Background
Skeletal muscle atrophy induced by either aging (sarcopenia) or mechanical unloading is associated with serious health consequences. Long non‐coding RNAs (lncRNAs) are implicated as ...important regulators in numerous physiological and pathological processes.
Methods
Microarray analysis was performed to identify the differentially expressed lncRNAs in skeletal muscle between adult and aged mice. The most decreased lncRNA in aged skeletal muscle was identified. The C2C12 mouse myoblast cells were used to assess the biological function of the lncRNA in vitro. The target microRNA of lncRNA and the target protein of microRNA were predicted by bioinformatics analysis and validated in vitro. Furthermore, the biology function of the lncRNA in vivo was investigated by local overexpression or knockdown the lncRNA in skeletal muscle. The therapeutic effect of the lncRNA overexpression in age‐related or mechanical unloading‐induced muscle atrophy was also evaluated.
Results
We identified a novel lncRNA (muscle anabolic regulator 1, MAR1) which was highly expressed in mice skeletal muscle and positively correlated with muscle differentiation and growth in vitro and in vivo. We predicted and validated that microRNA‐487b (miR‐487b) was a direct target of MAR1. We also predicted and validated that Wnt5a, an important regulator during myogenesis, was a target of miR‐487b in C2C12 cells. Our findings further demonstrated that enforced MAR1 expression in myoblasts led to derepression of Wnt5a. Moreover, MAR1 promoted skeletal muscle mass/strength and Wnt5a protein level in mice. Enforced MAR1 expression in mice attenuated muscle atrophy induced by either aging or unloading.
Conclusions
The newly identified lncRNA MAR1 acts as a miR‐487b sponge to regulate Wnt5a protein, resulting in promoting muscle differentiation and regeneration. MAR1 could be a novel therapeutic target for treating muscle atrophy induced by either aging or mechanical unloading.
The development of artificial intelligence (AI)-based technologies in medicine is advancing rapidly, but real-world clinical implementation has not yet become a reality. Here we review some of the ...key practical issues surrounding the implementation of AI into existing clinical workflows, including data sharing and privacy, transparency of algorithms, data standardization, and interoperability across multiple platforms, and concern for patient safety. We summarize the current regulatory environment in the United States and highlight comparisons with other regions in the world, notably Europe and China.
We report epidemiological and clinical investigations on ten pediatric SARS-CoV-2 infection cases confirmed by real-time reverse transcription PCR assay of SARS-CoV-2 RNA. Symptoms in these cases ...were nonspecific and no children required respiratory support or intensive care. Chest X-rays lacked definite signs of pneumonia, a defining feature of the infection in adult cases. Notably, eight children persistently tested positive on rectal swabs even after nasopharyngeal testing was negative, raising the possibility of fecal-oral transmission.
Lactate is a prominent energy substrate for oxidative tumor cells. Interfering with the lactate‐fueled respiration of oxidative tumor cells would be a promising therapeutic strategy for cancer ...treatment. In this study, α‐cyano‐4‐hydroxycinnamate (CHC) is incorporated into a porous Zr (IV)‐based porphyrinic metal‐organic framework (PZM) nanoparticle, to reduce the lactate uptake by inhibiting the expression of lactate‐proton symporter, monocarboxylate transporter 1 (MCT1) in tumor cells, thus transform lactate‐fueled aerobic respiration to anaerobic glycolysis. The alteration in energy supply can also decrease the oxygen consumption in tumor cells, which would facilitate the photodynamic therapy (PDT) in cancer treatment. Moreover, hyaluronic acid (HA) is coated on the surface of PZM nanoparticles for CD44‐targeting and hyaluronidase‐induced intracellular drug releasing. Both in vitro and in vivo studies confirmed good biocompatibility and enhanced PDT efficacy of the HA‐coated PZM nanoparticles (CHC‐PZM@HA) in tumor cells. The CHC‐PZM@HA platform will provide a new perspective in cancer therapy.
Enhanced photodynamic therapy (PDT) by inhibiting lactate uptake. Hyaluronic acid modified porphyrinic metal‐organic framework nanoparticles delivered MCT1 inhibitor into cancer cells. With the releasing of loaded drugs by enzymatic degradation, the aerobic respiration of lactate is disturbed and intratumoral oxygen pressure is upregulated. The nanocarrier system significant enhances the anticancer effect of PDT.
The ability to identify a specific cancer using minimally invasive biopsy holds great promise for improving the diagnosis, treatment selection, and prediction of prognosis in cancer. Using ...whole-genome methylation data from The Cancer Genome Atlas (TCGA) and machine learning methods, we evaluated the utility of DNA methylation for differentiating tumor tissue and normal tissue for four common cancers (breast, colon, liver, and lung). We identified cancer markers in a training cohort of 1,619 tumor samples and 173 matched adjacent normal tissue samples. We replicated our findings in a separate TCGA cohort of 791 tumor samples and 93 matched adjacent normal tissue samples, as well as an independent Chinese cohort of 394 tumor samples and 324 matched adjacent normal tissue samples. The DNA methylation analysis could predict cancer versus normal tissue with more than 95% accuracy in these three cohorts, demonstrating accuracy comparable to typical diagnostic methods. This analysis also correctly identified 29 of 30 colorectal cancer metastases to the liver and 32 of 34 colorectal cancer metastases to the lung. We also found that methylation patterns can predict prognosis and survival. We correlated differential methylation of CpG sites predictive of cancer with expression of associated genes known to be important in cancer biology, showing decreased expression with increased methylation, as expected. We verified gene expression profiles in a mouse model of hepatocellular carcinoma. Taken together, these findings demonstrate the utility of methylation biomarkers for the molecular characterization of cancer, with implications for diagnosis and prognosis.
Inhibition of glutamine metabolism in tumor cells can cause metabolic compensation‐mediated glycolysis enhancement and PD‐L1 upregulation‐induced immune evasion, significantly limiting the ...therapeutic efficacy of glutamine inhibitors. Here, inspired by the specific binding of receptor and ligand, a PD‐L1‐targeting metabolism and immune regulator (PMIR) are constructed by decorating the glutaminase inhibitor (BPTES)‐loading zeolitic imidazolate framework (ZIF) with PD‐L1‐targeting peptides for regulating the metabolism within the tumor microenvironment (TME) to improve immunotherapy. At tumor sites, PMIR inhibits glutamine metabolism of tumor cells for elevating glutamine levels within the TME to improve the function of immune cells. Ingeniously, the accompanying PD‐L1 upregulation on tumor cells causes self‐amplifying accumulation of PMIR through PD‐L1 targeting, while also blocking PD‐L1, which has the effects of converting enemies into friends. Meanwhile, PMIR exactly offsets the compensatory glycolysis, while disrupting the redox homeostasis in tumor cells via the cooperation of components of the ZIF and BPTES. These together cause immunogenic cell death of tumor cells and relieve PD‐L1‐mediated immune evasion, further reshaping the immunosuppressive TME and evoking robust immune responses to effectively suppress bilateral tumor progression and metastasis. This work proposes a rational strategy to surmount the obstacles in glutamine inhibition for boosting existing clinical treatments.
A PD‐L1‐targeting metabolism and immune regulator (PMIR) is constructed for metabolic reprogramming. PMIR inhibits glutamine metabolism of tumor cells, while solves compensatory glycolysis and utilizes upregulated PD‐L1 for self‐amplifying accumulation. Cooperating with the immunogenic cell death through the disruption of the redox homeostasis, PMIR can evoke robust immune responses to suppress bilateral tumor progression and metastasis.
By integrating the characteristics of each therapy modality and material chemistry, a multitherapy modality is put forward: tumor starvation triggered synergism with sensitized chemotherapy. ...Following starvation‐induced amplification of pathological abnormalities in tumors, chemotherapy is arranged to be locally activated and accurately reinforced to perfect multitherapy synergism from spatial and temporal perspectives. To this end, glucose oxidase (GOD) and a hypoxic prodrug of tirapazamine (TPZ) are loaded in acidity‐decomposable calcium carbonate (CaCO3) nanoparticles concurrently tethered by hyaluronic acid. This hybrid nanotherapeutic shows a strong tendency to accumulate in tumors postinjection due to the cooperation between passive and active targeting mechanisms. The GOD‐driven oxidation reaction deprives tumors of glucose for starvation therapy and concomitantly induces tumorous abnormality amplifications including elevated acidity and exacerbated hypoxia. Programmatically, the acidity amplification causes CaCO3 decomposition, offering not only spatial control over the liberation of embedded TPZ just within tumors but also the temporal control over timely chemotherapy initiation to match the occurrence of hypoxia amplification and thus benefiting perfect synergism between starvation therapy and chemotherapy.
This study reports a multitherapy modality of tumor starvation triggered synergism with sensitized chemotherapy. Tumor starvation confers not only spatial control over the chemotherapeutic exposure just to tumors but also the temporal control over timely chemotherapy initiation to match the occurrence of hypoxia amplification needed for chemotherapy reinforcement, thus benefiting perfect synergism between starvation therapy and chemotherapy.
Adjacent CpG sites in mammalian genomes can be co-methylated owing to the processivity of methyltransferases or demethylases, yet discordant methylation patterns have also been observed, which are ...related to stochastic or uncoordinated molecular processes. We focused on a systematic search and investigation of regions in the full human genome that show highly coordinated methylation. We defined 147,888 blocks of tightly coupled CpG sites, called methylation haplotype blocks, after analysis of 61 whole-genome bisulfite sequencing data sets and validation with 101 reduced-representation bisulfite sequencing data sets and 637 methylation array data sets. Using a metric called methylation haplotype load, we performed tissue-specific methylation analysis at the block level. Subsets of informative blocks were further identified for deconvolution of heterogeneous samples. Finally, using methylation haplotypes we demonstrated quantitative estimation of tumor load and tissue-of-origin mapping in the circulating cell-free DNA of 59 patients with lung or colorectal cancer.
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