Ovarian cancer (OvCa) preferentially metastasizes in association with mesothelial cell-lined surfaces. We sought to determine if mesothelial cells are required for OvCa metastasis and detect alterations in mesothelial cell gene expression and cytokine secretion upon interaction with OvCa cells. Using omental samples from patients with high-grade serous OvCa and mouse models with Wt1-driven GFP-expressing mesothelial cells, we validated the intratumoral localization of mesothelial cells during human and mouse OvCa omental metastasis. Removing mesothelial cells ex vivo from human and mouse omenta or in vivo using diphtheria toxin mediated ablation in Msln-Cre mice, significantly inhibited OvCa cell adhesion and colonization. Human ascites induced angiopoietin-like 4 (ANGPTL4) and stanniocalcin 1 (STC1) expression and secretion by mesothelial cells. Inhibition of STC1 or ANGPTL4 via RNAi, obstructed OvCa cell-induced mesothelial cell to mesenchymal transition while inhibition of ANGPTL4 alone obstructed OvCa cell-induced mesothelial cell migration and glycolysis. Inhibition of mesothelial cell ANGPTL4 secretion via RNAi prevented mesothelial cell induced monocyte migration, endothelial cell vessel formation and OvCa cell adhesion, migration, and proliferation. In contrast, inhibition of mesothelial cell STC1 secretion via RNAi prevented mesothelial cell induced endothelial cell vessel formation and OvCa cell adhesion, migration, proliferation, and invasion. Additionally, blocking ANPTL4 function with antibodies reduced the ex vivo colonization of three different OvCa cell lines on human omental tissue explants and in vivo colonization of ID8p53-/-Brca2-/- cells on mouse omenta. These findings indicate that mesothelial cells are important to the initial stages of OvCa metastasis, and that the crosstalk between mesothelial cells and the tumor microenvironment, promotes OvCa metastasis through the secretion of ANGPTL4.
Preety Bajwa, Kasjusz Kordylewicz, Agnes Bilecz, Ricardo R. Lastra, Kristen Wroblewski, Yuval Rinkevich, Ernst Lengyel, Hilary A. Kenny
Mesenchymal stem cells (MSCs) possess strong immunoregulatory functions, one aspect of which is recruiting monocytes from peripheral vessels to local tissue by secreting MCP1. However, the regulatory mechanisms of MCP1 secretion in MSCs are still unclear. Recently, N6-methyladenosine (m6A) modification was reported to be involved in the functional regulation of MSCs. In this study, we demonstrated that methyltransferase-like 16 (METTL16) negatively regulated MCP1 expression in MSCs through m6A modification. Specifically, the expression of METTL16 in MSCs decreased gradually and was negatively correlated with the expression of MCP1 after coculture with monocytes. Knocking down METTL16 markedly enhanced MCP1 expression and the ability to recruit monocytes. Mechanistically, knocking down METTL16 decreased MCP1 mRNA degradation, which was mediated by the m6A reader YTH N6-methyladenosine RNA binding protein 2 (YTHDF2). We further revealed that YTHDF2 specifically recognized m6A sites on MCP1 mRNA in the CDS region and thus negatively regulated MCP1 expression. Moreover, an in vivo assay showed that MSCs transfected with METTL16 siRNA showed a stronger ability to recruit monocytes. These findings reveal a potential mechanism by which the m6A methylase METTL16 regulates MCP1 expression through YTHDF2-mediated mRNA degradation and suggest a potential strategy to manipulate MCP1 expression in MSCs.
Zhaoqiang Zhang, Zhongyu Xie, Jiajie Lin, Zehang Sun, Zhikun Li, Wenhui Yu, Yipeng Zeng, Guiwen Ye, Jinteng Li, Feng Ye, Zepeng Su, Yunshu Che, Peitao Xu, Chenying Zeng, Peng Wang, Yanfeng Wu, Huiyong Shen
As a hallmark for inflammatory bowel disease (IBD), elevated intestinal epithelial cell (IEC) death compromises the gut barrier, activating inflammatory response and triggering more IEC death. However, the precise intracellular machinery that prevents IEC death and break this vicious feedback remains largely unknown. Here, we report that Gab1 expression is decreased in patients with IBD and inversely correlated with IBD severity. Gab1 deficiency in intestinal epithelial cells accounts for the exacerbated colitis induced by dextran sodium sulfate (DSS) owing to sensitizing IECs to RIPK3-mediated necroptosis, which irreversibly disrupted homeostasis of the epithelial barrier and promoted intestinal inflammation. Mechanistically, Gab1 negatively regulates necroptosis signaling through inhibiting the formation of RIPK1/RIPK3 complex in response to TNF-α. Importantly, administration of RIPK3 inhibitor reveals a curative effect in epithelial Gab1-deficient mice. Further analysis indicates mice with Gab1 deletion are prone to inflammation associated colorectal tumorigenesis. Collectively, our study defines a protective role for Gab1 in colitis and colitis-driven colorectal cancer through negatively regulating RIPK3-dependent necroptosis, in which may serve as an important target to fine-tune necroptosis and intestinal inflammation-related disease.
Jiaqi Xu, Shihao Li, Wei Jin, Hui Zhou, Tingting Zhong, Xiaoqing Cheng, Yujuan Fu, Peng Xiao, Hongqiang Cheng, Di Wang, Yuehai Ke, Zhinong Jiang, Xue Zhang
Glioblastoma is the most malignant primary brain tumor for which the prognosis remains dismal even with aggressive surgical, medical, and radiation therapies. Glioblastoma stem cells (GSCs) promote therapeutic resistance and cellular heterogeneity due to their self-renewal properties and capacity for plasticity. To understand the molecular processes essential for maintaining GSCs, we performed an integrative analysis comparing active enhancer landscapes, transcriptional profiles, and functional genomics profiles of GSCs and non-neoplastic neural stem cells (NSCs). We identified sorting nexin 10 (SNX10), an endosomal protein sorting factor, as selectively expressed in GSCs compared to NSCs and essential for GSC survival. Targeting SNX10 impaired GSC viability and proliferation, induced apoptosis, and reduced self-renewal capacity. Mechanistically, GSCs utilized endosomal protein sorting to promote platelet-derived growth factor receptor β (PDGFRβ) proliferative and stem cell signaling pathways through post-transcriptional regulation of the PDGFR tyrosine kinase. Targeting SNX10 expression extended survival of orthotopic xenograft-bearing mice, and high SNX10 expression correlated with poor glioblastoma patient prognosis, suggesting its potential clinical importance. Thus, our study reveals an essential connection between endosomal protein sorting and oncogenic receptor tyrosine kinase signaling and suggests that targeting endosomal sorting may represent a promising therapeutic approach for glioblastoma treatment.
Ryan C. Gimple, Guoxin Zhang, Shuai Wang, Tengfei Huang, Jina Lee, Suchet Taori, Deguan Lv, Deobrat Dixit, Matthew E. Halbert, Andrew R. Morton, Reilly L. Kidwell, Zhen Dong, Briana C. Prager, Leo Kim, Zhixin Qiu, Linjie Zhao, Qi Xie, Qiulian Wu, Sameer Agnihotri, Jeremy N. Rich
Arrhythmogenic cardiomyopathy (AC) is a familial heart disease partly caused by impaired desmosome turnover. Thus, stabilization of desmosome integrity may provide potential new treatment options. Desmosomes, apart from cellular cohesion, provide the structural framework of a signaling hub. Here, we investigated the role of the epidermal growth factor receptor (EGFR) in cardiomyocyte cohesion. We inhibited EGFR under physiological and pathophysiological conditions using the murine plakoglobin knockout AC model, in which EGFR was upregulated. EGFR inhibition enhanced cardiomyocyte cohesion. Immunoprecipitation showed an interaction of EGFR and desmoglein 2 (DSG2). Immunostaining and AFM revealed enhanced DSG2 localization and binding at cell borders upon EGFR inhibition. Enhanced area composita length and desmosome assembly were observed upon EGFR inhibition, confirmed by enhanced DSG2 and desmoplakin (DP) recruitment to cell borders. PamGene Kinase assay performed in HL-1 cells treated with Erlotinib, an EGFR inhibitor, revealed upregulation of RhoA associated protein kinase (ROCK). Erlotinib-mediated desmosome assembly and cardiomyocyte cohesion were abolished upon ROCK inhibition. Thus, inhibiting EGFR, thereby stabilizing desmosome integrity via ROCK, might provide new treatment options for AC.
Maria Shoykhet, Orsela Dervishi, Philipp Menauer, Matthias Hiermaier, Sina Moztarzadeh, Colin Osterloh, Ralf J. Ludwig, Tatjana Williams, Brenda Gerull, Stefan Kaab, Sebastian Clauss, Dominik Schüttler, Jens Waschke, Sunil Yeruva
The transcription factor c-Maf has been widely studied and has been reported to play a critical role in embryonic kidney development; however, the postnatal functions of c-Maf in adult kidneys remain unknown as c-Maf null C57BL/6J mice exhibit embryonic lethality. In this study, we investigated the role of c-Maf in adult mouse kidneys by comparing the phenotypes of tamoxifen (TAM)-inducible c-Maf knockout mice (c-Maf flox/flox; CAG-Cre-ERTM mice named “c-Maf ΔTAM”) with c-Maf flox/flox control mice10 days after TAM injection (TAM(10d)). In addition, we examined the effects of c-Maf deletion on diabetic conditions by injecting the mice with streptozotocin (STZ) four weeks before TAM injection. c-Maf ΔTAM mice displayed primary glycosuria caused by Sglt2 and Glut2 downregulation in the kidneys without diabetes, as well as morphological changes and life-threatening injuries in the kidneys on TAM(10d). Under diabetic conditions, c-Maf deletion promoted recovery from hyperglycemia and suppressed albuminuria and diabetic nephropathy by causing similar effects to Sglt2 knockout and SGLT2 inhibitors. In addition to demonstrating the unique gene regulation of c-Maf, these findings highlight the renoprotective effects of c-Maf deficiency under diabetic conditions and suggest that c-Maf could be a novel therapeutic target gene for treating diabetic nephropathy.
Mitsunori Fujino, Naoki Morito, Takuto Hayashi, Masami Ojima, Shun Ishibashi, Akihiro Kuno, Seizo Koshiba, Kunihiro Yamagata, Satoru Takahashi
Low CC16 plasma levels are linked to accelerated lung function decline in COPD patients. Cigarette smoke (CS)-exposed Cc16-/- mice have exaggerated COPD-like disease associated with increased NF-kB activation in their lungs. It is unclear whether CC16 augmentation can reverse exaggerated COPD in CS-exposed Cc16-/- mice and whether increased NF-kB activation contributes to the exaggerated COPD in CS-exposed Cc16-/- lungs. CS-exposed WT and Cc16-/- mice were treated with recombinant human CC16 protein solution (rhCC16) or a NF-kB inhibitor (IMD0354) versus vehicle beginning at the mid-point of the exposures. COPD-like disease and NF-kB activation were measured in the lungs. RhCC16 limited the progression of emphysema, small airway fibrosis, and chronic-bronchitis-like disease in WT and Cc16-/- mice partly by reducing pulmonary inflammation (reducing myeloid leukocytes and/or increasing regulatory T and/or B cells) and alveolar septal cell apoptosis, reducing NF-kB activation in CS-exposed Cc16-/- lungs, and rescuing the reduced Foxj1 expression in CS-exposed Cc16-/- lungs. IMD0354 treatment reduced exaggerated lung inflammation and rescued the reduced Foxj1 expression in CS-exposed Cc16-/- mice. rhCC16 treatment reduced NF-kB activation in luciferase reporter A549 cells. Thus, rhCC16 treatment limits COPD progression in CS-exposed Cc16-/- mice partly by inhibiting NF-kB activation and represents a novel therapeutic approach for COPD.
Joselyn Rojas-Quintero, Maria E. Laucho-Contreras, Xiaoyun Wang, Quynh-Anh Fucci, Patrick R. Burkett, Se-Jin Kim, Duo Zhang, Yohannes Tesfaigzi, Yuhong Li, Abhiram R. Bhashyam, Li Zhang, Haider Khamas, Bartolome Celli, Aprile L. Pilon, Francesca Polverino, Caroline A. Owen
The molecular clock machinery regulates several homeostatic rhythms, including glucose metabolism. We previously demonstrated that Roux-en Y Gastric Bypass (RYGB) has a weight-independent effect on glucose homeostasis, and transiently reduces food intake. In this study we investigate the effects of RYGB on diurnal eating behavior as well as its effects on the molecular clock, and its requirement for the metabolic effects of this bariatric procedure in obese mice. We find that RYGB reverses the high fat diet-induced disruption in diurnal eating pattern during the early post-surgery phase of food reduction. “Dark-cycle” pair-feeding experiments improved glucose tolerance to the level of bypass-operated animals during the physiologic “fasting” phase (Zeitgeber ZT2), but not the “feeding” phase (ZT14). Using a clock gene reporter mouse model (mPer2Luc), we reveal that RYGB induces a liver-specific phase shift in peripheral clock oscillation with no changes to the central clock activity within the suprachiasmatic nucleus (SCN). In addition, we show that weight loss effects are attenuated in obese ClockΔ19 mutant mice post-RYGB that also fail to improve glucose metabolism after surgery, specifically hepatic glucose production. We conclude that RYGB reprograms the peripheral clock within the liver early after surgery to alter diurnal eating behavior and regulate hepatic glucose flux.
Yuanchao Ye, Marwa Abu El Haija, Reine Obeid, Hussein Herz, Liping Tian, Benjamin Linden, Yi Chu, Deng Fu Guo, Daniel C. Levine, Jonathan Cedernaes, Kamal Rahmouni, Joseph Bass, Mohamad Mokadem
The pronounced choleretic properties of norursodeoxycholic acid (norUDCA) to induce bicarbonate-rich bile secretion have been attributed to its ability to undergo cholehepatic shunting. The goal of this study was to identify the mechanisms underlying the choleretic actions of norUDCA and role of the bile acid transporters. Here, we show that the apical sodium-dependent bile acid transporter (ASBT), Organic solute transporter-alpha (OSTα), and Organic anion transporting polypeptide 1a/1b (OATP1a/1b) transporters are dispensable for the norUDCA-stimulation of bile flow and biliary bicarbonate secretion. Chloride channels in biliary epithelial cells provide the driving force for biliary secretion. norUDCA potently stimulated chloride currents in mouse large cholangiocytes, which was blocked by siRNA silencing and pharmacological inhibition of the calcium-activated chloride channel transmembrane member 16A (TMEM16A), but unaffected by ASBT inhibition. In agreement, blocking intestinal bile acid reabsorption by co-administration of an ASBT inhibitor or bile acid sequestrant did not impact norUDCA stimulation of bile flow in wildtype mice. The results indicate that these major bile acid transporters are not directly involved in the absorption, cholehepatic shunting, or choleretic actions of norUDCA. Additionally, the findings support further investigation of the therapeutic synergy between norUDCA and ASBT inhibitors or bile acid sequestrants for cholestatic liver disease.
Jennifer K. Truong, Jianing Li, Qin Li, Kimberly Pachura, Anuradha Rao, Sanjeev Gumber, Claudia D. Fuchs, Andrew P. Feranchak, Saul J. Karpen, Michael Trauner, Paul A. Dawson
Cardiac fibrosis is associated with an adverse prognosis in cardiovascular disease, which results in a decreased cardiac compliance and ultimately heart failure. Recent studies have identified the role of long non-coding RNA (lncRNA) in cardiac fibrosis. However, the functions of many lncRNAs in cardiac fibrosis remain to be characterized. Through a whole-transcriptome sequencing and bioinformatics analysis on a mouse model of pressure overload-induced cardiac fibrosis, we screened a key lncRNA termed thrombospondin 1 antisense 1 (THBS1-AS1), which was positively associated with cardiac fibrosis. In vitro functional studies demonstrated that the silencing of THBS1-AS1 ameliorated TGF-β1 effects on cardiac fibroblasts (CFs) activation and the overexpression of THBS1-AS1 displayed the opposite effect. A mechanistic study revealed that THBS1-AS1 could sponge miR-221/222 to regulate the expression of TGFBR1. Moreover, under TGF‐β1 stimulation, the forced expression of miR-221/222 or the knockdown TGFBR1 significantly reversed the THBS1-AS1 overexpression induced further cardiac fibroblast activation. In vivo, specific knockdown of THBS1-AS1 in activated cardiac fibroblasts significantly alleviated transverse aorta constriction (TAC)-induced cardiac fibrosis in mice. Finally, we demonstrated that the human THBS1-AS1 can also affect the activation of cardiac fibroblasts by regulating TGFBR1. In conclusion, this study reveals that lncRNA THBS1-AS1 is a novel regulator of cardiac fibrosis and may serve as a potential target for the treatment of cardiac fibrosis.
Junteng Zhou, Geer Tian, Yue Quan, Qihang Kong, Fangyang Huang, Junli Li, Wenchao Wu, Yong Tang, Zhichao Zhou, Xiaojing Liu
No posts were found with this tag.