Novel chimeric peptides based on endomorphins and ghrelin receptor antagonist produced supraspinal antinociceptive effects with reduced acute tolerance in mice.

It is widely recognized that developing bi- or multifunctional opioid compounds could offer a valuable approach to pain management with fewer side effects compared to single-target compounds. In this study, we designed and characterized two novel chimeric peptides, EM-1-DLS and EM-2-DLS, incorporating endomorphins (EMs) and the ghrelin receptor antagonist [D-Lys3]-GHRP-6 (DLS). Functional assays demonstrated that EM-1-DLS and EM-2-DLS acted as κ-opioid receptor (κ-OR)-preferring agonists, weak µ-opioid receptors (µ-OR) and ghrelin receptor (GHSR) agonists. Upon intracerebroventricular (i.c.v.) administration in mice, both EM-1-DLS and EM-2-DLS exhibited dose- and time-dependent antinociceptive effects in the tail withdrawal test. EM-1-DLS demonstrated the highest antinociceptive potency among the peptides, with an ED50 approximately 8-fold greater than EM-1, while EM-2-DLS showed comparable effects to EM-2. The antinociceptive actions of EM-1-DLS involved activation of GHS-R1α, µ-OR, and κ-OR, whereas EM-2-DLS acted via GHS-R1α, δ-OR, and κ-OR pathways. Additionally, acute antinociceptive tolerance was investigated, revealing that EM-1-DLS induced a tolerance ratio of 2.33-fold, significantly lower than the 5.19-fold ratio induced by EM-1. Cross-tolerance ratios between the chimeric peptides and EMs ranged from 0.92 to 1.76, indicating reduced tolerance compared to EMs alone. These findings highlight the potential of these chimeric peptides to mitigate pain with diminished tolerance development, suggesting a promising strategy for the development of new analgesic therapies with improved safety profiles.

L4-to-L4 nerve root transfer for hindlimb hemiplegia after hypertensive intracerebral hemorrhage.

There is no effective treatment for hemiplegia after hypertensive intracerebral hemorrhage. Considering that the branches of L4 nerve roots in the lumbar plexus root control the movement of the lower extremity anterior and posterior muscles, we investigated a potential method of nerve repair using the L4 nerve roots. Rat models of hindlimb hemiplegia after a hypertensive intracerebral hemorrhage were established by injecting autogenous blood into the posterior limb of internal capsule. The L4 nerve root on the healthy side of model rats was transferred and then anastomosed with the L4 nerve root on the affected side to drive the extensor and flexor muscles of the hindlimbs. We investigated whether this method can restore the flexible movement of the hindlimbs of paralyzed rats after hypertensive intracerebral hemorrhage. In a beam-walking test and ladder rung walking task, model rats exhibited an initial high number of slips, but improved in accuracy on the paretic side over time. At 17 weeks after surgery, rats gained approximately 58.2% accuracy from baseline performance and performed ankle motions on the paretic side. At 9 weeks after surgery, a retrograde tracing test showed a large number of fluoro-gold-labeled motoneurons in the left anterior horn of the spinal cord that supports the L4-to-L4 nerve roots. In addition, histological and ultramicrostructural findings showed axon regeneration of motoneurons in the anterior horn of the spinal cord. Electromyography and paw print analysis showed that denervated hindlimb muscles regained reliable innervation and walking coordination improved. These findings suggest that the L4-to-L4 nerve root transfer method for the treatment of hindlimb hemiplegia after hypertensive intracerebral hemorrhage can improve the locomotion of hindlimb major joints, particularly of the distal ankle. Findings from study support that the L4-to-L4 nerve root transfer method can effectively repair the hindlimb hemiplegia after hypertensive intracerebral hemorrhage. All animal experiments were approved by the Animal Ethics Committee of the First Affiliated Hospital of Nanjing Medical University (No. IACUC-1906009) in June 2019.

Loss of MicroRNA-137 Impairs the Homeostasis of Potassium in Neurons via KCC2

Neuropsychiatric disorders are the leading cause of mental and intellectual disabilities worldwide. Current therapies against neuropsychiatric disorders are very limited, and very little is known about the onset and development of these diseases, and their most effective treatments. MIR137 has been previously identified as a risk gene for the etiology of schizophrenia, bipolar disorder, and autism spectrum disorder. Here we generated a forebrain-specific MIR137 knockout mouse model, and provided evidence that loss of miR-137 resulted in impaired homeostasis of potassium in mouse hippocampal neurons. KCC2, a potassium-chloride co-transporter, was a direct downstream target of miR-137. The KCC2 specific antagonist VU0240551 could balance the current of potassium in miR-137 knockout neurons, and knockdown of KCC2 could ameliorate anxiety-like behavior in MIR137 cKO mice. These data suggest that KCC2 antagonists or knockdown might be beneficial to neuropsychiatric disorders due to the deficiency of miR-137.

Effects of neural stem cell transplantation on the motor function of rats with contusion spinal cord injuries: a meta-analysis.

OBJECTIVE: To judge the efficacies of neural stem cell (NSC) transplantation on functional recovery following contusion spinal cord injuries (SCIs). DATA SOURCES: Studies in which NSCs were transplanted into a clinically relevant, standardized rat model of contusion SCI were identified by searching the PubMed, Embase and Cochrane databases, and the extracted data were analyzed by Stata 14.0. DATA SELECTION: Inclusion criteria were that NSCs were used in in vivo animal studies to treat contusion SCIs and that behavioral assessment of locomotor functional recovery was performed using the Basso, Beattie, and Bresnahan lo-comotor rating scale. Exclusion criteria included a follow-up of less than 4 weeks and the lack of control groups. OUTCOME MEASURES: The restoration of motor function was assessed by the Basso, Beattie, and Bresnahan locomotor rating scale. RESULTS: We identified 1756 non-duplicated papers by searching the aforementioned electronic databases, and 30 full-text articles met the inclusion criteria. A total of 37 studies reported in the 30 articles were included in the meta-analysis. The meta-analysis results showed that transplanted NSCs could improve the motor function recovery of rats following contusion SCIs, to a moderate extent (pooled standardized mean difference (SMD) = 0.73; 95% confidence interval (CI): 0.47-1.00; P < 0.001). NSCs obtained from different donor species (rat: SMD = 0.74; 95% CI: 0.36-1.13; human: SMD = 0.78; 95% CI: 0.31-1.25), at different donor ages (fetal: SMD = 0.67; 95% CI: 0.43-0.92; adult: SMD = 0.86; 95% CI: 0.50-1.22) and from different origins (brain-derived: SMD = 0.59; 95% CI: 0.27-0.91; spinal cord-derived: SMD = 0.51; 95% CI: 0.22-0.79) had similar efficacies on improved functional recovery; however, adult induced pluripotent stem cell-derived NSCs showed no significant efficacies. Furthermore, the use of higher doses of transplanted NSCs or the administration of immunosuppressive agents did not promote better locomotor function recovery (SMD = 0.45; 95% CI: 0.21-0.70). However, shorter periods between the contusion induction and the NSC transplantation showed slightly higher efficacies (acute: SMD = 1.22; 95% CI: 0.81-1.63; subacute: SMD = 0.75; 95% CI: 0.42-1.09). For chronic injuries, NSC implantation did not significantly improve functional recovery (SMD = 0.25; 95% CI: -0.16 to 0.65). CONCLUSION: NSC transplantation alone appears to be a positive yet limited method for the treatment of contusion SCIs.

Chemical Constituents from Bletilla Ochracea / 昆明医科大学学报

Objective To study the chemical constituents from Bletilla ochracea. Methods The compounds were extracted by 95％ alcohol and isolated by column chromatography on silica gel and Sephadex LH-20. Their structures were identified by spectroscopic analysis (～1 H NMR and 13 CNMR).Results Nine compouds were obtained and identified as lusianthridin (1), 1, 2, 7-trihydroxy-4-methoxy-9, 10-dihydroxyphenanthrene (2), nudol (3), coelonin (4), batatasin Ⅲ (5), 3, 7-dihydroxy-2, 4-dimethoxyphenanthrene (6), daucosterol (7), β-sitosterol (8), stigmasterol (9).Conclus ion Compounds 2, 3, 5 were isolated from this plant for the first time.

Neurogenin 2 converts mesenchymal stem cells into a neural precursor fate and improves functional recovery after experimental stroke.

BACKGROUND: Neurogenin2 (Ngn2) is a proneural gene that directs neuronal differentiation of progenitor cells during development. Here, we investigated whether Ngn2 can reprogram MSCs to adopt a neural precursor fate and enhance the therapeutic effects of MSCs after experimental stroke. METHODS: In vitro, MSCs were transfected with lenti-GFP or lenti-Ngn2. Following neuronal induction, cells were identified by immunocytochemistry, Western blot and electrophysiological analyses. In a stroke model induced by transient right middle cerebral artery occlusion (MCAO), PBS, GFP-MSCs or Ngn2-MSCs were injected 1 day after MCAO. Behavioral tests, neurological and immunohistochemical assessments were performed. RESULTS: In vitro, Ngn2-MSCs expressed neural stem cells markers (Pax6 and nestin) and lost the potential to differentiate into mesodermal cell types. Following neural induction, Ngn2-MSCs expressed higher levels of neuron-specific proteins MAP2, Tuj1 and NeuN, and also expressed voltage-gated Na+ channel, which was absent in GFP-MSCs. In vivo, after transplantation, Ngn2-MSCs significantly reduced apoptotic cells, decreased infarct volume, and increased the expression of VEGF and BDNF. Finally, Ngn2-MSCs treated animals showed the highest functional recovery among the three groups. CONCLUSIONS: Ngn2 was sufficient to convert MSCs into a neural precursor fate and transplantation of Ngn2-MSCs was advantageous for the treatment of stroke rats.