SOCS3 dictates the transition of divergent time-phased events in granulocyte TNF-α signaling

Mesenchymal stem cell-derived exosomal microRNA-367-3p mitigates lower limb ischemia/reperfusion injury in mouse skeletal muscle via EZH2 targeting

OBJECTIVE

This study aimed to investigate the protective effect of bone marrow mesenchymal stem cell-derived exosomes (BMSCs-exo) against lower limb ischemia/reperfusion (I/R) injury-induced pyroptosis in skeletal muscle.

METHODS

A mouse model of lower limb I/R injury was utilized to assess the impact of BMSCs-exo, particularly when loaded with microRNA-367-3p (miR-367-3p), on pyroptosis. Histological examination, wet weight/dry weight ratio measurements, and luciferase assays were employed to elucidate the mechanisms involved.

KEY FINDINGS

BMSCs-exo effectively suppressed pyroptosis in injured skeletal muscle tissue. Loading BMSCs-exo with miR-367-3p enhanced this protective effect by downregulating key pyroptosis-related proteins. Luciferase assays identified enhancer of zeste homolog 2 (EZH2) as a direct target of miR-367-3p in BMSCs-exo.

CONCLUSIONS

BMSCs-exo loaded with miR-367-3p safeguarded mouse skeletal muscle against pyroptosis-induced I/R injury by targeting EZH2. These findings offer valuable insights into potential therapeutic strategies for lower limb I/R injuries, emphasizing the therapeutic potential of BMSCs-exo in mitigating tissue damage caused by pyroptosis.

Varied cellular abnormalities in thin vs. normal endometrium in recurrent implantation failure by single-cell transcriptomics

BACKGROUND

Reduced endometrium thickness and receptivity are two important reasons for recurrent implantation failure (RIF). In order to elucidate differences between these two types of endometrial defects in terms of molecular signatures, cellular interactions, and structural changes, we systematically investigated the single-cell transcriptomic atlas across three distinct groups: RIF patients with thin endometrium (≤ 6 mm, TE-RIF), RIF patients with normal endometrium thickness (≥ 8 mm, NE-RIF), and fertile individuals (Control).

METHODS

The late proliferative and mid-secretory phases of the endometrium were collected from three individuals in the TE-RIF group, two in the NE-RIF group, and three in the control group. The study employed a combination of advanced techniques. Single-cell RNA sequencing (scRNA-seq) was utilized to capture comprehensive transcriptomic profiles at the single-cell level, providing insights into gene expression patterns within specific cell types. Scanning and transmission electron microscopy were employed to visualize ultrastructural details of the endometrial tissue, while hematoxylin and eosin staining facilitated the examination of tissue morphology and cellular composition. Immunohistochemistry techniques were also applied to detect and localize specific protein markers relevant to endometrial receptivity and function.

RESULTS

Through comparative analysis of differentially expressed genes among these groups and KEGG pathway analysis, the TE-RIF group exhibited notable dysregulations in the TNF and MAPK signaling pathways, which are pivotal in stromal cell growth and endometrial receptivity. Conversely, in the NE-RIF group, disturbances in energy metabolism emerged as a primary contributor to reduced endometrial receptivity. Additionally, using CellPhoneDB for intercellular communication analysis revealed aberrant interactions between epithelial and stromal cells, impacting endometrial receptivity specifically in the TE-RIF group.

CONCLUSION

Overall, our findings provide valuable insights into the heterogeneous molecular pathways and cellular interactions associated with RIF in different endometrial conditions. These insights may pave the way for targeted therapeutic interventions aimed at improving endometrial receptivity and enhancing reproductive outcomes in patients undergoing ART. Further research is warranted to validate these findings and translate them into clinical applications for personalized fertility treatments.

TRIAL REGISTRATION

Not applicable.

Integration of machine learning to identify diagnostic genes in leukocytes for acute myocardial infarction patients

BACKGROUND

Acute myocardial infarction (AMI) has two clinical characteristics: high missed diagnosis and dysfunction of leukocytes. Transcriptional RNA on leukocytes is closely related to the course evolution of AMI patients. We hypothesized that transcriptional RNA in leukocytes might provide potential diagnostic value for AMI. Integration machine learning (IML) was first used to explore AMI discrimination genes. The following clinical study was performed to validate the results.

METHODS

A total of four AMI microarrays (derived from the Gene Expression Omnibus) were included in bioanalysis (220 sample size). Then, the clinical validation was finished with 20 AMI and 20 stable coronary artery disease patients (SCAD). At a ratio of 5:2, GSE59867 was included in the training set, while GSE60993, GSE62646, and GSE48060 were included in the testing set. IML was explicitly proposed in this research, which is composed of six machine learning algorithms, including support vector machine (SVM), neural network (NN), random forest (RF), gradient boosting machine (GBM), decision trees (DT), and least absolute shrinkage and selection operator (LASSO). IML had two functions in this research: filtered optimized variables and predicted the categorized value. Finally, The RNA of the recruited patients was analyzed to verify the results of IML.

RESULTS

Thirty-nine differentially expressed genes (DEGs) were identified between controls and AMI individuals from the training sets. Among the thirty-nine DEGs, IML was used to process the predicted classification model and identify potential candidate genes with overall normalized weights > 1. Finally, two genes (AQP9 and SOCS3) show their diagnosis value with the area under the curve (AUC) > 0.9 in both the training and testing sets. The clinical study verified the significance of AQP9 and SOCS3. Notably, more stenotic coronary arteries or severe Killip classification indicated higher levels of these two genes, especially SOCS3. These two genes correlated with two immune cell types, monocytes and neutrophils.

CONCLUSION

AQP9 and SOCS3 in leukocytes may be conducive to identifying AMI patients with SCAD patients. AQP9 and SOCS3 are closely associated with monocytes and neutrophils, which might contribute to advancing AMI diagnosis and shed light on novel genetic markers. Multiple clinical characteristics, multicenter, and large-sample relevant trials are still needed to confirm its clinical value.

High-CBD cannabis extracts inhibit the expression of proinflammatory factors via miRNA-mediated silencing in human small intestinal epithelial cells

The incidence of chronic inflammatory disorders and autoimmune diseases is rapidly growing. To date, the COVID-19 pandemic caused by SARS-CoV-2 has killed over 6,209,000 people globally, while no drug has been proven effective for the disease. Screening natural anti-inflammatory compounds for clinical application has drawn much attention. In this study, we showed that high-CBD cannabis extracts #1, #5, #7, #169, and #317 suppressed the levels of expression of proinflammatory cyclooxygenase 2 (COX2) and increased the expression of the anti-inflammatory suppressor of cytokine signaling 3 (SOCS3) in human small intestinal epithelial cells (HSIEC) in TNFα/IFNγ-triggered inflammation. We revealed that these extracts, with the exception of extract #169, also profoundly attenuated induction of proinflammatory cytokines interleukin-6 (IL-6) and/or IL-8 proteins through miR-760- and miR-302c-3p-mediated silencing. The prevalent components in extracts #1 and #7 influenced the levels of IL-8 both individually as well as in combination with each other. However, the high-dose cannabis extracts displayed an inhibitory effect in the growth of HSIEC cells. These results show that our high-CBD cannabis extracts decrease the levels of proinflammatory molecules COX2, IL-6, and IL-8 via transcriptional suppression or miRNA-mediated silencing, highlighting their potential against COVID-19-associated cytokine storm syndrome.

Dickkopf1 fuels inflammatory cytokine responses

Many human diseases, including cancer, share an inflammatory component but the molecular underpinnings remain incompletely understood. We report that physiological and pathological Dickkopf1 (DKK1) activity fuels inflammatory cytokine responses in cell models, mice and humans. DKK1 maintains the elevated inflammatory tone of cancer cells and is required for mounting cytokine responses following ligation of toll-like and cytokine receptors. DKK1-controlled inflammation derives from cell-autonomous mechanisms, which involve SOCS3-restricted, nuclear RelA (p65) activity. We translate these findings to humans by showing that genetic DKK1 variants are linked to elevated cytokine production across healthy populations. Finally, we find that genetic deletion of DKK1 but not pharmacological neutralization of soluble DKK1 ameliorates inflammation and disease trajectories in a mouse model of endotoxemia. Collectively, our study identifies a cell-autonomous function of DKK1 in the control of the inflammatory response, which is conserved between malignant and non-malignant cells. Additional studies are required to mechanistically dissect cellular DKK1 trafficking and signaling pathways.

Pyroptosis in acute pancreatitis and its therapeutic regulation

Pyroptosis defines a new type of GSDMs-mediated programmed cell death, distinguishes from the classical concepts of apoptosis and necrosis-mediated cell death and is prescribed by cell swelling and membrane denaturation, leading to the extensive secretion of cellular components and low-grade inflammatory response. However, NLRP3 inflammasome activation can trigger its downstream inflammatory cytokines, leading to the activation of pyroptosis-regulated cell death. Current studies reveal that activation of caspase-4/5/11-driven non-canonical inflammasome signaling pathways facilitates the pathogenesis and progression of acute pancreatitis (AP). In addition, a large number of studies have reported that NLRP3 inflammasome-dependent pyroptosis is a crucial player in driving the course of the pathogenesis of AP. Excessive uncontrolled GSDMD-mediated pyroptosis has been implicated in AP. Therefore, the pyroptosis-related molecule GSDMD may be an independent prognostic biomarker for AP. The present review paper summarizes the molecular mechanisms of pyroptotic signaling pathways and their pathophysiological impacts on the progress of AP. Moreover, we briefly present some experimental compounds targeting pyroptosis-regulated cell death for exploring novel therapeutic directions for the treatment and management of AP. Our review investigations strongly suggest that targeting pyroptosis could be an ideal therapeutic approach in AP.

Blocking tumor necrosis factor-α delays progression of chronic obstructive pulmonary disease in rats through inhibiting MAPK signaling pathway and activating SOCS3/TRAF1

The present study was conducted in order to study the detailed molecular mechanism of tumor necrosis factor (TNF)-α in chronic obstructive pulmonary disease (COPD). The rats were treated with cigarette smoke (CS) and lipopolysaccharide (LPS) to establish the COPD model. Next, the changes in lung injury in COPD rats with TNF-α knockdown was tested. Meanwhile, the regulation of TNF-α on MAPK pathway and its downstream molecules (SOCS3/TRAF1) was determined by western blotting. On this basis, the activation of MAPK and inhibition of SOCS3/TRAF1 was also examined. Subsequently, the lung function was tested with the plethysmograph, the cells of bronchoalveolar lavage fluid was counted and classified. Furthermore, lung tissue sections were stained with hematoxylin and eosin to verify whether the treatment of MAPK pathway and downstream molecules affected the effect of TNF-α knockdown on COPD. The present study showed that TNF-α knockdown could alleviate the decrease in the function and inflammatory injury of the lungs of rats with COPD. Western blot analysis verified that TNF-α knockdown could inhibit the activation of MAPK pathway and increase the expression of SOCS3/TRAF1. The following experimental results showed that the relief of lung injury caused by TNF-α knockdown could be deteriorated by activating MAPK pathway. It was also found that the symptom of COPD was decreased following transfection with sh-TNF-α but worsened by SOCS3/TRAF1 knockdown. Overall, TNF-α knockdown inhibited the activation of MAPK pathway and increased the expression of SOCS3/TRAF1, thus delaying the process of COPD.

MiR-324/SOCS3 Axis Protects Against Hypoxia/Reoxygenation-Induced Cardiomyocyte Injury and Regulates Myocardial Ischemia via TNF/NF-κB Signaling Pathway

We aimed at exploring the function of microRNA-324/cytokine signaling 3 (miR-324/SOCS3) axis in hypoxia/reoxygenation (H/R) -induced cardiomyocyte injury and its underlying mechanism. The differential expression genes were analyzed based on the GSE83500 and GSE48060 datasets from the Gene Expression Omnibus (GEO) database. Then, to conduct the function enrichment analysis, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases were used. The upstream regulatory microRNAs (miRNAs) of the identified genes were predicted by miRanda, miRWalk, and TargetScan websites. MiR-324 expression was measured with quantitative real-time polymerase chain reaction (qRT-PCR). The target binding of miR-324 and SOCS3 was established by dual-luciferase reporter assay. Cardiomyocyte proliferation was analyzed by cell counting kit-8 (CCK-8) assay, whereas the apoptosis was investigated via flow cytometry. The expression of TNF pathway-related proteins was detected by western blot analysis. SOCS3 was upregulated in patients with myocardial infarction (MI), and function enrichment analyses proved that SOCS3 was enriched in TNF signaling pathway. Moreover, we found that miR-324 was the upstream regulatory miRNA of SOCS3 and negatively regulated SOCS3 expression. MiR-324 was downregulated in cardiomyocytes with H/R-induced injury, inhibiting cell proliferation. In the H/R model, SOCS3 suppresses cardiomyocyte proliferation, which was recovered by miR-324, and induces cell apoptosis, which was repressed by miR-324 via regulating the expression of cleaved caspase-3 and p P38-MAPK. MiR-324 upregulation decreased the protein levels of TNF-α, p-P65, and p-IκBα in cardiomyocytes that suffered from H/R, which was reversed with SOCS3 overexpression. MiR-324/SOCS3 axis could improve the H/R-induced injury of cardiomyocytes via regulating TNF/NF-κB signaling pathway, and this might provide a new therapy strategy for myocardial ischemia.

Cell Type-Specific Roles of NF-κB Linking Inflammation and Thrombosis

The transcription factor NF-κB is a central mediator of inflammation with multiple links to thrombotic processes. In this review, we focus on the role of NF-κB signaling in cell types within the vasculature and the circulation that are involved in thrombo-inflammatory processes. All these cells express NF-κB, which mediates important functions in cellular interactions, cell survival and differentiation, as well as expression of cytokines, chemokines, and coagulation factors. Even platelets, as anucleated cells, contain NF-κB family members and their corresponding signaling molecules, which are involved in platelet activation, as well as secondary feedback circuits. The response of endothelial cells to inflammation and NF-κB activation is characterized by the induction of adhesion molecules promoting binding and transmigration of leukocytes, while simultaneously increasing their thrombogenic potential. Paracrine signaling from endothelial cells activates NF-κB in vascular smooth muscle cells and causes a phenotypic switch to a “synthetic” state associated with a decrease in contractile proteins. Monocytes react to inflammatory situations with enforced expression of tissue factor and after differentiation to macrophages with altered polarization. Neutrophils respond with an extension of their life span—and upon full activation they can expel their DNA thereby forming so-called neutrophil extracellular traps (NETs), which exert antibacterial functions, but also induce a strong coagulatory response. This may cause formation of microthrombi that are important for the immobilization of pathogens, a process designated as immunothrombosis. However, deregulation of the complex cellular links between inflammation and thrombosis by unrestrained NET formation or the loss of the endothelial layer due to mechanical rupture or erosion can result in rapid activation and aggregation of platelets and the manifestation of thrombo-inflammatory diseases. Sepsis is an important example of such a disorder caused by a dysregulated host response to infection finally leading to severe coagulopathies. NF-κB is critically involved in these pathophysiological processes as it induces both inflammatory and thrombotic responses.

A Novel Derivative of the Natural Product Danshensu Suppresses Inflammatory Responses to Alleviate Caerulein-Induced Acute Pancreatitis

Acute pancreatitis (AP), a common abdominal inflammatory disorder, is characterized by premature intracellular activation of digestive proteases within pancreatic acini and a consecutive systemic inflammatory response. Although the mechanism remains to be fully understood, inflammation is the main cause of pancreatic damage in AP. A novel compound [4-(2-acetoxy-3-((R)-3-(benzylthio)-1-methoxy-1-oxopropan-2-ylamino)-3-oxopropyl)-1,2-phenylene diacetate (DSC)], derived from danshensu, exhibits anti-inflammatory and anti-apoptotic properties in vitro. However, its potential beneficial effect in AP has not been demonstrated. This study aimed to investigate the effects and underlying mechanisms of DSC in experimental AP in mice. We found that DSC suppressed inflammatory responses in AP by inhibiting the activation of nuclear factor-κB (NF-κB), signal transducer and activator of transcription 3 (STAT3) and nucleotide-binding domain leucine-rich repeat containing family, pyrin domain-containing 3 (NLRP3) inflammasome. Furthermore, treatment with DSC modulated the infiltration of neutrophils and the phenotypes of macrophages in mice induced with AP. Interestingly, we found that the expression of nuclear factor-erythroid 2 related factor 2 (Nrf2) and its regulated antioxidant enzyme heme oxygenase-1 (HO-1), which modulate inflammatory activities, was significantly increased in DSC-treated groups. Together, our findings demonstrate that DSC alleviates pancreatic inflammation and damage in AP by inhibiting the activation of NF-κB, STAT3, and NLRP3 inflammasome and modulating immune cell responses.

Catabolic and proinflammatory effects of leptin in chondrocytes are regulated by suppressor of cytokine signaling-3

BACKGROUND

Previous studies provide evidence that adipokine leptin increases production of catabolic and proinflammatory factors in chondrocytes and serves as a link between obesity and osteoarthritis (OA). However, the magnitude of the response to leptin treatment varies greatly between chondrocytes from different donor patients. In the present study, we investigated the regulatory role of suppressor of cytokine signaling-3 (SOCS-3) in the leptin-induced responses in OA cartilage.

METHODS

Cartilage and synovial fluid samples from 97 patients with OA undergoing knee replacement surgery were collected. Cartilage samples were cultured with leptin (10 μg/ml), and the levels of proinflammatory and catabolic factors in synovial fluid and in the cartilage culture media, and SOCS-3 expression in the cartilage were measured. The role of SOCS-3 in leptin signaling was further studied in H4 murine chondrocytes by downregulating SOCS-3 with siRNA.

RESULTS

Leptin-induced expression of matrix metalloproteinases MMP-1, MMP-3, MMP-13, interleukin-6 (IL-6), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were higher in the cartilage samples with low SOCS-3 expression. Accordingly, downregulation of SOCS-3 by siRNA in H4 chondrocytes led to enhanced leptin-induced expression of MMP-3, MMP-13, IL-6 and iNOS. Synovial fluid leptin was associated positively, and cartilage SOCS-3 negatively with synovial fluid levels of MMPs in a multivariate model in obese (body mass index (BMI) >30 kg/m²) but not in non-obese (BMI <30 kg/m²) patients.

CONCLUSIONS

Our results show, for the first time, that SOCS-3 regulates leptin-induced responses in cartilage, and could thus be a future drug target in the treatment or prevention of OA, especially in obese patients.

α-Lipoic Acids Promote the Protein Synthesis of C2C12 Myotubes by the TLR2/PI3K Signaling Pathway

Skeletal muscle protein turnover is regulated by endocrine hormones, nutrients, and inflammation. α-Lipoic acid (ALA) plays an important role in energy homeostasis. Therefore, the aim of this study was to investigate the effects of ALA on protein synthesis in skeletal muscles and reveal the underlying mechanism. ALA (25 μM) significantly increased the protein synthesis and phosphorylation of Akt, mTOR, and S6 in C2C12 myotubes with attenuated phosphorylation of AMPK, Ikkα/β, and eIF2α. Intraperitoneal injection of 50 mg/kg ALA also produced the same results in mouse gastrocnemius. Both the PI3K (LY294002) and mTOR (rapamycin) inhibitors abolished the effects of ALA on protein synthesis in the C2C12 myotubes. However, AICAR (AMPK agonist) failed to block the activation of mTOR and S6 by ALA. ALA increased TLR2 and MyD88 mRNA expression in the C2C12 myotubes. TLR2 knockdown by siRNA almost eliminated the effects of ALA on protein synthesis and the Akt/mTOR pathway in the C2C12 myotubes. Immunoprecipitation data showed that ALA enhanced the p85 subunit of PI3K binding to MyD88. These findings indicate that ALA induces protein synthesis and the PI3K/Akt signaling pathway by TLR2.