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Deng Y, Huang X, Yang Y, Zhang Y, Zeng B, Bao Y, Cao L, Wang X, Ma L, Wang J. MFAP2 upregulation promotes ESCC metastasis via FAK-AKT signaling pathway. FASEB J 2024; 38:e70266. [PMID: 39698924 DOI: 10.1096/fj.202402411r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2024] [Revised: 11/29/2024] [Accepted: 12/10/2024] [Indexed: 12/20/2024]
Abstract
Metastasis is the leading cause of mortality from esophageal squamous cell carcinoma (ESCC). By the time of diagnosis, most ESCC tumors have already invaded the lymph nodes or distant organs; however, it has been challenging to identify and confirm genes with a crucial role in ESCC metastasis. The microfibrillar-associated protein 2 (MFAP2) is upregulated in human ESCC, and its expression level was positively associated with poor overall and disease-free survival. Consistently, upregulation of MFAP2 promoted the metastasis and invasion of ESCC cells in vitro and in vivo. Conversely, these processes were reduced by MFAP2 knockdown. Mechanistically, MFAP2 was shown to bind to the FERM domain of focal adhesion kinase (FAK) and to alleviate FAK intramolecular inhibition, resulting in the enhanced binding affinity between FAK and integrin beta 4 (ITGB4) and activation of the FAK-AKT signaling pathway. Treatment of ESCC cells with the FAK inhibitor PND-1186 reduced MFAP2, induced the activation of the FAK-AKT pathway in vitro, and suppressed lung metastasis in a mouse model of ESCC. These findings support a major role for MFAP2 in promoting ESCC metastasis, in part via the activation of FAK-AKT signaling, and highlight the potential of MFAP2 as a promising therapeutic target for ESCC.
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Luo X, Liu L, Rong H, Liu X, Yang L, Li N, Shi H. ENU-based dominant genetic screen identifies contractile and neuronal gene mutations in congenital heart disease. Genome Med 2024; 16:97. [PMID: 39135118 PMCID: PMC11318149 DOI: 10.1186/s13073-024-01372-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Accepted: 08/05/2024] [Indexed: 08/15/2024] Open
Abstract
BACKGROUND Congenital heart disease (CHD) is the most prevalent congenital anomaly, but its underlying causes are still not fully understood. It is believed that multiple rare genetic mutations may contribute to the development of CHD. METHODS In this study, we aimed to identify novel genetic risk factors for CHD using an ENU-based dominant genetic screen in mice. We analyzed fetuses with malformed hearts and compared them to control littermates by whole exome or whole genome sequencing (WES/WGS). The differences in mutation rates between observed and expected values were tested using the Poisson and Binomial distribution. Additionally, we compared WES data from human CHD probands obtained from the Pediatric Cardiac Genomics Consortium with control subjects from the 1000 Genomes Project using Fisher's exact test to evaluate the burden of rare inherited damaging mutations in patients. RESULTS By screening 10,285 fetuses, we identified 1109 cases with various heart defects, with ventricular septal defects and bicuspid aortic valves being the most common types. WES/WGS analysis of 598 cases and 532 control littermates revealed a higher number of ENU-induced damaging mutations in cases compared to controls. GO term and KEGG pathway enrichment analysis showed that pathways related to cardiac contraction and neuronal development and functions were enriched in cases. Further analysis of 1457 human CHD probands and 2675 control subjects also revealed an enrichment of genes associated with muscle and nervous system development in patients. By combining the mice and human data, we identified a list of 101 candidate digenic genesets, from which each geneset was co-mutated in at least one mouse and two human probands with CHD but not in control mouse and control human subjects. CONCLUSIONS Our findings suggest that gene mutations affecting early hemodynamic perturbations in the developing heart may play a significant role as a genetic risk factor for CHD. Further validation of the candidate gene set identified in this study could enhance our understanding of the complex genetics underlying CHD and potentially lead to the development of new diagnostic and therapeutic approaches.
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Smetanina M, Korolenya V, Sipin F, Oscorbin I, Sevostyanova K, Gavrilov K, Shevela A, Filipenko M. Loci cg06256735 and cg15815843 in the MFAP5 gene regulatory regions are hypomethylated in varicose veins apparently due to active demethylation. Biosci Rep 2024; 44:BSR20231938. [PMID: 38743016 PMCID: PMC11139664 DOI: 10.1042/bsr20231938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Revised: 05/10/2024] [Accepted: 05/14/2024] [Indexed: 05/16/2024] Open
Abstract
Varicose vein disease (VVD) is a common health problem worldwide. Microfibril-associated protein 5 (MFAP5) is one of the potential key players in its pathogenesis. Our previous microarray analysis revealed the cg06256735 and cg15815843 loci in the regulatory regions of the MFAP5 gene as hypomethylated in varicose veins which correlated with its up-regulation. The aim of this work was to validate preliminary microarray data, estimate the level of 5-hydroxymethylcytosine (5hmC) at these loci, and determine the methylation status of one of them in different layers of the venous wall. For this, methyl- and hydroxymethyl-sensitive restriction techniques were used followed by real-time PCR and droplet digital PCR, correspondingly, as well as bisulfite pyrosequencing of +/- oxidized DNA. Our microarray data on hypomethylation at the cg06256735 and cg15815843 loci in whole varicose vein segments were confirmed and it was also demonstrated that the level of 5hmC at these loci is increased in VVD. Specifically, among other layers of the venous wall, tunica (t.) intima is the main contributor to hypomethylation at the cg06256735 locus in varicose veins. Thus, it was shown that hypomethylation at the cg06256735 and cg15815843 loci takes place in VVD, with evidence to suggest that it happens through their active demethylation leading to up-regulation of the MFAP5 gene, and t. intima is most involved in this biochemical process.
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Yang H, Zhou T, Liu B. Macrophage-mediated downregulation of lncRNA Carmn in mouse abdominal aortic aneurysm. Vascul Pharmacol 2024; 154:107264. [PMID: 38097098 PMCID: PMC10939852 DOI: 10.1016/j.vph.2023.107264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 12/03/2023] [Accepted: 12/07/2023] [Indexed: 12/18/2023]
Abstract
The long noncoding RNA (lncRNA) CARMN (cardiac mesoderm enhancer associated noncoding RNA) is a highly conserved lncRNA that expresses primarily by smooth muscle cells (SMCs). Recent literature demonstrates that CARMN plays a critical role in the differentiation and maintaining of the contractile state of vascular SMCs. Because aortic SMCs show diminished contractile proteins in abdominal aortic aneurysms (AAAs), we hypothesize that the expression of CARMN is downregulated in the aortic wall affected by aneurysm. In this study, we analyzed publicly available single-cell or bulk RNA sequencing data comparing healthy and aneurysmal mouse aortic tissues. In both healthy and diseased aortas, Carmn expression was enriched in SMCs characterized by the high expression of SMC-specific contractile proteins including Myh11 and Acta2. Carmn expression levels varied among the sub-clusters of SMCs and consequently along the aortic tree. Comparing to the corresponding sham aorta, aortas from 3 distinct AAA models contained less Carmn. To validate the Carmn downregulation, we induced AAA using the Angiotensin II and CaCl2 models. In situ hybridization showed that Carmn mRNA located in the nuclei of SMCs and became downregulated within a few days following the aneurysm induction. Mechanistically, we tested whether Carmn expression is regulated by infiltrating macrophages --- the predominant inflammatory cells found in aneurysmal tissues --- by treating healthy mouse aortic SMCs with media conditioned by macrophages primed with pro-inflammatory or anti-inflammatory cytokines. PCR analysis showed that inflammatory macrophages reduced the expression of Carmn and contractile genes including Myh11 and Acta2. Taken together, our results from bioinformatic and experimental analyses demonstrate that Carmn is downregulated in different AAA models, likely by inflammatory macrophages. The negative regulation of Carmn in AAA tissues may explain at least in part the loss of SMC contractile state during the pathogenesis of this progressive degenerative disease.
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Schultz MLC, Seth P, Kachmar L, Ijpma G, Lauzon AM. A method for isolating contractile smooth muscle cells from cryopreserved tissue. Am J Physiol Cell Physiol 2024; 326:C990-C998. [PMID: 38314725 DOI: 10.1152/ajpcell.00442.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 01/11/2024] [Accepted: 01/27/2024] [Indexed: 02/07/2024]
Abstract
Multiple techniques have been developed to isolate contractile smooth muscle cells (SMCs) from tissues with varying degrees of success. However, most of these approaches rely on obtaining fresh tissue, which poses logistical challenges. In the present study, we introduce a novel protocol for isolating contractile SMCs from cryopreserved smooth muscle (SM) tissue, thereby enhancing experimental efficiency. This protocol yields abundant viable, spindle-shaped, contractile SMCs that closely resemble those obtained from fresh samples. By analyzing the expression of contractile proteins, we demonstrate that both the isolated SMCs from cryopreserved tissue represent more accurately fresh SM tissue compared with cultured SMCs. Moreover, we demonstrate the importance of a brief incubation step of the tissue in culture medium before cell dissociation to achieve contractile SMCs. Finally, we provide a concise overview of our protocol optimization efforts, along with a summary of previously published methods, which could be valuable for the development of similar protocols for other species.NEW & NOTEWORTHY We report a successful protocol development for isolating contractile smooth muscle cells (SMCs) from cryopreserved tissue reducing the reliance on fresh tissues and providing a readily available source of contractile SMCs. Our findings suggest that SMCs isolated using our protocol maintain their phenotype better compared with cultured SMCs. This preservation of the cellular characteristics, including the expression of key contractile proteins, makes these cells more representative of fresh SM tissue.
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Hsu CR, Sangha G, Fan W, Zheng J, Sugioka K. Contractile ring mechanosensation and its anillin-dependent tuning during early embryogenesis. Nat Commun 2023; 14:8138. [PMID: 38065974 PMCID: PMC10709429 DOI: 10.1038/s41467-023-43996-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023] Open
Abstract
Cytokinesis plays crucial roles in morphogenesis. Previous studies have examined how tissue mechanics influences the position and closure direction of the contractile ring. However, the mechanisms by which the ring senses tissue mechanics remain largely elusive. Here, we show the mechanism of contractile ring mechanosensation and its tuning during asymmetric ring closure of Caenorhabditis elegans embryos. Integrative analysis of ring closure and cell cortex dynamics revealed that mechanical suppression of the ring-directed cortical flow is associated with asymmetric ring closure. Consistently, artificial obstruction of ring-directed cortical flow induces asymmetric ring closure in otherwise symmetrically dividing cells. Anillin is vital for mechanosensation. Our genetic analysis suggests that the positive feedback loop among ring-directed cortical flow, myosin enrichment, and ring constriction constitutes a mechanosensitive pathway driving asymmetric ring closure. These findings and developed tools should advance the 4D mechanobiology of cytokinesis in more complex tissues.
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Tierney JW, Evans BC, Cheung-Flynn J, Wang B, Colazo JM, Polcz ME, Cook RS, Brophy CM, Duvall CL. Therapeutic MK2 inhibition blocks pathological vascular smooth muscle cell phenotype switch. JCI Insight 2021; 6:e142339. [PMID: 34622803 PMCID: PMC8525639 DOI: 10.1172/jci.insight.142339] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/01/2021] [Indexed: 11/17/2022] Open
Abstract
Vascular procedures, such as stenting, angioplasty, and bypass grafting, often fail due to intimal hyperplasia (IH), wherein contractile vascular smooth muscle cells (VSMCs) dedifferentiate to synthetic VSMCs, which are highly proliferative, migratory, and fibrotic. Previous studies suggest MAPK-activated protein kinase 2 (MK2) inhibition may limit VSMC proliferation and IH, although the molecular mechanism underlying the observation remains unclear. We demonstrated here that MK2 inhibition blocked the molecular program of contractile to synthetic dedifferentiation and mitigated IH development. Molecular markers of the VSMC contractile phenotype were sustained over time in culture in rat primary VSMCs treated with potent, long-lasting MK2 inhibitory peptide nanopolyplexes (MK2i-NPs), a result supported in human saphenous vein specimens cultured ex vivo. RNA-Seq of MK2i-NP-treated primary human VSMCs revealed programmatic switching toward a contractile VSMC gene expression profile, increasing expression of antiinflammatory and contractile-associated genes while lowering expression of proinflammatory, promigratory, and synthetic phenotype-associated genes. Finally, these results were confirmed using an in vivo rabbit vein graft model where brief, intraoperative treatment with MK2i-NPs decreased IH and synthetic phenotype markers while preserving contractile proteins. These results support further development of MK2i-NPs as a therapy for blocking VSMC phenotype switch and IH associated with cardiovascular procedures.
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Geller AM, Pollin I, Zlotkin D, Danov A, Nachmias N, Andreopoulos WB, Shemesh K, Levy A. The extracellular contractile injection system is enriched in environmental microbes and associates with numerous toxins. Nat Commun 2021; 12:3743. [PMID: 34145238 PMCID: PMC8213781 DOI: 10.1038/s41467-021-23777-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 05/14/2021] [Indexed: 12/26/2022] Open
Abstract
The extracellular Contractile Injection System (eCIS) is a toxin-delivery particle that evolved from a bacteriophage tail. Four eCISs have previously been shown to mediate interactions between bacteria and their invertebrate hosts. Here, we identify eCIS loci in 1,249 bacterial and archaeal genomes and reveal an enrichment of these loci in environmental microbes and their apparent absence from mammalian pathogens. We show that 13 eCIS-associated toxin genes from diverse microbes can inhibit the growth of bacteria and/or yeast. We identify immunity genes that protect bacteria from self-intoxication, further supporting an antibacterial role for some eCISs. We also identify previously undescribed eCIS core genes, including a conserved eCIS transcriptional regulator. Finally, we present our data through an extensive eCIS repository, termed eCIStem. Our findings support eCIS as a toxin-delivery system that is widespread among environmental prokaryotes and likely mediates antagonistic interactions with eukaryotes and other prokaryotes.
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Tanaka K, Osaka M, Takemori S, Watanabe M, Tanigaki S, Kobayashi Y. Contraction-associated proteins expression by human uterine smooth muscle cells depends on maternal serum and progranulin associated with gestational weight gain. Endocr J 2020; 67:819-825. [PMID: 32321883 DOI: 10.1507/endocrj.ej20-0037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Pregnant women with obesity are at increased risk of parturition dysfunction; however, the biological mechanism has remained unknown. We hypothesized that molecules circulating in the serum of pregnant women with obesity may induce the aberrant expression of contraction-associated proteins (CAPs), leading to insufficient uterine contractions. This study aimed to investigate the effects of maternal serum on CAPs expression by human uterine smooth muscle cells (UtSMCs) and elucidate the influence of maternal obesity. Blood samples were collected from singleton pregnant women at 36-41 weeks of gestation before the onset of labor. UtSMCs were incubated in the serum, and the mRNA expressions of PTGFR, OXTR, GJA1, and PTGS2 were examined by RT-PCR. Progranulin (PGRN) is a circulating glycoprotein associated with insulin resistance characterized by the accumulation of visceral fat. The serum PGRN levels of the samples were measured by ELISA. After incubated with PGRN (100-1,000 ng/mL), mRNA expression of PTGFR, OXTR, and GJA1 and protein expression of CX43 were examined by RT-PCR and western blotting, respectively. The mRNA expressions of PTGFR, OXTR, and GJA1 showed significantly negative correlations with gestational weight gain (GWG). Serum PGRN levels showed a significantly positive correlation with GWG. High levels of PGRN suppressed the mRNA expression of GJA1 and the protein expression of CX43. The change in maternal serum induced by GWG suppressed the CAPs expression by UtSMCs. PGRN is one of the factors in the serum responsible for inhibiting the expression of CX43.
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Douglas P, Ye R, Radhamani S, Cobban A, Jenkins NP, Bartlett E, Roveredo J, Kettenbach AN, Lees-Miller SP. Nocodazole-Induced Expression and Phosphorylation of Anillin and Other Mitotic Proteins Are Decreased in DNA-Dependent Protein Kinase Catalytic Subunit-Deficient Cells and Rescued by Inhibition of the Anaphase-Promoting Complex/Cyclosome with proTAME but Not Apcin. Mol Cell Biol 2020; 40:e00191-19. [PMID: 32284347 PMCID: PMC7296215 DOI: 10.1128/mcb.00191-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 05/15/2019] [Accepted: 03/31/2020] [Indexed: 11/23/2022] Open
Abstract
The DNA-dependent protein kinase catalytic subunit (DNA-PKcs) has well-established roles in DNA double-strand break repair, and recently, nonrepair functions have also been reported. To better understand its cellular functions, we deleted DNA-PKcs from HeLa and A549 cells using CRISPR/Cas9. The resulting cells were radiation sensitive, had reduced expression of ataxia-telangiectasia mutated (ATM), and exhibited multiple mitotic defects. Mechanistically, nocodazole-induced upregulation of cyclin B1, anillin, and securin was decreased in DNA-PKcs-deficient cells, as were phosphorylation of Aurora A on threonine 288, phosphorylation of Polo-like kinase 1 (PLK1) on threonine 210, and phosphorylation of targeting protein for Xenopus Klp2 (TPX2) on serine 121. Moreover, reduced nocodazole-induced expression of anillin, securin, and cyclin B1 and phosphorylation of PLK1, Aurora A, and TPX2 were rescued by inhibition of the anaphase-promoting complex/cyclosome (APC/C) by proTAME, which prevents binding of the APC/C-activating proteins Cdc20 and Cdh1 to the APC/C. Altogether, our studies suggest that loss of DNA-PKcs prevents inactivation of the APC/C in nocodazole-treated cells.
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Wang T, Li W, Martin S, Papadopulos A, Joensuu M, Liu C, Jiang A, Shamsollahi G, Amor R, Lanoue V, Padmanabhan P, Meunier FA. Radial contractility of actomyosin rings facilitates axonal trafficking and structural stability. J Cell Biol 2020; 219:e201902001. [PMID: 32182623 PMCID: PMC7199852 DOI: 10.1083/jcb.201902001] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 09/17/2019] [Accepted: 02/10/2020] [Indexed: 02/07/2023] Open
Abstract
Most mammalian neurons have a narrow axon, which constrains the passage of large cargoes such as autophagosomes that can be larger than the axon diameter. Radial axonal expansion must therefore occur to ensure efficient axonal trafficking. In this study, we reveal that the speed of various large cargoes undergoing axonal transport is significantly slower than that of small ones and that the transit of diverse-sized cargoes causes an acute, albeit transient, axonal radial expansion, which is immediately restored by constitutive axonal contractility. Using live super-resolution microscopy, we demonstrate that actomyosin-II controls axonal radial contractility and local expansion, and that NM-II filaments associate with periodic F-actin rings via their head domains. Pharmacological inhibition of NM-II activity significantly increases axon diameter by detaching the NM-II from F-actin and impacts the trafficking speed, directionality, and overall efficiency of long-range retrograde trafficking. Consequently, prolonged NM-II inactivation leads to disruption of periodic actin rings and formation of focal axonal swellings, a hallmark of axonal degeneration.
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12
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Hudalla H, Michael Z, Christodoulou N, Willis GR, Fernandez-Gonzalez A, Filatava EJ, Dieffenbach P, Fredenburgh LE, Stearman RS, Geraci MW, Kourembanas S, Christou H. Carbonic Anhydrase Inhibition Ameliorates Inflammation and Experimental Pulmonary Hypertension. Am J Respir Cell Mol Biol 2019; 61:512-524. [PMID: 30951642 PMCID: PMC6775956 DOI: 10.1165/rcmb.2018-0232oc] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 04/02/2019] [Indexed: 01/07/2023] Open
Abstract
Inflammation and vascular smooth muscle cell (VSMC) phenotypic switching are causally linked to pulmonary arterial hypertension (PAH) pathogenesis. Carbonic anhydrase inhibition induces mild metabolic acidosis and exerts protective effects in hypoxic pulmonary hypertension. Carbonic anhydrases and metabolic acidosis are further known to modulate immune cell activation. To evaluate if carbonic anhydrase inhibition modulates macrophage activation, inflammation, and VSMC phenotypic switching in severe experimental pulmonary hypertension, pulmonary hypertension was assessed in Sugen 5416/hypoxia (SU/Hx) rats after treatment with acetazolamide or ammonium chloride (NH4Cl). We evaluated pulmonary and systemic inflammation and characterized the effect of carbonic anhydrase inhibition and metabolic acidosis in alveolar macrophages and bone marrow-derived macrophages (BMDMs). We further evaluated the treatment effects on VSMC phenotypic switching in pulmonary arteries and pulmonary artery smooth muscle cells (PASMCs) and corroborated some of our findings in lungs and pulmonary arteries of patients with PAH. Both patients with idiopathic PAH and SU/Hx rats had increased expression of lung inflammatory markers and signs of PASMC dedifferentiation in pulmonary arteries. Acetazolamide and NH4Cl ameliorated SU/Hx-induced pulmonary hypertension and blunted pulmonary and systemic inflammation. Expression of carbonic anhydrase isoform 2 was increased in alveolar macrophages from SU/Hx animals, classically (M1) and alternatively (M2) activated BMDMs, and lungs of patients with PAH. Carbonic anhydrase inhibition and acidosis had distinct effects on M1 and M2 markers in BMDMs. Inflammatory cytokines drove PASMC dedifferentiation, and this was inhibited by acetazolamide and acidosis. The protective antiinflammatory effect of acetazolamide in pulmonary hypertension is mediated by a dual mechanism of macrophage carbonic anhydrase inhibition and systemic metabolic acidosis.
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MESH Headings
- Acetazolamide/therapeutic use
- Acidosis/chemically induced
- Acidosis/complications
- Acidosis/immunology
- Ammonium Chloride/therapeutic use
- Animals
- Carbonic Anhydrase Inhibitors/therapeutic use
- Carbonic Anhydrases/physiology
- Cell Differentiation/drug effects
- Contractile Proteins/biosynthesis
- Contractile Proteins/genetics
- Drug Evaluation, Preclinical
- Humans
- Hypertension, Pulmonary/drug therapy
- Hypertension, Pulmonary/enzymology
- Hypertension, Pulmonary/etiology
- Hypertension, Pulmonary/pathology
- Hypoxia/complications
- Inflammation
- Macrophages/drug effects
- Macrophages/enzymology
- Macrophages, Alveolar/drug effects
- Macrophages, Alveolar/enzymology
- Male
- Muscle, Smooth, Vascular/pathology
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/enzymology
- Protein Isoforms/antagonists & inhibitors
- Pulmonary Artery/pathology
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Rats
- Rats, Sprague-Dawley
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Christie MJ, Romano T, Murphy RM, Posterino GS. The effect of intrauterine growth restriction on Ca 2+ -activated force and contractile protein expression in the mesenteric artery of adult (6-month-old) male and female Wistar-Kyoto rats. Physiol Rep 2018; 6:e13954. [PMID: 30592188 PMCID: PMC6308111 DOI: 10.14814/phy2.13954] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 11/22/2018] [Indexed: 12/29/2022] Open
Abstract
Intrauterine growth restriction (IUGR) is known to alter vascular smooth muscle reactivity, but it is currently unknown whether these changes are driven by downstream events that lead to force development, specifically, Ca2+ -regulated activation of the contractile apparatus or a shift in contractile protein content. This study investigated the effects of IUGR on Ca2+ -activated force production, contractile protein expression, and a potential phenotypic switch in the resistance mesenteric artery of both male and female Wistar-Kyoto (WKY) rats following two different growth restriction models. Pregnant female WKY rats were randomly assigned to either a control (C; N = 9) or food restriction diet (FR; 40% of control; N = 11) at gestational day-15 or underwent a bilateral uterine vessel ligation surgery restriction (SR; N = 10) or a sham surgery control model (SC; N = 12) on day-18 of gestation. At 6-months of age, vascular responsiveness of intact mesenteric arteries was studied, before chemically permeabilization using 50 μmol/L β-escin to investigate Ca2+ -activated force. Peak responsiveness to a K+ -induced depolarization was decreased (P ≤ 0.05) due to a reduction in maximum Ca2+ -activated force (P ≤ 0.05) in both male growth restricted experimental groups. Vascular responsiveness was unchanged between female experimental groups. Segments of mesenteric artery were analyzed using Western blotting revealed IUGR reduced the relative abundance of important receptor and contractile proteins in male growth restricted rats (P ≤ 0.05), suggesting a potential phenotypic switch, whilst no changes were observed in females. Results from this study suggest that IUGR alters the mesenteric artery reactivity due to a decrease in maximum Ca2+ -activated force, and likely contributed to by a reduction in contractile protein and receptor/channel content in 6-month-old male rats, while female WKY rats appear to be protected.
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Catenaccio A, Llavero Hurtado M, Diaz P, Lamont DJ, Wishart TM, Court FA. Molecular analysis of axonal-intrinsic and glial-associated co-regulation of axon degeneration. Cell Death Dis 2017; 8:e3166. [PMID: 29120410 PMCID: PMC5775402 DOI: 10.1038/cddis.2017.489] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 08/01/2017] [Accepted: 08/17/2017] [Indexed: 12/29/2022]
Abstract
Wallerian degeneration is an active program tightly associated with axonal degeneration, required for axonal regeneration and functional recovery after nerve damage. Here we provide a functional molecular foundation for our undertstanding of the complex non-cell autonomous role of glial cells in the regulation of axonal degeneration. To shed light on the complexity of the molecular machinery governing axonal degeneration we employ a multi-model, unbiased, in vivo approach combining morphological assesment and quantitative proteomics with in silico-based higher order functional clustering to genetically uncouple the intrinsic and extrinsic processes governing Wallerian degeneration. Highlighting a pivotal role for glial cells in the early stages fragmenting the axon by a cytokinesis-like process and a cell autonomous stage of axonal disintegration associated to mitochondrial dysfunction.
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15
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Rehain-Bell K, Love A, Werner ME, MacLeod I, Yates JR, Maddox AS. A Sterile 20 Family Kinase and Its Co-factor CCM-3 Regulate Contractile Ring Proteins on Germline Intercellular Bridges. Curr Biol 2017; 27:860-867. [PMID: 28285996 DOI: 10.1016/j.cub.2017.01.058] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 12/18/2016] [Accepted: 01/27/2017] [Indexed: 11/19/2022]
Abstract
Germ cells in most animals are connected by intercellular bridges, actin-based rings that form stable cytoplasmic connections between cells promoting communication and coordination [1]. Moreover, these connections are required for fertility [1, 2]. Intercellular bridges are proposed to arise from stabilization of the cytokinetic ring during incomplete cytokinesis [1]. Paradoxically, proteins that promote closure of cytokinetic rings are enriched on stably open intercellular bridges [1, 3, 4]. Given this inconsistency, the mechanism of intercellular bridge stabilization is unclear. Here, we used the C. elegans germline as a model for identifying molecular mechanisms regulating intercellular bridges. We report that bridges are actually highly dynamic, changing size at precise times during germ cell development. We focused on the regulation of bridge stability by anillins, key regulators of cytokinetic rings and cytoplasmic bridges [1, 4-7]. We identified GCK-1, a conserved serine/threonine kinase [8], as a putative novel anillin interactor. GCK-1 works together with CCM-3, a known binding partner [9], to promote intercellular bridge stability and limit localization of both canonical anillin and non-muscle myosin II (NMM-II) to intercellular bridges. Additionally, we found that a shorter anillin, known to stabilize bridges [4, 7], also regulates NMM-II levels at bridges. Consistent with these results, negative regulators of NMM-II stabilize intercellular bridges in the Drosophila egg chamber [10, 11]. Together with our findings, this suggests that tuning of myosin levels is a conserved mechanism for the stabilization of intercellular bridges that can occur by diverse molecular mechanisms.
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16
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Cepero Malo M, Duchemin AL, Guglielmi L, Patzel E, Sel S, Auffarth GU, Carl M, Poggi L. The Zebrafish Anillin-eGFP Reporter Marks Late Dividing Retinal Precursors and Stem Cells Entering Neuronal Lineages. PLoS One 2017; 12:e0170356. [PMID: 28107513 PMCID: PMC5249142 DOI: 10.1371/journal.pone.0170356] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 01/03/2017] [Indexed: 01/09/2023] Open
Abstract
Monitoring cycling behaviours of stem and somatic cells in the living animal is a powerful tool to better understand tissue development and homeostasis. The tg(anillin:anillin-eGFP) transgenic line carries the full-length zebrafish F-actin binding protein Anillin fused to eGFP from a bacterial artificial chromosome (BAC) containing Anillin cis-regulatory sequences. Here we report the suitability of the Anillin-eGFP reporter as a direct indicator of cycling cells in the late embryonic and post-embryonic retina. We show that combining the anillin:anillin-eGFP with other transgenes such as ptf1a:dsRed and atoh7:gap-RFP allows obtaining spatial and temporal resolution of the mitotic potentials of specific retinal cell populations. This is exemplified by the analysis of the origin of the previously reported apically and non-apically dividing late committed precursors of the photoreceptor and horizontal cell layers.
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17
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Chettimada S, Joshi SR, Dhagia V, Aiezza A, Lincoln TM, Gupte R, Miano JM, Gupte SA. Vascular smooth muscle cell contractile protein expression is increased through protein kinase G-dependent and -independent pathways by glucose-6-phosphate dehydrogenase inhibition and deficiency. Am J Physiol Heart Circ Physiol 2016; 311:H904-H912. [PMID: 27521420 PMCID: PMC5114469 DOI: 10.1152/ajpheart.00335.2016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 07/06/2016] [Indexed: 11/22/2022]
Abstract
Homeostatic control of vascular smooth muscle cell (VSMC) differentiation is critical for contractile activity and regulation of blood flow. Recently, we reported that precontracted blood vessels are relaxed and the phenotype of VSMC is regulated from a synthetic to contractile state by glucose-6-phosphate dehydrogenase (G6PD) inhibition. In the current study, we investigated whether the increase in the expression of VSMC contractile proteins by inhibition and knockdown of G6PD is mediated through a protein kinase G (PKG)-dependent pathway and whether it regulates blood pressure. We found that the expression of VSMC-restricted contractile proteins, myocardin (MYOCD), and miR-1 and miR-143 are increased by G6PD inhibition or knockdown. Importantly, RNA-sequence analysis of aortic tissue from G6PD-deficient mice revealed uniform increases in VSMC-restricted genes, particularly those regulated by the MYOCD-serum response factor (SRF) switch. Conversely, expression of Krüppel-like factor 4 (KLF4) is decreased by G6PD inhibition. Interestingly, the G6PD inhibition-induced expression of miR-1 and contractile proteins was blocked by Rp-β-phenyl-1,N2-etheno-8-bromo-guanosine-3',5'-cyclic monophosphorothioate, a PKG inhibitor. On the other hand, MYOCD and miR-143 levels are increased by G6PD inhibition through a PKG-independent manner. Furthermore, blood pressure was lower in the G6PD-deficient compared with wild-type mice. Therefore, our results suggest that the expression of VSMC contractile proteins induced by G6PD inhibition occurs via PKG1α-dependent and -independent pathways.
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MESH Headings
- Animals
- Aorta/drug effects
- Aorta/metabolism
- Blotting, Western
- Cattle
- Chromatography, Liquid
- Contractile Proteins/drug effects
- Contractile Proteins/genetics
- Contractile Proteins/metabolism
- Cyclic GMP-Dependent Protein Kinase Type I/antagonists & inhibitors
- Cyclic GMP-Dependent Protein Kinase Type I/metabolism
- Cyclic GMP-Dependent Protein Kinases/antagonists & inhibitors
- Cyclic GMP-Dependent Protein Kinases/metabolism
- Gene Knockdown Techniques
- Glucosephosphate Dehydrogenase/antagonists & inhibitors
- Glucosephosphate Dehydrogenase/genetics
- Immunoprecipitation
- Kruppel-Like Factor 4
- Kruppel-Like Transcription Factors/drug effects
- Kruppel-Like Transcription Factors/genetics
- Kruppel-Like Transcription Factors/metabolism
- Mice
- MicroRNAs/drug effects
- MicroRNAs/genetics
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Nuclear Proteins/drug effects
- Nuclear Proteins/genetics
- Nuclear Proteins/metabolism
- Polymerase Chain Reaction
- Rats
- Serum Response Factor/drug effects
- Serum Response Factor/genetics
- Serum Response Factor/metabolism
- Tandem Mass Spectrometry
- Trans-Activators/drug effects
- Trans-Activators/genetics
- Trans-Activators/metabolism
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18
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Robinson MM, Dasari S, Karakelides H, Bergen HR, Nair KS. Release of skeletal muscle peptide fragments identifies individual proteins degraded during insulin deprivation in type 1 diabetic humans and mice. Am J Physiol Endocrinol Metab 2016; 311:E628-37. [PMID: 27436610 PMCID: PMC5142007 DOI: 10.1152/ajpendo.00175.2016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 07/13/2016] [Indexed: 12/16/2022]
Abstract
Insulin regulates skeletal muscle protein degradation, but the types of proteins being degraded in vivo remain to be determined due to methodological limitations. We present a method to assess the types of skeletal muscle proteins that are degraded by extracting their degradation products as low-molecular weight (LMW) peptides from muscle samples. High-resolution mass spectrometry was used to identify the original intact proteins that generated the LMW peptides, which we validated in rodents and then applied to humans. We deprived insulin from insulin-treated streptozotocin (STZ) diabetic mice for 6 and 96 h and for 8 h in type 1 diabetic humans (T1D) for comparison with insulin-treated conditions. Protein degradation was measured using activation of autophagy and proteasome pathways, stable isotope tracers, and LMW approaches. In mice, insulin deprivation activated proteasome pathways and autophagy in muscle homogenates and isolated mitochondria. Reproducibility analysis of LMW extracts revealed that ∼80% of proteins were detected consistently. As expected, insulin deprivation increased whole body protein turnover in T1D. Individual protein degradation increased with insulin deprivation, including those involved in mitochondrial function, proteome homeostasis, nDNA support, and contractile/cytoskeleton. Individual mitochondrial proteins that generated more LMW fragment with insulin deprivation included ATP synthase subunit-γ (+0.5-fold, P = 0.007) and cytochrome c oxidase subunit 6 (+0.305-fold, P = 0.03). In conclusion, identifying LMW peptide fragments offers an approach to determine the degradation of individual proteins. Insulin deprivation increases degradation of select proteins and provides insight into the regulatory role of insulin in maintaining proteome homeostasis, especially of mitochondria.
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19
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Walji TA, Turecamo SE, DeMarsilis AJ, Sakai LY, Mecham RP, Craft CS. Characterization of metabolic health in mouse models of fibrillin-1 perturbation. Matrix Biol 2016; 55:63-76. [PMID: 26902431 PMCID: PMC4992667 DOI: 10.1016/j.matbio.2016.02.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/05/2016] [Accepted: 02/05/2016] [Indexed: 11/16/2022]
Abstract
Mutations in the microfibrillar protein fibrillin-1 or the absence of its binding partner microfibril-associated glycoprotein (MAGP1) lead to increased TGFβ signaling due to an inability to sequester latent or active forms of TGFβ, respectively. Mouse models of excess TGFβ signaling display increased adiposity and predisposition to type-2 diabetes. It is therefore interesting that individuals with Marfan syndrome, a disease in which fibrillin-1 mutation leads to aberrant TGFβ signaling, typically present with extreme fat hypoplasia. The goal of this project was to characterize multiple fibrillin-1 mutant mouse strains to understand how fibrillin-1 contributes to metabolic health. The results of this study demonstrate that fibrillin-1 contributes little to lipid storage and metabolic homeostasis, which is in contrast to the obesity and metabolic changes associated with MAGP1 deficiency. MAGP1 but not fibrillin-1 mutant mice had elevated TGFβ signaling in their adipose tissue, which is consistent with the difference in obesity phenotypes. However, fibrillin-1 mutant strains and MAGP1-deficient mice all exhibit increased bone length and reduced bone mineralization which are characteristic of Marfan syndrome. Our findings suggest that Marfan-associated adipocyte hypoplasia is likely not due to microfibril-associated changes in adipose tissue, and provide evidence that MAGP1 may function independently of fibrillin in some tissues.
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20
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Hien TT, Turczyńska KM, Dahan D, Ekman M, Grossi M, Sjögren J, Nilsson J, Braun T, Boettger T, Garcia-Vaz E, Stenkula K, Swärd K, Gomez MF, Albinsson S. Elevated Glucose Levels Promote Contractile and Cytoskeletal Gene Expression in Vascular Smooth Muscle via Rho/Protein Kinase C and Actin Polymerization. J Biol Chem 2016; 291:3552-68. [PMID: 26683376 PMCID: PMC4751395 DOI: 10.1074/jbc.m115.654384] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 12/17/2015] [Indexed: 12/22/2022] Open
Abstract
Both type 1 and type 2 diabetes are associated with increased risk of cardiovascular disease. This is in part attributed to the effects of hyperglycemia on vascular endothelial and smooth muscle cells, but the underlying mechanisms are not fully understood. In diabetic animal models, hyperglycemia results in hypercontractility of vascular smooth muscle possibly due to increased activation of Rho-kinase. The aim of the present study was to investigate the regulation of contractile smooth muscle markers by glucose and to determine the signaling pathways that are activated by hyperglycemia in smooth muscle cells. Microarray, quantitative PCR, and Western blot analyses revealed that both mRNA and protein expression of contractile smooth muscle markers were increased in isolated smooth muscle cells cultured under high compared with low glucose conditions. This effect was also observed in hyperglycemic Akita mice and in diabetic patients. Elevated glucose activated the protein kinase C and Rho/Rho-kinase signaling pathways and stimulated actin polymerization. Glucose-induced expression of contractile smooth muscle markers in cultured cells could be partially or completely repressed by inhibitors of advanced glycation end products, L-type calcium channels, protein kinase C, Rho-kinase, actin polymerization, and myocardin-related transcription factors. Furthermore, genetic ablation of the miR-143/145 cluster prevented the effects of glucose on smooth muscle marker expression. In conclusion, these data demonstrate a possible link between hyperglycemia and vascular disease states associated with smooth muscle contractility.
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MESH Headings
- Actin Cytoskeleton/metabolism
- Actin Cytoskeleton/pathology
- Aged
- Animals
- Atherosclerosis/enzymology
- Atherosclerosis/metabolism
- Atherosclerosis/pathology
- Cells, Cultured
- Contractile Proteins/agonists
- Contractile Proteins/genetics
- Contractile Proteins/metabolism
- Cytoskeletal Proteins/agonists
- Cytoskeletal Proteins/genetics
- Cytoskeletal Proteins/metabolism
- Diabetes Mellitus, Type 1/complications
- Diabetes Mellitus, Type 2/complications
- Diabetic Angiopathies/enzymology
- Diabetic Angiopathies/metabolism
- Diabetic Angiopathies/pathology
- Gene Expression Regulation
- Humans
- Male
- Mice, Knockout
- Mice, Mutant Strains
- MicroRNAs/metabolism
- Muscle, Smooth, Vascular/enzymology
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Protein Kinase C/chemistry
- Protein Kinase C/metabolism
- Signal Transduction
- rho GTP-Binding Proteins/agonists
- rho GTP-Binding Proteins/metabolism
- rho-Associated Kinases/chemistry
- rho-Associated Kinases/metabolism
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21
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Vassequi-Silva T, Pereira DS, Nery Diez ACC, Braga GG, Godoy JA, Mendes CB, Dos Santos L, Krieger JE, Antunes E, Costa FTM, Vicente CP, Werneck CC. Losartan and captopril treatment rescue normal thrombus formation in microfibril associated glycoprotein-1 (MAGP1) deficient mice. Thromb Res 2015; 138:7-15. [PMID: 26826502 DOI: 10.1016/j.thromres.2015.12.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 11/10/2015] [Accepted: 12/09/2015] [Indexed: 11/18/2022]
Abstract
INTRODUCTION MAGP1 is a glycoprotein present in the elastic fibers and is a part of the microfibrils components. MAGP1 interacts with von Willebrand factor and the active form of TGF-β and BMP. In mice lacking MAGP1, thrombus formation is delayed, increasing the occlusion time of carotid artery despite presenting normal blood coagulation in vitro. MAGP1-containing microfibrils may play a role in hemostasis and thrombosis. In this work, we evaluated the function of MAGP1 and its relation to TGF-β in the arterial thrombosis process. METHODS AND RESULTS We analyzed thrombus formation time in wild type and MAGP1-deficient mice comparing Rose Bengal and Ferric Chloride induced arterial lesion. The potential participation of TGF-β in this process was accessed when we treated both wild type and MAGP1-deficient mice with losartan (an antihypertensive drug that decreases TGF-β activity) or captopril (an angiotensin converting enzyme inhibitor that was used as a control antihypertensive drug). Besides, we evaluated thrombus embolization and the gelatinolytic activity in the arterial walls in vitro and ex vivo. Losartan and captopril were able to recover the thrombus formation time without changing blood pressure, activated partial thromboplastin time (aPTT), PT (prothrombin time), platelet aggregation and adhesion, but decreased gelatinase activity. CONCLUSIONS Our results suggest that both treatments are effective in the prevention of the sub-endothelial ECM degradation, allowing the recovery of normal thrombus formation.
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22
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Brunet YR, Zoued A, Boyer F, Douzi B, Cascales E. The Type VI Secretion TssEFGK-VgrG Phage-Like Baseplate Is Recruited to the TssJLM Membrane Complex via Multiple Contacts and Serves As Assembly Platform for Tail Tube/Sheath Polymerization. PLoS Genet 2015; 11:e1005545. [PMID: 26460929 PMCID: PMC4604203 DOI: 10.1371/journal.pgen.1005545] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 08/30/2015] [Indexed: 12/21/2022] Open
Abstract
The Type VI secretion system (T6SS) is a widespread weapon dedicated to the delivery of toxin proteins into eukaryotic and prokaryotic cells. The 13 T6SS subunits assemble a cytoplasmic contractile structure anchored to the cell envelope by a membrane-spanning complex. This structure is evolutionarily, structurally and functionally related to the tail of contractile bacteriophages. In bacteriophages, the tail assembles onto a protein complex, referred to as the baseplate, that not only serves as a platform during assembly of the tube and sheath, but also triggers the contraction of the sheath. Although progress has been made in understanding T6SS assembly and function, the composition of the T6SS baseplate remains mostly unknown. Here, we report that six T6SS proteins–TssA, TssE, TssF, TssG, TssK and VgrG–are required for proper assembly of the T6SS tail tube, and a complex between VgrG, TssE,-F and-G could be isolated. In addition, we demonstrate that TssF and TssG share limited sequence homologies with known phage components, and we report the interaction network between these subunits and other baseplate and tail components. In agreement with the baseplate being the assembly platform for the tail, fluorescence microscopy analyses of functional GFP-TssF and TssK-GFP fusion proteins show that these proteins assemble stable and static clusters on which the sheath polymerizes. Finally, we show that recruitment of the baseplate to the apparatus requires initial positioning of the membrane complex and contacts between TssG and the inner membrane TssM protein. In the environment, bacteria compete for privileged access to nutrients or to a particular niche. Bacteria have therefore evolved mechanisms to eliminate competitors. Among them, the Type VI secretion system (T6SS) is a contractile machine functionally comparable to a crossbow: an inner tube is wrapped by a contractile structure. Upon contraction of this outer sheath, the inner tube is propelled towards the target cell and delivers anti-bacterial effectors. The tubular structure assembles on a protein complex called the baseplate. Here we define the composition of the baseplate, demonstrating that it is composed of five subunits: TssE, TssF, TssG, TssK and VgrG. We further detail the role of the TssF and TssG proteins by defining their localizations and identifying their partners. We show that, in addition to TssE and VgrG that have been shown to share homologies with the bacteriophage gp25 and gp27-gp5 proteins, the TssF and TssG proteins also have homologies with bacteriophage components. Finally, we show that this baseplate is recruited to the TssJLM membrane complex prior to the assembly of the contractile tail structure. This study allows a better understanding of the early events of the assembly pathway of this molecular weapon.
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23
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Lakatta EG. So! What's aging? Is cardiovascular aging a disease? J Mol Cell Cardiol 2015; 83:1-13. [PMID: 25870157 PMCID: PMC4532266 DOI: 10.1016/j.yjmcc.2015.04.005] [Citation(s) in RCA: 151] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 04/02/2015] [Accepted: 04/03/2015] [Indexed: 12/21/2022]
Abstract
"Inside every old person is a young person wondering what happened." So, what is aging? Aging is a manifestation of progressive, time-dependent failure of molecular mechanisms that create disorder within a system of DNA and its environment (nuclear, cytosolic, tissue, organ, organism, other organisms, society, terra firma, atmosphere, universe). Continuous signaling, transmitted with different kinetics across each of these environments, confers a "mutual enslavement" that creates ordered functions among the components within the system. Accrual of this molecular disorder over time, i.e. during aging, causes progressive changes in the structure and function of the heart and arteries that are quite similar in humans, non-human primates, rabbits and rats that compromise cardiovascular reserve function, and confer a marked risk for incident cardiovascular disease. Nearly all aspects of signaling within the DNA environment system within the heart and arteries become disordered with advancing age: Signals change, as does sensing of the signals, transmission of signals and responses to signals, impaired cell renewal, changes in the proteome due to alterations in genomic transcription, mRNA translation, and proteostasis. The density of some molecules becomes reduced, and post-translational modifications, e.g. oxidation and nitration phosphorylation, lead to altered misfolding and disordered molecular interactions. The stoichiometry and kinetics of enzymatic and those reactions which underlie crucial cardiac and vascular cell functions and robust reserve mechanisms that remove damaged organelles and proteins deteriorate. The CV cells generate an inflammatory defense in an attempt to limit the molecular disorder. The resultant proinflammatory milieu is not executed by "professional" inflammatory cells (i.e. white blood cells), however, but by activation of renin-angiotensin-aldosterone endothelin signaling cascades that leads to endothelial and vascular smooth muscle and cardiac cells' phenotype shifts, resulting in production of inflammatory cytokines. Progressive molecular disorder within the heart and arteries over time leads to an excessive allostatic load on the CV system, that results in an increase and "overshoot" in the inflammatory defense signaling. This age-associated molecular disorder-induced inflammation that accrues in the heart and arteries does not, itself, cause clinical signs or symptoms of CVD. Clinical signs and symptoms of these CVDs begin to emerge, however, when the age-associated inflammation in the heart and arteries exceeds a threshold. Thus, an emerging school of thought is that accelerated age-associated alterations within the heart and arteries, per se, ought to be considered to be a type of CVD, because the molecular disorder and the inflammatory milieu it creates within the heart and arteries with advancing age are the roots of the pathophysiology of most cardiovascular diseases, e.g. athersclerosis and hypertension. Because many effects of aging on the CV system can be delayed or attenuated by changes in lifestyle, e.g. diet and exercise, or by presently available drugs, e.g. those that suppress Ang II signaling, CV aging is a promising frontier in preventive cardiology that is not only ripe for, but also in dire need of attention! There is an urgency to incorporate the concept of cardiovascular aging as a disease into clinical medicine. But, sadly, the reality of the age-associated molecular disorder within the heart and ateries has, for the most part, been kept outside of mainstream clinical medicine. This article is part of a Special Issue entitled CV Aging.
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24
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Feridooni HA, Dibb KM, Howlett SE. How cardiomyocyte excitation, calcium release and contraction become altered with age. J Mol Cell Cardiol 2015; 83:62-72. [PMID: 25498213 DOI: 10.1016/j.yjmcc.2014.12.004] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 12/02/2014] [Accepted: 12/04/2014] [Indexed: 11/29/2022]
Abstract
Cardiovascular disease is the main cause of death globally, accounting for over 17 million deaths each year. As the incidence of cardiovascular disease rises markedly with age, the overall risk of cardiovascular disease is expected to increase dramatically with the aging of the population such that by 2030 it could account for over 23 million deaths per year. It is therefore vitally important to understand how the heart remodels in response to normal aging for at least two reasons: i) to understand why the aged heart is increasingly susceptible to disease; and ii) since it may be possible to modify treatment of disease in older adults if the underlying substrate upon which the disease first develops is fully understood. It is well known that age modulates cardiac function at the level of the individual cardiomyocyte. Generally, in males, aging reduces cell shortening, which is associated with a decrease in the amplitude of the systolic Ca(2+) transient. This may arise due to a decrease in peak L-type Ca(2+) current. Sarcoplasmic reticulum (SR) Ca(2+) load appears to be maintained during normal aging but evidence suggests that SR function is disrupted, such that the rate of sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA)-mediated Ca(2+) removal is reduced and the properties of SR Ca(2+) release in terms of Ca(2+) sparks are altered. Interestingly, Ca(2+) handling is modulated by age to a lesser degree in females. Here we review how cellular contraction is altered as a result of the aging process by considering expression levels and functional properties of key proteins involved in controlling intracellular Ca(2+). We consider how changes in both electrical properties and intracellular Ca(2+) handling may interact to modulate cardiomyocyte contraction. We also reflect on why cardiovascular risk may differ between the sexes by highlighting sex-specific variation in the age-associated remodeling process. This article is part of a Special Issue entitled CV Aging.
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25
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Menhofer MH, Kubisch R, Schreiner L, Zorn M, Foerster F, Mueller R, Raedler JO, Wagner E, Vollmar AM, Zahler S. The actin targeting compound Chondramide inhibits breast cancer metastasis via reduction of cellular contractility. PLoS One 2014; 9:e112542. [PMID: 25391145 PMCID: PMC4229209 DOI: 10.1371/journal.pone.0112542] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 10/07/2014] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND A major player in the process of metastasis is the actin cytoskeleton as it forms key structures in both invasion mechanisms, mesenchymal and amoeboid migration. We tested the actin binding compound Chondramide as potential anti-metastatic agent. METHODS In vivo, the effect of Chondramide on metastasis was tested employing a 4T1-Luc BALB/c mouse model. In vitro, Chondramide was tested using the highly invasive cancer cell line MDA-MB-231 in Boyden-chamber assays, fluorescent stainings, Western blot and Pull down assays. Finally, the contractility of MDA-MB-231 cells was monitored in 3D environment and analyzed via PIV analysis. RESULTS In vivo, Chondramide treatment inhibits metastasis to the lung and the migration and invasion of MDA-MB-231 cells is reduced by Chondramide in vitro. On the signaling level, RhoA activity is decreased by Chondramide accompanied by reduced MLC-2 and the stretch induced guanine nucleotide exchange factor Vav2 activation. At same conditions, EGF-receptor autophosphorylation, Akt and Erk as well as Rac1 are not affected. Finally, Chondramide treatment disrupted the actin cytoskeleton and decreased the ability of cells for contraction. CONCLUSIONS Chondramide inhibits cellular contractility and thus represents a potential inhibitor of tumor cell invasion.
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MESH Headings
- Actin Cytoskeleton/genetics
- Actin Cytoskeleton/metabolism
- Animals
- Antineoplastic Agents/pharmacology
- Breast Neoplasms/genetics
- Breast Neoplasms/metabolism
- Breast Neoplasms/pathology
- Cardiac Myosins/genetics
- Cardiac Myosins/metabolism
- Cell Line, Tumor
- Cell Movement
- Contractile Proteins/antagonists & inhibitors
- Contractile Proteins/genetics
- Contractile Proteins/metabolism
- Depsipeptides/pharmacology
- Female
- Gene Expression Regulation, Neoplastic
- Humans
- Injections, Intravenous
- Lung/drug effects
- Lung/metabolism
- Lung/pathology
- Lung Neoplasms/drug therapy
- Lung Neoplasms/genetics
- Lung Neoplasms/metabolism
- Lung Neoplasms/secondary
- Mammary Glands, Animal/drug effects
- Mammary Glands, Animal/metabolism
- Mammary Glands, Animal/pathology
- Mammary Neoplasms, Experimental/drug therapy
- Mammary Neoplasms, Experimental/genetics
- Mammary Neoplasms, Experimental/metabolism
- Mammary Neoplasms, Experimental/pathology
- Mice
- Myosin Light Chains/genetics
- Myosin Light Chains/metabolism
- Peptides, Cyclic/pharmacology
- Proto-Oncogene Proteins c-vav/genetics
- Proto-Oncogene Proteins c-vav/metabolism
- Signal Transduction
- rhoA GTP-Binding Protein/genetics
- rhoA GTP-Binding Protein/metabolism
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