Long non-coding RNA FER1L4 promotes osteogenic differentiation of human periodontal ligament stromal cells via miR-874-3p and vascular endothelial growth factor A

Static magnetic field contributes to osteogenic differentiation of hPDLSCs through the H19/Wnt/β-catenin axis

BACKGROUND

Static magnetic field (SMF) as an effective physical stimulus is capable of osteogenic differentiation for multiple mesenchymal stem cells, including human periodontal ligament stem cells (hPDLSCs). However, the exact molecular mechanism is still unknown. Therefore, this study intends to excavate molecular mechanisms related to SMF in hPDLSCs using functional experiments.

METHODS

hPDLSCs were treated with different intensities of SMF, H19 lentivirus, and Wnt/β-catenin pathway inhibitor (XAV939). Changes in osteogenic markers (Runx2, Col Ⅰ, and BMP2), Wnt/β-catenin markers (β-catenin and GSK-3β), and calcified nodules were examined using RT-qPCR, western blotting, and alizarin red staining in hPDLSCs.

RESULTS

SMF upregulated the expression of H19, and SMF and overexpressing H19 facilitated the expression of osteogenic markers (Runx2, Col Ⅰ, and BMP2), activation of the Wnt/β-catenin pathway, and mineralized sediment in hPDLSCs. Knockdown of H19 alleviated SMF function, and treatment with XAV939 limited SMF- and H19-mediated osteogenic differentiation of hPDLSCs. Notably, the expression of hsa-miR-532-3p, hsa-miR-370-3p, hsa-miR-18a-5p, and hsa-miR-483-3p in hPDLSCs was regulated by SMF, and may form an endogenous competitive RNA mechanism with H19 and β-catenin.

CONCLUSION

SMF contributes to the osteogenic differentiation of hPDLSCs by mediating the H19/Wnt/β-catenin pathway, and hsa-miR-532-3p, hsa-miR-370-3p, hsa-miR-18a-5p, and hsa-miR-483-3p may be the key factors in it.

Non-coding RNAs Function in Periodontal Ligament Stem Cells

Non-coding RNA has many types which has rich functions and plays an important role in the study of basic molecular mechanisms. Many non-coding RNA have important implications for pluripotent stem cells and embryonic stem cells. It has been found to affect the self-renewal and osteogenesis of many types of stem cells. They have also been found to regulate stem cell proliferation and induct bone differentiation. Periodontal ligament stem cells are essential for the regeneration of periodontal tissue. In recent years, in the field of stomatology, studies have found that many non-coding RNA also have significant regulatory effects on the proliferation and differentiation of periodontal stem cells and may become potential therapeutic targets for many common periodontal diseases such as periodontitis, bone/tooth/soft tissue loss and orthodontic treatment. Therefore, we summarized the current research status of non-coding RNA in the field of molecular mechanism of periodontal ligament stem cells and prospected its future progress.

Unraveling the molecular and immunological landscape: Exploring signaling pathways in osteoporosis

Osteoporosis, characterized by compromised bone density and microarchitecture, represents a significant global health challenge, particularly in aging populations. This comprehensive review delves into the intricate signaling pathways implicated in the pathogenesis of osteoporosis, providing valuable insights into the pivotal role of signal transduction in maintaining bone homeostasis. The exploration encompasses cellular signaling pathways such as Wnt, Notch, JAK/STAT, NF-κB, and TGF-β, all of which play crucial roles in bone remodeling. The dysregulation of these pathways is a contributing factor to osteoporosis, necessitating a profound understanding of their complexities to unveil the molecular mechanisms underlying bone loss. The review highlights the pathological significance of disrupted signaling in osteoporosis, emphasizing how these deviations impact the functionality of osteoblasts and osteoclasts, ultimately resulting in heightened bone resorption and compromised bone formation. A nuanced analysis of the intricate crosstalk between these pathways is provided to underscore their relevance in the pathophysiology of osteoporosis. Furthermore, the study addresses some of the most crucial long non-coding RNAs (lncRNAs) associated with osteoporosis, adding an additional layer of academic depth to the exploration of immune system involvement in various types of osteoporosis. Finally, we propose that SKP1 can serve as a potential biomarker in osteoporosis.

Unraveling the mechanism in l-Caldesmon regulating the osteogenic differentiation of PDLSCs: An innovative perspective

Maxillofacial bone defect is one of the common symptoms in maxillofacial, which affects the function and aesthetics of maxillofacial region. Periodontal ligament stem cells (PDLSCs) are extensively used in bone tissue engineering. The mechanism that regulates the osteogenic differentiation of PDLSCs remains not fully elucidated. Previous studies demonstrated that l-Caldesmon (l-CALD, or CALD1) might be involved in the osteogenic differentiation of PDLSCs. Here, the mechanism by which CALD1 regulates the osteogenic differentiation of PDLSCs is investigated. The osteogenic differentiation of PDLSCs is enhanced with Cald1 knockdown. Whole transcriptome sequencing (RNA-seq) analysis shows that bone morphogenetic proteins (BMP) signaling pathway and Wingless type (Wnt) pathway have significant change with Cald1 knockdown, and the expressions of Wnt-induced secreted protein 1 (WISP1), BMP2, Smad1/5/9, and p-Smad1/5/9 are significantly upregulated, while Glycogen synthase kinase 3β (GSK3β) and p-GSK3β are downregulated. In addition, subcutaneous implantation in nude mice shows that knockdown of Cald1 enhances the osteogenic differentiation of PDLSCs in vivo. Taken together, this study demonstrates that knockdown of Cald1 enhances the osteogenic differentiation of PDLSCs by BMP and Wnt signaling pathways, and provides a novel approach for subsequent clinical treatment.

LncRNA ADAMTS9-AS2 regulates periodontal ligament cell migration under mechanical compression via ADAMTS9/fibronectin

BACKGROUND

Periodontal ligament cells (PDLCs) are key mechanosensory cells involved in extracellular matrix (ECM) remodeling during orthodontic tooth movement (OTM). Mechanical force changes the ECM components, such as collagens and matrix metalloproteinases. However, the associations between the changes in ECM molecules and cellular dynamics during OTM remain largely uncharacterized.

OBJECTIVES

To investigate the influence of mechanical force on the morphology and migration of PDLCs and explore the interaction between ECM remodeling and cellular dynamics, including the detailed mechanisms involved.

METHODS

Human PDLCs (hPDLCs) were subjected to a static mechanical compression to mimic the compression state of OTM in vitro. A mouse OTM model was used to mimic the OTM procedure in vivo. The migration of hPDLCs was compared by wound healing and transwell migration assays. Moreover, expression levels of ADAM metallopeptidase with thrombospondin type 1 motif 9 (ADAMTS9) and fibronectin (FN) in hPDLCs were determined via western blotting, immunofluorescence staining, and enzyme-linked immunosorbent assays. Expression levels of ADAMTS9 and FN in mice were assessed via immunohistochemical staining. Additionally, the relative expression of long non-coding RNA (lncRNA) ADAMTS9-antisense RNA 2 (ADAMTS9-AS2) was assessed via quantitative real-time polymerase chain reaction. ADAMTS9-AS2 knockdown was performed to confirm its function in hPDLCs.

RESULTS

Mechanical compression induced changes in the morphology of hPDLCs. It also promoted migration and simultaneous upregulation of FN and downregulation of ADAMTS9, a fibronectinase. The mouse OTM model showed the same expression patterns of the two proteins on the compression side of the periodontium of the moved teeth. RNA sequencing revealed that lncRNA ADAMTS9-AS2 expression was significantly upregulated in hPDLCs under mechanical compression. After knocking down ADAMTS9-AS2, hPDLCs migration was significantly inhibited. ADAMTS9 expression was increased as FN expression decreased compared to that in the control group. Moreover, knockdown of ADAMTS9-AS2 reduced the effect of mechanical compression on hPDLCs migration and reversed the expression change of ADAMTS9 and FN. RNA immunoprecipitation revealed direct binding between ADAMTS9-AS2 and ADAMTS9 protein.

CONCLUSION

Our study suggests that mechanical compression induces the expression of ADAMTS9-AS2, which directly binds to ADAMTS9 and inhibits its function, leading to the promotion of downstream FN expression and ECM remodeling to facilitate hPDLCs migration and maintain the stability of the periodontium.

Emerging Role of miRNAs in the Pathogenesis of Periodontitis

MicroRNAs (miRNAs) have been found to participate in the pathogenesis of several immune-related conditions through the modulation of the expression of cytokine coding genes and other molecules that affect the activity of the immune system. Periodontitis is an example of these conditions associated with the dysregulation of several miRNAs. Several miRNAs such as let-7 family, miR-125, miR-378, miR-543, miR-302, miR-214, miR-200, miR-146, miR-142, miR-30 and miR-21 have been shown to be dysregulated in patients with periodontitis. miR-146 is the most assessed miRNA in these patients, which is up-regulated in most studies in patients with periodontitis. In the present review, we describe the impact of miRNAs dysregulation on the pathoetiology of periodontitis.

Role of non-coding RNAs in osteoporosis

Osteoporosis, a prevalent bone disorder influenced by genetic and environmental elements, significantly increases the likelihood of fractures and bone weakness, greatly affecting the lives of those afflicted. Yet, the exact epigenetic processes behind the onset of osteoporosis are still unclear. Growing research indicates that epigenetic changes could act as vital mediators that connect genetic tendencies and environmental influences, thereby increasing the risk of osteoporosis and bone fractures. Within these epigenetic factors, certain types of RNA, such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), have been recognized as key regulatory elements. These RNA types wield significant influence on gene expression through epigenetic regulation, directing various biological functions essential to bone metabolism. This extensive review compiles current research uncovering the complex ways in which miRNAs, lncRNAs, and circRNAs are involved in the development of osteoporosis, especially in osteoblasts and osteoclasts. Gaining a more profound understanding of the roles these three RNA classes play in osteoporosis could reveal new diagnostic methods and treatment approaches for this incapacitating condition. In conclusion, this review delves into the complex domain of epigenetic regulation via non-coding RNA in osteoporosis. It sheds light on the complex interactions and mechanisms involving miRNAs, lncRNAs, and circRNAs within osteoblasts and osteoclasts, offering an in-depth understanding of the less explored aspects of osteoporosis pathogenesis. These insights not only reveal the complexity of the disease but also offer significant potential for developing new diagnostic methods and targeted treatments. Therefore, this review marks a crucial step in deciphering the elusive complexities of osteoporosis, leading towards improved patient care and enhanced quality of life.

CREB1 alleviates the apoptosis and potentiates the osteogenic differentiation of zoledronic acid-treated human periodontal ligament stem cells via up-regulating VEGF

Periodontitis represents a severe inflammatory illness in tooth supporting tissue. It has been supported that cAMP response element binding protein 1 (CREB1), a common transcription factor, extensively participates in osteogenic differentiation. Here, the current study was to look into the impacts of CREB1 on the process of periodontitis and its possible action mechanism. After human periodontal ligament stem cells (PDLSCs) were challenged with zoledronic acid (ZA), CREB1 expression was examined with RT-qPCR and western blotting. CCK-8 assay appraised cell activity. Following CREB1 elevation or/and vascular endothelial growth factor (VEGF) silencing in ZA-treated PDLSCs, CCK-8 and TUNEL assays separately estimated cell viability and apoptosis. Western blotting tested the expression of apoptosis- and osteogenic differentiation-associated proteins. ALP staining measured PDLSCs osteogenic ability and ARS staining estimated mineralized nodule formation. JASPAR predicted the potential binding of CREB1 with VEGF promoter, which was then testified by ChIP and luciferase reporter assays. RT-qPCR and western blotting tested VEGF expression. CREB1 expression was declined in ZA-exposed PDLSCs and CREB1 elevation exacerbated the viability and osteogenic differentiation while obstructed the apoptosis of PDLSCs. Additionally, CREB1 bond to VEGF promoter and transcriptionally activated VEGF expression. Further, VEGF absence partially stimulated the apoptosis while suppressed the osteogenic differentiation of CREB1-overexpressing PDLSCs treated by ZA. To be concluded, CREB1 might activate VEGF transcription to obstruct the apoptosis while contribute to the osteogenic differentiation of ZA-treated PDLSCs.

The long non-coding RNA, miRNA and mRNA landscapes of cementoblasts during cementogenesis

OBJECTIVE

Stimulation of cementogenesis is essential to cementum regeneration and root restoration. Long non-coding RNAs (lncRNAs) participate in the regulatory networks of periodontal regeneration processes. We identified and analysed differentially expressed lncRNAs, miRNAs and mRNAs associated with cementogenic differentiation of cementoblasts.

MATERIALS AND METHODS

OCCM-30 immortalized mouse cementoblast cells were induced in cementogenic medium for 7 and 14 days. Total RNA was extracted and subjected to RNA sequencing to screen for differentially expressed lncRNAs, miRNAs and mRNAs. Quantitative reverse-transcription polymerase chain reaction (qRT-PCR) was performed to determine the expression levels of RNAs. Gene Ontology (GO) term and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were used to clarify the potential functions of differentially expressed genes in biological processes and pathways. lncRNA-miRNA-mRNA networks were constructed based on correlation and algorithmic analyses.

RESULTS

In all, 461 lncRNAs, 89 miRNAs and 2157 mRNAs showed differential expression in OCCM-30 cells after cementoblast differentiation. At day 7, upregulation of 248 lncRNAs, 30 miRNAs and 905 mRNAs was observed, along with downregulation of 127 lncRNAs, 34 miRNAs and 960 mRNAs. At day 14, 197 lncRNAs, 13 miRNAs and 847 mRNAs were upregulated, while 74 lncRNAs, 12 miRNAs and 760 mRNAs were downregulated. The results of qRT-PCR showed that four candidate lncRNAs, H19, Gdap10, Foxo6os and Ipw, were significantly upregulated after 7 and 14 days of cementogenic induction. The lncRNA-miRNA-mRNA network illustrated a possible competitive endogenous RNA regulatory mechanism. GO analysis showed that consistently differentially expressed mRNAs were involved in blood vessel morphogenesis, cell-substrate adhesion, cell adhesion, ossification and extracellular matrix organization. KEGG analysis indicated that extracellular matrix-receptor interaction, focal adhesion, and the PI3K-Akt, Rap1, mitogen-activated protein kinase, and Ras signalling pathways varied significantly during cementogenesis.

CONCLUSION

The expressions of lncRNA, miRNA and mRNA were significantly altered in cementoblasts after cementogenesis. This study highlighted the effect of lncRNAs in the process of cementogenesis and revealed their potential for the discovery of novel biomarkers and therapeutic targets for cementum regeneration.

Decoding the role of long non-coding RNAs in periodontitis: A comprehensive review

Periodontitis is an inflammatory disease characterized by the pathological loss of alveolar bone and the adjacent periodontal ligament. It is considered a disease that imposes a substantial health burden, with an incidence rate of 20-50%. The etiology of periodontitis is multifactorial, with genetic factors accounting for approximately half of severe cases. Studies have revealed that long non-coding RNAs (lncRNAs) play a pivotal role in periodontitis pathogenesis. Accumulating evidence suggests that lncRNAs have distinct regulatory mechanisms, enabling them to control numerous vital processes in periodontal cells, including osteogenic differentiation, inflammation, proliferation, apoptosis, and autophagy. In this review, we summarize the diverse roles of lncRNAs in the pathogenesis of periodontitis, shedding light on the underlying mechanisms of disease development. By highlighting the potential of lncRNAs as biomarkers and therapeutic targets, this review offers a new perspective on the diagnosis and treatment of periodontitis, paving the way for further investigation into the field of lncRNA-based therapeutics.

Expression and Alteration Value of Long Noncoding RNA AB073614 and FER1L4 in Patients with Acute Myeloid Leukemia (AML)

BACKGROUND

Numerous studies have probed the deregulation of the long noncoding RNA AB073614 and FER1L4, which have been discovered in a variety of cancers. However, the precise expression pattern of these lncRNAs and their clinical implications in acute myeloid leukemia (AML) remain elusive. Considering the involvement of the PI3K axis in AML pathogenesis, an investigation into the expression of AB073614 and FER1L4 targets of this pathway has been proposed, aiming to elucidate a potential mechanism underlying AML development.

METHODS

The expression levels of lncRNA AB073614 and FER1L4 were assessed in 30 newly diagnosed AML patients and 12 healthy individuals using quantitative reverse transcription-polymerase chain reaction techniques. A statistical analysis was conducted to determine the association of AB073614 and FER1L4 expression levels with clinicopathological features.

RESULTS

A significant upregulation of AB073614 was observed in AML patients compared to the control group (p < 0.05). Moreover, a notable increase in AB073614 expression levels coincided with a significant reduction in FER1L4 expression levels in AML samples (p < 0.05). The diagnostic value of these lncRNAs was validated using the receiver operating characteristic (ROC) curve and area under the curve (AUC) calculations. Sensitivity values of AB073614 and FER1L4 gene expression were 96.7% and 100%, respectively, using cut-off relative quantification of 1.045 and 0.770. Additionally, specificity values were observed to be 100%.

CONCLUSIONS

The present study indicates that AB073614 and FER1L4 might serve as prognosis biomarkers in AML patients. However, further detailed examinations in this field are warranted. It is proposed that the likely mechanism of imbalanced PI3K and PTEN activity, triggered by the deregulation of AB073614 and FER1L4, may have a crucial role in AML pathogenesis. Any component of this pathway could potentially serve as a new target for more insightful treatment approaches.

lncRNA CYTOR Facilitates Osteogenic Differentiation of Human Periodontal Ligament Stem Cells by Modulating SOX11 via Sponging miR-6512-3p

Periodontal ligament stem cells (PDLSCs) are considered ideal cell sources for the regeneration of periodontal and alveolar bone tissue. Cytoskeleton Regulator RNA (CYTOR), a newly discovered long noncoding RNA, has been reported to function as competing endogenous RNA (ceRNA) and to be involved in many biological processes. However, its roles in PDLSC osteogenic differentiation remain unclear. Here, we firstly found CYTOR was mainly sublocalized in the cytoplasm of PDLSCs and CYTOR expression was increased during osteogenic differentiation of PDLSCs. By employing gain- and loss-of-function approaches, we then identified CYTOR overexpression promoted osteogenic differentiation of PDLSCs while CYTOR knockdown inhibited this process. Furthermore, bioinformatics analysis was utilized to show that both CYTOR and SOX11 mRNA contained the same seed sites for miR-6512-3p, which was further confirmed by dual luciferase reporter assay and RNA-binding protein immunoprecipitation. Notably, CYTOR conferred its functions by directly binding to miR-6512-3p and an inverse correlation between CYTOR and miR-6512-3p on the level on SOX11 and osteogenic differentiation of PDLSCs was obtained. Additionally, miR-6512-3p could bind to SOX11 mRNA 3' UTR and repressed SOX11 expression. Moreover, level of SOX11 was significantly increased during osteogenic differentiation of PDLSCs. Knockdown of SOX11 attenuated the increasing effect of CYTOR overexpression on osteogenic differentiation of PDLSCs. Collectively, these data supported that CYTOR positively modulated the expression of SOX11 through competitively binding to miR-6512-3p, thus promoting osteogenic differentiation of PDLSCs. The CYTOR/miR-6512-3p/SOX11 axis could be a novel therapeutic target for periodontal regeneration medicine.

Redefining the architecture of ferlin proteins: Insights into multi-domain protein structure and function

Ferlins are complex, multi-domain proteins, involved in membrane trafficking, membrane repair, and exocytosis. The large size of ferlin proteins and the lack of consensus regarding domain boundaries have slowed progress in understanding molecular-level details of ferlin protein structure and function. However, in silico protein folding techniques have significantly enhanced our understanding of the complex ferlin family domain structure. We used RoseTTAFold to assemble full-length models for the six human ferlin proteins (dysferlin, myoferlin, otoferlin, Fer1L4, Fer1L5, and Fer1L6). Our full-length ferlin models were used to obtain objective domain boundaries, and these boundaries were supported by AlphaFold2 predictions. Despite the differences in amino acid sequence between the ferlin proteins, the domain ranges and distinct subdomains in the ferlin domains are remarkably consistent. Further, the RoseTTAFold/AlphaFold2 in silico boundary predictions allowed us to describe and characterize a previously unknown C2 domain, ubiquitous in all human ferlins, which we refer to as C2-FerA. At present, the ferlin domain-domain interactions implied by the full-length in silico models are predicted to have a low accuracy; however, the use of RoseTTAFold and AlphaFold2 as a domain finder has proven to be a powerful research tool for understanding ferlin structure.

Plasma Exosome miRNAs Profile in Patients With ST-Segment Elevation Myocardial Infarction

Background

Circulating microRNAs (miRNAs) have been found to have different expressions in different phases of acute myocardial infarction. The profiles of plasma exosome miRNAs in patients with ST-segment elevation myocardial infarction (STEMI) at 3–6 months postinfarction are unknown.

Objective

The aim of this study was to assess the profiles of plasma exosome miRNAs in patients with STEMI in comparison with healthy volunteers and to select specific exosome miRNAs related to pathophysiological changes post-STEMI.

Methods

Plasma and echocardiography parameters were collected from 30 patients 3–6 months after STEMI and 30 healthy volunteers. Plasma exosome miRNAs were assessed by using high-throughput sequence (Illumina HiSeq 2500) and profile of the plasma exosome miRNAs was established in 10 patients and 6 healthy volunteers. The specific exosome miRNAs related to heart diseases were selected according to the TargetScan database. The specificity of the selected exosome miRNAs was evaluated in additional 20 post-STEMI patients and 24 healthy volunteers by using quantitative PCR (qPCR). Left ventricular remodeling (LVR) was defined using the European Association of Cardiovascular Imaging criteria according to echocardiography examination. Correlations between expression of the specific miRNAs and echocardiography parameters of LVR were assessed using the Spearman correlation analysis.

Results

Twenty eight upregulated miRNAs and 49 downregulated miRNAs were found in patients 3–6 months after STEMI (p &lt; 0.01) in comparison with the healthy volunteers. The two least expressed and heart-related exosome miRNAs were hsa-miR-181a-3p (0.64-fold, p &lt; 0.01) and hsa-miR-874-3p (0.50-fold, p &lt; 0.01), which were further confirmed by using qPCR and demonstrated significant specificity in another 20 patients with post-STEMI comparing to 24 healthy volunteers [area under the curve (AUC) = 0.68, p &lt; 0.05; AUC = 0.74, p &lt; 0.05]. The expression of hsa-miR-181a-3p was downregulated in patients with LV adverse remodeling in comparison with patients without LV adverse remodeling and healthy volunteers.

Conclusion

Circulating exosome miR-874-3p and miR-181a-3p were downregulated in patients with STEMI postinfarction. Exosome hsa-miR-181a-3p might play a potential role in the development of LVR in patients with post-STEMI.

Progress in the Study of Non-Coding RNAs in Multidifferentiation Potential of Dental-Derived Mesenchymal Stem Cells

For decades, the desire for tissue regeneration has never been quenched. Dental-derived mesenchymal stem cells (DMSCs), with the potential of self-renewal and multi-directional differentiation, have attracted much attention in this topic. Growing evidence suggests that non-coding RNAs (ncRNAs) can activate various regulatory processes. Even with a slight decrease or increase in expression, ncRNAs can weaken or even subvert cellular fate. Therefore, a systematic interpretation of ncRNAs that guide the differentiation of DMSCs into cells of other tissue types is urgently needed. In this review, we introduce the roles of ncRNAs in the differentiation of DMSCs, such as osteogenic differentiation, odontogenic differentiation, neurogenic differentiation, angiogenic differentiation and myogenic differentiation. Additionally, we illustrate the regulatory mechanisms of ncRNAs in the differentiation of DMSCs, such as epigenetic regulation, transcriptional regulation, mRNA modulation, miRNA sponges and signalling. Finally, we summarize the types and mechanisms of ncRNAs in the differentiation of DMSCs, such as let-7 family, miR-17∼92 family, miR-21, lncRNA H19, lncRNA ANCR, lncRNA MEG3, circRNA CDR1as and CircRNA SIPA1L1. If revealing the intricate relationship between ncRNAs and pluripotency of DMSCs 1 day, the application of DMSCs in regenerative medicine and tissue engineering will be improved. Our work could be an important stepping stone towards this future.

Emerging role of epigenetic regulations in periodontitis: a literature review

Periodontitis is mainly initiated by periodontal pathogens including Porphyromonas gingivalis, and bad living habits such as smoking aggravate its incidence and severity. The development of periodontitis is closely related to the host's immune responses and the secretion of various cytokine networks. Moreover, periodontitis has an important connection with the development of systemic diseases. Recently, epigenetics which is a fast-developing hot research area has provided new insights into the research of various diseases including periodontitis. Epigenetics is an important supplement to the regulation of gene expression. The study of epigenetics is about causing heritable gene expression or cell phenotype changes through certain mechanisms without changing the DNA sequence. It mainly includes histone modification, DNA methylation, non-coding RNA and the latest research hotspot m6A RNA methylation. In the review, we comprehensively summarize the latest literature on the potential epigenetic regulations in various aspects of periodontitis.

LncRNA FER1L4 promotes differentiation and inhibits proliferation of NSCs via miR-874-3p/Ascl2

Neural stem cells (NSCs) may offer beneficeial and promising adjuncts for treatment of neurological diseases such as Alzheimer's disease (AD), Parkinson's disease (PD) and spinal cord injuries. Previous studies showed that LncRNA FER1L4 plays crucial roles in many biological procedures such as invasion, metabolism, apoptosis, and stem cell differentiation. However, the role of FER1L4 in differentiation and growth of NSCs remains unknown. In the present research, we noted that FER1L4 is upregulated in NSCs induced with TNFα. Ectopic expression of FER1L4 suppresses NSCs proliferation and induces NSCs differentiated into neurons and astrocytes. Using Starbase online software, we identified that FER1L4 is one potential target gene of miR-874-3p. Ectopic expression of FER1L4 decreases miR-874-3p expression in NSCs. We identified Ascl2 is one target gene for miR-874-3p. Overexpression of FER1L4 enhances Ascl2 expression in NSCs. Furthermore, we proved that FER1L4 modulates the proliferation and differentiation of NSCs via regulating Ascl2.

miR-874: An Important Regulator in Human Diseases

miR-874 is located at 5q31.2, which is frequently deleted in cancer. miR-874 is downregulated in 22 types of cancers and aberrantly expressed in 18 types of non-cancer diseases. The dysfunction of miR-874 is not only closely related to the diagnosis and prognosis of tumor patients but also plays an important role in the efficacy of tumor chemotherapy drugs. miR-874 participates in the ceRNA network of long non-coding RNAs or circular RNAs, which is closely related to the occurrence and development of cancer and other non-cancer diseases. In addition, miR-874 is also involved in the regulation of multiple signaling pathways, including the Wnt/β-catenin signaling pathway, Hippo signaling pathway, PI3K/AKT signaling pathway, JAK/STAT signaling pathway, and Hedgehog signaling pathway. This review summarizes the molecular functions of miR-874 in the biological processes of tumor cell survival, apoptosis, differentiation, and tumorigenesis, and reveal the value of miR-874 as a cancer biomarker in tumor diagnosis and prognosis. Future work is necessary to explore the potential clinical application of miR-874 in chemotherapy resistance.

Long non-coding RNA SNHG5 promotes the osteogenic differentiation of bone marrow mesenchymal stem cells via the miR-212-3p/GDF5/SMAD pathway

Background

The treatment of bone loss has posed a challenge to clinicians for decades. Thus, it is of great significance to identify more effective methods for bone regeneration. However, the role and mechanisms of long non-coding RNA small nucleolar RNA host gene 5 (SNHG5) during osteogenic differentiation remain unclear.

Methods

We investigated the function of SNHG5, Yin Yang 1 (YY1), miR-212-3p and growth differentiation factor 5 (GDF5) in osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs) in vitro and in vivo. Molecular mechanisms were clarified by chromatin immunoprecipitation assay and dual luciferase reporter assay.

Results

We found SNHG5 expression was upregulated during osteogenesis of hBMSCs. Knockdown of SNHG5 in hBMSCs inhibited osteogenic differentiation while overexpression of SNHG5 promoted osteogenesis. Moreover, YY1 transcription factor directly bound to the promoter region of SNHG5 and regulated SNHG5 expression to promote osteogenesis. Dual luciferase reporter assay confirmed that SNHG5 acted as a miR-212-3p sponge and miR-212-3p directly targeted GDF5 and further activated Smad1/5/8 phosphorylation. miR-212-3p inhibited osteogenic differentiation, while GDF5 promoted osteogenic differentiation of hBMSCs. In addition, calvarial defect experiments showed knockdown of SNHG5 and GDF5 inhibited new bone formation in vivo.

Conclusion

Our results demonstrated that the novel pathway YY1/SNHG5/miR-212-3p/GDF5/Smad regulates osteogenic differentiation of hBMSCs and may serve as a potential target for the treatment of bone loss.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02781-8.

FER1L4：A long non-coding RNA with multiple roles in the occurrence and development of tumors

BACKGROUND

FER-1 family member 4 (FER1L4), a 6.7 kb lncRNA located at 20q11.22, plays an important biological function in a variety of tumor diseases. The purpose of this review is to clarify the pathophysiological mechanism and potential biological function of FER1L4 in different tumors.

METHODS

By searching the relevant literature of PubMed, the specific pathophysiological mechanism of FER1L4 in different tumors was summarized.

RESULTS

LncRNA FER1L4 is one of the key factors in tumorigenesis and is abnormally down-regulated in many tumors, including osteosarcoma, lung cancer, laryngeal squamous cell carcinoma, laryngeal cancer, colorectal cancer, ovarian cancer, prostate cancer, esophageal cancer, gastric cancer, endometrial cancer, osteoarthritis, rheumatoid arthritis and so on. However, FER1L4 is downregulated in breast cancer, glioma, oral squamous cell carcinoma, renal clear cell carcinoma and periodontitis, and plays a protective role in orthodontic teeth. In addition, as a tumor suppressor gene or oncogene, FER1L4 affects tumor proliferation, invasion, migration and apoptosis. Conclusion：LncRNA FER1L4 has a good application prospect in the treatment and diagnosis of many kinds of tumors.

The Roles of Noncoding RNAs in the Development of Osteosarcoma Stem Cells and Potential Therapeutic Targets

Osteosarcoma (OS) is the common bone tumor in children and adolescents. Because of chemotherapy resistance, the OS patients have a poor prognosis. The one reason of chemotherapeutic resistance is the development of cancer stem cells (CSCs). CSCs represent a small portion of tumor cells with the capacity of self-renewal and multipotency, which are associated with tumor initiation, metastasis, recurrence and drug resistance. Recently, noncoding RNAs (ncRNAs) have been reported to critically regulate CSCs. Therefore, in this review article, we described the role of ncRNAs, especially miRNAs, lncRNAs and circRNAs, in regulating CSCs development and potential mechanisms. Specifically, we discussed the role of multiple miRNAs in targeting CSCs, including miR-26a, miR-29b, miR-34a, miR-133a, miR-143, miR-335, miR-382, miR-499a, miR-1247, and let-7days. Moreover, we highlighted the functions of lncRNAs in regulating CSCs in OS, such as B4GALT1-AS1, DANCR, DLX6-AS1, FER1L4, HIF2PUT, LINK-A, MALAT1, SOX2-OT, and THOR. Due to the critical roles of ncRNAs in regulation of OS CSCs, targeting ncRNAs might be a novel strategy for eliminating CSCs for OS therapy.

The Expression and Regulatory Roles of Long Non-Coding RNAs in Periodontal Ligament Cells: A Systematic Review

Periodontal ligament (PDL) cells play a pivotal role in periodontal and bone homeostasis and have promising potential for regenerative medicine and tissue engineering. There is compelling evidence that long non-coding RNAs (lncRNAs) are differentially expressed in PDL cells compared to other cell types and that these lncRNAs are involved in a variety of biological processes. This study systematically reviews the current evidence regarding the expression and regulatory functions of lncRNAs in PDL cells during various biological processes. A systematic search was conducted on PubMed, the Web of Science, Embase, and Google Scholar to include articles published up to 1 July 2021. Original research articles that investigated the expression or regulation of lncRNAs in PDL cells were selected and evaluated for a systematic review. Fifty studies were ultimately included, based on our eligibility criteria. Thirteen of these studies broadly explored the expression profiles of lncRNAs in PDL cells using microarray or RNA sequencing. Nineteen studies investigated the mechanisms by which lncRNAs regulate osteogenic differentiation in PDL cells. The remaining 18 studies investigated the mechanism by which lncRNAs regulate the responses of PDL cells to various stimuli, namely, lipopolysaccharide-induced inflammation, tumor necrosis factor alpha-induced inflammation, mechanical stress, oxidative stress, or hypoxia. We systematically reviewed studies on the expression and regulatory roles of lncRNAs in diverse biological processes in PDL cells, including osteogenic differentiation and cellular responses to inflammation, mechanical stress, and other stimuli. These results provide new insights that may guide the development of lncRNA-based therapeutics for periodontal and bone regeneration.

p73-regulated FER1L4 lncRNA sponges the oncogenic potential of miR-1273g-3p and aids in the suppression of colorectal cancer metastasis

p73 belongs to the p53 tumor suppressor family and is involved in the suppression of metastasis. However, its specific mechanism of action remains to be elucidated. Long non-coding RNAs portray a crucial role in tumor suppression. We have identified lncRNA FER1L4 as a p73 transcriptional target. The binding of p73 to FER1L4 promoter was established by bioinformatics analysis, luciferase reporter, and ChIP assays. Both FER1L4 and p73 knockdown enhanced the migration and invasion rate of colorectal cancer cells. FER1L4 also plays a critical role in p73-mediated cell-cycle arrest and apoptosis. FER1L4 sponged the expression of miR-1273g-3p, which, in turn, increased PTEN expression, leading to cell-cycle arrest. RNA in situ hybridization revealed the down-regulation of both p73 and FER1L4 expression in a metastatic colon cancer tissue as compared with non-metastatic tissue. Collectively, we impart conclusive proof that p73 exerts its anti-metastatic properties by inducing lncRNA FER1L4 in response to genotoxic stress.

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Long non-coding RNA FER1L4 functions as a direct transcriptional target of p73

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FER1L4 plays a pivotal role in p73-mediated cell-cycle arrest and apoptosis

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FER1L4kd augments colorectal cancer cell proliferation in a p73-dependent manner

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p73-FER1L4 axis sponges miR-1273g-3p and inhibits its oncogenic role

Dicer Enhances Bevacizumab-Related Inhibition of Hepatocellular Carcinoma via Blocking the Vascular Endothelial Growth Factor Pathway

Purpose

Vascular endothelial growth factor (VEGF) family members contribute greatly to the development and angiogenesis of hypervascular hepatocellular carcinoma (HCC). We have previously shown that Dicer inhibited HCC growth. In this study, we aimed to determine the relationship between Dicer and VEGF in HCC.

Methods

Gain-of-function studies were performed to determine the effect of different treatments on the proliferation, migration, and invasion of HCC cells. Expression of VEGF-A in xenograft tumor tissues was analysed using Western blotting, and that of CD31 using immunohistochemical analysis.

Results

We found that Dicer inhibited proliferation, migration and invasion of HCC cells by suppressing VEGF-A expression. Interestingly, VEGF-A165, which is the most prominent VEGF-A isoform, counteracted Dicer-induced inhibition of HCC cells. In addition, a monoclonal anti-VEGF antibody (bevacizumab) enhanced Dicer-induced inhibition of HCC in vitro and in vivo. Further, immunohistochemical analysis of CD31 indicated bevacizumab and Dicer synergized to reduce tumor microvessel density.

Conclusion

Our data demonstrated that Dicer enhanced bevacizumab-related inhibition of HCC cell via the VEGF pathway; therefore, Dicer in coordination with bevacizumab may provide another potential approach for HCC therapy.

Comprehensive analysis of the long noncoding RNA-associated competitive endogenous RNA network in the osteogenic differentiation of periodontal ligament stem cells

BACKGROUD

The mechanism implicated in the osteogenesis of human periodontal ligament stem cells (PDLSCs) has been investigated for years. Previous genomics data analyses showed that long noncoding RNA (lncRNA), microRNA (miRNA) and messenger RNA (mRNA) have significant expression differences between induced and control human PDLSCs. Competing for endogenous RNAs (ceRNA), as a widely studied mechanism in regenerative medicine, while rarely reported in periodontal regeneration. The key lncRNAs and their ceRNA network might provide new insights into molecular therapies of periodontal regeneration based on PDLSCs.

RESULTS

Two networks reflecting the relationships among differentially expressed RNAs were constructed. One ceRNA network was composed of 6 upregulated lncRNAs, 280 upregulated mRNAs, and 18 downregulated miRNAs. The other network contained 33 downregulated lncRNAs, 73 downregulated mRNAs, and 5 upregulated miRNAs. Functional analysis revealed that 38 GO terms and 8 pathways related with osteogenesis were enriched. Twenty-four osteogenesis-related gene-centred lncRNA-associated ceRNA networks were successfully constructed. Among these pathways, we highlighted MAPK and TGF-beta pathways that are closely related to osteogenesis. Subsequently, subnetworks potentially linking the GO:0001649 (osteoblast differentiation), MAPK and TGF-beta pathways were constructed. The qRT-PCR validation results were consistent with the microarray analysis.

CONCLUSION

We construct a comprehensively identified lncRNA-associated ceRNA network might be involved in the osteogenesis of PDLSCs, which could provide insights into the regulatory mechanisms and treatment targets of periodontal regeneration.

MicroRNA Hsa-Let-7b Regulates the Osteogenic Differentiation of Human Periodontal Ligament Stem Cells by Targeting CTHRC1

Let-7 miRNA family has been proved as a key regulator of mesenchymal stem cells' (MSCs') biological features. However, whether let-7b could affect the differentiation or proliferation of periodontal ligament stem cells (PDLSCs) is still unknown. Here, we found that the expression of hsa-let-7b was visibly downregulated after mineralization induction of PDLSCs. After transfected with hsa-let-7b mimics or inhibitor reagent, the proliferation ability of PDLSCs was detected by cell counting kit-8 (CCK-8), flow cytometry, and 5-ethynyl-2-deoxyuridine (EdU) assay. On the other hand, the osteogenic differentiation capacity was detected by alkaline phosphatase (ALP) staining and activity, alizarin red staining, Western blot, and quantitative real-time reverse-transcription polymerase chain reaction (qRT-PCR). We verified that hsa-let-7b did not significantly impact the proliferation ability of PDLSCs, but it could curb the osteogenic differentiation of PDLSCs. Besides, we predicted CTHRC1 acts as the downstream gene of hsa-let-7b to affect this process. Moreover, the combination of CTHRC1 and hsa-let-7b was verified by dual luciferase reporter assay. Our results demonstrated that the osteogenic differentiation of PDLSCs was enhanced after inhibiting hsa-let-7b, while was weakened after cotransfection with Si-CTHRC1. Collectively, hsa-let-7b can repress the osteogenic differentiation of PDLSCs by regulating CTHRC1.

EZH2 Regulates Lipopolysaccharide-Induced Periodontal Ligament Stem Cell Proliferation and Osteogenesis through TLR4/MyD88/NF-κB Pathway

Background

Periodontitis induced by bacteria especially Gram-negative bacteria is the most prevalent chronic inflammatory disease worldwide. Emerging evidence supported that EZH2 plays a significant role in the inflammatory response of periodontal tissues. However, little information is available regarding the underlying mechanism of EZH2 in periodontitis. This study is aimed at determining the potential role and underlying mechanism of EZH2 in periodontitis.

Methods

The protein levels of EZH2, H3K27ME, p-p65, p-IKB, TLR4, MyD88, Runx2, and OCN were examined by western blot assay. Proliferation was evaluated by CCK8 assay. The levels of TNFα, IL1β, and IL6 were detected by ELISA assay. Migration was detected by wound healing assay. The distribution of p65 was detected by immunofluorescence. The formation of mineralized nodules was analyzed using alizarin red staining.

Results

LPS stimulation significantly promoted EZH2 and H3K27me3 expression in primary human periodontal ligament stem cells (PDLSCs). Targeting EZH2 prevented LPS-induced upregulation of the inflammatory cytokines and inhibition of cell proliferation and migration. Furthermore, EZH2 knockdown attenuated the TLR4/MyD88/NF-κB signaling to facilitate PDLSC osteogenesis.

Conclusions

Modulation of the NF-κB pathway through the inhibition of EZH2 may offer a new perspective on the treatment of chronic apical periodontitis.

MicroRNA miR-874-3p inhibits osteoporosis by targeting leptin (LEP)

MicroRNAs (miRNAs) regulate osteogenic differentiation and influence osteoporosis (OP). The aim of this study was to determine the potential role of miR-874-3p in OP. The expression levels of miR-874-3p and leptin (LEP) in the femoral neck trabeculae of 35 patients with or without OP were measured by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The effects of miR-874-3p or LEP on the cell proliferation and alkaline phosphatase (ALP), runt-related transcription factor 2 (RUNX2), osteocalcin (OCN), and osterix (OSX) levels were observed by upregulating miR-874-3p in human bone marrow mesenchymal stem cells (hBMSCs). Additionally, calcium deposition levels were evaluated using alizarin red staining (ARS). Molecular mechanisms of miR-874-3p and LEP underlying the osteogenic differentiation of hBMSCs were also evaluated using bioinformatics analysis, luciferase reporter assays, and RNA pull-down assays. The miR-874-3p levels were significantly lower in the femoral neck trabeculae of patients with OP than those of the control group, while the opposite was observed regarding the levels of LEP. Expression levels of miR-874-3p in hBMSCs were upregulated during osteogenic differentiation, while those of LEP were downregulated. Moreover, miR-874-3p upregulation promoted ALP, RUNX2, OCN, and OSX mRNA expression, cell proliferation, and calcium deposition in hBMSCs. LEP was found to be a target gene of miR-874-3p. Overexpression of LEP inhibited the expression of osteoblast markers and reversed the effect of osteogenic differentiation induced by the upregulation of miR-874-3p. In conclusion, miR-874-3p promoted the proliferation and differentiation of hBMSCs by downregulating the expression of LEP, thus inhibiting OP.

Abbreviations : miRNAs: microRNAs; OP: osteoporosis; hBMSCs: human Bone Marrow Mesenchymal stem cells; LEP: leptin; DEGs: differentially expressed genes

Global miRNA expression of bone marrow mesenchymal stem/stromal cells derived from Fanconi anemia patients

Fanconi anemia (FA) is a rare genetic disorder characterized by genomic instability, developmental defects, and bone marrow (BM) failure. Hematopoietic stem cells (HSCs) in BM interact with the mesenchymal stem/stromal cells (MSCs); and this partly sustains the tissue homeostasis. MicroRNAs (miRNAs) can play a critical role during these interactions possibly via paracrine mechanisms. This is the first study addressing the miRNA profile of FA BM-MSCs obtained before and after BM transplantation (preBMT and postBMT, respectively). Non-coding RNA expression profiling and quality control analyses were performed in Donors (n = 13), FA preBMT (n = 11), and FA postBMT (n = 6) BM-MSCs using GeneChip miRNA 2.0 Array. Six Donor-FA preBMT pairs were used to identify a differentially expressed miRNA expression signature containing 50 miRNAs, which exhibited a strong correlation with the signature obtained from unpaired samples. Five miRNAs (hsa-miR-146a-5p, hsa-miR-148b-3p, hsa-miR-187-3p, hsa-miR-196b-5p, and hsa-miR-25-3p) significantly downregulated in both the paired and unpaired analyses were used to generate the BM-MSCs' miRNA-BM mononuclear mRNA networks upon integration of a public dataset (GSE16334; studying Donor versus FA samples). Functionally enriched KEGG pathways included cellular senescence, miRNAs, and pathways in cancer. Here, we showed that hsa-miR-146a-5p and hsa-miR-874-3p were rescued upon BMT (n = 3 triplets). The decrease in miR-146a-5p was also validated using RT-qPCR and emerged as a strong candidate as a modulator of BM mRNAs in FA patients.

LncPVT1 regulates osteogenic differentiation of human periodontal ligament cells via miR-10a-5p/brain-derived neurotrophic factor

BACKGROUND

Identifying the factors affecting osteoblast differentiation ofperiodontal ligamentcells (PDLCs) can help enhance the regeneration of periodontal tissue.LncRNAplasmacytoma variant translocation 1 (lncPVT1) is an important regulatory factor involved in many biological processes, but its role in osteogenesisremains unclear.

METHODS

Expressionsof osteogenic markers were detected by quantitative reverse transcription polymerase chain reaction and Western blot analysis. Alkaline phosphatase staining was conducted for early osteoblast differentiation and alizarin red S staining was used for mineral deposition. RNA sequencing was used to identify the miRNAs regulated by lncPVT1 during osteogenesis. Cell transfection was used to overexpress or knockdown lncPVT1 and miR-10a-5p. Dual luciferase reporter assayswere conducted to analyze the binding of miR-10a-5p to brain-derived neurotrophic factor (BDNF).

RESULTS

LncPVT1 was significantly increased during osteogenic induction of PDLCs. Overexpression of lncPVT1 promoted osteogenesis, whereas lncPVT1 knockdown inhibited this process. RNA sequencing showed that miR-10a-5p expression was significantly increased after lncPVT1 knockdown.RNA immunoprecipitation assay further demonstrated the binding potential of lncPVT1 and miR-10a-5p. MiR-10a-5p inhibited the osteogenesis of PDLCs, and partially reversed the stimulatory effects of lncPVT1.Subsequently, we identified a predicted binding site for miR-10a-5p on BDNF and confirmed it using dual luciferase reporter assays. Moreover, lncPVT1 upregulated the expression of BDNF, while miR-10a-5p downregulated BDNF expression. BDNF promoted osteogenesis and partially rescued the si-lncPVT1-mediated inhibition of PDLCs osteogenic differentiation.

CONCLUSION

LncPVT1 positively regulated the osteogenic differentiation of PDLCs via miR-10a-5p and BDNF.Our resultsprovide a promising target for enhancing the osteogenic potential of PDLCs. This article is protected by copyright. All rights reserved.

The regulation mechanism of LINC00707 on the osteogenic differentiation of human periodontal ligament stem cells

The osteogenic differentiation of periodontal ligament stem cells (PDLSCs) is important for periodontal tissue repair and regeneration. Long non-coding RNAs (lncRNAs) are key regulators of diverse biological processes. However, their roles in PDLSC osteogenic differentiation are still largely unknown. This study explored the effect of LINC00707 and its mechanism on the osteogenic differentiation of human PDLSCs. Results showed an increase in LINC00707 and forkhead box O1 (FOXO1) but a decrease in miR-490-3p during PDLSC osteogenic differentiation. LINC00707 and FOXO1 promoted osteogenic differentiation as evidenced by the formation of calcium nodules and the increase in osteogenic markers such as alkaline phosphatase, osteocalcin (OCN), and runt-related transcription factor 2 (Runx2). LINC00707 and FOXO1 knockdown exhibited opposite effects. Dual-luciferase reporter assay and qRT-PCR showed that LINC00707 can specially bind to miR-490-3p, which reversed the effect of LINC00707 on PDLSCs. MiR-490-3p inhibitor relieved the inhibiting effect of sh-LINC00707 on osteogenic differentiation. Further investigation revealed that LINC00707 can promote osteogenic differentiation by regulating FOXO1 expression through miR-490-3p sponging. Thus, the LINC00707/miR-490-3p/FOXO1 axis modulated PDLSC osteogenic differentiation and might be a promising therapeutic target for periodontal diseases.

MiR-874-3p inhibits osteogenic differentiation of human periodontal ligament fibroblasts through regulating Wnt/β-catenin pathway

Background/purpose

Previous studies have shown that miR-874 is considered to be an important regulatory factor that participated in osteoclast differentiation. The role of miR-874-3p on osteoclast differentiation of human periodontal ligament fibroblast(hPDLF), however, is still unclear. This study was aimed to delve into the related molecular mechanism of miR-874-3p on hPDLF osteoclast differentiation.

Materials and methods

The qRT-PCR assays were applied to check miR-874-3p and WNT3A expression levels during the osteoclast differentiation of hPDLF. Alkaline phosphatase (ALP) activity assays and alizarin red staining assays were applied to appraise the degree of hPDLF osteoclast differentiation. Bioinformatics method and dual-luciferase reporter assay were employed together to anticipate and certify the interaction between miR-874-3p and WNT3A. Western blot assay was applied to examine the β-catenin and WNT3A expression in transfected hPDLF.

Results

In this study, the results indicated that the expression level of miR-874-3p was gradually down-regulated while WNT3A was concomitantly increased during osteogenic differentiation of hPDLF. Overexpression or knockdown of miR-874-3p would inhibit or promote WNT3A and β-catenin protein expression as well as osteogenic differentiation of hPDLF, respectively. Further research indicated that miR-874-3p directly regulated WNT3A expression via coupling with the 3′-UTR of WNT3A. Finally, upregulation of WNT3A expression levels rescues β-catenin expression levels and osteogenic differentiation of hPDLF inhibited by miR-874-3p was explored.

Conclusion

MiR-874-3p inhibits osteogenic differentiation of hPDLF through regulating Wnt/β-catenin pathway.

Maxillofacial-Derived Mesenchymal Stem Cells: Characteristics and Progress in Tissue Regeneration

Maxillofacial-derived mesenchymal stem cells (MFSCs) are a particular collective type of mesenchymal stem cells (MSCs) that originate from the hard and soft tissue of the maxillofacial region. Recently, many types of MFSCs have been isolated and characterized. MFSCs have the common characteristics of being extremely accessible and amazingly multipotent and thus have become a promising stem cell resource in tissue regeneration. However, different MFSCs can give rise to different cell lineages, have different advantages in clinical use, and regulate the immune and inflammation microenvironment through paracrine mechanisms in different ways. Hence, in this review, we will concentrate on the updated new findings of all types of MFSCs in tissue regeneration and also introduce the recently discovered types of MFSCs. Important issues about proliferation and differentiation in vitro and in vivo, up-to-date clinical application, and paracrine effect of MFSCs in tissue regeneration will also be discussed. Our review may provide a better guide for the clinical use of MFSCs and further direction of research in MFSC regeneration medicine.

ILK regulates osteogenic differentiation of Human Periodontal Ligament Stem Cells through YAP-mediated Mechanical Memory

Mechanical memory meant the mechanical properties of the matrix could influence the cell fate even after the matrix was changed and has been justified in many kinds of cells. To utilize the phenomenon to improve periodontal tissue engineering, we studied whether mechanical memory existed in human periodontal ligament stem cells and testified if ILK plays a role in this process. The substrate of different stiffness was fabricated by gelatin methacrylate hydrogel. Two groups of hPDLSCs with stiff (St) and soft (So) matrix respectively were cultivated. Then half of the cells exchanged their matrix stiffness in the fourth passage and therefore So, St, So-St and St-So were formed. Morphology of hPDLSCs and intracellular location of YAP was observed via fluorescence staining, osteogenic differentiation of hPDLSCs was assessed by Real-Time PCR, ALP staining and western blot. Then all these were reassessed after the ILK gene had been knocked down. The results showed that morphology and YAP location of hPDLSCs were different between matrix changed and unchanged groups; osteogenic genes expression, ALP staining and western blot also varied. After the ILK gene had been knocked down, the YAP location and osteogenic activity of hPDLSCs were significantly influenced. Thus, it could be concluded that mechanical memory exists in hPDLSCs; ILK is involved in this process.

Long non-coding RNAs: Emerging roles in periodontitis

Periodontitis is a major burden of public health, affecting 20%-50% of the global population. It is a complex inflammatory disease characterized by the destruction of supporting structures of the teeth, leading to tooth loss and the emergence or worsening of systematic diseases. Understanding the molecular mechanisms underlying the physiopathology of periodontitis is beneficial for targeted therapeutics. Long non-coding RNAs (lncRNAs), transcripts made up of more than 200 nucleotides, have emerged as novel regulators of many biological and pathological processes. Recently, an increasing number of dysregulated lncRNAs have been found to be implicated in periodontitis. In this review, an overview of lncRNAs, including their biogenesis, characteristics, function mechanisms and research approaches, is provided. And we summarize recent research reports on the emerging roles of lncRNAs in regulating proliferation, apoptosis, inflammatory responses, and osteogenesis of periodontal cells to elucidate lncRNAs related physiopathology of periodontitis. Furthermore, we have highlighted the underlying mechanisms of lncRNAs in periodontitis pathology by interacting with microRNAs. Finally, the potential clinical applications, current challenges, and prospects of lncRNAs as diagnostic and prognostic biomarkers and therapeutic targets for periodontitis disease are discussed.

lncRNA FER1L4 is dysregulated in osteoarthritis and regulates IL-6 expression in human chondrocyte cells

Osteoarthritis (OA) is the most prevalent joint disease and is one of the major causes of disability in the world. There has been an increase in the incidence of OA, which is associated with an aging population, sedentary lifestyle, and reduced physical activity. Due to the complex OA pathogenesis, there are limited diagnostic tools. OA is a degenerative joint disorder with a recognized inflammatory component, usually described as abnormal expression of inflammatory factors. For instance, interleukin 6 (IL‐6) has been shown to be upregulated in serum and synovial fluid among patients with OA. Most of the inflammatory factors have been associated with the expression of long noncoding RNAs (lncRNAs). However, the role of the novel lncRNA Fer-1-like protein 4 (FER1L4) in OA is yet to be determined. Here, we interrogated the expression profile of FER1L4 in patients with OA to define its potential application as a diagnostic marker. We collected synovial fluid and blood samples from both OA cases and normal controls. Using qRT-PCR, we evaluated the expression of FER1L4 in plasma and synovial fluid. On the other hand, the expression of IL-6 in plasma and synovial fluid was assessed using ELISA. Besides, the effect of age, gender or disease stage in the expression of the FER1L4 in plasma was also estimated. Moreover, the receiver operating characteristic (ROC) curves were used to determine the impact of FER1L4 in OA cases compared with the normal controls. In addition, we analyzed the correlation between FER1L4 and IL-6 through Pearson correlation analysis. Also, IL-6 expression in overexpressed FER1L4 samples was detected in chondrocytes through western blot analysis, while FER1L4 expression following endogenous IL-6 exposure was detected by qRT-PCR. Our data showed that whereas lncRNA FER1L4 is downregulated in OA patients, IL‐6 is upregulated. The plasma FER1L4 levels among the OA cases were suppressed with disease progression and old age, and the down-regulation could efficiently discriminate OA patients from normal subjects. In addition, upregulation of FER1L4 inhibited IL‐6 expression in human chondrocyte cells, and treatment with different concentrations of exogenous IL‐6 did not affect the expression of FER1L4. Taken together, our data demonstrates that FER1L4 could efficiently identify OA cases from normal subjects, and can also modulate the expression of IL‐6 in human chondrocytes.

MicroRNAs: Harbingers and shapers of periodontal inflammation

Periodontal disease is an inflammatory reaction of the periodontal tissues to oral pathogens. In the present review we discuss the intricate effects of a regulatory network of gene expression modulators, microRNAs (miRNAs), as they affect periodontal morphology, function and gene expression during periodontal disease. These miRNAs are small RNAs involved in RNA silencing and post-transcriptional regulation and affect all stages of periodontal disease, from the earliest signs of gingivitis to the regulation of periodontal homeostasis and immunity and to the involvement in periodontal tissue destruction. MiRNAs coordinate periodontal disease progression not only directly but also through long non-coding RNAs (lncRNAs), which have been demonstrated to act as endogenous sponges or decoys that regulate the expression and function of miRNAs, and which in turn suppress the targeting of mRNAs involved in the inflammatory response, cell proliferation, migration and differentiation. While the integrity of miRNA function is essential for periodontal health and immunity, miRNA sequence variations (genetic polymorphisms) contribute toward an enhanced risk for periodontal disease progression and severity. Several polymorphisms in miRNA genes have been linked to an increased risk of periodontitis, and among those, miR-146a, miR-196, and miR-499 polymorphisms have been identified as risk factors for periodontal disease. The role of miRNAs in periodontal disease progression is not limited to the host tissues but also extends to the viruses that reside in periodontal lesions, such as herpesviruses (human herpesvirus, HHV). In advanced periodontal lesions, HHV infections result in the release of cytokines from periodontal tissues and impair antibacterial immune mechanisms that promote bacterial overgrowth. In turn, controlling the exacerbation of periodontal disease by minimizing the effect of periodontal HHV in periodontal lesions may provide novel avenues for therapeutic intervention. In summary, this review highlights multiple levels of miRNA-mediated control of periodontal disease progression, (i) through their role in periodontal inflammation and the dysregulation of homeostasis, (ii) as a regulatory target of lncRNAs, (iii) by contributing toward periodontal disease susceptibility through miRNA polymorphism, and (iv) as periodontal microflora modulators via viral miRNAs.

Multidifferentiation potential of dental-derived stem cells

Tooth-related diseases and tooth loss are widespread and are a major public health issue. The loss of teeth can affect chewing, speech, appearance and even psychology. Therefore, the science of tooth regeneration has emerged, and attention has focused on tooth regeneration based on the principles of tooth development and stem cells combined with tissue engineering technology. As undifferentiated stem cells in normal tooth tissues, dental mesenchymal stem cells (DMSCs), which are a desirable source of autologous stem cells, play a significant role in tooth regeneration. Researchers hope to reconstruct the complete tooth tissues with normal functions and vascularization by utilizing the odontogenic differentiation potential of DMSCs. Moreover, DMSCs also have the ability to differentiate towards cells of other tissue types due to their multipotency. This review focuses on the multipotential capacity of DMSCs to differentiate into various tissues, such as bone, cartilage, tendon, vessels, neural tissues, muscle-like tissues, hepatic-like tissues, eye tissues and glands and the influence of various regulatory factors, such as non-coding RNAs, signaling pathways, inflammation, aging and exosomes, on the odontogenic/osteogenic differentiation of DMSCs in tooth regeneration. The application of DMSCs in regenerative medicine and tissue engineering will be improved if the differentiation characteristics of DMSCs can be fully utilized, and the factors that regulate their differentiation can be well controlled.

Analyses of key mRNAs and lncRNAs for different osteo-differentiation potentials of periodontal ligament stem cell and gingival mesenchymal stem cell

Both human periodontal ligament stem cells (hPDLSCs) and human gingival mesenchymal stem cells (hGMSCs) are candidate seed cells for bone tissue engineering, but the osteo-differentiation ability of the latter is weaker than the former, and the mechanisms are unknown. To explore the potential regulation of mRNAs and long non-coding RNAs (lncRNAs), this study obtained the gene expression profiles of hPDLSCs and hGMSCs in both undifferentiated and osteo-differentiated conditions by microarray assay and then analysed the common and specific differentially expressed mRNAs and lncRNAs in hPDLSCs and hGMSCs through bioinformatics method. The results showed that 275 mRNAs and 126 lncRNAs displayed similar changing patterns in hPDLSCs and hGMSCs after osteogenic induction, which may regulate the osteo-differentiation in both types of cells. In addition, the expression of 223 mRNAs and 238 lncRNAs altered only in hPDLSCs after osteogenic induction, and 177 mRNAs and 170 lncRNAs changed only in hGMSCs. These cell-specific differentially expressed mRNAs and lncRNAs could underlie the different osteo-differentiation potentials of hPDLSCs and hGMSCs. Finally, dickkopf Wnt signalling pathway inhibitor 1 (DKK1) was proved to be one regulator for the weaker osteo-differentiation ability of hGMSCs through validation experiments. We hope these results help to reveal new mRNAs-lncRNAs-based molecular mechanism for osteo-differentiation of hPDLSCs and hGMSCs and provide clues on strategies for improving stem cell-mediated bone regeneration.

Long Non-coding RNAs and MicroRNAs Interplay in Osteogenic Differentiation of Mesenchymal Stem Cells

Long non-coding RNAs (lncRNAs) have gained great attention as epigenetic regulators of gene expression in many tissues. Increasing evidence indicates that lncRNAs, together with microRNAs (miRNAs), play a pivotal role in osteogenesis. While miRNA action mechanism relies mainly on miRNA-mRNA interaction, resulting in suppressed expression, lncRNAs affect mRNA functionality through different activities, including interaction with miRNAs. Recent advances in RNA sequencing technology have improved knowledge into the molecular pathways regulated by the interaction of lncRNAs and miRNAs. This review reports on the recent knowledge of lncRNAs and miRNAs roles as key regulators of osteogenic differentiation. Specifically, we described herein the recent discoveries on lncRNA-miRNA crosstalk during the osteogenic differentiation of mesenchymal stem cells (MSCs) derived from bone marrow (BM), as well as from different other anatomical regions. The deep understanding of the connection between miRNAs and lncRNAs during the osteogenic differentiation will strongly improve knowledge into the molecular mechanisms of bone growth and development, ultimately leading to discover innovative diagnostic and therapeutic tools for osteogenic disorders and bone diseases.

Compression loading of osteoclasts attenuated microRNA-146a-5p expression, which promotes angiogenesis by targeting adiponectin

Osteoclastogenesis in alveolar bone induced by compression stress triggers orthodontic tooth movement. Compression stress also stimulates angiogenesis, which is essential for osteoclastogenesis. However, the effects of osteoclastogenesis induced by compression on angiogenesis are poorly understood. In vivo, we found the markers of angiogenesis increased during orthodontic bone remodeling. In vitro, osteoclast-derived exosomes increased proliferation, migration, and tube formation of human umbilical vein endothelial cells (HUVECs), as well as expression of vascular endothelial growth factor and CD31. The promotive effects of exosomes derived from compressed osteoclasts were greater than those derived from osteoclasts without compression. Next, we analyzed changes in the microRNA transcriptome after compression stress and focused on microRNA146a-5p (miR-146a), which was significantly decreased by compression. Transfection of an inhibitor of miR-146a stimulated angiogenesis of HUVECs while miR-146a mimics repressed angiogenesis. Adiponectin (ADP) was confirmed to be a target of miR-146a by dual luciferase reporter assay. In HUVECs treated with exosomes, we detected increased ADP which promoted angiogenesis. Knockdown of ADP in HUVECs reduced the promotive effects of exosomes. Our results demonstrate that the decreased miR-146a observed in osteoclasts after compression promotes angiogenesis by targeting ADP, suggesting a novel method to interfere with bone remodeling induced by compression stress.

Long noncoding RNA expression profiles in intermittent parathyroid hormone induced cementogenesis

The aim of this study was to explore the involvement of long noncoding RNAs (lncRNAs) during intermittent parathyroid hormone (PTH) induced cementogenesis. Expression profiles of lncRNAs and mRNAs were obtained using high-throughput microarray. Gene Ontology enrichment analysis, Kyoto Encyclopedia of Genes and Genomes pathway analysis, and coding-noncoding gene coexpression networks construction were performed. We identified 190 lncRNAs and 135 mRNAs that were differentially expressed during intermittent PTH-induced cementogenesis. In this process, the Wnt signaling pathway was negatively regulated, and eight lncRNAs were identified as possible core regulators of Wnt signaling. Based on the results of microarrray analysis, we further verified the repressed expression of Wnt signaling crucial components β-catenin, APC and Axin2. Above all, we speculated that lncRNAs may play important roles in PTH-induced cementogenesis via the negative regulation of Wnt pathway.

Long Non-Coding RNA H19 Participates in Periodontal Inflammation via Activation of Autophagy

Purpose

Periodontitis is the leading cause of tooth loss. The role of long non-coding RNA (lncRNA) in periodontal inflammation remains unclear. The aim of this study was to investigate the role of lncRNA H19 in periodontitis and its possible regulation of autophagy in periodontitis.

Material and Methods

Inflammation level was determined by quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) in periodontal ligament cells (PDLCs). Western blotting, flow cytometric analysis, and immunofluorescence staining were used to detect the autophagy flux. Overexpression or knockdown of H19 was used to confirm its function. Ligature-induced periodontitis model in mice and periodontitis-affected human gingival tissue were used in vivo. RNA sequencing was performed to determine the differentially expressed genes.

Results

Autophagy was significantly increased in PDLCs after inflammatory stimulation as well as in a ligature-induced periodontitis model in mice and periodontitis-affected human gingival tissue. During the inflammatory process, H19 expression was also significantly upregulated. Further, the levels of autophagic markers were significantly upregulated after overexpressing H19 in PDLCs, and the increased autophagic activity induced by inflammatory stimulation was reversed by H19 knockdown. RNA sequencing showed that the expression profiles of mRNAs were significantly altered after H19 overexpression, and the differentially expressed genes were enriched in the PI3K/AKT signaling pathway, which was confirmed by the decreased p-AKT protein expression in the H19 overexpression group.

Conclusion

Periodontal inflammation activates autophagy flux, and H19 mediates the activation of autophagy via AKT pathway in periodontitis. This study expands our understanding of molecular regulation in periodontitis.

The regulatory roles of long noncoding RNAs in osteoporosis

Osteoporosis is a common metabolic bone disease characterized by low bone mineral density (BMD) and microarchitectural deterioration of bone tissue, which leads to decreased bone strength and increased fracture risk. Osteoporosis mainly results from a disruption of the balance between bone formation mediated by osteoblasts and bone resorption mediated by osteoclasts. At present, the molecular mechanisms underlying osteoporosis are still not fully understood. Long noncoding RNAs (lncRNAs) are RNA molecules that exceed 200 nucleotides (nt) in length and have limited or no protein-coding capacity. Over the past decade, numerous lncRNAs have been demonstrated to participate in multiple biological processes and to play essential roles in the pathogenesis of various diseases. In this review, we summarize recent progress in research on lncRNAs in osteoporosis and mainly focus on their regulatory roles in osteogenesis and osteoclastogenesis. Moreover, we briefly discuss the potential clinical applications of lncRNAs in osteoporosis.

Long non‑coding RNAs are novel players in oral inflammatory disorders, potentially premalignant oral epithelial lesions and oral squamous cell carcinoma (Review)

In recent years, a large number of studies have shown that the abnormal expression of long non‑coding (lnc)RNAs can lead to a variety of different diseases, including inflammatory disorders, cardiovascular disease, nervous system diseases, and cancers. Recent research has demonstrated the biological characteristics of lncRNAs and the important functions of lncRNAs in oral inflammation, precancerous lesions and cancers. The present review aims to explore and discuss the potential roles of candidate lncRNAs in oral diseases by summarizing multiple lncRNA profiles in diseased and healthy oral tissues to determine the altered lncRNA signatures. In addition, to highlight the exact regulatory mechanism of lncRNAs in oral inflammatory disorders, potentially premalignant oral epithelial lesions and oral squamous cell carcinoma. The detection of lncRNAs in oral samples has the potential to be used as a diagnostic and an early detection tool for oral diseases. Furthermore, lncRNAs are promising future therapeutic targets in oral diseases, and research in this field may expand in the future.