Exacerbation of diabetic cardiac hypertrophy in OVE26 mice by angiotensin II is associated with JNK/c-Jun/miR-221-mediated autophagy inhibition

The receptor for advanced glycation end products and its ligands' expression in OVE26 diabetic sciatic nerve during the development of length-dependent neuropathy

Type 1 diabetes (T1D) may affect the peripheral nervous system and alter the expression of proteins contributing to inflammation and cellular cytoskeleton dysfunction, in most cases leading to the development of diabetic length-dependent neuropathy (DLDN). In the present study, we performed immunohistochemistry (IHC) to probe the expression of the receptor for advanced glycation end products (RAGE); its key ligands, high-mobility group box 1 (HMGB1), S100 calcium-binding protein B (S100B), and carboxymethyl-lysine (CML - advanced glycation end products (AGE)); and its cytoplasmic tail-binding partner, diaphanous related formin 1 (DIAPH1) and associated molecules, beta-actin (ACTB) and profilin 1 (PFN1) proteins in sciatic nerves harvested from seven-month old FVB/OVE26 mice with genetically-mediated T1D. We found that the amount of RAGE, HMGB1, and S100B proteins was elevated in diabetic vs the non-diabetic groups, while the amount of DIAPH1, ACTB, as well as PFN1 proteins did not differ between these groups. Moreover, our data revealed linear dependence between RAGE and HMGB1 proteins. Interaction criss-cross of selected sets of proteins in the sciatic nerve revealed that there were connected in a singular network. Our results indicate that T1D may alter expression patterns of RAGE axis proteins and thus contribute to DLDN.

Exploring the role of non-coding RNAs in autophagy

As a self-degradative mechanism, macroautophagy/autophagy has a role in the maintenance of energy homeostasis during critical periods in the development of cells. It also controls cellular damage through the eradication of damaged proteins and organelles. This process is accomplished by tens of ATG (autophagy-related) proteins. Recent studies have shown the involvement of non-coding RNAs in the regulation of autophagy. These transcripts mostly modulate the expression of ATG genes. Both long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) have been shown to modulate the autophagy mechanism. Levels of several lncRNAs and miRNAs are altered in this process. In the present review, we discuss the role of lncRNAs and miRNAs in the regulation of autophagy in diverse contexts such as cancer, deep vein thrombosis, spinal cord injury, diabetes and its complications, acute myocardial infarction, osteoarthritis, pre-eclampsia and epilepsy.Abbreviations: AMI: acute myocardial infarction; ATG: autophagy-related; lncRNA: long non-coding RNA; miRNA: microRNA.

Autophagy in the diabetic heart: A potential pharmacotherapeutic target in diabetic cardiomyopathy

Association of diabetes with an elevated risk of cardiac failure has been clinically evident. Diabetes potentiates diastolic and systolic cardiac failure following the myocardial infarction that produces the cardiac muscle-specific microvascular complication, clinically termed as diabetic cardiomyopathy. Elevated susceptibility of diabetic cardiomyopathy is primarily caused by the generation of free radicals in the hyperglycemic milieu, compromising the myocardial contractility and normal cardiac functions with increasing redox insult, impaired mitochondria, damaged organelles, apoptosis, and cardiomyocytes fibrosis. Autophagy is essentially involved in the recycling/clearing the damaged organelles, cytoplasmic contents, and aggregates, which are frequently produced in cardiomyocytes. Although autophagy plays a vital role in maintaining the cellular homeostasis in diligent cardiac tissues, this process is frequently impaired in the diabetic heart. Given its clinical significance, accumulating evidence largely showed the functional aspects of autophagy in diabetic cardiomyopathy, elucidating its intricate protective and pathogenic outcomes. However, etiology and molecular readouts of these contrary autophagy activities in diabetic cardiomyopathy are not yet comprehensively assessed and translated. In this review, we attempted to assess the role of autophagy and its adaptations in the diabetic heart. To delineate the molecular consequences of these events, we provided detailed insights into the autophagy regulation pieces of machinery including the mTOR/AMPK, TFEB/ZNSCAN3, FOXOs, SIRTs, PINK1/Parkin, Nrf2, miRNAs, and others in the diabetic cardiomyopathy. Given the clinical significance of autophagy in the diabetic heart, we further discussed the potential pharmacotherapeutic strategies towards targeting autophagy. Taken together, the present report meticulously assessed autophagy, its adaptations, and molecular regulations in diabetic cardiomyopathy and reviewed the current autophagy-targeting strategies.

Interaction between non-coding RNAs and JNK in human disorders

Jun N-terminal Kinase (JNK) signaling pathway is a conserved cascade among species with particular roles in diverse processes during embryogenesis and normal life. These kinases regulate functions of neurons and the immune system by affecting the expression of genes, modulating the arrangement of cytoskeletal proteins, and regulating apoptosis/survival pathways. They are also involved in carcinogenesis. Several miRNAs and lncRNAs have a functional relationship with JNKs. This interaction contributes to the pathogenesis of traumatic brain injury, ulcerative colitis, hepatic ischemia/ reperfusion injury, acute myocardial infarction, and a number of other disorders. Lung cancer, hepatocellular carcinoma, gall bladder cancer, melanoma, and colon cancer are among malignant conditions in which JNK-related miRNAs/ lncRNAs contribute. The current review aims at depicting the functional interaction between JNKs and lncRNAs/ miRNAs and describing the role of these regulatory transcripts in the pathobiology of human disorders.

Nutraceutical Targeting of Inflammation-Modulating microRNAs in Severe Forms of COVID-19: A Novel Approach to Prevent the Cytokine Storm

The coronavirus disease 2019 (COVID-19) pandemic has become the number one health problem worldwide. As of August 2020, it has affected more than 18 million humans and caused over 700,000 deaths worldwide. COVID-19 is an infectious disease that can lead to severe acute respiratory syndrome. Under certain circumstances, the viral infection leads to excessive and uncontrolled inflammatory response, which is associated with the massive release of inflammatory cytokines in pulmonary alveolar structures. This phenomenon has been referred to as the “cytokine storm,” and it is closely linked to lung injury, acute respiratory syndrome and mortality. Unfortunately, there is currently no vaccine available to prevent the infection, and no effective treatment is available to reduce the mortality associated with the severe form of the disease. The cytokine storm associate with COVID-19 shows similarities with those observed in other pathologies such as sepsis, acute respiratory distress syndrome, acute lung injury and other viral infection including severe cases of influenza. However, the specific mechanisms that cause and modulate the cytokine storm in the different conditions remain to be determined. micro-RNAs are important regulators of gene expression, including key inflammatory cytokines involved in the massive recruitment of immune cells to the lungs such as IL1β, IL6, and TNFα. In recent years, it has been shown that nutraceutical agents can modulate the expression of miRs involved in the regulation of cytokines in various inflammatory diseases. Here we review the potential role of inflammatory-regulating-miRs in the cytokine storm associated with COVID-19, and propose that nutraceutical agents may represent a supportive therapeutic approach to modulate dysregulated miRs in this condition, providing benefits in severe respiratory diseases.

Phosphorylation Modifications Regulating Cardiac Protein Quality Control Mechanisms

Many forms of cardiac disease, including heart failure, present with inadequate protein quality control (PQC). Pathological conditions often involve impaired removal of terminally misfolded proteins. This results in the formation of large protein aggregates, which further reduce cellular viability and cardiac function. Cardiomyocytes have an intricately collaborative PQC system to minimize cellular proteotoxicity. Increased expression of chaperones or enhanced clearance of misfolded proteins either by the proteasome or lysosome has been demonstrated to attenuate disease pathogenesis, whereas reduced PQC exacerbates pathogenesis. Recent studies have revealed that phosphorylation of key proteins has a potent regulatory role, both promoting and hindering the PQC machinery. This review highlights the recent advances in phosphorylations regulating PQC, the impact in cardiac pathology, and the therapeutic opportunities presented by harnessing these modifications.

Cellular Protein Quality Control in Diabetic Cardiomyopathy: From Bench to Bedside

Heart failure is a serious comorbidity and the most common cause of mortality in diabetes patients. Diabetic cardiomyopathy (DCM) features impaired cellular structure and function, culminating in heart failure; however, there is a dearth of specific clinical therapy for treating DCM. Protein homeostasis is pivotal for the maintenance of cellular viability under physiological and pathological conditions, particularly in the irreplaceable cardiomyocytes; therefore, it is tightly regulated by a protein quality control (PQC) system. Three evolutionarily conserved molecular processes, the unfolded protein response (UPR), the ubiquitin-proteasome system (UPS), and autophagy, enhance protein turnover and preserve protein homeostasis by suppressing protein translation, degrading misfolded or unfolded proteins in cytosol or organelles, disposing of damaged and toxic proteins, recycling essential amino acids, and eliminating insoluble protein aggregates. In response to increased cellular protein demand under pathological insults, including the diabetic condition, a coordinated PQC system retains cardiac protein homeostasis and heart performance, on the contrary, inappropriate PQC function exaggerates cardiac proteotoxicity with subsequent heart dysfunction. Further investigation of the PQC mechanisms in diabetes propels a more comprehensive understanding of the molecular pathogenesis of DCM and opens new prospective treatment strategies for heart disease and heart failure in diabetes patients. In this review, the function and regulation of cardiac PQC machinery in diabetes mellitus, and the therapeutic potential for the diabetic heart are discussed.

Mouse Models of Heart Failure with Preserved or Reduced Ejection Fraction

Heart failure (HF) is a chronic, complex condition with increasing incidence worldwide, necessitating the development of novel therapeutic strategies. This has led to the current clinical strategies, which only treat symptoms of HF without addressing the underlying causes. Multiple animal models have been developed in an attempt to recreate the chronic HF phenotype that arises following a variety of myocardial injuries. Although significant strides have been made in HF research, an understanding of more specific mechanisms will require distinguishing models that resemble HF with preserved ejection fraction (HFpEF) from those with reduced ejection fraction (HFrEF). Therefore, current mouse models of HF need to be re-assessed to determine which of them most closely recapitulate the specific etiology of HF being studied. This will allow for the development of therapies targeted specifically at HFpEF or HFrEF. This review will summarize the commonly used mouse models of HF and discuss which aspect of human HF each model replicates, focusing on whether HFpEF or HFrEF is induced, to allow better investigation into pathophysiological mechanisms and treatment strategies.

Mst1 knockdown alleviates cardiac lipotoxicity and inhibits the development of diabetic cardiomyopathy in db/db mice

Diabetic cardiomyopathy (DCM) accounts for increasing deaths of diabetic patients, and effective therapeutic targets are urgently needed. Myocardial lipotoxicity, which is caused by cardiac non-oxidative metabolic fatty acids and cardiotoxic fatty acid metabolites accumulation, has gained more attention to explain the increasing prevalence of DCM. However, whether mammalian Ste20-like kinase 1 (Mst1) plays a role in lipotoxicity in type 2 diabetes-induced cardiomyopathy has not yet been illustrated. Here, we found that Mst1 expression was elevated transcriptionally in the hearts of type 2 diabetes mellitus mice and palmitic acid-treated neonatal rat ventricular myocytes. Adeno-associated virus 9 (AAV9)-mediated Mst1 silencing in db/db mouse hearts significantly alleviated cardiac dysfunction and fibrosis. Notably, Mst1 knockdown in db/db mouse hearts decreased lipotoxic apoptosis and inflammatory response. Mst1 knockdown exerted protective effects through inactivation of MAPK/ERK kinase kinase 1 (MEKK1)/c-Jun N-terminal kinase (JNK) signaling pathway. Moreover, lipotoxicity induced Mst1 expression through promoting the binding of forkhead box O3 (FoxO3) and Mst1 promoter. Conclusively, we elucidated for the first time that Mst1 expression is regulated by FOXO3 under lipotoxicity stimulation and downregulation of Mst1 protects db/db mice from lipotoxic cardiac injury through MEKK1/JNK signaling inhibition, indicating that Mst1 abrogation may be a potential treatment strategy for DCM in type 2 diabetic patients.

Involvement of phosphatase and tensin homolog-induced putative kinase 1/Parkin-mediated autophagy in angiotensin II-induced cardiac hypertrophy in C57BL/6 mice

Objective

To study the role of autophagy in angiotensin II-induced cardiac hypertrophy in C57BL/6 mice.

Methods

We randomly assigned 10 C57BL/6 mice into the control and angiotensin II (Ang II) groups (n = 5 in each group). Ang II group mice were injected with Ang II (3 mg/kg/day). Cardiac structure, myocardial pathological changes, mitochondrial structure, autophagosomes, mitochondrial membrane potential (MMP), and myocardial apoptosis were examined. Phosphatase and tensin homolog (PTEN)-induced putative kinase 1 (PINK1), Parkin, and microtubule-associated protein1A/1B-light chain 3 (LC3) II protein expression levels and mRNA expression of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) were examined.

Results

The heart weight/body weight ratio, posterior wall of the left ventricle, myocardial apoptosis (%), relative number of autophagosomes, ANP and BNP mRNA levels, and PINK1, Parkin, and LC3 II protein levels were significantly higher in the Ang II group than in the control group. The MMP and left ventricular ejection fraction were significantly lower in the Ang II group than in the control group. There was disordered arrangement of cardiomyocytes and mitochondria, and obvious mitochondrial swelling, cardiomyocyte hypertrophy, and fibrosis in the Ang II group.

Conclusion

PINK1/PARKIN-mediated autophagy is involved in Ang II-induced cardiac hypertrophy by affecting myocardial apoptosis and mitochondrial function.

Sex differences in progression of diabetic nephropathy in OVE26 type 1 diabetic mice

AIMS

OVE26 mice (FVB background), genetically overexpressing calmodulin in pancreatic beta cells, develop early onset type 1 diabetes, leading to progressive diabetic nephropathy (DN), with features of established human DN. The role of gender in characteristics of renal lesions has remained unexplored.

METHODS

Male and female OVE26 mice were compared to age and sex matched wild-type, nondiabetic FVB mice at ages of 4, 12, 24 and 36 weeks. Nephropathy was examined by measuring urine albumin-to-creatinine ratio, histopathology, expression of pathological markers and immunochemistry in the same cohort of mice.

RESULTS

Progression of diabetic kidney disease was evident first in the OVE26 glomerulus, initially as mesangial matrix expansion at 4 weeks followed by loss of podocytes, glomerular volume expansion and severe albuminuria at 12 weeks. Tubule dilation and initiation of interstitial fibrosis did not become significant until 24 weeks. T-lymphocyte infiltration into the renal parenchyma appeared at 36 weeks. OVE26 female mice developed more advanced DN than male OVE26 mice, such as more severe albuminuria, greater podocyte loss, additional fibrosis and significantly more inflammatory cell infiltration. The female OVE26 mice had lowest level of plasma estradiol in all 36 weeks old mice, as well as renal estrogen receptors.

CONCLUSIONS

This demonstration of the role of gender, combined with the detailed characterization of DN progression illustrates the value of OVE26 mice for understanding gender effects on DN and provides the basis for researchers to better select the age and sex of OVE26 mice in future studies of type 1 DN.

RESEARCH IN CONTEXT

What is already known about this subject? What is the key question? What are the new findings? How might this impact on clinical practice in the foreseeable future?

Hepatic functional and pathological changes of type 1 diabetic mice in growing and maturation time

To detect the changes in the liver function in both male and female OVE26 mice from young to adults for better understanding of type 1 diabetes‐induced hepatic changes, OVE26 mice and wild‐type FVB mice were raised in the same environment without any intervention, and then killed at 4, 12, 24 and 36 weeks for examining liver's general properties, including pathogenic and molecular changes. The influence of diabetes on the bodyweight of male and female mice was different. Both male and female OVE26 mice did not obtain serious liver injury or non‐alcoholic fatty liver disease, manifested by mild elevation of plasma alanine transaminase, and less liver lipid content along with significantly suppressed lipid synthesis. Uncontrolled diabetes also did not cause hepatic glycogen accumulation in OVE26 mice after 4 weeks. Oxidative stress test showed no change in lipid peroxidation, but increased protein oxidation. Changed endoplasmic reticulum stress and apoptosis along with increased antioxidant capacity was observed in OVE26 mice. In conclusion, uncontrolled type 1 diabetes did not cause hepatic lipid deposition most likely because of reduced lipids synthesis in response to insulin deficiency. Enhanced antioxidant capacity might not only prevent the occurrence of severe acute liver injury but also the self‐renewal, leading to liver dysfunction.

RETRACTED: Quercetin ameliorates lipopolysaccharide-caused inflammatory damage via down-regulation of miR-221 in WI-38 cells

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. Given the comments of Dr Elisabeth Bik regarding this article “… the Western blot bands in all 400+ papers are all very regularly spaced and have a smooth appearance in the shape of a dumbbell or tadpole, without any of the usual smudges or stains. All bands are placed on similar looking backgrounds, suggesting they were copy/pasted from other sources, or computer generated”, the journal requested the authors to provide the raw data. However, the authors were not able to fulfil this request and therefore the Editor-in-Chief decided to retract the article.

A RNA-Seq Analysis to Describe the Boar Sperm Transcriptome and Its Seasonal Changes

Understanding the molecular basis of cell function and ultimate phenotypes is crucial for the development of biological markers. With this aim, several RNA-seq studies have been devoted to the characterization of the transcriptome of ejaculated spermatozoa in relation to sperm quality and fertility. Semen quality follows a seasonal pattern and decays in the summer months in several animal species. The aim of this study was to deeply profile the transcriptome of the boar sperm and to evaluate its seasonal changes. We sequenced the total and the short fractions of the sperm RNA from 10 Pietrain boars, 5 collected in summer and 5 five sampled in winter, and identified a complex and rich transcriptome with 4,436 coding genes of moderate to high abundance. Transcript fragmentation was high but less obvious in genes related to spermatogenesis, chromatin compaction and fertility. Short non-coding RNAs mostly included piwi-interacting RNAs, transfer RNAs and microRNAs. We also compared the transcriptome of the summer and the winter ejaculates and identified 34 coding genes and 7 microRNAs with a significantly distinct distribution. These genes were mostly related to oxidative stress, DNA damage and autophagy. This is the deepest characterization of the boar sperm transcriptome and the first study linking the transcriptome and the seasonal variability of semen quality in animals. The annotation described here can be used as a reference for the identification of markers of sperm quality in pigs.

AAV-Mig-6 Increase the Efficacy of TAE in VX2 Rabbit Model, Is Associated With JNK Mediated Autophagy

The characterization of high recurrence rate of HCC after TAE provides insights into persistent issues surrounding the role of adjunct therapies administered with TAE. As a regulator of the HER family, Mig-6 is down-regulated in HCC and predicts the prognosis of HCC. In this study, we found up-regulation the expression of Mig-6 enhances autophagy in HCC cells. This function of Mig-6 is related to the activation of the JNK pathway. Next AAV-9 encoding Mitogen inducible gene 6 (Mig-6) was delivered into VX2 liver transplant tumor of rabbits by using hepatic artery catheter. Wild-type AAV is not associated with any human or animal disease and has very low immunogenicity. There are over 100 different AAV serotypes that vary in the amino acid sequence of their capsid protein. We also describe a novel combination therapy coupling AAV-Mig-6 and TAE in a rabbit model resulted in a growth rate decrease in tumor compared with TAE alone. Furthermore, we show that the changes of LC3b and p62, as well as the p-JNK were consistent with changes in vitro experiments. These results suggest that Mig-6 efficiently inhibits tumor progression in vivo. Our findings suggest that Mig-6 induced autophagy inhibition may become a necessary target for adjunct therapy in TAE.

Serum microRNA-221 as a biomarker for diabetic retinopathy in patients associated with type 2 diabetes

AIM

To investigate the candidate microRNA (miRNA), miR-221 as a novel biomarker for diabetic retinopathy (DR) in patients associated with type 2 diabetes (T2D).

METHODS

The subjects involved were divided into four groups: healthy control (HC), no diabetic retinopathy (NDR), non-proliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR) group. Serum miR-221 was validated by real-time quantitative reverse-transcription polymerase chain reaction (qRT-PCR). Also, serum angiotensin II (Ang II) and vascular endothelial growth factor (VEGF) were examined by enzyme-linked immunosorbent assay. In addition, receiver operating characteristic (ROC) curve was performed to explore the diagnostic accuracy of miR-221, Ang II and VEGF for DR in patients with T2D. Spearman's rank correlation coefficient was executed to estimate the correlations of serum miR-221 with metabolic parameters and serum markers in patients with T2D.

RESULTS

Primarily, serum miR-221, Ang II and VEGF were increased significantly in T2D patients compared to HC participant respectively, and progressive up-regulated in NDR, NPDR and PDR groups (P<0.001). Additionally, miR-221 in serum was remarkably positively correlated with metabolic parameters such as glycated hemoglobin (r=0.310, P=0.002) and homeostasis model assessment for insulin resistance (r=0.413, P<0.001), as well as serum markers for instance Ang II (r=0.667, P<0.001) and VEGF (r=0.499, P<0.001). Furthermore, serum miR-221 (AUC, 0.894; 95%CI, 0.833-0.955; P<0.001), Ang II (AUC, 0.888; 95%CI, 0.828-0.949; P<0.001) and VEGF (AUC, 0.785; 95%CI, 0.695-0.875; P<0.001) had evidently diagnostic efficiency in DR, and miR-221 is the most effective among them.

CONCLUSION

Serum miR-221 as a potential biomarker could be related to not only occurrence but also progression for DR in patients with T2D. However, a prospective clinical trial is warranted.

Emerging Role of mTOR Signaling-Related miRNAs in Cardiovascular Diseases

Mechanistic/mammalian target of rapamycin (mTOR), an atypical serine/threonine kinase of the phosphoinositide 3-kinase- (PI3K-) related kinase family, elicits a vital role in diverse cellular processes, including cellular growth, proliferation, survival, protein synthesis, autophagy, and metabolism. In the cardiovascular system, the mTOR signaling pathway integrates both intracellular and extracellular signals and serves as a central regulator of both physiological and pathological processes. MicroRNAs (miRs), a class of short noncoding RNA, are an emerging intricate posttranscriptional modulator of critical gene expression for the development and maintenance of homeostasis across a wide array of tissues, including the cardiovascular system. Over the last decade, numerous studies have revealed an interplay between miRNAs and the mTOR signaling circuit in the different cardiovascular pathophysiology, like myocardial infarction, hypertrophy, fibrosis, heart failure, arrhythmia, inflammation, and atherosclerosis. In this review, we provide a comprehensive state of the current knowledge regarding the mechanisms of interactions between the mTOR signaling pathway and miRs. We have also highlighted the latest advances on mTOR-targeted therapy in clinical trials and the new perspective therapeutic strategies with mTOR-targeting miRs in cardiovascular diseases.