scholarly journals Signaling roles of phosphoinositides in the retina

2020 ◽  
pp. jlr.TR120000806 ◽  
Author(s):  
Raju V. S. Rajala

The field of phosphoinositide signaling has expanded significantly in recent years. Phosphoinositides (PIs) are universal signaling molecules that directly interact with membrane proteins or with cytosolic proteins containing domains that directly bind phosphoinositides and are recruited to cell membranes. Through the activities of PI kinases and PI phosphatases, seven distinct phosphoinositide lipid molecules are formed from the parent molecule phosphatidylinositol. PI signals regulate a wide range of cellular functions, including cytoskeletal assembly, membrane binding and fusion, ciliogenesis, vesicular transport, and signal transduction. Given the many excellent reviews on phosphoinositide kinases, phosphoinositide phosphatases, and PIs in general, in this review, we discuss recent studies and advances in PI lipid signaling in the retina. We specifically focus on PI lipids from vertebrate (e.g. bovine, rat, mice, toad, and zebrafish) and invertebrate (e.g. drosophila, horseshoe crab, and squid) retinas. We also discuss the importance of PIs revealed from animal models and human diseases, and methods to study PI levels both in vitro and in vivo. We propose that future studies should investigate the function and mechanism of activation of PI-modifying enzymes/phosphatases and further unravel PI regulation and function in the different cell types of the retina.

2020 ◽  
Author(s):  
Chuanjiang He ◽  
Mengxue Liu ◽  
Deming Jiang ◽  
Chunlian Qin ◽  
Tao Liang ◽  
...  

AbstractBioprinting is a common method to replicate geometrical architecture of native tissues. However, it usually fails to modulate cellular arrangements, which is critical for the tissue’s functionality. To our knowledge, no method has successfully addressed this challenge. Here, we report a method of controlling cellular orientation during the bioprinting process by integrating a stretch process into a modified bioprinting frame. We demonstrate that the cellular orientation is a result of cells’ sensing and responding to the tensile stress, instead of shear stress or topographical patterns. Moreover, our method shows a potent capability to induce myoblast differentiation, fusion and maturation without the presence of differentiation medium. As a potential clinical application, we demonstrate that aligned myofibers directly printed onto injured muscle in vivo, can not only repair the structure of damaged tissue, but also recover the muscle functionalities effectively. This study shows that the new method can produce tissues with precise control of cellular arrangements and more clinically viable functionalities.Significance StatementDue to no method could reproduce the exact cellular arrangements of native tissues in engineered tissues, tissue engineering facing difficult in fabricating 3D tissues that possess desirable biological and mechanical functionalities for biomedical applications. For the first time, we report a method of controlling cellular orientation during 3D bio-printing process. This method can be used to produce engineered tissues with controlled cellular arrangement with several different cell types. Moreover, this method shows a potent capability of fabricating fully mature and aligned myofibers in vitro in the absence of differentiation medium. As potential clinical applications, with this method, engineered tissues could be directly printed in vivo with high efficacy of tissue repair and function recovery.


Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 884
Author(s):  
Marta Cherubini ◽  
Scott Erickson ◽  
Kristina Haase

Acting as the primary link between mother and fetus, the placenta is involved in regulating nutrient, oxygen, and waste exchange; thus, healthy placental development is crucial for a successful pregnancy. In line with the increasing demands of the fetus, the placenta evolves throughout pregnancy, making it a particularly difficult organ to study. Research into placental development and dysfunction poses a unique scientific challenge due to ethical constraints and the differences in morphology and function that exist between species. Recently, there have been increased efforts towards generating in vitro models of the human placenta. Advancements in the differentiation of human induced pluripotent stem cells (hiPSCs), microfluidics, and bioprinting have each contributed to the development of new models, which can be designed to closely match physiological in vivo conditions. By including relevant placental cell types and control over the microenvironment, these new in vitro models promise to reveal clues to the pathogenesis of placental dysfunction and facilitate drug testing across the maternal–fetal interface. In this minireview, we aim to highlight current in vitro placental models and their applications in the study of disease and discuss future avenues for these in vitro models.


Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3389
Author(s):  
Ishtiaq Ahmed ◽  
Saif Ur Rehman ◽  
Shiva Shahmohamadnejad ◽  
Muhammad Anjum Zia ◽  
Muhammad Ahmad ◽  
...  

In humans, various sites like cannabinoid receptors (CBR) having a binding affinity with cannabinoids are distributed on the surface of different cell types, where endocannabinoids (ECs) and derivatives of fatty acid can bind. The binding of these substance(s) triggers the activation of specific receptors required for various physiological functions, including pain sensation, memory, and appetite. The ECs and CBR perform multiple functions via the cannabinoid receptor 1 (CB1); cannabinoid receptor 2 (CB2), having a key effect in restraining neurotransmitters and the arrangement of cytokines. The role of cannabinoids in the immune system is illustrated because of their immunosuppressive characteristics. These characteristics include inhibition of leucocyte proliferation, T cells apoptosis, and induction of macrophages along with reduced pro-inflammatory cytokines secretion. The review seeks to discuss the functional relationship between the endocannabinoid system (ECS) and anti-tumor characteristics of cannabinoids in various cancers. The therapeutic potential of cannabinoids for cancer—both in vivo and in vitro clinical trials—has also been highlighted and reported to be effective in mice models in arthritis for the inflammation reduction, neuropathic pain, positive effect in multiple sclerosis and type-1 diabetes mellitus, and found beneficial for treating in various cancers. In human models, such studies are limited; thereby, further research is indispensable in this field to get a conclusive outcome. Therefore, in autoimmune disorders, therapeutic cannabinoids can serve as promising immunosuppressive and anti-fibrotic agents.


RMD Open ◽  
2018 ◽  
Vol 4 (2) ◽  
pp. e000744 ◽  
Author(s):  
Kerstin Klein

The reading of acetylation marks on histones by bromodomain (BRD) proteins is a key event in transcriptional activation. Small molecule inhibitors targeting bromodomain and extra-terminal (BET) proteins compete for binding to acetylated histones. They have strong anti-inflammatory properties and exhibit encouraging effects in different cell types in vitro and in animal models resembling rheumatic diseases in vivo. Furthermore, recent studies that focus on BRD proteins beyond BET family members are discussed.


2017 ◽  
Vol 216 (10) ◽  
pp. 3405-3422 ◽  
Author(s):  
Vasja Urbančič ◽  
Richard Butler ◽  
Benjamin Richier ◽  
Manuel Peter ◽  
Julia Mason ◽  
...  

Filopodia have important sensory and mechanical roles in motile cells. The recruitment of actin regulators, such as ENA/VASP proteins, to sites of protrusion underlies diverse molecular mechanisms of filopodia formation and extension. We developed Filopodyan (filopodia dynamics analysis) in Fiji and R to measure fluorescence in filopodia and at their tips and bases concurrently with their morphological and dynamic properties. Filopodyan supports high-throughput phenotype characterization as well as detailed interactive editing of filopodia reconstructions through an intuitive graphical user interface. Our highly customizable pipeline is widely applicable, capable of detecting filopodia in four different cell types in vitro and in vivo. We use Filopodyan to quantify the recruitment of ENA and VASP preceding filopodia formation in neuronal growth cones, and uncover a molecular heterogeneity whereby different filopodia display markedly different responses to changes in the accumulation of ENA and VASP fluorescence in their tips over time.


2022 ◽  
Author(s):  
Homa Majd ◽  
Ryan M Samuel ◽  
Jonathan T Ramirez ◽  
Ali Kalantari ◽  
Kevin Barber ◽  
...  

The enteric nervous system (ENS) plays a central role in gut physiology and mediating the crosstalk between the gastrointestinal (GI) tract and other organs. The human ENS has remained elusive, highlighting the need for an in vitro modeling and mapping blueprint. Here we map out the developmental and functional features of the human ENS, by establishing robust and scalable 2D ENS cultures and 3D enteric ganglioids from human pluripotent stem cells (hPSCs). These models recapitulate the remarkable neuronal and glial diversity found in primary tissue and enable comprehensive molecular analyses that uncover functional and developmental relationships within these lineages. As a salient example of the power of this system, we performed in-depth characterization of enteric nitrergic neurons (NO neurons) which are implicated in a wide range of GI motility disorders. We conducted an unbiased screen and identified drug candidates that modulate the activity of NO neurons and demonstrated their potential in promoting motility in mouse colonic tissue ex vivo. We established a high-throughput strategy to define the developmental programs involved in NO neuron specification and discovered that PDGFR inhibition boosts the induction of NO neurons in enteric ganglioids. Transplantation of these ganglioids in the colon of NO neuron-deficient mice results in extensive tissue engraftment, providing a xenograft model for the study of human ENS in vivo and the development of cell-based therapies for neurodegenerative GI disorders. These studies provide a framework for deciphering fundamental features of the human ENS and designing effective strategies to treat enteric neuropathies.  


2018 ◽  
Vol 53 ◽  
pp. 22-36 ◽  
Author(s):  
Habibollah Faraji ◽  
Reza Nedaeinia ◽  
Esmaeil Nourmohammadi ◽  
Bizan Malaekeh-Nikouei ◽  
Hamid Reza Sadeghnia ◽  
...  

Nanotechnology as a multidisciplinary and scientific innovation plays an important role in numerous biomedical applications, such as molecular imaging, biomarkers and biosensors and also drug delivery. A wide range of studies have been conducted on using of nanoparticles for early diagnosis and targeted drug therapy of various diseases. In fact, the small size, customized surface, upgraded solubility, or multi-functionality of nanoparticles enabled them to interact with complex cellular functions in new ways which opened many doors and created new biomedical applications. These studies demonstrated that nanotechnology vehicles can formulate biological products effectively, and this nano-formulated products with a potent ability against different diseases, were represented to have better biocompatibility, bioaccessibility and efficacy, under in vitro and in vivo conditions.


Blood ◽  
1998 ◽  
Vol 92 (9) ◽  
pp. 3226-3239 ◽  
Author(s):  
Ping Zhou ◽  
Liping Qian ◽  
Christine K. Bieszczad ◽  
Randolph Noelle ◽  
Michael Binder ◽  
...  

Abstract Mcl-1 is a member of the Bcl-2 family that is expressed in early monocyte differentiation and that can promote viability on transfection into immature myeloid cells. However, the effects of Mcl-1 are generally short lived compared with those of Bcl-2 and are not obvious in some transfectants. To further explore the effects of this gene, mice were produced that expressed Mcl-1 as a transgene in hematolymphoid tissues. The Mcl-1 transgene was found to cause moderate viability enhancement in a wide range of hematopoietic cell types, including lymphoid (B and T) as well as myeloid cells at both immature and mature stages of differentiation. However, enhanced hematopoietic capacity in transgenic bone marrow and spleen was not reflected in any change in pool sizes in the peripheral blood. In addition, among transgenic cells, mature T cells remained long lived compared with B cells and macrophages could live longer than either of these. Interestingly, when hematopoietic cells were maintained in tissue culture in the presence of interleukin-3, Mcl-1 enhanced the probability of outgrowth of continuously proliferating myeloid cell lines. Thus, Mcl-1 transgenic cells remained subject to normal in vivo homeostatic mechanisms controlling viable cell number, but these constraints could be overridden under specific conditions in vitro. Within the organism, Bcl-2 family members may act at “viability gates” along the differentiation continuum, functioning as part of a system for controlled hematopoietic cell amplification. Enforced expression of even a moderate viability-promoting member of this family such as Mcl-1, within a conducive intra- and extracellular environment in isolation from normal homeostatic constraints, can substantially increase the probability of cell immortalization. © 1998 by The American Society of Hematology.


Blood ◽  
1974 ◽  
Vol 44 (5) ◽  
pp. 707-713 ◽  
Author(s):  
Michael B. Harris ◽  
Isaac Djerassi ◽  
Elias Schwartz ◽  
Richard K. Root

Abstract Preparation of granulocytes for transfusion in high yield and relatively free of contamination by other cell types has been made possible by the technique of continuous-flow filtration leukapheresis (CFFL). Since previous work suggested that granulocytes collected in this manner may have impaired viability and function, a detailed study of the bactericidal, metabolic, and chemotactic properties of such cells was performed and compared to control cells obtained from the same donors prior to CFFL. The granulocyte percentage of the cell suspensions obtained by CFFL averaged 94.5% ± 1.5% compared to 82.5% ± 1.8% for the controls (p < 0.001) with viability of the PMNs determined by trypan blue exclusion being 97.5% ± 0.9% and 98.2% ± 0.5%, respectively. The phogocytic, metabolic (14C-I-glucose oxidation and protein iodination) and chemotactic properties of both cell types were equivalent in suspensions equalized for granulocyte content. These findings indicate that CFFL technique employed does not impair granulocyte viability or function in vitro. Studies of the in vivo survival and function of CFFL granulocytes are necessary to evaluate their efficacy in combating infection in severely leukopenic patients.


2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Julie Williams ◽  
Sanlin Robinson ◽  
Babak Alaei ◽  
Kimberly Homan ◽  
Maryam Clausen ◽  
...  

Abstract Background and Aims Questions abound regarding the translation of in vitro 2D cell culture systems to the human setting. This is especially true of the kidney in which there is a complex hierarchical structure and a multitude of cell types. While it is well accepted that extracellular matrix plays a large part in directing cellular physiology emerging research has highlighted the importance of shear stresses and flow rates too. To fully recapitulate the normal gene expression and function of a particular renal cell type how important is it to completely reconstitute their in vivo surroundings? Method To answer this question, we have cultured proximal tubular (PT) epithelial cells in a 3-dimensional channel embedded within an engineered extracellular matrix (ECM) under physiological flow that is colocalised with an adjacent channel lined with renal microvascular endothelial cells that mimic a peritubular capillary. Modifications to the system were made to allow up to 12 chips to be run in parallel in an easily handleable form. After a period of maturation under continuous flow, both cell types were harvested for RNAseq analyses. RNA expression data was compared with cells cultured under static 2-dimensional conditions on plastic or the engineered ECM. Additionally, the perfusion of glucose through this 3D vascularised PT model has been investigated in the presence and absence of known diabetes modulating agents. Results PCA of RNAseq data showed that a) static non-coated, b) static matrix-coated and c) flow matrix-coated conditions separated into 3 distinct groups, while cell co-culture had less impact. Analysis of transcriptomic signatures showed that many genes were modulated by the matrix with additional genes influenced under flow conditions. Several of these genes, classified as transporters, are of particular importance when using this model to assess drug uptake and safety implications. Co-culture regulated some interesting genes, but fewer than anticipated. Preliminary experiments are underway to monitor glucose uptake and transport between tubules under different conditions. Conclusion We have developed a medium throughput system in which matrix and flow modulate gene expression. This system can be used to study the physiology of molecular cross-talk between cells. Ongoing analysis will further consider relevance to human physiology.


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