LncRNA SOX2OT alleviates the high glucose-induced podocytes injury through autophagy induction by the miR-9/SIRT1 axis

LncRNA SNHG14 silencing attenuates the progression of diabetic nephropathy via the miR-30e-5p/SOX4 axis

BACKGROUND

Diabetic nephropathy (DN) is a diabetic complication. LncRNAs are reported to participate in the pathophysiology of DN. Here, the function and mechanism of lncRNA small nucleolar RNA host gene 14 (SNHG14) in DN were explored.

METHODS

Streptozotocin (STZ)-induced DN mouse models and high glucose (HG)-treated human mesangial cells (MCs) were used to detect SNHG14 expression. SNHG14 silencing plasmids were applied to examine the function of SNHG14 on proliferation and fibrosis in HG-treated MCs. Potential targets of SNHG14 were predicted using bioinformatics tools and verified by luciferase reporter, RNA pulldown, and northern blotting assays. The functional role of SNHG14 in DN in vivo was detected by injection with adenoviral vector carrying sh-SNHG14 into DN mice. Serum creatinine, blood urea nitrogen, blood glucose, 24-h proteinuria, relative kidney weight, and renal pathological changes were examined in DN mice.

RESULTS

SNHG14 expression was elevated in the kidneys of DN mice and HG-treated MCs. SNHG14 silencing inhibited proliferation and fibrosis of HG-stimulated MCs. SNHG14 bound to miR-30e-5p to upregulate SOX4 expression. In rescue assays, SOX4 elevation diminished the effects of SNHG14 silencing in HG-treated MCs, and SOX4 silencing reversed the effects of SNHG14 overexpression. In in vivo studies, SNHG14 downregulation significantly ameliorated renal injuries and renal interstitial fibrosis in DN mice.

CONCLUSIONS

SNHG14 silencing attenuates kidney injury in DN mice and reduces proliferation and fibrotic phenotype of HG-stimulated MCs via the miR-30e-5p/SOX4 axis.

The regulatory role of miRNA and lncRNA on autophagy in diabetic nephropathy

Diabetic nephropathy (DN) is a serious complication of diabetes that causes glomerular sclerosis and end-stage renal disease, leading to ascending morbidity and mortality in diabetic patients. Excessive accumulation of aberrantly modified proteins or damaged organelles, such as advanced glycation end-products, dysfunctional mitochondria, and inflammasomes is associated with the pathogenesis of DN. As one of the main degradation pathways, autophagy recycles toxic substances to maintain cellular homeostasis and autophagy dysregulation plays a crucial role in DN progression. MicroRNA (miRNA) and long non-coding RNA (lncRNA) are non-coding RNA (ncRNA) molecules that regulate gene expression and have been implicated in both physiological and pathological conditions. Recent studies have revealed that autophagy-regulating miRNA and lncRNA have been involved in pathological processes of DN, including renal cell injury, mitochondrial dysfunction, inflammation, and renal fibrosis. This review summarizes the role of autophagy in DN and emphasizes the modulation of miRNA and lncRNA on autophagy during disease progression, for the development of promising interventions by targeting these ncRNAs in this disease.

Long non-coding RNAs as emerging regulators of miRNAs and epigenetics in diabetes-related chronic kidney disease

Diabetes is one of the major cause of chronic kidney disease (CKD), including "diabetic nephropathy," and is an increasingly prevalent accelerator of the progression of non-diabetic forms of CKD. The long non-coding RNAs (lncRNAs) have come into the limelight in the past few years as one of the emerging weapons against CKD in diabetes. Available data over the past few years demonstrate the interaction of lncRNAs with miRNAs and epigenetic machinery. Interestingly, the evolving data suggest that lncRNAs play a vital role in diabetes-associated CKD by regulation of epigenetic enzymes such as DNA methyltransferase, histone deacetylases, and histone methyltransferases. LncRNAs are also engaged in the regulation of several miRNAs in diabetic nephropathy. Hence this review will elaborate on the association between lncRNAs and their interaction with epigenetic regulators involved in different aspects and thus the progression of CKD in diabetes.

Cadmium exposure caused cardiotoxicity in common carps (Cyprinus carpio L.): miR-9-5p, oxidative stress, energetic impairment, mitochondrial division/fusion imbalance, inflammation, and autophagy

Cadmium (Cd), a toxic heavy metal pollutant, is a threat to human and eatable fish health. Common carps are widely cultivated and eaten by humans. However, there are no reports about Cd-damaged common carp hearts. Our experiment attempted to investigate the cardiotoxicity of Cd to common carps by establishing a common carp Cd exposure model. Our results showed that Cd injured hearts. Moreover, Cd treatment induced autophagy via miR-9-5p/Sirt1/mTOR/ULK1 pathway. Cd exposure caused oxidant/antioxidant imbalance and oxidative stress; and led to energetic impairment. Energetic impairment partook in oxidative stress-mediated autophagy through AMPK/mTOR/ULK1 pathway. Furthermore, Cd caused mitochondrial division/fusion imbalance and resulted in inflammatory injury via NF-κB-COX-2-PTGEs and NF-κB-COX-2-TNF-α pathways. Oxidative stress mediated mitochondrial division/fusion imbalance, further induced inflammation and autophagy via OPA1/NF-κB-COX-2-TNF-α-Beclin1 and OPA1/NF-κB-COX-2-TNF-α/P62 pathways under Cd treatment. Taken together, miR-9-5p, oxidative stress, energetic impairment, mitochondrial division/fusion imbalance, inflammation, and autophagy participated in the mechanism of Cd-cardiotoxicity to common carps. Our study revealed harmful effect of Cd on hearts, and provided new information for researches of environmental pollutant toxicity.

Forkhead box A2-mediated lncRNA SOX2OT up-regulation alleviates oxidative stress and apoptosis of renal tubular epithelial cells by promoting SIRT1 expression in diabetic nephropathy

BACKGROUND

Renal tubular injury is the main feature of diabetic nephropathy (DN). We intend to investigate the function and related mechanisms of lncRNA SOX2 overlapping transcript (SOX2OT) in high glucose (HG)-induced oxidative stress and apoptosis of renal tubular epithelial cells (RTECs).

METHODS

To construct diabetes models, the human kidney-2 (HK-2) cells were treated with HG (30 mM), and mice were injected with streptozotocin. The levels of intracellular and mitochondrial reactive oxygen species (ROS) were assessed by dihydroethidium staining and MitoSox staining. The cell apoptosis was assessed by flow cytometry and TUNEL staining. Levels of serum creatinine, blood urea nitrogen (BUN), Urinary ACR, and oxidative stress marker 8-hydroxy-2'-deoxyguanosine (8-OHdG) were detected by relevant kits. In addition, fluorescence in situ hybridization staining, RNA-pull down, RNA immunoprecipitation (RIP), co-immunoprecipitation (co-IP), dual-luciferase reporter gene assay and chromatin immunoprecipitation (ChIP) were also executed.

RESULTS

Levels of SOX2OT and silent information regulator 1 (SIRT1) were down-regulated in HG-cultured HK-2 cells. Overexpressing SOX2OT reduced intracellular and mitochondrial ROS levels and cell apoptosis in vitro. Moreover, SOX2OT overexpression also reduced serum creatinine, BUN, urinary ACR, 8-OHdG, renal tubular injury markers KIM1 and NGAL, ROS levels, and cell apoptosis in vivo. In addition, SOX2OT promoted SIRT1 expression by suppressing its ubiquitination. Besides, interference with SIRT1 reversed the inhibitory effect of SOX2OT overexpression on HG-induced oxidative stress and apoptosis. Forkhead box A2 (Foxa2) levels were up-regulated in HG-cultured HK-2 cells. Foxa2 could bind to the SOX2OT promoter and suppress its expression. Furthermore, interfering with SOX2OT reversed the inhibitory effect of Foxa2 interference on HG-induced oxidative stress and apoptosis.

CONCLUSION

Foxa2-mediated SOX2OT up-regulation reduced oxidative stress and apoptosis of RTECs by promoting SIRT1 expression, thus alleviating the progression of DN.

Sirtuins as novel pharmacological targets in podocyte injury and related glomerular diseases

Podocyte injury is a major cause of proteinuria in kidney diseases, and persistent loss of podocytes leads to rapid irreversible progression of kidney disease. Sirtuins, a class of nicotinamide adenine dinucleotide-dependent deacetylases, can promote DNA repair, modify transcription factors, and regulate the cell cycle. Additionally, sirtuins play a critical role in renoprotection, particularly against podocyte injury. They also have pleiotropic protective effects on podocyte injury-related glomerular diseases, such as improving the immune inflammatory status and oxidative stress levels, maintaining mitochondrial homeostasis, enhancing autophagy, and regulating lipid metabolism. Sirtuins deficiency causes podocyte injury in different glomerular diseases. Studies using podocyte sirtuin-specific knockout and transgenic models corroborate this conclusion. Of note, sirtuin activators have protective effects in different podocyte injury-related glomerular diseases, including diabetic kidney disease, focal segmental glomerulosclerosis, membranous nephropathy, IgA nephropathy, and lupus nephritis. These findings suggest that sirtuins are promising therapeutic targets for preventing podocyte injury. This review provides an overview of recent advances in the role of sirtuins in kidney diseases, especially their role in podocyte injury, and summarizes the possible rationale for sirtuins as targets for pharmacological intervention in podocyte injury-related glomerular diseases.

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.

Long Non-Coding RNAs in the Pathogenesis of Diabetic Kidney Disease

Diabetic kidney disease (DKD) is one of the major microvascular complications of diabetes mellitus, with relatively high morbidity and mortality globally but still in short therapeutic options. Over the decades, a large body of data has demonstrated that oxidative stress, inflammatory responses, and hemodynamic disorders might exert critical influence in the initiation and development of DKD, whereas the delicate pathogenesis of DKD remains profoundly elusive. Recently, long non-coding RNAs (lncRNAs), extensively studied in the field of cancer, are attracting increasing attentions on the development of diabetes mellitus and its complications including DKD, diabetic retinopathy, and diabetic cardiomyopathy. In this review, we chiefly focused on abnormal expression and function of lncRNAs in major resident cells (mesangial cell, endothelial cell, podocyte, and tubular epithelial cell) in the kidney, summarized the critical roles of lncRNAs in the pathogenesis of DKD, and elaborated their potential therapeutic significance, in order to advance our knowledge in this field, which might help in future research and clinical treatment for the disease.

Long non‑coding RNA TUG1 sponges microRNA‑9 to protect podocytes from high glucose‑induced apoptosis and mitochondrial dysfunction via SIRT1 upregulation

Podocyte apoptosis and mitochondrial dysfunction serve a major role in diabetic nephropathy progression. The present study revealed a molecular mechanism regulating podocyte apoptosis and mitochondrial dysfunction. In vitro models were established using conditionally immortalized mouse podocyte clonal cells treated with high glucose (HG). Reverse quantitative-transcription PCR were used to detect gene expression, western blotting and immunofluorescence were used to detect protein expression, Cell Counting Kit-8 was used to detect cell viability and flow cytometry was used to detect cell apoptosis. HG treatment in the mouse podocyte clonal cells downregulated taurine-upregulated gene 1 (TUG1) expression and decreased viability in a dose-dependent manner. In addition, TUG1 knockdown (KD) increased HG-induced apoptosis, while TUG1 overexpression (OE) reduced HG-induced apoptosis in podocytes. HG-induced mitochondrial dysfunction was identified in podocytes, with increased reactive oxygen species levels, decreased complex I/III activity and decreased basal/maximal oxygen consumption rate. TUG1 KD worsened HG-induced mitochondrial dysfunction, and TUG1 OE reversed these effects. At the molecular level, TUG1 was revealed to promote sirtuin 1 (SIRT1) expression by sponging microRNA (miR)-9, and SIRT1 OE reversed the HG-induced apoptosis and mitochondrial dysfunction increased by TUG1 KD. The present data indicated that downregulation of TUG1 induced by HG was associated with HG-induced apoptosis and mitochondrial dysfunction in podocytes, and that TUG1 protected HG-induced podocytes by promoting SIRT1 expression via miR-9 inhibition.

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

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

CDKN2B-AS1 participates in high glucose-induced apoptosis and fibrosis via NOTCH2 through functioning as a miR-98-5p decoy in human podocytes and renal tubular cells

BACKGROUND

Diabetic nephropathy (DN) is the most common causes of end-stage renal disease. Long non-coding RNA cyclin-dependent kinase inhibitor 2B antisense RNA 1 (CDKN2B-AS1) is connected with the development of DN, but the role of CDKN2B-AS1 in DN has not been entirely elucidated.

METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR) was carried out to measure CDKN2B-AS1 and miR-98-5p levels. Cell viability, proliferation, and apoptosis were analyzed with 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) or flow cytometry assays. Protein levels were measured by western blotting. The relationship between CDKN2B-AS1 or notch homolog 2 (NOTCH2) and miR-98-5p was verified via dual-luciferase reporter assay.

RESULTS

CDKN2B-AS1 and NOTCH2 were upregulated in the serum of DN patients and high glucose-disposed human podocytes (HPCs) and human renal tubular cells (HK-2), whereas miR-98-5p was downregulated. High glucose repressed viability and accelerated apoptosis of HPCs and HK-2 cells. CDKN2B-AS1 knockdown impaired high glucose-induced apoptosis and fibrosis of HPCs and HK-2 cells. Mechanistically, CDKN2B-AS1 sponged miR-98-5p to regulate NOTCH2 expression. Also, CDKN2B-AS1 inhibition-mediated effects on apoptosis and fibrosis of high glucose-disposed HPCs and HK-2 cells were weakened by miR-98-5p inhibitor. Also, NOTCH2 knockdown partly reversed miR-98-5p inhibitor-mediated impacts on apoptosis and fibrosis of high glucose-disposed HPCs and HK-2 cells.

CONCLUSION

High glucose-induced CDKN2B-AS1 promoted apoptosis and fibrosis via the TGF-β1 signaling mediated by the miR-98-5p/NOTCH2 axis in HPCs and HK-2 cells.

Long non-cording RNA XIST promoted cell proliferation and suppressed apoptosis by miR-423-5p/HMGA2 axis in diabetic nephropathy

This research studied the effect of long non-coding RNA X-inactive-specific transcript (XIST) on DN. The effect of high glucose (HG) on the expression of XIST and miR-423-5p was detected by quantitative real-time PCR (qRT-PCR) in human kidney (HK) cells (human glomerular mesangial cells (HMCs) and human kidney-2 (HK-2) cells). The effect of XIST depletion and miR-423-5p inhibition or overexpression on high mobility group protein A2 (HMGA2) protein level was examined by western blot in HG-induced HK cells. The impacts of XIST depletion on viability and apoptosis were assessed by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) and flow cytometry assays in HG-induced HK cells. We found the expression of XIST and HMGA2 protein was significantly upregulated in DN tissues and cells. Moreover, HG treatment induced the upregulation of XIST and HMGA2 protein level in HK cells. Besides, both XIST depletion and HMGA2 depletion decreased cell proliferation but increased apoptosis in HG-treated HK cells. Furthermore, HMGA2 upregulation or miR-423-5p inhibition partly eliminated the effects of XIST depletion on cell proliferation, apoptosis of HG-treated HK cells. Interestingly, HMGA2 upregulation partly reversed miR-423-5p overexpression-mediated suppression on viability and promotion on apoptosis in HG-treated HK cells. Mechanistically, XIST sponged miR-423-5p to regulate HMGA2 expression in DN cells. Taken together, XIST depletion suppressed proliferation and promoted apoptosis via miR-423-5p/HMGA2 axis in HG-treated HK cells, which may provide a potential therapeutic target for DN.

LncRNA SOX2OT alleviates mesangial cell proliferation and fibrosis in diabetic nephropathy via Akt/mTOR-mediated autophagy

Background

Accumulating evidences have demonstrated that long non-coding RNAs (lncRNAs) are involved in the pathophysiology of diabetic nephropathy (DN). lncRNA SOX2OT plays an essential role in many diseases, including diabetes. Herein, we aim to investigate the underlying mechanism of lncRNA SOX2OT in DN pathogenesis.

Methods

Streptozotocin-induced DN mouse models and high glucose-induced mouse mesangial cells were constructed to examine the expression pattern of lncRNA SOX2OT. The activation of autophagy was evaluated using immunohistochemistry, immunofluorescence and western blot analysis, respectively. SOX2OT overexpressing plasmid was applied to further verify the functional role of SOX2OT in DN pathogenesis. CCK-8 and EDU assays were performed to the proliferation of mesangial cells. Additionally, rapamycin, the inhibitor of mTOR signaling, was used to further clarify whether SOX2OT controls DN development through Akt/mTOR pathway.

Results

lncRNA SOX2OT was markedly down-regulated both in streptozotocin-induced DN mice and high glucose-induced mouse mesangial cells. Moreover, overexpression of lncRNA SOX2OT was able to diminish the suppression of autophagy and alleviate DN-induced renal injury. Functionally, CCK-8 and EDU assays indicated that lncRNA SOX2OT overexpression significantly suppressed the proliferation and fibrosis of mesangial cells. Additionally, an obvious inhibition of Akt/mTOR was also observed with lncRNA SOX2OT overexpression, which was then further verified in vivo.

Conclusion

In summary, we demonstrated that lncRNA SOX2OT alleviates the pathogenesis of DN via regulating Akt/mTOR-mediated autophagy, which may provide a novel target for DN therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-021-00310-6.

Knockdown of FAM225B inhibits the progression of the hypertrophic scar following glaucoma surgery by inhibiting autophagy

The formation of a hypertrophic scar (HS) may lead to failure of glaucoma surgery. Long non-coding RNAs (lncRNAs) are involved in the formation of HSs. Moreover, family with sequence similarity 225 member B (FAM225B) is upregulated in HS. However, the role of the lncRNA FAM225B in HS remains unknown. Thus, the present study aimed to investigate the function of FAM225B in HS. Scar fibroblasts were isolated from patients who had undergone glaucoma surgery. Western blotting was used to detect the expressions of Bax, Bcl-2, cleaved caspase 3, p62, ATG7 and Beclin 1, and reverse transcription-quantitative PCR (RT-qPCR) were conducted to determine the level of FAM225B in scar fibroblasts. Microtubule associated protein 1 light chain 3 α staining was performed to examine autophagosomes in scar fibroblasts. Furthermore, cell proliferation was evaluated via 5-ethynyl-2′-deoxyuridine staining. Flow cytometry was conducted to determine cell apoptosis and the levels of reactive oxygen species (ROS) in scar fibroblasts. The cell migratory ability was assessed using a Transwell assay. The results demonstrated that FAM225B knockdown significantly attenuated scar fibroblast proliferation and induced apoptosis. Additionally, transfection of scar fibroblasts with FAM225B small interfering RNA (siRNA) significantly increased the ROS levels and significantly decreased the migration of scar fibroblasts. The FAM225B overexpression-induced increase of scar fibroblast proliferation and migration was significantly reversed by 3-methyladenine administration. The results suggested that knockdown of FAM225B significantly inhibited the proliferation of scar fibroblasts by inhibiting autophagy. Therefore, knockdown of FAM225B could inhibit scar fibroblast proliferation after glaucoma surgery by inhibiting autophagy. These findings may provide a novel perspective of developing treatment strategy for the patients with HSs after glaucoma surgery.

LncRNA SOX2OT is Upregulated in Gestational Diabetes Mellitus (GDM) and Correlated with Multiple Adverse Events

PURPOSE

LncRNA SOX2OT plays protective roles in high glucose-induced injuries, suggesting its potential involvement in diabetes. Therefore, we analyzed the role of SOX2OT in gestational diabetes mellitus (GDM).

METHODS

A total of 216 pregnant women with a gestational age of about 2 months were enrolled in this study. The 216 pregnant women were monitored until delivery to record the occurrence of GDM. Adverse events, including miscarriage, premature delivery, intrauterine distress, intrauterine death, intrauterine infection, fetal malformation, macrosomia, and hypertension, were recorded.

RESULTS

Two hundred sixteen pregnant women were divided into high and low SOX2OT level groups (n=108), with the median plasma SOX2OT level on the day of admission as the cutoff value. It was observed that the incidence of GDM was higher in the high SOX2OT level group (40/108) than in the low SOX2OT level group (12/108). Moreover, the SOX2OT expression level was higher in GDM patients than in non-GDM participants, and ROC curve analysis showed that plasma SOX2OT levels on the day of admission could separate potential GDM patients from the rest participants. Importantly, higher incidences of miscarriage, premature delivery, intrauterine distress, intrauterine death, intrauterine infection, fetal malformation, macrosomia, and hypertension were observed in the high SOX2OT group compared to the low SOX2OT group.

CONCLUSION

SOX2OT is highly expressed in GDM and is closely correlated with multiple adverse events.

MiR-203-3p inhibits the oxidative stress, inflammatory responses and apoptosis of mice podocytes induced by high glucose through regulating Sema3A expression

Diabetic nephropathy (DN) is the most serious long-term microvascular complication of diabetes, which mainly causes podocyte injury. Many studies have shown that microRNAs play a vital role in the development of DN. Studies have shown that miR-203-3p is involved in mesangial cell proliferation and apoptosis of DN mice. Therefore, we speculated that miR-203-3p might be related to the development of DN, but our study does not provide any evidence. In animal experiments, diabetic mice (db/db) were transfected with iR-203-3p overexpression lentiviral vectors (LV-miR-203-3p) and their control (LV-miR-con), with normal mice (db/m) being used as the control. High glucose (HG)-induced podocytes were used to construct a DN cell model in vitro. The expression levels of miR-203-3p, Semaphorin 3A (Sema3A) and inflammatory cytokines were detected by quantitative real-time polymerase chain reaction. Also, serum creatinine and blood urea nitrogen levels were used to evaluate the degree of renal injury in DN mice. Sema3A and apoptosis-related protein levels were assessed by the western blot analysis. Enzyme-linked immunosorbent assay was used to determine the different oxidative stress-related indicators and inflammatory cytokines. Flow cytometry and caspase-3 activity detection were used to analyze the degree of podocyte apoptosis. Our results suggested that the expression of miR-203-3p was lower in DN mice and in HG-induced podocytes. Overexpression of miR-203-3p reduced the body weight, blood glucose and renal injury of DN mice in vivo, as well as relieve the oxidative stress, inflammatory response and apoptosis of HG-induced podocytes in vitro. Functionally, Sema3A was a target of miR-203-3p, and Sema3A overexpression reversed the inhibitory effect of miR-203-3p on HG-induced podocyte injury. Our findings revealed that miR-203-3p alleviated the podocyte injury induced by HG via regulating Sema3A expression, suggesting that miR-203-3p might be a new therapeutic target to improve the progression of DN.

Long Noncoding RNA SOX2-OT: Regulations, Functions, and Roles on Mental Illnesses, Cancers, and Diabetic Complications

SRY-box transcription factor 2 (SOX2) overlapping transcript (SOX2-OT) is an evolutionarily conserved long noncoding RNA. Its intronic region contains the SOX2 gene, the major regulator of the pluripotency of embryonic stem cells. The human SOX2-OT gene comprises multiple exons and has multiple transcription start sites and generates hundreds of transcripts. Transcription factors (IRF4, AR, and SOX3), transcriptional inhibitors (NSPc1, MTA3, and YY1), and miRNAs (miR-211 and miR-375) have been demonstrated to control certain SOX2-OT transcript level at the transcriptional or posttranscriptional levels. Accumulated evidence indicates its crucial roles in the regulation of the SOX2 gene, miRNAs, and transcriptional process. Restricted expression of SOX2-OT transcripts in the brain results in the association between SOX2-OT single nucleotide polymorphisms and mental illnesses such as schizophrenia and anorexia nervosa. SOX2-OT is notably elevated in tumor tissues, and a high level of SOX2-OT is well correlated with poor clinical outcomes in cancer patients, leading to the establishment of its role as an oncogene and a prognostic or diagnostic biomarker for cancers. The emerging evidence supports that SOX2-OT mediates diabetic complications. In summary, SOX2-OT has diversified functions and could be a therapeutic target for various diseases.

LncRNA SOX2OT/Smad3 feedback loop promotes myocardial fibrosis in heart failure

Long noncoding RNA SOX2OT is associated with myocardial fibrosis (MF) in heart failure (HF). This article aims to investigate the role of SOX2OT in MF. We constructed HF mouse models by subcutaneous injection of isoprenaline (ISO). Cardiac fibroblasts (CFs) were treated with ISO to induce MF.Hematoxylin-eosin, Masson, and Sirius-red staining were used to identify myocardial injury and collagen deposition in heart tissues. The relationship among SOX2OT, miR-138-5p, TGF-β1, and Smad3 were evaluated by chromatin immunoprecipitation and luciferase reporter assay. The gene and protein expression were verified by quantitative real-time PCR and western blot. We found that SOX2OT was up-regulated in HF mice and ISO-induced CFs. SOX2OT knockdown reduced myocardial injury and collagen deposition in HF mice. The expression of collagen I, α-SMA, TGF-β1, and p-Smad3 were inhibited by SOX2OT down-regulation in HF mice and ISO-induced CFs. Furthermore, TGF-β1 was a target gene of miR-138-5p and indirectly regulated by SOX2OT. SOX2OT promoted MF in HF by activating TGF-β1/Smad3, and then Smad3 interacted with the SOX2OT promoter and formed a positive feedback loop. In conclusion, our work verifies that SOX2OT/Smad3 feedback loop promotes MF in HF. Thus, SOX2OT is potentially a novel therapeutic target for MF in HF.

LncRNA SNHG16 induces proliferation and fibrogenesis via modulating miR-141-3p and CCND1 in diabetic nephropathy

LncRNAs are reported to participate in the progression of various diseases including diabetic nephropathy. Currently, we reported that SNHG16 was obviously upregulated in db/db mice and high glucose-treated mice mesangial cells. Then, functional experiments showed that SNHG16 silencing significantly inhibited proliferation of mice mesangial cells, which induced the apoptosis and triggered cell cycle arrest. Meanwhile, proliferation-related biomarkers PCNA and Cyclin D1 (CCND1) were greatly repressed. Furthermore, western blot analysis was conducted to test fibrogenesis-associated genes Fibronectin and α-SMA. Meanwhile, the increased protein expression levels of Fibronectin and α-SMA under high glucose conditions were reversed by loss of SNHG16. miR-141-3p has been reported to be involved in various diseases. Then, RNA immunoprecipitation assay revealed the relation between SNHG16 and miR-141-3p. Downregulation of SNHG16 was able to induce expression of miR-141-3p, which was obviously reduced in db/db diabetic nephropathy mice. In addition, CCND1 is a crucial cell cycle master in human diseases. CCND1 was speculated as the target of miR-141-3p and miR-141-3p inhibited CCND1 expression significantly. Meanwhile, we observed that loss of CCND1 greatly repressed mice mesangial cell proliferation and induced cell apoptosis. Taken these together, we revealed for the first time that SNHG16 induced proliferation and fibrogenesis via modulating miR-141-3p and CCND1 in diabetic nephropathy. SNHG16/miR-141-3p/CCND1 axis can suggest a pathological mechanism of progression of diabetic nephropathy.

Long non-coding RNA cancer susceptibility candidate 2 (CASC2) alleviates the high glucose-induced injury of CIHP-1 cells via regulating miR-9-5p/PPARγ axis in diabetes nephropathy

BACKGROUND

High glucose (HG) induced podocytes injury plays an important role in diabetes nephropathy (DN) development. Long noncoding RNA cancer susceptibility candidate 2 (CASC2) was found to be decreased in serum of DN patients. We aimed to explore the function and possible mechanism of CASC2 in HG induced podocytes injury.

METHODS

Under normal glucose (NG), HG and mannitol stimulated podocyte conditions, the levels of CASC2, microRNA-9-5p (miR-9-5p) and peroxisome proliferator-activated receptor gamma (PPARγ) were examined by quantitative real-time polymerase chain reaction (qRT-PCR). Podocyte injury was evaluated by measuring cell viability and apoptosis of CIHP-1 cells were checked by cell counting kit-8 (CCK-8) assay and flow cytometry, respectively. Western blot was used to detect all protein levels. Dual-luciferase reporter, RNA immunoprecipitation (RIP) and RNA pull-down assays were performed to confirm the relationship between CASC2 and miR-9-5p.

RESULTS

HG stimulation inhibited the expression levels of CASC2 and PPARγ, but promoted the expression of miR-9-5p. HG could restrain cell viability, autophagy and facilitate apoptosis in CIHP-1 cells, while CASC2 overexpression could reverse HG-induced podocytes injury. Furthermore, CASC2 could be used as a ceRNA to adsorb miR-9-5p, and miR-9-5p mimic overturned the effects of CASC2 on cell viability, autophagy and apoptosis in HG-stimulated podocytes. Additionally, PPARγ was a target gene of miR-9-5p, and CASC2 could weaken the HG-induced podocytes injury by up-regulating PPARγ.

CONCLUSION

CASC2 increased cell viability, autophagy and inhibited cell apoptosis by regulating miR-9-5p/PPARγ axis, thus reducing the HG-induced podocytes injury.

Epigenetic Regulation Associated With Sirtuin 1 in Complications of Diabetes Mellitus

Diabetes mellitus (DM) has been one of the largest health concerns of the 21st century due to the serious complications associated with the disease. Therefore, it is essential to investigate the pathogenesis of DM and develop novel strategies to reduce the burden of diabetic complications. Sirtuin 1 (SIRT1), a nicotinamide adenosine dinucleotide (NAD⁺)-dependent deacetylase, has been reported to not only deacetylate histones to modulate chromatin function but also deacetylate numerous transcription factors to regulate the expression of target genes, both positively and negatively. SIRT1 also plays a crucial role in regulating histone and DNA methylation through the recruitment of other nuclear enzymes to the chromatin. Furthermore, SIRT1 has been verified as a direct target of many microRNAs (miRNAs). Recently, numerous studies have explored the key roles of SIRT1 and other related epigenetic mechanisms in diabetic complications. Thus, this review aims to present a summary of the rapidly growing field of epigenetic regulatory mechanisms, as well as the epigenetic influence of SIRT1 on the development and progression of diabetic complications, including cardiomyopathy, nephropathy, and retinopathy.

Noncoding RNAs in Diabetic Nephropathy: Pathogenesis, Biomarkers, and Therapy

The correlation between diabetes and systematic well-being on human life has long established. As a common complication of diabetes, the prevalence of diabetic nephropathy (DN) has been increasing globally. DN is known to be a major cause of end-stage kidney disease (ESKD). Till now, the molecular mechanisms for DN have not been fully explored and the effective therapies are still lacking. Noncoding RNAs are a class of RNAs produced by genome transcription that cannot be translated into proteins. It has been documented that ncRNAs participate in the pathogenesis of DN by regulating inflammation, apoptosis, autophagy, cell proliferation, and other pathological processes. In this review, the pathological roles and diagnostic and therapeutic potential of three types of ncRNAs (microRNA, long noncoding RNA, and circular RNA) in the progression of DN are summarized and illustrated.