Curcumin analogue C66 attenuates obesity-induced renal injury by inhibiting chronic inflammation

Obesity-related glomerulopathy: recent advances in inflammatory mechanisms and related treatments

Obesity-related glomerulopathy, which is an obesity-triggered kidney damage, has become a significant threat to human health. Several studies have recently highlighted the critical role of inflammation in obesity-related glomerulopathy development. Additionally, excess adipose tissue and adipocytes in patients with obesity produce various inflammatory factors that cause systemic low-grade inflammation with consequent damage to vascular endothelial cells, exacerbating glomerular injury. Therefore, we conducted a comprehensive review of obesity-related glomerulopathy and addressed the critical role of obesity-induced chronic inflammation in obesity-related glomerulopathy pathogenesis and progression, which leads to tubular damage and proteinuria, ultimately impairing renal function. The relationship between obesity and obesity-related glomerulopathy is facilitated by a network of various inflammation-associated cells (including macrophages, lymphocytes, and mast cells) and a series of inflammatory mediators (such as tumor necrosis factor α, interleukin 6, leptin, adiponectin, resistin, chemokines, adhesion molecules, and plasminogen activator inhibitor 1) and their inflammatory pathways. Furthermore, we discuss a recently discovered relationship between micronutrients and obesity-related glomerulopathy inflammation and the important role of micronutrients in the body's anti-inflammatory response. Therefore, assessing these inflammatory molecules and pathways will provide a strong theoretical basis for developing therapeutic strategies based on anti-inflammatory effects to prevent or delay the onset of kidney injury.

Bicyclol alleviates obesity-induced renal injury by inhibiting JNK and NF-κB-mediated inflammation

Obesity is recognized as a major risk factor for chronic kidney disease (CKD), which is accompanied by increased renal lipid build-up, fibrosis, inflammation, apoptosis and pyroptosis. Bicyclol (BIC), a Chinese marketed hepatoprotective drug, has shown excellent anti-inflammatory, anti-fibrosis, anti-apoptotic, and lipid regulation effects in different animal models. In this study, we explored the role and mechanism of BIC in high-fat diet (HFD)-induced obesity-related nephropathy. Mice were fed with HFD for 24 weeks to develop obesity-related nephropathy, while mice in the BIC administration group were treated with BIC (50 mg/kg or 100 mg/kg, once every two days) at the last 12 weeks. We found that BIC treatment relieved the impairment of kidney structure and renal dysfunction caused by HFD. In addition, we found that BIC mitigated HFD-induced renal fibrosis, inflammation, apoptosis and pyroptosis by inhibiting JNK and NF-κB pathways. SV40-MES-13 cells treated with palmitate (PA) were used as the in vitro model. Our data show that BIC pre-administration relieved cellular damage caused by PA through suppressing JNK and NF-κB signaling pathways. In conclusion, we demonstrated that BIC attenuated obesity-induced renal injury by inhibiting chronic inflammation, fibrosis, apoptosis and pyroptosis via targeting JNK and NF-κB pathways. Our data suggested that BIC could be potentially used to prevent obesity-associated nephropathy, which warrants future investigation.

ERK/NF-kB/COX-2 Signaling Pathway Plays a Key Role in Curcumin Protection against Acetaminophen-Induced Liver Injury

Recent experimental studies have highlighted the beneficial effects of curcumin on liver injury induced by acetaminophen (APAP). However, the specific molecular mechanisms underlying curcumin's hepatoprotective effects against APAP-induced liver injury remain to be fully elucidated. This study aimed to investigate the therapeutic effect of curcumin on APAP-induced liver injury using a mouse model. In the experiment, mice were subjected to an intraperitoneal hepatotoxic dose of APAP (300 mg/kg) to induce hepatotoxicity. After 30 min of APAP administration, the mice were treated with different concentrations of curcumin (0, 10, 25, or 50 mg/kg). After 16 h, mice with hepatotoxicity showed elevated levels of serum alanine transaminase (ALT), aspartate transaminase (AST), hepatic myeloperoxidase (MPO), TNF-α, and IL-6, and decreased levels of glutathione (GSH). Moreover, there was an increased infiltration of neutrophils and macrophages following intraperitoneal injection of APAP. However, curcumin-treated mice displayed a pronounced reduction in serum ALT, AST, hepatic MPO, TNF-α, and IL-6 levels, coupled with a notable elevation in GSH levels compared to the APAP-treated hepatotoxic mice. Moreover, curcumin treatment led to reduced infiltration of neutrophils and macrophages. Additionally, curcumin inhibited the phosphorylation of ERK and NF-kB proteins while reducing the expression of cyclooxygenase-2 (COX-2). These findings highlight the hepatoprotective potential of curcumin against APAP-induced liver injury through the suppression of the ERK, NF-kB, and COX-2 signaling pathways.

Therapeutic Effects of Curcumin Derivatives against Obesity and Associated Metabolic Complications: A Review of In Vitro and In Vivo Studies

Obesity is a major cause of morbidity and mortality globally, increasing the risk for chronic diseases. Thus, the need to identify more effective anti-obesity agents has spurred significant interest in the health-promoting properties of natural compounds. Of these, curcumin, the most abundant and bioactive constituent of turmeric, possesses a variety of health benefits including anti-obesity effects. However, despite its anti-obesity potential, curcumin has demonstrated poor bioavailability, which limits its clinical applicability. Synthesizing curcumin derivatives, which are structurally modified analogs of curcumin, has been postulated to improve bioavailability while maintaining therapeutic efficacy. This review summarizes in vitro and in vivo studies that assessed the effects of curcumin derivatives against obesity and its associated metabolic complications. We identified eight synthetic curcumin derivatives that were shown to ameliorate obesity and metabolic dysfunction in diet-induced obese animal models, while five of these derivatives also attenuated obesity and associated metabolic complications in cell culture models. These curcumin derivatives modulated adipogenesis, lipid metabolism, insulin resistance, steatosis, lipotoxicity, inflammation, oxidative stress, endoplasmic reticulum stress, apoptosis, autophagy, fibrosis, and dyslipidemia to a greater extent than curcumin. In conclusion, the findings from this review show that compared to curcumin, synthetic curcumin derivatives present potential candidates for further development as therapeutic agents to modulate obesity and obesity-associated metabolic complications.

Small Ceria Nanoclusters with High ROS Scavenging Activity and Favorable Pharmacokinetic Parameters for the Amelioration of Chronic Kidney Disease

The over production of reactive oxygen species (ROS) plays a critical role in the progression of chronic kidney disease (CKD). Organic ROS scavengers currently used for CKD treatment do not satisfy low dosage and high efficiency requirements. Ceria nanomaterials featured with renewable ROS scavenging activity are potential candidates for CKD treatment. Herein, a method for the synthesis of ceria nanoclusters (NCs) featured with small size of ≈1.2 nm is reported. The synthesized NCs are modified by three hydrophilic ligands with different molecular weights, including succinic acid (SA), polyethylene glycol diacid 600 (PEG600), and polyethylene glycol diacid 2000 (PEG2000). The surface modified NCs exhibit excellent ROS scavenging activity due to the high Ce3+ /Ce4+ ratio in their crystal structures. Compared with bigger-sized ceria nanoparticles (NPs) (≈45 nm), NCs demonstrate smoother blood concentration-time curve, lower organ accumulation, and faster metabolic rate superiorities. The administration of NCs to CKD mice, especially PEG600 and PEG2000 modified NCs, can effectively inhibit oxidative stress, inflammation, renal fibrosis, and apoptosis in their kidneys. Due to these benefits, the constructed NCs can ameliorate the progression of CKD. These findings suggest that NCs is a potential redox nanomedicine for future clinical treatment of CKD.

Wen-Shen-Jian-Pi-Hua-Tan decoction protects against early obesity-related glomerulopathy by improving renal bile acid composition and suppressing lipogenesis, inflammation, and fibrosis

BACKGROUND

Obesity is an independent predictor of chronic kidney disease (CKD) development and may directly lead to kidney lesions such as obesity-related glomerulopathy (ORG) which might play a vital pathogenic role in obese patients with CKD. Wen-Shen-Jian-Pi-Hua-Tan decoction (WSHT) has been clinically used for the treatment of obesity and obesity-related metabolic diseases for years. However, the renoprotective effects and potential mechanism of action of WSHT against ORG remain unknown.

PURPOSE

This study aimed to explore the potential effect of WSHT on ORG and reveal its mechanisms in high-fat diet (HFD)-induced obese rats.

METHODS

An animal model of early stage ORG was established using HFD-induced obese rats. After treatment with WSHT for 6 weeks, an integrated metabolomics and molecular biology strategy was utilized to illustrate the effects and mechanism of WSHT on ORG. First, UPLC-ESI-MS/MS-based targeted metabolomics was used to analyze renal bile acid (BA) levels. Biochemical, histological, and immunofluorescence assays; electron microscopy; and western blotting were performed to evaluate the efficacy of WSHT against ORG and its underlying mechanisms in vivo.

RESULTS

Our results showed that an HFD led to hyperlipidemia, proteinuria, renal lipid deposition, effacement of podocyte foot processes, and increased expression of proinflammatory factors and profibrotic growth factors in ORG rats. In addition, an HFD decreased the levels of renal BAs such as cholic acid, chenodeoxycholic acid, and lithocholic acid. After 6 weeks of treatment, WSHT markedly attenuated dyslipidemia and reduced body, kidney and epididymal fat weights in ORG rats. WSHT also significantly increased BA levels, suggesting that it altered BA composition; the effects of BAs are closely associated with farnesoid X receptor (FXR) activation. WSHT alleviated fat accumulation, podocyte loss and proteinuria, and reduced the expression of proinflammatory cytokines and profibrotic growth factors in the kidneys of ORG rats. Finally, WSHT remarkably upregulated the renal expression of FXR and salt-induced kinase 1 and blocked the renal expression of sterol regulatory element-binding protein-1c and its target genes.

CONCLUSION

WSHT attenuated early renal lesions in ORG rats by improving renal BA composition and suppressing lipogenesis, inflammation and fibrosis. This study develops a new way to alleviate obesity-induced renal damages.

Curcumin analog C66 alleviates inflammatory colitis by inhibiting the activation of NF-κB

BACKGROUND

The pathogenesis of inflammatory bowel disease (IBD) remains unclear. C66, a derivative of curcumin, reportedly exerts anti-inflammatory, antifibrotic and anti-apoptotic effects by targeting the JNK pathway. However, the effect of C66 against IBD is not clear. In this study, we aimed to investigate the effect of C66 against IBD.

METHODS

C57BL/6J mice were treated with 2.5% DSS for 7 days, and then administered water for 3 days to develop the IBD mouse model. A mouse intestinal epithelial cell line, MODE-K, stimulated by lipopolysaccharide (LPS) was used as the in vitro model. The therapeutic effects of C66 were evaluated and the pharmacological mechanisms were explored.

RESULTS

Compared to the model group, C66 treatment significantly reduced colitis-associated damage, including a decrease in disease activity index (DAI), a higher body weight and longer colon. In addition, the infiltration of distal inflammatory cells, loss of crypt tissues, and destruction of epithelial cells were reduced in C66-treated group. In addition, C66 treatment reduced fibrotic areas and inflammatory responses in the colon tissues, leading to increased epithelial cell proliferation and decreased apoptosis in colon. Furthermore, C66 treatment decreased the levels of p-JNK and p-P65, indicating that C66 inhibits the activation of the JNK and NF-κB signaling pathways induced by DSS in colon tissues. Finally, in vitro data show that C66 inhibited LPS-induced inflammation and apoptosis in small intestinal epithelial cells.  CONCLUSIONS: The curcumin analog C66 exhibits its anti-inflammatory effect by inhibiting the DSS-induced activation of JNK/NF-κB signaling pathways. C66 may be a potential candidate for the treatment of IBD.

Curcumin intervention during progressive fibrosis controls inflammatory cytokines and the fibrinolytic system in pulmonary fibrosis

Persistent injuries and chronic inflammation paired with dysregulated healing process in the lungs leads to scarring and stiffening of the tissue leading to a condition called pulmonary fibrosis. There is no efficacious therapy against the condition because of the poorly understood pathophysiology of the disease. Curcumin is well known anti-inflammatory natural compound and is shown to have beneficial effects in many diseases. It is also reported to show antifibrotic activities in pulmonary fibrosis. There are evidences that fibrinolytic system plays a crucial role in the development of pulmonary fibrosis. We aimed to see whether curcumin could regulate inflammation and fibrinolysis in murine model of pulmonary fibrosis. We prepared BLM induced pulmonary fibrosis model by administering BLM at a dose of 2 mg/ kg bodyweight. Curcumin (75 mg/kg body wt) was instilled intraperitoneally on different time points. The effect of curcumin on inflammatory cytokines and fibrinolytic system was studied using molecular biology techniques like RT-PCR, western blot and immunohistochemistry/immunofluorescence. We observed that BLM brought changes in the expressions of components in the fibrinolytic system, i.e. BLM favoured fibrin deposition by increasing the expression of PAI-1 (plasminogen activator inhibitor) and decreasing the expression of uPA (Urokinase plasminogen activator) and uPAR (Urokinase plasminogen activator receptor). We also demonstrate that curcumin could restore the normal expression of fibrinolytic components, uPA, uPAR and PAI-1. Curcumin could also minimize the expression of key enzymes in tissue remodeling in pulmonary fibrosis, MMP-2 and MMP-9, which were elevated in the BLM treated group. Our data suggest that curcumin exerts an anti-inflammatory and antifibrotic effect in lungs. We highlight curcumin as a feasible adjuvant therapy option against pulmonary fibrosis.

Curcumin Derivative C66 Suppresses Pancreatic Cancer Progression through the Inhibition of JNK-Mediated Inflammation

Pancreatic adenocarcinoma is by far the deadliest type of cancer. Inflammation is one of the important risk factors in tumor development. However, it is not yet clear whether deterioration in pancreatic cancer patients is related to inflammation, as well as the underlying mechanism. In addition, JNK is abnormally activated in pancreatic cancer cells and the JNK inhibitor C66 reduces the inflammatory microenvironment in the tumor. Therefore, the aim of this study was to evaluate the role of C66 in the proliferation and migration of pancreatic cancer. Our results showed that various inflammatory cytokines, such as IL-1β, IL-6, IL-8, and IL-15, were more expressed in pancreatic cancer than in the matching normal tissue. Furthermore, C66, a curcumin analogue with good anti-inflammatory activity, inhibited the proliferation and migration of pancreatic cancer cells in a dose-dependent manner, and effectively inhibited the expression of the above inflammatory factors. Our previous research demonstrated that C66 prevents the inflammatory response by targeting JNK. Therefore, in this study, JNK activity in pancreatic cancer cells was investigated, revealing that JNK was highly activated, and the treatment with C66 inhibited the phosphorylation of JNK. Next, shJNK was used to knockdown JNK expression in pancreatic cancer cells to further confirm the role of JNK in the proliferation and migration of this tumor, as well as in the inflammatory tumor microenvironment (TME). The results demonstrated that JNK knockdown could significantly inhibit the proliferation and migration of pancreatic cancer. Moreover, the low JNK expression in pancreatic cancer cells significantly inhibited the expression of various inflammatory factors. These results indicated that C66 inhibited the progression of pancreatic cancer through the inhibition of JNK-mediated inflammation.

Anti-Inflammatory Effects of Curcumin in the Inflammatory Diseases: Status, Limitations and Countermeasures

Curcumin is a natural compound with great potential for disease treatment. A large number of studies have proved that curcumin has a variety of biological activities, among which anti-inflammatory effect is a significant feature of it. Inflammation is a complex and pervasive physiological and pathological process. The physiological and pathological mechanisms of inflammatory bowel disease, psoriasis, atherosclerosis, COVID-19 and other research focus diseases are not clear yet, and they are considered to be related to inflammation. The anti-inflammatory effect of curcumin can effectively improve the symptoms of these diseases and is expected to be a candidate drug for the treatment of related diseases. This paper mainly reviews the anti-inflammatory effect of curcumin, the inflammatory pathological mechanism of related diseases, the regulatory effect of curcumin on these, and the latest research results on the improvement of curcumin pharmacokinetics. It is beneficial to the further study of curcumin and provides new ideas and insights for the development of curcumin anti-inflammatory preparations.

Obesity-Related Glomerulopathy: From Mechanism to Therapeutic Target

Obesity-related glomerulopathy (ORG) is a secondary glomerular disease caused by obesity, with clinical manifestations such as proteinuria and glomerulomegaly. Currently, the high incidence of obesity brings a change in the spectrum of kidney diseases across the globe, including China. ORG has become another important secondary nephropathy leading to end-stage renal disease (ESRD), and its incidence has increased significantly. This trend is bound to bring about a serious socioeconomic burden. Therefore, it is urgent to study its pathogenesis and intervention measures. Currently, the occurrence and development mechanisms in ORG are complicated by many factors, which are still unclear. In the past 20 years, with the continuous intensive research on mechanisms such as hypoxia in the metabolic process, immune inflammation, and pyroptosis, there have been new advances in the mechanism of ORG, especially the important role of inflammation in podocyte injury and its impact on the progress of ORG. Here, we briefly review the possible pathogenic role of the inflammasome in the podocyte damage in ORG and summarize the possible therapeutical strategies targeting inflammasome.