BrdU Assay Research Articles

Vitamin D receptor and its antiproliferative effect in human pulmonary arterial hypertension

Vitamin D (vitD) deficiency is frequently observed in patients with pulmonary arterial hypertension (PAH) and, in these patients, low levels of vitD correlate with worse prognosis. The aim of this study was to examine the expression and the antiproliferative role of vitD receptor (VDR) and its signalling pathway in the human pulmonary vasculature. VDR presence and expression was analyzed in lungs, pulmonary artery smooth muscle cells (PASMC) and endothelial cells (PAEC) from controls and PAH-patients. VDR expression and VDR-target genes were examined in PASMC treated with calcitriol. The antiproliferative effect of 48 h-calcitriol was studied in PASMC by MTT and BrdU assays. VDR is expressed in PASMC. It is downregulated in lungs and in PASMC, but not in PAEC, from PAH-patients compared to non-hypertensive controls. Calcitriol strongly upregulated VDR expression in PASMC and the VDR target genes KCNK3 (encoding TASK1), BIRC5 (encoding survivin) and BMP4. Calcitriol produced an antiproliferative effect which was diminished by silencing or by pharmacological inhibition of survivin or BMPR2, but not of TASK1. In conclusion, the expression of VDR is low in PAH-patients and can be rescued by calcitriol. VDR exerts an antiproliferative effect in PASMC by modulating survivin and the BMP signalling pathway.

Broussoflavonol F exhibited anti-proliferative and anti-angiogenesis effects in colon cancer via modulation of the HER2-RAS-MEK-ERK pathway

BackgroundA prenylated flavonoid, broussoflavonol F (BFF), was isolated from Macaranga genus with cytotoxicities against various cancer cells, though its underlying mechanisms have not been fully elucidated. HypothesisThis study aimed to investigate the anti-tumor and anti-angiogenesis activities of BFF and its underlying mechanisms in colon cancer. MethodIn the in vitro study, the cytotoxic effects of BFF in human colon cancer HCT-116 and LoVo cells were examined using MTT assay, BrdU assay and colony formation assay. The anti-proliferative effects of BFF in these cells were assessed via cell apoptosis and cell cycle analysis using flow cytometry. The anti-angiogenesis effects of BFF in human endothelial HEMC-1 cells were also detected using scratch wound healing assay and tube formation assay. While the in vivo effects of BFF in colon cancer were further examined in zebrafish embryos and HCT116 tumor-bearing mice. The underlying mechanisms of BFF were predicted using network pharmacology analysis, and Western blotting was performed to validate both in vitro and in vivo results. ResultsBFF exhibited cytotoxicities on 5 colon cancer cell lines, as well as anti-proliferative activities via inducing apoptosis and cell cycle arrest at the G0/G1 phase in HCT116 and LoVo cells. BFF at 1.25-5 µM also suppressed cell proliferation in these two colon cancer cell lines by downregulating HER2, RAS, p-BRAF, p-MEK and p-Erk protein expressions. In addition, BFF at 2.5-5 µM could significantly decrease the length of subintestinal vessels of zebrafish embryos through decreasing mRNA expressions of NRP1a, PDGFba, PDGFRb, KDR, FLT1 and VEGRaa. Besides, BFF exhibited anti-angiogenesis activity via inhibiting cell proliferation, motility and tube formation in HMEC-1 cells. Furthermore, intraperitoneal administration of BFF (10 mg/kg) suppressed tumor growth and decreased the expression of tumor proliferation marker Ki-67 and angiogenesis marker CD31 in the tumor tissues in HCT116 tumor-bearing mice. BFF treatment could also significantly decrease expressions of RAS, p-BRAF, p-MEK and p-Erk in the tumor section, which are consistent with the in vitro results. ConclusionsThis study revealed the anti-tumor and anti-angiogenesis effects of BFF in colon cancer. This is the first report of the in vitro and in vivo anti-proliferative activity of BFF in colon cancer through regulating the HER2-RAS-MEK-ERK pathway. These findings further support the research development of BFF as an anti-cancer agent in colon cancer.

Investigating the role of an orphan nuclear receptor NR4A1 in atrial fibrillation

Abstract Introduction Atrial fibrosis is a major remodelling process in atrial fibrillation (AF). The lack of clinically effective drug targets, due to insufficient understanding of the mechanisms of cardiac fibrosis, hampers the treatment of AF. Orphan nuclear receptor subfamily 4 group A member 1 (NR4A1) is linked to fibrotic disease in multiple organs, however, its role in cardiac fibrosis and AF is yet to be demonstrated. Recent transcriptomic profiling revealed that NR4A1 expression is downregulated in human atrial cardiac fibroblasts (ACFs) in the presence of persistent AF. However, its mechanistic role in atrial fibrogenesis and AF is unknown. Purpose To investigate the expression profile and function of NR4A1 in human ACFs and provide insights into the role of NR4A1 in the context of persistent AF. Methods Human ACFs were isolated (enzymatic digestion) from right and left atrial appendages of 24 patients with persistent AF and controls in sinus rhythm (SR), who had elective heart surgery. NR4A1 knockdown in ACFs was achieved using NR4A1-siRNA. Gene and protein expression were determined by qPCR and western blot respectively, while BrdU assay and scratch assay were used to evaluate cell proliferation and migration. Atrial fibroblasts subpopulations were identified by single-nucleus RNA-sequencing. Subcellular localisation of NR4A1 was assessed by immunostaining, analysed by ImageJ. Results Validation of RNA-sequencing data confirmed a reduction of NR4A1 gene expression in human ACFs in persistent AF by 25% (p=0.029, Fig. 1A) and the NR4A1 predominant abundance in one of three identified subclusters of human ACFs (NR4A1+NAMPT+). The siRNA-mediated knockdown of NR4A1 in ACFs suppressed gene and protein expression of important component of extracellular matrix collagen-1 (Fig. 1B and Fig. 1C) and fibronectin protein (but not mRNA). The NR4A1-deficient cells also had decreased alpha-smooth muscle actin (αSMA) protein and gene expression (Fig. 1D and Fig. 1E), reduced periostin gene expression in the absence of changes in its protein. Furthermore, the NR4A1-deficiency reduced proliferation (by 18%, p=0.005, Fig. 1F) and accelerated migration (p=0.019, Fig. 1G) of human ACFs. These effects were independent of TGF-β1 stimulation, unlike reported in rat neonatal cardiac and dermal fibroblasts. Despite decreased NR4A1 gene expression, patients with AF had doubled NR4A1 protein levels compared to SR-ACFs (p=0.049, Fig. 2A). This was associated with abnormal 1.8-fold increase in the receptor subcellular localisation (p=0.032, Fig. 2B and Fig. 2C), as opposed to the physiological nuclear localisation observed in ACFs in the absence of AF. Conclusion While under physiological conditions, NR4A1 potently activates profibrotic processes in human ACFs, persistent AF patients have increased but abnormally distributed NR4A1 protein in atrial fibroblasts, whose consequences are yet to be determined in order to develop new therapies for AF.Figure 1Figure 2

TRAF4 promotes lung cancer development by activating tyrosine kinase of EGFR

Objective: To explore the role of tumor necrosis factor receptor-associated factor 4 (TRAF4) in promoting the abnormal activation of epidermal growth factor receptor (EGFR) and its effect on lung cancer cell proliferation, migration and invasion. Methods: Tumor tissues from patients who underwent lung adenocarcinoma resection at The First Affiliated Hospital of Second Military Medical University, from January 2015 to May 2017 were collected, and the expressions of TRAF4 and Ki-67 in lung cancer tissues were detected by immunohistochemistry, the mRNA levels of Cyclin D and Vimentin were detected by real-time fluorescence quantitative PCR (qRT-PCR). The effect of TRAF4 on the tumor growth ability of lung cancer A549 cells was investigated by the xenograft model, the effect of TRAF4 or EGFR on the tumor proliferation ability was detected by using cell counting kit 8 (CCK8) and BrdU assay, and the migration and invasion abilities of tumor cells were detected by Transwell assay. Different structural domain deletion expression vectors of TRAF4 and EGFR were constructed to transfect cells, and the interaction mode of TRAF4 and EGFR was investigated by immunoprecipitation assay. Results: The expression of TRAF4 in non-small cell lung cancer (NSCLC) tissues was positively correlated with the expressions of Ki-67, cyclin D, and vimentin (r2: 0.438, 0.695, and 0.736, respectively, all P＜0.01). Immunohistochemical assay of tumor tissues from NSCLC patients showed that tissues with high expression of TRAF4 were also high in Ki-67. Patients with high TRAF4 expression (TRAF4 positivity >30%) had a shorter progression-free survival (PFS) time than that of patients with low TRAF4 expression (TRAF4 positivity ≤30%) (median PFS of 12 and 19 months, respectively; P=0.034). Traf4-/- cells had a weakened proliferative capacity than traf4+/+ cells and formed tumors with smaller size (P＜0.05). The expression level of Ki-67 in the tumor tissues formed by traf4-/- cells [(45.6±8.7)%] was lower than that in the tumor tissues formed by traf4+/+ cells [(62.3±10.3)%, P=0.015], the mRNA levels of cyclin D (1.01±0.15) and vimentin (1.01±0.12) in the traf4-/- cells were lower than those of the traf4+/+ cells (3.41±0.32 and 3.12±0.18, respectively, both P＜0.05).The western blot results showed that, with the elevated intracellular expression level of TRAF4, phosphorylation level of EGFR was significantly increased in both wild-type EGFR and activation mutant EGFR-expression cells. The capacities of proliferation, migration and invasion of A549 cells was weakened after EGFR knockdown (all P＜0.01). Immunoprecipitation experiments showed that TRAF4 binds to the peptide segment of the near-membrane region of EGFR through the TRAF structural domain, and the mutual binding between EGFR molecules was enhanced under TRAF4 overexpression conditions. Increasing TRAF4 expression promoted EGFR molecular phosphorylation and activation of downstream signaling. Conclusions: TRAF4 expression is elevated in NSCLC tissues and tumor cells, which promotes tumor proliferation, migration and invasion. TRAF4 directly binds to EGFR molecules, enhances its own phosphorylation and activates the downstream signaling pathway by promoting the interaction between EGFR molecules.

CD74+ fibroblasts proliferate upon mechanical stretching to promote angiogenesis in keloids.

The healing of human skin wounds is susceptible to perturbation caused by excessive mechanical stretching, resulting in enlarged scars, hypertrophic scars, or even keloids in predisposed individuals. Keloids are fibro-proliferative scar tissues that extend beyond the initial wound boundary, consisting of the actively progressing periphery and the quiescent center. The stretch-associated outgrowth and enhanced angiogenesis are two features of the periphery of keloids. However, which cell population is responsible for transducing the mechanical stimulation to the progression of keloids remains unclear. Herein, through integrative analysis of single-cell RNA sequencing of keloids, we identified CD74+ fibroblasts, a previously unappreciated subset of fibroblasts with pro-angiogenic and stretch-induced proliferative capacities, as a key player in stretch-induced progression of keloids. Immunostaining of keloid cryosections depicted a predominant distribution of CD74+ fibroblasts in the periphery, interacting with the vasculature. Invitro tube formation assays on purified CD74+ fibroblasts ascertained their pro-angiogenic function. BrdU assays revealed that these cells proliferate upon stretching, through PIEZO1-mediated calcium influx and the downstream ERK and AKT signaling. Collectively, our findings propose a model wherein CD74+ fibroblasts serve as pivotal drivers of stretch-induced keloid progression, fueled by their proliferative and pro-angiogenic activities. Targeting the attributes of CD74+ fibroblasts holds promise as a therapeutic strategy for the management of keloids.

In vitro cytotoxicity assessment of ruxolitinib on oligodendrocyte precursor cell and neural stem/progenitor cell populations

JAK-STAT signaling cascade has emerged as an ideal target for the treatment of myeloproliferative diseases, autoimmune diseases, and neurological disorders. Ruxolitinib (Rux), is an orally bioavailable, potent and selective Janus-associated kinase (JAK) inhibitor, proven to be effective to target activated JAK-STAT pathway in the diseases previously described. Unfortunately, limited studies have investigated the potential cytotoxic profile of Rux on other cell populations within the heterogenous CNS microenvironment. Two stem and progenitor cell populations, namely the oligodendrocyte precursor cells (OPCs) and neural stem/progenitor cells (NSPCs), are important for long-term maintenance and post-injury recovery response of the CNS. In light of the limited evidence, this study sought to investigate further the effect of Rux on proliferating and differentiating OPCs and NSPCs populations. In the present study, cultured rat OPCs and NSPCs were treated with various concentrations of Rux, ranging from 2 μM to 20 μM. The effect of Rux on proliferating OPCs (PDGF-R-α+) and proliferating NSPCs (nestin+) was assessed via a 3-day Rux treatment, whereas its effect on differentiating OPCs (MBP+/PDGF-R-α+) and differentiating NSPCs (neurofilament+) was assessed after a 7-day treatment. Cytotoxicity of Rux was also assessed on OPC populations by examining its influence on cell death and DNA synthesis via YO-PRO-1/PI dual-staining and BrdU assay, respectively. The results suggest that Rux at a dosage above 10 μM reduces the number proliferating OPCs, likely via the induction of apoptosis. On the other hand, Rux treatment from 2.5 μM to 20 μM significantly reduces the number of differentiating OPCs by inducing necrosis. Meanwhile, Rux treatment has no observable untoward impact on NSPC cultures within the dosage range tested. Taken together, OPCs appears to be more vulnerable to the dosage effect of Rux, whereas NSPCs are not significantly impacted by Rux, suggesting a differential mechanism of actions of Rux on the cell types.

Glycine Receptor Beta Subunit (GlyR-β) Promotes Potential Angiogenesis and Neurological Regeneration during Early-Stage Recovery after Cerebral Ischemia Stroke/Reperfusion in Mice.

Ischemic stroke is mainly caused by cerebral artery thrombosis. This study investigated the role of glycine receptor beta subunit (GlyR-β) in the recovery from cerebral ischemia stroke/reperfusion. The oxygen glucose deprivation and recovery (OGD/R) bEnd3 cell model and the middle cerebral artery occlusion/reperfusion (MCAO/R) mouse model were used in this study. Expression of both the GlyR-β gene and vascular endothelial growth factor (Vegf), cell proliferation, and tube formation ability was decreased in bEnd3 cells after OGD/R, and was reversed by overexpression of GlyR-β. Neurological function, asindicated by Zea Longa scores, area of cerebral ischemia, and pathological changes were increased in mice after MCAO/R, and were ameliorated by overexpression of the glycine receptor beta (Glrb) gene at 24 h and 7 d after MCAO/R. Expression of GlyR-β and Gap-43 was decreased, and the expression of CD34, Vegf, and Bdnf, and cell growth as determined by a bromodeoxyuridine (BrdU) assay, increased in the affected brain tissue of MCAO/R mice in a time-dependent manner. GlyR-β overexpression resulted in enhanced expression of CD34, Vegf, Growth association protein 43 (Gap-43), and brain-derived neurotrophic factor (Bdnf) and cell growth in affected brain tissue of MCAO/R mice in a time-dependent manner. GlyR-β promoted potential angiogenesis and neurological regeneration in affected brain tissue, thus promoting recovery from cerebral ischemia stroke/reperfusion.

MZT2A serves as a prognostic biomarker and promotes the progression of kidney renal clear cell carcinoma

MZT2A is a novel core component in the γ-tubulin ring complex and aberrantly expressed in some types of tumors. However, MZT2A expression pattern across different cancers and its role in kidney renal clear cell carcinoma have not been sufficiently investigated. A thorough analysis of MZT2A expression landscape across 33 cancer types was conducted, utilizing 712 normal samples and 9807 tumor samples from TCGA (version 37.0), as well as 5112 normal samples from the GTEx databases. MZT2A's impact on KIRC cell viability and proliferation were evaluated through BrdU assays and monitored by cell imaging readers in MZT2A-expressing plasmid or siRNA-transfected cells. Additionally, the effects of MZT2A on cell apoptosis and cell cycle were detected using flow cytometry and Western blot. WGCNA analysis was employed to construct a co-expression gene network associated with MZT2A expression in KIRC, and Pearson correlation coefficient was utilized to examine the relationships between pairs of genes. MZT2A is overexpressed in 25 out of 33 types of cancer, including KIRC. In KIRC, high level of MZT2A was associated with higher clinical stage progression and poorer patients' survival. Downregulation of MZT2A decreased KIRC cell proliferation, retarded cell cycle and promoted apoptosis, while upregulation of MZT2A produced the opposite effects. WGCNA analysis and in vitro experiments revealed that MZT2A activated PI3K/AKT signaling pathway in KIRC. In all, MZT2A was overexpressed in most types of tumors. MZT2A served as an oncogene in KIRC and might be a potential target for guiding future treatments.

Antiproliferative effects of LY-2183240 combined with various chemotherapeutic drugs in an isobolographic in vitro model of malignant melanoma

Despite a great progress in identifying treatment options for patients with malignant melanoma, novel therapies tend to be costly and, in some cases, produce adverse effects forcing the melanoma patients to withdraw drugs. There is a strong need for less expensive drugs with a more favorable spectrum of anticancer actions. This study was designed to assess whether LY-2183240 (a potent inhibitor of both, anandamide cellular reuptake and fatty acid amide hydrolase (FAAH), an enzyme that degrades anandamide) has antiproliferative and cytotoxic effects on various human malignant melanoma cell lines (primary A375 and FM55P, metastatic SK-MEL28 and FM55M2) when administered alone or in combination with docetaxel, paclitaxel, mitoxantrone and cisplatin via the MTT assay. The MTT, LDH and BrdU assays were used to evaluate the potency and safety of LY-2183240, whereas isobolographic analysis of interactions was applied to characterize the interactions of LY-2183240 with the studied chemotherapeutics (docetaxel, paclitaxel, mitoxantrone and cisplatin). The isobolography confirmed that the combinations of LY-2183240 with docetaxel, paclitaxel and mitoxantrone produced additive interactions in all the tested melanoma cell lines. Only two antagonistic interactions for LY-2183240 combined with cisplatin in the A375 and FM55P cell lines were observed by the MTT assay. In conclusion, LY-2183240 can be considered an add-on drug for the treatment of melanoma, when combined with docetaxel, paclitaxel, or mitoxantrone, but not with cisplatin.

Hemicentin-1 is an essential extracellular matrix component during tooth root formation by promoting mesenchymal cells differentiation.

Introduction: Root dentin formation is an important process in tooth development. We tried to identify potential genes that regulate root dentin formation which could be potentially used for the regeneration and repair of defective or damaged dental roots. Methods: Tissues harvested from the labial and lingual sides of mouse incisors were used for microarray analysis. Gene ontology (GO) analysis of differentially expressed genes indicated the critical role of extracellular matrix in the discrepancy of dentin formation between root and crown, for which hemicentin-1 (Hmcn1) was selected as the target gene. Single-cell RNA sequencing analysis the expression pattern of Hmcn1 at different developmental stages in mouse molars. The spatiotemporal expression of HMCN1 in mouse incisors and molars was detected by immunohistochemical staining. The functions of HMCN1 in human dental pulp cells, including proliferation, differentiation and migration, were examined in vitro by CCK8 assay, BrdU assay, wound-healing assay, ALP staining and alizarin red staining, respectively. Results: It was showed that HMCN1 expression was more pronounced in papilla-pulp on the root than crown side in mouse incisors and molars. In vitro experiments presented inhibited dentinogenesis and migration after HMCN1-knockdown in human dental pulp cells, while there was no significant difference in proliferation between the HMCN1-knockdown group and control group. Discussion: These results indicated that HMCN1 plays an important role in dentinogenesis and migration of pulp cells, contributing to root dentin formation.

Stem Cell Therapy Using Bone Marrow-Derived Muse Cells Repairs Radiation-Induced Intestinal Injury Through Their Intestine-Homing via Sphingosine Monophosphate-Sphingosine Monophosphate Receptor 2 Interaction

PurposeThere is still no effective treatment for the gastrointestinal side effects of radiation therapy. Multilineage-differentiating stress enduring (Muse) cells are tissue stem cells that have the ability to spontaneously homing in on injured tissues and repairing them. Several clinical trials have shown that stem cell therapy using human bone marrow-derived Muse (hBM-Muse) cells is effective in treating various diseases, but it is not known whether they are effective in treating radiation-induced intestinal injury. In this study, we investigated whether hBM-Muse cells homing to the radiation-damaged intestine and promote its repair. Methods and MaterialshBM-Muse cells were injected into the tail vein of mice 2 hours after high-dose total body irradiation. Then, homing analysis, crypt assay, BrdU assay, TUNEL assay, immunostaining, and survival time measurements were performed. In addition, we analyzed the expression of sphingosine monophosphate (S1P), a Muse cell inducing factor, in the mouse small intestine after irradiation. Finally, we investigated whether administration of JTE-013, an S1P receptor 2 (S1PR2)-specific antagonist, inhibits hBM-Muse cells homing to the injured intestine. ResultsS1P expression increased in mouse intestine after irradiation, with hBM-Muse cells homing in on the injured intestine. Injection of hBM-Muse cells after radiation exposure significantly increased the number of crypts, proliferating cells in the crypts, and small intestinal component cells such as intestinal stem cells, inhibited radiation-induced apoptosis, and prolonged mouse survival. Treatment with JTE-013 significantly inhibited intestinal homing and therapeutic effects of hBM-Muse cells. These findings indicate that hBM-Muse cells homed in on the injured intestine through the S1P-S1PR2 interaction to exert therapeutic effects on the radiation-induced intestinal injury. ConclusionThis study indicates that hBM-Muse cells are effective in treating radiation-induced intestinal injury, suggesting that hBM-Muse cell-based stem cell therapy has the potential to overcome the gastrointestinal side effects that limit the indications for radiation therapy.

Rhizoma coptidis can inhibit the excessive proliferation, inflammation, and transformation of lung fibroblasts into myofibroblasts.

Pulmonary fibrosis (PF) is a chronic, progressive, and irreversible heterogeneous disease of lung interstitial tissue. To combat progression of PF, new drugs are required to be developed. Rhizoma coptidis (COP), one of the main alkaloids of Coptis chinensis, is a traditional herbal medicine used to treat various inflammatory diseases. To investigate the possible effects of Coptisine (Cop) on the growth, inflammation, as well as FMT of TNF-β1-induced HFL1 cells and uncover the mechanism. Human fetal lung fibroblast 1 (HFL1) was induced using 6ng/mL TGF-β1 as a model of pulmonary fibrosis. CCK-8, Brdu, and transwell assays indicated the effects on cell growth as well as motility. qPCR and the corresponding kits indicted the effects on cell inflammation. Immunoblot showed the effects on FMT and further confirmed the mechanism. Coptisine inhibits excessive growth as well as motility of TNF-β1-induced HFL1 cells. It further inhibits inflammation and ROS levels in TNF-β1-induced HFL1 cells. Coptisine inhibits the FMT process of TNF-β1-induced HFL1 cells. Mechanically, coptisine promotes the Nrf2/HO-1 pathway. Coptisine can inhibit the excessive growth, inflammation as well as FMT of lung fibroblasts into myofibroblasts. It could serve as a promising drug of PF.

TL1A Promotes Fibrogenesis in Colonic Fibroblasts via the TGF-β1/Smad3 Signaling Pathway.

Intestinal fibrosis is a refractory complication of inflammatory bowel disease (IBD). Tumor necrosis factor ligand-related molecule-1A (TL1A) is important for IBD-related intestinal fibrosis in a dextran sodium sulfate (DSS)-induced experimental colitis model. This study aimed to explore the effects of TL1A on human colonic fibroblasts. A trinitrobenzene sulfonic acid (TNBS)-induced experimental colitis model of LCK-CD2-TL1A-GFP transgenic (Tg) or wild-type (WT) mice was established to determine the effect and mechanism of TL1A on intestinal fibrosis. The human colonic fibroblast CCD-18Co cell line was treated concurrently with TL1A and human peripheral blood mononuclear cell (PBMC) supernatant. The proliferation and activation of CCD-18Co cells were detected by BrdU assays, flow cytometry, immunocytochemistry and Western blotting. Collagen metabolism was tested by Western blotting and real-time quantitative polymerase chain reaction (RT-qPCR). The level of collagen metabolism in the TNBS+ethyl alcohol (EtOH)/Tg group was greater than that in the TNBS+EtOH/WT group. Transforming growth factor-β1 (TGF-β1) and p-Smad3 in the TNBS+EtOH/Tg group were upregulated as compared with those in the TNBS+EtOH/WT group. The proliferation of CCD-18Co cells was promoted by the addition of human PBMC supernatant supplemented with 20 ng/mL TL1A, and the addition of human PBMC supernatant and TL1A increased CCD-18Co proliferation by 24.4% at 24 h. TL1A promoted cell activation and increased the levels of COL1A2, COL3A1, and TIMP-1 in CCD-18Co cells. Treatment of CCD-18Co cells with TL1A increased the expression of TGF-β1 and p-Smad3. TL1A promotes TGF-β1-mediated intestinal fibroblast activation, proliferation, and collagen deposition and is likely related to an increase in the TGF-β1/Smad3 signaling pathway.

MicroRNA-31-5p is upregulated during neointima formation and influences human coronary artery smooth muscle cell functions by regulating PIAS3 and DKK1

Abstract Funding Acknowledgements None. Background and purpose MicroRNAs (miRs) have emerged as potential therapeutic targets in cardiovascular disease, given their ability to modulate multiple signaling pathways and cellular processes. Neointima formation as an angioplasty-related complication remains a major issue calling for innovative therapeutic options and is predominantly mediated by phenotypic and functional changes of vascular smooth muscle cells. Here, we propose that targeting miR-31-5p might be an effective approach to selectively modulate smooth muscle cell functions to enhance vascular healing and regeneration. Methods C57J/BlL6 mice (n=6, 3 months, male) were subjected to wire-induced femoral artery injury. At days 10 and 21 after injury, femoral arteries were harvested for miRNA analysis. Expression levels of miR-31-5p were confirmed by qRT-PCR in human coronary artery endothelial cells (HCAEC) and -smooth muscle cells (HCASMC). Further, the effect of miR-31-5p on cellular functions was investigated on HCAECs and HCASMCs in vitro, including migration (scratch assay), proliferation (BrdU assay), and apoptosis. Possible targets of miR-31-5p were identified in silico by structured literature research and target binding prediction and confirmed on mRNA and protein levels. High-resolution microscopy analysis was used to investigate morphological changes. Results Expression analysis revealed a significant upregulation of miR-31-5p (p<0.0001) in murine femoral artery neointimal tissue at 7 and 21 days. In vitro, miR-31-5p was significantly upregulated in HCASMC (p<0,05) but not HCAEC following serum stimulation. On a functional level, miR-31-5p revealed dissenting effects on HCAEC and HCASMC. Whereas migration and proliferation are not altered in HCAECs, knockdown of miR-31-5p significantly reduced migration (p<0,01), proliferation (p<0,05), and increased apoptosis (p<0,05) in HCASMCs. Additionally, the knockdown of miR-31-5p influenced the phenotypical switch of HCASMC towards a contractile phenotype. Under these conditions, the release of cytokines like TNF-alpha and IL1-beta was also significantly reduced (p<0,05) in HCASMCs. Systematic in silico target screens suggested DKK1 and PIAS3 as potential direct targets. Indeed, knockdown of miR-31-5p resulted in a significant upregulation of DKK1 in HCASMC (p<0,05) on mRNA level and DKK1 (p<0,05) and PIAS3 (p<0,05) on mRNA and protein level. An overexpression resulted in a significant downregulation of DKK1 in HCASMC (p<0,05) on mRNA level. Conclusion In conclusion, we report that miR-31-5p is robustly upregulated during neointima formation and seems to exert a functional neointima formation-promoting role in HCASMC rather than HCAEC. Mechanistically, DKK1 and PIAS3 as direct targets of miR-31-5p can mediate the observed effects. Thus, miR-31-5p might represent an attractive target to selectively modulate HCASMC dysfunction following vascular intervention, limiting neointima formation in treated vessels.

MiR-32-5p as potential key mediator of vascular remodeling enhances cell proliferation of vascular smooth muscle cells

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): University Hospital Halle, Martin-Luther-University Halle-Wittenberg Background and purpose The dysfunctionality of endothelial cells (EC) and smooth muscle cells (SMC) contributes to the progression of vascular remodeling and subsequent cardiovascular pathologies. Several microRNAs (miRNA) have been revealed as key regulators of EC and SMC function, therefore suggesting them as potential targets in the modulation of vascular remodeling. Here, we investigate the potential role of miR-32-5p in vascular cell function and its potential as a therapeutic target in vascular remodeling. Material and Methods Initial screenings by qRT-PCR analysis for miR-32-5p expression were performed in murine femoral artery tissue on day 10 and 21 after wire-induced injury in C57Bl6 mice, serving as restenosis model. MiR-32-5p expression was assessed using qRT-PCR in human vascular endothelial (HVECs) and human vascular smooth muscle cells (HVSMC). The role of miR-32-5p on cellular functions, as migration and proliferation, was determined by performing scratch wound and BrdU assays. Potential miR-32-5p downstream targets were identified from literature and their expression levels upon interference with miR-32-5p evaluated on mRNA and protein levels. Results MiR-32-5p expression was decreased over time in the wire-induced injury model. In vitro, miR-32-5p expression was significantly decreased in replicative senescent HVSMC and HVEC (p<0,05) and relatively higher in HVSMC than in HVEC for all conditions. Under growth conditions an elevated expression of miR-32-5p in HVEC and significantly increased expression in HVSMC was detected (p<0,01). Proliferation in HVSMC increased significantly (p<0,05) by pre-miR-32-5p transfection, but remained unaffected in HVEC. Migration of HVECs and HVSMCs was improved by miR-32-5p and decelerated after antagomiR interference. Systemic literature target research revealed several potential targets in both cell types, of which the following were significantly downregulated in HVSMC after pre-miR transfection including PIK3r3 (p<0,05), KLF4 (p<0,05), CD69 (p<0,01), MAP2K4 (p<0,05) and BCL211 (p<0,01). Additionally, CD69 and KLF4 expression increased significantly either in HVECs (p<0,05). Conclusion Our results suggest that miR-32-5p may be a substantial regulator in HVEC and HVSMC senescence and function and subsequently in vascular remodeling. To fully evaluate its role in the pathogenesis of atherosclerosis and therefore, its therapeutic potential in cardiovascular diseases, further investigations are needed. Additional experiments with the purpose of investigating miR-32-5p-target interactions and apoptotic effects will be performed shortly.

Gprc5a is a novel parathyroid hormone-inducible gene and negatively regulates osteoblast proliferation and differentiation.

Teriparatide is a peptide derived from a parathyroid hormone (PTH) and an osteoporosis therapeutic drug with potent bone formation-promoting activity. To identify novel druggable genes that act downstream of PTH signaling and are potentially involved in bone formation, we screened PTH target genes in mouse osteoblast-like MC3T3-E1 cells. Here we show that Gprc5a, encoding an orphan G protein-coupled receptor, is a novel PTH-inducible gene and negatively regulates osteoblast proliferation and differentiation. PTH treatment induced Gprc5a expression in MC3T3-E1 cells, rat osteosarcoma ROS17/2.8 cells, and mouse femurs. Induction of Gprc5a expression by PTH occurred in the absence of protein synthesis and was mediated primarily via the cAMP pathway, suggesting that Gprc5a is a direct target of PTH signaling. Interestingly, Gprc5a expression was induced additively by co-treatment with PTH and 1α, 25-dihydroxyvitamin D3 (calcitriol), or retinoic acid in MC3T3-E1 cells. Reporter analysis of a 1 kb fragment of human GPRC5A promoter revealed that the promoter fragment showed responsiveness to PTH via the cAMP response element, suggesting that GPRC5A is also a PTH-inducible gene in humans. Gprc5a knockdown promoted cell viability and proliferation, as demonstrated by MTT and BrdU assays. Gprc5a knockdown also promoted osteoblast differentiation, as indicated by gene expression analysis and mineralization assay. Mechanistic studies showed that Gprc5a interacted with BMPR1A and suppressed BMP signaling induced by BMP-2 and constitutively active BMP receptors, ALK2 (ACVR1) Q207D and ALK3 (BMPR1A) Q233D. Thus, our results suggest that Gprc5a is a novel gene induced by PTH that acts in an inhibitory manner on both cell proliferation and osteoblast differentiation and is a candidate for drug targets for osteoporosis.

MitoQ Treatment Mitigates Senescence Burden in DOXO-Induced Senescent Endothelial Cells Through Reductions in mtROS and DNA Damage

Cardiovascular toxicity is one of the adverse consequences of chemotherapy that limits treatment. Specifically, chemotherapeutics such as doxorubicin (DOXO) can lead to endothelial dysfunction through the induction of reactive oxygen species (ROS) and mitochondrial ROS (mtROS) production. MtROS are chemically reactive molecules generated as byproducts of oxidative phosphorylation during mitochondrial respiration. DOXO exacerbates its cardiotoxic effects by amplifying mtROS production, leading to an increase in DNA damage and cell senescence, particularly in endothelial cells (ECs). MitoQ is a mitochondria-targeted antioxidant designed to accumulate within the mitochondria and mitigate oxidative damage by neutralizing mtROS. However, whether MitoQ can rescue mtROS-induced DNA damage and senescence remains elusive. Here, we tested the hypothesis that MitoQ will attenuate DOXO-induced mtROS thus blunting DNA damage and subsequent EC senescence. Human umbilical vein endothelial cells (HUVECs) were simultaneously subjected to 24-hour treatments with DOXO (250nM) and MitoQ (250nM). To evaluate the antioxidative effect of the MitoQ, we examined mitochondrial superoxide using MitoSOX. The results demonstrated that DOXO increases mitochondrial superoxide by 40% (Fig1, p=0.019), whereas addition of MitoQ (MitoQ+DOXO) attenuated mitochondrial superoxide significantly compared to the DOXO group (Fig1, p=0.033). Gene expression of senescence markers, p16 and p21, and Senescence Associated Secretory Phenotypes (SASPs) factors were also examined to assess the effect of MitoQ on senescent endothelial cells. p16 was significantly reduced in the MitoQ+DOXO treatment group compared to the DOXO alone (Fig2, p=0.0090). MitoQ+DOXO lowered p21 expression by 35%, although this difference did not reach significance (Fig2, p=0.340). Moreover, MitoQ+DOXO reduced the SASP factors, IL-8, IL-6 and MCP-1, by more than 54% in comparison to the DOXO group (Fig2, all p≤0.027). Senescent endothelial cells were examined for 53BP1, a double-stranded DNA break marker, using an immunofluorescence (IF) assay. MitoQ+DOXO reduced 53BP1 by 32.6% compared to the DOXO-treated group (Fig3, p=0.011). We also assessed cell proliferation using Bromodeoxyuridine (BrdU) assay. In line with other results, the BrdU assay indicates that the proliferative capability of MitoQ+DOXO-treated cells was improved by more than 20% compared to DOXO-induced senescent cells (Fig4, p=0.008). Our findings suggest that MitoQ can mitigate DOXO-induced mtROS, attenuate DNA damage, and ameliorate senescence in endothelial cells. This provides mechanistic insight suggesting that mtROS may be a driver of cellular senescence in ECs via an increase in DNA damage and MitoQ may be an effcacious therapeutic to treat chemotherapy-induced cardiovascular toxicity. Funded in part by awards from National Institutes of Health Awards R01 AG060395, R01 AG048366, T32 HL139451, F31 AG076312, R01 AG077751, R01 AG076748, Nora Eccles Treadwell foundation (NETF), and Veteran's Affairs Merit Review Award I01 BX004492. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Linarin Ameliorates Restenosis After Vascular Injury in Type 2 Diabetes Mellitus via Regulating ADAM10-Mediated Notch Signaling Pathway.

Vascular lesions frequently arise as complication in patients diagnosed with diabetes mellitus (DM). Presently, percutaneous coronary intervention (PCI) and antithrombotic therapy serve as primary treatments. However, in-stent restenosis persists as a challenging clinical issue following PCI, lacking sustained and effective treatment. Linarin (LN) exhibits diverse pharmacological activities and is regarded as a potential drug for treating various diseases, including DM. But its specific role in restenosis after vascular injury in DM patients remains unclear. A rat model of diabetes-related restenosis was established to evaluate the role of LN on neointimal hyperplasia. Vascular smooth muscle cells (VSMCs) stimulated by high glucose (HG, 30mM) underwent LN treatment. Additionally, an overexpression plasmid of A disintegrin and metalloproteinases (ADAM10) was constructed to transfect VSMCs. We employed CCK-8, Brdu, wound-healing scratch, and transwell migration assays to evaluate the proliferation and migration of VSMCs. Furthermore, western blot and immunofluorescence assays were utilized to investigate the expressions of ADAM10 and the downstream Notch signaling pathway in vivo and in vitro models. LN notably alleviated intimal hyperplasia after vascular injury in DM rats and reduced the protein expression of ADAM10, alongside its downstream Notch1 signaling pathway-related proteins (Notch1, NICD and Hes1) in rat carotid artery tissues. LN effectively suppressed the proliferation and migration of VSMCs induced by HG, downregulating the protein expression of ADAM10, Notch1, NICD and Hes1. Moreover, our findings indicated that ADAM10 overexpression significantly reversed LN's effects on proliferation, migration, and the expression of Notch1 signaling pathway-related proteins in HG-treated VSMCs. LN demonstrates potential therapeutic efficacy in addressing restenosis after diabetic-related vascular injury, with the ADAM10 mediated Notch signaling pathway playing a pivotal role.

Abstract 3122: The Role Of Oct4 In Endothelial Cell Sexual Dimorphism And Angiogenesis

Background: Biological sex differences play a critical role in vascular diseases. Using endothelial ( EC ) lineage tracing atherosclerotic mice and cultured mouse and human aortic EC, we recently found that female EC have lower angiogenic potential, higher expression of pro-inflammatory genes and intracellular ROS, and worse mitochondria functions than male EC. However, the mechanisms responsible for this EC sexual dimorphism are still unknown. We previously identified the pluripotency factor OCT4 as a critical regulator of EC characteristics, including angiogenic potential, ROS accumulation, and mitochondrial functions. Therefore, this study aimed to test whether OCT4 is responsible for sex-dependent differences in EC in vivo and in vitro . Methods: We used male and female EC-specific tamoxifen-inducible OCT4 knockout and EC-lineage tracing (EC-OCT4 KO) mice to study the role of OCT4 in non-atherosclerotic conditions leading to pro-inflammatory angiogenesis, such as hind-limb ischemia and skin injury models. Male and female mouse aortic EC (MAEC) were isolated from EC-OCT4 KO and wild-type littermate mice for in vitro experiments. We performed BrdU assay, EC tube formation in Matrigel (in vitro angiogenesis), wound scratch assay, and angiogenic proteome profile array to evaluate angiogenic potential. Results: Compared to wild-type mice, EC-OCT4 KO male mice exhibited accelerated blood flow recovery and wound healing after hind-limb ischemia and skin injury. However, EC-OCT4 KO female mice showed no difference in blood flow recovery and delayed skin wound healing compared to control mice. In vitro , although male and female OCT4-KO MAEC had higher angiogenic potential than control, the phenotype in female EC was less pronounced. Mechanistically, we found that male OCT4 KO MAEC express higher levels of monocyte cytokine protein 1 ( MCP1 ). Furthermore, the inhibition of MCP1 in male OCT4 KO MAEC, but not in female cells, led to significant decreases in cell migration, proliferation, and endothelial tube formation in Matrigel. Conclusions: Our data indicate that OCT4-dependent mechanisms contribute to the sex differences observed in EC, suggesting a novel biological role for pluripotency signaling in vascular pathologies and homeostasis.

STK16 promoted colorectal cancer progress in a c-MYC signaling-dependent manner

BackgroundColorectal cancer standed as a global health challenge, ranking third in cancer incidence and second in cancer-related deaths worldwide. A deeper understanding of the intricate mechanisms driving colorectal cancer development was pressing need. STK16 had garnered attention in recent researches, while its involvement in cancer had been minimally explored. c-MYC had emerged as a key player in cancer biology. Due to its complex structure, multifunctionality, and intricate interactions, directly inhibiting the activity of c-MYC proves to be challenging. Hence, current research was directing efforts towards modulating c-MYC expression levels.MethodsImmunoblot, Immunohistochemistry and immunoprecipitation assays were conducted to assess the indicated protein expression levels. RT-PCR was performed to detect the corresponding mRNA expression levels. The proliferation, migration, invasion, and colony formation abilities of the specified cancer cells were investigated using CCK8 assays, Brdu assays, transwell assays, and colony formation assays, respectively. Cellular and animal experiments were performed to investigate the correlation between STK16 signaling and c-MYC signaling.ResultsSTK16 plays a positive regulatory role in the progression of colorectal cancer. Delving into the molecular mechanisms, we unveiled that STK16 phosphorylated c-MYC at serine 452, a pivotal event hindering the ubiquitin-proteasome pathway degradation of c-MYC. Importantly, colorectal cancer proliferation mediated by STK16 was found to be dependent on the phosphorylation of c-MYC at S452. Furthermore, the researchers demonstrated that STK16 knockout or pharmacological inhibition significantly curtailed colorectal cancer proliferation and c-MYC expression in in vivo animal models.ConclusionWe discovered that STK16 phosphorylates c-MYC at serine 452, hindering its degradation via the ubiquitin-proteasome pathway. STK16 inhibition, either genetically or pharmacologically, effectively curtails cancer growth and c-MYC expression in vivo. These findings highlight STK16 as a potential therapeutic target for colorectal cancer.