D description on the CPP internalization mechanisms, as well as other properties which include stability, toxicity and immunogenicity were reviewed elsewhere [199]. Right here we concentrate on use of CPPs for delivery of proteins to CNS. Schwarze and colleagues published a seminal function demonstrating potential of CPP to provide proteins across BBB [200]. In their study the NH2-terminal TAT (477)-galactosidase fusion CD185 Proteins Recombinant Proteins protein (120 kDa) injected i.p. in mice was detected by immunochemical staining initially at two hr in brain microvessels and then at four hr in brain parenchyma. No PK research have been performed. Nevertheless galactosidase activity was visualized in sagittal and coronal brain sections as well as in liver, kidney, lung and heart (myocardium) and spleen. TAT did not seem to disrupt BBB as the Evan’s blue albumin complexes co-injected with TAT had 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. On the other hand, the remedy did not avoid the loss of dopaminergic neurons in PD mice, possibly since the volume of the fusion protein delivered for the target website was not adequate [201]. A TAT-based technique was also utilized to provide 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 in a mouse middle cerebral artery occlusion (MCAO) model of ischemic stroke [202]. Similarly, a reduced infarct volume and neurological deficits have been observed immediately after i.v. injection of TAT-Bcl-xL fusion protein 1 hr. ahead of or quickly immediately after the ischemia induced within 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. Immunohistochemical stainingNIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author ManuscriptJ Control Release. Author manuscript; available in PMC 2015 September 28.Yi et al.Pagesuggested boost in leptin accumulation in hypothalamus inside the TAT-leptin CD3d Proteins custom synthesis treated mice, in comparison with the unmodified leptin or saline-treated animals. Importantly, TAT-leptin also prevented body-weight acquire extra efficiently in comparison to leptin [204]. Cai et al. not too long ago described positive effects of TAT-mediated delivery of neuroglobin (Ngb) on focal cerebral ischemia outcome in mice [205]. Right after i.v. injection the TAT-Ngb fusion protein was detected in mice brain tissues by immunohistochemistry and western blotting. The group treated with TAT-Ngb two hr. ahead of MCAO showed smaller brain infarct volume and enhanced neurologic outcomes in comparison with the control groups. In addition, the group treated with TAT-Ngb soon after MCAO and reperfusion showed significantly enhanced neuronal survival in the striatum, when compared with the controls [205]. Apart from TAT some other CPPs, including Syn-B vectors and Rabies virus glycoproteinderived peptide (RDP), have been also shown to deliver small molecules and proteins across BBB [206, 207]. As an example, 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 for example -galactosidase, human IgG and IgM to mouse brain [208]. Nonetheless, CPP have displayed several toxicities includin.