Exploration of identifying individual tumor tissue based on probabilistic model.

Variations in the tumor genome can result in allelic changes compared to the reference profile of its homogenous body source on genetic markers. This brings a challenge to source identification of tumor samples, such as clinically collected pathological paraffin-embedded tissue and sections. In this study, a probabilistic model was developed for calculating likelihood ratio (LR) to tackle this issue, which utilizes short tandem repeat (STR) genotyping data. The core of the model is to consider tumor tissue as a mixture of normal and tumor cells and introduce the incidence of STR variants (φ) and the percentage of normal cells (Mxn) as a priori parameters when performing calculations. The relationship between LR values and φ or Mxn was also investigated. Analysis of tumor samples and reference blood samples from 17 colorectal cancer patients showed that all samples had Log 10(LR) values greater than 1014. In the non-contributor test, 99.9% of the quartiles had Log 10(LR) values less than 0. When the defense's hypothesis took into account the possibility that the tumor samples came from the patient's relatives, LR greater than 0 was still obtained. Furthermore, this study revealed that LR values increased with decreasing φ and increasing Mxn. Finally, LR interval value was provided for each tumor sample by considering the confidence interval of Mxn. The probabilistic model proposed in this paper could deal with the possibility of tumor allele variability and offers an evaluation of the strength of evidence for determining tumor origin in clinical practice and forensic identification.

An innovative label-free electrochemical aptamer sensor: utilizing Ti3C2Tx/MoS2/Au NPs for accurate interleukin-6 detection.

In the medical field, changes in interleukin-6 (IL-6) concentration serve as essential biomarkers for monitoring and diagnosing various conditions, including acute inflammatory responses such as those seen in trauma and burns, and chronic illnesses like cancer. This paper detailed a label-free electrochemical aptamer sensor designed for IL-6 quantification. A composite material consisting of Ti3C2Tx and MoS2 was successfully synthesized to fabricate this sensor. The synergistic effect of MoS2's catalytic action on hydrogen peroxide (H2O2), used as a signalling marker, when combined with the exceptional conductivity and large specific surface area of Ti3C2Tx, not only enables an increased loading of MoS2 but also significantly boosts the electrochemical response. The in situ-reduced Au NPs provided stable immobilization sites for DNA aptamers (DNAapt) and facilitated electron transfer, ensuring accurate IL-6 recognition. Under optimal conditions, the aptamer sensor exhibited a wide linear range (5 pg/mL to 100 ng/mL) and a low limit of detection (LOD) of 2.9 pg/mL. Its sensing performance in human serum samples highlights its potential as a promising clinical analysis tool.

A Self-Amplifying ROS-Responsive Nanoplatform for Simultaneous Cuproptosis and Cancer Immunotherapy.

Cuproptosis is an emerging cell death pathway that depends on the intracellular Cu ions. Elesclomol (ES) as an efficient Cu ionophore can specifically transport Cu into mitochondria and trigger cuproptosis. However, ES can be rapidly removed and metabolized during intravenous administration, leading to a short half-life and limited tumor accumulation, which hampers its clinical application. Here, the study develops a reactive oxygen species (ROS)-responsive polymer (PCP) based on cinnamaldehyde (CA) and polyethylene glycol (PEG) to encapsulate ES-Cu compound (EC), forming ECPCP. ECPCP significantly prolongs the systemic circulation of EC and enhances its tumor accumulation. After cellular internalization, the PCP coating stimulatingly dissociates exposing to the high-level ROS, and releases ES and Cu, thereby triggering cell death via cuproptosis. Meanwhile, Cu2+-stimulated Fenton-like reaction together with CA-stimulated ROS production simultaneously breaks the redox homeostasis, which compensates for the insufficient oxidative stress treated with ES alone, in turn inducing immunogenic cell death of tumor cells, achieving simultaneous cuproptosis and immunotherapy. Furthermore, the excessive ROS accelerates the stimuli-dissociation of ECPCP, forming a positive feedback therapy loop against tumor self-alleviation. Therefore, ECPCP as a nanoplatform for cuproptosis and immunotherapy improves the dual antitumor mechanism of ES and provides a potential optimization for ES clinical application.

The Function, Underlying Mechanism and Clinical Potential of Exosomes in Colorectal Cancer.

Colorectal cancer (CRC) is a lethal malignancy worldwide. Exosomes are extracellular vesicles derived from the endosomal pathway of nearly all cells and can be found in body fluids. They can be considered an intercellular system in the human body that can mediate near- and long-distance intercellular communication due to their features and functions. Investigations have revealed that exosomes are participated in different processes, physiologically and pathologically, especially in cancer. However, the clinical value of exosomes and their mechanisms of action in CRC are unclear and have not been systematically assessed. The purpose of this review is to discuss how exosomes play a role in the occurrence and development of CRC, with a particular focus on the functions and underlying mechanisms of tumor-derived exosomes as well as non-tumor-derived exosomes. We also describe the evidence that exosomes can be used as diagnostic and prognostic markers for CRC. In addition, the possibilities of exosomes in CRC clinical transformation are also discussed.

A novel nomogram for predicting the prolonged length of stay in post-anesthesia care unit after elective operation.

BACKGROUND: Prolonged length of stay in post-anesthesia care unit (PLOS in PACU) is a combination of risk factors and complications that can compromise quality of care and operating room efficiency. Our study aimed to develop a nomogram to predict PLOS in PACU of patients undergoing elective surgery. METHODS: Data from 24017 patients were collected. Least absolute shrinkage and selection operator (LASSO) was used to screen variables. A logistic regression model was built on variables determined by a combined method of forward selection and backward elimination. Nomogram was designed with the model. The nomogram performance was evaluated with the area under the receiver operating characteristic curve (AUC) for discrimination, calibration plot for consistency between predictions and actuality, and decision curve analysis (DCA) for clinical application value. RESULTS: A nomogram was established based on the selected ten variables, including age, BMI < 21 kg/m2, American society of Anesthesiologists Physical Status (ASA), surgery type, chill, delirium, pain, naloxone, operation duration and blood transfusion. The C-index value was 0.773 [95% confidence interval (CI) = 0.765 - 0.781] in the development set and 0.757 (95% CI = 0.744-0.770) in the validation set. The AUC was > 0.75 for the prediction of PLOS in PACU. The calibration curves revealed high consistencies between the predicted and actual probability. The DCA showed that if the threshold probability is over 10% , using the models to predict PLOS in PACU and implement intervention adds more benefit. CONCLUSIONS: This study presented a nomogram to facilitate individualized prediction of PLOS in PACU for patients undergoing elective surgery.

Nano Self-Assemblies of Caffeic Acid-Fibronectin Mimic a Peptide Conjugate for the Treatment of Corneal Epithelial Injury.

Rapid corneal re-epithelialization is important for corneal wound healing. Corneal epithelial cell motility and oxidative stress are important targets for therapeutic intervention. In this study, we covalently conjugated the antioxidant caffeic acid (CA) with a bioactive peptide sequence (PHSRN) to generate a CA-PHSRN amphiphile, which was formulated into nanoparticular eye drops with an average size of 43.21 ± 16 nm. CA-PHSRN caused minimal cytotoxicity against human corneal epithelial cells (HCECs) and RAW264.7 cells, exhibited an excellent free radical scavenging ability, and remarkably attenuated reactive oxygen species (ROS) levels in H2O2-stimulated HCECs. The antioxidant and anti-inflammatory activities of CA-PHSRN were assessed in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. The results show that CA-PHSRN treatment effectively prevented LPS-induced DNA damage and significantly reduced the levels of LPS-induced pro-inflammatory cytochemokines (i.e., iNOS, NO, TNF-α, IL-6, and COX-2) in a dose-dependent manner. Moreover, using a rabbit corneal epithelial ex vivo migration assay, we demonstrated that the proposed CA-PHSRN accelerated corneal epithelial cell migration and exhibited high ocular tolerance and ocular bioavailability after topical instillation. Taken together, the proposed CA-PHSRN nanoparticular eye drops are a promising therapeutic formulation for the treatment of corneal epithelial injury.

Attenuated Salmonella-delivered PD-1 siRNA enhances the antitumor effects of EZH2 inhibitors in colorectal cancer.

Immunotherapy has made significant progress in the treatment of malignant tumors. However, strategies to combine immunotherapy with anticancer drugs have attracted great attention due to the low response rate and unique toxicity profile of immunotherapies and the subsequent development of acquired resistance in some initial responders. EZH2, a histone methyl transferase subunit of a Polycomb repressor complex,is highly expressed in a variety of tumors, and targeting EZH2 has become a new strategy for tumor therapy and drug combination. Here，we studied the effect of EZH2 inhibitors on colorectal cancer cells and their combination with immunotherapy. Our results demonstrated that EZH2 inhibitors can not only significantly inhibit the survival of colorectal cancer (CRC) cells and induce apoptosis, effectively inhibit cell invasion and migration, but also cause an increase in the expression of PD-L1 receptors on the cell surface. To determine the effect of EZH2 in combination with immunotherapy, we combine EZH2 inhibitors with PD-1 siRNA delivered by attenuated Salmonella. The vivo experiments have shown that the combination of EZH2 inhibitors and Salmonella-delivered PD-1 siRNA can further inhibit the development of CRC, trigger effective anti-tumor immunity, and improve therapeutic efficacy. Its underlying mechanisms mainly involve synergistic immunomodulation and apoptosis. This study suggests an emerging strategy based on a combination of EZH2 inhibitor and immunotherapy based on PD-1 inhibition.

To Investigate the Occurrence and Development of Colorectal Cancer Based on the PI3K/AKT/mTOR Signaling Pathway.

Colorectal cancer (CRC) is the most common malignancy of the gastrointestinal, however, the underlying mechanisms of CRC remain largely unknown. New evidence suggests that the PI3K/AKT/mTOR pathway is closely related to CRC. PI3K/AKT/mTOR is a classical signaling pathway that is involved in a variety of biological processes, such as regulating cellular metabolism, autophagy, cell cycle progression, cell proliferation, apoptosis, and metastasis. Therefore, it plays a crucial role in the occurrence and development of CRC. In this review, we focus on the role of the PI3K/AKT/mTOR pathway in CRC, and its application of to the treatment of CRC. We review the importance of the PI3K/AKT/mTOR signaling pathway in tumorigenesis, proliferation and progression, and pre-clinical and clinical experience with several PI3K/AKT/mTOR pathway inhibitors in CRC.

Highly stable fibronectin-mimetic-peptide-based supramolecular hydrogel to accelerate corneal wound healing.

Without timely treatment, poor wound healing in corneal injuries can seriously impair vision and lead to blindness. Thus, it is vital to develop a therapeutic strategy to accelerate corneal re-epithelialization. The conjugation of self-assembled motifs with a fibronectin-mimetic peptide sequence (PHSRN) drastically improves the chemical stability of PHSRN against protease hydrolysis and minimally affects its biological activity to promote the migration of corneal epithelial cells. The optimized Nap-FFPHSRN self-assembled into bioactive supramolecular hydrogels increases cell motility by remolding F-actin and boosts the tight junction of the corneal epithelium by increasing the expression of zonula occludens-1 (ZO-1). An in vivo experiment showed that a Nap-FFPHSRN hydrogel provided extended precorneal retention with good ocular tolerance after topical instillation. An animal model of corneal scrape showed that a single daily dose of Nap-FFPHSRN hydrogel had a superior therapeutic effect in facilitating corneal re-epithelialization with complete morphological and architectural recovery. With a rational approach to mimic bioactive proteins, this study presents a new strategy to demonstrate the potential of peptide-based supramolecular hydrogels for use in clinical treatment of corneal injury. STATEMENT OF SIGNIFICANCE: Here we systematically investigate the self-assembly behavior and chemical stability of designed peptide amphiphiles (Nap-FPHRSN, Nap-FFPHSRN and Nap-FFFPHSRN). The introduction of self-assembled motifs (Nap-F, Nap-FF and Nap-FFF) drastically enhances the chemical stability of fibronectin-mimetic peptide (PHSRN). Moreover, topical instillation of Nap-FFPHSRN hydrogel once daily, exhibits a better in vivo effect than PHSRN and the same in vivo effect as fibronectin, both of which are instilled three times daily, for promoting full morphological and architectural recovery after corneal re-epithelialization. As a rational design of conjugating bioactive peptides with self-assembled motifs to mimic bioactive proteins, this work may lead to a new approach that improves the in vivo therapeutic effect for treating corneal injury in clinic settings.

Hsa_Circ_0000826 inhibits the proliferation of colorectal cancer by targeting AUF1.

Many circular RNAs (circRNAs) are reported to be abnormally expressed during the progression of various tumors, and these circRNAs can be used as anti-tumor targets. Therefore, it is important to identify circRNAs that can be used effectively for the clinical diagnosis and treatment of colorectal cancer (CRC). Here, we report that hsa_Circ_0000826 (Circ_0000826), a circRNA with significantly reduced expression level in CRC tissues, is associated with a poor prognosis in patients. The silencing of Circ_0000826 promotes the proliferation of CRC cells. Conversely, the overexpression of Circ_0000826 restricted CRC cell proliferation both in vitro and in vivo. Furthermore, Circ_0000826 could target AU-rich element RNA-binding protein 1 (AUF1). AUF1, known as heterogeneous nuclear ribonucleoprotein D (hnRNP D), could bind to the c-MYC 3'-UTR and promote c-MYC expression. When Circ_0000826 binds to AUF1, it competitively inhibits the binding of AUF1 to the c-MYC 3'-UTR, which inhibits the c-MYC expression and cell proliferation. These results provide novel insights into the functional mechanism of Circ_0000826 action in CRC progression and indicate its potential use as a therapeutic target in CRC.

FMR1 promotes the progression of colorectal cancer cell by stabilizing EGFR mRNA in an m6A-dependent manner.

FMR1, a new m6A reader, is known to be involved in the regulation of cancer progression. However, its role, regulatory mechanism, and clinical significance in colorectal cancer (CRC) are elusive. Here, we showed that FMR1 was upregulated in CRC, and it promoted proliferation and metastasis of CRC cells in vitro and in vivo. Mechanically, FMR1 recognized the m6A-modification site in EGFR mRNA, a key molecule in cancer occurrence and targeted therapy, sustained its stability and maintained its expression in an m6A-dependent manner, thereby promoting the tumorigenesis and metastasis of CRC. And the effect of FMR1 knockdown in CRC cells could be abolished by METTL3. Furthermore, FMR1 shRNA plasmid carried by attenuated Salmonella has an effective anti-tumor effect in vivo. Collectively, we identified the METTL3/FMR1/EGFR axis in the progression of CRC. This novel mechanism indicated that the METTL3/FMR1/EGFR axis is a potential target for early therapeutic intervention in CRC progression.

Changes in diaphragm contractility in cigarette smoking-exposed and smoking cessation rats are associated with alterations in mitochondrial morphology and homeostasis.

The effects of cigarette smoking (CS) cessation on the diaphragm are unknown, as are the CS-induced diaphragmatic mitochondrial changes. We examined the changes in diaphragm contractility, as well as alterations in mitochondrial morphology, function and homoeostasis during CS exposure and after cessation. Rats were randomly divided into CS exposure and CS cessation groups: 3-month CS (S3), 6-month CS (S6), 6-month CS followed by 3-month cessation (S6N3). The changes in the diaphragm were investigated, including contractile properties, the ultrastructure, mitochondrial function and the expression of markers of mitochondrial homoeostasis. CS caused irreversible histological disruption and functional depression in the lungs, along with significantly declines in diaphragmatic contractility and more severely in extensor digitorum longus muscular contractility. Such declines were recovered after 3-month CS cessation. CS exposure disrupted the diaphragmatic mitochondrial morphology and function (S6), which was significantly alleviated in the S6N3 group. The mitochondrial homoeostasis was depressed (S6), as indicated by the downregulation of Pink1 and Mfn1. Interestingly, the Mfn1 level was recovered after smoking cessation (S6N3). In conclusion, smoking cessation eased CS-induced diaphragmatic dysfunction and mitochondrial deregulation, which are likely associated with deregulated mitochondrial homoeostasis.

Biofunctional peptide-click PEG-based hydrogels as 3D cell scaffolds for corneal epithelial regeneration.

Poly(ethylene glycol) (PEG)-based hydrogels as highly promising 3D cell scaffolds have been widely implemented in the field of tissue regrowth and regeneration, yet the functionalized PEG hydrogel providing dynamic, cell-instructive microenvironments is inherently difficult to obtain. Here, we have exploited the specificity of click reaction to develop a set of hydrogels based on 4-arm PEG tetraazide (4-arm-PEG-N3) and di-propargylated peptides (GRGDG and GRDGG) with tunable physicochemical properties applicable for 3D cell scaffolds. The azide groups of PEG were reacted with the alkynyl groups of peptides, catalyzed by copper to form triazole rings, thus generating a cross-linked hydrogel. The gelation time and mechanical strength of the hydrogels varied according to the PEG/peptide feed ratio. The resulting hydrogel exhibited a typical porous microstructure and suitable swelling behavior. The in vitro cytotoxicity test indicated that the resulting hydrogels did not cause apparent cytotoxicity against human corneal epithelial cells (HCECs). After co-incubation with HCECs, the density of RGD as well as peptide sequence in the hydrogels remarkably affected the cell attachment, spreadability, and proliferation. Additionally, the proposed hydrogel showed high ocular biocompatibility after being embedded subconjunctivally into rabbit eyes. Overall, these findings highlighted that the biofunctional hydrogels formed by PEG and RGD motifs via a controllable click reaction might be promising 3D cell scaffolds for corneal epithelial regeneration.

The Landscape of the Tumor-Infiltrating Immune Cell and Prognostic Nomogram in Colorectal Cancer.

Tumor-infiltrating immune cells are associated with prognosis and immunotherapy targets in colorectal cancer (CRC). The recently developed CIBERSORT method allows immune cell analysis by deconvolution of high-throughput data onto gene expression. In this study, we analyzed the relative proportions of immune cells in GEO (94 samples) and TCGA (522 samples) CRC data based on the CIBERSORT method. A total of 22 types of tumor-infiltrating immune cells were evaluated. Combined with GEO and TCGA data, it was found that naive B cells, M2 macrophages, and resting mast cells were highly expressed in normal tissues, while M0 macrophages, M1 macrophages, activated mast cells, and neutrophils were highly expressed in tumors. Moreover, we constructed a prognostic model by infiltrating immune cells that showed high specificity and sensitivity in both the training (AUC of 5-year survival = 0.699) and validation (AUC of 5-year survival = 0.844) sets. This provides another basis for clinical prognosis. The results of multiple immunofluorescence detection showed that there were differences in the results of bioinformatics analysis. Neutrophils were highly expressed in normal tissues, and M2 macrophages were highly expressed in tumor tissues. Collectively, our data suggested that infiltrating immune cells in CRC may be an important determinant of prognosis and immunotherapy.

Enzyme-instructed self-assembly of peptide-drug conjugates in tear fluids for ocular drug delivery.

In vivo self-assembly of small molecules offers an excellent opportunity for targeted and long-term accumulation of a therapeutic agent at the lesion site. Here we demonstrate the strategy of enzyme-instructed self-assembly (EISA) by designing a phosphorylated peptide-drug (IBF-HYD-GFFpY) precursor through the ester bond to release active drugs at the target site. Meanwhile, the in vivo assembly can be achieved by the catalysis of alkaline phosphatase (ALP) in the tear fluid for ocular drug delivery efficiently. The in vitro enzymatic experiments indicate that the dephosphorylation of IBF-HYD-GFFpY occurs firstly with the yield of IBF-HYD-GFFY which subsequently self-assembles into the supramolecular hydrogel to afford sustained drug release over 96 h. In the treatment of lipopolysaccharide (LPS)-activated Raw 264.7 macrophages, IBF-HYD-GFFpY exerts the more potent anti-inflammatory efficacy than that of free ibuprofen (IBF) at the concentration of 200 µM. Moreover, the aqueous solution of IBF-HYD-GFFpY via topical instillation hardly causes ocular irritation, and displays longer precorneal retention compared to the conventional eye drop formulation. In addition, in the in vivo study, a rabbit model of endotoxin-induced uveitis (EIU) evidences the comparable therapeutic efficacy of IBF-HYD-GFFpY eye drops with that of clinically used 0.1 wt% diclofenac (DIC) sodium eye drops by the reduction of macrophage and leukocyte influx. This work, in situ EISA in the tear microenvironment directing in vivo self-assembly of small molecules, may guide a powerful approach for developing enzymatic self-assembled molecules as an efficient delivery system of ocular drugs.

Spatiotemporal Flexible Sparse Reconstruction for Rapid Dynamic Contrast-Enhanced MRI.

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is a tissue perfusion imaging technique. Some versatile free-breathing DCE-MRI techniques combining compressed sensing (CS) and parallel imaging with golden-angle radial sampling have been developed to improve motion robustness with high spatial and temporal resolution. These methods have demonstrated good diagnostic performance in clinical setting, but the reconstruction quality will degrade at high acceleration rates and overall reconstruction time remains long. In this paper, we proposed a new parallel CS reconstruction model for DCE-MRI that enforces flexible weighted sparse constraint along both spatial and temporal dimensions. Weights were introduced to flexibly adjust the importance of time and space sparsity, and we derived a fast-thresholding algorithm which was proven to be simple and efficient for solving the proposed reconstruction model. Results on both the brain tumor DCE and liver DCE show that, at relatively high acceleration factor of fast sampling, lowest reconstruction error and highest image structural similarity are obtained by the proposed method. Besides, the proposed method achieves faster reconstruction for liver datasets and better physiological measures are also obtained on tumor images.

Syntaxin 2 promotes colorectal cancer growth by increasing the secretion of exosomes.

Background: Colorectal cancer (CRC) is one of the most common cancers with high mortality worldwide. Uncontrolled growth is an important hallmark of CRC. However, the mechanisms are poorly understood. Methods: Syntaxin 2 (STX2) expression was analyzed in 160 cases of paraffin-embedded CRC tissue by immunohistochemistry, in 10 cases of fresh CRC tissue by western blot, and in 2 public databases. Gain- and loss-of-function analyses were used to investigate the biological function of STX2 in CRC growth. Exosomes isolation, characterization, Co-immunoprecipitation (Co-IP), flow cytometry and fluorescence were conducted to study the molecular mechanism of STX2 in CRC growth. Results: The expression of STX2 was obviously up-regulated in human CRC tissues. Overexpression of STX2 increased the growth of CRC cells in vitro and in vivo. Downregulation of STX2 repressed the growth of CRC. STX2 modulated exosomes secretion of CRC cells which might correlated with Rab8a expression. The secreted exosomes could be ingested by CRC cells, and ultimately promoted the growth of CRC by arresting the tumor cells at S phase. Conclusions: Our data provide evidence that STX2 promotes CRC growth by increasing exosomes secretion of CRC cells; And the modulation of STX2 in exosomes secretion correlates with Rab8a. Thus, our study identified a new mechanism of STX2 in CRC growth and may provide a possible strategy for CRC therapy.

RANKL Mediates Muscle Atrophy and Dysfunction in a Cigarette Smoke-induced Model of Chronic Obstructive Pulmonary Disease.

Skeletal muscle dysfunction is one of the important comorbidities of chronic obstructive pulmonary disease (COPD); however, the underlying mechanisms remain largely unknown. RANKL (receptor activator of nuclear factor κB ligand), a key mediator in osteoclast differentiation, was also found to play a role in skeletal muscle pathogenesis. Whether RANKL is involved in COPD-related skeletal muscle dysfunction is as-of-yet unknown. We examined the expression of RANKL/RANK in skeletal muscles from mice exposed to cigarette smoke (CS) for 24 weeks. Grip strength and exercise capacity as well as muscular morphology were evaluated in CS-exposed mice with or without anti-RANKL treatment. The expressions of protein synthesis- or muscle growth-related molecules (IGF-1, myogenin, and myostatin), muscle-specific ubiquitin E3 ligases (MuRF1 and atrogin-1), and the NF-κb inflammatory pathway were also evaluated in skeletal muscles. The effect of CS extract on RANKL/RANK expression and that of exogenous RANKL on the ubiquitin-proteasome pathway in C2C12 myotubes were investigated in vitro. Long-term CS exposure induced skeletal muscle dysfunction and atrophy together with upregulation of RANKL/RANK expression in a well-established mouse model of COPD. RANKL neutralization prevented skeletal muscle dysfunction and atrophy. RANKL inhibition decreased expressions of myostatin and MuRF1/Atrogin1 and suppressed the NF-κb pathway in skeletal muscles from CS-exposed mice. In in vitro experiments with C2C12 myotubes, CS extract induced expression of RANKL/RANK, and exogenous RANKL induced activation of the ubiquitin-proteasome pathway and NF-κb pathway via RANK. Our results revealed an important role of the RANKL/RANK pathway in muscle atrophy induced by CS exposure, suggesting that RANKL may be a potential therapeutic target in COPD-related skeletal muscle dysfunction.

Enterotoxigenic Escherichia coli infection promotes enteric defensin expression via FOXO6-METTL3-m6A-GPR161 signalling axis.

The production of natural antimicrobial peptides has emerged as an important mechanism of innate immunity in animals. Defensins, members of a large family of antimicrobial peptides, have been suggested as effector molecules in host defence against bacteria, fungi, protozoa and enveloped viruses. However, the molecular mechanism underlying defensin upregulation in bacterial infection remains poorly understood. The modification of mRNA by N6-adenosine methylation (m6A) on internal bases influences gene expression in eukaryotes. Here, we show that ß-defensin production triggered by Enterotoxigenic Escherichia coli K88 (E. coli K88) infection is controlled by the cellular m6A methyltransferase METTL3. Adding back with METTL3 robustly stimulated the re-expression of defensin, which further supports the conclusion. Furthermore, using a MeRIP-seq approach, we identified a functional connection between m6A dependent GPR161 signalling and the expression of defensins. Mechanistically, we found that the transcription factor FOXO6 interacted with METTL3 to trigger the transcription of GPR161 and the subsequent regulation of ß-defensin expression. The study has shed light on the mechanisms by which enterotoxigenic Escherichia coli infection promotes enteric defensin expression.

Functional, Ultrastructural, and Transcriptomic Changes in Rat Diaphragms with Different Durations of Cigarette Smoke Exposure.

Aims: The aim of the study was to explore the functional and structural changes of the diaphragm and underlying mechanisms in response to 12 or 24 weeks of cigarette smoke (CS) exposure in rats. Materials and Methods: Rats were exposed to CS to develop a COPD model and the rats exposed to room air served as a control group. Rats were randomly divided into four groups: CS12W, CON12W, CS24W, and CON24W. Pulmonary function, lung histopathology, and the contractile properties and ultrastructure of diaphragm muscle were examined in these rats. The changes of transcriptomic profiling of diaphragm muscle were further compared between CS and control rats by the RNA Seq. Results: Both CS groups showed lower FEV0.3/FVC, elevated mean linear intercept (MLI), and reduced mean alveolar numbers (MAN) vs the control groups. The fatigue index (FI) of the diaphragm muscle from the CS12W group, but not CS24W, was significantly increased. Conversely, the force-frequency curves of the diaphragm muscle from the CS24W group, but not CS12W group, were significantly decreased. Consistently, mitochondrial number density (NA) and volume density (Vv) were increased in the CS12W diaphragm muscle, while being decreased in the CS24W group. Furthermore, the diaphragm transcriptomic profiling results showed that genes regulating cell proliferation and energy metabolic activity were un-regulated and genes regulating protein degradation were down-regulated in the CS12W diaphragm, while CS24W diaphragm showed opposite changes. Conclusion: These observations suggested a transition of diaphragm muscle from initial compensatory to decompensatory changes in function, structure, and gene expression during the development of COPD.