An atlas of itch-associated neural dynamics in the mouse brain

The itch-scratching cycle is mediated by neural dynamics in the brain. However, our understanding of the neural dynamics during this cycle remains limited. In this study, we examine the neural dynamics of 126 mouse brain areas by measuring the calcium signal using fiber photometry. We present numerous response patterns in the mouse brain during the itch-scratching cycle. Interestingly, we find that a group of brain areas exhibit activation only at the end of histamine-induced scratching behavior. Additionally, several brain areas exhibit transient activation at the onset of scratching induced by chloroquine. Both histamine- and chloroquine-induced itch evoke diverse response patterns across the mouse brain. In summary, our study provides a comprehensive dataset for the diverse activity pattern of mouse brain during the itch-scratching cycle, paving the way for further exploration into the neural mechanisms underlying the itch-scratching cycle.

[Fuchs corneal endothelial dystrophy treated with Descemet's stripping without endothelial keratoplasty (DWEK): a case report]

A patient with chief complaint of bilateral progressive visual impairment was diagnosed with Fuchs corneal dystrophy (FECD) in both eyes, macular hole in the left eye, and intraocular lens eye in the right eye. After communication with the patient and his family, they agreed to receive Descemet's stripping without endothelial keratoplasty (DWEK) in the left eye. One year after the operation, the cornea of the left eye was transparent, and the central posterior elastic layer was missing about 4.0 mm diameter. The naked vision of left eye was 0.1, and the correction was not improved. It can be seen that DWEK surgery has a good therapeutic effect on patients with mild FECD.

DXA-measured visceral fat mass and lean body mass reflect abnormal metabolic phenotypes among some obese and nonobese Chinese children and adolescents

BACKGROUND AND AIM

The exact constellation of body composition characteristics among metabolically unhealthy obese (MUO) and nonobese (MUNO) children and adolescents remains unclear. The purpose of this study was to identify the major body composition determinants of metabolically unhealthy phenotypes among Chinese children and adolescents.

METHODS AND RESULTS

We used data from a cross-sectional survey in 2015 that included 1983 children and adolescents aged 6-18 years. Subjects were classified into two phenotypes based on a combination of body mass index (BMI) and metabolic syndrome components. Body composition was measured by dual-energy X-ray absorptiometry (DXA). Among all boys and among adolescent boys, those with MUNO phenotypes displayed significantly higher indices of body composition except for fat mass (FM) percentage and trunk-to-legs FM ratio compared with the metabolically healthy nonobese phenotype (all P < 0.05). MUO individuals had higher arm FM, lean body mass (LBM), and trunk lean mass compared to metabolically healthy obese individuals (all P < 0.05). Visceral fat mass (VFM) and BMI were the major independent determinants of MUNO (VFM, 6- to 9-year-old boys, OR = 1.02, 95% CI = 1.00-1.03, P = 0.021; BMI, 6- to 9-year-old girls, OR = 1.90, 95% CI = 1.31-2.84, P = 0.001; and adolescent boys, OR = 1.34, 95% CI = 1.23-1.44, P < 0.001). LBM was the major independent predictor of MUO among adolescent boys (OR = 1.90, 95% CI = 1.03-1.17, P = 0.003).

CONCLUSIONS

Among children and adolescents, the metabolically unhealthy phenotype was associated with excess of body composition, but with significant differences observed based on age and sex. VFM and LBM derived by DXA can predict the metabolically unhealthy phenotype effectively in specific sex and age groups.

Glucose and forskolin regulate IAPP gene expression through different signal transduction pathways

Molecular mechanisms for the regulation of islet amyloid polypeptide (IAPP) gene expression remain unclear. In the present study, we investigated the effects of glucose and forskolin on IAPP gene regulation in the INS-1 islet beta-cell line. Both glucose and forskolin increased the level of expression of this gene, as measured by Northern blot analysis, and increased IAPP gene transcription in a time- and concentration-dependent manner, as demonstrated in a reporter gene assay. Although inhibition of protein kinase A activity with H-89 eliminated the effect of forskolin on this gene, the glucose effect was unaffected. This supported the predominant use of a protein kinase A-independent signaling pathway for glucose regulation of the IAPP gene. Electrophoretic mobility shift assay further indicated that glucose and forskolin regulated expression of this gene by targeting different elements of the promoter. Mutation of the cAMP regulatory element flanking the IAPP coding region resulted in the loss of most of the forskolin-stimulated IAPP gene promoter activity, whereas glucose-enhanced IAPP gene transcription was unaffected. These results demonstrate parallel and distinct regulatory pathways involved in glucose- and forskolin-induced IAPP gene expression in this model beta-cell system.

Receptor biology and signal transduction

This year has witnessed substantial advances in receptor biology and signal transduction that are relevant to the function and regulation of the healthy pancreas and to the pathogenesis and potential therapy of pancreatitis and pancreatic carcinoma. There has been an expansion in the cast of pancreatic regulatory molecules, now including protease-activated receptors, chemokines, and chemokine receptors. There have been new insights into the cellular distribution and signaling initiated at the classic pancreatic receptors. There have also been dramatic advances in insights into the structure of G protein-coupled receptors, with the first solution of a crystal structure of a member of this superfamily, and into the molecular basis of ligand binding and activation of these important molecules. This will clearly improve the opportunities for the rational design and refinement of receptor-active drugs. In addition to these fundamental advances, there has been renewed attention to the expression, function, and regulation of receptors and signaling pathways in pancreatic cells present in the setting of pancreatitis and pancreatic carcinoma. It is hoped that this will contribute toward earlier diagnosis, more successful therapy, and new chemopreventive strategies for these illnesses.

Acute ethanol exposure attenuates expression of junD in human neuroblastoma cells

This study describes the effects of acute ethanol exposure on the mRNA levels of c-jun,junB and junD in the human neuroblastoma SH-SY5Y cell line. An acute exposure to 100 mM ethanol did not influence the basal and phorbol ester-induced expression of c-jun and junB, whereas the basal mRNA level of junD was attenuated by 30%. This effect was dose- and time-dependent with maximal inhibition being detected 2 h after 100 mM ethanol treatment and the mRNA levels gradually returned towards normal afterwards. Ethanol also inhibited phorbol ester-induced expression of junD. The fact that ethanol did not influence degradation of the junD mRNA suggests that acute ethanol suppresses the transcription of the gene. These results indicate that acute ethanol exerts different effects on expression of Jun transcription factors, suggesting that as compared to c-jun and junB, the junD gene may be more sensitive to acute ethanol treatment in neuronal cells.

Stimulation of muscarinic receptors induces expression of individual fos and jun genes through different transduction pathways

The transduction pathways coupling muscarinic receptors to induction of fos and jun genes were investigated in neuroblastoma SH-SY5Y cells. Stimulation with carbachol induced expression of c-fos, fosB, c-jun, junB, and junD. This effect was abolished by pretreatment with atropine, indicating an involvement of muscarinic receptors. These genes were also induced by activation of protein kinase C with phorbol ester or by elevating the intracellular Ca2+ concentration with a Ca2+ ionophore. The Ca2+ effect was inhibited by KN-62, suggesting an induction through Ca2+/calmodulin-dependent kinase II. Inhibition of protein kinase C with GF109203X suppressed the carbachol-stimulated increase in mRNA levels of c-fos, fosB, and junB by approximately 70% but had only minor effects on the expression of c-jun and junD. On the other hand, preincubation with KN-62 attenuated the carbachol-induced increase in c-jun and junD expression by 70% but had no effect on c-fos, fosB, and junB mRNA levels. Simultaneous inhibition of both protein kinase C and Ca2+/calmodulin-dependent kinase II completely abolished the carbachol-stimulated expression of c-jun and junD, but c-fos, fosB, and junB were still expressed to a certain extent under this condition. Comparison of the inhibitory effects of GF109203X and Gö 6976 suggests the involvement of classical protein kinase C isozymes in muscarinic receptor-stimulated expression of fos and jun genes. These results demonstrate that the muscarinic receptor-induced expression of individual fos and jun genes is regulated via different pathways, primarily protein kinase C or Ca2+/calmodulin-dependent kinase II.

Ethanol exposure potentiates fosB and junB expression induced by muscarinic receptor stimulation in neuroblastoma SH-SY5Y cells

Muscarinic receptor stimulation and activation of protein kinase C cause an increase in fosB and junB transcripts in human neuroblastoma SH-SY5Y cells. In this study, the effect of long-term ethanol exposure on these events was investigated. Carbachol-stimulated fosB and junB expression was elevated in ethanol-exposed cells compared with control cells. The potentiation was time- and dose-dependent on ethanol. Preincubation with muscarinic antagonists or protein kinase C inhibitor demonstrated that the carbachol-stimulated increase in fosB and junB mRNA levels was primarily mediated via M1 receptors and dependent on the activity of protein kinase C in both control and ethanol-exposed cells. Long-term ethanol exposure did not influence the expression of fosB and junB induced by activation of protein kinase C with phorbol ester. These results demonstrate that the muscarinic receptor-stimulated fosB and junB expression is sensitive to ethanol exposure in SH-SY5Y cells, suggesting that these genes participate in the regulation of neuronal function in response to chronic ethanol treatment.

Effects of ethanol on muscarinic receptor-stimulated c-fos expression in human neuroblastoma cells

The effect of ethanol exposure on muscarinic receptor-stimulated expression of c-fos was investigated in SH-SY5Y cells. Four days of ethanol exposure enhanced carbachol-stimulated c-fos mRNA expression, analyzed with Northern blot, and Fos/AP-1 binding activity, measured with gel mobility super shift assay. Pre-incubation with muscarinic antagonists or the protein kinase C inhibitor GF109203X demonstrated that, in both control and ethanol-treated cells, carbachol-induced c-fos expression was mediated via muscarinic M1 receptors and to a large extent through protein kinase C. However, phorbol ester-induced c-fos expression was unaffected in ethanol-treated cells. Acute exposure to ethanol caused a suppression of both carbachol- and phorbol ester-stimulated c-fos expression. These results demonstrate that muscarinic receptor-stimulated gene expression is sensitive to both acute and long-term ethanol exposure.

Ethanol exposure increases expression of c-jun and junD in human neuroblastoma cells

The aim of this study was to investigate the effect of ethanol exposure on the expression of fos and jun genes. Exposure of human neuroblastoma SH-SY5Y cells to ethanol for 2-4 days caused a dose-dependent increase in c-jun and junD mRNA levels, whereas mRNAs for c-fos, fosB and junB were not detectable in control or ethanol-treated cells. Four days of ethanol exposure also enhanced the AP-1 binding activity. Experiments with actinomycin D demonstrated that ethanol did not influence the degradation of c-jun and junD mRNAs. These results demonstrate that long-term exposure to ethanol increases c-jun and junD expression. This effect may be one of the mechanisms through which ethanol influences the gene regulatory system in neuronal cells.