Effects and regulatory pathway of proopinmelanocortin on feeding habit domestication in mandarin fish.

Proopiomelanocortin (POMC) is a hormone precursor, and has been reported to participate in domestication. However, its effects on feeding habit domestication in fish are poorly understood. Mandarin fish (Siniperca chuatsi) feeds solely on live prey fish since first-feeding. In the present study, the high expression of pomc in mandarin fish, both the pomc siRNA and MC4R inhibitor treatments increased the success rate of domestication from live prey fish to dead prey fish and food intake of dead prey fish, suggesting the role of pomc on the special feeding habit of live prey fish in mandarin fish. In addition, one c-fos binding site was identified in the region that from -1053 bp to -931 bp upstream of the transcription start site of pomc, and this region exhibited positive promoter activity. The mandarin fish brain cells treated with c-fos siRNA displayed suppressed pomc mRNA expression, indicating that c-fos positively regulated pomc expression. Furthermore, the mRNA expression of c-fos was higher in the mandarin fish which were more difficult to domesticate. The results of ChIP assay and inhibitor treatment confirmed that the activation of c-fos gene by histone H3K4me3 was catalyzed by Setd1b in mandarin fish. Three open peaks were found at the upstream regulatory region of setd1b by ATAC-seq, and the mRNA expression of setd1b was higher in the mandarin fish which were more difficult to domesticate. These results indicated that Setd1b could methylate histone H3K4 to activate the c-fos transcription, maintaining the high expression of pomc, which might contribute to the special feeding habit of mandarin fish.

Transcriptome sequencing and metabolome analysis of food habits domestication from live prey fish to artificial diets in mandarin fish (Siniperca chuatsi).

BACKGROUND: As economical traits, food habits domestication can reduce production cost in aquaculture. However, the molecular mechanism underlying food habits domestication has remained elusive. Mandarin fish (Siniperca chuatsi) only feed on live prey fish and refuse artificial diets. In the present study, we domesticated mandarin fish to feed on artificial diets. The two groups were obtained, the fish did not eat artificial diets or ate artificial diets during all of the three domestication processes, named Group W or X, respectively. RESULTS: Using transcriptome and metabolome analysis, we investigated the differentially expressed genes and metabolites between the two groups, and found three common pathways related to food habit domestication, including retinol metabolism, glycerolipid metabolism, and biosynthesis of unsaturated fatty acids pathways. Furthermore, the western blotting and bisulfite sequencing PCR analysis were performed. The gene expression of TFIIF and histone methyltransferase ezh1 were significantly increased and decreased in the fish of Group X, respectively. The total DNA methylation levels of TFIIF gene and tri-methylation of histone H3 at lysine 27 (H3K27me3) were significantly higher and lower in the fish of Group X, respectively. CONCLUSION: It was speculated that mandarin fish which could feed on artificial diets, might be attributed to the lower expression of ezh1, resulting in the decreased level of H3K27me3 and increased level of DNA methylation of TFIIF gene. The high expression of TFIIF gene might up-regulate the expression of genes in retinol metabolism, glycerolipid metabolism and glycerophosphoric metabolism pathways. Our study indicated the relationship between the methylation of DNA and histone and food habits domestication, which might be a novel molecular mechanism of food habits domestication in animals.

Histone Methylation of H3K4 Involved in the Anorexia of Carnivorous Mandarin Fish (Siniperca chuatsi) After Feeding on a Carbohydrate-Rich Diet.

Food intake of carnivorous fish decreases after feeding on a carbohydrate-rich diet. However, the molecular mechanism underlying the anorexia caused by high-carbohydrate diets has remained elusive. We domesticated the mandarin fish to feed on carbohydrate-rich (8%) diets. After 61 days of feeding, several fish (Group A) fed well on artificial diets during the whole feeding period; the other fish (Group B) fed well on artificial diets at the beginning of the feeding period, with their food intake then decreasing to half (anorexia) and then to zero for 5 days; and, finally, a negative control (Group C) fed on live prey fish throughout the experimental process. The plasma glucose was significantly higher in the mandarin fish of Group B than in those of Group A, whereas levels of hepatic glycogen and plasma triglyceride were significantly lower. Using transcriptome sequencing, we investigated the differentially expressed genes between Groups A and B and excluded the genes that were not differentially expressed between Groups A and C. The activation of mTOR and Jak/STAT pathways were found in the mandarin fish with anorexia, which was consistent with the higher expression levels of pepck and pomc genes. We found a higher expression of histone methyltransferase setd1b gene and an increased histone H3 tri-methylated at lysine 4 (H3K4me3) in the fish of Group B. Furthermore, using ChIP assay and inhibitor treatment, we found that the up-regulated H3K4me3 could activate pepck expression, which might have contributed to the hyperglycemia and anorexia in the mandarin fish that fed on carbohydrate-rich diets. Our study initially indicated a link between histone methylation and pepck expression, which might be a novel regulatory mechanism of fish who are fed a carbohydrate-rich diet.

Extracellular Matrix-receptor Interaction Signaling Genes Associated with Inferior Breast Cancer Survival.

BACKGROUND/AIM: Breast cancer is a common type of cancer in women, and metastasis frequently leads to therapy failure. Using next-generation sequencing (NGS), we aspired to identify the optimal differentially expressed genes (DEGs) for use as prognostic biomarkers for breast cancer. MATERIALS AND METHODS: NGS was used to determine transcriptome profiles in breast cancer tissues and their corresponding adjacent normal tissues from three patients with breast cancer. RESULTS: Herein, 15 DEGs (fold change >4 and <0.25) involved in extracellular matrix (ECM)-receptor interaction signaling were identified through NGS. Among them, our data indicated that high HMMR expression levels were correlated with a poor pathological stage (p<0.001) and large tumor size (p<0.001), whereas high COL6A6 and Reelin (RELN) expression levels were significantly correlated with an early pathological stage (COL6A6: p=0.003 and RELN: p<0.001). Multivariate analysis revealed that high HMMR and SDC1 expression levels were significantly correlated with poor overall survival (OS; HMMR: adjusted hazard ratio [aHR] 1.93, 95% confidence interval [CI]=1.10-3.41, p=0.023; SDC1: [aHR] 2.47, 95%CI=1.28-4.77, p=0.007) for breast cancer. Combined, the effects of HMMR and SDC1 showed a significant correlation with poor OS for patients with breast cancer (high expression for both HMMR and SDC1: [aHR] 3.29, 95%CI=1.52-7.12, p=0.003). CONCLUSION: These findings suggest that HMMR and SDC1 involved in the ECM-receptor interaction signaling pathway could act as effective independent prognostic biomarkers for breast ductal carcinoma.

Expression of Brain-derived Neurotrophic Factor and Tyrosine Kinase B in Cerebellum of Poststroke Depression Rat Model.

BACKGROUND: The pathophysiology of poststroke depression (PSD) remains elusive because of its proposed multifactorial nature. Accumulating evidence suggests that brain-derived neurotrophic factor (BDNF) plays a key role in the pathophysiology of depression and PSD. And the cerebellar dysfunction may be important in the etiology of depression; it is not clear whether it also has a major effect on the risk of PSD. This study aimed to explore the expression of BDNF and high-affinity receptors tyrosine kinase B (TrkB) in the cerebellum of rats with PSD. METHODS: The rat models with focal cerebral ischemic were made using a thread embolization method. PSD rat models were established with comprehensive separate breeding and unpredicted chronic mild stress (UCMS) on this basis. A normal control group, depression group, and a stroke group were used to compare with the PSD group. Thirteen rats were used in each group. Immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR) for detecting the expression of BDNF and TrkB protein and mRNA in the cerebellum were used at the 29 th day following the UCMS. RESULTS: Compared with the normal control group and the stroke group, the number of BDNF immunoreactive (IR) positive neurons was less in the PSD group (P < 0.05). Furthermore, the number of TrkB IR positive cells was significantly less in the PSD group than that in the normal control group (P < 0.05). The gene expression of BDNF and TrkB in the cerebellum of PSD rats also decreased compared to the normal control group (P < 0.05). CONCLUSIONS: These findings suggested a possible association between expression of BDNF and TrkB in the cerebellum and the pathogenesis of PSD.

[Pollution Level and Sources of Organic Phosphorus Esters in Airborne PM2.5 in Chengdu City].

Organic phosphorus esters ( OPEs ) in atmospheric PM2.5 in Chengdu city was quantitatively determined by using gas chromatography-mass spectrometry. The distribution characteristic was discussed, back trajectory model and correlation analysis were used to study the sources of OPEs in PM2.5 in Chengdu city. The results showed that the annual average concentration of Σ7OPEs in atmospheric PM2.5 in Chengdu city was 6.46 ng x m(-3) for the urban site and was 9.38 ng x m(-3) for the suburb site. Due to the waste material recycling industries in the suburb area and the perennial dominant wind direction in Chengdu, the concentration of Σ7OPEs at suburb site was higher than that at urban site (P = 0.013). The atmospheric mixed degree influenced the distribution of OPEs in rural and urban area. The source of Σ7OPEs in atmospheric PM2.5 in Chengdu city was mainly from endogenous pollution which was mainly affected by the local sources around the samoling sites. while the contribution of the exogenous pollution was small.