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Abstracts: As the ‘Green Revolution’ gene, SD1 (encoding GA20ox2), has been widely applied to improve yield in rice breeding. However, research on its transcriptional regulation is limited. Here, we identified a transcription factor OsbZIP01, which can suppress the expression of SD1 and regulate gibberellin (GA) biosynthesis in rice. Knockout mutants of OsbZIP01 exhibited increased plant height, while the over- expression lines showed a semi-dwarf phenotype and diminished germination rate. Furthermore, the semi-dwarf phenotype of OE-bZIP01, was caused by the reduced internode length, which was accompanied by a thin stem width. The predominant expression of OsbZIP01 was observed in leaves and sheaths. OsbZIP01 protein was localized in the nucleus and showed transcriptional repression activity. In addition, OsbZIP01 could directly bind to the promoter of the OsSD1 gene, and inhibit its transcription. The semi-dwarf phenotype of OE-bZIP01 could be rescued by exogenous GA3. Meanwhile, the bzip01 sd1 double mutant showed a shorter shoot length compared with the wild type, indicating that OsbZIP01 regulated plant growth mainly through the GA biosynthesis pathway. Collectively, OsbZIP01 negatively regulates GA biosynthesis by restraining SD1 transcription, thereby affecting plant growth and development.

A mechanized direct seeding of rice with less labor and water usage, has been widely adopted. However, this approach requires varieties that exhibit uniform seedling emergence. Mesocotyl elongation (ME) offers the main drive of fast emergence of rice seedlings from soils; nevertheless, its genetic basis remains unknown. Here, we identify a major rice quantitative trait locus Mesocotyl Elongation1 (qME1), an allele of the Green Revolution gene Semi‐Dwarf1 (SD1), encoding GA20‐oxidase for gibberellin (GA) biosynthesis. ME1 expression is strongly induced by soil depth and ethylene. When rice grains are direct‐seeded in soils, the ethylene core signaling factor OsEIL1 directly promotes ME1 transcription, accelerating bioactive GA biosynthesis. The GAs further degrade the DELLA protein SLENDER RICE 1 (SLR1), alleviating its inhibition of rice PHYTOCHROME‐INTERACTING FACTOR‐LIKE13 (OsPIL13) to activate the downstream expansion gene OsEXPA4 and ultimately promote rice seedling ME and emergence. The ancient traits of long mesocotyl and strong emergence ability in wild rice and landrace were gradually lost in company with the Green Revolution dwarf breeding process, and an elite ME1‐R allele (D349H) is found in some modern Geng varieties (long mesocotyl lengths) in northern China, which can be used in the direct seeding and dwarf breeding of Geng varieties. Furthermore, the ectopic and high expression of ME1 driven by mesocotyl‐specific promoters resulted in rice plants that could be direct‐seeded without obvious plant architecture or yield penalties. Collectively, we reveal the molecular mechanism of rice ME, and provide useful information for breeding new Green Revolution varieties with long mesocotyl suitable for direct‐seeding practice. [ABSTRACT FROM AUTHOR]

Background and Aims Macrophage-derived foam cells play a causal role during the pathogenesis of atherosclerosis. P2Y6 receptor (P2Y6R) highly expressed has been considered as a disease-causing factor in atherogenesis, but the detailed mechanism remains unknown. This study aims to explore P2Y6R in regulation of macrophage foaming, atherogenesis, and its downstream pathways. Furthermore, the present study sought to find a potent P2Y6R antagonist and investigate the feasibility of P2Y6R-targeting therapy for atherosclerosis. Methods The P2Y6R expression was examined in human atherosclerotic plaques and mouse artery. Atherosclerosis animal models were established in whole-body P2Y6R or macrophage-specific P2Y6R knockout mice to evaluate the role of P2Y6R. RNA sequencing, DNA pull-down experiments, and proteomic approaches were performed to investigate the downstream mechanisms. High-throughput Glide docking pipeline from repurposing drug library was performed to find potent P2Y6R antagonists. Results The P2Y6R deficiency alleviated atherogenesis characterized by decreasing plaque formation and lipid deposition of the aorta. Mechanically, deletion of macrophage P2Y6R significantly inhibited uptake of oxidized low-density lipoprotein through decreasing scavenger receptor A expression mediated by phospholipase Cβ/store-operated calcium entry pathways. More importantly, P2Y6R deficiency reduced the binding of scavenger receptor A to CALR, accompanied by dissociation of calreticulin and STIM1. Interestingly, thiamine pyrophosphate was found as a potent P2Y6R antagonist with excellent P2Y6R antagonistic activity and binding affinity, of which the pharmacodynamic effect and mechanism on atherosclerosis were verified. Conclusions Macrophage P2Y6R regulates phospholipase Cβ/store-operated calcium entry/calreticulin signalling pathway to increase scavenger receptor A protein level, thereby improving foam cell formation and atherosclerosis, indicating that the P2Y6R may be a potential therapeutic target for intervention of atherosclerotic diseases using P2Y6R antagonists including thiamine pyrophosphate. [ABSTRACT FROM AUTHOR]

Background and Aims: Macrophage-derived foam cells play a causal role during the pathogenesis of atherosclerosis. P2Y6 receptor (P2Y6R) highly expressed has been considered as a disease-causing factor in atherogenesis, but the detailed mechanism remains unknown. This study aims to explore P2Y6R in regulation of macrophage foaming, atherogenesis, and its downstream pathways. Furthermore, the present study sought to find a potent P2Y6R antagonist and investigate the feasibility of P2Y6R-targeting therapy for atherosclerosis., Methods: The P2Y6R expression was examined in human atherosclerotic plaques and mouse artery. Atherosclerosis animal models were established in whole-body P2Y6R or macrophage-specific P2Y6R knockout mice to evaluate the role of P2Y6R. RNA sequencing, DNA pull-down experiments, and proteomic approaches were performed to investigate the downstream mechanisms. High-throughput Glide docking pipeline from repurposing drug library was performed to find potent P2Y6R antagonists., Results: The P2Y6R deficiency alleviated atherogenesis characterized by decreasing plaque formation and lipid deposition of the aorta. Mechanically, deletion of macrophage P2Y6R significantly inhibited uptake of oxidized low-density lipoprotein through decreasing scavenger receptor A expression mediated by phospholipase Cβ/store-operated calcium entry pathways. More importantly, P2Y6R deficiency reduced the binding of scavenger receptor A to CALR, accompanied by dissociation of calreticulin and STIM1. Interestingly, thiamine pyrophosphate was found as a potent P2Y6R antagonist with excellent P2Y6R antagonistic activity and binding affinity, of which the pharmacodynamic effect and mechanism on atherosclerosis were verified., Conclusions: Macrophage P2Y6R regulates phospholipase Cβ/store-operated calcium entry/calreticulin signalling pathway to increase scavenger receptor A protein level, thereby improving foam cell formation and atherosclerosis, indicating that the P2Y6R may be a potential therapeutic target for intervention of atherosclerotic diseases using P2Y6R antagonists including thiamine pyrophosphate., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: The activation of P2Y 14 receptor (P2Y 14 R) promotes osteoclast formation and causes neuropathic pain, exhibiting possible link to osteoarthritis (OA). Given lack of P2Y 14 R antagonist, the present study aims to search a novel P2Y 14 R antagonist with low toxicity and high activity from natural products as a possible drug candidate in treatment of OA., Methods: The role of P2Y 14 R on OA was verified using P2Y 14 R knockout (KO) rats. Molecular docking virtual screening strategy and activity test in P2Y 14 R stably-expressed HEK293 cells were used to screen target compound from natural product library. The MM/GBSA free energy calculation/decomposition technique was used to determine the principal interaction mechanism. Next, the binding of target compound to P2Y 14 R was examined using cellular thermal shift assay and drug affinity responsive target stability test. Finally, the therapeutic effect of target compound was performed in monosodium iodoacetate (MIA)-induced OA mouse model. To verify whether the effect of target compound was attributed to P2Y 14 R, we establish the osteoarthritis model in P2Y 14 R KO mice to perform pharmacodynamic evaluation. Importantly, to investigate the potential mechanism by which target compound attenuate OA, expressions of the major transcription factors involved in osteoclast differentiation were detected by western blot, while markers of nerve damage in dorsal root ganglion (DRG) were evaluated by RT-qPCR and immunofluorescence techniques., Results: Deficiency of P2Y 14 R alleviated pain behavior and cartilage destruction in MIA-induced OA rats. 14 natural compounds were screened by Glide docking-based virtual screening, among which paederosidic acid exhibited the highest antagonistic activity to P2Y 14 R with IC 50 of 8.287 μM. As a bioactive component extracted from Paederia scandens, paederosidic acid directly interacted with P2Y 14 R to enhance the thermostability and decrease the protease sensitivity of target protein, which significantly inhibited receptor activator for nuclear factor-κB ligand (RANKL)-mediated osteoclastogenesis. More importantly, paederosidic acid suppressed osteoclast formation by downregulating expressions of NFAT2 and ATP6V0D2, as well as relieved neuropathic pain by decreasing expressions of CGRP, CSF1 and galanin in DRG., Conclusions: Paederosidic acid targeted P2Y 14 R to improve OA through alleviating osteoclast formation and neuropathic pain, which provided an available strategy for developing novel drug leads for treatment of OA., Competing Interests: Declaration of Competing Interest All the authors state that they have no interest conflicts for this work., (Copyright © 2023 Elsevier GmbH. All rights reserved.)