George, John Phillip

Abstract The Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection continues to expand its horizon through the development of diverse symptoms, particularly concerning long COVID. The patients infected with the SARS-CoV-2 are being reported to develop new symptoms such as brain fog, fatigue, and other symptoms that are not limited to the respiratory system. The SARS-CoV-2 utilizes the human ion channels (HICs) and molecules involved in lipid metabolism from their entry to their egress. Here, to identify molecular alterations in HICs and lipid metabolism-related genes, transcriptomic data of 277 SARS-CoV-2 infected patients were analyzed. 287 HICs and 754 lipid metabolism-related genes were found to be differentially expressed in SARS-CoV-2 infected patients. Further, an interactome of altered HICs and lipid metabolism-related proteins with SARS-CoV-2 proteins was generated. Extensive data mining approach was employed to generate a pathway map highlighting alteration in several pathways including calcium signaling, long-term depression, and cholesterol metabolism in SARS-CoV-2 infected patients. Moreover, 17 potential drugs with known modes of action that interact with 4 altered HICs including inositol 1,4,5-triphosphate (InsP3) receptors and gap junction protein alpha 1 were identified. Most likely, these HICs are potential candidates for drug repurposing in patients infected with SARS-CoV-2 and require further experimental validation.

Abstract Background Sphingolipids play a crucial role in cellular functions and are essential components of cell membranes, signaling molecules, and lipid metabolism. In particular, ceramide is a key intermediate in sphingolipid metabolism and defects in ceramide metabolism can lead to various inborn errors of metabolism, making ceramides important targets for clinical screening and diagnosis. Detecting altered concentration patterns of sphingolipids is desirable for distinguishing related inborn errors of metabolism for diagnosis and treatment monitoring. Methods We developed a liquid chromatography-tandem mass spectrometry method with a pathway-oriented approach to focus on sphingolipids involved in ceramide metabolism. A total of 47 sphingolipids bearing different head groups and side chains were targeted. Precision/reproducibility, linearity, and spike recovery extraction efficiency tests were performed on plasma and serum samples from confirmed cases of sphingolipidosis. Results Linearity of the method showed the coefficient of determination (r2) for all standards to be >0.99 with a slope of 1.00 ± 0.01. Intra- and interday reproducibility of standards spiked into plasma and serum revealed a coefficient of variation <20%. Spike and recovery assessment showed recovery values of 80%–120% for all standards. Altered levels of sphingolipids from patients with hereditary sensory and autonomic neuropathy caused by pathogenic variants in SPTLC2 and hypomyelinating leukodystrophy related to variants in DEGS1 were detected, in agreement with trends reported in earlier studies confirming the utility of this pathway-centric method. Conclusions This method can serve as a useful tool to simultaneously monitor sphingolipids, enabling screening and diagnosis of inborn errors of ceramide metabolism.