Investigating the Molecular Mechanisms of Renal Hepcidin Induction and Protection upon Hemoglobin-Induced Acute Kidney Injury

Hemolysis is known to cause acute kidney injury (AKI). The iron regulatory hormone hepcidin, produced by renal distal tubules, is suggested to exert a renoprotective role during this pathology. We aimed to elucidate the molecular mechanisms of renal hepcidin synthesis and its protection against hemoglobin-induced AKI. In contrast to known hepatic hepcidin induction, incubation of mouse cortical collecting duct (mCCD_cl1) cells with IL-6 or LPS did not induce Hamp1 mRNA expression, whereas iron (FeS) and hemin significantly induced hepcidin synthesis (p < 0.05). Moreover, iron/heme-mediated hepcidin induction in mCCD_cl1 cells was caused by the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway, as indicated by increased nuclear Nrf2 translocation and induced expression of Nrf2 downstream targets GCLM (p < 0.001), NQO1 (p < 0.001), and TXNRD1 (p < 0.005), which could be prevented by the known Nrf2 inhibitor trigonelline. Newly created inducible kidney-specific hepcidin KO mice demonstrated a significant reduction in renal Hamp1 mRNA expression. Phenylhydrazine (PHZ)-induced hemolysis caused renal iron loading and oxidative stress in both wildtype (Wt) and KO mice. PHZ treatment in Wt induced inflammatory markers (IL-6, TNFα) but not Hamp1. However, since PHZ treatment also significantly reduced systemic hepcidin levels in both Wt and KO mice (both p < 0.001), a dissection between the roles of systemic and renal hepcidin could not be made. Combined, the results of our study indicate that there are kidney-specific mechanisms in hepcidin regulation, as indicated by the dominant role of iron and not inflammation as an inducer of renal hepcidin, but also emphasize the complex interplay of various iron regulatory mechanisms during AKI on a local and systemic level.     

A matheuristic approach for the minimum broadcast time problem using a biased random-key genetic algorithm

The Minimum Broadcast Time (MBT) is a well-known data dissemination problem whose goal is to find a broadcast scheme that minimizes the number of steps needed to execute the broadcast operation. The problem has many applications in distributed systems and, in particular, the Industry 4.0 domain. Because Industry 4.0 applications rely primarily on the use of large-scale machine to machine communications, they need data dissemination techniques that combine high reliability with low communication latency. This work proposes a Biased Random-Key Genetic Algorithm and a matheuristic for the MBT. We carry out experiments with our algorithms on instances commonly used in the literature (hypercube, shuffle exchange, cube-connected cycles, de Bruijn, Harary graphs), and also on massive synthetic instances (up to 1000 vertices), allowing to cover many possibilities of real industry topologies. Our proposal is also compared with state-of-the-art exact methods and heuristics. Experimental results show that our algorithm is able to outperform the best-known heuristics for the MBT, and also that it is a very good alternative for large instances that cannot be solved by current exact methods.     

1,2-二硬脂酰基-sn-甘油-3-磷脂酰丝氨酸的全合成

(S)-2-[(苄氧羰基)氨基]-3-羟基丙酸苄酯（Ⅰ）经亚磷酸二苯酯处理得到了(S)-2-[(苄氧羰基)氨基]-2-(苄氧羰基)乙基膦酸酯（Ⅱ）；化合物Ⅱ经新戊酰氯介导活化后，与(S)-(+)-2,2-二甲基-1,3-二氧戊环-4-甲醇（Ⅲ）缩合，并由碘氧化得到新化合物(R)-2,3-异亚丙基-sn-甘油基{(S)-2-[(苄氧羰基)氨基]-2-(苄氧羰基)-1-氧乙基}膦酸酯（Ⅳ）；然后，化合物Ⅳ在三氟乙酸的作用下脱除异丙叉基得到(R)-2,3-二羟基丙基-sn-甘油基{(S)-2-[(苄氧羰基)氨基]-2-(苄氧羰基)-1-氧乙基}膦酸酯（Ⅴ）；在1-乙基-(3-二甲氨基丙基)碳酰二亚胺盐酸盐（EDCI）的作用下，中间体Ⅴ与硬脂酸进一步乙酰化，以85.8%的产率得到了(R)-2,3-双(硬脂酰基)丙酰基{(S)-2-[(苄氧羰基)氨基]-2-(苄氧羰基)-1-氧乙基}膦酸酯（Ⅵ）；中间体Ⅵ经氢解得到了1,2-二硬脂酰基-sn-甘油-3-磷脂酰丝氨酸（Ⅶ）。对主要合成步骤的反应条件进行了优化，并进行了验证和放大实验。产物Ⅶ共经历5步反应，总产率为57.1%。采用FTIR、HRMS和...