TGFβ acts through PDGFRβ to activate mTORC1 via the Akt/PRAS40 axis and causes glomerular mesangial cell hypertrophy and matrix protein expression

High glucose-induced downregulation of PTEN-Long is sufficient for proximal tubular cell injury in diabetic kidney disease

During the progression of diabetic kidney disease, proximal tubular epithelial cells respond to high glucose to induce hypertrophy and matrix expansion leading to renal fibrosis. Recently, a non-canonical PTEN has been shown to be translated from an upstream initiation codon CUG (leucine) to produce a longer protein called PTEN-Long (PTEN-L). Interestingly, the extended sequence present in PTEN-L contains cell secretion/penetration signal. Role of this non-canonical PTEN-L in diabetic renal tubular injury is not known. We show that high glucose decreases expression of PTEN-L. As a mechanism of its function, we find that reduced PTEN-L activates Akt-2, which phosphorylates and inactivate tuberin and PRAS40, resulting in activation of mTORC1 in tubular cells. Antibacterial agent acriflavine and antiviral agent ATA regulate translation from CUG codon. Acriflavine and ATA, respectively, decreased and increased expression of PTEN-L to altering Akt-2 and mTORC1 activation in the absence of change in expression of canonical PTEN. Consequently, acriflavine and ATA modulated high glucose-induced tubular cell hypertrophy and lamininγ1 expression. Importantly, expression of PTEN-L inhibited high glucose-stimulated Akt/mTORC1 activity to abrogate these processes. Since PTEN-L contains secretion/penetration signals, addition of conditioned medium containing PTEN-L blocked Akt-2/mTORC1 activity. Notably, in renal cortex of diabetic mice, we found reduced PTEN-L concomitant with Akt-2/mTORC1 activation, leading to renal hypertrophy and lamininγ1 expression. These results present first evidence for involvement of PTEN-L in diabetic kidney disease.

Conversion of dendritic cells into tolerogenic or inflammatory cells depends on the activation threshold and kinetics of the mTOR signaling pathway

BACKGROUND

Restoring impaired peripheral immune tolerance is the primary challenge in treating autoimmune diseases. Our previous research demonstrated the effectiveness of small spleen peptides (SSPs), a fraction of low molecular weight proteins, in inhibiting the progression of psoriatic arthritis, even in the presence of high levels of the proinflammatory cytokine TNFα in the bloodstream. When specifically targeting dendritic cells (DCs), SSPs transform them into tolerogenic cells, which efficiently induce the development of regulatory Foxp3+ Treg cells. In this study, we provide further insights into the mechanism of action of SSPs.

RESULTS

We found that SSPs stimulate the activation of the mTOR signaling pathway in dendritic cells, albeit in a different manner than the classical immunogenic stimulus LPS. While LPS-induced activation is rapid, strong, and sustained, the activity induced by SSPs is delayed, less intense, yet still significant. These distinct patterns of activation, as measured by phosphorylation of key components of the pathway are also observed in response to other immunogenic and tolerogenic stimuli such as GM-CSF + IL-4 or IL-10 and TGFβ. The disparity in mTOR activation between immunogenic and tolerogenic stimuli is quantitative rather than qualitative. In both cases, mTOR activation primarily occurs through the PI3K/Akt signaling axis and involves ERK and GSK3β kinases, with minimal involvement of AMPK or NF-kB pathways. Furthermore, in the case of SSPs, mTOR activation seems to involve adenosine receptors. Additionally, we observed that DCs treated with SSPs exhibit an energy metabolism with high plasticity, which is typical of tolerogenic cells rather than immunogenic cells.

CONCLUSION

Hence, the decision whether dendritic cells enter an inflammatory or tolerogenic state seems to rely on varying activation thresholds and kinetics of the mTOR signaling pathway.

Exogenous PRAS40 reduces KLF4 expression and alleviates hypertrophic scar fibrosis and collagen deposition through inhibiting mTORC1

BACKGROUND

To identify the anti-fibrosis effect of PRAS40 in scar, and its potential mechanism.

METHODS

We constructed a rat model of hypertrophic scarthat was locally injected the PRAS40 overexpression adenoviruses, mTORC1 inhibitor MHY1485 and activator rapamycin, and further observed the pathological changes of skin tissue and the severity of fibrosis by HE, Masson and sirius red staining, and analyzed the deposition of a-SMA and collagen I by western blot and immunofluorescence test. Meanwhile, the co-localization of KLF4 with a-SMA and type I collagen was analyzed, as well as the regulatory effect of PRAS40 on KLF4. In addition, we also verified whether the inhibition of scar fibrosis by PRAS40 is related to mTORC1, and whether the upregulation of KLF4 is related to mTORC1.

RESULTS

The results showed that the expression of PRAS40 was low and p-PRAS40 was high in scar skin tissue. After local injection of PRAS40 overexpression adenovirus, the expression of PRAS40 in skin tissue was increased. The overexpression of PRAS40 can inhibit scar skin fibrosis and reduce the content of a-SMA and collagen I. Further mechanism analysis confirms that the inhibitory effect of PRAS40 on skin fibrosis is related to mTORC1, and PRAS40 inhibits the activation of mTORC1. The expression of KLF4 is relatively low in scar tissue. PRAS40 administration upregulated the expression of KLF4, which is related to mTORC1 CONCLUSIONS: PRAS40 significantly improves fibrosis of scar skin tissue and increases the expression of KLF4 in scars. The anti-fibrotic effect of PRAS40 depends on mTORC1.

Schwann cell derived pleiotrophin stimulates fibroblast for proliferation and excessive collagen deposition in plexiform neurofibroma

Neurofibromatosis type 1 associated plexiform neurofibroma (pNF) is characterized by abundant fibroblasts and dense collagen, yet the intricate interactions between tumor-origin cells (Schwann cells) and neurofibroma-associated fibroblasts (NFAFs) remain elusive. Employing single-cell RNA sequencing on human pNF samples, we generated a comprehensive transcriptomics dataset and conducted cell-cell communication analysis to unravel the molecular dynamics between Schwann cells and NFAFs. Our focus centered on the pleiotrophin (PTN)/nucleolin (NCL) axis as a pivotal ligand-receptor pair orchestrating this interaction. Validation of PTN involvement was affirmed through coculture models and recombinant protein experiments. Functional and mechanistic investigations, employing assays such as CCK8, EdU, Western Blot, ELISA, Hydroxyproline Assay, and Human phospho-kinase array, provided critical insights. We employed siRNA or inhibitors to intercept the PTN/NCL/proline-rich Akt substrate of 40 kDa (PRAS40) axis, validating the associated molecular mechanism. Our analysis highlighted a subset of Schwann cells closely linked to collagen deposition, underscoring their significance in pNF development. The PTN/NCL axis emerged as a key mediator of the Schwann cell-NFAF interaction. Furthermore, our study demonstrated that elevated PTN levels enhanced NFAF proliferation and collagen synthesis, either independently or synergistically with TGF-β1 in vitro. Activation of the downstream molecule PRAS40 was noted in NFAFs upon PTN treatment. Crucially, by targeting NCL and PRAS40, we successfully reversed collagen synthesis within NFAFs. In conclusion, our findings unveil the pivotal role of the PTN/NCL/PRAS40 axis in driving pNF development by promoting NFAFs proliferation and function. Targeting this pathway emerges as a potential therapeutic strategy for pNF. This study contributes novel insights into the molecular mechanisms governing pNF pathogenesis.

The level of protein in the maternal murine diet modulates the facial appearance of the offspring via mTORC1 signaling

The development of craniofacial skeletal structures is fascinatingly complex and elucidation of the underlying mechanisms will not only provide novel scientific insights, but also help develop more effective clinical approaches to the treatment and/or prevention of the numerous congenital craniofacial malformations. To this end, we performed a genome-wide analysis of RNA transcription from non-coding regulatory elements by CAGE-sequencing of the facial mesenchyme of human embryos and cross-checked the active enhancers thus identified against genes, identified by GWAS for the normal range human facial appearance. Among the identified active cis-enhancers, several belonged to the components of the PI3/AKT/mTORC1/autophagy pathway. To assess the functional role of this pathway, we manipulated it both genetically and pharmacologically in mice and zebrafish. These experiments revealed that mTORC1 signaling modulates craniofacial shaping at the stage of skeletal mesenchymal condensations, with subsequent fine-tuning during clonal intercalation. This ability of mTORC1 pathway to modulate facial shaping, along with its evolutionary conservation and ability to sense external stimuli, in particular dietary amino acids, indicate that the mTORC1 pathway may play a role in facial phenotypic plasticity. Indeed, the level of protein in the diet of pregnant female mice influenced the activity of mTORC1 in fetal craniofacial structures and altered the size of skeletogenic clones, thus exerting an impact on the local geometry and craniofacial shaping. Overall, our findings indicate that the mTORC1 signaling pathway is involved in the effect of environmental conditions on the shaping of craniofacial structures.

Review of molecular biological research on the treatment of membranous nephropathy with Tripterygium glycosides based on TCM theory

To explore the mechanism of Tripterygium wilfordii polyglycoside (TWP) in the treatment of membranous nephropathy (MN) by network pharmacology. TCMSP and DrugBank databases were used to screen the main targets of the main active components of Tripterygium glycosides, and OMIM and Gene Cards databases were used to search the gene targets of MN. UniProt database was used to normalize all the targets to get the intersection targets of TGs and MNs. Synergistic genes were uploaded to the STRING platform to construct a protein-protein interaction network and screen related core targets. Gene Ontology and Kyoto Genome Encyclopedia analyses of core targets were performed using the DAVID database. AutoDockTools software was used to verify the molecular docking between the active components of TGs and the synergistic genes. We identified 126 potential targets for the active component of Tripterygium glycosides, 584 MN-associated disease targets, and 28 co-acting genes. It mainly involves AGE-RAGE signaling pathway, lipid and atherosclerosis, IL-17 signaling pathway, fluid shear stress and atherosclerosis, NF-kappa B signaling pathway and other pathways and biological pathways in diabetic complications. The active component of that Tripterygium glycosides and the active site of the synergistic core target can the bond energy is less than -5kJ/mol. Tripterygium glycosides can regulate the release of inflammatory factors to treat MN through multiple active components, multiple disease targets, multiple biological pathways and multiple pathways, which provides a basis for broadening the clinical use of traditional Chinese medicine in the treatment of MN.

TGFβ instructs mTORC2 to activate PKCβII for increased TWIST1 expression in proximal tubular epithelial cell injury

The plasticity of proximal tubular epithelial cells in response to TGFβ contributes to the expression of TWIST1 to drive renal fibrosis. The mechanism of TWIST1 expression is not known. We show that both PI3 kinase and its target mTORC2 increase TGFβ-induced TWIST1 expression. TGFβ enhances phosphorylation on Ser-660 in the protein kinase C βII (PKCβII) hydrophobic motif site. Remarkably, phosphorylation-deficient PKCβIIS660A, kinase-dead PKCβII, and PKCβII knockdown blocked TWIST1 expression by TGFβ. Inhibition of TWIST1 arrested TGFβ-induced tubular cell hypertrophy and the expression of fibronectin, collagen I (α2), and α-smooth muscle actin. By contrast, TWIST1 overexpression induced these pathologies. Interestingly, the inhibition of PKCβII reduced these phenomena, which were countered by the expression of TWIST1. These results provide the first evidence for the involvement of the mTORC2-PKCβII axis in TWIST1 expression to promote tubular cell pathology.

New insights into fibrotic signaling in renal cell carcinoma

Fibrotic signaling plays a pivotal role in the development and progression of solid cancers including renal cell carcinoma (RCC). Intratumoral fibrosis (ITF) and pseudo-capsule (PC) fibrosis are significantly correlated to the disease progression of renal cell carcinoma. Targeting classic fibrotic signaling processes such as TGF-β signaling and epithelial-to-mesenchymal transition (EMT) shows promising antitumor effects both preclinically and clinically. Therefore, a better understanding of the pathogenic mechanisms of fibrotic signaling in renal cell carcinoma at molecular resolution can facilitate the development of precision therapies against solid cancers. In this review, we systematically summarized the latest updates on fibrotic signaling, from clinical correlation and molecular mechanisms to its therapeutic strategies for renal cell carcinoma. Importantly, we examined the reported fibrotic signaling on the human renal cell carcinoma dataset at the transcriptome level with single-cell resolution to assess its translational potential in the clinic.

Analysis of the potential molecular biology of triptolide in the treatment of diabetic nephropathy: A narrative review

OBJECTIVE

To explore the potential mechanism of triptolide in diabetic nephropathy (DN) treatment using network pharmacology.

METHODS

The main targets of triptolide were screened using the TCMSP, DrugBank, and NCBI databases, and gene targets of DN were searched using the DrugBank, DisGeNET, TTD, and OMIM databases. All of the above targets were normalized using the UniProt database to obtain the co-acting genes. The co-acting genes were uploaded to the STRING platform to build a protein-protein interaction network and screen the core acting targets. Gene ontology and Kyoto encyclopedia of genes and genomes analyses of the core targets were performed using Metascape. Molecular docking validation of triptolide with the co-acting genes was performed using the Swiss Dock platform.

RESULTS

We identified 76 potential target points for triptolide, 693 target points for DN-related diseases, and 24 co-acting genes. The main pathways and biological processes involved are lipids and atherosclerosis, IL-18 signaling pathway, TWEAK signaling pathway, response to oxidative stress, hematopoietic function, and negative regulation of cell differentiation. Both triptolide and the active site of the core target genes can form more than 2 hydrogen bonds, and the bond energy is less than -5kJ/mol. Bioinformatics analysis showed that triptolide had a regulatory effect on most of the core target genes that are aberrantly expressed in DKD.

CONCLUSION

Triptolide may regulate the body's response to cytokines, hormones, oxidative stress, and apoptosis signaling pathways in DN treatment by down-regulating Casp3, Casp8, PTEN, GSA3B and up-regulating ESR1, and so forth.

Inhibition of platelet-derived growth factor pathway suppresses tubulointerstitial injury in renal congestion

OBJECTIVE

Increased central venous pressure in congestive heart failure is responsible for renal dysfunction, which is mediated by renal venous congestion. Pericyte detachment from capillaries after renal congestion might trigger renal fibrogenesis via pericyte-myofibroblast transition (PMT). Platelet-derived growth factor receptors (PDGFRs), which are PMT indicators, were upregulated in our recently established renal congestion model. This study was designed to determine whether inhibition of the PDGFR pathway could suppress tubulointerstitial injury after renal congestion.

METHODS

The inferior vena cava between the renal veins was ligated in male Sprague-Dawley rats, inducing congestion only in the left kidney. Imatinib mesylate or vehicle were injected intraperitoneally daily from 1 day before the operation. Three days after the surgery, the effect of imatinib was assessed by physiological, morphological and molecular methods. The inhibition of PDGFRs against transforming growth factor-β1 (TGFB1)-induced fibrosis was also tested in human pericyte cell culture.

RESULTS

Increased kidney weight and renal fibrosis were observed in the congested kidneys. Upstream inferior vena cava (IVC) pressure immediately increased to around 20 mmHg after IVC ligation in both the imatinib and saline groups. Although vasa recta dilatation and pericyte detachment under renal congestion were maintained, imatinib ameliorated the increased kidney weight and suppressed renal fibrosis around the vasa recta. TGFB1-induced elevation of fibrosis markers in human pericytes was suppressed by PDGFR inhibitors at the transcriptional level.

CONCLUSION

The activation of the PDGFR pathway after renal congestion was responsible for renal congestion-induced fibrosis. This mechanism could be a candidate therapeutic target for renoprotection against renal congestion-induced tubulointerstitial injury.

Oncoprotein DJ-1 interacts with mTOR complexes to effect transcription factor Hif1α-dependent expression of collagen I (α2) during renal fibrosis

Proximal tubular epithelial cells respond to transforming growth factor β (TGFβ) to synthesize collagen I (α2) during renal fibrosis. The oncoprotein DJ-1 has previously been shown to promote tumorigenesis and prevent apoptosis of dopaminergic neurons; however, its role in fibrosis signaling is unclear. Here, we show TGFβ-stimulation increased expression of DJ-1, which promoted noncanonical mTORC1 and mTORC2 activities. We show DJ-1 augmented the phosphorylation/activation of PKCβII, a direct substrate of mTORC2. In addition, coimmunoprecipitation experiments revealed association of DJ-1 with Raptor and Rictor, exclusive subunits of mTORC1 and mTORC2, respectively, as well as with mTOR kinase. Interestingly, siRNAs against DJ-1 blocked TGFβ-stimulated expression of collagen I (α2), while expression of DJ-1 increased expression of this protein. In addition, expression of dominant negative PKCβII and siRNAs against PKCβII significantly inhibited TGFβ-induced collagen I (α2) expression. In fact, constitutively active PKCβII abrogated the effect of siRNAs against DJ-1, suggesting a role of PKCβII downstream of this oncoprotein. Moreover, we demonstrate expression of collagen I (α2) stimulated by DJ-1 and its target PKCβII is dependent on the transcription factor hypoxia-inducible factor 1α (Hif1α). Finally, we show in the renal cortex of diabetic rats that increased TGFβ was associated with enhanced expression of DJ-1 and activation of mTOR and PKCβII, concomitant with increased Hif1α and collagen I (α2). Overall, we identified that DJ-1 affects TGFβ-induced expression of collagen I (α2) via an mTOR-, PKCβII-, and Hif1α-dependent mechanism to regulate renal fibrosis.

Lessons from neonatal β-cell epigenomic for diabetes prevention and treatment

Pancreatic β-cell expansion and functional maturation during the birth-to-weaning period plays an essential role in the adaptation of plasma insulin levels to metabolic needs. These events are driven by epigenetic programs triggered by growth factors, hormones, and nutrients. These mechanisms operating in the neonatal period can be at least in part reactivated in adult life to increase the functional β-cell mass and face conditions of increased insulin demand such as obesity or pregnancy. In this review, we will highlight the importance of studying these signaling pathways and epigenetic programs to understand the causes of different forms of diabetes and to permit the design of novel therapeutic strategies to prevent and treat this metabolic disorder affecting hundreds of millions of people worldwide.

PGK1 represses autophagy-mediated cell death to promote the proliferation of liver cancer cells by phosphorylating PRAS40

Autophagy predominantly promotes cell survival by recycling cell components, while it kills cells in specific contexts. Cell death related to autophagy plays important roles in multiple physiological and pathological situations including tumorigenesis, and the mechanism needs to be defined further. PRAS40 was found to be crucial in various cancers, and phosphorylation was reported to be involved in autophagy inhibition in monocytes. However, the detailed role of PRAS40 in autophagy and the relationship to tumorigenesis remain largely unknown. Herein we screened the binding partners of PRAS40, and found that PRAS40 interacted with Phosphoglycerate kinase 1 (PGK1). PGK1 phosphorylated PRAS40 at Threonine 246, which could be inhibited by blocking the interaction. Both in vitro and in vivo results revealed that PRAS40 mediated PGK1-induced cell growth. By tracing the mechanism, we found that PGK1 suppressed autophagy-mediated cell death, in which PRAS40 was crucial. Thus PGK1 phosphorylates PRAS40 to repress autophagy-mediated cell death under normoxia, promoting cellular proliferation. The binding of PGK1 to PRAS40 was transferred to Beclin1 under hypoxia, resulting in the increase of Beclin1 phosphorylation. These results suggest a novel model of tumorigenesis, in which PGK1 switches between repressing autophagy-mediated cell death via PRAS40 and inducing autophagy through Beclin1 according to the environmental oxygen level. Our study is anticipated to be able to offer novel insights in understanding PGK1/PRAS40 signaling hyperactivated cancers.

Gene expression profiles of diabetic kidney disease and neuropathy in eNOS knockout mice: Predictors of pathology and RAS blockade effects

Diabetic kidney disease (DKD) and diabetic peripheral neuropathy (DPN) are two common diabetic complications. However, their pathogenesis remains elusive and current therapies are only modestly effective. We evaluated genome-wide expression to identify pathways involved in DKD and DPN progression in db/db eNOS-/- mice receiving renin-angiotensin-aldosterone system (RAS)-blocking drugs to mimic the current standard of care for DKD patients. Diabetes and eNOS deletion worsened DKD, which improved with RAS treatment. Diabetes also induced DPN, which was not affected by eNOS deletion or RAS blockade. Given the multiple factors affecting DKD and the graded differences in disease severity across mouse groups, an automatic data analysis method, SOM, or self-organizing map was used to elucidate glomerular transcriptional changes associated with DKD, whereas pairwise bioinformatic analysis was used for DPN. These analyses revealed that enhanced gene expression in several pro-inflammatory networks and reduced expression of development genes correlated with worsening DKD. Although RAS treatment ameliorated the nephropathy phenotype, it did not alter the more abnormal gene expression changes in kidney. Moreover, RAS exacerbated expression of genes related to inflammation and oxidant generation in peripheral nerves. The graded increase in inflammatory gene expression and decrease in development gene expression with DKD progression underline the potentially important role of these pathways in DKD pathogenesis. Since RAS blockers worsened this gene expression pattern in both DKD and DPN, it may partly explain the inadequate therapeutic efficacy of such blockers.

Targeting PRAS40: a novel therapeutic strategy for human diseases

Proline-rich Akt substrate of 40 kD (PRAS40) is not only the substrate of protein kinase B (PKB/Akt), but also the binding protein of 14-3-3 protein. PRAS40 is expressed in a variety of tissues in vivo and has multiple phosphorylation sites, which its activity is closely related to phosphorylation. Studies have shown that PRAS40 is involved in regulating cell growth, cell apoptosis, oxidative stress, autophagy and angiogenesis, as well as various of signalling pathways such as mammalian target of mammalian target rapamycin (mTOR), protein kinase B (PKB/Akt), nuclear factor kappa-B(NF-κB), proto-oncogene serine/threonine-protein kinase PIM-1(PIM1) and pyruvate kinase M2 (PKM2). The interactive roles between PRAS40 and these signal proteins were analysed by bioinformatics in this paper. Moreover, it is of great necessity for analyse the important roles of PRAS40 in some human diseases including cardiovascular disease, ischaemia-reperfusion injury, neurodegenerative disease, cancer, diabetes and other metabolic diseases. Finally, the effects of miRNA on the regulation of PRAS40 function and the occurrence and development of PRAS40-related diseases are also discussed. Overall, PRAS40 is expected to be a drug target and provide a new treatment strategy for human diseases.

High glucose-stimulated enhancer of zeste homolog-2 (EZH2) forces suppression of deptor to cause glomerular mesangial cell pathology

Function of mTORC1 and mTORC2 has emerged as a driver of mesangial cell pathologies in diabetic nephropathy. The mechanism of mTOR activation is poorly understood in this disease. Deptor is a constitutive subunit and a negative regulator of both mTOR complexes. Mechanistic investigation in mesangial cells revealed that high glucose decreased the expression of deptor concomitant with increased mTORC1 and mTORC2 activities, induction of hypertrophy and, expression of fibronectin and PAI-1. shRNAs against deptor mimicked these pathologic outcomes of high glucose. Conversely, overexpression of deptor significantly inhibited all effects of high glucose. To determine the mechanism of deptor suppression, we found that high glucose significantly increased the expression of EZH2, resulting in lysine-27 tri-methylation of histone H3 (H3K27Me3). Employing approaches including pharmacological inhibition, shRNA-mediated downregulation and overexpression of EZH2, we found that EZH2 regulates high glucose-induced deptor suppression along with activation of mTOR, mesangial cell hypertrophy and fibronectin/PAI-1 expression. Moreover, expression of hyperactive mTORC1 reversed shEZH2-mediated inhibition of hypertrophy and expression of fibronectin and PAI-1 by high glucose. Finally, in renal cortex of diabetic mice, we found that enhanced expression of EZH2 is associated with decreased deptor levels and increased mTOR activity and, expression of fibronectin and PAI-1. Together, our findings provide a novel mechanism for mTOR activation via EZH2 to induce mesangial cell hypertrophy and matrix expansion during early progression of diabetic nephropathy. These results suggest a strategy for leveraging the intrinsic effect of deptor to suppress mTOR activity via reducing EZH2 as a novel therapy for diabetic nephropathy.

MiR-1297 attenuates high glucose-induced injury in HK-2 cells via targeting COL1A2

BACKGROUND

In this study, we aimed to explore whether COL1A2 and miR-1297 participated in the progression of diabetic nephropathy (DN) in vitro and classified the underlying mechanisms.

METHODS

d-Glucose (30 mM; high glucose, HG)-stimulated HK-2 cells were used to mimic DN condition. RNA and non-coding RNA profiles were from Gene Expression Omnibus (GEO) database. The interaction between miR-1297 and COL1A2 was measured by dual-luciferase reporter assay. Gene Set Enrichment Analysis (GSEA) method was conducted to analyse COL1A2-associated signalling pathways. The role of miR-1297/COL1A2 in biological behaviours of HG-induced HK-2 cells were analysed by cell counting kit-8 and apoptosis assays.

RESULTS

Bioinformatics analysis revealed that COL1A2 was up-regulated in DN tissues. We predicted and verified miR-1297 as the regulatory miRNA of COL1A2, and the expression of miR-1297 was decreased in DN tissues and HG-stimulated HK-2 cells. Overexpression of miR-1297 could promote cell proliferation and inhibit apoptosis to protect HK-2 cells from HG-induced damage. And knockdown of COL1A2 enhanced the protective effects of miR-1297 on HG-stimulated HK-2 cells. GSEA results revealed that several inflammatory pathways were enriched in COL1A2 high-expression group. Meanwhile, transfection of miR-1297 reduced the phosphorylation of NFκB and expression of three important pro-inflammatory genes including cytokine CCL5, adhesion molecules ICAM1 and VCAM1 via targeting COL1A2. These results suggested that miR-1297 protected HG-treated HK-2 cells probably through suppressing inflammation via targeting COL1A2.

CONCLUSION

This study sheds a light on the role miR-1297/COL1A2 in DN progression and provides a novel promising therapy strategy for suppressing DN progression.

SEPHS1 promotes SMAD2/3/4 expression and hepatocellular carcinoma cells invasion

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the common cancers that are very aggressive. The secreted cytokine transforming growth factor-β (TGF-β) promotes cancer metastasis by multiple mechanisms such as epithelial-mesenchymal transition and immune evasion. The canonical TGF-β signaling is largely mediated by smooth muscle actin/mothers against decapentaplegic (SMAD) proteins. The current study aims to explore the regulation of TGF-β/SMAD signaling by selenophosphate synthetase 1 (SEPHS1).

METHODS

Immunohistochemistry was used to detect the expression of SEPHS1 in HCC and adjacent liver tissues. Western blotting and quantitative reverse-transcription PCR were used to detect the protein and mRNA levels in HCC cell lines. Cell migration and invasion were determined by transwell assay. Bioinformatic analysis was conducted to determine SEPHS1 expression in HCC and its correlation with the survival of HCC patients.

RESULTS

Here we report that SEPHS1 is a positive regulator of SMAD proteins. SEPHS1 expression is up-regulated in HCC compared with adjacent liver tissues. SEPHS1 knockdown leads to decreased expression of SMAD2/3/4 and mesenchymal markers including snail, slug and N-cadherin in HCC cells. Furthermore, SEPHS1 knockdown results in a decrease in HCC cells migration and invasion, and suppresses the stimulation of HCC cells migration and invasion by TGF-β. Overexpression of SEPHS1 in HCC cells promotes cell invasion, which can be abrogated by SMAD3 knockdown. Lastly, higher expression of SEPHS1 is correlated with poor prognosis in HCC patients, as manifested by decreased overall survival and disease-free survival.

CONCLUSIONS

SEPHS1 is a positive regulator of TGF-β/SMAD signaling that is up-regulated in HCC. Increased SEPHS1 expression may indicate poor prognosis for patients with HCC.