Muscle-bone cross-talk through the FNIP1-TFEB-IGF2 axis is associated with bone metabolism in human and mouse.

Clinical evidence indicates a close association between muscle dysfunction and bone loss; however, the underlying mechanisms remain unclear. Here, we report that muscle dysfunction-related bone loss in humans with limb-girdle muscular dystrophy is associated with decreased expression of folliculin-interacting protein 1 (FNIP1) in muscle tissue. Supporting this finding, murine gain- and loss-of-function genetic models demonstrated that muscle-specific ablation of FNIP1 caused decreased bone mass, increased osteoclastic activity, and mechanical impairment that could be rescued by myofiber-specific expression of FNIP1. Myofiber-specific FNIP1 deficiency stimulated expression of nuclear translocation of transcription factor EB, thereby activating transcription of insulin-like growth factor 2 (Igf2) at a conserved promoter-binding site and subsequent IGF2 secretion. Muscle-derived IGF2 stimulated osteoclastogenesis through IGF2 receptor signaling. AAV9-mediated overexpression of IGF2 was sufficient to decrease bone volume and impair bone mechanical properties in mice. Further, we found that serum IGF2 concentration was negatively correlated with bone health in humans in the context of osteoporosis. Our findings elucidate a muscle-bone cross-talk mechanism bridging the gap between muscle dysfunction and bone loss. This cross-talk represents a potential target to treat musculoskeletal diseases and osteoporosis.

AMPK phosphorylation of FNIP1 (S220) controls mitochondrial function and muscle fuel utilization during exercise.

Exercise-induced activation of adenosine monophosphate-activated protein kinase (AMPK) and substrate phosphorylation modulate the metabolic capacity of mitochondria in skeletal muscle. However, the key effector(s) of AMPK and the regulatory mechanisms remain unclear. Here, we showed that AMPK phosphorylation of the folliculin interacting protein 1 (FNIP1) serine-220 (S220) controls mitochondrial function and muscle fuel utilization during exercise. Loss of FNIP1 in skeletal muscle resulted in increased mitochondrial content and augmented metabolic capacity, leading to enhanced exercise endurance in mice. Using skeletal muscle-specific nonphosphorylatable FNIP1 (S220A) and phosphomimic (S220D) transgenic mouse models as well as biochemical analysis in primary skeletal muscle cells, we demonstrated that exercise-induced FNIP1 (S220) phosphorylation by AMPK in muscle regulates mitochondrial electron transfer chain complex assembly, fuel utilization, and exercise performance without affecting mechanistic target of rapamycin complex 1-transcription factor EB signaling. Therefore, FNIP1 is a multifunctional AMPK effector for mitochondrial adaptation to exercise, implicating a mechanism for exercise tolerance in health and disease.

FNIP1 abrogation promotes functional revascularization of ischemic skeletal muscle by driving macrophage recruitment.

Ischaemia of the heart and limbs attributable to compromised blood supply is a major cause of mortality and morbidity. The mechanisms of functional angiogenesis remain poorly understood, however. Here we show that FNIP1 plays a critical role in controlling skeletal muscle functional angiogenesis, a process pivotal for muscle revascularization during ischemia. Muscle FNIP1 expression is down-regulated by exercise. Genetic overexpression of FNIP1 in myofiber causes limited angiogenesis in mice, whereas its myofiber-specific ablation markedly promotes the formation of functional blood vessels. Interestingly, the increased muscle angiogenesis is independent of AMPK but due to enhanced macrophage recruitment in FNIP1-depleted muscles. Mechanistically, myofiber FNIP1 deficiency induces PGC-1α to activate chemokine gene transcription, thereby driving macrophage recruitment and muscle angiogenesis program. Furthermore, in a mouse hindlimb ischemia model of peripheral artery disease, the loss of myofiber FNIP1 significantly improved the recovery of blood flow. Thus, these results reveal a pivotal role of FNIP1 as a negative regulator of functional angiogenesis in muscle, offering insight into potential therapeutic strategies for ischemic diseases.

Comparative analyses of Linderniaceae plastomes, with implications for its phylogeny and evolution.

Introduction: The recently established Linderniaceae, separated from the traditionally defined Scrophulariaceae, is a taxonomically complicated family. Although previous phylogenetic studies based on a few short DNA markers have made great contributions to the taxonomy of Linderniaceae, limited sampling and low resolution of the phylogenetic tree have failed to resolve controversies between some generic circumscriptions. The plastid genome exhibits a powerful ability to solve phylogenetic relationships ranging from shallow to deep taxonomic levels. To date, no plastid phylogenomic studies have been carried out in Linderniaceae. Methods: In this study, we newly sequenced 26 plastid genomes of Linderniaceae, including eight genera and 25 species, to explore the phylogenetic relationships and genome evolution of the family through plastid phylogenomic and comparative genomic analyses. Results: The plastid genome size of Linderniaceae ranged from 152,386 bp to 154,402 bp, exhibiting a typical quartile structure. All plastomes encoded 114 unique genes, comprising 80 protein-coding genes, 30 tRNA genes, and four rRNA genes. The inverted repeat regions were more conserved compared with the single-copy regions. A total of 1803 microsatellites and 1909 long sequence repeats were identified, and five hypervariable regions (petN-psbM, rps16-trnQ, rpl32-trnL, rpl32, and ycf1) were screened out. Most protein-coding genes were relatively conserved, with only the ycf2 gene found under positive selection in a few species. Phylogenomic analyses confirmed that Linderniaceae was a distinctive lineage and revealed that the presently circumscribed Vandellia and Torenia were non-monophyletic. Discussion: Comparative analyses showed the Linderniaceae plastomes were highly conservative in terms of structure, gene order, and gene content. Combining morphological and molecular evidence, we supported the newly established Yamazakia separating from Vandellia and the monotypic Picria as a separate genus. These findings provide further evidence to recognize the phylogenetic relationships among Linderniaceae and new insights into the evolution of the plastid genomes.

CD93 Ameliorates Diabetic Wounds by Promoting Angiogenesis via the p38MAPK/MK2/HSP27 Axis.

OBJECTIVE: Diabetic wounds are a complication of diabetes mellitus, which is characterised by microcirculation dysfunction caused by decreased local blood supply and insufficient metabolic exchange. Clinically, in addition to glycaemic control, the most important treatment for diabetic wounds is to promote local angiogenesis, which accelerates wound healing. The authors previous study demonstrated that CD93, which is specifically expressed on vascular endothelial cells (ECs), redundantly regulates angiogenesis in zebrafish, suggesting that CD93 is a potential angiogenic molecule. However, the role of CD93 in diabetic wounds has not yet been elucidated. METHODS: The angiogenic effects of CD93 were studied from four aspects: exogenous, endogenous, in vitro, and in vivo. CD93 recombinant protein was used in microvascular ECs and in mice to observe angiogenesis in vitro and in vivo. The wound model was established in CD93-/- and wild type diabetic mice, and the degree of wound healing as well as the amount and maturity of neovascularisation were investigated. The possible mechanism of CD93 in angiogenesis was determined by CD93 overexpression in cultured ECs. RESULTS: CD93 recombinant protein was found to exogenously promote tube formation and sprouting of ECs. It also recruited cells to promote the formation of vascular like structures in subcutaneous tissue and accelerated wound healing by optimising angiogenesis and re-epithelisation. Furthermore, CD93 deficiency was observed to delay wound repair, characterised by reduced neovascularisation, vascular maturity, and re-epithelisation level. Mechanically, CD93 activated the p38MAPK/MK2/HSP27 signalling pathway, positively affecting the angiogenic functions of ECs. CONCLUSION: This study demonstrated that CD93 promotes angiogenesis both in vitro and in vivo and that its angiogenic role in vitro is mediated by the p38MAPK/MK2/HSP27 signalling pathway. It was also found that CD93 exerts beneficial effects on wound healing in diabetic mice by promoting angiogenesis and re-epithelisation.

Mitochondrial proteostasis stress in muscle drives a long-range protective response to alleviate dietary obesity independently of ATF4.

Mitochondrial quality in skeletal muscle is crucial for maintaining energy homeostasis during metabolic stresses. However, how muscle mitochondrial quality is controlled and its physiological impacts remain unclear. Here, we demonstrate that mitoprotease LONP1 is essential for preserving muscle mitochondrial proteostasis and systemic metabolic homeostasis. Skeletal muscle-specific deletion of Lon protease homolog, mitochondrial (LONP1) impaired mitochondrial protein turnover, leading to muscle mitochondrial proteostasis stress. A benefit of this adaptive response was the complete resistance to diet-induced obesity. These favorable metabolic phenotypes were recapitulated in mice overexpressing LONP1 substrate ΔOTC in muscle mitochondria. Mechanistically, mitochondrial proteostasis imbalance elicits an unfolded protein response (UPRmt) in muscle that acts distally to modulate adipose tissue and liver metabolism. Unexpectedly, contrary to its previously proposed role, ATF4 is dispensable for the long-range protective response of skeletal muscle. Thus, these findings reveal a pivotal role of LONP1-dependent mitochondrial proteostasis in directing muscle UPRmt to regulate systemic metabolism.

FNIP1 regulates adipocyte browning and systemic glucose homeostasis in mice by shaping intracellular calcium dynamics.

Metabolically beneficial beige adipocytes offer tremendous potential to combat metabolic diseases. The folliculin interacting protein 1 (FNIP1) is implicated in controlling cellular metabolism via AMPK and mTORC1. However, whether and how FNIP1 regulates adipocyte browning is unclear. Here, we demonstrate that FNIP1 plays a critical role in controlling adipocyte browning and systemic glucose homeostasis. Adipocyte-specific ablation of FNIP1 promotes a broad thermogenic remodeling of adipocytes, including increased UCP1 levels, high mitochondrial content, and augmented capacity for mitochondrial respiration. Mechanistically, FNIP1 binds to and promotes the activity of SERCA, a main Ca2+ pump responsible for cytosolic Ca2+ removal. Loss of FNIP1 resulted in enhanced intracellular Ca2+ signals and consequential activation of Ca2+-dependent thermogenic program in adipocytes. Furthermore, mice lacking adipocyte FNIP1 were protected against high-fat diet-induced insulin resistance and liver steatosis. Thus, these findings reveal a pivotal role of FNIP1 as a negative regulator of beige adipocyte thermogenesis and unravel an intriguing functional link between intracellular Ca2+ dynamics and adipocyte browning.

Disuse-associated loss of the protease LONP1 in muscle impairs mitochondrial function and causes reduced skeletal muscle mass and strength.

Mitochondrial proteolysis is an evolutionarily conserved quality-control mechanism to maintain proper mitochondrial integrity and function. However, the physiological relevance of stress-induced impaired mitochondrial protein quality remains unclear. Here, we demonstrate that LONP1, a major mitochondrial protease resides in the matrix, plays a role in controlling mitochondrial function as well as skeletal muscle mass and strength in response to muscle disuse. In humans and mice, disuse-related muscle loss is associated with decreased mitochondrial LONP1 protein. Skeletal muscle-specific ablation of LONP1 in mice resulted in impaired mitochondrial protein turnover, leading to mitochondrial dysfunction. This caused reduced muscle fiber size and strength. Mechanistically, aberrant accumulation of mitochondrial-retained protein in muscle upon loss of LONP1 induces the activation of autophagy-lysosome degradation program of muscle loss. Overexpressing a mitochondrial-retained mutant ornithine transcarbamylase (ΔOTC), a known protein degraded by LONP1, in skeletal muscle induces mitochondrial dysfunction, autophagy activation, and cause muscle loss and weakness. Thus, these findings reveal a role of LONP1-dependent mitochondrial protein quality-control in safeguarding mitochondrial function and preserving skeletal muscle mass and strength, and unravel a link between mitochondrial protein quality and muscle mass maintenance during muscle disuse.

Effect of Streptococcus anginosus on biological response of tongue squamous cell carcinoma cells.

BACKGROUND: Streptococcus anginosus (S. anginosus) was reported increased in oral squamous cell carcinoma (OSCC) tissue. The aim of this study was to investigate the response of oral cancer cells in the biological characteristics evoked by the S. anginosus and investigate its potential mechanisms. METHODS: The growth curve and concentration standard curve of S. anginosus were determined, and a series of concentrations of S. anginosus supernatant were applied to OSCC cell lines SCC15, then selected an optimal time and concentration by CCK-8 assay. Then autophagic response, proliferative activity, cell cycle and apoptosis, invasion and migration abilities were evaluated in SCC15. RESULTS: The results showed that when the ratio of S. anginosus supernatant to cell culture medium was 1:1 and the co-culture time was 16 h, the inhibitory effect on SCC15 was the most obvious; Furthermore, the supernatant of Streptococcus upregulated the autophagy activity of SCC15, thus significantly inhibiting its proliferation, migration and invasion ability. Compared with control groups, the cell cycle showed G1 arrest, S and G2/M phases decreased, and the percentage of apoptotic cells relatively increased (P < 0.05). CONCLUSION: S. anginosus reduced the proliferation, migration and invasion of SCC15 cells and promoted cell apoptosis; Moreover, autophagy may be one of the mechanisms in this process.

The complete chloroplast genome sequence of Juniperus saltuaria (Cupressaceae).

In order to supply genetic information of Juniperus saltuaria, we reported the complete chloroplast genome sequence based on high-throughput sequencing data. The whole chloroplast genome was 128,099 bp long with an asymmetric base composition (32.9% A, 16.9% C, 18.1% G and 32.1% T). The genome annotation predicted a total of 116 genes, including 82 protein-coding genes, 30 tRNA genes, and 4 rRNA genes. The neighbor-joining phylogenetic analysis based on 45 complete chloroplast genome sequences showed that J. saltuaria was more closely related to the congeneric J. recurva. The assembled chloroplast genome of J. saltuaria will provide useful genomic data both for the phylogenetic research of Juniperus and the conservation of this species.

The ethylene receptor regulates Typha angustifolia leaf aerenchyma morphogenesis and cell fate.

MAIN CONCLUSION: Ethylene receptor is crucial for PCD and aerenchyma formation in Typha angustifolia leaves. Not only does it receive and deliver the ethylene signal, but it probably can determine the cell fate during aerenchyma morphogenesis, which is due to the receptor expression quantity. Aquatic plant oxygen delivery relies on aerenchyma, which is formed by a programmed cell death (PCD) procedure. However, cells in the outer edge of the aerenchyma (palisade cells and septum cells) remain intact, and the mechanism is unclear. Here, we offer a hypothesis: cells that have a higher content of ethylene receptors do not undergo PCD. In this study, we investigated the leaf aerenchyma of the aquatic plant Typha angustifolia. Ethephon and pyrazinamide (PZA, an inhibitor of ACC oxidase) were used to confirm that ethylene is an essential hormone for PCD of leaf aerenchyma cells in T. angustifolia. That the ethylene receptor was an indispensable factor in this PCD was confirmed by 1-MCP (an inhibitor of the ethylene receptor) treatment. Although PCD can be avoided by blocking the ethylene receptor, excessive ethylene receptors also protect cells from PCD. TaETR1, TaETR2 and TaEIN4 in the T. angustifolia leaf were detected by immunofluorescence (IF) using polyclonal antibodies. The result showed that the content of ethylene receptors in PCD-unsusceptible cells was 4-14 times higher than that one in PCD-susceptible cells, suggesting that PCD-susceptible cells undergo the PCD programme, while PCD-unsusceptible cells do not due to the content difference in the ethylene receptor in different cells. A higher level of ethylene receptor content makes the cells insensitive to ethylene, thereby avoiding cell death and degradation.

Air quality improvement and health benefit of PM2.5 reduction from the coal cap policy in the Beijing-Tianjin-Hebei (BTH) region, China.

Large amounts of air pollutants emitted from massive coal combustion result in the air quality deterioration and threaten public health in China. To improve air quality, the Chinese government released the coal cap policy to reduce coal consumption. So it is important and necessary to understand the possible environmental impact and relevant health benefits from the coal cap policy. The purpose of this paper is to quantify the air quality improvement and to evaluate the health benefits from the implementation of the coal cap policy, with the Beijing-Tianjin-Hebei (BTH) region as the study area. The results showed that the emissions of SO2, NOx, CO, VOCs, PM10, and PM2.5 could be reduced by 20-40% in the BTH region in 2020 and all pollutants from industrial boilers notably decreased. Under the coal cap policy, the PM2.5 concentration in the whole region would fall by 11.27%, and the total economic benefit from health impacts could achieve 26.61 (13.29 to 39.14) billion RMB (3.9 billion USD) in the BTH region in 2020, accounting for 0.43% (0.21 to 0.63%) of regional GDP in 2013. This study demonstrated the quantification of environmental effect and health benefit from the coal cap policy, which could be used for the complete cost-benefit analysis and provide the sufficient support for policy makers to implement the coal cap policy in the BTH region and other areas of China.

Prediction of reduction potential of pollutant emissions under the coal cap policy in BTH region, China.

The coal cap policy is one of the most important measures to address the severe air pollution in China. To quantify the impact of the coal cap policy on emissions reduction, we designed four scenarios to predict the effect of energy saving and pollutant emissions reduction from coal-fired stationary sources in the BTH (Beijing-Tianjin-Hebei) region from 2014 to 2030. The results demonstrated that the coal cap strategy would significantly affect energy consumption structure and result in 15% of energy savings in 2020 and 25% in 2030. Moreover, the reduction potential of main pollutants from stationary coal combustion sources would achieve 36-45% in 2020 and 60-79% in 2030 relative to BAU (Business As Usual). For the whole BTH region the BPE (Backward Productivity Elimination) scenario could get a better effect for SO2 and NOX than CES (Clean Energy Strategy) scenario, while the effect is opposite for CO and PM2.5, and similar for VOCs and PM10. For Beijing, there would be very significant reduction for all pollutants under the CES scenario. For Tianjin and Hebei, there is little difference in the pollutants reduction between the BPE and CES scenarios. Power plants and industrial boilers are major contributors under the BPE scenario, and emissions from the heating boilers and residential sources are greatly reduced under the CES scenario. The findings in this study are of considerable value for the policymakers to implementing the coal cap policy in BTH region and other Chinese cities.

[Relationship between dental caries and salivary proteome by electrospray ionization ion-trap tandem mass spectrometry in children aged 6 to 8 years].

OBJECTIVE: To explore the relationship between salivary proteome and dental caries and to promote the biomarker studies of dental caries susceptibility by comparing the salivary proteome of caries-active children and caries-free children with electrospray ionization ion-trap tandem mass spectrometry (ESI-MS/MS). METHODS: Ten caries-active children and ten caries-free children were sampled. The salivary proteome of the two groups was studied, and the differential protein between the two groups was analyzed by ESI-MS/MS after sodium dodecyl sulfate polyacrylamide gel electrophoresis, filter-aided sample preparation, and liquid chromatography. RESULTS: The concentration of salivary protein was higher in the caries-active group than in the caries-free group. The polypeptide counts of thecaries-active and caries-free groups were 602 and 481, which belonged to 286 and 227 proteins, respectively. The differential polypeptide count of the two groups was 361, and the differential protein count was 118. The detected proteins included matrix metalloproteinase-9 (MMP9), mucin-7 (MUC7), lactotransferrin (LTF), carbonic anhydrase 6 (CA6), azurocidin (AZU), and cold agglutinin. CONCLUSION: The total salivary protein was higher in the caries-active group than in the caries-free group. The preliminary detection of differential proteins (MMP9, MUC7, LTF, CA6, AZU, and cold agglutinin) may lay some foundation for biomarker research of dental caries susceptibility.