Identification of New Transcription Factors that Can Promote Pluripotent Reprogramming

Background Four transcription factors, Oct4, Sox2, Klf4, and c-Myc (the Yamanka factors), can reprogram somatic cells to induced pluripotent stem cells (iPSCs). Many studies have provided a number of alternative combinations to the non-Yamanaka factors. However, it is clear that many additional transcription factors that can generate iPSCs remain to be discovered. Methods The chromatin accessibility and transcriptional level of human embryonic stem cells and human urine cells were compared by Assay for Transposase-Accessible Chromatin with high-throughput sequencing (ATAC-seq) and RNA sequencing (RNA-seq) to identify potential reprogramming factors. Selected transcription factors were employed to reprogram urine cells, and the reprogramming efficiency was measured. Urine-derived iPSCs were detected for pluripotency by Immunofluorescence, quantitative polymerase chain reaction, RNA sequencing and teratoma formation test. Finally, we assessed the differentiation potential of the new iPSCs to cardiomyocytes in vitro. Results ATAC-seq and RNA-seq datasets predicted TEAD2, TEAD4 and ZIC3 as potential factors involved in urine cell reprogramming. Transfection of TEAD2, TEAD4 and ZIC3 (in the presence of Yamanaka factors) significantly improved the reprogramming efficiency of urine cells. We confirmed that the newly generated iPSCs possessed pluripotency characteristics similar to normal H1 embryonic stem cells. We also confirmed that the new iPSCs could differentiate to functional cardiomyocytes. Conclusions In conclusion, TEAD2, TEAD4 and ZIC3 can increase the efficiency of reprogramming human urine cells into iPSCs, and provides a new stem cell sources for the clinical application and modeling of cardiovascular disease. Graphical abstract

Up-Regulated Expression of Pro-Apoptotic Long Noncoding RNA lincRNA-p21 with Enhanced Cell Apoptosis in Lupus Nephritis

Accelerated cell apoptosis with dysregulated long noncoding RNAs is the crucial pathogenesis in lupus nephritis (LN). Pro-apoptotic lincRNA-p21 was studied in LN patients, cell lines with lentivirus-mediated overexpression and CRISPR interference (CRISPRi)-conducted repression, and a mouse model. Clinical samples were from patients and age/sex-matched controls. Expression of lincRNA-p21 and endogenous RNA target miR-181a, were examined in mononuclear and urine cells. Guide RNA sequences targeting lincRNA-p21 were cloned into CRISPRi with dCas9/ Krüppel-associated box (KRAB) domain. LincRNA-p21-silened transfectants were investigated for apoptosis and miR-181a expression. LincRNA-p21-overexpressed cells were evaluated for apoptosis and p53-related down-stream molecules. Balb/C mice were injected with pristane to induce LN and examined for apoptosis and lincRNA-p21. Higher lincRNA-p21 levels were found in LN mononuclear and urine cells, positively correlated with activity. There were lower miR-181a levels in LN mononuclear cells, negatively correlated with activity. Doxorubicin-induced apoptotic cells had up-regulated lincRNA-p21 levels. CRISPRi with dCas9/KARA domain showed efficient repression ability on transcription initiation/elongation. CRISPRi-conducted lincRNA-p21-silenced transfectants displayed reduced apoptosis with up-regulated miR-181a levels, whereas lentivirus-mediated lincRNA-p21-overexpressed cells revealed enhanced apoptosis with up-regulated downstream PUMA/Bax expression. LN mice had glomerular apoptosis with progressive increased lincRNA-p21 levels. Our results demonstrate up-regulated lincRNA-p21 expression in LN, implicating a potential diagnostic marker and therapeutic target.

Up-Regulated Expression of Pro-Apoptotic Long Noncoding RNA lincRNA-p21 in Lupus Nephritis Patients and an Experimental Mouse Model

Background: Accelerated cell apoptosis is a crucial pathogenic mechanism in lupus nephritis (LN) with dysregulated expression levels of long noncoding RNAs (lncRNAs). The expression of pro-apoptotic lincRNA-p21 and its competing endogenous RNA target miR-181a were studied in LN patients, human kidney cell and T-lymphocyte lines with CRISPR interference-conducted repression and lentiviral vector-mediated overexpression of lincRNA-p21, and a mouse LN model. Methods: Clinical samples were collected from LN patients with higher disease activity and control subjects including lupus patients without renal involvement and age/sex-matched healthy controls (HCs). The expression of lincRNA-p21, H19 (anti-apoptotic lncRNA) and miR-181a were examined in peripheral blood mononuclear cells (PBMNCs) and urine cells, and analyzed for clinical correlation. Cell lines were treated with doxorubicin (Dox) to induce apoptosis and evaluate for the expression of lincRNA-p21, caspase 3 and p21. LincRNA-p21-silened HEK 293T and Jurkat transfectants were examined for apoptosis and miR-181a expression. LincRNA-p21-overexpressed HK-2 cells were examined for apoptosis and p53-related down-stream molecules levels. Female Balb/C mice were injected with pristane to induce LN, and examined for the expression of anti-DNA, proteinuria, lincRNA-p21, caspase 3 and p21 as well as in situ apoptosis. Results: Up-regulated expression of lincRNA-p21 rather than H19 were identified in PBMNCs from LN patients, positively correlated with disease activity and proteinuria amount. Higher lincRNA-p21 levels were identified in LN CD4+T cells than other subpopulations. LN urine cells had greater lincRNA-p21 levels than HCs. There were lower miR-181a levels in PBMNCs from LN patients, negatively correlated with disease activity. Dox-induced apoptotic cell lines had up-regulated levels of lincRNA-p21, caspase 3 and p21, whereas down-regulated miR-181a expression with decreased TCRζchain and IL-2 levels was identified in Jurkat cells. LincRNA-p21-silenced transfectants displayed reduced apoptosis with up-regulated miR-181a expression. LincRNA-p21-overexpressed HK-2 cells revealed enhanced apoptosis with up-regulated expression of downstream PUMA and Bax molecules. LN mice had in situ apoptosis and progressively increased anti-dsDNA, proteinuria and renal lincRNA-p21 levels with up-regulated expression of caspase 3 and p21.Conclusions: By using clinical samples, human cell lines and a mouse model, we demonstrate up-regulated expression of lincRNA-p21 in LN, implicating a potential activity biomarker and therapeutic target.

Urine-Derived Induced Pluripotent Stem Cells in Cardiovascular Disease

Recent studies have demonstrated that stem cells are equipped with the potential to differentiate into various types of cells, including cardiomyocytes. Meanwhile, stem cells are highly promising in curing cardiovascular diseases. However, owing to the ethical challenges posed in stem cell acquisition and the complexity and invasive nature of the method, large-scale expansions and clinical applications in the laboratory have been limited. The current generation of cardiomyocytes is available from diverse sources; urine is one of the promising sources among them. Although advanced research was established in the generation of human urine cells as cardiomyocytes, the reprogramming of urine cells to cardiomyocytes remains unclear. In this context, it is necessary to develop a minimally invasive method to create induced pluripotent stem cells (iPSCs). This review focuses on the latest advances in research on urine-derived iPSCs and their application mechanisms in cardiovascular diseases.

Direct Conversion of Human Urine Cells to Neurons by Small Molecules

Transdifferentiation of other cell type into human neuronal cells (hNCs) provides a platform for neural disease modeling, drug screening and potential cell-based therapies. Among all of the cell donor sources, human urine cells (hUCs) are convenient to obtain without invasive harvest procedure. Here, we report a novel approach for the transdifferentiation of hUCs into hNCs. Our study demonstrated that a combination of seven small molecules (CAYTFVB) cocktail induced transdifferentiation of hUCs into hNCs. These chemical-induced neuronal cells (CiNCs) exhibited typical neuron-like morphology and expressed mature neuronal markers. The neuronal-like morphology revealed in day 1, and the Tuj1-positive CiNCs reached to about 58% in day 5 and 38.36% Tuj1+/MAP2+ double positive cells in day 12. Partial electrophysiological properties of CiNCs was obtained using patch clamp. Most of the CiNCs generated using our protocol were glutamatergic neuron populations, whereas motor neurons, GABAergic or dopaminergic neurons were merely detected. hUCs derived from different donors were converted into CiNCs in this work. This method may provide a feasible and noninvasive approach for reprogramming hNCs from hUCs for disease models and drug screening.