Isoliquiritigenin entails blockade of TGF-beta1-SMAD signaling for retarding high glucose-induced mesangial matrix accumulation

Protective Effect of Black Rice Cyanidin-3-Glucoside on Testicular Damage in STZ-Induced Type 1 Diabetic Rats

Diabetic testicular damage is quite a common and significant complication in diabetic men, which could result in infertility. The natural fertility rate of type 1 diabetes men is only 50% because of testicular damage. This research first aimed to explore the intervention effect of C3G on testicular tissue damage induced by diabetes. Here, a streptozotocin-induced type 1 diabetic rat model was established, and then C3G was administered. After 8 weeks of C3G supplementation, the symptoms of diabetes (e.g., high blood glucose, lower body weight, polydipsia, polyphagia) were relieved, and at the same time that sperm motility and viability increased, sperm abnormality decreased in C3G-treated diabetic rats. Furthermore, the pathological structure of testis was restored; the fibrosis of the testicular interstitial tissue was inhibited; and the LH, FSH, and testosterone levels were all increased in the C3G-treated groups. Testicular oxidative stress was relieved; serum and testicular inflammatory cytokines levels were significantly decreased in C3G-treated groups; levels of Bax, Caspase-3, TGF-β1 and Smad2/3 protein in testis decreased; and the level of Bcl-2 was up-regulated in the C3G-treated groups. A possible mechanism might be that C3G improved antioxidant capacity, relieved oxidative stress, increased anti-inflammatory cytokine expression, and inhibited the apoptosis of spermatogenic cells and testicular fibrosis, thus promoting the production of testosterone and repair of testicular function. In conclusion, this study is the first to reveal that testicular damage could be mitigated by C3G in type 1 diabetic rats. Our results provide a theoretical basis for the application of C3G in male reproductive injury caused by diabetes.

Isoliquiritigenin, a potential therapeutic agent for treatment of inflammation-associated diseases

ETHNOPHARMACOLOGICAL RELEVANCE

Licorice is a medicinal herb with a 2000-year history of applications in traditional Chinese medicine. Isoliquiritigenin (ISL) is a bioactive chalcone compound isolated from licorice. It has attracted increasing attention in recent years due to its excellent anti-inflammatory activity.

AIM OF THE STUDY

This study is to provide a comprehensive summary of the anti-inflammatory activity of ISL and the underlying molecular mechanisms, and discuss new insights for its potential clinical applications as an anti-inflammation agent.

MATERIALS AND METHODS

We examined literatures published in the past twenty years from PubMed, Research Gate, Web of Science, Google Scholar, and SciFinder, with single or combined key words of "isoliquiritigenin", "inflammation", and "anti-inflammatory".

RESULTS

ISL elicits its anti-inflammatory activity by mediating various cellular processes. It inhibits the upstream of the nuclear factor kappa B (NF-κB) pathway and activates the nuclear factor erythroid related factor 2 (Nrf2) pathway. In addition, it suppresses the NOD-like receptor protein 3 (NLRP3) pathway and restrains the mitogen-activated protein kinase (MAPK) pathway.

CONCLUSIONS

Current studies indicate a great therapeutical potential of ISL as a drug candidate for treatment of inflammation-associated diseases. However, the pharmacokinetics, biosafety, and bioavailability of ISL remain to be further investigated.

Natural products in traditional Chinese medicine: molecular mechanisms and therapeutic targets of renal fibrosis and state-of-the-art drug delivery systems

Renal fibrosis (RF) is the end stage of several chronic kidney diseases. Its series of changes include excessive accumulation of extracellular matrix, epithelial-mesenchymal transition (EMT) of renal tubular cells, fibroblast activation, immune cell infiltration, and renal cell apoptosis. RF can eventually lead to renal dysfunction or even renal failure. A large body of evidence suggests that natural products in traditional Chinese medicine (TCM) have great potential for treating RF. In this article, we first describe the recent advances in RF treatment by several natural products and clarify their mechanisms of action. They can ameliorate the RF disease phenotype, which includes apoptosis, endoplasmic reticulum stress, and EMT, by affecting relevant signaling pathways and molecular targets, thereby delaying or reversing fibrosis. We also present the roles of nanodrug delivery systems, which have been explored to address the drawback of low oral bioavailability of natural products. This may provide new ideas for using natural products for RF treatment. Finally, we provide new insights into the clinical prospects of herbal natural products.

Isoliquiritigenin attenuates high glucose-induced proliferation, inflammation, and extracellular matrix deposition in glomerular mesangial cells by suppressing JAK2/STAT3 pathway

To investigate the effect of isoliquiritigenin (ISL) on high glucose (HG)-induced glomerular mesangial cells (GMCs) proliferation, extracellular matrix (ECM) deposition and inflammation, and the underlying mechanisms. Mouse GMCs (SV40-MES-13) were cultured in HG medium, with or without ISL. The proliferation of GMCs was determined by MTT assay. The production of proinflammatory cytokines was detected by qRT-PCR and ELISA. The expression of connective tissue growth factor (CTGF), TGF-β1, collagen IV, and fibronectin was measured by qRT-PCR and western blot. The phosphorylation of JAK2 and STAT3 was examined by western blot. Next, JAK2 inhibitor AG490 was applied to HG-exposed GMCs. The levels of JAK2/STAT3 phosphorylation and pro-fibrotic markers were analyzed by western blot, and the secretion of TNF-α and IL-1β was evaluated by ELISA. GMCs were treated with HG, HG plus ISL or HG plus ISL, and recombinant IL-6 (rIL-6) which is a JAK2 activator. The levels of JAK2/STAT3 activation, ECM formation, and proinflammatory cytokines secretion were determined by western blot and ELISA, respectively. In mouse GMCs, ISL successfully repressed HG-induced hyperproliferation; production of TNF-α and IL-1β; expression of CTGF, TGF-β1, collagen IV, and fibronectin; and activation of JAK2/STAT3. Similar to ISL, AG490 was able to reverse the inflammation and ECM generation caused by HG. Moreover, rIL-6 impeded the amelioration of ISL on HG-induced adverse effects. Our study demonstrated that ISL displayed preventive effects on HG-exposed GMCs through inhibiting JAK2/STAT3 pathway and provided an insight into the application of ISL for diabetic nephropathy (DN) treatment.

Chromium Picolinate Protects against Testicular Damage in STZ-Induced Diabetic Rats via Anti-Inflammation, Anti-Oxidation, Inhibiting Apoptosis, and Regulating the TGF-β1/Smad Pathway

Chromium picolinate (CP) is an organic compound that has long been used to treat diabetes. Our previous studies found CP could relieve diabetic nephropathy. Thus, we speculate that it might have a positive effect on diabetic testicular injury. In this study, a diabetic rat model was established, and then the rats were treated with CP for 8 weeks. We found that the levels of blood glucose, food, and water intake were reduced, and body weight was enhanced in diabetic rats after CP supplementation. Meanwhile, in CP treatment groups, the levels of male hormone and sperm parameters were improved, the pathological structure of the testicular tissue was repaired, and testicular fibrosis was inhibited. In addition, CP reduced the levels of serum inflammatory cytokines, and decreased oxidative stress and apoptosis in the testicular tissue. In conclusion, CP could ameliorate testicular damage in diabetic rats, as well as being a potential testicle-protective nutrient in the future to prevent the testicular damage caused by diabetes.

Pharmacokinetics and tissue distribution of 12 major active components in normal and chronic gastritis rats after oral administration of Weikangling capsules

ETHNOPHARMACOLOGICAL RELEVANCE

Weikangling Capsules (WKLCs) have been used in the clinic for the treatment of gastrointestinal disorders for more than 30 years. However, the pharmacokinetic characteristics and tissue distribution of its major bioactive components in rats under different physiological and pathological conditions are unclear.

AIM OF THE STUDY

In this study, we aimed to clarify the differences in pharmacokinetic parameters and tissue distribution of the major active components in WKLCs under physiological and pathological states.

MATERIALS AND METHOD

Normal and ethanol-induced chronic gastritis rats received 2.16 g/kg WKLCs by gavage, and urine, feces, plasma, and tissue (heart, liver, spleen, lung, kidney, stomach, and small intestine) samples were obtained. The active components in urine, feces and plasma were detected by ultra-high-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UHPLC-Q-TOF-MS/MS). A rapid and sensitive analytical method, ultra-high-performance liquid chromatography coupled with triple-quadrupole linear ion-trap tandem mass spectrometry (UHPLC-QTRAP-MS/MS), was established and validated to clarify and compare the pharmacokinetics and tissue distribution of the major active components in normal and chronic gastritis rats.

RESULTS

A total of 36 chemical components in the feces, urine, and plasma of chronic gastritis rats were identified by UHPLC-Q-TOF-MS/MS. Among them, 20 were the prototype components of WKLCs, and 16 were metabolites. The pharmacokinetic characteristics and tissue distribution of 12 prototype components were successfully analyzed by UHPLC-QTRAP-MS/MS. The pharmacokinetic results showed that the C_max, AUC_0-t, and AUC_0-∞ of paeoniflorin, glycyrrhizic acid, and glycyrrhetinic acid were distinctly higher than those of the other components in normal and chronic gastritis rats. Compared to normal rats, the C_max, AUC_0-t, and AUC_0-∞ of albiflorin, liquiritin apioside, liquiritin, isoliquiritin, ononin, isoliquiritigenin, dactylorhin A, and glycyrrhizic acid were significantly increased in chronic gastritis rats (P < 0.05), while the C_max, AUC_0-t and AUC_0-∞ of militarine and liquiritigenin had significantly lower decreases in chronic gastritis rats (P < 0.05). The results of the tissue distribution showed that the 12 components were widely distributed in the heart, liver, spleen, lung, kidney, stomach, and small intestine of rats, of which the liver, kidney, stomach, and small intestine were the main accumulative organs. Compared with normal rats, the concentrations of 12 components in the liver, kidney, stomach, and small intestine of chronic gastritis rats were widely higher than those of normal rats at the same time points.

CONCLUSION

The pharmacokinetic characteristics and tissue distribution of 12 active components of WKLCs were comprehensively characterized and elucidated in normal and chronic gastritis rats. These findings laid a solid foundation for revealing the pharmacodynamic material basis of WKLCs in treating gastrointestinal disorders.

A Cyclopentanone Compound Attenuates the Over-Accumulation of Extracellular Matrix and Fibrosis in Diabetic Nephropathy via Downregulating the TGF-β/p38MAPK Axis

Excessive accumulation of the extracellular matrix (ECM) is a crucial pathological process in chronic kidney diseases, such as diabetic nephropathy, etc. The underlying mechanisms of how to decrease ECM deposition to improve diabetic nephropathy remain elusive. The present study investigated whether cyclopentanone compound H8 alleviated ECM over-deposition and fibrosis to prevent and treat diabetic nephropathy. HK-2 cell viability after treatment with H8 was measured by an MTT assay. ECM alterations and renal fibrosis were identified in vitro and in vivo. A pharmacological antagonist was used to detect associations between H8 and the p38 mitogen-activated protein kinase (p38MAPK) signaling pathway. H8 binding was identified through computer simulation methods. Studies conducted on high glucose and transforming growth factor β1 (TGF-β1)-stimulated HK-2 cells revealed that the p38MAPK inhibitor SB 202190 and H8 had similar pharmacological effects. In addition, excessive ECM accumulation and fibrosis in diabetic nephropathy were remarkably improved after H8 administration in vivo and in vitro. Finally, the two molecular docking models further proved that H8 is a specific p38MAPK inhibitor that forms a hydrogen bond with the LYS-53 residue of p38MAPK. The cyclopentanone compound H8 alleviated the over-deposition of ECM and the development of fibrosis in diabetic nephropathy by suppressing the TGF-β/p38MAPK axis.

Therapeutic Intervention in Cancer by Isoliquiritigenin from Licorice: A Natural Antioxidant and Redox Regulator

Oxidative stress could lead to a variety of body dysfunctions, including neurodegeneration and cancer, which are closely associated with intracellular signal transducers such as reactive oxygen species (ROS). It has been suggested that ROS is the upstream regulator of autophagy, and that it provides a negative feedback regulation to remove oxidative damage. Defects in the ROS-autophagic redox homeostasis could lead to the increased production of ROS and the accumulation of damaged organelles that in turn promote metabolic reprogramming and induce tumorigenesis. One significant characteristic of pancreatic cancer is the reprogramming of cellular energy metabolism, which facilitates the rapid growth, invasiveness, and the survival of cancer cells. Thus, the rectification of metabolic dysfunction is essential in therapeutic cancer targeting. Isoliquiritigenin (ISL) is a chalcone obtained from the plant Glycyrrhiza glabra, which is a powdered root licorice that has been consumed for centuries in different regions of the world. ISL is known to be a natural antioxidant that possesses diversified functions, including redox regulation in cells. This review contains discussions on the herbal source, biological properties, and anticancer potential of ISL. This is the first time that the anticancer activities of ISL in pancreatic cancer has been elucidated, with a coverage of the involvement of antioxidation, metabolic redox regulation, and autophagy in pancreatic cancer development. Furthermore, some remarks on related compounds of the isoflavonoid biosynthetic pathway of ISL will also be discussed.

Pharmacological Effects and Underlying Mechanisms of Licorice-Derived Flavonoids

Glycyrrhizae Radix et Rhizoma is the most frequently prescribed natural medicine in China and has been used for more than 2,000 years. The flavonoids of licorice have garnered considerable attention in recent decades due to their structural diversity and myriad pharmacological effects, especially as novel therapeutic agents against inflammation and cancer. Although many articles have been published to summarize different pharmacological activities of licorice in recent years, the systematic summary for flavonoid components is not comprehensive. Therefore, in this review, we summarized the pharmacological and mechanistic data from recent researches on licorice flavonoids and their bioactive components.

Network Pharmacology and Experimental Assessment to Explore the Pharmacological Mechanism of Qimai Feiluoping Decoction Against Pulmonary Fibrosis

Pulmonary fibrosis (PF) is one of the pathologic changes in COVID-19 patients in convalescence, and it is also a potential long-term sequela in severe COVID-19 patients. Qimai Feiluoping decoction (QM) is a traditional Chinese medicine formula recommended in the Chinese national medical program for COVID-19 convalescent patients, and PF is one of its indications. Through clinical observation, QM was found to improve the clinical symptoms and pulmonary function and reduce the degree of PF of COVID-19 convalescent patients. To further explore the pharmacological mechanisms and possible active components of QM in anti-PF effect, UHPLC/Q-TOF-MS was used to analyze the composition of the QM extract and the active components that can be absorbed into the blood, leading to the identification of 56 chemical compounds and 10 active components. Then, network pharmacology was used to predict the potential mechanisms and targets of QM; it predicted that QM exerts its anti-PF effects via the regulation of the epithelial-mesenchymal transition (EMT), extracellular matrix (ECM) degradation, and TGF-β signaling pathway. Finally, TGF-β1-induced A549 cells were used to verify and explore the pharmacological effects of QM and found that QM could inhibit the proliferation of TGF-β1-induced A549 cells, attenuate EMT, and promote ECM degradation by inhibiting the TGF-β/Smad3 pathway.

Integrin β3 Induction Promotes Tubular Cell Senescence and Kidney Fibrosis

Tubular cell senescence is a common biologic process and contributes to the progression of chronic kidney disease (CKD); however, the molecular mechanisms regulating tubular cell senescence are poorly understood. Here, we report that integrin β3 (ITGB3) expression was increased in tubular cells and positively correlated with fibrosis degree in CKD patients. ITGB3 overexpression could induce p53 pathway activation and the secretion of TGF-β, which, in turn, resulted in senescent and profibrotic phenotype change in cultured tubular cells. Moreover, according to the CMAP database, we identified isoliquiritigenin (ISL) as an agent to inhibit ITGB3. ISL treatment could suppress Itgb3 expression, attenuate cellular senescence, and prevent renal fibrosis in mice. These results reveal a crucial role for integrin signaling in cellular senescence, potentially identifying a new therapeutic direction for kidney fibrosis.

Chemical Profile Assessment and Potential Bioactive Component Screening of a Chinese Patent Herbal Drug Yi-Shen-Hua-Shi Granule

Yi-Shen-Hua-Shi (YSHS) Granule is a well-known patented herbal drug for treating chronic glomerulonephritis (CGN) in China. Its chemical compositions and anti-CGN components are not fully understood. This study aimed to establish the chemical profile and to identify the anti-CGN components of YSHS Granule. For these purposes, a HPLC-Q-TOF-MS/MS method was developed. A total of 105 peaks were detected in the mass spectrum of the Granule. Of these, 99 compounds were tentatively identified as terpenoids, flavonoids, coumarins, alkaloids, phenols, and other types of compounds, and 15 were further identified with reference substances. To screen bioactive compounds, a cell membrane immobilized chromatography (CMIC) method was used. Lipopolysaccharide (LPS)-challenged rat glomerular mesangial cells (HBZY-1) were incubated with YSHS Granule (100 μg/mL), and the binding components to the cell membrane were extracted and analyzed using the established HPLC-Q-TOF-MS/MS method. Seven potential bioactive components that bound to HBZY-1 cell membranes were detected and identified as calycosin-7- O-β-D-glucoside, 6-gingerol, naringin, ginsenoside Re, poncirin, liquiritigenin, and isoliquiritigenin. The outcomes of the present study provide a chemical basis for clinical use of the Granule in managing CGN, and provide quality control markers for the Granule’s production and use.

Administration of isoliquiritigenin prevents nonalcoholic fatty liver disease through a novel IQGAP2-CREB-SIRT1 axis

Isoliquiritigenin (ISO) is a flavonoid extracted from the root of licorice, which serves various biological and pharmacological functions including antiinflammatory, antioxidation, liver protection, and heart protection. However, the mechanism of its action remains elusive and the direct target proteins of ISO have not been identified so far. Through cell-based screening, we identified ISO as a potent lipid-lowering compound. ISO treatment successfully ameliorated fatty acid-induced cellular lipid accumulation and improved nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) by increasing PPARα-dependent lipid oxidation and decreasing SREBPs-dependent lipid synthesis. Both these signaling required the activation of SIRT1. Knockdown of SIRT1 resulted in the reversal of ISO beneficiary effects suggesting that the lipid-lowering activity of ISO was regulated by SIRT1 expression. To identify the direct target of ISO, limited proteolysis combined with mass spectrometry (LiP-SMap) strategy was applied and IQGAP2 was identified as the direct target for ISO in regulating lipid homeostasis. In the presence of ISO, both mRNA and protein levels of SIRT1 were increased; however, this effect was abolished by blocking IQGAP2 expression using siRNA. To explore how IQGAP2 regulated the expression level of SIRT1, proteome profiler human phospho-kinase array kit was used to reveal possible phosphorylated kinases and signaling nodes that ISO affected. We found that through phosphorylation of CREB, ISO transduced signals from IQGAP2 to upregulate SIRT1 expression. Thus, we not only demonstrated the molecular basis of ISO in regulating lipid metabolism but also exhibited for the first time a novel IQGAP2-CREB-SIRT1 axis in treating NAFLD/NASH.

Isoliquiritigenin Reverses Epithelial-Mesenchymal Transition Through Modulation of the TGF-β/Smad Signaling Pathway in Endometrial Cancer

Simple Summary

The high recurrence risk and poor prognosis of metastatic endometrial cancer are the main focus of interventional therapy. In view of this, we established in vitro and in vivo metastasis models and explored the underlying mechanisms of the epithelial-mesenchymal transition (EMT) process, cell migration ability, and metastasis in response to isoliquiritigenin (ISL). The presented in vitro and in vivo preclinical studies both demonstrated that ISL efficiently suppressed endometrial cancer cell migration and reduced the HEC-1A-LUC tumor metastasis in nude mice through inhibiting TGF-β/Smad signaling pathway. These findings shed the light for further research to highlight the ISL potential in endometrial cancer metastasis.

Abstract

Endometrial cancer is a common gynecological cancer with a poor prognosis, mostly attributed to tumor metastasis. Epithelial–mesenchymal transition (EMT) can be mediated via transforming growth factor beta (TGF-β) signaling pathway, facilitating the ability of cancer cell invasion and migration. Isoliquiritigenin (ISL) is a flavonoid derived from licorice with reported antineoplastic activities. This study aims to investigate the anti-metastatic potential of ISL on endometrial cancer both in vitro and in vivo. First, human endometrial cancer cell lines (HEC-1A, Ishikawa, and RL95-2) were treated with ISL and then subjected to functional assays such as migration assay as well as molecular analyses including immunoblotting, immunofluorescence and RT-qPCR. In addition, HEC-1A-LUC cells were implanted into female nude mice and treated with ISL by intraperitoneal injection for four weeks. Results showed that ISL inhibited cell migration and reversed the effect of TGF-β on the expression of E-cadherin, N-cadherin, vimentin, α-SMA, p-Smad3, and TWIST1/2 In vitro. Interestingly, In vivo study revealed that ISL reduced peritoneal dissemination and serum level of TGF-β1, as well as decreased the expression levels of N-cadherin, p-Smad2/3, TWIST1/2, while increased E-cadherin. Overall, ISL reverses the EMT through targeting the TGF-β/Smad signaling pathway and features a potential therapeutic treatment for metastatic endometrial cancer.

Signaling pathways and proteins targeted by antidiabetic chalcones

Chalcones have shown a broad spectrum of biological activities with clinical potential against various diseases. The biological activities are mainly attributed to the presence of α, β-unsaturated carbonyl system, perceived as potential Michael acceptors. In this review, we discussed the antioxidant potential of chalcones and elucidated the mechanisms of pathways and proteins such as carbohydrate digestive enzymes (α-amylase and α-glucosidase), aldose reductase, SGLT-2, and Nrf2 that are targeted by antidiabetic chalcones. In addition to their insulin mimetic potential, we explore the major molecular targets of chalcones and discuss the biochemical and therapeutic implication of modulating these targets. Finally, we dwell on the opulence of the literature and envisage how RNA interference-mediated gene silencing technique and in silico molecular docking could be exploited in the search for novel and more efficacious antidiabetic chalcones.

The anti-diabetic activity of licorice, a widely used Chinese herb

ETHNOPHARMACOLOGICAL RELEVANCE

A great deal of valuable experience has been accumulated in the traditional Chinese medicine (TCM) system for the treatment of "Xiaoke" disease which is known as diabetes mellitus now. As the most-commonly used Chinese herb, licorice has been used in TCM for more than two thousand years. It is often used in combination with other herbs to treat metabolic disorders, especially diabetes mellitus.

AIM OF THE STUDY

To summarize the characteristics, mechanisms, and clinical use of licorice and its active components for treating diabetes mellitus.

METHODS

PubMed, Web of Science, Research Gate, Science Direct, Google Scholar, and Academic Journals were used as information sources by the inclusion of the search terms 'diabetes', 'licorice', 'licorice extracts', 'flavonoids', 'triterpenoids', and their combinations, mainly from 2005 to 2019.

RESULTS

Licorice extracts, five flavonoids and three triterpenoids isolated from licorice possess great antidiabetic activities in vivo and in vitro. This was done by several mechanisms such as increasing the appetency and sensitivity of insulin receptor site to insulin, enhancing the use of glucose in different tissues and organs, clearing away the free radicals and resist peroxidation, correcting the metabolic disorder of lipid and protein, and improving microcirculation in the body. Multiple signaling pathways, including the PI3K/Akt, AMPK, AGE-RAGE, MAPK, NF-кB, and NLRP3 signaling pathways, are targets of the licorice compounds.

CONCLUSION

Licorice and its metabolites have a great therapeutic potential for the treatment of diabetes mellitus. However, a better understanding of their pharmacological mechanisms is needed for evaluating its efficacy and safety.

Isoliquiritigenin attenuates diabetic cardiomyopathy via inhibition of hyperglycemia-induced inflammatory response and oxidative stress

BACKGROUND

Inflammation and oxidative stress play essential roles in the occurrence and progression of diabetic cardiomyopathy (DCM). Isoliquiritigenin (ISL), a natural chalcone, exhibits strong anti-inflammatory and antioxidant activities.

HYPOTHESIS/PURPOSE

In this study, we aimed to investigate the protective effects of ISL on DCM using high glucose (HG)-challenged cultured cardiomyocytes and streptozotocin (STZ)-induced diabetic mice.

STUDY DESIGN AND METHODS

Embryonic rat heart-derived H9c2 cells challenged with a high concentration of glucose were used to evaluate the anti-inflammatory and antioxidant effects of ISL. STZ-induced diabetic mice were used to study the effects of ISL in DCM in vivo. Furthermore, cardiac fibrosis, hypertrophy, and apoptosis were explored both in vitro and in vivo.

RESULTS

ISL effectively inhibited HG-induced hypertrophy, fibrosis, and apoptosis probably by alleviating the inflammatory response and oxidative stress in H9c2 cells. Results from in vivo experiments showed that ISL exhibited anti-inflammatory and antioxidant stress activities that were characterized by the attenuation of cardiac hypertrophy, fibrosis, and apoptosis, which resulted in the maintenance of cardiac function. The protective effects of ISL against inflammation and oxidative stress were mediated by the inhibition of mitogen-activated protein kinases (MAPKs) and induction of nuclear factor-erythroid 2 related factor 2 (Nrf2) signaling pathway, respectively.

CONCLUSION

Our results provided compelling evidence that ISL, by virtue of neutralizing excessive inflammatory response and oxidative stress, could be a promising agent in the treatment of DCM. Targeting the MAPKs and Nrf2 signaling pathway might be an effective therapeutic strategy for the prevention and treatment of DCM.

Isoliquiritigenin inhibits TGF-β1-induced fibrogenesis through activating autophagy via PI3K/AKT/mTOR pathway in MRC-5 cells

Isoliquiritigenin (ISL), a natural flavonoid derived from the root of liquorice, has been reported to possess anti-inflammatory and antioxidant activities. Previous studies have found that ISL plays a crucial role in anti-fibrosis of adipose tissue and renal tissue; however, its effect on pulmonary fibrogenesis has not been demonstrated. In this study, we aimed to explore the roles and the underlying mechanisms of ISL in TGF-β1-induced fibrogenesis using human lung fibroblast-derived MRC-5 cells. Cell proliferation and migration were determined by MTT and wound healing assay, respectively. The expression levels of alpha-smooth muscle actin (α-SMA), collagen type I alpha 1 (COLIA1) and fibronectin (FN), microtubule-associated protein light chain 3 (LC3) and related signaling molecules were detected by quantitative real-time PCR, western blot and immunofluorescence assay, correspondingly. EGFP-LC3 transfection was used for autophagy analysis. The results showed that ISL inhibited the TGF-β1-induced proliferation and migration, and down-regulated the expressions of α-SMA, COLIA1 and FN. ISL treatment led to up-regulation of LC3 in TGF-β1-treated MRC-5 cells, accompanied by significant decrease in the phosphorylation levels of phosphatidylinositol 3-kinase (PI3K), protein kinase B (AKT), and mammalian target of rapamycin (mTOR). In addition, the inhibitory effects of ISL on TGF-β1-induced fibrogenic features in MRC-5 cells were enhanced by pretreatment with autophagy activator Rapmycin and PI3K/AKT inhibitor LY294002 and reversed by autophagy inhibitor 3-methyladenine and PI3K/AKT activator IGF-1. Taken together, our results demonstrated that ISL could attenuate the fibrogenesis of TGF-β1-treated MRC-5 cells by activating autophagy via suppressing the PI3K/AKT/mTOR pathway. Therefore, ISL holds a great potential to be developed as a novel therapeutic agent for the treatment of pulmonary fibrosis.

The Evolving Role of Natural Compounds in the Medical Treatment of Uterine Fibroids

Uterine fibroids (UFs) remain a significant health issue for many women, with a disproportionate impact on women of color, likely due to both genetic and environmental factors. The prevalence of UFs is estimated to be approximately 70% depending on population. UF-derived clinical symptoms include pelvic pain, excessive uterine bleeding, gastrointestinal and voiding problems, as well as impaired fertility. Nowadays numerous methods of UF treatment are available-from conservative treatment to invasive surgeries. Selecting an appropriate treatment option should be individualized and adjusted to the patient's expectations as much as possible. So far, the mainstay of treatment is surgery, but their negative impact of future fertility is clear. On the other hand, emerging new pharmaceutical options have significant adverse effects like liver function impairment, hot flashes, bone density loss, endometrial changes, and inability to attempt conception during treatment. Several natural compounds are found to help treat UFs and relieve their symptoms. In this review we summarize all the current available data about natural compounds that may be beneficial for patients with UFs, especially those who want to preserve their future fertility or have treatment while actively pursuing conception. Vitamin D, epigallocatechin gallate, berberine, curcumin, and others are being used as alternative UF treatments. Moreover, we propose the concept of using combined therapies of natural compounds on their own or combined with hormonal agents to manage UFs. There is a strong need for more human clinical trials involving these compounds before promoting widespread usage.

Natural Chalcones in Chinese Materia Medica: Licorice

Licorice is an important Chinese materia medica frequently used in clinical practice, which contains more than 20 triterpenoids and 300 flavonoids. Chalcone, one of the major classes of flavonoid, has a variety of biological activities and is widely distributed in nature. To date, about 42 chalcones have been isolated and identified from licorice. These chalcones play a pivotal role when licorice exerts its pharmacological effects. According to the research reports, these compounds have a wide range of biological activities, containing anticancer, anti-inflammatory, antimicrobial, antioxidative, antiviral, antidiabetic, antidepressive, hepatoprotective activities, and so on. This review aims to summarize structures and biological activities of chalcones from licorice. We hope that this work can provide a theoretical basis for the further studies of chalcones from licorice.

Isoliquiritigenin Suppressed Esophageal Squamous Carcinoma Growth by Blocking EGFR Activation and Inducing Cell Cycle Arrest

Isoliquiritigenin (ILQ) is a natural product isolated from licorice root which has served as traditional Chinese medicine for a long time. Recently, the antitumor effects of ILQ have been widely studied in various cancers, but the role and related mechanisms of ILQ in esophageal squamous carcinoma cells (ESCC) are still poorly understood. In our studies, ILQ showed profound antitumor activities in ESCC cells. In vitro, ILQ substantially inhibited cell proliferation and anchorage-independent growth in a panel of human ESCC cells. Mechanism studies showed that EGFR signaling pathway played an important role for ILQ to exert its antitumor activity in ESCC. Exposure to isoliquiritigenin substantially decreased EGF-induced EGFR activation and its downstream Akt and ERK1/2 signaling pathway. EGFR knockdown with shRNA in ESCC cell significantly reduced the sensitivity of cancer cells to ILQ. Moreover, it was found that ILQ had a significantly inhibitory effect on AP-1 family, the protein of Jun and Fos subfamilies was substantially downregulated, and the transcriptional activity of AP-1 family was dramatically suppressed by ILQ. By reducing the expression of cyclin D1, ESCC cells were induced G0/G1 arrest, and cell division was substantially blocked. Finally, the antitumor potency of ILQ was validated in xenograft models and the tumor growth was prominently restrained by ILQ. Briefly, our study showed that ILQ, or its analogue, appeared to be a promising new therapeutic agent for ESCC management.

Lipid-Lowering Effects of Medium-Chain Triglyceride-Enriched Coconut Oil in Combination with Licorice Extracts in Experimental Hyperlipidemic Mice

Coconut oil has gained in popularity over recent years as a healthy oil due to its potential cardiovascular benefits. Coconut oil contains medium chain triglycerides (MCT) including lauric acid and capric acid that display beneficial properties in human health. Licorice ( Glycyrrhiza uralensis) is used as a sweetener and in traditional Chinese medicine with anti-inflammatory, antimicrobial, and antioxidant activities. This study investigated the in vivo effects of medium chain-triglycerides (MCT)-coconut oil (MCO) and its combination with licorice extract (LE-MCO) on serum lipid profile, hepatic steatosis, and local fat pad proteins in diet-induced obese mice. No liver toxicity was observed in 45% fat diet (HFD)-fed mice orally treated with LE, MCO, and LE-MCO for 12 weeks. Their supplementation reduced HFD-enhanced body weight, blood glucose, and insulin in mice. Plasma levels of both PLTP and LCAT were boosted in LE-MCO-administered mice. Supplementation of LE-MCO diminished plasma levels of TG and TC with concomitant reduction of the LDL-C level and tended to raise blood HDL-C level compared to that of HFD alone-mice. Treatment of LE-MCO encumbered the hepatic induction of hepatosteatosis-related proteins of SREBP2, SREBP1c, FAS, ACC, and CD36 in HFD-fed mice. Substantial suppression of this induction was also observed in the liver of mice treated with MCO. Oral administration of LE-MCO to HFD mice boosted hepatic activation of AMPK and the induction of UCP-1 and FATP1 in brown fat. Conversely, LE-MCO disturbed hepatic PPAR-LXR-RXR signaling in HFD-fed animals and reversed HFD-elevated epididymal PPARγ. Collectively, oral administration of LE-MCO may impede hyperlipidemia and hepatosteatosis through curtailing hepatic lipid synthesis.

2-Bromo-4'-methoxychalcone and 2-Iodo-4'-methoxychalcone Prevent Progression of Hyperglycemia and Obesity via 5'-Adenosine-Monophosphate-Activated Protein Kinase in Diet-Induced Obese Mice

Obesity and diabetes are global health-threatening issues. Interestingly, the mechanism of these pathologies is quite different among individuals. The discovery and development of new categories of medicines from diverse sources are urgently needed for preventing and treating diabetes and other metabolic disorders. Previously, we reported that chalcones are important for preventing biological disorders, such as diabetes. In this study, we demonstrate that the synthetic halogen-containing chalcone derivatives 2-bromo-4′-methoxychalcone (compound 5) and 2-iodo-4′-methoxychalcone (compound 6) can promote glucose consumption and inhibit cellular lipid accumulation via 5′-adenosine-monophosphate-activated protein kinase (AMPK) activation and acetyl-CoA carboxylase 1 (ACC) phosphorylation in 3T3-L1 adipocytes and C2C12 skeletal myotubes. In addition, the two compounds significantly prevented body weight gain and impaired glucose tolerance, hyperinsulinemia, and insulin resistance, which collectively help to delay the progression of hyperglycemia in high-fat-diet-induced obese C57BL/6 mice. These findings indicate that 2-bromo-4′-methoxychalcone and 2-iodo-4′-methoxychalcone could act as AMPK activators, and may serve as lead compounds for a new class of medicines that target obesity and diabetes.

Isoliquiritigenin blunts osteoarthritis by inhibition of bone resorption and angiogenesis in subchondral bone

Isoliquiritigenin (ISL), a natural flavonoid extracted from licorice, has been demonstrated to exert attenuation of osteoclastogenesis and anti-angiogenesis activity in a wide variety of cells. Here, we first evaluated the effects of ISL on pathogenesis of osteoarthritis in a mouse model of OA. The data showed that ISL blunted progression of OA and lowered the Osteoarthritis Research Society International (OARSI)-Modified Making Score and protected the articular cartilage. The thickness of calcified cartilage zone was significantly decreased in ISL-treated ACLT mice compared with vehicle group. ISL increased expression level of lubricin and decreased collagen X (Col X), matrix metalloproteinase-13 (MMP-13). Moreover, ISL reduced aberrant active subchondral bone remodelling, including lowered trabecular pattern factor (Tb.pf) and increased bone volume/tissue volume (BV/TV, %) and thickness of subchondral bone plate (SBP) compared with vehicle-treated group. The results of immunostaining further revealed that ISL directly reduced RANKL-RANK-TRAF6 singling pathway induced osteoclastogenesis, prevented abnormal bone formation through indirect inhibition of TGF-β release. Additionally, ISL exerts anti-angiogenesis effects in subchondral bone through direct suppression of MMP-2. These results indicated that ISL attenuates progression of OA by inhibition of bone resorption and angiogenesis in subchondral bone, indicating that this may be a potential preventive therapy for OA.

Purple corn anthocyanins retard diabetes-associated glomerulosclerosis in mesangial cells and db/db mice

PURPOSE

Diabetic glomerulosclerosis is the hardening of the renal glomeruli that can lead to kidney failure. In the early stage of glomerulosclerosis occur renal mesangial expansion and renal filtration dysfunction. Purple corn has been classified as a functional food and is rich in anthocyanins exerting potential disease-preventive activities. The in vitro study using human renal mesangial cells examined that anthocyanin-rich purple corn butanol fraction (PCB) can attenuate high glucose (HG)-promoted mesangial cell proliferation and matrix accumulation.

METHODS

Cells were cultured for 3 days in media containing 33 mM glucose in the presence of 1-20 μg/mL PCB. In the in vivo animal study, db/db mice were treated with 10 mg/kg anthocyanin-rich polyphenolic extracts of purple corn (PCE) for 8 weeks.

RESULTS

HG enhanced mesangial production of the fibrosis biomarkers of collagen IV and connective tissue growth factor (CTGF), which was markedly attenuated by adding PCB. Such mesangial fibrosis entailed interleukin-8 activation via eliciting Tyk2-STAT signaling pathway. PCB dampened HG-promoted mesangial hyperplasia that appeared to be attributed to increased expression of platelet-derived growth factor. The 8-week administration of PCE lowered plasma glucose level of db/db mice and ameliorated severe albuminuria. Moreover, PCE lessened collagen fiber accumulation in kidney glomeruli and CTGF expression via retarding TGF-β signaling. Protein expressions of nephrin and podocin, key proteins for filtration barrier function of the glomerular capillary wall, were repressed by treating mice with PCE.

CONCLUSION

Purple corn may be a potent therapeutic agent for the treatment for diabetes-associated glomerulosclerosis accompanying proteinuria and kidney filtration dysfunction.

Reinvestigation of the synthesis of isoliquiritigenin: application of Horner-Wadsworth-Emmons reaction and Claisen-Schmidt condensation

Isoliquiritigenin [ILG, (E)-1] was readily prepared via the Horner-Wadsworth-Emmons reactions using β-ketophosphonates 5a, b. An improved protocol for the synthesis of (E)-1 via the Claisen-Schmidt condensation was also presented.

Fluorofenidone attenuates diabetic nephropathy and kidney fibrosis in db/db mice

BACKGROUND/AIMS

Fluorofenidone [1-(3-fluorophenyl)-5-methyl-2-(1H)-pyridone, AKF-PD], a novel pyridone agent, showed potent antifibrotic properties. The aim of the present study was to investigate the effects of AKF-PD on diabetic nephropathy and kidney fibrosis, and to obtain an insight into its mechanisms of action.

METHODS

We administered AKF-PD to diabetic db/db mice for 12 weeks. Moreover, we performed in vitro cultures using murine mesangial cells exposed to high ambient glucose concentrations.

RESULTS

AKF-PD reduced renal hypertrophy, mesangial matrix expansion and albuminuria in the db/db mice. The upregulated expression of α₁(I)- and α₁(IV)-collagen and fibronectin mRNAs, transforming growth factor-β1 (TGF-β₁), α-smooth muscle actin (α-SMA), and tissue inhibitors of metalloproteinase 1 (TIMP-1) mRNAs and proteins was inhibited by AKF-PD treatment in the renal cortex of db/db mice. The maximal effective dose of AKF-PD was about 500 mg/kg body weight. AKF-PD inhibited the upregulated expression of α₁(I)- and α₁(IV)-collagens, TGF-β₁, TIMP-1 and α-SMA induced by high glucose concentrations in cultured mesangial cells.

CONCLUSIONS

Our data indicate that AKF-PD diminishes the abnormal accumulation of mesangial matrix through the inhibition of upregulated expression of TGF-β target genes in kidneys of db/db mice, resulting in attenuation of renal fibrosis and amelioration of renal dysfunction despite persistent hyperglycemia. Therefore, AKF-PD, a potent antifibrotic agent, holds great promise in the treatment of diabetic nephropathy.

Effects of Panax notoginoside on the expression of TGF-β1 and Smad-7 in renal tissues of diabetic rats

In order to explore the effects of Panax notoginoside (PNS) on the expression of transforming growth factor β1 (TGF-β1) and Smad-7 in renal tissues of diabetes, a rat model of diabetic nephropathy was set up by intravenous injection of streptozotocin (STZ). Wistar rats were randomly divided into normal group, diabetic control group, group treated by PNS at low-dosage (PL), group treated by PNS at high-dosage (PH) and group treated by catopril (C), respectively. Fasting blood glucose (FBG), renal index, endogenous creatinine clearance rate (C(Cr)) and urinary albumin (UAlb) in 24 h were examined after 6 weeks. Meanwhile, the expressions of TGF-β1 and Smad7 in renal tissues were immunohistochemically dectected. At the end of the sixth week, FBG, renal index, C(cr), UAlb were all elevated significantly in control group (P<0.01). The expression of TGF-β1 protein was increased while Smad7 protein decreased in renal tissue (P<0.01). However, the treatment with PNS reversed the aforementioned changes in renal tissues of diabetic rats. These results indicate that PNS possess a protective effect on the kidney of diabetic rats and it might protect kidney by inhibiting the expression of TGF-β1 protein and enhancing the expression of Smad7 protein.

Isoangustone A suppresses mesangial fibrosis and inflammation in human renal mesangial cells

Development of diabetic nephropathy with fibrosis is associated with hypereglycemia-linked inflammation. Increased levels of proinflammatory factors have been found in diabetic patients with nephropathy. The present study was to test the hypothesis that isoangustone A, a novel compound present in licorice, can inhibit renal fibrosis and inflammation inflamed by high glucose (HG) in human mesangial cells through disturbing transforming growth factor β (TGF- β) and nuclear facor κB (NF- κB) pathways. Serum-starved mesangial cells were cultured in 33 mmol/L glucose media. Cells were treated with 1–20 μmol/L isoangustone A isolated from Glycyrrhiza uralensis licorice for three days. Exposure of cells to HG elevated connective tissue growth factor and collagen production, which was dose-dependently reversed by isoangustone A. Isoangustone A boosted HG-plummeted membrane type matrix metalloproteinase (MMP)-1 expression and diminished HG-elevated tissue inhibitor of MMP-2 expression. HG activated mesangial TGF- β1-SMAD-responsive signaling, which was repealed by ≥10 μmol/L isoangustone A. Furthermore, HG upregulated intracellular cell adhesion molecule-1 (ICAM-1) level and monocyte chemoattractant protein-1 (MCP-1) mRNA expression, and such increases were dose-dependently suppressed by isoangustone A most likely through hampering TGF- β signaling pathways. Blockade of NF- κB signaling appeared to be responsible for attenuating HG-triggered induction of ICAM-1 and MCP-1. Our findings provide the first evidence that isoangustone A dampens mesangial sclerosis associated with inflammation in response to HG through hindering TGF- β and NF- κB signaling.

Oleanolic acid reduces markers of differentiation in 3T3-L1 adipocytes

Oleanolic acid is a triterpenoid compound that is widely present in vegetables, medicinal herbs, and other plants and has potent antioxidant and antiinflammatory properties. However, the potential of oleanolic acid to offset obesity is not clear. This study tested the hypothesis that oleanolic acid suppresses the differentiation of 3T3-L1 adipocytes by downregulating cellular induction of peroxisome proliferators-activated receptor γ (PPARγ) and cytidine-cytidine-adenosine-adenosine-thymidine (CCAAT) enhancer binding protein α (C/EBPα). The 3T3-L1 adipocytes were cultured and differentiated in Dulbecco modified Eagle medium containing 10% fetal bovine serum for 6 to 8 days in the absence and presence of 1 to 25 μmol/L oleanolic acid according to differentiating protocols. Nontoxic oleanolic acid, at 25 μmol/L or less, dose-dependently attenuated lipid accumulation in differentiated adipocytes as evidenced by Oil Red O staining. Western blot analysis showed that the induction of PPARγ and C/EBPα was markedly attenuated in differentiated and oleanolic acid-treated adipocytes at their transcriptional messenger RNA levels. Furthermore, this study examined whether oleanolic acid dampened the induction of visfatin, a proinflammatory and visceral fat-specific adipokine expressed in adipocytes. Visfatin expression was inhibited in differentiated adipocytes exposed to a PPARγ inhibitor GW9662. In addition, the visfatin production was significantly repressed in 25 μmol/L oleanolic acid-treated adipocytes, possibly through blocking PPARγ activation. These results demonstrate that oleanolic acid may be a promising agent to disturb adipocyte differentiation and suppress obesity-associated inflammation.

The protective role of Smad7 in diabetic kidney disease: mechanism and therapeutic potential

OBJECTIVE

Although Smad3 has been considered as a downstream mediator of transforming growth factor-β (TGF-β) signaling in diabetes complications, the role of Smad7 in diabetes remains largely unclear. The current study tests the hypothesis that Smad7 may play a protective role and has therapeutic potential for diabetic kidney disease.

RESEARCH DESIGN AND METHODS

Protective role of Smad7 in diabetic kidney disease was examined in streptozotocin-induced diabetic mice that have Smad7 gene knockout (KO) and in diabetic rats given Smad7 gene transfer using an ultrasound-microbubble-mediated technique.

RESULTS

We found that mice deficient for Smad7 developed more severe diabetic kidney injury than wild-type mice as evidenced by a significant increase in microalbuminuria, renal fibrosis (collagen I, IV, and fibronectin), and renal inflammation (interleukin-1β [IL-1β], tumor necrosis factor-α [TNF-α], monocyte chemoattractant protein-1 [MCP-1], intracellular adhesion molecule-1 [ICAM-1], and macrophages). Further studies revealed that enhanced renal fibrosis and inflammation in Smad7 KO mice with diabetes were associated with increased activation of both TGF-β/Smad2/3 and nuclear factor-κB (NF-κB) signaling pathways. To develop a therapeutic potential for diabetic kidney disease, Smad7 gene was transferred into the kidney in diabetic rats by an ultrasound-microbubble-mediated technique. Although overexpression of renal Smad7 had no effect on levels of blood glucose, it significantly attenuated the development of microalbuminuria, TGF-β/Smad3-mediated renal fibrosis such as collagen I and IV and fibronectin accumulation and NF-κB/p65-driven renal inflammation including IL-1β, TNF-α, MCP-1, and ICAM-1 expression and macrophage infiltration in diabetic rats.

CONCLUSIONS

Smad7 plays a protective role in diabetic renal injury. Overexpression of Smad7 may represent a novel therapy for the diabetic kidney complication.

PI3K/Akt pathway mediates high glucose-induced lipogenesis and extracellular matrix accumulation in HKC cells through regulation of SREBP-1 and TGF-β1

Previous studies have shown that high glucose stimulates renal SREBP-1 gene expression and increases renal tubular cells lipid metabolism, however, the mechanisms remain elusive. In the present study we demonstrated that PI3K/Akt pathway was activated in human renal proximal tubular cell line (HKC) exposed to high glucose accompanied with up-regulation of SREBP-1, TGF-β1, lipid droplets deposits and extracellular matrix production. Inhibition of PI3K/Akt pathway by chemical LY294002 or specific short hairpin RNA (shRNA) vector prevented SREBP-1 and TGF-β1 up-regulation, as well as ameliorated HKC cells lipogenesis and extracellular matrix accumulation. These findings indicate that PI3K/Akt pathway potentially mediates high glucose-induced lipogenesis and extracellular matrix accumulation in HKC cells.