Exosomal STAT1 derived from high phosphorus­stimulated vascular endothelial cells induces vascular smooth muscle cell calcification via the Wnt/ß­catenin signaling pathway.

Vascular calcification is commonly observed in chronic kidney disease. The mechanism of how the calcification signal from endothelial cells is transmitted to vascular smooth muscle cells (VSMCs) remains unknown. The aim of the present study was to investigate whether exosomes from HUVECs (HUVEC­Exos) could regulate VSMC calcification and its potential signaling pathway. HUVEC­Exos were isolated from HUVECs under no phosphorus (NP) and high phosphorus (HP) conditions. Alizarin Red S staining and calcium (Ca) content analysis were carried out to detect calcification in VSMCs. Proteomics analysis was carried out to detect the differential expression of exosomal proteins. Protein and mRNA levels were measured by western blot analysis and reverse transcription­quantitative PCR (RT­qPCR). Exosomes derived from HP­HUVECs promoted the calcification of VSMCs, as assessed by Alizarin Red S staining, alkaline phosphatase activity assays, Ca content measurements and the increased expression of runt­related transcription factor 2 and osteopontin. Proteomic analysis detected the upregulation of STAT1 in HP­exosomes from HUVECs (HUVEC­Exos) compared with NP­HUVEC­Exos, which was also confirmed by western blot analysis and RT­qPCR. Inhibition of STAT1 expression in VSMCs using fludarabine or knockdown of STAT1 expression using small interfering RNA alleviated the calcification of VSMCs. Furthermore, lithium chloride (Wnt activator) reversed the protective effect of STAT1 inhibition on VSMC calcification, while Dickkopf­1 (Wnt inhibitor) exerted the opposite effect, suggesting that activation of the Wnt/ß­catenin signaling pathway was involved in STAT1­mediated VSMC calcification. In conclusion, the present results indicated that exosomal STAT1 derived from HP­treated HUVECs could promote VSMC calcification, and activation of the Wnt/ß­catenin pathway may be a potential mechanism of the VSMC calcification promoted by exosomes.

Associations Between 25-Hydroxyvitamin D, Kidney Function, and Insulin Resistance Among Adults in the United States of America.

BACKGROUND: Although many molecular studies have tried to explore the relationship between vitamin D metabolism and kidney function, the association between 25-hydroxyvitamin D [25(OH)D] and kidney function is still controversial. Previous studies reported that low vitamin D status and decreased kidney function were associated with insulin resistance (IR). However, neither of them was confirmed by large population-based studies. This study evaluated the associations between 25(OH)D and kidney function and the associations between both of them and IR among adults in the United States of America (USA). METHODS: We analyzed 36,523 adults from the National Health and Nutrition Examination Survey (NHANES) (2001-2014). Kidney function was assessed by the estimated glomerular filtration rate (eGFR), and IR was assessed by homeostasis model assessment (HOMA-IR). All data were survey-weighted, and corresponding linear regression models were performed to examine the associations. RESULTS: The mean serum 25(OH)D levels were found to be increased in participants with decreased kidney function (eGFR <90 ml/min/1.73 m2), and each unit of decreased serum 25(OH)D concentrations predicted 0.453 ml/min/1.73 m2 (95% CI: 0.426 to 0.480, p < 0.0001) higher eGFR. In addition, each unit of decreased eGFR was associated with 0.007 higher HOMA-IR, while each unit of decreased 25(OH)D concentrations led to 0.025 higher HOMA-IR. CONCLUSIONS: Serum 25-hydroxyvitamin D concentrations were negatively associated with kidney function. IR appears in the early stage of kidney dysfunction, and both serum 25(OH)D concentrations and kidney function are negatively associated with IR. Clinicians should maintain appropriate serum 25(OH)D concentrations and doses of vitamin D supplements for different populations. The underlying mechanism of these associations still needs more research, especially the negative association between serum 25(OH)D concentrations and kidney function.

Targeted regulation of Rell2 by microRNA-18a is implicated in the anti-metastatic effect of polyphyllin VI in breast cancer cells.

Polyphyllin VI (PP-VI) is one of the major saponins present in Paris polyphylla Sm., a medicinal plant primarily used for cancer treatment in China and India. However, its anti-metastatic activity remains largely unknown. The current study thus investigated the anti-metastatic activity of PP-VI in mouse mammary carcinoma 4T1 and human breast cancer MDA-MB-231 cells. The anti-metastatic effect of PP-VI was investigated at a sub-cytotoxic dose in migration and invasion assays in vitro. Experimental metastasis mouse model was used to examine the anti-metastatic effect of PP-VI in vivo. Additionally, target prediction, real-time PCR, Western blotting and luciferase assay were performed to identify the target gene of a pro-metastatic microRNA, miR-18a in 4T1 cells. The effect of PP-VI on the identified target of miR-18a was further investigated. The results showed that PP-VI impaired the viability of 4T1 and MDA-MB-231 cells. Moreover, when applied at a sub-cytotoxic dose, PP-VI suppressed the metastatic potential of 4T1 and MDA-MB-231 cells. Receptor expressed in lymphoid tissue (RELT)-like 2 (Rell2) was identified as a direct target of miR-18a with anti-metastatic functions in 4T1 and MDA-MB-231 cells. PP-VI treatment resulted in increased expression of Rell2 and decreased level of miR-18a in 4T1 and MDA-MB-231 cells. PP-VI treatment also attenuated miR-18a mimic or Rell2 siRNA-augmented migration of MDA-MB-231 cells. The current work thus demonstrates for the first time that targeted regulation of Rell2 by miR-18a is in part implicated in the anti-metastatic effect of PP-VI in breast cancer cells, providing novel pharmacological insights into the anti-cancer effect of PP-VI.

Panax notoginseng saponins attenuate lung cancer growth in part through modulating the level of Met/miR-222 axis.

ETHNOPHARMACOLOGICAL RELEVANCE: Panax notoginseng saponins (PNS) are the major chemical constituents of Panax notoginseng (Burkill) F.H. Chen (Araliaceae), a medicinal herb extensively used in China for the treatment of various diseases including cancer. PNS have been reported to contribute to the therapeutic effects of Panax notoginseng in disease conditions including lung cancer. AIM OF THE STUDY: The current study aims to further understand the molecular mechanisms implicated in the pharmacological activities of PNS in attenuating lung cancer growth. MATERIALS AND METHODS: Lewis lung carcinoma (LLC) cell line was employed and the impact of PNS treatment on the viability of LLC cells was first examined in vitro. The tumor-suppressive effect of PNS was further validated in vivo by assessing the tumor growth in BALB/c mice inoculated with LLC cells. Whole genome microarray and real-time PCR analyses were performed to examine and verify altered expression of genes associated with PNS treatment. Real-time PCR and western blotting analyses were also carried out to investigate the implication of microRNA (miRNA)-mediated gene expression regulation in the anti-tumor activity of PNS. RESULTS: PNS treatment resulted in selective impairment of the survival of LLC cells. Furthermore, PNS treatment led to attenuated growth of tumors derived from inoculated LLC cells in mice. Bioinformatic analyses of gene expression profiles revealed that multiple pathways associated with tumorigenesis were significantly modulated by PNS treatment in vivo. The expression of an array of genes promoting tumorigenesis and progression including Hgf, Met, Notch3, Scd1, Epas1, Col1a1, Raf1, Braf1 and CDK6 was significantly decreased by PNS treatment, whereas the expression of tumor suppressive Rxrg was significantly increased as a result of PNS treatment. The level of miR-222, a miRNA regulated by Met, was significantly decreased by PNS treatment. The expression of tumor suppressor p27 and PTEN, miR-222 target genes, was significantly increased by PNS treatment. CONCLUSION: Out work here presented novel evidence demonstrating that multiple mechanisms were implicated in the anti-tumor effects of PNS in lung cancer models. Particularly, PNS treatment significantly modulated the level of Met/miR-222 axis in LLC cells. Increased understanding of the anti-tumor mechanisms of PNS may provide further experimental evidence to help optimize the therapeutic modalities for the treatment of lung cancer and other types of cancer.

Shexiang Tongxin dropping pill attenuates atherosclerotic lesions in ApoE deficient mouse model.

ETHNOPHARMACOLOGICAL RELEVANCE: Shexiang Tongxin dropping pill (STDP) is a formulation of Traditional Chinese Medicine mainly used for clinical treatment of stable angina pectoris in China. AIM OF THE STUDY: To investigate the effects and mechanisms of STDP treatment on atherosclerosis. MATERIALS AND METHODS: ApoE deficient (ApoE(-/-)) mice were utilized to evaluate the effect of STDP treatment (30 mg/kg/day) on atherosclerotic lesions. Histopathological features of atherosclerotic lesions, serum levels of lipid proteins, parameters of oxidative stress and pro-inflammatory cytokines were measured by H&E staining, Masson's trichrome staining and ELISA, respectively. Real-time PCR analyses were performed to examine the aortic expression of atherosclerosis-associated microRNAs. RESULTS: The STDP treatment resulted in attenuated atherosclerotic lesion manifested by reduced lipid deposition, fibrosis and oxidative stress. It also led to increase in serum levels of GSH and SOD, decrease in MDA, decrease in CHO, TG, LDL, ox-LDL and increase in HDL, respectively. Additionally, the levels of pro-inflammatory cytokines including IL-2, IL-6, TNF-α and γ-IFN were markedly reduced by STDP treatment. Furthermore, STDP treatment was associated with a significant reduction in the aortic expression of miR-21a, miR-132, miR-126a, miR-155 and increased expression of miR-20a. CONCLUSION: Our results demonstrated for the first time that STDP attenuated atherosclerotic lesions in ApoE(-/-) mouse model. Moreover, STDP treatment exhibited multi-targeting effects on pathological, biochemical and molecular aspects of atherosclerosis implicating lipid regulation, fibrosis, inflammation and oxidative stress. Findings from the current study warrant further evaluation of the clinical application of STDP in atherosclerosis treatment.

Bidirectional regulation of angiogenesis and miR-18a expression by PNS in the mouse model of tumor complicated by myocardial ischemia.

BACKGROUND: Panax Notoginseng Saponins (PNS) is the major class of active constituents of notoginseng, a natural product extensively used as a therapeutic agent in China. Tumor when accompanied by cardiovascular disorders poses a greater challenge for clinical management given the paradoxical involvement of angiogenesis, therefore gaining increased research attention. This study aim to investigate effects of PNS and its activity components in the mouse model of tumor complicated with myocardial ischemia. METHODS: Tumor complexed with myocardial ischemia mouse model was first established, which was followed by histological and immunohistochemistry examination to assess the effect of indicated treatments on tumor, myocardial ischemia and tissue specific angiogenesis. MicroRNA (miRNA) profiling was further carried out to identify potential miRNA regulators that might mechanistically underline the therapeutic effects of PNS in this complex model. RESULTS: PNS and its major activity components Rg1, Rb1 and R1 suppressed tumor growth and simultaneously attenuated myocardial ischemia. PNS treatment led to decreased expression of CD34 and vWF in tumor and increased expression of these vascular markers in heart. PNS treatment resulted in reduced expression of miR-18a in tumor and upregulated expression of miR-18a in heart. CONCLUSIONS: Our data demonstrated for the first time that PNS exerts tissue specific regulatory effects on angiogenesis in part through modulating the expression of miR-18a, which could be responsible for its bidirectional effect on complex disease conditions where paradoxical angiogenesis is implicated. Therefore, our study provides experimental evidence warranting evaluation of PNS and related bioactive component as a rational therapy for complex disease conditions including co-manifestation of cancer and ischemic cardiovascular disease.

Panax notoginseng saponins (PNS) inhibits breast cancer metastasis.

ETHNOPHARMACOLOGICAL RELEVANCE: Panax notoginseng (Burkill) F.H. Chen (Araliaceae) has been extensively used as a therapeutic agent to treat a variety of diseases. Panax notoginseng saponins (PNS) consist of major therapeutically active components of Panax notoginseng. PNS inhibit the growth of a variety of tumor cells in vitro and in vivo. The aim of the study is to investigate the effects and underlying mechanisms of PNS on breast cancer metastasis. MATERIALS AND METHODS: 4T1 cell, a highly metastatic mouse breast carcinoma cell line, was utilized for in vitro and in vivo assays. In vitro assays were first performed to examine the effects of PNS on 4T1 cell viability, migration and invasion, respectively. Real-time PCR analyses were also performed to examine the effects of PNS on the expression of genes associated with tumor metastasis. The effect of PNS on 4T1 tumor cell metastasis was further assessed in spontaneous and experimental metastasis models in vivo. RESULTS: PNS treatment exhibited a dose-dependent effect on impairing 4T1 cell viability in vitro. However, when examined at a lower dose that did not affect cell viability, the migration and invasion of 4T1 cell was remarkably inhibited in vitro. Meanwhile, PNS treatment led to upregulated expression of genes known to inhibit metastasis and downregulated expression of genes promoting metastasis in cultured 4T1 cells. These results suggested a selective effect of PNS on 4T1 migration and invasion. This hypothesis was further addressed in 4T1 metastasis models in vivo. The results showed that the lung metastasis was significantly inhibited by PNS treatment in both spontaneous and experimental metastasis models. CONCLUSION: Taken together, our results demonstrated an inhibitory effect of PNS on 4T1 tumor metastasis, warranting further evaluation of PNS as a therapeutic agent for treating breast cancer metastasis.