Panga Jaipal Reddy

Proteomic technologies for the identification of disease biomarkers in serum: Advances and challenges ahead†

Serum is an ideal biological sample that contains an archive of information due to the presence of a variety of proteins released by diseased tissue, and serum proteomics has gained considerable interest for the disease biomarker discovery. Easy accessibility and rapid protein changes in response to disease pathogenesis makes serum an attractive sample for clinical research. Despite these advantages, the analysis of serum proteome is very challenging due to the wide dynamic range of proteins, difficulty in finding low‐abundance target analytes due to the presence of high‐abundance serum proteins, high levels of salts and other interfering compounds, variations among individuals and paucity of reproducibility. Sample preparation introduces pre‐analytical variations and poses major challenges to analyze the serum proteome. The label‐free detection techniques such as surface plasmon resonance, microcantilever, few nanotechniques and different resonators are rapidly emerging for the analysis of serum proteome and they have exhibited potential to overcome few limitations of the conventional techniques. In this article, we will discuss the current status of serum proteome analysis for the biomarker discovery and address key technological advancements, with a focus on challenges and amenable solutions.

Protein microarrays and novel detection platforms.

The field of proteomics has undergone rapid advancements over the last decade and protein microarrays have emerged as a promising technological platform for the challenging task of studying complex proteomes. This gel-free approach has found an increasing number of applications due to its ability to rapidly and efficiently study thousands of proteins simultaneously. Different protein microarrays, including capture arrays, reverse-phase arrays, tissue microarrays, lectin microarrays and cell-free expression microarrays, have emerged, which have demonstrated numerous applications for proteomics studies including biomarker discovery, protein interaction studies, enzyme–substrate profiling, immunological profiling and vaccine development, among many others. The need to detect extremely low-abundance proteins in complex mixtures has provided motivation for the development of sensitive, real-time and multiplexed detection platforms. Conventional label-based approaches like fluorescence, chemiluminescence and use of radioactive isotopes have witnessed substantial advancements, with techniques like quantum dots, gold nanoparticles, dye-doped nanoparticles and several bead-based methods now being employed for protein microarray studies. In order to overcome the limitations posed by label-based technologies, several label-free approaches like surface plasmon resonance, carbon nanotubes and nanowires, and microcantilevers, among others, have also advanced in recent years, and these methods detect the query molecule itself. The scope of this article is to outline the protein microarray techniques that are currently being used for analytical and function-based proteomics and to provide a detailed analysis of the key technological advances and applications of various detection systems that are commonly used with microarrays.

A Simple Protein Extraction Method for Proteomic Analysis of Diverse Biological Specimens

The success of a proteomic experiment largely depends on the quality and quantity of the protein extract. Currently, various protocols are available for extraction of proteins from different types of samples; however, further optimization is required for every new sample type. Hence, a common protein extraction protocol is desirable. In the present study, soluble proteins were extracted from six diverse samples using TRIzol without any additional clean-up step and subjected to 2-DE and 2D-DIGE analysis for global protein expression profiling. Image analysis using IMP7 and DeCyder showed good coverage, reproducibility and quality of the gel. MS analysis of 24 spots from all the six samples showed good score and coverage for the identified proteins. Additionally, this method facilitated the concurrent isolation of RNA from the same cell lysates with high integrity and quality, suitable for transcriptomic analysis. Thus, we demonstrate the use of a common protein extraction protocol involving TRIzol reagent for 2-DE, 2D-DIGE and MS analysis using six diverse samples and show its suitability for concomitant transcriptomic studies.

Virtual Labs in proteomics: new E-learning tools.

Web-based educational resources have gained enormous popularity recently and are increasingly becoming a part of modern educational systems. Virtual Labs are E-learning platforms where learners can gain the experience of practical experimentation without any direct physical involvement on real bench work. They use computerized simulations, models, videos, animations and other instructional technologies to create interactive content. Proteomics being one of the most rapidly growing fields of the biological sciences is now an important part of college and university curriculums. Consequently, many E-learning programs have started incorporating the theoretical and practical aspects of different proteomic techniques as an element of their course work in the form of Video Lectures and Virtual Labs. To this end, recently we have developed a Virtual Proteomics Lab at the Indian Institute of Technology Bombay, which demonstrates different proteomics techniques, including basic and advanced gel and MS-based protein separation and identification techniques, bioinformatics tools and molecular docking methods, and their applications in different biological samples. This Tutorial will discuss the prominent Virtual Labs featuring proteomics content, including the Virtual Proteomics Lab of IIT-Bombay, and E-resources available for proteomics study that are striving to make proteomic techniques and concepts available and accessible to the student and research community. This Tutorial is part of the International Proteomics Tutorial Programme (IPTP 14). Details can be found at: http://www.proteomicstutorials.org/.

Towards an Ecology of Collective Innovation: Human Variome Project (HVP), Rare Disease Consortium for Autosomal Loci (RaDiCAL) and Data-Enabled Life Sciences Alliance (DELSA).

The Millennium Summit in 2000 established the Millennium Development Goals (MDGs), which were agreed upon by 193 countries and 23 international organizations to combat extreme poverty and other pressing global priorities for human development. In the December 2011 issue of CPPM, Borda-Rodriguez and Huzair present an analysis of the close ties and synergies among the MDGs, pharmacogenomics and personalized medicine. Notably, MDGs promote the creation of collective innovation, a concept with both substantive and instrumental pertinence for the personalized medicine R&D that is currently undergoing rapid globalization. The ethos for collective innovation in global health is also embodied in the Paris Declaration on Aid Effectiveness, endorsed in 2005 by more than 100 signatories, including donor and developing country governments, regional development banks and international aid agencies.

Cancer Biomarker Detection by Surface Plasmon Resonance Biosensors

Diagnosis of cancer at an early stage of development is essential for effective treatment to control its progression and reduce the mortality rate. Biomarkers are useful candidates for disease diagnosis, monitoring disease progression, and following prognosis in response to the therapeutic interventions. Over the last decade here has been a growing interest in analysis of various biological fluids to identify anels of protein markers for cancer, leading to the discovery of several potential argets. Despite the sincere efforts from various research groups from all over the world, only a handful of the identified candidates has been approved by the US Food and Drug Administration, which indicates serious “bottle neck” between the “benchside” findings and their successful “bed-side” implications. Multiple issues associated with candidate markers, such as very low abundance, ambiguity, lack of specificity, enormous variation among individuals, and paucity of reproducibility, are hindering their successful translation in clinics. Several proteomic approaches, such as mass spectrometry-based assays, gelased profiling, and, more recently, protein and antibody arrays, are emerging rapidly as advanced platforms for cancer biomarker discovery and have enhanced our understanding of biological networks at the functional level to provide some mechanistic insight into this fatal disease. However, limited dynamic range and low sensitivity are the major limitations for most of the existing gel and MS-based proteomic approaches. Moreover, accurate diagnosis of complex diseases like ancer requires the simultaneous detection of multiple biomarkers, stipulating the eed for high-throughput (HT) detection platforms. To this end, array-based aproaches, such as antibody, reverse phase, and functional microarrays, are promising

Personalized Medicine in the Age of Pharmacoproteomics: A Close up on India and Need for Social Science Engagement for Responsible Innovation in Post-Proteomic Biology

“Because DNA sequencing technology is inherently simpler and more scalable than protein analytical technology, and because the finiteness of genomes invited a spirit of rapid conquest, the notion of genome sequencing has displaced that of protein databases in the minds of most molecular biologists for the last decade…As proteomics now takes center stage in molecular biology, it is appropriate to take stock of progress to date and consider the major strategic objectives that can be achieved during the next stages of its evolution”.

A comprehensive proteomic analysis of totarol induced alterations in Bacillus subtilis by multipronged quantitative proteomics

UNLABELLED The rapid emergence of microbial drug resistance indicates the urgent need for development of new antimicrobial agents. Bacterial cell division machinery is considered as a promising antimicrobial target. Totarol is a naturally existing diterpenoid, which has the ability to restrain bacterial growth by perturbing the cell division. The present study was conducted to investigate the proteomic alterations in Bacillus subtilis as a consequence of totarol treatment to decipher its mechanism of action and possible molecular targets. Cellular proteome of the totarol treated B. subtilis AH75 strain was analyzed by using multiple complementary proteomic approaches. After the drug treatment, 12, 38 and 139 differentially expressed (1.5 fold change) proteins were identified using 2-DE, DIGE and iTRAQ analyses, respectively. In silico functional analysis of the identified differentially expressed proteins indicated a possible effect of totarol on the central metabolism for energy production, heme biosynthesis and chemotaxis. Interestingly, the primary dehydrogenases, which play a vital role in generating the reducing equivalent, were found to be repressed after totarol treatment indicating an apparent metabolic shutdown. Consequently, multiple cellular assays including resazurin assay and FACS analysis of 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) staining confirmed the effect of totarol on respiratory activity and cellular metabolism. BIOLOGICAL SIGNIFICANCE The exact mechanism of action of totarol is still unclear and further investigations are essential to identify the molecular/cellular targets of this potential antimicrobial agent. The present study demonstrates the application of differential proteome to decipher the mechanism of action and molecular targets of totarol in B. subtilis. Our quantitative proteome analysis revealed that totarol induced alterations in the expression levels of 139 proteins (1.5 fold change and ≥2 peptides) in B. subtilis. Findings obtained from this study indicate that totarol treatment leads to metabolic shutdown by repressing the major central metabolic dehydrogenases in B. subtilis. In addition, expression levels of universal chaperone proteins, heme biosynthesis, and ribosomal proteins were found to be altered, which caused the filamentation of the bacteria. To the best of our knowledge, this is the foremost inclusive investigation describing totarol induced alterations in B. subtilis proteome and diverse physiological processes. We anticipate that this in depth proteomic study may contribute to a better understanding of the mode of action of totarol and its primary molecular and cellular targets.

Proteomics Analyses of Bacillus subtilis after Treatment with Plumbagin, a Plant-Derived Naphthoquinone

Infectious diseases and increasing antibiotic resistance among diverse classes of microbes are global health concerns and a prime focus of omics systems science applications in novel drug discovery. Plumbagin is a plant-derived naphthoquinone, a natural product that exhibits antibacterial activity against gram-positive bacteria. In the present study, we investigated the antimicrobial effects of plumbagin against Bacillus subtilis using two complementary proteomics techniques: two-dimensional electrophoresis (2-DE) and isobaric tag for relative and absolute quantification (iTRAQ). Comparative quantitative proteomics analysis of plumbagin treated and untreated control samples identified differential expression of 230 proteins (1% FDR, 1.5 fold-change and ≥2 peptides) in B. subtilis after plumbagin treatment. Pathway analysis involving the differentially expressed proteins suggested that plumbagin effectively increases heme and protein biosynthesis, whereas fatty acid synthesis was significantly reduced. Gene expression and metabolic activity assays further corroborated the proteomics findings. We anticipate that plumbagin blocks the cell division by altering the membrane permeability required for energy generation. This is the first report, to the best of our knowledge, offering new insights, at proteome level, for the putative mode(s) of action of plumbagin and attendant cellular targets in B. subtilis. The findings also suggest new ways forward for the modern omics-guided drug target discovery, building on traditional plant medicine.

Global proteomic profiling identifies etoposide chemoresistance markers in non-small cell lung carcinoma.

UNLABELLED Chemoresistance is one of the leading health concerns in cancer treatment. Understanding the mechanism of chemoresistance is the best way to improve the survival of the patient. Etoposide and its analogues are widely used as antitumor drugs in lung cancer but many etoposide resistant lung cancer cases has been identified in recent years. The present study aims to explore the cellular response of lung cancer cell lines to etoposide and finding the potential chemoresistant marker proteins. Multiple proteomic platforms like 2-DE, DIGE and iTRAQ have been used to study the global proteome profile of NCI-H460 and etoposide resistant NCI-H460R cell lines. Our study revealed that etoposide treatment leads to alteration of 83 proteins in NCI-H460R cell lines. The functional analysis highlighted the role of the differential expressed proteins in cellular signaling, apoptosis, and cytoskeleton reorganization. Our study has identified several new proteins like RHOC, DLG5, UGDH, TMOD3 in addition to known chemoresistance associated proteins. In silico prediction of the important selected candidates are further validated at protein and mRNA level. Further, functional studies of newly identified candidate genes RHOC and DLG5 revealed that chemotherapeutic resistance is associated with their elevated level and may serve as novel targets for therapeutic intervention. BIOLOGICAL SIGNIFICANCE Etoposide and its analogues have been used for lung cancer treatment for a while and it was reported that many non small cell lung carcinoma patients are resistant to etoposide. Although etoposide show drug resistance, the exact mechanism was not well understood. The present study focused on the global proteome analysis of NCI-H460 and NCI-H460R cell lines using multiple proteomic platforms to understand the potential chemoresistant markers for etoposide. Our multi-proteomic analysis has showed differential expression of 83 proteins involved in oxidative phosphorylation, metabolic, protein folding, cytoskeleton associated protein along with apoptotic pathway has been identified. In addition, quite a few interesting proteins such as RHOC, DLG5, HSP90, citrate synthase, UDP-glucose-6-dehydrogenase, Tropomodulin-3 are involved in chemoresistance has been observed. Overall, this is the first comprehensive proteomic study on etoposide resistant cell line NCI-H460 to explore the mechanism of chemoresistance in lung cancer.