Genetic inactivation of the translin/trax microRNA-degrading enzyme phenocopies the robust adiposity induced by Translin (Tsn) deletion

Adenosine A2A Receptor Regulates microRNA-181b Expression in Aorta: Therapeutic Implications for Large-Artery Stiffness

Background The identification of large-artery stiffness as a major, independent risk factor for cardiovascular disease-associated morbidity and death has focused attention on identifying therapeutic strategies to combat this disorder. Genetic manipulations that delete or inactivate the translin/trax microRNA-degrading enzyme confer protection against aortic stiffness induced by chronic ingestion of high-salt water (4%NaCl in drinking water for 3 weeks) or associated with aging. Therefore, there is heightened interest in identifying interventions capable of inhibiting translin/trax RNase activity, as these may have therapeutic efficacy in large-artery stiffness. Methods and Results Activation of neuronal adenosine A2A receptors (A2ARs) triggers dissociation of trax from its C-terminus. As A2ARs are expressed by vascular smooth muscle cells (VSMCs), we investigated whether stimulation of A2AR on vascular smooth muscle cells promotes the association of translin with trax and, thereby increases translin/trax complex activity. We found that treatment of A7r5 cells with the A2AR agonist CGS21680 leads to increased association of trax with translin. Furthermore, this treatment decreases levels of pre-microRNA-181b, a target of translin/trax, and those of its downstream product, mature microRNA-181b. To check whether A2AR activation might contribute to high-salt water-induced aortic stiffening, we assessed the impact of daily treatment with the selective A2AR antagonist SCH58261 in this paradigm. We found that this treatment blocked aortic stiffening induced by high-salt water. Further, we confirmed that the age-associated decline in aortic pre-microRNA-181b/microRNA-181b levels observed in mice also occurs in humans. Conclusions These findings suggest that further studies are warranted to evaluate whether blockade of A2ARs may have therapeutic potential in treating large-artery stiffness.

The associations between cognitive functions and TSNAX genetic variations in patients with schizophrenia

BACKGROUND

The translin-associated factor X (TSNAX) gene, located adjacent to the DISC1 gene, has been implicated in schizophrenia. While cognitive impairment determines long-term the functional outcome of schizophrenia, the role of TSNAX in cognitive dysfunction of schizophrenia patients remains elusive. This study aimed to explore the genetic effect of TSNAX on cognitive functions of schizophrenia.

METHODS

We recruited 286 chronic schizophrenia patients who had been stabilized with antipsychotics for at least 2 months and genotyped three TSNAX SNPs (rs1630250, rs766288, rs6662926). Clinical symptoms and seven cognitive domains were assessed. The score of cognitive tests was standardized to T score.

RESULTS

Clinical symptoms were similar among genotypes of all the three SNPs. The GLM analysis demonstrated that TSNAX genetic polymorphisms influenced cognitive function of schizophrenia patients after adjustment for gender, age, and education. The patients with the rs1630250 C/G genotype performed better than the G/G homozygotes in the Trail Making A (p = 0.034). Those with the rs766288 G/T genotype also performed better than the G/G homozygotes in the Trail Making A (p = 0.012). The patients with the G/G genotype of rs6662926 also performed better than the C/C homozygotes in verbal learning and memory test (p = 0.044).

CONCLUSIONS

This study suggests that the TSNAX gene variation may influence the cognitive functions of the patients with schizophrenia.

Comparative Proteomic Analysis of tPVAT during Ang II Infusion

Perivascular adipose tissue (PVAT) homeostasis plays an important role in maintaining vascular function, and PVAT dysfunction may induce several pathophysiological situations. In this study, we investigated the effect and mechanism of the local angiotensin II (Ang II) on PVAT. High-throughput comparative proteomic analysis, based on TMT labeling combined with LC-MS/MS, were performed on an in vivo Ang II infusion mice model to obtain a comprehensive view of the protein ensembles associated with thoracic PVAT (tPVAT) dysfunction induced by Ang II. In total, 5037 proteins were confidently identified, of which 4984 proteins were quantified. Compared with the saline group, 145 proteins were upregulated and 146 proteins were downregulated during Ang II-induced tPVAT pathogenesis. Bioinformatics analyses revealed that the most enriched GO terms were annotated as gene silencing, monosaccharide binding, and extracellular matrix. In addition, some novel proteins, potentially associated with Ang II infusion, were identified, such as acyl-CoA carboxylase α, very long-chain acyl-CoA synthetase (ACSVL), uncoupling protein 1 (UCP1), perilipin, RAS protein-specific guanine nucleotide-releasing factor 2 (RasGRF2), and hypoxia inducible factor 1α (HIF-1α). Ang II could directly participate in the regulation of lipid metabolism, transportation, and adipocyte differentiation by affecting UCP1 and perilipin. Importantly, the key KEGG pathways were involved in fatty acid biosynthesis, FABP3-PPARα/γ, RasGRF2-ERK-HIF-1α, RasGRF2-PKC-HIF-1α, and STAT3-HIF-1α axis. The present study provided the most comprehensive proteome profile of mice tPVAT and some novel insights into Ang II-mediated tPVAT dysfunction and will be helpful for understanding the possible relationship between local RAS activation and PVAT dysfunction.

Deciphering the Role of microRNAs in Large-Artery Stiffness Associated With Aging: Focus on miR-181b

Large artery stiffness (LAS) is a major, independent risk factor underlying cardiovascular disease that increases with aging. The emergence of microRNA signaling as a key regulator of vascular structure and function has stimulated interest in assessing its role in the pathophysiology of LAS. Identification of several microRNAs that display age-associated changes in expression in aorta has focused attention on defining their molecular targets and deciphering their role in age-associated arterial stiffening. Inactivation of the microRNA-degrading enzyme, translin/trax, which reverses the age-dependent decline in miR-181b, confers protection from aging-associated arterial stiffening, suggesting that inhibitors targeting this enzyme may have translational potential. As LAS poses a major public health challenge, we anticipate that future studies based on these advances will yield innovative strategies to combat aging-associated arterial stiffening.

Degradation of Premature-miR-181b by the Translin/Trax RNase Increases Vascular Smooth Muscle Cell Stiffness

[Figure: see text].

Elevated body fat increases amphetamine accumulation in brain: evidence from genetic and diet-induced forms of adiposity

Despite the high prevalence of obesity, little is known about its potential impact on the pharmacokinetics of psychotropic drugs. In the course of investigating the role of the microRNA system on neuronal signaling, we found that mice lacking the translin/trax microRNA-degrading enzyme display an exaggerated locomotor response to amphetamine. As these mice display robust adiposity in the context of normal body weight, we checked whether this phenotype might reflect elevated brain levels of amphetamine. To assess this hypothesis, we compared plasma and brain amphetamine levels of wild type and Tsn KO mice. Furthermore, we checked the effect of diet-induced increases in adiposity on plasma and brain amphetamine levels in wild type mice. Brain amphetamine levels were higher in Tsn KO mice than in wild type littermates and correlated with adiposity. Analysis of the effect of diet-induced increases in adiposity in wild type mice on brain amphetamine levels also demonstrated that brain amphetamine levels correlate with adiposity. Increased adiposity displayed by Tsn KO mice or by wild type mice fed a high-fat diet correlates with elevated brain amphetamine levels. As amphetamine and its analogues are widely used to treat attention deficit disorder, which is associated with obesity, further studies are warranted to assess the impact of adiposity on amphetamine levels in these patients.