Enhanced cultivation of chicken primordial germ cells.

The cultivation and expansion of chicken primordial germ cells (cPGCs) are of critical importance for both biotechnological applications and the management of poultry genetic biodiversity. The feeder-free culture system has become the most popular approach for the cultivation and expansion of cPGCs. However, despite some success in the cultivation of cPGCs, the reproducibility of culture conditions across different laboratories remains a challenge. This study aimed to compare two defined and enriched media for the growth of cPGCs originating from the Hubbard JA57 broiler. To this end, cPGCs were isolated from the embryonic blood of Hamburger-Hamilton (HH) stages 14-16 and cultured at various time points. The Growth properties and characteristics of these cells were evaluated in two different culture conditions (the defined or enriched medium) and their migratory properties were assessed after genetic engineering and injection into the vasculature of 2.5-day-old chicken embryos. The main finding of this study was that the use of an enriched medium (the defined medium with Knock-Out Serum Replacement; KOSR) resulted in improved growth properties of cPGCs originating from the Hubbard JA57 broiler compared to a defined medium. The ability to cultivate and expand cPGCs is crucial for the generation of both genetically engineered birds and breeds of interest from local or commercial origins. Therefore, these results highlight the importance of choosing an appropriate culture medium for cPGCs growth and expansion.

Study of the regulatory elements of the Ovalbumin gene promoter using CRISPR technology in chicken cells.

BACKGROUND: Hormone-dependent promoters are very efficient in transgene expression. Plasmid-based reporter assays have identified regulatory sequences of the Ovalbumin promoter that are involved in response to estrogen and have shown that the deletion of the steroid-dependent regulatory element (SDRE) and negative regulatory element (NRE) leads to a steroid-independent expression of a reporter. However, the functional roles of these regulatory elements within the native genomic context of the Ovalbumin promoter have not been evaluated. RESULTS: In this study, we show that the negative effects of the NRE element on the Ovalbumin gene can be counteracted by CRISPR interference. We also show that the CRISPR-mediated deletion of SDRE and NRE promoter elements in a non-oviduct cell can lead to the significant expression of the Ovalbumin gene. In addition, the targeted knock-in of a transgene reporter in the Ovalbumin coding region and its expression confirms that the truncated promoter of the Ovalbumin gene can be efficiently used for an estrogen-independent expression of a foreign gene. CONCLUSIONS: The methodology applied in this paper allowed the study of promoter regulatory sequences in their native nuclear organization.

Integrating Omics and CRISPR Technology for Identification and Verification of Genomic Safe Harbor Loci in the Chicken Genome.

BACKGROUND: One of the most prominent questions in the field of transgenesis is 'Where in the genome to integrate a transgene?'. Escape from epigenetic silencing and promoter shutdown of the transgene needs reliable genomic safe harbor (GSH) loci. Advances in genome engineering technologies combined with multi-omics bioinformatics data have enabled rational evaluation of GSH loci in the host genome. Currently, no validated GSH loci have been evaluated in the chicken genome. RESULTS: Here, we analyzed and experimentally examined two GSH loci in the genome of chicken cells. To this end, putative GSH loci including chicken HIPP-like (cHIPP; between DRG1 and EIF4ENIF1 genes) and chicken ROSA-like (cROSA; upstream of the THUMPD3 gene) were predicted using multi-omics bioinformatics data. Then, the durable expression of the transgene was validated by experimental characterization of continuously-cultured isogenous cell clones harboring DsRed2-ΔCMV-EGFP cassette in the predicted loci. The weakened form of the CMV promoter (ΔCMV) allowed the precise evaluation of GSH loci in a locus-dependent manner compared to the full-length CMV promoter. CONCLUSIONS: cHIPP and cROSA loci introduced in this study can be reliably exploited for consistent bio-manufacturing of recombinant proteins in the genetically-engineered chickens. Also, results showed that the genomic context dictates the expression of transgene controlled by ΔCMV in GSH loci.

Genetically engineered birds; pre-CRISPR and CRISPR era†.

Generating biopharmaceuticals in genetically engineered bioreactors continues to reign supreme. Hence, genetically engineered birds have attracted considerable attention from the biopharmaceutical industry. Fairly recent genome engineering methods have made genome manipulation an easy and affordable task. In this review, we first provide a broad overview of the approaches and main impediments ahead of generating efficient and reliable genetically engineered birds, and various factors that affect the fate of a transgene. This section provides an essential background for the rest of the review, in which we discuss and compare different genome manipulation methods in the pre-clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR era in the field of avian genome engineering.

CRISPR/dCas9-mediated transposition with specificity and efficiency of site-directed genomic insertions.

The ability and efficiency of targeted nucleases to perform sequence replacements or insertions into the genome are limited. This limited efficiency for sequence replacements or insertions can be explained by the dependency on DNA repair pathways, the possibility of cellular toxicity, and unwanted activation of proto-oncogenes. The piggyBac (PB) transposase uses a very efficient enzymatic mechanism to integrate DNA fragments into the genome in a random manner. In this study, we fused an RNA-guided catalytically inactive Cas9 (dCas9) to the PB transposase and used dual sgRNAs to localize this molecule to specific genomic targets. We designed and used a promoter/reporter complementation assay to register and recover cells harboring-specific integrations, where only by complementation upon correct genomic integration, the reporter can be activated. Using an RNA-guided piggyBac transposase and dual sgRNAs, we were able to achieve site-directed integrations in the human ROSA26 safe harbor region in 0.32% of cells. These findings show that the methodology used in this study can be used for targeting genomic regions. An application for this finding could be in cancer cells to insert sequences into specific target regions that are intended to be destroyed, or to place promoter cargos behind the tumor suppressor genes to activate them.

Improved Survival and Hematopoietic Differentiation of Murine Embryonic Stem Cells on Electrospun Polycaprolactone Nanofiber.

OBJECTIVE: Three-dimensional (3D) biomimetic nanofiber scaffolds have widespread ap- plications in biomedical tissue engineering. They provide a suitable environment for cel- lular adhesion, survival, proliferation and differentiation, guide new tissue formation and development, and are one of the outstanding goals of tissue engineering. Electrospinning has recently emerged as a leading technique for producing biomimetic scaffolds with mi- cro to nanoscale topography and a high porosity similar to the natural extracellular matrix (ECM). These scaffolds are comprised of synthetic and natural polymers for tissue engi- neering applications. Several kinds of cells such as human embryonic stem cells (hESCs) and mouse ESCs (mESCs) have been cultured and differentiated on nanofiber scaffolds. mESCs can be induced to differentiate into a particular cell lineage when cultured as em- bryoid bodies (EBs) on nano-sized scaffolds. MATERIALS AND METHODS: We cultured mESCs (2500 cells/100 µl) in 96-well plates with knockout Dulbecco's modified eagle medium (DMEM-KO) and Roswell Park Memorial Institute-1640 (RPMI-1640), both supplemented with 20% ESC grade fetal bovine serum (FBS) and essential factors in the presence of leukemia inhibitory factor (LIF). mESCs were seeded at a density of 2500 cells/100 µl onto electrospun polycaprolactone (PCL) nanofibers in 96-well plates. The control group comprised mESCs grown on tissue cul- ture plates (TCP) at a density of 2500 cells/100 µl. Differentiation of mESCs into mouse hematopoietic stem cells (mHSCs) was performed by stem cell factor (SCF), interleukin-3 (IL-3), IL-6 and Fms-related tyrosine kinase ligand (Flt3-L) cytokines for both the PCL and TCP groups. We performed an experimental study of mESCs differentiation. RESULTS: PCL was compared to conventional TCP for survival and differentiation of mESCs to mHSCs. There were significantly more mESCs in the PCL group. Flowcyto- metric analysis revealed differences in hematopoietic differentiation between the PCL and TCP culture systems. There were more CD34+(Sca1+) and CD133+cells subpopulations in the PCL group compared to the conventional TCP culture system. CONCLUSION: The nanofiber scaffold, as an effective surface, improves survival and differentiation of mESCs into mHSCs compared to gelatin coated TCP. More studies are necessary to understand how the topographical features of electrospun fibers af- fect cell growth and behavior. This can be achieved by designing biomimetic scaffolds for tissue engineering.

The Effect of Hypoxia on Mesenchymal Stem Cell Biology.

Although physiological and pathological role of hypoxia have been appreciated in mammalians for decades however the cellular biology of hypoxia more clarified in the past 20 years. Discovery of the transcription factor hypoxia-inducible factor (HIF)-1, in the 1990s opened a new window to investigate the mechanisms behind hypoxia. In different cellular contexts HIF-1 activation show variable results by impacting various aspects of cell biology such as cell cycle, apoptosis, differentiation and etc. Mesenchymal stem cells (MSC) are unique cells which take important role in tissue regeneration. They are characterized by self-renewal capacity, multilineage potential, and immunosuppressive property. Like so many kind of cells, hypoxia induces different responses in MSCs by HIF- 1 activation. The activation of this molecule changes the growth, multiplication, differentiation and gene expression profile of MSCs in their niche by a complex of signals. This article briefly discusses the most important effects of hypoxia in growth kinetics, signalling pathways, cytokine secretion profile and expression of chemokine receptors in different conditions.

Effect of Superparamagnetic Iron Oxide Nanoparticles-Labeling on Mouse Embryonic Stem Cells.

OBJECTIVE: Superparamagnetic iron oxide nanoparticles (SPIONs) have been used to label mammalian cells and to monitor their fate in vivo using magnetic resonance imaging (MRI). However, the effectiveness of phenotype of labeled cells by SPIONs is still a matter of question. The aim of this study was to investigate the efficiency and biological effects of labeled mouse embryonic stem cells (mESCs) using ferumoxide- protamine sulfate complex. MATERIALS AND METHODS: In an experimental study, undifferentiated mESCs, C571 line, a generous gift of Stem Cell Technology Company, were cultured on gelatin-coated flasks. The proliferation and viability of SPION-labeled cells were compared with control. ESCs and embryoid bodies (EBs) derived from differentiated hematopoietic stem cells (HSCs) were analyzed for stage-specific cell surface markers using fluorescence-activated cell sorting (FACS). RESULTS: Our observations showed that SPIONs have no effect on the self-renewal ability of mESCs. Reverse microscopic observations and prussian blue staining revealed 100% of cells were labeled with iron particles. SPION-labeled mESCs did not significantly alter cell viability and proliferation activity. Furthermore, labeling did not alter expression of representative surface phenotypic markers such as stage-specific embryonic antigen 1 (SSEA1) and cluster of differentiation 117 (CD117) on undifferentiated ESC and CD34, CD38 on HSCs, as measured by flowcytometry. CONCLUSION: According to the results of the present study, SPIONs-labeling method as MRI agents in mESCs has no negative effects on growth, morphology, viability, proliferation and differentiation that can be monitored in vivo, noninvasively. Noninvasive cell tracking methods are considered as new perspectives in cell therapy for clinical use and as an easy method for evaluating the placement of stem cells after transplantation.

The Effect of Baicalin as A PPAR Activator on Erythroid Differentiation of CD133(+)Hematopoietic Stem Cells in Umbilical Cord Blood.

OBJECTIVE: The peroxisome proliferator-activated receptors (PPARs) are a group of nu- clear receptor proteins whose functions as transcription factors regulate gene expres- sions. PPARs play essential roles in the regulation of cellular differentiation, development, and metabolism (carbohydrate, lipid, protein), and tumorigenesis of higher organisms. This study attempts to determine the effect of baicalin, a PPARγ activator, on erythroid differentiation of cluster of differentiation 133(+)(CD133(+)) cord blood hematopoietic stem cells (HSCs). MATERIALS AND METHODS: In this experimental study, in order to investigate the effects of the PPARγ agonists baicalin and troglitazone on erythropoiesis, we isolated CD133(+) cells from human umbilical cord blood using the MACS method. Isolated cells were cultured in erythroid-inducing medium with or without various amounts of the two PPARγ activa- tors (baicalin and troglitazone). Erythroid differentiation of CD133(+)cord blood HSCs were assessed using microscopic morphology analysis, flow cytometric analysis of erythroid surface markers transferrin receptor (TfR) and glycophorin A (GPA) and bycolony forming assay. RESULTS: Microscopic and flow cytometric analysis revealed the erythroid differentiation of CD133(+)cord blood HSCs under applied erythroid inducing conditions. Our flow cytometric data showed that the TfR and GPA positive cell population diminished significantly in the presence of either troglitazone or baicalin. The suppression of erythroid differentiation in response to PPARγ agonists was dose-dependent. Erythroid colony-forming ability of HSC decreased significantly after treatment with both PPARγ agonists but troglitazone had a markedly greater effect. CONCLUSION: Our results have demonstrated that PPARγ agonists modulate erythroid dif- ferentiation of CD133(+)HSCs, and therefore play an important role in regulation of normal erythropoiesis under physiologic conditions. Thus, considering the availability and applica- tion of this herbal remedy for treatment of a wide range of diseases, the inhibitory effect of baicalin on erythropoiesis should be noted.

Prevalence and Causes of Cesarean Section in Iran: Systematic Review and Meta-Analysis.

Unfortunately, the prevalence of cesarean section has increased in recent years. Whereas awareness of the prevalence and causes is inevitable for planning and effective interventions, so aim of this study has designed and conducted for reviewing of systematic Prevalence and caesarean causes in Iran. In this meta-analysis, the required information have been collected using several keywords which are Cesarean section rate, Cesarean section prevalence, delivery, childhood, childbirth, relative causes, relative frequency, Iran and their Persian equivalents have been collected from databases such as CINAHL, Science Direct, PubMed, Magiran, SID, Iranmedex. Finally, we found 706 related articles and selected 34 articles among them for studying of cesarean Prevalence. We used CMA software with random model for Meta-Analysis. The prevalence of Cesarean was estimated48%. Using content analysis, Factors influencing the incidence of cesarean section were divided to 3 categories including social and demographic factors, obstetric-medical causes and non-obstetric-medical causes. Maternal education and grand multiparity in the field of demographic and social factors, previous cesarean in the field of obstetric-medical causes and fear of normal-vaginal delivery (NVD) and doctor's suggestion in the field of non-obstetric-medical causes were major causes of Cesarean. According to the high prevalence of caesarean section and it upward development, it seems to be essential designing and implementing of programs and interventions effectiveness including providing of Possibility of painless childbirth and education and psychological interventions, increasing of quality of natural delivery services, proper culture and prohibiting of doctors from Personal opinions and profit.