G protein-coupled receptor 30 (GPR30) signaling plays an important role in many regulatory pathways, such as gene expression, cell proliferation and migration. However, whether GPR30 is involved in transcription of the pro-opiomelanocortin (Pomc) gene in pituitary corticotroph cells is currently unknown. Here, we report that GPR30 signaling, activated by the GPR30 specific agonist G-1, increases Pomc expression in the mouse corticotroph cell line AtT-20. G-1 also increased nuclear receptor subfamily 4 group A member 1- and 2-dependent transcription activity and phosphorylation of cyclic adenosine monophosphate response element binding protein. Furthermore, protein kinase A inhibitors strongly attenuated G-1-mediated transactivation. The findings suggest that G-1 stimulates GPR30-mediated mechanisms via cyclic adenosine monophosphate/protein kinase A/nuclear receptor subfamily 4 group A members activity in the regulation of Pomc in corticotroph cells.
Genetic defects in ribosome biogenesis result in a group of diseases called ribosomopathies. Patients with ribosomopathies manifest multiorgan phenotypes, including neurological impairments. A well-characterized ribosomopathy, Shwachman-Diamond syndrome (SDS), is mainly associated with loss-of-function mutations in the causal gene SBDS. Children with SDS have neurodevelopmental disorders; however, the neurological consequences of SBDS dysfunction remain poorly defined. In the present study, we investigated the phenotype of Drosophila melanogaster following knockdown of CG8549, the Drosophila ortholog of human SBDS, to provide evidence for the neurological consequences of reduction in physiological SBDS functions. The pan-neuronspecific knockdown of CG8549 was associated with locomotive disabilities, mechanically induced seizures, hyperactivity, learning impairments, and anatomical defects in presynaptic terminals. These results provide the first evidence of a direct link between a reduction in physiological SBDS function and neurological impairments.
Olfaction starts from olfactory receptor neurons (ORNs) that express olfactory marker protein (OMP). OMP deficit results in various behavioural phenotypes indicating olfactory dysfunction due to the impaired responses of ORNs. Recently, OMP was demonstrated to maintain strong olfaction by buffering olfactory cAMP signalling. However, the impact of OMP on olfaction behaviours, the assessment of which requires time to evaluate odour values, remains largely unexplained. Here, we examined the behaviour of heterozygous OMP+/GFP (HET) mice vs. homologous GFP-knock-in OMPdeficient OMP (GFP/ GFP) (KI) mice during the olfactory investigation of odours with different values. When a swab containing an organic odour was presented, both HET and KI mice swiftly approached and investigated the swab with gradual habituation over test sessions. However, when another similar odour was presented, KI mice investigated the new swab much less intensively than HET mice. Next, mice were placed in a chamber with an aversive odour source in one corner of a test chamber. KI mice more frequently approached the compartment containing the aversive odour source than HET mice. Finally, we trained mice to associate two odours with solutions by utilizing reward-penalty values. HET mice stayed close to the reward-associated odour, while KI mice initially approached the reward-associated odour, occasionally turned towards the penalty-associated odour source and eventually stayed in the reward-odour compartment. Histologically, c-Fos-expressing juxtaglomerular cells were fewer and more broadly distributed around glomeruli in KI mice than HET mice. In conclusion, OMP contributes to the evaluation of odour values by glomerular processing during an olfactory investigation task.
Zika virus (ZIKV) is a mosquito-borne Flavivirus structurally and antigenically related to Dengue virus (DENV). Zika virus has been associated with congenital anomalies and most ZIKV outbreaks have occurred in endemic areas of DENV. The present study investigated the effects of prior DENV serotype 1 (DENV1) immunity in immunocompetent female Swiss mice on gestational ZIKV infection in offspring. Physical/reflex development, locomotor activity, anxiety, visual acuity, and brain-derived neurotrophic factor (BDNF) levels were evaluated in offspring during infancy and adolescence. Anti-DENV1 and anti-ZIKV antibodies were detected in sera of the progenitors, whereas no ZIKV genomes were detected in the offspring brain. Pups from dams with only DENV1 immunity presented alterations of physical/reflex development. Pups from all infected dams exhibited time related impairments in locomotor activity and anxiolytic-like behavior. Offspring from DENV/ZIKV-infected dams exhibited impairments in visual acuity during infancy but not during adolescence, which was consistent with morphometric analysis of the optic nerve. Pups from DENV1-, ZIKV-, and DENV/ZIKV-infected dams exhibited a decrease in BDNF levels during infancy and an increase during adolescence in distinct brain regions. In summary, we found no influence of prior DENV1 immunity on gestational ZIKV infection in offspring, with the exception of alterations of early visual parameters, and an increase in BDNF levels in the hippocampus during adolescence.
Objective: To verify the effect of metformin on spinal cord injury (SCI) through Wnt/beta-catenin signaling pathway. Background: SCI is a serious traumatic disease of the central nervous system. Wnt/beta-catenin signaling pathway plays important roles in SCI. Metformin has been reported to exert neuroprotective effects in the central nervous system. Whether metformin could improve SCI through Wnt/beta-catenin signaling pathway remains unclear. Methods: Rats were divided into sham group, SCI group, SCI + metformin group, metformin + XAV939 group (XAV939 is an effective inhibitor of the Wnt/beta-catenin signaling pathway), and methylprednisolone group. BBB scores were used to detect motor function recovery at different time points (0, 1, 3, 7, 14, 21, and 28 days) in SCI rats. Western blot analysis, immunofluorescence, TUNEL, HE and Nissl staining were used to observe the morphological characteristics of spinal cord tissue and the expression of inflammation and apoptosis in spinal cord neurons. Results: Metformin(50 mg/kg) promoted motor functional recovery in rats after SCI, increased the expressions of beta-catenin and brain derived neurotrophic factor (BDNF), inhibited neuron apoptosis and inflammatory response, and improved the recovery of pathological morphology at the injury site by activating the Wnt/beta-catenin signaling pathway. Conclusion: We found a possible mechanism that metformin could reduce inflammation and apoptosis, and promote functional recovery of SCI rats through activating Wnt/beta-catenin signaling pathway.
Background: Bone fracture may subsequently cause chronic postoperative pain after orthopedic surgery, but mechanisms remain elusive. The necessity of caspase-3 in neuroinflammation and synaptic plasticity has been summarized in pathological pain. Leucine-rich repeat transmembrane protein 1 (LRRTM1) mediates synaptic delivery of AMPA receptor and synaptogenesis. This study evaluated whether caspase-3 and LRRTM1 are required for fracture-associated postoperative allodynia. Methods: A model of tibial fracture with intramedullary pinning in mice was established for the induction of postoperative pain, verified by measurement of mechanical paw withdrawal threshold and cold scores response to acetone. The caspase-3 specific inhibitor, recombinant caspase-3 and LRRTM1 knockdown by shRNA were utilized for the investigation of pathogenesis as well as the prevention of allodynia. Also, the activity of caspase-3 and the expression of LRRTM1 in the spinal dorsal horn were examined by Western blot and RT-qPCR. Results: This study reported that tibial fracture and orthopedic surgery produced long-lasting mechanical allodynia and cold allodynia, along with the up-modulation of spinal caspase-3 activity (but not caspase-3 expression) and LRRTM1 expression. Spinal caspase-3 inhibition prevented fracture-associated behavioral allodynia in a dose-dependent manner. Caspase-3 inhibitor also reduced the spinal increased LRRTM1 level after tibial fracture with pinning. Spinal LRRTM1 deficiency impaired fracture-caused postoperative pain. Intrathecal recombinant caspase-3 facilitated acute pain hypersensitivity and spinal LRRTM1 expression in naive mice, reversing by LRRTM1 knockdown. Conclusion: Our current results demonstrate the spinal up-regulation of LRRTM1 by caspase-3 activation in the development of tibial fracture-associated postoperative pain in mice.
Vascular cognitive impairment (VCI) is the second most common cause of dementia after Alzheimer's disease, and the cognitive impairment is one of the common effects of VCI. Unfortunately, it lacks effective therapeutic treatments at present. In our previous study, environmental enrichment (EE), as an early intervention for lifestyle modification, can ameliorate cognitive impairment by attenuating hippocampal blood-brain barrier (BBB) injury in chronic cerebral hypoperfusion (CCH) rats. However, the underlying mechanism remains unclear. Here, we found CCH rats in the standard environment (SE) developed cognitive impairment and BBB damage, which were significantly alleviated with the EE intervention. Meantime, EE improved the autophagy dysfunction caused by CCH in the hippocampus of rats, suggesting that the effect of EE on cognitive function and BBB may be related to the improvement of autophagy pathway.
Purpose: This study seeks to evaluate effects of expectations and conditioning on dry breath holding. Methods: Sixty healthy volunteers were subdivided into 3 groups and were tested across 4 breath holding trials. Participants of the Control group (C) did not undergo any manipulation. Participants of the placebo (P) and nocebo (N) groups were told that they would inhale O2 (actually sham O2) or CO2 (actually sham CO2) along with opposite information that this would enhance or worsen their breath holding time, respectively. Opposite conditioning paradigms based on false visual feedback were employed to reinforce participants' positive (placebo) and negative (nocebo) beliefs. Results: The P group showed the greater increase in breath holding time from baseline to the last trial (p = 0.0001) and the longest breath holding time in the last trial compared to the C group (p = 0.02) and the N group (p = 0.0001). Additionally, in the last trial the P group showed a greater decrease in peripheral oxygen saturation (SpO2) as compared to the C group (p = 0.04) and the N group (p = 0.001). Heart rate (HR) was accelerated in the N group during breath holding (in comparison to the P group [p = 0.04] and C group [p = 0.04]). Conclusions: Psychological components can affect behavioral and physiological parameters in breath holding. This study may inform future research about the role of placebo and nocebo effects for conditions in which critical functions are at play.
It has been reported that the Gonadotropin-releasing hormone (GnRH) and its agonist leuprolide acetate (LA) can act as promoters of nerve regeneration. The aim of this study is to evaluate the effect of LA in a complete transection model. Sciatic nerve injury (SNI) was performed using a complete nerve transection and immediately repaired by epineural sutures. Rats were divided into three groups: SHAM, SNI treated with LA (SNI + LA) or saline solution (SNI + SS) for 5 weeks. Sciatic nerve regeneration was evaluated by kinematic gait analyzes, electrophysiological, morphological and biochemical tests. SNI + LA group had a functional recovery in kinematic gait, an increase in ankle angle value and a faster walking speed, compound muscle action potential amplitude, nerve conduction velocity (NCV). Furthermore, the number of myelinated axons and microtubuleassociated protein 2 (MAP-2) expression were also higher compared to SS group. In conclusion, LA treatment improves of gait, walking speed, NCV, axons morphometry and MAP-2 expression in rats with sciatic nerve complete transection. These results suggest that LA can be a potential treatment for peripheral nerve injuries.
Dry needling treatment has a promising relieving effect on Myofascial Pain Syndrome (MPS). In China, acupuncture practitioners use acupuncture needle instead to insert the "A-Shi" acupoint to treat MPS which is defined as the same as the trigger point of dry needling. This method has been applied for thousands of years in China. In this study, bupivacaine injection induced gastrocnemius muscle injury in mice. We applied the clinical improved needling method on animal model by making the angle between the skin and needle less than 30 degree. Animals got needling treatment 24 h later at the point where the bupivacaine was injected. Results of muscle H.E. staining showed that, compared to bupivacaine injection group without needling, acupuncture treatment group showed more intact muscle fibers, less inflammatory cell infiltration and fractured muscle fibers. By RNA sequencing analysis, our work firstly demonstrated that the physical stimulation of needling changed the gene expression of muscle tissue to accelerate the muscular regeneration process. Therefore, our study proved that simple needling at "A-Shi" acupoint promoted muscle regeneration and revealed underlying mechanisms of the beneficial effects of acupuncture and dry needle treatments.
Serotonin (5-HT) and its innervation have been implicated in various neural functions including circadian systems. Although classical studies have examined the 5-HT innervation pattern in the adult suprachiasmatic nucleus (SCN), the fine-grained morphological study of the development of pathway and terminal projections to the SCN remains scarce. Here, we utilize transgenic mice expressing GFP under the serotonin transporter (SERT) promoter to subserve our developmental mapping study. We demonstrate that the morphology of 5-HT pathway fibers decussating over the supraoptic commissure that projects to the SCN exhibits two distinct developmental patterns. The punctate fibers at the fetal stage gradually become smooth and filamentous, especially during postnatal one week and remain constant thereafter. The innervation field in the SCN develops properly only during postnatal two weeks. Its ventromedial area remains one of the highest 5-HT innervated areas in the adult brain, whereas the dorsolateral area is less innervated. Thus, we provide novel and specific insights on the developmental map of 5-HT system into the SCN using transgenic mouse.
Aim: The purposes of this study were to explore the optimal time for starting walking training in the first month after spinal cord injury (SCI) in rats and to discuss the relationship between changes in motor function and transcranial electrical motor evoked potentials (tceMEPs). Methods: Four groups of rats with SCI (BSWTT-3, 7, 14, 12) performed body-weight-supported treadmill training (BWSTT) for three weeks beginning at 3, 7, 14, and 21 days after SCI, respectively. The Basso, Beattie, and Bresnahan (BBB) score and tceMEPs were assessed weekly. Weekly repeated measures and multiple comparisons between groups were performed to identify differences in motor function and tceMEPs. Correlation analysis was performed to clarify the relationship between BBB scores and tceMEPs over time. Results: Although there was no significant difference between the BWSTT-14 group and the other three BWSTT groups at the end of the experiment in terms of BBB scores and the latency of tceMEPs, the BWSTT-14 group obtained the best trends in improvement of BBB scores and the latencies and amplitudes of tceMEPs over time. The BBB scores of rats with SCI were strongly negatively correlated with tceMEPs latency. The BBB scores of rats with SCI, except for the rats in the BWSTT-3 group, were strongly positively correlated with the tceMEPs amplitude. Conclusions: The preliminary conclusion was that based on a rat model, 14 days after SCI was the optimal time for starting BWSTT. tceMEPs were an objective indicator of spinal cord nerve function, which was strongly correlated with motor function recovery. However, one limitation of this study was that the rats in the Sham group did not undergo BWSTT, which made the training itself a confounding factor for the results.
Background: Spinal cord injury (SCI) is a serious central nervous system condition with no effective clinal treatment. Recently, transplantation of bone marrow mesenchymal stem cells (MSCs) derived exosomes has been proposed as a potential treatment for SCI. However, whether exosomes have similar functions as transplanted human placenta-derived MSCs(hPMSCs) has remained unclear. Methods: The hPMSCs-derived exosomes (hPMSCs-Exos) were extracted using a sequential centrifugation approach. Then, the effects of hPMSCs-Exos on angiogenesis were analysis both in vitro and in vivo. In addition, the sensory and locomotor functions of mice after SCI were also analyzed. Results: The administration of hPMSCs-Exos promote the tube formation and migration of human umbilical vein endothelial cell (HUVECs). Furthermore, vessel numbers, vessel volume fraction and vessel connectivity in spinal cords significantly increased after exosomes were intrathecally injected in the SCI model. In addition, the locomotor and sensory function, also significantly improved in the exosome treatment group. Conclusions: The results of the present study demonstrated that hPMSCs-Exos have proangiogenic effects on endothelial cells and enhanced angiogenesis in SCI model. Thus, this treatment strategy demonstrates great potential for the treatment of SCI.
The aim of the current study was to determine effects of intracerebroventricular (ICV) and intraperitoneal (i.p.) administration of Methylamine (MET) and possible interactions with nitric oxide (NO) and TAAR(1) pathways in 24-h fasted (FD24) and ad libitum layer-type chicken. In experiment 1, FD24 chicken ICV injected with MET (15, 30, 45, 60 and 75 mu g). In experiment 2, ICV injection of MET (15, 30, 45, 60 and 75 mu g) was injected in the ad libitum birds. Experiments 3-4 were similar to experiments 1-2, except chicken i.p. injected with MET (15, 30, 45, 60 and 75 mg/kg). In experiment 5, FD24 birds ICV injected with L-NAME (NO synthesis inhibitor, 100 nmol), MET (75 mu g) and co-injection of L-NAME + MET. Experiment 6 was similar to experiment 5, except, ad libitum birds received injections. In experiment 7, FD24 chicken i.p. injected with L-NAME (100 mg/kg), MET (75 mg/kg) and co-injection of L-NAME + MET. In experiment 8, FD24 birds ICV injected with RO5256390 (selective TAAR(1) agonist, 10, 20 and 40 mu g). In experiment 9, ad libitum birds ICV injected with RO5256390 (10, 20 and 40 mu g). In experiment 10, FD24 birds ICV injected with RO5256390 (10 mu g), MET (75 mu g) and their co-injection. Experiment 11 was similar to experiment 10, except, ad libitum birds received ICV injections. In experiment 12, FD24 chicken i.p. injected with RO5256390 (2.5, 5 and 10 mg/kg). In experiment 13, FD24 chicken i.p. injected with RO5256390 (2.5 mg/kg), MET (75 mg/kg) and RO5256390 + MET. Then cumulative food intake was determined until 120 min after injection. According to the results, ICV injection of MET decreased food intake in FD24 and ad libitum chicken (P < 0.05). MET (i.p.) diminished food consumption in fasted (P < 0.05) but not in ad libitum chicken (P > 0.05). Co-injection of the L-NAME + MET significantly decreased MET-induced hypophagia in FD24 and ad libitum chicken (P < 0.05). MET-induced hypophagia (i.p.) weakened by L-NAME in FD24 chicken (P < 0.05). RO5256390 decreased food intake in FD24 and ad libitum chicken (P < 0.05). Co-injection of RO5256390 + MET increased MET-induced hypophagia in FD24 and ad libitum chicken (P < 0.05). RO5256390 decreased food intake in FD24 chicken (P < 0.05). Co-injection of the RO5256390 + MET amplified MET-induced hypophagia in FD24 chicken (P < 0.05). Based on the findings, MET-induced hypophagia is mediated via NO and TAAR(1) pathways on food intake in layer chicken.
Synaptotagmin-11 (Syt11) is associated with schizophrenia and Parkinson's disease (PD) and is a critical substrate of parkin, an E3 ubiquitin ligase linked to PD. Previously we reported that Syt11 regulates multiple membrane trafficking pathways in neurons and glia. However, the regulation of Syt11 degradation remains largely unknown. As the ubiquitin-proteasome pathway (UPP) plays crucial roles in protein degradation and quality control, we investigated UPP-dependent Syt11 degradation in this study. We found that Syt11 is a shortlived protein with a half-life of 1.49 h in the presence of a protein synthesis inhibitor cycloheximide and is mainly degraded by UPP in neurons. The degradation was further accelerated under sustained neuronal activity and was parkin-dependent. Interestingly, Syt11 had a faster turnover in astrocytes with a half-life of 0.58 h, and UPP partially contributed to its degradation. Mechanical stress applied on astrocytes by hypoosmotic treatment led to reduced Syt11 protein level but increased parkin level. However, the degradation of Syt11 was parkin independent under both isoosmotic and hypoosmotic condition. Altogether, our results revealed active and distinct proteolytic regulation of Syt11 in neurons and astrocytes.