The Effect of FOXC2-AS1 on White Adipocyte Browning and the Possible Regulatory Mechanism

Obesity has become a worldwide epidemic, and obesity-related problems are becoming more severe in public health. Increasing brown adipose tissue (BAT) mass or/and activity in mice and humans has been demonstrated to help lose weight and improve whole-body metabolism. Studies on the conversion of white adipose tissue (WAT) to BAT under certain conditions have provided new possibilities for treating obesity and the related disorders. It has been established that long non-coding RNAs (lncRNAs) play an important role in the regulation of mouse adipocyte differentiation and thermogenic programs; however, the function and potential mechanism of lncRNA in the process of human white adipocyte browning remains unclear. In the present study, we identified a lncRNA called Forkhead Box C2 antisense RNA 1 (FOXC2-AS1), which was first identified in osteosarcoma, and it was highly expressed in human adipocytes but decreased during the white adipocyte differentiation program. FOXC2-AS1 expression was also induced by the thermogenic agent forskolin. Lentivirus-mediated overexpression of FOXC2-AS1 in human white adipocytes did not affect lipid drop accumulation, but significantly promoted the browning phenotype, as revealed by the increased respiratory capacity and the enhanced protein expression levels of brown adipocyte-specific markers. In contrast, inhibiting FOXC2-AS1 with small interfering RNA led to attenuated thermogenic capacity in human white adipocytes. RNA-sequencing analysis and western blot were used to identify a possible regulatory role of the autophagy signaling pathway in FOXC2-AS1 to mediate white-to-brown adipocyte conversion. The autophagy inhibitor 3-methyladenine restored the reduced UCP1 protein level and thermogenic capacity caused by inhibiting FOXC2-AS1. Overall, the present study characterized the potential role of FOXC2-AS1 and further identified a lncRNA-mediated mechanism for inducing browning of human white adipocytes and maintaining thermogenesis, further providing a potential strategy for treating obesity and related disorder.

[Association between platelet-to-lymphocyte ratio and neutrophil-to-lymphocyte ratio with disease activity in Takayasu arteritis patients]

Objective: To explore the relation between platelet-to-lymphocyte ratio (PLR) or neutrophil-to-lymphocyte ratio (NLR) with disease activity in Takayasu arteritis (TA) patients. Methods: Present retrospective study involved 289 patients with TA, who were hospitalized in our department between January 2010 and October 2017, and 280 age and gender matched healthy controls,who underwent thealth examination in our health examination center during the same period (control group). TA patients were further divided into active and inactive groups (180 and 109 cases respectively) according to Kerr scores. The clinical data were compared between groups. Pearson correlation analysis was used to evaluate the relationship between PLR or NLR and disease activity (Kerr score or C-reactive protein or erythrocyte sedimentation rate). Receiver operating characteristic (ROC) curve was employed to judge the cut-off value of disease activity for TA patients. Results: PLR and NLR were significantly higher in TA group than in control group(137.33 (97.38, 193.37) vs. 120.55 (96.86, 144.60) and 2.38 (1.76, 3.57) vs. 1.66 (1.35, 2.08) , respectively, all P<0.001). PLR and NLR were significantly higher in active TA group than in inactive TA group (163.43 (123.64, 224.15) vs. 110.53 (84.22, 147.24) and 2.59 (1.96, 3.94) vs. 1.95 (1.53, 2.86) respectively, all P<0.001). PLR and NLR of active group were significantly decreased after 6 months treatment (164.05 (123.29, 226.29) vs. 104.67 (77.22, 138.43) and 2.58 (1.96, 3.91) vs. 2.15 (1.67, 2.60) respectively, all P<0.001). PLR was positively correlated with Kerr score (r=0.439, P<0.001), C-reactive protein (r=0.328, P<0.001) and erythrocyte sedimentation rate (r=0.410, P<0.001). NLR also exhibited a positive relationship with Kerr score (r=0.235, P<0.001), C-reactive protein (r=0.169, P=0.005) and erythrocyte sedimentation rate (r=0.123, P=0.037). A PLR level of 176.709 was shown to be the best predictive cut-off value for TA disease activity (sensitivity 44.6%, specificity 93.0%, and area under the curve=0.766).A NLR level of 2.128 was shown to be the best predictive cut-off value for TA disease activity (sensitivity 70.9%, specificity 47.7%, and area under the curve=0.691). Conclusion: PLR and NLR are useful markers for predicting disease activity of TA patients.

Variants in mitochondrial tRNA gene may not be associated with thyroid carcinoma

Thyroid cancer is a very common form of endocrine system malignancy. To date, the molecular mechanism underlying thyroid cancer remains poorly understood. Studies of oncocytic tumors have led to a hypothesis which proposes that defects in oxidative phosphorylation (OX- PHOS) may result in a compensatory increase in mitochondrial replication and gene expression. As a result, mitochondrial DNA (mtDNA) mutation analysis has become a useful tool to explore the molecular basis of this disease. Among these mutations, mitochondrial transfer RNAs (mttRNAs) are the hot spots for pathogenic mutations associated with thyroid cancer. However, due to its high mutation rate, the role of mt-tRNA variants in thyroid cancer is still controversial. To address this problem, in this study, we reassessed seven reported mt-tRNA variants: tRNA^Asp G7521A, tRNA^Arg T10411C and T10463C, tRNA^Leu(CUN) A12308G, tRNA^Ile G4292C and C4312T, and tRNA^Ala T5655C, in clinical manifestations of thyroid cancer. We first performed the phylogenetic conservation analysis for these variants; moreover, we used a bioinformatic tool to compare the minimum free energy (G) of mt-tRNA with and without mutations. Most strikingly, none of these variants caused the significant change of the G between the wild-type and the mutant form, suggesting that they may not play an important roles in thyroid cancer. In addition, we screened the frequency of the “pathogenic” A12308G alternation in 300 patients with thyroid cancer and 200 healthy controls. We found that there were five patients and three control subjects carrying this variant. It seemed that the A12308G variant may be a common polymorphism in the human population. Taken together, our study indicated that variants in mt-tRNA genes may not play active roles in patients with thyroid cancer.

[Follistatin-like 1-engineered mesenchymal stem cells prevent myocardial ischemic reperfusion injury]

OBJECTIVE

To investigate the role of follistatin-like protein 1 (FSTL1) on bone marrow mesenchymal stem cells (BM-MSCs)-mediated cardioprotection during myocardial ischemia/reperfusion injury.

METHODS

Rat bone marrow mesenchymal stem cells were isolated by whole bone marrow adherence method in vitro. A total of 60 Wistar rats were randomly divided into 4 groups: control group, ischemic /reperfusion injury (IRI) group, ischemia/reperfusion injury group treated with natural BM-MSCs (IRI+ MSC group), ischemia/reperfusion injury group treated with BM-MSCs which did not contain FSTL1 (IRI+ MSC FSTL1 siRNA group). Survival analysis was used to analyze survival time of rats, besides, expression of FSTL1 was detected by Western blotting. Myocardial pathological changes were detected by Hematoxylin and Eosin (HE) staining. Terminal-deoxynucleoitidyl transferase mediated nick end labeling (TUNEL) and enzyme-linked immunosorbent assay (ELISA) were used to determine the associated biomarkers and apoptosis 7 days after operation.

RESULTS

Compared with IRI group, rats in IRI+ MSC group had a higher survival rate and lived longer. Meanwhile, IRI+ MSC group had higher FSTL1 expression in blood and myocardial tissues than IRI group. Control group showed significantly lower apoptosis rate of myocardial cells[(1.4±0.1)% vs (29.8±4.5)%, P<0.05], less histological changes and infarction areas (0 vs 24.48±4.27, P<0.05) than IRI group. Compared with IRI group, IRI+ MSC group had an improvement of apoptosis rate[(4.2±0.3)% vs (29.8±4.5)%, P<0.05], less histological injury and infarction areas (15.12±3.82 vs 24.48±4.27, P<0.01). IRI+ MSC group had lower expression of LDH, MDA, CK and higher expression of SOD than IRI group (P<0.05). However, IRI+ MSC FSTL1 siRNA group showed weaker protection of myocardial cells than IRI+ MSC group after knockdown of FSTL1 (P<0.05).

CONCLUSION

FSTL1, which was secreted by BM-MSCs, plays a protective role in myocardial IRI.

Mitochondrial ND3 G10398A mutation: a biomarker for breast cancer

Mitochondrial DNA mutations have been found to play important roles in carcinogenesis. The most common G10398A mutation, a non-conservative amino acid substitution from Thr to Ala, seems to be involved in the tumorigenesis of breast cancer. Results from studies concerning this mutation remain inconclusive. In the current study, we first took clinical and molecular datasets from case-control studies to determine the association between the G10398A mutation and breast cancer. We further used the Phylotree to determine the haplogroups of this mutation. The frequencies of this mutation in 500 unrelated healthy controls were also screened. We found that this mutation is very common in the human population, and may be a polymorph.

MiR-146b is a regulator of human visceral preadipocyte proliferation and differentiation and its expression is altered in human obesity

Visceral obesity is an independent risk factor for metabolic syndrome, and abnormal fat accumulation is linked to increases in the number and size of adipocytes. MiR-146b was a miRNA highly expressed in mature adipocytes while very lowly expressed in human mesenchymal stem cells (hMSCs) and human visceral preadipocytes (vHPA). In this paper, we mainly focused on the roles of miR-146b in adipogenesis. We found miR-146b could inhibit the proliferation of visceral preadipocytes and promote their differentiation. MiR-146b in human visceral adipocytes inhibited the expression of KLF7, a member of the Kruppel-like transcription factors, as demonstrated by a firefly luciferase reporter assay, indicating that KLF7 is a direct target of the endogenous miR-146b. MiR-146b expression was significantly altered in visceral and subcutaneous adipose tissues in human overweight and obese subjects, and in the epididymal fat tissues and brown fat tissues of diet-induced obese mice. Our data indicates that miR-146b may be a new therapeutic target against human visceral obesity and metabolic dysfunction.

[Changes of apelin and its receptor in lung tissue of rats with pulmonary hypertension induced by monocrotaline]

OBJECTIVE

To observe the change of apelin and its receptor (APJ) in the lung tissue of rats with pulmonary hypertension induced by monocrotaline and to explore its significance.

METHODS

Twenty-five male SD rats were randomly divided into control group (n = 10) and monocrotaline group (n = 15). On the twenty-first day after the rats were intraperitoneally injected 60 mg/kg monocrotaline for monocrotaline group or equal volume vehicle for control group, the mean pulmonary artery pressure was measured by right heart catheterization. Histopathological study of lung tissue was done with hematoxylin-eosin (HE) and Masson's trichrome staining. The concentration of apelin in the plasma was measured by radioimmunoassay. The expressions of apelin/APJ proteins and genes in lung tissue were measured respectively by Western blot and reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

The mean pulmonary arterial pressure, right ventricular hypertrophy, pulmonary vascular remodeling index, content of apelin protein in lung tissue of monocrotaline group were higher than those in control group. APJ protein and gene expression in monocrotaline group were significantly lower than those in control group (P < 0.01, P < 0.05), but apelin gene expression in the lung tissue between the two groups had no significant difference.

CONCLUSION

Endogenous apelin/APJ dysfunction may play an important role in the development of pulmonary hypertension induced by monocrotaline.