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INTRODUCTION: Onset and progression of malignant tumors is a multistep process including a variety of gross chromosomal and specific genes' deregulation. Among oncogenes that are frequently altered in solid and also in hematological malignancies, the C-myc (gene locus: 8q24.21) plays a pivotal role. C-myc is a proto-oncogene encoding for a nuclear phosphoprotein implicated in cell cycle progression, apoptosis and cellular differentiation and transformation. OBJECTIVE: The purpose of the current molecular review was to explore the differences of C-myc oncogenic activity in solid and lymphoid malignancies that modify its clinical impact on them. MATERIAL AND METHOD: A systematic review of the literature in the international database PubMed was carried out. The year 2010 was set as a prominent time limit for the publication date of articles in the majority of them, whereas specific references of great importance and historical value in the field of C-myc gene discovery and analysis were also included. The following keywords were used: C-myc, oncogene, signaling pathway, malignancies, carcinoma, lymphoma. A pool of 43 important articles were selected for the present study at the basis of combining molecular knowledge with new targeted therapeutic strategies. RESULTS: C-myc oncogene demonstrates two different mechanisms of deregulation: amplification, mutation and translocation patterns. These particular aspects of gene alteration are unique for solid and non-solid (hematological) malignancies, respectively. CONCLUSIONS: C-myc is characterized by diversity regarding its deregulation mechanisms in malignancies derived from different tissues. C-myc translocation is sporadically combined with amplification ("complicon" formation) or mutations creating exotic genetic signatures. This "bi-phasic" C-myc deregulation model in the corresponding malignant tumor categories clinically affects the corresponding patients, also modifying the targeted therapeutic strategies on them.
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INTRODUCTION: Coronary artery disease (CAD) is a major and multifaceted health problem but also the first cause of death in modern Western societies. Furthermore, myocardial infarction (MI) constitutes a challenge for analysis in the field of molecular mechanisms, early diagnosis and therapeutic approaches, as its incidence increases every year worldwide. Concerning the histopathological diagnosis in the corresponding cases, a variety of immunohistochemistry (IHC) markers and methods are available to support conventional histology diagnosis. Immunohistochemistry techniques are effective for use in forensic pathology, expanding the limits of differential diagnoses in borderline cases, as they can be applied to tissue samples fixed in formalin and embedded in paraffin. OBJECTIVE: The purpose of the current review was to explore the role of connexin 43 (gene locus: 6q22.31) as a reliable biomarker of myocardial disease/infarction and its impact on MI pathology. MATERIAL AND METHOD: A systematic review of the literature was carried out based on the international database PubMed. The majority of medical data referred to articles published after the year 2020, whereas specific references of great importance and value were also included. The following keywords were used: coronary, artery, myocardial, infarction, connexin and immunohistochemistry. RESULTS: A pool of 38 significant articles focused on the mechanisms and novel experimental biomarkers was selected for the present study at the basis of combining molecular knowledge with new clinical features in CAD, and MI histodiagnosis. CONCLUSIONS: The role of connexin 43 - as a significant gap junction intermediate protein - in MI pathology, clinical symptoms and prognosis is critical because its dysfunction is involved in myocardial conduction and the onset of ventricular arrhythmias due to a crucial interruption of the intra-cardiomyocyte's conjunction.
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Among the tumour suppressor genes that affect critically cell functions and homeostasis, phosphatase and tensin homolog deleted in chromosome 10 (PTEN- gene locus: 10q21) regulates the PI3K/Akt/mTOR signalling pathway. PTEN is deleted, mutated or epigenetically hyper-methylated in a variety of human solid malignancies. Salivary gland carcinomas (SGCs) belong to the head and neck carcinomas (HNCs) super category of solid malignancies. Histo-pathologically, they demonstrate a significant diversity due to a variety of distinct and mixed subtypes. Genetically, they are characterized by a broad spectrum of gene and chromosomal imbalances. Referring specifically to suppressor genes, PTEN deregulation plays a critical role in signaling transduction in the corresponding SGC pre- and malignant epithelia modifying the response rates to potential targeted therapeutic strategies. In the current review, we explored the role of PTEN deregulation mechanisms that are involved in the onset and progression of SGCs.
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DNA mismatch repair system (MMR) is considered a leading genetic mechanism in stabilizing DNA structure and maintaining its function. DNA MMR is a highly conserved system in bacteria, prokaryotic, and eukaryotic cells, and provides the highest protection to DNA by repairing micro-structural alterations. DNA MMR proteins are involved in the detection and repair of intra-nucleotide base-to-base errors inside the complementary DNA strand recognizing the recently synthesized strand from the parental template. During DNA replication, a spectrum of errors including base insertion, deletion, and miss-incorporation negatively affect the molecule's structure and its functional stability. A broad spectrum of genomic alterations such as promoter hyper methylation, mutation, and loss of heterozygosity (LOH) in MMR genes including predominantly hMLH1, hMSH2, hMSH3, hMSH6, hPMS1, and hPMS2 lead to their loss of base-to-base error repairing procedure. Microsatellite instability (MSI) refers to the DNA MMR gene alterations that are observed in a variety of malignancies of different histological origins. In the current review, we present the role of DNA MMR deficiency in breast adenocarcinoma, a leading cancer-based cause of death in females worldwide.
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Breast adenocarcinoma is a leading cause of death in females worldwide. A broad spectrum of genetic and epigenetic alterations has been already identified and reported in millions of examined cancerous substrates, evidence of a high-level genomic heterogeneity that characterizes these malignancies. Concerning epigenetic changes and imbalances that critically affect progression and prognosis in the corresponding patients, DNA methylation, histone modifications (acetylation), micro-RNAs (miRs) alterations and chromatin re-organization represent the main mechanisms. Referring to DNA methylation, promoter hyper-hypo methylation in critical tumour suppressor and oncogenes is implicated in normal epithelia transformation to their neoplastic and finally malignant cyto-phenotypes. The current review is focused on the different methylation patterns and mechanisms detected in breast adenocarcinoma and their impact on the corresponding groups of patient response to specific chemotherapeutic regimens and life span prognosis.
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Short-term synaptic plasticity represents a fundamental mechanism in neural information processing and is regulated by neuromodulators. Here, using field recordings from the CA1 region of adult rat hippocampal slices, we show that excitatory synaptic transmission is suppressed by strong but not moderate activation of adenosine A1 receptors by 2-Chloro-N6-cyclopentyladenosine (CCPA) more in the dorsal than the ventral hippocampus; in contrast, both mild and strong activation of GABAB receptors by baclofen (1 µM, 10 µM) suppress synaptic transmission more in the ventral than the dorsal hippocampus. Using a 10-pulse stimulation train of variable frequency, we found that CCPA modulates short-term synaptic plasticity independently of the suppression of synaptic transmission in both segments of the hippocampus and at stimulation frequencies greater than 10 Hz. However, specifically regarding the paired-pulse ratio (PPR) and frequency facilitation/depression (FF/D) we found significant drug action before but not after adjusting conditioning responses to control levels. Activation of GABABRs by baclofen suppressed synaptic transmission more in the ventral than the dorsal hippocampus. Furthermore, relatively high (10 µM) but not low (1 µM) baclofen concentration enhanced both PPR and FF in both hippocampal segments at stimulation frequencies greater than 1 Hz, independently of the suppression of synaptic transmission by baclofen. These results show that A1Rs and GABABRs control synaptic transmission more effectively in the dorsal and the ventral hippocampus, respectively, and suggest that these receptors modulate PPR and FF/D at different frequency bands of afferent input, in both segments of the hippocampus.
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PURPOSE: The role of angiogenic factors -such as vascular endothelial growth factor (VEGF) - in the development and progression of pterygia lesions remains under investigation. In the current study, we analyzed VEGF protein expression in a series of pterygia and normal conjunctiva epithelia. METHODS: Using a liquid-based cytology assay, thirty (n = 30) cell specimens were obtained by applying a smooth scraping on conjunctiva epithelia and fixed accordingly. None of them had a history of Human Papillomavirus (HPV) infection. Similarly, the same process was applied also in normal conjunctiva epithelia (n = 10; control group). We constructed five (n = 5) slides each containing eight (n = 8) cell spots. An immunocytochemistry (ICC) assay was implemented. Digital image analysis was also performed for evaluating objectively the corresponding immunostaining intensity levels. RESULTS: All the examined pterygia cell samples over-expressed the marker. High staining intensity levels were detected in 15/30 (50%), whereas the rest 15/30 (50%) demonstrated moderate expression. Overall VEGF expression was statistically significantly higher in pterygia compared to normal conjunctiva epithelia (p=.0001). Concerning the other parameters, VEGF protein expression did not associate with the gender of the patients (p = 0.518), the presence of a recurrent lesion (p = 0.311), the anatomical location (p = 0.191) or with their morphology (p = 0.316). Interestingly, the recurrent lesions demonstrated the highest levels of VEGF expression. CONCLUSIONS: VEGF overexpression is a frequent event in pterygia playing a potentially central molecular role in the progression of the lesion. Cell spot array analysis -based on liquid cytology- seems to be an innovative, easy-to-use technique for analyzing a broad variety of molecules in multiple specimens on the same slide by applying different ICC assays.
Subject(s)
Conjunctiva , Pterygium , Vascular Endothelial Growth Factor A , Alphapapillomavirus , Conjunctiva/abnormalities , Conjunctiva/metabolism , Conjunctiva/pathology , Conjunctiva/virology , Humans , Papillomaviridae/metabolism , Pterygium/diagnosis , Pterygium/metabolism , Pterygium/virology , Vascular Endothelial Growth Factor A/biosynthesisABSTRACT
Chronic and acute respiratory diseases pose a major problem for public health worldwide due to the high morbidity and mortality rates, while treatment options remain mostly symptomatic. The renin-angiotensin system (RAS) plays an important role in lung tissue, regulating pulmonary circulation and blood pressure, but also contributing to normal pulmonary function and development. Angiotensin-converting enzyme (ACE) and its homologous angiotensin-converting enzyme 2 (ACE2) are considered to be amongst the main RAS regulators and are highly expressed in the pulmonary vascular endothelium. This review discusses the impact of ACE and ACE2 functional gene polymorphisms on seven major pulmonary diseases, in terms of predisposition, course, and outcome, revealing their potential utility as both genetic markers and biomarkers. The discussed conditions include chronic obstructive pulmonary disease (COPD), pulmonary hypertension (PH), asthma, acute lung injury (ALI), acute respiratory distress syndrome (ARDS), lung cancer and pulmonary sarcoidosis (PS), as well as SARS-CoV-2 viral infection and COVID-19 disease.
Subject(s)
Angiotensin-Converting Enzyme 2 , COVID-19 , Peptidyl-Dipeptidase A , Humans , Peptidyl-Dipeptidase A/genetics , Polymorphism, Genetic , Renin-Angiotensin System/genetics , SARS-CoV-2ABSTRACT
Coronavirus-related Severe Acute Respiratory Syndrome (SARS-CoV) in 2002/2003, Middle-East Respiratory Syndrome (MERS-Cov) in 2012/2013, and especially the current 2019/2020 Severe Acute Respiratory Syndrome-2 (SARS-CoV-2) tested the national health systems' endurance worldwide. In order to fight this emergency situation, a variety of pharmaceutical companies focused on the design and development of efficient vaccines that are considered necessary for providing a level of normalization in totally affected human social-economical activity worldwide. COVID-19 led to an increased uncertainty in the field of oncological patients' management disrupting the normal conditions of therapeutic and monitoring procedures. In the current article, we explored the impact of SARS-CoV-2 infection on oral carcinoma patients. We observed COVD-19 pandemic negatively affects the normality regarding early diagnosis and optimal management (surgical operation, post-operational follow up/monitoring) in HNSCC/OSCC patients. Understanding the involvement of SARS-CoV-2 in the progression of malignancies is the first critical step for targeting the virus by efficient monoclonal antibodies and vaccines.
Subject(s)
COVID-19/complications , Mouth Neoplasms/pathology , SARS-CoV-2/isolation & purification , COVID-19/transmission , COVID-19/virology , Disease Management , Humans , Mouth Neoplasms/epidemiology , Mouth Neoplasms/therapy , Mouth Neoplasms/virologyABSTRACT
Sexually transmitted diseases (STDs) affect mainly young individuals and cause health, social, and economic problems worldwide. The present study used a web questionnaire to assess the awareness, knowledge, sexual behaviors, and common practices regarding STDs in young Greek adults. The 1833 individuals, aged 18-30 years, who responded to the study seem to be particularly knowledgeable regarding STDs such as AIDS (97.7%), warts (97%), Chlamydia (92.2%), genital herpes (89.9%), syphilis (81.9%), and gonorrhea (72.1%), whereas lower percentages were noted for trichomoniasis (39.3%), Molluscum contagiosum (12.9%), mycoplasmosis (11.6%), and amoebiasis (7.4%). Regarding oral STD transmission, participants replied correctly for genital herpes (45%), warts (35.8%), and AIDS (HIV; 33.8%), whereas 30.2% were unfamiliar with oral sexual transmission. Of the participants, 52% were not aware that STDs might cause infertility. Only 40.4% of the respondents reported always using condoms during sexual intercourse, and 48.6% had never been tested for STDs. The majority of the young population (55%) presented a moderate knowledge STD score (41-60%) and was associated with demographic parameters such as age, gender, sexual preference, number of sexual partners, and residence (p < 0.05). These findings provide important information regarding the prevention of STDs and highlight the significance of developing more effective sex education programs for young people in Greece.
Subject(s)
Gonorrhea , Sexually Transmitted Diseases , Adolescent , Adult , Condoms , Greece/epidemiology , Humans , Sexual Behavior , Sexually Transmitted Diseases/epidemiologyABSTRACT
Gross chromosomal and specific gene alterations are genetic aspects that are involved in rise, progression, and metastatic expansion of malignances. Concerning Uveal melanoma (UM), a variety of chromosome and gene functional and numerical imbalances in crucial molecular pathways such as cell cycle regulation, signaling transduction, apoptosis or angiogenesis have been identified and explained. UM is the most common primary ocular malignancy demonstrating increased rates, especially in middle-aged white (Caucasian) populations. Chronic exposure to ultraviolet rays/sunlight, race, gender (males), or some familial hereditary syndrome in sub-groups of patients are major factors correlated to increased risk for UM rise and progression. Specific genetic signatures at the level of chromosomal instability (CI) or at the gene mutations status characterize sub-groups of patients affecting the biological behaviour of the tumour leading to aggressive phenotypes (advanced stage-distant metastases, poor response, and survival rates). Sporadic or hereditary mediated mutations in genes including BAP1, EIF1AX, GNA11, GNAQ CHEK2, PALB2, SMARCE1, MBD4, MSH6 and MLH1. In the current molecular review, we present specific mutations -as a landscape- that are implicated in UM genetic substrate and create a variety of genetic signatures in the corresponding patients.
Subject(s)
Melanoma/genetics , Mutation , Uveal Neoplasms/genetics , HumansABSTRACT
PURPOSE: The concurrent prevalence investigation of human papillomavirus (HPV), Mycoplasma hominis (Mh) and Ureaplasma urealyticum (Uu) in women in order to estimate the association of co-infection with cervical lesions. METHODS: The study cohort comprised 120 women with no cervical lesions (control group) and 62 women with abnormal cytological findings from the cervix (cervical intraepithelial lesion/neoplasia) as study group. A combination of molecular analyses was implemented. RESULTS: The presence of HPV infection was shown in 52/62 (83.9%) of women with abnormal cytology. Women with cervix cytological findings were shown to have 17.6 times higher risk for Mh and Uu co-infection (p=0.001). HPV and Uu co-infection were detected with a higher prevalence among women with CIN 3 and invasive cancer. CONCLUSION: These findings are consistent with the notion that microbial co-infections may play an important role in persistent inflammation and progression of cervical lesions.
Subject(s)
Carcinoma/complications , Coinfection/epidemiology , Mycoplasmataceae , Mycoplasmatales Infections/complications , Papillomavirus Infections/complications , Uterine Cervical Dysplasia/complications , Uterine Cervical Neoplasms/complications , Adolescent , Adult , Aged , Cohort Studies , Female , Humans , Middle Aged , Young AdultABSTRACT
Idiopathic pregnancy complications pose a major threat to both maternal and fetal health worldwide. Numerous studies have implicated the role of the renin-angiotensin system (RAS) in the development of obstetric syndromes, since it is crucial for the uteroplacental function. A major RAS component is the angiotensin-converting enzyme (ACE), which hydrolyses angiotensin I to angiotensin II, and not only regulates arterial pressure, but also fibrinolytic activity, indirectly, through the expression of plasminogen activator inhibitor-1. A key functional polymorphism of the ACE gene is the insertion/deletion (I/D) polymorphism, which affects gene expression and product levels, and can therefore lead to high blood pressure and/or reduced fibrinolytic activity. These can cause major pregnancy complications, such as preeclampsia, recurrent pregnancy loss and preterm birth. This review discusses how the ACE I/D is associated with susceptibility towards pregnancy complications, on its own or in combination with other functional gene polymorphisms such, as the angiotensin II receptor type 1 (AT1R) A1166CC, angiotensin II receptor type 2 (AT2R) G1332A, plasminogen activator inhibitor-1 (PAI-1) 4G/5G, matrix metallopeptidase-9 (MMP-9) C1562T, angiotensinogen (AGT) M235T, renin (REN) 83A/G, factor XIII (F13) Val34Leu and endothelial nitric oxide synthase (eNOS) 4a/b.
Subject(s)
Pre-Eclampsia , Premature Birth , Female , Genotype , Humans , Infant, Newborn , Peptidyl-Dipeptidase A/genetics , Polymorphism, Genetic , Pre-Eclampsia/genetics , Pregnancy , Renin-Angiotensin System/genetics , Risk FactorsABSTRACT
BACKGROUND/AIM: Oral squamous cell carcinoma (OSCC) demonstrates aggressive biological behavior in subgroups of patients with specific molecular characteristics. Concerning metastatic potential, disruption of cell to cell adhesion is a critical event in epithelial malignancies including OSCC. Our aim was to investigate the role of E-Cadherin expression in OSCC patients as a valuable protein marker. MATERIALS AND METHODS: Fifty (n=50) tissue sections derived from primary OSCCs were analyzed by implementing an immunohistochemistry (IHC) assay based on a proper anti-E-cadherin antibody. Digital image analysis was also implemented for an objective evaluation of the corresponding protein expression levels. RESULTS: E-cadherin altered expression (low to negative) was observed in 34/50 (68%) cases, whereas the rest (16/50-32%) demonstrated normal (high to moderate) expression. E-Cadherin abnormal expressionwas associated with the stage of the examined malignancies (p=0.023), whereas no significant correlations with grade, gender, smoking status or human papilloma virus (HPV) history were observed. CONCLUSION: E-Cadherin down regulation is frequently observed in OSCC and is correlated to a progressively aggressive phenotype of the malignancy in the corresponding patients (advanced stage), but it seems that the impact of HPV persistent infection on these patients is not a critical parameter.
Subject(s)
Alphapapillomavirus , Cadherins/genetics , Carcinoma, Squamous Cell/etiology , Gene Expression , Mouth Neoplasms/etiology , Papillomavirus Infections/complications , Biomarkers, Tumor , Cadherins/metabolism , Carcinoma, Squamous Cell/metabolism , Carcinoma, Squamous Cell/pathology , Disease Susceptibility , Female , Humans , Immunohistochemistry , Male , Mouth Neoplasms/metabolism , Mouth Neoplasms/pathology , Neoplasm Grading , Neoplasm Staging , Papillomavirus Infections/virologyABSTRACT
The glycome undergoes characteristic changes during histogenesis and organogenesis, but our understanding of the importance of select glycan structures for tissue formation and homeostasis is incomplete. Here, we present a human organotypic platform that allows genetic dissection of cellular glycosylation capacities and systematic interrogation of the roles of distinct glycan types in tissue formation. We used CRISPR-Cas9 gene targeting to generate a library of 3D organotypic skin tissues that selectively differ in their capacity to produce glycan structures on the main types of N- and O-linked glycoproteins and glycolipids. This tissue library revealed distinct changes in skin formation associated with a loss of features for all tested glycoconjugates. The organotypic skin model provides phenotypic cues for the distinct functions of glycoconjugates and serves as a unique resource for further genetic dissection and identification of the specific structural features involved. The strategy is also applicable to other organotypic tissue models.
Subject(s)
CRISPR-Cas Systems/genetics , Clustered Regularly Interspaced Short Palindromic Repeats/genetics , Epithelium/physiology , Polysaccharides/genetics , Gene Library , Glycoproteins/genetics , Glycosylation , Humans , Skin/metabolism , Skin/pathologyABSTRACT
We performed a survey aimed at analyzing milk samples collected from cows with mastitis for the presence of extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli. Single-quarter mastitic milk samples obtained from 400 cows in 23 Greek dairy herds with a history of E. coli mastitis were processed for the selective isolation of ESBL-producing E. coli. The antimicrobial susceptibility of the ESBL-producing isolates was analyzed using agar disk diffusion, and minimum inhibitory concentrations of colistin were determined by broth microdilution. We used PCR followed by DNA sequencing to characterize the ß-lactamases and mcr-1 (colistin resistance) genes, and for phylotyping and multilocus sequence typing. We found a total of 89/400 (22.25%) E. coli isolates from 12/23 (52%) farms. Six isolates originating from 6 cows on a single farm were ESBL producers and were resistant to cefquinome, amoxicillin-clavulanic acid, aztreonam, ampicillin, and colistin. Five of these isolates were resistant to trimethoprim-sulfamethoxazole, and 5 to streptomycin. The 6 ESBL producers were mcr-1-positive and carried blaTEM-1 genes; 3 also carried blaCTX-M genes, and 3 carried blaSHV genes. All of the ESBL producers belonged to phylogroup A, multilocus sequence type ST666 (n = 5), or a single locus variant of ST666 (n = 1). To our knowledge, this is the first report of endemic bovine mastitis caused by mcr-1-positive, ESBL-producing E. coli. These results highlight the value of active surveillance of antimicrobial resistance not commonly tested by diagnostic laboratories for the early detection of novel resistant strains.
Subject(s)
Colistin/pharmacology , Escherichia coli Infections/veterinary , Escherichia coli/isolation & purification , Mastitis, Bovine/microbiology , Animals , Anti-Bacterial Agents/pharmacology , Cattle , Cephalosporins/pharmacology , Dairying , Drug Resistance, Bacterial , Escherichia coli/drug effects , Escherichia coli/enzymology , Escherichia coli/genetics , Escherichia coli Infections/microbiology , Escherichia coli Proteins/biosynthesis , Farms , Female , Greece , Microbial Sensitivity Tests , Milk , Multilocus Sequence Typing , beta-Lactamases/biosynthesis , beta-Lactamases/geneticsABSTRACT
BACKGROUND AND OBJECTIVE: The role of vascular endothelial growth factor (VEGF)-A in the resolution of ventilator-associated pneumonia (VAP) was investigated in clinical and mouse pneumonia models. METHODS: VEGF-A was measured for seven consecutive days by an immunosorbent assay in sera of 82 patients with VAP and changes from baseline were correlated with the resolution of VAP. Experimental animals were challenged intratracheally with Pseudomonas aeruginosa. Mouse bronchoalveolar lavage (BAL) samples and segments of lung tissue were obtained at 24, 48 and 124 h after bacterial challenge. Levels of VEGF-A, tumour Necrosis Factor alpha (TNF-α), interleukin (IL)-1ß, interferon-gamma (IFNγ) and myeloperoxidase (MPO) activity were measured in these samples. RESULTS: VAP resolved in 36.1% of patients with a less than 45% increase of VEGF-A on day 5 compared to 65.2% of patients with a more than 45% increase (P = 0.014). This was also accompanied by an earlier resolution of VAP (log-rank: 7.99; P = 0.005) and it was not pathogen-specific. The increase of VEGF-A was an independent variable associated with VAP resolution in forward logistic regression analysis where Acute Physiology and Chronic Health Evaluation (APACHE) II and Sequential Organ Failure Assessment (SOFA) scores were included as independent variables. VEGF-A in mouse BAL and lung tissue increased significantly at 124 h but not with the other mediators. In mice pre-treated with bevacizumab, VEGF-A concentrations decreased while TNF-α and MPO significantly increased. CONCLUSION: In patients, an association between increased levels of circulating VEGF-A and VAP resolution was observed. The mouse study suggests that elevated VEGF-A levels may be associated with lung inflammation resolution. CLINICAL TRIAL REGISTRATION: NCT00297674 at www.clinicaltrials.gov.
Subject(s)
Pneumonia, Bacterial/metabolism , Pneumonia, Ventilator-Associated/blood , Pseudomonas Infections/metabolism , Pseudomonas aeruginosa , Vascular Endothelial Growth Factor A/blood , Vascular Endothelial Growth Factor A/metabolism , APACHE , Animals , Anti-Bacterial Agents/therapeutic use , Biomarkers/blood , Bronchoalveolar Lavage Fluid/chemistry , Clarithromycin/therapeutic use , Double-Blind Method , Humans , Interferon-gamma/metabolism , Interleukin-1beta/metabolism , Mice , Peroxidase/metabolism , Pneumonia, Bacterial/microbiology , Pneumonia, Ventilator-Associated/drug therapy , Prospective Studies , Time Factors , Tumor Necrosis Factor-alpha/metabolismABSTRACT
Mesenchymal stem cells (MSC) are suggested to be important progenitors of myofibroblasts in fibrosis. To understand the role of Rho GTPase signaling in TGFß-induced myofibroblast differentiation of MSC, we generated a novel MSC line and its descendants lacking functional Rho GTPases and Rho GTPase signaling components. Unexpectedly, our data revealed that Rho GTPase signaling is required for TGFß-induced expression of α-smooth muscle actin (αSMA) but not of collagen I α1 (col1a1). Whereas loss of RhoA and Cdc42 reduced αSMA expression, ablation of the Rac1 gene had the opposite effect. Although actin polymerization and MRTFa were crucial for TGFß-induced αSMA expression, neither Arp2/3-dependent actin polymerization nor cofilin-dependent severing and depolymerization of F-actin were required. Instead, F-actin levels were dependent on cell contraction, and TGFß-induced actin polymerization correlated with increased cell contraction mediated by RhoA and Cdc42. Finally, we observed impaired collagen I secretion in MSC lacking RhoA or Cdc42. These data give novel molecular insights into the role of Rho GTPases in TGFß signaling and have implications for our understanding of MSC function in fibrosis.