No abstract

Glomerular podocytes are highly specialized epithelial cells and play an essential role in establishing the selective permeability of the glomerular filtration barrier of kidney. Maintaining the viability and structural integrity of podocytes is critical to the clinical management of glomerular diseases, which requires a thorough understanding of podocyte cell biology. As mature podocytes lose proliferative capacity, a conditionally SV40 mutant tsA58-immortalized mouse podocyte line (designated as tsPC) was established from the Immortomouse over 20 years ago. However, the utility of the tsPC cells is hampered by the practical inconvenience of culturing these cells. In this study, we establish a user-friendly and reversibly-immortalized mouse podocyte line (designated as imPOD), on the basis of the tsPC cells by stably expressing the wildtype SV40 T-antigen, which is flanked with FRT sites. We show the imPOD cells exhibit long-term high proliferative activity, which can be effectively reversed by FLP recombinase. The imPOD cells express most podocyte-related markers, including WT-1, Nephrin, Tubulin and Vinculin, but not differentiation marker Synaptopodin. The imPOD cells do not form tumor-like masses in vivo. We further demonstrate that TGFβ1 induces a podocyte injury-like response in the FLP-reverted imPOD cells by suppressing the expression of slit diaphragm-associated proteins P-Cadherin and ZO-1 and upregulating the expression of mesenchymal markers, α-SMA, Vimentin and Nestin, as well as fibrogenic factors CTGF and Col1a1. Collectively, our results strongly demonstrate that the newly engineered imPOD cells should be a valuable tool to study podocyte biology both under normal and under pathological conditions.

Vascular calcification is a notable risk factor for cardiovascular system. High phosphate can induce calcification in vascular smooth muscle cells (VSMCs), but the detail mechanism underlying this process remains unclear. In the present study, we determined the relationship between high phosphate and bone morphogenetic protein 9 (BMP9) in VSMCs, the effect of BMP9 on calcification in VSMCs and the effect of COX-2 on BMP9 induced calcification in VSMCs, as well as the possible mechanism underlying this biological process. We found that high phosphate obviously up-regulates the expression of BMP9 in VSMCs. Over-expression of BMP9 decreases the level of alpha-smooth muscle cell actin (α-SMA) apparently, but increases the level of Runx-2, Dlx-5, and ALP in VSMCs. Meanwhile, BMP9 increases the level of OPN and OCN, promotes mineralization in VSMCs and induces calcification in thoracic aorta. High phosphate and over-expression of BMP9 increases the level of COX-2. Over-expression of COX-2 enhances the inhibitory effect of BMP9 on α-SAM and increases the level of OPN and OCN induced by BMP9. However, inhibition of COX-2 decreases the BMP9-induced calcification in VSMCs and thoracic aorta. For mechanism, we found that high phosphate or BMP9 increases the level of β-catenin and p-GSK3β in VSMCs, but no substantial effect on GSK3β. However, COX-2 inhibitor decreases the expression of β-catenin induced by BMP9. Our findings indicated that BMP9 is involved in the phosphate-induced calcification in VSMCs and COX-2 partly mediates the BMP9-induced calcification in VSMCs through activating Wnt/β-catenin pathway.

RNA interference (RNAi) is mediated by an ∼21-nt double-stranded small interfering RNA (siRNA) and shows great promise in delineating gene functions and in developing therapeutics for human diseases. However, effective gene silencing usually requires the delivery of multiple siRNAs for a given gene, which is often technically challenging and time-consuming. In this study, by exploiting the type IIS restriction endonuclease-based synthetic biology methodology, we developed the fast assembly of multiplex siRNAs (FAMSi) system. In our proof-of-concept experiments, we demonstrated that multiple fragments containing three, four, or five siRNA sites targeting common Smad4 and/or BMPR-specific Smad1, Smad5, and Smad8 required for BMP9 signaling could be assembled efficiently. The constructed multiplex siRNAs effectively knocked down the expression of Smad4 and/or Smad1, Smad5, and Smad8 in mesenchymal stem cells (MSCs), and they inhibited all aspects of BMP9-induced osteogenic differentiation in bone marrow MSCs (BMSCs), including decreased expression of osteogenic regulators/markers, reduced osteogenic marker alkaline phosphatase (ALP) activity, and diminished in vitro matrix mineralization and in vivo ectopic bone formation. Collectively, we demonstrate that the engineered FAMSi system provides a fast-track platform for assembling multiplexed siRNAs in a single vector, and thus it may be a valuable tool to study gene functions or to develop novel siRNA-based therapeutics.

No abstract

Hypoxia is a significant clinical feature and regulates various tumor processes in clear cell renal carcinoma (ccRCC). Increasing evidence has demonstrated that long non-coding RNAs (lncRNAs) are closely associated with the survival outcomes of ccRCC patients and regulates hypoxia-induced tumor processes. Thus, this study aimed to develop a hypoxia-related lncRNA (HRL) prognostic model for predicting the survival outcomes in ccRCC. LncRNAs in ccRCC samples were extracted from The Cancer Genome Atlas database. Hypoxia-related genes were downloaded from the Molecular Signatures Database. A co-expression analysis between differentially expressed lncRNAs and hypoxia-related genes in ccRCC samples was performed to identify HRLs. Univariate and multivariate Cox regression analyses were performed to select nine optimal lncRNAs for developing the HRL model. The prognostic model showed good performance in predicting prognosis among patients with ccRCC, and the validation sets reached consistent results. The model was also found to be related to the clinicopathologic parameters of tumor grade and tumor stage and to tumor immune infiltration. In conclusion, our findings indicate that the hypoxia-lncRNA assessment model may be useful for prognostication in ccRCC cases. Furthermore, the nine HRLs included in the model might be useful targets for investigating the tumorigenesis of ccRCC and designing individualized treatment strategies.

Cervical cancer is the fourth most common gynecological malignancy affecting the health of women worldwide and the second most common cause of cancer-related mortality among women in developing regions. Thus, the development of effective chemotherapeutic drugs for the treatment of cervical cancer has become an important issue in the medical field. The application of natural products for the prevention and treatment of various diseases, particularly cancer, has always attracted widespread attention. In the present study, a library of natural products composed of 78 single compounds was screened and it was found that digitoxin exhibited the highest cytotoxicity against HeLa cervical cancer cells with an IC 50 value of 28 nM at 48 h. Furthermore, digitoxin exhibited extensive antitumor activities in a variety of malignant cell lines, including the lung cancer cell line, A549, the hepatoma cell line, MHCC97H, and the colon cancer cell line, HCT116. Mechanistically, digitoxin caused DNA double-stranded breaks (DSBs), inhibited the cell cycle at the G 2 /M phase via the ataxia telangiectasia mutated serine/threonine kinase (ATM)/ATM and Rad3-related serine/threonine kinase (ATR)-checkpoint kinase (CHK1)/checkpoint kinase 2 (CHK2)-Cdc25C pathway and ultimately triggered mitochondrial apoptosis, which was characterized by the disruption of Bax/Bcl-2, the release of cytochrome c and the sequential activation of caspases and poly(ADP-ribose) polymerase (PARP). In addition, the in vivo anticancer effect of digitoxin was confirmed in HeLa cell xenotransplantation models. On the whole, the findings of the present study demonstrate the efficacy of digitoxin against cervical cancer in vivo and elucidate its molecular mechanisms, including DSBs, cell cycle arrest and mitochondrial apoptosis. These results will contribute to the development of digitoxin as a chemotherapeutic agent in the treatment of cervical cancer.

Background It is unclear whether short‐term blood pressure variability is associated with renal outcomes in patients with chronic kidney disease. Methods and Results This study analyzed data from participants in the C‐ STRIDE (Chinese Cohort Study of Chronic Kidney Disease) who had chronic kidney disease stages 1 to 4. Short‐term blood pressure variability was measured by calculating the weighted SD (w‐ SD ) of systolic blood pressure ( SBP ). Renal outcomes were defined as dialysis initiation and/or transplantation. Risk factors associated with w‐ SD of SBP were evaluated by linear regression. Associations of short‐term SBP variability with renal outcomes were evaluated by Cox regression. In total, 1421 patients with chronic kidney disease were included in this study (mean age, 49.4±13.6 years; 56.2% men; estimated glomerular filtration rate, 50.5±29.3 mL/min per 1.73 m 2 ; proteinuria, 0.9 [0.3–2.0] g/d). Mean w‐ SD of SBP was 12.6±4.4 mm Hg. w‐ SD of SBP was independently associated with older age, 24‐hour SBP , blood pressure circadian pattern, and angiotensin II receptor blocker treatment. During a median follow‐up of 4.9 years, 237 patients developed renal outcomes (37.01 per 1000 patient‐years). The incidence rate increased across the quartiles of w‐ SD (log‐rank P =0.005). w‐ SD of SBP was associated with an increased risk of renal outcomes, both as a continuous variable (hazard ratio [HR], 1.47; 95% CI, 1.09–1.99) and as a categorical variable (quartile 4 versus quartile 1: HR, 1.60; 95% CI, 1.08–2.36), independent of 24‐hour SBP , daytime SBP , and nighttime SBP . Conclusions Short‐term SBP was independently associated with the risk of dialysis initiation and/or transplantation in patients with chronic kidney disease .