Anti-inflammatory effects of ginsenoside Rg3 on the hypertrophic scar formation via the NF-κB/IκB signaling pathway in rabbit ears

Repressing effect of transformed ginsenoside Rg3-mix against LPS-induced inflammation in RAW264.7 macrophage cells

BACKGROUND

Rg3-ginsenoside, a protopanaxadiol saponin, is a well-known adaptogen used for the prevention of cancer and inflammation. However, despite its distinct biological activity, the concentration of Rg3 in the total ginseng extract is insufficient for therapeutic applications. This study aims to convert PPD-class of major ginsenosides into a mixture of minor ginsenoside, to analyze its immune-regulatory role in macrophage cells.

RESULTS

Using heat and organic acid treatment, three major ginsenosides, Rc, Rd, and Rb1, were converted into a mixture of minor ginsenosides, GRg3-mix [Rg3(S), Rg3(R), Rg5, and Rk1]. Purity and content analysis of the transformed compound were performed using thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC), compared with their standards. Preceding with the anti-inflammatory activity of GRg3-mix, lipopolysaccharide (LPS)-stimulated murine RAW264.7 macrophage cells were treated with various concentrations of GRg3-mix (6.25, 12.5, 25, and 50 μg/mL). The cell viability assay revealed that the level of cell proliferation was increased, while the nitric oxide (NO) assay showed that NO production decreased dose-dependently in activated RAW264.7 cells. The obtained results were compared to those of pure Rg3(S) ≥ 98% (6.25, 12.5, and 25 μg/mL). Preliminary analysis of the CCK-8 and NO assay demonstrated that GRg3-mix can be used as an anti-inflammatory mediator, but mRNA and protein expression levels were evaluated for further confirmation. The doses of GRg3-mix significantly suppressed the initially upregulated mRNA and protein expression of inflammation-related enzymes and cytokines, namely inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), nuclear transcription factor kappa B (NF-κB), tumor necrosis factor (TNF-α), and interleukins (IL-6 and IL1B), as measured by reverse transcription-polymerase chain reaction and western blotting.

CONCLUSIONS

Our pilot data confirmed that the mixture of minor ginsenosides, namely GRg3-mix, has high anti-inflammatory activity and has an easy production procedure.

Pharmacological properties, molecular mechanisms and therapeutic potential of ginsenoside Rg3 as an antioxidant and anti-inflammatory agent

Inflammation and oxidative stress lead to various acute or chronic diseases, including pneumonia, liver and kidney injury, cardiovascular and cerebrovascular diseases, metabolic diseases, and cancer. Ginseng is a well-known and widely used ethnic medicine in Asian countries, and ginsenoside Rg3 is a saponin isolated from Panax ginseng C. A. Meyer, Panax notoginseng, or Panax quinquefolius L. This compound has a wide range of pharmacological properties, including antioxidant and anti-inflammatory activities, which have been evaluated in disease models of inflammation and oxidative stress. Rg3 can attenuate lung inflammation, prevent liver and kidney function damage, mitigate neuroinflammation, prevent cerebral and myocardial ischemia–reperfusion injury, and improve hypertension and diabetes symptoms. The multitarget, multipathway mechanisms of action of Rg3 have been gradually deciphered. This review summarizes the existing knowledge on the anti-inflammatory and antioxidant effects and underlying molecular mechanisms of ginsenoside Rg3, suggesting that ginsenoside Rg3 may be a promising candidate drug for the treatment of diseases with inflammatory and oxidative stress conditions.

Poloxamer 407 and Hyaluronic Acid Thermosensitive Hydrogel-Encapsulated Ginsenoside Rg3 to Promote Skin Wound Healing

Ginsenoside Rg3 has shown beneficial effects in various skin diseases. The current interest in designing and developing hydrogels for biomedical applications continues to grow, inspiring the further development of drug-loaded hydrogels for tissue repair and localized drug delivery. The aim of the present study was to develop an effective and safe hydrogel (Rg3-Gel), using ginsenoside Rg3, and we evaluated the wound-healing potential and therapeutic mechanism of Rg3-Gel. The results indicated that the optimized Rg3-Gel underwent discontinuous phase transition at low and high temperatures. Rg3-Gel also exhibited good network structures, swelling water retention capacity, sustainable release performance, and excellent biocompatibility. Subsequently, the good antibacterial and antioxidant properties of Rg3-Gel were confirmed by in vitro tests. In full-thickness skin defect wounded models, Rg3-Gel significantly accelerated the wound contraction, promoted epithelial and tissue regeneration, and promoted collagen deposition and angiogenesis. In addition, Rg3-Gel increased the expression of autophagy proteins by inhibiting the MAPK and NF-KB pathways in vivo. It simultaneously regulated host immunity by increasing the abundance of beneficial bacteria and the diversity of the wound surface flora. From these preliminary evaluations, it is possible to conclude that Rg3-Gel has excellent application potential in wound-healing drug delivery systems.

Phenols and terpenoids: natural products as inhibitors of NLRP3 inflammasome in cardiovascular diseases

Inflammatory infiltration has been implicated in the pathogenesis of cardiovascular diseases (CVDs). The NLRP3 inflammasome is involved in the development of several types of CVDs, including myocardial infarction, myocardial ischemia-reperfusion damage, heart failure, atrial fibrillation, and hypertension. Inhibiting the activity of NLRP3 inflammasome can inhibit the progress of CVDs. However, there is no NLRP3 inflammasome inhibitor in clinic, and it is very important to find a safe and effective NLRP3 inhibitor. Phenols and terpenoids are naturally natural products that have many anti-inflammatory effects in CVDs by modulating the NLRP3 inflammatory pathway. Thus, 20 natural products from phenols and terpenoids for the treatment of cardiovascular disease based on the inhibition of NLRP3 inflammasome were summarized and screened. Docking results showed salvianolic acid B and ellagic acid in phenols, and oridonin and triptolide in terpenoids had a better binding activity with NLRP3, which can provide theoretical support for finding novel NLRP3 inflammasome inhibitors or lead compounds in the future.

Ginsenoside Rg3 Alleviates Antithyroid Cancer Drug Vandetanib-Induced QT Interval Prolongation

Inhibition of human ether-a-go-go-related gene (hERG) potassium channel is responsible for acquired long QT syndromes, which leads to life-threatening cardiac arrhythmia. A multikinase inhibitor, vandetanib, prolongs the progression-free survival time in advanced medullary thyroid cancer. However, vandetanib has been reported to induce significant QT interval prolongation, which limits its clinical application. Some studies have showed that ginsenoside Rg3 decelerated hERG K(+) channel tail current deactivation. Therefore, in this study, we aim to confirm whether ginsenoside Rg3 targeting hERG K(+) channel could be used to reverse the vandetanib-induced QT interval prolongation. Electrocardiogram (ECG) and monophasic action potential (MAP) were recorded using electrophysiology signal sampling and analysis system in Langendorff-perfused rabbit hearts. The current clamp mode of the patch-clamp technique was used to record transmembrane action potential. The whole-cell patch-clamp technique was used to record the hERG K+ current. In Langendorff-perfused hearts, vandetanib prolonged the QT interval in a concentration-dependent manner with an IC50 of 1.96 μmol/L. In human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), vandetanib significantly prolonged the action potential duration at 50%, 70%, and 90% repolarization (APD50, APD70, and APD90). In stable transfected human hERG gene HEK293 cells, vandetanib caused concentrate-dependent inhibition in the step and tail currents of hERG. As expected, ginsenoside Rg3 relieved vandetanib-induced QT interval prolongation in Langendorff-perfused heart and reversed vandetanib-induced APD prolongation in hiPSC-CMs. Furthermore, ginsenoside Rg3 alleviated vandetanib-induced hERG current inhibition and accelerated the process of the channel activation. Ginsenoside Rg3 may be a promising cardioprotective agent against vandetanib-induced QT interval prolongation through targeting hERG channel. These novel findings highlight the therapeutic potential of ginsenoside to prevent vandetanib-induced cardiac arrhythmia.

Therapeutic Strategies by Regulating Interleukin Family to Suppress Inflammation in Hypertrophic Scar and Keloid

Hypertrophic scar (HS) and keloid are fibroproliferative disorders (FPDs) of the skin due to aberrant wound healing, which cause disfigured appearance, discomfort, dysfunction, psychological stress, and patient frustration. The unclear pathogenesis behind HS and keloid is partially responsible for the clinical treatment stagnancy. However, there are now increasing evidences suggesting that inflammation is the initiator of HS and keloid formation. Interleukins are known to participate in inflammatory and immune responses, and play a critical role in wound healing and scar formation. In this review, we summarize the function of related interleukins, and focus on their potentials as the therapeutic target for the treatment of HS and keloid.

Effect of THBS1 on the Biological Function of Hypertrophic Scar Fibroblasts

Hypertrophic scarring is a skin collagen disease that can occur following skin damage and is unlikely to heal or subside naturally. Since surgical treatment often worsens scarring, it is important to investigate the pathogenesis and prevention of hypertrophic scarring. Thrombospondin-1 (THBS1) is a matrix glycoprotein that can affect fibrosis by activating TGF-β1, which plays a key role in wound repair and tissue regeneration; therefore, we investigated the effects of THBS1 on the biological function of hypertrophic scar fibroblasts. THBS1 expression was measured in hypertrophic scars and adjacent tissues as well as normal fibroblasts, normal scar fibroblasts, and hypertrophic scar fibroblasts. In addition, THBS1 was overexpressed or silenced in hypertrophic scar fibroblasts to determine the effects of THBS1 on cell proliferation, apoptosis, and migration, as well as TGF-β1 expression. Finally, the role of THBS1 in hypertrophic scarring was confirmed in vivo using a mouse model. We found that THBS1 expression was increased in hypertrophic scar tissues and fibroblasts and promoted the growth and migration of hypertrophic scar fibroblasts as well as TGF-β1 expression. Interestingly, we found that si-THBS1 inhibited the occurrence and development of bleomycin-induced hypertrophic scars in vivo and downregulated TGF-β1 expression. Together, our findings suggest that THBS1 is abnormally expressed in hypertrophic scars and can induce the growth of hypertrophic scar fibroblasts by regulating TGF-β1. Consequently, THBS1 could be an ideal target for treating hypertrophic scarring.

Inhibition of sphingosine kinase 2 attenuates hypertrophic scar formation via upregulation of Smad7 in human hypertrophic scar fibroblasts

The aims of the present study were to investigate the role of sphingosine kinase 2 (Sphk2) in hypertrophic scar (HS) formation and its underlying mechanisms. The expression levels of Sphk2 and Smad7 in HS tissues and healthy skin tissues of patients undergoing plastic surgery were determined using immunohistochemical staining. Subsequently, the expression levels of Sphk2 and collagen I in human embryonic skin fibroblasts (control) and human HS fibroblasts (HSF) were detected using western blot analysis and immunofluorescence assay, respectively. Following Sphk2 silencing, Smad7 overexpression or both Sphk2 and Smad7 silencing, HSF proliferative ability was assessed using Cell Counting Kit‑8 assay and proliferation‑associated proteins were evaluated using western blot analysis. In addition, the level of apoptosis in HSF was assessed using flow cytometry and expression levels of apoptotic‑associated proteins were determined using western blotting. Furthermore, the expression levels of collagen I and proteins in the TGF‑β1/Smad signaling pathway were detected using western blot analysis. The results indicated that the expression of Sphk2 was significantly increased, while Smad7 expression was decreased in HS tissue. Moreover, the upregulation of Sphk2 and collagen I expression levels was identified in HSF. The present results also indicated that Sphk2 silencing or Smad7 overexpression inhibited proliferation, but promoted apoptosis of HSF, coupled with changes in the expression levels of proliferation‑associated proteins, with an increase in p21 and a decrease in cyclin D1 expression levels, and apoptosis‑associated proteins, with an increase in Bax and cleaved caspase‑3, and a decrease in Bcl‑2, which were reversed following transfection with both Sphk2 and Smad7 using small interfering RNA in HSF. In addition, the expression levels of transforming growth factor‑β1, phosphorylated (p)‑Smad2, p‑Smad3 and collagen I were reduced following Sphk2 silencing or Smad7 overexpression, which were abolished by silencing both Sphk2 and Smad7. Collectively, the present results indicated that inhibition of Sphk2 attenuated HS formation via upregulation of Smad7 expression, thus Sphk2 may serve as a potential therapeutic target for the treatment of HS.