Aquaporins Involvement in Pancreas Physiology and in Pancreatic Diseases

Stellate cells are in utero markers of pancreatic disease in cystic fibrosis

BACKGROUND

Pancreatic fibrosis is an early diagnostic feature of the common inherited disorder cystic fibrosis (CF). Many people with CF (pwCF) are pancreatic insufficient from birth and the replacement of acinar tissue with cystic lesions and fibrosis is a progressive phenotype that may later lead to diabetes. Little is known about the initiating events in the fibrotic process though it may be a sequela of inflammation in the pancreatic ducts resulting from loss of CFTR impairing normal fluid secretion. Here we use a sheep model of CF (CFTR-/-) to examine the evolution of pancreatic disease through gestation.

METHODS

Fetal pancreas was collected at six time points from 50-days of gestation through to term, which is equivalent to ~ 13 weeks to term in human. RNA was extracted from tissue for bulk RNA-seq and single cells were prepared from 80-day, 120-day and term samples for scRNA-seq. Data were validated by immunochemistry.

RESULTS

Transcriptomic evidence from bulk RNA-seq showed alterations in the CFTR-/- pancreas by 65-days of gestation, which are accompanied by marked pathological changes by 80-days of gestation. These include a fibrotic response, confirmed by immunostaining for COL1A1, αSMA and SPARC, together with acinar loss. Moreover, using scRNA-seq we identify a unique cell population that is significantly overrepresented in the CFTR-/- animals at 80- and 120-days gestation, as are stellate cells at term.

CONCLUSION

The transcriptomic changes and cellular imbalance that we observe likely have pivotal roles in the evolution of CF pancreatic disease and may provide therapeutic opportunities to delay or prevent pancreatic destruction in CF.

Metabolic heterogeneity in tumor microenvironment - A novel landmark for immunotherapy

The surrounding non-cancer cells and tumor cells that make up the tumor microenvironment (TME) have various metabolic rhythms. TME metabolic heterogeneity is influenced by the intricate network of metabolic control within and between cells. DNA, protein, transport, and microbial levels are important regulators of TME metabolic homeostasis. The effectiveness of immunotherapy is also closely correlated with alterations in TME metabolism. The response of a tumor patient to immunotherapy is influenced by a variety of variables, including intracellular metabolic reprogramming, metabolic interaction between cells, ecological changes within and between tumors, and general dietary preferences. Although immunotherapy and targeted therapy have made great strides, their use in the accurate identification and treatment of tumors still has several limitations. The function of TME metabolic heterogeneity in tumor immunotherapy is summarized in this article. It focuses on how metabolic heterogeneity develops and is regulated as a tumor progresses, the precise molecular mechanisms and potential clinical significance of imbalances in intracellular metabolic homeostasis and intercellular metabolic coupling and interaction, as well as the benefits and drawbacks of targeted metabolism used in conjunction with immunotherapy. This offers insightful knowledge and important implications for individualized tumor patient diagnosis and treatment plans in the future.

Polyethersulfone Polymer for Biomedical Applications and Biotechnology

Polymers stand out as promising materials extensively employed in biomedicine and biotechnology. Their versatile applications owe much to the field of tissue engineering, which seamlessly integrates materials engineering with medical science. In medicine, biomaterials serve as prototypes for organ development and as implants or scaffolds to facilitate body regeneration. With the growing demand for innovative solutions, synthetic and hybrid polymer materials, such as polyethersulfone, are gaining traction. This article offers a concise characterization of polyethersulfone followed by an exploration of its diverse applications in medical and biotechnological realms. It concludes by summarizing the significant roles of polyethersulfone in advancing both medicine and biotechnology, as outlined in the accompanying table.

Pancreatic Crosstalk in the Disease Setting: Understanding the Impact of Exocrine Disease on Endocrine Function

The exocrine and endocrine are functionally distinct compartments of the pancreas that have traditionally been studied as separate entities. However, studies of embryonic development, adult physiology, and disease pathogenesis suggest there may be critical communication between exocrine and endocrine cells. In fact, the incidence of the endocrine disease diabetes secondary to exocrine disease/dysfunction ranges from 25% to 80%, depending on the type and severity of the exocrine pathology. Therefore, it is necessary to investigate how exocrine-endocrine "crosstalk" may impact pancreatic function. In this article, we discuss common exocrine diseases, including cystic fibrosis, acute, hereditary, and chronic pancreatitis, and the impact of these exocrine diseases on endocrine function. Additionally, we review how obesity and fatty pancreas influence exocrine function and the impact on cellular communication between the exocrine and endocrine compartments. Interestingly, in all pathologies, there is evidence that signals from the exocrine disease contribute to endocrine dysfunction and the progression to diabetes. Continued research efforts to identify the mechanisms that underlie the crosstalk between various cell types in the pancreas are critical to understanding normal pancreatic physiology as well as disease states. © 2024 American Physiological Society. Compr Physiol 14:5371-5387, 2024.

Insights into the Function of Aquaporins in Gastrointestinal Fluid Absorption and Secretion in Health and Disease

Aquaporins (AQPs), transmembrane proteins permeable to water, are involved in gastrointestinal secretion. The secretory products of the glands are delivered either to some organ cavities for exocrine glands or to the bloodstream for endocrine glands. The main secretory glands being part of the gastrointestinal system are salivary glands, gastric glands, duodenal Brunner's gland, liver, bile ducts, gallbladder, intestinal goblet cells, exocrine and endocrine pancreas. Due to their expression in gastrointestinal exocrine and endocrine glands, AQPs fulfill important roles in the secretion of various fluids involved in food handling. This review summarizes the contribution of AQPs in physiological and pathophysiological stages related to gastrointestinal secretion.

Aquaporins Transcripts with Potential Prognostic Value in Pancreatic Cancer

Pancreatic cancer is anticipated to be the second leading cause of cancer-related death by 2030. Aquaporins (AQPs), a family of water channel proteins, have been linked to carcinogenesis. The aim of this study was to determine AQP gene expression in pancreatic cancer tissues and to validate aquaporins as possible diagnosis and/or prognosis genes. The relative gene expression levels of AQP1, AQP3, AQP5, and AQP9 were analyzed using real-time quantitative PCR (RT-qPCR) in 24 paired pancreatic tumors and adjacent healthy tissues according to variables such as age, gender, and tumor invasiveness and aggressiveness. AQPs transcripts were detected in both healthy and tumor tissues. While AQP1 was downregulated in the tumor samples, AQP3 was particularly overexpressed in low-grade invasive tumors. Interestingly, most of the strong positive Pearson correlation coefficients found between AQPs in healthy tissues were lost when analyzing the tumor tissues, suggesting disruption of the coordinated AQP-gene expression in pancreatic cancer.

Analysis of Donor Pancreata Defines the Transcriptomic Signature and Microenvironment of Early Neoplastic Lesions

The adult healthy human pancreas has been poorly studied given the lack of indication to obtain tissue from the pancreas in the absence of disease and rapid postmortem degradation. We obtained pancreata from brain dead donors, thus avoiding any warm ischemia time. The 30 donors were diverse in age and race and had no known pancreas disease. Histopathologic analysis of the samples revealed pancreatic intraepithelial neoplasia (PanIN) lesions in most individuals irrespective of age. Using a combination of multiplex IHC, single-cell RNA sequencing, and spatial transcriptomics, we provide the first-ever characterization of the unique microenvironment of the adult human pancreas and of sporadic PanIN lesions. We compared healthy pancreata to pancreatic cancer and peritumoral tissue and observed distinct transcriptomic signatures in fibroblasts and, to a lesser extent, macrophages. PanIN epithelial cells from healthy pancreata were remarkably transcriptionally similar to cancer cells, suggesting that neoplastic pathways are initiated early in tumorigenesis.

SIGNIFICANCE

Precursor lesions to pancreatic cancer are poorly characterized. We analyzed donor pancreata and discovered that precursor lesions are detected at a much higher rate than the incidence of pancreatic cancer, setting the stage for efforts to elucidate the microenvironmental and cell-intrinsic factors that restrain or, conversely, promote malignant progression. See related commentary by Hoffman and Dougan, p. 1288. This article is highlighted in the In This Issue feature, p. 1275.

Correlation between Pancreatic Duct Variation and Related Diseases: An Effective Method Observing the Dual-Energy CT with Low-keV Monoenergetic Images

PURPOSE

Pancreatic duct variation can affect the secretory function of the pancreas. We aimed to explore the pancreatic duct variation, observed using low-keV monoenergetic images [MEI (+)] of dual-energy CT (DECT), and its relationship with related diseases. We further sought to compare pancreatic duct imaging using low-keV MEI (+) of DECT and magnetic resonance cholangiopancreatography (MRCP).

MATERIALS AND METHODS

The DECT and MRCP images of 854 patients were evaluated retrospectively. The 808 patients' pancreatic duct types were classified according to the anatomy and the opening of the pancreatic ducts, and the correlation with related diseases was analyzed. The DECT and MRCP images of 852 patients were graded according to the sharpness of the pancreatic ducts for evaluation.

RESULTS

A higher prevalence of acute pancreatitis (AP), chronic pancreatitis (CP), and duodenal papillary carcinoma (DPC) was observed in the variant group. Of the 27 AP cases in the variant group, 9 patients (33.3%) were Type 3c. Additionally, Type 4a was significantly correlated with AP and CP (p < 0.05). Low-keV MEI (+) of DECT outperformed the MRCP images in the sharpness of the pancreatic ducts in 852 patients.

CONCLUSIONS

Pancreatic duct variation is associated with AP, CP, and DPC. Low-keV MEI (+) DECT is an effective method to observe the pancreatic duct system.

Analysis of donor pancreata defines the transcriptomic signature and microenvironment of early pre-neoplastic pancreatic lesions

The adult healthy human pancreas has been poorly studied given lack of indication to obtain tissue from the pancreas in the absence of disease and rapid postmortem degradation. We obtained pancreata from brain dead donors thus avoiding any warm ischemia time. The 30 donors were diverse in age and race and had no known pancreas disease. Histopathological analysis of the samples revealed PanIN lesions in most individuals irrespective of age. Using a combination of multiplex immunohistochemistry, single cell RNA sequencing, and spatial transcriptomics, we provide the first ever characterization of the unique microenvironment of the adult human pancreas and of sporadic PanIN lesions. We compared healthy pancreata to pancreatic cancer and peritumoral tissue and observed distinct transcriptomic signatures in fibroblasts, and, to a lesser extent, macrophages. PanIN epithelial cells from healthy pancreata were remarkably transcriptionally similar to cancer cells, suggesting that neoplastic pathways are initiated early in tumorigenesis.

Statement of significance

The causes underlying the onset of pancreatic cancer remain largely unknown, hampering early detection and prevention strategies. Here, we show that PanIN are abundant in healthy individuals and present at a much higher rate than the incidence of pancreatic cancer, setting the stage for efforts to elucidate the microenvironmental and cell intrinsic factors that restrain, or, conversely, promote, malignant progression.

Aquaporins: A new target for traditional Chinese medicine in the treatment of digestive system diseases

Aquaporins (AQPs) are a family of transmembrane proteins expressed in various organ systems. Many studies have shown that the abnormal expression of AQPs is associated with gastrointestinal, skin, liver, kidneys, edema, cancer, and other diseases. The majority of AQPs are expressed in the digestive system and have important implications for the physiopathology of the gastrointestinal tract as well as other tissues and organs. AQP regulators can prevent and treat most gastrointestinal-related diseases, such as colorectal cancer, gastric ulcer, and gastric cancer. Although recent studies have proposed clinically relevant AQP-targeted therapies, such as the development of AQP inhibitors, clinical trials are still lacking and there are many difficulties. Traditional Chinese medicine (TCM) has been used in China for thousands of years to prevent, treat and diagnose diseases, and is under the guidance of Chinese medicine (CM) theory. Herein, we review the latest research on the regulation of AQPs by TCMs and their active components, including Rhei Radix et Rhizoma, Atractylodis macrocephalae Rhizoma, Salviae miltiorrhizae Radix et Rhizoma, Poria, Astragali radix, and another 26 TCMs, as well as active components, which include the active components include anthraquinones, saponins, polysaccharides, and flavonoid glycosides. Through our review and discussion of numerous studies, we attempt to explore the regulatory effects of TCMs and their active components on AQP expression in the corresponding parts of the body in terms of the Triple Energizer concept in Chinese medicine defined as "upper energizer, middle energizer, and lower energizer,"so as to offer unique opportunities for the development of AQP-related therapeutic drugs for digestive system diseases.

Comprehensive exploration of the expression and prognostic value of AQPs in clear cell renal cell carcinoma

Aquaporins (AQPs) are a family of membrane water channels that facilitate the passive transport of water across the plasma membrane of cells in response to osmotic gradients created by the active transport of solutes. Water-selective AQPs are involved in tumor angiogenesis, invasion, metastasis and growth. However, the polytype expression patterns and prognostic values of eleven AQPs in clear cell Renal Cell Cancer (ccRCC) have yet to be filled. We preliminarily investigated the transcriptional expression, survival data and immune infiltration of AQPs in patients with renal cell cancer via the Oncomine database, Kaplan-Meier Plotter, UALCAN cancer database, and cBioPortal databases. The ethical approval was waived by the local ethics committee of Peking University People's Hospital for the natural feature of mine into databases. The mRNA expression of AQP1/2/3/4/5/6/7/11 was significantly decreased in ccRCC patients. Meanwhile, MIP and AQP1/2/4/6/7/8/9/11 are notably related to the clinical stage or pathological grade of ccRCC. Lower levels of AQP1/3/4/5/7/10 expression were related to worse overall survival (OS) in patients diagnosed with ccRCC. The AQP mutation rate was 25% in ccRCC patients, but genetic alterations in AQPs were unlikely to be associated with OS and disease free survival in ccRCC patients. In addition, the expression of AQP1, AQP3, AQP4 and AQP10 was positively correlated with immune cells, and the expression of AQP6, AQP7 and AQP11 was negatively correlated with immune cells. AQP9 had a strong and significantly positive correlation with multiple immune cells. Abnormal expression of AQPs in ccRCC indicated the prognosis and immunomodulatory state of ccRCC. Further study needs to be performed to explore AQPs as new biomarkers for ccRCC.

Mechanisms underlying Nrf2 nuclear translocation by non-lethal levels of hydrogen peroxide: p38 MAPK-dependent neutral sphingomyelinase2 membrane trafficking and ceramide/PKCζ/CK2 signaling

Hydrogen peroxide is an aerobic metabolite playing a central role in redox signaling and oxidative stress. H₂O₂ could activate redox sensitive transcription factors, such as Nrf2, AP-1 and NF-κB by different manners. In some cells, treatment with non-lethal levels of H₂O₂ induces rapid activation of Nrf2, which upregulates expression of a set of genes involved in glutathione (GSH) synthesis and defenses against oxidative damage. It depends on two steps, the rapid translational activation of Nrf2 and facilitation of Nrf2 nuclear translocation. We review the molecular mechanisms by which H₂O₂ induces nuclear translocation of Nrf2 in cultured cells by highlighting the role of neutral sphingomyelinase 2 (nSMase2), a GSH sensor. H₂O₂ enters cells through aquaporin channels in the plasma membrane and is rapidly reduced to H₂O by GSH peroxidases to consume cellular GSH, resulting in nSMase2 activation to generate ceramide. H₂O₂ also activates p38 MAP kinase, which enhances transfer of nSMase2 from perinuclear regions to plasma membrane lipid rafts to accelerate ceramide generation. Low levels of ceramide activate PKCζ, which then activates casein kinase 2 (CK2). These protein kinases are able to phosphorylate Nrf2 to stabilize and activate it. Notably, Nrf2 also binds to caveolin-1 (Cav1), which protects Nrf2 from Keap1-mediated degradation and limits Nrf2 nuclear translocation. We propose that Cav1serves as a signaling hub for the control of H₂O₂-mediated phosphorylation of Nrf2 by kinases, which results in release of Nrf2 from Cav1 to facilitate nuclear translocation. In summary, H₂O₂ induces GSH depletion which is recovered by Nrf2 activation dependent on p38/nSMase2/ceramide signaling.

The Pancreas and Known Factors of Acute Pancreatitis

Pancreatitis is regarded by clinicians as one of the most complicated and clinically challenging of all disorders affecting the abdomen. It is classified on the basis of clinical, morphological, and histological criteria. Causes of acute pancreatitis can easily be identified in 75–85% of patients. The main causes of acute, recurrent acute, and chronic pancreatitis are gallstone migration and alcohol abuse. Other causes are uncommon, controversial, or unexplained. For instance, cofactors of all forms of pancreatitis are pancreas divisum and hypertriglyceridemia. Another factor that should be considered is a complication of endoscopic retrograde cholangiopancreatography: post-endoscopic retrograde cholangiopancreatography acute pancreatitis. The aim of this study is to present the known risk factors for acute pancreatitis, beginning with an account of the morphology, physiology, and development of the pancreas.

Mesenchymal stem cells- derived exosomes inhibit the expression of Aquaporin-5 and EGFR in HCT-116 human colorectal carcinoma cell line

Background

Aquaporins are channel proteins, form pores in the membrane of biological cells to facilitate the transcellular and transepithelial water movement. The role of Aquaporins in carcinogenesis has become an area of interest. In this study, we aimed to investigate the effects of adipose-derived mesenchymal stem cells secreted exosomes on the expression of aquaporin 5 and EGFR genes in the HCT-116 tumor cell line.

Methods and results

Surface antigenic profile of Ad-MSCs was evaluated using specific markers. Exosomes were purified from the Ad-MSc supernatant while the quality and the shape of isolated exosomes were assessed by western blot and transmission electron microscopy (TEM) respectively. HCT-116 cells were co-cultured with MSC-conditioned medium (MSC-CM) and/or with 100 μg/ml of MSC-derived exosomes for 48 h and. Real-time PCR was carried out to determine the expression of aquaporin5 and EGFR in HCT-116. Relative expression levels were calculated using the 2^-ΔΔct method.

Our result showed that AQP5 and EGFR mRNA levels were significantly reduced in CM and/or exosomes treated HCT116 compare to the control group (P-value < 0.05).

Conclusion

The current study showed that MSC derived exosomes could inhibit expression of two important molecules involved in tumor progression. Hence it seems MSCs-derived exosomes may hold a hopeful future as drug delivery vehicles which need the furtherer investigation.

Abnormal expression and the significant prognostic value of aquaporins in clear cell renal cell carcinoma

Aquaporins (AQPs) are a kind of transmembrane proteins that exist in various organs of the human body. AQPs play an important role in regulating water transport, lipid metabolism and glycolysis of cells. Clear cell renal cell carcinoma (ccRCC) is a common malignant tumor of the kidney, and the prognosis is worse than other types of renal cell cancer (RCC). The impact of AQPs on the prognosis of ccRCC and the potential relationship between AQPs and the occurrence and development of ccRCC are demanded to be investigated. In this study, we first explored the expression pattern of AQPs by using Oncomine, UALCAN, and HPA databases. Secondly, we constructed protein-protein interaction (PPI) network and performed function enrichment analysis through STRING, GeneMANIA, and Metascape. Then a comprehensive analysis of the genetic mutant frequency of AQPs in ccRCC was carried out using the cBioPortal database. In addition, we also analyzed the main enriched biological functions of AQPs and the correlation with seven main immune cells. Finally, we confirmed the prognostic value of AQPs throughGEPIA and Cox regression analysis. We found that the mRNA expression levels of AQP0/8/9/10 were up-regulated in patients with ccRCC, while those of AQP1/2/3/4/5/6/7/11 showed the opposite. Among them, the expression differences of AQP1/2/3/4/5/6/7/8/9/11 were statistically significant. The differences in protein expression levels of AQP1/2/3/4/5/6 in ccRCC and normal renal tissues were consistent with the change trends of mRNA. The biological functions of AQPs were mainly concentrated in water transport, homeostasis maintenance, glycerol transport, and intracellular movement of sugar transporters. The high mRNA expression levels of AQP0/8/9 were significantly correlated with worse overall survival (OS), while those of AQP1/4/7 were correlated with better OS. AQP0/1/4/9 were prognostic-related factors, and AQP1/9 were independent prognostic factors. In general, this research has investigated the values of AQPs in ccRCC, which could become new survival markers for ccRCC targeted therapy.

Aquaporin-3 and Aquaporin-5 Facilitate Migration and Cell-Cell Adhesion in Pancreatic Cancer by Modulating Cell Biomechanical Properties

BACKGROUND

Aquaporins are membrane channels responsible for the bidirectional transfer of water and small non-charged solutes across cell membranes. AQP3 and AQP5 are overexpressed in pancreatic ductal adenocarcinoma, playing key roles in cell migration, proliferation, and invasion. Here, we evaluated AQP3 and AQP5 involvement in cell biomechanical properties, cell-cell adhesion, and cell migration, following a loss-of-function strategy on BxPC-3 cells.

RESULTS

Silencing of AQP3 and AQP5 was functionally validated by reduced membrane permeability and had implications on cell migration, slowing wound recovery. Moreover, silenced AQP5 and AQP3/5 cells showed higher membrane fluidity. Biomechanical and morphological changes were assessed by atomic force microscopy (AFM), revealing AQP5 and AQP3/5 silenced cells with a lower stiffness than their control. Through cell-cell adhesion measurements, the work (energy) necessary to detach two cells was found to be lower for AQP-silenced cells than control, showing that these AQPs have implications on cell-cell adhesion.

CONCLUSION

These findings highlight AQP3 and AQP5 involvement in the biophysical properties of cell membranes, whole cell biomechanical properties, and cell-cell adhesion, thus having potential implication in the settings of tumor development.

The Characterization of Structure and Prediction for Aquaporin in Tumour Progression by Machine Learning

Recurrence and new cases of cancer constitute a challenging human health problem. Aquaporins (AQPs) can be expressed in many types of tumours, including the brain, breast, pancreas, colon, skin, ovaries, and lungs, and the histological grade of cancer is positively correlated with AQP expression. Therefore, the identification of aquaporins is an area to explore. Computational tools play an important role in aquaporin identification. In this research, we propose reliable, accurate and automated sequence predictor iAQPs-RF to identify AQPs. In this study, the feature extraction method was 188D (global protein sequence descriptor, GPSD). Six common classifiers, including random forest (RF), NaiveBayes (NB), support vector machine (SVM), XGBoost, logistic regression (LR) and decision tree (DT), were used for AQP classification. The classification results show that the random forest (RF) algorithm is the most suitable machine learning algorithm, and the accuracy was 97.689%. Analysis of Variance (ANOVA) was used to analyse these characteristics. Feature rank based on the ANOVA method and IFS strategy was applied to search for the optimal features. The classification results suggest that the 26th feature (neutral/hydrophobic) and 21st feature (hydrophobic) are the two most powerful and informative features that distinguish AQPs from non-AQPs. Previous studies reported that plasma membrane proteins have hydrophobic characteristics. Aquaporin subcellular localization prediction showed that all aquaporins were plasma membrane proteins with highly conserved transmembrane structures. In addition, the 3D structure of aquaporins was consistent with the localization results. Therefore, these studies confirmed that aquaporins possess hydrophobic properties. Although aquaporins are highly conserved transmembrane structures, the phylogenetic tree shows the diversity of aquaporins during evolution. The PCA showed that positive and negative samples were well separated by 54D features, indicating that the 54D feature can effectively classify aquaporins. The online prediction server is accessible at http://lab.malab.cn/∼acy/iAQP.

Curcumin ameliorates HO-induced injury through SIRT1-PERK-CHOP pathway in pancreatic beta cells

Oxidative stress and endoplasmic reticulum (ER) stress play crucial roles in pancreatic β cell destruction, leading to the development and progression of type 1 diabetes mellitus (T1DM). Curcumin, extracted from plant turmeric, possesses multiple bioactivities such as antioxidant, anti-inflammatory and anti-apoptosis properties and . However, it remains unknown whether curcumin improves ER stress to prevent β cells from apoptosis. In this study, we aim to investigate the role and mechanism of curcumin in ameliorating HO-induced injury in MIN6 (a mouse insulinoma cell line) cells. Cell viability is examined by CCK8 assay. Hoechst 33258 staining, TUNEL and flow cytometric assay are performed to detect cell apoptosis. The relative amounts of reactive oxygen species (ROS) are measured by DCFH-DA. WST-8 is used to determine the total superoxide dismutase (SOD) activity. Protein expressions are determined by western blot analysis and immunofluorescence staining. Pretreatment with curcumin prevents MIN6 cells from HO-induced cell apoptosis. Curcumin decreases ROS generation and inhibits protein kinase like ER kinase (PERK)-C/EBP homologous protein (CHOP) signaling axis, one of the critical branches of ER stress pathway. Moreover, incubation with curcumin activates silent information regulator 1 (SIRT1) expression and subsequently decreases the expression of CHOP. Additionally, EX527, a specific inhibitor of SIRT1, blocks the protective effect of curcumin on MIN6 cells exposed to HO. In sum, curcumin inhibits the PERK-CHOP pathway of ER stress mediated by SIRT1 and thus ameliorates HO-induced MIN6 cell apoptosis, suggesting that curcumin and SIRT1 may provide a potential therapeutic approach for T1DM.

Aquaporins implicated in the cell proliferation and the signaling pathways of cell stemness

Aquaporins (AQPs) are water channel proteins facilitating passive transport of water and other small molecules across biomembranes. Regulation of osmotic homeostasis via AQPs is accompanied by dynamic participation of various cellular signaling pathways. Recently emerging evidence reveals that functional roles of AQPs are further extended from the osmotic regulation via water permeation into the cell proliferation and differentiation. In particular, anomalous expression of AQPs has been demonstrated in various types of cancer cells and cancer stem-like cells and it has been proposed as markers for proliferation and progression of cancer cells. Thus, a more comprehensive view on AQPs could bring a great interest in the cell stemness accompanied by the expression of AQPs. AQPs are broadly expressed across tissues and cells in a cell type- and lineage-specific manner during development via spatiotemporal transcriptional regulation. Moreover, AQPs are expressed in various adult stem cells and cells associated with a stem cell niche as well as cancer stem-like cells. However, the expression and regulatory mechanisms of AQP expression in stem cells have not been well understood. This review highlighted the AQPs expression in stem cell niches/stem cells and the involvement of AQPs in the cell proliferation and signaling pathways associated with cell stemness.

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-1β, 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-1β 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.

Exocrine Pancreas Dysfunction in Type 1 Diabetes

OBJECTIVE

Type 1 diabetes (T1D) is characterized by autoimmune β-cell destruction, but exocrine pancreas abnormalities may also play a role in the disease pathophysiology. Herein, we review the current evidence of exocrine damage in T1D and discuss its underlying pathophysiology, clinical evaluation, and treatment.

METHOD

Extensive literature search was performed for "type 1 diabetes" and "exocrine dysfunction" on PubMed and Google Scholar databases.

RESULTS

T1D pancreata are significantly smaller than controls, both in weight and volume. T cells, dendritic cells, neutrophils, and products of complement activation are seen in T1D exocrine tissues. Exocrine pancreas fibrosis, arteriosclerosis, fatty infiltration, and acinar atrophy are also observed on histology. Pancreatic exocrine insufficiency (PEI) can be assessed through direct exocrine testing, fecal elastase concentration, and measurement of serum exocrine enzymes. The prevalence of PEI in T1D varies by modality and study but is consistently greater than controls. The clinical relevance of PEI in T1D is debatable, as many patients with laboratory evidence of PEI are asymptomatic. However, in PEI-symptomatic patients reported benefits of pancreatic enzyme replacement therapy (PERT) include relief of gastrointestinal symptoms, improved quality of life, better glycemic control, and optimal nutrition.

CONCLUSION

Exocrine pancreas abnormalities often occur in T1D. Whether exocrine dysfunction occurs simultaneously with β-cell destruction, as a result of β-cell loss, or as a combination of both remains to be definitively answered. In T1D with gastrointestinal complaints, PEI should be evaluated, usually via fecal elastase measurements. PERT is recommended for T1D patients with symptoms and laboratory evidence of PEI.

ABBREVIATIONS

AAb+ = autoantibody positive; AAb- = autoantibody negative; FEC = fecal elastase concentration; PEI = pancreatic exocrine insufficiency; PERT = pancreatic enzyme replacement therapy; PP = pancreatic polypep-tide; T1D = type 1 diabetes.

Ion Channel Signature in Healthy Pancreas and Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is the fourth most common cause of cancer-related deaths in United States and Europe. It is predicted that PDAC will become the second leading cause of cancer-related deaths during the next decades. The development of PDAC is not well understood, however, studies have shown that dysregulated exocrine pancreatic fluid secretion can contribute to pathologies of exocrine pancreas, including PDAC. The major roles of healthy exocrine pancreatic tissue are secretion of enzymes and bicarbonate rich fluid, where ion channels participate to fine-tune these biological processes. It is well known that ion channels located in the plasma membrane regulate multiple cellular functions and are involved in the communication between extracellular events and intracellular signaling pathways and can function as signal transducers themselves. Hereby, they contribute to maintain resting membrane potential, electrical signaling in excitable cells, and ion homeostasis. Despite their contribution to basic cellular processes, ion channels are also involved in the malignant transformation from a normal to a malignant phenotype. Aberrant expression and activity of ion channels have an impact on essentially all hallmarks of cancer defined as; uncontrolled proliferation, evasion of apoptosis, sustained angiogenesis and promotion of invasion and migration. Research indicates that certain ion channels are involved in the aberrant tumor growth and metastatic processes of PDAC. The purpose of this review is to summarize the important expression, localization, and function of ion channels in normal exocrine pancreatic tissue and how they are involved in PDAC progression and development. As ion channels are suggested to be potential targets of treatment they are furthermore suggested to be biomarkers of different cancers. Therefore, we describe the importance of ion channels in PDAC as markers of diagnosis and clinical factors.

Important players in carcinogenesis as potential targets in cancer therapy: an update

The development of cancer is a problem that has accompanied mankind for years. The growing number of cases, emerging drug resistance, and the need to reduce the serious side effects of pharmacotherapy are forcing scientists to better understand the complex mechanisms responsible for the initiation, promotion, and progression of the disease. This paper discusses the modulation of the particular stages of carcinogenesis by selected physiological factors, including: acetylcholine (ACh), peroxisome proliferator-activated receptors (PPAR), fatty acid-binding proteins (FABPs), Bruton's tyrosine kinase (Btk), aquaporins (AQPs), insulin-like growth factor-2 (IGF-2), and exosomes. Understanding their role may contribute to the development of more effective and safer therapies based on new binding sites.

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 β-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 β-cell function.

Pancreatic Cancer detection via Galectin-1-targeted Thermoacoustic Imaging: validation in an in vivo heterozygosity model

Purpose: To investigate the feasibility of microwave-induced thermoacoustic imaging (MTAI) in detecting small pancreatic tumors (< 10 mm in diameter) and to complement the limitation of current clinical imaging methods.

Methods: A home-made MTAI system composed of a portable antenna and pulsed microwave generator was developed. The thermoacoustic nanoparticles were composed of the galectin-1 antibody for targeting pancreatic tumors and Fe₃O₄ nanoparticles as microwave absorbers (anti-Gal1-Fe₃O₄ nanoparticles). The microwave absorption properties of the nanoparticles were measured with a vector network analyzer and the resolving power of MTAI was investigated by imaging excised pancreatic tumors of different sizes (diameters of 1.0 mm, 3.1 mm, 5.0 mm, 7.2 mm). To simulate actual imaging scenarios, an in vivo heterozygosity model was constructed by covering the pancreatic tumors (~ 3 mm in diameter) in BALB/c nude mice with biologic tissue (~ 5 cm in depth). MTAI images of the heterozygosity model were acquired with/without the injection of the anti-Gal1-Fe₃O₄ nanoparticles and the thermoacoustic contrast from pancreatic tumors was evaluated with Student's paired t test. The data were analyzed with analysis of variance and nonparametric statistics.

Results: Following intravenous infusion, anti-Gal1-Fe₃O₄ nanoparticles efficiently accumulated in the tumor. The MTAI contrast enhancement in pancreatic tumors with anti-Gal1-Fe₃O₄ nanoparticles was verified in vitro and in vivo. The pancreatic tumors were visible in nude mice examined with MTAI with a mean contrast enhancement ratio of 2.3 ± 0.15 (standard error of the mean) (P =. 001) at 6 h post-injection of the nanoparticles. MTAI identified tiny pancreatic tumors in deep tissues with high fidelity.

Conclusion: MTAI offers deep imaging depth and high contrast when used with anti-Gal1-Fe₃O₄ nanoparticles. It can identify pancreatic tumors smaller than 5 mm, which is beyond the identification limit size (~10 mm) of other nondestructive clinical imaging methods. Thus, MTAI has great potential as an alternative imaging modality for early pancreatic cancer detection.