Dissected Leaf 1 encodes an MYB transcription factor that controls leaf morphology in potato.

KEY MESSAGE: The transcription factor StDL1 regulates dissected leaf formation in potato and the genotype frequency of recessive Stdl1/Stdl1, which results in non-dissected leaves, has increased in cultivated potatoes. Leaf morphology is a key trait of plants, influencing plant architecture, photosynthetic efficiency and yield. Potato (Solanum tuberosum L.), the third most important food crop worldwide, has a diverse leaf morphology. However, despite the recent identification of several genes regulating leaf formation in other plants, few genes involved in potato leaf development have been reported. In this study, we identified an R2R3 MYB transcription factor, Dissected Leaf 1 (StDL1), regulating dissected leaf formation in potato. A naturally occurring allele of this gene, Stdl1, confers non-dissected leaves in young seedlings. Knockout of StDL1 in a diploid potato changes the leaf morphology from dissected to non-dissected. Experiments in N. benthamiana and yeast show that StDL1 is a transcriptional activator. Notably, by calculating the genotype frequency of the Stdl1/Stdl1 in 373-potato accessions, we found that it increases significantly in cultivated potatoes. This work reveals the genetic basis of dissected leaf formation in potato and provides insights into plant leaf morphology.

Epicardial Adipose Tissue Measured From Computed Tomography Predicts Cardiac Resynchronization Therapy Response in Patients With Non-ischemic Systolic Heart Failure.

Background: Epicardial adipose tissue (EAT) has been linked with the pathogenesis of heart failure (HF). Limited data have been reported about the clinical value of EAT for cardiac resynchronization therapy (CRT) in non-ischemic systolic HF. We aimed to explore the values of EAT measured from CT to predict the response to CRT in patients with non-ischemic systolic HF. Methods: Forty-one patients with CRT were consecutively recruited for our study. All patients received both gated resting Single Photon Emission CT (SPECT) myocardial perfusion imaging (MPI) and dual-source multi-detector row CT scans. EAT thickness was assessed on both the parasternal short and horizontal long-axis views. The area of EAT was calculated at the left main coronary artery level. Left ventricular systolic mechanical dyssynchrony (LVMD) was measured by phase standard deviation (PSD) and phase histogram bandwidth (PBW). The definition of CRT response was an improvement of 5% in left ventricular ejection fraction (LVEF) at 6 months after CRT implantation. Results: After 6 months of follow-up, 58.5% (24 of 41) of patients responded to CRT. A greater total perfusion deficit (TPD) was observed in the left ventricle, and a narrower QRS complex was observed in the nonresponse group than in the response group (p < 0.05). Meanwhile, the systolic PSD and systolic PBW were statistically greater in the CRT group with no response than in the response group (p < 0.05). Meanwhile, the baseline QRS duration, TPD, systolic PSD, systolic PBW, EAT thicknesses of the left ventricular (LV) apex, right atrioventricular (AV) groove, and left AV groove were all significantly related to the CRT response in the univariate logistic regression analysis. Furthermore, the QRS duration and EAT thicknesses of the right AV groove and left AV groove were independent predictors of CRT response in the multivariate logistic regression analysis. Conclusions: The EAT thickness of the left AV groove in patients with non-ischemic systolic HF is associated with the TPD of LV and LV systolic dyssynchrony. The EAT thickness of the AV groove has a good predictive value for the CRT response in patients with non-ischemic systolic HF.

Multi-parametric cellular imaging coupled with multi-component quantitative profiling for screening of hepatotoxic equivalent markers from Psoraleae Fructus.

BACKGROUND: The hepatotoxicity of Chinese herbal medicine (CHM) is an important reason for its restrictive application. Psoraleae Fructus (PF), a commonly used CHM for treatment of osteoporosis and vitiligo etc., has caused serious concern due to the frequent occurrence of liver injury incidents. To date, its hepatotoxic equivalent markers (HEMs) and potential mechanisms are still unclear. PURPOSE: To discover and validate the HEMs of PF and further explore the potential mechanisms of hepatotoxicity. METHODS: Multi-parametric cellular imaging was performed by high content screening, and multi-component quantitative profiling was conducted by ultra-high performance liquid chromatography coupled with triple-quadrupole mass spectrometry. The correlations between hepatotoxic features and component contents were modeled by chemometrics including partial least square regression, back propagation-artificial neural network, and hierarchical cluster analysis. Then the candidate HEMs of PF were screened out and subjected to hepatotoxic equivalence assessment in primary hepatocytes, zebrafish, and mice, and the hepatotoxic mechanisms of PF were investigated. RESULTS: The chemical combination of psoralen and isopsoralen was discovered as the HEMs of PF through pre-screening and verifying process. PF was demonstrated to induce oxidative stress, mitochondrial dysfunction and cellular apoptosis. CONCLUSIONS: This study not only provides a rational strategy for screening HEMs from CHMs like PF, but also contributes to understanding the underlying mechanisms of PF hepatotoxicity.

A novel mutation in KCNH2 yields loss-of-function of hERG potassium channel in long QT syndrome 2.

Mutations in hERG (human ether-à-go-go-related gene) potassium channel are closely associated with long QT syndromes. By direct Sanger sequencing, we identified a novel KCNH2 mutation W410R in the patient with long QT syndrome 2 (LQT2). However, the electrophysiological functions of this mutation remain unknown. In comparison to hERGWT channels, hERGW410R channels have markedly decreased total and surface expressions. W410R mutation dramatically reduces hERG channel currents (IKr) and shifts its steady-state activation curve to depolarization. Moreover, hERGW410R channels make dominant-negative effects on hERGWT channels. Significantly, we find hERG channel blocker E-4031 could partially rescue the function of hERGW410R channels by increasing the membrane expression. By using in silico model, we reveal that hERGW410R channels obviously elongate the repolarization of human ventricular myocyte action potentials. Collectively, W410R mutation decreases the currents of hERG channel, because of diminished membrane expression of mutant channels, that subsequently leads to elongated repolarization of cardiomyocyte, which might induce the pathogenesis of LQT2. Furthermore, E-4031 could partially rescue the decreased activity of hERGW410R channels. Thus, our work identifies a novel loss-of-function mutation in KCNH2 gene, which might provide a rational basis for the management of LQT2.

Binary Colloidal Crystals Drive Spheroid Formation and Accelerate Maturation of Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes.

The development of human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) provides significant advances to cell therapy, disease modeling, and drug screening applications. However, the current differentiation protocol is inefficient in mimicking biophysical and biochemical characteristics of cardiac niche. Hence, immature cardiomyocytes are often generated. In this study, hiPSC-CMs were generated on a new family of substrates called monolayer binary colloidal crystals (BCCs). Four BCCs were fabricated with different sizes (2 or 5 or 0.4 or 0.2 µm) and materials [Si or polystyrene (PS) or poly(methyl methacrylate)] abbreviated as 2PS, 5PS, 2PM, and 5PM. BCCs have complex surface micro-/nanotopographies and heterogeneous chemistries which are important modulators in microenvironments in vitro. The results showed that hiPSCs formed adhered spheroids with strong pluripotent markers ( Oct4, Nanog, and Sox2) on PM surfaces compared to PS and flat surfaces. After 30-day differentiation, hiPSC-CMs on PM surfaces showed markedly improved myofibril ultrastructures, Ca2+ handling, and electrophysiological properties, indicating that more mature hiPSC-CMs were generated. hiPSC-CMs generated on 5PM are more similar to adult heart tissue compared to other surfaces in terms of genes ( ACTC1, TNNT2, RYR2, SERCA2a, SCN5a, KCNJ2, CACNA1c, ITGB1, GJA1, MYH6, and MYH7) and protein (ssTnI and cTnI) expressions. We further demonstrated that 5PM surfaces facilitated cadherin switching (from E- to N-) during cardiac differentiation and mature N-cadherin expression, which were positively correlated with the cardiogensis markers ( GATA4, MEF2c, and NKX2.5). This study illuminated that a tailored surface nanotopography was beneficial in hiPSC culture and in situ cardiac differentiation. This one-step approach and BCCs can be a next-generation tool for hiPSC expansion and CM differentiation.

Functional characterization of Autographa californica multiple nucleopolyhedrovirus gp16 (ac130).

To investigate the function of Autographa californica multiple nucleopolyhedrovirus (AcMNPV) gp16, multiple gp16-knockout and repair mutants were constructed and characterized. No obvious difference in productivity of budded virus, DNA synthesis, late gene expression and morphogenesis was observed between gp16-knockout and repair viruses, but gp16 deletion resulted in six hours of lengthening in ST50 to the third instar Spodoptera exigua larvae in bioassays. GP16 was fractionated mainly in the light membrane fraction, by subcellular fractionation. A GP16-EGFP fusion protein was predominantly localized close around the nuclear membrane in infected cells, being coincident with formation of the vesicles associated with the nuclear membrane, which hosted nucleocapsids released from the nucleus. These data suggest that gp16 is not required for viral replication, but may be involved in membrane trafficking associated with the envelopment/de-envelopment of budded viruses when they cross over the nuclear membrane and pass through cytoplasm.

Effects of Early or Overexpression of the Autographa californica Multiple Nucleopolyhedrovirus orf94 (ODV-e25) on Virus Replication.

odv-e25(e25) is one of the core genes of baculoviruses. To investigate how it functions in the replication cycle of a baculovirus, a number of Autographa californica multiple nucleopolyhedrovirus recombinants with e25 under control of the promoter of immediate early gene ie1, or the promoter of the very late hyperexpressed gene p10, were constructed using a bacmid system, and the effects of early expression or overexpression of e25 on replication of the virus were evaluated. Microscopy and titration assays demonstrated that bacmids with e25 under control of ie1 promoter were unable to produce budded viruses; and that the recombinant viruses with e25 under control of p10 promoter generated budded virus normally, but formation of occlusion bodies were dramatically reduced and delayed in the infected cells. Electron microscopy showed that there were no mature virions or intact nucleocapsids present in the cells transfected with a recombinant bacmid with e25 under control of ie1 promoter. Quantitative real-time PCR analysis demonstrated that alteration of the e25 promoter did not affect viral DNA synthesis. The reporter gene expression from the promoter of the major capsid protein gene vp39 was reduced 63% by early expression of e25. Confocal microscopy revealed that E25 was predominantly localized in nuclei by 24 hours post infection with wild-type virus, but it remained in the cytoplasm in the cells transfected with a recombinant bacmid with e25 under control of the ie1 promoter, suggesting that the transport of E25 into nuclei was regulated in a specific and strict time dependent manner.