miR-30a inhibits the osteogenic differentiation of the tibia-derived MSCs in congenital pseudarthrosis via targeting HOXD8

Circ_0003072 Mediates the Pro-osteogenic Differentiation Effect of Betulinic Acid on Human Periodontal Ligament Stem Cells

BACKGROUND

Betulinic acid (BetA) exhibits a good pro-osteogenic differentiation effect on human periodontal ligament stem cells (hPDLSCs), making it a promising supplement for periodontal regeneration. Circular RNAs (circRNAs) have emerged as important regulators of cellular behaviour, and whether circRNAs are involved in the effects of BetA remains unknown.

METHODS

Bioinformatics analysis was used to screen for dysregulated circRNAs involved in osteogenic differentiation based on public datasets. Osteogenic differentiation was evaluated using quantitative PCR detection of RUNX2, ALPL, COL1A1, and BGLAP levels, alkaline phosphatase staining, and Alizarin Red S staining of calcified nodules. The role of circ_0003072 in the BetA-regulated osteogenic differentiation of hPDLSCs was investigated, and its downstream microRNAs and mRNA were confirmed using RNA-sequencing, competing endogenous RNA network construction, gene ontology analysis, dual-luciferase reporter assays, and functional assays.

RESULTS

circ_0003072 showed the highest fold-change among the 18 candidate circRNAs, and knockdown of circ_0003072 inhibited the pro-osteogenic differentiation effect of BetA on hPDLSCs. RNA-sequencing combined with gene ontology analysis identified 11 osteogenesis-relevant genes. Five genes that shared microRNAs between circ_0003072 and two candidate genes (chordin-like 1 [CHRDL1] and XIAP) were screened, and miR-488-3p showed the highest increase after silencing circ_0003072. Knockdown of circ_0003072 inhibited the pro-osteogenic differentiation effect of silencing miR-488-3p. miR-488-3p bound to circ_0003072 and CHRDL1. Furthermore, overexpression of CHRDL1 rescued the miR-488-3p-induced inhibition of osteogenic differentiation.

CONCLUSION

BetA promoted the osteogenic differentiation of hPDLSCs by regulating the circ_0003072/miR-488-3p/CHRDL1 pathway, and circ_0003072 acted as a sponge for miR-488-3p, thus upregulating the level of CHRDL1.

The Expression Level of Inflammation-Related Genes in Patients With Bone Nonunion and the Effect of BMP-2 Infected Mesenchymal Stem Cells Combined With nHA/PA66 on the Inflammation Level of Femoral Bone Nonunion Rats

Bone nonunion delays fracture end repair and is associated with inflammation. Although bone nonunion can be effectively repaired in clinical practice, many cases of failure. Studies have confirmed that BMP-2 and nHA/PA66 repaired bone defects successfully. There are few studies on the effects of the combined application of BMP-2 and NHA/PA66 on bone nonunion osteogenesis and inflammation. We aimed to investigate the expression level of inflammation-related genes in patients with bone nonunion and the effect of BMP-2-infected mesenchymal stem cells combined with nHA/PA66 on the level of inflammation in femur nonunion rats. We searched for a gene expression profile related to bone nonunion inflammation (GSE93138) in the GEO public database. Bone marrow mesenchymal stem cells (MSCs) of SD rats were cultured and passed through. We infected the third generation of MSCs with lentivirus carrying BMP-2 and induced the infected MSCs to bone orientation. We detected the expression level of BMP-2 by RT-PCR and the cell viability and alkaline phosphatase (ALP) activity by CCK8 and then analyzed the cell adhesion ability. Finally, the levels of related inflammatory factors, including C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha) and Erythrocyte Sedimentation Rate (ESR), were detected in nonunion rats. Our findings: The patients with nonunion had up-regulated expression of 26 differentially inflammatory genes. These genes are mainly enriched in innate immune response, extracellular region, calcium ion binding, Pantothenate and CoA biosynthesis pathways. The expression level of BMP-2 in the Lenti-BMP-2 group was higher (vs. empty lentivirus vector group: t=5.699; vs. uninfected group t=3.996). The cell activity of the MSCs + BMP-2 + nHA/PA66 group increased gradually. After being combined with nHA/PA66, MSCs transfected with BMP-2 spread all over the surface of nHA/PA66 and grew into the material pores. MSCs + BMP-2 + nHA/PA66 cells showed positive ALP staining, and the OD value of ALP was the highest. The levels of CRP, IL-6, TNF-alpha, and ESR in the MSCs + BMP-2 + nHA/PA66 group were lower than those in the MSCs and MSCs + nHA/PA66 group but higher than those in MSCs + BMP-2 group. The above comparisons were all P<0.05. The findings demonstrated that the expression level of inflammation-related genes increased in the patients with bone nonunion. The infection of MSCs by BMP-2 could promote the directed differentiation of MSCs into osteoblasts in the bone marrow of rats, enhance the cell adhesion ability and ALP activity, and reduce inflammation in rats with bone nonunion.

METTL3 promotes the osteogenic differentiation of periosteum-derived MSCs via regulation of the HOXD8/ITGA5 axis in congenital pseudarthrosis

Background

Congenital pseudarthrosis of the tibia (CPT) is a dominant health challenge in pediatric orthopedics. The essential process in the development of CPT is the limited capacity of mesenchymal stem cells (MSCs) derived from CPT to undergo osteogenic differentiation. Our research aimed to elucidate the role and mechanism of methyltransferase-like 3 (METTL3) in the osteogenic differentiation process of CPT MSCs.

Methods

The osteogenic differentiation medium was used to culture MSCs, and the detection of osteogenic differentiation was performed using Alizarin Red S and alkaline phosphatase (ALP) assays. Gene or protein expression was assessed by quantitative real-time polymerase chain reaction (qRT-PCR), Western blot, or immunofluorescence (IF) staining. The m6A modification of Homeobox D8 (HOXD8) was verified by methylated RNA immunoprecipitation (MeRIP) assay. Interactions between METTL3 and HOXD8 or HOXD8 and integrin alpha 5 (ITGA5) promoter were validated by the luciferase reporter gene, RIP, and chromatin immunoprecipitation (ChIP) assays.

Results

METTL3 overexpression enhanced CPT MSCs' osteogenic differentiation. METTL3 stabilized the HOXD8 in an m6A-dependent manner. Moreover, the overexpressed ITGA5 up-regulated the CPT MSCs' osteogenic differentiation. Further, HOXD8 could transcriptionally activate ITGA5. METTL3 increased the transcription of ITGA5 via HOXD8 to enhance the osteogenic differentiation of CPT MSCs.

Conclusion

METTL3 promoted osteogenic differentiation via modulating the HOXD8/ITGA5 axis in CPT MSCs.

Serum microRNA profile of rhesus macaques following ionizing radiation exposure and treatment with a medical countermeasure, Ex-Rad

Exposure to ionizing radiation (IR) presents a formidable clinical challenge. Total-body or significant partial-body exposure at a high dose and dose rate leads to acute radiation syndrome (ARS), the complex pathologic effects that arise following IR exposure over a short period of time. Early and accurate diagnosis of ARS is critical for assessing the exposure dose and determining the proper treatment. Serum microRNAs (miRNAs) may effectively predict the impact of irradiation and assess cell viability/senescence changes and inflammation. We used a nonhuman primate (NHP) model-rhesus macaques (Macaca mulatta)-to identify the serum miRNA landscape 96 h prior to and following 7.2 Gy total-body irradiation (TBI) at four timepoints: 24, 36, 48, and 96 h. To assess whether the miRNA profile reflects the therapeutic effect of a small molecule ON01210, commonly known as Ex-Rad, that has demonstrated radioprotective efficacy in a rodent model, we administered Ex-Rad at two different schedules of NHPs; either 36 and 48 h post-irradiation or 48 and 60 h post-irradiation. Results of this study corroborated our previous findings obtained using a qPCR array for several miRNAs and their modulation in response to irradiation: some miRNAs demonstrated a temporary increased serum concentration within the first 24-36 h (miR-375, miR-185-5p), whereas others displayed either a prolonged decline (miR-423-5p) or a long-term increase (miR-30a-5p, miR-27b-3p). In agreement with these time-dependent changes, hierarchical clustering of differentially expressed miRNAs showed that the profiles of the top six miRNA that most strongly correlated with radiation exposure were inconsistent between the 24 and 96 h timepoints following exposure, suggesting that different biodosimetry miRNA markers might be required depending on the time that has elapsed. Finally, Ex-Rad treatment restored the level of several miRNAs whose expression was significantly changed after radiation exposure, including miR-16-2, an miRNA previously associated with radiation survival. Taken together, our findings support the use of miRNA expression as an indicator of radiation exposure and the use of Ex-Rad as a potential radioprotectant.

Integrative analysis from multi-center studies identifies a weighted gene co-expression network analysis-based Tregs signature in ovarian cancer

Ovarian cancer (OC) is a malignancy associated with poor prognosis and has been linked to regulatory T cells (Tregs) in the immune microenvironment. Nevertheless, the association between Tregs-related genes (TRGs) and OC prognosis remains incompletely understood. The xCell algorithm was used to analyze Tregs scores across multiple cohorts. Weighted gene co-expression network analysis (WGCNA) was utilized to identify potential TRGs and molecular subtypes. Furthermore, we used nine machine learning algorithms to create risk models with prognostic indicators for patients. Reverse transcription-quantitative polymerase chain reaction and immunofluorescence staining were used to demonstrate the immunosuppressive ability of Tregs and the expression of key TRGs in clinical samples. Our study found that higher Tregs scores were significantly correlated with poorer overall survival. Recurrent patients exhibited increased Tregs infiltration and reduced CD8+ T cell. Moreover, molecular subtyping using seven key TRGs revealed that subtype B exhibited higher enrichment of multiple oncogenic pathways and had a worse prognosis. Notably, subtype B exhibited high Tregs levels, suggesting immune suppression. In addition, we validated machine learning-derived prognostic models across multiple platform cohorts to better distinguish patient survival and predict immunotherapy efficacy. Finally, the differential expression of key TRGs was validated using clinical samples. Our study provides novel insights into the role of Tregs in the immune microenvironment of OC. We identified potential therapeutic targets derived from Tregs (CD24, FHL2, GPM6A, HOXD8, NAP1L5, REN, and TOX3) for personalized treatment and created a machining learning-based prognostic model for OC patients, which could be useful in clinical practice.