MiR-490-3p inhibits osteogenic differentiation in thoracic ligamentum flavum cells by targeting FOXO1

FOXO1 regulates RUNX2 ubiquitination through SMURF2 in calcific aortic valve disease

The prevalence of calcific aortic valve disease (CAVD) remains substantial while there is currently no medical therapy available. Forkhead box O1 (FOXO1) is known to be involved in the pathogenesis of cardiovascular diseases, including vascular calcification and atherosclerosis; however, its specific role in calcific aortic valve disease remains to be elucidated. In this study, we identified FOXO1 significantly down-regulated in the aortic valve interstitial cells (VICs) of calcified aortic valves by investigating clinical specimens and GEO database analysis. FOXO1 silencing or inhibition promoted VICs osteogenic differentiation in vitro and aortic valve calcification in Apoe-/- mice, respectively. We identified that FOXO1 facilitated the ubiquitination and degradation of RUNX2, which process was mainly mediated by SMAD-specific E3 ubiquitin ligase 2 (SMURF2). Our discoveries unveil a heretofore unacknowledged mechanism involving the FOXO1/SMURF2/RUNX2 axis in CAVD, thereby proposing the potential therapeutic utility of FOXO1 or SMURF2 as viable strategies to impede the progression of CAVD.

IL-6 is involved in thoracic ossification of the ligamentum flavum

Thoracic ossification of the ligamentum flavum (TOLF) is a heterotopic ossification of spinal ligaments. TOLF is the major cause of thoracic spinal canal stenosis and myelopathy, and its underlying mechanisms are not clear. Bone formation is a complex developmental process involving the differentiation of mesenchymal stem cells to osteoblasts, and regulated by BMP2, RUNX2, Osterix (OSX), etc. In this study, we continue to further characterize properties of TOLF. Our immunohistochemistry experiments showed that expressions of osteoblastic factors such as BMP2 and RUNX2 increased in TOLF. According to flow cytometry analysis the proportion of S phase of cell cycle in primary TOLF cells was 9% higher than the control. Alizarin red staining and ALP staining observations were consistent with immunohistochemistry results. It was also observed that inflammatory cytokine IL-6 level dramatically increased in the culture supernatant of primary TOLF cells. We propose the hypothesis that IL-6 is involved in TOLF. To testify the hypothesis, we examined the effect of IL-6. Our results showed that IL-6 was able to activate expressions of osteoblastic factors such as BMP2, RUNX2, OSX, OCN and ALP, and that expressions of cell proliferation factors cyclin D1 and cyclin C increased in the presence of IL-6. Moreover, IL-6-induced BMP2 expression was inhibited by p38 inhibitor SB203580, indicating that IL-6 regulated the osteogenic BMP2 activation through p38 MAPK pathway. These data suggest that IL-6 is involved in TOLF.

LGR5 regulates osteogenic differentiation of human thoracic ligamentum flavum cells by Wnt signalling pathway

Thoracic ossification of the ligamentum flavum (TOLF) is ectopic ossification of the spinal ligaments. Histologically, the development of TOLF can be described as the process of endochondral ossification. However, the underlying aetiology has not been completely clarified. In this investigation, the gene expression profile associated with leucine‐rich repeat‐containing G‐protein‐coupled receptors (LGR) and Wnt signalling pathway in the thoracic ligamentum flavum cells (TLFCs) of different ossification stages was analysed via RNA sequencing. We further confirmed the significant differences in the related gene expression profile by Gene Ontology (GO) enrichment analysis. LGR5 was first identified in primary human TLFCs during osteogenic differentiation. To evaluate the effect of LGR5 on osteogenic differentiation, LGR5 has been knocked down and overexpressed in human TLFCs. We observed that the knockdown of LGR5 inhibited the activity of Wnt signalling and attenuated the potential osteogenic differentiation of TLFCs, while overexpression of LGR5 activated the Wnt signalling pathway and increased osteogenic differentiation. Our results provide important evidence for the potent positive mediatory effects of LGR5 on osteogenesis by enhancing the Wnt signalling pathway in TOLF.

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.

Thoracic ossification of the ligamentum flavum causing acute myelopathy in a patient with cervical ossification of the posterior longitudinal ligament: illustrative case

BACKGROUND

Ossification of the ligamentum flavum (OLF) has been well characterized as a distinct entity but also in tandem with ossification of the posterior longitudinal ligament (OPLL) in noncontiguous spinal regions. The majority of OLF cases are reported from East Asian countries where prevalent, but such cases are rarely reported in the North American population.

OBSERVATIONS

The authors present a case of a Thai-Cambodian American who presented with symptomatic thoracic OLF in tandem with asymptomatic cervical OPLL. A “floating” thoracic laminectomy, resection of OLF, and partial dural ossification (DO) resection with circumferential release of ossified dura were performed. Radiographic dural reexpansion and spinal cord decompression occurred despite the immediate intraoperative appearance of persistent thecal sac compression from retained DO.

LESSONS

Entire spinal axis imaging should be considered for patients with spinal ligamentous ossification disease, particularly in those of East Asian backgrounds. A floating laminectomy is one of several surgical approaches for OLF, but no consensus approach has been clearly established. High surgical complication rates are associated with thoracic OLF, most commonly dural tears/cerebrospinal fluid (CSF) leaks. DO commonly coexists with OLF, is recognizable on computed tomographic scans, and increases the risk of CSF leaks.

Integrating Bioinformatic Strategies with Real-World Data to Infer Distinctive Immunocyte Infiltration Landscape and Immunologically Relevant Transcriptome Fingerprints in Ossification of Ligamentum Flavum

Purpose

Ossification of the ligamentum flavum (OLF) is a multifactorial disease characterized by an insidious and debilitating process of abnormal bone formation in ligamentum tissues. However, its definite pathogenesis has not been fully elucidated. Potential links between the immune system and various forms of heterotopic ossification have been discussed for many years, whereas no research investigated the immune effects on the initiation and development of OLF. Therefore, we attempt to shed light on this issue.

Methods

A series of bioinformatic algorithms were integrated to evaluate the immune score and the immunocyte infiltration patterns between OLF and normal samples, screen OLF-related and immune-related differentially expressed genes (OIDEGs), and analyze their biological functions. Correlation analysis inferred OIDEGs-related differentially expressed lncRNAs (OIDELs) and infiltrating immune cells (OIICs) to construct an immunoregulatory network.

Results

Differential immune score and immune cell infiltration were determined between two groups, and 10 OIDEGs with diverse biological function annotations were identified and verified. A lncRNA-gene-immunocyte regulatory network further revealed 10 OIDEGs, 41 OIDELs and 7 OIICs that were highly correlated. Among them, CD1E and STAT3 were predicted as hub genes whether at the expression level or interaction level. cDCs emerged as having the most prominent differences and the highest degree of connectivity. FO393414.3, AC096734.1, LINC01137 and DLX6-AS1 with the greatest number of OIDEGs were thought to be more likely to participate in immunoregulation of OLF.

Conclusion

This is the first research to preliminarily elucidate OLF-related immunocyte infiltration landscape and immune-associated transcriptome signatures based on bioinformatic strategies and real-world data, which may provide compelling insights into the pathogenesis and therapeutic targets of OLF.

Association analysis and functional study of COL6A1 single nucleotide polymorphisms in thoracic ossification of the ligamentum flavum in the Chinese Han population

PURPOSE

Genetic factors play a crucial role in thoracic ossification of the ligamentum flavum (TOLF). This study aimed to better understand the association between single nucleotide polymorphisms (SNP) in functional regions of the collagen VI, alpha 1 gene (COL6A1) and TOLF, and to confirm COL6A1 as a TOLF susceptibility gene.

METHODS

Ten tag SNPs in COL6A1 were genotyped using the SNaPshot assay, and allele and genotype frequencies were compared between TOLF patients and control individuals. The function of SNPs associated with disease was studied. For COL6A1 promoter SNPs, the transcriptional activity of each haplotype was determined by luciferase reporter assays. For COL6A1 exonic SNPs, the effect of nucleotide substitutions on COL6A1 expression was determined by western blotting. COL6A1 mRNA expression in ligamentum flavum tissues from TOLF patients with different genotypes was examined using reverse transcription real-time PCR.

RESULTS

Four SNPs were associated or possibly associated with TOLF, with higher pathogenic allele and genotype frequencies seen in TOLF patients compared with controls. The rs17551710/rs7671-GG/GG genotype appeared to be related to disease severity. Nucleotide substitutions at rs17551710 and rs7671 increased COL6A1 transcriptional activity and nucleotide substitutions at rs1053312 and rs13051496 increased COL6A1 protein expression. COL6A1 mRNA expression was significantly up-regulated in individuals with rs17551710/rs7671-GG/GG and rs1053312/rs13051496-AA+AG/CC genotypes compared with other genotypes.

CONCLUSION

SNPs in the COL6A1 promoter and exonic regions are associated with TOLF in the Chinese Han population, and lead to up-regulated COL6A1 expression. We confirmed COL6A1 as a TOLF susceptibility gene that may be involved in TOLF pathology.

Dysregulation of MicroRNAs in Hypertrophy and Ossification of Ligamentum Flavum: New Advances, Challenges, and Potential Directions

Pathological changes in the ligamentum flavum (LF) can be defined as a process of chronic progressive aberrations in the nature and structure of ligamentous tissues characterized by increased thickness, reduced elasticity, local calcification, or aggravated ossification, which may cause severe myelopathy, radiculopathy, or both. Hypertrophy of ligamentum flavum (HLF) and ossification of ligamentum flavum (OLF) are clinically common entities. Though accumulated evidence has indicated both genetic and environmental factors could contribute to the initiation and progression of HLF/OLF, the definite pathogenesis remains fully unclear. MicroRNAs (miRNAs), one of the important epigenetic modifications, are short single-stranded RNA molecules that regulate protein-coding gene expression at posttranscriptional level, which can disclose the mechanism underlying diseases, identify valuable biomarkers, and explore potential therapeutic targets. Considering that miRNAs play a central role in regulating gene expression, we summarized current studies from the point of view of miRNA-related molecular regulation networks in HLF/OLF. Exploratory studies revealed a variety of miRNA expression profiles and identified a battery of upregulated and downregulated miRNAs in OLF/HLF patients through microarray datasets or transcriptome sequencing. Experimental studies validated the roles of specific miRNAs (e.g., miR-132-3p, miR-199b-5p in OLF, miR-155, and miR-21 in HLF) in regulating fibrosis or osteogenesis differentiation of LF cells and related target genes or molecular signaling pathways. Finally, we discussed the perspectives and challenges of miRNA-based molecular mechanism, diagnostic biomarkers, and therapeutic targets of HLF/OLF.

Long-noncoding RNA Peg13 alleviates epilepsy progression in mice via the miR-490-3p/Psmd11 axis to inactivate the Wnt/β-catenin pathway

Epilepsy, one of the most common neurological diseases with spontaneous recurrent seizures, is a severe health problem globally. The present study aimed to study the role and upstream mechanism of 26S proteasome non-ATPase regulatory subunit 11 (Psmd11) in epilepsy. In the current paper, epileptic mice models were successfully established. Hematoxylin and eosin (HE) staining was performed to reveal morphology of hippocampal tissues. Nissl's staining was performed for detection of neuron injury. Enzyme-linked immunosorbent assay (ELISA) was conducted to detect concentrations of pro-inflammatory cytokines. The expression of Psmd11 was downregulated in the hippocampal tissues of epileptic mice, and overexpression of Psmd11 improved the spatial learning and memory of epileptic mice. Further, upregulation of Psmd11 protected epileptic hippocampal neurons from injury. Moreover, Psmd11 overexpression inhibited cell apoptosis, suppressed the activities of microglia and astrocytes, as well as reduced inflammatory response in epileptic hippocampi. Psmd11 was a downstream target of miR-490-3p. Long noncoding RNA (lncRNA) Peg13 bound with miR-490-3p to upregulate Psmd11. Subsequently, rescue experiments revealed that Peg13 suppressed the progression of epilepsy via upregulating Psmd11. Furthermore, Psmd11 was verified to inactivate the Wnt/β-catenin pathway. Peg13 repressed the Wnt/β-catenin pathway via upregulation of Peg13. In conclusion, this paper illuminated the function and upstream mechanism of Psmd11 in epilepsy. Psmd11 was upregulated by Peg13 at a miR-490-3p dependent way, thus inactivating the Wnt/β-catenin pathway and alleviating epilepsy course in mice, which may be a promising approach for epilepsy treatment.

miR-490: A potential biomarker and therapeutic target in cancer and other diseases

MicroRNAs (miRNAs) are small non-coding RNAs that function as posttranscriptional gene regulators. Among a pool of >2600 known human mature miRNAs, only a small subset have been functionally interrogated and a further smaller pool shown to be associated with the pathogenesis of a variety of diseases suggesting their critical role in maintaining homeostasis. Here, we draw your attention to one such miRNA, miR-490, that has been reported to be deregulated in a myriad of diseases (23 diseases) ranging from cardiomyopathy, depression, and developmental disorders to many cancer types (28 cancer types), such as hepatocellular carcinoma, gastric cancer, cancers of the reproductive and central nervous system among others. The prognostic and diagnostic potential of miR-490 has been reported in many diseases including cancer underlining its clinical relevance. We also collate a complex plethora of epigenetic (histone and DNA methylation), transcriptional (TF), and posttranscriptional (lncRNA and circRNA) mechanisms that have been shown to tightly regulate miR-490 levels. The targets of miR-490 involve a range of cancer-related genes involved in the regulation of various cancer hallmarks like cell proliferation, migration, and invasion, apoptotic cell death, angiogenesis, and so forth. Overall, our in-depth review highlights for the first time the emerging role of miR-490 in disease pathology, diagnosis, and prognosis that assigns a unique therapeutic potential to miR-490 in the era of precision medicine.

BMP2 Modified by the m6A Demethylation Enzyme ALKBH5 in the Ossification of the Ligamentum Flavum Through the AKT Signaling Pathway

Ossification of the ligamentum flavum (OLF) is characterized by a process of ectopic bone formation in the ligamentum flavum. The definitive pathophysiology of OLF still remains unclear, but the epigenetic m6A modification plays an important role in OLF. In addition, no studies have reported the function of ALKBH5 in OLF development. In this study, we investigated the function of the m6A demethylation enzyme ALKBH5 in OLF. To evaluate the function of ALKBH5, OLF tissues and normal ligamentum flavum tissues were collected. In vitro methods, including HE, IHC and western blotting assays, were used to evaluate the association of ALKBH5 with OLF. In addition, we verified the effects of ALKBH5 on osteogenesis using alizarin red and ALP staining. MeRIP q-PCR was performed to investigate the methylation level of BMP2. Moreover, the mechanism of ALKBH5-mediated regulation of the ossification of the ligamentum flavum cells through the AKT signaling pathway was also verified. The present study showed that the expression of ALKBH5 increased in OLF tissues. The overexpression of ALKBH5 increased the expression of osteogenic genes and promoted the ossification of ligamentum flavum cells. Furthermore, BMP2 was significantly enriched in the ligamentum flavum cells of the anti-m6A group compared with those of the IgG group. The overexpression of ALKBH5 led to the activation of p-AKT, and BMP2 was regulated by ALKBH5 through the AKT signaling pathway. ALKBH5 promoted the osteogenesis of the ligamentum flavum cells through BMP2 demethylation and AKT activation. ALKBH5 was shown to be an important demethylation enzyme in OLF development.

miR-378a-5p and miR-630 induce lens epithelial cell apoptosis in cataract via suppression of E2F3

Cataract, an eye disease that threatens the health of millions of people, brings about severe economic burden for patients and society. MicroRNA (miR)-378a-5p and miR-630 were recognized as essential regulators in multiple cancers. However, the exact functions of miR-378a-5p and miR-630 in cataract are still unclear. The expression of miR-378a-5p, miR-630, and E2F transcription factor 3 (E2F3) in tissues and cells was measured by quantitative real-time polymerase chain reaction. The 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide assay was used to evaluate cell viability. Flow cytometry was conducted to analyze cell apoptosis. The interaction between E2F3 and miR-378a-5p or miR-630 was confirmed by dual-luciferase reporter assay. The expression of proteins E2F3, B cell lymphoma (Bcl-2), Bcl-2 associated X (Bax), and cleaved caspase 3 was detected by western blot assay. The expression of miR-378a-5p and miR-630 was up-regulated whereas E2F3 was down-regulated in human cataract lens tissues compared with normal lens tissues. Depletion of miR-378a-5p or miR-630 enhanced proliferation and reduced apoptosis of human lens epithelial cells. Interestingly, up-regulation of E2F3 exhibited the same trend. Next, dual-luciferase reporter assay validated the interaction between E2F3 and miR-378a-5p or miR-630. The rescue experiments further revealed that E2F3 knockdown could recover miR-378a-5p, and miR-630 inhibitor induced promotion of cell proliferation and inhibition of apoptosis in cataract. miR-378a-5p and miR-630 repressed proliferation and induced apoptosis of lens epithelial cells by targeting E2F3 in cataract, representing a prospective alternative therapy for cataract.

Long noncoding RNA SNHG7 contributes to cell proliferation, migration, invasion and epithelial to mesenchymal transition in non-small cell lung cancer by regulating miR-449a/TGIF2 axis

Background

Non‐small cell lung cancer (NSCLC) is an intractable malignant lung cancer with high rates of metastasis and mortality. Currently, long noncoding RNA nuclear RNA host gene 7 (SNHG7) is recognized as a biomarker of multiple cancers. However, the role of SNHG7 in NSCLC requires further understanding.

Methods

The expression of SNHG7, miR‐449a and TGIF2 in NSCLC tumors and cells was examined by quantitative real time polymerase chain reaction (qRT‐PCR). Cell viability was measured by MTT assay. Cell migration and invasion was conducted using transwell assay. Protein expression of TGIF2, vimentin, N‐cadherin and E‐cadherin was detected by western blot. The interaction between miR‐449a and SNHG7 or TGIF2 was determined by luciferase reporter system, RIP and RNA pull‐down assay, respectively. Xenograft mice models were established by subcutaneously injecting A549 cells transfected with sh‐SNHG7 and sh‐control.

Results

SNHG7 expression was upregulated in NSCLC tumors and cells compared with normal tissues and cells. SNHG7 silencing repressed cell proliferation, migration, invasion and epithelial to mesenchymal transition (EMT) in NSCLC. Consistently, SNHG7 knockdown hindered tumor growth in vivo. The subsequent luciferase reporter system, RIP and RNA pull‐down assay validated the interaction between miR‐449a and SNHG7 or TGIF2. The rescue experiments displayed that miR‐449a inhibitor counteracted SNHG7 silencing induced inhibition on proliferation, migration, invasion and EMT. Similarly, restoration of TGIF2 reversed miR‐449a mediated inhibition on cell progression. In addition, the results indicated that SNHG7 could regulate cell progression by targeting miR‐449a/TGIF2 axis.

Conclusion

SNHG7 contributed to cell proliferation, migration, invasion and EMT in NSCLC by upregulating TGIF2 via sponging miR‐449a, representing a novel targeted therapy method for NSCLC.