Dyschromatosis universalis hereditaria (DUH) is a pigmentary genodermatosis characterized by a mixture of hyperpigmented and hypopigmented macules distributed randomly over the body. No causative genes have been reported to date. In this study, we investigated a large five-generation Chinese family with DUH. After excluding the two known DUH loci, we performed genome-wide linkage analysis and identified a DUH locus on chromosome 2q33.3-q36.1 with a maximum LOD score of 3.49 with marker D2S2382. Exome sequencing identified a c.1067T>C (p.Leu356Pro) mutation in exon 3 of ABCB6 (ATP-binding cassette subfamily B, member 6) in the DUH family. Two additional missense mutations, c.508A>G (p.Ser170Gly) in exon 1 and c.1736G>A (p.Gly579Glu) in exon 12 of ABCB6, were found in two out of six patients by mutational screening using sporadic DUH patients. Immunohistologic examination in biopsy specimens showed that ABCB6 is expressed in the epidermis and had a diffuse cytoplasmic distribution. Examination of subcellular localization of wild-type ABCB6 in a B16 mouse melanoma cell line revealed that it is localized to the endosome-like compartment and dendrite tips, whereas disease-causing mutations of ABCB6 resulted in its retention in the Golgi apparatus. Our studies identified ABCB6 as the first pathogenic gene associated with DUH. These findings suggest that ABCB6 may be a physiological factor for skin pigmentation.
Background
As the extend of low‐protein diets in many countries including China, more researches of amino acid nutrition (AA) have been carried out. But the ideal AA pattern, especially the reasonable proportion of amino acids such as the desired methionine (Met): cystine (Cys) ratios are not yet clear.
Objectives
In this article, the experiments of low‐protein diet with varying ratios of Met:Cys (low ratio of 1:3, medium ratio of 1:1, and high ratio of 3:1) were conducted to investigate the effect on mice growth and reproductive performance.
Results
The result indicated that the lower Met:Cys ratio improves reproductive performance in male mice, but the growth performance were no change in all groups. Meanwhile, the abnormality rate of sperm increased as the ratio of methionine and cystine increased. Quantitative analysis showed that the low Met:Cys ratio has obviously decreased the expression of Bax protein and the concentrations of testosterone in male serum, but Prm2, Pgk2, Bcl‐2, Bak1, and AR gene were made no difference. Furthermore, different Met:Cys ratios have significant effects on the modulated methionine cycle by increasing the expressions of MAT2B, GNMT, and BHMT in low Met:Cys ratio. On the other hand, it was also found that there were increases in GSH‐Px enzyme activities and decreases in MDA levels in male serum.
Conclusions
Overall, the present study showed that a dietary lower Met:Cys ratio in a low‐protein diet had a positive influence on the reproductive performance of male animal through obviously improving sperm quality and antioxidant capacity, and inhibiting apoptosis. And the study provided new pieces of evidence to re‐evaluate the role of precise sulfur amino acid nutrition in a low‐protein diet.
The contamination of deoxynivalenol (DON) in feed is a global problem, which seriously threatens the productivity efficiency and welfare of farm animals and the food security of humans. Pig is the most sensitive species to DON, and is readily exposed to DON through its grain-enriched diet. The intestine serves as the first biological barrier to ingested mycotoxin, and is, therefore, the first target of DON. In the past decade, a growing amount of attention has been paid to plant-derived polyphenols as functional compounds against DON-induced oxidative stress and intestinal toxicity in pigs. In this review, we systematically updated the latest research progress in plant polyphenols detoxifying DON-induced intestinal toxicity in swine. We also discussed the potential underlying mechanism of action of polyphenols as Nrf2 activators in protecting against DON-induced enterotoxicity of swine. The output of this update points out an emerging research direction, as polyphenols have great potential to be developed as feed additives for swine to counteract DON-induced oxidative stress and intestinal toxicity.
Secretory immunoglobulin A (SIgA) plays an important role in gut acquired immunity and mucosal homeostasis. Breast milk is the irreplaceable nutritional source for mammals after birth. Current studies have shown the potential functional role of milk-derived small extracellular vesicles (sEVs) and their RNAs cargo in intestinal health and immune regulation. However, there is a lack of studies to demonstrate how milk-derived sEVs affect intestinal immunity in recipient. In this study, through in vivo experiments, we found that porcine milk small extracellular vesicles (PM-sEVs) promoted intestinal SIgA levels, and increased the expression levels of polymeric immunoglobulin receptor (pIgR) both in mice and piglet. We examined the mechanism of how PM-sEVs increased the expression level of pIgR in vitro by using a porcine small intestine epithelial cell line (IPEC-J2). Through bioinformatics analysis, dual-luciferase reporter assays, and overexpression or knockdown of the corresponding non-coding RNAs, we identified circ-XPO4 in PM-sEVs as a crucial circRNA, which leads to the expression of pIgR via the suppression of miR-221-5p in intestinal cells. Importantly, we also observed that oral administration of PM-sEVs increased the level of circ-XPO4 and decreased the level of miR-221-5p in small intestine of piglets, indicating that circRNAs in milk-derived sEVs act as sponge for miRNAs in recipients. This study, for the first time, reveals that PM-sEVs have a capacity to stimulate intestinal SIgA production by delivering circRNAs to receptors and sponging the recipient’s original miRNAs, and also provides valuable data for insight into the role and mechanism of animal milk sEVs in intestinal immunity.
MiR-143 play an important role in hepatocellular carcinoma and liver fibrosis via inhibiting hepatoma cell proliferation. DNA methyltransferase 3 alpha (DNMT3a), as a target of miR-143, regulates the development of primary organic solid tumors through DNA methylation mechanisms. However, the effect of miR-143 on DNA methylation profiles in liver is unclear. In this study, we used Whole-Genome Bisulfite Sequencing (WGBS) to detect the differentially methylated regions (DMRs), and investigated DMR-related genes and their enriched pathways by miR-143. We found that methylated cytosines increased 0.19% in the miR-143 knock-out (KO) liver fed with high-fat diet (HFD), compared with the wild type (WT). Furthermore, compared with the WT group, the CG methylation patterns of the KO group showed lower CG methylation levels in CG islands (CGIs), promoters and hypermethylation in CGI shores, 5′UTRs, exons, introns, 3′UTRs, and repeat regions. A total of 984 DMRs were identified between the WT and KO groups consisting of 559 hypermethylation and 425 hypomethylation DMRs. Furthermore, DMR-related genes were enriched in metabolism pathways such as carbon metabolism (serine hydroxymethyltransferase 2 (Shmt2), acyl-Coenzyme A dehydrogenase medium chain (Acadm)), arginine and proline metabolism (spermine synthase (Sms), proline dehydrogenase (Prodh2)) and purine metabolism (phosphoribosyl pyrophosphate synthetase 2 (Prps2)). In summary, we are the first to report the change in whole-genome methylation levels by miR-143-null through WGBS in mice liver, and provide an experimental basis for clinical diagnosis and treatment in liver diseases, indicating that miR-143 may be a potential therapeutic target and biomarker for liver damage-associated diseases and hepatocellular carcinoma.
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