Cyclosporine a directly affects human and mouse b cell migration in vitro by disrupting a hIF-1 αdependent, o2 sensing, molecular switch

Abstract

Background: Hypoxia is a potent molecular signal for cellular metabolism, mitochondrial function, and migration. Conditions of low oxygen tension trigger regulatory cascades mediated via the highly conserved HIF-1α post-translational modification system. In the adaptive immune response, B cells (Bc) are activated and differentiate under hypoxic conditions within lymph node germinal centers, and subsequently migrate to other compartments. During migration, they traverse through changing oxygen levels, ranging from 1-5% in the lymph node to 5-13% in the peripheral blood. Interestingly, the calcineurin inhibitor cyclosporine A is known to stimulate prolyl hydroxylase activity, resulting in HIF-1α destabilization and may alter Bc responses directly. Over 60% of patients taking calcineurin immunosuppressant medications have hypo-gammaglobulinemia and poor vaccine responses, putting them at high risk of infection with significantly increased morbidity and mortality. Results: We demonstrate that O 2 tension is a previously unrecognized Bc regulatory switch, altering CXCR4 and CXCR5 chemokine receptor signaling in activated Bc through HIF-1α expression, and controlling critical aspects of Bc migration. Our data demonstrate that calcineurin inhibition hinders this O 2 regulatory switch in primary human Bc. Conclusion: This previously unrecognized effect of calcineurin inhibition directly on human Bc has significant and direct clinical implications.

Executable Network Models of Integrated Multiomics Data

“…Crucially, the HIF1α signaling pathway is modulated only between 1% O 2 , CyA– and 1% O 2 , CyA+ samples, indicating that treatment with CyA is responsible for the differences in HIF1α-mediated phenotypic effects such as altered chemotaxis. Indeed, we have previously shown in our proteomic and phosphoproteomics data sets that HIF1α-regulated proteins and cytoskeletal pathways are modulated by O 2 levels. , This small list of pathways identified by is highly interpretable and specific to the condition under study, especially in comparison to currently available methods for multiomics pathway analysis, as shown in Section and Figure .…”

“…RAMOS B cells were cultured, treated, harvested, lysed, and digested as described previously . Samples were tagged with tandem mass tag (TMT) ten-plex reagents (0.2 mg) (Thermo Fisher Scientific, Waltham, MA) and fractionated as described.…”

“…Proteomics and phosphoproteomics data were collected and processed as described. , We retained only samples from the experimental conditions represented in all three data sets (Supplementary Table S1). In the case of the proteomics and phosphoproteomics data sets, we mapped protein names to gene names using Entrez and retained these gene names for downstream analysis, for consistency between data sets.…”

“…We also used the pipeline to infer Boolean regulatory rules and node modulation scores for a custom network constructed by composing the KEGG networks in (Supplementary Table S2). These signaling networks are known to be involved in the response of B cells to hypoxia or are linked to chemotaxis. , Dynamic modeling of such custom networks allows the investigation of cross-talk between multiple pathways.…”

New Insights into the Treatment of Glomerular Diseases: When Mechanisms Become Vivid

“…Besides T cell dependent mechanism, CsA directly interferes with B cell migration by disrupting the O 2 sensing molecular switch, destabilizing HIF-1α, and preserving responsiveness of B cells to C-X-C Motif Chemokine Receptor 4 (CXCR4). Restoration of the hypo-responsiveness to CXCR4 disrupts the coordinated localization of B cell in dark zones and light zones of germinal center and suppresses B cell response [ 256 ]. Tacrolimus is another, more potent CNI with different intracellular binding proteins (i.e., FK binding protein), associated with less nephrotoxicity [ 257 ].…”