Impaired D2 receptor-dependent dopaminergic transmission in prefrontal cortex of awake mouse model of Parkinson's disease.

The loss-of-function mutation in PARK7/DJ-1 is one of the most common causes of autosomal recessive Parkinson's disease, and patients carrying PARK7 mutations often exhibit both a progressive movement disorder and emotional impairment, such as anxiety. However, the causes of the emotional symptom accompanying PARK7-associated and other forms of Parkinson's disease remain largely unexplored. Using two-photon microscopic Ca2+ imaging in awake PARK7-/- and PARK7+/+ mice, we found that (i) PARK7-/- neurons in the frontal association cortex showed substantially higher circuit activity recorded as spontaneous somatic Ca2+ signals; (ii) both basal and evoked dopamine release remained intact, as determined by both electrochemical dopamine recordings and high performance liquid chromatography in vivo; (iii) D2 receptor expression was significantly decreased in postsynaptic frontal association cortical neurons, and the hyper-neuronal activity were rescued by D2 receptor intervention using either local pharmacology or viral D2 receptor over-expression; and (iv) PARK7-/- mice showed anxiety-like behaviours that were rescued by either local D2 receptor pharmacology or overexpression. Thus, for first time, we demonstrated a robust D2 receptor-dependent phenotype of individual neurons within the prefrontal cortex circuit in awake parkinsonian mice that linked with anxiety. Our work sheds light on early-onset phenotypes and the mechanisms underlying Parkinson's disease by imaging brain circuits in an awake mouse model.

Stretch-induced Ca2+ independent ATP release in hippocampal astrocytes.

KEY POINTS: Similar to neurons, astrocytes actively participate in synaptic transmission via releasing gliotransmitters. The Ca2+ -dependent release of gliotransmitters includes glutamate and ATP. Following an 'on-cell-like' mechanical stimulus to a single astrocyte, Ca2+ independent single, large, non-quantal, ATP release occurs. Astrocytic ATP release is inhibited by either selective antagonist treatment or genetic knockdown of P2X7 receptor channels. Our work suggests that ATP can be released from astrocytes via two independent pathways in hippocampal astrocytes; in addition to the known Ca2+ -dependent vesicular release, larger non-quantal ATP release depends on P2X7 channels following mechanical stretch. ABSTRACT: Astrocytic ATP release is essential for brain functions such as synaptic long-term potentiation for learning and memory. However, whether and how ATP is released via exocytosis remains hotly debated. All previous studies of non-vesicular ATP release have used indirect assays. By contrast, two recent studies report vesicular ATP release using more direct assays. In the present study, using patch clamped 'ATP-sniffer cells', we re-investigated astrocytic ATP release at single-vesicle resolution in hippocampal astrocytes. Following an 'on-cell-like' mechanical stimulus of a single astrocyte, a Ca2+ independent single large non-quantal ATP release occurred, in contrast to the Ca2+ -dependent multiple small quantal ATP release in a chromaffin cell. The mechanical stimulation-induced ATP release from an astrocyte was inhibited by either exposure to a selective antagonist or genetic knockdown of P2X7 receptor channels. Functional P2X7 channels were expressed in astrocytes in hippocampal brain slices. Thus, in addition to small quantal ATP release, larger non-quantal ATP release depends on P2X7 channels in astrocytes.

An ACC-VTA-ACC positive-feedback loop mediates the persistence of neuropathic pain and emotional consequences.

The central mechanisms underlying pain chronicity remain elusive. Here, we identify a reciprocal neuronal circuit in mice between the anterior cingulate cortex (ACC) and the ventral tegmental area (VTA) that mediates mutual exacerbation between hyperalgesia and allodynia and their emotional consequences and, thereby, the chronicity of neuropathic pain. ACC glutamatergic neurons (ACCGlu) projecting to the VTA indirectly inhibit dopaminergic neurons (VTADA) by activating local GABAergic interneurons (VTAGABA), and this effect is reinforced after nerve injury. VTADA neurons in turn project to the ACC and synapse to the initial ACCGlu neurons to convey feedback information from emotional changes. Thus, an ACCGlu-VTAGABA-VTADA-ACCGlu positive-feedback loop mediates the progression to and maintenance of persistent pain and comorbid anxiodepressive-like behavior. Disruption of this feedback loop relieves hyperalgesia and anxiodepressive-like behavior in a mouse model of neuropathic pain, both acutely and in the long term.

Cocaine induces locomotor sensitization through a dopamine-dependent VTA-mPFC-FrA cortico-cortical pathway in male mice.

As a central part of the mammalian brain, the prefrontal cortex (PFC) has been implicated in regulating cocaine-induced behaviors including compulsive seeking and reinstatement. Although dysfunction of the PFC has been reported in animal and human users with chronic cocaine abuse, less is known about how the PFC is involved in cocaine-induced behaviors. By using two-photon Ca2+ imaging to simultaneously record tens of intact individual networking neurons in the frontal association cortex (FrA) in awake male mice, here we report that a systematic acute cocaine exposure decreased the FrA neural activity in mice, while the chemogenetic intervention blocked the cocaine-induced locomotor sensitization. The hypoactivity of FrA neurons was critically dependent on both dopamine transporters and dopamine transmission in the ventromedial PFC (vmPFC). Both dopamine D1R and D2R neurons in the vmPFC projected to and innervated FrA neurons, the manipulation of which changed the cocaine-induced hypoactivity of the FrA and locomotor sensitization. Together, this work demonstrates acute cocaine-induced hypoactivity of FrA neurons in awake mice, which defines a cortico-cortical projection bridging dopamine transmission and cocaine sensitization.

Deep Learning-Based Ultrasound Combined with Gastroscope for the Diagnosis and Nursing of Upper Gastrointestinal Submucous Lesions.

The study focused on the diagnostic value of deep learning-based ultrasound combined with gastroscope examination for upper gastrointestinal submucous lesions and nursing. A total of 104 patients with upper gastrointestinal submucous lesions diagnosed in hospital were selected as the research subjects. In this study, the feed forward denoising convulsive neural network (DnCNN) was improved, and the n-DnCNN model was designed and applied to ultrasonic image processing. The peak signal-to-noise ratio (PSNR) and structural similarity (SSIM) of Gaussian filtering, NL-means, and DnCNN were then compared with n-DnCNN. Subsequently, the distribution and types of submucosal lesions in different parts of the upper digestive tract were analyzed by ultrasound combined with gastroscope and gastroscope examination alone, and the diagnostic performance of this method was evaluated. The results showed that the average PSNR and SSIM of the n-DnCNN model were 33.01 dB and 0.87, respectively, which were significantly higher than GF, NL-means, and DnCNN algorithms, and the difference was statistically significant (P < 0.05). Of the 116 lesions detected, 49 were located in the esophagus (42.24%), 52 in the stomach (44.83%), and 15 in the duodenum (12.93%). Of the 49 esophageal submucosal lesions, 6.12% were located in the upper esophagus, 55.1% in the middle esophagus, and 38.79% in the lower esophagus, and the difference was statistically significant (P < 0.05). Of the gastric submucosal lesions, the lesions in the gastric cardia were significantly less than in other parts, and the difference was statistically significant (P < 0.05). The accuracy of ultrasound combined with gastroscope in the diagnosis of upper gastrointestinal submucous episodes was 82.32%, higher than that of gastroscope examination, and the difference was statistically significant (P < 0.05). In conclusion, the n-DnCNN model has a good noise reduction effect, and the obtained image is of high quality. Ultrasound combined with gastroscope examination can effectively improve the accuracy of diagnosis of upper gastrointestinal submucous lesions.

Astrocytic Piezo1-mediated mechanotransduction determines adult neurogenesis and cognitive functions.

Adult brain activities are generally believed to be dominated by chemical and electrical transduction mechanisms. However, the importance of mechanotransduction mediated by mechano-gated ion channels in brain functions is less appreciated. Here, we show that the mechano-gated Piezo1 channel is expressed in the exploratory processes of astrocytes and utilizes its mechanosensitivity to mediate mechanically evoked Ca2+ responses and ATP release, establishing Piezo1-mediated mechano-chemo transduction in astrocytes. Piezo1 deletion in astrocytes causes a striking reduction of hippocampal volume and brain weight and severely impaired (but ATP-rescuable) adult neurogenesis in vivo, and it abolishes ATP-dependent potentiation of neural stem cell (NSC) proliferation in vitro. Piezo1-deficient mice show impaired hippocampal long-term potentiation (LTP) and learning and memory behaviors. By contrast, overexpression of Piezo1 in astrocytes sufficiently enhances mechanotransduction, LTP, and learning and memory performance. Thus, astrocytes utilize Piezo1-mediated mechanotransduction mechanisms to robustly regulate adult neurogenesis and cognitive functions, conceptually highlighting the importance of mechanotransduction in brain structure and function.

Cocaine increases quantal norepinephrine secretion through NET-dependent PKC activation in locus coeruleus neurons.

The norepinephrine neurons in locus coeruleus (LC-NE neurons) are essential for sleep arousal, pain sensation, and cocaine addiction. According to previous studies, cocaine increases NE overflow (the profile of extracellular NE level in response to stimulation) by blocking the NE reuptake. NE overflow is determined by NE release via exocytosis and reuptake through NE transporter (NET). However, whether cocaine directly affects vesicular NE release has not been directly tested. By recording quantal NE release from LC-NE neurons, we report that cocaine directly increases the frequency of quantal NE release through regulation of NET and downstream protein kinase C (PKC) signaling, and this facilitation of NE release modulates the activity of LC-NE neurons and cocaine-induced stimulant behavior. Thus, these findings expand the repertoire of mechanisms underlying the effects of cocaine on NE (pro-release and anti-reuptake), demonstrate NET as a release enhancer in LC-NE neurons, and provide potential sites for treatment of cocaine addiction.

[Relevant factors and management skills of difficult tracheostomy].

Tracheotomy is a routine operation in otolaryngology head and neck surgery, and its clinical application is very extensive. However, in the actual clinical work, there are always various reasons leading to tracheotomy difficulties, endangering the lives of patients. At present, there is no uniform standard for the evaluation of difficult tracheotomy, and its treatment skills are also confused. This article reviews the related factors of difficult tracheotomy in clinic, and puts forward the corresponding management skills.

Reply to "TRPA1-dependent calcium transients and CGRP release in DRG neurons require extracellular calcium".

In this issue, Gebhardt et al. (2020. J. Cell Biol.https://doi.org/10.1083/jcb.201702151) express interest in our recently published work (Shang et al. 2016. J. Cell Biol.https://doi.org/10.1083/jcb.201603081). Here, we would like to address their concerns regarding the lysosomal TRPA1-mediated intracellular calcium transients in dorsal root ganglion neurons.

Differential Co-release of Two Neurotransmitters from a Vesicle Fusion Pore in Mammalian Adrenal Chromaffin Cells.

Co-release of multiple neurotransmitters from secretory vesicles is common in neurons and neuroendocrine cells. However, whether and how the transmitters co-released from a single vesicle are differentially regulated remains unknown. In matrix-containing dense-core vesicles (DCVs) in chromaffin cells, there are two modes of catecholamine (CA) release from a single DCV: quantal and sub-quantal. By combining two microelectrodes to simultaneously record co-release of the native CA and ATP from a DCV, we report that (1) CA and ATP were co-released during a DCV fusion; (2) during kiss-and-run (KAR) fusion, the co-released CA was sub-quantal, whereas the co-released ATP was quantal; and (3) knockdown and knockout of the DCV matrix led to quantal co-release of both CA and ATP even in KAR mode. These findings strongly imply that, in contrast to sub-quantal CA release in chromaffin cells, fast synaptic transmission without transmitter-matrix binding is mediated exclusively via quantal release in neurons.

Polymorphism in the promoter region of lncRNA GAS5 is functionally associated with the risk of gastric cancer.

BACKGROUND AND AIMS: Previous studies showed that down-regulation of GAS5 was involved in the development of gastric cancer (GC). However, the regulatory mechanism of down-expressed GAS5 in GC remains obscure. We aimed to investigate the role of rs145204276 of GAS5 in the development and metastasis process of GC. METHODS: 853 GC patients and 954 healthy controls were recruited. The variant rs145204276 was genotyped and the Chi2 test was used to compare the frequency of the genotype and the allele between the patients and the controls. Odds ratio (OR) and 95% confidence intervals (95% CIs) were calculated to estimate the association of rs145204276 with the risk of development and metastasis of GC. RESULTS: Patients were found to have significantly lower rate of genotype del/del than the controls (7.2% vs. 8.9%, P=0.016). The allele del was significantly associated with a decreased risk of GC (26.4% vs. 30.7%, P=0.005) with an OR of 0.81 (95% CI=0.70-0.94). Patients with allele del were less likely to develop lymph node metastasis (P=0.01), with an OR of 0.75 (95% CI=0.60-0.93). Comparably, rs145204276 was also significantly associated with a decreased risk of distant metastasis of GC (P=0.007; OR=0.55). CONCLUSION: We confirmed that rs145204276 of GAS5 is a functional variant associated with the susceptibility and metastasis of GC. It plays a protective role in the development of GC possibly through the regulation of GAS5.

Synaptotagmin-11 is a critical mediator of parkin-linked neurotoxicity and Parkinson's disease-like pathology.

Loss-of-function mutations in Parkin are the most common causes of autosomal recessive Parkinson's disease (PD). Many putative substrates of parkin have been reported; their pathogenic roles, however, remain obscure due to poor characterization, particularly in vivo. Here, we show that synaptotagmin-11, encoded by a PD-risk gene SYT11, is a physiological substrate of parkin and plays critical roles in mediating parkin-linked neurotoxicity. Unilateral overexpression of full-length, but not C2B-truncated, synaptotagmin-11 in the substantia nigra pars compacta (SNpc) impairs ipsilateral striatal dopamine release, causes late-onset degeneration of dopaminergic neurons, and induces progressive contralateral motor abnormalities. Mechanistically, synaptotagmin-11 impairs vesicle pool replenishment and thus dopamine release by inhibiting endocytosis. Furthermore, parkin deficiency induces synaptotagmin-11 accumulation and PD-like neurotoxicity in mouse models, which is reversed by SYT11 knockdown in the SNpc or knockout of SYT11 restricted to dopaminergic neurons. Thus, PD-like neurotoxicity induced by parkin dysfunction requires synaptotagmin-11 accumulation in SNpc dopaminergic neurons.