scholarly journals Brick Strex: a robust device built of LEGO bricks for mechanical manipulation of cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Elina Mäntylä ◽  
Teemu O. Ihalainen
Keyword(s):  
Molecular Mechanisms ◽  
Compressive Force ◽  
Tissue Mechanics ◽  
Cell Junctions ◽  
Physical Factors ◽  
Force Transmission ◽  
Cell Nuclei ◽  
Microscopy Imaging ◽  
Robust Solution ◽  
Mechanical Manipulation

AbstractCellular forces, mechanics and other physical factors are important co-regulators of normal cell and tissue physiology. These cues are often misregulated in diseases such as cancer, where altered tissue mechanics contribute to the disease progression. Furthermore, intercellular tensile and compressive force-related signaling is highlighted in collective cell behavior during development. However, the mechanistic understanding on the role of physical forces in regulation of cellular physiology, including gene expression and signaling, is still lacking. This is partly because studies on the molecular mechanisms of force transmission require easily controllable experimental designs. These approaches should enable both easy mechanical manipulation of cells and, importantly, readouts ranging from microscopy imaging to biochemical assays. To achieve a robust solution for mechanical manipulation of cells, we developed devices built of LEGO bricks allowing manual, motorized and/or cyclic cell stretching and compression studies. By using these devices, we show that $$\upbeta$$ β -catenin responds differentially to epithelial monolayer stretching and lateral compression, either localizing more to the cell nuclei or cell–cell junctions, respectively. In addition, we show that epithelial compression drives cytoplasmic retention and phosphorylation of transcription coregulator YAP1. We provide a complete part listing and video assembly instructions, allowing other researchers to build and use the devices in cellular mechanics-related studies.

scholarly journals Brick Strex – A Robust Device Built of LEGO® Bricks for Mechanical Manipulation of Cells

2021 ◽  
Author(s):  
Elina Mäntylä ◽  
Teemu Olavi Ihalainen
Keyword(s):  
Molecular Mechanisms ◽  
Compressive Force ◽  
Tissue Mechanics ◽  
Cell Junctions ◽  
Physical Factors ◽  
Force Transmission ◽  
Cell Nuclei ◽  
Microscopy Imaging ◽  
Robust Solution ◽  
Mechanical Manipulation

Abstract Cellular forces, mechanics and other physical factors are important co-regulators of normal cell and tissue physiology. These cues are often misregulated in diseases such as cancer, where altered tissue mechanics contribute to the disease progression. Furthermore, intercellular tensile and compressive force related signaling is highlighted in collective cell behavior during development. However, the mechanistic understanding on the role of physical forces in regulation of cellular physiology, including gene expression and signaling, is still lacking. This is partly because studies on the molecular mechanisms of force transmission require easily controllable experimental designs. These approaches should enable both easy mechanical manipulation of cells and, importantly, readouts ranging from microscopy imaging to biochemical assays. To achieve a robust solution for mechanical manipulation of cells, we developed devices built of LEGO® bricks allowing cell stretching and compression studies. By using these devices, we show that b-catenin responds differentially to epithelial monolayer stretching and compression, either localizing more to the cell nuclei or cell-cell junctions, respectively. In addition, we show that epithelial compression drives cytoplasmic retention and phosphorylation of transcription coregulator YAP1. We provide a complete part listing and video assembly instructions, allowing other researchers to build and use the devices in cellular mechanics -related studies.

Relationship Between Gamma-glutamyl Transpeptidase Activity and Inflammatory Response in Lichen Planus

2018 ◽  
Vol 69 (3) ◽  
pp. 739-743 ◽  
Author(s):  
Madalina Irina Mitran ◽  
Ilinca Nicolae ◽  
Corina Daniela Ene ◽  
Cristina Iulia Mitran ◽  
Clara Matei ◽  
...  
Keyword(s):  
Inflammatory Response ◽  
Lichen Planus ◽  
Inflammatory Process ◽  
Molecular Mechanisms ◽  
Functional Adaptation ◽  
Physical Factors ◽  
Inflammatory Disorder ◽  
Gamma Glutamyl Transpeptidase ◽  
Gamma Glutamyl ◽  
Glutamyl Transpeptidase

Chemicals used in the manufacture of synthetic fibers have been associated with undesirable side effects such as itching or skin lesions and it seems that they are involved in the induction of pathological processes such as oxidative stress and inflammation. Lichen planus (LP) can be regarded as an inflammatory disorder, chemical and physical factors playing an important role in the perpetuation of the inflammatory process. Gamma-glutamyl transpeptidase (GGT) plays an important role in the preservation of skin architecture and modulation of skin inflammation. In this study, we found that GGT activity is increased in LP patients with mild inflammation, whilst GGT is inactivated under conditions of severe inflammation. Therefore, GGT is involved in the inflammatory process, but there is no a positive correlation between its activity and the intensity of the inflammatory response. This functional adaptation of the enzyme may be due to down-regulation of its synthesis under free radical overload conditions. Understanding the molecular mechanisms involved in the modulation of intracellular redox homeostasis is an important step in the pharmacological management of patients with LP.

Signaling Mechanisms Regulating Vascular Endothelial Barrier Function

2017 ◽  
pp. 17-42
Author(s):  
Mohammad Tauseef ◽  
Madeeha Aqil ◽  
Dolly Mehta
Keyword(s):  
Molecular Mechanisms ◽  
Endothelial Permeability ◽  
Cell Junctions ◽  
Vascular Endothelial ◽  
Gap Formation ◽  
Endothelial Lining ◽  
Inflammatory Conditions ◽  
Signaling Mechanisms ◽  
Life Threatening ◽  
Endothelial Gaps

During inflammatory conditions, such as sepsis, myocardial infarction and acute respiratory distress syndrome, endothelial cell-cell junctions start to disrupt because of the internalization of the junctional proteins such as vascular endothelial (VE) cadherin. This leads to the formation of minute inter-endothelial gaps, and the infiltration of protein-rich fluid and immune cells in the interstitial space. If remains unchecked, the persistent buildup of edema underlying the endothelial lining sets the stage for the serious life-threatening complications and ultimately leads to the multi-organ failure and death. Thus, to determine the molecular mechanisms underlying the opening and resolution phase of the gap formation, will provide an insight to better understand the pathology of the cardiovascular and pulmonary inflammatory disorders. In this chapter, we will discuss about how the signaling mechanisms activated by the known inflammatory molecules increase endothelial permeability.

scholarly journals Molecular regulation of NKCC2 in the thick ascending limb

2011 ◽  
Vol 301 (6) ◽  
pp. F1143-F1159 ◽  
Author(s):  
Gustavo R. Ares ◽  
Paulo S. Caceres ◽  
Pablo A. Ortiz
Keyword(s):  
Blood Pressure ◽  
Protein Interactions ◽  
Membrane Trafficking ◽  
Molecular Mechanisms ◽  
Blood Pressure Regulation ◽  
Renal Physiology ◽  
Physical Factors ◽  
Thick Ascending Limb ◽  
Pressure Regulation ◽  
Physiological Control

The kidney plays an essential role in blood pressure regulation by controlling short-term and long-term NaCl and water balance. The thick ascending limb of the loop of Henle (TAL) reabsorbs 25–30% of the NaCl filtered by the glomeruli in a process mediated by the apical Na+-K+-2Cl− cotransporter NKCC2, which allows Na+ and Cl− entry from the tubule lumen into TAL cells. In humans, mutations in the gene coding for NKCC2 result in decreased or absent activity characterized by severe salt and volume loss and decreased blood pressure (Bartter syndrome type 1). Opposite to Bartter's syndrome, enhanced NaCl absorption by the TAL is associated with human hypertension and animal models of salt-sensitive hypertension. TAL NaCl reabsorption is subject to exquisite control by hormones like vasopressin, parathyroid, glucagon, and adrenergic agonists (epinephrine and norepinephrine) that stimulate NaCl reabsorption. Atrial natriuretic peptides or autacoids like nitric oxide and prostaglandins inhibit NaCl reabsorption, promoting salt excretion. In general, the mechanism by which hormones control NaCl reabsorption is mediated directly or indirectly by altering the activity of NKCC2 in the TAL. Despite the importance of NKCC2 in renal physiology, the molecular mechanisms by which hormones, autacoids, physical factors, and intracellular ions regulate NKCC2 activity are largely unknown. During the last 5 years, it has become apparent that at least three molecular mechanisms determine NKCC2 activity. As such, membrane trafficking, phosphorylation, and protein-protein interactions have recently been described in TALs and heterologous expression systems as mechanisms that modulate NKCC2 activity. The focus of this review is to summarize recent data regarding NKCC2 regulation and discuss their potential implications in physiological control of TAL function, renal physiology, and blood pressure regulation.

scholarly journals Cardiovascular phenotyping of the first mouse model of Sarcoidosis

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
C Bueno Beti ◽  
C Lim ◽  
A Protonotarios ◽  
A Kiss ◽  
M.N Sheppard ◽  
...  
Keyword(s):  
Mouse Model ◽  
Molecular Mechanisms ◽  
Left Ventricular ◽  
Cell Junctions ◽  
Left Ventricular Ejection ◽  
Unknown Etiology ◽  
Funding Source ◽  
Ventricular Ejection Fraction ◽  
Arrhythmogenic Substrate ◽  
Inflammatory Infiltrates

Abstract Introduction Sarcoidosis is a potentially life-threatening, inflammatory, granulomatous disease that affects multiple organs including the heart. Heretofore, its unknown etiology had hindered the creation of experimental models and the understanding of the molecular mechanisms of pathogenesis behind it. Purpose To extensively phenotype the heart of the first mouse model of sarcoidosis created through deletion of the tuberous sclerosis 2 (Tsc2) gene in the CD11c-positive macrophage population. Methods Tsc2 fl/fl CD11c Cre+ (Tsc2-KO; n=7) and Tsc2 fl/fl CD11c Cre- (Tsc2-WT; n=7) mice were subjected to echocardiography at 25 weeks of age (woa) to assess myocardial dimensions and function. Hearts of 13 and 25woa animals were subjected to histological and immunological stains to assess tissue changes, subtype inflammatory infiltrates and examine the localization of key proteins shown to be re-distributed in patients. Results At 13 woa, Tsc2-KO animals show inflammatory infiltrates; subtyped mainly as macrophages as well as evidence of myocyte destruction. At 25 woa, the number of inflammatory cells is significantly higher and there is heavy fibrotic replacement primarily in the septum and trabeculae. Older animals also show giant cells and non-necrotizing granulomas. The hearts show heterogeneous gap junction remodeling known to constitute an arrhythmogenic substrate and lack of immunoreactive signal for the desmosomal protein plakoglobin from the cell-cell junctions just as described in patients. The left ventricular ejection fraction and LV morphology was not significantly different between the two groups (EF: 64±4% in Tsc2-KO vs 64±2% in Tsc2-WT; LV end-systolic diameter: 4.51±0.54 mm in Tsc2-KO vs 4.59±0.29 mm in Tsc2-WT). However, there was a strong trend towards increasing filling pressure (E/e'ratio; 14.24±4.01 vs 12.15±2.54) and mean pulmonary pressure (21±6 vs 18±3 mmHg) in Tsc2-KO mice compared to controls suggesting diastolic dysfunction. Conclusion Hearts of the Tsc2 fl/fl CD11c Cre+ animals show a phenotype highly reminiscent of cardiac sarcoidosis in patients. We anticipate that this model will be very useful in deciphering molecular mechanisms of pathogenesis as well as testing much-needed mechanism-based therapies. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): British Heart Foundation - PG/18/27/33616

scholarly journals Nucleosome–nucleosome interactions via histone tails and linker DNA regulate nuclear rigidity

2017 ◽  
Vol 28 (11) ◽  
pp. 1580-1589 ◽  
Author(s):  
Yuta Shimamoto ◽  
Sachiko Tamura ◽  
Hiroshi Masumoto ◽  
Kazuhiro Maeshima
Keyword(s):  
Molecular Mechanisms ◽  
Mechanical Response ◽  
Nuclear Architecture ◽  
Living Cells ◽  
Genome Integrity ◽  
Biological Processes ◽  
Cell Nuclei ◽  
Histone Tails ◽  
Insight Into

Cells, as well as the nuclei inside them, experience significant mechanical stress in diverse biological processes, including contraction, migration, and adhesion. The structural stability of nuclei must therefore be maintained in order to protect genome integrity. Despite extensive knowledge on nuclear architecture and components, however, the underlying physical and molecular mechanisms remain largely unknown. We address this by subjecting isolated human cell nuclei to microneedle-based quantitative micromanipulation with a series of biochemical perturbations of the chromatin. We find that the mechanical rigidity of nuclei depends on the continuity of the nucleosomal fiber and interactions between nucleosomes. Disrupting these chromatin features by varying cation concentration, acetylating histone tails, or digesting linker DNA results in loss of nuclear rigidity. In contrast, the levels of key chromatin assembly factors, including cohesin, condensin II, and CTCF, and a major nuclear envelope protein, lamin, are unaffected. Together with in situ evidence using living cells and a simple mechanical model, our findings reveal a chromatin-based regulation of the nuclear mechanical response and provide insight into the significance of local and global chromatin structures, such as those associated with interdigitated or melted nucleosomal fibers.

scholarly journals Effect of cellular rearrangement time delays on the rheology of vertex models for confluent tissues

2021 ◽  
Author(s):  
Gonca Erdemci-Tandogan ◽  
M. Lisa Manning
Keyword(s):  
Delay Time ◽  
Cell Shape ◽  
Large Scale ◽  
Molecular Mechanisms ◽  
Tissue Mechanics ◽  
Tissue Response ◽  
Biological Processes ◽  
Convergent Extension ◽  
Vertex Models ◽  
Long Time

Large-scale tissue deformation during biological processes such as morphogenesis requires cellular rearrangements. The simplest rearrangement in confluent cellular monolayers involves neighbor exchanges among four cells, called a T1 transition, in analogy to foams. But unlike foams, cells must execute a sequence of molecular processes, such as endocytosis of adhesion molecules, to complete a T1 transition. Such processes could take a long time compared to other timescales in the tissue. In this work, we incorporate this idea by augmenting vertex models to require a fixed, finite time for T1 transitions, which we call the “T1 delay time”. We study how variations in T1 delay time affect tissue mechanics, by quantifying the relaxation time of tissues in the presence of T1 delays and comparing that to the cell-shape based timescale that characterizes fluidity in the absence of any T1 delays. We show that the molecular-scale T1 delay timescale dominates over the cell shape-scale collective response timescale when the T1 delay time is the larger of the two. We extend this analysis to tissues that become anisotropic under convergent extension, finding similar results. Moreover, we find that increasing the T1 delay time increases the percentage of higher-fold coordinated vertices and rosettes, and decreases the overall number of successful T1s, contributing to a more elastic-like – and less fluid-like – tissue response. Our work suggests that molecular mechanisms that act as a brake on T1 transitions could stiffen global tissue mechanics and enhance rosette formation during morphogenesis.

scholarly journals Orange Fluorescent Proteins: Filling the Spectral Gap

2014 ◽  
Vol 70 (a1) ◽  
pp. C1670-C1670
Author(s):  
Sergei Pletnev ◽  
Daria Shcherbakova ◽  
Oksana Subach ◽  
Vladimir Malashkevich ◽  
Steven Almo ◽  
...  
Keyword(s):  
In Vivo Imaging ◽  
Spectral Properties ◽  
Molecular Mechanisms ◽  
Fluorescent Protein ◽  
Fluorescent Proteins ◽  
Stokes Shift ◽  
Emission Wavelength ◽  
Microscopy Imaging ◽  
Large Stokes Shift

Fluorescent proteins (FPs) have become valuable tools for molecular biology, biochemistry, medicine, and cancer research. Starting from parent green fluorescent protein (GFP), most challenging task of the FPs studies was the development of FPs with longer excitation/emission wavelength. This pursuit was motivated by advantages of so-called red-shifted FPs, namely, lower background of cellular autofluorescence in microscopy, lower light scattering and reduced tissue absorbance of longer wavelengths for in vivo imaging. In addition to FPs with regular spectral properties, there are proteins of other types available, including FPs with a large Stokes shift and photoconvertible FPs. These special kinds of FPs have become useful in super-resolution microscopy, imaging of enzyme activities, protein-protein interactions, photolabeling, and in vivo imaging. According to their emission wavelength, red-shifted FPs could be divided in the following groups: 520-540 nm yellow FPs (YFPs), 540-570 nm orange FPs (OFPs), 570-620 nm red FPs (RFPs), and > 620 nm far-RFPs. Red shift of the excitation/emission bands of these FPs is predominantly achieved by extension of the conjugated system of the chromophore and its protonation/deprotonation. The variety of spectral properties of FPs (excitation and emission wavelength, quantum yield, brightness, photo- and pH- stability, photoconversion, large Stokes shift, etc) results from the different chromophore structures and its interactions with surrounding amino acid residues. In this work we focus on structural studies and molecular mechanisms of FPs with orange emission.

scholarly journals Cold Atmospheric Plasma Cancer Treatment, a Critical Review

2021 ◽  
Vol 11 (16) ◽  
pp. 7757
Author(s):  
Dayun Yan ◽  
Alisa Malyavko ◽  
Qihui Wang ◽  
Li Lin ◽  
Jonathan H. Sherman ◽  
...  
Keyword(s):  
Cancer Treatment ◽  
Molecular Mechanisms ◽  
Critical Evaluation ◽  
Atmospheric Plasma ◽  
Physical Factors ◽  
Atmospheric Conditions ◽  
Cold Atmospheric Plasma ◽  
Anti Cancer ◽  
Biological Impacts ◽  
Indirect Treatment

Cold atmospheric plasma (CAP) is an ionized gas, the product of a non-equilibrium discharge at atmospheric conditions. Both chemical and physical factors in CAP have been demonstrated to have unique biological impacts in cancer treatment. From a chemical-based perspective, the anti-cancer efficacy is determined by the cellular sensitivity to reactive species. CAP may also be used as a powerful anti-cancer modality based on its physical factors, mainly EM emission. Here, we delve into three CAP cancer treatment approaches, chemically based direct/indirect treatment and physical-based treatment by discussing their basic principles, features, advantages, and drawbacks. This review does not focus on the molecular mechanisms, which have been widely introduced in previous reviews. Based on these approaches and novel adaptive plasma concepts, we discuss the potential clinical application of CAP cancer treatment using a critical evaluation and forward-looking perspectives.

scholarly journals Elucidating the Biomechanics of Leukocyte Transendothelial Migration by Quantitative Imaging

2021 ◽  
Vol 9 ◽  
Author(s):  
Amy B. Schwartz ◽  
Obed A. Campos ◽  
Ernesto Criado-Hidalgo ◽  
Shu Chien ◽  
Juan C. del Álamo ◽  
...  
Keyword(s):  
Vascular Endothelial Cells ◽  
Inflammatory Diseases ◽  
Leukocyte Adhesion ◽  
Decisive Role ◽  
Transendothelial Migration ◽  
Physical Contact ◽  
Cell Junctions ◽  
Force Transmission ◽  
Recent Advances ◽  
Leukocyte Transendothelial Migration

Leukocyte transendothelial migration is crucial for innate immunity and inflammation. Upon tissue damage or infection, leukocytes exit blood vessels by adhering to and probing vascular endothelial cells (VECs), breaching endothelial cell-cell junctions, and transmigrating across the endothelium. Transendothelial migration is a critical rate-limiting step in this process. Thus, leukocytes must quickly identify the most efficient route through VEC monolayers to facilitate a prompt innate immune response. Biomechanics play a decisive role in transendothelial migration, which involves intimate physical contact and force transmission between the leukocytes and the VECs. While quantifying these forces is still challenging, recent advances in imaging, microfabrication, and computation now make it possible to study how cellular forces regulate VEC monolayer integrity, enable efficient pathfinding, and drive leukocyte transmigration. Here we review these recent advances, paying particular attention to leukocyte adhesion to the VEC monolayer, leukocyte probing of endothelial barrier gaps, and transmigration itself. To offer a practical perspective, we will discuss the current views on how biomechanics govern these processes and the force microscopy technologies that have enabled their quantitative analysis, thus contributing to an improved understanding of leukocyte migration in inflammatory diseases.

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