Soy isoflavones induces mitophagy to inhibit the progression of osteosarcoma by blocking the AKT/mTOR signaling pathway.

BACKGROUND: Soy isoflavones (SI) is a natural bioactive substance exhibiting beneficial effects on human health. This study aims to elucidate the therapeutic potential of SI in the treatment of osteosarcoma (OS) and to investigate the underlying mechanisms, particularly focusing on mitophagy. METHODS: The effects of SI on the proliferation, apoptosis, migration, and invasion of U2OS cells were analyzed. Mitophagy was assessed through multiple parameters: mitochondrial autophagosomes, mitochondrial membrane potential, autophagy-related proteins, reactive oxygen species (ROS), and oxygen consumption rate (OCR). Protein levels related to apoptosis, autophagy, and the AKT/mTOR pathway were analyzed using western blot. The therapeutic efficacy of SI was further identified using a mouse tumor xenograft model. Cell apoptosis and proliferation in tumor xenografts were detected by TUNEL staining and immunohistochemistry (IHC), respectively. RESULTS: SI dose-dependently suppressed the viability, colony formation, migration, and invasion of U2OS cells, and enhanced the apoptosis. SI also dose-dependently induced mitophagy in OS cells, evidenced by an increase in autophagosomes and ROS levels, a decrease in mitochondrial membrane potential and OCR, and concomitant changes in autophagy-related proteins. Mdivi-1, an inhibitor of mitophagy, reversed the anti-tumor effects of SI on U2OS cells. In addition, SI blocked the AKT/mTOR pathway in U2OS cells. SC-79, an AKT agonist, reversed the effect of SI on inducing mitophagy. Moreover, SI also promoted cell apoptosis and mitophagy in tumor xenografts in vivo. CONCLUSIONS: SI induces mitophagy in OS cells by blocking the AKT/mTOR pathway, contributing to the inhibition of OS.

NLRP3 inflammasome blocked the glycolytic pathway via targeting to PKLR in arsenic-induced hepatic insulin resistance.

Arsenic exposure is related to insulin resistance (IR). However, the underlying mechanism is still uncertain. NOD-like receptors containing pyrin domain 3 (NLRP3) inflammasome is a key driving factor of IR. We found that NaAsO2 caused hepatic IR, activated NLRP3 inflammasome, and inhibited glycolysis pathway in vivo. We also found that tricarboxylic acid cycle (TCA cycle) was inhibited, and the content of hepatic lactate was upregulated with the treatment of arsenic. Consistent with these findings, we found that NLRP3 inflammasome and glycolysis were involved in the development of IR in L-02 cells. Besides, inhibiting NLRP3 inflammasome upregulated aerobic glycolysis and inhibited anaerobic glycolysis. Moreover, we demonstrated that NLRP3 inflammasome could bind to pyruvate kinase, liver and RBC (PKLR). Simultaneously, insulin signaling rather than NLRP3 inflammasome activation was altered by overexpressing PKLR. In summary, after treatment with NaAsO2, NLRP3 inflammasome blocked the glycolytic pathway via binding to PKLR, which in turn caused hepatic IR. This study shed new light on the molecular mechanism underlying arsenic-induced IR.

MFAP2 induces epithelial-mesenchymal transformation of osteosarcoma cells by activating the Notch1 pathway.

Background: Osteosarcoma (OS) is a malignancy originating from mesenchymal tissue. Microfibril-associated protein 2 (MFAP2) plays a crucial role in cancer, notably promoting epithelial-mesenchymal transition (EMT). However, its involvement in OS remains unexplored. Methods: MFAP2 was silenced in U2OS cells using shRNA targeting MFAP2 (sh-MFAP2) and validated by quantitative real-time polymerase chain reaction (qRT-PCR). We extracted gene chip data of MFAP2 from multiple databases (GSE28424, GSE42572, and GSE126209). Correlation analyses between MFAP2 and the Notch1 pathway identified through the gene set variation analysis (GSVA) enrichment analysis were conducted using the Pearson correlation method. Cellular behaviors (viability, migration, and invasion) were assessed via the Cell Counting Kit-8 (CCK-8), wound healing, and Transwell assays. EMT markers (N-cadherin, vimentin, and ß-catenin) and Notch1 levels were examined by western blotting and qRT-PCR. Cell morphology was observed microscopically to evaluate EMT. Finally, the role of MFAP2 in OS was validated through a xenograft tumor model. Results: OS cell lines exhibited higher MFAP2 mRNA expression than normal osteoblasts. MFAP2 knockdown in U2OS cells significantly reduced viability, migration, and invasion, along with downregulation of N-cadherin and vimentin, as well as upregulation of ß-catenin. MFAP2 significantly correlated with the Notch1 pathway in OS and its knockdown inhibited Notch1 protein expression. Furthermore, Notch1 activation reversed the inhibitory effects of MFAP2 knockdown on the malignant characteristic of U2OS cells. Additionally, MFAP2 knockdown inhibited tumor growth, expression levels of EMT markers, and Notch1 expression in OS tumor tissues. Conclusions: Our study revealed that MFAP2 was an upstream regulator of the Notch1 signaling pathway to promote EMT in OS. These findings suggested MFAP2 as a potential OS therapy target.

Exploring the biological diversity and source species of medicinal horseflies through metabarcoding.

Horseflies from the Tabanidae family play a significant role in traditional Chinese medicine to treat various health conditions, including coronary heart disease, stroke, headaches, liver cirrhosis, psoriasis, and hepatic carcinoma. There are 27 species of Tabaninae (Tabanidae) used as medicine, and they showed high morphological similarities with those for which medicinal properties have not been reported. Nonetheless, there have been reports suggesting that medicinal crude drugs sometimes contain irrelevant or false species, impacting the drug's efficacy. In this current study, we collected 14 batches, totaling 13,528 individuals, from various provinces in China. Instead of "classic" DNA barcoding strategy, we employed a high-throughput metabarcoding approach to assess the biological composition of crude drug mixtures derived from horseflies. Our analysis identified 40 Amplicon Sequence Variants (ASVs) with similarity percentages ranging from 92% to 100% with 12 previously reported species. Species delimitation methods revealed the presence of 11 Molecular Operational Taxonomic Units (MOTUs), with ten belonging to the Tabanus genus and one to Hybomitra. Tabanus sp6 displayed the highest relative abundance, and its ASVs showed close resemblance to Tabanus pleski. Our investigations revealed that the medicinal batches were biologically composed of 6 to 12 species. Some batches contained ASVs that closely resembled species previously associated with false Tabanus species. In conclusion, our findings offer valuable insights into the biological composition of crude drugs derived from horseflies and have the potential to enhance the quality of these traditional medicines.

The metabarcoding of Grubs: Traditional herbal medicine of Scarabaeidae larvae.

Grubs, called Qicao in China, have a long tradition as herbal medicine in East Asia. These larvae belong to the diverse family Scarabaeidae and are typically harvested from the wild during their immature stage based on morphological characteristics. However, rapid and accurate identification becomes challenging when relying solely on external morphological features, as the lack of clarity on biological sources raises safety concerns for clinical applications. The application of DNA metabarcoding provides a solution by enabling the determination of the biological source of a large sample. In the current study, we collected 19 batches of Grubs, consisting of 11,539 individuals, from the market and analyzed their biological composition through metabarcoding. We identified 49 Amplicon Sequence Variants (ASVs), 21 of which were Grubs. The 21 ASVs were classified into seven Molecular Operational Taxonomic Units (MOTUs) through species delimitation, which revealed that commercially available Grubs are predominantly sourced from Protaetia brevitarsis seulensis, while species of Rutelinae, Anomala, and Holotrichia were also abundant in some commercial batches. Among the identified ASVs, 28 belonged to non-Grub species and indicated adulteration from different animal families; high abundances of these ASVs were detected for Bombycidae, Tabanidae, and Viviparidae. Our findings underscore the complexity of Grubs' species composition and advocate for a deeper understanding of the wildlife sources contributing to herbal products. This research contributes valuable insights into the molecular identification of Grubs, paving the way for enhanced quality assurance in traditional medicine applications to provide safe and effective medicines for humanity.

Taurine attenuates arsenic-induced pyroptosis and nonalcoholic steatohepatitis by inhibiting the autophagic-inflammasomal pathway.

Arsenic exposure causes nonalcoholic steatohepatitis (NASH). Inflammation is a key contributor to the pathology of nonalcoholic fatty liver disease (NAFLD), including NASH. However, it is unclear how arsenic induces inflammation. In mouse livers, we show that arsenic trioxide (As2O3) induced NASH, increased autophagy and NLRP3 inflammasome activation, increased lipid accumulation, and resulted in dysregulation of lipid-related genes. Supplemented with taurine (Tau) attenuated the inflammation and autophagy caused by As2O3. In HepG2 cells, we found that As2O3-induced pyroptotic cell death was dependent upon the activation of NLRP3 inflammasome, which was CTSB-dependent. In addition, inhibiting autophagy alleviated the As2O3-induced increase of cytosolic CTSB expression and subsequent release of LDH, activation of the NLRP3 inflammasome, and pyroptosis. Moreover, we found that Tau alleviated As2O3-induced elevation of autophagy, CTSB expression, and activation of the NLRP3 inflammasome, and reduced the release of LDH, pyroptotic cell death, and inflammation. Interestingly, As2O3-induced lipid accumulation could not be alleviated by either inhibition of autophagy nor by inhibition of CTSB. Additionally, neither inhibition of the NLRP3 inflammasome or Tau treatment could alleviate lipid accumulation. These results demonstrated that As2O3-induced pyroptosis involves autophagy, CTSB, and the NLRP3 inflammasome cascade, and that Tau alleviates As2O3-induced liver inflammation by inhibiting the autophagic-CTSB-NLRP3 inflammasomal pathway rather than decreasing lipid accumulation. These findings give insight into the association of autophagy, inflammation, pyroptosis, and NASH induced by As2O3.