Adipose tissue gene expression of CXCL10 and CXCL11 modulates inflammatory markers in obesity: implications for metabolic inflammation and insulin resistance

Circulating small non-coding RNAs are associated with the insulin-resistant and obesity-related type 2 diabetes clusters

AIM

To uncover differences in small non-coding RNAs (sncRNAs) in individuals with type 2 diabetes (T2D) categorized into five clusters based on individual characteristics, which may aid in the identification of those prone to rapid progression.

MATERIALS AND METHODS

In the Hoorn Diabetes Care System (DCS) cohort, participants were clustered by age, body mass index (BMI), and glycated haemoglobin, C-peptide and high-density lipoprotein (HDL) cholesterol levels, yielding severe insulin-deficient diabetes, severe insulin-resistant diabetes (SIRD), mild obesity-related diabetes (MOD), mild diabetes, and mild diabetes with high HDL cholesterol clusters (n = 412). Utilizing plasma sncRNA-sequencing, we identified distinct cluster-specific sncRNAs. Validation was performed in a smaller DCS Hoorn dataset (n = 138). To elucidate their potential functions, we examined tissue expression, identified potential targets or (co-)regulated proteins, conducted gene set enrichment analyses on the targets through Reactome, and examined tissue expression of the (co-)regulated proteins.

RESULTS

The insulin-resistant cluster exhibited aberrant expression of 10 sncRNAs, while the high BMI cluster featured eight differentially expressed sncRNAs. Multiple (co-)regulated proteins were identified for sncRNAs associated with both clusters. Proteins associated with both clusters showed enrichment for metabolism. Proteins that specifically and only associated with the SIRD cluster showed enrichment for immune-related signalling. Furthermore, MOD cluster-specific associated proteins showed enrichment for the complement system.

CONCLUSIONS

Our research showed differential sncRNA levels among type 2 diabetes clusters. This may reflect and could deepen our understanding of molecular mechanisms, in development, progression, and risk factors for each cluster.

Genetic and Epigenetic Associations with Post-Transplant Diabetes Mellitus

Post-transplant diabetes mellitus (PTDM) is a common complication of solid organ transplantation. PTDM prevalence varies due to different diabetes definitions. Consensus guidelines for the diagnosis of PTDM have been published based on random blood glucose levels, glycated hemoglobin (HbA1c), and oral glucose tolerance test (OGTT). The task of diagnosing PTDM continues to pose challenges, given the potential for diabetes to manifest at different time points after transplantation, thus demanding constant clinical vigilance and repeated testing. Interpreting HbA1c levels can be challenging after renal transplantation. Pre-transplant risk factors for PTDM include obesity, sedentary lifestyle, family history of diabetes, ethnicity (e.g., African-Caribbean or South Asian ancestry), and genetic risk factors. Risk factors for PTDM include immunosuppressive drugs, weight gain, hepatitis C, and cytomegalovirus infection. There is also emerging evidence that genetic and epigenetic variation in the organ transplant recipient may influence the risk of developing PTDM. This review outlines many known risk factors for PTDM and details some of the pathways, genetic variants, and epigenetic features associated with PTDM. Improved understanding of established and emerging risk factors may help identify people at risk of developing PTDM and may reduce the risk of developing PTDM or improve the management of this complication of organ transplantation.

Obesity-related Plasma CXCL10 Drives CX3CR1-dependent Monocytic Secretion of Macrophage Migration Inhibitory Factor

Obesity is characterized by excessive body fat accumulation and comorbidities such as diabetes mellitus, cardiovascular disease, and obstructive sleep apnea syndrome (OSAS). Both obesity and OSAS are associated with immune disturbance, alterations of systemic inflammatory mediators, and immune cell recruitment to metabolic tissues. Chemokine CXCL10 is an important regulator of proinflammatory immune responses and is significantly increased in patients with severe obesity. This research project aims to investigate the impact of CXCL10 on human monocytes in patients with obesity. We studied the distribution of the CD14/CD16 monocyte subsets as well as their CX3CR1 expression patterns in whole-blood measurements from 92 patients with obesity and/or OSAS with regard to plasma CXCL10 values and individual clinical parameters. Furthermore, cytokine secretion by THP-1 monocytes in response to CXCL10 was analyzed. Data revealed significantly elevated plasma CXCL10 in patients with obesity with an additive effect of OSAS. CXCL10 was found to drive monocytic secretion of macrophage migration inhibitory factor via receptor protein CX3CR1, which significantly correlated with the individual body mass index. Our data show, for the first time, to our knowledge, that CX3CR1 is involved in alternative CXCL10 signaling in human monocytes in obesity-related inflammation. Obesity is a multifactorial disease, and further investigations regarding the complex interplay between obesity-related inflammatory mediators and systemic immune balances will help to better understand and improve the individual situation of our patients.

Study on Potential Differentially Expressed Genes in Idiopathic Pulmonary Fibrosis by Bioinformatics and Next-Generation Sequencing Data Analysis

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive lung disease with reduced quality of life and earlier mortality, but its pathogenesis and key genes are still unclear. In this investigation, bioinformatics was used to deeply analyze the pathogenesis of IPF and related key genes, so as to investigate the potential molecular pathogenesis of IPF and provide guidance for clinical treatment. Next-generation sequencing dataset GSE213001 was obtained from Gene Expression Omnibus (GEO), and the differentially expressed genes (DEGs) were identified between IPF and normal control group. The DEGs between IPF and normal control group were screened with the DESeq2 package of R language. The Gene Ontology (GO) and REACTOME pathway enrichment analyses of the DEGs were performed. Using the g:Profiler, the function and pathway enrichment analyses of DEGs were performed. Then, a protein-protein interaction (PPI) network was constructed via the Integrated Interactions Database (IID) database. Cytoscape with Network Analyzer was used to identify the hub genes. miRNet and NetworkAnalyst databaseswereused to construct the targeted microRNAs (miRNAs), transcription factors (TFs), and small drug molecules. Finally, receiver operating characteristic (ROC) curve analysis was used to validate the hub genes. A total of 958 DEGs were screened out in this study, including 479 up regulated genes and 479 down regulated genes. Most of the DEGs were significantly enriched in response to stimulus, GPCR ligand binding, microtubule-based process, and defective GALNT3 causes HFTC. In combination with the results of the PPI network, miRNA-hub gene regulatory network and TF-hub gene regulatory network, hub genes including LRRK2, BMI1, EBP, MNDA, KBTBD7, KRT15, OTX1, TEKT4, SPAG8, and EFHC2 were selected. Cyclothiazide and rotigotinethe are predicted small drug molecules for IPF treatment. Our findings will contribute to identification of potential biomarkers and novel strategies for the treatment of IPF, and provide a novel strategy for clinical therapy.

xCT-mediated glutamate excretion in white adipocytes stimulates interferon-γ production by natural killer cells in obesity

Obesity-mediated hypoxic stress underlies inflammation, including interferon (IFN)-γ production by natural killer (NK) cells in white adipose tissue. However, the effects of obesity on NK cell IFN-γ production remain obscure. Here, we show that hypoxia promotes xCT-mediated glutamate excretion and C-X-C motif chemokine ligand 12 (CXCL12) expression in white adipocytes, resulting in CXCR4+ NK cell recruitment. Interestingly, this spatial proximity between adipocytes and NK cells induces IFN-γ production in NK cells by stimulating metabotropic glutamate receptor 5 (mGluR5). IFN-γ then triggers inflammatory activation of macrophages and augments xCT and CXCL12 expression in adipocytes, forming a bidirectional pathway. Genetic or pharmacological inhibition of xCT, mGluR5, or IFN-γ receptor in adipocytes or NK cells alleviates obesity-related metabolic disorders in mice. Consistently, patients with obesity showed elevated levels of glutamate/mGluR5 and CXCL12/CXCR4 axes, suggesting that a bidirectional pathway between adipocytes and NK cells could be a viable therapeutic target in obesity-related metabolic disorders.

Effect of CXCL17 on Subcutaneous Preadipocytes Proliferation in Goats

The presence or absence of subcutaneous adipose accumulation will affect the energy storage, insulation resistance and metabolism of animals. Proliferation and differentiation of preadipocytes play a significant role in lipid deposition. The objective of this study was to clone the goat CXCL17 gene and investigate its potential functions on goat subcutaneous preadipocytes' proliferation by gaining or losing function in vitro. The goat CXCL17 gene was cloned by Reverse Transcription-Polymerase Chain Reaction (RT-PCR) and bioinformatics analysis was performed. The expression of the CXCL17 gene in the different goat tissues and adipocytes at different differentiation stages was detected by real-time fluorescence quantitative PCR (qPCR). The results showed that the cloned sequence of goat CXCL17 gene is 728 bp and the CDS region is 357 bp, encoding 118 amino acids. CXCL17 protein is located in nucleus, cytoplasm, mitochondria and extracellular matrix. Tissue-expression profiles revealed that CXCL17 expressed in all of the examined tissues. In visceral tissues, the highest expression level was found in lung (p < 0.01); in muscle tissues, the highest CXCL17 expression level was found in the longissimus dorsi (p < 0.01) and in adipose tissues, the highest expression level was found in subcutaneous adipose (p <0.01). Compared with those cells before differentiation, CXCL17 expression levels upregulated at 48 h (p < 0.01), 72 h (p < 0.01), 120 h (p < 0.01) and downregulated at 96 h (p < 0.01). Furthermore, the results of crystal violet staining and semi-quantitative assay showed that transfection with 1 μg CXCL17 expression plasmid reduced the cell numbers in vitro. Meanwhile, the expression of CCND1 was significantly decreased. A similar consequence happened after interfering with CXCL17 expression. However, plasmid transfected with 2 μg pEGFPN1-CXCL17 increased the number of cells in vitro. These results suggest that CXCL17 is involved in the proliferation of goat subcutaneous preadipocytes.

Adipose Tissue Caveolin-1 Upregulation in Obesity Involves TNF-α/NF-κB Mediated Signaling

Obesity is characterized by chronic low-grade inflammation. Obese people have higher levels of caveolin-1 (CAV1), a structural and functional protein present in adipose tissues (ATs). We aimed to define the inflammatory mediators that influence CAV1 gene regulation and the associated mechanisms in obesity. Using subcutaneous AT from 27 (7 lean and 20 obese) normoglycemic individuals, in vitro human adipocyte models, and in vivo mice models, we found elevated CAV1 expression in obese AT and a positive correlation between the gene expression of CAV1, tumor necrosis factor-alpha (TNF-α), and the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). CAV1 gene expression was associated with proinflammatory cytokines and chemokines and their cognate receptors (r ≥ 0.447, p ≤ 0.030), but not with anti-inflammatory markers. CAV1 expression was correlated with CD163, indicating a prospective role for CAV1 in the adipose inflammatory microenvironment. Unlike wild-type animals, mice lacking TNF-α exhibited reduced levels of CAV1 mRNA/proteins, which were elevated by administering exogenous TNF-α. Mechanistically, TNF-α induces CAV1 gene transcription by mediating NF-κB binding to its two regulatory elements located in the CAV1 proximal regulatory region. The interplay between CAV1 and the TNF-α signaling pathway is intriguing and has potential as a target for therapeutic interventions in obesity and metabolic syndromes.

Gold Nanobipyramid-Mediated Apoptotic Camouflage of Adipocytes for Obesity Immunotherapy

Obesity treatment is a global public health challenge due to inadequate weight loss and weight regain even after endeavors with multimodal treatments. Considering the abundance of resident macrophages in adipose tissues, precise regulation of the interactions between macrophages and adipocytes may provide chances for immunotherapy of obesity. Herein, inspired by the phagocytosis of macrophages to clear apoptotic cells in homeostasis, an immunotherapy strategy for obesity treatment is proposed for the first time through apoptotic camouflage of adipocytes by _PA Au BPs to activate macrophages for clearance, where _PA Au BPs are gold nanobipyramids engineered with adipose-targeting and apoptotic cell-mimicking functions. During clearance, the macrophage is switched from pro-inflammatory M1 to anti-inflammatory M2, remarkably modulating the immune microenvironment of adipose tissues to prevent weight regain. After inguinal injection with _PA Au BPs, the body weights of obese mice are effectively decreased by 24.4% and can be decreased by 33.3% when combined with photothermal lipolysis, and little weight regain is associated with these treatments. This study demonstrates that the strategy of camouflaging adipocytes with apoptotic features holds great potential for obesity immunotherapy.

Identification of Comorbidities, Genomic Associations, and Molecular Mechanisms for COVID-19 Using Bioinformatics Approaches

Several studies have been done to identify comorbidities of COVID-19. In this work, we developed an analytical bioinformatics framework to reveal COVID-19 comorbidities, their genomic associations, and molecular mechanisms accomplishing transcriptomic analyses of the RNA-seq datasets provided by the Gene Expression Omnibus (GEO) database, where normal and infected tissues were evaluated. Using the framework, we identified 27 COVID-19 correlated diseases out of 7,092 collected diseases. Analyzing clinical and epidemiological research, we noticed that our identified 27 diseases are associated with COVID-19, where hypertension, diabetes, obesity, and lung cancer are observed several times in COVID-19 patients. Therefore, we selected the above four diseases and performed assorted analyses to demonstrate the association between COVID-19 and hypertension, diabetes, obesity, and lung cancer as comorbidities. We investigated genomic associations with the cross-comparative analysis and Jaccard's similarity index, identifying shared differentially expressed genes (DEGs) and linking DEGs of COVID-19 and the comorbidities, in which we identified hypertension as the most associated illness. We also revealed molecular mechanisms by identifying statistically significant ten pathways and ten ontologies. Moreover, to understand cellular physiology, we did protein-protein interaction (PPI) analyses among the comorbidities and COVID-19. We also used the degree centrality method and identified ten biomarker hub proteins (IL1B, CXCL8, FN1, MMP9, CXCL10, IL1A, IRF7, VWF, CXCL9, and ISG15) that associate COVID-19 with the comorbidities. Finally, we validated our findings by searching the published literature. Thus, our analytical approach elicited interconnections between COVID-19 and the aforementioned comorbidities in terms of remarkable DEGs, pathways, ontologies, PPI, and biomarker hub proteins.

Gene Expression Profiling of Peripheral Blood Mononuclear Cells in Type 2 Diabetes: An Exploratory Study

Background and Objectives: Visceral obesity is associated with chronic low-grade inflammation that predisposes to metabolic syndrome. Indeed, infiltration of adipose tissue with immune-inflammatory cells, including 'classical' inflammatory M1 and anti-inflammatory 'alternative' M2 macrophages, causes the release of a variety of bioactive molecules, resulting in the metabolic complications of obesity. This study examined the relative expression of macrophage phenotypic surface markers, cholesterol efflux proteins, scavenger receptors, and adenosine receptors in human circulating peripheral blood mononuclear cells (PBMCs), isolated from patients with type 2 diabetes mellitus (T2DM), with the aim to phenotypically characterize and identify biomarkers for these ill-defined cells. Materials and Methodology: PBMCs were isolated from four groups of adults: Normal-weight non-diabetic, obese non-diabetic, newly diagnosed with T2DM, and T2DM on metformin. The mRNA expression levels of macrophage phenotypic surface markers (interleukin-12 (IL-12), C-X-C motif chemokine ligand 10 (CXCL10), C-C motif chemokine ligand 17 (CCL17), and C-C motif receptor 7 (CCR7)), cholesterol efflux proteins (ATP-binding cassette transporter-1 (ABCA1), ATP binding cassette subfamily G member 1 (ABCG1), and sterol 27-hydroxylase (CYP27A)), scavenger receptors (scavenger receptor-A (SR-A), C-X-C motif ligand 16 (CXCL16), and lectin-like oxidized LDL receptor-1 (LOX-1)), and adenosine receptors (adenosine A2A receptor (A2AR) and adenosine A3 receptor (A3R)) were measured using qRT-PCR. Results: In PBMCs from T2DM patients, the expression of IL-12, CCR7, ABCA1, and SR-A1 was increased, whereas the expression of CXCL10, CCL17, ABCG1,27-hydroxylase, LOX-1, A2AR and A3R was decreased. On the other hand, treatment with the antidiabetic drug, metformin, reduced the expression of IL-12 and increased the expression of 27-hydroxylase, LOX-1, CXCL16 and A2AR. Conclusions: PBMCs in the circulation of patients with T2DM express phenotypic markers that are different from those typically present in adipose tissue M1 and M2 macrophages and could be representative of metabolically activated macrophages (MMe)-like cells. Our findings suggest that metformin alters phenotypic markers of MMe-like cells in circulation.

Dectin-1 as a Potential Inflammatory Biomarker for Metabolic Inflammation in Adipose Tissue of Individuals with Obesity

In obesity, macrophage activation and infiltration in adipose tissue (AT) underlie chronic low-grade inflammation-induced insulin resistance. Although dectin-1 is primarily a pathogen recognition receptor and innate immune response modulator, its role in metabolic syndromes remains to be clarified. This study aimed to investigate the dectin-1 gene expression in subcutaneous AT in the context of obesity and associated inflammatory markers. Subcutaneous AT biopsies were collected from 59 nondiabetic (lean/overweight/obese) individuals. AT gene expression levels of dectin-1 and inflammatory markers were determined via real-time reverse transcriptase-quantitative polymerase chain reaction. Dectin-1 protein expression was assessed using immunohistochemistry. Plasma lipid profiles were measured by ELISA. AT dectin-1 transcripts and proteins were significantly elevated in obese as compared to lean individuals. AT dectin-1 transcripts correlated positively with body mass index and fat percentage (r ≥ 0.340, p ≤ 0.017). AT dectin-1 RNA levels correlated positively with clinical parameters, including plasma C-reactive protein and CCL5/RANTES, but negatively with that of adiponectin. The expression of dectin-1 transcripts was associated with that of various proinflammatory cytokines, chemokines, and their cognate receptors (r ≥ 0.300, p ≤ 0.05), but not with anti-inflammatory markers. Dectin-1 and members of the TLR signaling cascade were found to be significantly associated, suggesting an interplay between the two pathways. Dectin-1 expression was correlated with monocyte/macrophage markers, including CD16, CD68, CD86, and CD163, suggesting its monocytes/macrophage association in an adipose inflammatory microenvironment. Dectin-1 expression was independently predicted by CCR5, CCL20, TLR2, and MyD88. In conclusion, dectin-1 may be regarded as an AT biomarker of metabolic inflammation in obesity.

IFN-γ and LPS Induce Synergistic Expression of CCL2 in Monocytic Cells via H3K27 Acetylation

Background

Overexpression of CCL2 (MCP-1) has been implicated in pathogenesis of metabolic conditions, such as obesity and T2D. However, the mechanisms leading to increased CCL2 expression in obesity are not fully understood. Since both IFN-γ and LPS levels are found to be elevated in obesity and shown to be involved in the regulation of metabolic inflammation and insulin resistance, we investigated whether these two agents could synergistically trigger the expression of CCL2 in obesity.

Methods

Monocytes (Human monocytic THP-1 cells) were stimulated with IFN-γ and LPS. CCL2 gene expression was determined by real-time RT-PCR. CCL2 protein was determined by ELISA. Signaling pathways were identified by using epigenetic inhibitors and STAT1 siRNA. Acetylation of H3K27 was analyzed by Western blotting. The acetylation level of histone H3K27 in the transcriptional initiation region of CCL2 gene was determined by ChIP-qPCR.

Results

Our results show that the co-incubation of THP-1 monocytes with IFN-γ and LPS significantly enhanced the expression of CCL2, compared to treatment with IFN-γ or LPS alone. Similar results were obtained using primary monocytes and macrophages. Interestingly, IFN-γ priming was found to be more effective than LPS priming in inducing synergistic expression of CCL2. Moreover, STAT1 deficiency significantly suppressed this synergy for CCL2 expression. Mechanistically, we showed that IFN-γ priming induced acetylation of lysine 27 on histone 3 (H3K27ac) in THP-1 cells. Chromatin immunoprecipitation (ChIP) assay followed by qRT-PCR revealed increased H3K27ac at the CCL2 promoter proximal region, resulting in stabilized gene expression. Furthermore, inhibition of histone acetylation with anacardic acid suppressed this synergistic response, whereas trichostatin A (TSA) could substitute IFN-γ in this synergy.

Conclusion

Our findings suggest that IFN-γ, in combination with LPS, has the potential to augment inflammation via the H3K27ac-mediated induction of CCL2 in monocytic cells in the setting of obesity.

Differential gene expression in nasal airway epithelium from overweight or obese youth with asthma

BACKGROUND

The mechanisms underlying the known link between overweight/obesity and childhood asthma are unclear. We aimed to identify differentially expressed genes and pathways associated with obesity-related asthma through a transcriptomic analysis of nasal airway epithelium.

METHODS

We compared the whole transcriptome in nasal airway epithelium of youth with overweight or obesity and asthma with that of youth of normal weight and asthma, using RNA sequencing data from a cohort of 235 Puerto Ricans aged 9-20 years (EVA-PR) and an independent cohort of 66 children aged 6-16 years in Pittsburgh (VDKA). Differential expression analysis adjusting for age, sex, sequencing plate number, and sample sorting protocol, and the first five principal components were performed independently in each cohort. Results from the two cohorts were combined in a transcriptome-wide meta-analysis. Gene enrichment and network analyses were performed on top genes.

RESULTS

In the meta-analysis, 29 genes were associated with obesity-related asthma at an FDR-adjusted p <.05, including pro-inflammatory genes known to be differentially expressed in adipose tissue of obese subjects (e.g., CXCL11, CXCL10, and CXCL9) and several novel genes. Functional enrichment analyses showed that pathways for interferon signaling, and innate and adaptive immune responses were down-regulated in overweight/obese youth with asthma, while pathways related to ciliary structure or function were up-regulated. Upstream regulatory analysis predicted significant inhibition of the IRF7 pathway. Network analyses identified "hub" genes like GBP5 and SOCS1.

CONCLUSION

Our transcriptome-wide analysis of nasal airway epithelium identified biologically plausible genes and pathways for obesity-related asthma in youth.

Obesity: A Chronic Low-Grade Inflammation and Its Markers

As the prevalence of obesity continues to rise, the world is facing a major public health concern. Obesity is a complex disease associated with an increase in several inflammatory markers, leading to chronic low-grade inflammation. Of multifactorial etiology, it is often used as a measurement of morbidity and mortality. There remains much unknown regarding the association between obesity and inflammation. This review seeks to compile scientific literature on obesity and its associated inflammatory markers in chronic disease and further discusses the role of adipose tissue, macrophages, B-cells, T-cells, fatty acids, amino acids, adipokines, and hormones in obesity. Data were obtained using PubMed and Google Scholar. Obesity, inflammation, immune cells, hormones, fatty acids, and others were search words used to acquire relevant articles. Studies suggest brown adipose tissue is negatively associated with body mass index (BMI) and body fat percentage. Researchers also found the adipose tissue of lean individuals predominantly secretes anti-inflammatory markers, while in obese individuals more pro-inflammatory markers are secreted. Many studies found that adipose tissue in obese individuals showed a shift in immune cells from anti-inflammatory M2 macrophages to pro-inflammatory M1 macrophages, which was also correlated with insulin resistance. Obese individuals generally present with higher levels of hormones such as leptin, visfatin, and resistin. With obesity on the rise globally, it is predicted that severe obesity will become most common amongst low-income adults, black individuals, and women by 2030, making the need for intervention urgent. Further investigation into the association between obesity and inflammation is required to understand the mechanism behind this disease.

Identification of Pre-Diabetic Biomarkers in the Progression of Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is a major global health issue. The development of T2DM is gradual and preceded by the pre-diabetes mellitus (pre-DM) stage, which often remains undiagnosed. This study aimed to identify novel pre-DM biomarkers in a high-fat diet (HFD)-induced pre-DM mouse model. Male C57BL/6J mice were fed either a chow diet or HFD for 12 weeks. Serum and liver samples were isolated in a time-dependent manner. Semi-quantitative assessment of secretory cytokines was performed by cytokine array analysis, and 13 cytokines were selected for further analysis based on the changes in expression levels in the pre-DM and T2DM stages. HFD-fed mice gained body weight and exhibited high serum lipid, liver enzyme, glucose, and insulin levels during the progression of pre-DM to T2DM. The mRNA expression of inflammatory and lipogenic genes was elevated in HFD-fed mice The mRNA expression of Fc receptor, IgG, low affinity Iib, lectin, galactose binding, soluble 1, vascular cell adhesion molecule 1, insulin-like growth factor binding protein 5, and growth arrest specific 6 was elevated in the pre-DM, which was confirmed by measuring protein levels. Our study identified novel pre-DM biomarkers that may help to delay or prevent the progression of T2DM.

MiR-409-3p targets a MAP4K3-ZEB1-PLGF signaling axis and controls brown adipose tissue angiogenesis and insulin resistance

Endothelial cells (ECs) within the microvasculature of brown adipose tissue (BAT) are important in regulating the plasticity of adipocytes in response to increased metabolic demand by modulating the angiogenic response. However, the mechanism of EC-adipocyte crosstalk during this process is not completely understood. We used RNA sequencing to profile microRNAs derived from BAT ECs of obese mice and identified an anti-angiogenic microRNA, miR-409-3p. MiR-409-3p overexpression inhibited EC angiogenic properties; whereas, its inhibition had the opposite effects. Mechanistic studies revealed that miR-409-3p targets ZEB1 and MAP4K3. Knockdown of ZEB1/MAP4K3 phenocopied the angiogenic effects of miR-409-3p. Adipocytes co-cultured with conditioned media from ECs deficient in miR-409-3p showed increased expression of BAT markers, UCP1 and CIDEA. We identified a pro-angiogenic growth factor, placental growth factor (PLGF), released from ECs in response to miR-409-3p inhibition. Deficiency of ZEB1 or MAP4K3 blocked the release of PLGF from ECs and PLGF stimulation of 3T3-L1 adipocytes increased UCP1 expression in a miR-409-3p dependent manner. MiR-409-3p neutralization improved BAT angiogenesis, glucose and insulin tolerance, and energy expenditure in mice with diet-induced obesity. These findings establish miR-409-3p as a critical regulator of EC-BAT crosstalk by modulating a ZEB1-MAP4K3-PLGF signaling axis, providing new insights for therapeutic intervention in obesity.

Chemically Defined Conditions Mediate an Efficient Induction of Dental Pulp Pluripotent-Like Stem Cells into Hepatocyte-Like Cells

Liver diseases are major causes of morbidity and mortality. Dental pulp pluripotent-like stem cells (DPPSCs) are of a considerable promise in tissue engineering and regenerative medicine as a new source of tissue-specific cells; therefore, this study is aimed at demonstrating their ability to generate functional hepatocyte-like cells in vitro. Cells were differentiated on a collagen scaffold in serum-free media supplemented with growth factors and cytokines to recapitulate liver development. At day 5, the differentiated DPPSC cells expressed the endodermal markers FOXA1 and FOXA2. Then, the cells were derived into the hepatic lineage generating hepatocyte-like cells. In addition to the associated morphological changes, the cells expressed the hepatic genes HNF6 and AFP. The terminally differentiated hepatocyte-like cells expressed the liver functional proteins albumin and CYP3A4. In this study, we report an efficient serum-free protocol to differentiate DPPSCs into functional hepatocyte-like cells. Our approach promotes the use of DPPSCs as a new source of adult stem cells for prospective use in liver regenerative medicine.

Association of chemokines IP-10/CXCL10 and I-TAC/CXCL11 with insulin resistance and enhance leukocyte endothelial arrest in obesity

BACKGROUND AND AIMS

Obesity is a key contributing factor to incidental type 2 diabetes and cardiovascular disease. CXCR3 receptor and its ligands CXCL 10 and 11 are associated with atherosclerosis and cardiovascular disease. The aim of our study was to analyse the role of the CXCR3 ligands on insulin resistance (IR) and endothelial dysfunction in human obesity.

METHODS AND RESULTS

We have studied 45 obese patients (mean age 44 ± 6 years, body mass index 45 ± 9 kg/m²) who were selected for Roux-Y-gastric bypass surgery and 21 non obese control subjects with similar age and gender distribution. We measured by ELISA the circulating levels of the CXCR3 ligands interferon-γ inducible protein 10 (IP-10/CXCL10) and interferon-γ-inducible T-cell alpha chemoattractant (I-TAC/CXCL11). Using an ex vivo procedure with the flow chamber assay, we have investigated the effect of such chemokines on endothelial leukocytes arrest under dynamic conditions. Peripheral blood levels of CXCL10 and CXCL11 were significantly higher in obese subjects than in controls (p < 0.001) and significantly correlated with BMI, waist circunference and HOMA-IR. Obese patients with HOMA-IR index above 75th percentile showed highest increase of circulating CXCL10 and CXCL11 values. Under dynamic flow conditions, the enhanced adhesion of patient leukocytes to TNFα-induced human arterial endothelial cells was partly dependent on CXCR3.

CONCLUSIONS

The study demonstrates that CXCL10 and CXCL11 are associated with IR and enhance leukocyte endothelial arrest in obese subjects. Blockade of CXCR3 signaling might be a new therapeutic approach for the prevention of obesity-associated cardiovascular co-morbidities.

Construction and analysis of the abnormal lncRNA-miRNA-mRNA network in hypoxic pulmonary hypertension

The incidence of hypoxic pulmonary hypertension (HPH) is increasing. Accumulating evidence suggests that long noncoding RNAs (lncRNAs) play an important role in HPH, but the functions and mechanism have yet to be fully elucidated. In the present study, we established a HPH rat model with 8 h of hypoxia exposure (10% O2) per day for 21 days. High-throughput sequencing identified 60 differentially expressed (DE) lncRNAs, 20 DE miRNAs and 695 DE mRNAs in rat lung tissue. qRT-PCR verified the accuracy of the results. The DE mRNAs were significantly enriched in immune response, inflammatory response, leukocyte migration, cell cycle, cellular response to interleukin-1, IL-17 signalling pathway, cytokine-cytokine receptor interaction and Toll-like receptor signalling pathway. According to the theory of competing endogenous RNA (ceRNA) networks, lncRNA-miRNA-mRNA network was constructed by Cytoscape software, 16 miRNAs and 144 mRNAs. The results suggested that seven DE lncRNAs (Ly6l, AABR07038849.2, AABR07069008.2, AABR07064873.1, AABR07001382.1, AABR07068161.1 and AABR07060341.2) may serve as molecular sponges of the corresponding miRNAs and play a major role in HPH.

Short Chain Fatty Acid Acetate Increases TNFα-Induced MCP-1 Production in Monocytic Cells via ACSL1/MAPK/NF-κB Axis

Short-chain fatty acid (SCFA) acetate, a byproduct of dietary fiber metabolism by gut bacteria, has multiple immunomodulatory functions. The anti-inflammatory role of acetate is well documented; however, its effect on monocyte chemoattractant protein-1 (MCP-1) production is unknown. Similarly, the comparative effect of SCFA on MCP-1 expression in monocytes and macrophages remains unclear. We investigated whether acetate modulates TNFα-mediated MCP-1/CCL2 production in monocytes/macrophages and, if so, by which mechanism(s). Monocytic cells were exposed to acetate with/without TNFα for 24 h, and MCP-1 expression was measured. Monocytes treated with acetate in combination with TNFα resulted in significantly greater MCP-1 production compared to TNFα treatment alone, indicating a synergistic effect. On the contrary, treatment with acetate in combination with TNFα suppressed MCP-1 production in macrophages. The synergistic upregulation of MCP-1 was mediated through the activation of long-chain fatty acyl-CoA synthetase 1 (ACSL1). However, the inhibition of other bioactive lipid enzymes [carnitine palmitoyltransferase I (CPT I) or serine palmitoyltransferase (SPT)] did not affect this synergy. Moreover, MCP-1 expression was significantly reduced by the inhibition of p38 MAPK, ERK1/2, and NF-κB signaling. The inhibition of ACSL1 attenuated the acetate/TNFα-mediated phosphorylation of p38 MAPK, ERK1/2, and NF-κB. Increased NF-κB/AP-1 activity, resulting from acetate/TNFα co-stimulation, was decreased by ACSL1 inhibition. In conclusion, this study demonstrates the proinflammatory effects of acetate on TNF-α-mediated MCP-1 production via the ACSL1/MAPK/NF-κB axis in monocytic cells, while a paradoxical effect was observed in THP-1-derived macrophages.

Identification of candidate biomarkers and therapeutic agents for heart failure by bioinformatics analysis

INTRODUCTION

Heart failure (HF) is a heterogeneous clinical syndrome and affects millions of people all over the world. HF occurs when the cardiac overload and injury, which is a worldwide complaint. The aim of this study was to screen and verify hub genes involved in developmental HF as well as to explore active drug molecules.

METHODS

The expression profiling by high throughput sequencing of GSE141910 dataset was downloaded from the Gene Expression Omnibus (GEO) database, which contained 366 samples, including 200 heart failure samples and 166 non heart failure samples. The raw data was integrated to find differentially expressed genes (DEGs) and were further analyzed with bioinformatics analysis. Gene ontology (GO) and REACTOME enrichment analyses were performed via ToppGene; protein-protein interaction (PPI) networks of the DEGs was constructed based on data from the HiPPIE interactome database; modules analysis was performed; target gene-miRNA regulatory network and target gene-TF regulatory network were constructed and analyzed; hub genes were validated; molecular docking studies was performed.

RESULTS

A total of 881 DEGs, including 442 up regulated genes and 439 down regulated genes were observed. Most of the DEGs were significantly enriched in biological adhesion, extracellular matrix, signaling receptor binding, secretion, intrinsic component of plasma membrane, signaling receptor activity, extracellular matrix organization and neutrophil degranulation. The top hub genes ESR1, PYHIN1, PPP2R2B, LCK, TP63, PCLAF, CFTR, TK1, ECT2 and FKBP5 were identified from the PPI network. Module analysis revealed that HF was associated with adaptive immune system and neutrophil degranulation. The target genes, miRNAs and TFs were identified from the target gene-miRNA regulatory network and target gene-TF regulatory network. Furthermore, receiver operating characteristic (ROC) curve analysis and RT-PCR analysis revealed that ESR1, PYHIN1, PPP2R2B, LCK, TP63, PCLAF, CFTR, TK1, ECT2 and FKBP5 might serve as prognostic, diagnostic biomarkers and therapeutic target for HF. The predicted targets of these active molecules were then confirmed.

CONCLUSION

The current investigation identified a series of key genes and pathways that might be involved in the progression of HF, providing a new understanding of the underlying molecular mechanisms of HF.

Ceramide kinase regulates TNF-α-induced immune responses in human monocytic cells

Ceramide kinase (CERK) phosphorylates ceramide to produce ceramide-1-phosphate (C1P), which is involved in the development of metabolic inflammation. TNF-α modulates inflammatory responses in monocytes associated with various inflammatory disorders; however, the underlying mechanisms remain not fully understood. Here, we investigated the role of CERK in TNF-α-induced inflammatory responses in monocytes. Our results show that disruption of CERK activity in monocytes, either by chemical inhibitor NVP-231 or by small interfering RNA (siRNA), results in the defective expression of inflammatory markers including CD11c, CD11b and HLA-DR in response to TNF-α. Our data show that TNF-α upregulates ceramide phosphorylation. Inhibition of CERK in monocytes significantly reduced the secretion of IL-1β and MCP-1. Similar results were observed in CERK-downregulated cells. TNF-α-induced phosphorylation of JNK, p38 and NF-κB was reduced by inhibition of CERK. Additionally, NF-κB/AP-1 activity was suppressed by the inhibition of CERK. Clinically, obese individuals had higher levels of CERK expression in PBMCs compared to lean individuals, which correlated with their TNF-α levels. Taken together, these results suggest that CERK plays a key role in regulating inflammatory responses in human monocytes during TNF-α stimulation. CERK may be a relevant target for developing novel therapies for chronic inflammatory diseases.

Involvement of Interleukin-1 Receptor-Associated Kinase 4 and Interferon Regulatory Factor 5 in the Immunopathogenesis of SARS-CoV-2 Infection: Implications for the Treatment of COVID-19

Interleukin-1 receptor-associated kinase 4 (IRAK4) and interferon regulatory factor 5 (IRF5) lie sequentially on a signaling pathway activated by ligands of the IL-1 receptor and/or multiple TLRs located either on plasma or endosomal membranes. Activated IRF5, in conjunction with other synergistic transcription factors, notably NF-κB, is crucially required for the production of proinflammatory cytokines in the innate immune response to microbial infection. The IRAK4-IRF5 axis could therefore have a major role in the induction of the signature cytokines and chemokines of the hyperinflammatory state associated with severe morbidity and mortality in COVID-19. Here a case is made for considering IRAK4 or IRF5 inhibitors as potential therapies for the "cytokine storm" of COVID-19.

Preconditioning Human Adipose-Derived Stromal Cells on Decellularized Adipose Tissue Scaffolds Within a Perfusion Bioreactor Modulates Cell Phenotype and Promotes a Pro-regenerative Host Response

Cell-based therapies involving the delivery of adipose-derived stromal cells (ASCs) on decellularized adipose tissue (DAT) scaffolds are a promising approach for soft tissue augmentation and reconstruction. Our lab has recently shown that culturing human ASCs on DAT scaffolds within a perfusion bioreactor prior to implantation can enhance their capacity to stimulate in vivo adipose tissue regeneration. Building from this previous work, the current study investigated the effects of bioreactor preconditioning on the ASC phenotype and secretory profile in vitro, as well as host cell recruitment following implantation in an athymic nude mouse model. Immunohistochemical analyses indicated that culturing within the bioreactor increased the percentage of ASCs co-expressing inducible nitric oxide synthase (iNOS) and arginase-1 (Arg-1), as well as tumor necrosis factor-alpha (TNF-α) and interleukin-10 (IL-10), within the peripheral regions of the DAT relative to statically cultured controls. In addition, bioreactor culture altered the expression levels of a range of immunomodulatory factors in the ASC-seeded DAT. In vivo testing revealed that culturing the ASCs on the DAT within the perfusion bioreactor prior to implantation enhanced the infiltration of host CD31⁺ endothelial cells and CD26⁺ cells into the DAT implants, but did not alter CD45⁺F4/80⁺CD68⁺ macrophage recruitment. However, a higher fraction of the CD45⁺ cell population expressed the pro-regenerative macrophage marker CD163 in the bioreactor group, which may have contributed to enhanced remodeling of the scaffolds into host-derived adipose tissue. Overall, the findings support that bioreactor preconditioning can augment the capacity of human ASCs to stimulate regeneration through paracrine-mediated mechanisms.