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Diabetes mellitus is a serious metabolic condition associated with a multitude of cardiovascular complications. Moreover, the prevalence of diabetes in heart failure populations is higher than that in control populations. However, the role of cardiomyocyte alterations in type 2 diabetes mellitus (T2DM) has not been well characterized and the underlying mechanisms remain elusive. In this study, two patients who were diagnosed as T2DM were recruited and patient-specific induced pluripotent stem cells (iPSCs) were generated from urine epithelial cells using nonintegrated Sendai virus. The iPSC lines derived from five healthy subjects were used as controls. All iPSCs were differentiated into cardiomyocytes (iPSC-CMs) using the monolayer-based differentiation protocol. T2DM iPSC-CMs exhibited various disease phenotypes, including cellular hypertrophy and lipid accumulation. Moreover, T2DM iPSC-CMs exhibited higher susceptibility to high-glucose/high-lipid challenge than control iPSC-CMs, manifesting an increase in apoptosis. RNA-Sequencing analysis revealed a differential transcriptome profile and abnormal activation of TGFβ signaling pathway in T2DM iPSC-CMs. We went on to show that inhibition of TGFβ significantly rescued the hypertrophic phenotype in T2DM iPSC-CMs. In conclusion, we demonstrate that the iPSC-CM model is able to recapitulate cellular phenotype of T2DM. Our results indicate that iPSC-CMs can therefore serve as a suitable model for investigating molecular mechanisms underlying diabetic cardiomyopathies and for screening therapeutic drugs.

Summary Atypical hemolytic uremic syndrome (aHUS) is a rare disease associated with high morbidity and mortality. Existing evidence suggests that the central pathogenesis to aHUS might be endothelial cell damage. Nevertheless, the role of endothelial cell alterations in aHUS has not been well characterized and the underlying mechanisms remain unclear. Utilizing an induced pluripotent stem cell-derived endothelial cell (iPSC-EC) model, we showed that anti-complement factor H autoantibody-associated aHUS patient-specific iPSC-ECs exhibited an intrinsic defect in endothelial functions. Stimulation using aHUS serums exacerbated endothelial dysfunctions, leading to cell apoptosis in iPSC-ECs. Importantly, we identified p38 as a novel signaling pathway contributing to endothelial dysfunctions in aHUS. These results illustrate that iPSC-ECs can be a reliable model to recapitulate EC pathological features, thus providing a unique platform for gaining mechanistic insights into EC injury in aHUS. Our findings highlight that the p38 MAPK signaling pathway can be a therapeutic target for treatment of aHUS., Graphical abstract, Highlights • aHUS patient-specific iPSC-ECs exhibit intrinsic defect in endothelial functions • Stimulation using aHUS serums exacerbates EC dysfunctions and causes EC apoptosis • p38 signaling contributes to EC dysfunctions in anti-CFH Ab-associated aHUS, In this article, Liang and colleagues successfully generate patient-specific iPSCs from anti-CFH autoantibody-associated aHUS. They demonstrate that aHUS iPSC-ECs exhibit an intrinsic defect in endothelial functions. Stimulation of aHUS sera exacerbates EC dysfunctions and causes EC apoptosis. Mechanistically, p38 signaling is significantly downregulated, contributing to the observed endothelial phenotypes, which may serve as a therapeutic target for treatment of the disease.

Cardiac hypertrophy is an adaptive response against increased workload featuring by an increase in left ventricular mass and a thickening left ventricle wall. Here, we showed the expression of transient receptor potential canonical 1 (TRPC1) is higher in hearts of patients with hypertrophic cardiomyopathy (HCM) or heart failure (HF) than that of normal hearts. To better understand the mechanisms of TRPC1 in regulating cellular hypertrophy of human-based cardiomyocytes, we generated human pluripotent stem cell lines of TRPC1 knockout by CRISPR/Cas9. We demonstrated that knockout of TRPC1 significantly attenuated cardiomyocyte hypertrophy phenotype induced by phorbol 12-myristate 13-acetate, which was associated with abnormal activation of NF-κB. In contrast, overexpression of TRPC1 induced cardiomyocyte hypertrophy, which can be reversed by inhibition of NF-κB. Taken together, we established a stable human-based cardiomyocyte hypertrophy model and highlighted molecular mechanisms underlying TRPC1-mediated hypertrophy, aiding the development of therapeutic drugs for HCM and HF by targeting TRPC1.

Cadmium, a highly ubiquitous toxic heavy metal, has been widely recognized as an environmental and industrial pollutant, which confers serious threats to human health. The molecular mechanisms of the cadmium‐induced cardiotoxicity (CIC) have not been studied in human cardiomyocytes at the cellular level. Here we showed that human pluripotent stem cell‐derived cardiomyocytes (hPSC‐CMs) can recapitulate the CIC at the cellular level. The cadmium‐treated hPSC‐CMs exhibited cellular phenotype including reduced cell viability, increased apoptosis, cardiac sarcomeric disorganization, elevated reactive oxygen species, altered action potential profile and cardiac arrhythmias. RNA‐sequencing analysis revealed a differential transcriptome profile and activated MAPK signalling pathway in cadmium‐treated hPSC‐CMs, and suppression of P38 MAPK but not ERK MAPK or JNK MAPK rescued CIC phenotype. We further identified that suppression of PI3K/Akt signalling pathway is sufficient to reverse the CIC phenotype, which may play an important role in CIC. Taken together, our data indicate that hPSC‐CMs can serve as a suitable model for the exploration of molecular mechanisms underlying CIC and for the discovery of CIC cardioprotective drugs.

Most of the horticultural products are highly perishable and reducing their postharvest losses is extremely important. There is a worldwide trend to explore new alternatives to increase shelf life and postharvest quality of horticultural products. This review discusses the use of gaseous and some other low molecular mass compounds as a feasible way to maintain quality and prolong shelf life of rapidly deteriorating horticultural products during postharvest stage. These compounds including nitric oxide (NO), carbon monoxide (CO), hydrogen sulfide (H2S), hydrogen peroxide (H2O2), hydrogen gas (H2), carbon dioxide (CO2) and chlorine dioxide (ClO2) could delay horticultural products senescence through different mechanisms such as suppressing respiration rate, inhibiting ethylene biosynthesis, delaying browning and regulating activity of antioxidant enzymes. The review also summarizes the interaction between these molecules and ethylene during horticultural products senescence process. Additionally, NO may cross talk with H2O2 or H2S to promote the quality and prolong the postharvest life of perishable fruits and vegetables. Those compounds regulate the expression of genes during senescence, including ethylene biosynthesis related genes, lipoxygenase gene, cysteine protease gene and chlorophyll degradation related genes. Because of the obvious benefits of these compounds to postharvest freshness of fresh-cut flowers, fruits and vegetables, this area has been and will continue to be one of the priorities of horticultural research in the future.

H2 prolonged the vase life and improved the vase quality of cut roses through repressing endogenous ethylene production and alleviating ethylene signal transduction during the entire senescing period. Recently, the application of hydrogen gas (H2) was shown to improve postharvest quality and longevity in perishable horticultural products, but the specific regulation mechanism remains obscure. Here, endogenous ethylene production and the expression of genes in ethylene biosynthesis and signalling pathway were investigated to explore the crosstalk between H2 and ethylene during the senescence of cut roses. Our results revealed that addition of exogenous ethylene by ethephon accelerated the senescence of cut roses, in which 100 mg L−1 ethephon displayed the most obvious senescent phenotype. While the applied different concentrations (1%, 10%, 50% and 100%) of hydrogen-rich water (HRW) conducted different affects in alleviating the senescence of cut roses, and 1% HRW displayed the best ornamental quality and the longest vase life by reducing ethylene production, supported by the decrease of 1-aminocyclopropene-1-carboxylate (ACC) accumulation, ACC synthase (ACS) and ACC oxidase (ACO) activities, and Rh-ACS3 and Rh-ACO1 expressions in ethylene biosynthesis. In addition, HRW increased the transcripts of ethylene receptor genes Rh-ETR1 at blooming period from day 4 to day 6 and suppressed Rh-ETR3 at senescence phase at day 8 after harvest. Furthermore, the relevant affection of HRW on Rh-ETR1 and Rh-ETR3 expressions still existed when the ethylene production was compromised by adequate addition of exogenous ethylene in HRW-treated cut rose petals, and HRW directly repressed the protein level of Rh-ETR3 in a transient expression assay. Overall, the results suggested that H2 is involved in neutralizing ethylene-mediated postharvest in cut flowers.

© 2016 American College of Cardiology Foundation Background Brugada syndrome (BrS), a disorder associated with characteristic electrocardiogram precordial ST-segment elevation, predisposes afflicted patients to ventricular fibrillation and sudden cardiac death. Despite marked achievements in outlining the organ level pathophysiology of the disorder, the understanding of human cellular phenotype has lagged due to a lack of adequate human cellular models of the disorder. Objectives The objective of this study was to examine single cell mechanism of Brugada syndrome using induced pluripotent stem cell–derived cardiomyocytes (iPSC-CMs). Methods This study recruited 2 patients with type 1 BrS carrying 2 different sodium voltage-gated channel alpha subunit 5 variants as well as 2 healthy control subjects. We generated iPSCs from their skin fibroblasts by using integration-free Sendai virus. We used directed differentiation to create purified populations of iPSC-CMs. Results BrS iPSC-CMs showed reductions in inward sodium current density and reduced maximal upstroke velocity of action potential compared with healthy control iPSC-CMs. Furthermore, BrS iPSC-CMs demonstrated increased burden of triggered activity, abnormal calcium (Ca2+) transients, and beating interval variation. Correction of the causative variant by genome editing was performed, and resultant iPSC-CMs showed resolution of triggered activity and abnormal Ca2+ transients. Gene expression profiling of iPSC-CMs showed clustering of BrS compared with control subjects. Furthermore, BrS iPSC-CM gene expression correlated with gene expression from BrS human cardiac tissue gene expression. Conclusions Patient-specific iPSC-CMs were able to recapitulate single-cell phenotype features of BrS, including blunted inward sodium current, increased triggered activity, and abnormal Ca2+handling. This novel human cellular model creates future opportunities to further elucidate the cellular disease mechanism and identify novel therapeutic targets.

Rationale: Short QT syndrome (SQT) is a rare but arrhythmogenic disorder featured by shortened ventricular repolarization and a propensity toward life-threatening ventricular arrhythmias and sudden cardiac death. Objective: This study aimed to investigate the single-cell mechanism of SQT using patient-specific and gene-corrected induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs). Methods and Results: One SQT patient carrying missense mutation T618I in potassium voltage-gated channel subfamily H member 2 ( KCNH2 ) was recruited as well as 2 healthy control subjects in this study. Control and SQT patient-specific iPSCs were generated from skin fibroblasts using nonintegrated Sendai virus. The KCNH2 T618I mutation was corrected by genome editing in SQT iPSC lines to generate isogenic controls. All iPSCs were differentiated into iPSC-CMs using monolayer-based differentiation protocol. SQT iPSC-CMs exhibited abnormal action potential phenotype featured by shortened action potential duration and increased beat-beat interval variability, when compared with control and gene-corrected iPSC-CMs. Furthermore, SQT iPSC-CMs showed KCNH2 gain-of-function with increased rapid delayed rectifying potassium current (I Kr ) density and enhanced membrane expression. Gene expression profiling of iPSC-CMs exhibited a differential cardiac ion-channel gene expression profile of SQT. Moreover, QTc of SQT patient and action potential durations of SQT iPSC-CMs were both normalized by quinidine, indicating that quinidine is beneficial to KCNH2 T618I of SQT. Importantly, shortened action potential duration phenotype observed in SQT iPSC-CMs was effectively rescued by a short-peptide scorpion toxin BmKKx2 with a mechanism of targeting KCNH2. Conclusions: We demonstrate that patient-specific and gene-corrected iPSC-CMs are able to recapitulate single-cell phenotype of SQT, which is caused by the gain-of-function mutation KCNH2 T618I. These findings will help elucidate the mechanisms underlying SQT and discover therapeutic drugs for treating the disease by using peptide toxins as lead compounds.

Previous results have shown that hydrogen peroxide (H2O2) is involved in abscisic acid (ABA)-induced adventitious root development under drought stress. In this study, a comparative proteomic analysis was conducted to explore the key proteins during ABA-H2O2-induced adventitious rooting in cucumber (Cucumis sativus L.) under drought stress. The results revealed that 48 of 56 detected proteins spots were confidently matched to NCBI database entries. Among them, 10 protein spots were up-regulated while 4 protein spots were down-regulated under drought stress; 22 protein spots were up-regulated by ABA under drought stress; treatment with ABA plus H2O2 scavenger catalase (CAT) up-regulated 6 protein spots and down-regulated 6 protein spots under drought stress. The identified proteins were divided into three categories: biological process, molecular function, and cellular component. According to their functions, the 48 identified proteins were grouped into 10 categories, including photosynthesis, stress response, protein folding, modification, and degradation, etc. According to subcellular localization, about 24 proteins (half of the total) were predicted to be localized in chloroplasts. ABA significantly up-regulated the expression of photosynthesis-related proteins (SBPase, OEE1), stress-defense-related proteins (2-Cys-Prx, HBP2), and folding-, modification-, and degradation-related proteins (TPal) under drought stress. However, the effects of ABA were inhibited by CAT. The proteins were further analyzed at the transcription level, and the expression of four of five genes (except 2-Cys-Prx) was in accordance with the corresponding protein expression. The protein abundance changes of OEE1 and SBPase were also supported by western blot analysis. Therefore, H2O2 may be involved in ABA-induced adventitious root development under drought stress by regulating photosynthesis-related proteins, stress defense-related proteins, and folding-, modification-, and degradation-related proteins.

5-Aminolevulinic acid (ALA) is a common precursor of tetrapyrroles as well as a crucial growth regulator in higher plants. ALA has been proven to be effective in improving photosynthesis and alleviating the adverse effects of various abiotic stresses in higher plants. However, little is known about the mechanism of ALA in ameliorating the photosynthesis of plant under abiotic stress. In this paper, we studied the effects of exogenous ALA on salinity-induced damages of photosynthesis in cucumber (Cucumis sativus L.) seedlings. We found that the morphology (plant height, leave area), light utilization capacity of PS II [qL, Y(II)] and gas exchange capacity (Pn, gs, Ci, and Tr) were significantly retarded under NaCl stress, but these parameters were all recovered by the foliar application of 25 mg L-1 ALA. Besides, salinity caused heme accumulation and up-regulation of gene expression of ferrochelatase (HEMH) with suppression of other genes involved in chlorophyll synthesis pathway. Exogenously application of ALA under salinity down-regulated the heme content and HEMH expression, but increased the gene expression levels of glutamyl-tRNA reductase (HEMA1), Mg-chelatase (CHLH), and protochlorophyllide oxidoreductase (POR). Moreover, the contents of intermediates involved in chlorophyll branch were increased by ALA, including protoporphyrin IX (Proto IX), Mg-protoporphyrin IX (Mg-Proto IX, protochlorophyllide (Pchlide), and chlorophyll (Chl a and Chl b) under salt stress. Ultrastructural observation of mesophyll cell showed that the damages of photosynthetic apparatus under salinity were fixed by ALA. Collectively, the chlorophyll biosynthesis pathway was enhanced by exogenous ALA to improve the tolerance of cucumber under salinity.

Background— Cardiotoxicity is a leading cause for drug attrition during pharmaceutical development and has resulted in numerous preventable patient deaths. Incidents of adverse cardiac drug reactions are more common in patients with preexisting heart disease than the general population. Here we generated a library of human induced pluripotent stem cell–derived cardiomyocytes (hiPSC-CMs) from patients with various hereditary cardiac disorders to model differences in cardiac drug toxicity susceptibility for patients of different genetic backgrounds. Methods and Results— Action potential duration and drug-induced arrhythmia were measured at the single cell level in hiPSC-CMs derived from healthy subjects and patients with hereditary long QT syndrome, familial hypertrophic cardiomyopathy, and familial dilated cardiomyopathy. Disease phenotypes were verified in long QT syndrome, hypertrophic cardiomyopathy, and dilated cardiomyopathy hiPSC-CMs by immunostaining and single cell patch clamp. Human embryonic stem cell–derived cardiomyocytes (hESC-CMs) and the human ether-a-go-go –related gene expressing human embryonic kidney cells were used as controls. Single cell PCR confirmed expression of all cardiac ion channels in patient-specific hiPSC-CMs as well as hESC-CMs, but not in human embryonic kidney cells. Disease-specific hiPSC-CMs demonstrated increased susceptibility to known cardiotoxic drugs as measured by action potential duration and quantification of drug-induced arrhythmias such as early afterdepolarizations and delayed afterdepolarizations. Conclusions— We have recapitulated drug-induced cardiotoxicity profiles for healthy subjects, long QT syndrome, hypertrophic cardiomyopathy, and dilated cardiomyopathy patients at the single cell level for the first time. Our data indicate that healthy and diseased individuals exhibit different susceptibilities to cardiotoxic drugs and that use of disease-specific hiPSC-CMs may predict adverse drug responses more accurately than the standard human ether-a-go-go –related gene test or healthy control hiPSC-CM/hESC-CM screening assays.

Hydrogen gas (H2) was first identified as a unique molecular messenger in animals. Since H2 was reported as a novel antioxidant, it has been proven effective in treating many diseases. However, the studies concerning H2 in plants are just beginning to emerge. Here, two paths of H2 production in plants have been reported, namely, hydrogenase and nitrogenase. H2 has positive effects on seed germination, seedling growth, adventitious rooting, root elongation, harvest freshness, stomatal closure and anthocyanin synthesis. H2 also can enhance plant symbiotic stress resistance commonly through the enhancement of antioxidant defence system. Moreover, H2 shows cross talk with nitric oxide, carbon monoxide and other signalling molecules (for example, abscisic acid, ethylene and jasmonate acid). H2 can regulate the expression of responsive genes under abiotic stress and during adventitious roots formation and anthocyanin biosynthesis. Future work will need to focus on the molecular mechanism of H2 and its crosstalk with other signalling molecules in plants. With its promising application in agriculture, hydrogen agriculture will be welcomed in the near future.

Background— Drug-induced arrhythmia is one of the most common causes of drug development failure and withdrawal from market. This study tested whether human induced pluripotent stem cell–derived cardiomyocytes (hiPSC-CMs) combined with a low-impedance microelectrode array (MEA) system could improve on industry-standard preclinical cardiotoxicity screening methods, identify the effects of well-characterized drugs, and elucidate underlying risk factors for drug-induced arrhythmia. hiPSC-CMs may be advantageous over immortalized cell lines because they possess similar functional characteristics as primary human cardiomyocytes and can be generated in unlimited quantities. Methods and Results— Pharmacological responses of beating embryoid bodies exposed to a comprehensive panel of drugs at 65 to 95 days postinduction were determined. Responses of hiPSC-CMs to drugs were qualitatively and quantitatively consistent with the reported drug effects in literature. Torsadogenic hERG blockers, such as sotalol and quinidine, produced statistically and physiologically significant effects, consistent with patch-clamp studies, on human embryonic stem cell–derived cardiomyocytes hESC-CMs. False-negative and false-positive hERG blockers were identified accurately. Consistent with published studies using animal models, early afterdepolarizations and ectopic beats were observed in 33% and 40% of embryoid bodies treated with sotalol and quinidine, respectively, compared with negligible early afterdepolarizations and ectopic beats in untreated controls. Conclusions— We found that drug-induced arrhythmias can be recapitulated in hiPSC-CMs and documented with low impedance MEA. Our data indicate that the MEA/hiPSC-CM assay is a sensitive, robust, and efficient platform for testing drug effectiveness and for arrhythmia screening. This system may hold great potential for reducing drug development costs and may provide significant advantages over current industry standard assays that use immortalized cell lines or animal models.