Expression pattern of zinc-finger transcription factor Odd-skipped related 2 in murine development and neonatal stage

Intestinal expression patterns of transcription factors and markers for interstitial cells in the larval zebrafish

For the digestion of food, it is important for the gut to be differentiated regionally and to have proper motor control. However, the number of transcription factors that regulate its development is still limited. Meanwhile, the interstitial cells of the gastrointestinal (GI) tract are necessary for intestinal motility in addition to the enteric nervous system. There are anoctamine1 (Ano1)-positive and platelet-derived growth factor receptor α (Pdgfra)-positive interstitial cells in mammal, but Pdgfra-positive cells have not been reported in the zebrafish. To identify new transcription factors involved in GI tract development, we used RNA sequencing comparing between larval and adult gut. We isolated 40 transcription factors that were more highly expressed in the larval gut. We demonstrated expression patterns of the 13 genes, 7 of which were newly found to be expressed in the zebrafish larval gut. Six of the 13 genes encode nuclear receptors. The osr2 is expressed in the anterior part, while foxP4 in its distal part. Also, we reported the expression pattern of pdgfra for the first time in the larval zebrafish gut. Our data provide fundamental knowledge for studying vertebrate gut regionalization and motility by live imaging using zebrafish.

Alterations in ileal transcriptomics during an intestinal barrier challenge in lactating Holstein cows fed a Saccharomyces cerevisiae fermentation product identify potential regulatory processes

Stressors such as lack of access to feed, hot temperatures, transportation, and pen changes can cause impairment of ruminal and intestinal barrier function, also known as "leaky gut". Despite the known benefits of some nutritional approaches during periods of stress, little is understood regarding the underlying mechanisms, especially in dairy cows. We evaluated the effect of feeding a Saccharomyces cerevisiae fermentation product (SCFP; NutriTek, Diamond V, Cedar Rapids, IA) on the ileal transcriptome in response to feed restriction (FR), an established model to induce intestinal barrier dysfunction. Multiparous cows [97.1 ± 7.6 days in milk (DIM); n = 5/group] fed a control diet or control plus 19 g/d SCFP for 9 wk were subjected to an FR challenge for 5 d during which they were fed 40% of their ad libitum intake from the 7 d before FR. All cows were slaughtered at the end of FR, and ileal scrapping RNA was used for RNAseq (NovaSeq 6000, 100 bp read length). Statistical analysis was performed in R and bioinformatics using the KEGG (Kyoto Encyclopedia of Genes and Genomes) and GO databases. One thousand six hundred and ninety-six differentially expressed genes (DEG; FDR-adjusted P ≤ 0.10) were detected in SCFP vs. control, with 451 upregulated and 1,245 downregulated. "Mucin type O-glycan biosynthesis" was the top downregulated KEGG pathway due to downregulation of genes catalyzing glycosylation of mucins (GCNT3, GALNT5, B3GNT3, GALNT18, and GALNT14). An overall downregulation of cell and tissue structure genes (e.g., extracellular matrix proteins) associated with collagen (COL6A1, COL1A1, COL4A1, COL1A2, and COL6A2), laminin (LAMB2), and integrins (ITGA8, ITGA2, and ITGA5) also were detected with SCFP. A subset of DEG enriched in the GO term "extracellular exosome" and "extracellular space". Chemokines within "Cytokine-cytokine receptor interaction pathways" such as CCL16, CCL21, CCL14, CXCL12, and CXCL14 were downregulated by SCFP. The "Glutathione metabolism" pathway was upregulated by SCFP, including GSTA1 and RRM2B among the top upregulated genes, and GSTM1 and GPX8 as top downregulated genes. There were 9 homeobox transcription factors among the top 50 predicted transcription factors using the RNAseq DEG dataset, underscoring the importance of cell differentiation as a potential target of dietary SCFP. Taken together, SCFP downregulated immune-, ECM-, and mucin synthesis-related genes during FR. Homeobox transcription factors appear important for the transcriptional response of SCFP.

Dissecting human embryonic skeletal stem cell ontogeny by single-cell transcriptomic and functional analyses

Human skeletal stem cells (SSCs) have been discovered in fetal and adult long bones. However, the spatiotemporal ontogeny of human embryonic SSCs during early skeletogenesis remains elusive. Here we map the transcriptional landscape of human limb buds and embryonic long bones at single-cell resolution to address this fundamental question. We found remarkable heterogeneity within human limb bud mesenchyme and epithelium, and aligned them along the proximal–distal and anterior–posterior axes using known marker genes. Osteo-chondrogenic progenitors first appeared in the core limb bud mesenchyme, which give rise to multiple populations of stem/progenitor cells in embryonic long bones undergoing endochondral ossification. Importantly, a perichondrial embryonic skeletal stem/progenitor cell (eSSPC) subset was identified, which could self-renew and generate the osteochondral lineage cells, but not adipocytes or hematopoietic stroma. eSSPCs are marked by the adhesion molecule CADM1 and highly enriched with FOXP1/2 transcriptional network. Interestingly, neural crest-derived cells with similar phenotypic markers and transcriptional networks were also found in the sagittal suture of human embryonic calvaria. Taken together, this study revealed the cellular heterogeneity and lineage hierarchy during human embryonic skeletogenesis, and identified distinct skeletal stem/progenitor cells that orchestrate endochondral and intramembranous ossification.

Zinc-finger transcription factor Odd-skipped related 1 regulates cranial bone formation

Knowledge of the molecular mechanisms of bone formation has been advanced by novel findings related to genetic control. Odd-skipped related 1 (Osr1) is known to play important roles in embryonic, heart, and urogenital development. To elucidate the in vivo function of Osr1 in bone formation, we generated transgenic mice overexpressing full-length Osr1 under control of its 2.8-kb promoter, which were smaller than their wild-type littermates. Notably, abnormalities in the skull of Osr1 transgenic mice were revealed by analysis of X-ray, skeletal preparation, and morphological findings, including round skull and cranial dysraphism. Furthermore, primary calvarial cells obtained from these mice showed increased proliferation and expression of chondrocyte markers, while expression of osteoblast markers was decreased. BMP2 reduced Osr1 expression and Osr1 knockdown by siRNA-induced alkaline phosphatase and osteocalcin expression in mesenchymal and osteoblastic cells. Together, our results suggest that Osr1 plays a coordinating role in appropriate skull closure and cranial bone formation by negative regulation.

Genetic and Functional Analyses of Two Missense Mutations in the Transcription Factor FOXL2 in Two Chinese Families with Blepharophimosis-Ptosis-Epicanthus Inversus Syndrome

BACKGROUND

Blepharophimosis-ptosis-epicanthus inversus syndrome (BPES) is a rare autosomal-dominant inherited disease. This study was carried out to investigate the genetic and functional changes within the FOXL2 gene in two Chinese families with BPES.

MATERIALS AND METHODS

DNA was extracted from the peripheral blood of 26 persons from two different Chinese BPES families (13 of which were affected), as well as 200 cataract patients to act as normal controls. FOXL2 gene mutations were detected using polymerase chain reaction (PCR) and DNA sequencing techniques. Bioinformatic analyses were performed to analyze the structures and functions of the mutant proteins. Wild-type and mutant FOXL2 genes were subcloned into pEGFP-N1 and pCDB vectors and then transfected into COS7 and HEK293T cell lines. We observed protein subcellular localization, and used quantitative real-time (qRT)-PCR and western blots to assess regulation of the target OSR2 gene.

RESULTS

We detected two novel missense mutations, c.162G>T (p.Lys54Asn) and c.308G>A (p.Arg103His), in the FOXL2 gene; one in each of the study families. Bioinformatic analyses indicated no obvious differences between the wild-type and mutant protein structures. However, they did predict that the two mutations were likely damaging to protein function. We found that the two mutated proteins were both largely distributed within the nucleus and that there was little found in the cytoplasm. The OSR2 mRNA content decreased significantly when the plasmids carrying the c.162G>T and c.308G>A were transfected into COS7 and HEK293 cell lines, when compared to the empty and the wild-type FOXL2 carrier. Western blot analyses indicated, that after transfecting the c.162G>T mutation, the OSR2 protein level was relatively similar to the wild-type, but that the cells transfected with the c.308G>A mutation showed significantly decreased levels of the OSR2 protein.

CONCLUSIONS

Our study broadens the BPES gene mutation spectrum and suggests a possible mechanism of action. It also provides reference data for the further studies of BPES.

Identification of Long Non-Coding RNAs Related to Skeletal Muscle Development in Two Rabbit Breeds with Different Growth Rate

Skeletal muscle development plays an important role in muscle quality and yield, which decides the economic value of livestock. Long non-coding RNAs (lncRNAs) have been reported to be associated with skeletal muscle development. However, little is revealed about the function of lncRNAs in rabbits' muscle development. LncRNAs and mRNAs in two rabbit breeds (ZIKA rabbits (ZKR) and Qixin rabbits (QXR)) with different growth rates at three developmental stages (0 day, 35 days, and 84 days after birth) were researched by transcriptome sequencing. Differentially expressed lncRNAs and mRNAs were identified for two rabbit breeds at the same stages by DESeq package. Co-expression correlation analysis of differentially expressed lncRNAs and mRNAs were performed to construct lncRNA⁻mRNA pairs. To explore the function of lncRNAs, Gene Ontology (GO) analysis of co-expression mRNAs in lncRNA⁻mRNA pairs were performed. In three comparisons, there were 128, 109, and 115 differentially expressed lncRNAs, respectively. LncRNAs TCONS_00013557 and XR_518424.2 differentially expressed in the two rabbit breeds might play important roles in skeletal muscle development, for their co-expressed mRNAs were significantly enriched in skeletal muscle development related GO terms. This study provides potentially functional lncRNAs in skeletal muscle development of two rabbit breeds and might be beneficial to the production of rabbits.