Long noncoding RNA-GAS5 retards renal fibrosis through repressing miR-21 activity

Oridonin Attenuates Diabetes‑induced Renal Fibrosis via the Inhibition of TXNIP/NLRP3 and NF‑κB Pathways by Activating PPARγ in Rats

INTRODUCTION

Oridonin possesses remarkable anti-inflammatory, immunoregulatory properties. However, the renoprotective effects of oridonin and the underlying molecular mechanisms in diabetic nephropathy (DN). We hypothesized that oridonin could ameliorate diabetes‑induced renal fibrosis.

METHODS

Streptozocin (STZ)-induced diabetic rats were provided with a high-fat diet to establish a type 2 diabetes mellitus (T2DM) animal model, and then treated with Oridonin (10, 20 mg/kg/day) for two weeks. Kidney function and renal fibrosis were assessed. High glucose-induced human renal proximal tubule epithelial cells (HK-2) were also treated with oridonin. The expression of inflammatory factors and fibrotic markers were analyzed.

RESULTS

Oridonin treatment preserved kidney function and markedly limited the renal fibrosis size in diabetic rats. The renal fibrotic markers were inhibited in the oridonin 10 mg/kg/day and 20 mg/kg/day groups compared to the T2DM group. The expression of thioredoxin-interacting proteins/ nod-like receptor protein-3 (TXNIP/NLRP3) and nuclear factor (NF)‑κB pathway decreased, while that of peroxisome proliferator-activated receptor-gamma (PPARγ) increased in the oridonin treatment group compared to the non-treated group. In vitro, PPARγ intervention could significantly regulate the effect of oridonin on the high glucose-induced inflammatory changes in HK-2 cells.

CONCLUSION

Oridonin reduces renal fibrosis and preserves kidney function via the inhibition of TXNIP/NLRP3 and NF‑κB pathways by activating PPARγ in rat T2DM model, which indicates potential effect of oridonin in the treatment of DN.

LncR-GAS5 decrease in adenine phosphoribosyltransferase expresssion via binding TAF1 to increase kidney damage created by CIH

Objective

Chronic kidney disease (CKD) related to obstructive sleep apnea-hypopnea syndrome (OSAHS) mainly results from chronic intermittent hypoxia (CIH)-induced renal injury. This study aimed to explore the interaction between the long noncoding RNA (lncRNA) growth arrest-specific transcript 5 (GAS5) and recombinant adenine phosphoribosyltransferase (APRT) in CIH-induced renal injury.

Methods

A rat intermittent hypoxia model was constructed, total RNA was extracted from kidney tissue, and transcriptome sequencing was performed using high-throughput sequencing technology. CIH rat models were established and injected with sh-GAS5 or OE-APRT plasmid, the serum levels of blood urea nitrogen (BUN) and creatinine amidohydrolase were measured, and the expression of oxidative stress-related factors was detected. Hematoxylin and eosin (H&E) and Masson's trichrome staining were used for morphological observations, and cell apoptosis was determined by TUNEL staining. Interactions between GAS5, TATA-box binding protein-associated factor 1 (TAF1), and APRT were predicted and verified. After transfection of HK-2 cells, the expression of GAS5, TAF1, APRT, Bax, Bcl-2, apoptosis-related factors, fibrosis-related factors (collagen I and Ⅳ), and autophagy-related proteins (LC3-Ⅱ, LC3-Ⅰ, p62, and Beclin-1) was measured by RT-qPCR and western blotting.

Results

Sequencing results revealed that TAF1 was significantly increased and APRT was significantly decreased in the CIH group. RNA was significantly involved in the biological process of kidney injury mediated by CIH. CIH rats injected with GAS5 suppression or APRT overexpression plasmids showed decreased GAS5 and elevated APRT expression, along with suppressed serum levels of BUN and creatinine amidohydrolase. Meanwhile, GAS5 suppression or APRT overexpression attenuated apoptosis and fibrosis, suppressed oxidative stress, and promoted autophagy in CIH-induced renal tubular epithelial cells. The RNA pull-down assay and RIP verified the binding and interaction of GAS5 and TAF1. Chip immunoprecipitation (ChIP) identified TAF1 regulation of the APRT promoter. GAS5 and TAF1 negatively regulated APRT expression.

Conclusion

The lncRNA GAS5 can bind TAF1 to suppress APRT transcription, thereby enhancing CIH-induced renal injury in rats.

The m6A demethylase FTO promotes renal epithelial-mesenchymal transition by reducing the m6A modification of lncRNA GAS5

BACKGROUND

Renal interstitial fibrosis (RIF) is the main pathological change of a variety of chronic kidney diseases (CKD). Epigenetic modifications of fibrosis-prone genes regulate RIF progression. This study aimed to investigate long non-coding RNA (lncRNA) N6-methyladenosine (m⁶A) modification and its role in regulating RIF progression.

METHODS

Unilateral ureteral occlusion (UUO) was employed to construct the RIF in vivo model; and TGF-β1-treated HK-2 and HKC-8 cells were used for in vitro experiments. The mRNA and protein expressions were assessed using qRT-PCR and western blot. The proliferation and migration were evaluated by EdU assay and transwell assay, respectively. In addition, levels of inflammatory cytokines were determined by ELISA assay and qRT-PCR. Moreover, lncRNA GAS5 m⁶A level was detected using Me-RIP assay. HE and Masson staining were employed to evaluate fibrotic lesions of the kidney.

RESULTS

FTO expression was elevated in HK-2 and HKC-8 cells after TGF-β1 treatment and mouse kidney tissue following UUO, and lncRNA GAS5 was downregulated. LncRNA GAS5 overexpression or FTO silencing suppressed TGF-β1-induced the increase of EMT-related proteins (Vimentin, Snail and N-cadherin) and inflammatory cytokines (IL-6, IL-1β and TNF-α) levels in HK-2 cells. FTO suppressed lncRNA GAS5 expression by reducing the m6A modification of lncRNA GAS5. Additionally, FTO knockdown could suppress EMT process and inflammation response induced by TGF-β1 and UUO in vitro and in vivo. As expected, FTO knockdown abrogated the promotion effects of lncRNA GAS5 silencing on TGF-β1-induced EMT process and inflammation response in HK-2 and HKC-8 cells.

CONCLUSION

FTO promoted EMT process and inflammation response through reducing the m⁶A modification of lncRNA GAS5.

MIP From Legionella pneumophila Influences the Phagocytosis and Chemotaxis of RAW264.7 Macrophages by Regulating the lncRNA GAS5/miR-21/SOCS6 Axis

Background

The intracellular pathogen Legionella pneumophila (L. pneumophila) is a causative agent of pneumonia and does great harm to human health. These bacteria are phagocytosed by alveolar macrophages and survive to replicate within the macrophages. Despite macrophage infectivity potentiator (MIP) protein serving as an essential virulence factor during the invasion process of L. pneumophila, the regulatory mechanism of MIP protein in the process of bacterial infection to host cells is not yet completely understood. This research thus aims to explore the interaction between MIP and macrophage phagocytosis.

Methods

Through the experiment of the co-culture of RAW264.7 macrophages with different concentrations of MIP, the chemotactic activity of macrophages was detected and the phagocytosis was determined by a neutral red uptake assay. The expression of long noncoding RNA (lncRNA) GAS5, microRNA-21 (miR-21), and suppressor of cytokine signaling (SOCS)6 was determined by qRT-PCR. Target genes were detected by dual luciferase assay.

Results

MIP could reduce the phagocytosis and improve the chemotaxis of RAW264.7 macrophages. The expression of both lncRNA GAS5 and SOCS6 was increased whereas the expression of miR-21 was decreased when macrophages were treated with MIP. Dual luciferase assay revealed that lncRNA GAS5 could interact with miR-21, and SOCS6 served as the target of miR-21. After GAS5 overexpression, the phagocytosis of RAW264.7 treated with MIP was increased whereas the chemotaxis was decreased. In contrast, the opposite results were found in RAW264.7 following GAS5 interference.

Conclusions

The present results revealed that MIP could influence RAW264.7 macrophages on phagocytic and chemotactic activities through the axis of lncRNA GAS5/miR-21/SOCS6.

Silencing lncRNA GAS5 alleviates apoptosis and fibrosis in diabetic cardiomyopathy by targeting miR-26a/b-5p

BACKGROUND

LncRNA GAS5 is associated with high glucose-induced cardiomyocyte injury, but its role in diabetic cardiomyopathy (DCM) remains unclear.

METHODS

Mice were administered with streptozotocin to construct the diabetic model (DM). Primary mouse cardiomyocytes were isolated and treated with 30 mmol/L high glucose to mimic the diabetic condition in vitro. GAS5 expression was detected by quantitative reverse transcription polymerase chain reaction. The relationship between GAS5 and miR-26a/b-5p was determined by bioinformatic prediction, luciferase reporter assay and RNA immunoprecipitation assay. The cardiac function of diabetic mice was evaluated by two-dimensional echocardiography.

RESULTS

GAS5 was significantly upregulated in diabetic cardiomyopathy both in vitro and in vivo. GAS5 knockdown and miR-26a/b-5p overexpression not only effectively attenuated myocardial fibrosis of diabetic mice in vivo but also inhibited high glucose-induced cardiomyocyte injury in vitro. miR-26a/b-5p was identified as a target of GAS5. GAS5 knockdown efficiently attenuated myocardial fibrosis and high glucose-induced cardiomyocyte injury through negatively regulating miR-26a/b-p.

CONCLUSION

Our study showed that GAS5 promotes DCM progression by regulating miR-26a/b-5p, suggesting that GAS5 might be a potential therapeutic target for DCM.

LncRNA GAS5 protects against TGF-β-induced renal fibrosis via the Smad3/miRNA-142-5p axis

Increasing evidence shows that long noncoding RNAs (lncRNAs) play an important role in kidney disease. In this study, we investigated the role of the lncRNA growth arrest-specific 5 (GAS5) in the pathogenesis of renal fibrosis. We found that GAS5 was markedly decreased in the fibrotic kidney of a unilateral ureteral obstructive nephropathy mouse model. In addition, GAS5 was expressed in mouse tubular epithelial cells (mTECs) and interstitial fibroblasts in normal renal tissue and was especially highly expressed in the cytoplasm. In vitro experiments showed that GAS5 was downregulated by transforming growth factor-β1 (TGF-β1) in a dose- and time-dependent manner. Overexpression of GAS5 blocked TGF-β1-induced collagen type I and fibronectin expression and vice versa. Mechanistic experiments revealed that Smad3 but not Smad2 drove the regulation of GAS5. More importantly, GAS5 interacted with miR-142-5p and was involved in the renoprotective effect by participating in the competing endogenous RNA network. Finally, we also found that knockdown of GAS5 promoted TGF-β1-induced mouse tubular epithelial cell apoptosis via the Smad3 pathway. Taken together, our results uncovered a lncRNA/miRNA competing endogenous RNA network-based mechanism that modulates extracellular matrix formation and cell apoptosis via the Smad3 pathway.NEW & NOTEWORTHY In this work, we mainly discuss long noncoding RNA growth arrest-specific 5 (GAS5), acting in a renoprotective role via the Smad3/miRNA-142-5p axis, that modulates extracellular matrix formation and cell apoptosis. Overexpression of GAS5 effectively blocked renal fibrosis in vitro. This study reveals that GAS5 may represent as a novel and precision therapeutic target for alleviating renal fibrosis.

LncRNA GAS5 as miR-26a-5p Sponge Regulates the PTEN/PI3K/Akt Axis and Affects Extracellular Matrix Synthesis in Degenerative Nucleus Pulposus Cells in vitro

The role of lncRNA growth arrest specific 5 (GAS5) in degenerative nucleus pulposus cell (NPC) apoptosis has been reported, but the mechanism of GAS5 in extracellular matrix (ECM) synthesis in intervertebral disc degeneration (IDD) remains unknown. We aimed to investigate the mechanism of GAS5 in ECM synthesis in degenerative NPCs. GAS5 expression was measured in degenerative NPCs (CP-H170) and normal NPCs (CP-H097). siRNA-mediated GAS5 knockdown was transfected to NPCs to detect cell viability and the expression of ECM-related genes (Collagen II, aggrecan, Collagen I, and MMP-3). Subcellular localization of GAS5 was analyzed. The downstream gene and pathway of GAS5 in degenerative NPCs were explored. As our results indicated, lncRNA GAS5 was upregulated in degenerative NPCs. Silencing GAS5 improved the viability of degenerative NPCs and increased ECM synthesis. GAS5 was mainly located in the cytoplasm of NPCs. LncRNA GAS5 sponged miR-26a-5p to regulate PTEN. Overexpression of miR-26a-5p promoted ECM synthesis in degenerative NPCs. Akt inhibitor LY294002 reversed the promotion of silencing GAS5 on ECM synthesis of degenerative NPCs. In conclusion, lncRNA GAS5 sponged miR-26a-5p to upregulate PTEN and inhibit the PI3K/Akt pathway, thus inhibiting ECM synthesis of degenerative NPCs.