5'-Monophosphate-activated protein kinase (AMPK) improves autophagic activity in diabetes and diabetic complications

The mechanisms underlying Chinese medicines to treat inflammation in diabetic kidney disease

ETHNIC PHARMACOLOGICAL RELEVANCE

Diabetic kidney disease (DKD) is the main cause of end-stage renal disease (ESRD), which is a public health problem with a significant economic burden. Serious adverse effects, such as hypotension, hyperkalemia, and genitourinary infections, as well as increasing adverse cardiovascular events, limit the clinical application of available drugs. Plenty of randomized controlled trials(RCTs), meta-analysis(MAs) and systematic reviews(SRs) have demonstrated that many therapies that have been used for a long time in medical practice including Chinese patent medicines(CPMs), Chinese medicine prescriptions, and extracts are effective in alleviating DKD, but the mechanisms by which they work are still unknown. Currently, targeting inflammation is a central strategy in DKD drug development. In addition, many experimental studies have identified many Chinese medicine prescriptions, medicinal herbs and extracts that have the potential to alleviate DKD. And part of the mechanisms by which they work have been uncovered.

AIM OF THIS REVIEW

This review aims to summarize therapies that have been proven effective by RCTs, MAs and SRs, including CPMs, Chinese medicine prescriptions, and extracts. This review also focuses on the efficiency and potential targets of Chinese medicine prescriptions, medicinal herbs and extracts discovered in experimental studies in improving immune inflammation in DKD.

METHODS

We searched for relevant scientific articles in the following databases: PubMed, Google Scholar, and Web of Science. We summarized effective CPMs, Chinese medicine prescriptions, and extracts from RCTs, MAs and SRs. We elaborated the signaling pathways and molecular mechanisms by which Chinese medicine prescriptions, medicinal herbs and extracts alleviate inflammation in DKD according to different experimental studies.

RESULTS

After overviewing plenty of RCTs with the low hierarchy of evidence and MAs and SRs with strong heterogeneity, we still found that CPMs, Chinese medicine prescriptions, and extracts exerted promising protective effects against DKD. However, there is insufficient evidence to prove the safety of Chinese medicines. As for experimental studies, Experiments in vitro and in vivo jointly demonstrated the efficacy of Chinese medicines(Chinese medicine prescriptions, medicinal herbs and extracts) in DKD treatment. Chinese medicines were able to regulate signaling pathways to improve inflammation in DKD, such as toll-like receptors, NLRP3 inflammasome, Nrf2 signaling pathway, AMPK signaling pathway, MAPK signaling pathway, JAK-STAT, and AGE/RAGE.

CONCLUSION

Chinese medicines (Chinese medicine prescriptions, medicinal herbs and extracts) can improve inflammation in DKD. For drugs that are effective in RCTs, the underlying bioactive components or extracts should be identified and isolated. Attention should be given to their safety and pharmacokinetics. Acute, subacute, and subchronic toxicity studies should be designed to determine the magnitude and tolerability of side effects in humans or animals. For drugs that have been proven effective in experimental studies, RCTs should be designed to provide reliable evidence for clinical translation. In a word, Chinese medicines targeting immune inflammation in DKD are a promising direction.

Corilagin alleviates podocyte injury in diabetic nephropathy by regulating autophagy via the SIRT1-AMPK pathway

BACKGROUND

Diabetic nephropathy (DN) is the most frequent chronic microvascular consequence of diabetes, and podocyte injury and malfunction are closely related to the development of DN. Studies have shown that corilagin (Cor) has hepatoprotective, anti-inflammatory, antibacterial, antioxidant, anti-hypertensive, anti-diabetic, and anti-tumor activities.

AIM

To explore the protective effect of Cor against podocyte injury in DN mice and the underlying mechanisms.

METHODS

Streptozotocin and a high-fat diet were combined to generate DN mice models, which were then divided into either a Cor group or a DN group (n = 8 in each group). Mice in the Cor group were intraperitoneally injected with Cor (30 mg/kg/d) for 12 wk, and mice in the DN group were treated with saline. Biochemical analysis was used to measure the blood lipid profiles. Hematoxylin and eosin staining was used to detect pathological changes in kidney tissue. Immunohistochemistry and Western blotting were used to assess the protein expression of nephrin and podocin. Mouse podocyte cells (MPC5) were cultured and treated with glucose (5 mmol/L), Cor (50 μM), high glucose (HG) (30 mmol/L), and HG (30 mmol/L) plus Cor (50 μM). Real-time quantitative PCR and Western blotting were performed to examine the effects of Cor on podocyte autophagy.

RESULTS

Compared with the control group, the DN mice models had increased fasting blood glucose, glycosylated hemoglobin, triglycerides, and total cholesterol, decreased nephrin and podocin expression, increased apoptosis rate, elevated inflammatory cytokines, and enhanced oxidative stress. All of the conditions mentioned above were alleviated after intervention with Cor. In addition, Cor therapy improved SIRT1 and AMPK expression (P < 0.001), inhibited reactive oxygen species and oxidative stress, and elevated autophagy in HG-induced podocytes (P < 0.01).

CONCLUSION

Cor alleviates podocyte injury by regulating autophagy via the SIRT1-AMPK pathway, thereby exerting its protective impact on renal function in DN mice.

Regulation of Autophagy Signaling Pathways by Ginseng Saponins: A Review

Ginseng saponins (ginsenosides), bioactive compounds derived from ginseng, are widely used natural products with potent therapeutic properties in the management of various ailments, particularly tumors, cardiovascular and cerebrovascular diseases, and immune system disorders. Autophagy, a highly regulated and multistep process involving the breakdown of impaired organelles and macromolecules by autophagolysosomes and autophagy-related genes (ATGs), has gained increasing attention as a potential target for ginsenoside-mediated disease treatment. This review aims to provide a comprehensive overview of recent research advances in the understanding of autophagy-related signaling pathways and the role of ginsenoside-mediated autophagy regulation. By delving into the intricate autophagy signaling pathways underpinning the pharmacological properties of ginsenosides, we highlight their therapeutic potential in addressing various conditions. Our findings serve as a comprehensive reference for further investigation into the medicinal properties of ginseng or ginseng-related products.

AMPK pathway: an emerging target to control diabetes mellitus and its related complications

Purpose

In this extensive review work, the important role of AMP-activated protein kinase (AMPK) in causing of diabetes mellitus has been highlighted. Structural feature of AMPK as well its regulations and roles are described nicely, and the association of AMPK with the diabetic complications like nephropathy, neuropathy and retinopathy are also explained along with the connection between AMPK and β-cell function, insulin resistivity, mTOR, protein metabolism, autophagy and mitophagy and effect on protein and lipid metabolism.

Methods

Published journals were searched on the database like PubMed, Medline, Scopus and Web of Science by using keywords such as AMPK, diabetes mellitus, regulation of AMPK, complications of diabetes mellitus, autophagy, apoptosis etc.

Result

After extensive review, it has been found that, kinase enzyme like AMPK is having vital role in management of type II diabetes mellitus. AMPK involve in enhance the concentration of glucose transporter like GLUT 1 and GLUT 4 which result in lowering of blood glucose level in influx of blood glucose into the cells; AMPK increases the insulin sensitivity and decreases the insulin resistance and further AMPK decreases the apoptosis of β-cells which result into secretion of insulin and AMPK is also involve in declining of oxidative stress, lipotoxicity and inflammation, owing to which organ damage due to diabetes mellitus can be lowered by activation of AMPK.

Conclusion

As AMPK activation leads to overall control of diabetes mellitus, designing and developing of small molecules or peptide that can act as AMPK agonist will be highly beneficial for control or manage diabetes mellitus.

Autophagy and mitophagy as potential therapeutic targets in diabetic heart condition: Harnessing the power of nanotheranostics

Autophagy and mitophagy pose unresolved challenges in understanding the pathology of diabetic heart condition (DHC), which encompasses a complex range of cardiovascular issues linked to diabetes and associated cardiomyopathies. Despite significant progress in reducing mortality rates from cardiovascular diseases (CVDs), heart failure remains a major cause of increased morbidity among diabetic patients. These cellular processes are essential for maintaining cellular balance and removing damaged or dysfunctional components, and their involvement in the development of diabetic heart disease makes them attractive targets for diagnosis and treatment. While a variety of conventional diagnostic and therapeutic strategies are available, DHC continues to present a significant challenge. Point-of-care diagnostics, supported by nanobiosensing techniques, offer a promising alternative for these complex scenarios. Although conventional medications have been widely used in DHC patients, they raise several concerns regarding various physiological aspects. Modern medicine places great emphasis on the application of nanotechnology to target autophagy and mitophagy in DHC, offering a promising approach to deliver drugs beyond the limitations of traditional therapies. This article aims to explore the potential connections between autophagy, mitophagy and DHC, while also discussing the promise of nanotechnology-based theranostic interventions that specifically target these molecular pathways.

The role of AMPK in macrophage metabolism, function and polarisation

AMP-activated protein kinase (AMPK) is a ubiquitous sensor of energy and nutritional status in eukaryotic cells. It plays a key role in regulating cellular energy homeostasis and multiple aspects of cell metabolism. During macrophage polarisation, AMPK not only guides the metabolic programming of macrophages, but also counter-regulates the inflammatory function of macrophages and promotes their polarisation toward the anti-inflammatory phenotype. AMPK is located at the intersection of macrophage metabolism and inflammation. The metabolic characteristics of macrophages are closely related to immune-related diseases, infectious diseases, cancer progression and immunotherapy. This review discusses the structure of AMPK and its role in the metabolism, function and polarisation of macrophages. In addition, it summarises the important role of the AMPK pathway and AMPK activators in the development of macrophage-related diseases.

The novel GLP-1/GIP dual agonist DA3-CH improves rat type 2 diabetes through activating AMPK/ACC signaling pathway

BACKGROUND

Type 2 diabetes mellitus (T2DM) accounts for more than 95% of all diabetes. DA3-CH is a novel dual receptor agonist of glucagon like peptide-1 (GLP-1) and glucose dependent insulin stimulating polypeptide (GIP). The regulatory role of DA3-CH in T2DM has not been reported.

METHODS

T2DM rat model was established successfully with high sugar and fat feed and streptomycin (STZ) induction. The mRNA and protein expression were measured with RT-PCR and western blotting. The apoptosis level in the pancreatic tissue was evaluated with Tunel staining. Blood glucose, fat, and oxidative stress indicators were measured.

RESULTS

DA3-CH greatly improved T2DM symptoms by reducing blood glucose, blood fat, pancreatic tissue injury, apoptosis, and oxidative stress condition. The inactivation of Adenylate activated protein kinase (AMPK)/acetyl CoA carboxylase (ACC) signaling pathway in T2DM rats was promoted by DA3-CH. The influence of DA3-CH was significantly reversed by Com-C, the inhibitor of AMPK/ACC signaling pathway.

CONCLUSIONS

DA3-CH might improve T2DM through targeting AMPK/ACC signaling pathway. This study might provide a novel therapeutic strategy for the prevention and treatment of T2DM through targeting DA3-CH and AMPK/ACC signaling pathway.

Cordycepin inhibits ERK pathway to suppress FGF9-induced tumorigenesis with MA-10 mouse Leydig tumor cells

Fibroblast growth factor 9 (FGF9) is a member of FGF family, and abnormal expression of FGF9 can promote tumorigenesis. Cordycepin, a major bioactive component in fungus Cordyceps sinensis, could suppress various tumors. We have shown that cordycepin could inhibit FGF9-induced testicular tumor growth in vitro and in vivo with MA-10 mouse Leydig tumor cells. In the present study, the mechanisms related to apoptosis and autophagy were determined. Results show that cordycepin significantly suppressed cell viability and colony formation with correlatedly morphological change related to cell death in FGF9-treated MA-10 cells. Flow cytometry and western blotting results further demonstrate that cordycepin induced apoptosis through the cleavage of caspase-8, -9, -3 and PARP in FGF9-treated MA-10 cells. However, the expressions of LC3-II, beclin-1 and p62 were not stimulated by cordycepin with the presence of FGF9, suggesting cordycepin would activate apoptosis, but not autophagy, in FGF9-treated MA-10 cells. Moreover, inhibition of ERK signal pathway and autophagy would enhance cordycepin-induced cell death effects in FGF9-treated MA-10 cells, referring that ERK signaling was regulated under cordycepin and FGF9 treatments. In NOD-SCID mouse allograft model inoculated with MA-10 cells, cordycepin significantly suppressed tumor growth with the presence of FGF9, and the cleavage of caspase-3 could be observed in tumor tissue, implying cordycepin induced caspase cascade to suppress tumor growth. Moreover, cordycepin plus U0126, ERK inhibitor, further significantly suppressed tumor growth with the presence of FGF9 as compared to the FGF9 only group, confirming the involvement of ERK signaling in this event. In conclusion, cordycepin induced caspase and ERK pathways to promote MA-10 cell apoptosis, but not autophagy, with the presence of FGF9.

Metformin attenuates symptoms of osteoarthritis: role of genetic diversity of Bcl2 and CXCL16 in OA

OBJECTIVE

This study aimed to evaluate the effectiveness of metformin versus placebo in overweight patients with knee osteoarthritis (OA). In addition, to assess the effects of inflammatory mediators and apoptotic proteins in the pathogenesis of OA, the genetic polymorphisms of two genes, one related to apoptosis (rs2279115 of Bcl-2) and the other related to inflammation (rs2277680 of CXCL-16), were investigated.

METHODS

In this double-blind placebo-controlled clinical trial, patients were randomly divided to two groups, one group receiving metformin (n = 44) and the other one receiving an identical inert placebo (n = 44) for 4 consecutive months (starting dose 0.5 g/day for the first week, increase to 1 g/day for the second week, and further increase to 1.5 g/day for the remaining period). Another group of healthy individuals (n = 92) with no history and diagnosis of OA were included in this study in order to evaluate the role of genetics in OA. The outcome of treatment regimen was evaluated using the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire. The frequency of variants of rs2277680 (A181V) and rs2279115 (938C>A) were determined in extracted DNAs using PCR-RFLP method.

RESULTS

Our results indicated an increase in scores of pain (P ≤ 0.0001), activity of daily living (ADL) (P ≤ 0.0001), sport and recreation (Sport/Rec) (P ≤ 0.0001), and quality of life (QOL) (P = 0.003) and total scores of the KOOS questionnaire in the metformin group compared to the placebo group. Susceptibility to OA was associated with age, gender, family history, CC genotype of 938C>A (Pa = 0.001; OR = 5.2; 95% CI = 2.0-13.7), and GG+GA genotypes of A181V (Pa = 0.04; OR = 2.1; 95% CI = 1.1-10.5). The C allele of 938C>A (Pa = 0.04; OR = 2.2; 95% CI = 1.1-9.8) and G allele of A181V (Pa = 0.02; OR = 2.2; 95% CI = 1.1-4.8) were also associated with OA.

CONCLUSION

Our findings support the possible beneficial effects of metformin on improving pain, ADL, Sport/Rec, and QOL in OA patients. Our findings support the association between the CC genotype of Bcl-2 and GG+GA genotypes of CXCL-16 and OA.

The high-intensity interval training (HIIT) and curcumin supplementation can positively regulate the autophagy pathway in myocardial cells of STZ-induced diabetic rats

OBJECTIVE

Targeting autophagy is a new therapeutic strategy for the complications of diabetes,such as diabetic cardiomyopathy (DCM). During diabetes, increased or insufficient autophagic activity causes aberrations in cellular homeostasis. Regarding the conflicting and unclear results regarding the effect of HIIT and curcumin supplementation on the expression of genes associated to autophagy, this study aimed to assess whether 4-week high-intensity interval training (HIIT) and curcumin supplementation are able to influence the expression of autophagy-related genes in myocardial cells of diabetic rats.

METHODS

In an experimental design, 24 male Wistar rats were randomly divided into 4 groups: non-diabetic control (NC), diabetic control (DC), diabetes + HIIT (D + HIIT), and diabetes + curcumin (D + CU). After HIIT program and curcumin treatment, the genes expression of autophagy pathway were assessed in the myocardium by real-time PCR Tanique.

RESULTS

The results indicated that the expression levels of ATG1, Beclin1, ATG5, and LAMP-2 genes were significantly reduced in the DC group compared to the NC group (p < 0.001). Following 4-week HIIT, the expression of Beclin1, ATG-5, and LAMP-2 improved considerably compared to the DC group (p < 0.001, p < 0.001, and p < 0.05, respectively). In addition, after 4 weeks of curcumin supplementation, the expression levels of ATG-5 and Beclin-1 were significantly improved compared to the DC group (p < 0.001, p < 0.05, respectively). It seems HIIT and curcumin supplementation can be an effective approach for inducing autophagy and improving cardiac function in DCM rats.However, HIIT seems more effective than curcumin in this regard.

PKM2-mediated neuronal hyperglycolysis enhances the risk of Parkinson's disease in diabetic rats

Epidemiological and animal studies indicate that pre-existing diabetes increases the risk of Parkinson's disease (PD). However, the mechanisms underlying this association remain unclear. In the present study, we found that high glucose (HG) levels in the cerebrospinal fluid (CSF) of diabetic rats might enhance the effect of a subthreshold dose of the neurotoxin 6-hydroxydopamine (6-OHDA) on the development of motor disorders, and the damage to the nigrostriatal dopaminergic neuronal pathway. In vitro, HG promoted the 6-OHDA-induced apoptosis in PC12 cells differentiated to neurons with nerve growth factor (NGF) (NGF-PC12). Metabolomics showed that HG promoted hyperglycolysis in neurons and impaired tricarboxylic acid cycle (TCA cycle) activity, which was closely related to abnormal mitochondrial fusion, thus resulting in mitochondrial loss. Interestingly, HG-induced upregulation of pyruvate kinase M2 (PKM2) combined with 6-OHDA exposure not only mediated glycolysis but also promoted abnormal mitochondrial fusion by upregulating the expression of MFN2 in NGF-PC12 cells. In addition, we found that PKM2 knockdown rescued the abnormal mitochondrial fusion and cell apoptosis induced by HG+6-OHDA. Furthermore, we found that shikonin (SK), an inhibitor of PKM2, restored the mitochondrial number, promoted TCA cycle activity, reversed hyperglycolysis, enhanced the tolerance of cultured neurons to 6-OHDA, and reduced the risk of PD in diabetic rats. Overall, our results indicate that diabetes promotes hyperglycolysis and abnormal mitochondrial fusion in neurons through the upregulation of PKM2, leading to an increase in the vulnerability of dopaminergic neurons to 6-OHDA. Thus, the inhibition of PKM2 and restoration of mitochondrial metabolic homeostasis/pathways may prevent the occurrence and development of diabetic PD.

Altered glucose metabolism in Alzheimer's disease: Role of mitochondrial dysfunction and oxidative stress

Increasing evidence suggests that abnormal cerebral glucose metabolism is largely present in Alzheimer's disease (AD). The brain utilizes glucose as its main energy source and a decline in its metabolism directly reflects on brain function. Weighing on recent evidence, here we systematically assessed the aberrant glucose metabolism associated with amyloid beta and phosphorylated tau accumulation in AD brain. Interlink between insulin signaling and AD highlighted the involvement of the IRS/PI3K/Akt/AMPK signaling, and GLUTs in the disease progression. While shedding light on the mitochondrial dysfunction in the defective glucose metabolism, we further assessed functional consequences of AGEs (advanced glycation end products) accumulation, polyol activation, and other contributing factors including terminal respiration, ROS (reactive oxygen species), mitochondrial permeability, PINK1/parkin defects, lysosome-mitochondrial crosstalk, and autophagy/mitophagy. Combined with the classic plaque and tangle pathologies, glucose hypometabolism with acquired insulin resistance and mitochondrial dysfunction potentiate these factors to exacerbate AD pathology. To this end, we further reviewed AD and DM (diabetes mellitus) crosstalk in disease progression. Taken together, the present work discusses the emerging role of altered glucose metabolism, contributing impact of insulin signaling, and mitochondrial dysfunction in the defective cerebral glucose utilization in AD.

cPKCγ Deficiency Exacerbates Autophagy Impairment and Hyperphosphorylated Tau Buildup through the AMPK/mTOR Pathway in Mice with Type 1 Diabetes Mellitus

Type 1 diabetes mellitus (T1DM)-induced cognitive dysfunction is common, but its underlying mechanisms are still poorly understood. In this study, we found that knockout of conventional protein kinase C (cPKC)γ significantly increased the phosphorylation of Tau at Ser214 and neurofibrillary tangles, but did not affect the activities of GSK-3β and PP2A in the hippocampal neurons of T1DM mice. cPKCγ deficiency significantly decreased the level of autophagy in the hippocampal neurons of T1DM mice. Activation of autophagy greatly alleviated the cognitive impairment induced by cPKCγ deficiency in T1DM mice. Moreover, cPKCγ deficiency reduced the AMPK phosphorylation levels and increased the phosphorylation levels of mTOR in vivo and in vitro. The high glucose-induced Tau phosphorylation at Ser214 was further increased by the autophagy inhibitor and was significantly decreased by an mTOR inhibitor. In conclusion, these results indicated that cPKCγ promotes autophagy through the AMPK/mTOR signaling pathway, thus reducing the level of phosphorylated Tau at Ser214 and neurofibrillary tangles.

Perspectives for Forkhead box transcription factors in diabetic cardiomyopathy: Their therapeutic potential and possible effects of salvianolic acids

Diabetic cardiomyopathy (DCM) is the primary cause of morbidity and mortality in diabetic cardiovascular complications, which initially manifests as cardiac hypertrophy, myocardial fibrosis, dysfunctional remodeling, and diastolic dysfunction, followed by systolic dysfunction, and eventually end with acute heart failure. Molecular mechanisms underlying these pathological changes in diabetic hearts are complicated and multifactorial, including but not limited to insulin resistance, oxidative stress, lipotoxicity, cardiomyocytes apoptosis or autophagy, inflammatory response, and myocardial metabolic dysfunction. With the development of molecular biology technology, accumulating evidence illustrates that members of the class O of Forkhead box (FoxO) transcription factors are vital for maintaining cardiomyocyte metabolism and cell survival, and the functions of the FoxO family proteins can be modulated by a wide variety of post-translational modifications including phosphorylation, acetylation, ubiquitination, arginine methylation, and O-glycosylation. In this review, we highlight and summarize the most recent advances in two members of the FoxO family (predominately FoxO1 and FoxO3a) that are abundantly expressed in cardiac tissue and whose levels of gene and protein expressions change as DCM progresses, with the goal of providing valuable insights into the pathogenesis of diabetic cardiovascular complications and discussing their therapeutic potential and possible effects of salvianolic acids, a natural product.

Activation of 20-HETE Synthase Triggers Oxidative Injury and Peripheral Nerve Damage in Type 2 Diabetic Mice

Diabetic Peripheral Neuropathy (DPN), highly prevalent among patients with diabetes, is characterized by peripheral nerve dysfunction. Reactive Oxygen Species (ROS) overproduction has been suggested to orchestrate diabetic complications including DPN. Untargeted antioxidant therapy has exhibited limited efficacy, highlighting a critical need to explore ROS sources altered in a cell-specific manner in DPN. Cytochromes P450 (CYP) enzymes are prominent sources of ROS. Particularly, the 20-HETE synthase, CYP4A, is reported to mediate diabetes-induced renal, retinal, and cardiovascular injuries. This work investigates the role of CYP4A/20-HETE in DPN and their mechanisms of action. Non-obese type 2 Diabetic mice (MKR) were used and treated with a CYP4A-inhibitor (HET0016) or AMPK-activator (Metformin). Peripheral nerves of MKR mice reflect increased CYP4A and 20-HETE levels, concurrent with altered myelin proteins and sensorimotor deficits. This was associated with increased ROS production and altered Beclin-1 and LC3 protein levels, indicative of disrupted autophagic responses in tandem with AMPK inactivation. AMPK activation via Metformin restored nerve integrity, reduced ROS production, and regulated autophagy. Interestingly, similar outcomes were revealed upon HET0016 treatment whereby ROS production, autophagic responses, and AMPK signaling were normalized in diabetic mice. Altogether, the results highlight hyperglycemia-mediated oxidative injury in DPN through a novel CYP4A/20-HETE/AMPK pathological axis. PERSPECTIVE: To our knowledge, this is the first study to highlight the role of CYPs/20-HETE-induced oxidative injury in the pathogenesis of diabetic peripheral neuropathy. Targeting the identified pathological axis CYP4A/20-HETE/AMPK may be of clinical potential in predicting and alleviating peripheral nerve injury in patients with Type 2 Diabetes Mellitus.

Oleanolic acid induces HCT116 colon cancer cell death through the p38/FOXO3a/Sirt6 pathway

Oleanolic acid (OA) is a natural compound that possesses numerous beneficial health effects, including anticancer activity. The current study aimed to investigate the role of forkhead box O3a (FOXO3a) in autophagy/mitophagy by OA in HCT116 cell line. OA dose-dependently reduced viability of HCT116 cells, with IC₅₀ = 29.8 μΜ. The expression of cleaved caspase-3 and poly (ADP-ribose) polymerase 1 increased after OA treatment, suggesting induction of apoptosis. Concurrently, OA induced autophagy, evidenced by increased expression of Beclin-1, autophagy-related protein 5 and microtubule-associated protein1A/1B-light chain 3 beta (LC3B), which played a prosurvival role. The induction of mitophagy was suggested by increased expression of p62 and PTEN-induced kinase 1 and reduced expression of translocase of outer mitochondrial membrane 20, which colocalized with LC3B. OA also induced nuclear accumulation of forkhead box O3a (FOXO3a). The cytotoxic activity of OA coincided with upregulation of p38. Inhibition of p38 led to increase in FOXO3a and NAD⁺-dependent deacetylase sirtuin 6 expression. In vivo, OA inhibited tumor growth in colon cancer xenograft mice. Our results suggest concomitant induction of apoptosis and prosurvival mitophagy by OA in colon cancer via p38/FOXO3a/Sirt6 signaling. Additionally, our data demonstrate that OA can chemosensitize colon cancer cells to 5-fluorouracil (5-FU).

Autophagy and beyond: Unraveling the complexity of UNC-51-like kinase 1 (ULK1) from biological functions to therapeutic implications

UNC-51-like kinase 1 (ULK1), as a serine/threonine kinase, is an autophagic initiator in mammals and a homologous protein of autophagy related protein (Atg) 1 in yeast and of UNC-51 in Caenorhabditis elegans. ULK1 is well-known for autophagy activation, which is evolutionarily conserved in protein transport and indispensable to maintain cell homeostasis. As the direct target of energy and nutrition-sensing kinase, ULK1 may contribute to the distribution and utilization of cellular resources in response to metabolism and is closely associated with multiple pathophysiological processes. Moreover, ULK1 has been widely reported to play a crucial role in human diseases, including cancer, neurodegenerative diseases, cardiovascular disease, and infections, and subsequently targeted small-molecule inhibitors or activators are also demonstrated. Interestingly, the non-autophagy function of ULK1 has been emerging, indicating that non-autophagy-relevant ULK1 signaling network is also linked with diseases under some specific contexts. Therefore, in this review, we summarized the structure and functions of ULK1 as an autophagic initiator, with a focus on some new approaches, and further elucidated the key roles of ULK1 in autophagy and non-autophagy. Additionally, we also discussed the relationships between ULK1 and human diseases, as well as illustrated a rapid progress for better understanding of the discovery of more candidate small-molecule drugs targeting ULK1, which will provide a clue on novel ULK1-targeted therapeutics in the future.

An auto-antibody identified from phenotypic directed screening platform shows host immunity against EV-A71 infection

Background

Enterovirus A71 (EV-A71) is a neurotropic virus which may cause severe neural complications, especially in infants and children. The clinical manifestations include hand-foot-and-mouth disease, herpangina, brainstem encephalitis, pulmonary edema, and other severe neurological diseases. Although there are some vaccines approved, the post-marketing surveillance is still unavailable. In addition, there is no antiviral drugs against EV-A71 available.

Methods

In this study, we identified a novel antibody that could inhibit viral growth through a human single chain variable fragment (scFv) library expressed in mammalian cells and panned by infection with lethal dose of EV-A71.

Results

We identified that the host protein α-enolase (ENO1) is the target of this scFv, and anti-ENO1 antibody was found to be more in mild cases than severe EV-A71 cases. Furthermore, we examined the antiviral activity in a mouse model. We found that the treatment of the identified 07-human IgG₁ antibody increased the survival rate after virus challenge, and significantly decreased the viral RNA and the level of neural pathology in brain tissue.

Conclusions

Collectively, through a promising intracellular scFv library expression and screening system, we found a potential scFv/antibody which targets host protein ENO1 and can interfere with the infection of EV-A71. The results indicate that the usage and application of this antibody may offer a potential treatment against EV-A71 infection.

Dapagliflozin alleviates advanced glycation end product induced podocyte injury through AMPK/mTOR mediated autophagy pathway

Excessive accumulation of advanced glycation end products (AGEs) contributes to autophagy interruption on podocytes and insufficient autophagy on podocytes is accountable to podocyte injury and eventually accelerates the advancement of DN. SGLT2 inhibitors have been confirmed excellent renoprotection in DN whereas the mechanism for such benefit is not fully illustrated. Here, we report dapagliflozin, an SGLT2 inhibitor, ameliorated the pro-inflammatory cytokines release and apoptosis level concomitant with increasing Synaptopodin level on AGE-induced podocytes. Furthermore, dapagliflozin manifested autophagy promotion on AGE-induced podocytes as evident by the upregulated Beclin and LC3II/LC3I ratio levels attendant with the shrunk p62 level. However, The protective effect of dapagliflozin was blunted by 3-MA, an autophagy inhibitor. Additionally, the effect of dapagliflozin on autophagy was relevant to the regulation of the AMPK-mTOR signal pathway. Taken together, dapagliflozin effectively mitigated AGE-induced podocyte injury through AMPK-mTOR mediated upregulation of autophagy. It may offer a novel mechanism to further elucidate the renoprotective effect on SGLT2 inhibitors.

Metformin to decrease COVID-19 severity and mortality: Molecular mechanisms and therapeutic potential

The COVID-19 pandemic caused by the coronavirus SARS-CoV-2 has become a serious challenge for medicine and science. Analysis of the molecular mechanisms associated with the clinical manifestations and severity of COVID-19 has identified several key points of immune dysregulation observed in SARS-CoV-2 infection. For diabetic patients, factors including higher binding affinity and virus penetration, decreased virus clearance and decreased T cell function, increased susceptibility to hyperinflammation, and cytokine storm may make these patients susceptible to a more severe course of COVID-19 disease. Metabolic changes induced by diabetes, especially hyperglycemia, can directly affect the immunometabolism of lymphocytes in part by affecting the activity of the mTOR protein kinase signaling pathway. High mTOR activity can enhance the progression of diabetes due to the activation of effector proinflammatory subpopulations of lymphocytes and, conversely, low activity promotes the differentiation of T-regulatory cells. Interestingly, metformin, an extensively used antidiabetic drug, inhibits mTOR by affecting the activity of AMPK. Therefore, activation of AMPK and/or inhibition of the mTOR-mediated signaling pathway may be an important new target for drug therapy in COVID-19 cases mostly by reducing the level of pro-inflammatory signaling and cytokine storm. These suggestions have been partially confirmed by several retrospective analyzes of patients with diabetes mellitus hospitalized for severe COVID-19.

Trigonelline induces autophagy to protect mesangial cells in response to high glucose via activating the miR-5189-5p-AMPK pathway

BACKGROUND

Diabetic nephropathy (DN) is a primary cause of end-stage renal disease. Increasing evidence indicates that microRNAs (miRNAs) are involved in DN pathogenesis. Trigonelline (TRL) has been shown to lower blood sugar and cholesterol levels, promote nerve regeneration, and exert anti-cancer and sedative properties.

METHOD

The effect of TRL on human mesangial cell (HMC) growth was assessed using the MTT assay. Differentially expressed miRNAs were validated using real-time quantitative polymerase chain reaction (real-time PCR). Bioinformatics, cell transfection, and Western blot analyses were utilized to confirm the binding of miR-5189-5p to HIF1AN. The effects of miR-5189-5 expression on cell proliferation were also assessed. Western blot analysis was used to determine the activation of multiple signaling molecules including phosphorylated-(p)-AMPK, SIRT1, LC3B, p62, and Beclin-1 in the autophagy pathway.

RESULTS

TRL improved proliferation, increased the expression of miR-5189-5p, reduced HIF1AN, and restored the inhibition of autophagy in HMCs induced by high glucose. MiR-5189-5p mimics inhibited HIF1AN expression, and the miR-5189-5p inhibitor increased HIF1AN expression. MiR-5189-5p mimics significantly improved the proliferation of HMCs induced by high glucose, reduced the relative protein expression of p-AMPK, SIRT1, LC3B, and Beclin-1, and significantly increased the relative protein expression of p62.

CONCLUSION

We showed that TRL up-regulated miR-5189-5p expression, activated the AMPK pathway, and activated autophagy in HMCs. Our study demonstrates that TRL could be a new treatment strategy to protect mesangial cells in response to high glucose.

Icariin ameliorate Alzheimer's disease by influencing SIRT1 and inhibiting Aβ cascade pathogenesis

Of all types of dementia, Alzheimer's disease is the type that has the highest proportion of cases and is the cause of substantial medical and economic burden. The mechanism of Alzheimer's disease is closely associated with the aggregation of amyloid-β protein and causes neurotoxicity and extracellular accumulation in the brain and to intracellular neurofibrillary tangles caused by tau protein hyperphosphorylation in the brain tissue. Previous studies have demonstrated that sirtuin1 downregulation is involved in the pathological mechanism of Alzheimer's disease. The decrease of sirtuin1 level would cause Alzheimer's disease by means of promoting the amyloidogenic pathway to generate amyloid-β species and thereby triggering amyloid-β cascade reaction, such as tau protein hyperphosphorylation, neuron autophagy, neuroinflammation, oxidative stress, and neuron apoptosis. Currently, there is no effective treatment for Alzheimer's disease, it is necessary to develop new treatment strategies. According to the theory of traditional Chinese medicine and based on the mechanism of the disease, tonifying the kidneys is one of the principles for the treatment of Alzheimer's disease and Epimedium is a well-known Chinese medicine for tonifying kidney. Therefore, investigating the influence of the components of Epimedium on the pathological characteristics of Alzheimer's disease may provide a reference for the treatment of Alzheimer's disease in the future. In this article, we summarise the effects and mechanism of icariin, the main ingredient extracted from Epimedium, in ameliorating Alzheimer's disease by regulating sirtuin1 to inhibit amyloid-β protein and improve other amyloid-β cascade pathogenesis.

Effect of Lactobacillus fermentum TKSN041 on improving streptozotocin-induced type 2 diabetes in rats

With the increasing incidence of type 2 diabetes, it is imperative to identify how to effectively prevent or treat this disease. Studies have shown that some lactic acid bacteria can improve type 2 diabetes with almost no side effects. Therefore, in this experimental study, we explored the preventive and therapeutic effects of Lactobacillus fermentum TKSN041 (L. fermentum TKSN041) on streptozotocin-induced type 2 diabetes in rats. The results showed that L. fermentum TKSN041 could reduce the amount of water intake, reduce weight loss, and control the increase in the fasting blood glucose level of diabetic rats. The organ index and tissue section results showed that L. fermentum TKSN041 could reduce the damage caused by diabetes to the liver, kidney, spleen, pancreatic, and brain tissue. Furthermore, L. fermentum TKSN041 decreased the levels of triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL), aminotransferase (AST), alanine aminotransferase (ALT), glycated serum proteins (GSP), malondialdehyde (MDA), interleukin 1 beta (IL-1β), interleukin 6 (IL-6), and endothelin 1 (ET-1) in serum and increased the serum levels of high-density lipoprotein cholesterol (HDL) and interleukin 10 (IL-10). Finally, L. fermentum TKSN041 up-regulated the mRNA and protein expressions of NF-kappa-B inhibitor-α (IκB-α), AMP-activated protein kinase (AMPK), insulin receptor substrate-1 (IRS-1), liver kinase B1 (LKB1), and glucose transporter 4 (GLUT4) and down-regulated those of nuclear factor-κBp65 (NFκB-p65) and tumor necrosis factor alpha (TNF-α). Furthermore, LF-TKSN041 up-regulated the mRNA expressions of peroxisome proliferator-activated receptor γ (PPAR-γ) and down-regulated neuropeptide Y (NPY), sterol regulatory element-binding protein-1 (SREBF-1), and vascular endothelial growth factor (VEGF). These results suggest that L. fermentum TKSN041 may be a useful intervention factor for the prevention or treatment of type 2 diabetes induced by STZ. Clinical trials are needed to further demonstrate its effectiveness.

Sarsasapogenin restores podocyte autophagy in diabetic nephropathy by targeting GSK3β signaling pathway

Podocyte injury following abnormal podocyte autophagy plays an indispensable role in diabetic nephropathy (DN), therefore, restoration of podocyte autophagy is considered as a feasible strategy for the treatment of DN. Here, we investigated the preventive effects of sarsasapogenin (Sar), the main active ingredient in Anemarrhena asphodeloides Bunge, on the podocyte injury in diabetic rats, and tried to illustrate the mechanisms underlying the effects in high glucose (HG, 40 mM)-treated podocytes (MPs). Diabetes model was established in rats with single streptozocin (60 mg· kg^-1) intraperitoneal administration. The rats were then treated with Sar (20, 60 mg· kg^-1· d^-1, i.g.) or a positive control drug insulin (INS) (40 U· kg^-1· d^-1, i.h.) for 10 weeks. Our results showed that both Sar and insulin precluded the decreases of autophagy-related proteins (ATG5, Beclin1 and LC3B) and podocyte marker proteins (podocin, nephrin and synaptopodin) in the diabetic kidney. Furthermore, network pharmacology was utilized to assess GSK3β as the potential target involved in the action of Sar on DN and were substantiated by significant changes of GSK3β signaling in the diabetic kidney. The underlying protection mechanisms of Sar were explored in HG-treated MPs. Sar (20, 40 μM) or insulin (50 mU/L) significantly increased the expression of autophagy- related proteins and podocyte marker proteins in HG-treated MPs. Furthermore, Sar or insulin treatment efficiently regulatedphosphorylation at activation and inhibition sites of GSK3β. To sum up, this study certifies that Sar meliorates experimental DN through targeting GSK3β signaling pathway and restoring podocyte autophagy.

Effect of vitamin D3 supplementation on hepatic lipid dysregulation associated with autophagy regulatory AMPK/Akt-mTOR signaling in type 2 diabetic mice

Vitamin D3 has been reported to protect liver against non-alcoholic fatty liver disease (NAFLD) by attenuating hepatic lipid dysregulation in type 2 diabetes mellitus (T2DM). However, the mechanism of vitamin D3 on hepatic lipid metabolism-associated autophagy in hyperglycemia-induced NAFLD remains yet to be exactly elucidated. C57BL/6J mice were intraperitoneally injected with 30 mg/kg of streptozotocin and fed a high-fat diet for induction of diabetes. All mice were administered with vehicle or vitamin D3 (300 ng/kg or 600 ng/kg) by oral gavage for 12 weeks. Histological demonstrations of the hepatic tissues were obtained by H&E staining and the protein levels related to lipid metabolism and autophagy signaling were analyzed by Western blot. Treatment with vitamin D3 improved insulin resistance, liver damage, and plasma lipid profiles, and decreased hepatic lipid content in the diabetic mice. Moreover, vitamin D3 administration ameliorated hepatic lipid dysregulation by downregulating lipogenesis and upregulating lipid oxidation under diabetic condition. Importantly, vitamin D3 treatment induced autophagy by activating AMP-activated protein kinase (AMPK), inactivating Akt and ultimately blocking mammalian target of rapamycin (mTOR) activation in the T2DM mice. Additionally, vitamin D3 was found to be effective in anti-apoptosis and anti-fibrosis in the liver of diabetic mice. The results suggested that vitamin D3 may ameliorate hepatic lipid dysregulation by activating autophagy regulatory AMPK/Akt-mTOR signaling in T2DM, providing insights into its beneficial effects on NAFLD in type 2 diabetic patients.

Activation of AMPK restored impaired autophagy and inhibited inflammation reaction by up-regulating SIRT1 in acute pancreatitis

AIMS

Acute pancreatitis (AP) is a common inflammatory disorder with high incidence and mortality. AMPK-SIRT1 pathway is involved in a variety of diseases, but its role in AP remains elusive. This study was aimed to explore the role of AMPK-SIRT1 pathway in AP.

MAIN METHODS

AP models in vivo and vitro were constructed by intraperitoneal administration of L-arginine and caerulein-stimulated respectively. Rat serum amylase, IL-6 and TNF-α were determined by ELISA. The expression levels of AMPK, SIRT1, Beclin-1, LC3 and p62 were determined by qRT-PCR and western blot. The number of autophagosome was checked by transmission electron microscope.

KEY FINDINGS

Compared with NC rats, serum amylase, IL-6 and TNF-α were increased in AP rats. The expressions of AMPK and SIRT1 were decreased, while Beclin-1, LC3II/Iratio and p62 were markedly increased in AP rats. After activation of AMPK by metformin, expressions of p-AMPKα, SIRT1 were significantly raised, while expressions of Beclin-1, LC3 II/I, p62, TNF-α, IL-6 were reduced, and the number of autophagosome was decreased significantly in caerulein-stimulated AR42J cells. The inhibition of AMPK by compound C obtained opposite results.

SIGNIFICANCE

During AP occurrence, p-AMPK and SIRT1 were down-regulated, leading to the accumulation of p62, increase of autophagic vacuoles, damage of autophagy, and the occurrence of inflammation. It hinted that activation of AMPK restored impaired autophagy and inhibited inflammation reaction by up-regulating SIRT1. Our findings might provide important theoretical basis for explaining the pathogenesis of AP and investigating therapeutic target to treat and prevent AP.

The Association Between Metformin Treatment and Outcomes in Type 2 Diabetes Mellitus Patients With Heart Failure With Preserved Ejection Fraction: A Retrospective Study

Background: Metformin is the first-line antidiabetic medication for type 2 diabetes mellitus (T2DM). However, the association between metformin and outcomes in T2DM patients with heart failure with preserved ejection fraction (HFpEF) is still unknown. We aimed to explore the association between metformin and adverse outcome in T2DM patients with HFpEF.

Methods: A total of 372 T2DM patients with HFpEF hospitalized from January 1, 2013, to December 31, 2017, were included in this retrospective cohort study. There were 113 and 259 subjects in metformin and non-metformin group, respectively. Subjects were followed up for all-cause mortality, cardiovascular death, all-cause hospitalization, and heart failure hospitalization.

Results: The median follow-up period was 47 months. Eleven patients (2.49% per patient-year) in the metformin group and 56 patients (5.52% per patient-year) in the non-metformin group deceased during follow-up (P = 0.031). However, a multivariable Cox regression failed to show that metformin was an independent factor of all-cause mortality [HR (95% CI) = 0.682 (0.346–1.345); P = 0.269]. A subgroup analysis revealed a significant association between metformin and all-cause mortality in patients with a higher hemoglobin A1c (HbA1c) level (HbA1c ≥7%) [HR (95% CI) = 0.339 (0.117–0.997); P = 0.045]. The 4-year estimated number needed to treat (NNT) with metformin compared with non-metformin for all-cause mortality was 12 in all populations and 8 in the HbA1c ≥7% subgroup.

Conclusions: Metformin was not independently associated with clinical outcomes in patients with T2DM and HFpEF, but was associated with lower all-cause mortality in the subgroup of patients with poor glycemic control. Prospective, randomized controlled trials are needed to further verify these findings.

Geniposide Improves Diabetic Nephropathy by Enhancing ULK1-Mediated Autophagy and Reducing Oxidative Stress through AMPK Activation

Diabetic nephropathy (DN) is a common pathological feature in patients with diabetes and the leading cause of end-stage renal disease. Although several pharmacological agents have been developed, the management of DN remains challenging. Geniposide, a natural compound has been reported for anti-inflammatory and anti-diabetic effects; however, its role in DN remains poorly understood. This study investigated the protective effects of geniposide on DN and its underlying mechanisms. We used a C57BL/6 mouse model of DN in combination with a high-fat diet and streptozotocin after unilateral nephrectomy and treated with geniposide by oral gavage for 5 weeks. Geniposide effectively improves DN-induced renal structural and functional abnormalities by reducing albuminuria, podocyte loss, glomerular and tubular injury, renal inflammation and interstitial fibrosis. These changes induced by geniposide were associated with an increase of AMPK activity to enhance ULK1-mediated autophagy response and a decrease of AKT activity to block oxidative stress, inflammation and fibrosis in diabetic kidney. In addition, geniposide increased the activities of PKA and GSK3β, possibly modulating AMPK and AKT pathways, efficiently improving renal dysfunction and ameliorating the progression of DN. Conclusively, geniposide enhances ULK1-mediated autophagy and reduces oxidative stress, inflammation and fibrosis, suggesting geniposide as a promising treatment for DN.

Potential Antidiabetic Effects of Seaweed Extracts by Upregulating Glucose Utilization and Alleviating Inflammation in C2C12 Myotubes

Seaweed is known to have various health-promoting effects. However, the mechanisms underlying seaweed’s antidiabetic effects remain unclear. We investigated the potential antidiabetic effects of seaweed water extracts and further examined their mechanism(s) using C2C12 mouse skeletal muscle cells. Briefly, we screened the physiochemical properties of seven seaweed extracts by comparing the antioxidant and α-glucosidase inhibitory effects. Among them, three seaweed extracts, Undaria pinnatifida sporophyll (UPS), Codium fragile (CF), and Gracilaria verrucosa (GV), were selected for further testing of their possible antidiabetic effects with underlying mechanisms using C2C12 myotubes. Consistent with the superior α-glucosidase inhibition of the three seaweed extracts, the extracts also enhanced glucose utilization in myotubes compared to the control. The upregulated glucose uptake by the seaweed extracts was reversed by an AMP-activated protein kinase (AMPK) inhibitor, compound C, in the UPS- and CF-treated groups. Furthermore, all three seaweed extracts significantly promoted the phosphorylation of AMPK which was completely blocked by pretreating with compound C. In addition, all three extracts reduced lipopolysaccharide-simulated TNF-α production in C2C12 cells. Our results demonstrated that all three seaweed extracts exhibited antidiabetic properties through not only the inhibition of glucose absorption but also the promotion of glucose utilization. Moreover, the regulation of inflammatory cytokine production by the extracts suggested their potential anti-inflammatory property which might play a critical role in protecting insulin sensitivity in a chronic inflammatory state. Taken together, UPS, CF, and GV are a promising source to modulate the glucose absorption and utilization in muscle cells partially via the AMPK pathway.

Salidroside protects against diabetes mellitus-induced kidney injury and renal fibrosis by attenuating TGF-β1 and Wnt1/3a/β-catenin signalling

This study evaluated if the nephroprotective effect of Salidroside in type 1 diabetes mellitus (T1DM) involves modulation of Wnt/β-catenin signalling pathways. Control or Streptozotocin (STZ, 50 mg/kg, iv)-induced T1DM adult male Wister rats were treated with the vehicle and Salidroside (100 mg/kg, orally) for 8 weeks daily. As compared to T1DM-induced rats, Salidroside improved kidney structure, reduced urinary protein and albumin level, increased creatinine clearance, and suppressed renal fibrosis. It also decreased mRNA and protein levels of Wnt1, Wnt3, and TGF-β1, phosphorylation of Smad-3, total and nuclear levels of β-catenin, and levels and activities of cleaved caspase-3. Concomitantly, Salidroside significantly increased the levels of p-β-catenin (Ser33/37 /Thr41 ) and suppressed protein levels of Axin-2, fibronectin, and, mRNA and protein levels of collagen IIIa, the main targets of β-catenin. In both control and T1DM rats, Salidroside significantly lowered fasting glucose levels and reduced renal levels of reactive oxygen species (ROS) p-and GS3Kβ (Ser9) but significantly increased levels of SOD and GSH. In conclusion, Salidroside protected the kidney of rats against T1DM-induced injury and fibrosis by activating GS3Kβ-induced inhibition of Wnt1/Wnt3a β-catenin. This was associated with hypoglycaemic and antioxidant effects.

P2Y2R contributes to the development of diabetic nephropathy by inhibiting autophagy response

OBJECTIVE

Diabetic nephropathy (DN) is one of the most common complications of diabetes and a critical risk factor for developing end-stage renal disease. Activation of purinergic receptors, including P2Y2R has been associated with the pathogenesis of renal diseases, such as polycystic kidney and glomerulonephritis. However, the role of P2Y2R and its precise mechanisms in DN remain unknown. We hypothesised that P2Y2R deficiency may play a protective role in DN by modulating the autophagy signalling pathway.

METHODS

We used a mouse model of DN by combining a treatment of high-fat diet and streptozotocin after unilateral nephrectomy in wild-type or P2Y2R knockout mice. We measured renal functional parameter in plasma, examined renal histology, and analysed expression of autophagy regulatory proteins.

RESULTS

Hyperglycaemia and ATP release were induced in wild type-DN mice and positively correlated with renal dysfunction. Conversely, P2Y2R knockout markedly attenuates albuminuria, podocyte loss, development of glomerulopathy, renal tubular injury, apoptosis and interstitial fibrosis induced by DN. These protective effects were associated with inhibition of AKT-mediated FOXO3a (forkhead box O3a) phosphorylation and induction of FOXO3a-induced autophagy gene transcription. Furthermore, inhibitory phosphorylation of ULK-1 was decreased, and the downstream Beclin-1 autophagy signalling was activated in P2Y2R deficiency. Increased SIRT-1 (sirtuin-1) and FOXO3a expression in P2Y2R deficiency also enhanced autophagy response, thereby ameliorating renal dysfunction in DN.

CONCLUSIONS

P2Y2R contributes to the pathogenesis of DN by impairing autophagy and serves as a therapeutic target for treating DN.

AMPK allostery: A therapeutic target for the management/treatment of diabetic nephropathy

Diabetic nephropathy (DN) is a chronic complication of diabetes mellitus (DM) with approximately 30-40% of patients with DM developing nephropathy, and it is the leading cause of end-stage renal diseases and diabetic morbidity. The pathogenesis of DN is primarily associated with irregularities in the metabolism of glucose and lipid leading to hyperglycemia-induced oxidative stress, which has been a major target together with blood pressure regulation in the control of DN progression. However, the regulation of 5' adenosine monophosphate-activated protein kinase (AMPK), a highly conserved protein kinase for maintaining energy balance and cellular growth and repair has been implicated in the development of DM and its complications. Therefore, targeting AMPK pathway has been explored as a therapeutic strategy for the treatment of diabetes and its complication, although most of the mechanisms have not been fully elucidated. In this review, we discuss the structure of AMPK relevant to understanding its allosteric regulation and its role in the pathogenesis and progression of DN. We also identify therapeutic agents that modulate AMPK and its downstream targets with their specific mechanisms of action in the treatment of DN.

Annexin A1: A Bane or a Boon in Cancer? A Systematic Review

Annexin A1 has been extensively investigated as an anti-inflammatory protein, but its role in different types of cancer has not been consolidated in a single systematic review to date. Thus, the aim of this paper is to systematically review and critically analyse 18 studies (in-vivo and in-vitro) to consolidate, in a concerted manner, all the information on differential expression of Annexin A1 in different types of cancer and the role this protein plays in tumorigenesis. Pubmed, Scopus, Web of Science, and ScienceDirect were used for the literature search and the keywords used are “annexin A1,” “lipocortin 1,” “cancer,” “malignancy,” “neoplasm,” “neoplasia,” and “tumor.” A total of 1128 articles were retrieved by implementing a standard search strategy subjected to meticulous screening processes and 442 articles were selected for full article screening. A total of 18 articles that adhered to the inclusion criteria were included in the systematic review and these articles possessed low to moderate bias. These studies showed a strong correlation between Annexin A1 expression and cancer progression via modulation of various cancer-associated pathways. Differential expression of Annexin A1 is shown to play a role in cellular proliferation, metastasis, lymphatic invasion, and development of resistance to anti-cancer treatment. Meta-analysis in the future may provide a statistically driven association between Annexin A1 expression and malignancy progression.

Geniposide alleviates diabetic nephropathy of mice through AMPK/SIRT1/NF-κB pathway

Geniposide (GE) can effectively inhibit diabetic nephropathy (DN), but its mechanism is unclear. The objective of this study was to explore the antidiabetic nephropathy effects of GE both in high fat diet/streptozotocin-induced DN mice and in high glucose-induced podocyte model. Renal function in DN mice was evaluated by levels of serum creatinine (Scr) and blood urea nitrogen (BUN). Renal inflammation was appraised by pro-inflammatory cytokines: Tumor necrosis factor α (TNF-α), Interleukin 6 (IL-6) and IL-1β via ELISA assay. Renal histopathology analysis was conducted via hematoxylin and eosin, Masson and periodic acid-silver metheramine staining. Cellular viability was measured by Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay. Moreover, the related proteins p-NF-κB, ASC, Cleave-IL-1β, NLRP3, Cleave-Caspase-1 and GSDMD-N in AMPK/SIRT1/NF-κB pathway were assayed by Western blotting. In order to further investigate the effects of GE on podocytes, we also assessed these protein levels in AMPK/SIRT1/NF-κB pathway after siRNA-AMPK intervention by Western blotting. GE alleviated renal dysfunction as evidenced by decreased levels of Scr, BUN, TNF-α, IL-6 and IL-1β. Histological examination revealed GE effectively attenuated kidney damage, including glomerular basement membrane thickening and inflammatory cells infiltration. AMPK, p-AMPK and SIRT1 levels were obviously decreased both in DN mice and in podocyte model, but GE reversed these changes. The protein expressions in APMK/SIRT1/NF-κB pathway were significantly decreased by GE treatment. These results suggested that GE could efficiently block oxidative stress and inflammatory responses accompanied with pyroptosis, thus inhibiting the development of DN, and its mechanism might be related to APMK/SIRT1/NF-κB pathway.

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.

AMPK in microvascular complications of diabetes and the beneficial effects of AMPK activators from plants

BACKGROUND

Diabetes mellitus is a multifactorial disorder with the risk of micro- and macro-vascular complications. High glucose-induced derangements in metabolic pathways are primarily associated with the initiation and progression of secondary complications namely, diabetic nephropathy, neuropathy, and retinopathy. Adenosine monophosphate-activated protein kinase (AMPK) has emerged as an attractive therapeutic target to treat various metabolic disorders including diabetes mellitus. It is a master metabolic regulator that helps in maintaining cellular energy homeostasis by promoting ATP-generating catabolic pathways and inhibiting ATP-consuming anabolic pathways. Numerous pharmacological and plant-derived bioactive compounds that increase AMP-activated protein kinase activation has shown beneficial effects by mitigating secondary complications namely retinopathy, nephropathy, and neuropathy.

PURPOSE

The purpose of this review is to highlight current knowledge on the role of AMPK and its activators from plant origin in diabetic microvascular complications.

METHODS

Search engines such as Google Scholar, PubMed, Science Direct and Web of Science are used to extract papers using relevant key words. Papers mainly focusing on the role of AMPK and AMPK activators from plant origin in diabetic nephropathy, retinopathy, and neuropathy was chosen to be highlighted.

RESULTS

According to results, decrease in AMPK activation during diabetes play a causative role in the pathogenesis of diabetic microvascular complications. Some of the plant-derived bioactive compounds were beneficial in restoring AMPK activity and ameliorating diabetic microvascular complications.

CONCLUSION

AMPK activators from plant origin are beneficial in mitigating diabetic microvascular complications. These pieces of evidence will be helpful in the development of AMPK-centric therapies to mitigate diabetic microvascular complications.

Enzyme-based autophagy in anti-neoplastic management: From molecular mechanisms to clinical therapeutics

Autophagy is an evolutionarily conserved self-cannibalization process commonly found in all eukaryotic cells. Through autophagy, long-lived or damaged organelles, superfluous proteins, and pathogens are sequestered and encapsulated into the double-membrane autophagosomes prior to fusion with lysosomes for ultimate degradation and recycling. Given that autophagy is deemed both protective and detrimental in malignancies, the clinical therapeutic utilization of autophagy modulators in cancer has attracted immense attentions over the past decades. Dependence of tumor cells on autophagy during amino acid insufficiency or deprivation has prompted us to explore the underlying autophagy regulatory mechanisms to inject amino acid degrading enzymes and enzyme-based strategies into therapeutic maneuvers of autophagy in cancer.

Salidroside ameliorates diabetic nephropathy in rats by activating renal AMPK/SIRT1 signaling pathway

This study investigated if the nephroprotective effect of Salidroside T1DM rats involves activation of AMPK/SIRT1. Rats were divided into control or T1DM and treated with vehicle or Salidroside (100 mg/kg) for 56 days. Mesangial cells were cultured in LG or HG media with or without Salidroside (100 µM/L) for 24 hr. Also, HG + Salidroside-treated cells were pre-incubated with EX-527 or compound C (CC) for 1 hr. With reducing glucose levels, Salidroside improved kidney structure/function in the T1DM rat. It also increased GSH and Bcl-2 levels in control and T1DM rats and inhibited ROS, increased activation of AMPK and nuclear SIRT1, and lowered acetylation of P53 and FOXO-1 in control and T1DM rats and in LG and HG-treated cells. These effects were abolished by EX-527 and CC. Also, CC decreased the nuclear levels of SIRT1. In conclusion, Salidroside attenuates DN in T1DM rats by activation of AMPK and subsequently, SIRT1. PRACTICAL APPLICATIONS: This animal and pre-clinical study shows that Salidroside is able to ameliorate DN in T1DM-induced rats and showed that it mainly acts by a hypoglycemic effect and activation of renal AMPK/SIRT1 axis. Given the wide tissue stimulatory effect of AMPK on peripheral glucose utilization, lipogenesis, and other cell signaling pathways, these data are encouraging to investigate the anti-diabetic effect of glycoside in more clinical trials.

Rapamycin Supplementation May Ameliorate Erectile Function in Rats With Streptozotocin-Induced Type 1 Diabetes by Inducing Autophagy and Inhibiting Apoptosis, Endothelial Dysfunction, and Corporal Fibrosis

INTRODUCTION

Erectile dysfunction (ED), which is common in patients with diabetes mellitus (DM), seriously affects quality of life. Previous studies on the treatment of DM-induced ED (DMED) involve autophagy, but the specific effect and mechanism of treatment are not yet clear.

AIM

To investigate the effect and mechanism of rapamycin, an autophagy inducer, in ameliorating DMED.

METHODS

45 male Sprague-Dawley rats (7 weeks old) were used in the experiment. 8 rats were randomly selected as the control group; the other rats were treated with streptozotocin to induce type 1 DM. After 10 weeks, an apomorphine test was used to confirm DMED. Rats with DMED were intraperitoneally injected with rapamycin or vehicle for 3 weeks. Rats in the control group were injected with saline. Erectile function in rats was measured by electrically stimulating the cavernous nerve. The penises were then harvested for histologic examinations, ribonucleic acid (RNA), and protein levels of related factors by immunohistochemistry, immunofluorescence, real-time polymerase chain reaction, enzyme-linked immunosorbent assay, and Western blot.

MAIN OUTCOME MEASURE

Erectile function was evaluated by maximum intracavernous pressure and mean arterial pressure. Penile tissues were used to perform histologic examinations and to determine the RNA and protein levels.

RESULTS

Erectile function, which was impaired in rats with DMED, was significantly ameliorated in the DMED + rapamycin group. The nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) pathway was inhibited in the DMED group, and rapamycin significantly reduced this inhibition. The DMED group showed increased autophagy and apoptosis level compared with the non-diabetic group, and rapamycin increased the autophagy level and decreased the apoptosis level in the penis. Penile fibrosis was more severe in the DMED group than in the control group and was partially but significantly improved in the DMED + rapamycin group compared with the DMED group. The adenosine monophosphate-activated protein kinase (AMPK)/mammalian target of rapamycin kinase (mTOR) and PI3K/AKT/mTOR pathways were activated, and the mTOR (regulatory associated protein of mTOR, complex 1 [raptor])/p70 ribosomal protein S6 kinase (p70S6K) pathway was inhibited in the DMED group. Compared with DMED group, rapamycin led to lower AMPK/mTOR and AKT/mTOR pathways expression, a higher degree of mTOR (raptor)/p70S6K pathway inhibition, and no change in the mTORC2-related pathway.

CLINICAL IMPLICATIONS

Rapamycin was effective in restoring erectile function in type 1 DMED models.

STRENGTH AND LIMITATIONS

This study suggested for the first time that rapamycin, an autophagy inducer, is effective in restoring erectile function in rats with diabetes. However, the rat model might not represent the human condition.

CONCLUSION

Rapamycin improved erectile function in rats with DMED, likely by promoting autophagy, inhibiting apoptosis and fibrotic activity, and ameliorating endothelial function. These findings provide evidence of a potential treatment option for DMED. Lin H, Wang T, Ruan Y, et al. Rapamycin supplementation may ameliorate erectile function in rats with streptozotocin-induced type 1 diabetes by inducing autophagy and inhibiting apoptosis, endothelial dysfunction, and corporal fibrosis. J Sex Med 2018;15:1246-1259.

Theaflavin 3,3'-digallate reverses the downregulation of connexin 43 and autophagy induced by high glucose via AMPK activation in cardiomyocytes

Theaflavin 3,3'-digallate (TF3), is reported to protect cardiomyocytes from lipotoxicity and reperfusion injury. However, the role of TF3 in the protection of high-glucose injury is still poorly understood. This study investigated the protective effects of TF3 on gap junctions and autophagy in neonatal cardiomyocytes (NRCMs). NRCMs preincubated with high glucose were coincubated with TF3. The expression of connexins and autophagy-related proteins was determined. The functioning of gap-junctional intercellular communication (GJIC) was measured by a dye transfer assay. Adenosine monophosphate-activated protein kinase (AMPK) activity was determined by western blot. Moreover, AMPK was activated with aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR) or inhibited by AMPKα small interfering RNA (siRNA) to explore the role of AMPK in the modulation of connexin 43 (Cx43) and autophagy. Meanwhile, autophagy was activated or blocked to observe the change in Cx43 expression. It was found that the protein expression of Cx43 and autophagy-related proteins was increased in a TF3 dose- and time-dependent manner under high glucose. TF3 also recovered the reduced GJIC function induced by high glucose concentrations. TF3 activated phosphorylated AMPK in a time-dependent way. AMPKα siRNA abrogated the protection of TF3, while AICAR showed similar results compared to the TF3 treatment. Meanwhile, autophagy activation caused decreased Cx43, while cotreatment with baf A1 enhanced Cx43 expression further compared with the TF3 treatment alone under high glucose. We concluded that TF3 partly reversed the inhibition of Cx43 expression and autophagy induced by high glucose in NRCMs, partly by restoring AMPK activity. Inhibition of autophagy might be protective by preserving Cx43 expression in NRCMs stimulated by high glucose.

Matrine attenuates oxidative stress and cardiomyocyte apoptosis in doxorubicin-induced cardiotoxicity via maintaining AMPKα/UCP2 pathway

Oxidative stress and cardiomyocyte apoptosis are involved in the pathogenesis of doxorubicin (DOX)-induced cardiotoxicity. Matrine is well-known for its powerful anti-oxidant and anti-apoptotic capacities. Our present study aimed to investigate the effect of matrine on DOX-induced cardiotoxicity and try to unearth the underlying mechanisms. Mice were exposed with DOX to generate DOX-induced cardiotoxicity or normal saline as control. H9C2 cells were used to verify the effect of matrine in vitro. DOX injection triggered increased generation of reactive oxygen species (ROS) and excessive cardiomyocyte apoptosis, which were significantly mitigated by matrine. Mechanistically, we found that matrine ameliorated DOX-induced uncoupling protein 2 (UCP2) downregulation, and UCP2 inhibition by genipin could blunt the protective effect of matrine on DOX-induced oxidative stress and cardiomyocyte apoptosis. Besides, 5'-AMP-activated protein kinase α2 (Ampkα2) deficiency inhibited matrine-mediated UCP2 preservation and abolished the beneficial effect of matrine in mice. Besides, we observed that matrine incubation alleviated DOX-induced H9C2 cells apoptosis and oxidative stress level via activating AMPKα/UCP2, which were blunted by either AMPKα or UCP2 inhibition with genetic or pharmacological methods. Matrine attenuated oxidative stress and cardiomyocyte apoptosis in DOX-induced cardiotoxicity via maintaining AMPKα/UCP2 pathway, and it might be a promising therapeutic agent for the treatment of DOX-induced cardiotoxicity.

Effects of Single Probiotic- and Combined Probiotic-Fermented Milk on Lipid Metabolism in Hyperlipidemic Rats

Previous studies have shown that probiotics have positive effects on hyperlipidemia by lowering the serum lipid concentration and improving the lipid profile. To explore the mechanism by which probiotic-fermented milk improves lipid metabolism, the transcription of genes regulated by liver X receptors (LXRs), 5′-AMP-activated protein kinase, and the farnesoid X receptor (FXR), which play integral roles in lipid metabolism, was investigated in hyperlipidemic rats. Compared with rats fed a high-fat diet, the administration of probiotic-fermented milk significantly lowered the levels of total cholesterol (TC) and total triglycerides (TG) in rat serum and viscera (P < 0.05) and significantly increased the level of total bile acid in the rat liver and small intestine (P < 0.05). The quantitative PCR results showed that the probiotics ameliorated the TC levels in the rats by activating the transcription of genes involved in the LXR axis, which promoted TC reverse transport and increased the conversion of TC to bile acids. The level of TG in the hyperlipidemic rats was ameliorated by the inhibition of the transcription of carbohydrate reaction element binding protein genes and activation of the transcription of PPARα genes. The regulation of lipid metabolism-related gene transcription by the single probiotic (Lactobacillus rhamnosus LV108)-fermented milk was more effective than that by the combined probiotic (L. rhamnosus LV108, Lactobacillus casei grx12, and Lactobacillus fermentum grx08)-fermented milk (P < 0.05).

Metformin-induced autophagy and irisin improves INS-1 cell function and survival in high-glucose environment via AMPK/SIRT1/PGC-1α signal pathway

In order to explore the protective function of metformin on pancreatic β cells to alleviate insulin resistance and underlying mechanisms, INS-1 cells were cultured into normal control (N), high glucose (H), high glucose and metformin (H + Met), high glucose and chloroquine (H + CQ), and high glucose and Ex527 (H + Ex527) groups, respectively. Upon 24-hr cultivation, the proliferation and glucose-stimulated insulin secretion (GSIS) of INS-1 cells were determined, and the expression of irisin and other proteins associated with AMPK/SIRT1/PGC-1α signal pathway, autophagy, and apoptosis was evaluated. Compared with the N group, the cells from the H group revealed lower proliferation, GSIS, and expression of irisin and proteins associated with AMPK/SIRT1/PGC-1α signal pathway and autophagy, but higher expression of proteins associated with apoptosis; in contrast, metformin could significantly rescue lower cell proliferation, GSIS, and expression of proteins associated with AMPK/SIRT1/PGC-1α signal pathway and autophagy, as well as irisin, and suppress apoptosis in high-glucose environment. Meanwhile, autophagy inhibitor CQ and SIRT1 inhibitor Ex527 can block above functions of metformin. Therefore, metformin can promote INS-1 cell proliferation, enhance GSIS, and suppress apoptosis by activating AMPK/SIRT1/PGC-1α signal pathway, up-regulating irisin expression, and inducing autophagy in INS-1 cells in high-glucose environment.

AMPK-Targeted Effector Networks in Mycobacterial Infection

AMP-activated protein kinase (AMPK), a key metabolic regulator, plays an essential role in the maintenance of energy balance in response to stress. Tuberculosis (TB), primarily caused by the pathogen Mycobacterium tuberculosis (Mtb), remains one of the most important infectious diseases worldwide, characterized by both high incidence and mortality. Development of new preventive and therapeutic strategies against TB requires a profound understanding of the various host-pathogen interactions that occur during infection. Emerging data suggest that AMPK plays an essential regulatory role in host autophagy, mitochondrial biogenesis, metabolic reprogramming, fatty acid β-oxidation, and the control of pathologic inflammation in macrophages during Mtb infection. As described in this review, recent studies have begun to define the functional properties of AMPK modulators capable of restricting intracellular bacteria and promoting host defenses. Several host defense factors in the context of AMPK activation also participate in autophagic and non-autophagic pathways in a coordinated manner to enhance antimicrobial responses against Mtb infection. A better understanding of these AMPK-targeted effector networks offers significant potential for the development of novel therapeutics for human TB and other infectious diseases.

Multiple Targets of 3-Dehydroxyceanothetric Acid 2-Methyl Ester to Protect Against Cisplatin-Induced Cytotoxicity in Kidney Epithelial LLC-PK1 Cells

Chronic exposure to cisplatin, a potent anticancer drug, causes irreversible kidney damage. In this study, we investigated the protective effect and mechanism of nine lupane- and ceanothane-type triterpenoids isolated from jujube (Ziziphus jujuba Mill., Rhamnaceae) on cisplatin-induced damage to kidney epithelial LLC-PK1 cells via mitogen-activated protein kinase (MAPK) and apoptosis pathways. Cisplatin-induced LLC-PK1 cell death was most significantly reduced following treatment with 3-dehydroxyceanothetric acid 2-methyl ester (3DC2ME). Additionally, apoptotic cell death was significantly reduced. Expression of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and p38 was markedly suppressed by 3DC2ME, indicating inhibition of the MAPK pathway. Treatment with 3DC2ME also significantly reduced expression of active caspase-8 and -3, Bcl-2-associated X protein (Bax), and B cell lymphoma 2 (Bcl-2), indicating the inhibition of apoptosis pathways in the kidneys. We also applied the network pharmacological analysis and identified multiple targets of 3DC2ME related to MAPK signaling pathway and apoptosis.

Dibenzoylmethane ameliorates lipid-induced inflammation and oxidative injury in diabetic nephropathy

Dibenzoylmethane (DBM) is a beta-diketone analog of curcumin. Numerous studies have shown the beneficial effects of curcumin on diabetes, obesity and diabetic complications including diabetic nephropathy. Recently, we investigated the beneficial metabolic effects of DBM on high-fat diet-induced obesity. However, the effects and mechanisms of action of DBM in the kidney are currently unknown. To investigate the renoprotective effects of DBM in type 2 diabetes, we administered DBM (100 mg/kg) orally for 12 weeks to high-fat diet-induced diabetic model mice. We used mouse renal mesangial (MES13) and macrophage (RAW 264.7) cells to examine the mechanism of action of DBM (20 μM). After DBM treatment, the albumin-to-creatinine ratio was significantly decreased compared to that of the high-fat-diet group. Moreover, damaged renal ultra-structures and functions including increased glomerular volume, glomerular basement membrane thickness and inflammatory signals were ameliorated after DBM treatment. Stimulation of MES13 and RAW264.7 cells by palmitate or high-dose glucose with lipopolysaccharides increased inflammatory signals and macrophage migration. However, these changes were reversed by DBM treatment. In addition, DBM inhibited NADPH oxidase 2 and 4 expression and oxidative DNA damage. Collectively, these data suggested that DBM prevented diabetes-induced renal injury through its anti-inflammatory and antioxidant effects.

Epidermal growth factor receptor and podocin predict nephropathy progression in type 2 diabetic patients through interaction with the autophagy influencer ULK-1

AIMS

Diabetic nephropathy (DN) that progress to end stage renal failure is a serious health problem. Autophagy is involved in DN pathogenesis. Finding renal prognostic biomarkers can help in the future renal status prevision. Therefore, the aim of current study was to evaluate and correlate circulating levels of autophagy regulator protein Unc-51-like kinase 1 (ULK-1) with the widely expressed receptor in mammalian kidney; epidermal growth factor receptor (EGFR); and the key functional podocyte protein podocin (PDCN).

METHODS

Serum levels were assessed by ELISA in 72 type 2 diabetic patients classified according to their urinary albumin/creatinine ratio; 19 normoalbuminuric, 37 microalbuminuric and 16 macroalbuminuric patients; age and sex matched with 18 healthy controls.

RESULTS

Microalbuminuria and macroalbuminuria patients exhibited decreased ULK-1, EGFR and PDCN levels. Only EGFR showed lower levels in normoalbuminuria compared with controls. ULK-1 and EGFR were significantly higher in normoalbuminuria compared with microalbuminuria and macroalbuminuria patients. ULK-1, EGFR and PDCN were correlated with each other and with some metabolic parameters.

CONCLUSIONS

ULK-1 with EGFR can predict early impairment in DN while PDCN can highlight progressive DN risk EGFR and PDCN may interact synergistically with ULK-1 in autophagy dysregulation as a pathogenic mechanism of DN induction and progression.

Quercetin alleviates ethanol-induced liver steatosis associated with improvement of lipophagy

Although emerging evidence demonstrated that quercetin could be explored as a potential candidate for the early intervention of alcoholic liver disease (ALD), the exact mechanisms against ethanol-induced hepatic steatosis haven't been fully elucidated. Herein, we investigated the effect of quercetin on liver steatosis caused by chronic-plus-single-binge ethanol feeding, focusing on lipophagy. Adult male mice were pair-fed with liquid diets containing ethanol (28% of total calories) and treated with quercetin for 12 weeks. Chronic-plus-binge ethanol consumption led to lipid droplets accumulation and liver damage as evidenced by histopathological changes, the increased content of triglyceride in serum and liver, and the elevated of serum ALT and AST level, which were greatly attenuated by quercetin. Moreover, quercetin blocked autophagy suppression by chronic-binge ethanol intake as manifested by the morphological improvement of mitochondrial characteristics, the increased number of autolysosome and restoration of autophagy-related protein expression. Furthermore, quercetin promoted lipophagy confirmed by the decreased perilipin 2 (PLIN2) level, activated AMPK activity and increased co-localization of liver LC3II and PLIN2 proteins. Collectively, these findings suggest that regular consumption of dietary quercetin has a role in preventing hepatic steatosis induced by chronic-plus-binge ethanol feeding, which mechanism may associate with the evident regulatory effect of quercetin on lipophagy.