INVESTIGATOR(S): Shenandoah Robinson, M.D.
SUMMARY: Our overarching goal is to prevent debilitating COVID-19 sequelae using neuro-immunomodulatory therapies. Specifically, we propose to test a cocktail of neurorestorative medications. SARS-CoV-2 infection causes brain injury by two mechanisms: 1) direct invasion of brain cells via the ACE2 receptors, and 2) secondary injury mediated by the peripheral inflammatory response, the focus of this proposal. We hypothesis that those who suffer a severe illness with SARS-CoV-2 infection, especially those with pre-existing conditions, have a baseline hyper-reactive immune system that propagates neuroinflammation following peripheral cytokine surges.
We predict combination pharmacotherapy that capitalizes on endogenous neurorestoration will safely mitigate chronic neurological sequelae from COVID-19. We propose to use a combination of melatonin (MLT) and propyl hydroxylase domain inhibitors (PHDI) to modulate neuroinflammation and prevent neurological deficits after serious illness from COVID-19. We have shown in multiple preclinical models of brain insults that monotherapy with either EPO or MLT is only mildly effective compared to combinatorial therapy. We propose treatment with a sustained, safe course of PHDI+MLT during COVID-like illness to prevent neurological deficits from chronic neuro-inflammation.
To mimic inflammation from pre-existing conditions, we prime the immune system in rats with systemic injection of bacterial lipopolysaccharide. Currently, we are using subsequent poly(I:C) injection to replicate viral infection with COVID-19. When CRISPR-Cas9 rats with humanized ACE2 receptors become available, we will transition to using them as our model system, with SARS-CoV-2 spike protein to instigate systemic illness. To date, to mimic differences in response to SARS-CoV-2 infection across the lifespan, we have developed four models: perinatal, juvenile, middle-age and older adult.
We propose two Aims: Aim 1: Investigate differences in serum and brain inflammatory pathways across four ages in response to PHDI+MLT treatment after poly(I:C) illness induction. We will use a combination of peripheral blood monocyte cell stimulation assays, multiplex electrochemiluminescent assays, flow cytometry and single-cell RNAseq to quantify inflammatory signatures. We predict immune responses will vary by age, and that all ages will show attenuation of peripheral and brain damaging neuroinflammation with PHDI+MLT treatment. Aim 2: Investigate whether PHDI+MLT treatment prevents chronic cognitive deficits and pain. We will use highly translational touchscreen platforms, similar to those used to test cognition in humans, to measure executive function and attention. We will also define chronic pain phenotypes by assaying for mechanical allodynia, thermal hypersensitivity and late phase formalin response. These results will be correlated with advanced tractography using diffusion tensor imaging and functional brain MRI. We predict robust correlation between neurorestoration of cognition and pain, and imaging outcomes. While many questions will remain from these initial studies, we expect to have data to justify early translation to clinical trials.