Magnesium lithospermate B improves the gut microbiome and bile acid metabolic profiles in a mouse model of diabetic nephropathy.

Magnesium lithospermate B (MLB) is a new drug marketed in China to treat angina, but its low oral bioavailability limits its clinical application to the intravenous route. Paradoxically, orally administered low-dose MLB was found to alleviate kidney injury in diabetic nephropathy (DN) rats, but its mechanism of action remains unknown. In recent years, the kidney-gut axis has been suspected to be involved in kidney damage pathogenesis, potentially representing a non-classical pathway for pharmacologic intervention. To ascertain whether MLB targets the kidney-gut axis, streptozotocin (STZ)-treated mice were prepared as a mouse model of DN. The STZ mice were treated with MLB (50 mg kg-1 d-1, p.o.) for 8 weeks. Twenty-four-hour urinary albumin was detected to mirror kidney function. At week 4, 6, 8, feces were collected; bile acids (BAs) were quantified to examine the alterations in the BA metabolic profiles, and bacterial 16S rRNA gene fragments were sequenced to identify alterations in gut microbial composition. In STZ mice, 24-h urinary albumin levels and total fecal BAs, especially cholic acids (CAs) and deoxycholic acids (DCAs) were greatly increased, and the gut microbiome was dramatically shifted compared with control mice. Oral administration of MLB significantly decreased 24-h urinary albumin levels and total BAs, CAs and DCAs, and reversed CA:TCA (taurocholic acid) and DCA:CA ratios. It also changed the microbiome composition in STZ mice based on operational units. Thus the therapeutic effect of MLB on kidney injury might be attributed (at least partially) to its ability to modulate the disordered gut microbiome and BA metabolism.

Structure-Guided Discovery of Novel, Potent, and Orally Bioavailable Inhibitors of Lipoprotein-Associated Phospholipase A2.

Lipoprotein-associated phospholipase A2 (Lp-PLA2) is a promising therapeutic target for atherosclerosis, Alzheimer's disease, and diabetic macular edema. Here we report the identification of novel sulfonamide scaffold Lp-PLA2 inhibitors derived from a relatively weak fragment. Similarity searching on this fragment followed by molecular docking leads to the discovery of a micromolar inhibitor with a 300-fold potency improvement. Subsequently, by the application of a structure-guided design strategy, a successful hit-to-lead optimization was achieved and a number of Lp-PLA2 inhibitors with single-digit nanomolar potency were obtained. After preliminary evaluation of the properties of drug-likeness in vitro and in vivo, compound 37 stands out from this congeneric series of inhibitors for good inhibitory activity and favorable oral bioavailability in male Sprague-Dawley rats, providing a quality candidate for further development. The present study thus clearly demonstrates the power and advantage of integrally employing fragment screening, crystal structures determination, virtual screening, and medicinal chemistry in an efficient lead discovery project, providing a good example for structure-based drug design.

Intermediate outcome of a cruciate-retaining tibia.

The use of an all-polyethylene tibia in total knee arthroplasty is being revisited as a means to decrease backside polyethylene wear and lessen cost. The Depuy Sigma all-polyethylene tibia (Depuy Orthopedics, Warsaw, Indiana) has been reported with good outcomes at a greater than 10-year interval, whereas the Biomet AGC I beam design (Biomet, Warsaw, Indiana) has had a high failure rate at an early interval. This is a retrospective review of another design. One hundred seventy patients (190 cruciate-retaining total knee replacements) with a Scorpio (Stryker, Mahwah, New Jersey) all-polyethylene implant and tibia were identified in the authors' registry. This implant was chosen for all octogenarians deemed fit for a cruciate-retaining knee and a few septuagenarians who were deemed likely to remain inactive postoperatively for reasons other than knee arthritis. Mean follow-up was 38 months (range, 24-83 months). Mean patient age was 83.1 years (range, 72.7-93.8 years). Twenty-seven patients (29 knees) were lost to follow-up. Nineteen patients (24 knees) died before 24-month follow-up; all implants were in place, and no deaths were associated with the index procedure. Fifty-one patients (55 knees) were followed by telephone interview only and 75 patients (81 knees) by an office visit with radiograph analysis. One tibia revision was performed 2 months postoperatively for an implant placed in extension and varus. No infections, component wear, radiolucent lines, or impending revisions of the remaining cohort occurred. Lower Extremity Activity Scale scores ranged from 2 to 10 (mean score, 6.8), which demonstrated success even in patients with an active lifestyle. This previously unreported design is a promising all-polyethylene tibia alternative for total knee arthroplasty in older patients.

Design, synthesis, and structure-activity relationships of 3,4,5-trisubstituted 4,5-dihydro-1,2,4-oxadiazoles as TGR5 agonists.

Given its role in the mediation of energy and glucose homeostasis, the G-protein-coupled bile acid receptor 1 (TGR5) is considered a potential target for the treatment of type 2 diabetes mellitus and other metabolic disorders. By thorough analysis of diverse structures of published TGR5 agonists, a hypothetical ligand-based pharmacophore model was built, and a new class of potent TGR5 agonists, based on the novel 3,4,5-trisubstituted 4,5-dihydro-1,2,4-oxadiazole core, was discovered by rational design. Three distinct synthetic methods for constructing 4,5-dihydro-1,2,4-oxadiazoles and extensive structure-activity relationship studies are reported herein. Compound (R)-54 n, the structure of which was determined by single-crystal X-ray diffraction and quantum chemical solid-state TDDFT-ECD calculations, showed the best potency, with an EC50 value of 1.4 nM toward hTGR5. Its favorable properties in vitro warrant further investigation.

Pyrazolidine-3,5-dione derivatives as potent non-steroidal agonists of farnesoid X receptor: virtual screening, synthesis, and biological evaluation.

The identification of a novel pyrazolidine-3,5-dione based scaffold hit compound as Farnesoid X receptor (FXR) partial or full agonist has been accomplished by means of virtual screening techniques. A series of pyrazolidine-3,5-dione derivatives (1a-u and 7) was designed, synthesized, and evaluated by a cell-based luciferase transactivation assay for their agonistic activities against FXR. Most of them showed agonistic potencies and 10 of them (1a, 1b, 1d-f, 1j, 1n, 1t, 5b, and 7) exhibited lower EC(50) values than the reference drug CDCA. Molecular modeling studies for the representative compounds 1a, 1d, 1f, 1j, 1n, 1u, 5b, and 7 were also presented. The novel structural scaffold has provided a new direction for finding potent and selective FXR partial and full agonists (referred to as 'selective bile acid receptor modulators', SBARMs).

Dopamine D1 receptor agonist and D2 receptor antagonist effects of the natural product (-)-stepholidine: molecular modeling and dynamics simulations.

(-)-Stepholidine (SPD), an active ingredient of the Chinese herb Stephania, is the first compound found to have dual function as a dopamine receptor D1 agonist and D2 antagonist. Insights into dynamical behaviors of D1 and D2 receptors and their interaction modes with SPD are crucial in understanding the structural and functional characteristics of dopamine receptors. In this study a computational approach, integrating protein structure prediction, automated molecular docking, and molecular dynamics simulations were employed to investigate the dual action mechanism of SPD on the D1 and D2 receptors, with the eventual aim to develop new drugs for treating diseases affecting the central nervous system such as schizophrenia. The dynamics simulations revealed the surface features of the electrostatic potentials and the conformational "open-closed" process of the binding entrances of two dopamine receptors. Potential binding conformations of D1 and D2 receptors were obtained, and the D1-SPD and D2-SPD complexes were generated, which are in good agreement with most of experimental data. The D1-SPD structure shows that the K-167_EL-2-E-302_EL-3 (EL-2: extracellular loop 2; EL-3: extracellular loop 3) salt bridge plays an important role for both the conformational change of the extracellular domain and the binding of SPD. Based on our modeling and simulations, we proposed a mechanism of the dual action of SPD and a subsequent signal transduction model. Further mutagenesis and biophysical experiments are needed to test and improve our proposed dual action mechanism of SPD and signal transduction model.

Use of an alumina-on-alumina bearing system in total hip arthroplasty for osteonecrosis of the hip.

BACKGROUND: The results of total hip arthroplasty in patients with osteonecrosis of the femoral head are not always optimal. The use of alumina-on-alumina interfaces in young and active patients may decrease wear and lower the rate of aseptic loosening of the implant and appears to be an attractive alternative to the use of conventional cobalt-chromium-on-polyethylene bearings. The purpose of this study was to evaluate the safety and efficacy of the alumina-on-alumina bearing in patients with osteonecrosis and to compare this group of patients to a group of similarly treated patients with osteoarthritis and a group of patients who received conventional cobalt-chromium-on-polyethylene bearings. METHODS: Patients were selected from a United States Investigational Device Exemption multicenter prospective randomized clinical study that was initiated in 1996. Seventy patients with osteonecrosis of the femoral head (seventy-nine hips) received a cementless alumina-on-alumina bearing system and were directly matched to seventy-six patients with osteoarthritis of the hip (seventy-nine hips) who were managed with the same implant. Both groups were compared with twenty-five patients (twenty-six hips) with osteonecrosis and twenty-five patients (twenty-six hips) with osteoarthritis who were managed with a cementless cobalt-chromium-on-polyethylene bearing system. All patients received a cementless hydroxyapatite-coated femoral stem and were followed both clinically and radiographically. RESULTS: The clinical outcomes for alumina-on-alumina bearings were similar for both osteonecrotic and osteoarthritic hips. The seven-year survival probability was 95.5% for the osteonecrotic hips and 89.4% for the osteoarthritic hips in the alumina-on-alumina bearing group and 92.3% for the osteonecrotic hips and 92.9% for the osteoarthritic hips in the cobalt-chromium-on-polyethylene bearing group. At the time of the most recent follow-up, the mean Harris hip score was 96 points for both the osteonecrotic and the osteoarthritic hips in the alumina-on-alumina group and 96 points for the osteonecrotic hips and 97 points for the osteoarthritic hips in the cobalt-chromium-on-polyethylene bearing group. CONCLUSIONS: The results of the use of alumina-on-alumina and cobalt-chromium-on-polyethylene bearings in cementless standard total hip implants in patients with osteonecrosis and osteoarthritis were comparable. The low revision rate for the alumina-on-alumina bearing is encouraging and offers a promising option for younger, more active patients who have this challenging disease. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions to Authors on jbjs.org for a complete description of levels of evidence.

Discovering severe acute respiratory syndrome coronavirus 3CL protease inhibitors: virtual screening, surface plasmon resonance, and fluorescence resonance energy transfer assays.

An integrated system has been developed for discovering potent inhibitors of severe acute respiratory syndrome coronavirus 3C-like protease (SARS-CoV 3CL(pro)) by virtual screening correlating with surface plasmon resonance (SPR) and fluorescence resonance energy transfer (FRET) technologies-based assays. The authors screened 81,287 small molecular compounds against SPECS database by virtual screening; 256 compounds were subsequently selected for biological evaluation. Through SPR technology-based assay, 52 from these 256 compounds were discovered to show binding to SARS-CoV 3CL(pro). The enzymatic inhibition activities of these 52 SARS-CoV 3CL(pro) binders were further applied to FRET-based assay, and IC(50) values were determined. Based on this integrated assay platform, 8 new SARS-CoV 3CL(pro) inhibitors were discovered. The fact that the obtained IC(50) values for the inhibitors are in good accordance with the discovered dissociation equilibrium constants (K(D)s) assayed by SPR implied the reliability of this platform. Our current work is hoped to supply a powerful approach in the discovery of potent SARS-CoV 3CL(pro) inhibitors, and the determined inhibitors could be used as possible lead compounds for further research.

Comparison of microbial community between two shallow freshwater lakes in middle Yangtze basin, East China.

In order to investigate the role of the microbial community in aquatic ecology and nutrient transformations in the development of eutrophication in large shallow freshwater lakes along Yangtze River, the microbial community in the depth-related sediment in Lake Chaohu and Lake Longganhu were compared. Lake Chaohu is one of the three most polluted lakes in China. However, the neighboring Lake Longganhu, a mesotrophic lake, is relatively pristine. The total phosphorous (TP) and total nitrogen (TN) concentration in water was detected at 0.193 mgl(-1) and 3.035 mgl(-1) for Lake Chaohu, 0.051 mgl(-1) and 0.774 mgl(-1) for Lake Longganhu, respectively. The population of the microorganisms with various ecological nutrient transforming functions (e.g. phosphate solubilizing, denitrifying and cellulose decomposing) and a batch of environmental parameters concerning the nutrient accumulating and transforming (e.g. total organic carbon, total nitrogen, and total phosphorous concentrations) were assayed in the depth-related sediment samples from several defined points in both lakes. The sediment samples from Lake Chaohu showed higher density of actinomycetes (P<0.05) and phosphate-solubilizing bacteria (P<0.001) and less profusion of denitrifying bacteria (P<0.05) and cellulolytic microbes (P<0.001), compared with those of Lake Longganhu. The data suggested that the current microbial community in the sediment of Lake Chaohu is in favor of sustaining or further accelerating the process of the lake eutrophication. A possible positive feedback loop which consists of sustained growth of microorganisms and gradual decline of lake eutrophic status is worth further discussing.

Cinanserin is an inhibitor of the 3C-like proteinase of severe acute respiratory syndrome coronavirus and strongly reduces virus replication in vitro.

The 3C-like proteinase (3CLpro) of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) is one of the most promising targets for anti-SARS-CoV drugs due to its crucial role in the viral life cycle. In this study, a database containing structural information of more than 8,000 existing drugs was virtually screened by a docking approach to identify potential binding molecules of SARS-CoV 3CLpro. As a target for screening, both a homology model and the crystallographic structure of the binding pocket of the enzyme were used. Cinanserin (SQ 10,643), a well-characterized serotonin antagonist that has undergone preliminary clinical testing in humans in the 1960s, showed a high score in the screening and was chosen for further experimental evaluation. Binding of both cinanserin and its hydrochloride to bacterially expressed 3CLpro of SARS-CoV and the related human coronavirus 229E (HCoV-229E) was demonstrated by surface plasmon resonance technology. The catalytic activity of both enzymes was inhibited with 50% inhibitory concentration (IC50) values of 5 microM, as tested with a fluorogenic substrate. The antiviral activity of cinanserin was further evaluated in tissue culture assays, namely, a replicon system based on HCoV-229E and quantitative test assays with infectious SARS-CoV and HCoV-229E. All assays revealed a strong inhibition of coronavirus replication at nontoxic drug concentrations. The level of virus RNA and infectious particles was reduced by up to 4 log units, with IC50 values ranging from 19 to 34 microM. These findings demonstrate that the old drug cinanserin is an inhibitor of SARS-CoV replication, acting most likely via inhibition of the 3CL proteinase.

Swietenia mahagony extract shows agonistic activity to PPAR(gamma) and gives ameliorative effects on diabetic db/db mice.

AIM: To search the peroxisome proliferator-activated receptor g (PPAR(gamma)) agonists from Swietenia mahagony extract (SmE) and observe the possible ameliorative effects of SmE on diabetic db/db mice. METHODS: The PPAR(gamma) agonistic activity of SmE was screened by yeast-two hybrid system. The blood glucose levels of diabetic db/db mice were measured using a blood glucose level monitor and the data were statistically analyzed by NDST8.8W software. RESULTS: By using the clinical drug rosiglitazone as a positive control, it was found that the PPARg agonistic activity of SmE at a concentration of 50 microg/L was approximately half that of 35.7 microg/L (0.1 micromol/L) of rosiglitazone. At the dose of 1000 mg/kg, SmE remarkably decreased the blood glucose concentration of db/db mice from (15.26+/-2.98) to (7.58+/-2.20) mmol/L, and reduced the blood glucose levels by 55.49% compared with the control group (P<0.01). CONCLUSION: SmE shows agonistic activity to PPARg and can ameliorate the blood glucose levels of diabetic db/db mice. SmE may be thus used as a potential agent for diabetes therapy.

A yeast two-hybrid technology-based system for the discovery of PPARgamma agonist and antagonist.

Peroxisome proliferator-activated receptor gamma (PPARgamma) is an important therapeutic drug target against several diseases such as diabetes, inflammation, dyslipidemia, hypertension, and cancer. Ligand binding to PPARgamma is responsible for controlling the biological functions, and developing new technology to measure ligand-PPARgamma binding is significant for both the function study of the receptor and ligand discovery. In this study, we exploited an efficient approach for the discovery of PPARgamma agonist and antagonist via a yeast two-hybrid system based on the fact that PPARgamma interacts with the coactivator CBP (CREP-binding protein) ligand-dependently. We employed the MEL1 reporter gene instead of the traditionally used LacZ gene to evaluate the protein-protein interactions by conducting a convenient alpha-galactosidase assay in the yeast strain AH109 with genes of PPARgamma-LBD (ligand-binding domain) and CBP N terminus introduced. With this built screening platform, the EC(50) values of the PPARgamma agonists rosiglitazone, troglitazone, pioglitazone, indomethacin, 15-deoxy-Delta12,14-prostaglandin J(2) (15d-PGJ(2)), and GI262570 were investigated, and the quantitatively antagonistic effect by IC(50) of the PPARgamma typical antagonist GW9662 on the rosiglitazone agonistic activity was fully examined. The reliability of this presented system evaluated by the comparable agreement of EC(50) and IC(50) values for the test compounds with the reported ones indicated that this yeast two-hybrid-based approach is powerful for PPARgamma agonist and antagonist screening. In addition, because this screening system is designed for use in a microtiter plate format where numerous chemicals could be readily screened, it is hoped that this yeast two-hybrid screening approach may be adaptable for high-throughput settings.

Acupuncture increases nocturnal melatonin secretion and reduces insomnia and anxiety: a preliminary report.

The response to acupuncture of 18 anxious adult subjects who complained of insomnia was assessed in an open prepost clinical trial study. Five weeks of acupuncture treatment was associated with a significant (p = 0.002) nocturnal increase in endogenous melatonin secretion (as measured in urine) and significant improvements in polysomnographic measures of sleep onset latency (p = 0.003), arousal index (p = 0.001), total sleep time (p = 0.001), and sleep efficiency (p = 0.002). Significant reductions in state (p = 0.049) and trait (p = 0.004) anxiety scores were also found. These objective findings are consistent with clinical reports of acupuncture's relaxant effects. Acupuncture treatment may be of value for some categories of anxious patients with insomnia.

Virtual screening on natural products for discovering active compounds and target information.

Natural products, containing inherently large-scale structural diversity than synthetic compounds, have been the major resources of bioactive agents and will continually play as protagonists for discovering new drugs. However, how to access this diverse chemical space efficiently and effectively is an exciting challenge for medicinal chemists and pharmacologists. While virtual screening, which has shown a great promise in drug discovery, will play an important role in digging out lead (active) compounds from natural products. This review focuses on the strategy of virtual screening based on molecular docking and, with successful examples from our laboratory, illustrates the efficiency of virtual screening in discovering active compounds from natural products. On the other hand, the sequencing of the human genome and numerous pathogen genomes has resulted in an unprecedented opportunity for discovering potential new drug targets. Chemogenomics has appeared as a new technology to initiate target discovery by using active compounds as probes to characterize proteome functions. Natural products are the ideal probes for such research. Binding affinity fingerprint is a powerful chemogenomic descriptor to characterize both small molecules and pharmacologically relevant proteins. Therefore, this review also discusses binding affinity fingerprint strategy for identifying target information from the genomic data by using natural products as the probes.