microRNA regulation of skin pigmentation in fish.

MicroRNAs (miRNAs) are endogenous small non-coding RNAs that play crucial roles in numerous biological processes. However, the role of miRNAs in skin color determination in fish has not been completely determined. Here, we identified that 13 miRNAs are differentially expressed between red and white skin. The analysis of miRNA spatial and temporal expression patterns suggests that miR-429 is a potential regulator of skin pigmentation. miR-429 silencing results in an obvious change in skin pigmentation. Bioinformatics analysis and a luciferase reporter assay show that miR-429 directly regulates expression of Foxd3 by targeting its 3'-untranslated (3'-UTR) region. miR-429 silencing leads to a substantial increase in the expression of Foxd3 in vivo, thereby repressing the transcription of MITF and its downstream genes, such as TYR, TYRP1 or TYRP2. These findings would provide a novel insight into the determination of skin color in fish.

miRNA-directed regulation of VEGF in tilapia under hypoxia condition.

The Nile tilapia represents an excellent model for hypoxia tolerance. Vascular endothelial growth factor (VEGF) plays a key role in physiological blood vessel formation and pathological angiogenesis under hypoxia conditions. Tight regulation of VEGF level is necessary for hypoxia adaptation in tilapia. MicroRNAs (miRNAs) function as important regulators of gene expression at the post-transcriptional level, which are usually involved in stress responses. We reasoned that VEGF level could be regulated by miRNAs. Through bioinformatics analysis, we identified a putative miR-204 binding site in the VEGF mRNA. We found that hypoxia leads to a marked up-regulation in VEGF level, but a decrease in miR-204 level. miR-204 directly regulates VEGF expression by targeting its 3'-UTR, and inhibition of miR-204 substantially increases VEGF level in vivo. Moreover, we found that miR-204 loss of function could affect blood O2-carrying capacity, anaerobic metabolism, and antioxidant enzyme activity. Taken together, miR-204 is an endogenous regulator of VEGF expression, which participates in a regulatory circuit that allows rapid gene program transitions upon hypoxia stress.

MicroRNA repertoire for functional genome research in tilapia identified by deep sequencing.

The Nile tilapia (Oreochromis niloticus; Cichlidae) is an economically important species in aquaculture and occupies a prominent position in the aquaculture industry. MicroRNAs (miRNAs) are a class of noncoding RNAs that post-transcriptionally regulate gene expression involved in diverse biological and metabolic processes. To increase the repertoire of miRNAs characterized in tilapia, we used the Illumina/Solexa sequencing technology to sequence a small RNA library using pooled RNA sample isolated from the different developmental stages of tilapia. Bioinformatic analyses suggest that 197 conserved and 27 novel miRNAs are expressed in tilapia. Sequence alignments indicate that all tested miRNAs and miRNAs* are highly conserved across many species. In addition, we characterized the tissue expression patterns of five miRNAs using real-time quantitative PCR. We found that miR-1/206, miR-7/9, and miR-122 is abundantly expressed in muscle, brain, and liver, respectively, implying a potential role in the regulation of tissue differentiation or the maintenance of tissue identity. Overall, our results expand the number of tilapia miRNAs, and the discovery of miRNAs in tilapia genome contributes to a better understanding the role of miRNAs in regulating diverse biological processes.

Effect of Physical Activity on the Association Between Diet and Constipation: Evidence From the National Health and Nutrition Examination Survey 2007-2010.

Background/Aims: Previous studies have shown that diet and physical activity can influence constipation. However, the combined effect of diet and physical activity on constipation remains unclear. Methods: Constipation was defined based on stool consistency and frequency, while overall diet quality was assessed using Healthy Eating Index (HEI)-2015 scores. Participants were categorized into low (metabolic equivalent [MET]-min/wk < 500) and high physical activity groups (MET-min/wk ≥ 500). The association between diet and constipation across physical activity groups was analyzed using survey logistic regression and restricted cubic splines. Results: Higher HEI-2015 scores were associated with reduced constipation risk in the high physical activity group when constipation was defined by stool consistency (odds ratio [OR], 0.98; 95% confidence interval [CI], 0.97-0.99). However, in the low physical activity group, increased HEI-2015 scores did not significantly affect constipation risk (OR, 1.01; 95% CI, 0.97-1.05). Similar results were found when constipation was defined based on stool frequency. In the high physical activity group, increased HEI-2015 scores were significantly associated with a reduced constipation risk (OR, 0.96; 95% CI, 0.94-0.98). Conversely, in the low physical activity group, increased HEI-2015 scores did not affect the risk of constipation (OR, 0.96; 95% CI, 0.90-1.03). Conclusions: Our findings suggest that a higher HEI-2015 score is negatively associated with constipation among individuals with high physical activity levels but not among those with low physical activity levels. This association was consistent when different definitions of constipation were used. These results highlight the importance of combining healthy diet with regular physical activity to alleviate constipation.

miR-203b: a novel regulator of MyoD expression in tilapia skeletal muscle.

MyoD is one of the helix-loop-helix proteins regulating muscle-specific gene expression in tilapia. Tight regulation of the MyoD protein level is necessary for the precise regulation of skeletal muscle development. MicroRNAs (miRNAs) are a class of regulatory RNAs that post-transcriptionally regulate gene expression. An increasing amount of evidence has suggested that miRNAs play an important role in regulating skeletal muscle development. We reasoned that MyoD expression may be regulated by miRNAs. Predictions from bioinformatics have identified a putative miR-203b target site in the 3'-UTR of the MyoD gene. Interestingly, miR-203b expression is negatively correlated with MyoD expression, whereas miR-203b suppression leads to a significant increase in MyoD expression, thereby activating MyoD downstream genes. A 3'-UTR luciferase reporter assay further verifies the direct interaction between miR-203b and MyoD. Taken together, our results reveal a novel molecular mechanism in which miRNA participates in transcriptional circuits that regulate gene expression in tilapia skeletal muscle.

miR-206 regulates the growth of the teleost tilapia (Oreochromis niloticus) through the modulation of IGF-1 gene expression.

MicroRNAs (miRNAs) are ~22-nucleotide noncoding RNAs that play a crucial role in regulating muscle development. Our previous study shows that miR-206 is specifically expressed in tilapia skeletal muscle, and exhibits a dynamic expression pattern at different developmental stages. Here, we reveal that miR-206 emerges as a crucial regulator of tilapia growth. miR-206 loss of function leads to the acceleration of tilapia growth. IGF-1 is identified as the target gene of miR-206. miR-206 directly changes IGF-1 expression by targeting its 3' UTR, and inhibition of miR-206 substantially increases the IGF-1 mRNA level in vivo. Thus, miR-206 could be developed as a molecular marker to assist fish breeding.

Characterization of four novel H5N6 avian influenza viruses with the internal genes from H5N1 and H9N2 viruses and experimental challenge of chickens vaccinated with current commercially available H5 vaccines.

Since 2014, highly pathogenic avian influenza H5N6 viruses have been responsible for outbreaks in poultry. In this study, four H5N6 virus strains were isolated from faecal samples of sick white ducks and dead chickens in Shandong in 2019. These H5N6 viruses were triple-reassortant viruses that have not been previously characterized. Their HA genes were derived from the H5 viruses and were closely related to the vaccine strain Re-11. Their NA genes all fell into the N6-like lineage and the internal gene were derived from H5N1 and H9N2 viruses. They all showed high pathogenicity in mice and caused lethal infection with high rates of transmission in chickens. Moreover, the SPF chickens inoculated with the currently used H5 (Re-11 and Re-12 strains)/H7 (H7-Re-2 strain) trivalent inactivated vaccines in China were completely protected from these four H5N6 viruses. Our study indicated the necessity of continued surveillance for H5 influenza A viruses and the importance of timely update of vaccine strains in poultry industry.

[Effects of acupuncture and "Tongxinluo" capsule on plasma lysophosphatidic acid level in patients with acute cerebral infarction].

OBJECTIVE: To observe the effect of acupuncture of Neiguan (PC 6), Sanyinjiao (SP 6), etc. on plasma lysophosphatidic acid (LPA) level in patients with acute cerebral infarction (ACI) so as to study its mechanism underlying improvement of ACI. METHODS: A total of 160 patients with ACI were randomly divided into four groups: medication (Aspirin and Panax Notoginseng Saponins for improving blood circulation), acupuncture, Tongxinluo, and acupuncture+ Tongxinluo groups, with 40 cases being in each group. Plasma LPA content was measured using biochemical method, and the therapeutic effects of the 4 groups were assessed by neurologic deficit score which were evaluated using the modified standards of the 4Th Session of Chinese National Cerebrovascular Conference issued in 1995. RESULTS: Following the treatment, plasma LPA levels and neurological deficit scores were significantly decreased in the medication, acupuncture, Tongxinluo and acupuncture+ Tongxinluo groups in com- parison with pre-treatment in each group (P<0.01), and LPA level and neurological deficit score of the acupuncture + Tongxinluo group were significantly lower than those of the other three groups (P<0. 01). Of the four 40 cases in the medication, acupuncture, Tongxinluo and acupuncture+Tongxinluo groups, 6, 7, 7 and 12 patients were basically cured, 9, 8, 9 and 18 experienced marked improvement in their symptoms, 14, 16, 15 and 6 were improved, 6, 5, 4 and 2 were invalid, 5, 4, 5 and 2 got worsened, with the effective rates(basically cured+ improvement) being 37.5%, 37.5%, 40.0% and 75.0%, respectively. The therapeutic effect of the acupuncture+Tongxinluo group was significantly superior to those of the other three groups (P<0. 01). CONCLUSION: Acupuncture can accelerate the recovery of neurological function and ameliorate clinical symptoms in ACI patients, which may be related to its effect in lowering plasma PLA. The therapeutic effect of acupuncture + Tongxinluo is relatively better than simple acupuncture and simple medication.

Strategies for hypoxia adaptation in fish species: a review.

Aquatic environments exhibit wide temporal and spatial variations in oxygen levels compared to terrestrial environments. Fish are an excellent model for elucidating the underlying mechanisms of hypoxia adaptation. Over the past decade, several hypoxia-related proteins have been reported to act in concert to convey oxygen change information to downstream signaling effectors. Some signaling pathways, such as redox status, AMPK, MAPK and IGF/PI3K/Akt, are known to play a central role in hypoxia adaptation. These networks regulate oxygen-sensitive transcription factors which, in turn, affect the expression of hypoxia adaptation-related genes. This review summarizes current insights into hypoxia adaptation-related proteins and signaling pathways in fish.

AluYb8 insertion in the MUTYH gene and risk of early-onset breast and gastric cancers in the Chinese population.

BACKGROUND: A common polymorphism of the AluYb8 insertion in the MUTYH gene (AluYb8MUTYH), which led to the increase of oxidative DNA damage and acceleration of chronic diseases, was previously detected. Considering the relationship between carcinogenesis and oxidative stress, an investigation was held on whether the common variant of the MUTYH gene increases the risk for gastric and breast cancers. METHODS: The AluYb8MUTYH allele frequencies of 545 breast cancer patients and 762 gastric cancer patients were analyzed and compared with that of the healthy control group using the Chi-square test. The binary logistic regression model was used to examine the association between the polymorphism genotypes and cancer risk. Genomic DNA specimens from the investigated population were tested by polymerase chain reaction in agarose gel electrophoresis. According to the insertion absence or presence of the variant segment, the patterns for the AluYb8MUTYH genotypes were classified as a homozygous of absence/absence (A/A) and presence/presence (P/P) or a heterozygous of absence/presence (A/P). RESULTS: The variant allele frequency (insertion present, P) was inclined to be enhanced in breast cancer patients as compared with the normal female controls (46.8% versus 43.3%), and also, in gastric cancer patients, as compared with the general normal controls (45.1% versus 43.9%). However, a significantly different P allele frequency was only detected between the early-onset breast cancer patients (<55 years old) and their counterpart female controls (46.6% versus 40.9%, p=0.042; OR=1.26, 95% CI, 1.01-1.56), as well as between the early-onset gastric cancer patients and their respective controls (49.2% versus 41.3%, p=0.042; OR, 1.37; 95% CI, 1.02-1.85). Comparisons on the genotypes of AluYb8MUTYH show that this variation of MUTYH has also a significantly higher prevalence in the early-onset cancer patients, either in breast or gastric cancer patients, than that in their counterpart controls. CONCLUSIONS: The AluYb8MUTYH allele frequency can be associated with the early-onset breast and gastric cancer in the Chinese population. Probably, there is importance in screening the carriers with the susceptibility alleles to evaluate their risk of breast and gastric cancer for further research.

The hOGG1 gene 5'-UTR variant c.-53G>C contributes to the risk of gastric cancer but not colorectal cancer in the Chinese population: the functional variation of hOGG1 for gastric cancer risk.

PURPOSE: The incidence and mortality of gastric and colorectal cancers are among the highest malignant tumors in China. The aim of this study is to investigate whether variations of the human oxoguanine glycosylase 1 (hOGG1) gene are related to the risk of gastric and colorectal cancers in the Chinese population. METHODS: There were 622 gastric cancer patients, 383 colorectal cancer patients, and 932 healthy controls recruited to screen for variations in the 5'untranslated region (UTR) and to screen for the missense mutation (p.Ser326Cys) in exon7 of the hOGG1 gene using high-resolution melting curve analysis (HRM) and subsequent sequencing. The promoter luciferase activity assay was applied to assess the potential influence of the detected variants on gene function. RESULTS: Four variations, c.-53G>C, c.-45G>A, c.-23A>G, and c.-18G>T, were detected in the 5'-UTR of the hOGG1 gene. The case-control study indicated that the c.-53G/C heterozygous genotype was markedly associated with gastric cancer (P = 0.008, OR = 2.304, 95% CI, 1.258-4.221), but not with colorectal cancer. The clinicopathological association analysis showed that the variant of c.-53G>C in the hOGG1 gene was prevalent in low-differentiation patients (P = 0.012, OR = 3.174, 95% CI: 1.352-7.448). This variant decreased the gene promoter activity by approximately 17.8% (P = 0.041) and exhibited a synergistic effect with the missense mutation p.Ser326Cys of hOGG1 by enhancing susceptibility to gastric cancers. CONCLUSIONS: The variant c.-53G>C in the 5'-UTR of the hOGG1 gene is a risk factor for gastric cancer and is potentially associated with low-differentiation degree, but not with colorectal cancer, in the Chinese population.