Chitosan Treatment Delays the Induction of Senescence in Human Foreskin Fibroblast Strains

Effect of Chitosan on Synovial Membrane Derived Cells and Anterior Cruciate Ligament Fibroblasts

Previously, chitosan reduces the senescence-related phenotypes in human foreskin fibroblasts through the transforming growth factor beta (TGF-β) pathway, and enhances the proliferation and migration capabilities of these cells are demonstrated. In this study, we examined whether the senescence-delaying effect of chitosan could be applied to primary knee-related fibroblasts, such as human synovial membrane derived cells (SCs) and anterior cruciate ligament fibroblasts (ACLs). These two types of cells were obtained from donors who needed ACL reconstruction or knee replacement. We found that chitosan treatment effectively reduced aging-associated β-galactosidase (SA-β-gal)-positive cells, downregulated the expression of senescence-related proteins pRB and p53, and enhanced the 5-bromo-2'-deoxyuridine (BrdU) incorporation ability of SCs and ACLs. Moreover, chitosan could make SCs secret more glycosaminoglycans (GAGs) and produce type I collagen. The ability of ACLs to close the wound was also enhanced, and the TGF-β and alpha smooth muscle actin (αSMA) protein expression decreased after chitosan treatment. In summary, chitosan not only delayed the senescence but also enhanced the functions of SCs and ACLs, which is beneficial to the application of chitosan in cell expansion in vitro and cell therapy.

Probing cell metabolism on insulin like growth factor(IGF)-1/tumor necrosis factor(TNF)-α and chargeable polymers co-immobilized conjugates

Cell culturing on different synthetic biomaterials would reprogram cell metabolism for adaption to their living conditions because such alterations in cell metabolism were necessary for cellular functions on them. Here we used metabolomics to uncover metabolic changes when liver cells were cultured on insulin-like growth factor (IGF)/tumor necrosis factor-α (TNF-α) and chargeable polymers co-modified biomaterials with the aim to explain their modulating effects on cell metabolism. The results showed that cell metabolism on IGF-1/TNF-α co-immobilized conjugates was significantly regulated according to their scatterings on the score plot of principal component analysis. Specifically, cell metabolisms were reprogrammed to the higher level of pyrimidine metabolism, β-alanine metabolism, and pantothenate and CoA biosynthesis, and the lower level of methionine salvage pathway in order to promote cell growth on IGF/TNF-α co-modified surface. Furthermore, cell senescence on PSt-PAAm-IGF/TNF-α surface was delayed through the regulation of branch amino acid metabolism and AMPK signal pathway. The research showed that metabolomics had great potential to uncover the molecular interaction between biomaterials and seeded cells, and provide the insights about cell metabolic reprogramming on IGF/TNF-α co-modified conjugates for cell growth.

Ag@MOF-loaded chitosan nanoparticle and polyvinyl alcohol/sodium alginate/chitosan bilayer dressing for wound healing applications

In this paper, Ag-Metal-organic framework loaded chitosan nanoparticles (0.1%Ag@MOF/1.5%CSNPs) and polyvinyl alcohol/sodium alginate/chitosan (PACS) were used as the upper and lower layers to successfully prepare a bilayer composite dressing for wound healing. The performance of bilayer dressing was evaluated. The lower layer (PACS) had uniform pore size distribution, good water retention, swelling, water vapor permeability, and biocompatibility while PACS had almost no antibacterial activity. The upper layer (Ag@MOF/CSNPs) possessed excellent antibacterial activity and poor biocompatibility. As the upper layer, it can avoid direct contact with the skin and inhibit microbial invasion. In addition, the bilayer can adhere to a large number of red blood cells and platelets, promoting blood coagulation and cell proliferation. Ag@MOF, CSNPs, Ag@MOF/CSNPs and bilayer showed antibacterial activity in ascending order, due to the synergistic antibacterial action of the upper and lower layer. In vivo evaluation showed that both bilayer and PACS could significantly accelerate the wound healing, and the bilayer dressing showed more complete re-epithelialization with less inflammatory cells. In summary, this new bilayer composite is an ideal dressing for accelerating wound healing.

Core/shell multicellular spheroids on chitosan as in vitro 3D coculture tumor models

An ideal in vitro drug screening model is important for the drug development. In addition to monoculture systems, 3 dimensional (3D) coculture systems are extensively used to simulate the in vivo tumor microenvironment as cell-cell and cell-extracellular matrix interactions within the tumor tissues can be mimicked. In this study, in vitro 3D suspension coculture multicellular spheroids with core/shell cell distribution were developed on chitosan-coated surfaces. Based on the characteristic of chitosan inhibiting cell adhesion, SW620 (colon cancer cell line), 3A6 (mesenchymal stem-like cell line) and Hs68 (foreskin fibroblast line) cells could aggregate to form 3D coculture spheroids with intimate cell contacts. When cells were cocultured on chitosan, 3A6 and Hs68 cells always located in the core of spheroids and were completely enveloped by SW620 cells due to their N-cadherin protein expression following the differential adhesion hypothesis. The core cells could be the feeder layers to stimulate the shell SW620 cells to enhance their mitochondria activity. Moreover, 3D coculture core/shell multicellular spheroids could enhance the resistance of SW620 cells against the cytotoxicity effect of chemotherapy drugs. To sum up, based on the specificity of the core/shell coculture multicellular spheroids, a novel in vitro tumor model was proposed in this study.

CD44 expression trends of mesenchymal stem-derived cell, cancer cell and fibroblast spheroids on chitosan-coated surfaces

CD44, a cell-surface glycoprotein, plays an important role in cell proliferation, adhesion, migration, and other biological functions, which are related with the physiological and pathologic activities of cells. Especially, CD44 is extensively expressed within adult bone marrow and has been considered as an important marker for some cancer stem cells (CSCs) in various types of tumors. Therefore, it is essential to understand the variations in CD44 expression of stem cells and cancer cells for further clinical applications. In this paper, CD44 expression was assessed on a human colon cancer cell line (SW620), a human mesenchymal stem-like cell line (3A6), and a human foreskin fibroblast line (Hs68). We used chitosan to establish a suspension culture model to develop multicellular spheroids to mimic a three-dimension (3D) in vivo environment. Obviously, CD44 expression on 3A6 and SW620 cells was dynamic and diverse when they were in the aggregated state suspended on chitosan, while Hs68 cells were relatively stable. Furthermore, we discuss how to regulate CD44 expression of 3A6 and SW620 cells by the interactions between cell and cell, cell and chitosan, as well as cell and microenvironment. Finally, the possible mechanism of chitosan to control CD44 expression of cells is proposed, which may lead to the careful use of chitosan for potential clinical applications.