Essential Bromodomain TcBDF2 as a Drug Target against Chagas Disease

Trypanosoma cruzi is a unicellular parasite that causes Chagas disease, which is endemic in the American continent but also worldwide, distributed by migratory movements. A striking feature of trypanosomatids is the polycistronic transcription associated with post-transcriptional mechanisms that regulate the levels of translatable mRNA. In this context, epigenetic regulatory mechanisms have been revealed to be of great importance, since they are the only ones that would control the access of RNA polymerases to chromatin. Bromodomains are epigenetic protein readers that recognize and specifically bind to acetylated lysine residues, mostly at histone proteins. There are seven coding sequences for BD-containing proteins in trypanosomatids, named TcBDF1 to TcBDF7, and a putative new protein containing a bromodomain was recently described. Using the Tet-regulated overexpression plasmid pTcINDEX-GW and CRISPR/Cas9 genome editing, we were able to demonstrate the essentiality of TcBDF2 in T. cruzi. This bromodomain is located in the nucleus, through a bipartite nuclear localization signal. TcBDF2 was shown to be important for host cell invasion, amastigote replication, and differentiation from amastigotes to trypomastigotes. Overexpression of TcBDF2 diminished epimastigote replication. Also, some processes involved in pathogenesis were altered in these parasites, such as infection of mammalian cells, replication of amastigotes, and the number of trypomastigotes released from host cells. In in vitro studies, TcBDF2 was also able to bind inhibitors showing a specificity profile different from that of the previously characterized TcBDF3. These results point to TcBDF2 as a druggable target against T. cruzi.

Alpha-Tubulin Acetylation in Trypanosoma cruzi: A Dynamic Instability of Microtubules Is Required for Replication and Cell Cycle Progression

Trypanosomatids have a cytoskeleton arrangement that is simpler than what is found in most eukaryotic cells. However, it is precisely organized and constituted by stable microtubules. Such microtubules compose the mitotic spindle during mitosis, the basal body, the flagellar axoneme and the subpellicular microtubules, which are connected to each other and also to the plasma membrane forming a helical arrangement along the central axis of the parasite cell body. Subpellicular, mitotic and axonemal microtubules are extensively acetylated in Trypanosoma cruzi. Acetylation on lysine (K) 40 of α-tubulin is conserved from lower eukaryotes to mammals and is associated with microtubule stability. It is also known that K40 acetylation occurs significantly on flagella, centrioles, cilia, basal body and the mitotic spindle in eukaryotes. Several tubulin posttranslational modifications, including acetylation of K40, have been cataloged in trypanosomatids, but the functional importance of these modifications for microtubule dynamics and parasite biology remains largely undefined. The primary tubulin acetyltransferase was recently identified in several eukaryotes as Mec-17/ATAT, a Gcn5-related N-acetyltransferase. Here, we report that T. cruzi ATAT acetylates α-tubulin in vivo and is capable of auto-acetylation. TcATAT is located in the cytoskeleton and flagella of epimastigotes and colocalizes with acetylated α-tubulin in these structures. We have expressed TcATAT with an HA tag using the inducible vector pTcINDEX-GW in T. cruzi. Over-expression of TcATAT causes increased levels of the alpha tubulin acetylated species, induces morphological and ultrastructural defects, especially in the mitochondrion, and causes a halt in the cell cycle progression of epimastigotes, which is related to an impairment of the kinetoplast division. Finally, as a result of TcATAT over-expression we observed that parasites became more resistant to microtubule depolymerizing drugs. These results support the idea that α-tubulin acetylation levels are finely regulated for the normal progression of T. cruzi cell cycle.

Through the eyes of a pathogen: light perception and signal transduction in Acinetobacter baumannii

Sunlight is a ubiquitous environmental stimulus for the great majority of living organisms on Earth; therefore it is logical to expect the development of "seeing mechanisms" which lead them to successfully adapt to particular ecological niches. Although these mechanisms were recognized in photosynthetic organisms, it was not until recent years that the scientific community found out about light perception in chemotrophic ones. In this review we summarize the current knowledge about the mechanism of light sensing through the blue light receptor BlsA in Acinetobacter baumannii. We highlight its function as a global regulator that pleiotropically modulates a large number of physiological processes, many of which are linked to the ability of this opportunist pathogen to persist in adverse intrahospital environments. Moreover, we describe with some specific examples the molecular basis of how this photoregulator senses blue light and translates this physical signal by modulating gene expression of target regulons. Finally, we discuss the possible course of these investigations needed to dissect this complex regulatory network, which ultimately will help us better understand the A. baumannii physiology.

Doppler Echocardiographic Assessment of Left Ventricular Diastolic Function in Patients with Primary Lung Cancer Treated with Doxorubicin

Eighteen patients were examined by Doppler echocardiography before and after treatment with doxorubicin (DXR). Early left ventricular filling rate decreased from 66±15 to 51±10 cm/sec whereas late filling rate increased from 48±12 to 61±9 cm/sec (p < 0.05) with inversion of the E/A ratio suggesting an impairment of left ventricular diastolic function; conversely no significant changes were found in systolic function indexes. These results suggest that follow-up of patients treated with DXR must include left ventricular diastolic function studies. Doppler echocardiography can be successfully used to detect the presence of diastolic abnormalities.

A novel peptidoglycan D,L-endopeptidase induced by Salmonella inside eukaryotic cells contributes to virulence

Bacteria remodel peptidoglycan structure in response to environmental changes. Many enzymes are involved in peptidoglycan metabolism; however, little is known about their responsiveness in a defined environment or the modes they assist bacteria to adapt to new niches. Here, we focused in peptidoglycan enzymes that intracellular bacterial pathogens use inside eukaryotic cells. We identified a peptidoglycan enzyme induced by Salmonella enterica serovar Typhimurium in fibroblasts and epithelial cells. This enzyme, which shows γ-D-glutamyl-meso-diaminopimelic acid D,L-endopeptidase activity, is also produced by the pathogen in media with limited nutrients and in resting conditions. The enzyme, termed EcgA for endopeptidase responding to cessation of growth', is encoded in a S. Typhimurium genomic island absent in Escherichia coli. EcgA production is strictly dependent on the virulence regulator PhoP in extra- and intracellular environments. Consistent to this regulation, a mutant lacking EcgA is attenuated in the mouse typhoid model. These findings suggest that specialised peptidoglycan enzymes, such as EcgA, might facilitate Salmonella adaptation to the intracellular lifestyle. Moreover, they indicate that readjustment of peptidoglycan metabolism inside the eukaryotic cell is essential for host colonisation.

New evidence for differential roles of l10 ribosomal proteins from Arabidopsis

The RIBOSOMAL PROTEIN L10 (RPL10) is an integral component of the eukaryotic ribosome large subunit. Besides being a constituent of ribosomes and participating in protein translation, additional extraribosomal functions in the nucleus have been described for RPL10 in different organisms. Previously, we demonstrated that Arabidopsis (Arabidopsis thaliana) RPL10 genes are involved in development and translation under ultraviolet B (UV-B) stress. In this work, transgenic plants expressing ProRPL10:β-glucuronidase fusions show that, while AtRPL10A and AtRPL10B are expressed both in the female and male reproductive organs, AtRPL10C expression is restricted to pollen grains. Moreover, the characterization of double rpl10 mutants indicates that the three AtRPL10s differentially contribute to the total RPL10 activity in the male gametophyte. All three AtRPL10 proteins mainly accumulate in the cytosol but also in the nucleus, suggesting extraribosomal functions. After UV-B treatment, only AtRPL10B localization increases in the nuclei. We also here demonstrate that the three AtRPL10 genes can complement a yeast RPL10 mutant. Finally, the involvement of RPL10B and RPL10C in UV-B responses was analyzed by two-dimensional gels followed by mass spectrometry. Overall, our data provide new evidence about the nonredundant roles of RPL10 proteins in Arabidopsis.

Plant L10 ribosomal proteins have different roles during development and translation under ultraviolet-B stress

Ribosomal protein L10 (RPL10) proteins are ubiquitous in the plant kingdom. Arabidopsis (Arabidopsis thaliana) has three RPL10 genes encoding RPL10A to RPL10C proteins, while two genes are present in the maize (Zea mays) genome (rpl10-1 and rpl10-2). Maize and Arabidopsis RPL10s are tissue-specific and developmentally regulated, showing high levels of expression in tissues with active cell division. Coimmunoprecipitation experiments indicate that RPL10s in Arabidopsis associate with translation proteins, demonstrating that it is a component of the 80S ribosome. Previously, ultraviolet-B (UV-B) exposure was shown to increase the expression of a number of maize ribosomal protein genes, including rpl10. In this work, we demonstrate that maize rpl10 genes are induced by UV-B while Arabidopsis RPL10s are differentially regulated by this radiation: RPL10A is not UV-B regulated, RPL10B is down-regulated, while RPL10C is up-regulated by UV-B in all organs studied. Characterization of Arabidopsis T-DNA insertional mutants indicates that RPL10 genes are not functionally equivalent. rpl10A and rpl10B mutant plants show different phenotypes: knockout rpl10A mutants are lethal, rpl10A heterozygous plants are deficient in translation under UV-B conditions, and knockdown homozygous rpl10B mutants show abnormal growth. Based on the results described here, RPL10 genes are not redundant and participate in development and translation under UV-B stress.

An observational study on the epidemiology of respiratory tract bacterial pathogens and their susceptibility to four injectable beta-lactam antibiotics: piperacillin, piperacillin/tazobactam, ceftazidime and ceftriaxone

Bacterial infections of the respiratory tract account for a large proportion of total medical consultations in general practice. In recent years, antibiotic resistance has increased alarmingly in a number of bacterial species that are common causes of these infections. The aim of this observational study was to determine the antibiotic resistance of microbial agents isolated from patients with acute or acutely exacerbated respiratory infections. Subjects recruited as potential sources of bacteria were either outpatients seen in a number of specialized clinics and hospital practices, or hospitalized patients. Overall, 648 consecutive patients (67% male, mean age 48.1+/-27.0 years) with infection of the upper or lower respiratory tract were observed during a 13-month period. A total of 551 pathogenic microbial strains were isolated and tested for their in vitro susceptibility to piperacillin, piperacillin/tazobactam, ceftazidime, and ceftriaxone. Among all isolates, the four most frequent pathogens were Pseudomonas aeruginosa (132 isolates, 24%), Streptococcus pyogenes (99 isolates, 18%), Staphylococcus aureus (93 isolates, 17%), and Klebsiella pneumoniae (46 isolates, 8%). The susceptibility of gram-positive isolates ranged from 97.5% to 95.1%, and no remarkable difference was found in the antibacterial activity of tested b-lactam antibiotics. The susceptibility of gram-negative isolates to piperacillin and piperacillin/tazobactam was also similar: 96.5% and 97.1%, respectively. In contrast, differences were found between piperacillin (or piperacillin/tazobactam) and either ceftazidime (p=0.003) or ceftriaxone (p<0.0003) in gram-negative isolates. We conclude that, despite the extensive use of beta-lactam antibiotics (piperacillin, ceftazidime, and ceftriaxone) in medical practice during the past three decades, the susceptibility of the most common pathogens involved in the etiology of upper and lower respiratory tract infections to these antibiotics is still high. In particular, bacterial resistance developed by gram-positive organisms against piperacillin is negligible and not alarming.

[Bronchoalveolar lavage in lower respiratory tract infections in patients with bronchopulmonary carcinoma. Our experience]

In order to evaluate the usefulness of the endoscopic procedures with BAL, we conducted a study on 92 patients with diagnosis of lung cancer, underwent to chemotherapy, identifying pathogenic species involved and the antibiotic sensibility and antibiotic resistance. Moreover, to evaluate possible modifications of alveolar cell population in neutropenic patients, we studied the specimens from BALs performed via fibreoptic bronchoscopy.

METHODS

The cellular pattern of BALs in terms of concentration of total cells, concentrations of alveolar macrophages (AMs), of polymorphonucleates (PMNs) and lymphocytes (Ls) were compared in neutropenic and non-neutropenic patients.

RESULTS

In the statistical analysis of our study we found a correlation, statistically significant, between patients with neutropenic episodes on the previous chemotherapy courses and incidence of LTRI. The mean concentrations x 100,000/ml of BAL fluid of total alveolar cells, AMs, PMNs and Ls were significantly lower, after chemotherapy, in group of neutropenic patients than in non neutropenic patients, respectively.

CONCLUSIONS

In this study we found that during neutropenia the alveolar cell population was quantitatively deficient, confirming the hypothesis, proposed by other authors, of "lung aplasia" as a consequence or a concomitant event of chemotherapy-induced marrow toxicity.

[Study of phospholipid components in bronchoalveolar wash surfactants in laryngectomized patients]

Surfactants serve to keep the dimension of the lower airways normal. They regulate alveolar stability, guaranteeing uniform lung insufflation. In order to evaluate pulmonary surfactant modifications during chronic obstructive disorders of the airways, the phospholipid component in the surfactants was studied using the Broncho-Alveolar Wash (BAW). Ten subjects who had undergone laryngectomy and who were suffering from stable, chronic obstructive broncho-pneumopathy (COBP) with marked hypersecretion were studied along with a control group of 7 smokers showing no signs of COBP. As compared to the controls, the laryngectomy patients showed a statistically significant reduction in the total phospholipid content and a different concentration of some important phospholipid fractions. The laryngectomy patients showed varying degrees of COBP because of their previous smoking history: as in ex-smokers where a the "biochemical" damage induced by cigarette smoking is partially repaired. On the other hand, while in the group of smokers the damage, expressed as the total phospholipid content, was quite noteworthy (reduction in this content was up to 10 times that found in the non-smoking subjects), the ex-smoking laryngectomy patients revealed less marked, yet still significant, damage.

[The quality of life of the geriatric patient after a surgical intervention. VI. Interventions on the biliary tract]

After reviewing the literature on this subject, the authors examine the quality of life of geriatric patients after biliary tract surgery secondary to biliary tract carcinoma or non-neoplastic pathologies. From an analysis of the results the authors conclude that surgery is useful not only in non-neoplastic forms, but also in the event of carcinoma given that it is possible to improve the quality of life of these patients.

[Quality of life in geriatric patients after surgery. Note V. Pancreatic surgery]

After a brief review of the literature on this topic, the authors examine the Quality of Life in patients undergoing surgery for neoplasia of the pancreas. They found that radical pancreatic surgery for cancer in elderly patients produced better results than hepatic surgery, even if the death rate was again very high (45.95%). It is very important to underline that the patient's general conditions are very important in this form of surgery. They provide the basis for selecting derivative, endoscopic or percutaneous surgery, with the possible application of an endoprosthesis so as to treat jaundice and improve the patient's Quality of Life.

Chronic bronchitis: reflex on the pulmonary circulation

Chronic obstructive pulmonary disease (COPD) is characterized by lower alveolar oxygen content and hypoxia. Hypoxia itself is able to evoke a vascular reflex in a pulmonary vasoconstriction, the explanation of which is, in part, unknown. Pulmonary vasoconstriction leads to different degrees of pulmonary artery pressure (PAP) increase which statistically suggests that the higher the PAP, the poorer the survival rate. Many substances are involved in the vascular homeostasis. An important role is played by cyclooxygenase as well as lipoxygenase pathways metabolites, the antagonists of which have been extensively used in the treatment of pulmonary hypertension in subjects suffering from COPD. An even more important role is played by the endothelium. It is able to modify its metabolism towards the production of substances (e.g., endothelin, EDRF, etc.) which are able to negatively influence the vascular tone. Complete identification of such substances, when possible, would allow us to have a better understanding of the complexity of the mechanism which controls the pulmonary vascular district. In this direction we could hopefully look forward to the detection of specific new drugs able to improve the management of the disease by preventing it from worsening to that extent which statistically and drastically correlates with the worst prognosis.

[Quality of life in the aged after surgery. IV. Pathology of the esophagus]

Following a careful examination of the literature on the subject, the authors examine the follow-up records of all patients operated over the past 10 years for non-neoplastic and neoplastic esophageal pathologies. From the results it emerged that all those operated for non-neoplastic pathologies were still living and their quality of life was good with a very high proportion of patients presenting a score of 100 for Karnofsky's index. With regard to neoplastic forms, on the other hand, many patients had died (approximately 50%), but the majority of those living, who had undergone gastro-esophageal resection and consequent esophago-gastrostomy with thoracization of the stomach, were well with a Karnofsky score of 100. The authors explain these results by taking into account the general conditions (biological age) of patients and conclude that surgery is advisable in both non-neoplastic and neoplastic forms, given that it is important to try to improve the quality of life even in the latter.

[The quality of life of the elderly after a surgical intervention. II. Gastric carcinoma]

Having reviewed the literature on this topic, the authors examined the "quality of life" of elderly patients undergoing surgery for gastric carcinoma over the past 5 years. From the results obtained it was seen that the most frequent operation was total gastrectomy (51.1%), followed by gastric resection (48.9%); it was therefore possible to assert that living patients were all well, with a score of 100 on Karnofsky's scale (22.40%), despite the high percentage of deaths during the period examined. The authors therefore concluded that, given that the "quality of life" of those undergoing surgery was satisfactory, it is worthwhile operating whenever possible to give geriatric patients the possibility of leading a normal life.

[Tumors of the breast in old age]

After reviewing the literature on this topic the authors studied all patients admitted to the Institute of Surgical Pathology I at the University of Pavia for breast cancer between 1-1-1974. An analysis of the findings revealed that: (a) Out of 993 patients with breast cancer, 204 (20.54%) belonged to the geriatric age group (> 65 years old) and of the latter 135 (66.17%) belonged to the 3rd age group and 69 (33.82%) belonged to the 4th age group (> 75 years old). (b) In the 3rd age group 25 (18.51%) were benign tumours and 110 (81.48%) were malignant, whereas in the 4th age group 4 (5.79%) were benign and 65 (94.20%) were malignant. (c) Familial patterns were also examined and were found to be positive in 47 (23.03%) cases in the 3rd age group and in 30 (14.71%) in the 4th age group. (d) In the physiological anamnesis it is interesting to note that there was 1 menarche before 12 (0.9%) in the 3rd age group; delayed menopause (after 50) in 66 cases (60%) in the 3 rd age group and in 29 cases (44.61%) in the 4 th age group. (e) In the pathological anamnesis of the patients in question it was observed that the most frequent site of previous tumours was the breast (72 cases, equivalent to 10.9% in the 3rd age group; 9 cases, 13.8% in the 4th age group). (f) In the next pathological anamnesis and at EOL it was observed that the tumours was most often found in the supero-external quadrant, in the right breast in the 3rd age group (66 cases, 48.89%) and in the left one in the 4th age group (42 cases, 60.87%). (g) Test included breast cancer scan, mammography, aspirated needle and biopsy where required. (h) Surgery in the form of Halsted's mastectomy was the preferred therapy and as early as possible. Some Authors use conservative therapy. (i) Histological tests were performed in all patients and revealed that the most frequent malignant tumour was ductal carcinoma. (j) Postoperative complications took the form of wound suppuration. (k) Only one tumour (carcinoma) was observed in male patient aged 83 years old, without metastasis. From the above findings it can be concluded that the most evident risk factor for breast cancer is the influence of the estrogen hormone.

[The quality of life of the elderly patient after a surgical intervention. I. Interventions on the colon]

Following a brief review of the literature on this topic, the paper analyses a series of geriatric undergoing surgery for cancer of the large intestine and controlled during follow-up over the past years. From the results obtained, the authors assessed the quality of life of these patients according to Masera and Esposito's classification, as a state of well-being, intermediate or illness: it was found that 78.7% were in a state of well-being, 10.3% were unchanged, 12.1% were in a state of illness, and only 6.9% had died. The authors therefore concluded that the quality of life in the majority of elderly patients undergoing surgery is good, thus encouraging surgeons to intervene.

[The use of recombinant interferon alfa-2b in the follow-up of patients laryngectomized for advanced stage carcinoma]

The AA. report the results of an experimental investigation on 60 subjects who underwent surgery for advanced stage carcinoma of the glottic larynx and treated with alpha 2b recombinant interferon at the dosage of 3,000,000 ul three times a week, before a six-months follow-up. The patients were examined also as to the respiratory functionality and the monitoring of some biological markers of cancers (CEA, TPA, Ca 125, Ca 15.3). The AA. support the satisfactory tolerability of alpha interferon which showed expected side effects; these effects were controlled by the symptomatic treatment, and their metabolic parameters as well as the ones related to the respiratory functionality kept always their valves in the average. The monitoring of biological markers, seems to support a real usefulness in the treatment with alpha interferon, even if a statistically meaningful record couldn't be noticed.

[The usefulness of monoclonal antibodies in the diagnosis of lung carcinoma]

Monoclonal antibodies detection represented a turning point in field of immunological and biological research. Their application has rapidly extended at immunopathology as well as immunodiagnosis and immunotherapy fields. In oncological field monoclonal antibodies has proved a great usefulness in diagnosis of several districts neoplasm. Monoclonal antibodies are utilized in differential diagnosis of different histologic types of lung cancer; in bone marrow metastasis early detection; and, experimentally, in "in vivo" diagnosis of lung cancer via peripheral blood sample examination. Authors relate about more recent literature about this specific topic.

[Bronchoalveolar lavage in the diagnosis of cancer]

Bronchoalveolar lavage (BAL) is a widely used clinical procedure. To determine if BAL could provide useful information in the detection of cancer, 850 lavages from 421 patients having BAL for a variety of indications, 50 lavages in patients with Hodgkin's disease and 20 patients with breast cancer undergoing bon marrow transplant were reviewed. BALs were performed with the technique established by Rennard and coll. in which 5 successive 20 cc aliquots are infused in a wedge position. The return from the first aliquot was processed separately from the subsequent four aliquots. Diff-Quick stained cytocentrifuge preparations and Papanicolaou stained millipore filter preparations were analyzed. Thirty-five patients had biopsy-proven lung cancer. In 24 (68.6%) of these, BAL revealed cells diagnostic of malignancy. There were no false positives. Six out of 50 Hodgkin's disease patients had Reed Sternberg cells detected on BAL, and 7/20 breast cancer patients had malignant cells on BAL prior to chemotherapy. In summary, the routine performance of BAL, an easily performed and well-tolerated procedure, may prove to be useful in the routine assessment of patients for cancer.

[Thymidine kinase as a biological marker in neoplasms of the lung and mediastinum]

Thymidine kinase (TK) is a biological marker recently used in diagnosis and monitoring of pulmonary and mediastinal malignant neoplasms. Authors report more recent clinical evidences of literature and, in the meanwhile, they report their personal experiences about a 20 patients group suffering of lung cancer and Hodgkin disease. Their study demonstrates a good sensitivity of TK as biological marker of SCLC and a lower sensitivity in case of NSCLC and Hodgkin disease. It has been possible to contribute to establishment of normal range values, on account of 10 healthy volunteer group blood sample assays.

[A controlled clinical study of Pneumorel Retard tablets in the treatment of chronic bronchitis (author's transl)]

The authors studied the action of Pneumorel retard tablets in the treatment of chronic bronchitis, comparing 2 groups of 20 patients each, one group was prescribed 1 pneumorel retard tablet in the morning and evening and the other group was treated with a speciality associating proteolytic enzymes and balsamics; the 2 groups also received an antibiotic treatment. The duration of the treatments was 20 days, with controls at entry, 10 days and 20 days later. Pneumorel retard showed to be significantly more active on the criteria studied (cough, dyspnea, expectoration, signs of auscultation) and this more often than not from the 10th day of treatment. Clinical and biological tolerance was perfect concerning the hepatic sphere, gastrointestinal, renal or cardiovascular systems. The convenience of the use of Pneumorel retard is particularly indicated in the thorough long-term treatment of chronic bronchitis, in preventing episodes of over-infection, worsening the disease.