D description of your CPP internalization mechanisms, and also other properties like stability, toxicity and immunogenicity have been reviewed elsewhere [199]. Here we focus on use of CPPs for delivery of proteins to CNS. Schwarze and colleagues published a seminal work demonstrating potential of CPP to deliver proteins across BBB [200]. In their study the NH2-terminal TAT (477)-galactosidase fusion protein (120 kDa) injected i.p. in mice was detected by immunochemical staining initially at 2 hr in brain microvessels then at 4 hr in brain parenchyma. No PK studies were performed. Nevertheless galactosidase activity was visualized in sagittal and coronal brain sections at the same time as in liver, kidney, lung and heart (myocardium) and spleen. TAT didn’t appear to disrupt BBB as the Evan’s blue albumin complexes co-injected with TAT have been excluded from the brain tissues. Subsequently, TAT peptide was fused with GDNF and injected i.p. inside a mouse model of PD. The fusion protein crossed the BBB and reached substantia nigra as was shown by immunohistochemical staining. Nevertheless, the remedy did not stop the loss of dopaminergic neurons in PD mice, possibly because the volume of the fusion protein delivered for the target website was not sufficient [201]. A TAT-based program was also utilized to deliver Bcl-xL protein, a well-characterized death-suppression molecule, towards the CNS for therapy of stroke. Intraperitoneal injection of TAT and Bcl-xL fusion protein resulted within a robust protein transduction in neurons, and a dose-dependent decrease of cerebral infarction inside a mouse middle cerebral artery occlusion (MCAO) model of ischemic stroke [202]. Similarly, a decreased infarct volume and neurological deficits have been observed after i.v. injection of TAT-Bcl-xL fusion protein 1 hr. ahead of or right away immediately after the ischemia induced in a rat MCAO model [203]. A recent study reported that TAT-leptin fusion protein was i.v. injected to mice fed with high-fat diet regime. Immunohistochemical stainingNIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author ManuscriptJ Handle Release. Author manuscript; readily available in PMC 2015 September 28.Yi et al.Pagesuggested improve in leptin accumulation in hypothalamus in the TAT-leptin treated mice, in CD54/ICAM-1 Proteins Molecular Weight comparison to the unmodified leptin or saline-treated animals. Importantly, TAT-leptin also prevented body-weight acquire much more efficiently when compared with leptin [204]. Cai et al. recently described optimistic effects of TAT-mediated delivery of neuroglobin (Ngb) on focal cerebral ischemia outcome in mice [205]. After i.v. injection the TAT-Ngb fusion protein was detected in mice brain GnRH Proteins custom synthesis tissues by immunohistochemistry and western blotting. The group treated with TAT-Ngb two hr. before MCAO showed smaller brain infarct volume and improved neurologic outcomes compared to the manage groups. Moreover, the group treated with TAT-Ngb immediately after MCAO and reperfusion showed considerably elevated neuronal survival in the striatum, in comparison with the controls [205]. In addition to TAT some other CPPs, like Syn-B vectors and Rabies virus glycoproteinderived peptide (RDP), had been also shown to provide little molecules and proteins across BBB [206, 207]. For instance, Xiang et al reported efficient hippocampus targeting by a galactosidase-RDP fusion protein [206]. Interestingly, a uncomplicated mixing of a protein with CPP also improved delivery of many proteins such as -galactosidase, human IgG and IgM to mouse brain [208]. Nevertheless, CPP have displayed many toxicities includin.