14 research outputs found
Cycloastragenol restrains keratinocyte hyperproliferation by promoting autophagy via the miR-145/STC1/Notch1 axis in psoriasis
Psoriasis is characterized by inflammation and hyperproliferation of epidermal keratinocytes. Cycloastragenol (CAG) is an active molecule of Astragalus membranaceus that potentially plays a repressive role in psoriasis. Activated cell autophagy is an effective pathway for alleviating psoriasis progression. Thus, we investigated the role of CAG in the proliferation and autophagy of interleukin (IL)-22-stimulated keratinocytes. A psoriasis model was established by stimulating HaCaT cells with IL-22. Gene or protein expression levels were measured by qRT-PCR or western blot. Autophagy flux was observed with mRFP-GFP-LC3 adenovirus transfection assay under confocal microscopy. Stanniocalcin-1 (STC1) secretion levels were determined using ELISA kits. The apoptosis rate was assessed using flow cytometry. Interactions between miR-145 and STC1 or STC1 and Notch1 were validated by luciferase reporter gene assays, RIP, and Co-IP assays. CAG repressed cell proliferation and promoted apoptosis and autophagy in IL-22-stimulated HaCaT cells. Additionally, CAG promoted autophagy by enhancing miR-145. STC1 silencing ameliorated autophagy repression in IL-22-treated HaCaT cells. Moreover, miR-145 negatively regulated STC1, and STC1 was found to activate Notch1. Lastly, STC1 overexpression reversed CAG-promoted autophagy. CAG alleviated keratinocyte hyperproliferation through autophagy enhancement via regulating the miR-145/STC1/Notch1 axis in psoriasis.</p
The discovery of novel HDAC3 inhibitors via virtual screening and <i>in vitro</i> bioassay
<p>Histone deacetylase 3 (HDAC3) is a potential target for the treatment of human diseases such as cancers, diabetes, chronic inflammation and neurodegenerative diseases. Previously, we proposed a virtual screening (VS) pipeline named “Hypo1_FRED_SAHA-3” for the discovery of HDAC3 inhibitors (HDAC3Is) and had thoroughly validated it by theoretical calculations. In this study, we attempted to explore its practical utility in a large-scale VS campaign. To this end, we used the VS pipeline to hierarchically screen the Specs chemical library. In order to facilitate compound cherry-picking, we then developed a knowledge-based pose filter (PF) by using our in-house quantitative structure activity relationship- (QSAR-) modelling approach and coupled it with FRED and Autodock Vina. Afterward, we purchased and tested 11 diverse compounds for their HDAC3 inhibitory activity <i>in vitro</i>. The bioassay has identified compound <b>2</b> (Specs ID: AN-979/41971160) as a HDAC3I (IC<sub>50</sub> = 6.1 μM), which proved the efficacy of our workflow. As a medicinal chemistry study, we performed a follow-up substructure search and identified two more hit compounds of the same chemical type, i.e. <b>2–1</b> (AQ-390/42122119, IC<sub>50</sub> = 1.3 μM) and <b>2–2</b> (AN-329/43450111, IC<sub>50</sub> = 12.5 μM). Based on the chemical structures and activities, we have demonstrated the essential role of the capping group in maintaining the activity for this class of HDAC3Is. In addition, we tested the hit compounds for their <i>in vitro</i> activities on other HDACs, including HDAC1, HDAC2, HDAC8, HDAC4 and HDAC6. We have identified these compounds are HDAC1/2/3 selective inhibitors, of which compound <b>2</b> show the best selectivity profile. Taken together, the present study is an experimental validation and an update to our earlier VS strategy. The identified hits could be used as starting structures for the development of highly potent and selective HDAC3Is.</p
An Unbiased Method To Build Benchmarking Sets for Ligand-Based Virtual Screening and its Application To GPCRs
Benchmarking data
sets have become common in recent years for the
purpose of virtual screening, though the main focus had been placed
on the structure-based virtual screening (SBVS) approaches. Due to
the lack of crystal structures, there is great need for unbiased benchmarking
sets to evaluate various ligand-based virtual screening (LBVS) methods
for important drug targets such as G protein-coupled receptors (GPCRs).
To date these ready-to-apply data sets for LBVS are fairly limited,
and the direct usage of benchmarking sets designed for SBVS could
bring the biases to the evaluation of LBVS. Herein, we propose an
unbiased method to build benchmarking sets for LBVS and validate it
on a multitude of GPCRs targets. To be more specific, our methods
can (1) ensure chemical diversity of ligands, (2) maintain the physicochemical
similarity between ligands and decoys, (3) make the decoys dissimilar
in chemical topology to all ligands to avoid false negatives, and
(4) maximize spatial random distribution of ligands and decoys. We
evaluated the quality of our Unbiased Ligand Set (ULS) and Unbiased
Decoy Set (UDS) using three common LBVS approaches, with Leave-One-Out
(LOO) Cross-Validation (CV) and a metric of average AUC of the ROC
curves. Our method has greatly reduced the “artificial enrichment”
and “analogue bias” of a published GPCRs benchmarking
set, i.e., GPCR Ligand Library (GLL)/GPCR Decoy Database (GDD). In
addition, we addressed an important issue about the ratio of decoys
per ligand and found that for a range of 30 to 100 it does not affect
the quality of the benchmarking set, so we kept the original ratio
of 39 from the GLL/GDD
The Development of Target-Specific Pose Filter Ensembles To Boost Ligand Enrichment for Structure-Based Virtual Screening
Structure-based virtual
screening (SBVS) has become an indispensable
technique for hit identification at the early stage of drug discovery.
However, the accuracy of current scoring functions is not high enough
to confer success to every target and thus remains to be improved.
Previously, we had developed binary pose filters (PFs) using knowledge
derived from the protein–ligand interface of a single X-ray
structure of a specific target. This novel approach had been validated
as an effective way to improve ligand enrichment. Continuing from
it, in the present work we attempted to incorporate knowledge collected
from diverse protein–ligand interfaces of multiple crystal
structures of the same target to build PF ensembles (PFEs). Toward
this end, we first constructed a comprehensive data set to meet the
requirements of ensemble modeling and validation. This set contains
10 diverse targets, 118 well-prepared X-ray structures of protein–ligand
complexes, and large benchmarking actives/decoys sets. Notably, we
designed a unique workflow of two-layer classifiers based on the concept
of ensemble learning and applied it to the construction of PFEs for
all of the targets. Through extensive benchmarking studies, we demonstrated
that (1) coupling PFE with Chemgauss4 significantly improves the early
enrichment of Chemgauss4 itself and (2) PFEs show greater consistency
in boosting early enrichment and larger overall enrichment than our
prior PFs. In addition, we analyzed the pairwise topological similarities
among cognate ligands used to construct PFEs and found that it is
the higher chemical diversity of the cognate ligands that leads to
the improved performance of PFEs. Taken together, the results so far
prove that the incorporation of knowledge from diverse protein–ligand
interfaces by ensemble modeling is able to enhance the screening competence
of SBVS scoring functions
Maximal Unbiased Benchmarking Data Sets for Human Chemokine Receptors and Comparative Analysis
Chemokine receptors
(CRs) have long been druggable targets for
the treatment of inflammatory diseases and HIV-1 infection. As a powerful
technique, virtual screening (VS) has been widely applied to identifying
small molecule leads for modern drug targets including CRs. For rational
selection of a wide variety of VS approaches, ligand enrichment assessment
based on a benchmarking data set has become an indispensable practice.
However, the lack of versatile benchmarking sets for the whole CRs
family that are able to unbiasedly evaluate every single approach
including both structure- and ligand-based VS somewhat hinders modern
drug discovery efforts. To address this issue, we constructed Maximal
Unbiased Benchmarking Data sets for human Chemokine Receptors (MUBD-hCRs)
using our recently developed tools of MUBD-DecoyMaker. The MUBD-hCRs
encompasses 13 subtypes out of 20 chemokine receptors, composed of
404 ligands and 15756 decoys so far and is readily expandable in the
future. It had been thoroughly validated that MUBD-hCRs ligands are
chemically diverse while its decoys are maximal unbiased in terms
of “artificial enrichment”, “analogue bias”.
In addition, we studied the performance of MUBD-hCRs, in particular
CXCR4 and CCR5 data sets, in ligand enrichment assessments of both
structure- and ligand-based VS approaches in comparison with other
benchmarking data sets available in the public domain and demonstrated
that MUBD-hCRs is very capable of designating the optimal VS approach.
MUBD-hCRs is a unique and maximal unbiased benchmarking set that covers
major CRs subtypes so far
Comparative Modeling and Benchmarking Data Sets for Human Histone Deacetylases and Sirtuin Families
Histone
deacetylases (HDACs) are an important class of drug targets
for the treatment of cancers, neurodegenerative diseases, and other
types of diseases. Virtual screening (VS) has become fairly effective
approaches for drug discovery of novel and highly selective histone
deacetylase inhibitors (HDACIs). To facilitate the process, we constructed
maximal unbiased benchmarking data sets for HDACs (MUBD-HDACs) using
our recently published methods that were originally developed for
building unbiased benchmarking sets for ligand-based virtual screening
(LBVS). The MUBD-HDACs cover all four classes including Class III
(Sirtuins family) and 14 HDAC isoforms, composed of 631 inhibitors
and 24 609 unbiased decoys. Its ligand sets have been validated
extensively as chemically diverse, while the decoy sets were shown
to be property-matching with ligands and maximal unbiased in terms
of “artificial enrichment” and “analogue bias”.
We also conducted comparative studies with DUD-E and DEKOIS 2.0 sets
against HDAC2 and HDAC8 targets and demonstrate that our MUBD-HDACs
are unique in that they can be applied unbiasedly to both LBVS and
SBVS approaches. In addition, we defined a novel metric, i.e. NLBScore,
to detect the “2D bias” and “LBVS favorable”
effect within the benchmarking sets. In summary, MUBD-HDACs are the
only comprehensive and maximal-unbiased benchmark data sets for HDACs
(including Sirtuins) that are available so far. MUBD-HDACs are freely
available at http://www.xswlab.org/
Dioxin-like Potency of HO- and MeO- Analogues of PBDEs’ the Potential Risk through Consumption of Fish from Eastern China
Polybrominated diphenyl ethers (PBDEs) and their analogues,
such
as hydroxylated PBDE (HO-PBDEs) and methoxylated PBDE (MeO-PBDEs)
are of interest due to their wide distribution, bioaccumulation and
potential toxicity to humans and wildlife. While information on the
toxicity/biological potencies of PBDEs was available, information
on analogues of PBDEs was limited. Dioxin-like toxicity of 34 PBDEs
analogues was evaluated by use of the H4IIE-<i>luc</i>,
rat hepatoma transactivation bioassay in 384-well plate format at
concentrations ranging from 0 to 10 000 ng/mL. Among the 34
target analogues of PBDEs studied here, 19 activated the aryl hydrocarbon
receptor (AhR) and induced significant dioxin-like responses in H4IIE-<i>luc</i> cells. Efficacies of the analogues of PBDEs ranged from
5.0% to 101.8% of the maximum response caused by 2,3,7,8-tetrachlorodibenzo-<i>p</i>-dioxin (TCDD-max) and their respective 2,3,7,8-TCDD potency
factors (ReP<sub>H4IIE‑<i>luc</i></sub>) ranged from
7.35 × 10<sup>–12</sup> to 4.00 × 10<sup>–4</sup>, some of which were equal to or more potent than some mono-<i>ortho</i>-substituted PCBs (TEF-<sub>WHO</sub> = 3 × 10<sup>–5</sup>). HO-PBDEs exhibited greater dioxin-like activity
than did the corresponding MeO-PBDEs. Analogues of PBDEs were detected
mostly in marine organisms. Of these 11 detected analogues of PBDEs,
6 were found to have measurable dioxin-like potency. Though some analogues
of PBDEs exhibited significant dioxin-like potency as measured by
responses of the H4IIE-<i>luc</i> transactivation assay,
concentrations of 2,3,7,8-tetrachlorodibenzo-<i>p-</i>dioxin
(TCDD) equivalents (<sup>PBDEs analogues</sup>TEQ<sub>H4IIE‑<i>luc</i></sub>), calculated as the sum of the product of concentrations
of individual PBDE and their ReP<sub>H4IIE‑<i>luc</i></sub>, were less than the tolerance limit proposed by European Union
and the oral reference dose (RfD) derived by U.S. Environmental Protection
Agency, respectively. (Hazard Quotients (HQ) < 0.005) Additional
investigations should be conducted to evaluate the toxic potencies
of these chemicals, especially for 2′-MeO-BDE-28, 4-HO-BDE-90,
6-HO-BDE-47, and 6-MeO-BDE-47, which had been detected in other environmental
media, including human blood
Characterization of Cancer Associated Mucin Type O-Glycans Using the Exchange Sialylation Properties of Mammalian Sialyltransferase ST3Gal-II
Our previous studies suggest that the α2,3sialylated
T-antigen (NeuAcα2,3Galβ1,3GalNac-) and associated glycan
structures are likely to be elevated during cancer. An easy and reliable
strategy to label mucinous glycans that contain such carbohydrates
can enable the identification of novel glycoproteins that are cancer
associated. To this end, the present study demonstrates that the exchange
sialylation property of mammalian ST3Gal-II can facilitate the labeling
of mucin glycoproteins in cancer cells, tumor specimens, and glycoproteins
in cancer sera. Results show that (i) the radiolabeled mucin glycoproteins
of each of the cancer cell lines studied (T47D, MCF7, LS180, LNCaP,
SKOV<sub>3</sub>, HL60, DU4475, and HepG<sub>2</sub>) is distinct
either in terms of the specific glycans presented or their relative
distribution. While some cell lines like T47D had only one single
sialylated O-glycan, others like LS180 and DU4475 contained a complex
mixture of mucinous carbohydrates. (ii) [<sup>14</sup>C]Âsialyl labeling
of primary tumor cells identified a 25–35 kDa mucin glycoprotein
unique to pancreatic tumor. Labeled glycoproteins for other cancers
had higher molecular weight. (iii) Studies of [<sup>14</sup>C] sialylated
human sera showed larger mucin glycopeptides and >2-fold larger
mucin-type chains in human serum compared to [<sup>14</sup>C]Âsialyl
labeled glycans of fetuin. Overall, the exchange sialylation property
of ST3Gal-II provides an efficient avenue to identify mucinous proteins
for applications in glycoproteomics and cancer research
MOESM1 of Resolvin D1 mitigates energy metabolism disorder after ischemia–reperfusion of the rat lung
Additional file 1: Figure S1. Product information
Additional file 1: Table S1. of Parenting style, resilience, and mental health of community-dwelling elderly adults in China
Datasets. (XLSX 121 kb