Analysis of m6A-regulated genes and subtype classification in lupus nephritis.

BACKGROUND: Lupus nephritis (LN) is the most common and severe clinical manifestation of systemic lupus erythematosus (SLE). N6-methyladenosine (m6A) is a reversible RNA modification and has been implicated in various biological processes. However, the roles of m6A regulators in LN are not fully demonstrated. METHODS: We downloaded the kidney tissue transcriptome dataset of LN patients and normal controls from the GEO database and extracted the expression levels of m6A regulators. We constructed and compared Random Forest (RF) and Support Vector Machine (SVM) models, and subsequently selected featured genes to develop nomogram models. The m6A subtypes were identified based on significantly differentially expressed m6A regulators, and the m6A gene subtypes were identified based on m6A-associated differential genes, and the two m6A modification patterns were comprehensively evaluated. RESULTS: We obtained the GSE32591 and GSE112943 datasets from the GEO database, including 78 LN samples and 36 normal control samples. We extracted the expression levels of 20 m6A regulators. By RF analysis we identified 7 characteristic m6A regulators and constructed nomogramh models with these 7 genes. We identified two m6A subtypes based on these seven important m6A regulators, and the immune cell infiltration levels of the two subtype clusters were significantly different. We identified two more m6A gene subtypes based on m6A-associated DEGs. We calculated the m6A scores using the principal component analysis (PCA) algorithm and found that the m6A scores of m6A cluster A and gene cluster A were lower than those of m6A cluster B and gene cluster B. In addition, we found that the levels of inflammatory factors were also significantly different between m6A clusters and gene clusters. CONCLUSION: This study confirms that m6A regulators are involved in the LN process through different modes of action and provide new diagnostic and therapeutic targets for LN.

An EM-Tracked Approach for Calibrating the 3D Pose of Flexible Endoscopes.

Flexible endoscopes are ideal instruments for visualizing and diagnosing the inner surfaces of organs via a minimally invasive incision. Calibrating a flexible endoscope is a troublesome yet inevitable process in image-based tools tracking. Aiming to simplify the calibration process, we propose an electromagnetic (EM)-tracked calibration approach that does not require any predefined poses of the EM sensor. A three-stage calibration protocol was presented in an extensor. First, the orientation of the endoscope tube was derived by conducting a circular rotation of the endoscope around its axis utilizing a pair of tightly bearing stands. Second, the 3D position of the endoscope tip was acquired by having the tip come into contact with a flat plane. Third, the pose model of the bending section was derived and transformed into the local coordinate system of the EM sensor attached to the endoscope handle. To assess the accuracy of the proposed calibration approach, two experiments were designed and performed. Experimental results indicate accuracies of 0.09 ± 0.06 deg and 0.03 ± 0.19 deg in the estimation of the endoscope tube orientation and 0.52 ± 0.29, 0.33 ± 0.11, and 0.29 ± 0.17 mm in the x, y, and z estimations of the endoscope tip position, respectively. The proposed approach is accurate and easy to operate, does not require the employment of custom calibration markers, and can be used not only in surgical training systems but also in the endoscopic-based tools tracking.

Effect of Youthful Blood Environment and Its Key Stem Cell Factor on Renal Interstitial Fibrosis in Elderly Mice.

INTRODUCTION: Youthful blood environment was shown to decelerate the aging process of the kidney and to attenuate senile renal fibrosis in a young-old parabiotic animal model; in addition, we identified a stem cell factor (SCF) that is closely linked with the process. This research was to investigate the effect of youthful blood environment on senile renal interstitial fibrosis and the role of SCF. METHODS: We bred SCF receptor c-Kit gene loss-of-function Wps/Wps mice and established a combination mice model that was subjected to unilateral ureteral obstructive (UUO) and parabiotic surgeries. Parabiotic mice were divided into isochronic parabiotic (young-young [Y-IP] and old-old [O-IP]) and heterochronic parabiotic (young-old [HP]) groups. UUO surgery was performed in one of the parabiotic pairs in the IP group (Y-IPuuo and O-IPuuo) and in the elderly mice in the HP group (O-HPuuo). In order to study the role of SCF/c-kit on renal interstitial fibrosis, UUO surgery was performed in wildtype (WT) and Wps/Wps mice. RESULTS: Fourteen days after UUO surgery, the kidney interstitial fibrosis area, kidney function, and the expressions of SCF/c-Kit, pNF-κB, and fibrosis-related proteins in the O-HPuuo group were significantly lower than those in the Ouuo and O-IPuuo groups. Compared with WT UUO mice, the expressions of pNF-κB and fibrosis-related proteins and the kidney function were all significantly decreased in Wps/Wps UUO mice. CONCLUSION: Youthful blood environment downregulated the expressions of SCF/c-Kit in elderly UUO mice and ameliorated UUO-induced kidney fibrosis and function loss.

Effect of Leptin Levels of Type 2 Diabetes Mellitus and Diabetic Complications.

PURPOSE: To investigate serum leptin levels in patients with type 2 diabetes mellitus (T2DM) and the relationship between leptin levels and T2DM complications and prevalence. METHODS: A total of 355 patients, 282 cases with T2DM and 73 normal controls, were recruited at 1st Medical Centre, Chinese PLA General Hospital (Beijing, China) between November 2013 and July 2014. Levels of serum leptin, biochemical markers and sexual hormones were measured, and clinical characteristics were retrieved through the electronic medical record system. RESULTS: Leptin levels in females were higher than that in males. Leptin levels in T2MD patients were positively correlated with body mass index, percent body fat, triglyceride, cystatin C homocysteine and salivary acid, and negatively correlated with glycosylated serum protein and glycosylated albumin levels. Leptin levels in males were positively correlated with systolic pressure and estradiol, and negatively correlated with testosterone and high density lipoprotein cholesterol. Sex (female) was positively correlated with the duration of disease. Leptin levels in T2DM patients with complications such as hypertension, diabetic nephropathy, diabetic peripheral neuropathy and coronary heart disease were higher than that in patients without such complications. Leptin levels in females with diabetic retinopathy and diabetic macroangiopathy were higher than that in patients without such complications, but there was no difference in males. CONCLUSIONS: Leptin has significant gender differences. Leptin levels are related to body mass index, percent body fat and sex hormone level in T2DM patients and may affect short-term blood glucose control in T2DM patients. Leptin levels are related to complications in patients with T2DM and affect the prevalence rates of complications.

A Novel Ferroptosis-Related lncRNA Signature for Prognosis Prediction in Patients with Papillary Renal Cell Carcinoma.

PURPOSE: Papillary renal cell carcinoma (PRCC) is a common renal cell carcinoma. Recent studies have reported that ferroptosis is involved in the occurrence and development of tumors. Long non-coding RNAs can be used as independent biomarkers for the diagnosis and prognosis of a variety of tumors. METHODS: Gene expression profile and clinical information of patients with PRCC were obtained from The Cancer Genome Atlas (TCGA) database. Lasso penalized Cox regression and univariate Cox regression analysis were utilized for model construction. The Kaplan-Meier (K-M) and receiver operating characteristic (ROC) curves were plotted to validate the predictive effect of the prognostic signature. Immune cell infiltration and immune function were compared between the high-risk and low-risk groups. Chemotherapy sensitivity analysis was also performed. RESULTS: We constructed a prognostic signature consisting of 15 ferroptosis-related lncRNAs. The K-M curves validated the fine predictive accuracy of the prognostic signature (p < 0.001). The area under the curve (AUC) of the lncRNA signature was 0.930, exhibiting robust prognostic capacity. The high-risk group had a greater degree of immune cell infiltration than the low-risk group. Significant differences in inflammation promotion, parainflammation, and type I IFN response were noted between the low-risk and high-risk groups (p < 0.01). The expression levels of immune checkpoints including CD80, IDO1, and LAG3 were significantly higher in the high-risk group than in the low-risk group (p < 0.05). Chemotherapy sensitivity analysis showed that MNX1-AS1, ZFAS1, MIR4435-2HG, and ADAMTS9-AS1 were significantly correlated with the sensitivity of some chemotherapy drugs (p < 0.05). CONCLUSION: We demonstrated that a ferroptosis-related lncRNA prognostic signature could be a novel biomarker for PRCC.

Exploring the Underlying Mechanism of Shenyankangfu Tablet in the Treatment of Glomerulonephritis Through Network Pharmacology, Machine Learning, Molecular Docking, and Experimental Validation.

PURPOSE: This study aimed to explore the underlying mechanisms of Shenyankangfu tablet (SYKFT) in the treatment of glomerulonephritis (GN) based on network pharmacology, machine learning, molecular docking, and experimental validation. METHODS: The active ingredients and potential targets of SYKFT were obtained through the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform, the targets of GN were obtained through GeneCards, etc. Perl and Cytoscape were used to construct an herb-active ingredient-target network. Then, the clusterProfiler package of R was used for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. We also used the STRING platform and Cytoscape to construct a protein-protein interaction (PPI) network, as well as the SwissTargetPrediction server to predict the target protein of the core active ingredient based on machine-learning model. Molecular-docking analysis was further performed using AutoDock Vina and Pymol. Finally, we verified the effect of SYKFT on GN in vivo. RESULTS: A total of 154 active ingredients and 255 targets in SYKFT were screened, and 135 targets were identified to be related to GN. GO enrichment analysis indicated that biological processes were primarily associated with oxidative stress and cell proliferation. KEGG pathway analysis showed that these targets were involved mostly in infection-related and GN-related pathways. PPI network analysis identified 13 core targets of SYKFT. Results of machine-learning model suggested that STAT3 and AKT1 may be the key target. Results of molecular docking suggested that the main active components of SYKFT can be combined with various target proteins. In vivo experiments confirmed that SYKFT may alleviate renal pathological injury by regulating core genes, thereby reducing urinary protein. CONCLUSION: This study demonstrated for the first time the multicomponent, multitarget, and multipathway characteristics of SYKFT for GN treatment.

A novel lncRNA-miRNA-mRNA competing endogenous RNA regulatory network in lung adenocarcinoma and kidney renal papillary cell carcinoma.

BACKGROUND: GPRIN1 may be a novel tumor regulator, but its role and mechanism in tumors are still unclear. METHODS: First, a pan-cancer correlation analysis was conducted on the expression and prognosis of GPRIN1 based on the data downloaded from The Cancer Genome Atlas (TCGA) database. Second, the Starbase database was used to predict the upstream miRNAs and lncRNAs of GPRIN1, and the expression analysis, survival analysis, and correlation analysis were performed to screen the microRNA (miRNAs)/long non-coding RNAs (lncRNAs) that had a correlation with kidney renal papillary cell carcinoma (KIRP) or lung adenocarcinoma (LUAD). Third, the CIBERSORT algorithm was employed to calculate the proportion of various types of immune cells, and then the R packages were used for evaluating the relation between GPRIN1 expression and tumor immune cell infiltration as well as between GPRIN1 and the immune cell biomarker. Finally, the correlation analysis was made on GPRIN1 and immune checkpoints (CD274, CTLA4, and PDCD1). RESULTS: The pan-cancer analysis suggested that GPRIN1 was up-expressed in KIRP and LUAD, and it correlated with poor prognosis. LINC00894/MMP25-AS1/SNHG1/LINC02298/MIR193BHG-miR-140-3p was likely to be the most promising upstream regulation pathway of GPRIN1. Upexpression of LINC00894/MMP25-AS1/SNHG1/LINC02298/MIR193BHG and downexpression of miR-140-3p were found relevant with poor outcomes of KIRP and LUAD. GPRIN1 expression was significantly correlated with tumor immune cell infiltration, immune cell biomarkers, and immune checkpoints. CONCLUSIONS: The competitive endogenous (ceRNA) of miR-140-3p-GPRIN1 axis and its upstream lncRNAs are closely related to KIRP and LUAD, and might affect the prognosis and therapeutic effect of KIRP and LUAD.

RIPK2 is an unfavorable prognosis marker and a potential therapeutic target in human kidney renal clear cell carcinoma.

Receptor Interacting Serine/Threonine Kinase 2 (RIPK2) is located on chromosome 8q21 and encodes a protein containing a C-terminal caspase activation and recruitment domain (CARD), which is a component of signaling complexes in both the innate and adaptive immune pathways. To estimate the value of RIPK2 in evaluating the prognosis and guiding the targeted therapy for patients with kidney renal clear cell carcinoma (KIRC), we analyzed total 526 KIRC samples from The Cancer Genome Atlas (TCGA) database. Our result showed that RIPK2 was upregulated in KIRC tumor samples compared with normal samples. Cox regression was performed to calculate the hazard ratio of RIPK2 expression as an unfavorable prognosis feature for overall survival. Moreover, RIPK2 expression was positively correlated to the high-risk clinical stage, and metastasis features. The upregulation of RIPK2 was strongly correlated with various immune signaling pathway dysregulations as well as immune phenotypes changes in KIRC patient's cohort. In addition, inhibition of RIPK2 activity by either shRNA-mediated knockdown or inhibitor significantly reduced kidney cancer cell viability, trans-migration in vitro, and impaired tumor growth in vivo. In conclusion, elevated RIPK2 expression indicates a worse prognosis for KIRC patients and could serve as a potential prognostic biomarker and therapeutic target in kidney cancer.

Tumor-preventing activity of aspirin in multiple cancers based on bioinformatic analyses.

BACKGROUND: Acetylsalicylic acid was renamed aspirin in 1899, and it has been widely used for its multiple biological actions. Because of the diversity of the cellular processes and diseases that aspirin reportedly affects and benefits, uncertainty remains regarding its mechanism in different biological systems. METHODS: The Drugbank and STITCH databases were used to find direct protein targets (DPTs) of aspirin. The Mentha database was used to analyze protein-protein interactions (PPIs) to find DPT-associated genes. DAVID was used for the GO and KEGG enrichment analyses. The cBio Cancer Genomics Portal database was used to mine genetic alterations and networks of aspirin-associated genes in cancer. RESULTS: Eighteen direct protein targets (DPT) and 961 DPT-associated genes were identified for aspirin. This enrichment analysis resulted in eight identified KEGG pathways that were associated with cancers. Analysis using the cBio portal indicated that aspirin might have effects on multiple tumor suppressors, such as TP53, PTEN, and RB1 and that TP53 might play a central role in aspirin-associated genes. DISCUSSION: The results not only suggest that aspirin might have anti-tumor actions against multiple cancers but could also provide new directions for further research on aspirin using a bioinformatics analysis approach.

Adjuvant pegylated interferon therapy improves the survival outcomes in patients with hepatitis-related hepatocellular carcinoma after curative treatment: A meta-analysis.

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most common cancers and the second leading cause of cancer-related deaths in men worldwide. Surgical resection of HCC remains the mainstay treatment procedure. As a result of hepatitis viral infection, the postoperative survival outcome in patients with HCC is not satisfactory. Recently, studies have reported that due to its treatment effect on hepatitis infection, pegylated interferon (Peg-IFN)-based therapy could improve the survival outcome after the treatment of hepatitis-related HCC. However, the postoperative effect of this regimen on the survival outcomes in patients with hepatitis-related HCC remains debatable. The present study conducted a meta-analysis to evaluate the effects of adjuvant Peg-IFN-based therapy on the survival outcomes in patients with hepatitis-related HCC after the curative treatment. METHODS: A systematic search was conducted to identify studies on the survival outcomes in patients with hepatitis-related HCC after a curative treatment with adjuvant Peg-IFN. PubMed, EmBase, and Cochrane Library databases were searched until September 20, 2017. The retrieved studies were independently assessed by 2 reviewers, to identify the potentially eligible studies and extract data of interest. STATA software (Version 10.0, STATA Corporation, College Station, Texas) software was used for all statistical analyses. RESULTS: The pooled results showed that adjuvant Peg-IFN-based therapy improved the 3- and 5-year recurrence-free survival (RFS) rates of patients with hepatitis-related HCC (3-year RFS, HR = 0.80; 95% CI: 0.64-0.99, P = .04; P = .81 for heterogeneity; 5-year RFS, HR = 0.82; 95% CI: 0.67-0.99, P = .04; P = .84 for heterogeneity). For the 5-year overall survival (OS) outcomes of Peg-IFN therapy for hepatitis-related HCC after the curative treatment, the pooled results showed a significant difference between the 2 groups (HR = 0.67; 95% CI: 0.47-0.97, P = .03; P = .99 for heterogeneity). CONCLUSIONS: Adjuvant Peg-IFN-based therapy could improve the RFS and OS outcomes in patients after curative treatment of hepatitis-related HCC, with no severe adverse effects.

Identification of proteins potentially associated with renal aging in rats.

We established a young (Y)-old (O) rat kidney transplantation model. With this model, we detected no age-related differences in renal structure between Y→Y and Y→O kidneys or O→O and O→Y kidneys. However, we did detect differences in levels of the senescence markers ß-gal and p16 as well as the inflammatory cytokines TNF-α and IL-1ß. Using proteomics analysis we detected 66 proteins associated with suppression of aging and 73 proteins associated with enhancement of aging. After construction of a protein-protein interaction network, a total of 73 nodes and 99 edges were analyzed using MCODE, and three significant modules were selected. GO and KEGG analyses showed that these proteins were mainly located in mitochondria and were largely related to oxidative stress. Among them, SOD1 expression was lower in Y→O than Y→Y kidneys and higher in O→Y than O→O kidneys. Acetylated (Ac)-NF-κB showed the opposite expression profile. In addition, SOD1 expression was higher in primary tubular epithelial cells from young rats than old rats, and SOD1 knockdown led to increased Ac-NF-κB expression. These findings suggest the local renal environment, particularly oxidative stress/mitochondrial function, affects renal aging.

A Young Blood Environment Decreases Aging of Senile Mice Kidneys.

Whether changes in internal body environment affect kidney aging remains unclear. Specifically, it is unknown whether transplanted kidneys from older donors recover from tissue damage after placement in younger recipients. In this study, a parabiosis animal model was established to investigate the effects of a young internal body environment on aged kidneys. The animals were divided into six groups: young (Ycon) and old control (Ocon) groups, isochronic youth-youth group (Y-IP), elderly-elderly group (O-IP), and heterochronic youth (Y-HP) and elderly (O-HP) groups. After parabiosis, tubule and interstitial tissue scores in the O-HP group were significantly lower than in the Ocon and O-IP groups. The expression of aging-related protein p16 and SA-ß-gal in the O-HP group was significantly reduced compared with the Ocon and O-IP groups. Autophagy factors Atg5 and LC3BII were significantly upregulated, whereas the expression of the autophagic degradation marker (P62) was significantly downregulated in the O-HP group compared with the Ocon and O-IP groups. With the same comparison, the positive cells of TUNEL staining and the expression of IL-6 and IL-1ß were significantly reduced, whereas the total/cleaved caspase-3 and total/pNF-κB were significantly increased in the O-HP group. The results demonstrated that a young blood environment significantly reduces kidney aging. These findings provide new evidence supporting an increase in the upper age limit for human kidney transplantation donors.

Association between microRNA polymorphisms and the risk of inflammatory bowel disease.

Common single nucleotide polymorphisms (SNPs) in precursor microRNAs may change their properties via altering the expression of miRNAs, resulting in diverse functional consequences. The present study evaluated the effects of four common SNPs in pro-miRNAs on the risk of inflammatory bowel disease (IBD) and IBD­associated colorectal cancer (IBD-CRC). In a hospital based case­control investigation in a Chinese population, 468 patients with IBD and 450 age- and gender-matched healthy subjects were enrolled in the present study. The SNPs were genotyped using a polymerase chain reaction (PCR)-restriction fragment length polymorphism technique. The expression levels of the miRNAs were detected by reverse transcription­PCR. For rs2910164, the risk of IBD was significantly increased in the GC and CC genotypes. The mean expression levels of mir­146a in the CC and GC genotypes were lower, compared with that of the GG genotype. For rs2292832, an increased risk of IBD was detected in the recessive model of the TT genotype, compared with the combination of the CT and CC genotypes. The [T] allele was found to be at increased significantly, with a 1.268­fold increased risk of IBD, compared with the [C] allele. The mean expression levele of mir­149 expression level in the TT genotype was lower, compared with that of the CC genotype. For rs11614913, the risk of IBD­CRC was significantly increased in the CC genotype, compared with the TT genotype. In the dominant model, the CC genotype had a high risk of IBD­CRC, compared with the combination of the CT and TT genotypes. These findings suggested that mir-146a rs2910164 and mir­149 rs2292832 may be associated with the increased risk of IBD via alterations in the expression levels of miRNAs. Therefore, mir­196a rs11614913 may contribute to the progression of IBD-CRC.

[Mesenchymal stem cells attenuate acute kidney injury via regulation of natural immune system].

Objective: To explore the potential mechanisms of mesenchymal stem cell (MSC) therapy in ischemia/reperfusion injury (IRI)-induced acute kidney injury (AKI). Methods: Forty-five C57/BL6 male mice were randomly divided into three groups: sham group, IRI group, and IRI+MSCs group, with 15 mice in each group. The IRI-induced AKI model in mice was reproduced by clamping both renal pedicles for 35 minutes. In the sham group, both kidneys were exposed, but their pedicles were not clamped. Six hours after reperfusion, mice in IRI+MSCs group received 100 µL of MSCs (1×104 /µL) isolated from the bone marrow from C57/BL6 mice via tail vein, while the mice in the IRI group received same amount of normal saline. Blood samples were harvested at 48 hours after reperfusion, and levels of serum creatinine (SCr) and blood urea nitrogen (BUN) were determined. The changes in renal pathology were observed by microscopy with PAS staining, and the tubular injury and acute tubular necrosis (ATN) scores were calculated. The number of leukocytes (CD45+) infiltrated in kidney at 24 hours and 72 hours after reperfusion was measured with flow cytometry. The number of neutrophils (Ly-6G+) and macrophages (F4/80+) infiltrated in kidneys at 24 hours and 72 hours after reperfusion was determined by immunofluorescence. Results: There was significant increase in the related parameters in IRI group compared with those of sham group. The levels of SCr (µmol/L) and BUN (mmol/L) were 180.3±8.8 vs. 9.7±3.5, and 1 121.1±8.3 vs. 9.4±2.3, both P < 0.01. The score of tubular injury was 4.80±0.55 vs. 0 at 48 hours after reperfusion. The quantity of leukocyte (CD45+) infiltration in kidney at 24 hours and 72 hours after reperfusion was increased (×105 cells/g: 60.50±2.56 vs. 19.46±4.83, 42.00±1.87 vs. 14.70±3.74, both P < 0.01), and the number of neutrophils (Ly-6G+) and macrophages (F4/80+) infiltrated in kidney at 24 hours and 72 hours after reperfusion was also increase although the number of leukocytes infiltrated in kidney was significantly lower at 72 hours after reperfusion than that at 24 hours. There was significant lowering of the levels of SCr and BUN [SCr (µmol/L): 99.0±8.0 vs. 180.3±8.8, BUN (mmol/L): 84.5±7.6 vs. 112.1±8.3, both P < 0.01] in IRI+MSCs group, compared to IRI group. For the degree of tubular necrosis in two groups, the tubular injury scores were 2.60±0.55 vs. 4.80±0.55 (P < 0.05). The number of leukocytes infiltrated in kidney at 24 hours and 72 hours after reperfusion (×105 cells/g) were 24.20±4.53 vs. 60.50±2.56, 31.70±3.15 vs. 42.00±1.87 (both P < 0.01). The number of neutrophils was lowered despite (the number of macrophages was increased). However, the number of infiltrated leukocytes was significantly more in IRI+MSCs group at 72 hours than that at 24 hours (×105 cells/g: 31.70±3.15 vs. 24.20±4.53, P < 0.05). Conclusion: MSCs could protect against IRI induced AKI by reducing the total number of leuckocytes, especially that of the neutrophils infiltrating into ischemic kidney and by recruiting macrophages into ischemic kidney.

Differentially expressed microRNAs in bone marrow mesenchymal stem cell-derived microvesicles in young and older rats and their effect on tumor growth factor-ß1-mediated epithelial-mesenchymal transition in HK2 cells.

INTRODUCTION: The prevalence of renal fibrosis is higher in older than in younger individuals. Through paracrine activity, bone marrow mesenchymal stem cell-derived microvesicles (BM-MSC-MVs) influence the process of renal fibrosis. Differences in microRNA (miRNA) expression of BM-MSC-MVs that correlate with the age of the subjects and the correlation between miRNA expression and the process of renal fibrosis have not been established. The present study aimed to analyze differences in miRNA expression of BM-MSC-MVs between young or older rats and its influence on tumor growth factor-beta 1 (TGF-ß1)-mediated epithelial-mesenchymal transition (EMT) of HK2 cells to explore the causes of renal fibrosis in aged tissues. METHODS: miRCURY LNA Array (version 18.0) was used to identify differentially expressed miRNAs in BM-MSC-MVs of 3- and 24-month-old Fisher344 rats. Reverse transcription-polymerase chain reaction was used to verify miRNA levels in BM-MSC-MVs and in the serum of rats. A TGF-ß1-mediated EMT model was used to study the effects of BM-MSC-MVs and differentially expressed miRNAs on EMT. RESULTS: BM-MSCs from older rats showed more severe aging phenotypes compared with those of young rats. In addition, the growth rate and cell migration of BM-MSCs derived from older rats were significantly reduced. In secreted BM-MSC-MVs, the expression of miR-344a, miR-133b-3p, miR-294, miR-423-3p, and miR-872-3p was significantly downregulated in older rats than in younger rats (P < 0.05), and the serum level of these miRNAs exhibited the same patterns. Intervention using BM-MSC-MVs resulted in the weakening of TGF-ß1-mediated EMT in the aged rats. MiR-344a, miR-133b-3p, and miR-294 affected TGF-ß1-mediated EMT in HK2 cells. Among these, miR-133b-3p and miR-294 significantly inhibited TGF-ß1-mediated EMT in HK2 cells (P < 0.05). CONCLUSIONS: In older rats, the inhibitory effect of BM-MSC-MVs on TGF-ß1-mediated HK2 cell EMT was weaker than that observed in younger rats. In addition, miR-133b-3p and miR-294, which were downregulated in BM-MSC-MVs of older rats, remarkably inhibited TGF-ß1-mediated EMT in HK2 cells, suggesting that these may play a role in the fibrosis of aging renal tissues.

Mesenchymal stem cells ameliorate rhabdomyolysis-induced acute kidney injury via the activation of M2 macrophages.

INTRODUCTION: The mortality of rhabdomyolysis-induced acute kidney injury (AKI) is still high, as there is no effective therapy. It has been shown that bone marrow-derived mesenchymal stem cells (MSCs) can induce M2 macrophages, which mediate MSC protection in other experimental inflammation-related organ injury. This study was designed to investigate the protective effects of macrophage activation in MSC therapy of rhabdomyolysis-induced AKI. METHODS: MSCs were injected into glycerol-induced rhabdomyolysis mice. Renal injury was evaluated using the serum creatinine, urea nitrogen, renal pathology and acute tubular necrosis score. The distribution of MSCs was detected using two-photon fluorescence confocal imaging. Immunofluorescence of anti-F4/80 and anti-CD206 was performed to determine macrophages and M2 macrophages in the tissues of the kidney, and M2 macrophage infiltration was also evaluated using western blotting analyses. After depletion of macrophages using clodronate liposomes at the phase of kidney repair, renal injury was re-evaluated. RAW 264.7 macrophages were incubated with lipopolysaccharide and co-cultured with MSCs and subsequently visualised using immunofluorescence staining and flow cytometry analysis. Finally, disparate phenotype macrophages, including normal macrophages (M0), lipopolysaccharide-stimulated macrophages (M1), and MSC-co-cultured macrophages (M2), were infused into mice with AKI, which were pre-treated with liposomal clodronate. RESULTS: In vivo infusion of MSCs protected AKI mice from renal function impairment and severe tubular injury, which was accompanied by a time-dependent increase in CD206-positive M2 macrophage infiltration. In addition, depleting macrophages with clodronate delayed restoration of AKI. In vitro, macrophages co-cultured with MSCs acquired an anti-inflammatory M2 phenotype, which was characterised by an increased expression of CD206 and the secretory cytokine interleukin (IL)-10. The concentrations of IL-10, IL-6 and tumor necrosis factor α were evaluated using enzyme-linked immunosorbent assay. Furthermore, macrophage-depleted mice with intramuscular injection of glycerol were subjected to a single injection of different types of RAW 264.7 macrophages. Mice infused with M0 and M1 macrophages suffered a more severe histological and functional injury, while mice transfused with MSC-educated M2 macrophages showed reduced kidney injury. CONCLUSIONS: Our findings suggested that MSCs can ameliorate rhabdomyolysis-induced AKI via the activation of macrophages to a trophic M2 phenotype, which supports the transition from tubule injury to tubule repair.

Mesenchymal stem cells protect podocytes from apoptosis induced by high glucose via secretion of epithelial growth factor.

INTRODUCTION: The apoptosis and subsequent injury of podocytes plays a pathogenic role in diabetic nephropathy (DN). Mesenchymal stem cells (MSCs) are promising therapeutic cells for preventing apoptosis and reducing cellular injury. Our previous study found that MSCs could protect kidneys from diabetes-induced injury without obvious engraftment. So we evaluated the effects of human adipose-derived MSCs (hAd-MSCs) on podocytic apoptosis and injury induced by high glucose (HG) and the underlying mechanisms. METHODS: We used flow cytometry, Western blot and confocal fluorescence microscopy to study podocytic apoptosis and injury induced by HG at 24 hours, 48 hours, and 72 hours in the presence or absence of MSC-conditioned medium (CM). An antibody-based cytokine array was used to identify the mediating factor, which was verified by adding the neutralizing antibody (NtAb) to block its function or adding the recombinant cytokine to the medium to induce its function. RESULTS: hAd-MSC-CM reduced podocytic apoptosis in a dose-dependent manner, decreased the expression of podocytic cleaved caspase-3, and prevented the reduced expression and maintained the normal arrangement of podocytic synaptopodin and nephrin. However, human embryonic lung cell (Wi38)-CM failed to ameliorate podocytic apoptosis or injury. Twelve cytokines with concentration ratios (MSC-CM/Wi38-CM) >10-fold were identified. Epithelial growth factor (EGF) was singled out for its known ability to prevent apoptosis. Recombinant human EGF (rhEGF) prevented podocytic apoptosis and injury similarly to hAd-MSC-CM but, upon blockade of EGF, the beneficial effect of hAd-MSC-CM decreased dramatically. CONCLUSIONS: hAd-MSCs prevent podocytic apoptosis and injury induced by HG, mainly through secreting soluble EG.

Repeated systemic administration of human adipose-derived stem cells attenuates overt diabetic nephropathy in rats.

Adipose-derived stem cells (ASCs) can alleviate acute kidney injury and promote kidney cell regeneration and repair. To investigate the role of ASCs in diabetic nephropathy (DN), Sprague-Dawley rats were made diabetic by intraperitoneal injection of streptozotocin (STZ) after uninephrectomy. After 12 weeks, proteinuria was well established. Five times of 5×10(6) human ASCs repeatedly injected through a tail vein at 4 weekly intervals. A reduction in proteinuria was not observed in diabetic rats until 24 weeks. However, urinary protein excretion was significantly suppressed at 28 weeks and persisted up to 32 weeks after STZ treatment. ASC treatment significantly attenuated glomerulus hypertrophy and tubular interstitial injury, and led to the downregulation of WT-1 and synaptopodin expression. CFSE labeled ASCs were injected into DN rats via the tail vein. Within 24 h after injection, the cells were detected in lung, spleen, and peritubular regions, but rarely in pancreas. Human Alu gene expression was detected in lung and spleen up to 4 weeks after ASCs injection. ASC treatment did not improve hyperglycemia or pancreatic damage. In vitro, recombinant human glial cell line-derived neurotrophic factor (GDNF) prevented podocyte injury by high glucose similarly to ASC-conditioned medium. After blocking GDNF in ASC-CM with neutralizing antibody, the therapeutic effect of ASC-CM was significantly decreased. ASCs cocultured with podocytes restored the downregulation of synaptopodin expression, which was weakened by GDNF-RNA interfering. These findings indicate that repeated intravenous ASC can reduce diabetic kidney damage in rats even at the progressive stage, and promote podocyte recovery via GDNF secretion.

Novel mechanism for mesenchymal stem cells in attenuating peritoneal adhesion: accumulating in the lung and secreting tumor necrosis factor α-stimulating gene-6.

INTRODUCTION: We previously found that mesenchymal stem cells (MSCs) injected intravenously could attenuate peritoneal adhesion by secreting tumor necrosis alpha-stimulating gene (TSG)-6, while MSCs injected intraperitoneally could not. However, the underlying mechanism remains unclear. This study was designed to investigate the means by which MSCs exert their effects. METHODS: Rat bone marrow-derived MSCs/red fluorescent protein (RFP) were injected either intraperitoneally or intravenously into Sprague-Dawley (SD) rats at different time points after peritoneal scraping. Peritoneal adhesions were evaluated macroscopically at day 14 after scraping. The distribution of MSCs injected intraperitoneally or intravenously was traced by two-photon fluorescence confocal imaging and immunofluorescence microscopy. The co-localization of MSCs and macrophages in the lung and the spleen, and the expression of TSG-6 in MSCs trapped in the lung or the spleen were evaluated by immunofluorescence microscopy. The concentration of TSG-6 in serum was evaluated by ELISA. After intravenous injection of TSG-6- small interfering (si) RNA-MSCs, the expression of TSG-6 in MSCs and the concentration of TSG-6 in serum were reevaluated, and peritoneal adhesions were evaluated macroscopically and histologically. RESULTS: MSCs injected intraperitoneally failed to reduce peritoneal adhesion, and MSCs injected intravenously markedly improved peritoneal adhesion. Two-photon fluorescence confocal imaging showed that MSCs injected intravenously accumulated mainly in the lung, where they remained for seven days, and immunofluorescence microscopy showed few MSCs phagocytosed by macrophages. In contrast, large numbers of MSCs accumulated in the spleen with obvious phagocytosis by macrophages even at 4 hours after intraperitoneal injection. Immunofluorescence microscopy showed that MSCs that accumulated in the lung after intravenous injection could express TSG-6 within 12 hours, but TSG-6-siRNA-MSCs or MSCs accumulated in the spleen after intraperitoneal injection did not. ELISA showed that the concentration of TSG-6 in serum was increased at 4 hours after intravenous injection of MSCs, while there was no increase after injection of TSG-6-siRNA-MSCs or after intraperitoneal injection of MSCs. Moreover, intravenous injection of TSG-6-siRNA-MSCs failed to attenuate peritoneal adhesion. CONCLUSIONS: Our findings suggest that intravenously injected MSCs accumulated in the lung and attenuated peritoneal adhesion by secreting TSG-6, but intraperitoneally injected MSCs were phagocytosed by macrophages in the spleen and failed to attenuate peritoneal adhesion.

Mesenchymal stem cells attenuate peritoneal injury through secretion of TSG-6.

BACKGROUND: Mesothelial cell injury plays an important role in peritoneal fibrosis. Present clinical therapies aimed at alleviating peritoneal fibrosis have been largely inadequate. Mesenchymal stem cells (MSCs) are efficient for repairing injuries and reducing fibrosis. This study was designed to investigate the effects of MSCs on injured mesothelial cells and peritoneal fibrosis. METHODOLOGY/PRINCIPAL FINDINGS: Rat bone marrow-derived MSCs (5 × 10(6)) were injected into Sprague-Dawley (SD) rats via tail vein 24 h after peritoneal scraping. Distinct reductions in adhesion formation; infiltration of neutrophils, macrophage cells; number of fibroblasts; and level of transforming growth factor (TGF)-ß1 were found in MSCs-treated rats. The proliferation and repair of peritoneal mesothelial cells in MSCs-treated rats were stimulated. Mechanically injured mesothelial cells co-cultured with MSCs in transwells showed distinct increases in migration and proliferation. In vivo imaging showed that MSCs injected intravenously mainly accumulated in the lungs which persisted for at least seven days. No apparent MSCs were observed in the injured peritoneum even when MSCs were injected intraperitoneally. The injection of serum-starved MSCs-conditioned medium (CM) intravenously reduced adhesions similar to MSCs. Antibody based protein array of MSCs-CM showed that the releasing of TNFα-stimulating gene (TSG)-6 increased most dramatically. Promotion of mesothelial cell repair and reduction of peritoneal adhesion were produced by the administration of recombinant mouse (rm) TSG-6, and were weakened by TSG-6-RNA interfering. CONCLUSIONS/SIGNIFICANCE: Collectively, these results indicate that MSCs may attenuate peritoneal injury by repairing mesothelial cells, reducing inflammation and fibrosis. Rather than the engraftment, the secretion of TSG-6 by MSCs makes a major contribution to the therapeutic benefits of MSCs.