Exercise Associated Genes in Rat Colon Mucosa: Upregulation of Ornithin Decarboxylase-1

Determination of reference genes for ovine pulmonary adenocarcinoma infected lung tissues using RNA-seq transcriptome profiling

Ovine pulmonary adenocarcinoma (OPA) is a globally occurring tumor of lung epithelium which seriously affects the development of sheep farming. In our research, lung tissues of 3 naturally infected OPA individuals and 3 healthy individuals (2-4 years old) were collected. RNA was extracted for transcriptome analysis and reference gene selection. According to transcriptome analysis, 7 candidate reference genes (eukaryotic translation initiation factor 1, EIF1; glyceraldehyde-3-phosphate dehydrogenase, GAPDH; beta-actin, ACTB; GABA Type A receptor-associated protein, GABARAP; activating transcription factor 4, ATF4; ribosomal protein S15, RPS15; and Y-Box binding protein 1, YBX1) showed fragments per kilobase of transcript per million fragments mapped (FPKM) values > 200.0 and standard errors of the means (SEM) < 20.0. Expression of the above candidate reference genes was evaluated by Real-time quantitative polymerase chain reaction (RT-qPCR) combined with the analysis using GeNorm, NormFinder, and BestKeeper software. Comprehensive analysis of the results showed that ACTB was the most stable one, followed by EIF1 and GABARAP. Then, expression stability of the above three genes were validated, suggesting as suitable reference genes in sheep lung tissue, in additional 30 OPA-affected lung tissues and 10 healthy ovine lung tissues. Finally, our findings will be helpful for the subsequent study on the tumorigenic mechanism of OPA.

Exercise training preserves ischemic preconditioning in aged rat hearts by restoring the myocardial polyamine pool

BACKGROUND

Ischemic preconditioning (IPC) strongly protects against myocardial ischemia reperfusion (IR) injury. However, IPC protection is ineffective in aged hearts. Exercise training reduces the incidence of age-related cardiovascular disease and upregulates the ornithine decarboxylase (ODC)/polyamine pathway. The aim of this study was to investigate whether exercise can reestablish IPC protection in aged hearts and whether IPC protection is linked to restoration of the cardiac polyamine pool.

METHODS

Rats aging 3 or 18 months perform treadmill exercises with or without gradient respectively for 6 weeks. Isolated hearts and isolated cardiomyocytes were exposed to an IR and IPC protocol.

RESULTS

IPC induced an increase in myocardial polyamines by regulating ODC and spermidine/spermine acetyltransferase (SSAT) in young rat hearts, but IPC did not affect polyamine metabolism in aged hearts. Exercise training inhibited the loss of preconditioning protection and restored the polyamine pool by activating ODC and inhibiting SSAT in aged hearts. An ODC inhibitor, α-difluoromethylornithine, abolished the recovery of preconditioning protection mediated by exercise. Moreover, polyamines improved age-associated mitochondrial dysfunction in vitro.

CONCLUSION

Exercise appears to restore preconditioning protection in aged rat hearts, possibly due to an increase in intracellular polyamines and an improvement in mitochondrial function in response to a preconditioning stimulus.

Expression of transcripts related to intestinal ion and nutrient absorption in pregnant and lactating rats as determined by custom-designed cDNA microarray

In pregnancy and lactation, maternal adaptation for the enhancement of intestinal ion and nutrient absorption is of paramount importance for fetal development and lactogenesis. This nutrient hyperabsorption has been reported to result from upregulation of transporter gene expression, in part, under control of lactogenic hormone prolactin (PRL). Since a number of gene families are responsible for ion and nutrient transport in the rat small intestine, we herein developed a custom-designed cDNA microarray (CalGeneArray) to determine the transcriptome responses of duodenal epithelial cells during these reproductive periods, which was subsequently validated by quantitative real-time PCR. We thus designed 277 oligonucleotide probes to detect 113 transcripts related to ion/nutrient transport, bone/calcium metabolism, paracrine regulator, and cell metabolism. Pregnancy was found to upregulate the expressions of several duodenal transporters, e.g., Trpm6, Trpm7, Glut5, and Trpv6. Pregnant rats subjected to 7-day injection of bromocriptine, an inhibitor of PRL release, showed the increased levels of some other transcripts, e.g., insulin-2 and Cyp27b1, compared to untreated pregnant rats. Bromocriptine also increased the mRNA levels of insulin-2, glucose transporter-1 (Sglt1), and Cyp27b1, while decreasing those of Fgfr2c, Atp1b2, and Cldn19 in early lactation. During late lactation, the levels of eight studied transcripts (i.e., NaPi-IIb, Cyp27b1, Cldn18, Casr, Atp1b2, Xpnpep, Pept1, and Trpm7) were altered. In conclusion, the CalGeneArray was powerful to help reveal that pregnancy and lactation modulated the expression of genes related to duodenal nutrient transport and cell metabolism. Our findings supported the physiological significance of PRL in regulating nutrient absorption during pregnancy and lactation.