The Role and Activation Mechanism of TAZ in Hierarchical Microgroove/Nanopore Topography-Mediated Regulation of Stem Cell Differentiation

Abstract

To investigate the role and activation mechanism of TAZ in periodontal ligament stem cells (PDLSCs) perceiving hierarchical microgroove/nanopore topography. Materials and Methods: Titanium surface with hierarchical microgroove/nanopore topography fabricated by selective laser melting combined with alkali heat treatment (SLM-AHT) was used as experimental group, smooth titanium surface (Ti) and sandblasted, largegrit, acid-etched (SLA) titanium surface were employed as control groups. Alkaline phosphatase (ALP) activity assays, qRT-PCR, Western blotting, and immunofluorescence were carried out to evaluate the effect of SLM-AHT surface on PDLSC differentiation. Moreover, TAZ activation was investigated from the perspective of nuclear localization to transcriptional activity. TAZ knockdown PDLSCs were seeded on three titanium surfaces to detect osteogenesis-and adipogenesis-related gene expression levels. Immunofluorescence and Western blotting were employed to investigate the effect of the SLM-AHT surface on actin cytoskeletal polymerization and MAPK signaling pathway. Cytochalasin D and MAPK signaling pathway inhibitors were used to determine whether actin cytoskeletal polymerization and the MAPK signaling pathway were indispensable for TAZ activation. Results: Our results showed that SLM-AHT surface had a greater potential to promote PDLSC osteogenic differentiation while inhibiting adipogenic differentiation than the other two groups. The nuclear localization and transcriptional activity of TAZ were strongly enhanced on the SLM-AHT surface. Moreover, after TAZ knockdown, the enhanced osteogenesis and decreased adipogenesis in SLM-AHT group could not be observed. In addition, SLM-AHT surface could promote actin cytoskeletal polymerization and upregulate pERK and p-p38 protein levels. After treatment with cytochalasin D and MAPK signaling pathway inhibitors, differences in the TAZ subcellular localization and transcriptional activity were no longer observed among the different titanium surfaces. Conclusion: Our results demonstrated that actin cytoskeletal polymerization and MAPK signaling pathway activation triggered by SLM-AHT surface were essential for TAZ activation, which played a dominant role in SLM-AHT surface-induced stem cell fate decision.

Assessing the combined effect of surface topography and substrate rigidity in human bone marrow stem cell cultures

“…Both these observations are in agreement with previous data in the field. Indeed, numerous publications have shown soft substrates to be more adipogenic than stiff substrates [27,80,81] and topographical features to enhance adipogenic potential [26,72,82,83].…”

From the Matrix to the Nucleus and Back: Mechanobiology in the Light of Health, Pathologies, and Regeneration of Oral Periodontal Tissues

“…Molecularly, a clear nuclear accumulation of both YAP and TAZ was registered, which shows both the decisive role of both proteins for osteogenesis and the applicability of such dynamic materials for regenerative purposes [378]. The complex histological composition of the periodontium will, therefore, be an optimal candidate to apply such self-regulating biomaterials, which is especially important regarding tissue-tissue interfaces [148,379].…”

“…This is especially interesting as (i) this mechanism combines principles of transcriptional regulation on the RNA level with protein activity of important mechanotransducers, and (ii) was so far solely described for TAZ but not for YAP [147]. These slight differences might be decisive when it comes to dental implants and regenerative approaches with periodontal stem cells, as TAZ regulation and therefore cellular differentiation is sensitive to the environmental nano topography [148].…”

Poly(ε‐Caprolactone) Substrates with Micro/Nanohierarchical Patterned Structures for Cell Culture

“…[41][42][43] There are cellular and molecular evidences that hierarchical micro/nanotopographies can effectively modulate cellular responses such as cell adhesion, proliferation and differentiation of osteoblasts [44,45] and MSCs [46] compared with single-scale topography. [47][48][49] Scaffold fabrication techniques are very important in dictating the final structural, mechanical properties, and biological response of the implanted biomaterials. [29,31,[50][51][52][53][54] Direct-write fabrication methods are the typical top-down patterning techniques, including focused ion beam, dip pen lithography, and electron beam, which produce polymer patterns under ideal lithography conditions.…”

“…[ 41–43 ] There are cellular and molecular evidences that hierarchical micro/nanotopographies can effectively modulate cellular responses such as cell adhesion, proliferation and differentiation of osteoblasts [ 44,45 ] and MSCs [ 46 ] compared with single‐scale topography. [ 47–49 ]…”