Resveratrol protects against L-arginine-induced acute necrotizing pancreatitis in mice by enhancing SIRT1-mediated deacetylation of p53 and heat shock factor 1

Lysine acetylation and its role in the pathophysiology of acute pancreatitis

Acute pancreatitis (AP) represents a severe inflammatory condition of the exocrine pancreas, precipitating systemic organ dysfunction and potential failure. The global prevalence of acute pancreatitis is on an ascending trajectory. The condition carries a significant mortality rate during acute episodes. This underscores the imperative to elucidate the etiopathogenic pathways of acute pancreatitis, enhance comprehension of the disease's intricacies, and identify precise molecular targets coupled with efficacious therapeutic interventions. The pathobiology of acute pancreatitis encompasses not only the ectopic activation of trypsinogen but also extends to disturbances in calcium homeostasis, mitochondrial impairment, autophagic disruption, and endoplasmic reticulum stress responses. Notably, the realm of epigenetic regulation has garnered extensive attention and rigorous investigation in acute pancreatitis research over recent years. One of these modifications, lysine acetylation, is a reversible post-translational modification of proteins that affects enzyme activity, DNA binding, and protein stability by changing the charge on lysine residues and altering protein structure. Numerous studies have revealed the importance of acetylation modification in acute pancreatitis, and that it is a favorable target for the design of new drugs for this disease. This review centers on lysine acetylation, examining the strides made in acute pancreatitis research with a focus on the contributory role of acetylomic alterations in the pathophysiological landscape of acute pancreatitis, thereby aiming to delineate novel therapeutic targets and advance the development of more efficacious treatment modalities.

Molecular mechanism and potential role of mitophagy in acute pancreatitis

Acute pancreatitis (AP) is a multifaceted inflammatory disorder stemming from the aberrant activation of trypsin within the pancreas. Despite the contribution of various factors to the pathogenesis of AP, such as trypsin activation, dysregulated increases in cytosolic Ca2+ levels, inflammatory cascade activation, and mitochondrial dysfunction, the precise molecular mechanisms underlying the disease are still not fully understood. Mitophagy, a cellular process that preserves mitochondrial homeostasis under stress, has emerged as a pivotal player in the context of AP. Research suggests that augmenting mitophagy can mitigate pancreatic injury by clearing away malfunctioning mitochondria. Elucidating the role of mitophagy in AP may pave the way for novel therapeutic strategies. This review article aims to synthesize the current research findings on mitophagy in AP and underscore its significance in the clinical management of the disorder.

Myricetin ameliorates the severity of pancreatitis in mice by regulating cathepsin B activity and inflammatory cytokine production

Cathepsin B (CTSB) and inflammatory cytokines are critical in initiating and developing pancreatitis. Calcineurin, a central calcium (Ca2+)-responsive signaling molecule, mediates acinar cell death and inflammatory responses leading to pancreatitis. However, the detailed mechanisms for regulating CTSB activity and inflammatory cytokine production are unknown. Myricetin (MC) exhibits various biological activities, including anti-inflammatory effects. Here, we aimed to investigate MC effects on pancreatitis and the underlying mechanisms. Prophylactic and therapeutic MC treatment ameliorated the severity of cerulein-, L-arginine-, and PDL-induced acute pancreatitis (AP). The inhibition of CTSB activity by MC was mediated via decreased calcineurin activity and macrophage infiltration, not neutrophils infiltration, into the pancreas. Additionally, calcineurin activity inhibition by MC prevented the phosphorylation of Ca2+/CaM-dependent protein kinase kinase 2 (CaMKK2) during AP, resulting in the inhibition of CaMKIV phosphorylation and adenosine monophosphate-activated protein kinase (AMPK) dephosphorylation. Furthermore, MC reduced nuclear factor-κB activation by modulating the calcineurin-CaMKIV-IKKα/β-Iκ-Bα and calcineurin-AMPK-sirtuin1 axes, resulting in reduced production of tumor necrosis factor-α, interleukin (IL)-1β, and IL-6. Our results showed that MC alleviated AP severity by inhibiting acinar cell death and inflammatory responses, suggesting that MC as a calcineurin and CaMKK2 signaling modulator may be a potential treatment for AP.

Pinocembrin's protective effect against acute pancreatitis in a rat model: The correlation between TLR4/NF-κB/NLRP3 and miR-34a-5p/SIRT1/Nrf2/HO-1 pathways

BACKGROUND

Acute pancreatitis (APS) is a prevalent acute pancreatic inflammation, where oxidative stress, inflammatory signaling pathways, and apoptosis activation contribute to pancreatic injury.

METHODS

Pinocembrin, the predominant flavonoid in propolis, was explored for its likely shielding effect against APS provoked by two intraperitoneal doses of L-arginine (250 mg / 100 g) in a rat model.

RESULTS

Pinocembrin ameliorated the histological and immunohistochemical changes in pancreatic tissues and lowered the activities of pancreatic amylase and lipase that were markedly elevated with L-arginine administration. Moreover, pinocembrin reinstated the oxidant/antioxidant equilibrium, which was perturbed by L-arginine, and boosted the pancreatic levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1). Pinocembrin markedly reduced the elevation in serum C-reactive protein (CRP) level induced by L-arginine. Additionally, it decreased the expression of high motility group box protein 1 (HMGB1), toll-like receptor 4 (TLR4), nuclear factor kappa B (NF-κB), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and NOD-like receptor (NLR) Family Pyrin Domain Containing 3 (NLRP3) inflammasome in the pancreas. Furthermore, it also reduced myeloperoxidase (MPO) activity. Pinocembrin markedly downregulated miR-34a-5p expression and upregulated the protein levels of peroxisome proliferator-activated receptor alpha (PPAR-α) and Sirtuin 1 (SIRT1) and the gene expression level of the inhibitor protein of NF-κB (IκB-α), along with normalizing the Bax/Bcl-2 ratio.

CONCLUSIONS

Pinocembrin notably improved L-arginine-induced APS by its antioxidant, anti-inflammatory, and anti-apoptotic activities. Pinocembrin exhibited a protective role in APS by suppressing inflammatory signaling via the TLR4/NF-κB/NLRP3 pathway and enhancing cytoprotective signaling via the miR-34a-5p/SIRT1/Nrf2/HO-1 pathway.

Sitagliptin ameliorates L-arginine-induced acute pancreatitis via modulating inflammatory cytokines expression and combating oxidative stress

Background

Acute pancreatitis (AP) is an inflammatory condition that resolves spontaneously, but occasionally, develops into systemic inflammation, organ failure and mortality. Oxidative stress and activation of inflammatory pathways represent major players in AP pathogenesis. Current management of AP relies on attenuating injuries to the pancreas and putting the inflammatory process under control. In this study, we investigated the role of sitagliptin in modulating L-arginine-induced AP in rats.

Methods

Swiss rats were subdivided into a healthy control group, AP group (a single dose of L-arginine 250 mg/100 g, intraperitoneal), and sitagliptin + L-arginine-treated group (10 mg sitagliptin/kg body weight/day, orally). Sitagliptin treatment started 1 hour after L-arginine injection and continued for 3days. Biochemical and histopathological investigations were performed on serum and tissue samples collected from test animals.

Results

L-arginine increased pancreatic meyloperoxidase and serum amylase- and lipase activities and serum levels of TNF-α, LT-α, IFN-γ, IL-1α/β, IL-6, IL-10, IL-12, and IL-15. AP animals showed elevated MDA and NO and decreased GSH and serum calcium levels. Histopathological changes were observed by H&E staining. Sitagliptin treatment significantly ameliorated these biochemical and histological changes diminishing the signs of AP.

Conclusion

Sitagliptin treatment was effective in ameliorating L-arginine-induced AP which can be regarded to its anti-inflammatory and antioxidant effect.

Functional role of IL-19 in a mouse model of L-arginine-induced pancreatitis and related lung injury

IL-19 is a member of IL-10 family and is mainly produced by macrophages. Acute pancreatitis (AP) is an inflammatory disease characterized by acinar cell injury and necrosis. In the present study, the role of IL-19 in AP and AP-associated lung injury in mice was explored using L-arginine-induced pancreatitis. Experimental pancreatitis was induced by intraperitoneal injection of L-arginine in wild-type (WT) and IL-19 gene-deficient (IL-19 KO) mice. Among the mice treated with L-arginine, the serum amylase level was significantly increased in the IL-19 KO mice, and interstitial edema, analyzed using hematoxylin and eosin-stained sections, was aggravated mildly in IL-19 KO mice compared with WT mice. Furthermore, the mRNA expression of tumor necrosis factor-α was significantly upregulated in IL-19 KO mice treated with L-arginine compared with WT mice treated with L-arginine. IL-19 mRNA was equally expressed in the pancreases of both control and L-arginine-treated WT mice. The conditions of lung alveoli were then evaluated in WT and IL-19 KO mice treated with L-arginine. In mice with L-arginine-induced pancreatitis, the alveolar area was remarkedly decreased, and expression of lung myeloperoxidase was significantly increased in IL-19 KO mice compared with WT mice. In the lungs, the mRNA expression of IL-6 and inducible nitric oxide synthase was significantly increased in IL-19 KO mice compared with WT mice. In summary, IL-19 was proposed to alleviate L-arginine-induced pancreatitis by regulating TNF-α production and to protect against AP-related lung injury by inhibiting neutrophil migration.

Resveratrol-Based Liposomes Improve Cardiac Remodeling Induced by Isoproterenol Partially by Modulating MEF2, Cytochrome C and S100A1 Expression

Isoproterenol (ISO), a chemically synthesized catecholamine, belongs to β-adrenoceptor agonist used to treat bradycardia. The β-adrenergic agonist is an essential regulator of myocardial metabolism and contractility; however, excessive exposure to ISO can initiate oxidative stress and inflammation. This study aims to investigate the molecular mechanisms underlying ISO-induced cardiac remodeling, the protective efficacy of resveratrol (RSVR), and its liposomal formulation (L-RSVR) against such cardiac change. Wistar albino rats were evenly divided into 4 groups. Control group, ISO group received ISO (50 mg/kg, s.c.) twice a week for 2 weeks, and RSVR- and L-RSVR-treated groups in which rats received either RSVR or L-RSVR (20 mg/kg/day, p.o.) along with ISO for 2 weeks. ISO caused a significant elevation of the expression levels of BAX and MEF2 mRNA, S100A1 and cytochrome C proteins, as well as DNA fragmentation in cardiac tissue compared to the control group. Treatment with either RSVR or L-RSVR for 14 days significantly ameliorated the damage induced by ISO, as evidenced by the improvement of all measured parameters. The present study shows that L-RSVR provides better cardio-protection against ISO-induced cardiac injury in rats, most likely through modulation of cardiac S100A1 protein expression and inhibition of inflammation and apoptosis.

Still water run deep: Therapeutic TP effect of ucMSC-Ex via regulating mTOR to enhance autophagy

Our previous study confirmed that umbilical cord mesenchymal stem cells-exosomes (ucMSC-Ex) inhibit apoptosis of pancreatic acinar cells to exert protective effects. However, the relationship between apoptosis and autophagy in traumatic pancreatitis (TP) has rarely been reported. We dissected the transcriptomics after pancreatic trauma and ucMSC-Ex therapy by high-throughput sequencing. Additionally, we used rapamycin and MHY1485 to regulate mTOR. HE, inflammatory factors and pancreatic enzymatic assays were used to comprehensively determine the local versus systemic injury level, fluorescence staining and electron microscopy were used to detect the effect of autophagy, and observe the expression levels of autophagy-related markers at the gene and protein levels. High-throughput sequencing identified that autophagy played a crucial role in the pathophysiological process of TP and ucMSC-Ex therapy. The results of electron microscopy, immunofluorescence staining, polymerase chain reaction and western blot suggested that therapeutic effect of ucMSC-Ex was mediated by activation of autophagy in pancreatic acinar cells through inhibition of mTOR. ucMSC-Ex can attenuate pancreas injury by inhibiting mTOR to regulate acinar cell autophagy after TP. Future studies will build on the comprehensive sequencing of RNA carried by ucMSC-Ex to predict and verify specific non-coding RNA.

Hesperidin Alleviates Acute Necrotizing Pancreatitis by Activating SIRT1 - Molecular Docking, Molecular Dynamics Simulation, and Experimental Validation

BACKGROUND

Acute necrotizing pancreatitis is a serious pancreatic injury with limited effective treatments. This study aims to investigate the therapeutic effects of hesperidin on Larginine- induced acute pancreatitis and its potential targets.

METHODS

The authors induced acute pancreatitis in mice by administering two hourly intraperitoneal injections of L-arginine-HCl, and evaluated the impact of hesperidin on pancreatic and lung tissues, plasma amylase activity, and myeloperoxidase content. Additionally, necrosis and mitochondrial function was tested in primary pancreatic acinar cells. The interactions between hesperidin and proteins involved in necrosis and mitochondrial dysfunction were further invested using in silico molecular docking and molecular dynamic simulations.

RESULTS

Hesperidin effectively ameliorated the severity of acute necrotizing pancreatitis by reducing plasma amylase, pancreatic MPO, serum IL-6 levels, pancreatic edema, inflammation, and pancreatic necrosis. Hesperidin also protected against acute pancreatitis-associated lung injury and prevented acinar cell necrosis, mitochondrial membrane potential loss, and ATP depletion. In addition, hesperidin exhibited a high binding affinity with SIRT1 and increased the protein levels of SIRT1. The SIRT1 inhibitor EX527 abolished the protective effect of hesperidin against necrosis in acinar cells.

CONCLUSION

These findings indicate that hesperidin alleviates the severity of acute necrotizing pancreatitis by activating SIRT1, which may provide insight into the mechanisms of natural compounds in treating AP. Hesperidin has potential as a therapeutic agent for acute necrotizing pancreatitis and provides a new approach for novel therapeutic strategies.

AKBA alleviates experimental pancreatitis by inhibiting oxidative stress in Macrophages through the Nrf2/HO-1 pathway

BACKGROUND

Acute pancreatitis (AP) is an inflammatory condition of the pancreas characterized by oxidative stress and inflammation in its pathophysiology. Acetyl-11-keto-β-boswellic acid (AKBA) is an active triterpenoid with antioxidant activity. This article seeks to assess the impact of AKBA on AP and investigate its underlying mechanisms.

METHODS

AP was induced in wild-type, Lyz2+/cre Nrf2fl/fl mice and Pdx1+/cre Nrf2fl/fl mice by caerulein. Serum amylase and lipase levels, along with histological grading, were utilized to evaluate the severity of AP. Murine bone marrow-derived macrophages (BMDMs) were isolated, cultured, and polarized to the M1 subtype. Flow cytometry and ELISA were utilized to identify the macrophage phenotype. Alterations in oxidative stress damage and intracellular ROS were observed. Nrf2/HO-1 signaling pathways were also evaluated.

RESULTS

In a caerulein-induced mouse model of AP, treatment with AKBA reduced blood amylase and lipase activity and ameliorated pancreatic tissue histological and pathological features. Furthermore, AKBA significantly mitigated oxidative stress-induced damage and induced the expression of Nrf2 and HO-1 protein. Additionally, by using conditional knockout mice (Lyz2+/cre Nrf2fl/fl and Pdx1+/cre Nrf2fl/fl mice), we verified that Nrf2 primarily functions in macrophages rather than acinar cells. In vitro, AKBA inhibits pro-inflammatory M1-subtype macrophage polarization and reduces ROS generation through Nrf2/HO-1 oxidative stress pathway. Moreover, the protective effects of AKBA against AP were abolished in myeloid-specific Nrf2-deficient mice and BMDMs. Molecular docking results revealed interactions between AKBA and Nrf2.

CONCLUSION

Our results confirm that AKBA exerts protective effects against AP in mice by inhibiting oxidative stress in macrophages through the Nrf2/HO-1 Pathway.

Vitamin E protects against the modulation of TNF-α-AMPK axis and inhibits pancreas injury in a rat model of L-arginine-induced acute necrotising pancreatitis

BACKGROUND

Acute pancreatitis (AP) associated with the modulation of TNF-α-AMPK axis in the presence and absence of vitamin E has not been investigated before.

MATERIAL AND METHODS

Rats were either injected with L-arginine (2.5 gm/kg) before being sacrificed after 48 h or were pre-treated with vitamin E (60 mg/kg) and continued receiving vitamin E until the end of the experiment.

RESULTS

AP was developed as demonstrated by infiltration of inflammatory cells and profound pancreas tissue damage, which were substantially protected by vitamin E. In addition, L-arginine injections significantly (p < .0001) increased the expression of TNF-α mRNA and protein, and decreased phospho-AMPK and IL-10 mRNA and protein that was significantly (p < .0001) protected by vitamin E. Furthermore, vitamin E inhibited L-arginine-induced blood levels of LDH, amylase, and myeloperoxidase.

CONCLUSIONS

L-arginine-induced acute pancreatitis modulates TNF-α-AMPK axis, IL-10 and other AP biomarkers, which is protected by vitamin E; thus, may offer therapeutic potential in humans.

The sirtuin family in health and disease

Sirtuins (SIRTs) are nicotine adenine dinucleotide(+)-dependent histone deacetylases regulating critical signaling pathways in prokaryotes and eukaryotes, and are involved in numerous biological processes. Currently, seven mammalian homologs of yeast Sir2 named SIRT1 to SIRT7 have been identified. Increasing evidence has suggested the vital roles of seven members of the SIRT family in health and disease conditions. Notably, this protein family plays a variety of important roles in cellular biology such as inflammation, metabolism, oxidative stress, and apoptosis, etc., thus, it is considered a potential therapeutic target for different kinds of pathologies including cancer, cardiovascular disease, respiratory disease, and other conditions. Moreover, identification of SIRT modulators and exploring the functions of these different modulators have prompted increased efforts to discover new small molecules, which can modify SIRT activity. Furthermore, several randomized controlled trials have indicated that different interventions might affect the expression of SIRT protein in human samples, and supplementation of SIRT modulators might have diverse impact on physiological function in different participants. In this review, we introduce the history and structure of the SIRT protein family, discuss the molecular mechanisms and biological functions of seven members of the SIRT protein family, elaborate on the regulatory roles of SIRTs in human disease, summarize SIRT inhibitors and activators, and review related clinical studies.

Phytochemicals with protective effects against acute pancreatitis: a review of recent literature

CONTEXT

Acute pancreatitis (AP) is an acute abdominal inflammatory disease with episodes ranging from mild to fulminant symptoms which could include necrosis, systemic inflammation and multiple organ dysfunction. Increasing experimental evidence demonstrates that specific bioactive ingredients from natural plants have a favourable therapeutic effect on AP.

OBJECTIVE

The objective of this review is to summarize the protective effects and potential mechanisms of action of phytochemicals on the attenuation of AP.

METHODS

Experimental studies in vivo or in vitro between January 2016 and June 2021 were sought in PubMed and Web of Science using the following search terms: ('phytochemicals' OR 'medicinal plant' OR 'traditional medicine') AND ('pancreatitis' OR 'pancreatic damage' OR 'pancreatic injury'). Data concerning the basic characteristics of phytochemicals, therapeutic dose and potential molecular mechanisms related to AP were extracted in this study.

RESULTS

A total of 30 phytochemicals with potential therapeutic effects were reviewed and summarized systematically. According to their molecular pathways in AP, the underlying mechanisms of the phytochemicals were illustrated in detail.

DISCUSSION AND CONCLUSIONS

The phytochemicals with anti-inflammatory and antioxidant abilities may be efficient candidate drugs for AP treatment. Importantly, more preclinical investigations are needed to illustrate the efficacy of future phytochemicals.

A novel resveratrol analog upregulates sirtuin 1 and inhibits inflammatory cell infiltration in acute pancreatitis

Acute pancreatitis (AP), an inflammatory disorder of the pancreas, is a complicated disease without specific drug therapy. (R)-4,6-dimethoxy-3-(4-methoxy phenyl)-2,3-dihydro-1H-indanone [(R)-TML104] is a synthesized analog of the natural product resveratrol sesquiterpenes (±) -isopaucifloral F. This study aimed to investigate the effect and underlying mechanism of (R)-TML104 on AP. The experimental AP model was induced by caerulein hyperstimulation in BALB/c mice. (R)-TML104 markedly attenuated caerulein-induced AP, as evidenced by decreased pancreatic edema, serum amylase levels, serum lipase levels, and pancreatic myeloperoxidase activity. In addition, (R)-TML104 significantly inhibited the expression of pancreatic chemokines C-C motif chemokine ligand 2 and macrophage inflammatory protein-2 and the infiltration of neutrophils and macrophages. Mechanistically, (R)-TML104 activated AMP-activated protein kinase and induced sirtuin 1 (SIRT1) expression. (R)-TML104 treatment markedly induced the SIRT1-signal transducer and activator of transcription 3 (STAT3) interaction and reduced acetylation of STAT3, thus inhibiting the inflammatory response mediated by the interleukin 6-STAT3 pathway. The effect of (R)-TML104 on SIRT1-STAT3 interaction was reversed by treatment with a SIRT1 inhibitor selisistat (EX527). Together, our findings indicate that (R)-TML104 alleviates experimental pancreatitis by reducing the infiltration of inflammatory cells through modulating SIRT1.

Ulinastatin Attenuates LPS-Induced Inflammation and Inhibits Endoplasmic Reticulum Stress-Induced Apoptosis in Renal Tubular Epithelial Cells via Regulation of the TLR4/NF-κB and Nrf2/HO-1 Pathways

Acute kidney injury (AKI) is one of the most common diseases in patients treated in intensive care units. This study was intended to explore the underlying mechanism by which ulinastatin (UTI) influenced the inflammation and apoptosis of renal tubular epithelial cells, HK-2.The effects of UTI on the cell viability of HK-2 cells were first measured by MTT and lactate dehydrogenase (LDH) detection kit. The apoptosis and inflammation of HK-2 cells were then determined by TUNEL, western blot, ELISA, and RT-qPCR. Then, the proteins in the Toll-like receptor 4 (TLR4)/nuclear factor κB (NF-κB) and nuclear factor erythroid 2-related factor 2 (Nrf2)/Heme oxygenase 1 (HO-1) signaling pathways were measured by western blot for confirming the relationship between UTI and these pathways. Finally, Nrf-2 inhibitor ML385 and TLR4 activator CCL-34 were respectively used on LPS-induced HK-2 cells exposed to UTI for the conduction of gain-of-function and loss-of-function assays.UTI treatment boosted the cell viability of HK-2 cells damaged by LPS. Furthermore, UTI exposure cut down the apoptosis rate and inhibited the expression inflammatory factors of HK-2 cells induced by LPS. UTI treatment decreased the expression of proteins in the TLR4/NF-κB pathway, increased the HO-1 expression, and prompted the translocation of Nrf2 from the cytoplasm to the nucleus. The alleviated effects of UTI on inflammation and apoptosis LPS-induced HK-2 cells were abolished by ML385 and TLR4, respectively.UTI attenuates LPS-induced inflammation and inhibits endoplasmic reticulum stress-induced apoptosis in renal tubular epithelial cells by regulating TLR4/NF-κB and Nrf2/HO-1 pathways.

The pleiotropic neuroprotective effects of resveratrol in cognitive decline and Alzheimer's disease pathology: From antioxidant to epigenetic therapy

While the elderly segment of the population continues growing in importance, neurodegenerative diseases increase exponentially. Lifestyle factors such as nutrition, exercise, and education, among others, influence ageing progression, throughout life. Notably, the Central Nervous System (CNS) can benefit from nutritional strategies and dietary interventions that prevent signs of senescence, such as cognitive decline or neurodegenerative diseases such as Alzheimer's disease and Parkinson's Disease. The dietary polyphenol Resveratrol (RV) possesses antioxidant and cytoprotective effects, producing neuroprotection in several organisms. The oxidative stress (OS) occurs because of Reactive oxygen species (ROS) accumulation that has been proposed to explain the cause of the ageing. One of the most harmful effects of ROS in the cell is DNA damage. Nevertheless, there is also evidence demonstrating that OS can produce other molecular changes such as mitochondrial dysfunction, inflammation, apoptosis, and epigenetic modifications, among others. Interestingly, the dietary polyphenol RV is a potent antioxidant and possesses pleiotropic actions, exerting its activity through various molecular pathways. In addition, recent evidence has shown that RV mediates epigenetic changes involved in ageing and the function of the CNS that persists across generations. Furthermore, it has been demonstrated that RV interacts with gut microbiota, showing modifications in bacterial composition associated with beneficial effects. In this review, we give a comprehensive overview of the main mechanisms of action of RV in different experimental models, including clinical trials and discuss how the interconnection of these molecular events could explain the neuroprotective effects induced by RV.

Augmentation of the heat shock axis during exceptional longevity in Ames dwarf mice

How the heat shock axis, repair pathways, and proteostasis impact the rate of aging is not fully understood. Recent reports indicate that normal aging leads to a 50% change in several regulatory elements of the heat shock axis. Most notably is the age-dependent enhancement of inhibitory signals associated with accumulated heat shock proteins and hyper-acetylation associated with marked attenuation of heat shock factor 1 (HSF1)–DNA binding activity. Because exceptional longevity is associated with increased resistance to stress, this study evaluated regulatory check points of the heat shock axis in liver extracts from 12 months and 24 months long-lived Ames dwarf mice and compared these findings with aging wild-type mice. This analysis showed that 12M dwarf and wild-type mice have comparable stress responses, whereas old dwarf mice, unlike old wild-type mice, preserve and enhance activating elements of the heat shock axis. Old dwarf mice thwart negative regulation of the heat shock axis typically observed in usual aging such as noted in HSF1 phosphorylation at Ser307 residue, acetylation within its DNA binding domain, and reduction in proteins that attenuate HSF1–DNA binding. Unlike usual aging, dwarf HSF1 protein and mRNA levels increase with age and further enhance by stress. Together these observations suggest that exceptional longevity is associated with compensatory and enhanced HSF1 regulation as an adaptation to age-dependent forces that otherwise downregulate the heat shock axis.

CTRP3 ameliorates cerulein-induced severe acute pancreatitis in mice via SIRT1/NF-κB/p53 axis

Severe acute pancreatitis (SAP) is a common and life-threatening clinical acute abdominal disease. C1q/tumor necrosis factor-related protein 3 (CTRP3), a novel paralog of adiponectin, has been identified as a crucial regulator in multiple types of inflammatory disorders. However, the biological role of CTRP3 in SAP remains poorly understood. The present study aimed to characterize the role of CTRP3 in SAP and illuminate the potential mechanisms involved. In the current study, SAP mouse models were induced by seven hourly intraperitoneal injection of cerulein (50 μg/kg) and an immediate intraperitoneal injection of lipopolysaccharide (10 mg/kg) after the last cerulein administration. Histological examination and serological analysis demonstrated that SAP mouse models were successfully established. Herein, we found that CTRP3 expression was significantly decreased in the pancreatic tissues of SAP mice compared with normal control mice. Furthermore, we explored the effects of CTRP3 rescue in SAP mice and discovered that CTRP3 overexpression attenuated pathological lesions, inhibited inflammatory mediator release and repressed acinar cell apoptosis. Notably, mechanistic studies revealed that CTRP3 overexpression suppressed NF-κB p65 phosphorylation and p53 acetylation to alleviate cerulein-induced SAP in mouse models through activation of silent information regulator 1 (SIRT1), a nicotinamide adenine dinucleotide-dependent protein deacetylase. Collectively, our data indicate that CTRP3 may exert its protective effects in SAP mice via regulation of SIRT1-mediated NF-κB and p53 signaling pathways, implying a promising therapeutic strategy against SAP.

Resveratrol Suppresses Severe Acute Pancreatitis-Induced Microcirculation Disturbance through Targeting SIRT1-FOXO1 Axis

BACKGROUND

Resveratrol (RSV), one of the SIRT1 agonists, has the ability of alleviating severe acute pancreatitis (SAP); however, the concrete protective mechanism remains unknown. It is noteworthy that microcirculation disturbance plays a vital role in SAP, and the SIRT1/FOX1 axis can regulate microcirculation. Therefore, this study is aimed at ascertaining what is the underlying mechanism of the protective effect of RSV on SAP, and whether it is associated with alleviating microcirculation disturbance by regulating the SIRT1/FOX1 axis.

METHOD

The model of SAP was induced by retrograde injection of sodium taurodeoxycholate into the bile duct of the rats. The pancreatic wet/dry weight, ET/NO, and TXB2/6-keto-PGF1α ratios; microcirculatory function; and SIRT1 activity were examined. ELISA was used to examine the serum level of lipase, amylase, hemorheology, ET, NO, TXB2, and 6-keto-PGF1α and the content of SIRT1, VEGF, Ang I, and Ang II in the pancreas. RT-PCR was used to examine the mRNA level of VEGF, Ang I, and Ang II. Western blotting was used to detect SIRT1, FOXO1, and acetyl-FOXO1. Immunoprecipitation was used to examine the interaction of SIRT1 and FOXO1.

RESULTS

Resveratrol can significantly decrease the expression of lipase, amylase, acetyl-FOXO1, VEGF, Ang II, ET, NO, TXB2, and 6-keto-PGF1α and the ratio of wet/dry weight, ET/NO, and TXB2/6-keto-PGF1α by improving microcirculatory dysfunction and blood viscosity in SAP. Moreover, resveratrol can also promote the interaction of SIRT1 and FOXO1 and increase SIRT1 activity and the expression of SIRT1 and Ang I. The SIRT1 inhibitor, Sirtinol (EX527), obliviously reversed the effects of RSV on SAP.

CONCLUSION

Resveratrol can protect rats against SAP, and its protective mechanism is associated with suppressing microcirculation disturbance through activating SIRT1-FOXO1 axis.

Resveratrol supplementation and acute pancreatitis: A comprehensive review

Resveratrol, a natural polyphenolic ingredient extracted from herbs, suppresses oxidative stress and inflammation. We performed a comprehensive review to find any evidence about the effects of Resveratrol on acute pancreatitis (AP). Resveratrol has been found to directly impact cytokine generation. As these factors play a crucial role in the pathophysiology of AP, resveratrol might attenuate AP and its complications. Mechanistically, resveratrol exerts its pharmacological effects through anti-inflammatory and antioxidant mechanisms via interaction with different signaling molecules and transcription factors. Indeed, resveratrol might prove to be an effective therapeutic component for AP treatment in the future. In this review, we shed light on potential most recent pathways through which resveratrol might impact the management and control of AP.

Abdominal paracentesis drainage attenuates severe acute pancreatitis by enhancing cell apoptosis via PI3K/AKT signaling pathway

Our previous studies have shown that abdominal paracentesis drainage (APD) is a safe and effective strategy for patients with severe acute pancreatitis (SAP). However, the underlying mechanisms behind APD treatment remain poorly understood. Given that apoptosis is a critical pathological response of SAP, we here aim to investigate the effect of APD on cell apoptosis in pancreatic tissues during SAP and to explore its potential molecular mechanism. SAP was induced by 5% sodium-taurocholate retrograde while APD group was inserted a drainage tube into the right lower abdomen of rats immediately after SAP induction. Histopathological staining, serum amylase, endotoxin and inflammatory mediators were measured. Cell apoptosis, apoptosis-related proteins and signaling pathway were also evaluated. Our results demonstrated that APD treatment significantly attenuated pancreatic damage and decreased the serum levels of amylase, endotoxin, TNF-α, IL-1 and IL-6 in rats with SAP. Notably, APD treatment enhanced cell apoptosis and reduced necrosis in pancreatic tissues, as evidenced by Tunnel staining, the increased pro-apoptosis proteins (Cleaved-caspase-3 and bax) and decreased anti-apoptosis protein (Bcl-2). Moreover, the effect of APD on cell apoptosis was further confirmed by the regulatory pathway of PI3K/AKT and NF-kB signaling pathway. These results suggest that APD attenuates the severity of SAP by enhancing cell apoptosis via suppressing PI3K/AKT signaling pathway. Our findings provide new insights for understanding the effectiveness of APD in patients with SAP.

Vinpocetine ameliorates L-arginine induced acute pancreatitis via Sirt1/Nrf2/TNF pathway and inhibition of oxidative stress, inflammation, and apoptosis

OBJECTIVES

Acute pancreatitis (AP) is a common severe critical illness with a high mortality rate. We aimed to study the effect of vinpocetine (Vinpo) in the treatment of AP because of its anti-inflammatory, antioxidant, and antiapoptotic effects.

MATERIALS AND METHODS

Thirty two adult male albino Wistar rats were randomized to four groups: control group, Vinpo group (20 mg/kg.P.O.), l-arginine group (two intraperitoneal injections of l-arginine 2.5 g/kg, 1 h apart), and Vinpo + L-arginine group. Vinpo administration was once daily for 7 consecutive days and started 1 h later after l-arginine administration. We measured serum enzyme biomarkers (lipase and amylase), levels of pancreatic malondialdehyde (MDA), total antioxidant capacity (TAC), reduced glutathione (GSH), total sulfhydryl (T-SH), total nitrite/nitrate (NOx), Interluken-6 (IL-6), tumor necrosis factor-alpha (TNF-α), Nuclear factor (erythroid-derived 2)-like 2 (Nrf2), Sirtuin type 1 (Sirt1), and caspase-3 activity. Furthermore; histological changes, anti-insulin, and inducible nitric oxide synthase (iNOS) immuno-expressions were examined.

RESULTS

l-arginine group displayed AP as manifested by a significant increase in serum lipase and amylase, MDA, NOx, IL-6, TNF-α, caspase-3 with iNOS immuno-expression. Histological changes indicating marked pancreatic injury were observed together with a significant decrease in TAC, GSH, T-SH, Nrf2, Sirt1 levels, and anti-insulin immuno-expression. Vinpo showed a significant amelioration in all parameters.

CONCLUSION

Vinpo possesses potent ameliorative effects against AP by decreasing oxidative stress, inflammatory process, and apoptosis through regulation of the Sirt1/Nrf2/TNF-α pathway.

The Critical Role of SIRT1 in Parkinson's Disease: Mechanism and Therapeutic Considerations

Silence information regulator 1 (SIRT1), a member of the sirtuin family, targets histones and many non-histone proteins and participates in various physiological functions. The enzymatic activity of SIRT1 is decreased in patients with Parkinson’s disease (PD), which may reduce their ability to resist neuronal damage caused by various neurotoxins. As far as we know, SIRT1 can induce autophagy by regulating autophagy related proteins such as AMP-activated protein kinase, light chain 3, mammalian target of rapamycin, and forkhead transcription factor 1. Furthermore, SIRT1 can regulate mitochondrial function and inhibit oxidative stress mainly by maintaining peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) in a deacetylated state and thus maintaining a constant level of PGC-1α. Other studies have demonstrated that SIRT1 may play a role in the pathophysiology of PD by regulating neuroinflammation. SIRT1 deacetylases nuclear factor-kappa B and thus reduces its transcriptional activity, inhibits inducible nitric oxide synthase expression, and decreases tumor necrosis factor-alpha and interleukin-6 levels. SIRT1 can also upregulate heat shock protein 70 by deacetylating heat shock factor 1 to increase the degradation of α-synuclein oligomers. Few studies have focused on the relationship between SIRT1 single nucleotide polymorphisms and PD risk, so this topic requires further research. Based on the neuroprotective effects of SIRT1 on PD, many in vitro and in vivo experiments have demonstrated that some SIRT1 activators, notably resveratrol, have potential neuroprotective effects against dopaminergic neuronal damage caused by various neurotoxins. Thus, SIRT1 plays a critical role in PD development and might be a potential target for PD therapy.

Drug discovery and formulation development for acute pancreatitis

Acute pancreatitis is a sudden inflammation and only last for a short time, but might lead to a life-threatening emergency. Traditional drug therapy is an essential supportive method for acute pancreatitis treatment, yet, failed to achieve satisfactory therapeutic outcomes. To date, it is still challenging to develop therapeutic medicine to redress the intricate microenvironment promptly in the inflamed pancreas, and more importantly, avoid multi-organ failure. The understanding of the acute pancreatitis, including the causes, mechanism, and severity judgment, could help the scientists bring up more effective intervention and treatment strategies. New formulation approaches have been investigated to precisely deliver therapeutics to inflammatory lesions in the pancreas, and some even could directly attenuate the pancreatic damages. In this review, we will briefly introduce the involved pathogenesis and underlying mechanisms of acute pancreatitis, as well as the traditional Chinese medicine and the new drug option. Most of all, we will summarize the drug delivery strategies to reduce inflammation and potentially prevent the further development of pancreatitis, with an emphasis on the bifunctional nanoparticles that act as both drug delivery carriers and therapeutics.

Cashew (Anacardium occidentale L.) Nuts Modulate the Nrf2 and NLRP3 Pathways in Pancreas and Lung after Induction of Acute Pancreatitis by Cerulein

BACKGROUND

One of the most common co-morbidities, that often leads to death, associated with acute pancreatitis (AP) is represented by acute lung injury (ALI). While many aspects of AP-induced lung inflammation have been investigated, the involvement of specific pathways, such as those centered on nuclear factor E2-related factor 2 (Nrf2) and nucleotide-binding domain leucine-rich repeat (NLR) and pyrin domain containing receptor 3 (NLRP3), has not been fully elucidated.

METHODS

To investigate the effect of cashew (Anacardium occidentale L.) nuts on pancreatic and lung injury induced by cerulein injection, cerulein (50 μg/kg) was administered to CD1 mice for 10 h. Oral treatment with cashew nuts at a dose of 100 mg/kg was given 30 min and 2 h after the first cerulein injection. One hour after the final cerulein injection, mice were euthanized and blood, lung and pancreatic tissue samples were collected.

RESULTS

Cashew nuts were able to (1) reduce histological damage; (2) mitigate the induction of mast cell degranulation as well as the activity of myeloperoxidase and malondialdehyde; (3) decrease the activity levels of amylase and lipase as well as the levels of pro-inflammatory cytokines; and (4) enhance the activation of the Nrf2 pathway and suppress the activation of the NLRP3 pathway in response to cerulein in both pancreas and lung.

CONCLUSIONS

Cashew nuts could have a beneficial effect not only on pancreatitis but also on lung injury induced by cerulein.

Possible mechanisms mediating the protective effect of cilostazol in L-arginine induced acute pancreatitis in rats: role of cGMP, cAMP, and HO-1

Acute pancreatitis (AP) is an inflammatory disorder with a high mortality rate. Cilostazol is a selective phosphodiesterase-3 inhibitor drug that is commonly used as an antiplatelet, antithrombotic, and vasodilator drug. It exhibits antioxidant, anti-inflammatory, and anti-apoptotic activities, but its effect on AP has not been fully elucidated yet. The present study aimed to investigate the effects of cilostazol on L-arginine-induced AP and the possible protective mechanisms. A rat model of AP was established by a single i.p. injection of 3-g/kg L-arginine on day 13 of the experiment. The treated groups received a single daily oral dose of either 100 or 300 mg/kg/day for 14 consecutive days. Rats with AP showed histopathological changes of pancreatic tissue injury together with increased serum amylase enzyme activity and decreased serum insulin, pancreatic adiponectin, and cGMP levels. Moreover, AP rats showed increased pancreatic inflammatory biomarker (TNF-α, VCAM-1, and MPO) levels with decreased anti-inflammatory IL-10 levels. In addition, oxidative stress biomarkers (MDA and NO) were increased in AP with decreased antioxidant SOD activity and GSH level. Moreover, HO-1 immunostaining was increased in the AP group. Cilostazol pretreatment reversed the histopathological change; decreased the amylase activity and the levels of TNF-α, VCAM-1, and MPO; and increased the levels of insulin, adiponectin, cGMP, cAMP, and IL-10. Moreover, cilostazol decreased MDA and NO but increased SOD and GSH. Lastly, cilostazol increased the HO-1 immunostaining more than in the AP group. These data suggest that cilostazol protects against L-arginine-induced AP, which may be related to an increase in cGMP, cAMP, and upregulation of HO-1 with subsequent anti-inflammatory and antioxidant properties.

Research Progress on Alzheimer's Disease and Resveratrol

Alzheimer's disease (AD), a common irreversible neurodegenerative disease characterized by amyloid-β plaques, neurofibrillary tangles, and changes in tau phosphorylation, is accompanied by memory loss and symptoms of cognitive dysfunction. Increases in disease incidence due to the ageing of the population have placed a great burden on society. To date, the mechanism of AD and the identities of adequate drugs for AD prevention and treatment have eluded the medical community. It has been confirmed that phytochemicals have certain neuroprotective effects against AD. For example, some progress has been made in research on the use of resveratrol, a natural polyphenolic phytochemical, for the prevention and treatment of AD in recent years. Elucidation of the pathogenesis of AD will create a solid foundation for drug treatment. In addition, research on resveratrol, including its mechanism of action, the roles of signalling pathways and its therapeutic targets, will provide new ideas for AD treatment, which is of great significance. In this review, we discuss the possible relationships between AD and the following factors: synapses, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptors (AMPARs), silent information regulator 1 (SIRT1), and estrogens. We also discuss the findings of previous studies regarding these relationships in the context of AD treatment and further summarize research progress related to resveratrol treatment.

Overexpression of Nrf2 Protects Against Lipopolysaccharide and Cerulein-Induced Pancreatitis In Vitro and In Vivo

OBJECTIVES

In this study, we focused on the function of nuclear factor E2-related factor 2 (Nrf2) in acute pancreatitis (AP), which has been shown to have protective effects in gliomas, hepatocytes, and astrocytes.

METHODS

Acute pancreatitis cell line and animal model were induced by administration of lipopolysaccharide and cerulein into the cell supernatant or intraperitoneal injection. Oxidative stress status was evaluated by measuring the level of amylase, C-reactive protein, malondialdehyde, superoxide dismutase, and myeloperoxidase. Morphological alterations in the pancreas were evaluated by hematoxylin-eosin staining, the wet-to-dry weight ratio, and the pathology injury scores. Western blot, reverse transcription-polymerase chain reaction, and immunofluorescence staining were performed to analyze the expression of Nrf2, Heme oxygenase 1, and NAD(P)H: quinone oxidoreductase 1.

RESULTS

Overexpression of Nrf2 inhibits oxidative stress and inflammatory responses by inducting the expression of superoxide dismutase as well as reducing the level of amylase, malondialdehyde, and myeloperoxidase in the AR42J rat pancreatic acinar cells in AP. Importantly, overexpression of Nrf2 displayed the same protective effect in vivo. Data from an AP rat model showed that Nrf2 could relieve pancreatic damage.

CONCLUSIONS

These results indicated that Nrf2 has a protective role in lipopolysaccharide and cerulein-induced cytotoxicity, providing potential therapeutic strategies for the treatment of AP.

Association of Serum Levels of Silent Information Regulator 1 with Persistent Organ Failure in Acute Pancreatitis

BACKGROUND/AIMS

Early assessment is a key factor for adequate and comprehensive treatment of acute pancreatitis (AP). Silent information regulator 1 (SIRT1) plays an important role in inflammation. The aim was to explore the relationship between serum SIRT1 and persistent organ failure (POF) in patients with AP.

METHODS

Thirty-seven healthy controls (HCs) and 113 patients with AP were recruited for this study. All 113 patients whose blood samples were collected on the first morning after admission were within 48 h of the onset of AP symptoms. The concentration of serum SIRT1 protein was determined by enzyme-linked immunosorbent assay.

RESULTS

The serum SIRT1 protein levels were 1495.7 ± 185.9, 2098.3 ± 153.6, 2498.4 ± 198.2, and 3674.3 ± 170.8 pg/ml in the HCs, mild AP, moderately severe AP, and severe AP groups, respectively. Obvious differences were observed between HCs and patients with AP (P < 0.05). Significant increases were observed in SIRT1 concentrations in patients with POF compared with non-POF patients (P < 0.05). When the cut-off of the SIRT1 concentration was 4065.4 pg/ml, the serum SIRT1 concentration had an area under the curve (AUC) of the receiver operating characteristic curve of 0.825 (95% CI 0.744-0.906) for predicting POF, with a sensitivity of 61.4% and specificity of 92.8%. Combining serum SIRT1 and bedside index for severity acute pancreatitis (BISAP) achieved 0.931 (95% CI 0.882, 0.980) of AUC for the predication of POF.

CONCLUSIONS

High serum SIRT1 levels may serve as an early predictive marker for POF. Combining the serum SIRT1 concentration with BISAP increased the ability to predict outcomes.

Effects of combined therapy with resveratrol, continuous and interval exercises on apoptosis, oxidative stress, and inflammatory biomarkers in the liver of old rats with non-alcoholic fatty liver disease

CONTEXT

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disorder.

OBJECTIVE

Effects of combined therapy with resveratrol, interval and continuous exercises on oxidative stress, inflammation, and apoptosis in the liver of rats with NAFLD.

METHODS

NAFLD rats were organised in patient, saline, resveratrol (RSV), continuous exercise, interval exercise, continuous exercise + RSV, and interval exercise + RSV groups.

RESULTS

Resveratrol supplementation alone or in combination with interval and continuous training significantly decreased malondialdehyde and TNF-α level (p < .05), while the levels of catalase; superoxide dismutase and IL-10 were significantly increased (p < .05). Although RSV alone significantly decreased the percentage of apoptotic cells (17.12%), its combination with interval (10.74%), and continuous (14.85%) exercise training demonstrated higher anti-apoptotic activity (p < .05).

CONCLUSIONS

Although resveratrol alone has an antioxidant, anti-apoptotic and anti-inflammatory properties, combined therapy with interval, and continuous training can be more effective to mitigate these abnormalities in NAFLD patients.

VEGF-A promotes angiogenesis after acute myocardial infarction through increasing ROS production and enhancing ER stress-mediated autophagy

Proangiogenesis is generally regarded as an effective approach for treating ischemic heart disease. Vascular endothelial growth factor (VEGF)-A is a strong and essential proangiogenic factor. Reactive oxygen species (ROS), endoplasmic reticulum (ER) stress, and autophagy are implicated in the process of angiogenesis. This study is designed to clarify the regulatory mechanisms underlying VEGF-A, ROS, ER stress, autophagy, and angiogenesis in acute myocardial infarction (AMI). A mouse model of AMI was successfully established by occluding the left anterior descending coronary artery. Compared with the sham-operated mice, the microvessel density, VEGF-A content, ROS production, expression of vascular endothelial cadherin, positive expression of 78 kDa glucose-regulated protein/binding immunoglobulin protein (GRP78/Bip), and LC3 puncta in CD31-positive endothelial cells of the ischemic myocardium were overtly elevated. Moreover, VEGF-A exposure predominantly increased the expression of beclin-1, autophagy-related gene (ATG) 4, ATG5, inositol-requiring enzyme-1 (IRE-1), GRP78/Bip, and LC3-II/LC3-I as well as ROS production in the human umbilical vein endothelial cells (HUVECs) in a dose and time-dependent manner. Both beclin-1 small interfering RNA and 3-methyladenine treatment predominantly mitigated VEGF-A-induced tube formation and migration of HUVECs, but they failed to elicit any notable effect on VEGF-A-increased expression of GRP78/Bip. Tauroursodeoxycholic acid not only obviously abolished VEGF-A-induced increase of IRE-1, GRP78/Bip, beclin-1 expression, and LC3-II/LC3-I, but also negated VEGF-A-induced tube formation and migration of HUVECs. Furthermore, N-acetyl- l-cysteine markedly abrogated VEGF-A-increased ROS production, IRE-1, GRP78/Bip, beclin-1 expression, and LC3-II/LC3-I in the HUVECs. Taken together, our data demonstrated that increased spontaneous production of VEGF-A may induce angiogenesis after AMI through initiating ROS-ER stress-autophagy axis in the vascular endothelial cells.

SRT1720 ameliorates sodium taurocholate-induced severe acute pancreatitis in rats by suppressing NF-κB signalling

Severe acute pancreatitis (SAP) is a medical emergency that is often associated with multiple organ failure and high mortality. Although an SAP diagnosis requires prompt treatment, therapeutic options remain limited. SRT1720 is a newly formulatedSIRT1 activator that exerts multiple pharmacological activities with beneficial health effects. However, its potential as an SAP treatment has not been explored. The current study assessed the effect of SRT1720 on a rat model of sodium taurocholate-induced SAP and explored the underlying mechanism. SAP was induced in rats by retrograde injection of a 3.5% sodium taurocholate solution (1 ml/kg) in the biliopancreatic duct. SRT1720 (5 mg/kg) was administered intraperitoneally after sodium taurocholate exposure. Serum samples were analysed for inflammatory cytokine levels and select enzymatic activities using the enzyme-linked immunosorbent assay and commercial enzyme activity assay kits, respectively; protein expression levels were evaluated by western blotting; mRNA levels of biomarkers were determined by quantitative real-time PCR; histopathological changes were analysed by haematoxylin and eosin staining and immunohistochemistry.SRT1720 treatment significantly reduced serum amylase, lipase, pancreatic histological scores, proinflammatory cytokine (TNF-α and IL-6) levels, and expression of NF-κB and p65 in sodium taurocholate-induced SAP rats. Importantly, the treatment stimulated SIRT1 and IκBα levels in pancreatic tissue. Our data suggest that SRT1720 protects rats from sodium taurocholate-induced SAP by suppressing the NF-κB signalling pathway.

Isoliquiritigenin Ameliorates Acute Pancreatitis in Mice via Inhibition of Oxidative Stress and Modulation of the Nrf2/HO-1 Pathway

Oxidative stress plays a crucial role in the pathogenesis of acute pancreatitis (AP). Isoliquiritigenin (ISL) is a flavonoid monomer with confirmed antioxidant activity. However, the specific effects of ISL on AP have not been determined. In this study, we aimed to investigate the protective effect of ISL on AP using two mouse models. In the caerulein-induced mild acute pancreatitis (MAP) model, dynamic changes in oxidative stress injury of the pancreatic tissue were observed after AP onset. We found that ISL administration reduced serum amylase and lipase levels and alleviated the histopathological manifestations of pancreatic tissue in a dose-dependent manner. Meanwhile, ISL decreased the oxidative stress injury and increased the protein expression of the Nrf2/HO-1 pathway. In addition, after administering a Nrf2 inhibitor (ML385) or HO-1 inhibitor (zinc protoporphyrin) to block the Nrf2/HO-1 pathway, we failed to observe the protective effects of ISL on AP in mice. Furthermore, we found that ISL mitigated the severity of pancreatic tissue injury and pancreatitis-associated lung injury in a severe acute pancreatitis model induced by L-arginine. Taken together, our data for the first time confirmed the protective effects of ISL on AP in mice via inhibition of oxidative stress and modulation of the Nrf2/HO-1 pathway.

Activation of Sirtuin 1 Attenuates High Glucose-Induced Neuronal Apoptosis by Deacetylating p53

Diabetes mellitus (DM) has been proven to be a key risk factor for cognitive impairment. Previous studies have implicated hippocampal neuronal apoptosis in diabetes-related cognitive impairment. However, the underlying mechanism remains unknown. Sirtuin 1 (SIRT1) is a protein deacetylase depended on nicotinamide adenine dinucleotide. Furthermore, it is indispensable in normal learning and memory. Whether SIRT1 is taken part in diabetes-induced neuronal apoptosis and thus involve in the development of diabetic cognitive impairment is still not clear. To address this issue, we examined the possible role of SIRT1 in hippocampal neuronal apoptosis in streptozotocin-induced diabetic mice. Furthermore, the possible mechanism was investigated in high glucose-induced SH-SY5Y cells. We found that downregulation of the activity and expression of SIRT1 was associated with increased hippocampal neuronal apoptosis in mice. In vitro, cell apoptosis induced by high glucose which was accompanied by a downregulation of SIRT1 and an increased acetylation of p53. On the contrary, activation of SIRT1 using its agonist resveratrol ameliorated cell apoptosis via deacetylating p53. Our data suggest that high concentration of glucose can induce neuronal apoptosis through downregulation of SIRT1 and increased acetylation of p53, which likely contribute to the development of cognitive impairment in diabetes.