PANDORA-Seq unveils the hidden small noncoding RNA landscape in atherosclerosis of LDL receptor-deficient mice.

Small noncoding RNAs (sncRNAs) play diverse roles in numerous biological processes. While the widely used RNA sequencing (RNA-Seq) method has advanced sncRNA discovery, RNA modifications can interfere with the complementary DNA library construction process, preventing the discovery of highly modified sncRNAs including transfer RNA-derived small RNAs (tsRNAs) and ribosomal RNA-derived small RNAs (rsRNAs) that may have important functions in disease development. To address this technical obstacle, we recently developed a novel PANDORA-Seq (Panoramic RNA Display by Overcoming RNA Modification Aborted Sequencing) method to overcome RNA modification-elicited sequence interferences. To identify novel sncRNAs associated with atherosclerosis development, LDL receptor-deficient (LDLR-/-) mice were fed a low-cholesterol diet or high-cholesterol diet (HCD) for 9 weeks. Total RNAs isolated from the intima were subjected to PANDORA-Seq and traditional RNA-Seq. By overcoming RNA modification-elicited limitations, PANDORA-Seq unveiled an rsRNA/tsRNA-enriched sncRNA landscape in the atherosclerotic intima of LDLR-/- mice, which was strikingly different from that detected by traditional RNA-Seq. While microRNAs were the dominant sncRNAs detected by traditional RNA-Seq, PANDORA-Seq substantially increased the reads of rsRNAs and tsRNAs. PANDORA-Seq also detected 1,383 differentially expressed sncRNAs induced by HCD feeding, including 1,160 rsRNAs and 195 tsRNAs. One of HCD-induced intimal tsRNAs, tsRNA-Arg-CCG, may contribute to atherosclerosis development by regulating the proatherogenic gene expression in endothelial cells. Overall, PANDORA-Seq revealed a hidden rsRNA and tsRNA population associated with atherosclerosis development. These understudied tsRNAs and rsRNAs, which are much more abundant than microRNAs in the atherosclerotic intima of LDLR-/- mice, warrant further investigations.

Identification of common sequence motifs shared exclusively among selectively packed exosomal pathogenic microRNAs during rickettsial infections.

We previously reported that microRNA (miR)23a and miR30b are selectively sorted into exosomes derived from rickettsia-infected endothelial cells (R-ECExos). Yet, the mechanism remains unknown. Cases of spotted fever rickettsioses have been increasing, and infections with these bacteria cause life-threatening diseases by targeting brain and lung tissues. Therefore, the goal of the present study is to further dissect the molecular mechanism underlying R-ECExos-induced barrier dysfunction of normal recipient microvascular endothelial cells (MECs), depending on their exosomal RNA cargos. Infected ticks transmit the rickettsiae to human hosts following a bite and injections of the bacteria into the skin. In the present study, we demonstrate that treatment with R-ECExos, which were derived from spotted fever group R parkeri infected human dermal MECs, induced disruptions of the paracellular adherens junctional protein VE-cadherin, and breached the paracellular barrier function in recipient pulmonary MECs (PMECs) in an exosomal RNA-dependent manner. We did not detect different levels of miRs in parent dermal MECs following rickettsial infections. However, we demonstrated that the microvasculopathy-relevant miR23a-27a-24 cluster and miR30b are selectively enriched in R-ECExos. Bioinformatic analysis revealed that common sequence motifs are shared exclusively among the exosomal, selectively-enriched miR23a cluster and miR30b at different levels. Taken together, these data warrant further functional identification and characterization of a monopartition, bipartition, or tripartition among ACA, UCA, and CAG motifs that guide recognition of microvasculopathy-relevant miR23a-27a-24 and miR30b, and subsequently results in their selective enrichments in R-ECExos.

Adipocyte-Derived PXR Signaling Is Dispensable for Diet-Induced Obesity and Metabolic Disorders in Mice.

Pregnane X receptor (PXR) is a xenobiotic receptor that can be activated by numerous chemicals including endogenous hormones, dietary steroids, pharmaceutical agents, and environmental chemicals. PXR has been established to function as a xenobiotic sensor to coordinately regulate xenobiotic metabolism by regulating the expression of many enzymes and transporters required for xenobiotic metabolism. Recent studies have implicated a potentially important role for PXR in obesity and metabolic disease beyond xenobiotic metabolism, but how PXR action in different tissues or cell types contributes to obesity and metabolic disorders remains elusive. To investigate the role of adipocyte PXR in obesity, we generated a novel adipocyte-specific PXR deficient mouse model (PXRΔAd). Notably, we found that loss of adipocyte PXR did not affect food intake, energy expenditure, and obesity in high-fat diet-fed male mice. PXRΔAd mice also had similar obesity-associated metabolic disorders including insulin resistance and hepatic steatosis as control littermates. PXR deficiency in adipocytes did not affect expression of key adipose genes in PXRΔAd mice. Our findings suggest that adipocyte PXR signaling may be dispensable in diet-induced obesity and metabolic disorders in mice. Further studies are needed to understand the role of PXR signaling in obesity and metabolic disorders in the future. SIGNIFICANCE STATEMENT: The authors demonstrate that deficiency of adipocyte pregnane X receptor (PXR) does not affect diet-induced obesity or metabolic disorders in mice and infers that adipocyte PXR signaling may not play a key role in diet-induced obesity. More studies are needed to understand the tissue-specific role of PXR in obesity.

Anti-CD47 antibody treatment attenuates liver inflammation and fibrosis in experimental non-alcoholic steatohepatitis models.

BACKGROUND & AIMS: With the epidemic burden of obesity and metabolic diseases, nonalcoholic fatty liver disease (NAFLD) including steatohepatitis (NASH) has become the most common chronic liver disease in the western world. NASH may progress to cirrhosis and hepatocellular carcinoma. Currently, no treatment is available for NASH. Therefore, finding a therapy for NAFLD/NASH is in urgent need. Previously we have demonstrated that mice lacking CD47 or its ligand thrombospondin1 (TSP1) are protected from obesity-associated NALFD. This suggests that CD47 blockade might be a novel treatment for obesity-associated metabolic disease. Thus, in this study, the therapeutic potential of an anti-CD47 antibody in NAFLD progression was determined. METHODS: Both diet-induced NASH mouse model and human NASH organoid model were utilized in this study. NASH was induced in mice by feeding with diet enriched with fat, fructose and cholesterol (AMLN diet) for 20 weeks and then treated with anti-CD47 antibody or control IgG for 4 weeks. Body weight, body composition and liver phenotype were analysed. RESULTS: We found that anti-CD47 antibody treatment did not affect mice body weight, fat mass or liver steatosis. However, liver immune cell infiltration, inflammation and fibrosis were significantly reduced by anti-CD47 antibody treatment. In vitro data further showed that CD47 blockade prevented hepatic stellate cell activation and NASH progression in a human NASH organoid model. CONCLUSION: Collectively, these data suggest that anti-CD47 antibody might be a new therapeutic option for obesity-associated NASH and liver fibrosis.

HIV Protein Tat Induces Macrophage Dysfunction and Atherosclerosis Development in Low-Density Lipoprotein Receptor-Deficient Mice.

PURPOSE: HIV infection is consistently associated with an increased risk of atherosclerotic cardiovascular disease, but the underlying mechanisms remain elusive. HIV protein Tat, a transcriptional activator of HIV, has been shown to activate NF-κB signaling and promote inflammation in vitro. However, the atherogenic effects of HIV Tat have not been investigated in vivo. Macrophages are one of the major cell types involved in the initiation and progression of atherosclerosis. We and others have previously revealed the important role of IκB kinase ß (IKKß), a central inflammatory coordinator through activating NF-κB, in the regulation of macrophage functions and atherogenesis. This study investigated the impact of HIV Tat exposure on macrophage functions and atherogenesis. METHODS: To investigate the effects of Tat on macrophage IKKß activation and atherosclerosis development in vivo, myeloid-specific IKKß-deficient LDLR-deficient (IKKßΔMyeLDLR-/-) mice and their control littermates (IKKßF/FLDLR-/-) were exposed to recombinant HIV protein Tat. RESULTS: Exposure to Tat significantly increased atherosclerotic lesion size and plaque vulnerability in IKKßF/FLDLR-/- but not IKKßΔMyeLDLR-/- mice. Deficiency of myeloid IKKß attenuated Tat-elicited macrophage inflammatory responses and atherosclerotic lesional inflammation in IKKßΔMyeLDLR-/- mice. Further, RNAseq analysis demonstrated that HIV protein Tat affects the expression of many atherosclerosis-related genes in vitro in an IKKß-dependent manner. CONCLUSIONS: Our findings reveal atherogenic effects of HIV protein Tat in vivo and demonstrate a pivotal role of myeloid IKKß in Tat-driven atherogenesis.

Administration of adipose stromal vascular fraction attenuates acute rejection in donation after circulatory death rat renal transplantation.

OBJECTIVE: Stem cell therapy represents a new approach to induce immune tolerance in solid organ transplantation. However, the time-consuming process of stem cell expending limits the range of stem cell treatment. Uncultured adipose stromal vascular fraction is considered an attractive cell source for cell-based therapy. This study aimed to evaluate the effect of stromal vascular fraction on the immune system in donation after circulatory death rat renal transplantation. METHODS: Stromal vascular fraction cells and splenocytes were co-cultured to evaluate the effect of stromal vascular fraction on splenocyte proliferation and viability. Sprague-Dawley rats were used as donors. and Wistar rats as recipients to establish a donation after a circulatory death rat renal transplantation model. Warm ischemia time was 5 min. Stromal vascular fraction was administered in the rat model following the intra-arterial route. The spleens and grafts of recipients were harvested on days 1, 3 and 7 post-transplantation for assessing acute rejection, infiltration of inflammatory cells, indoleamine 2, 3-dioxygenase expression and T-cell frequency in the spleen. RESULTS: Stromal vascular fraction could inhibit proliferation and induce apoptosis of splenocytes in vitro (P < 0.05). The administration of stromal vascular fraction could significantly reduce acute rejection and infiltration of CD8+ T cells and mononuclear macrophages in grafts, and increase indoleamine 2, 3-dioxygenase expression (P < 0.05). The frequency of CD8+ T cells decreased, and the frequency of CD25+ Foxp3+ regulatory T cells increased in the spleen of the acute rejection + stromal vascular fraction group on day 7 post-transplantation (P < 0.05). CONCLUSION: Administration of the adipose stromal vascular fraction could attenuate acute rejection in donation after circulatory death renal transplantation by increasing the ratio of regulatory T cells and enhancing indoleamine 2, 3-dioxygenase expression.

Myeloid-specific deficiency of pregnane X receptor decreases atherosclerosis in LDL receptor-deficient mice.

The pregnane X receptor (PXR) is a nuclear receptor that can be activated by numerous drugs and xenobiotic chemicals. PXR thereby functions as a xenobiotic sensor to coordinately regulate host responses to xenobiotics by transcriptionally regulating many genes involved in xenobiotic metabolism. We have previously reported that PXR has pro-atherogenic effects in animal models, but how PXR contributes to atherosclerosis development in different tissues or cell types remains elusive. In this study, we generated an LDL receptor-deficient mouse model with myeloid-specific PXR deficiency (PXRΔMyeLDLR-/-) to elucidate the role of macrophage PXR signaling in atherogenesis. The myeloid PXR deficiency did not affect metabolic phenotypes and plasma lipid profiles, but PXRΔMyeLDLR-/- mice had significantly decreased atherosclerosis at both aortic root and brachiocephalic arteries compared with control littermates. Interestingly, the PXR deletion did not affect macrophage adhesion and migration properties, but reduced lipid accumulation and foam cell formation in the macrophages. PXR deficiency also led to decreased expression of the scavenger receptor CD36 and impaired lipid uptake in macrophages of the PXRΔMyeLDLR-/- mice. Further, RNA-Seq analysis indicated that treatment with a prototypical PXR ligand affects the expression of many atherosclerosis-related genes in macrophages in vitro. These findings reveal a pivotal role of myeloid PXR signaling in atherosclerosis development and suggest that PXR may be a potential therapeutic target in atherosclerosis management.

Low-energy shock wave pretreatment recruit circulating endothelial progenitor cells to attenuate renal ischaemia reperfusion injury.

Low-energy shock wave (LESW) has been recognized as a promising non-invasive intervention to prevent the organs or tissues against ischaemia reperfusion injury (IRI), whereas its effect on kidney injury is rarely explored. To investigate the protective role of pretreatment with LESW on renal IRI in rats, animals were randomly divided into Sham, LESW, IRI and LESW + IRI groups. At 4, 12, 24 hours and 3 and 7 days after reperfusion, serum samples and renal tissues were harvested for performing the analysis of renal function, histopathology, immunohistochemistry, flow cytometry and Western blot, as well as enzyme-linked immunosorbent assay. Moreover, circulating endothelial progenitor cells (EPCs) were isolated, labelled with fluorescent dye and injected by tail vein. The fluorescent signals of EPCs were detected using fluorescence microscope and in vivo imaging system to track the distribution of injected circulating EPCs. Results showed that pretreatment with LESW could significantly reduce kidney injury biomarkers, tubular damage, and cell apoptosis, and promote cell proliferation and vascularization in IRI kidneys. The renoprotective role of LESW pretreatment would be attributed to the remarkably increased EPCs in the treated kidneys, part of which were recruited from circulation through SDF-1/CXCR7 pathway. In conclusion, pretreatment with LESW could increase the recruitment of circulating EPCs to attenuate and repair renal IRI.

Peripheral blood non-canonical small non-coding RNAs as novel biomarkers in lung cancer.

One unmet challenge in lung cancer diagnosis is to accurately differentiate lung cancer from other lung diseases with similar clinical symptoms and radiological features, such as pulmonary tuberculosis (TB). To identify reliable biomarkers for lung cancer screening, we leverage the recently discovered non-canonical small non-coding RNAs (i.e., tRNA-derived small RNAs [tsRNAs], rRNA-derived small RNAs [rsRNAs], and YRNA-derived small RNAs [ysRNAs]) in human peripheral blood mononuclear cells and develop a molecular signature composed of distinct ts/rs/ysRNAs (TRY-RNA). Our TRY-RNA signature precisely discriminates between control, lung cancer, and pulmonary TB subjects in both the discovery and validation cohorts and outperforms microRNA-based biomarkers, which bears the diagnostic potential for lung cancer screening.

Remote Ischemic Preconditioning Ameliorates Renal Fibrosis After Ischemia-Reperfusion Injury via Transforming Growth Factor beta1 (TGF-ß1) Signalling Pathway in Rats.

BACKGROUND The present study was conducted to explore the influence of remote ischemic preconditioning (RIPC) on the adjustment of renal fibrosis after ischemia-reperfusion injury (IRI). MATERIAL AND METHODS Male Sprague-Dawley rats were randomly assigned to 3 groups following right-side nephrectomy: the Sham group (without renal artery clamping), the IRI group (45 min left renal artery clamping), and the RIPC group (rats were treated daily with 3 cycles of 5 min of limb ischemia and 5 min of reperfusion on 3 consecutive days before left renal artery occlusion). After 3 months of reperfusion, the renal function and the extent of tubular injury and renal fibrosis were assessed. The expressions of transforming growth factor beta1 (TGF-ß1), p-Smad2, Smad2, p-Smad3, and Smad3 were also evaluated. RESULTS There was no significant difference in renal function and tubular damage among the 3 groups after 45 min of kidney ischemia followed by 3 months of reperfusion. However, an obvious increase of extracellular matrix components and alpha-SMA could be observed in the kidney tissues of the IRI group, and the changes were significantly ameliorated in rats treated with enhanced RIPC. Compared with the IRI group, the expression of TGF-ß1 and the level of p-Smad2 and p-Smad3 were decreased after the intervention of enhanced RIPC. CONCLUSIONS Enhanced RIPC ameliorated renal fibrosis after IRI in rats, which appears to be associated with inhibition of the TGF-ß1/p-Smad2/3 signalling pathway.

Non-nucleoside reverse transcriptase inhibitor efavirenz activates PXR to induce hypercholesterolemia and hepatic steatosis.

BACKGROUND & AIMS: The most prescribed non-nucleoside reverse transcriptase inhibitor, efavirenz, has been associated with elevated risk of dyslipidemia and hepatic steatosis in HIV-infected patients but the underlying mechanisms remain elusive. Herein, we investigated the role of pregnane X receptor (PXR) in mediating the adverse effects of efavirenz on lipid homeostasis. METHODS: Cell-based reporter assays, primary cell culture, and multiple mouse models including conditional knockout and humanized mice were combined to study the impact of efavirenz on PXR activities and lipid homeostasis in vitro and in vivo. A novel liver-specific Pxr knockout mouse model was also generated to determine the contribution of hepatic PXR signaling to efavirenz-elicited dyslipidemia and hepatic steatosis. RESULTS: We found that efavirenz is a potent PXR-selective agonist that can efficiently activate PXR and induce its target gene expression in vitro and in vivo. Treatment with efavirenz-induced hypercholesterolemia and hepatic steatosis in mice but deficiency of hepatic PXR abolished these adverse effects. Interestingly, efavirenz-mediated PXR activation regulated the expression of several key hepatic lipogenic genes including fatty acid transporter CD36 and cholesterol biosynthesis enzyme squalene epoxidase (SQLE), leading to increased lipid uptake and cholesterol biosynthesis in hepatic cells. While CD36 is a known PXR target gene, we identified a DR-2-type of PXR-response element in the SQLE promoter and established SQLE as a direct transcriptional target of PXR. Since PXR exhibits considerable differences in its pharmacology across species, we also confirmed these findings in PXR-humanized mice and human primary hepatocytes. CONCLUSIONS: The widely prescribed antiretroviral drug efavirenz induces hypercholesterolemia and hepatic steatosis by activating PXR signaling. Activation of PXR should be taken into consideration for patients undergoing long-term treatment with PXR agonistic antiretroviral drugs. LAY SUMMARY: Efavirenz is widely prescribed for HIV-infected patients but has some side effects. It can increase lipid levels in patients' blood and liver. Here we show that efavirenz can activate a unique liver protein called PXR which mediates the adverse effects of efavirenz on lipid levels in mouse models.

Myeloid ß-Catenin Deficiency Exacerbates Atherosclerosis in Low-Density Lipoprotein Receptor-Deficient Mice.

OBJECTIVE: The Wnt/ß-catenin signaling is an ancient and evolutionarily conserved pathway that regulates essential aspects of cell differentiation, proliferation, migration and polarity. Canonical Wnt/ß-catenin signaling has also been implicated in the pathogenesis of atherosclerosis. Macrophage is one of the major cell types involved in the initiation and progression of atherosclerosis, but the role of macrophage ß-catenin in atherosclerosis remains elusive. This study aims to investigate the impact of ß-catenin expression on macrophage functions and atherosclerosis development. APPROACH AND RESULTS: To investigate the role of macrophage canonical Wnt/ß-catenin signaling in atherogenesis, we generated ß-cateninΔmyeLDLR-/- mice (low-density lipoprotein receptor-deficient mice with myeloid-specific ß-catenin deficiency). As expected, deletion of ß-catenin decreased macrophage adhesion and migration properties in vitro. However, deficiency of ß-catenin significantly increased atherosclerotic lesion areas in the aortic root of LDLR-/- (low-density lipoprotein receptor-deficient) mice without affecting the plasma lipid levels and atherosclerotic plaque composition. Mechanistic studies revealed that ß-catenin can regulate activation of STAT (signal transducer and activator of transcription) pathway in macrophages, and ablation of ß-catenin resulted in STAT3 downregulation and STAT1 activation, leading to elevated macrophage inflammatory responses and increased atherosclerosis. CONCLUSIONS: This study demonstrates a critical role of myeloid ß-catenin expression in atherosclerosis by modulating macrophage inflammatory responses.

Myeloid-specific deletion of thrombospondin 1 protects against inflammation and insulin resistance in long-term diet-induced obese male mice.

Thrombospondin 1 (TSP1) is a multifunctional matricellular protein. Recent studies demonstrate that TSP1 is highly expressed in adipose tissue (AT) and positively associated with AT inflammation and insulin resistance (IR). In this study, the contribution of different cellular sources of TSP1 to obesity-induced metabolic complications is determined by using mice with either adipocyte or myeloid/macrophage-specific deletion of TSP1 in a diet-induced obese model. The results demonstrated that neither adipocyte nor myeloid/macrophage-specific deletion of TSP1 affected the development of long-term high-fat diet-induced obesity. Adipocyte-specific deletion of TSP1 did not protect mice from obesity-induced inflammation and IR. On the contrary, obese mice with myeloid/macrophage loss of TSP1 had reduced macrophage accumulation in AT, which was accompanied with reduced inflammation and improved glucose tolerance and insulin sensitivity compared with obese control mice. Reduced macrophage-derived-TGF-ß1 signaling and adipose tissue fibrosis were also observed in long-term high-fat-fed mice with myeloid/macrophage-specific TSP1 deletion. Moreover, in vitro experiments demonstrated an autocrine effect of TSP1-mediated TGF-ß activation in macrophages in obesity. Collectively this study highlights the critical contribution of myeloid/macrophage-derived TSP1 to obesity-associated chronic inflammation and IR, which may serve as a new therapeutic target for metabolic disease.

Novel functions of PXR in cardiometabolic disease.

Cardiometabolic disease emerges as a worldwide epidemic and there is urgent need to understand the molecular mechanisms underlying this chronic disease. The chemical environment to which we are exposed has significantly changed in the past few decades and recent research has implicated its contribution to the development of many chronic human diseases. However, the mechanisms of how exposure to chemicals contributes to the development of cardiometabolic disease are poorly understood. Numerous chemicals have been identified as ligands for the pregnane X receptor (PXR), a nuclear receptor functioning as a xenobiotic sensor to coordinately regulate xenobiotic metabolism via transcriptional regulation of xenobiotic-detoxifying enzymes and transporters. In the past decade, the function of PXR in the regulation of xenobiotic metabolism has been extensively studied by many laboratories and the role of PXR as a xenobiotic sensor has been well-established. The identification of PXR as a xenobiotic sensor has provided an important tool for the study of new mechanisms through which xenobiotic exposure impacts human chronic diseases. Recent studies have revealed novel and unexpected roles of PXR in modulating obesity, insulin sensitivity, lipid homeostasis, atherogenesis, and vascular functions. These studies suggest that PXR signaling may contribute significantly to the pathophysiological effects of many known xenobiotics on cardiometabolic disease in humans. The discovery of novel functions of PXR in cardiometabolic disease not only contributes to our understanding of "gene-environment interactions" in predisposing individuals to chronic diseases but also provides strong evidence to inform future risk assessment for relevant chemicals. This article is part of a Special Issue entitled: Xenobiotic nuclear receptors: New Tricks for An Old Dog, edited by Dr. Wen Xie.

A Molecular Signature of Two Long Non-Coding RNAs in Peripheral Blood Predicts Acute Renal Allograft Rejection.

BACKGROUND/AIMS: Acute rejection (AR) is a major complication post renal transplantation, with no widely-accepted non-invasive biomarker. This study aimed to explore the expression profiles of long non-coding RNAs (lncRNAs) in the peripheral blood (PB) of renal transplant recipients and their potential diagnostic values. METHODS: The genome-wide lncRNA expression profiles were analyzed in 150 PB samples from pediatric and adult renal transplant (PRTx and ARTx) cohorts. The diagnostic performance of differentially expressed lncRNA was determined using receiver operator characteristic curve, with area under the curve (AUC) and 95% confidential interval (CI). Finally, a risk score was constructed with logistical regression model. RESULTS: A total of 162 lncRNAs were found differentially expressed in PRTx cohort, while 163 in ARTx cohort. Among these identified lncRNAs, 23 deregulated accordingly in both cohorts, and could distinguish AR recipients from those without AR. Finally, a risk score with two most significant lncRNAs (AF264622 and AB209021) was generated and exhibited excellent diagnostic performance in both PRTx (AUC:0.829, 95% CI:0.735-0.922) and ARTx cohorts (AUC: 0.889, 95% CI: 0.817-0.960). CONCLUSION: A molecular signature of two lncRNAs in PB could serve as a novel non-invasive biomarker for the diagnosis of AR in both pediatric and adult renal transplant recipients.

Targeting IκB kinase ß in Adipocyte Lineage Cells for Treatment of Obesity and Metabolic Dysfunctions.

IκB kinase ß (IKKß), a central coordinator of inflammation through activation of nuclear factor-κB, has been identified as a potential therapeutic target for the treatment of obesity-associated metabolic dysfunctions. In this study, we evaluated an antisense oligonucleotide (ASO) inhibitor of IKKß and found that IKKß ASO ameliorated diet-induced metabolic dysfunctions in mice. Interestingly, IKKß ASO also inhibited adipocyte differentiation and reduced adiposity in high-fat (HF)-fed mice, indicating an important role of IKKß signaling in the regulation of adipocyte differentiation. Indeed, CRISPR/Cas9-mediated genomic deletion of IKKß in 3T3-L1 preadipocytes blocked these cells differentiating into adipocytes. To further elucidate the role of adipose progenitor IKKß signaling in diet-induced obesity, we generated mice that selectively lack IKKß in the white adipose lineage and confirmed the essential role of IKKß in mediating adipocyte differentiation in vivo. Deficiency of IKKß decreased HF-elicited adipogenesis in addition to reducing inflammation and protected mice from diet-induced obesity and insulin resistance. Further, pharmacological inhibition of IKKß also blocked human adipose stem cell differentiation. Our findings establish IKKß as a pivotal regulator of adipogenesis and suggest that overnutrition-mediated IKKß activation serves as an initial signal that triggers adipose progenitor cell differentiation in response to HF feeding. Inhibition of IKKß with antisense therapy may represent as a novel therapeutic approach to combat obesity and metabolic dysfunctions. Stem Cells 2016;34:1883-1895.

Interaction of thrombospondin1 and CD36 contributes to obesity-associated podocytopathy.

Obesity is associated with podocyte injury and the development of proteinuria. Elevated plasma free fatty acid is one of the characteristics of obesity and has been linked to podocyte dysfunction. However, the mechanisms remain unclear. In the current study, we examined the effect of saturated free fatty acid (FFA) on human podocyte apoptosis and function in vitro. The mechanism and its in vivo relevance were also determined. We found that FFA treatment induced human podocyte apoptosis and dysfunction, which was associated with increased expression of a matricellular protein-thrombospondin1 (TSP1). FFA stimulated TSP1 expression in podocytes at the transcriptional levels through activation of MAPK pathway. Addition of purified TSP1 to cell culture media induced podocyte apoptosis and dysfunction. Tis effect is though a TGF-ß independent mechanism. Moreover, peptide treatment to block TSP1 binding to its receptor-CD36 attenuated FFA induced podocyte apoptosis, suggesting that TSP1/CD36 interaction mediates FFA-induced podocyte apoptosis. Importantly, using a diet-induced obese mouse model, in vivo data demonstrated that obesity-associated podocyte apoptosis and dysfunction were attenuated in TSP1 deficient mice as well as in CD36 deficient mice. Taken together, these studies provide novel evidence that the interaction of TSP1 with its receptor CD36 contributes to obesity--associated podocytopathy.

The association and significance of H3K27me3 and a folate metabolic gene ACat2 in neural tube defects.

AIM: To study the association between the expression of H3K27me3 and ACat2 (a folate metabolic protein), in order to elucidate the protective mechanism of folic acid (FA) in neural tube defects (NTDs). METHODS: Eighteen female SD rats were randomly divided into normal, NTD and FA group. NTD group was induced by all-trans retinoic acid (ATRA) at E10d. FA group was fed with FA supplementation since 2 weeks before pregnancy, followed by ATRA induction. At E15d, FA level in the embryonic neural tube was determined by ELISA. Neural stem cells (NSCs) were isolated. Cell proliferation was compared by CCK-8 assay. The differentiation potency was assessed by immunocytochemical staining. H3K27me3 expression was measured by immunofluorescence method and Western blot. ACat2 mRNA expression was detected by qRT-PCR. RESULTS: Cultured NSCs formed numerous Nestin-positive neurospheres. After 5 days, they differentiated into NSE-positive neurons and GFAP-positive astrocytes. When compared with controls, the FA level in NTD group was significantly lower, the ability of cell proliferation and differentiation was significantly reduced, H3K27me3 expression was increased, and ACat2 mRNA expression was decreased (P <0.05). The intervention of FA notably reversed these changes (P <0.05). H3K27me3 expression was negatively correlated with the FA level (rs = -0.908, P <0.01) and ACat2 level (rs = -0.879, P <0.01) in the neural tube. CONCLUSION: The increased H3K27me3 expression might cause a disorder of folate metabolic pathway by silencing ACat2 expression, leading to reduced proliferation and differentiation of NSCs, and ultimately the occurrence of NTD. FA supplementation may reverse this process.

Neutrophil-derived nanovesicles deliver IL-37 to mitigate renal ischemia-reperfusion injury via endothelial cell targeting.

Renal ischemia-reperfusion injury (IRI) is one of the most important causes of acute kidney injury (AKI). Interleukin (IL)-37 has been suggested as a novel anti-inflammatory factor for the treatment of IRI, but its application is still limited by its low stability and delivery efficiency. In this study, we reported a novel engineered method to efficiently and easily prepare neutrophil membrane-derived vesicles (N-MVs), which could be utilized as a promising vehicle to deliver IL-37 and avoid the potential side effects of neutrophil-derived natural extracellular vesicles. N-MVs could enhance the stability of IL-37 and targetedly deliver IL-37 to damaged endothelial cells of IRI kidneys via P-selectin glycoprotein ligand-1 (PSGL-1). In vitro and in vivo evidence revealed that N-MVs encapsulated with IL-37 (N-MV@IL-37) could inhibit endothelial cell apoptosis, promote endothelial cell proliferation and angiogenesis, and decrease inflammatory factor production and leukocyte infiltration, thereby ameliorating renal IRI. Our study establishes a promising delivery vehicle for the treatment of renal IRI and other endothelial damage-related diseases.