Genome-wide association studies (GWAS) have successfully identified genetic loci associated with major depressive disorder (MDD), yet the complex gene networks underpinning this polygenic risk remain Show more
Genome-wide association studies (GWAS) have successfully identified genetic loci associated with major depressive disorder (MDD), yet the complex gene networks underpinning this polygenic risk remain largely uncharacterised. Here, we elucidate the neurobiological mechanisms of MDD by analyzing co-expression networks of 94 risk genes in the human prefrontal cortex. By linking these networks to individual symptoms, we identify the FADS1 (fatty acid desaturase 1) network as a central integrator across symptom clusters. We find that the FADS1 network functions primarily in astrocytes to regulate fatty acid metabolism and influence oligodendrocyte-related cell states. Furthermore, we identify FGF2 as a synaptic effector of this pathway and highlight PPARα (peroxisome proliferator-activated receptor alpha) as a putative therapeutic target. These results establish astrocyte fatty acid metabolism as a critical mechanistic contributor to MDD and a promising avenue for treatment. Show less
Caveolins are a family of integral membrane proteins implicated in various cell functions, including the organization and inactivation of signaling molecules of G protein-coupled receptors. We tested Show more
Caveolins are a family of integral membrane proteins implicated in various cell functions, including the organization and inactivation of signaling molecules of G protein-coupled receptors. We tested the ability of human caveolin scaffolding peptide-1 (CSP-1) to regulate norepinephrine- (NE) or histamine (HIS)-induced increases on intracellular calcium concentrations ([Ca(2+)]i). In cultured rat vascular smooth muscle cells (VSMC), CSP-1 inhibited in a concentration-dependent manner NE- and HIS-induced increases in [Ca(2+)]i. This effect can be explained by the fact that CSP-1 inhibited a common signaling pathway. We tested the ability of this peptide to decrease the activation of PLC-beta3 and MAPK. CSP-1 inhibited the expression of the activated form of both enzymes, suggesting a direct effect of the peptide on the signaling cascade. CSP-1 readily enters VSMC in culture, as observed when FITC-conjugated CPS-1 is added to cell culture media. Taken together, these data suggest that CSP-1 blocks the effects of NE and HIS on [Ca(2+)]i of VSMC by inhibiting the activation of PLC-beta3 and MAPK. Show less