Aegle marmelos extract rich in marmelosin exacted ameliorative effect against chromium-induced oxidative stress and apoptosis through regulation of Gadd45 in HepG2 cell line

DNA hypomethylation-mediated upregulation of GADD45B facilitates airway inflammation and epithelial cell senescence in COPD

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease typically characterized by chronic airway inflammation, with emerging evidence highlighting the driving role of cellular senescence-related lung aging. Accelerated lung aging and inflammation mutually reinforce each other, creating a detrimental cycle that contributes to disease progression. Growth arrest and DNA damage-inducible (GADD45) family has been reported to involve in multiple biological processes, including inflammation and senescence. However, the role of GADD45 family in COPD remains elusive.

OBJECTIVES

To investigate the role and mechanism of GADD45 family in COPD pathogenesis.

METHODS

Expressions of GADD45 family were evaluated by bioinformatic analysis combined with detections in clinical specimens. The effects of GADD45B on inflammation and senescence were investigated via constructing cell model with siRNA transfection or overexpression lentivirus infection and animal model with Gadd45b knockout. Targeted bisulfite sequencing was performed to probe the influence of DNA methylation in GADD45B expression in COPD.

RESULTS

GADD45B expression was significantly increased in COPD patients and strongly associated with lung function, whereas other family members presented no changes. GADD45B upregulation was confirmed in mice exposed by cigarette smoke (CS) and HBE cells treated by CS extract as well. Moreover, experiments involving bidirectional modulation of GADD45B expression in HBE cells further substantiated its positive regulatory role in inflammatory response and cellular senescence. Mechanically, GADD45B-facilitated inflammation was directly mediated by p38 phosphorylation, while GADD45B interacted with FOS to promote cellular senescence in a p38 phosphorylation-independent manner. Furthermore, Gadd45b deficiency remarkably alleviated inflammation and senescence of lungs in CS-exposed mice, as well as improved emphysema and lung function. Eventually, in vivo and vitro experiments demonstrated that GADD45B overexpression was partially mediated by CS-induced DNA hypomethylation.

CONCLUSION

Our findings have shed light on the impact of GADD45B in the pathogenesis of COPD, thereby offering a promising target for intervention in clinical settings.

Phytochemical Analysis and Evaluation of Antioxidant, Antidiabetic, and Anti-inflammatory Properties of Aegle marmelos and Its Validation in an In-Vitro Cell Model

INTRODUCTION

Persistent hyperglycemia significantly increases oxidative stress and inflammation resulting in multiple cellular and molecular alterations which further exacerbate the diabetes associated complications. Aegle marmelos (L.) Corrêa is a medicinal plant used in the Indian system of medicine for treating various disorders including diabetes. However, studies on phytoconstituents and their pharmacological activity of this plant are limited. Therefore, we aimed to determine the phytochemical components, evaluate the antidiabetic activity, anti-inflammatory activity, and antioxidant activity of A. marmelos leaf extract, and validate its mechanistic effects in an in vitro cell model.

METHODS

The qualitative and quantitative analysis of the different phytoconstituents in the extract was determined using standardized protocols. The antioxidant activity of the extract was evaluated by 2,2-di-phenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity assay and ferric reducing antioxidant power (FRAP) assay. The antidiabetic activity of the extract was evaluated by α-amylase inhibition and α-glucosidase inhibition assay. The anti-inflammatory activity was studied using an albumin denaturation assay. In addition, the pharmacological effect(s) of leaf extract was checked in the normal rat kidney fibroblast cells (NRK-49F) under high glucose conditions. Intracellular reactive oxygen species (ROS) generation was measured by fluorometry using fluorescence probe 2',7'-dichlorodihydrofluorescin diacetate (DCF-DA). mRNA expression of inflammatory markers including inducible nitric oxide synthase (iNOS) and tumor necrosis factor-alpha (TNF-α) was studied using real-time quantitative polymerase chain reaction (RT-qPCR). Cell migration was studied using cell scratch assay. Statistical analysis was performed using GraphPad Prism version 8.0.

RESULTS

The phytochemical analysis of A. marmelos leaf extract revealed the presence of alkaloids, phenols, flavonoids, and saponins. The extract showed higher antioxidant activity in the DPPH (IC50=258.21 µg/mL) and FRAP assay (IC50=293.83 µg/mL). The extract exhibited prominent antidiabetic activity by inhibiting enzymes α-Amylase (IC50=73.2 µg/mL) and α-glucosidase (IC50=43.9 µg/mL). In addition, the extract showed effective anti-inflammatory activity by significantly inhibiting the denaturation of egg albumin (IC50=102.8 µg/mL). Further, the leaf extract significantly decreased the high glucose-induced ROS generation as well as inflammatory markers in rat fibroblast cell lines in a dose-dependent manner. Additionally, high glucose-induced cell migration as the measure of cell injury was effectively reduced by the extract treatment.

CONCLUSION

 A. marmelos leaf extract was quantified to possess a substantial amount of important phytoconstituents that have promising pharmacological properties. Besides showing antidiabetic activity, the extract significantly combats the high glucose-induced ROS generation, inflammatory markers expressions, and cell migration. Further, in-depth studies and clinical trials are warranted so as to position these traditional remedies for the treatment of metabolic disorders.

Evaluation of the antioxidant activity, genotoxic, and cytotoxic effects of the ethanolic leaves extract of Abutilon hirtum (Lam.) Sweet using in vitro assays

Abutilon hirtum (Lam.) Sweet belongs to the Malvaceae family and is a perennial shrub commonly known as Indian mallow, which is distributed in tropical regions and many different areas in Saudi Arabia. A. hirtum is an economically and a medicinally useful plant in different zones of the world for healing various diseases. The current research explores the in vitro antioxidant characteristics and cytotoxic and genotoxic potential effects of the ethanolic leaf extract of A. hirtum (LEAH). Mitotic index (MI), micronucleus (MN), and chromosomal aberration (CA) tests were performed in Allium cepa, and MTT assays were performed using human dermal fibroblast, adult (HDFa) and breast cancer (MCF7) cell lines. The comet assay was used to assess the genotoxic effect of LEAH. The antioxidant activity of LEAH was evaluated by DPPH and superoxide anion free radical scavenging assays. The results revealed that the cytotoxic effects of LEAH on Allium cepa were significantly changed in an inverse relationship with MI (general average for 3 times 0.275) and a direct relationship with MNs and CAs against concentration and treatment time, for highest concentration 1.351 mg/ml were 0.74 and 1.81 respectively. In addition, the MTT test revealed a dose-dependent cytotoxic impact, with the % cell viability decreasing as the concentration of LEAH increased, the lowest % cell viability (19.54) and highest inhibition (80.46) were obtained with 4.40 mg/ml of LEAH. In general, the results indicated that A. hirtum has a damaging effect at high doses; however, a cell safe effect, and a strong antioxidant and DNA protective effect at carefully calculated doses was observed. This provides credibility to justify its general therapeutic activity. Moreover, future studies should identify bioactive molecules and their molecular mechanisms responsible for potential therapies.

Inflammatory effects of hexavalent chromium in the lung: A comprehensive review

Besides smoking, lung cancer can be caused by other factors, including heavy metals such as cadmium, nickel, arsenic, beryllium and hexavalent chromium [Cr(VI)], which is used in multiple settings, resulting in widespread environmental and occupational exposures as well as heavy use. The mechanism by which Cr(VI) causes lung cancer is not completely understood. Currently, it is admitted chromosome instability is a key process in the mechanism of Cr(VI)-induced cancer, and previous studies have suggested Cr(VI) impacts the lung tissue in mice by triggering tissue damage and inflammation. However, the mechanism underlying Cr(VI)-induced inflammation and its exact role in lung cancer are unclear. Therefore, this review aimed to systematically examine previous studies assessing Cr(VI)-induced inflammation and to summarize the major inflammatory pathways involved in Cr(VI)-induced inflammation. In cell culture studies, COX2, VEGF, JAK-STAT, leukotriene B4 (LTB4), MAPK, NF-ҡB and Nrf2 signaling pathways were consistently upregulated by Cr(VI), clearly demonstrating that these pathways are involved in Cr(VI)-induced inflammation. In addition, Akt signaling was also shown to contribute to Cr(VI)-induced inflammation, although discrepant findings were reported. Few mechanistic studies were performed in animal models, in which Cr(VI) upregulated oxidative pathways, NF-kB signaling and the MAPK pathway in the lung tissue. Similar to cell culture studies, opposite effects of Cr(VI) on Akt signaling were reported. This work provides insights into the mechanisms by which Cr(VI) induces lung inflammation. However, discrepant findings and other major issues in study design, both in cell and animal models, suggest that further studies are required to unveil the mechanism of Cr(VI)-induced inflammation and its role in lung cancer.