Transforming growth factor β (TGF-β), a key mediator of fibrotic responses, is increased in asthma and drives airway remodeling by inducing expression of extracellular matrix (ECM) proteins. We investigated the molecular mechanisms underlying TGF-β-induced ECM expression by airway smooth muscle cells and demonstrate a novel link between TGF-β and Wingless/integrase 1 (WNT) signaling in ECM deposition. Airway smooth muscle expresses abundant WNT ligands, with the noncanonical WNT-5A being the most profoundly expressed. Interestingly, WNT-5A shows ∼2-fold higher abundance in airway smooth muscle cells isolated from individuals with asthma than individuals without asthma. WNT-5A is markedly induced in response to TGF-β (4-16-fold; EC₅₀ 0.3 ng/ml) and is required for collagen and fibronectin expression by airway smooth muscle. WNT-5A engages noncanonical WNT signaling pathways, as inhibition of Ca(2+) and c-Jun N-terminal kinase (JNK) signaling attenuated this TGF-β response, whereas the canonical WNT antagonist Dickkopf 1 (DKK-1) did not. Accordingly, WNT-5A induced JNK phosphorylation and nuclear translocation of nuclear factor of activated T cells c1 (NFATc1). Furthermore, silencing of the WNT-5A receptors Frizzled 8 (FZD8) and RYK attenuated TGF-β-induced ECM expression. Collectively, these findings demonstrate that noncanonical WNT-5A signaling is activated by and necessary for TGF-β-induced ECM production by airway smooth muscle cells, which could have significance in asthma pathogenesis.

BackgroundCurrent therapy for relieving bronchoconstriction may be ineffective in severe asthma, particularly in the small airways. The aim of this study was to further characterise responses to the recently identified novel bronchodilators rosiglitazone (RGZ) and chloroquine (CQ) under conditions where β-adrenoceptor agonist efficacy was limited or impaired in mouse small airways within lung slices.MethodsRelaxation to RGZ and CQ was assessed following submaximal methacholine (MCh) pre-contraction, in slices treated overnight with either RGZ, CQ or albuterol (ALB) (to induce β-adrenoceptor desensitization), and in slices treated with caffeine/ryanodine in which contraction is associated with increases in Ca2+ sensitivity in the absence of contractile agonist-induced Ca2+ oscillations. Furthermore, the effects of RGZ, CQ, ALB and isoproterenol (ISO) on the initiation and development of methacholine-induced contraction were also compared.ResultsRGZ and CQ, but not ALB or ISO, elicited complete relaxation with increasing MCh pre-contraction and maintained their potency and efficacy following β-adrenoceptor desensitization. RGZ, CQ and ALB maintained efficacy following overnight incubation with RGZ or CQ. Relaxation responses to all dilators were generally maintained but delayed after caffeine/ryanodine. Pre-treatment with RGZ, but not CQ, ALB or ISO, reduced MCh potency.ConclusionsThis study demonstrates the superior effectiveness of RGZ in comparison to CQ and β-adrenoceptor agonists as a dilator of mouse small airways. Further investigation of the mechanisms underlying the relatively greater efficacy of RGZ under these conditions are warranted and should be extended to include studies in human asthmatic airways.

Background Selective serotonin reuptake inhibitors (SSRIs) exert substantial variability in effectiveness in patients with major depressive disorder (MDD), with up to 50-60% not achieving adequate response. Elucidating pharmacokinetic factors that explain this variability is important to increase treatment effectiveness. Objectives To examine potential modification of the relationship between paroxetine serum concentration (PSC) and serotonin transporter (SERT)-occupancy by single nucleotide polymorphisms (SNPs) of the ABCB1 gene, coding for the P-glycoprotein (P-gp) pump, in MDD patients. To investigate the relationship between ABCB1 SNPs and clinical response. Methods Patients had MDD and received paroxetine 20 mg/day. We measured PSC after 6 weeks. We quantified SERT-occupancy with SPECT imaging (n = 38) and measured 17-item Hamilton Depression Rating Scale (HDRS 17)-scores at baseline and after 6 weeks (n = 81). We genotyped ABCB1 at rs1045642 [3435C>T], rs1128503 [1236C>T], rs2032582 [2677G>T/A] and rs2235040 [2505G>A]. For our primary aim, we modeled mean SERT-occupancy in an E max nonlinear regression model with PSC and assessed whether the model improved by genetic subgrouping. For our secondary aim, we used multivariate linear regression analysis. Results The rs1128503 and rs2032582 SNPs modified the relationship between PSC and SERT-occupancy in both our intention-to-treat and sensitivity analyses at the carriership level. However, we could not detect significant differences in clinical response between any of the genetic subgroups. Conclusion Pharmacokinetic influences of the ABCB1 rs1128503 and rs2032582 represent a potentially relevant pharmacogenetic mechanism to consider when evaluating paroxetine efficacy. Future studies are needed to support the role of ABCB1 genotyping for individualizing SSRI pharmacotherapy.

Patients from outpatient departments for mood and anxiety disorders may be at substantial risk for medication discrepancies that are often clinically relevant. Medication reconciliation at mental health care outpatient departments is in need of improvement.