Submit Manuscript | http://medcraveonline.com Introduction Depression is a common and severe mental disorder, which can cause a considerable degree of disability to the individual and society. 1 The molecular mechanisms of depression are poorly understood even though many studies have been attempted. Moreover, there are currently no distinctive biological markers to aid in the diagnosis and treatment of depression. 2 The diagnosis, evaluation of medication effects, and prediction of relapse are carried out completely by clinical judgments based on the phenomenology of the disease. 1 The frst step requires identifying the molecular pathway for depression. Genomic approaches have attempted to fnd the underlying molecular pathways, but have not successfully identifed the major genes for depression. 3 This may be because there are multiple genes working together or interacting with the environment in a very complex way. 1–3 Although this genomic information is important, it does not account for the important environmental infuences on illness onset, and the presence of a gene does not necessarily refect functioning protein expression in vivo. 4 Many studies indicate that the proteins acts as biomarkers play role in the diagnosis of depression. Serum brain-derived neurotrophic factor (BDNF) would be the most studied protein. 5,6 A recent meta-analyses on 179 association studies concluded that serum BDNF concentrations were lower in untreated depressed patients than healthy control and antidepressant treated patients. 7 . However, one or two protein biomarkers are insuffcient to diagnose MDD because proteins usually function in several networks rather than alone. The study of the total set of expressed proteins by a cell, tissue or organism at a given time under a determined condition. 8 Proteomics is basically the study of expression of the protein that is present in any individual that play particular role in the maintenance of the body functions. Proteomics play a vital role in the diagnoses of the alternation in the genetic makeup of the organism that exist in case of the particular disease state. 9 Dynamic proteomic research used fuorescence difference gel electrophoresis, found 42 changed proteins in the liver of chronic restraint stressed rats and validated 3 proteins to suggest how functional proteins act on metabolites to produce energy and process materials. More evidences have shown that stress may have an effect on liver .Proteomic techniques based on Isobaric Tags for Relative and Absolute Quantifcation [ITRAQ], labeling and liquid chromatography-mass spectrometry [LC-MS] provide a high- throughput approach to analyze differentially expressed proteins in various physiological and pathological states. 9 Therefore, it is necessary to identify a set of proteins as a biomarker, and proteomics is the most powerful tool to develop a novel biomarker set. Proteomics has diagnostic advantages over genomics because it can refect post-translational events. The study of total set of proteins expressed by the organism is referred as proteomics which includes gene to gene, gene-environmental interaction and post-translational modifcations as well. Proteomics provides the basic information to study the expression of sets of genes that have different infuence on the mood variation. In this review, we mentioned some biomarkers that play role in the identifcation of the depression by analyzing the proteomics in the patients which indicates the variation in the original genetic sequence of the proteins led to the depression. Biomarkers Biomarkers are the substances that play role in the identifcation of the presence and absence of the disease condition, predict treatment responses. These biomarkers act as a marker to mark the alternation in the original sequence of the gene and distinguish the abnormal disease condition from the healthy normal condition. Bio markers are basically the substance that interact the biological system with the hazardious thing which may be chemical, environmental agent and biological substances as well. 10 Here some biomarkers are given below used in depression: Oligodendrocytes Oligodendrocytes are the cells present in the brain that play role in the myelination of axons in the central nerveous system. Destruction and alternation in the oligodendrocytes results in the malformation of the myelin sheath that lead to the decrease rate of propagation of the nerve impulse and leakages at the axonal site that particularly destroy the signaling mechanism of the nerve impulse. Dysfuntion of the oligodendrocytes results in the neuronal disorders like schizopherenia etc. Oligodendrocytes are involved in the shortening of the telomere and cause loses of some genes which can be a cause of depression. 11 Mylinated nerve fbers are in case of traumatic brain injury are lost and continue after the post traumatic phase. It cause the damage of oligodendrocytes and the myelinated sheath that is formed by the MOJ Proteomics Bioinform. 2017;6(2):230‒234. 230 © 2017 Samad et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and build upon your work non-commercially. A review on diagnostic proteomics of depression Volume 6 Issue 2 - 2017 Noreen Samad, Sadia Jabeen, Zainab Javeed, Nafeesa Jamil, Sadia Bibi, Zaitoon Ghani, Uzma Amin Department of Biochemistry, Bahauddin Zakariya University, Pakistan Correspondence: Noreen Samad, Assistant Professor, Department of Biochemistry, Bahauddin Zakariya University, Multan, Pakistan, Email Noreen.samad@bzu.edu.pk Received: July 28, 2017 | Published: September 08, 2017 Abstract Depression is the psychiatric disorder cause when deviation occurs from the standard proteomic condition in individuals. Pathogenesis and etiology of psychiatric disorders are still not clear and many signaling pathways are unknown. In that case the gene provides the primary information about expression of gene and activities of brain. This review focused on the diagnostic proteomics of depression by means of biomarkers. Evidences suggested that reduced and elevated levels of these biomarkers involved in the pathology of depression. These biomarkers could not be used for the diagnostic purposes but also used for the therapeutics. The aim of this non-systematic review article is to evaluate and document a potential importance of proteomics in diagnosis of depression. Keywords: biomarkers, proteomics, depression, pathology, proteomic, genomic MOJ Proteomics & Bioinformatics Review Article Open Access