[Role of the gut microbiome in the development and transfer of antibiotic resistances]. / Rolle des Darmmikrobioms bei der Entstehung und Weitergabe von Antibiotikaresistenzen.

Antimicrobial resistance (AR) is a natural phenomenon resulting from the exposure of bacteria to antibacterial substances. The intestinal microbiome plays a central role in the development and transmission of AR. In its physiological state, the intestinal microbiome has several mechanisms that contribute to what is referred to as colonization resistance against potentially pathogenic and often multiresistant bacteria. Exposure to broad-spectrum antibiotics can disrupt those mechanisms, facilitating colonization with these pathogens. The persistence of antibiotic selection pressure favors growth of multiresistant bacteria and their dominance within the intestinal microbiota. Under these circumstances, the risk of the development of invasive infections increases. Antibiotic stewardship programs, the use of narrow-spectrum antibiotics, and the administration of substances that protect the intestinal microbiome from antibiotic exposure can prevent these processes. Several interventions such as the administration of probiotics, oral antibiotics, and fecal microbiome transfers are potential strategies for decolonizing patients with multidrug resistant bacteria; to date, however, no intervention has been proven to be consistently effective.

Inhibiting conjugation as a tool in the fight against antibiotic resistance.

Antibiotic resistance, especially in gram-negative bacteria, is spreading globally and rapidly. Development of new antibiotics lags behind; therefore, novel approaches to the problem of antibiotic resistance are sorely needed and this commentary highlights one relatively unexplored target for drug development: conjugation. Conjugation is a common mechanism of horizontal gene transfer in bacteria that is instrumental in the spread of antibiotic resistance among bacteria. Most resistance genes are found on mobile genetic elements and primarily spread by conjugation. Furthermore, conjugative elements can act as a reservoir to maintain antibiotic resistance in the bacterial population even in the absence of antibiotic selection. Thus, conjugation can spread antibiotic resistance quickly between bacteria of the microbiome and pathogens when selective pressure (antibiotics) is introduced. Potential drug targets include the plasmid-encoded conjugation system and the host-encoded proteins important for conjugation. Ideally, a conjugation inhibitor will be used alongside antibiotics to prevent the spread of resistance to or within pathogens while not acting as a growth inhibitor itself. Inhibiting conjugation will be an important addition to our arsenal of strategies to combat the antibiotic resistance crisis, allowing us to extend the usefulness of antibiotics.

Gene therapy: advances, challenges and perspectives / Terapia gênica: avanços, desafios e perspectivas

ABSTRACT The ability to make site-specific modifications to the human genome has been an objective in medicine since the recognition of the gene as the basic unit of heredity. Thus, gene therapy is understood as the ability of genetic improvement through the correction of altered (mutated) genes or site-specific modifications that target therapeutic treatment. This therapy became possible through the advances of genetics and bioengineering that enabled manipulating vectors for delivery of extrachromosomal material to target cells. One of the main focuses of this technique is the optimization of delivery vehicles (vectors) that are mostly plasmids, nanostructured or viruses. The viruses are more often investigated due to their excellence of invading cells and inserting their genetic material. However, there is great concern regarding exacerbated immune responses and genome manipulation, especially in germ line cells. In vivo studies in in somatic cell showed satisfactory results with approved protocols in clinical trials. These trials have been conducted in the United States, Europe, Australia and China. Recent biotechnological advances, such as induced pluripotent stem cells in patients with liver diseases, chimeric antigen receptor T-cell immunotherapy, and genomic editing by CRISPR/Cas9, are addressed in this review.

RESUMO A habilidade de fazer modificações pontuais no genoma humano tem sido o objetivo da medicina desde o conhecimento do DNA como unidade básica da hereditariedade. Entende-se terapia gênica como a capacidade do melhoramento genético por meio da correção de genes alterados (mutados) ou modificações sítio-específicas, que tenham como alvo o tratamento terapêutico. Este tipo de procedimento tornou-se possível por conta dos avanços da genética e da bioengenharia, que permitiram a manipulação de vetores para a entrega do material extracromossomal em células-alvo. Um dos principais focos desta técnica é a otimização dos veículos de entrega (vetores) que, em sua maioria, são plasmídeos, nanoestruturados ou vírus − sendo estes últimos os mais estudados, devido à sua excelência em invadir as células e inserir seu material genético. No entanto, existe grande preocupação referente às respostas imunes exacerbadas e à manipulação do genoma, principalmente em linhagens germinativas. Estudos em células somáticas in vivo apresentaram resultados satisfatórios, e já existem protocolos aprovados para uso clínico. Os principais trials têm sido conduzidos nos Estados Unidos, Europa, Austrália e China. Recentes avanços biotecnológicos empregados para o aprimoramento da terapia gênica, como células-tronco pluripotentes induzidas em pacientes portadores de doenças hepáticas, imunoterapia com células T do receptor do antígeno quimera e edição genômica pelos sistema CRISPR/Cas9, são abordados nesta revisão.

In vivo transfer of human chemokine-like factor 1 gene increases peripheral blood CD34~+ stem cells after myocardial infarction in rats / 北京大学学报(医学版)

Objective: To assess the influence of different doses of CKLF1 plasmid on the dynamics and magnitude of the mobilization of the mobilization bone of marrow stem cells in a rat AMI model.Methods: Different doses of plasmid DNA encoding CKLF1 gene,empty plasmid or saline were injected into male SD rats intramuscularly with in vivo electroporation.Rats were subjected to left coronary artery ligation 6 days after gene transfer.Peripheral blood samples were drawn and CD34~+ cells were assayed by FACS calibur flow-cytometer.The changes in absolute number of CD34~+ cells were evaluated.Results: Expressions of CKLF1 mRNA and protein were detected in the injection site 7 days after gene transfer.Five days after gene transfer,the CD34~+ cells numbers in CKLF1 groups were significantly higher than those in empty plasmid group,especially in CKLF1 100?g group(16.63?10~6/L vs 4.98?10~6/L,P

Effects of FKBP12.6 gene transfection on the contractility of ventricular myocytes of rats with heart failure / 解放军医学杂志

Objective To investigate the effects of FKBP12.6 gene transfection on the contractility of ventricular myocytes of rats with heart failure.Methods Rat model of heart failure was established by a surgical operation of abdominal aortic stenosis.The enzymatic hydrolysis was employed to isolate the rats' ventricular myocytes.Mediated by adenovirus the FKBP12.6 gene was transfected into ventricular myocytes.Ad-GFP infected cardiac myocytes from heart failure rats and normal rats were used as control.Western blotting and reverse transcriptase-polymerase chain reaction(RT-PCR) were used to detect the specific overexpression of FKBP12.6.Transfected ventricular myocytes were loaded with the membrane-permeant Ca2+ dye X-rhod-1-AM.Under the condition of field stimulation,the laser confocal microscope in line-scan and plane-scan mode was used to detect the Ca2+ transients and myocytes contraction.Results The mRNA and protein levels of FKBP12.6 in the myocytes of rats with heart failure were significantly lower than that in normal myocytes(0.47?0.08 vs 0.96?0.12,0.25?0.04 vs 0.48?0.07,P

Effects of FKBP12.6 overexpression on the performance of sarcoplasmic reticulum in ventricular myocytes of rats with heart failure / 中国病理生理杂志

AIM:To study the effects of FK506 binding protein 12.6(FKBP12.6) overexpression on the performance of sarcoplasmic reticulum(SR) in ventricular myocytes of rats with heart failure.METHODS:The adenovirus(Ad)-mediated gene transfer was used to overexpress FKBP12.6 in ventricular myocytes of rats with heart failure.Western blotting and reverse transcriptase-polymerase chain reaction(RT-PCR) analysis were used to reveale specific overexpression of FKBP12.6.X-rhod-1-AM was used as the Ca2+ indicator,and cells were viewed under a confocal microscope.RESULTS:Adenovirus mediated overexpression of FKBP12.6 resulted in a 5-fold increase in relative FKBP12.6 mRNA levels and a 4-fold increase in relative FKBP12.6 protein levels at 48 h after transfection compared with control.The amplitude of the fluorescence [Ca2+]i transient was significantly increased in Ad-FKBP12.6-GFP cardiomyocytes compared with Ad-GFP myocytes(peak F/F0,3.16?0.42 vs 1.43?0.38,P

Biological characterics of human fetal cord blood mesenchymal stem cells / 中国病理生理杂志

AIM: To investigate the biological characterics of human second-trimester fetal cord blood mesenchymal stem cells (MSC) and its application prospects in utero gene transfer/therapy (IUGT). METHODS: Nuclear cells separated from cord blood were cultured in DMEM medium. Surface antigens of the MSC were analyzed by the FACScan flow cytometry. Adipogenic and osteogenic mediums were used to assess the differentiation ability of the cells. Adenovirus vector deliver green fluorescent protein gene (Ad-GFP) was used to transfected the MSC and the expressing of GFP was detected by fluorescent microscope. The MSC were injected into the liver of newborn rat. The immunofluorescence analysis was conducted to determine the presence of double-positive CD105+/CD166+ cells in different organs of rats. MSC were subcutaneous injected into the human-nonobese diabetes/severe combined immunodeficiency disease (NOD/SCID) mice and carcinogenesises of the MSC in vivo were detected by pathological diagnosis. RESULTS: MSC could be separated from fetal cord blood. These cells were uniformly positive for CD29, CD44, CD59, CD105, CD166 and negative for CD34, CD45, CD80, CD86, HLA-DR. The cells had the abilities to differentiate into adipogenic and osteogenic cells in vitro, expressed the GFP at high levels (56 32%?3 28%). The MSC were located at different organs after injected into the newborn rats and didn't have carcinogenicity in vivo. CONCLUSION: Human second-trimester fetal cord blood MSC is an promising target cells in fetal IUGT.