Long-term neuroinflammation induced by influenza A virus infection and the impact on hippocampal neuron morphology and function

ABSTRACT: Acute influenza infection can be associated with neurological symptoms. Especially after the major pandemics reports about neuropsychiatric complications accumulated. However, the long-term consequences for the CNS of an infection with neurotropic but also non-neurotropic influenza A virus (IAV) variants remain largely elusive. The results presented here show that synapse loss in the hippocampus upon an infection with neurotropic H7N7 (rSC35M) as well as non-neurotropic H3N2 (maHK68) persists well beyond the acute phase of the disease. While hippocampal synapse number was significantly reduced 30 days post infection with both H7N7 and H3N2, full recovery could be observed 120 days post infection. Notably, infection with H1N1 (PR8) which was shown previously to affect spine number and hippocampus-dependent learning during the acute phase had no significant long-term effects. Spine loss was associated with an increase in the number of activated microglia, reduced long-term potentiation and an impairment in spatial memory formation in the water maze indicating long-term inflammation induced functional and structural alterations in the hippocampus. Our data, therefore, provide evidence that while neuroinflammation induced by neurotropic H7N7 showed the strongest effect, also the systemic infection with a non-neurotropic influenza virus can result in long-term impairments in synapse number and function in the hippocampus. While young animals fully recover the outcome might be different in aged or otherwise compromised individuals, thereby directing future treatment strategies to pay attention to IAV induced processes of neuroinflammation.

ORGANISM(S): Mus musculus

PROVIDER: GSE106620 | GEO | 2018/12/31

REPOSITORIES: GEO