18β-Glycyrrhetinic acid monoglucuronide (GAMG) alleviates single-walled carbon nanotubes (SWCNT)-induced lung inflammation and fibrosis in mice through PI3K/AKT/NF-κB signaling pathway

Targeting myocardial inflammation: investigating the therapeutic potential of atrial natriuretic peptide in atrial fibrosis

BACKGROUND

Atrial Fibrillation (AF), a prevalent arrhythmic condition, is intricately associated with atrial fibrosis, a major pathological contributor. Central to the development of atrial fibrosis is myocardial inflammation. This study focuses on Atrial Natriuretic Peptide (ANP) and its role in mitigating atrial fibrosis, aiming to elucidate the specific mechanisms by which ANP exerts its effects, with an emphasis on fibroblast dynamics.

METHODS AND RESULTS

The study involved forty Sprague-Dawley rats, divided into four groups: control, Angiotensin II (Ang II), Ang II + ANP, and ANP only. The administration of 1 µg/kg/min Ang II was given to Ang II and Ang II + ANP groups, while both Ang II + ANP and ANP groups received 0.1 µg/kg/min ANP intravenously for a duration of 14 days. Cardiac fibroblasts were used for in vitro validation of the proposed mechanisms. The study observed that rats in the Ang II and Ang II + ANP groups showed an increase in blood pressure and a decrease in body weight, more pronounced in the Ang II group. Diastolic dysfunction, a characteristic of the Ang II group, was alleviated by ANP. Additionally, ANP significantly reduced Ang II-induced atrial fibrosis, myofibroblast proliferation, collagen overexpression, macrophage infiltration, and the elevated expression of Interleukin 6 (IL-6) and Tenascin-C (TN-C). Transcriptomic sequencing indicated enhanced PI3K/Akt signaling in the Ang II group. Furthermore, in vitro studies showed that ANP, along with the PI3K inhibitor LY294002, effectively reduced PI3K/Akt pathway activation and the expression of TN-C, collagen-I, and collagen-III, which were induced by Ang II.

CONCLUSIONS

The study demonstrates ANP's potential in inhibiting myocardial inflammation and reducing atrial fibrosis. Notably, ANP's effect in countering atrial fibrosis seems to be mediated through the suppression of the Ang II-induced PI3K/Akt-Tenascin-C signaling pathway. These insights enhance our understanding of AF pathogenesis and position ANP as a potential therapeutic agent for treating atrial fibrosis.

Carbon black nanoparticles and cadmium co-exposure aggravates bronchial epithelial cells inflammation via autophagy-lysosome pathway

Carbon black nanoparticles (CBNPs) and cadmium (Cd) are major components of various air pollutants and cigarette smoke. Autophagy and inflammation both play critical roles in understanding the toxicity of particles and their components, as well as maintaining body homeostasis. However, the effects and mechanisms of CBNPs and Cd (CBNPs-Cd) co-exposure on the human respiratory system remain unclear. In this study, a CBNPs-Cd exposure model was constructed to explore the respiratory toxicity and combined mechanism of these chemicals on the autophagy-lysosome pathway in the context of respiratory inflammation. Co-exposure of CBNPs and Cd significantly increased the number of autophagosomes and lysosomes in human bronchial epithelial cells (16HBE) and mouse lung tissues compared to the control group, as well as the groups exposed to CBNPs and Cd alone. Autophagic markers, LC3II and P62 proteins, were up-regulated in 16HBE cells and mouse lung tissues after CBNPs-Cd co-exposure. However, treatment with Cq inhibitor (an indicator of lysosomal acid environment) resulted in a substantial decreased co-localization fluorescence of LC3 and lysosomes in the CBNPs-Cd combination group compared with the CBNPs-Cd single and control groups. No difference in LAMP1 protein expression was observed among the exposed groups. Adding 3 MA alleviated inflammatory responses, while applying the Baf-A1 inhibitor aggravated inflammation both in vitro and in vivo following CBNPs-Cd co-exposure. Factorial analysis showed no interaction between CBNPs and Cd in their effects on 16HBE cells. We demonstrated that co-exposure to CBNPs-Cd increases the synthesis of autophagosomes and regulates the acidic environment of lysosomes, thereby inhibiting autophagy-lysosome fusion and enhancing the inflammatory response in both 16HBE cells and mouse lung. These findings provide evidence for a comprehensive understanding of the interaction between CBNPs and Cd in mixed pollutants, as well as for the prevention and control of occupational exposure to these two chemicals.

TRPV2 inhibitor tranilast prevents atrial fibrillation in rat models of pulmonary hypertension

Atrial fibrillation (AF) is common in pulmonary hypertension (PH), whereas the mechanisms and treatments remain to be explored. TRPV2 regulates the structure and function of the cardiovascular system; however, little attention has been given to its role in AF. This study was to determine whether TRPV2 was involved in PH-induced AF and the effects of TRPV2 inhibitor tranilast on AF in rat models of PH. Monocrotaline (MCT) and SU5416/hypoxia (SuHx)-induced PH models were performed to detect atrial electrophysiological parameters. Daily tranilast (a TRPV2 inhibitor) or saline was given starting 1 day before PH establishment. PH increased the susceptibility to AF, with TRPV2 up-regulated in the right atria. Compared to PH rats, tranilast reduced AF inducibility and the prolongations of ERP and APD; mitigated cardiopulmonary remodeling and the increases in P-wave duration and P-R interval; partially reversed the down-regulation of ion channels such as Cav1.2, Nav1.5, Kv4.3, Kv4.2, Kv1.5, Kir2.1, Kir3.1, Kir3.4 as well as connexin (Cx) 40 and Cx43; improved right atrial (RA) fibrosis, enlargement, and myocardial hypertrophy; decreased the accumulation of inflammatory cells; down-regulated inflammatory indicators such as TNF-α, IL-1β, CXCL1, and CXCL2; and inhibited the activation of the PI3K-AKT-NF-κB signaling pathway. Our results reveal that TRPV2 participates in PH-induced AF, and TRPV2 inhibitor tranilast prevents PH-induced RA remodeling. TRPV2 might be a promising target for PH-induced AF.

Intervention effects and related mechanisms of glycyrrhizic acid on zebrafish with Hirschsprung-associated enterocolitis

BACKGROUND

The prevention and treatment of Hirschsprung-associated enterocolitis (HAEC) is a serious challenge in pediatric surgery. Exploring the mechanism of HAEC is conducive to the prevention of this disease.

AIM

To explore the possible mechanism of glycyrrhizic acid (GA) and its therapeutic effect on HAEC.

METHODS

We developed a model of enteritis induced by trinitrobenzenesulfonic acid (TNBS) in zebrafish, and treated it with different concentrations of GA. We analyzed the effect of GA on the phenotype and inflammation of zebrafish.

RESULTS

After treatment with TNBS, the area of the intestinal lumen in zebrafish was significantly increased, but the number of goblet cells in the intestinal lumen was significantly reduced, but these did not increase the mortality of zebrafish, indicating that the zebrafish enteritis model was successfully developed. Different concentrations of GA protected zebrafish with enteritis. In particular, high concentrations of GA were important for the prevention and control of HAEC because it significantly reduced the intestinal luminal area, increased the number of goblet cells in the intestinal lumen, and reduced the levels of interleukin (IL)-1β and IL-8.

CONCLUSION

GA significantly reduced the intestinal luminal area, increased the number of intestinal goblet cells, and decreased IL-1β and IL-8 in zebrafish, and is important for prevention and control of HAEC.

18-α-glycyrrhetinic acid alleviates oxidative damage in periodontal tissue by modulating the interaction of Cx43 and JNK/NF-κB pathways

Objective: Periodontitis is a common chronic inflammatory disease in which oxidative stress is one of the key pathogenic factors. Connexin43 (Cx43) is the most critical and widely distributed connexin isoform. When the organism undergoes a severe and sustained stress response, Cx43-mediated gap junctions (GJs) are believed to underlie the biology of tissue injury exacerbation and amplification. Notably, 18-α-glycyrrhetinic acid (GA) is a classical pharmacological inhibitor of GJs and has antioxidant potential. However, the regulatory role of GA in the redox signaling of periodontal tissues and the potential mechanisms of Cx43 in the pathogenesis of periodontitis remain uncertain. Methods: In this study, we evaluated the effects and mechanisms of GA in alleviating oxidative damage of periodontal tissues and cells by constructing an H2O2-induced oxidative stress model in human periodontal ligament cells (hPDLCs) and a periodontitis model in rats. Results: Cellular experiments showed that GA effectively attenuated H2O2-induced oxidative damage in hPDLCs by inhibiting the expression and function of Cx43. In addition, pretreatment of hPDLCs with either GA or SP600125 (a JNK inhibitor) inhibited the Cx43/JNK/NF-κB pathway, restored cell viability, and reduced apoptosis. Animal experiment results showed that GA intervention reduced alveolar bone resorption and periodontal tissue destruction, inhibited osteoclast differentiation, improved mitochondrial structural abnormalities and dysfunction in periodontal tissue, and decreased oxidative stress levels and apoptosis in rats with periodontitis. Conclusion: Overall, our findings suggest that the Cx43/JNK/NF-κB pathway may play a vital role to promote periodontitis progression, while GA reduces oxidative stress and apoptosis by inhibiting the interaction of Cx43 and JNK/NF-κB pathways, thus alleviating oxidative damage in the periodontal tissues.

Lung inflammation perturbation by engineered nanoparticles

In recent years, the unique and diverse physicochemical properties of nanoparticles have brought about their wide use in many fields; however, it is necessary to better understand the possible human health risks caused by their release in the environment. Although the adverse health effects of nanoparticles have been proposed and are still being clarified, their effects on lung health have not been fully studied. In this review, we focus on the latest research progress on the pulmonary toxic effects of nanoparticles, and we summarized their disturbance of the pulmonary inflammatory response. First, the activation of lung inflammation by nanoparticles was reviewed. Second, we discussed how further exposure to nanoparticles aggravated the ongoing lung inflammation. Third, we summarized the inhibition of the ongoing lung inflammation by nanoparticles loaded with anti-inflammatory drugs. Forth, we introduced how the physicochemical properties of nanoparticles affect the related pulmonary inflammatory disturbance. Finally, we discussed the main gaps in current research and the challenges and countermeasures in future research.

TMT proteomics analysis reveals the mechanism of bleomycin-induced pulmonary fibrosis and effects of Ginseng honeysuckle superfine powdered tea

BACKGROUND

Pulmonary fibrosis (PF) is a chronic and potentially fatal lung disease and disorder. Although the active ingredients of ginseng honeysuckle superfine powdered tea (GHSPT) have been proven to have anti-inflammatory and antioxidant effects, the mechanism of GHSPT on PF remains unclear. The present study was to explore the underlying mechanism of GHSPT in treating PF based on proteomics and network pharmacology analysis and to confirm it in vivo.

MATERIALS AND METHODS

We used intratracheal instillation of bleomycin to induce the PF mouse model and GHSPT (640 mg/kg) intragastrically administrated to PF mice for 21 days. The lung tissues were harvested for TMT-based proteomics. The UPLC-Q-Exactive MS/MS analyze the serum migrant compounds of GHSPT in the PF mice. Moreover, components of GHSPT were harvested from the pharmacology database of the TCMSP system. PF-related targets were retrieved using NCBI and GeneCards databases.

RESULTS

Our results showed that GHSPT significantly alleviated PF mice. Proteomics analysis showed that 525 proteins had significantly changed in the lung of untreated PF mice. Among them, 19 differential proteins were back-regulated to normal levels after GHSPT therapy. Moreover, 25 compounds originating from GHSPT were identified in the serum sample. Network analysis showed 159 active ingredients and 92 drug targets against PF. The signaling pathways include apoptosis, ferroptosis, cytokine-cytokine receptor, P53, and PI3K-Akt signaling pathway.

CONCLUSION

The evidence suggests that GHSPT might play an effective role in the treatment of PF by multi-target interventions against multiple signaling pathways.

A Review of the Antiviral Activities of Glycyrrhizic Acid, Glycyrrhetinic Acid and Glycyrrhetinic Acid Monoglucuronide

Licorice, a natural medicine derived from the roots and rhizomes of Glycyrrhiza species, possesses a wide range of therapeutic applications, including antiviral properties. Glycyrrhizic acid (GL) and glycyrrhetinic acid (GA) are the most important active ingredients in licorice. Glycyrrhetinic acid 3-O-mono-β-d-glucuronide (GAMG) is the active metabolite of GL. GL and its metabolites have a wide range of antiviral activities against viruses, such as, the hepatitis virus, herpes virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and so on. Although their antiviral activity has been widely reported, the specific mechanism of action involving multiple links such as the virus itself, cells, and immunity are not clearly established. In this review, we will give an update on the role of GL and its metabolites as antiviral agents, and detail relevant evidence on the potential use and mechanisms of actions. Analyzing antivirals, their signaling, and the impacts of tissue and autoimmune protection may provide promising new therapeutic strategies.

Pharmacological Features of 18β-Glycyrrhetinic Acid: A Pentacyclic Triterpenoid of Therapeutic Potential

Glycyrrhiza glabra L. (belonging to the family Leguminosae), commonly known as Licorice, is a popular medicinal plant that has been used in traditional medicine worldwide for its ethnopharmacological efficacy in treating several ailments. Natural herbal substances with strong biological activity have recently received much attention. The main metabolite of glycyrrhizic acid is 18β-glycyrrhetinic acid (18βGA), a pentacyclic triterpene. A major active plant component derived from licorice root, 18βGA has sparked a lot of attention due to its pharmacological properties. The current review thoroughly examines the literature on 18βGA, a major active plant component obtained from Glycyrrhiza glabra L. The current work provides insight into the pharmacological activities of 18βGA and the potential mechanisms of action involved. The plant contains a variety of phytoconstituents such as 18βGA, which has a variety of biological effects including antiasthmatic, hepatoprotective, anticancer, nephroprotective, antidiabetic, antileishmanial, antiviral, antibacterial, antipsoriasis, antiosteoporosis, antiepileptic, antiarrhythmic, and anti-inflammatory, and is also useful in the management of pulmonary arterial hypertension, antipsychotic-induced hyperprolactinemia, and cerebral ischemia. This review examines research on the pharmacological characteristics of 18βGA throughout recent decades to demonstrate its therapeutic potential and any gaps that may exist, presenting possibilities for future drug research and development.

Impaired autophagy-accelerated senescence of alveolar type II epithelial cells drives pulmonary fibrosis induced by single-walled carbon nanotubes

BACKGROUND

The rapid increase in production and application of carbon nanotubes (CNTs) has led to wide public concerns in their potential risks to human health. Single-walled CNTs (SWCNTs), as an extensively applied type of CNTs, have shown strong capacity to induce pulmonary fibrosis in animal models, however, the intrinsic mechanisms remain uncertain.

RESULTS

In vivo experiments, we showed that accelerated senescence of alveolar type II epithelial cells (AECIIs) was associated with pulmonary fibrosis in SWCNTs-exposed mice, as well as SWCNTs-induced fibrotic lungs exhibited impaired autophagic flux in AECIIs in a time dependent manner. In vitro, SWCNTs exposure resulted in profound dysfunctions of MLE-12 cells, characterized by impaired autophagic flux and accelerated cellular senescence. Furthermore, the conditioned medium from SWCNTs-exposed MLE-12 cells promoted fibroblast-myofibroblast transdifferentiation (FMT). Additionally, restoration of autophagy flux with rapamycin significantly alleviated SWCNTs-triggered senescence and subsequent FMT whereas inhibiting autophagy using 3-MA aggravated SWCNTs-triggered senescence in MLE-12 cells and FMT.

CONCLUSION

SWCNTs trigger senescence of AECIIs by impairing autophagic flux mediated pulmonary fibrosis. The findings raise the possibility of senescence-related cytokines as potential biomarkers for the hazard of CNTs exposure and regulating autophagy as an appealing target to halt CNTs-induced development of pulmonary fibrosis.

Physiology-Based Pharmacokinetic Study on 18β-Glycyrrhetic Acid Mono-Glucuronide (GAMG) Prior to Glycyrrhizin in Rats

To understand that 18β-Glycyrrhetic acid 3-O-mono-β-D-glucuronide (GAMG) showed better pharmacological activity and drug-like properties than 18β-Glycyrrhizin (GL); a rapid and sensitive HPLC-MS/MS method was established for the simultaneous determination of GAMG and its metabolite 18β-Glycyrrhetinic acid (GA) in rat plasma and tissues after oral administration of GAMG or GL. This analytical method was validated by linearity, LLOQ, specificity, recovery rate, matrix effect, etc. After oral administration, GAMG exhibited excellent C_max (2377.57 ng/mL), T_max (5 min) and AUC_0-T (6625.54 mg/L*h), which was much higher than the C_max (346.03 ng/mL), T_max (2.00 h) and AUC_0-T (459.32 mg/L*h) of GL. Moreover, GAMG had wider and higher tissue distribution in the kidney, spleen, live, lung, brain, etc. These results indicated that oral GAMG can be rapidly and efficiently absorbed and be widely distributed in tissues to exert stronger and multiple pharmacological activities. This provided a physiological basis for guiding the pharmacodynamic study and clinical applications of GAMG.