Cyclosporin-induced downregulation of the expression of E-cadherin during proliferation of edentulous gingival epithelium in rats

Mitochondrial Dysfunction in Periodontitis and Associated Systemic Diseases: Implications for Pathomechanisms and Therapeutic Strategies

Periodontitis is a chronic infectious disorder damaging periodontal tissues, including the gingiva, periodontal ligament, cementum, and alveolar bone. It arises from the complex interplay between pathogenic oral bacteria and host immune response. Contrary to the previous view of "energy factories", mitochondria have recently been recognized as semi-autonomous organelles that fine-tune cell survival, death, metabolism, and other functions. Under physiological conditions, periodontal tissue cells participate in dynamic processes, including differentiation, mineralization, and regeneration. These fundamental activities depend on properly functioning mitochondria, which play a crucial role through bioenergetics, dynamics, mitophagy, and quality control. However, during the initiation and progression of periodontitis, mitochondrial quality control is compromised due to a range of challenges, such as bacterial-host interactions, inflammation, and oxidative stress. Currently, mounting evidence suggests that mitochondria dysfunction serves as a common pathological mechanism linking periodontitis with systemic conditions like type II diabetes, obesity, and cardiovascular diseases. Therefore, targeting mitochondria to intervene in periodontitis and multiple associated systemic diseases holds great therapeutic potential. This review provides advanced insights into the interplay between mitochondria, periodontitis, and associated systemic diseases. Moreover, we emphasize the significance of diverse therapeutic modulators and signaling pathways that regulate mitochondrial function in periodontal and systemic cells.

Geraniol protects against cyclosporine A-induced renal injury in rats: Role of Wnt/β-catenin and PPARγ signaling pathways

AIMS

The nephrotoxicity of cyclosporine A (CsA) limits its use as an immunosuppressant. Wnt/β-catenin signaling is involved in the pathogenesis of both acute and chronic kidney disease, and it is inhibited by peroxisome proliferator-activated receptor gamma (PPARγ). We aimed to evaluate if geraniol, which can modulate both PPARγ and Wnt signaling, could protect against CsA-induced nephrotoxicity.

MATERIALS AND METHODS

Rats (6 groups) received the vehicle or a combination of CsA (30 mg/kg) with the vehicle, geraniol (50, 100, or 200 mg/kg), or the PPARγ agonist pioglitazone for 4 weeks. Blood pressure (BP), markers of renal injury (serum urea, serum creatinine, blood urea nitrogen, and urinary NAG), oxidative stress (glutathione peroxidase), inflammation (ICAM-1, IL-18, and NF-κB), apoptosis (caspase-3), extracellular matrix remodeling [matrix metalloproteinase-9 (MMP-9)], and fibrosis (TGF-β1, Smad3, and Smad7) were assessed. Renal histological analysis, Wnt signaling components (Wnt-4/β-catenin and E-cadherin), and PPARγ expression were evaluated.

KEY FINDINGS

CsA group had renal injury, as well as increased BP, renal oxidative stress, inflammation, and fibrosis. The latter changes were associated with altered renal architecture, active Wnt signaling (higher Wnt-4 and β-catenin expression and E-cadherin down-regulation), and lower PPARγ levels. Geraniol protected against kidney damage and the associated biochemical and histomorphological changes in a dose-dependent manner. The latter effects were comparable or superior to those of pioglitazone.

SIGNIFICANCE

The down-regulation of Wnt/β-catenin and the increase in PPARγ by geraniol suggest that both pathways are involved in its renoprotective potential. The study highlights geraniol as a valuable protective asset against chemically induced nephrotoxicity.

Antioxidants protect against gingival overgrowth induced by cyclosporine A

OBJECTIVE

We investigated the importance of reactive oxygen species (ROS) on developing gingival overgrowth (GO) and then introduced the antioxidant strategy to prevent, or even reduce GO.

BACKGROUND

Gingival overgrowth is a common side effect of the patients receiving cyclosporine A (CsA), an immune suppressant. Although it has been broadly investigated, the exact pathogenesis of the induced GO is still uncertain.

METHODS

We cultured human primary gingival fibroblasts and used animal model of GO to investigate the ameliorative effects of antioxidants on CsA-induced GO. To examine the CsA-induced oxidative stress, associated genes and protein expression, and the overgrown gingiva of rats by using immunocytochemistry, confocal laser scanning microscopy, real-time PCR, ELISA, gelatin zymography, gingival morphological, and immunohistochemical analysis.

RESULTS

We found for the first time that ROS was responsible for the CsA-induced oxidative stress and TGF-β1 expression in human primary gingival fibroblasts, as well as the GO of rats. The antioxidants (oxidative scavenger of vitamin E and an antioxidative enzyme inducer of hemin) ameliorated CsA-induced pathological and morphological alterations of GO without affected the CsA-suppressed il-2 expression in rats. CsA-induced oxidative stress, HO-1, TGF-β1, and type II EMT were also rescued by antioxidants treatment.

CONCLUSIONS

We concluded that CsA repetitively stimulating the production of ROS is the cause of CsA-GO which is ameliorated by treating antioxidants, including vitamin E and sulforaphane. Furthermore, the immunosuppressive effect of CsA is not interfered by antioxidant treatments in rats. This finding may thus help the clinician devise better prevention strategies in patients susceptible to GO.

Drug-Induced Gingival Overgrowth: The Effect of Cyclosporin A and Mycophenolate Mophetil on Human Gingival Fibroblasts. Biomedicines. 2020;8. [PMID: 32708980 PMCID: PMC7400382 DOI: 10.3390/biomedicines8070221]

Drug-induced gingival overgrowth may occur after a chronic administration of three classes of systemic drugs: Anticonvulsants, immunosuppressants, and calcium channel blockers. This study aimed to investigate how cyclosporin A and mycophenolate mophetil (immunosuppressive drugs) could interfere with human gingival fibroblasts functions, leading to gingival enlargement. Human gingival fibroblasts derived from the tissue of a 60-year-old female were cultured in a DMEME medium. A stock solution with 1 mg/mL of mycophenolate and 1 mg/mL of cyclosporine were prepared and dissolved in a DMEM medium to prepare a serial dilution at the concentrations of 5000, 2000, 1000, 500, and 100 ng/mL, for both treatments. Cell viability was measured using the PrestoBlue™ Reagent Protocol. Quantitative real-time RT-PCR was performed in order to analyze the expression of 57 genes coding for gingival fibroblasts "Extracellular Matrix and Adhesion Molecules". Mycophenolate and cyclosporine had no effect on fibroblast cell viability at 1000 ng/mL. Both the treatments showed similar effects on the expression profiling of treated cells: Downregulation of most extracellular matrix metalloproteases genes (MMP8, MMP11, MMP15, MMP16, MMP24) was assessed, while CDH1, ITGA2, ITGA7, LAMB3, MMP12, and MMP13 were recorded to be upregulated in fibroblasts treated with immunosuppressive drugs. It has been demonstrated that gingival overgrowth can be caused by the chronic administration of cyclosporin A and mycophenolate mophetil. However, given the contrasting data of literature, further investigations are needed, making clear the possible effects of immunosuppressive drugs on fibroblasts.

SPOCK1 is a novel inducer of epithelial to mesenchymal transition in drug-induced gingival overgrowth

Few studies have investigated the role of extracellular-matrix proteoglycans in the pathogenesis of drug-induced gingival overgrowth (DIGO). SPOCK1 is an extracellular proteoglycan that induces epithelial to mesenchymal transition (EMT) in several cancer cell lines and exhibits protease-inhibitory activity. However, the role of SPOCK1 in non-cancerous diseases such as DIGO has not been well-addressed. We demonstrated that the expression of SPOCK1, TGF-β1, and MMP-9 in calcium channel blocker-induced gingival overgrowth is higher than that in non-overgrowth tissues. Transgenic mice overexpressing Spock1 developed obvious gingival-overgrowth and fibrosis phenotypes, and positively correlated with EMT-like changes. Furthermore, in vitro data indicated a tri-directional interaction between SPOCK1, TGF-β1, and MMP-9 that led to gingival overgrowth. Our study shows that SPOCK1 up-regulation in a noncancerous disease and SPOCK1-induced EMT in gingival overgrowth occurs via cooperation and crosstalk between several potential signaling pathways. Therefore, SPOCK1 is a novel therapeutic target for gingival overgrowth and its expression is a potential risk of EMT induction in cancerous lesions.

Fibroblast-enhanced cyclophilin A releasing from U937 cell upregulates MMP-2 in gingival fibroblast

OBJECTIVE

This in vitro study aimed to evaluate the expression of cyclophilin A (CyPA) in U937 monocytic cells after coculturing with the human gingival fibroblasts (HGFs) and the effect of CyPA on the augmentation of MMP-2 expression in the coculture environment.

BACKGROUND

Leukocyte infiltration in gingival connective tissue is one of the major findings in the lesions of inflammatory periodontal diseases. A crosstalk between the resident gingival fibroblasts and the recruited inflammatory cells that promote the expression of matrix metalloproteinases (MMPs) was proposed based on recent findings, whereas the cluster of differentiation 147 (CD147)-CyPA pathway was suggested to be involved with the crosstalk.

MATERIAL AND METHODS

CyPA was released into media, in the independent or transwell coculture of HGF and U937 cells, as determined by enzyme-linked immunosorbent assay, whereas intracellular mRNA expressions for CyPA and MMP-2 were examined by quantitative real-time polymerase chain reaction, in the transwell coculture or conditional medium models. Zymography was conducted to analyze the activities of pro-MMP-2/MMP-2 released into the media.

RESULTS

(a) A significantly increased CyPA protein level was observed in the transwell coculture media compared with that in the independent culture. (b) The transwell coculture-enhanced mRNA expression for CyPA was noticed in U937 cells but not in HGFs. After adding with HGF-conditioned medium, the mRNA enhancement in U937 cells occurred in a dose-dependent manner. (c) Although the MMP-2 activities significantly increased after transwell coculturing, the MMP-2 mRNA enhancement was observed only in HGFs. (d) Exogenous CyPA could enhance MMP-2 activities in HGFs in a dose-dependent manner. However, the CyPA antagonist reduced the MMP-2 activities in the transwell cocultures. (e) Moreover, the CyPA-enhanced MMP-2 activity in HGF was decreased significantly by the pathway inhibitor for c-Jun amino-terminal kinase (JNK).

CONCLUSION

Based on the present findings, we suggest that gingival fibroblasts could enhance the CyPA release from U937 cells, via the JNK pathway, resulting in MMP-2 enhancement in fibroblasts. The finding shed light on a new mechanism of cellular interaction involving MMP-2 and CyPA, in two cells.

CD147 self-regulates matrix metalloproteinase-2 release in gingival fibroblasts after coculturing with U937 monocytic cells

BACKGROUND

Cluster of differentiation 147 (CD147) is a multifunctional glycoprotein that functions as an inducer of matrix metalloproteinase (MMP) expression in fibroblasts. Synergistically enhanced MMP-2 expression was recently observed in the coculture of human gingival fibroblasts (HGFs) and U937 human monocytic cells; however, the responsible mechanisms have not yet been fully established. The aim of this study was to evaluate the release of soluble CD147 in HGFs after coculturing with U937 cells and its functional effect on the enhancement of MMP-2 expression in HGFs.

METHODS

Enzyme-linked immunosorbent assay was used to determine the amount of CD147 protein in media, whereas real-time polymerase chain reaction was performed to evaluate the mRNA levels of CD147 and MMP-2 in HGFs and U937 cells. The enzyme activities of MMP-2 released from cells were examined by zymography. Transwell coculturing and conditioned media treatments were selected to rule out the effect of direct contact of HGFs and U937 cells.

RESULTS

The protein and mRNA expression of CD147 in HGFs were enhanced after transwell coculturing with U937 cells and exposure to U937-conditioned medium. MMP-2 enzyme activities in HGFs were also significantly increased by the coculturing methods. Administration of exogenous CD147 enhanced MMP-2 expression in HGFs, whereas treatment with cyclosporine-A, which inhibited CD147 expression, reduced U937-enhanced MMP-2 expression in HGFs.

CONCLUSIONS

CD147 can interact with fibroblasts to stimulate the expression of MMPs associated with periodontal extracellular matrix degradation. This study has demonstrated that CD147 released from fibroblasts might play a role in monocyte-enhanced MMP-2 expression in HGFs.

Epithelial to mesenchymal transition in Cyclosporine A-induced rat gingival overgrowth

BACKGROUND AND OBJECTIVE

Epithelial-mesenchymal transition (EMT) has been proved to occur in drug-induced gingival overgrowth. However, the specific pathogenic mechanism remains uncertain. The aim of this study is to examine the expression of EMT markers in cyclosporine A (CsA)-induced gingival overgrowth in rat models.

MATERIAL AND METHODS

Thirty-six rats were randomly divided into two groups. The experimental group received CsA therapy subcutaneously in a daily dose of 10mg/kg, and the other group was used as a control. Six rats per group were sacrificed at 20, 40 and 60days, and the gingivae were obtained. The expression of TGF-β1, E-Cadherin, ZEB1, ZEB2, and Snail1 were examined by quantitative real time PCR (qRT-PCR), western blotting, and immunohistochemistry. In addition, a group of microRNAs associated with EMT and fibrosis were also detected in gingival tissue by qRT-PCR.

RESULTS

The mRNA and protein levels of TGF-β1, ZEB1, and ZEB2 in gingivae were significantly upregulated after 40 and 60days of CsA administration. Conversely, the levels of E-cadherin were significantly downregulated in overgrowth sample at day 40 and 60. Intense immunohistochemmical staining for TGF-β1 were observed in the samples from CsA group at day 40 and 60. Concomitantly, the densities of E-cadherin were gradually decreased in the basal layers of epithelium with time. Three members of miR-200s (miR-200a, miR-200b and miR-200c) were significantly downregulated in CsA-treated rats at 40 and 60days, while miR-9, miR-23a and miR-155 were significantly upregulated when compared with those of the control group.

CONCLUSIONS

The process of EMT in CsA-induced rat gingival overgrowth is associated with increased expression of TGF-β1, ZEB1, and ZEB2, and decreased expression of E-cadherin.

Role of transforming growth factor-beta1 in cyclosporine-induced epithelial-to-mesenchymal transition in gingival epithelium

BACKGROUND

It has been proposed that cyclosporin A (CsA) may induce epithelial-to-mesenchymal transition (EMT) in gingiva. The aims of the present study are to confirm the notion that EMT occurs in human gingival epithelial (hGE) cells after CsA treatment and to investigate the role of transforming growth factor beta1 (TGF-β1) on this CsA-induced EMT.

METHODS

The effects of CsA, with and without TGF-β1 inhibitor, on the morphologic changes of primary culture of hGE cells were examined in vitro. The changes of protein and messenger RNA (mRNA) expressions of two EMT markers (E-cadherin and alpha-smooth muscle actin) in the hGE cells after CsA treatment with and without TGF-β1 inhibitor were evaluated with immunocytochemistry and real-time polymerase chain reaction.

RESULTS

The epithelial cells became spindle-like, elongated, and disassociated from neighboring cells and lost their original cobblestone monolayer pattern when CsA was added. However, the epithelial cells stayed in their original cobblestone morphology with treatment of TGF-β1 inhibitor on top of the CsA treatment. When CsA was given, the protein and mRNA expressions of E-cadherin and α-SMA were significantly altered, and these alterations were significantly reversed with pretreatment of TGF-β1 inhibitor.

CONCLUSIONS

CsA could induce Type 2 EMT in gingiva by changing the morphology of epithelial cells and altering the EMT markers/effectors. The CsA-induced gingival EMT is dependent or at least partially dependent on TGF-β1.

Mechanism of drug-induced gingival overgrowth revisited: a unifying hypothesis

Drug-induced gingival overgrowth (DIGO) is a disfiguring side effect of anti-convulsants, calcineurin inhibitors, and calcium channel blocking agents. A unifying hypothesis has been constructed which begins with cation flux inhibition induced by all three of these drug categories. Decreased cation influx of folic acid active transport within gingival fibroblasts leads to decreased cellular folate uptake, which in turn leads to changes in matrix metalloproteinases metabolism and the failure to activate collagenase. Decreased availability of activated collagenase results in decreased degradation of accumulated connective tissue which presents as DIGO. Studies supporting this hypothesis are discussed.

Cyclosporine A up-regulates Sonic hedgehog in gingiva: role of the up-regulation on gingival cell proliferation

BACKGROUND AND OBJECTIVE

Sonic hedgehog protein (SHH) is a mitogen that stimulates cell proliferation. Cyclosporine A enhances the proliferation of gingival cells; however, the relationships of SHH to cyclosporine A or to cyclosporine A-enhanced gingival cell proliferation have not been described.

MATERIAL AND METHODS

Here, we investigated SHH expression in gingiva in vitro and in vivo after cyclosporine A treatment and tested the effect of SHH inhibition on cyclosporine A-enhanced gingival fibroblast proliferation in vitro.

RESULTS

In human gingival fibroblasts, cyclosporine A treatment increased the expression of SHH transcripts and SHH protein, and stimulated cell proliferation; the addition of cyclopamine, an SHH signaling inhibitor, suppressed cyclosporine A-enhanced cell proliferation. Up-regulated expression of SHH and up-regulation of proliferating cell nuclear antigen transcripts and protein were observed in the edentulous gingiva of cyclosporine A-treated rats.

CONCLUSION

Cyclosporine A up-regulates gingival SHH expression in vitro and in vivo, and the inhibition of the SHH pathway counteracts the stimulatory effect of cyclosporine A on gingival fibroblast proliferation. Therefore, we suggest that SHH mediates a novel molecular mechanism for cyclosporine A-induced gingival complications.

Crosstalk between Shh and TGF-β signaling in cyclosporine-enhanced cell proliferation in human gingival fibroblasts

BACKGROUND

Immunosuppressant cyclosporine-A induces gingival hyperplasia, which is characterized by increased fibroblast proliferation and overproduction of extracellular matrix components and regulated by transforming growth factor-beta (TGF-β). The TGF-β and Sonic hedgehog (Shh) pathways both mediate cell proliferation. Crosstalk between these pathways in cancer has recently been proposed, but the hierarchical pattern of this crosstalk remains unclear. In normal fibroblasts, a TGF-β-stimulating Shh pattern was observed in induced fibrosis. However, Shh pathway involvement in cyclosporine-enhanced gingival proliferation and the existence of crosstalk with the TGF-β pathway remain unclear.

METHODOLOGY/PRINCIPAL FINDINGS

Cyclosporine enhanced mRNA and protein levels of TGF-β and Shh in human gingival fibroblasts (RT-PCR and western blotting). A TGF-β pathway inhibitor mitigated cyclosporine-enhanced cell proliferation and an Shh pathway inhibitor attenuated cyclosporine-enhanced proliferation in fibroblasts (MTS assay and/or RT-PCR of PCNA). Exogenous TGF-β increased Shh expression; however, exogenous Shh did not alter TGF-β expression. The TGF-β pathway inhibitor mitigated cyclosporine-upregulated Shh expression, but the Shh pathway inhibitor did not alter cyclosporine-upregulated TGF-β expression.

CONCLUSIONS/SIGNIFICANCE

The TGF-β and Shh pathways mediate cyclosporine-enhanced gingival fibroblast proliferation. Exogenous TGF-β increased Shh expression, and inhibition of TGF-β signaling abrogated the cyclosporine-induced upregulation of Shh expression; however, TGF-β expression appeared unchanged by enhanced or inhibited Shh signaling. This is the first study demonstrating the role of Shh in cyclosporine-enhanced gingival cell proliferation; moreover, it defines a hierarchical crosstalk pattern in which TGF-β regulates Shh in gingival fibroblasts. Understanding the regulation of cyclosporine-related Shh and TGF-β signaling and crosstalk in gingival overgrowth will clarify the mechanism of cyclosporine-induced gingival enlargement and help develop targeted therapeutics for blocking these pathways, which can be applied in pre-clinical and clinical settings.