Antiporter activity of the individual complex I subunits NuoL, NuoM and NuoN from Escherichia coli analyzed in an in vivo model system

Abstract High throughput in vivo laboratory models is need for screening and identification of effective therapeutic agents to overcome microbial drug-resistance. This study was undertaken to evaluate in vivo antimicrobial efficacy of short-chain antimicrobial peptide- Cecropin A (1–7)-Melittin (CAMA) against three multi- drug resistant enteroaggregative Escherichia coli (MDR-EAEC) field isolates in a Galleria mellonella larval model. The minimum inhibitory concentration (MIC; 2.0 mg/L) and minimum bactericidal concentration (MBC; 4.0 mg/L) of CAMA were determined by microdilution assay. CAMA was found to be stable at high temperatures, physiological concentration of cationic salts and proteases; safe with sheep erythrocytes, secondary cell lines and commensal lactobacilli at lower MICs; and exhibited membrane permeabilisation. In vitro time-kill assay revealed concentration- and time-dependent clearance of MDR-EAEC in CAMA-treated groups at 30 min. CAMA- treated G. mellonella larvae exhibited an increased survival rate, reduced MDR-EAEC counts, immunomodulatory effect and proved non-toxic which concurred with histopathological findings. CAMA exhibited either an equal or better efficacy than the tested antibiotic control, meropenem. This study highlights the possibility of G. mellonella larvae as an excellent in vivo model for investigating the host-pathogen interaction, including the efficacy of antimicrobials against MDR-EAEC strains.

Download Full-text

TMOD-09. CREATION OF A P53-INDEPENDENT IN VITRO AND IN VIVO MODEL SYSTEM FOR THE STUDY OF H3.1K27M DIPG

Neuro-Oncology ◽

10.1093/neuonc/noab196.870 ◽

2021 ◽

Vol 23 (Supplement_6) ◽

pp. vi217-vi217

Author(s):

Joseph Lagas ◽

Lihua Yang ◽

Oren Becher ◽

Joshua Rubin

Keyword(s):

Sex Difference ◽

High Grade Glioma ◽

Model System ◽

In Vivo Model ◽

Oligodendrocyte Progenitor Cells ◽

Cell Of Origin ◽

Founder Mutations ◽

Transgenic Mouse Line

Abstract Diffuse Intrinsic Pontine Glioma (DIPG) is a devastating pediatric high-grade glioma that occurs in the brainstem with a median survival of less than 1 year. A greater understanding of the early tumorigenic events is essential for the development of effective therapeutics. DIPG is characterized by founder mutations in histone H3, either H3.1K27M or H3.3K27M. These mutations cause global hypomethylation, resulting in aberrant gene expression. It is unknown how this mechanism contributes to tumorigenesis. Interestingly, H3.1K27M DIPG show an increased incidence in females, whereas H3.3K27M DIPG shows no sex difference. This illustrates that the tumorigenic potential of H3.1K27M may be different between the sexes. Few models of DIPG incorporate the study of H3.1K27M despite the fact that it represents a unique opportunity to obtain valuable information on the tumorigenesis of DIPG through the study of the sex difference. Thus, we have created an in vitro and in vivo model system for H3.1K27M DIPG utilizing the RCAS mouse model system. This system utilizes RCAS vectors and a RCAS-ntva transgenic mouse line to deliver specific mutations to nestin expressing cells in the brainstem, including oligodendrocyte progenitor cells (OPCs), the predicted cell of origin. Delivering H3.1K27M, ACVR1 R206H, and PDGFaa at postnatal day 7 produces DIPG-like tumors in vivo, confirmed by H and E staining, between 60 – 110 days post injection. Additionally, confirmed through immunofluorescence staining, we can isolate a pure population of OPCs via immunopanning and infect them with RCAS vectors in vitro to produce stable expression of H3.1K27M. Introduction of H3.1K27M alone into male and female OPC cultures provides an opportunity to compare the early tumorigenic effects of H3.1K27M between the sexes in vitro. These results demonstrate that we have created an in vitro and in vivo H3.1K27M DIPG model system for the study of sex differences and tumorigenesis in DIPG.

Download Full-text

The TRH Gene Is Regulated by Thyroid Hormone at the Level of Transcription in Vivo

Endocrine Reviews ◽

10.1210/edrv.31.1.9994 ◽

2010 ◽

Vol 31 (1) ◽

pp. 136-136

Author(s):

Michelle L. Sugrue ◽

Kristen R. Vella ◽

Crystal Morales ◽

Marisol E. Lopez ◽

Anthony N. Hollenberg

Keyword(s):

Thyroid Hormone ◽

Genomic Region ◽

Model System ◽

Model Systems ◽

In Vivo Model ◽

Pituitary Thyroid Axis ◽

Thyroid Axis ◽

Normal Production

ABSTRACT The expression of the TRH gene in the paraventricular nucleus (PVH) of the hypothalamus is required for the normal production of thyroid hormone (TH) in rodents and humans. In addition, the regulation of TRH mRNA expression by TH, specifically in the PVH, ensures tight control of the set point of the hypothalamic-pituitary-thyroid axis. Although many studies have assumed that the regulation of TRH expression by TH is at the level of transcription, there is little data available to demonstrate this. We used two in vivo model systems to show this. In the first model system, we developed an in situ hybridization (ISH) assay directed against TRH heteronuclear RNA to measure TRH transcription directly in vivo. We show that in the euthyroid state, TRH transcription is present both in the PVH and anterior/lateral hypothalamus. In the hypothyroid state, transcription is activated in the PVH only and can be shut off within 5 h by TH. In the second model system, we employed transgenic mice that express the Cre recombinase under the control of the genomic region containing the TRH gene. Remarkably, TH regulates Cre expression in these mice in the PVH only. Taken together, these data affirm that TH regulates TRH at the level of transcription in the PVH only and that genomic elements surrounding the TRH gene mediate its regulation by T3. Thus, it should be possible to identify the elements within the TRH locus that mediate its regulation by T3 using in vivo approaches.

Download Full-text

Abstract 4774: LC-MS/MS detection of the dansyl-modified biologically active CDK inhibitor VMY-1-103 using an in vivo model system

10.1158/1538-7445.am2012-4774 ◽

2012 ◽

Author(s):

Paul Sirajuddin ◽

Sudeep Das ◽

Lymor Ringer ◽

Patricia Salinas ◽

Olga Rodriguez ◽

...

Keyword(s):

Model System ◽

Biologically Active ◽

In Vivo Model ◽

Cdk Inhibitor ◽

Ms Detection

Download Full-text

Kindlin-1 Mutant Zebrafish as an In Vivo Model System to Study Adhesion Mechanisms in the Epidermis

Journal of Investigative Dermatology ◽

10.1038/jid.2013.154 ◽

2013 ◽

Vol 133 (9) ◽

pp. 2180-2190 ◽

Cited By ~ 11

Author(s):

Ruben Postel ◽

Coert Margadant ◽

Boris Fischer ◽

Maaike Kreft ◽

Hans Janssen ◽

...

Keyword(s):

Model System ◽

In Vivo Model

Download Full-text

The Thyrotropin-Releasing Hormone Gene Is Regulated by Thyroid Hormone at the Level of Transcription in Vivo

Endocrinology ◽

10.1210/en.2009-0976 ◽

2010 ◽

Vol 151 (2) ◽

pp. 793-801 ◽

Cited By ~ 36

Author(s):

Michelle L. Sugrue ◽

Kristen R. Vella ◽

Crystal Morales ◽

Marisol E. Lopez ◽

Anthony N. Hollenberg

Keyword(s):

Thyroid Hormone ◽

Genomic Region ◽

Model System ◽

Model Systems ◽

In Vivo Model ◽

Pituitary Thyroid Axis ◽

Thyroid Axis ◽

Normal Production

The expression of the TRH gene in the paraventricular nucleus (PVH) of the hypothalamus is required for the normal production of thyroid hormone (TH) in rodents and humans. In addition, the regulation of TRH mRNA expression by TH, specifically in the PVH, ensures tight control of the set point of the hypothalamic-pituitary-thyroid axis. Although many studies have assumed that the regulation of TRH expression by TH is at the level of transcription, there is little data available to demonstrate this. We used two in vivo model systems to show this. In the first model system, we developed an in situ hybridization (ISH) assay directed against TRH heteronuclear RNA to measure TRH transcription directly in vivo. We show that in the euthyroid state, TRH transcription is present both in the PVH and anterior/lateral hypothalamus. In the hypothyroid state, transcription is activated in the PVH only and can be shut off within 5 h by TH. In the second model system, we employed transgenic mice that express the Cre recombinase under the control of the genomic region containing the TRH gene. Remarkably, TH regulates Cre expression in these mice in the PVH only. Taken together, these data affirm that TH regulates TRH at the level of transcription in the PVH only and that genomic elements surrounding the TRH gene mediate its regulation by T3. Thus, it should be possible to identify the elements within the TRH locus that mediate its regulation by T3 using in vivo approaches.

Download Full-text

Effects, in an in-vivo model system, of 1,2,3,4-tetrahydroisoquinoline on glioma

Anti-Cancer Drugs ◽

10.1097/cad.0b013e32830d5887 ◽

2008 ◽

Vol 19 (9) ◽

pp. 859-870 ◽

Cited By ~ 5

Author(s):

Gyong-Suk Kang ◽

Xiang Di Wang ◽

Michael L. Mohler ◽

Oleg V. Kirichenko ◽

Renukadevi Patil ◽

...

Keyword(s):

Model System ◽

In Vivo Model

Download Full-text

A ‘tad’ of hope in the fight against airway disease

Biochemical Society Transactions ◽

10.1042/bst20200745 ◽

2020 ◽

Vol 48 (5) ◽

pp. 2347-2357

Author(s):

Eamon Dubaissi

Keyword(s):

Cell Types ◽

Airway Disease ◽

Live Imaging ◽

Model System ◽

In Vivo Model ◽

Large Airways ◽

Human Airways ◽

Tadpole Skin ◽

Mucociliary Epithelia

Xenopus tadpoles have emerged as a powerful in vivo model system to study mucociliary epithelia such as those found in the human airways. The tadpole skin has mucin-secreting cells, motile multi-ciliated cells, ionocytes (control local ionic homeostasis) and basal stem cells. This cellular architecture is very similar to the large airways of the human lungs and represents an easily accessible and experimentally tractable model system to explore the molecular details of mucociliary epithelia. Each of the cell types in the tadpole skin has a human equivalent and a conserved network of genes and signalling pathways for their differentiation has been discovered. Great insight into the function of each of the cell types has been achieved using the Xenopus model and this has enhanced our understanding of airway disease. This simple model has already had a profound impact on the field but, as molecular technologies (e.g. gene editing and live imaging) continue to develop apace, its use for understanding individual cell types and their interactions will likely increase. For example, its small size and genetic tractability make it an ideal model for live imaging of a mucociliary surface especially during environmental challenges such as infection. Further potential exists for the mimicking of human genetic mutations that directly cause airway disease and for the pre-screening of drugs against novel therapeutic targets.

Download Full-text

An in vivo model system for the study of avian osteoclast recruitment and activity

Bone and Mineral ◽

10.1016/0169-6009(90)90053-i ◽

1990 ◽

Vol 11 (2) ◽

pp. 127-140 ◽

Cited By ~ 11

Author(s):

David M. Webber ◽

David Menton ◽

Philip Osdoby

Keyword(s):

Model System ◽

In Vivo Model

Download Full-text