How A Change in Immune Cell Metabolism Contributes to Severe COVID-19

Illustration of energy metablism in cell.

There is still a lot we don’t know about COVID-19 and the virus, SARS-CoV-2, that caused the pandemic and changed the way we live. But there are two things we do know about the disease: 1) Patients with diabetes and high blood glucose levels are more likely to develop severe COVID-19 symptoms with higher mortality.  2) Patients that experience an uncontrolled inflammatory response, called the cytokine storm, also develop more severe COVID-19 symptoms. The fact that both high glucose levels and an exaggerated immune response drive severe disease suggests that the two may be linked. But how? The answer may lie in the metabolism of immune cells in the lungs of COVID-19 patients, according to a recent study published in Cell Metabolism.

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Predictive In Vitro Cytotoxicity Testing

Cell culture cytotoxicity testing is used as a predictor for animal toxicity. High-throughput cytotoxicity screening using ATP levels as an indicator of cell viability is the current gold standard for such predictive cytotoxicity testing. Multiplexing assay chemistries allows researchers to measure multiple parameters on a single sample in order to get a more complete picture of what is happening when cells are exposed to a treatment compound. For example multiplex assays using three protease activities as markers of viable, necrotic and apoptotic cells give researchers a tool for uncovering the mechanism of cell death when toxicity is observed and control for assay artifacts. In their book chapter, “Cytotoxicity Testing: Measuring Viable Cells, Dead Cells and Detecting Mechanism of Cell Death”, Riss, Moravec and Niles, describe protocols for in vitro toxicity testing using ATP-based assays and multiplex assays. The chapter provides protocols, an extensive materials required list, example data, and a thorough notes section describing appropriate controls, issues of assay timing, and other considerations that affect assay success. You can find it in Methods in Molecular Biology Vol. 740, Mammalian Cell Viability Methods and Protocols (Humana Press).

Sirtuins and Marathon Running: No Pain No Gain?

This post was chosen as an Editor's Selection for ResearchBlogging.orgOn Saturday I ran 12 miles. “Well, at least I have staved off apoptosis in my peripheral blood mononuclear cells” I thought as I hobbled down the stairs on Sunday morning. Normally I don’t think about mononuclear cells on Sunday mornings, only of coffee. However, a paper published last week in BMC Physiology changed that for me, at least temporarily.

Ankle band at the Courir Pour Elles run/walk recently.

The paper, by Marfe et al, investigated whether the physiological stress associated with strenuous exercise may cause apoptosis and contribute to loss of lymphocytes. This paper investigated whether apoptosis is increased in cells of the immune system after running a marathon. The authors studied the expression of various stress-related proteins in peripheral blood lymphocytes in 10 male amateur runners, examining the expression of various antioxidants, stress proteins and apoptotic markers before and after (2-hours post-race) running a marathon. They found that expression of the apoptotic marker bax was decreased significantly after the marathon, while levels of antiapoptotic bcl-2 RNA increased. The amount of propcaspase 9 did not change pre and post race, indicating that there was no change in levels of apoptosis before and after the race.

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