scholarly journals LIM-Nebulette Reinforces Podocyte Structural Integrity by Linking Actin and Vimentin Filaments

2020 ◽  
Vol 31 (10) ◽  
pp. 2372-2391 ◽  
Author(s):  
Xuhua Ge ◽  
Tao Zhang ◽  
Xiaoxia Yu ◽  
Alecia N. Muwonge ◽  
Nanditha Anandakrishnan ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Rho Gtpase ◽  
Focal Adhesions ◽  
Super Resolution ◽  
Actin Binding ◽  
Puromycin Aminonucleoside ◽  
Force Microscopy ◽  
Afm Indentation ◽  
Atomic Force ◽  
Key Aspects

BackgroundMaintenance of the intricate interdigitating morphology of podocytes is crucial for glomerular filtration. One of the key aspects of specialized podocyte morphology is the segregation and organization of distinct cytoskeletal filaments into different subcellular components, for which the exact mechanisms remain poorly understood.MethodsCells from rats, mice, and humans were used to describe the cytoskeletal configuration underlying podocyte structure. Screening the time-dependent proteomic changes in the rat puromycin aminonucleoside–induced nephropathy model correlated the actin-binding protein LIM-nebulette strongly with glomerular function. Single-cell RNA sequencing and immunogold labeling were used to determine Nebl expression specificity in podocytes. Automated high-content imaging, super-resolution microscopy, atomic force microscopy (AFM), live-cell imaging of calcium, and measurement of motility and adhesion dynamics characterized the physiologic role of LIM-nebulette in podocytes.ResultsNebl knockout mice have increased susceptibility to adriamycin-induced nephropathy and display morphologic, cytoskeletal, and focal adhesion abnormalities with altered calcium dynamics, motility, and Rho GTPase activity. LIM-nebulette expression is decreased in diabetic nephropathy and FSGS patients at both the transcript and protein level. In mice, rats, and humans, LIM-nebulette expression is localized to primary, secondary, and tertiary processes of podocytes, where it colocalizes with focal adhesions as well as with vimentin fibers. LIM-nebulette shRNA knockdown in immortalized human podocytes leads to dysregulation of vimentin filament organization and reduced cellular elasticity as measured by AFM indentation.ConclusionsLIM-nebulette is a multifunctional cytoskeletal protein that is critical in the maintenance of podocyte structural integrity through active reorganization of focal adhesions, the actin cytoskeleton, and intermediate filaments.

Material Property Characterization of Costal Cartilage Using AFM Indentation

2009 ◽  
Author(s):  
S. Tripathy ◽  
E. J. Berger
Keyword(s):  
Material Characterization ◽  
Costal Cartilage ◽  
Indentation Modulus ◽  
Hertz Contact ◽  
Force Microscopy ◽  
Afm Indentation ◽  
Atomic Force ◽  
Macro Scale ◽  
Property Characterization

Costal cartilage is one of the load bearing tissues of the rib cage. Literature on the material characterization of the costal cartilage is limited. Atomic force microscopy has been extremely successful in characterizing the elastic properties of articular cartilage, but no studies have been published on costal cartilage. In this study AFM indentations on human costal cartilage were performed and compared with macro scale indentation data. Spherical beaded tips of three sizes were used for the AFM indentations. The Hertz contact model for spherical indenter was used to analyze the data and obtain the Young’s modulus. The costal cartilage was found to be almost linearly elastic till 600 nm of indentation depth. It was also found that the modulus values decreased with the distance from the junction. The modulus values from macro indentations were found to be 2-fold larger than the AFM indentation modulus.

scholarly journals Atomic Force Microscopy Applied to Atopic Dermatitis Study

2021 ◽  
Vol 18 (4) ◽  
pp. 21-28
Author(s):  
Simona Maria Ţîrcă ◽  
Ion Ţîrcă ◽  
Marius Sorin Ciontea ◽  
Florin Dumitru Mihălţan
Keyword(s):  
Atomic Force Microscopy ◽  
Atopic Dermatitis ◽  
Structural Integrity ◽  
Clinical Investigation ◽  
Normal Skin ◽  
Skin Lesions ◽  
Force Microscopy ◽  
Atomic Force ◽  
Child Patient ◽  
Surface Morphologies

Abstract Atopic dermatitis (AD)-the commonest inflammatory skin disease affects up to 25% of children and 2% to 5% of adults. Methods of the diagnostic provide expanded recommendations founded on available evidence. Morphological evaluation remains a principal feature of clinical investigation and the main criteria of diagnosis. Methods. We collected normal and affected skin from a 6-month child patient who was diagnosed through dermatologic examination. Clinical characteristics and the diagnosis of atopic dermatitis were in accordance with Hanifin and Rajka criteria. Morphology and structural integrity were investigated by Atomic Force Microscopy. Results. Optical and topography images indicate that in the case of AD skin lesions the cuticle structure was severely damaged and distorted with the flattening and grading of the plates, which have an irregular appearance. From the surface morphologies of the samples, we demonstrate that the shape of the corneocytes, with granular and elongated appearance, specific to normal skin is transformed by AD into broken and collapsed plates with discontinuous appearance. Conclusions. In the initial diagnosis of AD changes of the skin properties can be an indicator. Hanifin and Rajka criteria together with Atomic Force Microscopy can be a useful and necessary technique diagnosing cases of atopic dermatitis.

scholarly journals Recent Applications of Advanced Atomic Force Microscopy in Polymer Science: A Review

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1142 ◽  
Author(s):  
Phuong Nguyen-Tri ◽  
Payman Ghassemi ◽  
Pascal Carriere ◽  
Sonil Nanda ◽  
Aymen Amine Assadi ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Chemical Characterization ◽  
Super Resolution ◽  
Polymeric Materials ◽  
Polymer Materials ◽  
Polymer Science ◽  
Force Microscopy ◽  
Atomic Force ◽  
Nanoscale Characterization

Atomic force microscopy (AFM) has been extensively used for the nanoscale characterization of polymeric materials. The coupling of AFM with infrared spectroscope (AFM-IR) provides another advantage to the chemical analyses and thus helps to shed light upon the study of polymers. This paper reviews some recent progress in the application of AFM and AFM-IR in polymer science. We describe the principle of AFM-IR and the recent improvements to enhance its resolution. We also discuss the latest progress in the use of AFM-IR as a super-resolution correlated scanned-probe infrared spectroscopy for the chemical characterization of polymer materials dealing with polymer composites, polymer blends, multilayers, and biopolymers. To highlight the advantages of AFM-IR, we report several results in studying the crystallization of both miscible and immiscible blends as well as polymer aging. Finally, we demonstrate how this novel technique can be used to determine phase separation, spherulitic structure, and crystallization mechanisms at nanoscales, which has never been achieved before. The review also discusses future trends in the use of AFM-IR in polymer materials, especially in polymer thin film investigation.

A high-speed atomic force microscopy with super resolution based on path planning scanning

2020 ◽  
Vol 213 ◽  
pp. 112991
Author(s):  
Yinan Wu ◽  
Yongchun Fang ◽  
Chao Wang ◽  
Cunhuan Liu ◽  
Zhi Fan
Keyword(s):  
Atomic Force Microscopy ◽  
Path Planning ◽  
High Speed ◽  
Super Resolution ◽  
Force Microscopy ◽  
Atomic Force

scholarly journals How did correlative atomic force microscopy and super-resolution microscopy evolve in the quest for unravelling enigmas in biology?

Nanoscale ◽  
2021 ◽  
Author(s):  
Adelaide Miranda ◽  
Ana I. Gómez-Varela ◽  
Andreas Stylianou ◽  
Liisa M. Hirvonen ◽  
Humberto Sánchez ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Super Resolution ◽  
Force Microscopy ◽  
Atomic Force ◽  
Microscopy Techniques ◽  
Super Resolution Microscopy ◽  
Detailed Picture

This review provides a detailed picture of the innovative efforts to combine atomic force microscopy and different super-resolution microscopy techniques to elucidate biological questions.

scholarly journals Direct observation of dynamic force propagation between focal adhesions of cells on microposts by atomic force microscopy

2011 ◽  
Vol 99 (26) ◽  
pp. 263703 ◽  
Author(s):  
Akinori Okada ◽  
Yusuke Mizutani ◽  
Agus Subagyo ◽  
Hirotaka Hosoi ◽  
Motonori Nakamura ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Direct Observation ◽  
Focal Adhesions ◽  
Dynamic Force ◽  
Force Microscopy ◽  
Atomic Force ◽  
Force Propagation

Analysis of Indentation: Implications for Measuring Mechanical Properties With Atomic Force Microscopy

1999 ◽  
Vol 121 (5) ◽  
pp. 462-471 ◽  
Author(s):  
K. D. Costa ◽  
F. C. P. Yin
Keyword(s):  
Indentation Depth ◽  
Constitutive Law ◽  
Elastic Materials ◽  
Force Microscopy ◽  
Linear Elastic ◽  
Afm Indentation ◽  
Atomic Force ◽  
Afm Probe ◽  
Nonlinear Elastic ◽  
Indenter Geometry

Indentation using the atomic force microscope (AFM) has potential to measure detailed micromechanical properties of soft biological samples. However, interpretation of the results is complicated by the tapered shape of the AFM probe tip, and its small size relative to the depth of indentation. Finite element models (FEMs) were used to examine effects of indentation depth, tip geometry, and material nonlinearity and heterogeneity on the finite indentation response. Widely applied infinitesimal strain models agreed with FEM results for linear elastic materials, but yielded substantial errors in the estimated properties for nonlinear elastic materials. By accounting for the indenter geometry to compute an apparent elastic modulus as a function of indentation depth, nonlinearity and heterogeneity of material properties may be identified. Furthermore, combined finite indentation and biaxial stretch may reveal the specific functional form of the constitutive law—a requirement for quantitative estimates of material constants to be extracted from AFM indentation data.

scholarly journals Membrane bending begins at any stage of clathrin-coat assembly and defines endocytic dynamics

2017 ◽  
Author(s):  
Brandon L. Scott ◽  
Kem A. Sochacki ◽  
Shalini T. Low-Nam ◽  
Elizabeth M. Bailey ◽  
QuocAhn Luu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Total Internal Reflection ◽  
Super Resolution ◽  
Force Microscopy ◽  
Atomic Force ◽  
Fundamental Biological Process ◽  
Resolution Imaging ◽  
Membrane Bending ◽  
The Relationship ◽  
Spherical Vesicles

Summary ParagraphClathrin-mediated endocytosis internalizes membrane from the cell surface by reshaping flat regions of membrane into spherical vesicles(1, 2). The relationship between membrane bending and clathrin coatomer assembly has been inferred from electron microscopy and structural biology, without directly visualization of membrane bending dynamics (3–6). This has resulted in two distinct and opposing models for how clathrin bends membrane (7–10). Here, polarized Total Internal Reflection Fluorescence microscopy was improved and combined with electron microscopy, atomic force microscopy, and super-resolution imaging to measure membrane bending during endogenous clathrin and dynamin assembly in living cells. Surprisingly, and not predicted by either model, the timing of membrane bending was variable relative to clathrin assembly. Approximately half of the time, membrane bending occurs at the start of clathrin assembly, in the other half, the onset of membrane bending lags clathrin arrival, and occasionally completely assembled flat clathrin transitions into a pit. Importantly, once the membrane bends, the process proceeds to scission with similar timing. We conclude that the pathway of coatomer formation is versatile and can bend the membrane during or after the assembly of the clathrin lattice. These results highlight the heterogeneity in this fundamental biological process, and provide a more complete nanoscale view of membrane bending dynamics during endocytosis.

Sign in / Sign up

Export Citation Format

Share Document