Tobacco smokers titrate their nicotine intake to avoid its noxious effects, sensitivity to which may influence vulnerability to tobacco dependence, yet mechanisms of nicotine avoidance are poorly understood. Here, we show that nicotine activates glucagon-like peptide-1 (GLP-1) neurons in the nucleus tractus solitarius (NTS). The antidiabetic drugs sitagliptin and exenatide, which inhibit GLP-1 breakdown and stimulate GLP-1 receptors (GLP-1Rs), respectively, decrease nicotine intake in mice. Chemogenetic activation of GLP-1 neurons in NTS similarly decreases nicotine intake. Conversely, Glp1r knockout mice consume greater quantities of nicotine than wild-type mice. Using optogenetic stimulation, we show that GLP-1 excites medial habenular (MHb) projections to interpeduncular nucleus (IPN). Activation of GLP-1Rs in the MHb-IPN circuit abolishes nicotine reward and decreases nicotine intake, whereas their knockdown or pharmacological blockade increases intake. GLP-1 neurons may therefore serve as "satiety sensors" for nicotine that stimulate habenular systems to promote nicotine avoidance before its aversive effects are encountered.Tobacco smoking is the primary cause of preventable death and disease in developed nations, costing approximately $100 billion in annual health care expenses in the United Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use:
AimsAn ongoing outbreak of 2019 novel coronavirus (SARS-CoV-2) diseases (COVID-19) has been spreading in multiple countries. One of the reasons for the rapid spread is that the virus can be transmitted from infected individuals without symptoms. Revealing the pathological features of early phase COVID-19 pneumonia is important to the understanding of its pathogenesis. The aim of this study was to explore pulmonary pathology of early phase COVID-19 pneumonia in a patient with a benign lung lesion. Methods and resultsWe analyzed the pathological changes of lung tissue from a 55-year-old female patient with early phase SARS-CoV-2 infection. In this case, right lower lobectomy was performed for a benign pulmonary nodule. Detailed clinical, laboratory and radiological data were also described. This case was confirmed to have preoperative SARS-CoV-2 infection by real-time RT-PCR and RNA in situ hybridization on surgically removed lung tissues. Histologically, COVID-19 pneumonia was characterized by exudative inflammation. The closer to the visceral pleura, the more severe the exudation of monocytes and lymphocytes. Perivascular inflammatory infiltration, intraalveolar multinucleated giant cells, pneumocyte hyperplasia and intracytoplasmic viral-like inclusion bodies were seen. However, fibrinous exudate and hyaline membrane formation, which were typical pulmonary features of SARS pneumonia, were not evident in this case. Immunohistochemical staining results showed that an abnormal accumulation of CD4+ helper T lymphocytes and CD163+ M2 macrophages in the lung tissue. Accepted ArticleThis article is protected by copyright. All rights reserved ConclusionThe results highlighted the pulmonary pathological changes of early phase SARS-CoV-2 infection and suggested a role of immune dysfunction in the pathogenesis of COVID-19 pneumonia.
Diabetes is far more prevalent in smokers than non-smokers, but little is known about underlying mechanisms of vulnerability. Here, we show that the diabetes-associated gene Tcf7l2 is densely expressed in the medial habenula (mHb), where it regulates the function of nicotinic acetylcholine receptors. Inhibition of Tcf7l2 signaling in the mHb increases nicotine intake in mice and rats. Nicotine elevates blood glucose levels through a Tcf7l2-dependent stimulatory action on the mHb. Virus tracing identifies a polysynaptic connection from the mHb to the pancreas, and wild-type rats with a history of nicotine consumption show elevated circulating levels of glucagon and insulin and diabetes-like dysregulation of blood glucose homeostasis. In contrast, Tcf7l2 mut rats are resistant to these actions of nicotine. Our findings suggest that Tcf7l2 regulates the stimulatory actions of nicotine on a habenula-pancreas axis that links the addictive properties of nicotine to its diabetes-promoting actions.
Despite the importance of the long non-coding RNAs (lncRNAs) in regulating biological functions, the expression profiles of lncRNAs in the sub-regions of the mammalian brain and neuronal populations remain largely uncharacterized. By analyzing RNASeq datasets, we demonstrate region specific enrichment of populations of lncRNAs and mRNAs in the mouse hippocampus and pre-frontal cortex (PFC), the two major regions of the brain involved in memory storage and neuropsychiatric disorders. We identified 2759 lncRNAs and 17,859 mRNAs in the hippocampus and 2561 lncRNAs and 17,464 mRNAs expressed in the PFC. The lncRNAs identified correspond to ~14% of the transcriptome of the hippocampus and PFC and ~70% of the lncRNAs annotated in the mouse genome (NCBIM37) and are localized along the chromosomes as varying numbers of clusters. Importantly, we also found that a few of the tested lncRNA-mRNA pairs that share a genomic locus display specific co-expression in a region-specific manner. Furthermore, we find that sub-regions of the brain and specific neuronal populations have characteristic lncRNA expression signatures. These results reveal an unexpected complexity of the lncRNA expression in the mouse brain.
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