Response Of Acinar Cells Research Articles

In vitro effects of Ganoderic acid A on NF-κB-mediated inflammatory response in caerulein-stimulated pancreatic acinar cells

In vitro effects of Ganoderic acid A on NF-κB-mediated inflammatory response in caerulein-stimulated pancreatic acinar cells

Age-Related Decline in Pancreas Regeneration Is Associated With an Increased Proinflammatory Response to Injury

Background and AimsThe regenerative capacity of the pancreas diminishes with age. Understanding acinar cell responses to injury and the resolution of regenerative processes is crucial for tissue homeostasis. However, knowledge about the impact of aging on these processes remains limited. MethodsTo investigate the influence of aging on pancreas regeneration, we established a cohort of young (7-14 weeks) and old (18 months) C57bl/6 mice. Experimental pancreatitis was induced using caerulein, and pancreas samples were collected at various timepoints after induction, covering acute damage response, inflammation, peak proliferation, and inflammation resolution. Our analysis involved immunohistochemistry, quantitative imaging, and gene expression analyses.Our study revealed a significant decline in the regenerative capacity of the pancreas in old mice. Despite similar morphology and transcriptional profiles between the pancreas of young and old mice under homeostasis, the aged pancreas is primed to generate an exacerbated proinflammatory reaction in response to injury. Specifically, we observed notable upregulation of Junb expression in acinar cells and aberrant myofibroblast activation in aged pancreas. ConclusionsThe response of acinar cells to injury in the pancreas of aged mice is characterized by an increased susceptibility to inflammation and stromal reactions. Our findings uncover a pre-existing proinflammatory state in aged acinar cells, offering insights into potential strategies to prevent the onset of pancreatic insufficiency and the development of inflammatory conditions. These insights hold implications for preventing conditions such as chronic pancreatitis and pancreatic ductal adenocarcinoma.

Ca2+ signals in pancreatic acinar cells in response to physiological stimulation in vivo.

The exocrine pancreas secretes fluid and digestive enzymes in response to parasympathetic release of acetylcholine (ACh) via the vagus nerve and the gut hormone cholecystokinin (CCK). Both secretion of fluid and exocytosis of secretory granules containing enzymes and zymogens are dependent on an increase in the cytosolic [Ca2+ ] in acinar cells. It is thought that the specific spatiotemporal characteristics of the Ca2+ signals are fundamental for appropriate secretion and that these properties are disrupted in disease states in the pancreas. While extensive research has been performed to characterize Ca2+ signalling in acinar cells, this has exclusively been achieved in ex vivo preparations of exocrine cells, where it is difficult to mimic physiological conditions. Here we have developed a method to optically observe pancreatic acinar Ca2+ signals in vivo using a genetically expressed Ca2+ indicator and imaged with multi-photon microscopy in live animals. In vivo, acinar cells exhibited baseline activity in fasted animals, which was dependent on CCK1 receptors (CCK1Rs). Both stimulation of intrinsic nervous input and administration of systemic CCK induced oscillatory activity in a proportion of the cells, but the maximum frequencies were vastly different. Upon feeding, oscillatory activity was also observed, which was dependent on CCK1Rs. No evidence of a vago-vagal reflex mediating the effects of CCK was observed. Our in vivo method revealed the spatial and temporal profile of physiologically evoked Ca2+ signals, which will provide new insights into future studies of the mechanisms underlying exocrine physiology and that are disrupted in pathological conditions. KEY POINTS: In the exocrine pancreas, the spatiotemporal properties of Ca2+ signals are fundamentally important for the appropriate stimulation of secretion by the neurotransmitter acetylcholine and gut hormone cholecystokinin. These characteristics were previously defined in ex vivo studies. Here we report the spatiotemporal characteristics of Ca2+ signals in vivo in response to physiological stimulation in a mouse engineered to express a Ca2+ indicator in acinar cells. Specific Ca2+ 'signatures' probably important for stimulating secretion are evoked in vivo in fasted animals, by feeding, neural stimulation and cholecystokinin administration. The Ca2+ signals are probably the result of the direct action of ACh and CCK on acinar cells and not indirectly through a vago-vagal reflex.

Sphingosine 1-phosphate receptor 2 mediated early stages of pancreatic and systemic inflammatory responses via NF-kappa B activation in acute pancreatitis

In acute pancreatitis, activation of inflammatory signaling, including the nuclear factor-kappa B (NF-κB) pathway, within acinar cells is known to be an early intracellular event occurring in parallel with pathologic trypsinogen activation. Sphingosine 1-phosphate receptor 2 (S1PR2) plays a critical role in endothelial inflammation, and our previous studies reported that S1PR2 deficiency significantly reduced the inflammatory response in liver injury under cholestasis conditions. However, the role of S1PR2 in inflammatory signaling activation within acinar cells and inflammatory responses during acute pancreatitis has not been elucidated. Here we report that S1PR2 was upregulated in the whole pancreas during acute pancreatitis. Blockade of S1PR2 by pharmacologic inhibition of S1PR2 by JTE-013 or AAV-mediated knockdown of S1PR2 improved the severity of pancreatic injury, as indicated by a significant reduction in inflammation and acinar cells death in acute pancreatitis mice. Moreover, S1PR2 is the predominant S1PRs expressed in pancreatic acinar cells and mediates NF-κB activation and the early inflammatory response within acinar cells under acute pancreatitis conditions via ROCK signaling pathways, not extracellular signal-regulated kinase pathways or p38 mitogen-activated protein kinase pathways. In addition, S1PR2 mediated macrophage NF-κB activation, migration and polarization toward the M1 phenotype. Therefore, these results demonstrated that the S1PR2-mediated early inflammatory response in acinar cells promotes the progression of acute pancreatitis, successfully linking local events to the systematic inflammatory response and leading to a novel therapeutic target for acute pancreatitis aimed at halting the progression of the inflammatory response.4Upw5czRUXogyYiQEsPybuVideo

Calcium imaging in intact mouse acinar cells in acute pancreas tissue slices.

The physiology and pathophysiology of the exocrine pancreas are in close connection to changes in intra-cellular Ca2+ concentration. Most of our knowledge is based on in vitro experiments on acinar cells or acini enzymatically isolated from their surroundings, which can alter their structure, physiology, and limit our understanding. Due to these limitations, the acute pancreas tissue slice technique was introduced almost two decades ago as a complementary approach to assess the morphology and physiology of both the endocrine and exocrine pancreas in a more conserved in situ setting. In this study, we extend previous work to functional multicellular calcium imaging on acinar cells in tissue slices. The viability and morphological characteristics of acinar cells within the tissue slice were assessed using the LIVE/DEAD assay, transmission electron microscopy, and immunofluorescence imaging. The main aim of our study was to characterize the responses of acinar cells to stimulation with acetylcholine and compare them with responses to cerulein in pancreatic tissue slices, with special emphasis on inter-cellular and inter-acinar heterogeneity and coupling. To this end, calcium imaging was performed employing confocal microscopy during stimulation with a wide range of acetylcholine concentrations and selected concentrations of cerulein. We show that various calcium oscillation parameters depend monotonically on the stimulus concentration and that the activity is rather well synchronized within acini, but not between acini. The acute pancreas tissue slice represents a viable and reliable experimental approach for the evaluation of both intra- and inter-cellular signaling characteristics of acinar cell calcium dynamics. It can be utilized to assess many cells simultaneously with a high spatiotemporal resolution, thus providing an efficient and high-yield platform for future studies of normal acinar cell biology, pathophysiology, and screening pharmacological substances.

Production of Human Pancreatitis-Associated Protein (hPAP) in Komagataella phaffii (Pichia pastoris)


 
 Pancreatitis-associated protein (PAP) is a pancreatic stress protein that is not produced in a healthy pancreas but is highly synthesized in pancreatic acinar cells in response to acute and chronic pancreatitis, hypoxia, toxins, diabetes, lipopolysaccharides hypotransferrinemia and organ transplantation. Changes in the PAP levels in serum are an important biological marker in the early stage of pancreatic diseases. In this study, the recombinant human PAP protein, which has the potential to be used as a diagnostic marker and as research material in proliferation, apoptosis, cell migration, cell invasion, and immunoassay studies, was expressed efficiently under the control of the AOX1 gene promoter in the Komagataella phaffii (Pichia pastoris) (K. phaffii) X33 strain. We describe the conditions required for the efficient production of PAP protein by methanol induction and its use without purification. The produced unpurified protein was tested in sandwich ELISA and showed consistent results with the commercial product. These results are encouraging that the protein produced can be used as a biomarker standard in ELISA tests without the cost and labor of purification.
 
 
 
 

Kynurenic Acid and Its Analogue SZR-72 Ameliorate the Severity of Experimental Acute Necrotizing Pancreatitis

The pathophysiology of acute pancreatitis (AP) is not well understood, and the disease does not have specific therapy. Tryptophan metabolite L-kynurenic acid (KYNA) and its synthetic analogue SZR-72 are antagonists of the N-methyl-D-aspartate receptor (NMDAR) and have immune modulatory roles in several inflammatory diseases. Our aims were to investigate the effects of KYNA and SZR-72 on experimental AP and to reveal their possible mode of action. AP was induced by intraperitoneal (i.p.) injection of L-ornithine-HCl (LO) in SPRD rats. Animals were pretreated with 75-300 mg/kg KYNA or SZR-72. Control animals were injected with physiological saline instead of LO, KYNA and/or SZR-72. Laboratory and histological parameters, as well as pancreatic and systemic circulation were measured to evaluate AP severity. Pancreatic heat shock protein-72 and IL-1β were measured by western blot and ELISA, respectively. Pancreatic expression of NMDAR1 was investigated by RT-PCR and immunohistochemistry. Viability of isolated pancreatic acinar cells in response to LO, KYNA, SZR-72 and/or NMDA administration was assessed by propidium-iodide assay. The effects of LO and/or SZR-72 on neutrophil granulocyte function was also studied. Almost all investigated laboratory and histological parameters of AP were significantly reduced by administration of 300 mg/kg KYNA or SZR-72, whereas the 150 mg/kg or 75 mg/kg doses were less or not effective, respectively. The decreased pancreatic microcirculation was also improved in the AP groups treated with 300 mg/kg KYNA or SZR-72. Interestingly, pancreatic heat shock protein-72 expression was significantly increased by administration of SZR-72, KYNA and/or LO. mRNA and protein expression of NMDAR1 was detected in pancreatic tissue. LO treatment caused acinar cell toxicity which was reversed by 250 µM KYNA or SZR-72. Treatment of acini with NMDA (25, 250, 2000 µM) did not influence the effects of KYNA or SZR-72. Moreover, SZR-72 reduced LO-induced H2O2 production of neutrophil granulocytes. KYNA and SZR-72 have dose-dependent protective effects on LO-induced AP or acinar toxicity which seem to be independent of pancreatic NMDA receptors. Furthermore, SZR-72 treatment suppressed AP-induced activation of neutrophil granulocytes. This study suggests that administration of KYNA and its derivative could be beneficial in AP.

Priming Low-Dose Gamma Irradiation Increases Cellular Radioadaptation Response through the Induction of Hsp70 and SOD2

Exposure to low-dose radiation has been demonstrated to stimulate increased cell protection when receiving subsequent challenge dose in what is known as radioadaptation response. Hsp70 and SOD, especially SOD2, are cytoprotectors against superoxide radicals generated by radiation exposure. This study aims to measure the expressions of Hsp70 and SOD2 in parotid salivary gland acinar cells as an indicator of radioadaptation response stimulated by low-dose gamma irradiation. The study used 24 male Rattus norvegicus that are divided into four groups: normal control, positive control, with 50-mGy priming irradiation, and with 100-mGy priming irradiation. The animals were immobilized without anesthetics with special tools designed especially for this study. Irradiation was carried out using a cobalt-60 (gamma ray) teletherapy unit (Philips XK-100) directed to the dorsa of the animals’ heads . High-dose gamma irradiation (2 Gy) was administered 5 hours after priming irradiation. The expression of Hsp70 and SOD2 was measured through immunohistochemical technique on the parotid salivary gland acinar cells and observed using a light microscope with 1000× magnification. Data obtained was analyzed with one-way ANOVA test ( α = 0.05). The results showed that Hsp70 and SOD2 expressions in the priming irradiation groups were higher than those in control groups. The conclusion of this study: priming irradiation with low-dose gamma radiation before challenge irradiation with high-dose gamma radiation increases the radioadaptation response of salivary gland acinar cells through induction of Hsp70 and SOD2.

SETD4-expressing cells contribute to pancreatic development and response to cerulein induced pancreatitis injury

In the adult pancreas, the presence of progenitor or stem cells and their potential involvement in homeostasis and regeneration remains unclear. Here, we identify that SET domain-containing protein 4 (SETD4), a histone lysine methyltransferase, is expressed in a small cell population in the adult mouse pancreas. Genetic lineage tracing shows that during pancreatic development, descendants of SETD4+ cells make up over 70% of pancreatic cells and then contribute to each pancreatic lineage during pancreatic homeostasis. SETD4+ cells generate newborn acinar cells in response to cerulein-induced pancreatitis in acinar compartments. Ablation of SETD4+ cells compromises regeneration of acinar cells, in contrast to controls. Our findings provide a new cellular narrative for pancreatic development, homeostasis and response to injury via a small SETD4+ cell population. Potential applications may act to preserve pancreatic function in case of pancreatic disease and/or damage.

Differential cytotoxicity, ER/oxidative stress, dysregulated AMPKα signaling, and mitochondrial stress by ethanol and its metabolites in human pancreatic acinar cells.

Alcoholic chronic pancreatitis (ACP) is a serious inflammatory disorder of the exocrine pancreatic gland. A previous study from this laboratory showed that ethanol (EtOH) causes cytotoxicity, dysregulates AMPKα and ER/oxidative stress signaling, and induces inflammatory responses in primary human pancreatic acinar cells (hPACs). Here we examined the differential cytotoxicity of EtOH and its oxidative (acetaldehyde) and nonoxidative (fatty acid ethyl esters; FAEEs) metabolites in hPACs was examined to understand the metabolic basis and mechanism of ACP. We evaluated concentration-dependent cytotoxicity, AMPKα inactivation, ER/oxidative stress, and inflammatory responses in hPACs by incubating them for 6 h with EtOH, acetaldehyde, or FAEEs at clinically relevant concentrations reported in alcoholic subjects using conventional methods. Cellular bioenergetics (mitochondrial stress and a real-time ATP production rate) were determined using Seahorse XFp Extracellular Flux Analyzer in AR42J cells treated with acetaldehyde or FAEEs. We observed concentration-dependent increases in LDH release, inactivation of AMPKα along with upregulation of ACC1 and FAS (key lipogenic proteins), downregulation of p-LKB1 (an oxidative stress-sensitive upstream kinase regulating AMPKα) and CPT1A (involved in β-oxidation of fatty acids) in hPACs treated with EtOH, acetaldehyde, or FAEEs. Concentration-dependent increases in oxidative stress and ER stress as measured by GRP78, unspliced XBP1, p-eIF2α, and CHOP along with activation of p-JNK1/2, p-ERK1/2, and p-P38MAPK were present in cells treated with EtOH, acetaldehyde, or FAEEs, respectively. Furthermore, a significant decrease was observed in the total ATP production rate with subsequent mitochondrial stress in AR42J cells treated with acetaldehyde and FAEEs. EtOH and its metabolites, acetaldehyde and FAEEs, caused cytotoxicity, ER/oxidative and mitochondrial stress, and dysregulated AMPKα signaling, suggesting a key role of EtOH metabolism in the etiopathogenesis of ACP. Because oxidative EtOH metabolism is negligible in the exocrine pancreas, the pathogenesis of ACP could be attributable to the formation of FAEEs and related pancreatic acinar cell injury.

A multilayered post-GWAS assessment on genetic susceptibility to pancreatic cancer

BackgroundPancreatic cancer (PC) is a complex disease in which both non-genetic and genetic factors interplay. To date, 40 GWAS hits have been associated with PC risk in individuals of European descent, explaining 4.1% of the phenotypic variance.MethodsWe complemented a new conventional PC GWAS (1D) with genome spatial autocorrelation analysis (2D) permitting to prioritize low frequency variants not detected by GWAS. These were further expanded via Hi-C map (3D) interactions to gain additional insight into the inherited basis of PC. In silico functional analysis of public genomic information allowed prioritization of potentially relevant candidate variants.ResultsWe identified several new variants located in genes for which there is experimental evidence of their implication in the biology and function of pancreatic acinar cells. Among them is a novel independent variant in NR5A2 (rs3790840) with a meta-analysis p value = 5.91E−06 in 1D approach and a Local Moran’s Index (LMI) = 7.76 in 2D approach. We also identified a multi-hit region in CASC8—a lncRNA associated with pancreatic carcinogenesis—with a lowest p value = 6.91E−05. Importantly, two new PC loci were identified both by 2D and 3D approaches: SIAH3 (LMI = 18.24), CTRB2/BCAR1 (LMI = 6.03), in addition to a chromatin interacting region in XBP1—a major regulator of the ER stress and unfolded protein responses in acinar cells—identified by 3D; all of them with a strong in silico functional support.ConclusionsThis multi-step strategy, combined with an in-depth in silico functional analysis, offers a comprehensive approach to advance the study of PC genetic susceptibility and could be applied to other diseases.

Molecular mechanisms of secretory responses in nasal gland acinar cells

Molecular mechanisms of secretory responses in nasal gland acinar cells

Endocrine and exocrine pancreas pathologies crosstalk: Insulin regulates the unfolded protein response in pancreatic exocrine acinar cells in pancreatitis

Endocrine and exocrine pancreas pathologies crosstalk: Insulin regulates the unfolded protein response in pancreatic exocrine acinar cells in pancreatitis

Fatty acid ethyl ester (FAEE) associated acute pancreatitis: An ex-vivo study using human pancreatic acini

Background & aimFatty acid ethyl esters (FAEEs), are produced by non-oxidative alcohol metabolism and can cause acinar cell damage and subsequent acute pancreatitis in rodent models. Even though experimental studies have elucidated the FAEE mediated early intra-acinar events, these mechanisms have not been well studied in humans. In the present study, we evaluate the early intra-acinar events and inflammatory response in human pancreatic acinar tissues and cells in an ex-vivo model. MethodsExperiments were conducted using normal human pancreatic tissues exposed to FAEE. Subcellular fractionation was performed on tissue homogenates and trypsin and cathepsin B activities were estimated in these fractions. Acinar cell injury was evaluated by histology and immunohistochemistry. Cytokine release from exposed acinar cells was evaluated by performing Immuno-fluorescence. Serum was collected from patients with AP within the first 72 h of symptom onset for cytokine estimation using FACS. ResultsWe observed significant trypsin activation and acinar cell injury in FAEE treated tissue. Cathepsin B was redistributed from lysosomal to zymogen compartment at 30 min of FAEE exposure. IHC results indicated the presence of apoptosis in pancreatic tissue at 1 & 2hrs of FAEE exposure. We also observed a time dependent increase in secretion of cytokines IL-6, IL-8, TNF-α from FAEE treated acinar tissue. There was also a significant elevation in plasma cytokines in patents with alcohol associated AP within 72 h of symptom onset. ConclusionOur data suggest that alcohol metabolites can cause acute acinar cell damage and subsequent cytokine release which could eventually culminant in SIRS.

Perfluorooctanoic acid activates the unfolded protein response in pancreatic acinar cells.

Perfluoroalkyl substances, such as perfluorooctanoic acid (PFOA), are widely used in consumer and industrial applications. Human epidemiologic and animal studies suggest that PFOA exposure elicits adverse effects on the pancreas; however, little is known about the biological effects of PFOA in this organ. In this study, we show that PFOA treatment of mouse pancreatic acinar cells results in endoplasmic reticulum (ER) stress and activation of the protein kinase-like endoplasmic reticulum kinase (PERK), inositol-requiring kinase/endonuclease 1α (IRE1α), and activating transcription factor 6 arms of the unfolded protein response (UPR) pathway. PFOA-stimulated activation of the UPR was blocked by pretreatment with specific PERK and IRE1α inhibitors and the chemical chaperone 4-phenyl butyrate, but not the antioxidants N-acetyl- l-cysteine and Tiron. PFOA treatment led to increased cytosolic Ca+2 levels and induction of the UPR was blocked by an inhibitor of the inositol 1,4,5-trisphosphate receptor. These findings indicate that PFOA-induced ER stress may be the mechanistic trigger leading to oxidative stress in the pancreas.

Melatonin inhibits the endoplasmic reticulum stress‑induced, C/EBP homologous protein‑mediated pathway in acute pancreatitis.

Melatonin, which is mainly secreted by the pineal gland, appears to have anti‑inflammatory activities. Acute pancreatitis (AP) is characterized by inflammation and acinar cell death, and is associated with a high mortality rate. It has been reported that melatonin can alleviate cerulein (Cer) or Cer + lipopolysaccharide (LPS)‑induced inflammatory responses in AR42J rat pancreatic acinar cells (AR42J cells). CCAAT/enhancer binding protein homologous protein (CHOP) is a specific transcription factor involved in endoplasmic reticulum (ER) stress‑induced apoptosis, and regulates ER stress responses. However, the mechanisms of the anti‑inflammatory effects of melatonin' are unknown, particularly the relationship between melatonin and ER stress. Therefore, the present study aimed to investigate the anti‑inflammatory activity of melatonin in AR42J cells and analyze its molecular mechanisms during ER stress. The RNA interference method was used to determine the potential role of CHOP in AR42J cells during AP. Invitro models of AP were induced by treating AR42J cells with Cer + LPS, and pre‑treatment with melatonin was used to identify the potential anti‑inflammatory mechanisms. The cells also underwent Cell Counting Kit‑8, western blotting and reverse transcription‑quantitative PCR analyses. The expression levels of ER stress‑related molecules were rapidly activated in the early stage and increased over time in the AR42J AP models, with significant pancreatic inflammation and apoptosis. However, knockdown of CHOP expression significantly reduced apoptosis, the activation of NF‑κB and the downstream signal pathway. Moreover, cells treated with melatonin exhibited attenuated inflammation, decreased expression levels of ER stress‑associated proteins and inhibition of apoptosis. Thus, the present results suggested that melatonin may attenuate the inflammatory response by inhibiting the activation of the CHOP‑mediated pathway in AR42J cells.

Dysregulation of miR-192-5p in acute pancreatitis patients with nonalcoholic fatty liver and its functional role in acute pancreatitis progression.

Background: Nonalcoholic fatty liver disease (NAFLD) is a frequent metabolic disease and has been demonstrated to contribute to the severity of acute pancreatitis (AP). The present study aimed to investigate the aberrant expression of microRNA-192-5p (miR-192-5p) in AP patients with NAFLD, and further analyze the clinical significance and biological function of miR-192-5p in AP progression.Methods: Expression of miR-192-5p was estimated using quantitative real-time PCR (qRT-PCR). Diagnostic value of miR-192-5p was evaluated by the receiver operating characteristic curve (ROC). The effects of miR-192-5p on cell proliferation, apoptosis and inflammatory response of pancreatic acinar cells were further assessed by CCK-8 assay, flow cytometry and enzyme-linked immunosorbent assay (ELISA).Results: Circulating miR-192-5p was decreased in AP patients with NAFLD compared with those patients without NAFLD and healthy controls (P<0.05). The down-regulated expression of miR-192-5p had a relative high diagnostic accuracy to distinguish the AP patients with NAFLD from the cases without NAFLD. Furthermore, the overexpression of miR-192-5p in pancreatic acinar cells led to the decreased cell proliferation, increased cell apoptosis and suppressed inflammatory reaction (all P<0.05).Conclusion: Collectively, all data indicated that serum expression of miR-192-5p in AP patients with NAFLD is significantly decreased and serves as a candidate diagnostic biomarker. The up-regulation of miR-192-5p in pancreatic acinar cell leads to increased cell apoptosis and decreased inflammatory response, suggesting the potential of miR-192-5p as a therapeutic target of AP.

Anisodamine alleviates lipopolysaccharide-induced pancreatic acinar cell injury through NLRP3 inflammasome and NF-κB signaling pathway

Purpose: Anisodamine (An) has anti-inflammatory effects, but its role in acute pancreatitis is still unknown. This study aimed to explore the action mechanism of An pretreatment in lipopolysaccharide (LPS)-induced pancreatic acinar cells, hoping to provide a research basis for the disease treatment.Materials and methods: Pancreatic acinar cells were pretreated with An at different concentrations and then induced by LPS. The viability and apoptosis of the treated cells were measured by Cell Counting Kit-8 and flow cytometry. The releases of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-18 were measured by enzyme-linked immunosorbent assay. The expressions of thioredoxin-interacting protein (TXNIP), apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), NOD-like receptor protein 3 (NLRP3), Caspase-1, p65, and inhibitor of kappa B alpha (IκBα) in the treated cells were detected by Western blot and quantitative real-time polymerase chain reaction assay.Results: LPS promoted apoptosis of pancreatic acinar cells, suppressed cell viability, increased TNF-α, IL-1β, and IL-18 releases and the expression levels of TXNIP, ASC, NLRP3, Caspase-1, p-p65, and p-IκBα, however, such effects of LPS could be alleviated by An pretreatment with the strongest effect when the concentration of An was set at 100 μg/mL. Moreover, overexpressed NLRP3 aggravated the effects of LPS in pancreatic acinar cells, which could be reversed by pretreatment of 100 μg/mL An.Conclusion: An pretreatment attenuated LPS-induced apoptosis and inflammatory response of pancreatic acinar cells through suppressing NLRP3 and inactivating NF-κB signaling pathway, thus, it could be explored as a potential therapy for treating acute pancreatitis.

The orphan nuclear receptor SHP regulates ER stress response by inhibiting XBP1s degradation

The orphan nuclear receptor SHP (small heterodimer partner) is a well-known transcriptional corepressor of bile acid and lipid metabolism in the liver; however, its function in other tissues is poorly understood. Here, we report an unexpected role for SHP in the exocrine pancreas as a modulator of the endoplasmic reticulum (ER) stress response. SHP expression is induced in acinar cells in response to ER stress and regulates the protein stability of the spliced form of X-box-binding protein 1 (XBP1s), a key mediator of ER stress response. Loss of SHP reduces XBP1s protein level and transcriptional activity, which in turn attenuates the ER stress response during the fasting-feeding cycle. Consequently, SHP-deficient mice also are more susceptible to cerulein-induced pancreatitis. Mechanistically, we show that SHP physically interacts with the transactivation domain of XBP1s, thereby inhibiting the polyubiquitination and degradation of XBP1s by the Cullin3-SPOP (speckle-type POZ protein) E3 ligase complex. Together, our data implicate SHP in governing ER homeostasis and identify a novel posttranslational regulatory mechanism for the key ER stress response effector XBP1.

Effect of microRNA-27a-5p on apoptosis and inflammatory response of pancreatic acinar cells in acute pancreatitis by targeting PTEN.

To investigate the apoptosis and inflammatory response of microRNA-27a-5p (miR-27a-5p) in pancreatic acinar cells of acute pancreatitis (AP) and its related mechanisms. Rat pancreatic acinar cell line AR42J was treated with caerulein (10nmol/L) to construct an acute pancreatitis cell model. Quantitative real-time polymerase chain reaction was performed to measure the expression of miR-27a-5p; The miR-27a-5p mimic was transfected into cell, and the apoptosis rate of the cells was detected by flow cytometry; The levels of TNF-α, IL-1, and IL-6 in the culture supernatant were determined by enzyme-linked immunosorbent assay; TargetScans database predicted and dual luciferase reporter gene assay verified the relationship between miR-27a-5p and the phosphatase and tensin homolog deleted on chromosome 10 (PTEN); The recovery experiment explored the apoptosis and the effects of inflammatory responses. The expression of miR-27a-5p decreased gradually (P < 0.05) and the expression of PTEN increased gradually (P < 0.05) with the prolongation of acting time. Upregulation of miR-27a-5p significantly promoted cell apoptosis (P < 0.05) and inhibited inflammatory response (P < 0.05); The TargetScans database predicted that the 3'UTR of PTEN contains a base complementary to the miR-27a-5p seed region. Cotransfection of wild-type vector (PTEN-WT) with miR-27a-5p mimic or miR-27a-5p inhibitor significantly affected the relative activity of luciferase (P < 0.05), and no significant impact was observed in mutant PTEN-MUT. Compared with miR-27a-5p + pcDNA group, transfection of miR-27a-5p mimic and pcDNA-PTEN significantly increased the expression of PTEN (P < 0.05), decreased the apoptotic rate (P < 0.05), and increased the inflammatory response (P < 0.05). miR-27a-5p induced apoptosis and inhibited the inflammatory response of pancreatic acinar cells in AP by targeting PTEN.