Effects of thymosin β4 on wound healing of rat palatal mucosa

Osteopontin-derived synthetic peptide SVVYGLR upregulates functional regeneration of oral and maxillofacial soft-tissue injury

Wound healing in the oral and maxillofacial region is a complicated and interactive process. Severe mucosal or skeletal muscle injury by trauma or surgery induces worse healing conditions, including delayed wound closure and repair with excessive scar tissue. These complications lead to persistent functional impairment, such as digestive behavior or suppression of maxillofacial growth in infancy. Osteopontin (OPN), expressed in a variety of cells, is multifunctional and comprises a number of functional domains. Seven amino acids sequence, SVVYGLR (SV peptide), exposed by thrombin cleavage of OPN, has angiogenic activity and promotes fibroblast differentiation into myofibroblasts and increased expression of collagen type III. Additionally, synthetic SV peptide shows faster dermal and oral mucosal wound closure by facilitating cell motility and migratory activities in dermal- or mucosal-derived keratinocytes and fibroblasts. Moreover, cell motility and differentiation in myogenic cell populations are accelerated by SV peptide, which contributes to the facilitation of matured myofibers and scarless healing and favorable functional regeneration after skeletal muscle injury. SV peptide has high affinity with TGF-β, with potential involvement of the TGF-β/Smad signaling pathway. Clinical application of single-dose SV peptide could be a powerful alternative treatment option for excessive oral and maxillofacial wound care to prevent disadvantageous events.

Synthetic peptide SVVYGLR upregulates cell motility and facilitates oral mucosal wound healing

Osteopontin-derived SVVYGLR (SV) 7-amino-acid sequence is a multifunctional and synthetic SV peptide implicated in angiogenesis, production of collagen III, and fibroblast differentiation into myofibroblasts. This study investigated the effect of the SV peptide on mucosal wound healing activity. Normal human-derived gingival fibroblasts (NHGF) and human oral mucosa keratinocytes (HOMK) were used for in vitro experiments. In addition, an oral punch wound was prepared at the buccal mucosa in male rats aged 11 weeks, and we evaluated the effect of local injection of SV peptide on wound healing. The synthetic SV peptide showed no influence on the proliferation and adhesion properties of NHGF and HOMK, but it enhanced the cell motility and migration activities. TGF-β1 receptor inhibitor, SB431542 or SB505124, substantially suppressed the SV peptide-induced migration activity, suggesting an involvement of TGF-β1 receptor activation. Furthermore, SV peptide accelerated the healing process of an in vivo oral wound model, compared with control groups. Further immunohistological staining of wound tissue revealed that an increase in capillary growth and the greater number of fibroblasts and myofibroblasts that migrated into the wound area might contribute to the facilitation of the healing process produced by the SV peptide. The SV peptide has beneficial effects on oral wound healing through enhancement of the earlier phase consisting of angiogenesis and remodeling with granulation tissue. The synthetic SV peptide can be a useful treatment option, particularly for intractable mucosal wounds caused by trauma or surgery for progressive lesions such as oral cancer.

Purinergic Signaling Involvement in Thymosin β4-mediated Corneal Epithelial Cell Migration

Purpose: This study aimed to determine the effect of thymosin beta 4 (Tβ4) on human corneal epithelial cell migration and the downstream signaling pathways. Tβ4 has a role in tissue development, cell migration, inflammation, and wound healing. A previous study showed that Tβ4 directly binds to F0-F1 ATP synthase. Other studies reported the role of extracellular ATP and purinergic receptors in cell migration with several cell types. Despite advancing to the clinical stage for treatment of eye disorders, the effect of Tβ4 on human corneal epithelial cell (HCEC) migration and proliferation and the precise downstream signaling pathway(s) have not been identified. Methods: Various concentrations of Tβ4 were tested in vitro on human corneal epithelial cell proliferation using the CCK-8 Kit and on cell migration using the gap closure migration assay. Additionally, ATP levels at various time points were determined using the ATP Lite One-Step Kit. The Fluo 8 NO Wash Calcium Assay Kit was used to measure the intracellular Ca²⁺ concentration after treatment with various concentrations of Tβ4. P2X7 inhibitors were tested on ATP signaling and migration. Total- and phospho-ERK1/2 levels were determined in western blot. Results: Tβ4 enhanced HCEC proliferation and migration in a dose- and time-dependent manner. Moreover, these functions were related to increased extracellular ATP levels, intracellular Ca²⁺ influx, and ERK1/2 phosphorylation. Tβ4-mediated HCEC migration was inhibited by specific P2X7 purinergic receptor antagonists suggesting the role of this receptor in Tβ4-mediated human corneal epithelial cell migration. Conclusions: These results suggest that Tβ4-mediated HCEC proliferation and migration are associated with increased ATP levels, P2X7 R-mediated Ca²⁺ influx, and the ERK1/2 signaling pathway. This study begins to describe the mechanisms for Tβ4-mediated corneal healing and regeneration.

Thymosin β4-Enhancing Therapeutic Efficacy of Human Adipose-Derived Stem Cells in Mouse Ischemic Hindlimb Model

Thymosin β4 (Tβ4) is a G-actin sequestering protein that contributes to diverse cellular activities, such as migration and angiogenesis. In this study, the beneficial effects of combined cell therapy with Tβ4 and human adipose-derived stem cells (hASCs) in a mouse ischemic hindlimb model were investigated. We observed that exogenous treatment with Tβ4 enhanced endogenous TMSB4X mRNA expression and promoted morphological changes (increased cell length) in hASCs. Interestingly, Tβ4 induced the active state of hASCs by up-regulating intracellular signaling pathways including the PI3K/AKT/mTOR and MAPK/ERK pathways. Treatment with Tβ4 significantly increased cell migration and sprouting from microbeads. Moreover, additional treatment with Tβ4 promoted the endothelial differentiation potential of hASCs by up-regulating various angiogenic genes. To evaluate the in vivo effects of the Tβ4-hASCs combination on vessel recruitment, dorsal window chambers were transplanted, and the co-treated mice were found to have a significantly increased number of microvessel branches. Transplantation of hASCs in combination with Tβ4 was found to improve blood flow and attenuate limb or foot loss post-ischemia compared to transplantation with hASCs alone. Taken together, the therapeutic application of hASCs combined with Tβ4 could be effective in enhancing endothelial differentiation and vascularization for treating hindlimb ischemia.

Humic Acid Enhances Wound Healing in the Rat Palate

Introduction

Humic acid was previously shown to enhance cutaneous wound healing and show antibacterial properties; however, it has not been used for wound healing in the oral cavity. Thus, the goal of this study was the evaluation of the effect of the humic acid on the healing of excisional wounds in an experimental rat study.

Materials and Methods

A circular wound on mid-palatal surfaces was made on a total of 77 Wistar rats by using a 3-mm biopsy punch under anesthesia. The animals were divided into 4 groups as baseline, saline control (0.09%), chlorhexidine gluconate (0.05%), and humic acid (80 mg/kg) and were treated with these materials for 7 days.

Results

The rats were observed for 3 weeks in order to track the wound closure rates. Both humic acid treatment and chlorhexidine gluconate treatment resulted in statistically significant enhanced rate of wound closure compared to the saline control on both the 1st and 2nd weeks of treatment. Humic acid treatment for the wounds in the palate resulted in enhanced recovery compared to not only saline control but also chlorhexidine gluconate treatment.

Conclusion

In this study, humic acid was shown to enhance healing of oral wounds for the first time in the literature. These findings indicate that humic acid can be used as an alternative to current treatment methods for oral wounds.

Landscape limits gene flow and drives population structure in Agassiz's desert tortoise (Gopherus agassizii)

Distance, environmental heterogeneity and local adaptation can strongly influence population structure and connectivity. Understanding how these factors shape the genomic landscape of threatened species is a major goal in conservation genomics and wildlife management. Herein, we use thousands (6,859) of single nucleotide polymorphism markers and spatial data from hundreds of individuals (n = 646) to re-evaluate the population structure of Agassiz's desert tortoise (Gopherus agassizii). Analyses resolve from 4 to 8 spatially well-defined clusters across the range. Western, central, and southern populations within the Western Mojave recovery unit are consistent throughout, while analyses sometimes merge other recovery units depending on the level of clustering. Causal modeling consistently associates genetic connectivity with least-cost distance, based on multiple landscape features associated with tortoise habitat, better than geographic distance. Some features include elevation, soil depth, rock volume, precipitation, and vegetation coverage, suggesting that physical, climatic, and biotic landscape features have played a strong evolutionary role restricting gene flow between populations. Further, 12 highly differentiated outlier loci have associated functions that may be involved with neurogenesis, wound healing, lipid metabolism, and possibly vitellogenesis. Together, these findings have important implications for recovery programs, such as translocations, population augmentation, reproduction in captivity and the identification of ecologically important genes, opening new venues for conservation genomics in desert tortoises.

Effects of phosphatidylserine-containing liposomes on odontogenic differentiation of human dental pulp cells

Phosphatidylserine (PS) is known to enhance biomineralization due to the ability to accumulate calcium ions. In this study, the effects of PS on odontogenic differentiation and mineralization of human dental pulp cells (HDPCs) were investigated using phosphatidylserine-containing liposomes (PSLs). PSL was slightly cytotoxic at 125 µM in growth medium, and ALP activity was up-regulated in the PSL-treated HDPCs at non-cytotoxic concentrations. Mineralization was also enhanced by PSL, while mRNA expressions of DSPP and OCN genes were slightly attenuated. The mRNA expression of Runx2 was not altered by PSL. It is thus likely that PSL selectively affected odontogenic differentiation processes of HDPC. Finally, the interaction between PSL and HDPC was investigated by staining with annexin V-FITC in PSL-treated HDPC. It was found that PS was gradually incorporated into HDPC cytoplasm for several days. The results of this study suggest that PSL is able to stimulate dentin formation in dental pulps.

Thymosin β4 and β10 in Sjögren's syndrome: saliva proteomics and minor salivary glands expression

Background

In the present study, we investigated whether thymosin β (Tβ) in saliva and in minor salivary glands is differentially expressed in patients with primary Sjögren’s syndrome (pSS) and patients with autoimmune diseases (systemic sclerosis [SSc], systemic lupus erythematosus [SLE], and rheumatoid arthritis [RA], with and without sicca syndrome [ss]).

Methods

Saliva specimens of nine patients with pSS, seven with ss/SSc, seven with ss/SLE, seven with ss/RA, seven with SSc, seven with SLE, and seven with RA, as well as ten healthy subjects, were analyzed using a high-performance liquid chromatograph coupled with a mass spectrometer equipped with an electrospray ionization source to investigate the presence and levels of Tβ₄, Tβ₄ sulfoxide, and Tβ₁₀. Immunostaining for Tβ₄ and Tβ₁₀ was performed on minor salivary glands of patients with pSS and ss.

Results

Tβ₄ levels were statistically higher in patients with pSS with respect to the other subgroups. Tβ₁₀ was detectable in 66.7 % of patients with pSS and in 42.8 % of those with ss/SSc, while Tβ₄ sulfoxide was detectable in 44.4 % of patients with pSS and in 42.9 % of those with ss/SSc. Tβ₁₀ and Tβ₄ sulfoxide were not detectable in patients without associated ss and in healthy control subjects. Regarding thymosin immunostaining, all patients had immunoreactivity for Tβ₁₀, and a comparable distribution pattern in the four different subgroups of patients was observed. Tβ₄ immunoreactivity was present in patients with ss/SSc and those with ss/SLE, while it was completely absent in patients with pSS and those with ss/RA.

Conclusions

Our data show that higher salivary Tβ expression characterizes patients with pSS, while Tβ₄ sulfoxide and Tβ₁₀ salivary expression was selectively present in patients with sicca symptoms. Moreover, at the immunohistochemical level in patients with pSS, minor salivary glands showed a peculiar pattern characterized by immunostaining for Tβ₁₀ in acinar cells in the absence of any reactivity for Tβ₄. These findings, taken together, suggest a different role for Tβ₄ and Tβ₁₀ in patients with pSS who have ss and other autoimmune disease.

Thymosin Beta-4 Recombinant Adeno-associated Virus Enhances Human Nucleus Pulposus Cell Proliferation and Reduces Cell Apoptosis and Senescence

Background:

Thymosin beta-4 (TB-4) is considered key roles in tissue development, maintenance and pathological processes. The study aimed to prove TB-4 positive biological function on nucleus pulposus (NP) cell apoptosis and slowing the process of cell aging while increasing the cell proliferation.

Methods:

TB-4 recombinant adeno-associated virus (AAV) was constructed and induced to human NP cells. Cell of same group were cultured without gene modification as controlled group. Proliferation capacity and cell apoptosis were observed during 6 passages of the cells. Morphology and expression of the TB-4 gene were documented as parameter of cell activity during cell passage.

Results:

NP cells with TB-4 transfection has normal TB-4 expression and exocytosis. NP cells with TB-4 transfection performed significantly higher cell activity than that at the control group in each generation. TB-4 recombinant AAV-transfected human NP cells also show slower cell aging, lower cell apoptosis and higher cell proliferation than control group.

Conclusions:

TB-4 can prevent NP cell apoptosis, slow NP cell aging and promote NP cell proliferation. AAV transfection technique was able to highly and stably express TB-4 in human NP cells, which may provide a new pathway for innovation in the treatment of intervertebral disc degenerative diseases.

Thymosin Beta-4 Suppresses Osteoclastic Differentiation and Inflammatory Responses in Human Periodontal Ligament Cells

Background

Recent reports suggest that thymosin beta-4 (Tβ4) is a key regulator for wound healing and anti-inflammation. However, the role of Tβ4 in osteoclast differentiation remains unclear.

Purpose

The purpose of this study was to evaluate Tβ4 expression in H₂O₂-stimulated human periodontal ligament cells (PDLCs), the effects of Tβ4 activation on inflammatory response in PDLCs and osteoclastic differentiation in mouse bone marrow-derived macrophages (BMMs), and identify the underlying mechanism.

Methods

Reverse transcription-polymerase chain reactions and Western blot analyses were used to measure mRNA and protein levels, respectively. Osteoclastic differentiation was assessed in mouse bone marrow-derived macrophages (BMMs) using conditioned medium (CM) from H₂O₂-treated PDLCs.

Results

Tβ4 was down-regulated in H₂O₂-exposed PDLCs in dose- and time-dependent manners. Tβ4 activation with a Tβ4 peptide attenuated the H₂O₂-induced production of NO and PGE₂ and up-regulated iNOS, COX-2, and osteoclastogenic cytokines (TNF-α, IL-1β, IL-6, IL-8, and IL-17) as well as reversed the effect on RANKL and OPG in PDLCs. Tβ4 peptide inhibited the effects of H₂O₂ on the activation of ERK and JNK MAPK, and NF-κB in PDLCs. Furthermore, Tβ4 peptide inhibited osteoclast differentiation, osteoclast-specific gene expression, and p38, ERK, and JNK phosphorylation and NF-κB activation in RANKL-stimulated BMMs. In addition, H₂O₂ up-regulated Wnt5a and its cell surface receptors, Frizzled and Ror2 in PDLCs. Wnt5a inhibition by Wnt5a siRNA enhanced the effects of Tβ4 on H₂O₂-mediated induction of pro-inflammatory cytokines and osteoclastogenic cytokines as well as helping osteoclastic differentiation whereas Wnt5a activation by Wnt5a peptide reversed it.

Conclusion

In conclusion, this study demonstrated, for the first time, that Tβ4 was down-regulated in ROS-stimulated PDLCs as well as Tβ4 activation exhibited anti-inflammatory effects and anti-osteoclastogenesis in vitro. Thus, Tβ4 activation might be a therapeutic target for inflammatory osteolytic disease, such as periodontitis.

Pharmacological activation of estrogen receptors-α and -β differentially modulates keratinocyte differentiation with functional impact on wound healing

Estrogen deprivation is considered responsible for many age-related processes, including poor wound healing. Guided by previous observations that estradiol accelerates re‑epithelialization through estrogen receptor (ER)‑β, in the present study, we examined whether selective ER agonists [4,4',4''-(4-propyl [1H] pyrazole-1,3,5-triyl)‑trisphenol (PPT), ER‑α agonist; 2,3-bis(4-hydroxyphenyl)-propionitrile (DPN), ER‑β agonist] affect the expression of basic proliferation and differentiation markers (Ki‑67, keratin‑10, ‑14 and ‑19, galectin‑1 and Sox‑2) of keratinocytes using HaCaT cells. In parallel, ovariectomized rats were treated daily with an ER modulator, and wound tissue was removed 21 days after wounding and routinely processed for basic histological analysis. Our results revealed that the HaCaT keratinocytes expressed both ER‑α and ‑β, and thus are well-suited for studying the effects of ER agonists on epidermal regeneration. The activation of ER‑α produced a protein expression pattern similar to that observed in the control culture, with a moderate expression of Ki‑67 being observed. However, the activation of ER‑β led to an increase in cell proliferation and keratin‑19 expression, as well as a decrease in galectin‑1 expression. Fittingly, in rat wounds treated with the ER‑β agonist (DPN), epidermal regeneration was accelerated. In the present study, we provide information on the mechanisms through which estrogens affect the expression patterns of selected markers, thus modulating keratinocyte proliferation and differentiation; in addition, we demonstrate that the pharmacological activation of ER-α and -β has a direct impact on wound healing.

Effects of dimethyloxalylglycine on wound healing of palatal mucosa in a rat model

Background

Rapid wound healing of oral soft tissue may reduce the opportunity of infection and discomfort of patients. Previous studies have demonstrated that enhancement of angiogenesis is an effective way to accelerate wound repair. In this study, to enhance angiogenesis and healing of palatal wounds, dimethyloxalylglycine (DMOG) was applied to a rat palatal wound model. DMOG is known to inhibit oxygen-dependent degradation of hypoxia inducible factor-1 alpha (HIF-1α), which can lead to up-regulation of angiogenesis markers, favoring wound repair. We also evaluated the effects of DMOG on cell migration and HIF-1α expression of rat palatal (RP) cells. Furthermore, mRNA and protein expression of vascular endothelial growth factor (VEGF) were analyzed in DMOG-treated RP cells.

Methods

Primary cultures of rat palatal (RP) cells were obtained from Sprague–Dawley (SD) rats. Effects of DMOG on cell viability and migration of RP cells were evaluated by using a formazan and culture insert, respectively. VEGF mRNA was observed by real-time PCR, and VEGF and HIF-1α proteins were detected by Western blotting. For the animal study, excisional wounds, 3 mm in diameter, were made at the central part of the palate of SD rats. DMOG with hyaluronic acid ointment was topically applied three times during 1 week, and then wound closures were quantitated photographically and histologically.

Results

DMOG was cytotoxic to RP cells at concentrations higher than 2 mM and did not affect cell migration at non-cytotoxic concentrations. mRNA and protein expression of VEGF were significantly stimulated by DMOG treatment. The protein level of HIF-1α was also stabilized in RP cells by DMOG. In the animal study, groups treated with 1 mg/ml DMOG showed an increase of rat palatal wound contractures.

Conclusions

DMOG enhanced wound healing of rat palatal mucosa, which was likely due to the angiogenic effect of the agent.