Non-Heme Iron Enzymes Catalyze Heterobicyclic and Spirocyclic Isoquinolone Core Formation in Piperazine Alkaloid Biosynthesis.

We report the discovery and biosynthesis of new piperazine alkaloids-arizonamides, and their derived compounds-arizolidines, featuring heterobicyclic and spirocyclic isoquinolone skeletons, respectively. Their biosynthetic pathway involves two crucial non-heme iron enzymes, ParF and ParG, for core skeleton construction. ParF has a dual function facilitating 2,3-alkene formation of helvamide, as a substrate for ParG, and oxidative cleavage of piperazine. Notably, ParG exhibits catalytic versatility in multiple oxidative reactions, including cyclization and ring reconstruction. A key amino acid residue Phe67 was characterized to control the formation of the constrained arizonamide B backbone by ParG.

The Design, Structure-Activity, and kinetic studies of 3-Benzyl-5-oxa-1,2,3,4-Tetrahydro-2H-chromeno-(3,4-c)pyridin-8-yl sulfamates as Steroid sulfatase inhibitors.

Steroid sulfatase inhibitors block the local production of estrogenic steroids and are attractive agents for the treatment of estrogen-dependent cancers. Inspiration of coumarin-based inhibitors, we synthesized thirty-two 5-oxa-1,2,3,4-tetrahydro-2H-chromeno-(3,4-c)pyridin-8-yl sulfamates, focusing on the substitution derivatives on the adjacent phenyl ring and evaluated their abilities to block STS from human placenta and MCF-7 cells. SAR analysis revealed that the incorporation of chlorine at either meta and/or para position of the adjacent phenyl ring of the tricyclic skeleton enhanced STS inhibition. Di-substitutions at the adjacent phenyl ring were superior to mono and tri-substitutions. Further kinetic analysis of these compounds revealed that chloride-bearing compounds, such as 19m, 19v, and 19w, had KI of 0.02 to 0.11 nM and kinact/KI ratios of 8.8-17.5 nM-1min-1, a parameter indicated for the efficiency of irreversible inhibition. We also used the docking model to illustrate the difference in STS inhibitory potency of compounds. Finally, the safety and anti-cancer activity of selected compounds 19m, 19v, and 19w were also studied, showing the results of low cytotoxicity on NHDF cell line and being more potent than irosustat on ZR-75-1 cell, which was a hormone-dependent cancer cell line with high STS expression.

Rosmarinic acid ameliorated psoriatic skin inflammation in mice through the novel inhibition of the interleukin-17A/interleukin-17A receptor interaction.

The interaction between interleukin-17A (IL-17A) and IL-17A receptor (IL-17RA) is a crucial target of psoriasis. Several natural compounds from foods or herbs have displayed efficacies on the amelioration of psoriasis. However, the anti-psoriatic mechanisms are mostly through the common anti-inflammatory effects and rarely via the blockage of the IL-17A/IL-17RA interaction. In this study, the IL-17A/IL-17RA-targeting effects of phenylpropanoids, a large class of secondary metabolites in plants, were analyzed. By screening 17 phenylpropanoids, we found that top four compounds with IL-17A/IL-17RA-blocking abilities were rosmarinic acid, eugenol, syringic acid, and gallic acid, with inhibitory concentrations at 50% of 2.14 ± 0.35 mM, 6.35 ± 0.1 mM, 4.79 ± 0.2 mM, and >10 mM, respectively. The oral administration of rosmarinic acid ameliorated redness and scaling on the dorsal skin of imiquimod-induced psoriatic mice in a dose-dependent manner. Rosmarinic acid suppressed the production of IL-23 and IL-17A and the infiltration of granulocyte subsets in skin tissues. Docking analysis showed that rosmarinic acid docked into IL-17A/IL-17RA interaction regions and exhibited hydrogen bonding with Arg-61, Glu-68, Arg-100, and Ser-118 of IL-17A, which are located in the epitope regions recognized by IL-17A neutralizing antibodies Fab6785 and Fab6468. In conclusion, this is the first study reporting that rosmarinic acid is an IL-17A-targeting agent that ameliorates psoriatic skin inflammation in mice via blocking the IL-17A/IL-17RA interaction.

The novel anti-inflammatory activity of mcIRBP from Momordica charantia is associated with the improvement of diabetic nephropathy.

Diabetic nephropathy is an inflammatory immune disorder accompanying diabetes. A trypsin inhibitor of Momordica charantia, mcIRBP, is an abundant 68 amino acid residue protein that interacts with the insulin receptor. Here the long-term effects of mcIRBP on the improvement of diabetic nephropathy were determined. Type 2 diabetic mice (db/db) were given mcIRBP administered orally for 12 consecutive weeks. Histological changes relating to the kidney were evaluated using Periodic Acid Schiff and Sirius Red staining. The mcIRBP-affected gene expression profile in the kidney was determined using RNA-Seq. The renoprotective mechanism of mcIRBP was elucidated based on ex vivo imaging and immunohistochemistry staining. Data showed that the administration of mcIRBP significantly decreased fasting blood glucose and glycated hemoglobin A1c (HbA1c) levels by 61% and 27.92%, respectively, suggesting that mcIRBP exhibited HbA1c-lowering abilities in diabetic mice. RNA sequencing (RNA-Seq) analysis showed that the majority of the mcIRBP-affected biological pathways were associated with inflammation and immunity, and the nuclear factor-κB (NF-κB) signaling pathway was significantly affected by mcIRBP. Ex vivo imaging showed that mcIRBP significantly decreased NF-κB-driven bioluminescence in the kidney by 46 ± 23%. The levels of the renal function indices, Evans blue dye content, fibrosis lesions, and cytokine expression were significantly decreased by mcIRBP, suggesting that mcIRBP improved vascular leakage and the pathological and inflammatory characteristics of diabetic nephropathy. This is the first study reporting that, in addition to blood glucose regulation, mcIRBP can act as a novel renoprotective and anti-inflammatory polypeptide, thereby improving diabetic nephropathy in db/db mice. In addition, this study suggested that there was a potential medicinal use of mcIRBP for the management of diabetes and its complications.

A gastro-resistant peptide from Momordica charantia improves diabetic nephropathy in db/db mice via its novel reno-protective and anti-inflammatory activities.

Diabetic nephropathy (DN), a principal diabetic microvascular complication, is a chronic inflammatory immune disorder. A gastro-resistant peptide mcIRBP-9 from Momordica charantia has shown modulation of blood glucose homeostasis in diabetic mice. Here we conducted a long-term experiment to evaluate the therapeutic effects and mechanisms of mcIRBP-9 on DN. Type 2 diabetic mice (db/db mice) were orally given mcIRBP-9 once daily for 12 consecutive weeks. The amelioration of DN was evaluated by renal function indexes, vascular leakage, and pathological lesions. Possible effective mechanisms of mcIRBP-9 on DN were analyzed by gene expression profiles. A pharmacokinetic study in rats was carried out to evaluate the oral bioavailability of mcIRBP-9. Our data showed that mcIRBP-9 was able to enter systemic circulation in rats after oral administration. In comparison with mock, long-term administration of mcIRBP-9 significantly decreased blood glucose (572.25 ± 1.55 mg dL-1vs. 213.50 ± 163.39 mg dL-1) and HbA1c levels (13.58 ± 0.30% vs. 8.23 ± 2.98%) and improved the survival rate (85.7% vs. 100%) in diabetic mice. mcIRBP-9 ameliorated DN by reducing renal vascular leakage and histopathological changes. mcIRBP-9 altered the pathways involved in inflammatory and immune responses, and the nuclear factor-κB played a central role in the regulation of mcIRBP-9-affected pathways. Moreover, mcIRBP-9 improved the inflammatory characteristic of DN in diabetic and non-diabetic mice. In conclusion, mcIRBP-9 displayed a novel anti-inflammatory activity and exhibited a reno-protective ability in addition to controlling the blood glucose and HbA1c levels. These findings suggested the role of mcIRBP-9 from M. charantia as a nutraceutical agent for diabetes and subsequent DN.

Correction: The novel anti-inflammatory activity of mcIRBP from Momordica charantia is associated with the improvement of diabetic nephropathy.

Correction for 'The novel anti-inflammatory activity of mcIRBP from Momordica charantia is associated with the improvement of diabetic nephropathy' by Pei-Yung Liao et al., Food Funct., 2022, DOI: 10.1039/d1fo03620c.

The protective effect of quercetin on retinal inflammation in mice: the involvement of tumor necrosis factor/nuclear factor-κB signaling pathways.

Quercetin is a natural flavonoid that occurs in fruits and vegetables. Retinal inflammation is an important cause of vision loss. This study was aimed to analyze the effects of oral administration of quercetin on retinal inflammation. Transgenic mice, carrying nuclear factor-κB (NF-κB)-driven luciferase genes, were injected with 1 mg per kg body weight of lipopolysaccharide (LPS). Various amounts (1, 10, and 100 mg per kg body weight) of quercetin were orally given to mice. LPS-induced retinal inflammation was evaluated by bioluminescence imaging and histological examination 4 hours later. RNA-Seq analysis of gene expression profiles was performed to explain the mechanisms of quercetin on eye inflammation. Our data showed that LPS enhanced luminescent signals on ocular tissues, while LPS-induced luminescence intensities were significantly suppressed by quercetin by 73.61 ± 21.74%. LPS significantly increased the thickness of retinal tissues by 1.52 ± 0.37 fold, in comparison with the mock, while quercetin reduced the LPS-induced retinal thickness and decreased the accumulation of infiltrating granulocytes. Biological pathway analysis showed that tumor necrosis factor (TNF), cytokine, and NF-κB signaling pathways were involved in the anti-inflammatory mechanisms of quercetin. Immunohistochemical staining further showed that quercetin reduced the activation of NF-κB, the expression of interleukin-1ß and TNF-α, and the infiltration of granulocytes in retinal tissues. In conclusion, this is the first study reporting the effects and mechanisms of orally administered quercetin against LPS-induced retinal inflammation in mice. Due to its safety, our study suggested that supplementation of quercetin has beneficial effects on the eyes.

Design and synthesis of 3-benzylaminocoumarin-7-O-sulfamate derivatives as steroid sulfatase inhibitors.

Steroid sulfatase (STS) is a sulfatase enzyme that catalyzes the conversion of sulfated steroid precursors to free steroid. The inhibition of STS could abate estrogenic steroids that stimulate the proliferation and development of breast cancer, and therefore STS is a potential target for adjuvant endocrine therapy. In this study, a series of 3-benzylaminocoumarin-7-O-sulfamate derivatives targeting STS were designed and synthesized. Structure-relationship activities (SAR) analysis revealed that attachment of a benzylamino group at the 3-position of coumarin improved inhibitory activity. Compound 3j was found to have the highest inhibition activity against human placenta isolated STS (IC50  0.13 µM) and MCF-7 cell lines (IC50 1.35 µM). Kinetic studies found compound 3j to be an irreversible inhibitor of STS, with KI and kinact value of 86.9 nM and 158.7 min-1, respectively.

Ferulic acid altered IL-17A/IL-17RA interaction and protected against imiquimod-induced psoriasis-like skin injury in mice.

Ferulic acid (FA), a phenolic phytochemical, is commonly found in grains, vegetables, and fruits. Interleukin-17A (IL-17A) and IL-17 receptor A (IL-17RA) interaction is one of important therapeutic targets for psoriasis. Here we analyzed the FA effects on IL-17A/IL-17RA interaction and psoriasis-like skin injury induced by imiquimod (IMQ). IL-17A-blocking assay and docking analysis showed that FA interacted with Trp-67, Gln-94, and Glu-95 residues of IL-17A via hydrogen bonds and consequently abolished the binding of IL-17RA to IL-17A. Mice were topically given with IMQ and orally given with various amounts of FA for 14 consecutive days. FA attenuated IMQ-induced psoriasis-like skin lesions in a dose-dependent manner, and the epidermal thickness of mice treated with 100 mg/kg FA was reduced by 53.48 ±â€¯4.44% in comparison with sham. Global analysis of differentially expressed genes showed that IMQ and FA significantly affected immune response, metabolism, and mitogen-activated protein kinase signaling pathways. Immunohistochemical staining showed that FA inhibited the infiltration and the cytokine secretion of Th17 cell, dendritic cell, and granulocyte subsets in psoriatic skin tissues. In conclusion, we newly identified that oral administration of FA protected against IMQ-induced psoriatic skin injury in mice. Moreover, its protection was associated with the interference of IL-17A/IL-17RA interaction.

Optofluidic refractive-index sensors employing bent waveguide structures for low-cost, rapid chemical and biomedical sensing.

We propose and develop an intensity-detection-based refractive-index (RI) sensor for low-cost, rapid RI sensing. The sensor is composed of a polymer bent ridge waveguide (BRWG) structure on a low-cost glass substrate and is integrated with a microfluidic channel. Different-RI solutions flowing through the BRWG sensing region induce output optical power variations caused by optical bend losses, enabling simple and real-time RI detection. Additionally, the sensors are fabricated using rapid and cost-effective vacuum-less processes, attaining the low cost and high throughput required for mass production. A good RI solution of 5.31 10-4 × RIU-1 is achieved from the RI experiments. This study demonstrates mass-producible and compact RI sensors for rapid and sensitive chemical analysis and biomedical sensing.