Dynamic changes in butyrate levels regulate satellite cell homeostasis by preventing spontaneous activation during aging

The gut microbiota plays a pivotal role in systemic metabolic processes and in particular functions,such as developing and preserving the skeletal muscle system.However,the interplay between gut microbiota/metabolites and the regulation of satellite cell(SC)homeostasis,particularly during aging,remains elusive.We propose that gut microbiota and its metabolites modulate SC physiology and homeostasis throughout skeletal muscle development,regeneration,and aging process.Our investigation reveals that microbial dysbiosis manipulated by either antibiotic treatment or fecal microbiota transplantation from aged to adult mice,leads to the activation of SCs or a significant reduction in the total number.Furthermore,employing multi-omics(e.g.,RNA-seq,16S r RNA gene sequencing,and metabolomics)and bioinformatic analysis,we demonstrate that the reduced butyrate levels,alongside the gut microbial dysbiosis,could be the primary factor contributing to the reduction in the number of SCs and subsequent impairments during skeletal muscle aging.Meanwhile,butyrate supplementation can mitigate the antibiotics-induced SC activation irrespective of gut microbiota,potentially by inhibiting the proliferation and differentiation of SCs/myoblasts.The butyrate effect is likely facilitated through the monocarboxylate transporter 1(Mct1),a lactate transporter enriched on membranes of SCs and myoblasts.As a result,butyrate could serve as an alternative strategy to enhance SC homeostasis and function during skeletal muscle aging.Our findings shed light on the potential application of microbial metabolites in maintaining SC homeostasis and preventing skeletal muscle aging.

Gut microbiota bridges the iron homeostasis and host health

The gut microbiota acts as a symbiotic microecosystem that plays an indispensable role in the regulation of a number of metabolic processes in the host by secreting secondary metabolites and impacting the physiology and pathophysiology of numerous organs and tissues through the circulatory system. This relationship, referred to as the “gut-X axis”, is associated with the development and progression of disorders, including obesity, fatty liver and Parkinson's disease. Given its importance, the gut flora is a vital research area for the understanding and development of the novel therapeutic approaches for multiple disorders. Iron is a common but necessary element required by both mammals and bacteria. As a result, iron metabolism is closely intertwined with the gut microbiota. The host's iron homeostasis affects the composition of the gut microbiota and the interaction between host and gut microbiota through various mechanisms such as nutrient homeostasis, intestinal peaceability,gut immunity, and oxidative stress. Therefore, understanding the relationship between gut microbes and host iron metabolism is not only of enormous significance to host health but also may offer preventative and therapeutic approaches for a number of disorders that impact both parties. In this review, we delve into the connection between the dysregulation of iron metabolism and dysbiosis of gut microbiota, and how it contributes to the onset and progression of metabolic and chronic diseases.

Vulnerable Point Identification Using Heterogeneous Interdependent Node Theory for Distribution Systems

In order to reduce the occurrence or expansion of accidents and maintain safety in distribution networks,it is essential to find out the vulnerable points for the power system in time.In this paper,a vulnerable point identification method based on heterogeneous interdependent(HI)node theory and risk theory is proposed.Compared with the methods based on betweenness theory,the method based on HI nodes theory can deal with the shortcomings of the power flow shortest path,and consider the direct and indirect relationship of nodes.It is more suitable for identifying vulnerable points in a realistic power system.First,according to the analysis of heterogenous interdependent networks,the HI nodes are defined and used to evaluate the utility coupling value of each node.Then an identification indicator,which combines the utility coupling value and the risk indicators,is utilized to evaluate the vulnerability of each node.Results show that the proposed method is a suitable one to find the vulnerable points and better than betweennessbased methods for a distribution network.

Performance evaluation of multi-GNSSs navigation in super synchronous transfer orbit and geostationary earth orbit

The autonomous navigation of the spacecrafts in High Elliptic Orbit (HEO), Geostationary Earth Orbit (GEO) and Geostationary Transfer Orbit (GTO) based on Global Navigation Satellite System (GNSS) are considered feasible in many studies. With the completion of BeiDou Navigation Satellite System with Global Coverage (BDS-3) in 2020, there are at least 130 satellites providing Position, Navigation, and Timing (PNT) services. In this paper, considering the latest CZ-5(Y3) launch scenario of Shijian-20 GEO spacecraft via Super-Synchronous Transfer Orbit (SSTO) in December 2019, the navigation performance based on the latest BeiDou Navigation Satellite System (BDS), Global Positioning System (GPS), Galileo Navigation Satellite System (Galileo) and GLObal NAvigation Satellite System (GLONASS) satellites in 2020 is evaluated, including the number of visible satellites, carrier to noise ratio, Doppler, and Position Dilution of Precision (PDOP). The simulation results show that the GEO/Inclined Geo-Synchronous Orbit (IGSO) navigation satellites of BDS-3 can effectively increase the number of visible satellites and improve the PDOP in the whole launch process of a typical GEO spacecraft, including SSTO and GEO, especially for the GEO spacecraft on the opposite side of Asia-Pacific region. The navigation performance of high orbit spacecrafts based on multi-GNSSs can be significantly improved by the employment of BDS-3. This provides a feasible solution for autonomous navigation of various high orbit spacecrafts, such as SSTO, MEO, GEO, and even Lunar Transfer Orbit (LTO) for the lunar exploration mission.

Gut microbiota in muscular atrophy development,progression,and treatment:New therapeutic targets and opportunities

Skeletal muscle atrophy is a debilitating condition that significantly affects quality of life and often lacks effective treatment options.Muscle atrophy can have various causes,including myogenic,neurogenic,and other factors.Recent investigation has underscored a compelling link between the gut microbiota and skeletal muscle.Discerning the potential differences in the gut microbiota associated with muscle atrophy-related diseases,understanding their influence on disease development,and recognizing their potential as intervention targets are of paramount importance.This review aims to provide a comprehensive overview of the role of the gut microbiota in muscle atrophy-related diseases.We summarize clinical and pre-clinical studies that investigate the potential for gut microbiota modulation to enhance muscle performance and promote disease recovery.Furthermore,we delve into the intricate interplay between the gut microbiota and muscle atrophy-related diseases,drawing from an array of studies.Emerging evidence suggests significant differences in gut microbiota composition in individuals with muscle atrophy-related diseases compared with healthy individuals.It is conceivable that these alterations in the microbiota contribute to the pathogenesis of these disorders through bacterium-related metabolites or inflammatory signals.