Publications

2024

Pan, W., & Tsokos, G. C. (2024). Reverse aging to treat lupus.. European Journal of Immunology, e2451274. https://doi.org/10.1002/eji.202451274 (Original work published 2024)

Systemic lupus erythematosus (SLE) is a complex autoimmune disease with multifaceted pathogenetic processes, including abnormalities of T-cell subset distribution and function. Accumulation of senescent CD4+ T cells has been found to contribute to the development of the disease. In this issue, Jiang et al. provide compelling evidence that links an expanded pool of CD4+CD57+ senescent T cells in patients with SLE to disease activity favored by interleukin-15. Importantly, treatment of lupus-prone mice with a senolytic drug resulted in decreased autoimmune pathology. The findings of this study suggest possible novel therapeutics to treat patients with SLE.

Tsokos, G. C. (2024). The immunology of systemic lupus erythematosus.. Nature Immunology, 25(8), 1332-1343. https://doi.org/10.1038/s41590-024-01898-7 (Original work published 2024)

Understanding the pathogenesis and clinical manifestations of systemic lupus erythematosus (SLE) has been a great challenge. Reductionist approaches to understand the nature of the disease have identified many pathogenetic contributors that parallel clinical heterogeneity. This Review outlines the immunological control of SLE and looks to experimental tools and approaches that are improving our understanding of the complex contribution of interacting genetics, environment, sex and immunoregulatory factors and their interface with processes inherent to tissue parenchymal cells. Efforts to advance precision medicine in the care of patients with SLE along with treatment strategies to correct the immune system hold hope and are also examined.

Schmauch, E., Severin, Y., Xing, X., Mangold, A., Conrad, C., Johannsen, P., Kahlenberg, M., Mellett, M., Navarini, A., Nobbe, S., Sarkar, M. K., Satyam, A., Tsoi, L. C., French, L. E., Nilsson, J., Linna-Kuosmanen, S., Kaikkonen, M. U., Snijder, B., Kellis, M., … Kolios, A. G. A. (2024). Targeting IL-1 controls refractory pityriasis rubra pilaris.. Science Advances, 10(27), eado2365. https://doi.org/10.1126/sciadv.ado2365 (Original work published 2024)

Pityriasis rubra pilaris (PRP) is a rare inflammatory skin disease with a poorly understood pathogenesis. Through a molecularly driven precision medicine approach and an extensive mechanistic pathway analysis in PRP skin samples, compared to psoriasis, atopic dermatitis, healed PRP, and healthy controls, we identified IL-1β as a key mediator, orchestrating an NF-κB-mediated IL-1β-CCL20 axis, including activation of CARD14 and NOD2. Treatment of three patients with the IL-1 antagonists anakinra and canakinumab resulted in rapid clinical improvement and reversal of the PRP-associated molecular signature with a 50% improvement in skin lesions after 2 to 3 weeks. This transcriptional signature was consistent with in vitro stimulation of keratinocytes with IL-1β. With the central role of IL-1β underscoring its potential as a therapeutic target, our findings propose a redefinition of PRP as an autoinflammatory keratinization disorder. Further clinical trials are needed to validate the efficacy of IL-1β antagonists in PRP.

Pan, W., Tsokos, M. G., Scherlinger, M., Li, W., & Tsokos, G. C. (2024). The PP2A regulatory subunit PPP2R2A controls NAD+ biosynthesis to regulate T cell subset differentiation in systemic autoimmunity.. Cell Reports, 43(7), 114379. https://doi.org/10.1016/j.celrep.2024.114379 (Original work published 2024)

The protein phosphatase 2A (PP2A) regulatory subunit PPP2R2A is involved in the regulation of immune response. We report that lupus-prone mice with T cells deficient in PPP2R2A display less autoimmunity and nephritis. PPP2R2A deficiency promotes NAD+ biosynthesis through the nicotinamide riboside (NR)-directed salvage pathway in T cells. NR inhibits murine Th17 and promotes Treg cell differentiation, in vitro, by PΑRylating histone H1.2 and causing its reduced occupancy in the Foxp3 loci and increased occupancy in the Il17a loci, leading to increased Foxp3 and decreased Il17a transcription. NR treatment suppresses disease in MRL.lpr mice and restores NAD+-dependent poly [ADP-ribose] polymerase 1 (PARP1) activity in CD4 T cells from patients with systemic lupus erythematosus (SLE), while reducing interferon (IFN)-γ and interleukin (IL)-17 production. We conclude that PPP2R2A controls the level of NAD+ through the NR-directed salvage pathway and promotes systemic autoimmunity. Translationally, NR suppresses lupus nephritis in mice and limits the production of proinflammatory cytokines by SLE T cells.

Xu, M., Ito-Kureha, T., Kang, H.-S., Chernev, A., Raj, T., Hoefig, K. P., Hohn, C., Giesert, F., Wang, Y., Pan, W., Ziętara, N., Straub, T., Feederle, R., Daniel, C., Adler, B., König, J., Feske, S., Tsokos, G. C., Wurst, W., … Heissmeyer, V. (2024). The thymocyte-specific RNA-binding protein Arpp21 provides TCR repertoire diversity by binding to the 3’-UTR and promoting Rag1 mRNA expression.. Nature Communications, 15(1), 2194. https://doi.org/10.1038/s41467-024-46371-z (Original work published 2024)

The regulation of thymocyte development by RNA-binding proteins (RBPs) is largely unexplored. We identify 642 RBPs in the thymus and focus on Arpp21, which shows selective and dynamic expression in early thymocytes. Arpp21 is downregulated in response to T cell receptor (TCR) and Ca2+ signals. Downregulation requires Stim1/Stim2 and CaMK4 expression and involves Arpp21 protein phosphorylation, polyubiquitination and proteasomal degradation. Arpp21 directly binds RNA through its R3H domain, with a preference for uridine-rich motifs, promoting the expression of target mRNAs. Analysis of the Arpp21-bound transcriptome reveals strong interactions with the Rag1 3'-UTR. Arpp21-deficient thymocytes show reduced Rag1 expression, delayed TCR rearrangement and a less diverse TCR repertoire. This phenotype is recapitulated in Rag1 3'-UTR mutant mice harboring a deletion of the Arpp21 response region. These findings show how thymocyte-specific Arpp21 promotes Rag1 expression to enable TCR repertoire diversity until signals from the TCR terminate Arpp21 and Rag1 activities.

Alduraibi, F. K., & Tsokos, G. C. (2024). Lupus Nephritis Biomarkers: A Critical Review. Int J Mol Sci, 25, Article 2. https://doi.org/10.3390/ijms25020805805ijms25020805 [pii]ijms-25-00805 [pii]
Lupus nephritis (LN), a major complication in individuals diagnosed with systemic lupus erythematosus, substantially increases morbidity and mortality. Despite marked improvements in the survival of patients with severe LN over the past 50 years, complete clinical remission after immunosuppressive therapy is achieved in only half of the patients. Therefore, timely detection of LN is vital for initiating prompt therapeutic interventions and improving patient outcomes. Biomarkers have emerged as valuable tools for LN detection and monitoring; however, the complex role of these biomarkers in LN pathogenesis remains unclear. Renal biopsy remains the gold standard for the identification of the histological phenotypes of LN and guides disease management. However, the molecular pathophysiology of specific renal lesions remains poorly understood. In this review, we provide a critical, up-to-date overview of the latest developments in the field of LN biomarkers.
Furuya, H., Nguyen, C. T., Chan, T., Marusina, A. I., Merleev, A. A., Garcia-Hernandez, M. L., Hsieh, S. L., Tsokos, G. C., Ritchlin, C. T., Tagkopoulos, I., Maverakis, E., & Adamopoulos, I. E. (2024). IL-23 induces CLEC5A(+) IL-17A(+) neutrophils and elicit skin inflammation associated with psoriatic arthritis. J Autoimmun, 143, 103167. https://doi.org/S0896-8411(24)00001-5 [pii]10.1016/j.jaut.2024.103167
IL-23-activation of IL-17 producing T cells is involved in many rheumatic diseases. Herein, we investigate the role of IL-23 in the activation of myeloid cell subsets that contribute to skin inflammation in mice and man. IL-23 gene transfer in WT, IL-23R(GFP) reporter mice and subsequent analysis with spectral cytometry show that IL-23 regulates early innate immune events by inducing the expansion of a myeloid MDL1(+)CD11b(+)Ly6G(+) population that dictates epidermal hyperplasia, acanthosis, and parakeratosis; hallmark pathologic features of psoriasis. Genetic ablation of MDL-1, a major PU.1 transcriptional target during myeloid differentiation exclusively expressed in myeloid cells, completely prevents IL-23-pathology. Moreover, we show that IL-23-induced myeloid subsets are also capable of producing IL-17A and IL-23R(+)MDL1(+) cells are present in the involved skin of psoriasis patients and gene expression correlations between IL-23 and MDL-1 have been validated in multiple patient cohorts. Collectively, our data demonstrate a novel role of IL-23 in MDL-1-myelopoiesis that is responsible for skin inflammation and related pathologies. Our data open a new avenue of investigations regarding the role of IL-23 in the activation of myeloid immunoreceptors and their role in autoimmunity.
Scherlinger, M., Li, H., Pan, W., Li, W., Karino, K., Vichos, T., Boulougoura, A., Yoshida, N., Tsokos, M. G., & Tsokos, G. C. (2024). CaMK4 controls follicular helper T cell expansion and function during normal and autoimmune T-dependent B cell responses. Nat Commun, 15, Article 1. https://doi.org/10.1038/s41467-024-45080-x84010.1038/s41467-024-45080-x [pii]45080 [pii]
Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by dysregulated B cell compartment responsible for the production of autoantibodies. Here, we show that T cell-specific expression of calcium/calmodulin-dependent protein kinase IV (CaMK4) leads to T follicular helper (T(fh)) cells expansion in models of T-dependent immunization and autoimmunity. Mechanistically, CaMK4 controls the T(fh)-specific transcription factor B cell lymphoma 6 (Bcl6) at the transcriptional level through the cAMP responsive element modulator alpha (CREMalpha). In the absence of CaMK4 in T cells, germinal center formation and humoral immunity is impaired in immunized mice, resulting in reduced anti-dsDNA titres, as well as IgG and complement kidney deposition in the lupus-prone B6.lpr mouse. In human T(fh) cells, CaMK4 inhibition reduced BCL6 expression and IL-21 secretion ex vivo, resulting in impaired plasmablast formation and IgG production. In patients with SLE, CAMK4 mRNA levels in T(fh) cells correlated with those of BCL6. In conclusion, we identify CaMK4/CREMalpha as a driver of T cell-dependent B cell dysregulation in autoimmunity.

2023

Bhargava, R., Li, H., & Tsokos, G. C. (2023). Pathogenesis of lupus nephritis: the contribution of immune and kidney resident cells. Curr Opin Rheumatol, 35, Article 2. https://doi.org/10.1097/BOR.000000000000088700002281-202303000-00007 [pii]
PURPOSE OF REVIEW: Lupus nephritis is associated with significant mortality and morbidity. We lack effective therapeutics and biomarkers mostly because of our limited understanding of its complex pathogenesis. We aim to present an overview of the recent advances in the field to gain a deeper understanding of the underlying cellular and molecular mechanisms involved in lupus nephritis pathogenesis. RECENT FINDINGS: Recent studies have identified distinct roles for each resident kidney cell in the pathogenesis of lupus nephritis. Podocytes share many elements of innate and adaptive immune cells and they can present antigens and participate in the formation of crescents in coordination with parietal epithelial cells. Mesangial cells produce pro-inflammatory cytokines and secrete extracellular matrix contributing to glomerular fibrosis. Tubular epithelial cells modulate the milieu of the interstitium to promote T cell infiltration and formation of tertiary lymphoid organs. Modulation of specific genes in kidney resident cells can ward off the effectors of the autoimmune response including autoantibodies, cytokines and immune cells. SUMMARY: The development of lupus nephritis is multifactorial involving genetic susceptibility, environmental triggers and systemic inflammation. However, the role of resident kidney cells in the development of lupus nephritis is becoming more defined and distinct. More recent studies point to the restoration of kidney resident cell function using cell targeted approaches to prevent and treat lupus nephritis.
Jiang, X., Xiao, X., Li, H., Gong, Y., Wang, M., Yang, H., Zhao, L., Jiang, Y., Wei, Y., Zhao, C., Li, J., Chen, Y., Feng, S., Deng, H., Ma, S., Xu, Y., Liu, Y., Tsokos, G. C., Jiang, M., & Zhang, X. (2023). Oxidized galectin-1 in SLE fails to bind the inhibitory receptor VSTM1 and increases reactive oxygen species levels in neutrophils. Cell Mol Immunol, 20, Article 11. https://doi.org/10.1038/s41423-023-01084-z10.1038/s41423-023-01084-z [pii]1084 [pii]
Inhibitory immune receptors set thresholds for immune cell activation, and their deficiency predisposes a person to autoimmune responses. However, the agonists of inhibitory immune receptors remain largely unknown, representing untapped sources of treatments for autoimmune diseases. Here, we show that V-set and transmembrane domain-containing 1 (VSTM1) is an inhibitory receptor and that its binding by the competent ligand soluble galectin-1 (Gal1) is essential for maintaining neutrophil viability mediated by downregulated reactive oxygen species production. However, in patients with systemic lupus erythematosus (SLE), circulating Gal1 is oxidized and cannot be recognized by VSTM1, leading to increased intracellular reactive oxygen species levels and reduced neutrophil viability. Dysregulated neutrophil function or death contributes significantly to the pathogenesis of SLE by providing danger molecules and autoantigens that drive the production of inflammatory cytokines and the activation of autoreactive lymphocytes. Interestingly, serum levels of glutathione, an antioxidant able to convert oxidized Gal1 to its reduced form, were negatively correlated with SLE disease activity. Taken together, our findings reveal failed inhibitory Gal1/VSTM1 pathway activation in patients with SLE and provide important insights for the development of effective targeted therapies.