RESUMEN
The P/Q-type voltage-dependent calcium channel (Cav2.1) in the presynaptic membranes of motor nerve terminals plays an important role in regulating Ca2+ transport, resulting in transmitter release within the nervous system. The recovery of Ca2+-dependent signal transduction on motor end plates (MEPs) and innervated muscle may directly reflect nerve regeneration following peripheral nerve injury. Although the functional significance of calcium channels and the levels of Ca2+ signalling in nerve regeneration are well documented, little is known about calcium channel expression and its relation with the dynamic Ca2+ ion distribution at regenerating MEPs. In the present study, end-to-side neurorrhaphy (ESN) was performed as an in vivo model of peripheral nerve injury. The distribution of Ca2+ at regenerating MEPs following ESN was first detected by time-of-flight secondary ion mass spectrometry, and the specific localization and expression of Cav2.1 channels were examined by confocal microscopy and western blotting. Compared with other fundamental ions, such as Na+ and K+, dramatic changes in the Ca2+ distribution were detected along with the progression of MEP regeneration. The re-establishment of Ca2+ distribution and intensity were correlated with the functional recovery of muscle in ESN rats. Furthermore, the re-clustering of Cav2.1 channels after ESN at the nerve terminals corresponded with changes in the Ca2+ distribution. These results indicated that renewal of the Cav2.1 distribution within the presynaptic nerve terminals may be necessary for initiating a proper Ca2+ influx and shortening the latency of muscle contraction during nerve regeneration.
Asunto(s)
Canales de Calcio Tipo N/análisis , Canales de Calcio Tipo N/metabolismo , Calcio/análisis , Calcio/metabolismo , Terminaciones Nerviosas/metabolismo , Terminaciones Nerviosas/patología , Espectrometría de Masa de Ion Secundario , Animales , Cationes Bivalentes/análisis , Cationes Bivalentes/metabolismo , Modelos Animales de Enfermedad , Masculino , Ratas , Ratas WistarRESUMEN
Given the rising prevalence of patients with diabetes and increasing treatment burden for patients with vision-threatening diabetic macular edema (DME), we aimed to explore the efficacy of modified early intensive and treat-and-extend regimen of anti-vascular endothelial growth factor (VEGF) therapy under the Taiwan National Insurance Bureau reimbursement policy. We obtained data on 69 eyes treated with initial 4-monthly intravitreal injections of aflibercept or ranibizumab, plus individualized treat-and-extend regimen. At 12 months, the mean (SD) change in LogMAR best corrected visual acuity from baseline was - 0.28 (0.31) in all eyes, while that in the aflibercept and ranibizumab groups were - 0.30 (0.34) and - 0.25 (0.28), respectively. Central retinal thickness decreased by 137.2 (122.4) in all eyes, 138.1 (134.2) in the aflibercept group, and 136.2 (110.9) in the ranibizumab group. Additionally, the aflibercept group had a lower mean number of injections than the ranibizumab group (8.5 vs. 8.7). The last extended dosing interval of > 12 weeks was 31.0% and 16.7% of the eyes in the aflibercept and ranibizumab groups, respectively. The modified anti-VEGF regimens effectively managed DME in terms of functional and anatomical outcomes, and efficiently reduced the healthcare burden by reducing the number of injections and extending treatment intervals within 12 months.
Asunto(s)
Diabetes Mellitus , Retinopatía Diabética , Edema Macular , Humanos , Ranibizumab , Edema Macular/tratamiento farmacológico , Retinopatía Diabética/tratamiento farmacológico , Retinopatía Diabética/inducido químicamente , Inhibidores de la Angiogénesis , Taiwán , Agudeza Visual , Receptores de Factores de Crecimiento Endotelial Vascular/uso terapéutico , Factores de Crecimiento Endotelial Vascular , Inyecciones Intravítreas , Proteínas Recombinantes de Fusión/uso terapéutico , Diabetes Mellitus/tratamiento farmacológicoRESUMEN
Previously, we found a patient with intractable motor tic disorder, a spectrum of Tourette syndrome (TS), responsive to the ground leaf juice of Clerodendrum inerme (CI). Here, we examined the effect of the ethanol extract of CI leaves (CI extract) on animal behaviors mimicking TS, hyperlocomotion, and sensorimotor gating deficit. The latter is also observed in schizophrenic patients and can be reflected by a disruption of prepulse inhibition of acoustic startle response (PPI) in animal models induced by methamphetamine and NMDA channel blockers (ketamine or MK-801), based on hyperdopaminergic and hypoglutamatergic hypotheses, respectively. CI extract (10-300 mg/kg, i.p.) dose-dependently inhibited hyperlocomotion induced by methamphetamine (2 mg/kg, i.p.) and PPI disruptions induced by methamphetamine, ketamine (30 mg/kg, i.p.), and MK-801 (0.3 mg/kg, i.p.) but did not affect spontaneous locomotor activity, rotarod performance, and grip force. These results suggest that CI extract can relieve hyperlocomotion and improve sensorimotor gating deficit, supporting the therapeutic potential of CI for TS and schizophrenia.
RESUMEN
BACKGROUND AND PURPOSE: The pathophysiological role of α6 -subunit-containing GABAA receptors, which are mainly expressed in cerebellar granule cells, remains unclear. Recently, we demonstrated that hispidulin, a flavonoid isolated from a local herb that remitted a patient's intractable motor tics, attenuated methamphetamine-induced hyperlocomotion in mice as a positive allosteric modulator (PAM) of cerebellar α6 GABAA receptors. Here, using hispidulin and a selective α6 GABAA receptor PAM, the pyrazoloquinolinone Compound 6, we revealed an unprecedented role of cerebellar α6 GABAA receptors in disrupted prepulse inhibition of the startle response (PPI), which reflects sensorimotor gating deficits manifested in several neuropsychiatric disorders. EXPERIMENTAL APPROACH: PPI disruptions were induced by methamphetamine and NMDA receptor antagonists in mice. Effects of the tested compounds were measured in Xenopus oocytes expressing recombinant α6 ß3 γ2S GABAA receptors. KEY RESULTS: Hispidulin given i.p. or by bilateral intracerebellar (i.cb.) injection rescued PPI disruptions induced by methamphetamine, ketamine, MK-801 and phencyclidine. Intracerebellar effects of hispidulin were mimicked by Ro15-4513 and loreclezole (two α6 GABAA receptor PAMs), but not by diazepam (an α6 GABAA receptor-inactive benzodiazepine) and were antagonized by furosemide (i.cb.), an α6 GABAA receptor antagonist. Importantly, Compound 6 (i.p.) also rescued methamphetamine-induced PPI disruption, an effect prevented by furosemide (i.cb.). Both hispidulin and Compound 6 potentiated α6 ß3 γ2S GABAA receptor-mediated GABA currents. CONCLUSIONS AND IMPLICATIONS: Positive allosteric modulation of cerebellar α6 GABAA receptors rescued disrupted PPI by attenuating granule cell activity. α6 GABAA receptor-selective PAMs are potential medicines for treating sensorimotor gating deficits in neuropsychiatric disorders. A mechanistic hypothesis is based on evidence for cerebellar contributions to cognitive functioning including sensorimotor gating.
Asunto(s)
Flavonas/farmacología , Antagonistas de Receptores de GABA-A/farmacología , Trastornos Mentales/tratamiento farmacológico , Inhibición Prepulso/efectos de los fármacos , Receptores de GABA-A/metabolismo , Animales , Flavonas/química , Antagonistas de Receptores de GABA-A/química , Masculino , Trastornos Mentales/metabolismo , Ratones , Ratones Endogámicos ICRRESUMEN
Abnormal expression of chondroitin sulfate has been found in many types of cancer, while its biological functions in hepatocellular carcinoma (HCC) progression remain uninvestigated. Here, we report that chondroitin sulfate synthase 1 (CHSY1), the enzyme that mediates the polymerization step of chondroitin sulfate, is a critical mediator of malignant character in HCC that acts via modulating the activity of the hedgehog signaling. CHSY1 was up-regulated frequently in HCC where these events were associated with worse histologic grade and poor survival. Enforced expression of CHSY1 was sufficient to enhance cell growth, migration, invasion, and epithelial-mesenchymal transition, whereas silencing of CHSY1 suppressed these malignant phenotypes. Mechanistic investigations revealed that the increase of cell surface chondroitin sulfate by CHSY1 promoted sonic hedgehog binding and signaling. Inhibiting hedgehog pathway with vismodegib decreased CHSY1-induced migration, invasion, and lung metastasis of HCC cells, establishing the critical role of hedgehog signaling in mediating the effects of CHSY1 expression. Together, our results indicate that CHSY1 overexpression in HCC contributes to the malignant behaviors in cancer cells, we provide novel insights into the significance of chondroitin sulfate in hedgehog signaling and HCC pathogenesis.