Serum level of the autophagy biomarker Beclin-1 in patients with diabetic kidney disease

Differences in autophagy marker levels at birth in preterm vs. term infants

BACKGROUND

Preterm infants are susceptible to oxidative stress and prone to respiratory diseases. Autophagy is an important defense mechanism against oxidative-stress-induced cell damage and involved in lung development and respiratory morbidity. We hypothesized that autophagy marker levels differ between preterm and term infants.

METHODS

In the prospective Basel-Bern Infant Lung Development (BILD) birth cohort we compared cord blood levels of macroautophagy (Beclin-1, LC3B), selective autophagy (p62) and regulation of autophagy (SIRT1) in 64 preterm and 453 term infants.

RESULTS

Beclin-1 and LC3B did not differ between preterm and term infants. However, p62 was higher (0.37, 95% confidence interval (CI) 0.05;0.69 in log2-transformed level, p = 0.025, padj = 0.050) and SIRT1 lower in preterm infants (-0.55, 95% CI -0.78;-0.31 in log2-transformed level, padj < 0.001). Furthermore, p62 decreased (padj-value for smoothing function was 0.018) and SIRT1 increased (0.10, 95% CI 0.07;0.13 in log2-transformed level, padj < 0.001) with increasing gestational age.

CONCLUSION

Our findings suggest differential levels of key autophagy markers between preterm and term infants. This adds to the knowledge of the sparsely studied field of autophagy mechanisms in preterm infants and might be linked to impaired oxidative stress response, preterm birth, impaired lung development and higher susceptibility to respiratory morbidity in preterm infants.

IMPACT

To the best of our knowledge, this is the first study to investigate autophagy marker levels between human preterm and term infants in a large population-based sample in cord blood plasma This study demonstrates differential levels of key autophagy markers in preterm compared to term infants and an association with gestational age This may be linked to impaired oxidative stress response or developmental aspects and provide bases for future studies investigating the association with respiratory morbidity.

Association between serum beclin 1 level and cardiac valvular calcification in hemodialysis patients

BACKGROUND

Cardiovascular calcification is a pervasive issue throughout chronic kidney disease (CKD) progression. Autophagy, a fundamental cellular process, exerts significant influence on various cardiac pathologies, including arrhythmias, atherosclerosis, heart failure, and notably, valvular, and vascular calcifications. Beclin-1, a crucial eukaryotic protein, plays a major regulatory role in autophagy as part of the phosphatidylinositol-3-kinase (PI3K) complex. Recent evidence suggests a protective role for Beclin-1-mediated autophagy in CKD vascular calcification, raising its potential as a novel therapeutic target in this context.

WE AIMED TO

Investigate the association between serum Beclin 1 levels and the presence of cardiovascular valvular calcification in hemodialysis patients.

RESULTS

This study evaluated a cohort of 102 hemodialysis patients, evenly divided into two groups based on echocardiographic findings. All participants underwent serum Beclin 1 measurement and transthoracic echocardiography. Patients with acute kidney injury, active malignancy, or diabetes were excluded. Our study revealed significant differences between the two groups in terms of: Serum Beclin 1 levels, all parameters of lipid profile, prevalence of ischemic heart disease, serum albumin levels and Total calcium. Echocardiography in Group 1 showed that most cases (60.78%) exhibited mild aortic valve calcification. Additionally, significant relationships were observed between Beclin 1 and: ischemic heart disease (p=0.011) Aortic valve calcification on echocardiography (p < 0.001) Interestingly, lower Beclin 1 levels were associated with more severe valve calcification. A Beclin 1 cutoff value of ≤ 35.5 ng/ml demonstrated the highest sensitivity (98%) and specificity (92%).

CONCLUSION

Our findings suggest that the serum Beclin 1 level could be incorporated into a predictive model for cardiac valvular calcification in hemodialysis patients.

Narrative review investigating the nephroprotective mechanisms of sodium glucose cotransporter type 2 inhibitors in diabetic and nondiabetic patients with chronic kidney disease

Background and aims

Outcome trials using sodium glucose cotransporter type 2 inhibitors have consistently shown their potential to preserve kidney function in diabetic and nondiabetic patients. Several mechanisms have been introduced which may explain the nephroprotective effect of sodium glucose cotransporter type 2 inhibitors beyond lowering blood glucose. This current narrative review has the objective to describe main underlying mechanisms causing a nephroprotective effect and to show similarities as well as differences between proposed mechanisms which can be observed in patients with diabetic and nondiabetic chronic kidney disease.

Methods

We performed a narrative review of the literature on Pubmed and Embase. The research string comprised various combinations of items including "chronic kidney disease", "sodium glucose cotransporter 2 inhibitor" and "mechanisms". We searched for original research and review articles published until march, 2022. The databases were searched independently and the agreements by two authors were jointly obtained.

Results

Sodium glucose cotransporter type 2 inhibitors show systemic, hemodynamic, and metabolic effects. Systemic effects include reduction of blood pressure without compensatory activation of the sympathetic nervous system. Hemodynamic effects include restoration of tubuloglomerular feedback which may improve pathologic hyperfiltration observed in most cases with chronic kidney disease. Current literature indicates that SGLT2i may not improve cortical oxygenation and may reduce medullar oxygenation.

Conclusion

Sodium glucose cotransporter type 2 inhibitors cause nephroprotective effects by several mechanisms. However, several mediators which are involved in the underlying pathophysiology may be different between diabetic and nondiabetic patients.

LncRNA H19: a novel player in the regulation of diabetic kidney disease

Diabetic kidney disease (DKD), one of the most severe complications of diabetes mellitus (DM), has received considerable attention owing to its increasing prevalence and contribution to chronic kidney disease (CKD) and end-stage kidney disease (ESRD). However, the use of drugs targeting DKD remains limited. Recent data suggest that long non-coding RNAs (lncRNAs) play a vital role in the development of DKD. The lncRNA H19 is the first imprinted gene, which is expressed in the embryo and down-regulated at birth, and its role in tumors has long been a subject of controversy, however, in recent years, it has received increasing attention in kidney disease. The LncRNA H19 is engaged in the pathological progression of DKD, including glomerulosclerosis and tubulointerstitial fibrosis via the induction of inflammatory responses, apoptosis, ferroptosis, pyroptosis, autophagy, and oxidative damage. In this review, we highlight the most recent research on the molecular mechanism and regulatory forms of lncRNA H19 in DKD, including epigenetic, post-transcriptional, and post-translational regulation, providing a new predictive marker and therapeutic target for the management of DKD.

The Molecular Mechanism and Therapeutic Application of Autophagy for Urological Disease

Autophagy is a lysosomal degradation process known as autophagic flux, involving the engulfment of damaged proteins and organelles by double-membrane autophagosomes. It comprises microautophagy, chaperone-mediated autophagy (CMA), and macroautophagy. Macroautophagy consists of three stages: induction, autophagosome formation, and autolysosome formation. Atg8-family proteins are valuable for tracking autophagic structures and have been widely utilized for monitoring autophagy. The conversion of LC3 to its lipidated form, LC3-II, served as an indicator of autophagy. Autophagy is implicated in human pathophysiology, such as neurodegeneration, cancer, and immune disorders. Moreover, autophagy impacts urological diseases, such as interstitial cystitis /bladder pain syndrome (IC/BPS), ketamine-induced ulcerative cystitis (KIC), chemotherapy-induced cystitis (CIC), radiation cystitis (RC), erectile dysfunction (ED), bladder outlet obstruction (BOO), prostate cancer, bladder cancer, renal cancer, testicular cancer, and penile cancer. Autophagy plays a dual role in the management of urologic diseases, and the identification of potential biomarkers associated with autophagy is a crucial step towards a deeper understanding of its role in these diseases. Methods for monitoring autophagy include TEM, Western blot, immunofluorescence, flow cytometry, and genetic tools. Autophagosome and autolysosome structures are discerned via TEM. Western blot, immunofluorescence, northern blot, and RT-PCR assess protein/mRNA levels. Luciferase assay tracks flux; GFP-LC3 transgenic mice aid study. Knockdown methods (miRNA and RNAi) offer insights. This article extensively examines autophagy's molecular mechanism, pharmacological regulation, and therapeutic application involvement in urological diseases.

Promising renoprotective effect of gold nanoparticles and dapagliflozin in diabetic nephropathy via targeting miR-192 and miR-21

Diabetic nephropathy (DN) is a worldwide issue that eventually leads to end-stage renal failure, with limited therapeutic options. Prior research has revealed that gold nanoparticles (AuNPs) have a substantial antidiabetic impact. In addition, sodium-glucose cotransporter2 (SGLT2) inhibitors, including dapagliflozin (DAPA), had renoprotective impact on DN. Therefore, this research attempted to determine the potential AuNPs and DAPA impacts in ameliorating experimentally DN induction and the underlying mechanisms focusing on miR-192 and miR-21, correlating them with autophagy, apoptosis, fibrosis, and oxidative stress. Diabetes induction was through a single intraperitoneal streptozotocin (55 mg/kg) injection, and rats with diabetes received AuNPs (2.5 mg/kg/day) as well as DAPA (2 mg/kg/day) for 7 weeks as a treatment. AuNPs and DAPA treatment for 7 weeks substantially alleviated DN. AuNPs and DAPA significantly increased catalase (CAT) activity as well as serum total antioxidant capacity (TAC), along with a substantial decline in malondialdehyde (MDA). AuNPs and DAPA treatment alleviated renal fibrosis as they decreased transforming growth factorß1(TGF-ß1) as well as matrix metalloproteinase-2 (MMP-2) renal expression, decreased apoptosis through alleviating the proapoptotic gene (caspase-3) renal expression and increased the antiapoptotic gene (Bcl-2) renal expression, and increased autophagy as they increased LC-3 as well as Beclin-1 renal expression. Autophagy activation, inhibition of apoptosis, and renal fibrosis could be due to their inhibitory impact on miR-192 and miR-21 renal expression. AuNPs and DAPA have a protective effect on DN in rats by targeting miR-192 and miR-21 and their downstream pathways, including fibrosis, apoptosis, autophagy, and oxidative stress.

Evaluating the Serum Levels of Beclin-1 and Mammalian/Mechanistic Target of Rapamycin (mTOR) in Three Different Professional Categories

BACKGROUND

The possible associations between occupational factors and autophagy - a catabolic process that is evolutionarily conserved and serves as a vital cornerstone in maintaining cellular balance - remain largely unexplored.

OBJECTIVES

We assessed serum levels of beclin-1, a principal effector of autophagy, and the mammalian/mechanistic target of rapamycin (mTOR), a protein recognized for its part in suppressing autophagy, within a group of healthy individuals hailing from three different professional fields, each characterized by its unique working conditions.

METHODS

A total of 60 men were recruited from three distinct occupational categories: airline pilots, construction laborers, and fitness trainers. Each group consisted of 20 subjects who were selected during routine occupational health appointments. Serum levels of beclin-1 and mTOR were measured using commercially available immunoassays and compared among the three categories.

RESULTS

Fitness instructors had the highest concentration of beclin-1 (3.1 ± 0.9 ng/mL). Construction workers followed with a mean of 2.4 ± 0.4 ng/mL, while airline pilots had the lowest levels at 1.9 ± 0.5 ng/mL (one-way analysis of variance, P < 0.001). In terms of mTOR levels, construction workers had the highest concentration (5.9 ± 1.9 ng/mL), followed by airline pilots (4.4 ± 1.7 ng/mL). Fitness instructors, on the other hand, had the lowest mTOR levels (3.5 ± 1.2 ng/mL; one-way analysis of variance, P < 0.001).

CONCLUSIONS

Serum levels of autophagy biomarkers can vary among healthy individuals based on their professional roles. Considering the crucial function autophagy serves in both health and disease, further investigations are crucial to deepen our comprehension of the potential implications of autophagy in the field of occupational medicine.

Identification and analysis of type 2 diabetes-mellitus-associated autophagy-related genes

Introduction

Autophagy, an innate safeguard mechanism for protecting the organism against harmful agents, is implicated in the survival of pancreatic â cells and the development of type 2 diabetes mellitus (T2DM). Potential autophagy-related genes (ARGs) may serve as potential biomarkers for T2DM treatment.

Methods

The GSE25724 dataset was downloaded from the Gene Expression Omnibus (GEO) database, and ARGs were obtained from the Human Autophagy Database. The differentially expressed autophagy-related genes (DEARGs) were screened at the intersection of ARGs and differentially expressed genes (DEGs) between T2DM and non-diabetic islet samples, which were subjected to functional enrichment analyses. A protein-protein interaction (PPI) network was constructed to identify hub DEARGs. Expressions of top 10 DEARGs were validated in human pancreatic â-cell line NES2Y and rat pancreatic INS-1 cells using quantitative reverse transcription polymerase chain reaction (qRT-PCR). Cell viability and insulin secretion were measured after cell transfection with lentiviral vector EIF2AK3 or RB1CC1 into islet cells.

Results

In total, we discovered 1,270 DEGs (266 upregulated and 1,004 downregulated genes) and 30 DEARGs enriched in autophagy- and mitophagy-related pathways. In addition, we identified GAPDH, ITPR1, EIF2AK3, FOXO3, HSPA5, RB1CC1, LAMP2, GABARAPL2, RAB7A, and WIPI1 genes as the hub ARGs. Next, qRT-PCR analysis revealed that expressions of hub DEARGs were consistent with findings from bioinformatics analysis. EIF2AK3, GABARAPL2, HSPA5, LAMP2, and RB1CC1 were both differentially expressed in the two cell types. Overexpression of EIF2AK3 or RB1CC1 promoted cell viability of islet cells and increased the insulin secretion.

Discussion

This study provides potential biomarkers as therapeutic targets for T2DM.

Dysregulated autophagy: A key player in the pathophysiology of type 2 diabetes and its complications

Autophagy is essential in regulating the turnover of macromolecules via removing damaged organelles, misfolded proteins in various tissues, including liver, skeletal muscles, and adipose tissue to maintain the cellular homeostasis. In these tissues, a specific type of autophagy maintains the accumulation of lipid droplets which is directly related to obesity and the development of insulin resistance. It appears to play a protective role in a normal physiological environment by eliminating the invading pathogens, protein aggregates, and damaged organelles and generating energy and new building blocks by recycling the cellular components. Ageing is also a crucial modulator of autophagy process. During stress conditions involving nutrient deficiency, lipids excess, hypoxia etc., autophagy serves as a pro-survival mechanism by recycling the free amino acids to maintain the synthesis of proteins. The dysregulated autophagy has been found in several ageing associated diseases including type 2 diabetes (T2DM), cancer, and neurodegenerative disorders. So, targeting autophagy can be a promising therapeutic strategy against the progression to diabetes related complications. Our article provides a comprehensive outline of understanding of the autophagy process, including its types, mechanisms, regulation, and role in the pathophysiology of T2DM and related complications. We also explored the significance of autophagy in the homeostasis of β-cells, insulin resistance (IR), clearance of protein aggregates such as islet amyloid polypeptide, and various insulin-sensitive tissues. This will further pave the way for developing novel therapeutic strategies for diabetes-related complications.

Klotho's impact on diabetic nephropathy and its emerging connection to diabetic retinopathy

Diabetic nephropathy (DN) is the leading cause of end-stage renal disease worldwide and is a significant burden on healthcare systems. α-klotho (klotho) is a protein known for its anti-aging properties and has been shown to delay the onset of age-related diseases. Soluble klotho is produced by cleavage of the full-length transmembrane protein by a disintegrin and metalloproteases, and it exerts various physiological effects by circulating throughout the body. In type 2 diabetes and its complications DN, a significant decrease in klotho expression has been observed. This reduction in klotho levels may indicate the progression of DN and suggest that klotho may be involved in multiple pathological mechanisms that contribute to the onset and development of DN. This article examines the potential of soluble klotho as a therapeutic agent for DN, with a focus on its ability to impact multiple pathways. These pathways include anti-inflammatory and oxidative stress, anti-fibrotic, endothelial protection, prevention of vascular calcification, regulation of metabolism, maintenance of calcium and phosphate homeostasis, and regulation of cell fate through modulation of autophagy, apoptosis, and pyroptosis pathways. Diabetic retinopathy shares similar pathological mechanisms with DN, and targeting klotho may offer new insights into the prevention and treatment of both conditions. Finally, this review assesses the potential of various drugs used in clinical practice to modulate klotho levels through different mechanisms and their potential to improve DN by impacting klotho levels.

The Effect of Allograft Inflammatory Factor-1 on Inflammation, Oxidative Stress, and Autophagy via miR-34a/ATG4B Pathway in Diabetic Kidney Disease

Increasing evidence suggests that disorders of inflammation, oxidative stress, and autophagy contribute to the pathogenesis of diabetic kidney disease (DKD). This study attempted to clarify the effect of allograft inflammatory factor-1 (AIF-1), miR-34a, and ATG4B on inflammation, oxidative stress, and autophagy in DKD both in vitro and in vivo experiments. In vivo, it was found that the levels of AIF-1, miR-34a, oxidative stress, and inflammatory factors were significantly increased in blood and urine samples of DKD patients and mouse models and correlated with the level of urinary protein. In vitro, it was also found that the expressions of AIF-1, miR-34a, ROS, and inflammatory factors were increased, while ATG4B and other autophagy related proteins were decreased in human renal glomerular endothelial cells (HRGECs) cultured with high concentration glucose medium (30 mmol/L). When AIF-1 gene was overexpressed, the levels of miR-34a, ROS, and inflammatory factors were significantly upregulated, and autophagy-related proteins such as ATG4B were downregulated, while downregulation of AIF-1 gene had the opposite effect. In addition, miR-34a inhibited the expression of ATG4B and autophagy-related proteins and increased the levels of ROS and inflammation. Furthermore, the result of luciferase reporter assay suggested that ATG4B was the target gene of miR-34a. When ATG4B gene was overexpressed, the level of autophagy was upregulated, and inflammatory factors were downregulated. Conversely, when ATG4B gene was inhibited, the level of autophagy was downregulated, and inflammatory factors were upregulated. Then, autophagy inducers inhibited the levels of inflammation and ROS, whereas autophagy inhibitors had the opposite function in HRGECs induced by glucose (30 mmol/L). In conclusion, the above data suggested that AIF-1 regulated the levels of inflammation, oxidative stress, and autophagy in HRGECs via miR-34a/ATG4B pathway to contribute to the pathogenesis of diabetic kidney disease.

Overexpressing STAMP2 attenuates diabetic renal injuries via upregulating autophagy in diabetic rats

Diabetic nephropathy (DN) is one of the most serious and major renal complications of diabetes. Previously, Six-transmembrane Protein of Prostate 2 (STAMP2) was reported to contribute to nutritional stress. The purpose of this study is to investigate whether overexpression of STAMP2 attenuates diabetic renal injuries in DN rats. We induced the DN rat model by high-fat diet and low-dose streptozotocin and evaluated the metabolite and urine albumin/creatinine. Recombinant adeno-associated virus vectors were injected for overexpression of STAMP2. Pathophysiologic and ultrastructure features of DN by histochemical stain and transmission electron microscope, autophagy-related proteins and signaling pathway by western blotting were assessed. We found the expression of STAMP2 was decreased and autophagy was blunted in DN rat kidneys. Overexpressing STAMP2 significantly ameliorated metabolic disturbance, insulin resistance, and specifically restoring diabetic renal injury. Furthermore, overexpressing STAMP2 improved the autophagy deficiency in DN rats, as revealed by changes in the expressions of Beclin1, p62, and LC3. Furthermore, STAMP2 overexpressing promoted autophagy by inhibiting the mTOR and activating the AMPK/SIRT1 signaling pathway. Our results suggested that STAMP2 overexpression attenuated renal injuries via upregulating autophagy in DN rats. STAMP2 overexpressing promoted autophagy may been involved with inhibition of the mTOR/ULK1 and activation of the AMPK/SIRT1 signaling pathway.

Luteolin alleviates inorganic mercury-induced kidney injury via activation of the AMPK/mTOR autophagy pathway

Inorganic mercury is a ubiquitous toxic pollutant in the environment. Exposure to inorganic mercury can cause various poisonous effects, including kidney injury. However, no safe and effective treatment for kidney injury caused by inorganic mercury has been found and used. Luteolin (Lut) possesses various beneficial bioactivities. Here, our research aims to investigate the protective effect of Lut on renal injury induced by mercury chloride (HgCl₂) and identify the underlying autophagy regulation mechanism. Twenty-eight 6-8 weeks old Wistar rats were randomly assigned to four groups: control, HgCl₂, HgCl₂ + Lut, and Lut. We performed the determination of oxidative stress and renal function indicators, histopathological analysis, the terminal deoxynucleotidyl transferase-mediated deoxyuracil nucleoside triphosphate nick-end labeling assay to detect apoptosis, western blot detection of autophagy-related protein levels, and atomic absorption method to detect mercury content. Our results showed that Lut ameliorated oxidative stress, apoptosis and restored the autophagy and renal function caused by HgCl₂ in rats. Concretely, the level of nuclear factor E2-related factor, renal adenosine monophosphate-activated protein kinase (AMPK) expression, and autophagy regulation-related proteins levels were down-regulated, and the mammalian target of rapamycin (mTOR) expression was up-regulated by HgCl₂ treatment. However, Lut treatment reversed the above changes. Notably, Lut reduced the accumulation of HgCl₂ in the kidneys and promoted the excretion of HgCl₂ through urine. Collectively, our results demonstrate that Lut can attenuate inorganic mercury-induced renal injury via activating the AMPK/mTOR autophagy pathway. Therefore, Lut may be a potential biological medicine to protect against renal damage induced by HgCl₂.

Beclin1 circulating level as predictor of carotid intima-media thickness in patients with type 2 diabetes mellitus

Type 2 diabetes (T2DM) represents a major risk factor for atherosclerosis that is the underlying cause of most cardiovascular diseases. Identifying reliable predictive biomarkers are needed to improve the long-term outcome in diabetic patients. Autophagy plays a pivotal role in the pathogenesis of atherosclerosis. Beclin1 is a key regulatory protein of autophagy and has been localized in human atherosclerotic lesions. However, the relation of serum level of Beclin1 and atherosclerosis in patients with diabetes has not been clarified yet.To assess the relationship between serum level of Beclin1 and carotid intima-media thickness (CIMT) in patients with T2DM.In this case-control study participants were recruited from tertiary care hospitals in Egypt. The study enrolled 50 patients with T2DM and 25 healthy subjects between January, 2019 and January, 2020. Age, gender, and body mass index were recorded for all subjects. Laboratory works up including glycated hemoglobin, lipid panel, and serum Beclin1 (by enzyme-linked immunosorbent assay) were measured. CIMT was assessed by color Doppler. Comparisons between patients and the control group were done using analysis of variance and Chi-square test. Correlations between CIMT and Beclin1 level and different variables were done using the Pearson correlation coefficient. Receiver operator characteristic curve was constructed with the area under curve analysis performed to detect the best cutoff value of Beclin1 for detection of CIMT > 0.05 cm.The level of Beclin1 in the patient group was significantly lower compared with that in the control group (1.28 ± 0.51 vs 5.24 ± 1.22 ng/dL, P < .001). The level of Beclin1 apparently decreased in the higher CIMT group in T2DM patients. Serum Beclin1 levels were negatively correlated with CIMT (r = -0.762; P < .001), low-density lipoprotein-cholesterol (r = -0.283; P = .04), and triglycerides (r = -0.350; P = .01) but positively correlated with high-density lipoprotein-cholesterol (r = 0.491; P < .001) in patients with T2DM. Beclin1 level >2.2 ng/dL was an accurate predictor of CIMT >0.05 cm with an area under the curve value of 0.997, 93.9% sensitivity, and 100% specificity.Beclin1 levels were negatively correlated with atherosclerotic load in patients with T2DM and it may be considered as a promising diagnostic and therapeutic target.

Protective potential of cerium oxide nanoparticles in diabetes mellitus

BACKGROUND

Diabetes mellitus (DM) is a non-communicable metabolic disease which is closely related to excessive oxidative stress after constant exposure to high plasma glucose. Although the current antidiabetic medications are effective in lowering blood glucose, these medications do not prevent or reverse the disease progression. Thus, there is a crucial need to explore new therapeutic interventions that could address this shortcoming. As cerium oxide nanoparticles (CONPs) possess antioxidant property, this agent may be used as a treatment option for the management of DM.

PURPOSE

This review aims to provide a critical evaluation of the pharmacological and antidiabetic effects of CONPs in cell and animal models. The roles of CONPs in attenuating DM complications are also presented in this report.

METHODS

We conducted a literature search in the PubMed database using the keywords "cerium oxide", "cerous oxide", "ceria", "nanoceria", and "diabetes" from inception to December 2020. The inclusion criteria were primary source articles that investigated the role of CONPs in DM and diabetic complications.

RESULTS

We identified 47 articles from the initial search. After the thorough screening, only 31 articles were included in this study. We found that CONPs can attenuate parameters that are related to DM and diabetic complications in various animals and cell culture models.

CONCLUSION

CONPs could potentially be used in the treatment of those with DM and complications caused by the disease.

Beclin-1, an autophagy-related protein, is associated with the disease severity of COVID-19

Aims

Coronavirus disease 2019 (COVID-19), which is a highly contagious disease, is an ongoing outbreak worldwide with high morbidity and mortality. The approaches targeting the autophagy processes might have promising diagnostic and therapeutic values against Coronavirus infection. Here, we aimed to investigate the relationship of Beclin-1 (BECN1), an autophagy-related protein, with blood parameters and the clinical severity in patients with COVID-19.

Materials and methods

We enrolled 108 patients with COVID-19 and 21 healthy controls in this study, from September 2020 to January 2021 and divided all patients into two groups according to the severity of the disease: The non-severe group and the severe group. BECN1 levels and blood parameters were measured with Enzyme-Linked Absorbent Assay and routine techniques, respectively.

Key findings

Serum BECN1 levels were increased in patients with COVID-19 compared to the healthy controls, and its concentrations were significantly higher in the severe group than in the non-severe group (p < 0.001). BECN1 levels showed a significantly positive correlation with coagulation markers such as D-dimer and Fibrinogen (FIB) and inflammation markers such as C-reactive protein (CRP), Procalcitonin (PCT), Ferritin and biochemical markers such as Blood urea nitrogen and Lactate dehydrogenase (p < 0.001). We detected that areas under the ROC curve for BECN1, D-dimer, FIB, PCT, CRP and Ferritin were 0.8662, 0.9110, 0.8278, 0.9996 and 0.9284, respectively (p < 0.0001).

Significance

BECN1 may serve as a predictive biomarker in evaluating the disease severity of COVID-19. Our data suggest that BECN1 mediated-autophagy modulation might have a promising value in improving the clinical outcomes of COVID-19.

Extracellular SQSTM1 mediates bacterial septic death in mice through insulin receptor signalling

Sepsis is the most common cause of death for patients in intensive care worldwide due to a dysregulated host response to infection. Here, we investigate the role of sequestosome-1 (SQSTM1/p62), an autophagy receptor that functions as a regulator of innate immunity, in sepsis. We find that lipopolysaccharide elicits gasdermin D-dependent pyroptosis to enable passive SQSTM1 release from macrophages and monocytes, whereas transmembrane protein 173-dependent TANK-binding kinase 1 activation results in the phosphorylation of SQSTM1 at Ser403 and subsequent SQSTM1 secretion from macrophages and monocytes. Moreover, extracellular SQSTM1 binds to insulin receptor, which in turn activates a nuclear factor kappa B-dependent metabolic pathway, leading to aerobic glycolysis and polarization of macrophages. Intraperitoneal injection of anti-SQSTM1-neutralizing monoclonal antibodies or conditional depletion of Insr in myeloid cells using the Cre-loxP system protects mice from lethal sepsis (caecal ligation and puncture or infection by Escherichia coli or Streptococcus pneumoniae) and endotoxaemia. We also report that circulating SQSTM1 and the messenger RNA expression levels of SQSTM1 and INSR in peripheral blood mononuclear cells are related to the severity of sepsis in 40 patients. Thus, extracellular SQSTM1 has a pathological role in sepsis and could be targeted to develop therapies for sepsis.

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.

Matrine inhibits cell growth, migration, invasion and promotes autophagy in hepatocellular carcinoma by regulation of circ_0027345/miR-345-5p/HOXD3 axis

Background

Matrine has been reported to exert anti-tumor effects in multiple types of cancers containing hepatocellular carcinoma (HCC). However, the anti-tumor molecular mechanisms of matrine in HCC is still not fully revealed.

Methods

Cell viability, apoptosis, cycle, migration and invasion were determined by Cell counting kit-8 (CCK-8), Flow cytometry and Transwell assays, respectively. Levels of all protein were analyzed by western blot analysis. The levels of circular RNA_0027345 (circ_0027345), microRNA-345-5p (miR-345-5p) and homeobox-containingD3 (HOXD3) were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The interaction between circ_0027345 and circ_0027345 was identified using dual-luciferase reporter assay. The mouse xenograft model was constructed to explore the effect of matrine on tumor growth in vivo.

Results

Matrine suppressed cell growth, migration and invasion, while promoted apoptosis and autophagy in HCC cells. Matrine down-regulated the levels of circ_0027345 and HOXD3, and up-regulated miR-345-5p expression. Besides, circ_0027345 overexpression could reverse the inhibitory effect of matrine on cell progression. As the target gene of circ_0027345, miR-345-5p elevation counteracted the promotion effect of circ_0027345 overexpression on development of HCC cells. Moreover, miR-345-5p knockdown could facilitate cell growth, migration, invasion and repress cell apoptosis and autophagy by targeting HOXD3. Meanwhile, matrine restrained tumor growth of HCC by regulating circ_0027345/miR-345-5p/HOXD3 axis in vivo.

Conclusion

Matrine inhibited cell development and tumorigenesis in HCC by increasing miR-345-5p and decreasing circ_0027345 and HOXD3.

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.

Assessing Autophagy in Archived Tissue or How to Capture Autophagic Flux from a Tissue Snapshot

Autophagy is a highly conserved degradation mechanism that is essential for maintaining cellular homeostasis. In human disease, autophagy pathways are frequently deregulated and there is immense interest in targeting autophagy for therapeutic approaches. Accordingly, there is a need to determine autophagic activity in human tissues, an endeavor that is hampered by the fact that autophagy is characterized by the flux of substrates whereas histology informs only about amounts and localization of substrates and regulators at a single timepoint. Despite this challenging task, considerable progress in establishing markers of autophagy has been made in recent years. The importance of establishing clear-cut autophagy markers that can be used for tissue analysis cannot be underestimated. In this review, we attempt to summarize known techniques to quantify autophagy in human tissue and their drawbacks. Furthermore, we provide some recommendations that should be taken into consideration to improve the reliability and the interpretation of autophagy biomarkers in human tissue samples.

Curcumin Inhibited Podocyte Cell Apoptosis and Accelerated Cell Autophagy in Diabetic Nephropathy via Regulating Beclin1/UVRAG/Bcl2

INTRODUCTION

Curcumin has various biological properties including being anti-inflammatory and antidiabetic. Podocyte apoptosis and autophagy dysfunction have been found to be responsible for the development of diabetic nephropathy (DN). Thus, the aim of the study was to investigate the effects of curcumin on the podocyte apoptosis and autophagy in DN and clarify its potential mechanisms.

METHODS

The mice with DN induced by injection of streptozotocin were treated with curcumin by gavage at a dose of 200 mg/kg/day for 8 weeks. The serum lipid levels were detected by total cholesterol (TC) and triglyceride (TG) kits at different time points. Renal damage was assessed by detecting urine albumin, serum creatinine (Scr), HE staining and PAS staining. The renal impairment was detected by immunohistochemical staining and TUNEL staining. Western blot assay tested the expression of autophagy-related and apoptotic-related proteins in vivo and vitro. The viabilities and apoptosis of MPC5 cells exposed to high glucose (HG) or curcumin were respectively detected by CCK-8 assay and flow cytometry.

RESULTS

The results showed that curcumin significantly decreased the progress of DN possibly via increasing autophagy and inhibiting apoptosis of renal cell in DN mice. Besides, podocyte marker proteins (podocalyxin and nephrin) were markedly increased in DN mice by curcumin treatment. The autophagy-related proteins LC3, p62, Beclin1, UVRAG and ATG5 were significantly affected in DN mice by curcumin, along with reducing expression of pro-apoptotic protein Bax and caspase-3 and increasing anti-apoptotic protein Bcl-2. In vitro, curcumin increased the viabilities and inhibited apoptosis of MPC5 cells exposed to high glucose (HG). In addition, the podocyte autophagy was enhanced partly via regulating beclin1/UVRAG.

DISCUSSION

Together, the results showed that curcumin inhibited podocyte apoptosis and accelerated cell autophagy via regulating Beclin1/UVRAG/Bcl2. Thus, the study showed that curcumin exerted significantly protective effects in DN.

Autophagy in Kidney Disease

Autophagy is a cellular homeostatic program for the turnover of cellular organelles and proteins, in which double-membraned vesicles (autophagosomes) sequester cytoplasmic cargos, which are subsequently delivered to the lysosome for degradation. Emerging evidence implicates autophagy as an important modulator of human disease. Macroautophagy and selective autophagy (e.g., mitophagy, aggrephagy) can influence cellular processes, including cell death, inflammation, and immune responses, and thereby exert both adaptive and maladaptive roles in disease pathogenesis. Autophagy has been implicated in acute kidney injury, which can arise in response to nephrotoxins, sepsis, and ischemia/reperfusion, and in chronic kidney diseases. The latter includes comorbidities of diabetes and recent evidence for chronic obstructive pulmonary disease-associated kidney injury. Roles of autophagy in polycystic kidney disease and kidney cancer have also been described. Targeting the autophagy pathway may have therapeutic benefit in the treatment of kidney disorders.

Chinese Herbal Medicine in Ameliorating Diabetic Kidney Disease via Activating Autophagy

Diabetic kidney disease (DKD), a leading cause of end-stage renal disease (ESRD), has become a serious public health problem worldwide and lacks effective therapies due to its complex pathogenesis. Recent studies suggested defective autophagy involved in the pathogenesis and progression of DKD. Chinese herbal medicine, as an emerging option for the treatment of DKD, could improve diabetic kidney injury by activating autophagy. In this review, we briefly summarize underlying mechanisms of autophagy dysregulation in DKD, including AMP-activated protein kinase (AMPK), the mechanistic target of rapamycin (mTOR), and the sirtuin (Sirt) pathways, and we particularly concentrate on the current status of Chinese herbal medicine treating DKD by regulating autophagy. The advances in our understanding regarding the treatment of DKD via regulating autophagy with Chinese herbal medicine will enhance the clinical application of Chinese medicine as well as discovery of novel therapeutic agents for diabetic patients.