Induced pluripotent stem cell (iPS cell) holds great potential for applications in regenerative medicine, drug discovery, and disease modeling. We describe here a practical method to generate human iPS cells from urine-derived cells (UCs) under feeder-free, virus-free, serum-free condition and without oncogene c-MYC. We showed that this approach could be applied in a large population with different genetic backgrounds. UCs are easily accessible and exhibit high reprogramming efficiency, offering advantages over other cell types used for the purpose of iPS generation. Using the approach described in this study, we have generated 93 iPS cell lines from 20 donors with diverse genetic backgrounds. The non-viral iPS cell bank with these cell lines provides a valuable resource for iPS cells research, facilitating future applications of human iPS cells.

Rationale: Ischemia/reperfusion injury (IRI) is a major cause of acute kidney injury (AKI) that is associated with high morbidity and mortality, and for which specific treatments are lacking. In this study, we investigated the protective effect of human urine-derived stem cells (USCs) and their exosomes against IRI-induced AKI to explore the potential of these cells as a new therapeutic strategy. Methods: USCs were derived from fresh human urine. Cell surface marker expression was analyzed by flow cytometry to determine the characteristics of the stem cells. Adult male Sprague-Dawley rats were used to generate a lethal renal IRI model. One dose of USCs (2×10 6 cells/ml) or exosomes (20 µg/1 ml) in the experimental groups or saline (1 ml) in the control group was administered intravenously immediately after blood reperfusion. Blood was drawn every other day for measurement of serum creatinine (sCr) and blood urea nitrogen (BUN) levels. The kidneys were harvested for RNA and protein extraction to examine the levels of apoptosis and tubule injury. In vitro , the hypoxia-reoxygenation (H/R) model in human kidney cortex/proximal tubule cells (HK2) was used to analyze the protective ability of USC-derived exosomes (USC-Exo). Quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR), western blotting, superoxide dismutase activity, and malonaldehyde content analyses were used to evaluate oxidative stress in HK2 cells treated with USC-Exo after H/R. Exosomal microRNA sequencing techniques and bioinformatics analysis were used to search for enriched miRNAs in the exosomes and interacting genes. The interaction between miRNAs and the 3' untranslated region of the target gene was detected using a dual luciferase reporting system. The miRNA mimic and inhibitor were used to regulate the miRNA level in HK2 cells. Results: Treatment with USCs led to reductions in the levels of sCr, BUN, and renal tubular cell apoptosis; inhibited the infiltration of inflammatory cells; and protected renal function in the rat IRI model. Additionally, USC-derived exosomes protected against IRI-induced renal damage. miR-146a-5p was the most abundant miRNA in exosomes obtained from the conditioned medium (CM) of USCs. miR-146a-5p targeted and degraded the 3'UTR of interleukin-1 receptor-associated kinase 1 (IRAK1) mRNA, subsequently inhibited the activation of nuclear factor (NF)-κB signaling, and protected HK2 cells from H/R injury. USC transplantation also upregulated miR-146a-5p expression, downregulated IRAK1 expression and inhibited nuclear translocation of NF-κB p65 in the kidney of the rat IRI model. Conclusions: According to our experimental results, USCs could protect against renal IRI via exosomal miR-146a-5p , which could target the 3'UTR of I...

Objective: To evaluate the diagnostic performance of donor-derived plasma cell-free DNA (cfDNA) in discriminating antibody-mediated rejection (ABMR) or de novo donorspecific antibodies (DSA) without histological lesions in kidney allograft recipients. Methods:In this prospective single center observational study, we enrolled kidney allograft recipients between November, 2016 and September, 2017 at the First Affiliated Hospital of Sun Yat-sen University. Kidney allograft recipients with ABMR, de novo DSA but no histological lesions or negative DSA, and stable renal function were included. The plasma cfDNA fraction was measured using a targeted, single nucleotide polymorphism (SNP)-based assay. Pathological diagnosis was made according to the 2015 Banff Kidney Rejection Classification. The area under the ROC curve (AUC-ROC) was determined using the bootstrapping method to estimate median and 95% confidence interval (95% CI). The sensitivity, specificity and Youden index, positive predictive value (PPV), and negative predictive value (NPV) were calculated for specific cfDNA fractions.Results: Totally 37 consecutive patients received kidney allografts, including 18 recipients in the ABMR group and 19 recipients in the stable allograft group (7 DSApositive and 12 DSA-negative). All patients in the ABMR group were DSA positive and 7 patients in the stable group were DSA positive but had no pathologically proven ABMR. The median donor-derived plasma cfDNA fraction was 2.4% (Q1 1.52% -Q3 3.70%) in the ABMR group, and was significantly higher than that of the stable group (0.65%, Q1 Frontiers in Immunology | www.frontiersin.org February 2020 | Volume 11 | Article 342 Zhang et al.Donor-Derived cfDNA in Kidney ABMR 0.57% -Q3 0.97%; P < 0.001), but comparable with that of the DSA-positive patients in the stable allograft group (P = 0.074). The AUC-ROC of cfDNA was 0.90 (95% CI, 0.79-0.98). When a cfDNA threshold of 1% was chosen, it had a sensitivity of 88.9% and a specificity of 73.7%. The PPV was 76.2% and the NPV was 87.5%.Conclusion: Donor-derived plasma cfDNA fraction increased in kidney allograft recipients with ABMR. Detection of donor-derived plasma cfDNA fraction may contribute to the discrimination between ABMR and stable renal allograft function and may aid early recognition of earlier stage antibody-mediated injury.

The Meinwald rearrangement is a synthetically useful reaction but often lacks regioselectivity and stereocontrol. A significant challenge in the Meinwald rearrangement of internal epoxides is the non-regioselective migration of different substituents to give a mixture of products. Herein, an enzyme-catalyzed regioselective and stereospecific 1,2-methyl shift in the Meinwald rearrangement of internal epoxides is reported. Styrene oxide isomerase (SOI) catalyzed the unique isomerization of internal epoxides through 1,2methyl shift without 1,2-hydride shift to give the corresponding aldehydes and a cyclic ketone as the sole product. SOI-catalyzed isomerization showed high stereospecificity, fully retaining the stereoconfiguration. The synthetic utility of this enzymatic Meinwald rearrangement was demonstrated by its incorporation into three new types of enantioselective cascades, to convert transβ-methyl styrenes into the corresponding R-configured alcohols, acids, or amines in high ee and yield.