A transgenic mouse model for the in vivo bioluminescence imaging of the expression of the lysophosphatidic acid receptor 3: relevance for inflammation and uterine physiology research

Abstract

Lysophosphatidic acid (LPA) is a lipid-derived signaling molecule that plays key roles in diverse biological processes including inflammation and uterine remodeling. Although the function of LPA and its receptors has been extensively studied using knock-out mice, the temporal-spatial expression of LPA receptors is less well-characterized. To gain further insight into the dynamic regulation of LPA receptor 3 (Lpar3) expression in vivo by bioluminescence imaging, we generated and characterized mice transgenic for a putative Lpar3 promoter fragment. A non-coding region of the Lpar3 gene immediately upstream of the start site was subcloned adjacent to the luciferase gene. Promoter activity was determined by in vitro luciferase assays, in vivo bioluminescent imaging or by semi-quantitative real-time PCR. The air-pouch model was used to investigate Lpar3 promoter activity in the context of inflammation. The putative Lpar3 promoter fragment behaved similarly to the endogenous promoter in vitro and in vivo. In male mice, elevated levels of Lpar3-induced luciferase activity were observed in the testis. In female mice, the basal level of luciferase activity in the uterus significantly increased during pseudopregnancy. Moreover, luciferase activity was upregulated by TNF-α in the air-pouch model. We report the identification of a functional Lpar3 promoter fragment and the generation of a transgenic mouse model to investigate the regulation of Lpar3 promoter activity non-invasively in vivo by bioluminescence imaging. This mouse model is a valuable tool for reproductive biology and inflammation research as well as other biological processes in which this receptor is involved.

Retracted: Microrna‐139‐5p inhibits epithelial‐mesenchymal transition and fibrosis in post‐menopausal women with interstitial cystitis by targeting LPAR4 via the PI3K/Akt signaling pathway

“…12 LPA also played a crucial role in various biological processes such as inflammation and uterine remodeling. 30 A previous study showed that exogenous LPA contributed to inflammatory responses by modulating the expression of cytokine and its receptors of lung epithelial cells, which was in consistency with ours. 31 LPA4 can couple to Gα12/13, which activates Rho/ROCK, inducing neurite retraction and stress fiber formation with activation of other LPARs.…”

“…For example, LPAR4 was a potential regulator of malignant behavior in head and neck squamous cell carcinoma cells and a potential therapeutic target . LPA also played a crucial role in various biological processes such as inflammation and uterine remodeling . A previous study showed that exogenous LPA contributed to inflammatory responses by modulating the expression of cytokine and its receptors of lung epithelial cells, which was in consistency with ours .…”

Production of extracellular lysophosphatidic acid in the regulation of adipocyte functions and liver fibrosis

“…LPA 3 prefers 2-acyl-LPAs containing unsaturated fatty acids[ 83 ]. It mediates the activation of a series of physiological processes such as male and female reproductive physiology, inflammation, cell Ca 2+ homeostasis and cAMP regulation[ 107 , 117 - 119 ]. LPA 3 appears to determine vertebrate left-right patterning during embryogenesis as downregulation of Lpar3 or inhibition of LPA 3 activity disrupted patterning process in zebrafish[ 120 ].…”

“…Lpar3 -/- mice are viable with no reported neural deficits, even though LPA 3 is found in the frontal cortex, hippocampus, and amygdala[ 83 , 116 ]. On the other hand, female Lpar3 -/- mice have a delayed embryo implantation, and reduced litter size[ 117 ].…”