1,3-Disubstituted-1,2,4-triazin-6-ones with potent activity against androgen receptor-dependent prostate cancer cells.

Synthesis and biological evaluation of a small, focused library of 1,3-disubstituted-1,2,4-triazin-6-ones for in vitro inhibitory activity against androgen-receptor-dependent (22Rv1) and androgen-receptor independent (PC3) castration-resistant prostate cancer (CRPC) cells led to highly active compounds with in vitro IC50 values against 22Rv1 cells of <200 nM, and with apparent selectivity for this cell type over PC3 cells. From metabolic/PK evaluations of these compounds, a 3-benzyl-1-(2,4-dichlorobenzyl) derivative had superior properties and showed considerably stronger activity, by nearly an order of magnitude, against AR-dependent LNCaP and C4-2B cells compared to AR-independent DU145 cells. This lead compound decreased AR expression in a dose and time dependent manner and displayed promising therapeutic effects in a 22Rv1 CRPC xenograft mouse model. Computational target prediction and subsequent docking studies suggested three potential known prostate cancer targets: p38a MAPK, TGF-ß1, and HGFR/c-Met, with the latter case of c-Met appearing stronger, owing to close structural similarity of the lead compound to known pyridazin-3-one derivatives with potent c-Met inhibitory activity. RNA-seq analysis showed dramatic reduction of AR signalling pathway and/or target genes by the lead compound, subsequently confirmed by quantitative PCR analysis. The lead compound was highly inhibitory against HGF, the c-Met ligand, which fitted well with the computational target prediction and docking studies. These results suggest that this compound could be a promising starting point for the development of an effective therapy for the treatment of CRPC.

Mitigating lead-induced osteoporosis: The role of butyrate in gut-bone axis restoration.

Lead (Pb) is an environmentally widespread bone toxic pollutant, contributes to the development of osteoporosis. Butyric acid, mainly produced by the fermentation of indigestible dietary fiber by gut microbiota, plays a pivotal role in the maintenance of bone homeostasis. However, the effects of butyric acids on the Pb induced osteoporosis have not yet been elucidated. In this study, our results showed that Pb exposure was negatively related to the abundance of butyric acid, in the Pb-exposed population and Pb-exposed mice. Pb exposure caused gut microbiota disorders, resulting in the decline of butyric acid-producing bacteria, such as Butyrivibrio_crossotus, Clostridium_sp._JN9, and the butyrate-producing enzymes through the acetyl-CoA pathway. Moreover, results from the NHANES data suggested that dietary intake of butyrate was associated with a reduced risk of osteoporosis in lead-burdened populations, particularly among men or participants aged 18-60 years. In addition, butyrate supplementation in mice with chronic Pb exposure improved the bone microarchitectures, repaired intestinal damage, upregulated the proportion of Treg cells. Taken together, these results demonstrated that chronic Pb exposure disturbs the gut-bone axis, which can be restored by butyric acid supplement. Our results suggest that butyrate supplementation is a possible therapeutic strategy for lead-induced bone toxicity.

KIRA8 attenuates non-alcoholic steatohepatitis through inhibition of the IRE1α/XBP1 signalling pathway.

Endoplasmic reticulum (ER) stress is enhanced in non-alcoholic steatohepatitis (NASH). Among three signalling pathways, the IRE1α/XBP1 signalling pathway is strongly implicated in the pathogenesis of NASH but its significance is still largely uncharacterised. In this report, we constructed a hepatocyte-specific XBP1-Luciferase knock-in mouse model that allows in vivo monitoring of the IRE1α/XBP1 activity in hepatocytes. Using this mouse model, we found that IRE1α/XBP1 was activated within hepatocytes during the pathogenesis of NASH. Significantly, a specific IRE1α kinase-inhibiting RNase attenuator, KIRA8, attenuated NASH in mice. In conclusion, our hepatocyte-specific XBP1 splicing reporter mouse represents a valid model for research and drug development of NASH, which showed that the IRE1α-induced XBP splicing is potentiated in hepatocytes during pathogenesis of NASH. Furthermore, we carried out the proof-of-concept study to demonstrate that the allosteric IRE1α RNase inhibitor serves as a promising therapeutic agent for the treatment of NASH.

The natural compound rutaecarpine promotes white adipocyte browning through activation of the AMPK-PRDM16 axis.

The prevalence of obesity is increasing globally and is associated with many metabolic disorders, such as type 2 diabetes and cardiovascular diseases. In recent years, a number of studies suggest that promotion of white adipose browning represents a promising strategy to combat obesity and its related metabolic disorders. The aim of this study was to identify compounds that induce adipocyte browning and elucidate their mechanism of action. Among the 500 natural compounds screened, a small molecule named Rutaecarpine, was identified as a positive regulator of adipocyte browning both in vitro and in vivo. KEGG pathway analysis from RNA-seq data suggested that the AMPK signaling pathway was regulated by Rutaecarpine, which was validated by Western blot analysis. Furthermore, inhibition of AMPK signaling mitigated the browning effect of Rutaecaripine. The effect of Rutaecaripine on adipocyte browning was also abolished upon deletion of Prdm16, a downstream target of AMPK pathway. In collusion, Rutaecarpine is a potent chemical agent to induce adipocyte browning and may serve as a potential drug candidate to treat obesity.

1-Benzyloxy-5-phenyltetrazole derivatives highly active against androgen receptor-dependent prostate cancer cells.

A series of 1-benzyloxy-5-phenyltetrazole derivatives and similar compounds were synthesized and evaluated for their in vitro inhibitory activity against androgen-receptor-dependent (22Rv1) and androgen-receptor independent (PC3) prostate cancer cells. The most active compounds had in vitro IC50 values against 22Rv1 cells of <50 nM and showed apparent selectivity for this cell type over PC3 cells; however, these active compounds had short half-lives when incubated with mouse liver microsomes and/or when plasma concentration was monitored during in vivo pharmacokinetic studies in mice or rats. Importantly, lead compound 1 exhibited promising inhibitory effects on cell proliferation, expression of AR and its splicing variant AR-v7 as well as AR regulated target genes in 22Rv1 cells, which are so called castration-resistant prostate cancer (CRPC) cells, and a 22Rv1 CRPC xenograft tumour model in mice. Structural changes which omitted the N-O-benzyl moiety led to dramatic or total loss of activity and S-benzylation of a cysteine derivative, as a surrogate for in vivo S-nucleophiles, by representative highly active compounds, suggested a possible chemical reactivity basis for this "activity cliff" and poor pharmacokinetic profile. However, representative highly active compounds did not inhibit a cysteine protease, indicating that the mode of activity is unlikely to be protein modification by S-benzylation. Despite our efforts to elucidate the mode of action, the mechanism remains unclear.

Androgen Receptor is a Negative Regulator of PRDM16 in Beige Adipocyte.

PRDM16 (PR domain containing protein 16) serves as a dominant activator of brown and beige adipocyte. However, mechanisms underlying the regulation of PRDM16 expression are incompletely understood. A Prdm16 luciferase knockin reporter mouse model is generated, enabling high throughput monitoring of Prdm16 transcription. Single clonal analysis reveals high heterogeneity of Prdm16 expression in the inguinal white adipose tissue (iWAT) cells. Amongst all transcription factors, androgen receptor (Ar) shows the strongest negative correlation with Prdm16. A sex dimorphism for PRDM16 mRNA expression is present in human WAT, with female individuals exhibiting increased expression than males. Androgen-AR signaling mobilization suppresses Prdm16 expression, accompanied by attenuated beiging in beige adipocytes, but not in brown adipose tissue. The suppressive effect of androgens on beiging is abolished upon overexpression of Prdm16. Cleavage under targets and tagmentation mapping reveals direct binding of AR within the intronic region of Prdm16 locus, whereas no direct binding is detected on Ucp1 and other browning-related genes. Adipocyte-selective deletion of Ar potentiates beige cell biogenesis whereas adipocyte-specific overexpression of AR attenuates white adipose beiging. This study highlights an essential role of AR in negative regulation of PRDM16 in WAT and provides an explanation for the observed sex difference in adipose beiging.

Comparative transcriptomic analysis of rabbit interscapular brown adipose tissue whitening under physiological conditions.

Interscapular brown adipose tissue (iBAT) of both rabbits and humans exhibits a similar whitening phenomenon under physiological conditions. However, a detailed characterization of iBAT whitening in them is still lacking. Here, we chose rabbits as a model to gain a better understanding of the molecular signature changes during the whitening process of iBAT by transcriptomic analysis of rabbit iBAT at day 1, day 14, 1 month and 4 months after birth. We applied non-invasive MRI imaging to monitor the whitening process and correlated these changes with analysis of morphological, histological and molecular features. Principal component analysis (PCA) of differentially expressed genes delineated three major phases for the whitening process as Brown, Transition and Whitened BAT phases. RNA-sequencing data revealed that whitening of iBAT was an orchestrated process where multiple types of cells and tissues participated in a variety of physiological processes including neovascularization, formation of new nervous networks and immune regulation. Several key metabolic and signalling pathways contributed to whitening of iBAT, and immune cells and immune regulation appeared to play an overarching role.

Discovery of a Highly Selective and H435R-Sensitive Thyroid Hormone Receptor ß Agonist.

The design and development of agonists selectively targeting thyroid hormone receptor ß (TRß) and TRß mutants remain challenging tasks. In this study, we first adopted the strategy of breaking the "His-Phe switch" to solve two problems, simultaneously. A structure-based design approach was successfully utilized to obtain compound 16g, which is a potent TRß agonist (EC50: 21.0 nM, 85.0% of the maximum efficacy of 1) with outstanding selectivity for TRß over TRα and also effectively activates the TRßH435R mutant. Then, we developed a highly efficient synthetic method for 16g. Our serials of cocrystal structures revealed detailed structural mechanisms in overcoming subtype selectivity and rescuing the H435R mutation. 16g also showed excellent lipid metabolism, safety, metabolic stability, and pharmacokinetic properties. Collectively, 16g is a well-characterized selective and mutation-sensitive TRß agonist for further investigating its function in treating dyslipidemia, nonalcoholic steatohepatitis (NASH), and resistance to thyroid hormone (RTH).

Linifanib exerts dual anti-obesity effect by regulating adipocyte browning and formation.

Obesity is caused by energy imbalance and accompanied by adipocyte hypertrophy and hyperplasia. Therefore, both enhancement of adipocyte energy expenditure and inhibition of adipogenesis are viable ways to combat obesity. Using the Ucp1-2A-luciferase reporter animal model previously reported by us as a screening platform, a chemical compound Linifanib was identified as a potent inducer of UCP1 expression in primary inguinal adipocytes in vitro and in vivo. Signal pathway analyses showed that Linifanib promoted adipocyte browning by attenuating STAT3 phosphorylation. The effects of Linifanib on adipocyte browning were blocked by the compound, SD19, which activates the STAT3 signaling cascade. Linifanib also inhibited adipocyte differentiation, by blocking mitotic clonal expansion, which could be rescued by STAT3 activator. Taken together, our results indicate that Linifanib might serve as a potential drug for the treatment of obesity.

The natural compound, formononetin, extracted from Astragalus membranaceus increases adipocyte thermogenesis by modulating PPARγ activity.

BACKGROUND AND PURPOSE: Increasing energy expenditure through adipocyte thermogenesis is generally accepted as a promising strategy to mitigate obesity and its related diseases. However, few clinically effective and safe agents are known to promote adipocyte thermogenesis. In this study, 20 traditional Chinese herbal medicines were screened to examine whether they induced adipocyte thermogenesis. EXPERIMENTAL APPROACH: The effects of Chinese herbal medicines or components isolated from extracts of A. membranaceus, on adipocyte thermogenesis were analysed by assessing expression of uncoupling protein 1 (UCP1) by qPCR. Eight-week-old C57BL6/J male mice were fed a high-fat diet for 8 weeks and then randomized to two groups treated with vehicle or formononetin for another 8 weeks. Glucose tolerance tests and staining of adipose tissue with haematoxylin and eosin were carried out. Whole-body oxygen consumption was measured with an open-circuit indirect calorimetry system. KEY RESULTS: Extracts of A. membranaceus increased expression of Ucp1 in primary cultures of mouse adipocytes. Formononetin was the only known component of A. membranaceus extracts to increase adipocyte Ucp1 expression. Diet-induced obese mice treated with formononetin gained less weight and showed higher energy expenditure than untreated mice. In addition, formononetin binds directly with PPARγ. CONCLUSIONS AND IMPLICATION: Taken together, our study demonstrates that the Chinese herbal medicine from A. membranaceus and its constituent formononetin have the potential to reduce obesity and associated metabolic disorders. Our results suggest that formononetin regulates adipocyte thermogenesis as a non-classical PPARγ agonist.