Influence of 10-(6-plastoquinonyl) decyltriphenylphosphonium on free-radical homeostasis in the heart and blood serum of rats with streptozotocin-induced hyperglycemia

10-(6-Plastoquinonyl) decyltriphenylphosphonium imparts anti-colitogenic protection through recovery of mitochondrial dysfunction in ulcerated murine colon: Implications in ulcerative colitis

AIMS

To elucidate the impact of 10-(6-plastoquinonyl) decyltriphenylphosphonium (SkQ1) as an anti-colitogenic agent for maintenance of colon epithelial tract in ulcerated mice through recovery of mitochondrial dysfunction and mitochondrial stress by virtue of its free radical scavenging properties.

MAIN METHODS

DSS induced ulcerated BALB/c mice were treated with SkQ1 for 14 days @ 30 nmol/kg/body wt./day/mice. Post-treatment, isolated colonic mitochondria were utilized for spectrophotometric and spectrofluorometric biochemical analysis of various mitochondrial functional variables including individual mitochondrial respiratory enzyme complexes. Confocal microscopy was utilized for measuring mitochondrial membrane potential in vivo. ELISA technique was adapted for measuring colonic nitrite and 3-nitrotyrosine (3-NT) content. Finally in vitro cell line study was carried out to substantiate in vivo findings and elucidate the involvement of free radicals in UC using antioxidant/free radical scavenging regimen.

KEY FINDINGS

Treatment with SkQ1 in vivo reduced histopathological severity of colitis, induced recovery of mitochondrial respiratory complex activities and associated functional variables, improved oxidative stress indices and normalized mitochondrial cardiolipin content. Importantly, SkQ1 lowered nitrite concentration and 3-nitrotyrosine formation in vivo. In vitro SkQ1 restored mitochondrial functions wherein the efficacy of SkQ1 proved equal or better compared to SOD and DMSO indicating predominant involvement of O2- and OH in UC. However, NO and ONOO- also seemed to play a secondary role as MEG and L-NAME provided lesser protection as compared to SOD and DMSO.

SIGNIFICANCE

SkQ1 can be considered as a potent anti-colitogenic agent by virtue of its free radical scavenging properties in treating UC.

Clinical Relevance of lncRNA and Mitochondrial Targeted Antioxidants as Therapeutic Options in Regulating Oxidative Stress and Mitochondrial Function in Vascular Complications of Diabetes

Metabolic imbalances and persistent hyperglycemia are widely recognized as driving forces for augmented cytosolic and mitochondrial reactive oxygen species (ROS) in diabetes mellitus (DM), fostering the development of vascular complications such as diabetic nephropathy, diabetic cardiomyopathy, diabetic neuropathy, and diabetic retinopathy. Therefore, specific therapeutic approaches capable of modulating oxidative milieu may provide a preventative and/or therapeutic benefit against the development of cardiovascular complications in diabetes patients. Recent studies have demonstrated epigenetic alterations in circulating and tissue-specific long non-coding RNA (lncRNA) signatures in vascular complications of DM regulating mitochondrial function under oxidative stress. Intriguingly, over the past decade mitochondria-targeted antioxidants (MTAs) have emerged as a promising therapeutic option for managing oxidative stress-induced diseases. Here, we review the present status of lncRNA as a diagnostic biomarker and potential regulator of oxidative stress in vascular complications of DM. We also discuss the recent advances in using MTAs in different animal models and clinical trials. We summarize the prospects and challenges for the use of MTAs in treating vascular diseases and their application in translation medicine, which may be beneficial in MTA drug design development, and their application in translational medicine.

In Vivo and Ex Vivo Evaluation of 1,3-Thiazolidine-2,4-Dione Derivatives as Euglycemic Agents

Thiazolidinediones (TZDs), used to treat type 2 diabetes mellitus, act as full agonists of the peroxisome proliferator-activated receptor gamma. Unfortunately, they produce adverse effects, including weight gain, hepatic toxicity, and heart failure. Our group previously reported the design, synthesis, in silico evaluation, and acute oral toxicity test of two TZD derivatives, compounds 40 (C40) and 81 (C81), characterized as category 5 and 4, respectively, under the Globally Harmonized System. The aim of this study was to determine whether C40, C81, and a new compound, C4, act as euglycemic and antioxidant agents in male Wistar rats with streptozotocin-induced diabetes. The animals were randomly divided into six groups (n = 7): the control, those with diabetes and untreated, and those with diabetes and treated with pioglitazone, C40, C81, or C4 (daily for 21 days). At the end of the experiment, tissue samples were collected to quantify the level of glucose, insulin, triglycerides, total cholesterol, and liver enzymes, as well as enzymatic and nonenzymatic antioxidant activity. C4, without a hypoglycemic effect, displayed the best antioxidant activity. Whereas C81 could only attenuate the elevated level of blood glucose, C40 generated euglycemia by the end of the treatment. All compounds produced a significant decrease in triglycerides.

Mitochondrial Antioxidant SkQ1 Has a Beneficial Effect in Experimental Diabetes as Based on the Analysis of Expression of microRNAs and mRNAs for the Oxidative Metabolism Regulators

Diabetes mellitus and related complications are among the most important problems of the world-leading healthcare systems. Despite their priority, molecular and genetic aspects of diabetes pathogenesis are poorly understood; however, the involvement of oxidative stress in this process is undoubted. Rats with experimental diabetes induced by the intraperitoneal injection of alloxan were subjected to the antioxidant pre-therapy with a series of mitochondria-targeted 10-(6’-plastoquinonyl)decyltriphenylphosphonium (SkQ1) injections and analyzed for the expression of mRNAs and microRNAs by real-time quantitative polymerase chain reaction to identify potential predictors of diabetes. Animals that received SkQ1 before diabetes induction demonstrated lower blood glucose levels compared to the diabetic animals not subjected to the therapy. SkQ1 caused changes in the mRNA levels of genes involved in the cellular defense against free radicals, which indicates a beneficial effect of the pre-therapy. Moreover, similar changes were observed on the epigenetic level, as the microRNA expression patterns not only proved the SkQ1 efficacy but also correlated with the expression levels of their mRNA targets. Oxidative stress and macromolecule damage by free radicals are determining factors in diabetes, which suggests that strategies aimed at restoring the antioxidant status of the cell can be beneficial. Mitochondria-targeted antioxidant SkQ1 demonstrates positive effects on several levels, from the normalization of the blood glucose content to genetic and epigenetic changes. Our results can serve as a basis for the development of novel therapeutic and diagnostic strategies.

Natural and synthetic antioxidants targeting cardiac oxidative stress and redox signaling in cardiometabolic diseases

Cardiometabolic diseases (CMDs) are metabolic diseases (e.g., obesity, diabetes, atherosclerosis, rare genetic metabolic diseases, etc.) associated with cardiac pathologies. Pathophysiology of most CMDs involves increased production of reactive oxygen species and impaired antioxidant defense systems, resulting in cardiac oxidative stress (OxS). To alleviate OxS, various antioxidants have been investigated in several diseases with conflicting results. Here we review the effect of CMDs on cardiac redox homeostasis, the role of OxS in cardiac pathologies, as well as experimental and clinical data on the therapeutic potential of natural antioxidants (including resveratrol, quercetin, curcumin, vitamins A, C, and E, coenzyme Q10, etc.), synthetic antioxidants (including N-acetylcysteine, SOD mimetics, mitoTEMPO, SkQ1, etc.), and promoters of antioxidant enzymes in CMDs. As no antioxidant indicated for the prevention and/or treatment of CMDs has reached the market despite the large number of preclinical and clinical studies, a sizeable translational gap is evident in this field. Thus, we also highlight potential underlying factors that may contribute to the failure of translation of antioxidant therapies in CMDs.

Mitochondria-Targeted Drug Delivery in Cardiovascular Disease: A Long Road to Nano-Cardio Medicine

Cardiovascular disease (CVD) represents a major threat for human health. The available preventive and treatment interventions are insufficient to revert the underlying pathological processes, which underscores the urgency of alternative approaches. Mitochondria dysfunction plays a key role in the etiopathogenesis of CVD and is regarded as an intriguing target for the development of innovative therapies. Oxidative stress, mitochondrial permeability transition pore opening, and excessive fission are major noxious pathways amenable to drug therapy. Thanks to the advancements of nanotechnology research, several mitochondria-targeted drug delivery systems (DDS) have been optimized with improved pharmacokinetic and biocompatibility, and lower toxicity and antigenicity for application in the cardiovascular field. This review summarizes the recent progress and remaining obstacles in targeting mitochondria as a novel therapeutic option for CVD. The advantages of nanoparticle delivery over un-targeted strategies are also discussed.