DIZE treatment reduced diabetes-induced renal damage as shown by reduction of fibrosis and apoptosis. These protective actions of DIZE were blocked by the AT receptor antagonist. Taken together, these results suggest that DIZE protected against DN through the ACE2/angiotensin-(1-7)/ AT receptor axis.
Fibrosis is a central pathway that drives progression of multiple chronic diseases, yet few safe and effective clinical antifibrotic therapies exist. In most fibrotic disorders, transforming growth factor–β (TGF-β)–driven scarring is an important pathologic feature and a key contributor to disease progression. Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) are two closely related transcription cofactors that are important for coordinating fibrogenesis after organ injury, but how they are activated in response to tissue injury has, so far, remained unclear. Here, we describe NUAK family kinase 1 (NUAK1) as a TGF-β–inducible profibrotic kinase that is up-regulated in multiple fibrotic organs in mice and humans. Mechanistically, we show that TGF-β induces a rapid increase in NUAK1 in fibroblasts. NUAK1, in turn, can promote profibrotic YAP and TGF-β/SMAD signaling, ultimately leading to organ scarring. Moreover, activated YAP and TAZ can induce further NUAK1 expression, creating a profibrotic positive feedback loop that enables persistent fibrosis. Using mouse models of kidney, lung, and liver fibrosis, we demonstrate that this fibrogenic signaling loop can be interrupted via fibroblast-specific loss of NUAK1 expression, leading to marked attenuation of fibrosis. Pharmacologic NUAK1 inhibition also reduced scarring, either when initiated immediately after injury or when initiated after fibrosis was already established. Together, our data suggest that NUAK1 plays a critical, previously unrecognized role in fibrogenesis and represents an attractive target for strategies that aim to slow fibrotic disease progression.
Fibrotic diseases account for nearly half of all deaths in the developed world. Despite its importance, the pathogenesis of fibrosis remains poorly understood. Recently, the two mechanosensitive transcription cofactors YAP and TAZ have emerged as important profibrotic regulators in multiple murine tissues. Despite this growing recognition, a number of important questions remain unanswered, including which cell types require YAP/TAZ activation for fibrosis to occur and the time course of this activation. Here, we present a detailed analysis of the role that myofibroblast YAP and TAZ play in organ fibrosis and the kinetics of their activation. Using analyses of cells, as well as multiple murine and human tissues, we demonstrated that myofibroblast YAP and TAZ were activated early after organ injury and that this activation was sustained. We further demonstrated the critical importance of myofibroblast YAP/TAZ in driving progressive scarring in the kidney, lung, and liver, using multiple transgenic models in which YAP and TAZ were either deleted or hyperactivated. Taken together, these data establish the importance of early injury-induced myofibroblast YAP and TAZ activation as a key event driving fibrosis in multiple organs. This information should help guide the development of new antifibrotic YAP/TAZ inhibition strategies.
As per the previous studies, a potential therapy for NAFLD may be the one with multi-faceted actions on insulin resistance, oxidative stress, inflammation and fibrosis. This study demonstrates the efficiency of Esculetin in improving liver fibrosis in HFD induced NAFLD.
Hyperglycaemia-induced expression of extracellular matrix (ECM) components plays a major role in the development of diabetic nephropathy (DN). The epigenetic mechanisms that modulate ECM gene expression in DN remain unclear. Therefore, we examined the role of histone H2A and H2B monoubiquitination on epigenetic chromatin marks, such as histone H3 lysine dimethylation (H3K4Me2, H3K9Me2 and H3K79Me2) in type 1 diabetic rat kidney. Hyperglycaemia increased collagen deposition and Col1a1 gene expression. In whole kidney of diabetic animals, both H2AK119 mono-ubiquitination (H2AK119Ub) and H2BK120 mono-ubiquitination (H2BK120Ub) were found to be increased, whereas, in glomeruli of diabetic animals, expression of both H2AK119Ub and H2BK120Ub was reduced. Changes in ubiquitin proteasome system components like increased Rnf2 (H2A-specific E3 ligase) and decreased H2A- and H2B-specific deubiquitinases (ubiquitin-specific proteases 7, 16, 21 and 22) were also observed. Globally increased levels of chromatin marks associated with active genes (H3K4Me2 and H3K79Me2) and decreased levels of repressive marks (H3K9Me2) were also observed. Hyperglycaemia also increased the protein expression of SET7/9 and decreased the expression of SUV39H1. We also showed the decreased occupancy of H2AK119Ub and H2BK120Ub on the promoters of Set7/9 and Suv39h1 in diabetic kidney. In addition, methylation marks regulated by H2AK119Ub (H3K27Me2 and H3K36Me2) and H2BK120Ub (H3K4Me2 and H3K79Me2) were also found to be altered on the promoters of Set7/9 and Suv39h1 Taken together, these results show the functional role of H2AK119Ub and H2BK120Ub in regulating histone H3K4Me2 and H3K9Me2 through modulating the expression of SET7/9 and SUV39H1 in the development of diabetic renal fibrosis.
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