6563wileyonlinelibrary.com in order to maintain multipotency. When using MSCs for regenerative medicine, it is important to obtain a suffi cient number of cells that maintain pluripotency without compromising MSC senescence. [ 3,4 ] Material systems that mimic the natural niche environment of MSCs may offer an alternative to the use of complex cocktails of soluble factors used in the culture media. Previous studies show that the cell/material interface plays an essential role on MSC function and differentiation, encompassing promising approaches to manipulate differentiation of stem cells ranging from chemistry, [5][6][7] surface modifi cations, [ 8,9 ] topography, [10][11][12] stiffness, [ 13,14 ] and even dynamic material properties such as stress relaxation. [ 15 ] While we are starting to identify the range of materials properties that can be used to drive stem cell differentiation, there is much left to discover and understand. In addition, cells do not feel the surface of materials directly, but through an intermediate layer of adsorbed proteins. The conformation and distribution of this protein layer will determine integrin binding and the organization of focal adhesions, which in turn will infl uence cell signaling and hence fate. [16][17][18][19][20] Acrylates are common biomaterials with tunable physical properties. [ 21 ] In this work we used substrates that slightly differ in surface chemistry, varying only one methyl group in the side chain-poly(ethyl acrylate) (PEA) and poly(methyl acrylate) (PMA). Using this material system, we have previously demonstrated that this subtle variation in surface chemistry modulates the conformation of adsorbed fi bronectin (FN). Typically, FN adsorbs to synthetic materials in a globular morphology, as it does on PMA. However, on PEA, the FN molecules spontaneously organize into nanonetworks, a process that we have termed material-driven fi bronectin fi brillogenesis. [22][23][24] We hypothesize that these FN nanonetworks assembled on PEA infl uence the behavior of MSCs. In this new report, we have investigated the role of FN nanonetworks on MSC adhesion, differentiation (osteogenic, adipogenic), and growth, by culturing cells in absence of differentiation factors. ResultsWe have used C3H10T1/2 cells, an established murine multipotent mesenchymal stem (mMSC) cell line from 14-to 17-d-old

Myogenic regeneration occurs through a chain of events beginning with the output of satellite cells from quiescent state, formation of competent myoblasts and later fusion and differentiation into myofibres. Traditionally, growth factors are used to stimulate muscle regeneration but this involves serious off-target effects, including alterations in cell homeostasis and cancer. In this work, we have studied the use of zinc to trigger myogenic differentiation. We show that zinc promotes myoblast proliferation, differentiation and maturation of myofibres. We demonstrate that this process occurs through the PI3K/Akt pathway, via zinc stimulation of transporter Zip7. Depletion of zinc transporter Zip7 by RNA interference shows reduction of both PI3K/Akt signalling and a significant reduction of multinucleated myofibres and myotubes development. Moreover, we show that mature myofibres, obtained through stimulation with high concentrations of zinc, accumulate zinc and so we hypothesise their function as zinc reservoirs into the cell.

Deregulated de novo lipid synthesis (DNLS) is a potential druggable vulnerability in glioblastoma (GBM), a highly lethal and incurable cancer. Yet the molecular mechanisms that determine susceptibility to DNLS-targeted therapies remain unknown, and the lack of brain-penetrant inhibitors of DNLS has prevented their clinical evaluation as GBM therapeutics. Here, we report that YTX-7739, a clinical-stage inhibitor of stearoyl CoA desaturase (SCD), triggers lipotoxicity in patient-derived GBM stem-like cells (GSCs) and inhibits fatty acid desaturation in GSCs orthotopically implanted in mice. When administered as a single agent, or in combination with temozolomide (TMZ), YTX-7739 showed therapeutic efficacy in orthotopic GSC mouse models owing to its lipotoxicity and ability to impair DNA damage repair. Leveraging genetic, pharmacological, and physiological manipulation of key signaling nodes in gliomagenesis complemented with shotgun lipidomics, we show that aberrant MEK/ERK signaling and its repression of the energy sensor AMP-activated protein kinase (AMPK) primarily drive therapeutic vulnerability to SCD and other DNLS inhibitors. Conversely, AMPK activation mitigates lipotoxicity and renders GSCs resistant to the loss of DNLS, both in culture and in vivo, by decreasing the saturation state of phospholipids and diverting toxic lipids into lipid droplets. Together, our findings reveal mechanisms of metabolic plasticity in GSCs and provide a framework for the rational integration of DNLS-targeted GBM therapies.

Fibronectin fibrillogenesis is the physiological process by which cells elaborate a fibrous FN matrix. Poly(ethyl acrylate), PEA, has been described to induce a similar process upon simple adsorption of fibronectin (FN) from a protein solution -in the absence of cells -leading to the so-called material-driven fibronectin fibrillogenesis. Poly(methyl acrylate), PMA, is a polymer with very similar chemistry to PEA, on which FN is adsorbed keeping the globular conformation of the protein in solution. We have used radical polymerisation to synthesise copolymers with controlled EA/MA ratio seeking to modulate the degree of FN fibrillogenesis. The physico-chemical properties of the system were studied using dynamicmechanical analysis, differential scanning calorimetry and water contact angle. Both the degree of FN fibrillogenesis and the availability of the integrin binding region of FN directly depend on the percentage of EA in the copolymer, whereas the same total amount of FN was adsorbed regardless the EA/MA ratio. Cell morphology adhesion and differentiation of murine C2C12 were shown to depend on the degree of FN fibrillogenesis previously attained on the material surface. Myogenic differentiation was enhanced on the copolymers with higher EA content, i.e. more interconnected FN fibrils.

Hyaluronan-based hydrogels are among the most promising neural tissue engineering materials because of their biocompatibility and the immunomodulation capabilities of their degradation byproducts. Despite these features, the problems related to their handling and mechanical properties have not yet been solved. In the present work it is proposed to address these drawbacks through the development of nanohybrid materials in which different nanometric phases (carbon nanotubes, mesoporous silica nanoparticles) are embedded in a crosslinked hyaluronan matrix. These nanohybrid matrices were next processed in the shape of cylindrical conduits aimed at promoting and improving neural stem cell differentiation and regeneration in neural tracts. These constructs could be of use specifically for peripheral nerve regeneration.Results of the study show that the inclusion of the different phases improved physico-chemical features of the gel such as its relative electrical permittivity, water intake and elastic modulus, giving hints on how the nanometric phase interacts with hyaluronan in the composite as well as for their potential in combined therapeutic approaches. Regarding the in vitro biological 2 behavior of the hybrid tubular scaffolds, an improved early cell adhesion and survival of Schwann cells in their lumen was found, as compared to conduits made of pure hyaluronan gels. Furthermore, the differentiation and survival of neural precursors was not compromised, despite alleged safety concerns.