SMAD7, an antagonist of TGF-beta signaling, is a candidate of prenatal skeletal muscle development and weaning weight in pigs

Exosomes for gene therapy effectively inhibit the endothelial-mesenchymal transition in mouse aortic endothelial cells

Background

Heterotopic ossification (HO) can limit joint activity, causes ankylosis and impairs the function and rehabilitation of patients. Endothelial to mesenchymal transition (EndMT) plays an important role in the pathogenesis of HO, and high expression of SMAD7(Mothers Against Decapentaplegic Homolog 7) in endothelial cells can effectively reverse the TGF-β1 mediated EndMT. This article studied an appropriately engineered exosome with high biocompatibility and good targeting property to administrate SMAD7 gene therapy to inhibit the EndMT.

Methods

Exosomes from mouse aortic endothelial cells were cultured and harvested. DSPE-PEG and antibody CD34 were combined to exosomes to synthesize the endothelial cell targeting exosome vector (Exosome-DSPE-PEG-AbCD34). The biocompatibility, stability, targeting and cell internalization of exosome vector were tested, then the Exosome-DSPE-PEG-AbCD34 was loaded with Smad7 plasmid and administrated to MAECs to examine its therapeutic effect on EndMT of MAEC mediated by TGF-β1.

Results

The Exosome-DSPE-PEG-AbCD34 has no impact on MAEC cell viability at high concentration, and exosome-DSPE-PEG-Ab_CD34 could be stably stored at 4°C and 37°C for at least 8 days. Exosome-DSPE-PEG-Ab_CD34 has better targeting property to MAEC cells and can enter into the cells more effectively. The Exosome-DSPE-PEG-Ab_CD34-Smad7 could significantly increase the level of SMAD7, decrease the expression of TGF-β1, and effectively reverse the EndMT of MAEC mediated by TGF- β1 in MAEC cells.

Conclusions

The synthesized Exosome-DSPE-PEG-AbCD34-Smad7 has good biological properties and can effectively reverse the EndMT of MAEC mediated by TGF-β1. Thus, Exosome-DSPE-PEG-AbCD34-Smad7 may has the potential for the prevention and treatment of HO.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04896-0.

Cadmium exposure activates the PI3K/AKT signaling pathway through miRNA-21, induces an increase in M1 polarization of macrophages, and leads to fibrosis of pig liver tissue

Cadmium (Cd) is a toxic substance that pollutes the environment with multiple organs. Long-term exposure to Cd can cause fibrosis in the lungs and other organs of animal body. This article explored the effects of subacute Cd exposure on pig liver fibrosis, as well as the polarization of microRNA (miRNA) and M1/M2 macrophages during this process. Based on the establishment of the pig subacute CdCl2 exposure model, we used immunofluorescence staining, Masson staining, qRT-PCR and western blotting to conduct further research. The results showed that Cd exposure can increase the expression of miRNA-21, decrease the expression of TGF-β and SMAD7, increase the expression of PI3K/AKT signaling pathway, cause the M1/M2 imbalance and the increase of M1 polarization. Meantime, it causes the secretion of inflammatory cytokines (TNF-α, IL-1β, and IL-6), and causes an imbalance in the expression of TIMP1, MMP2, and MMP9, which are related to the degree of fibrosis. And the expression of α-SMA, COL1 and COL3 were up-regulated. In the pig, these results indicate that liver fibrosis caused by subacute CdCl2 exposure is induced by the M1 polarization of macrophages through the PI3K/AKT signaling pathway activated by miRNA-21 signaling pathway. These research results not only enrich the theoretical basis and reference value of Cd toxicology research, but also provide new references and new research ideas for comparative medicine.

Identification and expression pattern analysis of miRNAs in pectoral muscle during pigeon (Columba livia) development

MicroRNAs (miRNAs) are a group of crucial regulators in the process of animal growth and development. However, little is known about the expression and function of miRNAs in pigeon muscles. To identify the miRNAs participating in the rapid development of pigeon pectoral muscles and quantitate their expression levels of pectoral muscles in different age stages, we performed miRNA transcriptome analysis in pigeon pectoral muscles by sequencing small RNAs over three different age stages (1-day old, 28 days old, and 2 years old). Dual-luciferase reporter assay was applied to validate the interaction between miRNA and its target gene. We identified 304 known miRNAs, 201 conserved miRNAs, and 86 novel miRNAs in pigeon pectoral muscles. 189 differentially expressed (DE) miRNAs were screened out during pigeon development. A short time-series expression miner (STEM) analysis indicated 89 DE miRNAs were significantly clustered in a progressively decreasing expression profile, and mainly enriched in biosynthesis-related GO categories and signaling pathways for MAPK and TGF-β. Dual-luciferase reporter assay indicated that a progressively down-regulated miRNA (miR-20b-5p) could directly target Krüppel-like factor 3 (KLF3) gene. To sum-up, our data expand the repertoire of pigeon miRNAs and enhance understanding of the mechanisms underlying rapid development in squabs.

BAMBI shuttling between cytosol and membrane is required for skeletal muscle development and regeneration

Bone morphogenetic protein and activin membrane-bound inhibitor (BAMBI) gene encodes a transmembrane protein and is involved in multiple physiological and pathological processes, such as inflammatory response, tumor development and progression, cell proliferation and differentiation. A previous study suggested that BAMBI may interact with the Wnt/β-catenin signaling pathway via promoting β-catenin nuclear translocation associated with C2C12 myogenic myoblast differentiation. However, its biological function in skeletal muscle still remains unknown and requires further characterization. The present work sought to investigate its biological function in skeletal muscle, especially the physiological roles of BAMBI during skeletal muscle growth and regeneration. Our current work suggests that BAMBI protein is highly expressed in skeletal muscle and is only detected in cytosolic fraction in the resting muscle. Moreover, BAMBI protein is co-localized in fast-twitch (glycolytic) fibers, but not in slow-twitch (oxidative) fibers. Comparing with the cytosolic trapping in resting muscle, BAMBI protein is enriched on cellular membrane during the muscle growth and regeneration, suggesting that BAMBI-mediated a significant signaling pathway may be an essential part of muscle growth and regeneration.

Genome-Wide Association Study of Piglet Uniformity and Farrowing Interval

Piglet uniformity (PU) and farrowing interval (FI) are important reproductive traits related to production and economic profits in the pig industry. However, the genetic architecture of the longitudinal trends of reproductive traits still remains elusive. Herein, we performed a genome-wide association study (GWAS) to detect potential genetic variation and candidate genes underlying the phenotypic records at different parities for PU and FI in a population of 884 Large White pigs. In total, 12 significant SNPs were detected on SSC1, 3, 4, 9, and 14, which collectively explained 1–1.79% of the phenotypic variance for PU from parity 1 to 4, and 2.58–4.11% for FI at different stages. Of these, seven SNPs were located within 16 QTL regions related to swine reproductive traits. One QTL region was associated with birth body weight (related to PU) and contained the peak SNP MARC0040730, and another was associated with plasma FSH concentration (related to FI) and contained the SNP MARC0031325. Finally, some positional candidate genes for PU and FI were identified because of their roles in prenatal skeletal muscle development, fetal energy substrate, pre-implantation, and the expression of mammary gland epithelium. Identification of novel variants and candidate genes will greatly advance our understanding of the genetic mechanisms of PU and FI, and suggest a specific opportunity for improving marker assisted selection or genomic selection in pigs.