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Emerging evidence indicates that activation of complement system leading to the formation of the membrane attack complex (MAC) plays a detrimental role in COVID-19. However, their pathogenic roles have never been experimentally investigated before. We used three knock out mice strains (1. C3−/−; 2. C7−/−; and 3. Cd59ab−/−) to evaluate the role of complement in severe COVID-19 pathogenesis. C3 deficient mice lack a key common component of all three complement activation pathways and are unable to generate C3 and C5 convertases. C7 deficient mice lack a complement protein needed for MAC formation. Cd59ab deficient mice lack an important inhibitor of MAC formation. We also used anti-C5 antibody to block and evaluate the therapeutic potential of inhibiting MAC formation. We demonstrate that inhibition of complement activation (in C3−/−) and MAC formation (in C3−/−. C7−/−, and anti-C5 antibody) attenuates severe COVID-19; whereas enhancement of MAC formation (Cd59ab−/−) accelerates severe COVID-19. The degree of MAC but not C3 deposits in the lungs of C3−/−, C7−/− mice, and Cd59ab−/− mice as compared to their control mice is associated with the attenuation or acceleration of SARS-CoV-2-induced disease. Further, the lack of terminal complement activation for the formation of MAC in C7 deficient mice protects endothelial dysfunction, which is associated with the attenuation of diseases and pathologic changes. Our results demonstrated the causative effect of MAC in severe COVID-19 and indicate a potential avenue for modulating the complement system and MAC formation in the treatment of severe COVID-19. [ABSTRACT FROM AUTHOR]

Heme-regulated inhibitor (HRI), an eukaryotic translation initiation factor 2 alpha (eIF2α) kinase, plays critical roles in cell proliferation, differentiation, adaptation to stress, and hemoglobin disorders. HRI phosphorylates eIF2α, which couples cellular signals, including endoplasmic reticulum (ER) stress, to translation. We previously identified 1,3-diarylureas and 1-((1,4-trans)-4-aryloxycyclohexyl)-3-arylureas (cHAUs) as specific activators of HRI that trigger the eIF2α phosphorylation arm of ER stress response as molecular probes for studying HRI biology and its potential as a druggable target. To develop drug-like cHAUs needed for in vivo studies, we undertook bioassay-guided structure-activity relationship studies and tested them in the surrogate eIF2α phosphorylation and cell proliferation assays. We further evaluated some of these cHAUs in endogenous eIF2α phosphorylation and in the expression of the transcription factor C/EBP homologous protein (CHOP) and its mRNA, demonstrating significantly improved solubility and/or potencies. These cHAUs are excellent candidates for lead optimization for development of investigational new drugs that potently and specifically activate HRI.

Most sporadic breast and ovarian cancers express low levels of the breast cancer susceptibility gene, BRCA1. The BRCA1 gene produces two transcripts, mRNAa and mRNAb. mRNAb, present in breast cancer but not in normal mammary epithelial cells, contains three upstream open reading frames (uORFs) in its 5′UTR and is translationally repressed. Comparable tandem uORFs are characteristically seen in mRNAs whose translational efficiency paradoxically increases when the overall translation rate is decreased due to phosphorylation of eukaryotic translation initiation factor 2 α (eIF2α). Here we show fish oil derived eicosopanthenoic acid (EPA) that induces eIF2α phosphorylation translationally up-regulates the expression of BRCA1 in human breast cancer cells. We demonstrate further that a diet rich in EPA strongly induces expression of BRCA1 in human breast cancer xenografts.

pGCD59 is an emerging biomarker for diabetes and GDM. In 1,000 women undergoing 2-step GDM screening, pGCD59 at weeks 24-28 classified GDM subjects with high sensitivity and specificity and was associated with the risk of large for gestational age (LGA) babies. GDM early in pregnancy is a public health challenge because it increases the risk of adverse outcomes. To assess pGCD59 as a predictor of early GDM and abnormal outcomes, levels of pGCD59 were measured in 807 samples from women undergoing a 1-step OGTT (75gr-2hr; WHO 2013 criteria) at <20 weeks gestation in the DALI study, a European trial of women at high risk of GDM. Results: Among 807 samples, 481 subjects had normal glucose tolerance throughout the pregnancy (Controls) and 205 met WHO 2013 criteria for GDM at <20 weeks (Cases). Age, race/ethnicity, and BMI were similar among Cases and Controls. pGCD59 accurately predicted the diagnosis of GDM in early pregnancy (AUCROC = 0.9). The risk of LGA (>90thpercentile) was positively associated with pGCD59 (p = 0.04) in Cases but not in Controls. Cases who delivered LGA newborns had higher median levels of pGCD59 than those who delivered non-LGA newborns (pGCD59 (SPU): Case-LGA: 4.4[1.5], Case-non-LGA 3.8[1.2]; p = 0.03). In contrast, median levels of pGCD59 were similar in Controls who delivered LGA or non-LGA newborns. The risk of congenital malformations or neonatal hypoglycemia was also associated with higher maternal levels of pGCD59: i) mothers who delivered babies with malformations had 60% higher mean pGCD59, ii) the odds ratio of a malformation was 3.4 (95% CI: 1.1, 10.1) in the 4th as compared with the 1st quartile of pGCD59, and iii) one unit increase in pGCD59 was associated with a 70% higher odds ratio of neonatal hypoglycemia. HbA1c failed to predict GDM or abnormal neonatal outcomes. Conclusion: Our results indicate that pGCD59 is a simple and accurate biomarker for early detection of GDM and for risk assessment of its potentially serious complications. Disclosure: J. Halperin: Stock/Shareholder; Self; Mellitus, LLC. D. Ma: None. M.A. Luque-Fernandez: None. D. Bogdanet: None. G. Desoye: None. F.P. Dunne: None. Funding: National Institutes of Health (R01DK101442 to J.H.); European Union (242187) [ABSTRACT FROM AUTHOR]

Most sporadic breast and ovarian cancers express low levels of the breast cancer susceptibility gene, BRCA1. The BRCA1 gene produces two transcripts, mRNAa and mRNAb. mRNAb, present in breast cancer but not in normal mammary epithelial cells, contains three upstream open reading frames (uORFs) in its 5'UTR and is translationally repressed. Comparable tandem uORFs are characteristically seen in mRNAs whose translational efficiency paradoxically increases when the overall translation rate is decreased due to phosphorylation of eukaryotic translation initiation factor 2 α (eIF2α). Here we show fish oil derived eicosopanthenoic acid (EPA) that induces eIF2α phosphorylation translationally up-regulates the expression of BRCA1 in human breast cancer cells. We demonstrate further that a diet rich in EPA strongly induces expression of BRCA1 in human breast cancer xenografts.