Niewold, Timothy B.

Abstract Background Viral infection outcomes vary widely between individuals, ranging from mild symptoms to severe organ failure and death, and it is clear that host genetic factors play a role in this variability. Type I interferon (IFN) is a critical anti-viral cytokine, and we have previously noted differences in type I IFN levels between world populations. Methods In this study, we investigate the interrelationship between regional European genetic ancestry, type I IFN levels and severe viral infection outcomes. Results In cohorts of European ancestry lupus patients living in Europe, we noted higher IFN in the Northwestern populations as compared to Southeastern populations. In an independent cohort of European ancestry lupus patients from the USA with varying proportional regional European genetic admixture, we observed the same Northwest vs. Southeast European ancestry IFN gradient. We developed a model to predict type I IFN level based on regional European ancestry (Area under the curve (AUC) = 0.73, P = 6.1e-6). Examining large databases containing serious viral outcomes data, we found that lower predicted IFN in the corresponding European country was significantly correlated with increased viral infection fatality rate, including Coronavirus Disease 2019 (COVID-19), viral hepatitis and HIV [correlation coefficients: −0.79 (P = 4e-2), −0.94 (P = 6e-3) and −0.96 (P = 8e-2), respectively]. Conclusions This association between predicted type I IFN level and viral outcome severity suggests a potential causal relationship, as greater intrinsic type I IFN is beneficial in host defense against viruses. Genetic testing could provide insight into individual and population level risk of fatality due to viruses prior to infection, across a wide range of viral pathogens.

Abstract Background/Purpose Interferon (IFN) gene expression signatures have been observed in whole blood and mixed immune cell populations in systemic lupus erythematosus (SLE), but the significance of this IFN signaling in immune cell subsets is not well understood. We examined gene expression in individual SLE patient monocytes to explore the impact of increased IFN-induced transcription in single cells. Methods CD14++CD16- classical monocytes and CD14dimCD16+ non classical monocytes from SLE patients were purified by magnetic separation. Single cells were isolated, and gene expression in each individual cell was examined by rtPCR. Results Monocytes from the same SLE patient blood sample demonstrated varying levels of IFN-induced gene expression. In classical monocytes, high IFN score correlated with CD32a, IL1B, and IL8 expression. In non-classical monocytes, high IFN score was correlated with a larger number of inflammatory mediators, including cytokines such as IL12, IL23, and IL15; the immune receptors CD36, CD32a, CD80, and TLR7; and inflammatory signaling genes such as RELA, STAT2, IRAK1, IRAK4, and MyD88. ConclusionWe observed striking diversity in the IFN responses of individual monocytes, demonstrating that IFN signaling has distinct effects upon classical and non-classical monocytes. Single cell studies can reveal effects of IFN on single immune cells and uncommon populations such as non-classical monocytes, which would be masked in whole blood or mixed cell populations.

Abstract Processes that lead to clinical illness in SLE years before diagnosis are not well characterized. This study evaluates the temporal relationship between autoantibody production, cytokine levels and the onset of SLE. Serial sera from 60 SLE cases before diagnosis with no ACR criteria to SLE classification (average timespan=4.4 years) and matched healthy controls (HC) were obtained from the DODSR. Sera samples were tested for autoantibodies (BioPlex2200), C-reactive protein (hs-CRP), Von Willebrand’s Factor (VWF) and 32 soluble inflammatory mediators, including cytokines, chemokines, and soluble receptors. Patient samples before ACR classification had significant (p < 0.01) alterations in 16 soluble mediators of inflammation, as well as VWF and hs-CRP. TNF Receptor levels, TNFRI, TNFRII, BLyS, and APRIL, dramatically increased as lupus classification approached (p < 0.001). The increase in TNFR shedding parallels the accumulation of autoantibodies in SLE cases. Interferon (IFN)-associated mediators of inflammation, IFN-γ, IP-10, MIG, and MIP-1α (p < 0.01), were also increased leading up to classification. That these alterations are present prior to the transition to active SLE suggests that multiple perturbations in immune-mediated inflammatory processes occur long before clinical classification and suggest that high-risk, pre-clinical individuals, can be identified before their illness is clinically manifested and damage occurs.

Significance Statement Renal artery stenosis (RAS) engenders stenotic-kidney ischemia, dysfunction, and injury, but whether these are mediated by cellular senescence has not been elucidated. INK-ATTAC transgenic mice, high-resolution imaging, and unbiased single-cell RNA sequencing of murine kidneys demonstrated cellular senescence as an important mechanism of progressive injury to epithelial/stromal cells within poststenotic kidneys. Both p16-specific and broad quercetin/dasatinib interventions to blunt senescence improved renal function and structure, underscoring the central role of senescence in the pathogenesis. Furthermore, this mechanism was conserved in human subjects with RAS. These observations reveal new mechanisms that contribute to the pathogenesis of chronic ischemic renal injury, and support the development of senolytic therapy to reduce senescent cell burden and delay renal injury. Background Peripheral vascular diseases may induce chronic ischemia and cellular injury distal to the arterial obstruction. Cellular senescence involves proliferation arrest in response to stress, which can damage neighboring cells. Renal artery stenosis (RAS) induces stenotic-kidney dysfunction and injury, but whether these arise from cellular senescenceand their temporal pattern remain unknown. Methods Chronic renal ischemia was induced in transgenic INK-ATTAC and wild type C57BL/6 mice by unilateral RAS, and kidney function ( in vivo micro-MRI) and tissue damage were assessed. Mouse healthy and stenotic kidneys were analyzed using unbiased single-cell RNA-sequencing. To demonstrate translational relevance, cellular senescence was studied in human stenotic kidneys. Results Using intraperitoneal AP20187 injections starting 1, 2, or 4 weeks after RAS, selective clearance of cells highly expressing p16 Ink4a attenuated cellular senescence and improved stenotic-kidney function; however, starting treatment immediately after RAS induction was unsuccessful. Broader clearance of senescent cells, using the oral senolytic combination dasatinib and quercetin, in C57BL/6 RAS mice was more effective in clearing cells positive for p21 ( Cdkn1a ) and alleviating renal dysfunction and damage. Unbiased, single-cell RNA sequencing in freshly dissociated cells from healthy and stenotic mouse kidneys identified stenotic-kidney epithelial cells undergoing both mesenchymal transition and senescence. As in mice, injured human stenotic kidneys exhibited cellular senescence, suggesting this process is conserved. Conclusions Maladaptive tubular cell senescence, involving upregulated p16 ( Cdkn2a ), p19 ( Cdkn2d ), and p21 ( Cdkn1a ) expression, is associated with renal dysfunction and injury in chronic ischemia. These findings support development of senolytic strategies to delay chronic ischemic renal injury.