Biology subjects

Zick, Y.

Publications and source records attributed to Zick, Y..

4 recordsLinked to original sources

bioRxiv2026

Galectin-8 Modulates Membrane CD44v Localization and Tempers STAT3 Signaling in Gastric Metaplasia

ABSTACTGalectin-8 is a lectin that binds N-acetyllactosamine moieties with preference towards those with acidic, terminal modifications (-O-sialyated, 3-O-sulfated). As CD44-variants (CD44v) are biomarkers of metaplasia and cancer, a hyaluronic acid receptor that modulates STAT3 signaling, and specifically expresses 3-Sialyl-LeA/X glycotopes, we asked whether galectin-8 might play a role in gastric metaplasia. Using a synchronous, chemically induced murine model that produces gastric spasmolytic polypeptide expressing metaplasia (SPEM), we compared Lgals8-/- mice to congenic wild-type C57BL/6J mice. We found that galectin-8 was necessary for membrane localization of CD44v on SPEM cells at the base of the glands, suggesting a physical interaction between galectin-8 and CD44v. Metaplastic glands from Lgals8-/- mice had an increase in nuclear pSTAT3 compared to C57BL/6J mice, suggesting that galectin-8 restrains CD44 -> STAT3 signaling. This effect was more prominent in the neck compared to the base, which has greater abundance of CD44v after injury in Lgals8-/- mice. Derepression of STAT3 signaling may explain why low galectin-8 levels is associated with a worse prognosis in gastric cancer.

cancer biology↗

bioRxiv2025

Multimerin1, not Galectin-8, Promotes Gastric Chief Cell Differentiation by Tempering WNT Signaling

Galectins are a family of proteins that bind galactose-containing glycans. One member, galectin-8, preferentially binds galactose that contains a terminal sulfate. Aberrant expression and secretion of sulfated glycosylation epitopes, such as 3-Sulfo-LeA/C, is a feature of high-risk human foregut metaplasias. In addition, recent work has demonstrated that 3-Sulfo-LeC is a marker of mature murine zymogenic chief cells of the stomach and that 3-Sulfo-LeC epitope is secreted via cathartocytosis during the cellular transition to a metaplastic state. Based on those findings, we used Lgals8-/-mice, to determine whether galectin-8 might play a role in chief cell homeostasis. We observed delayed gastric differentiation in the Lgals8-/-mice and discovered that this phenotype was due to an unappreciated deletion of Mmrn1 and Snca in the Lgals8-/- line. We show that multimerin-1 tempers WNT stimulation of the gastric corpus at an early age, as evidenced by nuclear beta-catenin staining and proliferation throughout the gland. Because multimerin-1 is synthesized and secreted from endothelial cells and not from the epithelial compartment, these data uncover a role for mesodermal cells in epithelial developmental and maturation of the mouse stomach. As prior studies have suggested galectin-8 and multimerin-1 have overlapping functions albeit, divergent with respect to bone, future studies using pure knockouts are necessary to refine these phenotypes.

developmental biology↗

bioRxiv2024

The Deubiquitinating Enzyme Otub2 Modulates Pancreatic Beta-Cells Function and Survival

We have previously shown that otubain 2 (OTUB2), a deubiquitinating enzyme, inhibits caspase-3/7 activity in primary human islets; promotes insulin secretion and inhibits cytokine-induced nuclear factor-{kappa}B (NF{kappa}B) activity. In the present work we show that overexpression of Otub2 in MIN6 cells inhibits NF{kappa}B activity and the expression of its target genes MCP-1 and iNOS. Consequently, both the basal and the cytokine-induced apoptosis of cultured MIN6 cells and dispersed human islets were inhibited. Overexpression of Otub2 in MIN6 cells increase the mRNA levels of NKx6.1 and Glut2 and concomitantly increased glucose-stimulated insulin secretion (GSIS) (by 2-3-fold). The beneficial effects of Otub2 on {beta}-cell function was demonstrated by the phenotype of Otub2-/+ and Otub2-/- mice, which manifested impaired glucose tolerance and increased expression of NFkB target genes (e.g. IP-10, MCP-1 and IL-1{beta}). RNAseq analysis of pancreata derived from OTUB2 KO mice revealed reduced expression of genes that down regulate K+ transporters (e.g. Ank2, Cacna1a and Kcnab1) combined with an increase in oxidative phosphorylation related genes. Given that closure of K+ channels is crucial for insulin secretion, these results could account, at least in part, for the impaired GSIS in the OTUB2 KO mice. Indeed, mass-spectrometry analysis of proteins co-immunoprecipitated with Otub2 revealed the voltage-gated potassium channel subunit Kv9.3 as a major Otub2 binding-partner. Additional binding partners included the Peg3 and Camk2d proteins, which promote NF{kappa}B signaling and {beta}-cell death. Hence, by deubiquitinating proteins in complexes that contain Peg3 and Camk2d, Otub2 might inhibit propagation of NF{kappa}B signaling and {beta}-cell apoptosis. Collectively our findings implicate Otub2 as a key regulator of {beta} cell function, mainly affecting NFkB signaling and the K+ channels that regulate insulin secretion.

cell biology↗

bioRxiv2020

Differential cellular responses to adhesive interactions with galectin-8 and fibronectin coated substrates

The mechanisms underlying the cellular response to extracellular matrices (ECM), consisting of multiple adhesive ligands, each with distinct properties, are still poorly understood. Here we address this topic by monitoring the cellular responses to two very different extracellular adhesion molecules - fibronectin and galectin-8 - and to mixtures of the two. Fibronectin is one of the major integrin ligands, inducing cell spreading and development of focal adhesions associated with contractile stress fibers. Galectin-8 is a mammalian lectin, which specifically binds to {beta}-galactoside residues present on some integrins, as well as to other cell surface receptors. We found marked differences in HeLa-JW cell spreading, assembly of focal adhesions and actomyosin stress fibers, and formation of adherent filopodia, on rigid flat substrates functionalized by fibronectin or galectin-8 alone, or by mixtures of these two proteins. Spreading on galectin-8 resulted in a larger projected cell area compared to that on fibronectin, by more extensive formation of filopodia, coupled with an inability to activate focal adhesion and stress fiber assembly. These differences could be partially reversed by experimental manipulations of small G-proteins of the Rho family and their downstream targets, such as formins, the Arp2/3 complex, and Rho kinase. Another factor affecting the spreading process was shown to be the enhanced physical adhesion of the cells to galectin-8, as compared to fibronectin. Notably, at least one process, the formation of adherent filopodia, was synergistically upregulated by both ligands, so filopodia development on the substrate coated with a mixture of fibronectin and galectin-8 was far more prominent than on each ligand alone.

cell biology↗