Basic Cell Types Research Articles

Numerical simulation of skin formation: epidermal stem cells and undulation of the basal layer

The basal layer at the base of the epidermis produces new epidermal cells once a week and plays an important role in skin formation. Interestingly, the basal layer undulates, and the amplitude of this undulation is dependent on age or disease. However, the mechanisms driving this phenomenon have not been well studied. This work simulated the skin formation process using an original method to understand the mechanism of the undulation formation in the basal layer. The basal layer has cells with both short and long cell cycles, but only the former has been examined in previous studies. Accordingly, we more accurately simulated the skin formation process by including cells with a long cell cycle and observed undulation of the basal layer. Based on our findings, we propose that the basal layer undulates due to the interaction between two types of basal layer cells.

Analysis of Clinical Characteristics of 35 Cases of Pulmonary Sclerosing Pneumocytoma

背景与目的硬化性肺泡细胞瘤（pulmonary sclerosing pneumocytom, PSP）是临床上相对少见的良性肺肿瘤，多发于中年女性，无典型的临床表现及影像学表现。PSP包括表面立方上皮细胞和圆形间质细胞2种基本细胞类型，有4种组织学类型（出血性、硬化性、实性和乳头状），可发生远处转移，但生长缓慢，术前病理检查易误诊。本研究通过探讨该病的临床特征，旨在提高临床医师对PSP的认识。方法回顾性分析我院2011年1月-2019年12月收治的35例经病理学检查确诊的PSP临床病例资料。结果本研究共35例患者，男性12例，女性23例，平均年龄51岁。7例因体检或常规行胸部计算机断层扫描（computed tomography, CT）偶然发现，28例因咳嗽、咳痰、咯血、胸痛等症状就诊。影像学主要表现为肺部孤立的、边界清楚的圆形或类圆形结节、肿块影。本组有12例行经皮肺穿刺组织病理活检术，仅有7例诊断为PSP。本组共28例行手术治疗，24例术中行快速冷冻病理切片检查，仅5例提示PSP。术后病理检查结果1例诊断肺角化型鳞癌伴局部PSP，其余均诊断为PSP。本组手术和非手术患者出院后随访1年-8年，总体恢复好，复查胸部CT无复发和转移。结论PSP为临床上少见的肺部良性肿瘤，多发于中年女性，临床表现、影像学检查均缺乏特异性，经皮肺穿刺病理检查及术中快速冰冻病理切片容易误诊，多数病例最终需术后病理检查才能明确诊断。

Histological and micrometrical exploration of corpus Luteum in cyclic Nellore sheep

Ovaries from twenty two apparently healthy, non-pregnant and cyclic Nellore sheep was taken with the aim to explore histological and micrometrical aspects of the corpus luteum in ovary of adult Nellore sheep. The sections were cut at 5-6µ thick and histological procedures were carried out. From capsule, various trabeculae descend into the substance of corpus luteum. Thickness of the trabeculae which descends from the capsule was almost equal in thickness to that of capsule at the periphery and tapers towards the centre. The capsule mainly comprised of collagen and reticular fibres. The occurrence of two fully developed corpora lutea in the same ovary was also observed. On the basis of shape and the size, three basic types of lutein cells were observed: large (16.38-28.17µm), small (7.95-27.06µm) and spindle shaped (15.73-29.57µm) cells. Moderate PAS reaction was seen in Capsule, Trabeculae and mild reaction was seen in luteal cells of corpus luteum.

Organoid cultures from normal and cancer-prone human breast tissues preserve complex epithelial lineages

Recently, organoid technology has been used to generate a large repository of breast cancer organoids. Here we present an extensive evaluation of the ability of organoid culture technology to preserve complex stem/progenitor and differentiated cell types via long-term propagation of normal human mammary tissues. Basal/stem and luminal progenitor cells can differentiate in culture to generate mature basal and luminal cell types, including ER+ cells that have been challenging to maintain in culture. Cells associated with increased cancer risk can also be propagated. Single-cell analyses of matched organoid cultures and native tissues by mass cytometry for 38 markers provide a higher resolution representation of the multiple mammary epithelial cell types in the organoids, and demonstrate that protein expression patterns of the tissue of origin can be preserved in culture. These studies indicate that organoid cultures provide a valuable platform for studies of mammary differentiation, transformation, and breast cancer risk.

Differences in proteomic profile between two haemocyte types, granulocytes and hyalinocytes, of the flat oyster Ostrea edulis

Haemocytes play a dominant role in shellfish immunity, being considered the main defence effector cells in molluscs. These cells are known to be responsible for many functions, including chemotaxis, cellular recognition, attachment, aggregation, shell repair and nutrient transport and digestion. There are two basic cell types of bivalve haemocytes morphologically distinguishable, hyalinocytes and granulocytes; however, functional differences and specific abilities are poorly understood: granulocytes are believed to be more efficient in killing microorganisms, while hyalinocytes are thought to be more specialised in clotting and wound healing. A proteomic approach was implemented to find qualitative differences in the protein profile between granulocytes and hyalinocytes of the European flat oyster, Ostrea edulis, as a way to evaluate functional differences. Oyster haemolymph cells were differentially separated by Percoll® density gradient centrifugation. Granulocyte and hyalinocyte proteins were separated by 2D-PAGE and their protein profiles were analysed and compared with PD Quest software; the protein spots exclusive for each haemocyte type were excised from gels and analysed by MALDI-TOF/TOF with a combination of mass spectrometry (MS) and MS/MS for sequencing and protein identification. A total of 34 proteins were identified, 20 unique to granulocytes and 14 to hyalinocytes. The results suggested differences between the haemocyte types in signal transduction, apoptosis, oxidation reduction processes, cytoskeleton, phagocytosis and pathogen recognition. These results contribute to identify differential roles of each haemocyte type and to better understand the oyster immunity mechanisms, which should help to fight oyster diseases.

Cell lineage-specific transcriptome analysis for interpreting cell fate specification of proembryos

In Arabidopsis, a zygote undergoes asymmetrical cell division that establishes the first two distinct cell types of early proembryos, apical and basal cells. However, the genome-wide transcriptional activities that guide divergence of apical and basal cell development remain unknown. Here, we present a comprehensive transcriptome analysis of apical and basal cell lineages, uncovering distinct molecular pathways during cell lineage specification. Selective deletion of inherited transcripts and specific de novo transcription contribute to the establishment of cell lineage-specific pathways for cell fate specification. Embryo-related pathways have been specifically activated in apical cell lineage since 1-cell embryo stage, but quick transcriptome remodeling toward suspensor-specific pathways are found in basal cell lineage. Furthermore, long noncoding RNAs and alternative splicing isoforms may be involved in cell lineage specification. This work also provides a valuable lineage-specific transcriptome resource to elucidate the molecular pathways for divergence of apical and basal cell lineages at genome-wide scale.

Spatiotemporal single-cell analysis of gene expression in the mouse suprachiasmatic nucleus.

Mammalian circadian behaviors are orchestrated by the suprachiasmatic nucleus (SCN) in the ventral hypothalamus, but the number of SCN cell types and their functional roles remain unclear. We have used single-cell RNA-sequencing to identify the basic cell types in the mouse SCN and to characterize their circadian and light-induced gene expression patterns. We identified eight major cell types, with each type displaying a specific pattern of circadian gene expression. Five SCN neuronal subtypes, each with specific combinations of markers, differ in their spatial distribution, circadian rhythmicity and light responsiveness. Through a complete three-dimensional reconstruction of the mouse SCN at single-cell resolution, we obtained a standardized SCN atlas containing the spatial distribution of these subtypes and gene expression. Furthermore, we observed heterogeneous circadian gene expression between SCN neuron subtypes. Such a spatiotemporal pattern of gene regulation within the SCN may have an important function in the circadian pacemaker.

Osteoarthritis from evolutionary and mechanistic perspectives.

Developmental osteogenesis and the pathologies associated with tissues that normally are mineralized are active areas of research. All of the basic cell types of skeletal tissue evolved in early aquatic vertebrates. Their characteristics, transcription factors, and signaling pathways have been conserved, even as they adapted to the challenge imposed by gravity in the transition to terrestrial existence. The response to excess mechanical stress (among other factors) can be expressed in the pathologic phenotype described as osteoarthritis (OA). OA is mediated by epigenetic modification of the same conserved developmental gene networks, rather than by gene mutations or new chemical signaling pathways. Thus, these responses have their evolutionary roots in morphogenesis. Epigenetic channeling and heterochrony, orchestrated primarily by microRNAs, maintain the sequence of these responses, while allowing variation in their timing that depends at least partly on the life history of the individual.

Finite Element Analysis of a Lightweight Milling Cutter for Metal Additive Manufacturing

Previous work has proposed a process for implementing a lattice structure into a milling cutter body based on clustering in the milling cutter with modified main dimensions of a BCC cubic lattice structure cell. A finite element analysis model has been created to predict the strain and deformation in the struts of the lattice. The prediction made according to static loads demonstrates that the concept of a lightweight cutter meets the strength requirements, though its stiffness does not reach the fully-filled version. The methodologies for creating the FE model are described in this paper. HyperWorks with OptiStruct were used for these analyses. Local stiffness could be improved by varying the strut diameter or using a different type of basic cell for the lattice structure in problematic locations, especially in the area of the connection between the shell of the cutter and the lattice structures.

Abstract 2156: Quantifying cell subsets and heterogeneity in living cultures using real time live-cell analysis

Abstract Considerable heterogeneity exists in the properties and activity of individual cells, even in the simplest cell system. This arises from fundamental differences in the basic cell types present, genetic or epigenetic variations, the stage of cell cycle or differentiation, and the impact of each cell’s unique and dynamic local microenvironment. Such heterogeneity is mirrored by the diversity of pharmacological response at the cellular level, where even seemingly identical cells may respond differently and at different times to drug treatments and perturbagens. Accordingly, analysis at the cell-by-cell level promises valuable and additional biological insight beyond which whole population measures may deliver. Here, we describe new, enabling and industrial-scale, live-cell analysis solutions for quantifying the phenotypic biology of cell subsets in heterogeneous cultures. Time-lapse images of cultured cancer and immune cells in 96-well microplates were automatically collected using an IncuCyte S3 live analyzer (Essen Bioscience). Using new segmentation algorithms, the boundaries of individual cells (typically 300-1000 per image) were identified in each image of the sequence. Parameters and features were extracted from single cells, such as cell area, eccentricity and fluorescence (e.g. with cell labels, cytotoxicity and apoptosis probes). Populations of cells could be identified and classified over time using custom ‘flow cytometry’-like visualisation and classification tools. Using this new approach, we demonstrate cell-by-cell analysis for a range of different primary and immortalised, adherent and non-adherent, living cells for up to 7 days in culture (e.g. Jurkat, A549, human PBMCs). This was coupled with a novel live-cell, fluorescent antibody-based labeling strategy (IncuCyte FabFluor-488) to probe for specific subsets within the cultures. Example data generated in PBMCs during T cell activation (anti-CD3/IL-2, 10 ng/mL) demonstrates the change in cell shape from small, spherical cells (average area 81 ± 0.5 µm2, eccentricity 0.57 ± 0.002) to larger, flatter cells (117 ± 4 µm2, 0.69 ± 0.004) over 120 h. With the addition of FabFluor-488-CD71, it was possible to show an associated, temporal increase in CD71 expression within the activated T cell subset (75 ± 1% of large cells were CD71 positive compared to 12 ± 1% of smaller cells at 48 h, increasing to >90% in the larger cells by 120 h). Other example data sets for subset analysis of proliferation, cell death and cell cycle measurements as well as immuno-phenotyping will be shared to illustrate the value of this approach. Citation Format: Nicola Bevan, Tim Jackson, Clare Szybut, Lauren Kelsey, Hinnah Campwala, Tim Dale, Nicholas Dana, Nevine Holtz, Eric Endsley, Dan Appledorn, Cicely Schramm, Laura Skerlos, Richard Lister, Derek J. Trezise. Quantifying cell subsets and heterogeneity in living cultures using real time live-cell analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2156.

Разнообразие клеточных типов у гаплотипа H4 Placozoa sp.

Эволюционная ветвь Пластинчатых (Placozoa) имеет большое значение для понимания происхождения и эволюции Metazoa. Представители типа Placozoa обладают простым строением тела, однако полное отсутствие органов, нервной системы и мышечных клеток резко контрастирует с достаточно сложными поведенческими реакциями, в том числе динамическими изменениями формы тела. Известно 19 гаплотипов Placozoa, включающих два вида — Trichoplax adhaerens (H1) и Hoilungia hongkongensis (H13) — и пока ещё малоисследованные штаммы, обозначаемые как H2–H19 Placozoa sp. Хотя все Placozoa имеют похожий фенотип (пластинчатую дископодобную форму тела), анализ клеточной организации был сделан только для H1 (Trichoplax adhaerens) с идентификацией шести типов клеток. В этой работе мы, используя конфокальную и электронную микроскопию, исследовали организацию штамма H4, который близок к новому роду — Hoilungia. У H4 обнаружены все шесть основных типов клеток, идентифицированных ранее у H1. Между тем мы выявили у штамма H4 большее разнообразие клеток по форме, плотности и, впервые, по мембранному потенциалу митохондрий, чем ранее было описано для H1. Это позволяет нам подчеркнуть важность объединения методов молекулярно-генетических исследований и микроскопии для уточнения клеточной систематики, включая параметры митохондриальной активности для классификации клеток и их состояний. Сравнительно-эволюционное изучение клеточных типов у разных экологических групп Placozoa и их сопоставление с функциями расширяют понимание того, как относительно простой организм формирует сложное поведение и как типы клеток эволюционируют.

Morphological and immunohistochemical characteristics of the equine corneal epithelium.

ObjectiveThe morphology of the corneal epithelium in two age groups of horses is described. Distribution patterns of proliferation‐, differentiation‐, stem cell‐associated markers and cell junction proteins were assessed.MethodsCorneal samples from 12 horses (six foals and six adult horses) were analyzed after H&E staining and immunohistochemistry using the following antibodies: E‐cadherin, β‐catenin, Connexin 43 (Cx43), tight junction protein 1 (TJP1), cytokeratin (CK) 14, CK 19, CK 3, CK 10, vimentin, Ki67, p63, nerve growth factor (NGF), ABCG2, and epithelial growth factor receptor. Semiquantitative analysis of crypt, limbal, peripheral, and central zone was performed. Semithin and ultrathin sections were used for ultrastructural evaluation of the epithelium.ResultsThe height of the epithelium varied between age groups and crypts were consistently present. In the peripheral and central epithelium, three types of basal cells resembling a pseudostratified epithelium were characterized. Potential stem cell markers (CK 14, p63, NGF, and ABCG2) were present in all zones with decreasing frequency toward the center. Cornea‐specific differentiation marker CK 3 was not expressed in the most basal cell layer of the limbal epithelium. E‐cadherin, β‐catenin, and Cx43 revealed a similar apico‐lateral signal pattern throughout the entire epithelium; only TJP1 was additionally seen at the basal surface.ConclusionsThis study presents a systematic semiquantitative evaluation of the equine corneal epithelium, showing the presence of crypts as potential stem cell niche with CK 14, p63, NGF, and ABCG2 as relevant markers for cells with regenerative capacity. The pseudostratified arrangement of the basal layer was a unique finding.

Abstract 989: Organoid cultures from normal and cancer-prone human breast tissues preserve complex epithelial lineages and can form chimeric mammary glands in vivo

Abstract Use of cell culture models to investigate the development of cancer associated with familial breast cancer syndromes is challenging because many culture methodologies do not maintain all of the lineages that are present in vivo, particularly the progenitor cells that may be the specific cancer cell-of-origin. We evaluated the ability of organoid culture technology to preserve stem/progenitor and differentiated cell types via long-term propagation of normal human mammary tissues. Tissue samples were obtained from elective reduction mammoplasties or from prophylactic mastectomies for cancer prevention, and were histologically normal. These were grown using conditions similar to organoid cultures for other epithelial cell types, as has been recently described (Sachs et al., Cell 2018). We found that basal stem and luminal progenitor cells could be cultured long-term, and differentiated in culture to generate mature basal and luminal cell types. Analysis of matched organoid cultures and native tissues by mass cytometry (CyTOF) for 38 markers at single-cell resolution confirmed the presence of multiple mammary epithelial cell types in the organoids, and demonstrated that protein expression patterns of the tissue of origin were largely preserved in culture. In addition, we generated a panel of over 40 mammary organoids derived from patients harboring inherited mutations in the cancer predisposition gene BRCA1 and from unaffected controls. Despite interindividual variability, an expansion in luminal progenitor populations associated with BRCA1 mutation could be detected in cultured organoids. Human mammary organoids heterozygous for BRCA1 could be engrafted into the murine mammary gland, resulting in mixed ductal and acinar structures. These studies indicate that this new model system is well suited for studies of aberrant phenotypes associated with BRCA1 mutation and approaches to prevent cancer development in these genetically predisposed tissues. Citation Format: Jennifer M. Rosenbluth, Ronald Schackmann, Carman Li, Norman Sachs, Deborah Dillon, Andrea Richardson, Jane Brock, Judy Garber, Gary Kenneth Gray, Jason Zoeller, Mackenzie Boedicker, Hendrick Johannes Kuiken, Hans Clevers, Joan Brugge. Organoid cultures from normal and cancer-prone human breast tissues preserve complex epithelial lineages and can form chimeric mammary glands in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 989.

High Time for Hair Cells: An Introduction to the Symposium on Sensory Hair Cells.

Sensory hair cells are highly specialized cells that form the basis for our senses of hearing, orientation to gravity, and perception of linear acceleration (head translation in space) and angular acceleration (head rotation). In many species of fish and aquatic amphibians, hair cells mediate perception of water movement through the lateral line system, and electroreceptors derived from hair cell precursors mediate electric field detection. In tunicates, cells of the mechanosensory coronal organ on the incurrent siphon meet the structural, functional, and developmental criteria to be described as hair cells, and they function to deflect large particles from entering the animal. The past two decades have witnessed significant breakthroughs in our understanding of hair cell biology and how their specialized structures influence their functions. This symposium combines the approaches of developmental biology, evolutionary biology, and physiology to share the gains of recent research in understanding hair cell function in different model systems. We brought together researchers working on sensory hair cells in organisms spanning the chordates in order to examine the depth and breadth of hair cell evolution. It is clear that these specialized cells serve a range of functions in different animals, due to evolutionary tinkering with a basic specialized cell type. This collection of papers will serve to mark the progress that has been made in this field and also stimulate the next wave of progress in this exciting field.

Strategies for Preparing Graphene Liquid Cells for Transmission Electron Microscopy.

A graphene liquid cell for transmission electron microscopy (TEM) uses one or two graphene sheets to separate the liquid from the vacuum in the microscope. In principle, graphene is an excellent material for such an application because it allows the highest possible spatial resolution, provides a flexible covering foil, and effectively protects the liquid from evaporating. Examples in open literature have demonstrated atomic-resolution TEM using small liquid pockets and the coverage of whole biological cells with graphene sheets. A total of three different basic types of liquid cells are discerned: (i) one graphene sheet is used to cover a liquid sample supported by a thin membrane of another material (for example, silicon nitride, SiN), (ii) two graphene sheets pressed together leaving liquid pockets with graphene at both sides, and (iii) a spacer material with liquid pockets covered at both sides by graphene. A total of four different process flows are available for liquid cell assembly, but there is not yet a consensus on the best routes, and a number of variations exist. The key step is the transfer of graphene to a liquid sample, which is complicated by practical issues that arise from imperfections in the graphene sheets, such as cracks. This review provides an overview of these different approaches to assembling graphene liquid cells and discusses the main obstacles and ideas to overcome them with the prospect of developing the nanoscale technology needed for graphene liquid cells so that they become available on a routine basis for electron microscopy in liquid. It also provides guidance in selecting the appropriate type of graphene liquid cell and the best assembly method for a specific experiment.

EGCG promotes cell growth inhibition and reprograms mesenchymal‐epithelial transition by restoring CCN5/WISP2 in triple negative breast cancer cells in vitro and in vivo

Background and ObjectiveCCN5/WISP‐2, a matricellular secretory protein that is localized in both cytoplasm and nucleus, is mainly expressed in luminal cells rather than basal cell types in breast cancer tumors. Endogenous CCN5 plays critical role in promoting growth arrest and reprograming Mesenchymal to Epithelial Transition(MET), inhibition of migration and invasion, overall inducing the invasive to non‐invasive phenotypes. Thus, we hypothesize that targeting endogenous CCN5 restoration in Triple‐negative‐breast cancer (TNBC) cells could be an ideal strategy to prevent the progression of TNBC. To test the hypothesis, we set out to identify a molecule that has the capability to restore CCN5 in TNBC cells. Here we report that CCN5, which is normally absent in TNBC cells can be restored by a common dietary supplement epigallocatechin‐3‐gallate (EGCG), an ester of epigallocatechin and gallic acid, and is a type of catechin, to promote growth arrest and reverse EMT.MethodsEffect of EGCG on breast cancer cells were characterized by in vitro protein and gene expression profilings, cytotoxic assays, colony formation assays, migration assays, anchorage independent growth assays. In vivo effect of EGCG on tumorigenesis was investigated in xenograft model of immunosuppressive mice.Result and ConclusionEGCG treatment in breast cancer cells significantly elevated and restored CCN5 expression in TNBC cells along with inhibition of cell proliferation, migration and colony formation and induction of apoptosis. Reprogramming of mesenchymal to epithelial transition(MET) was also observed in EGCG‐treated TNBC cells. Oral administration of EGCG resulted in drastic inhibition of tumor growth and propagation in immunosuppressive mouse xenografts of MDA‐MB‐231 cells, along with restoration of CCN5 expression. Altogether, these studies clearly indicate that EGCG is an ideal molecule to restore CCN5 in TNBC cells in preventing the TNBC growth, progression and possibly make these cells susceptible to anti‐estrogen treatment, as restoration of CCN5 causes estrogen receptor(ER)‐α in TNBC cells. Moreover, it is reasonable to speculate that the CCN5 pathways probably play an important part in the anti‐tumorigenic role of EGCG in TNBC cells.Support or Funding InformationSupported by Midwest Biomedical Research Foundation and VA Merit Grant.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Synthetic PEG Hydrogel for Engineering the Environment of Ovarian Follicles.

The functional unit within the ovary is the ovarian follicle, which is also a morphological unit composed of three basic cell types: the oocyte, granulosa, and theca cells. Similar to human ovarian follicles, mouse follicles can be isolated from their ovarian environment and cultured in vitro to study folliculogenesis, or follicle development for days or weeks. Over the course of the last decade, follicle culture in a three-dimensional (3D) environment exponentially improved the outcomes of in vitro folliculogenesis. Follicle culture in 3D environments preserves follicle architecture and promotes the cross talk between cells in the follicle. Hydrogels, such as polyethylene glycol (PEG), have been used for various physiological systems for regenerative purposes because they provide a 3D environment similar to soft tissues, allow diffusion of nutrients, and can be readily modified to present biological signals, including cell adhesion ligands and proteolytic degradation facilitated by enzymes secreted by the encapsulated cells. This chapter outlines the application of PEG hydrogels to the follicle culture, including the procedures to isolate, encapsulate, and culture mouse ovarian follicles. The tunable properties of PEG hydrogels support co-encapsulation of ovarian follicles with somatic cells, which further promote follicle survival and growth in vitro through paracrine and juxtacrine interactions.

Anatomical Alterations in Plant Tissues Induced by Plant-Parasitic Nematodes.

Plant-parasitic nematodes (PPNs) interact with plants in different ways, for example, through subtle feeding behavior, migrating destructively through infected tissues, or acting as virus-vectors for nepoviruses. They are all obligate biotrophic parasites as they derive their nutrients from living cells which they modify using pharyngeal gland secretions prior to food ingestion. Some of them can also shield themselves against plant defenses to sustain a relatively long lasting interaction while feeding. This paper is centered on cell types or organs that are newly induced in plants during PPN parasitism, including recent approaches to their study based on molecular biology combined with cell biology-histopathology. This issue has already been reviewed extensively for major PPNs (i.e., root-knot or cyst nematodes), but not for other genera (viz. Nacobbus aberrans, Rotylenchulus spp.). PPNs have evolved with plants and this co-evolution process has allowed the induction of new types of plant cells necessary for their parasitism. There are four basic types of feeding cells: (i) non-hypertrophied nurse cells; (ii) single giant cells; (iii) syncytia; and (iv) coenocytes. Variations in the structure of these cells within each group are also present between some genera depending on the nematode species viz. Meloidogyne or Rotylenchulus. This variability of feeding sites may be related in some way to PPN life style (migratory ectoparasites, sedentary ectoparasites, migratory ecto-endoparasites, migratory endoparasites, or sedentary endoparasites). Apart from their co-evolution with plants, the response of plant cells and roots are closely related to feeding behavior, the anatomy of the nematode (mainly stylet size, which could reach different types of cells in the plant), and the secretory fluids produced in the pharyngeal glands. These secretory fluids are injected through the stylet into perforated cells where they modify plant cytoplasm prior to food removal. Some species do not produce specialized feeding sites (viz. Ditylenchus, Subanguina), but may develop a specialized modification of the root system (e.g., unspecialized root galls or a profusion of roots). This review introduces new data on cell types and plant organs stimulated by PPNs using sources varying from traditional histopathology to new holistic methodologies.

One-Step piggyBac Transposon-Based CRISPR/Cas9 Activation of Multiple Genes.

Neural cell fate is determined by a tightly controlled transcription regulatory network during development. The ability to manipulate the expression of multiple transcription factors simultaneously is required to delineate the complex picture of neural cell development. Because of the limited carrying capacity of the commonly used viral vectors, such as lentiviral or retroviral vectors, it is often challenging to perform perturbation experiments on multiple transcription factors. Here we have developed a piggyBac (PB) transposon-based CRISPR activation (CRISPRa) all-in-one system, which allows for simultaneous and stable endogenous transactivation of multiple transcription factors and long non-coding RNAs. As a proof of principle, we showed that the PB-CRISPRa system could accelerate the differentiation of human induced pluripotent stem cells into neurons and astrocytes by triggering endogenous expression of different sets of transcription factors. The PB-CRISPRa system has the potential to become a convenient and robust tool in neuroscience, which can meet the needs of a variety of in vitro and in vivo gain-of-function applications.

Key players in the immune response to biomaterial scaffolds for regenerative medicine.

The compatibility of biomaterials is critical to their structural and biological function in medical applications. The immune system is the first responder to tissue trauma and to a biomaterial implant. The innate immune effector cells, most notably macrophages, play a significant role in the defense against foreign bodies and the formation of a fibrous capsule around synthetic implants. Alternatively, macrophages participate in the pro-regenerative capacity of tissue-derived biological scaffolds. Research is now elucidating the role of the adaptive immune system, and T cells in particular, in directing macrophage response to synthetic and biological materials. Here, we review basic immune cell types and discuss recent research on the role of the immune system in tissue repair and its potential relevance to scaffold design. We will also discuss new emerging immune cell types relevant to biomaterial responses and tissue repair. Finally, prospects for specifically targeting and modulating the immune response to biomaterial scaffolds for enhancing tissue repair and regeneration will be presented.