Sirt1 is essential for resveratrol enhancement of hypoxia-induced autophagy in the type 2 diabetic nephropathy rat

Cerliponase alfa decreases Aβ load and alters autophagy- related pathways in mouse hippocampal neurons exposed to fAβ1-42

Extracellular aggregation of amyloid-beta (Aβ) in the brain plays a central role in the onset and progression of Alzheimer's disease (AD). Moreover, intraneuronal accumulation of Aβ via oligomer internalization might play an important role in the progression of AD. Deficient autophagy, which is a lysosomal degradation process, occurs during the early stages of AD. Tripeptidyl peptidase-1 (TPP1) functions as a lysosomal enzyme, and TPP1 gene mutations are associated with type 2 late infantile neuronal ceroid lipofuscinosis (LINCL). Nevertheless, there is little information about the role of TPP1 in the pathogenesis of AD; therefore, the present study aimed to measure the decrease in intraneuronal Aβ accumulation by a recombinant analog of the TPP1 enzyme, cerliponase alfa (CER) (Brineura®), and to determine whether autophagy pathways play a role in this decrease. In this study, endogenous Aβ accumulation was induced by fAβ1-42 (a toxic fragment of full-length Aβ) exposure, and mouse hippocampal neuronal cells (HT-22) were treated with CER (human recombinant rhTPP1 1 mg mL-1). Soluble Aβ, TPP1, and the proteins involved in autophagy, including mammalian target of rapamycin (p-mTOR/mTOR), p62/sequestosome-1 (p62/SQSTM1), and microtubule-associated protein 1 A/1B-light chain 3 (LC3), were evaluated using western blotting. The sirtuin-1, beclin-1, and Atg5 genes were also studied using RT-PCR. Aβ and TPP1 localizations were observed via immunocytochemistry. CER reduced the Aβ load in HT-22 cells by inducing TPP1 expression and converting pro-TPP1 into the mature form. Furthermore, exposure to CER and fAβ1-42 induced the autophagy-regulatory/related pathways in HT-22 cells and exposure to CER alone increased sirtuin-1 activity. Based on the present findings, we suggest that augmentation of TPP1 with enzyme replacement therapy may be a potential therapeutic option for the treatment of AD.

The role of mitochondrial dysfunction in kidney injury and disease

Mitochondria are the main sites of aerobic respiration in the cell and mainly provide energy for the organism, and play key roles in adenosine triphosphate (ATP) synthesis, metabolic regulation, and cell differentiation and death. Mitochondrial dysfunction has been identified as a contributing factor to a variety of diseases. The kidney is rich in mitochondria to meet energy needs, and stable mitochondrial structure and function are essential for normal kidney function. Recently, many studies have shown a link between mitochondrial dysfunction and kidney disease, maintaining mitochondrial homeostasis has become an important target for kidney therapy. In this review, we integrate the role of mitochondrial dysfunction in different kidney diseases, and specifically elaborate the mechanism of mitochondrial reactive oxygen species (mtROS), autophagy and ferroptosis involved in the occurrence and development of kidney diseases, providing insights for improved treatment of kidney diseases.

Is resveratrol really effective in kidney disease?: A different perspective than ever before

BACKGROUND

Chronic kidney disease (CKD) is a global health problem and it is stated that the use of resveratrol supplement contributes to the protection of kidney health. In this study, it was aimed to evaluate the effect of resveratrol supplementation on kidney function, inflammation and histopathological findings in rats with experimental adenine-induced kidney damage.

METHODS

Three different groups of 10 randomly selected rats were formed. The first group was the negative control group, the second group was the uremic control group (KDG), and the third group was the group in which uremia was created and resveratrol was applied (RG). Kidney damage was induced by administration of 200 mg/kg adenine. Resveratrol supplementation was administered at 20 mg/kg after kidney damage. Serum urea, creatinine, indoxyl sulfate (IS), p-cresol, glomerular filtration rate, C-reactive protein (CRP); interleukin (IL)-6 and tumor necrosis factor (TNF)-α gene expression levels and histopathological findings were evaluated.

RESULTS

It was determined that resveratrol supplement applied after the formation of connective tissue in renal failure didn't have an improvement effect on the urine amount, kidney function and inflammatory parameters and histopathological changes (p > 0.05). Just, the increase in the CRP value of KDG (p < 0.05) was not observed in RG.

CONCLUSION

The findings suggest that resveratrol administered after kidney damage with adenine has no effect on kidney disease.

Targeting autophagy with natural products as a potential therapeutic approach for diabetic microangiopathy

As the quality of life improves, the incidence of diabetes mellitus and its microvascular complications (DMC) continues to increase, posing a threat to people's health and wellbeing. Given the limitations of existing treatment, there is an urgent need for novel approaches to prevent and treat DMC. Autophagy, a pivotal mechanism governing metabolic regulation in organisms, facilitates the removal of dysfunctional proteins and organelles, thereby sustaining cellular homeostasis and energy generation. Anomalous states in pancreatic β-cells, podocytes, Müller cells, cardiomyocytes, and Schwann cells in DMC are closely linked to autophagic dysregulation. Natural products have the property of being multi-targeted and can affect autophagy and hence DMC progression in terms of nutrient perception, oxidative stress, endoplasmic reticulum stress, inflammation, and apoptosis. This review consolidates recent advancements in understanding DMC pathogenesis via autophagy and proposes novel perspectives on treating DMC by either stimulating or inhibiting autophagy using natural products.

SIRT1: a promising therapeutic target in type 2 diabetes mellitus

A significant increase in the worldwide incidence and prevalence of type 2 diabetic mellitus (T2DM) has elevated the need for studies on novel and effective therapeutic strategies. Sirtuin 1 (SIRT1) is an NAD + dependent protein deacetylase with a critical function in the regulation of glucose/lipid metabolism, insulin resistance, inflammation, oxidative stress, and mitochondrial function. SIRT1 is also involved in the regulation of insulin secretion from pancreatic β-cells and protecting these cells from inflammation and oxidative stress-mediated tissue damages. In this regard, major SIRT1 activators have been demonstrated to exert a beneficial impact in reversing T2DM-related complications including cardiomyopathy, nephropathy, retinopathy, and neuropathy, hence treating T2DM. Therefore, an accumulating number of recent studies have investigated the efficacy of targeting SIRT1 as a therapeutic strategy in T2DM. In this review we aimed to discuss the current understanding of the physiological and biological roles of SIRT1, then its implication in the pathogenesis of T2DM, and the therapeutic potential of SIRT1 in combating T2DM.

Cornerstone Cellular Pathways for Metabolic Disorders and Diabetes Mellitus: Non-Coding RNAs, Wnt Signaling, and AMPK

Metabolic disorders and diabetes (DM) impact more than five hundred million individuals throughout the world and are insidious in onset, chronic in nature, and yield significant disability and death. Current therapies that address nutritional status, weight management, and pharmacological options may delay disability but cannot alter disease course or functional organ loss, such as dementia and degeneration of systemic bodily functions. Underlying these challenges are the onset of aging disorders associated with increased lifespan, telomere dysfunction, and oxidative stress generation that lead to multi-system dysfunction. These significant hurdles point to the urgent need to address underlying disease mechanisms with innovative applications. New treatment strategies involve non-coding RNA pathways with microRNAs (miRNAs) and circular ribonucleic acids (circRNAs), Wnt signaling, and Wnt1 inducible signaling pathway protein 1 (WISP1) that are dependent upon programmed cell death pathways, cellular metabolic pathways with AMP-activated protein kinase (AMPK) and nicotinamide, and growth factor applications. Non-coding RNAs, Wnt signaling, and AMPK are cornerstone mechanisms for overseeing complex metabolic pathways that offer innovative treatment avenues for metabolic disease and DM but will necessitate continued appreciation of the ability of each of these cellular mechanisms to independently and in unison influence clinical outcome.

The impact of aging and oxidative stress in metabolic and nervous system disorders: programmed cell death and molecular signal transduction crosstalk

Life expectancy is increasing throughout the world and coincides with a rise in non-communicable diseases (NCDs), especially for metabolic disease that includes diabetes mellitus (DM) and neurodegenerative disorders. The debilitating effects of metabolic disorders influence the entire body and significantly affect the nervous system impacting greater than one billion people with disability in the peripheral nervous system as well as with cognitive loss, now the seventh leading cause of death worldwide. Metabolic disorders, such as DM, and neurologic disease remain a significant challenge for the treatment and care of individuals since present therapies may limit symptoms but do not halt overall disease progression. These clinical challenges to address the interplay between metabolic and neurodegenerative disorders warrant innovative strategies that can focus upon the underlying mechanisms of aging-related disorders, oxidative stress, cell senescence, and cell death. Programmed cell death pathways that involve autophagy, apoptosis, ferroptosis, and pyroptosis can play a critical role in metabolic and neurodegenerative disorders and oversee processes that include insulin resistance, β-cell function, mitochondrial integrity, reactive oxygen species release, and inflammatory cell activation. The silent mating type information regulation 2 homolog 1 (Saccharomyces cerevisiae) (SIRT1), AMP activated protein kinase (AMPK), and Wnt1 inducible signaling pathway protein 1 (WISP1) are novel targets that can oversee programmed cell death pathways tied to β-nicotinamide adenine dinucleotide (NAD+), nicotinamide, apolipoprotein E (APOE), severe acute respiratory syndrome (SARS-CoV-2) exposure with coronavirus disease 2019 (COVID-19), and trophic factors, such as erythropoietin (EPO). The pathways of programmed cell death, SIRT1, AMPK, and WISP1 offer exciting prospects for maintaining metabolic homeostasis and nervous system function that can be compromised during aging-related disorders and lead to cognitive impairment, but these pathways have dual roles in determining the ultimate fate of cells and organ systems that warrant thoughtful insight into complex autofeedback mechanisms.

Regulation of autophagy by natural polyphenols in the treatment of diabetic kidney disease: therapeutic potential and mechanism

Diabetic kidney disease (DKD) is a major microvascular complication of diabetes and a leading cause of end-stage renal disease worldwide. Autophagy plays an important role in maintaining cellular homeostasis in renal physiology. In DKD, the accumulation of advanced glycation end products induces decreased renal autophagy-related protein expression and transcription factor EB (TFEB) nuclear transfer, leading to impaired autophagy and lysosomal function and blockage of autophagic flux. This accelerates renal resident cell injury and apoptosis, mediates macrophage infiltration and phenotypic changes, ultimately leading to aggravated proteinuria and fibrosis in DKD. Natural polyphenols show promise in treating DKD by regulating autophagy and promoting nuclear transfer of TFEB and lysosomal repair. This review summarizes the characteristics of autophagy in DKD, and the potential application and mechanisms of some known natural polyphenols as autophagy regulators in DKD, with the goal of contributing to a deeper understanding of natural polyphenol mechanisms in the treatment of DKD and promoting the development of their applications. Finally, we point out the limitations of polyphenols in current DKD research and provide an outlook for their future research.

Tubular injury in diabetic kidney disease: molecular mechanisms and potential therapeutic perspectives

Diabetic kidney disease (DKD) is a chronic complication of diabetes and the leading cause of end-stage renal disease (ESRD) worldwide. Currently, there are limited therapeutic drugs available for DKD. While previous research has primarily focused on glomerular injury, recent studies have increasingly emphasized the role of renal tubular injury in the pathogenesis of DKD. Various factors, including hyperglycemia, lipid accumulation, oxidative stress, hypoxia, RAAS, ER stress, inflammation, EMT and programmed cell death, have been shown to induce renal tubular injury and contribute to the progression of DKD. Additionally, traditional hypoglycemic drugs, anti-inflammation therapies, anti-senescence therapies, mineralocorticoid receptor antagonists, and stem cell therapies have demonstrated their potential to alleviate renal tubular injury in DKD. This review will provide insights into the latest research on the mechanisms and treatments of renal tubular injury in DKD.

Cellular Metabolism: A Fundamental Component of Degeneration in the Nervous System

It is estimated that, at minimum, 500 million individuals suffer from cellular metabolic dysfunction, such as diabetes mellitus (DM), throughout the world. Even more concerning is the knowledge that metabolic disease is intimately tied to neurodegenerative disorders, affecting both the central and peripheral nervous systems as well as leading to dementia, the seventh leading cause of death. New and innovative therapeutic strategies that address cellular metabolism, apoptosis, autophagy, and pyroptosis, the mechanistic target of rapamycin (mTOR), AMP activated protein kinase (AMPK), growth factor signaling with erythropoietin (EPO), and risk factors such as the apolipoprotein E (APOE-ε4) gene and coronavirus disease 2019 (COVID-19) can offer valuable insights for the clinical care and treatment of neurodegenerative disorders impacted by cellular metabolic disease. Critical insight into and modulation of these complex pathways are required since mTOR signaling pathways, such as AMPK activation, can improve memory retention in Alzheimer's disease (AD) and DM, promote healthy aging, facilitate clearance of β-amyloid (Aß) and tau in the brain, and control inflammation, but also may lead to cognitive loss and long-COVID syndrome through mechanisms that can include oxidative stress, mitochondrial dysfunction, cytokine release, and APOE-ε4 if pathways such as autophagy and other mechanisms of programmed cell death are left unchecked.

β Cell and Autophagy: What Do We Know?

Pancreatic β cells are central to glycemic regulation through insulin production. Studies show autophagy as an essential process in β cell function and fate. Autophagy is a catabolic cellular process that regulates cell homeostasis by recycling surplus or damaged cell components. Impaired autophagy results in β cell loss of function and apoptosis and, as a result, diabetes initiation and progress. It has been shown that in response to endoplasmic reticulum stress, inflammation, and high metabolic demands, autophagy affects β cell function, insulin synthesis, and secretion. This review highlights recent evidence regarding how autophagy can affect β cells' fate in the pathogenesis of diabetes. Furthermore, we discuss the role of important intrinsic and extrinsic autophagy modulators, which can lead to β cell failure.

Role of sirtuins in metabolic disease-related renal injury

Poor control of metabolic diseases induces kidney injury, resulting in microalbuminuria, renal insufficiency and, ultimately, chronic kidney disease. The potential pathogenetic mechanisms of renal injury caused by metabolic diseases remain unclear. Tubular cells and podocytes of the kidney show high expression of histone deacetylases known as sirtuins (SIRT1-7). Available evidence has shown that SIRTs participate in pathogenic processes of renal disorders caused by metabolic diseases. The present review addresses the regulatory roles of SIRTs and their implications for the initiation and development of kidney damage due to metabolic diseases. SIRTs are commonly dysregulated in renal disorders induced by metabolic diseases such as hypertensive nephropathy and diabetic nephropathy. This dysregulation is associated with disease progression. Previous literature has also suggested that abnormal expression of SIRTs affects cellular biology, such as oxidative stress, metabolism, inflammation, and apoptosis of renal cells, resulting in the promotion of invasive diseases. This literature reviews the research progress made in understanding the roles of dysregulated SIRTs in the pathogenesis of metabolic disease-related kidney disorders and describes the potential of SIRTs serve as biomarkers for early screening and diagnosis of these diseases and as therapeutic targets for their treatment.

Implications of altered sirtuins in metabolic regulation and oral cancer

Sirtuins (SIRTs 1-7) are a group of histone deacetylase enzymes with a wide range of enzyme activities that target a range of cellular proteins in the nucleus, cytoplasm, and mitochondria for posttranslational modifications by acetylation (SIRT1, 2, 3, and 5) or ADP ribosylation (SIRT4, 6, and 7). A variety of cellular functions, including mitochondrial functions and functions in energy homeostasis, metabolism, cancer, longevity and ageing, are regulated by sirtuins. Compromised sirtuin functions and/or alterations in the expression levels of sirtuins may lead to several pathological conditions and contribute significantly to alterations in metabolic phenotypes as well as oral carcinogenesis. Here, we describe the basic characteristics of seven mammalian sirtuins. This review also emphasizes the key molecular mechanisms of sirtuins in metabolic regulation and discusses the possible relationships of sirtuins with oral cancers. This review will provide novel insight into new therapeutic approaches targeting sirtuins that may potentially lead to effective strategies for combating oral malignancies.

Autophagy and its therapeutic potential in diabetic nephropathy

Diabetic nephropathy (DN), the leading cause of end-stage renal disease, is the most significant microvascular complication of diabetes and poses a severe public health concern due to a lack of effective clinical treatments. Autophagy is a lysosomal process that degrades damaged proteins and organelles to preserve cellular homeostasis. Emerging studies have shown that disorder in autophagy results in the accumulation of damaged proteins and organelles in diabetic renal cells and promotes the development of DN. Autophagy is regulated by nutrient-sensing pathways including AMPK, mTOR, and Sirt1, and several intracellular stress signaling pathways such as oxidative stress and endoplasmic reticulum stress. An abnormal nutritional status and excess cellular stresses caused by diabetes-related metabolic disorders disturb the autophagic flux, leading to cellular dysfunction and DN. Here, we summarized the role of autophagy in DN focusing on signaling pathways to modulate autophagy and therapeutic interferences of autophagy in DN.

Autophagy-nutrient sensing pathways in diabetic complications

The incidence of diabetes has been increasing in recent decades which is affecting the population of both, developed and developing countries. Diabetes is associated with micro and macrovascular complications which predominantly result from hyperglycemia and disrupted metabolic pathways. Persistent hyperglycemia leads to increased reactive oxygen species (ROS) generation, formation of misfolded and abnormal proteins, and disruption of normal cellular functioning. The inability to maintain metabolic homeostasis under excessive energy and nutrient input, which induces insulin resistance, is a crucial feature during the transition from obesity to diabetes. According to various study reports, redox alterations, intracellular stress and chronic inflammation responses have all been linked to dysregulated energy metabolism and insulin resistance. Autophagy has been considered a cleansing mechanism to prevent these anomalies and restore cellular homeostasis. However, disrupted autophagy has been linked to the pathogenesis of metabolic disorders such as obesity and diabetes. Recent studies have reported that the regulation of autophagy has a beneficial role against these conditions. When there is plenty of food, nutrient-sensing pathways activate anabolism and storage, but the shortage of food activates homeostatic mechanisms like autophagy, which mobilises internal stockpiles. These nutrient-sensing pathways are well conserved in eukaryotes and are involved in the regulation of autophagy which includes SIRT1, mTOR and AMPK. The current review focuses on the role of SIRT1, mTOR and AMPK in regulating autophagy and suggests autophagy along with these nutrient-sensing pathways as potential therapeutic targets in reducing the progression of various diabetic complications.

Molecular mechanisms and physiological functions of autophagy in kidney diseases

Autophagy is a highly conserved cellular progress for the degradation of cytoplasmic contents including micromolecules, misfolded proteins, and damaged organelles that has recently captured attention in kidney diseases. Basal autophagy plays a pivotal role in maintaining cell survival and kidney homeostasis. Accordingly, dysregulation of autophagy has implicated in the pathologies of kidney diseases. In this review, we summarize the multifaceted role of autophagy in kidney aging, maladaptive repair, tubulointerstitial fibrosis and discuss autophagy-related drugs in kidney diseases. However, uncertainty still remains as to the precise mechanisms of autophagy in kidney diseases. Further research is needed to clarify the accurate molecular mechanism of autophagy in kidney diseases, which will facilitate the discovery of a promising strategy for the prevention and treatment of kidney diseases.

Antioxidant and Anti-inflammatory Properties of Resveratrol in Diabetic Nephropathy: A Systematic Review and Meta-analysis of Animal Studies

Background: Accumulated experimental evidence suggests that resveratrol may have an effect on diabetic nephropathy by inhibiting inflammation and decreasing oxidative stress. However, the credibility of the evidence for this practice is unclear. Thus, we aimed to perform a systematic review and meta-analysis of animal studies to evaluate the antioxidant and anti-inflammatory properties of resveratrol when used in the treatment of diabetic nephropathy.

Methods: Electronic bibliographic databases including PubMed, EMBASE, and Web of Science were searched for relevant studies. The methodological quality of animal studies was assessed based on the SYstematic Review Center for Laboratory animal Experimentation Risk of Bias (SYRCLE’s RoB) tool. A meta-analysis was performed based on the Cochrane Handbook for Systematic Reviews of Interventions by using RevMan 5.4 software. This study was registered within International Prospective Register of Systematic Reviews (PROSPERO) as number CRD42021293784.

Results: Thirty-six qualified studies involving 726 animals were included. There was a significant association of resveratrol with the levels of blood glucose (BG), serum creatinine (Scr), blood urea nitrogen (BUN), catalase (CAT), superoxide dismutase (SOD), malondialdehyde (MDA), glutathione (GSH), glutathione peroxidase (GPx), and interleukin-1β (IL-1β). Nevertheless, resveratrol treatment did not effectively decrease the levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). In addition, more remarkable antioxidant and hypoglycemic effects were observed in type 2 diabetic nephropathy rather than in type 1 diabetic nephropathy based on subgroup analysis.

Conclusion: In this meta-analysis, resveratrol can exert its antioxidant activities by reducing the levels of MDA and recovering the activities of SOD, CAT, GSH, and GPx. With regard to pro-inflammatory cytokines, resveratrol had a positive effect on the reduction of IL-1β. However, the analysis indicated that resveratrol had no effect on IL-6 and TNF-α levels, probably because of the methodological quality of the studies and their heterogeneity. Current evidence supports the antioxidant and anti-inflammatory properties of resveratrol, but its relationship with the levels of some inflammatory cytokines such as IL-6 and TNF-α in animals with diabetic nephropathy needs further elucidation.

SIRT1 and Autophagy: Implications in Endocrine Disorders

Autophagy is a cellular process involved in the selective degradation and recycling of dysfunctional intracellular components. It plays a crucial role in maintaining cellular homeostasis and survival by removing damaged and harmful proteins, lipids, and organelles. SIRT1, an NAD⁺-dependent multifunctional enzyme, is a key regulator of the autophagy process. Through its deacetylase activity, SIRT1 participates in the regulation of different steps of autophagy, from initiation to degradation. The levels and function of SIRT1 are also regulated by the autophagy process. Dysregulation in SIRT1-mediated autophagy hinders the proper functioning of the endocrine system, contributing to the onset and progression of endocrine disorders. This review provides an overview of the crosstalk between SIRT1 and autophagy and their implications in obesity, type-2 diabetes mellitus, diabetic cardiomyopathy, and hepatic steatosis.

SIRT1-SIRT7 in Diabetic Kidney Disease: Biological Functions and Molecular Mechanisms

Diabetic kidney disease (DKD) is a severe microvascular complication in patients with diabetes and is one of the main causes of renal failure. The current clinical treatment methods for DKD are not completely effective, and further exploration of the molecular mechanisms underlying the pathology of DKD is necessary to improve and promote the treatment strategy. Sirtuins are class III histone deacetylases, which play an important role in many biological functions, including DNA repair, apoptosis, cell cycle, oxidative stress, mitochondrial function, energy metabolism, lifespan, and aging. In the last decade, research on sirtuins and DKD has gained increasing attention, and it is important to summarize the relationship between DKD and sirtuins to increase the awareness of DKD and improve the cure rates. We have found that miRNAs, lncRNAs, compounds, or drugs that up-regulate the activity and expression of sirtuins play protective roles in renal function. Therefore, in this review, we summarize the biological functions, molecular targets, mechanisms, and signaling pathways of SIRT1-SIRT7 in DKD models. Existing research has shown that sirtuins have the potential as effective targets for the clinical treatment of DKD. This review aims to lay a solid foundation for clinical research and provide a theoretical basis to slow the development of DKD in patients.

Therapeutic potential of resveratrol in diabetic nephropathy according to molecular signaling

BACKGROUND

Diabetic nephropathy (DN) as a severe complication of diabetes mellitus (DM), is a crucial menace for human health and survival and remarkably elevates the healthcare systems' costs. Therefore, it is worth noting to identify novel preventive and therapeutic strategies to alleviate the disease conditions. Resveratrol, as a well-defined anti-diabetic/ antioxidant agent has capabilities to counteract diabetic complications. It has been predicted that resveratrol will be a fantastic natural polyphenol for diabetes therapy in the next few years.

OBJECTIVE

Accordingly, the current review aims to depict the role of resveratrol in the regulation of different signaling pathways that are involved in the reactive oxygen species (ROS) production, inflammatory processes, autophagy, and mitochondrial dysfunction, as critical contributors to DN pathophysiology.

RESULTS

The pathogenesis of DN can be multifactorial; hyperglycemia is one of the prominent risk factors of DN development that is closely related to oxidative stress. Resveratrol, as a well-defined polyphenol, has various biological and medicinal properties, including anti-diabetic, anti-inflammatory, and anti-oxidative effects.

CONCLUSION

Resveratrol prevents kidney damages that are caused by oxidative stress, enhances antioxidant capacity, and attenuates the inflammatory and fibrotic responses. For this reason, resveratrol is considered an interesting target in DN research due to its therapeutic possibilities during diabetic disorders and renal protection.

Amelioration of Diabetic Nephropathy by Targeting Autophagy via Rapamycin or Fasting: Relation to Cell Apoptosis/Survival

Autophagy has been demonstrated to have a beneficial effect on diabetic nephropathy (DN). Rapamycin, an inhibitor of mTOR, was shown to stimulate β-cell autophagy. However, its effects on preventing or ameliorating DN is unclear, and its effects are worth studying. As fasting is now an attractive protective strategy, we aim to compare its effect to rapamycin effects on pancreatic and renal cells. Twenty-eight adult male Wistar Albino rats were randomly divided into four groups, using streptozotocin (STZ) to induce diabetes mellitus (DM). Autophagy was induced by two ways; rapamycin or fasting. The extent of autophagy and apoptosis were investigated by measuring the level of LC3B and p53 proteins, respectively, in pancreatic and kidney tissues using Western blotting (WB) technique and imaging the renal cells under transmission electron microscope. The efflux transporter P-glycoprotein was quantified by WB as well. Rapamycin-induced autophagy occurred concurrently with apoptosis. On the other hand, fasting supported P-glycoprotein recovery and renal cell survival together with disabling β-cells apoptosis. In conclusion, this study provides a potential link between rapamycin or fasting for the cross-regulation of apoptosis and autophagy in the setting of cell stress as DN. Unlike rapamycin, fasting enhanced the active expression of ABCB1 efflux protein, providing insights on the potential ameliorative effects of fasting in DN that require further elucidation.

Plant Polyphenols for Aging Health: Implication from Their Autophagy Modulating Properties in Age-Associated Diseases

Polyphenols are a family of naturally occurring organic compounds, majorly present in fruits, vegetables, and cereals, characterised by multiple phenol units, including flavonoids, tannic acid, and ellagitannin. Some well-known polyphenols include resveratrol, quercetin, curcumin, epigallocatechin gallate, catechin, hesperetin, cyanidin, procyanidin, caffeic acid, and genistein. They can modulate different pathways inside the host, thereby inducing various health benefits. Autophagy is a conserved process that maintains cellular homeostasis by clearing the damaged cellular components and balancing cellular survival and overall health. Polyphenols could maintain autophagic equilibrium, thereby providing various health benefits in mediating neuroprotection and exhibiting anticancer and antidiabetic properties. They could limit brain damage by dismantling misfolded proteins and dysfunctional mitochondria, thereby activating autophagy and eliciting neuroprotection. An anticarcinogenic mechanism is stimulated by modulating canonical and non-canonical signalling pathways. Polyphenols could also decrease insulin resistance and inhibit loss of pancreatic islet β-cell mass and function from inducing antidiabetic activity. Polyphenols are usually included in the diet and may not cause significant side effects that could be effectively used to prevent and treat major diseases and ailments.

Improving SIRT1 by trehalose supplementation reduces oxidative stress, inflammation, and histopathological scores in the kidney of aged rats

The aging process leads to progressive loss of kidney function. Sirtuin1 (SIRT1) exerts renoprotective effects by conferring resistance to cellular stresses. Trehalose potentially displayed various beneficial effects to promote health span. In this study, we investigated the effects of trehalose on renal SIRT1 and kidney function in senescent rats. Trehalose (2% w/v) was administrated in drinking water for 1 month to male aged rats (24 months). Then, the level of SIRT1 mRNA and protein, malondialdehyde, total antioxidant capacity, tumor necrosis factor α as well as parameters related to the function and histology of the kidneys were evaluated. Trehalose supplementation increased the level of SIRT1, whereas alleviated the level of oxidative stress, inflammation, and histopathology scores in senescent tissues. However, trehalose administration did not alter kidney function indices in old rats. Collectively, these findings suggested that trehalose was an effective intervention to ameliorate some aspects of age-associated injury in the old kidneys. PRACTICAL APPLICATIONS: Aging is associated with impairment in renal structure and function. Trehalose is a natural disaccharide, which is widely distributed in many organisms. The consumption of trehalose as a dietary supplement is increasing worldwide. This study showed that trehalose administration to aged rats had renoprotective effects through reducing oxidative stress and inflammation, which was mediated by SIRT1. Our results provide useful information for individuals using this sugar as a supplement.

CIDEC silencing attenuates diabetic nephropathy via inhibiting apoptosis and promoting autophagy

OBJECTIVE

The role of cell death-inducing DFF45-like effector C (CIDEC) in insulin resistance has been established, and it is considered to be an important trigger factor for the progression of diabetic nephropathy (DN). We intend to explore whether CIDEC plays an important role in the regulation of DN and its potential mechanism.

METHODS

High-fat diet and low dose streptozotocin were used to establish type 2 diabetic rat model. We investigate the role of CIDEC in the pathogenesis and process of DN through histopathological analysis, western blot and gene silencing. Meanwhile, the effect of CIDEC on renal tubular epithelial cells stimulated by high glucose was also verified.

RESULTS

DM group exhibited glucose and lipid metabolic disturbance, with hypertrophy of kidneys, damaged renal function, increased apoptosis, decreased autophagy, glomerulosclerosis and interstitial fibrosis. CIDEC gene silencing improved metabolic disorder and insulin resistance, alleviated renal hypertrophy and renal function damage, decreased glomerular and tubular apoptosis, increased autophagy and inhibited renal fibrosis. At the cellular level, high glucose stimulation increased CIDEC expression in renal tubular epithelial cells, accompanied by increased apoptosis and decreased autophagy. CIDEC gene silencing can improve autophagy and reduce apoptosis. At the molecular level, CIDEC gene silencing also decreased the expression of early growth response factor (EGR)1 and increased the expression of adipose triglyceride lipase (ATGL).

CONCLUSION

CIDEC gene silencing may delay the progression of DN by restoring autophagy activity and inhibiting apoptosis with the participation of EGR1and ATGL.

Prospective Pharmacological Potential of Resveratrol in Delaying Kidney Aging

Aging is an unavoidable part of life. The more aged we become, the more susceptible we become to various complications and damages to the vital organs, including the kidneys. The existing drugs for kidney diseases are mostly of synthetic origins; thus, natural compounds with minimal side-effects have attracted growing interest from the scientific community and pharmaceutical companies. A literature search was carried out to collect published research information on the effects of resveratrol on kidney aging. Recently, resveratrol has emerged as a potential anti-aging agent. This versatile polyphenol exerts its anti-aging effects by intervening in various pathologies and multi-signaling systems, including sirtuin type 1, AMP-activated protein kinase, and nuclear factor-κB. Researchers are trying to figure out the detailed mechanisms and possible resveratrol-mediated interventions in divergent pathways at the molecular level. This review highlights (i) the causative factors implicated in kidney aging and the therapeutic aspects of resveratrol, and (ii) the effectiveness of resveratrol in delaying the aging process of the kidney while minimizing all possible side effects.

Resveratrol and endoplasmic reticulum stress: A review of the potential protective mechanisms of the polyphenol

The endoplasmic reticulum (ER) is an organelle that performs a set of essential functions in cellular biology. These include synthesis of lipids, homeostasis of calcium, and controlling the folding of proteins. Inflammation and oxidative stress are two important reasons behind the accumulation of misfolded or unfolded proteins in the ER. In such circumstances, a series of measures are undertaken in the cell which are collectively called unfolded protein response (UPR). The aim of UPR is to reduce the burden of protein aggregates and promote survival. However, extended and unrestricted ER stress (ERS) can induce further inflammation and apoptosis. ERS and the UPR are involved in different diseases such as neurodegenerative and cardiovascular diseases. Resveratrol (RSV), a natural polyphenol, has well-documented evidence supporting its numerous biological properties including antioxidant, antiinflammatory, antiobesity, antidiabetic, and antiischemic activities. The compound is also known for its potential beneficial effects on cognitive function and liver, kidney, and lung health. In this review, the role of ERS in several pathological conditions and the potential protective effects of RSV are discussed. However, the scarcity of clinical data means that more research needs to be conducted to gain a lucid understanding of RSV's effects on endoplasmic reticulum stress (ERS) in humans.

SIRT1: Mechanism and Protective Effect in Diabetic Nephropathy

Diabetic nephropathy (DN) is referred to as the microvascular complication of the kidneys induced by insufficient production of insulin or an ineffective cellular response to insulin, and is the main cause of end-stage renal disease. Currently, available therapies provide only symptomatic relief and fail to improve the outcome of diabetic nephropathy. Studies on diabetic animals had shown overexpression of SIRT1 in both podocytes and renal tubular cells attenuated proteinuria and kidney injury in the animal model of DN. Sirt1 exerts renoprotective effects in DKD in part through the deacetylation of transcription factors involved in the disease pathogenesis, such as NF-кB, Smad3, FOXO and p53. The purpose of this review is to highlight the protective mechanism of SIRT1 involved in the pathogenesis of diabetic nephropathy.

An updated pharmacological insight of resveratrol in the treatment of diabetic nephropathy

As one of the most common complications of diabetes, nephropathy develops in approximately 40% of diabetic individuals. Although end stage kidney disease is known as one of the most consequences of diabetic nephropathy, the majority of diabetic individuals might die from cardiovascular diseases and infections before renal replacement treatment. Moreover, the routine medical treatments for diabetes hold undesirable side effects. The explosive prevalence of diabetes urges clinicians and scientists to investigate the complementary or alternative therapies. Phytochemicals are emerging as alternatives with a wide range of therapeutic effects on various pathologies, including diabetic kidney disease. Of those phytochemicals, resveratrol, a natural polyphenolic stilbene, has been found to exert a broad spectrum of health benefits via various signaling molecules. In particular, resveratrol has gained a great deal of attention because of its anti-oxidative, anti-inflammatory, anti-diabetic, anti-obesity, cardiovascular-protective, and anti-tumor properties. In the renal system, emerging evidence shows that resveratrol has already been used to ameliorate chronic or acute kidney injury. This review critically summarizes the current findings and molecular mechanisms of resveratrol in diabetic renal damage. In addition, we will discuss the adverse and inconsistent effects of resveratrol in diabetic nephropathy. Although there is increasing evidence that resveratrol affords great potential in diabetic nephropathy therapy, these results should be treated with caution before its clinical translation. In addition, the unfavorable pharmacokinetics and/or pharmacodynamics profiles, such as poor bioavailability, may limit its extensive clinical applications. It is clear that further research is needed to unravel these limitations and improve its efficacy against diabetic nephropathy. Increasing investigation of resveratrol in diabetic kidney disease will not only help us better understand its pharmacological actions, but also provide novel potential targets for therapeutic intervention.

The role of extracellular vesicles in podocyte autophagy in kidney disease

Podocytes are the key cells involved in protein filtration in the glomerulus. Once proteins appear in the urine when podocytes fail, patients will end with renal failure due to the progression of glomerular damage if no proper treatment is applied. The injury and loss of podocytes can be attributed to diverse factors, such as genetic, immunologic, toxic, or metabolic disorders. Recently, autophagy has emerged as a key mechanism to eliminate the unwanted cytoplasmic materials and to prolong the lifespan of podocytes by alleviating cell damage and stress. Typically, the fundamental function of extracellular vesicles (EVs) is to mediate the intercellular communication. Recent studies have suggested that, EVs, especially exosomes, play a certain role in information transfer by communicating proteins, mRNAs, and microRNAs with recipient cells. Under physiological and pathological conditions, EVs assist in the bioinformation interchange between kidneys and other organs. It is suggested that EVs are related to the pathogenesis of acute kidney injury and chronic kidney disease, including glomerular disease, diabetic nephropathy, renal fibrosis and end-stage renal disease. However, the role of EVs in podocyte autophagy remains unclear so far. Here, this study integrated the existing information about the relevancy, diagnostic value and therapeutic potential of EVs in a variety of podocytes-related diseases. The accumulating evidence highlighted that autophagy played a critical role in the homeostasis of podocytes in glomerular disease.

Dietary Polyphenols in Metabolic and Neurodegenerative Diseases: Molecular Targets in Autophagy and Biological Effects

Polyphenols represent a group of secondary metabolites of plants which have been analyzed as potent regulators of multiple biological processes, including cell proliferation, apoptosis, and autophagy, among others. These natural compounds exhibit beneficial effects and protection against inflammation, oxidative stress, and related injuries including metabolic diseases, such as cardiovascular damage, obesity and diabetes, and neurodegeneration. This review aims to summarize the mechanisms of action of polyphenols in relation to the activation of autophagy, stimulation of mitochondrial function and antioxidant defenses, attenuation of oxidative stress, and reduction in cell apoptosis, which may be responsible of the health promoting properties of these compounds.

Gypenoside inhibits ox-LDL uptake and foam cell formation through enhancing Sirt1-FOXO1 mediated autophagy flux restoration

BACKGROUND

Gypenoside (GP) is the major bioactive constituent of G. pentaphyllum, a traditional Chinese medicine. It has been reported that GP can affect autophagy and lipid metabolism in cultured cells. We hypothesize that GP can inhibit foam cell formation in cultured macrophages through autophagy modulation.

METHODS

THP1 cells were cultured and treated with oxidized low-density lipoprotein (ox-LDL), followed by GP treatment at different concentrations. The autophagy flux was evaluated using western blot and confocal microscope analyses. The ox-LDL uptake and foam cell formation abilities were measured.

RESULTS

We found that ox-LDL impaired the autophagy flux in the cultured macrophages, indicated by a significant reduction of LC3-II and autophagosome puncta quantification, as well as an accumulation of p62 proteins. GP treatment, however, dose-dependently restored the autophagy flux impaired by ox-LDL and reduced the ox-LDL uptake and foam cell transformation from THP1 cells, which can be alleviated, or exacerbated, by modulation of autophagy status using autophagy enhancer or inhibitor. Coimmunoprecipitation assays showed that GP up-regulated Srit1 and FOXO1 expression and enhanced their direct interaction, and thus contributed to the regulation of autophagy.

CONCLUSION

GP inhibits ox-LDL uptake and foam cell formation through enhancing Sirt1-FOXO1 mediated autophagy flux restoration, suggesting this compound has therapeutic potential for atherosclerosis.

Therapeutic application of nutraceuticals in diabetic nephropathy: Current evidence and future implications

Diabetes mellitus (DM) is a common metabolic disease which may cause several complications, such as diabetic nephropathy (DN). The routine medical treatments used for DM are not effective enough and have many undesirable side effects. Moreover, the global increased prevalence of DM makes researchers try to explore potential complementary or alternative treatments. Nutraceuticals, as natural products with pharmaceutical agents, have a wide range of therapeutic properties in various pathologic conditions such as DN. However, the exact underlying mechanisms have not been fully understood. The purpose of this review is to summarize recent findings on the effect of nutraceuticals on DN.

Health-promoting role of dietary bioactive compounds through epigenetic modulations: a novel prophylactic and therapeutic approach

The epigenome is an overall epigenetic state of an organism, which is as important as that of the genome for normal development and functioning of an individual. Epigenetics involves heritable but reversible changes in gene expression through alterations in DNA methylation, histone modifications and regulation of non-coding RNAs in cells, without any change in the DNA sequence. Epigenetic changes are owned by various environmental factors including pollution, microbiota and diet, which have profound effects on epigenetic modifiers. The bioactive compounds present in the diet mainly include curcumin, resveratrol, catechins, quercetin, genistein, sulforaphane, epigallocatechin-3-gallate, alkaloids, vitamins, and peptides. Bioactive compounds released during fermentation by the action of microbes also have a significant effect on the host epigenome. Besides, recent studies have explored the new insights in vitamin's functions through epigenetic regulation. These bioactive compounds exert synergistic, preventive and therapeutic effects when combined as well as when used with chemotherapeutic agents. Therefore, these compounds have potential of therapeutic agents that could be used as "Epidrug" to treat many inflammatory diseases and various cancers where chemotherapy results have many side effects. In this review, the effect of diet derived bioactive compounds through epigenetic modulations on in vitro and in vivo models is discussed.

Dysregulation of metabolic flexibility: The impact of mTOR on autophagy in neurodegenerative disease

Non-communicable diseases (NCDs) that involve neurodegenerative disorders and metabolic disease impact over 400 million individuals globally. Interestingly, metabolic disorders, such as diabetes mellitus, are significant risk factors for the development of neurodegenerative diseases. Given that current therapies for these NCDs address symptomatic care, new avenues of discovery are required to offer treatments that affect disease progression. Innovative strategies that fill this void involve the mechanistic target of rapamycin (mTOR) and its associated pathways of mTOR complex 1 (mTORC1), mTOR complex 2 (mTORC2), AMP activated protein kinase (AMPK), trophic factors that include erythropoietin (EPO), and the programmed cell death pathways of autophagy and apoptosis. These pathways are intriguing in their potential to provide effective care for metabolic and neurodegenerative disorders. Yet, future work is necessary to fully comprehend the entire breadth of the mTOR pathways that can effectively and safely translate treatments to clinical medicine without the development of unexpected clinical disabilities.

Accelerated Kidney Aging in Diabetes Mellitus

With aging, the kidney undergoes inexorable and progressive changes in structural and functional performance. These aging-related alterations are more obvious and serious in diabetes mellitus (DM). Renal accelerated aging under DM conditions is associated with multiple stresses such as accumulation of advanced glycation end products (AGEs), hypertension, oxidative stress, and inflammation. The main hallmarks of cellular senescence in diabetic kidneys include cyclin-dependent kinase inhibitors, telomere shortening, and diabetic nephropathy-associated secretory phenotype. Lysosome-dependent autophagy and antiaging proteins Klotho and Sirt1 play a fundamental role in the accelerated aging of kidneys in DM, among which the autophagy-lysosome system is the convergent mechanism of the multiple antiaging pathways involved in renal aging under DM conditions. Metformin and the inhibitor of sodium-glucose cotransporter 2 are recommended due to their antiaging effects independent of antihyperglycemia, besides angiotensin-converting enzyme inhibitors/angiotensin receptor blockers. Additionally, diet intervention including low protein and low AGEs with antioxidants are suggested for patients with diabetic nephropathy (DN). However, their long-term benefits still need further study. Exploring the interactive relationships among antiaging protein Klotho, Sirt1, and autophagy-lysosome system may provide insight into better satisfying the urgent medical needs of elderly patients with aging-related DN.

Sirtuins and their Biological Relevance in Aging and Age-Related Diseases

Sirtuins, initially described as histone deacetylases and gene silencers in yeast, are now known to have many more functions and to be much more abundant in living organisms. The increasing evidence of sirtuins in the field of ageing and age-related diseases indicates that they may provide novel targets for treating diseases associated with aging and perhaps extend human lifespan. Here, we summarize some of the recent discoveries in sirtuin biology that clearly implicate the functions of sirtuins in the regulation of aging and age-related diseases. Furthermore, human sirtuins are considered promising therapeutic targets for anti-aging and ageing-related diseases and have attracted interest in scientific communities to develop small molecule activators or drugs to ameliorate a wide range of ageing disorders. In this review, we also summarize the discovery and development status of sirtuin-targeted drug and further discuss the potential medical strategies of sirtuins in delaying aging and treating age-related diseases.

Resveratrol: Evidence for Its Nephroprotective Effect in Diabetic Nephropathy

Diabetic nephropathy (DN) is a severe complication of diabetes mellitus (DM). Dietary habits play a major role in determining the onset and progression of DM-related disorders and a proper diet (rich in fruits and vegetables) can delay or prevent the process of DM pathogenesis. Thus, increasing attention has been paid to polyphenols and polyphenol-rich foods since their increased intake has been associated with a reduced incidence of DM and its associated complications. Resveratrol is a polyphenolic phytoalexin that is mainly found in grapevines and berries. It is available in various pharmaceutical dosages and is widely recommended as a dietary supplement due to its beneficial effects. Remarkably, resveratrol's capability to effectively lower blood glucose levels without any side effects has been amply demonstrated in many in vitro and in vivo studies. Herein, we comprehensively review and discuss the nephroprotective effect of resveratrol during DN and its associated mechanisms. Resveratrol exerts its nephroprotective effects via various mechanisms including reducing oxidative stress and advanced glycation end-product (AGE) production, stimulating autophagy, inhibiting endoplasmic reticulum (ER) stress and inflammation, ameliorating lipotoxicity, activating the AMP kinase (AMPK) pathway, and modulating angiogenesis. Moreover, the use of resveratrol as an adjuvant to conventional antidiabetic therapies could be an effective approach to manage DN in humans. However, evidence is scarce to support whether resveratrol has beneficial effects in humans during DN. Therefore, clinical studies are warranted to elucidate resveratrol's role against DN.

Potential implications of polyphenols on aging considering oxidative stress, inflammation, autophagy, and gut microbiota

Naturally occurring compounds polyphenols are secondary metabolites of plants, comprised several categories, namely, flavonoids, phenolic acids, lignans and stilbenes. The biological aging process is driven by a series of interrelated mechanisms, including oxidative stress, inflammation status, and autophagy function, through diverse signaling pathways. Moreover, the crucial role of gut microbiota in regulating aging and health status was widely demonstrated. In recent years, the potential anti-aging benefits of polyphenols have been gaining increasing scientific interest due to their capability to modulate oxidative damage, inflammation, autophagy, and gut microbiota. This review highlights the influence of polyphenols in preventing aging disorders and augmenting lifespan based on the influence of oxidative stress, inflammation, autophagy, and gut microbiota, and encourages research on novel polyphenol-based strategies and clinical trials to develop a nutrition-oriented holistic anti-aging therapy.

New Insights for nicotinamide: Metabolic disease, autophagy, and mTOR

Metabolic disorders, such as diabetes mellitus (DM), are increasingly becoming significant risk factors for the health of the global population and consume substantial portions of the gross domestic product of all nations. Although conventional therapies that include early diagnosis, nutritional modification of diet, and pharmacological treatments may limit disease progression, tight serum glucose control cannot prevent the onset of future disease complications. With these concerns, novel strategies for the treatment of metabolic disorders that involve the vitamin nicotinamide, the mechanistic target of rapamycin (mTOR), mTOR Complex 1 (mTORC1), mTOR Complex 2 (mTORC2), AMP activated protein kinase (AMPK), and the cellular pathways of autophagy and apoptosis offer exceptional promise to provide new avenues of treatment. Oversight of these pathways can promote cellular energy homeostasis, maintain mitochondrial function, improve glucose utilization, and preserve pancreatic beta-cell function. Yet, the interplay among mTOR, AMPK, and autophagy pathways can be complex and affect desired clinical outcomes, necessitating further investigations to provide efficacious treatment strategies for metabolic dysfunction and DM.

Effects of a Red Orange and Lemon Extract in Obese Diabetic Zucker Rats: Role of Nicotinamide Adenine Dinucleotide Phosphate Oxidase

Diabetic nephropathy (DN) is the primary cause of end-stage renal disease, worldwide, and oxidative stress has been recognized as a key factor in the pathogenesis and progression of DN. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase has the most important contribution to reactive oxygen species generation during the development of DN. Bioactive compound use has emerged as a potential approach to reduce chronic renal failure. Therefore, a red orange and lemon extract (RLE) rich in anthocyanins was chosen in our study, to reduce the toxic renal effects during the development of DN in Zucker diabetic fatty rat (ZDF). RLE effects were examined daily for 24 weeks, through gavage, in ZDF rats treated with RLE (90 mg/kg). At the end of the experiment, ZDF rats treated with RLE showed a reduction of the diabetes-associated up-regulation of both NOX4 and the p47-phox and p22-phox subunits, and restored the BAX/BCL-2 ratio respect to ZDF rats. Furthermore, RLE was able to reduce the oxidative DNA damage measured in urine samples in ZDF rats. This study showed that RLE could prevent the renal damage induced by DN through its capacity to inhibit NOX4 and apoptosis mechanisms.

Hypoxia-inducible factor-1α: A promising therapeutic target for vasculopathy in diabetic retinopathy

Diabetic retinopathy (DR) is a serious condition that can cause blindness in diabetic patients. It is a neurovascular disease, but the pathogenesis leading to the onset of this disease is still not completely understood. However, hypoxia with subsequent neovascularization is a characteristic phenomenon observed with DR. Cellular response to hypoxia is mediated by the transcriptional regulator hypoxia-inducible factor (HIF). Long-term research has shown that one isotype of HIF, HIF-1α, may play a pivotal role under hypoxic conditions, and an increasing number of studies have shown that HIF-1α and its target genes contribute to retinal neovascularization. Therefore, targeting HIF-1α may lead to more effective DR treatments. This review describes the possible mechanisms of HIF-1α in neovascularization of DR. Furthermore, various inhibitors of HIF-1α that may have viable potential in the treatment of DR are also discussed.

Apigenin Prevents Acetaminophen-Induced Liver Injury by Activating the SIRT1 Pathway

Acetaminophen (APAP) overdose is the main cause of acute liver failure. Apigenin (API) is a natural dietary flavonol with high antioxidant capacity. Herein, we investigated protection by API against APAP-induced liver injury in mice, and explored the potential mechanism. Cell viability assays and mice were used to evaluate the effects of API against APAP-induced liver injury. Western blotting, immunofluorescence staining, RT-PCR, and Transmission Electron Microscope were carried out to determine the signalling pathways affected by API. Analysis of mouse serum levels of alanine/aspartate aminotransferase (ALT/AST), malondialdehyde (MDA), liver myeloperoxidase (MPO) activity, glutathione (GSH), and reactive oxygen species (ROS) revealed that API (80 mg/kg) owned protective effect on APAP-induced liver injury. Meanwhile, API ameliorated the decreased cell viability in L-02 cells incubated by APAP with a dose dependent. Furthermore, API promoted SIRT1 expression and deacetylated p53. Western blotting showed that API promoted APAP-induced autophagy, activated the NRF2 pathway, and inhibited the transcriptional activation of nuclear p65 in the presence of APAP. Furthermore, SIRT1 inhibitor EX-527 reduced protection by API against APAP-induced hepatotoxicity. Molecular docking results indicate potential interaction between API and SIRT1. API prevents APAP-induced liver injury by regulating the SIRT1-p53 axis, thereby promoting APAP-induced autophagy and ameliorating APAP-induced inflammatory responses and oxidative stress injury.

Cocoa ameliorates renal injury in Zucker diabetic fatty rats by preventing oxidative stress, apoptosis and inactivation of autophagy

Redox balance, autophagy and apoptosis are main processes involved in the development of diabetic nephropathy. Epidemiological and animal studies suggest that cocoa might reduce the risk of diabetic complications. However, the molecular mechanisms responsible for these potential preventive activities and whether cocoa exerts beneficial effects on dysregulated signalling pathways involved in cellular antioxidant defence, autophagy and apoptosis in the diabetic kidney remain largely unknown. Therefore, this work investigated the effect of a cocoa-rich diet on the mentioned processes in the renal cortex of Zucker Diabetic Fatty (ZDF) rats. Male ZDF rats were fed either a control or cocoa-rich diet (10%), and Zucker lean animals received the control diet (10-20 weeks-of-life). ZDF rats fed with cocoa decreased body weight and glucose and insulin levels, and improved renal function. Cocoa intake further prevented the enhanced renal cortical oxidative stress in diabetic rats by regulating the antioxidant defence system and close-related proteins to cytoprotection and cell response; thus, cocoa diminished oxidative markers (reactive oxygen species and carbonyl groups) and NADPH-oxidase-4 levels, and restored key enzymatic antioxidant activities (superoxide dismutase and catalase), nuclear-erythroid-2-related factor-2, and ERK-MAPK levels, as well as sirtuin-1/5'-AMP-activated-protein kinase signalling. Moreover, in ZDF rats cocoa-rich diet contributed to alleviation of the renal cortical injury through autophagy activation (p62 upregulation, and downregulation of beclin-1 and LC3), and inhibition of apoptosis (Bcl-xL stimulation and suppression of Bax and caspases-9 and -3). These findings provide the first in vivo evidence on the molecular mechanisms of cocoa to circumvent renal cortical damage that involve improvement of antioxidant competences, stimulation of autophagy and suppression of apoptosis in ZDF rats.

Role of Impaired Nutrient and Oxygen Deprivation Signaling and Deficient Autophagic Flux in Diabetic CKD Development: Implications for Understanding the Effects of Sodium-Glucose Cotransporter 2-Inhibitors

Growing evidence indicates that oxidative and endoplasmic reticular stress, which trigger changes in ion channels and inflammatory pathways that may undermine cellular homeostasis and survival, are critical determinants of injury in the diabetic kidney. Cells are normally able to mitigate these cellular stresses by maintaining high levels of autophagy, an intracellular lysosome-dependent degradative pathway that clears the cytoplasm of dysfunctional organelles. However, the capacity for autophagy in both podocytes and renal tubular cells is markedly impaired in type 2 diabetes, and this deficiency contributes importantly to the intensity of renal injury. The primary drivers of autophagy in states of nutrient and oxygen deprivation-sirtuin-1 (SIRT1), AMP-activated protein kinase (AMPK), and hypoxia-inducible factors (HIF-1α and HIF-2α)-can exert renoprotective effects by promoting autophagic flux and by exerting direct effects on sodium transport and inflammasome activation. Type 2 diabetes is characterized by marked suppression of SIRT1 and AMPK, leading to a diminution in autophagic flux in glomerular podocytes and renal tubules and markedly increasing their susceptibility to renal injury. Importantly, because insulin acts to depress autophagic flux, these derangements in nutrient deprivation signaling are not ameliorated by antihyperglycemic drugs that enhance insulin secretion or signaling. Metformin is an established AMPK agonist that can promote autophagy, but its effects on the course of CKD have been demonstrated only in the experimental setting. In contrast, the effects of sodium-glucose cotransporter-2 (SGLT2) inhibitors may be related primarily to enhanced SIRT1 and HIF-2α signaling; this can explain the effects of SGLT2 inhibitors to promote ketonemia and erythrocytosis and potentially underlies their actions to increase autophagy and mute inflammation in the diabetic kidney. These distinctions may contribute importantly to the consistent benefit of SGLT2 inhibitors to slow the deterioration in glomerular function and reduce the risk of ESKD in large-scale randomized clinical trials of patients with type 2 diabetes.

Mechanisms of Herbal Nephroprotection in diabetes mellitus

Diabetic nephropathy (DN) is a leading cause of kidney morbidity. Despite the multilayered complexity of the mechanisms involved in the pathogenesis of DN, the conventional treatment is limited to just a few drug classes fraught with the risk of adverse events, including the progression of renal dysfunction. Phytoceuticals offer a promising alternative as they act on the many-sidedness of DN pathophysiology, multitargeting its intricacies. This paper offers a review of the mechanisms underlying the protective action of these phytoagents, including boosting the antioxidant capabilities, suppression of inflammation, averting the proliferative and sclerosing/fibrosing events. The pathogenesis of DN is viewed as a continuum going from the original offense, high glucose, through the noxious products it generates (advanced glycation end-products, products of oxidative and nitrosative stress) and the signaling chains consequently brought into action, to the harmful mediators of inflammation, sclerosis, and proliferation that eventually lead to DN, despite the countervailing attempts of the protective mechanisms. Special attention was given to the various pathways involved, pointing out the ability of the phytoagents to hinder the deleterious ones (especially those leading to, driven by, or associated with TGF-β activation, SREBP, Smad, MAPK, PKC, NF-κB, NLRP3 inflammasome, and caspase), to promote the protective ones (PPAR-α, PPAR-γ, EP4/Gs/AC/cAMP, Nrf2, AMPK, and SIRT1), and to favorably modulate those with potentially dual effect (PI3K/Akt). Many phytomedicines have emerged as potentially useful out of in vitro and in vivo studies, but the scarcity of human trials seriously undermines their usage in the current clinical practice-an issue that stringently needs to be addressed.

Effect of atorvastatin on Aβ1-42 -induced alteration of SESN2, SIRT1, LC3II and TPP1 protein expressions in neuronal cell cultures

OBJECTIVES

Sestrins (SESNs) and sirtuins (SIRTs) are antioxidant and antiapoptotic genes and crucial mediators for lysosomal autophagy regulation that play a pivotal role in the Alzheimer's disease (AD). Recently, statins have been linked to the reduced prevalence of AD in statin-prescribed populations yet molecular basis for the neuroprotective action of statins is still under debate.

METHODS

This study was undertaken whether Aβ-induced changes of SESN2 and SIRT1 protein expression, autophagy marker LC3II and lysosomal enzyme TPP1 affected by atorvastatin (Western blot) and its possible role in Aβ neurotoxicity (ELISA).

KEY FINDINGS/RESULTS

We showed that SESN2 and LC3II expressions were elevated, whereas SIRT1 and TPP1 expressions were decreased in the Aβ_1-42 -exposed human neuroblastoma cells (SH-SY5Y). Co-administration of atorvastatin with Aβ_1-42 compensates SESN2 increase and recovers SIRT1 decline by reducing oxidative stress, decreasing SESN2 expression and increasing SIRT1 expression by its neuroprotective action. Atorvastatin induced LC3II but not TPP1 level in the Aβ_1-42 -exposed cells suggested that atorvastatin is effective in the formation of autophagosome but not on the expression of the specific lysosomal enzyme TPP1.

DISCUSSION AND CONCLUSION

Together, these results indicate that atorvastatin induced SESN2, SIRT1 and LC3II levels play a protective role against Aβ_1-42 neurotoxicity.

Health Benefits of Resveratrol in Kidney Disease: Evidence from In Vitro and In Vivo Studies

Different diseases and disorders that affect the kidneys include, but are not limited to, glomerulonephritis, diabetic nephropathy, polycystic kidney disease, kidney stones, renal fibrosis, sepsis, and renal cell carcinoma. Kidney disease tends to develop over many years, making it difficult to identify until much later when kidney function is severely impaired and undergoing kidney failure. Although conservative care, symptom management, medication, dialysis, transplantation, and aggressive renal cancer therapy are some of the current strategies/approaches to kidney disease treatment, new preventative targeted therapies are needed. Epidemiological studies have suggested that a diet rich in fruits and vegetables is associated with health benefits including protection against kidney disease and renal cancer. Resveratrol, a polyphenol found in grapes and berries, has been reported to have antioxidant, anti-inflammatory, antidiabetic, hepatoprotective, neuroprotective, and anti-cancer properties. The current review summarizes the existing in vitro and in vivo animal and human studies examining the nephroprotective effects of resveratrol.