Protein Extraction and Sample Preparation Methods for Shotgun Proteomics with Central Nervous System Cells and Brain Tissue.

Shotgun proteomics based in mass spectrometry has been extensively utilized to investigate biological samples for basic and applied research in the clinical field to elucidate changes in the molecular mechanisms caused by diseases. There is still a great lack of information about the molecular mechanisms and the origins of most brain disorders, which makes shotgun proteomics an interesting tool in the study of these diseases. A wide range of samples can be used to study such diseases, such as cerebrospinal fluid, central nervous system cells, and brain tissue via postmortem analysis. As such, different protein extraction methods must be applied to achieve the best results for each sample type. The lysis buffer, digestion protocol, and peptide purification steps chosen prior to liquid chromatography-mass spectrometry analyses are essential to obtain reliable proteomic datasets. For this reason, the availability of a list with a variety of methods and a description of the pros and cons for each one has been compiled and elaborated upon. This review presents several methods for protein extraction, protein digestion, and sample cleanup with a focus on shotgun proteomics via mass spectrometry and a further focus on studying brain disorders.