Ethanolic Extract of Propolis Modulates Autophagy-Related microRNAs in Osteoarthritic Chondrocytes.

Osteoarthritis is a multifactorial joint disease characterized by degeneration, and aging stands as a significant risk factor. Autophagy, a crucial cellular homeostasis mechanism, is influenced by aging and closely linked to cartilage health. This correlation between autophagy, cell death, and OA underscores its relevance in disease progression. MicroRNAs have emerged as autophagy regulators, with miRNA-based interventions showing promise in preclinical models. Remarkably, the ethanolic extract of propolis exhibits positive effects on autophagy-related proteins and healthy cartilage markers in an in vitro osteoarthritis model. The aim of this brief report was to evaluate through in silico analysis and postulate five microRNAs that could regulate autophagy proteins (AKT1, ATG5, and LC3) and assess whether the ethanolic extract of propolis could regulate the expression of these microRNAs. Among the examined miRNAs (miR-19a, miR-125b, miR-181a, miR-185, and miR-335), the ethanolic extract of propolis induced significant changes in four of them. Specifically, miR-125b responded to EEP by counteracting IL-1ß-induced effects, while miR-181a, miR-185, and miR-335 exhibited distinct patterns of expression under EEP treatment. These findings unveil a potential link between miRNAs, EEP, and autophagy modulation in OA, offering promising therapeutic insights. Nevertheless, further validation and clinical translation are warranted to substantiate these promising observations.

Propolis as a Potential Therapeutic Agent to Counteract Age-Related Changes in Cartilage: An In Vivo Study.

Aging is intricately linked to chronic low-grade systemic inflammation, which plays a significant role in various age-related conditions, including osteoarthritis (OA). The aging process significantly influences the development of OA due to alterations in cartilage composition, reduced proteoglycan content, dysregulation of growth factor signaling, and heightened oxidative stress. Propolis, a natural product renowned for its potent antioxidant and anti-inflammatory properties, has the potential to mitigate age-induced changes in cartilage. The primary objective of this study was to rigorously assess the impact of in vivo propolis treatment on the histopathological characteristics of knee articular cartilage in senescent rats. This study involved a cohort of twenty male Sprague-Dawley rats, randomly allocated into four distinct groups for comparative analysis: YR (control group consisting of young rats), SR (senescent rats), SR-EEP (senescent rats treated with an ethanolic extract of propolis, EEP), and SR-V (senescent rats administered with a control vehicle). This study employed comprehensive histological and stereological analyses of knee articular cartilage. Propolis treatment exhibited a significant capacity to alleviate the severity of osteoarthritis, enhance the structural integrity of cartilage, and augment chondrocyte density. These promising findings underscore the potential of propolis as a compelling therapeutic agent to counteract age-related alterations in cartilage and, importantly, to potentially forestall the onset of osteoarthritis.

Relationship between Hypoxic and Immune Pathways Activation in the Progression of Neuroinflammation: Role of HIF-1α and Th17 Cells.

Neuroinflammation is a common event in degenerative diseases of the central and peripheral nervous system, triggered by alterations in the immune system or inflammatory cascade. The pathophysiology of these disorders is multifactorial, whereby the therapy available has low clinical efficacy. This review propounds the relationship between the deregulation of T helper cells and hypoxia, mainly Th17 and HIF-1α molecular pathways, events that are involved in the occurrence of the neuroinflammation. The clinical expression of neuroinflammation is included in prevalent pathologies such as multiple sclerosis, Guillain-Barré syndrome, and Alzheimer's disease, among others. In addition, therapeutic targets are analyzed in relation to the pathways that induced neuroinflammation.

Autophagy and Polyphenols in Osteoarthritis: A Focus on Epigenetic Regulation.

Autophagy is an intracellular mechanism that maintains cellular homeostasis in different tissues. This process declines in cartilage due to aging, which is correlated with osteoarthritis (OA), a multifactorial and degenerative joint disease. Several studies show that microRNAs regulate different steps of autophagy but only a few of them participate in OA. Therefore, epigenetic modifications could represent a therapeutic opportunity during the development of OA. Besides, polyphenols are bioactive components with great potential to counteract diseases, which could reverse altered epigenetic regulation and modify autophagy in cartilage. This review aims to analyze epigenetic mechanisms that are currently associated with autophagy in OA, and to evaluate whether polyphenols are used to reverse the epigenetic alterations generated by aging in the autophagy pathway.

Histological Evaluation and Gene Expression Profiling of Autophagy-Related Genes for Cartilage of Young and Senescent Rats.

Autophagy is a cellular mechanism that protects cells from stress by digesting non-functional cellular components. In the cartilage, chondrocytes depend on autophagy as a principal mechanism to maintain cellular homeostasis. This protective role diminishes prior to the structural damage that normally occurs during aging. Considering that aging is the main risk factor for osteoarthritis, evaluating the expression of genes associated with autophagy in senescent cartilage might allow for the identification of potential therapeutic targets for treatment. Thus, we studied two groups of young and senescent rats. A histological analysis of cartilage and gene expression quantification for autophagy-related genes were performed. In aged cartilage, morphological changes were observed, such as an increase in cartilage degeneration as measured by the modified Mankin score, a decrease in the number of chondrocytes and collagen II (Col2a1), and an increase in matrix metalloproteinase 13 (Mmp13). Moreover, 84 genes associated with autophagy were evaluated by a PCR array analysis, and 15 of them were found to be significantly decreased with aging. Furthermore, an in silico analysis based on by two different bioinformatics software tools revealed that several processes including cellular homeostasis, autophagosome assembly, and aging-as well as several biological pathways such as autophagy, insulin-like growth factor 1 (IGF-1) signaling, PI3K (phosphoinositide 3-kinase)/AKT (serine/threonine kinase) signaling, and mammalian target of rapamycin (mTOR) signaling-were enriched. In conclusion, the analysis identified some potential targets for osteoarthritis treatment that would allow for the development of new therapeutic strategies for this chronic disease.

Propolis Reduces the Expression of Autophagy-Related Proteins in Chondrocytes under Interleukin-1ß Stimulus.

BACKGROUND: Osteoarthritis (OA) is a progressive and multifactorial disease that is associated with aging. A number of changes occur in aged cartilage, such as increased oxidative stress, decreased markers of healthy cartilage, and alterations in the autophagy pathway. Propolis extracts contain a mixture of polyphenols and it has been proved that they have high antioxidant capacity and could regulate the autophagic pathway. Our objective was to evaluate the effect of ethanolic extract of propolis (EEP) on chondrocytes that were stimulated with IL-1ß. METHODS: Rabbit chondrocytes were isolated and stimulated with IL-1ß and treated with EEP. We evaluated cell viability, nitric oxide production, healthy cartilage, and OA markers, and the expression of three proteins associated with the autophagy pathway LC3, ATG5, and AKT1. RESULTS: The EEP treatment reduces the expression of LC3, ATG5, and AKT1, reduces the production of nitric oxide, increases the expression of healthy markers, and reduces OA markers. CONCLUSIONS: These results suggest that treatment with EEP in chondrocytes that were stimulated with IL-1ß has beneficial effects, such as a decrease in the expression of proteins associated with autophagy, MMP13, and production of nitric oxide, and also increased collagen II.

Polyphenol-Related Epigenetic Modifications in Osteoarthritis: Current Therapeutic Perspectives.

The hyaline cartilage is an avascular, aneural and alymphatic tissue with a limited ability to repair itself. When the cartilage is exposed to some kind of injury, it usually triggers osteoarthritis (OA), a prevalent and degenerative joint disease closely related to aging. OA is both complex and multifactorial, and is the most common form of arthritis, being positioned as a major cause of pain and dysfunction in the world. In addition, high OA prevalence can greatly affect work capacity, making this disease a significant social problem, therefore, its prevention and treatment becomes a priority. At this time, there are numerous therapeutic strategies available to improve hyaline cartilage repair by using chondrocytes or mesenchymal cells, but neither is effective enough to generate functional and durable tissue reparation over time. In OA, chondrocytes have an aberrant gene expression and phenotype, resulting in a loss of balance between anabolic and catabolic processes. Environmental influences such as radiation, infection, smoking, nutrients, toxins and stress can affect gene expression patterns, which may constitute risk factors for various chronic and degenerative diseases, such as OA. In addition, considerable evidence shows that epigenetic mechanisms play an important role in OA chondrogenesis and pathogenesis. Natural plant-derived products such as polyphenols, which are secondary metabolites considered to have potential activity to block inflammation in several degenerative diseases, can stimulate epigenetic modifications, and may provide new therapeutic targets and cost-effective treatments. This review aims to present various polyphenolbased therapies currently used for the treatment of several progressive diseases, including OA.

Molecular aspects of breast cancer resistance to drugs (Review).

Despite continuous advances in the knowledge of breast cancer pathophysiology, this type of neoplasia remains a leading cause of cancer-related death in women worldwide. Carcinogenesis takes a progressive course from somatic mutations, alteration of the DNA repair mechanisms, inhibition of growth suppressors, followed by cell proliferation, tissue invasion and risk of metastasis. Less than 10% of all cancers are hereditary, and in the case of breast cancer only 8%, a phenomenon linked to genetic changes in BRCA1 or BRCA2. All the other cancers can be caused by an infection (15%) or in most cases (75%) the etiology is unknown. Patients with genetic mutations in BRCA1 or BRCA2 have 30-60% likelihood of developing a second primary breast cancer and between 11 and 45% risk of ovarian cancer, HER-2/neu is overexpressed in ~30% of human breast tumors and it has a predictive role in chemotherapy and endocrine therapy.

Omega 3 chronic supplementation attenuates myocardial ischaemia-reperfusion injury through reinforcement of antioxidant defense system in rats.

Currently, controversial clinical data about the protective effects in the consumption of n-3 polyunsaturated fatty acids (PUFAs) in ischaemic heart diseases exist. Improved myocardial resistance to ischaemia-reperfusion (IR) injury results in non-lethal myocardial infarction, which is a relevant factor in the myocardial function. We hypothesized that chronic supplementation with PUFAs reduced infarct size (IS) and induced an improvement on oxidative stress-related parameters in IR model. Rats were supplemented with two doses of PUFAs D1 (n = 7) (0.6 g kg(-1) d(-1) ) and D2 (n = 7) (1.2 g kg(-1) d(-1) ) for 8 weeks. Control group (n = 7) received only standard diet. In ex vivo model, all rat hearts were subjected to 30 min of global ischaemia followed by 120 min of reperfusion. The IS and left ventricular function were assessed. Lipid peroxidation, reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio and antioxidant enzyme activity were measured in the whole heart. The results show a reduction in IS in a dose-dependent manner with PUFAs D1 (30.6%) and D2 (48.5%) and higher values of left ventricular developed pressure, at the end of the reperfusion, for each dose, respectively (p < 0.05). The two PUFAs groups showed higher values of GSH/GSSG ratio and lipid peroxidation, and higher values of activity of antioxidant enzymes catalase, superoxide dismutase and glutathione peroxidase at basal condition (p < 0.05). At the end of reperfusion, the GSH/GSSG ratio and antioxidants enzyme activity did not show a significant drop in their values (p > 0.05). These findings suggested that the supplementation with PUFAs induces cardioprotection against IR injury, associated with reinforcement of the antioxidant defense system.