Cell Interaction Analysis by Imaging Flow Cytometry

Many processes such as cell adhesion, tissue development, cellular communication, inflammation, tumor metastasis, and microbial infection require direct interactions between cells. Some cell-cell interactions are transient, as is the case of the contacts between cells ofthe immune system, the interactions of white blood cells to malignant cells or to sites oftissue inflammation. These events often entail structural alterations in the point of contact ofthe cells involved, and may involve the fusion, transfer or exchange of material between thecells; which occur in a scale that is suited for optical microscopy analysis. However, due toits low throughput nature, microscopy often suffers from acquisition bias and limitedstatistical power. Moreover, because the data is typically analyzed in a qualitative manner, itis difficult to obtain standardized results. Strong scientific conclusions demand objectivecollection of large amounts of relevant information that can be analyzed in a quantitative,standardized, and statistically robust manner. Flow cytometry overcomes these problemsbut reduces the rich information available via optical microscopy to a set of intensitymeasurements. By combining high speed automated image acquisition with quantitativeimage analysis, Multispectral Imaging Flow Cytometry (MIFC) provides all the elementsrequired for discriminating cells based on intensity and appearance in a standardized andstatistical manner. In recent years, the application of this technology for the analysis of cell-cell interaction has multiplied, in particular in the field of immunology, allowing theobservation and quantification of events in a way that could not be achieved before.Fil: Payés, Cristian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Rodríguez, José A.. No especifíca;Fil: Friend, Sherree. No especifíca;Fil: Helguera, Gustavo Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentin

Cryopreservation of Cortical Tissue Blocks for the Generation of Highly Enriched Neuronal Cultures

In this study, we outline a standardized protocol for the successful cryopreservation and thawing of cortical brain tissue blocks to generate highly enriched neuronal cultures. For this protocol the freezing medium used is 10% dimethyl sulfoxide (DMSO) diluted in Hank's Buffered Salt Solution (HBSS). Blocks of cortical tissue are transferred to cryovials containing the freezing medium and slowly frozen at -1°C/min in a rate-controlled freezing container. Post-thaw processing and dissociation of frozen tissue blocks consistently produced neuronal-enriched cultures which exhibited rapid neuritic growth during the first 5 days in culture and significant expansion of the neuronal network within 10 days. Immunocytochemical staining with the astrocytic marker glial fibrillary acidic protein (GFAP) and the neuronal marker beta-tubulin class III, revealed high numbers of neurons and astrocytes in the cultures. Generation of neural precursor cell cultures after tissue block dissociation resulted in rapidly expanding neurospheres, which produced large numbers of neurons and astrocytes under differentiating conditions. This simple cryopreservation protocol allows for the rapid, efficient, and inexpensive preservation of cortical brain tissue blocks, which grants increased flexibility for later generation of neuronal, astrocyte, and neuronal precursor cell cultures

Parkinson’s Disease in a Patient with 22q11.2 Deletion Syndrome: The Relevance of Detecting Mosaicisms by Means of Cell-By-Cell Evaluation Techniques

We report the case of a male patient from an Ashkenazi Jewish ethnic group with a history of midline defects (congenital heart disease, high-arched palate and bifid uvula). At the age of 46 years, he came to our center complaining of resting tremor, and a neurological examination concluded Parkinson?s disease. As a part of his approach, genetic evaluation was performed. Fluorescence in-situ hybridization (FISH) confirmed a mosaicism of a 22q deletion in 24% of the analyzed blood cells. Also, immunohistochemical studies were performed on samples from the minor salivary glands using a SNCA antibody. Intense SNCA immunoreactive profiles were obtained for cells from the salivary glands of the patient. This is, to our knowledge, the first description of the association of amosaicism of a 22q11.2 microdeletion syndrome with Parkinson?s disease. Our findings suggest that, before excluding the involvement of the 22q11.2 deletion in the etiology of early-onset PD cases, the spectrum of evaluations should be extended to include more sensitive FISH analysis and immunohistochemical studies. The pathogenesis of early-onset PD in patients with 22q11.2 deletion syndrome remains unknown but, if elucidated, it may contribute to understanding the etiology of PD and ultimately to preventionand treatment strategies.Fil: Perandones, Claudia. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbrán"; ArgentinaFil: Farini, Veronica Lujan. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología. Centro de Estudios en Salud y Medio Ambiente; ArgentinaFil: Pellene, L. A. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Sáenz Farret, Michel. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Cuevas, S. M. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Micheli, Federico. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Radrizzani Helguera, Martin. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología. Centro de Estudios en Salud y Medio Ambiente; Argentin

Differential expression of dnaA and dosR genes among members of the Mycobacterium tuberculosis complex under oxic and hypoxic conditions

Major differences regarding the pathology and host immune response of the Beijing and Canettii genotypes of Mycobacterium tuberculosis have been reported; however, studies on the genetic expression of these genotypes during in vitro dormancy are scarce. This study examined the expression of five cell-cycle-related genes and two dormancy-related genes in M. canettii, M. tuberculosis H37Rv, and M. tuberculosis Beijing during the Wayne model of dormancy. The results showed that under hypoxic conditions the three tuberculosis genotypes were able to transcribe genes involved in DNA replication and cellular division. In addition, dosR was found to be up-regulated in M. tuberculosis Beijing during the exponential growth phase but down-regulated under hypoxic conditions. In this genotype, the replication-related gene dnaA was also strongly down-regulated. These latter two findings suggest that, compared to M. tuberculosis H37Rv and M. canettii, the Beijing genotype has a lower capacity to synthesize dosR, hspX, and dnaA mRNAs during in vitro dormancy. [Int Microbiol 2010;13(1):9-13

Insights into the mechanism of cell death induced by saporin delivered into cancer cells by an antibody fusion protein targeting the transferrin receptor 1

We previously developed an antibody-avidin fusion protein (ch128.1Av) that targets the human transferrin receptor 1 (TfR1) and exhibits direct cytotoxicity against malignant B cells in an iron-dependent manner. ch128.1Av is also a delivery system and its conjugation with biotinylated saporin (b-SO6), a plant ribosome-inactivating toxin, results in a dramatic iron-independent cytotoxicity, both in malignant cells that are sensitive or resistant to ch128.1Av alone, in which the toxin effectively inhibits protein synthesis and triggers caspase activation. We have now found that the ch128.1Av/b-SO6 complex induces a transcriptional response consistent with oxidative stress and DNA damage, a response that is not observed with ch128.1Av alone. Furthermore, we show that the antioxidant N-acetylcysteine partially blocks saporin-induced apoptosis suggesting that oxidative stress contributes to DNA damage and ultimately saporin-induced cell death. Interestingly, the toxin was detected in nuclear extracts by immunoblotting, suggesting the possibility that saporin might induce direct DNA damage. However, confocal microscopy did not show a clear and consistent pattern of intranuclear localization. Finally, using the long-term culture-initiating cell assay we found that ch128.1Av/b-SO6 is not toxic to normal human hematopoietic stem cells suggesting that this critical cell population would be preserved in therapeutic interventions using this immunotoxin.Fil: Daniels Wells, Tracy R.. University of California; Estados Unidos de América;Fil: Helguera, Gustavo Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. University of California; Estados Unidos de América;Fil: Rodríguez, José A.. University of California; Estados Unidos de América;Fil: Leoh, Lai Sum. University of California; Estados Unidos de América;Fil: Erb, Michael A.. University of California; Estados Unidos de América;Fil: Diamante, Graciel. University of California; Estados Unidos de América;Fil: Casero, David. University Of California; Estados Unidos de América;Fil: Pellegrini, Mateo. University of California; Estados Unidos de América;Fil: Martinez Maza, Otoniel. University of California; Estados Unidos de América;Fil: Penichet, Manuel L.. University of California; Estados Unidos de América

The lack of the TetR-like repressor gene BCG_2177c (Rv2160A) may help mycobacteria overcome intracellular redox stress and survive longer inside macrophages when surrounded by a lipid environment

Mycobacteria, like other microorganisms, survive under different environmental variations by expressing an efficient adaptive response, oriented by regulatory elements, such as transcriptional repressors of the TetR family. These repressors in mycobacteria also appear to be related to cholesterol metabolism. In this study, we have evaluated the effect of a fatty acid (oleic–palmitic–stearic)/cholesterol mixture on some phenotypic and genotypic characteristics of a tetR-mutant strain (BCG_2177c mutated gene) of M. bovis BCG, a homologous of Rv2160A of M. tuberculosis. In order to accomplish this, we have analyzed the global gene expression of this strain by RNA-seq and evaluated its neutral-lipid storage capacity and potential to infect macrophages. We have also determined the macrophage response by measuring some pro- and anti-inflammatory cytokine expressions. In comparison with wild-type microorganisms, we showed that the mutation in the BCG_2177c gene did not affect the growth of M. bovis BCG in the presence of lipids but it probably modified the structure/composition of its cell envelope. Compared to with dextrose, an overexpression of the transcriptome of the wild-type and mutant strains was observed when these mycobacteria were cultured in lipids, mainly at the exponential phase. Twelve putative intracellular redox balance maintenance genes and four others coding for putative transcriptional factors (including WhiB6 and three TetR-like) were the main elements repeatedly overexpressed when cultured in the presence of lipids. These genes belonged to the central part of what we called the “genetic lipid signature” for M. bovis BCG. We have also found that all these mycobacteria genotypic changes affected the outcome of BCG-infected macrophages, being the mutant strain most adapted to persist longer inside the host. This high persistence result was also confirmed when mutant-infected macrophages showed overexpression of the anti-inflammatory cytokine TGF-ß versus pro-inflammatory cytokines. In summary, the lack of this TetR-like repressor expression, within a lipid environment, may help mycobacteria overcome intracellular redox stress and survive longer inside their host

First insights into the genetic diversity of Mycobacterium tuberculosis isolates from HIV-infected Mexican patients and mutations causing multidrug resistance

<p>Abstract</p> <p>Background</p> <p>The prevalence of infections with <it>Mycobacterium tuberculosis </it>(MTb) and nontuberculous mycobacteria (NTM) species in HIV-infected patients in Mexico is unknown. The aims of this study were to determine the frequency of MTb and NTM species in HIV-infected patients from Mexico City, to evaluate the genotypic diversity of the <it>Mycobacterium tuberculosis </it>complex strains, to determine their drug resistance profiles by colorimetric microplate Alamar Blue assay (MABA), and finally, to detect mutations present in <it>kat</it>G, <it>rpo</it>B and <it>inh</it>A genes, resulting in isoniazid (INH) and rifampin (RIF) resistance.</p> <p>Results</p> <p>Of the 67 mycobacterial strains isolated, 48 were identified as MTb, 9 as <it>M. bovis</it>, 9 as <it>M. avium </it>and 1 as <it>M. intracellulare</it>. IS<it>6110</it>-RFLP of 48 MTb strains showed 27 profiles. Spoligotyping of the 48 MTb strains yielded 21 patterns, and 9 <it>M. bovis </it>strains produced 7 patterns. Eleven new spoligotypes patterns were found. A total of 40 patterns were produced from the 48 MTb strains when MIRU-VNTR was performed. Nineteen (39.6%) MTb strains were resistant to one or more drugs. One (2.1%) multidrug-resistant (MDR) strain was identified. A novel mutation was identified in a RIF-resistant strain, GAG → TCG (Glu → Ser) at codon 469 of <it>rpo</it>B gene.</p> <p>Conclusions</p> <p>This is the first molecular analysis of mycobacteria isolated from HIV-infected patients in Mexico, which describe the prevalence of different mycobacterial species in this population. A high genetic diversity of MTb strains was identified. New spoligotypes and MIRU-VNTR patterns as well as a novel mutation associated to RIF-resistance were found. This information will facilitate the tracking of different mycobacterial species in HIV-infected individuals, and monitoring the spread of these microorganisms, leading to more appropriate measures for tuberculosis control.</p

Hypothesis: Somatic Mosaicism and Parkinson Disease

Letter to the EditorFil: Perandones, Carlos Edgardo. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Pellene, L. A. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Giugni, J. C.. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Calvo, D. S.. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Raina, G. B.. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Cuevas, S. M.. Universidad de Buenos Aires. Facultad de Medicina. Hospital de Clínicas General San Martín; ArgentinaFil: Mata, I. F.. University of Washington; Estados UnidosFil: Zabetian, C. P.. University of Washington; Estados UnidosFil: Caputo, Mariela. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Servicio de Huellas Digitales Genéticas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Corach, Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Servicio de Huellas Digitales Genéticas; ArgentinaFil: Micheli, Federico. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Servicio de Huellas Digitales Genéticas; ArgentinaFil: Radrizzani Helguera, Martin. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentin

Rationale and preclinical efficacy of a novel anti-EMP2 antibody for the treatment of invasive breast cancer

Despite significant advances in biology and medicine, the incidence and mortality due to breast cancer worldwide is still unacceptably high. Thus, there is an urgent need to discover new molecular targets. In this article, we show evidence for a novel target in human breast cancer, the tetraspan protein epithelial membrane protein-2 (EMP2). Using tissue tumor arrays, protein expression of EMP2 was measured and found to be minimal in normal mammary tissue, but it was upregulated in 63% of invasive breast cancer tumors and in 73% of triple-negative tumors tested. To test the hypothesis that EMP2 may be a suitable target for therapy, we constructed a fully human immunoglobulin G1 (IgG1) antibody specific for a conserved domain of human and murine EMP2. Treatment of breast cancer cells with the anti-EMP2 IgG1 significantly inhibited EMP2-mediated signaling, blocked FAK/Src signaling, inhibited invasion, and promoted apoptosis in vitro. In both human xenograft and syngeneic metastatic tumor monotherapy models, anti-EMP2 IgG1 retarded tumor growth without detectable systemic toxicity. This antitumor effect was, in part, attributable to a potent antibody-dependent cell-mediated cytotoxicity response as well as direct cytotoxicity induced by the monoclonal antibody. Together, these results identify EMP2 as a novel therapeutic target for invasive breast cancer.Fil: Fu, Maoyong. University of California Los Angeles. David Geffen School of Medicine at UCLA; Estados UnidosFil: Maresh , Erin L.. University of California Los Angeles. David Geffen School of Medicine at UCLA; Estados UnidosFil: Helguera, Gustavo Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentina. Universidad de Buenos Aires; ArgentinaFil: Kiyohara, Meagan. University of California Los Angeles. David Geffen School of Medicine at UCLA; Estados UnidosFil: Qin, yu. University of California Los Angeles. David Geffen School of Medicine at UCLA; Estados UnidosFil: Ashki, Negin. University of California Los Angeles. David Geffen School of Medicine at UCLA; Estados UnidosFil: Daniels Wells, Tracy R.. University of California Los Angeles. David Geffen School of Medicine at UCLA; Estados UnidosFil: Aziz, Najib. University of California Los Angeles. David Geffen School of Medicine at UCLA; Estados UnidosFil: Gordon, Lynn K.. University of California Los Angeles. David Geffen School of Medicine at UCLA; Estados UnidosFil: Braun, Jonathan. University of California Los Angeles. David Geffen School of Medicine at UCLA; Estados UnidosFil: Elshimali, Yahya. Charles Drew University. Department of Pathology; Estados UnidosFil: Soslow, Robert A.. Memorial Sloan-Kettering Cancer Center. Department of Pathology; Estados UnidosFil: Penichet, Manuel L.. University of California Los Angeles. David Geffen School of Medicine at UCLA; Estados UnidosFil: Goodglick, Lee. University of California Los Angeles. David Geffen School of Medicine at UCLA; Estados UnidosFil: Wadehra, Madhuri. University of California Los Angeles. David Geffen School of Medicine at UCLA; Estados Unido