Emodin attenuates high glucose-induced TGF-β1 and fibronectin expression in mesangial cells through inhibition of NF-κB pathway

Advances in oxidative stress in pathogenesis of diabetic kidney disease and efficacy of TCM intervention

Diabetic kidney disease (DKD) is a common complication of diabetes and has become the leading cause of end-stage kidney disease. The pathogenesis of DKD is complicated, and oxidative stress is considered as a core of DKD onset. High glucose can lead to increased production of reactive oxygen species (ROS) via the polyol, PKC, AGE/RAGE and hexosamine pathways, resulting in enhanced oxidative stress response. In this way, pathways such as PI3K/Akt, TGF-β1/p38-MAPK and NF-κB are activated, inducing endothelial cell apoptosis, inflammation, autophagy and fibrosis that cause histologic and functional abnormalities of the kidney and finally result in kidney injury. Presently, the treatment for DKD remains an unresolved issue. Traditional Chinese medicine (TCM) has unique advantages for DKD prevention and treatment attributed to its multi-target, multi-component, and multi-pathway characteristics. Numerous studies have proved that Chinese herbs (e.g., Golden Thread, Kudzuvine Root, Tripterygium glycosides, and Ginseng) and patent medicines (e.g., Shenshuaining Tablet, Compound Rhizoma Coptidis Capsule, and Zishen Tongluo Granule) are effective for DKD treatment. The present review described the role of oxidative stress in DKD pathogenesis and the effect of TCM intervention for DKD prevention and treatment, in an attempt to provide evidence for clinical practice.

Advances in the pharmacological effects and molecular mechanisms of emodin in the treatment of metabolic diseases

Rhubarb palmatum L., Polygonum multijiorum Thunb., and Polygonum cuspidatum Sieb. Et Zucc. are traditional Chinese medicines that have been used for thousands of years. They are formulated into various preparations and are widely used. Emodin is a traditional Chinese medicine monomer and the main active ingredient in Rhubarb palmatum L., Polygonum multijiorum Thunb., and Polygonum cuspidatum Sieb. Et Zucc. Modern research shows that it has a variety of pharmacological effects, including promoting lipid and glucose metabolism, osteogenesis, and anti-inflammatory and anti-autophagy effects. Research on the toxicity and pharmacokinetics of emodin can promote its clinical application. This review aims to provide a basis for further development and clinical research of emodin in the treatment of metabolic diseases. We performed a comprehensive summary of the pharmacology and molecular mechanisms of emodin in treating metabolic diseases by searching databases such as Web of Science, PubMed, ScienceDirect, and CNKI up to 2023. In addition, this review also analyzes the toxicity and pharmacokinetics of emodin. The results show that emodin mainly regulates AMPK, PPAR, and inflammation-related signaling pathways, and has a good therapeutic effect on obesity, hyperlipidemia, non-alcoholic fatty liver disease, diabetes and its complications, and osteoporosis. In addition, controlling toxic factors and improving bioavailability are of great significance for its clinical application.

A proteoglycan isolated from Ganoderma lucidum attenuates diabetic kidney disease by inhibiting oxidative stress-induced renal fibrosis both in vitro and in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Ganoderma lucidum (G. lucidum) was regarded as "miraculous herb" by the Chinese and recorded detailly in the "Shen Nong Ben Cao Jing" as a tonic to improve health and prolong life. A proteoglycan (namely, FYGL) was extracted from Ganoderma lucidum, which was a water-soluble hyperbranched proteoglycan, and was found to be able to protect pancreatic tissue against oxidative stress damage.

AIM OF THE STUDY

Diabetic kidney disease (DKD) is a complication of diabetes, but the effective treatment is still lack. Chronic hyperglycemia in diabetic patients induce the accumulation of ROS, which injure the renal tissue and lead to the renal dysfunction. In this work, the efficacy and target mechanics of FYGL on diabetic renal function were investigated.

MATERIALS AND METHODS

In the present study, the mechanism of the reno-protection of FYGL was analyzed on diabetic db/db mice and rat glomerular mesangial cells (HBZY-1) induced by high glucose (HG) with palmitate (PA) (HG/PA). In vitro, the levels of reactive oxygen species (ROS), malondialdehyde (MDA) and superoxide dismutase (SOD) were evaluated by commercial kits. the expressions of NOX1 and NOX4, phosphorylation of MAPK and NF-κB, and pro-fibrotic proteins were measured by Western blot. In vivo, diabetic db/db mice were gavaged with FYGL for 8 weeks, body weight and fasting blood glucose (FBG) were tested weekly. On 8th week, the serum, urine and renal tissue were collected for glucose tolerance test (OGTT), redox indicator (SOD, CAT, GSH and MDA), lipid metabolism (TC, TG, LDL and HDL), blood urea nitrogen (BUN), serum creatinine (Scr), uric acid (UA), 8-oxo-deoxyguanosine (8-OHdG), and the changes of histopathology and expression of collagen IV and AGEs.

RESULTS

The results in vitro showed that FYGL significantly inhibited the HG/PA-induced HBZY-1 cells proliferation, ROS generation, MDA production, promoted SOD activity, and suppressed NOX1, NOX4, MAPK, NF-κB, and pro-fibrotic proteins expression. In addition, FYGL markedly alleviated blood glucose, antioxidant activity and lipid metabolism, improved renal functions, and relieved renal histopathological abnormalities, especially renal fibrosis.

CONCLUSIONS

The antioxidant activity of FYGL can reduce ROS caused by diabetes and protect renal from oxidative stress-induced dysfunction, thereby improving renal function. This study shows that FYGL has the potential to treat diabetic kidney disease.

Integrin β1/Cell Surface GRP78 Complex Regulates TGFβ1 and Its Profibrotic Effects in Response to High Glucose

Diabetic kidney disease (DKD) is the leading cause of kidney failure worldwide. Characterized by overproduction and accumulation of extracellular matrix (ECM) proteins, glomerular sclerosis is its earliest manifestation. High glucose (HG) plays a central role by increasing matrix production by glomerular mesangial cells (MC). We previously showed that HG induces translocation of GRP78 from the endoplasmic reticulum to the cell surface (csGRP78), where it acts as a signaling molecule to promote intracellular profibrotic FAK/Akt activation. Here, we identify integrin β1 as a key transmembrane signaling partner for csGRP78. We show that it is required for csGRP78-regulated FAK/Akt activation in response to HG, as well as downstream production, secretion and activity of the well characterized profibrotic cytokine transforming growth factor β1 (TGFβ1). Intriguingly, integrin β1 also itself promotes csGRP78 translocation. Furthermore, integrin β1 effects on cytoskeletal organization are not required for its function in csGRP78 translocation and signaling. These data together support an important pathologic role for csGRP78/integrin β1 in mediating key profibrotic responses to HG in kidney cells. Inhibition of their interaction will be further evaluated as a therapeutic target to limit fibrosis progression in DKD.

Sodium–glucose cotransporter-2 inhibitor alleviated atrial remodeling in STZ-induced diabetic rats by targeting TLR4 pathway

Purpose

The mechanism of sodium–glucose cotransporter-2 inhibitor (SGLT-2i) reducing the incidence of atrial fibrillation remains unclear. We hypothesize that sodium–glucose cotransporter-2 inhibitor alleviated atrial remodeling in STZ-induced diabetic rats by targeting TLR4 pathway.

Methods

A total of 42 rats were randomly assigned into three groups: control group (CON group); diabetes group (DM group): diabetes mellitus rats were established by 65 mg/kg streptozotocin (STZ) intraperitoneal injection; and diabetes + dapagliflozin group (DM + DAPA group): diabetic rats were given DAPA gavage administration (DAPA 2mg/kg/d for 4 weeks by gavage administration), 14 rats in each group. Epicardial multiple-lead recording and intracardiac electrophysiology studies were performed to investigate the electrical remodeling in the heart and the atrial fibrillation inducibility in each group. Western blot analysis and real-time PCR were used to determine the protein and mRNA expression of toll-like receptor 4 (TLR4), interleukin receptor-associated kinase 1 (IRAK1), tumor necrosis factor receptor-associated factor 6 (TRAF6), nuclear factor-kappa B (NF-κB), and type I collagen (collagen I).

Results

Compared with rats in CON group, rats in DM group showed marked myocardial fibrosis, ectopic pacing excitement, reduced conduction velocity, decreased cardiac function. TLR4/IRAK1/TRAF6/NF-κB, collagen I proteins expressions and incidence of atrial fibrillation (27.3%) were increased in DM group. Parts of these changes were reversed by treatment of DAPA. Incidence of atrial fibrillation was decreased in DM + DAPA group (2.8%).

Conclusions

SGLT-2i dapagliflozin may prevent diabetic rats' atrial remodeling and reduce the inducibility of atrial fibrillation partly by targeting TLR4/IRAK1/TRAF6/NF-κB inflammatory pathway.

The progress and prospect of natural components in rhubarb (Rheum ribes L.) in the treatment of renal fibrosis

Background: Renal fibrosis is a key pathological change that occurs in the progression of almost all chronic kidney diseases . CKD has the characteristics of high morbidity and mortality. Its prevalence is increasing each year on a global scale, which seriously affects people’s health and quality of life. Natural products have been used for new drug development and disease treatment for many years. The abundant natural products in R. ribes L. can intervene in the process of renal fibrosis in different ways and have considerable therapeutic prospects.

Purpose: The etiology and pathology of renal fibrosis were analyzed, and the different ways in which the natural components of R. ribes L. can intervene and provide curative effects on the process of renal fibrosis were summarized. Methods: Electronic databases, such as PubMed, Life Science, MEDLINE, and Web of Science, were searched using the keywords ‘R. ribes L.’, ‘kidney fibrosis’, ‘emodin’ and ‘rhein’, and the various ways in which the natural ingredients protect against renal fibrosis were collected and sorted out.

Results: We analyzed several factors that play a leading role in the pathogenesis of renal fibrosis, such as the mechanism of the TGF-β/Smad and Wnt/β-catenin signaling pathways. Additionally, we reviewed the progress of the treatment of renal fibrosis with natural components in R. ribes L. and the intervention mechanism of the crucial therapeutic targets.

Conclusion: The natural components of R. ribes L. have a wide range of intervention effects on renal fibrosis targets, which provides new ideas for the development of new anti-kidney fibrosis drugs.

Suitability of Banana and Plantain Fruits in Modulating Neurodegenerative Diseases: Implicating the In Vitro and In Vivo Evidence from Neuroactive Narratives of Constituent Biomolecules

Active principles in plant-based foods, especially staple fruits, such as bananas and plantains, possess inter-related anti-inflammatory, anti-apoptotic, antioxidative, and neuromodulatory activities. Neurodegenerative diseases affect the functionality of the central and peripheral nervous system, with attendant cognitive deficits being hallmarks of these conditions. The dietary constitution of a wide range of bioactive compounds identified in this review further iterates the significance of the banana and plantain in compromising, halting, or preventing the pathological mechanisms of neurological disorders. The neuroprotective mechanisms of these biomolecules have been identified by using protein expression regulation and specific gene/pathway targeting, such as the nuclear and tumor necrosis factors, extracellular signal-regulated and mitogen-activated protein kinases, activator protein-1, and the glial fibrillary acidic protein. This review establishes the potential double-edged neuro-pharmacological fingerprints of banana and plantain fruits in their traditionally consumed pulp and less utilized peel component for human nutrition.

Promoting Plant-Based Therapies for Chronic Kidney Disease

Chronic kidney disease (CKD) is debilitating, increasing in incidence worldwide, and a financial and social burden on health systems. Kidney failure, the final stage of CKD, is life-threatening if untreated with kidney replacement therapies. Current therapies using commercially-available drugs, such as angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers and calcium channel blockers, generally only delay the progression of CKD. This review article focuses on effective alternative therapies to improve the prevention and treatment of CKD, using plants or plant extracts. Three mechanistic processes that are well-documented in CKD pathogenesis are inflammation, fibrosis, and oxidative stress. Many plants and their extracts are already known to ameliorate kidney dysfunction through antioxidant action, with subsequent benefits on inflammation and fibrosis. In vitro and in vivo experiments using plant-based therapies for pre-clinical research demonstrate some robust therapeutic benefits. In the CKD clinic, combination treatments of plant extracts with conventional therapies that are seen as relatively successful currently may confer additive or synergistic renoprotective effects. Therefore, the aim of recent research is to identify, rigorously test pre-clinically and clinically, and avoid any toxic outcomes to obtain optimal therapeutic benefit from medicinal plants. This review may prove to be a filtering tool to researchers into complementary and alternative medicines to find out the current trends of using plant-based therapies for the treatment of kidney diseases, including CKD.

Effects of Psoralea corylifolia L. seed extract on AGEs-induced cell proliferation and fibrotic factor expression in mesangial cells

Diabetic nephropathy is a microvascular complication of diabetes that is characterized by mesangial expansion and thickening of the glomerular basement membrane. The production of advanced glycation end products (AGEs) increases in diabetic patients. Activation of the receptor of AGE (RAGE) signaling pathway induces mesangial expansion via the reactive oxygen species (ROS)-mediated production of pro-inflammatory and extracellular matrix molecules. The Psoralea corylifolia L. seed (PCS) is a widely used herbal medicine with various biological activities. The current study investigated the effect of PCS extract on mesangial cell proliferation and the RAGE signaling pathway in SV40 MES 13 cells. SV40 MES 13 cells were harvested after treatment with various concentrations of PCS extract at 10 µg/ml AGEs for 24 h. The results revealed that the PCS extract inhibited AGEs-induced mesangial cell proliferation and cyclin protein expression in a concentration-dependent manner. In addition, the AGEs-induced expression of fibrotic factors, such as transforming growth factor β, fibronectin and collagen, was reduced in mesangial cells after exposure to the PCS extract. The PCS extract also reduced RAGE expression and inhibited the expression of its downstream signaling pathways, such as NADPH oxidase, intracellular ROS and phospho-NF-κB. In conclusion, the data suggested that the PCS extract attenuated AGEs-induced renal mesangial cell proliferation and fibrosis via the suppression of oxidative stress and the downregulation of inflammatory and fibrotic factor expression.

Emodin - A natural anthraquinone derivative with diverse pharmacological activities

Emodin (1,3,8-trihydroxy-6-methyl-anthraquinone) is a natural anthraquinone derivative that is present in numerous globally renowned herbal medicines. It is recognised as a protein tyrosine kinase inhibitor and as an anticancer drug, active against various tumour cells, including lung, breast, liver, and ovarian cancer cells. Recently, its role in combination chemotherapy with various allopathic medicines, to minimize their toxicity and to enhance their efficacy, has been studied. The use of emodin in these therapies is gaining popularity, due to fewer associated side effects compared with standard anticancer drugs. Emodin has a broad therapeutic window, and in addition to its antineoplastic activity, it displays anti-ulcer, anti-inflammatory, hepatoprotective, neuroprotective, antimicrobial, muscle relaxant, immunosuppressive and antifibrotic activities, in both in vitro and in vivo models. Although reviews on the anticancer activity of emodin have been published, none coherently unite all the pharmacological properties of emodin, particularly the anti-oxidant, antimicrobial, antidiabetic, immunosuppressive and hepatoprotective activities of the compound. Hence, in this review, all of the available data regarding the pharmacological properties of emodin are explored, with particular emphasis on the modes of action of the molecule. In addition, the manuscript details the occurrence, biosynthesis and chemical synthesis of the compound, as well as its toxic effects on biotic systems.

Fibronectin-Mediated Inflammatory Signaling Through Integrin α5 in Vascular Remodeling

Background

Adhesion of vascular endothelial cells to the underlying basement membrane potently modulates endothelial cells to cells' inflammatory activation. The normal basement membrane proteins laminin and collagen IV attenuate inflammatory signaling in part through integrin α2β1. In contrast, fibronectin, the provisional matrix protein found in injured, remodeling or inflamed vessels, sensitizes endothelial cells to inflammatory stimuli through integrins α5β1and and αvβ3. A chimeric integrin in which the cytoplasmic domain of α5 is replaced with that of α2 pairs with β1 and binds fibronectin but signals like α2β1.

Methods and Results

Here, we examined mice in which integrin α5 is replaced with the α5/2 chimera, using the transverse aortic constriction and partial carotid ligation models of vessel remodeling. Following transverse aortic constriction and partial carotid ligation surgery, wild‐type mice showed increased fibronectin deposition and expression of inflammatory markers, which were strongly attenuated in a5/2 mice. α5/2 mice also showed reduced artery wall hypertrophy in the transverse aortic constriction model and diminished inward remodeling in the partial carotid ligation model. Acute atherosclerosis after partial carotid ligation in hyperlipidemic ApoE^−/− mice on a high fat diet was dramatically decreased in α5/2 mice.

Conclusions

Fibronectin and integrin α5 signaling is a key element of pathological vascular remodeling in acute models of both hypertension and disturbed flow. These results underscore the key role for integrin α5 signaling in pathological vascular remodeling associated with hypertension and atherosclerosis and support its potential as a therapeutic target.

Natural product therapies in chronic kidney diseases: An update

Chronic kidney disease is one of the major worldwide public health problems. Traditional Chinese medications have been widely used for chronic kidney disease treatment. As the development of modern phytochemistry technology, natural products have been isolated from traditional Chinese medications, which provide a more precise method for the investigation of traditional Chinese medications. In this article, we selected eight natural products from traditional Chinese medications for chronic kidney disease therapy to summarize the recent advances for the development of new medications.

Emodin alleviates high glucose-induced oxidative stress, inflammation and extracellular matrix accumulation of mesangial cells by the circ_0000064/miR-30c-5p/Lmp7 axis

Emodin has been shown to exert a renoprotective effect in diabetic nephropathy (DN). In this paper, we investigated whether circular RNAs (circRNAs) might be involved in the renoprotective mechanism of emodin in DN. The levels of malondialdehyde (MDA), reactive oxygen species (ROS), superoxide dismutase (SOD), interleukin-1β (IL-1β), IL-6 and tumor necrosis factor-α (TNF-α) were measured using the corresponding assay kits. The expression levels of circ_0000064, microRNA (miR)-30c-5p, large multifunctional protease 7 (Lmp7), fibronectin (FN), and collagen type I (Col.1) were gauged by quantitative real-time polymerase chain reaction (qRT-PCR) or western blot. Subcellular localization assay was used to assess the cellular localization of circ_0000064. Targeted relationships among circ_0000064, miR-30c-5p and Lmp7 were confirmed by dual-luciferase reporter, RNA pull-down and RNA immunoprecipitation (RIP) assays. Our data showed the alleviative effect of emodin on HG-induced oxidative stress, inflammation and extracellular matrix (ECM) accumulation in SV-MES13 cells. Circ_0000064 was an importantly downstream effector of emodin function in HG-induced SV40-MES13 cells. Moreover, circ_0000064 directly targeted miR-30c-5p, and circ_0000064 modulated Lmp7 expression through miR-30c-5p. Circ_0000064 silencing alleviated HG-induced cell oxidative stress, inflammation and ECM accumulation via up-regulating miR-30c-5p. The enforced expression of miR-30c-5p attenuated HG-induced oxidative stress, inflammation and ECM accumulation in SV40-MES13 cells by targeting Lmp7. Our findings identified that emodin alleviated HG-induced oxidative stress, inflammation and ECM accumulation in SV40-MES13 cells at least partially by the regulation of the circ_0000064/miR-30c-5p/Lmp7 axis.

Herbal antioxidants in dialysis patients: a review of potential mechanisms and medical implications

The consumption of exogenous antioxidants isolated from herbal extracts has shown beneficial effects on ameliorating dialysis-related complications through debilitating oxidative stress and inflammatory process. Many clinical studies available in public databases have reported the improved consequences of dialysis in patients supplemented with herbal antioxidants. Exploration of such data offers great possibilities for gaining insights into the potential mechanisms and medical implications of herbal antioxidants. In this work, the mechanisms and implications of some famous bioactive substances including silymarin, curcumin, resveratrol, emodin, and quercetin on the consequences of dialysis in chronic kidney disease (CKD) patients were explored. The protective features of silymarin are due to the flavonoid complex silybin. Curcumin is an active element from the root of curcuma longa with extensive beneficial properties, including antioxidant, anti-inflammatory activity, and inhibitory effects on cell apoptosis. Resveratrol can reduce the oxidative stress by neutralization of free radicals. Emodin is known as a natural anthraquinone derivative isolated from Chinese herbs. Finally, quercetin has been reported to exhibit several properties including antioxidant, anti-diabetic, analgesic, antihistaminic, antiviral, cholesterol reducer, and renal hemodynamic modulator. However, potential mechanisms and medical implications of the aforementioned herbal antioxidants seem to be more complicated, that is, more studies are required in this field.

Shenkang VII Recipe Attenuates Unilateral Ureteral Obstruction-induced Renal Fibrosis via TGF-β/Smad, NF-κB and SHH Signaling Pathway

This study aimed to explore the protective effects of the traditional Chinese Medicine formula Shenkang VII recipe (SK-7) on renal fibrosis and the mechanisms. Renal fibrosis was induced by unilateral ureteral obstruction (UUO) in rats. The rats were then divided into 5 groups: control group (Sham operation), UUO model group, UUO model plus low to high doses of SK-7 (0.5, 1.0, or 2.0 g/kg/day, for 14 days) groups. The animals were sacrificed on the 7th or 14th day. Kidney tissues were collected for histopathological examinations (hematoxylin and eosin and Masson's trichrome staining). Immunohistochemistry was used to detect the expression of collagen type III (Col III), fibronectin (FN), α-smooth muscle actin (α-SMA), TIMP metallopeptidase inhibitor 2 (TIMP2), matrix metallopeptidase 2 (MMP2), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and monocyte chemotactic protein-1 (MCP-1). The TGF-β1/Smad, NF-kB and Sonic hedgehog signaling proteins were detected by Western blotting. Our results showed that SK-7 prevented UUO-induced renal injury and accumulation of collagen fibrils. Renal fibrosis biomarkers Col III, FN, α-SMA and TIMP2 were increased in the rats after UUO and decreased by SK-7, while MMP2 was upregulated after treatment. SK-7 also suppressed the levels of TNF-α, IL-1β and MCP-1 in UUO rats. In addition, SK-7 inhibited activation of the TGF-β/Smad, NF-κB and sonic hedgehog signaling (SHH) pathways. Taken together, these findings suggest that SK-7 may regulate the synthesis and degradation of extracellular matrix, reduce inflammation and suppress the proliferation of fibroblasts, by blocking the TGF-β1/Smad, NF-κB and SHH signaling pathways to exert its anti-renal fibrosis effect in UUO rats.

A review on the efficacy and mechanism of action of Shenkang injection against chronic kidney disease

Chronic kidney disease (CKD) is one of the most common conditions which significantly increases the risk for serious health outcomes. Epidemiological investigations have shown that CKD has become a serious global health problem. At present, there are no treatments for CKD, thus the need for an effective and safe treatment for this condition. Shenkang Injection (SKI), which is an herbal medication in Chinese Medicine, has been used in the management and treatment of CKD and has achieved favorable therapeutic effects. The purpose of this paper is to review the clinical efficacy, mechanism of action, and safety profile of SKI when used in CKD, and to provide comprehensive potential evidence for its clinical application.

Parthenolide, an NF-κB inhibitor, alleviates peritoneal fibrosis by suppressing the TGF-β/Smad pathway

Transforming growth factor (TGF)-β/Smad signalling plays a central role in the pathogenesis of peritoneal fibrosis related to peritoneal dialysis (PD). Parthenolide (PTL), a naturally occurring phytochemical, is isolated from the shoots of feverfew (Tanacetum parthenium) and displays analgesia, anti-inflammation and anticancer activities. In this study, we examined the therapeutic potential of PTL on PD-related peritoneal fibrosis induced by daily intraperitoneal injection of 4.25% dextrose-containing PD fluid (PDF) in vivo and TGF-β1-induced epithelial-mesenchymal transition (EMT) in vitro. PTL was administered daily before PDF injection or after 14 days of PDF injection. Both PTL treatments showed a protective effect on peritoneal fibrosis and prevented peritoneal dysfunction. Similarly, PTL suppressed the expression of fibrotic markers (fibronectin and collagen I) and restored the expression of the epithelial marker (E-cadherin) in TGF-β1-treated HMrSV5 cells. Furthermore, PTL inhibited TGF-β1-induced Smad2 and Smad3 phosphorylation and nuclear translocation but did not influence Smad1/5/9 phosphorylation or activate other downstream signalling pathways of TGF-β1, including AKT, extracellular signal-regulated kinase (ERK) or p38. In conclusion, PTL treatment may represent an effective and novel therapy for PD-associated peritoneal fibrosis by suppressing the TGF-β/Smad pathway.

Bioactive phytochemicals that regulate the cellular processes involved in diabetic nephropathy

BACKGROUND

Owing to the multiple causative factors, the current advances in medication for diabetic nephropathy (DN) do not appear to have improved therapies for patients. Furthermore, use of multiple synthetic medications has shown various adverse effects and ultimately leads to deterioration of the condition. Medicinal plants and their bioactive constituents are considered to be safer and more effective than synthetic medicines against various chronic diseases. Therefore, the use of natural products in the management of DN has been suggested. In this article, we review medicinal plants and their specific bioactive phytochemicals that regulate the various cellular processes involved in the initiation of DN. A wide range of literature on phytochemicals and medicinal plants that may ameliorate DN was explored from the online available English works in various electronic databases, including Embase, Google Scholar, PubMed, Scopus, and Science Direct.

RESULTS

Medicinal plants possess various bioactive constituents, which may slow or ameliorate the progression of DN and improve renal function through the targeting of multiple pathological causes via different pathways, including p38MAPK, JNK, ERK, TGF-β, RhoA, NF-κB, Wnt, JAK-STAT, AMPK, mTOR, Akt, and TXNIP. Depletion or inhibition of these accelerating factors may provide a significant treatment for DN.

CONCLUSION

Based on various experimental studies, traditional herbs and their bioactive constituents regulate the cellular processes involved in the initiation of DN owing to their significant pharmacological activities; however, the efficacy in animal models and humans has not yet been explored. Therefore, studies should be performed to evaluate the nephroprotective effects of medicinal plants in preclinical animal models and in humans.

Effect of Emodin on Preventing Postoperative Intra-Abdominal Adhesion Formation

BACKGROUND

Postoperative intra-abdominal adhesions are a major complication after abdominal surgery. Although various methods have been used to prevent and treat adhesions, the effects have not been satisfactory. Emodin, a naturally occurring anthraquinone derivative and an active ingredient in traditional Chinese herbs, exhibits a variety of pharmacological effects. In our study, we demonstrated the effect of emodin treatment on preventing postoperative adhesion formation.

MATERIALS AND METHODS

A total of 48 rats were divided into six groups. Abdominal adhesions were created by abrasion of the cecum and its opposite abdominal wall. In the experimental groups, the rats were administered daily oral doses of emodin. On the seventh day after operation, the rats were euthanized, and blood and pathological specimens were collected. Abdominal adhesion formation was evaluated by necropsy, pathology, immunohistochemistry, Western blot, and enzyme-linked immunosorbent assay analyses.

RESULTS

Abdominal adhesions were markedly reduced by emodin treatment. Compared with the control group, collagen deposition was reduced and the peritoneal mesothelial completeness rate was higher in the emodin-treated groups. Emodin had anti-inflammatory effects, reduced oxidative stress, and promoted the movement of the intestinal tract (P < 0.05).

CONCLUSION

Emodin significantly reduced intra-abdominal adhesion formation in a rat model.

Dahuang Fuzi Decoction Attenuates Renal Fibrosis and Ameliorates Mitochondrial Dysfunction in Chronic Aristolochic Acid Nephropathy

Objectives. The effects of the traditional formula Dahuang Fuzi Decoction (DFD) on chronic aristolochic acid nephropathy (AAN) in mice and its underlying mechanisms were studied. Methods. Mice were randomly divided into the following six groups: the control group, the model group (AAN), the saline-treated group (AAN + vehicle), the normal dose DFD-treated group (AAN + NDFD), the high dose DFD-treated group (AAN + HDFD), and the rosiglitazone treated group (AAN + Rosi). After treating for 8 weeks, 24 h urine and blood samples were collected and the mice sacrificed to study the biochemical parameters associated with renal function. The samples were analyzed for renal fibrosis and mitochondrial dysfunction (MtD) markers. To achieve that, collagen III, collagen I, mitochondrial DNA copy numbers (mtDNA), mitochondrial membrane potential (MMP), ATP content, and ROS production were evaluated. Results. Our results showed that proteinuria, kidney function, and the renal pathological characteristics were improved by DFD and rosiglitazone. The expression of collagen III and collagen I decreased after treating with either DFD or rosiglitazone. Mitochondrial dysfunction based on the increase in ROS production, decrease in mitochondrial DNA copy numbers, and reduction of MMP and ATP content was improved by DFD and rosiglitazone. Conclusions. DFD could protect against renal impairments and ameliorate mitochondrial dysfunction in chronic AAN mice.

Tangshen Formula Attenuates Colonic Structure Remodeling in Type 2 Diabetic Rats

Aim. This study investigated the effect and mechanism of the Chinese herbal medicine Tangshen Formula (TSF) on GI structure remodeling in the rat model of diabetes. Methods. Type 2 diabetic rats were used. Wet weight per unit length, layer thicknesses, levels of collagens I and III, nuclear factor kappa B (NF-κB), interferon-γ (IFN-γ), interleukin-6 (IL-6), transforming growth factor-β1 (TGF-β1), and Smad2/3 expression in the rat colon were measured. Results. Compared with the control group animals, wet weight and layer thicknesses of the colon increased, and expressions of collagens I and III, NF-κB, IFN-γ, IL-6, TGF-β1, and Smad2/3 increased significantly in the diabetic animals. TSF inhibited increase in colonic wet weight and layer thicknesses, downregulated expressions of collagens I and III in the mucosal layer, and downregulated expressions of NF-κB, IFN-γ, IL-6, TGF-β1, and Smad2/3 in the colon wall. Furthermore, level of expression of NF-κB was associated with those of TGF-β1 and Smad2/3. Expression of TGF-β1 was associated with the most histomorphometric parameters including colonic weight, mucosal and muscle thicknesses, and levels of collagens I and III in mucosal layer. Conclusion. TSF appears to attenuate colonic structure remodeling in type 2 diabetic rats through inhibiting the overactivated pathway of NF-κB, thus reducing expressions of TGF-β1.

Roles of the NLRP3 inflammasome in the pathogenesis of diabetic nephropathy

Diabetic nephropathy (DN) is a serious complication of diabetes mellitus, and persistent inflammation in circulatory and renal tissues is an important pathophysiological basis for DN. The essence of the microinflammatory state is the innate immune response, which is central to the occurrence and development of DN. Members of the inflammasome family, including both "receptors" and "regulators", are key to the inflammatory immune response. Nucleotide binding and oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) and other inflammasome components are able to detect endogenous danger signals, resulting in activation of caspase-1 as well as interleukin (IL)-1β, IL-18 and other cytokines; these events stimulate the inflammatory cascade reaction, which is crucial for DN. Hyperglycaemia, hyperlipidaemia and hyperuricaemia can activate the NLRP3 inflammasome, which then mediates the occurrence and development of DN through the K⁺ channel model, the lysosomal damage model and the active oxygen cluster model. In this review, we survey the involvement of the NLRP3 inflammasome in various signalling pathways and highlight different aspects of their influence on DN. We also explore the important effects of the NLRP3 inflammasome on kidney function and structural changes that occur during DN development and progression. It is becoming more evident that NLRP3 inflammasome targeting has therapeutic potential for the treatment of DN.

Emodin: A Review of its Pharmacology, Toxicity and Pharmacokinetics

Emodin is a natural anthraquinone derivative that occurs in many widely used Chinese medicinal herbs, such as Rheum palmatum, Polygonum cuspidatum and Polygonum multiflorum. Emodin has been used as a traditional Chinese medicine for over 2000 years and is still present in various herbal preparations. Emerging evidence indicates that emodin possesses a wide spectrum of pharmacological properties, including anticancer, hepatoprotective, antiinflammatory, antioxidant and antimicrobial activities. However, emodin could also lead to hepatotoxicity, kidney toxicity and reproductive toxicity, particularly in high doses and with long-term use. Pharmacokinetic studies have demonstrated that emodin has poor oral bioavailability in rats because of its extensive glucuronidation. This review aims to comprehensively summarize the pharmacology, toxicity and pharmacokinetics of emodin reported to date with an emphasis on its biological properties and mechanisms of action. Copyright © 2016 John Wiley & Sons, Ltd.

Panax notoginseng saponins protect kidney from diabetes by up-regulating silent information regulator 1 and activating antioxidant proteins in rats

OBJECTIVE

To explore the mechanism of the protective effects of Panax notoginseng saponins (PNS) on kidney in diabetic rats.

METHODS

Diabetic rat model was obtained by intravenous injection of alloxan, and the rats were divided into model, PNS-100 mg/(kg day) and PNS-200 mg/(kg day) groups, 10 each. Another 10 rats injected with saline were served as control. Periodic acid-Schiff staining and immunological histological chemistry were used to observe histomorphology and tissue expression of bone morphogenetic protein-7 (BMP-7). Silent information regulator 1 (SIRT1) was silenced in rat mesangial cells by RNA interference. The mRNA expressions of SIRT-1, monocyte chemoattractant protein-1 (MCP-1), transforming growth factor β1 (TGF-β1) and plasminogen activator inhibitor-1 (PAI-1) were analyzed by reverse transcription polymerase chain reaction. The protein expressions of SIRT1 and the acetylation of nuclear factor κB (NF-κB) P65 were determined by western blotting. The concentration of MCP-1, TGF-β1 and malondialdehyde (MDA) in culture supernatant were detected by enzyme-linked immuno sorbent assay. The activity of superoxide dismutase (SOD) was detected by the classical method of nitrogen and blue four.

RESULTS

In diabetic model rats, PNS could not only reduce blood glucose and lipid (P<0.01), but also increase protein level of BMP-7 and inhibit PAI-1 expression for suppressing fibrosis of the kidney. In rat mesangial cells, PNS could up-regulate the expression of SIRT1 (P<0.01) and in turn suppress the transcription of TGF-β1 (P<0.05) and MCP-1 (P<0.05). PNS could also reverse the increased acetylation of NF-κB p65 by high glucose. In addition, redox regulation factor MDA was down-regulated (P<0.05) and SOD was up-regulated (P<0.01), which were both induced by SIRT1 up-regulation.

CONCLUSIONS

PNS could protect kidney from diabetes with the possible mechanism of up-regulating SIRT1, therefore inhibiting inflammation through decreasing the induction of inflammatory cytokines and TGF-β1, as well as activating antioxidant proteins.

G protein-coupled receptors: potential therapeutic targets for diabetic nephropathy

Diabetic nephropathy, a lethal microvascular complication of diabetes mellitus, is characterized by progressive albuminuria, excessive deposition of extracellular matrix, thickened glomerular basement membrane, podocyte abnormalities, and podocyte loss. The G protein-coupled receptors (GPCRs) have attracted considerable attention in diabetic nephropathy, but the specific effects have not been elucidated yet. Likewise, abnormal signaling pathways are closely interrelated to the pathologic process of diabetic nephropathy, despite the fact that the mechanisms have not been explored clearly. Therefore, GPCRs and its mediated signaling pathways are essential for priority research, so that preventative strategies and potential targets might be developed for diabetic nephropathy. This article will give us comprehensive overview of predominant GPCR types, roles, and correlative signaling pathways in diabetic nephropathy.

Extract of Rhizoma Polygonum cuspidatum reduces early renal podocyte injury in streptozotocin‑induced diabetic rats and its active compound emodin inhibits methylglyoxal‑mediated glycation of proteins

Podocyte injury contributes to renal damage and, eventually, to the occurrence of proteinuria in diabetic nephropathy. The aim of the present study was to investigate the effect of an ethanol extract from Rhizoma Polygonum cuspidatum (P. cuspidatum) on proteinuria and podocyte injury, and elucidate the underlying mechanism for streptozotocin (STZ)-induced diabetic nephropathy. The protective effects of P. cuspidatum extract (PCE) on renal podocytes in STZ-induced diabetic rats were also investigated. PCE (100 or 350 mg/kg/day) was administered to STZ-induced diabetic rats for 16 weeks, and blood glucose levels, body weight and proteinuria were measured. A double labeling technique with the terminal deoxynucleotidyl transferase dUTP nick end labeling assay was performed and synaptopodin expression was observed. In addition, cleaved caspase-3, methylglyoxal (MGO) and 8-hydroxydeoxyguanosine (8-OHdG) expression levels were measured. STZ-induced diabetic rats developed hyperglycemia and proteinuria. Increased apoptosis of the podocytes and increased cleaved caspase-3, MGO and 8-OHdG expression levels, as well as decreased synaptopodin expression were detected in the glomeruli of STZ-induced diabetic rats. However, treatment with PCE for 16 weeks restored protein levels to normal, and reduced podocyte loss and apoptosis. Levels of caspase-3 and MGO expression, as well as oxidative stress were ameliorated by PCE treatment. In addition, emodin, a biologically active ingredient of PCE, exerted an MGO scavenging effect and inhibited MGO-derived advanced glycation end-product formation. These findings indicate that PCE may be administered to prevent proteinuria and podocyte loss in STZ-induced diabetic rats partly by inhibiting podocyte apoptosis and cleaved caspase-3 expression, and by restoring the balance of oxidative stress and MGO expression.

Research progress in signalling pathway in diabetic nephropathy

Diabetic nephropathy, a lethal diabetic complication, is a leading cause of end-stage renal disease, which is pathologically characterized by thickened tubular basal and glomerular membranes, accumulated extracellular matrix, and progressive mesangial hypertrophy. Growing evidence indicates that diabetic nephropathy is induced by multiple conditions, such as glucose metabolism disorder, oxidative stress, numerous inflammatory factors and cytokines, and haemodynamic changes that lead to the occurrence and development of diabetic nephropathy based on genetic susceptibility. A variety of abnormalities in the signalling pathway may interact to produce these pathologic processes. Research has aimed to highlight the signalling pathway mechanisms that lead to diabetic nephropathy so that preventative strategies and effective therapies might be developed. In this review, important pathways that appear to be involved in driving these processes are discussed.

The study on the material basis and the mechanism for anti-renal interstitial fibrosis efficacy of rhubarb through integration of metabonomics and network pharmacology

The cooperative material basis of the multi-component and multi-target mechanism of action of Traditional Chinese Medicine (TCM) is difficult to elucidate because of the current lack of appropriate techniques and strategies.

Root of Polygonum cuspidatum extract reduces progression of diabetes-induced mesangial cell dysfunction via inhibition of platelet-derived growth factor-BB (PDGF-BB) and interaction with its receptor in streptozotocin-induced diabetic rats

Background

Platelet-derived growth factor–BB (PDGF-BB) is highly expressed in the renal tissues of patients with diabetic nephropathy, and it plays an important role in the initiation and progression of diabetic nephropathy. The aim of this study was to evaluate the protective effects of root of Polygonum cuspidatum extract (PCE) on early renal glomerular proliferation in streptozotocin (STZ)-induced diabetic rats.

Methods

PCE (100, 350 mg/kg/day) was administered to diabetic rats for 16 weeks. Blood glucose and albuminuria were measured. Renal histology, α-smooth muscle actin (α-SMA), and proliferating cell nuclear antigen (PCNA) expression levels were also examined.

Results

After 16 weeks of treatment with PCE, severe hyperglycemia and albuminuria were observed in the diabetic rats. The expressions levels of α-SMA and PCNA proteins were significantly increased in the glomeruli of the diabetic rats. The expression levels of PDGF-BB and its receptor expressions were greatly increased in the glomeruli of the diabetic rats. However, PCE markedly reduced albuminuria in the diabetic rats. PCE inhibited α-SMA and PCNA up-regulation and ameliorated PDGF-BB and PEGFR-ß protein expression in the diabetic rats. In addition, the binding of PDGF-BB/PDGFR-ß was inhibited by PCE as shown by an in vitro assay.

Conclusions

These results suggest that PCE has an inhibitory effect on mesangial proliferation in diabetic renal tissues via the inhibition of the interaction of PDGF-BB with its receptor. PCE may have beneficial effects in preventing the progression of diabetic nephropathy.

Electronic supplementary material

The online version of this article (doi:10.1186/1472-6882-14-477) contains supplementary material, which is available to authorized users.

Dahuang Fuzi Decoction ameliorates tubular epithelial apoptosis and renal damage via inhibiting TGF-β1-JNK signaling pathway activation in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Dahuang Fuzi Decoction (DFD) is a traditional well-prescribed formula for the treatment of chronic kidney disease (CKD) in China. This study was carried out to examine the effects of DFD in adenine-induced tubular epithelial apoptosis and renal damage, in comparison with allopurinol (AP), then to clarify the therapeutic mechanisms in vivo.

MATERIALS AND METHODS

A rat model of renal damage was created by adenine. Rats in Normal and Vehicle groups received distilled water, while rats in DFD and AP groups received DFD and AP, respectively. Proteinuria; urinary N-acetyl-β-D-glucosaminidase (NAG) levels; the blood biochemical parameters; renal histopathology damage; transferase-mediated dUTP nick-end labeling (TUNEL)-staining; the key molecular protein expressions in mitochondrial and transforming growth factor (TGF)-β1-c-JunNH2-terminal kinase (JNK) pathways were examined, respectively.

RESULTS

Adenine administration induced severe renal damages, as indicated by the mass proteinuria, the heavy urinary NAG, and the marked histopathological injury in tubules and interstitium. This was associated with the activation of TGF-β1-JNK signaling pathway and tubular epithelial apoptosis. DFD treatment, however, significantly prevented proteinuria and urinary NAG elevation, and attenuated tubular epithelial apoptosis. It suppressed the protein expressions of Bax and cleaved caspase-3, whereas it enhanced the protein expression of Bcl-2. Furthermore, it also suppressed the protein levels of TGF-β1 as well as phosphorylated-JNK (p-JNK).

CONCLUSION

DFD alleviated adenine-induced tubular epithelial apoptosis and renal damage in vivo, presumably through the suppression of TGF-β1-JNK pathway activation.

Emodin ameliorates LPS-induced acute lung injury, involving the inactivation of NF-κB in mice

Acute lung injury (ALI) and its severe manifestation of acute respiratory distress syndrome (ARDS) are well-known illnesses. Uncontrolled and self-amplified pulmonary inflammation lies at the center of the pathology of this disease. Emodin, the bio-active coxund of herb Radix rhizoma Rhei, shows potent anti-inflammatory properties through inactivation of nuclear factor-κB (NF-κB). The aim of this study was to evaluate the effect of emodin on lipopolysaccharide (LPS)-induced ALI in mice, and its potential bio-mechanism. In our study, BALB/c mice were stimulated with LPS to induce ALI. After 72 h of LPS stimulation, pulmonary pathological changes, lung injury scores, pulmonary edema, myeloperoxidase (MPO) activity, total cells, neutrophils, macrophages, TNF-α, IL-6 and IL-1β in bronchoalveolar lavage fluid (BALF), and MCP-1 and E-selectin expression were notably attenuated by emodin in mice. Meanwhile, our data also revealed that emodin significantly inhibited the LPS-enhanced the phosphorylation of NF-κB p65 and NF-κB p65 DNA binding activity in lung. Our data indicates that emodin potently inhibits LPS-induced pulmonary inflammation, pulmonary edema and MCP-1 and E-selectin expression, and that these effects were very likely mediated by inactivation of NF-κB in mice. These results suggest a therapeutic potential of emodin as an anti-inflammatory agent for ALI/ARDS treatment.

Oxidative stress mediates the conversion of endothelial cells into myofibroblasts via a TGF-β1 and TGF-β2-dependent pathway

During the pathogenesis of systemic inflammation, reactive oxygen species (ROS) circulate in the bloodstream and interact with endothelial cells (ECs), increasing intracellular oxidative stress. Although endothelial dysfunction is crucial in the pathogenesis of systemic inflammation, little is known about the effects of oxidative stress on endothelial dysfunction. Oxidative stress induces several functions, including cellular transformation. A singular process of cell conversion is tendothelial-to-mesenchymal transition, in which ECs become myofibroblasts, thus losing their endothelial properties and gaining fibrotic behavior. However, the participation of oxidative stress as an inductor of conversion of ECs into myofibroblasts is not known. Thus, we studied the role played by oxidative stress in this conversion and investigated the underlying mechanism. Our results show that oxidative stress induces conversion of ECs into myofibroblasts through decreasing the levels of endothelial markers and increasing those of fibrotic and ECM proteins. The underlying mechanism depends on the ALK5/Smad3/NF-κB pathway. Oxidative stress induces the expression and secretion of TGF-β1 and TGF-β2 and p38 MAPK phosphorylation. Downregulation of TGF-β1 and TGF-β2 by siRNA technology abolished the H2O2-induced conversion. To our knowledge, this is the first report showing that oxidative stress is able to induce conversion of ECs into myofibroblasts via TGF-β secretion, emerging as a source for oxidative stress-based vascular dysfunction. Thus, oxidative stress emerges as a decisive factor in inducing conversion of ECs into myofibroblasts through a TGF-β-dependent mechanism, changing the ECs protein expression profile, and converting normal ECs into pathological ones. This information will be useful in designing new and improved therapeutic strategies against oxidative stress-mediated systemic inflammatory diseases.

Effects of high glucose on integrin activity and fibronectin matrix assembly by mesangial cells

Aberrant accumulation of collagen IV defines diabetic nephropathy. It is shown here that high glucose increases fibronectin matrix assembly by activating integrin receptors on kidney cells. Collagen IV accumulation depends on this fibronectin matrix. Targeting fibronectin matrix may be a useful therapy to stem matrix accumulation in the diabetic kidney.

The filtration unit of the kidney is the glomerulus, a capillary network supported by mesangial cells and extracellular matrix (ECM). Glomerular function is compromised in diabetic nephropathy (DN) by uncontrolled buildup of ECM, especially type IV collagen, which progressively occludes the capillaries. Increased levels of the ECM protein fibronectin (FN) are also present; however, its role in DN is unknown. Mesangial cells cultured under high glucose conditions provide a model system for studying the effect of elevated glucose on deposition of FN and collagen IV. Imaging of mesangial cell cultures and analysis of detergent-insoluble matrix show that, under high glucose conditions, mesangial cells assembled significantly more FN matrix, independent of FN protein levels. High glucose conditions induced protein kinase C–dependent β1 integrin activation, and FN assembly in normal glucose was increased by stimulation of integrin activity with Mn²⁺. Collagen IV incorporation into the matrix was also increased under high glucose conditions and colocalized with FN fibrils. An inhibitor of FN matrix assembly prevented collagen IV deposition, demonstrating dependence of collagen IV on FN matrix. We conclude that high glucose induces FN assembly, which contributes to collagen IV accumulation. Enhanced assembly of FN might facilitate dysregulated ECM accumulation in DN.