Synthetic poly(2‐acrylamido‐2‐methylpropanesulfonic acid) gel induces chondrogenic differentiation of ATDC5 cells via a novel protein reservoir function

Abstract

We previously demonstrated that a synthetic negatively charged poly(2‐acrylamido‐2‐methylpropanesulfonic acid) (PAMPS) gel induced chondrogenic differentiation of ATDC5 cells. In this study, we clarified the underlying molecular mechanism, in particular, focusing on the events that occurred at the interface between the gel and the cells. Gene expression profiling revealed that the expression of extracellular components was enhanced in the ATDC5 cells that were cultured on the PAMPS gel, suggesting that extracellular proteins secreted from the ATDC5 cells might be adsorbed in the PAMPS gel, thereby contributing to the induction of chondrogenic differentiation. Therefore, we created “Treated‐PAMPS gel,” which adsorbed various proteins secreted from the cultured ATDC5 cells during 7 days. Proteomic analysis identified 27 proteins, including extracellular matrix proteins such as Types I, III, and V collagens and thrombospondin (THBS) in the Treated‐PAMPS gel. The Treated‐PAMPS gel preferentially induced expression of chondrogenic markers, namely, aggrecan and Type II collagen, in the ATDC5 cells compared with the untreated PAMPS gel. Addition of recombinant THBS1 to the ATDC5 cells significantly enhanced the PAMPS‐induced chondrogenic differentiation, whereas knockdown of THBS1 completely abolished this response. In conclusion, we demonstrated that the PAMPS gel has the potential to induce chondrogenic differentiation through novel reservoir functions, and the adsorbed THBS plays a significant role in the induction.

Engineering of an electrically charged hydrogel implanted into a traumatic brain injury model for stepwise neuronal tissue reconstruction

“…Since transplantation of the C1A1 porous hydrogel alone failed to induce angiogenesis, the C1A1 porous hydrogel was immersed in VEGF, which promotes angiogenesis, and implanted into the mice brains. Accumulation of VEGF into hydrogel was expected as we have already reported the reservoir function of hydrogel for growth factors 46 . To confirm the formation of blood vessels in the implanted C1A1 porous hydrogel, in vivo live imaging using a two-photon microscope was performed, and vascularization was observed inside the gel on day 15 (Fig.…”

“…Inflammatory cells such as macrophages/microglia are important for angiogenesis 53 , 54 . Furthermore, hydrogels are used as drug delivery systems 19 ; in fact, we have reported that NaMPS gel has a reservoir function 55 . Thus, the reservoir function of C1A1 porous hydrogels for endogenously secreted growth factors may be involved in angiogenesis, leading to neuronal tissue reconstruction.…”

“…Inflammatory cells such as macrophages/microglia are important for angiogenesis 53,54 . Furthermore, hydrogels are used as drug delivery systems 19 ; in fact, we have reported that NaMPS gel has a reservoir function 55 . 2, right column).…”

Engineering of an electrically charged hydrogel implanted into a traumatic brain injury model for stepwise neuronal tissue reconstruction

“…Inflammatory cells such as macrophages/microglia are important for angiogenesis 50, 51 . Furthermore, hydrogels are used as drug delivery systems 19 ; in fact, we have reported that NaMPS gel has a reservoir function 52 . Thus, the reservoir function of C1A1 porous hydrogels for endogenously secreted growth factors may be involved in angiogenesis, leading to neuronal tissue reconstruction.…”

A Polymer‐Based Chemiresistive Gas Sensor for Selective Detection of Ammonia Gas

“…To this end, poly(2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid) (PAMPSA) organic polymer was selected that has a high affinity to NH 3 . It has been used as hydrogels for drug delivery, [ 28 ] and as scaffolds for cartilage regeneration, [ 29 ] and for NH 3 absorption. [ 30 ] Due to the presence of sulfonate functional group (SO 3 − ) in PAMPSA, its electrical resistance is highly dependent on the pH and the presence of other charged or polar species.…”