The biological mechanisms of PCNA and BMP in TMJ adaptive remodeling

Exploring the genetic expression of Sdf1, Foxc1 and histologic changes following mandibular advancement and recovery phase in Wistar rats

PURPOSE

This study evaluated the impact of mandibular advancement on Sdf1 and Foxc1 gene expression in the mandibular condylar cartilage of young Wistar rats. By examining the changes that occur during a unique one-month recovery period, it highlights the critical role of gene expression and condylar adaptation during the recovery phase. The analysis focused on whether, during the recovery period, reversal changes occur when functional appliances are removed and whether genetic expression important for condyle growth and adaptation downregulates.

MATERIAL AND METHODS

The study involved 30 male Wistar rats divided into 2 control groups Appliance Control and Recovery Control groups, and 2 experimental groups, the Appliance group with mandibular advancement bite-jumping appliance for 30 days, and the Recovery group with appliance for 30 days followed by a 30-day recovery. Molecular analysis of condylar cartilage using real-time RT-PCR and histological assessments was conducted.

RESULTS

Significant genetic expression alterations were noted in both the experimental groups for Sdf1 (p < 0.05) and Foxc1 (p < 0.05). According to histological investigations, significant alterations with an increase in the proliferative and hypertrophic layer in condylar cartilage were seen.

CONCLUSION

Mandibular advancement bite-jumping appliances induce proliferative and hypertrophic layer changes in mandibular condylar cartilage, shown by elevated Foxc1 levels and decreased Sdf1 levels. Post-appliance removal, persistent gene expression reveals a true joint stimulation.

Investigation of polymorphisms in BMP2, BMP4, SMAD6 and RUNX2 genes and pulp stones

This study aimed to assess the association between genetic polymorphisms in BMP2 (rs1005464 and rs235768), BMP4 (rs17563), SMAD6 (rs2119261 and rs3934908) and RUNX2 (rs59983488 and rs1200425) and pulp stones (PS). A total of 117 participants, consisting of 63 individuals with PS and 54 without PS, were included. Digital radiographs and a demographic/clinical questionnaire were used. Genomic DNA from salivary cells was genotyped via real-time polymerase chain reaction. Statistical analyses, including Chi-Square, Fisher's exact tests, Poisson regression and dimensionality reduction, were conducted. The rs2119261 polymorphism in the SMAD6 gene showed an association with genotype distribution in the recessive model (p = 0.049). The T-T haplotype in the SMAD6 gene (rs2119261 and rs3934908) was more prevalent in the control group and significantly linked with PS (p = 0.029). No associations were found between PS risk and genetic polymorphisms in BMP2, BMP4 and RUNX2. Polymorphisms in the SMAD6 gene were associated with PS.

Phytocompounds from the medicinal and dietary plants: Multi-target agents for cancer prevention and therapy

Cervical cancer is the fourth leading cause of cancer death among women worldwide. Due to cervical cancer's high incidence and mortality, there is an unmet demand for effective diagnostic, therapeutic, and preventive agents. At present, the preferred treatment strategies for advanced metastatic cervical cancer include surgery, radiotherapy, and chemotherapy. However, cervical cancer is gradually developing resistance to chemotherapy, thereby reducing its efficacy. Over the last several decades, phytochemicals, a general term for compounds produced from plants, have gained attention for their role in preventing cervical cancer. This role in cervical cancer prevention has garnered attention on the medicinal properties of fruits and vegetables. Phytochemicals are currently being evaluated for their ability to block proteins involved in carcinogenesis and chemoresistance against cervical cancer. Chemoresistance to cancer drugs like cisplatin, doxorubicin, and 5-fluorouracil has become a significant limitation of drug-based chemotherapy. However, the combination of cisplatin with other phytochemicals has been identified as a promising alternative to subjugate cisplatin resistance. Phytochemicals are promising chemo-preventive and chemotherapeutic agents as they possess antioxidant, anti-inflammatory, and anti-proliferative potential against many cancers, including cervical cancer. Furthermore, the ability of the phytochemicals to modulate cellular signaling pathways through up and down regulation of various proteins has been claimed for their therapeutic potential. Phytochemicals also display a wide range of biological functions, including cell cycle arrest, apoptosis induction, inhibition of invasion, and migration in cervical cancer cells. Numerous studies have revealed the critical role of different signaling proteins and their signaling pathways in the pathogenesis of cervical cancer. Here, we review the ability of several dietary phytochemicals to alter carcinogenesis by modulating various molecular targets.

595-nm pulsed dye laser combined with fractional CO2 laser reduces hypertrophic scar through down-regulating TGFβ1 and PCNA

595-nm pulsed dye laser and fractional CO2 laser have been demonstrated effective to treat hypertrophic scar. The underlying mechanism may involve transforming growth factor-beta1 (TGFβ1) and proliferating cell nuclear antigen (PCNA), but remains to be clarified. Our study was performed to investigate how 595-nm pulsed dye laser combined with fractional CO2 laser treats hypertrophic scars in a rabbit model through regulating the expression of TGFβ1 and PCNA. Twenty-four New Zealand white rabbits were randomly divided into control group, pulsed dye laser group, fractional CO2 laser group, and pulsed dye laser + fractional CO2 laser (combination) group. Surgical wounds were made and allowed to grow into hypertrophic scars at day 28. Next, 595-nm pulsed dye laser (fluence: 15 J/cm2; square: 7 mm; pulse duration: 10 ms) was used in pulsed dye laser and combination group, while fractional CO2 laser (combo mode, deep energy: 12.5 mJ; super energy: 90 mJ) in fractional CO2 laser and combination groups, once every 4 weeks for 3 times. The appearance and thickness of hypertrophic scar samples were measured with hematoxylin-eosin and Van Gieson's straining. The expressions of TGFβ1 and PCNA were evaluated by immunohistochemical and western blot analysis. A significant improvement was noted in the thickness, size, hardness, and histopathology of hypertrophic scar samples after laser treatment, especially in combination group. Scar Elevation Index (SEI), fiber density (NA), and collagen fiber content (AA) decreased most significantly in combination group (2.10 ± 0.14; 2506 ± 383.00; 22.98 ± 2.80%) compared to 595-nm pulsed dye laser group (3.35 ± 0.28; 4857 ± 209.40; 42.83 ± 1.71%) and fractional CO2 laser group (2.60 ± 0.25; 3995 ± 224.20; 38.33 ± 3.01%) (P < 0.001). Furthermore, TGFβ1 and PCNA expressions were more suppressed in combination group (8.78 ± 1.03; 7.81 ± 1.51) than in 595-nm pulsed dye laser (14.91 ± 1.68; 15.73 ± 2.53) and fractional CO2 laser alone group (15.96 ± 1.56; 16.13 ± 1.72) (P < 0.001). The combination of 595-nm pulsed dye laser with fractional CO2 laser can improve the morphology and histology of hypertrophic scars in a rabbit model through inhibiting the expression of TGFβ1 and PCNA protein. Our findings can pave the way for new clinical treatment strategies for hypertrophic scars.

Effect of Artesunate Combined With Fractional CO2 Laser on the Hypertrophic Scar in a Rabbit Model

BACKGROUND AND OBJECTIVES

Hypertrophic scar (HS), a common complication in wound healing, is characterized by the disarrangement of collagen, fibers, and extracellular matrix. Artesunate (ART) can inhibit the abnormal formation of fibroblasts and collagens. Fractional CO2 laser (FCO2 L) can facilitate tissue remodeling and the absorption of drugs into ablative microthermal columns in HS. So far, no research has investigated the efficacy of ART combined with an FCO2 L in treating HS. To investigate the theoretical basis and clinical significance of this combination, we established a rabbit model of HS to observe the change in the expression of transforming growth factor β1 (TGF-β1) and proliferating cell nuclear antigen (PCNA).

STUDY DESIGN/MATERIALS AND METHODS

Forty New Zealand white rabbits were randomly divided into four groups: control group, ART group, FCO2 L group, and ART + FCO2 L (combination) group. Four wounds were surgically established in the ear of each rabbit and allowed to develop into HS. ART (20 μL/cm2 ) was injected in ART and combination groups, and FCO2 L (combo mode, deep energy:10m J, super energy: 50 mJ) in FCO2 L and combination groups on the 28th day after HS occurred. Three rounds of treatment were applied (once every 14 days). HS samples were measured by hematoxylin and eosin staining, Van Gieson staining, immunohistochemistry, and Western blot analysis on the 70th day.

RESULTS

The morphological and histopathological changes in HS were significant. HSs were smoother and smaller and the collagen fibers were thinner and less disordered in the combination group than those in ART and FCO2 L groups. Meanwhile, the hypertrophic index (HI), fiber density (NA), and collagen fiber content (AA) were lower in the combination group (1.54 ± 0.15, 3.30 ± 0.22, 30.37 ± 1.41%) than in the ART group (2.51 ± 0.22, 4.69 ± 0.16, 44.68 ± 2.30%) and FCO2 L group (1.99 ± 0.14, 4.13 ± 0.12, 37.74 ± 1.38%) (P < 0.01). Additionally, the expressions of TGF-β1 and PCNA protein were suppressed in the ART group (0.30 ± 0.03, 0.25 ± 0.03) and FCO2 L group (0.35 ± 0.03, 0.32 ± 0.05), and the suppression was more significant in the combination group(0.07 ± 0.02, 0.07 ± 0.02) (P < 0.01).

CONCLUSIONS

The combination of ART and FCO2 L can effectively reduce HS in the rabbit model. This is the first report about this combination in the treatment of HS. A novel treatment is expected to be based on our findings. Lasers Surg. Med. © 2021 Wiley Periodicals LLC.

Investigation of Genetic Polymorphisms in BMP2, BMP4, SMAD6, and RUNX2 and Persistent Apical Periodontitis

INTRODUCTION

This study aimed to evaluate the interplay among single-nucleotide polymorphisms (SNPs) in the encoding genes BMP2, BMP4, SMAD6, and RUNX2 in persistent apical periodontitis (PAP).

METHODS

In this multicentric study, 272 patients diagnosed with pulp necrosis with apical periodontitis before root canal therapy who attended regular follow-up visits for at least 1 year were screened. Periapical radiographs and clinical aspects were evaluated, and the participants were classified as PAP (n = 110) or repaired (n = 162). Genomic DNA was used for the genotyping of the following SNPs: rs1005464 and rs235768 in bone morphogenetic protein 2 (BMP2), rs17563 in bone morphogenetic protein 4 (BMP4), rs2119261 and rs3934908 in SMAD family member 6 (SMAD6), and rs59983488 and rs1200425 in runt-related transcription factor 2 (RUNX2). The chi-square test was used to compare genotype distributions between groups. The multifactor dimensionality reduction method was applied to identify SNP-SNP interactions. The alpha for all the analysis was 5%.

RESULTS

The multifactor dimensionality reduction suggested the rs235768 in BMP2 and rs59983488 in RUNX2 as the best SNP-SNP interaction model (cross-validation = 10/10, testing balanced accuracy = 0.584, P = .026) followed by rs17563 in BMP4 and rs2119261 in SMAD6 (cross validation = 10/10, testing balanced accuracy = 0.580, P = .031). In the rs235768 in BMP2 and rs59983488 in RUNX2 model, the high-risk genotype was TT + TT (odds ratio = 4.36; 95% confidence interval, 0.44-42.1). In model rs17563 in BMP4 and rs2119261 in SMAD6, GG + TT (odds ratio = 2.63; 95% confidence interval, 0.71-11.9) was the high-risk genotype.

CONCLUSIONS

The interactions between rs235768 in BMP2 and rs59983488 in RUNX2 and between rs17563 in BMP4 and rs2119261 in SMAD6 are associated with PAP, suggesting that an interplay of these SNPs is involved in the higher risk of developing PAP.

MiR-147 inhibits cyclic mechanical stretch-induced apoptosis in L6 myoblasts via ameliorating endoplasmic reticulum stress by targeting BRMS1

Functional orthopedic treatment is effective for the correction of malformation. Studies demonstrated myoblasts undergo proliferation and apoptosis on certain stretch conditions. MicroRNAs (miRNAs) function in RNA silencing and post-transcriptional regulation of gene expression, and participate in various biological processes, including proliferation and apoptosis. One hypothesis suggested that miRNA was involved into the procedure via suppressing its target genes then triggered endoplasmic reticulum stress-induced apoptosis. Therefore, miRNAs play important roles in the regulation of the proliferation and apoptosis of myoblasts. In our study, the miR-147 has been explored. A cyclic mechanical stretch model was established to observe the features of rat L6 myoblasts. The detection of mRNA and protein levels was performed by qRT-PCR and western blot. L6 cell proliferation/apoptosis was checked by CCK-8 assay, DNA fragmentation assay, and caspase-3 activity assay. MiRNA transfections were performed as per the manufacturer's suggestions: (1) cyclic mechanical stretch induced apoptosis of L6 myoblasts and inhibition of miR-147; (2) miR-147 attenuated cyclic mechanical stretch-induced apoptosis of L6 myoblasts; (3) miR-147 attenuated cyclic mechanical stretch-induced L6 myoblast endoplasmic reticulum stress; (4) BRMS1 was a direct target of miR-147 in L6 myoblasts; (5) miR-147/BRMS1 axis participated in the regulation of cyclic mechanical stress on L6 myoblasts. MiR-147 attenuates endoplasmic reticulum stress by targeting BRMS1 to inhibit cyclic mechanical stretch-induced apoptosis of L6 myoblasts.

Gamma-Tocotrienol Stimulates the Proliferation, Differentiation, and Mineralization in Osteoblastic MC3T3-E1 Cells

Gamma-tocotrienol, a major component of tocotrienol-rich fraction of palm oil, has been suggested to exhibit bone protective effectsin vivo. However, the effects ofγ-tocotrienol on osteoblast cells are still unclear. In this study, the effects ofγ-tocotrienol on the proliferation, differentiation, and mineralization in osteoblastic MC3T3-E1 cells were investigated. Our results showed thatγ-tocotrienol (2–8 μmol/L) significantly improved the cell proliferation (p<0.05), but it did not affect cell cycle progression.γ-Tocotrienol significantly increased alkaline phosphatase (ALP) activity (p<0.05), secretion levels of osteocalcin (OC) and osteonectin (ON), and mRNA levels of collagen type I (Col I) of MC3T3-E1 cells. Meanwhile, we found thatγ-tocotrienol is promoted in differentiation MC3T3-E1 cells by upregulation of the expression of Runx2 protein. Moreover, the number of bone nodules increased over 2.5-fold in cells treated withγ-tocotrienol (2–8 μmol/L) for 24 d compared to control group. These results indicated thatγ-tocotrienol at low dose levels, especially 4 μmol/L, could markedly enhance the osteoblastic function by increasing the proliferation, differentiation, and mineralization of osteoblastic MC3T3-E1 cells. Moreover, our data also indicated that Runx2 protein may be involved in these effects. Further studies are needed to determine the potential ofγ-tocotrienol as an antiosteoporotic agent.

γ-Tocotrienol Inhibits Proliferation and Induces Apoptosis Via the Mitochondrial Pathway in Human Cervical Cancer HeLa Cells

γ-Tocotrienol, a kind of isoprenoid phytochemical, has antitumor activity. However, there is limited evidence that it has an effect on cervical cancer. In this study, the capacity to inhibit proliferation and induce apoptosis in human cervical cancer HeLa cells and the mechanism underlying these effects were examined. The results indicated that a γ-tocotrienol concentration over 30 μM inhibited the growth of HeLa cells with a 50% inhibitory concentration (IC₅₀) of 46.90 ± 3.50 μM at 24 h, and significantly down-regulated the expression of proliferative cell nuclear antigen (PCNA) and Ki-67. DNA flow cytometric analysis indicated that γ-tocotrienol arrested the cell cycle at G0/G1 phase and reduced the S phase in HeLa cells. γ-tocotrienol induced apoptosis of HeLa cells in a time- and dose-dependent manner. γ-tocotrienol-induced apoptosis in HeLa cells was accompanied by down-regulation of Bcl-2, up-regulation of Bax, release of cytochrome from mitochondria, activation of caspase-9 and caspase-3, and subsequent poly (ADP-ribose) polymerase (PARP) cleavage. These results suggested that γ-tocotrienol could significantly inhibit cell proliferation through G0/G1 cell cycle arrest, and induce apoptosis via the mitochondrial apoptotic pathway in human cervical cancer HeLa cells. Thus, our findings revealed that γ-tocotrienol may be considered as a potential agent for cervical cancer therapy.

Bone fracture in a rat femoral fracture model is associated with the activation of autophagy

Autophagy, which is a mechanism for the turnover of intracellular molecules and organelles, protects cells during stress responses; however, the role of autophagy in the stages of bone fracture remains to be elucidated. The aim of the present study was to investigate the process of autophagy in bone tissue at different time-points after fracture. A femur fracture model was established in male adult Wistar rats via surgery. The protein expression of microtubule-associated protein II light chain 3 (LC3-II) was analyzed in a femur fracture (experimental) group and a sham-surgery group using immunofluorescence. The protein expression of proliferating cell nuclear antigen (PCNA) was used to investigate the cell proliferation in bone tissue following fracture via immunohistochemical analysis. The correlation between cell proliferation and autophagy was analyzed using linear regression. LC3-II protein was constitutively expressed in the sham-surgery group; however, compared with the expression in the sham-surgery group, the LC3-II expression in the experimental group was significantly increased at each time-point (P<0.05). Similarly, immunohistochemistry revealed that the number of PCNA-positive cells in each section was significantly increased following fracture injury (P<0.01). A comparison of the LC3-II- and PCNA-positive rates in the experimental group rats at each time-point revealed a linear correlation (R²=0.43, P<0.01). In conclusion, surgically induced fracture in rats is associated with an increase in LC3-II and PCNA protein expression during the initial stages of fracture injury, and a correlation exists between the expression of the two proteins. These results suggest that potential treatment aimed at improving fracture healing should target the process of autophagy.

Adjunctive techniques for enhancing mandibular growth in Class II malocclusion

Class II malocclusions are generally characterized by mandible retrusion. For this reason, forward bite jumping appliances, also known as functional appliances were originally designed to enhance mandibular forward projection. However, there is still insufficient evidence to support the effectiveness, predictability and stability of functional appliances in modifying mandibular growth. This article was aimed at presenting evidences and hypotheses that mandibular growth may be enhanced through the use of adjunctive methods in conjunction with functional appliances. In formulating our hypothesis, we considered relevant data, mostly derived from animal studies, concerning alternative methods, such as low-intensity ultrasound and light-emitting diode, as well as their related cellular and molecular mechanisms. According to the evidences covered in this article, we suggest that both methods are potentially effective, and theoretically able to act in synergistic way to enhance functional appliances treatment on mandibular and condylar additional growth. The rationale for the use of these methods as adjunctive therapies for mandibular underdevelopment is attributed to their abilities on stimulating angiogenesis, cell differentiation, proliferation, and hypertrophy, as well as enhancing matrix production and endochondoral bone formation, especially on the condyle of growing animals. This article also proposed a study design which would be able to either prove or refute our hypothesis. If ratified, it would represent a significant scientific accomplishment which provides support for further investigations to be carried out on well-designed clinical trials.

The biology of TMJ growth modification: a review

Several studies have indicated a positive response of the temporomandibular joint (TMJ) to mandibular advancement, while others have reported that TMJ adaptive responses are non-existent and negligible. Controversy continues to grow over the precise nature of skeletal changes that occur during mandibular growth modification, due to an apparent lack of tissue markers required to substantiate the precise mechanism by which this is occurring. However, evidence suggests that orthopedic forces clinically modify the growth of the mandible. To further our knowledge about the effect of orthopedic treatment on the TMJ, it is necessary that we understand the biologic basis behind the various tissues involved in the TMJ's normal growth and maturation. The importance of this knowledge is to consider the potential association between TMJ remodeling and mandibular repositioning under orthopedic loading. Considerable histologic and biochemical research has been performed to provide basic information about the nature of skeletal growth modification in response to mandibular advancement. In this review, the relevant histochemical evidence and various theories regarding TMJ growth modification are discussed. Furthermore, different regulatory growth factors and tissue markers, which are used for cellular and molecular evaluation of the TMJ during its adaptive response to biomechanical forces, are underlined.

hRpn13, a newly identified component of the 19S particle, regulates proliferation, differentiation, and function in the human osteoblast-like cell line MG63. [corrected]

The 26S proteasome is a key component of the ubiquitin-proteasome system, a process responsible for the majority of cellular protein degradation. The function of the proteasomal ubiquitin receptor hRpn13, a component of the 26S proteasome, is not completely understood. To investigate the role of hRpn13 in the ubiquitin-proteasome system in osteoblasts, the effects of suppressing and overexpressing the hRpn13 gene on proliferation, differentiation, and function of human osteoblast-like MG63 cells were examined. After knockdown of hRpn13 by small interfering RNA, changes in osteoblast proliferation were evaluated by methyl-thiazolyl-tetrazolium assay. There was an increase in markers for osteoblast proliferation, specifically alkaline phosphatase activity, and elevated protein levels of osteocalcin, proliferating cell nuclear antigen (PCNA), and ubiquitin. Furthermore, hRpn13 knockdown also resulted in a decrease in the ratio between the gene expressions of RANKL and OPG, key players in the pathogenesis of bone diseases that influence the normal balance between bone formation and resorption. In contrast, overexpression of hRpn13 inhibited the proliferation of MG63 cells, and decreased alkaline phosphatase activity as well as protein levels of osteocalcin, PCNA, and ubiquitin while the ratio of RANKL to OPG expression increased. To confirm the function of hRpn13 in the ubiquitin-proteasome pathway, osteoblast proliferation enhancement and ubiquitin accumulation after hRpn2 knockdown was assessed. The results suggest that overexpression of hRpn13 negatively influences proliferation and osteogenic differentiation in MG63 cells. The evidence implies that hRpn13 modulates the influence of osteoblasts on osteoclasts by controlling the stability of regulatory proteins in osteoblasts. In summary, overexpression of hRpn13 promoted the activity of the ubiquitin-proteasome system.