Caveolin-1 and MLRs: A potential target for neuronal growth and neuroplasticity after ischemic stroke
INTERNATIONAL JOURNAL OF MEDICAL SCIENCES
Authors: Zhong, Wei; Huang, Qianyi; Zeng, Liuwang; Hu, Zhiping; Tang, Xiangqi
Abstract
Ischemic stroke is a leading cause of morbidity and mortality worldwide. Thrombolytic therapy, the only established treatment to reduce the neurological deficits caused by ischemic stroke, is limited by time window and potential complications. Therefore, it is necessary to develop new therapeutic strategies to improve neuronal growth and neurological function following ischemic stroke. Membrane lipid rafts (MLRs) are crucial structures for neuron survival and growth signaling pathways. Caveolin-1 (Cav-1), the main scaffold protein present in MLRs, targets many neural growth proteins and promotes growth of neurons and dendrites. Targeting Cav-1 may be a promising therapeutic strategy to enhance neuroplasticity after cerebral ischemia. This review addresses the role of Cav-1 and MLRs in neuronal growth after ischemic stroke, with an emphasis on the mechanisms by which Cav-1/MLRs modulate neuroplasticity via related receptors, signaling pathways, and gene expression. We further discuss how Cav-1/MLRs may be exploited as a potential therapeutic target to restore neuroplasticity after ischemic stroke. Finally, several representative pharmacological agents known to enhance neuroplasticity are discussed in this review.
IC/BPS-associated alterations of M2 and M3 muscarinic acetylcholine receptor trafficking in human detrusor
NEUROUROLOGY AND URODYNAMICS
Authors: Berndt-Paetz, Mandy; Herbst, Luise; Weimann, Annett; Gonsior, Andreas; Stolzenburg, Jens-Uwe; Neuhaus, Jochen
Abstract
Aims To explore caveolae- and clathrin-mediated internalization of muscarinic M2 and M3 receptors, recycling and degradation in formalin-fixed paraffin-embedded detrusor sections; to study alterations possibly involved in the pathophysiology of the bladder functional disorder, interstitial cystitis/bladder pain syndrome (IC/BPS). Materials and Methods Samples of IC/BPS (n = 11) and cystectomy patients (n = 11) were analyzed. Proximity ligation assay (PLA) was used to detect interactions of M2 and M3 with endocytotic regulators (Cav-1, clathrin, Rab7, and Rab11) by Cy3 labeling. Analyses of three-dimensional (3D)-reconstructed z-stacks (63 x Oil 1.4) were done with Huygens software. We determined the object density for quantification and assessed membrane localization. Results Receptor/protein complexes were detected as well-demarcated 3D objects. Interactions of M2 with Cav-1, clathrin, Rab11, and Rab7 were significantly increased in IC/BPS. M3/clathrin and M3/Rab11 complexes were higher in IC/BPS, while M3/Cav-1 and M3/Rab7 were not. A significant shift of complexes from the membrane to cytoplasm was observed in conjunction with increased internalization via clathrin vesicles or caveolae in IC/BPS. Conclusions High numbers of M3/clathrin and M3/Rab11 complexes reflect the well-documented clathrin-mediated desensitization of M3 and speak in favor with enhanced receptor protein expression in IC/BPS. Increased amounts of M2/Cav-1, M2/clathrin, and M2/Rab11 complexes represent altered M2 internalization and recycling leading to high abundance in IC/BPS. In this regard, caveolae-localized M2 could be possibly associated with the activation of nitric oxide (NO) synthase and NO production.