Hyperforin regulates renal fibrosis via targeting the PI3K-AKT/ICAM1 axis

Targeted delivery of type I TGF-β receptor-mimicking peptide to fibrotic kidney for improving kidney fibrosis therapy via enhancing the inhibition of TGF-β1/Smad and p38 MAPK pathways

Renal fibrosis is a representative pathological feature of various chronic kidney diseases, and efficient treatment is needed. Interstitial myofibroblasts are a key driver of kidney fibrosis, which is dependent on the binding of TGF-β1 to type I TGF-β receptor (TβRI) and TGF-β1-related signaling pathways. Therefore, attenuating TGF-β1 activity by competing with TGF-β1 in myofibroblasts is an ideal strategy for treating kidney fibrosis. Recently, a novel TβRI-mimicking peptide RIPΔ demonstrated a high affinity for TGF-β1. Thus, it could be speculated that RIPΔ may be used for anti-fibrosis therapy. Platelet-derived growth factor β receptor (PDGFβR) is highly expressed in fibrotic kidney. In this study, we found that target peptide Z-RIPΔ, which is RIPΔ modified with PDGFβR-specific affibody ZPDGFβR, was specifically and highly taken up by TGF-β1-activated NIH3T3 fibroblasts. Moreover, Z-RIPΔ effectively inhibited the myofibroblast proliferation, migration and fibrosis response in vitro. In vivo and ex vivo experiments showed that Z-RIPΔ specifically targeted fibrotic kidney, improved the damaged renal function, and ameliorated kidney histopathology and renal fibrosis in UUO mice. Mechanistic studies showed that Z-RIPΔ hold the stronger inhibition of the TGF-β1/Smad and TGF-β1/p38 pathways than unmodified RIPΔ in vitro and in vivo. Furthermore, systemic administration of Z-RIPΔ to UUO mice led to minimal toxicity to major organs. Taken together, RIPΔ modified with ZPDGFβR increased its therapeutic efficacy and reduced its systemic toxicity, making it a potential candidate for targeted therapy for kidney fibrosis.

Fibrosis in Chronic Kidney Disease: Pathophysiology and Therapeutic Targets

Chronic kidney disease (CKD) is a slowly progressive condition characterized by decreased kidney function, tubular injury, oxidative stress, and inflammation. CKD is a leading global health burden that is asymptomatic in early stages but can ultimately cause kidney failure. Its etiology is complex and involves dysregulated signaling pathways that lead to fibrosis. Transforming growth factor (TGF)-β is a central mediator in promoting transdifferentiation of polarized renal tubular epithelial cells into mesenchymal cells, resulting in irreversible kidney injury. While current therapies are limited, the search for more effective diagnostic and treatment modalities is intensive. Although biopsy with histology is the most accurate method of diagnosis and staging, imaging techniques such as diffusion-weighted magnetic resonance imaging and shear wave elastography ultrasound are less invasive ways to stage fibrosis. Current therapies such as renin-angiotensin blockers, mineralocorticoid receptor antagonists, and sodium/glucose cotransporter 2 inhibitors aim to delay progression. Newer antifibrotic agents that suppress the downstream inflammatory mediators involved in the fibrotic process are in clinical trials, and potential therapeutic targets that interfere with TGF-β signaling are being explored. Small interfering RNAs and stem cell-based therapeutics are also being evaluated. Further research and clinical studies are necessary in order to avoid dialysis and kidney transplantation.

Isolation and target identification of anti-renal fibrosis compounds from Cordyceps militaris

Four undescribed compounds including one aromatic glucoside derivative, cordyceglycoside A (1), one new isoleucine derivative inner salt, cordycepisosalt A (2), a rare four-membered lactam, cinerealactam B (3), and one sesquiterpene derivative, cordycepsetp A (4), together with six known compounds were isolated from Cordyceps militaris. The structures including absolute configurations of these new compounds, were unambiguously elucidated by spectroscopic data analysis and single crystal X-ray diffraction. Biological evaluation of compounds 1-4 showed that 3 displays anti-renal fibrotic activities in TGF-β1 induced NRK-52e cells. Furthermore, DARTS coupled with LC-MS/MS analysis was used to identify candidate target proteins for 3. Subsequently, C1qbp knockdown using siRNA allowed us to validate the target protein of 3.