scholarly journals Advances in modelling the human microbiome–gut–brain axis in vitro

2021 ◽  
Author(s):  
Chrysanthi-Maria Moysidou ◽  
Róisín M. Owens
Keyword(s):  
Animal Models ◽  
Cell Biology ◽  
Materials Science ◽  
Human Microbiome ◽  
Paradigm Shifts ◽  
Bidirectional Communication ◽  
Wide Range ◽  
And Function

The human gut microbiome has emerged as a key player in the bidirectional communication of the gut–brain axis, affecting various aspects of homeostasis and pathophysiology. Until recently, the majority of studies that seek to explore the mechanisms underlying the microbiome–gut–brain axis cross-talk, relied almost exclusively on animal models, and particularly gnotobiotic mice. Despite the great progress made with these models, various limitations, including ethical considerations and interspecies differences that limit the translatability of data to human systems, pushed researchers to seek for alternatives. Over the past decades, the field of in vitro modelling of tissues has experienced tremendous growth, thanks to advances in 3D cell biology, materials, science and bioengineering, pushing further the borders of our ability to more faithfully emulate the in vivo situation. The discovery of stem cells has offered a new source of cells, while their use in generating gastrointestinal and brain organoids, among other tissues, has enabled the development of novel 3D tissues that better mimic the native tissue structure and function, compared with traditional assays. In parallel, organs-on-chips technology and bioengineered tissues have emerged as highly promising alternatives to animal models for a wide range of applications. Here, we discuss how recent advances and trends in this area can be applied in host–microbe and host–pathogen interaction studies. In addition, we highlight paradigm shifts in engineering more robust human microbiome-gut-brain axis models and their potential to expand our understanding of this complex system and hence explore novel, microbiome-based therapeutic approaches.

scholarly journals hPSC-Derived Enteric Ganglioids Model Human ENS Development and Function

2022 ◽  
Author(s):  
Homa Majd ◽  
Ryan M Samuel ◽  
Jonathan T Ramirez ◽  
Ali Kalantari ◽  
Kevin Barber ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Xenograft Model ◽  
Developmental Relationships ◽  
Drug Candidates ◽  
Effective Strategies ◽  
Wide Range ◽  
Functional Features ◽  
And Function

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.  

scholarly journals Role of Exosomes in Islet Transplantation

2021 ◽  
Vol 12 ◽  
Author(s):  
Jordan Mattke ◽  
Srividya Vasu ◽  
Carly M. Darden ◽  
Kenjiro Kumano ◽  
Michael C. Lawrence ◽  
...  
Keyword(s):  
Islet Transplantation ◽  
Graft Function ◽  
Pancreatic Islet Transplantation ◽  
Complex Molecules ◽  
Wide Range ◽  
And Function ◽  
Antigen Presenting

Exosomes are known for their ability to transport nucleic acid, lipid, and protein molecules, which allows for communication between cells and tissues. The cargo of the exosomes can have a variety of effects on a wide range of targets to mediate biological function. Pancreatic islet transplantation is a minimally invasive cell replacement therapy to prevent or reverse diabetes mellitus and is currently performed in patients with uncontrolled type 1 diabetes or chronic pancreatitis. Exosomes have become a focus in the field of islet transplantation for the study of diagnostic markers of islet cell viability and function. A growing list of miRNAs identified from exosomes collected during the process of isolating islets can be used as diagnostic biomarkers of islet stress and damage, leading to a better understanding of critical steps of the isolation procedure that can be improved to increase islet yield and quality. Exosomes have also been implicated as a possible contributor to islet graft rejection following transplantation, as they carry donor major histocompatibility complex molecules, which are then processed by recipient antigen-presenting cells and sensed by the recipient immune cells. Exosomes may find their way into the therapeutic realm of islet transplantation, as exosomes isolated from mesenchymal stem cells have shown promising results in early studies that have seen increased viability and functionality of isolated and grafted islets in vitro as well as in vivo. With the study of exosomes still in its infancy, continued research on the role of exosomes in islet transplantation will be paramount to understanding beta cell regeneration and improving long-term graft function.

scholarly journals Developments and Opportunities for 3D Bioprinted Organoids

2021 ◽  
Vol 7 (3) ◽  
pp. 364
Author(s):  
Ya Ren ◽  
Xue Yang ◽  
Zhengjiang Ma ◽  
Xin Sun ◽  
Yuxin Zhang ◽  
...  
Keyword(s):  
Stem Cells ◽  
Cell Biology ◽  
Adult Stem Cells ◽  
Materials Science ◽  
Disease Modeling ◽  
Three Dimensional ◽  
Key Characteristics ◽  
And Function ◽  
Further Development

Organoids developed from pluripotent stem cells or adult stem cells are three-dimensional cell cultures possessing certain key characteristics of their organ counterparts, and they can mimic certain biological developmental processes of organs in vitro. Therefore, they have promising applications in drug screening, disease modeling, and regenerative repair of tissues and organs. However, the construction of organoids currently faces numerous challenges, such as breakthroughs in scale size, vascularization, better reproducibility, and precise architecture in time and space. Recently, the application of bioprinting has accelerated the process of organoid construction. In this review, we present current bioprinting techniques and the application of bioinks and summarize examples of successful organoid bioprinting. In the future, a multidisciplinary combination of developmental biology, disease pathology, cell biology, and materials science will aid in overcoming the obstacles pertaining to the bioprinting of organoids. The combination of bioprinting and organoids with a focus on structure and function can facilitate further development of real organs.

scholarly journals Self-similar synchronization of calcium and membrane potential transitions during AP cycles predict HR across species

2020 ◽  
Author(s):  
Syevda Tagirova Sirenko ◽  
Kenta Tsutsui ◽  
Kirill Tarasov ◽  
Dongmei Yang ◽  
Ashley N Wirth ◽  
...  
Keyword(s):  
Heart Rate ◽  
Animal Models ◽  
Animal Studies ◽  
Power Laws ◽  
Single Species ◽  
Cellular Mechanisms ◽  
Wide Range ◽  
Self Similar

AbstractBackgroundTranslation of knowledge of sinoatrial nodal “SAN” automaticity gleaned from animal studies to human dysrhythmias, e.g. “Sick Sinus” Syndrome (SSS) requiring electronic pacemaker insertion has been sub-optimal, largely because heart rate (HR) varies widely across species.ObjectivesTo discover regulatory universal mechanisms of normal automaticity in SAN pacemaker cells that are self-similar across species.MethodSub-cellular Ca2+ releases, whole cell AP-induced Ca2+ transients and APs were recorded in isolated mouse, guinea-pig, rabbit and human SAN cells. Parametric Ca2+ and Vm Kinetic Transitions (PCVKT) during phases of AP cycles from their ignition to recovery were quantified.ResultsAlthough both action potential cycle lengths (APCL) and PCVKT during AP cycles differed across species by ten-fold, trans-species scaling of PCVKT during AP cycles and scaling, of PCVKT to APCL in cells in vitro, EKG RR intervals in vivo, and BM were self-similar (obeyed power laws) across species. Thus, APCL in vitro, HR in vivo, and BM of any species can be predicted by PCVKT during AP cycles in SAN cells measured in any single species in vitro.ConclusionsIn designing optimal HR to match widely different BM and energy requirements from mice to humans, nature did not “reinvent pacemaker cell wheels”, but differentially scaled kinetics of gears that regulate the rates at which the “wheels spin”. This discovery will facilitate the development of novel pharmalogic therapies and biologic pacemakers featuring a normal, wide-range rate regulation in animal models and the translation of these to humans to target recalcitrant human SSS.Condensed AbstractStudies in animal models are an important facet of cardiac arrhythmia research. Because HR differs by over ten-fold between some animals and humans, translation of knowledge about regulatory mechanisms of SAN normal automaticity gleaned from studies in animal models to target human SSS has been sub-optimal. Our findings demonstrating that trans-species self-similarity of sub-cellular and cellular mechanisms that couple Ca2+ to Vm during AP cycles can predict heart rate in vivo from mice to humans will inform on the design of novel studies in animal models and facilitate translation of this knowledge to target human disease.

scholarly journals Structure-guided disruption of pseudopilus tip inhibits Type II secretion in Pseudomonas aeruginosa

2018 ◽  
Author(s):  
Zongchao Jia ◽  
Yichen Zhang ◽  
Frederick Faucher ◽  
Wenwen Zhang ◽  
Shu Wang ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Function Analysis ◽  
Type Ii Secretion ◽  
Type Ii ◽  
Core Complex ◽  
Wide Range ◽  
Interaction Interface ◽  
And Function

Pseudomonas aeruginosa utilizes the Type II secretion system (T2SS) to translocate a wide range of large, structured protein virulence factors through the periplasm to the extracellular environment for infection. In the T2SS, five pseudopilins assemble into the pseudopilus that acts as a piston to extrude exoproteins out of cells. Through structure determination of the pseudopilin complexes of XcpVWX and XcpVW and function analysis, we have confirmed that two minor pseudopilins, XcpV and XcpW, constitute a core complex indispensable to the pseudopilus tip. The absence of either XcpV or -W resulted in the non-functional T2SS. Our small-angle X-ray scattering experiment for the first time revealed the architecture of the entire pseudopilus tip and established the working model. Based on the interaction interface of complexes, we have developed inhibitory peptides. The structure-based peptides not only disrupted of the XcpVW core complex and the entire pseudopilus tip in vitro but also inhibited the T2SS in vivo. More importantly, these peptides effectively reduced the virulence of P. aeruginosa towards Caenorhabditis elegans.

scholarly journals Signaling roles of phosphoinositides in the retina

2020 ◽  
pp. jlr.TR120000806 ◽  
Author(s):  
Raju V. S. Rajala
Keyword(s):  
Cell Types ◽  
Cellular Functions ◽  
Parent Molecule ◽  
Phosphoinositide Signaling ◽  
Wide Range ◽  
The Many ◽  
And Function ◽  
Different Cell Types

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.

scholarly journals BrainPhys neuronal medium optimized for imaging and optogenetics in vitro

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Michael Zabolocki ◽  
Kasandra McCormack ◽  
Mark van den Hurk ◽  
Bridget Milky ◽  
Andrew P. Shoubridge ◽  
...  
Keyword(s):  
Cell Biology ◽  
Culture Conditions ◽  
Cellular Reprogramming ◽  
Synaptic Activity ◽  
Neuronal Cultures ◽  
Neuronal Viability ◽  
Human Neurons ◽  
Wide Range ◽  
And Function

AbstractThe capabilities of imaging technologies, fluorescent sensors, and optogenetics tools for cell biology are advancing. In parallel, cellular reprogramming and organoid engineering are expanding the use of human neuronal models in vitro. This creates an increasing need for tissue culture conditions better adapted to live-cell imaging. Here, we identify multiple caveats of traditional media when used for live imaging and functional assays on neuronal cultures (i.e., suboptimal fluorescence signals, phototoxicity, and unphysiological neuronal activity). To overcome these issues, we develop a neuromedium called BrainPhys™ Imaging (BPI) in which we optimize the concentrations of fluorescent and phototoxic compounds. BPI is based on the formulation of the original BrainPhys medium. We benchmark available neuronal media and show that BPI enhances fluorescence signals, reduces phototoxicity and optimally supports the electrical and synaptic activity of neurons in culture. We also show the superior capacity of BPI for optogenetics and calcium imaging of human neurons. Altogether, our study shows that BPI improves the quality of a wide range of fluorescence imaging applications with live neurons in vitro while supporting optimal neuronal viability and function.

scholarly journals Nano- and microstructured materials for in vitro studies of the physiology of vascular cells

2016 ◽  
Vol 7 ◽  
pp. 1620-1641 ◽  
Author(s):  
Alexandra M Greiner ◽  
Adria Sales ◽  
Hao Chen ◽  
Sarah A Biela ◽  
Dieter Kaufmann ◽  
...  
Keyword(s):  
Cell Biology ◽  
Materials Science ◽  
Cell Interaction ◽  
Culture Conditions ◽  
Vascular Cells ◽  
Vascular Cell ◽  
Nanostructured Surfaces ◽  
Cell Responses

The extracellular environment of vascular cells in vivo is complex in its chemical composition, physical properties, and architecture. Consequently, it has been a great challenge to study vascular cell responses in vitro, either to understand their interaction with their native environment or to investigate their interaction with artificial structures such as implant surfaces. New procedures and techniques from materials science to fabricate bio-scaffolds and surfaces have enabled novel studies of vascular cell responses under well-defined, controllable culture conditions. These advancements are paving the way for a deeper understanding of vascular cell biology and materials–cell interaction. Here, we review previous work focusing on the interaction of vascular smooth muscle cells (SMCs) and endothelial cells (ECs) with materials having micro- and nanostructured surfaces. We summarize fabrication techniques for surface topographies, materials, geometries, biochemical functionalization, and mechanical properties of such materials. Furthermore, various studies on vascular cell behavior and their biological responses to micro- and nanostructured surfaces are reviewed. Emphasis is given to studies of cell morphology and motility, cell proliferation, the cytoskeleton and cell-matrix adhesions, and signal transduction pathways of vascular cells. We finalize with a short outlook on potential interesting future studies.

scholarly journals Properties of Resveratrol:In VitroandIn VivoStudies about Metabolism, Bioavailability, and Biological Effects in Animal Models and Humans

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
J. Gambini ◽  
M. Inglés ◽  
G. Olaso ◽  
R. Lopez-Grueso ◽  
V. Bonet-Costa ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Animal Models ◽  
Red Wine ◽  
Anticancer Agent ◽  
Biological Effects ◽  
Biological Properties ◽  
Wide Range ◽  
Therapeutic Properties

Plants containing resveratrol have been used effectively in traditional medicine for over 2000 years. It can be found in some plants, fruits, and derivatives, such as red wine. Therefore, it can be administered by either consuming these natural products or intaking nutraceutical pills. Resveratrol exhibits a wide range of beneficial properties, and this may be due to its molecular structure, which endow resveratrol with the ability to bind to many biomolecules. Among these properties its activity as an anticancer agent, a platelet antiaggregation agent, and an antioxidant, as well as its antiaging, antifrailty, anti-inflammatory, antiallergenic, and so forth activities, is worth highlighting. These beneficial biological properties have been extensively studied in humans and animal models, bothin vitroandin vivo. The issue of bioavailability of resveratrol is of paramount importance and is determined by its rapid elimination and the fact that its absorption is highly effective, but the first hepatic step leaves little free resveratrol. Clarifying aspects like stability and pharmacokinetics of resveratrol metabolites would be fundamental to understand and apply the therapeutic properties of resveratrol.

Identification and Function of Hematopoietic Stem and Progenitor Cell Specific Micrornas.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2631-2631
Author(s):  
Bernhard Gentner ◽  
Alice Giustacchini ◽  
Francesco Boccalatte ◽  
Giulia Schira ◽  
Massimo Saini ◽  
...  
Keyword(s):  
Cell Biology ◽  
Conflicts Of Interest ◽  
Human Cord Blood ◽  
Hematopoietic Stem ◽  
Long Run ◽  
Stem And Progenitor Cells ◽  
Phosphoinositide 3 Kinase ◽  
And Function

Abstract Abstract 2631 Little is known about microRNA function in hematopoietic stem and progenitor cells (HSPC). Using a lentivector genetic reporter strategy to functionally detect miRNA activity in hematopoietic cells at single cell resolution, we identified several miRNAs which were specifically expressed in mouse and human HSC and early progenitors, defined according to cell surface phenotype and functional repopulation assays. One of these HSPC-specific miRNAs, miR-126, was further studied. We generated a stable miR-126 knockdown (kd) or forced its expression (“knock-in”, ki) in mouse HSPC using lentiviral vectors. Kd or ki cells were competitively transplanted with congenic, control vector-transduced cells, and hematopoietic chimerism was followed for >1 year in both primary and secondary recipients. miR-126 kd HSPC displayed enhanced myeloid and/or lymphoid contribution during the early phases of reconstitution, while they subsequently contributed similarly as the control cells. When this steady state bone marrow (BM) was transplanted into secondary recipients, we noted an even more pronounced over-contribution of miR-126 kd cells to hematopoiesis. In the long run, however, some secondary mice showed signs of exhaustion of miR-126 kd cells. These data suggest that miR-126 kd enhances hematopoiesis, likely at the stem/early progenitor level and in particular under stress conditions. On the other hand, forced expression of miR-126 (ki) resulted in an early competitive disadvantage in vivo, with progressively decreasing contribution to all hematopoietic lineages, paralleled by a nearly complete depletion of Kit+Sca+Lin- (KSL) miR-126 ki cells in the BM at 6 weeks after transplant. At 3 weeks post-transplant, when miR-126 ki KSL cells could still be detected, we found an increased proliferative index in these cells as judged by EdU incorporation in vivo, paralleled by a higher hematopoietic output respect to control cells at week 2–4 after transplant. These data suggest that miR-126 ki might favor HSC commitment at the cost of self-renewal. This phenotype was specific for miR-126 and not due to vector toxicity, as we demonstrate stable, long term overexpression of several control miRNAs in vivo. Moreover, miR-126 ki cells showed normal clonogenic activity in vitro. We then optimized a protocol to stably knock down miR-126 in human cord blood (huCB) HSPC, and validated this approach by demonstrating upregulation of previously described miR-126 targets including the beta subunit of phosphoinositide-3-kinase. Manipulation of miR-126 activity changed cell growth and differentiation of huCB, and we show altered activation of key signal transduction pathways upon miR-126 kd. Identification of additional miR-126 targets is ongoing using unbiased proteomic and transcriptomic approaches. In summary, these data suggest that a narrow range of miR-126 activity is required for robust and sustained HSC function, and that its manipulation may provide novel insights into stem cell biology. Disclosures: No relevant conflicts of interest to declare.

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