum IGF-I enters into the brain in an activity-dependent manner, we analyzed in overweight mice the effect of brain activation by environmental enrichment (EE) on brain IGF-IR phosphorylation and its association to APP, as a readout of IGF-I activity. After EE, significantly reduced brain IGF-IR phosphorylation and APP/IGF-IR association were found in overweight mice as compared to lean controls. Collectively, these results indicate that a high-fat diet influences peripheral clearance of Aβ without affecting brain Aβ load. Increased serum IGF-I likely contributes to enhanced peripheral Aβ clearance in overweight mice, without affecting brain Aβ load probably because its brain entrance is reduced.     

Characterization of a Mouse Model of Alzheimer’s Disease Expressing Aβ4-42 and Human Mutant Tau

The relationship between the two most prominent neuropathological hallmarks of Alzheimer’s Disease (AD), extracellular amyloid-β (Aβ) deposits and intracellular accumulation of hyperphosphorylated tau in neurofibrillary tangles (NFT), remains at present not fully understood. A large body of evidence places Aβ upstream in the cascade of pathological events, triggering NFTs formation and the subsequent neuron loss. Extracellular Aβ deposits were indeed causative of an increased tau phosphorylation and accumulation in several transgenic models but the contribution of soluble Aβ peptides is still controversial. Among the different Aβ variants, the N-terminally truncated peptide Aβ_4–42 is among the most abundant. To understand whether soluble Aβ_4–42 peptides impact the onset or extent of tau pathology, we have crossed the homozygous Tg4–42 mouse model of AD, exclusively expressing Aβ_4–42 peptides, with the PS19 (P301S) tau transgenic model. Behavioral assessment showed that the resulting double-transgenic line presented a partial worsening of motor performance and spatial memory deficits in the aged group. While an increased loss of distal CA1 pyramidal neurons was detected in young mice, no significant alterations in hippocampal tau phosphorylation were observed in immunohistochemical analyses.     

New Therapeutic Targets for Hepatic Fibrosis in the Integrin Family, α8β1 and α11β1, Induced Specifically on Activated Stellate Cells

A huge effort has been devoted to developing drugs targeting integrins over 30 years, because of the primary roles of integrins in the cell-matrix milieu. Five αv-containing integrins, in the 24 family members, have been a central target of fibrosis. Currently, a small molecule against αvβ1 is undergoing a clinical trial for NASH-associated fibrosis as a rare agent aiming at fibrogenesis. Latent TGFβ activation, a distinct talent of αv-integrins, has been intriguing as a therapeutic target. None of the αv-integrin inhibitors, however, has been in the clinical market. αv-integrins commonly recognize an Arg-Gly-Asp (RGD) sequence, and thus the pharmacophore of inhibitors for the 5-integrins is based on the same RGD structure. The RGD preference of the integrins, at the same time, dilutes ligand specificity, as the 5-integrins share ligands containing RGD sequence such as fibronectin. With the inherent little specificity in both drugs and targets, “disease specificity” has become less important for the inhibitors than blocking as many αv-integrins. In fact, an almighty inhibitor for αv-integrins, pan-αv, was in a clinical trial. On the contrary, approved integrin inhibitors are all specific to target integrins, which are expressed in a cell-type specific manner: αIIbβ3 on platelets, α4β1, α4β7 and αLβ2 on leukocytes. Herein, “disease specific” integrins would serve as attractive targets. α8β1 and α11β1 are selectively expressed in hepatic stellate cells (HSCs) and distinctively induced upon culture activation. The exceptional specificity to activated HSCs reflects a rather “pathology specific” nature of these new integrins. The monoclonal antibodies against α8β1 and α11β1 in preclinical examinations may illuminate the road to the first medical agents.     

An Oligomannuronic Acid-Sialic Acid Conjugate Capable of Inhibiting Aβ42 Aggregation and Alleviating the Inflammatory Response of BV-2 Microglia

Oligomannuronic acid (MOS) from seaweed has antioxidant and anti-inflammatory activities. In this study, MOS was activated at the terminal to obtain three different graft complexes modified with sialic acid moiety (MOS-Sia). The results show that MOS-Sia addition can reduce the β-structure formation of Aβ42, and the binding effect of MOS-Sia3 is more obvious. MOS-Sia conjugates also have a better complexing effect with Ca²⁺ while reducing the formation of Aβ42 oligomers in solutions. MOS-Sia3 (25–50 μg/mL) can effectively inhibit the activation state of BV-2 cells stimulated by Aβ42, whereas a higher dose of MOS-Sia3 (>50 μg/mL) can inhibit the proliferation of BV-2 cells to a certain extent. A lower dose of MOS-Sia3 can also inhibit the expression of IL-1β, IL-6, TNF-α, and other proinflammatory factors in BV-2 cells induced by Aβ42 activation. In the future, the MOS-Sia3 conjugate can be used to treat Alzheimer’s disease.     

Effects of Simvastatin on Lipid Metabolism in Wild-Type Mice and Mice with Muscle PGC-1α Overexpression

Previous studies suggest that statins may disturb skeletal muscle lipid metabolism potentially causing lipotoxicity with insulin resistance. We investigated this possibility in wild-type mice (WT) and mice with skeletal muscle PGC-1α overexpression (PGC-1α OE mice). In WT mice, simvastatin had only minor effects on skeletal muscle lipid metabolism but reduced glucose uptake, indicating impaired insulin sensitivity. Muscle PGC-1α overexpression caused lipid droplet accumulation in skeletal muscle with increased expression of the fatty acid transporter CD36, fatty acid binding protein 4, perilipin 5 and CPT1b but without significant impairment of muscle glucose uptake. Simvastatin further increased the lipid droplet accumulation in PGC-1α OE mice and stimulated muscle glucose uptake. In conclusion, the impaired muscle glucose uptake in WT mice treated with simvastatin cannot be explained by lipotoxicity. PGC-1α OE mice are protected from lipotoxicity of fatty acids and triglycerides by increased the expression of FABP4, formation of lipid droplets and increased expression of CPT1b.     

Korean Red Ginseng Improves Astrocytic Mitochondrial Function by Upregulating HO-1-Mediated AMPKα–PGC-1α–ERRα Circuit after Traumatic Brain Injury

Heme oxygenase-1 (HO-1) exerts beneficial effects, including angiogenesis and energy metabolism via the peroxisome proliferator-activating receptor-γ coactivator-1α (PGC-1α)–estrogen-related receptor α (ERRα) pathway in astrocytes. However, the role of Korean red ginseng extract (KRGE) in HO-1-mediated mitochondrial function in traumatic brain injury (TBI) is not well-elucidated. We found that HO-1 was upregulated in astrocytes located in peri-injured brain regions after a TBI, following exposure to KRGE. Experiments with pharmacological inhibitors and target-specific siRNAs revealed that HO-1 levels highly correlated with increased AMP-activated protein kinase α (AMPKα) activation, which led to the PGC-1α-ERRα axis-induced increases in mitochondrial functions (detected based on expression of cytochrome c oxidase subunit 2 (MTCO2) and cytochrome c as well as O₂ consumption and ATP production). Knockdown of ERRα significantly reduced the p-AMPKα/AMPKα ratio and PGC-1α expression, leading to AMPKα–PGC-1α–ERRα circuit formation. Inactivation of HO by injecting the HO inhibitor Sn(IV) protoporphyrin IX dichloride diminished the expression of p-AMPKα, PGC-1α, ERRα, MTCO2, and cytochrome c in the KRGE-administered peri-injured region of a brain subjected to TBI. These data suggest that KRGE enhanced astrocytic mitochondrial function via a HO-1-mediated AMPKα–PGC-1α–ERRα circuit and consequent oxidative phosphorylation, O₂ consumption, and ATP production. This circuit may play an important role in repairing neurovascular function after TBI in the peri-injured region by stimulating astrocytic mitochondrial biogenesis.     

Wnt/β-Catenin Signalling and Its Cofactor BCL9L Have an Oncogenic Effect in Bladder Cancer Cells

Bladder cancer (BC) is characterised by a high recurrence and progression rate. However, the molecular mechanisms of BC progression remain poorly understood. BCL9L, a coactivator of β-catenin was mutated in the 5′ and 3′ untranslated regions (UTRs). We assessed the influence of UTRs mutations on BCL9L, and the role of BCL9L and Wnt/β-catenin signalling in BC cells. UTR mutations were analysed by a luciferase reporter. BCL9L protein was assessed by immunohistochemistry in BC tissues. Cell proliferation was examined by crystal violet staining and by the spheroid model. Moreover, migration and invasion were analysed in real-time using the xCelligence RTCA system. The A > T mutation at 3′ UTR of BCL9L reduces the luciferase reporter mRNA expression and activity. BCL9L is predominantly increased in dysplastic urothelial cells and muscle-invasive BC. Knockdown of BCL9L and inhibition of Wnt/β-catenin signalling significantly repress the proliferation, migration and invasion of Cal29 and T24. In addition, BCL9L knockdown reduces mRNA level of Wnt/β-catenin target genes in Cal29 but not in T24 cells. BCL9L and Wnt/β-catenin signalling play an oncogenic role in bladder cancer cells and seems to be associated with BC progression. Nevertheless, the involvement of BCL9L in Wnt/β-catenin signalling is cell-line specific.