RESUMO
OBJECTIVE: This study aims to explore how timing of interval of cholecystectomy (IC) after percutaneous transhepatic cholecystostomy tube (PTC) placement impacts post-operative outcomes. METHODS: A retrospective database analysis of New York State SPARCs database of IC between 2005 and 2015. The timing for IC ranged between > 1 week and < 2 years. Patients undergoing this procedure were further divided into quartiles using 4-time intervals; 1-5 weeks (Q1), 5-8 weeks (Q2), 8-12 weeks(Q3), and > 12 weeks(Q4). The study's primary outcome was hospital length of stay (LOS). Secondary outcomes included discharge status, 30-day readmission, 30-day ED visit, and 90-day reoperation, surgery type, complication, and bile duct injury. Multivariable regression models were used to compare patients across the four-time intervals after adjusting for confounding factors. RESULTS: A total of 1038 patients with a history of PTC followed by IC between > 1 week and < 2 years were included in the final analysis. The median time to IC was 7.7 weeks. Q2 and Q3 both had a significantly higher median LOS of 3 days versus Q1 and Q4 at median of 5 days (p < 0.0001). Patients from racial and ethnic minorities (e.g., African Americans and Hispanics) were more likely to get their IC after 12 weeks (p < 0.05). Further, Black patients had a significantly higher median LOS than White, non-Hispanic patients (8 days vs 4 days, p < 0.0001) and were more likely to have open procedure. Multivariable regression analysis identified shorter LOS during Q2 (Ratio, 0.76, 95%, 0.67-0.87, p < 0.0001), and Q3 (Ratio 0.75, 95% CI, 065-0.86, p < 0.0001) compared to those who got their IC in Q4. Similar findings exist when comparing Q2 and Q3 to those receiving treatment during Q1. CONCLUSION: A time interval of 5-12 weeks between PTC and IC was associated with a decreased LOS. This study also suggests the persistence of racial disparities among these patients.
Assuntos
Colecistostomia , Humanos , Colecistostomia/métodos , Estudos Retrospectivos , Resultado do Tratamento , Colecistectomia/efeitos adversos , Tempo de InternaçãoRESUMO
Macrophage colony-stimulating factor (M-CSF) influences the proliferation and survival of mononuclear phagocytes through the receptor CSF-1R. The adaptor protein DAP12 is critical for the function of mononuclear phagocytes. DAP12-mutant mice and humans have defects in osteoclasts and microglia, as well as brain and bone abnormalities. Here we show DAP12 deficiency impaired the M-CSF-induced proliferation and survival of macrophages in vitro. DAP12-deficient mice had fewer microglia in defined central nervous system areas, and DAP12-deficient progenitors regenerated myeloid cells inefficiently after bone marrow transplantation. Signaling by M-CSF through CSF-1R induced the stabilization and nuclear translocation of beta-catenin, which activated genes involved in the cell cycle. DAP12 was essential for phosphorylation and nuclear accumulation of beta-catenin. Our results provide a mechanistic explanation for the many defects of DAP12-deficient mononuclear phagocytes.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proliferação de Células/efeitos dos fármacos , Fator Estimulador de Colônias de Macrófagos/farmacologia , Macrófagos/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , beta Catenina/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Proteínas de Ligação ao Cálcio/metabolismo , Adesão Celular/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Citometria de Fluxo , Quinase 2 de Adesão Focal/metabolismo , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Immunoblotting , Imuno-Histoquímica , Macrófagos/citologia , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos , Camundongos Knockout , Camundongos Transgênicos , Proteínas dos Microfilamentos , FosforilaçãoRESUMO
BACKGROUND: The availability of two genetically very similar cell lines (A and B) derived from the laboratory isolate Entamoeba histolytica HM-1:IMSS, which differ in their virulence properties, provides a powerful tool for identifying pathogenicity factors of the causative agent of human amoebiasis. Cell line A is incapable inducing liver abscesses in gerbils, whereas interaction with cell line B leads to considerable abscess formation. Phenotypic characterization of both cell lines revealed that trophozoites from the pathogenic cell line B have a larger cell size, an increased growth rate in vitro, an increased cysteine peptidase activity and higher resistance to nitric oxide stress. To find proteins that may serve as virulence factors, the proteomes of both cell lines were previously studied, resulting in the identification of a limited number of differentially synthesized proteins. This study aims to identify additional genes, serving as virulence factors, or virulence markers. RESULTS: To obtain a comprehensive picture of the differences between the cell lines, we compared their transcriptomes using an oligonucleotide-based microarray and confirmed findings with quantitative real-time PCR. Out of 6242 genes represented on the array, 87 are differentially transcribed (> or = two-fold) in the two cell lines. Approximately 50% code for hypothetical proteins. Interestingly, only 19 genes show a five-fold or higher differential expression. These include three rab7 GTPases, which were found with a higher abundance in the non-pathogenic cell line A. The aig1-like GTPasesare of special interest because the majority of them show higher levels of transcription in the pathogenic cell line B. Only two molecules were found to be differentially expressed between the two cell lines in both this study and our previous proteomic approach. CONCLUSIONS: In this study we have identified a defined set of genes that are differentially transcribed between the non-pathogenic cell line A and the pathogenic cell line B of E. histolytica. The identification of transcription profiles unique for amoebic cell lines with pathogenic phenotypes may help to elucidate the transcriptional framework of E. histolytica pathogenicity and serve as a basis for identifying transcriptional markers and virulence factors.
Assuntos
Entamoeba histolytica/genética , Entamoeba histolytica/patogenicidade , Perfilação da Expressão Gênica , Animais , DNA de Protozoário/genética , Entamoeba histolytica/enzimologia , GTP Fosfo-Hidrolases/genética , Genes de Protozoários , Gerbillinae , Masculino , Análise de Sequência com Séries de Oligonucleotídeos , Fatores de Virulência/genéticaRESUMO
The availability of Rahman, and the virulent HM-1:IMSS strain of E. histolytica, provides a powerful tool for identifying virulence factors of E. histolytica. Here we report an attempt to identify potential virulence factors of E. histolytica by comparing the transcriptome of E. histolytica HM-1:IMSS and E. histolytica Rahman. With phenotypically defined strains, we compared the transcriptome of Rahman and HM-1:IMSS using a custom 70mer oligonucleotide based microarray that has essentially full representation of the E. histolytica HM-1:IMSS genome. We find extensive differences between the two strains, including distinct patterns of gene expression of cysteine proteinases, AIG family members, and lectin light chains.
Assuntos
Calmodulina/genética , Cisteína Endopeptidases/genética , Entamoeba histolytica/genética , Entamoeba histolytica/patogenicidade , Perfilação da Expressão Gênica , Lectinas/genética , Fatores de Virulência/genética , Animais , Entamoeba histolytica/classificação , Regulação da Expressão Gênica , Análise de Sequência com Séries de Oligonucleotídeos , Fenótipo , Transcrição Gênica/genética , Virulência/genéticaRESUMO
As international travel and human encroachment into previously isolated areas have increased, so too has the potential for the emergence of new infectious diseases. Populations likely to be susceptible to new infectious diseases have also increased in size. The past three decades have seen outbreaks of diseases caused by parvoviruses, Nipah virus, circoviruses, and prions. Infectious pathogens such as these are formidable opponents; they can adapt to new hosts or cause variant diseases within new hosts. Many are also resistant to current inactivation techniques. In order to prevent or contain outbreaks, pathogens that emerge must be identified quickly and efficiently; research and ongoing global surveillance are therefore of primary importance. To effectively protect the blood supply and blood-based therapies, this research should include investigations into improved techniques for detection, screening, and viral inactivation, as well as into ways to reduce patient exposure to infectious pathogens via therapeutic agents. The proactive devotion of appropriate resources to infectious disease containment and prevention prior to an epidemic should be perceived as both essential public health policy and cost effective.
Assuntos
Surtos de Doenças/prevenção & controle , Doenças Priônicas/epidemiologia , Doenças Priônicas/transmissão , Viroses/epidemiologia , Viroses/transmissão , Animais , Circovirus , Humanos , Parvovirus , Saúde Pública/economia , Risco , Viagem , Zoonoses/epidemiologia , Zoonoses/transmissãoRESUMO
The persistence of amebiasis as a global health problem, despite the availability of effective treatment, has led to the search for vaccines to prevent this deadly disease. Recent clinical studies suggest that mucosal immunity could provide some protection against recurrent intestinal infection with E. histolytica, but there is contradictory evidence about protective immunity after amebic liver abscess. Progress in vaccine development has been facilitated by new animal models that allow better testing of potential vaccine candidates and by the application of recombinant technology to vaccine design. Oral vaccines utilizing amebic antigens either co-administered with some form of cholera toxin or expressed in attenuated strains of Salmonella or Vibrio cholera have been developed and tested in animals for mucosal immunogenicity. Although there has been significant progress on a number of fronts, there are unanswered questions regarding the effectiveness of immune responses in preventing disease in man and, as yet, no testing of any of these vaccines in humans has been performed.
Assuntos
Entamebíase/prevenção & controle , Vacinas Protozoárias/uso terapêutico , Estudos de Viabilidade , HumanosRESUMO
The recent publication of the protozoan parasite Entamoeba histolytica genome provides new insights into eukaryotic evolution, the role of lateral gene transfer in amebic biology and the adaptations required for eukaryotes that reside within the human intestine.
Assuntos
Entamoeba histolytica/genética , Genoma de Protozoário , Animais , Evolução Molecular , Genes de ProtozoáriosRESUMO
The ADHE family of enzymes are bifunctional acetaldehyde dehydrogenase (ALDH)/alcohol dehydrogenase (ADH) enzymes that probably arose from the fusion of genes encoding separate ALDH and ADH enzymes. Here we have used the Entamoeba histolytica alcohol dehydrogenase 2 (EhADH2) enzyme as a prototype to analyze the structure and function of the ALDH domain of ADHE enzymes. We find that the N-terminal domain of EhADH2, encompassing amino acids 1-446, is sufficient for ALDH activity, consistent with the concept that EhADH2, and other members of the ADHE family comprise fusion peptides. In addition, we show, using site directed mutagenesis, that the catalytic mechanism for the ALDH activity appears to be similar to that described for other members of the ALDH extended family.
Assuntos
Álcool Desidrogenase/química , Entamoeba histolytica/enzimologia , Álcool Desidrogenase/genética , Álcool Desidrogenase/metabolismo , Aldeído Oxirredutases/química , Aldeído Oxirredutases/genética , Aldeído Oxirredutases/metabolismo , Sequência de Aminoácidos , Animais , Entamoeba histolytica/genética , Escherichia coli/genética , Proteínas de Escherichia coli , Genes de Protozoários , Dados de Sequência Molecular , Estrutura Molecular , Complexos Multienzimáticos/química , Complexos Multienzimáticos/genética , Complexos Multienzimáticos/metabolismo , Mutagênese Sítio-Dirigida , Estrutura Terciária de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Homologia de Sequência de AminoácidosAssuntos
Proteínas de Bactérias/metabolismo , Entamoeba histolytica/metabolismo , Leucina/química , Proteínas de Membrana/química , Proteínas de Membrana/metabolismo , Proteínas de Protozoários/metabolismo , Sequências Repetitivas de Ácido Nucleico/genética , Sequência de Aminoácidos , Animais , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Clonagem Molecular , Entamoeba histolytica/genética , Proteínas de Membrana/genética , Repetições Minissatélites , Dados de Sequência Molecular , Proteínas de Protozoários/química , Proteínas de Protozoários/genética , Análise de Sequência de DNARESUMO
The protozoan intestinal parasite Entamoeba histolytica infects millions of people worldwide and is capable of causing amebic dysentery and amebic liver abscess. The closely related species Entamoeba dispar colonizes many more individuals, but this organism does not induce disease. To identify molecular differences between these two organisms that may account for their differential ability to cause disease in humans, we used two-dimensional gel-based (DIGE) proteomic analysis to compare whole cell lysates of E. histolytica and E. dispar. We observed 141 spots expressed at a substantially (>5-fold) higher level in E. histolytica HM-1:IMSS than E. dispar and 189 spots showing the opposite pattern. Strikingly, 3 of 4 proteins consistently identified as different at a greater than 5-fold level between E. histolytica HM-1:IMSS and E. dispar were identical to proteins recently identified as differentially expressed between E. histolytica HM-1:IMSS and the reduced virulence strain E. histolytica Rahman. One of these was E. histolytica alcohol dehydrogenase 3 (EhADH3). We found that E. histolytica possesses a higher level of NADP-dependent alcohol dehydrogenase activity than E. dispar and that some EhADH3 can be localized to the surface of E. histolytica. Episomal overexpression of EhADH3 in E. histolytica trophozoites resulted in only subtle phenotypic differences in E. histolytica virulence in animal models of amebic colitis and amebic liver abscess, making it difficult to directly link EhADH3 levels to virulence differences between E. histolytica and less-pathogenic Entamoeba.
Assuntos
Álcool Desidrogenase/fisiologia , Entamoeba/química , Entamoeba/patogenicidade , Entamebíase/patologia , Proteoma/análise , Proteínas de Protozoários/análise , Fatores de Virulência/fisiologia , Álcool Desidrogenase/metabolismo , Animais , Disenteria Amebiana/parasitologia , Disenteria Amebiana/patologia , Eletroforese em Gel Bidimensional , Entamebíase/parasitologia , Dosagem de Genes , Humanos , Abscesso Hepático/parasitologia , Abscesso Hepático/patologia , Camundongos , Camundongos Endogâmicos BALB C , Virulência , Fatores de Virulência/metabolismoRESUMO
Men are more than 7 times more likely to develop amebic liver abscess or amebic dysentery caused by Entamoeba histolytica than women. Because the complement system could play a key role in controlling amebiasis, we determined whether serum from men and women differ in the ability to kill amebic trophozoites. We found that serum from women was significantly more effective in killing E. histolytica trophozoites than serum from men, and this killing was complement dependent. Our results provide a possible explanation for the differential susceptibility of men and women to amebic liver abscess and amebic colitis.
Assuntos
Proteínas do Sistema Complemento/fisiologia , Suscetibilidade a Doenças , Entamoeba histolytica/imunologia , Entamebíase/imunologia , Fatores Sexuais , Animais , Entamebíase/sangue , Feminino , Humanos , MasculinoRESUMO
Antimicrobial factors are efficient defense components of the innate immunity, playing a crucial role in the intestinal homeostasis and protection against pathogens. In this study, we report that upon infection of polarized human intestinal cells in vitro, virulent Shigella flexneri suppress transcription of several genes encoding antimicrobial cationic peptides, particularly the human beta-defensin hBD-3, which we show to be especially active against S. flexneri. This is an example of targeted survival strategy. We also identify the MxiE bacterial regulator, which controls a regulon encompassing a set of virulence plasmid-encoded effectors injected into host cells and regulating innate signaling, as being responsible for this dedicated regulatory process. In vivo, in a model of human intestinal xenotransplant, we confirm at the transcriptional and translational level, the presence of a dedicated MxiE-dependent system allowing S. flexneri to suppress expression of antimicrobial cationic peptides and promoting its deeper progression toward intestinal crypts. We demonstrate that this system is also able to down-regulate additional innate immunity genes, such as the chemokine CCL20 gene, leading to compromised recruitment of dendritic cells to the lamina propria of infected tissues. Thus, S. flexneri has developed a dedicated strategy to weaken the innate immunity to manage its survival and colonization ability in the intestine.
Assuntos
Peptídeos Catiônicos Antimicrobianos/genética , Disenteria Bacilar/imunologia , Imunidade Inata , Shigella flexneri/imunologia , Shigella flexneri/patogenicidade , Linhagem Celular Tumoral , Neoplasias do Colo , Primers do DNA , Disenteria Bacilar/genética , Células Epiteliais/imunologia , Regulação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase , RNA Neoplásico/genética , Transplante Heterólogo , VirulênciaRESUMO
We hypothesized that individuals who develop fever after smallpox vaccination have genetically determined differences in their immune responses to vaccinia virus. We looked for an association between the development of fever and single-nucleotide polymorphisms (SNPs) in 19 candidate genes in 346 individuals previously assessed for clinical responses to smallpox vaccination. Fever after smallpox vaccination is associated with specific haplotypes in the interleukin (IL)-1 gene complex and in the IL18 gene. A haplotype in the IL4 gene was highly significant for reduced susceptibility to the development of fever after vaccination among vaccinia-naive individuals. Our results indicate that certain haplotypes in the IL-1 gene complex and in IL18 and IL4 predict an altered likelihood of the development of fever after smallpox vaccination. Our findings also raise the possibility that these same haplotypes may identify individuals at risk for the development of fever after receipt of other live virus vaccines, providing information that could be useful in anticipating and preventing more-serious adverse events.
Assuntos
Febre/genética , Predisposição Genética para Doença , Vacina Antivariólica/efeitos adversos , Vacinação/efeitos adversos , Vacinas Atenuadas/efeitos adversos , Adulto , Feminino , Febre/imunologia , Febre/virologia , Seguimentos , Haplótipos , Humanos , Interleucina-1/genética , Interleucina-18/genética , Interleucina-4/genética , Masculino , Pessoa de Meia-Idade , Receptores Tipo I de Interleucina-1/genética , Vacina Antivariólica/imunologia , Vacinas Atenuadas/imunologiaRESUMO
Cysteine proteinases are key virulence factors of the protozoan parasite Entamoeba histolytica. We have shown that cysteine proteinases play a central role in tissue invasion and disruption of host defenses by digesting components of the extracellular matrix, immunoglobulins, complement, and cytokines. Analysis of the E. histolytica genome project has revealed more than 40 genes encoding cysteine proteinases. We have focused on E. histolytica cysteine proteinase 1 (EhCP1) because it is one of two cysteine proteinases unique to invasive E. histolytica and is highly expressed and released. Recombinant EhCP1 was expressed in Escherichia coli and refolded to an active enzyme with a pH optimum of 6.0. We used positional-scanning synthetic tetrapeptide combinatorial libraries to map the specificity of the P1 to P4 subsites of the active site cleft. Arginine was strongly preferred at P2, an unusual specificity among clan CA proteinases. A new vinyl sulfone inhibitor, WRR483, was synthesized based on this specificity to target EhCP1. Recombinant EhCP1 cleaved key components of the host immune system, C3, immunoglobulin G, and pro-interleukin-18, in a time- and dose-dependent manner. EhCP1 localized to large cytoplasmic vesicles, distinct from the sites of other proteinases. To gain insight into the role of secreted cysteine proteinases in amebic invasion, we tested the effect of the vinyl sulfone cysteine proteinase inhibitors K11777 and WRR483 on invasion of human colonic xenografts. The resultant dramatic inhibition of invasion by both inhibitors in this human colonic model of amebiasis strongly suggests a significant role of secreted amebic proteinases, such as EhCP1, in the pathogenesis of amebiasis.
Assuntos
Colo/parasitologia , Cisteína Endopeptidases/metabolismo , Inibidores de Cisteína Proteinase/metabolismo , Entamoeba histolytica/enzimologia , Entamoeba histolytica/patogenicidade , Proteínas de Protozoários/metabolismo , Animais , Colo/patologia , Cisteína Endopeptidases/química , Cisteína Endopeptidases/genética , Modelos Animais de Doenças , Entamoeba histolytica/fisiologia , Ativação Enzimática , Humanos , Concentração de Íons de Hidrogênio , Camundongos , Camundongos SCID , Conformação Proteica , Dobramento de Proteína , Proteínas de Protozoários/química , Proteínas de Protozoários/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Especificidade por Substrato , Sulfonas/química , Sulfonas/metabolismo , Transplante Heterólogo , Fatores de Virulência/genética , Fatores de Virulência/metabolismoRESUMO
BACKGROUND: Vaccinia virus (VV) membrane proteins are candidates for orthopoxvirus subunit vaccines and potential targets for therapeutic antibodies. Human antibody responses to these proteins after VV vaccination have not been well characterized. METHODS: Pre- and postvaccination (day 26-30) serum specimens from 80 VV vaccine recipients were examined for immunoglobulin G antibodies specific for B5, A33, A27, and L1 by enzyme-linked immunosorbent assay (ELISA). Responses were compared between vaccinia-naive and previously vaccinated (nonnaive) recipients and between nonnaive recipients of undiluted or 1 : 10 diluted vaccine. RESULTS: VV vaccination elicited anti-A33 and anti-A27 antibodies in nearly all vaccinia-naive subjects (100% and 93%, respectively). Preexisting antibodies were commonly detected in nonnaive subjects (for anti-B5, 68%; for anti-A33, 59%; for anti-A27, 38%; and for anti-L1, 10%). Anti-B5 antibodies were strongly boosted by undiluted vaccine (geometric mean titer [GMT], 151 vs. 1010 for pre- vs. postvaccination; P<.001), whereas anti-L1 antibody responses were less robust (detection rate, 31%; GMT, 75) in nonnaive subjects. Diluted vaccine elicited antibody responses that were similar to those elicited by undiluted vaccine. CONCLUSIONS: Vaccination with VV elicits long-lived specific antibody responses directed against VV membrane proteins that vary by previous vaccination status but not with respect to 10-fold dilution of vaccine. B5, A33, and A27 should be considered for inclusion in future human orthopoxvirus subunit vaccines.
Assuntos
Especificidade de Anticorpos/imunologia , Vacina Antivariólica/imunologia , Vaccinia virus/imunologia , Proteínas do Envelope Viral/imunologia , Adolescente , Adulto , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Imunoglobulina G/análise , MasculinoRESUMO
The liver has the remarkable ability to respond to injury with repair and regeneration. The protozoan parasite Entamoeba histolytica is the major cause of liver abscess worldwide. We report a transcriptional analysis of the response of mouse liver to E. histolytica infection, the first study looking at acute liver infection by a non-viral pathogen. Focusing on early time points, we identified 764 genes with altered transcriptional levels in amebic liver abscess. The response to infection is rapid and complex, with concurrent increased expression of genes linked to host defence through IL-1, TLR2, or interferon-induced pathways, liver regeneration via activation of IL-6 pathways, and genes associated with programmed cell death possibly through TNFalpha or Fas pathways. A comparison of amebic liver infection with the liver response to partial hepatectomy or toxins reveals striking similarities between amebic liver abscess and non-infectious injury in key components of the liver regeneration pathways. However, the response in amebic liver abscess is biased towards apoptosis when compared with acute liver injury from hepatectomy, toxins, or other forms of liver infection. E. histolytica infection of the liver simultaneously activates inflammatory, regenerative and apoptotic pathways, but the sum of these early responses is biased towards programmed cell death.
Assuntos
Apoptose , Entamoeba histolytica/patogenicidade , Abscesso Hepático Amebiano/fisiopatologia , Regeneração Hepática , Fígado/fisiopatologia , Proteínas/metabolismo , Animais , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Inflamação , Fígado/imunologia , Fígado/parasitologia , Abscesso Hepático Amebiano/imunologia , Abscesso Hepático Amebiano/parasitologia , Camundongos , Camundongos SCID , Análise de Sequência com Séries de Oligonucleotídeos , Proteínas/genética , Transcrição GênicaRESUMO
Entamoeba histolytica is a protozoan intestinal parasite that causes amoebic colitis and amoebic liver abscess. To identify virulence factors of E. histolytica, we first defined the phenotypes of two E. histolytica strains, HM-1:IMSS, the prototype virulent strain, and E. histolytica Rahman, a strain that was reportedly less virulent than HM-1:IMSS. We found that compared with HM-1:IMSS, Rahman has a defect in erythrophagocytosis and the ability to cause amoebic colitis in human colonic xenografts. We used differential in-gel 2D electrophoresis to compare the proteome of Rahman and HM-1:IMSS, and identified six proteins that were differentially expressed above a fivefold level between the two organisms. These included two proteins with antioxidative properties (peroxiredoxin and superoxide dismutase), and three proteins of unknown function, grainin 1, grainin 2 and a protein containing a LIM-domain. Overexpression of peroxiredoxin in Rahman rendered the transgenic trophozoites more resistant to killing by H2O2 in vitro, and infection with Rahman trophozoites expressing higher levels of peroxiredoxin was associated with higher levels of intestinal inflammation in human colonic xenografts, and more severe disease based on histology. In contrast, higher levels of grainin appear to be associated with a reduced virulence phenotype, and E. histolytica HM-1:IMSS trophozoites infecting human intestinal xenografts show marked decreases in grainin expression. Our data indicate that there are definable molecular differences between Rahman and HM-1:IMSS that may explain the phenotypic differences, and identify peroxiredoxin as an important component of virulence in amoebic colitis.
Assuntos
Entamoeba histolytica/metabolismo , Entamoeba histolytica/patogenicidade , Peroxidases/metabolismo , Proteômica , Proteínas de Protozoários/metabolismo , Fatores de Virulência/metabolismo , Animais , Colo/parasitologia , Disenteria Amebiana/parasitologia , Disenteria Amebiana/patologia , Entamoeba histolytica/efeitos dos fármacos , Humanos , Peróxido de Hidrogênio/farmacologia , Camundongos , Camundongos Endogâmicos , Peroxidases/genética , Peroxirredoxinas , Proteínas de Protozoários/genética , Virulência , Fatores de Virulência/genéticaRESUMO
Amoebiasis is the second leading cause of death from parasitic disease worldwide. The causative protozoan parasite, Entamoeba histolytica, is a potent pathogen. Secreting proteinases that dissolve host tissues, killing host cells on contact, and engulfing red blood cells, E histolytica trophozoites invade the intestinal mucosa, causing amoebic colitis. In some cases amoebas breach the mucosal barrier and travel through the portal circulation to the liver, where they cause abscesses consisting of a few E histolytica trophozoites surrounding dead and dying hepatocytes and liquefied cellular debris. Amoebic liver abscesses grow inexorably and, at one time, were almost always fatal, but now even large abscesses can be cured by one dose of antibiotic. Evidence that what we thought was a single species based on morphology is, in fact, two genetically distinct species--now termed Entamoeba histolytica (the pathogen) and Entamoeba dispar (a commensal)--has turned conventional wisdom about the epidemiology and diagnosis of amoebiasis upside down. New models of disease have linked E histolytica induction of intestinal inflammation and hepatocyte programmed cell death to the pathogenesis of amoebic colitis and amoebic liver abscess.
Assuntos
Amebíase , Amebicidas/uso terapêutico , Disenteria Amebiana , Entamoeba histolytica , Adulto , Amebíase/epidemiologia , Amebíase/mortalidade , Amebíase/fisiopatologia , Amebicidas/efeitos adversos , Animais , Criança , Disenteria Amebiana/diagnóstico , Disenteria Amebiana/tratamento farmacológico , Disenteria Amebiana/patologia , Entamoeba histolytica/isolamento & purificação , Entamoeba histolytica/patogenicidade , Entamoeba histolytica/fisiologia , Feminino , Humanos , MasculinoRESUMO
Mouse-human chimeras have become a novel way to model the interactions between microbial pathogens and human cells, tissues or organs. Diseases studied with human xenografts in severe combined immunodeficient (SCID) mice include Pseudomonas aeruginosa infection in cystic fibrosis, group A streptococci and impetigo, bacillary and amoebic dysentery, and AIDS. In many cases, disease in the human xenograft appears to accurately reproduce the disease in humans, providing a powerful model for identifying virulence factors, host responses to infection and the effects of specific interventions on disease. In this review, we summarize recent studies that have used mouse-human chimeras to understand the pathophysiology of specific bacterial and protozoan infections.
Assuntos
Infecções Bacterianas , Modelos Animais de Doenças , Camundongos SCID , Infecções Protozoárias em Animais , Infecções por Protozoários , Transplante Heterólogo , Animais , Infecções Bacterianas/microbiologia , Humanos , Camundongos , Infecções por Protozoários/parasitologia , Infecções Protozoárias em Animais/parasitologiaRESUMO
The clinical presentations of bacillary dysentery caused by shigella, and amoebic dysentery caused by the protozoan parasite Entamoeba histolytica, can be indistinguishable, with both organisms causing colonic mucosal damage and ulceration. However, the two organisms are quite distinct, and have very different pathogenic mechanisms. This raises the fundamental question of whether the similar clinical manifestations reflect a stereotypic response of the human gut to mucosal injury, or whether there are differences at the molecular level in the host response to individual gut pathogens. To characterize the human colonic response to each pathogen at the molecular level, we measured the differential transcription of nearly 40,000 human genes in sections of human colonic xenografts obtained 4 and 24 h following infection with Shigella flexneri or E. histolytica. Our results indicate that much of the human colonic response to these two pathogens is stereotypic, with increased expression of genes activated in cells undergoing stress and/or hypoxic responses, genes encoding cytokines, chemokines, and mediators that are involved in immune and inflammatory responses, and genes encoding proteins involved in responses to tissue injury and in tissue repair. The responses to amoeba and Shigella were not identical however, and we found unique elements in each response that may provide new insights into the distinct pathogenic mechanisms of E. histolytica and S. flexneri.