RESUMO
Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has been especially devastating to patients with comorbidities, including metabolic and cardiovascular diseases. Elevated blood glucose during SARS-CoV-2 infection increased mortality of COVID-19 patients, although the mechanisms are not well understood. It has been previously demonstrated that glucose transport and utilization is a crucial pathway for other highly infectious RNA viruses. Thus, we hypothesized that SARS-CoV-2 infection could lead to alterations in cellular and whole-body glucose metabolism. Specific pathogen free domestic cats were intratracheally inoculated with USA-WA1/2020 (Wild-type) SARS-CoV-2 or vehicle-inoculated, then sacrificed at 4- and 8-days post-inoculation (dpi). Blood glucose and cortisol concentrations were elevated at 4 and 8 dpi. Blood ketones, insulin, and angiotensin 2 concentrations remained unchanged throughout the experimental timeline. SARS-CoV-2 RNA was detected in the lung and heart, without changes in angiotensin converting enzyme 2 (ACE2) RNA expression. In the lung, SARS-CoV-2 infection increased glucose transporter 1 (GLUT1) protein level at 4 and 8 dpi., while GLUT4 level was only upregulated at 8 dpi. In the heart, GLUT-1 and -4 protein levels remained unchanged. Furthermore, GLUT1 level was upregulated in the skeletal muscle at 8 dpi, and AMPK was activated in the heart of infected cats. SARS-CoV-2 infection increased blood glucose concentration and pulmonary GLUT protein levels. These findings suggest that SARS-CoV-2 infection induces metabolic reprogramming primarily in the lung to support viral replication. Furthermore, this translational feline model mimicked human COVID-19 and could be used to explore novel therapeutic targets to treat metabolic disease during SARS-CoV-2 infection.
RESUMO
Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) causes enhanced mortality in people with metabolic and cardiovascular diseases. Other highly infectious RNA viruses have demonstrated dependence on glucose transport and utilization, so we hypothesized that SARS-CoV-2 infection could lead to alterations in cellular and whole-body glucose metabolism. Twenty-four healthy domestic cats were intratracheally inoculated with B.1.617.2 (delta) SARS-CoV-2 and samples were collected at 4- and 12-days post-inoculation (dpi). Blood glucose and circulating cortisol concentrations were elevated at 4 and 12 dpi. Serum insulin concentration was statistically significantly decreased, while angiotensin 2 concentration was elevated at 12 dpi. SARS-CoV-2 RNA was detected in the pancreas and skeletal muscle at low levels; however, no change in the number of insulin-producing cells or proinflammatory cytokines was observed in the pancreas of infected cats through 12 dpi. SARS-CoV-2 infection statistically significantly increased GLUT protein expression in both the heart and lungs, correlating with increased AMPK expression. In brief, SARS-CoV-2 increased blood glucose concentration and cardio-pulmonary GLUT expression through an AMPK-dependent mechanism, without affecting the pancreas, suggesting that SARS-CoV-2 induces the reprogramming of host glucose metabolism. A better understanding of host cell metabolism and virus crosstalk could lead to the discovery of novel metabolic therapeutic targets for patients affected by COVID-19.
