Ankrd1 inhibits the FAK/Rho-GTPase/F-actin pathway by downregulating ITGA6 transcriptional to regulate myoblast functions.

Skeletal muscle constitutes the largest percentage of tissue in the animal body and plays a pivotal role in the development of normal life activities in the organism. However, the regulation mechanism of skeletal muscle growth and development remains largely unclear. This study investigated the effects of Ankrd1 on the proliferation and differentiation of C2C12 myoblasts. Here, we identified Ankrd1 as a potential regulator of muscle cell development, and found that Ankrd1 knockdown resulted in the proliferation ability decrease but the differentiation level increase of C2C12 cells. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyzes as well as RNA-seq results showed that Ankrd1 knockdown activated focal adhesion kinase (FAK)/F-actin signal pathway with most genes significantly enriched in this pathway upregulated. The integrin subunit Itga6 promoter activity is increased when Ankrd1 knockdown, as demonstrated by a dual-luciferase reporter assay. This study revealed the molecular mechanism by which Ankrd1 knockdown enhanced FAK phosphorylation activity through the alteration of integrin subunit levels, thus activating FAK/Rho-GTPase/F-actin signal pathway, eventually promoting myoblast differentiation. Our data suggested that Ankrd1 might serve as a potential regulator of muscle cell development. Our findings provide new insights into skeletal muscle growth and development and valuable references for further study of human muscle-related diseases.

Proteomic profiles and the function of RBP4 in endometrium during embryo implantation phases in pigs.

BACKGROUND: Endometrial receptivity plays a vital role in the success of embryo implantation. However, the temporal proteomic profile of porcine endometrium during embryo implantation is still unclear. RESULTS: In this study, the abundance of proteins in endometrium on days 9, 10, 11, 12, 13, 14, 15 and 18 of pregnancy (D9, 10, 11, 12, 13, 14, 15 and 18) was profiled via iTRAQ technology. The results showed that 25, 55, 103, 91, 100, 120, 149 proteins were up-regulated, and 24, 70, 169, 159, 164, 161, 198 proteins were down-regulated in porcine endometrium on D10, 11, 12, 13, 14, 15 and 18 compared with that on D9, respectively. Among these differentially abundance proteins (DAPs), Multiple Reaction Monitoring (MRM) results indicated that S100A9, S100A12, HRG and IFI6 were differentially abundance in endometrial during embryo implantation period. Bioinformatics analysis showed that the proteins differentially expressed in the 7 comparisons were involved in important processes and pathways related to immunization, endometrial remodeling, which have a vital effect on embryonic implantation. CONCLUSION: Our results reveal that retinol binding protein 4 (RBP4) could regulate the cell proliferation, migration and apoptosis of endometrial epithelial cells and endometrial stromal cells to affect embryo implantation. This research also provides resources for studies of proteins in endometrium during early pregnancy.

Ssc-miR-21-5p regulates endometrial epithelial cell proliferation, apoptosis and migration via the PDCD4/AKT pathway.

Endometrial receptivity plays a vital role in successful embryo implantation in pigs. MicroRNAs (miRNAs), known as regulators of gene expression, have been implicated in the regulation of embryo implantation. However, the role of miRNAs in endometrial receptivity during the pre-implantation period remains elusive. In this study, we report that the expression level of Sus scrofa (ssc)-miR-21-5p in porcine endometrium tissues was significantly increased from day 9 to day 12 of pregnancy. Knockdown of ssc-miR-21-5p inhibited proliferation and migration of endometrial epithelial cells (EECs), and induced their apoptosis. We verified that programmed cell death 4 (PDCD4) was a target gene of ssc-miR-21-5p. Inhibition of PDCD4 rescued the effect of ssc-miR-21-5p repression on EECs. Our results also revealed that knockdown of ssc-miR-21-5p impeded the phosphorylation of AKT (herein referring to AKT1) by targeting PDCD4, which further upregulated the expression of Bax, and downregulated the levels of Bcl2 and Mmp9. Furthermore, loss of function of Mus musculus (mmu)-miR-21-5p in vivo resulted in a decreased number of implanted mouse embryos. Taken together, knockdown of ssc-miR-21-5p hampers endometrial receptivity by modulating the PDCD4/AKT pathway.

Extracellular vesicles derived from endometrial epithelial cells deliver exogenous miR-92b-3p to affect the function of embryonic trophoblast cells via targeting TSC1 and DKK3.

BACKGROUND: Extracellular vesicles (EVs) could mediate embryo-maternal communication to affect embryo implantation by delivering biology information, including microRNA (miRNA), protein, lipid. Our previous research shows that miR-92b-3p was differentially expressed in EVs of uterine flushing fluids during the embryo implantation period. However, the role of miR-92b-3p from EVs in embryo implantation remains elusive. MATERIALS AND METHODS: EVs were isolated from porcine endometrial epithelial cells (EECs) by ultracentrifugation. MiR-92b-3p mimics and EVs were used to regulate the expression of miR-92b-3p in porcine trophoblast cells (PTr2 cells). Cell proliferation, migration and adhesion analyses were used to observe the phenotype. RT-qPCR, western blot and dual-luciferase reporter assay were used to assess the targets of miR-92b-3p. RESULTS: In this study, EVs derived from porcine EECs were identified and could be taken up by PTr2 cells. We found that the EVs derived from EECs transfected with miR-92b-3p mimic (EVs-miR-92b-3p) significantly promoted the proliferation, migration and adhesion of PTr2 cells. We verified that Tuberous sclerosis complex subunit (TSC1) and Dickkopf 3 (DKK3) were the target genes of miR-92b-3p. Moreover, our study showed that miR-92b-3p plays a vital role in PTr2 cells via targeting TSC1 and DKK3. Furthermore, the 3'UTR vectors of TSC1 and DKK3 can rescue the effect of miR-92b-3p on PTr2 cells. CONCLUSIONS: Taken together, this study reveals a novel mechanism that EVs derived from porcine EECs treated with miR-92b-3p crosstalk with trophoblasts by targeting TSC1 and DKK3, leading to an enhanced ability for implantation.

MiR-543 regulates myoblast proliferation and differentiation of C2C12 cells by targeting KLF6.

MicroRNA-543 (miR-543) has been found to play a suppressive role in various human cancers in many studies, whereas the specific functions of miR-543 in muscle development remain poorly understood. Here, we found that the expression of miR-543 was high in skeletal muscle and increased during the differentiation of C2C12 cells. Overexpression of miR-543 repressed C2C12 cell proliferation and promoted differentiation, while knockdown of miR-543 expression produced the opposite results. During myogenesis, we predicted and verified that Krüppel-like factor 6 (KLF6), a suppressor of multiple tumor cells, was a target gene of miR-543. Then, miR-543 was found to specifically target KLF6 and repress its expression. Besides this, knockdown of KLF6 promoted the differentiation but inhibited the proliferation of C2C12 cells. Si-KLF6 can rescue the influence of miR-543 inhibitor on C2C12 cell differentiation. Our results indicate a new regulatory mechanism of miR-543 on KLF6 expression and suggest the possibility of using the miR-543/KLF6 pathway as a potential target for studying myogenesis.

mRNA/lncRNA expression patterns and the function of fibrinogen-like protein 2 in Meishan pig endometrium during the preimplantation phases.

Embryonic implantation involves a complex and well-coordinated interaction between the developing conceptus and maternal uterus, and the preimplantation period has a major impact on litter size in pigs. The present study aimed to investigate the vital messenger RNAs (mRNAs) and long noncoding RNAs (lncRNAs) that regulate preimplantation in Meishan pigs. The enriched Gene Ontology terms were all related to "binding." Furthermore, "ECM-receptor interaction" was predicted as an important pathway that regulated the success of implantation. We speculated that the differentially expressed mRNAs S100A9, ANXA8, MUC16, and FGL2 and the differentially expressed lncRNAs TCONS_11206566, TCONS_09904861, and TCONS_1252933 may play vital roles in the process of implantation. Furthermore, this study verified that FGL2 was highly expressed on Day 12 of pregnancy, and we also investigated the function of FGL2 during preimplantation in vivo. In conclusion, this study provides useful information for further analyses of the molecular mechanisms of implantation in Chinese domestic pigs.

Annexin A8 (ANXA8) regulates proliferation of porcine endometrial cells via Akt signalling pathway.

Annexin A8 (ANXA8) gene, a member of the annexin family, encodes an anticoagulant protein involved in blood coagulation cascade and acts as an indirect inhibitor of the thromboplastin-specific complex. However, little is known about the function of ANXA8 in porcine endometrial cells so far. Here, ANXA8 mRNA was found to be abundant in porcine endometrium on days 11-13 of pregnancy. Real-time RT-PCR analysis indicated that the mRNA expression of the leukaemia inhibitory factor (LIF) and the epidermal growth factor (EGF) was upregulated by ANXA8 in porcine endometrial cells. Immunofluorescence technology and cell cycle analysis revealed that ANXA8 promoted the proliferation of endometrial cells, as evidenced by the abundant proliferating cell nuclear antigen (PCNA) expression and an increase in the S phase. Western blot analysis results indicated that ANXA8 activated the phosphorylation of the target protein kinase B (Akt) protein. Immunofluorescence technology results showed that the PCNA protein had no significant change in porcine endometrial cells with both ANXA8 overexpression and the addition of Akt inhibitor. Furthermore, the number of implantation sites was significantly reduced by injection of mus-siRNA-ANXA8 into the uterine horn of mice. Collectively, these results suggest that ANXA8 promotes the proliferation of endometrial cells through the Akt signalling pathway.

Comparative transcriptomic analysis of skeletal muscle tissue during prenatal stages in Tongcheng and Yorkshire pig using RNA-seq.

Myogenesis is accompanied by a number of changes in gene expression in mammals, and the transcriptional events that underlie these processes have not been yet fully elucidated. In this study, RNA-seq was used to comprehensively compare the transcription profiles of skeletal muscle between Tongcheng (TC) and Yorkshire (YK) pigs at 40, 55, 63, 70, and 90 days of gestation. One thousand three hundred seventeen and 691 differentially expressed genes (DEGs) were detected in TC and YK, respectively, among which 321 DEGs were shown to be common in TC and YK. STEM (Time-series Expression Miner) analysis revealed different gene expression profiles between the two breeds. One thousand six hundred seventy-seven genes showed significant differential expression between TC and YK at the identical stages, while three genes were found to be common in all comparisons. A total of 3185 new putative transcripts were also predicted. Several gene expression profiles were further validated by qRT-PCR. Fifty-five dpc (days post coitum) was suggested to be the key stage to contribute developmental differences between TC and YK. PTEN, EP300, ENSSSCG00000004979 (Myosin 9A), CDK14, IRS1, PPP1CC, and some ribosomal proteins were suggested to be the key candidate genes for elucidating the developmental differences between the two breeds. In conclusion, we constructed comprehensive high-resolution gene expression maps of these two pig breeds, which not only provides an in-depth understanding of the dynamics of transcriptional regulation during myogenesis in this study, but also would facilitate the elucidation of molecular mechanisms underlying myogenesis in the future studies.

Identification of non-coding and coding RNAs in porcine endometrium.

One of the most critical periods of embryonic loss in pig is day 12 of pregnancy, when implantation begins. Here, we analyzed the gene expression on day 12 of pregnancy and non-pregnancy in the porcine endometrium using RNA sequencing (RNA-seq). 237 mRNAs, 34 lncRNAs and 1 miRNA were significantly differentially expressed between the two groups. Further functional analyses were conducted to identify these differentially expressed transcripts. The results demonstrated that they participate in various biological processes, such as cell adhesion, binding, nucleic and metabolic processes. In addition, our results showed that the differentially expressed genes (IL1R, FGF9, DUPS10, DUPS4, CD14 and MAP4K4) in MAPK pathway, and lncRNAs of XLOC_2604764 and XLOC_2604756 may play a vital role in regulating embryo implantation. Besides, we investigated the lncRNA-ssc-miR-132-mRNA interactions, aiming to explain the regulatory networks of coding and non-coding genes that contributes to the establishment of the maternal pregnancy.

Transcription Factor Sp1 Promotes the Expression of Porcine ROCK1 Gene.

Rho-associated, coiled-coil containing protein kinase 1 (ROCK1) gene plays a crucial role in maintaining genomic stability, tumorigenesis and myogenesis. However, little is known about the regulatory elements governing the transcription of porcine ROCK1 gene. In the current study, the transcription start site (TSS) was identified by 5'-RACE, and was found to differ from the predicted one. The region in ROCK1 promoter which is critical for promoter activity was investigated via progressive deletions. Site-directed mutagenesis indicated that the region from -604 to -554 bp contains responsive elements for Sp1. Subsequent experiments showed that ROCK1 promoter activity is enhanced by Sp1 in a dose-dependent manner, whereas treatment with specific siRNA repressed ROCK1 promoter activity. Electrophoretic mobility shift assay (EMSA), DNA pull down and chromatin immunoprecipitation (ChIP) assays revealed Sp1 can bind to this region. qRT-PCR and Western blotting research followed by overexpression or inhibition of Sp1 indicate that Sp1 can affect endogenous ROCK1 expression at both mRNA and protein levels. Overexpression of Sp1 can promote the expression of myogenic differentiation 1(MyoD), myogenin (MyoG), myosin heavy chain (MyHC). Taken together, we conclude that Sp1 positively regulates ROCK1 transcription by directly binding to the ROCK1 promoter region (from -604 to -532 bp) and may affect the process of myogenesis.

Dynamic transcriptome profiles of skeletal muscle tissue across 11 developmental stages for both Tongcheng and Yorkshire pigs.

BACKGROUND: The growth and development of skeletal muscle directly impacts the quantity and quality of pork production. Chinese indigenous pig breeds and exotic species vary greatly in terms of muscle production and performance traits. We present transcriptome profiles of 110 skeletal muscle samples from Tongcheng (TC) and Yorkshire (YK) pigs at 11 developmental periods (30, 40, 55, 63, 70, 90, and 105 days of gestation, and 0, 1, 3, and 5 weeks of age) using digital gene expression on Solexa/Illumina's Genome Analyzer platform to investigate the differences in prenatal and postnatal skeletal muscle between the two breeds. RESULTS: Muscle morphological changes indicate the importance of primary fiber formation from 30 to 40 dpc (days post coitus), and secondary fiber formation from 55 to 70 dpc. We screened 4,331 differentially expressed genes in TC and 2,259 in YK (log2 ratio >1 and probability >0.7). Cluster analysis showed different gene expression patterns between TC and YK pigs. The transcripts were annotated in terms of Gene Ontology related to muscle development. We found that the genes CXCL10, EIF2B5, PSMA6, FBXO32, and LOC100622249 played vital roles in the muscle regulatory networks in the TC breed, whereas the genes SGCD, ENG, THBD, AQP4, and BTG2 played dominant roles in the YK breed. These genes showed breed-specific and development-dependent differential expression patterns. Furthermore, 984 genes were identified in myogenesis. A heat map showed that significantly enriched pathways (FDR <0.05) had stage-specific functional regulatory mechanisms. Finally, the differentially expressed genes from our sequencing results were confirmed by real-time quantitative polymerase chain reaction. CONCLUSIONS: This study detected many functional genes and showed differences in the molecular mechanisms of skeletal muscle development between TC and YK pigs. TC pigs showed slower muscle growth and more complicated genetic regulation than YK pigs. Many differentially expressed genes showed breed-specific expression patterns. Our data provide a better understanding of skeletal muscle developmental differences and valuable information for improving pork quality.

Ectopic overexpression of porcine DGAT1 increases intramuscular fat content in mouse skeletal muscle.

The microsomal enzyme 1, 2-acyl CoA: diacylglyceroltransferase-1 (DGAT1) plays an important role in triglyceride storage in adipose tissue and expresses in skeletal muscle as well. The primary goal of the present study was to investigate the effect of porcine DGAT1 on intramuscular fat (IMF) content of transgenic mice produced by pronuclear microinjection with muscle specific promoter of porcine muscle creatine kinase (MCK). In normal chow-fed diet, 4 month-old male transgenic mice expressed more DGAT1, ACC1, UCP1, and FABP4 mRNAs and proteins in skeletal muscle than control mice by real-time PCR and western blot. No significant changes were detected for ACC2, CD36, ADRP, PPAR gamma and LPL. Triacylglycerol assay and soleus muscle sections showed overexpression of porcine DGAT1 in skeletal muscle increased intramyocellular triglyceride and percent of the total cell surface covered by lipid droplets. Thus, upregulation of porcine DGAT1 in skeletal muscle increases IMF content. The present study may further serve to develop transgenic pigs with higher IMF content and improved meat quality.

Molecular and functional characterization of glycogen synthase in the porcine satellite cells under insulin treatment.

Glycogen synthase (GS) catalyzes the key step of glycogen synthesis and plays an important role in glycogen metabolism in liver and muscle. In this study, we cloned the cDNA and promoter sequences of porcine glycogen synthesis genes (GYS1 and GYS2). Expression analysis revealed that porcine GYS1 was highly expressed in the skeletal muscle and heart. GYS2 was expressed specifically in liver and subcutaneous adipose tissue. The expression level of GYS1 was up-regulated from proliferation to differentiation in the porcine satellite cells, and insulin did not significantly affect the transcription of GYS1. Insulin stimulated 72-h-differentiated satellite cells as indicated by decrease in phosphorylation of GS, but did not affect GYS1 transcription and total GS protein level, suggesting that the effect of insulin is primarily mediated via posttranscriptional control rather than regulated at the transcriptional level. Four single-nucleotide polymorphisms (SNPs) were detected in the promoter and cDNA sequences of porcine GYS1. Association analyses revealed that the GYS1 Hin6I and MvaI polymorphisms both had significant associations (P < 0.05) with pH of M. longissimus dorsi (pHLD), M. biceps femoris (pHBF) and M. semipinalis capitis (pHSC) at 45 min postmortem. These results provide useful information for further investigation on the function of glycogen synthase in porcine skeletal muscle.

A 304 bp insertion/deletion mutation in promoter region induces the increase of porcine IDH3ß gene expression.

Obese and lean pig breeds show obvious differences in adipose metabolism/fat deposition; however, the molecular mechanism underlying phenotype variation remains unknown. In order to understand it, we analyzed the differences of gene expression in backfat between Meishan (a typical Chinese indigenous obese breed) and Large White (a lean Western breed) pigs. Here, we cloned porcine ß subunit of IDH3 (IDH3B) and 2447 bp 5'-flanking sequence of this gene, and determined the genomic structure. Porcine IDH3B contains three isoforms, IDH3B ( 1 ), IDH3B ( 2 ) and IDH3B ( 3 ). Real-time RT-PCR revealed that these three isoforms were prevalently up-regulated in backfat of western commercial pigs, Large White, Landrace and Duroc, compared with Chinese indigenous breeds, Meishan and Tongcheng pigs. A 304 bp insertion/deletion variant was found in the 5'-flanking region. Dual-luciferase reporter assays showed that in vitro the promoter of IDH3B gene with the insertion had higher luciferase activity as compared with the wild type. Three genotypes AA, AB and BB, due to this insertion, were detected, and the frequency of allele A was dominant in western commercial pigs, whereas allele B predominated in Chinese indigenous breeds. IDH3B mRNA expression in Meishan pigs was more abundant with genotype AA than with genotype AB or BB, as in Large White pigs. In addition, the polymorphism was detected in 317 pigs of a Large White × Meishan F2 resource population. Association analysis showed that pigs with genotype AA possessed higher backfat thickness at buttocks than those with genotype AB (P < 0.05) or BB. These data suggested that the 304 bp insertion mutation in promoter region increased the expression of porcine IDH3ß transcripts and this mutation might be a candidate marker for marker assistant selection in swine breeding.

Subcellular localization of different regions of porcine Six1 gene and its expression analysis in C2C12 myoblasts.

Six1 protein belongs to the Six homeoproteins family, exposing typical domain structure. Although the functions of Six1 have been drawn much attention, the roles of its individual domains are not completely elucidated. Here, we first detected the expression patterns of myogenin, MyoD, Myf5, and Six1 genes using real-time PCR in differentiating C2C12 cells cultured in differentiation medium for 2 or 6 days. The results showed that Six1 gene had the similar expression pattern with myogenin, MyoD, and Myf5 genes, which suggests that it may affect the myogenic differentiation. In order to evaluate the role of distinct domains of Six1 protein in subcellular localization, we constructed a series of truncated vectors tagged with green fluorescent proteins expressing various regions of porcine Six1 protein for subcellular localization analysis. Fluorescence confocal microscopy analysis showed that the different regions of Six1 protein displayed discrete distributions throughout the nucleus and the cytoplasm. The full-length CDS was exclusively localized in the nucleus and the individual HD domain was preferentially distributed to the nucleus both in C2C12 cells and in PK cells. However, the SD domain was diffusely distributed to the cytoplasm and the nucleus, and the localization of SD domain was biased to cytoplasm in C2C12 cells. Taken together, we conclude that the HD domain is important for the nuclear localization of porcine Six1 protein.

Heat Stress Impairs Maternal Endometrial Integrity and Results in Embryo Implantation Failure by Regulating Transport-Related Gene Expression in Tongcheng Pigs.

Heat stress (HS) poses a significant threat to production and survival in the global swine industry. However, the molecular regulatory effects of heat stress on maternal endometrial cells are poorly understood in pigs during early embryo implantation. In this study, we systematically examined morphological changes in the endometrium and the corresponding regulation mechanism in response to HS by combining scanning electron microscopy (SEM), hematoxylin/eosin (H&E) staining, western blot, and RNA-seq analyses. Our results showed that HS led to porcine endometrium damage and endometrial thinness during embryo implantation. The expression levels of cell adhesion-related proteins, including N-cadherin and E-cadherin, in the uterus were significantly lower in the heat stress group (39 ± 1 °C, n = 3) than in the control group (28 ± 1 °C, n = 3). A total of 338 up-regulated genes and 378 down-regulated genes were identified in porcine endometrium under HS. The down-regulated genes were found to be mainly enriched in the pathways related to the microtubule complex, immune system process, and metalloendopeptidase activity, whereas the up-regulated genes were mainly involved in calcium ion binding, the extracellular region, and molecular function regulation. S100A9 was found to be one of the most significant differentially expressed genes (DEGs) in the endometrium under HS, and this gene could promote proliferation of endometrial cells and inhibit their apoptosis. Meanwhile, HS caused endometrial epithelial cell (EEC) damage and inhibited its proliferation. Overall, our results demonstrated that HS induced uterine morphological change and tissue damage by regulating the expression of genes associated with calcium ions and amino acid transport. These findings may provide novel molecular insights into endometrial damage under HS during embryo implantation.

Transcriptome regulation of extracellular vesicles derived from porcine uterine flushing fluids during peri-implantation on endometrial epithelial cells and embryonic trophoblast cells.

The extracellular vesicles (EVs) in uterine fluids play a vital role in embryo implantation by mediating intrauterine communication between conceptus and maternal endometrium in pigs. However, the regulatory mechanism of EVs in uterine fluids is largely unclear. In order to understand the effect of EVs in uterine flushing fluids (UFs) during embryo implantation on endometrial epithelial cells (EECs) and embryonic trophoblast cells (PTr2 cells). The UFs-EVs on day 13 of pregnancy (D13) were added to the culture medium of EECs and PTr2 cells. It was found that PKH-67 labeled UFs-EVs could be taken up in EECs and PTr2 cells. Transcriptome sequencing analysis showed that a total of 1793 and 6279 genes were differentially expressed in the EECs and PTr2 cells after the treatment of UFs-EVs on D13, respectively. Among these genes, real-time quantitative PCR (RT-qPCR) results indicated that ID2, ITGA5, CXCL10 and CXCL11 genes were differentially expressed in both EECs and PTr2 cells after treatment. Bioinformatics analysis showed that the differentially expressed (DE) genes in EECs and PTr2 cells after treatment are involved in immune regulation, cell migration, cell adhesion and the secretion and uptake of EVs. Our research offers novel insight into the regulation mechanism of UFs-EVs on D13 in EECs and PTr2 cells.

Immunotoxicity and uterine transcriptome analysis of the effect of zearalenone (ZEA) in sows during the embryo attachment period.

Zearalenone is a mycotoxin and a pollutant that is commonly found in crops. Once ingested, ZEA can cause disturbances in the immune system and produce immunotoxicity. However, there is little research on the effect of ZEA exposure on the relationship between immune regulation and embryo implantation in the uteri of sows. Embryo implantation relies upon the fact that the relationship between the maternal and fetal immune systems is balanced. This balance is provided by the joint regulation of immune organs, cytokines, and uterine immunity. In this study, we investigated 20 sows with an initial weight of 100.00 ± 5.00 kg and 200 days in age. The sows were fed with diets containing ZEA at concentrations of 0 mg/kg, 1 mg/kg, 2 mg/kg, and 10 mg/kg, respectively, from 8 to 14 days of gestation. We studied immunotoxicity and the uterine transcriptomics associated with the effect of ZEA in sows during embryo attachment. Following ZEA treatment, serum biochemical analysis and RT-qPCR were used to detect the concentration and mRNA expression levels of immunoglobulin IgA, IgG, and IgM, in the serum and spleen, respectively. The same analysis was carried out for a range of cytokines in the serum and spleen: IL-1, IL-2, IL-6, IL-10, and TNF. Uterine transcriptome analysis revealed 75, 215, and 81 genes that were differentially expressed in the 0 mg/kg vs 1 mg/kg treatment, 0 mg/kg vs 10 mg/kg treatment, and 1 mg/kg vs 10 mg/kg treatment, respectively. GO terms analysis showed that the up-regulated genes related to the immune system were highly expressed. KEGG pathway analysis further revealed the importance of several metabolic pathways, including drug metabolism-cytochrome P450, the cytokine-cytokine receptor interaction pathway, and calcium signaling pathways. The differentially expressed genes were confirmed by quantitative real-time PCR. These findings expand our understanding of the gene expression profiles and signaling pathways associated with the immune response to ZEA exposure in sows during the embryo implantation window. This study provides valuable information for clarifying the molecular mechanism of ZEA's immunotoxicity to early pregnant sows in the future.

Genome-Wide Association Study Reveals Additive and Non-Additive Effects on Growth Traits in Duroc Pigs.

Growth rate plays a critical role in the pig industry and is related to quantitative traits controlled by many genes. Here, we aimed to identify causative mutations and candidate genes responsible for pig growth traits. In this study, 2360 Duroc pigs were used to detect significant additive, dominance, and epistatic effects associated with growth traits. As a result, a total number of 32 significant SNPs for additive or dominance effects were found to be associated with various factors, including adjusted age at a specified weight (AGE), average daily gain (ADG), backfat thickness (BF), and loin muscle depth (LMD). In addition, the detected additive significant SNPs explained 2.49%, 3.02%, 3.18%, and 1.96% of the deregressed estimated breeding value (DEBV) variance for AGE, ADG, BF, and LMD, respectively, while significant dominance SNPs could explain 2.24%, 13.26%, and 4.08% of AGE, BF, and LMD, respectively. Meanwhile, a total of 805 significant epistatic effects SNPs were associated with one of ADG, AGE, and LMD, from which 11 sub-networks were constructed. In total, 46 potential genes involved in muscle development, fat deposition, and regulation of cell growth were considered as candidates for growth traits, including CD55 and NRIP1 for AGE and ADG, TRIP11 and MIS2 for BF, and VRTN and ZEB2 for LMD, respectively. Generally, in this study, we detected both new and reported variants and potential candidate genes for growth traits of Duroc pigs, which might to be taken into account in future molecular breeding programs to improve the growth performance of pigs.

Developmental expression changes of the genes involved in IGFI signaling pathway in longissimus dorsi muscle of Tongcheng and Yorkshire pigs during postnatal growth.

IGFI signaling pathway is sufficient to regulate myofibre hypertrophy postnatally, which is associated with muscle mass in economically livestock. In the present study, we drafted the developmental expression pattern of eight genes implicated in IGFI system across six stages of postnatal myofibre growth in Yorkshire and Tongcheng pigs. The results indicated that GRB2 may contribute to increased DNA content in postnatal myofibre hypertrophy via GRB2-Ras-Raf-MEK-ERK sub-pathway; INSR, PDK1, IRS1 and eIF4E may contribute to high growth rate via stimulating the rate of protein synthesis and inhibiting the rate of protein degradation. In addition, the results suggested 60 days maybe a very important stage in postnatal myofibre growth. Moreover, higher mRNA level of IRS1 and GLUT4 maybe associated with inferior meat quality in Yorkshire compared to Tongcheng pig. Therefore, IGFI signaling pathway regulates myofibre hypertrophy postnatally via complicated signal effectors, which may have negative impact on meat quality simultaneously.