Blockage of aquaporin-3 peroxiporin activity by organogold compounds affects melanoma cell adhesion, proliferation and migration.

Aquaporin-3 (AQP3) is a membrane channel with dual aquaglyceroporin/peroxiporin activity, facilitating the diffusion of water, glycerol and H2O2 across cell membranes. AQP3 shows aberrant expression in melanoma and its role in cell adhesion, migration and proliferation is well described. Gold compounds were shown to modulate AQP3 activity with reduced associated toxicity, making them promising molecules for cancer therapy. In this study, we validated the phenotype resulting from AQP3-silencing of two melanoma cell lines, MNT-1 and A375, which resulted in decreased H2O2 permeability. Subsequently, the AQP3 inhibitory effect of a new series of organogold compounds derived from Auphen, a potent AQP3 inhibitor, was first evaluated in red blood cells (RBCs) that highly express AQP3, and then in HEK-293T cells with AQP3 overexpression to ascertain the compounds' specificity. The first screening in RBCs unveiled two organogold compounds as promising blockers of AQP3 permeability. Moderate reduction of glycerol permeability but drastic inhibition of H2O2 permeability was detected for some of the gold derivatives in both AQP3-overexpressing cells and human melanoma cell lines. Additionally, all compounds were effective in impairing cell adhesion, proliferation and migration, although in a cell type-dependent manner. In conclusion, our data show that AQP3 peroxiporin activity is crucial for melanoma progression and highlight organogold compounds as promising AQP3 inhibitors with implications in melanoma cell adhesion, proliferation and migration, unveiling their potential as anticancer drugs against AQP3-overexpressing tumours. KEY POINTS: AQP3 affects cellular redox balance. Gold compounds inhibit AQP3 permeability in melanoma cells. AQP3 is involved in cell adhesion, proliferation and migration of melanoma. Blockage of AQP3 peroxiporin activity impairs melanoma cell migration. Gold compounds are potential anticancer drug leads for AQP3-overexpressing cancers.

Cross-platform comparison of immune signatures in immunotherapy-treated patients with advanced melanoma using a rank-based scoring approach.

BACKGROUND: Gene expression profiling is increasingly being utilised as a diagnostic, prognostic and predictive tool for managing cancer patients. Single-sample scoring approach has been developed to alleviate instability of signature scores due to variations from sample composition. However, it is a challenge to achieve comparable signature scores across different expressional platforms. METHODS: The pre-treatment biopsies from a total of 158 patients, who have received single-agent anti-PD-1 (n = 84) or anti-PD-1 + anti-CTLA-4 therapy (n = 74), were performed using NanoString PanCancer IO360 Panel. Multiple immune-related signature scores were measured from a single-sample rank-based scoring approach, singscore. We assessed the reproducibility and the performance in reporting immune profile of singscore based on NanoString assay in advance melanoma. To conduct cross-platform analyses, singscores between the immune profiles of NanoString assay and the previous orthogonal whole transcriptome sequencing (WTS) data were compared through linear regression and cross-platform prediction. RESULTS: singscore-derived signature scores reported significantly high scores in responders in multiple PD-1, MHC-1-, CD8 T-cell-, antigen presentation-, cytokine- and chemokine-related signatures. We found that singscore provided stable and reproducible signature scores among the repeats in different batches and cross-sample normalisations. The cross-platform comparisons confirmed that singscores derived via NanoString and WTS were comparable. When singscore of WTS generated by the overlapping genes to the NanoString gene set, the signatures generated highly correlated cross-platform scores (Spearman correlation interquartile range (IQR) [0.88, 0.92] and r2 IQR [0.77, 0.81]) and better prediction on cross-platform response (AUC = 86.3%). The model suggested that Tumour Inflammation Signature (TIS) and Personalised Immunotherapy Platform (PIP) PD-1 are informative signatures for predicting immunotherapy-response outcomes in advanced melanoma patients treated with anti-PD-1-based therapies. CONCLUSIONS: Overall, the outcome of this study confirms that singscore based on NanoString data is a feasible approach to produce reliable signature scores for determining patients' immune profiles and the potential clinical utility in biomarker implementation, as well as to conduct cross-platform comparisons, such as WTS.

Chemotherapy in Cutaneous Melanoma: Is There Still a Role?

PURPOSE OF REVIEW: In the preceding decade, the management of metastatic cutaneous melanoma has been revolutionised with the development of highly effective therapies including immune checkpoint inhibitors (specifically CTLA-4 and PD-1 inhibitors) and targeted therapies (BRAF and MEK inhibitors). The role of chemotherapy in the contemporary management of melanoma is undefined. RECENT FINDINGS: Extended analyses highlight substantially improved 5-year survival rates of approximately 50% in patients with metastatic melanoma treated with first-line therapies. However, most patients will progress on these first-line treatments. Sequencing of chemotherapy following failure of targeted and immunotherapies is associated with low objective response rates and short progression-free survival, and thus, meaningful benefits to patients are minimal. Chemotherapy has limited utility in the contemporary management of cutaneous melanoma (with a few exceptions, discussed herein) and should not be the standard treatment sequence following failure of first-line therapies. Instead, enrolment onto clinical trials should be standard-of-care in these patients.

Aquaporins in Obesity.

Obesity is one of the most important metabolic disorders of this century and is associated with a cluster of the most dangerous cardiovascular disease risk factors, such as insulin resistance and diabetes, dyslipidemia, and hypertension, collectively named Metabolic Syndrome. The role of aquaporins (AQP) in glycerol metabolism facilitating glycerol release from the adipose tissue and distribution to various tissues and organs unveils these membrane channels as important players in lipid balance and energy homeostasis and points to their involvement in a variety of pathophysiological mechanisms including insulin resistance, obesity, and diabetes. This review summarizes the physiologic role of aquaglyceroporins in glycerol metabolism and lipid homeostasis, describing their specific tissue distribution, involvement in glycerol balance, and implication in obesity and fat-related metabolic complications. The development of specify pharmacologic modulators able to regulate aquaglyceroporins expression and function, in particular AQP7 in adipose tissue, might constitute a novel approach for controlling obesity and other metabolic disorders.

Small-Cell Lung Cancer-An Update on Targeted and Immunotherapies.

Small-cell lung cancer (SCLC) is an aggressive disease with distinct biological and clinical features. The clinical course of SCLC is generally characterised by initial sensitivity to DNA-damaging therapies, followed by early relapse and broad cross resistance to second line agents. Whilst there has been an enormous expansion of effective targeted and immune-based therapeutic options for non-small cell lung cancer (NSCLC) in the last decade, little improvement has been achieved in SCLC treatment and survival due, at least in part, to underappreciated inter- and intra-tumoral heterogeneity. Here we review the current treatment paradigm of SCLC including recent advances made in utilizing immunotherapy and the challenges of identifying a predictive biomarker for immunotherapy response. We examine emerging new targeted therapies, combination immunotherapy and future directions of SCLC treatment research.

AQP3-Dependent PI3K/Akt Modulation in Breast Cancer Cells.

Aquaporin 3 (AQP3) is a peroxiporin, a membrane protein that channels hydrogen peroxide in addition to water and glycerol. AQP3 expression also correlates with tumor progression and malignancy and is, therefore, a potential target in breast cancer therapy. In addition, epithelial growth factor receptor (EGFR) plays an important role in breast cancer. Therefore, we investigated whether disruption of the lipid raft harboring EGFR could affect AQP3 expression, and conversely, whether AQP3 silencing would affect the EGFR/phosphoinositide-3-kinase (PI3K)/Protein kinase B (PKB or Akt) signaling pathway in breast cancer cell lines with different malignant capacities. We evaluated H2O2 uptake, cell migratory capacity, and expression of PI3K, pAkt/Akt in three breast cancer cell lines, MCF7, SkBr3, and SUM159PT, and in the nontumorigenic breast epithelial cell line MCF10A. Our results show different responses between the tested cell lines, especially when compared to the nontumorigenic cell line. Neither lipid raft disruption nor EGF stimuli had an effect on PI3K/Akt pathway in MCF10A cell line. AQP3-silencing in SkBr3 and SUM159PT showed that AQP3 can modulate PI3K/Akt activation in these cells. Interestingly, SUM159PT cells increase nuclear factor-E2-related factor 2 (NRF2) in response to lipid raft disruption and EGF stimuli, suggesting an oxidative-dependent response to these treatments. These results suggest that in breast cancer cell lines, AQP3 is not directly related to PI3K/Akt pathway but rather in a cell-line-dependent manner.

Increased Aquaporin-7 Expression Is Associated with Changes in Rat Brown Adipose Tissue Whitening in Obesity: Impact of Cold Exposure and Bariatric Surgery.

Glycerol is a key metabolite for lipid accumulation in insulin-sensitive tissues. We examined the role of aquaporin-7 (AQP7), the main glycerol channel in adipocytes, in the improvement of brown adipose tissue (BAT) whitening, a process whereby brown adipocytes differentiate into white-like unilocular cells, after cold exposure or bariatric surgery in male Wistar rats with diet-induced obesity (DIO) (n = 229). DIO promoted BAT whitening, evidenced by increased BAT hypertrophy, steatosis and upregulation of the lipogenic factors Pparg2, Mogat2 and Dgat1. AQP7 was detected in BAT capillary endothelial cells and brown adipocytes, and its expression was upregulated by DIO. Interestingly, AQP7 gene and protein expressions were downregulated after cold exposure (4 °C) for 1 week or one month after sleeve gastrectomy in parallel to the improvement of BAT whitening. Moreover, Aqp7 mRNA expression was positively associated with transcripts of the lipogenic factors Pparg2, Mogat2 and Dgat1 and regulated by lipogenic (ghrelin) and lipolytic (isoproterenol and leptin) signals. Together, the upregulation of AQP7 in DIO might contribute to glycerol influx used for triacylglycerol synthesis in brown adipocytes, and hence, BAT whitening. This process is reversible by cold exposure and bariatric surgery, thereby suggesting the potential of targeting BAT AQP7 as an anti-obesity therapy.

Aquaporin-3 is involved in NLRP3-inflammasome activation contributing to the setting of inflammatory response.

Inflammasomes are large immune multiprotein complexes that tightly regulate the production of the pro-inflammatory cytokines, being dependent on cell regulatory volume mechanisms. Aquaporins (AQPs) are protein channels that facilitate the transport of water and glycerol (aquaglyceroporins) through membranes, essential for cell volume regulation. Although these membrane proteins are highly expressed in monocytes and macrophages, their role in the inflammatory process is still unclear. Here, we investigated the role of aquaglyceroporin AQP3 in NLRP3-inflammasome activation by complementary approaches based either on shRNA silencing or on AQP3 selective inhibition. The latter has been achieved using a reported potent gold-based inhibitor, Auphen. AQP3 inhibition or silencing partially blocked LPS-priming and decreased production of IL-6, proIL-1ß, and TNF-α, suggesting the possible involvement of AQP3 in macrophage priming by Toll-like receptor 4 engagement. Moreover, AQP3-dependent cell reswelling increased IL-1ß release through caspase-1 activation. NLRP3-inflammasome activation induced by reswelling, nigericin, and ATP was also blocked when AQP3 was inhibited or silenced. Altogether, these data point towards AQPs as potential players in the setting of the inflammatory response.

Ipilimumab alone or ipilimumab plus anti-PD-1 therapy in patients with metastatic melanoma resistant to anti-PD-(L)1 monotherapy: a multicentre, retrospective, cohort study.

BACKGROUND: Anti-PD-1 therapy (hereafter referred to as anti-PD-1) induces long-term disease control in approximately 30% of patients with metastatic melanoma; however, two-thirds of patients are resistant and will require further treatment. We aimed to determine the efficacy and safety of ipilimumab plus anti-PD-1 (pembrolizumab or nivolumab) compared with ipilimumab monotherapy in patients who are resistant to anti-PD-(L)1 therapy (hereafter referred to as anti-PD-[L]1). METHODS: This multicentre, retrospective, cohort study, was done at 15 melanoma centres in Australia, Europe, and the USA. We included adult patients (aged ≥18 years) with metastatic melanoma (unresectable stage III and IV), who were resistant to anti-PD-(L)1 (innate or acquired resistance) and who then received either ipilimumab monotherapy or ipilimumab plus anti-PD-1 (pembrolizumab or nivolumab), based on availability of therapies or clinical factors determined by the physician, or both. Tumour response was assessed as per standard of care (CT or PET-CT scans every 3 months). The study endpoints were objective response rate, progression-free survival, overall survival, and safety of ipilimumab compared with ipilimumab plus anti-PD-1. FINDINGS: We included 355 patients with metastatic melanoma, resistant to anti-PD-(L)1 (nivolumab, pembrolizumab, or atezolizumab), who had been treated with ipilimumab monotherapy (n=162 [46%]) or ipilimumab plus anti-PD-1 (n=193 [54%]) between Feb 1, 2011, and Feb 6, 2020. At a median follow-up of 22·1 months (IQR 9·5-30·9), the objective response rate was higher with ipilimumab plus anti-PD-1 (60 [31%] of 193 patients) than with ipilimumab monotherapy (21 [13%] of 162 patients; p<0·0001). Overall survival was longer in the ipilimumab plus anti-PD-1 group (median overall survival 20·4 months [95% CI 12·7-34·8]) than with ipilimumab monotherapy (8·8 months [6·1-11·3]; hazard ratio [HR] 0·50, 95% CI 0·38-0·66; p<0·0001). Progression-free survival was also longer with ipilimumab plus anti-PD-1 (median 3·0 months [95% CI 2·6-3·6]) than with ipilimumab (2·6 months [2·4-2·9]; HR 0·69, 95% CI 0·55-0·87; p=0·0019). Similar proportions of patients reported grade 3-5 adverse events in both groups (59 [31%] of 193 patients in the ipilimumab plus anti-PD-1 group vs 54 [33%] of 162 patients in the ipilimumab group). The most common grade 3-5 adverse events were diarrhoea or colitis (23 [12%] of 193 patients in the ipilimumab plus anti-PD-1 group vs 33 [20%] of 162 patients in the ipilimumab group) and increased alanine aminotransferase or aspartate aminotransferase (24 [12%] vs 15 [9%]). One death occurred with ipilimumab 26 days after the last treatment: a colon perforation due to immune-related pancolitis. INTERPRETATION: In patients who are resistant to anti-PD-(L)1, ipilimumab plus anti-PD-1 seemed to yield higher efficacy than ipilimumab with a higher objective response rate, longer progression-free, and longer overall survival, with a similar rate of grade 3-5 toxicity. Ipilimumab plus anti-PD-1 should be favoured over ipilimumab alone as a second-line immunotherapy for these patients with advanced melanoma. FUNDING: None.

Beyond faith: Biomolecular evidence for changing urban economies in multi-faith medieval Portugal.

OBJECTIVES: During the Middle Ages, Portugal witnessed unprecedented socioeconomic and religious changes under transitioning religious political rule. The implications of changing ruling powers for urban food systems and individual diets in medieval Portugal is poorly understood. This study aimed to elucidate the dietary impact of the Islamic and Christian conquests. MATERIALS AND METHODS: Radiocarbon dating, peptide mass fingerprinting (ZooMS) and stable isotope analysis (δ13 C, δ15 N) of animal (n = 59) and human skeletal remains (n = 205) from Muslim and Christian burials were used to characterize the diet of a large historical sample from Portugal. A Bayesian stable isotope mixing model (BSIMM) was used to estimate the contribution of marine protein to human diet. RESULTS: Early medieval (8-12th century), preconquest urban Muslim populations had mean (±1SD) values of -18.8 ± 0.4 ‰ for δ13 C 10.4 ± 1 ‰ for δ15 N, indicating a predominantly terrestrial diet, while late medieval (12-14th century) postconquest Muslim and Christian populations showed a greater reliance on marine resources with mean (±1SD) values of -17.9 ± 1.3‰ for δ13 C and 11.1 ± 1.1‰ for δ15 N. BSIMM estimation supported a significant increase in the contribution of marine resources to human diet. DISCUSSION: The results provide the first biomolecular evidence for a dietary revolution that is not evidenced in contemporaneous historical accounts. We find that society transitioned from a largely agro-pastoral economy under Islamic rule to one characterized by a new focus on marine resources under later Christian rule. This economic change led to the naissance of the marine economy that went on to characterize the early-modern period in Portugal and its global expansion.

Aquaporins in Immune Cells and Inflammation: New Targets for Drug Development.

The mammalian immune system senses foreign antigens by mechanisms that involve the interplay of various kinds of immune cells, culminating in inflammation resolution and tissue clearance. The ability of the immune cells to communicate (via chemokines) and to shift shape for migration, phagocytosis or antigen uptake is mainly supported by critical proteins such as aquaporins (AQPs) that regulate water fluid homeostasis and volume changes. AQPs are protein channels that facilitate water and small uncharged molecules' (such as glycerol or hydrogen peroxide) diffusion through membranes. A number of AQP isoforms were found upregulated in inflammatory conditions and are considered essential for the migration and survival of immune cells. The present review updates information on AQPs' involvement in immunity and inflammatory processes, highlighting their role as crucial players and promising targets for drug discovery.

Site-specific response patterns, pseudoprogression, and acquired resistance in patients with melanoma treated with ipilimumab combined with anti-PD-1 therapy.

BACKGROUND: Patients with metastatic melanoma have variable responses to combination ipilimumab and nivolumab. The objectives of this study were to examine the patterns of response and survival in patients treated with combination ipilimumab and anti-PD-1 therapy (IPI + PD1) and to explore the nature of pseudoprogression and acquired resistance. METHODS: Patients with metastatic melanoma who received treatment with first-line IPI + PD1 had all metastases ≥5 mm measured on computed tomography/magnetic resonance imaging studies. The lesional response rate (LRR) and the overall response rate (ORR) were determined according to Response Evaluation Criteria in Solid Tumors, version 1.1. RESULTS: In total, 140 patients who had 833 metastases were studied. The ORR and the overall complete response (CR) rate decreased as tumor burden or the number of metastases increased. Metastases that had a CR (49%) were smaller than metastases without a CR (median, 13 vs 17 mm; P < .0001). Soft-tissue and lung metastases had the highest LRR (79% and 77%, respectively), whereas liver metastases had the lowest (46%). In multivariate analysis, patients with lung metastases had superior ORR (odds ratio [OR], 2.75; P = .02) and progression-free survival (hazard ratio [HR], 0.46; P = .02), whereas those with liver metastases had inferior ORR (OR, 0.33; P = .02), progression-free survival (HR, 4.03; P < .01), and overall survival (HR, 3.17; P = .01). Pseudoprogression occurred in one-third of patients who had progressive disease as their best response, with an overall survival that was comparable to that of patients without disease progression. Acquired resistance occurred in 12% of responders after a median of 9.6 months, with an overall survival rate of 83% at 1 year from progression. CONCLUSIONS: Metastases in different anatomical locations display distinct response patterns and also are associated with overall response and survival with combination immunotherapy. Specific sites of disease may hold unique mechanisms of resistance and should allow for more personalized treatment.

Aquaporin-7 and aquaporin-12 modulate the inflammatory phenotype of endocrine pancreatic beta-cells.

Aquaporins (AQPs) facilitate water and glycerol movement across membranes. AQP7 is the main aquaglyceroporin in pancreatic ß-cells and was proposed to play a role in insulin exocytosis. Although AQP7-null mice display adult-onset obesity, impaired insulin secretion and insulin resistance, AQP7 loss-of-function homozygous mutations in humans do not correlate with obesity nor type-2 diabetes. In addition, AQP12 is upregulated in pancreatitis. However, the implication of this isoform in endocrine pancreas inflammation is still unclear. Here, we investigated AQP7 and AQP12 involvement in cellular and inflammatory processes using RIN-m5F beta cells, a model widely used for their high insulin secretion. AQP7 and AQP12 expression were directly associated with cell proliferation, adhesion and migration. While tumor necrosis factor-alpha (TNFα)-induced inflammation impaired AQP7 expression and drastically reduced insulin secretion, lipopolysaccharides (LPS) prompted AQP7 upregulation, and both TNFα and LPS upregulated AQP12. Importantly, cells overexpressing AQP12 are more resistant to inflammation, revealing lower levels of proinflammatory markers. Altogether, these data document AQP7 involvement in insulin secretion and AQP12 implication in inflammation, highlighting their fundamental role in pancreatic ß-cell function.

Aquaglyceroporins Are Differentially Expressed in Beige and White Adipocytes.

Browning of white adipocytes has been proposed as a powerful strategy to overcome metabolic complications, since brown adipocytes are more catabolic, expending energy as a heat form. However, the biological pathways involved in the browning process are still unclear. Aquaglyceroporins are a sub-class of aquaporin water channels that also permeate glycerol and are involved in body energy homeostasis. In the adipose tissue, aquaporin-7 (AQP7) is the most representative isoform, being crucial for white adipocyte fully differentiation and glycerol metabolism. The altered expression of AQP7 is involved in the onset of obesity and metabolic disorders. Herein, we investigated if aquaglyceroporins are implicated in beige adipocyte differentiation, similar to white cells. Thus, we optimized a protocol of murine 3T3-L1 preadipocytes browning that displayed increased beige and decreased white adipose tissue features at both gene and protein levels and evaluated aquaporin expression patterns along the differentiation process together with cellular lipid content. Our results revealed that AQP7 and aquaporin-9 (AQP9) expression was downregulated throughout beige adipocyte differentiation compared to white differentiation, which may be related to the beige physiological role of heat production from oxidative metabolism, contrasting with the anabolic/catabolic lipid metabolism requiring glycerol gateways occurring in white adipose cells.

The Aquaporin-3-Inhibiting Potential of Polyoxotungstates.

Polyoxometalates (POMs) are of increasing interest due to their proven anticancer activities. Aquaporins (AQPs) were found to be overexpressed in tumors bringing particular attention to their inhibitors as anticancer drugs. Herein, we report for the first time the ability of polyoxotungstates (POTs), such as of Wells-Dawson P2W18, P2W12, and P2W15, and Preyssler P5W30 structures, to affect aquaporin-3 (AQP3) activity and impair melanoma cell migration. The tested POTs were revealed to inhibit AQP3 function with different effects, with P2W18, P2W12, and P5W30 being the most potent (50% inhibitory concentration (IC50) = 0.8, 2.8, and 3.2 µM), and P2W15 being the weakest (IC50 > 100 µM). The selectivity of P2W18 toward AQP3 was confirmed in yeast cells transformed with human aquaglyceroporins. The effect of P2W12 and P2W18 on melanoma cells that highly express AQP3 revealed an impairment of cell migration between 55% and 65% after 24 h, indicating that the anticancer properties of these compounds may in part be due to the blockage of AQP3-mediated permeability. Altogether, our data revealed that P2W18 strongly affects AQP3 activity and cancer cell growth, unveiling its potential as an anticancer drug against tumors where AQP3 is highly expressed.

Revisiting the metabolic syndrome: the emerging role of aquaglyceroporins.

The metabolic syndrome (MetS) includes a group of medical conditions such as insulin resistance (IR), dyslipidemia and hypertension, all associated with an increased risk for cardiovascular disease. Increased visceral and ectopic fat deposition are also key features in the development of IR and MetS, with pathophysiological sequels on adipose tissue, liver and muscle. The recent recognition of aquaporins (AQPs) involvement in adipose tissue homeostasis has opened new perspectives for research in this field. The members of the aquaglyceroporin subfamily are specific glycerol channels implicated in energy metabolism by facilitating glycerol outflow from adipose tissue and its systemic distribution and uptake by liver and muscle, unveiling these membrane channels as key players in lipid balance and energy homeostasis. Being involved in a variety of pathophysiological mechanisms including IR and obesity, AQPs are considered promising drug targets that may prompt novel therapeutic approaches for metabolic disorders such as MetS. This review addresses the interplay between adipose tissue, liver and muscle, which is the basis of the metabolic syndrome, and highlights the involvement of aquaglyceroporins in obesity and related pathologies and how their regulation in different organs contributes to the features of the metabolic syndrome.

Modulation of aquaporin gene expression by n-3 long-chain PUFA lipid structures in white and brown adipose tissue from hamsters.

EPA (20 : 5n-3) and DHA (22 : 6n-3) fatty acids have weight-reducing properties with physiological activity depending on their molecular structure - that is, as TAG or ethyl esters (EE). Aquaporins (AQP) are membrane protein channels recognised as important players in fat metabolism, but their differential expression in white adipose tissue (WAT) and brown adipose tissue (BAT), as well as their modulation by dietary n-3 long-chain PUFA (LCPUFA) such as EPA and DHA, has never been investigated. In this study, the transcriptional profiles of AQP3, AQP5, AQP7 and selected lipid markers of WAT (subcutaneous and visceral) and BAT (interscapular) from hamsters fed diets containing n-3 LCPUFA in different lipid structures such as fish oil (FO, rich in EPA and DHA in the TAG form) and FO-EE (rich in EPA and DHA in the EE form) were used and compared with linseed oil (LSO) as the reference group. A clear effect of fat depot was observed for AQP3 and leptin (LEP), with the lowest values of mRNA found in BAT relative to WAT. The opposite occurred for PPARα. AQP7 was affected by diet, with FO-fed hamsters having higher mRNA levels compared with LSO-fed hamsters. The relative gene expression of AQP5, adiponectin (ADIPO), GLUT4 and PPARγ was influenced by both fat tissue and diet. Taken together, our results revealed a differential expression profile of AQP and some markers of lipid metabolism in both WAT and BAT in response to feeding n-3 LCPUFA in two different structural formats: TAG v. EE.

Endothelial Aquaporins and Hypomethylation: Potential Implications for Atherosclerosis and Cardiovascular Disease.

Aquaporins (AQPs) are transmembrane channels that facilitate water and glycerol permeation through cell membranes. Recently, the water channel AQP1 was suggested to contribute to endothelial homeostasis and cardiovascular health. Less is known about endothelial aquaglyceroporins expression and its implication in cardiovascular disease (CVD). We have previously used cultured human endothelial cells under a hypomethylating environment to study endothelial dysfunction and activation, a phenotype implicated in the establishment of atherosclerosis and CVD. Here, we used the same cell model to investigate aquaporin's expression and function in healthy or pro-atherogenic phenotype. We first confirmed key features of endothelium dysfunction and activation in our cell model, including an augmented endothelial transmigration under hypomethylation. Subsequently, we found AQP1 and AQP3 to be the most predominant AQPs accounting for water and glycerol fluxes, respectively, in the healthy endothelium. Moreover, endothelial hypomethylation led to decreased levels of AQP1 and impaired water permeability without affecting AQP3 and glycerol permeability. Furthermore, TNF-α treatment-induced AQP1 downregulation suggesting that the inflammatory NF-κB signaling pathway mediates AQP1 transcriptional repression in a pro-atherogenic endothelium, a possibility that warrants further investigation. In conclusion, our results add further support to AQP1 as a candidate player in the setting of endothelial dysfunction and CVD.