Specnuezhenide ameliorates ultraviolet-induced skin photoaging in mice by regulating the Sirtuin 3/8-Oxoguanine DNA glycosylase signal

Single-cell sequencing reveals that specnuezhenide protects against osteoporosis via activation of METTL3 in LEPR+ BMSCs

BACKGROUND

Osteoporosis (OP) has garnered significant attention due to its substantial morbidity and mortality rates, imposing considerable health burdens on societies worldwide. However, the molecular mechanisms underlying osteoporosis pathogenesis remain largely elusive, and the available therapeutic interventions are limited. Therefore, there is an urgent need for innovative strategies in the treatment of osteoporosis.

PURPOSE

The primary objective of this study was to elucidate the molecular mechanisms underlying osteoporosis pathogenesis using single-cell RNA sequencing (scRNA-seq), thereby proposing novel therapeutic agents.

METHODS

The mice osteoporosis model was established through bilateral ovariectomy. Micro-computed tomography (μCT) and hematoxylin and eosin (H&E) staining were employed to assess the pathogenesis of osteoporosis. scRNA-seq was utilized to identify and analyze distinct molecular mechanisms and sub-clusters. Gradient dilution analysis was used to obtain specific sub-clusters, which were further validated by immunofluorescence staining and flow cytometry analysis. Molecular docking and cellular thermal shift assay (CETSA) were applied for screening potential agents in the TCMSPs database. Alkaline phosphatase (ALP) activity and alizarin red S (ARS) staining were performed to evaluate the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). Osteogenic organoids analysis was employed to assess the proliferation and sphere-forming ability of BMSCs. Quantitative real-time PCR (qRT-PCR) and western blot analysis were conducted to investigate signaling pathways. Wound healing assay and tube formation analysis were employed to evaluate the angiogenesis of endothelial cells.

RESULTS

The scRNA-seq analysis revealed the crucial role of LEPR+ BMSCs in the pathogenesis of osteoporosis, which was confirmed by immunofluorescence staining of the epiphysis. Subsequently, the LEPR+ BMSCs were obtained by gradient dilution analysis and identified by immunofluorescence staining and flow cytometry. Accordingly, specnuezhenide (Spe) was screened and identified as a potential compound targeting METTL3 from the TCMSPs database. Spe promoted bone formation as evidenced by μ-CT, and H&E analysis. Additionally, Spe enhanced the osteogenic capacity of LEPR+ BMSCs through ALP and ARS assay. Notably, METTL3 pharmacological inhibitors S-Adenosylhomocysteine (SAH) attenuated the aforementioned osteo-protective effects of Spe. Particularly, Spe enhanced the LEPR+ BMSCs-dependent angiogenesis through the secretion of SLIT3, which was abolished by SAH in LEPR+ BMSCs.

CONCLUSION

Collectively, these findings suggest that Spe could enhance the osteogenic potential of LEPR+ BMSCs and promote LEPR+ BMSCs-dependent angiogenesis by activating METTL3 in LEPR+ BMSCs, indicating its potential as an ideal therapeutic agent for clinical treatment of osteoporosis.

Establishment of a multicomponent quality control method and the transfer characteristics of five markers from Qidongning Formula to rat tissues by HPLC-QQQ-MS/MS

Introduction: Traditional Chinese medicine compound preparations have become an increasingly utilized strategy for tumour treatment. Qidongning Formula (QDN) is a kind of antitumour compound preparation used in hospitals, and it can inhibit the growth of lung cancer cells. However, due to the complexity of botanical drugs, the quality evaluation of QDN is inconsistent, affecting clinical efficacy and posing potential safety risks for clinical application. Additionally, tissue distribution is an integral part of the drug development process. Methods: To study the distribution characteristics of markers in compound preparations and rat tissues, a novel HPLC-QQQ-MS/MS quantitative analytical method was established to determine five markers in QDN simultaneously, and the method was verified. Results and discussion: The analytical results showed that the contents of salidroside (51.6 ± 5.75 μg/g), calycosin-7-O-β-D-glucoside (94.2 ± 15.4 μg/g), specnuezhenide (371 ± 72.5 μg/g), formononetin (23.8 ± 5.39 μg/g), and polyphyllin I (87.7 ± 10.6 μg/g) were stable in different batches of QDN. After intragastric administration (13.5 g/kg) in rats for 1 h, four markers in the QDN, except polyphyllin I, were distributed in most tissues. QDN was distributed chiefly in the stomach and small intestine, followed by the liver or kidney. The study also found that specnuezhenide had the highest concentration in both QDN and rat tissues (102 ± 22.1 μg/g in the stomach), while formononetin had the highest transfer rate (0.351%) from QDN to rat intestines. The above research lays a quality research foundation for the antitumour application of QDN and provides a scientific reference for the quality control of Chinese medicine compound preparations.