The plant hormone abscisic acid (ABA) acts as a developmental signal and as an integrator of environmental cues such as drought and cold. Key players in ABA signal transduction include the type 2C protein phosphatases (PP2Cs) ABI1 and ABI2, which act by negatively regulating ABA responses. In this study, we identify interactors of ABI1 and ABI2 which we have named regulatory components of ABA receptor (RCARs). In Arabidopsis, RCARs belong to a family with 14 members that share structural similarity with class 10 pathogen-related proteins. RCAR1 was shown to bind ABA, to mediate ABA-dependent inactivation of ABI1 or ABI2 in vitro, and to antagonize PP2C action in planta. Other RCARs also mediated ABA-dependent regulation of ABI1 and ABI2, consistent with a combinatorial assembly of receptor complexes.

SUMMARYThe recent discovery of a variety of receptors has led to new models for hormone perception in plants. In the case of the hormone abscisic acid (ABA), which regulates plant responses to abiotic stress, perception seems to occur both at the plasma membrane and in the cytosol. The cytosolic receptors for ABA have recently been identified as complexes between protein phosphatases 2C (PP2C) and regulatory components (RCAR/PYR/ PYL) that bind ABA. Binding of ABA to the receptor complexes inactivates the PP2Cs, thereby activating the large variety of physiological processes regulated by ABA. The Arabidopsis genome encodes 13 homologues of RCAR1 and approximately 80 PP2Cs, of which six in clade A have been identified as negative regulators of ABA responses. In this study we characterize a novel member of the RCAR family, RCAR3. RCAR3 was identified in a screen for interactors of the PP2Cs ABI1 and ABI2, which are key regulators of ABA responses. RCAR3 was shown to repress ABI1 and ABI2 in vitro, and to stimulate ABA signalling in protoplast cells. RCAR3 conferred greater ABA sensitivity to the PP2C regulation than RCAR1, whereas stereo-selectivity for (S)-ABA was less stringent with RCAR3 as compared with RCAR1. In addition, regulation of the protein phosphatase activity by RCAR1 and RCAR3 was more sensitive to ABA for ABI1 than for ABI2. Based on the differences we have observed in transcriptional regulation and biochemical properties, we propose a model whereby differential expression of the co-receptors and combinatorial assembly of the receptor complexes act in concert to modulate and fine-tune ABA responses.

Pregnancy invokes a doubling of intestinal calcium absorption whereas lactation programs skeletal resorption to provide calcium to milk. Postweaning bone formation restores the skeleton's bone mineral content (BMC), but the factors that regulate this are not established. We used Pth-null mice to test whether parathyroid hormone (PTH) is required for postweaning skeletal recovery. On a normal 1% calcium diet, wild-type (WT) and Pth-null mice each gained BMC during pregnancy, declined 15% to 18% below baseline during lactation, and restored the skeleton above baseline BMC within 14 days postweaning. A 2% calcium diet reduced the lactational decline in BMC without altering the gains achieved during pregnancy and postweaning. The hypocalcemia and hyperphosphatemia of Pth-null mice normalized during lactation and serum calcium remained normal during postweaning. Osteocalcin and propeptide of type 1 collagen (P1NP) each rose significantly after lactation to similar values in WT and Pth-null. Serum calcitriol increased fivefold during pregnancy in both genotypes whereas vitamin D binding protein levels were unchanged. Absence of PTH blocked a normal rise in fibroblast growth factor-23 (FGF23) during pregnancy despite high calcitriol. A 30-fold higher expression of Cyp27b1 in maternal kidneys versus placenta suggests that the pregnancy-related increase in calcitriol comes from the kidneys. Conversely, substantial placental expression of Cyp24a1 may contribute significantly to the metabolism of calcitriol. In conclusion, PTH is not required to upregulate renal expression of Cyp27b1 during pregnancy or to stimulate recovery from loss of BMC caused by lactation. A calcium-rich diet in rodents suppresses skeletal losses during lactation, unlike clinical trials that showed no effect of supplemental calcium on lactational decline in BMC.

Tendons that connect muscles to bone are often the targets of sports injuries. The currently unsatisfactory state of tendon repair is largely attributable to the limited understanding of basic tendon biology. A number of tendon lineage-related transcription factors have recently been uncovered and provide clues for the better understanding of tendon development. Scleraxis and Mohawk have been identified as critical transcription factors in tendon development and differentiation. Other transcription factors, such as Sox9 and Egr1/2, have also been recently reported to be involved in tendon development. However, the molecular mechanisms and application of these transcription factors remain largely unclear and this prohibits their use in tendon therapy. Here, we systematically review and analyze recent findings and our own data concerning tendon transcription factors and tendon regeneration. Based on these findings, we provide interaction and temporal programming maps of transcription factors, as a basis for future tendon therapy. Finally, we discuss future directions for tendon regeneration with differentiation and trans-differentiation approaches based on transcription factors.

Background: Prehypertension is a category between normotension and hypertension that is becoming increasingly common in China. However, limited data are available on the prevalence and correlates of prehypertension in northeastern China. Methods: A cross-sectional study using stratified, clustered multistage, and random sampling methods was performed on 17,584 participants. Results: The prevalence of prehypertension and hypertension was 36.0% and 30.8% in northeastern China, respectively. As age increased, the prevalence of prehypertension in males declined (p-trend < 0.001), in parallel to an increase in the prevalence of hypertension (p-trend < 0.001). The prevalence of hypertension for females increased as age increased (p-trend < 0.001). Logistic regression analysis showed that age, gender, location, drinking, Body Mass Index (BMI), abdominal obesity, hypertriglyceridemia, and hypercholesterolemia correlated with prehypertension and hypertension (p-trend < 0.05). Conclusions: This study revealed a high prevalence of prehypertension and hypertension in an adult population of northeastern China and some correlates of prehypertension and hypertension.

BackgroundAntipsychotics have serious metabolic side effects on blood glucose. However, the comparative influence of these drugs on blood glucose levels has not been comprehensively evaluated. We conducted a network meta-analysis to create a hierarchy of the side effects of 12 antipsychotic drugs on changes in blood glucose levels.MethodsA systematic search of the PubMed, EMBASE and Cochrane databases (last search June 2016) was conducted to identify studies that reported randomized controlled trials (RCTs) comparing changes in blood glucose levels between patients receiving one of 12 antipsychotic drugs or a placebo for the treatment of schizophrenia or related disorders. The studies we searched were limited to those published in English. Two reviewers independently extracted data. The primary outcome of interest was changes in fasting glucose levels.ResultsWe included 47 studies with 114 relevant arms. Of the antipsychotic drugs, only olanzapine was associated with significantly increased glucose levels compared to a placebo (mean difference (MD) = 3.95, 95% confidence interval (CI) = 0.14 to 7.76). Moreover, olanzapine was associated with a significantly greater change in the glucose levels than ziprasidone (MD = 5.51, 95% CI = 1.62 to 9.39), lurasidone (MD = 5.58, 95% CI = 0.53 to 10.64) or risperidone (MD = 3.05, 95% CI = 0.87 to 5.22). Ziprasidone and lurasidone were associated with minimal glucose changes compared to the other antipsychotics.ConclusionsOlanzapine was associated with a significantly greater change in blood glucose levels than ziprasidone, lurasidone, risperidone or placebo treatment. The application of a hierarchy of glucose metabolism-related side effects may help clinicians tailor the choice of antipsychotic drug to meet the needs of individual patients.Electronic supplementary materialThe online version of this article (10.1186/s12888-017-1539-0) contains supplementary material, which is available to authorized users.

HighlightsEpidemiologic evidence on the potential role of ambient air pollution in MAFLD is limited.This study found significant positive associations between air pollution and the odds of MAFLD.Unhealthy lifestyle habits and the presence of central obesity may exacerbate the harmful effects.This large-scale human study provides robust results and calls for more prospective studies.

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