Are being developed for systems biology. We will also consider how

Are being developed for systems biology. We will also consider how complex human diseases and pharmacology benefit from systems-based approaches. Finally, we will discuss the evolution of systems biology and the early phases of systems medicine in the context of aiding physicians in addressing human disease complexity and, ultimately, improving clinical practice for patients.Author Manuscript Author Manuscript Author Manuscript Author ManuscriptHIGH-THROUGHPUT TECHNOLOGIES DRIVING SYSTEMS BIOLOGYA complex system is composed of a large number of interconnected components whose interplay accounts for a variety of system functions. A key factor that promoted the emergence of systems biology is the CBIC2 site development of various high-throughput technologies. These biotechnologies not only allow quantification of individual components (e.g., genes, proteins, microRNAs, and metabolites) of a biological system, but also afford the generation of massive interactomes describing the complex interactions of these components, and even decipher the function of the system. DNA sequencing techniques determine the complete DNA sequence of an organism’s genome and the entire set of genes at a single time. Moreover, next-generation sequencing (NGS) now can generate DNA sequences of many organisms at a very low cost 4. Geneexpression microarray allows global quantification of mRNA transcripts of thousands of genes 3. Furthermore, NGS-based RNA sequencing (RNA-seq) can not only be used to measure gene expression levels at a higher resolution and sample throughput, but also can reveal alternative gene spliced transcripts 6. For example, Gene Expression Omnibus (GEO) and other database repositories store massive microarray- and sequence-based gene expression datasets that can be reused as a basis for new biological studies 19. Similarly, mass spectrometry (MS) and isobaric tags for relative and absolute quantification (iTRAQ) can be used to determine the concentration of thousands of proteins in a single experiment 20, 21. The Human Protein Atlas (www.proteinatlas.org) contains immunohistochemistry-based maps of protein expression and localization profiles for a large majority of all human protein-coding genes based on both RNA and protein data in normal tissue, cancer, GW9662MedChemExpress GW9662 subcellular organelles, and cell lines 22, 23. Such datasets offer the possibility to explore tissue-specific proteomes and analyze tissue profiles for specific protein classes. Global metabolomic profiling by nuclear magnetic resonance (NMR) and liquid chromatography (LC) or gas chromatography (GC) coupled with MS is used to measure the composition and concentration of both targeted and untargeted metabolites 24. In particular, mass cytometry facilitates high-dimensional quantitative analysis of the effects of molecules at single-cell resolution 25. Such single-cell genomic analyses greatly enhance diagnostic and experimental analyses. Experimental data generated by these biotechnologies represent the levels or abundance of individual biological elements and have been deposited in major databases, as listed in Table 1.Wiley Interdiscip Rev Syst Biol Med. Author manuscript; available in PMC 2016 July 01.Wang et al.PageThere are also biotechnologies that can detect the interactions between biological elements in a high-throughput manner. For example, chromatin immunoprecipitation assay (ChIP) is a technology that utilizes DNA microarray technology for investigating interactions between proteins and D.Are being developed for systems biology. We will also consider how complex human diseases and pharmacology benefit from systems-based approaches. Finally, we will discuss the evolution of systems biology and the early phases of systems medicine in the context of aiding physicians in addressing human disease complexity and, ultimately, improving clinical practice for patients.Author Manuscript Author Manuscript Author Manuscript Author ManuscriptHIGH-THROUGHPUT TECHNOLOGIES DRIVING SYSTEMS BIOLOGYA complex system is composed of a large number of interconnected components whose interplay accounts for a variety of system functions. A key factor that promoted the emergence of systems biology is the development of various high-throughput technologies. These biotechnologies not only allow quantification of individual components (e.g., genes, proteins, microRNAs, and metabolites) of a biological system, but also afford the generation of massive interactomes describing the complex interactions of these components, and even decipher the function of the system. DNA sequencing techniques determine the complete DNA sequence of an organism’s genome and the entire set of genes at a single time. Moreover, next-generation sequencing (NGS) now can generate DNA sequences of many organisms at a very low cost 4. Geneexpression microarray allows global quantification of mRNA transcripts of thousands of genes 3. Furthermore, NGS-based RNA sequencing (RNA-seq) can not only be used to measure gene expression levels at a higher resolution and sample throughput, but also can reveal alternative gene spliced transcripts 6. For example, Gene Expression Omnibus (GEO) and other database repositories store massive microarray- and sequence-based gene expression datasets that can be reused as a basis for new biological studies 19. Similarly, mass spectrometry (MS) and isobaric tags for relative and absolute quantification (iTRAQ) can be used to determine the concentration of thousands of proteins in a single experiment 20, 21. The Human Protein Atlas (www.proteinatlas.org) contains immunohistochemistry-based maps of protein expression and localization profiles for a large majority of all human protein-coding genes based on both RNA and protein data in normal tissue, cancer, subcellular organelles, and cell lines 22, 23. Such datasets offer the possibility to explore tissue-specific proteomes and analyze tissue profiles for specific protein classes. Global metabolomic profiling by nuclear magnetic resonance (NMR) and liquid chromatography (LC) or gas chromatography (GC) coupled with MS is used to measure the composition and concentration of both targeted and untargeted metabolites 24. In particular, mass cytometry facilitates high-dimensional quantitative analysis of the effects of molecules at single-cell resolution 25. Such single-cell genomic analyses greatly enhance diagnostic and experimental analyses. Experimental data generated by these biotechnologies represent the levels or abundance of individual biological elements and have been deposited in major databases, as listed in Table 1.Wiley Interdiscip Rev Syst Biol Med. Author manuscript; available in PMC 2016 July 01.Wang et al.PageThere are also biotechnologies that can detect the interactions between biological elements in a high-throughput manner. For example, chromatin immunoprecipitation assay (ChIP) is a technology that utilizes DNA microarray technology for investigating interactions between proteins and D.