miR-126 mitigates the osteogenic differentiation of human bone marrow-derived mesenchymal stem cells by targeting the ERK1/2 and Bcl-2 pathways

Mir-381-3p aggravates ovariectomy-induced osteoporosis by inhibiting osteogenic differentiation through targeting KLF5/Wnt/β-catenin signaling pathway

BACKGROUND

Increasing evidence shows the pivotal significance of miRNAs in the pathogenesis of osteoporosis. miR-381-3p has been identified as an inhibitor of osteogenesis. This study explored the role and mechanism of miR-381-3p in postmenopausal osteoporosis (PMOP), the most common type of osteoporosis.

METHODS

Bilateral ovariectomy (OVX) rat model was established and miR-381-3p antagomir was administrated through the tail vein in vivo. The pathological changes in rats were assessed through the evaluation of serum bone turnover markers (BALP, PINP, and CTX-1), hematoxylin and eosin (H&E) staining, as well as the expression of osteoblast differentiation biomarkers. Moreover, isolated bone marrow mesenchymal stem cells from OVX-induced rats (OVX-BMMSCs) were utilized to explore the impact of miR-381-3p on osteoblast differentiation. In addition, the target gene and downstream pathway of miR-381-3p were further investigated both in vivo and in vitro.

RESULTS

miR-381-3p expression was elevated, whereas KLF5 was suppressed in OVX rats. miR-381-3p antagomir decreased serum levels of bone turnover markers, improved trabecular separation, promoted osteoblast differentiation biomarker expression in OVX rats. ALP activity and mineralization were suppressed, and levels of osteoblast differentiation biomarkers were impeded after miR-381-3p overexpression during osteoblast differentiation of OVX-BMMSCs. While contrasting results were found after inhibition of miR-381-3p. miR-381-3p targets KLF5, negatively affecting its expression as well as its downstream Wnt/β-catenin pathway, both in vivo and in vitro. Silencing of KLF5 restored Wnt/β-catenin activation induced by miR-381-3p antagomir.

CONCLUSION

miR-381-3p aggravates PMOP by inhibiting osteogenic differentiation through targeting KLF5/Wnt/β-catenin pathway. miR-381-3p appears to be a promising candidate for therapeutic intervention in PMOP.

Photocrosslinked gelatin/chondroitin sulfate/chitosan-based composites with tunable multifunctionality for bone tissue regeneration

Novel hydrogel-based multifunctional systems prepared utilizing photocrosslinking and freeze-drying processes (PhotoCross/Freeze-dried) dedicated for bone tissue regeneration are presented. Fabricated materials, composed of methacrylated gelatin, chitosan, and chondroitin sulfate, possess interesting features including bioactivity, biocompatibility, as well as antibacterial activity. Importantly, their degradation and swellability might be easily tuned by playing with the biopolymeric content in the photocrosllinked systems. To broaden the potential application and deliver the therapeutic features, mesoporous silica particles functionalized with methacrylate moieties decorated with hydroxyapatite and loaded with the antiosteoporotic drug, alendronate, (MSP-MA-HAp-ALN) were dispersed within the biopolymeric sol and photocrosslinked. It was demonstrated that the obtained composites are characterized by a significantly extended degradation time, ensuring optimal conditions for balancing hybrids removal with the deposition of fresh bone. We have shown that attachment of MSP-MA-HAp-ALN to the polymeric matrix minimizes the initial burst effect and provides a prolonged release of ALN (up to 22 days). Moreover, the biological evaluation in vitro suggested the capability of the resulted systems to promote bone remodeling. Developed materials might potentially serve as scaffolds that after implantation will fill up bone defects of various origin (osteoporosis, tumour resection, accidents) providing the favourable conditions for bone regeneration and supporting the infections' treatment.

Investigating the Differential Circulating microRNA Expression in Adolescent Females with Severe Idiopathic Scoliosis: A Proof-of-Concept Observational Clinical Study

Adolescent Idiopathic Scoliosis (AIS) is the most common form of three-dimensional spinal disorder in adolescents between the ages of 10 and 18 years of age, most commonly diagnosed in young women when severe disease occurs. Patients with AIS are characterized by abnormal skeletal growth and reduced bone mineral density. The etiology of AIS is thought to be multifactorial, involving both environmental and genetic factors, but to date, it is still unknown. Therefore, it is crucial to further investigate the molecular pathogenesis of AIS and to identify biomarkers useful for predicting curve progression. In this perspective, the relative abundance of a panel of microRNAs (miRNAs) was analyzed in the plasma of 20 AIS patients and 10 healthy controls (HC). The data revealed a significant group of circulating miRNAs dysregulated in AIS patients compared to HC. Further bioinformatic analyses evidenced a more restricted expression of some miRNAs exclusively in severe AIS females. These include some members of the miR-30 family, which are considered promising regulators for treating bone diseases. We demonstrated circulating extracellular vesicles (EVs) from severe AIS females contained miR-30 family members and decreased the osteogenic differentiation of mesenchymal stem cells. Proteomic analysis of EVs highlighted the expression of proteins associated with orthopedic disease. This study provides preliminary evidence of a miRNAs signature potentially associated with severe female AIS and suggests the corresponding vesicular component may affect cellular mechanisms crucial in AIS, opening the scenario for in-depth studies on prognostic differences related to gender and grade.