Guerra, E. C. | Search bioRxiv

bioRxiv2021

ACE2 expression in rat brain: implications for COVID-19 associated neurological manifestations

We examined cell type-specific expression and distribution of rat brain angiotensin converting enzyme 2 (ACE2), the receptor for SARS-CoV-2, in rodent brain. ACE2 is ubiquitously present in brain vasculature, with the highest density of ACE2 expressing capillaries found in the olfactory bulb, the hypothalamic paraventricular, supraoptic and mammillary nuclei, the midbrain substantia nigra and ventral tegmental area, and the hindbrain pontine nucleus, pre-Botzinger complex, and nucleus of tractus solitarius. ACE2 was expressed in astrocytes and astrocytic foot processes, pericytes and endothelial cells, key components of the blood-brain-barrier. We found discrete neuronal groups immunopositive for ACE2 in brainstem respiratory rhythm generating centers including the pontine nucleus, the parafascicular/retrotrapezoid nucleus, the parabrachial nucleus, the Botzinger and pre-Botzinger complex and the nucleus of tractus solitarius; in arousal-related pontine reticular nucleus and in gigantocellular reticular nuclei; in brainstem aminergic nuclei, including substantia nigra, ventral tegmental area, dorsal raphe, and locus coeruleus; in the epithalamic habenula, hypothalamic paraventricular and suprammamillary nuclei; and in the hippocampus. Identification of ACE2-expressing neurons in rat brain within well-established functional circuits facilitates prediction of possible neurological manifestations of brain ACE2 dysregulation during and after COVID-19 infection. HighlightsO_LIACE2 is present in astrocytes, pericytes, and endothelia of the blood brain barrier. C_LIO_LINeuronal ACE2 expression is shown in discrete nuclei through the brain. C_LIO_LIBrainstem breathing, arousal-related, hypothalamic and limbic nuclei express ACE2. C_LIO_LIACE2 is expressed in circuits potentially involved in COVID-19 pathophysiology. C_LI

neuroscience↗

bioRxiv2020

The gut microbiome stability of a butterflyfish is disrupted on severely degraded Caribbean coral reefs

Environmental degradation has the potential to alter key mutualisms that underline the structure and function of ecological communities. While it is well recognized that the global loss of coral reefs alters fish communities, the effects of habitat degradation on microbial communities associated with fishes remain largely unknown despite their fundamental roles in host nutrition and immunity. Using a gradient of reef degradation, we show that the gut microbiome of a facultative, coral-feeding butterflyfish (Chaetodon capistratus) is significantly more variable among individuals at degraded reefs with very low live coral cover (~0%) than reefs with higher coral cover (~30%), mirroring a known pattern of microbial imbalance observed in immunodeficient humans and other stressed or diseased animals. We demonstrate that fish gut microbiomes on severely degraded reefs have a lower abundance of Endozoicomonas and a higher diversity of anaerobic fermentative bacteria, which suggests a broader and less coral dominated diet. The observed shifts in fish gut bacterial communities across the habitat gradient extend to a small set of potentially beneficial host associated bacteria (i.e., the core microbiome) suggesting essential fish-microbiome interactions are vulnerable to severe coral degradation.

ecology↗