Jaechan Leem

Cisplatin (CDDP) is a cornerstone chemotherapeutic drug, yet its efficacy is frequently compromised by renal toxicity, primarily manifesting as acute kidney injury (AKI). Magnolol (MG) is a polyphenol from Magnolia officinalis and has been widely documented for its pronounced antioxidant and anti-inflammatory properties. This study evaluated the renoprotective effects of MG in a murine model of CDDP-induced AKI. Male C57BL/6 mice received MG (20 mg/kg) via daily intraperitoneal injection for four consecutive days, starting one day before a single CDDP injection. MG significantly reduced the serum concentrations of blood urea nitrogen and creatinine. Histopathological assessment revealed attenuated tubular damage and reduced expression of tubular injury markers. MG inhibited pro-inflammatory cytokines at both systemic and renal levels, alleviated endoplasmic reticulum stress, and suppressed activation of mitogen-activated protein kinase signaling pathways. Apoptotic damage was mitigated, as shown by the fewer TUNEL-positive cells and lowered expression of pro-apoptotic markers. In parallel, ferroptotic processes were alleviated through downregulation of pro-ferroptotic proteins and preservation of key antioxidant regulators. Importantly, MG restored nuclear factor erythroid 2-related factor 2 activity and upregulated downstream antioxidant effectors. These findings highlight the multi-targeted renoprotective actions of MG and support its possible utility as a therapeutic agent to prevent CDDP-induced renal injury.

Renal fibrosis is a key factor in the progression of chronic kidney disease (CKD), and current treatments remain inadequate. In this study, we investigated the therapeutic effects of cynaroside (Cyn), a natural flavonoid, in a mouse model of renal fibrosis induced by unilateral ureteral obstruction. Cyn treatment significantly ameliorated tubular injury and interstitial fibrosis while improving renal function. Mechanistically, Cyn inhibited the expression of fibrosis-related proteins and suppressed Smad2/3 phosphorylation. Additionally, Cyn reduced myofibroblast accumulation by inhibiting epithelial-mesenchymal transition, as indicated by increased E-cadherin expression and decreased levels of mesenchymal markers. Cyn also reduced oxidative stress by downregulating the prooxidant enzyme NADPH oxidase 4 and restoring antioxidant enzymes. Furthermore, Cyn attenuated ferroptosis by regulating key proteins, including acyl-CoA synthetase long-chain family member 4, transferrin receptor 1, and glutathione peroxidase 4, while also restoring glutathione levels. Cyn alleviated endoplasmic reticulum stress, as evidenced by the downregulation of key markers such as glucose-regulated protein 78 and activating transcription factor 6, and reduced inflammation, as confirmed by decreased macrophage infiltration and lower cytokine production. Overall, Cyn demonstrated broad protective effects against renal fibrosis by modulating oxidative stress, ferroptosis, ER stress, and inflammation, positioning it as a potential therapeutic agent for CKD management.

Background: Cisplatin (CDDP) is a cornerstone chemotherapeutic agent for many solid tumors, but its clinical use is severely limited by dose-dependent nephrotoxicity, which results in acute kidney injury (AKI) in a significant proportion of patients. CDDP-induced AKI involves interconnected mechanisms, including inflammation, oxidative stress, and tubular cell death. In this study, we aimed to investigate the renoprotective effects of esculetin (ES), a natural antioxidant coumarin, in a murine model of CDDP-induced AKI. Methods: Male C57BL/6 mice (8–10 weeks) received a single intraperitoneal injection of CDDP (20 mg/kg) with or without ES (40 mg/kg/day, oral gavage). Renal function, histopathology, and molecular markers of inflammation, oxidative stress, mitogen-activated protein kinase (MAPK) activation, endoplasmic reticulum (ER) stress, apoptosis, and ferroptosis were assessed by standard biochemical, histological, and immunoblotting techniques. Results: ES significantly reduced CDDP-induced elevations in serum creatinine and blood urea nitrogen, preserved renal structure, and decreased histological injury scores. Molecular analyses showed that ES suppressed the production of systemic and renal proinflammatory cytokines and inhibited the expression of chemokines and adhesion molecules. ES also suppressed the phosphorylation of extracellular signal-regulated kinase 1/2 and p38 MAPKs, mitigating stress-induced inflammatory and apoptotic signaling. Additionally, ES treatment reduced the expression of unfolded protein response markers, such as C/EBP homologous protein, which is indicative of alleviated ER stress. Oxidative injury was reduced, as evidenced by lower malondialdehyde and 4-hydroxynonenal levels and restored glutathione content. Importantly, ES mitigated ferroptosis, as demonstrated by decreased expression of pro-ferroptotic markers and preservation of anti-ferroptotic mediators, including glutathione peroxidase 4 and solute carrier family 7 member 1. Conclusion: Collectively, our findings provide the first in vivo evidence that ES robustly protects against CDDP-induced AKI by simultaneously targeting oxidative stress, inflammation, MAPK, and ER stress pathways, apoptosis, and ferroptosis. These results highlight ES as a potential candidate for preventing CDDP-induced nephrotoxicity.

Chronic kidney disease (CKD) progresses through mechanisms involving inflammation, fibrosis, and oxidative stress, leading to the gradual structural and functional deterioration of the kidneys. Tormentic acid (TA), a triterpenoid compound with known anti-inflammatory and antioxidant properties, shows significant potential in counteracting these pathological processes. This study explored the protective role of TA in a unilateral ureteral obstruction (UUO)-induced CKD model. Mice received TA through intraperitoneal injections at a dosage of 5 mg/kg per day for 8 consecutive days, commencing a day before the UUO procedure. The TA treatment significantly improved both structural and functional kidney injury. It suppressed cytokine expression and reduced immune cell infiltration, inhibited the activation of the mitogen-activated protein kinase cascade, and alleviated endoplasmic reticulum stress. Moreover, TA displayed potent anti-fibrotic effects by reversing epithelial-to-mesenchymal transition and inhibiting Smad2/3 activation, reducing extracellular matrix deposition. TA also mitigated oxidative stress by attenuating lipid peroxidation and boosting antioxidant defenses. Additionally, it inhibited apoptosis and ferroptosis by reducing oxidative stress and modulating key cell death markers. Collectively, these findings indicate that TA provides comprehensive renoprotection in the UUO model by effectively targeting inflammation, fibrosis, oxidative stress, and tubular cell death in CKD progression.

Cisplatin, a platinum-based chemotherapeutic, is effective against various solid tumors, but its use is often limited by its nephrotoxic effects. This study evaluated the protective effects of trametinib, an FDA-approved selective inhibitor of mitogen-activated protein kinase kinase 1/2 (MEK1/2), against cisplatin-induced acute kidney injury (AKI) in mice. The experimental design included four groups, control, trametinib, cisplatin, and a combination of cisplatin and trametinib, each consisting of eight mice. Cisplatin was administered intraperitoneally at a dose of 20 mg/kg to induce kidney injury, while trametinib was administered via oral gavage at 3 mg/kg daily for three days. Assessments were conducted 72 h after cisplatin administration. Our results demonstrate that trametinib significantly reduces the phosphorylation of MEK1/2 and extracellular signal-regulated kinase 1/2 (ERK1/2), mitigated renal dysfunction, and ameliorated histopathological abnormalities. Additionally, trametinib significantly decreased macrophage infiltration and the expression of pro-inflammatory cytokines in the kidneys. It also lowered lipid peroxidation by-products, restored the reduced glutathione/oxidized glutathione ratio, and downregulated NADPH oxidase 4. Furthermore, trametinib significantly inhibited both apoptosis and necroptosis in the kidneys. In conclusion, our data underscore the potential of trametinib as a therapeutic agent for cisplatin-induced AKI, highlighting its role in reducing inflammation, oxidative stress, and tubular cell death.

Atopic dermatitis (AD), marked by intense itching and eczema-like lesions, is a globally increasing chronic skin inflammation. Kahweol, a diterpene that naturally occurs in coffee beans, boasts anti-inflammatory, antioxidative, and anti-cancer properties. This research explores the anti-inflammatory action of kahweol on HaCaT human keratinocytes stimulated by tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ), focusing on key signal transduction pathways. Our results demonstrate that kahweol markedly reduces the production of IL-1β, IL-6, C-X-C motif chemokine ligand 8, and macrophage-derived chemokine in TNF-α/IFN-γ-activated HaCaT cells. Furthermore, it curtails the phosphorylation of key proteins in the mitogen-activated protein kinase (MAPK) pathways, including c-Jun N-terminal kinase, extracellular signal-regulated kinase, and p38. Additionally, kahweol impedes the phosphorylation and nuclear translocation of the NF-κB p65 subunit and constrains its DNA-binding capability. It also hampers the phosphorylation, nuclear translocation, and DNA-binding activities of signal transducer and activator of transcription 1 (STAT1) and STAT3. Collectively, these findings suggest that kahweol hinders the generation of cytokines and chemokines in inflamed keratinocytes by inhibiting the MAPK, NF-κB, and STAT cascades. These insights position kahweol as a promising agent for dermatological interventions, especially in managing inflammatory skin conditions such as AD.

Non-alcoholic steatohepatitis (NASH) is becoming an increasingly serious global health threat, distinguished by hepatic lipid accumulation, inflammation, and fibrosis. There is a lack of approved pharmaceutical interventions for this disease, highlighting the urgent need for effective treatment. This study explores the hepatoprotective potential of 6-shogaol, a natural compound derived from ginger, in a methionine- and choline-deficient (MCD) dietary mouse model of NASH. Male C57BL/6J mice were subjected to the MCD diet for 4 weeks to induce NASH, with concurrent intraperitoneal administration of 6-shogaol (20 mg/kg) three times a week. While 6-shogaol did not impact body weight, liver weight, or hepatic lipid accumulation, it effectively mitigated liver injury, inflammation, and fibrosis in MCD diet-fed mice. Mechanistically, 6-shogaol inhibited lipid and DNA oxidation, restored hepatic glutathione levels, and regulated the expression of pro-oxidant and antioxidant enzymes. Furthermore, 6-shogaol inhibited apoptosis and necroptosis, as indicated by a decrease in TUNEL-stained cells and downregulation of apoptosis- and necroptosis-associated proteins. Additionally, 6-shogaol alleviated endoplasmic reticulum (ER) stress, as demonstrated by decreased expression of molecules associated with unfolded protein response pathways. These findings underscore the potential of 6-shogaol as a therapeutic intervention for NASH by targeting pathways related to oxidative stress, cell death, and ER stress.