ARTICLE | doi:10.20944/preprints202110.0276.v1
Subject: Life Sciences, Biotechnology Keywords: Mesenchymal stem cells; collagen type I; remodeling; oxidation
Online: 19 October 2021 (12:19:16 CEST)
Abstract: The effect of collagen type 1 (Col I) oxidation on Adipose Tissue-Derived Mesenchymal Stem Cells (ADMSCs) remodeling is described as a model for acute oxidative stress. Morphologically, remodeling was presented by a mechanical rearrangement of adsorbed FITC-Col I and a trend for its organization in a fibril-like pattern - a process strongly abrogated in oxidized samples, but without visible changes in cell morphology. The cellular proteolytic activity was quantified in multiple samples utilizing fluorescence de-quenching (FRET effect). In the presence of ADMSCs a significant increase of native FITC-Col I fluorescence was observed, almost absent in the oxidized samples. Parallel studies in cell-free systems confirmed the enzymatic de-quenching of native FITC-Col I by Clostridial collagenase, again showing significant inhibition in oxidized samples. The structural changes in the oxidized Col I was further studied by Differential Scanning Calorimetry: an additional endotherm at 33.6°C along with the typical for native Col I at 40.5°C with sustained enthalpy (∆H) was observed in oxidized samples. Collectively, it has been evidenced that remodeling of Col I by ADMSCs is altered upon oxidation due to the intrinsic changes in the protein structure, thus presenting a novel mechanism for the control of stem cells' behavior toward collagen.
ARTICLE | doi:10.20944/preprints202208.0298.v1
Subject: Medicine & Pharmacology, Other Keywords: Adipose tissue-derived mesenchymal stem cell; collagen type I; EGCG; oxidation; remodeling
Online: 17 August 2022 (04:11:29 CEST)
Mesenchymal stem cells (MSCs) are involved in the process of extracellular matrix (ECM) remodeling where collagens play a pivotal role. We recently demonstrated that the remodeling of adsorbed collagen type I might be disordered upon oxidation following its fate in the presence of human adipose-derived MSC (ADMSCs). With the present study, we intended to learn more about the effect of polyphenolic antioxidant Epigallocatechin gallate (EGCG) attempting to mimic the conditions of oxidative stress in vivo and its putative prevention by antioxidants. Collagen Type I was isolated from mouse tail tendon (MTC) and labeled with FITC before oxidizing according to Fe2+/H2O2 protocol. FITC-collagen remodeling by ADMSC was assessed morphologically before and after EGCG pretreatment and confirmed via detailed morphometry analysis measuring the anisotropy index (AI) and fluorescence intensity (FI) in selected regions of interest (ROI), namely: outside the cells; over the cells and central (nuclear perinuclear) region, whereas the pericellular proteolytic activity was measured by de-quenching of fluorescent collagen probes (FRET effect). Here we provide morphological evidence that MTC undergoes significant reorganization by the adhering ADMSC along with the substantial activation of pericellular proteolysis, and further confirm that both processes are suppressed upon collagen oxidation. An important observation was that this abrogated remodeling cannot be prevented by the EGCG pretreatment. Conversely, the detailed morphometry analysis showed that oxidized FITC-collagen rather tends to accumulate beneath the cells and around the cell’s nuclei suggesting the activation of alternative routes for its removal, such as internalization and/or transcytosis. Morphometry analysis also revealed that both processes are supported by EGCG pretreatment.