Cellular spermine targets JAK signaling to restrain cytokine-mediated autoimmunity.

Prolonged activation of the type I interferon (IFN-I) pathway leads to autoimmune diseases such as systemic lupus erythematosus (SLE). Metabolic regulation of cytokine signaling is critical for cellular homeostasis. Through metabolomics analyses of IFN-ß-activated macrophages and an IFN-stimulated-response-element reporter screening, we identified spermine as a metabolite brake for Janus kinase (JAK) signaling. Spermine directly bound to the FERM and SH2 domains of JAK1 to impair JAK1-cytokine receptor interaction, thus broadly suppressing JAK1 phosphorylation triggered by cytokines IFN-I, IFN-II, interleukin (IL)-2, and IL-6. Peripheral blood mononuclear cells (PBMCs) from individuals with SLE showing decreased spermine concentrations exhibited enhanced IFN-I and lupus gene signatures. Spermine treatment attenuated autoimmune pathogenesis in SLE and psoriasis mice and reduced IFN-I signaling in monocytes from individuals with SLE. We synthesized a spermine derivative (spermine derivative 1 [SD1]) and showed that it had a potent immunosuppressive function. Our findings reveal spermine as a metabolic checkpoint for cellular homeostasis and a potential immunosuppressive molecule for controlling autoimmune disease.

A model of pregnancy-associated malaria for inducing adverse pregnancy outcomes in ICR mouse.

BACKGROUND: Based on understanding of placental pathological features and safe medication in pregnancy-associated malaria (PAM), establishment of a stable pregnant mouse infection model with Plasmodium was urgently needed. METHODS: ICR mice with vaginal plugs detected were randomly divided into post-pregnancy infection (Malaria+) and uninfected pregnancy (Malaria-) cohorts. Age-matched mice that had not been mated were infected as pre-pregnancy infection group (Virgin control), which were subsequently mated with ICR males. All mice were inoculated with 1 × 106Plasmodium berghei ANKA-infected RBCs by intraperitoneal injection, and the same amount of saline was given to Malaria- group. We recorded the incidence of adverse pregnancy outcomes and the amounts of offspring in each group. RESULTS: The Virgin group mice were unable to conceive normally, and vaginal bleeding, abortion, or stillbirth appeared in the Malaria+ group. The incidence of adverse pregnancy outcomes was extremely high and statistically significant compared with the control (Malaria-) group (P < 0.05), of which placenta exhibited pathological features associated with human gestational malaria. CONCLUSIONS: The intraperitoneal injection of 1 × 106Plasmodium berghei ANKA-infected RBCs could establish a model of pregnancy-associated malaria in ICR mouse.

Design, synthesis and glycosidase inhibition of DAB derivatives with C-4 peptide and dipeptide branches.

A series of DAB-peptide and DAB-dipeptide derivatives were synthesized from D-tartrate-derived nitrone 18. The DAB peptides 16 are derivatives of trans,trans-3,4-dihydroxy-L-proline. Glycosidase inhibition assay found four of them to be weak and selective bovine liver ß-galactosidase inhibitors, and the C-2' methyl substituted compound 23b showed the most potent ß-galactosidase inhibition (IC50 = 0.66 µM). Molecular docking studies revealed different docking modes of compound 23b compared to those of other DAB-peptides, and partial similarity of compound 23b to DGJ.

Design and synthesis of iso-allo-DNJ and L-isoDALDP derivatives: pursuit of potent and selective inhibitors of α-glucosidase.

A series of iso-allo-DNJ and L-isoDALDP derivatives were synthesized from dithioacetal 16 with sequential and highly diastereoselective Ho and Henry reactions, and aziridinium intermediate-mediated ring rearrangement as key steps. Glycosidase inhibition assay found four of them as selective α-glucosidase inhibitors, and the less substituted compound 30 showed more potent α-glucosidase inhibition (IC50 = 9.3 µM) than the others. Molecular docking study revealed different docking modes of the iso-allo-DNJ and L-isoDALDP derivatives from their parent compounds, and also the similarity of compound 30 to isofagomine.

Erythrocyte membrane with CLIPPKF as biomimetic nanodecoy traps merozoites and attaches to infected red blood cells to prevent Plasmodium infection.

BACKGROUND: Malaria remains a serious threat to global public health. With poor efficacies of vaccines and the emergence of drug resistance, novel strategies to control malaria are urgently needed. RESULTS: We developed erythrocyte membrane-camouflaged nanoparticles loaded with artemether based on the growth characteristics of Plasmodium. The nanoparticles could capture the merozoites to inhibit them from repeatedly infecting normal erythrocytes, owing to the interactions between merozoites and heparin-like molecules on the erythrocyte membrane. Modification with a phosphatidylserine-targeting peptide (CLIPPKF) improved the drug accumulation in infected red blood cells (iRBCs) from the externalized phosphatidylserine induced by Plasmodium infection. In Plasmodium berghei ANKA strain (pbANKA)-infected C57BL/6 mice, the nanoparticles significantly attenuated Plasmodium-induced inflammation, apoptosis, and anemia. We observed reduced weight variation and prolonged survival time in pbANKA-challenged mice, and the nanoparticles showed good biocompatibility and negligible cytotoxicity. CONCLUSION: Erythrocyte membrane-camouflaged nanoparticles loaded with artemether were shown to provide safe and effective protection against Plasmodium infection.

Effect of acupuncture and metformin on insulin sensitivity in women with polycystic ovary syndrome and insulin resistance: a three-armed randomized controlled trial.

STUDY QUESTION: Does acupuncture improve insulin sensitivity more effectively than metformin or sham acupuncture in women with polycystic ovary syndrome (PCOS) and insulin resistance (IR)? SUMMARY ANSWER: Among women with PCOS and IR, acupuncture was not more effective than metformin or sham acupuncture in improving insulin sensitivity. WHAT IS KNOWN ALREADY: Uncontrolled trials have shown that acupuncture improved insulin sensitivity with fewer side effects compared with metformin in women with PCOS and IR. However, data from randomized trials between acupuncture and metformin or sham acupuncture are lacking. STUDY DESIGN, SIZE, DURATION: This was a three-armed randomized controlled trial enrolling a total of 342 women with PCOS and IR from three hospitals between November 2015 and February 2018, with a 3-month follow-up until October 2018. PARTICIPANTS/MATERIALS, SETTING, METHODS: Women aged from 18 to 40 years with PCOS and homeostasis model assessment of insulin resistance (HOMA-IR) ≥2.14 were randomly assigned (n = 114 per group) to receive true acupuncture plus placebo (true acupuncture), metformin plus sham acupuncture (metformin, 0.5 g three times daily) or sham acupuncture plus placebo (sham acupuncture) for 4 months, with an additional 3-month follow-up. True or sham acupuncture was given three times per week, and 0.5 g metformin or placebo was given three times daily. The primary outcome was change in HOMA-IR from baseline to 4 months after baseline visit. Secondary outcomes included changes in the glucose AUC during an oral glucose tolerance test, BMI and side effects at 4 months after baseline visit. MAIN RESULTS AND THE ROLE OF CHANCE: After 4 months of treatment, the changes of HOMA-IR were -0.5 (decreased 14.7%) in the true acupuncture group, -1.0 (decreased 25.0%) in the metformin group and -0.3 (decreased 8.6%) in the sham acupuncture group, when compared with baseline. True acupuncture is not as effective as metformin in improving HOMA-IR at 4 months after baseline visit (difference, 0.6; 95% CI, 0.1-1.1). No significant difference was found in change in HOMA-IR between true and sham acupuncture groups at 4 months after baseline visit (difference, -0.2; 95% CI, -0.7 to 0.3). During the 4 months of treatment, gastrointestinal side effects were more frequent in the metformin group, including diarrhea, nausea, loss of appetite, fatigue, vomiting and stomach discomfort (31.6%, 13.2%, 11.4%, 8.8%, 14.0% and 8.8%, respectively). Bruising was more common in the true acupuncture group (14.9%). LIMITATIONS, REASONS FOR CAUTION: This study might have underestimated the sample size in the true acupuncture group with 4 months of treatment to enable detection of statistically significant changes in HOMA-IR with fixed acupuncture (i.e. a non-personalized protocol). Participants who withdrew because of pregnancy did not have further blood tests and this can introduce bias. WIDER IMPLICATIONS OF THE FINDINGS: True acupuncture did not improve insulin sensitivity as effectively as metformin in women with PCOS and IR, but it is better than metformin in improving glucose metabolism (which might reduce the risk of type 2 diabetes) and has less side effects. Metformin had a higher incidence of gastrointestinal adverse effects than acupuncture groups, and thus acupuncture might be a non-pharmacological treatment with low risk for women with PCOS. Further studies are needed to evaluate the effect of acupuncture combined with metformin on insulin sensitivity in these women. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by grants 2017A020213004 and 2014A020221060 from the Science and Technology Planning Project of Guangdong Province. The authors have no conflicts of interest. TRIAL REGISTRATION NUMBER: Clinicaltrials.gov number: NCT02491333. TRIAL REGISTRATION DATE: 8 July 2015. DATE OF FIRST PATIENT'S ENROLLMENT: 11 November 2015.

Diastereoselective Synthesis, Glycosidase Inhibition, and Docking Study of C-7-Fluorinated Casuarine and Australine Derivatives.

C-7-fluorinated derivatives of two important polyhydroxylated pyrrolizidines, casuarine and australine, were synthesized with organocatalytic stereoselective α-fluorination of aldehydes as the key step. The strategy is extensively applicable to some synthetically challenging fluorinated iminosugars and carbohydrates. The docking studies indicated that the potent inhibitions of trehalase and amyloglucosidase by the fluorinated polyhydroxylated pyrrolizidines are due to the interaction modes dominated by fluorine atoms in these iminosugars with the amino acids' residues of the corresponding enzymes. Steady interactions were established between the C-7 fluoride and a hydrophobic pocket in amyloglucosidase by untypical anion-π interactions. These unexpected docking modes and related structure-activity relationship studies emphasize the value of fluorination in the design of polyhydroxylated pyrrolizidine glycosidase inhibitors.

De Novo Synthesis of Orthogonally-Protected C2-Fluoro Digitoxoses and Cymaroses: Development and Application for the Synthesis of Fluorinated Digoxin.

Inspired by Roush's pioneering work on rare sugars, we have developed a scalable, stereoselective, de novo synthesis of orthogonally protected C2-fluoro digitoxose and cymarose, utilizing Sharpless kinetic resolution and organocatalytic fluorination as key steps. The utility of this strategy is demonstrated by the synthesis of a fluorinated analogue of digoxin, which indicates the fluorine on the sugar ring may have a significant impact on biological activity.

Introduction of C-alkyl branches to L-iminosugars changes their active site binding orientation.

L-ido-Deoxynojirimycin (L-ido-DNJ) itself showed no affinity for human lysosomal acid α-glucosidase (GAA), whereas 5-C-methyl-L-ido-DNJ showed a strong affinity for GAA, comparable to the glucose analog DNJ, with a Ki value of 0.060 µM. This excellent affinity for GAA and enzyme stabilization was observed only when methyl and ethyl groups were introduced. Docking simulation analysis revealed that the alkyl chains of 5-C-alkyl-L-ido-DNJs were stored in three different pockets, depending on their length, thereby the molecular orientation was changed. Comparison of the binding poses of DNJ and 5-C-methyl-L-ido-DNJ showed that they formed a common ionic interaction with Asp404, Asp518, and Asp616, but both the binding orientation and the distance between the ligand and each amino acid residue were different. 5-C-Methyl-L-ido-DNJ dose-dependently increased intracellular GAA activity in Pompe patient fibroblasts with the M519V mutation and also promoted enzyme transport to lysosomes. This study provides the first example of a strategy to design high-affinity ligands by introducing alkyl branches into rare sugars and L-sugar-type iminosugars to change the orientation of binding.

Stereocomplementary synthesis of casuarine and its 6-epi-, 7-epi-, and 6,7-diepi-stereoisomers.

Four diastereomers belonging to the family of casuarines, including casuarine (1), 6-epi-casuarine (2), 7-epi-casuarine (13) and 6,7-diepi-casuarine (14), have been synthesized from D-arabinose-derived cyclic nitrone 7 and nitrone-derived aldehyde 4 by a stereocomplementary strategy. Glycosidase inhibition comparison showed that 6-epi-casuarine (2) exhibits enhanced inhibition of trehalase (IC50 = 9.7 µM) and 6,7-diepi-casuarine (14) leads to specific inhibition of trehalase.

Synthesis and glycosidase inhibition of N-substituted derivatives of 1,4-dideoxy-1,4-imino-d-mannitol (DIM).

N-Substituted derivatives of 1,4-dideoxy-1,4-imino-d-mannitol (DIM), the pyrrolidine core of swainsonine, have been synthesized efficiently and stereoselectively from d-mannose with 2,3:5,6-di-O-isopropylidene DIM (10) as a key intermediate. These N-substituted derivatives include N-alkylated, N-alkenylated, N-hydroxyalkylated and N-aralkylated DIMs with the carbon number of the alkyl chain ranging from one to nine. The obtained 33 N-substituted DIM derivatives were assayed against various glycosidases, which allowed a systematic evaluation of their glycosidase inhibition profiles. Though N-substitution of DIM decreased their α-mannosidase inhibitory activities, some of the derivatives showed significant inhibition of other glycosidases.

MiRNAs expression profiling of rat ovaries displaying PCOS with insulin resistance.

PURPOSE: The present study established microRNA (miRNA) expression profiles for rat ovaries displaying polycystic ovary syndrome (PCOS) with insulin resistance and explored the underlying biological functions of differentially expressed miRNAs. METHODS: A PCOS with insulin resistance rat model was created by administering letrozole and a high-fat diet. Total RNA was extracted from the ovaries of PCOS with insulin resistance rats and normal rats. Three ovaries from each group were used to identify differentially expressed miRNAs by deep sequencing. A hierarchical clustering heatmap and volcano plot were used to display the pattern of differentially expressed miRNAs. Gene ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were conducted to explore the potential target genes of the differentially expressed miRNAs and identify their putative biological function. Nine of the differentially expressed miRNAs were selected for validation by Real-time Quantitative PCR (qRT-PCR). RESULTS: A total of 58 differentially expressed miRNAs were identified in the rat ovaries exhibiting PCOS with insulin resistance compared with control ovaries, including 23 miRNAs that were upregulated and 35 miRNAs that were downregulated. GO and KEGG pathway analyses revealed that the predicted target genes were related to metabolic processes, cellular processes, and metabolic pathways. Furthermore, qRT-PCR confirmed that miR-3585-5p and miR-30-5p were significantly upregulated and miR-146-5p was downregulated in the ovaries of PCOS with insulin resistance rats compared with the controls. CONCLUSION: These results indicate that differentially expressed miRNAs in rat ovaries may be involved in the pathophysiology of insulin resistance in PCOS. Our study may be beneficial in establishing miRNAs as novel diagnostic and therapeutic biomarkers for insulin resistance in PCOS.

Synthesis of Pyrrolidine Monocyclic Analogues of Pochonicine and Its Stereoisomers: Pursuit ofSimplified Structures and Potent ß-N-Acetylhexosaminidase Inhibition.

Ten pairs of pyrrolidine analogues of pochonicine and its stereoisomers have been synthesized from four enantiomeric pairs of polyhydroxylated cyclic nitrones. Among the ten N-acetylamino pyrrolidine analogues, only compounds with 2,5-dideoxy-2,5-imino-d-mannitol (DMDP) and pochonicine (1) configurations showed potent inhibition of ß-N-acetylhexosaminidases (ß-HexNAcases); while 1-amino analogues lost almost all their inhibitions towards the tested enzymes. The assay results reveal the importance of the N-acetylamino group and the possible right configurations of pyrrolidine ring required for this type of inhibitors.

Synthesis and Glycosidase Inhibition of Broussonetine M and Its Analogues.

Cross-metathesis (CM) and Keck asymmetric allylation, which allows access to defined stereochemistry of a remote side chain hydroxyl group, are the key steps in a versatile synthesis of broussonetine M (3) from the d-arabinose-derived cyclic nitrone 14. By a similar strategy, ent-broussonetine M (ent-3) and six other stereoisomers have been synthesized, respectively, starting from l-arabino-nitrone (ent-14), l-lyxo-nitrone (ent-3-epi-14), and l-xylo-nitrone (2-epi-14) in five steps, in 26%-31% overall yield. The natural product broussonetine M (3) and 10'-epi-3 were potent inhibitors of ß-glucosidase (IC50 = 6.3 µM and 0.8 µM, respectively) and ß-galactosidase (IC50 = 2.3 µM and 0.2 µM, respectively); while their enantiomers, ent-3 and ent-10'-epi-3, were selective and potent inhibitors of rice α-glucosidase (IC50 = 1.2 µM and 1.3 µM, respectively) and rat intestinal maltase (IC50 = 0.29 µM and 18 µM, respectively). Both the configuration of the polyhydroxylated pyrrolidine ring and C-10' hydroxyl on the alkyl side chain affect the specificity and potency of glycosidase inhibition.

Concise synthesis of calystegines B2 and B3via intramolecular Nozaki-Hiyama-Kishi reaction.

The key step in the concise syntheses of calystegine B2 and its C-2 epimer calystegine B3 was the construction of cycloheptanone 8via an intramolecular Nozaki-Hiyama-Kishi (NHK) reaction of 9, an aldehyde containing a Z-vinyl iodide. Vinyl iodide 9 was obtained by the Stork olefination of aldehyde 10, derived from carbohydrate starting materials. Calystegines B2 (3) and B3 (4) were synthesized from d-xylose and l-arabinose derivatives respectively in 11 steps in excellent overall yields (27% and 19%).

Epimerization of C5 of an N-hydroxypyrrolidine in the synthesis of swainsonine related iminosugars.

Epimerization of C5 of an N-hydroxypyrrolidine ring by regioselective oxidation to a nitrone followed by diastereoselective reduction provides a new approach to the synthesis of swainsonine and related compounds. The only protection in the synthesis of the potent mannosidase inhibitor DIM (1,4-dideoxy-1,4-imino-d-mannitol) was the acetonation of d-mannose.

First total synthesis of (+)-broussonetine W: glycosidase inhibition of natural product & analogs.

The first total synthesis of (+)-broussonetine W (4), a naturally-occurring pyrrolidine iminosugar isolated from the traditional Chinese medical plant Broussonetia kazinoki SIEB (Moraceae), has been completed through a concise synthetic route starting from the readily available d-arabinose derived cyclic nitrone 10 in 11 steps and 31% overall yield, with regioselective installation of the α,ß-unsaturated ketone functional group by the elimination of HBr from α-bromoketone as the key step. A number of analogs of (+)-broussonetine W (4) with variable side chain length, different polyhydroxylated pyrrolidine core configurations or saturated cyclohexanones have also been prepared to explore the glycosidase inhibition and the preliminary structure-activity relationship of this intriguing class of compounds. Glycosidase inhibition studies identified the natural product (+)-broussonetine W (4) as a selective and potent inhibitor of ß-galactosidase (IC50 = 0.03 µM), while its enantiomer was a selective and potent inhibitor of α-glucosidase (IC50 = 0.047 µM). It was found that the configuration of the polyhydroxylated pyrrolidine ring played a key role on their glycosidase inhibitory activities. The length of side chain and α,ß-unsaturated ketone functional group also exhibited some effect on their glycosidase inhibition.

Gem-difluoromethylated and trifluoromethylated derivatives of DMDP-related iminosugars: synthesis and glycosidase inhibition.

Gem-difluoromethylated and trifluoromethylated derivatives of DMDP-related iminosugars have been synthesized from cyclic nitrones 12, 13, 18, ent-18 or 23 and nitrone-derived aldehydes 20 or ent-20. The fluorinated iminosugars were assayed against various glycosidases, and ent-8 showed moderate but selective α-l-rhamnosidase inhibition. Difluoro or trifluoro units influenced the inhibitory activities of iminosugars in a more complex manner than single fluoro substitution. This may be correlated with their highly hydrophobic character and strong electron-withdrawing effect.

Fluorinated and Conformationally Fixed Derivatives of L-HomoDMDP: Synthesis and Glycosidase Inhibition.

Fluorinated and conformationally fixed derivatives of L-homoDMDP, i.e., 2,5-dideoxy-2,5-imino-DL-glycero-L-manno-heptitol, have been synthesized from d-xylose-derived cyclic nitrone 10 with oxazolidinone 19 or 28 and oxazinanone 22 or 32 as key intermediates. An evaluation of glycosidase inhibition showed replacement of the C-6 hydroxyl groups with fluoride in L-homoDMDP and its C-6 epimer did not have a significant influence on α-glucosidase inhibition by these iminosugars, while replacement of an amino group with a cyclic carbamate group in most conformationally fixed derivatives led to a sharp decrease in the level of glycosidase inhibition, revealing the importance of the free amino group in interaction of enzymes with these molecules.

3-Fluoroazetidinecarboxylic Acids and trans,trans-3,4-Difluoroproline as Peptide Scaffolds: Inhibition of Pancreatic Cancer Cell Growth by a Fluoroazetidine Iminosugar.

Reverse aldol opening renders amides of 3-hydroxyazetidinecarboxylic acids (3-OH-Aze) unstable above pH 8. Aze, found in sugar beet, is mis-incorporated for proline in peptides in humans and is associated with multiple sclerosis and teratogenesis. Aze-containing peptides may be oxygenated by prolyl hydroxylases resulting in potential damage of the protein by a reverse aldol of the hydroxyazetidine; this, rather than changes in conformation, may account for the deleterious effects of Aze. This paper describes the synthesis of 3-fluoro-Aze amino acids as hydroxy-Aze analogues which are not susceptible to aldol cleavage. 4-(Azidomethyl)-3-fluoro-Aze and 3,4-difluoroproline are new peptide building blocks. trans,trans-2,4-Dihydroxy-3-fluoroazetidine, an iminosugar, inhibits the growth of pancreatic cancer cells to a similar degree as gemcitabine.