Neuroglobin and cytoglobin expression in the human brain

Neuroglobin and cytoglobin are new members of the heme-globin family. Both globins are primarily expressed in neurons of the brain and retina. Neuroglobin and cytoglobin have been suggested as novel therapeutic targets in various neurodegenerative diseases based on their oxygen binding and cell protecting properties. However, findings in Neuroglobin-deficient mice question the endogenous neuroprotective properties. The expression pattern of neuroglobin and cytoglobin in the rodent brain is also in contradiction to a major role of neuronal protection. In a recent study, neuroglobin was ubiquitously expressed and up-regulated following stroke in the human brain. The present study aimed at confirming our previous observations in rodents using two post-mortem human brains. The anatomical localization of neuroglobin and cytoglobin in the human brain is much like what has been described for the rodent brain. Neuroglobin is highly expressed in the hypothalamus, amygdale and in the pontine tegmental nuclei, but not in the hippocampus. Cytoglobin is highly expressed in the habenula, hypothalamus, thalamus, hippocampus and the pontine tegmental nuclei. We only detected a low expression of neuroglobin and cytoglobin in the cerebral cortex, while no expression in the cerebellar cortex was detectable. We provide a neuroanatomical indication for a different role of neuroglobin and cytoglobin in the human brain.