A novel plasminogen activator inhibitor‐1 inhibitor, TM5441, protects against high‐fat diet‐induced obesity and adipocyte injury in mice

Abstract

Obesity is one of the most prevalent chronic diseases worldwide, and dysregulated adipocyte function plays an important role in obesity-associated metabolic disorder. The level of plasma plasminogen activator inhibitor-1 (PAI-1) is increased in obese subjects, and PAI-1 null mice show improved insulin sensitivity when subjected to high-fat and high-sucrose diet-induced metabolic stress, suggesting that a best-in-class PAI-1 inhibitor may become a novel therapeutic agent for obesity-associated metabolic syndrome. TM5441 is a novel orally active PAI-1 inhibitor that does not cause bleeding episodes. Hence, in the present study we examined the preventive effect of TM5441 on high-fat diet (HFD)-induced adipocyte dysfunction. EXPERIMENTAL APPROACHTen-week-old C57BL/6J mice were fed a normal diet (18% of total calories from fat) or HFD (60% of total calories from fat) for 10 weeks, and TM5441 (20 mg·kg À1 oral gavage) was administered daily with the initiation of HFD. KEY RESULTSTM5441 prevented HFD-induced body weight gain and systemic insulin resistance. TM5441 normalized HFD-induced dysregulated JNK and Akt phosphorylation, suggesting that it prevents the insulin resistance of adipocytes. TM5441 also attenuated the macrophage infiltration and increased expression of pro-inflammatory cytokines, such as inducible nitric oxide synthase, induced by the HFD. In addition, TM5441 prevented the HFD-induced down-regulation of genes involved in mitochondrial biogenesis and function, suggesting that it may prevent adipocyte inflammation and dysregulation by maintaining mitochondrial fitness. CONCLUSION AND IMPLICATIONSOur data suggest that TM5441 may become a novel therapeutic agent for obesity and obesity-related metabolic disorders.Abbreviations ATGL, adipose triglyceride lipase; Cox, cytochrome c oxidase; FAS, fatty acid synthase; FFA, free fatty acid; GTT, glucose tolerance test; H&E, haematoxylin and eosin; HFD, high-fat diet; HSL, hormone-sensitive lipase; iNOS, inducible nitric oxide synthase; ITT, insulin tolerance test; KO, knockout; MCP-1, monocyte chemotactic protein-1; mtDNA, mitochondrial DNA; ND, normal diet; PAI-1, plasminogen activator inhibitor-1; PGC1α, PPARγ coactivator-1α; Tfam, mitochondrial transcription factor A; TG, triglyceride; TM5275, 5-chloro-2- [({2-[4-(diphenylmethyl)piperazin-1-yl]-2-oxoethoxy}acetyl) amino]benzoate; TM5441, 5-chloro-2 {[(2-{[3-(furan-3-yl)phenyl]amino}-2-oxoethoxy) acethyl]amino} benzoic acid; UCP, uncoupling protein; WAT, white adipose tissue

Stress granules counteract senescence by sequestration of PAI‐1

“…A recent study showed that while overexpression/secretion of PAI‐1 led to premature aging in mice, the disruption of PAI‐1 production reversed this phenotype . Moreover, various disease states, such as cancer, cardiovascular disease, and diabetes, are also correlated with increased PAI‐1 expression and secretion . Therefore, developing ways to interfere with PAI‐1 function has been the focus of several groups since the establishment of its role in aging‐related diseases.…”

“…D (left) Western blot analysis was performed using whole-cell extracts from PRO cells, and antibodies specific for pRb (S795) and Rb proteins. cardiovascular disease, and diabetes, are also correlated with increased PAI-1 expression and secretion [68,76]. Therefore, developing ways to interfere with PAI-1 function has been the focus of several groups since the establishment of its role in aging-related diseases.…”

“…Since PAI-1 is a well-known promoter of senescence downstream of p53 [8,11,66], its depletion or chemical inhibition should impact the induction of senescence similarly to when primary fibroblasts are repeatedly exposed to AS. To determine the importance of PAI-1 in this process, we used specific siRNA duplexes to knockdown PAI-1 expression and employed the well-established small-molecule inhibitor of PAI-1 TM5441 ( Fig 7A) [12,13,[67][68][69]. Our data indicate that both PAI-1 knockdown ( Fig 7B) and TM5441-mediated inhibition ( Fig 7C) were sufficient to promote a significant decrease in the number of b-galactosidase-positive cells in the presence or absence of AS treatment.…”

“…Cells induced into senescence were treated with 10 lM TM5441 (Tocris Bioscience) for 24 h daily after treatment with AS [12,13,[67][68][69].…”

Caffeine-Stimulated Intestinal Epithelial Cells Suppress Lipid Accumulation in Adipocytes

“…PAI-1 belongs to a family of serine protease inhibitors, and an increased plasma PAI-1 level has been associated with insulin resistance (27). Knockout of PAI-1 suppresses weight gain in mice (28), and some pharmacological inhibitors of PAI-1 improve high fat diet-induced obesity in mice (29,30), indicating that inhibition of PAI-1 reduces adipogenesis. Although IL-8 increases the leptin secretion in human adipocytes (31), the effect of IL-8 derived from Caco-2 on fat accumulation in adipocytes is unclear.…”