µ-opioid receptor, β-endorphin, and cannabinoid receptor-2 are increased in the colonic mucosa of irritable bowel syndrome patients

BACKGROUND AND AIMS

The gut immune, cannabinoid, and opioid systems constitute an integrated network contributing to visceral sensation and pain modulation. We aimed to assess the expression of the µ-opioid receptor (MOR), its ligand β-endorphin (β-END), and cannabinoid receptor-2 (CB2 ) in patients with irritable bowel syndrome (IBS) and asymptomatic controls (AC) and their correlation with sex and symptom perception.

METHODS

Mucosal biopsies were obtained from the left colon of 31 IBS patients (45% women) with predominant constipation (IBS-C, 9) or diarrhea (IBS-D, 10) or with mixed bowel habits (IBS-M, 12) and 32 AC (44% women) and processed for qRT-PCR, Western blotting, and immunohistochemistry.

KEY RESULTS

µ-opioid receptor and CB2 mRNA and protein expression and β-END protein levels were increased in patients with IBS compared to AC (all Ps=0.021). A significant sex by IBS interaction was found in relation to CB2 mRNA expression (P = .003) with women showing a markedly higher expression to men (P = .035). In contrast, in AC, men had higher expression than women (P = .033). β-END, MOR, and CB2 immunoreactivities (IR) were localized to CD4+T cells including EMR-1+ eosinophils and CD31+ T cells but not to mast cells.

CONCLUSIONS

The increased expression of MOR, β-END, and CB2 in the mucosa of IBS patients, where they are localized to immune cells, suggests that opioid and cannabinoid systems play an immune-related compensatory role in visceral pain in IBS patients. Further work is necessary to support this hypothesis.

[Clinical characteristics of non-invasive ventilation treatment in children with spinal muscular atrophy and sleep disordered breathing]

Objective: To study the short-term and long-term efficacy of the non-invasive ventilation treatment in children with spinal muscular atrophy (SMA) and sleep-disordered breathing. Methods: This was a prospective research to study the effect of night-time non-invasive ventilation in children with SMA and moderate to severe sleep-disordered breathing during March 2016 to January 2018, from the Pulmonary Department of Capital Institute of Pediatrics Affiliated Children's Hospital. Patients were divided into the treated group (with night-time non-invasive ventilation) and the control group (without ventilator). Sleep breathing pressure titration was suggested to the patients who were prepared to receive non-invasive ventilation. All cases were followed up for one year. Parameters'changes in polysomnography were assessed (paired t-test) in titration patients. Frequency of respiratory tract infection during the next year in the patients with and without ventilation was collected and compared (Mann-Whitney U-test). Results: Seventeen cases were recruited. The average age was (5.1±2.9) years, 10 cases were boys and 7 cases were girls. In the titration group (8 patients), after non-invasive ventilation, the average apnea hypopnea index was (3.8±2.5) times/h (t=4.086, P=0.005), hypopnea index was (2.4±1.2) times/h (t=2.779, P=0.027), average oxygen saturation during total sleep time was 0.966±0.007 (t=-5.292, P=0.001), and the minimum oxygen saturation was 0.906±0.023 (t=-3.938, P=0.006). All the above parameters were significantly improved after treatment. Than before, which was (16.6±9.7) times/h, (7.2±4.7) times/h, 0.946±0.015, 0.786±0.092 respectively. Ventilator mode for the 9 children with long time non-invasive ventilation at home was Bi-level positive airway pressure S/T. The positive airway pressure was set at 8-14 cmH(2)O (1 cmH(2)O=0.098 kPa) in inspiratory phase and 4-6 cmH(2)O in expiratory phase. In the treated group (9 patients), the average frequency of upper respiratory tract infection was 1.0 (0, 3.0) times/year (Z=-2.245, P=0.023), the lower respiratory tract infection was 0 (0, 0) times/year (Z=-3.189, P=0.001), hospitalization was 0 (0, 0) times/year (Z=-3.420, P<0.01), and admission to intensive care unit was 0 (0, 0) times/year (Z=-3.353, P=0.029). All the above indexes were significantly decreased compared with the control group (8 patients), which was 3.0 (2.3, 7.0) times/year, 2.0 (1.3, 4.5) times/year, 1.0 (1.0, 4.3) times/year, 0.5 (0, 1.0) times/year respectively. Conclusion: Non-invasive ventilation is efficient to SMA children with sleep-disordered breathing, and also can reduce the incidence of respiratory tract infections for children with SMA.

History of early life adversity is associated with increased food addiction and sex-specific alterations in reward network connectivity in obesity

BACKGROUND

Neuroimaging studies have identified obesity-related differences in the brain's resting state activity. An imbalance between homeostatic and reward aspects of ingestive behaviour may contribute to obesity and food addiction. The interactions between early life adversity (ELA), the reward network and food addiction were investigated to identify obesity and sex-related differences, which may drive obesity and food addiction.

METHODS

Functional resting state magnetic resonance imaging was acquired in 186 participants (high body mass index [BMI]: ≥25: 53 women and 54 men; normal BMI: 18.50-24.99: 49 women and 30 men). Participants completed questionnaires to assess ELA (Early Traumatic Inventory) and food addiction (Yale Food Addiction Scale). A tripartite network analysis based on graph theory was used to investigate the interaction between ELA, brain connectivity and food addiction. Interactions were determined by computing Spearman rank correlations, thresholded at q < 0.05 corrected for multiple comparisons.

RESULTS

Participants with high BMI demonstrate an association between ELA and food addiction, with reward regions playing a role in this interaction. Among women with high BMI, increased ELA was associated with increased centrality of reward and emotion regulation regions. Men with high BMI showed associations between ELA and food addiction with somatosensory regions playing a role in this interaction.

CONCLUSIONS

The findings suggest that ELA may alter brain networks, leading to increased vulnerability for food addiction and obesity later in life. These alterations are sex specific and involve brain regions influenced by dopaminergic or serotonergic signalling.

Transcriptome-wide analysis of N6-methyladenosine uncovers its regulatory role in gene expression in the lepidopteran Bombyx mori

N6-methyladenosine (m6A) methylation is the most common form of RNA modification in eukaryotes and has been shown to act as an important epitranscriptomic marker, which can regulate gene expression, messenger RNA stability, alternative splicing and translation efficiency. Recent progress on determining insect m6A function has been limited to the dipteran Drosophila melanogaster, in which m6A is involved in neuronal functions and sex determination. Methylation and function of m6A in other insects, however, remain unknown. Here, we investigated a transcriptome-wide profile of m6A in the lepidopteran Bombyx mori and identified the methyltransferase subunits B. mori methyltransferase-like 3 (BmMETTL3) and BmMETTL14 in the m6A methylation pathway. Strikingly, loss of BmMETTL3 and BmMETTL14 in cultured B. mori cells led to arrest of cell cycle progression and caused deficiency of chromosome alignment and segregation. Specifically, we identified 2853 m6A peaks representing transcripts of 2043 genes, and the target genes with m6A methylation were shown to be involved in gene expression and translation. It was interesting that we found that the highly expressed genes tended to be methylated by m6A, and comparative analysis of RNA m6A and DNA N6-methyladenine (6mA) revealed two distinct regulatory mechanisms for gene expression. Overall, our work suggests RNA m6A and DNA 6mA play important roles in RNA and DNA epigenetic regulation in B. mori.

miR-375 inhibits the proliferation and invasion of glioblastoma by regulating Wnt5a

The aberrant expression of microRNA-375 (miR-375) has been proved to be associated with carcinogenesis. However, the role of miR-375 in glioblastoma (GBM) remains unknown. The aim of this study was to investigate biological functions and its molecular mechanisms of miR-375 in GBM cells. In this study, real-time PCR results showed that the level of miR-375 expression in GBM tissues and GBM cell lines (U87 and U251) was decreased. Using MTT assay, Transwell migration and invasion assay, we demonstrated that miR-375 overexpression significantly suppress cell proliferation, cell migration and cell invasion capacity in U87 and U251 cells. However, downregulation of miR-375 had reverse effects on cell proliferation, migration and invasion. Targeting association analysis, dual luciferase assay, RT-PCR and western blot analysis results confirmed that miR-375 could target the 3'UTR of Wnt5a mRNA and regulated its protein expression. Further studies also find overexpression of Wnt5a could significantly reverse miR-375-mediated proliferation, migration and invasion on U87 and U251 cells. Therefore, we concluded that miR-375 inhibited the proliferation and invasion of GBM by regulating Wnt5a and might be a possible therapeutic agent for GBM.

Role of spinal cyclooxygenase-2 and prostaglandin E2 in fentanyl-induced hyperalgesia in rats

BACKGROUND

Accumulated evidence suggests that spinal cyclooxygenase-2 (COX-2) and prostaglandin E2 (PGE2) may be implicated in the development of opioid-induced hyperalgesia.

METHODS

Rats received subcutaneous fentanyl injections at different doses (20-80 μg kg^-1), four separate times at 15-min intervals. Some rats only received fentanyl (60 μg kg^-1 × 4 doses) with or without surgical incision. Fentanyl-induced hyperalgesia was evaluated via a tail-pressure or paw-withdrawal test. The concentrations of spinal COX-2, EP-1 receptor (EP-1R) mRNA, and PGE2 were measured. The effects of the COX-2 inhibitor, parecoxib (intraperitoneal 10 mg kg^-1), or the EP-1R antagonist, SC51089 (intraperitoneal 100 μg kg^-1), on hyperalgesia and spinal PGE2 were examined.

RESULTS

Acute repeated injections of fentanyl dose-dependently induced mechanical hyperalgesia, which reached a peak at the 1^st day and persisted for 1-4 days postinjection. This hyperalgesia could be partly or totally prevented by the pretreatment of either parecoxib or SC51089. Consistently, the levels of spinal COX-2 mRNA and PGE2 were also dose-dependently increased, reaching a peak at the first day and persisting for 2 days postinjection. Pretreatment with parecoxib could block the increase in spinal PGE2 and had no effects on spinal COX-2 and EP-1R mRNA. Fentanyl injection enhanced incision-induced mechanical and thermal hyperalgesia.

CONCLUSIONS

Acute repeated fentanyl administration dose-dependently produced mechanical hyperalgesia and augmented surgery induced postoperative hyperalgesia. This behavioural change was paralleled with an increase in spinal COX-2 mRNA and PGE2 after fentanyl administration. Inhibition of COX-2 or blockade of EP-1R can partly or totally prevent hyperalgesia.

[Effects of tetrandrine on proliferation and activation of cardiac fibroblasts]

OBJECTIVE

To investigate the effects of tetrandrine (Tet) on proliferation and activation of rat cardiac fibroblasts.

METHODS

Firstly, the cell counting kit-8 (cck-8) assay was applied to detect the effects of Tet with different concentrations on proliferation of cardiac fibroblasts. Secondly, transforming growth factor (TGF-β)with a concentration of 5 μg/L was used to induce the cardiac fibroblast activation, and Western blot was performed to measure the expression variation of β-catenin, vimentin (Vm), fibronectin (Fn) and smooth muscle α-actin (SMA). At last, the real-time PCR was conducted to measure the expression change of collagen-1(Col-1) and collagen-3(Col-3).

RESULTS

The cck-8 assay showed that the Tet with different concentrations respectively, which were 0.5 μmol/L, 1 μmol/L, 2 μmol/L, 4 μmol/L, and 8 μmol/L, significantly inhibited the proliferation of cardiac fibroblasts. The viability was decreased to 94.4%,84.9%,74.9%,63.8%and 50.3% respectively of the control group when the Tet concentration changed, and the difference was statistically significant, P=0.043, P<0.001, P<0.001, P<0.001, P<0.001 respectively. Western blot revealed that the expressions of β-catenin, Fn, SMA and Vm, were up-regulated by TGF-β(5 μg/L), the result showed that the difference was statistically significant, and the P values were 0.001,0.008,0.010,0.001 respectively. Then, the up-regulation of β-catenin, Fn and SMA was attenuated by pre-treatment of Tet, and the result also displayed that the difference was statistically significant, and the P values were 0.009, 0.005, 0.019,respectively. While there was no significant change in the expression of Vm, according to Western blotting, and P>0.05,at the same time, real-time PCR indicated that the up-regulations of Col-1 and Col-3 which were induced by TGF-β were blocked by pre-treatment of Tet, the result showed that the difference was statistically significant, P<0.001.

CONCLUSION

According to the experimental results, we can draw the conclusion that: the Tet can significantly inhibit the proliferation of cardiac fibroblasts, meanwhile, it can block the activation of cardiac fibroblasts, which is induced by TGF-β. It is supposed that the Tet may probably have anti myocardial fibrosis, which indicates that it may probably be a medicine which is used to block the cardiac remodeling.