High glucose facilitates cell cycle arrest of rat bone marrow multipotent adult progenitor cells through transforming growth factor-β1 and extracellular signal-regulated kinase 1/2 signalling without changing Oct4 expression

Exposure of primary osteoblasts to combined magnetic and electric fields induced spatiotemporal endochondral ossification characteristic gene- and protein expression profiles

Purpose

Molecular processes in primary osteoblasts were analyzed in response to magnetic and electric field exposure to examine its potential impact on bone healing.

Methods

Primary osteoblasts were exposed to a combination of a magnetic field and an additional electric field (EFMF) (20 Hz, 700 mV, 5 mT, continuous sinusoids) in vitro. mRNA- and protein-expressions were assessed during a time interval of 21 days and compared with expression data obtained from control osteoblasts.

Results

We observed an autonomous osteoblast differentiation process in vitro under the chosen cultivation conditions. The initial proliferative phase was characterized by a constitutively high mRNA expression of extracellular matrix proteins. Concurrent EFMF exposure resulted in significanly increased cell proliferation (fold change: 1.25) and reduced mRNA-expressions of matrix components (0.5–0.75). The following reorganization of the extracellular matrix is prerequisite for matrix mineralization and is characterised by increased Ca²⁺ deposition (1.44). On molecular level EFMF exposure led to a significant decreased thrombospondin 1 (THBS1) mRNA- (0.81) and protein- (0.54) expression, which in turn reduced the TGFß1-dependent mRNA- (0.68) and protein- (0.5) expression of transforming growth factor beta induced (ßIG-H3) significantly, an inhibitor of endochondral ossification. Consequently, EFMF exposure stimulated the expression of genes characteristic for endochondral ossification, such as collagen type 10, A1 (1.50), osteopontin (1.50) and acellular communication network factor 3 (NOV) (1.45).

Conclusions

In vitro exposure of osteoblasts to EFMF supports cell differentiation and induces gene- and protein-expression patterns characteristic for endochondral ossification during bone fracture healing in vivo.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40634-022-00477-9.

Multipotent adult progenitor cells induce regulatory T cells and promote their suppressive phenotype via TGFβ and monocyte-dependent mechanisms

Dysregulation of the immune system can initiate chronic inflammatory responses that exacerbate disease pathology. Multipotent adult progenitor cells (MAPC cells), an adult adherent bone-marrow derived stromal cell, have been observed to promote the resolution of uncontrolled inflammatory responses in a variety of clinical conditions including acute ischemic stroke, acute myocardial infarction (AMI), graft vs host disease (GvHD), and acute respiratory distress syndrome (ARDS). One of the proposed mechanisms by which MAPC cells modulate immune responses is via the induction of regulatory T cells (Tregs), however, the mechanism(s) involved remains to be fully elucidated. Herein, we demonstrate that, in an in vitro setting, MAPC cells increase Treg frequencies by promoting Treg proliferation and CD4⁺ T cell differentiation into Tregs. Moreover, MAPC cell-induced Tregs (miTregs) have a more suppressive phenotype characterized by increased expression of CTLA-4, HLA-DR, and PD-L1 and T cell suppression capacity. MAPC cells also promoted Treg activation by inducing CD45RA⁺ CD45RO⁺ transitional Tregs. Additionally, we identify transforming growth factor beta (TGFβ) as an essential factor for Treg induction secreted by MAPC cells. Furthermore, inhibition of indoleamine 2, 3-dioxygenase (IDO) resulted in decreased Treg induction by MAPC cells demonstrating IDO involvement. Our studies also show that CD14⁺ monocytes play a critical role in Treg induction by MAPC cells. Our study describes MAPC cell dependent Treg phenotypic changes and provides evidence of potential mechanisms by which MAPC cells promote Treg differentiation.

The Antimicrobial Peptide Nal-P-113 Exerts a Reparative Effect by Promoting Cell Proliferation, Migration, and Cell Cycle Progression

Objective

The primary purpose of this study was to evaluate the reparative efficacy of a novel antimicrobial peptide, Nal-P-113, in shortening the healing time of oral mucosal ulcers by promoting cell proliferation and migration and accelerating the cell cycle.

Methods

Cell counting kit-8 (CCK-8) and wound-healing assays were used to evaluate the proliferation and migration of human immortalized oral epithelial cells (HIOECs). The cell cycle distribution of HIOECs was analyzed by flow cytometry. Additionally, the RNA levels of EGF, FGF-2, and TGF-β1 of HIOECs were assessed by real-time PCR. Rats were divided into three groups randomly: (a) blank control group; (b) 20 μg/mL Nal-P-113; and (c) 10 ng/mL rhEGF. An oral mucosal ulcer was induced in every rat by the application of 30% acetic acid. An immunohistochemical assay was used to assess the expression of EGF, FGF-2, and TGF-β1 in the rat oral mucosa.

Results

In the CCK-8 assay, the optical density values in the Nal-P-113 and rhEGF groups were found to be significantly higher than that in the blank control group. In addition, the scratch areas in the Nal-P-113 and rhEGF groups were found to be significantly smaller (P<0.05). Cell cycle analysis showed that Nal-P-113 accelerated the entry of HIOECs into the S phase and expedited their cell cycles. The RT-PCR results suggested that Nal-P-113 upregulated the RNA levels of EGF and FGF-2 but downregulated that of TGF-β1 at 24 h and 48 h. Lastly, the immunohistochemical assay verified that Nal-P-113 changed the expression of the above cytokines in rat mucosal ulcers.

Conclusion

Nal-P-113 promoted the repair of oral mucosal ulcers by increasing the EGF and FGF-2 expression and decreasing that of TGF-β1 in HIOECs, accelerating their proliferation and cell cycle progression. The application of Nal-P-113 might serve as an effective therapeutic approach for recurrent aphthous stomatitis.