Implication of overexpression of dishevelled-associated activator of morphogenesis 1 (Daam-1) for the pathogenesis of human Idiopathic Pulmonary Arterial Hypertension (IPAH)

Abstract

BackgroundIdiopathic pulmonary arterial hypertension (IPAH) is a rare, fatal disease of unknown pathogenesis. Evidence from our recent study suggests that IPAH pathogenesis is related to upregulation of the Wnt/planar cell polarity (Wnt/PCP) pathway. We used microscopic observation and immunohistochemical techniques to identify expression patterns of cascading proteins—namely Wnt-11, dishevelled-2 (Dvl-2), and dishevelled-associated activator of morphogenesis 1 (Daam-1)—in pulmonary arteries.MethodsWe analyzed sections of formalin-fixed and paraffin-embedded autopsied lung tissues obtained from 9 IPAH cases, 7 associated pulmonary arterial hypertension cases, and 16 age-matched controls without pulmonary arterial abnormalities. Results of microscopic observation were analyzed in relation to the cellular components and size of pulmonary arteries.ResultsVarying rates of positive reactivity to Dvl-2 and Daam-1 were confirmed in all cellular components of pulmonary arteries, namely, endothelial cells, myofibroblasts, and medial smooth muscle cells. In contrast, none of these components was reactive to Wnt-11. No specific expression patterns were observed for endothelial cells or myofibroblasts under any experimental conditions. However, marked expression of Dvl-2 and Daam-1 was confirmed in smooth muscle cells. In addition, Dvl-2 was depleted while Daam-1 expression was elevated in IPAH, in contrast with specimens from associated pulmonary arterial hypertension cases and controls.ConclusionsHigh Daam-1 expression may upregulate the Wnt/PCP pathway and cause IPAH.

Daam1 negatively regulates USP10 activity

“…Daam1 was detected in lysates from cultured HCFs at a characteristic 123 kDa band, confirming its expression by these cells (Fig 1C). In addition, incubation of HCFs in 2ng/mL of TGFβ1 for 3 days significantly increased Daam1 expression by 1.8-fold (p<0.001), a similar result to what was observed in myofibroblasts in lung samples of idiopathic pulmonary arterial hypertension patients (Yanai et al, 2017), as well as total tissue gene expression analysis of kidney samples following injury (Saito et al, 2015). TGFβ1-induced differentiation of HCFs into myofibroblasts was confirmed by a well-characterized increased in expression of α-SMA (4.7-fold p<0.05).…”

“…Daam1 is a formin protein with a diverse set of functions within cells. Formins, including Daam1, are responsible for actin cytoarchitectural arrangement, facilitating such functions as actin filament polymerization (Yang et al, 2007) and severing (Harris et al, 2004), as well as cross-linking actin into bundles (Esue et al, 2008;Jaiswal et al, 2013). Our data suggest that Daam1 negatively regulates USP10, by sequestering the complex to actin stress fibers.…”

“…Of note was the USP10 interaction signal from the protein Fascin-1 (NCBI Ref # NM_003088), another actin-associated protein that directly interacts with Daam1 on actin bundles in lamellipodia (Jaiswal et al, 2013). These are thought to be structural interactions as using USP10 as bait did not reveal known enzymatic interactions in which USP10 acts as a DUB such as p53 or integrins (Gillespie et al, 2017;Yuan et al, 2010).…”

Identification of Hub Genes and MicroRNAs Associated With Idiopathic Pulmonary Arterial Hypertension by Integrated Bioinformatics Analyses

“…IPAH is a rare but severe cardiopulmonary disease associated with progressive deterioration. There are many molecular mechanisms underlying IPAH, and extant treatments for IPAH are limited ( Yanai et al, 2017 ). To find new targets or therapies, it is essential to explore IPAH hub genes.…”

Noncanonical Wnt planar cell polarity signaling in lung development and disease

“…Expression was confirmed by immunolabeling in the endothelial layer [92]. A separate study did not confirm the presence of WNT11 in pulmonary arteries, but demonstrated that Dvl2 and Daam1 are also present in the surrounding smooth muscle cells [93]. Importantly, the PCP signature was not present in a mouse model of IPAH that a involves repeated intratracheal injection of Stachybotrys chartarum, although the model shows the diminished bone morphogenetic protein (BMP) signaling characteristic of the disease [94].…”