LOCALIZATION PROFILE OF CATHEPSIN L IN THE BRAIN OF AFRICAN GIANT RAT (Cricestomys gambianus)

Claudius Luziga
1, Bui Thi To Nga2, Isaac Kashoma3, Abdul Katakweba4, Yamamoto Yoshimi5,

  1. Department of veterinary Anatomy, Sokoine University of Agriculture, Tanzania
  2. Department of Veterinary Pathology, Vietnam National University of Agriculture, Vietnam
  3. Department of Surgery and Theriogenology, Sokoine University of Agriculture, Tanzania
  4. Pest Management Centre (PMC), Sokoine University of Agriculture, Tanzania
  5. Laboratory of Biochemistry and Radiation Biology, Department of Veterinary Sciences, Yamaguchi University, Yamaguchi 753- 8515, Japan

Correspondence to: Claudius Luziga, Tel. +255 765 774033; P.O. Box 3016 Morogoro, Tanzania. E-mail address: luziga@suanet.ac.tz

ABSTRACT
Cathepsins, are members of the papain superfamily of mammalian lysosomal cysteine proteases. Among others there are two prominent members with broad substrate specificity, these are cathepsin B and cathepsin L that are known to be involved in the process of intra- and extra-cellular protein degradation and turnover. However, the in vivo targets of cathepsin L in nervous tissues are yet to be identified. We examined by immunofluorescence studies the distribution pattern of cathepsin L protein and determine the specific cell types synthesizing the enzyme in the brain of African giant rats (Cricetomys gambianus). Results showed that Cathepsin L protein was localized in various brain regions of the giant rats. In the telencephalon, immunoreactivity was identified in cerebral cortex and subcortical structures, hippocampus, amygdala and basal ganglia. Within the diencephalon high density of positive signals was observed in mediodorsal and lateral posterior thalamic nuclei and medial habenular nucleus. In the mesencephalon, cathepsin L was detected in the substantia nigra and cerebral peduncles. Strong labeling in the hypothalamus was present in the anterior commissure and median eminence while in the cerebellum cathepsin L was observed in the deep white matter, granule cell layer, stellate, and basket cells of cerebellar cortex and in the Purkinje neurons. The distribution pattern and functional implications of cathespin L in relation to spatial memory establishment, learning coordination and disease mechanisms is discussed.

Keywords: Cathepsin L, immunofluorescence, Cricestomys, brain

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