RESUMO
Zinc plays a crucial role both in the immune system and endocrine processes. Zinc restriction in the diet has been shown to lead to degeneration of the endocrine pancreas, resulting in hormonal imbalance within the ß-cells. Proteostasismay vary depending on the stage of a pathophysiological process, which underscores the need for tools aimed at directly analyzing biological status. Among proteomics methods, MALDI-ToF-MS can serve as a rapid peptidomics tool for analyzing extracts or by histological imaging. Here we report the optimization of MALDI imaging mass spectrometry analysis of histological thin sections from mouse pancreas. This optimization enables the identification of the major islet peptide hormones as well as the major accumulated precursors and/or proteolytic products of peptide hormones. Cross-validation of the identified peptide hormones was performed by LC-ESI-MS from pancreatic islet extracts. Mice subjected to a zinc-restricted diet exhibited a relatively lower amount of peptide intermediates compared to the control group. These findings provide evidence for a complex modulation of proteostasis by micronutrients imbalance, a phenomenon directly accessed by MALDI-MSI.
Assuntos
Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Zinco , Animais , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Camundongos , Zinco/análise , Zinco/metabolismo , Hormônios Pancreáticos/metabolismo , Ilhotas Pancreáticas/metabolismo , Camundongos Endogâmicos C57BL , Pâncreas/metabolismo , MasculinoRESUMO
BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is a deadly disease due to the lack of early detection. Because chronic pancreatitis (CP) patients are a high-risk group for pancreatic cancer, this study aimed to assess the differential miRNA profile in pancreatic tissue of patients with CP and pancreatic cancer. METHODS: MiRNAs were isolated from formalin-fixed paraffin-embedded pancreatic tissue of 22 PDAC patients, 18 CP patients, and 10 normal pancreatic tissues from autopsy (C) cases and processed for next-generation sequencing. Known and novel miRNAs were identified and analyzed for differential miRNA expression, target prediction, and pathway enrichment between groups. RESULTS: Among the miRNAs identified, 166 known and 17 novel miRNAs were found exclusively in PDAC tissues, while 106 known and 10 novel miRNAs were found specifically in CP tissues. The pathways targeted by PDAC-specific miRNAs and differentially expressed miRNAs between PDAC versus CP tissues and PDAC versus control tissues were the proteoglycans pathway, Hippo signaling pathway, adherens junction, and transforming growth factor-ß signaling pathway. CONCLUSIONS: This study resulted in a set of exclusive and differentially expressed miRNAs in PDAC and CP can be assessed for their diagnostic value. In addition, studying the role of miRNA-target gene interactions in carcinogenesis may open new therapeutic avenues.
Assuntos
Carcinoma Ductal Pancreático , MicroRNAs , Neoplasias Pancreáticas , Pancreatite Crônica , Humanos , MicroRNAs/genética , MicroRNAs/metabolismo , Neoplasias Pancreáticas/diagnóstico , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/metabolismo , Carcinoma Ductal Pancreático/diagnóstico , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/metabolismo , Pâncreas/patologia , Pancreatite Crônica/diagnóstico , Pancreatite Crônica/genética , Pancreatite Crônica/complicações , Hormônios Pancreáticos/metabolismo , Perfilação da Expressão GênicaRESUMO
CONTEXT: Distinguishing different types of diabetes is important in directing optimized treatment strategies and correlated epidemiological studies. OBJECTIVE: Through detailed analysis of hormone responses to mixed meal tolerance test (MMTT), we aimed to find representing characteristics of post-acute pancreatitis diabetes mellitus (PPDM-A) and post-chronic pancreatitis diabetes mellitus (PPDM-C). METHODS: Participants with PPDM-A, PPDM-C, type 1 diabetes, type 2 diabetes, and normal controls (NCs) underwent MMTT. Fasting and postprandial responses of serum glucose, C-peptide, insulin, glucagon, pancreatic polypeptide (PP), ghrelin, gastric inhibitory peptide (GIP), glucagon like peptide-1 (GLP-1), and peptide YY (PYY) were detected and compared among different groups. Focused analysis on calculated insulin sensitivity and secretion indices were performed to determine major causes of hyperglycemia in different conditions. RESULTS: Participants with PPDM-A were characterized by increased C-peptide, insulin, glucagon, and PP, but decreased ghrelin, GIP, and PYY compared with NCs. Patients with PPDM-C showed secretion insufficiency of C-peptide, insulin, ghrelin, and PYY, and higher postprandial responses of glucagon and PP than NCs. In particular, both fasting and postprandial levels of ghrelin in PPDM-C were significantly lower than other diabetes groups. PYY responses in patients with PPDM-A and PPDM-C were markedly reduced. Additionally, the insulin sensitivity of PPDM-A was decreased, and the insulin secretion for PPDM-C was decreased. CONCLUSION: Along with the continuum from acute to chronic pancreatitis, the pathological mechanism of PPDM changes from insulin resistance to insulin deficiency. Insufficient PYY secretion is a promising diagnostic marker for distinguishing PPDM from type 1 and type 2 diabetes. Absent ghrelin secretion to MMTT may help identify PPDM-C.
Assuntos
Grelina , Pancreatite , Humanos , Masculino , Feminino , Pessoa de Meia-Idade , Adulto , Grelina/sangue , Diagnóstico Diferencial , Pancreatite/diagnóstico , Pancreatite/sangue , Pancreatite/etiologia , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/diagnóstico , Diabetes Mellitus Tipo 2/metabolismo , Hormônios Gastrointestinais/sangue , Insulina/sangue , Peptídeo YY/sangue , Peptídeo C/sangue , Glucagon/sangue , Glicemia/análise , Glicemia/metabolismo , Período Pós-Prandial , Polipeptídeo Inibidor Gástrico/sangue , Peptídeo 1 Semelhante ao Glucagon/sangue , Diabetes Mellitus Tipo 1/sangue , Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 1/diagnóstico , Diabetes Mellitus Tipo 1/metabolismo , Estudos de Casos e Controles , Diabetes Mellitus/diagnóstico , Diabetes Mellitus/sangue , Diabetes Mellitus/metabolismo , Hormônios Pancreáticos/sangue , Hormônios Pancreáticos/metabolismo , Resistência à InsulinaRESUMO
Recent studies have implicated pre-beta and beta lipoproteins (VLDL and LDL) in the etiopathogenesis of complications of diabetes mellitus (DM). In contrast, alpha lipoprotein (HDL) is protective of the beta cells of the pancreas. This study examined the distribution of HDL in the islets of Langerhans of murine models of type 1 diabetic rats (streptozotocin (STZ)-induced DM in Wistar rats) and type 2 models of DM rats (Goto-Kakizaki (GK), non-diabetic Zucker lean (ZL), and Zucker diabetic and fatty (ZDF)). The extent by which HDL co-localizes with insulin or glucagon in the islets of the pancreas was also investigated. Pancreatic tissues of Wistar non-diabetic, diabetic Wistar, GK, ZL, and ZDF rats were processed for immunohistochemistry. Pancreatic samples of GK rats fed with either a low-fat or a high-fat diet were prepared for transmission immune-electron microscopy (TIEM) to establish the cytoplasmic localization of HDL in islet cells. HDL was detected in the core and periphery of pancreatic islets of Wistar non-diabetic and diabetic, GK, ZL, and ZDF rats. The average total of islet cells immune positive for HDL was markedly (<0.05) reduced in GK and ZDF rats in comparison to Wistar controls. The number of islet cells containing HDL was also remarkably (p < 0.05) reduced in Wistar diabetic rats and GK models fed on high-fat food. The co-localization study using immunofluorescence and TIEM techniques showed that HDL is detected alongside insulin within the secretory granules of ß-cells. HDL did not co-localize with glucagon. This observation implies that HDL may contribute to the metabolism of insulin.
Assuntos
Diabetes Mellitus Experimental , Diabetes Mellitus Tipo 2 , Ilhotas Pancreáticas , Ratos , Camundongos , Animais , Insulina/metabolismo , Glucagon/metabolismo , Diabetes Mellitus Experimental/metabolismo , Roedores , Lipoproteínas HDL/metabolismo , Ratos Wistar , Ratos Zucker , Ilhotas Pancreáticas/metabolismo , Hormônios Pancreáticos/metabolismo , Diabetes Mellitus Tipo 2/metabolismoRESUMO
Previously, we found that human pancreatic preadipocytes (PPAs) and islets influence each other and that the crosstalk with the fatty liver via the hepatokine fetuin-A/palmitate induces inflammatory responses. Here, we examined whether the mRNA-expression of pancreatic extracellular matrix (ECM)-forming and -degrading components differ in PPAs from individuals with normal glucose regulation (PPAs-NGR), prediabetes (PPAs-PD), and type 2 diabetes (PPAs-T2D), and whether fetuin-A/palmitate impacts ECM-formation/degradation and associated monocyte invasion. Human pancreatic resections were analyzed (immuno)histologically. PPAs were studied for mRNA expression by real-time PCR and protein secretion by Luminex analysis. Furthermore, co-cultures with human islets and monocyte migration assays in Transwell plates were conducted. We found that in comparison with NGR-PPAs, TIMP-2 mRNA levels were lower in PPAs-PD, and TGF-ß1 mRNA levels were higher in PPAs-T2D. Fetuin-A/palmitate reduced fibronectin, decorin, TIMP-1/-2 and TGF-ß1 mRNA levels. Only fibronectin was strongly downregulated by fetuin-A/palmitate independently of the glycemic status. Co-culturing of PPAs with islets increased TIMP-1 mRNA expression in islets. Fetuin-A/palmitate increased MMP-1, usherin and dermatopontin mRNA-levels in co-cultured islets. A transmigration assay showed increased monocyte migration towards PPAs, which was enhanced by fetuin-A/palmitate. This was more pronounced in PPAs-T2D. The expression of distinct ECM components differs in PPAs-PD and PPAs-T2D compared to PPAs-NGR, suggesting that ECM alterations can occur even in mild hyperglycemia. Fetuin-A/palmitate impacts on ECM formation/degradation in PPAs and co-cultured islets. Fetuin-A/palmitate also enhances monocyte migration, a process which might impact on matrix turnover.
Assuntos
Diabetes Mellitus Tipo 2 , Estado Pré-Diabético , Humanos , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Fibronectinas/metabolismo , Inibidor Tecidual de Metaloproteinase-1/metabolismo , alfa-2-Glicoproteína-HS/metabolismo , Matriz Extracelular/metabolismo , Hormônios Pancreáticos/metabolismo , Palmitatos/farmacologia , RNA Mensageiro/metabolismo , Adipócitos/metabolismo , Glucose/farmacologia , Glucose/metabolismoRESUMO
Introduction: Common variants in the SLC30A8 gene, encoding the secretory granule zinc transporter ZnT8 (expressed largely in pancreatic islet alpha and beta cells), are associated with altered risk of type 2 diabetes. Unexpectedly, rare loss-of-function (LoF) variants in the gene, described in heterozygous individuals only, are protective against the disease, even though knockout of the homologous SLC30A8 gene in mice leads to unchanged or impaired glucose tolerance. Here, we aimed to determine how one or two copies of the mutant R138X allele in the mouse SLC30A8 gene impacts the homeostasis of zinc at a whole-body (using non-invasive 62Zn PET imaging to assess the acute dynamics of zinc handling) and tissue/cell level [using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to map the long-term distribution of zinc and manganese in the pancreas]. Methods: Following intravenous administration of [62Zn]Zn-citrate (~7 MBq, 150 µl) in wild-type (WT), heterozygous (R138X+/-), and homozygous (R138X+/+) mutant mice (14-15 weeks old, n = 4 per genotype), zinc dynamics were measured over 60 min using PET. Histological, islet hormone immunohistochemistry, and elemental analysis with LA-ICP-MS (Zn, Mn, P) were performed on sequential pancreas sections. Bulk Zn and Mn concentration in the pancreas was determined by solution ICP-MS. Results: Our findings reveal that whereas uptake into organs, assessed using PET imaging of 62Zn, is largely unaffected by the R138X variant, mice homozygous of the mutant allele show a substantial lowering (to 40% of WT) of total islet zinc, as anticipated. In contrast, mice heterozygous for this allele, thus mimicking human carriers of LoF alleles, show markedly increased endocrine and exocrine zinc content (1.6-fold increase for both compared to WT), as measured by LA-ICP-MS. Both endocrine and exocrine manganese contents were also sharply increased in R138X+/- mice, with smaller increases observed in R138X+/+ mice. Discussion: These data challenge the view that zinc depletion from the beta cell is the likely underlying driver for protection from type 2 diabetes development in carriers of LoF alleles. Instead, they suggest that heterozygous LoF may paradoxically increase pancreatic ß-cell zinc and manganese content and impact the levels of these metals in the exocrine pancreas to improve insulin secretion.
Assuntos
Proteínas de Transporte de Cátions , Diabetes Mellitus Tipo 2 , Animais , Humanos , Camundongos , Proteínas de Transporte de Cátions/genética , Proteínas de Transporte de Cátions/metabolismo , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Manganês/metabolismo , Pâncreas/diagnóstico por imagem , Pâncreas/metabolismo , Hormônios Pancreáticos/metabolismo , Tomografia por Emissão de Pósitrons , Zinco/metabolismo , Transportador 8 de Zinco/genéticaRESUMO
The pancreas is a complex organ consisting of differentiated cells and extracellular matrix (ECM) organized adequately to enable its endocrine and exocrine functions. Although much is known about the intrinsic factors that control pancreas development, very few studies have focused on the microenvironment surrounding pancreatic cells. This environment is composed of various cells and ECM components, which play a critical role in maintaining tissue organization and homeostasis. In this study, we applied mass spectrometry to identify and quantify the ECM composition of the developing pancreas at the embryonic (E) day 14.5 and postnatal (P) day 1 stages. Our proteomic analysis identified 160 ECM proteins that displayed a dynamic expression profile with a shift in collagens and proteoglycans. Furthermore, we used atomic force microscopy to measure the biomechanical properties and found that the pancreatic ECM was soft (≤400 Pa) with no significant change during pancreas maturation. Lastly, we optimized a decellularization protocol for P1 pancreatic tissues, incorporating a preliminary crosslinking step, which effectively preserved the 3D organization of the ECM. The resulting ECM scaffold proved suitable for recellularization studies. Our findings provide insights into the composition and biomechanics of the pancreatic embryonic and perinatal ECM, offering a foundation for future studies investigating the dynamic interactions between the ECM and pancreatic cells.
Assuntos
Proteômica , Engenharia Tecidual , Engenharia Tecidual/métodos , Proteômica/métodos , Matriz Extracelular/metabolismo , Pâncreas/metabolismo , Proteínas da Matriz Extracelular/metabolismo , Hormônios Pancreáticos/metabolismo , Alicerces Teciduais/químicaRESUMO
OBJECTIVES: The past studies clearly indicated that lumican was important in the context of pancreatic cancer (PC) onset and progression, but failed to clarify the underlying mechanistic basis for such activity. As such, we evaluated the functional importance of lumican in the context of pancreatic ductal adenocarcinoma (PDAC) to understand its mechanistic role in PC. METHODS: Lumican levels were evaluated in PDAC patient tissues via quantitative real-time polymerase chain reaction, Western blotting, and immunohistochemistry approaches. The role of lumican was additionally assessed via transfecting PDAC cell lines (BxPC-3, PANC-1) with lumican knockdown or overexpression constructs and treating PDAC cell lines with exogenous recombinant human lumican. RESULTS: Lumican expression levels were significantly higher in pancreatic tumor tissues relative to healthy paracancerous tissues. Lumican knockdown in BxPC-3 and PANC-1 enhanced their proliferation and migration, but reduced cellular apoptosis. Alternatively, lumican overexpression and exogenous lumican exposure failed to alter the proliferative activity of these cells. Further, lumican knockdown in BxPC-3 and PANC-1 cells results in marked P53 and P21 dysregulation. CONCLUSIONS: Lumican may suppress PDAC tumor growth by regulating P53 and P21, and the function of lumican sugar chains in the context of PC is worth studying in future studies.
Assuntos
Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Humanos , Lumicana/genética , Lumicana/metabolismo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Neoplasias Pancreáticas/patologia , Pâncreas/patologia , Carcinoma Ductal Pancreático/patologia , Hormônios Pancreáticos/metabolismo , Proliferação de Células/genética , Linhagem Celular Tumoral , Movimento Celular , Regulação Neoplásica da Expressão Gênica , Neoplasias PancreáticasRESUMO
OBJECTIVE: The pathogenesis of acute pancreatitis mainly involves NLRP3 inflammasome-mediated pancreatic cell injury, although regulators of this inflammasome machinery are still not fully identified. Membrane-associated RING-CH 9 (MARCH9) is a member of MARCH-type finger proteins, which regulates innate immunity through catalyzing polyubiquitination of critical immune factors. The aim of present research is to examine the function of MARCH9 in acute pancreatitis. METHODS: Cerulein-induced acute pancreatitis was established on pancreatic cell line AR42J and rat model. Reactive oxygen species (ROS) accumulation and NLRP3 inflammasome-dependent cell pyroptosis in pancreas were examined by flow cytometry. RESULTS: MARCH9 was downregulated by cerulein, but overexpressing MARCH9 could inhibit NLRP3 inflammasome activation and ROS accumulation, thus suppressing pancreatic cell pyroptosis and mitigating pancreatic injury. We further uncovered that the mechanism underlying such an effect of MARCH9 is through mediating the ubiquitination of NADPH oxidase-2, whose deficiency reduces cellular ROS accumulation and inflammasome formation. CONCLUSIONS: Our results suggested that MARCH9 suppresses NLRP3 inflammasome-mediated pancreatic cell injury through mediating the ubiquitination and degradation of NADPH oxidase-2, which compromises ROS generation and NLRP3 inflammasomal activation.
Assuntos
Inflamassomos , Pancreatite , Ratos , Animais , Inflamassomos/metabolismo , Pancreatite/patologia , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Piroptose , Espécies Reativas de Oxigênio/metabolismo , Ceruletídeo/farmacologia , Doença Aguda , Pâncreas/patologia , Hormônios Pancreáticos/metabolismo , NADPH Oxidases/metabolismo , NADPH Oxidases/farmacologiaRESUMO
AIMS: Dysregulation of pancreatic fat and lipotoxic inflammation are common clinical findings in alcoholic chronic pancreatitis (ACP). In this study, we investigated a relationship between dysregulated pancreatic lipid metabolism and the development of injury in a chronic ethanol (EtOH) feeding model of hepatic alcohol dehydrogenase 1- deficient (ADH-) deer mice. METHODS: ADH- and hepatic ADH normal (ADH+) deer mice were fed a liquid diet containing 3 % EtOH for three months and received a single gavage of binge EtOH with/without fatty acid ethyl esters (FAEEs) one week before the euthanasia. Plasma and pancreatic tissue were analyzed for lipids including FAEEs, inflammatory markers and adipokines using GC-MS, bioassays/kits, and immunostaining, respectively. Pancreatic morphology and proteins involved in lipogenesis were determined by the H & E staining, electron microscopy and Western blot analysis. KEY FINDINGS: Chronic EtOH feeding in ADH- vs. ADH+ deer mice resulted in a significant increase in the levels of pancreatic lipids including FAEEs, adipokines (leptin and resistin), fat infiltration with inflammatory cells and lipid droplet deposition along with the proteins involved in lipogenesis. The changes exacerbated by an administration of binge EtOH with/without FAEEs in the pancreas of ADH- vs. ADH+ deer mice fed chronic EtOH suggest a metabolic basis for ACP. SIGNIFICANCE: These findings suggest that the liver-pancreatic axis plays a crucial role in etiopathogenesis of ACP, as the increased body burden of EtOH due to hepatic ADH deficiency exacerbates pancreatic injury.
Assuntos
Álcool Desidrogenase , Etanol , Animais , Etanol/toxicidade , Etanol/metabolismo , Álcool Desidrogenase/genética , Álcool Desidrogenase/metabolismo , Peromyscus/metabolismo , Fígado/metabolismo , Pâncreas/metabolismo , Ácidos Graxos/metabolismo , Inflamação/patologia , Hormônios Pancreáticos/metabolismo , Fenótipo , Ésteres , Adipocinas/metabolismoRESUMO
To clarify the effect of monochromatic light on circadian rhythms of plasma insulin level and pancreatic clock gene expression and its mechanism, 216 newly hatched chicks were divided into three groups (intact, sham operation and pinealectomy) and were raised under white (WL), red (RL), green (GL) or blue (BL) light for 21 days. Their plasma and pancreas were sampled at six four-hour intervals. For circadian rhythm analysis, measurements of plasma melatonin, insulin, and clock gene expression (cClock, cBmal1, cBmal2, cCry1, cCry2, cPer2, and cPer3) were made. Plasma melatonin, insulin, and the pancreatic clock gene all expressed rhythmically in the presence of monochromatic light. Red light reduced the mesor and amplitude of plasma melatonin in comparison to green light. The mesor and amplitude of the pancreatic clock gene in chickens exposed to red light were dramatically reduced, which is consistent with the drop in plasma melatonin levels. Red light, on the other hand, clearly raised the level of plasma insulin via raising the expression of cVamp2, but not cInsulin. After the pineal gland was removed, the circadian expressions of plasma melatonin and pancreatic clock gene were significantly reduced, but the plasma insulin level and the pancreatic cVamp2 expression were obviously increased, resulting in the disappearance of differences in insulin level and cVamp2 expression in the monochromatic light groups. Therefore, we hypothesize that melatonin may be crucial in the effect of monochromatic light on the circadian rhythm of plasma insulin level by influencing the expression of clock gene in chicken pancreas.
Assuntos
Insulinas , Melatonina , Glândula Pineal , Animais , Melatonina/metabolismo , Galinhas/genética , Galinhas/metabolismo , Glândula Pineal/metabolismo , Ritmo Circadiano/genética , Hormônios Pancreáticos/metabolismo , Pâncreas/metabolismo , Expressão Gênica , Insulinas/genéticaRESUMO
Organic anion transporter 1 (OAT1) expressed in the kidney plays an important role in the elimination of numerous anionic drugs used in the clinic. We report here that insulin, a pancreas-secreted hormone, regulated the expression and activity of kidney-specific OAT1 both in cultured cells and in rats. We showed that treatment of OAT1-expressing cells with insulin led to an increase in OAT1 expression, transport activity, and SUMOylation. Such insulin-induced increase was blocked by afuresertib, a specific inhibitor for protein kinase B (PKB), suggesting insulin regulates OAT1 through PKB signaling pathway. Furthermore, insulin stimulated transport activity and SUMOylation of endogenously expressed OAT1 in rat kidneys. In conclusion, our data support a remote sensing and signaling model, in which OAT1 plays an essential role in intercellular and inter-organ communication and in maintaining local and whole-body homeostasis. Such complex and dedicated communication is carried out by insulin, and PKB signaling and membrane sorting.
Assuntos
Insulina , Proteína 1 Transportadora de Ânions Orgânicos , Ratos , Animais , Insulina/metabolismo , Proteína 1 Transportadora de Ânions Orgânicos/metabolismo , Tecnologia de Sensoriamento Remoto , Rim/metabolismo , Transdução de Sinais , Hormônios Pancreáticos/metabolismo , Insulina Regular Humana , Transportadores de Ânions Orgânicos Sódio-Independentes/metabolismoRESUMO
Cofactor flavin adenine dinucleotide (FAD), a compound with flavin moiety and a derivative of riboflavin (vitamin B2), is shown to bind to Sox9 (a key transcription factor in early pancreatic development) and, subsequently, induce a large increase in markers of pancreatic development, including Ngn3 and PTF1a. Pyridoxal 5'-phosphate (PLP), the active form of vitamin B6, also binds to Sox9 and results in a similar increase in pancreatic development markers. Sox9 is known to be specifically important for pancreatic progenitors. Previously, there was no known link between FAD, PLP, or other co-factors and Sox9 for function. Thus, our findings show the mechanism by which FAD and PLP interact with Sox9 and result in the altered expression of pancreatic progenitor transcription factors involved in the pancreas development.
Assuntos
Flavina-Adenina Dinucleotídeo , Pâncreas , Flavina-Adenina Dinucleotídeo/metabolismo , Pâncreas/metabolismo , Hormônios Pancreáticos/metabolismo , Riboflavina/metabolismo , Fosfato de Piridoxal/metabolismo , Fosfatos/metabolismo , Vitaminas/metabolismoRESUMO
Adrenaline inhibits insulin secretion from pancreatic beta cells to allow an organism to cover immediate energy needs by unlocking internal nutrient reserves. The stimulation of α2-adrenergic receptors on the plasma membrane of beta cells reduces their excitability and insulin secretion mostly through diminished cAMP production and downstream desensitization of late step(s) of exocytotic machinery to cytosolic Ca2+ concentration ([Ca2+]c). In most studies unphysiologically high adrenaline concentrations have been used to evaluate the role of adrenergic stimulation in pancreatic endocrine cells. Here we report the effect of physiological adrenaline levels on [Ca2+]c dynamics in beta cell collectives in mice pancreatic tissue slice preparation. We used confocal microscopy with a high spatial and temporal resolution to evaluate glucose-stimulated [Ca2+]c events and their sensitivity to adrenaline. We investigated glucose concentrations from 8-20 mM to assess the concentration of adrenaline that completely abolishes [Ca2+]c events. We show that 8 mM glucose stimulation of beta cell collectives is readily inhibited by the concentration of adrenaline available under physiological conditions, and that sequent stimulation with 12 mM glucose or forskolin in high nM range overrides this inhibition. Accordingly, 12 mM glucose stimulation required at least an order of magnitude higher adrenaline concentration above the physiological level to inhibit the activity. To conclude, higher glucose concentrations stimulate beta cell activity in a non-linear manner and beyond levels that could be inhibited with physiologically available plasma adrenaline concentration.
Assuntos
Células Secretoras de Insulina , Ilhotas Pancreáticas , Camundongos , Animais , Células Secretoras de Insulina/metabolismo , Epinefrina , Ilhotas Pancreáticas/metabolismo , Insulina/metabolismo , Glucose/metabolismo , Hormônios Pancreáticos/metabolismoRESUMO
Glucose metabolism is primarily controlled by pancreatic hormones, with the coordinated assistance of the hormones from gastrointestine and adipose tissue. Studies have unfolded a sophisticated hormonal gastrointestinal-pancreatic-adipose interaction network, which essentially maintains glucose homeostasis in response to the changes in substrates and nutrients. Free fatty acids (FFAs) are the important substrates that are involved in glucose metabolism. FFAs are able to activate the G-protein coupled membrane receptors including GPR40, GPR120, GPR41 and GPR43, which are specifically expressed in pancreatic islet cells, enteroendocrine cells as well as adipocytes. The activation of FFA receptors regulates the secretion of hormones from pancreas, gastrointestine and adipose tissue to influence glucose metabolism. This review presents the effects of the FFA receptors on glucose metabolism via the hormonal gastrointestinal-pancreatic-adipose interactions and the underlying intracellular mechanisms. Furthermore, the development of therapeutic drugs targeting FFA receptors for the treatment of abnormal glucose metabolism such as type 2 diabetes mellitus is summarized.
Assuntos
Diabetes Mellitus Tipo 2 , Ácidos Graxos não Esterificados , Tecido Adiposo/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Ácidos Graxos não Esterificados/metabolismo , Glucose/metabolismo , Humanos , Pâncreas/metabolismo , Hormônios Pancreáticos/metabolismo , Receptores Acoplados a Proteínas G/metabolismoRESUMO
Oncogenic K-ras is often activated in pancreatic ductal adenocarcinoma (PDAC) due to frequent mutation (>90%), which drives multiple cellular processes, including alterations in lipid metabolism associated with a malignant phenotype. However, the role and mechanism of the altered lipid metabolism in K-ras-driven cancer remains poorly understood. In this study, using human pancreatic epithelial cells harboring inducible K-rasG12D (HPNE/K-rasG12D) and pancreatic cancer cell lines, we found that the expression of phospholipase A2 group IIA (PLA2G2A) was upregulated by oncogenic K-ras. The elevated expression of PLA2G2A was also observed in pancreatic cancer tissues and was correlated with poor survival of PDAC patients. Abrogation of PLA2G2A by siRNA or by pharmacological inhibition using tanshinone I significantly increased lipid peroxidation, reduced fatty acid synthase (FASN) expression, and impaired mitochondrial function manifested by a decrease in mitochondrial transmembrane potential and a reduction in ATP production, leading to the inhibition of cancer cell proliferation. Our study suggests that high expression of PLA2G2A induced by oncogenic K-ras promotes cancer cell survival, likely by reducing lipid peroxidation through its ability to facilitate the removal of polyunsaturated fatty acids from lipid membranes by enhancing the de novo fatty acid synthesis and energy metabolism to support cancer cell proliferation. As such, PLA2G2A might function as a downstream mediator of K-ras and could be a potential therapeutic target.
Assuntos
Carcinoma Ductal Pancreático , Fosfolipases A2 do Grupo II , Neoplasias Pancreáticas , Trifosfato de Adenosina/metabolismo , Carcinoma Ductal Pancreático/patologia , Linhagem Celular Tumoral , Metabolismo Energético , Ácidos Graxos , Fosfolipases A2 do Grupo II/metabolismo , Humanos , Lipídeos , Mutação , Hormônios Pancreáticos/metabolismo , Neoplasias Pancreáticas/patologia , RNA Interferente Pequeno/metabolismo , Neoplasias PancreáticasRESUMO
Chromogranin A (CgA) is a 439 amino acid protein secreted by neuroendocrine cells. Proteolytic processing of CgA results in the production of different bioactive peptides. These peptides have been associated with inflammatory bowel disease, diabetes, and cancer. One of the chromogranin A-derived peptides is â¼52 amino acid long Pancreastatin (PST: human (h)CgA250-301, murine (m)CgA263-314). PST is a glycogenolytic peptide that inhibits glucose-induced insulin secretion from pancreatic islet ß-cells. In addition to this metabolic role, evidence is emerging that PST also has inflammatory properties. This review will discuss the immunomodulatory properties of PST and its possible mechanisms of action and regulation. Moreover, this review will discuss the potential translation to humans and how PST may be an interesting therapeutic target for treating inflammatory diseases.
Assuntos
Cromograninas , Hormônios Pancreáticos , Humanos , Animais , Camundongos , Cromogranina A/farmacologia , Hormônios Pancreáticos/metabolismo , Cromograninas/metabolismo , Peptídeos , AminoácidosRESUMO
Cancer-associated fibroblasts (CAFs) are one of the most prominent and active components in the pancreatic tumor microenvironment. Our data show that CAFs are critical for survival from pancreatic ductal adenocarcinoma (PDAC) on glutamine deprivation. Specifically, we uncovered a role for nucleosides, which are secreted by CAFs through autophagy in a nuclear fragile X mental retardation-interacting protein 1 (NUFIP1)-dependent manner, increased glucose utilization and promoted growth of PDAC. Moreover, we demonstrate that CAF-derived nucleosides induced glucose consumption under glutamine-deprived conditions and displayed a dependence on MYC. Using an orthotopic mouse model of PDAC, we found that inhibiting nucleoside secretion by targeting NUFIP1 in the stroma reduced tumor weight. This finding highlights a previously unappreciated metabolic network within pancreatic tumors in which diverse nutrients are used to promote growth in an austere tumor microenvironment.
Assuntos
Fibroblastos Associados a Câncer , Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Animais , Autofagia , Fibroblastos Associados a Câncer/metabolismo , Carcinoma Ductal Pancreático/metabolismo , Proliferação de Células , Glucose/farmacologia , Glutamina/metabolismo , Camundongos , Proteínas Nucleares/metabolismo , Nucleosídeos/metabolismo , Hormônios Pancreáticos/metabolismo , Neoplasias Pancreáticas/metabolismo , Proteínas de Ligação a RNA/metabolismo , Microambiente Tumoral , Neoplasias PancreáticasRESUMO
Cyanidin-3-O-glucoside (C3G) is a natural colorant with anti-diabetic properties, while its underlying mechanisms remain far from clear. Here, we investigated the protective role of C3G on palmitic acid (PA)-induced pancreatic beta cell dysfunction and further decipher its possible molecular mechanisms. Both primary isolated mouse islets and the INS-1E cell were used, and treated with a mixture of PA (0.5 mM) and C3G (12.5 µM, 25 µM, 50 µM) for different durations (12, 24, 48 h). We found that C3G could dose-dependently ameliorate beta cell secretory function and further alleviate cell apoptosis. Mechanistically, the primary role of the PKR-like ER kinase (PERK) endoplasmic reticulum (ER) stress pathway was detected by RNA sequencing, and the PERK-pathway-related protein expression, especially the pro-apoptotic marker C/EBP homologous protein (CHOP) expression, was significantly downregulated by C3G treatment. The critical role of CHOP in mediating the protective effect of C3G was further validated by small interfering RNA. Conclusively, C3G could ameliorate PA-induced pancreatic beta cell dysfunction targeting the CHOP-related ER stress pathway, which might be used as a nutritional intervention for the preservation of beta cell dysfunction in type 2 diabetes mellitus.
Assuntos
Diabetes Mellitus Tipo 2 , Células Secretoras de Insulina , Animais , Antocianinas , Apoptose , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/metabolismo , Estresse do Retículo Endoplasmático , Glucosídeos/farmacologia , Células Secretoras de Insulina/metabolismo , Camundongos , Ácido Palmítico/metabolismo , Hormônios Pancreáticos/metabolismo , Transdução de Sinais , Fator de Transcrição CHOP/genética , Fator de Transcrição CHOP/metabolismoRESUMO
Elevated levels of Mucin-16 (MUC16) in conjunction with a high expression of truncated O-glycans is implicated in playing crucial roles in the malignancy of pancreatic ductal adenocarcinoma (PDAC). However, the mechanisms by which such aberrant glycoforms present on MUC16 itself promote an increased disease burden in PDAC are yet to be elucidated. This study demonstrates that the CRISPR/Cas9-mediated genetic deletion of MUC16 in PDAC cells decreases tumor cell migration. We found that MUC16 enhances tumor malignancy by activating the integrin-linked kinase and focal adhesion kinase (ILK/FAK)-signaling axis. These findings are especially noteworthy in truncated O-glycan (Tn and STn antigen)-expressing PDAC cells. Activation of these oncogenic-signaling pathways resulted in part from interactions between MUC16 and integrin complexes (α4ß1), which showed a stronger association with aberrant glycoforms of MUC16. Using a monoclonal antibody to functionally hinder MUC16 significantly reduced the migratory cascades in our model. Together, these findings suggest that truncated O-glycan containing MUC16 exacerbates malignancy in PDAC by activating FAK signaling through specific interactions with α4 and ß1 integrin complexes on cancer cell membranes. Targeting these aberrant glycoforms of MUC16 can aid in the development of a novel platform to study and treat metastatic pancreatic cancer.