Frameless Stereotactic Targeting of the Cerebellar Dentate Nucleus in Nonhuman Primates: Translatable Model for the Surgical Delivery of Gene Therapy

Gene transfer experiments in nonhuman primates have been shown to be predictive of success in human clinical gene therapy trials. In most nonhuman primate studies, hematopoietic stem cells (HSCs) collected from the peripheral blood or bone marrow after administration of granulocyte colony-stimulating factor (G-CSF) + stem cell factor (SCF) have been used as targets, but this cytokine combination is not generally available for clinical use, and the optimum target cell population has not been systematically studied. In our current study we tested the retroviral transduction efficiency of rhesus macaque peripheral blood CD34+ cells collected after administration of different cytokine mobilization regimens, directly comparing G-CSF+SCF versus G-CSF alone or G-CSF+Flt3-L in competitive repopulation assays. Vector supernatant was added daily for 96 hours in the presence of stimulatory cytokines. The transduction efficiency of HSCs as assessed by in vitro colony-forming assays was equivalent in all 5 animals tested, but the in vivo levels of mononuclear cell and granulocyte marking was higher at all time points derived from target CD34+ cells collected after G-CSF+SCF mobilization compared with target cells collected after G-CSF (n = 3) or G-CSF+Flt3-L (n = 2) mobilization. In 3 of the animals long-term marking levels of 5% to 25% were achieved, but originating only from the G-CSF+SCF–mobilized target cells. Transduction efficiency of HSCs collected by different mobilization regimens can vary significantly and is superior with G-CSF+SCF administration. The difference in transduction efficiency of HSCs collected from different sources should be considered whenever planning clinical gene therapy trials and should preferably be tested directly in comparative studies.

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Spinal Projections of the Cat Parvicellular Red Nucleus

Journal of Neurophysiology ◽

10.1152/jn.00950.2000 ◽

2002 ◽

Vol 87 (1) ◽

pp. 453-468 ◽

Cited By ~ 24

Author(s):

Milton Pong ◽

Kris M. Horn ◽

Alan R. Gibson

Keyword(s):

Spinal Cord ◽

Dentate Nucleus ◽

Inferior Olive ◽

Red Nucleus ◽

Interpositus Nucleus ◽

Limb Musculature ◽

Caudal Portion ◽

Cerebellar Interpositus Nucleus ◽

Cerebellar Dentate Nucleus ◽

Rostral Portion

Traditionally, the red nucleus of the cat is divided into two parts: a large-celled, magnocellular, division (RNm) and a small-celled, parvicellular, division (RNp). The RNm projects to the spinal cord and receives input from the cerebellar interpositus nucleus. The RNp projects to the inferior olive and receives input from the cerebellar dentate nucleus. In this report, we reexamine the connections of the red nucleus using the bidirectional tracer wheat germ agglutinin-horseradish peroxidase (WGA-HRP). Our findings demonstrate that the cat RNp has a large caudal and lateral region that projects to contralateral spinal cord and not to the inferior olive. The spinally projecting region of RNp receives input from the dentate nucleus and a lateral segment of anterior interpositus. Cervical projections from the red nucleus show a topography with the rostral portion of RNp favoring upper segments and the caudal portion of RNm favoring lower segments. The results show that dentate output can influence spinal activity without passing through the cerebral cortex. For the control of movements such as reaching and grasping, we suggest that RNp and dentate focus on the control of proximal limb musculature, whereas RNm and the anterior interpositus focus on the control of distal limb musculature. We also suggest that other species are likely to have a small-celled area of red nucleus projecting to the spinal cord.

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