Cannabinoids and PPAR Ligands: The Future in Treatment of Polycystic Ovary Syndrome Women with Obesity and Reduced Fertility

Cannabinoids (CBs) are used to treat chronic pain, chemotherapy-induced nausea and vomiting, and multiple sclerosis spasticity. Recently, the medicinal use of CBs has attracted increasing interest as a new therapeutic in many diseases. Data indicate a correlation between CBs and PPARs via diverse mechanisms. Both the endocannabinoid system (ECS) and peroxisome proliferator-activated receptors (PPARs) may play a significant role in PCOS and PCOS related disorders, especially in disturbances of glucose-lipid metabolism as well as in obesity and fertility. Taking into consideration the ubiquity of PCOS in the human population, it seems indispensable to search for new potential therapeutic targets for this condition. The aim of this review is to examine the relationship between metabolic disturbances and obesity in PCOS pathology. We discuss current and future therapeutic interventions for PCOS and related disorders, with emphasis on the metabolic pathways related to PCOS pathophysiology. The link between the ECS and PPARs is a promising new target for PCOS, and we examine this relationship in depth

Ligands of peroxisome proliferator-activated receptor-γ increase the generation of vascular endothelial growth factor in vascular smooth muscle cells and in macrophages.

Peroxisome proliferator-activated receptors-γ (PPARγ) are ligand-inducible transcription factors of the nuclear hormone receptor superfamily. We examined the effect of PPARγ activation on the generation of vascular endothelial growth factor (VEGF), one of the major angiogenic agents. Rat vascular smooth muscle cells (VSMC) and murine macrophages RAW264.7 were incubated for 24 h with PPARγ activators: prostaglandin J2 and ciglitazone. PPARγ were expressed in VSMC and RAW cells and their activity was upregulated in the presence of PGJ2 and ciglitazone. Incubation of the cells with PPARγ activators significantly augmented the release of VEGF protein into the media, both in resting and in IL-1β- or LPS-stimulated cultures. The higher protein generation was connected with the increased expression of mRNA and transcriptional activation of VEGF promoter. We conclude that the activation of PPARγ upregulates the generation of VEGF and may be involved in the regulation of angiogenesis

PPAR γ\gamma regulates MITF and β−catenin\beta-catenin expression and promotes a differentiated phenotype in mouse melanoma S91

Melanoma represents one of the most rapidly metastasizing, hence deadly tumors due to its high proliferation rate and invasiveness, characteristics of undifferentiated embryonic tissues. Given the absence of effective therapy for metastatic melanoma, understanding more fully the molecular mechanisms underlying melanocyte differentiation may provide opportunities for novel therapeutic intervention. Here we show that in mouse melanoma S91 cells activation of the peroxisome proliferators activated receptor (PPAR) γ induces events resembling differentiation, such as growth arrest accompanied by apoptosis, spindle morphology and enhanced tyrosinase expression. These events are preceded by an initial transient increase in expression from the Microphthalmia-associated transcription factor gene, (MITF) promoter, whereas exposure to a PPAR γ ligand- ciglitazone that exceeds 8 h, causes a gradual decrease of MITF, until by 48 h MITF expression is substantially reduced. Beta-catenin, an MITF transcriptional activator, shows a similar pattern of decline during ciglitazone treatment, consistent with previous reports that activated PPAR γ inhibits the Wnt/β-catenin pathway through induction of β-catenin proteasomal degradation. We suggest that the PPAR γ-mediated β-catenin down-regulation is likely to be responsible for changes in MITF levels. The data suggest that PPAR γ, besides its well-established role in mesenchymal cell differentiation towards adipocytes, might regulate differentiation in the melanocytic lineage