BMSC-derived Exosomes Ameliorate Peritoneal Dialysis-associated Peritoneal Fibrosis via the Mir-27a-3p/TP53 Pathway

Objective:Peritoneal fibrosis(PF)is the main cause of declining efficiency and ultrafiltration failure of the peritoneum,which restricts the long-term application of peritoneal dialysis(PD).This study aimed to investigate the therapeutic effects and mechanisms of bone marrow mesenchymal stem cells-derived exosomes(BMSC-Exos)on PF in response to PD.Methods:Small RNA sequencing analysis of BMSC-Exos was performed by second-generation sequencing.C57BL/6J mice were infused with 4.25%glucose-based peritoneal dialysis fluid(PDF)for 6 consecutive weeks to establish a PF model.A total of 36 mice were randomly divided into 6 groups:control group,1.5%PDF group,2.5%PDF group,4.25%PDF group,BMSC-Exos treatment group,and BMSC-Exos+TP53 treatment group.Reverse transcription quantitative polymerase chain reaction(RT-qPCR)was performed to measure the expression level of miR-27a-3p in BMSC-Exos and peritoneum of mice treated with different concentrations of PDF.HE and Masson staining were performed to evaluate the extent of PF.The therapeutic potential of BMSC-Exos for PF was examined through pathological examination,RT-qPCR,Western blotting,and peritoneal function analyses.Epithelial-mesenchymal transition(EMT)of HMrSV5 was induced with 4.25%PDF.Cells were divided into control group,4.25%PDF group,BMSC-Exos treatment group,and BMSC-Exos+TP53 treatment group.Cell Counting Kit-8 assay was used to measure cell viability,and transwell migration assay was used to verify the capacity of BMSC-Exos to inhibit EMT in HMrSV5 cells.Results:Small RNA sequencing analysis showed that miR-27a-3p was highly expressed in BMSC-derived exosomes compared to BMSCs.The RT-qPCR results showed that the expression of miR-27a-3p was upregulated in BMSC-Exos,but decreased in PD mice.We found that PF was glucose concentration-dependently enhanced in the peritoneum of the PD mice.Compared with the control mice,the PD mice showed high solute transport and decreased ultrafiltration volume as well as an obvious fibroproliferative response,with markedly increased peritoneal thickness and higher expression ofα-SMA,collagen-I,fibronectin,and ECM1.The mice with PD showed decreased miR-27a-3p.Peritoneal structural and functional damage was significantly attenuated after BMSC-Exos treatment,while PF and mesothelial damage were significantly ameliorated.Additionally,markers of fibrosis(α-SMA,collagen-I,fibronectin,ECM1)and profibrotic cytokines(TGF-β1,PDGF)were downregulated at the mRNA and protein levels after BMSC-Exos treatment.In HMrSV5 cells,BMSC-Exos reversed the decrease in cell viability and the increase in cell migratory capacity caused by high-glucose PDF.Western blotting and RT-qPCR analysis revealed that BMSC-Exos treatment resulted in increased expression of E-cadherin(epithelial marker)and decreased expression ofα-SMA,Snail,and vimentin(mesenchymal markers)compared to those of the 4.25%PDF-treated cells.Importantly,a dual-luciferase reporter assay showed that TP53 was a target gene of miR-27a-3p.TP53 overexpression significantly reversed the decreases in PF and EMT progression induced by BMSC-Exos.Conclusion:The present results demonstrate that BMSC-Exos showed an obvious protective effect on PD-related PF and suggest that BMSC-derived exosomal miR-27a-3p may exert its inhibitory effect on PF and EMT progression by targeting TP53.

The mechanism of Astragalus membranaceus in treating peritoneal fibrosis by intervening the key syndrome and pathology based on Q-marker theory

Objective:To evaluate the mechanism of Astragalus membranaceus(AM)by intervening peritoneal mesothelial cells(PMCs),epithelial-mesenchymal transition(EMT),and spleen deficiency syndrome(SDS)in peritoneal fibrosis(PF),we base on employing the strategy of Q-marker theory combination network pharmacology method.Methods:First,we obtained the Q-markers of AM by searching the relevant literature and its pharmacological information was collected based on SwissADME.The SwissTargetPrediction and pharmmaper were employed to predict its potential target.Secondly,GeneCards,DisGeNET,and OMIM databases were employed to search the related targets of EMT,SDS,and PF.VENNY2.1 tool was employed to obtain the intersection targets of AM and the three;then the“AM potential target-SDS-EMT-PF”Venn diagram was constructed.The common targets of AM,EMT and SDS were uploaded to the STRING database and obtained the PPI protein interaction network map.Cytoscape 3.7.2 was employed to evaluate the core target of PPI network.PATHER and Metascape databases were used to analyze protein type,GO biological process,and KEGG pathway.Finally,a network diagram of the“TCM-component-disease target-pathway”was drawn.Results:A total of 10 AM Q-makers were screened out,corresponding to 335 targets of AM,2,728 targets of SDS,373 of EMT,and 612 PF targets were found.Among them,there are 155 common AM targets related to SDS and EMT.Key targets such as ALB,AKT1,VEGFA,TNF,EGFR,CASP3,SRC,STAT3,HSP90AA1,and ESR1 were obtained.The core drug include quercetin,astragalosideIII,Calycosin-7-O-beta-D-glucoside,astragalosideIV,etc.The types of PPI proteins include protein modification enzymes,metabolite transferases,transmembrane signal receptors,etc.Biological processes include the regulation of kinase activity,the positive regulation of transferase activity,and the regulation of kinase activity.The key pathways may include PI3K-Akt signaling pathways,the non-smad pathway of the TGF-βsignaling pathway,and the AGE-RAGE signaling pathway.Conclusion:AM could prevent and treat PF through a multi-component multi-target-multi-path mechanism.Astragalus saponins may be the main component types of AM intervening EMT pathology by strengthening the spleen and nourishing Qi.AstragalosideIV and astragalosideIII may be the constituents that can invigorate the spleen and replenish Qi.The results of this study contribute to a more comprehensive understanding of the critical components and mechanisms of AM by intervening SDS and EMT in the treatment of PF.

Melatonin decreases GSDME mediated mesothelial cell pyroptosis and prevents peritoneal fibrosis and ultrafiltration failure

Peritoneal fibrosis together with increased capillaries is the primary cause of peritoneal dialysis failure.Mesothelial cell loss is an initiating event for peritoneal fibrosis.We find that the elevated glucose concentrations in peritoneal dialysate drive mesothelial cell pyroptosis in a manner dependent on caspase-3 and Gasdermin E,driving downstream inflammatory responses,including the activation of macrophages.Moreover,pyroptosis is associated with elevated vascular endothelial growth factor A and C,two key factors in vascular angiogenesis and lymphatic vessel formation.GSDME deficiency mice are protected from high glucose induced peritoneal fibrosis and ultrafiltration failure.Application of melatonin abrogates mesothelial cell pyroptosis through a MT1R-mediated action,and successfully reduces peritoneal fibrosis and angiogenesis in an animal model while preserving dialysis efficacy.Mechanistically,melatonin treatment maintains mitochondrial integrity in mesothelial cells,meanwhile activating m TOR signaling through an increase in the glycolysis product dihydroxyacetone phosphate.These effects together with quenching free radicals by melatonin help mesothelial cells maintain a relatively stable internal environment in the face of high-glucose stress.Thus,Melatonin treatment holds some promise in preserving mesothelium integrity and in decreasing angiogenesis to protect peritoneum function in patients undergoing peritoneal dialysis.

Strategies for preventing peritoneal fibrosis in peritoneal dialysis patients： new insights based on peritoneal inflammation and angiogenesis

Peritoneal dialysis （PD） is an established form of renal replacement therapy. Long-term PD leads to morphologic and functional changes to the peritoneal membrane （PM）, which is defined as peritoneal fibrosis, a known cause of loss of peritoneal ultrafiltration capacity. Inflammation and angiogenesis are key events during the pathogenesis of peritoneal fibrosis. This review discusses the pathophysiology of peritoneal fibrosis and recent research progress on key fibrogenic molecular mechanisms in peritoneal inflammation and angiogenesis, including Toll-like receptor ligand-mediated, NOD-like receptor protein 3/interleukin-lp, vascular endothelial growth factor, and angiopoietin-2/Tie2 signaling pathways. Furthermore, novel strategies targeting peritoneal inflammation and angiogenesis to preserve the PM are discussed in depth.

Targeting cannabinoid signaling for peritoneal dialysisinduced oxidative stress and fibrosis

Long-term exposure to bioincompatible peritoneal dialysis(PD) solutions frequently results in peritoneal fibrosis and ultrafiltration failure,which limits the life-long use of and leads to the cessation of PD therapy.Therefore,it is important to elucidate the pathogenesis of peritoneal fibrosis in order to design therapeutic strategies to prevent its occurrence.Peritoneal fibrosis is associated with a chronic inflammatory status as well as an elevated oxidative stress(OS) status.Beyond uremia per se,OS also results from chronic exposure to high glucose load,glucose degradation products,advanced glycation end products,and hypertonic stress.Therapy targeting the cannabinoid(CB) signaling pathway has been reported in several chronic inflammatory diseases with elevated OS.We recently reported that the intra-peritoneal administration of CB receptor ligands,including CB_1 receptor antagonistsand CB_2 receptor agonists,ameliorated dialysis-related peritoneal fibrosis.As targeting the CB signaling pathway has been reported to be beneficial in attenuating the processes of several chronic inflammatory diseases,we reviewed the interaction among the cannabinoid system,inflammation,and OS,through which clinicians ultimately aim to prolong the peritoneal survival of PD patients.

Gene delivery in peritoneal dialysis related peritoneal fibrosis research

Objective To summarize the development of gene delivery vectors in peritoneal fibrosis research and discuss the feasibility and superiority of lentiviral vectors. Data sources The data in this article were collected from PubMed database with relevant English articles published from 1995 to 2011. Study selection Articles regarding the gene therapy in peritoneal fibrosis research using non-viral vectors, adenoviral vectors, retroviral vectors, and lentiviral vectors were selected. Data were mainly extracted from 60 articles, which are listed in the reference section of this review. Results Non-viral vector-mediated gene delivery （including naked DNA for ex vivo, oligonucleotides, ultrasound- contrast agent mediated naked gene delivery, etc.） and viral vector-mediated gene delivery （including adenovirus, helper-dependant adenovirus, and retrovirus vectors） have been successfully applied both in the mechanistic investigation and the potential prevention and treatment of peritoneal fibrosis. Conclusions Peritoneal fibrosis is a major complication of peritoneal dialysis （PD）. Recently, the wide use of the gene delivery technique made it possible to access and further research peritoneal fibrosis. The use of lentiviral vector is expected to be widely used in PD research in the future due to its advantages in gene delivery.

Abdominal cocoon syndrome-a rare culprit behind small bowel ischemia and obstruction:Three case reports

BACKGROUND Abdominal cocoon syndrome(ACS)represents a category within sclerosing encapsulating peritonitis,characterized by the encapsulation of internal organs with a fibrous,cocoon-like membrane of unknown origin,resulting in bowel obstruction and ischemia.Diagnosing this condition before surgery poses a cha-llenge,often requiring confirmation during laparotomy.In this context,we depict three instances of ACS:One linked to intestinal obstruction,the second exclu-sively manifesting as intestinal ischemia without any obstruction,and the final case involving a discrepancy between the radiologist and the surgeon.CASE SUMMARY Three male patients,aged 53,58,and 61 originating from Northern Thailand,arrived at our medical facility complaining of abdominal pain without any prior surgeries.Their vital signs remained stable during the assessment.The diagnosis of abdominal cocoon was confirmed through abdominal computed tomography(CT)before surgery.In the first case,the CT scan revealed capsules around the small bowel loops,showing no enhancement,along with mesenteric congestion affecting both small and large bowel loops,without a clear obstruction.The second case showed intestinal obstruction due to an encapsulated capsule on the CT scan.In the final case,a patient presented with recurring abdominal pain.Initially,the radiologist suspected enteritis as the cause after the CT scan.However,a detailed review led the surgeon to suspect encapsulating peritoneal sclerosis(ACS)and subsequently perform surgery.The surgical procedure involved complete removal of the encapsulating structure,resection of a portion of the small bowel,and end-to-end anastomosis.No complications occurred during surgery,and the patients had a smooth recovery after surgery,eventually discharged in good health.The histopathological examination of the fibrous membrane(cocoon)across all cases consistently revealed the presence of fibro-collagenous tissue,without any indications of malignancy.CONCLUSION Individuals diagnosed with abdominal cocoons commonly manifest vague symptoms of abdominal discomfort.An elevated degree of clinical suspicion,combined with the application of appropriate radiological evaluations,markedly improves the probability of identifying the abdominal cocoon before surgical intervention.In cases of complete bowel obstruction or ischemia,the established norm is the comprehensive removal of the peritoneal sac as part of standard care.Resection with intestinal anastomosis is advised solely when ischemia and gangrene have been confirmed.

Blocking Posttranslational Core Fucosylation Ameliorates Rat Peritoneal Mesothelial Cell Epithelial-Mesenchymal Transition

Background：Core fucosylation （CF）,catalyzed by α-1,6 fucosyltransferase （Fut8） in mammals,plays an important role in pathological processes through posttranslational modification of key signaling receptor proteins,including transforming growth factor （TGF）-β receptors and platelet-derived growth factor （PDGF） receptors.However,its effect on peritoneal fibrosis is unknown.Here,we investigated its influence on epithelial-mesenchymal transition （EMT） of rat peritoneal mesothelial cells （PMCs） in vitro induced by a high-glucose （HG） culture solution.Methods：Rat PMCs were first cultured in a HG （2.5%） culture solution to observe the CF expression level （fluorescein isothiocyanate-lens culinaris agglutinin）,we next established a knockdown model of rat PMCs in vitro with Fut8 small interfering RNA （siRNA） to observe whether inhibiting CF decreases the messenger RNA （mRNA） expression and protein expression of Fut8 and reverses EMT status.Rat PMCs were randomly divided into control group,mock group （transfected with scrambled siRNA）,Fut8 siRNA group,HG group,HG ＋ mock group,and HG ＋ Fut8 siRNA group.Finally,we examined the activation of TGF-β/Smad2/3 signaling and PDGF/extracellular signal-regulated kinase （ERK） signaling to observe the influence of CF on them.Results：CF,Fut8 mRNA,and protein expression were all significantly upregulated in HG-induced EMT model than those in the control rat PMCs （P 〈 0.05）.Fut8 siRNA successfully blocked CF of TGF-β receptors and PDGF receptors and attenuated the EMT status （E-cadherin and α-SMA and phenotypic changes） in HG-induced rat PMCs.In TGF-β/Smad2/3 signaling,Fut8 siRNA did not suppress the protein expression of TGF-3 receptors and Smad2/3;however,it significantly suppressed the phosphowlation of Smad2/3 （relative expression folds of HG ＋ Fut8 group vs.HG group：7.6 ± 0.4 vs.15.1 ± 0.6,respectively,P 〈 0.05）.In PDGF/ERK signaling,Fut8 siRNA did not suppress the protein expression of PDGF receptors and ERK,but it significantly suppressed the phosphorylation of ERK （relative expression folds of HG ＋ Fut8 group vs.HG group：8.7 ± 0.9 vs.15.6 ± 1.2,respectively,P 〈 0.05）.Blocking CF inactivated the activities of TGF-β and PDGF signaling pathways,and subsequently blocked EMT.Conclusions：These results demonstrate that CF contributes to rat PMC EMT.and that blocking it attenuates EMT.CF regulation is a potential therapeutic target of peritoneal fibrosis.