Metformin Attenuates Neutrophil Recruitment through the H3K18 Lactylation/Reactive Oxygen Species Pathway in Zebrafish.

Beyond its well-established role in diabetes management, metformin has gained attention as a promising therapeutic for inflammation-related diseases, largely due to its antioxidant capabilities. However, the mechanistic underpinnings of this effect remain elusive. Using in vivo zebrafish models of inflammation, we explored the impact of metformin on neutrophil recruitment and the underlying mechanisms involved. Our data indicate that metformin reduces histone (H3K18) lactylation, leading to the decreased production of reactive oxygen species (ROS) and a muted neutrophil response to both caudal fin injury and otic vesicle inflammation. To investigate the precise mechanisms through which metformin modulates neutrophil migration via ROS and H3K18 lactylation, we meticulously established the correlation between metformin-induced suppression of H3K18 lactylation and ROS levels. Through supplementary experiments involving the restoration of lactate and ROS, our findings demonstrated that elevated levels of both lactate and ROS significantly promoted the inflammatory response in zebrafish. Collectively, our study illuminates previously unexplored avenues of metformin's antioxidant and anti-inflammatory actions through the downregulation of H3K18 lactylation and ROS production, highlighting the crucial role of epigenetic regulation in inflammation and pointing to metformin's potential in treating inflammation-associated conditions.

Circadian clock1a coordinates neutrophil recruitment via nfe212a/duox-reactive oxygen species pathway in zebrafish.

Neutrophil recruitment to inflammatory sites appears to be an evolutionarily conserved strategy to fight against exogenous insults. However, the rhythmic characteristics and underlying mechanisms of neutrophil migration on a 24-h timescale are largely unknown. Using the advantage of in vivo imaging of zebrafish, this study explored how the circadian gene clock1a dynamically regulates the rhythmic recruitment of neutrophils to inflammatory challenges. We generated a clock1a mutant and found that neutrophil migration is significantly increased in caudal fin injury and lipopolysaccharide (LPS) injection. Transcriptome sequencing, chromatin immunoprecipitation (ChIP), and dual-luciferase reporting experiments suggest that the clock1a gene regulates neutrophil migration by coordinating the rhythmic expression of nfe212a and duox genes to control the reactive oxygen species (ROS) level. This study ultimately provides a visual model to expand the understanding of the rhythmic mechanisms of neutrophil recruitment on a circadian timescale in a diurnal organism from the perspective of ROS.

Fluoxetine modifies circadian rhythm by reducing melatonin content in zebrafish.

Fluoxetine (FLX), a selective serotonin reuptake inhibitor (SSRI), increases the serotonin levels in the brain to treat depression. Antidepressants have been demonstrated to modulate circadian rhythm, but the underlying mechanisms by which antidepressants regulate circadian rhythm require more research. This study aimed to investigate the role of FLX on circadian rhythm by analyzing the movement behavior and internal circadian oscillations in zebrafish. The results showed that the expression of clock genes clock1a and bmal1b was significantly down-regulated, and the amplitude reduction and phase shift were observed after FLX treatment. Furthermore, FLX exposure inhibited the expression of aanat2, which led to a decrease in nocturnal melatonin secretion. aanat2-/- larvae showed disrupted circadian rhythm. These findings may help reveal the effect of FLX exposure on the circadian rhythm and locomotor activity. It may provide theoretical data for the clinical application of FLX.

Expression and genomic imprinting of the porcine Rasgrf1 gene.

Imprinted genes play important roles in mammalian growth, development and behavior. The Rasgrf1 (Ras protein-specific guanine nucleotide exchange factor 1) gene has been identified as an imprinted gene in mouse and rat. In the present study, we detected its sequence, imprinting status and expression pattern in the domestic pigs. A 228 bp partial sequence located in exon 14 and a 193 bp partial sequence located in exon 1 of the Rasgrf1 gene in domestic pigs were obtained. A G/A transition, was identified in Rasgrf1 exon 14, and then, the reciprocal Berkshire × Wannan black F1 hybrid model and the RT-PCR-RFLP method were used to detect the imprinting status of porcine Rasgrf1 gene at the developmental stage of 1-day-old. The expression profile results indicated that the porcine Rasgrf1 mRNA was highly expressed in brain, pituitary and pancreas, followed by kidney, stomach, lung, testis, small intestine, ovary, spleen and liver, and at low levels of expression in longissimus dorsi, heart, and backfat. The expression levels of Rasgrf1 gene in brain, pituitary and pancreas tissues were significantly different between the two reciprocal F1 hybrids. Imprinting analysis showed that porcine Rasgrf1 gene was maternally expressed in the liver, small intestine, paternally expressed in the lung, but biallelically expressed in brain, heart, spleen, kidney, stomach, pancreas, backfat, testis, ovary, longissimus dorsi and pituitary tissues.

Characterization and differential expression of microRNAs in the ovaries of pregnant and non-pregnant goats (Capra hircus).

BACKGROUND: Ovarian follicular development and hormone secretion are complex and coordinated biological processes which will usually be altered during pregnancy. Ovarian function is tightly regulated by a multitude of genes, and also by some specific miRNAs. It is necessary to identify the differentially expressed miRNAs in the ovaries of pregnant and non-pregnant mammals, in order to further understand the role of miRNA-mediated post-transcriptional regulation in mammalian reproduction. Here, we performed a comprehensive search for hircine miRNAs using two small RNA sequencing libraries prepared from the ovaries of pregnant and non-pregnant goats. RESULTS: 617 conserved and 7 putative novel miRNAs were identified in the hircine ovaries. A total of 471 conserved miRNAs (76.34%) were co-expressed in both pregnant and non-pregnant libraries, and 90 pregnancy-specific and 56 non-pregnancy-specific conserved miRNAs were identified. Additionally, 407 unique miRNAs (65.96%) were significantly differentially expressed in the pregnant and non-pregnant libraries, of which 294 were upregulated and 113 were downregulated in the pregnant library compared to the non-pregnant library. Further analysis showed that miR-143 was predicted to bind to the target sequences of Frizzled-6 and -3 receptor genes in the Wnt/beta-catenin signaling pathway, and let-7b may target the Activin receptor I and Smad 2/3 genes in the TGF-beta signaling pathway. The expression level of 5 randomly selected miRNAs were analyzed by quantitative real-time PCR (q-PCR), and the results demonstrated that the expression patterns were consistent with the Solexa sequencing results. CONCLUSIONS: The identification and characterization of differentially expressed miRNAs in the ovaries of pregnant and non-pregnant goats provides important information on the role of miRNA in the regulation of the ovarian development and function. This data will be helpful to facilitate studies on the regulation of miRNAs during mammalian reproduction.

[Changes in the mRNA expression of adiponectin, adiponectin receptors, and leptin in adipose tissue of Wannanhua pigs at different stages of development].

OBJECTIVE: To explore the changes in the mRNA expression of adiponectin (Adp), adiponectin receptors(AdpR), and leptin in different adipose tissues of Wannanhua pigs at different stages of development, and their sexual dimorphism. METHODS: Five Wannanhua boars and five Wannanhua gilts were sampled at birth, 30, 45, 90, and 180 days of age respectively. The delta delta Ct relative quantification real-time PCR was used to detect the transcription levels of Adp, AdpR1, AdpR2, and leptin mRNAs in subcutaneous (SC) and perirenal (PR) adipose tissues, and beta-actin were used as internal standards. RESULTS: The expression level of Adp, AdpR1, AdpR2, and leptin mRNA in SC and PR adipose tissue were changed with age significantly (P < 0.01). In general, Adp mRNA expression in SC adipose tissue was significantly lower than that in PR adipose tissue (P < 0.05), while AdpR1, AdpR2, and leptin mRNA expression in SC adipose tissue were significantly higher than those in PR adipose tissue (P < 0.05 or P < 0.01). Although the sexual dimorphism were found in apart genes or apart days of age, Adp, AdpR1, AdpR2, and leptin mRNA expression both in SC adipose tissue and PR adipose tissue had no significant differences between Wannanhua gilts and boars in general. Significant positive correlation was found between Adp and AdpR1, AdpR2 (P < 0.05 or P < 0.01), and significant negative correlation was found between Adp and leptin (P < 0.05) in SC adipose tissue and PR adipose tissue respectively (P < 0.05). CONCLUSION: The expression of Adp, AdpR1, AdpR2, and leptin mRNA in adipose tissue of Wannanhua pigs followed specific developmental patterns and tissue specificity. Adp correlated with its receptors.

Complex embryos displaying bilaterian characters from Precambrian Doushantuo phosphate deposits, Weng'an, Guizhou, China.

Three-dimensionally preserved embryos from the Precambrian Ediacaran Doushantuo Formation, Weng'an, Guizhou, southern China, have attracted great attention as the oldest fossil evidence yet found for multicellular animal life on Earth. Many embryos are early cleavage embryos and most of them yield a limited phylogenetic signal. Here we report the discovery of two Doushantuo embryos that are three-dimensionally preserved and complex. Imaging techniques using propagation phase-contrast based synchrotron radiation microtomography (PPC-SR-microCT) reveal that the organization of cells demonstrates several bilaterian features, including the formation of anterior-posterior, dorso-ventral, and right-left polarities, and cell differentiation. Unexpectedly, our observations show a noticeable difference in organization patterns between the embryos, suggesting that they represent two distinct taxa. These embryos provide further evidence for the presence of bilaterian animals in the Doushantuo biota. Furthermore, these bilaterians had already diverged into distantly related groups at least 40 million years before the Cambrian radiation, indicating that the last common ancestor of the bilaterians lived much earlier than is usually thought.

[Methodology of QTL's linkage analysis for discrete traits controlled by polygenes].

Many characters of biological interest and economical importance that are not inherited in a simple Mendelian fashion vary in a discrete form. These traits are called complex discrete traits. A complex discrete trait is presumably controlled by several genes, and characteristic of the trait is modified by environmental effects. Although methods of mapping QTL for continuous quantitative characters have been well developed, such methods for discrete characters are not available yet. So many non-linear methods were developed under the framework of the generalized linear model. In this paper, we reviewed the recent progress and improvement of the methods for QTL mapping in this field.

A non-transformation method for identifying differentially expressed genes from cDNA microarrays.

cDNA microarray data are subject to many sources of variation that have to be removed before statistical tests can be applied for identifying genes that are expressed differentially. Background correction, log-ratio transformation, and normalization, referred as the log-ratio approach, have been widely used for this purpose. However, there are some problems associated with this procedure. In this study, we proposed an alternative approach that obviates the log-ratio transformation step and goes directly to normalization after background correction. The method can estimate the "noise" effect by utilizing the information more effectively. Simulation studies were carried out to compare the feasibility and efficiency of this approach for detecting the specifically and differentially expressed genes under various conditions with the log-ratio approach. The results showed that our approach worked well and was more robust and powerful than the log-ratio approach.

Methodology of mapping quantitative trait loci for ordinal traits of disease resistance in livestock.

Methodology of QTL mapping for ordinal traits of disease resistance based on the framework of a generalized linear model (GLM) was presented. The location and effect parameters of putative QTL were estimated using maximum likelihood method. The efficiency and power were compared with the linear model (LM). The factors influencing QTL detection efficiency (e.g. QTL effect and heritability) were simulated in our study too. Daughter design with multiple families was applied,and the number of segregating population was 500. Results showed that the threshold model has a certain advantage in location estimation and power of QTL mapping, and has efficiency and accuracy for ordinal traits. In addition,the accuracy of QTL mapping depends on the effect of putative quantitative trait loci and the value of heritability. With the increase of QTL effect and heritability, the accuracy of QTL mapping improves slightly.

[Methodology of mapping quantitative trait loci for discrete traits using maximum likelihood].

The maximum likelihood method was used to compare the efficiency of interval mapping with either the threshold model or the linear model. The irfluencing factors of quantitative trait loci (QTL) detection efficiency (e.g. QTL effect, heritability and incidence of categories) were simulated in our study. Daughter design with multiple families was applied, and the number of segregating population was 500. The results showed that the threshold model was superior in terms of parameter estimation. It was a more efficient and accurate model of QTL mapping for discrete traits. In addition, the accuracy of QTL mapping depended on the effect of the putative QTL, the value of heritability and incidence directly. With an increase of QTL effect, heritability and incidence of categories, the accuracy of QTL mapping improved correspondingly.