DEK‐targeting aptamer DTA‐64 attenuates bronchial EMT‐mediated airway remodelling by suppressing TGF‐β1/Smad,MAPK and PI3K signalling pathway in asthma

This study is to investigate the inhibitory effects and mechanisms of DEK‐targeting aptamer (DTA‐64) on epithelial mesenchymaltransition (EMT)‐mediated airway remodelling in mice and human bronchial epithelial cell line BEAS‐2B. In the ovalbumin (OVA)‐induced asthmatic mice, DTA‐64 significantly reduced the infiltration of eosinophils and neutrophils in lung tissue, attenuated the airway resistance and the proliferation of goblet cells. In addition, DTA‐64 reduced collagen deposition, transforming growth factor 1 (TGF‐β1) level in BALF and IgE levels in serum, balanced Th1/Th2/Th17 ratio, and decreased mesenchymal proteins (vimentin and α‐SMA), as well as weekend matrix metalloproteinases (MMP‐2 and MMP‐9) and NF‐κB p65 activity. In the in vitro experiments, we used TGF‐β1 to induce EMT in the human epithelial cell line BEAS‐2B. DEK overexpression (ovDEK) or silencing (shDEK) up‐regulated or down‐regulated TGF‐β1 expression, respectively, on the contrary, TGF‐β1 exposure had no effect on DEK expression. Furthermore, ovDEK and TGF‐β1 synergistically promoted EMT, whereas shDEK significantly reduced mesenchymal markers and increased epithelial markers, thus inhibiting EMT. Additionally, shDEK inhibited key proteins in TGF‐β1‐mediated signalling pathways, including Smad2/3, Smad4, p38 MAPK, ERK1/2, JNK and PI3K/AKT/mTOR. In conclusion, the effects of DTA‐64 against EMT of asthmatic mice and BEAS‐2B might partially be achieved through suppressing TGF‐β1/Smad, MAPK and PI3K signalling pathways. DTA‐64 may be a new therapeutic option for the management of airway remodelling in asthma patients.     

MicroRNA‐411‐3p inhibits bleomycin‐induced skin fibrosis by regulating transforming growth factor‐β/Smad ubiquitin regulatory factor‐2 signalling

Skin fibrosis, which is characterized by fibroblast proliferation and increased extracellular matrix, has no effective treatment. An increasing number of studies have shown that microRNAs (miRNAs/miRs) participate in the mechanism of skin fibrosis, such as in limited cutaneous systemic sclerosis and pathological scarring. The objective of the present study was to determine the role of miR‐411‐3p in bleomycin (BLM)‐induced skin fibrosis and skin fibroblast transformation. Using Western blot analysis and real‐time quantitative polymerase chain reaction assess the expression levels of miR‐411‐3p, collagen (COLI) and transforming growth factor (TGF)‐β/Smad ubiquitin regulatory factor (Smurf)‐2/Smad signalling factors both in vitro and in vivo with or without BLM. To explore the regulatory relationship between miR‐411‐3p and Smurf2, we used the luciferase reporter assay. Furthermore, miR‐411‐3p overexpression was identified in vitro and in vivo via transfection with Lipofectamine 2000 reagent and injection. Finally, we tested the dermal layer of the skin using haematoxylin and eosin and Van Gieson''s staining. We found that miR‐411‐3p expression was decreased in bleomycin (BLM)‐induced skin fibrosis and fibroblasts. However, BLM accelerated transforming growth factor (TGF)‐β signalling and collagen production. Overexpression of miR‐411‐3p inhibited the expression of collagen, F‐actin and the TGF‐β/Smad signalling pathway factors in BLM‐induced skin fibrosis and fibroblasts. In addition, miR‐411‐3p inhibited the target Smad ubiquitin regulatory factor (Smurf)‐2. Furthermore, Smurf2 was silenced, which attenuated the expression of collagen via suppression of the TGF‐β/Smad signalling pathway. We demonstrated that miR‐411‐3p exerts antifibrotic effects by inhibiting the TGF‐β/Smad signalling pathway via targeting of Smurf2 in skin fibrosis.     

Polydatin inhibits ZEB1‐invoked epithelial‐mesenchymal transition in fructose‐induced liver fibrosis

High fructose intake is a risk factor for liver fibrosis. Polydatin is a main constituent of the rhizome of Polygonum cuspidatum, which has been used in traditional Chinese medicine to treat liver fibrosis. However, the underlying mechanisms of fructose‐driven liver fibrosis as well as the actions of polydatin are not fully understood. In this study, fructose was found to promote zinc finger E‐box binding homeobox 1 (ZEB1) nuclear translocation, decrease microRNA‐203 (miR‐203) expression, increase survivin, activate transforming growth factor β1 (TGF‐β1)/Smad signalling, down‐regulate E‐cadherin, and up‐regulate fibroblast specific protein 1 (FSP1), vimentin, N‐cadherin and collagen I (COL1A1) in rat livers and BRL‐3A cells, in parallel with fructose‐induced liver fibrosis. Furthermore, ZEB1 nuclear translocation‐mediated miR‐203 low‐expression was found to target survivin to activate TGF‐β1/Smad signalling, causing the EMT in fructose‐exposed BRL‐3A cells. Polydatin antagonized ZEB1 nuclear translocation to up‐regulate miR‐203, subsequently blocked survivin‐activated TGF‐β1/Smad signalling, which were consistent with its protection against fructose‐induced EMT and liver fibrosis. These results suggest that ZEB1 nuclear translocation may play an essential role in fructose‐induced EMT in liver fibrosis by targeting survivin to activate TGF‐β1/Smad signalling. The suppression of ZEB1 nuclear translocation by polydatin may be a novel strategy for attenuating the EMT in liver fibrosis associated with high fructose diet.     

Pirfenidone modulates macrophage polarization and ameliorates radiation‐induced lung fibrosis by inhibiting the TGF‐β1/Smad3 pathway

Radiation‐induced lung injury (RILI) mainly contributes to the complications of thoracic radiotherapy. RILI can be divided into radiation pneumonia (RP) and radiation‐induced lung fibrosis (RILF). Once RILF occurs, patients will eventually develop irreversible respiratory failure; thus, a new treatment strategy to prevent RILI is urgently needed. This study explored the therapeutic effect of pirfenidone (PFD), a Food and Drug Administration (FDA)‐approved drug for (IPF) treatment, and its mechanism in the treatment of RILF. In vivo, C57BL/6 mice received a 50 Gy dose of X‐ray radiation to the whole thorax with or without the administration of PFD. Collagen deposition and fibrosis in the lung were reversed by PFD treatment, which was associated with reduced M2 macrophage infiltration and inhibition of the transforming growth factor‐β1 (TGF‐β1)/Drosophila mothers against the decapentaplegic 3 (Smad3) signalling pathway. Moreover, PFD treatment decreased the radiation‐induced expression of TGF‐β1 and phosphorylation of Smad3 in alveolar epithelial cells (AECs) and vascular endothelial cells (VECs). Furthermore, IL‐4–induced M2 macrophage polarization and IL‐13–induced M2 macrophage polarization were suppressed by PFD treatment in vitro, resulting in reductions in the release of arginase‐1 (ARG‐1), chitinase 3‐like 3 (YM‐1) and TGF‐β1. Notably, the PFD‐induced inhibitory effects on M2 macrophage polarization were associated with downregulation of nuclear factor kappa‐B (NF‐κB) p50 activity. Additionally, PFD could significantly inhibit ionizing radiation‐induced chemokine secretion in MLE‐12 cells and consequently impair the migration of RAW264.7 cells. PFD could also eliminate TGF‐β1 from M2 macrophages by attenuating the activation of TGF‐β1/Smad3. In conclusion, PFD is a potential therapeutic agent to ameliorate fibrosis in RILF by reducing M2 macrophage infiltration and inhibiting the activation of TGF‐β1/Smad3.     

α‐synuclein suppresses microglial autophagy and promotes neurodegeneration in a mouse model of Parkinson’s disease

The cell‐to‐cell transfer of α‐synuclein (α‐Syn) greatly contributes to Parkinson''s disease (PD) pathogenesis and underlies the spread of α‐Syn pathology. During this process, extracellular α‐Syn can activate microglia and neuroinflammation, which plays an important role in PD. However, the effect of extracellular α‐Syn on microglia autophagy is poorly understood. In the present study, we reported that extracellular α‐Syn inhibited the autophagy initiation, as indicated by LC3‐II reduction and p62 protein elevation in BV2 and cultured primary microglia. The in vitro findings were verified in microglia‐enriched population isolated from α‐Syn‐overexpressing mice induced by adeno‐associated virus (AAV2/9)‐encoded wildtype human α‐Syn injection into the substantia nigra (SN). Mechanistically, α‐Syn led to microglial autophagic impairment through activating toll‐like receptor 4 (Tlr4) and its downstream p38 and Akt‐mTOR signaling because Tlr4 knockout and inhibition of p38, Akt as well as mTOR prevented α‐Syn‐induced autophagy inhibition. Moreover, inhibition of Akt reversed the mTOR activation but failed to affect p38 phosphorylation triggered by α‐Syn. Functionally, the in vivo evidence showed that lysozyme 2 Cre (Lyz2 ^cre)‐mediated depletion of autophagy‐related gene 5 (Atg5) in microglia aggravated the neuroinflammation and dopaminergic neuron losses in the SN and exacerbated the locomotor deficit in α‐Syn‐overexpressing mice. Taken together, the results suggest that extracellular α‐Syn, via Tlr4‐dependent p38 and Akt‐mTOR signaling cascades, disrupts microglial autophagy activity which synergistically contributes to neuroinflammation and PD development.     

Induction of γδT cells from HSC‐enriched BMCs co‐cultured with iPSC‐derived thymic epithelial cells

T cells bearing γδ antigen receptors have been investigated as potential treatments for several diseases, including malignant tumours. However, the clinical application of γδT cells has been hampered by their relatively low abundance in vivo and the technical difficulty of inducing their differentiation from hematopoietic stem cells (HSCs) in vitro. Here, we describe a novel method for generating mouse γδT cells by co‐culturing HSC‐enriched bone marrow cells (HSC‐eBMCs) with induced thymic epithelial cells (iTECs) derived from induced pluripotent stem cells (iPSCs). We used BMCs from CD45.1 congenic C57BL/6 mice to distinguish them from iPSCs, which expressed CD45.2. We showed that HSC‐eBMCs and iTECs cultured with IL‐2 + IL‐7 for up to 21 days induced CD45.1⁺ γδT cells that expressed a broad repertoire of Vγ and Vδ T‐cell receptors. Notably, the induced lymphocytes contained few or no αβT cells, NK1.1⁺ natural killer cells, or B220⁺ B cells. Adoptive transfer of the induced γδT cells to leukemia‐bearing mice significantly reduced tumour growth and prolonged mouse survival with no obvious side effects, such as tumorigenesis and autoimmune diseases. This new method suggests that it could also be used to produce human γδT cells for clinical applications.     

IFN‐γ+IL‐17+Th17 cells regulate fibrosis through secreting IL‐21 in systemic scleroderma

This study aimed to explore the function of IFN‐γ⁺IL‐17⁺Th17 cells on fibrosis in systemic scleroderma (SSc). Blood and skin samples were collected from 20 SSc cases and 10 healthy individuals. The percentage of IFN‐γ⁺IL‐17⁺Th17 cells was detected using flow cytometry. The in vitro induction of IFN‐γ⁺IL‐17⁺Th17 cells was performed adopting PHA and rIL‐12. Gene expression was detected via quantitative real‐time polymerase chain reaction (qRT‐PCR), whereas western blot analysis was adopted for protein analysis. The distribution of IFN‐γ⁺IL‐17⁺Th17 cells was significantly increased in SSc cases and positively correlated with SSc stages (P = .031), disease duration (P = .016), activity (P = .025) and skin scores (P < .001). In vitro, IFN‐γ⁺IL‐17⁺Th17 cells could promote the expressions of α‐SMA and COL1A1, revealing increased fibroblasts’ proliferation and enhanced collagen‐secreting capacity. In addition, IL‐21 expression was significantly increased in co‐culture medium of IFN‐γ⁺IL‐17⁺Th17 cells and fibroblasts (P < .001). IL‐21 neutralizer treatment resulted in the down‐regulation of α‐SMA and COL1A1. IL‐21 was confirmed as an effector of IFN‐γ⁺IL‐17⁺Th17 cells in fibrosis process. The distribution of IFN‐γ⁺IL‐17⁺Th17 cells was significantly increased in SSc cases and positively correlated with disease activity. IFN‐γ⁺IL‐17⁺Th17 cells could promote fibroblast proliferation and enhance collagen‐secreting ability via producing IL‐21, thus contributing to fibrosis in SSc.     

Newly designed Protein Transduction Domain (PTD)‐mediated BMP‐7 is a potential therapeutic for peritoneal fibrosis

While the bone morphogenetic protein‐7 (BMP‐7) is a well‐known therapeutic growth factor reverting many fibrotic diseases, including peritoneal fibrosis by peritoneal dialysis (PD), soluble growth factors are largely limited in clinical applications owing to their short half‐life in clinical settings. Recently, we developed a novel drug delivery model using protein transduction domains (PTD) overcoming limitation of soluble recombinant proteins, including bone morphogenetic protein‐7 (BMP‐7). This study aims at evaluating the therapeutic effects of PTD‐BMP‐7 consisted of PTD and full‐length BMP‐7 on epithelial‐mesenchymal transition (EMT)‐related fibrosis. Human peritoneal mesothelial cells (HPMCs) were then treated with TGF‐β1 or TGF‐β1 + PTD‐BMP‐7. Peritoneal dialysis (PD) catheters were inserted into Sprague‐Dawley rats, and these rats were infused intra‐peritoneally with saline, peritoneal dialysis fluid (PDF) or PDF + PTD‐BMP‐7. In vitro, TGF‐β1 treatment significantly increased fibronectin, type I collagen, α‐SMA and Snail expression, while reducing E‐cadherin expression in HPMCs (P < .001). PTD‐BMP‐7 treatment ameliorated TGF‐β1‐induced fibronectin, type I collagen, α‐SMA and Snail expression, and restored E‐cadherin expression in HPMCs (P < .001). In vivo, the expressions of EMT‐related molecules and the thickness of the sub‐mesothelial layer were significantly increased in the peritoneum of rats treated with PDF, and these changes were significantly abrogated by the intra‐peritoneal administration of PTD‐BMP‐7. PTD‐BMP‐7 treatment significantly inhibited the progression of established PD fibrosis. These findings suggest that PTD‐BMP‐7, as a prodrug of BMP‐7, can be an effective therapeutic agent for peritoneal fibrosis in PD patients.     

Knockdown of circular RNA VANGL1 inhibits TGF‐β‐induced epithelial‐mesenchymal transition in melanoma cells by sponging miR‐150‐5p

Melanoma is one of the most aggressive and life‐threatening skin cancers, and in this research, we aimed to explore the functional role of circular RNA VANGL1 (circVANGL1) in melanoma progression. The expression levels of circVANGL1 were observed to be significantly increased in clinical melanoma tissues and cell lines. Moreover, circVANGL1 knockdown suppressed, while circVANGL1 overexpression promoted the proliferation, migration and invasion abilities of melanoma cells. Further investigations confirmed the direct binding relation between circVANGL1 and miR‐150‐5p in melanoma, and restoration of miR‐150‐5p blocked the effects of circVANGL1 overexpression in melanoma cells. We further found that circVANGL1 was up‐regulated by TGF‐β treatment, and the enhanced EMT of TGF‐β‐treated melanoma cells was blocked by circVANGL1 knockdown. In conclusion, these results indicated that circVANGL1 might serve as a promising therapeutic target for melanoma.     

Naa10p and IKKα interaction regulates EMT in oral squamous cell carcinoma via TGF‐β1/Smad pathway

Epithelial‐mesenchymal transition (EMT) has been contributed to increase migration and invasion of cancer cells. However, the correlate of Naa10p and IKKα with EMT in oral squamous cell carcinoma (OSCC) is not yet fully understood. In our present study, we found N‐α‐acetyltransferase 10 protein (Naa10p) and IκB kinase α (IKKα) were abnormally abundant in oral squamous cell carcinoma (OSCC). Bioinformatic results indicate that the expression of Naa10p and IKKα is correlated with TGF‐β1/Smad and EMT‐related molecules. The Transwell migration, invasion, qRT‐PCR and Western blot assay indicated that Naa10p repressed OSCC cell migration, invasion and EMT, whereas IKKα promoted TGF‐β1–mediated OSCC cell migration, invasion and EMT. Mechanistically, Naa10p inhibited IKKα activation of Smad3 through the interaction with IKKα directly in OSCC cells after TGF‐β1 stimulation. Notably, knockdown of Naa10p reversed the IKKα‐induced change in the migration, invasion and EMT‐related molecules in OSCC cells after TGF‐β1 stimulation. These findings suggest that Naa10p interacted with IKKα mediates EMT in OSCC cells through TGF‐β1/Smad, a novel pathway for preventing OSCC.     

A novel multikinase inhibitor SKLB‐YTH‐60 ameliorates inflammation and fibrosis in bleomycin‐induced lung fibrosis mouse models

ObjectivesIdiopathic pulmonary fibrosis (IPF) is marked by the excessive accumulation of extracellular matrix, which participates in a variety of chronic diseases or injuries and seriously threatens human health. Due to the side effects of clinical drugs, there is still a need to develop novel and less toxic drugs to treat pulmonary fibrosis.Materials and MethodsSKLB‐YTH‐60 was developed through computer‐aided drug design, de novo synthesis and high‐throughput screening. We employed the bleomycin (BLM)‐induced lung fibrosis animal models and used TGF‐β₁ to induce the epithelial‐mesenchymal transition (EMT) of A549 cells in vitro. Meanwhile, the protein expression of collagen I and the α‐smooth muscle actin (α‐SMA), E‐cadherin, p‐FGFR1, p‐PLCγ, p‐Smad2/3 and p‐Erk1/2 was detected by western blot.ResultsYTH‐60 has obvious anti‐proliferative activity on fibroblasts and A549 cells. Moreover, YTH‐60 could impair the EMT of A549 cells and suppressed fibrosis by inhibiting FGFR and TGF‐β/Smad‐dependent pathways. Intraperitoneal administration of preventive YTH‐60 could significantly reduce the degree of fibrosis in mice and regulate the imbalance of the immune microenvironment. In addition, we observed that therapeutic YTH‐60 treatment attenuated fibrotic changes in mice during the period of fibrosis. Importantly, YTH‐60 has shown an acceptable oral bioavailability (F = 17.86%) and appropriate eliminated half‐life time (T _1/2 = 8.03 hours).ConclusionsTaken together, these preclinical evaluations suggested that YTH‐60 could be a promising drug candidate for treating IPF.     

MAIR‐II deficiency ameliorates cardiac remodelling post‐myocardial infarction by suppressing TLR9‐mediated macrophage activation

Macrophages are fundamental components of inflammation in post‐myocardial infarction (MI) and contribute to adverse cardiac remodelling and heart failure. However, the regulatory mechanisms in macrophage activation have not been fully elucidated. Previous studies showed that myeloid‐associated immunoglobulin–like receptor II (MAIR‐II) is involved in inflammatory responses in macrophages. However, its role in MI is unknown. Thus, this study aimed to determine a novel role and mechanism of MAIR‐II in MI. We first identified that MAIR‐II–positive myeloid cells were abundant from post‐MI days 3 to 5 in infarcted hearts of C57BL/6J (WT) mice induced by permanent left coronary artery ligation. Compared to WT, MAIR‐II–deficient (Cd300c2 ^−/−) mice had longer survival, ameliorated cardiac remodelling, improved cardiac function and smaller infarct sizes. Moreover, we detected lower pro‐inflammatory cytokine and fibrotic gene expressions in Cd300c2 ^−/−‐infarcted hearts. These mice also had less infiltrating pro‐inflammatory macrophages following MI. To elucidate a novel molecular mechanism of MAIR‐II, we considered macrophage activation by Toll‐like receptor (TLR) 9–mediated inflammation. In vitro, we observed that Cd300c2 ^−/− bone marrow–derived macrophages stimulated by a TLR9 agonist expressed less pro‐inflammatory cytokines compared to WT. In conclusion, MAIR‐II may enhance inflammation via TLR9‐mediated macrophage activation in MI, leading to adverse cardiac remodelling and poor prognosis.     

Adiponectin up‐regulates the decrease of myocardial autophagic flux induced by β1‐adrenergic receptor autoantibody partly dependent on AMPK

Cardiomyocytes autophagy is essential for maintaining cardiac function. Our previous studies have found that β₁‐adrenergic receptor autoantibody (β₁‐AA) induced the decreased myocardial autophagic flux, which resulted in cardiomyocyte death and cardiac dysfunction. And other studies demonstrated that β₁‐AA induced the decrease of AMPK phosphorylation, the key hub of autophagy pathway, while adiponectin up‐regulated autophagic flux mediated by AMPK. However, it is not clear whether adiponectin improves the inhibition of myocardial autophagic flux induced by β₁‐AA by up‐regulating the level of AMPK phosphorylation. In this study, it has been confirmed that β₁‐AA induced the decrease of AMPK phosphorylation level in both vivo and vitro. Moreover, pretreatment of cardiomyocytes with AMPK inhibitor Compound C could further reduce the autophagic flux induced by β₁‐AA. Adiponectin deficiency could aggravate the decrease of myocardial AMPK phosphorylation level, autophagic flux and cardiac function induced by β₁‐AA. Further, exogenous adiponectin could reverse the decline of AMPK phosphorylation level and autophagic flux induced by β₁‐AA and even reduce cardiomyocyte death. While pretreated with the Compound C, the adiponectin treatment did not improve the decreased autophagosome formation, but still improved the decreased autophagosome clearance induced by β₁‐AA in cardiomyocytes. This study is the first time to confirm that β₁‐AA could inhibit myocardial autophagic flux by down‐regulating AMPK phosphorylation level. Adiponectin could improve the inhibition of myocardial autophagic flux induced by β₁‐AA partly dependent on AMPK, so as to provide an experimental basis for the treatment of patients with β₁‐AA‐positive cardiac dysfunction.     

BNIP3 promotes HIF‐1α‐driven melanoma growth by curbing intracellular iron homeostasis

BNIP3 is a mitophagy receptor with context‐dependent roles in cancer, but whether and how it modulates melanoma growth in vivo remains unknown. Here, we found that elevated BNIP3 levels correlated with poorer melanoma patient’s survival and depletion of BNIP3 in B16‐F10 melanoma cells compromised tumor growth in vivo. BNIP3 depletion halted mitophagy and enforced a PHD2‐mediated downregulation of HIF‐1α and its glycolytic program both in vitro and in vivo. Mechanistically, we found that BNIP3‐deprived melanoma cells displayed increased intracellular iron levels caused by heightened NCOA4‐mediated ferritinophagy, which fostered PHD2‐mediated HIF‐1α destabilization. These effects were not phenocopied by ATG5 or NIX silencing. Restoring HIF‐1α levels in BNIP3‐depleted melanoma cells rescued their metabolic phenotype and tumor growth in vivo, but did not affect NCOA4 turnover, underscoring that these BNIP3 effects are not secondary to HIF‐1α. These results unravel an unexpected role of BNIP3 as upstream regulator of the pro‐tumorigenic HIF‐1α glycolytic program in melanoma cells.     

A disintegrin and metalloproteinase 8 induced epithelial‐mesenchymal transition to promote the invasion of colon cancer cells via TGF‐β/Smad2/3 signalling pathway

A disintegrin and metalloproteinase 8 (ADAM8) protein is a multi‐domain transmembrane glycoprotein which involves in extracellular matrix remodelling, cell adhesion, invasion and migration. ADAM8 and epithelial‐mesenchymal transition (EMT) play an important role in tumour invasion has been well established. However, the interaction between ADAM8 and EMT has remained unclear. The data of colon cancer patients obtained from TCGA (The Cancer Genome Atlas) and GTEx (Genotype‐Tissue Expression Project) were analysed by the bioinformatics research method. The expression of ADAM8 in colon cancer cells was up‐regulated and down‐regulated by transfecting with the expression plasmid and small interfering RNA, respectively. Transwell invasion assay, immunohistochemistry, immunocytochemistry, Western blotting and qRT‐PCR were utilized to study the effect of ADAM8 on colon cancer cell''s EMT and its related mechanisms. Analysis of TCGA and GTEx data revealed that ADAM8 was linked to poor overall survival in colon cancer patients. Besides, ADAM8 was correlated with multiple EMT biomarkers (E‐cadherin, N‐cadherin, Vimentin, Snail2 and ZEB2). In vitro, we also proved that the up‐regulation of ADAM8 could promote EMT effect and enhance the invasive ability of colon cancer cells. On the contrary, the down‐regulation of ADAM8 in colon cancer cells attenuated these effects above. Further studies suggested that ADAM8 modulated EMT on colon cancer cells through TGF‐β/Smad2/3 signalling pathway. Our research suggested that ADAM8 could be a potential biomarker for the prognosis of colon cancer and induced EMT to promote the invasion of colon cancer cells via activating TGF‐β/Smad2/3 signalling pathway.     

LncRNA ARAP1‐AS2 promotes high glucose‐induced human proximal tubular cell injury via persistent transactivation of the EGFR by interacting with ARAP1

The persistent transactivation of epidermal growth factor receptor (EGFR) causes subsequent activation of the TGF‐β/Smad3 pathway, which is closely associated with fibrosis and cell proliferation in diabetic nephropathy (DN), but the exact mechanism of persistent EGFR transactivation in DN remains unclear. ARAP1, a susceptibility gene for type 2 diabetes, can regulate the endocytosis and ubiquitination of membrane receptors, but the effect of ARAP1 and its natural antisense long non‐coding RNA (lncRNA), ARAP1‐AS2, on the ubiquitination of EGFR in DN is not clear. In this study, we verified that the expression of ARAP1 and ARAP1‐AS2 was significantly up‐regulated in high glucose‐induced human proximal tubular epithelial cells (HK‐2 cells). Moreover, we found that overexpression or knockdown of ARAP1‐AS2 could regulate fibrosis and HK‐2 cell proliferation through EGFR/TGF‐β/Smad3 signalling. RNA pulldown assays revealed that ARAP1‐AS2 directly interacts with ARAP1. Coimmunoprecipitation, dual‐immunofluorescence and ubiquitination assays showed that ARAP1 may maintain persistent EGFR activation by reducing EGFR ubiquitination through competing with Cbl for CIN85 binding. Taken together, our results suggest that the lncRNA ARAP1‐AS2 may promote high glucose‐induced proximal tubular cell injury via persistent EGFR/TGF‐β/Smad3 pathway activation by interacting with ARAP1.     

Gut inflammation triggers C/EBPβ/δ‐secretase‐dependent gut‐to‐brain propagation of Aβ and Tau fibrils in Alzheimer’s disease

Inflammation plays an important role in the pathogenesis of Alzheimer''s disease (AD). Some evidence suggests that misfolded protein aggregates found in AD brains may have originated from the gut, but the mechanism underlying this phenomenon is not fully understood. C/EBPβ/δ‐secretase signaling in the colon was investigated in a 3xTg AD mouse model in an age‐dependent manner. We applied chronic administration of 1% dextran sodium sulfate (DSS) to trigger gut leakage or colonic injection of Aβ or Tau fibrils or AD patient brain lysates in 3xTg mice and combined it with excision/cutting of the gut–brain connecting vagus nerve (vagotomy), in order to explore the role of the gut–brain axis in the development of AD‐like pathologies and to monitor C/EBPβ/δ‐secretase signaling under those conditions. We found that C/EBPβ/δ‐secretase signaling is temporally activated in the gut of AD patients and 3xTg mice, initiating formation of Aβ and Tau fibrils that spread to the brain. DSS treatment promotes gut leakage and facilitates AD‐like pathologies in both the gut and the brain of 3xTg mice in a C/EBPβ/δ‐secretase‐dependent manner. Vagotomy selectively blunts this signaling, attenuates Aβ and Tau pathologies, and restores learning and memory. Aβ or Tau fibrils or AD patient brain lysates injected into the colon propagate from the gut into the brain via the vagus nerve, triggering AD pathology and cognitive dysfunction. The results indicate that inflammation activates C/EBPβ/δ‐secretase and initiates AD‐associated pathologies in the gut, which are subsequently transmitted to the brain via the vagus nerve.     

METTL3 promotes IL‐1β–induced degeneration of endplate chondrocytes by driving m6A‐dependent maturation of miR‐126‐5p

METTL3 is an important regulatory molecule in the process of RNA biosynthesis. It mainly regulates mRNA translation, alternative splicing and microRNA maturation by mediating m6A‐dependent methylation. Interleukin 1β (IL‐1β) is an important inducer of cartilage degeneration that can induce an inflammatory cascade reaction in chondrocytes and inhibit the normal biological function of cells. However, it is unclear whether IL‐1β is related to METTL3 expression or plays a regulatory role in endplate cartilage degeneration. In this study, we found that the expression level of METTL3 and methylation level of m6A in human endplate cartilage with different degrees of degeneration were significantly different, indicating that the methylation modification of m6A mediated by METTL3 was closely related to the degeneration of human endplate cartilage. Next, through a series of functional experiments, we found that miR‐126‐5p can play a significant role in IL‐1β–induced degeneration of endplate chondrocytes. Moreover, we found that miR‐126‐5p can inhibit the PI3K/Akt signalling pathway by targeting PIK3R2 gene, leading to the disorder of cell vitality and functional metabolism. To further determine whether METTL3 could regulate miR‐126‐5p maturation, we first confirmed that METTL3 can bind the key protein underlying pri‐miRNA processing, DGCR8. Additionally, when METTL3 expression was inhibited, the miR‐126‐5p maturation process was blocked. Therefore, we hypothesized that METTL3 can promote cleavage of pri‐miR‐126‐5p and form mature miR‐126‐5p by combining with DGCR8.