NMR Studies of the Interactions between Sialyllactoses and the Polysialytransferase Domain for Polysialylation Inhibition.

It is known that sialyllactose (SL) in mammalians is a major source of sialic acid (Sia), which can further form cytidine monophosphate sialic acid (CMP-Sia), and the final product is polysialic acid (polySia) using polysialyltransferases (polySTs) on the neural cell adhesion molecule (NCAM). This process is called NCAM polysialylation. The overexpression of polysialylation is strongly related to cancer cell migration, invasion, and metastasis. In order to inhibit the overexpression of polysialylation, in this study, SL was selected as an inhibitor to test whether polysialylation could be inhibited. Our results suggest that the interactions between the polysialyltransferase domain (PSTD) in polyST and CMP-Siaand the PSTD and polySia could be inhibited when the 3'-sialyllactose (3'-SL) or 6'-sialyllactose (6'-SL) concentration is about 0.5 mM or 6'-SL and 3 mM, respectively. The results also show that SLs (particularly for 3'-SL) are the ideal inhibitors compared with another two inhibitors, low-molecular-weight heparin (LMWH) and cytidine monophosphate (CMP), because 3'-SL can not only be used to inhibit NCAM polysialylation, but is also one of the best supplements for infant formula and the gut health system.

EGR1 transcriptionally regulates SVEP1 to promote proliferation and migration in human coronary artery smooth muscle cells.

A low-frequency variant of sushi, von Willebrand factor type A, EGF, and pentraxin domain-containing protein 1 (SVEP1) is associated with the risk of coronary artery disease, as determined by a genome-wide association study. SVEP1 induces vascular smooth muscle cell proliferation and an inflammatory phenotype to promote atherosclerosis. In the present study, qRT‒PCR demonstrated that the mRNA expression of SVEP1 was significantly increased in atherosclerotic plaques compared to normal tissues. Bioinformatics revealed that EGR1 was a transcription factor for SVEP1. The results of the luciferase reporter assay, siRNA interference or overexpression assay, mutational analysis and ChIP confirmed that EGR1 positively regulated the transcriptional activity of SVEP1 by directly binding to its promoter. EGR1 promoted human coronary artery smooth muscle cell (HCASMC) proliferation and migration via SVEP1 in response to oxidized low-density lipoprotein (ox-LDL) treatment. Moreover, the expression level of EGR1 was increased in atherosclerotic plaques and showed a strong linear correlation with the expression of SVEP1. Our findings indicated that EGR1 binding to the promoter region drive SVEP1 transcription to promote HCASMC proliferation and migration.

The Bifunctional Effects of Lactoferrin (LFcinB11) in Inhibiting Neural Cell Adhesive Molecule (NCAM) Polysialylation and the Release of Neutrophil Extracellular Traps (NETs).

The expression of polysialic acid (polySia) on the neuronal cell adhesion molecule (NCAM) is called NCAM-polysialylation, which is strongly related to the migration and invasion of tumor cells and aggressive clinical status. Thus, it is important to select a proper drug to block tumor cell migration during clinical treatment. In this study, we proposed that lactoferrin (LFcinB11) may be a better candidate for inhibiting NCAM polysialylation when compared with CMP and low-molecular-weight heparin (LMWH), which were determined based on our NMR studies. Furthermore, neutrophil extracellular traps (NETs) represent the most dramatic stage in the cell death process, and the release of NETs is related to the pathogenesis of autoimmune and inflammatory disorders, with proposed involvement in glomerulonephritis, chronic lung disease, sepsis, and vascular disorders. In this study, the molecular mechanisms involved in the inhibition of NET release using LFcinB11 as an inhibitor were also determined. Based on these results, LFcinB11 is proposed as being a bifunctional inhibitor for inhibiting both NCAM polysialylation and the release of NETs.

The NMR studies of CMP inhibition of polysialylation.

The overexpression of polysialic acid (polySia) on neural cell adhesion molecules (NCAM) promotes hypersialylation, and thus benefits cancer cell migration and invasion. It has been proposed that the binding between the polysialyltransferase domain (PSTD) and CMP-Sia needs to be inhibited in order to block the effects of hypersialylation. In this study, CMP was confirmed to be a competitive inhibitor of polysialyltransferases (polySTs) in the presence of CMP-Sia and triSia (oligosialic acid trimer) based on the interactional features between molecules. The further NMR analysis suggested that polysialylation could be partially inhibited when CMP-Sia and polySia co-exist in solution. In addition, an unexpecting finding is that CMP-Sia plays a role in reducing the gathering extent of polySia chains on the PSTD, and may benefit for the inhibition of polysialylation. The findings in this study may provide new insight into the optimal design of the drug and inhibitor for cancer treatment.

Transcription factor FOXC1 positively regulates SFRP1 expression in androgenetic alopecia.

Androgenetic alopecia (AGA) is the most common type of hair loss dysfunction. Secreted frizzled related protein 1 (SFRP1) is found to be associated with hair loss, but its role in AGA and the regulation mechanism of its transcription level is unclear. The aim of our study is to explore the expression of SFRP1 in AGA samples and its transcriptional mechanism. Male frontal and occipital scalp hair follicles from AGA patients were collected, and human dermal papilla cells (DPCs) were isolated and cultured. SFRP1 gene was cloned and constructed into recombinant plasmids to perform dual-luciferase reporter assay. Transcription factor binding sites were predicted through the Jaspar website and further confirmed by the chromatin immunoprecipitation (ChIP) assay. Expression of genes in DPCs was determined by immunofluorescence (IF) staining, quantitative real-time PCR (qRT-PCR) and western blotting. Our findings showed that SFRP1 was highly expressed in DPCs of AGA patients. The core promoter region of SFRP1 was from -100 to +50 bp and was found to be positively regulated by forkhead box C1 (FOXC1), a transcription factor related to hair growth, both at mRNA and protein level in DPCs. Our study suggests that FOXC1 plays an important role in regulating SFRP1 transcription, which may provide new insights into the development of therapeutic strategies for the treatment of AGA.

The Graphical Studies of the Major Molecular Interactions for Neural Cell Adhesion Molecule (NCAM) Polysialylation by Incorporating Wenxiang Diagram into NMR Spectroscopy.

Polysialylation is a process of polysialic acid (polySia) addition to neural cell adhesion molecule (NCAM), which is associated with tumor cell migration and progression in many metastatic cancers and neurocognition. Polysialylation can be catalyzed by two highly homologous mammalian polysialyltransferases (polySTs), ST8Sia II (STX) and ST8Sia IV (PST). It has been proposed that two polybasic domains, polybasic region (PBR) and polysialyltransferase domain (PSTD) in polySTs, are possible binding sites for the intermolecular interactions of polyST-NCAM and polyST-polySia, respectively, as well as the intramolecular interaction of PSTD-PBR. In this study, Chou's wenxiang diagrams of the PSTD and PBR are used to determine the key amino acids of these intermolecular and intramolecular interactions, and thus it may be helpful for the identification of the crucial amino acids in the polyST and for the understanding of the molecular mechanism of NCAM polysialylation by incorporating the wenxiang diagram and molecular modeling into NMR spectroscopy.

Exosome-mediated pyroptosis of miR-93-TXNIP-NLRP3 leads to functional difference between M1 and M2 macrophages in sepsis-induced acute kidney injury.

Sepsis is a systemic inflammatory response syndrome caused by infection, resulting in organ dysfunction. Sepsis-induced acute kidney injury (AKI) is one of the most common potential complications. Increasing reports have shown that M1 and M2 macrophages both take part in the progress of AKI by influencing the level of inflammatory factors and the cell death, including pyroptosis. However, whether M1 and M2 macrophages regulate AKI by secreting exosome remains unknown. In the present study, we isolated the exosomes from M1 and M2 macrophages and used Western blot and enzyme-linked immunosorbent assay (ELISA) to investigate the effect of M1 and M2 exosomes on cell pyroptosis. miRNA sequencing was used to identify the different miRNA in M1 and M2 exosomes. Luciferase reporter assay was used to verify the target gene of miRNA. We confirmed that exosomes excreted by macrophages regulated cell pyroptosis in vitro by using Western blot and ELISA. miRNA sequencing revealed the differentially expressed level of miRNAs in M1 and M2 exosomes, among which miR-93-5p was involved in the regulation of pyroptosis. By using bioinformatics predictions and luciferase reporter assay, we found that thioredoxin-interacting protein (TXNIP) was a direct target of miR-93-5p. Further in vitro and in vivo experiments indicated that exosomal miR-93-5p regulated the TXNIP directly to influence the pyroptosis in renal epithelial cells, which explained the functional difference between different phenotypes of macrophages. This study might provide new targets for the treatment of sepsis-induced AKI.

Long non-coding RNA MALAT1 targeting STING transcription promotes bronchopulmonary dysplasia through regulation of CREB.

Bronchopulmonary dysplasia (BPD) is a severe complication of preterm infants characterized by increased alveolarization and inflammation. Premature exposure to hyperoxia is believed to be a key contributor to the pathogenesis of BPD. No effective preventive or therapeutic agents have been created. Stimulator of interferon gene (STING) is associated with inflammation and apoptosis in various lung diseases. Long non-coding RNA MALAT1 has been reported to be involved in BPD. However, how MALAT1 regulates STING expression remains unknown. In this study, we assessed that STING and MALAT1 were up-regulated in the lung tissue from BPD neonates, hyperoxia-based rat models and lung epithelial cell lines. Then, using the flow cytometry and cell proliferation assay, we found that down-regulating of STING or MALAT1 inhibited the apoptosis and promoted the proliferation of hyperoxia-treated cells. Subsequently, qRT-PCR, Western blotting and dual-luciferase reporter assays showed that suppressing MALAT1 decreased the expression and promoter activity of STING. Moreover, transcription factor CREB showed its regulatory role in the transcription of STING via a chromatin immunoprecipitation. In conclusion, MALAT1 interacts with CREB to regulate STING transcription in BPD neonates. STING, CREB and MALAT1 may be promising therapeutic targets in the prevention and treatment of BPD.

Molecular Interactions of the Polysialytransferase Domain (PSTD) in ST8Sia IV with CMP-Sialic Acid and Polysialic Acid Required for Polysialylation of the Neural Cell Adhesion Molecule Proteins: An NMR Study.

Polysialic acid (polySia) is an unusual glycan that posttranslational modifies neural cell adhesion molecule (NCAM) proteins in mammalian cells. The up-regulated expression of polySia-NCAM is associated with tumor progression in many metastatic human cancers and in neurocognitive processes. Two members of the ST8Sia family of α2,8-polysialyltransferases (polySTs), ST8Sia II (STX) and ST8Sia IV (PST) both catalyze synthesis of polySia when activated cytidine monophosphate(CMP)-Sialic acid (CMP-Sia) is translocate into the lumen of the Golgi apparatus. Two key polybasic domains in the polySTs, the polybasic region (PBR) and the polysialyltransferase domain (PSTD) areessential forpolysialylation of the NCAM proteins. However, the precise molecular details to describe the interactions required for polysialylation remain unknown. In this study, we hypothesize that PSTD interacts with both CMP-Sia and polySia to catalyze polysialylation of the NCAM proteins. To test this hypothesis, we synthesized a 35-amino acid-PSTD peptide derived from the ST8Sia IV gene sequence and used it to study its interaction with CMP-Sia, and polySia. Our results showed for the PSTD-CMP-Sia interaction,the largest chemical-shift perturbations (CSP) were in amino acid residues V251 to A254 in the short H1 helix, located near the N-terminus of PSTD. However, larger CSP values for the PSTD-polySia interaction were observed in amino acid residues R259 to T270 in the long H2 helix. These differences suggest that CMP-Sia preferentially binds to the domain between the short H1 helix and the longer H2 helix. In contrast, polySia was principally bound to the long H2 helix of PSTD. For the PSTD-polySia interaction, a significant decrease in peak intensity was observed in the 20 amino acid residues located between the N-and C-termini of the long H2 helix in PSTD, suggesting a slower motion in these residues when polySia bound to PSTD. Specific features of the interactions between PSTD-CMP-Sia, and PSTD-polySia were further confirmed by comparing their 800 MHz-derived HSQC spectra with that of PSTD-Sia, PSTD-TriSia (DP 3) and PSTD-polySia. Based on the interactions between PSTD-CMP-Sia, PSTD-polySia, PBR-NCAM and PSTD-PBR, these findingsprovide a greater understanding of the molecular mechanisms underlying polySia-NCAM polysialylation, and thus provides a new perspective for translational pharmacological applications and development by targeting the two polysialyltransferases.

miR-939-5p decreases the enrichment of RNA polymerase II in the promoter region of CD2AP involved in nephrotic syndrome.

The expression changes of CD2-associated protein (CD2AP) can lead to kidney diseases with proteinuria, including nephrotic syndrome (NS). A recent study reported that miRNAs may be important transcriptional regulators. In this study, we found increased expression of miR-939-5p and decreased expression of CD2AP in the peripheral blood of patients with NS. However, miR-939-5p did not show a regulatory effect on the 3'-untranslated region of CD2AP. The expression levels of specific protein 1 and adenovirus E2 promoter-binding factor 1, important transcription regulators in the promoter region of CD2AP, were also not affected by microRNA (miR)-939-5p. We confirmed that miR-939-5p is in the nucleus by fluorescent in situ hybridization and cytoplasmic separation polymerase chain reaction. The promoter plasmid and miR-939-5p were cotransfected into HEK-293 cells, and the luciferase reporter gene assay was used to analyze the promoter activity. We found that miR-939-5p binds to a specific sequence in the CD2AP promoter. miR-939-5p was confirmed to reduce the recruitment of RNA polymerase II to the CD2AP promoter region by chromatin immunoprecipitation. These findings improve our understanding of the mechanism of miR-939-5p in NS and provide potential molecular therapeutic targets for NS.

STING positively regulates human ORMDL3 expression through TBK1-IRF3-STAT6 complex mediation.

Orosomucoid 1-like protein 3 (ORMDL3) is an asthma candidate gene associated with virus-triggered recurrent wheeze. Stimulator of interferon gene (STING) controls TLR-independent cytosolic responses to viruses. However, the association of STING with ORMDL3 is unclear. Here, we have shown that ORMDL3 expression shows a linear correlation with STING in recurrent wheeze patients. In elucidating the molecular mechanisms of the ORMDL3-STING relationship, we found that STING promoted the transcriptional activity of ORMDL3, which was significantly associated with increased levels of interferon regulatory factor 3 (IRF3) and signal transducer and activator of transcription 6 (STAT6). Further study showed that via activation of TANK binding kinase 1 (TBK1), STING enhanced the phosphorylation and binding of IRF3 and STAT6, which upregulated ORMDL3 by binding to the promoter. Our results showed that STING positively regulated ORMDL3 through the TBK1-IRF3-STAT6 complex.

Methylation status of ORMDL3 regulates cytokine production and p-ERK/MMP9 pathway expression.

Orosomucoid like-3 (ORMDL3) has been identified to be associated with the development of asthma according to previous studies. However, the definite role of ORMDL3 in the pathogenesis of asthma remains unclear. In this study, we found ORMDL3 was highly expressed in PBMC specimens from childhood asthma patients. Cytokines production and p-ERK/MMP-9 pathway expression was also increased in childhood asthma patients compared with controls. In addition, ORMDL3 overexpression induced IL-6 and IL-8 release and activated p-ERK/MMP-9 pathway in vitro. Increased ORMDL3 expression was observed after treated with 5-Aza-CdR. 5-Aza-CdR decreased the percentage of the CpG island in the ORMDL3 promoter region and increased its promoter activity. In addition, 5-Aza-CdR significantly increased IL-6 and IL-8 levels in NHBE cells while there was no obvious alteration after knocking down ORMDL3. Knockdown of ORMDL3 also significantly decreased the expression of p-ERK/MMP-9 pathway in the presence or absence of 5-Aza-CdR. In conclusion, our study provided novel evidence for the association between ORMDL3 and asthma-associated cytokines. Moreover, DNA methylation plays an important role in ORMDL3-mediated increased IL-6 and IL-8 levels and p-ERK/MMP-9 pathway expression.

Cytotoxic triterpenoid saponins from the defatted seeds of Camellia oleifera Abel.

Five new oleanane-type triterpenoid saponins, oleiferasaponins D1-D5 (1-5), were isolated from the defatted seeds of Camellia oleifera Abel. Their structures were elucidated by spectroscopic and chemical methods. The cytotoxic activities of compounds 1-5 were evaluated against five human tumor cell lines (HCT-116, HepG2, BGC-823, NCI-H1650, and A2780). Compounds 1-2 exhibited cytotoxic activity against five human cancer cell lines, with IC50 values ranging from 3.31 to 10.23 µM. Compounds 3-5 showed moderate cytotoxic activities toward the tested cell lines.

All-trans retinoic acid upregulates the expression of ciliary neurotrophic factor in retinal pigment epithelial cells.

Retinopathy of prematurity, a leading cause of visual impairment in low birth-weight infants, remains a crucial therapeutic challenge. Ciliary neurotrophic factor (CNTF) is a promyelinating trophic factor that promotes rod and cone photoreceptor survival and cone outer segment regeneration in the degenerating retina. Ciliary neurotrophic factor expression is regulated by many factors such as all-trans retinoic acid (ATRA). In this study, we found that ATRA increased CNTF expression in mouse retinal pigment epithelial (RPE) cells in a dose- and time-dependent manner, and PKA signaling pathway is necessary for ATRA-induced CNTF upregulation. Furthermore, we showed that ATRA promoted CNTF expression through CREB binding to its promoter region. In addition, CNTF levels were decreased in serum of retinopathy of prematurity children and in retinal tissue of oxygen-induced retinopathy mice. In mouse RPE cells cultured with high oxygen, CNTF expression and secretion were decreased, but could be recovered after treatment with ATRA. In conclusion, our data suggest that ATRA administration upregulates CNTF expression in RPE cells.

[A retrospective analysis of 6 children with Duchenne muscular dystrophy].

OBJECTIVE: To analyze the clinical features of 6 children with Duchenne muscular dystrophy (DMD) and review related literature, and to provide a basis for early diagnosis and effective treatment of this disease. METHODS: A retrospective analysis was performed on the clinical data of 6 children with DMD who were admitted to the First Affiliated Hospital of Nanjing Medical University from January 2010 to October 2015. RESULTS: All the 6 cases were boys without a family history of DMD, and the age of diagnosis of DMD was 1.2-11.5 years. All patients had insidious onset and increases in alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, α-hydroxybutyrate dehydrogenase, creatine kinase (CK), and creatine kinase-MB, particularly CK, which was 3.3-107.2 times the normal level. Their gene detection results all showed DMD gene mutation. The gene detection results of two children's mothers showed that they carried the same mutant gene. The muscle biopsy in one case showed that the pathological changes confirmed the diagnosis of DMD. The level of CK in one case declined by 77.0% 5 days after umbilical cord blood mesenchymal stem cell transplantation. CONCLUSIONS: For boys with abnormal serum enzyme levels and motor function, DMD should be highly suspected. It should be confirmed by CK and DMD gene detection as soon as possible. And the progression of the disease could be delayed by early intervention for protecting the remaining normal muscle fibers.

MicroRNA-939 down-regulates CD2-associated protein by targeting promoter in HEK-293T cells.

CD2-associated protein (CD2AP) serves as a slit diaphragm (SD) protein and plays essential roles in maintaining podocyte integrity and reducing proteinuria. MicroRNAs (miRNAs) are novel regulators of gene expression. Podocyte-specific loss of miRNAs would lead to significant proteinuria. Here, we report new evidence in which miRNAs may function to suppress CD2AP expression through a transcriptional way. By scanning human CD2AP promoter in silico for sequences complementary to known miRNAs, we chose miR-939, miR-148b*, miR-191*, miR-638 as four candidates and transfected them into HEK-293T cells. Dual-luciferase reporter assay identified that only miR-939 significantly reduced the relative luciferase activity of CD2AP promoter region. Further analysis confirmed that the mRNA and protein expressions of CD2AP were also down-regulated by miR-939. In conclusion, we have identified that miR-939 targets CD2AP promoter sequences and suppresses its gene expression. These findings suggest that miRNAs may mediate podocyte injury via reducing the expression of the SD proteins, such as CD2AP.

Two new triterpenoids from Callicarpa kwangtungensis.

Two new triterpenoids, 2α,3ß,16α,19α,23-pentahydroxyolean-12-en-28-oic acid (1) and 2α,3α,11α,21α,23-pentahydroxyurs-12-en-28-oic acid (2), were isolated from the aerial parts of Callicarpa kwangtungensis. Their structures were elucidated by 1D and 2D analyses, as well as MS and IR spectra.

Four New Triterpenoids from Callicarpa kwangtungensis.

Four new triterpenoids which were identifed as 2α,3ß,6ß,19α-tetrahydroxy- oleanolic acid 28-O-ß-D-glucopyranoside (1), 2-O-ß-D-glucopyranosyloxy-3α,19α-di-hydroxyoleanolic acid (2), 2-O-ß-D-glucopyranosyloxy-3α,19α-dihydroxyursolic acid (3), 2α,3α,6ß,19α-tetrahydroxyursolic acid 28-O-ß-D-glucopyranoside (4), were isolated from the aerial parts of Callicarpa kwangtungensis together with three known triterpenoids identified as 2α,3ß,21ß-trihydroxyursolic acid 28-O-ß-D-glucopyranoside (5), 2α,3α,19α,23-tetrahydroxyoleanolic acid 28-O-ß-D-glucopyranoside (6), 2α,3α,19α,23-tetrahydroxyursolic acid 28-O-ß-D-glucopyranoside (7). Their structures were elucidated by the combination of mass spectrometry (MS), one and two-dimensional NMR experiments.

[Ethyl Acetate-Soluble Chemical Constituents from Callicarpa kwangtungensis (II)].

OBJECTIVE: To study the ethyl acetate-soluble chemical constituents of Callicarpa kwangtungensis. METHODS: The chemical constituents were isolated by column chromatography on silica gel, Sephadex LH-20 and MPLC. Their chemical structures were elucidated on the basis of special analysis. RESULTS: Eleven compounds were isolated from the ethyl acetate-soluble part of Callicarpa kwangtungensis, whose structures were elucidated as 4-methoxybenzoic acid (1), 3,4-dihydroxybenzoic acid (2), 4-hydroxy cinnamic acid(3), phenyl-ß-D-glucopyranoside (4), 3,4,5-trimethoxyphenyl-ß-D-glucopyranoside (5), 2α,3ß,22ß,23-tetrahydroxyursolic-12-en-28-oic acid (6), 2α,3ß,6ß,19α-tetrahydroxy-urs-12-en-28-O-ß-D-glucopyranoside (7), 2ß,3ß,6ß,16α-tetrahydroxy-olean-12-en-28-O-ß-D-glucopyranoside (8), (3S, 6E, 10R)-10-ß-D-glucopyranosyloxy-3,11-dihydroxy-3,7,11-trimethyldodeca-1,6-diene (9), icariside C5(10), and (2E, 6E)-10-ß-D-glucopyranosyl-1, 11-dihydroxy-3, 7, 11-trimethyldodeca-2,6-diene (11). CONCLUSION: Compounds 4 - 11are isolated from Callicarpa genus for the first time, compounds 1 - 3 are isolated from this plant for the first time.

[Chemical Constituents from Camellia oleifera Stem].

OBJECTIVE: To study the chemical constituents of stem of Camellia oleifera. METHODS: The chemical constituents were isolated and purified by column chromatography on silica gel, ODS, Sephadex LH-20 and MPLC. Their structures were elucidated on the basis of physicochemical properties and special analysis. RESULTS: Seven compounds were isolated from the stem of Camellia oleifera, whose structures were elucidated as (-) -pinoresinol (1), (-) -medioresinol (2), skullcapflavone II (3), betulinic acid (4), ursolic acid (5), 3-O-ß-D-glucopyranosyl- (1 --> 2) -ß-D-xylopyransoyl-(1 --> 3) -[ß-D-glucopyranosyl- (1 --> 2)] -ß-D-glucuronopyranosyl-22α-angeloyloxyolean-12-ene-15α,16α,28-triol (6) and oleanolic acid (7). CONCLUSION: Compounds 1 - 6 are isolated from this plant for the first time, and compounds 1 - 3 are isolated from this genus for the first time.