Exosome: an overview on enhanced biogenesis by small molecules

Exosomes are extracellular vesicles that received attention for their potential use in the treatment of various injuries. They communicate intercellularly by transferring genetic and bioactive molecules from parent cells. Although exosomes hold immense promise for treating neurodegenerative and oncological diseases, their actual clinical use is very limited because of their biogenesis and secretion. Recent studies have shown that small molecules can significantly enhance exosome biogenesis, thereby remarkably improving yield, functionality, and therapeutic effects. These molecules modulate critical pathways toward optimum exosome production in a mode that is either ESCRT dependent or ESCRT independent. Improved exosome biogenesis may provide new avenues for targeted cancer therapy, neuroprotection in neurodegenerative diseases, and regenerative medicine in wound healing. This review explores the role of small molecules in enhancing exosome biogenesis and secretion, highlights their underlying mechanisms, and discusses emerging clinical applications. By addressing current challenges and focusing on translational opportunities, this study provides a foundation for advancing cell-free therapies in regenerative medicine and beyond.

Single nucleotide polymorphism rs854560 in paraoxonase-1 regulates the cytodifferentiation of human periodontal ligament cells

Aggressive periodontitis (AgP), classified as Stages III or IV and grade C periodontitis, is characterized by the rapid destruction of periodontal tissue. Genetic factors contribute to the pathogenesis of this disease, and familial aggregation of periodontitis is often observed. However, the mechanisms underlying the onset or progression of AgP have not been elucidated. Previously, we performed exome sequencing and identified AgP risk factors in Japanese AgP-patients. However, the small sample size limited our scope for detecting some of the true AgP genetic risk factors. To overcome this limitation, we searched for AgP-related genes more comprehensively from the whole exome sequencing data of the Japanese AgP-patients by extending the filtering criteria range. We identified seven AgP-associated suggestive genes, including the single nucleotide polymorphism (SNP) rs854560 in paraoxonase-1 (PON-1), which is correlated with AgP. However, the mechanism(s) underlying the induction of AgP pathogenesis by the SNP rs854560 PON-1 has not been elucidated. Thus, we further analyzed the functions of the SNP rs854560 PON-1 in human periodontal ligament (HPDL) cells through transfection of the wild-type PON-1 (WT) or SNP rs854560 PON-1 (mut) into HPDL cells. Real-time PCR indicated that mut had higher mRNA expression of osteogenic related-genes and showed a higher tendency of ALP activity and proliferation. The result suggested that WT PON-1 contributes to periodontal tissue homeostasis through appropriate proliferation and cytodifferentiation of HPDL cells, while SNP rs854560 PON-1 may mediate excessive calcification of periodontal tissue due to hyper proliferation of HPDL cells, thereby increasing the risk of AgP.

Therapeutic Effects of Hinokitiol through Regulating the SIRT1/NOX4 against Ligature-Induced Experimental Periodontitis

Hinokitiol (HKT) is one of the essential oil components found in the heartwood of Cupressaceae plants, and has been reported to have various bioactive effects, including anti-inflammatory effects. However, the improving effect of HKT on periodontitis, which is characterized by periodontal tissue inflammation and alveolar bone loss, has not been clearly revealed. Therefore, we investigated the periodontitis-alleviating effect of HKT and the related molecular mechanisms in human periodontal ligament cells. According to the study results, HKT downregulated SIRT1 and NOX4, which were increased by Porphyromonas gingivalis Lipopolysaccharide (PG-LPS) stimulation and were found to regulate pro-inflammatory mediators and oxidative stress through SIRT1/NOX4 signals. Additionally, by increasing the expression of osteogenic makers such as alkaline phosphatase, osteogenic induction of human periodontal ligament (HPDL) cells, which had been reduced by PG-LPS, was restored. Furthermore, we confirmed that NOX4 expression was regulated through regulation of SIRT1 expression with HKT. The in vitro effect of HKT on improving periodontitis was proven using the periodontal inflammation model, which induces periodontal inflammation using ligature, a representative in vivo model. According to in vivo results, HKT alleviated periodontal inflammation and restored damaged alveolar bone in a concentration-dependent manner in the periodontal inflammation model. Through this experiment, the positive effects of HKT on relieving periodontal tissue inflammation and recovering damaged alveolar bone, which are important treatment strategies for periodontitis, were confirmed. Therefore, these results suggest that HKT has potential in the treatment of periodontitis.

Identification of disease-associate variants of aggressive periodontitis using genome-wide association studies

Aggressive periodontitis (AgP), Stage III or IV and Grade C according to the new periodontitis classification, is characterized by the rapid destruction of periodontal tissues in the systemically healthy population and often causes premature tooth loss. The presence of familial aggregation suggests the involvement of genetic factors in the pathogenesis. However, the genes associated with the onset and progression of the disease and details of its pathogenesis have not yet been fully identified. In recent years, the genome-wide approach (GWAS), a comprehensive genome analysis method using bioinformatics, has been used to search for disease-related genes, and the results have been applied in genomic medicine for various diseases, such as cancer. In this review, we discuss GWAS in the context of AgP. First, we introduce the relationship between single-nucleotide polymorphisms (SNPs) and susceptibility to diseases and how GWAS is useful for searching disease-related SNPs. Furthermore, we summarize the recent findings of disease-related genes using GWAS on AgP inside and outside Japan and a possible mechanism of the pathogenesis of AgP based on available literature and our research findings. These findings will lead to advancements in the prevention, prognosis, and treatment of AgP.

Lipase-a single-nucleotide polymorphism rs143793106 is associated with increased risk of aggressive periodontitis by negative influence on the cytodifferentiation of human periodontal ligament cells

BACKGROUND AND OBJECTIVE

Aggressive periodontitis (AgP) is characterized by general health and rapid destruction of periodontal tissue. The familial aggregation of this disease highlights the involvement of genetic factors in its pathogeny. We conducted a genome-wide association study (GWAS) to identify AgP-related genes in a Japanese population, and the lipid metabolism-related gene, lipase-a, lysosomal acid type (LIPA), was suggested as an AgP candidate gene. However, there is no report about the expression and function(s) of LIPA in periodontal tissue. Hence, we studied the involvement of how LIPA and its single-nucleotide polymorphism (SNP) rs143793106 in AgP by functional analyses of LIPA and its SNP in human periodontal ligament (HPDL) cells.

MATERIALS AND METHODS

GWAS was performed using the genome database of Japanese AgP patients, and the GWAS result was confirmed using Sanger sequencing. We examined the mRNA expression level of LIPA and the protein expression level of the encoded protein lysosomal acid lipase (LAL) in periodontium-composing cells using conventional and real-time polymerase chain reaction (PCR) and western blotting, respectively. Lentiviral vectors expressing LIPA wild-type (LIPA WT) and LIPA SNP rs143793106 (LIPA mut) were transfected into HPDL cells. Western blotting was performed to confirm the transfection. LAL activity of transfected HPDL cells was determined using the lysosomal acid lipase activity assay. Transfected HPDL cells were cultured in mineralization medium. During the cytodifferentiation of transfected HPDL cells, mRNA expression of calcification-related genes, alkaline phosphatase (ALPase) activity and calcified nodule formation were assessed using real-time PCR, ALPase assay, and alizarin red staining, respectively.

RESULTS

The GWAS study identified 11 AgP-related candidate genes, including LIPA SNP rs143793106. The minor allele frequency of LIPA SNP rs143793106 in AgP patients was higher than that in healthy subjects. LIPA mRNA and LAL protein were expressed in HPDL cells; furthermore, they upregulated the cytodifferentiation of HPDL cells. LAL activity was lower in LIPA SNP-transfected HPDL cells during cytodifferentiation than that in LIPA WT-transfected HPDL cells. In addition, ALPase activity, calcified nodule formation, and calcification-related gene expression levels were lower during cytodifferentiation in LIPA SNP-transfected HPDL cells than those in LIPA WT-transfected HPDL cells.

CONCLUSION

LIPA, identified as an AgP-related gene in a Japanese population, is expressed in HPDL cells and is involved in regulating cytodifferentiation of HPDL cells. LIPA SNP rs143793106 suppressed cytodifferentiation of HPDL cells by decreasing LAL activity, thereby contributing to the development of AgP.

A deep learning approach to automatic gingivitis screening based on classification and localization in RGB photos

Routine dental visit is the most common approach to detect the gingivitis. However, such diagnosis can sometimes be unavailable due to the limited medical resources in certain areas and costly for low-income populations. This study proposes to screen the existence of gingivitis and its irritants, i.e., dental calculus and soft deposits, from oral photos with a novel Multi-Task Learning convolutional neural network (CNN) model. The study can be meaningful for promoting the public dental health, since it sheds light on a cost-effective and ubiquitous solution for the early detection of dental issues. With 625 patients included in this study, the classification Area Under the Curve (AUC) for detecting gingivitis, dental calculus and soft deposits were 87.11%, 80.11%, and 78.57%, respectively; Meanwhile, according to our experiments, the model can also localize the three types of findings on oral photos with moderate accuracy, which enables the model to explain the screen results. By comparing to general-purpose CNNs, we showed our model significantly outperformed on both classification and localization tasks, which indicates the effectiveness of Multi-Task Learning on dental disease detection. In all, the study shows the potential of deep learning for enabling the screening of dental diseases among large populations.

Protective roles of FICZ and aryl hydrocarbon receptor axis on alveolar bone loss and inflammation in experimental periodontitis

AIM

The aryl hydrocarbon receptor (AhR)-ligand axis has been shown to be involved in inflammatory diseases and bone homeostasis. However, the activation of AhR signalling pathway and the possible functions of AhR ligands in periodontitis are underexplored. This study investigated the expression of the AhR target gene cytochrome P450 subfamily B member 1 (CYP1B1) and the functions and mechanisms of the AhR ligand 6 formylindolo[3,2-b]carbazole (FICZ) in periodontitis.

MATERIALS AND METHODS

CYP1B1 expression was detected in human periodontitis samples, mice with ligature-induced periodontitis and lipopolysaccharide (LPS)-induced inflammation in periodontal ligament cells (PDLCs) in vitro. FICZ was administered topically or systemically. The therapeutic functions of FICZ were detected via qPCR, micro-computed tomography and immunohistochemistry. Finally, the mechanisms of AhR signalling in periodontitis were investigated by cell assays.

RESULTS

CYP1B1 expression was downregulated in periodontitis. FICZ rescued the alveolar bone loss and mitigated the inflammatory cytokines in periodontitis mice. In vitro, FICZ pre-treatment reduced the LPS-induced inflammation in PDLCs via the increased phosphorylation of STAT3. Additionally, FICZ prompted the mineralization of PDLCs via activation of the Wnt/β-catenin signalling pathway.

CONCLUSION

AhR signalling pathway is suppressed in periodontitis and the AhR ligand FICZ can prevent periodontitis.

Identification of genetic risk factors of aggressive periodontitis using genomewide association studies in association with those of chronic periodontitis

To identify the genetic risk factors for aggressive periodontitis (AgP), it is important to understand the progression and pathogenesis of AgP. The purpose of this review was to summarize the genetic risk factors for AgP identified through a case-control genomewide association study (GWAS) and replication study. The initial studies to identify novel AgP risk factors were potentially biased because they relied on previous studies. To overcome this kind of issue, an unbiased GWAS strategy was introduced to identify genetic risk factors for various diseases. Currently, three genes glycosyltransferase 6 domain containing 1 (GLT6D1), defensin α1 and α3 (DEFA1A3), and sialic acid-binding Ig-like lectin 5 (SIGLEC5) that reach the threshold for genomewide significance have been identified as genetic risk factors for AgP through a case-control GWAS.