Alpha 2-adrenoceptor participates in anti-hyperalgesia by regulating metabolic demand.

The α2-adrenoceptor agonist dexmedetomidine is a commonly used drug for sedatives in clinics and has analgesic effects; however, its mechanism of analgesia in the spine remains unclear. In this study, we systematically used behavioural and transcriptomic sequencing, pharmacological intervention, electrophysiological recording and ultrasound imaging to explore the analgesic effects of the α2-adrenoceptor and its molecular mechanism. Firstly, we found that spinal nerve injury changed the spinal transcriptome expression, and the differential genes were mainly related to calcium signalling and tissue metabolic pathways. In addition, α2-adrenoceptor mRNA expression was significantly upregulated, and α2-adrenoceptor was significantly colocalised with markers, particularly neuronal markers. Intrathecal dexmedetomidine suppressed neuropathic pain and acute inflammatory pain in a dose-dependent manner. The transcriptome results demonstrated that the analgesic effect of dexmedetomidine may be related to the modulation of neuronal metabolism. Weighted gene correlation network analysis indicated that turquoise, brown, yellow and grey modules were the most correlated with dexmedetomidine-induced analgesic effects. Bioinformatics also annotated the involvement of metabolic processes and neural plasticity. A cardiovascular-mitochondrial interaction was found, and ultrasound imaging revealed that injection of dexmedetomidine significantly enhanced spinal cord perfusion in rats with neuropathic pain, which might be regulated by pyruvate dehydrogenase kinase 4 (pdk4), cholesterol 25-hydroxylase (ch25 h) and GTP cyclohydrolase 1 (gch1). Increasing the perfusion doses of dexmedetomidine significantly suppressed the frequency and amplitude of spinal nerve ligation-induced miniature excitatory postsynaptic currents. Overall, dexmedetomidine exerts analgesic effects by restoring neuronal metabolic processes through agonism of the α2-adrenoceptor and subsequently inhibiting changes in synaptic plasticity.

Metformin Alleviates Pain States by Regulating the Balance of Spinal Synaptic Transmission.

BACKGROUND: Metformin has been shown to have potent analgesic effects; however, the underlying mechanism of synaptic plasticity mediating analgesia remained ambiguous. METHODS: In this study, animal behavioral tests, whole-cell patch­clamp recording, immunofluorescence staining, and network pharmacology techniques were applied to elucidate the mechanisms and potential targets of metformin-induced analgesia. RESULTS: Single or consecutive injections of metformin significantly inhibited spinal nerve ligation (SNL)-induced neuropathic pain, and formalin-induced acute inflammatory pain. Network pharmacology analysis of metformin action targets in pain database-related targets revealed 25 targets, including five hub targets (nitric oxide synthase 1 (NOS1), NOS2, NOS3, epidermal growth factor receptor (EGFR), and plasminogen (PLG)). Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis demonstrated that metformin-induced analgesia was markedly correlated with calcium signaling and synaptic transmission. Intrathecal injection of metformin significantly reversed nerve injury-induced c-Fos (neural activity biomarker) mRNA and protein expression in neuropathic rats by regulating NOS2 expression. In addition, whole-cell recordings of isolated spinal neurons demonstrated that metformin dose-dependently inhibited the enhanced frequency and amplitude of miniature excitatory synaptic currents (mEPSCs) but did not affect those of miniature inhibitory synaptic currents (mIPSCs) in neuropathic pain. CONCLUSIONS: This study further demonstrated that metformin might inhibit spinal glutamatergic transmission and abnormal nociceptive circuit transduction by monitoring synaptic transmission in pain. Results of this work provide an in-depth understanding of metformin analgesia via synaptic plasticity.

Picroside â ¡ attenuates neuropathic pain by regulating inflammation and spinal excitatory synaptic transmission.

Nerve injury induced microglia activation, which released inflammatory mediators and developed neuropathic pain. Picroside Ⅱ (PⅡ) attenuated neuropathic pain by inhibiting the neuroinflammation of the spinal dorsal horn; however, how it engaged in the cross talk between microglia and neurons remained ambiguous. This study aimed to investigate PⅡ in the modulation of spinal synaptic transmission mechanisms on pain hypersensitivity in neuropathic rats. We investigated the analgesia of PⅡ in mechanical and thermal hyperalgesia using the spinal nerve ligation (SNL)-induced neuropathic pain model and formalin-induced tonic pain model, respectively. RNA sequencing and network pharmacology were employed to screen core targets and signaling pathways. Immunofluorescence staining and qPCR were performed to explore the expression level of microglia and inflammatory mediator mRNA. The whole-cell patch-clamp recordings were utilized to record miniature excitatory postsynaptic currents in excitatory synaptic transmission. Our results demonstrated that the analgesic of PⅡ was significant in both pain models, and the underlying mechanism may involve inflammatory signaling pathways. PⅡ reversed the SNL-induced overexpression of microglia and inflammatory factors. Moreover, PⅡ dose dependently inhibited excessive glutamate transmission. Thus, this study suggested that PⅡ attenuated neuropathic pain by inhibiting excitatory glutamate transmission of spinal synapses, induced by an inflammatory response on microglia.

Study on total residual oxidant decay in long-distance seawater intake pipeline of cooling system.

Electrochlorination is often used for biofouling control along the water intake pipeline of seawater cooling system, but with the increasing of pipeline length, this process needs to be further improved. In this study, the dynamic circulation and field pilot test were used to simulate the long-distance seawater intake pipeline, investigating total residual oxidant (TRO) decay and its influencing factors by comparing the bench test. The results showed that intermediate dosing could increase terminal TRO, but also reduce the CT value, resulting in decline of local inactivation effect. The initial concentration of dynamic cycle test was higher than that of bench test under the same terminal TRO, and the difference value between the two was affected by holding time. When the initial concentration was greater than 8.5 mg L-1, TRO decay rate was proportional to the seawater flow rate and inversely proportional to the initial concentration. The initial concentration of 8.5-10 mg L-1 could meet TRO decay requirement under 3 h holding time, and the dosing concentration could be reduced to 6 mg L-1 when the temperature was low. The results provided important guidance for the actual operation of biofouling control in long-distance water intake pipelines of cooling system.

The movement and settlement behaviour of cyprids of Balanus reticulatus on the surfaces of the titanium alloys.

The motion paths of Balanus reticulatus cyprids were similar on all the titanium alloys surfaces. On the parallel grinding surfaces, the temporary attachment duration and the settlement ratio of the cyprids were influenced by the roughness and the composition of the surfaces and correlated positively. The surface roughness could also change the contact area and the numbers of the attachment points of the cyprids in the similar pattern. Consequently, the roughness and the composition of the surfaces regulated the cyprid settlement by the temporary attachment duration. The cross grinding increased the temporary attachment duration but drastically decreased the settlement ratio to 0 compared to the parallel grinding, possibly due to the voids and the drastic decrease of the contact area and the numbers of the attachment points of the cyprids on the cross grinding surface, respectively. The cross grinding therefore significantly reduced the cyprid settlement compared to the parallel grinding.

Systematic Investigation of mRNA N 6-Methyladenosine Machinery in Primary Prostate Cancer.

BACKGROUND: Appreciable findings have pointed out pivotal roles of N 6-methyladenosine (m6A) machinery in cancer onset and progression. However, limited efforts have been directed towards relevant research in the prostate cancer area. METHODS: A PubMed search was conducted to acquire components of the mRNA m6A machinery. Multiomics integration was performed to systematically investigate the mRNA m6A machinery in primary prostate cancer. Furthermore, RNA interference assays of two prognostic m6A readers EIF3D and HNRNPA2B1 were conducted to explore m6A dependence of their functions in prostate cancer cell proliferation and migration. RESULTS: A total of 41 mRNA m6A regulators have been identified to date. A small degree of copy number aberrations and an extremely low frequency of somatic mutations were observed in the regulators across prostate tumors. Enrichment of CpG sites and extensive changes of DNA methylation in the m6A machinery were also found. Impact of copy number variation on m6A regulator expression was stronger than that of DNA methylation disturbance. Furthermore, our study identified a set of m6A regulators related to clinical features and/or survival which were largely m6A-binding proteins. The translation initiation factor subunit EIF3D and the splicing factor HNRNPA2B1 can be independent prognostic factors which may contribute to retardation and promotion of cancer progression, respectively, through affecting cancer-related processes such as cell cycle. Moreover, in vitro assays demonstrated that m6A impacted the EIF3D and HNRNPA2B1 roles in proliferation and migration of prostate cancer cells. CONCLUSIONS: Our report systematically described molecular features of the mRNA m6A machinery and their potential roles in primary prostate cancer. Knowledge gained from this work may pave the way for further studies on the m6A system in prostate cancer.

Loss of Microglia and Impaired Brain-Neurotrophic Factor Signaling Pathway in a Comorbid Model of Chronic Pain and Depression.

Major depressive disorder (MDD) and chronic pain are two complex disorders that often coexist. The underlying basis for this comorbidity is unknown. In the current investigation, microglia and the brain-derived neurotrophic factor (BDNF)-cAMP response element-binding protein (CREB) pathway were investigated. A comorbidity model, with characteristics of both MDD and chronic pain, was developed by the administration of dextran sodium sulfate (DSS) and the induction of chronic unpredictable psychological stress (CUS). Mechanical threshold sensory testing and the visceromotor response (VMR) were employed to measure mechanical allodynia and visceral hypersensitivity, respectively. RT-qPCR and western blotting were used to assess mRNA and protein levels of ionized calcium-binding adaptor molecule 1 (Iba-1), nuclear factor-kappa B (NF-κB), nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκBa), BDNF, and CREB. In comorbid animals, mechanical allodynia and visceral hypersensitivities were significant with increased mRNA and protein levels for NF-κB-p65 and IκBa. Furthermore, the comorbid animals had deceased mRNA and protein levels for Iba-1, BDNF, and CREB as well as a reduced number and density of microglia in the medial prefrontal cortex (mPFC). These results together suggest that DSS and CUS can induce the comorbidities of chronic pain and depression-like behavior. The pathology of this comorbidity involves loss of microglia within the mPFC with subsequent activation of NF-κB-p65 and down-regulation of BDNF/p-CREB signaling.

Postnatal Vitamin D Intake Modulates Hippocampal Learning and Memory in Adult Mice.

Vitamin D (VD) is a neuroactive steroid crucial for brain development, function and homeostasis. Its deficiency is associated with numerous brain conditions. As such, VD and its variants are routinely taken by a broad of groups with/without known VD deficiency. In contrast, the harmful effects of VD overdose have been poorly studied. Similarly, the developmental stage-specific VD deficiency and overdose have been rarely explored. In the present work, we showed that postnatal VD supplementation enhanced the motor function transiently in the young adult, but not in the older one. Postnatal VD intake abnormality did not impact the anxiety and depressive behavior but was detrimental to spatial learning and hippocampus-dependent memory. At the molecular level we failed to observe an obvious and constant change with the neural development and activity-related genes examined. However, disrupted developmental expression dynamics were observed for most of the genes, suggesting that the altered neural development dynamics and therefore aberrant adult plasticity might underlie the functional deficits. Our work highlights the essence of VD homeostasis in neural development and adult brain function. Further studies are needed to determine the short- and long-term effects VD intake status may have on brain development, homeostasis, and diseases.

High expression of TIG3 predicts poor survival in patients with primary glioblastoma.

TIG3 (tazarotene-induced gene 3) has been reported to suppress the progression of several malignancies, where this gene is universally downregulated. However, the expression of TIG3 in primary glioblastoma and its relevance to patient's prognosis have not been elaborated. Thus, this study was aimed to evaluate TIG3 expression level in primary glioblastoma and investigate the prognostic value of TIG3 for patients. The Cancer Genome Atlas database was first utilized to analyze the expression and prognostic potential of TIG3 in 528 glioblastoma cases. Compared with control group, glioblastoma showed significantly elevated TIG3 expression (p < 0.001). Log-rank analysis revealed that higher expression of TIG3 was associated with shorter overall survival (358vs 383 days, p = 0.039). Furthermore, TIG3 protein expression detected by immunohistochemistry confirmed positive correlation of TIG3 expression and glioma grade and upregulation of TIG3 in our cohort of 101 primary glioblastoma patients compared to 16 normal brains. Finally, Kaplan-Meier analysis and Cox regression analysis identified high TIG3 expression as an independent risk factor for overall survival of primary glioblastoma patients (overall survival, 10 vs 13 months, p = 0.033; hazard ratio = 1.542, p = 0.046). Together, this study indicated that increased expression of TIG3 in primary glioblastoma is a novel biomarker for predicting poor outcome of patients. We then hypothesize that TIG3 may function in a different pattern in glioblastoma.