scholarly journals Fluorogenic DNase Sensor Reveals Ubiquitous DNase Activity in Podosomes and Invadopodia

2020 ◽  
Author(s):  
Kaushik Pal ◽  
Yuanchang Zhao ◽  
Yongliang Wang ◽  
Xuefeng Wang
Keyword(s):  
Physiological Role ◽  
Cell Types ◽  
Dnase Activity ◽  
Fluorescence Signal ◽  
Matrix Remodeling ◽  
Substrate Interface ◽  
Cell Functions ◽  
Double Stranded Dna ◽  
Cell Substrate ◽  
Degradative Enzymes

Podosomes and invadopodia, collectively termed invadosomes, are important adhesive and degradative units formed in macrophages, osteoclasts, dendritic cells, cancer cells, and many other cell types. Invadosomes are well known for recruiting proteases that degrade matrix proteins and facilitate cell invasion. In contrast to the extensively studied proteases, another important class of degradative enzymes, DNase, remains uninvestigated and in fact, unknown in invadosomes. Using surface nuclease sensor (SNS), which reports deoxyribonuclease (DNase) activity on the cell membrane by fluorescence signal, we revealed that invadosomes, regardless of cell types or species, universally recruit DNase and readily degrade extracellular double-stranded DNA (dsDNA). We identified the recruited DNase as GPI-anchored membrane protein DNase X which functions locally at the cell-substrate interface and is co-localized with the actin cores of the invadosomes. DNase recruitment is highly consistent and rapid in invadosomes. Co-imaging of F-actin and DNase activity shows that 46-86% invadosomes (dependent on cell types) have associated DNase activities. Time series imaging shows that DNase becomes active within a minute after the actin nucleation, functioning concomitantly with protease activity in podosomes but preceding it in invadopodia. Overall, this discovery suggests a richer arsenal of degradative enzymes in invadosomes at the cell-substrate interface. This work would likely prompt more studies to investigate DNase in invadosomes, in particular, to understand the physiological role of invadosome-associated membrane DNase in cell functions such as immune response, cell migration, matrix remodeling, etc.

scholarly journals Ubiquitous membrane-bound DNase activity in podosomes and invadopodia

2021 ◽  
Vol 220 (7) ◽  
Author(s):  
Kaushik Pal ◽  
Yuanchang Zhao ◽  
Yongliang Wang ◽  
Xuefeng Wang
Keyword(s):  
Cell Types ◽  
Dnase Activity ◽  
Immunological Function ◽  
Membrane Structures ◽  
Bacterial Dna ◽  
Double Stranded Dna ◽  
Major Class ◽  
Degradative Enzymes ◽  
Membrane Bound ◽  
First Time

Podosomes and invadopodia, collectively termed invadosomes, are adhesive and degradative membrane structures formed in many types of cells and are well known for recruiting various proteases. However, another major class of degradative enzymes, deoxyribonuclease (DNase), remains unconfirmed and not studied in invadosomes. Here, using surface-immobilized nuclease sensor (SNS), we demonstrated that invadosomes recruit DNase to their core regions, which degrade extracellular double-stranded DNA. We further identified the DNase as GPI-anchored membrane-bound DNase X. DNase recruitment is ubiquitous and consistent in invadosomes of all tested cell types. DNase activity exhibits within a minute after actin nucleation, functioning concomitantly with protease in podosomes but preceding it in invadopodia. We further showed that macrophages form DNase-active podosome rosettes surrounding bacteria or micropatterned antigen islets, and the podosomes directly degrade bacterial DNA on a surface, exhibiting an apparent immunological function. Overall, this work reports DNase in invadosomes for the first time, suggesting a richer arsenal of degradative enzymes in invadosomes than known before.

scholarly journals Calcium oscillations in wounded fibroblast monolayers are spatially regulated through substrate mechanics

2017 ◽  
Author(s):  
Josephine Lembong ◽  
Benedikt Sabass ◽  
Howard A. Stone
Keyword(s):  
Physiological Role ◽  
Traction Force ◽  
Cell Types ◽  
Cytosolic Calcium ◽  
Skin Wound ◽  
Calcium Oscillations ◽  
Force Microscopy ◽  
Substrate Rigidity ◽  
Cell Substrate ◽  
Multicellular Organisms

ABSTRACTThe maintenance of tissue integrity is essential for the life of multicellular organisms. Healing of a skin wound is a paradigm for how various cell types localize and repair tissue perturbations in an orchestrated fashion. To investigate biophysical mechanisms associated with wound localization, we focus on a model system consisting of a fibroblast monolayer on an elastic substrate. We find that the creation of an edge in the monolayer causes cytosolic calcium oscillations throughout the monolayer. The oscillation frequency increases with cell density, which shows that wound-induced calcium oscillations occur collectively. Inhibition of myosin II reduces the number of oscillating cells, demonstrating a coupling between actomyosin activity and calcium response. The spatial distribution of oscillating cells depends on the stiffness of the substrate. For soft substrates with a Young’s modulus E ~ 360 Pa, oscillations occur on average within 0.2 mm distance from the wound edge. Increasing substrate stiffness leads to an average localization of oscillations away from the edge (up to ~0.6 mm). In addition, we use traction force microscopy to determine stresses between cells and substrate. We find that an increase of substrate rigidity leads to a higher traction magnitude. For E < ~2 kPa, the traction magnitude is strongly concentrated at the monolayer edge, while for E > ~8 kPa, traction magnitude is on average almost uniform beneath the monolayer. Thus, the spatial occurrence of calcium oscillations correlates with the cell-substrate traction. Overall, the experiments with fibroblasts demonstrate a collective, chemomechanical localization mechanism at the edge of a wound with a potential physiological role.

Production and Analysis of High Resolution Polymer Replicas of Fibrillar Collagen

1999 ◽  
Vol 5 (S2) ◽  
pp. 398-399
Author(s):  
P. Sims ◽  
B. Todd ◽  
S. Eppell ◽  
T. Li ◽  
K. Park ◽  
...  
Keyword(s):  
Cellular Response ◽  
Physical Nature ◽  
Cell Types ◽  
Artificial Substrates ◽  
Adherent Cell ◽  
Fibrillar Collagen ◽  
New Materials ◽  
Substrate Interactions ◽  
Number Of Factors ◽  
Cell Substrate

Adherent cells generally construct the immediate substrate upon which they reside. This may occur via synthesis and secretion of new materials and/or by rearrangement and modification of existing substrate. The response of adherent cell types to an existing substrate can be influenced by a number of factors which include both the chemical and physical nature of the substrate. Cell adhesion, proliferation, differentiation and death can all be substrate dependent. Much effort has been directed toward chemical modification of substrates to regulate one or more of the parameters noted above. A significant, but somewhat smaller, degree of attention has been paid to the effects of the topography and microtopography on the cell response to substrate materials. Studies to date strongly suggest the topography is a significant factor in cell-substrate interactions. As noted above, it is most probable that both the chemistry and the structure of a substrate simultaneously influence the cellular response. However we wished to determine, particularly for artificial substrates, the role which microtopography can play in cell-substrate interactions.

Clock gene-independent daily regulation of haemoglobin oxidation in red blood cells

2021 ◽  
Author(s):  
Andrew D. Beale ◽  
Priya Crosby ◽  
Utham K. Valekunja ◽  
Rachel S. Edgar ◽  
Johanna E. Chesham ◽  
...  
Keyword(s):  
Circadian Rhythms ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Human Subjects ◽  
Developmental Regulation ◽  
Physiological Role ◽  
Cell Types ◽  
The Body

AbstractCellular circadian rhythms confer daily temporal organisation upon behaviour and physiology that is fundamental to human health and disease. Rhythms are present in red blood cells (RBCs), the most abundant cell type in the body. Being naturally anucleate, RBC circadian rhythms share key elements of post-translational, but not transcriptional, regulation with other cell types. The physiological function and developmental regulation of RBC circadian rhythms is poorly understood, however, partly due to the small number of appropriate techniques available. Here, we extend the RBC circadian toolkit with a novel biochemical assay for haemoglobin oxidation status, termed “Bloody Blotting”. Our approach relies on a redox-sensitive covalent haem-haemoglobin linkage that forms during cell lysis. Formation of this linkage exhibits daily rhythms in vitro, which are unaffected by mutations that affect the timing of circadian rhythms in nucleated cells. In vivo, haemoglobin oxidation rhythms demonstrate daily variation in the oxygen-carrying and nitrite reductase capacity of the blood, and are seen in human subjects under controlled laboratory conditions as well as in freely-behaving humans. These results extend our molecular understanding of RBC circadian rhythms and suggest they serve an important physiological role in gas transport.

scholarly journals Augmentation of Dermal Wound Healing by Adipose Tissue-Derived Stromal Cells (ASC)

2018 ◽  
Vol 5 (4) ◽  
pp. 91 ◽  
Author(s):  
Joris van Dongen ◽  
Martin Harmsen ◽  
Berend van der Lei ◽  
Hieronymus Stevens
Keyword(s):  
Extracellular Matrix ◽  
Wound Healing ◽  
Adipose Tissue ◽  
Stromal Cells ◽  
Randomized Clinical Trials ◽  
Cell Types ◽  
Matrix Remodeling ◽  
Skin Wound Healing ◽  
Dermal Wound Healing ◽  
Dermal Wound

The skin is the largest organ of the human body and is the first line of defense against physical and biological damage. Thus, the skin is equipped to self-repair and regenerates after trauma. Skin regeneration after damage comprises a tightly spatial-temporally regulated process of wound healing that involves virtually all cell types in the skin. Wound healing features five partially overlapping stages: homeostasis, inflammation, proliferation, re-epithelization, and finally resolution or fibrosis. Dysreguled wound healing may resolve in dermal scarring. Adipose tissue is long known for its suppressive influence on dermal scarring. Cultured adipose tissue-derived stromal cells (ASCs) secrete a plethora of regenerative growth factors and immune mediators that influence processes during wound healing e.g., angiogenesis, modulation of inflammation and extracellular matrix remodeling. In clinical practice, ASCs are usually administered as part of fractionated adipose tissue i.e., as part of enzymatically isolated SVF (cellular SVF), mechanically isolated SVF (tissue SVF), or as lipograft. Enzymatic isolation of SVF obtained adipose tissue results in suspension of adipocyte-free cells (cSVF) that lack intact intercellular adhesions or connections to extracellular matrix (ECM). Mechanical isolation of SVF from adipose tissue destructs the parenchyma (adipocytes), which results in a tissue SVF (tSVF) with intact connections between cells, as well as matrix. To date, due to a lack of well-designed prospective randomized clinical trials, neither cSVF, tSVF, whole adipose tissue, or cultured ASCs can be indicated as the preferred preparation procedure prior to therapeutic administration. In this review, we present and discuss current literature regarding the different administration options to apply ASCs (i.e., cultured ASCs, cSVF, tSVF, and lipografting) to augment dermal wound healing, as well as the available indications for clinical efficacy.

scholarly journals A novel method for sensor-based quantification of single/multi-cellular traction dynamics and remodeling in 3D matrices

2020 ◽  
Author(s):  
Bashar Emon ◽  
Zhengwei Li ◽  
Md Saddam Hossain Joy ◽  
Umnia Doha ◽  
Farhad Kosari ◽  
...  
Keyword(s):  
Self Assembly ◽  
Single Cells ◽  
Human Colon ◽  
Matrix Remodeling ◽  
Tissue Stiffness ◽  
Force Dynamics ◽  
Cell Functions ◽  
The Matrix ◽  
Cancer Tumor

AbstractCells in vivo generate mechanical forces (traction) on surrounding 3D extra cellular matrix (ECM) and cells. Such traction and biochemical cues may remodel the matrix, e.g. increase stiffness, which in turn influences cell functions and forces. This dynamic reciprocity mediates development and tumorigenesis. Currently, there is no method available to directly quantify single cell traction and matrix remodeling in 3D. Here, we introduce a method to fulfil this long-standing need. We developed a high-resolution microfabricated sensor which hosts a 3D cell-ECM tissue formed by self-assembly. It measures cell forces and tissue-stiffness and can apply mechanical stimulation to the tissue. We measured single and multicellular force dynamics of fibroblasts (3T3), human colon (FET) and lung (A549) cancer cells and cancer associated fibroblasts (CAF05) with 1 nN resolution. Single cells show significant force fluctuations in 3D. FET/CAF co-culture system, mimicking cancer tumor microenvironment, increased tissue stiffness by 3 times within 24 hours.

scholarly journals Silencing of Unintegrated Retroviral DNAs

Viruses ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2248
Author(s):  
Stephen P. Goff
Keyword(s):  
Embryonic Stem ◽  
Cell Types ◽  
Retroviral Infection ◽  
Double Stranded Dna ◽  
Immunodeficiency Virus ◽  
Unintegrated Dna ◽  
Potential Impact ◽  
Leukemia Viruses ◽  
Present Understanding

Retroviral infection delivers an RNA genome into the cytoplasm that serves as the template for the synthesis of a linear double-stranded DNA copy by the viral reverse transcriptase. Within the nucleus this linear DNA gives rise to extrachromosomal circular forms, and in a key step of the life cycle is inserted into the host genome to form the integrated provirus. The unintegrated DNA forms, like those of DNAs entering cells by other means, are rapidly loaded with nucleosomes and heavily silenced by epigenetic histone modifications. This review summarizes our present understanding of the silencing machinery for the DNAs of the mouse leukemia viruses and human immunodeficiency virus type 1. We consider the potential impact of the silencing on virus replication, on the sensing of the virus by the innate immune system, and on the formation of latent proviruses. We also speculate on the changeover to high expression from the integrated proviruses in permissive cell types, and briefly consider the silencing of proviruses even after integration in embryonic stem cells and other developmentally primitive cell types.

scholarly journals RHBDL4 protects against endoplasmic reticulum stress by regulating the morphology and distribution of ER sheets

2021 ◽  
Author(s):  
Viorica Liebe Lastun ◽  
Matthew Freeman
Keyword(s):  
Cell Cycle ◽  
Endoplasmic Reticulum ◽  
Endoplasmic Reticulum Stress ◽  
Er Stress ◽  
Liver Steatosis ◽  
Physiological Role ◽  
Cell Types ◽  
Rhomboid Protease ◽  
Rapid Changes

In metazoans, the architecture of the endoplasmic reticulum (ER) differs between cell types, and undergoes major changes through the cell cycle and according to physiological needs. Although much is known about how the different ER morphologies are generated and maintained, especially the ER tubules, how context dependent changes in ER shape and distribution are regulated and the factors involved are less characterized. Here, we show that RHBDL4, an ER-resident rhomboid protease, modulates the shape and distribution of the ER, especially under conditions that require rapid changes in the ER sheet distribution, including ER stress. RHBDL4 interacts with CLIMP-63, a protein involved in ER sheet stabilisation, and with the cytoskeleton. Mice lacking RHBDL4 are sensitive to ER stress and develop liver steatosis, a phenotype associated with unresolved ER stress. Our data introduce a new physiological role of RHBDL4 and also imply that this function does not require its enzymatic activity.

scholarly journals Ca(2+) Oscillations and Its Transporters in Mesenchymal Stem Cells

2010 ◽  
pp. 323-329 ◽  
Author(s):  
B Ye
Keyword(s):  
Tissue Engineering ◽  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Replacement Therapy ◽  
Cell Types ◽  
Cell Replacement Therapy ◽  
Cell Replacement ◽  
Cell Functions ◽  
The Past ◽  
Intracellular Ca

Intracellular free Ca(2+) is one of important biological signals regulating a number of cell functions. It has been discussed widely and extensively in several cell types during the past two decades. Attention has been paid to the Ca2+ transportation in mesenchymal stem cells in recent years as mesenchymal stem cells have gained considerable interest due to their potential for cell replacement therapy and tissue engineering. In this paper, roles of intracellular Ca(2+) oscillations and its transporters in mesenchymal stem cells have been reviewed.

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