brainnet-europe.org). Moreover, a novel technology might allow the molecular imprinting of basal ganglia tissues obtained during deep brain stimulation (DBS) from living PD patients. Taking advantage of the temporary access to specific target regions during the implantation of DBS electrodes for PD treatment, the approach may allow the capture of small tissue amounts (i.e., about 20 μg of proteins) using a chemically modified micro silicon chip placed at the tip
of the surgical dilator, as demonstrated in monkeys [242]. If applicable to humans, the use of in vivo brain tissue imprints would reduce PMD Selleckchem Bioactive Compound Library to a few minutes avoiding protein degradation and may allow the observation of changes occurring early in PD course, although
control samples might be more difficult to obtain for comparisons. Finally, the great complexity and cellular heterogeneity characterizing human brain regions may be further addressed by additional cellular and subcellular fractionation steps. In the SN, mixed cell populations together with the characteristic neuronal DA loss in PD may have obscured the identification and quantification of subtle changes limited to DA neurons. Laser- capture microdissection (LCM) together with the emergence of more sensitive MS techniques and automated methods to collect cells offer now FDA approved Drug Library purchase the possibility to specifically isolate and investigate separately small defined areas including neurons, facilitating data interpretation. The selective dissection of DA neurons neurons by LCM might allow to dig deeper in the DA neuron proteome and to reveal the PJ34 HCl specific pathological mechanisms responsible for their demise in PD. Somewhat disappointingly, comparative proteomic studies have received little attention from the neuroscience community yet. This might be due to several factors including the absence of well- defined hypotheses and the low concordance rates observed between studies. It is generally difficult to compare proteomic studies together, as many sources of variability can drastically influence the final outcome. First, samples themselves are greatly heterogeneous,
as a consequence of patient’s history, co-morbidities, PD subtype, disease duration or therapies, all hardly controllable parameters. Tissue quality can also affect protein changes, when PMD delays are too long or different between groups. Second, the lack of standardized protocols for sample handling, preparation (i.e., dissection, solubilization buffers) and analysis may prevent inter-laboratory comparisons as well. In fact, the plethora of existing analytical methods may lead to variability in the identified proteome. This translates into small overlaps in protein identifications across proteomic studies. For example, more than 1200 nigral proteins of our recently identified dataset were not identified in the few other proteomic investigations studying SN [193], [195] and [196].