Mechanical properties measured by atomic force microscopy define health biomarkers in ageing C. elegans

Abstract

Genetic and environmental factors are key drivers regulating organismal lifespan but how these impact healthspan is less well understood. Techniques capturing biomechanical properties of tissues on a nano-scale level are providing new insights into disease mechanisms. Here, we apply Atomic Force Microscopy (AFM) to quantitatively measure the change in biomechanical properties associated with ageing Caenorhabditis elegans in addition to capturing high-resolution topographical images of cuticle senescence. We show that distinct dietary restriction regimes and genetic pathways that increase lifespan lead to radically different healthspan outcomes. Hence, our data support the view that prolonged lifespan does not always coincide with extended healthspan. Importantly, we identify the insulin signalling pathway in C. elegans and interventions altering bacterial physiology as increasing both lifespan and healthspan. Overall, AFM provides a highly sensitive technique to measure organismal biomechanical fitness and delivers an approach to screen for healthimproving conditions, an essential step towards healthy ageing.

C. elegans Apical Extracellular Matrices Shape Epithelia

“…The adult C. elegans cuticle must remain intact throughout the organism’s two weeks of adulthood, even as C. elegans continues to grow in both length and width. Over the course of one week of adulthood, cuticle structure becomes irregular and its stiffness declines [ 166 ]. Some cuticle collagens gradually decrease in expression level throughout adulthood, and excess expression of specific cuticle collagens throughout development can prolong life [ 167 ].…”

The cellular mechanobiology of aging: from biology to mechanics

“…29 In addition to cellular analysis, AFM is also a highly sensitive technique to measure the organismal biomechanical properties of aging Caenorhabditis elegans and Drosophila. 67,155 In vivo AFM mechanical measurement revealed mechanical degradation associated with aging, and cuticle senescence and stiffness can be used as biomarkers of aging and health span. Overall, AFM has been extensively applied in aging mechanobiology research and has discovered various age-associated changes in cell mechanical properties.…”

“…AFM uses a vertical microcantilever to measure the stiffness and force of the cell to study the correlation between the changing cellular mechanics and aging. 11,29,31,63,155 Owing to its extremely high detection resolution, AFM can map subcellular mechanical properties and measure the different rigidities of the nucleus, cytoplasm, and cell edge. 29,98 AFM measurement allows for quantitation of the cellular cytoskeleton and demonstrates that older human epithelial cells have a denser and thicker cytoskeleton than younger cells.…”

“…Overall, AFM has been extensively applied in aging mechanobiology research and has discovered various age-associated changes in cell mechanical properties. 31,155,156 Single-molecule Förster resonance energy transfer microscopy for visualizing the activation of mechanotransduction signaling Förster resonance energy transfer (FRET)-based molecular sensors have been widely used for dynamic monitoring of mechanosensitive molecular activities in the cell (Fig. 4B).…”

Transcriptome analysis ofCaenorhabditis eleganslacking heme peroxidase SKPO-1 reveals an altered response toEnterococcus faecalis

“…In particular, we saw significant changes in gene expression related to cuticle formation and a failure to upregulate genes encoding neurosensory guanylyl cyclases on E. faecalis . Additional functional characterization of the skpo-1 cuticle defect was performed using Hoechst staining and atomic force microscopy (AFM), a technique recently adapted to C. elegans to acquire topographical information under physiological conditions at nanometer resolution ( Essmann et al 2017 , 2020 ). Overall, our analysis identified genes and structural features that might underlie skpo-1 animal’s morphological defects as well as its sensitivity to a human pathogen.…”