Human diseases associated with defects in assembly of OXPHOS complexes

The structural biogenesis and functional proficiency of the multiheteromeric complexes forming the mitochondrial oxidative phosphorylation system (OXPHOS) require the concerted action of a number of chaperones and other assembly factors, most of which are specific for each complex. Mutations in a large number of these assembly factors are responsible for mitochondrial disorders, in most cases of infantile onset, typically characterized by biochemical defects of single specific complexes. In fact, pathogenic mutations in complex-specific assembly factors outnumber, in many cases, the repertoire of mutations found in structural subunits of specific complexes. The identification of patients with specific defects in assembly factors has provided an important contribution to the nosological characterization of mitochondrial disorders, and has also been a crucial means to identify a huge number of these proteins in humans, which play an essential role in mitochondrial bioenergetics. The wide use of next generation sequencing (NGS) has led to and will allow the identifcation of additional components of the assembly machinery of individual complexes, mutations of which are responsible for human disorders. The functional studies on patients’ specimens, together with the creation and characterization of in vivo models, are fundamental to better understand the mechanisms of each of them. A new chapter in this field will be, in the near future, the discovery of mechanisms and actions underlying the formation of supercomplexes, molecular structures formed by the physical, and possibly functional, interaction of some of the individual respiratory complexes, particularly complex I (CI), III (CIII), and IV (CIV).

Download Full-text

Molecular and Functional Characterization of Circulating Tumor Cells: From Discovery to Clinical Application

Clinical Chemistry ◽

10.1373/clinchem.2019.303586 ◽

2019 ◽

Vol 66 (1) ◽

pp. 97-104 ◽

Cited By ~ 10

Author(s):

Luis Enrique Cortés-Hernández ◽

Zahra Eslami-S ◽

Klaus Pantel ◽

Catherine Alix-Panabières

Keyword(s):

Tumor Cells ◽

Circulating Tumor Cells ◽

Liquid Biopsy ◽

Functional Characterization ◽

Clinical Information ◽

In Vivo Models ◽

Functional Studies

Abstract BACKGROUND One of the objectives for the liquid biopsy is to become a surrogate to tissue biopsies in diagnosis of cancer as a minimally invasive method, with clinical utility in real-time follow-ups of patients. To achieve this goal, it is still necessary to achieve a better understanding of the mechanisms of cancer and the biological principles that govern its behavior, particularly with regard to circulating tumor cells (CTCs). CONTENT The isolation, enumeration, detection, and characterization of CTCs have already proven to provide relevant clinical information about patient prognosis and treatment prediction. Moreover, CTCs can be analyzed at the genome, proteome, transcriptome, and secretome levels and can also be used for functional studies in in vitro and in vivo models. These features, taken together, have made CTCs a very valuable biosource. SUMMARY To further advance the field and discover new clinical applications for CTCs, several studies have been performed to learn more about these cells and better understand the biology of metastasis. In this review, we describe the recent literature on the topic of liquid biopsy with particular focus on the biology of CTCs.

Download Full-text

Preclinical Testing of Radiopharmaceuticals for the Detection and Characterization of Osteomyelitis: Experiences from a Porcine Model

Molecules ◽

10.3390/molecules26144221 ◽

2021 ◽

Vol 26 (14) ◽

pp. 4221

Author(s):

Aage Kristian Olsen Alstrup ◽

Svend Borup Jensen ◽

Ole Lerberg Nielsen ◽

Lars Jødal ◽

Pia Afzelius

Keyword(s):

Animal Model ◽

Animal Models ◽

Porcine Model ◽

Animal Experiments ◽

Radioactive Tracers ◽

The Individual ◽

Selection Of

The development of new and better radioactive tracers capable of detecting and characterizing osteomyelitis is an ongoing process, mainly because available tracers lack selectivity towards osteomyelitis. An integrated part of developing new tracers is the performance of in vivo tests using appropriate animal models. The available animal models for osteomyelitis are also far from ideal. Therefore, developing improved animal osteomyelitis models is as important as developing new radioactive tracers. We recently published a review on radioactive tracers. In this review, we only present and discuss osteomyelitis models. Three ethical aspects (3R) are essential when exposing experimental animals to infections. Thus, we should perform experiments in vitro rather than in vivo (Replacement), use as few animals as possible (Reduction), and impose as little pain on the animal as possible (Refinement). The gain for humans should by far exceed the disadvantages for the individual experimental animal. To this end, the translational value of animal experiments is crucial. We therefore need a robust and well-characterized animal model to evaluate new osteomyelitis tracers to be sure that unpredicted variation in the animal model does not lead to a misinterpretation of the tracer behavior. In this review, we focus on how the development of radioactive tracers relies heavily on the selection of a reliable animal model, and we base the discussions on our own experience with a porcine model.

Download Full-text

Two Decades of Triazine Dendrimers

Molecules ◽

10.3390/molecules26164774 ◽

2021 ◽

Vol 26 (16) ◽

pp. 4774

Author(s):

Eric E. Simanek

Keyword(s):

Genetic Material ◽

Structural Complexity ◽

Bioactive Molecules ◽

Bioactive Materials ◽

In Vivo Models ◽

Tumor Subtypes ◽

Gas Streams

For two decades, methods for the synthesis and characterization of dendrimers based on [1,3,5]-triazine have been advanced by the group. Motivated by the desire to generate structural complexity on the periphery, initial efforts focused on convergent syntheses, which yielded pure materials to generation three. To obtain larger generations of dendrimers, divergent strategies were pursued using iterative reactions of monomers, sequential additions of triazine and diamines, and ultimately, macromonomers. Strategies for the incorporation of bioactive molecules using non-covalent and covalent strategies have been explored. These bioactive materials included small molecule drugs, peptides, and genetic material. In some cases, these constructs were examined in both in vitro and in vivo models with a focus on targeting prostate tumor subtypes with paclitaxel conjugates. In the materials realm, the use of triazine dendrimers anchored on solid surfaces including smectite clay, silica, mesoporous alumina, polystyrene, and others was explored for the separation of volatile organics from gas streams or the sequestration of atrazine from solution. The combination of these organics with metal nanoparticles has been probed. The goal of this review is to summarize these efforts.

Download Full-text

Characterization of the Potent, Selective Nrf2 Activator, 3-(Pyridin-3-Ylsulfonyl)-5-(Trifluoromethyl)-2H-Chromen-2-One, in Cellular and In Vivo Models of Pulmonary Oxidative Stress

Journal of Pharmacology and Experimental Therapeutics ◽

10.1124/jpet.117.241794 ◽

2017 ◽

Vol 363 (1) ◽

pp. 114-125 ◽

Cited By ~ 9

Author(s):

John G. Yonchuk ◽

Joseph P. Foley ◽

Brian J. Bolognese ◽

Gregory Logan ◽

William E. Wixted ◽

...

Keyword(s):

Oxidative Stress ◽

In Vivo Models ◽

Nrf2 Activator

Download Full-text

Proteomic and 3D structure analyses highlight the C/D box snoRNP assembly mechanism and its control

The Journal of Cell Biology ◽

10.1083/jcb.201404160 ◽

2014 ◽

Vol 207 (4) ◽

pp. 463-480 ◽

Cited By ~ 35

Author(s):

Jonathan Bizarro ◽

Christophe Charron ◽

Séverine Boulon ◽

Belinda Westman ◽

Bérengère Pradet-Balade ◽

...

Keyword(s):

Isotope Labeling ◽

Core Protein ◽

3D Structure ◽

Assembly Mechanism ◽

Core Proteins ◽

Assembly Factors ◽

Assembly Factor

In vitro, assembly of box C/D small nucleolar ribonucleoproteins (snoRNPs) involves the sequential recruitment of core proteins to snoRNAs. In vivo, however, assembly factors are required (NUFIP, BCD1, and the HSP90–R2TP complex), and it is unknown whether a similar sequential scheme applies. In this paper, we describe systematic quantitative stable isotope labeling by amino acids in cell culture proteomic experiments and the crystal structure of the core protein Snu13p/15.5K bound to a fragment of the assembly factor Rsa1p/NUFIP. This revealed several unexpected features: (a) the existence of a protein-only pre-snoRNP complex containing five assembly factors and two core proteins, 15.5K and Nop58; (b) the characterization of ZNHIT3, which is present in the protein-only complex but gets released upon binding to C/D snoRNAs; (c) the dynamics of the R2TP complex, which appears to load/unload RuvBL AAA+ adenosine triphosphatase from pre-snoRNPs; and (d) a potential mechanism for preventing premature activation of snoRNP catalytic activity. These data provide a framework for understanding the assembly of box C/D snoRNPs.

Download Full-text

Functional Studies on Viable Circulating Tumor Cells

Clinical Chemistry ◽

10.1373/clinchem.2015.242537 ◽

2016 ◽

Vol 62 (2) ◽

pp. 328-334 ◽

Cited By ~ 53

Author(s):

Klaus Pantel ◽

Catherine Alix-Panabières

Keyword(s):

Cancer Patients ◽

Tumor Cells ◽

Circulating Tumor Cells ◽

Cancer Diagnostics ◽

Published Data ◽

Liquid Biopsies ◽

In Vivo Models ◽

Functional Studies

AbstractBACKGROUNDResearch on circulating tumor cells (CTCs) as new biomarkers has received great attention over the past decade. In particular, the capture and analysis of CTCs as “liquid biopsies” provides the possibility to avoid invasive tissue biopsies, with obvious implications in cancer diagnostics.CONTENTThe focus of this review is to describe and discuss how functional studies on viable CTCs can enlarge the spectrum of applications of liquid biopsies, with emphasis on breast, prostate, colon, and lung cancer as the major tumor entities in industrialized countries. The low number of CTCs in the peripheral blood of most cancer patients makes challenging the in vitro culture of CTCs. Epithelial tumor cells are difficult to culture, even when starting with millions of tumor cells. Recently, several groups have achieved important advances in the in vitro and in vivo expansion of CTCs from cancer patients at very advanced stages with higher amounts of CTCs. Here, we present current technologies to enrich and detect viable human CTCs, including positive and negative enrichment strategies that are based on antigen expression and physical properties of CTCs. We also discuss published data about functional studies on CTCs that use in vitro and in vivo models.SUMMARYFunctional analyses on CTCs offer the possibility to identify the biological properties of metastatic cells, including the identification of metastasis-initiating cells. Moreover, CTC-derived cell lines and xenografts might reveal new therapeutic targets and can be used for drug screening.

Download Full-text

Identification and characterization of T reg–like cells in zebrafish

Journal of Experimental Medicine ◽

10.1084/jem.20162084 ◽

2017 ◽

Vol 214 (12) ◽

pp. 3519-3530 ◽

Cited By ~ 26

Author(s):

Melissa Kasheta ◽

Corrie A. Painter ◽

Finola E. Moore ◽

Riadh Lobbardi ◽

Alysia Bryll ◽

...

Keyword(s):

T Lymphocytes ◽

Live Cell Imaging ◽

Genetic Ablation ◽

Functional Studies ◽

Normal Functions ◽

Inflammatory Phenotype ◽

Identification And Characterization

Regulatory T (T reg) cells are a specialized sublineage of T lymphocytes that suppress autoreactive T cells. Functional studies of T reg cells in vitro have defined multiple suppression mechanisms, and studies of T reg–deficient humans and mice have made clear the important role that these cells play in preventing autoimmunity. However, many questions remain about how T reg cells act in vivo. Specifically, it is not clear which suppression mechanisms are most important, where T reg cells act, and how they get there. To begin to address these issues, we sought to identify T reg cells in zebrafish, a model system that provides unparalleled advantages in live-cell imaging and high-throughput genetic analyses. Using a FOXP3 orthologue as a marker, we identified CD4-enriched, mature T lymphocytes with properties of T reg cells. Zebrafish mutant for foxp3a displayed excess T lymphocytes, splenomegaly, and a profound inflammatory phenotype that was suppressed by genetic ablation of lymphocytes. This study identifies T reg–like cells in zebrafish, providing both a model to study the normal functions of these cells in vivo and mutants to explore the consequences of their loss.

Download Full-text