Oral delivery of nanoparticle urolithin A normalizes cellular stress and improves survival in mouse model of cisplatin-induced AKI

MiRNA-192-5p-targeted activated leukocyte cell adhesion molecule improved inflammatory injury of neonatal necrotizing enterocolitis

BACKGROUND

Neonatal necrotizing enterocolitis (NEC) is a common gastrointestinal emergency in neonates. MiRNA-192-5p was found associated with ulcerative colitis (UC) progression, also with aberrant expression in intestinal cancer tissue. However, the effects of miRNA-192-5p on NEC have not been reported.

METHODS

Based on the bioinformatics analysis of the GEO dataset, miR-192-5p was identified as the differentially expressed miRNA in NEC, and activated leukocyte cell adhesion molecule (ALCAM) was predicted as its target. After that, in vitro, rat intestinal epithelial cell-6 (IEC-6) were stimulated with LPS to construct a cell model of NEC. IEC-6 cells were transfected with miRNA-192-5p mimics, miRNA-192-5p inhibitors, or miRNA-192-5p inhibitors + sh-ALCAM, and relevant negative control. In vivo, SD rats were treated with artificial feeding, hypoxic reoxygenation, cold stimulation, and LPS gavage to induce NEC, followed by injection of agomiR-NC or agomiRNA-192-5p. Then effects of miRNA-192-5p on NEC model IEC-6 cell viability, apoptosis, ALCAM expression, Interleukin (IL)-1β and IL-6 levels, intestinal injury, intestinal permeability were detected.

RESULTS

MiRNA-192-5p expression was downregulated in NEC IEC-6 cells, whose overexpression increased IEC-6 cell viability. MiRNA-192-5p inhibitors increased IL-1β, IL-6 levels and promoted IEC-6 cell apoptosis. MiRNA-192-5p targeting of ALCAM decreased ALCAM expression, IL-1β, and IL-6 levels. AgomiRNA-192-5p decreased ALCAM, IL-1β, and IL-6 levels in intestinal tissue and pathological damage and increased miRNA-192-5p levels.

CONCLUSION

MiR-192-5p protects against intestinal injury by inhibiting ALCAM-mediated inflammation and intestinal epithelial cells, which would provide a new idea for NEC treatment.

Gut microbiota-generated metabolites: missing puzzles to hosts' health, diseases, and aging

The gut microbiota, an intricate community of bacteria residing in the gastrointestinal system, assumes a pivotal role in various physiological processes. Beyond its function in food breakdown and nutrient absorption, gut microbiota exerts a profound influence on immune and metabolic modulation by producing diverse gut microbiota-generated metabolites (GMGMs). These small molecules hold potential to impact host health via multiple pathways, which exhibit remarkable diversity, and have gained increasing attention in recent studies. Here, we elucidate the intricate implications and significant impacts of four specific metabolites, Urolithin A (UA), equol, Trimethylamine N-oxide (TMAO), and imidazole propionate, in shaping human health. Meanwhile, we also look into the advanced research on GMGMs, which demonstrate promising curative effects and hold great potential for further clinical therapies. Notably, the emergence of positive outcomes from clinical trials involving GMGMs, typified by UA, emphasizes their promising prospects in the pursuit of improved health and longevity. Collectively, the multifaceted impacts of GMGMs present intriguing avenues for future research and therapeutic interventions. [BMB Reports 2024; 57(5): 207-215].

Recent Advances in Nanomaterials for the Treatment of Acute Kidney Injury

Acute kidney injury (AKI) is a serious clinical syndrome with high morbidity, elevated mortality, and poor prognosis, commonly considered a "sword of Damocles" for hospitalized patients, especially those in intensive care units. Oxidative stress, inflammation, and apoptosis, caused by the excessive production of reactive oxygen species (ROS), play a key role in AKI progression. Hence, the investigation of effective and safe antioxidants and inflammatory regulators to scavenge overexpressed ROS and regulate excessive inflammation has become a promising therapeutic option. However, the unique physiological structure and complex pathological alterations in the kidneys render traditional therapies ineffective, impeding the residence and efficacy of most antioxidant and anti-inflammatory small molecule drugs within the renal milieu. Recently, nanotherapeutic interventions have emerged as a promising and prospective strategy for AKI, overcoming traditional treatment dilemmas through alterations in size, shape, charge, and surface modifications. This Review succinctly summarizes the latest advancements in nanotherapeutic approaches for AKI, encompassing nanozymes, ROS scavenger nanomaterials, MSC-EVs, and nanomaterials loaded with antioxidants and inflammatory regulator. Following this, strategies aimed at enhancing biocompatibility and kidney targeting are introduced. Furthermore, a brief discussion on the current challenges and future prospects in this research field is presented, providing a comprehensive overview of the evolving landscape of nanotherapeutic interventions for AKI.

Liposomes encapsulation by pH driven improves the stability, bioaccessibility and bioavailability of urolithin A: A comparative study

Urolithin A (UroA) is gut metabolites of ellagitannins possessing a vast range of biological activities, but its poor water solubility and low bioavailability hinder its potential applications. This study utilized the pH dependent dissolution characteristics of UroA and employed a simple pH-driven method to load UroA into liposomes. The characterization and stability of obtained liposomes under different conditions were evaluated, and their oral bioavailability was tested by pharmacokinetics, and compared with UroA liposomes prepared using traditional thin film dispersion (TFM-ULs). Results indicated that liposomes could effectively encapsulate UroA. The UroA liposomes prepared by the pH-driven method (PDM-ULs) showed lower particle size, polydispersity index, zeta potential, and higher encapsulation efficiency than TFM-ULs. Interestingly, better thermal stability, storage stability, in vitro digestion stability, and higher bioaccessibility were also found on PDM-ULs. Moreover, pharmacokinetic experiments in rats demonstrated that PDM-ULs could significantly improve the bioavailability of UroA, with an absorption efficiency 1.91 times that of TFM-ULs. Therefore, our findings suggest that liposomes prepared by pH-driven methods have great potential in improving the stability and bioavailability of UroA.

Urolithin A in Health and Diseases: Prospects for Parkinson's Disease Management

Parkinson's disease (PD) is a chronic and progressive neurodegenerative disorder characterized by a complex pathophysiology and a range of symptoms. The prevalence increases with age, putting the ageing population at risk. Disease management includes the improvement of symptoms, the comfort of the patient's life, and palliative care. As there is currently no cure, growing evidence points towards the beneficial role of polyphenols on neurodegeneration. Numerous studies indicate the health benefits of the family of urolithins, especially urolithin A (UA). UA is a bacterial metabolite produced by dietary ellagitannins and ellagic acid. An expanding body of literature explores the involvement of the compound in mitochondrial health, and its anti-inflammatory, anti-oxidant, and anti-apoptotic properties. The review organizes the existing knowledge on the role of UA in health and diseases, emphasizing neurodegenerative diseases, especially PD. We gathered data on the potential neuroprotective effect in in vivo and in vitro models. We discussed the possible mechanisms of action of the compound and related health benefits to give a broader perspective of potential applications of UA in neuroprotective strategies. Moreover, we projected the future directions of applying UA in PD management.

Small non-coding RNAs encoded by RNA viruses: old controversies and new lessons from the COVID-19 pandemic

The recurring outbreaks caused by emerging RNA viruses have fostered an increased interest in the research of the mechanisms that regulate viral life cycles and the pathological outcomes associated with infections. Although interactions at the protein level are well-studied, interactions mediated by RNA molecules are less explored. RNA viruses can encode small non-coding RNAs molecules (sncRNAs), including viral miRNAs (v-miRNAs), that play important roles in modulating host immune responses and viral replication by targeting viral or host transcripts. Starting from the analysis of public databases compiling the known repertoire of viral ncRNA molecules and the evolution of publications and research interests on this topic in the wake of the COVID-19 pandemic, we provide an updated view on the current knowledge on viral sncRNAs, with a focus on v-miRNAs encoded by RNA viruses, and their mechanisms of action. We also discuss the potential of these molecules as diagnostic and prognostic biomarkers for viral infections and the development of antiviral therapies targeting v-miRNAs. This review emphasizes the importance of continued research efforts to characterize sncRNAs encoded by RNA viruses, identifies the most relevant pitfalls in the study of these molecules, and highlights the paradigm changes that have occurred in the last few years regarding their biogenesis, prevalence and functional relevance in the context of host-pathogen interactions.

Mitochondrial quality control in acute kidney disease

Acute kidney disease (AKD) involves multiple pathogenic mechanisms,  including maladaptive repair of renal cells that are rich in mitochondria. Maintenance of mitochondrial homeostasis and quality control is crucial for normal kidney function. Mitochondrial quality control serves to maintain mitochondrial function under various conditions, including mitochondrial bioenergetics, mitochondrial biogenesis, mitochondrial dynamics (fusion and fission) and mitophagy. To date, increasing evidence indicates that mitochondrial quality control is disrupted when acute kidney disease develops. This review describes the mechanisms of mitochondria quality control in acute kidney disease, aiming to provide clues to help design new clinical treatments.

The Mitochondrion: A Promising Target for Kidney Disease

Mitochondrial dysfunction is important in the pathogenesis of various kidney diseases and the mitochondria potentially serve as therapeutic targets necessitating further investigation. Alterations in mitochondrial biogenesis, imbalance between fusion and fission processes leading to mitochondrial fragmentation, oxidative stress, release of cytochrome c and mitochondrial DNA resulting in apoptosis, mitophagy, and defects in energy metabolism are the key pathophysiological mechanisms underlying the role of mitochondrial dysfunction in kidney diseases. Currently, various strategies target the mitochondria to improve kidney function and kidney treatment. The agents used in these strategies can be classified as biogenesis activators, fission inhibitors, antioxidants, mPTP inhibitors, and agents which enhance mitophagy and cardiolipin-protective drugs. Several glucose-lowering drugs, such as glucagon-like peptide-1 receptor agonists (GLP-1-RA) and sodium glucose co-transporter-2 (SGLT-2) inhibitors are also known to have influences on these mechanisms. In this review, we delineate the role of mitochondrial dysfunction in kidney disease, the current mitochondria-targeting treatment options affecting the kidneys and the future role of mitochondria in kidney pathology.

Ameliorative impacts of polymeric and metallic nanoparticles on cisplatin-induced nephrotoxicity: a 2011-2022 review

Cisplatin (CDDP) is a well-known platinum-based drug used in the treatment of various malignancies. However, the widespread side effects that this drug leaves on normal tissues make its use limited. Since cisplatin is mainly eliminated from the kidneys, CDDP-induced nephrotoxicity is the most significant dose-limiting complication attributed to cisplatin, which often leads to dose withdrawal. Considering the high efficiency of cisplatin in chemotherapy, finding renoprotective drug delivery systems for this drug is a necessity. In this regard, we can take advantages of different nanoparticle-based approaches to deliver cisplatin into tumors either using passive targeting or using specific receptors. In an effort to find more effective cisplatin-based nano-drugs with less nephrotoxic effect, the current 2011-2022 review study was conducted to investigate some of the nanotechnology-based methods that have successfully been able to mitigate CDDP-induced nephrotoxicity. Accordingly, although cisplatin can cause renal failures through inducing mitochondria dysfunction, oxidative stress, lipid peroxidation and endoplasmic reticulum stress, some CDDP-based nano-carriers have been able to reverse a wide range of these advert effects. Based on the obtained results, it was found that the use of different metallic and polymeric nanoparticles can help renal cells to strengthen their antioxidant systems and stay alive through reducing CDDP-induced ROS generation, inhibiting apoptosis-related pathways and maintaining the integrity of the mitochondrial membrane. For example, nanocurcumin could inhibit oxidative stress and acting as a ROS scavenger. CONPs could reduce lipid peroxidation and pro-inflammatory cytokines. CDDP-loaded silver nanoparticles (AgNPs) could inhibit mitochondria-mediated apoptosis. In addition, tea polyphenol-functionalized SeNPs (Se@TE) NPs could mitigate the increased level of dephosphorylated AKT, phosphorylated p38 MAPK and phosphorylated c-Jun N-terminal kinase (JNK) induced by cisplatin. Moreover, exosomes mitigated cisplatin-induced renal damage through inhibiting Bcl2 and increasing Bim, Bid, Bax, cleaved caspase-9, and cleaved caspase-3. Hence, nanoparticle-based techniques are promising drug delivery systems for cisplatin so that some of them, such as lipoplatins and nanocurcumins, have even reached phases 1-3 trials.

Urolithins: a Comprehensive Update on their Metabolism, Bioactivity, and Associated Gut Microbiota

Urolithins, metabolites produced by the gut microbiota from the polyphenols ellagitannins and ellagic acid, are discovered by the research group in humans almost 20 years ago. Pioneering research suggests urolithins as pleiotropic bioactive contributors to explain the health benefits after consuming ellagitannin-rich sources (pomegranates, walnuts, strawberries, etc.). Here, this study comprehensively updates the knowledge on urolithins, emphasizing the review of the literature published during the last 5 years. To date, 13 urolithins and their corresponding conjugated metabolites (glucuronides, sulfates, etc.) have been described and, depending on the urolithin, detected in different human fluids and tissues (urine, blood, feces, breastmilk, prostate, colon, and breast tissues). There has been a substantial advance in the research on microorganisms involved in urolithin production, along with the compositional and functional characterization of the gut microbiota associated with urolithins metabolism that gives rise to the so-called urolithin metabotypes (UM-A, UM-B, and UM-0), relevant in human health. The design of in vitro studies using physiologically relevant assay conditions (molecular forms and concentrations) is still a pending subject, making some reported urolithin activities questionable. In contrast, remarkable progress has been made in the research on the safety, bioactivity, and associated mechanisms of urolithin A, including the first human interventions.

MicroRNAs Involved in Intrinsic Apoptotic Pathway during Cisplatin-Induced Nephrotoxicity: Potential Use of Natural Products against DDP-Induced Apoptosis

Cisplatin (cis-diamminedichloroplatinum (II), DDP) is an antineoplastic agent widely used in the treatment of solid tumors because of its extensive cytotoxic activity. However, the main limiting side effect of DDP use is nephrotoxicity, a rapid deterioration in kidney function due to toxic chemicals. Several studies have shown that epigenetic processes are involved in DDP-induced nephrotoxicity. Noncoding RNAs (ncRNAs), a class of epigenetic processes, are molecules that regulate gene expression under physiological and pathological conditions. MicroRNAs (miRNAs) are the most characterized class of ncRNAs and are engaged in many cellular processes. In this review, we describe how different miRNAs regulate some pathways leading to cell death by apoptosis, specifically the intrinsic apoptosis pathway. Accordingly, many classes of natural products have been tested for their ability to prevent DDP-induced apoptosis. The study of epigenetic regulation for underlying cell death is still being studied, which will allow new strategies for the diagnosis and therapy of this unwanted disease, which is presented as a side effect of antineoplastic treatment.

The Therapeutic Relevance of Urolithins, Intestinal Metabolites of Ellagitannin-Rich Food: A Systematic Review of In Vivo Studies

The therapeutic effects of food rich in ellagitannins have been established to stem from its microbial metabolite, urolithin. Over the past decade, there has been a growing trend in urolithin research pertaining to its pharmacological properties. The purpose of this systematic review is to collate and synthesise all available data on urolithin’s therapeutic ability, to highlight its potential as a pharmaceutical agent, and prospective direction on future research. Methods: This systematic review was written based on the PRISMA guideline and was conducted across Ovid via Embase, Ovid MEDLINE, Cochrane Central Register for Controlled Trials, and Web of Science Core Collection. Results: A total of 41 animal studies were included in this systematic review based on the appropriate keyword. The included studies highlighted the neuroprotective, anti-metabolic disorder activity, nephroprotective, myocardial protective, anti-inflammatory, and musculoskeletal protection of urolithin A, B, and its synthetic analogue methylated urolithin A. The Sirt1, AMPK, and PI3K/AKT/mTOR signalling pathways were reported to be involved in the initiation of autophagy and mitochondrial biogenesis by urolithin A. Conclusions: This review methodically discusses the therapeutic prospects of urolithins and provides scientific justification for the potential development of urolithin A as a potent natural mitophagy inducer for anti-ageing purposes.

Health functions and related molecular mechanisms of ellagitannin-derived urolithins

Ellagitannins are vital bioactive polyphenols that are widely distributed in a variety of plant-based foods. The main metabolites of ellagitannins are urolithins, and current research suggests that urolithins provide a variety of health benefits. This review focused on the role of the gut bacteria in the conversion of ellagitannins to urolithins. Based on the results of in vitro and in vivo studies, the health benefits of urolithins, including antioxidant, anti-inflammatory, anti-cancer, anti-obesity, anti-diabetic, anti-aging, cardiovascular protective, neuroprotective, kidney protective, and muscle mass protective effects, were thoroughly outlined, with a focus on their associated molecular mechanisms. Finally, we briefly commented on urolithins' safety. Overall, urolithins' diverse health benefits indicate the potential utilization of ellagitannins and urolithins in the creation of functional foods and nutraceuticals to treat and prevent some chronic diseases.

Paclitaxel and Urolithin A Prevent Histamine-Induced Neurovascular Breakdown Alike, in an Ex Vivo Rat Eye Model

Neurovascular eye problems are better prevented than managed or treated. Despite growing concern of occurrence in aging populations and development secondary to diseases such as diabetes and hypertension, we currently have very few options to tackle this global problem. Creating effective and high-throughput screening strategies is as important as the intervention itself. Here, we present for the first time a robust ex vivo rat eye model of histamine-induced vascular damage for investigating the therapeutic potential of paclitaxel (PTX) and urolithin A (UA) as alternatives to dexamethasone for preventing vascular damage in the retina. Extensive loss of vascularization and apoptosis were observed in the histamine-challenged group and successfully prevented in the intervention groups, more significantly in the PTX and UA. These important early results indicate that PTX and UA could be developed as potential preventive strategies for a wide variety of retinal diseases.

Immunometabolic rewiring of tubular epithelial cells in kidney disease

Kidney tubular epithelial cells (TECs) have a crucial role in the damage and repair response to acute and chronic injury. To adequately respond to constant changes in the environment, TECs have considerable bioenergetic needs, which are supported by metabolic pathways. Although little is known about TEC metabolism, a number of ground-breaking studies have shown that defective glucose metabolism or fatty acid oxidation in the kidney has a key role in the response to kidney injury. Imbalanced use of these metabolic pathways can predispose TECs to apoptosis and dedifferentiation, and contribute to lipotoxicity and kidney injury. The accumulation of lipids and aberrant metabolic adaptations of TECs during kidney disease can also be driven by receptors of the innate immune system. Similar to their actions in innate immune cells, pattern recognition receptors regulate the metabolic rewiring of TECs, causing cellular dysfunction and lipid accumulation. TECs should therefore be considered a specialized cell type - like cells of the innate immune system - that is subject to regulation by immunometabolism. Targeting energy metabolism in TECs could represent a strategy for metabolically reprogramming the kidney and promoting kidney repair.

Urolithin A improves muscle strength, exercise performance, and biomarkers of mitochondrial health in a randomized trial in middle-aged adults

Targeting mitophagy to activate the recycling of faulty mitochondria during aging is a strategy to mitigate muscle decline. We present results from a randomized, placebo-controlled trial in middle-aged adults where we administer a postbiotic compound Urolithin A (Mitopure), a known mitophagy activator, at two doses for 4 months (NCT03464500). The data show significant improvements in muscle strength (∼12%) with intake of Urolithin A. We observe clinically meaningful improvements with Urolithin A on aerobic endurance (peak oxygen oxygen consumption [VO₂]) and physical performance (6 min walk test) but do not notice a significant improvement on peak power output (primary endpoint). Levels of plasma acylcarnitines and C-reactive proteins are significantly lower with Urolithin A, indicating higher mitochondrial efficiency and reduced inflammation. We also examine expression of proteins linked to mitophagy and mitochondrial metabolism in skeletal muscle and find a significant increase with Urolithin A administration. This study highlights the benefit of Urolithin A to improve muscle performance.

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Oral supplementation with Urolithin A increases muscle strength

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High dose of Urolithin A positively impacts exercise-performance measures

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An increase in mitophagy proteins in human skeletal muscle observed in parallel

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Supplementation is safe and increases circulating levels of Urolithin A

Urolithin A Nanoparticle Therapy for Cisplatin-Induced Acute Kidney Injury

Cisplatin continues to be one of the frontline cytotoxic drugs. However, cisplatin-induced acute kidney injury (AKI) remains a major unmet medical need without any approved pharmacological interventions. The involvement of reactive oxygen species generation and activation of inflammatory and apoptotic pathways in the pathogenesis of cisplatin-induced AKI prompts the use of natural anti-inflammatory compounds. In this context, resolution of inflammation using natural antioxidant and anti-inflammatory such as urolithin A (UA) could prove beneficial. In the end, testing such combinations in models to eliminate the possibility that UA stimulates tumor growth or compromises the potency of cisplatin could prove useful for clinical translation of adjuvant therapies.

Nephrotoxicity in cancer treatment: An update

It has been estimated that nearly 80% of anticancer drug-treated patients receive potentially nephrotoxic drugs, while the kidneys play a central role in the excretion of anticancer drugs. Nephrotoxicity has long been a serious complication that hampers the effectiveness of cancer treatment and continues to influence both mortality and length of hospitalization among cancer patients exposed to either conventional cytotoxic agents or targeted therapies. Kidney injury arising from anticancer drugs tends to be associated with preexisting comorbidities, advanced cancer stage, and the use of concomitant non-chemotherapeutic nephrotoxic drugs. Despite the prevalence and impact of kidney injury on therapeutic outcomes, the field is sorely lacking in an understanding of the mechanisms driving cancer drug-induced renal pathophysiology, resulting in quite limited and largely ineffective management of anticancer drug-induced nephrotoxicity. Consequently, there is a clear imperative for understanding the basis for nephrotoxic manifestations of anticancer agents for the successful management of kidney injury by these drugs. This article provides an overview of current preclinical research on the nephrotoxicity of cancer treatments and highlights prospective approaches to mitigate cancer therapy-related renal toxicity.

Urolithins: The Colon Microbiota Metabolites as Endocrine Modulators: Prospects and Perspectives

Selective estrogen receptor modulators (SERMs) have been used in hormone related disorders, and their role in clinical medicine is evolving. Tamoxifen and raloxifen are the most commonly used synthetic SERMs, and their long-term use are known to create side effects. Hence, efforts have been directed to identify molecules which could retain the beneficial effects of estrogen, at the same time produce minimal side effects. Urolithins, the products of colon microbiota from ellagitannin rich foodstuff, have immense health benefits and have been demonstrated to bind to estrogen receptors. This class of compounds holds promise as therapeutic and nutritional supplement in cardiovascular disorders, osteoporosis, muscle health, neurological disorders, and cancers of breast, endometrium, and prostate, or, in essence, most of the hormone/endocrine-dependent diseases. One of our findings from the past decade of research on SERMs and estrogen modulators, showed that pomegranate, one of the indirect but major sources of urolithins, can act as SERM. The prospect of urolithins to act as agonist, antagonist, or SERM will depend on its structure; the estrogen receptor conformational change, availability and abundance of co-activators/co-repressors in the target tissues, and also the presence of other estrogen receptor ligands. Given that, urolithins need to be carefully studied for its SERM activity considering the pleotropic action of estrogen receptors and its numerous roles in physiological systems. In this review, we unveil the possibility of urolithins as a potent SERM, which we are currently investigating, in the hormone dependent tissues.

Urolithin A alleviates acute kidney injury induced by renal ischemia reperfusion through the p62-Keap1-Nrf2 signaling pathway

Acute kidney injury (AKI) induced by renal ischemia reperfusion (RIR) is typically observed in renal surgeries and is a leading cause of renal failure. However, there is still an unmet medical need currently in terms of clinical treatments. Herein, we report the effect of Urolithin A (UA) in a mouse RIR model, wherein we demonstrated its underlying mechanism both in vitro and in vivo. The expression levels of p62 and Keap1 significantly decreased, while that of nuclear Nrf2 increased in vitro in a hypoxia cell model after UA treatment. Furthermore, the apoptosis of tubular cells was attenuated and the reactive oxygen species (ROS) levels were reduced in the kidneys in a mouse RIR model after UA administration. In this study, we demonstrated that UA can alleviate oxidative stress and promote autophagy by activating the p62-Keap1-Nrf2 signaling pathway, which could protect the kidneys from ischemia reperfusion injury.

A mechanistic insight into the biological activities of urolithins as gut microbial metabolites of ellagitannins

Urolithins are the gut metabolites produced from ellagitannin-rich foods such as pomegranates, tea, walnuts, as well as strawberries, raspberries, blackberries, and cloudberries. Urolithins are of growing interest due to their various biological activities including cardiovascular protection, anti-inflammatory activity, anticancer properties, antidiabetic activity, and antiaging properties. Several studies mostly based on in vitro and in vivo experiments have investigated the potential mechanisms of urolithins which support the beneficial effects of urolithins in the treatment of several diseases such as Alzheimer's disease, type 2 diabetes mellitus, liver disease, cardiovascular disease, and various cancers. It is now obvious that urolithins can involve several cellular mechanisms including inhibition of MDM2-p53 interaction, modulation of mitogen-activated protein kinase pathway, and suppressing nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activity. Antiaging activity is the most appealing and probably the most important property of urolithin A that has been investigated in depth in recent studies, owing to its unique effects on activation of mitophagy and mitochondrial biogenesis. A recent clinical trial showed that urolithin A is safe up to 2,500 mg/day and can improve mitochondrial biomarkers in elderly patients. Regarding the importance of mitochondria in the pathophysiology of many diseases, urolithins merit further research especially in clinical trials to unravel more aspects of their clinical significance. Besides the nutritional value of urolithins, recent studies proved that urolithins can be used as pharmacological agents to prevent or cure several diseases. Here, we comprehensively review the potential role of urolithins as new therapeutic agents with a special focus on the molecular pathways that have been involved in their biological effects. The pharmacokinetics of urolithins is also included.

Application of nanotechnology in acute kidney injury: From diagnosis to therapeutic implications

Acute kidney injury (AKI), a major health issue concerning ~50% of patients treated in intensive care units, generally leads to severe renal damage associated with high mortality rate. The application of nanotechnology for the management of AKI has profound potential of further development, providing innovative strategies for predicting the early onset and progression of renal disease and improving the treatment efficacy of the life-threating AKI. This review has comprehensively summarized the nanomedicines in the application of AKI diagnosis and emphatically discussed the unique potential of various nanotechnology-based drug delivery systems (e.g., polymeric nanoparticles, organic nanoparticles, inorganic nanoparticles, lipid-based nanoparticles, hydrogels etc.) in the treatment of AKI, allowing for improved therapeutic index by enhancing both efficacy and safety concurrently. These approaches may mechanically mitigate oxidative stress, inflammation, and mitochondrial and other organellar damage, etc. In addition, the combination of nanotechnology with stem cells-based therapy or gene therapy has been explored for reducing renal tissues damage and promoting kidney repair or recovery from AKI. The review provides insights into the synthesis, advantages, and limitations of innovative nanomedicine application in the early detection and effective treatment of AKI.

Epigenetic Mechanisms Involved in Cisplatin-Induced Nephrotoxicity: An Update

Cisplatin is an antineoplastic drug used for the treatment of many solid tumors. Among its various side effects, nephrotoxicity is the most detrimental. In recent years, epigenetic regulation has emerged as a modulatory mechanism of cisplatin-induced nephrotoxicity, involving non-coding RNAs, DNA methylation and histone modifications. These epigenetic marks alter different signaling pathways leading to damage and cell death. In this review, we describe how different epigenetic modifications alter different pathways leading to cell death by apoptosis, autophagy, necroptosis, among others. The study of epigenetic regulation is still under development, and much research remains to fully determine the epigenetic mechanisms underlying cell death, which will allow leading new strategies for the diagnosis and therapy of this disease.

Impact of the Natural Compound Urolithin A on Health, Disease, and Aging

Urolithin A (UA) is a natural compound produced by gut bacteria from ingested ellagitannins (ETs) and ellagic acid (EA), complex polyphenols abundant in foods such as pomegranate, berries, and nuts. UA was discovered 40 years ago, but only recently has its impact on aging and disease been explored. UA enhances cellular health by increasing mitophagy and mitochondrial function and reducing detrimental inflammation. Several preclinical studies show how UA protects against aging and age-related conditions affecting muscle, brain, joints, and other organs. In humans, benefits of UA supplementation in the muscle are supported by recent clinical trials in elderly people. Here, we review the state of the art of UA's biology and its translational potential as a nutritional intervention in humans.

Mitochondrial quality control in kidney injury and repair

Mitochondria are essential for the activity, function and viability of eukaryotic cells and mitochondrial dysfunction is involved in the pathogenesis of acute kidney injury (AKI) and chronic kidney disease, as well as in abnormal kidney repair after AKI. Multiple quality control mechanisms, including antioxidant defence, protein quality control, mitochondrial DNA repair, mitochondrial dynamics, mitophagy and mitochondrial biogenesis, have evolved to preserve mitochondrial homeostasis under physiological and pathological conditions. Loss of these mechanisms may induce mitochondrial damage and dysfunction, leading to cell death, tissue injury and, potentially, organ failure. Accumulating evidence suggests a role of disturbances in mitochondrial quality control in the pathogenesis of AKI, incomplete or maladaptive kidney repair and chronic kidney disease. Moreover, specific interventions that target mitochondrial quality control mechanisms to preserve and restore mitochondrial function have emerged as promising therapeutic strategies to prevent and treat kidney injury and accelerate kidney repair. However, clinical translation of these findings is challenging owing to potential adverse effects, unclear mechanisms of action and a lack of knowledge of the specific roles and regulation of mitochondrial quality control mechanisms in kidney resident and circulating cell types during injury and repair of the kidney.

Emerging Role of MiR-192-5p in Human Diseases

MicroRNAs (miRNAs) are a type of small non-coding RNAs that play an essential role in numerous biological processes by regulating the post-transcriptional expression of target genes. Recent studies have demonstrated that miR-192-5p, a member of the miR-192 family, partakes in several human diseases, especially various cancers, including cancers of the lung, liver, and breast. Importantly, the levels of miR-192-5p are abundant in biofluids, including the serum and urine, and the exosomal levels of miR-192-5p in circulation can aid in the diagnosis and prognosis of various diseases, such as chronic hepatitis B (CHB) infection disease. Notably, recent studies suggest that miR-192-5p is regulated by long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs). However, there are no comprehensive overviews on the role of miR-192-5p in human diseases. This review discusses the significant studies on the role of miR-192-5p in various human diseases, with special emphasis on the diseases of the respiratory and digestive systems.

Nanoparticles that do not compete with endogenous ligands - Molecular characterization in vitro, acute safety in canine, and interspecies pharmacokinetics modeling to humans

A vast majority, if not all of the receptor-mediated drug delivery systems utilize nanoparticles that are conjugated to physiological mimic ligands, with testing restricted to in vitro and rodent models. In this report, we present for the first time, a full spectrum characterization of transferrin receptor 1 (TfR1)-targeted polymeric nanoparticles (abbreviated, P2Ns-GA) that do not compete with endogenous transferrin, and serve as a versatile platform for oral drug delivery. Based on endocytosis inhibitors and receptor knockdown, the cellular uptake of P2Ns-GA is clathrin-mediated and dependent on TfR1 expression, but other trafficking mechanisms, particularly those involving caveolae/lipid rafts, can also play a role. The utility of P2Ns-GA in promoting the oral bioavailability of encapsulated compounds is demonstrated with a hydrophobic polyphenol, urolithin A (UA). When compared against plain UA or UA in ligand-free nanoparticles, UA-loaded P2Ns-GA led to markedly higher plasma concentrations among healthy canines, with no adverse health effects observed after oral dosing. Finally, a semi-mechanistic pharmacokinetic model was developed using both rat and dog datasets to quantitatively evaluate the effect of P2Ns-GA on oral bioavailability of UA. The model was allometrically scaled to humans to simulate clinical pharmacokinetics of plain UA and UA-loaded P2Ns-GA following oral administration.

Immunomodulatory Role of Urolithin A on Metabolic Diseases

Urolithin A (UroA) is a gut metabolite produced from ellagic acid-containing foods such as pomegranates, berries, and walnuts. UroA is of growing interest due to its therapeutic potential for various metabolic diseases based on immunomodulatory properties. Recent advances in UroA research suggest that UroA administration attenuates inflammation in various tissues, including the brain, adipose, heart, and liver tissues, leading to the potential delay or prevention of the onset of Alzheimer’s disease, type 2 diabetes mellitus, and non-alcoholic fatty liver disease. In this review, we focus on recent updates of the anti-inflammatory function of UroA and summarize the potential mechanisms by which UroA may help attenuate the onset of diseases in a tissue-specific manner. Therefore, this review aims to shed new insights into UroA as a potent anti-inflammatory molecule to prevent immunometabolic diseases, either by dietary intervention with ellagic acid-rich food or by UroA administration as a new pharmaceutical drug.

COVID-19: fighting the invisible enemy with microRNAs

INTRODUCTION

The novel coronavirus (CoV) disease 2019 (COVID-19) is a viral infection that causes severe acute respiratory syndrome (SARS). It is believed that early reports of COVID-19 cases were noticed in December 2019 and soon after it became a global public health emergency. It is advised that COVID-19 transmits through human to human contact and in most cases, it remains asymptomatic. Several approaches are being utilized to control the outbreak of this fatal viral disease. microRNAs (miRNAs) are known signature therapeutic tool for the viral diseases; they are small non-coding RNAs that target the mRNAs to inhibit their post-transcriptional expression, therefore, impeding their functions, can serve as watchdogs or micromanagers in the cells.

AREAS COVERED

This review work delineated COVID-19 and its association with SARS and Middle East respiratory syndrome (MERS), the possible role of miRNAs in the pathogenesis of COVID-19, and therapeutic potential of miRNAs and their effective delivery to treat COVID-19.

EXPERT OPINION

This review highlighted the importance of various miRNAs and their potential role in fighting with this pandemic as therapeutic molecules utilizing nanotechnology.

Novel Oral Nanoparticle Formulation of Sustained Release Naloxone with Mild Withdrawal Symptoms in Mice

Chronic use of opioids can lead to tolerance, dependence, abuse, and addiction. This in turn can result in dose escalation and opioid overdose. Opioid overdose can be fatal due to severe opioid-induced respiratory depression (OIRD). Naloxone, a nonspecific antagonist of the mu-opioid receptors, is used for the reversal of OIRD. However, one of the major challenges of using naloxone is its short elimination half-life, which is significantly shorter compared to many opioid analgesics. Thus, renarcotization and rapid return to full respiratory depression might occur, specifically in individuals who have taken large doses or long-acting opioid formulations. Additionally, because of the very low oral bioavailability of naloxone, an oral formulation is not currently available. This study examines in mice a novel oral formulation of naloxone based on polymer nanoparticles (NP-naloxone). A single dose of 1 or 5 mg/kg NP-naloxone was highly effective at inhibiting the activating effects of repeated administration of 10 mg/kg morphine for at least up to 24 h. Onset of action was approximately 5 min. Reversal of morphine-induced locomotion was already detected within 1 min and a full effect of returning to baseline activity levels was observed within 5 min. Importantly, at 1 mg/kg, NP-naloxone precipitated very minimal withdrawal behaviors. At the 5 mg/kg dose, NP-naloxone precipitated approximately 40% of the jumping withdrawal behaviors of injectable naloxone. Thus, this study demonstrates that orally administered naloxone based on polymer nanoparticles has high potential to be developed to circumvent OIRD and withdrawal symptoms.