Endometrial mesenchymal stromal cells (E-MSCs) extensively contribute to the establishment and progression of endometrial ectopic lesions through formation of the stromal vascular tissue, and support ...to its growth and vascularization. As E-MSCs lack oestrogen receptors, endometriosis eradication cannot be achieved by hormone-based pharmacological approaches. Quinagolide is a non-ergot-derived dopamine receptor 2 agonist reported to display therapeutic effects in in vivo models of endometriosis. In the present study, we isolated E-MSCs from eutopic endometrial tissue and from ovarian and peritoneal endometriotic lesions, and we tested the effect of quinagolide on their proliferation and matrix invasion ability. Moreover, the effect of quinagolide on E-MSC endothelial differentiation was assessed in an endothelial co-culture model of angiogenesis. E-MSC lines expressed dopamine receptor 2, with higher expression in ectopic than eutopic ones. Quinagolide inhibited the invasive properties of E-MSCs, but not their proliferation, and limited their endothelial differentiation. The abrogation of the observed effects by spiperone, a dopamine receptor antagonist, confirmed specific dopamine receptor activation. At variance, no involvement of VEGFR2 inhibition was observed. Moreover, dopamine receptor 2 activation led to downregulation of AKT and its phosphorylation. Of interest, several effects were more prominent on ectopic E-MSCs with respect to eutopic lines. Together with the reported effects on endometrial and endothelial cells, the observed inhibition of E-MSCs may increase the rationale for quinagolide in endometriosis treatment.
Sepsis and septic shock are among the most common causes of death in the intensive care unit; advanced therapeutic approaches are thus urgently needed. Vascular hyperpermeability represents a major ...manifestation of severe sepsis and is responsible for the ensuing organ dysfunction and failure. Vasopressin V
receptor (V
R) agonists have shown promise in the treatment of sepsis, increasing blood pressure, and reducing vascular hyperpermeability. The effects of the selective V
R-selective agonist selepressin have been investigated in an in vitro model of thrombin-, vascular endothelial growth factor-, angiopoietin 2-, and lipopolysaccharide (LPS)-induced pulmonary microvascular endothelial hyperpermeability. Results suggest that selepressin counteracts the effects of all four endothelial barrier disruptors in a concentration-dependent manner, as reflected in real-time measurements of vascular permeability by means of transendothelial electrical resistance. Further, selepressin protected the barrier integrity against the LPS-mediated corruption of the endothelial monolayer integrity, as captured by VE-cadherin and actin staining. The protective effects of selepressin were abolished by silencing of the vasopressin V
R, as well as by atosiban, an antagonist of the human V
R. p53 appears to be involved in mediating these palliative effects, since selepressin strongly induced its expression levels, suppressed the inflammatory RhoA/myosin light chain2 pathway, and triggered the barrier-protective effects of the GTPase Rac1. We conclude that V
R-selective agonists, such as selepressin, may prove useful in the improvement of endothelial barrier function in the management of severe sepsis. SIGNIFICANCE STATEMENT: A cardinal sign of sepsis, a serious disease with significant mortality and no specific treatment, is pulmonary endothelial barrier dysfunction that leads to pulmonary edema. Here, we present evidence that in cultured human lung microvascular endothelial cells, the synthetic, selective vasopressin V
receptor agonist selepressin protects against endothelial barrier dysfunction caused by four different edemogenic agents, suggesting a potential role of selepressin in the clinical management of sepsis.
Recombinant FSH proteins are important therapeutic agents for the treatment of infertility, including follitropin alfa expressed in Chinese Hamster Ovary (CHO) cells and, more recently, follitropin ...delta expressed in the human cell line PER.C6. These recombinant FSH proteins have distinct glycosylation, and have distinct pharmacokinetic and pharmacodynamic profiles in women. Comparative experiments demonstrated that follitropin delta and follitropin alfa displayed the same in vitro potency at the human FSH receptor, but varied in their pharmacokinetics in mouse and rat. While follitropin delta clearance from serum depended in part on the hepatic asialoglycoprotein receptor (ASGPR), follitropin alfa clearance was unaffected by ASGPR inhibition in rat or genetic ablation in mice. The distinct properties of follitropin delta and follitropin alfa are likely to contribute to the differing pharmacokinetic and pharmacodynamic profiles observed in women and to influence their efficacy in therapeutic protocols for the treatment of infertility.
The availability of genomic information significantly increases the number of potential targets available for drug discovery, although the function of many targets and their relationship to disease ...is unknown. In a chemical genomic research approach, ultra-high throughput screening (uHTS) of genomic targets takes place early in the drug discovery process, before target validation. Target-selective modulators then provide drug leads and pharmacological research tools to validate target function. Effective implementation of a chemical genomic strategy requires assays that can perform uHTS for large numbers of genomic targets. Cell-based functional assays are capable of the uHTS throughput required for chemical genomic research, and their functional nature provides distinct advantages over ligand-binding assays in the identification of target-selective modulators.
A chemical genomic strategy can drive productive drug discovery in the genomic era. Functional cell-based uHTS assays offer many advantages in the chemical genomic discovery of small molecule drugs.
Retinoid X receptor (RXR) plays a central role in the regulation of many intracellular receptor signalling pathways and can mediate ligand-dependent transcription, acting as a homodimer or as a ...heterodimer. Here we identify an antagonist towards RXR homodimers which also functions as an agonist when RXR is paired as a heterodimer to specific partners, including peroxisome proliferator-activated receptor and retinoic acid receptor. This dimer-selective ligand confers differential interactions on the transcription machinery: the antagonist promotes association with TAF110 (TATA-binding protein (TBP)-associated factor 110) and the co-repressor SMRT, but not with TBP, and these properties are distinct from pure RXR agonists. This unique class of RXR ligands will provide a means to control distinct target genes at the level of transcription and allow the development of retinoids with a new pharmacological action.
Drugs targeting retinoid receptors have been developed to treat a variety of therapeutic indications, but their success has been limited in part due to lack of selectivity. A novel functional ...cell-based assay R-SAT™ was employed to screen a small molecule chemical library and identify a variety of novel RAR agonists with various subtype selectivities, including RARβ/γ and RARγ selective agonists. A novel class of synthetic compounds that distinguishes between the different RARβ isoforms is described. This pharmacophore displays anti-proliferative activity and induces differentiation in a neuronal cell line, consistent with a classical retinoid mechanism of action while providing unique subtype selectivity. These novel subtype selective RAR agonists could serve as powerful tools to probe into subtype and isoform-specific retinoid function.
Peroxisome proliferator-activated
receptor-γ (PPARγ) agonists such as the thiazolidinediones are
insulin sensitizers used in the treatment of type 2 diabetes. These
compounds induce adipogenesis in ...cell culture models and increase
weight gain in rodents and humans. We have identified a novel PPARγ
ligand, LG100641, that does not activate PPARγ but selectively and
competitively blocks thiazolidinedione-induced PPARγ activation and
adipocyte conversion. It also antagonizes target gene activation as
well as repression in agonist-treated 3T3-L1 adipocytes. This
novel PPARγ antagonist does not block adipocyte differentiation
induced by a ligand for the retinoid X receptor (RXR), the
heterodimeric partner for PPARγ, or by a differentiation
cocktail containing insulin, dexamethasone, and
1-methyl-3-isobutylxanthine. Surprisingly, LG100641, like the
PPARγ agonist rosiglitazone, increases glucose uptake in
3T3-L1 adipocytes. Such selective PPARγ antagonists may help
determine whether insulin sensitization by thiazolidinediones is
mediated solely through PPARγ activation, and whether there are
PPARγ-ligand-independent pathways for adipocyte differentiation. If
selective PPARγ modulators block adipogenesis in vivo,
they may prevent obesity, lower insulin resistance, and delay the onset
of type 2 diabetes.
A functional cell-based screen identified 3-(4-chlorophenyl)-3-(2-(dimethylamino)ethyl)isochroman-1-one hydrochloride (AC-7954, 1) as a nonpeptidic agonist of the urotensin-II receptor. Racemic 1 had ...an EC50 of 300 nM at the human UII receptor and was highly selective. Testing of the enantiopure (+)- and (−)- 1 revealed that the UII receptor activity of racemic 1 resides primarily in (+)-1. Being a selective nonpeptidic druglike UII receptor agonist, (+)-1 will be useful as a pharmacological research tool and a potential drug lead.
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