Ameliorative Effects of Osthole on Experimental Renal Fibrosis in vivo and in vitro by Inhibiting IL-11/ERK1/2 Signaling

Chronic Kidney Disease Diets for Kidney Failure Prevention: Insights from the IL-11 Paradigm

Nearly every fifth adult in the United States and many older adults worldwide are affected by chronic kidney disease (CKD), which can progress to kidney failure requiring invasive kidney replacement therapy. In this review, we briefly examine the pathophysiology of CKD and discuss emerging mechanisms involving the physiological resolution of kidney injury by transforming growth factor beta 1 (TGFβ1) and interleukin-11 (IL-11), as well as the pathological consequences of IL-11 overproduction, which misguides repair processes, ultimately culminating in CKD. Taking these mechanisms into account, we offer an overview of the efficacy of plant-dominant dietary patterns in preventing and managing CKD, while also addressing their limitations in terms of restoring kidney function or preventing kidney failure. In conclusion, this paper outlines novel regeneration strategies aimed at developing a reno-regenerative diet to inhibit IL-11 and promote repair mechanisms in kidneys affected by CKD.

Nrf2 knockout attenuates the astragaloside IV therapeutic effect on kidney fibrosis from liver cancer by regulating pSmad3C/3L pathways

Fibrotic kidney injury from hepatocarcinogenesis seriously impacts treatment effect. Astragaloside IV (AS-IV), an extract of Astragalus membranaceus, has several pharmacological activities, which are useful in the treatment of edema and fibrosis. Nrf2/HO-1 is a key antioxidant stress pathway and help treatment of kidney injury. Smad3 phosphorylation is implicated in hepatocarcinogenesis. Our previous study clarified that Smad3 is differentially regulated by different phosphorylated forms of Smad3 on hepatocarcinogenesis. Therefore, we investigated the contribution of AS-IV on the therapy of kidney fibrosis from hepatocarcinogenesis. And the focus was on whether the phosphorylation of Smad3 and the regulation of Nrf2/HO-1 pathway were involved during AS-IV therapy and whether there is an effect of Nrf2 knockout on the phosphorylation of Smad3. We performed TGF-β1 stimulation on HK-2 cells and intervened with AS-IV. Furtherly, we investigated renal injury of AS-IV on Nrf2 knockout mice during hepatocarcinogenesis and its mechanism of action. On the one hand, in vitro results showed that AS-IV reduced the ROS and α-SMA expression of HK-2 by promoting the expression pSmad3C/p21 of and Nrf2/HO-1 and suppressed the expression of pSmad3L/PAI-1. On the other hand, the in vivo results of histopathological features, serological biomarkers, and oxidative damage indicators showed that Nrf2 knockout aggravated renal injury. Besides, Nrf2 deletion decreased the nephroprotective effect of AS-IV by suppressing the pSmad3C/p21 pathway and promoting the pSmad3L/PAI-1 pathway. The experimental results were as we suspected. And we identify for the first time that Nrf2 deficiency increases renal fibrosis from hepatocarcinogenesis and attenuates the therapeutic effects of AS-IV via regulating pSmad3C/3L signal pathway.

Molecular pathogenesis of subretinal fibrosis in neovascular AMD focusing on epithelial-mesenchymal transformation of retinal pigment epithelium

Age-related macular degeneration (AMD) is a leading cause of vision loss among elderly people in developed countries. Neovascular AMD (nAMD) accounts for more than 90% of AMD-related vision loss. At present, intravitreal injection of anti-vascular endothelial growth factor (anti-VEGF) is widely used as the first-line therapy to decrease the choroidal and retinal neovascularizations, and thus to improve or maintain the visual acuity of the patients with nAMD. However, about 1/3 patients still progress to irreversible visual impairment due to subretinal fibrosis even with adequate anti-VEGF treatment. Extensive literatures support the critical role of epithelial-mesenchymal transformation (EMT) of retinal pigment epithelium (RPE) in the pathogenesis of subretinal fibrosis in nAMD, but the underlying mechanisms still remain largely unknown. This review summarized the molecular pathogenesis of subretinal fibrosis in nAMD, especially focusing on the transforming growth factor-β (TGF-β)-induced EMT pathways. It was also discussed how these pathways crosstalk and respond to signals from the microenvironment to mediate EMT and contribute to the progression of nAMD-related subretinal fibrosis. Targeting EMT signaling pathways might provide a promising and effective therapeutic strategy to treat subretinal fibrosis secondary to nAMD.

Research Progress of Chinese Herbal Medicine Intervention in Renal Interstitial Fibrosis

Chronic kidney diseases usually cause renal interstitial fibrosis, the prevention, delay, and treatment of which is a global research hotspot. However, no definite treatment options are available in modern medicine. Chinese herbal medicine has a long history, rich varieties, and accurate treatment effects. Hitherto, many Chinese herbal medicine studies have emerged to improve renal interstitial fibrosis. This paper reviews the mechanisms of renal interstitial fibrosis and recent studies on the disease intervention with Chinese herbal medicine through literature search, intend to reveal the importance of Chinese herbal medicine in renal interstitial fibrosis. The results show that Chinese herbal medicine can improve renal interstitial fibrosis, and the effects of Chinese herbal medicine on specific pathological mechanisms underlying renal interstitial fibrosis have been explored. Additionally, the limitations and advantages of Chinese herbal medicine in the treatment of renal interstitial fibrosis, possible research directions, and new targets of Chinese herbal medicine are discussed to provide a basis for studies of renal interstitial fibrosis.

G Protein-Coupled Receptor Kinase 2 as Novel Therapeutic Target in Fibrotic Diseases

G protein-coupled receptor kinase 2 (GRK2), an important subtype of GRKs, specifically phosphorylates agonist-activated G protein-coupled receptors (GPCRs). Besides, current research confirms that it participates in multiple regulation of diverse cells via a non-phosphorylated pathway, including interacting with various non-receptor substrates and binding partners. Fibrosis is a common pathophysiological phenomenon in the repair process of many tissues due to various pathogenic factors such as inflammation, injury, drugs, etc. The characteristics of fibrosis are the activation of fibroblasts leading to myofibroblast proliferation and differentiation, subsequent aggerate excessive deposition of extracellular matrix (ECM). Then, a positive feedback loop is occurred between tissue stiffness caused by ECM and fibroblasts, ultimately resulting in distortion of organ architecture and function. At present, GRK2, which has been described as a multifunctional protein, regulates copious signaling pathways under pathophysiological conditions correlated with fibrotic diseases. Along with GRK2-mediated regulation, there are diverse effects on the growth and apoptosis of different cells, inflammatory response and deposition of ECM, which are essential in organ fibrosis progression. This review is to highlight the relationship between GRK2 and fibrotic diseases based on recent research. It is becoming more convincing that GRK2 could be considered as a potential therapeutic target in many fibrotic diseases.