The Degradation of Aqueous Oxytetracycline by an O3/CaO2 System in the Presence of HCO3-: Performance, Mechanism, Degradation Pathways, and Toxicity Evaluation.

This research constructed a novel O3/CaO2/HCO3- system to degrade antibiotic oxytetracycline (OTC) in water. The results indicated that CaO2 and HCO3- addition could promote OTC degradation in an O3 system. There is an optimal dosage of CaO2 (0.05 g/L) and HCO3- (2.25 mmol/L) that promotes OTC degradation. After 30 min of treatment, approximately 91.5% of the OTC molecules were eliminated in the O3/CaO2/HCO3- system. A higher O3 concentration, alkaline condition, and lower OTC concentration were conducive to OTC decomposition. Active substances including ·OH, 1O2, ·O2-, and ·HCO3- play certain roles in OTC degradation. The production of ·OH followed the order: O3/CaO2/HCO3- > O3/CaO2 > O3. Compared to the sole O3 system, TOC and COD were easier to remove in the O3/CaO2/HCO3- system. Based on DFT and LC-MS, active species dominant in the degradation pathways of OTC were proposed. Then, an evaluation of the toxic changes in intermediates during OTC degradation was carried out. The feasibility of O3/CaO2/HCO3- for the treatment of other substances, such as bisphenol A, tetracycline, and actual wastewater, was investigated. Finally, the energy efficiency of the O3/CaO2/HCO3- system was calculated and compared with other mainstream processes of OTC degradation. The O3/CaO2/HCO3- system may be considered as an efficient and economical approach for antibiotic destruction.

Muscle-secreted granulocyte colony-stimulating factor functions as metabolic niche factor ameliorating loss of muscle stem cells in aged mice.

The function and number of muscle stem cells (satellite cells, SCs) decline with muscle aging. Although SCs are heterogeneous and different subpopulations have been identified, it remains unknown whether a specific subpopulation of muscle SCs selectively decreases during aging. Here, we find that the number of SCs expressing high level of transcription factor Pax7 (Pax7Hi ) is dramatically reduced in aged mice. Myofiber-secreted granulocyte colony-stimulating factor (G-CSF) regulates age-dependent loss of Pax7Hi cells, as the Pax7Hi SCs are replenished by exercise-induced G-CSF in aged mice. Mechanistically, we show that transcription of G-CSF (Csf3) gene in myofibers is regulated by MyoD in a metabolism-dependent manner. Furthermore, myofiber-secreted G-CSF acts as a metabolic niche factor required for establishing and maintaining the Pax7Hi SC subpopulation in adult and physiological aged mice by promoting the asymmetric division of Pax7Hi and Pax7Mi SCs. Together, our findings uncover that muscles provide a metabolic niche regulating Pax7 SC heterogeneity in mice.

Reactive Nitrogen Species Generated by Gas-Liquid Dielectric Barrier Discharge for Efficient Degradation of Perfluorooctanoic Acid from Water.

Perfluorooctanoic acid (PFOA) poses a serious threat to the ecological environment and biological health because of its ubiquitous distribution, extreme persistence, and high toxicity. In this study, we designed a novel gas-liquid dielectric barrier discharge (GLDBD) reactor which could efficiently destruct PFOA. PFOA removal efficiencies can be obtained in various water matrices, which were higher than 98.0% within 50 min, with energy yields higher than 114.5 mg·kWh-1. It was confirmed that the reactive species including e-, ONOOH, •NO2, and hydroxyl radicals (•OH) were responsible for PFOA removal. Especially, this study first revealed the crucial role of reactive nitrogen species (RNS) for PFOA degradation in the plasma system. Due to the generation of a large amount of RNS, the designed GLDBD reactor proved to be less sensitive to various water matrices, which meant a broader promising practical application. Moreover, influential factors including high concentration of various ions and humic acid (HA), were investigated. The possible PFOA degradation pathways were proposed based on liquid chromatograph-mass spectrometer (LC-MS) results and density functional theory (DFT) calculation, which further confirmed the feasibility of PFOA removal with RNS. This research, therefore, provides an effective and versatile alternative for PFOA removal from various water matrices.

Linc-RAM is a metabolic regulator maintaining whole-body energy homeostasis in mice.

Long noncoding RNAs (lncRNAs) are known to have profound functions in regulating cell fate specification, cell differentiation, organogenesis, and disease, but their physiological roles in controlling cellular metabolism and whole-body metabolic homeostasis are less well understood. We previously identified a skeletal muscle-specific long intergenic noncoding RNA (linc-RNA) activator of myogenesis, Linc-RAM, which enhances muscle cell differentiation during development and regeneration. Here, we report that Linc-RAM exerts a physiological function in regulating skeletal muscle metabolism and the basal metabolic rate to maintain whole-body metabolic homeostasis. We first demonstrate that Linc-RAM is preferentially expressed in type-II enriched glycolytic myofibers, in which its level is more than 60-fold higher compared to that in differentiated myotubes. Consistently, genetic deletion of the Linc-RAM gene in mice increases the expression levels of genes encoding oxidative fiber versions of myosin heavy chains and decreases those of genes encoding rate-limiting enzymes for glycolytic metabolism. Physiologically, Linc-RAM-knockout mice exhibit a higher basal metabolic rate, elevated insulin sensitivity and reduced fat deposition compared to their wild-type littermates. Together, our findings indicate that Linc-RAM is a metabolic regulator of skeletal muscle metabolism and may represent a potential pharmaceutical target for preventing and/or treating metabolic diseases, including obesity.

Acetoacetate promotes muscle cell proliferation via the miR-133b/SRF axis through the Mek-Erk-MEF2 pathway.

Acetoacetate (AA) is an important ketone body that is used as an oxidative fuel to supply energy for the cellular activities of various tissues, including the brain and skeletal muscle. We recently revealed a new signaling role for AA by showing that it promotes muscle cell proliferation in vitro, enhances muscle regeneration in vivo, and ameliorates the dystrophic muscle phenotype of Mdx mice. In this study, we provide new molecular insight into this function of AA. We show that AA promotes C2C12 cell proliferation by transcriptionally upregulating the expression of muscle-specific miR-133b, which in turn stimulates muscle cell proliferation by targeting serum response factor. Furthermore, we show that the AA-induced upregulation of miR-133b is transcriptionally mediated by MEF2 via the Mek-Erk1/2 signaling pathway. Mechanistically, our findings provide further convincing evidence that AA acts as signaling metabolite to actively regulate various cellular activities in mammalian cells.

miR-378 and its host gene Ppargc1ß exhibit independent expression in mouse skeletal muscle.

MicroRNAs (miRNAs) are implicated in multiple biological processes in physiological and pathological settings. Nearly half of the known miRNAs are classified as 'intronic' miRNAs because they are embedded within the introns of protein-coding or noncoding genes. Such miRNAs were thought to be processed from primary host gene transcripts and share the promoter of their host. Recent analyses predicted that some intronic miRNAs might be transcribed and regulated as independent units, but there is little direct evidence for this in a specific biological context. Here, we focused on miR-378, which is located within the first intron of the peroxisome proliferator-activated receptor γ coactivator 1-beta (Ppargc1ß) gene and critically regulates skeletal muscle cell differentiation and muscle regeneration. We demonstrate that miR-378 and Ppargc1ß exhibit distinct expression patterns during skeletal muscle cell differentiation. In terminally differentiated adult skeletal muscle tissues of mice, miR-378 is predominantly expressed in glycolytic muscle, whereas Ppargc1ß is mainly expressed in oxidative soleus muscle. Mechanistically, miR-378, but not Ppargc1ß, is regulated by the transcription factor, MyoD, in muscle cells. Our findings identify a regulatory model of miR-378 expression, thereby helping us to understand its physiological function in skeletal muscle.

Myostatin promotes the epithelial-to-mesenchymal transition of the dermomyotome during somitogenesis.

BACKGROUND: Myostatin (MSTN), a member of the transforming growth factor-ß (TGF-ß) superfamily, has been implicated in the negative regulation of skeletal myogenesis. However, the molecular mechanism through which MSTN regulates early embryonic myogenesis is not well understood. RESULTS: We demonstrate that MSTN regulates early embryonic myogenesis by promoting the epithelial-to-mesenchymal transition (EMT) of the dermomyotome during somitogenesis in chicks. We show that the MSTN gene is first expressed at the center of the dermomyotome. As somitogenesis progresses, its expression extends dorsally and ventrally along the plane of the dermomyotome. By combining in situ hybridization and immunofluorescence assays, we demonstrate that the expression pattern of MSTN is spatiotemporally well correlated with EMT of the dermomyotome. Our gain- and loss-of-function experiments further reveal that MSTN can induce EMT of the chick dermomyotome. We also show that MSTN induces EMT of a nonsmall cell lung carcinoma cell line (A549) and Madin-Darby canine kidney cells in vitro. CONCLUSIONS: Our experimental data suggest that MSTN regulates myogenesis by promoting EMT during somitogenesis. These findings provide novel insights into the functions of MSTN during early embryonic myogenesis. Developmental Dynamics 247:1241-1252, 2018. © 2018 Wiley Periodicals, Inc.

A novel brown adipocyte-enriched long non-coding RNA that is required for brown adipocyte differentiation and sufficient to drive thermogenic gene program in white adipocytes.

The thermogenic activities of brown and beige adipocytes can be exploited to reduce energy surplus and counteract obesity. Recent RNA sequencing studies have uncovered a number of long noncoding RNAs (lncRNAs) uniquely expressed in white and brown adipose tissues (WAT and BAT), but whether and how these lncRNAs function in adipogenesis remain largely unknown. Here, we report the identification of a novel brown adipocyte-enriched LncRNA (AK079912), and its nuclear localization, function and regulation. The expression of AK079912 increases during brown preadipocyte differentiation and in response to cold-stimulated browning of white adipocytes. Knockdown of AK079912 inhibits brown preadipocyte differentiation, manifested by reductions in lipid accumulation and down-regulation of adipogenic and BAT-specific genes. Conversely, ectopic expression of AK079912 in white preadipocytes up-regulates the expression of genes involved in thermogenesis. Mechanistically, inhibition of AK079912 reduces mitochondrial copy number and protein levels of mitochondria electron transport chain (ETC) complexes, whereas AK079912 overexpression increases the levels of ETC proteins. Lastly, reporter and pharmacological assays identify Pparγ as an upstream regulator of AK079912. These results provide new insights into the function of non-coding RNAs in brown adipogenesis and regulating browning of white adipocytes.

Linc-RAM is required for FGF2 function in regulating myogenic cell differentiation.

Myogenic differentiation of skeletal muscle stem cells, also known satellite cells, is tightly orchestrated by extrinsic and intrinsic regulators. Basic fibroblast growth factor (FGF2) is well documented to be implicated in satellite cell self-renewal and differentiation by repressing MyoD. We recently identified a MyoD-regulated and skeletal muscle-specifically expressed long non-coding RNA Linc-RAM which enhances myogenic differentiation by facilitating MyoD/Baf60c/Brg1 complex assembly. Herein, we investigated the transcriptional regulation and intracellular signaling pathway in mediating Linc-RAM gene expression during muscle cell differentiation. Firstly, we demonstrate Linc-RAM is negatively regulated by FGF2 via Ras/Raf/Mek/Erk signaling pathway in muscle cells. Overexpression of MyoD significantly attenuates repression of Linc-RAM promoter activities in C2C12 cells treated with FGF2. Knockout of MyoD abolishes FGF2-mediated repression of Linc-RAM gene transcription in satellite cells sorted from skeletal muscle of MyoD-/-;Pax7-nGFP mice, suggesting inhibition of MyoD is required for FGF2-mediated expression of Linc-RAM. For the functional significance, we show that overexpression of Linc-RAM rescues FGF2-induced inhibition of C2C12 cell differentiation, indicating inhibition of Linc-RAM is required for FGF2-mediated suppression of myogenic differentiation. Consistently, we are able to further corroborate the requirement of Linc-RAM inhibition for FGF2-modulated repression of myogenic differentiation by using an ex vivo cultured single fiber system and satellite cells sorted from Linc-RAM-/-;Pax7-nGFP knockout mice. Collectively, the present study not only reveals the intracellular signaling in FGF2-mediated Linc-RAM gene expression but also demonstrate the functional significance of Linc-RAM in FGF2-mediated muscle cell differentiation.

Acetoacetate Accelerates Muscle Regeneration and Ameliorates Muscular Dystrophy in Mice.

Acetoacetate (AA) is a ketone body and acts as a fuel to supply energy for cellular activity of various tissues. Here, we uncovered a novel function of AA in promoting muscle cell proliferation. Notably, the functional role of AA in regulating muscle cell function is further evidenced by its capability to accelerate muscle regeneration in normal mice, and it ameliorates muscular dystrophy in mdx mice. Mechanistically, our data from multiparameter analyses consistently support the notion that AA plays a non-metabolic role in regulating muscle cell function. Finally, we show that AA exerts its function through activation of the MEK1-ERK1/2-cyclin D1 pathway, revealing a novel mechanism in which AA serves as a signaling metabolite in mediating muscle cell function. Our findings highlight the profound functions of a small metabolite as signaling molecule in mammalian cells.

miR-431 is involved in regulating cochlear function by targeting Eya4.

To understand the relationship between microRNAs and hearing loss and help clarify the causes of hereditary deafness, we studied the functions of miR-431 in cochleae. We first investigated the spatial-temporal expression profiles of miR-431 in spiral ganglion neurons (SGNs) in cochleae using real-time PCR and miRNA in situ hybridization. These studies showed that expression of miR-431 was high in SGNs in the cochleae of newborn mice, and decreased as development progressed. To test the functional effects of miR-431, we established miR-431 overexpressing transgenic (Tg) mice. Surface preparations of the cochlear basilar membrane and cochlear sections revealed no major structural differences between Tg and wild-type (Wt) mice. However, a comparison of auditory brain stem responses (ABRs) in Tg and Wt mice showed that ABR thresholds were significantly higher in Tg mice than in Wt mice. Notably, the density of SGNs was significantly lower in Tg mice than in Wt mice. We also found that the proportion of mature SGNs in cultures of primary SGNs from Tg cochleae was lower and their axons were shorter. A bioinformatics analysis predicted that the mRNA target of miR-431 was Eya4, a finding confirmed by luciferase reporter assays and western blotting. Importantly, overexpression of miR-431 in cochleae of Tg mice inhibited the translation of Eya4 mRNA, leading to a deficiency of EYA4. Thus, excessive amounts of miR-431 in cochleae of Tg mice may be the cause of sparse SGNs, which in turn could be responsible for hearing loss.

miR-30e is negatively regulated by myostatin in skeletal muscle and is functionally related to fiber-type composition.

Myostatin (MSTN) negatively regulates skeletal myogenesis in which microRNAs (miRNAs) also play critical roles. Using miRNA microarrays of skeletal muscle from MSTN-knockout (MSTN-/-) mice, we recently showed that miR-431 is regulated by MSTN signaling. To identify additional miRNAs regulated by MSTN, we re-analyzed these miRNA arrays and validated their expression by quantitative RT-PCR. Herein, we demonstrated that miR-30e was significantly upregulated in skeletal muscle of MSTN-/- mice compared with that of the wild-type littermates. Importantly, the predicted targets of miR-30e are functionally involved in myocyte differentiation and fiber-type formation. Using luciferase reporter gene assays, we further showed that peroxisome proliferator-activated receptor gamma, coactivator 1 alpha (Pgc1α), is a direct target of miR-30e. Overexpression of miR-30e in C2C12 cells significantly decreased Pgc1α and increased type II form of myosin heavy chain gene expression, suggesting that miR-30e functionally associates with glycolytic myofiber formation. Thus, our data indicate that the altered fiber-type composition in MSTN-/- mice are attributable in part to deregulated expression of miR-30e.

miR-378 attenuates muscle regeneration by delaying satellite cell activation and differentiation in mice.

Skeletal muscle mass and homeostasis during postnatal muscle development and regeneration largely depend on adult muscle stem cells (satellite cells). We recently showed that global overexpression of miR-378 significantly reduced skeletal muscle mass in mice. In the current study, we used miR-378 transgenic (Tg) mice to assess the in vivo functional effects of miR-378 on skeletal muscle growth and regeneration. Cross-sectional analysis of skeletal muscle tissues showed that the number and size of myofibers were significantly lower in miR-378 Tg mice than in wild-type mice. Attenuated cardiotoxin-induced muscle regeneration in miR-378 Tg mice was found to be associated with delayed satellite cell activation and differentiation. Mechanistically, miR-378 was found to directly target Igf1r in muscle cells both in vitro and in vivo These miR-378 Tg mice may provide a model for investigating the physiological and pathological roles of skeletal muscle in muscle-associated diseases in humans, particularly in sarcopenia.

Myostatin regulates miR-431 expression via the Ras-Mek-Erk signaling pathway.

MicroRNAs (miRNAs) play critical regulatory roles in controlling myogenic development both in vitro and in vivo; however, the molecular mechanisms underlying transcriptional regulation of miRNA genes in skeletal muscle cells are largely unknown. Here, using a microarray hybridization approach, we identified myostatin-regulated miRNA genes in skeletal muscle tissues by systematically searching miRNAs that are differentially expressed between wild-type and myostatin-null mice during development. We found that 116 miRNA genes were differentially expressed in muscles between these mice across different developmental stages. We further characterized myostatin-regulated miR-431 was upregulated in skeletal muscle tissues of myostatin-null mice. In functional studies, we found that overexpression of miR-431 in C2C12 myoblast cells attenuated myostatin-induced suppression of myogenic differentiation. Mechanistic studies further demonstrated that myostatin acted through the Ras-Mek-Erk signaling pathway to transcriptionally regulate miR-431 expression C2C12 cells. Our findings provide new insight into the mechanisms underlying transcriptional regulation of miRNA genes by myostatin during skeletal muscle development.

E3 ubiquitin ligase RNF13 involves spatial learning and assembly of the SNARE complex.

Changes in the structure and number of synapses modulate learning, memory and cognitive disorders. Ubiquitin-mediated protein modification is a key mechanism for regulating synaptic activity, though the precise control of this process remains poorly understood. RING finger protein 13 (RNF13) is a recently identified E3 ubiquitin ligase, and its in vivo function remains completely unknown. We show here that genetic deletion of RNF13 in mice leads to a significant deficit in spatial learning as determined by the Morris water maze test and Y-maze learning test. At the ultrastructral level, the synaptic vesicle density was decreased and the area of the active zone was increased at hippocampal synapses of RNF13-null mice compared with those of wild-type littermates. We found no change in the levels of SNARE (soluble N-ethylmaleimide-sensitive factor-attachment protein receptor) complex proteins in the hippocampus of RNF13-null mice, but impaired SNARE complex assembly. RNF13 directly interacted with snapin, a SNAP-25-interacting protein. Interestingly, snapin was ubiquitinated by RNF13 via the lysine-29 conjugated polyubiquitin chain, which in turn promoted the association of snapin with SNAP-25. Consistently, we found an attenuated interaction between snapin and SNAP-25 in the RNF13-null mice. Therefore, these results suggest that RNF13 is involved in the regulation of the SNARE complex, which thereby controls synaptic function.

SEPDB: a database of secreted proteins.

Detecting changes in the dynamics of secreted proteins in serum has been a challenge for proteomics. Enter secreted protein database (SEPDB), an integrated secretory proteomics database offering human, mouse and rat secretory proteomics datasets collected from serum, exosomes and cell culture media. SEPDB compiles secreted protein information from secreted protein database, UniProt and Human Protein Atlas databases to annotate secreted proteomics data based on protein subcellular localization and disease markers. SEPDB integrates the latest predictive modeling techniques to measure deviations in the distribution of signal peptide structures of secreted proteins, extends signal peptide sequence prediction by excluding transmembrane structural domain proteins and updates the validation analysis pipeline for secreted proteins. To establish tissue-specific profiles, we have also created secreted proteomics datasets associated with different human tissues. In addition, we provide information on heterogeneous receptor network organizational relationships, reflective of the complex functional information inherent in the molecular structures of secreted proteins that serve as ligands. Users can take advantage of the Refreshed Search, Analyze, Browse and Download functions of SEPDB, which is available online at https://sysomics.com/SEPDB/. Database URL:  https://sysomics.com/SEPDB/.

Computational prediction of associations between long non-coding RNAs and proteins.

BACKGROUND: Though most of the transcripts are long non-coding RNAs (lncRNAs), little is known about their functions. lncRNAs usually function through interactions with proteins, which implies the importance of identifying the binding proteins of lncRNAs in understanding the molecular mechanisms underlying the functions of lncRNAs. Only a few approaches are available for predicting interactions between lncRNAs and proteins. In this study, we introduce a new method lncPro. RESULTS: By encoding RNA and protein sequences into numeric vectors, we used matrix multiplication to score each RNA-protein pair. This score can be used to measure the interactions between an RNA-protein pair. This method effectively discriminates interacting and non-interacting RNA-protein pairs and predicts RNA-protein interactions within a given complex. Applying this method on all human proteins, we found that the long non-coding RNAs we collected tend to interact with nuclear proteins and RNA-binding proteins. CONCLUSIONS: Compared with the existing approaches, our method shortens the time for training matrix and obtains optimal results based on the model being used. The ability of predicting the associations between lncRNAs and proteins has also been enhanced. Our method provides an idea on how to integrate different information into the prediction process.

Identification of long non-protein coding RNAs in chicken skeletal muscle using next generation sequencing.

Vertebrate genomes encode thousands of non-coding RNAs including short non-coding RNAs (such as microRNAs) and long non-coding RNAs (lncRNAs). Chicken (Gallus gallus) is an important model organism for developmental biology, and the recently assembled genome sequences for chicken will facilitate the understanding of the functional roles of non-coding RNA genes during development. The present study concerns the first systematic identification of lncRNAs using RNA-Seq to sample the transcriptome during chicken muscle development. A computational approach was used to identify 281 new intergenic lncRNAs in the chicken genome. Novel lncRNAs in general are less conserved than protein-coding genes and slightly more conserved than random non-coding sequences. The present study has provided an initial chicken lncRNA catalog and greatly increased the number of chicken ncRNAs in the non-protein coding RNA database. Furthermore, the computational pipeline presented in the current work will be useful for characterizing lncRNAs obtained from deep sequencing data.

Polyurethane Foam Skeleton-Based Phase Change Hydrogel for Efficient Battery Thermal Management with Favorable Antivibration Performance.

Efficient thermal management is critical to ensure the safe and reliable operation of lithium-ion batteries (LIBs) as they are highly sensitive to temperature changes. Meanwhile, LIBs are exposed to various external forces during operation, such as vibration, shock, and oscillation, which may disrupt the physical and chemical processes inside the battery and lead to a decreased performance and shortened life. Here, we designed a phase change hydrogel (PCH) pad based on the polyurethane (PU) foam skeleton and demonstrated its effectiveness in efficient thermal management and improving antivibration performance. The thermal conductivity of the prepared composite is 0.65 W/(m·K), while the thermal contact resistance could decrease to ∼20 K·cm2/W under 60 °C. It exhibits a flexible contact transformation during the phase transition, resulting in enhanced interfacial heat transfer and storage rate, as well as improved resistance against external impacts. The temperature of the battery module wrapped with a composite plate decreases by 11.4 °C during the 6C discharge. Moreover, the additional heat generated by external vibration is only half that of the bare battery, and the temperature difference could reach 5.2 °C, demonstrating the effective buffering effect of PCH@PU in mitigating long-term discharge-induced increases in internal resistance. The developed PCH@PU, known for its exceptional thermal management and favorable antivibration performance, holds promising potential for widespread utilization in the field of power battery heat dissipation.

Resolving a nearly 90-year-old enigma: The rare Fagus chienii is conspecific with F. hayatae based on molecular and morphological evidence.

Taxonomic uncertainties of rare species often hinder effective prioritization for conservation. One such taxonomic uncertainty is the 90-year-old enigma of Fagus chienii. F. chienii was previously only known from the type specimens collected in 1935 in Pingwu County of Sichuan Province, China, and has long been thought to be on the verge of extinction. However, morphological similarities to closely related Fagus species have led many to question the taxonomic status of F. chienii. To clarify this taxonomic uncertainty, we used the newly collected samples to reconstruct a molecular phylogeny of Chinese Fagus species against the phylogenetic backbone of the whole genus using seven nuclear genes. In addition, we examined nine morphological characters to determine whether F. chienii is morphologically distinct from its putatively closest relatives (F. hayatae, F.longipetiolata, and F.lucida). Both morphological and phylogenetic analyses indicated that F. chienii is conspecific with F. hayatae. We recommended that F. chienii should not be treated as a separate species in conservation management. However, conservation strategies such as in situ protection and ex situ germplasm preservation should be adopted to prevent the peculiar "F. chienii" population from extinction.