Biology subjects

Kim, S. H. J.

Publications and source records attributed to Kim, S. H. J..

3 recordsLinked to original sources

bioRxiv2026

Non-canonical IL-2 signaling facilitates peripheral regulatory T cell differentiation

Non-canonical IL-2 signaling, termed Monoclonal antibody or Matrix-directed Alternative Cytokine Signaling (MACS), is mediated by a CD25-chemokine receptor complex and operates in concert with the canonical JAK-STAT5 pathway; however, its role in T cell homeostasis remains poorly defined. Here, we uncover a role for MACS in regulatory T cell (Treg) differentiation and functional specification. We generated Il2E66K/E66K mice in which CD25-CCR7 assembly is disrupted and IL-2-induced STAT5 phosphorylation is preserved. Immunophenotyping analysis by flow cytometry revealed that MACS deficiency reduces the accumulation of Nrp1- Foxp3+ Tregs in gut-associated lymphoid tissues from 24-weeks-old Il2E66K/E66K mutant mice. Single-cell transcriptomics, functional suppression assays, and in vitro differentiation revealed that MACS engagement drives Treg differentiation and sustains effector Treg programs - marked by robust IL-10 expression - in part via an AP-1-dependent transcriptional network. These findings establish IL-2 MACS as a distinct signal directing peripheral immune tolerance and highlight a potential node for targeted immunomodulation.

immunology↗

bioRxiv2025

A CD25-CCR7 complex initiates non-canonical IL-2 signaling

IL-2, a central regulator of immune function, binds to its receptor subunit CD25 (IL-2R), promoting IL-2 interaction with {beta} and {gamma} subunits to trigger the canonical IL-2 signaling pathway. An anti-mouse CD25 antibody, PC61, triggers alternative IL-2 signaling, leading to integrin activation. PC61 induces a complex formed by the IL-2-dependent association of CD25 with CCR7, suggesting that the formation of this complex initiates alternative IL-2 signaling. Here, we used structure-based design together with combinatorial screening to identify an IL-2 mutant (denoted IL-2(E52K)) that spares canonical IL-2 signaling but disrupts both PC61-induced complex formation and integrin activation while retaining the full CD25 affinity of the parent molecule. We also report that heparan sulfate (HS), a physiological ligand of IL-2 that triggers alternative signaling, induced IL-2-dependent CD25-CCR7 association, whereas IL-2(E52K) failed to support both HS-induced CD25-CCR7 complex formation and integrin activation. Thus, both anti-CD25 antibody and HS require common features of IL-2 needed for CD25-CCR7 complex assembly and resulting integrin activation. Collectively, these data show that IL-2 promotes CD25 interaction with CCR7, thereby forming the signal initiating complex. Furthermore, canonical and alternative IL-2 signaling can be decoupled by an IL-2 mutation, creating a tool to specify the biological role of alternative IL-2 signaling in immune responses.

cell biology↗

bioRxiv2019

The role of integrin αv and CD44 in GBM migration in human brain

Glioblastoma (GBM) is the most common primary adult malignant brain tumor. Recurrence is driven invading tumor cells that escape surgical resection and demonstrate resistance to standard-of-care chemotherapy and radiotherapy. A large body of research has been conducted on tumor cell motility. However, typical in vitro models make use of polystyrene culture dishes, which exhibit significantly different physical parameters than brain tissue. Here we report on the use of human organotypic brain slices as an ex vivo approach for the dynamic study of GBM cell motility. Temporal lobectomy tissue from epilepsy patients was obtained and cut into 350{micro}m thick slices. After the tissue slices had a weeks incubation for recovery, fluorescently labeled tumor cells were seeded. We then tracked individual tumor cells using time-lapse fluorescent confocal microscopy. Quantification of motility characteristics, including mean squared displacement, total path length, and consistency, allowed for comparison of different conditions, including knockdown of cell surface proteins integrin v (ITGAV) and CD44. Human organotypics demonstrated minimal variability across specimen in terms of motility parameters, including total path length, averaged instantaneous velocity, and consistency. Knockdown of the traditional motility protein ITGAV showed little effect on overall motility while knockdown of CD44 resulted in a significant reduction in both averaged instantaneous velocity and total path length. When the same parameters were examined using Matrigel, ITGAV and CD44 both showed decreased motility, highlighting the impact of the physical environment on cell behavior. Finally, cell motility in mouse organotypic slices was decreased when compared to human organotypic slices. Here we demonstrate the use of human organotypic brain slices in the study of GBM cell invasion. This model system offers a physiologically-relevant environment in which to examine the dynamic process of cell motility.

cancer biology↗