Anti-Atherosclerotic Effect of Gossypetin on Abnormal Vascular Smooth Muscle Cell Proliferation and Migration

Role of oxidative stress in the concurrent development of osteoporosis and tendinopathy: Emerging challenges and prospects for treatment modalities

Both osteoporosis and tendinopathy are widely prevalent disorders, encountered in diverse medical contexts. Whilst each condition has distinct pathophysiological characteristics, they share several risk factors and underlying causes. Notably, oxidative stress emerges as a crucial intersecting factor, playing a pivotal role in the onset and progression of both diseases. This imbalance arises from a dysregulation in generating and neutralising reactive oxygen species (ROS), leading to an abnormal oxidative environment. Elevated levels of ROS can induce multiple cellular disruptions, such as cytotoxicity, apoptosis activation and reduced cell function, contributing to tissue deterioration and weakening the structural integrity of bones and tendons. Antioxidants are substances that can prevent or slow down the oxidation process, including Vitamin C, melatonin, resveratrol, anthocyanins and so on, demonstrating potential in treating these overlapping disorders. This comprehensive review aims to elucidate the complex role of oxidative stress within the interlinked pathways of these comorbid conditions. By integrating contemporary research and empirical findings, our objective is to outline new conceptual models and innovative treatment strategies for effectively managing these prevalent diseases. This review underscores the importance of further in-depth research to validate the efficacy of antioxidants and traditional Chinese medicine in treatment plans, as well as to explore targeted interventions focused on oxidative stress as promising areas for future medical advancements.

Flavonoid gossypetin protects alveolar bone and limits inflammation in ligature-induced periodontitis in mice

BACKGROUND

Bacterial-induced inflammation instigates the destruction of hard and soft tissues surrounding teeth in periodontitis. In severe cases, the increased number and activity of osteoclasts induces the resorption of alveolar bones, ultimately leading to tooth loss. Because of their diverse chemical structures and bioactivities, natural compounds are often suggested to treat a wide variety of diseases, including inflammatory disorders.

METHODS

In the present study, we demonstrated an inhibitory effect of gossypetin, a hexahydroxy flavone, on osteoclast differentiation and bone resorption using in vitro culture of osteoclasts from mouse bone marrow macrophage (BMM) precursors and in vivo model of ligature-induced periodontitis in mice.

RESULTS

Gossypetin significantly reduced the differentiation of osteoclasts from mouse BMM precursors in the presence of the receptor activator of nuclear factor κB ligand (RANKL). In vitro, gossypetin inhibited critical signaling events downstream of RANKL including the auto-amplification of nuclear factor of activated T-cells, cytoplasmic 1, Ca2+ oscillations, and the generation of reactive oxygen species. In a mouse ligature-induced periodontitis model, the administration of gossypetin significantly reduced osteoclastogenesis and alveolar bone resorption. Furthermore, gossypetin prevented the ligature-induced increase in macrophages and T cells and reduced the production of tumor necrosis factor-α and interleukin-6.

CONCLUSION

Taken together, these results show anti-osteoclastogenic and anti-inflammatory effects of gossypetin, suggesting the potential use of this natural compound in periodontitis.

Role of bio-flavonols and their derivatives in improving mitochondrial dysfunctions associated with pancreatic tumorigenesis

Mitochondria, a cellular metabolic center, efficiently fulfill cellular energy needs and regulate crucial metabolic processes, including cellular proliferation, differentiation, apoptosis, and generation of reactive oxygen species. Alteration in the mitochondrial functions leads to metabolic imbalances and altered extracellular matrix dynamics in the host, utilized by solid tumors like pancreatic cancer (PC) to get energy benefits for fast-growing cancer cells. PC is highly heterogeneous and remains unidentified for a longer time because of its complex pathophysiology, retroperitoneal position, and lack of efficient diagnostic approaches, which is the foremost reason for accounting for the seventh leading cause of cancer-related deaths worldwide. PC cells often respond poorly to current therapeutics because of dense stromal barriers in the pancreatic tumor microenvironment, which limit the drug delivery and distribution of antitumor immune cell populations. As an alternative approach, various natural compounds like flavonoids are reported to possess potent antioxidant and anticancerous properties and are less toxic than current chemotherapeutic drugs. Therefore, we aim to summarize the current state of knowledge regarding the pharmacological properties of flavonols in PC in this review from the perspective of mitigating mitochondrial dysfunctions associated with cancer cells. Our literature survey indicates that flavonols efficiently regulate cellular metabolism by scavenging reactive oxygen species, mitigating inflammation, and arresting the cell cycle to promote apoptosis in tumor cells via intrinsic mitochondrial pathways. In particular, flavonols proficiently inhibit the cancer-associated proliferation and inflammatory pathways such as EGFR/MAPK, PI3K/Akt, and nuclear factor κB in PC. Overall, this review provides in-depth evidence about the therapeutic potential of flavonols for future anticancer strategies against PC; still, more multidisciplinary human interventional studies are required to dissect their pharmacological effect accurately.

The Potential Role of Gossypetin in the Treatment of Diabetes Mellitus and Its Associated Complications: A Review

Type 2 diabetes mellitus (T2DM) is a metabolic disorder caused by insulin resistance and dysfunctional beta (β)-cells in the pancreas. Hyperglycaemia is a characteristic of uncontrolled diabetes which eventually leads to fatal organ system damage. In T2DM, free radicals are continuously produced, causing extensive tissue damage and subsequent macro-and microvascular complications. The standard approach to managing T2DM is pharmacological treatment with anti-diabetic medications. However, patients' adherence to treatment is frequently decreased by the side effects and expense of medications, which has a detrimental impact on their health outcomes. Quercetin, a flavonoid, is a one of the most potent anti-oxidants which ameliorates T2DM. Thus, there is an increased demand to investigate quercetin and its derivatives, as it is hypothesised that similar structured compounds may exhibit similar biological activity. Gossypetin is a hexahydroxylated flavonoid found in the calyx of Hibiscus sabdariffa. Gossypetin has a similar chemical structure to quercetin with an extra hydroxyl group. Furthermore, previous literature has elucidated that gossypetin exhibits neuroprotective, hepatoprotective, reproprotective and nephroprotective properties. The mechanisms underlying gossypetin's therapeutic potential have been linked to its anti-oxidant, anti-inflammatory and immunomodulatory properties. Hence, this review highlights the potential role of gossypetin in the treatment of diabetes and its associated complications.

Gossypetin Prevents the Progression of Nonalcoholic Steatohepatitis by Regulating Oxidative Stress and AMP-Activated Protein Kinase

Nonalcoholic steatohepatitis (NASH) is a severe liver metabolic disorder, however, there are still no effective and safe drugs for its treatment. Previous clinical trials used various therapeutic approaches to target individual pathologic mechanisms, but these approaches were unsuccessful because of the complex pathologic causes of NASH. Combinatory therapy in which two or more drugs are administered simultaneously to patients with NASH, however, carries the risk of side effects associated with each individual drug. To solve this problem, we identified gossypetin as an effective dual-targeting agent that activates AMP-activated protein kinase (AMPK) and decreases oxidative stress. Administration of gossypetin decreased hepatic steatosis, lobular inflammation and liver fibrosis in the liver tissue of mice with choline-deficient high-fat diet and methionine-choline deficient diet (MCD) diet-induced NASH. Gossypetin functioned directly as an antioxidant agent, decreasing hydrogen peroxide and palmitate-induced oxidative stress in the AML12 cells and liver tissue of MCD diet-fed mice without regulating the antioxidant response factors. In addition, gossypetin acted as a novel AMPK activator by binding to the allosteric drug and metabolite site, which stabilizes the activated structure of AMPK. Our findings demonstrate that gossypetin has the potential to serve as a novel therapeutic agent for nonalcoholic fatty liver disease /NASH. SIGNIFICANCE STATEMENT: This study demonstrates that gossypetin has preventive effect to progression of nonalcoholic steatohepatitis (NASH) as a novel AMP-activated protein kinase (AMPK) activator and antioxidants. Our findings indicate that simultaneous activation of AMPK and oxidative stress using gossypetin has the potential to serve as a novel therapeutic approach for nonalcoholic fatty liver disease /NASH patients.

Therapeutic effect of gossypetin against paraquat-induced testicular damage in male rats: a histological and biochemical study

Paraquat (PQ) is an organic compound, which is commonly used as a herbicide in the agriculture sector, and it is also known to stimulate critical damages in the male reproductive system. Gossypetin (GPTN) is one of important members of the flavonoid family, which is an essential compound in flowers and calyx of Hibiscus sabdariffa with potential pharmacological properties. The current investigation was aimed to examine the ameliorative potential of GPTN against PQ-instigated testicular damages. Adult male Sprague-Dawley rats (n = 48) were distributed into four groups: control, PQ (5 mg/kg), PQ + GPTN (5 mg/kg + 30 mg/kg respectively), and GPTN (30 mg/kg). After 56 days of treatment, biochemical, spermatogenic indices, hormonal, steroidogenic, pro-or-anti-apoptotic, and histopathological parameters were estimated. PQ exposure disturbed the biochemical profile by reducing the activities of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione reductase (GSR), while it increased the concentration of reactive oxygen species (ROS) and malondialdehyde (MDA) level. Furthermore, PQ exposure decreased the sperm motility, viability, number of hypo-osmotic tail swelled spermatozoa, and epididymal sperm count; additionally, it increased sperm morphological (head mid-piece and tail) abnormalities. Moreover, PQ lessened the follicle-stimulating hormone (FSH), luteinizing hormone (LH), and plasma testosterone levels. Besides, PQ-intoxication downregulated the gene expression of steroidogenic enzymes (StAR, 3β-HSD, and 17β-HSD) and anti-apoptotic marker (Bcl-2), whereas upregulated the gene expression of apoptotic markers (Bax and Caspase-3). PQ exposure led to histopathological damages in testicular tissues as well. Nonetheless, GPTN inverted all the illustrated impairments in testes. Taken together, GPTN could potently ameliorate PQ-induced reproductive dysfunctions due to its antioxidant, androgenic, and anti-apoptotic potential.

Inhibiting vascular smooth muscle cell proliferation mediated by osteopontin via regulating gut microbial lipopolysaccharide: A novel mechanism for paeonol in atherosclerosis treatment

Background: Although the gut microbiota is involved in metabolic disease such as atherosclerosis, the underlying mechanism remains elusive. Paeonol (Pae) is a natural phenolic compound isolated from Cortex Moutan, which exhibits anti-atherosclerotic effects. Our previous research demonstrated gut microbiota as a site of Pae action. However, the mechanism by which Pae exerts its anti-atherosclerotic effect by the regulation of gut microbiota remains unclear.

Objective: To investigate a potential mechanistic link between the gut microbial lipopolysaccharide (LPS) and vascular smooth muscle cell (VSMC) proliferation in atherosclerosis progression and explore the possible role of Pae.

Methods: Experimental atherosclerosis was established in ApoE^−/− mice, and the atherosclerosis mice were treated with Pae for 4 weeks before being sacrificed for analyses while conducting fecal microbiota transplantation (FMT). The plaque area, levels of serum LPS, expressions of inflammatory factors in serum or aorta, and intestinal barrier permeability were determined. VSMCs were co-cultured with THP-1 cells. CCK-8 assay and EdU staining were performed to assess the proliferative capacity of VSMCs. Immunofluorescence staining was performed to observe the nuclear transfer of p65. Western blotting was used to detect the candidate protein expression level, and quantitative real-time PCR (qRT-PCR) was used to detect the mRNA expression level in tissues or cells of each group.

Results: During atherosclerosis progression, gut dysbiosis leads to the peripheral accumulation of gut microbial LPS, which acts as a trigger to stimulate osteopontin (OPN) production from circulating monocytes, inducing cell-to-cell crosstalk to promote VSMC proliferation in the aorta. Importantly, the elevation of LPS and OPN concentrations in the blood was also observed in patients with atherosclerosis. Pae could significantly improve atherosclerosis, suppress gut microbial LPS accumulation, and inhibit monocyte/macrophage activation and VSMC proliferation.

Conclusions: The present study provides a mechanistic scenario for how long-term stimulation of gut microbial LPS in circulating blood generates a pathological secondary response that leads to abnormal proliferation of VSMCs using high OPN expression in circulating monocytes and suggests a novel strategy for atherosclerosis therapy by remodeling the gut microbiota.

New Insight in HDACs: Potential Therapeutic Targets for the Treatment of Atherosclerosis

Atherosclerosis (AS) features include progressive hardening and reduced elasticity of arteries. AS is the leading cause of morbidity and mortality. An increasing amount of evidence showed that epigenetic modifications on genes serve are a main cause of several diseases, including AS. Histone deacetylases (HDACs) promote the deacetylation at lysine residues, thereby condensing the chromatin structures and further inhibiting the transcription of downstream genes. HDACs widely affect various physiological and pathological processes through transcriptional regulation or deacetylation of other non-histone proteins. In recent years, the role of HDACs in vascular systems has been revealed, and their effects on atherosclerosis have been widely reported. In this review, we discuss the members of HDACs in vascular systems, determine the diverse roles of HDACs in AS, and reveal the effects of HDAC inhibitors on AS progression. We provide new insights into the potential of HDAC inhibitors as drugs for AS treatment.

Ginsenoside Rh1 Inhibits Angiotensin II-Induced Vascular Smooth Muscle Cell Migration and Proliferation through Suppression of the ROS-Mediated ERK1/2/p90RSK/KLF4 Signaling Pathway

Vascular smooth muscle cell (VSMC) proliferation and migration play key roles in the progression of atherosclerosis and restenosis. A variety of ginsenosides exert various cardiovascular benefits. However, whether and how ginsenoside Rh1 (Rh1) inhibits VSMC dysfunction remain unclear. Here, we investigated the inhibitory effects of Rh1 on rat aortic smooth muscle cell (RASMC) migration and proliferation induced by angiotensin II (Ang II) and the underlying mechanisms. Cell proliferation and migration were evaluated using sulforhodamine B and wound-healing assay. The molecular mechanisms were investigated using Western blotting, quantitative reverse-transcription polymerase chain reaction analysis, immunofluorescence staining, and luciferase assay. Reactive oxygen species (ROS) production was measured using dihydroethidium and MitoSOX staining. We found that Rh1 dose-dependently suppressed Ang II-induced cell proliferation and migration. Concomitantly, Ang II increased protein levels of osteopontin, vimentin, MMP2, MMP9, PCNA, and cyclin D1, while these were reduced by Rh1 pretreatment. Notably, Ang II enhanced both the protein expression and promoter activity of KLF4, a key regulator of phenotypic switching, whereas pretreatment with Rh1 reversed these effects. Mechanistically, the effects of Rh1 on VSMC proliferation and migration were found to be associated with inhibition of ERK1/2/p90RSK signaling. Furthermore, the inhibitory effects of Rh1 were accompanied by inhibition of ROS production. In conclusion, Rh1 inhibited the Ang II-induced migration and proliferation of RASMCs by suppressing the ROS-mediated ERK1/2/p90RSK signaling pathway.

Redox Systems, Oxidative Stress, and Antioxidant Defences in Health and Disease

Reactive oxygen and nitrogen species (RONS) play a key role in the regulation of cell survival [...].

Anti-Oxidative, Anti-Inflammatory and Anti-Apoptotic Effects of Flavonols: Targeting Nrf2, NF-κB and p53 Pathways in Neurodegeneration

Neurodegenerative diseases are one of the leading causes of disability and death worldwide. Intracellular transduction pathways that end in the activation of specific transcription factors are highly implicated in the onset and progression of pathological changes related to neurodegeneration, of which those related to oxidative stress (OS) and neuroinflammation are particularly important. Here, we provide a brief overview of the key concepts related to OS- and neuroinflammation-mediated neuropathological changes in neurodegeneration, together with the role of transcription factors nuclear factor erythroid 2-related factor 2 (Nrf2) and nuclear factor-κB (NF-κB). This review is focused on the transcription factor p53 that coordinates the cellular response to diverse genotoxic stimuli, determining neuronal death or survival. As current pharmacological options in the treatment of neurodegenerative disease are only symptomatic, many research efforts are aimed at uncovering efficient disease-modifying agents. Natural polyphenolic compounds demonstrate powerful anti-oxidative, anti-inflammatory and anti-apoptotic effects, partially acting as modulators of signaling pathways. Herein, we review the current understanding of the therapeutic potential and limitations of flavonols in neuroprotection, with emphasis on their anti-oxidative, anti-inflammatory and anti-apoptotic effects along the Nrf2, NF-κB and p53 pathways. A better understanding of cellular and molecular mechanisms of their action may pave the way toward new treatments.