Early identification of lung cancer patients with venous thromboembolism: development and validation of a risk prediction model.

INTRODUCTION: Venous thromboembolism(VTE) is a leading cause of death in patients with lung cancer. Furthermore, hospitalization of patients with advanced lung cancer for VTE treatment represents a major economic burden on the national public health resources. Therefore, we performed this prospective study to identify clinical biomarkers for the early identification of VTE in lung cancer patients. METHODS: This prospective study enrolled 158 patients with confirmed lung cancer, including 27 who were diagnosed with VTE within six months of the follow-up after lung cancer diagnosis. Multivariate logistic regression analysis was used to evaluate the diagnostic performancese of all the relevant clinical features and laboratory indicators in identifying lung cancer patients with a higher risk of VTE. A novel risk prediction model was constructed consisting of five clinical variables with the best diagnostic performances and was validated using the receiver operation characteristic(ROC) curves. The diagnostic performances of the new risk prediction model was also compared with the Khorana risk score (KRS) and the Padua risk score (PRS). RESULTS: The VTE group of lung cancer patients (n = 27) showed significantly higher serum levels of fibrin degradation products (FDP), D-dimer, thrombomodulin (TM), thrombin-antithrombin-complex (TAT), α2-plasmin inhibitor-plasmin Complex (PIC), and tissue plasminogen activator-plasminogen activator inhibitor complex (t-PAIC) compared to those in the non-VTE group (n = 131). ROC curve analyses showed that the diagnostic efficacy of the new VTE risk prediction model with TM ≥ 9.75 TU/ml, TAT ≥ 2.25ng/ml, t-PAIC ≥ 7.35ng/ml, history of VTE, and ECOG PS score ≥ 2 was superior than the KRS and the PRS in the early identification of lung cancer patients with a higher risk of VTE. CONCLUSIONS: The new risk prediction model showed significantly high diagnostic efficacy in the early identification of lung cancer patients with a high risk of VTE. The diagnostic efficacy of the new risk prediction model was higher than the KRS and the PRS in this cohort of lung cancer patients.

Age-Related Changes in Trabecular Bone Score and Bone Mineral Density in Chinese Men: A Cross-Sectional and Longitudinal Study.

Purpose: This study was designed to explore age-related changes in trabecular bone score (TBS) and bone mineral density (BMD) in Chinese men through cross-sectional and longitudinal studies. Patients and Methods: We included adult men who had at least twice TBS and BMD examinations in our hospital between January 2013 and December 2020. All men were divided into an age subgroup per 10 years, comparing differences in baseline lumbar spine (LS) TBS and BMD at various parts between each age group and analyzing age-related changes in TBS and BMD during follow-up. Results: Baseline data showed that in men aged 36 to 85 years, BMD in the hip region showed a decreasing trend with age (P for trend < 0.01). However, TBS reached a high value around the age of 50, after which it decreased with age (P for trend = 0.03). During a mean follow-up of 3 years, the average annual change rate at TBS was -0.17% in men aged 36 to 85 years, with the fastest decrease rate -1.08% at 66 to 75 years (P < 0.05). The mean annual rate of change in LS BMD in different age subgroups increased with age (P for trend = 0.001). There was no significant decrease in mean annual change in BMD in hip regions. Conclusion: In men aged 36~85 years, the trend of TBS was inconsistent with BMD. Men experience a high value of LS TBS around age 50, later than the commonly believed age of peak BMD, which may reflect developmental differences between bone microstructure and bone minerals. The TBS may be used as a better indicator of changes in bone strength than BMD in adult men at short-term follow-up. The rapid loss of TBS at age 66 to 75 may have implications for the prevention and medication of osteoporosis in men.

Advances in the Prediction and Risk Assessment of Lung Cancer-Associated Venous Thromboembolism.

According to the most recent data from the National Cancer Center, venous thromboembolism (VTE) has unsurprisingly become one of the most common complications in lung cancer. VTE not only interferes with the equilibrium of the clotting system but it also affects tumor progression and prognosis. For the identification of high-risk patients, many clinical risk assessment models have been developed and validated based on the risk factors found in previous studies. In this review, we will summarize advances in prediction and risk assessment of VTE, with a focus on early diagnosis and therapy, reduction of mortality, and the burden of medical costs in lung cancer patients.

Colorectal cancer prompted adipose tissue browning and cancer cachexia through transferring exosomal miR-146b-5p.

Cancer cachexia is a complex syndrome that is associated with thermogenic gene regulation. Currently, although some studies have reported the link between exosomes and cancer cachexia in a few types of cancer, the underlying mechanisms remain poorly understood. In this study, we tried to identify whether exosomes derived from colorectal cancer could affect lipolysis in vitro and in vivo. Here, we collected the tissue samples from 48 patients with colorectal cancer (47.91% females and mean age 55 ± 8.20) and 48 healthy people at the First Affiliated Hospital of Nanjing Medical University to detect the miR-146-5p expression. Here, we found that cancer cells released exosomes induced white adipose tissues (WATs) browning and accelerated lipolysis. We also demonstrated that miR-146b-5p was enriched in cancer-related exosomes. Overexpression miR-146b-5p resulted in increased WAT browning, decreased oxygen consumption, and fat mass loss (14.57%). The further study identified that miR-146b-5p could directly repress the downstream gene homeodomain-containing gene C10 (HOXC10), thereby regulating lipolysis. Therefore, our results indicated that cancer cells derived from exosomal miR-146b-5p played an essential role in WAT browning. Inhibition of cancer-related exosomes might be necessary for improving the cachexia condition.

Measurement of BAT activity by targeted molecular magnetic resonance imaging.

OBJECTIVE: The aim of this study was to measure brown adipose tissue (BAT) activity by targeted peptide (CKGGRAKDC-NH2)-coupled, polyethylene glycol (PEG)-coated ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles with magnetic resonance imaging (MRI). METHODS: The peptide was conjugated with PEG-coated USPIO to obtain targeted probes. Male C57BL/6 J mice were randomly divided into cold exposing and control group (n = 5 per group). T2*-weighted images were obtained pre- and post-contrast probes. Histological and gene expression analyses were carried out. RESULTS: T2* relaxation time of BAT in the cold exposing group decreased more significantly compared to the control group. The calculated R2* increased with the reduction of T2* value. The ΔR2* (26.68 s-1) of BAT in the cold exposing group was significantly higher (P < 0.05) than the control group. Iron particle sediments in BAT of the cold exposing group were revealed more than the control group with Prussian blue staining. The UCP1 expression level was up-regulated after cold activation. CONCLUSIONS: BAT activity could be measured in vivo by the targeted peptide-coupled, PEG-coated USPIOs with MRI.

Improvement of intestinal stem cells and barrier function via energy restriction in middle-aged C57BL/6 mice.

This study aimed to reveal the impact of energy restriction on the intestine via structural and molecular changes in terms of intestinal stem cell (ISC) function, ISC niche, intestinal epithelial barrier function, and intestinal immune function. Female C57BL/6J mice, aged 12 months, fed a commercial chow were used in this study. The ISC function, ISC niche, intestinal epithelial barrier function, and intestinal immune function were assessed. Energy restriction reversed aging-induced intestinal shortening and made the crypts shallower. The intestinal epithelial cells isolated from the intestine showed a significant increase in the expression levels of stem cell-associated genes in small intestinal epithelial cells as detected by flow cytometry. Despite the increase in the number of stem cells and the expression levels of markers, no increase or decrease was found in the enteroid complexity of the small intestine and colonic enteroid formation in vitro. The colonic mucous layer was measured in mice of the energy restricted (ER)-treated group to investigate the epithelial barrier function in the colon. The results revealed that the barrier was more complete. The fluorescence intensity of tight junction markers claudin-2 and zonula occludens-1 increased and the mRNA expression profiles of monocyte chemotactic protein 1 and interleukin-6 decreased in the colon of mice in the ER-treated group. The beneficial effects of ER on the colon in terms of the integrity of the mucosal barrier and alleviation of inflammation were confirmed, thus highlighting the importance of modulating the intestinal function in developing effective antiaging dietary interventions.

Long-term exercise-secreted extracellular vesicles promote browning of white adipocytes by suppressing miR-191a-5p.

AIMS: The purpose of the study is to explore the mechanism of transdifferentiation from white adipose tissue (WAT) to Brown adipose tissue (BAT). MATERIALS AND METHOD: In this study, we established a model of mouse obesity induced by a high-fat diet (HFD) before 30 days of forced exercise or sedentary mice. Then, we isolated extracellular vesicles (EVs) from plasma and identified them by transmission electron microscope, dynamic light scattering and western blot analysis. Body temperature and body weight were utilized for assessment of thermogenesis in vivo. Oil red O staining was used to measure triglyceride in vitro. Luciferase reporter assay was applied for the relationship between miR-191a-5p and Prdm16. KEY FINDINGS: As a result, mice that exercised for a long period time exhibited higher caloric expenditure, better weight maintenance and more WAT browning, as well as better resistance to obesity associated with a high-fat diet, compared to mice that lacked exercise. MircoRNA-191-5p (miR-191-5p) was found to be lowly expressed in the EVs from mice with long-term exercise (Exe-EVs). Functional experiments revealed that Exe-EVs promoted WAT browning by the silencing of miR-191-5p. At the molecular level, siRNA-mediated PRDM16 partly inhibited uncoupling protein-1(UCP-1) expression by miR-191-5p inhibitor in white adipocytes. Here, we observed that the lowly expressed miR-191-5p in Exe-EVs promoted the browning of WAT by negatively targeting the PRDM16-3'-untranslated region (PRDM16-3'UTR), thereby enhancing heat production and reducing obesity. SIGNIFICANCE: MiR-191-5p may serve as a potential target for the identification and treatment of obesity.

Low muscle mass impairs fat utilization during light-intensity exercise in Chinese men.

BACKGROUND: Age-related loss of the muscle mass is linked to obesity and diabetes because the muscle is the major site for fat oxidation which is influenced by exercise. We aimed to explore the association between fat oxidation rates (FORs) and exercise intensity during age-related muscle loss. METHODS: A total of 224 healthy Chinese men aged 23-92 years were recruited. Fat and lean tissue masses were measured by DXA. The subjects were also tested using graded incremental exercise with an increased intensity of 10 W until maximal fat oxidation rate (Fatmax) was achieved. Real-time contribution (%) of fat to total energy expenditure were determined using indirect calorimetry. RESULTS: We found that appendicular skeletal muscle mass/weight (ASM/Wt) decreased during ageing and positively correlated with FORs during low-intensity exercise. In multiple linear regression models, FORs was positively related with ASM/Wt (ß =0.446, P=0.0091) but negatively associated with exercise intensity (ß =-0.573, P<0.0001), whereas fat oxidation rate did not show any association with age. Moreover, there was a significantly negative correlation between ASM/Wt and Fatmax. CONCLUSIONS: Our findings highlight the importance of muscle mass in fat utilization during low-intensity exercise. A higher exercise intensity indicated by Fatmax is recommended for improving fat oxidation in Chinese men with decreased muscle mass.

Impact of a high­fat diet on intestinal stem cells and epithelial barrier function in middle­aged female mice.

A high­fat diet (HFD) or obesity­promoting diet is closely associated with metabolic diseases and intestinal tumors, particularly in middle­aged individuals (typically 45­64 years old). The intestinal epithelium constitutes a barrier that separates the host from the food and microbiota in the gut, and thus, a dysfunctional epithelium is associated with a number of diseases. However, the changes caused to the function of intestinal epithelium in response to an HFD have not been well­studied to date. In the present study, middle­aged female mice (12 months old) fed an HFD for a period of 14 weeks were used to determine the effects of HFD on the intestine. Characteristics including the body weight, fat deposition, glucose metabolism, inflammatory state and intestinal morphology were assessed, while the intestinal stem cell (ISC) counts and the ability of isolated intestinal crypts to form organoid bodies in 3D culture were examined. Intestinal epithelial barrier function, including secretory defense, tight junctions and cell apoptosis, were also studied. Morphologically, the HFD resulted in a mild reduction in the length of villi of the small intestine, the colon length and the depth of colon crypts. In addition, the ISC counts were increased in the small intestine and colon in HFD­fed mice. The ability of crypts to grow into organoids (mini­guts) was also increased in crypts obtained from mice fed an HFD, while HFD compromised the epithelial barrier function of the colon. These results demonstrated how an HFD affects the intestinal epithelium and highlighted the need to carefully consider dietary patterns.

MiR-27b-3p Inhibition Enhances Browning of Epididymal Fat in High-Fat Diet Induced Obese Mice.

Objective: Long-term dysregulation of energy balance is the key component of the obesity epidemic. Given the harm of central obesity and the discovery that beige cells appear within white adipose tissue (WAT), enhancing the energy-expending or "browning" ability of visceral adipose tissue (VAT) has become of therapeutic interest. In this study, we focused on the regulating role of microRNA (miRNA)-27b-3p in mice epididymal white adipose tissue (eWAT) browning. Methods: High-fat diet (HFD) induced obese mice model was constructed. Expression of miR-27b-3p and Ucp1 in eWAT was measured during the course of HFD. Through tail vein injection of antimiR-27b-3p, miR-27b-3p expression was inhibited to analyze the potential role of miR-27b-3p in fat browning and metabolism. Results: miR-27b-3p was predominantly expressed in eWAT and browning ability of eWAT in HFD induced obese mice was impaired. Inhibition of miR-27b-3p enhanced browning capacity of eWAT in mice fed an HFD and led to weight loss and insulin sensitivity improvement. Conclusions: High expression of miR-27b-3p in eWAT inhibits browning ability and leads to visceral fat accumulation. It is suggested miR-27b-3p may become a potential therapeutic option for visceral obesity and its associated diseases.

A High Efficient Method to Isolate Exosomes from Small Intestinal Epithelium.

The intestinal epithelium is an important receptor that is not only exposed to nutrients but also to pathogens, such as ingested toxins, bacterial flora, and their metabolites. The sensory information is communicated to extensive endocrine, neural, immune systems, and the exosomes acts as carriers of communication from cell-to-cell. Isolation of exosomes from small intestinal epithelium remains more complex to obtain as a source of exosomes, as it contains varying proportions of exosomes derived from many different cells. Current studies on exosomes have been largely performed using supernatants of cultured cells. This is because, in a cell culture, the origin of exosomes can be determined and isolation of exosomes devoid of 'contaminating' proteins, lipids, and sugars involves relatively simple composition of most culture media facilitates. However, this is hard to achieve in intestinal epithelial cells (IECs) due to several technical issues, including recapitulation of in vivo physiology, operational simplicity, culture stability over time, and assay throughput. Meanwhile, separation of exosomes from a specific cell type remains to be a considerable problem, as the isolated supernatant exosomal fraction may represent only a small fraction of the total instead of reflecting the overall situation. Herein, we proposed an efficient protocol for enrichment of exosomes from the interstitial space of small intestinal epithelium. This method maintains the integrity of the vesicles as well as their contents. Also, it may help to better understand the properties of exosomes and explore their role in cell-to-cell communication of small intestinal epithelium.

Age-associated changes of resting energy expenditure, body composition and fat distribution in Chinese Han males.

Age-related alterations in whole body composition, particularly, reduced fat free mass (FFM) and increased fat mass (FM), lead to a progressive decline in resting energy expenditure (REE). Similarly, regional body composition and fat distribution changes with age might also contribute to an overall lower REE. This study investigated the influence of age on REE, regional body composition and fat distribution, including subcutaneous fat (SF) and visceral fat (VF), in a Chinese Han population as well as their contributions to age-related changes in REE. One hundred and two males aged 31-83 years old underwent dual-energy X-ray absorptiometry (DXA) which measured whole body and regional FM and FFM. SF and VF were measured by magnetic resonance imaging (MRI) and REE by indirect calorimetry. Age was significantly negatively correlated with REE (r = -0.37), total FFM (r = -0.25), upper limbs FFM (r = -0.32), lower limbs FFM (r = -0.34) and showed positive association with trunk FFM (ß=0.926). FM, SF and VF decreased in older age groups after an initial rise up to 55-65 years. REE correlated positively to FM, FFM, SF, VF and showed significant association with age (ß = -0.254) independent of age-associated changes in body composition. The regional alterations in body composition with age were explained by changes in trunk FFM (ß = 0.926). Age-related decline in REE were not solely due to alterations in FM and FFM. Therefore, the changes in regional body composition, fat distribution and REE which occur during aging could be explained by disparities in race, ethnicity, diet, physical activity, and lower specific metabolic rates of FFM components.

Targeted Molecular Magnetic Resonance Imaging Detects Brown Adipose Tissue with Ultrasmall Superparamagnetic Iron Oxide.

The peptide (CKGGRAKDC-NH2) specifically targets the brown adipose tissue (BAT). Here we applied this peptide coupled with polyethylene glycol (PEG)-coated ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles to detect BAT in vivo by magnetic resonance imaging (MRI). The peptide was conjugated with PEG-coated USPIO nanoparticles to obtain targeted USPIO nanoprobes. Then the nanoprobes for BAT were evaluated in mice. T2⁎-weighted images were performed, precontrast and postcontrast USPIO nanoparticles. Finally, histological analyses proved the specific targeting. The specificity of targeted USPIO nanoprobes was observed in mice. The T2⁎ relaxation time of BAT in the targeted group decreased obviously compared to the controls (P<0.001). Prussian blue staining and transmission electron microscope confirmed the specific presence of iron oxide. This study demonstrated that peptide (CKGGRAKDC-NH2) coupled with PEG-coated USPIO nanoparticles could identify BAT noninvasively in vivo with MRI.

11ß-hydroxysteroid dehydrogenase type 1 inhibitor attenuates high-fat diet induced cardiomyopathy.

BACKGROUND: High-fat diet (HFD) induces cardiac hypertrophy; however, the underlying cellular and molecular mechanisms are yet unclear. In the present study, we investigated the roles of 11ß-hydroxysteroid dehydrogenase type 1 (11ß-HSD1), an amplifier of local glucocorticoid activity, in the pathogenesis of cardiac dysfunction. METHODS: Male Wistar rats were fed normal chow diet (NC) or HFD and examined the cardiac remolding and functional alteration by echocardiography and histology. Primary neonatal rat ventricular cardiomyocytes (NRCMs) treated with palmitic acid (PA) or infected by lentivirus were used for identifying the role by 11ß-HSD1 in cardiac hypertrophy. Genome microarray of NRCMs was performed to further reveal the mechanism underlying cardiac dysfunction. RESULTS: Palmitic acid induced hypertrophy in NRCMs that upregulated 11ß-HSD1 expression in cardiomyocytes, which led to a significant enlargement in the cell size and expression of cardiac hypertrophy-specific genes. Conversely, a remarkable decrease in cardiomyocytes size was detected in either BVT.2733 (a selective inhibitor of 11ß-HSD1)-treated or 11ß-HSD1-deficient NRCMs. Furthermore, both glucocorticoid receptor (GR) antagonist RU486 and mineralocorticoid receptor (MR) antagonist spironolactone markedly attenuated the 11ß-HSD1-induced cardiomyocytes hypertrophy. Genome microarray revealed that cAMP and calcium signaling pathways are potential downstream signaling pathways regulated by 11ß-HSD1 in cardiomyocytes hypertrophy. Similar to in vitro results, BVT.2733 strikingly attenuated cardiac hypertrophy and improved cardiac function in HFD-fed rats. CONCLUSION: 11ß-HSD1 acts as an important regulator that controls the cardiac remolding via both GR and MR and the pharmacological inhibition of 11ß-HSD1 could be a new therapeutic approach in preventing HFD-induced cardiac hypertrophy.

MiR-27b-3p Regulation in Browning of Human Visceral Adipose Related to Central Obesity.

OBJECTIVE: Given the rising prevalence of central obesity and the discovery that beige cells appear within white adipose tissue, strategies to enhance these energy-expending adipocytes or "browning" within white adipose depots have become of therapeutic interest to combat obesity and its associated disorders. This study focused on, the role of microRNA (miRNA)-27b-3p in human visceral adipose tissue (VAT) browning. METHODS: Expression of miR-27b-3p and UCP1 in VAT and serum of humans was measured. MiR-27b-3p was overexpressed or suppressed in human visceral stromal fraction cells to analyze the potential role of miR-27b-3p. RESULTS: UCP1 expression in human VAT decreased with elevated BMI and waist-hip ratio, whereas expression of miR-27b-3p was found to correlate positively with BMI and waist-hip ratio. High expression of miR-27b-3p was associated with reduced browning ability of human visceral adipocytes. Antagonism of miR-27b-3p led to the enhancement of browning ability in human visceral adipocytes. CONCLUSIONS: These findings highlight the decreased browning ability of VAT from humans with obesity and the role of miR-27b-3p in regulating browning of human visceral adipocytes. They suggest that miR-27b-3p should be further explored as a potential target for the treatment of central obesity.

Opposing effects on cardiac function by calorie restriction in different-aged mice.

Calorie restriction (CR) increases average and maximum lifespan and exhibits an apparent beneficial impact on age-related diseases. Several studies have shown that CR initiated either in middle or old age could improve ischemic tolerance and rejuvenate the aging heart; however, the data are not uniform when initiated in young. The accurate time to initiate CR providing maximum benefits for cardiac remodeling and function during aging remains unclear. Thus, whether a similar degree of CR initiated in mice of different ages could exert a similar effect on myocardial protection was investigated in this study. C57BL/6 mice were subjected to a calorically restricted diet (40% less than the ad libitum diet) for 3 months initiated in 3, 12, and 19 months. It was found that CR significantly reversed the aging phenotypes of middle-aged and old mice including cardiac remodeling (cardiomyocyte hypertrophy and cardiac fibrosis), inflammation, mitochondrial damage, telomere shortening, as well as senescence-associated markers but accelerated in young mice. Furthermore, whole-genome microarray demonstrated that the AMP-activated protein kinase (AMPK)-Forkhead box subgroup 'O' (FOXO) pathway might be a major contributor to contrasting regulation by CR initiated in different ages; thus, increased autophagy was seen in middle-aged and old mice but decreased in young mice. Together, the findings demonstrated promising myocardial protection by 40% CR should be initiated in middle or old age that may have vital implications for the practical nutritional regimen.

Assessment of Fat distribution and Bone quality with Trabecular Bone Score (TBS) in Healthy Chinese Men.

Whether fat is beneficial or detrimental to bones is still controversial, which may be due to inequivalence of the fat mass. Our objective is to define the effect of body fat and its distribution on bone quality in healthy Chinese men. A total of 228 men, aged from 38 to 89 years, were recruited. BMD, trabecular bone score (TBS), and body fat distribution were measured by dual-energy X-ray absorptiometry. Subcutaneous and visceral fat were assessed by MRI. In the Pearson correlation analysis, lumbar spine BMD exhibited positive associations with total and all regional fat depots, regardless of the fat distribution. However, the correlation disappeared with adjusted covariables of age, BMI, HDL-C, and HbA1c%. TBS was negatively correlated with fat mass. In multiple linear regression models, android fat (and not gynoid, trunk, or limbs fat) showed significant inverse association with TBS (ß = -0.611, P < 0.001). Furthermore, visceral fat was described as a pathogenic fat harmful to TBS, even after adjusting for age and BMI (ß = -0.280, P = 0.017). Our findings suggested that body fat mass, especially android fat and visceral fat, may have negative effects on bone microstructure; whereas body fat mass contributes to BMD through mechanical loading.

Determination of UCP1 expression in subcutaneous and perirenal adipose tissues of patients with hypertension.

The objective of this study is to determine the property of human perirenal adipose tissue (PAT) and assess the adipose property of PAT in hypertension. Ninety-four patients, including 64 normotensive patients (T-NP) and 30 hypertensive patients (HP), who underwent renal surgery were included. Expression analysis was performed using quantitative real-time polymerase chain reaction, Western blot, and immunohistochemistry in PAT and back subcutaneous adipose tissue (bSAT) depots. Compared with bSAT, PAT adipocytes were smaller, and the expressions of uncoupling protein-1 (UCP1) mRNA and protein were markedly higher, while the mRNA expressions of markers for classic beige and white adipocytes were lower in PAT. Immunohistochemistry analysis showed more multilocular UCP1-positive adipocytes in PAT than in bSAT. UCP1 expressions were lower in PAT in HP than in the T-NP or age- and body mass index-matched NP groups. Bigger unilocular adipocytes with less UCP1 staining in PAT were detected in HP than in NP group, although no such difference was observed in bSAT. PAT acts as a brown-like fat. UCP1 expression of PAT was lower in HP than in normotensive patients. UCP1 expression of PAT may serve as a protective indicator for hypertension.

Glucocorticoids transcriptionally regulate miR-27b expression promoting body fat accumulation via suppressing the browning of white adipose tissue.

Long-term glucocorticoid (GC) treatment induces central fat accumulation and metabolic dysfunction. We demonstrate that microRNA-27b (miR-27b) plays a central role in the pathogenesis of GC-induced central fat accumulation. Overexpression of miR-27b had the same effects as dexamethasone (DEX) treatment on the inhibition of brown adipose differentiation and the energy expenditure of primary adipocytes. Conversely, antagonizing miR-27b function prevented DEX suppression of the expression of brown adipose tissue-specific genes. GCs transcriptionally regulate miR-27b expression through a GC receptor-mediated direct DNA-binding mechanism, and miR-27b suppresses browning of white adipose tissue (WAT) by targeting the three prime untranslated region of Prdm16. In vivo, antagonizing miR-27b function in DEX-treated mice resulted in the efficient induction of brown adipocytes within WAT and improved GC-induced central fat accumulation. Collectively, these results indicate that miR-27b functions as a central target of GC and as an upstream regulator of Prdm16 to control browning of WAT and, consequently, may represent a potential target in preventing obesity.

Expression profiling of PPARγ-regulated microRNAs in human subcutaneous and visceral adipogenesis in both genders.

Clinical evidence shows that visceral fat accumulation decreases whereas sc fat increases in patients treated with thiazolidinediones (TZDs), a type of peroxisome proliferator-activated receptor (PPAR)γ agonist. To clarify the molecular mechanism of the differential effects of PPARγ agonists on sc and visceral adipose, we investigated expression profiling of PPARγ-regulated micro-RNAs (miRNAs) using miRNA microarray. The level of 182 miRNAs changed in human sc adipose treated with pioglitazone, whereas only 46 miRNAs changed in visceral adipose. Among these miRNAs, 27 miRNAs changed in both human sc and visceral adipocytes. Specifically, 7 miRNAs changed at the same direction in sc and visceral adipocytes, whereas 20 miRNAs changed at opposite directions in these two fat depots. Bioinformatics analysis showed that these miRNAs and the predicted target genes were involved in TGF-ß-, Wnt/ß-catenin-, and insulin-signaling pathways and related to metabolic regulation or cell cycle. Among the miRNAs changed at the same direction in sc and visceral adipocytes, miR-378, located in the first intron of PPARγ coactivator 1ß (PGC1ß), was coordinately expressed with PGC1ß during adipogenesis. Moreover, miR-378 and PGC1ß were both up-regulated by PPARγ agonist. We also provided evidence that miR-378 promoted adipogenesis in sc fat, but not in visceral fat. These results display miRNAs expression profiling altered in sc and visceral adipogenesis regulated by PPARγ and suggest a potential mechanism underlying the differential effects of TZDs on the 2 fat depot accumulations.