Magnetic-activated Cell Sorting Research Articles

Early Life Stress Increases Lipid Storage in Female Mice Fed a High Fat Diet via MR Activation in Adipocytes

We have previously shown that Maternal Separation and Early Weaning (MSEW), a mouse model of early life stress, exacerbates high fat diet (HF)‐induced obesity only in female offspring. Obese female MSEW mice display increased circulating and adrenal‐derived aldosterone and increased gWAT‐derived corticosterone compared with controls (C). Mineralocorticoid receptor (MR) activation has been shown to be critical in the regulation of the differentiation process of pre‐adipocytes into mature adipocytes and overall adipocyte homeostasis. The aim of this study was to determine the role of MR in the mechanism by which MSEW induces perigonadal hypertrophy in female mice fed a high fat diet (HF). MSEW and C mice were weaned onto a HF (60 % Kcal from fat). After 20 weeks, gonadal white adipose tissue (gWAT) was collected to conduct: 1) lipidomic analysis and markers of whitening, 2) collagenase digestion followed by magnetic activated cell sorting for isolation of preadipocytes for RNAseq, and 3) in vitro lipolysis assay. Another subset of mice was randomized to receive vehicle (50% Ora swift in water) or a MR blocker, spironolactone (Spiro, 100 mg/kg/day), for 2 weeks. Female MSEW mice showed increased adiposity along with reduced mitochondrial DNA density (0.81±0.09 and 1.08±0.07 mtDNA/gDNA, p<0.05 MSEW vs. C, respectively). Also, female MSEW mice displayed an increase of over 20 triacyclglycerols TAG, including a 6‐fold increase in 44:2/FA 18:2+NH4 (p<0.05 vs. C). Isolated mature adipocyte RNAseq revealed a 10‐fold downregulation of Aquaglycerolporin 3 (AQP3) in MSEW mice, a channel in adipocytes responsible for glycerol efflux (p<0.05 vs. C). Western blot analysis confirmed this reduction (0.40±0.08 and 1.0±0.14 AQP3/HSP90 p<0.05 MSEW vs. C, respectively). Spiro treatment induced a significant fat mass loss in obese MSEW females (‐3.5±0.9 and ‐1.0±0.5 delta fat mass (%BW) p<0.05 MSEW vs. C, respectively). Increased intracellular glycerol in vehicle‐treated MSEW mice was reduced to levels comparable to controls after Spiro treatment (1.08±0.2 and 1.64±0.12 mg glycerol/mg tissue, p<0.05 MSEW vs. C, respectively) while Spiro also decreased basal and stimulated released glycerol in MSEW mice (p<0.05). There were no differences in plasma glycerol between groups. It has been shown that aldosterone modulates AQP3 expression via MR signaling; however, Spiro treatment did not modify AQP3 protein expression. Overall, this data suggests that MR may play a role in adipose tissue hypertrophy as displayed by MSEW mice by preventing glycerol release in favor of triglyceride formation and storage, suggesting a role for impaired lipolysis that is independent of reduced AQP3 protein expression in adipocyte hypertrophy displayed by obese female MSEW mice.

Cell type specific isolation of primary astrocytes and microglia from adult mouse spinal cord

BackgroundAstrocytes and microglia are essential cellular elements of the CNS that are critical for normal development, function, and injury responses. Both cell types are highly pleiotropic and respond rapidly to environmental changes, making them challenging to characterize. One approach is to develop efficient isolation paradigms of distinct cell populations, allowing for characterization of their roles in distinct CNS regions and in pathological states. New methodWe have developed an efficient and reliable protocol for isolation of astrocytes and microglia from the adult mouse spinal cord, which can be easily manipulated for immediate or future analyses. This method involves (1) rapid tissue dissociation; (2) cell release after myelin debris removal; (3) magnetic-activated cell sorting; and (4) optional downstream molecular and functional analyses. ResultsHigh levels of viability and purity of the cells were confirmed after isolation. More importantly, characterization of cells verified their ability to proliferate and respond to external stimuli for potential use in downstream molecular and functional assays. Comparison with existing method(s)Long-term culture of cells isolated from neonatal animals and cell type specific isolation from the brain have been successful; however, isolation of spinal cord cells from adult mice has been challenging due to the large amount of myelin and limited size of the tissue compared to the brain. Our method allows for efficient isolation of astrocytes and microglia from spinal cord alone and includes simple modifications to allow for various downstream applications. ConclusionsThis technique will be a valuable tool to better understand the functions of astrocytes and microglia in spinal cord function and pathology.

Methionine restriction enhances the chemotherapeutic sensitivity of colorectal cancer stem cells by miR-320d/c-Myc axis.

Chemotherapy resistance of colorectal cancer stem cells (CRC-SCs) has become a major challenge in clinical treatment of cancer. Methionine restriction (MR) enhances the therapeutic effect of chemotherapeutic agents. The aim of this study was to explore the molecular pathways that MR affects the chemotherapeutic sensitivity of CRC-SCs. CD133+ and CD133- SW480 or SW620 cells were isolated by magnetic-activated cell sorting (MACS). Mouse xenograft tumor model was established by subcutaneous inoculation of CD133+ SW480. MTT assay was used to detect cell viability. Phase distribution of cell cycle was detected by flow cytometry. Western blotting was used to detect drug-resistant related protein expression. miR-320d and transcription factor c-Myc expressions were detected by qRT-PCR. The interaction between miR-320d and c-Myc was verified by luciferase assay. CD133+ SW480 and SW620 cells were more resistant to 5-fluorouracil (5-FU) than CD133- cells. In vitro and in vivo experiments showed that 5-FU and MR combined therapy further inhibited CD133+ cell activity and ATP binding cassette subfamily G member 2 (ABCG2) expression, and reduced tumor volume compared with drug administration alone. Interference with miR-320d or overexpression of c-Myc reversed the increased chemotherapeutic sensitivity of CRC-SCs induced by synergistic therapy with 5-FU and MR. miR-320d can target and regulate c-Myc. Interference with c-Myc could reverse the increase in cell viability and ABCG2 expression caused by down-regulation of miR-320d. In conclusion, the combined chemotherapy with MR can enhance the chemotherapeutic sensitivity of CRC-SCs by up-regulation of miR-320d to inhibit c-Myc expression, which lays a molecular basis for MR regulation of chemotherapeutic sensitivity of CRC-SCs.

Isolation of Mouse Primary Microglia by Magnetic-Activated Cell Sorting in Animal Models of Demyelination

Isolation of Mouse Primary Microglia by Magnetic-Activated Cell Sorting in Animal Models of Demyelination

Isolation of Mouse Primary Microglia by Magnetic-Activated Cell Sorting in Animal Models of Demyelination.

Microglia, the resident innate immune cells in the brain, are the primary responders to inflammation or injury in the central nervous system (CNS). Microglia can be divided into resting state and activated state and can rapidly change state in response to the microenvironment of the brain. Microglia will be activated under different pathological conditions and exhibit different phenotypes. In addition, there are many different subgroups of activated microglia and great heterogeneity between different subgroups. The heterogeneity mainly depends on the molecular specificity of microglia. Studies have revealed that microglia will be activated and play an important role in the pathological process of inflammatory demyelination. To better understand the characteristics of microglia in inflammatory demyelinating diseases such as multiple sclerosis and neuromyelitis optica spectrum disorder, we propose a perilesional primary microglial sorting protocol. This protocol utilizes columnar magnetic-activated cell sorting (MACS) to obtain highly purified primary microglia and preserve the molecular characteristics of microglia to investigate the potential effects of microglia in inflammatory demyelinating diseases.

Single-Cell Sequencing of Immune Cells in Human Aortic Dissection Tissue Provides Insights Into Immune Cell Heterogeneity.

BackgroundInflammation plays an important role in the progression of sporadic aortic dissection (AD). Immune cells, especially macrophages, infiltrate the aorta and secrete inflammatory cytokines and matrix metalloproteinases to cause degradation of the extracellular matrix, thereby contributing to the pathogenesis of AD. However, the cellular heterogeneity within these immune cells has not been fully characterized.MethodsWe used single-cell RNA sequencing to profile the transcriptomes of all immune cells in AD tissue and normal aorta. Using magnetic-activated cell sorting gating on CD45, we obtained a higher resolution identification of the immune cell subsets in the aorta.ResultsWe observed significant differences in the proportion of major immune cell subpopulations between AD and normal aorta tissues. Macrophages accounted for a higher percentage in the normal aorta, while the proportions of T cells, B cells and natural killer (NK) cells were all increased in AD tissues. Macrophage clusters that expanded in AD tissues originated primarily from circulating monocytes and expressed genes encoding proinflammatory cytokines and molecules involved in tissue repair. T and NK cells in AD tissues exhibited enhanced cytotoxic properties. A cluster of CD4+ T cells that had expanded in AD tissues was Th17-like and might contribute to the pathogenesis of AD. Cell–cell interaction analysis highlighted the increased communication between macrophages and T cells, which primarily regulated the costimulation of T cells.ConclusionsOur study provides a comprehensive characterization of immune cells in the dissected aorta with an emphasis on the role of macrophages and T cells. The information from our study improves our understanding of immune mechanisms in AD formation and helps to identify additional useful targets for early diagnosis or therapy of AD.

Identification, Isolation, and Characterization of Melanocyte Precursor Cells in the Human Limbal Stroma.

Given their vital role in the homeostasis of the limbal stem cell niche, limbal melanocytes have emerged as promising candidates for tissue engineering applications. This study aimed to isolate and characterize a population of melanocyte precursors in the limbal stroma, compared with melanocytes originating from the limbal epithelium, using magnetic-activated cell sorting (MACS) with positive (CD117/c-Kit microbeads) or negative (CD326/EpCAM or anti-fibroblast microbeads) selection approaches. Both approaches enabled fast and easy isolation and cultivation of pure limbal epithelial and stromal melanocyte populations, which differed in phenotype and gene expression, but exhibited similar functional properties regarding proliferative potential, pigmentation, and support of clonal growth of limbal epithelial stem/progenitor cells (LEPCs). In both melanocyte populations, limbus-specific matrix (laminin 511-E8) and soluble factors (LEPC-derived conditioned medium) stimulated melanocyte adhesion, dendrite formation, melanogenesis, and expression of genes involved in UV protection and immune regulation. The findings provided not only a novel protocol for the enrichment of pure melanocyte populations from limbal tissue applying easy-to-use MACS technology, but also identified a population of stromal melanocyte precursors, which may serve as a reservoir for the replacement of damaged epithelial melanocytes and an alternative resource for tissue engineering applications.

A Computer-Aided Diagnosis System of Fetal Nucleated Red Blood Cells With Convolutional Neural Network.

The rapid recognition of fetal nucleated red blood cells (fNRBCs) presents considerable challenges. To establish a computer-aided diagnosis system for rapid recognition of fNRBCs by convolutional neural network. We adopted density gradient centrifugation and magnetic-activated cell sorting to extract fNRBCs from umbilical cord blood samples. The cell-block method was used to embed fNRBCs for routine formalin-fixed paraffin sectioning and hematoxylin-eosin staining. Then, we proposed a convolutional neural network-based, computer-aided diagnosis system to automatically discriminate features and recognize fNRBCs. Extracting methods of interested region were used to automatically segment individual cells in cell slices. The discriminant information from cellular-level regions of interest was encoded into a feature vector. Pathologic diagnoses were also provided by the network. In total, 4760 pictures of fNRBCs from 260 cell-slides of 4 umbilical cord blood samples were collected. On the premise of 100% accuracy in the training set (3720 pictures), the sensitivity, specificity, and accuracy of cellular intelligent recognition were 96.5%, 100%, and 98.5%, respectively, in the test set (1040 pictures). We established a computer-aided diagnosis system for effective and accurate fNRBC recognition based on a convolutional neural network.

Isolation and characterization of peritoneal microvascular pericytes.

As a potential source of myofibroblasts, pericytes may play a role in human peritoneal fibrosis. The culture of primary vascular pericytes in animals has previously been reported, most of which are derived from cerebral and retinal microvasculature. Here, in the field of peritoneal dialysis, we describe a method to isolate and characterize mouse peritoneal microvascular pericytes. The mesenteric tissues of five mice were collected and digested by type II collagenase and type I DNase. After cell attachment, the culture fluid was replaced with pericyte‐conditioned medium. Pericytes with high purity (99.0%) could be isolated by enzymatic disaggregation combined with conditional culture and magnetic activated cell sorting. The primary cells were triangular or polygonal with protrusions, and confluent cell culture could be established in 3 days. The primary pericytes were positive for platelet‐derived growth factor receptor‐β, α‐smooth muscle actin, neuron‐glial antigen 2, and CD13. Moreover, they promoted formation of endothelial tubes, and pericyte–myofibroblast transition occurred after treatment with transforming growth factor‐β1. In summary, we describe here a reproducible isolation protocol for primary peritoneal pericytes, which may be a powerful tool for in vitro peritoneal fibrosis studies.

Successful in vivo Transplantation of Cultured and Enriched Testicular Germ Cells of Pre-Pubertal Bucks to Busulfan-Treated Homologous Recipients

The objective of the present study was to establish a workable approach for the production of germ cell (GC)-depleted recipient goat model using intra-testicular busulfan treatment and transplantation of cultured and enriched caprine-male GC (cmGCs) into the homologous recipients under ultrasonography (USG) guidance. The evaluation of post-transplantation colonization of donor cmGCs and restoration of the normal architecture of seminiferous tubules (ST) was performed. For this, the cmGCs of pre-pubertal male goats were isolated and enriched by differential platting for culture until the third passage. Thereafter, cells were harvested and further enriched by magnetic-activated cell sorting using rabbit-anti-CD90 antibody. After confirmation of metabolic viability (MTT-assay) and cluster-forming ability (crystal violet staining) of CD90⁺ cmGCs, the cells were labeled with a lipophilic red-fluorescent dye (PKH26) before transplanted into the recipient male goats by injection directly into the mediastinum testes under USG guidance. The colonization and repopulation of transplanted CD90⁺ cmGCs into the recipient ST was observed up to 8 weeks post-transplantation. The PKH26-labeled donor cell-derived colonies were identified in enzymatically digested ST and cryosections of recipient testes. Moreover, histochemical analyses revealed the restoration of the normal architecture of ST of recipient testis after GC transplantation. Therefore, the results suggest that the reproductive competence of infertile animals can be restored through mGC therapy and thus the methodology presented herein could be useful to obtain donor mGCs-derived functional male gametes in the recipient animal testis.

In-depth biological analysis of alteration in Plasmodium knowlesi-infected red blood cells using a noninvasive optical imaging technique

BackgroundImaging techniques are commonly used to understand disease mechanisms and their biological features in the microenvironment of the cell. Many studies have added to our understanding of the biology of the malaria parasite Plasmodium knowlesi from functional in vitro and imaging analysis using serial block-face scanning electron microscopy (SEM). However, sample fixation and metal coating during SEM analysis can alter the parasite membrane.MethodsIn this study, we used noninvasive diffraction optical tomography (DOT), also known as holotomography, to explore the morphological, biochemical, and mechanical alterations of each stage of P. knowlesi-infected red blood cells (RBCs). Each stage of the parasite was synchronized using Nycodenz and magnetic-activated cell sorting (MACS) for P. knowlesi and P. falciparum, respectively. Holotomography was applied to measure individual three-dimensional refractive index tomograms without metal coating, fixation, or additional dye agent.ResultsDistinct profiles were found on the surface area and hemoglobin content of the two parasites. The surface area of P. knowlesi-infected RBCs showed significant expansion, while P. falciparum-infected RBCs did not show any changes compared to uninfected RBCs. In terms of hemoglobin consumption, P. falciparum tended to consume hemoglobin more than P. knowlesi. The observed profile of P. knowlesi-infected RBCs generally showed similar results to other studies, proving that this technique is unbiased.ConclusionsThe observed profile of the surface area and hemoglobin content of malaria infected-RBCs can potentially be used as a diagnostic parameter to distinguish P. knowlesi and P. falciparum infection. In addition, we showed that holotomography could be used to study each Plasmodium species in greater depth, supporting strategies for the development of diagnostic and treatment strategies for malaria.Graphical

Minimizing the Ex Vivo Confounds of Cell-Isolation Techniques on Transcriptomic and Translatomic Profiles of Purified Microglia.

Modern molecular and biochemical neuroscience studies require analysis of specific cellular populations derived from brain tissue samples to disambiguate cell type-specific events. This is particularly true in the analysis of minority glial populations in the brain, such as microglia, which may be obscured in whole tissue analyses. Microglia have central functions in development, aging, and neurodegeneration and are a current focus of neuroscience research. A long-standing concern for glial biologists using in vivo models is whether cell isolation from CNS tissue could introduce ex vivo artifacts in microglia, which respond quickly to changes in the environment. Mouse microglia were purified by magnetic-activated cell sorting (MACS), as well as cytometer-based and cartridge-based fluorescence-activated cell sorting (FACS) approaches to compare and contrast performance. The Cx3cr1-NuTRAP mouse model was used to provide an endogenous fluorescent microglial marker and a microglial-specific translatome profile as a baseline comparison lacking cell isolation artifacts. All sorting methods performed similarly for microglial purity with main differences being in cell yield and time of isolation. Ex vivo activation signatures occurred principally during the initial tissue dissociation and cell preparation and not the cell sorting. The cell preparation-induced activational phenotype could be minimized by inclusion of transcriptional and translational inhibitors or non-enzymatic dissociation conducted entirely at low temperatures. These data demonstrate that a variety of microglial isolation approaches can be used, depending on experimental needs, and that inhibitor cocktails are effective at reducing cell preparation artifacts.

Cell Surface Proteins for Enrichment and In Vitro Characterization of Human Pluripotent Stem Cell-Derived Myogenic Progenitors.

Human myogenic progenitors can be derived from pluripotent stem cells (PSCs) for use in modeling natural and pathological myogenesis, as well as treating muscle diseases. Transgene-free methods of deriving myogenic progenitors from different PSC lines often produce mixed populations that are heterogeneous in myogenic differentiation potential, yet detailed and accurate characterization of human PSC-derived myogenic progenitors remains elusive in the field. The isolation and purification of human PSC-derived myogenic progenitors is thus an important methodological consideration when we investigate the properties and behaviors of these cells in culture. We previously reported a transgene-free, serum-free floating sphere culture method for the derivation of myogenic progenitors from human PSCs. In this study, we first performed comprehensive cell surface protein profiling of the sphere culture cells through the screening of 255 antibodies. Next, we used magnetic activated cell sorting and enriched the cells according to the expression of specific surface markers. The ability of muscle differentiation in the resulting cells was characterized by immunofluorescent labeling and quantification of positively stained cells. Our results revealed that myotube-forming cells resided in the differentiated cultures of CD29+, CD56+, CD271+, and CD15– fractions, while thick and multinucleated myotubes were identified in the differentiated cultures from CD9+ and CD146+ fractions. We found that PAX7 localization to the nucleus correlates with myotube-forming ability in these sorted populations. We also demonstrated that cells in unsorted, CD271+, and CD15– fractions responded differently to cryopreservation and prolonged culture expansion. Lastly, we showed that CD271 expression is essential for terminal differentiation of human PSC-derived myogenic progenitors. Taken together, these cell surface proteins are not only useful markers to identify unique cellular populations in human PSC-derived myogenic progenitors but also functionally important molecules that can provide valuable insight into human myogenesis.

Tongue Muscle for the Analysis of Head Muscle Regeneration Dynamics

Tongue muscle damage impairs speaking and eating, thereby degrading overall health and quality of life. Skeletal muscles of the body are diverse in embryonic origin, anatomic location, and gene expression profiles. Responses to disease, atrophy, aging, or drugs vary among different muscles. Currently, most muscle studies are focused on limb muscles and the tongue is neglected. The regenerative ability of tongue muscle remains unknown, and thus there is need for tongue muscle research models. Here, we present a comprehensive characterization of the spatiotemporal dynamics in a mouse model of tongue muscle regeneration and establish a method for the isolation of primary tongue-derived satellite cells. We compare and contrast our observations with the tibialis anterior (TA) limb muscle. Acute injury was induced by intramuscular injection of cardiotoxin, a cytolytic agent, and examined at multiple timepoints. Initially, necrotic myofibers with fragmented sarcoplasm became infiltrated with inflammatory cells. Concomitantly, satellite cells expanded rapidly. Seven days postinjury, regenerated myofibers with centralized nuclei appeared. Full regeneration, as well as an absence of fibrosis, was evident 21 d postinjury. Primary tongue-derived satellite cells were isolated by enzymatic separation of tongue epithelium from mesenchyme followed by magnetic-activated cell sorting. We observed that tongue displays an efficient regenerative response similar to TA but with slightly faster kinetics. In vitro, tongue-derived satellite cells differentiated robustly into mature myotubes with spontaneous contractile behavior and myogenic marker expression. Comparison of gene expression signatures between tongue and TA-derived satellite cells revealed differences in the expression of positional-identity genes, including the HOX family. In conclusion, we have established a model for tongue regeneration useful for investigations of orofacial muscle biology. Furthermore, we showed that tongue is a viable source of satellite cells with unique properties and inherited positional memory.

Two modified density gradient centrifugation methods facilitate the isolation of mouse Leydig cells

Preparation of sufficient mouse Leydig cells (LCs) with high purity is a prerequisite for investigations of the biological/pathological functions of LCs in mouse models. Density gradient centrifugation based on discontinuous Percoll gradients is an effective method (defined as regular method) for LC isolation. In this study, we developed two modified methods for LC isolation and compared their performance with that of the regular method. Modified method 1 integrated the crude LCs into the 50% Percoll solution before centrifugation. Modified method 2 sequentially used 50 and 60% Percoll solutions to isolate LCs. The purity of LCs was approximately 88.4, 91.3, and 79.7% derived from the regular, modified 1, and modified 2 methods, respectively. The yields of LCs in the same respective order were approximately 1.7 × 105, 3.9 × 105, and 11.9 × 105 cells per 108 interstitial cells input. Modified method 1 attained higher purity and yields than those of the regular method. Although the purity of LCs was relatively low for modified method 2, it could be used before further purification by, for example, fluorescence-activated or magnetic-activated cell sorting, owing to its simplicity and high yields. Therefore, our study provided alternative methods to facilitate LC isolation in mice.

Telomerase inhibition on acute myeloid leukemia stem cell induced apoptosis with both intrinsic and extrinsic pathways

AimsAcute Myeloid Leukemia (AML) is an invasive and lethal blood cancer caused by a rare population of Leukemia Stem Cells (LSCs). Telomerase activation is a limitless self-renewal process in LSCs. Apart from telomerase role in telomere lengthening, telomerase (especially hTERT subunit) inhibits intrinsic-, extrinsic-, and p53- mediated apoptosis pathways. In this study, the effect of Telomerase Inhibition (TI) on intrinsic-, extrinsic-, p53-mediated apoptosis, and DNMT3a and TET epigenetic markers in stem (CD34+) and differentiated (CD34−) AML cells is evaluated. Main methodsHigh-purity CD34+ (primary AML and KG-1a) cells were enriched using the Magnetic-Activated Cell Sorting (MACS) system. CD34+ and CD34− (primary AML and KG-1a) cells were treated with BIBR1532 and then, MTT assay, Annexin V/7AAD, Ki-67 assay, Telomere Length (TL) measurement, and transcriptional alterations of p53, hTERT, TET2, DNMT3a were analyzed. Finally, apoptosis-related genes and proteins were studied. Key findingsTI with the IC50 values of 83.5, 33.2, 54.3, and 24.6 μM in CD34+ and CD34− (primary AML and KG-1a) cells significantly inhibited cell proliferation and induced apoptosis. However, TI had no significant effect on TL. The results also suggested TI induced intrinsic-, extrinsic-, and p53-mediated apoptosis. It was shown that the expression levels of DNMT3a and TET2 epigenetic markers were highly increased following TI. SignificanceIn total, it was revealed that TI induced apoptosis through intrinsic, extrinsic, and p53 pathways and increased the expression of DNMT3a and TET2 epigenetic markers.

Comparison of single layer centrifugation and magnetic activated cell sorting for selecting viable boar spermatozoa after thawing

Sperm selection techniques, such as magnetic activated cell sorting (MACS) and colloid centrifugation, are reported to select good quality spermatozoa from semen samples of various species. Although the sperm quality of fresh boar semen is usually good, cryopreservation has a negative effect on parameters such as plasma membrane integrity and mitochondrial activity. Therefore, the objective of the present study was to determine whether MACS or centrifugation through a single layer of colloid (Single Layer Centrifugation, SLC) would be beneficial in enriching thawed boar sperm samples for viable spermatozoa with active mitochondria and good chromatin integrity. Frozen samples from three boars, three ejaculates per boar, were thawed and split. One part was selected by MACS, one was prepared by SLC, and the remainder served as the control. Controls and the selected sperm samples were evaluated for sperm quality (plasma membrane integrity, chromatin integrity, mitochondrial membrane potential and production of reactive oxygen species). Although several aspects of sperm quality were improved in the SLC-selected sperm samples compared to control, the flow-through MACS samples were only improved in having a lower proportion of spermatozoa with immature chromatin (Hi green fluorescence) compared to the labeled control. Sperm quality in the SLC samples was better than in the flow-through samples from MACS. Therefore, despite promising reports of the use of MACS for selecting good quality spermatozoa from semen in other species, the method was not useful for improving sperm quality in the thawed boar sperm samples in this experiment.

A critical review of in vitro research methodologies used to study mineralization in human dental pulp cell cultures.

BackgroundThe pulp contains a resident population of stem cells which can be stimulated to differentiate in order to repair the tooth by generating a mineralized extracellular matrix. Over recent decades there has been considerable interest in utilizing in vitro cell culture models to study dentinogenesis, with the aim of developing regenerative endodontic procedures, particularly where some vital pulp tissue remains.ObjectivesThe purpose of this review is to provide a structured oversight of in vitro research methodologies which have been used to study human pulp mineralization processes.MethodThe literature was screened in the PubMed database up to March 2021 to identify manuscripts reporting the use of human dental pulp cells to study mineralization. The dataset identified 343 publications initially which were further screened and consequently 166 studies were identified and it was methodologically mined for information on: i) study purpose, ii) source and characterization of cells, iii) mineralizing supplements and concentrations, and iv) assays and markers used to characterize mineralization and differentiation, and the data was used to write this narrative review.ResultsMost published studies aimed at characterizing new biological stimulants for mineralization as well as determining the effect of scaffolds and dental (bio)materials. In general, pulp cells were isolated by enzymatic digestion, although the pulp explant technique was also common. For enzymatic digestion, a range of enzymes and concentrations were utilized, although collagenase type I and dispase were the most frequent. Isolated cells were not routinely characterized using either fluorescence‐activated cell sorting (FACS) and magnetic‐activated cell sorting (MACS) approaches and there was little consistency in terming cultures as dental pulp cells or dental pulp stem cells. A combination of media supplements, at a range of concentrations, of dexamethasone, ascorbic acid and beta‐glycerophosphate, were frequently applied as the basis for the experimental conditions. Alizarin Red S (ARS) staining was the method of choice for assessment of mineralization at 21‐days. Alkaline phosphatase assay was relatively frequently applied, solely or in combination with ARS staining. Further assessment of differentiation status was performed using transcript or protein markers, with dentine sialophosphoprotein (DSPP), osteocalcin and dentine matrix protein‐1 (DMP ‐1), the most frequent.DiscussionWhile this review highlights variability among experimental approaches, it does however identify a consensus experimental approach.ConclusionStandardization of experimental conditions and sustained research will significantly benefit endodontic patient outcomes in the future.

Effects of bone marrow-derived mesenchymal stem cells exposed to endocrine-disrupting chemicals on the differentiation of umbilical cord blood hematopoietic stem cells.

Endocrine-disrupting chemicals (EDCs), a class of peripheral toxic substances, can cause many environmental and clinical side effects, particularly on the human body's endocrine system. Bisphenol A (BPA) and diethylhexyl phthalate (DEHP) are two well-known EDCs in the medicine industry. However, there are no comprehensive studies on their effects on hematopoiesis. Hence, this study aimed to investigate the effect of these two aforementioned substances on the clonogenic capacity of umbilical cord blood hematopoietic stem cells (CB-HSCs). The HSCs which express CD34 + were isolated from umbilical cord blood by the magnetic-activated cell sorting (MACS) system. To investigate the effects of different optimized concentrations of BPA and DEHP, CB-CD34+ HSCs were exposed to EDCs in semisolid medium. For evaluation of coexposures, CB-CD34+ HSCs were cocultured with bone marrow-derived mesenchymal stem cells (BM-MSCs) in the presence of BPA and DEHP. Finally, the number and types of colonies were evaluated after 14days. Statistical analysis was performed by GraphPad Prism through ANOVA. CB-HSC treated by BPA and DEHP showed a lower absolute colony count than the control group (P < 0.05). Decrease in clonogenic potential of HSCs was more significant in coculture condition by MSCs. In particular, there was a significant decrease in the BFU-E colonies in comedicated-derived fractions (P < 0.0001). In the presence of EDCs such as BPA and DEHP, the patterns of differentiation in CD34+ CB-HSCs changed from suppressed erythroid differentiation toward stimulated myelogenesis pathways.

Accelerated embryonic stem cell screening with a highly efficient genotyping pipeline.

Gene targeting in mouse ES cells replaces or modifies genes of interest; conditional alleles, reporter knock-ins, and amino acid changes are common examples of how gene targeting is used. For example, enhanced green fluorescent protein or Cre recombinase is placed under the control of endogenous genes to define promoter expression patterns. The most important step in the process is to demonstrate that a gene targeting vector is correctly integrated in the genome at the desired chromosomal location. The rapid identification of correctly targeted ES cell clones is facilitated by proper targeting vector construction, rapid screening procedures, and advances in cell culture. Here, we optimized and functionally linked magnetic activated cell sorting (MACS) technology as well as multiplex droplet digital PCR (ddPCR) to our ES cell screening process to achieve a greater than 60% assurance that ES clones are correctly targeted. In a further refinement of the process, drug selection cassettes are removed from ES cells with adenovirus technology. We describe this improved workflow and illustrate the reduction in time between therapeutic target identification and experimental validation. In sum, we describe a novel and effective implementation of ddPCR, multiMACS, and adenovirus recombinase into a streamlined screening workflow that significantly reduces timelines for gene targeting in mouse ES cells.