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Acute kidney injury (AKI) with maladaptive tubular repair leads to renal fibrosis and progresses to chronic kidney disease (CKD). At present, there is no curative drug to interrupt AKI-to-CKD progression. The nuclear factor of the activated T cell (NFAT) family was initially identified as a transcription factor expressed in most immune cells and involved in the transcription of cytokine genes and other genes critical for the immune response. NFAT2 is also expressed in renal tubular epithelial cells (RTECs) and podocytes and plays an important regulatory role in the kidney. In this study, we investigated the renoprotective effect of 11R-VIVIT, a peptide inhibitor of NFAT, on renal fibrosis in the AKI-to-CKD transition and the underlying mechanisms. We first examined human renal biopsy tissues and found that the expression of NFAT2 was significantly increased in RTECs in patients with severe renal fibrosis. We then established a mouse model of AKI-to-CKD transition using bilateral ischemia-reperfusion injury (Bi-IRI). The mice were treated with 11R-VIVIT (5 mg/kg, i.p.) on Days 1, 3, 10, 17 and 24 after Bi-IRI. We showed that the expression of NFAT2 was markedly increased in RTECs in the AKI-to-CKD transition. 11R-VIVIT administration significantly inhibited the nuclear translocation of NFAT2 in RTECs, decreased the levels of serum creatinine and blood urea nitrogen, and attenuated renal tubulointerstitial fibrosis but had no toxic side effects on the heart and liver. In addition, we showed that 11R-VIVIT administration alleviated RTEC apoptosis after Bi-IRI. Consistently, preapplication of 11R-VIVIT (100 nM) and transfection with NFAT2-targeted siRNA markedly suppressed TGFβ-induced HK-2 cell apoptosis in vitro. In conclusion, 11R-VIVIT administration inhibits IRI-induced NFAT2 activation and prevents AKI-to-CKD progression. Inhibiting NFAT2 may be a promising new therapeutic strategy for preventing renal fibrosis after IR-AKI.

The emodin-involved hepatotoxicity has been gaining increasing attention. The purpose of the present study was to evaluate the cytotoxicity of emodin on cultured human liver cells (L-02) and predict the possible relation between its cytotoxicity and cellular toxicokinetics. Cell viability and cell damage were assessed by Cell Counting Kit-8 (CCK-8) assay and phase-contrast microscopy, respectively. Cytotoxicity tests demonstrated a concentration- and time-dependent toxic effect of emodin on L-02 cells. Furthermore, emodin at concentration of 30μM led to a significant apoptosis in a time-dependent manner supported by the morphological changes of drug-treated cells. In addition, to elucidate the toxicokinetic characteristics of emodin, a highly sensitive and selective liquid chromatography-mass spectrometry (LC-MS) method was employed and validated for detecting the dynamic alteration of emodin in cells and cell culture media. The proposed method appeared to be suitable for the analysis of emodin with desirable linearity (r(2)>0.99), and satisfying precision being less than 8.7%. The range of recoveries of this method was 90.2-101.9%. The preliminary cellular toxicokinetic study revealed a time-dependent intracellular accumulation of emodin, which was consistent with its in vitro toxic effects. These findings confirmed the cytotoxicity of emodin against L-02 cells and displayed the cytotoxic manner of emodin in terms of its cellular uptake and accumulation in L-02 cells.

Complications of microocclusions have been reported after intra-arterial delivery of mesenchymal stromal cells. Hence, quantification and efficient limitation of cell clumps in suspension before transplantation is important to reduce the risk. We used a flow cytometry-based pulse-width assay to assess the effects of different cell suspension concentrations (0.2-2.0 × 106/mL), storage solutions (complete growth medium, Dulbecco's phosphate-buffered saline, and normal saline), storage time in suspension (0-9 h), and freeze-thawing procedure on the clumping of rat bone marrow derived mesenchymal stromal cells (BMMSCs) and also evaluated cell viability at the same time. Surprisingly, increasing the cell concentration did not result in more cell clumps in vitro. Freshly harvested (fresh) cells in normal saline had significantly fewer cell clumps and also displayed high viability (>90%). A time-dependent reduction in viability was observed for cells in all three storage solutions, without any significant change in the clumping tendency except for cells in medium. Fresh cells were more viable than their frozen-thawed counterparts, and fresh cells in normal saline had fewer cell clumps. In conclusion, cell clumping and viability could be affected by different cell preparation procedures, and quantification of cell clumping can be conducted using the flow cytometry-based pulse-width assay before intra-arterial cell delivery.

A scheme is proposed to obtain slow light in a coulped quantum wells microcavity with tunneling induced transparency between intersubband electronic transitions. Three prolaritons are created by intracavity Fano interference between fundamental mode photon and two quantum oscillators of coherent subband electronic excitations. A narrow middle dark polariton of the three can be produced, which can be used to suppress the line profiles of the transmission or reflection spectra for the incident light. This leads to slow propagation of the incident light in the microcavity. The semiconductor optical microcavity can be an alternative choice of quantum photoelectronic devices in nanoscale.