Participation of lipopolysaccharide in hyperplasic adipose expansion: Involvement of NADPH oxidase/ROS/p42/p44 MAPK‐dependent Cyclooxygenase‐2

Obesity is a world‐wide problem, especially the child obesity, with the complication of various metabolic diseases. Child obesity can be developed as early as the age between 2 and 6. The expansion of fat mass in child age includes both hyperplasia and hypertrophy of adipose tissue, suggesting the importance of proliferation and adipogenesis of preadipocytes. The changed composition of gut microbiota is associated with obesity, revealing the roles of lipopolysaccharide (LPS) on manipulating adipose tissue development. Studies suggest that LPS enters the circulation and acts as a pro‐inflammatory regulator to facilitate pathologies. Nevertheless, the underlying mechanisms behind LPS‐modulated obesity are yet clearly elucidated. This study showed that LPS enhanced the expression of cyclooxygenase‐2 (COX‐2), an inflammatory regulator of obesity, in preadipocytes. Pretreating preadipocytes with the scavenger of reactive oxygen species (ROS) or the inhibitors of NADPH oxidase or p42/p44 MAPK markedly decreased LPS‐stimulated gene expression of COX‐2 together with the phosphorylation of p47^phox and p42/p44 MAPK, separately. LPS activated p42/p44 MAPK via NADPH oxidase‐dependent ROS accumulation in preadipocytes. Reduction of intracellular ROS or attenuation of p42/p44 MAPK activation both reduced LPS‐mediated COX‐2 expression and preadipocyte proliferation. Moreover, LPS‐induced preadipocyte proliferation and adipogenesis were abolished by the inhibition of COX‐2 or PEG₂ receptors. Taken together, our results suggested that LPS enhanced the proliferation and adipogenesis of preadipocytes via NADPH oxidase/ROS/p42/p44 MAPK‐dependent COX‐2 expression.     

LGR5 regulates osteogenic differentiation of human thoracic ligamentum flavum cells by Wnt signalling pathway

Thoracic ossification of the ligamentum flavum (TOLF) is ectopic ossification of the spinal ligaments. Histologically, the development of TOLF can be described as the process of endochondral ossification. However, the underlying aetiology has not been completely clarified. In this investigation, the gene expression profile associated with leucine‐rich repeat‐containing G‐protein‐coupled receptors (LGR) and Wnt signalling pathway in the thoracic ligamentum flavum cells (TLFCs) of different ossification stages was analysed via RNA sequencing. We further confirmed the significant differences in the related gene expression profile by Gene Ontology (GO) enrichment analysis. LGR5 was first identified in primary human TLFCs during osteogenic differentiation. To evaluate the effect of LGR5 on osteogenic differentiation, LGR5 has been knocked down and overexpressed in human TLFCs. We observed that the knockdown of LGR5 inhibited the activity of Wnt signalling and attenuated the potential osteogenic differentiation of TLFCs, while overexpression of LGR5 activated the Wnt signalling pathway and increased osteogenic differentiation. Our results provide important evidence for the potent positive mediatory effects of LGR5 on osteogenesis by enhancing the Wnt signalling pathway in TOLF.     

Direct adenylation from 5′-OH-terminated oligonucleotides by a fusion enzyme containing Pfu RNA ligase and T4 polynucleotide kinase

5′-Adenylated oligonucleotides (AppOligos) are widely used for single-stranded DNA/RNA ligation in next-generation sequencing (NGS) applications such as microRNA (miRNA) profiling. The ligation between an AppOligo adapter and target molecules (such as miRNA) no longer requires ATP, thereby minimizing potential self-ligations and simplifying library preparation procedures. AppOligos can be produced by chemical synthesis or enzymatic modification. However, adenylation via chemical synthesis is inefficient and expensive, while enzymatic modification requires pre-phosphorylated substrate and additional purification. Here we cloned and characterized the Pfu RNA ligase encoded by the PF0353 gene in the hyperthermophilic archaea Pyrococcus furiosus. We further engineered fusion enzymes containing both Pfu RNA ligase and T4 polynucleotide kinase. One fusion enzyme, 8H-AP, was thermostable and can directly catalyze 5′-OH-terminated DNA substrates to adenylated products. The newly discovered Pfu RNA ligase and the engineered fusion enzyme may be useful tools for applications using AppOligos.     

RUS家族对植物生长发育的调控作用

叶绿体基因组编码许多参与光合作用和其他代谢过程的关键蛋白质,在叶绿体中合成的代谢物对于植物正常的生长发育至关重要。根对紫外线-B辐射敏感[Root-UVB (ultraviolet radiation B)-sensitive, RUS]蛋白属于叶绿体蛋白,由高度保守的DUF647结构域组成,在参与植物形态发生、物质运输和能量代谢等多种生命活动的调控中发挥作用。本文就近年来关于RUS家族在植物的胚胎发育、光形态建成、维生素B6稳态、生长素转运和花药发育等生长发育过程中的相关研究进行回顾和总结,为深入研究其在植物生长发育中的分子调控机制提供了参考。     

Epidemic management and control through risk-dependent individual contact interventions

Testing, contact tracing, and isolation (TTI) is an epidemic management and control approach that is difficult to implement at scale because it relies on manual tracing of contacts. Exposure notification apps have been developed to digitally scale up TTI by harnessing contact data obtained from mobile devices; however, exposure notification apps provide users only with limited binary information when they have been directly exposed to a known infection source. Here we demonstrate a scalable improvement to TTI and exposure notification apps that uses data assimilation (DA) on a contact network. Network DA exploits diverse sources of health data together with the proximity data from mobile devices that exposure notification apps rely upon. It provides users with continuously assessed individual risks of exposure and infection, which can form the basis for targeting individual contact interventions. Simulations of the early COVID-19 epidemic in New York City are used to establish proof-of-concept. In the simulations, network DA identifies up to a factor 2 more infections than contact tracing when both harness the same contact data and diagnostic test data. This remains true even when only a relatively small fraction of the population uses network DA. When a sufficiently large fraction of the population (≳ 75%) uses network DA and complies with individual contact interventions, targeting contact interventions with network DA reduces deaths by up to a factor 4 relative to TTI. Network DA can be implemented by expanding the computational backend of existing exposure notification apps, thus greatly enhancing their capabilities. Implemented at scale, it has the potential to precisely and effectively control future epidemics while minimizing economic disruption.