Biology subjects

Unlu, S.

Publications and source records attributed to Unlu, S..

6 recordsLinked to original sources

bioRxiv2026

Multi-hit STAG2 mutations define a high-risk subset of MDS and reveal convergent evolutionary targeting of cohesin

STAG2 is the most frequently mutated cohesin gene in myeloid neoplasms, yet the significance of multiple mutations within this X-linked tumor suppressor remains unknown. We analyzed a cohort of 1,967 adult patients with myeloid neoplasms and identified 233 cases (12%) harboring STAG2 mutations, including 38 cases (16%) with multiple STAG2 hits. Patients with multi-hit STAG2 mutations exhibited increased multilineage dysplasia compared with single-hit cases and experienced inferior overall survival, an effect driven primarily by patients with myelodysplastic syndromes (MDS). To investigate the molecular basis of recurrent STAG2 acquisition, we performed long-read sequencing in representative cases with phaseable STAG2 mutations. In the informative case examined, distinct truncating STAG2 mutations did not co-occur on the same DNA molecule, supporting independent acquisition rather than stepwise allelic inactivation. Cohort-level variant allele frequency patterns were consistent with recurrent evolutionary targeting of STAG2 across related clonal populations. Together, these findings support a model in which multi-hit STAG2 mutations arise through convergent evolution and define a biologically distinct, adverse-risk subset of MDS.

cancer biology↗

bioRxiv2026

Rapid and efficient generation of human 8-cell-like cells for embryo modelling

8-cell blastomeres of human embryos possess broad lineage potential and undergo major zygotic genome activation (ZGA), yet experimental access to this transient cell state remains limited. Rare 8-cell-like cells (8CLCs) arise spontaneously in naive pluripotent stem cell cultures, but their low abundance has constrained mechanistic and functional studies. Here, we develop a chemically defined strategy for rapid and robust induction of 8CLCs. Through sequential small-molecule screens focused on chromatin regulators, we identify five compounds acting through distinct pathways that generate up to 40% 8CLCs within 48 hours. The resulting cells, which we term rapidly induced 8CLCs (ri8CLCs), recapitulate key molecular features of 8-cell blastomeres, including induction of ZGA-associated genes, cleavage-stage transposable elements, and 8-cell-stage transcriptional signatures in bulk and single-cell transcriptomic analyses. Functionally, ri8CLCs exhibit enhanced developmental competence, acquiring the ability for spontaneous extraembryonic differentiation and assembly into well-cavitated blastoids on an accelerated 72-hour timeline. Notably, ri8CLC induction enables blastoid formation even in the absence of MEK inhibition, TGF-{beta}/Activin/Nodal inhibition and exogenous LIF, revealing a developmental competence consistent with an early embryonic state. Together, these findings establish a rapid, defined, and highly efficient platform for generating human ri8CLCs and provide a tractable model for studying early human embryogenesis.

developmental biology↗

bioRxiv2026

Glucose-Responsive CD20+ Cytotoxic T Cells: A Novel Pro-inflammatory Mediator in the Immunopathogenesis of Type 2 Diabetes

ObjectiveAlthough T-cell-mediated inflammation is a hallmark of Type 2 Diabetes (T2D), the contribution of CD20-expressing T cells--a highly potent subset recently implicated in various autoimmune conditions--to T2D pathogenesis remains unknown. This study aimed to characterize the frequency, functional profile, and glucose-responsiveness of CD20+ cytotoxic T lymphocytes (CTLs) in patients with T2D. Research Design and MethodsPeripheral blood mononuclear cells (PBMCs) from 25 treatment-naive T2D patients and 20 age-matched healthy controls (HC) were analyzed using multicolor flow cytometry. We assessed the frequency of CD3+CD8+CD20+ cells and their production of cytotoxic molecules (Granzyme B, Perforin, Granzyme K) and pro-inflammatory cytokines (IFN-{gamma}, TNF-, GM-CSF). To further establish the link with hyperglycemia, HC-derived CTLs were exposed to increasing glucose concentrations (100-450 mg/dL) in vitro. Single-cell RNA sequencing (scRNA-seq) data from a public T2D dataset was utilized to validate the molecular signature of MS4A1 (CD20)+ CTLs. ResultsThe frequency of circulating CD20+ CTLs was significantly elevated in T2D patients compared to HCs (p<0.0001) and demonstrated a strong positive correlation with HbA1c, fasting glucose, and triglyceride levels. Notably, CD20+ CTLs from T2D patients exhibited a "hyperfunctional" phenotype, characterized by significantly higher degranulation (CD107a), elevated expression of Granzymes B/K and Perforin, and increased production of IFN-{gamma} and TNF- compared to HCs (p<0.01 for all). In contrast, no such differences were observed in the CD20-CTL compartment. In vitro experiments revealed that escalating glucose levels directly enhanced the proliferation and cytotoxic potential of CD20+ CTLs, suggesting a nutrient-sensing mechanism. scRNA-seq analysis further confirmed the distinct pro-inflammatory and effector transcriptional profile of MS4A1+ T cells in T2D. ConclusionsOur findings identify CD20+ CTLs as a novel, glucose-sensitive, and hyperfunctional immune subset in T2D. The strong correlation between these cells and clinical metabolic parameters suggests that CD20+ CTLs may act as a critical link between chronic hyperglycemia and systemic inflammation, representing a potential new therapeutic target for immunomodulation in T2D.

immunology↗

bioRxiv2026

CD8+CD20+ Cytotoxic T Lymphocytes Exhibit Augmented Degranulation and Pro-inflammatory Potential in Multiple Sclerosis

The effectiveness of CD20-targeting therapies in multiple sclerosis (MS) underscores the role of B cells in the disease, yet the limited success of other B cell-specific treatments suggests additional mechanisms at play. Intriguingly, CD20 is also expressed on a subset of highly active memory T cells, particularly cytotoxic CD8+ T lymphocytes (CTLs). This study investigated the functional characteristics of CD8+CD20+ CTLs in MS. We observed a significant increase in CD8+CD20+ CTL prevalence in MS patients, with enhanced infiltration into the cerebrospinal fluid. Consistent with prior reports, these cells exhibited heightened proliferation and production of IFN-{gamma}, TNF-, and GM-CSF. Notably, we demonstrate for the first time that CD8+CD20+ CTLs display escalated degranulation and produce significantly higher levels of Granzyme B, Perforin, and Granzyme K compared to their CD20-counterparts, with further augmentation in pwMS compared to healthy controls. These findings suggest that in MS, CD8+CD20+ CTLs are actively recruited to the CNS, exhibiting enhanced cytotoxicity and a potent pro-inflammatory profile, particularly through elevated Granzyme K production, contributing significantly to the chronic inflammatory milieu and immunopathogenesis of MS.

immunology↗

bioRxiv2026

Identification of Lupus Immune Complex-Driven Pathogenic Pro-inflammatory Monocytes and Macrophages in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE or lupus) is an autoimmune disease characterized by anti-nuclear antibody (ANA) production and inflammation, though the mechanisms by which ANAs induce inflammation and tissue injury are incompletely understood. Here, we identified distinct subsets of mononuclear phagocytes (MPs), including monocytes (Mo) and macrophages (M{Phi}), driven by lupus immune complex (IC), comprised of ANAs and their target antigens. scRNA-seq of human Mo incubated with U1-snRNP (snRNP) lupus IC revealed expansion of distinct pro-inflammatory Mo subsets with upregulation of inflammatory genes including those encoding cytokines, NLRP3, and transcription factors. These transcriptomic changes strongly correlated with protein expression, as determined by proteomic analysis. Mo developed similar pro-inflammatory transcriptomic changes in response to other lupus ICs containing anti-dsDNA and Ro60 antibodies. Interrogation of scRNA-seq datasets from the skin, kidney, and peripheral blood of lupus patients revealed the presence and expansion of pro-inflammatory Mo and M{Phi} populations exhibiting transcriptomic signatures similar to those observed in lupus IC-stimulated Mo. Some of these cells expressing the snRNP IC gene signature exhibited low expression of the type I IFN signature, suggesting that lupus IC and type I IFN signaling may independently affect Mo subsets. In lupus nephritis, infiltration of CD68+ M{Phi} expressing NLRP3 was associated with treatment outcomes. Inhibiting activation of the transcription factor ETS2, a master regulator of Mo/M{Phi}-driven inflammation, attenuated lupus IC-induced activation of pro-inflammatory Mo. Collectively, these findings provide novel insights into the role of lupus IC-driven pro-inflammatory MPs in the pathogenesis of SLE and highlight their relevance as therapeutic targets. Significance StatementSystemic lupus erythematosus (SLE or lupus) is a multi-systemic autoimmune inflammatory disease characterized by anti-nuclear antibody (ANA) production. Lupus immune complex (IC), consisting of ANAs and their target antigens, likely play a critical role in the pathogenesis of lupus through activation of mononuclear phagocytes (MPs), including monocytes (Mo) and macrophages (M{Phi}), which can produce an array of inflammatory molecules. Using transcriptomic and proteomic analyses, our study identified distinct pro-inflammatory Mo populations driven by lupus IC, along with expansion of similar pro-inflammatory Mo and M{Phi} subsets in the skin, kidneys, and peripheral blood of lupus patients. These findings provide novel insights into the pathogenic role of lupus IC-driven pro-inflammatory MPs and support a scientific rationale for therapeutically targeting these cells. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=155 HEIGHT=200 SRC="FIGDIR/small/700902v2_ufig1.gif" ALT="Figure 1"> View larger version (43K): org.highwire.dtl.DTLVardef@1839430org.highwire.dtl.DTLVardef@175dd1dorg.highwire.dtl.DTLVardef@107b54forg.highwire.dtl.DTLVardef@11096b0_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2022

Altered CD8+ T cell associated aging gene signature in the peripheral blood of patients with Alzheimer's disease.

INTRODUCTIONEffector memory (EM) CD8+ T cells have been associated with poor cognition in Alzheimers disease (AD). Our lab recently discovered an age-associated gene expression signature of IL-7 receptor alpha (IL-7R)low EM CD8+ T cells. We hypothesized that individuals with AD have altered levels of this IL-7Rlow aging gene expression. METHODSForty genes associated with IL-7Rlow EM CD8+ T cells, AD, or memory, were analyzed in peripheral blood of participants with normal cognition, mild cognitive impairment, and dementia by qPCR. RESULTSOf the eight genes that were found to be differentially expressed based on clinical diagnosis, 5 genes (62.5%) were IL-7Rlow aging genes. Principal component analysis revealed 3 clusters of participants with dementia which had distinct expression levels of IL-7Rlow aging genes and cognitive function. DISCUSSIONOur findings support the possible relationship of the IL-7Rlow EM CD8+ T cell aging signature with cognition in individuals with dementia due to AD.

immunology↗