1.Polysaccharide Krestin Prevents Alzheimer's Disease-type Pathology and Cognitive Deficits by Enhancing Monocyte Amyloid-β Processing.
Si-Han CHEN ; Chen-Yang HE ; Ying-Ying SHEN ; Gui-Hua ZENG ; Ding-Yuan TIAN ; Yuan CHENG ; Man-Yu XU ; Dong-Yu FAN ; Cheng-Rong TAN ; An-Yu SHI ; Xian-Le BU ; Yan-Jiang WANG
Neuroscience Bulletin 2022;38(3):290-302
Deficits in the clearance of amyloid β protein (Aβ) by the peripheral system play a critical role in the pathogenesis of sporadic Alzheimer's disease (AD). Impaired uptake of Aβ by dysfunctional monocytes is deemed to be one of the major mechanisms underlying deficient peripheral Aβ clearance in AD. In the current study, flow cytometry and biochemical and behavioral techniques were applied to investigate the effects of polysaccharide krestin (PSK) on AD-related pathology in vitro and in vivo. We found that PSK, widely used in therapy for various cancers, has the potential to enhance Aβ uptake and intracellular processing by human monocytes in vitro. After administration of PSK by intraperitoneal injection, APP/PS1 mice performed better in behavioral tests, along with reduced Aβ deposition, neuroinflammation, neuronal loss, and tau hyperphosphorylation. These results suggest that PSK holds promise as a preventive agent for AD by strengthening the Aβ clearance by blood monocytes and alleviating AD-like pathology.
Alzheimer Disease/pathology*
;
Amyloid beta-Peptides/metabolism*
;
Amyloid beta-Protein Precursor/metabolism*
;
Animals
;
Cognition
;
Disease Models, Animal
;
Mice
;
Mice, Transgenic
;
Monocytes/pathology*
;
Polysaccharides/therapeutic use*
;
Proteoglycans
2.The role of tyrosine phosphatase Shp2 in spermatogonial differentiation and spermatocyte meiosis.
Yang LI ; Wen-Sheng LIU ; Jia YI ; Shuang-Bo KONG ; Jian-Cheng DING ; Yi-Nan ZHAO ; Ying-Pu TIAN ; Gen-Sheng FENG ; Chao-Jun LI ; Wen LIU ; Hai-Bin WANG ; Zhong-Xian LU
Asian Journal of Andrology 2020;22(1):79-87
The transition from spermatogonia to spermatocytes and the initiation of meiosis are key steps in spermatogenesis and are precisely regulated by a plethora of proteins. However, the underlying molecular mechanism remains largely unknown. Here, we report that Src homology domain tyrosine phosphatase 2 (Shp2; encoded by the protein tyrosine phosphatase, nonreceptor type 11 [Ptpn11] gene) is abundant in spermatogonia but markedly decreases in meiotic spermatocytes. Conditional knockout of Shp2 in spermatogonia in mice using stimulated by retinoic acid gene 8 (Stra8)-cre enhanced spermatogonial differentiation and disturbed the meiotic process. Depletion of Shp2 in spermatogonia caused many meiotic spermatocytes to die; moreover, the surviving spermatocytes reached the leptotene stage early at postnatal day 9 (PN9) and the pachytene stage at PN11-13. In preleptotene spermatocytes, Shp2 deletion disrupted the expression of meiotic genes, such as disrupted meiotic cDNA 1 (Dmc1), DNA repair recombinase rad51 (Rad51), and structural maintenance of chromosome 3 (Smc3), and these deficiencies interrupted spermatocyte meiosis. In GC-1 cells cultured in vitro, Shp2 knockdown suppressed the retinoic acid (RA)-induced phosphorylation of extracellular-regulated protein kinase (Erk) and protein kinase B (Akt/PKB) and the expression of target genes such as synaptonemal complex protein 3 (Sycp3) and Dmc1. Together, these data suggest that Shp2 plays a crucial role in spermatogenesis by governing the transition from spermatogonia to spermatocytes and by mediating meiotic progression through regulating gene transcription, thus providing a potential treatment target for male infertility.
Animals
;
Cell Cycle Proteins/genetics*
;
Cell Line
;
Cell Survival
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Chondroitin Sulfate Proteoglycans/genetics*
;
Chromosomal Proteins, Non-Histone/genetics*
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Gene Expression Regulation
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Gene Knockdown Techniques
;
Infertility, Male
;
Male
;
Meiosis/genetics*
;
Mice
;
Mice, Knockout
;
Mice, Transgenic
;
Phosphate-Binding Proteins/genetics*
;
Protein Tyrosine Phosphatase, Non-Receptor Type 11/genetics*
;
Rad51 Recombinase/genetics*
;
Real-Time Polymerase Chain Reaction
;
Spermatocytes/metabolism*
;
Spermatogenesis/genetics*
;
Spermatogonia/metabolism*
3.Mechanism of thermosensitive moxibustion on knee osteoarthritis in rabbit models.
Yong FU ; Shutao CHEN ; Jiaona MAO ; Yi PAN ; Chao HUANG ; Jun XIONG ; Chunchuan YAN ; Xiaodong HUANG ; Haifeng ZHANG
Chinese Acupuncture & Moxibustion 2018;38(3):291-296
OBJECTIVETo observe the impacts of thermosensitive moxibustion (TSM) on the expressions of nitric oxide (NO), typeⅠdisintegrin and metalloproteinase with thrombospondin motifs-4 (ADAMTS-4), typeⅡcollagen and proteoglycan (PG) in the rabbit models of knee osteoarthritis (KOA) and explore the mechanism of TSM on KOA.
METHODSA total of 42 Japanese long-eared male rabbits were divided into a blank group (6 rabbits), a model group (6 rabbits), a moxibustion group (24 rabbits) and a sham-operation group (6 rabbits) according to the random number table. In the blank group, the rabbits were fed normally. In the model and moxibustion groups, the papain injection was given to establish KOA models. The rabbits in the sham-operation group were treated with the intracavity injection of 0.9% NaCl solution. The rabbits were forced to move for 30 min every day, continuously for 15 days during modeling. At the end of modeling, in the moxibustion group, moxibusiton was applied at "Dubi" (ST 35), once a day, 40 min each time, for 14 days totally. According to the temperature changes during moxibustion, the rabbits were divided into a TSM group and a non-TSM group. 6 rabbits were collected randomly from the two groups. The usual feeding was given in the blank group, the model group and the sham-operation group, without any intervention. The body mass and behavioristics changes were observed in each group. At the end of treatment, the nitrate reduction method was adopted to determine NO expression in the serum. The real-time PCR was adopted to determine the expressions of ADAMTS-4, typeⅡcollagen and PG in the cartilage.
RESULTS① After modeling, compared with the blank group, the body mass was all reduced and the Lequesne MG score was increased in the model group, TSM group, non-TSM group and sham-operation group (<0.05, <0.01). After intervention, compared with the blank group, the body mass was decreased and the Lequesne MG score was increased in the model and sham-operation groups (<0.05, <0.01). Compared with the model group, the body mass was increased and the lequesne MG score was decreased in the TSM, non-TSM, and sham-operation groups (<0.05, <0.01). Compared with the non-TSM group, the body mass in the TSM group was increased remarkably (<0.05), but the difference in Lequesne MG score was not statistically significant (>0.05). ② After intervention, compared with the blank group, the expressions of NO and ADAMTS-4 were all increased and the expressions of typeⅡcollagen and PG were decreased in the model group, TSM group, non-TSM group and sham-operation group (<0.05, <0.01). Compared with the model group, the expressions of NO and ADAMTS-4 were all remarkably lower and the expressions of typeⅡcollagen and PG were increased in the TSM group, non-TSM group and sham-operation group (<0.05, <0.01). Compared with the non-TSM group, the expressions of NO and ADAMTS-4 were all remarkably lower and the expressions of typeⅡcollagen and PG were increased in the TSM group after intervention (all <0.05).
CONCLUSIONThe thermosensitive moxibustion alleviates the inflammatory reactions and protects the joint cartilage through inhibiting the expressions of NO and ADAMTS-4 to achieve the effects in the treatment of KOA.
ADAMTS4 Protein ; metabolism ; Animals ; Cartilage ; metabolism ; Collagen Type III ; metabolism ; Male ; Moxibustion ; Nitric Oxide ; blood ; Osteoarthritis, Knee ; therapy ; Proteoglycans ; metabolism ; Rabbits ; Random Allocation
4.Glycosylation of dentin matrix protein 1 is a novel key element for astrocyte maturation and BBB integrity.
Bo JING ; Chunxue ZHANG ; Xianjun LIU ; Liqiang ZHOU ; Jiping LIU ; Yinan YAO ; Juehua YU ; Yuteng WENG ; Min PAN ; Jie LIU ; Zuolin WANG ; Yao SUN ; Yi Eve SUN
Protein & Cell 2018;9(3):298-309
The blood-brain barrier (BBB) is a tight boundary formed between endothelial cells and astrocytes, which separates and protects brain from most pathogens as well as neural toxins in circulation. However, detailed molecular players involved in formation of BBB are not completely known. Dentin matrix protein 1 (DMP1)-proteoglycan (PG), which is known to be involved in mineralization of bones and dentin, is also expressed in soft tissues including brain with unknown functions. In the present study, we reported that DMP1-PG was expressed in brain astrocytes and enriched in BBB units. The only glycosylation site of DMP1 is serine89 (S89) in the N-terminal domain of the protein in mouse. Mutant mice with DMP1 point mutations changing S89 to glycine (S89G), which completely eradicated glycosylation of the protein, demonstrated severe BBB disruption. Another breed of DMP1 mutant mice, which lacked the C-terminal domain of DMP1, manifested normal BBB function. The polarity of S89G-DMP1 astrocytes was disrupted and cell-cell adhesion was loosened. Through a battery of analyses, we found that DMP1 glycosylation was critically required for astrocyte maturation both in vitro and in vivo. S89G-DMP1 mutant astrocytes failed to express aquaporin 4 and had reduced laminin and ZO1 expression, which resulted in disruption of BBB. Interestingly, overexpression of wild-type DMP1-PG in mouse brain driven by the nestin promoter elevated laminin and ZO1 expression beyond wild type levels and could effectively resisted intravenous mannitol-induced BBB reversible opening. Taken together, our study not only revealed a novel element, i.e., DMP1-PG, that regulated BBB formation, but also assigned a new function to DMP1-PG.
Animals
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Astrocytes
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cytology
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metabolism
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Blood-Brain Barrier
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cytology
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metabolism
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Cells, Cultured
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Extracellular Matrix Proteins
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genetics
;
metabolism
;
Female
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Glycosylation
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Male
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Mice
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Proteoglycans
;
metabolism
;
Reverse Transcriptase Polymerase Chain Reaction
5.Glucosamine Hydrochloride and N-Acetylglucosamine Influence the Response of Bovine Chondrocytes to TGF-β3 and IGF in Monolayer and Three-Dimensional Tissue Culture.
André Luiz A PIZZOLATTI ; Florian GAUDIG ; Daniel SEITZ ; Carlos R M ROESLER ; Gean Vitor SALMORIA
Tissue Engineering and Regenerative Medicine 2018;15(6):781-791
BACKGROUND: Glucosamine hydrochloride (GlcN·HCl) has been shown to inhibit cell growth and matrix synthesis, but not with N-acetyl-glucosamine (GlcNAc) supplementation. This effect might be related to an inhibition of critical growth factors (GF), or to a different metabolization of the two glucosamine derivatives. The aim of the present study was to evaluate the synergy between GlcN·HCl, GlcNAc, and GF on proliferation and cartilage matrix synthesis. METHOD: Bovine chondrocytes were cultivated in monolayers for 48 h and in three-dimensional (3D) chitosan scaffolds for 30 days in perfusion bioreactors. Serum-free (SF) medium was supplemented with either growth factors (GF) TGF-β (5 ng mL₋₁) and IGF-I (10 ng mL₋₁), GlcN·HCl or GlcNAc at 1mM each or both. Six groups were compared according to medium supplementation: (a) SF control; (b) SF + GlcN·HCl; (c) SF + GlcNAc; (d) SF + GF; (e) SF + GF + GlcN·HCl; and (f) SF + GF + GlcNAc. Cell proliferation, proteoglycan, collagen I (COL1), and collagen II (COL2) synthesis were evaluated. RESULTS: The two glucosamines showed opposite effects in monolayer culture: GlcN·HCl significantly reduced proliferation and GlcNAc significantly augmented cellular metabolism. In the 30 days 3D culture, the GlcN·HCl added to GF stimulated cell proliferation more than when compared to GF only, but the proteoglycan synthesis was smaller than GF. However, GlcNAc added to GF improved the cell proliferation and proteoglycan synthesis more than when compared to GF and GF/GlcN·HCl. The synthesis of COL1 and COL2 was observed in all groups containing GF. CONCLUSION: GlcN·HCl and GlcNAc increased cell growth and stimulated COL2 synthesis in long-time 3D culture. However, only GlcNAc added to GF improved proteoglycan synthesis.
Bioreactors
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Cartilage
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Cell Proliferation
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Chitosan
;
Chondrocytes*
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Collagen
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Glucosamine*
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Insulin-Like Growth Factor I
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Intercellular Signaling Peptides and Proteins
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Metabolism
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Methods
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Perfusion
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Proteoglycans
6.Inhibitory effect of andrographolide on angiogenesis induced by the supernatant from cultured tumor cells.
Xiaolan GUO ; Maozhou ZHAO ; Yuyin LIN ; Wensheng CHEN ; Shiwen WANG ; Jianwei DAI
Journal of Central South University(Medical Sciences) 2018;43(8):821-825
To determine the effect of andrographolide (Andro) on angiogenesis of human umbilical vein endothelial cells (HUVECs).
Methods: HUVECs were treated with different concentrations of Andro and the cell viability was detected with Cell Counting Kit-8 (CCK-8). HUVECs were treated with half lethal dose (IC50) of Andro. Matrigel was used to make capillary formation of HUVECs and the effect of Andro on capillary formation was evaluated by calculating the percentage of capillary formation. Moreover, the effects of Andro and the supernatant from cultured A549 tumor cells on capillary formation were evaluated by calculating the percentage of capillary formation. The effect of Andro on the expression of matrix metalloproteinase-9 (MMP-9) was determined with Western blot.
Results: The cell viability of HUVECs decreased with the increase of Andro concentrations. IC50 was 20 μmol/L. The capillary formation of HUVECs was inhibited when treated with 20 μmol/L Andro for 24 hours. Moreover, Andro was able to antagonize the promotion of the capillary formation induced by the supernatant from cultured tumor cells. Andro could suppress the expression of MMP-9 and antagonize the capillary formation.
Conclusion: Andro inhibits the capillary formation of HUVECs and can antagonize the promotion of angiogenesis induced by the supernatant from cultured tumor cells.
Capillaries
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drug effects
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Cell Survival
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Collagen
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Culture Media
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Diterpenes
;
pharmacology
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Drug Combinations
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Human Umbilical Vein Endothelial Cells
;
drug effects
;
Humans
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Laminin
;
Matrix Metalloproteinase 9
;
metabolism
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Neovascularization, Pathologic
;
enzymology
;
etiology
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prevention & control
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Proteoglycans
;
Tumor Cells, Cultured
7.Pamidronate Down-regulates Tumor Necrosis Factor-alpha Induced Matrix Metalloproteinases Expression in Human Intervertebral Disc Cells.
Young Mi KANG ; Seong Hwan HONG ; Jae Ho YANG ; Jin Cheol OH ; Jin Oh PARK ; Byung Ho LEE ; Sang Yoon LEE ; Hak Sun KIM ; Hwan Mo LEE ; Seong Hwan MOON
Journal of Bone Metabolism 2016;23(3):165-173
BACKGROUND: N-containing bisphosphonates (BPs), such as pamidronate and risedronate, can inhibit osteoclastic function and reduce osteoclast number by inducing apoptotic cell death in osteoclasts. The aim of this study is to demonstrate the effect of pamidronate, second generation nitrogen-containing BPs and to elucidate matrix metallo-proteinases (MMPs) mRNA expression under serum starvation and/or tumor necrosis factor alpha (TNF-α) stimulation on metabolism of intervertebral disc (IVD) cells in vitro. METHODS: Firstly, to test the effect of pamidronate on IVD cells in vitro, various concentrations (10⁻¹², 10⁻¹⁰, 10⁻⁸, and 10⁻⁶ M) of pamidronate were administered to IVD cells. Then DNA and proteoglycan synthesis were measured and messenger RNA (mRNA) expressions of type I collagen, type II collagen, and aggrecan were analyzed. Secondly, to elucidate the expression of MMPs mRNA in human IVD cells under the lower serum status, IVD cells were cultivated in full serum or 1% serum. Thirdly, to elucidate the expression of MMPs mRNA in IVD cells under the stimulation of 1% serum and TNF-α (10 ng/mL) In this study, IVD cells were cultivated in three dimensional alginate bead. RESULTS: Under the lower serum culture, IVD cells in alginate beads showed upregulation of MMP 2, 3, 9, 13 mRNA. The cells in lower serum and TNF-α also demonstrated upregulation of MMP-2, 3, 9, and 13 mRNA. The cells with various doses of pamidronate and lower serum and TNF-α were reveled partial down-regulation of MMPs. CONCLUSIONS: Pamidronate, N-containing second generation BPs, was safe in metabolism of IVD in vitro maintaining chondrogenic phenotype and matrix synthesis, and down-regulated TNF-α induced MMPs expression.
Aggrecans
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Cell Death
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Collagen
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Collagen Type I
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Collagen Type II
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Diphosphonates
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DNA
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Down-Regulation
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Humans*
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In Vitro Techniques
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Intervertebral Disc*
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Matrix Metalloproteinases*
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Metabolism
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Osteoclasts
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Phenotype
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Proteoglycans
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Risedronate Sodium
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RNA, Messenger
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Starvation
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Tumor Necrosis Factor-alpha*
;
Up-Regulation
8.Pro-angiogenic activity of notoginsenoside R1 in human umbilical vein endothelial cells in vitro and in a chemical-induced blood vessel loss model of zebrafish in vivo.
Bin-Rui YANG ; Si-Jia HONG ; Simon Ming-Yuen LEE ; Wei-Hong CONG ; Jian-Bo WAN ; Zhe-Rui ZHANG ; Qing-Wen ZHANG ; Yi ZHANG ; Yi-Tao WANG ; Zhi-Xiu LIN
Chinese journal of integrative medicine 2016;22(6):420-429
OBJECTIVEThis study aimed at investigating whether notoginsenoside R1 (R1), a unique saponin found in Panax notoginseng could promote angiogenic activity on human umbilical vein endothelial cells (HUVECs) and elucidate their potential molecular mechanisms. In addition, vascular restorative activities of R1 was assessed in a chemically-induced blood vessel loss model in zebrafish.
METHODSThe in vitro angiogenic effect of R1 was compared with other previously reported angiogenic saponins Rg1 and Re. The HUVECs proliferation in the presence of R1 was determined by cell proliferation kit II (XTT) assay. R1, Rg1 and Re-induced HUVECs invasion across polycarbonate membrane was stained with Hoechst-33342 and quantified microscopically. Tube formation assay using matrigelcoated wells was performed to evaluate the pro-angiogenic actions of R1. In order to understand the mechanism underlying the pro-angiogenic effect, various pathway inhibitors such as SU5416, wortmannin (wort) or L-Nω-nitro- L-arginine methyl ester hydrochloride (L-NAME), SH-6 were used to probe the possible involvement of signaling pathway in the R1 mediated HUVECs proliferation. In in vivo assays, zebrafish embryos at 21 hpf were pre-treated with vascular endothelial growth factor (VEGF) receptor kinase inhibitor II (VRI) for 3 h only and subsequently post-treated with R1 for 48 h, respectively. The intersegmental vessels (ISVs) in zebrafish were assessed for the restorative effect of R1 on defective blood vessels.
RESULTSR1 could stimulate the proliferation of HUVECs. In the chemoinvasion assay, R1 significantly increased the number of cross-membrane HUVECs. In addition, R1 markedly enhanced the tube formation ability of HUVECs. The proliferative effects of these saponins on HUVECs were effectively blocked by the addition of SU5416 (a VEGF-KDR/Flk-1 inhibitor). Similarly, pre-treatment with wort [a phosphatidylinositol 3-kinase (PI3K)-kinase inhibitor], L-NAME [an endothelial nitric oxide synthase (eNOS) inhibitor] or SH-6 (an Akt pathway inhibitor) significantly abrogated the R1 induced proliferation of HUVECs. In chemicallyinduced blood vessel loss model in zebrafish, R1 significantly rescue the damaged ISVs.
CONCLUSIONR1, similar to Rg1 and Re, had been showed pro-angiogenic action, possibly via the activation of the VEGF-KDR/Flk-1 and PI3K-Akt-eNOS signaling pathways. Our findings also shed light on intriguing pro-angiogenic effect of R1 under deficient angiogenesis condition in a pharmacologic-induced blood vessels loss model in zebrafish. The present study in vivo and in vitro provided scientific evidence to explain the ethnomedical use of Panax notoginseng in the treatment of cardiovascular diseases, traumatic injuries and wound healing.
Animals ; Blood Vessels ; pathology ; Cell Movement ; drug effects ; Cell Proliferation ; drug effects ; Collagen ; pharmacology ; Disease Models, Animal ; Drug Combinations ; Ginsenosides ; chemistry ; pharmacology ; Human Umbilical Vein Endothelial Cells ; cytology ; drug effects ; enzymology ; physiology ; Humans ; Laminin ; pharmacology ; Neovascularization, Physiologic ; drug effects ; Phosphatidylinositol 3-Kinases ; metabolism ; Protein Kinase Inhibitors ; pharmacology ; Proteoglycans ; pharmacology ; Proto-Oncogene Proteins c-akt ; metabolism ; Vascular Endothelial Growth Factor Receptor-2 ; metabolism ; Zebrafish
9.Effect of antibacterial peptide hCAP18/LL-37 on ovarian cancer microenvironment and the regulatory mechanism of its expression.
Qian LU ; Wenqiang QUAN ; Junlu WU ; Xian ZHANG ; Wei MA ; Li PANG ; Dong LI ; Email: 186LD@163.COM.
Chinese Journal of Oncology 2015;37(10):725-730
OBJECTIVETo investigate the effect of antibacterial peptide hCAP18/LL-37 on ovarian cancer microenvironment and the regulatory mechanism of its expression.
METHODSWe assessed the effect of macrophage-promoted ovarian cancer cells invasion using BioCoat Matrigel invasion chamber. The expressions of hCAP18/LL-37 and versican V1 were determined by real-time PCR and Western blot analysis. SKOV3 cells were transfected with shRNA plasmid to abrogate the expression of versican V1, and then the expression of hCAP18/LL-37 in macrophages and the invasiveness of SKOV3 cells were assayed.
RESULTSThe Matrigel invasion assay showed that after co-culture with macrophages for 4 days, the number of penetrated SKOV3 cells was 112.8±17.1/per high power field, significantly higher than that in the SKOV3 cells cultured alone (8.2±1.9/per high power field) (P<0.05). Addition of hCAP/LL-37 neutralizing antibody into the co-cultured macrophage-SKOV3 cells markedly inhibited the macrophage-promoted SKOV3 cells invasion. The penetrated SKOV3 cells was 22.2±5.6/per high power field, significantly lower than the 100.6±25.2/per high power field in the control macrophage- SKOV3 co-cultured cells (P<0.05). The expressions of hCAP18/LL-37 mRNA and protein in macrophages were remarkably enhanced upon co-culture with SKOV3 cells, but not changed in SKOV3 cells cultured alone. The expression and secretion of versican V1 in the ovarian cancer cells were also significantly increased after co-cultured with macrophages. Knockdown of versican V1 in SKOV3 cells by small interfering RNA significantly reduced the expression of hCAP18/LL-37 mRNA and protein in the macrophages, as well as decreased the invasiveness of SKOV3 cells (P<0.05).
CONCLUSIONSIn the cancer microenvironment, the macrophage-secreted hCAP18/LL-37 promote the invasiveness of ovarian cancer cells, and the hCAP18/LL-37 expression is regulated by versican V1 protein released by ovarian cancer cells.
Antimicrobial Cationic Peptides ; metabolism ; pharmacology ; Cell Line, Tumor ; Coculture Techniques ; Collagen ; Drug Combinations ; Female ; Humans ; Laminin ; Macrophages ; metabolism ; Neoplasm Invasiveness ; Neoplasm Proteins ; metabolism ; Ovarian Neoplasms ; metabolism ; pathology ; physiopathology ; Plasmids ; Proteoglycans ; RNA, Messenger ; metabolism ; RNA, Small Interfering ; Real-Time Polymerase Chain Reaction ; Transfection ; Tumor Microenvironment ; drug effects ; Versicans ; metabolism
10.From DCPD to NTCP: The long journey towards identifying a functional hepatitis B virus receptor.
Clinical and Molecular Hepatology 2015;21(3):193-199
Hepatitis B virus (HBV) is the prototype of hepatotropic DNA viruses (hepadnaviruses) infecting a wide range of human and non-human hosts. Previous studies with duck hepatitis B virus (DHBV) identified duck carboxypeptidase D (dCPD) as a host specific binding partner for full-length large envelope protein, and p120 as a binding partner for several truncated versions of the large envelope protein. p120 is the P protein of duck glycine decarboxylase (dGLDC) with restricted expression in DHBV infectible tissues. Several lines of evidence suggest the importance of dCPD, and especially p120, in productive DHBV infection, although neither dCPD nor p120 cDNA could confer susceptibility to DHBV infection in any cell line. Recently, sodium taurocholate cotransporting polypeptide (NTCP) has been identified as a binding partner for the N-terminus of HBV large envelope protein. Importantly, knock down and reconstitution experiments unequivocally demonstrated that NTCP is both necessary and sufficient for in vitro infection by HBV and hepatitis delta virus (HDV), an RNA virus using HBV envelope proteins for its transmission. What remains unclear is whether NTCP is the major HBV receptor in vivo. The fact that some HBV patients are homozygous with an NTCP mutation known to abolish its receptor function suggests the existence of NTCP-independent pathways of HBV entry. Also, NTCP very likely mediates just one step of the HBV entry process, with additional co-factors for productive HBV infection still to be discovered. NTCP offers a novel therapeutic target for the control of chronic HBV infection.
Animals
;
Carboxypeptidases/genetics/*metabolism
;
Gene Products, pol/genetics/metabolism
;
Heparan Sulfate Proteoglycans/metabolism
;
Hepatitis B virus/*physiology
;
Hepatocytes/metabolism/virology
;
Organic Anion Transporters, Sodium-Dependent/antagonists & inhibitors/genetics/metabolism
;
RNA Interference
;
Symporters/antagonists & inhibitors/genetics/metabolism
;
Viral Envelope Proteins/metabolism
;
Virus Internalization

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