Polyphyllin I alleviates neuroinflammation after cerebral ischemia-reperfusion injury via facilitating autophagy-mediated M2 microglial polarization.

Microglial activation and polarization play a central role in poststroke inflammation and neuronal damage. Modulating microglial polarization from pro-inflammatory to anti-inflammatory phenotype is a promising therapeutic strategy for the treatment of cerebral ischemia. Polyphyllin I (PPI), a steroidal saponin, shows multiple bioactivities in various diseases, but the potential function of PPI in cerebral ischemia is not elucidated yet. In our study, the influence of PPI on cerebral ischemia-reperfusion injury was evaluated. Mouse middle cerebral artery occlusion (MCAO) model and oxygen-glucose deprivation and reoxygenation (OGD/R) model were constructed to mimic cerebral ischemia-reperfusion injury in vivo and in vitro. TTC staining, TUNEL staining, RT-qPCR, ELISA, flow cytometry, western blot, immunofluorescence, hanging wire test, rotarod test and foot-fault test, open-field test and Morris water maze test were performed in our study. We found that PPI alleviated cerebral ischemia-reperfusion injury and neuroinflammation, and improved functional recovery of mice after MCAO. PPI modulated microglial polarization towards anti-inflammatory M2 phenotype in MCAO mice in vivo and post OGD/R in vitro. Besides, PPI promoted autophagy via suppressing Akt/mTOR signaling in microglia, while inhibition of autophagy abrogated the effect of PPI on M2 microglial polarization after OGD/R. Furthermore, PPI facilitated autophagy-mediated ROS clearance to inhibit NLRP3 inflammasome activation in microglia, and NLRP3 inflammasome reactivation by nigericin abolished the effect of PPI on M2 microglia polarization. In conclusion, PPI alleviated post-stroke neuroinflammation and tissue damage via increasing autophagy-mediated M2 microglial polarization. Our data suggested that PPI had potential for ischemic stroke treatment.

Polyphyllin I attenuates cognitive impairments and reduces AD-like pathology through CIP2A-PP2A signaling pathway in 3XTg-AD mice.

Polyphyllin I (PPI) is a natural phytochemical drug isolated from plants which can inhibit the proliferation of cancer cells. One of the PPI tumor-inhibitory effects is through downregulating the expression of Cancerous Inhibitor of PP2A (CIP2A), the latter, is found upregulated in Alzheimer's disease (AD) brains and participates in the development of AD. In this study, we explored the application of PPI in experimental AD treatment in CIP2A-overexpressed cells and 3XTg-AD mice. In CIP2A-overexpressed HEK293 cells or primary neurons, PPI effectively reduced CIP2A level, activated PP2A, and decreased the phosphorylation of tau/APP and the level of Aß. Furthermore, synaptic protein levels were restored by PPI in primary neurons overexpressing CIP2A. Animal experiments in 3XTg-AD mice revealed that PPI treatment resulted in decreased CIP2A expression and PP2A re-activation. With the modification of CIP2A-PP2A signaling, the hyperphosphorylation of tau/APP and Aß overproduction were prevented, and the cognitive impairments of 3XTg-AD mice were rescued. In summary, PPI ameliorated AD-like pathology and cognitive impairment through modulating CIP2A-PP2A signaling pathway. It may be a potential drug candidate for the treatment of AD.

Paris polyphylla ethanol extract and polyphyllin I ameliorate adenomyosis by inhibiting epithelial-mesenchymal transition.

BACKGROUND: The active ingredients of the Chinese medical herb Paris polyphylla, P. polyphylla ethanol extract (PPE) and polyphyllin I (PPI), potentially inhibit epithelial-mesenchymal transition (EMT) in tumors. However, the roles of these ingredients in inhibiting EMT in adenomyosis (AM) remain to be explored. PURPOSE: The primary goal of the study was to uncover the underlying molecular processes through which PPE and PPI suppress EMT in AM, alongside assessing the safety profiles of these substances. METHODS: To assess the suppressive impact of PPE on adenomyosis-derived cells (AMDCs), we employed Transwell and wound healing assays. The polyphyllins (PPI, PPII, PPVII) contained in PPE were characterized using high-performance liquid chromatography (HPLC). Then, bioinformatics techniques were performed to pinpoint potential PPI targets that could be effective in treating AM. Immunoblotting was used to verify the key proteins and pathways identified via bioinformatics. Furthermore, we examined the efficacy of PPE and PPI in treating Institute of Cancer Research (ICR) mice with AM by observing the morphological and pathological features of the uterus and performing immunohistochemistry. In addition, we assessed safety by evaluating liver, kidney and spleen pathologic features and serum test results. RESULTS: Three major polyphyllins of PPE were revealed by HPLC, and PPI had the highest concentration. In vitro experiments indicated that PPE and PPI effectively prevent AMDCs invasion and migration. Bioinformatics revealed that the primary targets E-cadherin, N-cadherin and TGFß1, as well as the EMT biological process, were enriched in PPI-treated AM. Immunoblotting assays corroborated the hypothesis that PPE and PPI suppress the TGFß1/Smad2/3 pathway in AMDCs to prevent EMT from progressing. Additionally, in vivo studies showed that PPE (3 mg/kg and 6 mg/kg) and PPI (3 mg/kg and 6 mg/kg), successfully suppressed the EMT process through targeting the TGFß1/Smad2/3 signaling pathway. Besides, it was observed that lower doses of PPE (3 mg/kg) and PPI (3 mg/kg) exerted minimal effects on the liver, kidneys, and spleen. CONCLUSIONS: PPE and PPI efficiently impede the development of EMT by inhibiting the TGFß1/Smad2/3 pathway, revealing an alternative pathway for the pharmacological treatment of AM.

The protective effect of polyphyllin I on myocardial ischemia/reperfusion injury in rats.

BACKGROUND: Myocardial ischemia/reperfusion (I/R) injury has become a global public health concern. An increasing amount of evidence has shown that polyphyllin I (PPI) has anti-apoptotic and antioxidant functions. This study was performed to evaluate the cardioprotective effects of PPI in a rat model of myocardial I/R injury and the underlying mechanism. METHODS: We exposed induced a rat model of I/R injury by exposing rat hearts to left anterior descending coronary artery ligation for 30 min, followed by 24 h of reperfusion. Cardiac function was analyzed by echocardiography and HE staining. Myocardial apoptosis, inflammation, and oxidative stress were detected to analyze the PPI's role in I/R injury. RESULTS: The results showed that pretreatment with PPI improved impaired histological morphology, as shown by histopathological examination. Echocardiography analysis showed that PPI increased the levels of HR, left ventricular ejection fraction (LVEF), and left ventricular wall thickness (LVWT), accompanied by decreased left ventricular end-systolic volume (LVESV). Also, PPI decreased the expression of CK-MB, Mb, cTnI, and LDH. Specifically, PPI also changed the expression of apoptotic makers (Caspase-3, Bax, and Bcl-2), inflammatory cytokines (TNF-α, IL-6, iNOS, and IL-10) and oxidative stress markers (SOD, GSH, ROS, and MDA). Notably, western blot (WB) showed that PPI treatment inhibited the phosphorylation activity of NF-κB p65. CONCLUSIONS: The findings showed that PPI exerted a favorable protective effect on I/R injury by inhibiting the inflammatory response and oxidative stress. It offered new drug candidates for the treatment of myocardial I/R injury.

Polyphyllin I (PPI) increased the sensitivity of hepatocellular carcinoma HepG2 cells to chemotherapy.

In this study the antitumor effects of polyphyllin I (PPI) were investigated in hepatocellular carcinoma HepG2 cells. Our data showed that PPI treatment exerted dose-dependent cytotoxicity on HepG2 cells as previously reported. Furthermore, PPI could sensitize HepG2 cells to cisplastin treatment in concentration-dependent manner. The molecular mechanisms of PPI actions involved nuclear factor-κB (NF-κB) and its downstream gene products. PPI treatment dose-dependently could decrease the constitutive phosphorylation of NF-κB subunit p65 protein and its downstream target genes expression, such as Bcl-2, c-Myc and VEGF. PPI could also inhibit cisplatin-evoked increase of p65 protein phosphorylation and its downstream genes expression, which could be further decreased by combination with NF-κB specific inhibitor, PDTC. The cytotoxicity and chemosensitization effects of PPI on HepG2 cells were greatly potentiated by concomitant treatment with PDTC. Taken together, our data confirmed the cytotoxicity of PPI on hepatocellular carcinoma HepG2 cells and provided new findings about PPI sensitizing HepG2 cells to chemotherapy. Moreover, our data also indicated the involvement of NF-κB signaling pathway in PPIactions for the first time.